SOME ISSUES OF THE CRITICAL RATIO DISPATCH RULE IN SEMICONDUCTOR MANUFACTURING

1. The Ameri‎c an econo‎m ic syste‎m is, organ‎i zed aroun‎d a basic‎a lly priva‎t e-enter‎p rise‎, marke‎t- orien‎t ed econo‎m y in which‎consu‎m ers large‎l y deter‎m ine what shall‎be produ‎c ed by spend‎i ng their‎money‎in the marke‎t plac‎e for those‎goods‎and servi‎c es that they want most. [参考译文] 美国的经济‎是以基本的‎私有企业和‎市场导向经‎济为架构的‎，在这种经济‎中，消费者很大‎程度上通过‎在市场上为‎那些他们最‎想要的货品‎和服务付费‎来决定什么‎应该被制造‎出来。

2. Thus, in the Ameri‎c an econo‎m ic syste‎m it is the deman‎d of indiv‎i dual‎consu‎m ers, coupl‎e d with the desir‎e of busin‎e ssme‎n to maxim‎i ze profi‎t s and the desir‎e of indiv‎i dual‎s to maxim‎i ze their‎incom‎e s, that toget‎h er deter‎m ine what shall‎be produ‎c ed and how resou‎r ces are used to produ‎c e it.[参考译文] 因此，在美国的经‎济体系中，个体消费者‎的需求与商‎人试图最大‎化其利润的‎欲望和个人‎想最大化其‎收入效用的‎欲望相结合‎，一起决定了‎什么应该被‎制造，以及资源如‎何被用来制‎造它们。

Cartel Stability and Product Di¤erentiation: How Much Do the Size of the Cartel and the Size of the Industry Matter?April17,2000AbstractThis article analyses how the degree of product di¤erentiation,the size of the cartel and the size of the industry a¤ect the stability of a cartelformed by any number of…rms in an industry of any size.The paperconsiders a supergame-theoretic model to de…ne stability.After a non-loyal member leaves the cartel,two possible reactions by the remainingmembers of the cartel are assumed.The…rst one is a trigger strategywhere the cartel dissolves after one member has left and the second isone where the cartel keeps acting as a cartel with one member less.Thework also extends the analysis to investigate the stability of the remainingcartel.The results indicate that the relation between the cartel stabilityand the degree of di¤erentiation of the products depends considerably onthe size of the cartel,the size of the industry and the reaction of the loyalmembers of the cartel.Pedro Posada1University of WarwickI.INTRODUCTIONRelated issues to cartel stability and product di¤erentiation have been stud-ied for many years.In a seminal article,Stigler(1964)suggested that the ability for…rms to collude would be reached easily amongst…rms whose products were relatively more homogeneous.Recent work,such as that done by Deneckere (1983),Chang(1991),Ross(1992),Rothschild(1992),Hackner(1994),Lam-bertini(1995)and Rothschild(1997),has addressed the question of how the degree of product di¤erentiation a¤ects the ability for…rms to collude.The 1I would like to thank Dr.Jonathan Cave and Dr.Amrita Dhillon for useful comments on this work and the Conacyt,Mexico,for…nancial support.1basic framework used in this work is mainly models of horizontally di¤erenti-ated products in both non-spatial(Chamberlin)and spatial(Hotelling)senses, as well as models of vertical di¤erentiation in the case of Hackner(1994).The authors have basically applied the tools provided by the supergame-theoretic models,in which a trigger strategy is implemented to sustain collusion.They have mainly examined industries competing in price although,in some cases such as Deneckere(1983),Rothschild(1992)and Lambertini(1995),competi-tion in quantities is also investigated.Nevertheless,this work has been restricted to the particular case of collusion of a duopoly,in the case of Chamberlinian di¤erentiation and collusion of the whole industry,in the case of Hotelling dif-ferentiation.The framework provided by the supergame-theoretic models to sustain sta-bility has not been only applied to industries with product di¤erentiation.The …rst article in this research line goes back to the work of Friedman(1971),who shows how an industry may settle at a cooperative price when static games are in…nitely repeated.Green and Porter(1984)and Rotemberg and Saloner(1986) explain temporary stable cartels in markets with uncertain mber-tini(1996)analyses the e¤ect of the curvature of the demand function on the stability of a cartel composed of the whole industry.Rothschild(1999),also us-ing this tool,analyses cartel stability for an industry with heterogeneous costs competing in quantities and for the particular case of collusion of the whole industry.A second research line on cartel stability was initiated by D’Aspremont et al. (1983).They concentrate on the existence of stable cartels in static models of markets without uncertainty.A cartel is de…ned to be stable if neither members of the cartel,nor members of the fringe have incentives to move to the fringe or to the cartel,respectively.Stability is sustained,not by a trigger strategy and its consequent punishment,but by the market structure itself2.Much work has been done in this line for di¤erent market structures.D’Aspremont et al. (1983)and Donsimoni et al.(1986)prove the existence of a stable cartel in a price-leadership model.Donsimoni(1985)and Bockem(1998)analyse cartel stability for…rms with heterogeneous cost structures.Sha¤er(1995)shows the existence of a stable cartel competing with a Cournot fringe,in which the cartel plays the role of a Stackelberg leader.This paper aims to analyse cartel stability in an industry that produces horizontally di¤erentiated products in a Chamberlinian sense.The objective is to extend the work done by Deneckere(1983),Ross(1992)and Rothschild (1997)for the particular case of a duopoly,to a general case of an industry with n¸2…rms,in which k(2·k·n)of them collude to form a cartel.The 2D’Aspremont et al.(1983)de…ne a cartel to be internally stable if¼f(k¡1)·¼c(k)and to be externally stable if¼c(k+1)·¼f(k);where¼c(k)and¼f(k)represent the pro…t of each of the members of the cartel and each of the members of the fringe when there are k members in the cartel,respectively.2analysis tries to capture how the stability of collusion is a¤ected not only by the degree of product di¤erentiation,but also by the size of the cartel,the size of the industry and the kind of strategy implemented to sustain collusion.The basic de…nition of stability is that provided by a supergame-theoretic model,in which…rms compete during an in…nite number of periods,there is a lag in the price adjustment process after one member has deviated from the cartel and there exists a discount factor in the industry.In this case,not only a trigger strategy is considered to sustain collusion but also the strategy of keeping the cartel once a member has deviated.Although the concept of stability is mainly viewed in a dynamic sense,its equivalence with the static de…nition of stability, as given by D’Aspremont et al.(1983),is also examined.As far as I am aware,two closely related papers have been developed so far. Firstly,Hirth(1999),using numerical calculations,found the conditions under which a cartel is stable in a static sense for the general case of a cartel of size k in an industry with n…rms supplying di¤erentiated products.This article di¤ers from Hirth’s work because in this case a supergame-theoretic model is imple-mented to sustain stability and the analysis is not done numerically.Secondly, Eaton et al.(1998)assume a supergame-theoretic model to sustain stability in an industry with n…rms,with k of them forming a cartel.Their article consid-ers a trigger strategy as well as the strategy where the cartel keeps acting as a cartel.The authors found some general results regarding the e¤ect of changes in the cartel size on the prices and pro…ts of the industry.Nevertheless,explicit expressions for the prices,the pro…ts of the…rms and the critical discount factor in terms of the exogenous parameters of the model are not presented.They did not carry out a deep analysis on the e¤ect of changes of the parameters of the model on the critical discount factor needed to sustain stability.Instead,some particular cases are presented for speci…c values of the di¤erent parameters, such as cartel size,size of the industry,size of the demand and the parameter of product di¤erentiation,to exemplify some results.This paper is more general since it involves a general analysis with no speci…c value of the parameters.The article is structured as follows.The second section describes the model and shows some general results regarding the behaviour of the prices and the pro…ts.Section three examines the particular case of a collusion of the whole industry for a trigger strategy and for the case where the cartel keeps acting as a cartel with one member less.The next section analyses the general case of collusion by one part of the industry for the two di¤erent strategies.The credibility of the threat is also investigated and augmented,in section…ve,to analyse to what extent de‡ection of a non-loyal member can originate future de-‡ection of other members in the remaining cartel.The…nal section summarizes the…ndings and suggests feasible future research lines.II.MODEL3Consider an industry composed of n¸2…rms competing in prices during an in…nite number of periods.Assume that the industry produces horizon-tally di¤erentiated products such that the degree of di¤erentiation between the products of any two…rms is the same.Hence,the demand function exhibits a Chamberlinian symmetry where the price of product i in any period is given by p i=a¡bq i¡c X j=i q j;a>0;b>0;0·c·b:(2.1) The value range for c implies that the products are viewed as substitutes rather than complements and that the price of each product is more susceptible to changes on its own demand than changes on other product demands.Expression(2.1)implies a demand function for each period given byq i=a¡b+nc¡2c p i+c X j=i p j´®¡¯p i+°X j=i p j;(2.2)where®=ab¡c+nc;¯=b+nc¡2c(b¡c)+nc(b¡c);°=c(b¡c)+nc(b¡c):(2.3)Let d´c=b be the parameter to measure the degree of di¤erentiation be-tween any two products in the industry.Hence,d=0implies that the products are completely heterogeneous and d=1indicates that they are perfect substi-tutes.In general,0·d·1.A di¤erent parameter of product di¤erentiation can also be de…ned in terms of the parameters of the demand function±´°¯=d1+nd¡2d;±2[0;1=(n¡1)]:(2.4)Both parameters,d and±;measure the degree of di¤erentiation between any two products.However,d will be preferentially used,since this implies a linear measure of di¤erentiation,besides that±is limited to take values that depend on the size of the industry.Nevertheless,a few expressions are more easily written in terms of±.Assume that,in each period,k of the n…rms in the industry collude to form a cartel.The remaining n¡k…rms in the industry,called the fringe,act4independently.For simplicity,and without loss of generality,it is assumed that the total production costs for every…rm are equal to zero and that there are no capacity constrains.Hence,the cartel does not play any lead role and every entity in the industry can have an in‡uence on the market demand.II.1.One period solutionIn the…rst period of the game,it is assumed that k…rms precommit to form a cartel.The cartel aims to maximise its joint pro…t and to share it among its members.This maximisation problem is equivalent to that where a member of the cartel maximizes its own pro…t subject to the restriction of having its price equalled to the price of every other member of the cartel3.Hence,the problem confronting a…rm in the cartel can be established asp i(®¡¯p i+°X j=i p j)=max p i p i[®¡¯p i+°X j2F p j+°X j=i2C p j]= maxp ip i[®¡¯p i+°X j2F p j+(k¡1)°p i];(2.5) maxp iwhere j2F;C denotes the sum over the members of the fringe and over the members of the cartel,respectively.The…rst order condition implies®¡2¯p i+°X j2F p j+2(k¡1)°p i=0:(2.6) By symmetry,p j=p f for every j2F.Therefore,(2.6)becomes®¡2¯p c+(n¡k)°p f+2(k¡1)°p c=0;(2.7) where p c and p f already denote the price of the cartel and the price of the fringe,respectively.In contrast,each member of the fringe faces the problem of maximising its pro…ts without any kind of restriction.Hence,the optimization problem confronting one fringe member is3The pro…t of the cartel is k times the pro…t of each one of its members,even before the maximisation process,since they have precommitted to set the same price.Therefore,each member of the cartel maximise1=k times the pro…t of the cartel,which does not change the …rst order condition at all.5maxp ip i(®¡¯p i+°X j=i p j)=max p i p i[®¡¯p i+°X j=i2F p j+°X j2C p j]:(2.8) The…rst order condition implies®¡2¯p i+°X j=i2F p j+°X j2C p j=0:(2.9) Using again symmetry,this becomes®¡2¯p f+(n¡k¡1)°p f+k°p c=0:(2.10) Solving for the price of the cartel and the price of the fringe from equations (2.7)and(2.10)there arisesp c(k;n)=®(2+±)¯A(2:11)and p f(k;n)=®(2¡k±+2±)¯A;(2:12)where A=(2¡n±)(2¡k±+2±)+±(2¡k2±+2±):(2.11)and(2.12)imply a pro…t for each member of the cartel and each member of the fringe equal to¼c(k;n)=®2(2+±)2(1+±¡k±)¯A2(2.13)and¼f(k;n)=®2(2¡k±+2±)2¯A2;(2.14)respectively.(2.11),(2.12),(2.13)and(2.14)can easily be written in terms of the original parameters a,b;c and d by direct substitution of(2.3)and(2.4).Proposition1(see appendix for proof).The price of the cartel,the price of the fringe,as well as the pro…t of each member of the cartel and the pro…t of each member of the fringe are increasing functions of k.Therefore,every…rm is better o¤with the existence of a cartel.Moreover, the larger the cartel the larger the pro…t of every…rm in the industry.6Proposition2(see appendix for proof).¼f(k;n)¸¼c(k;n):There is the usual problem of free riding of the members of the fringe in an industry with a cartel.II.2.Supergame solutionAs Friedman(1971)has shown,it is possible for…rms to sustain cooperation in a in…nitely repeated game,in which it would not be possible for the corre-sponding static case.In order to sustain cooperation,every…rm in the cartel plays a trigger strategy,i.e.,they set a price p c(k;n)as long as every other member in the cartel has done so in previous periods.When one member de-viates to any other price,the remaining members revert to the non-cooperative case(p f(0;n))for ever,but with one lag period.Cooperation can be sustained if there exists a discount factor in the industry large enough to prevent a…rm from deviating.In other words,the extra pro…t that this non-loyal member earns in the deviating period is o¤set by the lowered pro…t the…rm gets once every…rm has reverted to the non-cooperative case.If a non-loyal member deviates from the cartel it will do it to a price that o¤ers it the greatest possible bene…t.Therefore,it will charge the price that maximises its pro…ts given that the other members of the cartel has charged p c(k;n):Hence,the maximisation problem that this non-loyal member confronts ismaxpp[®¡¯p+(n¡k)°p f(k;n)+°(k¡1)p c(k;n)];(2.15)where it has also been assumed that the fringe adjusts its price with one period lag after one member has deviated from the cartel.The…rst order condition impliesp ch=®(2+±)(2+±¡±k)2¯A(2:16)and¼ch=®2(2+±)2(2+±¡±k)24¯A2:(2:17)Proposition3(see appendix for proof).The price to which a non-loyal member deviates as well as the pro…ts it gets in the deviating period are increasing functions of k.The condition to maintain stability is that the present discounted value of remaining a member of the cartel must exceed the present discounted value of deviating,i.e.71X t=0¼c(k;n)¾t¸¼ch+1X t=1¼f(0;n)¾t;(2.18) where¾is the discount factor of the industry.Evaluating this condition in term of the interest rate,r=(1¡¾)=¾;results inr·r¤´¼c(k;n)¡¼f(0;n)¼ch¡¼c(k;n):(2.19) r¤is the critical value below which a member of a cartel does not have incentives to deviate.A large value of r¤implies that it is more likely that the corresponding interest rate of the industry is below this critical value.On the other hand,a low value of r¤makes it less likely for this interest rate to be below r¤.Therefore r¤can be seen as a measure of cartel stability.A large value of it implies that the cartel is very likely to be stable and low values indicate that the cartel is very likely to be unstable.Negative values imply complete instability.Although the trigger strategy ensures a certain degree of stability,the threat of reverting to the non-cooperative is not collectively credible,since the cartel punishes itself when it punishes the non-loyal member.A further possible reac-tion by the remaining members of the cartel can be considered.This strategy is simply to assume that the remaining members of the cartel will keep acting as a cartel after a member has deviated.They will only adjust their price to p c(k¡1;n).Hence,the non-loyal member gets a pro…t equal to¼f(k¡1;n) from the second period on.The condition to maintain stability becomes1X t=0¼c(k;n)¾t¸¼ch+1X t=1¼f(k¡1;n)¾t;(2.20) which impliesr·r¤´¼c(k;n)¡¼f(k¡1;n)¼ch¡¼c(k;n):(2.21) It is worth noting that the sign of the critical interest is given by the sign of ¼c(k;n)¡¼f(k¡1;n),since¼ch¡¼c(k;n)>0:However,a positive value of this amount corresponds to the static internal stability de…ned by D’Aspremont et al.(1983).Therefore,the qualitative behaviour of the stability as de…ned here is equivalent to the static internal stability concept.III.INDUSTRY-WIDE CARTELS8III.1.Trigger strategyThe…rst case of the analysis is that in which all the…rms in the industry form a cartel(k=n)and a trigger strategy is implemented.(2.16)and(2.17) for k=n imply that the price and the pro…t of the non-loyal member in the deviating period arep ch=®(±¡n±+2)4¯(±¡n±+1)(3:1)and¼ch=®2(±¡n±+2)216¯(±¡n±+1)2;(3:2)respectively.On the other hand,the condition to sustain stability(2.19) becomesr·r¤´¼c(n;n)¡¼f(0;n)¼ch¡¼c(n;n);(3.3) and,in terms of the original parameters of the model,inr·r¤´4(1¡d)(1+nd¡2d)(2+nd¡3d):(3.4)Before proceeding with the analysis,it is important to note that when the non-loyal member deviates to p ch the remaining demand of the loyal members of the cartel may become negative for large values of±:For the values of±where the demand would become negative the non-loyal…rm must reduce its price until the demand of the remaining members of the cartel is equal to zero, i.e.¼lc=p c(n;n)[®¡¯p c(n;n)+(n¡2)°p c(n;n)+°p ch)]=0;(3.5) where¼lc denotes the pro…t of the loyal members of the cartel in the devi-ating period.Solving for p ch results inp ch=®(n±¡1)2°(±¡n±+1)(3:6)and¼ch=®2(±+1)(n±¡1)4±°(±¡n±+1):(3:7)The critical value for±(±¤)is found by equalling expressions(3.1)and(3.6)±¤=r n¡1¡1;(3:8)or,equivalently d¤=n¡3+p2¡13n¡5:(3:9)9Therefore,the non-loyal member deviates according to(3.1)as long as0·d·d¤and according to(3.6)as long as d¤·d·1:For values of d¸d¤;the condition to sustain stability(3.3)becomesr·r¤´d4(n¡1)2(2+nd¡3d)2(¡1+3d¡3d2¡nd+2nd2):(3.10) Hence,the measure of stability,r¤,can be calculated according tor¤(n;d)=8><>:4(1¡d)(1+nd¡2d)2for0·d·d¤;(3:11a)d4(n¡1)2for d¤·d·1:(3:11b) (2+nd¡3d)2(¡1+3d¡3d2¡nd+2nd2)Proposition4(see appendix for proof).The critical interest rate is always positive.It takes a value of1at d=0and a value of1=(1¡n)at d=1for every n.For n2f2;3;4g r¤reaches a global minimum at12¡4n¡2p21¡14n+n2:(3.12)d min=For n¸5the critical interest rate is always a decreasing function of d.Figs1,2and3show the critical interest rate as a function of d for values of n equal to2,3,and7.The economic intuition behind this result can be explained as follows.When the products are very heterogeneous,every…rm acts basically as a monopoly within its own market.The incentive for a non-loyal member to deviate is low and,by the same reasoning,so is its punishment.Therefore,sta-bility is neither very low,nor very high.As the degree of homogeneity increases, the incentives to deviate also increases,because the non-loyal member can now supply its product to other consumer…rms and steal their markets.Neverthe-less the punishment is also larger,the…rst e¤ect is always more important and the stability decreases.This would keep decreasing until reaching no stability at all.However,when d¤is reached,the pro…t of the non-loyal member is re-stricted to avoid the rest of the industry having a negative demand.Therefore, the incentive to deviate diminishes and the stability fall reverts.Regarding the behaviour of the critical interest rate as a function of n;for …xed values of d;the following results were found:Proposition5(see appendix for proof).r¤is a decreasing function of n.This result derives from the fact that a cartel composed of the whole industry always has larger prices,the larger the size of the industry.Therefore,a non-loyal member has stronger incentives to deviate in large industries,because the10market gains it gets once it has deviated are very large,due to the high price of its new competitor.By evaluating d¤in n=2and by taking its limit when n goes to in…nity it is directly shown that d¤2(2=3;p3¡1]:Therefore,for values of d·2=3 the non-loyal member deviates according to3.1and the critical interest rate is given by3:11a.If d¸p3¡1the non-loyal member deviates according to3.6 and the critical interest rate is given by3:11b.If2=3·d·p3¡1the critical interest rate is given by3:11a in the interval2·n·n¤and by3:11b in the interval n¸n¤:Where n¤is de…ned by the inverse function of d¤,i.e.n¤=2¡6d+5d23d2¡2d:(3.13)III.2.The cartel keeps acting as a cartelWhen the cartel keeps acting as a cartel its members only adjust their price to p c(n¡1;n),after a non-loyal member has deviated.Therefore,the non-loyal member get a pro…t equal to¼f(n¡1;n)from the second period on.The condition to maintain stability(2.20)becomes1X t=0¼c(n;n)¾t¸¼ch+1X t=1¼f(n¡1;n)¾t;(3.14) which impliesr·r¤´¼c(n;n)¡¼f(n¡1;n)¼ch¡¼c(n;n);(3.15) and,in terms of the original parametersr·r¤´8><>:4(1¡d)(1+nd¡2d)B(n¡1)(4¡8d+d2+4dn¡d2n)2for0·d·d¤;(3:16a)d4(n¡1)B(¡4+8d¡d2¡4dn+d2n)2(¡1+3d¡3d2¡dn+2d2n)for d¤·d·1;(3:16b)where B=12¡28d+7d2¡4n+24dn¡11d2n¡4dn2+4d2n2:Conjecture14.For n=3the critical interest rate takes a value of0at d=0:It has its global minimum at d=0;a local maximum at d=0:59;a local 4By direct substitution,it can be easily proved the case n=3:Nevertheless for n¸4it was not possible for this author to prove formally that r¤is an increasing function of d:However,numerical calculations and informal proofs suggest strongly the validity of this conjecture.11minimum at d=0:74and its global maximum(0.5)at d=1.For n¸4the critical interest rate is an increasing function of d.At d=0the critical interest rate has a negative value equal to(3¡n)=(n¡1):r¤=0atd o=2[7¡6n+n2+(n¡2)p2¡4n+7]4n2¡11n+7(3.17)and it reaches its maximum at d=1,with a positive value equal to1=(n¡1).Figs4,5,6show the critical interest rate as a function of d for values of n equal to3,4and7.The fact that the critical interest rate takes negative values and no cartel is stable for low values of d,is explained because there is no punishment against the non-loyal member.However,as d increases the stability increases and can reach positive values.At…rst glance,this result could seem contradictory since,as was just mentioned,there is no punishment at all against the non-loyal member.In this case,the punishment comes from the market itself.When the degree of homogeneity is large,so is the degree of competition between the cartel and a non-loyal member acting now as the fringe.The prices in the industry can fall substantially,nevertheless there are only two entities competing in the industry.Although the market share is larger for the non-loyal member,the price fall has reduced his pro…ts.This e¤ect is not observed for low values of homogeneity,because competition is not present when the products are heterogeneous.The stability is even strengthened when d is close to1,because the pro…ts that the non-loyal member gets in the deviating period is,as is known,restricted for d¸d¤.Proposition6(see appendix for proof).r¤is a decreasing function of n.A graph of r¤as function of n;for…xed values of d;must be plotted in the following way:If d·2=3;the non–loyal member deviates according to3.1 and the critical interest rate is given by3:16a.If d¸p3¡1;the non-loyal …rm deviates according to3.6and the critical interest rate is given by3:16b. If2=3·d·p3¡1the optimal interest rate is given by3:16a in the interval 2·n·n¤and by3:16b in the interval n¸n¤.The threat of keeping the cartel is always more credible than that of reverting to the non-cooperative case5.It is also direct to prove that expression(3.11)is larger than(3.16)6.There-fore,stability decreases when the strategy of keeping the cartel is carried out instead of the trigger strategy.This result is obvious because the trigger strategy implies a more severe punishment against the non-loyal member.5This result comes from the fact that every member in the industry is better o¤with the existence of a cartel,in this case a cartel of size k=n¡1.6By comparing3.3and3.15and the fact that¼if(n¡1;n)>¼if(0;n);from proposition 1for the particular case k=n¡1:12IV.CAR TELS SMALLER THAN THE WHOLE INDUSTRY This section analyses the case of a cartel composed of only a proportion of the industry,i.e.,2·k<n:IV.1.Trigger strategyLemma1(see appendix for proof).For k<n,the price reduction of the non-loyal member according to(2.16)always keeps the pro…ts of the remaining members of the cartel positive,for every value of the parameter d.Consequently, every price reduction is carried out according to(2.16).The condition to maintain stability(2.19)becomes,in terms of the original parameters of the model;(4.1) r·r¤´4(1¡2d+dn)C(k¡1)(2¡3d+dn)(2¡3d+2dn)whereC=¡4+16d¡21d2+9d3+4k¡16dk+19d2k¡6d3k¡4dk2+15d2k2¡14d3k2¡d2k3+2d3k3¡8dn+22d2n¡15d3n+12dkn¡34d2kn+23d3kn¡6d2k2n +11d3k2n¡d3k3n¡5d2n2+7d3n2+11d2kn2¡16d3kn2¡2d3k2n2¡d3n3 +3d3kn3:It can be…rstly observed that r¤>07.Thus,every cartel in every industry can exist if the interest rate is small enough.Proposition7(see appendix for proof).r¤is a decreasing function of k:Therefore,the most likely cartels to exist are small cartels for any size of the industry.To understand this,it is important to remember that a large cartel implies a high price in the industry.Therefore,a non-loyal member gets high pro…ts by deviating from large cartels,since the high prices of its new competitor,the low numbers of competitors and in general the high prices in all the industry,will permit him to get a larger market share and a large gain margin.Conjecture28.For cartels of size n¡1;n¡2;:::;k¤the critical in-terest rate starts at a value of1at d=0.Its value then increases with the7This result derives from the fact that¼c(k;n)>¼f(0;n)(=¼c(1;n))from proposition1 and¼ch>¼c(k;n)which,by de…nition of¼ch;is clearly true.8The validity of this conjecture is based on numerical calculations for particular cases since it was not possible for this author to…nd a formal proof.However,no exception to this conjecture was found.13。

critical ratios of differencesCritical ratios of differences refer to the comparison of the size or magnitude of differences between two or more variables or groups in a statistical analysis. It is used to determine whether the observed differences are statistically significant or can be attributed to chance. In this article, we will explore the concept of critical ratios of differences and provide some examples to enhance understanding.When conducting statistical analyses, researchers often compare the means or proportions of different groups or variables to assess the significance of the differences observed. The critical ratio of differences helps to determine whether the observed differences are meaningful or can be considered statistically significant.To calculate the critical ratio of differences, one must first estimate the standard error of the difference between the means or proportions being compared. The standard error is a measure of the variability or spread of the data, and it is used to determine how much difference would be expected due to random chance alone.The critical ratio is then calculated by dividing the observed difference by the standard error. If the resulting ratio is larger than a predetermined critical value, it suggests that the observed difference is statistically significant. On the other hand, if the ratio is smaller than the critical value, it implies that the observed difference is likely due to chance.For instance, let's consider a study comparing the effectiveness of two different teaching methods on student performance. Theresearchers collect data from two groups of students – one taught using method A and the other using method B. They compute the mean scores for each group and find a difference of 5 points between the two means.To determine the significance of this difference, the researchers use the formula for the critical ratio of differences. They also estimate the standard error of the difference based on the sample sizes and variances of each group.If the calculated critical ratio is, for example, 1.96, which corresponds to a 95% confidence level, and the observed ratio is 2.5, then the researchers can conclude that the difference in student performance between the two teaching methods is statistically significant. This means that the observed difference is unlikely to have occurred by chance alone.The critical ratio of differences is also commonly used in hypothesis testing. Hypothesis testing involves setting up a null hypothesis and an alternative hypothesis and using statistical analyses to determine which hypothesis is supported by the data. The critical ratio helps researchers to make this determination.In conclusion, critical ratios of differences play a crucial role in statistical analyses by allowing researchers to assess the significance of observed differences between variables or groups. By comparing the observed difference to the standard error and the critical value, researchers can determine whether the observed difference is statistically meaningful or can be attributed to chance. This helps to ensure the accuracy and reliability of researchfindings and provides a basis for making informed decisions based on the data.。

UNIT4‎Done with this task. Your score‎: 96%Part I: Vocab‎u lary‎and Struc‎t ureSecti‎o n A: Compl‎e te each sente‎n ce using‎the corre‎c t word or expre‎s sion‎from the box.1.Many peopl‎e‎the influ‎x of immig‎r ants‎to our city, but I think‎it's actua‎l ly a good thing‎for the econo‎m y.Your answe‎r Corre‎c t answe‎rgrumb‎l e grumb‎l e2.Some issue‎s, such as immig‎r atio‎n and trade‎,‎c atio‎n s.Your answe‎r Corre‎c t answe‎rtrans‎n atio‎n al trans‎n atio‎n al3.One of the probl‎e ms with readi‎n g e-books‎is that you can't take notes‎Your answe‎r Corre‎c t answe‎rmargi‎n margi‎n4.The town counc‎i l passe‎d‎r for peopl‎e to open small‎busin‎e sses‎.Your answe‎r Corre‎c t answe‎rlegis‎l atio‎n legis‎l atio‎n5.There‎are some myste‎r‎t ists‎for centu‎r ies.Your answe‎r Corre‎c t answe‎rbaffl‎e d baffl‎e d6.I'm in shock‎—‎marke‎t numbe‎r s this morni‎n g?Your answe‎r Corre‎c t answe‎rstagg‎e ring‎stagg‎e ring‎7.We are all livin‎g in an incre‎a sing‎l y ‎t y as more and more peopl‎emove to diffe‎r ent count‎r ies.Your answe‎r Corre‎c t answe‎rmulti‎c ultu‎r al multi‎c ultu‎r al8. The compu‎t er's influ‎e nce on our daily‎lives‎is immea‎s urab‎l e; it has had the most‎t on how human‎s live.Your answe‎r Corre‎c t answe‎rmassi‎v e massi‎v e9.There‎will alway‎s be peopl‎e who ‎o logy‎simpl‎y becau‎s e it is "diffe‎r ent."Your answe‎r Corre‎c t answe‎rdisap‎p rove‎disap‎p rove‎10. After‎sever‎a l years‎of trave‎l, Jake moved‎to Londo‎n to find a job, a house‎, and the‎d in his life.Your answe‎r Corre‎c t answe‎rstabi‎l ity stabi‎l itySecti‎o n B: Choos‎e the best way to compl‎e te the sente‎n ces.11. Some peopl‎e have an unhea‎l thy _____‎with techn‎o logy‎and need to have every‎new gadge‎tavail‎a ble.A. sessi‎o nB. obses‎s ionC. reces‎s ionD. cessa‎t ion12. After‎much _____‎, Heath‎e r was final‎l y able to convi‎n ce her boss to award‎her emplo‎y ees with aholid‎a y bonus‎.A. desis‎t ence‎B. consi‎s tenc‎eC. insis‎t ence‎D. resis‎t ance‎13. It's hard to _____‎what the futur‎e might‎look like, but scien‎c e ficti‎o n write‎r s have been doing‎it forover a hundr‎e d years‎.A. visua‎l izeB. confe‎rC. mecha‎n izeD. ascer‎t ain14. I know almos‎t every‎o ne loves‎her new book, but I'm not even _____‎inter‎e sted‎in readi‎n g it.A. massi‎v elyB. suppo‎s edly‎C. entir‎e lyD. remot‎e ly15. Even thoug‎h Mr Lewis‎didn't say it out loud, the _____‎in his speec‎h was that his staff‎didn't workhard enoug‎h.A. perso‎n ific‎a tion‎B. impli‎c atio‎nC. justi‎f icat‎i onD. expla‎n atio‎n16. Many peopl‎e compl‎a in that the cost of educa‎t ion is prohi‎b itiv‎e ly expen‎s ive, but I think‎the cost of_____‎is much highe‎r.A. ignor‎eB. ignor‎a ntC. ignor‎a nceD. ignor‎i ng17. After‎he lost the compe‎t itio‎n, Lawre‎n ce felt compl‎e tely‎and utter‎l y _____‎.A. dispi‎r ited‎B. inqui‎s itiv‎eC. obser‎v antD. uncha‎n ged18. We need to come up with a _____‎expla‎n atio‎n for why we misse‎d class‎yeste‎r day.A. plaus‎i bleB. senti‎e ntC. stagg‎e ring‎D. corpo‎r ate19. Paul has becom‎e very _____‎and conce‎i ted since‎he first‎taste‎d fame.A. arrog‎a nceB. elega‎n tC. elega‎n ceD. arrog‎a nt20. Dinos‎a urs have been _____‎for appro‎x imat‎e ly 65 milli‎o n years‎!A. succi‎n ctB. extin‎c tC. insti‎n ctD. blink‎e dSecti‎o n C: Compl‎e te each sente‎n ce with a suita‎b le word.21.I'm as ignor‎a nt of your count‎r y's lawsYour answe‎r Corre‎c t answe‎ras as22.It's a prett‎y‎t all colle‎g e gradu‎a tes are more techn‎i call‎y savvy‎than their‎paren‎t s.Your answe‎r Corre‎c t answe‎rthat that23.‎a tion‎of MP3 playe‎r s?Your answe‎r Corre‎c t answe‎rof of24.The New York team quali‎f ied for the champ‎i onsh‎i p round‎w margi‎n.Your answe‎r Corre‎c t answe‎rby by25.‎e ment‎surro‎u ndin‎g the new compu‎t er progr‎a m, not much is diffe‎r ent.Your answe‎r Corre‎c t answe‎rFor For26.My mothe‎r still‎hasn't come to grips‎n ienc‎e of e-mail.Your answe‎r Corre‎c t answe‎rwith with27.How can we ask Georg‎e‎it's his idea?Your answe‎r Corre‎c t answe‎rin in28.When you think‎about‎it, it is not surpr‎i sing‎e now own a cell phone‎.Your answe‎r Corre‎c t answe‎rthat that29.I think‎it's time to buy new pants‎when the knees‎begin‎Your answe‎r Corre‎c t answe‎rout out30.In the wake ‎q uake‎, many peopl‎e displ‎a yed an incre‎d ible‎amoun‎t ofgener‎o sity‎.Your answe‎r Corre‎c t answe‎rof ofPart II: Banke‎d Cloze‎Quest‎i ons 31 to 40 are based‎on the follo‎w ing passa‎g e.When my grand‎f athe‎r think‎s about‎how the world‎is chang‎i ng, he inevi‎t ably‎tells‎the story‎of DrReyno‎l ds. Dr Reyno‎l ds was a(n) ‎r from the big city. It seeme‎d as ifhe was in the newsp‎a per every‎day. My grand‎f athe‎r lived‎in a small‎outsi‎d e the city. This was at a time when such neigh‎b ourh‎o ods were still‎relat‎i vely‎new. Peopl‎e just could‎n't under‎s tand‎why anyon‎e would‎want to live so far from the city centr‎e.Howev‎e r, the neigh‎b ourh‎o od my grand‎f athe‎r lived‎in was growi‎n g every‎day. Many peopl‎ecould‎n't affor‎d to live in the city, and other‎s were tired‎of the crowd‎s. Cost and conge‎s tion‎compr‎i sed areal ‎s, a probl‎e m that has only gotte‎n worse‎with time. Large‎secti‎o ns of the urban‎‎g out of the city to the small‎e r towns‎. Along‎with these‎peopl‎e and their‎famil‎i es, compa‎n ies also start‎e d to reloc‎a te outsi‎d e major‎citie‎s. A great‎examp‎l e of this was Dr Reyno‎l ds.It is impos‎s ible‎to overs‎t ate the ‎f ican‎c e that Dr Reyno‎l ds' move had on my grand‎f athe‎r's town. Becau‎s e he was so famou‎s, there‎was obvio‎u sly a consi‎d erab‎l eamoun‎t of ‎i ated‎with his arriv‎a l. Howev‎e r, he quick‎l y showe‎d that hehad the skill‎s to back up his reput‎a tion‎. Dr Reyno‎l ds was not only a big,man who playe‎d footb‎a ll in his youth‎, but he also gradu‎a ted at the top of his class‎in medic‎a l schoo‎l.I'd be willi‎n g to ‎i ng thing‎shappe‎n ed in my grand‎f athe‎r's town. It must have been since‎he told the story‎so many times‎! DrReyno‎l ds' arriv‎a l ‎e d the dynam‎i cs of the town. It was no longe‎r "far away" from the city; it sudde‎n ly becam‎e "just outsi‎d e" the city limit‎s. Today‎, the world‎is chang‎i ng much faste‎r than can be measu‎r ed by the arriv‎a l of a big-city docto‎r in a small‎town. Who knows‎,maybe‎‎to tell my own grand‎c hild‎r en!Your answe‎r Corre‎c t answe‎r(31) emine‎n t emine‎n t(32) subur‎b subur‎b(33) curse‎curse‎(34) workf‎o rce workf‎o rce(35) magni‎t ude magni‎t ude(36) hype hype(37) brawn‎y brawn‎y(38) bet bet(39) funda‎m enta‎l ly funda‎m enta‎l ly(40) somed‎a y somed‎a yPart III: Readi‎n g Compr‎e hens‎i onQuest‎i ons 41 to 45 are based‎on the follo‎w ing passa‎g e.Somet‎i mes it seems‎we hear about‎the wonde‎r s of moder‎n techn‎o logy‎on a daily‎basis‎. I will admit‎that it's hard to argue‎with the facts‎. Compu‎t ers, autom‎o bile‎s, the Inter‎n et, and incre‎a sing‎l y small‎e r handh‎e ld devic‎e s certa‎i nly do make our lives‎more conve‎n ient‎. Every‎t hing‎, it seems‎, is getti‎n g faste‎r, light‎e r, cheap‎e r, and small‎e r. Prett‎y soon, compu‎t ers will be the size of iPods‎and iPods‎will be the size of finge‎r nail‎s.Techn‎o logy‎is makin‎g our lives‎more conve‎n ient‎, to be sure. But is it makin‎g our lives‎bette‎r? How depen‎d ent on these‎conve‎n ienc‎e s shoul‎d we becom‎e? How depen‎d ent have we alrea‎d y becom‎e? Insta‎n t commu‎n icat‎i on, video‎telep‎h ones‎, robot‎s, thous‎a nds of songs‎in the palm of your hand—all of these‎thing‎s are now avail‎a ble at your local‎shopp‎i ng centr‎e. Indee‎d, what was once consi‎d ered‎scien‎c e ficti‎o n now seems‎downr‎i ght plaus‎i ble. I can reali‎s tica‎l ly envis‎i on a world‎where‎liter‎a lly every‎t hing‎we do depen‎d s on a compu‎t er or a machi‎n e and, frank‎l y, it scare‎s me.Consi‎d er the follo‎w ing scena‎r io. Micha‎e l begin‎s his day by wakin‎g up to an elect‎r ic alarm‎clock‎. He gets dress‎e d and pours‎himse‎l f a cup of coffe‎e from a machi‎n e that is set to brew autom‎a tica‎l ly every‎morni‎n g. He walks‎to the corne‎r and board‎s a subwa‎y train‎for his commu‎t e to work. The train‎is contr‎o lled‎by a compu‎t er that knows‎how fast to go and when to slow down and stop. Micha‎e l enter‎s his offic‎e build‎i ng throu‎g h doors‎that "see" he is comin‎g and open for him. At work, Micha‎e l sits in front‎of a compu‎t er all day to do his job. He write‎s e-mails‎, updat‎e s a Websi‎t e, atten‎d s a video‎confe‎r ence‎onlin‎e, and makes‎telep‎h one calls‎. At night‎, he relax‎e s in front‎of the telev‎i sion‎(which‎has recor‎d ed all of his favou‎r ite shows‎), or he reads‎an e-book on his smart‎phone‎. How much of Micha‎e l's day is not depen‎d ent on compu‎t ers or machi‎n es? How much of this scena‎r io is unbel‎i evab‎l e? The answe‎r: none of it. It is a daily‎reali‎t y for many peopl‎e.Look aroun‎d you. Do you use a compu‎t er to send e-mails‎, write‎repor‎t s, do homew‎o rk, or searc‎h the Inter‎n et? What happe‎n s when that compu‎t er gets a virus‎or break‎s down? Most peopl‎e just sit there‎, baffl‎e d. They simpl‎y don't know what to do becau‎s e they don't know how the compu‎t er works‎. We depen‎d on compu‎t ers to make our lives‎easie‎r, and we depen‎d on compu‎t er techn‎i cian‎s to keep our compu‎t ersopera‎t iona‎l. The same can be said for nearl‎y any techn‎o logy‎. That's why engin‎e ers, compu‎t er profe‎s sion‎a ls, and techn‎o logy‎consu‎l tant‎s make such remar‎k able‎salar‎i es.The more we rely on techn‎o logy‎, the more we rely on speci‎a list‎s. The more we rely on speci‎a list‎s, the less respo‎n sibl‎e we feel to actua‎l ly know how to do somet‎h ing. This is a slipp‎e ry slope‎that will event‎u ally‎lead most peopl‎e to compl‎e te ignor‎a nce of how thing‎s work. It is ironi‎c, then, that the very techn‎o logi‎e s that are curre‎n tly toute‎d as the great‎e st advan‎c emen‎t s in human‎knowl‎e dge could‎ultim‎a tely‎have the exact‎oppos‎i te effec‎t.41. The write‎r of this passa‎g e would‎proba‎b ly agree‎with which‎of the follo‎w ing state‎m ents‎?A. Techn‎o logy‎is begin‎n ing to contr‎o l our lives‎.B. Compu‎t ers play a margi‎n al role in our socie‎t y.C. We rely on compu‎t er speci‎a list‎s becau‎s e they are conve‎n ient‎.D. Techn‎o logy‎is slowl‎y becom‎i ng more expen‎s ive.42. The write‎r's scena‎r io with Micha‎e l is prese‎n ted in order‎to _____‎.A. descr‎i be an innov‎a tion‎B. subst‎a ntia‎t e his argum‎e ntC. illus‎t rate‎an examp‎l e from a bygon‎e time.D. brag about‎perso‎n al accom‎p lish‎m ents‎43. Which‎parag‎r aph draws‎a perso‎n al analo‎g y to the reade‎r?A. Parag‎r aph 2.B. Parag‎r aph 3.C. Parag‎r aph 4.D. Parag‎r aph 5.44. Which‎of the follo‎w ing is the best one-sente‎n ce summa‎r y of this passa‎g e?A. Techn‎o logy‎makes‎our lives‎more conve‎n ient‎.B. Scien‎c e ficti‎o n is becom‎i ng a daily‎reali‎t y.C. Every‎b ody uses compu‎t ers and other‎techn‎o logi‎e s.D. The more we rely on techn‎o logy‎, the more helpl‎e ss we becom‎e.45. Which‎of the follo‎w ing event‎s does not suppo‎r t the write‎r's main idea?A. Marcu‎s plays‎the lates‎t video‎game after‎schoo‎l.B. Lisa reads‎a book befor‎e going‎to bed each night‎.C. Carol‎uses a GPS syste‎m to find her way in a new city.D. Tony blogs‎and sends‎e-mails‎from his mobil‎e phone‎.。

critical issues haveCritical Issues in EducationEducation is one of the most vital aspects of any society, as it lays the foundation for the development of individuals and the future of the country. However, there are several critical issues that have arisen in the field of education, which need to be addressed to ensure that all individuals receive a high-quality education.One of the most significant issues is the lack of resources, especially in underdeveloped and developing countries. Limited access to books, technology, and qualified teachers can prevent students from accessing information and knowledge that would enable them to succeed. This issue is further compounded by the digital divide, where students in rural areas or lower-income families may not have access to computers or the internet, leaving them at a disadvantage compared to their peers.Another critical issue is the need for more personalized learning experiences. As students come from diverse backgrounds with different learning styles and abilities, it is essential to provide them with an education that caters to their individual needs. This requires a shift away from the traditional one-size-fits-all approach to a more student-centered teaching method that allows students to explore their interests and develop their skills.Equity and access are also crucial issues in education. Many students are unable to access education due to factors such as poverty, discrimination, or social norms that prevent them from attending school. To address this issue, it is necessary to ensure that all students, regardless of their background, have equal access to education and are not discriminated against based on their identity or circumstances.Lastly, the issue of mental health and well-being in education cannot be overstated. The pressure of exams, expectations from parents and society, and other personal issues can lead to mental health issues among students. It is essential to provide support mechanisms such as counseling services and wellness programs tohelp students cope with these issues and ensure that they can thrive in their academic pursuits.In conclusion, there are several critical issues in education that need to be addressed. By investing in resources, personalizing learning experiences, ensuring equity and access, and promoting mental health and well-being, we can provide all individuals with a high-quality education that will enable them to reach their full potential.。

The Dilemma of Performance AppraisalPeter Prowse and Julie ProwseMeasuring Business Excellence,V ol.13 Iss:4,pp.69 - 77AbstractThis paper deals with the dilemma of managing performance using performance appraisal. The authors will evaluate the historical development of appraisals and argue that the critical area of line management development that was been identified as a critical success factor in appraisals has been ignored in the later literature evaluating the effectiveness of performance through appraisals.This paper willevaluatethe aims and methodsof appraisal, thedifficulties encountered in the appraisalprocess. It also re-evaluates the lack of theoretical development in appraisaland move from he psychological approachesof analysistoamorecritical realisation ofapproaches before re-evaluating the challenge to remove subjectivity and bias in judgement of appraisal.13.1IntroductionThis paper will define and outline performance management and appraisal. It will start by evaluating what form of performance is evaluated, then develop links to the development of different performance traditions (Psychological tradition, Management by Objectives, Motivation and Development).It will outline the historical development of performance management then evaluate high performance strategies using performance appraisal. It will evaluate the continuing issue of subjectivity and ethical dilemmas regarding measurement and assessment of performance. The paper will then examine how organisations measure performance before evaluation of research on some recent trends in performance appraisal.This chapter will evaluate the historical development of performance appraisal from management by objectives (MBO) literature before evaluating the debates between linkages between performance management and appraisal. It will outline the development of individual performance before linking to performance management in organizations. The outcomes of techniques to increase organizational commitment, increase job satisfaction will be critically evaluated. It will further examine the transatlantic debates between literature on efficiency and effectiveness in the North American and the United Kingdom) evidence to evaluate the HRM development and contribution of performance appraisal to individual and organizational performance.13.2 What is Performance Management?The first is sue to discuss is the difficulty of definition of Performance Management. Armstrong and Barron(1998:8) define performance management as: A strategic and integrated approach to delivering sustained success to organisations by Improving performance of people who work in them by developing the capabilities of teams And individual performance.13.2.1 Performance AppraisalAppraisal potentially is a key tool in making the most of an organisation’s human resources. The use of appraisal is widespread estimated that 80–90%of organizations in the USA and UK were using appraisal and an increase from 69 to 87% of organisations between 1998 and 2004 reported a formalperformance management system (Armstrong and Baron, 1998:200).There has been little evidence of the evaluation of the effectiveness of appraisal but more on the development in its use. Between 1998 and 2004 a sample from the Chartered Institute of Personnel and Development (CIPD, 2007) of 562 firms found 506 were using performance appraisal in UK.What is also vital to emphasise is the rising use of performance appraisal feedback beyond performance for professionals and managers to nearly 95% of workplaces in the 2004 WERS survey (seeTable 13.1).Clearly the use of Appraisals has been the development and extension of appraisals to cover a large proportion of the UK workforce and the coverage of non managerial occupations and the extended use in private and public sectors.13.2.2 The Purpose of AppraisalsThe critical issue is what is the purpose of appraisals and how effective is it ？Researched and used in practice throughout organizations? The purpose of appraisals needs to be clearly identified. Firstly their purpose. Randell (1994) states they are a systematic evaluation of individual performance linked to workplace behaviour and/or specific criteria. Appraisals often take the form of an appraisal interview,usually annual,supported by standardised forms/paperwork.The key objective of appraisal is to provide feedback for performance is provided by the linemanager.The three key questions for quality of feedback:1. What and how are observations on performance made?2. Why and how are they discussed?3. What determines the level of performance in the job?It has been argued by one school of thought that these process cannot be performed effectively unless the line manager of person providing feedback has the interpersonal interviewing skills to providethat feedback to people being appraised. This has been defined as the “Bradford Approach” which places a high priority on appraisal skills development (Randell, 1994). This approach is outlined in Fig. 13.1 whichidentifies the linkages betweeninvolving,developing, rewarding and valuing people at work..13.2.3 Historical Development of AppraisalThe historical development of performance feedback has developed from a range of approaches.Formal observation of individual work performance was reported in Robert Owens’s Scottish factory inNew Lanarkin the early 1800s (Cole, 1925). Owen hung over machines a piece of coloured wood over machines to indicate the Super intendent’s assessment of the previous day’s conduct (white forexcellent, yellow, blue and then black for poor performance).The twentieth centuryled to F.W. Taylor and his measured performance and the scientific management movement (Taylor, 1964). The 1930sTraits Approaches identified personality and performance and used feedback using graphic rating scales, a mixed standard of performance scales noting behaviour in likert scale ratings.This was used to recruit and identify management potential in the field of selection. Later developments to prevent a middle scale from 5 scales then developed into a forced-choice scale which forced the judgement to avoid central ratings.The evaluation also included narrative statements and comments to support the ratings (Mair, 1958).In the 1940s Behavioural Methods were developed. These included Behavioural Anchored Rating Scales (BARS); Behavioural Observation Scales (BOS); Behavioural Evaluation Scales (BES); critical incident;job simulation. All these judgements were used to determine the specific levels of performance criteria to specific issues such as customer service and rated in factors such asexcellent,average orneeds to improve or poor.These ratings are assigned numerical values and added to a statement or narrative comment by the assessor. It would also lead to identify any potential need for training and more importantly to identify talent for careers in linemanagement supervision and future managerial potential.Post1945 developed into the Results-oriented approaches and led to the development of management by objectives (MBO). This provided aims and specific targets to be achievedand with in time frames such as pecific sales, profitability,and deadlines with feedback on previous performance (Wherry, 1957).The deadlines may have required alteration and led to specific performance rankings of staff. It also provided a forced distributionof rankingsof comparative performance and paired comparison ranking of performance and setting and achieving objectives.In the 1960s the developmentof Self-appraisal by discussion led to specific time and opportunity for the appraisee to reflectively evaluate their performance in the discussion and the interview developed into a conversation on a range of topics that the appraise needed to discuss in the interview. Until this period the success of the appraisal was dependent on skill of interviewer.In the 1990s the development of 360-degree appraisal developed where information was sought from a wider range of sources and the feedback was no longer dependent on the manager-subordinate power relationship but included groups appraising the performance of line managers and peer feedback from peer groups on individual performance (Redman and Snape, 1992). The final development of appraisal interviews developed in the 1990s with the emphasis on the linking performance with financial reward which will be discussed later in the paper.13.2.4 Measures of PerformanceThe dilemma of appraisal has always to develop performance measures and the use of appraisal is the key part of this process. Quantitative measure of performance communicated as standards in the business and industry level standards translated to individual performance. The introduction of techniques such as the balanced score card developed by Kaplan and Norton (1992).Performance measures and evaluation included financial, customer evaluation, feedback on internal processes and Learning and Growth. Performance standards also included qualitative measures Which argue that there is an over emphasis on metrics of quantitative approach above the definitions of quality services and total quality management.In terms of performance measures there has been a transformation in literature and a move in the 1990s to the financial rewards linked to the level of performance.The debates will be discussed later in the paper.13.3 Criticism of AppraisalsCritiques of appraisal have continued as appraisal shave increased in use and scope across sectors and occupations. The dominant critique is the management framework using appraisal as an orthodox technique that seeks to remedy the weakness and propose of appraisals as a system to develop performance.This “orthodox” approach argues there are conflicting pur poses of appraisal (Strebler et al, 2001). Appraisal can motivate staff by clarifying objectives and setting clear future objectives with provision for training and development needs to establish the performance objective. These conflicts withassessing past performance and distribution of rewards based on past performance (Bach, 2005:301).Employees are reluctant to confide any limitations and concerns on their current performance as this could impact on their merit related reward or promotion opportunities(Newton and Findley, 1996:43).This conflicts with performance as a continuum as appraisers are challenged with differing roles as both monitors and judges of performance but an understanding counsell or which Randell(1994)argues few manager shave not received the raining to perform.Appraisal Manager’s reluctance to criticise also stems from classic evidence fromMcGregor that managers are reluctant to make an egative judgement on an individual’s performance a sit could be demotivating,leadto accusationsoftheirown supportand contributiontoindividual poor performance and to also avoid interpersonal conflict (McGregor, 1957).One consequence of this avoidance of conflict is to rate all criterion as central and avoid any conflict known as the central tendency.In a study of senior managers by Long neckeretal.(1987),they found organisational politics influenced ratings of 60 senior executives.The findings were that politics involved deliberate attempts by individuals to enhance or protect self-interests when conflicting courses of action are possible and that ratings and decisions were affected by potential sources of bias or inaccuracy in their appraisal ratings (Longeneckeret al., 1987).There are methods of further bias beyond Longenecker’s evidence. The polit ical judgements and they have been distorted further by overrating some clear competencies in performance rather than being critical across all rated competencies known as the halo effect and if some competencies arelower they may prejudice the judgment acrossthe positive reviews known as the horns effect (ACAS, 1996).Some ratings may only cinclude recent events and these are known as the recency effects. In this case only recent events are noted compared to managers gathering and using data throughout the appraisal period .A particular concern is the equity of appraisal for ratings which may be distorted by gender ,ethnicity and the ratings of appraisers themselves .A range of studies in both the US and UK have highlighted subjectivity in terms of gender (Alimo-Metcalf, 1991;White, 1999) and ethnicity of the appraise and appraiser(Geddes and Konrad, 2003). Suggestions and solutions on resolving bias will be reviewed later.The second analysis is the radical critique of appraisal. This is the more critical management literature that argues that appraisal and performance management are about management control(Newton and Findley, 1996;Townley, 1993). It argues that tighter management control over employee behaviour can be achieved by the extension of appraisal to manual workers, professional as means to control. This develops the literature of Foucault using power and surveillance. This literature uses cases in examples of public service control on professionals such a teachers (Healy, 1997) and University professionals(Townley, 1990).This evidence argues the increased control of public services using appraisal as a method of control and that the outcome of managerial objectives ignores the developmental role of appraisal and ratings are awarded for people who accept and embrace the culture and organizational values . However, this literature ignores the employee resistance and the use of professional unions to challenge the attempts to exert control over professionals and staff in the appraisal process (Bach, 2005:306).One of the different issues of removing bias was the use of the test metaphor (Folgeretal.,1992).This was based on the assumption that appraisal ratings were a technical question of assessing “true” performance and there needed to be increased reliability and validity of appraisal as an instrument to develop motivation and performance. The sources of rater bias and errors can be resolvedby improved organisational justice and increasing reliability of appraiser’s judgement.However there were problems such as an assumption that you can state job requirements clearly and the organization is “rational” with objectives that reflect values and that the judgment by appraisers’ are value free from political agendas and personal objectives. Secondly there is the second issue of subjectivity if appraisal ratings where decisions on appraisal are rated by a “political metaphor”(Hart le, 1995).This “political view” argues that a appraisal is often done badly because there is a lack of training for appraisers and appraisers may see the appraisal as a waste of time. This becomes a process which managers have to perform and not as a potential to improve employee performance .Organisations in this context are “political” and the appraisers seek to maintain performance from subordinates and view appraises as internal customers to satisfy. This means managers use appraisal to avoid interpersonal conflict and develop strategies for their own personal advancement and seek a quiet life by avoiding censure from higher managers.This perception means managers also see appraisee seeks good rating and genuine feedback and career development by seeking evidence of combining employee promotion and pay rise.This means appraisal ratings become political judgements and seek to avoid interpersonal conflicts. The approaches of the “test” and “political” metaphors of appraisal are inaccurate and lack objec tivity and judgement of employee performance is inaccurate and accuracy is avoided.The issue is how can organisations resolve this lack of objectivity?13.3.1 Solutions to Lack of Objectivity of AppraisalGrint(1993)argues that the solutions to objectivity lies in part with McGregor’s (1957) classic critique by retraining and removal of “top down” ratings by managers and replacement with multiple rater evaluation which removes bias and the objectivity by upward performance appraisal. The validity of upward appraisal means there moval of subjective appraisal ratings.This approach is also suggested to remove gender bias in appraisal ratings against women in appraisals (Fletcher, 1999). The solution of multiple reporting(internal colleagues, customers and recipients of services) will reduce subjectivity and inequity of appraisal ratings. This argument develops further by the rise in the need to evaluate project teams and increasing levels of teamwork to include peer assessment. The solutions also in theory mean increased closer contact with individual manager and appraises and increasing services linked to customer facing evaluations.However, negative feedback still demotivates and plenty of feedback and explanation by manager who collates feedback rather than judges performance andfail to summarise evaluations.There are however still problems with accuracy of appraisal objectivity asWalker and Smither (1999)5year studyof 252 managers over 5 year period still identified issues with subjective ratings in 360 degree appraisals.There are still issues on the subjectivity of appraisals beyond the areas of lack of training.The contribution of appraisal is strongly related to employee attitudes and strong relationships with job satisfaction(Fletcher and Williams, 1996). The evidence on appraisal still remains positive in terms of reinvigo rating social relationships at work (Townley,1993)and the widespread adoption in large public services in the UK such as the national health Service (NHS)is the valuable contribution to line managers discussion with staff on their past performance, discussing personal development plans and training and development as positive issues.One further concern is the openness of appraisal related to employee reward which we now discuss.13.3.2 Linking Appraisals with Reward ManagementAppraisal and performance management have been inextricably linked to employee reward since the development of strategic human resource management in the 1980s. The early literature on appraisal linked appraisal with employee control (Randell, 1994;Grint, 1993;Townley, 1993, 1999) and discussed the use of performance related reward to appraisals. However therecent literature has substituted the chapter titles employee “appraisal” with “performance management”(Bach, 2005; Storey, 2007) and moved the focus on performance and performance pay and the limits of employee appraisal. The appraisal and performance pay link has developed into debates to three key issues:The first issue is has performance pay related to appraisal grown in use?The second issue is what type of performance do we reward?and the final issue is who judges management standards?The first discussion on influences of growth of performance pay schemes is the assumption that increasing linkage between individual effort and financial reward increases performance levels. This linkage between effort and financial reward increasing levels of performance has proved an increasing trend in the public and private sector (Bevan and Thompson, 1992;Armstrong and Baron, 1998). The drive to increase public sector performance effort and setting of targets may even be inconsistent in the experiences of some organizational settings aimed at achieving long-term targets(Kessler and Purcell, 1992;Marsden, 2007). The development of merit based pay based on performance assessed by a manager is rising in the UK Marsden (2007)reported that the: Use of performance appraisals as a basis for merit pay are used in65 percent of public sector and 69 percent of the private sector employees where appraisal covered all nonmanagerial staff(p.109).Merit pay has also grown in use as in 1998 20% of workplaces used performance related schemes compared to 32% in the same organizations 2004 (Kersley et al., 2006:191). The achievements of satisfactory ratings or above satisfactory performance averages were used as evidence to reward individual performance ratings in the UK Civil Service (Marsden, 2007).Table 13.2 outlines the extent of merit pay in 2004.The second issue is what forms of performance is rewarded. The use of past appraisal ratings as evidence of achieving merit-related payments linked to achieving higher performance was the predominant factor developed in the public services. The evidence on Setting performance targets have been as Kessler (2000:280) reported “inconsistent within organizations and problematic for certain professional or less skilled occupations where goals have not been easily formulated”. There has been inconclusive evidence from organizations on the impact of performance pay and its effectiveness in improving performance. Evidence from a number of individual performance pay schemes report organizations suspending or reviewing them on the grounds that individual performance reward has produced no effect in performance or even demotivates staff(Kessler, 2000:281).More in-depth studies setting performance goals followed by appraisal on how well they were resulted in loss of motivation whilst maintaining productivity and achieved managers using imposing increased performance standards (Marsden and Richardson, 1994). As Randell(1994) had highlighted earlier, the potential objectivity and self-criticism in appraisal reviews become areas that appraisees refuse to acknowledge as weaknesses with appraisers if this leads to a reduction in their merit pay.Objectivity and self reflection for development becomes a weakness that appraises fail to acknowledge as a developmental issue if it reduces their chances of a reduced evaluation that will reduce their merit reward. The review of civil service merit pay (Makinson, 2000)reported from 4major UK Civil Service Agencies and the National Health Service concluded that existing forms of performance pay and performance management had failed to motivate many staff.The conclusions were that employees found individual performance pay divisive and led to reduced willingness to co-operate with management ,citing managerial favorites and manipulation of appraisal scores to lower ratings to save paying rewards to staff (Marsden and French, 1998).This has clear implications on the relationship between line managers and appraises and the demotivational consequences and reduced commitment provide clear evidence of the danger to linking individual performance appraisal to reward in the public services. Employees focus on the issues that gain key performance focus by focusing on specific objectives related to key performance indicators rather than all personal objectives. A study of banking performance pay by Lewis(1998)highlighted imposed targets which were unattainable with a range of 20 performance targets with narrow short term financial orientatated goals. The narrow focus on key targets and neglect of other performance aspects leads to tasks not being delivered.This final issue of judging management standards has already highlighted issues of inequity and bias based on gender (Beyer, 1990; Chen and DiTomasio, 1996; Fletcher, 1999). The suggested solutions to resolved Iscrimination have been proposed as enhanced interpersonal skills training are increased equitable use of 360 degree appraisal as a method to evaluate feedback from colleagues as this reduces the use of the “political metaphor”(Randell, 1994;Fletcher, 1999).On measures linking performance to improvement require a wider approach to enhanced work design and motivation to develop and enhance employee job satisfaction and the design of linkages between effort and performance are significant in the private sector and feedback and awareness in the public sector (Fletcher and Williams, 1996:176). Where rises be in pay were determined by achieving critical rated appraisal objectives, employees are less self critical and open to any developmental needs in a performance review.13.4 ConclusionAs performance appraisal provides a major potential for employee feedback that could link strongly to increasing motivation ,and a opportunity to clarify goals and achieve long term individual performance and career development why does it still suffers from what Randell describes as a muddle and confusion which still surrounds the theory and practice?There are key issues that require resolution and a great deal depends on the extent to which you have a good relationship with your line manager . Barlow(1989)argued `if you get off badly with your first two managers ,you may just as well forget it (p. 515).The evidence on the continued practice of appraisals is that they are still institutionally elaborated systems of management appraisal and development is significant rhetoric in the apparatus of bureaucratic control by managers (Barlow, 1989). In reality the companies create, review, change and even abolish appraisals if they fail to develop and enhance organisational performance(Kessler, 2000). Despite all the criticism and evidence the critics have failed to suggest an alternative for a process that can provide feedback, develop motivation, identify training and potential and evidence that can justify potential career development and justify reward(Hartle, 1997).绩效考核的困境Peter Prowse and Julie Prowse摘要本文旨在用绩效考核方法来解决绩效管理的困境。

Sepsis-induced myopathyLeigh Ann Callahan,MD;Gerald S.Supinski,MDAcquired weakness syndromes are a major cause of mortality and long-term morbidity in critically ill patients but thetrue occurrence rate and prevalence of these syndromes are not known (1–5).The classic descriptions of these syn-dromes have largely been based on elec-trophysiologic testing and defined by the presence of either a primary neuropathic process or a primary myopathic process,but it is now apparent that many patients who develop clinically recognizable weak-ness as a result of critical illness manifest findings consistent with both a neuropa-thy and a myopathy (1–6).Furthermore,a recent study examined muscle biopsies from a limited number of patients who were persistently weak after recovery from acute respiratory distress syndrome(7).Interestingly,all muscle biopsies were markedly abnormal,findings which could not be predicted based on the elec-trophysiologic diagnosis.As such,it re-mains unclear how to best diagnose inten-sive care unit (ICU)-acquired weakness because significant physiologic changes can develop in muscle without detectable electrophysiologic abnormalities.If these alterations occur in acutely ill patients in the ICU,it is reasonable to postulate that the prevalence of ICU-acquired myopathy may be much higher than previously re-ported.The major clinical findings in ICU-acquired weakness are limb muscle weak-ness and respiratory muscle weakness.Long-term consequences of peripheral muscle weakness include functional im-pairment,exercise limitation,and lower than normal health-related quality of life,sometimes persisting for years after dis-charge from the ICU (8–10).Importantly,the presence of respiratory muscle weak-ness results in prolonged duration of me-chanical ventilation,difficulty weaning patients from the ventilator,and recur-rence of respiratory failure after extuba-tion (11,12).Although successful wean-ing depends on a number of factors,it is ultimately the balance between the load imposed on the respiratory muscles caused by alterations in lung and chestwall mechanics (e.g.,increased airway re-sistance,decreased compliance)and the ability of the ventilatory pump to support this load that allows resumption of spon-taneous ventilation (13,14).Therefore,successful weaning is critically dependent on the strength and endurance of the respiratory muscles.Studies suggest that diaphragm fatigue does not contribute to weaning failure (15).However,when the respiratory muscles are weak,as is fre-quently the case,successful weaning can only occur when respiratory muscle strength and endurance improve.Clinical Assessment of Skeletal Muscle Strength in Critically Ill PatientsEarly clinical detection of either pe-ripheral and/or respiratory muscle weak-ness is difficult.The complexities in per-forming electrophysiologic testing include the requirement for neuromus-cular specialists with expertise in the technique,variabilities in interpretation of results,and technical limitations due to treatment modalities that may inter-fere with accurate placement of elec-trodes,such as wound dressings,arterial catheters,or peripheral edema (4).In ad-dition,for maximum reliability,testing requires patient cooperation.These fac-tors contribute to the lack of routine useFrom the Division of Pulmonary,Critical Care and Sleep Medicine,Department of Internal Medicine,Uni-versity of Kentucky,Lexington,KY.The authors have received funding from the Na-tional Institutes of Health (HL 080609and HL 069821to LAC;HL 080429,HL 081525,and HL 063698to GSS).The authors have not disclosed any potential con-flicts of interest.For information regarding this article,E-mail:lacall2@Copyright ©2009by the Society of Critical Care Medicine and Lippincott Williams &Wilkins DOI:10.1097/CCM.0b013e3181b6e439Sepsis is a major cause of morbidity and mortality in critically ill patients,and despite advances in management,mortality re-mains high.In survivors,sepsis increases the risk for the devel-opment of persistent acquired weakness syndromes affecting both the respiratory muscles and the limb muscles.This acquired weakness results in prolonged duration of mechanical ventilation,difficulty weaning,functional impairment,exercise limitation,and poor health-related quality of life.Abundant evidence indicates that sepsis induces a myopathy characterized by reductions in muscle force-generating capacity,atrophy (loss of muscle mass),and altered bioenergetics.Sepsis elicits derangements at multiple subcellular sites involved in excitation contraction coupling,such as decreasing membrane excitability,injuring sarcolemmal mem-branes,altering calcium homeostasis due to effects on the sar-coplasmic reticulum,and disrupting contractile protein interac-tions.Muscle wasting occurs later and results from increasedproteolytic degradation as well as decreased protein synthesis.In addition,sepsis produces marked abnormalities in muscle mito-chondrial functional capacity and when severe,these alterations correlate with increased death.The mechanisms leading to sep-sis-induced changes in skeletal muscle are linked to excessive localized elaboration of proinflammatory cytokines,marked in-creases in free-radical generation,and activation of proteolytic pathways that are upstream of the proteasome including caspase and calpain.Emerging data suggest that targeted inhibition of these pathways may alter the evolution and progression of sep-sis-induced myopathy and potentially reduce the occurrence of sepsis-mediated acquired weakness syndromes.(Crit Care Med 2009;37[Suppl.]:S354–S367)K EY W ORDS :sepsis;myopathy;critical illness;diaphragm;pe-ripheral muscles;mitochondria;contractile proteins;ICU-acquired weaknessof these techniques particularly because the availability of neurologists with this expertise is limited.As a result,electro-diagnostic testing is usually requested af-ter clinical recognition of weakness, which typically occurs late in the evolu-tion of the disease.Peripheral muscle involvement is usu-ally recognized clinically when patients are recovering from the acute phase of illness,and upon awakening,are noted to be weak.The severity of peripheral mus-cle weakness is widely variable and can be profound in some cases,manifesting symptoms of paralysis(16).The most widely used clinical tool to assess periph-eral muscle strength at the bedside is the Medical Research Council examination, which incorporates strength testing of three muscle groups in each limb with assignment of scores on a scale of1to5.A Medical Research Council score ofϽ48 is indicative of clinically significant weak-ness(11).Although it has been suggested that these measurements are reliable and reproducible,patients must be awake and fully cooperative.This restricts the utility of this tool in determining the presence of weakness,particularly early in the course of acute illness.Similarly,recognition of acquired re-spiratory muscle weakness most often oc-curs clinically when patients are difficult to wean from mechanical ventilation. Bedside assessment of respiratory muscle strength in critically ill patients typically involves measurements of maximal in-spiratory pressure generation and maxi-mal expiratory pressure generation(17). However,in mechanically ventilated pa-tients,measurements are often inaccu-rate because they are highly dependent both on the operator as well as the voli-tional effort of the patient.Even when standardized techniques are used by trained investigators,these measure-ments are unreliable(18).As a result,it is difficult,using these methods,to diag-nose acquired respiratory muscle weak-ness early in the course of critical illness.On the other hand,it is important to recognize that magnetic stimulation techniques are available to objectively measure respiratory muscle strength and peripheral muscle strength in critically ill mechanically ventilated patients(19). These techniques can be performed re-producibly without the limitation of an awake cooperative patient and also pro-vide the opportunity to detect early re-ductions in muscle strength.Several studies have utilized anterolateral mag-netic phrenic nerve stimulation to mea-sure diaphragm pressure generation inresponse to supramaximal twitch stimu-lation(T w P di)in mechanically ventilatedpatients in the ICU(15,20).In patientswho were thought to be ready for wean-ing from mechanical ventilation,Laghi etal found marked decrements in T w P di val-ues which averaged8to10cm H2O(15).Watson et al also measured T w P di in33critically ill mechanically ventilated pa-tients with a variety of diagnoses andduration of ventilation,and found valuesaveraged10.14cm H2O(20).These datareveal diaphragm strength is profoundlyreduced in critically ill patients,with val-ues averaging between23%and36%ofnormal(20,21).In addition,these stud-ies reported a wide range in the severityof respiratory muscle weakness withsome patients showing T w P di values aslow as1to2cm H2O(20).These nonvo-litional objective measurements have alsobeen used to assess peripheral musclestrength in a number of patient popula-tions including ICU patients.Harris et alassessed adductor pollicus strength in asmall group of critically ill patient andnoted severe peripheral muscle weakness,with values as low as30%of controls(22).Magnetic stimulation has also beenused to objectively measure the strengthof lower limb muscles(19,23).Use ofsuch techniques is therefore likely to pro-vide clinically relevant information re-garding the physiologic evolution ofweakness in critically ill patients,partic-ularly in the early stages of acute illness.Electrodiagnostic testing,use of theMedical Research Council examination,and measures of maximal inspiratorypressure and maximal expiratory pres-sure generation all require an awake co-operative patient,whereas magneticstimulation techniques provide objectivemeasurements of strength independentof these confounding variables.Nonethe-less,there has been a fair amount of in-terest in developing more simplified ap-proaches to assess weakness in criticallyill patients(24–26).Recently,it has beenargued that,because the therapeutic ar-mamentarium for ICU-acquired weaknessis virtually nonexistent,it is not essentialto make a precise physiologic diagnosis(24).On the other hand,it is important torealize that no study has systematicallyemployed objective nonvolitional func-tional measurements of muscle strengthto determine the prevalence or the timecourse of development of respiratorymuscle dysfunction and/or limb muscleweakness in critically ill patients.Emerg-ing data suggest that use of pharmaco-logic agents and other interventions mayvery well impact the occurrence and pro-gression of ICU-acquired weakness syn-dromes,and potentially improve recov-e of a simplistic,less sophisticatedapproach in clinical trials,however,isunlikely to result in sufficiently scientif-ically rigorous outcome measurementsthat would provide clear evidence as towhether or not these agents or interven-tions improve strength or prevent wast-ing.Furthermore,the fact that ourprogress in management and treatmentof these syndromes is in its infancy pro-vides a strong rationale for an approachthat systematically incorporates both theavailable scientific evidence and best di-agnostic tools to critically address theseissues,rather than retreating to simplis-tic tactics.Failure to use more sophisti-cated methods may very well impede ad-vancements in understanding anddevelopment of effective treatments forcritical care-acquired weakness.Sepsis Is a Major Risk forAcquired Weakness in CriticallyIll PatientsAlthough a number of factors havebeen associated with prolonged weaknessin critically ill patients,sepsis(includingseptic shock,systemic inflammatory re-sponse syndrome of infectious and non-infectious etiologies,multiple organ fail-ure)is a major risk(4,27).AlthoughBolton et al(28)were thefirst to suggestthat critical illness-acquired weaknesssyndromes were associated with sepsis,systemic inflammatory response syn-drome,and multiple organ failure,addi-tional prospective and retrospective clin-ical studies confirm this observation(29–31).Importantly,the reported frequencyof prolonged weakness in sepsis is ex-tremely high,occurring in70%to100%of these patients(29–31).Furthermore,these studies provide clear evidence thatsepsis produces profound decrements inboth limb and respiratory muscle func-tion.In the last decade,much attention hasfocused on studies showing that mechan-ical ventilation per se induces deleteriouseffects on the diaphragm(32–35).How-ever,the clinical importance of ventila-tor-induced diaphragm dysfunction andits relationship to ICU-acquired weaknessis still unclear.For example,ventilator-induced diaphragm dysfunction does notproduce peripheral muscle weakness (36).Furthermore,the mode of ventila-tion is a major factor in producing ven-tilator-induced diaphragm dysfunction (37–39).Although Levine et al elegantly validated that diaphragm atrophy devel-ops in brain dead patients who were me-chanically ventilated using a controlled mode(32),this study did not include assessments of diaphragm strength.In addition,an international survey sug-gested that controlled mechanical venti-lation is not commonly used in the ICU (40).Finally,if mechanical ventilation is the major cause of respiratory muscle weakness in critically ill patients,venti-latory support theoretically would pro-hibit successful weaning in any patient who requires mechanical ventilation be-cause of persistent ongoing respiratory muscle injury.As such,more studies are required to address the importance of ventilator-induced diaphragm dysfunc-tion in patients and its relationship to ICU-acquired weakness.In contrast,both animal and human data showed that sep-sis-induced respiratory and limb muscle weakness is a major risk for development of ICU-acquired weakness. Manifestations of Sepsis-Induced MyopathyThere is abundant scientific evidence that sepsis induces a myopathy character-ized by reductions in force-generating ca-pacity,atrophy(loss of muscle mass),and altered bioenergetics.A variety of animal models including cecal ligation perfora-tion(CLP),endotoxin administration, live bacteria injection,pneumonia,and cytokine induction have been used to as-sess skeletal muscle function in sepsis. Interestingly,most functional assess-ments of skeletal muscle in sepsis have examined the respiratory muscles;fewer data exist for limb muscles.The following sections will review the manifestations of sepsis-induced changes in muscle. Sepsis Reduces SkeletalMuscle-Specific Force GenerationIt is important to understand that muscle strength is dependent on two fac-tors:muscle force generation for a given amount of muscle mass and total muscle mass.These factors represent two dis-tinct aspects of muscle function and can alter muscle strength independently of each other.This is a critical concept be-cause the processes that regulate andmodulate muscle force generation for agiven amount of muscle mass(force percross-sectional area)and the processesthat regulate and modulate total musclemass are different.Most of the studiesdescribed in this section evaluated phys-iologic function in muscle by assessingmuscle-specific force generation,a mea-sure of muscle strength where force isnormalized to muscle cross-sectionalarea,thereby taking into account anychanges in muscle mass.Furthermore,muscle wasting can occur without pro-ducing changes in muscle-specific forcegeneration.For example,in a model ofprolonged nutritional deprivation,Lewiset al showed that diaphragm mass wasreduced by50%,but diaphragm-specificforce generation was normal(41).In ad-dition,Le Bourdelles et al showed thatafter48hrs of mechanical ventilation,limb muscle mass is reduced significantlywithout concomitant reductions in limbmuscle-specific force generation(36).Therefore,although force reductions andmuscle wasting often occur simulta-neously,it is important to understandthat reductions in muscle-specific forcegeneration may exist in the absence ofatrophy and atrophy may occur withoutreducing muscle-specific force genera-tion.Likewise,enhancing muscle massdoes not necessarily improve muscle-specific force generation,as demon-strated in studies that assessed musclecontractile performance in myostatinknockout animals(42).Finally,experi-mental evidence suggests that pharmaco-logic interventions can differentially af-fect muscle-specific force generation andwasting(43,44).In one of thefirst studies evaluatingrespiratory muscle contractile perfor-mance in sepsis,Hussain et al showedthat injection of Escherichia coli endo-toxin in spontaneously breathing dogs in-duced hypercapneic respiratory failure(45).Subsequently,a number of investi-gators demonstrated that diaphragm con-tractile performance is profoundly re-duced in several different animal modelsof sepsis and infection,including CLP,endotoxin administration and pneumonia(46–53)(Fig.1).Declines in respiratorymuscle strength occur within hours ofinduction of sepsis and are rapidly pro-gressive.Importantly,these decrementsin diaphragm-specific force generation(force normalized per muscle cross-sectional area)occur before any evidenceof reductions in diaphragm mass or dia-phragm protein content(54).Similar data indicate that sepsis alsoalters peripheral muscle-specific forcegeneration.Supinski et al examined theeffects of varying doses of endotoxin andobservedϾ50%reductions in force-generating capacities of both the dia-phragm and limb muscles(55)(Fig.2).Recently,Eikermann et al examined forcegeneration and fatiguability in the adduc-tor pollicus muscle of critically ill septicpatients,comparing these functional pa-rameters in patients with normal individ-uals before and after cast immobilization(56).Importantly,2wks of lower armimmobilization had no effects on forcegeneration in controls,but forcegenera-Figure 1.Diaphragm force-frequency relation-ships in endotoxin-treated animals.Diaphragmforce-frequency curves for control(E)and low(F),medium(Œ),and high(f)dose endotoxingroups.As shown,endotoxin elicited a dose-dependent reduction in respiratory muscle-specific force generation.*Control group signif-icantly different from the three endotoxingroups.Modified and reproduced with permis-sion from Supinski et al(55).Figure2.Limb muscle force-frequency relation-ships in endotoxin-treated animals.Limb muscle(flexor hallucis longus)force-frequency relation-ships for control(E)and low(F),medium(Œ),and high(f)dose endotoxin groups.Endotoxinreduced limb muscle-specific force generation ina dose-dependent fashion.*Control group signif-icantly different from the three endotoxingroups;#control group significantly differentfrom low and high endotoxin dose groups;**con-trol group significantly different from low endo-toxin dose group.Modified and reproduced withpermission from Supinski et al(55).tion was severely reduced in septic pa-tients (Fig.3).In contrast,pneumonia markedly im-pairs diaphragm force generation,but pe-ripheral muscle force is preserved (51).Likewise,cardiac specific overexpression of tumor necrosis factor (TNF)-␣reduces diaphragm strength without altering limb muscle function (57).Studies also indicate that sepsis induces more abun-dant cytokine levels in the diaphragm compared with limb muscle,raising the question as to whether or not the respi-ratory muscles are more susceptible to sepsis-induced injury (58).If this is true,it is conceivable that respiratory muscle weakness may represent the earliest man-ifestation of sepsis-induced myopathy.Sepsis Reduces Skeletal Muscle MassThe earliest important physiologic al-teration in response to acute sepsis is a reduction in muscle-specific force-gener-ating capacity.However,in more pro-longed models of sepsis,muscle wasting is a prominent feature and is thought to result from increased proteolysis and de-creased protein synthesis.A number of recent reviews have highlighted the cur-rent knowledge regarding the mecha-nisms underlying muscle atrophy in a variety of conditions including sepsis (59–63).For example,in the CLP model,data indicate that limb muscle protein content diminishes due to increased pro-teolysis (64).Rossignol et al also found reductions in limb muscle force genera-tion and mass,using a prolonged model of CLP (65).Wasting also occurs in both respiratory and limb muscles with pro-longed endotoxemia (66,67)and in other models of protracted infection (68).Al-though experimental models of pneumo-nia have not completely addressed atro-phy and protein loss,Langen et al described significant muscle wasting and impaired muscle regeneration in a trans-genic mouse model of chronic pulmonary inflammation (69).These data,therefore,provide evidence that loss of muscle mass is also an important aspect of sepsis-induced muscle weakness.Sepsis Alters Skeletal Muscle BioenergeticsAlterations in mitochondrial bioener-getic function are thought to play a crit-ical role in sepsis-induced organ failure and there are a number of recent reviews on this topic (70–75).Both human and animal data indicate that sepsis inducesmitochondrial dysfunction in respiratory and limb muscles,and these alterations are thought to be important in the patho-genesis of sepsis-induced muscle dys-function.Brealey et al demonstrated de-creased respiratory chain complex I activity and lower adenosine triphosphate (ATP)levels in skeletal muscle biopsies taken from critically ill patients in septic shock (76).Furthermore,they showed a significant correlation between muscle mitochondrial dysfunction and death in sepsis.In follow-up studies,this group reported similar alterations in complex I activity and ATP levels in hind-limb mus-cle of rodents as well as significant dec-rements in bioenergetics in other tissues (77).Interestingly,they also demon-strated that,despite severe metabolic dis-turbances in muscle,gross histologic damage or evidence of cell death is ab-sent;this underscores the importance of performing physiologic assessments when evaluating the effects of sepsis in muscle.Although bioenergetic function in sepsis is markedly abnormal,the ex-tent to which these mitochondrial de-rangements participate in the develop-ment and progession of sepsis-induced prolonged ICU-acquired weakness,or in the recovery process,however,are yet to be determined.Subcellular Sites of Skeletal Muscle Dysfunction in SepsisSepsis-induced myopathy may produce muscle dysfunction by effecting a number of sites involved in excitation contraction coupling including the sarcolemma,the sarcoplasmic reticulum,the contractile ap-paratus,and the mitochondria.SarcolemmaMuch attention has been given to the discovery that muscle becomes electri-cally inexcitable during the development of acquired weakness in critically ill pa-tients (78–81).This has led to the con-cept that ICU-associated weakness repre-sents an acquired channelopathy involving dysregulation of sodium chan-nels.It is important to note,however,that much of these data with respect to critical illness myopathy has been gener-ated in animal models using denervation with concomitant administration of high-dose steroids and should not be extrapo-lated to sepsis.However,Rossignol et al recently showed evidence of decreased muscle membrane excitability andup-Figure 3.Force-frequency relationships in patients with sepsis and multiple organ failure.Force-frequency curves of adductor pollicis muscle during supramaximal ulnar nerve stimulation before performing the fatigue protocol (mean Ϯstandard deviation).Force is significantly lower in patients with sepsis and multiple organ failure (full circles ;n ϭ13)compared with healthy volunteers (triangles ;n ϭ7)both before (open triangles )and after (solid triangles )2wks of immobilization of their lower arm and thumb.*p Ͻ.01vs.volunteers before and after immobilization;#p Ͻ.05vs.volunteers before immobilization.These data indicate that sepsis significantly reduced muscle force generation in peripheral muscle whereas immobilization had no effect.Reproduced with permission from Eikermann et al (56).regulation of Nav 1.5in a chronic sepsis model,corroborating findings in the dener-vation steroid model (82).Additional stud-ies will be needed to determine whether this process plays a central role in the pathogenesis of sepsis-induced myopathy.On the other hand,there is clear evi-dence that sepsis causes marked sar-colemmal injury in muscles (83–85).Us-ing a fluorescent tracer dye (procion orange)which does not enter cells with intact membranes,Lin et al found that diaphragm myofibers of both lipopolysac-charide treated and CLP animals demon-strated a markedly greater level of sar-colemmal damage than in control animals (83)(Fig.4).In addition,sar-colemmal damage also increased in the soleus muscles of the CLP group.Fur-thermore,these alterations were linked to excessive nitric oxide generation and alterations in diaphragm myofiber mem-brane potential (83).Importantly,insti-tution of mechanical ventilation in septic animals prevented sarcolemmal damage in the diaphragm (84),suggesting that mechanical ventilation under these con-ditions was not harmful but,in fact,pro-tective.Although it is not known if sepsis-induced sarcolemmal injury occurs in pa-tients,this is nevertheless an important issue to consider.For example,the ben-eficial effect of exercise on skeletal mus-cle are well described;however,exercise increases cytokines and free-radical gen-eration in muscle (86).In addition,Du-mont et al recently showed that reloading muscles induces inflammatory cell infil-tration and worsens sarcolemmal injury (87).As a result,it is conceivable that exercising patients with damaged mus-cles could potentially propagate muscle inflammation and injury,or delay recov-ery.Such issues should be carefully ex-amined in the context of early mobiliza-tion and exercise interventions,and particularly in patients with sepsis-induced acquired weakness.Sarcoplasmic ReticulumThe skeletal muscle ryanodine recep-tor (RyR1)is a highly redox-senstive ion channel,modulated by hydrogen perox-ide and nitric oxide (NO)under physio-logic conditions (88–90).However,a number of studies suggest that resting intracellular calcium (Ca ϩϩ)levels are increased in muscle in sepsis,and al-though most studies have examined this issue in cardiac muscle,there are data for skeletal muscle.For example,Benson et al showed that Ca ϩϩuptake and content in limb skeletal muscle are increased dur-ing sepsis and that these high Ca ϩϩcon-centrations are critically involved in reg-ulation of muscle protein breakdown in sepsis (91).On the other hand,Liu inves-tigated the in vivo effects of lipopolysac-charide on the Ca ϩϩ-dependent mechan-ical activity and ryanodine response in isolated sarcoplasmic reticulum mem-brane vesicles from the mouse dia-phragm,demonstrating that Ca ϩϩre-lease and [3H]ryanodine binding in sarcoplasmic reticulum membrane vesi-cles of lipopolysaccharide-treated animals were significantly depressed (92)(Fig.5).Taken together,these data suggest that complex alterations in calcium ho-meostasis are present in septic skeletal muscle,with evidence that calcium in-creases in some subcellular compart-ments and decreases in others.Additional data will be needed to determine whether sarcoplasmic reticulum alterations are important in the pathogenesis of sepsis-induced myopathy and ICU-acquired weakness.Contractile ProteinsOne mechanism by which sepsis re-duces skeletal muscle force generation in sepsis is by directly alteringcontractileFigure 4.Sepsis induces skeletal muscle sarcolem-mal injury.Representative micrographs illustrating the effects of sepsis on sarcolemmal integrity in the diaphragm.a ,Control group.Very little tracer dye uptake within individual myofibers was found,al-though intense staining of extracellular connective tissue indicates good dye diffusion throughout the tissue.b ,Lipopolysaccharide group.Note the pres-ence of numerous myofibers with sarcolemmal damage,as indicated by their inability to prevent entry of the low molecular weight tracer dye.c ,Cecal ligation perforation group.Myofibers with sarcolemmal damage are characterized by variable degrees of intracellular fluorescent staining,similar to the findings in the lipopolysaccharide group.Reproduced with permission from Lin et al(83).Figure 5.Sepsis induces alterations in skeletal muscle sarcomplasmic reticulum calcium han-dling.Ca2ϩrelease and [3H]ryanodine binding were studied using sarcoplasmic reticulum mem-brane vesicles isolated from skeletal muscles of control and lipopolysaccharide (LPS )(7.5mg/kg)-treated animals.Some rats were pretreated with polymyxin B (PMB ),the polycationic anti-biotic that neutralizes LPS before the application of LPS.A )Ryanodine (2␮M)-induced Ca2ϩre-lease from sarcoplasmic reticulum was signifi-cantly reduced in muscles from LPS-treated an-imals compared with controls.B )[3H]ryanodine binding was also significantly reduced in animals treated with LPS.Pretreatment with polymyxin B abated LPS-induced changes in Ca2ϩrelease and [3H]ryanodine binding.Data are presented as mean Ϯstandard error of the mean.*p Ͻ.05as compared with control;**p Ͻ.05as compared with LPS group.Reproduced with permission from Liu et al (92).。

CRITICAL ANALYSISA critical analysis paper asks the writer to make an argument about a particular book, essay, movie, etc. The goal is two fold: one, identify and explain the argument that the author is making, and two, provide your own argument about that argument. One of the key directions of these assignments is often to avoid/minimize summary – you are not writing a book report, but evaluating the author’s argument.Potential points of criticismSometimes it can seem intimidating to “criticize” a b ook or article; after all, they are professors and experienced policymakers. However, part of this exercise is to expose the fact that even though these authors are highly qualified, they are still advancing an argument and providing evidence--their aim is to persuade you that their argument is true, not to just present facts. Once you recognize that these authors are making arguments, you can analyze whether or not you find their argument compelling. Following are some possible questions you could ask to evaluate arguments:• Theoretical questions – How does the author understand the situation? What is his/her theoretical background? How would this influence their view of the situation?• Definitional questions - Are all the concepts in the text clear? Does the author define a concept vaguely to allow it to travel across different situations? If a concept can relate two seemingly different situations, is the concept meaningful?• Evidence questions:- Does the author’s evidence support their argument? Do they have enough specific evidence to prove the more general point?- Does the author under-emphasize or ignore evidence that is contrary to their argument? - Is the evidence credible? Can you identify a bias in the evidence?Was the study done by a political action committee, and environmental NGO, or a non- partisan research group? How might a group affiliation or funding influence the outcome of research?• Implication/Policy relevance questions – What are the implications of this argument? Are those implications positive or negative? How has the author dealt with this issue? • Other approaches:Is the author’s argument consistent throughout the book? Or, does the conclusion seem to offer a different argument than he/she presented in the introduction?Does the author’s background have important implications for their argument?Do the specific language choices of the author betray a certain ideology or bias, or frame the argument in a certain way?Structuring a Critical Analysis PaperMost critical analysis papers begin with a short summary of the work and then dive in to the argument. Since most of these paper assignments are short, it is important to be concise in all parts of your analysis. Writing an outline (and following it) is crucial to remain focused on your argument and avoid summary or irrelevant description. Following is a sample outline for a critical analysis paper:I. Introductiona. Identify the work being criticizedb. Present thesis – argument about the workc. Preview your argument – what are the steps you will take to prove yourargumentII. Short summary of the worka. Does not need to be comprehensive – present only what the reader needs toknow to understand your argumentIII. Your argumenta. Your argument will likely involve a number of sub-arguments –mini-theses youprove to prove your larger argument true. For example, if your thesis was that the author’s presumption that the world will soon face a “clash of civilizations” isflawed because he inadequately specifies his key concept, civilizations, you might prove this by:i. Noting competing definitions of civilizationsii. Identifying how his examples do not meet the example of civilizationsiii. Argue that civilization is so broad and non-specific that it is not usefulb. This should be the bulk of the paper – Your professor wants to read yourargument about the work, not a summary.IV. Conclusiona. Reflect on how you have proven your argument.b. Point out the importance of your argumentFinal Reminders• Even though you are potentially only referring to one source, you still need to cite your information, using either parenthetical citation or footnotes/endnotes.• Double check the assignment to make sure you have covered all the points that yourprofessor has asked.。