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少儿英语儿童英语故事大全孩子学英语,离不开脍炙人口的寓言小故事,阅读这些英文短文故事,不但能扩充词汇量,还能在阅读之余体味其中深义,瑞思学科英语特别甄选了短文故事大全,为孩子学英语提供有力的英文资料,还有更多英文给本、英语电影、英语动画片、英语书籍、英文儿歌等,敬请__瑞思学科英语,免费获得以上资料哦~01Television电视电视--以快速变化与发展为标志的最普遍、最具有影响力的一项现代技术,正在步入一个极端复杂化与多样化的新时代这个时代承诺重新塑造我们的生活和我们的世界这可以称得上是又一次电子__,其关键在于电视技术与计算机技术的结合电视这个词来源于希腊语词根tele远和拉丁语词根vision景象,可以从字面上理解为来自远处的景象简单说来,电视是以这种方式工作的,通过一个复杂的电子系统,电视能够将一幅图像这幅图像被聚焦在一部摄像机内的一块特殊的光导底片上转换成能经过导线或电缆发送出去的电子脉冲__Television--themostpervasiveandpersuasiveofmoderntechnologies__rkedbyrapidchangeandgrowth–ismovingintoaneweraaneraofextraordinarysophisticationandversatilitywhichpromisestoreshapeourlivesandourworld.Itisanelectronicrevolutionofsorts__depossiblebythe__rriageoftelevisionandcomputertechnologies.ThewordtelevisionderivedfromitsGreektele:distantandLatinvisio:sightrootscanliterallybeinterpretedassightfromadistan__.Verysimplyputitworksinthisway:throughasophisticatedsystemofelectronicstelevisionprovidesthecapabilityofconvertingani__gefocusedonaspecialphotoconductiveplatewithinacameraintoelectronicimpulseswhichcanbesentthroughawireorcable.Theseimpulseswhenfedintoare__ivertelevisionsetcanthenbeelectronicallyreconstitutedintothatsamei__ge.Televisionismorethanjustanelectronicsystemhowever.Itisameansofexpressionaswellasavehicleforcommunicationandassuchbecomesapowerfultoolforreachingotherhu__nbeings.Thefieldoftelevisioncanbedividedintotwocategoriesdeterminedbyitsmeansoftran__ission.Firstthereisbroadcasttelevisionwhichreachesthe__ssesthroughbroad-basedairw__etran__issionoftelevisionsignals.Secondthereisnonbroadcasttelevisionwhichprovidesfortheneedsofindividualsorspecificinterestgroupsthroughcontrolledtran__issiontechniques.Traditionallytelevisionhasbeenamediumofthe__sses.Wearemostfamiliarwithbroadcasttelevisionbecauseithasbeenwithusforaboutthirty-sevenyearsinaformsimilartowhatexiststoday.DuringthoseyearsithasbeencontrolledforthemostpartbythebroadcastnetworksABCNBCandCBSwhoh__ebeenthe__jorpurveyors货物、服务、消息等的提供者供应者ofnewsinfor__tionandentertai__ent.Thesegiantsofbroadcastingh__eactuallyshapednotonlytelevisionbutourper__ptionofitaswell.Weh__ecometolookuponthepicturetubeasasour__ofentertai__entplacingourroleinthisdynamicmediumasthepassiveviewer.当这些电子脉冲__被输入一部接收机电视机时,就可以用电子学的方法把脉冲__重新恢复成同一幅图像但是,电视不仅仅是一个电子系统,它还是一种表达工具和传播渠道因此,电视成了一个对其他人发生影响的强大工具电视这个领域可以根据其发射方式分为两类第一类为广播电视,通过电视__的宽带无线电波发射展现在大众面前;第二类为非广播电视,使用受控的发射技术来满足个人以及某些特殊利益群体的需要电视早已成为大众媒介我们熟悉广播电视,因为广播电视已经以类似目前的方式存在了大约37年在那些年头中,电视绝大部分一直由ABC、NBC、CBS这些广播电视公司控制着,这些广播电视公司一直是新闻、信息和娱乐的主要提供者这些广播业的巨头实际上不仅塑造了电视,而且也塑造了我们对电视的理解我们渐渐把显像管看作是娱乐的来源,让自己成为这个生动的媒介的被动观众02AndrewCarnegieAndrewCarnegieknownastheKingofSteelbuiltthesteelindustryintheUnitedStatesandinthepro__ssbecameoneofthewealthiestmeninAmerica.Hissuc__ssresultedinpartfromhisabilitytoselltheproductandinpartfromhispolicyofexpandingduringperiodsofeconomicdeclinewhenmostofhiscompe_____swerereducingtheirinvestments.Carnegiebelievedthatindividualsshouldprogressthroughhardworkbuthealsofeltstronglythatthewealthyshouldusetheirfortunesforthebenefitofsociety.Heopposedcharitypreferringinsteadtoprovideeducationalopportunitiesthatwouldallowotherstohelpthemselves.Hewho___srich___sdisgra__dheoftensaid.AmonghismorenoteworthycontributionstosocietyarethosethatbearhisnameincludingtheCarnegieInstituteofPittsburghwhichhasalibraryamuseumoffineartsandamuseumofnationalhistory.HealsofoundedaschooloftechnologythatisnowpartofCarnegie-MellonUniversity.OtherphilanthropicgiftsaretheCarnegieEndowmentforInternationalPea__topromoteunderstandingbetweennationstheCarnegieInstituteofWashingtontofundscientificresearchandCarnegieHalltoprovidea__nterforthearts.FewAmericansh__ebeenleftuntouchedbyAndrewCarnegiesgenerosity.Hiscontributionsofmorethanfivemilliondollarsestablished2500librariesin__allcommunitiesthroughoutthecountryandformedthenucleusofthepubliclibrarysystemthatweallenjoytoday.安德鲁·卡内基被称作钢铁大王的安德鲁·卡内基在美国建立了钢铁工业在这个过程中,他变成了美国最富有的人之一他的成功,部分来自于他销售产品的能力,部分来自于经济萧条时期的扩充策略在萧条时期,他的多数对手都在缩减投资卡内基认为个人应该通过努力工作来获得进展,但他也强烈地感到有钱人应该运用他们的财富来为社会谋取福利他__施舍救济,更愿意提供教育机会,使别人自立卡内基经常说富有着死去的人死得可耻他对社会的较重要的贡献都以他的名字命名这些贡献包括匹兹堡卡内基学校这个学校有一个图书馆,一个美术馆和一个国家历史博物馆;他还创立了一所技术学校,这所学校现在是卡内基梅隆大学的一部分;其他的慈善捐赠有为促进国家间了解的卡内基国际和平基金,为科学研究提供经费的华盛顿卡内基学院以及给各种艺术活动提供活动中心的卡内基音乐厅安德鲁·卡内基的慷慨大度几乎影响到每个美___生活由于他超过五百万美元的捐款,2500个图书馆得以建立起来,遍布在美国各地的小村镇,形成了我们今天还在享用的公共图书馆系统的核心03AmericanRevolutionTheAmericanRevolutionwasnotarevolutioninthesenseofaradicalortotalchange.ItwasnotasuddenandviolentoverturningofthepoliticalandsocialframeworksuchaslateroccurredinFranceandRussiawhenbothwerealreadyindependentnations.Significantchangeswereusheredinbuttheywerenotbreathtaking.Whathappenedwasac__leratedevolutionratherthanoutrightrevolution.Duringtheconflictitselfpeoplewentonworkingandpraying__rryingandplaying.Mostofthemwerenotseriouslydisturbedbytheactualfightingand__nyofthemoreisolatedcommunitiesscar__lyknewthatawarwason.AmericasWarofIndependen__heraldedthebirthofthreemodernnations.OnewasCanadawhichre__iveditsfirstlargeinfluxofEnglish-speakingpopulationfromthethousandsofloyalistswhofledtherefromtheUnitedStates.AnotherwasAustraliawhichbecameapenalcolonynowthatAmericawasnolonger__ailableforprisonersanddebtors.Thethirdnewcomer--theUnitedStates--baseditselfsquarelyonrepublicanprinciples.Yeteventhepoliticaloverturnwasnotsorevolutionaryasonemightsuppose.InsomestatesnotablyConnecticutandRhodeIslandthewarlargelyratifiedacolonialself-rulealreadyexisting.Britishofficialseverywhereoustedwererepla__dbyahome-growngoverningclasswhichpromptlysoughtalocalsubstituteforkingandParliament.美国__美国__其实并不算是一场__,因为它并未导致完全的和彻底的变化这次__并不是对__和社会框架的一次突然和猛烈的__,象后来在已经是__国家的法国和__所爆发的__那样__带来了重大的变化,但并非翻天覆地,所发生的只是进化的加速,而不是一场彻底的__;在冲突期间,人们仍然上班、做礼拜、结婚、玩耍多数人并没有受到实际战斗的严重影响许多较闭塞的社区对这场战争几乎一无所知美国__战争宣布了三个现代国家的诞生,其中一个是______的第一大批讲英语的流入人口来自于成千上万英王的效忠者,这些人从美国逃到了___另一个国家是澳大利亚,因为美国不再是容纳罪犯和欠债者的国度了,澳大利亚就变成了一个惩治罪犯的殖民地注__战争前,英国__将罪犯流放到美国第三个国家就是美国,它完全建立在共和原则基础上即使__上的__也不如人们可能想象的那样具有__性在一些州,特别是康涅狄格和罗德岛,战争基本上只是承认了已经存在的殖民地的自治四处被驱逐的英国官员都被本土的统治阶级所替代,这个统治阶级迅速地以地方权力机关来替代国王和议会04SuburbanizationIfbysuburbismeantanurban__rginthatgrowsmorerapidlythanitsalreadydevelopedinteriorthepro__ssofsuburbanizationbeganduringtheemergen__oftheindustrialcityinthesecondquarterofthenineteenth__ntury.Beforethatperiodthecitywasa__allhighlycompactclusterinwhichpeoplemovedaboutonfootandgoodswereconveyedbyhorseandcart.Buttheearlyfactoriesbuiltinthe1830sand1840swerelocatedalongwaterwaysandnearrailheadsattheedgesofcitiesandhousingwasneededforthethousandsofpeopledrawnbytheprospectofemployment.Intimethefactoriesweresurroundedbyproliferatingmilltownsofapartmentsandrowhousesthatabuttedtheolder__incities.Asadefenseagainstthisencroachmentandtoenlargetheirtaxbasesthecitiesappropriatedtheirindustrialnei___ors.In1854forexamplethecityofPhiladelphiaannexedmostofPhiladelphiaCounty.Similarmunicipal__neuverstookpla__inChicagoandinNewYork.IndeedmostgreatcitiesoftheUnitedStatesachievedsuchstatusonlybyincorporatingthecommunitiesalongtheirborders.Withtheac__lerationofindustrialgrowthcameacuteurbancrowdingandaccompanyingsocialstress--conditionsthatbegantoapproachdisastrousproportionswhenin1888thefirstcommerciallysuc__ssfulelectrictractionlinewasdeveloped.Withinafewyearsthehorse-drawntrolleyswereretiredandelectricstreetcarnetworkscrisscrossedandconnectedevery__jorurbanareafosteringaw__eofsuburbanizationthattransformedthecompactindustrialcityintoadispersedmetropolis.Thisfirstphaseof__ss-scalesuburbanizationwasreinfor__dbythesimultaneousemergen__oftheurbanMiddleClasswhosedesiresforhomeownershipinnei___orhoodsfarfromtheaginginnercityweresatisfiedbythedevelopersofsingle-familyhousingtracts.郊区的发展如果郊区指的是比已建好的城市内部发展更为迅速的城市边缘地带,那么郊区化可以说始于1825年至1850年工业化城市出现期间在这之前,城市只是高度密集的小聚居群在其中,人们步行走动,商品靠马车来运送但是建于18世纪三四十年代的早期工厂位于城边的航道和铁路附近,被工作机会吸引到这里的成千上万的人们需要住房渐渐地,在与旧有的主要城区相毗邻的地方,不断涌现出由排房和__楼组成的工人聚居区,包围了工厂作为对这种侵蚀的自卫,也为了扩大它们收税的地域范围,城市吞并了工业化的临近地带,比如1854年费城的城区就兼并了费县的绝大部分地区相似的城市化也发生在芝加哥和纽约今天很多美国的大城市其实就是靠吞并它们附近的边缘地区而变成大都会的随着工业化的加速发展,城市里出现了严重拥挤和相伴而来的社会压力当1888年第一条商业上成功的电气化铁轨被制造出来时,压力开始接近危机的程度几年之内,马车就被废弃了,电车网相互交织连接着各个重要的城区,从而形成了一种郊区化的潮流,即密集的工业城市转变成了分散的都市此时城市中产阶级的出现进一步加强了第一波大规模郊区化这些中产阶级希望在远离老旧城市的地区拥有__,单一家庭__地区的__者满足了他们的愿望5TypesofSpeechStandardusageincludesthosewordsandexpressionsunderstoodusedandac__ptedbya__jorityofthespeakersofalanguageinanysituationregardlessoftheleveloffor__lity.Assuchthesewordsandexpressionsarewelldefinedandlistedinstandarddictionaries.Colloquiali__sontheotherhandarefamiliarwordsandidiomsthatareunderstoodbyalmostallspeakersofalanguageandusedininfor__lspeechorwritingbutnotconsideredappropriateformorefor__lsituations.Almostallidio__ticexpressionsarecolloquiallanguage.Slanghoweverreferstowordsandexpressionsunderstoodbyalargenumberofspeakersbutnotac__ptedasgoodfor__lusagebythe__jority.Colloquialexpressionsandevenslang__ybefoundinstandarddictionariesbutwillbesoidentified.Bothcolloquialusageandslangaremorecommoninspeechthaninwriting.Colloquialspeechoftenpassesintostandardspeech.Someslangalsopassesintostandardspeechbutotherslangexpressionsenjoymomentarypopularityfollowedbyobscurity.Insomecasesthe__jorityneverac__pts__rtainslangphrasesbutneverthelessretainsthemintheircollectivememories.Everygenerationseemstorequireitsownsetofwordstodescribefamiliaro__ectsandevents.Ithasbeenpointedoutbyanumberoflinguiststhatthreeculturalconditionsarene__ssaryforthecreationofalargebodyofslangexpressions.Firsttheintroductionandac__ptan__ofnewo__ectsandsituationsinthesociety;secondadiversepopulationwithalargenumberofsubgroups;thirdassociationamongthesubgroupsandthe__joritypopulationFinallyitisworthnotingthatthetermsstandardcolloquialandslangexistonlyasabstractlabelsforscholarswhostudylanguage.Onlyatinynumberofthespeakersofanylanguagewillbeawarethattheyareusingcolloquialorslangexpressions.MostspeakersofEnglishwillduringappropriatesituationsselectanduseallthreetypesofexpressions.语言的类型标准用法包括那些为使用这种语言的大多数人在任何场合下理解、使用和接受的词和短语,而不论该场合是否正式这些词和短语的意义已很确定并被列入了标准词典中相反,俗语是指那些几乎所有讲这种语言的人都理解并在非正式的口头或书面中使用,却不适用于更正规的一些场合的词和短语几乎所有的习惯用语都属于俗语,而俚语指的是为很多讲这种语言的人理解但大多数人不把它们列入好的、正式用法之内的词和短语;俗语甚至俚语都可能在标准字典中查到,但是字典中会标明它们的性质俗语和俚语词汇的应用都是口头较多、笔头较少俗语用法经常地被接受为标准用法一些俚语也变成了标准用法,但另外一些俚语只经历了短暂的流行,而后就被弃之不用了有时候,多数人从来不接受某些俚语,但是他们把这些俚语保存到集中记忆中每一代人似乎都需要独有的一套词汇来描述熟知的物体和__很多语言学家指出,大量俚语的形成需要三个文化条件第一,对社会中新事物的引入和接受;第二,一个由大量子群构成的多样化人口;第三,各子群与多数人口之间的__最后需要提到的是,标准语、俗语和俚语这些术语只是对研究语言的专家才有用的抽象标签不论何种语言,只会有很小一部分使用者能够意识到他们是在使用俗语或俚语讲英语的多数人能够在适当的场合中选择使用所有这三种语言类型06TheLanguageofMusicApainterhangshisorherfinishedpictureonawallandeveryonecanseeit.Acomposerwritesaworkbutnoonecanhearituntilitisperformed.Professionalsingersandplayersh__egreatresponsibilitiesforthecomposerisutterlydependentonthem.Astudentofmusicneedsaslongandasarduousatrainingtobecomeaperformerasamedicalstudentneedstobecomeadoctor.Mosttrainingiscon__rnedwithtechniqueformusiciansh__etoh__ethemuscularproficiencyofanathleteoraballetdan__r.Singerspracti__breathingeverydayastheirvocalchordswouldbeinadequatewithoutcontrolledmuscularsupport.Stringplayerspracti__movingthefingersofthelefthandupanddownwhiledrawingthebowtoandfrowiththerightarm--twoentirelydifferentmovements.Singersandinstrumentalistsh__etobeabletogeteverynoteperfectlyintune.Pianistsaresparedthisparticularanxietyforthenotesarealreadytherewaitingforthemanditisthepianotunersresponsibilitytotunetheinstrumentforthem.Buttheyh__etheirowndifficulties:thehammersthathitthestringsh__etobecoaxednottosoundlikepercussionandeachoverlappingtonehastosoundclear.Thisproblemofgettingcleartextureisonethatconfrontsstudentconductors:theyh__etolearntoknoweverynoteofthemusicandhowitshouldsoundandtheyh__etoaimatcontrollingthesesoundswithfanaticalbutselflessauthority.Techniqueisofnouseunlessitiscombinedwithmusicalknowledgeandunderstanding.Greatartistsarethosewhoaresothoroughlyathomeinthelanguageofmusicthattheycanenjoyperformingworkswritteninany__ntury.音乐的语言画家将已完成的作品挂在墙上,每个人都可以观赏到作曲家写完了一部作品,得由演奏者将其演奏出来,其他人才能得以欣赏因为作曲家是如此完全地依赖于职业歌手和职业演奏者,所以职业歌手和职业演奏者肩上的担子可谓不轻一名学音乐的学生要想成为一名演奏者,需要经受__的、严格的训练,就象一名医科的学生要成为一名医生一样绝大多数的训练是技巧性的音乐家们控制肌肉的熟练程度,必须达到与运动员或巴蕾舞演员相当的水平歌手们每天都练__嗓子,因为如果不能有效地控制肌肉的话,他们的声带将不能满足演唱的要求弦乐器的演奏者练习的则是在左手的手指上下滑动的同时,用右手前后拉动琴弓--两个截然不同的动作歌手和乐器演奏者必须使所有的音符完全相同协调钢琴家们则不用操这份心,因为每个音符都已在那里等待着他们了给钢琴调音是调音师的职责但调音师们也有他们的难处他们必须耐心地调理敲击琴弦的音锤,不能让音锤发出的声音象是打击乐器,而且每个交叠的音都必须要清晰如何得到乐章清晰的纹理是学生指挥们所面临的难题他们必须学会了解音乐中的每一个音及其发音之道他们还必须致力于以热忱而又客观的权威去控制这些音符除非是和音乐方面的知识和悟性结合起来,单纯的技巧没有任何用处艺术家之所以伟大在于他们对音乐语言驾轻就熟,以致于可以满怀喜悦地演出写于任何时代的作品07SchoolingandEducationItiscommonlybelievedintheUnitedStatesthatschooliswherepeoplegotogetaneducation.Neverthelessithasbeensaidthattodaychildreninterrupttheireducationtogotoschool.Thedistinctionbetweenschoolingandeducationimpliedbythisre__rkisimportant.Educationismuchmoreopen-endedandall-inclusivethanschooling.Educationknowsnobounds.Itcantakepla__anywherewhetherintheshowerorinthejobwhetherinakitchenoronatractor.Itincludesboththefor__llearningthattakespla__inschoolsandthewholeuniverseofinfor__llearning.Theagentsofeducationcanrangefromareveredgrandparenttothepeopledebatingpoliticsontheradiofromachildtoadistinguishedscientist.Whereasschoolinghasa__rtainpredictabilityeducationquiteoftenprodu__ssurprises.Achan__conversationwithastranger__yleadapersontodiscoverhowlittleisknownofotherreligions.Peopleareengagedineducationfrominfancyon.Educationthenisaverybroadinclusiveterm.Itisalifelongpro__ssapro__ssthatstartslongbeforethestartofschoolandonethatshouldbeanintegralpartofonesentirelife.Schoolingontheotherhandisaspecificfor__lizedpro__sswhosegeneralpatternvarieslittlefromonesettingtothenext.Throughoutacountrychildrenarriveatschoolatapproxi__telythesametimetakeassignedseatsaretaughtbyan_____usesimilartextbooksdohomeworktakeexamsandsoon.Thesli__sofrealitythataretobelearnedwhethertheyarethealphabetoranunderstandingoftheworkingsofgover__enth__eusuallybeenlimitedbytheboundariesofthesu__ectbeingtaught.Forexamplehighschoolstudentsknowthattheyarenotlikelytofindoutintheirclassesthetruthaboutpoliticalproblemsintheircommunitiesorwhatthenewestfilm__kersareexperimentingwith.Therearedefiniteconditionssurroundingthefor__lizedpro__ssofschooling.上学与受教育在美国,人们通常认为上学是为了受教育而现在却有人认为孩子们上学打断了他们受教育的过程这种观念中的上学与受教育之间的区别非常重要与上学相比,教育更具开放性,内容更广泛教育不受任何限制它可以在任何场合下进行,在淋浴时,在工作时,在厨房里或拖拉机上它既包括在学校所受的正规教育,也包括一切非正规教育传授知识的人可以是德高望重的老者,可以是收音机里进行__辩论的人们,可以是小孩子,也可以是知名的科学家上学读书多少有点可预见性,而教育往往能带来意外的发现与陌生人的一次随意谈话可能会使人认识到自己对其它宗教其实所知甚少人们从幼时起就开始受教育因此,教育是一个内涵很丰富的词,它自始至终伴随人的一生,早在人们上学之前就开始了教育应成为人生命中不可缺少的一部分然而,上学却是一个特定的形式化了的过程在不同场合下,它的基本形式大同小异在全国各地,孩子们几乎在同一时刻到达学校,坐在指定的座位上,由一位成年人传授知识,使用大致相同的教材,做作业,考试等等他们所学的现实生活中的一些片断,如字母表或__的运作,往往受到科目范围的限制例如,高中生们知道,在课堂上他们没法弄清楚他们社区里____的真情,也不会了解到最新潮的电影制片人在做哪些尝试学校教育这一形式化的过程是有特定的限制的08TheDefinitionofPri__Pri__sdeterminehowresour__saretobeused.Theyarealsothemeansbywhichproductsandservi__sthatareinlimitedsupplyarerationedamongbuyers.Thepri__systemoftheUnitedStatesisacomplexnetworkcomposedofthepri__sofalltheproductsboughtandsoldintheeconomyaswellasthoseofamyriadofservi__sincludinglaborprofessionaltransportationandpublic-utilityservi__s.Theinterrelationshipsofallthesepri__s__keupthesystemofpri__s.Thepri__ofanyparticularproductorservi__islinkedtoabroadcomplicatedsystemofpri__sinwhicheverythingseemstodependmoreorlessuponeverythingelse.Ifoneweretoaskagroupofrandomlyselectedindividualstodefinepri____nywouldreplythatpri__isanamountofmoneypaidbythebuyertothesellerofaproductorservi__orinotherwordsthatpri__isthemoneyvalueofaproductorservi__asagreeduponina__rkettransaction.Thisdefinitionisofcoursevalidasfarasitgoes.Foracompleteunderstandingofapri__inanyparticulartransactionmuchmorethantheamountofmoneyinvolvedmustbeknown.Boththebuyerandthesellershouldbefamiliarwithnotonlythemoneyamountbutwiththeamountandqualityoftheproductorservi__tobeexchangedthetimeandpla__atwhichtheexchangewilltakepla__andpaymentwillbe__detheformofmoneytobeusedthecredittermsanddiscountsthatapplytothetransactionguaranteesontheproductorservi__deliverytermsreturnprivilegesandotherfactors.Inotherwordsbothbuyerandsellershouldbefullyawareofallthefactorsthatcomprisethetotalpackagebeingexchangedfortheasked-foramountofmoneyinorderthatthey__yevaluateagivenpri__.__的定义__决定资源的使用方式__也是有限的产品与服务在买方中的配给手段美国的__系统是复杂的网状系统,包括经济生活中一切产品买卖的__,也包括名目繁多的各种服务,诸如劳动力、专职人员、交通运输、公共事业等服务的__所有这些__的内在__构成了__系统任何一种个别产品或服务的__都与这个庞大而复杂的系统密切相关,而且或多或少地受到系统中其它成份的制约如果随机挑选一群人,问问他们如何定义__,许多人会回答__就是根据卖方提供的产品或服务,买方向其付出的钱数换句话说,__就是市场交易中大家认同的产品或服务的货币量该定义就其本身来说自有其道理但要获得对__在任何一桩交易中的完整认识,就必须考虑到大量非货币因素的影响买卖双方不但要清楚交易中的钱数,而且要非常熟悉交易物的质量和数量,交易的时间、地点,采用哪种形式付款,有怎样的缓付和__,对交易物的质量保证、交货条款、退赔权利等等也就是说,为了能估算索价,买卖双方必须通晓构成交易物价格的通盘细节09ElectricityThemodernageisanageofelectricity.Peoplearesousedtoelectriclightsradiotelevisionsandtelephonesthatitishardtoi__ginewhatlifewouldbelikewithoutthem.Whenthereisapowerfailurepeoplegropeaboutinflickeringcandlelightcarshesitateinthestreetsbecausetherearenotrafficlightstoguidethemandfoodspoilsinsilentrefrigerators.Yetpeoplebegantounderstandhowelectricityworksonlyalittlemorethantwo__nturiesago.Naturehasapparentlybeenexperimentinginthisfieldformillionsofyears.Scientistsarediscoveringmoreandmorethatthelivingworld__yhold__nyinterestingsecretsofelectricitythatcouldbenefithu__nity.Allliving__llssendouttinypulsesofelectricity.Astheheartbeatsitsendsoutpulsesofrecord;theyformanelectrocardiogramwhichadoctorcanstudytodeterminehowwelltheheartisworking.Thebraintoosendsoutbrainw__esofelectricitywhichcanberecordedinanelectroen__phalogram.Theelectriccurrentsgeneratedbymostliving__llsareextremely__all--oftenso__allthatsensitiveinstrumentsareneededtorecordthem.Butinsomeani__ls__rtainmuscle__llsh__ebecomesospecializedaselectricalgeneratorsthattheydonotworkasmuscle__llsatall.Whenlargenumbersofthese__llsarelinkedtogethertheeffectscanbeastonishing.Theelectriceelisana__zingstoragebattery.Itcansendajoltofasmuchaseighthundredvoltsofelectricitythroughthewaterinwhichitlives.Anelectrichousecurrentisonlyonehundredtwentyvolts.As__nyasfour-fifthsofallthe__llsintheelectriceelsbodyarespecializedforgeneratingelectricityandthestrengthoftheshockitcandelivercorrespondsroughlytothelengthofitsbody.电当今时代是电气时代人们对电灯、收音机、电视和__早已司空见惯以致很难想象没有它们生活会变成什么样当停电时,人们在摇曳不定的烛光下暗中摸索;因没有红绿灯的指示,汽车在道路上迟疑不前;冰箱也停止工作,导致食物变质人们只是在两个世纪前一点才开始了解电的使用原理,自然界却显然在这方面经历过了数百万年科学家不断发现许多生物世界里可能有益于人类的关于电的有趣秘密所有生物细胞都会发出微小的电脉冲当心脏跳动时,把它发出的脉冲记录下来就成了心电图,这可让医生了解心脏的工作状况大脑也发出脑电波,这可在脑电图上记录下来许多生物细胞发出的电流都是极微小的,小到要用灵敏仪器才能记录和测量但一些动物的某些肌肉细胞能转化成一个个发电机,以致完全失去肌肉细胞的功能这种细胞大量地连接在一起时产生的效果将是非常令人吃惊的电鳗就是一种令人惊异的蓄电池它可以在水中发出相当于800伏特电压电流家庭用户的电压只有120伏特在电鳗的身体里,多至五分之四的细胞都专门用来发电,而且发出的电流的强度大约和它身体的长度成正比10TheBeginningofDra__Thereare__nytheoriesaboutthebeginningofdra__inancientGreece.Theonemostwidelyac__ptedtodayisbasedontheassumptionthatdra__evolvedfromritual.Theargumentforthisviewgoesasfollows.Inthebeginninghu__nbeingsviewedthenaturalfor__softheworld-eventheseasonalchanges-asunpredictableandtheysoughtthroughvariousmeanstocontroltheseunknownandfearedpowers.Thosemeasureswhichappearedtobringthedesiredresultswerethenretainedandrepeateduntiltheyhardenedintofixedrituals.Eventuallystoriesarosewhichexplainedorveiledthemysteriesoftherites.Astimepassedsomeritualswereabandonedbutthestorieslatercalledmythspersistedandprovided__terialforartanddra__.Thosewhobelievethatdra__evolvedoutofritualalsoarguethatthoseritescontainedtheseedoftheaterbecausemusicdan____sksandcostumeswerealmostalwaysused.Furthermoreasuitablesitehadtobeprovidedforperfor__n__sandwhentheentirecommunitydidnotparticipateacleardivisionwasusually__debetweentheactingareaandtheauditorium.Inadditiontherewereperformersandsin__considerableimportan__wasattachedto__oidingmistakesintheenactmentofritesreligiousleadersusuallyassumedthattask.Wearing__sksandcostumestheyoftenimpersonatedotherpeopleani__lsorsupernaturalbeingsandmimedthedesiredeffect--suc__ssinhuntorbattlethecomingraintherevivaloftheSun--asanactormight.Eventuallysuchdra__ticrepresentationswereseparatedfromreligiousactivities.Anothertheorytra__sthetheatersoriginfromthehu__ninterestinstory____ing.Accordingtothisviewtalesaboutthehuntwarorotherfeatsaregraduallyelaboratedatfirstthroughtheuseofimpersonationactionanddialoguebyanarratorandthenthroughtheassumptionofeachoftherolesbyadifferentperson.Acloselyrelatedtheorytra__stheatertothosedan__sthatarepri__rilyrhythmicalandgymnasticorthatareimitationsofani__lmovementsandsounds.戏剧___关于古希腊戏剧___存在着多种理论,其中一个最普遍为人接受的理论假设认为戏剧从仪式演化而来这个观点是这样进行论证的一开始,人类把世界上的自然力量,甚至季节的变化都看成是不可预料的他们试图通过各种方式去控制这些未知的、令人恐惧的力量那些似乎带来了满意结果的手段就被保留下来并且重复直到这些手段固化为不变的仪式,最后产生了能够解释或者掩盖这些仪式神秘性的故事随着时间的推移,一些仪式被废弃了,但这些后来被称作神话的故事流传下来并且为艺术和戏剧提供了素材认为戏剧从仪式演化而来的人们还认为那些仪式包含了戏剧的基本因素,因为音乐、舞蹈、面具和服装几乎经常被使用,而且,必须为演出提供一个合适的地点;如果不是整个社区共同参加演出,经常在演出区和观众席之间划分出明显的分界另外,仪式中还有演员,而且宗教领袖通常承担演出任务,因为在仪式的执行中避免错误的发生被认为有相当大的重要性;他们经常带着面具,穿着服装象演员那样扮演其它人、动物或超自然的生灵,用动作来表演以达到所需要的效果,比如打猎的成功或战斗的胜利、将至的雨、太阳的复活最后这些戏剧性的表演从宗教活动中分离了出来另一个追溯戏剧起源的理论认为它来自人们对叙述故事的兴趣根据这个观点,故事关于狩猎、战争或者其它伟绩是逐渐丰富起来的首先通过一个讲解人来运用模仿、表演和对话,然后再由不同的人扮演各自的角色;另一个与之紧密相关的理论将戏剧___追溯至舞蹈,这些舞蹈大体上是有节奏感的和体操式的那一类,或者是对动物动作和声音的模仿11ArchaeologyArchaeologyisasour__ofhistorynotjustahumbleauxiliarydiscipline.Archaeologicaldataarehistoricaldocumentsintheirownrightnotmereillustrationstowrittentexts.Justasmuchasanyotherhistoriananarchaeologiststu___sandtriestoreconstitutethepro__ssthathascreatedthehu__nworldinwhichwelive--andusourselvesinsofarasweareeachcreaturesofourageandsocialenviro__ent.Archaeologicaldataareallchangesinthe__terialworldresultingfromhu__nactionormoresuccinctlythefossilizedresultsofhu__nbeh__ior.Thesumtotaloftheseconstituteswhat__ybecalledthearchaeologicalrecord.Thisrecordexhibits__rtainpeculiaritiesanddeficienciestheconsequen__sofwhichprodu__arathersuperficialcontrastbetweenarchaeologicalhistoryandthemorefamiliarkindbaseduponwrittenrecords.Notallhu__nbeh__iorfossilizes.ThewordsIutterandyouhearasvibrationsintheairare__rtainlyhu__nchangesinthe__terialworldand__ybeofgreathistoricalsignifican__.Yettheyle__enosortoftra__inthearchaeologicalrecordsunlesstheyarecapturedbyadictaphoneorwrittendownbyaclerk.Themovementoftroopsonthebattlefield__ychangethecourseofhistorybutthisisequallyephemeralfromthearchaeologistsstandpoint.Whatisperhapsworsemostorganic__terialsareperishable.Everything__deofwoodhidewoollinengrasshairandsimilar__terialswilldecayandvanishindustinafewyearsor__nturiess__eunderveryex__ptionalconditions.Inarelativelybriefperiodthearchaeologicalrecordisredu__dtomerescrapsofstoneboneglassmetalandearthenware.Stillmodernarchaeologybyapplyingappropriatetechniquesandcomparativemethodsaidedbyafewluckyfindsfrompeat-bogsdesertsandfrozensoilsisabletofillupagooddealofthegap.考古学考古学是历史学的一个来源,而不是地位卑微的辅助学科考古学资料本身也是一种历史文献,而不仅仅是文字资料的例证正象任何一位历史学家那样,考古学家研究调查并尽力去重构一个过程这个过程创造了我们生活的人类世界,也创造了我们自身,因为我们都是我们所处的时代和社会环境的产物考古学的资料就是人类行为所造成的物质变化更简洁地说,是石化了的人类行为这些变化的总和构成了我们所说的考古学记录这些记录自有其独特和不足之处,因而导致人们对考古历史和更熟悉的文字记载历史进行相当肤浅的对比并不是所有的人类行为都留下化石我说的话,你通过空气振动听见,这当然是人类造成的物质变化,也可能有重大的历史意义,但这些话在考古学中未留下丝毫痕迹,除非有人用录音机录下来或文书把这些话写了下来战场上军队的行动可能改变历史的进程,但从考古学的观点来看,这同样是难以捕捉的;可能更糟的是,多数有机物质会腐烂任何由木头、生皮、绒线、亚麻、草、毛发以及相似物质做成的东西除非在一些非常特殊的条件下,几年或几个世纪以后,会在尘土中腐烂并消失在短时期内,能留下考古记录的东西也都会退化为石头、骨头、玻璃、金属和陶器的碎片然而,现__古学通过运用适当的技术和比较的方法,在从泥炭、沙漠和冻土中所获得的一些幸运发现的辅助下,能够填充这个空缺的很大部分12MuseumsFromBostontoLosAngelesfromNewYorkCitytoChicagotoDallasmuseumsareeitherplanningbuildingorwrappingupwholesaleexpansionprograms.Theseprogramsalreadyh__eradicallyalteredfacadesandfloorplansorareexpectedtodosointhenot-too-distantfuture.InNewYorkCityalonesix__jorinstitutionsh__espreadupandoutintotheairspa__andnei___orhoodsaroundthemorarepreparingtodoso.Thereasonsforthisconfluen__ofactivityarecomplexbutonefactorisaconsiderationeverywhere--spa__.Withcollectionsexpandingwiththeneedsandfunctionsofmuseumschangingemptyspa__hasbecomeaverypreciouscommodity.ProbablynowhereinthecountryisthismoretruethanatthePhiladelphiaMuseumofArtwhichhasneededadditionalspa__fordecadesandwhichre__iveditslastsignificantfa__lifttenyearsago.Becauseofthespa__crunchtheArtMuseumhasbecomeincreasinglycautiousinconsideringacquisitionsanddonationsofartinsomecasespassingupopportunitiestostrengthenitscollections.Deac__ssing--orsellingoff--worksofarthastakenonnewimportan__becauseofthemuseumsspa__problems.Andincreasinglycuratorsh__ebeenfor__dtojugglegalleryspa__rotatingone__sterpie__intopublicviewwhileanotherissenttostorage.Despitetheclearneedforadditionalgalleryandstoragespa__howeverthemuseumhasnoplannoplantobreakoutofitsenvelopeinthenextfifteenyearsaccordingtoPhiladelphiaMuseumofArtspresident.博物馆从波士顿到洛杉机,从纽约到芝加哥、到达拉斯,所有的博物馆或者正在筹划、建造或者正在完成大规模的扩建计划这些计划或者已经根本性地改变了博物馆门面与展厅的设计,或者预期在不久的将来会这样做单单在纽约市,六个主要机构或者已经向空中和周围扩展,或者正准备这样做大家一致行动的原因是复杂多样的,但其中的一个因素是普遍考虑的空间问题随着收藏品的增多,也随着博物馆的需要和功能的变化,空间已经变成了一项非常珍贵的商品在我国,也许没有任何其他地方比费城艺术博物馆更符合这个事实这个博物馆几十年来一直需要额外的空间,十年前进行了最后一次重大的翻新由于空间紧缺,该艺术博物馆在考虑__与受赠艺术品已越来越谨慎,有时甚至放弃增强艺术收藏的机会由于博物馆的空间问题,将艺术品脱手或者说卖掉已经有了新的重要意义博物馆馆长们被迫巧妙轮换利用陈列馆的空间,轮流着把一些艺术杰作向公众展出,而把另一些送入存储室中虽然对额外的陈列室和存储室空间需要很明显,但据费城艺术博物馆经理讲博物馆还没有在未来十五年打破这个束缚的计划13SkyscrapersandEnviro__entInthelate1960s__nypeopleinNorthAmericaturnedtheirattentiontoenviro__entalproblemsandnewsteel-and-glassskyscraperswerewidelycriticized.Ecologistspointedoutthataclusteroftallbuildingsinacityoftenoverburdenspublictransportationandparkinglotcapacities.Skyscrapersarealsol__ishconsumersandwastersofelectricpower.Inonere__ntyeartheadditionof17millionsquarefeetofskyscraperoffi__spa__inNewYorkCityraisedthepeakdailyde__ndforelectricityby120000kilowatts--enoughtosupplytheentirecityofAlbanyNewYorkforaday.Glass-walledskyscraperscanbeespeciallywasteful.Theheatlossorgainthroughawallofhalf-inchplateglassismorethantentimesthatthroughatypical__sonrywallfilledwithinsulationboard.Tolessenthestrainonheatingandair-conditioningequipmentbuildersofskyscrapersh__ebeguntousedouble-glazedpanelsofglassandreflectiveglassescoatedwithsilverorgoldmirrorfilmsthatredu__glareaswellasheatgain.Howevermirror-walledskyscrapersraisethetemperatureofthesurroundingairandaffectnei___oringbuildings.Skyscrapersputaseverestrainonacityssanitationfacilitiestoo.IffullyoccupiedthetwoWorldTrade__ntertowersinNewYorkCitywouldalonegenerate
2.25milliongallonsofrawsewageeachyear--asmuchasacitythesizeofStanfordConnecticutwhichhasapopulationofmorethan
109000.摩天大楼与环境60年代后期,许多北美人把注意力转向了环境问题,那些崭新的玻璃钢摩天大楼受到了广泛的批评生态学家指出,城市中密集的高层建筑经常给公共交通与停车场的承载能力造成过重的负担摩天大楼还是电能的过度消费者与浪费者最近的某一年,纽约市摩天___1,700万英尺办公__的增加使电能的最高日需求量提高了120,000千瓦这些电能足以供纽约的整个奥尔巴尼市使用一天玻璃表面的摩天大楼特别地浪费通过半英寸的平板玻璃墙壁损失或增加的热量是典型的加入绝缘板的石墙所允许的热量损失或增加的十倍以上为了减轻取暖设备或空调设备的压力,摩天大楼的建造者们已经开始使用双面上釉的玻璃镶板和涂上了金色或银色反光薄膜的反光玻璃,来减少强光照射和热量的增加;但是,镜面的摩天大楼会提高周围空气的温度并会对附近的建筑物产生影响摩天大楼也对城市的卫生设施造成了沉重的压力单单纽约市的二个世界贸易中心大楼如果完全被占满的话,每年就会产生2,250,000加仑的污水这相当于康涅狄格州的斯坦福市这样大的城市一年所产生的污水量,而康州的斯坦福市拥有109,000人口14ARareFossilRecordThepreservationofembryosandjuvenilesisarateoccurren__inthefossilrecord.Thetinydelicateskeletonsareusuallyscatteredbysc__engersordestroyedbyweatheringbeforetheycanbefossilized.Ichthyosaurshadahigherchan__ofbeingpreservedthandidterrestrialcreaturesbecauseas__rineani__lstheytendedtoliveinenviro__entslesssu__ecttoerosion.Stilltheirfossilizationrequiredasuiteoffactors:aslowrateofdecayofsofttissueslittlesc__engingbyotherani__lsalackofswiftcurrentsandw__estojumbleandcarryaway__allbonesandfairlyrapidburial.Giventhesefactorssomeareash__ebecomeatreasuryofwell-preservedichthyosaurfossils.ThedepositsatHolzmadenGermanypresentaninterestingcasefor____ysis.Theichthyosaurre__insarefoundinblackbituminous__rineshalesdepositedabout190millionyearsago.Overtheyearsthousandsofspecimensof__rinereptilesfishandinvertebratesh__ebeenrecoveredfromtheserocks.Thequalityofpreservationisoutstandingbutwhatisevenmoreimpressiveisthenumberofichthyosaurfossilscontainingpreservedembryos.Ichthyosaurswithembryosh__ebeenreportedfrom6differentlevelsoftheshaleina__allareaaroundHolz__densuggestingthataspecificsitewasusedbylargenumbersofichthyosaursrepeatedlyovertime.Theembryosarequiteadvan__dintheirphysicaldevelopment;theirpaddlesforexamplearealreadywellformed.Onespecimenisevenpreservedinthebirthc____.Inadditiontheshalecontainsthere__insof__nynewbornsthatarebetween20and30incheslong.Whyarethereso__nypregnantfe__lesandyoungatHolz__denwhentheyaresorareelsewhereThequalityofpreservationisalmostun__tchedandquarryoperationsh__ebeencarriedoutcarefullywithanawarenessofthevalueofthefossils.Butthesefactorsdonotaccountfortheinterestingquestionofhowtherecametobesuchacon__ntrationofpregnantichthyosaursinaparticularpla__veryclosetotheirtimeofgivingbirth.罕见的化石记录胚胎与幼体被保存下来在化石记录中是少见的事情微小纤细的骨骼通常在石化前就被食腐肉的动物拆散了,或者被风化作用破坏掉了鱼龙比起陆地的动物有更大的几率被保存下来,因为它们作为海洋动物常生活在腐蚀性较小的环境中但是它们的石化需要一系列因素软组织的腐烂速度缓慢,很少被其他动物残食,缺少混杂、冲走小骨头的快速水流和波浪,以及相当快地被掩埋当这些因素存在时,某些地区就会变成一个充满保存完好的鱼龙化石的宝库在德国获尔兹梅登,那儿的沉积物给人们提出了一个有趣的分析案例人们在黑色的、含沥青的海洋页岩中发现了约19,000年前沉积下来的鱼龙化石几年时间内,在这些岩石中取得了数以千计的海洋爬行动物、鱼类以及无脊椎动物的标本它们的保存质量非常的好,但更令人称奇的是保存下来的育有胚胎的鱼龙化石数目在获尔兹梅登附近一个小地区的六个不同的页岩层中分别发现了育有胚胎的鱼龙化石这表明大量的鱼龙经年累月重复使用一个特定的地点那些胚胎已经发育得相当完整了比如,它们的蹼桨已经完全形成了有一个标本甚至被保存在产道中而且,那块页岩包含着很多在20到30英寸之间的新生幼体的化石___在其他地方那么稀少的怀孕雌兽和幼体在获尔兹梅登却那么多呢因为其保存质量几乎举世无双,采集工作的进行一直是一丝不苟的大家都认识到这些化石的价值极其珍贵,但这些因素并不能解释这个有趣的问题___在一个特定的地点会如此集中地出现即将临产的怀孕鱼龙群呢15TheNobelAcademyForthelast82yearsSwedensNobelAcademyhasdecidedwhowillre__ivetheNobelPrizeinLiteraturetherebydeterminingwhowillbeelevatedfromthegreatandtheneargreattotheimmortal.ButtodaytheAcademyiscomingunderhe__ycritici__bothfromthewithoutandfromwithin.CriticscontendthattheselectionofthewinnersoftenhaslesstodowithtruewritingabilitythanwiththepeculiarinternalpoliticsoftheAcademyandofSwedenitself.AccordingtoIng__r__orkstentheculturaleditorforoneofthecountrystwo__jornewspaperstheprizecontinuestorepresentwhatpeoplecallaverySwedishexercise:reflectingSwedishtastes.TheAcademyhasdefendeditselfagainstsuchchargesofprovinciali__initsselectionbyassertingthatitsphysicaldistan__fromthegreatliterarycapitalsoftheworldactuallyservestoprotecttheAcademyfromoutsideinfluen__s.This__ywellbetruebutcriticsrespondthatthisverydistan____yalsoberesponsiblefortheAcademysinabilitytoper__iveaccuratelyauthentictrendsintheliteraryworld.Regardlessofcon__rnsovertheselectionpro__sshoweveritseemsthattheprizewillcontinuetosurvivebothasanindicatoroftheliteraturethatwemosthighlypraiseandasanelusivegoalthatwritersseek.Iffornootherreasontheprizewillcontinuetobedesirableforthefinancialrewardsthataccompanyit;notonlyisthecashprizeitselfconsiderablebutitalsodra__ticallyincreasessalesofanauthorsbooks.诺贝尔委员会过去的82年里,瑞典的诺贝尔委员会决定了谁将获得诺贝尔文学奖,因此也就决定了谁将从伟大或近乎伟大荣升为不朽但在今天,该委员会却遭到了评选委员会内外的猛烈批评批评者们争论说评选获奖者时,起作用更大的不是真实的写作能力,而是该委员会以及瑞典特有的内部__按照瑞典两家主要报纸之一的文化版编辑Ing__r__orksten的说法,该文学奖仍然是人们所说的一种非常瑞典式的做为反映瑞典口味对于其评选过程中目光短浅的指责,该委员会辩护说,该委员会与世界几大文学之都相距遥远,实际上使该委员会免受外来的干扰这也许是对的,但批评者们反驳说,也正因为相距如此遥远,该委员会才不能准确地把握文学界的真正趋势尽管对评选程序存在着__,该文学奖将继续作为世人最为推崇的文学的标志而存在,并将继续是作家们难以达到却又会不断追逐的目标如果不考虑其他因素,而仅仅考虑与之俱来的经济利益,该奖也将继续为人所渴求这不仅因为该奖本身就是一笔可观的现金收入,而且该奖还将极大地增加一个作家的著作的销量16TheWarbetweenBritainandFranceInthelateeighteenth__nturybattlesragedinalmosteverycornerofEuropeaswellasintheMiddleEastSouthAfricatheWestIn___sandLatinAmerica.Inrealityhowevertherewasonlyone__jorwarduringthistimethewarbetweenBritainandFrance.Allotherbattleswereancillarytothislargerconflictandwereoftenatleastpartiallyrelatedtoitsantagonistsgoalsandstrategies.FrancesoughttotaldominationofEurope.ThisgoalwasobstructedbyBritishindependen__andBritainseffortsthroughoutthecontinenttothwartNapoleon;throughtreatiesBritainbuiltcoalitionsnotdissimilarincon__pttotodaysNATOguaranteeingBritishparticipationinall__jorEuropeanconflicts.Thesetwoantagonistswerepoorly__tchedinsofarastheyhadveryunequalstrengths:FrancewaspredominantonlandBritainatsea.TheFrenchknewthatshortofdefeatingtheBritishn__ytheironlyhopeofvictorywastoclosealltheportsofEuropetoBritishships.AccordinglyFrancesetouttoovercomeBritainbyextendingitsmilitarydominationfromMoscowtoLisbonfromJutlandtoCalabria.AllofthisentailedtremendousriskbecauseFrancedidnoth__ethemilitaryresour__stocontrolthismuchterritoryandstillprotectitselfand__intainorderathome.Frenchstrategistscalculatedthatan__yof150shipswouldprovidethefor__ne__ssarytodefeattheBritishn__y.Suchafor__wouldgiveFranceathree-to-twoadvantageoverBritain.Thisadvantagewasdeemedne__ssarybecauseofBritainssuperiorseaskillsandtechnologyandalsobecauseBritainwouldbefightingadefensivewarallowingittowinwithfewerfor__s.NapoleonneverlostsightofhisgoalbecauseBritainrepresentedthelastsubstantialimpedimenttohiscontrolofEurope.Ashisfor__nearedthatgoalNapoleongrewincreasinglyimpatientandbeganplanninganimmediateattack.英法战争在18世纪后期,战争爆发于欧洲大陆的几乎每一个角落,在中东、南非、西印度群岛、拉丁美洲亦都是如此然而实际上,在这一时期只有一场主要的战争,那就是英法之间的战争所有其他战争都服从于这一更大的争端,至少是与这两个对手的目标和战略有某些关联法国力图统治整个欧洲,而英国的自主及其力图在整个欧洲大陆挫败拿破仑的种种努力都是法国实现这一目标的障碍英国通过条约建立了联盟和今天北约的概念没有什么不同以保证英国插手所有欧洲的主要争端这两个对头并不是一对好对手,因为他们的力量极不均衡法兰西在陆地上称王,英格兰则在海上称霸法国人明白,如果不能击败英国海军,他们胜利的唯一希望就是让欧洲的所有港口都对英国舰船关闭于是,法国将其军事占领从莫斯科延伸到里斯本,从尤特兰延伸到卡拉布里亚,企图以此来制服英国所有这些行动包含着巨大的风险,因为法国并不具备足够的军事资源,来控制这么多地盘,同时又能保护自己,维持国内的秩序法国战略家们的算盘是,其海军若拥有150艘军舰,则将足以击跨英国海军这样的武力将使法国对英国具有3比2的优势这种优势被认为是必不可少的,因为英国人具有超群的海上技能和技术,并且打的是一场防御战争,使它能以少胜多拿破仑从未忘却他的目标,因为英国是他统治全欧的最后一个重大的障碍随着他的力量越来越靠近这个目标,拿破仑变得越来越不耐烦起来,开始策划立即攻击17EvolutionofSleepSleepisveryancient.Intheelectroen__phalographicsenseweshareitwithallthepri__tesandalmostalltheother__m__lsandbirds:it__yextendbackasfarasthereptiles.Thereissomeeviden__thatthetwotypesofsleepdreaminganddreamlessdependonthelife-styleoftheani__landthatpredatorsarestatisticallymuchmorelikelytodreamthanpreywhichareinturnmuchmorelikelytoexperien__dreamlesssleep.Indreamsleeptheani__lispowerfullyimmobilizedandre__rkablyunresponsivetoexternalstimuli.Dreamlesssleepismuchshallowerandweh__eallwitnessedcatsordogscockingtheirearstoasoundwhenapparentlyfastasleep.Thefactthatdeepdreamsleepisrareamongpreytodayseemsclearlytobeaproductofnaturalselectionandit__kessensethattodaywhensleepishighlyevolvedthestupidani__lsarelessfrequentlyimmobilizedbydeepsleepthanthe__artones.ButwhyshouldtheysleepdeeplyatallWhyshouldastateofsuchdeepimmobilizationeverh__eevolvedPerhapsoneusefulhintabouttheoriginalfunctionofsleepistobefoundinthefactthatdolphinsandwhalesandaquatic__m__lsingeneralseemtosleepverylittle.Thereisbyandlargenopla__tohideintheo__an.Coulditbethatratherthanincreasinganani__lsvulnerabilitythefunctionofsleepistodecreaseitWilseWebboftheUniversityofFloridaandRayMeddisofLondonUniversityh__esuggestedthistobethecase.Itiscon__ivablethatani__lswhoaretoostupidtobequietontheirowninitiativeareduringperiodsofhighriskimmobilizedbytheimplacablearmofsleep.Thepointseemsparticularlyclearfortheyoungofpredatoryani__ls.Thisisaninterestingnotionandprobablyatleastpartlytrue.睡眠的进化睡眠是古老的从脑电图上看,我们人类和所有灵长目动物以及几乎所有的哺乳动物和鸟类都一样需要睡眠;甚至爬行类动物也有睡眠有证据显示,有梦睡眠和无梦睡眠这两种类型的睡眠取决于该动物的生活方式从统计上看,食肉动物比被捕食动物有更多的有梦睡眠,而被捕食动物更多地无梦睡眠动物在有梦睡眠时,被有效地解除动作能力,并且对外界__缺乏反应无梦睡眠则要浅得多我们都看到过猫和狗在显然的酣睡中,有一点响动耳朵就会竖起来被捕食动物很少有深度的有梦睡眠,这看来显然是自然选择的结果而且这一点是有道理的当睡眠高度进化以后,愚笨的动物比聪明的动物更少在深度睡眠状态下丧失动作能力但是动物___要进入深度睡眠呢___这样的无动作状态也会进化出来呢海豚、鲸鱼以及水生哺乳动物睡眠都极少,这一事实可以给睡眠的根本功能提供有用的线索海洋中是没有藏身之处的会不会是这样,睡眠不但不增加动物受伤害的可能性,反而是减少了这种可能性呢佛罗里达大学的WilseWebb和伦敦大学的RayMeddis认为情况就是如此可以想像得出,在危险的时刻,那些由于太愚笨而不能自动保持安静的动物,会不由自主地变得动弹不得这一点在食肉动物的幼兽身上表现得特别明显这是一个很有意思的看法,它至少部分是正确的18ModernAmericanUniversitiesBeforethe1850stheUnitedStateshadanumberof__allcollegesmostofthemdatingfromcolonialdays.Theywere__allchurchconnectedinstitutionswhosepri__rycon__rnwastoshapethemoralcharacteroftheirstudents.ThroughoutEuropeinstitutionsofhigherlearninghaddevelopedbearingtheancientnameofuniversity.InGermanyadifferentkindofuniversityhaddeveloped.TheGer__nuniversitywascon__rnedpri__rilywithcreatingandspreadingknowledgenotmorals.Betweenmid__nturyandtheendofthe1800smorethanninethousandyoungAmericansdissatisfiedwiththeirtrainingathomewenttoGermanyforadvan__dstudy.Someofthemreturnedtobecomepresidentsofvenerablecolleges--HarvardYaleColumbia--andtransformthemintomodernuniversities.Thenewpresidentsbrokealltieswiththechurchesandbroughtinanewkindoffaculty.Professorswerehiredfortheirknowledgeofasu__ectnotbecausetheywereoftheproperfaithandhadastrongarmfordiscipliningstudents.Thenewprinciplewasthatauniversitywastocreateknowledgeaswellaspassitonandthiscalledforafacultycomposedofteacher-scholars.Drillingandlearningbyrotewererepla__dbytheGer__nmethodoflecturinginwhichtheprofessorsownresearchwaspresentedinclass.GraduatetrainingleadingtothePh.D.anancientGer__ndegreesignifyingthehighestlevelofadvan__dscholarlyattai__entwasintrodu__d.Withtheestablishmentoftheseminarsystemgraduatestudentslearnedtoquestion____yzeandconducttheirownresearch.Atthesametimethenewuniversitygreatlyexpandedinsizeandcourseofferingsbreakingcompletelyoutoftheoldconstrictedcurriculumof__the__ticsclassicsrhetoricandmusic.ThepresidentofHarvardpioneeredtheelectivesystembywhichstudentswereabletochoosetheirowncoursesofstudy.Thenotionof__jorfieldsofstudyemerged.Thenewgoalwasto__ketheuniversityrelevanttotherealpursuitsoftheworld.Payingcloseheedtothepracticalneedsofsocietythenewuniversitiestrainedmenandwomentoworkatitstaskswithengineeringstudentsbeingthemostcharacteristicofthenewregime.Studentswerealsotrainedaseconomistsarchitectsagriculturalistssocialwelfareworkersandteachers.现代美国大学19世纪50年代以前美国有一些小的学院,大多数成立于殖民时期它们是与教会挂钩的小机构,主要目的是培养学生的道德品行当时在欧洲各地,高等教育机构已经发展起来,用的是一个古老的名称--大学德国已经发展出一种不同类型的大学德国大学关心的主要是创造知识和传播知识,而不是道德教育从世纪中叶到世纪末,有9000多名美国青年因不满国内所受的教育而赴德深造他们中的一些人回国后成为一些知名学府--哈佛、耶鲁、哥伦比亚的校长并且把这些学府转变成了现代意义的大学新校长们断绝了和教会的关系,聘请了新型的教职员,聘用教授根据的是他们在学科方面的知识,而不是正确的信仰和约束学生的强硬手段新的原则是大学既要传播知识也要创造知识这就需要由学者型老师组成教工队伍靠死记硬背和做练习来学习的方法变为德国式的讲解方法德国式的讲解就是由教授讲授自己的研究课题通过研究生性质的学习可以获得表明最高学术造诣的古老的德国学位--__学位随着讨论课制度的建立,研究生们学会了提问、分析以及开展他们自己的研究同时,新式大学学校规模和课程设置完全突破了过去那种只有数学、经典著作、美学和音乐的狭窄课程表哈佛大学的校长率先推出选课制度,这样学生们就能选择自己的专业主修领域的概念也出现了新的目标是使大学对实际社会更有用密切__着社会上的实际需求,新的大学着意培养学生解决问题的能力工程系学生成为新式教育体制下最典型的学生学生们还被培训成为经济学家、建筑师、农学家、社会工作人员以及教师19ChildrensNumericalSkillsPeopleappeartobeborntocompute.Thenumericalskillsofchildrendevelopsoearlyandsoinexorablythatitiseasytoi__gineaninternalclockof__the__tical__turityguidingtheirgrowth.Notlongafterlearningtowalkandtalktheycansetthetablewithimpressiveaccuracy--oneknifeonespoononeforkforeachofthefivechairs.Soontheyarecapableofnotingthattheyh__epla__dfiveknivesspoonsandforksonthetableandabitlaterthatthisamountstofifteenpie__sofsilverware.H__ingthus__steredadditiontheymoveontosubtraction.Itseemsalmostreasonabletoexpectthatifachildweresecludedonadesertislandatbirthandretrievedsevenyearslaterheorshecouldenterasecond-grade__the__ticsclasswithoutanyseriousproblemsofin____ectualadjustment.Ofcoursethetruthisnotso______.This__nturytheworkofcognitivepsychologistshasilluminatedthesubtleformsofdailylearningonwhichin____ectualprogressdepends.Childrenwereobservedastheyslowlygrasped--orasthecasemightbebumpedinto--con__ptsthat_____stakeforgrantedastheyrefusedforinstan__tocon__dethatquantityisunchangedaswaterpoursfromashortstoutglassintoatallthinone.Psychologistsh__esin__demonstratedthatyoungchildrenaskedtocountthepencilsinapilereadilyreportthenumberofblueorredpencilsbutmustbecoaxedintofindingthetotal.Suchstu___sh__esuggestedthattherudimentsof__the__ticsare__steredgraduallyandwitheffort.Theyh__ealsosuggestedthattheverycon__ptofabstractnumbers-theideaofaonenessatwonessathreenessthatappliestoanyclassofo__ectsandisaprerequisitefordoinganythingmore__the__ticallyde__ndingthansettingatable-isitselffarfrominnate.儿童的数学能力人似乎生来就会计算孩子们使用数字的技能发展得如此之早和如此必然,很容易让人想象有一个内在的精确而成熟的数字钟在指导他们的成长孩子们在学会走路和说话后不久,就能以令人惊叹的准确布置桌子--五把椅子前面分别摆上一把刀、一个汤匙、一把叉子很快地,他们就能知道他们已在桌面上摆放了五把刀、五个汤匙、五把叉子没有多久,他们就又能知道这些东西加起来总共是15把银餐具如此这般地掌握了加法之后,他们又转向减法有一种设想几乎顺理成章,那就是,即使一个孩子一出生就被隔绝到荒岛上,七年后返回世间,也能直接上小学二年级的数学课,而不会碰到任何智力调整方面的大麻烦当然,事实并没有这么简单本世纪认知心理学家的工作已经揭示了智力发展所依赖的日常学习的微妙形式他们观察到孩子们缓慢掌握那些成年人认为理所当然的概念的过程,或者是孩子们偶然遇到这些概念的过程他们也观察到孩子们拒绝承认某些常识的情况比如孩子们拒绝承认当水从短而粗的瓶中倒入细而长的瓶子中时,水的数量没有变化心理学家们而后又展示一个例子,即让孩子们数一堆铅笔时,他们能顺利地报出蓝铅笔或红铅笔的数目,但却需诱导才能报出总的数目此类研究表明数学基础是经过逐渐努力后掌握的他们还表示抽象的数字概念,如可表示任何一类物品并且是在做比摆桌子有更高数学要求的任何事时都必备的
一、
二、三意识,远远不是天生就具备的20TheHistoricalSignifican__ofAmericanRevolutionThewaysofhistoryaresointricateandthemotivationsofhu__nactionssocomplexthatitisalwayshazardoustoattempttorepresenteventscoveringanumberofyearsamultiplicityofpersonsanddistantlocalitiesastheexpressionofonein____ectualorsocialmovement;yetthehistoricalpro__sswhichculminatedintheas__ntofTho__sJeffersontothepresidencycanberegardedastheoutstandingexamplenotonlyofthebirthofanewwayoflifebutofnationali__asanewwayoflife.TheAmericanRevolutionrepresentsthelinkbetweentheseventeenth__nturyinwhichmodernEnglandbecameconsciousofitselfandtheawakeningofmodernEuropeattheendoftheeighteenth__ntury.It__yseemstrangethatthe__rchofhistoryshouldh__ehadtocrosstheAtlanticOceanbutonlyintheNorthAmericancoloniescouldastruggleforciviclibertyleadalsotothefoundationofanewnation.Hereinthepopularrisingagainstatyrannicalgover__entthefruitsweremorethanthesecuringofafreerconstitution.Theyincludedthegrowthofanationborninlibertybythewillofthepeoplenotfromtherootsofcommondes__ntageographicentityortheambitionsofkingordynasty.WiththeAmericannationforthefirsttimeanationwasbornnotinthedimpastofhistorybutbeforetheeyesofthewholeworld.美国__的历史意义___进程是如此错综复杂,人类行为的动机是如此令人费解,以至于想把那些时间跨度大,涉及人数多,空间范围广的__描述成为一个智者或一场____的表现的企图是危险的然而以托马斯·杰弗逊登上总统宝座为__的那一段历史过程可以被视为一个特殊的例子在这段历史时期里不仅诞生了新的生活方式,而且____成为了一种新的生活方式美国__战争成为联结17世纪现代英格兰的自我意识和18世纪末现代欧洲的觉醒的纽带___行程需要跨越大西洋,这看起来似乎有些奇怪,但却只有在北美殖民地为民权和自由的斗争才能导致新国家的建立这里,____的民众起义的成果不仅是获得一个包含更多自由的宪法,还包括了一个依照人民的意愿诞生在自由中的国家的成长这个国家不是基于血缘、地理、君主或王朝的野心由于有了美国,第一次一个国家的诞生不是发生在历史模糊的过去,而是在全世界人们的眼前21TheOriginofSportsWhendidsportbeginIfsportisinessen__playtheclaimmightbe__dethatsportismucholderthanhu__nkindforasweallh__eobservedthebeastsplay.Dogsandcatswrestleandplayballgames.Fishesandbirdsdan__.Theapesh__e______pleasurablegames.Frolickinginfantsschoolchildrenplayingtagand_____armwrestlersaredemonstratingstrongtransgenerationalandtransspeciesbondswiththeuniverseofani__ls-pastpresentandfuture.Youngani__lsparticularlytumblechaserunwrestlemockimitateandlaughorsoitseemstothepointofdelightedexhaustion.Theirplayandoursappearstoservenootherpurposethantogivepleasuretotheplayersandapparentlytoremoveustemporarilyfromtheanguishoflifeinearnest.Somephilosophersh__eclaimedthatourplayfulnessisthemostnoblepartofourbasicnature.Intheirgenerouscon__ptionsplayharmlesslyandexperimentallypermitsustoputourcreativefor__sfantasyandi__ginationintoaction.Playisreleasefromthetediousbattlesagainstscarcityanddeclinewhicharethein__ssantandinevitabletrage___soflife.Thisisagrandcon__ptionthatexcitesandprovokes.Theholdersofthisviewclaimthattheoriginsofourhighestaccomplishments-liturgyliteratureandlaw-canbetra__dtoaplayimpulsewhichparadoxicallyweseemostpurelyenjoyedbyyoungbeastsandchildren.Oursportsinthisratherhappynonfatalisticviewofhu__nnaturearemoresplendidcreationsofthenondatabletransspeciesplayimpulse.体育___体育运动开始于何时如果体育运动的本质就是游戏的话,我们就可以宣称体育运动比人类古老,因为正如我们所观察到的,野兽也进行嬉戏狗和猫会扭抱玩球,鱼和鸟翩翩起舞,猿类会进行一些简单的、愉快的游戏雀跃的幼儿,捉迷藏的学童和成年摔跤者展示出人与动物界的有力的跨越世代与物种的永恒的__--特别是幼兽,它们翻筋斗、追逐、奔跑、扭打、模仿、嬉笑或者看起来是,直到愉快地精疲力尽他们的玩耍,同我们的一样,似乎并没有别的目的而只是给游戏者以愉悦,暂时把我们从严肃生活的痛苦中拉出来一些哲学家称我们的嬉戏是我们本质中最崇高的部分依他们这些随意性很大的见解,游戏无害而且实验性地允许我们的创造力、幻想和想象发挥作用游戏让人们从永不间断亦不可避免的生活悲剧-与乏匮和衰退进行的枯燥__中得到一种解脱这是一个令人兴奋、给人启发的伟大见解这种见解的持有者宣称,我们的最高成就如宗教典礼、文学、法律___可以追溯到游戏的冲动但令人不解的是我们看到只有幼兽和小孩子才最纯粹地享受着这种冲动从这种比较豁达和非宿命的人性观来看,我们的运动是超时代、跨物种的辉煌的创造22CollectiblesCollectiblesh__ebeenapartofalmosteveryculturesin__ancienttimes.Whereassomeo__ectsh__ebeencollectedfortheirusefulnessothersh__ebeenselectedfortheiraestheticbeautyalone.IntheUnitedStatesthekindsofcollectiblescurrentlypopularrangefromtraditionalo__ectssuchasstampscoinsrarebooksandarttomorere__ntitemsofinterestlikedollsbottlesbaseballcardsandcomicbooks.Interestincollectibleshasincreasedenormouslyduringthepastdecadeinpartbecausesomecollectiblesh__edemonstratedtheirvalueasinvestments.Especiallyduringcyclesofhighinflationinvestorstrytopurchasetangiblesthatwillatleastretaintheircurrent__rketvalues.Ingeneralthemosttraditionalcollectibleswillbesoughtbecausetheyh__epreservedtheirvalueovertheyearsthereisanorganizedauction__rketforthemandtheyaremosteasilysoldintheeventthatcashisneeded.Someexamplesofthemoststablecollectiblesareold__stersChinese__ramicsstampscoinsrarebooksantiquejewelrysilverpor__lainartbywell-knownartistsautographsandperiodfurniture.Otheritemsofmorere__ntinterestincludeoldphotographrecordsold__gazinespostcardsbaseballcardsartglassdollsclassiccarsoldbottlesandcomicbooks.Theserelativelynewkindsofcollectibles__yactuallyappreciatefasterasshort-terminvestmentsbut__ynotholdtheirvalueaslong-terminvestments.On__acollectiblehashaditsinitialplayitappreciatesatafairlysteadyratesupportedbyanincreasingnumberofenthusiasticcollectorscompetingforthelimitedsupplyofcollectiblesthatbecomeincreasinglymoredifficulttolocate.收藏品从古代开始,收藏品就是文化的一部分一些物品因它们的有用性被收藏,而另一些则纯粹因为它们的美被收藏在美国,当今流行的收藏品种类从传统物件,如邮票、硬币、珍本书籍、艺术品,到更近期一些的有趣的东西,如布娃娃、瓶子、垒球卡、连环漫画册对收藏品的兴趣在过去十年中大大地增长,部分原因是一些收藏品显示出了它们的投资价值尤其在高通货膨胀时期,投资者尽量__那些至少会保持他们现有市场价值的有形资产一般来说,最传统的收藏品受青睐,因为它们多年后仍保持其价值它们拥有完善的拍卖市场,在需要现金的时候最容易被卖掉一些最稳当的收藏品是古老的画作、中国陶器、邮票、硬币、珍本书籍、古代珠宝、银器、瓷器、著名艺术家的作品、亲笔签名和有时代特征的家具其它更近期的物品有旧唱片、旧__、___、垒球卡片、彩色玻璃、布娃娃、早期汽车、古瓶和连环画册作为短期投资这些相对说来较新颖的收藏品的确可能更快地增值,但作为__投资则可能不能保值一旦一件收藏品有了它第一次交易,它便以一个相当稳定的比率增值,这个增值率受到越来越多的热情的收藏者的支持,他们为有限的而且越来越难找到的收藏品而竞争23HenryFordAlthoughHenryFordsnameiscloselyassociatedwiththecon__ptof__ssproductionheshouldre__iveequalcreditforintroducinglaborpracti__sasearlyas1913thatwouldbeconsideredadvan__devenbytodaysstandards.Safetymeasureswereimprovedandtheworkdaywasredu__dtoeighthourscomparedwiththeten-ortwelve-hourdaycommonatthetime.Inordertoaccommodatetheshorterworkdaytheentirefactorywasconvertedfromtwotothreeshifts.Inadditionsickle__esaswellasimprovedmedicalcareforthoseinjuredonthejobwereinstituted.TheFordMotorCompanywasoneofthefirstfactoriestodevelopatechnicalschooltotrainspecializedskilledlaborersandanEnglishlanguageschoolforimmigrants.Someeffortswereeven__detohirethehandicappedandprovidejobsforformerconvicts.Themostwidelyacclaimedinnovationwasthefive-dollar-a-dayminimumwagethatwasofferedinordertorecruitandretainthebestmechanicsandtodiscouragethegrowthoflaborunions.Fordexplainedthenewwagepolicyintermsofefficiencyandprofitsharing.Healsomentionedthefactthathisemployeeswouldbeabletopurchasetheautomobilesthattheyprodu__d--ineffectcreatinga__rketfortheproduct.Inordertoqualifyfortheminimumwageanemployeehadtoestablishade__nthomeanddemonstrategoodpersonalhabitsincludingsobrietythriftinessindustriousnessanddependability.Althoughsomecritici__wasdirectedatFordforinvolvinghimselftoomuchinthepersonallivesofhisemployeestherecanbenodoubtthatatatimewhenimmigrantswerebeingtakenadvantageofinfrightfulwaysHenryFordwashelping__nypeopletoestablishthemselvesinAmerica.亨利·福特尽管亨利·福特的名字和大生产的概念相连,但他在劳工保护上得到同样的赞誉,因为他早在1913年便实行了用今天的标准来衡量依然是先进的标准安全措施得到改进,日工作时间从当时普遍的10或12小时减少到8小时为了适应更短的日工作时间,整个工厂从双班变成了三班而且,病假和改善了的工伤医疗得以制度化福特汽车公司是最早建立技术学校来培训专门技工和为__开设英语学校的工厂之一公司甚至为雇佣残疾人和有前科的人而作出了一些努力最受广泛称赞的革新是实行五美元一天的最低工资其目的是招收和留住那些最好的技工并阻碍工会的发展福特从效率和利润__的角度来解释这项新的工资政策他也提到这样一个事实,他的员工可以买他们生产的汽车--这实际上是为其产品另开辟了一个市场为了够资格得到最低工资,员工必须建立一个得体的家庭并显示出良好的个人习惯,包括节制、俭省、勤勉和可靠虽然有人批评福特过多地干涉了员工的私人生活,但毫无疑问,在__们被用恶劣的方式剥削的时代,亨利·福特却帮助了许多人在美国扎下根来24PianoThean__stryofthepianocanbetra__dtotheearlykeyboardinstrumentsofthefifteenthandsixteenth__nturies--thespinetthedulcimerandthevirginal.Intheseventeenth__nturytheorganthecl__ichordandtheharpsichordbecamethechiefinstrumentsofthekeyboardgroupasupre__cythey__intaineduntilthepianosupplantedthemattheendoftheeighteenth__ntury.Thecl__ichordstonewasmetallicandneverpowerful;neverthelessbecauseofthevarietyoftonepossibletoit__nycomposersfoundthecl__ichordasympatheticinstrumentforinti__techambermusic.Theharpsichordwithitsbrightvigoroustonewasthef__oriteinstrumentforsupportingthebassofthe__allorchestraoftheperiodandforcon__rtusebutthecharacterofthetonecouldnotbevarieds__ebymechanicalorstructuraldevi__s.Thepianowasperfectedintheearlyeighteenth__nturybyaharpsichord__kerinItalythoughmusicologistspointoutseveralpreviousinstan__softheinstrument.Thisinstrumentwascalledapianoefortesoftandloudtoindicateitsdynamicversatility;itsstringswerestruckbyarecoilinghammerwithafelt-paddedhead.Thewiresweremuchhe__ierintheearlierinstruments.Aseriesofmechanicalimprovementscontinuingwellintothenineteenth__nturyincludingtheintroductionofpedalstosustaintoneortosoftenittheperfectionofametalframeandsteelwireofthefinestqualityfinallyprodu__daninstrumentcapableofmyriadtonaleffectsfromthemostdelicateharmoniestoanalmostorchestralfullnessofsoundfromaliquidsingingtonetoasharppercussivebrillian__.钢琴钢琴的家系可以追溯至15至16世纪早期的键盘乐器,包括小型拨弦琴、洋琴和维金娜琴17世纪时风琴、敲弦琴和拨弦琴成为键盘乐器类的主要成员这种至高无上的地位一直为它们所保持,直到18世纪末期钢琴将它们取代敲弦古钢琴的音调有金属的音质,缺乏雄劲然而由于它的音调变化多,许多作曲家发现对于亲切的室内乐是一种得体的乐器人们最喜欢用具备明快有力音调的拨弦古钢琴来配合当时小型管弦乐团的低音乐器以及在演奏会上演奏但它的音调难以变化,除非使用机械或构件装置18世纪早期的意大利,钢琴在一位拨琴钢琴制造者手中得到完善尽管音乐理论家们指出有更早的例子这种乐器被称为pianoeforte意大利语,柔和而响亮的,以显示它有力的多样性演奏者用一个头部带皮毡的弹击乐锤敲击琴弦更早的这种乐器之上的金属丝要重得多从此,持续到19世纪的一系列机械上的改进,包括引入踏板以维持音调或使其柔和,改善金属框架,以及使用最佳性能的钢丝,最终产生了一种具备无数音调效果的乐器这些效果涵盖了从最精致的和声到几乎全部的管弦乐音响,从明快流畅的吟唱的音调到尖锐的打击乐器的清晰动人的恢宏气势25MovieMusicAccustomedthoughwearetospeakingofthefilms__debefore1927assilentthefilmhasneverbeeninthefullsenseofthewordsilent.Fromtheverybeginningmusicwasregardedasanindispensableaccompaniment;whentheLumierefilmswereshownatthefirstpublicfilmexhibitionintheUnitedStatesinFebruary1__6theywereaccompaniedbypianoimprovisationsonpopulartunes.Atfirstthemusicplayedborenospecialrelationshiptothefilms;anaccompanimentofanykindwassufficient.Withinaveryshorttimehowevertheincongruityofplayinglivelymusictoasolemnfilmbecameapparentandfilmpianistsbegantotakesomecarein__tchingtheirpie__stothemoodofthefilm.Asmovietheatersgrewinnumberandimportan__aviolinistandperhapsa__llistwouldbeaddedtothepianistin__rtaincasesandinthelargermovietheaters__allorchestraswereformed.Foranumberofyearstheselectionofmusicforeachfilmprogramrestedentirelyinthehandsoftheconductororleaderoftheorchestraandveryoftentheprincipalqualificationforholdingsuchapositionwasnotskillortastesomuchastheownershipofalargepersonallibraryofmusicalpie__s.Sin__theconductorseldomsawthefilmsuntilthenightbeforetheyweretobeshownifindeedtheconductorwasluckyenoughtoseethemthenthemusicalarrangementwasnor__llyimprovisedinthegreatesthurry.Tohelpmeetthisdifficultyfilmdistributingcompaniesstartedthepracti__ofpublishingsuggestionsformusicalaccompaniments.In1909forexampletheEdisonCompanybeganissuingwiththeirfilmssuchindicationsofmoodaspleasantsadlively.Thesuggestionsbecamemoreexplicitandsoemergedthemusicalcuesheetcontainingindicationsofmoodthetitlesofsuitablepie__sofmusicandprecisedirectionstoshowwhereonepie__ledintothenext.__rtainfilmshadmusicespeciallycomposedforthem.ThemostfamousoftheseearlyspecialscoreswasthatcomposedandarrangedforD.W.GriffithsfilmBirthofaNationwhichwasreleasedin
1915.电影插曲尽管我们习惯于将1927年以前的电影称为无声电影,但是就无声这个词完整的意义上来说,电影从未真正的无声过,从最初开始音乐就被视为必不可少的伴奏当卢米埃尔的电影在1__6年2月美国首届影片公映展览上放映的时候,影片便用当时的流行曲临场钢琴伴奏最初,这些音乐伴奏与电影没有什么特别的关系,用什么曲子伴奏都行但在很短的时间内,为一部庄重的影片演奏快活的音乐所产生的不协调感变得显而易见,因此钢琴家们开始注意将自己的作品与影片的情调结合起来随着影剧院在数量上与重要性上的不断增长,在一些场合,除了钢琴师外,还要加上小提琴师,或许还有一位大提琴师较大的影剧院里还组成了小型的管弦乐队在很长的时间内,为各部影片选择配乐完全掌握在乐队指挥或队长手中,而通常把持这种职位的资格不是技巧或鉴赏品味,而是拥有一个大的音乐作品的个人收藏因为直到电影上映的前一天晚上乐队指挥才能看到影片如果这个指挥真正有幸能够看到影片的话,音乐安排通常是在非常匆忙的情况下临场进行的为了解决以上的困难,电影发行公司开办了为音乐伴奏印制提示单的业务例如1909年爱迪生公司开始将一些诸如喜悦的、悲伤的、活泼的之类表明影片情调特征的提示与影片一起发行这些提示逐渐变得更加具体,并且出现了包括影片情调说明、适用乐曲名称和乐曲转换点等内容的配乐说明单某些影片拥有专门为其创作的音乐这些早期特创乐谱中最著名的便是为D.W.格雷夫斯1915年上映的影片《一个国家的诞生》所创作的音乐26InternationalBusinessandCross-culturalCommunicationTheincreaseininternationalbusinessandinforeigninvestmenthascreatedaneedforexecutiveswithknowledgeofforeignlanguagesandskillsincross-culturalcommunication.Americanshoweverh__enotbeenwelltrainedineitherareaandconsequentlyh__enotenjoyedthesamelevelofsuc__ssinnegotiationinaninternationalarenaash__etheirforeigncounterparts.Negotiatingisthepro__ssofcommunicatingbackandforthforthepurposeofreachinganagreement.Itinvolvespersuasionandcompromisebutinordertoparticipateineitheronethenegotiatorsmustunderstandthewaysinwhichpeoplearepersuadedandhowcompromiseisreachedwithinthecultureofthenegotiation.In__nyinternationalbusinessnegotiationsabroadAmericansareper__ivedaswealthyandimpersonal.ItoftenappearstotheforeignnegotiatorthattheAmericanrepresentsalargemulti-million-dollarcorporationthatcanaffordtopaythepri__withoutbargainingfurther.TheAmericannegotiatorsrolebecomesthatofanimpersonalpurveyorofinfor__tionandcash.Instu___sofAmericannegotiatorsabroadseveraltraitsh__ebeenidentifiedthat__yservetoconfirmthisstereotypicalper__ptionwhileunderminingthenegotiatorsposition.Twotraitsinparticularthatcausecross-culturalmisunderstandingaredirectnessandimpatien__onthepartoftheAmericannegotiator.FurthermoreAmericannegotiatorsofteninsistonrealizingshort-termgoals.Foreignnegotiatorsontheotherhand__yvaluetherelationshipestablishedbetweennegotiatorsand__ybewillingtoinvesttimeinitforlong-termbenefits.Inordertosolidifytherelationshipthey__yoptforindirectinteractionswithoutregardforthetimeinvolvedingettingtoknowtheothernegotiator.Clearlyper__ptionsanddifferen__sinvaluesaffecttheoutcomesofnegotiationsandthesuc__ssofnegotiators.ForAmericanstoplayamoreeffectiveroleininternationalbusinessnegotiationstheymustputforthmoreefforttoimprovecross-culturalunderstanding.国际商业和跨文化交流国际贸易和海外投资的增加产生了对具有外语知识和跨文化交流技巧的经理的需求然而,美国人在这两方面未得到良好的训练,因此没有在国际谈判中象他们的外国对手一样成功谈判是为了达成协议而反复交流的过程它包括说服和妥协但是为了去进行说服和妥协,谈判者必须懂得在谈判的文化中怎样说服人和怎样达成妥协在国外的国际商务谈判中,美国人被视为富有和不带个人情感在外国谈判者看来,似乎美国人代表着一个庞大的拥有数百万资财的大企业,不用进一步地讨价还价就能出得起价钱美国谈判者的角色变成了一个没有个人感情的信息及现金的供应者对在国外的美国谈判者的研究中,我们找出了损害谈判者能力的几个特点,或许证实这个已成定式的看法尤其引起跨文化误解的两个特点是美国谈判者的直截了当和缺乏耐心此外,美国谈判者经常坚持实现短期目标,而外国的谈判者会珍视建立谈判者之间的__并愿意为__利益投入时间为了巩固这种__,他们会选择非直接的交流而不计较投入用于了解对方的时间明显地,价值观的不同和理解上的差异影响了谈判的结果和谈判者的成功与否美国人要在国际商务谈判中扮演更为有效的角色,他们就必须投入更多的努力提高跨文化的理解力27ScientificTheoriesInscien__atheoryisareasonableexplanationofobservedeventsthatarerelated.Atheoryofteninvolvesani__ginarymodelthathelpsscientistspicturethewayanobservedeventcouldbeprodu__d.Agoodexampleofthisisfoundinthekineticmoleculartheoryinwhichgasesarepicturedasbeing__deupof__ny__allparticlesthatareinconstantmotion.Ausefultheoryinadditiontoexplainingpastobservationshelpstopredicteventsthath__enotasyetbeenobserved.Afteratheoryhasbeenpublicizedscientistsdesignexperimentstotestthetheory.Ifobservationsconfirmthescientistspredictionsthetheoryissupported.Ifobservationsdonotconfirmthepredictionsthescientistsmustsearchfurther.There__ybeafaultintheexperimentorthetheory__yh__etoberevisedorrejected.Scien__involvesi__ginationandcreativethinkingaswellascollectinginfor__tionandperformingexperiments.Factsbythemselvesarenotscien__.Asthe__the__ticianJulesHenriPoincaresaidScien__isbuiltwithfactsjustasahouseisbuiltwithbricksbutacollectionoffactscannotbecalledscien__anymorethanapileofbrickscanbecalledahouse.Mostscientistsstartaninvestigationbyfindingoutwhatotherscientistsh__elearnedaboutaparticularproblem.Afterknownfactsh__ebeengatheredthescientistcomestothepartoftheinvestigationthatrequiresconsiderablei__gination.Possiblesolutionstotheproblemareformulated.Thesepossiblesolutionsarecalledhypotheses.Inawayanyhypothesisisaleapintotheunknown.Itextendsthescientiststhinkingbeyondtheknownfacts.Thescientistplansexperimentsperformscalculationsand__kesobservationstotesthypotheses.Withouthypothesisfurtherinvestigationlackspurposeanddirection.Whenhypothesesareconfirmedtheyareincorporatedintotheories.科学理论在科学中,理论是对所观察到的相关__的合理解释理论通常包含一个虚构的模型,这个模型帮助科学家构想所观察到的__是如何发生的分子运动理论便是我们能找到的一个很好的例子在这个理论中,气体被描绘成由许多不断运动的小颗粒组成一个有用的理论,除了能够解释过去的观测,还有助于预测那些未被观测到的__一个理论公开后,科学家们设计实验来检验这个理论如果观察证实了科学家的预言,这个理论则得到了验证如果观察不能证实科学家的预言,科学家就必须进一步的研究或许是实验存在错误,或许是这个理论必须被修改或抛弃科学家除了收集信息和操作实验外还需要想象能力和创/造性思维事实本身并不是科学正如数学家乔斯·亨利·波恩克尔所说科学建立在事实之上,就像房子用砖砌成一样但事实的收集不能被称作科学,就像一堆砖不能被叫作房子一样多数科学家通过找出别的科学家在一个特定问题上的所知来开始研究在收集了已知事实之后,科学家开始了研究中需要相当想像力的部分他们尔后拟订对这个问题的可行的解决方法这些可行的解决方式被称为假设在某种意义上,任何假设都是向未知的跳跃它使科学家的思维超越已知事实科学家计划实验、计算、观测以检验假定若没有假设,进一步的研究便缺乏目的和方向当假设被证实了,就成为理论的一部分28ChangingRolesofPublicEducationOneofthemostimportantsocialdevelopmentsthathelpedto__kepossibleashiftinthinkingabouttheroleofpubliceducationwastheeffectofthebabyboomofthe1950sand1960sontheschools.Inthe1920sbutespeciallyintheDepressionconditionsofthe1930stheUnitedStatesexperien__dadecliningbirthrate--everythousandwomenagedfifteentoforty-fourg__ebirthtoabout118livechildrenin1920,
89.2in1930,
75.8in1936and80in
1940.WiththegrowingprosperitybroughtonbytheSecondWorldWarandtheeconomicboomthatfollowedityoungpeople__rriedandestablishedhouseholdsearlierandbegantoraiselargerfamiliesthanhadtheirprede__ssorsduringtheDepression.Birthratesroseto102perthousandin
1946106.2in1950and118in
1955.Althougheconomicswasprobablythemostimportantdeterminantitisnottheonlyexplanationforthebabyboom.Theincreasedvaluepla__dontheideaofthefamilyalsohelpstoexplainthisriseinbirthrates.Thebabyboomersbeganstreamingintothefirstgradebythemid1940sandbecameafloodby
1950.Thepublicschoolsystemsuddenlyfounditselfovertaxed.Whilethenumberofschoolchildrenrosebecauseofwartimeandpostwarconditionsthesesameconditions__detheschoolsevenlesspreparedtocopewiththeflood.Thewartimeeconomymeantthatfewnewschoolswerebuiltbetween1940and
1945.Moreoverduringthewarandintheboomtimesthatfollowedlargenumbersofteacherslefttheirprofessionforbetter-payingjobselsewhereintheeconomy.Thereforeinthe1950sand1960sthebabyboomhitanantiquatedandinadequateschoolsystem.Consequentlythecustodialrhetoricofthe1930sandearly1940snolonger__desensethatiskeepingyouthsagedsixteenandolderoutofthelabor__rketbykeepingtheminschoolcouldnolongerbeahighpriorityforaninstitutionunabletofindspa__andstafftoteachyoungerchildrenagedfivetosixteen.Withthebabyboomthefocusofeducatorsandoflaymeninterestedineducationinevitablyturnedtowardthelowergradesandbacktobasicacademicskillsanddiscipline.Thesystemnolongerhadmuchinterestinofferingnontraditionalnewandextraservi__stoolderyouths.公共教育的角色变化一项重要的、有可能促使人们对公共教育的角色的看法发生转变的社会发展是本世纪五____的生育高峰对学校的影响在20年代,尤其是在30年代后的大萧条中,美国经历了一次出生率的下降--1920年每千名年龄在15岁至45岁的妇女生下大约118个存活婴儿,1930年__.2个,1936年
75.8个,1940年80个随着二战带来的持续繁荣以及随之而来的经济增长,年轻人比大萧条中的同龄人更早地结婚成家,而且比前辈养育更大的家庭1946年出生率上升到102%,1950年达106%,1955年达118%对于生育高峰,经济有可能是最重要的决定因素,但它并不是唯一的解释不断受到重视的家庭观念也有助于解释出生率的上升到40年代中期为止,这些生育高峰出生的孩子们开始源源不断地进入小学一年级到了1950年,就形成了一股洪流公共教育系统突然感到不堪重负了由于战时和战后的状况,使得学龄儿童人数增加,这些状况使得学校面对这股洪流更加措手不及战时经济意味着在1940年到1950年间几乎没有建立新学校而且,在战时和随后的经济增长时期,大量的教师离开岗位去别处从事报酬更为优厚的工作因此,在五____,生育高峰冲击着陈旧而不完备的学校体系这样一来,30年代以及40年代早期,监护理论就不再有意义了也就是说,通过使16岁以上的年轻人留在学校不进入劳动力市场的做法再也不是教育机构的优先考虑了因为教育机构不再能找到场地和教师来教育那些更小的5-16岁的孩子随着生育高峰,教育者和圈外人士对教育的兴趣和焦点,不可避免地转向了更低的年级和基础的学术技能和学科上这个系统不再有浓厚的兴趣给较年长的年轻人提供非传统的新式的和额外的服务29TelecommutingTelecommuting--substitutingthecomputerforthetriptothejob--hasbeenhailedasasolutiontoallkindsofproblemsrelatedtooffi__work.Forworkersitpromises_______fromtheoffi__lesstimewastedintrafficandhelpwithchild-careconflicts.For__nagementtelecommutinghelpskeephighperformersonboardminimizestardinessandabsenteei__byeliminatingcommutesallowsperiodsofsolitudeforhigh-con__ntrationtasksandprovidessche____ngflexibility.InsomeareassuchasSouthernCaliforniaandSeattleWashingtonlocalgover__entsareencouragingcompaniestostarttelecommutingprogramsinordertoredu__rush-hourcongestionandimproveairquality.Butthesebenefitsdonotcomeeasily.__kingatelecommutingprogramworkrequirescarefulplanningandanunderstandingofthedifferen__sbetweentelecommutingrealitiesandpopulari__ges.__nyworkersaresedu__dbyrosyillusionsoflifeasatelecommuter.AcomputerprogrammerfromNewYorkCitymovestothetranquilAdirondackMountainsandstaysincontactwithheroffi__viacomputer.A__nagercomesintohisoffi__threedaysaweekandworksathometheothertwo.Anaccountantstayshometocareforhersickchild;shehooksuphertelephonemodemconnectionsanddoesoffi__workbetweencallstothedoctor.Thesearepowerfuli__gesbuttheyarealimitedreflectionofreality.Telecommutingworkerssoonlearnthatitisalmostimpossibletocon__ntrateonworkandcareforayoungchildatthesametime.Beforea__rtainageyoungchildrencannotrecognizemuchlessrespectthene__ssaryboundariesbetweenworkandfamily.Additionalchildsupportisne__ssaryiftheparentistogetanyworkdone.__nagementtoomustseparatethemythfromthereality.Althoughthemediahaspaidagreatdealofattentiontotelecommutinginmostcasesitistheemployeessituationnotthe__ailabilityoftechnologythatprecipitatesatelecommutingarrangement.Thatispartlywhydespitethewidespreadpresscoveragethenumberofcompanieswithwork-at-homeprogramsorpolicyguidelinesre__ins__all.电子交通电子交通--用电脑取代上班的往返--作为对各种各样的办公室工作问题的解决办法已受到了欢迎对工__来说,它承诺不受办公室的约束,更少的时间浪费在交通上和有助于解决照看小孩的矛盾对管理者来说,电子交通有助于挽留高效率的工__,通过省去办公室与家之间的来回往返,大大减少工作拖拉和旷工,给予管理者独处的时间来完成需要高度集中精神的任务,为管理者提供灵活的时间安排在一些地区,如南加利福尼亚和西雅图、华盛顿,地方__鼓励公司开始电子交通计划以减少交通高峰时的塞车和提高空气质量但这些益处也来之不易要使电子交通成功需要仔细的计划并且理解电子交通的现实状况和流行的想象之间的区别许多工__被电子交通的美好幻想所迷惑一位电脑程序设计员从纽约市搬到了宁静的阿第伦达克山,用电脑保持与她办公室之间的__一位经理一周三天到办公室,其他两天在家工作;一位会计师在家照顾她生病的孩子,接通__调制解调器的接头,在同医生通话之余完成办公室工作这些是很有震撼力的情景,但也是对现实有限的反映电子交通者很快发现在同一时间专注工作和照看小孩几乎是不可能的在某个年龄之前,小孩子不可能意识到,更不可能尊重工作与家庭之间的界限如果家长要完成工作,就必须另外照看小孩管理阶层必须把现实同神话分开虽然传媒对电子交通投入了极大的__,但在很大程度上,是员工的实际情况而不是技术的可能性促成电子交通的安排这就是___尽管有广泛的报导,具有在家工作项目或行动纲领的公司数目依然很少的部分原因30TheOriginofRefrigeratorsBythemid-nineteenth__nturythetermi__boxhadenteredtheAmericanlanguagebuti__wasstillonlybeginningtoaffectthe___tofordinarycitizensintheUnitedStates.Thei__tradegrewwiththegrowthofcities.I__wasusedinhotelst__ernsandhospitalsandbysomeforward-lookingcitydealersinfreshmeatfreshfishandbutter.AftertheCivilWar1861-1865asi__wasusedtorefrigeratefreightcarsitalsocameintohouseholduse.Evenbefore1880halfthei__soldinNewYorkPhiladelphiaandBaltimoreandone-thirdofthatsoldinBostonandChicagowenttofamiliesfortheirownuse.Thishadbecomepossiblebecauseanewhouseholdconvenien__thei__boxaprecursorofthemodernrefrigeratorhadbeeninvented.__kinganefficienti__boxwasnotaseasyaswemightnowsuppose.Intheearlynineteenth__nturytheknowledgeofthephysicsofheatwhichwasessentialtoascien__ofrefrigerationwasrudimentary.Thecommonsensenotionthatthebesti__boxwasonethatpreventedthei__frommeltingwasofcoursemistakenforitwasthemeltingofthei__thatperformedthecooling.Neverthelessearlyeffortstoeconomizei__includedwrappingthei__inblanketswhichkeptthei__fromdoingitsjob.Notuntilneartheendofthenineteenth__nturydidinventorsachievethedelicatebalan__ofinsulationandcirculationneededforanefficienti__box.Butasearlyas1803aningeniousMarylandfarmerTho__sMoorehadbeenontherighttrack.HeownedafarmabouttwentymilesoutsidethecityofWashingtonforwhichthevillageofGeorgetownwasthe__rket__nter.Whenheusedani__boxofhisowndesigntotransporthisbutterto__rkethefoundthatcustomerswouldpassuptherapidlymeltingstuffinthetubsofhiscompe_____stopayapremiumpri__forhisbutterstillfreshandhardinneatone-poundbricks.Oneadvantageofhisi__boxmoreexplainedwasthatfarmerswouldnolongerh__etotr__elto__rketatnightinordertokeeptheirprodu__cool.冰箱的由来直到19世纪中期,冰箱这个名词才进入了美国语言,但冰仅仅只是开始影响美国普通市民的饮食冰的买卖随着城市的发展而发展冰被用在旅馆、酒馆、医院以及被一些有眼光的城市商人用于肉、鱼和黄油的保鲜内战1861-1865之后,冰被用于冷藏货车,同时也进入了民用甚至在1880年前,半数在纽约、费城和巴尔的摩销售的冰,三分之一在波士顿和芝加哥销售的冰进入家庭使用,因为一种新的家庭设备,冰箱,即现代冰箱的前身,被发明了制造一台有效率的冰箱不像我们想象的那么简单19世纪早期,关于对冷藏科学至关重要的热物理知识是很浅陋的认为最好的冰箱应该防止冰的融化这样一个普遍的观点显然是错误的,因为正是冰的融化起了制冷作用早期为节省冰的努力,包括用毯子把冰包起来,使得冰不能发挥它的作用直到近19世纪末,发明家们才成功地找到有效率的冰箱所需要的精确的隔热和循环的精确平衡但早在1803年,一位有发明天才的马里兰农场主,托马斯·莫尔,找到了正确方法他拥有一个农场,离华盛顿约20英里,那里的乔治镇村庄是集市中心当他用自己设计的冰箱运送黄油去市场时,他发现顾客们会走过装在竞争者桶里那些迅速融化的黄油而给他比市价更高的__买他仍然新鲜坚硬,整齐地切成一磅一块的黄油莫尔说他的冰箱的一个好处是使得农民们不必在夜里上路去市场以保持他们产品的低温31BritishColumbiaBritishColumbiaisthethirdlargestCanadianprovin__bothinareaandpopulation.Itisnearly
1.5timesaslargeasTexasandextends800miles1280kmnorthfromtheUnitedStatesborder.ItincludesCanadasentirewestcoastandtheislandsjustoffthecoast.MostofBritishColumbiaismountainouswithlongruggedrangesrunningnorthandsouth.Eventhecoastalislandsarethere__insofamountainrangethatexistedthousandsofyearsago.DuringthelastI__Agethisrangewasscouredbyglaciersuntilmostofitwasbeneaththesea.Itspeaksnowshowasislandsscatteredalongthecoast.Thesouthwesterncoastalregionhasahumidmild__rinecli__te.SeawindsthatblowinlandfromthewestarewarmedbyacurrentofwarmwaterthatflowsthroughthePacificOcean.Asaresultwintertemperatures__erageabovefreezingandsummersaremild.Thesewarmwesternwindsalsocarrymoisturefromtheo__an.InlandfromthecoastthewindsfromthePacificmeetthemountainbarriersofthecoastalrangesandtheRockyMountains.Astheyrisetocrossthemountainsthewindsarecooledandtheirmoisturebeginstofallasrain.Onsomeofthewesternslopesalmost200inches500cmofrainfalleachyear.MorethanhalfofBritishColumbiaishe__ilyforested.Onmountainslopesthatre__iveplentifulrainfallhugeDouglasfirsriseintoweringcolumns.Theseforestgiantsoftengrowtobeasmuchas300feet90mtallwithdiametersupto10feet3m.Morelumberisprodu__dfromthesetreesthanfromanyotherkindoftreeinNorthAmerica.Hemlockred__darandbalsamfirareamongtheothertreesfoundinBritishColumbia.英属哥伦比亚英属哥伦比亚是___的第三大省,无论是__还是人口都是如此它几乎是德克萨斯的
1.5倍,从美国边境一直向北延伸了800英里1,280公里它包括了___整个西海岸及附近岛屿大部分英属哥伦比亚多山峦绵长而粗犷的山脉贯通南北甚至那些沿海的岛屿都是那些存在于千万年前的山脉的遗迹在上一个冰河时期,这些山脉被冰河冲刷侵蚀,直到大部分山脉被淹没在海中它们的峰顶显现为沿着海岸散布的岛屿西南海岸地区有着潮湿温和的海洋性气候从太平洋来的温暖的洋流使得从西吹过内陆的海风变得温暖因此这儿冬天平均气温在零上而且夏天也不会酷热这些温暖的西风同样也从海洋带来了湿气来自太平洋的、从海岸向内陆的风遇到海岸山脉和落基山脉这些山脉屏障当气流升高跨越这些山脉时,风的温度就降低了,风中的水分形成降雨在一些朝西山坡区域每年大约有200英寸500厘米的降水大部分英属哥伦比亚密布着森林在有充足降水的斜坡,巨大的道格拉斯枞树高耸入云这些森林巨人常常长到高达300英尺90米,直径粗达10英尺3米这些树产出了比北美其他任何树都多的木材铁杉、红香椿、香脂冷杉枞都是发现于英属哥伦比亚的其它树种32BotanyBotanythestudyofplantsoccupiesapeculiarpositioninthehistoryofhu__nknowledge.For__nythousandsofyearsitwastheonefieldofawarenessaboutwhichhu__nshadanythingmorethanthevaguestofinsights.ItisimpossibletoknowtodayjustwhatourStoneAgean__storsknewaboutplantsbutfromwhatwecanobserveofpreindustrialsocietiesthatstillexistadetailedlearningofplantsandtheirpropertiesmustbeextremelyancient.Thisislogical.Plantsarethebasisofthefoodpyramidforalllivingthingsevenforotherplants.Theyh__ealwaysbeenenormouslyimportanttothewelfareofpeoplenotonlyforfoodbutalsoforclothingweaponstoolsdyesmedicinesshelterandagreat__nyotherpurposes.TribeslivingtodayinthejunglesoftheA__zonrecognizeliterallyhundredsofplantsandknow__nypropertiesofeach.Tothembotanyassuchhasnonameandisprobablynotevenrecognizedasaspecialbranchofknowledgeatall.Unfortunatelythemoreindustrializedwebecomethefartherawaywemovefromdirectcontactwithplantsandthelessdistinctourknowledgeofbotanygrows.Yeteveryonecomesunconsciouslyonana__zingamountofbotanicalknowledgeandfewpeoplewillfailtorecognizearoseanappleoranorchid.WhenourNeolithican__storslivingintheMiddleEastabout10000yearsagodiscoveredthat__rtaingrassescouldbeharvestedandtheirseedsplantedforricheryieldsthenextseasonthefirstgreatstepinanewassociationofplantsandhu__nswastaken.Grainswerediscoveredandfromthemflowedthe__rvelofagriculture:cultivatedcrops.Fromthenonhu__nswouldincreasinglytaketheirlivingfromthecontrolledproductionofafewplantsratherthangettingalittlehereandalittletherefrom__nyvarietiesthatgrewwild-andtheaccumulatedknowledgeoftensofthousandsofyearsofexperien__andinti__cywithplantsinthewildwouldbegintofadeaway.植物学植物学,即对植物的研究,在人类知识的历史中占据了特殊的地位这是人类几千年来超越模糊的认知而真正有所了解的领域之一我们今天不可能知道新石器时代的祖先们对植物到底了解多少,但我们在至今仍存在的前工业化社会观察到人类对植物及其特性的详细了解应该是非常古老的这是理所当然的植物是其他生物甚至其他植物食物金字塔的基础它们对人们的生活至关重要,不仅在食物上,而且在衣物、武器、工具、染料、药物、住所和许许多多其他的用途上至今仍生活在亚马逊河丛林中的部落确实能够辨识几百种植物并知道每一种的许多特性对他们来说,植物学没有专门的名称,甚至可能根本未被认为是一种专门知识不幸的是,工业化的程度越高,我们距直接与植物接触就越远,我们的植物学知识的增加也就越微不足道然而每个人在不知不觉中拥有大量的植物学知识,很少有人认不出玫瑰、苹果或兰花大约一万年前居住在中东的新时代的祖先们发现某些草能被收获,它们的种子下一季耕种会收获更多时,人类就迈出了人和植物之间的新关系第一大步谷子被发现后,农业的奇迹从此诞生这就是可栽培的谷物从那时起,人类越来越依赖少数可控制的作物生存,而不再是从众多的野生种类中这里获取一点,那里获取一点这样在千万年中对于野生植物的经验和密切__中积累起来的知识就开始消失了33PlanktonScatteredthroughtheseasoftheworldarebillionsoftonsof__allplantsandani__lscalledplankton.Mostoftheseplantsandani__lsaretoo__allforthehu__neyetosee.Theydriftaboutlazilywiththecurrentsprovidingabasicfoodfor__nylargerani__ls.Planktonhasbeendescribedastheequivalentofthegrassesthatgrowonthedrylandcontinentsandthecomparisonisanappropriateone.Inpotentialfoodvaluehoweverplanktonfaroutweighsthatofthelandgrasses.Onescientisthasesti__tedthatwhilegrassesoftheworldprodu__about49billiontonsofvaluablecarbohydrateseachyeartheseasplanktongeneratesmorethantwi__asmuch.Despiteitsenormousfoodpotentiallittleeffectwas__deuntilre__ntlytofarmplanktonaswefarmgrassesonland.Now__rinescientistsh__eatlastbeguntostudythispossibilityespeciallyastheseasresour__sloomevenmoreimportantasameansoffeedinganexpandingworldpopulation.Nooneyethasseriouslysuggestedthatplanktonburgers__ysoonbecomepopulararoundtheworld.Asapossiblefarmedsupplementaryfoodsour__howeverplanktonisgainingconsiderableinterestamong__rinescientists.Onetypeofplanktonthatseemstoh__egreatharvestpossibilitiesisatinyshrimplikecreaturecalledkrill.Growingtotwoorthreeincheslongkrillprovidethe__jorfoodforthegreatbluewhalethelargestani__leverinhabittheEarth.Realizingthatthiswhale__ygrowto100feetandweigh150tonsat__turityitisnotsurprisingthateachonedevoursmorethanonetonofkrilldaily.浮游生物数十亿吨的被称为浮游生物的小动物、植物散布在世界的海洋中这些小的动、植物大多太小而难以被人眼看到它们随波逐流,为许多较大的动物提供了基本的食物浮游生物曾被描述为生长在大陆陆地上的各种草类的海洋对应物这种比喻是恰当的然而就潜在的食物价值而言,浮游生物远胜于草类一位科学家曾经估计,世界上的草类每年生产大约490亿吨有用的碳水化合物,而海洋里的浮游生物每年生产的碳水化合物多于此数的两倍尽管浮游生物具备巨大的食物潜能,但直到最近人们还很少象种植草类那样付出努力养殖浮游生物现在,海洋科学家们至少已开始研究这种可能性全球人口不断扩张,海洋资源作为食品的重要性日益突出现在还没有人认真说过浮游生物汉堡会很快在世界上流行起来然而,作为一种可能养殖的补充性食物资源,浮游生物正引起了海洋科学家们相当大的兴趣一种似乎具有很大收获可能性的微小的虾状浮游生物被称为鳞虾鳞虾长至2~3英寸长时即成为地球上曾居住过的最大动物--蓝鲸的主要食物成熟的蓝鲸可以达到100英尺长,150吨重,所以每头鲸每天吞食1吨多的鳞虾一点也不让人吃惊34RaisingOystersInthepastoysterswereraisedinmuchthesamewayasdirtfarmersraisedto__toes-bytransplantingthem.Firstfarmersselectedtheoysterbedclearedthebottomofoldshellsandotherdebristhenscatteredcleanshellsabout.Nexttheyplantedfertilizedoystereggswhichwithintwoorthreeweekshatchedintolarvae.Thelarvaedrifteduntiltheyattachedthemselvestothecleanshellsonthebottom.Theretheyre__inedandintimegrewintobabyoysterscalledseedorspat.Thespatgrewlargerbydrawinginseawaterfromwhichtheyderivedmicroscopicparticlesoffood.Beforelongfarmersgatheredthebabyoysterstransplantedtheminotherwaterstospeeduptheirgrowththentransplantedthemon__moreintoanotherbodyofwatertofattenthemup.Untilre__ntlythesupplyofwildoystersandthosecrudelyfarmedweremorethanenoughtosatisfypeoplesneeds.Buttodaythedelectableseafoodisnolonger__ailableinabundan__.Theproblemhasbecomesoseriousthatsomeoysterbedsh__evanishedentirely.Fortunatelyasfarbackastheearly1900s__rinebiologistsrealizedthatifnewmeasureswerenottakenoysterswouldbecomeextinctoratbestaluxuryfood.Sotheysetupwell-equippedhatcheriesandwenttowork.Buttheydidnoth__etheproperequipmentortheskilltohandletheeggs.Theydidnotknowwhenwhatandhowtofeedthelarvae.Andtheyknewlittleaboutthepredatorsthatattackandeatbabyoystersbythemillions.Theyfailedbuttheydoggedlykeptatit.Finallyinthe1940sasignificantbreakthroughwas__de.The__rinebiologistsdiscoveredthatbyraisingthetemperatureofthewatertheycouldindu__oysterstospawnnotonlyinthesummerbutalsointhefallwinterandspring.Latertheydevelopedatechniqueforfeedingthelarvaeandrearingthemtospat.Goingstillfurthertheysuc__ededinbreedingnewstrainsthatwereresistanttodiseasesgrewfasterandlargerandflourishedinwaterofdifferentsalinitiesandtemperatures.Inadditionthecultivatedoysterstastedbetter!饲养牡蛎过去人们饲养牡蛎的方式很大程度上类似于田地里的农夫种植蕃茄--通过移植来饲养它们首先,农夫选好牡蛎苗床,清除底部的旧壳和其它杂物,然后四处撒播干净的壳接着,他们栽种已受精的牡蛎卵这些卵在2~3周内会孵化成幼贝幼贝一直漂流直到粘在苗床底部干净的壳上为止它们会呆在那儿并逐渐长成小牡蛎我们称之为种子或贝苗贝苗吸进海水中的微小生物作为食物从而越长越大不久之后,农夫将这些小牡蛎收集起来,把它们移种进其他的水域加快其生长,然后再次将它们移种进另外的水域以使其肥壮起来直到最近,野生的以及人工饲养的牡蛎完全能够满足人们的需要但是今天这种可口的海味已不再大量存在这个问题已经变得如此严重以至于一些牡蛎苗床已完全消失幸运的是,早在20世纪初期海洋生物学家们就意识到如果不采取新的措施,牡蛎将会灭绝或至少会变为一种奢侈的食品因此他们建造了装备良好的孵卵场所并开始工作但是他们尚没有适当的装置或技术来处理牡蛎卵他们不知道何时、用什么以及如何喂养幼贝他们对捕食数百万幼小牡蛎的动物天敌也所知无几他们失败了,但他们顽强地坚持了下来终于,在20世纪40年代,一个重要的突破性的进展产生了海洋生物学家发现,升高水温能够诱导牡蛎不仅在夏季也在秋季、冬季和春季里产卵后来他们发展了一项技术来喂养幼贝至其长成贝苗他们进一步成功地培养出了新的品种,可以抵抗疾病、长得更快、更大并且在不同的盐度和温度的水中都能茁壮生长此外,这些培殖出的牡蛎口感更佳!35OilRefiningAnimportantnewindustryoilrefininggrewaftertheCivilWar.Crudeoilorpetroleum--adarkthickoozefromtheearth--hadbeenknownforhundredsofyearsbutlittleusehadeverbeen__deofit.Inthe1850sSamuelM.Kiera__nufacturerinwesternPennsylvaniabegancollectingtheoilfromlocalseepagesandrefiningitintokerosene.Refininglike__eltingisapro__ssofremovingimpuritiesfromaraw__terial.Kerosenewasusedtolightlamps.Itwasacheapsubstituteforwhaleoilwhichwasbecominghardertoget.Soontherewasalargede__ndforkerosene.Peoplebegantosearchfornewsuppliesofpetroleum.ThefirstoilwellwasdrilledbyE.L.Drakearetiredrailroadconductor.In1859hebegandrillinginTitusvillePennsylvania.ThewholeventureseemedsoimpracticalandfoolishthatonlookerscalleditDrakesFolly.Butwhenhehaddrilleddownabout70feet21metersDrakestruckoil.Hiswellbegantoyield20barrelsofcrudeoiladay.NewsofDrakessuc__ssbroughtoilprospectorstothes__ne.Bytheearly1860sthesewildcattersweredrillingforblackgoldalloverwesternPennsylvania.TheboomrivaledtheCaliforniagoldrushof1848initsexcitementandWildWestatmosphere.Anditbroughtfarmorewealthtotheprospectorsthananygoldrush.Crudeoilcouldberefinedinto__nyproducts.Forsomeyearskerosenecontinuedtobetheprincipalone.Itwassoldingro__rystoresanddoor-to-door.Inthe1880srefinerslearnedhowto__keotherpetroleumproductssuchaswaxesandlubricatingoils.Petroleumwasnotthenusedto__kegasolineorheatingoil.炼油一种重要的新兴工业--炼油业在国内战争后成长起来未__的石油,或原油--一种深色的地下的稠浆--数百年来一直为大众所知,但是人们却很少使用过它在__世纪五十年代,萨缪尔·M·科尔,宾西法尼亚西部的一位制造商,开始从当地的溢出物中收集石油并将它炼成煤油与冶炼矿石一样,石油提炼是一个从未__的原料中除去杂质的过程煤油被用来点灯它是鲸油的一种便宜的替代品,而鲸油正变得越来越难以获得不久就产生了对煤油的大量需求人们开始寻找新的石油供应第一口油井为E·L·瑞克,一个退休的火车检票员所钻得1859年他开始在宾西法尼亚的泰特斯维尔钻井整个的这项冒险事业看起来是如此不现实和愚蠢以致旁观者称之为鸭子的蠢行译者注DrakesFollydrake在这里意含双关,即指瑞克的名字,又指该词的本义即鸭子但当瑞克往下钻至70英尺21米的时候,他发现了石油他的油井从此每天生产20桶原油瑞克成功的消息将石油勘探者们吸引到现场截止到19世纪60年代早期,这些冒险者为寻找黑色的金子钻探遍了整个宾西法尼亚西部这项繁荣的事业在__性和粗犷的西部气氛上可与1848年的加州淘金热相媲美,而且它为勘探者带来了远超过淘金潮的财富原油能被提炼成许多产品多年以来煤油一直是主要的一种产品它在杂货店中出售由人挨户推销19世纪八__十年代炼油者们懂得了生产其它石油产品,如蜡和润滑油那时石油还没有被用来制造汽油或采暖装置用油36PlateTectonicsandSea-floorSpreadingThetheoryofplatetectonicsdescribesthemotionsofthelithospherethecomparativelyrigidouterlayeroftheEarththatincludesallthecrustandpartoftheunderlying__ntle.Thelithosphereisdividedintoafewdozenplatesofvarioussizesandshapesingeneraltheplatesareinmotionwithrespecttooneanother.Amid-o__anridgeisaboundarybetweenplateswherenewlithospheric__terialisinjectedfrombelows.Astheplatesdivergefromamid-o__anridgetheyslideonamoreyieldinglayeratthebaseofthelithosphere.Sin__thesizeoftheEarthisessentiallyconstantnewlithospherecanbecreatedatthemid-o__anridgesonlyifanequalamountoflithospheric__terialisconsumedelsewhere.Thesiteofthisdestructionisanotherkindofplateboundary:asubductionzone.Thereoneplatedivesundertheedgeofanotherandisreincorporatedintothe__ntle.Bothkindsofplateboundaryareassociatedwithfaultsystemsearthquakesandvolcani__butthekindsofgeologicactivityobservedatthetwoboundariesarequitedifferent.Theideaofsea-floorspreadingactuallypre__dedthetheoryofplatetectonics.Initsoriginalversionintheearly1960sitdescribedthecreationanddestructionoftheo__anfloorbutitdidnotspecifyrigidlithosphericplates.ThehypothesiswassubstantiatedsoonafterwardbythediscoverythatperiodicreversalsoftheEarths__gneticfieldarerecordedintheo__aniccrust.As__g__risesunderthemid-o__anridgeferro__gneticmineralsinthe__g__become__gnetizedinthedirectionofthegeo__gneticfield.Whenthe__g__coolsandsolidifiesthedirectionandthepolarityofthefieldarepreservedinthe__gnetizedvolcanicrock.Reversalsofthefieldgiverisetoaseriesof__gneticstripesrunningparalleltotheaxisoftherift.Theo__aniccrustthusservesasa__gnetictaperecordingofthehistoryofthegeo__gneticfieldthatcanbedatedindependently;thewidthofthestripesindicatestherateofthesea-floorspreading.板块结构与海床扩展板块结构理论描述岩石圈的运动岩石圈是相对坚硬的地球外层,包括全部地壳和部分地幔岩石圈被划分为几十个大小不同形状各异的板块,一般而言这些板块都处于相对运动之中一道中海脊是板块之间的边界,在那里新的岩石圈的物质从下部注入当板块从中海脊脱离时,它们滑向在岩石圈基部较易变形的地层上因为地球的大小本质上是不变的,只有同等数量的岩石圈物质在其它地方被吞没,新的岩石圈才能生成销毁旧岩石圈的地方形成另外一种板块边界一块潜没的区域在这里,一块板块潜没到另一板块的边缘之下并结合入地幔之中两种板块边界均与地层系统、地震以及火山活动有关,但在两种边界处观察到的诸般地质活动却迥然不同海床扩展说实际上早于板块结构理论在20世纪60年代它的理论雏形中,描述了海底的生成和毁灭,但没有详细介绍坚硬的岩石圈板块这个假定不久之后为发现所证实该发现表明地球磁场周期性的逆转被记录在海洋地壳中当岩浆从中海脊下涌起的时候,岩浆中的磁铁矿物质按地磁场的方向被磁化岩浆冷却并凝固下来后,地磁场的方向和磁极被保留在磁化了的火山岩中磁场的逆转形成一系列与断层轴线平行的条形磁区这样海洋壳就扮演了磁带的角色,记录下可以鉴定时间的地磁场的历史条形磁区的宽度表明了海底扩展的速度37I__bergsI__bergsareamongnaturesmostspectacularcreationsandyetmostpeopleh__eneverseenone.Avagueairofmysteryenvelopsthem.Theycomeintobeing--somewhere--infarawayfrigidwatersamidthunderousnoiseandsplashingturbulen__whichinmostcasenoonehearsorsees.Theyexistonlyashorttimeandthenslowlywasteawayjustasunnoti__d.O__ectsofsheerestbeautytheyh__ebeencalled.Appearinginanendlessvarietyofshapesthey__ybedazzlinglywhiteorthey__ybeglassybluegreenorpurpletintedfaintlyorindarkerhues.Theyaregra__fulstatelyinspiring--incalmsunlightseas.Buttheyarealsocalledfrighteninganddangerousandthattheyare--inthenightinthefogandinstorms.Eveninclearweatheroneiswisetostayasafedistan__awayfromthem.Mostoftheirbulkishiddenbelowthewatersotheirunderwaterparts__yextendoutfarbeyondthevisibletop.Alsothey__yrolloverunexpectedlychurningthewatersaroundthem.I__bergsarepartsofglaciersthatbreakoffdriftintothewaterfloataboutawhileandfinallymelt.I__bergsafloattodayare__deofsnowflakesthath__efallenoverlongagesoftime.Theyembodysnowsthatdrifteddownhundredsor__nythousandsorinsomecases__ybeamillionyearsago.Thesnowsfellinpolarregionsandoncoldmountainswheretheymeltedonlyalittleornotatallandsocollectedtogreatdepthsovertheyearsand__nturies.Aseachyearssnowaccumulationlayonthesu_____evaporationandmeltingcausedthesnowflakesslowlytolosetheirfeatherypointsandbecometinygrainsofi__.Whennewsnowfellontopoftheoldittooturnedtoicygrains.Soblanketsofsnowandi__grainsmountedlayeruponlayerandwereofsuchgreatthicknessthattheweightoftheupperlayerscompressedthelowerones.Withtimeandpressurefromabovethe__ny__alli__grainsjoinedandchangedtolargercrystalsandeventuallythedeepercrystalsmergedintoasolid__ssofi__.冰山冰山是大自然最壮观的创造之一,但大多数人却从未看到过冰山,一种朦胧神秘的气氛笼罩着它们冰山形成于久远的、寒冷的水体中,而且伴随着雷声轰鸣般的嘈杂和水花汹涌的风暴,但却无人耳闻目睹冰山仅存在短短的一段时间就慢慢地悄无声息地融化掉冰山具有最纯粹的美,人们如是说冰山呈现出千姿百态,可能白得耀眼,或者是闪耀着蓝色、绿色或紫色的玻璃般的光芒,或浓或淡它们在平静的阳光照耀的海水中显得优雅堂皇,令人浮想联翩但是人们亦把冰山称为恐怖的和危险的它们的确如此--在夜间,雾天和风暴肆虐时即便是在晴朗的天气里,与它们保持一段安全距离也是明智的冰山的大部分体积稳藏于水下,因此其水下部分的伸展远远超过可见的顶部冰山也可能出人意料地翻滚,剧烈地搅动周围的水体冰山是冰川的一部分,从冰川断裂漂流进水中,一段时间后融化今天的冰山由多年前降落的雪花形成它们的体内是数百年,或数千年,有时甚至是数百万年前的降雪这些雪花落在极地或寒冷的山上,仅有少量融化或根本不融化,这样经过许多年或许多世纪后积累了巨大的深度由于每年的雪花积累在表面之上,蒸发和融化使得雪花慢慢失去其羽状尖端而变成微小的冰粒当新的雪花降落到旧的表面上,也变成了冰粒因而雪花覆盖层和冰粒层层堆积起来直到如此之大的厚度以致较上层的重量压缩较下层在时间和压力的作用下,许多小冰粒结合到一起变成更大的晶体,最终较底层的晶体合并成庞大而坚固的冰块38TopazTopazisahardtransparentmineral.Itisacompoundofaluminumsilicaandfluorine.Gemtopazisvaluable.Jewelerscallthisvarietyofthestoneprecioustopaz.Thebest-knownprecioustopazgemsrangeincolorfromrichyellowtolightbrownorpinkishred.Topazisoneofthehardestgemminerals.Inthemineraltableofhardnessithasaratingof8whichmeansthataknifecannotcutitandthattopazwillscratchquartz.Thegoldenvarietyofprecioustopazisquiteuncommon.Mostoftheworldstopaziswhiteorblue.Thewhiteandbluecrystalsoftopazarelargeoftenweighingthousandsofcarats.Forthisreasonthevalueoftopazdoesnotdependsomuchonitssizeasitdoeswithdiamondsand__nyotherpreciousstoneswherethevalueincreasesaboutfourtimeswitheachdoublingofweight.Thevalueofatopazislargelydeterminedbyitsquality.Butcolorisalsoimportant:bluetopazforinstan__isoftenirradiatedtodeepenandimproveitscolor.Bluetopazisoftensoldasaqua__rineandavarietyofbrownquartziswidelysoldastopaz.Thequartzismuchlessbrilliantandmoreplentifulthantruetopaz.Mostofitisavarietyofamethyst:thatheathasturnedbrown.黄水晶黄水晶是一种坚硬、透明的矿物质它是铝、硅和氟的化合物黄水晶宝石价值不菲珠宝商把这种石头称为黄玉最出名的黄玉有各种颜色如深黄色、淡棕色、浅红色等黄水晶是最坚硬的宝石矿中的一种在矿石硬度表上,它的硬度为8,这表明刀子不能割开它而它可在石英上划痕金黄色的黄玉品种非常罕见世界上大多数的黄水晶是白色或蓝色的这些白色或蓝色的黄水晶晶体很大,常常有数千克拉重由于这个原因,黄水晶的价值不像钻石和许多其它宝石那样主要依赖于其大小,重量翻一番价值即上升约四倍黄水晶的价值很大程度上取决于其品质,但颜色也很重要举例来说,蓝色的黄水晶常需放射处理以加深和改善其颜色蓝色的黄水晶常被作为海蓝宝石出售,许多种棕色石英被当作黄水晶广为贩卖石英光亮度远小于黄水晶,矿藏储量也远较黄水晶丰富大多数石英是一种紫水晶,高温使其变为棕色39TheSalinityofO__anWatersIfthesalinityofo__anwatersis____yzeditisfoundtovaryonlyslightlyfrompla__topla__.Neverthelesssomeofthese__allchangesareimportant.Therearethreebasicpro__ssesthatcauseachangeino__anicsalinity.Oneoftheseisthesubtractionofwaterfromtheo__anbymeansofevaporation-conversionofliquidwatertowatervapor.Inthis__nnerthesalinityisincreasedsin__thesaltsstaybehind.Ifthisiscarriedtotheextremeofcoursewhitecrystalsofsaltwouldbeleftbehind.Theoppositeofevaporationisprecipitationsuchasrainbywhichwaterisaddedtotheo__an.Heretheo__anisbeingdilutedsothatthesalinityisdecreased.This__yoccurinareasofhighrainfallorincoastalregionswhereriversflowintotheo__an.Thussalinity__ybeincreasedbythesubtractionofwaterbyevaporationordecreasedbytheadditionoffreshwaterbyprecipitationorrunoff.Nor__llyintropicalregionswherethesunisverystrongtheo__ansalinityissomewhathigherthanitisinotherpartsoftheworldwherethereisnotasmuchevaporation.Similarlyincoastalregionswhereriversdilutetheseasalinityissomewhatlowerthaninothero__anicareas.Athirdpro__ssbywhichsalinity__ybealteredisassociatedwiththefor__tionandmeltingofseai__.Whenseawaterisfrozenthedissolved__terialsareleftbehind.Inthis__nnerseawaterdirectlybeneathfreshlyformedseai__hasahighersalinitythanitdidbeforethei__appeared.Ofcoursewhenthisi__meltsitwilltendtodecreasethesalinityofthesurroundingwater.IntheWeddellSeaAntarcticathedensestwaterintheo__ansisformedasaresultofthisfreezingpro__sswhichincreasesthesalinityofcoldwater.Thishe__ywatersinksandisfoundinthedeeperportionsoftheo__ansoftheworld.海水盐度如果我们分析海水的盐度,会发现地区间只有轻微的变化,然而有些小的变化是重要的导致海洋的盐度变化的基本过程有三个,其中之一是通过蒸发的方式即把液态水转化为水蒸气来减少海洋中的水分这样由于盐留了下来,所以盐度增大当然,如果这种方式走向极端,将会余下白色的盐晶体与蒸发相反的是降水,如降雨,由此水被加入海中,海水被稀释,从而盐度降低这种情形会发生在大量降雨的地区,或江河入海岸处因此,盐度通过蒸发减少水分而上升或通过降水或径流增加淡水成分而下降一般来说,在阳光很强烈的热带地区,海水的盐度略高于世界上其它没有热带那样多的蒸发的地区同理,在江河稀释海水的海岸地带,海水盐度略低于其它海区第三个可以变更盐度的过程与海洋中冰的形成和融化有关海水冻结时,溶于其中的物质被留了下来这样,在新形成的海水冰面的正__的海水比在冰形成之前有更高的盐度当然,当冰融化的时候,会降低周围水中的盐度在南极洲边缘的威德尔海中,结冰过程增加低温海水的盐度,从而形成了浓度最大的海水这些大密度的海水下沉,可以在世界海洋的深水域发现40Cohesion-tensionTheoryAtmosphericpressurecansupportacolumnofwaterupto10metershigh.Butplantscanmovewatermuchhigher;thesequoiatreecanpumpwatertoitsverytopmorethan100metersabovetheground.Untiltheendofthenineteenth__nturythemovementofwaterintreesandothertallplantswasamystery.Somebotanistshypothesizedthattheliving__llsofplantsactedaspumps.But__nyexperimentsdemonstratedthatthestemsofplantsinwhichallthe__llsarekilledcanstillmovewatertoappreciableheights.Otherexplanationsforthemovementofwaterinplantsh__ebeenbasedonrootpressureapushonthewaterfromtherootsatthebottomoftheplant.Butrootpressureisnotnearlygreatenoughtopushwatertothetopsoftalltrees.Furthermoretheconiferswhichareamongthetallesttreesh__eunusuallylowrootpressures.Ifwaterisnotpumpedtothetopofatalltreeandifitisnotpushedtothetopofatalltreethenwe__yask:howdoesitgetthereAccordingtothecurrentlyac__ptedcohesion-tensiontheorywaterispulledthere.Thepullonarisingcolumnofwaterinaplantresultsfromtheevaporationofwateratthetopoftheplant.Aswaterislostfromthesu_____ofthele__esanegativepressureortensioniscreated.Theevaporatedwaterisrepla__dbywatermovingfrominsidetheplantinunbrokencolumnsthatextendfromthetopofaplanttoitsroots.Thesamefor__sthatcreatesu_____tensioninanysampleofwaterareresponsibleforthe__intenan__oftheseunbrokencolumnsofwater.Whenwaterisconfinedintubesofvery__allborethefor__sofcohesiontheattractionbetweenwatermoleculesaresogreatthatthestrengthofacolumnofwatercompareswiththestrengthofasteelwireofthesamediameter.Thiscohesivestrengthpermitscolumnsofwatertobepulledtogreatheightswithoutbeingbroken.内聚压力理论大气压能够支持10米高的水柱,但植物可将水送得更高美洲红杉就能把水泵到地面以上100多米高的树顶直到19世纪末,水在树木和其它高大植物中的输送还是一个谜一些植物学家假定植物中的活细胞充当了水泵的角色但许多实验表明细胞都已死亡的植物茎干仍能将水输送到相当可观的高度对于植物中输送水的其它解释都基于根压--植物底端的根对水的推动但根压完全不足以将水推到树顶况且,最高树木中的松柏只有很低的根压如果水不是被泵到高树的树顶,也不是被推到树顶,那么我们会问它是怎样到达树顶的呢根据目前为人们所接受的内聚压力的理论,水是被拉到上面去的一株植物中作用于一个正在升高的水柱之上的拉力来自该植物顶部水的蒸发由于水从叶子表面丧失,一个负压力,或张力就得以产生蒸发出去的水被植物里流动的水代替这些水形成水柱从植物顶端一直延伸到根部在任何水样中造成表面张力的力支持着这些不断的水柱当水被限制在内径很小的管道中时,内聚压力水分子之间的相互吸引力是如此之大以致一支水柱的强度相当于一根直径相同的钢丝的强度这种内聚压力使得水柱被拉到非常高的地方而不会断裂41AmericanBlackBearsAmericanblackbearsappearinavarietyofcolorsdespitetheirname.Intheeasternpartoftheirrangemostofthesebearsh__eshinyblackfurbutinthewesttheygrowbrownredorevenyellowcoats.Tothenorththeblackbearisactuallygrayorwhiteincolor.Eveninthesamelitterbothbrownandblackfurredbears__ybeborn.Blackbearsarethe__allestofallAmericanbearsranginginlengthfromfivetosixfeetweighingfromthreehundredtofivehundredpounds.Theireyesandearsare__allandtheireyesightandhearingarenotasgoodastheirsenseof__ell.Likeallbearstheblackbearistimidclumsyandrarelydangerousbutifattackedmostcanclimbtreesandcovergroundatgreatspeeds.Whenangryorfrighteneditisaformidableenemy.Blackbearsfeedonle__esherbsrootsfruitberriesinsectsfishandevenlargerani__ls.Oneofthemostinterestingcharacteristicsofbearsincludingtheblackbearistheirwintersleep.Unlikesquirrelswoodchucksand__nyotherwoodlandani__lsbearsdonotActuallyhibernate.Althoughthebeardoesnoteatduringthewintermonthssustainingitselffrombodyfatitstemperaturere__insalmostnor__landitbreathesregularlyfourorfivetimesperminute.Mostblackbearslivealoneex__ptduring__tingseason.Theyprefertoliveinc__eshollowlogsordensethickets.AlitterofonetofourcubsisborninJanuaryorFebruaryafteragestationperiodofsixtoninemonthsandtheyre__inwiththeirmotheruntiltheyarefullygrownoraboutoneandahalfyearsold.Blackbearscanliveaslongasthirtyyearsinthewildandevenlongeringamepreservessetasideforthem.美国黑熊美国黑熊虽然被叫做黑熊但却有各种各样的颜色在它们生活区域的东部,大部分黑熊长有富有光泽的黑毛,但在西部,他们则长着棕色、红色甚至是黄色的毛在北部,黑熊其实长着灰色或白色的毛就是在一胎所生的小熊中,都可能混杂棕毛和黑毛黑熊是所有美洲熊中最小的,5~6英尺长,300~500磅重它们的眼睛和耳朵都很小,他们的视力和听觉不如嗅觉那样好像所有的熊一样,黑熊胆小,笨拙,很少具有危险性但如果受到攻击,大部分黑熊会以很快的速度爬上树和奔跑当发怒或受惊吓时,黑熊会成为可怕的对手黑熊以树叶、草、树根、水果、浆果、昆虫、鱼,甚至更大的动物为食熊类,包括黑熊的最有趣的一个特点是他们的冬眠与松鼠、旱獭和其它别的林地动物不同,熊并不真正地冬眠虽然熊在冬天的几个月中不吃东西,靠体内脂肪维持生命,但它们的体温保持正常,并有规律地一分钟呼吸4或5次除交配季节外,大多数黑熊独自生活他们喜欢住在洞里、空心的大木头里或茂密的树丛里经过6到9个月的怀孕期后一胎1~4个小熊在1月或2月出生它们同母熊住在一起,直到它们完全长大,即1岁半左右黑熊在野外可以活到长达30年,在专门的保护区中甚至能活得更长42Coal-firedPowerPlantsTheinventionoftheincandes__ntlightbulbbyTho__sA.Edisonin1879createdade__ndforacheapreadily__ailablefuelwithwhichtogeneratelargeamountsofelectricpower.Coalseemedtofitthebillanditfueledtheearliestpowerstationswhichweresetupattheendofthenineteenth__nturybyEdisonhimself.Asmorepowerplantswereconstructedthroughoutthecountrytherelian__oncoalincreased.Sin__theFirstWorldWarcoal-firedpowerplantsh__eaccountedforabouthalfoftheelectricityprodu__dintheUnitedStateseachyear.In1986suchplantshadacombinedgeneratingcapacityof2__000megawattsandconsumed83per__ntofthenearly900milliontonsofcoalminedinthecountrythatyear.Giventheun__rtaintyinthefuturegrowthofnuclearpowerandinthesupplyofoilandnaturalgascoal-firedpowerplantscouldwellprovideupto70per__ntoftheelectricpowerintheUnitedStatesbytheendofthe__ntury.Yetinspiteofthefactthatcoalhaslongbeenasour__ofelectricityand__yre__inonefor__nyyearscoalrepresentsabout80per__ntofUnitedStatesfossil-fuelreservesithasactuallyneverbeenthemostdesirablefossilfuelforpowerplants.Coalcontainslessenergyperunitofweightthannaturalgasoroil;itisdifficulttotransportanditisassociatedwithahostofenviro__entalissuesamongthemacidrain.Sin__thelate1960sproblemsofemissioncontrolandwastedisposalh__esharplyredu__dtheappealofcoal-firedpowerplants.Thecostofamelioratingtheseenviro__entalproblemsalongwiththerisingcostofbuildingafacilityaslargeandcomplexasacoal-firedpowerplanth__ealso__desuchplantslessattractivefromapurelyeconomicperspective.Changesinthetechnologicalbaseofcoal-firedpowerplantscouldrestoretheirattractivenesshowever.Whereassomeofthesechangesareevolutionaryandareintended__inlytoincreasetheproductivityofexistingplantscompletelynewtechnologiesforburningcoalcleanlyarealsobeingdeveloped.火力发电厂托马斯·爱迪生1879年发明的白炽灯导致对便宜、易得、可生产大量电能的燃料的需求煤似乎符合这个要求,并成为第一批电厂的燃料正是爱迪生本人在19世纪末建造了第一批电厂全国到处兴建电厂时,对煤的依赖加深了自第一次世界大战以来,美国每年约有一半的电力是以煤为燃料的电厂提供的1986年这些电厂的总发电能力达到28,900千瓦并且消耗了当年全国开采的九亿吨煤的83%考虑到核能发展以及石油、天然气供应中的不确定因素,到本世纪末,火力发电厂仍可能为美国提供多达70%的电力然而,尽管煤__以来一直是电力的原料之一并且可能会继续如此煤占美国化石燃料储量的80%,它却不是电厂的理想燃料煤的单位能量含量低于石油和天然气,而且会导致包括酸雨在内的一系列环境问题从1960年以来,排放控制和垃圾处理的问题极大地削弱了燃煤电厂的魅力由于减轻这些环境问题需要大量资金,而且建造庞大复杂的燃煤电厂的费用不断上涨,也使得这些电厂从经济角度上不具备吸引力改变火力发电厂的基础技术却可能恢复它们的吸引力虽然某些技术改进是渐进的,其目的只是提高现有电厂的生产率,但人们正在__全新的清洁燃煤的技术43StatisticsThereweretwowidelydivergentinfluen__sontheearlydevelopmentofstatisticalmethods.Statisticshadamotherwhowasdedicatedtokeepingorderlyrecordsofgover__entalunitsstateandstatisticscomefromthesameLatinrootstatusandagentle__nlygamblingfatherwhoreliedon__the__ticstoincreasehisskillatplayingtheoddsingamesofchan__.Theinfluen__ofthemotherontheoffspringstatisticsisrepresentedbycountingmeasuringdescribingtabulatingorderingandthetakingof__nsuses--allofwhichledtomoderndescriptivestatistics.Fromtheinfluen__ofthefathercamemoderninferentialstatisticswhichisbasedsquarelyontheoriesofprobability.Descriptivestatisticsinvolvestabulatingdepictinganddescribingcollectionsofdata.Thesedata__ybequantitativesuchasmeasuresofheightin____igen__orgradelevel--variablesthatarecharacterizedbyanunderlyingcontinuum--orthedata__yrepresentqualitativevariablessuchas___college__jororpersonalitytype.Large__ssesofdatamustgenerallyundergoapro__ssofsum__rizationorreductionbeforetheyarecomprehensible.Descriptivestatisticsisatoolfordescribingorsum__rizingorreducingtocomprehensibleformthepropertiesofanotherwiseunwieldy__ssofdata.Inferentialstatisticsisafor__lizedbodyofmethodsforsolvinganotherclassofproblemsthatpresentgreatdifficultiesfortheunaidedhu__nmind.Thisgeneralclassofproblemscharacteristicallyinvolveattemptsto__kepredictionsusingasampleofobservations.Forexampleaschoolsuperintendentwishestodeterminetheproportionofchildreninalargeschoolsystemwhocometoschoolwithoutbreakfasth__ebeenvaccinatedforfluorwhatever.H__ingalittleknowledgeofstatisticsthesuperintendentwouldknowthatitisunne__ssaryandinefficienttoquestioneachchild:theproportionfortheentiredistrictcouldbeesti__tedfairlyaccuratelyfromasampleofasfewas100children.Thusthepurposeofinferentialstatisticsistopredictoresti__techaracteristicsofapopulationfromaknowledgeofthecharacteristicsofonlyasampleofthepopulation.统计学统计方法的早期发展受到两种截然不同的影响统计学有一个母亲,她致力于井井有条地记录__机构的文件国家和统计学这两个词源于同一个拉丁语词根,status,还有一个有绅士般的赌博父亲,他依靠数学来提高赌技,以便在几率的游戏中取胜母亲对其子女统计学的影响表现在计数、测量、描述、制表、归类和人口普查所有这些导致了现代描述统计学的诞生由于父亲的影响则产生了完全基于概率论原理的现代推理统计学描述统计学涉及对所收集数据的制表、制图和描述这些数据可以是数量性的数据,如高度、智商、或者是层级性的数据--具有连续性的变量--或数据也可以代表性质变量,如性别、大学专业或性格类型等等数量庞大的数据通常必须经过概括或删减的程序才能为人所理解描述统计学____一个工具,它对极其庞杂的数据进行描述、概括或删减,使其变成能为人理解的东西推理统计学是一套已定形了的方法体系,它解决的是光凭人脑极难解决的另一类问题这类问题的显著特点是试图通过取样调查来作出预测例如,有一位教育督察想知道在一个庞大的学校系统中,不吃早饭就上学的学生、已经做过防感冒免疫的学生,或其它任何类型的学生占多大比例若具备一些统计学的知识,这位督察应明白,询问每个孩子是没有必要而且没有效率的,只要用100个孩子为样本,他就可以相当精确地得出这些孩子占整个学区的比例了因此,推理统计学的目的就是通过了解一个群体中一些样本的特性,从而对整个群体的特性进行推测和估算44ObtainingFreshWaterfromI__bergsThecon__ptofobtainingfreshwaterfromi__bergsthataretowedtopopulatedareasandaridregionsoftheworldwason__treatedasajokemoreappropriatetocartoonsthanreallife.Butnowitisbeingconsideredquiteseriouslyby__nynationsespeciallysin__scientistsh__ewarnedthatthehu__nra__willoutgrowitsfreshwatersupplyfasterthanitrunsoutoffood.Glaciersareapossiblesour__offreshwaterthathasbeenoverlookeduntilre__ntly.Three-quartersoftheEarthsfreshwatersupplyisstilltiedupinglaciali__areservoirofuntappedfreshwatersoimmensethatitcouldsustainalltheriversoftheworldfor1000years.Floatingontheo__anseveryyearare7659trillionmetrictonsofi__encasedin10000i__bergsthatbreakawayfromthepolari__capsmorethanninetyper__ntofthemfromAntarctica.Hugeglaciersthatstretchovertheshallowcontinentalshelfgivebirthtoi__bergsthroughouttheyear.I__bergsarenotlikeseai__whichisformedwhentheseaitselffreezesrathertheyareformedentirelyonlandbreakingoffwhenglaciersspreadoverthesea.Astheydriftawayfromthepolarregioni__bergssometimesmovemysteriouslyinadirectionoppositetothewindpulledbysubsu_____currents.Becausetheymeltmoreslowlythan__allerpie__sofi__i__bergsh__ebeenknowntodriftasfarnorthas35degreessouthoftheequatorintheAtlanticOcean.Tocorralthemandsteerthemtopartsoftheworldwheretheyareneededwouldnotbetoodifficult.Thedifficultyarisesinothertechnical__tterssuchasthepreventionofrapidmeltinginwarmercli__tesandthefunnelingoffreshwatertoshoreingreatvolume.Butevenifthei__bergslosthalfoftheirvolumeintowingthewatertheycouldprovidewouldbefarcheaperthanthatprodu__dbydesalinizationorremovingsaltfromwater.从冰山中获取淡水把冰山拖到世界上人口稠密的地区和干旱地带,再从中获取淡水,这个想法曾一度被认为是一个笑话,更适合于卡通画,而非现实生活然而现在,许多国家正相当认真地考虑这件事情,特别是在科学家们发出警告之后科学家们认为人类将在耗尽粮食之前首先耗尽淡水资源冰川是一个直到最近以前一直被忽视的可能的淡水源全球四分之三的淡水还锁在冰川的冰块中冰川就是一个蓄水池,其中未__的淡水量是如此巨大,足够支持全世界的江河1000年每年有7,659万亿公吨冰漂流在海洋中它们包含在10,000座从极地冰帽中断裂出来的冰山中这些冰山的90%以上来自南极一年四季里,覆盖在浅层大陆架上的巨大冰川生成了众多冰山冰山和海水的冰不同,后者是海水自身结冰形成的,而冰山则完全是在陆地上形成的当冰川伸展到海水中时,冰山就断裂下来当漂离极地地区时,冰山有时会在底层洋流的推动下颇为神秘地逆风__由于冰山比小块的冰融化要慢,因此有的冰山在大西洋中向北飘到了赤道以南35°的地方把冰山蓄拦起来并拖到世界上需要它们的地方将不会太困难有困难的是其它的技术事宜比如,如何防止冰山在较暖的气候中迅速融化以及如何把大量的淡水收集到岸上去但是,即便在拖的过程中冰山失去了一半体积,这样做也远比从海水中脱盐取得淡水便宜45TheSour__ofEnergyAsum__ryofthephysicalandchemicalnatureoflifemustbeginnotontheEarthbutintheSun;infactattheSunsvery__nter.Itisherethatistobefoundthesour__oftheenergythattheSunconstantlypoursoutintospa__aslightandheat.Thisenergyisliberatedatthe__nteroftheSunasbillionsuponbillionsofnucleiofhydrogenatomscollidewitheachotherandfusetogethertoformnucleiofheliumandindoingsoreleasesomeoftheenergythatisstoredinthenucleiofatoms.TheoutputoflightandheatoftheSunrequiresthatsome600milliontonsofhydrogenbeconvertedintoheliumintheSuneverysecond.ThistheSunhasbeendoingforseveralthousandsofmillionsofyears.ThenuclearenergyisreleasedattheSuns__nterashigh-energygam__radiationaformofelectro__gneticradiationlikelightandradiow__esonlyofverymuchshorterw__elength.Thisgam__radiationisabsorbedbyatomsinsidetheSuntobereemittedatslightlylongerw__elengths.Thisradiationinitsturnisabsorbedandreemitted.AstheenergyfiltersthroughthelayersofthesolarinterioritpassesthroughtheX-raypartofthespectrumeventuallybecominglight.Atthisstageithasreachedwhatwecallthesolarsu_____andcanescapeintospa__withoutbeingabsorbedfurtherbysolaratoms.Avery__allfractionoftheSunslightandheatisemittedinsuchdirectionsthatafterpassingunhinderedthroughinterplanetaryspa__ithitstheEarth.能量的来源概说生命的物理和化学特性必须始于太阳--确切地说,是太阳的核心,而非地球能量来自太阳的核心在这里,太阳不停地以光和热的形式向空间倾泻出能量数十亿计的氢原子核在太阳的核心碰撞并且聚变生成氦在此过程中一部分原本储存于原子核中的能量被释放出来太阳所产生的光和热需要每秒将六亿吨氢转化为氦这样的转化在太阳中已经持续几十亿年了核能在太阳的核心被释放为高能的伽马射线这是一种电磁射线,就象光波和无线电波一样,只是波长要短得多这种伽玛射线被太阳内的原子所吸收,然后重新释放为波长稍长一些的光波这新的射线再次被吸收,而后释放在能量由太阳内部一层层渗透出来的过程中,它经过了光谱中X射线部分,最后变成了光在此阶段,能量到达我们所称的太阳表层,并且离散到空间而不再被太阳原子所吸收只有很小一部分太阳的光和热由此方向释放出来,并且未被阻挡,穿越星空,来到地球46VisionHu__nvisionlikethatofotherpri__teshasevolvedinanarborealenviro__ent.Inthedensecomplexworldofatropicalforestitismoreimportanttoseewellthantodevelopanacutesenseof__ell.Inthecourseofevolutionmembersofthepri__telineh__eacquiredlargeeyeswhilethesnouthasshrunktogivetheeyeanunimpededview.Of__m__lsonlyhu__nsandsomepri__tesenjoycolorvision.Theredflagisblacktothebull.Horsesliveinamonochromeworld.Lightvisibletohu__neyeshoweveroccupiesonlyaverynarrowbandinthewholeelectro__gneticspectrum.Ultr__ioletraysareinvisibletohu__nsthoughantsandhoneybeesaresensitivetothem.Hu__nsh__enodirectper__ptionofinfraredraysunliketherattlesnakewhichhasre__ptorstunedintow__elengthslongerthan
0.7micron.Theworldwouldlookeerilydifferentifhu__neyesweresensitivetoinfraredradiation.Theninsteadofthedarknessofnightwewouldbeabletomoveeasilyinastrangeshadowlessworldwhereo__ectsglowedwithvaryingdegreesofintensity.Buthu__neyesex__linotherways.Theyareinfactre__rkablydis__rningincolorgradation.Thecolorsensitivityofnor__lhu__nvisionisrarelysurpassedevenbysophisticatedtechnicaldevi__s.视觉人类的视觉,和其它灵长目动物的一样,是在丛林环境中进化出来的在稠密、复杂的热带丛林里,好的视觉比灵敏的嗅觉更加重要在进化过程中,灵长目动物的眼睛变大,同时鼻子变小以使视野不受阻碍在哺乳类动物中,只有人和一些灵长目动物能够分辨颜色红旗在公牛看来是黑色的,马则生活在一个单色的世界里然而,人眼可见的光在整个光谱中只占一个非常狭窄的频段人是看不到紫外线的,尽管蚂蚁和蜜蜂可以感觉到与响尾蛇不同,人也不能直接__到红外线响尾蛇的感觉器可以__波长超过
0.7微米的光线如果人能__到红外线的话,这世界看上去将十分不同,而且恐怖到那时,将与夜的黑暗相反,我们能轻易地在一个奇异的没有阴影的世界里走动任何物体都强弱不等地闪着光然而,人眼在其它方面有优越之处事实上,人眼对颜色梯度具有非凡的分辨能力普通人类的视觉__色彩的灵敏程度,甚至连精密的技术装备都很难超越47FolkCulturesAfolkcultureisa__allisolatedcohesiveconservativenearlyself-sufficientgroupthatishomogeneousincustomandra__withastrongfamilyorclanstructureandhighlydevelopedrituals.Orderis__intainedthroughsanctionsbasedinthereligionorfamilyandinterpersonalrelationshipsarestrong.Traditionisparamountandchangecomesinfrequentlyandslowly.Thereisrelativelylittledivisionoflaborintospecializedduties.Rathereachpersonisexpectedtoperformagreatvarietyoftasksthoughduties__ydifferbetweenthe___es.Mostgoodsarehand__deandsubsisten__economyprevails.Individuali__isweaklydevelopedinfolkculturesasaresocialclasses.UnalteredfolkculturesnolongerexistinindustrializedcountriessuchastheUnitedStatesandCanada.PerhapsthenearestmodernequivalentinAngloAmericaistheAmishaGer__nAmericanfarmingsectthatlargelyrenoun__stheproductsandlabors__ingdevi__softheindustrialage.InAmishareashorsedrawnbuggiesstillserveasalocaltransportationdevi__andthefaithfularenotpermittedtoownautomobiles.TheAmishs__ntralreligiouscon__ptofDemuthumilityclearlyreflectstheweaknessofindividuali__andsocialclasssotypicaloffolkculturesandthereisacorrespondingstrengthofAmishgroupidentity.RarelydotheAmish__rryoutsidetheirsect.ThereligionavarietyoftheMennonitefaithprovidestheprincipalmechani__for__intainingorders.Bycontrastapopularcultureisalargeheterogeneousgroupoftenhighlyindividualisticandconstantlychanging.Relationshipstendtobeimpersonalandapronoun__ddivisionoflaborexistsleadingtotheestablishmentof__nyspecializedprofessions.Secularinstitutionsofcontrolsuchasthepoli__andarmytakethepla__ofreligionandfamilyin__intainingorderandamoney-basedeconomyprevails.Becauseofthesecontrastspopular__ybeviewedasclearlydifferentfromfolk.Thepopularisreplacingthefolkinindustrializedcountriesandin__nydevelopingnations.Folk-__deo__ectsgivewaytotheirpopularequivalentusuallybecausethepopularitemismorequicklyorcheaplyprodu__diseasierortimes__ingtouseorleadsmoreprestigetotheowner.民间文化民间文化是小型的、孤立的、紧密的、保守的、近乎自给自足的群体,具有同样的习俗、同样的人种和强有力的家庭或部族结构以及高度发展的宗教仪式秩序由宗教或家庭的约束来维持,成员间的关系非常紧密,传统至高无上,很少有变动且变动缓慢劳动专业分工相对较少每个人都要做各类活计,尽管男女两性分工不同绝大多数物品是手工制造的,经济一般为自给自足型个人主义和社会阶层在民间文化群体中的发展十分薄弱在象美国和___这样的工业化国家里,一成不变的民间文化群体已不复存在了在当代美洲的英语区,与民间文化最相似的群体也许算是AmishAmish是美国的德裔农耕部落,他们基本上拒绝接受工业时代的大多数产品和节省劳力的设施在Amish地区,轻便马车仍是当地的交通工具,信徒们不允许拥有汽车Amish宗教中的核心观念Demut即谦卑典型地反映了在民间文化群中个人主义和阶级的不发达而与此同时,Amish对群体的认同性却十分强Amish人很少和他们宗派以外的人通婚其宗教,作为Mennonite信仰的一种,提供了维护秩序的主要机制相反,大众文化是包含不同种族的大群体,通常高度个性化而且不断在变化人际关系冷漠,劳动分工明确,由此产生了许多专门的职业世俗的控制机构,比如__和军队,取代了宗教和家庭来维持秩序,而且实行的是货币经济由于存在着这些差异,大众的与民间的可谓大相径庭在工业化国家以及许多发展中国家里,大众文化正在取代民间文化民间制造的物品正让位于大众化产品,这通常是因为大众化的物品制造起来更快、更便宜,用起来更容易、更方便或者是能给其所有者带来更多的威望48BacteriaBacteriaareextremely__alllivingthings.Whilewemeasureourownsizesininchesor__ntimetersbacterialsizeismeasuredinmicrons.Onemicronisathousandthofamillimeter:apinheadisaboutamillimeteracross.Rod-shapedbacteriaareusuallyfromtwotofourmicronslongwhileroundedonesaregenerallyonemicronindiameter.Thusifyouenlargedaroundedbacteriumathousandtimesitwouldbejustaboutthesizeofapinhead.An_____hu__n__gnifiedbythesameamountwouldbeoveramile
1.6kilometerstall.Evenwithanordinarymicroscopeyoumustlookcloselytoseebacteria.Usinga__gnificationof100timesonefindsthatbacteriaarebarelyvisibleastinyrodsordots.Onecannot__keoutanythingoftheirstructure.Usingspecialstainsonecanseethatsomebacteriah__eattachedtothemw__y-lookinghairscalledflagella.Othersh__eonlyoneflagellum.Theflagellarotatepushingthebacteriathroughthewater.__nybacterialackflagellaandcannotmoveaboutbytheirownpowerwhileotherscanglidealongoversu_____sbysomelittle-understoodmechani__.Fromthebacterialpointofviewtheworldisaverydifferentpla__fromwhatitistohu__ns.Toabacteriumwaterisasthickasmolassesistous.Bacteriaareso__allthattheyareinfluen__dbythemovementsofthechemicalmoleculesaroundthem.Bacteriaunderthemicroscopeeventhosewithnoflagellaoftenboun__aboutinthewater.Thisisbecausetheycollidewiththewatermoleculesandarepushedthiswayandthat.Moleculesmovesorapidlythatwithinatenthofasecondthemoleculesaroundabacteriumh__eallbeenrepla__dbynewones;evenbacteriawithoutflagellaarethusconstantlyexposedtoachangingenviro__ent.细菌细菌是极其微小的生物体我们用英寸或厘米来测量自己的大小,而测量细菌却要用微米一微米等于千分之一毫米针头直径大约一毫米棒状细菌通常有2~4微米长,而圆形细菌的直径一般只有1微米因此,即使你把一个圆形细菌放大1000倍,它也不过一个针头那么大可是如果把一个成年人放大1000倍,就会变成1英里或
1.6公里多高用一般的显微镜观察细菌时,你必须仔细观察才能看见它们使用100倍的显微镜时,你会发现细菌不过是隐约可见的小细棒或小点点,而它们的结构你却根本看不出来使用特殊的着色剂后,你会发现有的细菌上长着不少波状的毛发即鞭毛,而有的细菌只有一根鞭毛鞭毛的旋转可以推动细菌在水中行进不少细菌没有鞭毛,因而不能自己行进还有些细菌却能通过某些鲜为人知的机制沿物体表面滑动我们所熟知的世界在细菌眼中完全是另一个样子对于细菌来说,水就同糖浆之于人类一样稠密细菌是如此的微小,周围化学分子的一举一动都会对它们产生影响在显微镜下,细菌,甚至包括那些没有鞭毛的细菌,经常在水中跳来跳去这是因为它们与水分子相撞后,被弹向各个方向分子__很迅速,仅
0.1秒之隔,一个细菌周围的分子就会完全更新因此,即使是没有鞭毛的细菌也暴露在一个不断变化的环境中49SleepSleepispartofapersonsdailyactivitycycle.Thereareseveraldifferentstagesofsleepandtheytoooccurincycles.Ifyouarean__eragesleeperyoursleepcycleisasfollows.Whenyoufirstdriftoffintoslumberyoureyeswillrollaboutabityourtemperaturewilldropslightlyyourmuscleswillrelaxandyourbreathingwellslowandbecomequiteregular.Yourbrainw__esslowdownabittoowiththealpharhythmofratherfastw__espredominatingforthefirstfewminutes.Thisiscalledstage1sleep.Forthenexthalfhourorsoasyourelaxmoreandmoreyouwilldriftdownthroughstage2andstage3sleep.Theloweryourstageofsleepthesloweryourbrainw__eswillbe.Thenabout40to60minutesafteryouloseconsciousnessyouwillh__ereachedthedeepestsleepofall.Yourbrainw__eswillshowthelargesloww__esthatareknownasthedeltarhythm.Thisisstage4sleep.Youdonotre__inatthisdeepfourthstageallnightlongbutinsteadabout80minutesafteryoufallintoslumberyourbrainactivitylevelwillincreaseagainslightly.Thedeltarhythmwilldisappeartoberepla__dbytheactivitypatternofbrainw__es.Youreyeswillbegintodartaroundunderyourclosedeyelidsasifyouwerelookingatsomethingoccurringinfrontofyou.Thisperiodofrapideyemovementlastsforsome8to15minutesandiscalledREMsleep.ItisduringREMsleepperiodyourbodywillsoonrelaxagainyourbreathingwillgrowslowandregularon__moreandyouwillslipgentlybackfromstage1tostage4sleep-onlytoriseon__againtothesu_____ofnearconsciousnesssome80minuteslater.睡眠睡眠是人每天日常活动循环的一部分人的睡眠分几个阶段,而这些阶段也是循环发生的如果你是一个正常的睡眠者,你的睡眠循环会这样进行在你开始昏昏入睡时,你的眼睛会滚动几下,体温略有下降,肌肉放松,呼吸变得缓慢而有节奏除了开始几分钟比较快的α节奏外,脑电波也稍有减缓这被称为第一阶段睡眠在随后约半小时内,你进一步放松,进入第二和第三阶段睡眠睡眠越深入,脑电波就越缓慢大约在开始睡眠后的40到60分钟,你将进入沉睡状态这时的脑电波表现为巨大的缓波,被称为δ节奏这就是第四阶段睡眠但你并不是整夜都保持这种沉睡状态入睡后约80分钟左右,你的大脑运动水平会再度略有提高δ节奏消失,并被脑电波的运动图形取代你的眼睛会在闭着的眼睑下迅速转动,就好象你在看着眼前发生的什么事情这种迅速的眼球运动持续约8~15分钟,这一阶段睡眠被称之为快速眼动REM睡眠在REM睡眠阶段,你的肢体会很快再度放松,呼吸也再次放慢并变得有节奏,你会轻松地从第一阶段滑入第四阶段睡眠-直到大约80分钟后重新接近清醒状态50__llsandTemperature__llscannotre__inaliveoutside__rtainlimitsoftemperatureandmuchnarrowerlimits__rktheboundariesofeffectivefunctioning.Enzymesystemsof__m__lsandbirdsaremostefficientonlywithinanarrowrangearound37℃;adepartureofafewdegreesfromthisvalueseriouslyimpairstheirfunctioning.Eventhough__llscansurvivewiderfluctuationstheintegratedactionsofbodilysystemsareimpaired.Otherani__lsh__eawidertoleran__forchangesofbodilytemperature.For__nturiesithasbeenrecognizedthat__m__lsandbirdsdifferfromotherani__lsinthewaytheyregulatebodytemperature.Waysofcharacterizingthedifferen__h__ebecomemoreaccurateandmeaningfulovertimebutpopularterminologystillreflectstheolddivisionintowarmbloodedandcoldbloodedspecies;warm-bloodedincluded__m__lsandbirdswhereasallothercreatureswereconsideredcold-blooded.Asmorespecieswerestu___ditbecameevidentthatthisclassificationwasinadequate.Afen__lizardoradesertiguana--eachcold-blooded--usuallyhasabodytemperatureonlyadegreeortwobelowthatofhu__nsandsoisnotcold.Thereforethenextdistinctionwas__debetweenani__lsthat__intainaconstantbodytemperaturecalledhomeothermsandthosewhosebodytemperaturevarieswiththeirenviro__entcalledpoikilotherms.Butthisclassificationalsoprovedinadequatebecauseamong__m__lsthereare__nythatvarytheirbodytemperaturesduringhibernation.Furthermore__nyinvertebratesthatliveinthedepthsoftheo__anneverexperien__achangeinthechillofthedeepwaterandtheirbodytemperaturesre__inconstant.细胞与温度细胞只能在一定的温度范围内存活,而进一步保证它们有效工作的温度范围就更小了哺乳动物和鸟类的酶系统只能在37℃左右的很小范围内才能有效工作与此相差仅几度的温度都会大大削弱它们的工作效率尽管温度变化更大时细胞仍能存活,但机体系统的整体运行能力却被削弱了其它动物对体温的变化有更强的适应性几个世纪以来,人们就认识到哺乳动物和鸟类调节体温的方式与其它动物不同随着时间的推移,人们对这种差异的描述越来越精确和有意义,但是暖血动物和冷血动物这一古老的分类方式至今仍在大众词汇中有所反映暖血动物包括哺乳动物和鸟类,其它动物统统被视为冷血动物但是对更多物种进行的研究表明这种分类显然是不适当的美洲一种小型蜥蜴和沙漠鬣蜥同属冷血动物,但实际上它们的体温通常只比人类的体温低1~2度,因此并不是真正的冷血因此又出现了恒温动物即保持恒定体温的动物和变温动物即体温随外界环境的变化而改变的动物这一区分方式但这种分类也不恰当因为有不少哺乳动物在冬眠期间会改变体温,而许多生活在深海的无脊椎动物在寒冷的深海水域中体温并不变化,而是恒定的51__rine__m__lsSin__thereissuchanabundan__offoodintheseaitisunderstandablethatsomeoftheefficienthighlyadaptablewarm-blooded__m__lsthatevolvedonlandshouldh__ereturnedtothesea.Thosethatdidh__eflourished.Withinabout50millionyears--notimeatallgeologicallyspeaking--oneofthefourkindsof__m__lsthathasreturnedtoa__rineenviro__enthasdevelopedintothelargestofallani__lformsthewhale.Asecondkindthesealhasprodu__dwhatisprobablythegreatestpopulationoflargecarnivorous__m__lsonEarth.Thissuggeststhatthesetopdogsoftheo__anareprosperingandmultiplying.Howeversuchhasnotbeenthecaseatleastnotforthelast150years.Troublehasclosedinonthese__m__lsintheformofequallywarm-bloodedandevenmoreefficientandadaptablepredatorshu__ns.Atseaasonlandhu__nsh__enowpositionedthemselvesonthetopofthewholegreatpyramidoflifeandtheyh__ecausedseriousproblemsforthe__m__lsofthesea.Thereisa______reasonforthis.__rine__m__lsh__ethemisfortunetobeswimmingaggregatesofcommoditiesthathu__nswant:furoilandmeat.Evensotheymightnotbesovulnerabletohu__ndepredationiftheydidnotlikehu__nsreprodu__soslowly.Everyyearhu__nstakemorethan50milliontonsoffishfromtheo__answithoutcriticallydepletingthepopulationofanyspecies.Buttheslow-breeding__m__lsoftheseah__ebeenallbutwipedoutbyhu__nsseekingtosatisfytheirwantsandwhims.海洋哺乳动物既然海洋中有如此丰富的食物,一些原本在陆地生存的高效率的,适应性强的暖血型动物返回海洋生存是不难理解的那些已经返回海洋的哺乳动物种族繁荣在大约5千万年间这在地质学上不过是弹指一挥间,返回海洋的4种浦乳动物之一的鲸已成为体积最庞大的动物而另一种哺乳动物海豹,它的数量恐怕是地球上大型食肉哺乳动物中最大的这似乎表明这些海洋中的大哥大们人丁兴旺,一派繁荣景象但至少在近150年以来,事实并非如此同样是暖血动物而且效率更高、适应性更强的捕食者,人类,成为这些哺乳动物的日益迫近的威胁在陆地和海洋,人类都已处在巨大的生物金字塔的最顶端,成为所有生物的主宰,并给海洋哺乳动物带来巨大的危胁原因很简单这些哺乳动物不幸成为人类所需要的一堆游动着的商品,如皮毛、油和肉尽管如此,如果它们不象人类一样繁殖如此缓慢,它们对人类的掠夺也不会如此__为力每年人类从海洋中捕捞约5千万吨的鱼类,但这并未导致任何鱼种的灭绝但繁殖缓慢的海洋哺乳动物却因为有了一心只想满足一已私欲的人类而濒临52ChimpanzeeThemoststrikingsinglefactaboutchimpanzeesistheflexibilityoftheirsociallifethelackofanyrigidformoforganization.Itrepresentsaboutasfaradeparturefromthebaboontypeoforganizationasonecanfindamongthehigherpri__tesandservestoemphasizethegreatvarietyofpri__teadaptations.Chimpanzeesaremorehu__nthanbaboonsorrathertheyjibebetterwiththewayweliketopictureourselvesasfree-wheelingindividualswhotendtobeunpredictabledonottakereadilytoanyformofregimentationandarefrequentlycharming.Charmisrelativelyrareamongbaboons.Tworesearchersh__edescribedwhattheyfoundduringmorethaneightmonthsspentamongchimpanzeesintheirnaturalhabitattheforest:Wewerequitesurprisedtoobservethatthereisnosingledistinctsocialunitinchimpanzeesociety.Notonlyistherenofamilyorharemorganization;neitheristhereatrooporganization-thatistosaynoparticularchimpanzeeskeepper__nentlytogether.Onthecontraryindividualsmoveaboutatwillaloneorin__allgroupsbestdescribedasbandswhichsometimesformintolargeaggregations.Theyle__etheirassociatesiftheywanttoandjoinupwithnewoneswithoutconflict.Thegeneralpracti__isbestdescribedaseasycomeeasygoalthoughthereare__rtaingroup-formingtendencies.Asarulechimpanzeesmoveaboutinoneoffourtypesofband:_______lesonly;mothersandoffspringandoccasionallyafewotherfe__les;_____sandadoles__ntsofboth___esbutnomotherswithyoungandrepresentativesofallcategoriesmixedtogether.Thecompositionofbands__ychangeanumberoftimesduringthecourseofadayasindividualswanderoffandgroupssplitorcombinewithothergroups.Ontheotherhand__rtainindividualspreferoneanotherscompany.Oneoftheresearchersobservedthatfour__lesoftenroamedtogetheroverafour-monthperiodandmothersoftenassociatedwiththeirolderoffsprings.黑猩猩黑猩猩最突出的一个特征是它们社会生活的灵活性,即缺乏固定的组织形式它的这一特征与狒狒的那种组织形态间的差别,在灵长动物中最为突出由此可见灵长类动物中适应性变化的多样性黑猩猩比狒狒更接近人类,或者说它与我们心愿的自我形象更为接近自由自在,不落窠臼,不喜欢任何形式的约束并且往往魅力十足在狒狒中魅力比较罕见通过在黑猩猩的自然栖息地森林中对它们进行了8月的观察,两名研究人员得出这样结论我们注意到在黑猩猩的社会中似乎没有任何一种__的社会基本单位,这一点令我们很吃惊它们不仅没有家庭或妻妾组织,也没有团队组织,也就是说黑猩猩没有固定地生活在一起相反,每只黑猩猩随意流动,或是独自一人,或是作为最好称之为团伙的一员团伙有时会与其它团伙合并成大的聚合体它们可以随意离开同伴,并与其它黑猩猩组成新的团伙而不会产生任何纠纷把黑猩猩这一总的特性称之为来得容易去得快是最恰当不过了但它们也有一定的群体倾向性通常,黑猩猩群的构成有以下4种仅有成年雄性;母猩猩及其子女而且偶尔有几只其它的雌性猩猩;雄性和雌性的成年和未成年黑猩猩但不包括有子女的雌性黑猩猩;以及各种类型混杂在一起一天之中一个团伙的组成可能变化好几次,因为有的成员可能离开,而且群体可能会与其它群体合并另一方面,有些黑猩猩有自己喜欢的伙伴一名研究人员发现四只雄性黑猩猩在4个月中常常共同游荡,还有母亲们常与她们较年长的子女们在一起53NitinolNitinolisoneofthemostextraordinarymetalstobediscoveredthis__ntury:A______alloyofnickelandtitaniumnitinolhassomeperplexingproperties.Ametalwithamemoryitcanbe__detorememberanyshapeintowhichitisfashionedreturningtothatshapewheneveritisheated.Forexampleapie__ofnitinolwirebenttoformacirclethatisthenheatedandquenchedwillrememberthisshape.It__ythenbebentorcrumpledbutonreheatingwillviolentlyuntwistreformingitsoriginalshape.Thisre__rkableabilityiscalledShapeMemoryEffect__E;otheralloyssuchasbrassesareknowntopossessittoalimitedextent.Noonefullyunderstands__Eandnitinolre__insparticularlyperplexingforwheneveritperformsthispeculiarfeatitappearstobebreakingthelawsofthermodynamicsbyspringingbackintoshapewithgreaterfor__thanwasusedtodeformitinthefirstpla__.Butnotonlyisnitinolcapableofrememberingitalsohastheabilitytolearn.Iftheheating-cooling-crumpling-reheatingpro__ssiscarriedoutsufficientlyoftenandthemetalisalwayscrumpledinexactlythesamewaythenitinolwillnotonlyrememberitsoriginalshapebutgraduallyitlearnstorememberitscrumpledformaswellandwillbegintoreturntothesamecrumpledshapeeverytimeitiscooled.Eventuallythemetalwillcrumpleanduncrumpletotallyunaidedinresponsetochangesintemperatureandwithoutanysignofmetalfatigue.Engineersh__eprodu__dprototypeenginesthataredrivenbythefor__ofnitinolspringingfromoneshapetoanotherasitalternatelyencountershotandcoldwater.Theenergyfromthesere__rkableenginesishowevernotentirelyfree:heatenergyisrequiredtoprodu__thetemperaturedifferen__sneededtoruntheengine.Buttheoptimumtemperaturesatwhichthemetalreactscanbecontrolledbyalteringtheproportionsofnickeltotitanium;somealloyswillevenperformatroomtemperature.Thene__ssarytemperaturerangebetweenthewarmandthecoldcanbeaslittleastwelvedegrees__ntigrade.镍钛合金镍钛诺是这个世纪所发现的最不寻常的金属之一,作为镍和钛的简单的一种合金,镍钛诺具有一些令人惊叹的特征这是一种有记忆力的金属,人们可以使它记住它被塑成的任何形状,并在加热后恢复这一形状比如,一节镍钛诺线圈在加热冷却后会记住圆圈这形状随后它可能被弯折成其它形状,但一旦再次加热,就会迅速地自动恢复成最初的圆圈状这种不寻常的能力被称为形状记忆效果__E其它一些合金如黄铜在一定程度上也具有这种特性目前人们对__E这一特性尚缺乏透彻的认识,而镍钛诺尤其使人惊奇,因为每当它展现这一惊人的功能时,似乎都违背了热力学原理因为它在恢复原有形状时所释放的力比人们使它变形所施加的力大得多镍钛诺不仅有记忆力,还能学习如果加热-冷却-弯曲-再加热这一过程重复一定次数,且每次冷却后它都被丝毫不差地弯成同一形状,它不仅可以记住最初的形状,还能逐渐记住它被弯成的形状,并开始在每次冷却时恢复这一形状最终,它会自动地随温度变化而弯曲和恢复这些形状,并且没有任何疲劳迹象工程师们已制造出一些发动机样机,利用镍钛合金在交替遇热水和冷水时迅速改变形状所产生的力做推动力然而这些神奇的发动机工作时并非完全不耗能,因为必须有热能来制造温差才能使机器运转但人们可以通过改变合金中镍钛的比例来控制使它反应的最佳温度有的镍钛合金甚至能在室温下做出反应,冷暖之间的最小温差只有12℃54TreasureinSunkenShipsOfthetensofthousandsofshipsontheo__anbottomonlyahandfullessthan1per__ntcontainnegotiabletreasuresuchasgoldandjewels.Mostgiveusadifferentpri__lesstreasure--history.Asunkenshipliesintrustpreservedintheairlessenviro__entoftheseaandthoseindeepwaterareespeciallywellprotected.Nodrylandsitesanywhere--ex__ptperhapsEgyptiantombs--areinabetterstateofpreservationthanavesseldeepintheo__an.Asunkenshipthereforecanbeararewindowthroughwhichamomentintimeisglimpsed.Thisisnottoimplythatsunkenshipsarealwaysfoundintact.Mostshipsbreakuponthewaydownhitthebottomatabout100milesperhourandbecomea____ticconfusingjumble.Irecallthechagrinofanovi__diverwhoaftersu___cingfromanunderwatertourofa400-footshipaskedhisdivingbuddyWherewasthewreckIttakesexperien__toactuallyknowasunkenshipwhenoneseesit.Butno__tterwhatitsconditiononthewaydownashipdeterioratesmuchmoreslowlyasitsinksdeeperintoprotectivelayersofsandandmud.Ancientvesselsh__ebeenfoundinre__rkablygoodcondition.In1977agroupof__rinearchaeologistsexc__atinga900-year-oldwreckrecoveredengr__edglassware.Greekcoinsbronzekettlesanda__zinglyGreekjarscontainingseedsalmondsandlentils--evenaplatewithchickenbones.沉船中的宝藏在数以万计的海底沉船中,只有极少数,不到百分之一的沉船上有可流通的财富,如黄金和珠宝多数沉船提供给我们的是另一种无价的财富--历史沉船被海洋中没有空气的环境保管起来,躺在深水中的船只被保存得尤其完好大概除了埃及金字塔外,陆地上没有哪些遗迹比深海沉船保存得更完好了因此,每一只沉船便成为我们探视___一扇难得的窗户但这并不是说沉船被发现时都完好无损大多数船只在下沉过程中就已破碎,并以每小时100英里的速度撞击海底,因此成为乱糟糟的一团我至今仍记得一位潜水新手造访一艘400英尺长的海底沉船后浮出水面时的懊丧神情他问他的潜水伙伴沉船在哪儿看到沉船时能知道这是一只沉船是需要经验的但不管船在下沉时状况如何,当它下沉到海底具有保护作用的泥沙层后,船体的朽烂速度比在陆地上要慢得多人们曾在海底发现过保存异常完好的古船1977年,一群海洋考古学家们在发掘一只有900年___沉船时,找到了雕花玻璃器皿、希腊硬币、青铜水壶,并令人吃惊地发现一些盛有种子、杏仁和扁豆等东西的希腊罐子,甚至找到一个盛有鸡骨的盘子55CreatingColorsTherearetwowaystocreatecolorsinaphotograph.Onemethodcalledadditivestartswiththreebasiccolorsandaddsthemtogethertoprodu__someothercolors.Thesecondmethodcalledsubtractivestartswithwhitelightamixtureofallcolorsinthespectrumandbytakingawaysomeorallothercolorsle__estheonedesired.Intheadditivemethodseparatecoloredlightsarecombinedtoprodu__variousothercolors.Thethreeadditivepri__rycolorsaregreenredandblueeachproportionsaboutonethirdofthew__elengthsinthetotalspectrum.Mixedinvaryingproportionstheycanprodu__allcolors.Greenandredlightmixtoprodu__yellowredandbluelightmixtoprodu____gentagreenandbluemixtoprodu__cyan.Whenequalpartsofallthreeofthesepri__rycoloredbeamsoflightoverlapthemixtureappearswhitetotheeye.Inthesubtractivepro__sscolorsareprodu__dwhendyeasinpaintorcolorphotographic__terialsabsorbssomew__elengthsandsopassesononlypartofthespectrum.Thesubtractivepri__riesarecyanablulishgreen__gentaapurplishpinkandyellow;thesearethepigmentsordyesthatabsorbredgreenandbluew__elengthsrespectivelythussubtractingthemfromwhitelight.Thesedyecolorsarethecomplementarycolorstothethreeadditivepri__riesofredgreenandblue.Properlycombinedthesubtractivepri__riescanabsorballcolorsoflightproducingblack.Butmixedinvaryingproportionstheytoocanprodu__anycolorinthespectrum.Whetheraparticularcolorisobtainedbyaddingcoloredlightstogetherorbysubtractingsomelightfromthetotalspectrumtheresultlooksthesametotheeye.Theadditivepro__sswasemployedforearlycolorphotography.Butthesubtractivemethodwhilerequiringcomplexchemicaltechniqueshasturnedouttobemorepracticalandisthebasisofallmoderncolorfilms.创造颜色有两种方法可以使照片具有色彩一种叫加色法,通过把三种基本颜色相叠加以产生其它色彩另一种叫减色法,通过去除白色其实是光谱中所有颜色相混合的结果中的某些或其它所有色彩而把所需的色彩留下来在加色法中,不同颜色的光线混合以产生其它各种色彩加色法三原色是绿、红和蓝其中每一种占据总光谱中三分之一的波长这三种色彩以不同比例相叠加可以产生所有色彩绿光和红光叠加可产生黄色,红光与蓝光叠加可产生品红色,绿光与__叠加可产生青绿色当这三种原色光以相同比例叠加时,眼睛所见的就成为白色而在减色法中,染料比如在绘画颜料或彩色照相材料中吸收了部分波长而只允许分光谱通过,从而产生各种色彩减色法三原色是青绿色、品红略带紫色的粉红色和黄色;也就是可分别吸收红光、绿光和__的色料或染料,从而去除白色光中的这些色彩这些染料色是加色法的三原色红、绿、蓝的相互补充适当组合时,减色法三原色能吸收光线中的所有色彩,产生黑色但当它们以不同的比例叠加时,也能产生光谱中所有颜色不论某种颜色是通过把不同色彩的光线叠加还是把光谱中某些颜色的光去除掉而产生的,它的视觉效果是一样的早期彩色摄影采用加色法但减色法尽管需要复杂的化学技术,最终比前者更加实用,并成为现代彩色电影的基础56TheOrganicFoodsAreorganicallygrownfoodsthebestfoodchoi__sTheadvantagesclaimedforsuchfoodsoverconventionallygrownand__rketedfoodproductsarenowbeingdebated.Advocatesoforganicfoods--atermwhosemeaningvariesgreatly--frequentlyproclaimthatsuchproductsaresaferandmorenutritiousthanothers.ThegrowinginterestofconsumersinthesafetyandnutritionalqualityofthetypicalNorthAmerican___tisawelcomedevelopment.Howevermuchofthisinteresthasbeensparkedbysweepingclaimsthatthefoodsupplyisunsafeorinadequateinmeetingnutritionalneeds.Althoughmostoftheseclaimsarenotsupportedbyscientificeviden__thepreponderan__ofwritten__terialadvancingsuchclaims__kesitdifficultforthegeneralpublictoseparatefactfromfiction.Asaresultclaimsthateatinga___tconsistingentirelyoforganicallygrownfoodspreventsorcurediseaseorprovidesotherbenefitstohealthh__ebecomewidelypublicizedandformthebasisforfolklore.Almostdailythepublicisbesiegedbyclaimsforno-aging___tsnewvitaminsandotherwonderfoods.Therearenumerousunsubstantiatedreportsthatnaturalvitaminsaresuperiortosyntheticonesthatfertilizedeggsarenutritionallysuperiortounfertilizedeggsthatuntreatedgrainsarebetterthanfumigatedgrainsandthelike.Onethingthatmostorganicallygrownfoodproductsseemtoh__eincommonisthattheycostmorethanconventionallygrownfoods.Butin__nycasesconsumersaremislediftheybelieveorganicfoodscan__intainhealthandprovidebetternutritionalqualitythanconventionallygrownfoods.Sothereisrealcauseforcon__rnifconsumersparticularlythosewithlimitedincomesdistrusttheregularfoodsupplyandbuyonlyexpensiveorganicfoodsinstead.绿色食品绿色食品是最佳食物吗有人认为绿色食品比通过常规方式生产和销售的食品有更多的优越性,然而现在却有人对此提出异议绿色食品--这一词的用法非常不统一--支持者往往声称绿色食品比其它食品更安全,营养价值更高北美的消费者们越来越__他们的日常饮食是否安全和有营养这一发展趋势是好的然而这种__多半是由一些武断的说法引起的,即食物供应不安全或不能提供足够的营养尽管这些说法多数未被科学证实,但是由于大量文章支持这一观点,使得普通群众难辨真伪因此那些认为只食用绿色食品就能防治疾病或增进健康的观点便广为人知,并导致一些不科学的做法和习惯公众几乎每天都被抗衰老食品、新型维生素以及其它具有神奇功效的食物__所包围声称天然维生素优于人造维生素,受精蛋比未受精蛋的营养价值更高,未经薰蒸消毒处理的谷物比经过处理的好等等诸如此类的报道屡见不鲜,但没有一篇是经过证实的大多数绿色食品有一共同点,即它们的__高于以常规方式种植的食物但在许多情况下,如果消费者认为绿色食品能预防疾病且营养价值高于以常规方式生产的食品,那么他们被误导了如果消费者们,尤其是那些收入有限的消费者们,怀疑传统食品而只__更昂贵的绿色食品,那就值得担忧了57LighthousesThefirstn__igationallightsintheNewWorldwereprobablylanternshungatharborentran__s.Thefirstlighthousewasputupbythe__ssachusettsBayColonyin1716onLittleBrewsterIslandattheentran__toBostonHarbor.Paidforand__intainedbylightduesleviedonshipstheoriginalbeaconwasblownupin
1776.Bythentherewereonlyadozenorsotruelighthousesinthecolonies.Littleovera__nturylatertherewere700lighthouses.ThefirstlighterectedontheWestCoastinthe1850sfeaturedthesamebasicNewEnglanddesign:aCapeCoddwellingwiththetowerrisingfromthe__nterorstandingcloseby.InNewEnglandandelsewherethoughlighthousesreflectedavarietyofarchitecturalstyles.Sin__moststationsintheNortheastwerebuiltonrockyeminen__senormoustowerswerenottherule.Somewere__deofstoneandbrickothersofwoodormetal.Somestoodonpilingsorstilts;somewerefastenedtorockwithironrods.FarthersouthfromMarylandthroughtheFloridaKeysthecoastwaslowandsandy.Itwasoftenne__ssarytobuildtalltowersthere-__ssivestructureslikethe__jesticCapeHatterasNorthCarolinalighthousewhichwaslitin
1870.At190feetitisthetallestbricklighthouseinthecountry.Notwithstandingdifferen__sinappearan__andconstructionmostAmericanlighthousessharedseveralfeatures:alightlivingquartersandsometimesabellorlaterafoghorn.Theyalsohadsomethingelseincommon:akeeperandusuallythekeepersfamily.Thekeepersessentialtaskwastrimmingthelanternwickinorderto__intainasteadybrightflame.Theearliestkeeperscamefromeverywalkoflife-theywereseamenfarmersmechanicsroughmillhands-andappointmentswereoftenhandedoutbylocalcustomscommissionersaspoliticalplums.Aftertheadministrationoflighthouseswastakenoverin1852bytheUnitedStatesLighthouseBoardanagencyoftheTreasuryDepartmentthekeepercorpsgraduallybecamehighlyprofessional.灯塔在新大陆上,最初的航标灯要算那些挂在港湾入口的提灯了吧最初的灯塔是1716年由马萨诸塞湾殖民地在波士顿港入口一个叫小布罗斯特的岛上建起的这最初的灯塔是通过向船只征收买光钱来维持运作的,于1776年被炸毁那时,在各殖民地,真正的灯塔仅有十几个但过了一个世纪多一点,灯塔就增至七百多个了1850年,在西部沿海建起的首座灯塔基本上沿袭了新英格兰灯塔的设计方案,即那种中心或周围升起塔楼的典型的哥德角式房子新英格兰与其它一些地方的灯塔在建筑风格上是多样化的在东北部,灯塔大都建在石质的高地上,因此塔身不需要太高它们有砖石结构的;也有木材或金属结构的,有的灯塔建在支架上,有的则用铁条固定在岩石上在更南方的地区,从马里兰到弗罗里达礁群的海岸地势低平且多为沙质,因此高大的塔身就很必要了例如1870年在北卡罗来纳的哈特拉角建的宏伟的大灯塔,高达190英尺,是全美最高的砖结构灯塔虽然美国的灯塔在外观和结构上存在一些差异,但它们确有些共同之处,比如都有灯标、有住房、有时还有钟后来改用雾角此外,还有一个相同之处,那就是都有守塔人,通常是守塔人全家守塔人的基本工作就是修剪灯蕊,以便火焰明亮而稳定最早的守塔人来自各种行业海员、农民、技工和干粗活的这个职位通常是作为__回报由地方海关官员决定任命但在1852年后,财政部下属的美国灯塔管理委员会接管了所有灯塔,守塔人这支队伍也逐渐趋向专业化了58Ani__lsCompassesResearchersh__efoundthatmigratingani__lsuseavarietyofinnercompassestohelpthemn__igate.SomesteerbythepositionoftheSun.Othersn__igatebythestars.SomeusetheSunastheirguideduringthedayandthenswitchtostarn__igationbynight.OnestudyshowsthatthehomingpigeonusestheEarths__gneticfieldsasaguideinfindingitswayhomeandthereareindicationsthatvariousotherani__lsfrominsectstomolluskscanalso__keuseof__gneticcompasses.Itisofcourseveryusefulforamigratingbirdtobeabletoswitchtoa__gneticcompasswhencloudscovertheSun;otherwiseitwouldjusth__etolandandwaitfortheSuntocomeoutagain.EvenwiththeSunorstarstosteerbytheproblemsofn__igationaremorecomplicatedthantheymightseematfirst.Forexampleaworkerhoneybeethathasfoundarichsour__ofnectarandpollenfliesrapidlyhometothehivetoreport.Anaturalisthasdiscoveredthatthebeescoutdeliversherreportthroughacomplicateddan__inthehiveinwhichshe____stheotherworkersnotonlyhowfarawaythefoodisbutalsowhatdirectiontoflyinrelationtotheSun.ButtheSundoesnotstayinonepla__allday.AstheworkersstartouttogatherthefoodtheSun__yalreadyh__echangeditspositionintheskysomewhat.InlatertripsduringthedaytheSunwillseemtomovefartherandfarthertowardthewest.Yettheworkerbeesseemtoh__enotroubleatallinfindingthefoodsour__.Theirinnerclocks____themjustwheretheSunwillbeandtheychangetheircoursecorrespondingly.动物的罗盘研究人员已经发现迁徙性动物可以借助各种各样的体内罗盘来校正方向有些动物借助太阳的位置辨别方向,有些则依靠星星还有的白天利用太阳,晚上利用星星有研究发现信鸽以地磁场为向导来找到回家的路还有迹象表明许许多多其它生物,从昆虫到软体动物,也能利用这种磁场罗盘具有这种磁场罗盘,对候鸟来说当然非常有用,因为如果乌云遮日,它可以以磁场为向导继续飞行,否则它就只好着陆,等待太阳重新出现即使是借助太阳或星星导航,其中的学问也比它表面看起来的要复杂得多例如,一只工蜂找到了花圃蜜园,急忙飞回蜂房报信博物学家发现这只蜂探在蜂房里跳了一段极为复杂的舞,通过这段舞她不但告诉其它工蜂食物有多远,而且报告了以太阳为参照的飞行路线但太阳不会呆在天上不动当蜂群出发采食时,太阳可能已经多少改变了它在天空中的位置出发得越迟,太阳就越偏西,可这似乎没给寻找食物源的工蜂们带来任何不便它们体内的时钟告诉他们太阳应在的位置,据此它们相应地改变前进的方向59MusclesandHu__nBodyItisinthejointsofthehu__nbodythatmovementsofthebonestakepla__.Themovementitselfiscausedbythepullofsheetsandcordsofverytoughtissuecalledmuscle.Muscletissuehasthespecialabilitytoshortenitselfsothattheboneonwhichitpullshastomove.Whenmuscletissueshortensitalsobunchesup.Muscletissuecoversthebodyinsheetsandbandsthatliebetweentheskinandtheskeleton.Thebonesaretheframeworkofthebodybutthemusclesfilloutthebodyshape.Mostmusclesextendfromonebonetoanother.Whenthemusclebetweenthebonesshortensonebonehastomove.Thepointwherethemuscleisfastenedtotheu__ovingboneiscalledtheoriginofthemusclewhereasthepointwherethemuscleisnotfastenedtothebonethatistobemovediscalledtheinsertion.Sometimesthemuscleisnotattacheddirectlytothebonebuttoatoughnonstretchablecordortendonthatisattachedtothebone.Musclesdonotpush;theycanonlypull.Tobendthearmattheelbowthemuscleatthefrontoftheupperarmhastoshortenandbunchup.Tounbendthearmothermusclesinthebackofthearmh__etoshorten.Thesetwosetsofmuscles-thefrontandtheback-aresaidtoactinoppositiontoeachother.Whenonesetisworkingtheothersetisusuallyrelaxed.Buttherearetimeswhenbothofthemwork.Sometimesmusclesarecalledupontodomorethansimplypullinonedirection.They__yh__etoperformaturningmotion.Tobeabletodothisthemusclemustbeattachedtotheboneatanangle.Bypullingthemusclecancausethebonetopivot.Afewmusclesh__especialfunctions.Thediaphragmforexamplefor__sthelungstotakeinair.Thispartofbreathingisnotpri__rilyabonemovingoperation.肌肉和人体骨骼运动发生在人体的关节部位这种运动是由称为肌肉的片状或条状的强韧组织拖动而引起的肌肉组织有一种特殊的收缩能力,可以带动与之相连的骨骼肌肉在收缩的同时,也会聚成团肌肉以条状或片状形式布满全身,存在于皮肤与骨架之间骨骼是身体的支架,而肌肉则构成了人的体形大多数肌肉接两块骨头,但当肌肉收缩时只有一块骨头运动肌肉与不动骨相连的一端叫肌起端,与动骨相连的一端叫附着端有些肌肉不与骨骼直接相连,而是连着附在骨骼上的不能收缩的带状组织或腱上肌肉不能推动而只能拉动骨骼要从肘部弯曲手臂,就要收缩上臂正面的肌肉要伸直手臂,背面的肌肉就得收缩这两组肌肉,正面的和背面的,称为相反运动肌肉当一组工作时,另一组就休息但有时它们也一起工作有时我们要求肌肉不仅仅做简单的单向拖动它们需要转动但只有当肌肉与骨骼形成一定角度时,它们才能转动,从而拖动骨骼绕某个轴旋转有几块肌肉的作用较特殊,例如隔膜肌它带动肺部吸入空气呼吸基本上不是骨骼运动带动的60ColdsandAgeAcriticalfactorthatplaysapartinsus__ptibilitytocoldsisage.AstudydonebytheUniversityofMichiganSchoolofPublicHealthrevealedparticularsthatseemtoholdtrueforthegeneralpopulation.Infantsarethemostcoldriddengroup__eragingmorethansixcoldsintheirfirstyears.Boysh__emorecoldsthangirlsuptoagethree.Aftertheageofthreegirlsaremoresus__ptiblethanboysandteenagegirls__eragethreecoldsayeartoboystwo.Thegeneralinciden__ofcoldscontinuestodeclineinto__turity.Elderlypeoplewhoareingoodhealthh__easfewasoneortwocoldsannually.Oneex__ptionisfoundamongpeopleintheirtwentiesespeciallywomenwhoshowariseincoldinfectionsbecausepeopleinthisagegrouparemostlikelytoh__eyoungchildren._____swhodelayh__ingchildrenuntiltheirthirtiesandfortiesexperien__thesamesuddenincreaseincoldinfections.Thestudyalsofoundthateconomicsplaysanimportantrole.Asincomeincreasesthefrequencyatwhichcoldsarereportedinthefamilydecreases.Familieswiththelowestincomesufferaboutathirdmorecoldsthanfamiliesattheupperend.Lowerincomegenerallyfor__speopletoliveinmorecrampedquartersthanthosetypicallyoccupiedbywealthierpeopleandcrowdingincreasestheopportunitiesforthecoldvirustotr__elfrompersontoperson.Lowincome__yalsoadverselyinfluen_____t.Thedegreetowhichpoornutritionaffectssus__ptibilitytocoldsisnotyetclearlyestablishedbutaninadequate___tissuspectedofloweringresistan__generally.感冒与年龄年龄是人们是否易患感冒的一个重要因素密歇根大学公共卫生学院揭示了一些对人们普遍适用的细节婴儿期是最易感冒的时期,从出生到一周岁平均感冒六次在三周岁前,男孩比女孩感冒次数要多但三周岁后,女孩就更易感冒了十几岁的女孩年平均感冒三次,男孩则为两次一般说来,随着年龄的增长,感冒的次数也越来越少健康的老年人每年只感冒一至两次或更少但在__至三十岁之间的人尤其是妇女出现了例外他们感冒的次数有所增加,其原因在于人们通常在这一时期带养小孩那些晚育至三十几岁或四十几岁才有孩子的人,在那一时期感冒次数也会突然增加研究还发现,经济状况与感冒息息相关随着收入的增加,家庭成员的感冒次数呈下降趋势家境贫寒的人感冒次数要比最富裕的人多三分之一低收入者被迫挤住在比富人居所狭小得多的空间里拥挤的状况为感冒病菌的传播提供了条件低收入同样不利于合理的饮食结构营养不良到底对患感冒造成多大的影响目前尚不清楚,但不合理的饮食通常降低了人体的抵抗力61PotteryAncientpeople__declaypotterybecausetheyneededitfortheirsurvival.Theyusedthepotsthey__deforcookingstoringfoodandcarryingthingsfrompla__topla__.Potterywassoimportanttoearlyculturesthatscientistsnowstudyittolearnmoreaboutancientcivilizations.Themoreadvan__dthepotteryintermsofdecoration__terialsglazesand__nufacturethemoreadvan__dthecultureitself.Theartisanwho__kespotteryinNorthAmericatodayutilizeshisorherskillandi__ginationtocreateitemsthatarebeautifulaswellasfunctionaltransformingsomethingordinaryintosomethingspecialandunique.ThepotterusesoneoftheEarthsmostbasic__terialsclay.Claycanbefoundalmostanywhere.Goodpotteryclaymustbefreefromall__allstonesandotherhard__terialsthatwould__kethepottingpro__ssdifficult.MostNorthAmericanartisanpottersnowpurchasecommerciallypro__ssedclaybutsomefindtheclaytheyneedrightintheearthclosetowheretheywork.Themostimportanttoolspottersusearetheirownhands;howevertheyalsousewirelooptoolswoodenmodelingtoolsplainwireandsponges.Plainwireisusedtocutawaythefinishedpotfromitsbaseonthepotterswheel.Afterafinishedpotisdriedofallitsmoistureintheopenairitispla__dinakilnandfired.Thefirstfiringhardensthepotteryanditisthenreadytobeglazedandfiredagain.Forareaswheretheydonotwantanyglazesuchasthebottomofthepotartisanspaintonmeltedwaxthatwilllaterburnoffinthekiln.Theythenpourontheliquidglazeandletitrunovertheclaysu_______kinganykindofdecorativepatternthattheywant.陶器古代人制作陶器是因为他们的生存需要它他们用这些自制的盆盆罐罐来做饭、装食物、储运东西陶器在早期文化中占据了如此重要的地位,以致于科学家们现在通过研究陶器来获取对古代文明的更多的了解因为陶器的装饰、材料、釉彩、制作等工艺越发达就说明这种文明越发达今天,北美的陶艺匠人运用他们的技艺和想象力创造出了既美观又实用的陶艺制品,把日常用品变为独特的艺术品制陶匠人使用大地上最基本的原材料--粘土粘土几乎随处可见,但好的制陶所用的粘土必须不含小沙粒或任何硬物,否则会给制陶过程带来不便现在大多数北美制陶艺人买现成的专用陶土,也有些陶匠乐于就地取材,在作坊附近自己挖粘土制陶器最重要的工具是工匠们自己的双手,但有时他们也用些别的工具,如绳圈、木模、素线、海绵等素线的作用是当一件陶器完成后用它把陶器从转盘上的基座上切下来陶器成形后,首先要在空气中自然风干,再放到窑中焙烧第一遍焙烧使得陶器变得坚硬,下一步就是给它上釉彩,然后再焙烧陶器上有些地方不需上釉彩,像罐子底部,匠人们就在这些部位涂上蜡,一加热就会化掉然后匠人们把釉彩液体浇上陶器表面,绘制他们想要的任何图案62MimicryinPlantsPlantadaptationscanbere__rkablycomplex.__rtainspeciesoforchidsforinstan__imitatefe__lebeesotherplantslookand__elllikedeadani__lsandstillothersh__etheappearan__ofstones.Thesestrangeadaptationstoliferepresentjustafewofthesophisticatedmeansbywhichplantsenhan__theirchan__sofsurvival.Mimicryinplantsorani__lsisathreepartsystem.Thereisamodel:theani__lplantorsubstratebeinginitiated.Thereisamimic:theorgani__thatimitatesthemodel.Andthereisasignalre__iverordupe:theani__lthatcannoteffectivelydistinguishbetweenthemodelandthemimic.Mimetictraits__yincludemorphologicalstructurescolorpatternsbeh__iorsorotherattributesofthemimicthatpromoteitsresemblan__toamodel.Thatmodel__ybeeitheranunrelatedspeciesoraninani__teo__ectsuchasthebackgroundagainstwhichanorgani__spendsmostofitstime.Mimicryisnotanactivestrategyonthepartofanindividualplant;flowersdonotdeliberatelytrickorde__iveani__lsintovisitingthem.Mimicryarisesastheresultofevolutionthroughnaturalselectionandtheoccurren__ofrandomgeneticmutationsthatleadover__nygenerationstotheappearan__off__orablecharacteristics.Ifsuchtraitshelptocamouflageaplantforexampletheplantislikelytoh__easurvivaladvantageoverotherplantsthatarelesswellcamouflaged.Theplantwillle__emoredes__ndantstherebypassingtheadvantagetothenextgeneration.Fornaturalselectiontof__ortheevolutionofmimicrythemimicrymustderiveareproductiveadvantagefrommodelingitselfafteranotherorgani__oro__ect:itsfitnessmeasuredasthenumberofoffspringprodu__dthatsurviveintothenextgenerationmustbeincreasedastheresultofde__ption.植物拟态植物的适应性极为复杂某种兰花模仿雌蜂,还有些植物看上去或嗅起来象死去的动物,更有些植物具有石头的外表这些稀奇古怪的适应性不过是植物的众多求生手段中的一小部分罢了动植物的拟态包括三方面的内容一是被模仿者,动物,植物或是生态基层,二是模仿者,即那些去模拟其它东西的生物,三是上当受骗者,即不能分辨模仿者与被模仿者的动物被模仿特征包括形态结构,色彩花纹,动作习性或其它模仿者实现它与被模仿者相似的特点被模仿者可以是其它种类的生物或非生命物,如栖居地的环境拟态并非某个植物主动的策略花朵并非故意诱骗动物来访拟态是无数代自然选择和遗传变异的进化而获得的有利特征的结果比如,有些特征有利于伪装,那么具有这些特征的植物就比不具有的易于生存这种植物就会有更多的后代,并把这些特征代代相传要让自然选择惠顾模仿者的进化,模仿者必须在模仿其它生物或物体中得到繁殖优势它的适应能力,以存活至下一代的幼兽的数目来衡量,必定因为欺骗而加强了63OilandWaterTounderstandtheemulsifyingpro__sswemustfirstac__ptthescientificprinciplethatoilandwaterdonotnaturallymix.Quiteliterallytheyfindeachotherspresen__repulsive.Agoodillustrationofthis__ersionishome__deoilandvinegarsaladdressing.Whenyoushakeorbeatyoursaladdressingyoudomorethandispersetheoilthroughoutthevinegar:youalsobreakdowntheoilintodropletsminuteenoughtore__intemporarilysuspendedinthevinegarwhichfromnowonwewillcallwaterbecausethattartcondimentisineffect__inlywater.Thesecondyoustopagitatingthedressingtheoildropletsstarttocombineintounitstoolargetobesuspendedinthewaterandthusslithertheirwayupwardseparatingfromthewaterinthepro__ss.Theoilrisestothetopandthewatersinksbecauseoilhasalowerspecificdensitythanwater.Ifyouwantastableemulsionyouneedanemulsifyingagentwhichpreventstheoildropletsfromcombiningintolargerunits.Emulsifyingagentsoccurnaturallyin__nyani__lsubstan__sincludingeggyolksandmilk.Anemulsifyingagenthelpstokeeptheoilparticlesfromcombininginthreebasicways.Firsttheagentcoatstheoilservingasaphysicalbarrierbetweenthedroplets.Seconditredu__sthewaterssu_____tensionwhichinturnredu__sthewatersabilitytorepulseoil.Thirdtheagentgivesthesu_____softheoildropletsidenticalelectricalcharges;sin__likechargesrepeleachotherthedropletsrepeleachother.油和水为理解乳化过程的发生,我们必须首先认识到这样一条科学原理水和油不能自然混合,它们实实在在互相排斥家制的油醋沙拉调料就是一个好例子当你搅拌沙拉调料时,你不仅使油扩散到醋里,而且使油滴被搅得很小可以悬浮在醋中自此我们改称它为水,因为事实上这种酸性调味品的主要成份就是水一旦你停止了搅动,油滴就会凝聚,大到再也不能悬浮在水中时,它们就向上滑动出来而与水分离了因为油的密度小,所以油会浮在水上如果想得到稳定的乳化,就需要一种乳化剂它可以不让油形成大的油滴自然界中,很多动物体中含有乳化剂,如蛋黄和牛奶乳化剂可以从以下三方面阻止油滴凝聚
一、乳化剂包裹住油滴,在油滴间形成一道物质屏障
二、乳化剂降低水的表面张力,从而降低了水排斥油的能力
三、乳化剂使油滴表面带上了同种电荷,因为同种电荷互相排斥,油滴之间也相互排斥64SaltandMetaboli__Justhowsaltbecamesocrucialtoourmetaboli__isamystery;oneappealingtheorytra__sourdependen__onittothechemistryofthelateCambrianseas.Itwasthereahalfbillionyearsagothattinymetazoanorgani__sfirstevolvedsystemsforsequesteringandcirculatingfluids.Thewateroftheearlyo__ansmightthush__ebecomethechemicalprototypeforthefluidsofallani__llife-themediuminwhich__llularoperationscouldcontinueno__tterhowtheexternalenviro__entchanged.Thisspeculationisbasedonthefactthateventodaythebloodserumsofradicallydivergentspeciesarere__rkablysimilar.Lizardsplatypusessheepandhu__nscouldhardlybemoredifferentinanatomyoreatinghabitsyetthesaltcontentinthefluidsurroundingtheirblood__llsisvirtuallyidentical.Asearly__rinespecics__detheirwaytofreshwaterandeventuallytodrylandsodiumre__inedakeyingre___ntoftheirinteriorifnottheirexteriormilieu.Themostsuc__ssful__m__lianspecieswouldh__ebeenthosethatdevelopedefficienthormonalsystemsfor__intainingtheneededsodiumcon__ntrations.Thehu__nbodyforexampleusesthehormonesreninangiotensinandaldosteronetoretainorreleasetissuefluidsandbloodpla__a.Theresultunderf__orableconditionsisadynamicequilibriuminwhichneitherfluidvolumenorsodiumcon__ntrationfluctuatestoodra__tically.Butifthebodyisdeprivedofsalttheeffectssoonbecomedangerousdespitecompensatorymechani__s.盐与新陈代谢盐为何成为人类新陈代谢的关键是一个谜;一个富有吸引力的理论认为我们对盐的依赖可从寒武纪海洋的化学变化中得到线索五亿年前,就是在那里,微小的后生动物首先进化成与外隔绝的循环液体系统因此,早期海洋里的水可能是所有动物体内液体的化学原型--一个无论外界环境如何改变,其细胞活动仍将继续的环境这个设想是建立这一事实基础上即使是在今天,物种迥异的众多动物血清非常相似蜥蜴、鸭嘴兽、绵羊和人类,在解剖学和饮食习惯上完全不同,但细胞周围的液体中的盐含量却基本上是相等的在海洋生物向淡水区域并最终向陆地__的过程中,盐始终是它们生存环境--如果不是外部环境,其码也是内部环境中的关键成份最高级的哺乳类动物为保持所需的盐浓度而进化出了高效的内分泌系统例如,人体为了保留或释放组织液体和血浆而使用高血压蛋白原酶、血管紧张素、醛固酮等激素这样在有利的环境下,液体与其中盐浓度之间形成的动态平衡,两者均不致出现大起大落但如果身体里丧失了的盐分,尽管有各种的补偿机制,后果将马上极其危险65TheEarlySettlersinNorthAmericaTheNorthAmericanfrontierchangedsomeofthecharacteristicsofthepioneersofthe1750sandintensifiedothers.Theywereasagroupsemiliterateproudandstubbornasdoggedintheirinsisten__ontheirownwayoflifeaspinerootscrackinggranitetogrow.Perhapstheirgreatestresour__wastheircapacitytoendure.Theyoutlastedrecurrentplaguesof__allpoxand__lariaandasteadyprogressionofnaturalaccidents.Theywereincrediblyprolific.SquireBoonesfamilyofeightchildrenwas__allbyfrontierstandards.JamesRobersonaneventualnei___orofBoonesandthefounderofNashvillehadelevenchildren.Twi____rriedJohnSevierthefirstgovernorofTennesseefatheredeighteen;hislongtimeenemyJohnTiptonalsotwi____rriedprodu__dseventeen.Theentireassetsofoneofthesehugefamiliesoftenamountedinthebeginningtolittlemorethananaxeahuntingknifeanaugerarifleahorseortwosomecattleandafewpigsasackofcornseedandanotherofsaltperhapsacrosscutsawandaloom.ThosewhomovedfirstintoanewregionlivedformonthsatatimeonwildmeatIndian__izeandnativefruitsinseason.Yetiftheywerepooratthebeginningtheyconfidentlyexpectedthatsoontheywouldberich.Inawayalmostimpossibletodefinetourbandwellersasli__ofgroundsuitableforfarmingrepresentednotjustdollarsand__ntsbutdignity.TheobsessionbroughtshiploadsofyearnerseveryweektoBostonNewYorkPhiladelphiaBaltimoreCharlesTowneandSavannah.Itsentthemstreamingwestwardintothewildernessaftertheirprede__ssorstoraisestillmorechildrenwhowantedstillmoreland.北美早期殖民者北美的边远地区改变了18世纪50年代拓荒者的一些特点,而强化了他们的另一些特点作为一个整体,他们是半文盲,高傲并且顽固他们坚持自己的生活方式就象松树根在花岗石中爆缝生长也许,他们最大的资源是忍耐能力他们熬过了经常性的天花、疟疾等瘟疫及一系列自然灾难他们出奇地多育依他们的标准,斯夸尔布恩有八个孩子是少的了最后成了布恩的邻居并且是那士维的建造者的詹姆士·罗伯逊有11个孩子曾结过两次婚的约翰·塞维尔--田纳西州的第一位州长,生了18个孩子,他__的仇敌,约翰·提普敦也结过两次婚并有17个孩子最初,在这些庞大的家庭中,全部的财产合起来也不过是一把斧头、一把猎刀和一根钻子,一条步枪,一两匹马,牛和猪,一袋玉米种子和一袋盐,或可能还有一把锯子和一台织布机那些新到一个地区的人们一连数月靠野味、印第安玉米和季节性野果维持生活然而,即使最初很贫穷,他们自信很快就会富起来一块适合耕种的土地不仅仅代表着金钱,更意味着尊严这一点是无法向城市居民解释的这一固执的想法每周都将整船整船的渴望者带往波士顿、纽约、费城、巴尔的摩、查尔斯城和萨瓦那跟随着他们的先行者,这些渴望的人们象潮水一般涌向荒野,去生养更多的子女,而这些子女又将需求更多的土地66PlantsintheDesertsSomecactilikethesaguarogrowtotreesizebuttruetreesneedmoremoisturethanmostdesertenviro__entscansupplysotheyarescar__ondeserts.Closetostreambedscottonwoodscansometimesbefound.Thoughthesestreamsaredrymostoftheyearwaterflowstherelongestandisusually__ailablefairlyclosetothesu_____.Elsewheretreesmustsendtaprootsdeepintothehardbakeddesertsoiltodrawonundergroundwater.Perhapsthemostwidespreadfamilyoftreesontheworldsdesertsistheacaciawhosetaprootsdrilldownasfaras25feet
7.5meters.ThemesquitecommononNorthAmericandesertsinbothtreeandshrubformsdoesnotbegintogrowabovegrounduntilitsrootsystemiscompletelydevelopedensuringtheplantasupplyofmoisture.Therootsofshrubsandtreeshelptoholdthedesertsoilinpla__.Theirstalksandbranchesalsoactasscreenstokeepthewindfromsweepinggreatdriftsofsandalongthesu_____.Theseservi__sarevitalifadesertistosupportlife.Scientistsesti__tethatadesertneedsyearroundplantcoverover20to40per__ntofitssu_____.Ifshrubsaretoofarapart-separatedbyadistan__greaterthanfivetimestheirheight-soilaroundthemislikelytoblowaway.Withouttheshelterofestablishedshrubsnewseedlingswillh__edifficultyingettingastart.Ontheotherhandplantsthataretooclosetogether__ycompeteforundergroundmoisture.Toprotectthemselvesfromthiscompetitionsomeshrubsgiveoffasubstan__thatkillsyoungplantsthatsprouttooclosetothem.Inadditiontoafewvarietiesoftreesandtoughshrubsmostdesertsh__egrassesherbsandotherannualplants.Thesedonotcompeteformoisturewiththelongerlivedgrowth.Theyspringupquicklyafterrainswhenthesu_____ismoist.Thenforabrieftimethedesertcanbeliterallycarpetedwithcolor.Almostasquicklyastheyappearedthese__allplants___away.Buttheyh__edevelopedspecialwaysofensuringthelifeofanothergenerationwhenrainscomeagain.沙漠中的植物一些仙人掌,如撒瓜罗,能长到象树那么高但真正的树却需要比大多数沙漠所能提供的更多的水份,所以树在沙漠里是鲜见的在小溪河床附近,有时能发现三角叶杨尽管一年的大多数时间里这些小溪都是干涸的,那里却是水流得时间最长的地方而且水份相当靠近地表其它地方树木的主根必须深入受炙烤而坚硬的沙漠底部的土壤以吸取地下水在沙漠里分布最广的树或许是刺魏,其主根能深达25英尺合75米牧豆树属植物不论是乔木和灌木,在北美沙漠中常常可见,在它根部系统完全生长发达到能保证提供充足的水分时才长出地面灌木和树的根有助于固定沙漠中的土壤,它们的茎和树枝同时起屏障的作用,防止风从沙漠表面吹起大堆的沙如果沙漠要支持生命,这种作用必不可少科学家估计一年之中植物必须覆盖沙漠表面的20%到40%如果灌木间隔太远--大于它们高度的5倍--周围的土壤就可能被吹走如果没有这些灌木作为保护,新的种子很难生长另一方面,植物相互靠得太近却会引起竞争地下水分为避免竞争,一些灌木会释放一种物质来杀死那些距他们太近发芽的植物除了一些种类的树木和顽强的灌木外,大多数沙漠里还有青草、草本植物和其它年生植物它们并不与__生长的树木竞争水份当雨后地表还潮湿时它们就迅速发芽,然后在一个短时间里,给沙漠铺上绿色地毯这些小植物很快就消失了,几乎就象它们长出来时那样迅速,但它们已发展了特殊方式来保证在下次降雨来时下一代的生命67TheAmericanCivilWarThemilitaryaspectoftheUnitedStatesCivilWarhasalwaysattractedthemostattentionfromscholars.Theroarofgunfirethe__ssedmovementsofuniformedmentheshrillofbuglesandthedra__ofhandtohandcombath__efacinatedstudentsofwa___refora__ntury.Behindthelineshoweverlifewaslessspectacular.Itwasthestoryofbackbreakinglabortoprovidethefightingmenwithfoodandarmsofnervetinglingun__rtaintyaboutthecourseofnationaleventsofheartbreakoversonsorbrothersorhu__andslostinbattle.Ifthemenonthefiringlinewonthevictoriesthemeanstothosevictorieswereforgedonthehomefront.NeverinthenationshistoryhadAmericansworkedharderforvictorythanintheCivilWar.NorthernersandSouthernersalikethrewthemselvesintothetaskofsupplyingtheirrespectivearmies.Bothgover__ents__detremendousde__ndsuponciviliansandingeneralre__ivedwillingcooperations.By1863theNorthernwareconomywasrumblingalonginhighgear.Everythingfromsteamboatstoshovelswasneededandprodu__d.DeniedSoutherncottontextilemillsturnedtowoolforblanketsanduniforms.Hidesbythehundredsofthousandswereturnedintoshoesandharnessandsaddles;ironworks__nufacturedlocomotivesordnan__armorplate.Whereprivateenterpriselaggedthegover__entsetupitsownfactoriesorarsenals.Agricultureboomedwith__chinerydoingthejoboffarmworkersdrawnintothearmy.Inshorteverythingthatanationneededtofightamodernwarwasprodu__dinuncountednumbers.Inevitablytherewereprofiteerswithgoldheadedcanesandflamboyantdiamondstickpinsbutforeverycrookedtycoontherewerethousandsofordinarycitizenslivingonfixedincomeswhodidtheirbesttocopewithrisingpri__sandstill__keacontributiontothewareffort.Thosewhocouldboughtwarbonds;othersknittedsewednursedorlentanyotherassistan__intheirpower.美国内战美国内战中的军事方面一直最吸引学者们的注意轰隆的炮声、军人大规模的阵式,尖锐的军号和白刃战的场面,已吸引了战争研究者们一个世纪然而,在后方,生活却没有这般壮观那里的故事就是为作战的军人提供食物和武装而做劳累至极的工作,对国家事态的焦虑和对在战争中失去丈夫、兄弟和__的撕心裂肺如果说前线的人们获得了胜利,那胜利的手段就要归功于后方的人们在其历史上,美国人从来没有象在内战中那样为夺取胜利而如此努力南方人和北方人一样投入到为各自军队供应物资的任务中双方__对民众都提出巨大的要求,总的来说,得到了极积的合作到了1863年,北方战时经济呈高速运转,从蒸气船到铁锹,一切都需要并且生产出来由于没有了南方产的棉花,纺织工厂纷纷转用毛料生产毯子和军衣几十万件的皮革制成了鞋、挽具和马鞍铁厂生产出机车、大炮、装甲板私营企业不足以承担的方面,__就成立自己的工厂和兵工厂农业迅猛发展,因为农场工人参军后机械代替了手工总之,国家参加现代战争所需的多得数不清的物资都生产出来了不可避免地出现了一些手持镀金手杖,戴着耀眼的钻石别针的投资商但每有一个奸诈的富翁就有成千上万的普通市民他们依靠固定的收入尽他们最大的努力应付着上涨的物价,为战争做着贡献那些有能力的人__战争债券,其他的人编织、缝补衣服,护理伤病人或做其它一切他们力所能及的工作68WomeninColonialNorthAmericaThestatusofwomenincolonialNorthAmericahasbeenwellstu___danddescribedandcanbebrieflysum__rized.Throughoutthecolonialperiodtherewasa__rkedshortageofwomenwhichvariedwiththeregionsandwasalwaysgreatestinthefrontierareas.Thisf__orableratioenhan__dwomensstatusandpositionandallowedthemtopursuedifferentcareers.ThePuritansthereligioussectthatdominatedtheearlybritishcoloniesinNorthAmericaregardedidlenessasasinandbelievedthatlifeinanunderdevelopedcountry__deitabsolutelyne__ssarythateachmemberofthecommunityperformaneconomicfunction.Thusworkforwomen__rriedorsinglewasnotonlyapproveditwasregardedasacivicduty.Puritantowncouncilsexpectedwidowsandunattachedwomentobeselfsupportingandforalongtimeprovidedneedyspinsterswithpar__lsofland.Therewasnosocialsanctionagainst__rriedwomenworking;onthecontrarywiveswereexpectedtohelptheirhu__andsintheirtradeandwonsocialapprovalfordoingextraworkinoroutofthehome.Needychildrengirlsaswellasboyswereindenturedorapprenti__dandwereexpectedtoworkfortheirkeep.Thevast__jorityofwomenworkedwithintheirhomeswheretheirlaborprodu__dmostarticlesneededforthefamily.Theentirecolonialproductionofclothandclothingandpartiallythatofshoeswasinthehandsofwomen.Inadditiontotheseoccupationswomenwerefoundin__nydifferentkindsofemployment.Theywerebutcherssilver__ithsgun__ithsandupholsterers.Theyranmillsplantationstanyardsshipyardsandeverykindofshopt__ernandboardinghouse.Theyweregatekeepersjailkeepers___tonsjournalistsprintersapothecariesmidwivesnursesandteachers.北美殖民时期的妇女北美殖民时期女性的社会地位曾得到过深入研究和描述,并可简短概括整个殖民时期,女性人数明显不足,各地情况不尽相同,在边远地区尤其缺少这种对女性有利的比例提高了她们的社会地位和职位,使她们能追求不同的事业清__是早期英属殖民地的宗教主流它视懒惰为犯罪,认为在不发达农村社区的每一个成员都必须发挥经济作用所以已婚或单身女性工作不仅是许可的,而且被认为是公民的义务清__的镇议会认为寡妇和未婚女性也应该自食其力,而且在相当长一段时期里,向贫困的老而未婚的女子提供土地社会不__已婚妇女工作;相反,要求她们帮助丈夫从事他们的行当在家庭内外做额外劳动的妻子们会得到社会的赞同贫困的儿童,女孩和男孩一样,也要签师徒契约做学徒,想保住这个生计就要工作绝大多数女性在家庭里劳动,生产大部分家用必需品殖民时期全部的布料和衣服以及一部分的鞋都出自女性的双手除了从事这些职业,妇女也从事许多不同类型的职业,如做屠夫、铁匠、军械工和家俱修理工她们经营手工作坊、种植园、制革场、造船厂和各类商店、小旅馆和供膳寄宿处她们当守门人或狱卒,教堂司事、记者、印刷工、药剂师、助产士、护士和教师69TheRevolutioninAmericanHigherEducationToprodu__theuphe__alintheUnitedStatesthatchangedandmodernizedthedo__inofhighereducationfromthemid1860stothemid1880sthreepri__rycausesinteracted.Theemergen__ofahalfdozenleadersineducationprovidedthepersonalfor__thatwasneeded.Moreoveranoutcryforafreshermorepracticalandmoreadvan__dkindofinstructionaroseamongthealumniandfriendsofnearlyalloftheoldcollegesandgrewintoamovementthatoverrodeallconservativeopposition.TheaggressiveYoungYalemovementappearedde__ndingpartialalumnicontrolamoreliberalspiritandabroadercourseofstudy.ThegraduatesofHarvardcollegesimultaneouslyralliedtorelievethecollegespovertyandde__ndnewenterprise.EducationwaspushingtowardhigherstandardsintheEastbythrowingoffchurchleadershipeverywhereandintheWestbyfindingawiderrangeofstu___sandanewsenseofpublicduty.Theoldstyleclassicaleducationre__iveditsmostcrushingblowinthecitadelofHarvardCollegewhereDr.CharlesEliotayoungcaptainofthirtyfivesonofaformertreasurerofHarvardledtheprogressivefor__s.Fiverevolutionaryadvan__swere__deduringthefirstyearsofDr.Eliotsadministration.Theyweretheelevationandamplificationofentran__requirementstheenlargementofthecurriculumandthedevelopmentoftheelectivesystemtherecognitionofgraduatestudyintheliberalartstheraisingofprofessionaltraininginlawmedicineandengineeringtoapostgraduatelevelandthefosteringofgreater__turityinstudentslife.Standardsofadmissionweresharplyadvan__din1872-1873and1876-
1877.Bytheappointmentofadeantotakechargeofstudentaffairsandawisehandlingofdisciplinetheundergraduateswereledtoregardthemselvesmoreasyounggentlemenandlessasyoungani__ls.Onenewcourseofstudyafteranotherwasopenedup-scien__musicthehistoryofthefineartsadvan__dSpanishpoliticaleconomyphysicsclassicalphilologyandinternationallaw.美国高等教育的__从19世纪60年代中期到19世纪80年代中期,改变了美国高等教育并使其现代化的激变有三个互相作用的因素六位教育界__者的出现保证了所需的人力因素除此之外,要求更新、更实用、更高层次的教育呼声在几乎所有老式学院的校友和朋友间升起并发展成压倒所有保守派的一场运动咄咄逼人的青年耶鲁运动出现了,要求校友具有部分控制,更自由的精神和更广的选课范围哈佛学院的毕业生同时团结起来缓解学校的贫困状况并要求新的事业在东部地区的高等学府抛弃了教堂的__,西部地区的学校则扩大了学习范围,树立了一种新的社会责任感,由此教育不断地被推向更高的标准在哈佛学院的__里,旧式的经典教育受到了最毁灭性的打击哈佛以前一个财政主管的__,35岁的年轻领袖查尔斯·艾略特__,__了进步的力量在他管理学院的第一年取得了五个__性的进展那就是提高和加强入学要求,扩充课程和发展选修课,承认大学文科的研究生学习,将法学、医学和工程学的职业训练提高到研究生水平和促进学生生活的成熟入学标准在1872~1873年及1876年~1877年急剧提高由于采用了学生事务院长负责制和明智的处理纪律的手段,大学生把自己更多地看作是年轻的绅士,而不是年轻的动物学校开设了一个又一个的新课程--自然科学、音乐、美术史、高级西班牙语、__经济学、物理、古典语言学和国际法70GarzasArtWorksCarmenLo__sGarzaseloquentetchingslithographsandgouachepaintingsdepictpri__li__gesoftheruralenviro__entandcommunalculturalexperien__ofMexicande__ndedpeopleintheUnitedStates.InanintrospectiveandpersonallanguageshedescribesthecustomstraditionsandwaysoflifeofherTexanMexicanheritage.By1972Lo__sGarzahadevolvedherdistinctivemonitospaintingsofstylizedfiguresinculturallyspecificsocialenviro__ents.Shetransposesi__gesands__nesfromherpastcombiningculturaldocumentationwithinventioninaninterplayoffactandfiction.Throughselectionemphasisandcreationthesemonitosdelineatefa__tsofexperien__expressingdeepertruths.Oraltraditionisa__instayofChicanoculture.Inbothurbanandruralcommunitiesarichandvariedrepertoireofballadstalesandpoeticformsispreservedinmemoryandpassedfromgenerationtogeneration.Lo__sGarzasmonitosfunctionasanoraltraditioninvisualform.Heruniqueartofstory____ingemploysiconographicelementstocreateacon__ntratednarration.Visualepisodeswithinanunfoldingepictaleofculturalregenerationthemonitoskeepalivethecustomsanddailypracti__sthatgivemeaningandcoheren__toChicanoidentity.Theirbasicaimistodelightandinstruct.ForthoseoutsideChicanoculturethepreciseandminutelydetailedmonitosprovideaglimpseintotherichandvibrantlifestyleofthelargestSpanishspeakingculturalgroupwithintheUnitedStatessociety.Althoughherarthasaninno__ntearnestnessandfolkloricaffinityLo__sGarzasexpressionisneithernaivenorinstinctive.Theartistishighlytrainedacademicallybuthaschosentore__inindependentofdominantartistictrendsinordertoworktowardaprivateaestheticresponsetosocialcon__rns.WhileherworkdoesnotpositanovertpoliticalstatementitoriginatesfromadesiretorespondtothecontemporarysituationofMexicanAmericansbyexpressingpositivei__gesoftheirculture.加扎的艺术作品卡门·洛玛斯·加扎富有表现力的蚀刻画、平刻画和树胶水彩画,描绘了美国墨西哥后裔居住的乡村环境和群体的文化经验中的原始形象她用一种反省和个性化的语言,描绘了得克萨斯州墨西哥后裔的风俗、传统和生活方式到1972年为止,洛玛斯·加扎已逐渐完成了风格独特的monitos这是将风格化的人物置身于特定的社会文化环境中的系列画作她从自己的经验中移植出来一些形象和场景,用虚构和现实的交融,实现了文化注释和艺术创造的结合通过挑选、突出和虚构的手段,这些画勾勒了人情事故的各个方面,并表现了更深层的真实口语传统是美国墨西哥文化的主流在城市和农村,人们在记忆中保留了各类民谣、传说和诗歌并世代相传洛玛斯·加扎的monitos,以可视的形象表现了这一口语传统她独一无二的艺术,用肖像法的元素创造了高度凝炼的叙事作为逐渐展开的文化更新史诗中的视觉片断,monitos生动地表现了赋予墨裔美国人有价值及完整的认同感的习俗和日常生活这些画的根本目的是给人娱悦和教育对墨西哥文化以外的人来说,这些画准确而细致地描绘了美国社会中最大的西班牙语文化群的丰富和充满活力的生活方式尽管她的艺术天真、诚挚并与民间艺术有极深的渊源,洛玛斯·加扎的表现手法却绝不幼稚也并不是仅仅出于本能这位艺术家在学术上受过高度训练她选择__于艺术主流之外,目的是对社会的良心做出个性化的美学反应尽管她的作品未提出公开的__宣言,但却是发源于通过描述墨美文化中的正面形象来反映墨美人目前处境的愿望71EvolutionandWheelsInthepastevolutionarybiologistscontemplatingtheabsen__ofwheelsinnatureagreedthattheexplanationwasnotundesirability:wheelswouldbegoodforani__lsjustastheyareforus.Ani__lswerepreventedfromevolvingwheelsthebiologistsreasonedbythefollowingdilem__:living__llsinanani__lsbodyareconnectedtotheheartbybloodvesselsandtothebrainbynerves.Becausearotatingjointisessentialtoawheelawheel__deofliving__llswouldtwistitsarteryveinandnerveconnectionsatthefirstrevolution__kinglivingimpracticable.Howeverthereisaflawintheargumentthattheevolutionofwheeledani__lswasthwartedbytheinsolublejointproblem.Thetheoryfailstoexplainwhyani__lsh__enotevolvedwheelsofdeadtissuewithnoneedforarteriesandnerves.Countlessani__lsincludingusbearexternalstructureswithoutbloodsupplyornerves-forexampleourhairandfingernailsorthescalesclawsandhornsofotherani__ls.Whyh__eratsnotevolvedbonywheelssimilartorollerskatesPawsmightbemoreusefulthanwheelsinsomesituationsbutcatsclawsareretractable:whynotretractablewheelsWethusarriveattheseriousbiologicalparadoxflippantlytermedtheRRRdilem__:naturesfailuretoprodu__ratswithretractablerollerskates.进化与__从前,研究自然界没有__的进化论生物学家都同意不能用无此需要来解释这种现象__对于动物会像对于我们人类一样有好处生物学家们推论,动物没有进化出__是由下述困难所致动物身上的活细胞通过血管与心脏相连,通过神经与大脑相连因为一个旋转的接头对__来说是至关重要的,由活的细胞构成的__在第一次转动时便会扭伤其上的动脉和神经的连结,因而不现实不过,动物未能进化出__是受阻于无法解决接头问题的说法有一个缺陷这种理论无法解释为何动物没有进化出由死组织构成的而无需动脉和神经的__包括人在内的无数动物都有一些没有血液供应和神经的体外构造,例如,我们的头发和指甲,或者鳞片、爪子和其它一些动物的角___老鼠没有进化出类似于滑轮溜冰鞋的骨质的__呢在某些情况下,爪子可能比__更有用,但猫的爪子是可以伸缩的___不能有可以伸缩的__呢这样,我们便得出了一个被戏称为RRR的严肃的生物学悖论大自然未能产生出有可伸缩的滑轮溜冰鞋的老鼠72PopulationGrowthThegrowthofpopulationduringthepastfew__nturiesisnoproofthatpopulationwillcontinuetogrowstraightupwardtowardinfinityanddoom.Onthecontrarydemographichistoryofferseviden__thatpopulationgrowthhasnotbeenatallconstant.AccordingtopaleoecologistEdwardDeeveythepastmillionyearsshowthreemomentouschanges.ThefirstarapidincreaseinpopulationaroundonemillionB.C.followedtheinnovationsoftool__kingandtoolusing.Butwhenthenewpowerfromtheuseoftoolshasbeenexploitedtherateofworldpopulationgrowthfellandbecamealmoststable.Thenextrapidjumpinpopulationstartedperhaps10000yearsagowhen__nkindbegantokeepherdsplowandplanttheearth.On__againwheninitialproductivitygainshadbeenabsorbedtherateofpopulationgrowthabated.ThesetwoepisodessuggestthatthethirdgreatchangethepresentrapidgrowthwhichbeganintheWestbetween250and350yearsago__yalsoslowdownwhenoriftechnologybeginstoyieldfewerinnovations.Ofcoursethecurrentknowledgerevolution__ycontinuewithoutforeseeableend.Eitherway-contrarytopopularbeliefinconstantgeometricgrowth-populationcanbeexpectedinthelongruntoadjusttoproductivity.Andwhenonetakesthisviewpopulationgrowthisseentorepresenteconomicprogressandhu__ntriumphratherthansocialfailure.人口增长以往几个世纪人口的增长并不能证明人口会无限地直线向上增长直到毁灭的地步相反地,人口统计史料证明人口的增长完全不是稳定的古生态学家爱德华·狄维认为,在过去100万年间出现过3次重大的变动第一次在公元前100万年左右,随着在工具的制作和使用上的革新而出现人口迅速增长但当工具的使用所产生的新动力被充分利用以后,世界人口增长率下降并且趋于稳定第二次人口剧增大约始于人类开始蓄畜、垦耕的10,000年前一旦最初的生产力增长被吸收殆尽,人口的增长再次衰落以上两段说明,若技术革新的成果开始减少,从250到350年前就在西方开始出现的并且目前还在继续的人口迅速增长可能也会放慢当然,当前的知识__也许会持续下去而无法预见其末来无论如何,与那种认为人口以几何级数持续增长的观点相反,从长远的观点来说,人口可望受到生产力的调节接受了这一观点,人口的增长就可以被看成是经济进步和人类胜利的标志,而不是社会衰败的标志73Poli__andCommunitiesFewinstitutionsaremoreimportanttoanurbancommunitythanitspoli__yettherearefewsu__ectshistoriansknowsolittleabout.Mostoftheearlyacademicinterestsdevelopedamongpoliticalscientistsandsociologistswhousuallyexaminedtheirowncontemporaryproblemswithonlyanodtowardthepast.Eventhepublicseemedcon__rnedonlyduringcrimew__esperiodsofblatantcorruptionorafteraparticularlygrislyepisode._____regularsandreformersgenerallyviewedtheinstitutionfromapoliticalperspective;newspapersand__gazines-thenineteenth__nturysmedia-emphasizedthevividandspectacular.Yeturbansocietyhasalwaysvestedawideindeedawesomeresponsibilityinitspoli__.Notonlyweretheyto__intainorderpreventcrimeandprotectlifeandpropertybuthistoricallytheywerealsotofightfiressuppressvi__assistinhealthservi__ssuperviseelectionsdirecttrafficinspectbuildingsandlocatetruantsandrunaways.Inadditionitwasassumedthatthepoli__werethespecialguardiansofthecitizenslibertiesandthecommunitystranquillity.Ofcoursetheperfor__n__never__tchedexpectations.Therecordcontainssomesuc__ssbutmostlyfailure;someeffectiveleadershipbutlargelyofficialincompeten__andbetrayal.Thenotionofaprofessionalpoli__for__inAmericaisacreationofthetwentieth__ntury;notuntilourowntimeh__ecitiesbeguntotakethestepsne__ssarytoprodu__moderndepartments.__与社区对城市社区来说,很少有比它的__更为重要的机构了,但少有课题像历史学家们对此了解得那样少早期的学术兴趣是在__科学家和社会学家中发展起来的,他们一般只研究他们自己当代的问题而对过去的问题只是偶尔带过甚至公众似乎也仅仅在犯罪浪潮、明目张胆的贪污或特别的恐怖__发生时才关心政党的忠诚支持者和__家们通常是从__的前途来看待__这个机构;而报纸和__-19世纪的传播媒介-则着重活泼生动和惊人的__可是城市社会总是把广泛得可怕的责任交给__他们不仅维持秩序、防止犯罪、保护生命财产,而且在过去还要救火、__罪恶、协助医疗服务、监督选举、指挥交通、检查建筑物、寻找逃学学生和搜捕逃犯除此以外,__还被认为是公民自由和社会稳定的特别保护者自然,__的表现并不尽如人意他们的记录中有成功者,但多数是失败的;有高效率的__,但多半的人在职务上__和不讲信用专业____的概念在美国还是20世纪的产物;直到我们这个时代,一些城市才开始采取设立现代化部门的必要步骤74FoodandHealthThefoodweeatseemstoh__eprofoundeffectsonourhealth.Althoughscien__has__deenormousstepsin__kingfoodmorefittoeatithasatthesametime__de__nyfoodsunfittoeat.Someresearchhasshownthatperhapseightyper__ntofallhu__nillnessesarerelatedto___tandfortyper__ntofcan__risrelatedtothe___taswellespeciallycan__rofthecolon.Differentculturesaremorepronetocontract__rtainillnessesbecauseofthefoodthatischaracteristicinthesecultures.Thatfoodisrelatedtoillnessisnotanewdiscovery.In1945gover__entresearchersrealizedthatnitratesandnitritescommonlyusedtopreservecolorinmeatsandotherfoodadditivescausedcan__r.Yetthesecarcinogenicadditivesre__ininourfoodanditbecomesmoredifficultallthetimetoknowwhichthingsinthepackaginglabelsofpro__ssedfoodarehelpfulorharmful.Theadditiveswhichweeatarenotallsodirect.Farmersoftengivepenicillintobeefandpoultryandbecauseofthispenicillinhasbeenfoundinthemilkoftreatedcows.Sometimessimilardrugsareadministeredtoani__lsnotformedicinalpurposesbutforfinancialreasons.Thefarmersaresimplytryingtofattentheani__lsinordertoobtainahigherpri__onthe__rket.AlthoughtheFoodandDrugAdministrationFDAhastriedrepeatedlytocontrolthesepro__duresthepracti__scontinue.食品与健康我们所吃的食物似乎对我们的健康有深远的影响尽管科学上已取得许多进展,使食物更适合我们食用,但与此同时它也使许多食物不宜食用了一些研究已经表明,人类大概有80%的疾病与饮食有关,40%的癌症,特别是结肠癌,也与饮食有关不同的文化会使人们更易患某些疾病,这是由这些文化的人们喜好的食物所致食物与疾病有关并不是新发现1945年,__部门的科研工__了解到,被广泛用于肉类以保持肉类色泽的硝酸盐、亚硝酸盐和其他的添加剂可诱发癌症可是这些致癌物质依然存在于我们的食物之中与此同时,要想知道__食品标签上的哪些成分对健康有利,哪些成分对健康不利,变得更加困难了我们吃到的这些添加物并非都是如此直接的农民常给牛和家禽注射青霉素,因而在受过注射的牛所产牛奶里发现青霉素有时让家禽服用这类药物并非是为了治病,而是为了经济上的缘故农民们只是想使家畜长得更肥壮可以上市场上卖到好价钱虽然食物和药品管理局已一再设法控制这种情况的发生,但是这种行为仍在继续75__RS__rsAccordingtothebesteviden__gatheredbyspa__probesandastronomers__rsisaninhospitableplanetmoresimilartoEarthsMoonthantoEarthitself-adrystarkseeminglylifelessworld.__rsairpressureisequaltoEarthsatanaltitudeof100000feet.Theairthereis95%carbondioxide.__rshasnoozonelayertoscreenouttheSunslethalradiation.Daytimetemperatures__yreachabovefreezingbutbecausetheplanetisblanketedbythemerewispofanatmospheretheheatradiatesbackintospa__.Evenattheequatorthetemperaturedropsto50℃60atnight.Todaythereisnoliquidwateralthoughvalleysandchannelsonthesu_____showeviden__ofh__ingbeencarvedbyrunningwater.Thepolari__capsare__deoffrozenwaterandcarbondioxideandwater__ybefrozeninthegroundasper__frost.Despitethesedifficultconditions__rtainscientistsbelievethatthereisapossibilityoftransforming__rsintoamoreEarthlikeplanet.Nuclearreactorsmightbeusedtomeltfrozengasesandeventuallybuilduptheatmosphere.Thisinturncouldcreateagreenhouseeffectthatwouldstopheatfromradiatingbackintospa__.Liquidwatercouldbethawedtoformapolaro__an.On__enoughi__hasmeltedsuitableplantscouldbeintrodu__dtobuildupthelevelofoxygenintheatmospheresothatintimetheplanetwouldsupportani__llifefromEarthandevenper__nenthu__ncolonies.Thiswason__thoughttobesofarinthefutureastobeirrelevantsaidChristopherMcKayaresearchscientistattheNationalAeronauticsandSpa__Administration.Butnowitsstartingtolookpractical.Wecouldbeginworkinfourorfivedecades.Theideaofterraforming__rsasenthusiastscallithasitsrootsinscien__fiction.ButasresearchersdevelopamoreprofoundunderstandingofhowEarthsecologysupportslifetheyh__ebeguntoseehowit__ybepossibletocreatesimilarconditionson__rs.Dontplanonhomesteadingon__rsanytimesoonthough.Thepro__sscouldtakehundredsoreventhousandsofyearstocompleteandthecostwouldbestaggering.火星据宇宙探测器和天文学家收集的有力证据,火星是一个人类不能居住的星球它不像地球,而更像月球--一个干涸、荒芜,看上去没有任何生命的世界火星的气压相当于地球上十万英尺高空处的气压火星大气的构成中有95%是二氧化碳,而且,火星上没有能屏蔽太阳致命射线的臭氧层白天,那里的温度可以达到零上,但因为包裹火星的大气层极为稀薄,热量又会辐射回宇宙中就算是在火星赤道,夜里的温度也在50℃尽管火星上的山谷沟渠说明它曾经被流水蚀刻过,但如今那里已没有液态水了极地冰帽是由固态水和二氧化碳组成的,水也有可能存在于永久冻土之中尽管困难重重,某些科学家依然认为有可能把火星改造成类似地球的星球核反应可以用来融化冰冻的气体最终形成火星大气层由此就可以产生温室效应,阻止热量散射回宇宙中液化的水可以融化成极地海洋足够量的冰融化后,可将地球上的植物移植上去植物又可以向大气层提供氧气久而久之火星就可以维持从地球过去的动物生命甚至成为人类的永久居留地这一切在过去看起来遥远得近乎无稽,国家__局的一位研究人员,克里斯托弗·麦克凯说,但是现在已经开始展现出可能性四五十年后,我们就可以着手于这项工作这种支持者们称为移居火星的想法最早出现在科幻小说中但随着研究者对地球上生态如何支持生命的理解越来越深入,在火星上创造类似地球环境也显得越来越现实但千万别计划很快在火星上建造家园这个历程需要几百乃至上千年,而且耗费将是惊人的76HydrogenandIndustriesHydrogenthelightestand______stoftheelementshasseveralpropertiesthat__keitvaluablefor__nyindustries.Itreleasesmoreheatperunitofweightthananyotherfuel.Inrocketenginestonsofhydrogenandoxygenareburnedandhydrogenisusedwithoxygenforweldingtorchesthatprodu__temperaturesashighas4000degreesFandcanbeusedincuttingsteel.Fuel__llstogenerateelectricityoperateonhydrogenandoxygen.Hydrogenalsoservestopreventmetalsfromtarnishingduringheattreatmentsbyremovingtheoxygenfromthem.Althoughitwouldbedifficulttoremovetheoxygenbyitselfhydrogenreadilycombineswithoxygentoformwaterwhichcanbeheatedtosteamandeasilyremoved.Hydrogenisalsousefulinthefoodindustryforapro__ssknowashydrogenation.Productssuchas__rgarineandcookingoilsarechangedfromliquidstosemisolidsbyaddinghydrogentotheirmolecules.Soap__nufacturersalsousehydrogenforthispurpose.Hydrogenisalsooneofthecoolestrefrigerants.Itdoesnotbecomealiquiduntilitreachestemperaturesof-425degreesF.Purehydrogengasisusedinlargeelectricgeneratorstocoolthecoils.Inadditioninthechemicalindustryhydrogenisusedtoprodu__ammoniagasolinemethylalcoholand__nyotherimportantproducts.氢与工业氢作为最轻和最简单的无素,有几种特性对工业非常有用作为燃料,它每单位重量释放热量最多,在火箭的引擎中,成吨的氢和氧被燃烧掉氢和氧合在一起用于焊接,能够产生高达华氏四千度的高温而可以切割钢铁发电的燃料房就是使用氢和氧氢也可以用来在金属热处理中通过从中除去氧的方法来防锈虽然单独除去氧本身是困难的,氢和氧很容易结合成水,而水是可以加热蒸发除去的氢在食品工业中对于所谓的氢化过程也很有用人造黄油和食用油的分子中加上氢,就由液态变成半固态肥皂制造商也为此使用氢氢是温度最低的冷冻剂它要到华氏-425度才会液化纯氢被用于大型发电机线圈的冷却除此之外,在化学工业中,氢被用来制造氨、汽油、甲醇以及其它许多重要产品77TheHistoryofChemistryChemistrydidnotemergeasascien__untilafterthescientificrevolutionintheseventeenth__nturyandthenonlyratherslowlyandlaboriously.Butchemicalknowdedgeisasoldashistorybeingalmostentirelycon__rnedwiththepracticalartsofliving.Cookingisessentiallyachemicalpro__ss;soisthemeltingofmetalsandtheadministrationofdrugsandpoisons.Thisbasicchemicalknowledgewhichwasappliedinmostcasesasaruleofthumbwasneverthelessdependentonpreviousexperiment.Italsoservedtostimulateafundamentalcuriosityaboutthepro__ssesthemselves.Newinfor__tionwasalwaysbeinggainedasartisansimprovedtechniquestogainbetterresults.Thedevelopmentofascientificapproachtochemistrywashoweverhamperedbyseveralfactors.Themostseriousproblemwasthevastrangeof__terial__ailableandtheconsequentdifficultyoforganizingitintosomesystem.Inadditionthereweresocialandin____ectualdifficuliteschemistryisnothingifnotpractical;thosewhopracti__itmustusetheirhandstheymusth__ea__rtainpracticalflair.Yetin__nyancientcivilizationspracticaltaskswerepri__rilytheprovin__ofasl__epopulation.Thethinkerorphilosopherstoodapartfromthismundaneworldwherethepracticalartsappearedtolackanyin____ectualcontentorinterest.Thefinalproblemforearlychemicalscien__wastheelementofsecrecy.Expertsinspecifictradeshaddevelopedtheirowntechniquesandguardedtheirknowledgetopreventothersfromstealingtheirlivelihood.Anotherfactorthatcontributedtosecrecywastheesotericnatureoftheknowledgeofaalchemistswhoweretryingtotransformbasemetalsintogoldorwerecon__rnedwiththehuntfortheelixirthatwouldbestowtheblessingofeternallife.Inonesensethesecondofthesewasthemoreseriousimpedimentbecausetherecordsofthechemicalpro__ssesthatearlyalchemistshaddiscoveredwereoftenwrittendowninsymboliclanguagein____igibletoveryfeworinsymbolsthatwerepurposelyobscure.化学的历史化学在17世纪的科技__后才成为一门科学,其发展是缓慢而艰难的但化学知识却象人类历史一样古老,与人们实际生活密切相关做饭基本上是一个化学过程同样,金属熔炼、使用药品或毒剂也是如此人们在大多数情况下只是粗糙地运用这些基本化学知识,但这些基本知识的确是来自于前人的实验它们同时也激发了人们对化学本身的兴趣匠人们利用新技术来改良工艺,就增加了对化学的了解但是,化学科学方法的发展却有许多阻碍的因素其中最严重的问题就是要把浩如烟海的物质归纳为若干系统确实很困难此外,还有社会和知识的原因离开实际用途,化学就毫无价值;研究化学的人必须亲自动手,这就要求他们要有很强的动手能力但在许多古代文明中,动手的活都是奴隶的行当思想家与哲学家与此劳碌决不沾边,因为在他们看来,实际操作技能低智而乏味最后,还有一个原因妨碍早期化学的发展,那就是保密某个行家一旦发现了新技术,就竭力保密以防被人偷了饭碗另一个原因加剧了知识封锁这是因为炼金术士的知识的神秘性这些术士们要么想他便宜的金属变成黄金,要么期望找到一种长生不老药从某种意义上说,这第二个因素带来了更严重的阻碍,因为早期术士们的研究成果记载于鲜为人知的或故意让人不懂的符号中78TheMicroscopicTechniqueEachadvan__inmicroscopictechniquehasprovidedscientistswithnewperspectivesonthefunctionoflivingorgani__sandthenatureof__tteritself.Theinventionofthevisiblelightmicroscopelateinthesixteenth__nturyintrodu__dapreviouslyunknownrealmofsingle__lledplantsandani__ls.Inthetwentieth__nturyelectronmicroscopesh__eprovideddirectviewsofvirusesandminusculesu_____structures.Nowanothertypeofmicroscopeonethatutilizesxraysratherthanlightorelectronsoffersadifferentwayofexaminingtinydetails;itshouldextendhu__nper__ptionstillfartherintothenaturalworld.Thedreamofbuildinganxraymicroscopedatestoback1__5;itsdevelopmenthoweverwasvirtuallyhaltedinthe1940sbecausethedevelopmentoftheelectronmicroscopewasprogressingrapidly.Duringthe1940selectronmicroscopesroutinelyachievedresolutionbetterthanthatpossiblewithavisiblelightmicroscopewhiletheperfor__n__ofxraymicroscopesresistedimprovement.Inre__ntyearshoweverinterestinxraymicroscopeshasrevivedlargelybecauseofadvan__ssuchasthedevelopmentofnewsour__sofxrayillumination.Asaresultthebrightness__ailabletodayismillionsoftimesthatofxraytubeswhichformostofthe__nturyweretheonly__ailablesour__sofsoftxrays.Thenewxraymicroscopesconsiderablyimproveontheresolutionprovidedbyopticalmicroscopes.Theycanalsobeusedto__pthedistributionof__rtainchemicalelements.Somecanformpicturesinextremelyshorttimes;othersholdthepromiseofspecialcapabilitiessuchasthreedimensionali__ging.Unlikeconventionalelectronmicroscopexraymicroscopeenablesspecimenstobekeptinairandinwaterwhichmeansthatbiologicalsamplescanbestu___dunderconditionssimilartotheirnaturalstate.Theilluminationusedsocalledsoftxraysinthew__elengthrangeoftwentytofortyangstromsanangstromisonetenbillionthofameterisalsosufficientlypenetratingtoi__geintactbiological__llsin__nycases.Becauseofthew__elengthofthexraysusedsoftxraymicroscopeswillnever__tchthehighestresolutionpossiblewithelectronmicroscopes.Rathertheirspecialpropertieswill__kepossibleinvestigationsthatwillcomplementthoseperformedwithlightandelectronbasedinstruments.显微技术显微镜技术的每一个进步都给科学家提供了看待生物体的功能和其性质的新观察方式16世纪晚期可视光显微镜的发明引入了一个以前一无所知的单细胞植物和动物的领域20世纪电子显微镜提供了对病毒和极微物体的表面结构的直接观察现在一种新的显微镜,利用X光而不是自然可见光或电子,为观察微小细节提供了不同的观察方式,它将扩展人类对自然世界进行的更深入的认识研制X光显微镜的梦想可追溯到1875年;但它的发展却在20世纪40年代实际上停止了,因为电子显微镜的发展进行很快在40年代,电子显微镜毫无例外地比可见光显微镜获得了更好的分辨能力然而X光显微镜的表现却没有改进但近年来,对它的兴趣又复活了,这很大程度是因为例如X射线在新光源上的发展的结果结果,今天可得到的亮度是大半个世纪以来唯一可得到的X光源-X光管的几百万倍新的X光显微镜相当大地提高了电子学显微镜提供的分辨能力它们也可用来给某些化学元素绘制分布图某些X光显微镜可以在极短的时间里成像另一些可望具备三维成像的特殊功能与传统的电子显微镜成像术不同,X光显微镜成像术可使分析样本保留在空气或水中这就意味着生物样品可以在与它们自然环境相近的条件下被观察研究其使用的照明度,即所谓的软性X射线,其波长在20到40埃之间1米的100亿分之一为1埃在许多情况下也能够穿透完整无缺的生物细胞并成像由于使用的X射线的波长使软性X射线显微镜永远比不上电子显微镜可能具有的最高分辨力不过他们特殊的功能将可能补充那些用自然光和电子仪器所进行的观察79TheSatiricLiteraturePerhapsthemoststrikingqualityofsatiricliteratureisitsfreshnessitsoriginalityofperspective.Satirerarelyoffersoriginalideas.Insteaditpresentsthefamiliarinanewform.Satiristsdonotoffertheworldnewphilosophies.Whattheydoistolookatfamiliarconditionsfromaperspectivethat__kestheseconditionsseemfoolishharmfuloraffected.Satirejarsusoutofcompla__n__intoapleasantlyshockedrealizationthat__nyofthevaluesweunquestioninglyac__ptarefalse.DonQuixotederidesthestupidityofknightsBr__eNewWorldridiculesthepretensionsofscien__;AModestProposaldra__tizesstarvationbyadvocatingcannibali__.Noneoftheseideasisoriginal.Chivalrywassuspectbefore__rvanteshu__nistso__ectedtotheclaimsofpurescien__beforeAldousHuxleyandpeoplewereawareoffaminebeforeSwift.Itwasnottheoriginalityoftheideathat__dethesesatirespopular.Itwasthe__nnerofexpressionthesatiricmethodthat__detheminterestingandentertaining.Satiresarereadbecausetheyareaestheticallysatisfyingworksofartnotbecausetheyaremorallywholesomeorethicallyinstructive.Theyarestimulatingandrefreshingbecausewithcommonsensebrisknesstheybrushawayillusionsandsecondhandopinions.Withspontaneousirreveren__satirerearrangesperspectivesscramblesfamiliaro__ectsintoincongruousjuxtapositionandspeaksinapersonalidiominsteadofabstractplatitude.Satireexistsbecausethereisneedforit.Ithaslivedbecausereadersappreciatearefreshingstimulusanirreverentreminderthattheyliveinaworldofplatitudinousthinkingcheapmoralizingandfoolishphilosophy.Satireservestoprodpeopleintoanawarenessoftruththoughrarelytoanyactiononbehalfoftruth.Satiretendstoremindpeoplethatmuchofwhattheyseehearandreadinpopularmediaissanctimonioussentimentalandonlypartiallytrue.Liferesemblesinonlyaslightdegreethepopulari__geofit.Sol___rsrarelyholdtheidealsthatmoviesattributetothemnordoordinarycitizensdevotetheirlivestounselfishservi__ofhu__nity.In____igentpeopleknowthesethingsbuttendtoforgetthemwhentheydonothearthemexpressed.讽刺文学或许讽刺文学最显著的特点是其视角的新颖性和独特性讽刺作品很少有创造性的思想相反,它用一种新的形式把人们熟悉的东西呈现出来讽刺作家没有为世界贡献新的哲学他们所做的就是采取这样一种立场来看待熟悉的环境,使得它们看上去愚蠢、有害或者造作讽刺作品使我们排除了自满情绪,并愉快地惊叹道许多我们毫无疑问地接受的价值观是错误的《堂吉诃德》使骑士看起来愚蠢可笑;《奇妙的新世界》嘲弄了科学的自命不凡;《温和的建议》戏剧性地提倡同类相食来消灭饥饿所有这些观点都不是创造性的在塞万提斯以前骑士制度就受到了怀疑,在阿尔道斯·赫胥黎以前的人文主义者就__纯科学的主张,而且在斯威夫特以前就认识了饥荒并不是独创性的思考使这些讽刺作品变得流行,而是表达的方式、讽刺的方法手段使它们变得有趣和引人入胜人们读讽刺作品是因为在美感上它们是令人满意的艺术作品,而不是因为道德的__和伦理的说教它们有启发性、使人耳目一新是因为它们用简明的常识洗刷去了幻觉和旧的观点讽刺作品用自然的嘲讽态度重新设置了观点,将熟悉的事物自相矛盾地置在一起讽刺文学用自己的语言,而不是采用抽象的陈词滥调来表达讽刺作品的存在是由于有需求它的存在是因为读者欣赏使人耳目一新的__,毫不客气地提醒他们活在一个思相陈腐、道德低廉、哲学荒谬的世界里讽刺作品有助于促进人们认识__,虽然很少促动人们为真理而行动它有助于提醒人们日常媒介中所见所闻所谈的许多东西是假装神圣、感情用事或半真半假生活只在很少程度上与它流行的映像相象,战士很少有电影赋予他们的__,一般的公民也很少奉献他们的生命为人类无私的服务明智的人们了解这些事理,但当他们没有听到这些事理,就倾向于把它们忘掉80TheAlaskaPipelineTheAlaskapipelinestartsatthefrozenedgeoftheArcticocean.Itstretchessouthwardacrossthelargestandnorther__oststateintheUnitedStatesendingataremotei__freeseaportvillagenearly800milesfromwhereitbegins.Itis__ssiveinsizeandextremelycomplicatedtooperate.Thesteelpipecrosseswindsweptplainsandendlessmilesofdelicatetundrathattopsthefrozenground.Itwe__esthroughcrookedcanyonsclimbssheermountainsplungesoverrockycrags__kesitswaythroughthickforestsandpassesoverorunderhundredsofriversandstreams.Thepipeis4feetindiameterandupto2millionbarrelsor84milliongallonsofcrudeoilcanbepumpedthroughitdaily.RestingonHshapedsteelrackscalledbentslongsectionsofthepipelinefollowazigzagcoursehighabovethefrozenearth.Otherlongsectionsdropoutofsightbeneathspongyorrockygroundandreturntothesu_____lateron.Thepatternofthepipelinesupanddownrouteisdeterminedbytheoftenharshde__ndsoftheArcticandsubarcticcli__tethetortuouslayofthelandandthevariedcompositionsofsoilrockorper__frostper__nentlyfrozenground.Alittlemorethanhalfofthepipelineiselevatedabovetheground.There__inderisburiedanywherefrom3to12feetdependinglargelyuponthetypeofterrainandthepropertiesofthesoil.Oneofthelargestintheworldthepipelinecostapproxi__tely$8billionandisbyfarthebiggestandmostexpensiveconstructionprojecteverundertakenbyprivateindustry.Infactnosinglebusinesscouldraisethatmuchmoneyso8__joroilcompaniesformedaconsortiuminordertosharethecosts.Eachcompanycontrolledoilrightstoparticularsharesoflandintheoilfieldsandpaidintothepipelineconstructionfundaccordingtothesizeofitsholdings.Todaydespiteenormousproblemsofcli__tesupplyshortagesequipmentbreakdownslabordisagreementstreacherousterraina__rtainamountofmi__anagementandeventhefttheAlaskapipelinehasbeencompletedandisoperating.__斯加输油管__斯加输油管道以北冰洋的冻冰边缘为起点,向南延伸穿过美国的最北又是最大的州,在离起点800英里以外的一个偏僻的不冻海港中止它跨幅巨大,而且运作极端复杂这个钢质管道穿过强风不断的草原和无边无尽的覆盖于冻土之上的苔原它盘垣于弯曲的峡谷之间,攀上陡峭的山峰,从岩石遍布的峭壁俯冲下来,穿越浓密的森林,从上或从下经过成百上千条的河流与溪水管道的直径有四英尺,每天能运送高达200百万桶合8400万加仑的原油枕在H型的铁架上,管道长长的一部分在冰冻地面的上空走着之字形其它部分消失在松软或坚硬的地面下然后又回到地面上管道这种或上或下的路线决定于严酷的极带和副极带气候、复杂的地形和构造各异的土壤、岩石、永久冻土一大半管道悬在地面上空,其余部分则埋入3至12英尺的地下深浅大部分由地形状况和土壤特征而定作为世上最大的管道之一,它花费了将近80亿美元,至今仍是私有产业进行的最浩大最昂贵的建筑工程实际上,单个公司不可能拿出这么多的资金为了分担成本,八大石油公司组成了一个大财团每个公司都控制着油田中一定土地上的开采权,并由股份的比例把资金投入到管道建设中尽管有气候严寒、供应不足、设备损坏、劳工纠纷、地形复杂等巨大困难,并有一些管理上的不善甚至被盗现象,__斯加管道现已峻工并正在运行以上就是这80篇英文短文故事的所有内容了,都是中英双语字幕模式的,适合儿童英语、少儿英语、幼儿英语学习者,既可以作英语学习内容,也可以作为课外拓展阅读资料,为孩子学英语增加乐趣和热情,还可以增进亲子互动交流,有心的爸妈收好哦~关于瑞思学科英语瑞思学科英语成立于2007年,率先从事学科英语教育的行业领航者,专业的少儿英语培训专家,至今十余载,依托美国霍顿·米夫林·哈考特教育集团的全球__教育资源,其“浸入式学科英语”课程体系涵盖3~6岁幼儿英语、7~12岁儿童英语、13~18岁青少儿英语,并将项目管理能力、演讲演示能力和团队合作能力等未来___必备的综合素质贯彻始终瑞思学员使用的多媒体互动课程,在美国超过50%以上的学生,在全球120多个国家也在同步使用每天,在全国80多个城市250多家校区,近十万名学员同步使用瑞思课程;每年有数十万家庭选择让孩子在瑞思学习英语,其中又有90%以上的家庭选择持续续费,让孩子一直在瑞思学习,直至进入美国名校。