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.
1. E
See the sentences in paragraph 1(There's a dimmer switch inside the sun that causes its brightness to rise and fall on timescales of around 100,000 years - exactly the same period as between ice ages on Earth. So says a physicist who has created a computer model of our star's core.) and para.2 (Robert Ehrlich of George Mason University in Fairfax, Virginia, modelled the effect of temperature fluctuations in the sun's interior.)
2. A B
See para.3: Grandpierre and a collaborator, Gábor ágoston, calculated that magnetic fields in the sun's core could produce small instabilities in the solar plasma.
3. C
See para.8: Edwards believes the small changes in solar heating produced by Milankovitch cycles are then amplified by feedback mechanisms on Earth.
4. D
See para.11: Nigel Weiss, a solar physicist at the University of Cambridge, is far from convinced. He describes Ehrlich's claims as "utterly implausible".
5. False
See para.5: for the past million years, ice ages have occurred roughly every 100,000 years. Before that, they occurred roughly every 41,000 years.
6. False
See para.7: "In Milankovitch, there is certainly no good idea why the frequency should change from one to another," ... Nor is the transition problem the only one the Milankovitch theory faces.
7. Not Given
See para.8: if sea ice begins to form because of a slight cooling, carbon dioxide?is locked into the ice. That weakens the greenhouse effect. (The passage doesn抰 mention anything about locking Co2 into ice artificially.)
8. True
See para.9: there is no lack of such mechanisms. "If you add their effects together, there is more than enough feedback to make Milankovitch work,"?"The problem now is identifying which mechanisms are at work." This is why scientists like Edwards are not yet ready to give up on the current theory.
9. True
See the sentences in para.9 (According to Edwards, he says. "I can't see any way of testing [Ehrlich's] idea to see where we are in the temperature oscillation.") and para.10 (Ehrlich concedes this. "If there is a way to test this theory on the sun, I can't think of one that is practical).
10. constant
See para.2: According to the standard view, the temperature of the sun's core is held constant by the opposing pressures of gravity and nuclear fusion.
11. orbit
See para.6: Most scientists believe that the ice ages are the result of subtle changes in Earth's orbit, Earth's orbit gradually changes shape from a circle to a slight ellipse and back again roughly every 100,000 years.
12. instabilities
See para.3: magnetic fields in the sun's core could produce small instabilities in the solar plasma. These instabilities would induce localised oscillations in temperature.
13. cycles
See para.4: …allow the sun's core temperature to oscillate around its average temperature of 13.6 million kelvin in cycles lasting either 100,000 or 41,000 years.
14. random
See para.4: Ehrlich says that random interactions within the sun's magnetic field could flip the fluctuations from one cycle length to the other.
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.
Isthere______________totellus?No,nothing.
-----AheavysnowhitmostofthepartsofChinainJanuary,2008.
-----____________terriblenews!
In the earliest stages of man's development he had nomore need of money than animals have.He was content with very simple forms of shelter,made his own rough tools and weapons and could provide food and clothing for himself and his family from natural materials around him.As he became more civilized,however,he began to want better shelter,more efficient tools and weapons,and more comfortable and more lasting clothing than could be provided by his own neighborhood or by the work of his own unskilled hands.For these things he had to turn to the skilled people such as smiths,leather workers or carpenters.It was then that the question of payment arose.
At first he got what he wanted by a simple process ofexchange.The smith who had not the time to look after land or cattle was glad to take meat or grain from the farmer inexchange for an axe or a plough.But as more and more goods which had no fixed exchange value came on the market,exchange became too complicated to be satisfactory.Another problem arose when those who made things wanted to get stocks of wood or leather,or iron,but had nothing to offer in exchange until their finished goods were ready. Thus the difficulties of exchange led by degrees to the invention of money.In some countries easily handled things like seeds or shells were given a certain value and the farmer,instead of paying the smith for a new axe by giving him some meat or grain,gave him so many shells.If the smith had any shells left when he had bought his food,he could get stocks of the raw materials of his trade.In some countries quite large things such as cows or camels or even big flat stones were used for trade.Later,pieces of metal,bearing values according to the rarity of the metal and the size of the pieces,or coins were used.Money as we know it had arrived.
1.Exchange of goods became difficult because _________.
A man became more civilized
B smiths began to look after land or cattle in their spare time
C more and more goods which had no fixed exchange alues came to the marker
D farmers hadn't enough grain or meat to provide for
skilled workers
2.Money was not used until _______.
A paper was invented
B people practiced a simple process of exchange
C nothing could be offered in exchangeD the exchange of one thing for another became too complicated
3.The best title for this passage is _____.
A What is money
B What are money's functions.
C The importance of money
D The beginning of money
Rogue theory of smell gets a boost
1.A controversial theory of how we smell, which claims that our fine sense of odour depends on quantum mechanics, has been given the thumbs up by a team of physicists.
2.Calculations by researchers at University College London (UCL) show that the idea that we smell odour molecules by sensing their molecular vibrations makes sense in terms of the physics involved.
3.That's still some way from proving that the theory, proposed in the mid-1990s by biophysicist Luca Turin, is correct.But it should make other scientists take the idea more seriously.
4."This is a big step forward," says Turin, who has now set up his own perfume company Flexitral in Virginia.He says that since he published his theory, "it has been ignored rather than criticized."
5.Most scientists have assumed that our sense of smell depends on receptors in the nose detecting the shape of incoming molecules, which triggers a signal to the brain.This molecular 'lock and key' process is thought to lie behind a wide range of the body's detection systems: it is how some parts of the immune system recognise invaders, for example, and how the tongue recognizes some tastes.
6.But Turin argued that smell doesn't seem to fit this picture very well.Molecules that look almost identical can smell very different — such as alcohols, which smell like spirits, and thiols, which smell like rotten eggs.And molecules with very different structures can smell similar.Most strikingly, some molecules can smell different — to animals, if not necessarily to humans — simply because they contain different isotopes (atoms that are chemically identical but have a different mass).
7.Turin's explanation for these smelly facts invokes the idea that the smell signal in olfactory receptor proteins is triggered not by an odour molecule's shape, but by its vibrations, which can enourage an electron to jump between two parts of the receptor in a quantum-mechanical process called tunnelling.This electron movement could initiate the smell signal being sent to the brain.
8.This would explain why isotopes can smell different: their vibration frequencies are changed if the atoms are heavier.Turin's mechanism, says Marshall Stoneham of the UCL team, is more like swipe-card identification than a key fitting a lock.
9.Vibration-assisted electron tunnelling can undoubtedly occur — it is used in an experimental technique for measuring molecular vibrations."The question is whether this is possible in the nose," says Stoneham's colleague, Andrew Horsfield.
10.Stoneham says that when he first heard about Turin's idea, while Turin was himself based at UCL, "I didn't believe it".But, he adds, "because it was an interesting idea, I thought I should prove it couldn't work.I did some simple calculations, and only then began to feel Luca could be right." Now Stoneham and his co-workers have done the job more thoroughly, in a paper soon to be published in Physical Review Letters.
11.The UCL team calculated the rates of electron hopping in a nose receptor that has an odorant molecule bound to it.This rate depends on various properties of the biomolecular system that are not known, but the researchers could estimate these parameters based on typical values for molecules of this sort.
12.The key issue is whether the hopping rate with the odorant in place is significantly greater than that without it.The calculations show that it is — which means that odour identification in this way seems theoretically possible.
13.But Horsfield stresses that that's different from a proof of Turin's idea."So far things look plausible, but we need proper experimental verification.We're beginning to think about what experiments could be performed."
14.Meanwhile, Turin is pressing ahead with his hypothesis."At Flexitral we have been designing odorants exclusively on the basis of their computed vibrations," he says."Our success rate at odorant discovery is two orders of magnitude better than the competition." At the very least, he is putting his money where his nose is.
Questions 5-9
Complete the sentences below with words from the passage.Use NO MORE THAN THREE WORDS for each answer.
5.The hypothesis that we smell by sensing the molecular vibration was made by ______.
6.Turin's company is based in ______.
7.Most scientists believed that our nose works in the same way as our ______.
8.Different isotopes can smell different when ______ weigh differently.
9.According to Audrew Horsfield, it is still to be proved that ______ could really occur in human nose.