徐托福tpo1-33阅读原文23翻译

UrbanThecityisanextraordinaryprocessorofmassandenergyandhasitsownmetabolism.Adailyinputofwater,food,andenergyofvariouskindsismatchedbyanoutputofsewage,solidwaste,airpollutants,energy,andmaterialsthathavebeentransformedinsomeway.Thetiesinvolvedareenormous.Manyaspectsofthisenergyuseaffecttheatmosphereofacity,particularlyintheproductionofInwintertheheatproducedbyacitycanequalorsurpasstheamountofheatavailablefromtheSun.Alltheheatthatwarmsabuildingeventuallytransferstothesurroundingair,aprocessthatisquickestwherehousesarepoorlyinsulated.Butanautoproducesenoughheattowarmanaveragehouseinwinter,andifahousewereperfectlyinsulated,oneadultcouldalsoproducemorethanenoughheattowarmit.Therefore,evenwithoutanyindustrialproductionofheat,anurbanareatendstobewarmerthanthecountrysidethatsurroundsit.Theburningoffuel,suchasbycars,isnottheonlysourceofthisincreasedheat.Twootherfactorscontributetothehigheroveralltemperatureincities.Thefirstistheheatcapacityofthematerialsthatconstitutethecity,whichistypicallydominatedbyconcreteandasphalt.Duringtheday,heatfromtheSuncanbeconductedintothesematerialsandstored—tobereleasedatnight.Butinthecountrysidematerialshaveasignificantlylowerheatcapacitybecauseavegetativeblanketpreventsheatfromeasilyflowingintoandoutoftheground.ThesecondfactoristhatradiantheatcomingintothecityfromtheSunistrappedintwoways:(1)byacontinuingseriesofreflectionamongthenumerousverticalsurfacesthatbuildingspresentand(2)bythedustdome,thecloudlikelayerofpollutedairthatmostcitiesproduce.ShortwaveradiationfromtheSunpassesthroughthepollutiondomemoreeasilythanoutgoinglongwaveradiationdoes;thelatterisabsorbedbythegaseouspollutantsofthedomeandreradiatedbacktotheurbansurface.Cities,then,arewarmerthanthesurroundingruralareas,andtogethertheyproduceaphenomenonknownastheurbanheatisland.Heatislandsdevelopbestunderparticularconditionsassociatedwithlightwinds,buttheycanformalmostanytime.Thepreciseconfigurationofaheatislanddependsonseveralfactors.Forexample,thewindcanmakeaheatislandstretchinthedirectionitblows.Whenaheatislandiswelldeveloped,variationscanbeextreme;inwinter,busystreetsincitiescanbe1.7℃warmerthanthesidestreets.Areasneartrafficlightscanbesimilarlywarmerthantheareasbetweenthembecauseoftheeffectofcarsstandingintrafficinsteadofmoving.Theumdifferencesintemperaturebetweenneighboringurbanandruralenvironmentsiscalledtheheat-islandintensityforthatregion.Ingeneral,thelargerthecity,thegreateritsheat-islandintensity.Theactuallevelofintensitydependsonsuchfactorsasthephysicallayout,populationdensity,andproductiveactivitiesofametropolis.Thesurface-atmosphererelationshipsinsidemetropolitanareasproduceanumberofclimaticpeculiarities.Foronething,thepresenceorabsenceofmoistureisaffectedbythespecialqualitiesoftheurbansurface.Withmuchofthebuilt-uplandscapeimpenetrablebywater,evengentlerainrunsoffalmostimmediayfromrooftops,streets,andparkinglots.Thus,citysurfaces,aswellastheairabovethem,tendtobedrierbetweenepisodesofrain;withlittlewateravailableforthecoolingprocessofevaporation,relativehumiditiesareusuallylower.Windmovementsarealsomodifiedincitiesbecausebuildingsincreasethefrictiononairflowingaroundthem.Thisfrictiontendstoslowthespeedofwinds,makingthemfarlessefficientatdispersingpollutants.Ontheotherhand,airturbulenceincreasesbecauseoftheeffectofskyscrapersonairflow.Rainfallisalsoincreasedincities.Thecauseappearstobeinpartgreaterturbulenceintheurbanatmosphereashotairrisesfromthebuilt-upsurface.

城市气的燃烧，比如汽车，并不是这种热量增加的唯一来源。城市较高的平均递（2）通过由大多数城市中受污染空气组成的云状物质来传递。来自的短Seventeenth-CenturyDutchAgricultureandfishingformedtheprimarysectoroftheeconomyintheNetherlandsintheseventeenthcentury.Dutchagriculturewasmodernizedandcommercializednewcropsandagriculturaltechniquesraisedlevelsofproductionsothattheywereinlinewithmarketdemands,andcheapgrainwasimportedannuallyfromtheBalticregioninlargeties.Accordingtoestimates,about120,000tonsofimportedgrainfedabout600,000people:thatisaboutathirdoftheDutchpopulation.Importingthegrain,whichwouldhavebeenexpensiveandtimeconsumingfortheDutchtohaveproducedthemselves,keptthepriceofgrainlowandthusstimulatedindividualdemandforotherfoodstuffsandconsumergoods.Apartfromthis,beingabletogiveuplabor-intensivegrainproductiondboththelandandtheworkformoreproductiveagriculturaldivisions.Thepeasantsspecializedinlivestockhusbandryanddairyfarmingaswellasincultivatingindustrialcropsandfoddercrops:flax,madder,andrapeweregrown,asweretobacco,hops,andturnips.Theseproductswereboughtmostlybyurbanbusinesses.Therewasalsoademandamongurbanconsumersfordairyproductssuchasbutterandcheese,which,inthesixteenthcentury,had emoreexpensivethangrain.Thehighpricesencouragedthepeasantstoimprovetheiranimalhusbandrytechniques;forexample,theybeganfeedingtheiranimalsindoorsinordertoraisethemilkyieldoftheircows.Inadditiontodairyfarmingandcultivatingindustrialcrops,athirdsectoroftheDutcheconomyreflectedthewayinwhichagriculturewasbeingmodernized-horticulture.Inthesixteenthcentury,fruitandvegetablesweretobefoundonlyingardensbelongingtowealthypeople.Thischangedintheearlypartoftheseventeenthcenturywhenhorticulturebecameacceptedasanagriculturalsector.Wholevillagesbegantocultivatefruitandvegetables.Theproducewasthentransportedbywatertomarketsinthecities,wheretheconsumptionoffruitandvegetableswasnolongerrestrictedtothewealthy.Asthedemandforagriculturalproducefrombothconsumersandindustryincreased,agriculturallandbecamemorevaluableandpeopletriedtoworktheavailablelandmoreintensivelyandtoreclaimmorelandfromwetlandsandlakes.Inordertoincreaseproductiononexistingland,thepeasantsmademoreuseofcroprotationand,inparticular,begantoapplyanimalwastetothesoilregularly,ratherthanleavingthefertilizationprocessuptothegrazinglivestock.Forthefirsttimeindustrialwaste,suchasashfromthesoap-boilers,wascollectedinthecitiesandsoldinthecountryasartificialfertilizer.Theincreasedyieldandpriceoflandjustifiedreclaiminganddrainingevenmoreland.TheDutchbattleagainsttheseaislegendary.NoorderkwartierinHolland,withitsnumerouslakesandstretchesofwater,wasparticularlysuitableforlandreclamationandoneofthebiggestprojectsundertakentherewasthedrainingoftheBeemsterlakewhichbeganin1608.TherichestmerchantsinAmsterdamcontributedmoneytoreclaimagood7,100hectaresofland.Forty-threewindmillspoweredthedrainagepumpssothattheywereabletoleasethereclamationtofarmersasearlyas1612,withtheinvestorsreceivingannualleasingpaymentsataninterestrateof17percent.Landreclamation,andbetween1590and1665,almost100,000hectareswerereclaimedfromthewetlandareasofHolland,Zeeland,andFriesland.However,landreclamationdecreasedsignificantlyafterthemiddleoftheseventeenthcenturybecausethepriceofagriculturalproductsbegantofall,makinglandreclamationfarlessprofitableinthesecondpartofthecentury.DutchagriculturewasfinallyaffectedbythegeneralagriculturalcrisisinEuropeduringthelasttwodecadesoftheseventeenthcentury.However,whatisastonishingaboutthisisnotthatDutchagriculturewasaffectedbycriticalphenomenasuchasadecreaseinsalesandproduction,butthefactthatthecrisisappearedonlyrelativelylateinDutchagriculture.InEuropeasawhole,theexceptionalreductioninthepopulationandtherelatedfallindemandforgrainsincethebeginningoftheseventeenthcenturyhadcausedthepriceofagriculturalproductstofall.Dutchpeasantswereabletoremainunaffectedbythiscrisisforalongtimebecausetheyhadspecializedindairyfarmingindustrialcrops,andhorticulture.However,towardtheendoftheseventeenthcentury,theytoowereovertakenbythegeneralagriculturalcrisis.

十七世纪的荷兰农场中，这种商品的消费也不再只是的专利。涨使得开垦和灌溉的土地变得合理化。1608年贝母斯特湖的疏浚。阿姆斯特丹是这些在荷兰农业中发生的相当晚。欧洲总体来讲，异常的人口减少和相应荷兰农民能够在这种中保持长期不受影响是因为他们专注于乳制品和工业。RockArtoftheAustraliaEversinceEuropeanfirstexploredAustralia,peoplehavebeentryingtounderstandtheancientrockdrawingsandcavingscreatedbytheAborigines,theoriginalinhabitantsofthecontinent.Earlyinthenineteenthcentury,encounterswithAboriginalrockarttendedtobeinfrequentandopentospeculativeinterpretation,butsincethelatenineteenthcentury,awarenessoftheextentandvarietyofAustralianrockarthasbeengrowing.InthelatterdecadesofthetwentiethcenturytherewereintensifiedeffortstounderstandandrecordtheabundanceofAustralianrockart.ThesystematicstudyofthisartisarelativelynewdisciplineinAustralia.Overthepastfourdecadesnewdiscoverieshavesteadilyaddedtothebodyofknowledge.Themostsignificantdatahavecomefromaconcentrationonthreemajorquestions.First,whatistheageofAustralianrockart?Second,whatisitsstylisticorganizationandisitpossibletodiscernasequenceorapatternofdevelopmentbetweenstyles?Third,isitpossibletointerpretaccuraythesubject atterofancientrockart,bringtobearallavailablearchaeologicaltechniquesandtheknowledgeofpresent-dayAboriginalTheageofAustralia’srockartisconstantlybeingrevised,andearlierdatingshavebeenproposedastheresultofnewdiscoveries.Currently,reliablescientificevidencedatestheearliestcreationofartonrocksurfacesinAustraliatosomewherebetween30,000and50,000yearsago.Thisinitselfisanalmost prehensiblespanofgenerations,andonethatmakesAustralia’srockarttheoldestcontinuousarttraditionintheworld.AlthoughtheremarkableantiquityofAustralia’srockartisnowestablished,thesequencesandmeaningsofitsimageshavebeenwidelydebated.Sincethemid-1970s,areasonablystablepicturehasformedoftheorganizationofAustralianrockart.Inordertocreateasenseofstructuretothispicture,researchershavereliedonadistinctionthatstillunderliestheformsofmuchindigenousvisualculture—adistinctionbetweengeometricandfigurativeelements.Simplegeometricrepeatedpatterns—circles,concentriccircles,andlines—constitutetheiconography(characteristicimages)oftheearliestrock-artsitesfoundacrossAustralia.Thefrequencywithwhichcertainsimplemotifsappearintheseoldestsiteshasledrock-artresearcherstoadoptadescriptiveterm—thePanaramiteestyle—alabelwhichtakesitsnamefromtheextensiverockpavementsatPanaramiteeNorthindesertSouthAustralia,whicharecoveredwithmotifspeckedintothesurface.Certainfeaturesoftheseengravingsleadtotheconclusionthattheyareofgreatage—geologicalchangeshadclearlyhappenedafterthedesignshadbeenmadeandlocalAboriginalinformants,whenfirstquestionedaboutthem,seemedtoknownothingoftheirorigins.Furthermore,thedesignswerecoveredwith“desertvarnish,”aglazethatdevelopsonrocksurfacesoverthousandsofyearsofexposuretotheelements.ThesimplemotifsfoundatPanaramiteearecommontomanyrock-artsitesacrossAustralia.Indeed,siteswithengravingsofgeometricshapesarealsotobefoundontheislandofTasmania,whichwasseparatedfromtheofthecontinentsome10,000yearsago.Inthe1970swhenthestudyofAustralianarchaeologywasinanexcitingphaseofdevelopment,withthegreatantiquityofrockart ingclear.LesleyMaynard,thearchaeolo