托福必备科学美国人101Word格式.docx

托福必备科学美国人101Word格式.docx

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Biologistsbelievethatsexoffersanevolutionaryadvantagebecauseitpromotesgeneticdiversity.Comingupwithfreshnewgenecombinationsshouldalloworganismstooutsmartparasites,whicharealsocontinuouslyevolving.Butifthattheoryiscorrectthenbdelloidrotifers,freshwaterinvertebratesthathaven’thadsexinatleast30millionyears,shouldhavebeenparasitedintoextinctionlongago.Yetheretheyare,aliveandwell.

Tofindoutwhy,scientistsinfectedrotiferswithadeadlyfungus.Andtheyfoundthatbdelloidrotiferscanshaketheinfectionbydryingout,driftingawayandthenrehydratingoncetheylandsomeplacemoistbutfungus-free.Thefungidon’tsurvivethedesiccation,sothelongerthebdelloidsstaydry,thebetterofftheybe.

Soforcelibaterotifersthatwanttostayclean,agoodlongdryspellisjustwhatthedoctorordered.

—KarenHopkin

Imagineaworldwithlevitatingcars,MRIsthesizeoflaptops,andwidescaleefficientenergydistribution.ThesemightnotbepipedreamsifscientistscancapitalizeonafindinginthejournalNature.Superconductorscarryelectricitywithnolosstoresistance.Theyaretoregularconductorswhatalaserbeamistoalightbulb.Theproblemistheyhavetobecooledtoatleast–100degreesCelsiustowork.Thentheelectronsspontaneouslystartmovinginonedirectionandformingpairs.Andnow,scientistshavecaughtaglimpseofamysteriousphasetheycallthe“pseudo-gap”wheretheelectronslineupjustbeforetheyformpairsandstartsuperconducting.LouisTailleferfromtheUniversityofSherbrookesaidtheyusedamagneticfieldtoaligntheelectronflow:

“Theeffectwasverybig.Itwassurprisinglybig.”Ifscientistscantakeadvantageofthiseffect,roomtemperaturesuperconductorscouldbeastepcloser.“Ifwedofindorifwedoarriveatamaterialthatcansustainsuperconductivityatroomtemperaturewewillhaveahugetechnologicalrevolution,similaronascaletothetransistor.”

—SonyaBuyting

ListeningWhileDrivingIs,What'

dYaSay?

Weallknowthattalkingonacellphonecanimpairourabilitytodrive（althoughtoomanyofusdoitanyway）.NowastudyinthejournalPsychonomicBulletinandReviewshowsthatthereverseisalsotrue:

drivingmakesithardtokeeptrackofwhatwe’retalkingabout.

Previousstudieshadfoundthatmotoristsareabletoconversejustfine.ButtoGaryDelloftheUniversityofIllinoisthatfindingjustdidn’tmakesense.Becausecomprehendingspeechrequiresattention,asdoessteeringthefamilysedan.SoDelldidastudyinadrivingsimulator.

Ninety-sixparticipantswerepairedup,withonetakingthewheelwhiletheothersatinthepassengerseatortalkedtothedriveronahands-freephone.Eachparticipantlistenedtoandwasaskedtorepeatahandfulofstories,andthentorememberthemaftergettingoutofthecar.Asyoucanimagine,thedrivershadatoughertimerecallingthedetailsthanthepassengers.AndtheirconversationalskillstookthebiggestnosedivewhiletheyweretryingtonavigateintersectionsorhandletrafficNext,maybethescientistswilldeterminewhetherdrivingalsoimpairsourabilitytosing,eatbreakfast,andputonmakeup.And,ofcourse,text.

Cleopatra'

sEyeliner:

PeeperHealthKeeper

WhenyoupictureancientEgyptianbeautiessuchasQueenNefertitiorCleopatra,they’reprobablywearingdramaticblackeyeliner.AncientEgyptiansbelievedthateyemakeuphadpropertiesbestowedbythegodsprotectedthewearersfromillness.Modernscientistsdeterminedthatthemakeupcontainsoften-harmfullead,sotheydiscountedanybeneficialeffects.ButaccordingtoresearchpublishedinthejournalAnalyticalChemistry,theeyemakeupmayindeedhavepreventeddisease.

Scientistsanalyzed52differentsamplesfromancientEgyptianmakeupfoundattheLouvre.Theyidentifiedfourdifferentlead-basedsubstances,twoofwhichwereman-made,notnatural.Theythenappliedthesubstancestoacultureofhumancells.Andthecellsexperienceda240percentincreaseintheproductionofnitricoxide,whichisknowntojumpstarttheimmunesystem.

TheancientmarshyNilewouldhavehostedmanyeyedisease–causingbacteria.Applicationofthemakeupmayhaverevvedupcells’immunityandprotectedagainstinfection.Thechemicalcompoundswerenodoubtusedinitiallybasedonappearance.Butthenwearersnoticedtheyweren’tgettingeyeinfections.Thegodsgotpraised,butitwasancientchemistswhodeservedthecredit.

—CynthiaGraber

FrenchFriesontheCornySide

EverwonderwhatyourFrenchfrieswerefriedin?

Likebumblingburglarswholeavefingerprintsatacrimescene,cookingoilsleavetheirownclues.AndbymeasuringthecarbonisotopesinFrenchfries,UniversityofHawaiiresearchersfoundthatoneoiltopsallothersasthechoicetofryfriesin:

cornoil.That’saccordingtoareportintheProceedingsoftheNationalAcademyofSciences.

Nationalchainrestaurantstypicallyrevealonlythatfriesmaycontainoneormoreofthefollowingoils:

corn,canola,soybean,cottonseed,sunflowerandpalm.Butconsumersmightlikealittlemoreinfo:

inamealofburger,friesandsoda,20percentofthetotalcaloriescomefromtheoilthatfriedthepotatoes.

Analyzingfriesfromnearly200Hawaiianrestaurants,thescientistsfoundthat69percentofthenationalchainoutletsusedcornoil,comparedwithjust20percentofindependenteateries.

Cornoilisprobablytheleasthealthyoftheoilsmentioned,withmoreharmfulsaturatedfatsthancanolaorsunflowerandfewerheart-healthycompoundsthansoybean.Ofcourse,regardlessofwhatthey’refriedin,Frenchfriesprobablyaren’tonyourdiet.Thenagain,you’reprobablynotonyourdieteither.

ArtificialMuscleBringsBackBlink

Mostofusblinkwithoutthinking.Butpeoplewho’vesustainedstrokesorcombatinjuriescanlosetheirabilitytoblink.Whichisimportantforlubricatingandcleaningtheeye.Surgeryisanoption—asmallpieceofmuscletransplantedfromthelegcansometimeswork.Buttheoperationtakes10hoursandhasitsowndangers.SoscientistsattheUniversityofCalifornia,Davis,MedicalCenteraredevelopingartificialmusclestohelppatientsblinkagain,workdiscussedintheArchivesofFacialPlasticSurgery.

Theblinksystemstartswithwhatresearcherscallaneyelidsling,asmallpieceofmuscleorfabricthatholdstheeyelid.Theslingattachestobonearoundtheeye.It’sthenlinkedtoanelectrostaticpolymer—basicallyapieceofflexibleplasticthatexpandsorcontractsviavoltagechange.Atinybatteryhiddeninanaturalhollowinthetemplepowersthepolymer.Electricalcurrentkeepsthemusclescontractedandtheeyesopen.Killthecurrentandthelidcloses.

Here’sthecreepypart—themechanism’sbeentestedoncadavers,whichareblinkingaway.Butnowthattheprincipleisproven,inthenextyearsrealpatientscouldbeonthebrinkofablink.—CynthiaGraber

RunningShoesJogJoints

Yourfeetmayloverunningshoes.Butwhatabouttherestofyourbody?

Newresearchfindsthatrunningshoesactuallyincreasethepressureonankles,kneesandhips—morethanhighheelscanduringwalking.That’saccordingtoastudyintheJournalofInjury,FunctionandRehabilitation.

Researchersenlisted68injury-freerunnerswhonormallyloggedatleast15milesaweek.Thesubjectsranattheirownpaceonatreadmill,firstinmodernrunningshoesandthenagainbarefoot.Itturnsoutthatrunningshoesuppedthepressure,ortorque,onkneejointsby38percentoverbarefeet.Hipsexperiencedapressureincreaseof54percent.Walkingininch-and-a-halfhighstilettosonlyworsenedkneetorquebyabout20percentinpreviousstudies.

Sincestressfuljointpressurecancauseosteoarthritis,shouldrunnersstarthittingthepavementinbarefeet?

Probablynot.True,someelitemarathonersdorunsanssneakers.Butapparentlylettingtherubberhittheroadislikevariousspiritualrituals:

toughonthebody,butgoodforthesole.

—MollyWebster

WhyDwarfGalaxiesLackStarPower

Forastronomerswhostudythelarge-scalestructureoftheuniverse,dwarfgalaxieshaveprovenquitevexing.Becausetheleadingmodelofcosmologyhasbeenunabletoaccountfortheirrelativelackofsubstance.NowscientistswritinginthejournalNatureshowthatthecurrentmodelcanactuallygeneratedwarfgalaxiesjustfine.Youjustneedtolookatthestars.

Therearetwotypesofmatterintheuniverse:

ordinarymatter,includingthematerialthatmakesupstars.Anddarkmatter:

thatmysteriousstuffwecan’tseebutthatclearlyaffectsordinarymatter.It’sthepresenceofcolddarkmatterthatexplainshowtheyounguniversewentfrombeingsmoothtobeinglumpy,asordinarymattercoalescedfirstintostarsandthenintogalaxies.Theproblemisthatdwarfgalaxiesarenotasdenseasthecolddarkmattermodelsaystheyshouldbe.

Nowaninternationalteamofastronomerssaysyoucanblamegustsofstellarwind.Becauseintheroilingcauldronofactivitythatgovernsgalaxyformation,somestarsgosupernova.Thosespectacularexplosionsliterallyblowmatteraway,andyou’releftwithadwarfgalaxythat’salotlikemostindependentfilms:

abitlightonstars.

DoAllAnimalsSoundtheSame?

Whatdoawhaleandafroghaveincommon?

AccordingtoastudypublishedintheProceedingsofthe