Dissipationless Mergers of Elliptical Galaxies and the Evolution of the Fundamental Plane

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did平行趋势检验时间范围

did平行趋势检验时间范围1. 什么是did平行趋势检验？did平行趋势检验（Difference-in-Differences Parallel trend test）是一种经济学中常用的处理因果推断问题的方法。

也被称为事件研究设计或断点回归设计。

这种方法可以通过比较处理组和对照组在时间上的趋势来评估政策、活动或干预措施对所研究的结果变量的影响。

在一个did设计中，研究对象被分成两组：处理组和对照组。

处理组接受了一项特定政策、活动或干预措施，而对照组没有接受该项措施。

通过比较处理组和对照组之间的差异变化，可以确定该措施的效果是否存在。

在did平行趋势检验中，我们假设在措施实施之前，处理组和对照组的趋势是平行的，即两组在措施实施之前的发展趋势相似。

如果这个假设成立，即处理组和对照组没有系统性的差异，那么任何随后的差异可以归因于措施本身。

2. 如何确定did平行趋势检验的时间范围？确定did平行趋势检验的时间范围需要考虑以下因素：2.1 实验前期趋势首先，我们需要检查处理组和对照组在措施实施之前的趋势是否平行。

这可以通过观察两组在措施实施之前的数据来确定。

如果处理组和对照组的趋势在措施实施之前存在显著差异，那么did平行趋势检验可能不适用。

2.2 措施实施时间点确定了实验前期趋势后，我们需要确定措施的实施时间点。

措施的实施时间点应当尽可能明确，确保处理组和对照组在实施前后不存在混淆。

通常，措施的实施时间点应当在处理组和对照组的趋势发生明显改变的时间之前。

2.3 控制时间段在确定了措施的实施时间点后，我们需要确定控制时间段。

控制时间段是指在实施措施之前和实施之后，没有受到干预的时间范围。

这个时间段用来比较处理组和对照组在实施之前和实施之后的变化。

控制时间段的选择应考虑到数据的可用性和趋势的稳定性。

通常，控制时间段应当包含了足够的时间观察期，以确保我们能够捕捉到可能存在的季节性和周期性变化。

3. did平行趋势检验的实施步骤实施did平行趋势检验的基本步骤如下：3.1 数据收集首先，我们需要收集处理组和对照组在措施实施前后的相关数据。

Mergers and Acquisitions

Mergers and Acquisitions External growth and restructuringof firms.Jyoti Gupta1Market for corporate control•Mergers and acquisitions are part of the broader market for corporate control. It is not only acquisition of company by another, it includes spin-offs, divestitures, restructurings of capital structure, buy-outs and buy out of public companies by groups of private investors. The ordinary mergers involve combination of two established firms.2Mergers•Horizontal mergers: between two firms in the same line of business. Acquisition by Altadis of Régie des Tabacs du Maroc, Acquisition, Total-Fina and Elf etc. Alcatel and Lucent which merged officially on the 1 December 2006.•Vertical Mergers:companies at different stages of production; Disney and ABC television. •Conglomerate merger: unrelated line of business; Vivendi and Seagram.3Rationale of mergers•The rationale behind any merger operation is to create value for the shareholders. This also supposes that all other stakeholders would be better-off if the merger operation is carried through.•All other motives are secondary.4Motives for mergers (Efficiencygains)•Economies of scale.•Increased revenues/ increased market share •Improved productivity through cost cutting •Surplus funds.•Economies of scope.•Reusability of information.•Reputational spill over.•Better product mix.•Resource transfer by overcoming information asymmetry or by combining scarce resouces.5Strategic reasons•Increased competition•Domino effect.•Too big to fail.•Empire building.6M&A process•Many firms have a pro-active approach to M & A operations as a source of growth, value creation and restructuring.•They could be friendly or hostile. In case the firms are listed, the operations are subject to clearance from regulatory authorities. The authorities want to make sure that the operation will not lead to creation of a monopoly. The case Schnieder and Legrange, the European Commission refused the merger between the two.8M&A process•In the case of listed companies, the acquiring company makes a take-over bid for the target company. An offer is made to the shareholders of the company (cash,exchange of shares, or a mix of the two).•In a friendly bid, the Board of Directors of the two companies agree to the proposition. The Boardrecommends to shareholders to accept the offer by the acquiring company. The post merger strategy is jointly agreed upon.•In a hostile bid, the target company board recommends to the shareholders to refuse the offer.9M&A Process (A pro-active approach byAcquiring company)•Clear definition of objectives and goals.• A preliminary analysis of possible target companies.•Estimation of possible synergies, timing and probability.•Valuation of the target company, stand alone and as a merged company.•Preparation of an offer, including a due diligence report from the investment bank.•Final offer.•Negotiation and settlement.13Role of the investment banks•The investment banks play an important role in the M&A operations.•The aquiring company and the target company would normally appoint an investment bank (may be more than one) as advisers in the operation.•They advise at all stages of the operations, which includes the valuation, synergy valuation, structure of the deal, carry out the due diligence, provide funding gurantee, funding and post mergersupport in putting the new business model in place.•These operations represent a significant part of their revenues.•Most investment banks have M&A departments, which are often divided in sectors (Telecommunications, agro, commodities etc).•The investment banks often are at the source of operation, advising companies on the likely targets.•These operations are called pitching; preparing the necessary documents to present to potential acquirers.•They represent a significan part of the revenues.14Due Diligence (an example)•Material Adverse Effect:•This clause in the due diligence document can enable the Acquiring company to walk away from the deal even once the final offer ismade.•The Bank of America (BofA) purchase of Merrill Lynch, is a good example.•The Bof A agreed to buy Merrill Lynch for $50 billion in stocks,or $29 share, in December 2008.•Once the offer was made, the BA executives started having doubts, as ML started to show losses. By the end of the month, the losses exceeded $13 billion.•Most of the losses were coming from trading department, ans also the wealth management unit.•BofA executives discussed the possibility citing «Material Adverse Effect »clause to severe the contract.15Merger gains and costs•Gain = PV(A+B) –PV(A)-PV(B)•PV(A), PV(B) and PV(A+B), being the values of the firms A , B stand alone and the two firms if they merge. Merger is justified only if there is a synergy gain.•Cost to the acquiring firm A is given bycost=Cash paid-PV(B).•The synergy gain is usually shared between the acquiring firm and the shareholders of the target firm.16Paid in stocks: example•Bidder or Acquiring company, share price 200, number of shares 200; PV(A) =40000•Target company B, share price 100, number of shares 100, PV(B) = 10000•New Company after merger (A+B), has 260 shares, shares are trading at 230, PV(A+B)= 59800. Thesynergy gains as estimated by the market is 9800.• A pays the shareholders of B, 60 shares of A. An exchange ratio of 60/100 ,ie0.6 shares of A for eachshare of B.•Cost to the shareholders of A of the operation =60/260 x59800=13800-10000=3800.22Merger accounting, an example•We look at two companies A and B•Company A is the acquirer and the company B is the target.•The balance sheets are given. The Shareholders equity of the target company B is 1000.•Company A pays a premium of 500 to the shareholders of B. The purchase price is 1500. It might be paying for the intangible assets, which are not in the balance sheet.•Under the purchase method, the accountant takes of this by creatinga new asset called goodwill and assigns 500 to it in the balancesheet of the merged company.•The shareholders equity of the merged company = 2800 + 1000 + 500 = 4300. The equity of the merged company goes by the value of the premium paid.31Goodwill and Taxation •Goodwill are not allowed to be amortized.•Suppose the goodwill (premium paid over the book value) is €10 million.•As long as the goodwill is estimated to be at least €10 million, it stays on the balance sheet and it has noimpact on the company’s earnings.•The company is obliged each year to estimate the fair value of the goodwill.•If the estimated value falls below the €10 million, the amount shown in the balance sheet must be adjusted downward and the write-off deducted from the year’searnings. The example of AOL, write-off $54 billion.35Tax Considerations•An acquisition may be either taxable or tax-free.•In general, if the payment is in cash, the acquisition is considered as taxable.•Investors pay capital gains tax.•If payment is essentially in shares, the operation is considered to be tax free, as they are simply exchanging shares.•The tax status of the acquisition also effects the tax paid by the merged firm afterwards.•In the case of a taxable acquisition, the assets of the selling firm are revalued, the write-up or write-down is treated as taxable gain or taxable loss. The depreciation is calculated on the basis of the restated asset values.36Tax considerations: an example•The Norman Shipping Company buys a tanker for $20 million.This is the only asset owned by the company. It is depreciated over 20 years linearly; yearly depreciation = $1 million. The Norman was acquired by Pat Shipping corporation after 10 years for $15 million. What would be tax liabilities if it was a taxable merger or a tax-free merger?37Takeover defenses•Given the increasing number of firms which are likely to be target, management team try to develop tactics and weapons of defense. These are used in the case of hostile take-over bids. •Increasingly, govenments are intervening to stop foreign companies taking over national companies ( Sanofi Synthelabo, Danone, Arcelor).•Major motivation being, firstly managers believe their jobs will be at risk, secondly they would like to obtain a higher price from the bidders.39Merger and antitrust law•Most countries have antitrust laws, which forbids acquisitions if it leads to the lessening of competition and creation of monopolies.•In the US, the Clayton Act (1914), forbids an acquisition whenever the effect may limit and restrict competition.•The European Community has strict antitrust laws. An acquisition is forbidden if it leads to the creation of a company which holds more than 50 percent of market in any one European country or more 30 % of the Euopean market.•The proposed merger between GDF and Suez is being scrutinized by the European Antitrust commission on the question of monopoly.•The investment banks should ensure that the merger will not be prohibited as part of the due diligence.43M&A:General observations•The analysis of the M&A operations in the past gives some interesting results:The sellers generally do better than buyers.The average gain of the shareholders of the target company was around 16 percent.The shareprices of the acquiring company decline on average.Studies show that a significant proportion of M&A operations destroy value.The question is why ? This is explained by behavioral finance. Themanagers of acquiring companies may be driven by hubris oroverconfidence in their ability to run the target company than the existing managers.Another explanation is based on signalling effect of an mergerannouncement; the firm can grow by greenfield investment or acquisition.The acquisition is justified when the overall market is not growing. Therefore the firm value might drop simply because the market interprets that thesector growth is limited.44Observations•Why sellers get higher returns:–Premium paid because of competition–Get a share of the estimated synergy–Target management may put obstacles, white knight, antitrust law, poison pill to push theprice up.The other major winners are of course theinvestment banks, lawyers, accountants,arbitrageurs etc.45Take-over bid by Sanofi-Synthélbo forAventis(25 January 2004)•Objective: Strategic project for a sustainable strong growth and profitability.•The details were as follows:•An offer based on exchange of shares and cash payment: 5 SS shares + 69€for 6 Aventis shares.• A supplementary offer (cash or exchange) cash offer: purchase of Aventis share for 60.43€. Exchange offer: Exchange 35 SS shares for 34 shares of Aventis.•Shareholders were given the possibility to choose a mix of the above two possibilities.•The overall offer was based on 81 % of exchange of shares and 19 % in cash.49。

专业英语

Definition of polymers A simple understanding of polymers can be gained by imaging them to be like a chain or, perhaps, a string of pearls, where the individual pearl represent small molecules that are chemically bonded together. Therefore, a polymer is a molecule made up of smaller molecules that are joined together by chemical bonds. The word polymer means „many parts or units.‟ The parts or units are the small molecules that combine. The result of the combination is, of course, a chainlike molecule (polymer). Usually the polymer chains are long, often consisting of hundreds of units, but polymers consisting of only a few units linked together are also known and can be commercially valuable.
Figure 1.1 Diagram illustrating the definition of plastics.
As Figure 1.1 shows, all materials can be classified as gases, simple liquids, or solids, with the understanding that most materials can be converted from one state to another through heating or cooling. If only materials that are structural solids at normal temperatures are examined, three major types of materials are encountered: metals, polymers, and ceramics. The polymer materials can be further divided into synthetic polymers and natural polymers. Most synthetic polymers are those that do not occur naturally and are represented by materials such as nylon, polyethylene, and polyester. Some synthetic polymers could be manufactured copies of naturally occurring materials (such as

社会科学研究方法与论文写作智慧树知到期末考试章节课后题库2024年北京第二外国语学院

社会科学研究方法与论文写作智慧树知到期末考试答案章节题库2024年北京第二外国语学院1.What are key components of research design? （）答案:Timeframe.###Sampling Strategy.###Data Collection Methods.2.The following aspects of informed consent that are essential in researchethics include （）.答案:Researchers explaining potential risks andbenefits.###Participants being allowed to withdraw from the study.3.When should all authors be included in the in-text citation, according to theAPA style? （）答案:When there are two authors.###When there are three to fiveauthors.4.What are some essential tips for writing an effective abstract? （）答案:Use keywords###Emphasize points differently from thepaper.###Use passive verbs5.Which statements are suggested solutions for improving the Methodologysection? （）答案:Eliminate the use of first-person pronouns.###Provide a clearrationale for the chosen methods.6.What's the difference between methodology and method? （）答案:Methodology encompasses the broader theoretical framework and guiding philosophy of the research process.###Methods encompass the specific techniques and procedures employed for data collection andanalysis.###Methodology is presented as a distinct section in aresearch thesis, explaining the overall approach and rationale.7.What are the downsides of mere listing in a literature review? （）答案:It does not present themes or identify trends.###It often indicatesa lack of critical synthesis.8.The common problems to be aware of in thesis writing include（）.答案:Excessive reliance on qualitative data###Lack of theoreticalsupport###Failure to integrate theory and practice.###Misuse of tense ponents that are typically embedded in the structure of an academicpaper, especially the journal article, include （）答案:Introduction###Results and Discussion10.Which of the following examples are misconducts? （）答案:Facilitating academic dishonesty.###Unauthorizedcollaboration###Misuse of Patients11.What are the three main elements of a definition, as mentioned in the lecture?（）答案:Term, Category, and Features.12.In the Methods section, why is it important to detail the tools or materials fordata collection? （）答案:To explain how instruments to be used to answer researchquestions.13.Which is the method suggested to avoid plagiarism when summarizinginformation from sources? （）答案:Summarize immediately after reading without referring back tothe source.14.The purpose of control variables in research is （）.答案:To keep certain factors constant and prevent them frominfluencing the dependent variable.15.What is the purpose of using sampling techniques in research? （）答案:To draw conclusions about the population based on data collected from the sample.16.According to Wallwork’s tips for the final check, what is one way to ensureyour paper is as good as possible before submission? （）答案:Anticipate referees’ comments.17.What does external validity assess? （）答案:The extent to which research findings can be applied orgeneralized to other situations and populations.18.Which of the following expressions are correctly used in the Methods Section?（）答案:"We conducted the experiment in a controlled environment."19.Which of the following is NOT a recommended guideline for using tables in aresearch paper? （）答案:Using as many tables as possible to provide comprehensiveinformation.20.What does a structured abstract typically include to make it more readable?（）答案:Eye-catching font for the title21.What is the main function of the preparation stage in writing a literaturereview? （）答案:To locate relevant literature and prepare for writing.22.The primary focus of academic integrity is （）.答案:Fostering honesty and responsible behavior.23.The act of using someone else’s ideas and writings as your own can beconsidered as （）.答案:Plagiarism24.Which step is NOT part of the suggested three-step approach for revisingyour paper? （）答案:Rewrite the entire paper.25.Which is not the reason for an overly broad title being problematic? （）答案:It encourages depth in the study.26. A good thesis or dissertation should tell the reader not just “what I havedone,” but “why what I have done matters.” （）答案:对27.Coherence in academic writing refers to the clarity of the thesis statementand the organization of the paper. （）答案:对28.The research methods section helps readers and reviewers gauge thetransparency, validity, and reliability of the research. （）答案:对29.Research papers are published to share new, original results and ideas withthe academic community. （）答案:对30.Relying solely on secondary sources ensures the originality of researchfindings. （）答案:错31.In introduction writing, it is recommended to delve into an exhaustive reviewof the entire field to provide comprehensive context. （）答案:错32.The Background Method in introduction writing kicks off by presenting aproblem and then addressing the solution. （）答案:错33.Multiculturalism seeks to enhance the self-esteem and identities ofmarginalized groups. （）答案:对34. A Doctoral-level literature review is typically less comprehensive than aMaster's-level literature review. （）答案:错35."Hoaxing" involves deliberately publishing false information with theintention of deceiving others. （）答案:对36.Reflecting on the research process at the end is essential for evaluating itsstrengths and limitations. （）答案:对37. A well-crafted title should engage a wide audience effectively. （）答案:对38.In order to avoid plagiarism, it is suggested to avoid citing references. （）答案:错39.Predicting difficulties and providing countermeasures in a research proposalis essential to show the depth of thinking and enlist expected guidance. （）答案:对40.Conducting a literature review is not necessary when selecting a researchtitle. （）答案:错41.What can authors do to ensure a timely publication in a journal that reviewspapers for job hunting purposes?（）答案:Submit the manuscript without checking for errors###Seekinformation from editors about review times###Be efficient in making revisions42.When preparing a manuscript for publication, it is crucial to focus on ethicalstandards.（）答案:对43.Why do researchers want to publish their papers?（）答案:To share new results and ideas44.How can you identify an appropriate journal for publication? （）答案:Look for journals that publish work similar to your research.45.The editor-in-chief makes the final decision on whether a submitted paper isaccepted or rejected in the review process.（）答案:对ing cut and paste extensively is recommended during the final check tosave time.（）答案:错47.Exchanging texts with another student for proofreading is encouraged to findcareless errors in your own work.（）答案:对48.What is the key idea that should be remembered by the audience from yourtalk？（）答案:The key idea of your research49.Why is it important to avoid errors that may distort meaning in your writtenwork? （）答案:To enhance the quality of your writing###To ensure clarity ofcommunication50.What is the main purpose of doing a presentation?（）答案:To engage, excite, and provoke the audience51.Making academic writing more tentative involves avoiding over-generalizations and using linguistic hedges and tentative phrases.（）答案:对52.What is the purpose of the checklist questions provided for paper revision?（）答案:To help improve the writing53.Which of the following are strategies for achieving cohesion in academicwriting? （）答案:Organizing the paper logically###Using transitional words andphrases###Employing reference words54.Redundancy and colloquialisms are considered desirable features ofconciseness in academic writing. （）答案:错55.What should you do when revising your paper writing to improve clarity andspecificity? （）答案:Be self-contained56.What are the characteristics of informative abstracts? （）答案:They may replace the need for reading the full paper###Theycommunicate specific information about the paper###They provide aconcise summary of the paper’s content57.Structured abstracts may have clear subheadings to mark different sections.（）答案:对58.What is the recommended maximum word limit for a conference abstract?（）答案:250 words59.Which tense is often used when writing an abstract? （）答案:Present tense60.The primary purpose of an informative abstract is to indicate the subjectsdealt with in a paper. （）答案:错61.What are some reasons for using citations in academic writing? （）答案:To show you are a member of a particular disciplinarycommunity###To acknowledge the intellectual property rights ofauthors###To avoid plagiarism62.Self-plagiarism is not considered an ethical concern in academic writing.（）答案:错63.What is the primary purpose of citation in academic writing? （）答案:To acknowledge the intellectual property rights of authors64.What is self-plagiarism? （）答案:Presenting one's own previously published work as new65.All sources cited in the text must be documented in the References section.（）答案:对66.Which type of conclusion is more common in research papers and theses andfocuses on summarizing research outcomes and aligning them with the initial thesis? （）答案:Thesis-oriented Conclusion67.What are the four sections typically found in the Conclusion section of aresearch paper, according to the material? （）答案:Summary of findings, implications, limitations, further studies68.What is one of the purposes of the conclusions chapter? （）答案:To forestall criticisms by identifying limitations of the research69.Which of the following are types of conclusions discussed in the material? （）答案:Summary type###Field-oriented conclusion###Evaluation type of conclusion###Recommendation type of conclusion70.The conclusion section in academic papers typically follows a uniformstructure across all disciplines.（）答案:错71.What is one of the purposes of making comparisons with previous studies inacademic writing? （）答案:To justify the methods or procedures followed72.Which of the following is NOT mentioned as a common type of graphicalfigure in the material? （）答案:Map illustrations73.What can we do in demonstrating our research results in paper? （）答案:Use figures and tables to summarize data###Show the results ofstatistical analysis74.In which field are Qualitative Research methods often used?（）答案:Liberal Arts and Social Sciences75.What factors should be considered when choosing research methods for athesis? （）答案:Traditional approaches.###Research questions andobjectives.###Nature of the subject matter.76.What does "Research Design" refer to in the research process?（）答案:The overall plan guiding the research study.77.All the following moves are included in the method section except （）.答案:Describing the commonly used methods in certain field.78.The research methods section in a thesis is often presented as a distinctsection, separate from the literature review.（）答案:对79.What are the two core abilities essential for writing an effective literaturereview? （）答案:Information seeking and critical appraisal.80.Where can a literature review be placed in a research paper or thesis? （）答案:In different places depending on research goals and fieldconventions.81.Which type of literature review focuses on organizing literature aroundspecific research questions?（）答案:Question-oriented review.82.The purpose of creating a visual representation, such as a literature map, isto replace the need for drafting concise summaries.（）答案:错83.What are the recommended tenses to use when discussing the content of thesources in a literature review? （）答案:Simple Past.###Present Perfect.###Simple Present.84.What is the role of the Problem Statement in the Introduction? （）答案:Justify the importance of the research.85.Which is NOT one of the three methods could be used to write anintroduction? （）答案:Reference Method86.The location and structure of the introduction are standardized across alltypes of research theses. （）答案:错87.In Metadiscourse research, what is the recommended way for a researcher torefer to themselves in the introduction?（）答案:Refer to themselves as "this thesis" or a specific section.88.What are the key elements included in Move 2 of the "Create a ResearchSpace" (CARS) framework?（）答案:Identifying gaps in prior research.###Indicating a gap.89.What role do Research Grant Proposals play?（）答案:Both securing financial support and convincing funding agencies.90.What questions does a research proposal eloquently answer? （）答案:How are you going to do it?###What do you plan toaccomplish?###Why do you want to do it?91.The "Aims/Purposes" section in a research proposal outlines the centralissues to be tackled in the study. （）答案:对92.To whom is a research proposal usually submitted for approval and support?（）答案:Funding agencies, academic institutions, or research supervisors.93.What is the purpose of predicting difficulties and providing countermeasuresin the research proposal?（）答案:To show the depth of thinking and enlist expected guidance.94.The recency of sources is crucial in research, and older sources are alwayspreferred for their depth.（）答案:错95.Which database is specifically mentioned for searching Master's and DoctoralDissertations? （）答案:CNKI96.When conducting a critique of a study, what should be considered about themethods used?（）答案:The validity for studying the problem.97.What is the primary characteristic of primary sources in research materialcollection? （）答案:They offer synthesized information from various perspectives. 98.What are common approaches to collecting primary source materialsmentioned in the lecture? （）答案:Surveys and questionnaires###Controlled experiments###One-on-one interviews99.What are potential mistakes in the title selection process? （）答案:Having unclear titles that do not convey the subjectmatter.###Using contemporary language to make the title appearoutdated.100.How does the researcher balance the focus of a research title?（）答案:By clearly defining the scope of the study.101.What is the purpose of conducting a comprehensive literature review in the title selection process? （）答案:To identify gaps, controversies, or areas requiring furtherexploration.102.An overly narrow title might limit the potential impact and relevance of the research. （）答案:对103.What is the significance of a well-chosen title? （）答案:It significantly enhances the academic value of the work.104.What are key characteristics of deconstruction in literary theory? （）答案:Highlighting textual undecidability and paradoxes.###Challenging traditional assumptions about language and meaning.###Questioning binary oppositions.105.What distinguishes quantitative data from qualitative data in research? （）答案:Quantitative data are numerical, while qualitative data can bedescribed in words.106.What is the primary goal of case studies in applied linguistics? （）答案:To enhance understanding of a phenomenon, process, person, or group.107.Case studies use a single data source, such as interviews, to explore particular phenomena. （）答案:错108.What are the three types of cultural studies? （）答案:New historicism, postcolonialism, American multiculturalism. 109.The dependent variable in a study investigating the effects of different study methods on exam performance is （）.答案:Exam performance110.What role does a moderating variable play in a research study? （）.答案:It influences the strength or direction of the relationship between independent and dependent variables.111.External validity assesses the extent to which research findings can be applied to populations, settings, or conditions beyond the specific study. （）答案:对112.How does deduction differ from induction in research? （）答案:Deduction is the process of reasoning from general principles tospecific predictions.113.The purposes of research include （）答案:Solving real-world problems###Testing existingtheories###Meeting graduation requirements###Advancingknowledge114.The potential academic consequences for students who engage in academic dishonesty include （）.答案:Monetary fines、Academic suspension and Expulsion from theInstitute115.The three key principles that experimental researchers need to carefully consider and implement before, during and after recruiting researchparticipants are （）.答案:Anonymity###Informed consent###Confidentiality116.It is unethical to conduct research which is badly planned or poorly executed.（）答案:对117.The primary focus of academic integrity in the context of research ethics is （）.答案:Fostering responsibility and trustworthiness in academic work 118.The pillars of academic integrity include all the aspects except （）答案:Excellence119.The primary purpose of literature reviews in research articles is （）.答案:To evaluate previously published material120.Methodological articles typically present highly technical materials, derivations, proofs, and details of simulations within the main body of thearticle. （）答案:对121.In a research article, many different sections can be found in empirical studies, including （）.答案:Method###Literature review###Introduction###Discussion 122.According to the lecture, which step in the procedures of thesis writing involves drafting a title and abstract? （）答案:Step 1: Choice of Topic123.The primary use of case studies is （）.答案:To illustrate a problem or shed light on research needs。

新核心综合学术英语教程 4 Unit 3 参考答案

Focusing on ReadingTask 11.G2. E3. C4. F5. A6. D7.J8. B9.L10.H 11. N 12. M 13. Q 14.K 15. I 16.R 17.O 18.PTask 21)The reasons are as follows”Firstly, students sometimes view academic dishonesty as a normal incidence and something ordinary. There are many reasons that they use to justify their cheating.Secondly, new techniques of cheating have been developed, including the use of high-tech tools, although the old ones are still dominant on campus, which makes it even more difficult for the faculty to identify.Thirdly, it is a common view to equate grades with the value of the student. Furthermore, grades are used to predict one’s future success. So some students tend to practice academic dishonesty with the aim of getting higher grades.Fourthly, little is known about the degree of academic dishonesty and no methods are devised to combat the problem. Besides, there are no strategies for deterring academic dishonesty for the faculty.Fifthly, honor codes are essential to reducing the level of cheating in colleges and should be established. However, their importance has been neglected.Last but not least, academic dishonesty is no longer a task of classroom management that can well be remedied by a single faulty with teaching responsibility. Administrators and professional organizations are expected to work together to maintain a healthy learning environment with a high level of trust between the faculty and the administration.2)Old techniques include bringing notes to class and having information written on water bottles,pens and gum wrappers. New techniques of cheating include using cell phones to get the information, communicate with others outside the exam room to obtain answers and searching answers on the web during an exam.Other forms include copying test responses from a classmate, taking exams for other people, failure to cite other people’s work, and purchasing research papers and presenting them as his/her work. Also actions such as breaking into the office or teachers files to access the test or answer key, sabotaging peers ongoing work or gaining illegal access to school computers to change official grades are all forms of academic dishonesty. (B)3)There are many reasons that students use to justify cheating: lack of time, poverty, uncaringinstructors, laziness, peer pressure, poor rile models, fear of failure and technology that has allowed cheating to be done easily. (C)Besides, research shows that a common view equates grades with the value of the student.Secondly, grades are used to predict one’s future success. This may cause the students to practice academic dishonesty.4)Studies show that honor codes were essential to reducing the level of cheating in colleges.Honor codes would be more successful when they were combined with a climate that emphasized the importance of academic integrity and an honor system that allowed for strong student involvement in the enforcement of academic integrity initiatives. Therefore, the administration should strive in the creation of the campus environment, seek the full support of all the college constituents, and ensure the implementation of the honor codes at theinstitution. (N)5)Academic fraternity means “all the people who work in academia.”It can stress integrity as a core institutional value that will shape the students’academic success.Task 31. a2. j3. W4. m5. k6. o7. v8. x9.n 10.b 11. u 12.y 13.d14. i 15. f 16. z 17. t 18.p 19. S 20. q 21. e 22. g 23. c 24. h 25. l 26. rTask 51)Another kind of academic dishonesty happens sometimes among researchers when they yieldto the temptation of making a series of great discoveries. So they invent false information to deceive others, and then publish them.2)Bouville(2010) held that the major reason for the students to avoid academic dishonesty wasto obey the rules and escape punishment. Cheaters may get high grades which they do not deserve, and this unfair advantage will tempt them to continue with this fraudulent behaviour.3)Third, in each department there should be experienced faculty members, acting as academicintegrity chairmen, who are responsible for contacting and offering help to their fellow colleagues. Lastly, for faculty members who have tackled the cases of academic dishonesty well, public thanks and admiration should be given to them for what they have done.Task 6Main idea: Students developed new techniques of cheating, while the old ones are still dominant on campus.Task 7In the area of education, academic dishonesty is a chronic problem. Students have developed new techniques of cheating, while the old ones are still dominant on campus. Cheaters follow dishonest practices because of many reasons. Prevention of academic dishonesty demands joint efforts from students, teachers and administrators, of which the students’ contribution is vital for they are the ones to be subjected to the penalties. For the teachers, they can adopt four strategies to maintain academic integrity and meanwhile make efforts to motivate the students. For the administrators, they should strive in the creation of a healthy academic climate and ensure the implementation of the honor codes.Task 8(omitted)Task 9(omitted)Task 10Academic DishonestyAcademic dishonesty occurs when a student uses or attempts to use unauthorized information in the taking of an exam; or submits as his or her own work themes, reports, drawings, laboratory notes, or other products prepared by another person; or knowingly assists another student in such acts or plagiarism. Such behavior is abhorrent to the university, and students found responsible for academic dishonesty face expulsion, suspension, conduct probation, or reprimand. Instances of academic dishonesty ultimately affect all students and the entire university community by degrading the value of diplomas when some are obtained dishonestly, and by lowering the grades of students working honestly.Examples of specific acts of academic dishonesty include but are not limited to:a) Obtaining unauthorized information. Information is obtained dishonestly, for example, bycopying graded homework assignments from another student, by working with another student on a take-home test or homework when not specifically permitted to do so by the instructor, or by looking at your notes or other written work during an examination when not specifically permitted to do so.b) Tendering of information. Students may not give or sell their work to another person who plans to submit it as his or her own. This includes giving their work to another student to be copied, giving someone answers to exam questions during the exam, taking an exam and discussing its contents with students who will be taking the same exam, or giving or selling a term paper to another student.c) Misrepresentation. Students misrepresent their work by handing in the work of someone else. The following are examples: purchasing a paper from a term paper service; reproducing another person’s paper (even with modifications) and submitting it as their own; having another studentdo their computer program or having someone else take their exam.d) Bribery. Offering money or any item or service to a faculty member or any other person to gain academic advantage for yourself or another is dishonest.e) Plagiarism. Unacknowledged use of the information, ideas, or phrasing of other writers is an offense comparable with theft and fraud, and it is so recognized by the copyright and patent laws. Literary offenses of this kind are known as plagiarism.One is responsible for plagiarism when: the exact words of another writer are used without using quotation marks and indicating the source of the words; the words of another are summarized or paraphrased without giving the credit that is due; the ideas from another writer are borrowed without properly documenting their source.Acknowledging the sources of borrowed material is a simple, straightforward procedure that will strengthen the paper and assure the integrity of the wri ter. The Student’s Guide to English 104 —105, provides guidelines to aid students in documenting material borrowed from other sources, as does almost every handbook on writing style.Academic dishonesty is considered to be a violation of the behavior expected of a student in an academic setting as well as a student conduct violation. A student found responsible for academic dishonesty or academic misconduct is therefore subject to the appropriate academic penalty; to be determined by the instructor of the course, as well as sanctions under the university Student Disciplinary Regulations.If an instructor believes that a student has behaved dishonestly in a course, the following steps are to be followed:1. The instructor should confront the student with the charge of dishonesty and arrange a meetingwith the student to discuss the charge and to hear the student’s explanation.2. If the student admits responsibility for academic misconduct, the instructor shall inform the student (a) of the grade on the work in which the dishonesty occurred, and (b) how this incident will affect subsequent evaluation and the final grade. Because academic dishonesty is also a student conduct violation under Section 4.2.1 of the Student Disciplinary Regulations, the instructor must report the incident in writing to the Dean of Students.After investigating the incident and discussing it with the instructor, the Dean of Students, or his/her designee, will meet with the student and depending on the severity of the offense as well as on the student’s past conduct record, may handle the matter through an administrative hearing or schedule a hearing before the All University Judiciary (AUJ).This hearing, conducted according to the procedures outlined in the Student Disciplinary Regulations, is to determine the disciplinary action to be taken. In any case, the student’s academic adviser will be informed of the incident but may not insert any record of it in the student’s academic file.3. If the student claims to be not responsible for the alleged violation of academic misconduct, the instructor may not assign the student a grade for the work in question until the question of responsibility is resolved, unless circumstances require that an interim grade be assigned. The instructor shall consult with his or her department chair and report the incident in writing to the Dean of Students.The Dean of Students will refer the case to the Office of Judicial Affairs for investigation. After reviewing the report and completing an investigation, the Office of Judicial Affairs will file aformal complaint against the student if it is determined that there is cause to believe academic misconduct occurred. The case may be adjudicated through an administrative hearing or referred to a hearing before the All University Judiciary (AUJ) depending on the nature and severity of the violation as set forth in the Student Disciplinary Regulations.If the case is referred to the AUJ both the student and instructor will be invited to attend an AUJ hearing and present pertinent information. If the Administrative Hearing Off icer (in a minor case) or the AUJ (in a major case) finds the student responsible for the charge of academic misconduct, the instructor will inform the student (a) of the grade on the work in which the dishonesty occurred, and (b) how this incident will affect subsequent evaluation and the final grade. The Administrative Hearing Officer or AUJ will determine the appropriate disciplinary action with respect to the nature of the violation.If the Administrative Hearing Officer or AUJ finds the student “not responsible” for academic misconduct, the instructor will grade the student accordingly on the work in question and the student’s grade in the course will not be adversely affected. If th e student is found responsible the student’s adviser will be informed of the decision but shall not insert any record of the action in the student’s academic file.4. If a student either admits dishonest behavior or is found responsible for academic misconduct by the AUJ, the Off ice of Judicial Affairs (OJA) or AUJ may impose any of the following sanctions:a) Disciplinary Reprimand: An official written notice to the student that his/her conduct is in violation of university rules and regulations.b) Conduct Probation: A more severe sanction than a disciplinary reprimand, to include a period of review and observation during which the student must demonstrate the ability to comply with university rules, regulations, and other requirements stipulated for the probation period.c) Suspension/Deferred Suspension: The suspension is deferred subject to a definite or indefinite period of observation and review. If a student is found responsible for a further violation of the university Student Disciplinary Regulations or an order of a judiciary body, suspension will take place immediately.Def i niteThe student is dropped from the university for a specific length of time. This suspension cannot be for less than one semester or more than two years.Indef i nite:The Student is dropped from the university indefinitely. Reinstatement may be contingent upon meeting the written requirements of the AUJ specified at the time the sanction was imposed. Normally, a student who is suspended indefinitely may not be reinstated for a minimum of two years.d) Expulsion: The student is permanently deprived of the opportunity to continue at the university in any status.5. A student accused of academic misconduct has the option to stay in the class or to drop the class if the drop is made within the approved time periods and according to the regulations established by the university. If the student chooses to drop the class, the student will be required to sign a statement of understanding that if the student is later found responsible for academic misconduct, then the student will receive an F for the course.6. Procedures for appeal of either the All University Judi ciary’s conduct decision or theinstructor’s grade are outlined in the Student Information Handbook.7. In instances in which the student admits responsibility or is judged to be responsible by OJA or the AUJ, a staff member of the Dean of Students Off ice will counsel the student in an effort to deter any further such incidents.8. Student records concerning academic dishonesty are maintained in the Dean of Students Office for a period of seven years, after which the file records are purged. These student records are confidential; nothing from them appears on a student’s academic transcript.9. In the event that an instructor is uncertain how to handle an incident of suspected academic dishonesty, the Dean of Students is available at any time to provide advice and assistance to the instructor in deciding a proper course of action to be taken.10. Students enrolled in the College of Veterinary Medicine are bound by an honor code. A chargeof academic dishonesty may be made by a student or instructor to the Interclass Honor Board chairperson according to the procedures outlined in the Honor Code, or the instructor may follow procedures outlined above. The Interclass Honor Board functions as the judiciary of the College of Veterinary Medicine for the allegations presented to it.Other violations related to academic misconduct may include subsection 4.1.11 Misuse of Computers and subsection 4.2.20 Unauthorized Sale of Others’Intellectual Works.These subsections are located in the Iowa State University Student Disciplinary Regulations under section 4 of the Conduct Code.</~catalog/2005-07/geninfo/dishonesty.html>Short reportAcademic dishonesty occurs when a student uses or attempts to use unauthorized information in the taking of an exam; or submits as his or her own work themes, reports, drawings, laboratory notes, or other products prepared by another person; or knowingly assists another student in such acts or plagiarism. Such behavior is abhorrent to the university, and students found responsible for academic dishonesty face expulsion, suspension, conduct probation, or reprimand. Instances of academic dishonesty ultimately affect all students and the entire university community by degrading the value of diplomas when some are obtained dishonestly, and by lowering the grades of students working honestly.Examples of specific acts of academic dishonesty include obtaining unauthorized information, tendering of information, misrepresentation, bribery, plagiarism, etc. Academic dishonesty is considered to be a violation of the behavior expected of a student in an academic setting as well as a student conduct violation.In Iowa State University, a student found responsible for academic dishonesty or academic misconduct is therefore subject to appropriate academic penalty or to be determined by the instructor of the course, as well as sanctions under the university Student Disciplinary Regulations. If an instructor believes that a student has behaved dishonestly in a course, ten steps are to be followed to handle the problem. The case of Iowa State UniversityResearch Paper WritingTask 1Background part:The introductionObjective:To give an overview of various forms of academic dishonesty, student responses to academic dishonesty when it occurs and the measures taken by the faculty and institutional administrator to prevent its occurrence in their institutions.Synthesis of different views on a particular field: For example, in the section “Forms of Academic Dishonesty,” in Para. B, there are opinions of both Jonson and Martin (2005) and Petress (2003), which are organized by transitional words, such as “Petress noted of other forms of academic dishonesty ...”Similarities or differences of outside sources:For example, in the section “Faculty and Academic Dishonesty”, when it comes to what the faculty should do to reduce academic dishonesty, there are various opinions from Para J to L. Perress (2003) holds that they should set role models for the students and implement the measures that will help prevent academic dishonesty. Whitley and Keith-Spiegel believe that they should be encouraged to form a statement concerning academic integrity in their syllabi and to discuss integrity concerns in their classrooms. Kibler notes four strategies to help the faculty to implement academic integrity. Cole and Kiss suggest that more efforts should be made to motivate the students by the teachers.Task 2a. The forms of cheating.Text 3 deals with students’ new and old techniques of cheating, together with researchers’ practices of academic dishonesty.Reading 1 focuses on academic dishonesty in online courses.Reading 1 gives more updated and reliable information.b. The reasons that students offer for their cheating.In Text 3 the reasons the students use to justify their cheating include: lack of time, poverty, uncaring instructors, laziness, peer pressure, poor role models, fear of failure and technology that has allowed cheating to be done easily. (Para. C)In Reading 1, the reasons are multifold because opinions vary. Some of the reasons are based on a student’s individual characteristics (Gerdeman 2001), some are relevant to peer inf luence or peers’acceptability of cheating (Stephens, 2007), while others have something to do with the existence of an honor code (McCabe, 2002). Meanwhile, there are other common reasons by Chiesl and Bunn, of which seeing other students cheat and the perception of the percentage of students who cheat are the most significant. (Para. I,J,K)Reading 1 gives more updated and reliable information.c. The definition of academic dishonesty.In Text 3, there is no specific definition of academic dishonesty.In Reading 1, the author believes that definitions of academic dishonesty across studies tend to be about the same. Using the scale of Don McCabe (2002), the author defines academic dishonesty from eight aspects. Other studies differentiate planned and panic cheating, e.g., Bunn, Caudill and Gropper (1992). In a comparative study of online versus on-ground academic dishonesty, Stuber- McEwen, Wisely, and Hoggat (2009) believe that there are seven forms. Stephens, Young, and Calabrese (2007) examined various forms of conventional and digital cheating. With regard toe-learning, Underwood (2003) and Rogers (2000) def ine the term respectively, while Howell et al (2009) reviews various forms of technological cheating. (Para.B, C, D, E, F, G)Reading 1Task 31) Serious and formal2) Angry and bitter3) Angry and ironical4) Angry and ironical5) Ironical6) Ironical7) Angry and ironical8) Angry9) Ironical10) Tranquil and formal11) Tranquil12) Tranquil and formal13) Formal and serious14) Formal and serious15) Expressing the speaker’s surprise and attitude against this16) Tranquil17) Expressing surprise, Ironical18) Appealing to the readers’ emotions by the use of questions, Ironical19) Appealing to the readers’ emotions by the use of questions, Angry and ironical20) “You” is used in the sentence to indicate people in general to appeal to their emotions, whichshortens the distance between the speaker and the readers21) Appealing to the readers’ emotions by the use of questions22) Appealing to the readers’ emotions by the use of facts and questions. Expressing the speaker’sdisagreementTask 41) Which one is a stand-alone literature review and which one is a literature review as a partof the paper?Text 3 and Reading 1: stand-alone literature reviewReading 2: literature review as a part of the paper2) What similarities and differences characterize the three papers in terms of writing style?Similarities: All of them follow almost the same pattern, i.e., introduction, body, and conclusion.Differences: Text 3 and reading 1 synthesize other people’s research and f indings to draw the conclusion, while Reading 2 uses the author’s own research and f indings. Therefore, in Reading 2 there is the part of “Methods”, which explains in detail the participants, materials, and design and procedure. The first-person narration is used to describe the process, which makes it less formal than the other two papers.3) What are the objectives of the three papers respectively?Text 3: To give an overview of various forms of academic dishonesty, student responses to academic dishonesty when it occurs and the measures taken by the faculty and institutional administrator to prevent its occurrence in their institutions.Reading 1: Examine perceptions of academic dishonesty in online and face-to-face courses, and discuss methods to reduce academic dishonesty in online courses.Reading 2: To investigate participants’ attitudes toward cheating and the effects of academic motivation, self-eff icacy, and academic integrity on cheating behaviors.4) How many aspects or sections do the two stand-alone literature review contain respectively?What are they?ThreeIntroduction, body, and conclusion5) Is the order of those aspects in each literature review logic al? And what’s the relationship?Yes.The literature review consists of three aspects: an introduction, a body, and a conclusion. The introduction part may tell the reason one is writing a review; the signif icance of the topic; the scope of the review; the organizational pattern of the review. The body will have a clear classif ication and synthesis of one’s reviewed readings in terms of chronological order or importance order. The conclusion should have a summary of the main agreements and disagreements in the literature and then any gaps or areas for further research. At last one’s overall perspective on the topic should be dealt with.6) How do the two authors illustrate their arguments in each section? Do they use their own research and f i ndings or synthesize other people’s research and f i ndings?By synthesizing other people’s research and f indings.No.Reading 2Task 51) indicate, is, identified, tend, will be2) predicted, was, have suggested, are, showed, appeared, were, wereTask 6A chimera is an individual composed of cells with different embryonic origins. The successful isolation of f ive human embryonic stem cell (HESC) lines in 1998 increased scientists’ ability to create human/non-human chimeras and prompted extensive bioethics discussion, resulting in what has been dubbed “the other stem cell debate” (Shreeve 2005). The debate about chimeras has focused on five main arguments. The Unnaturalness Argument explores the ethics of violatingnatural species boundaries. The Moral Confusion Argument alleges that the existence of entities that cannot be definitively classified as either human or non-human will cause moral confusion that will undermine valuable social and cultural practices. The Borderline-Personhood Argument focuses on great apes and concludes that their borderline-personhood confers a high enough degree of moral status to make most, if not all, chimeric research on them impermissible. The Human Dignity Argument claims that it is an affront to human dignity to give an individual “trapped” in the body of a non-human animal the capacities associated with human dignity. Finally, the Moral Status Framework maintains that research in which a non-human animal’s moral status is enhanced to that of a normal adult human is impermissible unless reasonable assurances are in place that its new moral status will be respected, which is unlikely given the motivations for chimeric research and the oversight likely to be provided.These arguments provide different rationales for restricting chimeric research and have different implications for the range of chimeric research that will be deemed unethical.</entries/chimeras/#Int>Task 71) Which sentences provide the background of the paper?Academic dishonesty is a problem that has been plaguing colleges and universities for generations. An investigation of any institution today will certainly reveal some forms of academic dishonesty.2) Which sentences form the literature review?Researchers of academic dishonesty vary in their reports of how many students cheat in college.3) What is the main limitation of the previous studies that the author mentioned?However, most research on academic dishonesty has relied primarily on self-reports of cheating behaviors.4) What’s the objective of the paper?The purpose of the study is to investigate participants’ attitudes toward cheating and the effects of academic motivation, self-efficacy, and academic integrity on cheating behaviors.5) What are the methods that the author will use?The present study includes an empirical portion in which participants are put in a situation in which cheating may be to their advantage.6) What is the author’s hypothesis?The hypothesis is that participants would be most likely to cheat when they are offered a monetary reward for success.Task 8Introduction 11) an introduction of the topic and its background2) a review about the previous studies3) the limitation of the previous studies4) a gap for the signif icance of the study5) the hypothesis of the author6) the objective of the paper7) the methodologyIntroduction 21) an introduction of the topic and its background2) a review about the previous studies and the limitation of the previous studies3) the limitation of the previous studiesTask 91) A2) B3) E4) C5) D6) FTask 10This paper details the strategies used for curbing academic dishonesty in online courses.Task 11Biologists have long known of patterns of inheritance, and eventually of inheritance mechanisms, that go beyond genetic inheritance (Jablonka & Lamb 2005; Sapp 1987). Two fundamental types of arguments led to this conclusion: arguments based on observations regarding patterns of inheritance, and arguments concerned with the localization of hereditary factors inside cells. Arguments of the first kind were based on hereditary relations and inheritance patterns that fail to conform to the rules ofMendelian inheritance (e.g., maternal inheritance). If Mendelian inheritance patterns are the result of the way the chromosomes in the eukaryotic cell nucleus behave, non-Mendelian heredity must depend on separate inheritance processes, mechanisms, or systems (Beale 1966; Sager 1966). Second, there were observations of hereditary phenomena that seemed to depend on factors residing in the cytoplasm of cells, rather than their nucleus, where the genetic material is localized. The interpretation of these observations was highly contested (Darlington 1944; Sapp 1987). Today, we know that some of these observations are related to the (maternal) inheritance of organelles residing in the cytoplasm, such as the mitochondria and chloroplasts, organelles which carry their own DNA. This however does not encompass all the mechanisms which underlie cytoplasmatic inheritance. Paradigmatic work on cytoplasmatic inheritance done by Sonneborn, Beale, Nanney, and their colleagues in the 1950s and 1960s, was concerned with patterns of inheritance in unicellular organisms, and in particular the protist genus Paramecium. It was suggested that the self-sustaining regulatory loops that maintain gene activity or inactivity in a cell would persist through cell division, provided the non-DNA components of the system (many of which reside in the cytoplasm in eukaryotic microogranisms) were shared among daughter cells. In this way, alternative regulatory phenotypic states would be inherited. Among the properties whose inheritance was studied were mating-type variations, serotype variations, and the structural or “surface inheritance” of ciliary structures. Remarkably, microsurgical changes to the ciliary structures on the surface of Paramecium cells are inherited by offspring. The stability of induced characters once the stimulus was removed (called “cellular memory”) and the number of generations characters were maintained varied widely.However, the results indicated that long-term stability and heritability need not be the result of changes to the DNA sequence (Nanney 1958).During the 1950s to 1970s a growing set of observations indicated that determined and differentiated states of cells are transmitted in cell lineages. These observations concerned studies of Drosophila imaginal discs by Ernst Hadorn; Briggs and King’s cloning experiments with amphibians; Mary Lyon’s work on X-chromosome inactivation; and work establishing the in vitro clonal stability of cultured cell lines. Eventually, the term epigenetic inheritance came to refer to hereditary variation that does not involve changes to the DNA sequence.The brief account of some of the early work on unicellular organisms given above illustrates some。

dissertation limitation 的句

dissertation limitation 的句1. One limitation of the study was the small sample size, which may limit the generalizability of the findings to a larger population.2. Another limitation was the reliance on self-report measures, which might introduce bias or inaccuracies in the data collected.3. The study was also limited by the restricted timeframe in which data was collected, which may not fully capture any long-term effects or changes.4. The use of a single research method, such as surveys, limited the ability to gather more in-depth or comprehensive data on the research topic.5. The study was conducted in a specific geographic area, which may limit the applicability of the findings to other regions or cultures.6. The research participants were predominantly from a specific age group, which may restrict the generalizability of the findings to other age groups.7. Ethical considerations, such as privacy concerns or limitations in consent procedures, may have influenced the data collection methods and subsequently impacted the study's results.8. The study relied on secondary data sources, which may have limitations in terms of data accuracy or relevance to the research objectives.9. The study was constrained by budgetary limitations, which may have affected the scope and extent of the research conducted. 10. The study did not consider potential confounding variables, which may limit the ability to establish causal relationships between variables of interest.。

高考冲刺2024年高考英语真题重组卷01(考试版)

冲刺2024年高考英语真题重组卷（上海专用）真题重组卷01I.Listening prehension （第110题, 每题1分；第1120题，每题1.5分；共25分）Section ADirections: In Section A, you will hear ten short conversations between two speakers. At the end of each conversation, a question will be asked about what was said. The conversations and the questions will be spoken only once. After you hear a conversation and the question about it, read the four possible answers on your paper, and decide which one is the best answer to the question you have heard.1. A By the shuttle bus B. By a friend's private carC By the subway D. By a shared bike.2、A. Academic problems. B. The man's university tourC. A Weekend travel planD. The man's tour to a lake3. A. The lady will go hiking next weekB. The lady took her kitten to the clinic last weekC. The man cares about the woman.D. The man didn't go hiking last week.4. A. He wants to travel to Shanghai.B. He has found a suitable job.C. He graduated last month.D. His hometown may be Nantong5. A. Silent B.Crazy C.Relieved. D. Depressed6. A. He wants the house to have a garage and a garden.B.He just wants a space to sunbathe in his house.C.He wants to buy a villa.D.He likes European style decoration7. A. He is crazy about readingB. He likes the decoration style of the libraryC. He is a knowledgeable college studentD. He is a librarian8. A. She likes similar car models.B. She promised a refund within a weekC. She encouraged the man to buy the model carD She has sold a lot of cars9. A.He wants to leave the panyB. He is the project leader of the panyC. He thinks their hard work will be wastedD.He will announce the progress of the project10. A. His child came home late and had no foodB. He has spared some food for his child.C.The whole family waited the child came back for dinnerD. He was very angry with his child's behavior.Section BDirections: In Section B, you will hear two passages and passage or conversation, you will be asked several questions will be read twice, but the question will be spoken only one the four possible answers on your paper and decide which o you have heard.Questions 11 through 13 are based on the following passage11.A. Negative effects of eating too many snacksB. The differences between snacks and meals.C. Strategies of avoiding eating too many snacks before meals.D. Healthy ways of having meals.12. A Avoid eating things between meals.B. Eat as much fruit as possible.C. Eat food like toast shortly before dinner to help with digestion.D. Have a cup of yogurt in the afternoon.13.A. To control the amount of snacks you eatB. To make it healthier.C. To help you focus on the main eventD. To help you know what exactly you are eatingQuestions 14 through 16 are based on the following passage.14. A. 3,000 billion trees. B. 400 billion trees.C.50 million trees.D. 15 billion trees.15.A.Russia has always ranked first in the number of trees.B.Trees would be gone in the future at current removal rate.C.People will plant trees on the cultivated land.D.It is impossible to calculate the total number of trees16. A. To stop people from building houses endlessly.B.To draw people's attention to the importance of trees.C.To call on people to protect the homes of wild animals.D.To attract people to study the growth environment of treesQuestions 17 through 20 are based on the following conversation.17. A. Personal travel plan. B. TravelC. Party dress.D. Organization of work18. A. Jerry will travel by highspeed railB. Jerry is Helen's cousin.C. Jerry's parents live in NanjingD. Jerry is resting in his apartment now19. A. She knows the boss thereB. She booked the table a month earlier.C. Her friend works in this restaurantD. She has a noble status.20. A. Going for a picnic in the forest park.B. Resting in the apartment.C. Going to the Domingo restaurant for dinner.D. Going to Shanghai MuseumII.Grammar and Vocabulary （每题1分；共20分）Section ADirections: After reading the passage below, fill in the blanks to make the passage coherent and grammaticallycorrect. For the blanks with a given word, fill in each blank with the proper form of the given word; for the other blanks, use one word that best fits each blank.（2023年1月上海春季高考）Young EnterpriseYoung Enterprise is an organization that makes serious efforts to teach all types of young people the general principles of running a business(21) __________( originate ) in the United States of America, the idea of Young Enterprise was introduced into Britain by a successful banker.(22)__________ it developed slowly in its early years, the organization grew rapidly later. Young Enterprise is now backed by industry and merce, so that today young people throughout the United Kingdom can participate.A participant in Young Enterprise is known as an Achiever. Young Enterprise primarily meets the needs of young people ( 23 )__________ are still at school, giving them an understanding of industry and the opportunities it may offer them in the future. But it is usually possible (24 )__________ ( include ) young people in the same age group who have left school but have not yet started work.An Adviser is a practicing business executive (管理人员) with an expert knowledge of his own field who volunteers to keep a Young Enterprise pany during its trading year.(25)__________counts for Advisers is an ability to get on with young people and to put across the subject. As the name(26)__________ (imply), Advisers are there to advise: they do not run the panies.Normally, three Advisersone on accountancy, one on production and one on marketing,(27)__________ ( be ) available to each pany. Young Enterprise makes (28)__________ a rule that the Advisers must e from a variety of business occupations.A Sponsor,(29)__________ (reward) only by the success of the enterprise of "its" Achievers, is an organization which participates in Young Enterprise and,(30 )__________ its own expense, provides facilities by making available munications,advice and encouragement.Section B（2021年上海春季高考）Directions: Fill in each blank with a proper word chosen from the box. Each word can be used only once. Note that there is one word more than you need.The nature is part of us. Therefore , it holds a mysterious ( 31 )__________for me. In my memory , the valley was quiet and calm, only to see the wheat all over the mountains waving together in rhythm when the wind blew through, like a ballet troupe. The sun rose every morning as usual, sweeping across the valley and ultimately falling behind the peaks. The snow that falls in winter always melts in spring, bringing new hope to this nature where everything was pleasant and beautiful.Led by fate , I have became an environmentalist and had the honor of being invited to address students about my green lifestyle for a long time. The students were surprised at my lifestyle and maybe they thought my lifestyle was no longer suitable for modern life.Fortunately , they were still listened to whole lecture , saluting or ( 32 )_________ meto some extent the applause implied their encouragement to me. s I began to interact with them under the stage, I was (33 )__________by kids' lack of knowledge of nature so that they had little knowledge of protecting environment.After the address, I put up a stand in the ( 34 )__________offering green food , hoping them interested in it to get the ( 35 )____________experiencing a firsthand feeling of the green lifestyle no one shows any interest in. So I decided to team up with the concert (36)__________to run a campaign: “anyone who can answer a( n)(37)__________ environmental question is qualified to attend the concert. Soon the music can(38 )___________them ing here”.Since then , I have been considering why kids today do not have the same deep appreciation for nature that I do. One of the significant factors may be that the former rural civilization has been replaced by the urban civilization. In the past, the poor played the ( 39 )_________role in the nature , so they cleared the wasteland, planted crops and reproduced civilization. With the massive invasion of industrialization and urbanization, people were forced to move away from nature. The struggle between tradition and modernity , the confrontation between humans and nature has led people to believe that they are the masters of the universe. Is this really the case? It is time to think about who ( 40 )_________ us to destroy nature.III.Reading prehension (共45分。

威廉姆深交易成本经济学

3.Transaction Cost EconomicsOLIVER E.WILLIAMSONTransaction cost economics is an effort to better understand complex economic organization by selectively joining law,economics,and organization theory. As against neoclassical economics,which is predominantly concerned with price and output,relies extensively on marginal analysis,and describes theﬁrm as a production function(which is a technological construction),transaction cost economics(TCE)is concerned with the allocation of economic activity across alternative modes of organization(markets,ﬁrms,bureaus,etc.),employs discrete structural analysis,and describes theﬁrm as a governance structure (which is an organizational construction).Real differences notwithstanding, orthodoxy and TCE are in many ways complements—one being more well-suited to aggregation in the context of simple market exchange,the other being more well-suited to the microanalytics of complex contracting and nonmarket organization.I begin by contrasting the lens of contract(out of which TCE works)with the lens of choice(orthodoxy).Vertical integration,which is the paradigm prob-lem for TCE,is then examined.The operationalization of TCE is discussed in Section3.Variations on a theme are sketched in Section4.Public policy is discussed in Section5.Concluding remarks follow.1.T HE L ENSES OF C HOICE AND C ONTRACT1Big IdeasHal Varian has recently distinguished between important ideas and Big Ideas and describes Ronald Coase’s classic paper,“The Nature of the Firm”(1937)as a Big Idea(2002,p.C2).Although there is widespread agreement on this,the nature of the big idea took a long time to register.Thus as of1972,thirty-ﬁve years after the publication of“The Nature of the Firm,”Coase described his 1937article as“much cited and little used”(1972,p.63).It was much cited because it was onto something important,perhaps even big.But it was little used because the big idea was only dimly perceived and/or lacked operationalization (Coase,1992,pp.716–718).1This subsection is based on Williamson(2002b).41C.M´e nard and M.M.Shirley(eds.),Handbook of New Institutional Economics,41–65.C 2005Springer.Printed in the Netherlands.42Oliver E.WilliamsonThe essence of the Coasian contribution has been variously described (Williamson,1994,p.202;North,2000,p.37;Werin,2000,p.45).For the purposes of TCE,I contend that the overarching big idea was to move from choice to contract:bring the lens of contract systematically to bear on economic phenomena of all kinds.For many transactions,of which the make-or-buy decision is one(Coase,1937),the contractual structure is easily recog-nized.Other transactions,such as the externality problem(Coase,1960),needed to be reformulated to bring out their latent contractual features.The object,in these and other cases described herein,is to uncover previously neglected but, often,consequential features,the discovery of which often leads to different and, sometimes,deeper understandings than the orthodox lens of choice affords.If, as James Buchanan declares,“mutuality of advantage from voluntary exchange is...the most fundamental of all understandings in economics”(2001,p.29), then at least some of us should be thinking of economics as the“science of exchanges”(Buchanan,2001,p.28).2The Sciences of Choice and ContractEconomics throughout the20th century has been developed predominantly as a science of choice.As Lionel Robbins famously put it in his book, The Nature and Signiﬁcance of Economic Science,“Economics is the science which studies human behavior as a relationship between ends and scarce means which have alternative uses”(1932,p.16).Choice has been developed in two parallel constructions:the theory of consumer behavior,in which consumers maximize utility,and the theory of theﬁrm as a production function,in which ﬁrms maximize proﬁt.Economists who work out of such setups emphasize how quantities are inﬂuenced by changes in relative prices and available resources,a project which became the“dominant paradigm”for economics throughout the twentieth century(Reder,1999,p.48).But the science of choice is not the only lens for studying complex economic phenomena,nor is it always the most instructive lens.The other main but less fully developed approach is the science of contract.Indeed,Buchanan(1975, p.225)avers that economics as a discipline went“wrong”in its preoccupation with the science of choice and the optimization apparatus associated therewith. What was needed was the parallel development of a science of contract.Awaiting this,some phenomena would go unnoticed,others would be poorly understood, and public policy error would result.2Students of the history of thought will remind us that catallactics—meaning“the science of exchanges”—has much earlier origins.Indeed,a book by E.B.de Condillac on this subject was published in1776,which is when The Wealth of Nationsﬁrst appeared(see Murray Rothbard(1987,pp.377–378) for an historical sketch).Recurrent interest in the science of contract notwithstanding,it has operated in the shadows of the science of choice.Why the disparity?Here as elsewhere,good ideas need to be operationalized.Contractual analysis has gotten under way in a sustained way only during the past 40years.Transaction Cost Economics43 As perceived by Buchanan,the principal needs for a science of contract were to theﬁeld of publicﬁnance and took the form of public ordering:“Pol-itics is a structure of complex exchange among individuals,a structure within which persons seek to secure collectively their own privately deﬁned objec-tives that cannot be efﬁciently secured through simple market exchanges”(1987, p.296;emphasis added).Thinking contractually in the public ordering domain leads into a focus on the rules of the game.Issues of a constitutional eco-nomics kind are posed(Buchanan and Tullock,1962;Brennan and Buchanan, 1985).Whatever the rules of the game,the lens of contract is also usefully brought to bear on the play of the game.This latter is what I refer to as private ordering, which entails self-help efforts by the immediate parties to a transaction to align incentives and craft governance structures that are better attuned to their ex-change needs.John mons’prescient statement on the nature of the economic problem provides the unifying theme:“the ultimate unit of activ-ity...must contain in itself the three principles of conﬂict,mutuality,and order. This unit is the transaction”(1932,p.4).3Not only does transaction cost eco-nomics take the transaction to be the basic unit of analysis,but governance is the means by which to infuse order,thereby to mitigate conﬂict and realize mutual gain.Although market competition serves these governance purposes in the context of the“simple market exchanges”to which Buchanan made reference(which is wholly in the spirit of orthodox price theory),transaction cost economics is predominantly concerned with complex market exchange where there are small numbers of parties on each side of the transaction.Rather than examine such issues with the price-theoretic apparatus of oligopoly or oligopsony,transac-tion cost economics focuses instead on uncovering and explicating the strategic hazards that are posed by small numbers exchange in the context of incom-plete contracting and the cost-effective deployment of governance to mitigate these hazards.Strategic issues that had been ignored by neoclassical economists from1870to1970now make their appearance(Makowski and Ostroy,2001, pp.482–483,490–491).Figure1sets out the main distinctions.The initial divide is between the sci-ence of choice(orthodoxy)and the science of contract.The latter then divides into public(constitutional economics)and private ordering parts,where the second is split into two related branches.One branch deals with ex ante incen-tive alignment(mechanism design,agency theory,the formal property rights literature)while the second features the ex post governance of contractual 3Not everyone associated with the lens of contract would agree.Coase,for example,contends that “American institutionalism,”of which Commons was a prominent part,“is a dreary subject...All it had was a stance of hostility to the standard economic theory.It certainly led to nothing”(1984,pp.229–230). My view is that Commons was ahead of his time.He had a lens of contract conception of economics as early as the1920s.44Oliver E.WilliamsonFigure1.The sciences of choice and contractrelations(contract implementation).Albeit related,these two are in tension. Thus whereas transaction cost economics locates the main analytical action in the ex post stage of contract(where maladaptation problems appear),the formal incentive alignment literature annihilates ex post governance.4One device for accomplishing this is to assume common knowledge of payoffs and costless bargaining.The use of strong assumptions(of which common knowledge of payoffs and costless bargaining are two)to strip away inessentials and get at the essence is,to be sure,vital to the scientiﬁc enterprise.Simpliﬁcations,however,that lose contact with core issues are deeply problematic:“A model can be right in...[a]mechanical sense...[yet be]unenlightening because...[it is]imper-fectly suited to the subject matter.It can obscure the key interactions,instead of spotlighting them”(Solow,2001,p.112).In the degree to which the core issues that are posed by contractual incompleteness are those of maladaptation, 4Contract theorists who concentrate the analytical action on the ex ante incentive alignment stage of contracting might complain that TCE makes strong assumptions also,the effect of which is to annihilate the ex ante incentive alignment stage.For example,TCE assumes that contracting parties in intermediate product markets are risk neutral,whence efﬁcient risk bearing plays no role in incentive alignment.Contract theorists who rely on risk aversion for their main results might protest against risk neutrality.Be that as it may,TCE also assumes that contracting parties look ahead,recognize consequential con-tractual hazards that arise during contract implementation,and factor these into the ex ante contractual design—by pricing out unrelieved contractual hazards and by introducing credible commitments(in cost effective degree)—so ex ante and ex post stages of contract are deﬁnitely joined.What TCE disallows are assumptions which vaporize maladaptation and strategizing during contract implementation—of which common knowledge of payoffs and costless bargaining are two.Transaction Cost Economics45 formalizations that preserve rather than annihilate ex post governance are needed (Bajari and Tadelis,2001).2.T HE P ARADIGM P ROBLEM:V ERTICAL I NTEGRATION Contract is an encompassing concept.Rather than treat the issue in its full generality,it will be instructive to begin with a speciﬁc puzzle of economic organization,ideally one for which other contractual issues will turn out to be variations on a theme.The obvious transaction with which to begin is that of vertical integration, or,in more mundane terms,the make-or-buy decision.Not only is the make-or-buy decision the transaction on which Coase focused in1937,but it has a prior and continuing history of importance within economics.Examining the intermediate product market transactions(within and betweenﬁrms)also has an advantage in that it relieves many of the asymmetry conditions—of information, budget,legal talent,risk aversion,and the like—that complicate the analysis of transactions inﬁnal product markets.5Coase’s classic article opens with a basic puzzle:Why does aﬁrm emerge at all in a specialized exchange economy?If the answer resides in entrepreneurship, why is coordination“the work of the price mechanism in one case and the entrepreneur in the other”(Coase,1937,p.389)?Coase appealed to transaction cost economizing as the hitherto missing factor for explaining why markets were used in some cases and hierarchy in other cases and averred that“The main reason why it is proﬁtable to establish aﬁrm would seem to be that there is a cost of using the price mechanism,the most obvious...[being]that of discovering what the relevant prices are”(1937,p.391).That sounds plausible, but is it truly comparative?How is it that internal procurement by theﬁrm avoids the cost of price discovery?The“obvious”answer is that sole-source internal supply avoids the need to consult the market about prices because internal accounting prices of a formulaic kind(say,of a cost-plus kind)can be used to transfer a good or service from one internal stage to another.If,however,that is the source of the advantage of internal organization over market procurement,the obvious lesson is to apply this same practice to outside procurement.Theﬁrm simply advises its purchasing ofﬁce to turn a blind eye to the market by placing orders,period by period,with a qualiﬁed sole-source external supplier who agrees to sell on cost-plus terms.In 5Final product market transactions and transactions between suppliers and distributors need to be dis-tinguished.The former refer to transactions betweenﬁrms(as suppliers)andﬁnal consumers(buyers). Serious asymmetry conditions for which consumer protections are sometimes warranted arise forﬁnal product market transactions.By contrast,the transactions between the manufacturer and the distributor are betweenﬁrms.Thus the manufacturer can sell outright to distributors(which is a market transaction).Or the manufacturer can integrate forward into distribution(so both stages are under uniﬁed ownership/hierarchy). Or the manufacturer can create franchisees(which are a hybrid mode of contracting).46Oliver E.Williamsonthat event,ﬁrm and market are put on a parity in price discovery respects—which is to say that the price discovery burden that Coase ascribes to the market does not survive comparative institutional scrutiny.Even,however,if price discovery did survive comparative institutional scrutiny,that seems to be a thin basis upon which to rest the case for using ﬁrms rather than markets if,as I contend,ﬁrm and market differ in kind rather than in degree.What economic purposes are served by the discrete structural changes that distinguish market and hierarchy?Does the move from choice (where prices are focal)to contract implicate other,possibly more basic,con-siderations?What rudiments inform the logic of contract and comparative eco-nomic organization?3.T HE R UDIMENTSThis last invites the student of economic organization to step back and address contract“on its own terms.”What are the attributes of human actors that bear on the efﬁcacy of contract?What unit of analysis should be employed?Of the many purposes of contract,which are salient?How are alternative modes of governance described?What refutable implications accrue upon reformulating the problem of economic organization in comparative contractual terms?Are the data corroborative?What are the public policy ramiﬁcations?(a)Human ActorsIf“Nothing is more fundamental in setting our research agenda and informing our research methods than our view of the nature of the human beings whose be-havior we are studying”(Simon,1985,p.303),then economists and other social scientists are well-advised to describe the key cognitive,self-interest,and other attributes of human actors on which their analyses rest.Simon’s view of cog-nition is that the usual hyperrationality assumption be supplanted by bounded rationality—behavior that is“intendedly rational but only limitedly so”(1957a, p.xxiv).He further recommends that self-interest be described as“frailty of mo-tive”(1985,p.305).TCE concurs that bounded rationality is the appropriate cog-nitive assumption and takes the chief lesson of bounded rationality for the study of contract to be that all complex contracts are unavoidably incomplete.But TCE also takes a further step,which takes exception with the common view that bounded rationality implies that human actors are myopic.As against myopia, human actors are assumed to have the capacity to look ahead,uncover possible contractual hazards,and work out the contractual ramiﬁcations(Shultz,1995).TCE also pushes beyond frailty of motive to make provision for opportunism. This latter does not deny that most people will do what they say and some will do more most of the time.Opportunism,however,has reference to exceptions—outliers where there is a lot at stake and parties are often observed to defect from the spirit of cooperation to insist on the letter of the incomplete contract. Strategic considerations are introduced upon making provision for opportunism.Transaction Cost Economics47(b)Unit of AnalysisThe natural unit of analysis for lens of contract purposes is the transaction. Naming a unit of analysis is always much easier,however,than identifying the critical dimensions for describing the unit of analysis—as witness the fact that the key attributes for so many would-be units of analysis are never identiﬁed.6 Awaiting dimensionalization,transaction cost economics remained a largely tautological construction.To be sure,transactions can be variously described—depending on the pur-pose.Transaction cost economics holds that three dimensions that have perva-sive ramiﬁcations for governance are asset speciﬁcity(which takes a variety of forms—physical,human,site,dedicated,brand name—and is a measure of nonredeployability),the disturbances to which transactions are subject(and to which potential maladaptations accrue),and the frequency with which transac-tions recur(which bears both on the efﬁcacy of reputation effects in the market and the incentive to incur the cost of specialized internal governance).The ab-sence of asset speciﬁcity describes the ideal transaction in law and economics for which competition works well:“sharp in by clear agreement;sharp out by clear performance”(Macneil,1973,p.734).As asset speciﬁcity builds up,how-ever,bilateral dependency develops and,in combination with uncertainty(which pushes incomplete contracts out of alignment),the aforementioned contractual complications set in.(c)Main PurposeInterestingly,both the economist Friedrich Hayek(1945)and the organization theorist Chester Barnard(1938)were in agreement that adaptation is the central problem of economic organization.Hayek(pp.526–527)focused on the adap-tations of economic actors who adjust spontaneously to changes in the market, mainly as signaled by changes in relative prices:Upon looking“at the price system as...a mechanism for communicating information,”the marvel of the market resides in“how little the individual participants need to know to be able to take the right action.”By contrast,Barnard featured coordinated adaptation among economic actors working through administration(hierarchy).The latter is accomplished not spontaneously but in a“conscious,deliberate,purposeful”way(p.9)and comes into play when the simple market exchanges on which Hayek focused break down.In effect,the adaptations to which Hayek refers are autonomous adapta-tions in which individual parties respond to market opportunities as signaled by changes in relative prices whereas the adaptations of concern to Barnard are cooperative adaptations accomplished through administration within theﬁrm. 6Examples of would-be units of analysis for which operational content is missing include the role(see Simon’s critique(1957a,p.xxx),the decision-premise(which is Simon’s candidate,but which has found little application outside of cognitive psychology(Newell and Simon,1972)),and the routine(Nelson and Winter,1982).The next two paragraphs and Section4are based on Williamson(2002a).48Oliver E.WilliamsonBecause a high performance economic system will display adaptive capacities of both kinds,an understanding and appreciation for both markets and hierarchies (rather than the comparative economic systems dichotomy between markets or hierarchies)is needed.Theﬁrm for these purposes is described not as a produc-tion function(which is a technological construction)but as a governance struc-ture(which is an organizational construction).And the market is described simi-larly.The lens of contract,as against the lens of choice,is made the cutting edge.One of the advantages of focusing on adaptation as the main case is that it brings added meaning to the idea of mutual gain.It is elementary that gains from trade will always be realized by moving onto the contract curve.But how is this to be accomplished in a world where complex contracts are incom-plete and are implemented over time in the face of disturbances for which contingent provisions either have not been made or,if made,are often in error?Crafting governance structures that are attuned to the hazards and help the parties to restore efﬁciency(return to the shifting contract curve)where oth-erwise a costly impasse would develop is needed in these circumstances.More attention to designing processes that have good adaptive properties(and less to concentrating all of the action in the ex ante incentive alignment stage)is thus one of the central lessons of TCE.(d)Governance StructuresExamining economic organization through the lens of contract both places the spotlight on ex post adaptation and,in the process,gives prominence to the role of governance.Speciﬁcally,TCE holds that each generic mode of governance is deﬁned by a syndrome of internally consistent attributes to which different adaptive strengths and weaknesses accrue.The three attributes of principal importance for describing governance struc-tures are(1)incentive intensity,(2)administrative controls,and(3)contract law regime.Spot markets and hierarchy differ with respect to these attributes as fol-lows:the high-powered incentives of markets are supplanted by low-powered incentives when transactions are organized withinﬁrms;market exchange is a hands-off control mechanism whereas hierarchy involves considerable hands-on administrative involvement;and whereas disputes in markets are treated in a legalistic way and rely on court ordering,courts refuse to hear(most)in-ternal disputes,whereupon theﬁrm becomes its own court of ultimate appeal. Firms have access toﬁat that markets do not because of these dispute resolution differences.7Governance,moreover,is an encompassing concept.Going beyond polar forms,all modes of organization within which(or with the support of which)7One of the reasons why markets lackﬁat is that attempts to award decision rights to autonomous agents by contract(e.g.,A will decide disputed matters of type X;B will decided disputed matters of type Y;etc.) are commonly unenforceable.That is because one of the parties to a market contract can invoke(invent)a “technicality,”the effect of which is to bring the dispute before the courts.Transaction Cost Economics49 Table1.Attributes of leading generic modes of governanceGovernance ModesGovernanceAttributes market hybrid hierarchyincentives high-powered less high-powered low-poweredadministrative nil some muchsupport bybureaucracycontract law legalistic contract asﬁrm as own courtregime framework of ultimate appeal(ﬁat)transactions are managed come under scrutiny.Hybrid modes of contracting to which credible commitment supports have been crafted(penalties against premature termination,specialized dispute settlement mechanisms and the like) are especially important.Table1summarizes the key attributes of(spot)market, hybrids,and hierarchies.As developed in the text accompanying Figures2and 3below,the clusters of attributes that deﬁne these three alternative modes ofFigure2.Transaction costs and asset speciﬁcity50Oliver E.WilliamsonFigure3.Simple contracting schemagovernance give rise to differential transaction costs among modes,conditional on the attributes of the transactions to be organized.An unremarked governance complication also needs to be introduced.This is that organization,like the law,has a life of its own(Selznick,1950,p.10). Issues of internal organization that have been featured by organization theorists (Barnard,1938;Simon,1947;March and Simon,1958)and by sociologists (Michels,1912;Merton,1936;Selznick,1949;Scott,1992)thus arise.Note in this connection that while it is relatively easy to show that internal orga-nization is subject to incentive limits and bureaucratic distortions,it is much more difﬁcult to show that comparative cost consequences accrue upon taking a transaction out of the market and organizing it internally(Williamson,1985, Chap.6).That is because the goods and services traded in a market are produced withinﬁrms.The question of make-or-buy is thus whether the costs(including bureaucratic costs)are greater in two autonomousﬁrms than in one combined entity.TCE uncovers and explicates the incentive and bureaucratic cost conse-quences that attend the move from market to hierarchy by postulating two processes:replication and selective intervention.Were it that theﬁrm could replicate the market in all circumstances where market procurement works well and intervene selectively(if expected net gains can be projected)where mar-kets break down,then theﬁrm could never do worse than the market(through replication)and would sometimes do better(through selective intervention).As it turns out,it is impossible to realize this ambition.Incentives are unavoidablyTransaction Cost Economics51 compromised8and added bureaucratic cots are unavoidably incurred upon tak-ing a transaction out of the market and organizing it internally.The upshot is that the move from market to hierarchy is attended by tradeoffs.Discriminating alignment is thus needed.(e)Predictions and Empirical TestingThe main engine from which the predictions of TCE are derived is that of discriminating alignment,according to which transactions,which differ in their attributes,are aligned with governance structures,which differ in their cost and (adaptive)competence,so as to effect a transaction cost economizing result.The upshot is that there is a place for each generic mode of governance,yet each should be kept in its place.The TCE answer to the Coasian puzzle of which transactions go where and why resides precisely in discriminating alignment, the efﬁcacy of which relies in part on weak-form natural selection(Simon,1983, p.69)to penalize errors of inefﬁcient alignment.It will be convenient here to focus on three modes:spot markets(M),hybrid modes of contracting(X),into which credible commitments have been intro-duced,and hierarchies(H).The basic argument is that(1)markets are well-suited to making autonomous adaptations,ﬁrms enjoy the advantage for comparative adaptation purposes,and hybrids are located in between,(2)the needs for adap-tation vary among transactions(especially with reference to asset speciﬁcity), and(3)bureaucratic cost burdens increase as transactions move from market, to hybrid,to hierarchy.In a heuristic way,the transaction cost consequences of organizing transac-tions in markets(M)and hierarchies(H)as a function of asset speciﬁcity(k) are shown in Figure2.As shown,the bureaucratic burdens of hierarchy place it at an initial disadvantage(k=0),but the cost differences between M(k)and H(k)narrow as asset speciﬁcity builds up and eventually reverse as the need for cooperative adaptation becomes especially great(k 0).As indicated,more-over,the hybrid mode of organization X(k),is viewed as a market-preserving credible contracting mode that possesses adaptive attributes located between classical markets and hierarchies.Incentive intensity and administrative control thus take on intermediate values and Karl Llewellyn’s(1931)concept of contract 8The issues here are rather involved.The interested reader is referred to Williamson(1985,Chap.6) for a discussion.Brieﬂy the argument is that(1)replication is essential if parity betweenﬁrm and market is to be assumed,(2)such replication implies that incentives are unchanged in each of the separable stages upon taking a transaction out of the market and organizing it internally,yet(3)unchanged incentive intensity cannot be accomplished if the acquiring stage exercises control over the accounting system(to include transfer prices,overhead rates,depreciation,and the like)and cannot credibly commit to behaving nonstrategically,to include intervening always but only for good cause(selective intervention).But there is more.Not only is incentive intensity unavoidably weakened when transactions move from market to hierarchy,but cooperative adaptation across successive stages is promoted by intentionally weakening incentive intensity within theﬁrm.。

discarded-qualifiers

discarded-qualifiersDiscarded QualifiersIn academic research, one important aspect is the selection of appropriate qualifiers to ensure the accuracy and reliability of the study. Qualifiers refer to specific conditions or characteristics that are used to define the scope or limitations of the research findings. However, not all qualifiers are suitable for inclusion in a study, and some may need to be discarded. In this article, we will explore the reasons why qualifiers may be discarded and the implications of such actions.1. Lack of relevanceOne common reason for discarding qualifiers is their lack of relevance to the research topic. Qualifiers should be carefully chosen to ensure that they contribute to the understanding and interpretation of the research findings. If a qualifier does not provide any meaningful insights or information, it may be deemed irrelevant and discarded. Researchers need to focus on qualifiers that have a direct impact on the study objectives and findings.2. Ambiguity or subjectivityQualifiers that introduce ambiguity or subjectivity into the research findings should also be discarded. The goal of academic research is to generate reliable and objective knowledge. Qualifiers that introduce personal opinions, biases, or vague conditions can undermine the credibility of the study. Researchers should strive for clarity and precision in their qualifiers, avoiding any language that may lead to misinterpretation or confusion.3. Inconsistency with research methodologyEvery research study follows a specific methodology that guides the collection and analysis of data. Qualifiers that deviate from the chosen methodology may need to be discarded. For instance, if a study adopts a quantitative approach, qualifiers based on qualitative data may not be appropriate and should be excluded. Consistency between qualifiers and research methodology is crucial to maintain the integrity and validity of the study.4. Lack of empirical evidenceQualifiers should be supported by empirical evidence whenever possible. If a qualifier is based solely on theoretical assumptions or lacks empirical data tosubstantiate its validity, it may be discarded. Researchers need to ensure that their qualifiers are grounded in evidence and can withstand scrutiny by the academic community. Without empirical support, qualifiers may be seen as speculative or unsubstantiated.5. Overgeneralization or oversimplificationQualifiers that lead to overgeneralization or oversimplification of the research findings should be carefully evaluated and potentially discarded. While qualifiers can help define the scope of a study, they should not be used to draw sweeping conclusions or oversimplify complex phenomena. Researchers must exercise caution and avoid using qualifiers that may misrepresent or distort the research findings.In conclusion, the selection of qualifiers in academic research is a crucial step in ensuring the accuracy and reliability of the study. However, not all qualifiers are suitable for inclusion, and some may need to be discarded. Researchers should carefully evaluate the relevance, clarity, consistency, empirical support, and potential for overgeneralization or oversimplification when decidingwhich qualifiers to include in their study. By discarding qualifiers that do not meet these criteria, researchers can enhance the rigor and validity of their research findings.。

The-impact-of-cross-border-mergers-and-acquisitions-on-the-acquirers-R-amp-D-Firm-level-evidence

The impact of cross-border mergers and acquisitions on the acquirers'R&D —Firm-level evidence ☆Joel Stiebale ⁎University of Nottingham,Nottingham University Business School,United KingdomUniversity of Nottingham,Nottingham Centre for Research on Globalisation and Economic Policy (GEP),United Kingdom RWI,Germanya b s t r a c ta r t i c l e i n f o Article history:Received 6October 2011Received in revised form 17April 2013Accepted 23April 2013Available online 6May 2013JEL classi ﬁcation:D21F23G34C31O31O33Keywords:Multinational enterprises Mergers and acquisitions InnovationThis paper provides empirical evidence on the relationship between cross-border acquisitions and innovation activities of the acquirer.For the empirical analysis a unique ﬁrm-level data set is constructed that combines survey data for German ﬁrms with a merger and acquisition database.After a cross-border acquisition,investing ﬁrms display a higher rate of domestic expenditures for research and development.Controlling for endogeneity of foreign acquisitions by estimating a two-equation system with limited dependent vari-ables and applying instrumental variable techniques it is found that part of this correlation stems from a causal effect.The estimated effects are robust towards alternative identi ﬁcation strategies and are higher in industries with high knowledge intensity.The analysis is complemented by an investigation of the effects on tangible investment spending and by a comparison of the effects of cross-border acquisitions to those of green ﬁeld foreign direct investments and domestic acquisitions.©2013Elsevier B.V.All rights reserved.1.IntroductionForeign direct investment (FDI)ﬂows have increased all over the world over the past decades to reach a volume of more than US$1.6trillion in 2011.Much of this increase can be attributed to the ris-ing number of cross-border mergers and acquisitions (M&As).1Fromthe home countries'perspective,cross-border M&As can on the one hand enable market access and the transfer of knowledge from abroad which may strengthen domestic technological capabilities.On the other hand,there might be negative effects if domestic activities are replaced with similar investments abroad.From the host countries'perspective,many policy makers try to prevent foreign takeovers of domestic ﬁrm,especially in knowledge intensive industries.2The global effects of mutual restrictions on cross-border M&As depend on the effects on both the acquirer and the target ﬁrm.Thus,it is important to complement existing knowledge on the effects on inno-vation in target ﬁrms with empirical evidence on the investing ﬁrms.Cross-border acquisitions constitute the main form of FDI in industries with a high R&D intensity (UNCTAD,2007).The effects of international M&As on R&D have important policy implications since innovative activity is regarded as a key factor to spur productivity and growth.Existing empirical evidence on the effects of cross-borderInternational Journal of Industrial Organization 31(2013)307–321☆I would like to thank two anonymous referees and a co-editor for helpful comments and suggestions.Further,I would like to thank the KfW Bankengruppe for hospitality and access to their survey data and Frank Reize for sharing his data preparation ﬁles and his experience with the data set.Helpful comments by Thomas K.Bauer,Dirk Engel,Ingo Geishecker,Christoph M.Schmidt,and Michaela Trax are gratefully ac-knowledged.I would also like to thank seminar participants in Düsseldorf,Göttingen,Kiel,Aachen and Duisburg as well as participants of the 37th conference of the EARIE,the annual meeting of the German Economic Association,2010,and the PhD presenta-tion meeting of the Royal Economic Society 2011for helpful comments and suggestions.⁎University of Nottingham,Nottingham University Business School,Jubilee Campus,South Building,Wollaton Road,Nottingham NG81BB,United Kingdom.Tel.:+441159515093.E-mail address:joel.stiebale@ .1/ReportFolders/reportFolders.aspx?sRF_ActivePath=P,5,27&sRF_Expanded=,P,5,27.2One example is the announced acquisition of the Spanish energy company Endesa by the German energy provider E.ON in the year 2006that was blocked by the Spanish government.Similarly,in 2005,the French government decided to impose restrictions on foreign acquisitions in several strategically important industries with high knowl-edge intensity like information systems andbiotechnology.0167-7187/$–see front matter ©2013Elsevier B.V.All rights reserved./10.1016/j.ijindorg.2013.04.005Contents lists available at SciVerse ScienceDirectInternational Journal of Industrial Organizationj o u r n a l h om e p a g e :ww w.e l s e v i e r.c o m /l o c a t e /i j i oM&As is mostly limited to targetﬁrms,while little is known about the effects on the acquiringﬁrms.3Only recently,cross-border acquisitions as a type of FDI started to receive more attention in the international trade literature.Recent theoretical contributions analyze the role ofﬁrm heterogeneity and different motives that determine the choice of foreign market entry modes(Nocke and Yeaple,2007;Norbäck and Persson,2007).These models argue that international M&As are mainly driven by the desire to acquire complementary assets and technology while greenﬁeld investments(newﬁrms or production units founded by foreign investors)do not provide direct access to foreign knowledge and are rather undertaken to exploit existingﬁrm-speciﬁc assets of the acquiringﬁrm or factor price differences across countries.If comple-mentarities between acquiring and targetﬁrm play a role for cross-border acquisitions and these involve innovative activities it is likely that the effects on domestic R&D are quite different from those of greenﬁeld investments.Hence,it is not possible to derive conclusions about the effects of cross-border M&As from existing studies on greenﬁeld investments or aggregate FDI.It is also likely that the effects of international acquisitions are different from those of domestic transactions since previous research argues that the motives and characteristics of cross-border M&As are different(see Shimizu et al.,2004,for instance).Theory suggests that the characteristics ofﬁrms that self-select into international acquisitions are quite different from those that engage in domestic acquisitions(see e.g.Nocke and Yeaple,2008).Market access–for instance via access to existing networks or market speciﬁc knowledge like marketing capabil-ities–might be a more important motive for international than for do-mestic M&As(see e.g.Nocke and Yeaple,2008;Guadalupe et al.,2012; Blonigen et al.,2012).Improved market access from the perspective of the acquiringﬁrm may increase the incentives to invest in cost reducing or quality enhancing innovations as these can be applied to a larger production output.Further,as efﬁciency differences within an industry are likely to be more pronounced across than within countries(Neary, 2007)it is likely that foreign and domestic acquisition targets have dif-ferent characteristics.This may result in different feedback effects on the investingﬁrm as well.The purpose of this paper is to investigate the impact of cross-border acquisitions on R&D activities of the investingﬁrm.This paper contributes to the existing literature in several aspects.First, empirical evidence on the effects of international acquisitions on innovation activities of the acquirer is sparse.4Further,I contribute to the industrial organization and the international economics litera-ture by comparing the effects of cross-border acquisitions to those of domestic acquisitions and greenﬁeld foreign direct investments. Heterogeneous effects according to industries and target countries with different characteristics are provided.For this purpose a unique ﬁrm-level data set is constructed that combines survey data for Germanﬁrms with balance sheet data and an M&A database.The case of Germany is in particular interesting as it is one of the most technologically advanced countries in the world and is considerably engaged in FDI and global M&As.The empirical framework accounts for unobservedﬁrm heteroge-neity and the possible endogeneity of cross-border acquisitions.The main results are based on a non-linear two-equation model in which the decision to engage in an international acquisition as well as the decision of how much to spend on R&D is explained simulta-neously.Identiﬁcation is achieved by exploiting unexpected shocks to foreign market growth rates and variation in the distance to foreign markets acrossﬁrms.The robustness of the results towards alternative empirical models and identifying assumptions is checked.This paper is organized as follows.In Section2,I summarize the related literature.Section3describes the empirical model and Section4provides a description of the data.Results of the empirical analysis are presented in Section5.Section6concludes.2.Cross-border acquisitions and R&DThis paper is related to several strands of theoretical and empirical literature that look at M&As from the perspective of industrial organi-zation(IO)economics,strategic management,or corporateﬁnance.5 As the M&A literature often does not distinguish explicitly between cross-border and domestic acquisitions or between effects on acquir-ingﬁrms and acquisition targets it is worth taking a look at the litera-ture on international trade and FDI as well.Cross-border acquisition can affect the investingﬁrm's innovation activities through a variety of channels.First,there might be direct effects via relocation of R&D activities.Second,acquisitions may have an impact on other determi-nants of R&D that have been identiﬁed in the theoretical and empirical innovation literature such as aﬁrm's size,market share,competition, technological opportunities,external knowledge sources,market demand,andﬁnancial factors(see,for instance,Cohen and Levine, 1989or Hall and Mairesse,2006for an overview on the determinants of R&D).The main motives for M&As within the IO literature are the strengthening of market power(Kamien and Zang,1990)and the re-alization of efﬁciency gains(Röller et al.,2001).The effects on market power and efﬁciency also belong to the main channels through which M&As can affect R&D.M&As might be undertaken to gain access to targetﬁrms'assets such as production capabilities or intangible assets (e.g.Jovanovic and Rousseau,2008).Efﬁciency gains after an acquisi-tion may,for instance,stem from the diffusion of know-how within the merged entity(Röller et al.,2001)or the reallocation of technol-ogy to more efﬁcient uses(Jovanovic and Rousseau,2008).Synergies resulting from M&As might entail an increase in the efﬁciency of R&D which might increase the incentives to innovate.Regarding the strategic aspect,a reduction in competition has a theoretically ambiguous effect on innovation incentives.This effect depends on market characteristics,the type of innovation,and the de-gree of R&D spillovers(see,for instance,Gilbert,2006;Vives,2008; Schmutzler,2010for a recent discussion).Reduced competition will increase aﬁrm's residual demand–and thus the output to which cost reductions or quality improvements can be applied–but at the same time it tends to decrease the elasticity of demand and thus the impact of price reductions.However,if a merger solely reduces the number ofﬁrms in a market,it is likely that this induces a positive ef-fect on innovation incentives(Vives,2008).Further,the internaliza-tion of technology spillovers that have previously been captured by competitors can also increase the incentives for R&D(Kamien et al., 1992).Gilbert and Newbery(1982)argue thatﬁrms with monopoly power have additional incentives to engage in R&D due to the possibil-ity of preemptive patenting.Acquisitions that are motivated by strategic reasons also play a role in the international economics literature(e.g.Horn and Persson,2001; Neary,2007).Cost differences betweenﬁrms might be more pro-nounced across than within countries and this may increase the incen-tives for cross-border M&As(Bertrand and Zitouna,2006;Bjorvatn, 2004;Neary,2007).In Neary(2007),for instance,cross-border acqui-sitions are accompanied by a reallocation of production from less3The effects of cross-border M&As on targetﬁrms have received considerable atten-tion with respect to productivity(Arnold and Javorcik,2009;Benfratello and Sembenelli,2006)and employment(Almeida,2007).Recently,particular attention has been paid to the effects of foreign acquisitions on innovation activity(Bertrand, 2009;Bertrand et al.,2012;Guadalupe et al.,2012;Stiebale and Reize,2011).4Bertrand and Zuninga(2006)analyze effects of domestic and international M&As on R&D at the industry level.Firm-level studies that analyze differences between ef-fects of domestic and international acquisitions on the acquirers'innovation includeDesyllas and Hughes(2010),Cloodt et al.(2006)and Ahuja and Katila(2001),al-though analyzing effects of cross-border M&As is not at the core of their analysis.5The literature on cross-border M&As from the perspective of the management lit-erature is surveyed in Shimizu et al.(2004).308J.Stiebale/International Journal of Industrial Organization31(2013)307–321efﬁcient acquisition targets to more efﬁcient foreign investors.If M&As are primarily motivated by efﬁciency differences between ﬁrms across countries we would expect an increase in economic activ-ity in acquiringﬁrms at the expense of targetﬁrms.6The impact of cross-border acquisitions on R&D in acquiringﬁrms can be different from the effects on efﬁciency and the scale of produc-tion.Acquirers might relocate R&D facilities from targetﬁrms to the cor-porate headquarters,but keep production sites running(or vice versa). Manyﬁrms tend to cluster their R&D activities close to their headquar-ters or their main corporate production unit due to the aim of managers to keep track of these activities(Howell,1984).Sanna-Randaccio and Veugelers(2007)show in a theoretical model that centralizing R&D in the home country increases the appropriability of the results of R&D efforts as it prevents knowledge spillovers to foreign competitors in the host country.Centralizing R&D may also avoid costs of coordination and may allow a multinational enterprise to exploit economies of scale in R&D(Kumar,2001).Hence,it is well possible that relocation effects for R&D are more pronounced than for production activities.Cross-border acquisitions are a mode of FDI and thus might in addition be motivated by differences in production costs across countries,the desire to enter foreign markets,or the access to country speciﬁc assets.7In most theoretical trade models incorporatingﬁrm heterogeneity,market access is the most important motive for FDI (for instance,Helpman et al.,2004).This type of market-seeking FDI is usually referred to as horizontal investment.Horizontal FDI might reduce domestic production if it comes along with a substitution of exports.Contrarily,FDI might spur headquarter activities such as marketing activities and R&D as these investments can be applied to a larger production output after a foreign investment(Fors and Svensson,2002).This might in turn increase growth in the acquirers' home country.Vertical FDI in analogy to Head and Ries(2003)is motivated by differences in factor costs across countries.However,the motives for cross-border M&As might be quite different from greenﬁeld investments(even in a monopolistic com-petition framework where they are not driven by strategic aspects). Theoretical trade models with heterogeneousﬁrms that differentiate between the modes of foreign market entry usually argue that green-ﬁeld investments are chosen for FDI motivated by production cost differences(Nocke and Yeaple,2007,2008).In contrast,these models argue that cross-border M&As are aimed to achieve access to comple-mentaryﬁrm-speciﬁc assets of acquisition targets(Nocke and Yeaple, 2008),country-speciﬁc assets(Norbäck and Persson,2007),export networks(Blonigen et al.,2012),or capabilities that are non-mobile across countries(Nocke and Yeaple,2007).8If the exploitation of complementary assets entails innovation activities this might in-crease the returns to these activities and thus spur R&D expenditures.There are,however,also counterarguments regarding the effects of international M&As on acquiringﬁrms'R&D.Cross-border acquisi-tions might come along with a substitution of domestic by foreign activities.There might also be a reduction of duplicate R&D activities after a merger if the overlap between the research projects of acquirer and targetﬁrm is large(Veugelers,2006).Further,M&As may lead to a reduction in the competition in technology markets which may reduce the incentives of mergingﬁrms to engage in R&D activities further(Arrow,1962).There are also some counterarguments which can be derived from theﬁnancial economics and the manage-ment literature.M&As are oftenﬁnanced with a high amount of debt which might raise the costs for raising external funds for R&D and there is empirical evidence that especially after a leveraged buyout targets display declining expenditures for capital(Kaplan,1989) and R&D(Long and Ravenscraft,1993).Further,M&As might also arise out of a manager's utility maximization(Shleifer and Vishny, 1988)who wants a large empire under control and conducts M&As at the expense of other investment projects including R&D activities. Finally,M&As might reduce R&D due to increased organizational complexity and tighterﬁnancial controls(Hitt and Hoskisson,1990; Hitt et al.,1991)or due to a disruption of established routines (Ahuja and Katila,2001).Hence,from a theoretical point of view the relationship between foreign acquisitions and acquirers'R&D is unclear and thus boils down to an empirical matter.Empirical studies that deal with the effects of domestic M&As(or do not explicitly differentiate between domestic and international M&As)ﬁnd in the majority negative effects(Cassiman et al.,2005).But the results seem to depend on product and technology market characteristics.Cassiman et al. (2005)argue that the impact of M&As on R&D in the merged entity depends on technological and market relatedness between acquirer and target.They suggest that M&As between rivalﬁrms lead to an overall reduction of R&D efforts,while they predict the opposite when the merged entities are technologically complementary. Studies that deal with the effects on innovation activities in foreign acquisition targets have so far yielded mixed results.For instance, Guadalupe et al.(2012)and Bertrand(2009)ﬁnd positive effects of foreign acquisitions on innovation,while Stiebale and Reize(2011)ﬁnd large negative effects once endogeneity and selection bias are taken into account,and Bertrand and Zuninga(2006)ﬁnd no signiﬁ-cant effect on average but some positive effects in industries with a medium technological intensity.Existing empirical studies that ana-lyze the impact of cross-border acquisitions on innovation activities at theﬁrm level are mostly limited to the evidence on the impact on targetﬁrms.9Marin and Alvarez(2009)ﬁnd that acquisitions undertaken by foreign ownedﬁrms in Spain have a negative impact on the acquirers'innovation activities,in contrast to acquisitions by domestically ownedﬁrms,but they do not analyze the impact of cross-border acquisitions.Ahuja and Katila(2001)as well as Cloodt et al.(2006)analyze differences in a sample of mergingﬁrms according to cultural distance between acquirer and targetﬁrm. Desyllas and Hughes(2010)ﬁnd that cross-border M&As have a more pronounced negative effect on the acquirer's R&D intensity than domestic M&As.3.Empirical strategyTwo main problems have to be addressed in the empirical analy-sis.First,structural zeros arise because a lot ofﬁrms report zero R&D expenditures.Second,endogeneity might arise from the fact that unobserved factors inﬂuencing R&D might also be correlated with a foreign acquisition.Thus,a model that accounts for both structural zeros and endogeneity is speciﬁed to evaluate the impact of international acquisitions on the acquirer's innovation.To evaluate the effect of outward cross-border acquisitions on domestic R&D expenditures,a two-equation model is speciﬁed:RDÃit¼x′itβ1þδIMA itþεitð1Þ6Stiebale and Trax(2011)provide evidence that acquirers'domestic sales and em-ployment tend to increase after international M&As.7See Helpman(2006)for an overview on the theoretical literature onﬁrms and FDI choices.8There are several further possible motives for cross-border acquisitions.In a model of Head and Ries(2008),cross-border acquisitions arise due to the possibility to shift ownership to a more efﬁcient usage.Cross-border acquisitions(and FDI in general) may also be motivated by building an export platform in a tariff free block such as the European Union(Neary,2002).Cross-border and domestic acquisitions may also involve vertical integration.However,while cross-border M&As often take place acrossindustries they are rarely associated with input–output linkages(e.g.,Hijzen et al., 2008).9A detailed discussion about studies that analyze the relationship between foreign ownership and innovation can be found in Stiebale and Reize(2011).309J.Stiebale/International Journal of Industrial Organization31(2013)307–321IMA Ãit ¼x ′it β2þz it γþu it IMA it ¼(1;IMA Ãit >00;elseRD it ¼max RD Ãit ;0ðÞ:ð2ÞThe error terms of the two equations are assumed to be jointly normally distributed:εitu ite N 2ðÞ00 ;σερσερσε1where the variance of u it is normalized to one for identi ﬁcation.RD it denotes the domestic R&D to sales ratio,multiplied by 100,of ﬁrm i in period t .IMA it is a dummy variable that takes the value of one if a ﬁrm acquired a target in an international M&A between t −2and t .An acquisition is de ﬁned as an increase in the ownership share from below to above 50%of equity —either directly or indirectly through a parent or a holding company.x it is a vector of ﬁrm-and industry-level variables that enters both equations.It contains variables that are usually used in innovation studies which are likely to affect both R&D expenditures and interna-tional acquisitions.10A ﬁrm's age is measured in years and serves as a proxy for experience and the stage of the product life cycle.Firm size enters the equations as the logarithm of the number of employees.Human capital intensity is approximated by the share of employees with a university degree.Capital intensity controls for past accumula-tion of tangible assets.The ability to raise equity for ﬁnancing invest-ment is captured by a dummy variable that takes the value of one if the ﬁrm has ﬁnanced part of its tangible investment by equity.Further,a dummy variable for incorporated enterprises is added to the model that captures differences in corporate governance and the ability to raise external ﬁnance.A dummy variable for Eastern Germany accounts for the transition process and regional differences.The model also includes a control variable for foreign ownership.Two dummy variables take the value of one if a ﬁrm cooperates with other ﬁrms or public scienti ﬁc institutions,respectively.11Further,x it contains several variables that account for the competi-tive environment and market conditions.The ﬁrm's lagged domestic market share captures the potential to spread the gain from new or improved products and processes over production output.This variable also accounts for the selection of larger and more productive ﬁrms into foreign markets.The domestic market growth rate -measured at the two-digit level -controls for time-varying changes in market size at the industry level.To account for changes in competition,a further variable measures the net entry rate on the domestic market (see Aghion et al.,2009for an analysis on the effect of entry on innovation).It is also controlled for a ﬁrm's main regional market by a set of dummy variables that take the value of one if a ﬁrm's main market is international,national,or regional,respectively (for instance,Aw et al.,2007,2008analyze the role of exporting for R&D).Industry dummies at the two-digit level control for time invariant product and market characteristics and time dummies capture macroeconomic shocks.z it includes variables that are assumed to affect the propensity to engage in a cross-border acquisition but not domestic R&D expendi-tures.These variables are discussed in detail below.Endogeneity of IMA it ,in the two equation model,stems from a non-zero correlation between the two error terms (ρ≠0).A prerequi-site for logical consistency is that a recursive structure is imposed,i.e.RD it does not appear in Eq.(2)(see e.g.Maddala,1983).This prerequisite ismet in the chosen speci ﬁcation and seems reasonable,as an acquisition in the past on current R&D expenditures is evaluated.The model does not contain ﬁrm-ﬁxed effects.The reason is that introducing ﬁxed effects in non-linear models leads to inconsistent estimates of all parameters.12Estimation is carried out by full maximum likelihood.Full maximum likelihood is more demanding than a two-step control function approach as it requires specifying a joint distribution of the equation system,but it assures most ef ﬁcient estimation if the model is correctly speci ﬁed.13The robustness of the results towards the distributional as-sumptions is checked by using a linear instrumental variable estimator.Standard errors are clustered as some ﬁrms appear more than once in the sample.Irrespective of the estimation procedure,it is necessary for identi ﬁcation that there is at least one valid exclusion restriction,i.e.a variable that affects the probability to engage in a cross-border ac-quisition but not domestic R&D expenditures.In the context of the two equation model,this is a variable that enters z it but not x it .14Two exclusion restrictions are used in the empirical analysis.Score tests are computed to test the joint and individual validity of the two ex-clusion restrictions,and the results of these tests support the model's identifying assumptions.The ﬁrst instrumental variable is the distance to foreign markets which is measured as the minimum distance to Western European countries.This variable captures the well known proximity –concentration tradeoff (see e.g.Brainard,1997):In models of horizontal FDI,ﬁrms face a trade-off between exporting on the one hand and producing locally via FDI on the other hand.The former re-quires them to pay higher transport costs of the goods shipped to the foreign market,but exporters can bene ﬁt from concentrating produc-tion and thereby achieving scale economies.FDI,in contrast,involves paying higher sunk and ﬁxed costs for the af ﬁliate abroad but lower transport costs due to the proximity to consumers.15For this instrument to be valid,it is crucial that omitted regional fac-tors,that are correlated with distance to foreign markets,do not affect R&D expenditures.I argue that most of the systematic differences in inno-vativeness across regions are captured by the control variables,i.e.vari-ables in x it ,like industry dummies,external knowledge sources,and other ﬁrm-and industry-level variables.One might be concerned that ﬁrms choose a certain location because they plan to engage in cross-border acquisitions.However,only a few ﬁrms change their loca-tion after foundation,and the average ﬁrm age at the time of acquisition is more than 35years in our sample.Hence,it seems unlikely that M&As affect the location choice of ﬁrms.10See e.g.Cohen and Levine (1989)and Hall and Mairesse (2006)for an overview on empirical innovation studies.11The survey questions underlying these variables refer to cooperation with ﬁrms and institutions in general and not to cooperation on R&D as in CIS innovation surveys.Hence they do not imply but might affect R&D activities.12A further problem is that many ﬁrms in the data set only appear at most twice in the sample.However,some regressions in ﬁrst differences and with controls for lagged values of the dependent variable on a reduced sample are presented to convey an im-pression about the importance of time-invariant unobserved ﬁrm heterogeneity.13Estimation was carried out in Stata®,version 10.1.The likelihood function of this model can be found in Appendix B available on the web,and the program code for estima-tion is available from the author upon request.Alternative models such as the instrumen-tal variable Tobit model developed by Smith and Blundell (1986)are not applicable as they do not allow for discrete endogenous regressors.Similarly,the fractional response es-timators suggested by Papke and Wooldridge (2008)cannot deal with binary endogenous regressors as well.Abadie (2003)proposes a semi-parametric estimator,but this estima-tor requires that there is a binary instrument variable available which is not the case in this application.Angrist (2001)proposes to use two-stage least squares,but this method is only consistent for censored outcome variables in special cases.Nonetheless,the robust-ness of the main results to using two stage least squares is checked in Section 5.3.14Due to nonlinearity the model is identi ﬁed even without exclusion restrictions,but the results are not very reliable in this case as they critically hinge on distributional and functional form assumptions.15Nonetheless,the relationship between cross-border acquisitions and geographic distance is not unambiguous as this variable might capture other in ﬂuences like cultur-al distance or vertical relations.Hijzen et al.(2008)ﬁnd a negative relation between cross-border M&As and distance,measured at the industry-country level,which is more pronounced for non-horizontal M&As.However,a positive correlation between a ﬁrm's distance to the border and foreign acquisitions does not rule out a negative cor-relation between M&As and distance on a macroeconomic level.Firms may be induced to engage in cross-border acquisitions as opposed to serve a foreign market via exports by distance,but they may (conditional on this choice)choose a close-by target ﬁrm to minimize trade and transaction costs.310J.Stiebale /International Journal of Industrial Organization 31(2013)307–321。

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a r X i v :a s t r o -p h /0502495v 2 17 J u n 2005Mon.Not.R.Astron.Soc.000,1–14(2005)Printed 2February 2008(MN L A T E X style ﬁle v2.2)Dissipationless Mergers of Elliptical Galaxies and theEvolution of the Fundamental PlaneMichael Boylan–Kolchin 1⋆,Chung–Pei Ma 2†,and Eliot Quataert 2‡1Department of Physics,University of California,Berkeley,CA 94720,USA2Departmentof Astronomy,University of California,Berkeley,CA,94720,USA2February 2008ABSTRACTWe carry out numerical simulations of dissipationless major mergers of elliptical galax-ies using initial galaxy models that consist of a dark matter halo and a stellar bulge with properties consistent with the observed fundamental plane.By varying the den-sity proﬁle of the dark matter halo (standard NFW versus adiabatically contracted NFW),the global stellar to dark matter mass ratio,and the orbit of the merging galaxies,we are able to assess the impact of each of these factors on the structure of the merger remnant.Our results indicate that the properties of the remnant bulge depend primarily on the angular momentum and energy of the orbit;for a cosmo-logically motivated orbit,the eﬀective radius and velocity dispersion of the remnant bulge remain approximately on the fundamental plane.This indicates that the ob-served properties of elliptical galaxies are consistent with signiﬁcant growth via late dissipationless mergers.We also ﬁnd that the dark matter fraction within the eﬀective radius of our remnants increases after the merger,consistent with the hypothesis that the tilt of the fundamental plane from the virial theorem is due to a varying dark matter fraction as a function of galaxy mass.Key words:galaxies:fundamental parameters –galaxies:structure –galaxies:evo-lution –dark matter –methods:N -body simulations1INTRODUCTIONGalaxy merging is thought to be the dominant pro-cess in the formation and evolution of elliptical galax-ies (e.g.,Toomre &Toomre 1972).This picture is broadly supported by both observations and simulations and ﬁts naturally into the ΛCDM hierarchical cosmology (e.g.,Steinmetz &Navarro 2002).Much,however,remains to be understood about the gas and stellar dynamics dur-ing mergers.For example,recent simulations indicate that not all mergers of gas-rich spiral galaxies result in a bulge-dominated remnant (Springel &Hernquist 2005).Although gas-rich starbursts may form many of the stars contained in elliptical galaxies,it is also likely that stars are later assembled into larger remnants via nearly dissipationless mergers,particularly during the formation of groups and clusters (Gao et al.2004).There is in fact direct observational evidence for “red”mergers (lacking signiﬁcant star formation),both in local observations with the Sloan Digital Sky Survey (SDSS;Masjedi and Hogg,private com-⋆E-mail:mrbk@ †E-mail:cpma@ ‡E-mail:eliot@ munication)and in a luminous X-ray cluster at z =0.83(van Dokkum et al.1999).In addition,the semi-analytic study of Khochfar &Burkert (2003)found that the most recent merger of a luminous elliptical galaxy (M B <∼−21)is likely to have been between two bulge-dominated galax-ies rather than two gas-rich spirals,again pointing to the importance of dissipationless merging for the evolution of elliptical galaxies.Observationally,early type galaxies exhibit a well-deﬁned correlation among their eﬀective radii R e ,luminosi-ties L (or equivalently surface brightness I ∝L/R 2e ),and central velocity dispersions σ.This “fundamental plane”(Djorgovski &Davis 1987;Dressler et al.1987)is often ex-pressed as R e ∝σa I b(1)and has been measured by many groups with varying re-sults.For example,Jorgensen,Franx,&Kjaergaard (1996)measured a =1.24±0.07and b =−0.82±0.02from a set of 225early-type galaxies in nearby clusters observed in the r-band.This is consistent with the original obser-vations by Djorgovski &Davis (1987)and Dressler et al.(1987)but noticeably diﬀerent from the SDSS determi-nation (based on ∼9000early-type galaxies)of a =c2005RAS2M.Boylan–Kolchin,C.–P.Ma,and E.Quataert1.49±0.05and b =−0.75±0.01(Bernardi et al.2003b),values more similar tothe K-band fundamental plane of Pahre,de Carvalho,&Djorgovski (1998).The reason for this discrepancy is not currently clear.Projections of the fundamental plane are also of interest in studies of galaxy evolution.The SDSS team measured a radius-luminosity relation of R e ∝L 0.63±0.025(2)and a Faber-Jackson (1976)relation of σ∝L 0.25±0.012(3)(Bernardi et al.2003a),while work by Kauﬀmann et al.(2003)on the stellar mass content of SDSS galaxies allowed Shen et al.(2003)to determine the scaling of eﬀective radius with stellar mass:R e ∝M 0.56∗.(4)The fundamental plane has typically been interpreted as a manifestation of the virial theorem,which relates σand R to the total enclosed (dynamical)mass M dyn and predicts a correlation in the fundamental properties of galaxies:σ2∝M dynLLLIR ,(5)giving the relation R ∝σ2I−1MdynL=MdynL,(7)this tilt could result from increasing M ∗/L with L due to,for instance,varying metallicity or stellar popula-tion age,or from increasing M dyn /M ∗with L due to higher dark matter fraction in the central parts of more luminous galaxies.Conﬂicting conclusions have been re-ported in the literature as to which of these explana-tions is correct (for instance,compare Gerhard et al.2001with Padmanabhan et al.2004).Structural or dynamical non-homology could also contribute to the fundamental plane tilt (e.g.,Capelato,de Carvalho,&Carlberg 1995;Graham &Colless 1997;Pahre,de Carvalho,&Djorgovski 1998).Numerical simulations are a powerful way to assess the dynamics of galaxy mergers.There is a substantial body of work devoted to simulations of mergers of galax-ies in the context of forming ellipticals (for reviews,see Barnes &Hernquist 1992and Burkert &Naab 2003).Sev-eral studies have in particular addressed the question of whether collisionless mergers of galaxies preserve the funda-mental plane relations.These studies typically used simula-tions of ∼104particles (per initial galaxy)and have reached varying and sometimes conﬂicting results.For instance,Gonz´a lez-Garc ´ia &van Albada (2003)studied mergers of one-component systems (stellar bulges without dark matter haloes)with R e ∝M 0.5and found that the merger rem-nants ended up very near the fundamental plane deﬁnedby the progenitors.Dantas et al.(2003)found that mergers of bulge-only galaxies remained on the fundamental plane,while mergers of galaxies containing both bulge and dark matter components produced a fundamental plane with a tilt larger than that observed.Nipoti,Londrillo,&Ciotti (2003)used repeated mergers of one-and two-component galaxies to follow the merging process over a large range in mass.They found that neither the R e −M ∗nor the M ∗−σe relation was preserved in their dissipationless mergers but the full fundamental plane of their merger remnants agreed with observations.In this paper we carry out dissipationless mergers of early type galaxies,focusing on major mergers of two-component (dark matter plus stellar bulge)systems.We thus do not address the origin of either bulge-dominated galaxies or the fundamental plane but rather investigate whether dissipationless mergers maintain the tight funda-mental plane relations,a scenario that is likely important for massive ellipticals.We pay particular attention to us-ing cosmologically motivated models that include adiabatic contraction of dark matter haloes and merger orbits drawn from cosmological simulations.We also use a signiﬁcantly larger number of simulation particles than many previous studies,which is necessary to avoid spurious two-body re-laxation (and an accompanying artiﬁcial expansion of the stellar bulge).In the next section,we describe our initial models and choice of simulation parameters in more detail.Section 3discusses properties of both the stellar and dark matter components of the merger remnants in our simula-tions,including their radial density proﬁles,triaxiality,if and how the fundamental plane scalings and structural ho-mology are preserved,and the changes in the mass ratio M dyn /M ∗in the inner parts of the remnants.Section 4in-cludes a discussion and summary of our results.2SIMULATIONS2.1Galaxy Models and Initial ConditionsOur model galaxies consist of two components,a stellar bulge and a dark matter halo.We model the initial spatial distribution of the bulge with a Hernquist (1990)density proﬁle,ρ∗(r )=M ∗r/a12)a .Observationally,auseful radius is the eﬀective radius R e ,deﬁned as the ra-dius of the isophote that encloses half of the total (pro-jected)stellar luminosity.For equation (8),the eﬀective radius is related to the quarter-and half-mass radii by R e =1.8153a =0.752r 1/2.The Hernquist proﬁle in pro-jection follows the de Vaucouleurs (1948)r 1/4law to within 35%in the radial range 0.06≤R/R e ≤14.5(Hernquist 1990),a region containing over 90%of the model’s total lu-minosity.For the dark matter component,we consider two possible radial density proﬁles:the NFW proﬁle (Navarro,Frenk,&White 1997)and a more realisticc2005RAS,MNRAS 000,1–14Mergers and the Fundamental Plane3version of this proﬁle that uses the adiabatic contrac-tion approximation (Blumenthal et al.1986)to modeltheresponse of thedarkmatter halo to baryons.The uncompressed NFW proﬁle is given by ρdm (r )=ρc δc3[ln(1+c )−c/(1+c )].(10)We use ∆v =200throughout this paper.Since equation (9)is logarithmically divergent as r →∞,we use the expo-nential truncation scheme described by Springel &White (1999)for our haloes at r >r v .Truncating the haloes in this manner requires ≈10%more simulation particles than a sharp truncation at the virial radius but keeps the outer part of the halo in equilibrium.We calculate the adiabatically compressed dark matter density proﬁle from the initial (NFW)dark matter proﬁle and the ﬁnal baryon (Hernquist)proﬁle under the assump-tions of homologous contraction,circular orbits for the par-ticles,and conservation of angular momentum r M (<r ):r i [M b (r i )+M dm (r i )]=r f [M b (r f )+M dm (r i )].(11)Although it is not obvious that the adiabatic contraction ap-proximation should be directly applicable to elliptical galax-ies –it was originally proposed to describe the response of a dark matter halo to baryonic dissipation during disk forma-tion –simulations have shown it to be surprisingly accurate for modeling ellipticals.Recent hydrodynamical simulations (Gnedin et al.2004)ﬁnd that equation (11)overpredicts the amount of contraction at small radii but this diﬀerence is much smaller than the diﬀerence between haloes with and without adiabatic contraction,so we do not expect it to sig-niﬁcantly aﬀect our results.Fig.1shows the initial density proﬁles (top panel)and 1-d velocity dispersions (bottom panel)of the stellar bulge (symbols)and dark matter haloes (plain curves)in our sim-ulations.It also illustrates the eﬀects of compression in the dark matter haloes (solid vs dashed curves).The top panel shows that the mass density interior to R e =2.8kpc is dom-inated by the stellar component when the dark matter halo follows the NFW proﬁle without compression,but compres-sion increases the central dark matter density signiﬁcantly and raises it to be larger than the stellar density at r >∼1pression also steepens the NFW ρ∝r −1densitycusp to nearly isothermal (r −2)at r >∼1kpc (although the compressed density still asymptotes to r −1at very small r ).The bottom panel shows that adiabatic compression in-creases the velocity dispersion of both the dark matter and stellar components.It is also interesting to note that regard-less of compression,the mere presence of a stellar bulge in a dark matter halo increases the velocity dispersion of the dark matter component by up to a factor of ∼2(for r >1kpc)in comparison with that of an NFW halo without a bulge (dotted curve).This eﬀect also greatly reduces the ra-dius at which the “temperature inversion”characteristic of the NFW proﬁle occurs.We construct the N -Body models by setting the bulge and dark matter halo to be in equilibrium in the total gravitational potential.We assume that each component is both spherical and isotropic.The particle positions for each component are initialized from the density proﬁle of that component.The particle velocities are drawn based on each component’s equilibrium distribution function f i (E ),which we calculate numerically using Eddington’s formula (Binney &Tremaine 1987):f i (E )=18π2Ed 2ρi√1011M ⊙0.56kpc (13)Our choices of M dm /M ∗and R e do not guarantee that thevelocity dispersion σe of a model bulge will lie on the ob-served fundamental plane.In fact,observations of the fun-damental plane measure the Faber-Jackson L −σe relation1Note the correct coeﬃcient in Table 1of Shen et al.(2003)is 2.88×10−6rather than 3.47×10−5(S.Shen,private communi-cation)c2005RAS,MNRAS 000,1–144M.Boylan–Kolchin,C.–P.Ma,and E.QuataertFigure 1.Initial radial density proﬁles ρ(r )(top)and 1-d veloc-ity dispersion proﬁles σ(r )(bottom)of the stellar bulge (symbols)and dark matter halo (plain curves)used in our simulations.The dark matter and bulge masses are set to be M dm =1012M ⊙and M ∗=M dm /20here.An adiabatically compressed dark mat-ter halo (solid)has a larger ρand σthan the standard NFW halo (dashed)in the inner tens of kpc.The velocity proﬁle of a standard bulge-less NFW halo of the same mass is plotted (dot-ted curve)for comparison.(The density proﬁle of the bulge-less NFW halo is the same as the uncompressed NFW halo).while our simulations use the M ∗−σe relation.We relate the two using the r ∗band values from SDSS (Bernardi et al.2003a).Assuming M ∗/L =3−3.5in the r ∗band,consis-tent with the estimates of Kauﬀmann et al.(2003),we ﬁnd that a bulge of M ∗=5×1010M ⊙should have a character-istic velocity dispersion of ∼160km/s.Table 1shows that this is reasonably consistent with the values we obtain from model M20(which includes adiabatic contraction)and is no-ticeably higher than the uncompressed halo model (M20u).In order to lie on the M ∗−σe relation,the uncompressed model must have a very large value of M ∗/L ∼8.Adia-batic contraction (and the associated increase in the dark matter fraction at small radii)therefore helps put the initial galaxy models closer to the observed fundamental plane (see,however,Borriello,Salucci,&Danese 2003for an alternate view).In addition to the internal structure of the bulge and dark matter halo,the orbit of a binary encounter is also important in determining the properties of the merger rem-nants.For instance,it is well-known that radial orbits tend to result in prolate remnants whereas orbits with signiﬁcant angular momentum generally give oblate or triaxial end-products (Moore et al.2004and references therein).Most merger studies to date have assumed parabolic orbits with somewhat ad hoc impact parameters.We attempt to use more realistic orbits by drawing from recent results on the orbital distribution of merging dark matter haloes in cosmo-logical N-Body simulations.Benson (2005),for example,has analyzed the orbital parameters of minor mergers in the Virgo Consortium’s N-Body simulations of a ΛCDM model.2He ﬁnds that the orbital distribution peaks at semi-major axis ≈r v and ec-centricity e slightly less than 1.Khochfar &Burkert (2005)studied similar quantities in major mergers (with mass ratio within 4:1)and found that the distribution of circularities peaks at ǫ=√Mergers and the Fundamental Plane5Table1.Simulation and model parameters of each galaxy in the initial conditions used in our production runs(upper5)and test runs.In the run names,the merger orbits are distinguished by “M”and“R”for“most probable”vs.radial(parabolic)orbits; the mass fraction M dm/M∗is labeled by20vs.10;the runs with initially uncompressed dark matter halos are denoted by“u”. Run N20is identical to run M20except the magnitude of each component of the initial orbital velocity is reduced by15%.N dm and N∗are the numbers of dark matter and stellar particles used in each simulation.All dark matter halos have virial masses of 1012M⊙and virial radii of162.6kpc.Run M dmM10105.5×10549000 4.13173.5200 M20205.5×10524500 2.85151.4200N20205.5×10524500 2.85151.4170 M20u205.5×10524500 2.83122.7200R20205.5×10524500 2.83150.4250a eﬀective radius of stellar bulge,in kpcb aperture velocity dispersion of stellar bulge(eq.15),in km s−1 c center-of-mass velocity for merger,in km s−1for our initial galaxy models.We run each model until the remnant reached virial equilibrium(between4and6Gyr de-pending on the orbit).Energy is conserved to within0.5% for all runs and the global virial ratio2T/|W|is unity to within1.5%at theﬁnal timestep in each case.We have performed several convergence tests to ensure that suﬃcient particle numbers and force resolution are used for both the dark matter and stellar components.Weﬁnd that increasing the number of star particles N∗from24500 to49000(runs M20t1and M20t2)atﬁxed dark matter par-ticle number does not aﬀect our results for R e andσe.It is,however,important to use N dm≈5×105dark matter particles per halo since our test runs with N dm≈105show noticeable diﬀerences:for example,if we assume R e∝Mα∗, using N dm=105rather than5×105causes an overesti-mation ofαat the15%level(for a compressed halo with M dm/M∗=20).This eﬀect can be understood in terms of two-body relaxation:using a small number of particles means that on small scales,individual particle interactions become important even when compared to the mean gravi-tationalﬁeld.This causes an artiﬁcial heating,diluting the dark matter potential at the center of the model galaxy,and resulting in an artiﬁcially expanded stellar bulge.Similarly theﬁnal stellar velocity dispersions in the test runs tend to come out lower than in the production runs,again because of the shallower central potential.This eﬀect leads to an over-estimate of R e and an under-estimate ofσe,biasing the fun-damental plane correlations we hope to measure.As listed in Table1,our production runs all use5.5×105dark mat-ter particles and24500stellar particles(for M dm/M∗=20). These values provide enough mass resolution in both dark Figure2.Surface brightness proﬁles for run M20at t=0Gyr (dashed curve)and ten random projections at t=6Gyr(solid curves)as a function of(R/R e)1/4and normalized to unity at R=R e(the initial proﬁle is oﬀset by15%for clarity).A de Vaucouleurs law is a straight line on this plot.and stellar matter to resolve quantities of interest on scales larger than∼1kpc.3PROPERTIES OF MERGER REMNANTS The global merger dynamics in our simulations using the “most probable”orbit is similar in all three cases(runs M10,M20,and M20u).As the galaxies spiral in toward each other,the dense stellar bulges stay intact while the more diﬀuse dark matter haloes mix rapidly.Dynamical friction then brings the bulges and the central core of the dark mat-ter haloes together and the merger isﬁnished after approxi-mately5Gyr.The process for the radial orbit is about30% faster even though the initial orbit is more unbound because the orbit brings the bulges together earlier.In the follow-ing sections we quantify the structure and kinematics of the merger remnants and then discuss the extent to which the merger preserves homology and maintains the fundamental plane relations of elliptical galaxies.3.1Surface Brightness and Radial DensityProﬁlesOne distinctive property of the bulges in early-type galaxies is that their surface brightness proﬁles follow the de Vau-couleurs law,log I(R)∝−R1/4.Fig.2shows I(R)for10 random projections of theﬁnal bulge from run M20(solid lines)as a function of(R/R e)1/4.For comparison we also show I(R)of the initial bulge(dashed line;oﬀset by15%for clarity).Each of the random projections of theﬁnal bulge, as well as the initial proﬁle,all follow the de Vaucouleurs law over the plotted range ofǫ≤R≤R90(where R90is the projected radius containing90%of the bulge mass).c 2005RAS,MNRAS000,1–146M.Boylan–Kolchin,C.–P.Ma,and E.QuataertTable2.Fits to the radial density proﬁles of dark matter haloes and stellar bulges at t=0and6Gyr in ourﬁve production runs. Parameters A,B,and C are deﬁned in equation(14).Haloes areﬁt on the range[1,100]kpc,bulges on the range[0.32,16]kpc.Stellar BulgesRun time M∗r1/4B C(Gyr)(1010M⊙)(kpc)(kpc)100.614.832.5 1.8133.817.334.1 1.8100.49.5239.4 1.8136.812.140.2 1.8100.49.5239.4 1.8144.19.8744.8 1.8100.013415.80.98136.211418.8 1.1100.4 6.8445.2 1.8132.114.637.6 1.7Although the remnants’projected density proﬁlesmimic those of the initial conditions,the unprojected den-sity proﬁles are not necessarily identical.In order to quantifythe changes in density structure induced by the merger,weﬁt both the bulges and dark matter haloes to the followingproﬁle:Aρ(r)=Mergers and the Fundamental Plane7 Figure3.Triaxiality of the merged stellar bulges(top)and darkmatter haloes(bottom)as a function of radius at t=6Gyr fromfour production runs.Axis ratios b/a(left)and c/a(right)areshown(a≥b≥c by deﬁnition).Radial orbits(dotted curves)tend to produce prolate bulges and haloes,whereas orbits withnon-zero angular momentum result in triaxial bulges and nearlyoblate haloes.Note that the ratios for the bulge are plotted lin-early in radius,while those for the halo are plotted logarithmi-cally.with axis ratios that have a mild radial dependence.Theseaxis ratios are in agreement with a recent analysis of theSDSS data that found that bulges of early-type galaxies areconsistent with triaxial ellipsoids(Vincent&Ryden2005),though we note that Alam&Ryden(2002)also found thatprolate ellipsoids are consistent with the SDSS early data re-lease sample.Simulations of a brightest cluster galaxy froma cosmological simulation(Dubinski1998)ﬁnd a stellar rem-nant with b/a=0.66,which is similar to our remnants of the“most probable”orbits,and c/a=0.47,which is closer towhat weﬁnd for a radial merger.The latter is a consequenceof the correlated directions of Dubinski’s multiple mergersalongﬁlaments.The bottom two panels of Figure3show the axis ra-tios for the merged dark matter haloes.The radial orbitagain results in a mostly prolate halo,whereas the three“most probable”orbit runs give nearly oblate haloes withb≈a and c/a≈0.7,largely independent of M dm/M∗and halo compression.It is useful to compare our resultswith those from dark-matter-only cosmological simulationsof Bailin&Steinmetz(2004).For a fair comparison,we cal-culate the axis ratios of our remnants in a shell from0.25to0.4r v,the same range as Bailin and Steinmetz use.Weﬁnd the“most probable”orbit to give b/a≈0.9−0.95and c/a≈0.7while the radial orbit gives a remnant withb/a≈c/a≈0.7.Both agree with the results of Jing&Suto(2002)and Bailin&Steinmetz(cf theirﬁg.5),though ourvalues of b/a tend to be at the high end of their distribution.The diﬀerence in the“most probable”orbit runs be-tween the bulge(triaxial)and halo(oblate)shapes is note-worthy,as it relates to the diﬀerence between the mergingof the haloes and of the bulges.The haloes merge relativelyquickly,but the bulges circle each other and spiral inwarddue to dynamical friction on the haloes.Theﬁnal plunge ofthe bulge tends to be relatively radial even though the initialorbit has substantial angular momentum,giving the rem-nant bulge a diﬀerent shape from the remnant haloes.Quan-titatively,weﬁnd that the amount of(initial orbital)angularmomentum lost from the bulge is∼75%(i.e. L f≈0.25 L i).As a related measure,we calculated the ratio of rotation ve-locity to velocity dispersion for several projections.As mightbe expected,the maximal v rot/σ≈0.5at R e occurs in theplane of the orbit,while for most lines of sight v rot/σ<0.3,typical of a slowly rotating,pressure-supported bulge.Thisis consistent with recent simulations by Naab&Burkert(2003),who found that equal mass mergers of disk galaxiestend to result in pressure-supported ellipticals while merg-ers with mass ratios of3:1and4:1result in oblate rotators(with v rot/σ>0.7).3.3The Fundamental Plane RelationsBefore investigating the scaling relations among the eﬀec-tive radius R e,velocity dispersionσe,and mass of the stel-lar bulge M∗,weﬁrst describe how we determine R e andσe.Because the remnant bulges are triaxial,their observ-able properties depend on the angle from which the bulge isviewed.To quantify this eﬀect,we calculate the properties ofeach of our remnant bulges for104random viewing angles.A standard technique for obtaining the eﬀective radius is toﬁt the projected proﬁle to a Sersic proﬁle and use the de-rived R e as the half-light radius.As described in AppendixA,however,weﬁnd this procedure does not give unique re-sults,so we employ an alternate technique here.We calculatethe surface mass density perpendicular to each line of sightin spherical bins as well as the projected enclosed mass ateach radius.We deﬁne the projected radius of the particleenclosing half the total mass to be the half-light radius R e.This procedure recovers the correct R e for the initial Hern-quist proﬁle to within1-2%.For the velocity dispersion,weuse the surface-brightness weighted dispersion within R e,σ2e≡σ2a(R e)= R e0σ2los(R)I(R)RdR8M.Boylan–Kolchin,C.–P.Ma,and E.QuataertTable3.Mean(left)and mode(right)of the distributions of the eﬀective radius R e and velocity dispersionσe from10000random projections of the remnant bulge in each of ourﬁve production runs.Parametersαandβare the resulting exponents for two projections of the fundamental plane relation:R e∝Mα∗and M∗∝σβe.ModeRun R eσeαβ(kpc)(km/s)6.94200.00.75 4.94.80175.70.75 4.74.85173.00.775.24.53153.00.68 3.16.63162.8 1.238.7 Figure4.Distributions of R e(top)andσe(middle),as well asthe correlation atﬁxed mass between R e andσe(bottom),for 10000random viewings of the merged stellar bulge in runs withM dm=20M∗.Left:“most probable”orbit with vθ/v r≈0.7(runM20).Right:radial orbit(run R20).Note that the mean(dotted line)and mode can diﬀer signiﬁcantly,as the distributions are heavily skewed.The distributions are also dependent on orbit:for run M20the mean R e is greater than the mode and the meanσe is smaller than the mode,while the reverse holds for run R20.In both cases the“observed”R e andσe are highly correlated,as indicated by the bottom two panels.(right panels).The distributions are highly non-Gaussian, although in each case there is a reasonably well-deﬁned modethat diﬀers signiﬁcantly from the mean(indicated by the vertical dotted line).The two orbits result in strikingly dif-ferent distributions of R e andσe.This diﬀerence is primarily because the two classes of orbits yield remnants with diﬀer-ent shapes(see Section3.2above).The“most probable”orbit yields a triaxial remnant for which one is more likely to observe a small R e whereas the radial orbit yields a pro-late remnant for which one is more likely to observe a largeR e.In addition,mergers on orbits with non-zero angular momentum(such as the“most probable”orbit)suﬀer moredynamical friction and thus more energy transfer from thestellar bulge to the dark matter(see also Section3.4and Ta-ble4).This eﬀect leads to a smaller and more tightly boundbulge with a larger velocity dispersion.The bottom panels of Figure4show the correlation be-tween the fundamental plane parameters R e andσe forﬁxedstellar mass from the104viewing angles.It is evident that the measurements are highly correlated;viewing angles thatyield a relatively small eﬀective radius result in a relativelylarge velocity dispersion.This eﬀect is due to projection:looking down the major axis of a prolate remnant,for ex-ample,leads to a smaller eﬀective radius and larger velocitydispersion than if the viewing angle is along a minor axis.These correlations are also expected from the fundamental plane atﬁxed luminosity(or mass):from the SDSS valuesfor equation(1),R e∝σ−3e atﬁxed luminosity.Although the fundamental plane cuts through the R e−σe plane in a non-trivial manner,making a direct comparison betweenthe spread in our R e−σe correlations and the scatter of the fundamental plane diﬃcult,the thickness of the correlations we present here are consistent with the observed small scat-ter in the fundamental plane.However,it is not clear how additional eﬀects,such as scatter in the global M dm/M∗and in initial sizes and shapes of merging galaxies,would aﬀect this scatter.Using the results of Figure4,we can now assess theextent to which the stellar bulges remain on the projectionsof the fundamental plane after major dissipationless merg-ers.Table3lists the mean and mode of R e andσe for the merged stellar bulges and the slopes for power-lawﬁts to R e−M∗and M∗−σe from ourﬁve production runs.Since the mean and modes diﬀer signiﬁcantly,we present results for each deﬁnition of the“average”remnant.The results for R e−M∗shown in Table3are more robust than those for M∗−σe because of the steepness of the latter relation.Table3shows that for the“most probable”orbitwith adiabatically compressed dark matter haloes(i.e.runs “M10”and“M20”,which are the best motivated models studied in this paper),the derived fundamental plane slopes using the mode are reasonably consistent with observations: R e∝Mα∗,α=0.64−0.69,c 2005RAS,MNRAS000,1–14。

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