Influence of Host Tree Condition on the Performance of Tetropium fuscum (Coleoptera: Cerambycidae)
Author(s): Leah Flaherty, Jon D. Sweeney, Deepa Pureswaran, and Dan T. Quiring Source: Environmental Entomology, 40(5):1200-1209. 2011.
Published By: Entomological Society of America
DOI: https://www.doczj.com/doc/c114484221.html,/10.1603/EN11114
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P LANT-I NSECT I NTERACTIONS
In?uence of Host Tree Condition on the Performance of Tetropium fuscum(Coleoptera:Cerambycidae)
LEAH FLAHERTY,1,2,3JON D.SWEENEY,3DEEPA PURESWARAN,4AND DAN T.QUIRING1
Environ.Entomol.40(5):1200D1209(2011);DOI:https://www.doczj.com/doc/c114484221.html,/10.1603/EN11114 ABSTRACT Tetropium fuscum(F.)attacks weakened Norway spruce,Picea abies(L.)Karst.,in its native Europe and may colonize healthy spruce in Nova Scotia,Canada.We used manipulativeTeld experiments to evaluate:1)the development of T.fuscum on apparently healthy red spruce(Picea rubens Sarg.)in Nova Scotia;2)the in?uence of red spruce physiological condition(healthy,girdled or cut)on T.fuscum performance;and3)the impact of natural enemies and competitors on T.fuscum performance when developing on trees of varying condition.Tetropium fuscum successfully developed on healthy red spruce.Survival was higher on healthy than on girdled or cut trees when larvae were exposed to natural enemies and competitors.The beneTts of reduced competition and parasitism on healthy trees appeared to compensate for any reductions in nutritional quality,increase in host resistance,or both.In contrast,when T.fuscum were protected from natural enemies,apparent survival was highest on girdled trees.Tetropium fuscum development took longer on healthy than on cut or girdled trees,and emerged adults were largest on healthy trees.The disparities in adult sizes among the three treatments may mean that healthy trees are more nutritious.Alternatively,the differences may indicate that a greater amount of time was spent feeding in healthy than in girdled or cut trees. Tree condition appears to have a direct impact on the success of T.fuscum,in?uencing survival, development time,and adult size,and may mediate the impact of natural enemies and competitors, further affecting T.fuscum performance.
KEY WORDS Cerambycidae,development time,tree condition,tree moisture stress
The physiological condition of the host plant on which an insect herbivore develops can have a large impact on itsTtness(Koricheva and Larsson1998).For ex-ample,drought stress may promote outbreaks of her-bivorous insects(Mattson and Haack1987a),and her-bivore abundance and performance often vary with host plant growth rate(Quiring et al.2006).Variations in herbivore performance on host plants of varying condition may be caused directly by quantitative or qualitative variation in herbivore nutrition(Hodges and Lorio1969,White1984);by host plant resistance to attack,or both(Christiansen et al.1987);or indi-rectly because host plant condition may mediate the impact of natural enemies(Shibata2000,Paine et al. 2001)and competitors(Ohgushi2005).Thus,many insect herbivores are adapted to colonize hosts of a particular physiological condition,which is often as-sociated with their feeding guild(Larsson1989).Some species,most notably galling and chewing insects,of-ten attack vigorous host plants(Price1991),whereas others,like many bark and wood-boring beetles,more frequently attack stressed,dying,or dead hosts(Paine et al.1997,Hanks1999).
Tetropium fuscum(F.)(Coleoptera:Cerambyci-dae)is native to most of Europe,except the far west (Juutinen1955);it commonly attacks weakened or recently killed Norway spruce,Picea abies(L.)Karst., and is not considered an important pest species (Schimitschek1929,Juutinen1955).In Novia Scotia, Canada,where T.fuscum has been established since at least1990(Smith and Hurley2000),slow-growing red spruce,Picea rubens(Sarg.),appear to be more sus-ceptible to colonization by T.fuscum than faster grow-ing trees(O?Leary et al.2003).However,T.fuscum has been observed to colonize and kill apparently healthy spruce(Smith and Humble2000)and is consequently classiTed as a quarantine pest.
In its native range,T.fuscum typically has one gen-eration a year,and may take2yr to develop in cooler climates(Schimitschek1929,Juutinen1955).In Nova Scotia,sexually mature adult T.fuscum emerge from trees in late May to mid-August.They mate soon after emerging and have not been observed to feed.Mated females deposit eggs in bark crevices,and at20?C,eggs take?12d to hatch(Schimitschek1929,Juutinen 1955).Neonate larvae bore through the bark into the phloem,where they feed and create a network of
1Population Ecology Group,Faculty of Forestry and Environmen-
tal Management,University of New Brunswick,Fredericton,New Brunswick,E3B6C2,Canada.
2Corresponding author,e-mail:leahelizabeth?aherty@https://www.doczj.com/doc/c114484221.html,.
3Natural Resources Canada,Canadian Forest Service-Atlantic Forestry Centre,P.O.Box4000,Fredericton,New Brunswick,E3B
5P7,Canada.
4Natural Resources Canada,Canadian Forest Service-Lauren-
tian Forest Centre,1055du P.E.P.S.,Sainte-Foy Quebec,G1V4C7, Canada.
0046-225X/11/1200D1209$04.00/0?2011Entomological Society of America
galleries(Schimitschek1929,Juutinen1955).Prepu-pal larvae usually build pupal cells in fall,located at the phloemDsapwood interface or up to4-cm deep in the sapwood,and pupate in spring(Schimitschek1929). The apparent discrepancy in the condition of trees reported as susceptible to attack by T.fuscum in its native versus introduced range stimulated this re-search because the level of risk associated with this exotic beetle depends on its ability to attack and kill healthy trees.In this study,we used manipulativeTeld experiments to evaluate:1)the development of T. fuscum on apparently healthy red spruce trees in Nova Scotia;2)the in?uence of red spruce physiological condition(i.e.,growth rate and moisture stress)on T. fuscum performance;and3)the impact of natural enemies and competitors on T.fuscum performance when developing on red spruce of varying condition. We also tested the assumption that when adults are forced to oviposit on a particular host tree,a similar number of eggs will be laid regardless of tree condi-tion.
We hypothesized that moisture-stressed,slow-growing red spruce trees have reduced resistance to T. fuscum attack and contain higher or more balanced levels of nutrients for developing T.fuscum larvae than healthy trees(White1984,Mattson and Haack1987a). Conversely,we hypothesized that interspeciTc com-petition is greater in stressed than in healthy trees because the former are more commonly colonized by phloeophagous beetles,such as Tetropium cinnam-opterum Kirby and Dendroctonus ru?pennis(Kirby) (Coleoptera:Curculionidae)(Drooz1985).We also expected that natural enemies would forage more fre-quently on stressed than on healthy trees because of their greater likelihood ofTnding host insects and, therefore,predicted that when larvae are protected from natural enemies and native bark beetles,T.fus-cum performance would be greater on stressed than on healthy trees.However,when larvae are exposed to natural enemies and competitors,we predicted that mortality from natural enemies and competition would be greater on stressed than on healthy trees.
Materials and Methods
Description of Site and Tree Manipulation.In May 2008,we selected60apparently healthy,dominant or co-dominant red spruce trees(20D28cm diameter at breast height[DBH])with full green crowns near EnTeld,Nova Scotia,Canada(44?54.226?N,063?91.970?W)in a mature(?65-yr-old),red spruce-dominated mixed-wood stand.This stand was within the area currently infested by T.fuscum.We randomly assigned each tree to one of three host conditions: healthy,girdled,or cut(20trees per tree condition). On22May,the bark,phloem,and sapwood of girdled trees were cut to a depth of?2.5cm with a chainsaw, 30cm above the tree base.On27May,we felled20 trees,and took a2.4-m log from the base of each tree to serve as the“cut”treatment sample.Healthy trees were not manipulated.To evaluate whether the above-described treatments resulted in trees of vary-ing physiological condition,we measured moisture stress and current-year terminal shoot length of healthy and girdled trees.As the cut treatment was a log,detached from the roots and crown of the tree,we assumed it represented the least vigorous tree condi-tion.
Tree moisture stress was measured using a PMS Pressure Chamber Instrument(model610,PMS In-strument Company,Albany,OR)4wk after adult T. fuscum were caged on trees(see Effect of Tree Con-dition and Caging on T.fuscum Performance).As the oviposition period is?14d and eggs take10D14d to hatch(Juutinen1955),this represents the approxi-mate time of larval establishment.We used pole-prun-ers to cut an exposed midcrown branch and randomly selected two distal-lateral shoots.Shoots were cut so that only foliage from2007and2008remained.We removed the bark and phloem from the cut end of each shoot,extending1D2mm,and placed the shoot in a sealed pressure chamber with the cut end ex-posed.Pressure was applied to the shoot,and we noted the pressure required to force water up the water column,which was apparent by water appearing at the cut surface.Time of day was also recorded for each measurement.Tree condition treatment(F
1,37
?14.1;
P?0.001),but not time of day(F
1,37
?1.5;P?0.23), in?uenced tree moisture stress(analysis of covariance (ANCOVA)).Mean(?SE)moisture stress was sig-niTcantly higher on girdled(294?24psi)than on healthy(197?13psi)trees.
We measured current-year terminal shoot length on a subsample of10healthy and10girdled trees in November2008.Shoots on girdled trees(18?8mm), which experienced higher levels of moisture stress, grew signiTcantly less than shoots on healthy trees
(125?14mm)(two-tailed t-test,T
1,18
?6.9;P?0.001),supporting our assumption that trees in the three treatments represent a range of physiological conditions.
Effect of Tree Condition and Caging on T.fuscum Performance.Fine-mesh(opening?0.3mm2)cages (125-cm circumference by35cm high)were fastened around the bole of each tree,entirely enclosing a 30-cm-long section,40D70cm above the tree base. Cages were tied around the bole of each tree with drawstrings that were sewn into each125-cm edge, and Velcro fasteners(along the entire vertical35-cm edges)sealed cages together.We placed polyurethane foam between the drawstrings and tree bark to ensure a tightTt.Availability of adult T.fuscum prevented a single release date,so three mated T.fuscum pairs were placed in cages on10randomly selected trees per treatment(30trees)during theTrst week of June 2008,and on the remaining trees during the third week of June2008.Cages were fastened to trees just before T.fuscum manipulation.All T.fuscum used in this experiment were reared in the Atlantic Forestry Cen-tre?s containment laboratory(Natural Resources Can-ada,Fredericton,NB,Canada),from bolts cut from infested trees near Halifax,Nova Scotia.
To determine the effects of tree condition on T. fuscum mortality in the absence and presence of nat-
October2011F LAHERTY ET AL.:E FFECT OF H OST C ONDITION ON T.fuscum P ERFORMANCE1201
ural enemies,we removed the cages from half of the trees in each treatment after14d,the typicalTeld oviposition period(Juutinen1955),whereas all other cages remained on the tree for the duration of the experiment.
Tetropium fuscum larvae developed in trees through-out summer and we cut exploited portions of each tree into bolts in late October.We stored bolts at the stand boundary until15December to ensure that a sufTcient cold period had elapsed to satisfy larval diapause re-quirements(J.S.,unpublished data)and subsequently transported them to the containment laboratory in Fred-ericton.Trees that were caged throughout larval devel-opment were not caged from late October to15Decem-ber because parasitoids were not active during this period.However,substantial predation of T.fuscum lar-vae by woodpeckers occurred during this period. After transport to Fredericton,we placed each bolt in a Plexiglas cage and incubated bolts at20?C to facilitate T.fuscum adult emergence,which began3 wk after the start of the incubation period.Tetropium fuscum emergence ceased after11wk(except for one individual that emerged after15wk),but bolts were incubated for an additional5wk to ensure that all adults had emerged.After theTrst16wk of incubation, we peeled the bark from a subsample of two bolts per treatment,and found live T.fuscum larvae developing in bolts from both the healthy and girdled treatments. Tetropium fuscum and T.cinnamopterum larvae were distinguished based on the shape of their urogomphi (J.S.,unpublished data).Consequently,we placed the remaining18bolts per treatment in cold storage for16 wk(5?C for2wk followed by14wk at?2?C),to simulate a second winter,which may be required to satisfy diapause requirements of late instars that would have been early instars during the winter of2008D2009.After16wk of cold temperatures,bolts were incubated at20?C for an additional16wk.Throughout both incubation periods,we monitored insect emer-gence6d per week and collected any T.fuscum that emerged.Each emerged beetle was sexed and the length of adult elytra,a proxy for adult size,was mea-sured using an ocular micrometer on a dissecting scope at10?magniTcation.We also recorded devel-opment time(number of days incubated in the labo-ratory at20?C)for each adult that emerged.Voucher specimens are stored at the Atlantic Forestry Centre, Fredericton,NB.
We collected emerged parasitoids of T.fuscum throughout both incubation periods.In Canada,T.fus-cum is host to at least two native parasitoids,Wroughtonia occidentalis(Cresson)(Hymenoptera:Braconidae)and Rhimphoctona macrocephala(Provancher)(Hymenop-tera:Ichneumonidae)(Sweeney et al.2005).These are solitary koinobiont endoparasitoids of Tetropium spp. (Yu et al.2005).As larvae of T.cinnamopterum(Kirby), a native congener,were present in several study trees (see results),we do not know whether parasitoids emerged from T.fuscum or T.cinnamopterum and,there-fore,report percentage parasitism of Tetropium spp. After incubation was complete,we counted the number of woodpecker holes on each bolt to esti-mate predation of larvae by woodpeckers.Subse-quently,we peeled the bark and estimated larval density of Tetropium spp.at the time that predation occurred by counting the number of dead immature Tetropium https://www.doczj.com/doc/c114484221.html,rvae under the bark and the num-bers of pupal cells under the bark and in the sap-wood.This method may underestimate Tetropium https://www.doczj.com/doc/c114484221.html,rval density because woodpeckers also may have preyed on immature larvae.Therefore,we included the number of woodpecker holes per bolt in a second estimate of larval density,although this may overestimate density because each wood-pecker hole may not have resulted in the death of a Tetropium https://www.doczj.com/doc/c114484221.html,rva.
We visually estimated the percentage of phloem (surface area)consumed by all phloem feeders on six10-cm2sections on each bolt by using a2-cm grid. Sampling started with a randomly chosen point along the bottom of each bolt,followed by system-atic sampling of sections diagonal to the previously sampled area in a counter-clockwise fashion.This gave us two sections from each of the top,middle, and bottom sections of each bolt,which were av-eraged for each tree.We did not estimate the per-centage of phloem consumed for the six bolts(two per tree condition)that were peeled after theTrst incubation period.
Effect of Tree Condition on Oviposition.To test the assumption that a similar number of eggs were laid on trees from the three tree condition treatments, we conducted an independent study in2009.In early May,30apparently healthy red spruce trees (20-to24-cm DBH)with full green crowns were selected in a mature,mixed-wood,red spruce-dom-inated stand near Lower Sackville,Nova Scotia(44?51.892?N,063?39.462?W).This stand is also within the area currently infested by T.fuscum.On22May 2009,we fastened two drawstring cages around the bole of each tree at50D80and90D120cm above the tree base.We randomly assigned each tree to one of three host conditions:healthy,girdled,or cut(10 trees per tree condition)and treated trees on25 June2009,as described in Description of Site and Tree Manipulation.
On28July(24trees,eight per tree condition)or5 August(six trees,two per tree condition),we placed into each cage one male and one female T.fuscum that had been observed mating.Nine days after adults were placed in cages,we cut two30-cm-long bolts from the caged portions of each tree and immediately trans-ported bolts to the Atlantic Forestry Centre,where they were stored at?2?C.For each tree,we randomly selected one bolt and removed all of the bark and phloem in?70-cm2pieces.We dissected bark pieces under a dissecting microscope and counted the num-ber of eggs laid by T.fuscum females.Because of a longer than expected time required to process each bolt,we processed only one bolt per tree. Statistical Analysis.Standard errors accompany all means in the text or inTgures,and we present least square means for all percentage data.The date that T. fuscum were caged on trees was not a signiTcant factor
1202E NVIRONMENTAL E NTOMOLOGY Vol.40,no.5
in any preliminary analyses,so we pooled data across dates for subsequent analyses.When assumptions of parametric tests were not satisTed,as indicated by residual plots and Levene?s test,we analyzed data using either generalized linear modeling (GLM)or transformed data by log 10,log 10(x ?1),or arcsine square-root,before analysis of variance (ANOVA)(Zar 1999).We selected probability distributions for GLM by minimizing measures of goodness-of-Tt,in-cluding deviance,Pearson ?2,and log-likelihood.Gen-eralized linear models used logit links and binomial probability distributions unless otherwise speciTed.We conducted all analyses by using PASW Statistics 18,version 18.0.0(SPSS 2009,Chicago,IL).
Oviposition.We used a three-way ANOVA to eval-uate the effects of tree condition,position (50D80or 90D120cm from the tree base),and date on the num-ber of eggs laid per bolt in the 2009experiment.Colonization and Apparent Survival.We used a GLM to evaluate the effects of tree condition and caging on the number of trees from which at least one T.fuscum completed development.We used a two-way ANOVA to evaluate the effects of tree condition and caging on the mean number of T.fuscum adults that emerged per bolt.
Competition,Parasitism,and Predation.We used GLM to evaluate the effects of tree condition and caging on the number of T.cinnamopterum that emerged per bolt (logarithmic link and negative bi-nomial distribution)and the percentage of emerged Tetropium sp.that were T.cinnamopterum.We used a two-way ANOVA to evaluate the effects of tree con-dition and caging on the percentage of phloem con-sumed per bolt.To evaluate the effect of tree condi-tion on the percentage of Tetropium spp.that was parasitized by R.macrocephala,W.occidentalis,or either parasitoid in exposed trees,we used GLM.We did not observe any evidence of predation by woodpeckers from June to October 2008.The preda-tion by woodpeckers we report here occurred from late October to December 2008while the bolts were stored at the stand boundary.As we removed cages from trees just before they were cut in October,we did not include a caging factor in analyses of predation by woodpeckers.Although we had already cut trees in the healthy and girdled treatments before predation by woodpeckers,variation in the condition of the bolt because of tree treatments may have in?uenced pre-dation,and therefore,we included tree condition treatment as a factor in this analysis.We used GLM with logarithmic links and negative binomial distribu-tions to evaluate the effect of tree condition on the number of woodpecker holes per bolt and the effect of Tetropium https://www.doczj.com/doc/c114484221.html,rval density on the number of woodpecker holes per bolt.We also used a linear regression,Ttting a sigmoid curve,to evaluate the relationship between larval density and the number of woodpecker holes per bolt.These analyses were con-ducted with and without the number of woodpecker holes included in the estimate of larval density,as described above.
Size,Sex Ratio,and Development Time.We used GLM to evaluate the effects of tree condition and caging on the sex ratio of emerged T.fuscum adults.Tetropium fuscum adults emerged in two distinct co-horts (see results).Therefore,GLM was also used to evaluate the effects of treatment and caging on the percentage of T.fuscum that emerged in each cohort.We used a MANOVA to evaluate the effects of tree condition,caging,and sex on the mean elytra length and development time of emerged adult T.fuscum.Tree condition (Pillai?s Trace ?0.75;F 4,106?15.73;P ?0.001)and sex (Pillai?s Trace ?0.28;F 2,52?10.07;P ?0.001),but not caging (Pillai?s Trace ?0.05;F 2,52?1.29;P ?0.29)or any interaction,were signiTcant in the MANOVA and were,therefore,included as factors in separate two-way ANOVAs evaluating elytra length and development time independently.We added a cohort factor to subsequent ANOVAs,along with any factors that were signiTcant in the original ANOVA models.We included only trees where two or more T.fuscum emerged in these analyses.To graphically represent emergence phenology with respect to tree condition,we categorized daily adult T.fuscum emergence into 3-d intervals.
Results
Oviposition.Neither tree condition (F 2,19?0.59;P ?0.57),position (F 1,19?1.44;P ?0.25),date (F 1,19?0.092;P ?0.77),nor any two-or three-way interactions (P ?0.75)in?uenced the number of eggs laid on each bolt.This supports our assumption that a similar number of eggs were laid on trees in each tree condition treatment in the 2008experiment.
Colonization and Apparent Survival.Tree condi-tion,but not caging,in?uenced the number of trees on which at least one T.fuscum completed development (Table 1).Tetropium fuscum emerged from 17of 20healthy and girdled trees,and from only nine of 20cut trees.
Tree condition,caging,and their interaction in?u-enced the number of T.fuscum adults that emerged per bolt (Table 2).When trees were caged,emer-gence was much higher on bolts cut from girdled than from healthy or cut trees (Fig.1).In contrast,when trees were exposed,emergence was highest on healthy trees (Fig.1).As we assume that an equal number of eggs were laid on trees in each treatment,the number of T.fuscum adults that emerged estimates apparent survival from egg to adult.
Competition,Parasitism,and Predation.Two,seven,and 10species of bark and wood-boring insects (i.e.,potential competitors)emerged from healthy,girdled,and cut trees,respectively (Table 3).Te-tropium cinnamopterum emerged from only one of 20healthy trees,but from six of 20cut and 11of 20girdled trees.The number of T.cinnamopterum that emerged was in?uenced by tree condition,caging,and their interaction (Table 1).On both caged and exposed trees,T.cinnamopterum emergence was highest when the tree was girdled (Fig.2).The number of T.cin-namopterum that emerged from cut or healthy trees
October 2011F LAHERTY ET AL .:E FFECT OF H OST C ONDITION ON T .fuscum P ERFORMANCE 1203
was higher when trees were caged than when they were exposed,but a similar number emerged from exposed and caged girdled trees(Fig.2).Tetropium cinnamopterum likely colonized caged trees before the manipulation of T.fuscum,which coincided with cage placement on trees,but occurred several weeks after tree condition treatments.
Only the interaction between tree condition and caging had a signiTcant effect on the percentage of emerged Tetropium spp.that was T.cinnamopterum (Table1).On exposed girdled trees(60?5%),more T.cinnamopterum emerged than in all other groups (caged girdled18?2%,caged cut23?5%,and exposed cut11?10%).Tree condition,but not caging, in?uenced the percentage phloem consumed per tree (Table2).Phloem consumption was more than four times higher on cut and girdled trees than on healthy trees(Fig.3a).
Tetropium spp.developing on caged trees were oc-casionally parasitized,but parasitism rates were low
Table1.Summary of generalized linear models evaluating effects of tree condition and caging on several quanti?ed dependent
variables
Dependent variable Source of variation df Wald?2P
Number of trees on which at least one T.fuscum completed development Tree condition2 6.590.04
Caging10.380.44
Tree condition?caging2 1.620.45 Number of T.cinnamopterum that emerged per bolt Tree condition224.14?0.01
Caging17.07?0.01
Tree condition?caging1 3.94?0.05 Percentage of emerged Tetropium spp.that were T.cinnamopterum Tree condition2 4.770.09
Caging10.870.35
Tree condition?caging1 6.290.01 Percentage parasitized by W.occidentalis Tree condition115.91?0.01 Percentage parasitized by R.macrocephala Tree condition227.59?0.01 Percentage parasitized by either parasitoid Tree condition234.04?0.01 Number of woodpecker holes per bolt Tree condition240.07?0.01 T.fuscum adult sex ratio Tree condition20.430.81
Caging10.180.67
Tree condition?caging2 1.940.38 Percentage of T.fuscum that emerged in the second cohort Tree condition197.94?0.01
Caging1 2.000.16
Tree condition?caging1 1.780.18 Table2.Two-and three-way analyses of variance evaluating effects of tree condition,caging,and sex on several quanti?ed dependent
variables
Dependent variable Source of variation df MS F P Number of T.fuscum that emerged per bolt(log10(x?1))Tree condition2 1.9911.26?0.01
Caging1 1.8210.28?0.01
Tree condition?caging2 2.2312.62?0.01
Error540.18
Percentage phloem consumed(arcsine square-root)Tree condition2 2.16328.74?0.01
Caging10.0070.090.77
Tree condition?caging20.0740.980.38
Error470.075
Adult elytra length(log)Tree condition20.06233.67?0.01 Overall Sex10.03317.80?0.01
Tree condition?sex20.0020.910.41
Error580.002
Including cohort Tree condition20.0059 3.850.02
Sex10.038825.40?0.01
Cohort10.033121.68?0.01
Tree condition?sex20.00110.740.48
Tree condition?cohort10.00040.240.62
Sex?cohort10.00130.840.36
Tree condition?sex?cohort1--
Error650.0015
Development time(log)Tree condition2 1.69484.50?0.01 Overall Sex10.0010.070.79
Tree condition?sex20.0030.150.86
Error580.020
Including cohort Tree condition20.06513.56?0.01
Cohort1 1.516318.27?0.01
Tree condition?cohort10.018 3.700.06
Error650.005
Transformations of dependent variables are indicated in parentheses.SigniTcant factors in overall models evaluating elytra length and development time were re-analyzed with the added effect of cohort.
1204E NVIRONMENTAL E NTOMOLOGY Vol.40,no.5
(6.00?0.02%).Parasitoids emerging from caged trees likely parasitized naturally occurring Tetropium spp.before trees were caged,but it is possible that some oviposited through mesh cages.Tree condition in?u-enced the percentage of Tetropium spp.parasitized by R.macrocephala,W.occidentalis,or by either parasi-toid (total parasitism)on exposed trees (Table 1).Total parasitism was relatively high on cut and girdled trees,but signiTcantly reduced on healthy trees (Fig.3b).On cut trees,the percentage of larvae parasitized by W.occidentalis was double that parasitized by R.macrocephala,whereas W.occidentalis contributed lit-tle to the overall parasitism rate on girdled trees (Fig.3b).Only R.macrocephala parasitized Tetropium spp.developing in healthy trees (Fig.3b).
Tree condition in?uenced the number of woodpecker holes per bolt (Table 1).Bolts from girdled trees had twice as many woodpecker holes as cut trees and ten times more than healthy trees (Fig.3c).There was a positive relationship between the number of Tetropium https://www.doczj.com/doc/c114484221.html,rvae per bolt and the number of woodpecker holes per bolt,whether the estimate of larval density excluded (Wald ?2?45.39;P ?0.001)(Fig.4)or included (Wald
?2?72.57;P ?0.001)the number of woodpecker holes per bolt.
Size,Sex Ratio,and Development Time.Neither tree condition nor caging in?uenced T.fuscum adult sex ratio (Table 1),which was slightly male biased (1.2males per female).The elytra of adult T.fuscum females (7.6?0.2mm)were signiTcantly longer than those of males (6.7?0.1mm)(Table 2),and adults emerging from healthy trees (7.9?0.2mm)were signiTcantly larger than those emerging from cut (6.5?0.3mm)or girdled (6.7?0.1mm)trees (Table 2).
Tetropium fuscum emergence began 23d after the start of the Trst incubation period,and adults emerged continually until day 80(Fig.5).Only one adult emerged between days 80and 112(Fig.5).Between days 112and 113of incubation at 20?C,a second winter period was simulated (see methods).Eighteen days after the end of the simulated winter (day 130of incubation),T.fuscum emergence recommenced and continued until day 213(Fig.5).When the bark was removed from bolts at the end of the second incuba-tion period,19live T.fuscum larvae in total were found developing in bolts from three healthy trees (16,2,and one larvae per bolt).
Tree condition also in?uenced T.fuscum develop-ment time (Table 2).Adults that developed in cut trees emerged earliest (39?2d),followed by those from girdled trees (51?4d)(Fig.5).Tetropium fuscum developing in healthy trees took much longer to emerge (140?8d)(Fig.5).There was no signif-icant difference in the development time of male and female T.fuscum (Table 2).
Tetropium fuscum adults emerged in two distinct cohorts (Fig.5),perhaps representing 1-and 2-yr development times.There was a signiTcant effect of tree condition,but not caging,on the percentage of T.fuscum that emerged in the Trst versus the second cohort (Table 1).All adult T.fuscum that developed in cut trees,and most of those that developed on girdled trees (95?2%),emerged in the Trst cohort (Fig.5).In contrast,few T.fuscum that developed on healthy trees (29?4%)emerged in the Trst cohort (Fig.
5).
Fig.2.Mean (?SE)number of T .cinnamopterum adults that emerged from bolts cut from healthy,girdled,or cut red spruce trees.Bolts were either caged or exposed from June to October
2008.
Fig.1.Mean (?SE)number of T .fuscum adults that emerged from bolts cut from healthy,girdled,or cut red spruce trees,where developing T .fuscum were either caged or exposed during larval development (June to October 2008).
Table 3.List of bark-and wood-boring insects that emerged from bolts cut from healthy,girdled,or cut red spruce trees near En?eld,Nova Scotia,Canada
Species
Cut
Girdled
Healthy
Hymenoptera:Siricidae
Urocerus albicornis (Fabricius)a a Coleoptera:Cerambycida e
Tetropium cinnamopterum (Kirby)a a a Coleoptera:Curculionidae:Scolytinae Polygraphus ru?pennis (Kirby)a a a
Dendroctonus ru?pennis (Kirby)a a Dryocoetes affaber (Mannerheim)a a Dryocoetes autographus (Ratz.)a a Crypturgus borealis Swaine a a
Crypturgus pusillus (Gyllenhal)a Gnathotrichus materiarius (Fitch)a Trypodendron sp.
a
a
Indicates that a species emerged from a given treatment.Voucher specimens can be found at the Atlantic Forestry Centre,Fredericton,New Brunswick,Canada.
October 2011F LAHERTY ET AL .:E FFECT OF H OST C ONDITION ON T .fuscum P ERFORMANCE 1205
There was a signiTcant effect of emergence co-hort on mean elytra length and,predictably,on mean development time (Table 2).All factors sig-niTcant in the original models also were signiTcant in the reduced models,with the added effect of cohort,and exhibited the same trends (Table 2).Adults emerging in the second cohort were larger (8.3?0.2versus 6.6?0.1mm)and took longer to develop (166?3versus 46?2d)than those that emerged in the Trst cohort.Interactions between cohort and tree condition were not signiTcant in either model (Table 2),indicating that within each
cohort,T.fuscum were larger and took longer to develop on healthy trees.
Discussion
In contrast to reports from its native range,where it attacks stressed,moribund,or recently felled Nor-way spruce (Schimitschek 1929,Juutinen 1955),T.fuscum successfully developed when adults were forced to oviposit on apparently healthy red spruce in Nova Scotia.As predicted,the performance of T.fus-cum was in?uenced by the physiological condition of host trees both directly,presumably through varia-tions in nutritional quality and host resistance,and indirectly,through its in?uence on natural enemies and competitors.
Apparent survival of T.fuscum was higher on healthy than on experimentally stressed (cut and gir-dled)trees when developing larvae were exposed to natural enemies and competitors from June to Octo-ber.The beneTts of reduced competition and para-sitism on healthy,compared with stressed trees,ap-peared to compensate for any reductions in nutritional quality and/or increased host resistance.
When developing T.fuscum larvae were protected from natural enemies (but unfortunately not compet-itors)by caging,survival was higher on slow-growing,moisture-stressed,girdled trees than on apparently healthy or cut trees.Moisture or drought stress can reduce oleoresin exudation pressure (Mattson and Haack 1987b)and the production of induced oleo-resin in conifers (Croise ′and Lieutier 1993,Cobb et al.1997,Lombardero et al.2000)and also may cause qualitative changes in oleoresin composition (Hodges and Lorio 1975).Oleoresin is an important mechanism of resistance for conifers (Phillips and Croteau 1999),and reductions in its quantity or quality can increase the performance of phloeophagous insects and asso-ciated fungi (Berryman 1972,Mattson and Haack 1987b,Paine et al.1997,Shibata 2000,Tisdale et al.2003).This may explain the high rates of T.
fuscum
Fig.3.In?uence of tree condition on (a)the mean (?SE)percentage phloem consumed per bolt by all phloem feeders,(b)the mean (least square)percentage of Te-tropium spp.parasitized by W .occidentalis and R .macro-cephala on exposed (uncaged)bolts,and (c)the mean (?SE)number of woodpecker holes per bolt.Treatment means with different letters or numbers are signiTcantly different ([a]REGW multiple comparisons test,[b],and [c]pair-wise comparisons of least square means).In 3b,numbers,uppercase and lowercase letters indicate the signiTcance of pair-wise comparisons for total percentage parasitism,parasitism by R .macrocephala ,or parasitism by W .occidentalis ,
respectively.
Fig.4.Relationship between Tetropium https://www.doczj.com/doc/c114484221.html,rval den-sity and the number of woodpecker holes per https://www.doczj.com/doc/c114484221.html,rval density was estimated by counting the number of Tetropium spp.pupal cells and dead immature larvae when bark was peeled from bolts.
1206E NVIRONMENTAL E NTOMOLOGY Vol.40,no.5
apparent survival on caged,girdled trees in this study.Girdling may cause trees to be even less well defended than naturally drought-stressed trees as a result of severing carbohydrate transport to the roots and a reduction in the cross-sectional area of sapwood.In a similar study,fewer Semanotus japonicus Lacordaire (Coleoptera:Cerambycidae)larvae died as a result of resin produced in traumatic resin canals when they developed on experimentally stressed compared with untreated Japanese cedar (Cryptomeria japonica D.Don.)trees (Shibata 2000).
Higher survival,in the absence of natural enemies,on caged girdled than on caged healthy or cut trees may also have resulted from improved larval nutrition.Stressed trees often contain higher or more balanced levels of nutrients (Mattson and Haack 1987a),
including minerals,carbohydrates,and nitrogen (Hodges and Lorio 1969,White 1984,Mattson and Haack 1987b).
Although host resistance likely was negligible in cut trees,apparent survival was still low.Caging did not prevent colonization by competitors,and thus,low survival on caged cut trees may be because of high levels of interspeciTc competition,which may have reduced the amount of nutrition and space available for larval development.
The development of juvenile T.fuscum was pro-longed on healthy compared with cut and girdled trees.In Nova Scotia,most adults emerge in mid-June (Rhainds et al.2010),and adults that emerge later may experience reduced mate-Tnding success.When de-veloping on healthy trees,most T.fuscum adults emerged in the second cohort and would likely have taken 2yr to develop in the Teld.A second year of development inherently reduces Ttness by half and increases exposure time to natural enemies and to harsh winter weather.However,multiyear generation times appear to optimize Ttness for some cerambycids,especially when food quality and natural enemy pres-sure is low (Walczyn ′ska et al.2010),similar to healthy trees in this study.In an independent study,larvae
dissected from healthy trees were smaller (earlier instar)than larvae dissected from girdled trees after one summer of development in the Teld (L.F.,un-published data).The mechanism delaying larval de-velopment in healthy trees is unknown,and is likely related to reductions in larval nutrition (Mattson and Haack 1987a).
Contrary to our predictions,adult T.fuscum that emerged from healthy trees were larger than those that emerged from cut or girdled trees.This increase in size does not necessarily indicate that healthy trees are more nutritious than girdled or cut trees,as it may result from feeding for a longer period of time or because systemic tree defenses were weakened (or eliminated)once bolts were cut from living healthy trees.In the current study,all trees were cut in fall,and any larvae that had not matured continued to develop in cut bolts (see methods).Subsequent studies should evaluate the effect of host condition on T.fuscum adult size (and other measures of performance)when ju-veniles complete their entire development on living trees in the Teld.
In Europe,woodpeckers cause signiTcant (?20%)mortality of Tetropium https://www.doczj.com/doc/c114484221.html,rvae,and are regarded as their most important predator (Schimitschek 1929,Juutinen 1955,Kenis and Hilszczanski 2004).The high number of woodpecker holes (especially in the gir-dled treatment)observed on bolts in this study sug-gests that woodpeckers are also an important predator of Tetropium spp.in Nova Scotia.There was an effect of tree condition on the number of woodpecker holes per bolt (i.e.,more woodpecker holes were found on girdled than on healthy or cut trees),but this may be attributed to variations in the density of Tetropium spp.or other bark or wood borers,similar to emerald ash borer predation by woodpeckers (Lindell et al.2008).High rates of parasitism partially explain why T.fuscum apparent survival was higher on caged than on exposed cut and girdled trees.However,when
caged,
Fig.5.Emergence phenology for T .fuscum developing in red spruce trees that had been cut,girdled or were healthy (not manipulated)before being exposed to ovipositing T .fuscum .Bolts were collected from the Teld on 15December 2008and subsequently incubated at 20?C for 112d,followed by 112d of simulated winter and another 112d incubation at 20?C.The number of T .fuscum that emerged is categorized into 3-d intervals.
October 2011F LAHERTY ET AL .:E FFECT OF H OST C ONDITION ON T .fuscum P ERFORMANCE 1207
survival was much lower on cut than on girdled trees, indicating that parasitism alone cannot explain low rates of apparent survival on exposed cut https://www.doczj.com/doc/c114484221.html,rvae may have had less phloem and space available for successful development in cut than in girdled trees. Larval eclosion occurred between3and7wk after the treatment of cut trees,during which time cut trees were rapidly colonized by competitors,especially sco-lytids and associated fungi.The number of bark and wood-boring species that colonized cut trees and the percentage of phloem consumed by all phloem-feed-ers were highest on cut trees,despite the fact that few T.fuscum emerged.Thus,the reduced apparent sur-vival on exposed,as opposed to caged,girdled trees is probably due,at least in part,to interspeciTc compe-tition,as the percentage of Tetropium spp.that were T.cinnamopterum was low for all groups except for exposed girdled trees.
Parasitoids also cause signiTcant mortality of T.fus-cum in its native range(Schimitschek1929,Juutinen 1955,Kenis and Hilszczanski2004),and rates of par-asitism were similarly high in Nova Scotia.As pre-dicted,parasitoids foraged more often or more efT-ciently on cut and girdled than on apparently healthy trees.Parasitism of another longhorn beetle,S.japoni-cus,was also lower in untreated than in mechanically stressed trees(Shibata2000).An increase in parasit-ism on stressed trees may result from primary attrac-tion of parasitoids to stressed tree volatiles(Sullivan et al.1997,Pettersson2001,Rojas et al.2006),as foraging on stressed trees may increase their likelihood ofTnd-ing host insects that colonize these trees. Alternatively,larvae developing on healthy trees may be less susceptible to postalighted parasitoids because of phenological asynchrony between ovipos-iting parasitoids and susceptible host insects caused by changes in host development rates.This likely did not reduce parasitism of T.fuscum by W.occidentalis on healthy trees in our study,as this species parasitizes early instar T.fuscum(L.F.,unpublished data).As larval development was delayed on healthy trees,lar-vae developing therein should have been more sus-ceptible to this parasitoid.The life stage(s)parasitized by R.macrocephala are unknown.If they parasitize later instars,T.fuscum developing on healthy trees may initially be less susceptible to this parasitoid(i.e., in theTrst summer).However,R.macrocephala adults emerge at about the same time as W.occidentalis, shortly after T.fuscum adults(L.F.,unpublished data) and,therefore,likely also parasitize early instars. This research evaluates complex novel ecological interactions among an exotic herbivore,its host tree, competitors,and natural enemies.Tree condition ap-pears to have a large direct impact on T.fuscum per-formance,in?uencing apparent survival,development time,and adult size.It also appears to mediate the impact of natural enemies and competitors,further in?uencing T.fuscum performance.Understanding how the performance of this exotic herbivore is in-?uenced by factors from multiple trophic levels is essential to understanding its population dynamics (Price et al.1980,Moreau et al.2006)and the risk it poses to North American forests.Further research should examine the oviposition preference of T.fus-cum to evaluate more comprehensively the risk asso-ciated with this exotic beetle.
Acknowledgments
We thank R.Johns,S.Heard,C.Simpson,and three anon-ymous reviewers for comments on an earlier version of this manuscript,K.van Rooyen, A.Morrison,K.Pronk, C. Hughes,G.Fraser,D.MacFarlane,https://www.doczj.com/doc/c114484221.html,eau,T.McCarthy, H.Williams,A.Doane,T.Harrison,W.MacKay,J.Price,S. Palmer,W.McKinnon,and S.Carmichael for technical as-sistance,and J.Major and G.Goodine for the use of their pressure bomb.This research was supported by the Canadian Forest Service and the Natural Science and Engineering Research Council of Canada,and through SERG Interna-tional by Forest Protection Limited,Ontario Ministry of Natural Resources,Nova Scotia Department of Natural Re-sources,and Newfoundland Department of Natural Re-sources.
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Received30April2011;accepted27July2011.
October2011F LAHERTY ET AL.:E FFECT OF H OST C ONDITION ON T.fuscum P ERFORMANCE1209
服务器的三大虚拟系统对比分析 服务器对于网站来说是举足轻重的，选择一个好的服务器就直接关系到了网站的发展，服务器的重要性是不言而喻的，那么对于服务器的三大虚拟系统站长们是否了解呢？专职优化、域名注册、网站空间、虚拟主机、服务器托管、vps 主机、服务器租用的中国信息港来为你探究！ 近几个月中虚拟化领域发生了不少事情，年中CITrix将Xen Server免费并推出了新的 5.5 版;10 月微软推出了WindowsServer 2008 R2,集成Hyper-v 2.0，具有不少新的特性，增加了对RadHat Linux的支持;VMware则推出了VSphere 4，来管理和整合其产品线，并且可以支持更多的虚拟机。 在下文中我们将对这几个新的虚拟化产品进行比较，但比较之前需要关注一些问题： 1、预装的虚拟化系统的服务器越来越多 大多数OEh希望将虚拟化系统捆绑到服务器上，这样可以额外的收取服务费用和售前支持费用。在2010年可能将有一些厂商推出专门的虚拟化服务器，就像 今年Cisco发布的统一通信平台，而虚拟机的密度也将大幅提升一一服务器内存的容量也需要达到TB级来支持数以十计甚至数以百计的虚拟机实例。 微软的Hyper-V Server 2008 R2 可以支持新的CPL特性，女口AMD勺RVI 快速虚拟化索引(Rapid Virtualization Indexing) 和Intel的扩展页表 (Exte nded Page Table)技术，可以提高虚拟机的性能。 2、预装的虚拟化软件微软和CITrix并不占优势 VMware仍然是预装最多的虚拟化系统，尽管Xen在网站上展示着它配置起来有多简单。CITrix将更多的精力放在Project Kensho计划上，在这个计划中，Citrix 用户可以用开放的虚拟机格式输入和输出虚拟机，可以和微软虚拟化共享。Citrix 还具有一连串名为“Citrix 云中心”的亚马逊弹性云资源，将其多 种网络和虚拟化工具放到云上，为潜在用户提供实验平台。 而VMware可以通过vAPP支持开放虚拟化格式OVF在切换虚拟化系统或管 理混合环境时具有更好的交互性。 3、虚拟化许可证仍然混乱 VMware并没有把许可证问题简单化，其低价产品vSphere esse ntials 售价为995美金，支持3台物理服务器，每台服务器支持两个CPU Windows还是具有多种Guest许可证，让应用更复杂。而现在Xen Server和Hyper-v都已经免费，如果许可证具有单一的价格，这些虚拟化系统应用起来会更方便。
“的、地、得”用法分析及练习（后附答案） 一、的、地、得用法分析： “的”后面跟的都是表示事物名称的词或词语，如：敬爱的总理、慈祥的老人、戴帽子的男孩、珍贵的教科书、鸟的天堂、伟大的祖国、有趣的情节、优雅的环境、可疑的情况、团结友爱的集体、他的妈妈、可爱的花儿、谁的橡皮、清清的河水...... “地”后面跟的都是表示动作的词或词语，如：高声地喊、愉快地唱、拼命地逃、疯狂地咒骂、严密地注视、一次又一次地握手、迅速地包围、沙沙地直响、斩钉截铁地说、从容不迫地申述、用力地踢、仔细地看、开心地笑笑......” “得”前面多数是表示动作的词或词语，少数是形容词；后面跟的都是形容事物状态的词或词语，表示怎么怎么样的，如：走得很快、踩得稀烂、疼得直叫唤、瘦得皮包骨头、红得发紫、气得双脚直跳、理解得十分深刻、乐得合不拢嘴、惊讶得目瞪口呆、大得很、扫得真干净、笑得多甜啊...... 二、的、地、得用法补充说明： 1、如果“de”的后面是“很、真、太”等这些词，十有八九用“得”。 2、有一种情况，如“他高兴得一蹦三尺高”这句话里，后面的“一蹦三尺高”虽然是表示动作的，但是它是来形容“高兴”的程度的，所以也应该用“得”。
三、的、地、得用法总结： 1、“的”前面的词语一般用来修饰、限制“的”后面的事物，说明“的”后面的事物怎么样。结构形式一般为：修饰、限制的词语+的+名词。 2、“地”前面的词语一般用来形容“地”后面的动作，说明“地”后面的动作怎么样。结构方式一般为：修饰、限制的词语+地+动词。 3、“得”后面的词语一般用来补充说明“得”前面的动作怎么样，结构形式一般为：动词（形容词）+得+补充、说明的词语。 四、的、地、得用法例句： 1. 蔚蓝色的海洋，波涛汹涌，无边无际。 2. 向日葵在微风中向我们轻轻地点头微笑。 3. 小明在海安儿童公园玩得很开心。 五、“的、地、得”的读音： “的、地、得”是现代汉语中高频度使用的三个结构助词，都起着连接作用；它们在普通话中都各自有着各自的不同的读音，但当他们附着在词，短语，句子的前面或后面，表示结构关系或某些附加意义的时候都读轻声“de”，没有语音上的区别。 但在书面语中有必要写成三个不同的字，这样可以区分他们在书面语用法上的不同。这样做的好处，就是可使书面语言精确化。
云虚拟主机和云服务器有什么区别 云虚拟主机和云服务器有什么区别？云服务器是在一组集群服务器上虚拟出多个类似独立主机的部分，资源是完全独立的，不与其他空间共享。云虚拟主机是在原来虚拟主机的基础上，加入了云概念和云计算，是传统虚拟主机的发展和升级。因此它还是属于虚拟主机的一种。 云服务器有独立的IP、内存、硬盘、带宽等资源，可以根据需要安装各种操作系统以及配置各种网站运行环境，在功能以及稳定性方面都很强大。 采用云服务器，对于升级管理的成本也大大降低。云主机支持在线平滑升级和降级，无需搭建新的服务器环境，支持系统在线备份、还原，节省了运营成本和时间。云主机的管理简单，云服务商会提供基础的运维控制面板，简单易操作，且系统安装、重装均可一键调取镜像完成，极大减轻运维工作压力。 云虚拟主机是在服务器硬盘上虚拟出来的一部分容量，共享的是服务器资源，没有独立的IP和带宽，功能也比较有限，它所支持的程序也是在服务器上配置好的，用户无法自由配置环境以及安装软件。 云虚拟主机是从云服务器中又近一步划分，通过虚拟化管理软件，把云服务器分割成多个型号不等的小型空间，是中小型企业建站的理想选择！ 云虚拟主机作为云服务器划分出的一部分，容量和内存等比不上云服务器，但它在性能方面和价格方面都比传统虚拟主机好，具备高在线率、智能容错、正版系统、免备份等多项优势。 Cloudeasy云管家为企业提供云资源管理、数据库管理、中间件管理、云安全服务、监控告警、安装服务、故障处理、日志管理、运维报表、账单管理、费用分级管理、费用优化报表、上云咨询规划、迁移实施等丰富的云管理服务，满足企业全生命周期云管理服务需
门禁控制器接线 以下为485实用型门禁控制器接线图，TCP除通讯线为以太网连接外其他都一样485型门禁控制器接线图： TCP嵌入式门禁控制器接线图 建议安装调试过程
1．安装控制器主机，接通电源，短接一下出门按钮端子，观察继电器开锁指示灯状态变化。 2．接通485或TCP/IP通讯，安装软件，在软件里面添加控制器，注意填写正确的序列号或I P ，485的要选择正确的串口。 3．打开调试界面观察通讯情况。 4．观察是否正常通讯，通讯后用软件开关门，是否成功。 5．安装读卡器，刷卡操作是否有正确的记录。 6．增加用户、发卡、授权操作，下载卡到控制器，刷卡观察记录是否正常。 7．安装锁接上锁的连接线，再刷卡后观察记录和锁是否正常。 8．安装其它附属设备如按钮、门磁等。 9．复位清零操作：给控制器断电→短接复位跳线→通电5秒(听到控制器响两声)→断电→断开跳线→重新通电 门禁系统的施工布线规范和注意事项 读卡器到控制器：建议用8芯屏蔽多股双绞网线。红与红白接12V正，棕与棕白接12V负，绿接数据0，绿白接数据1，蓝接声光两条线(强烈建议接声光线)，不同的网线颜色, 不一定相同。线径建议0.5毫米以上。实际应用最长不可以超过60米，屏蔽线接控制器的GND；如通讯效果不佳，可增加读卡器的供电线线径。 按钮到控制器：采用两芯线，线径在0.3毫米以上。建议使用八芯网线，按钮接其中任意两根线即可，以后可以轻松改接读卡器，实现进出双向刷卡功能。 电锁到控制器：建议使用两芯电源线，线径在1.0毫米以上。如果超过50米要考虑用更粗的线，或者多股并联。最长不要超过100米，一般控制在70米以内。 门磁到控制器：建议选择两芯线，线径在0.3毫米以上，如果无需在线了解门的开关状态或者无需门长时间未关闭报警和非法闯入报警等功能，门磁线可不接。 控制器到控制器：以及控制器到转换器的线，建议使用线径在0.5毫米以上2芯屏蔽双绞线。485总线长度，理论上是可以达到1200米，建议根据控制器数量或者通讯环境的复杂性，不要超过800米。如果通讯质量不佳，请选用485集线器或者中继器来改善通讯环境。 485通讯布线说明：正接正，负接负，从最远的一个控制器到第二台、第三台……一直接到最近的一个控制器然后接到通讯转换器与电脑连接。
教你选择1G空间的双线虚拟主机 本文转自：新科互联 拥有网站的个人和企业越来越多，虽然现在云主机很火，但是还是有很多人会选择虚拟主机作为网站空间。在虚拟主机中，1G双线虚拟主机是一个比较常见的型号，容量大小和线路都比较适中。那么如何选择适合自己的1g双线虚拟主机呢？可以从以下几点考虑： 1g双线虚拟主机 一、实用 很多人购买1g双线虚拟主机最大的误区就是觉得空间越大越好,软文高手，其实这并不完全正确，要我说，适合自己的应用就够，否则多了资源也是浪费,同时也浪费了钱财。如果你只是用在普通网站上，那要求相对不是太高，在这里给大家推荐大家使用腾佑科技G 享云A.B型1g双线虚拟主机都在百来元内，相信都还能接受,而且可以先试用。 二、性价比 在保证1g双线虚拟主机的安全稳定的前提下成本优势就显得非常重要了。所以选择性价比高的1g双线虚拟主机可以自己节省一大笔不必要的开销，而且免费试用,产品丰富,预装网站功能, 这样功能强大的主机对于站长来说无疑是一个最好的选择。 三、实力 1g双线虚拟主机服务商实力代表着1g双线虚拟主机的质量和服务等各个方面的强弱。现在做1g双线虚拟主机的商家多而参差不
齐，选择时应先审核一下他们的资历，是不是权威认证的，有无正规的ICP经营许可证，这可是购买1g双线虚拟主机的第一关的参考。，腾佑科技作为一家拥有10年运营经验，且是河南第一家也是唯一一家IDC上市企业，我们很清楚客户对我们的信赖不仅是时间和荣誉的堆积，更是我们拥有自建的河南双线服务器托管机房，毕竟现在很少自建机房，自建机房是一种实力的象征。 四、所具备功能。 1g双线虚拟主机所具备的功能有几个方面，包括独立WEB空间大小，所支持的格式、还有企业邮局的大小和用户数的多寡，是否带有数据库开发能力：等，选择具备具备自己所需功能的主机。 五、服务水平。 服务水平，是选择中1g双线虚拟主机和重要的一点。因为没有一家IDC的1g双线虚拟主机产品不出现一点问题的，关键是出了问题服务能否跟得上，并能够立即去解决。一般那些有能力、实力强的1g双线虚拟主机企业会注重服务质量，腾佑科技提供一天24小时的全天服务。
门禁系统操作手册门禁控制器接线--原理图
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一．设备特性：1．485控制器特性第一部分门禁控制器硬件手册 门禁系统操作手册 485 门禁控制器使用标准的工业串口通信，通信距离可达1200 米，每个总线可以接255 台设备，使用 485 集线器可以扩展多条总线。支持多达6 个输出和10 个输入。型号有单门、双门、4门等。 ? 标准485（波特率9600）通讯； ? 大容量存储卡，54000 卡记录，60000 刷卡记录，10000 报警记录（控制器的记录保存在Flash 里 面； 双存储器，卡数据、刷卡记录分别存储，数据不易丢失；在脱机状况下，如果记录（刷卡记录和报 警记录）超出容量，将覆盖最早的记录）； ? 开门时区设置多达16 组，且可以分别设定对应的多种开门方式，如卡、卡+密码、密码、双卡、 首卡开门等； ? 支持远程操作开关门、远程开关火警、报警。支持软件锁门常闭功能； ? 支持多个报警事件的报警输出，如无效卡、无效时间、门报警、门开超时等； ? 默认支持2—4个weigend 读卡器，自动适应26、34、37协议； ? 支持多达6 个输出，分别控制门和报警输出联动； ? 多门控制器支持互锁、防潜返功能； ? 所有设备可以混合安装在一个系统里面； ? 配合软件支持考勤、实时在线巡更功能。支持多用户多机实时管理监控； ? 内置web 网页，同时可以网络实时监控； 2．T CP/IP控制器特性 以太网门禁控制器是专门为对通信要求比较高而设计的门禁设备。具有远程升级、远程初始化、数据 复位、防区功能的功能；可以扩展的485 接口空间；支持多达6个输出和10 个输入。是一个可以通过以太 网进行远程管理的门禁系统。型号有单门、双门、4门等。 ? 标准10M TCP/IP 通讯； ? 大容量存储卡，支持远程升级版卡容量4000，刷卡记录4000，报警记录6000； ? 标准版卡容量54000，刷卡记录60000，报警记录20000（控制器的记录保存在Flash 里面。在 脱 机状况下，如果记录（刷卡记录和报警记录）超出容量，将覆盖最早的记录）；双存储器，卡数据、 刷卡数据分别存储。
网络安全审计系统的实现方法 司法信息安全方向王立鹏1 传统安全审计系统的历史 传统的安全审计系统早在70年代末、80年代初就已经出现在某些UNDO系统当中，其审计的重点也是本主机的用户行为和系统调用。在随后的20年间，其他的各个操作系统也有了自己的安全审计工具，如符合C2安全级别的Windows NT, Nnux的syslog机制以及SUN 13SM等。 2 常用安全措施的不足和基于网络的安全审计系统的出现 近几年来，随着开放系统Internet的飞速发展和电子商务的口益普及，网络安全和信息安全问题日益突出，各类黑客攻击事件更是层出不穷。而相应发展起来的安全防护措施也日益增多，特别是防火墙技术以及IDS(人侵检测技术)更是成为大家关注的焦点。但是这两者都有自己的局限性。 2.1防火墙技术的不足 防火墙技术是发展时间最长，也是当今防止网络人侵行为的最主要手段之一，主要有包过滤型防火墙和代理网关型防火墙两类。其主要思想是在内外部网络之间建立起一定的隔离，控制外部对受保护网络的访问，它通过控制穿越防火墙的数据流来屏蔽内部网络的敏感信息以及阻挡来自外部的威胁。虽然防火墙技术是当今公认发展最为成熟的一种技术，但是由于防火墙技术自身存在的一些缺陷，使其越来越难以完全满足当前网络安全防护的要求。 包过滤型防火墙如只实现了粗粒度的访问控制，一般只是基于IP地址和服务端口，对网络数据包中其他内容的检查极少，再加上其规则的配置和管理极其复杂，要求管理员对网络安全攻击有较深人的了解，因此在黑客猖撅的开放Internet系统中显得越来越难以使用。 而代理网关防火墙虽然可以将内部用户和外界隔离开来，从外部只能看到代理服务器而看不到内部任何资源，但它没有从根本上改变包过滤技术的缺陷，而且在对应用的支持和速度方面也不能令人满意 2.2入侵检测技术的不足 人侵检测技术是防火墙技术的合理补充，能够对各种黑客人侵行为进行识别，扩展了网络管理员的安全管理能力。一般来说，人侵检测系统(IDS)是防火墙之后的第二层网络安全防护机制。 目前较为成熟的IDS系统可分为基十主机的IDS和基于网络的IDS两种。 基于主机的IDS来源于系统的审计日志，它和传统基于主机的审计系统一样一般只能检测发生在本主机上面的人侵行为。 基于网络的IDS系统对网络中的数据包进行监测，对一些有人侵嫌疑的包作出报警。人侵检测的最大特色就是它的实时性…准实时性)，它能在出现攻击的时候发出警告，让管理人员在在第一时间了解到攻击行为的发生，并作出相应措施，以防止进一步的危害产生。实时性的要求使得人侵检测的速度性能至关重要，因此决定了其采用的数据分析算法不能过于复杂，也不可能采用长时间窗分析或把历史数据与实时数据结合起来进行分析，所以现在大
门禁系统维护方案门禁控制器接线原理图
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一．设备特性：1．485控制器特性第一部分门禁控制器硬件手册 门禁系统操作手册 485 门禁控制器使用标准的工业串口通信，通信距离可达1200 米，每个总线可以接255 台设备，使用 485 集线器可以扩展多条总线。支持多达6 个输出和10 个输入。型号有单门、双门、4门等。 ? 标准485（波特率9600）通讯； ? 大容量存储卡，54000 卡记录，60000 刷卡记录，10000 报警记录（控制器的记录保存在Flash 里 面； 双存储器，卡数据、刷卡记录分别存储，数据不易丢失；在脱机状况下，如果记录（刷卡记录和报 警记录）超出容量，将覆盖最早的记录）； ? 开门时区设置多达16 组，且可以分别设定对应的多种开门方式，如卡、卡+密码、密码、双卡、 首卡开门等； ? 支持远程操作开关门、远程开关火警、报警。支持软件锁门常闭功能； ? 支持多个报警事件的报警输出，如无效卡、无效时间、门报警、门开超时等； ? 默认支持2—4个weigend 读卡器，自动适应26、34、37协议； ? 支持多达6 个输出，分别控制门和报警输出联动； ? 多门控制器支持互锁、防潜返功能； ? 所有设备可以混合安装在一个系统里面； ? 配合软件支持考勤、实时在线巡更功能。支持多用户多机实时管理监控； ? 内置web 网页，同时可以网络实时监控； 2．T CP/IP控制器特性 以太网门禁控制器是专门为对通信要求比较高而设计的门禁设备。具有远程升级、远程初始化、数据 复位、防区功能的功能；可以扩展的485 接口空间；支持多达6个输出和10 个输入。是一个可以通过以太 网进行远程管理的门禁系统。型号有单门、双门、4门等。 ? 标准10M TCP/IP 通讯； ? 大容量存储卡，支持远程升级版卡容量4000，刷卡记录4000，报警记录6000； ? 标准版卡容量54000，刷卡记录60000，报警记录20000（控制器的记录保存在Flash 里面。在 脱 机状况下，如果记录（刷卡记录和报警记录）超出容量，将覆盖最早的记录）；双存储器，卡数据、
北京电信通所研发的彩云主机采用领先的云计算技术，具有超高性价比；彩云主机可以解决用户担心数据丢失的后顾之忧；彩云主机可以不停机在线升级配置，保证用户业务的连续性；彩云主机还可以保证几乎不会发生硬件故障，保证系统稳定运行。 北京电信通所搭建的彩云主机与VPS（虚拟主机）的区别对比，如下： 1、技术： 彩云主机：采用领先的云计算技术，整合了计算、网络、存储等各种软件和硬件技术，走在国内前沿。 VPS：则是单纯虚拟化软件技术，达不到云计算技术的高标准。 2、安全性 彩云主机：拥有天然防ARP攻击和MAC欺骗设置，能够自主备份，数据永不丢失。 VPS：则是一个用户产生病毒或ARP攻击等问题，不仅影响自己，同服务器上的其他用户也受影响，风险大大增加。 3、可靠性 彩云主机：基于服务器集群，硬件全冗余，硬件损坏对用户几乎无影响，故障效率低。 VPS：单台服务器上承载若干用户，硬件损坏，则所有用户都面临业务中断的问题。 4、灵活性 彩云主机：用户可在线增加配置，实时增加，配置可扩展的空间。 VPS：不灵活，且增加配置受系统和物理服务器配置的局限。 5、性能 彩云主机：同等配置是独立服务器计算能力的4倍，可满足各种高性能计算要求。VPS：计算能力只限于一台服务器，存在计算资源瓶颈。若干用户分享一台服务器的计算能力。 6、隔离性 彩云主机：硬件隔离，完全达到物理独立的效果，且稳定性、数据备份等非常有保障。 VPS：物理独立，但一台服务器会面临稳定性、数据备份等诸多问题。 7、权限 彩云主机：Administrator/Root 权限（服务器管理员权限）。用户使用的是一台服务器的资源，可自主对服务器进行个性化设置。 VPS：仅FTP权限。若干用户共享一台服务器的资源，用户只能上传网页文件。 8、适用范围
标点符号用法 一、标点符号 标点符号：辅助文字记录语言的符号，是书面语的有机组成部分，用来表示语句的停顿、语气以及标示某些成分（主要是词语）的特定性质和作用。 句子：前后都有较大停顿、带有一定的语气和语调、表达相对完整意义的语言单位。 复句：由两个或多个在意义上有密切关系的分句组成的语言单位，包括简单复句（内部只有一层语义关系）和多重复句（内部包含多层语义关系）。 分句：复句内两个或多个前后有停顿、表达相对完整意义、不带有句末语气和语调、有的前面可添加关联词语的语言单位。 陈述句：用来说明事实的句子。 祈使句：用来要求听话人做某件事情的句子。 疑问句：用来提出问题的句子。 感叹句：用来抒发某种强烈感情的句子。 词语：词和短语（词组）。词，即最小的能独立运用的语言单位。短语，即由两个或两个以上的词按一定的语法规则组成的表达一定意义的语言单位，也叫词组。 二、分类 标点符号分为点号和标号两大类。
点号的作用是点断，主要表示说话时的停顿和语气。点号又分为句末点号和句内点号。 句末点号用在句末，表示句末停顿和句子的语气，包括句号、问号、叹号。 句内点号用在句内，表示句内各种不同性质的停顿，有逗号、顿号、分号、冒号。 标号的作用是标明，主要标示某些成分（主要是词语）的特定性质和作用。包括引号、括号、破折号、省略号、着重号、连接号、间隔号、书名号、专名号、分隔号。 （一）句号 1.用于句子末尾，表示陈述语气。使用句号主要根据语段前后有较大停顿、带有陈述语气和语调，并不取决于句子的长短。 2.有时也可表示较缓和的祈使语气和感叹语气。 请您稍等一下。 我不由地感到，这些普通劳动者也是同样值得尊敬的。 （二）问号 主要表示句子的疑问语气。形式是“？”。 1.用于句子末尾，表示疑问语气（包括反问、设问等疑问类型）。使用问号主要根据语段前后有较大停顿、带有疑问语气和语调，并不取决于句子的长短。 2.选择问句中，通常只在最后一个选项的末尾用问号，各个选项之间一般用逗号隔开。当选项较短且选项之间几乎没有停顿时，选项之间可不用逗号。当选项较多或较长，或有意突出每个选项的独立性时，也可每个选项之后都用问号。 3.问号也有标号的用法，即用于句内，表示存疑或不详。 马致远（1250？―1321）。 使用问号应以句子表示疑问语气为依据，而并不根据句子中包含有疑问词。当含有疑问词的语段充当某种句子成分，而句子并不表示疑问语气时，句末不用问号。
门禁系统操作手册门禁控制器接线原理图
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一．设备特性：1．485控制器特性第一部分门禁控制器硬件手册 门禁系统操作手册 485 门禁控制器使用标准的工业串口通信，通信距离可达1200 米，每个总线可以接255 台设备，使用485 集线器可以扩展多条总线。支持多达6 个输出和10 个输入。型号有单门、双门、4门等。 标准485（波特率9600）通讯； 大容量存储卡，54000 卡记录，60000 刷卡记录，10000 报警记录（控制器的记录保存在Flash 里面； 双存储器，卡数据、刷卡记录分别存储，数据不易丢失；在脱机状况下，如果记录（刷卡记录和报 警记录）超出容量，将覆盖最早的记录）； 开门时区设置多达16 组，且可以分别设定对应的多种开门方式，如卡、卡+密码、密码、双卡、首卡开门等； 支持远程操作开关门、远程开关火警、报警。支持软件锁门常闭功能； 支持多个报警事件的报警输出，如无效卡、无效时间、门报警、门开超时等； 默认支持2—4个weigend 读卡器，自动适应26、34、37协议； 支持多达6 个输出，分别控制门和报警输出联动； 多门控制器支持互锁、防潜返功能； 所有设备可以混合安装在一个系统里面； 配合软件支持考勤、实时在线巡更功能。支持多用户多机实时管理监控； 内置web 网页，同时可以网络实时监控； 2．T CP/IP控制器特性 以太网门禁控制器是专门为对通信要求比较高而设计的门禁设备。具有远程升级、远程初始化、数据 复位、防区功能的功能；可以扩展的485 接口空间；支持多达6个输出和10 个输入。是一个可以通过以太 网进行远程管理的门禁系统。型号有单门、双门、4门等。 标准10M TCP/IP 通讯； 大容量存储卡，支持远程升级版卡容量4000，刷卡记录4000，报警记录6000； 标准版卡容量54000，刷卡记录60000，报警记录20000（控制器的记录保存在Flash 里面。在脱
阿里云云主机搭建网站攻略 前言：虽然我也不知道前言有什么用，但是还是跟随潮流写了。我也不知道这应不应该叫攻略，因为我自己也是一个新手，只是想写些自己用了云主机的一些经验和心得。作为一个萌新其实也很慌的好吗！虽然不知道有几个人会看，其实网上也有很多关于云主机如何搭建的，我会写还是要感谢同样在玩云主机的三位朋友！作为一个新人第一次写这么正经的文章有点小小的羞耻，不知道会写多少，坚持多久，只是想试试，能够坚持多久！这篇攻略主要针对阿里云出售的云主机，windows的系统和Linux系统大致一样。 1.阿里云云主机 1.1用途 云主机大多用于搭建一些小型网站，由于操作简单，价格比云服务器要便宜，是新手的话推荐这个 1.2购买 如果是新手的话我推荐阿里云中售价分别为6元/每年和9.9元每年的共享虚拟主机惠普版（如果有朋友找不到的话，我附上一个链接： https://https://www.doczj.com/doc/c114484221.html,/hosting/free?spm=5176.8060947.858673.gongxiangpuhu i.794a029dqn9MbW） （ps:别说我打广告啊！我虽然也挺想收广告费的，但是人家也看不上我啊）。
如果打开链接或者自己搜索成功的话应该是这样的页面，以上三个选哪个都不影响，具体作用等着我下次有生之年系列再说。操作系统方面小白建议选windows 系统，windows系统支持https://www.doczj.com/doc/c114484221.html,平台，如果是php开发就选Liunx系统。点击立即购买之后之后付款按钮之类的自己去找找吧，应该在很显眼的位置，毕竟是消费嘛。 显示购买成功之后就看下一步吧！ 1.3怎么找到云主机的操作平台 确定买好了云主机，现在可以看下云主机是怎么操作的了，看网页的右上角有个这样的导航栏 点击控制台，以后在阿里云买的其他东西也可以在控制台看。 点击控制台之后在左上角应该可以看到这样一个侧边栏，点击有三根横线的按钮之后，应该看见这样一个面板 接下来选择域名与网站，因为买的是云主机，与网站相关，这个应该很好理解。在域名与网站中选中云虚拟主机，显示正确的话应该是如下页面
第二章招标项目内容、数量、规格和技术要求 核心数据和核心设备的安全是数据中心管理的重中之重。05年以来我市劳动保障数据中心网络安全防护管理不断加强，陆续配置了防火墙、防毒墙、网闸等安全设备，建立了数据级异地容灾系统，较好地保障了劳动保障网络信息系统的稳定安全运行。但因经费等原因，数据中心在核心设备和核心数据安全防护方面还相对较弱，按照劳动保障网络信息系统安全等级保护的要求和数据中心网络安全管理实际需要，为进一步完善劳动保障网络信息系统安全防护体系，提出本次网络安全设备采购需求。 一、网络安全设备采购需求 （一）网络安全设备采购清单： 分类设备名 称 基本目的基本参数要求 数量 备注 网络安全防御 千兆 防火墙 防护核心数据安 全，提高整个网络 可靠性 2U机架式结构；最大配置不少于24个接口，现 配8个千兆SFP（含4个原厂SFP光模块）和8 个10/100/1000BASE－TX电接口，2个 10/100/1000BASE－TX管理口。要求接口支持STP 协议。网络吞吐量不少于5G，最大并发连接数不 少于200万，每秒最大新建连接数不少于5万， 现配置双电源。 2台原厂 三年 质保 IPS入侵 防御系 统 抵御网络攻击，防 护网络系统安全 1U机架式结构，最大配置不少于24个接口，现 配4个SFP口（含4个原厂SFP光模块）和4个 10/100/1000BASE－TX接口，支持4路Bypass 功能，2个10/100/1000BASE－TX管理口，吞吐 量不少于6G，具有3000条以上的攻击事件，三 年特征库升级服务 1台原厂 三年 质保 网络交换设备24口二 层交换 机 根据网络整合需 要添置，与核心交 换机H3C 9508对 接 H3C S5100-24P-SI 24个10/100/1000Base-T以 太网端口和4个复用的1000Base-X SFP千兆以 太网端口（Combo） 4台原厂 三年 质保
定语从句用法分析 定语从句在整个句子中担任定语，修饰一个名词或代词，被修饰的名词或代词叫先行词。定语从句通常出现在先行词之后，由关系词（关系代词或关系副词）引出。 eg. The boys who are planting trees on the hill are middle school students 先行词定语从句 #1 关系词： 关系代词：who, whom, whose, that, which, as (句子中缺主要成份:主语、宾语、定语、表语、同位语、补语)， 关系副词：when, where, why （句子中缺次要成份：状语）。 #2 关系代词引导的定语从句 关系代词引导定语从句，代替先行词，并在句中充当主语、宾语、定语等主要成分。 1）who, whom, that 指代人，在从句中作主语、宾语。 eg. Is he the man who/that wants to see you?（who/that在从句中作主语） ^ He is the man who/whom/ that I saw yesterday.（who/whom/that在从句中作宾语） ^ 2）whose 用来指人或物，（只用作定语, 若指物，它还可以同of which互换）。eg. They rushed over to help the man whose car had broken down. Please pass me the book whose cover is green. = the cover of which/of which the cover is green. 3）which, that指代物，在从句中可作主语、宾语。 eg. The package （which / that）you are carrying is about to come unwrapped. ^ （which / that在从句中作宾语,可省略） 关系代词在定语从句中作主语时，从句谓语动词的人称和数要和先行词保持一致。 eg. Is he the man who want s to see you? #3.关系副词引导的定语从句 关系副词when, where, why引导定语从句，代替先行词（时间、地点或理由），并在从句中作状语。 eg. Two years ago, I was taken to the village where I was born. Do you know the day when they arrived? The reason why he refused is that he was too busy. 注意： 1）关系副词常常和"介词+ which"结构互换 eg. There are occasions when （on which）one must yield (屈服). Beijing is the place where（in which）I was born. Is this the reason why （for which）he refused our offer? * 2）在非正式文体中，that代替关系副词或"介词+ which"，放在时间、地点、理由的名词，在口语中that常被省略。 eg. His father died the year （that / when / in which）he was born. He is unlikely to find the place （that / where / in which）he lived forty years ago.
主机和服务器 主机和服务器的区别：主机和服务器相当于子文件夹和文件夹一样，一个服务器下面有很多主机。 1.虚拟主机和云主机的区别：主机分为虚拟主机和云主机，虚拟主机需要与其他主机分享整个服务器资源；云主机的资源是独享，可以拥有整个服务器资源分配。 在扩展性上，虚拟主机不支持弹性扩展、按需付费，云服务商一般配置固定的虚拟主机型号来出售，用户可以通过升级不同型号来实现弹性配置；云主机支持全面的弹性扩展，按需付费，自主性高。 在环境搭建上，虚拟主机不需要搭建环境，云服务商已经配置好各种操作系统、建站程序以供选择，用户只需鼠标点击即可实现；云主机需要手动配置环境，搭建架构。 在远程控制上，虚拟主机由于技术原因，无法提供远程桌面功能，仅能通过控制面板系统、FTP软件等方式来管理虚拟主机的功能、文件等；云主机可远程桌面管理，方式灵活多样。在操作性上，虚拟主机操作简单，不懂技术的站长都可以使用，大部分功能集成在控制面板内；云主机操作复杂，需要有一定的服务器运维技术、服务器搭建技术等，对不懂技术的站长会非常吃力。
在价格上、虚拟主机价格便宜，年付1、2百元为主；云主机价格昂贵，年付2-3千为主。 2.云服务器和普通服务器主要区别： 1、定义不同： 云服务器，是简单高效、安全可靠、处理能力可弹性伸缩的计算服务，是一个服务器集群。 普通服务器是一个服务器，位置相对固定，是提供计算服务的硬件设备。 2、配置不同： 云服务器无需提前购买硬件，即可迅速创建或释放任意多台云服务器，一切计算均在云端实现，降低开发运维的难度和整体IT成本。 普通服务器的构成包括处理器、硬盘、内存、系统总线等，和通用的计算机架构类似，费用成本较高。 3、故障率不同： 云服务器是基于服务器集群的，因此硬件冗余度较高，故障率低。 而物理机则相对来说硬件冗余较少，故障率较高。 在企业或者个人建站中，我们可以购买虚拟主机和一个国际域名，主机的空间购买稍微大一点的就够用数年，在价格上也还是较为亲民。
网络安全审计系统的实现方法 1 传统安全审计系统的历史 传统的安全审计系统早在70年代末、80年代初就已经出现在某些UNDO系统当中， 其审计的重点也是本主机的用户行为和系统调用。在随后的20年间，其他的各个操作系统也有了自己的安全审计工具，如符合C2安全级别的Windows NT, Nnux的syslog机制以 及SUN 13SM等。 2 常用安全措施的不足和基于网络的安全审计系统的出现 近几年来，随着开放系统Internet的飞速发展和电子商务的口益普及，网络安全和信息安全问题日益突出，各类黑客攻击事件更是层出不穷。而相应发展起来的安全防护措施也日益增多，特别是防火墙技术以及IDS(人侵检测技术)更是成为大家关注的焦点。但是这两者都有自己的局限性。 2.1防火墙技术的不足 防火墙技术是发展时间最长，也是当今防止网络人侵行为的最主要手段之一，主要有包过滤型防火墙和代理网关型防火墙两类。其主要思想是在内外部网络之间建立起一定的隔离，控制外部对受保护网络的访问，它通过控制穿越防火墙的数据流来屏蔽内部网络的敏感信息以及阻挡来自外部的威胁。虽然防火墙技术是当今公认发展最为成熟的一种技术，但是由于防火墙技术自身存在的一些缺陷，使其越来越难以完全满足当前网络安全防护的要求。 包过滤型防火墙如只实现了粗粒度的访问控制，一般只是基于IP地址和服务端口，对网络数据包中其他内容的检查极少，再加上其规则的配置和管理极其复杂，要求管理员对网络安全攻击有较深人的了解，因此在黑客猖撅的开放Internet系统中显得越来越难以使用。 而代理网关防火墙虽然可以将内部用户和外界隔离开来，从外部只能看到代理服务器而看不到内部任何资源，但它没有从根本上改变包过滤技术的缺陷，而且在对应用的支持和速度方面也不能令人满意 2.2入侵检测技术的不足 人侵检测技术是防火墙技术的合理补充，能够对各种黑客人侵行为进行识别，扩展了网络管理员的安全管理能力。一般来说，人侵检测系统(IDS)是防火墙之后的第二层网络安全 防护机制。 目前较为成熟的IDS系统可分为基十主机的IDS和基于网络的IDS两种。
comparison的用法解析大全 comparison的意思是比较，比喻，下面我把它的相关知识点整理给大家，希望你们会喜欢！ 释义 comparison n. 比较;对照;比喻;比较关系 [ 复数 comparisons ] 词组短语 comparison with 与…相比 in comparison adj. 相比之下;与……比较 in comparison with 与…比较，同…比较起来 by comparison 相比之下，比较起来 comparison method 比较法 make a comparison 进行比较 comparison test 比较检验 comparison theorem 比较定理 beyond comparison adv. 无以伦比 comparison table 对照表 comparison shopping 比较购物;采购条件的比较调查 paired comp arison 成对比较 同根词 词根： comparing adj. comparative 比较的;相当的 comparable 可比较的;比得上的 adv. comparatively 比较地;相当地 comparably 同等地;可比较地 n.
comparative 比较级;对手 comparing 比较 comparability 相似性;可比较性 v. comparing 比较;对照(compare的ing形式) 双语例句 He liked the comparison. 他喜欢这个比喻。 There is no comparison between the two. 二者不能相比。 Your conclusion is wrong in comparison with their conclusion. 你们的结论与他们的相比是错误的。 comparison的用法解析大全相关文章： 1.by的用法总结大全
金融行业 运维安全审计系统技术白皮书 东华软件股份公司 2011年4月
目录 1.........................................................................................................................................审计要求 1 2解决之道 (2) 2.1HAC简介 (2) 2.2应用环境 (2) 2.3认证资质 (3) 3产品介绍 (4) 3.1系统功能 (4) 3.1.1完整的身份管理和认证 (4) 3.1.2灵活、细粒度的授权 (4) 3.1.3后台资源自动登陆 (4) 3.1.4实时监控 (5) 3.1.5违规操作实时告警与阻断 (5) 3.1.6完整记录网络会话过程 (5) 3.1.7详尽的会话审计与回放 (6) 3.1.8完备的审计报表功能 (6) 3.1.9各类应用运维操作审计功能 (6) 3.1.10可结合ITSM（IT服务管理） (7) 3.1.11其他功能 (7) 3.2系统部署 (7) 3.3系统特点 (9) 3.3.1支持Unix和W indows平台下运维操作审计 (9) 3.3.2更严格的审计管理 (9) 3.3.3分权管理机制 (9) 3.3.4部署灵活、操作方便 (9) 3.3.5完善的系统安全设计 (9) 3.4与网络审计类产品比较 (9)
4技术指标 (11) 4.1型号说明 (11) 4.2HAC1000接口配置 (13) 4.3HAC1000兼容性 (13) 5典型案例 (14) 5.1现状描述 (14) 5.2部署方案 (15) 5.3方案特点 (15)
基于语料库的“人家”用法分析 “人家”是北方方言中口语化的指称代词，语义非常丰富。不同的指称用法蕴含说话人不同的情感态度，如称羡讽刺、同情自怜，从而达到不同的语用效果，即语用移情或语用离情的效果。本文借助于语料库，为分析“人家”的用法及语用效果提供了科学的支撑和有力的支持。 标签：“人家” 语用效果语用功能 一、引言 “人家”既可以用作旁指代词，虚指除自己以外的“别人”，又可以用作第三人称代词，实指“他”或“他们”，也可以和“人家”后面的名词性成分构成同位语，有复指的用法。此外，“人家”还可以用来指称自己或是听话人“你”或“您”。“人家”有如此丰富的指称用法蕴含了说话人怎样的情感态度？本文从语用学的角度，借助语料库这一工具对“人家”一词的用法进行具体分析。 （一）研究内容 本文要探讨的问题如下：1.“人家”的具体用法有哪些？哪些常用，哪些不常用？2.“人家”在不同的语境、不同的用法中主要表达说话人怎样的情感态度？ 3.“人家”在使用中语用移情功能多还是语用离情功能多？ 笔者认为，“人家”不同指称义的使用，直接体现着言者对不同人际关系的评判，蕴含着言者不同的情感态度。过去对“人家”的研究主要集中在句法层面和语义层面，从语用层面进行分析研究的相对匮乏，并且大多只是从少量例子出发，作出概括分析，带有强烈的主观色彩。因此借用语料库这一工具，对“人家”的用法及语用效果进行科学客观的分析，是本文的根本出发点。 （二）研究方法 本文首先利用国家语委现代汉语平衡语料库检索出1794个包含“人家”的语料。其次，利用Concordance Sampler抽样软件，抽取出500个样本逐个进行分析，剔除不符合条件的名词用法，剩余404个“人家”作代词的语料。再次，通过人工标记的方法，按照指称对象的不同，对“人家”的用法进行分类。最后，由于“人家”的基本义“别人”使用时比较客观，不带感情色彩，因而笔者对“人家”其余四种用法的166个语料一一分析了其表达的说话人的情感倾向，进而分析其语用表达效果。 二、“人家”的用法分析 “人家”的归属问题，历来备受争议。本文综合各家之言，将“人家”的用法分为5类：1.旁指；2.复指；3.第一人称；4.第二人称；5.第三人称。通过对所得语
云主机与传统主机的对比分析报告 ——企商在线云主机分析 关于云主机与传统的主机之间的区别，大家对其认识多少呢又有何看法呢？企商在线专职优化、域名注册、网站空间、虚拟主机、服务器托管、云主机、服务器租用、光纤。可以试着参考一下： 1. 什么是云主机？ 云主机是云计算服务体系中的一项主机产品，该产品有效的解决了传统物理租机与VPS服务中，存在的管理难度大，业务扩展性弱的缺陷。在实际应用中的云主机具有三个方面的弹性能力： 主机服务配置与业务规模可根据用户的需要进行配置，并可灵活的进行调整。用户申请的主机服务可以实现快速供应和部署(实时在线开通)，实现了集群内弹性可伸缩计费方式灵活，用户无需支付押金，且有多种支付方式供用户选择。 2. 云计算平台适合什么样的用户？ 注重主机服务性价比的用户；需要快速实现分布式部署的用户；对业务的弹性扩展能力有需求的用户；有系统高可用性和快速恢复需求的用户；希望轻松管理系统的用户。支持电子商务、论坛、SNS、企业网站、OA系统等互联网应用；禁止私服、色情、外挂等非法应用，一经发现，立即关闭。 3. 与VPS相比，云主机的主要优势是什么？ 用户可以方便的进行远程维护，免费重装系统硬件级别上实现云主机之间的完全隔离；内置冗
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