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Roguetheoryofsmellgetsaboost
1.Acontroversialtheoryofhowwesmell,whichclaimsthatourfinesenseofodourdependsonquantummechanics,hasbeengiventhethumbsupbyateamofphysicists.
2.CalculationsbyresearchersatUniversityCollegeLondon(UCL)showthattheideathatwesmellodourmoleculesbysensingtheirmolecularvibrationsmakessenseintermsofthephysicsinvolved.
3.That'sstillsomewayfromprovingthatthetheory,proposedinthemid-1990sbybiophysicistLucaTurin,iscorrect.Butitshouldmakeotherscientiststaketheideamoreseriously.
4."Thisisabigstepforward,"saysTurin,whohasnowsetuphisownperfumecompanyFlexitralinVirginia.Hesaysthatsincehepublishedhistheory,"ithasbeenignoredratherthancriticized."
5.Mostscientistshaveassumedthatoursenseofsmelldependsonreceptorsinthenosedetectingtheshapeofincomingmolecules,whichtriggersasignaltothebrain.Thismolecular'lockandkey'processisthoughttoliebehindawiderangeofthebody'sdetectionsystems:itishowsomepartsoftheimmunesystemrecogniseinvaders,forexample,andhowthetonguerecognizessometastes.
6.ButTurinarguedthatsmelldoesn'tseemtofitthispictureverywell.Moleculesthatlookalmostidenticalcansmellverydifferent—suchasalcohols,whichsmelllikespirits,andthiols,whichsmelllikerotteneggs.Andmoleculeswithverydifferentstructurescansmellsimilar.Moststrikingly,somemoleculescansmelldifferent—toanimals,ifnotnecessarilytohumans—simplybecausetheycontaindifferentisotopes(atomsthatarechemicallyidenticalbuthaveadifferentmass).
7.Turin'sexplanationforthesesmellyfactsinvokestheideathatthesmellsignalinolfactoryreceptorproteinsistriggerednotbyanodourmolecule'sshape,butbyitsvibrations,whichcanenourageanelectrontojumpbetweentwopartsofthereceptorinaquantum-mechanicalprocesscalledtunnelling.Thiselectronmovementcouldinitiatethesmellsignalbeingsenttothebrain.
8.Thiswouldexplainwhyisotopescansmelldifferent:theirvibrationfrequenciesarechangediftheatomsareheavier.Turin'smechanism,saysMarshallStonehamoftheUCLteam,ismorelikeswipe-cardidentificationthanakeyfittingalock.
9.Vibration-assistedelectrontunnellingcanundoubtedlyoccur—itisusedinanexperimentaltechniqueformeasuringmolecularvibrations."Thequestioniswhetherthisispossibleinthenose,"saysStoneham'scolleague,AndrewHorsfield.
10.StonehamsaysthatwhenhefirstheardaboutTurin'sidea,whileTurinwashimselfbasedatUCL,"Ididn'tbelieveit".But,headds,"becauseitwasaninterestingidea,IthoughtIshouldproveitcouldn'twork.Ididsomesimplecalculations,andonlythenbegantofeelLucacouldberight."NowStonehamandhisco-workershavedonethejobmorethoroughly,inapapersoontobepublishedinPhysicalReviewLetters.
11.TheUCLteamcalculatedtheratesofelectronhoppinginanosereceptorthathasanodorantmoleculeboundtoit.Thisratedependsonvariouspropertiesofthebiomolecularsystemthatarenotknown,buttheresearcherscouldestimatetheseparametersbasedontypicalvaluesformoleculesofthissort.
12.Thekeyissueiswhetherthehoppingratewiththeodorantinplaceissignificantlygreaterthanthatwithoutit.Thecalculationsshowthatitis—whichmeansthatodouridentificationinthiswayseemstheoreticallypossible.
13.ButHorsfieldstressesthatthat'sdifferentfromaproofofTurin'sidea."Sofarthingslookplausible,butweneedproperexperimentalverification.We'rebeginningtothinkaboutwhatexperimentscouldbeperformed."
14.Meanwhile,Turinispressingaheadwithhishypothesis."AtFlexitralwehavebeendesigningodorantsexclusivelyonthebasisoftheircomputedvibrations,"hesays."Oursuccessrateatodorantdiscoveryistwoordersofmagnitudebetterthanthecompetition."Attheveryleast,heisputtinghismoneywherehisnoseis.
Questions5-9
Completethesentencesbelowwithwordsfromthepassage.UseNOMORETHANTHREEWORDSforeachanswer.
5.Thehypothesisthatwesmellbysensingthemolecularvibrationwasmadeby______.
6.Turin'scompanyisbasedin______.
7.Mostscientistsbelievedthatournoseworksinthesamewayasour______.
8.Differentisotopescansmelldifferentwhen______weighdifferently.
9.AccordingtoAudrewHorsfield,itisstilltobeprovedthat______couldreallyoccurinhumannose.
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Passage3
Questions11to15arebasedonthefollowingpassage:
“...WearenotabouttoentertheInformationAgebutinsteadareratherwellintoit.”Presentpredictionsarethatby1990,aboutthirtymillionjobsintheUnitedStates,oraboutthirtypercentofthejobmarket,willbecomputer-related.In1980,onlytwenty-onepercentofallUnitedStateshighschoolsownedoneormorecomputersforstudentuse.(79)Inthefallof1985,anewsurveyrevealedthathalfofUnitedStatessecondaryschoolshavefifteenormorecomputersforstudentuse.Andnoweducationalexperts,administrators,andeventhegeneralpublicaredemandingthatallstudentsbecome“computerliterate(慢點…的).”“Bytheyear2000knowledgeofcomputerswillbenecessaryinovereightypercentofalloccupations.Soonthosepeoplenoteducatedincomputerusewillbecomparedtothosewhoareprintilliteratetoday.”
Whatis“computerliteracy”?Thetermitselfseemstoimplysoonextentof“knowing”aboutcomputers,butknowingwhat.Thecurrentopinionseemstobethatthisshouldincludeageneralknowledgeofwhatcomputersare,plusalittleoftheirhistoryandsomethingofhowtheyoperate.
Therefore,itisvitalthateducatorseverywheretakeacarefullooknotonlyatwhatisbeingdone,butalsoatwhatshouldbedoneinthefieldofcomputereducation.Todaymostadultsarecapableofutilisingamotorvehiclewithouttheslightestknowledgeofhowtheinternal-combustionengineworks.Weeffectivelyusealltypesofelectricalequipmentwithoutbeingabletotelltheirhistoriesortoexplainhowtheywork.(80)Businesspeopleforyearshavemadegooduseoftypewritersandaddingmachines,yetfewhaveeverknownhowtorepairthem.Why,then,attempttoteachcomputersbyteachinghoworwhytheywork?
Rather,wefirstmustconcentrateonteachingtheeffectiveuseofthecomputerasthetoolis.
“Knowinghowtouseacomputeriswhat’sgoingtobeimportant,wedon’ttalkabout‘a(chǎn)utomobileliteracy.‘Wejustgetinourcarsanddrivethem.”
11.In1990,thenumberofjobshavingnothingtodowithcomputersintheUnitedStateswillbereducedto________.
A)79millionB)30millionC)70millionD)100million(C)
12.Theexpression“Printilliterate”(Para.1,Line16)refersto________.
A)onewhohasneverlearntprintingB)onewhoisnotcomputerliterate
C)onewhohasneverlearnttoreadD)onewhoisnotabletouseatypewriter(C)
13.Thefirstparagraphismainlyabout________.
A)recentpredictionsofcomputer-relatedjobsB)thewideuseofcomputersinschools
C)theurgencyofcomputereducationD)publicinterestincomputers(C)
14.Accordingtotheauthor,theeffectivewaytospreadtheuseofcomputersistoteach____.
A)whatcomputersareB)howtousecomputers
C)wherecomputerscanbeusedD)howcomputerswork(B)
15.WhichofthefollowingstatementsisFALSE?
A)Whattoteachaboutcomputersshouldbereconsidered.
B)Thosewhoarenoteducatedincomputerusewillfinditdifficulttogetajob.
C)HumansocietyhasalreadyenteredtheInformationAge.
D)Thosewhowanttousecomputersshouldknowhowcomputersoperate.
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