首页
试卷库
试题库
当前位置：
X题卡
>
所有题目
>
题目详情
So Many ’Earths’ The Milky Way (银河) contains billions of...
查看本题答案
包含此试题的试卷
理工类《单选集》真题及答案
点击查看
你可能感兴趣的试题
热门试题
更多
Wewereattractedbythe{{U}}lure{{/U}}ofquickmoney.
I’llBeBach ComposerDavidCopeistheinventorofacomputerprogramthatwritesoriginalworksofclassicalmusic.IttookCope30yearstodevelopthesoftware.Nowmostpeoplecan’t_____51thedifferencebetweenmusicbythefamousGermancomposerJ.S.Bach1685-1750andtheBach-likecompositionsfromCope’scomputer. Itallstartedin1980intheUnitedStateswhenCopewastryingtowriteanopera.Hewashaving_____52thinkingofnewmelodiessohewroteacomputerprogramtocreatethemelodies.Atfirstthismusicwasnot_____53tolistento.WhatdidCopedo?Hebegantorethinkhowhumanbeingscomposemusic.Herealizedthatcomposersbrains_____54likebigdatabases.Firsttheytakeinallthemusicthattheyhaveeverheard.Thentheytake_____55themusicthattheydislike.Finallytheymakenewmusicfromwhatis_____56.AccordingtoCopeonlythegreatcomposersareabletocreatethedatabaseaccuratelyrememberitandformnewmusicalpatternsfromit. Copebuilta_____57databaseofexistingmusic.HebeganwithhundredsofworksbyBach.Thesoftwareanalyzedthedataa_____58itdownintosmallerpiecesandlookedforpatterns.Itthencombinedthe_____59intonewpatterns.BeforelongtheprogramcouldcomposeshortBach-likeworks.Theyweren’tgoodbutitwasastart. Copeknewhehadmoreworktodo-hehadawholeoperatowrite.Hecontinuedtoimprovethesoftware.Soonitcould_____60morecomplexmusic.Healsoaddedmanyothercomposersincludinghisownworktothedatabase. AfewyearslaterCope’scomputerprogramcalledEmmywasreadytohelphimwithhisopera.The_____61requiredalotofcollaborationbetweenthecomposerandEmmy.Copelistenedtothecomputer’smusicalideasandusedthe_____62thatheliked.WithEmmytheoperatookonlytwoweekstofinish.ItwascalledCradleFallinganditwasagreat_____63!Copereceivedsomeofthebestreviewsofhiscareerbutnooneknewexactly_____64hehadcomposedthework. SincethatfirstoperaEmmyhaswrittenthousandsofcompositions.CopestillgivesEmmyfeedbackonwhathelikesanddoesn’tlikeofhermusic_____65sheisdoingmostofthehardworkofcomposingthesedays!
I’llBeBach ComposerDavidCopeistheinventorofacomputerprogramthatwritesoriginalworksofclassicalmusic.IttookCope30yearstodevelopthesoftware.Nowmostpeoplecan’t_____51thedifferencebetweenmusicbythefamousGermancomposerJ.S.Bach1685-1750andtheBach-likecompositionsfromCope’scomputer. Itallstartedin1980intheUnitedStateswhenCopewastryingtowriteanopera.Hewashaving_____52thinkingofnewmelodiessohewroteacomputerprogramtocreatethemelodies.Atfirstthismusicwasnot_____53tolistento.WhatdidCopedo?Hebegantorethinkhowhumanbeingscomposemusic.Herealizedthatcomposersbrains_____54likebigdatabases.Firsttheytakeinallthemusicthattheyhaveeverheard.Thentheytake_____55themusicthattheydislike.Finallytheymakenewmusicfromwhatis_____56.AccordingtoCopeonlythegreatcomposersareabletocreatethedatabaseaccuratelyrememberitandformnewmusicalpatternsfromit. Copebuilta_____57databaseofexistingmusic.HebeganwithhundredsofworksbyBach.Thesoftwareanalyzedthedataa_____58itdownintosmallerpiecesandlookedforpatterns.Itthencombinedthe_____59intonewpatterns.BeforelongtheprogramcouldcomposeshortBach-likeworks.Theyweren’tgoodbutitwasastart. Copeknewhehadmoreworktodo-hehadawholeoperatowrite.Hecontinuedtoimprovethesoftware.Soonitcould_____60morecomplexmusic.Healsoaddedmanyothercomposersincludinghisownworktothedatabase. AfewyearslaterCope’scomputerprogramcalledEmmywasreadytohelphimwithhisopera.The_____61requiredalotofcollaborationbetweenthecomposerandEmmy.Copelistenedtothecomputer’smusicalideasandusedthe_____62thatheliked.WithEmmytheoperatookonlytwoweekstofinish.ItwascalledCradleFallinganditwasagreat_____63!Copereceivedsomeofthebestreviewsofhiscareerbutnooneknewexactly_____64hehadcomposedthework. SincethatfirstoperaEmmyhaswrittenthousandsofcompositions.CopestillgivesEmmyfeedbackonwhathelikesanddoesn’tlikeofhermusic_____65sheisdoingmostofthehardworkofcomposingthesedays!
I’llBeBach ComposerDavidCopeistheinventorofacomputerprogramthatwritesoriginalworksofclassicalmusic.IttookCope30yearstodevelopthesoftware.Nowmostpeoplecan’t_____51thedifferencebetweenmusicbythefamousGermancomposerJ.S.Bach1685-1750andtheBach-likecompositionsfromCope’scomputer. Itallstartedin1980intheUnitedStateswhenCopewastryingtowriteanopera.Hewashaving_____52thinkingofnewmelodiessohewroteacomputerprogramtocreatethemelodies.Atfirstthismusicwasnot_____53tolistento.WhatdidCopedo?Hebegantorethinkhowhumanbeingscomposemusic.Herealizedthatcomposersbrains_____54likebigdatabases.Firsttheytakeinallthemusicthattheyhaveeverheard.Thentheytake_____55themusicthattheydislike.Finallytheymakenewmusicfromwhatis_____56.AccordingtoCopeonlythegreatcomposersareabletocreatethedatabaseaccuratelyrememberitandformnewmusicalpatternsfromit. Copebuilta_____57databaseofexistingmusic.HebeganwithhundredsofworksbyBach.Thesoftwareanalyzedthedataa_____58itdownintosmallerpiecesandlookedforpatterns.Itthencombinedthe_____59intonewpatterns.BeforelongtheprogramcouldcomposeshortBach-likeworks.Theyweren’tgoodbutitwasastart. Copeknewhehadmoreworktodo-hehadawholeoperatowrite.Hecontinuedtoimprovethesoftware.Soonitcould_____60morecomplexmusic.Healsoaddedmanyothercomposersincludinghisownworktothedatabase. AfewyearslaterCope’scomputerprogramcalledEmmywasreadytohelphimwithhisopera.The_____61requiredalotofcollaborationbetweenthecomposerandEmmy.Copelistenedtothecomputer’smusicalideasandusedthe_____62thatheliked.WithEmmytheoperatookonlytwoweekstofinish.ItwascalledCradleFallinganditwasagreat_____63!Copereceivedsomeofthebestreviewsofhiscareerbutnooneknewexactly_____64hehadcomposedthework. SincethatfirstoperaEmmyhaswrittenthousandsofcompositions.CopestillgivesEmmyfeedbackonwhathelikesanddoesn’tlikeofhermusic_____65sheisdoingmostofthehardworkofcomposingthesedays!
Theorganizationwas{{U}}bold{{/U}}enoughtofacethepress.
Asalesman’s{{U}}cardinal{{/U}}ruleistosatisfycustomers.
I’llBeBach ComposerDavidCopeistheinventorofacomputerprogramthatwritesoriginalworksofclassicalmusic.IttookCope30yearstodevelopthesoftware.Nowmostpeoplecan’t_____51thedifferencebetweenmusicbythefamousGermancomposerJ.S.Bach1685-1750andtheBach-likecompositionsfromCope’scomputer. Itallstartedin1980intheUnitedStateswhenCopewastryingtowriteanopera.Hewashaving_____52thinkingofnewmelodiessohewroteacomputerprogramtocreatethemelodies.Atfirstthismusicwasnot_____53tolistento.WhatdidCopedo?Hebegantorethinkhowhumanbeingscomposemusic.Herealizedthatcomposersbrains_____54likebigdatabases.Firsttheytakeinallthemusicthattheyhaveeverheard.Thentheytake_____55themusicthattheydislike.Finallytheymakenewmusicfromwhatis_____56.AccordingtoCopeonlythegreatcomposersareabletocreatethedatabaseaccuratelyrememberitandformnewmusicalpatternsfromit. Copebuilta_____57databaseofexistingmusic.HebeganwithhundredsofworksbyBach.Thesoftwareanalyzedthedataa_____58itdownintosmallerpiecesandlookedforpatterns.Itthencombinedthe_____59intonewpatterns.BeforelongtheprogramcouldcomposeshortBach-likeworks.Theyweren’tgoodbutitwasastart. Copeknewhehadmoreworktodo-hehadawholeoperatowrite.Hecontinuedtoimprovethesoftware.Soonitcould_____60morecomplexmusic.Healsoaddedmanyothercomposersincludinghisownworktothedatabase. AfewyearslaterCope’scomputerprogramcalledEmmywasreadytohelphimwithhisopera.The_____61requiredalotofcollaborationbetweenthecomposerandEmmy.Copelistenedtothecomputer’smusicalideasandusedthe_____62thatheliked.WithEmmytheoperatookonlytwoweekstofinish.ItwascalledCradleFallinganditwasagreat_____63!Copereceivedsomeofthebestreviewsofhiscareerbutnooneknewexactly_____64hehadcomposedthework. SincethatfirstoperaEmmyhaswrittenthousandsofcompositions.CopestillgivesEmmyfeedbackonwhathelikesanddoesn’tlikeofhermusic_____65sheisdoingmostofthehardworkofcomposingthesedays!
LackofOxygenDelayedtheRiseofAnimalsonEarth Scientistshavelongspeculatedastowhyanimalspeciesdidn’tflourishsooneroncesufficientoxygencoveredtheEarth’ssurface.AnimalsbegantoprosperattheendoftheProterozoicperiodabout800millionyearsago—butwhataboutthebillion-yearstretchbeforethatwhenmostresearchersthinktherealsowasplentyofoxygen? Wellitseemstheairwasn’tsogreatthenafterall. InastudypublishedOct.31inScienceYaleresearcherNoahPlanavskyandhiscolleaguesfoundthatoxygenlevelsduringtheboringbillionperiodwereonly0.1%ofwhattheyaretoday.InotherwordsEarth’satmospherecouldn’thavesupportedadiversityofcreaturesnomatterwhatgeneticadvancementswerepoisedtooccur. ThereisnoquestionthatgeneticandecologicalinnovationmustultimatelybebehindtheriseofanimalsbutitisequallyunavoidablethatanimalsneedacertainlevelofoxygensaidPlanavskyco-leadauthoroftheresearchalongwithChristopherReinhardoftheGeorgiaInstituteofTechnology.We’reprovidingthefirstevidencethatoxygenlevelswerelowenoughduringthisperiodtopotentiallypreventtheriseofanimals. ThescientistsfoundtheirevidencebyanalyzingchromiumCrisotopesinancientsedimentsfromChinaAustraliaCanadaandtheUnitedStates.ChromiumisfoundintheEarth’scontinentalcrustandchromiumoxidationisdirectlylinkedtothepresenceoffreeoxygenintheatmosphere. Specificallytheteamstudiedsamplesdepositedinshallowiron-richoceanareasneartheshore.Theycomparedtheirdatawithothersamplestakenfromyoungerlocalesknowntohavehigherlevelsofoxygen. Oxygen’sroleincontrollingthefirstappearanceofanimalshaslongvexedscientists.WeweremissingtherightapproachuntilnowPlanavskysaid.Chromiumgaveustheproxy.Previousestimatesputtheoxygenlevelat40%oftoday’sconditionsduringpre-animaltimesleavingopenthepossibilitythatoxygenwasalreadyplentifulenoughtosupportanimallife. Inthenewstudytheresearchersacknowledgedthatoxygenlevelswerehighlydynamicintheearlyatmospherewiththepotentialforoccasionalspikes.HowevertheysaidItseemsclearthatthereisafirst-orderdifferenceinthenatureofEarthsurfaceCrcyclingbeforeandaftertheriseofanimals. Ifwearerightourresultswillreallychangehowpeopleviewtheoriginsofanimalsandothercomplexlifeandtheirrelationshipstotheco-evolvingenvironmentsaidco-authorTimLyonsoftheUniversityofCalifornia-Riverside.Thiscouldbeagamechanger. There’salotofinterestrightnowinabroaderdiscussionsurroundingtherolethatenvironmentalstabilityplayedintheevolutionofcomplexlifeandwethinkourresultsareasignificantcontributiontothatReinhardsaid.TimLyonslikedtoplaycomputergamesinhissparetime.
FirstImage-recognitionSoftware1.DartmouthresearchersandtheircolleagueshavecreatedanartificialintelligencesoftwarethatusesphotostolocatedocumentsontheInternetwithfargreateraccuracythaneverbefore.2.Thenewsystemwhichwastestedonphotosandisnowbeingappliedtovideosshowsforthefirsttimethatamachinelearningalgorithm运算法则forimagerecognitionandretrievalisaccurateandefficientenoughtoimprovelarge-scaledocumentsearchesonline.Thesystemusespixel像素datainimagesandpotentiallyvideo—ratherthanjusttext—tolocatedocuments.Itlearnstorecognizethepixelsassociatedwithasearchphrasebystudyingtheresultsfromtext-basedimagesearchengines.Theknowledgegleaned收集fromthoseresultscanthenbeappliedtootherphotoswithouttagsorcaptions图片说明makingformoreaccuratedocumentsearchresults.3."Overthelast30years"saysAssociateProfessorLorenzoTorresaniaco-authorofthestudy"theWebhasevolvedfromasmallcollectionofmostlytextdocumentstoamodernmassivefast-growingmultimediadatasetwherenearlyeverypageincludesmultiplepicturesorvideos.WhenapersonlooksataWebpageheimmediatelygetsthegist主旨ofitbylookingatthepicturesinit.YetsurprisinglyallexistingpopularsearchenginessuchasGoogleorBingstripawaytheinformationcontainedinthephotosanduseexclusivelythetextofWebpagestoperformthedocumentretrieval.Ourstudyisthefirsttoshowthatmodernmachinevisionsystemsareaccurateandefficientenoughtomakeeffectiveuseoftheinformationcontainedinimagepixelstoimprovedocumentsearch."4.Theresearchersdesignedandtestedamachinevisionsystem—atypeofartificialintelligencethatallowscomputerstolearnwithoutbeingexplicitlyprogrammed—thatextractssemantic语义的informationfromthepixelsofphotosinWebpages.ThisinformationisusedtoenrichthedescriptionoftheHTMLpageusedbysearchenginesfordocumentretrieval.Theresearcherstestedtheirapproachusingmorethan600searchqueries查询onadatabaseof50millionWebpages.Theyselectedthetext-retrievalsearchenginewiththebestperformanceandmodifiedittomakeuseoftheadditionalsemanticinformationextractedbytheirmethodfromthepicturesoftheWebpages.Theyfoundthatthisproduceda30percentimprovementinprecisionovertheoriginalsearchenginepurelybasedontext. Thenewsystemisexpectedtoimproveprecisionin
Sheshowedanatural{{U}}aptitude{{/U}}forthework.
FirstImage-recognitionSoftware1.DartmouthresearchersandtheircolleagueshavecreatedanartificialintelligencesoftwarethatusesphotostolocatedocumentsontheInternetwithfargreateraccuracythaneverbefore.2.Thenewsystemwhichwastestedonphotosandisnowbeingappliedtovideosshowsforthefirsttimethatamachinelearningalgorithm运算法则forimagerecognitionandretrievalisaccurateandefficientenoughtoimprovelarge-scaledocumentsearchesonline.Thesystemusespixel像素datainimagesandpotentiallyvideo—ratherthanjusttext—tolocatedocuments.Itlearnstorecognizethepixelsassociatedwithasearchphrasebystudyingtheresultsfromtext-basedimagesearchengines.Theknowledgegleaned收集fromthoseresultscanthenbeappliedtootherphotoswithouttagsorcaptions图片说明makingformoreaccuratedocumentsearchresults.3."Overthelast30years"saysAssociateProfessorLorenzoTorresaniaco-authorofthestudy"theWebhasevolvedfromasmallcollectionofmostlytextdocumentstoamodernmassivefast-growingmultimediadatasetwherenearlyeverypageincludesmultiplepicturesorvideos.WhenapersonlooksataWebpageheimmediatelygetsthegist主旨ofitbylookingatthepicturesinit.YetsurprisinglyallexistingpopularsearchenginessuchasGoogleorBingstripawaytheinformationcontainedinthephotosanduseexclusivelythetextofWebpagestoperformthedocumentretrieval.Ourstudyisthefirsttoshowthatmodernmachinevisionsystemsareaccurateandefficientenoughtomakeeffectiveuseoftheinformationcontainedinimagepixelstoimprovedocumentsearch."4.Theresearchersdesignedandtestedamachinevisionsystem—atypeofartificialintelligencethatallowscomputerstolearnwithoutbeingexplicitlyprogrammed—thatextractssemantic语义的informationfromthepixelsofphotosinWebpages.ThisinformationisusedtoenrichthedescriptionoftheHTMLpageusedbysearchenginesfordocumentretrieval.Theresearcherstestedtheirapproachusingmorethan600searchqueries查询onadatabaseof50millionWebpages.Theyselectedthetext-retrievalsearchenginewiththebestperformanceandmodifiedittomakeuseoftheadditionalsemanticinformationextractedbytheirmethodfromthepicturesoftheWebpages.Theyfoundthatthisproduceda30percentimprovementinprecisionovertheoriginalsearchenginepurelybasedontext. Paragraph2
What’skillingtheBats Firstitwasbees.Nowitisbats.BiologistsinAmericaareworkinghardtodiscoverthecauseofthemysteriousdeathsoftensofthousandsofbatsinthenortheasternpartofthecountry.MostofthebatsaffectedarethecommonlittlebrownbatsMyotislucifugusbutotherspeciessuchasthelong-earedbatthesmall-footedhattheeasternpipistrelleandtheIndianabathavealsobeenaffected.Insomecavesmorethan90percentofthebatpopulationshavedied. Onepossibilityisdisease.Awhitefungus真菌knownasfusariumhasbeenfoundonthenosesofbothlivinganddeadbats.Howeverscientistsdon’tknowIfthefungusistheprimarycauseofdeathasecondarycauseofdeathornotacauseatallbuttheresultofsomeotherconditions. Anotherpossiblecauseisalackoffood.Forexamplebatstypicallyeatalargenumberofmoths蛾andinsomestatessuchasNewYorkthenumberofmothshasbeendeclininginrecentyears.Ifbatscan’teatenoughfoodtheystarvetodeath. Stillotherscientistsbelievethatglobalwarmingistoblame.Warmertemperaturesinrecentyearshavebeenwakinguphibernating冬眠batsearlierthanusual.Ifbatsbreaktheirhibernationatthewrongtimetheymightnotfindtheirexpectedfoodsources.Theweathermightalsoturncoldagainandweakenorkillthebats. Scientistsmightnotagreeonthecausesofthebatdie-offbuttheydoagreeontheconsequences.Batsareanimportantpredatorofmosquitoes;asinglebrownbatcaneat1000ormoreinsectsinanhour.Theyalsoeatbeetlesandotherinsectsthatdamageplantcrops.Iftherearen’tenoughbatsdamagewillbegreatfromtheinsectstheyeatWhilebatslivealongtimefortheirsize－thelittlebrownbatcanliveformorethan30years－afemalebathasonlyonebabyperyearsobatpopulationsgrowslowly.ManybatspeciesintheUnitedStatesarealreadyprotectedorendangered. Howcanyouhelp?Donotdisturbsleepingornestingbats.IfyoudiscoverbatethatseemtobesickorthataredeadcontactyourlocalFish＆WildlifeDepartmentwiththedetails.Howeverbecarefulnottotouchtheanimals. ThewordpipistrelleinParagraph1refersto
I’llBeBach ComposerDavidCopeistheinventorofacomputerprogramthatwritesoriginalworksofclassicalmusic.IttookCope30yearstodevelopthesoftware.Nowmostpeoplecan’t_____51thedifferencebetweenmusicbythefamousGermancomposerJ.S.Bach1685-1750andtheBach-likecompositionsfromCope’scomputer. Itallstartedin1980intheUnitedStateswhenCopewastryingtowriteanopera.Hewashaving_____52thinkingofnewmelodiessohewroteacomputerprogramtocreatethemelodies.Atfirstthismusicwasnot_____53tolistento.WhatdidCopedo?Hebegantorethinkhowhumanbeingscomposemusic.Herealizedthatcomposersbrains_____54likebigdatabases.Firsttheytakeinallthemusicthattheyhaveeverheard.Thentheytake_____55themusicthattheydislike.Finallytheymakenewmusicfromwhatis_____56.AccordingtoCopeonlythegreatcomposersareabletocreatethedatabaseaccuratelyrememberitandformnewmusicalpatternsfromit. Copebuilta_____57databaseofexistingmusic.HebeganwithhundredsofworksbyBach.Thesoftwareanalyzedthedataa_____58itdownintosmallerpiecesandlookedforpatterns.Itthencombinedthe_____59intonewpatterns.BeforelongtheprogramcouldcomposeshortBach-likeworks.Theyweren’tgoodbutitwasastart. Copeknewhehadmoreworktodo-hehadawholeoperatowrite.Hecontinuedtoimprovethesoftware.Soonitcould_____60morecomplexmusic.Healsoaddedmanyothercomposersincludinghisownworktothedatabase. AfewyearslaterCope’scomputerprogramcalledEmmywasreadytohelphimwithhisopera.The_____61requiredalotofcollaborationbetweenthecomposerandEmmy.Copelistenedtothecomputer’smusicalideasandusedthe_____62thatheliked.WithEmmytheoperatookonlytwoweekstofinish.ItwascalledCradleFallinganditwasagreat_____63!Copereceivedsomeofthebestreviewsofhiscareerbutnooneknewexactly_____64hehadcomposedthework. SincethatfirstoperaEmmyhaswrittenthousandsofcompositions.CopestillgivesEmmyfeedbackonwhathelikesanddoesn’tlikeofhermusic_____65sheisdoingmostofthehardworkofcomposingthesedays!
I’llBeBach ComposerDavidCopeistheinventorofacomputerprogramthatwritesoriginalworksofclassicalmusic.IttookCope30yearstodevelopthesoftware.Nowmostpeoplecan’t_____51thedifferencebetweenmusicbythefamousGermancomposerJ.S.Bach1685-1750andtheBach-likecompositionsfromCope’scomputer. Itallstartedin1980intheUnitedStateswhenCopewastryingtowriteanopera.Hewashaving_____52thinkingofnewmelodiessohewroteacomputerprogramtocreatethemelodies.Atfirstthismusicwasnot_____53tolistento.WhatdidCopedo?Hebegantorethinkhowhumanbeingscomposemusic.Herealizedthatcomposersbrains_____54likebigdatabases.Firsttheytakeinallthemusicthattheyhaveeverheard.Thentheytake_____55themusicthattheydislike.Finallytheymakenewmusicfromwhatis_____56.AccordingtoCopeonlythegreatcomposersareabletocreatethedatabaseaccuratelyrememberitandformnewmusicalpatternsfromit. Copebuilta_____57databaseofexistingmusic.HebeganwithhundredsofworksbyBach.Thesoftwareanalyzedthedataa_____58itdownintosmallerpiecesandlookedforpatterns.Itthencombinedthe_____59intonewpatterns.BeforelongtheprogramcouldcomposeshortBach-likeworks.Theyweren’tgoodbutitwasastart. Copeknewhehadmoreworktodo-hehadawholeoperatowrite.Hecontinuedtoimprovethesoftware.Soonitcould_____60morecomplexmusic.Healsoaddedmanyothercomposersincludinghisownworktothedatabase. AfewyearslaterCope’scomputerprogramcalledEmmywasreadytohelphimwithhisopera.The_____61requiredalotofcollaborationbetweenthecomposerandEmmy.Copelistenedtothecomputer’smusicalideasandusedthe_____62thatheliked.WithEmmytheoperatookonlytwoweekstofinish.ItwascalledCradleFallinganditwasagreat_____63!Copereceivedsomeofthebestreviewsofhiscareerbutnooneknewexactly_____64hehadcomposedthework. SincethatfirstoperaEmmyhaswrittenthousandsofcompositions.CopestillgivesEmmyfeedbackonwhathelikesanddoesn’tlikeofhermusic_____65sheisdoingmostofthehardworkofcomposingthesedays!
FaceMasksMayNotProtectfromSuper-Flu Ifasuper-flustrikesfacemasksmaynotprotectyou.Whetherwidespreaduseofmaskswillhelporharmduringthenextworldwidefluoutbreakisaquestionthatresearchersarestudyingfuriously.Noresultshavecomefromtheirmaskresearchyet. Howeverthegovernmentsayspeopleshouldconsiderwearingthemcertainstationsanywayjustincase. Butit’saquestionthepublickeepsaskingwhilethegovernmentismakingpreparationsforthenextflupandemic大流行.SotheCentersforDiseaseControlandPreventionCDCcameupwithpreliminaryguidelines.Wedon’twantPeoplewearingthemeverywheresaidtheCDC.Theoverallrecommendationreallyistoavoidexposure. Whenthatisnotpossibletheguidelinessayyoushouldconsiderwearingasimplesurgicalmaskifyouareinoneofthethreefollowingsituations.Firstyou’rehealthyandcan’tavoidgoingtoacrowdedplace.Secondyou’resickandthinkyoumayhaveclosecontactwiththehealthysuchasafamilymembercheckingonyou.Thirdyoulivewithsomeonewho’ssickandthusmightbeintheearlystagesofinfectionbutstillneedtogoout. Influenzapandemicscanstrikewhentheeasy-to-mutate变异fluvirusshiftstoastrain菌株thatpeopleneverhaveexperienced.ScientistscannotpredictwhenthenextpandemicwillarrivealthoughconcernisrisingthattheAsianbirdflumighttriggeroneifitstartsspreadingeasilyfrompersontoperson. Duringtheflupandemicyoushouldprotectyourself.Avoidcrowdsandavoidclosecontactwiththesickunlessyoumustcareforsomeone.Whyaren’tmasksaddedtothisself-protectionlist?Becausetheycanhelptrapvirus-ladendropletsflyingthroughtheairwithacoughorsneeze.Simplesurgicalmasksonlyfilterthelargerdroplets飞沫.BesidestheCDCisafraidmasksmaycreateafalsesenseofsecurity.Perhapssomeonewhoshouldhavestayedhomewoulddon戴anill-fittingmaskandhoponthesubwayinstead. Nordoesfluonlyspreadthroughtheair.Saysomeonecoversasneezewithhisorherhandthentouchesadoorknoborsubwaypole.Ifyoutouchthatspotnextandthenputgermyhandsonyournoseormouthyou’vebeenexposed.It’shardertorubyournosewhilewearingamasksoyourfacemaygetprettysweatyundermasks.Youreachundertowipethatsweatandmaytransfergermscaughtontheoutsideofthemaskstraighttothenose.Thesearetheproblemsfacemasksmaycreatefortheirusers. Whetherpeopleshouldorshouldnotusefacemasksstillremainsaquestion.Thegeneralpublichastowaitpatientlyfortheresultsofthemaskresearchscientistsarestilldoing. Whichofthefollowingstatementsistrue?
LackofOxygenDelayedtheRiseofAnimalsonEarth Scientistshavelongspeculatedastowhyanimalspeciesdidn’tflourishsooneroncesufficientoxygencoveredtheEarth’ssurface.AnimalsbegantoprosperattheendoftheProterozoicperiodabout800millionyearsago—butwhataboutthebillion-yearstretchbeforethatwhenmostresearchersthinktherealsowasplentyofoxygen? Wellitseemstheairwasn’tsogreatthenafterall. InastudypublishedOct.31inScienceYaleresearcherNoahPlanavskyandhiscolleaguesfoundthatoxygenlevelsduringtheboringbillionperiodwereonly0.1%ofwhattheyaretoday.InotherwordsEarth’satmospherecouldn’thavesupportedadiversityofcreaturesnomatterwhatgeneticadvancementswerepoisedtooccur. ThereisnoquestionthatgeneticandecologicalinnovationmustultimatelybebehindtheriseofanimalsbutitisequallyunavoidablethatanimalsneedacertainlevelofoxygensaidPlanavskyco-leadauthoroftheresearchalongwithChristopherReinhardoftheGeorgiaInstituteofTechnology.We’reprovidingthefirstevidencethatoxygenlevelswerelowenoughduringthisperiodtopotentiallypreventtheriseofanimals. ThescientistsfoundtheirevidencebyanalyzingchromiumCrisotopesinancientsedimentsfromChinaAustraliaCanadaandtheUnitedStates.ChromiumisfoundintheEarth’scontinentalcrustandchromiumoxidationisdirectlylinkedtothepresenceoffreeoxygenintheatmosphere. Specificallytheteamstudiedsamplesdepositedinshallowiron-richoceanareasneartheshore.Theycomparedtheirdatawithothersamplestakenfromyoungerlocalesknowntohavehigherlevelsofoxygen. Oxygen’sroleincontrollingthefirstappearanceofanimalshaslongvexedscientists.WeweremissingtherightapproachuntilnowPlanavskysaid.Chromiumgaveustheproxy.Previousestimatesputtheoxygenlevelat40%oftoday’sconditionsduringpre-animaltimesleavingopenthepossibilitythatoxygenwasalreadyplentifulenoughtosupportanimallife. Inthenewstudytheresearchersacknowledgedthatoxygenlevelswerehighlydynamicintheearlyatmospherewiththepotentialforoccasionalspikes.HowevertheysaidItseemsclearthatthereisafirst-orderdifferenceinthenatureofEarthsurfaceCrcyclingbeforeandaftertheriseofanimals. Ifwearerightourresultswillreallychangehowpeopleviewtheoriginsofanimalsandothercomplexlifeandtheirrelationshipstotheco-evolvingenvironmentsaidco-authorTimLyonsoftheUniversityofCalifornia-Riverside.Thiscouldbeagamechanger. There’salotofinterestrightnowinabroaderdiscussionsurroundingtherolethatenvironmentalstabilityplayedintheevolutionofcomplexlifeandwethinkourresultsareasignificantcontributiontothatReinhardsaid.Theteamwasfundedbyseveralresearchinstitutes.
Therewasa{{U}}simultaneous{{/U}}trialtakingplaceinthenextbuild.
SavingaCity’sPublicArtAvoidingtrafficjamsinLosAngelesmaybeimpossiblebutthecity’scolorfulfreewaymurals壁画canbrighteneventheworstcommute.Paintingsthatdepict描述famouspeopleandhistoricalscenescoverofficebuildingsandfreewaywallsallacrossthecity.Withacollectionofmorethan2000muralsLosAngelesistheunofficialmuralcapitaloftheworld.Butthecombinationofgraffiti涂鸦pollutionandhotsunhasleftmanyL.A.muralsinterriblecondition._____46Inthepastexpertssaylittleattentionwasgiventocaringforpublicart.Artistswereevenexpectedtomaintaintheirownworksnotaneasytaskwithcarsracingbyalongthefreeway._____47Theworkstartedin2003.Sofar16wallshavebeenselectedandmoremaybeaddedlater.Untilabout1960publicmuralsinLosAngeleswererare.Butinthe1960sand1970syoungL. 49.
I’llBeBach ComposerDavidCopeistheinventorofacomputerprogramthatwritesoriginalworksofclassicalmusic.IttookCope30yearstodevelopthesoftware.Nowmostpeoplecan’t_____51thedifferencebetweenmusicbythefamousGermancomposerJ.S.Bach1685-1750andtheBach-likecompositionsfromCope’scomputer. Itallstartedin1980intheUnitedStateswhenCopewastryingtowriteanopera.Hewashaving_____52thinkingofnewmelodiessohewroteacomputerprogramtocreatethemelodies.Atfirstthismusicwasnot_____53tolistento.WhatdidCopedo?Hebegantorethinkhowhumanbeingscomposemusic.Herealizedthatcomposersbrains_____54likebigdatabases.Firsttheytakeinallthemusicthattheyhaveeverheard.Thentheytake_____55themusicthattheydislike.Finallytheymakenewmusicfromwhatis_____56.AccordingtoCopeonlythegreatcomposersareabletocreatethedatabaseaccuratelyrememberitandformnewmusicalpatternsfromit. Copebuilta_____57databaseofexistingmusic.HebeganwithhundredsofworksbyBach.Thesoftwareanalyzedthedataa_____58itdownintosmallerpiecesandlookedforpatterns.Itthencombinedthe_____59intonewpatterns.BeforelongtheprogramcouldcomposeshortBach-likeworks.Theyweren’tgoodbutitwasastart. Copeknewhehadmoreworktodo-hehadawholeoperatowrite.Hecontinuedtoimprovethesoftware.Soonitcould_____60morecomplexmusic.Healsoaddedmanyothercomposersincludinghisownworktothedatabase. AfewyearslaterCope’scomputerprogramcalledEmmywasreadytohelphimwithhisopera.The_____61requiredalotofcollaborationbetweenthecomposerandEmmy.Copelistenedtothecomputer’smusicalideasandusedthe_____62thatheliked.WithEmmytheoperatookonlytwoweekstofinish.ItwascalledCradleFallinganditwasagreat_____63!Copereceivedsomeofthebestreviewsofhiscareerbutnooneknewexactly_____64hehadcomposedthework. SincethatfirstoperaEmmyhaswrittenthousandsofcompositions.CopestillgivesEmmyfeedbackonwhathelikesanddoesn’tlikeofhermusic_____65sheisdoingmostofthehardworkofcomposingthesedays!
FirstImage-recognitionSoftware1.DartmouthresearchersandtheircolleagueshavecreatedanartificialintelligencesoftwarethatusesphotostolocatedocumentsontheInternetwithfargreateraccuracythaneverbefore.2.Thenewsystemwhichwastestedonphotosandisnowbeingappliedtovideosshowsforthefirsttimethatamachinelearningalgorithm运算法则forimagerecognitionandretrievalisaccurateandefficientenoughtoimprovelarge-scaledocumentsearchesonline.Thesystemusespixel像素datainimagesandpotentiallyvideo—ratherthanjusttext—tolocatedocuments.Itlearnstorecognizethepixelsassociatedwithasearchphrasebystudyingtheresultsfromtext-basedimagesearchengines.Theknowledgegleaned收集fromthoseresultscanthenbeappliedtootherphotoswithouttagsorcaptions图片说明makingformoreaccuratedocumentsearchresults.3."Overthelast30years"saysAssociateProfessorLorenzoTorresaniaco-authorofthestudy"theWebhasevolvedfromasmallcollectionofmostlytextdocumentstoamodernmassivefast-growingmultimediadatasetwherenearlyeverypageincludesmultiplepicturesorvideos.WhenapersonlooksataWebpageheimmediatelygetsthegist主旨ofitbylookingatthepicturesinit.YetsurprisinglyallexistingpopularsearchenginessuchasGoogleorBingstripawaytheinformationcontainedinthephotosanduseexclusivelythetextofWebpagestoperformthedocumentretrieval.Ourstudyisthefirsttoshowthatmodernmachinevisionsystemsareaccurateandefficientenoughtomakeeffectiveuseoftheinformationcontainedinimagepixelstoimprovedocumentsearch."4.Theresearchersdesignedandtestedamachinevisionsystem—atypeofartificialintelligencethatallowscomputerstolearnwithoutbeingexplicitlyprogrammed—thatextractssemantic语义的informationfromthepixelsofphotosinWebpages.ThisinformationisusedtoenrichthedescriptionoftheHTMLpageusedbysearchenginesfordocumentretrieval.Theresearcherstestedtheirapproachusingmorethan600searchqueries查询onadatabaseof50millionWebpages.Theyselectedthetext-retrievalsearchenginewiththebestperformanceandmodifiedittomakeuseoftheadditionalsemanticinformationextractedbytheirmethodfromthepicturesoftheWebpages.Theyfoundthatthisproduceda30percentimprovementinprecisionovertheoriginalsearchenginepurelybasedontext. Thenewsystemwasfoundmoreeffectiveindocumentsearchthanthe
SavingaCity’sPublicArtAvoidingtrafficjamsinLosAngelesmaybeimpossiblebutthecity’scolorfulfreewaymurals壁画canbrighteneventheworstcommute.Paintingsthatdepict描述famouspeopleandhistoricalscenescoverofficebuildingsandfreewaywallsallacrossthecity.Withacollectionofmorethan2000muralsLosAngelesistheunofficialmuralcapitaloftheworld.Butthecombinationofgraffiti涂鸦pollutionandhotsunhasleftmanyL.A.muralsinterriblecondition._____46Inthepastexpertssaylittleattentionwasgiventocaringforpublicart.Artistswereevenexpectedtomaintaintheirownworksnotaneasytaskwithcarsracingbyalongthefreeway._____47Theworkstartedin2003.Sofar16wallshavebeenselectedandmoremaybeaddedlater.Untilabout1960publicmuralsinLosAngeleswererare.Butinthe1960sand1970syoungL.A.artistsbegantostudyearly20th-centuryMexicanmuralpainting._____48ThemostfamousmuralinthecityisJudithBaca’s"TheGreatWall"a13-foot-high4-meter-highpaintingthatrunsforhalfamile0.8kilometerinNorthHollywood_____49ittookeightyearstocomplete—400underprivilegedteenagerspaintedthedesigns—andisprobablythelongestmuralintheworld.OneofthemuralsthatwillberestorednowisKentTwitchell’s"SeventhStreetAltarpiece."whichhepaintedfortheLosAngelesOlympicsin1984._____50Twitchellsaid"ItwasmeantasakindofgatewaythroughwhichthetravelertoL.A.mustdrive.Theopenhandsrepresentpeace."Artistsoftencallmuralsthepeople’sart.Alongabusyfreewayorhiddeninaquietneighborhoodmuralscanreachpeoplewhowouldneverpaymoneytoseefineartinamuseum"Muralsgiveavoicetothesilentmajority"saidoneartist. 47.
FaceMasksMayNotProtectfromSuper-Flu Ifasuper-flustrikesfacemasksmaynotprotectyou.Whetherwidespreaduseofmaskswillhelporharmduringthenextworldwidefluoutbreakisaquestionthatresearchersarestudyingfuriously.Noresultshavecomefromtheirmaskresearchyet. Howeverthegovernmentsayspeopleshouldconsiderwearingthemcertainstationsanywayjustincase. Butit’saquestionthepublickeepsaskingwhilethegovernmentismakingpreparationsforthenextflupandemic大流行.SotheCentersforDiseaseControlandPreventionCDCcameupwithpreliminaryguidelines.Wedon’twantPeoplewearingthemeverywheresaidtheCDC.Theoverallrecommendationreallyistoavoidexposure. Whenthatisnotpossibletheguidelinessayyoushouldconsiderwearingasimplesurgicalmaskifyouareinoneofthethreefollowingsituations.Firstyou’rehealthyandcan’tavoidgoingtoacrowdedplace.Secondyou’resickandthinkyoumayhaveclosecontactwiththehealthysuchasafamilymembercheckingonyou.Thirdyoulivewithsomeonewho’ssickandthusmightbeintheearlystagesofinfectionbutstillneedtogoout. Influenzapandemicscanstrikewhentheeasy-to-mutate变异fluvirusshiftstoastrain菌株thatpeopleneverhaveexperienced.ScientistscannotpredictwhenthenextpandemicwillarrivealthoughconcernisrisingthattheAsianbirdflumighttriggeroneifitstartsspreadingeasilyfrompersontoperson. Duringtheflupandemicyoushouldprotectyourself.Avoidcrowdsandavoidclosecontactwiththesickunlessyoumustcareforsomeone.Whyaren’tmasksaddedtothisself-protectionlist?Becausetheycanhelptrapvirus-ladendropletsflyingthroughtheairwithacoughorsneeze.Simplesurgicalmasksonlyfilterthelargerdroplets飞沫.BesidestheCDCisafraidmasksmaycreateafalsesenseofsecurity.Perhapssomeonewhoshouldhavestayedhomewoulddon戴anill-fittingmaskandhoponthesubwayinstead. Nordoesfluonlyspreadthroughtheair.Saysomeonecoversasneezewithhisorherhandthentouchesadoorknoborsubwaypole.Ifyoutouchthatspotnextandthenputgermyhandsonyournoseormouthyou’vebeenexposed.It’shardertorubyournosewhilewearingamasksoyourfacemaygetprettysweatyundermasks.Youreachundertowipethatsweatandmaytransfergermscaughtontheoutsideofthemaskstraighttothenose.Thesearetheproblemsfacemasksmaycreatefortheirusers. Whetherpeopleshouldorshouldnotusefacemasksstillremainsaquestion.Thegeneralpublichastowaitpatientlyfortheresultsofthemaskresearchscientistsarestilldoing. TheCDCsuggeststhatpeople
LackofOxygenDelayedtheRiseofAnimalsonEarth Scientistshavelongspeculatedastowhyanimalspeciesdidn’tflourishsooneroncesufficientoxygencoveredtheEarth’ssurface.AnimalsbegantoprosperattheendoftheProterozoicperiodabout800millionyearsago—butwhataboutthebillion-yearstretchbeforethatwhenmostresearchersthinktherealsowasplentyofoxygen? Wellitseemstheairwasn’tsogreatthenafterall. InastudypublishedOct.31inScienceYaleresearcherNoahPlanavskyandhiscolleaguesfoundthatoxygenlevelsduringtheboringbillionperiodwereonly0.1%ofwhattheyaretoday.InotherwordsEarth’satmospherecouldn’thavesupportedadiversityofcreaturesnomatterwhatgeneticadvancementswerepoisedtooccur. ThereisnoquestionthatgeneticandecologicalinnovationmustultimatelybebehindtheriseofanimalsbutitisequallyunavoidablethatanimalsneedacertainlevelofoxygensaidPlanavskyco-leadauthoroftheresearchalongwithChristopherReinhardoftheGeorgiaInstituteofTechnology.We’reprovidingthefirstevidencethatoxygenlevelswerelowenoughduringthisperiodtopotentiallypreventtheriseofanimals. ThescientistsfoundtheirevidencebyanalyzingchromiumCrisotopesinancientsedimentsfromChinaAustraliaCanadaandtheUnitedStates.ChromiumisfoundintheEarth’scontinentalcrustandchromiumoxidationisdirectlylinkedtothepresenceoffreeoxygenintheatmosphere. Specificallytheteamstudiedsamplesdepositedinshallowiron-richoceanareasneartheshore.Theycomparedtheirdatawithothersamplestakenfromyoungerlocalesknowntohavehigherlevelsofoxygen. Oxygen’sroleincontrollingthefirstappearanceofanimalshaslongvexedscientists.WeweremissingtherightapproachuntilnowPlanavskysaid.Chromiumgaveustheproxy.Previousestimatesputtheoxygenlevelat40%oftoday’sconditionsduringpre-animaltimesleavingopenthepossibilitythatoxygenwasalreadyplentifulenoughtosupportanimallife. Inthenewstudytheresearchersacknowledgedthatoxygenlevelswerehighlydynamicintheearlyatmospherewiththepotentialforoccasionalspikes.HowevertheysaidItseemsclearthatthereisafirst-orderdifferenceinthenatureofEarthsurfaceCrcyclingbeforeandaftertheriseofanimals. Ifwearerightourresultswillreallychangehowpeopleviewtheoriginsofanimalsandothercomplexlifeandtheirrelationshipstotheco-evolvingenvironmentsaidco-authorTimLyonsoftheUniversityofCalifornia-Riverside.Thiscouldbeagamechanger. There’salotofinterestrightnowinabroaderdiscussionsurroundingtherolethatenvironmentalstabilityplayedintheevolutionofcomplexlifeandwethinkourresultsareasignificantcontributiontothatReinhardsaid.ThestudydiscoveredtheriseofanimalsoccurredearlierthantheProterozoicperiod.
What’skillingtheBats Firstitwasbees.Nowitisbats.BiologistsinAmericaareworkinghardtodiscoverthecauseofthemysteriousdeathsoftensofthousandsofbatsinthenortheasternpartofthecountry.MostofthebatsaffectedarethecommonlittlebrownbatsMyotislucifugusbutotherspeciessuchasthelong-earedbatthesmall-footedhattheeasternpipistrelleandtheIndianabathavealsobeenaffected.Insomecavesmorethan90percentofthebatpopulationshavedied. Onepossibilityisdisease.Awhitefungus真菌knownasfusariumhasbeenfoundonthenosesofbothlivinganddeadbats.Howeverscientistsdon’tknowIfthefungusistheprimarycauseofdeathasecondarycauseofdeathornotacauseatallbuttheresultofsomeotherconditions. Anotherpossiblecauseisalackoffood.Forexamplebatstypicallyeatalargenumberofmoths蛾andinsomestatessuchasNewYorkthenumberofmothshasbeendeclininginrecentyears.Ifbatscan’teatenoughfoodtheystarvetodeath. Stillotherscientistsbelievethatglobalwarmingistoblame.Warmertemperaturesinrecentyearshavebeenwakinguphibernating冬眠batsearlierthanusual.Ifbatsbreaktheirhibernationatthewrongtimetheymightnotfindtheirexpectedfoodsources.Theweathermightalsoturncoldagainandweakenorkillthebats. Scientistsmightnotagreeonthecausesofthebatdie-offbuttheydoagreeontheconsequences.Batsareanimportantpredatorofmosquitoes;asinglebrownbatcaneat1000ormoreinsectsinanhour.Theyalsoeatbeetlesandotherinsectsthatdamageplantcrops.Iftherearen’tenoughbatsdamagewillbegreatfromtheinsectstheyeatWhilebatslivealongtimefortheirsize－thelittlebrownbatcanliveformorethan30years－afemalebathasonlyonebabyperyearsobatpopulationsgrowslowly.ManybatspeciesintheUnitedStatesarealreadyprotectedorendangered. Howcanyouhelp?Donotdisturbsleepingornestingbats.IfyoudiscoverbatethatseemtobesickorthataredeadcontactyourlocalFish＆WildlifeDepartmentwiththedetails.Howeverbecarefulnottotouchtheanimals. Whatisthemainideaofthispassage?
TheStockExchangeisin{{U}}turmoil{{/U}}followingahugewaveofselling.
What’skillingtheBats Firstitwasbees.Nowitisbats.BiologistsinAmericaareworkinghardtodiscoverthecauseofthemysteriousdeathsoftensofthousandsofbatsinthenortheasternpartofthecountry.MostofthebatsaffectedarethecommonlittlebrownbatsMyotislucifugusbutotherspeciessuchasthelong-earedbatthesmall-footedhattheeasternpipistrelleandtheIndianabathavealsobeenaffected.Insomecavesmorethan90percentofthebatpopulationshavedied. Onepossibilityisdisease.Awhitefungus真菌knownasfusariumhasbeenfoundonthenosesofbothlivinganddeadbats.Howeverscientistsdon’tknowIfthefungusistheprimarycauseofdeathasecondarycauseofdeathornotacauseatallbuttheresultofsomeotherconditions. Anotherpossiblecauseisalackoffood.Forexamplebatstypicallyeatalargenumberofmoths蛾andinsomestatessuchasNewYorkthenumberofmothshasbeendeclininginrecentyears.Ifbatscan’teatenoughfoodtheystarvetodeath. Stillotherscientistsbelievethatglobalwarmingistoblame.Warmertemperaturesinrecentyearshavebeenwakinguphibernating冬眠batsearlierthanusual.Ifbatsbreaktheirhibernationatthewrongtimetheymightnotfindtheirexpectedfoodsources.Theweathermightalsoturncoldagainandweakenorkillthebats. Scientistsmightnotagreeonthecausesofthebatdie-offbuttheydoagreeontheconsequences.Batsareanimportantpredatorofmosquitoes;asinglebrownbatcaneat1000ormoreinsectsinanhour.Theyalsoeatbeetlesandotherinsectsthatdamageplantcrops.Iftherearen’tenoughbatsdamagewillbegreatfromtheinsectstheyeatWhilebatslivealongtimefortheirsize－thelittlebrownbatcanliveformorethan30years－afemalebathasonlyonebabyperyearsobatpopulationsgrowslowly.ManybatspeciesintheUnitedStatesarealreadyprotectedorendangered. Howcanyouhelp?Donotdisturbsleepingornestingbats.IfyoudiscoverbatethatseemtobesickorthataredeadcontactyourlocalFish＆WildlifeDepartmentwiththedetails.Howeverbecarefulnottotouchtheanimals. Whatisthepurposeofthelastparagraph?
I’llBeBach ComposerDavidCopeistheinventorofacomputerprogramthatwritesoriginalworksofclassicalmusic.IttookCope30yearstodevelopthesoftware.Nowmostpeoplecan’t_____51thedifferencebetweenmusicbythefamousGermancomposerJ.S.Bach1685-1750andtheBach-likecompositionsfromCope’scomputer. Itallstartedin1980intheUnitedStateswhenCopewastryingtowriteanopera.Hewashaving_____52thinkingofnewmelodiessohewroteacomputerprogramtocreatethemelodies.Atfirstthismusicwasnot_____53tolistento.WhatdidCopedo?Hebegantorethinkhowhumanbeingscomposemusic.Herealizedthatcomposersbrains_____54likebigdatabases.Firsttheytakeinallthemusicthattheyhaveeverheard.Thentheytake_____55themusicthattheydislike.Finallytheymakenewmusicfromwhatis_____56.AccordingtoCopeonlythegreatcomposersareabletocreatethedatabaseaccuratelyrememberitandformnewmusicalpatternsfromit. Copebuilta_____57databaseofexistingmusic.HebeganwithhundredsofworksbyBach.Thesoftwareanalyzedthedataa_____58itdownintosmallerpiecesandlookedforpatterns.Itthencombinedthe_____59intonewpatterns.BeforelongtheprogramcouldcomposeshortBach-likeworks.Theyweren’tgoodbutitwasastart. Copeknewhehadmoreworktodo-hehadawholeoperatowrite.Hecontinuedtoimprovethesoftware.Soonitcould_____60morecomplexmusic.Healsoaddedmanyothercomposersincludinghisownworktothedatabase. AfewyearslaterCope’scomputerprogramcalledEmmywasreadytohelphimwithhisopera.The_____61requiredalotofcollaborationbetweenthecomposerandEmmy.Copelistenedtothecomputer’smusicalideasandusedthe_____62thatheliked.WithEmmytheoperatookonlytwoweekstofinish.ItwascalledCradleFallinganditwasagreat_____63!Copereceivedsomeofthebestreviewsofhiscareerbutnooneknewexactly_____64hehadcomposedthework. SincethatfirstoperaEmmyhaswrittenthousandsofcompositions.CopestillgivesEmmyfeedbackonwhathelikesanddoesn’tlikeofhermusic_____65sheisdoingmostofthehardworkofcomposingthesedays!
Welivedforyearsina{{U}}perpetual{{/U}}stateoffear
FirstImage-recognitionSoftware1.DartmouthresearchersandtheircolleagueshavecreatedanartificialintelligencesoftwarethatusesphotostolocatedocumentsontheInternetwithfargreateraccuracythaneverbefore.2.Thenewsystemwhichwastestedonphotosandisnowbeingappliedtovideosshowsforthefirsttimethatamachinelearningalgorithm运算法则forimagerecognitionandretrievalisaccurateandefficientenoughtoimprovelarge-scaledocumentsearchesonline.Thesystemusespixel像素datainimagesandpotentiallyvideo—ratherthanjusttext—tolocatedocuments.Itlearnstorecognizethepixelsassociatedwithasearchphrasebystudyingtheresultsfromtext-basedimagesearchengines.Theknowledgegleaned收集fromthoseresultscanthenbeappliedtootherphotoswithouttagsorcaptions图片说明makingformoreaccuratedocumentsearchresults.3."Overthelast30years"saysAssociateProfessorLorenzoTorresaniaco-authorofthestudy"theWebhasevolvedfromasmallcollectionofmostlytextdocumentstoamodernmassivefast-growingmultimediadatasetwherenearlyeverypageincludesmultiplepicturesorvideos.WhenapersonlooksataWebpageheimmediatelygetsthegist主旨ofitbylookingatthepicturesinit.YetsurprisinglyallexistingpopularsearchenginessuchasGoogleorBingstripawaytheinformationcontainedinthephotosanduseexclusivelythetextofWebpagestoperformthedocumentretrieval.Ourstudyisthefirsttoshowthatmodernmachinevisionsystemsareaccurateandefficientenoughtomakeeffectiveuseoftheinformationcontainedinimagepixelstoimprovedocumentsearch."4.Theresearchersdesignedandtestedamachinevisionsystem—atypeofartificialintelligencethatallowscomputerstolearnwithoutbeingexplicitlyprogrammed—thatextractssemantic语义的informationfromthepixelsofphotosinWebpages.ThisinformationisusedtoenrichthedescriptionoftheHTMLpageusedbysearchenginesfordocumentretrieval.Theresearcherstestedtheirapproachusingmorethan600searchqueries查询onadatabaseof50millionWebpages.Theyselectedthetext-retrievalsearchenginewiththebestperformanceandmodifiedittomakeuseoftheadditionalsemanticinformationextractedbytheirmethodfromthepicturesoftheWebpages.Theyfoundthatthisproduceda30percentimprovementinprecisionovertheoriginalsearchenginepurelybasedontext. Paragraph4
LackofOxygenDelayedtheRiseofAnimalsonEarth Scientistshavelongspeculatedastowhyanimalspeciesdidn’tflourishsooneroncesufficientoxygencoveredtheEarth’ssurface.AnimalsbegantoprosperattheendoftheProterozoicperiodabout800millionyearsago—butwhataboutthebillion-yearstretchbeforethatwhenmostresearchersthinktherealsowasplentyofoxygen? Wellitseemstheairwasn’tsogreatthenafterall. InastudypublishedOct.31inScienceYaleresearcherNoahPlanavskyandhiscolleaguesfoundthatoxygenlevelsduringtheboringbillionperiodwereonly0.1%ofwhattheyaretoday.InotherwordsEarth’satmospherecouldn’thavesupportedadiversityofcreaturesnomatterwhatgeneticadvancementswerepoisedtooccur. ThereisnoquestionthatgeneticandecologicalinnovationmustultimatelybebehindtheriseofanimalsbutitisequallyunavoidablethatanimalsneedacertainlevelofoxygensaidPlanavskyco-leadauthoroftheresearchalongwithChristopherReinhardoftheGeorgiaInstituteofTechnology.We’reprovidingthefirstevidencethatoxygenlevelswerelowenoughduringthisperiodtopotentiallypreventtheriseofanimals. ThescientistsfoundtheirevidencebyanalyzingchromiumCrisotopesinancientsedimentsfromChinaAustraliaCanadaandtheUnitedStates.ChromiumisfoundintheEarth’scontinentalcrustandchromiumoxidationisdirectlylinkedtothepresenceoffreeoxygenintheatmosphere. Specificallytheteamstudiedsamplesdepositedinshallowiron-richoceanareasneartheshore.Theycomparedtheirdatawithothersamplestakenfromyoungerlocalesknowntohavehigherlevelsofoxygen. Oxygen’sroleincontrollingthefirstappearanceofanimalshaslongvexedscientists.WeweremissingtherightapproachuntilnowPlanavskysaid.Chromiumgaveustheproxy.Previousestimatesputtheoxygenlevelat40%oftoday’sconditionsduringpre-animaltimesleavingopenthepossibilitythatoxygenwasalreadyplentifulenoughtosupportanimallife. Inthenewstudytheresearchersacknowledgedthatoxygenlevelswerehighlydynamicintheearlyatmospherewiththepotentialforoccasionalspikes.HowevertheysaidItseemsclearthatthereisafirst-orderdifferenceinthenatureofEarthsurfaceCrcyclingbeforeandaftertheriseofanimals. Ifwearerightourresultswillreallychangehowpeopleviewtheoriginsofanimalsandothercomplexlifeandtheirrelationshipstotheco-evolvingenvironmentsaidco-authorTimLyonsoftheUniversityofCalifornia-Riverside.Thiscouldbeagamechanger. There’salotofinterestrightnowinabroaderdiscussionsurroundingtherolethatenvironmentalstabilityplayedintheevolutionofcomplexlifeandwethinkourresultsareasignificantcontributiontothatReinhardsaid.Thesamplesstudiedintheresearchwerecollectedinoceanareas.
热门题库
更多
卫生类
综合类
国际货运代理师
报关水平测试
报检员
物流员(四级)
助理物流师(三级)
物流师(二级)
高级物流师(一级)
物流案例分析
单证员基础理论与知识
单证员缮制与操作
国际货运代理理论与实务
外贸综合业务
外贸外语
跟单员基础理论
湘公网安备 43130202000226号