In the relationship of education to business we observe today a fine state of paradox. On the one hand, the emphasis which most business places upon a college degree is so great that one can almost visualize the time when even the office boy will have his baccalaureate. On the other hand, we seem to preserve the belief that some deep intellectual chasm separates the businessman from other products of the university system. The notion that business people are quite the Philistines sounds absurd. For some reason, we tend to characterize vocations by stereotypes, none too flattering but nonetheless deeply imbedded in the national conscience. In the cast of characters the businessman comes on stage as an ill-mannered and simple minded person. It is not a pleasant conception and no more truthful or less unpleasant than our other stereotypes. Business is made up of people with all kinds of backgrounds, all kinds of motivations, and all kinds of tastes, just as in any other form of human endeavor. Businessmen are not mobile balance sheets and profit statements, but perfectly normal human beings, subject to whatever strengths, frailties, and limitations that characterize man on the earth. They are people grouped together in organizations designed to complement the weakness of one with strength of another, tempering the exuberance of the young with the caution of the more mature, the poetic soarings of one mind with the counting house realism of another. Any disfigurement which society may suffer will come from man himself, not from the particular vocation to which he devotes his time. Any group of people necessarily represents an approach to a common one, and it is probably true that even individually they tend to conform somewhat to the general pattern. Many have pointed out the danger of engulfing our original thinkers in a tide of mediocrity. Conformity is not any more prevalent or any more exacting in the business field than it is in any other. It is a characteristic of all organizations of whatever nature. The fact is the large business unit provides greater opportunities for individuality and requires less in the way of conformity than other institutions of comparable size—the government, or the academic world, or certainly the military.According to the last paragraph, which of the following is true

设fx+1=afx总成立f’0=bab为非零常数则fx在x=1处______

设随机变量X与Y分别服从N-12和N12且X与Y不相关k1X+Y与X+k2Y也不相关则______

求微分方程Y+5y’+6y=2e-x的通解

LongbeforeManlivedontheEarththerewerefishesreptilesbirdsinsectsandsomemammals.Althoughsomeoftheseanimalswereancestorsofkindslivingtodayothersarenowextinctthatistheyhavenodescendantsalivenow.41Veryoccasionallytherocksshowimpressionofskinsothatapartfromcolorwecanbuildupareasonablyaccuratepictureofananimalthatdiedmillionsofyearsago.Thatkindofrockinwhichtheremainsarefoundtellsusmuchaboutthenatureoftheoriginallandoftenoftheplantsthatgrewonitandevenofitsclimate.42Nearlyallofthefossilsthatweknowwerepreservedinrocksformedbywateractionandmostoftheseareofanimalsthatlivedinornearwater.Thusitfollowsthattheremustbemanykindsofmammalsbirdsandinsectsofwhichweknownothing.43Therewerealsocrablikecreatureswhosebodieswerecoveredwithahornysubstance.Thebodysegmentseachhadtwopairsoflegsonepairforwalkingonthesandybottomtheotherforswimming.Theheadwasakindofshieldwithapairofcompoundeyesoftenwiththousandsoflenses.Theywereusuallyaninchortwolongbutsomewere2feet.44Ofthesetheammonitesareveryinterestingandimportant.Theyhaveashellcomposedofmanychamberseachrepresentingatemporaryhomeoftheanimal.Astheyounggrewlargeritgrewanewchamberandsealedoffthepreviousone.ThousandsofthesecanbeseenintherocksontheDorsetCoast.45About75millionyearsagotheAgeofReptileswasoverandmostofthegroupsdiedout.Themammalsquicklydevelopedandwecantracetheevolutionofmanyfamiliaranimalssuchastheelephantandhorse.Manyofthelatermammalsthoughnowextinctwereknowntoprimitivemanandwerefeaturedbyhimincavepaintingsandonbonecarvings.A.Theshellfishhavealonghistoryintherockandmanydifferentkindsareknown.B.Neverthelessweknowagreatdealaboutmanyofthembecausetheirbonesandshellshavebeenpreservedintherocksasfossilsfromthemwecantelltheirsizeandshapehowtheywalkedthekindoffoodtheyate.C.Thefirstanimalswithtruebackboneswerethefishesfirstknownintherocksof375millionyearsago.About300millionyearsagotheamphibianstheanimalsabletolivebothonlandandinwaterappeared.Theyweregiantsometimes8feetlongandmanyofthemlivedintheswampypoolsinwhichourcoalseamorlayerisformed.Theamphibiansgaverisetothereptilesandfornearly150millionyearstheseweretheprincipalformsoflifeonlandintheseaandintheair.D.Thebestindexfossilstendtobemarinecreatures.Theseanimalsevolvedrapidlyandspreadoverlargeoverlargeareasoftheworld.E.Theearliestanimalswhoseremainshavebeenfoundwereallverysimplekindsandlivedinthesea.Laterformsaremorecomplexandamongthesearethesea-liliesrelationsofthestar-fisheswhichhadlongarmsandwereattachedbyalongstalktotheseabedortorocks.F.Whenananimaldiesthebodyitsbonesorshellmayoftenbecarriedawaybystreamsintolakesortheseaandthengetcoveredupbymud.Iftheanimallivedintheseaitsbodywouldprobablysinkandbecoveredwithmud.Moreandmoremudwouldfalluponituntilthebonesorshellbecomeembeddedandpreserved.G.Manyfactorscaninfluencehowfossilsarepreservedinrocks.Remainsofanorganismmaybereplacedbymineralsdissolvedbyanacidicsolutiontoleaveonlytheirimpressionorsimplyreducedtoamorestableform.

设函数z=zxy是由方程z=2y+e2x-3z确定则______

46AnydiscussionoftheAmericaneducationalsystemwouldbelessthancompleteifitdidnotmentiontheemphasisthatmanycollegesanduniversitiesplaceuponthenonacademicsocialextracurricularaspectofeducationoftendefinedaspersonalgrowth.Perhapsausefulwayofviewingthenotionofpersonalgrowthwouldbetopicturetheverylargeandgeneraltermeducationasbeingall-embracingincludingassubsetswithinitacademicandnonacademiccomponents.ThismaybeoneofthemostdifficultconceptstoconveytosomeonewhoisnotintimatelyfamiliarwithAmericanhighereducation.Feweducationalsystemsinothercountriesplacethesameemphasisonthisblendofacademicandpersonaleducation.ThemajorityofcollegesanduniversitiesintheUnitedStatesmakesomeattempttointegratepersonalandintellectualgrowthintheundergraduateyears.47IftheultimategoalofundergraduateeducationinAmericaweresimplytoconveyasetbodyofknowledgethetermofstudiescouldundoubtedlybereduced.Yetthetermsofstudiesareextendedinordertogivestudentsachancetogrowanddevelopinotherways.Numerousopportunitiesaremadeavailabletostudentstobecomeinvolvedinsportsstudentgovernmentmusicalanddramaticorganizationsandcountlessotherorganizedandindividualactivitiesdesignedtoenhanceone’spersonalgrowthandprovidesomerecreationandenjoymentoutsideoftheclassroom.48Experiencewithcampusorganizationsandoff-campuscommunityinvolvementcanbehighlyvaluableinpreparinginternationalstudentsforfutureleadershipintheirprofessionalfieldupontheirreturnhome.ThetypicalAmericancollege’ssupportforextracurricularactivityisperhapsuniqueintheworld.ThisspecialeducationaldimensionbeyondtheclassroomandlaboratoryexperiencedoesnotmeanthatextracurricularparticipationisrequiredtogainanAmericandegree.Itremainsanentirelyoptionalactivitybut49itisnotedherebecauseAmericanshavetraditionallyviewedsuccessinone’sroleasacitizenascloselylinkedtoawell-roundedlifethatincorporatesavarietyofsocialathleticandculturalactivitiesintoaperson’sexperience.AgreatmanyAmericancampusesandcommunitieshaveorganizedspecialextracurricularactivitiesforstudentsfromothercountries.50OnmostcampusesonecanfindaninternationalclubwhichincludesAmericanswherestudentscangettoknowandlearnsociallyfromstudentsfromothercountriesaswellasAmericans.InternationalstudentsarealmostalwaysinvitedthroughorganizedhospitalityactivitiesintothehomesofAmericanslivinginoroutsidetheacademiccommunity.

由方程所确定的函数z=zxy在点10-1处的全微分dz=______

设总体X服从于正态分布Nμσ2σ＞0从该总体中抽取简单随机样本X1X2X2nn≥2其样本均值为求统计量Y=的数学期望EY

设X1X2Xn是总体N01的简单随机样本记T=则ET的值为______

设AB为n阶对称矩阵下列结论不正确的是______

设n=12则下列级数中肯定收敛的是______

AB均是n阶矩阵且A2-2AB=E则秩rAB-BA+A=______．

Societyexiststhroughaprocessoftransmission.Thistransmissionoccursbymeansofcommunicationofhabitsofdoingthinkingandfeelingfromtheoldertotheyounger.Soobviousisthenecessityofteachingandlearningforthecontinuedexistenceofasocietythatwemayseemtobedwellingexcessivelyonaself-evidenttruth.Butjustificationisfoundinthefactthatsuchemphasisisameansofgettingusawayfromanundulyscholasticandformalnotionofeducation.Schoolsareindeedoneimportantmethodofthetransmissionwhichformsthedispositionsoftheimmature;butitisonlyonemeansandcomparedwithotheragenciesarelativelysuperficialmeans.Onlyaswehavegraspedthenecessityofmorefundamentalandpersistentmodesoftuitioncanwemakesureofplacingthescholasticmethodsintheirtruecontext.Societynotonlycontinuestoexistbytransmissionbycommunicationbutitmayfairlybesaidtoexistintransmissionincommunication.Allcommunicationandhenceallgenuinesociallifeiseducative.Tobearecipientofacommunicationistohaveanenlargedandchangedexperience.Onesharesinwhatanotherhasthoughtandfeltandinsofarmeagerlyoramplyhashisownattitudemodified.Noristheonewhocommunicatesleftunaffected.Trytheexperimentofcommunicatingwithfullnessandaccuracysomeexperiencetoanotherespeciallyifitbesomewhatcomplicatedandyouwillfindyourownattitudetowardyourexperiencechanging;otherwiseyouresorttoswearwordsandexclamations.Theexperiencehastobeformulatedinordertobecommunicated.ToformulaterequiresgettingoutsideofitseeingitasanotherwouldseeitconsideringwhatpointsOfcontactithaswiththelifeofanothersothatitmaybegotintosuchformthathecanappreciateitsmeaning.Exceptindealingwithcommonplacesandcatchphrasesonehastoassimilateimaginativelysomethingofanother’sexperienceinordertotellhimintelligentlyofone’sownexperience.Allcommunicationislikeart.Itmayfairlybesaidthereforethatanysocialarrangementthatremainsvitallysocialorvitallysharediseducativetothosewhoparticipateinit.Onlywhenitbecomescastinamoldandrunsinaroutinewaydoesitloseitseducativepower.

Whereverpeoplehavebeentheyhaveleftwastebehindwhichcancauseallsortsofproblems.Wasteoftenstinksattractsverminandcreateseyesores.Moreseriouslyitcanreleaseharmfulchemicalsintothesoilandwaterwhendumpedorintotheairwhenburned.Andthentherearesomereallynastyformsofindustrialwastesuchasspentnuclearfuelforwhichnouniversallyaccepteddisposalmethodshavethusfarbeendeveloped.Yetmanyalsoseewasteasanopportunity.Gettingridofitallhasbecomeahugeglobalbusiness.Richcountriesspendsome$120billionayeardisposingoftheirmunicipalwastealoneandanother$150billiononindustrialwaste.Theamountofwastethatcountriesproducetendstogrowintandemwiththeireconomiesandespeciallywiththerateofurbanization.SowastefirmsseearichfutureinplacessuchasChinaIndiaandBrazilwhichatpresentspendonlyabout$5billionayearcollectingandtreatingtheirmunicipalwaste.Wastealsopresentsanopportunityinagrandersense:asapotentialresource.Muchofitisalreadyburnedtogenerateenergy.Clevernewtechnologiestoturnitintofertiliserorchemicalsorfuelarebeingdevelopedallthetime.Visionariesseeaworldwithoutwastewithrubbishbeingroutinelyrecycled.Untillastsummersuchviewswerespreadingquickly.Butsincethenplummetingpricesforvirginpaperplasticandfuelsandhencealsoforthewastethatsubstitutesforthemhaveputanendtosuchvisions.Manyoftherecyclingfirmsthathadarguedrubbishwasonthewayoutnowsaythatunlesstheyaregivenfinancialhelptheythemselveswilldisappear.Subsidiesareabadidea.Governmentshavearoletoplayinthebusinessofwastemanagementbutitisaregulatoryandsupervisoryone.Theyshouldobligepeoplewhocreatewastetocleanupafterthemselvesandideallyensurethatthepriceofanyproductreflectsthecostofdisposingofitsafely.Thatwouldhelptosignalwhichitemsarehardesttogetridofgivingconsumersanincentivetobuygoodsthatcreatelesswasteinthefirstplace.Thatmaysoundsimpleenoughbutgovernmentsseldomgettherolesright.Inpoorercountriestheyoftenhavenorulesatalloriftheyhavethemtheyfailtoenforcethem.Inrichcountriestheyareofteninconsistent:toostrictaboutsomesortsofwasteandworryinglylaxaboutothers.Theyarealsopronetoimposingarbitrarytargetsandtaxes.Californiaforexamplewantstorecycleallitstrashnotbecauseitnecessarilymakesenvironmentaloreconomicsensebutbecausethegoalofzerowastesoundspoliticallyattractive.Whichofthefollowingistrueaccordingtothelastparagraph

设X1X2Xn为来自总体N0σ2的样本则样本二阶原点矩的方差为______

TheTreasurycouldpocket20millionayearinextrafinesoncethecountry’sspeedcameranetworkisexpanded.Motoringorganizationswarnedthatthe1couldbecomeapolltaxonwheels2hugenumberofdrivers.Therecouldbemanymoreincidentsofvandalism3cameras.Thewarningscame4aDailyMailsurveyfoundalmostallthe23policeforcesinEnglandandWaleswereeither5toexpansionplansorconsidering6. Nationwidethenumberofspeedingticketsisexpectedtotreble790millionayear.8theschemepolicekeepsomeofthecashfromfinesto9thecostsoffittingandmaintainingextracamerasand10thatexistingonesalwayshavefilminthem.TherestwillgototheTreasury.BothMinistersandpoliceinsisttheschemeisaimed11atmakingroadssafer.Theypointtotrialsineightareaswhichcutcollisionsbyaquarteranddeathsandseriousinjuriesby12ahalf. Butmotoringorganizationsfearcameraswillbesitedonrelativelysafe13faststretchestocatchasmanydriversaspossible.Someforcesarealsoexpectedto14thethresholdspeedsatwhichcamerasare15totheabsolutelegalminimum-15mphina10mphlimitand26mphina20mphzone.Thiscouldencouragedriverstostareattheirspeedometersinsteadofconcentratingontheroadand16tomoreaccidents.SueNicholsonheadofcampaignsattheRACsaidWedon’thaveaproblemwithspeedcameras17.Butwedohaveconcernsabout18theyaresited.Policerisklosingcredibility19motoristsifcamerasareseenasrevenue-raising20safetydevices./ 13

已知线性方程组AX=kβ1+β2有解其中A=则k等于______

设fx在-∞0]上连续且满足求fx及其极小值

设fx在ab内可微且fa=fb=0f’a＜0f’b＜0则方程f’x=0在ab内______．

TheTreasurycouldpocket20millionayearinextrafinesoncethecountry’sspeedcameranetworkisexpanded.Motoringorganizationswarnedthatthe1couldbecomeapolltaxonwheels2hugenumberofdrivers.Therecouldbemanymoreincidentsofvandalism3cameras.Thewarningscame4aDailyMailsurveyfoundalmostallthe23policeforcesinEnglandandWaleswereeither5toexpansionplansorconsidering6. Nationwidethenumberofspeedingticketsisexpectedtotreble790millionayear.8theschemepolicekeepsomeofthecashfromfinesto9thecostsoffittingandmaintainingextracamerasand10thatexistingonesalwayshavefilminthem.TherestwillgototheTreasury.BothMinistersandpoliceinsisttheschemeisaimed11atmakingroadssafer.Theypointtotrialsineightareaswhichcutcollisionsbyaquarteranddeathsandseriousinjuriesby12ahalf. Butmotoringorganizationsfearcameraswillbesitedonrelativelysafe13faststretchestocatchasmanydriversaspossible.Someforcesarealsoexpectedto14thethresholdspeedsatwhichcamerasare15totheabsolutelegalminimum-15mphina10mphlimitand26mphina20mphzone.Thiscouldencouragedriverstostareattheirspeedometersinsteadofconcentratingontheroadand16tomoreaccidents.SueNicholsonheadofcampaignsattheRACsaidWedon’thaveaproblemwithspeedcameras17.Butwedohaveconcernsabout18theyaresited.Policerisklosingcredibility19motoristsifcamerasareseenasrevenue-raising20safetydevices./ 7

设A=ijn×n是正交矩阵将A以行分块为A=α1α2αnT则方程组AX=bb=b1bnT的通解为______

已知随机变量X和Y相互独立则X～N11Y～N14又PaX+bY≤0=则a与b应满足关系式______

Donotsignyourownnameattheendoftheletter.UseDepartmentofChineseLanguageandLiteratureinstead. Donotwritetheaddress.

Chronicinsomniaisamajorpublichealthproblem.Andtoomanypeopleareusing1therapiesevenwhilethereareafewtreatmentsthatdowork.MillionsofAmericans2awakeatnightcountingsheeporhaveastiffdrinkor3anpillhopingitwillmakethemsleepy.4expertsagreeallthatself-medicatingisabadideaandthecausesofchronicinsomniaremain5.a Chronicinsomniaisamajorpublichealthproblem.Andtoomanypeopleareusing1therapiesevenwhilethereareafewtreatmentsthatdowork.MillionsofAmericans2awakeatnightcountingsheeporhaveastiffdrinkor3anpillhopingitwillmakethemsleepy.4expertsagreeallthatself-medicatingisabadideaandthecausesofchronicinsomniaremain5. Almostathirdofadultshavetroublesleepingandabout10percenthave6ofdaytimeimpairmentthatsignaltrueinsomnia.But7thecomplaintsscientistsknowsurprisinglylittleaboutwhatcauseschronicinsomniaitshealthconsequencesandhowbesttotreatitapanelofspecialists8togetherbytheNationalInstitutesofHealthconcludedWednesday.Thepanelcalled9abroadrangeofresearchintoinsomnia10thatifscientistsunderstoodits11causestheycoulddevelopbettertreatments. Mostbutnotallinsomniaisthoughtto12otherhealthproblemsfromarthritisanddepressiontocardiovasculardisease.Thequestionofteniswhethertheinsomniacamefirstorwasaresultoftheotherdiseasesandhowtroublesleepingin13complicatesthoseotherproblems.Otherdiseases14theriskofinsomniaseemstoincreasewithageandtobemore15amongwomenespeciallyaftertheir50s.Smokingcaffeineandnumerous16drugsalsoaffectsleep. TheNIHisspendingabout$200millionthisyearonsleep-relatedresearchsome17tospecificdisordersandothers18theunderlyingscientificlawsthatcontrolthenervoussystemofsleep.Theagencywas19thepane’sreviewbeforedecidingwhatadditionalworkshouldbe20atinsomnia. 15

设随机变量X的分布函数为对X独立观测3次则3次结果都不超过1的概率为______．

设fuv具有连续偏导数且f’uuv+f’vuv=sinu+veu+v求yx=e-2xfxx所满足的一阶微分方程并求其通解

二次型fx1x2x3=x12+4x22+4x32-4x1x2+4x1x3-8x2x3的规范型是______

若|f’x|＜g’xx≥a则当x＞a时必有______

设A是n阶正定矩阵E是n阶单位阵证明A+E的行列式大于1

方程=0在区间01内的实根个数为______

TheTreasurycouldpocket20millionayearinextrafinesoncethecountry’sspeedcameranetworkisexpanded.Motoringorganizationswarnedthatthe1couldbecomeapolltaxonwheels2hugenumberofdrivers.Therecouldbemanymoreincidentsofvandalism3cameras.Thewarningscame4aDailyMailsurveyfoundalmostallthe23policeforcesinEnglandandWaleswereeither5toexpansionplansorconsidering6. Nationwidethenumberofspeedingticketsisexpectedtotreble790millionayear.8theschemepolicekeepsomeofthecashfromfinesto9thecostsoffittingandmaintainingextracamerasand10thatexistingonesalwayshavefilminthem.TherestwillgototheTreasury.BothMinistersandpoliceinsisttheschemeisaimed11atmakingroadssafer.Theypointtotrialsineightareaswhichcutcollisionsbyaquarteranddeathsandseriousinjuriesby12ahalf. Butmotoringorganizationsfearcameraswillbesitedonrelativelysafe13faststretchestocatchasmanydriversaspossible.Someforcesarealsoexpectedto14thethresholdspeedsatwhichcamerasare15totheabsolutelegalminimum-15mphina10mphlimitand26mphina20mphzone.Thiscouldencouragedriverstostareattheirspeedometersinsteadofconcentratingontheroadand16tomoreaccidents.SueNicholsonheadofcampaignsattheRACsaidWedon’thaveaproblemwithspeedcameras17.Butwedohaveconcernsabout18theyaresited.Policerisklosingcredibility19motoristsifcamerasareseenasrevenue-raising20safetydevices./ 5

设微分方程yx是方程Y+x-1Y’+x2y=ex满足y0=0y’0=1的解则______

Donotsignyourownnameattheendoftheletter.UseLiMinginstead. Donotwritetheaddress

用配方法化二次型fxyz=x2+2y2+5z2+2xy+6yz+2zx为标准形并求所用的可逆线性变换．

已知f’x=arctanx-12f0=0则fxdx=______．

Inathree-monthperiodlastyeartwoBrooklyniteshadtobecutoutoftheirapartmentsandcarriedtohospitalonstretchersdesignedfortransportingsmallwhales.TheNationalAssociationtoAdvanceFatAcceptanceNAAFAarguesthatitwasnottheircombined900kgbulkthatmadethemill.ObesityaccordingtoNAAFAisnotbadforyou.Andevenifitwasthereisnothingtobedoneaboutitbecausegenesdictateweight.Attemptingtoeatlessmerelyslowsmetabolismhavingpeopleaschubbyasever.ThisisthefatlashmovementthatcausesAmerica’sslimmingindustrysomuchpain.InhisbookBinFatLiesBallantine1996GlennGaessersaysthatnostudyyethasconvincinglyshownthatweightisanindependentcauseofhealthproblems.Fatnessdoesnotkillpeople;thingslikehypertensioncoronaryheartdiseasesandcancerdo.MichaelFumentoauthorofTheFatoftheLandViking1997ananti-fatlashdiatribecomparesDrGaesser’slogicwithsayingthattheguillotinedidnotkillLouisXVI:Ratheritwastheseveringofhisvertebraethecuttingofallthebloodvesselsinhisneckand..thetraumacausedbyhisheaddroppingseveralfeetintoawickerbasket.Beingfatkillsinseveralways.Itmakespeoplefarmorelikelytosufferfromheartdiseaseorhighbloodpressure.Evenmoderateobesityincreasesthechanceofcontractingdiabetes.Being40%overweightmakespeople30%-50%morelikelytodieofcanceraccordingtotheAmericanCancerSociety.Extremefatnessmakespatientssomuchlesslikelytosurvivesurgerythatmanydoctorsrefusetooperateuntiltheyslim.Theideathatbeingoverweightiscausedbyobesitygenesisnotwhollyfalse:researchershavefoundanumberofgenesthatappeartomakesomepeoplebumoffenergyataslowerrate.Butgenesarenotdestiny.Thedifferencebetweensomeonewithageneticpredispositiontogainweightandsomeonewithoutappearstoberoughly40calories—oraspoonfulofmayonnaise—aday.AnalternativefatlashargumentadvancedinbookssuchasDeanOnrush’sEatMoreWeightLessHarperCollies1993andDateAtrens’sDon’tDietWilliamMorrow1978isthatfatnessisnotamatterofeatingtoomuch.TheynotethatasAmericans’weighthasballoonedoverthelastfewdecadestheirreportedcaloricintakehasplunged.Thissimplyexplainspeople’sownrecollectionofhowmuchtheyeatisextremelyunreliable.Andastheygrowfatterpeoplefeelguiltyandaremorelikelytofibabouthowmuchtheyeat.Allreputablestudiesshowthateatinglessandexercisingreduceweight.Certainlythebody’smetabolismslowsalittlewhenyouloseweightbecauseittakeslessenergytocarrylessbulkaroundandbecausedietingcanmakethebodyfearitisabouttostarve.Butasensiblelow-fatdietmakesweightlosspossible.Thefatlashmovementisdangerousbecauseslimmerswilloftenfindanyexcusetogiveup.Totellpeoplethatitishealthytobeobeseistoencouragethemtolivesickanddieyoung.Whichofthefollowingstatementsistrue

假设一部机器在一天内发生故障的概率为0.2机器发生故障时全天停止工作若一周5个工作日里无故障可获利润10万元发生一次故障仍可获利润5万元发生二次故障所获利润为0元发生三次或三次以上故障就要亏损2万元求一周内期望利润是多少

设α1=1231Tα2=112-1Tα3=13a3Tα4=357-1Tβ=011bTⅠ当ab满足什么条件时β可由α1α2α3α4线性表示且表示式唯一Ⅱ当ab满足什么条件时β可由α1α2α3α4线性表示且表示式不唯一并求出β的表示式

Inathree-monthperiodlastyeartwoBrooklyniteshadtobecutoutoftheirapartmentsandcarriedtohospitalonstretchersdesignedfortransportingsmallwhales.TheNationalAssociationtoAdvanceFatAcceptanceNAAFAarguesthatitwasnottheircombined900kgbulkthatmadethemill.ObesityaccordingtoNAAFAisnotbadforyou.Andevenifitwasthereisnothingtobedoneaboutitbecausegenesdictateweight.Attemptingtoeatlessmerelyslowsmetabolismhavingpeopleaschubbyasever.ThisisthefatlashmovementthatcausesAmerica’sslimmingindustrysomuchpain.InhisbookBinFatLiesBallantine1996GlennGaessersaysthatnostudyyethasconvincinglyshownthatweightisanindependentcauseofhealthproblems.Fatnessdoesnotkillpeople;thingslikehypertensioncoronaryheartdiseasesandcancerdo.MichaelFumentoauthorofTheFatoftheLandViking1997ananti-fatlashdiatribecomparesDrGaesser’slogicwithsayingthattheguillotinedidnotkillLouisXVI:Ratheritwastheseveringofhisvertebraethecuttingofallthebloodvesselsinhisneckand..thetraumacausedbyhisheaddroppingseveralfeetintoawickerbasket.Beingfatkillsinseveralways.Itmakespeoplefarmorelikelytosufferfromheartdiseaseorhighbloodpressure.Evenmoderateobesityincreasesthechanceofcontractingdiabetes.Being40%overweightmakespeople30%-50%morelikelytodieofcanceraccordingtotheAmericanCancerSociety.Extremefatnessmakespatientssomuchlesslikelytosurvivesurgerythatmanydoctorsrefusetooperateuntiltheyslim.Theideathatbeingoverweightiscausedbyobesitygenesisnotwhollyfalse:researchershavefoundanumberofgenesthatappeartomakesomepeoplebumoffenergyataslowerrate.Butgenesarenotdestiny.Thedifferencebetweensomeonewithageneticpredispositiontogainweightandsomeonewithoutappearstoberoughly40calories—oraspoonfulofmayonnaise—aday.AnalternativefatlashargumentadvancedinbookssuchasDeanOnrush’sEatMoreWeightLessHarperCollies1993andDateAtrens’sDon’tDietWilliamMorrow1978isthatfatnessisnotamatterofeatingtoomuch.TheynotethatasAmericans’weighthasballoonedoverthelastfewdecadestheirreportedcaloricintakehasplunged.Thissimplyexplainspeople’sownrecollectionofhowmuchtheyeatisextremelyunreliable.Andastheygrowfatterpeoplefeelguiltyandaremorelikelytofibabouthowmuchtheyeat.Allreputablestudiesshowthateatinglessandexercisingreduceweight.Certainlythebody’smetabolismslowsalittlewhenyouloseweightbecauseittakeslessenergytocarrylessbulkaroundandbecausedietingcanmakethebodyfearitisabouttostarve.Butasensiblelow-fatdietmakesweightlosspossible.Thefatlashmovementisdangerousbecauseslimmerswilloftenfindanyexcusetogiveup.Totellpeoplethatitishealthytobeobeseistoencouragethemtolivesickanddieyoung.Whatcanbeconcludedaccordingtotheauthor’sviewoftheobesitygenes

Themythologyofaculturecanprovidesomevitalinsightsintothebeliefsandvaluesofthatculture.Byusingfantasticandsometimesincrediblestoriestocreateanoraltraditionbywhichtoexplainthewondersofthenaturalworldandteachlessonstoyoungergenerationsasocietyexposesthoseideasandconceptsheldmostimportant.Justasimportantasthefinallessontobegatheredfromthestorieshoweverarethecharactersandtherolestheyplayinconveyingthatmessage.PerhapstheepitomeofmythologyanditsuseasatooltopassonculturalvaluescanbefoundinAesop’sFablestoldandretoldduringtheeraoftheGreekEmpire.Aesopaslavewhowonthefavorofthecourtthroughhisimaginativeanddescriptivetalesalmostexclusivelyusedanimalstofilltherolesinhisshortstories.Humanswhenatallpresentalmostalwaysplayedthepartofbumblingfoolsstrugglingtolearnthelessonbeingpresented.ThischoiceofcharacterizationallowsustoseethattheGreeksplacedwisdomonalevelslightlybeyondhumansimplyingthatdeepwisdomandunderstandingisauniversalqualitysoughtbyratherthansteanningfromhumanbeings.Aesop’sfablesillustratedthecentralthemesofhumilityandself-reliancereflectingtheimportanceofthosetraitsinearlyGreeksociety.Thefollyofhumanswasusedtocontrastagainsttheultimategoalofattainingahigherlevelofunderstandingandawarenessoftruthsaboutnatureandhumanity.Forexampleonenotablefablefeaturesafoxrepeatedlytryingtoreachabunchofgrapesonaveryhighvine.Afterfailingatseveralattemptsthefoxgivesupmakingupitsmindthatthegrapeswereprobablysouranyway.Thefable’slessonthatweoftenplaydownthatwhichwecan’tachievesoastomakeourselvesfeelbetterteachesthereaderorlistenerinanentertainingwayaboutoneoftheweaknessesofthehumanpsyche.ThemythologyofotherculturesandsocietiesrevealtheunderlyingtraitsoftheirrespectiveculturesjustasAesop’sfablesdid.ThestoriesofRomangodsAztecghostsandEuropeanelvesallservedtotrainancientgenerationsthoselessonsconsideredmostimportanttotheircommunityandtodaytheyofferapowerfullookingglassbywhichtoevaluateandconsiderthecontextualenvironmentinwhichthosecultureexisted.Theauthorappearstoviewfablesas

设A=则A2011-2A2010=______

A=Am×nRA．=rb为m维列向量则有______

Whereverpeoplehavebeentheyhaveleftwastebehindwhichcancauseallsortsofproblems.Wasteoftenstinksattractsverminandcreateseyesores.Moreseriouslyitcanreleaseharmfulchemicalsintothesoilandwaterwhendumpedorintotheairwhenburned.Andthentherearesomereallynastyformsofindustrialwastesuchasspentnuclearfuelforwhichnouniversallyaccepteddisposalmethodshavethusfarbeendeveloped.Yetmanyalsoseewasteasanopportunity.Gettingridofitallhasbecomeahugeglobalbusiness.Richcountriesspendsome$120billionayeardisposingoftheirmunicipalwastealoneandanother$150billiononindustrialwaste.Theamountofwastethatcountriesproducetendstogrowintandemwiththeireconomiesandespeciallywiththerateofurbanization.SowastefirmsseearichfutureinplacessuchasChinaIndiaandBrazilwhichatpresentspendonlyabout$5billionayearcollectingandtreatingtheirmunicipalwaste.Wastealsopresentsanopportunityinagrandersense:asapotentialresource.Muchofitisalreadyburnedtogenerateenergy.Clevernewtechnologiestoturnitintofertiliserorchemicalsorfuelarebeingdevelopedallthetime.Visionariesseeaworldwithoutwastewithrubbishbeingroutinelyrecycled.Untillastsummersuchviewswerespreadingquickly.Butsincethenplummetingpricesforvirginpaperplasticandfuelsandhencealsoforthewastethatsubstitutesforthemhaveputanendtosuchvisions.Manyoftherecyclingfirmsthathadarguedrubbishwasonthewayoutnowsaythatunlesstheyaregivenfinancialhelptheythemselveswilldisappear.Subsidiesareabadidea.Governmentshavearoletoplayinthebusinessofwastemanagementbutitisaregulatoryandsupervisoryone.Theyshouldobligepeoplewhocreatewastetocleanupafterthemselvesandideallyensurethatthepriceofanyproductreflectsthecostofdisposingofitsafely.Thatwouldhelptosignalwhichitemsarehardesttogetridofgivingconsumersanincentivetobuygoodsthatcreatelesswasteinthefirstplace.Thatmaysoundsimpleenoughbutgovernmentsseldomgettherolesright.Inpoorercountriestheyoftenhavenorulesatalloriftheyhavethemtheyfailtoenforcethem.Inrichcountriestheyareofteninconsistent:toostrictaboutsomesortsofwasteandworryinglylaxaboutothers.Theyarealsopronetoimposingarbitrarytargetsandtaxes.Californiaforexamplewantstorecycleallitstrashnotbecauseitnecessarilymakesenvironmentaloreconomicsensebutbecausethegoalofzerowastesoundspoliticallyattractive.Manyrecyclingfirmsaredisappointednowforthereasonthat______.

=______．

Cyberspacedatasuperhighwaysmultimedia—forthosewhohaveseenthefuturethelinkingofcomputerstelevisionandtelephoneswillchangeourlivesforever.Yetforallthetalkofaforthcomingtechnologicalutopialittleattentionhasbeengiventotheimplicationsofthesedevelopmentsforthepoor.AswithallnewhightechnologywhiletheWestconcernsitselfwiththehowthequestionofforwhomisputasideonceagain.Economistsareonlynowrealizingthefullextenttowhichthecommunicationsrevolutionhasaffectedtheworldeconomy.Informationtechnologyallowstheextensionoftradeacrossgeographicalandindustrialboundariesandtransnationalcorporationstakefulladvantageofit.Termsoftradeexchangeandinterestratesandmoneymovementsaremoreimportantthantheproductionofgoods.Theelectroniceconomymadepossiblebyinformationtechnologyallowsthehavestoincreasetheircontrolonglobalmarkets—withdestructiveimpactonthehave-nots.Forthemtheresultisinstability.Developingcountrieswhichrelyontheproductionofasmallrangeofgoodsforexportaremadetofeellikesmallpartsintheinternationaleconomicmachine.Asfuturesaretradedoncomputerscreensdevelopingcountriessimplyhavelessandlesscontroloftheirdestinies.SowhataretheoptionsforregainingcontrolOnealternativeisfordevelopingcountriestobuyinthelatestcomputersandtelecommunicationsthemselves—socalleddevelopmentcommunicationsmodernization.Yetthisleadstolong-termdependencyandperhapspermanentconstraintsondevelopingcountries’economies.CommunicationstechnologyisgenerallyexportedfromtheU.S.EuropeorJapan;thepatentsskillsandabilitytomanufactureremaininthehandsofafewindustrializedcountries.Itisalsoexpensiveandimportedproductsandservicesmustthereforebeboughtoncredit—creditusuallyprovidedbytheverycountrieswhosecompaniesstandtogain.Furthermorewhennewtechnologyisintroducedthereisoftentoolowalevelofexpertisetoexploititfornativedevelopment.Thismeansthatwhilelocalelitesforeigncommunitiesandsubsidiariesoftransnationalcorporationsmaybenefitthosewhoselivesdependonaccesstotheinformationaredeniedit.Thedevelopmentofmodemcommunicationstechnologyindevelopingcountriesmay

In1999thepriceofoilhoveredaround$16abarrel.By2008ithad1the$100abarrelmark.Thereasonsforthesurge2fromthedramaticgrowthoftheeconomiesofChinaandIndiatowidespread3inoil-producingregionsincludingIraqandNigeria’sdeltaregion.Triple-digitoilpriceshave4theeconomicandpoliticalmapoftheworld5someoldnotionsofpower.Oil-richnationsareenjoyinghistoricgainsandopportunities6majorimporters—includingChinaandIndiahometoathirdoftheworldspopulation—7risingeconomicandsocialcosts. Managingthisneworderisfastbecomingacentral8ofglobalpolitics.Countriesthatneedoilareclawingateachotherto9scarcesuppliesandarewillingtodealwithanygovernment10howun-pleasanttodoit. Inmanypoornationswithoiltheprofitsarebeinglosttocorruption11thesecountriesoftheirbesthopefordevelopment.Andoilisfuelingenormousinvestmentfundsrunbyforeigngovernments12someinthewestseeasanewthreat. CountrieslikeRussiaVenezuelaandIranarewellsuppliedwithrisingoil13achangereflectedinnewlyaggressiveforeignpolicies.Butsomeunexpectedcountriesarereapingbenefits14costsfromhigherprices.ConsideringGermany15itimportsvirtuallyallitsoilithasprosperedfromextensivetradewithaboomingRussiaandtheMiddleEast.GermanexportstoRussia16128percentfrom2001to2006. IntheUnitedStatesasalreadyhighgaspricesrose17higherinthespringof2008theissuecroppedupinthepresidentialcampaignwithSenatorsMcCainandObama18forafederalgastaxholidayduringthepeaksummerdrivingmonths.Anddrivinghabitsbeganto19assalesofsmallcarsjumpedandmasstransportsystems20thecountryreportedasharpincreaseinriders 15

设X服从正态分布N022而X1X2X15为来自总体X的简单随机样本则随机变量所服从的分布为______

设函数y=yx由方程组所确定试求．

设二次型的正负惯性指数都是1则a=______

设向量组Ⅰα1α2αs的秩为r1向量组Ⅱβ1β2βs的秩为r2且向量组Ⅱ可由向量组Ⅰ线性表示则______

OneofthemostpressingchallengesthattheUnitedStates—andindeedtheworld—willfaceinthenextfewdecadesishowtoalleviatethegrowingstressthathumanactivitiesareplacingontheenvironment.Theconsequencesarejusttoogreattoignore.Wildlifehabitatsarebeingdegradedordisappearingaltogetherasnewdevelopmentstakeupmoreland.PlantandanimalspeciesarebecomingextinctatagreaterratenowthanatanytimeinEarth’shistory.Asmanyas30percentoftheworld’sfishstocksareoverexploited.Andthelistgoeson.Yetthereisreasontohavehopeforthefuture.Advancesincomputingpowerandmolecularbiologyareamongthetremendousincreasesinscientificcapabilitythatarehelpingresearchersgainabetterunderstandingoftheseproblems.Recentdevelopmentsinscienceandtechnologycouldprovidethebasisforsomemajorandtimelyactionsthatwouldimproveourunderstandingofhowhumanactivitiesaffecttheenvironment.Onepriorityforresearchisimprovinghydrologicalforecasting.Ithasbeenestimatedthattheworld’swaterusecouldtripleinthenexttwodecades.AlreadywidespreadwatershortageshaveoccurredinpartsofChinaIndiaNorthAfricaandtheArabianPeninsula.TheneedforwateralsoistakingitstollonfreshwaterecosystemsintheUnitedStates.Only2percentofthenation’sstreamsareconsideredingoodconditionandcloseto40percentofnativefishspeciesareraretoextinct.Usingavarietyofnewremotesensingtoolsscientistscanlearnmoreabouthowprecipitationaffectswaterlevelshowsurfacewaterisgeneratedandtransportedandhowchangesinthelandscapeaffectwatersupplies.Topreventoutbreaksofinfectiousdiseasesinplantsanimalsandhumansmorestudyisneededonhowpathogensparasitesanddisease-carryingspecies—aswellashumansandotherspeciestheyinfect—areaffectedbychangesintheenvironment.Theoveruseofantibioticsbothinhumansandinfarmanimalshascontributedtothegrowthofantibiotic-resistantmicroorganisms.Researcherscantakeadvantageofnewtechnologiesingeneticsandcomputingtobettermonitorandpredicttheeffectsthatenvironmentalchangesmighthaveondiseaseoutbreaks.HumanshavemadealterationstoEarth’ssurface—suchastropicaldeforestationreductionofsurfaceandgroundwaterandmassivedevelopment—sodramaticthattheyapproachthelevelsoftransformationthatoccurredduringglacialperiods.Suchalterationscausechangesinlocalandregionalclimateandwilldeterminethefutureofagriculture.Recentadvancesindatacollectionandanalysisshouldbeusedtodocumentandbetterunderstandthecausesandconsequencesofchangesinlandcoveranduse.ThepoorconditionofstreamsintheU.S.canbeattributedto

Upuntilafewdecadesagoourvisionsofthefuturewerelargely—thoughbynomeansuniformly—glowinglypositive.Scienceandtechnologywouldcurealltheillsofhumanityleadingtolivesoffulfillmentandopportunityforall.Nowutopiahasgrownunfashionableaswehavegainedadeeperappreciationoftherangeofthreatsfacingusfromasteroidstriketoepidemicflutoclimatechange.Youmightevenbetemptedtoassumethathumanityhaslittlefuturetolookforwardto.Butsuchgloominessismisplaced.Thefossilrecordshowsthatmanyspecieshaveenduredformillionsofyears—sowhyshouldn’tweTakeabroaderlookatourspecies’placeintheuniverseanditbecomesclearthatwehaveanexcellentchanceofsurvivingfortensifnothundredsofthousandsofyears.LookupHomosapiensintheRedListofthreatenedspeciesoftheInternationalUnionfortheConversationofNatureIUCNandyouwillread:ListedasLeastConcernasthespeciesisverywidelydistributedadaptablecurrentlyincreasingandtherearenomajorthreatsresultinginanoverallpopulationdecline.SowhatdoesourdeepfutureholdAgrowingnumberofresearchersandorganizationsarenowthinkingseriouslyaboutthatquestion.ForexampletheLongNowFoundationhasitsflagshipprojectamechanicalclockthatisdesignedtostillbemarkingtimethousandsofyearshence.Perhapswillfullyitmaybeeasiertothinkaboutsuchlengthytimescalesthanaboutthemoreimmediatefuture.Thepotentialevolutionoftoday’stechnologyanditssocialconsequencesisdazzlinglycomplicatedandit’sperhapsbestlefttosciencefictionwritersandfuturologiststoexplorethemanypossibilitieswecanenvisage.That’sonereasonwhywehavelaunchedArcanewpublicationdedicatedtothenearfuture.Buttakealongerviewandthereisasurprisingamountthatwecansaywithconsiderableassurance.Assooftenthepastholdsthekeytothefuture:wehavenowidentifiedenoughofthelong-termpatternsshapingthehistoryoftheplanetandourspeciestomakeevidence-basedforecastsaboutthesituationsinwhichourdescendantswillfindthemselves.Thislongperspectivemakesthepessimisticviewofourprospectsseemmorelikelytobeapassingfad.Tobesurethefutureisnotallrosy.Butwearenowknowledgeableenoughtoreducemanyoftherisksthatthreatenedtheexistenceofearlierhumansandtoimprovethelotofthosetocome.Ourvisionofthefutureusedtobeinspiredby

In1999thepriceofoilhoveredaround$16abarrel.By2008ithad1the$100abarrelmark.Thereasonsforthesurge2fromthedramaticgrowthoftheeconomiesofChinaandIndiatowidespread3inoil-producingregionsincludingIraqandNigeria’sdeltaregion.Triple-digitoilpriceshave4theeconomicandpoliticalmapoftheworld5someoldnotionsofpower.Oil-richnationsareenjoyinghistoricgainsandopportunities6majorimporters—includingChinaandIndiahometoathirdoftheworldspopulation—7risingeconomicandsocialcosts. Managingthisneworderisfastbecomingacentral8ofglobalpolitics.Countriesthatneedoilareclawingateachotherto9scarcesuppliesandarewillingtodealwithanygovernment10howun-pleasanttodoit. Inmanypoornationswithoiltheprofitsarebeinglosttocorruption11thesecountriesoftheirbesthopefordevelopment.Andoilisfuelingenormousinvestmentfundsrunbyforeigngovernments12someinthewestseeasanewthreat. CountrieslikeRussiaVenezuelaandIranarewellsuppliedwithrisingoil13achangereflectedinnewlyaggressiveforeignpolicies.Butsomeunexpectedcountriesarereapingbenefits14costsfromhigherprices.ConsideringGermany15itimportsvirtuallyallitsoilithasprosperedfromextensivetradewithaboomingRussiaandtheMiddleEast.GermanexportstoRussia16128percentfrom2001to2006. IntheUnitedStatesasalreadyhighgaspricesrose17higherinthespringof2008theissuecroppedupinthepresidentialcampaignwithSenatorsMcCainandObama18forafederalgastaxholidayduringthepeaksummerdrivingmonths.Anddrivinghabitsbeganto19assalesofsmallcarsjumpedandmasstransportsystems20thecountryreportedasharpincreaseinriders 19

设fx在-∞+∞内是可导的奇函数则下列函数中是奇函数的是______

Collegegraduatesarenowleavingschoolwithnotonlyadiplomabutalsowithmoredebtthaninanyotherperiodinhistory.AccordingtotheCollegeBoardaveragefinancialaidperfulltimeequivalentstudentadjustedforinflationhasalmostdoubledinthelastdecade.Additionallynotonlyistheaveragestudentdebtloadhigherbutalsothenumberofloansoriginatedincreasedbynearlyfourfold.Thusstudentlendinghasincreasedinbreadthaswellasdepthdoublyimpactingthefinancialsituationsofthosestudentswhomustdependonstudentloanstofinancetheireducation.Furthermorethesefiguresnodoubtunderstatethetruelevelofindebtednessincurredbystudentsandtheirfamiliessincesomeundoubtedlyfinancepartoftheireducationandlivingexpensesthroughtheuseofconsumerloanshomeequityloansorcreditcards.Thusthealreadyhugeburdenofstudentloandebtincurredbystudentsandtheirfamiliesisexacerbatedbyfinancialobligationsfromothersources.Thissituationistheoutcomeofaprecariouscombinationofeasycreditthankstocardissuerswhoareeagertotapintothislucrativemarketfinancialnaivetéonthepartofstudentsandasenseonbothsidesthatifworsecomestoworsemommyanddaddywillstepinandsetthingsright.Allcombinetomakecreditatemptingluretostudentsstrappedforcash.Whilecreditstillremainavirtualelementforthefinancingofmanystudents’educationatexpensivecollegesitsimplicationsmustcarefullyweighedandconsideredlestthecash-poorstudentfindhimselfwithmorethathebargainedfor.MoststudentsintheUnitedStatesattendcollegeswhosetuitiondoesnotexceed$15000however.Neverthelessrisingpricescombinedwithstagnantincomegainsamonglow-andmoderate-incomefamilieshavemadeitdifficultifnotimpossibleforastudentfromafamilyofsuchanincomelevelastudentwhohasthemosttogainfromacollegeeducationtoattendcollegewithoutsignificantlyaddingtothefinancialburdenofhisorherfamily.Whilestudentloansstillremainavitalelementforthefinancingofmanystudents’educationatexpensivecollegesitsimplicationsmustbecarefullyweighedandconsideredlestthecash-poorstudentfindhimselfwithmorethanhebargainedfor.Theauthorviewsstudentloansas

=______

设n阶实对称矩阵A的秩为r且满足A2=A求Ⅰ二次型xTAx的标准形Ⅱ行列式|E+A+A2++An|的值其中E为单位矩阵

A.Internationalstudentshavethesameneedsaslocalstudentsandshouldbeaccordedequivalentrightsandprotections—exceptinafewareassuchasvotinginnationalelections.Amorecomprehensiveandrights-basedapproachtothesecurityofinternationalstudentscouldbeobtainedthroughbilateralnegotiationsbetweenthecountriesthatsendandreceivethem.ChinaIndiaMalaysiaandothernationsshouldseekasystematicregimeofprotectionandrespectfortheircitizenswhostudyinothercountries.Asapatternofbilateralnegotiationsbecameestablishedcommonglobalstandardscouldemerge.B.WhatdidwefindTheexperienceofinternationalstudentsdiffersfromthatoflocalstudentsinthreeways.Firstthelivesofinternationalstudentsaremoremarginallonelierandlessinformedthanthoseoftheirlocalpeers.SecondthemajorityofinternationalstudentsinAustraliafaceatleastsomebarrierstocommunicatinginEnglishthataffectnotjustacademicprogressbutalsodailylife.Problemsofabuseordiscriminationareoftenassociatedwithcommunicationsissues.Thirdtherearepronounceddifferencesbetweenlocalandinternationalstudentsinareaswhereculturalidentityareatplaynotjustincross-culturalrelationsbutinlookingforrentalhousingseekingajobandsoon.C.Nationalandstategovernmentsshouldalsosubsidizeaffordablehousingforamixofinternationalandlocalstudentsinareaswherestudentsstudyandwork.Thegovernmentsshouldalsorequireinspectionsofstudents’rentalhousing.Theyshouldprovidesupervisedtransportespeciallyatnight.Thepoliceshouldpatrolhotspotswhereviolenceisoccurringormightoccur.Internationalstudentsshouldreceiveadequateinformationaboutsafetyandsecurityuponarrivalintheirnewcountries.D.Wedefinedstudentsecurityasincludingthefullrangeofissuesaffectingtheempowermentandprotectionofinternationalstudents:financialsupporthousinghealthsafetyworkissuesandrelationswiththeiruniversitiesandthegovernment’simmigrationdepartment.Wealsolookedintointernationalstudents’personalnetworkscommunicationsandinterculturalissues.WeconductedtheempiricalworkforourstudyinAustraliabutourresearchandthatofotherscholarsshowthattheunderlyingissuesarecommontosomeextenttoallcountries.E.Thefundamentalproblemhoweverlieswithnations’regulatoryframeworkswhichshouldbemodifiedforaglobalizedworld.Wemustfindwaysofmovinginternational-studentsecurityupthepolicyagendaofnationalgovernmentsmultilateralforumsandglobalagencies.AustralianinternationaleducationforexampleisnowregulatedthroughtheEducationServicesforOverseasStudentsAct.Itimposesobligationsonproviderinstitutionsmostlyinrelationtoconsumerprotectionandimmigrationcompliance.Butsafetyoncampusisnotmentioned.Theactdoesnotcoverstudents’livesinthecommunityoutsidethecampuswheremostproblemsofsecurityoccur.F.Butdelvedeeperandyouwillfindthatalthoughmoststudentssucceedabroadandhavesatisfyingexperiencescertainlynotallofthemdo—andsomehavemajorproblemswhichcanrangefarbeyondlonelinessanddifficultiesadjustingtonewcultures.Someinternationalstudentsarevictimsofterriblecrimes.Unfortunatelytheirsecurityisnotadequatelyensuredbythecountrieswheretheystudywhichstilltreatthemasoutsidersandtheirrightsasprivilegesthatcanbeignored.Eventhoughglobalmobilityineducationhasrenderedsuchanapproachobsoletenationalregulationshavenotkeptpace.G.WhatshouldbedonetoimprovethesafetyandsecurityofinternationalstudentsForthemsecuritymeansnotonlyprotectionbutalsothecapacitytooperateasfreehumanagentsmakingchoices.Formanyinternationalstudentsacquiringcommunicationskillsisalmostasimportantasacquiringdegrees.UniversitiesinEnglish-speakingcountriesshouldmakeEnglish-languagecommunicationaformalrequirementfordegreestatus.

设ab为正常系数λ为非负常数微分方程Ⅰ求该方程的通解Ⅱ证明当λ=0时当λ＞0时

设且F可微证明

电话公司有300台分机每台分机有6%的时间处于与外线通话状态设每台分机是否处于通话状态相互独立用中心极限定理估计至少安装多少条外线才能保证每台分机使用外线不必等候的概率不低于0.95

积分的值等于______

In1999thepriceofoilhoveredaround$16abarrel.By2008ithad1the$100abarrelmark.Thereasonsforthesurge2fromthedramaticgrowthoftheeconomiesofChinaandIndiatowidespread3inoil-producingregionsincludingIraqandNigeria’sdeltaregion.Triple-digitoilpriceshave4theeconomicandpoliticalmapoftheworld5someoldnotionsofpower.Oil-richnationsareenjoyinghistoricgainsandopportunities6majorimporters—includingChinaandIndiahometoathirdoftheworldspopulation—7risingeconomicandsocialcosts. Managingthisneworderisfastbecomingacentral8ofglobalpolitics.Countriesthatneedoilareclawingateachotherto9scarcesuppliesandarewillingtodealwithanygovernment10howun-pleasanttodoit. Inmanypoornationswithoiltheprofitsarebeinglosttocorruption11thesecountriesoftheirbesthopefordevelopment.Andoilisfuelingenormousinvestmentfundsrunbyforeigngovernments12someinthewestseeasanewthreat. CountrieslikeRussiaVenezuelaandIranarewellsuppliedwithrisingoil13achangereflectedinnewlyaggressiveforeignpolicies.Butsomeunexpectedcountriesarereapingbenefits14costsfromhigherprices.ConsideringGermany15itimportsvirtuallyallitsoilithasprosperedfromextensivetradewithaboomingRussiaandtheMiddleEast.GermanexportstoRussia16128percentfrom2001to2006. IntheUnitedStatesasalreadyhighgaspricesrose17higherinthespringof2008theissuecroppedupinthepresidentialcampaignwithSenatorsMcCainandObama18forafederalgastaxholidayduringthepeaksummerdrivingmonths.Anddrivinghabitsbeganto19assalesofsmallcarsjumpedandmasstransportsystems20thecountryreportedasharpincreaseinriders 1

______.

设fx在-∞+∞存在二阶导数且fx=-f-x当x＜0时有f’x＜0fx＞0则当x＞0时有______

Relativitytheoryhashadaprofoundinfluenceonourpictureofmatterbyforcingustomodifyourconceptofaparticleinanessentialway.46Inclassicalphysicsthemassofanobjecthadalwaysbeenassociatedwithanindestructiblematerialsubstancewithsomestuffofwhichallthingswerethoughttobemade.Relativitytheoryshowedthatmasshasnothingtodowithanysubstancebutisaformenergy.Energyhoweverisadynamicquantityassociatedwithactivityorwithprocesses.47Thefactthatthemassofaparticleisequivalenttoacertainofenergymeansthattheparticlecannolongerbeseenasastatic_objectbuthastobeconceivedasadynamicpatternaprocessinvolvingtheenergywhichmanifestitselfastheparticle’smass.48ThisnewviewofparticleswasinitiatedbyDiracwhenheformulatedarelativisticequationdescribingthebehaviorofelectrons.Dirac’stheorywasnotonlyextremelysuccessfulinaccountingforthefinedetailsofatomicstructurebutalsorevealedafundamentalsymmetrybetweenmatterandanti-matter.Itpredictedtheexistenceofananti-matterwiththesamemassastheelectronbutwithanoppositecharge.ThispositivelychargedparticlenowcalledthepositronwasindeeddiscoveredtwoyearsafterDirachadpredictedit.Thesymmetrybetweenmatterandanti-matterimpliesthatforeveryparticlethereexistsanantiparticleswithequalmassandoppositecharge.Pairsofparticlesandantiparticlescanbecreatedifenoughenergyisavailableandcanbemadetoturnintopureenergyinthereverseprocessofdestruction.49TheseprocessesofparticlecreationanddestructionhadbeenpredictedfromDirac’stheorybeforetheywereactuallydiscoveredinnatureandsincethentheyhavebeenobservedmillionsoftimes.Thecreationofmaterialparticlesfrompureenergyiscertainlythemostspectaculareffectofrelativitytheoryanditcanonlybeunderstoodintermsoftheviewofparticlesoutlinedabove.50Beforerelativisticparticlephysicstheconstituentsofmatterhadalwaysbeenconsideredasbeingeitherelementaryunitswhichwereindestructibleandunchangeableorascompositeobjectswhichcouldbebrokenupintotheirconstituentparts.Andthebasicquestionwaswhetheronecoulddividematteragainandagainorwhetheronewouldfinallyarriveatsomesmallestindivisibleunits.

=______

dxdx=______

Chronicinsomniaisamajorpublichealthproblem.Andtoomanypeopleareusing1therapiesevenwhilethereareafewtreatmentsthatdowork.MillionsofAmericans2awakeatnightcountingsheeporhaveastiffdrinkor3anpillhopingitwillmakethemsleepy.4expertsagreeallthatself-medicatingisabadideaandthecausesofchronicinsomniaremain5. Almostathirdofadultshavetroublesleepingandabout10percenthave6ofdaytimeimpairmentthatsignaltrueinsomnia.But7thecomplaintsscientistsknowsurprisinglylittleaboutwhatcauseschronicinsomniaitshealthconsequencesandhowbesttotreatitapanelofspecialists8togetherbytheNationalInstitutesofHealthconcludedWednesday.Thepanelcalled9abroadrangeofresearchintoinsomnia10thatifscientistsunderstoodits11causestheycoulddevelopbettertreatments. Mostbutnotallinsomniaisthoughtto12otherhealthproblemsfromarthritisanddepressiontocardiovasculardisease.Thequestionofteniswhethertheinsomniacamefirstorwasaresultoftheotherdiseasesandhowtroublesleepingin13complicatesthoseotherproblems.Otherdiseases14theriskofinsomniaseemstoincreasewithageandtobemore15amongwomenespeciallyaftertheir50s.Smokingcaffeineandnumerous16drugsalsoaffectsleep. TheNIHisspendingabout$200millionthisyearonsleep-relatedresearchsome17tospecificdisordersandothers18theunderlyingscientificlawsthatcontrolthenervoussystemofsleep.Theagencywas19thepane’sreviewbeforedecidingwhatadditionalworkshouldbe20atinsomnia. 1

当x→0时fx=x-sinax与gx=x2ln1-bx是等价无穷小则______

已知在-∞+∞上存在原函数求常数A并求fx的原函数

Todaysome30%ofsmallbusinessownersdon’thaveaWebpresenceatallwhilethevastmajoritywhodoarewatchingtheirsitessitstalewaitingandwantingforbusiness.WheredidthingsgowrongTherearecommonprinciplesfollowedbythosewhosedreamsofonlinesuccesshavebecomereality.41Buildyoursitearoundyourcustomer:Thinkingofyoursiteasyouronlinestorefrontbuiltarounddeliveringthehighest-qualitycustomerexperiencefromthemomentyourcustomerstepsthroughthedoor.42Justbecauseyoubuiltitdoesn’tmeanthey’llcome:Ifyouaren’tseeingalargevolumeoftargetedtraffictoyoursiteit’stimetouptheante.43Integratecustomerloyaltyprogramsandpromotions:Methodscontaindiscountsnewsorfriendlyservicereminders.Usediscountpromotionalofferstostayintouchwithpastvisitorstoyoursite.44Justifyyourmonthlyspendingthroughproductbundling:Whilepay-per-clickInternetadvertisingismuchmorecost-effectivethantraditionalmediachannelsbundlingproductstogetherwillnotonlyincreaseyoursalesrevenuebutalsoenableyoutogetmoreoutofyourper-clickadrates.45Measureyourprogress:YoursitemaybelivebuthowisitperformingArmedwiththesesimplelessonsvowtomakeyourbusinessrealizethetruepromiseoftheInternet.A.Amanufacturingcompanyselling$50itemswashavingtroublejustifyingthecostofonlinekeywordads.Bybundlingproductstocreatepackagesof$100ormoreandadvertisingtowholesalecustomerslookingtobuyinbulkthemanufacturerdroppeditssalesrepresentativeagenciesandfocusedonlargevolumebuyerssuchasWal-MartandTarget.Needlesstosaythecompanyhadnotroubleexceedingitsyearlysalesquota.B.Oneofmypastclientshadawell-designedphysicalstorefrontsolidpricesandqualityofferings.Howeverhewasn’tabletodriveenoughstoretrafficdespitetargetedadvertisingeffortsinprintpublicationsandotherofflinevenues.Wedecidedtoshiftthoseaddollarstoanonlinepay-per-clickcampaign—inwhichtheadvertiserpayswheneversomeoneclicksonitsentrypostedduringthecourseofasitesearchbasedonkeywordsrelevanttohisbusiness.Theimmediateimpactwasstaggering.Onlinerevenuesoaredtenfoldto$1millionfrom$100000withinonlyafewmonths.C.Withtoday’stechnologyyourreturncanbeeasilymeasured.IfyourelyonyourWebsiteasasalestoolyoucan’taffordnottoinvestinsiteanalytics.MakesureyourWebsolutionincludesaneasy-to-usereportingtoolthatpresentsthisinformationinaclearconciseformat.AfterallwhilemetricsareacriticalpartoftheWebequationyoudon’thavethetimetospendhoursdiggingthroughreamsofdata.D.YearsagoIworkedwithawomanwhosoldpursesonlinethroughahome-builtsitethatlackedcriticale-commercecomponents.Afterasimpleredesignincludingproductdescriptionscomprehensivenavigationandasecureuser-friendlyorderingsystemherrevenueincreasedfivefold.Andshebeganreceivingravereviewsfromcustomersimpressedwiththeeaseandconvenienceoftheonlineshoppingexperience.E.Onlinesuccessdemandsmorethansimplepresence.YourInternetinvestmentshouldpayforitselfwithnewcustomersandincreasedsales.Findatrustedpartnerwhocanhelpyounavigatetoday’sandtomorrow’stechnologyandwhounderstandsthebottom-linerealitiesofyourbusiness.F.OnevillarentalcompanyhadaWebsitethatgeneratedveryfewcallsandonlinebookings.Ihelpedthecompanysetupalastminutedealsdistributionlist.Bysubscribingsitevisitorswouldreceiveweeklye-mailsoffering11th-hourdiscountsonvillarentals.Asaresultthecompanycapturedcontactinformationforthousandsofpossiblecustomersreduceditsunusedinventorytoalmostzeroandincreasedrevenuesignificantly.

Todaysome30%ofsmallbusinessownersdon’thaveaWebpresenceatallwhilethevastmajoritywhodoarewatchingtheirsitessitstalewaitingandwantingforbusiness.WheredidthingsgowrongTherearecommonprinciplesfollowedbythosewhosedreamsofonlinesuccesshavebecomereality.41Buildyoursitearoundyourcustomer:Thinkingofyoursiteasyouronlinestorefrontbuiltarounddeliveringthehighest-qualitycustomerexperiencefromthemomentyourcustomerstepsthroughthedoor.42Justbecauseyoubuiltitdoesn’tmeanthey’llcome:Ifyouaren’tseeingalargevolumeoftargetedtraffictoyoursiteit’stimetouptheante.43Integratecustomerloyaltyprogramsandpromotions:Methodscontaindiscountsnewsorfriendlyservicereminders.Usediscountpromotionalofferstostayintouchwithpastvisitorstoyoursite.44Justifyyourmonthlyspendingthroughproductbundling:Whilepay-per-clickInternetadvertisingismuchmorecost-effectivethantraditionalmediachannelsbundlingproductstogetherwillnotonlyincreaseyoursalesrevenuebutalsoenableyoutogetmoreoutofyourper-clickadrates.45Measureyourprogress:YoursitemaybelivebuthowisitperformingArmedwiththesesimplelessonsvowtomakeyourbusinessrealizethetruepromiseoftheInternet.A.Amanufacturingcompanyselling$50itemswashavingtroublejustifyingthecostofonlinekeywordads.Bybundlingproductstocreatepackagesof$100ormoreandadvertisingtowholesalecustomerslookingtobuyinbulkthemanufacturerdroppeditssalesrepresentativeagenciesandfocusedonlargevolumebuyerssuchasWal-MartandTarget.Needlesstosaythecompanyhadnotroubleexceedingitsyearlysalesquota.B.Oneofmypastclientshadawell-designedphysicalstorefrontsolidpricesandqualityofferings.Howeverhewasn’tabletodriveenoughstoretrafficdespitetargetedadvertisingeffortsinprintpublicationsandotherofflinevenues.Wedecidedtoshiftthoseaddollarstoanonlinepay-per-clickcampaign—inwhichtheadvertiserpayswheneversomeoneclicksonitsentrypostedduringthecourseofasitesearchbasedonkeywordsrelevanttohisbusiness.Theimmediateimpactwasstaggering.Onlinerevenuesoaredtenfoldto$1millionfrom$100000withinonlyafewmonths.C.Withtoday’stechnologyyourreturncanbeeasilymeasured.IfyourelyonyourWebsiteasasalestoolyoucan’taffordnottoinvestinsiteanalytics.MakesureyourWebsolutionincludesaneasy-to-usereportingtoolthatpresentsthisinformationinaclearconciseformat.AfterallwhilemetricsareacriticalpartoftheWebequationyoudon’thavethetimetospendhoursdiggingthroughreamsofdata.D.YearsagoIworkedwithawomanwhosoldpursesonlinethroughahome-builtsitethatlackedcriticale-commercecomponents.Afterasimpleredesignincludingproductdescriptionscomprehensivenavigationandasecureuser-friendlyorderingsystemherrevenueincreasedfivefold.Andshebeganreceivingravereviewsfromcustomersimpressedwiththeeaseandconvenienceoftheonlineshoppingexperience.E.Onlinesuccessdemandsmorethansimplepresence.YourInternetinvestmentshouldpayforitselfwithnewcustomersandincreasedsales.Findatrustedpartnerwhocanhelpyounavigatetoday’sandtomorrow’stechnologyandwhounderstandsthebottom-linerealitiesofyourbusiness.F.OnevillarentalcompanyhadaWebsitethatgeneratedveryfewcallsandonlinebookings.Ihelpedthecompanysetupalastminutedealsdistributionlist.Bysubscribingsitevisitorswouldreceiveweeklye-mailsoffering11th-hourdiscountsonvillarentals.Asaresultthecompanycapturedcontactinformationforthousandsofpossiblecustomersreduceditsunusedinventorytoalmostzeroandincreasedrevenuesignificantly.

如果

Themythologyofaculturecanprovidesomevitalinsightsintothebeliefsandvaluesofthatculture.Byusingfantasticandsometimesincrediblestoriestocreateanoraltraditionbywhichtoexplainthewondersofthenaturalworldandteachlessonstoyoungergenerationsasocietyexposesthoseideasandconceptsheldmostimportant.Justasimportantasthefinallessontobegatheredfromthestorieshoweverarethecharactersandtherolestheyplayinconveyingthatmessage.PerhapstheepitomeofmythologyanditsuseasatooltopassonculturalvaluescanbefoundinAesop’sFablestoldandretoldduringtheeraoftheGreekEmpire.Aesopaslavewhowonthefavorofthecourtthroughhisimaginativeanddescriptivetalesalmostexclusivelyusedanimalstofilltherolesinhisshortstories.Humanswhenatallpresentalmostalwaysplayedthepartofbumblingfoolsstrugglingtolearnthelessonbeingpresented.ThischoiceofcharacterizationallowsustoseethattheGreeksplacedwisdomonalevelslightlybeyondhumansimplyingthatdeepwisdomandunderstandingisauniversalqualitysoughtbyratherthansteanningfromhumanbeings.Aesop’sfablesillustratedthecentralthemesofhumilityandself-reliancereflectingtheimportanceofthosetraitsinearlyGreeksociety.Thefollyofhumanswasusedtocontrastagainsttheultimategoalofattainingahigherlevelofunderstandingandawarenessoftruthsaboutnatureandhumanity.Forexampleonenotablefablefeaturesafoxrepeatedlytryingtoreachabunchofgrapesonaveryhighvine.Afterfailingatseveralattemptsthefoxgivesupmakingupitsmindthatthegrapeswereprobablysouranyway.Thefable’slessonthatweoftenplaydownthatwhichwecan’tachievesoastomakeourselvesfeelbetterteachesthereaderorlistenerinanentertainingwayaboutoneoftheweaknessesofthehumanpsyche.ThemythologyofotherculturesandsocietiesrevealtheunderlyingtraitsoftheirrespectiveculturesjustasAesop’sfablesdid.ThestoriesofRomangodsAztecghostsandEuropeanelvesallservedtotrainancientgenerationsthoselessonsconsideredmostimportanttotheircommunityandtodaytheyofferapowerfullookingglassbywhichtoevaluateandconsiderthecontextualenvironmentinwhichthosecultureexisted.Themainpointofthistextis

若函数fx与gx在-∞+∞内可导且fx＜gx则必有______

Cyberspacedatasuperhighwaysmultimedia—forthosewhohaveseenthefuturethelinkingofcomputerstelevisionandtelephoneswillchangeourlivesforever.Yetforallthetalkofaforthcomingtechnologicalutopialittleattentionhasbeengiventotheimplicationsofthesedevelopmentsforthepoor.AswithallnewhightechnologywhiletheWestconcernsitselfwiththehowthequestionofforwhomisputasideonceagain.Economistsareonlynowrealizingthefullextenttowhichthecommunicationsrevolutionhasaffectedtheworldeconomy.Informationtechnologyallowstheextensionoftradeacrossgeographicalandindustrialboundariesandtransnationalcorporationstakefulladvantageofit.Termsoftradeexchangeandinterestratesandmoneymovementsaremoreimportantthantheproductionofgoods.Theelectroniceconomymadepossiblebyinformationtechnologyallowsthehavestoincreasetheircontrolonglobalmarkets—withdestructiveimpactonthehave-nots.Forthemtheresultisinstability.Developingcountrieswhichrelyontheproductionofasmallrangeofgoodsforexportaremadetofeellikesmallpartsintheinternationaleconomicmachine.Asfuturesaretradedoncomputerscreensdevelopingcountriessimplyhavelessandlesscontroloftheirdestinies.SowhataretheoptionsforregainingcontrolOnealternativeisfordevelopingcountriestobuyinthelatestcomputersandtelecommunicationsthemselves—socalleddevelopmentcommunicationsmodernization.Yetthisleadstolong-termdependencyandperhapspermanentconstraintsondevelopingcountries’economies.CommunicationstechnologyisgenerallyexportedfromtheU.S.EuropeorJapan;thepatentsskillsandabilitytomanufactureremaininthehandsofafewindustrializedcountries.Itisalsoexpensiveandimportedproductsandservicesmustthereforebeboughtoncredit—creditusuallyprovidedbytheverycountrieswhosecompaniesstandtogain.Furthermorewhennewtechnologyisintroducedthereisoftentoolowalevelofexpertisetoexploititfornativedevelopment.Thismeansthatwhilelocalelitesforeigncommunitiesandsubsidiariesoftransnationalcorporationsmaybenefitthosewhoselivesdependonaccesstotheinformationaredeniedit.Itcanbeinferredfromthepassagethat

设常数λ＞0且级数收敛则级数______

计算二重积分其中积分区域D由y轴与曲线y=y=围成

Collegegraduatesarenowleavingschoolwithnotonlyadiplomabutalsowithmoredebtthaninanyotherperiodinhistory.AccordingtotheCollegeBoardaveragefinancialaidperfulltimeequivalentstudentadjustedforinflationhasalmostdoubledinthelastdecade.Additionallynotonlyistheaveragestudentdebtloadhigherbutalsothenumberofloansoriginatedincreasedbynearlyfourfold.Thusstudentlendinghasincreasedinbreadthaswellasdepthdoublyimpactingthefinancialsituationsofthosestudentswhomustdependonstudentloanstofinancetheireducation.Furthermorethesefiguresnodoubtunderstatethetruelevelofindebtednessincurredbystudentsandtheirfamiliessincesomeundoubtedlyfinancepartoftheireducationandlivingexpensesthroughtheuseofconsumerloanshomeequityloansorcreditcards.Thusthealreadyhugeburdenofstudentloandebtincurredbystudentsandtheirfamiliesisexacerbatedbyfinancialobligationsfromothersources.Thissituationistheoutcomeofaprecariouscombinationofeasycreditthankstocardissuerswhoareeagertotapintothislucrativemarketfinancialnaivetéonthepartofstudentsandasenseonbothsidesthatifworsecomestoworsemommyanddaddywillstepinandsetthingsright.Allcombinetomakecreditatemptingluretostudentsstrappedforcash.Whilecreditstillremainavirtualelementforthefinancingofmanystudents’educationatexpensivecollegesitsimplicationsmustcarefullyweighedandconsideredlestthecash-poorstudentfindhimselfwithmorethathebargainedfor.MoststudentsintheUnitedStatesattendcollegeswhosetuitiondoesnotexceed$15000however.Neverthelessrisingpricescombinedwithstagnantincomegainsamonglow-andmoderate-incomefamilieshavemadeitdifficultifnotimpossibleforastudentfromafamilyofsuchanincomelevelastudentwhohasthemosttogainfromacollegeeducationtoattendcollegewithoutsignificantlyaddingtothefinancialburdenofhisorherfamily.Whilestudentloansstillremainavitalelementforthefinancingofmanystudents’educationatexpensivecollegesitsimplicationsmustbecarefullyweighedandconsideredlestthecash-poorstudentfindhimselfwithmorethanhebargainedfor.ThemainpointofParagraph4is

假设生产和销售某产品的收益R是产量的q二次函数经统计得知当产量q分别为024时总收入R分别为068万元试确定R与q之间的函数关系

幂级数的和函数为______

TheTreasurycouldpocket20millionayearinextrafinesoncethecountry’sspeedcameranetworkisexpanded.Motoringorganizationswarnedthatthe1couldbecomeapolltaxonwheels2hugenumberofdrivers.Therecouldbemanymoreincidentsofvandalism3cameras.Thewarningscame4aDailyMailsurveyfoundalmostallthe23policeforcesinEnglandandWaleswereeither5toexpansionplansorconsidering6. Nationwidethenumberofspeedingticketsisexpectedtotreble790millionayear.8theschemepolicekeepsomeofthecashfromfinesto9thecostsoffittingandmaintainingextracamerasand10thatexistingonesalwayshavefilminthem.TherestwillgototheTreasury.BothMinistersandpoliceinsisttheschemeisaimed11atmakingroadssafer.Theypointtotrialsineightareaswhichcutcollisionsbyaquarteranddeathsandseriousinjuriesby12ahalf. Butmotoringorganizationsfearcameraswillbesitedonrelativelysafe13faststretchestocatchasmanydriversaspossible.Someforcesarealsoexpectedto14thethresholdspeedsatwhichcamerasare15totheabsolutelegalminimum-15mphina10mphlimitand26mphina20mphzone.Thiscouldencouragedriverstostareattheirspeedometersinsteadofconcentratingontheroadand16tomoreaccidents.SueNicholsonheadofcampaignsattheRACsaidWedon’thaveaproblemwithspeedcameras17.Butwedohaveconcernsabout18theyaresited.Policerisklosingcredibility19motoristsifcamerasareseenasrevenue-raising20safetydevices./ 17

Sustainabledevelopmentisappliedtojustabouteverythingfromenergytocleanwaterandeconomicgrowthandasaresultithasbecomedifficulttoquestioneitherthebasicassumptionsbehinditorthewaytheconceptisputtouse.Thisisespeciallytrueinagriculturewheresustainabledevelopmentisoftentakenasthesolemeasureofprogresswithoutaproperappreciationofhistoricalandculturalperspectives.Tostartwithitisimportanttorememberthatthenatureofagriculturehaschangedmarkedlythroughouthistoryandwillcontinuetodoso.MedievalagricultureinnorthernEuropefedclothedandshelteredapredominantlyruralsocietywithamuchlowerpopulationdensitythanitistoday.Ithadminimaleffectonbiodiversityandanypollutionitcausedwastypicallylocalized.Intermsofenergyuseandthenutrientscapturedintheproductitwasrelativelyinefficient.Contrastthiswithfarmingsincethestartoftheindustrialrevolution.Competitionfromoverseasledfarmerstospecializeandincreaseyields.Throughoutthisperiodfoodbecamecheapersafeandmorereliable.Howeverthesechangeshavealsoledtohabitatlossandtodiminishingbiodiversity.What’smoredemandforanimalproductsindevelopingcountriesisgrowingsofastthatmeetingitwillrequireanextra300milliontonsofgrainayearby2050.Yetthegrowthofcitiesandindustryisreducingtheamountofwateravailableforagricultureinmanyregions.Allthismeansthatagricultureinthe21stcenturywillhavetobeverydifferentfromhowitwasinthe20th.Thiswillrequireradicalthinking.Forexampleweneedtomoveawayfromtheideathattraditionalpracticesareinevitablymoresustainablethannewones.Wealsoneedtoabandonthenotionthatagriculturecanbezeroimpact.Thekeywillbetoabandontherathersimpleandstaticmeasuresofsustainabilitywhichcentreontheneedtomaintainproductionwithoutincreasingdamage.Insteadweneedamoredynamicinterpretationonethatlooksattheprosandconsofallthevariouswaylandisused.Therearemanydifferentwaystomeasureagriculturalperformancebesidesfoodyield:energyuseenvironmentalcostswaterpuritycarbonfootprintandbiodiversity.ItisclearforexamplethatthecarbonoftransportingtomatoesfromSpaintotheUKislessthanthatofproducingthemintheUKwithadditionalheatingandlighting.Butwedonotknowwhetherlowercarbonfootprintswillalwaysbebetterforbiodiversity.Whatiscrucialisrecognizingthatsustainableagricultureisnotjustaboutsustainablefoodproduction.Specializationandtheefforttoincreaseyieldshaveresultedin

设λ1λ2是n阶矩阵A的特征值α1α2分别是A的属于λ1λ2的特征向量则______

Inapurelybiologicalsensefearbeginswiththebody’ssystemforreactingtothingsthatcanharmus—theso-calledfight-or-flightresponse.Ananimalthatcan’tdetectdangercan’tstayalivesaysJosephLeDoux.Likeanimalshumansevolvedwithanelaboratemechanismforprocessinginformationaboutpotentialthreats.Atitscoreisaclusterofneuronsdeepinthebrainknownastheamygdala. LeDouxstudiesthewayanimalsandhumansrespondtothreatstounderstandhowweformmemoriesofsignificanteventsinourlives.Theamygdalareceivesinputfrommanypartsofthebrainincludingregionsresponsibleforretrievingmemories.Usingthisinformationtheamygdalaappraisesasituation—Ithinkthischargingdogwantstobiteme—andtriggersaresponsebyradiatingnervesignalsthroughoutthebody.Thesesignalsproducethefamiliarsignsofdistress:tremblingperspirationandfast-movingfeetjusttonamethree. Thisfearmechanismiscriticaltothesurvivalofallanimalsbutnoonecansayforsurewhetherbeastsotherthanhumansknowthey’reafraid.ThatisasLeDouxsaysifyouputthatsystemintoabrainthathasconsciousnessthenyougetthefeelingoffear. HumanssaysEdwardM.Hallowellhavetheabilitytocallupimagesofbadthingsthathappenedinthepastandtoanticipatefutureevents.Combinethesehigherthoughtprocesseswithourhardwireddangerdetectionsystemsandyougetanear-universalhumanphenomenon:worry. That’snotnecessarilyabadthingsaysHallowell.Whenusedproperlyworryisanincredibledevicehesays.Afterallalittlehealthyworryingisokayifitleadstoconstructiveaction—likehavingadoctorlookatthatweirdspotonyourback. Hallowellinsiststhoughthatthere’sarightwaytoworry.Neverdoitalonegetthefactsandthenmakeaplan.Hesays.Mostofushavesurvivedarecessionsowe’refamiliarwiththebelt-tighteningstrategiesneededtosurviveaslump. Unfortunatelyfewofushavemuchexperiencedealingwiththethreatofterrorismsoit’sbeendifficulttogetfactabouthowweshouldrespond.That’swhyHallowellbelievesitwasokayforpeopletoindulgesomeextremeworrieslastfallbyaskingdoctorsforCiproandbuyinggasmasks. WhichofthefollowingisthebestwaytodealWithyourworriesaccordingtoHallowell

设幂级数的收敛半径为2则级数a+1n的收敛区间为______

设函数fx连续则=______

TheissueofonlineprivacyintheInternetagefoundnewurgencyfollowingtheSept.11terroristattackssparkingdebateoverstrikingthecorrectbalancebetweenprotectingcivillibertiesandattemptingtopreventanothertragicterroristact.Whilepreventingterrorismcertainlyisofparamountimportanceprivacyrightsshouldnotbedeemedirrelevant.InresponsetotheattacksCongressquicklypassedlegislationthatincludedprovisionsexpandingrightsofinvestigatorstointerceptwireoralandelectroniccommunicationsofallegedhackersandterrorists.CivillibertiesgroupsexpressedconcernsovertheprovisionsandurgedcautioninensuringthateffortstoprotectournationdonotresultinbroadgovernmentauthoritytoerodeprivacyrightsofU.S.citizens.NeverthelesscausingfurtherconcerntocivillibertiesgroupstheDepartmentofJusticeproposedexceptionstotheattorney-clientprivilege.OnOct.30AttorneyGeneralJohnAshcroftapprovedaninterimagencyrulethatwouldpermitfederalprisonauthoritiestomonitorwireandelectroniccommunicationsbetweenlawyersandtheirclientsinfederalcustodyincludingthosewhohavebeendetainedbutnotchargedwithanycrimewheneversurveillanceisdeemednecessarytopreventviolenceorterrorism.Inlightofthisbroadeningefforttoreachintocommunicationsthatwerepreviouslybelievedtobeoff-limitstheissueofonlineprivacyisnowanevenmorepressingconcern.CongresshastakensomelegislativestepstowardensuringonlineprivacyincludingtheChildren’sOnlinePrivacyProtectionActandprovidedprivacyprotectionsforcertainsectorsthroughlegislationsuchastheFinancialServicesModernizationAct.Thelegislationpassedtodatedoesnothoweverprovideastatutoryschemeforprotectinggeneralonlineconsumerprivacy.Lackingdefinitivefederallawsomestatespassedtheirownmeasures.Butmuchofthislegislationisincompleteornotenforced.Moreoveritbecomesunworkablewhenstatescreatedifferentprivacystandards;theInternetdoesnotknowgeographicboundariesandcompaniesandindividualscannotbeexpectedtocomplywithdifferingandattimesconflictingprivacyrules.Ananalysisearlierthisyearof751U.S.andinternationalWebsitesconductedbyConsumersInternationalfoundthatmostsitescollectpersonalinformationbutfailtotellconsumershowthatdatawillbeusedhowsecurityismaintainedandwhatrightsconsumershaveovertheirowninformation.AtaminimumCongressshouldpasslegislationrequiringWebsitestodisplayprivacypoliciesprominentlyinformconsumersofthemethodsemployedtocollectclientdataallowcustomerstooptoutOfsuchdatacollectionandprovidecustomeraccesstotheirowndatathathasalreadybeencollected.AlthoughvariousInternetprivacybillswereintroducedinthe107thCongressthefocusshiftedtoexpandinggovernmentsurveillanceinthewakeoftheterroristattacks.Plainlygovernmenteffortstopreventterrorismareappropriate.Exactlyhowtheseexigentcircumstanceschangethenatureoftheonlineprivacydebateisstilltobeseen.Privacystandardsmadebyindividualstatesareineffectivebecause______.

Chronicinsomniaisamajorpublichealthproblem.Andtoomanypeopleareusing1therapiesevenwhilethereareafewtreatmentsthatdowork.MillionsofAmericans2awakeatnightcountingsheeporhaveastiffdrinkor3anpillhopingitwillmakethemsleepy.4expertsagreeallthatself-medicatingisabadideaandthecausesofchronicinsomniaremain5.a Chronicinsomniaisamajorpublichealthproblem.Andtoomanypeopleareusing1therapiesevenwhilethereareafewtreatmentsthatdowork.MillionsofAmericans2awakeatnightcountingsheeporhaveastiffdrinkor3anpillhopingitwillmakethemsleepy.4expertsagreeallthatself-medicatingisabadideaandthecausesofchronicinsomniaremain5. Almostathirdofadultshavetroublesleepingandabout10percenthave6ofdaytimeimpairmentthatsignaltrueinsomnia.But7thecomplaintsscientistsknowsurprisinglylittleaboutwhatcauseschronicinsomniaitshealthconsequencesandhowbesttotreatitapanelofspecialists8togetherbytheNationalInstitutesofHealthconcludedWednesday.Thepanelcalled9abroadrangeofresearchintoinsomnia10thatifscientistsunderstoodits11causestheycoulddevelopbettertreatments. Mostbutnotallinsomniaisthoughtto12otherhealthproblemsfromarthritisanddepressiontocardiovasculardisease.Thequestionofteniswhethertheinsomniacamefirstorwasaresultoftheotherdiseasesandhowtroublesleepingin13complicatesthoseotherproblems.Otherdiseases14theriskofinsomniaseemstoincreasewithageandtobemore15amongwomenespeciallyaftertheir50s.Smokingcaffeineandnumerous16drugsalsoaffectsleep. TheNIHisspendingabout$200millionthisyearonsleep-relatedresearchsome17tospecificdisordersandothers18theunderlyingscientificlawsthatcontrolthenervoussystemofsleep.Theagencywas19thepane’sreviewbeforedecidingwhatadditionalworkshouldbe20atinsomnia. 17

OneofthemostpressingchallengesthattheUnitedStates—andindeedtheworld—willfaceinthenextfewdecadesishowtoalleviatethegrowingstressthathumanactivitiesareplacingontheenvironment.Theconsequencesarejusttoogreattoignore.Wildlifehabitatsarebeingdegradedordisappearingaltogetherasnewdevelopmentstakeupmoreland.PlantandanimalspeciesarebecomingextinctatagreaterratenowthanatanytimeinEarth’shistory.Asmanyas30percentoftheworld’sfishstocksareoverexploited.Andthelistgoeson.Yetthereisreasontohavehopeforthefuture.Advancesincomputingpowerandmolecularbiologyareamongthetremendousincreasesinscientificcapabilitythatarehelpingresearchersgainabetterunderstandingoftheseproblems.Recentdevelopmentsinscienceandtechnologycouldprovidethebasisforsomemajorandtimelyactionsthatwouldimproveourunderstandingofhowhumanactivitiesaffecttheenvironment.Onepriorityforresearchisimprovinghydrologicalforecasting.Ithasbeenestimatedthattheworld’swaterusecouldtripleinthenexttwodecades.AlreadywidespreadwatershortageshaveoccurredinpartsofChinaIndiaNorthAfricaandtheArabianPeninsula.TheneedforwateralsoistakingitstollonfreshwaterecosystemsintheUnitedStates.Only2percentofthenation’sstreamsareconsideredingoodconditionandcloseto40percentofnativefishspeciesareraretoextinct.Usingavarietyofnewremotesensingtoolsscientistscanlearnmoreabouthowprecipitationaffectswaterlevelshowsurfacewaterisgeneratedandtransportedandhowchangesinthelandscapeaffectwatersupplies.Topreventoutbreaksofinfectiousdiseasesinplantsanimalsandhumansmorestudyisneededonhowpathogensparasitesanddisease-carryingspecies—aswellashumansandotherspeciestheyinfect—areaffectedbychangesintheenvironment.Theoveruseofantibioticsbothinhumansandinfarmanimalshascontributedtothegrowthofantibiotic-resistantmicroorganisms.Researcherscantakeadvantageofnewtechnologiesingeneticsandcomputingtobettermonitorandpredicttheeffectsthatenvironmentalchangesmighthaveondiseaseoutbreaks.HumanshavemadealterationstoEarth’ssurface—suchastropicaldeforestationreductionofsurfaceandgroundwaterandmassivedevelopment—sodramaticthattheyapproachthelevelsoftransformationthatoccurredduringglacialperiods.Suchalterationscausechangesinlocalandregionalclimateandwilldeterminethefutureofagriculture.Recentadvancesindatacollectionandanalysisshouldbeusedtodocumentandbetterunderstandthecausesandconsequencesofchangesinlandcoveranduse.Throughoutthetexttheauthormainlyemphasizes

Chronicinsomniaisamajorpublichealthproblem.Andtoomanypeopleareusing1therapiesevenwhilethereareafewtreatmentsthatdowork.MillionsofAmericans2awakeatnightcountingsheeporhaveastiffdrinkor3anpillhopingitwillmakethemsleepy.4expertsagreeallthatself-medicatingisabadideaandthecausesofchronicinsomniaremain5.a Chronicinsomniaisamajorpublichealthproblem.Andtoomanypeopleareusing1therapiesevenwhilethereareafewtreatmentsthatdowork.MillionsofAmericans2awakeatnightcountingsheeporhaveastiffdrinkor3anpillhopingitwillmakethemsleepy.4expertsagreeallthatself-medicatingisabadideaandthecausesofchronicinsomniaremain5. Almostathirdofadultshavetroublesleepingandabout10percenthave6ofdaytimeimpairmentthatsignaltrueinsomnia.But7thecomplaintsscientistsknowsurprisinglylittleaboutwhatcauseschronicinsomniaitshealthconsequencesandhowbesttotreatitapanelofspecialists8togetherbytheNationalInstitutesofHealthconcludedWednesday.Thepanelcalled9abroadrangeofresearchintoinsomnia10thatifscientistsunderstoodits11causestheycoulddevelopbettertreatments. Mostbutnotallinsomniaisthoughtto12otherhealthproblemsfromarthritisanddepressiontocardiovasculardisease.Thequestionofteniswhethertheinsomniacamefirstorwasaresultoftheotherdiseasesandhowtroublesleepingin13complicatesthoseotherproblems.Otherdiseases14theriskofinsomniaseemstoincreasewithageandtobemore15amongwomenespeciallyaftertheir50s.Smokingcaffeineandnumerous16drugsalsoaffectsleep. TheNIHisspendingabout$200millionthisyearonsleep-relatedresearchsome17tospecificdisordersandothers18theunderlyingscientificlawsthatcontrolthenervoussystemofsleep.Theagencywas19thepane’sreviewbeforedecidingwhatadditionalworkshouldbe20atinsomnia. 11

A是n阶矩阵且A3=0则______

In1999thepriceofoilhoveredaround$16abarrel.By2008ithad1the$100abarrelmark.Thereasonsforthesurge2fromthedramaticgrowthoftheeconomiesofChinaandIndiatowidespread3inoil-producingregionsincludingIraqandNigeria’sdeltaregion.Triple-digitoilpriceshave4theeconomicandpoliticalmapoftheworld5someoldnotionsofpower.Oil-richnationsareenjoyinghistoricgainsandopportunities6majorimporters—includingChinaandIndiahometoathirdoftheworldspopulation—7risingeconomicandsocialcosts. Managingthisneworderisfastbecomingacentral8ofglobalpolitics.Countriesthatneedoilareclawingateachotherto9scarcesuppliesandarewillingtodealwithanygovernment10howun-pleasanttodoit. Inmanypoornationswithoiltheprofitsarebeinglosttocorruption11thesecountriesoftheirbesthopefordevelopment.Andoilisfuelingenormousinvestmentfundsrunbyforeigngovernments12someinthewestseeasanewthreat. CountrieslikeRussiaVenezuelaandIranarewellsuppliedwithrisingoil13achangereflectedinnewlyaggressiveforeignpolicies.Butsomeunexpectedcountriesarereapingbenefits14costsfromhigherprices.ConsideringGermany15itimportsvirtuallyallitsoilithasprosperedfromextensivetradewithaboomingRussiaandtheMiddleEast.GermanexportstoRussia16128percentfrom2001to2006. IntheUnitedStatesasalreadyhighgaspricesrose17higherinthespringof2008theissuecroppedupinthepresidentialcampaignwithSenatorsMcCainandObama18forafederalgastaxholidayduringthepeaksummerdrivingmonths.Anddrivinghabitsbeganto19assalesofsmallcarsjumpedandmasstransportsystems20thecountryreportedasharpincreaseinriders 7

设y=1+sinxx则=______

设二维随机变量XY在区域D://0＜x＜1|y|=x内服从均均分布求关于X的边缘概率密度函数及随机变量Z=2X+1的方差DZ

Rewardsandpunishmentsareusedindifferentwaysbydifferentcommunitiestomaintainsocialorderandpreserveculturalvalues.Inallculturesparentsmustteachtheirchildrentoavoiddangerandtoobservethecommunity’smoralprecepts.Adultsalsoconditioneachother’sobservanceofsocialnormsusingmethodsrangingfrommildformsofcensuresuchaslookingawaywhensomeonemakesaninappropriateremarktoimprisoningorexecutingindividualsforbehaviorconsidereddeviantordangerous.ThecaningofAmericanteenagerMichaelFayinSingaporeforvandalismin1994broughtwidemediaattentiontoculturaldifferencesintheapplicationofpunishment.FacedwithincreasingviolenceathomemanyAmericansendorsedSingapore’suseofcorporalpunishmenttomaintainsocialorder.WasFay’spunishmenteffectiveWhetherhesubsequentlyavoidsvandalismisunknownbutthepunishmentdidapparentlyleadtohisavoidanceofSingapore—whichheleftpromptly. Theoperanttechniquessocietiesusetomaintainsocialcontrolvaryinpartwiththedangersandthreatsthatconfrontthem.TheGusiiofKenyawithahistoryoftribalwarfarefacethreatsnotonlyfromoutsidersbutalsofromnaturalforcesincludingwildanimals.Gusiiparentstendtorelymoreonpunishmentandfearthanonrewardsinconditioningappropriatesocialbehaviorintheirchildren.Caningfooddeprivationandwithdrawingshelterandprotectionarecommonformsofpunishment. IncontrasttheMixtecansofJuxtlahuacaMexicoareahighlycohesivecommunitywithlittleinternalconflictandsocialnormsthatencouragecooperation.TheirsocialpatternsappearadaptivefortheMixtecansaredominatedbythenearbySpanishMexicanswhocontroltheofficialgovernmentandmanyeconomicresourcesintheirregion.TheMixtecansdonotgenerallyimposefinesorjailsentencesorusephysicalpunishmenttodeteraggressionineitheradultsorchildren.Rathertheytendtorelyonsoothingpersuasion.Socialostracismisthemostfearedpunishmentandsocialtieswithinthecommunityareverystrongsoresponsesthatreinforcethesetiesareeffectiveinmaintainingsocialorder. IntheUnitedStatesfearofsocialostracismorstigmawasonceamorepowerfulforceinmaintainingcontroloverantisocialbehaviorespeciallyinsmallcommunities.Todayevenimprisonmentdoesnotappeartobeanadequatedeterrenttomanyformsofcrimeespeciallyviolentcrime.Althoughonereasonistheinconsistentapplicationofpunishmentanothermaybethefactthatimprisonmentnolongercarriestheintensestigmaitoncehadsothatprisonisnolongerasaneffectivepunishment. ThewordstigmaPara.4mostprobablymeans

AsksomeonetonameafamouspsychologistandchancesaretheywillpickSigmundFreud.Hisideasabouttheunconscious—asortofshadowybasementofthemindthatisinaccessibletorationalthoughtbutwhichneverthelessinfluencespeople’sbehaviour—arepartofpopularfolklore.Althoughitremainedpopularatdinnerpartiestheideaoftheunconsciousfelloutoffavouramong20th-centurypsychologiststhankstotheriseofmorescientificapproachestopsychology.Thesefocusedpurelyonstudyingbehaviourandrefrainedfromtheorisingabouttheinnerworkingsofthemind.InhislatestbookSubliminalLeonardMlodinowatheoreticalphysicistshowshowtheideaoftheunconscioushasbecomerespectableagainoverthepastcoupleofdecades.Thisdevelopmenthasbeenhelpedbyrigorousexperimentalevidenceoftheeffectsofthesubconsciousandespeciallybyreal-timebrain-scanningtechnologythatallowsresearcherstoexaminewhatisgoingonintheirsubjects’heads.ThatexperimentalevidencesuggeststhatasFreudsuspectedconsciousreasoningmakesupacomparativelysmallpart.oftheactivityinourbrainswithmostoftheworktakingplacewherewecan’ttapintoit.HoweverunlikeFreud’sunconsciousthemodernunconsciousisaplaceofsuper-fastdataprocessingusefulsurvivalmechanismsandrulesofthumbabouttheworldthathavebeentrainedbymillionsofyearsofevolution.Itistheunconsciousforinstancethatstitchestogetherdataoncolourshapemovementandperspectivetocreatethesightenjoyedbytheconsciouspart.ofthemind.ThemodemviewoftheunconsciousmindmaybemorebenignthanFreud’sbutitcanstillgenerateunwelcomeimpulses.Psychologiststheorisethatthewell-documentedtendencyofhumanstocategorisealmosteverypieceofinformationtheycomeacrossisasurvivalmechanismthatevolvedtoaidquickdecisionmaking.Yetitmayalsoliebehindthetendencyforhumanbeingstogrouppeopleintoracesgenderscreedsandthelikeandthentoapplycertaincharacteristics—unjustifiably—toeverymemberofthatgroup.Theinsightsofferedbymodemscienceintotheworkingsofthehumanmindarefascinatingintheirownright.Buttheyalsosuggestthatplentyofconventionalwisdomabouthowhumansbehavemayneedrethinking.ForinstanceMrMlodinownotesthateconomicmodelsarebuiltontheassumptionthatpeoplemakedecisionsbyconsciouslyweighingtherelevantfactorswhereasthepsychologicalresearchsuggeststhatmostofthetimetheydonosuchthing.Insteadtheyactonthebasisofsimpleunconsciousrulesthatcansometimesproducecompletelyirrationalresults.

设fx为连续函数计算其中D是由y=x3y=1z=-1围成的区域

设A为n阶方阵A*为A的伴随矩阵且A11≠0证明方程组Ax=bb≠0有无穷多解的充要条件中b为A*X=0的解