英语听力听写练习原文.docx
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英语听力听写练习原文.docx
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英语听力听写练习原文
英语听力听写练习原文
〈2014.7〉第一集
1.
OceanPlasticParticlesCouldGetinGills
Seacreatureseatplasticdumpedintheocean,buttheyalsomightbeaccumulatingplasticbysuckinguptinyparticleswiththeirsiphonsandgills.ChristopherIntagliatareports.
Therearenowatleastfivemajorgarbagepatchesintheworld'soceans,andmuchofthattrashisplastic.Butlastmonthresearcherssaidtheycanonlyaccountforonepercentoftheplasticthey'dexpecttofindintheoceans.So,where'dtherestofitgo?
Well,animalseatsomeofit.Plastichasbeenfoundinturtles,seabirds,fish,plankton,shellfish,evenbottom-feedinginvertebrates.Butthere'sanotherwayseacreaturesmightbeaccumulatingplastic:
bysuckinguptinyplasticparticleswiththeirsiphonsandgills.
Researchersaddedcommonshorecrabs—Carcinusmaenas—totanksofseawatercontainingmillionsoftinyplasticparticles,just10micronsindiameter.After16hours,allthecrabshadplasticlodgedintheirgills.Andtheparticlesstuckaroundforuptothreeweeks,too.TheresultsareinthejournalEnvironmentalScienceandTechnology.[AndrewJ.R.Wattsetal,UptakeandRetentionofMicroplasticsbytheShoreCrabCarcinusmaenas]
Thelongerplasticsitsinananimal,researcherssay,thebetterthechancesitwilltravelupthefoodchain.Meaningallourplasticwastecouldcomebacktobiteus—orratherbebittenbyus.
"Ofcourseweeatmusselswhole,withouttheshells.Butwe'repotentiallyeatingplastic,ifthey'refromasitewherethere'splasticpresent."LeadresearcherAndrewWatts,oftheUniversityofExeter."Wedon'tknowhowmuchplasticwehaveinourstomachs…chancesarewedohavesome."
—ChristopherIntagliata
2.
Salmonella'sFavoriteFoodCouldBeItsAchilles'Heel
Salmonella'sprimaryfuelsourceisthemoleculefructose-asparagine.Starvingitofthatfuelinaninfectedpersoncouldkillitwithoutharmingbeneficialgutbacteria.KarenHopkinreports
Summer’shereandwithitcomepicnics,barbecuesandofcoursesalmonella.Thegermisnotoriousforcontaminatingavarietyoffavoritewarm-weatherfoods.Butthebacteria’spalateismorelimitedthanours.Oncesalmonellamakesitswayintoyoursystem,itreliesonasingleunusualnutrienttosurvive.That’saccordingtoastudyinthejournalPLoSPathogens.[MohamedM.Alietal,Fructose-AsparagineIsaPrimaryNutrientduringGrowthofSalmonellaintheInflamedIntestine]
Mostpeopletoughitoutwhentheygetfoodpoisoningfromsalmonella.That’sbecausetreatmentwithantibioticswouldeliminatetheinfection,butalsogetridofthegutbacteriathatpromotegoodhealth.
Tofigureouthowtotargetsalmonellaspecifically,researchersscreenedforgenesvitalforthemicrobe’ssurvivalduringtheactivephaseofinfection.Andtheyidentifiedaclusteroffivegenesthatworktogethertoallowthebacteriatodigestamoleculecalledfructose-asparagine.Nootherorganismsareknowntousethischemicalforfuel,sostarvingsalmonellaofitcouldbeanewstrategyforfightingthisfoodbornebugwhileleavingdesirableintestinalinhabitantsunharmed.
Next,theresearchersplantoseewhichfoodscontainlargeamountsofsalmonella’sgo-tosnack.Butplease,don’tsendunsolicitedsamplesofAuntAgnes’seggsalad.
—KarenHopkin
3.
EducationLevelLinkedtoNearsightedness
InaGermanstudy,halfofthosewithauniversitydegreeweremyopiccomparedwithlessthanaquarteroffolkswhoquitafterhighschoolorsecondaryschool.KarenHopkinreports
Nothingsays“overeducatedegghead”likeapairofcoke-bottleglasses.Butevenclichéssometimeshitthenerdonthehead.Becauseanewstudyfindsthatnearsightednessislinkedtothenumberofyearsspentinschool.ThefindingscanbeviewedinthejournalOphthalmology.[AlirezaMirshahietal,MyopiaandLevelofEducation]
Inthepastcentury,theprevalenceofmyopia—science-speakforbeingabletoseeonlywhat’srightinfrontofyou—hasbeenontherise.Somuchsothatitcan’tallbeblamedongeekygenes.
Tonaildownthepotentialenvironmentalinfluences,researchersfocusedontheclassroom.Theygaveeyeexamstonearly5000GermansubjectsinaprojectcalledtheGutenbergHealthStudy.
Theresearchersfoundthatindividualswith13yearsofeducationweremoremyopicthanthosewhodidn’tgetpastprimaryschool.Andmorethanhalfofthosewithauniversitydegreecoulduseasetofspecs,comparedtolessthanaquarterofthefolkswhoquitafterhighschoolorsecondaryschool.
Allthatlearningtakesalotofreading.Whichitselfisassociatedwithnearsightedness.Orthenearsightedmaygravitatetowardpursuitseasiertosee—likehittingthebooks.Eitherway,seemsthatbeingagoodstudentmaynotrequiregreatpupils.
—KarenHopkin
4.
GiveUsThisDaytheBreadWheatGenome
Apreliminarymapofthebreadwheatgenomeincludesthelocationsofmorethan75,000genes.CynthiaGraberreports
WheathelpedcreatecivilizationintheMiddleEast.It’sastaplecropfor30percentoftheworld’spopulation.Andnow,withthepublicationoffourarticlesinthejournalScience,we’reclosetoadetailedunderstandingofthebreadwheatgenome.[KellyeEversoleetal,Slicingthewheatgenome]
Wheatistoughtosequence.It’sgonethroughmultiplehybridizations,makingitsgenomefivetimeslargerthanahumanone.Plustherearemanyredundancies:
morethan80percentofthegenomeismadeofrepeatedDNAsequences.Sothetypicalwhole-genomeshotgunapproach—breakinggenomesintosegmentsandthenreassemblingthem—doesn’tworkforwheat.
Instead,aninternationalconsortiumdevisedanotherstrategy,involvingphysicallymappingindividualchromosomesandchromosomearms.
Onepaperdetailsadraftoftheentiregenomeofbreadwheat.Anotheridentifiesallthegenesonthelargestoftheplant’s21chromosomes.Some75,000geneshavebeenmapped.Themethodsinthesecondpaperwillhelpscientistsmaptheremainingchromosomes.Theysayitshouldtakeanotherthreeyears.
Knowingexactlywhichgenesareresponsiblefortalentssuchastoleratingdroughtorimprovingyieldsshouldallowresearcherstominethegenomeandtoquicklyproducenewandbetterwheatvarietiestobringusourdailybread.
—CynthiaGraber
5.
SupercooledOrgansCouldStretchTimetoTransplant
Livertransplanttimefromhumandonortopatientislimitedto12hours,butratsthatgotliversspeciallystoredforthreedaysweregoingstrongthreemonthslater.CynthiaGraberreports
Ifyouneedanewliver,doctorshaveabouttwelvehourstotransportitfromadonor.Thattickingclockseverelylimitstheabilityofdoctorstogetorganstopatients.
Nowresearchershavedemonstratedamethodthatkeptratliversviableuptofourdays.
Thescientistsloweredtheliverstobelowfreezingtemperatures,whilefloodingthetissuewithantifreezechemicalstopreventtheformationofdamagingicecrystals.
Butsuchcoolingaloneisnotsufficient,dueinparttotheliver’swidevarietyofcelltypesandfunctions.Sotheresearchersalsousedmachineperfusion:
astheliverswerecooledtheywereflushedwithsolutionsthatkeptthemoperational.Theywereperfusedagainastheywerebroughtbacktoabove-freezingtemps.
Alltheratsthatwereimplantedwith3-day-oldliverssurvivedforthreemonths.Nearly60percentoftheratswithfour-day-oldliverssurvived.Incontrast,noratsthatreceived3-and4-day-oldliverspreservedbycurrentlyusedmethodssurvived.[TimA.Berendsenetal,Supercoolingenableslong-termtransplantationsurvivalfollowing4daysofliverpreservation,inNatureMedicine]
Thisworkisanearlysteptowardcreatingasystemthatcouldworkinhumans,whichwoulddramaticallyimprovethechancesofgettingorganstopeoplewhodesperatelyneedthem.
—CynthiaGraber
6.
Space-BasedDataCollectionBetterPredictsFloods
Satellitedatacanhelpgeologistspredictmajorfloodsupto11monthsinadvanceinareaswheresnowmeltorgroundwaterisasignificantcontributor.CynthiaGraberreports
Wanttoknowwhere—andwhen—thenextmajorriverfloodwillhit?
Justlookup,tothesatellites.
Conventionalestimatesofrivervolumecomefromrainfall,ofcourse,andfrommeasurementofthewaterthatseepsfromsoilandgroundwaterreserves.
ButNASA’sGRACEsatellites,forGravityRecoveryandClimateExperiment,canpickupchangesinthegravityfieldinagivenriverbasin.Themorewaterinthebasin,thehigherthegravitysignal.
ScientistsusedGRACEresultsfrom2003to2012toseeiftheycouldhavepredictedthe500-yearfloodingeventintheMissouriRiverbasinin2011.Precedingthefloodweretwosignificantstorms,recordsnowmelt,saturatedsoilsandparticularlyhighgroundwater.
WithGRACEdata,theresearchersfoundthattheycouldhavepredictedtheMissouriRiverfloodsmonthsbeforecurrentpredictionmodels.Theysaythatthetechniquecouldbeusedtoforecastfloodsupto11monthsbeforesucheventstakeplaceinareaswheresnowmeltorgroundwaterisasignificantcontribution.
TheresearchwaspublishedinthejournalNatureGeoscience.[J.T.Reager,B.F.ThomasandJ.S.Famiglietti,RiverbasinfloodpotentialinferredusingGRACEgravityobservationsatseveralmonthsleadtime]
Snowmeltandmajorrainstormsarepredictedtoincreasewithclimatechange.Whichputsapremiumonbetterfloodprediction.
—CynthiaGraber
7.
MobilePhonesCarryOwners'Microbiomes
Thebacteriafoundonsomeone'smobilephoneisagoodmatchforthemostcommonkindsofbacteriathatliveontheirhands.ChristopherIntagliatareports
Thisyear,thenumberofmobilephonesoncellnetworksisexpe
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