SSS听力文本汇总.docx

SSS听力文本汇总.docx

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SSS听力文本汇总

DoCardiovascularImplantsGetEnoughTesting?

ApaperintheJournaloftheAmericanMedicalAssociationpointsoutthatmanyimplantablecardiovasculardevicesappeartogetFDApremarketapprovalwithoutwhattheauthorsconsidertobesufficientpublishedtestresults.CynthiaGraberreports

Weliketothinkthatmedicalequipmentimplantedinourbodiesundergoesrigoroustestingbeforeit’sputinsideaperson.That’snotalwaysthecase,atleastforcardiovasculardevices.That’saccordingtoanarticleintheJournaloftheAmericanMedicalAssociation.

ResearchersevaluatedtheFDApremarketapprovalprocessfor78high-riskdevices,suchaspacemakers,stentsandimplanteddefibrillators.Theyhadassumedthatthesetypesofdevicesshouldandwouldbesubjecttorandomdouble-blindedstudieswithcontrolsoveranappropriatetime-frametoinvestigatesafetyandefficacy.

Butfor51ofthedevices—65percent—approvalwasbasedonasinglestudy.Only27percentofstudieswererandomized,andonly14percentwereblinded.Onlyhalfofthedeviceswerecomparedwithcontrols.

Theauthorsrecognizethetensionbetweensufficienttestingandtheneedtogetnewdrugsanddevicestothepublic.But,theysay,“Thebarforevidenceofbenefitshouldbehigherfordevicesbecausetheyareimplantedandcannotsimplybediscontinued,asdrugscan.Inaddition,althoughdevicescanbelifesaving,theyalsohavegreatpotentialforriskandadverseevents.”

—CynthiaGraber 

ComputersCan'tShowYoutheMonet

AstudyinthejournalComputers&Graphicsfindsthatcomputerprogramsforidentifyingworksofartfallfarshortofevennonexperthumanjudges,becauseofourabilitytopsychologicallyevaluatescenes.MollyWebsterreports

Nosurprise:

machinesandhumanshavedifferingopinionsaboutart.ResearchersfromtheMaxPlanckInstituteandtheUniversityofGironahadcomputersandnon-artexperthumansplaceeachof275paintingsintooneof11artisticperiods,forexample,BaroqueorSurreal.And,unlikeinchess,peoplefaroutshonetheirsiliconcompetitors.That’saccordingtoastudyinthejournalComputers&Graphics.

Computeralgorithmsjudgedtheartbyobviousandquantifiableparameters,suchasthewaythepaintwaslaidonthecanvas,orthecolorcomposition.Buthumansclassifiedartbasedoncomplexpsychologicalevaluation.Weaskquestionssuchas,whoisintheimage?

And,whatemotionsarebeingportrayedinthescene?

Thiskindofanalysisiscrucialforcorrectlyidentifyingart—becauseevennon-expertpeoplewererighttwothirdsofthetime,farbetterthantheircomputercompetitors.Andthatmakessense:

ultimately,artisaboutouremotionalreactiontoaStarryNightoraGirlWithAPearlEarring.Buttoacomputerit’salljustbrushstrokes.

—MollyWebster

AnimalMimics:

MoreThanJustCamouflage

AstudyinthejournalSciencefindsthatanimalsthatusemimicry--forexample,aninsectcloselyresemblingatwig--areindeedseenandignoredbypredators,notmerelymissedbythemasacamouflagedinsectwouldbe.KarenHopkinreports

January5,2010 

Sometimesitpaystolooklikeapileofpoop.Atleastifyou’reatastycaterpillartryingtoavoidgettingeatenbyhungrybirds.BecauseastudyinthejournalScienceshowsthatevenyoungchickstendtooverlookcaterpillarsdisguisedasdung.

Animalshavecomeupwithsomeprettyclevertricksforkeepingthemselvesoffapredator’sdinnerplate.Someusecamouflage,adoptingcolorsandpatternsthathelpthemblendintotheenvironment.Othersmasqueradeassomethinginedible,likebirddroppingsortwigs.Butscientistsgottowonderingwhetherthetwoapproachesarereallysodifferent.Maybecrittersdressedastwigsalso“blendin”sothatpredatorsjustdon’tseethem.Tofindout,scientistspresentedsometwiggy-lookingcaterpillarstotwosetsofhand-rearedchicks.Theyfoundthatbabybirdsthathadneverseensticksbeforegobbledthosebadboysrightup.Butchickswhowereshownrealtwigsfirsttookmuchlongertopeckatthemimics,anddidsomoregingerlythantheirnaïvefriends.

Thatmeansthebirdscouldseethecaterpillars,butwerefooledbythecostume,atleasttemporarily.Which,foracaterpillaronaleafinthewild,couldmeanthedifferencebetweeneatingandbeingeaten.

—KarenHopkin 

AlanAldaLooksfor"TheHumanSpark"

TheHumanSpark,athree-partPBSserieshostedbyAlanAldaanddebutingJanuary6th,looksatwhatmakeshumanstheexceptionallyunusualanimalsweare.SteveMirskyreports

January6,2010 

“For11years,IwasthehostofthepublictelevisionseriesScientificAmericanFrontiers.”That’sthefamiliarvoiceofAlanAlda,starofstage,screenandscience.NowAldaishostingathree-partpublicTVseriesaboutyou.Andme,andallofus.“We’llbetryingtogettothebottomofwhatmakesushuman.Tryingtofindthatthingwe’recallingthe‘humanspark’.”

Onewaytoexamineusisbylookingatwhat’salmostus.“We’llbecheckinginwithourclosestlivingrelatives,thechimpanzees,tofindouthowthetinydifferenceinourgenes,just1percent,makessuchahugedifferencetowhoweareandwhatwecando.Chimpsaresmartasawhip,butthey’renotus.Whyaren’tthey?

”

TheHumanSparkdebutsonPBSWednesday,January6th,withepisodestwoandthreeonthefollowingWednesdays,the13thand20th.“Wecan’tpromisewe’llfindthehumanspark,butwecanpromisethatlookingforitwillbefascinating.Anditmaychangethewayyouthinkaboutwhoyouare.”

--SteveMirsky

Astronomy'sSerendipitiousSide

InanarticleinthejournalScience,TuftsUniversityastronomerKennethLangcataloguesthediscoveriesaboutouruniversethatweremadebyhappyaccident.KarenHopkinreports

January7,2010 

You’veheardthesaying“thankyourluckystars.”Well,intheJanuary1stissueofScience,astronomerKennethLangofTuftsUniversitysaysit’snotthestarsthatarelucky,butthefolkswhostudythem.Becausesomeofthebiggestdiscoveriesaboutouruniversewerestumbledon.

Fourhundredyearsago,GalileoraisedhishomemadespyglasstotheskyandspottedfourofJupiter’smoons,revealingthatotherplanetscouldhavetheirownlunarcompanions.Later,theplanetUranusandthefirstasteroid,Ceres,werehappenedonbyscientistslookingforotherthings.Again,improvedinstrumentationledtothefinds.WhichLangsaysisacommonoccurrenceintheworldofskygazing.

Gammaraybursts—thoseenergeticexplosionsthatarethoughttoheraldthedeathofmassive,far-flungstars—werefirstseenbysatelliteslookingforcovertuseofnuclearweapons.

AndWilsonandPenziasdiscoveredthecosmicmicrowavebackgroundradiation,physicalevidencefortheBigBang,whilefiddlingwithanantennadesignedtocatchradiowavesbouncingoffsatellites.Forrealizingwhattheywereactuallymeasuring,theygotaNobelPrize.AsYogiBerra,astarhimself,oncenoted,“Youcanobservealotjustbywatching.”

—KarenHopkin

MonkeysAreCanariesinLeadMine

InastudyintheAmericanJournalofPhysicalAnthropology,researchersshowedthatmacaquesthatlivesidebysidewithhumansinNepalshowelevatedleadlevelsintheirbodies.Thehumanpopulationisthusprobablyalsobeingexposedtounsafelead.CynthiaGraberreports

January8,2010 

You’veheardaboutthecanaryinthecoalmine.Andfrogsassignalsofenvironmentaldegradation.Thelatestanimaltoserveasaharbingeroftoxicexposurestohumansmaybe:

monkeys.That’saccordingtoresearchintheAmericanJournalofPhysicalAnthropology.

MacaquesliveinclosequarterswithpeopleinpartsofNepal.Soscientiststhoughtthatthemonkeysmightbe“sentinels”forhumanleadexposure.Leadcanhavemultipledeleterioushealtheffects,fromimpairingneurologicaldevelopmenttokidney,liver,andcirculatoryandrespiratoryproblems.

Theresearchteamwantedtoavoidstressingtheanimals,sotheytookafewstrandsofhairfromindividualslivingaroundatempleinKatmandu.It’sinadenselypopulatedareathatcontainsoldleadbatteries,flakinglead-basedpaint,andlead-contaminatedsoil,aby-productofleadedgas.Leadlevelsvariedinthemacaques,butthehighestconcentrationswereintheyoung—likehumanchildren,youngmacaquestendtopickupobjectsandstickthemintheirmouths.

Scientistssaythey’llnexttrytonaildownwhethermacaqueleadlevelsareindeedpredictiveofleadpoisoninginhumans.Thehopeisthatmonitoringmacaqueleadcanimproveconditionsforhumansandmonkeysalike.

—CynthiaGraber

SheddingLightonMigraine

Evensomeblindpeoplearesensitivetolightwhenenduringamigraine.InastudyinthejournalNatureNeuroscience,researchersstudiedblindpeople,andfoundagroupofneuronsthatgetsactivatedduringamigraine,whichcouldleadtotreatments.CynthiaGraberreports

January11,2010

Whenpeoplesufferfromamigraine,theyoftenretiretoacave-likedarkroom.Butexactlywhydoesbrightlighthurtthemigrainesufferer?

ApossibleanswerwaspublishedthisweekintheonlineissueofjournalNatureNeuroscience.Abigcluewasthatevensomeoftheblindmigrainevictimsavoidlight.

Migrainepainisthoughttocomefromirritationofthemeninges,membranesaroundthebrainandcentralnervoussystem.Soresearcherstooktwogroupsofblindmigrainesufferers.Onegroupwastotallyblind.Theothergroupwaslegallyblindbutcouldstillmakeoutlightanddark.

Thetotallyblindgroupdidnotsufferfromwhat’scalledphotophobia.Butlightdidaggravatethemigrainesofthelegallyblindgroup.Researchersthussuspectedagroupoflight-sensingretinalcellsthathelpregulatesleepingandwaking,becausethesearetheonlyactiveligh