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.
5.Luca Turin
6.Virginia
7.tongue
8.the atoms
9.vibration-assisted electron tunneling
暂无解析
FelicityLawrence
ThursdayDecember28,2006
TheGuardian
1.ConsumersaretobepresentedwithtworivalnewyearadvertisingcampaignsastheFoodStandardsAgencygoespublicinitsbattlewiththeindustryoverthelabellingofunhealthyfoods.
2.TheGuardianhaslearnedthattheFSAwilllaunchaseriesof10-secondtelevisionadvertsinJanuarytellingshoppershowtofollowared,amberandgreentrafficlightlabellingsystemonthefrontoffoodpacks,whichisdesignedtotackleBritain’sobesityepidemic.
3.Thecampaignisadirectresponsetoaconcertedattemptbyleadingfoodmanufacturersandretailers,includingKellogg’sandTesco,toderailthesystem.Theindustryfearsthattrafficlightswoulddemoniseentirecategoriesoffoodsandcouldseriouslydamagethemarketforthosethatarefatty,saltyorhighinsugar.
4.TheUKmarketforbreakfastcerealsisworth￡1.27bnayearandthemanufacturersfearitwillbeseverelydentedifredlightlabelsareputonpackagingdrawingattentiontothefactthatthemajorityarehighinsaltand/orsugar.
5.Theindustryisplanningamajormarketingcampaignforacompetinglabellingsystemwhichavoidscolour-codinginfavourofinformationaboutthepercentageof"guidelinedailyamounts"(GDAs)offat,saltandsugarcontainedintheirproducts.
6.Thebattleforthenation’sdietcomesasnewrulesontelevisionadvertisingcomeintoforceinJanuarywhichwillbaradvertsforunhealthyfoodsfromcommercialbreaksduringprogrammesaimedatchildren.SourcesattheTVregulatorsarebracedforalegalchallengefromtheindustryandhavedescribedthelobbyingeffortstoblockanynewadbanorcolour-codedlabellingas"themostferociouswe’veeverexperienced".
7.Ofcom’schiefexecutive,EdRichards,said:"Wearepreparedtofaceuptoanylegalactionfromtheindustry,butweverymuchhopeitwillnotbenecessary."TheFSAsaiditwasexpectinganonslaughtfromtheindustryinJanuary.SeniorFSAofficialssaidthemanufacturers’effortstoundermineitsproposalsonlabellingcouldthreatentheagency’scredibility.
8.TerrenceCollis,FSAdirectorofcommunications,dismissedclaimsthattheproposalswerenotbasedonscience."WehavesomeofthemostrespectedscientistsinEurope,bothwithintheFSAandinourindependentadvisorycommittees.ItisunjustifiedandnonsensicaltoattacktheFSA’sscientificreputationandtotrytoundermineitscredibility."
9.TheFSAisunderstoodtohavebriefeditsadagency,United,beforeChristmas,andwillaimtoairadsthatare"non-confrontational,humorousandfactual"asacounterweighttoindustry’seffortsaboutthesametime.Theagency,however,willhaveatinyfractionofthebudgetavailabletotheindustry.
10.GavinNeath,chairmanofUnileverUKandpresidentoftheFoodandDrinkFederation,hassaidthattheindustryhasmadeenormousprogressbutcouldnotacceptred"stop"signsonitsfood.
11.AlastairSykes,chiefexecutiveofNestléUK,saidthatundertheFSAproposalsallhiscompany’sconfectioneryandmostofitscerealswouldscoreared."Arewesayingpeopleshouldn’teatconfectionery?We’redrivenbyconsumersandwhattheywant,andmuchofwhatwedohasbeentomakeourproductshealthier,"hesaid.
12.ChrisWermann,directorofcommunicationsatKellogg’s,said:"Inprinciplewecouldneveraccepttrafficlightlabelling."
13.TherivallabellingschemeintroducedbyKellogg’s,Danone,Unilever,Nestlé,KraftandTescoandnowfavouredby21manufacturers,usesanindustry-devisedsystembasedonidentifyingGDAsofkeynutrients.TescosaysithastestedbothtrafficlightsandGDAlabelsinitsstoresandthatthelatterincreasedsalesofhealthierfoods.
14.ButtheFSAsaiditcouldnotlivewiththisGDAsystemalonebecauseitwas"notscientific"oreasyforshopperstounderstandataglance.
Questions1-6
AnswerthequestionsbelowusingNOMORETHANTHREEWORDSfromthepassageforeachanswer.
1.Whenwillinstructionsbegivenonreadingthecolor-codedlabels?
2.Wherecancustomersfindtheredlightlabels?
3.WhatproblemistheFSAtryingtohandlewiththelabelingsystem?
4.Whichproductsellswellbutmaynotbehealthy?
5.Whatinformation,accordingtothemanufacturers,canbelabeledonproducts?
6.Whatcannotbeadvertisedduringchildren’sprogrammes?
Questions7-13
Usetheinformationinthetexttomatchthepeople(listedA-E)withtheopinions(listed7-13)below.Writetheappropriateletter(A-E)forquestions1-7.
NBYoumayuseanylettermorethanonce.
AEdRichard
BTerrenceCollis
CGavinNeath
DAlastairSykes
EChrisWermann
7.Generallywewillnotagreetousetheredlightlabels.
8.ItisunreasonabletodoubtifFSAistrustworthy.
9.Wearetryingtomeetourconsumers’needs.
10.Thefoodindustryhasbeenimprovinggreatly.
11.Thecolor-codedlabelingsystemisscientific.
12.OurproductswillbelabeledunhealthybytheFSA.
13.Wearereadytoconfrontthemanufacturers.
-----Dad，lookatthebuilding.Itisonfire.
-----Call119____________mobilephonerightnow
-----AheavysnowhitmostofthepartsofChinainJanuary,2008.
-----____________terriblenews!
Isthere______________totellus?No,nothing.
1There'sadimmerswitchinsidethesunthatcausesitsbrightnesstoriseandfallontimescalesofaround100,000years-exactlythesameperiodasbetweeniceagesonEarth.Sosaysaphysicistwhohascreatedacomputermodelofourstar'score.
2RobertEhrlichofGeorgeMasonUniversityinFairfax,Virginia,modelledtheeffectoftemperaturefluctuationsinthesun'sinterior.Accordingtothestandardview,thetemperatureofthesun'scoreisheldconstantbytheopposingpressuresofgravityandnuclearfusion.However,Ehrlichbelievedthatslightvariationsshouldbepossible.
3HetookashisstartingpointtheworkofAttilaGrandpierreoftheKonkolyObservatoryoftheHungarianAcademyofSciences.In2005,Grandpierreandacollaborator,Gáborágoston,calculatedthatmagneticfieldsinthesun'scorecouldproducesmallinstabilitiesinthesolarplasma.Theseinstabilitieswouldinducelocalisedoscillationsintemperature.
4Ehrlich'smodelshowsthatwhilstmostoftheseoscillationscanceleachotherout,somereinforceoneanotherandbecomelong-livedtemperaturevariations.Thefavouredfrequenciesallowthesun'scoretemperaturetooscillatearounditsaveragetemperatureof13.6millionkelvinincycleslastingeither100,000or41,000years.Ehrlichsaysthatrandominteractionswithinthesun'smagneticfieldcouldflipthefluctuationsfromonecyclelengthtotheother.
5ThesetwotimescalesareinstantlyrecognisabletoanyonefamiliarwithEarth'siceages:forthepastmillionyears,iceageshaveoccurredroughlyevery100,000years.Beforethat,theyoccurredroughlyevery41,000years.
6MostscientistsbelievethattheiceagesaretheresultofsubtlechangesinEarth'sorbit,knownastheMilankovitchcycles.OnesuchcycledescribesthewayEarth'sorbitgraduallychangesshapefromacircletoaslightellipseandbackagainroughlyevery100,000years.ThetheorysaysthisalterstheamountofsolarradiationthatEarthreceives,triggeringtheiceages.However,apersistentproblemwiththistheoryhasbeenitsinabilitytoexplainwhytheiceageschangedfrequencyamillionyearsago.
7"InMilankovitch,thereiscertainlynogoodideawhythefrequencyshouldchangefromonetoanother,"saysNeilEdwards,aclimatologistattheOpenUniversityinMiltonKeynes,UK.NoristhetransitionproblemtheonlyonetheMilankovitchtheoryfaces.EhrlichandothercriticsclaimthatthetemperaturevariationscausedbyMilankovitchcyclesaresimplynotbigenoughtodriveiceages.
8However,EdwardsbelievesthesmallchangesinsolarheatingproducedbyMilankovitchcyclesarethenamplifiedbyfeedbackmechanismsonEarth.Forexample,ifseaicebeginstoformbecauseofaslightcooling,carbondioxidethatwouldotherwisehavefounditswayintotheatmosphereaspartofthecarboncycleislockedintotheice.ThatweakensthegreenhouseeffectandEarthgrowsevencolder.
9AccordingtoEdwards,thereisnolackofsuchmechanisms."Ifyouaddtheireffectstogether,thereismorethanenoughfeedbacktomakeMilankovitchwork,"hesays."Theproblemnowisidentifyingwhichmechanismsareatwork."ThisiswhyscientistslikeEdwardsarenotyetreadytogiveuponthecurrenttheory."Milankovitchcyclesgiveusiceagesroughlywhenweobservethemtohappen.Wecancalculatewhereweareinthecycleandcompareitwithobservation,"hesays."Ican'tseeanywayoftesting[Ehrlich's]ideatoseewhereweareinthetemperatureoscillation."
10Ehrlichconcedesthis."Ifthereisawaytotestthistheoryonthesun,Ican'tthinkofonethatispractical,"hesays.That'sbecausevariationover41,000to100,000yearsistoogradualtobeobserved.However,theremaybeawaytotestitinotherstars:reddwarfs.Theircoresaremuchsmallerthanthatofthesun,andsoEhrlichbelievesthattheoscillationperiodscouldbeshortenoughtobeobserved.Hehasyettocalculatethepreciseperiodortheextentofvariationinbrightnesstobeexpected.
11NigelWeiss,asolarphysicistattheUniversityofCambridge,isfarfromconvinced.HedescribesEhrlich'sclaimsas"utterlyimplausible".EhrlichcountersthatWeiss'sopinionisbasedonthestandardsolarmodel,whichfailstotakeintoaccountthemagneticinstabilitiesthatcausethetemperaturefluctuations.
Questions1-4
CompleteeachofthefollowingstatementswithOneorTwonamesofthescientistsfromtheboxbelow.
WritetheappropriatelettersA-Einboxes1-4onyouranswersheet.
A.AttilaGrandpierre
B.Gáborágoston
C.NeilEdwards
D.NigelWeiss
E.RobertEhrlich
1....claimsthereadimmerswitchinsidethesunthatcausesitsbrightnesstoriseandfallinperiodsaslongasthosebetweeniceagesonEarth.
2....calculatedthattheinternalsolarmagneticfieldscouldproduceinstabilitiesinthesolarplasma.
3....holdsthatMilankovitchcyclescaninducechangesinsolarheatingonEarthandthechangesareamplifiedonEarth.
4....doesn'tbelieveinEhrlich'sviewpointsatall.
Questions5-9
Dothefollowingstatementsagreewiththeinformationgiveninthereadingpassage?
Inboxes5-9onyouranswersheetwrite
TRUEifthestatementistrueaccordingtothepassage
FALSEifthestatementisfalseaccordingtothepassage
NOTGIVENiftheinformationisnotgiveninthepassage
5.Theiceageschangedfrequencyfrom100,000to41,000yearsamillionyearsago.
6.ThesoleproblemthattheMilankovitchtheorycannotsolveistoexplainwhytheiceagefrequencyshouldshiftfromonetoanother.
7.Carbondioxidecanbelockedartificiallyintoseaicetoeliminatethegreenhouseeffect.
8.SomescientistsarenotreadytogiveuptheMilankovitchtheorythoughtheyhaven'tfiguredoutwhichmechanismsamplifythechangesinsolarheating.
9.BothEdwardsandEhrlichbelievethatthereisnopracticalwaytotestwhenthesolartemperatureoscillationbeginsandwhenends.
Questions10-14
Completethenotesbelow.
ChooseonesuitablewordfromtheReadingPassageaboveforeachanswer.
Writeyouranswersinboxes10-14onyouranswersheet.
Thestandardviewassumesthattheopposingpressuresofgravityandnuclearfusionsholdthetemperature...10...inthesun'sinterior,buttheslightchangesintheearth's...11...alterthetemperatureontheearthandcauseiceagesevery100,000years.ABritishscientist,however,challengesthisviewbyclaimingthattheinternalsolarmagnetic...12...caninducethetemperatureoscillationsinthesun'sinterior.Thesun'scoretemperatureoscillatesarounditsaveragetemperaturein...13...lastingeither100,000or41,000years.Andthe...14...interactionswithinthesun'smagneticfieldcouldflipthefluctuationsfromonecyclelengthtotheother,whichexplainswhytheiceageschangedfrequencyamillionyearsago.