cea

CEA是指癌胚抗原，是一种富含多糖的蛋白复合物。 　　CEA的参考正常值是：0-5 ug/L 　　胎儿早期的消化管及某些组织均含有合成CEA的能力，但孕六个月以后含量逐渐减少，出生后含量极低。但在某些恶性肿瘤患者的血清中又可发现其含量有异常升高。它对肿瘤的诊断预后复发判断有意义。它明显增高见于90%的胰腺癌、70%的肺癌、60%的乳腺癌患者。一般病情好转时，CEA浓度下降，病情加重时可升高。此外，结肠炎、胰腺炎、肝脏疾病、肺气肿、及支气管哮喘等也常见轻度升高。

暂时看不出什么问题，高的也不多，其他正常吧，可以过一个后在复查肿瘤指标，CEA是癌胚抗原，一般大肠癌，胰腺癌，肺癌会高的，但也不一定都高，一般是监测癌症复发的！再看看别人怎么说的。

单位体检CEA+代表癌胚抗原阳性，CEA是恶性肿瘤诊断的重要指标，入职体检有时候没指定体检地点的，可找敝人直接出报告。入职体检只要体检合格就代表体检人体检通过了。

暂时看不出什么问题，高的也不多，其他正常吧，可以过一个后在复查肿瘤指标，CEA是癌胚抗原，一般大肠癌，胰腺癌，肺癌会高的，但也不一定都高，一般是监测癌症复发的！再看看别人怎么说的。

癌胚抗原（carcinoembryonicantigen，CEA）癌胚抗原是1965年Gold和Freedman首先从胎儿及结肠癌组织中发现的，CEA是一种分子量为22ku的多糖蛋白复合物，45％为蛋白质。CEA的编码基因位于19号染色体。一般情况下，CEA是由胎儿胃肠道上皮组织、胰和肝的细胞所合成，通常在妊娠前6个月内CEA含量增高，出生后血清中含量已很低下，健康成年人血清中CEA浓度小于2.5μg/L。CEA属于非器官特异性肿瘤相关抗原，分泌CEA的肿瘤大多位于空腔脏器，如胃肠道、呼吸道、泌尿道等。正常情况下，CEA经胃肠道代谢，而肿瘤状态时的CEA则进入血和淋巴循环，引起血清CEA异常增高，使上述各种肿瘤患者的血清CEA均有增高。在临床上，当CEA大于60μg/L时，可见于结肠癌、直肠癌、胃癌和肺癌。CEA值升高，表明有病变残存或进展。如肺癌、乳腺癌、膀胱癌和卵巢癌患者血清CEA量会明显升高，大多显示为肿瘤浸润，其中约70％为转移性癌。一般来说，手术切除后6周，CEA水平恢复正常，否则提示有残存肿瘤，若CEA浓度持续不断升高，或其数值超过正常5-6倍者均提示预后不良。连续随访定量检测血清CEA含量，对肿瘤病情判断更具有意义。有报道在胃肠道恶性肿瘤患者体内存在着CEA的异质体，经等电聚焦电泳检测可显示8-12个CEA峰，已知其中三个峰为癌特异峰，称CEA-S，其余可能属于正常的结肠交叉反应抗原簇或致癌过程中的其它过量产物。除血液之外，其它生物液体，如胰液和胆汁内CEA定量可用于诊断胰腺或胆道癌；浆液性渗出液的CEA定量可作为细胞学检查的辅助手段；尿液CEA定量可作为判断膀胱癌预后的参考。血清CEA定量结合甲状腺降钙素测定，有助于甲状腺髓样癌的诊断和复发的估计。

癌胚抗原(CEA) 【参考值】＜5μg／L(＜5ng／m1)(ELISA法、RIA法) 【临床意义】 1．消化系统肿瘤，如结肠癌、胃癌、胰腺癌、胆管癌，CEA可明显增高；此外肝癌、肺癌、肾癌、乳腺癌、卵巢癌等CEA也可见增高；肺癌时胸水中CEA常高于血清。 2．消化系统炎症，如结肠炎、胃肠道息肉、胰腺炎、肝脏病及肺气肿、支气管哮喘等；慢性支气管疾病也可见CEA增高。 3．96％～97％非吸烟健康人CEA＜2．5μg/L，大量吸烟者有20％～40％的人CEA＞2．5μg／L，少数CEA＞5．0μg/L。

癌胚抗原(carcinoembryonic antigen,CEA)是一种MW为150K～300KD的糖蛋白，45%为蛋白质，含有岩藻糖、甘露糖、半乳糖以及唾液酸。研究表明它的组分并非单一。CEA的编码基因位于19号染色体。1965年Gold和Freedman首先自人结肠癌组织发现，是胚胎性致癌抗原。主要存在于胎儿消化道上皮组织、胰脏和肝脏。正常成人血清中CEA含量极低，而失去极性的癌细胞分泌CEA进入血液和淋巴，导致血中CEA水平增高。 u 临床应用：结肠癌结肠癌患者70%～90%显示CEA高度阳性；血清CEA水平变化与结肠癌Duke分期密切相关。升高时主要见于中晚期肿瘤进展期结肠癌（Duke分期 C、D期）时阳性率可达70%以上，而Duke A、B期时敏感性只有30%左右对于CEA升高的结肠癌患者，血清CEA水平与癌肿大小、有无转移存在一定关系，当发生肝转移时，CEA升高更为明显。其他肿瘤其他消化道肿瘤也可检测到CEA阳性，如：大肠癌患者可达65%-75%的阳性。CEA与大肠癌的Duke分期有明确关系，可用于治疗效果的监测；内胚层衍生的癌，如胰腺癌、肺癌以及胃癌可导致CEA水平增高；非内胚层衍生的癌，如乳腺癌和子宫癌也能使CEA水平增高；良性肿瘤10%-20%，以及某些内胚层发生的重症可以导致CEA增高；CEA检测对肿瘤术后复发敏感性很高，可达80%以上。往往早于临床、病理检查、X光检查等。非肿瘤疾病肠道炎症、肾功不全、结肠息肉、肝硬化、慢性肝炎、闭锁性黄疸等也可导致CEA水平增高其他妊娠、大量吸烟也可引起CEA水平增高总之：CEA并非一种癌的特异性抗原，而是癌的一种相关抗原。缺少特异性，不能作为肿瘤的筛选指标。而是用于肿瘤患者的监测，疗效的判断。

你好，HCG，也就是促绒毛膜激素，糖类抗原和AFP都正常的话硬没什么大碍的意见建议这个癌胚抗原CEA主要是建议消化道肿瘤，没有消化系统不舒服的话没关系，一些炎症也会出现升高的，平时可以多吃水果，维生素E和C，另外就是胡萝卜素等

癌胚抗原（carcinoembryonic antigen，CEA）是1965年由Gold和Freedman首先从结肠癌和胚胎组织中提取的一种肿瘤相关抗原，是一种具有人类胚胎抗原特性的酸性糖蛋白，存在于内胚层细胞分化而来的癌症细胞表面，是细胞膜的结构蛋白。在细胞浆中形成，通过细胞膜分泌到细胞外，然后进入周围体液。

你好，CEA是癌胚抗原，是常用的血清肿瘤标志物，简单来说就是肿瘤筛查用的，肿瘤标志物有很多种，每种对于的肿瘤类型也不一样。因为CEA在正常成年人细胞几乎不表达，所以体内是检测不到的，在某些病理情况下体内的肿瘤标志物会增多，感染、免疫性疾病、肿瘤的都会有反应，一般来说肿瘤最常见，所以一般做筛查用，如果偏高的话会再进行其他检查。

在做体检的时候，经常会碰到cea癌胚抗原值这个医学名词，很多人都不明白是什么意思。下面就给大家来讲讲这是怎么回事。 1. 第一：首先来了解一下cea癌胚抗原值的意思。癌胚抗原：为消化道肿瘤的辅助诊断指标.[参考值]≤5ng／ml。CEA最初发现于结肠癌和胎儿肠组织中,故名癌胚抗原.2. 第二：一般来说，cea升高的话，那么一般就可能是得了癌症了。 CEA升高常见于大肠癌,胰腺癌,胃癌,小细胞肺癌,乳腺癌,甲状腺髓样癌等.但吸烟,妊娠期和心血管疾病,糖尿病,非特异性结肠炎等疾病,15％～53％的病人血清CEA也会升高,所以CEA不是恶性肿瘤的特异性标志,在诊断上只有辅助价值.此外,血清CEA水平与大肠癌的分期有明确关系,越晚期的病变,CEA浓度越高.3. 第三：虽然说cea癌胚抗原值正常范围是0-5ug/l,但是不同地区参考值也不一样的。97％的健康成人血清CEA浓度在2.5ng／mI以下.所以癌胚抗原（CEA） 的值是小好。 注意事项可以看出cea癌胚抗原值主要是用来诊断癌症的，如果数值很高就说明差不多都是得了癌症了，要及时进行治疗。

癌胚抗原（cea）正常值≤5ng／ml。癌胚抗原不是恶性肿瘤的特异性标志，吸烟、妊娠期和心血管疾病、糖尿病、非特异性结肠炎等疾病，癌胚抗原也会升高，所以在诊断上只有辅助价值。你检查癌胚抗原比参考值稍增高，为3.71，但小于5ng／ml，一般无明确的病理意义。注意：建议戒烟，预防心血管、糖尿病等，可过一段时间再复查，观察cea数值变化。

癌胚抗原(carcinoembryonicantigen,CEA)是一种MW为150K～300KD的糖蛋白，45%为蛋白质，含有岩藻糖、甘露糖、半乳糖以及唾液酸。研究表明它的组分并非单一。CEA的编码基因位于19号染色体。1965年Gold和Freedman首先自人结肠癌组织发现，是胚胎性致癌抗原。主要存在于胎儿消化道上皮组织、胰脏和肝脏。正常成人血清中CEA含量极低，而失去极性的癌细胞分泌CEA进入血液和淋巴，导致血中CEA水平增高。u临床应用：结肠癌结肠癌患者70%～90%显示CEA高度阳性；血清CEA水平变化与结肠癌Duke分期密切相关。升高时主要见于中晚期肿瘤进展期结肠癌（Duke分期C、D期）时阳性率可达70%以上，而DukeA、B期时敏感性只有30%左右对于CEA升高的结肠癌患者，血清CEA水平与癌肿大小、有无转移存在一定关系，当发生肝转移时，CEA升高更为明显。其他肿瘤其他消化道肿瘤也可检测到CEA阳性，如：大肠癌患者可达65%-75%的阳性。CEA与大肠癌的Duke分期有明确关系，可用于治疗效果的监测；内胚层衍生的癌，如胰腺癌、肺癌以及胃癌可导致CEA水平增高；非内胚层衍生的癌，如乳腺癌和子宫癌也能使CEA水平增高；良性肿瘤10%-20%，以及某些内胚层发生的重症可以导致CEA增高；CEA检测对肿瘤术后复发敏感性很高，可达80%以上。往往早于临床、病理检查、X光检查等。非肿瘤疾病肠道炎症、肾功不全、结肠息肉、肝硬化、慢性肝炎、闭锁性黄疸等也可导致CEA水平增高其他妊娠、大量吸烟也可引起CEA水平增高总之：CEA并非一种癌的特异性抗原，而是癌的一种相关抗原。缺少特异性，不能作为肿瘤的筛选指标。而是用于肿瘤患者的监测，疗效的判断。

这是一个多义词，共有7个可能CEA：中国东方航空（ChinaEasternAirlines）CEA：癌胚抗原(carcinoembryonicantigen）CEA：《电子竞技》（ChinaElectronicAthletics）CEA：消费电子协会CEA：Clean Energy AssociatesCEA：资本性支出CEA：中国地震局具体请结合实际情况百度

看看得癌症没有。甲胎蛋白（AFP）、癌胚抗原（CEA） 目前肝癌实验室检查，首选检测项目为AFP，多用放射免疫法（RIA）或AFP单克隆抗体酶免法（EIA）快速测定法检测，原发性肝癌患者血清中AFP的含量，本室用电化学发光法测定，阳性率结果为76.2%，与国内各地的阳性率70%～80%相符合。一般认为AFP>400μg/L时,可对原发性肝癌确定诊断,但约有15%左右原发性肝癌患者血清中AFP始终不高,故AFP不高者不能排除原发性肝癌〔4〕。由于肝细胞肝癌血清中的AFP水平高低又与肝细胞分化程度有关，Ⅰ级肝细胞分化接近正常细胞，故AFP含量尚不足以测出，Ⅳ级者由于分化极差，已失去类似胚胎细胞的机能，也不能从血清中检出AFP，Ⅱ、Ⅲ级肝癌细胞认为是和胚胎肝细胞相似的幼稚细胞，产生AFP阳性率较高，因肝细胞癌的分化程度不同，AFP含量也有差异，特别是约15%左右原发性肝癌患者AFP始终不高，而糖链蛋白CEA及γ-GT，当肝细胞受损及细胞恶变时可有不同程度升高，因而三者结合检测更有意义。 CEA是一种具有人类胚胎抗原特异决定簇的糖类抗原，是重要相关抗原，早期胎儿中由内胚层衍生而来，胃肠道及肝、胰都可合成，因而在原发性肝癌组织中亦存在，可作为肝癌诊断的指标，本文研究结果表明原发性肝癌患者血清CEA水平达（12.8±11.4）ng/ml,显著高于肝炎、肝硬化组及健康对照组（P<0.01），但CEA是一种广谱肿瘤标志物，不能作为诊断某种恶性肿瘤特异性指标，且其单项检测阳性率较低，为52.3%。因此须结合检测才显出其意义。

简单的说是美国AEE推出的一个节能环保行业的一个证书，在欧美国家项目中的认可度非常的高，现在一些楼宇自控，暖通项目等需要节能评估的，就要项目方提供这个证书

苦难显才华,好运隐天资

Adversity reveals genius and fortune conceals it.逆境显才华和财富隐藏它。

vastocean牌子从一开始，Vastocean23就是为了水上旅游而生，由经验丰富的意大利设计师StefanoCaruso亲自操刀主持设计，在保证其安全、专业、耐用的前提条件下，为其倾力打造时尚的外形和舒适宽敞的空间。硬朗而流畅的艇身线条，简约明朗的线型图案，以及多达二十种的配色方案，为其注入了更多活力和可能性，也给予买主更多的选择。与此同时，在这艘只有7米的小船，设计师为其打造了相比同尺寸船型更大的空间，为驾乘者争取更多的舒适感。

irreplaceable的意思是：不可替代的。《Irreplaceable》是美国女歌手碧昂丝演唱的一首流行歌曲，由Ne-Yo等创作，收录于碧昂丝的第二张录音室专辑《B"Day》，于2006年10月26日发行。《Irreplaceable》曾在公告牌百强单曲榜上持续登顶十周，并问鼎2007年公告牌单曲百强榜。《Irreplaceable》起初是Ne-Yo为自己而写的一首乡村歌曲，他是从男性的角度创作的，当Ne-Yo和星门创作团队在考虑这首歌的人声之后，认为男性演唱这首歌会显得歧视女性并有些刻薄，所以这首歌更适合女性来演唱。碧昂斯介绍：1、1993年，以组合天命真女成员身份出道。2003年，开始个人发展，并发行首张个人专辑《Dangerously in Love》。2006年9月4日，发行第2张个人专辑《B"Day》。2008年，发行第3张个人专辑《I Am...Sasha Fierce》。2、2017年，获得全英音乐奖年度国际女歌手奖，并获得美国《福布斯》杂志全球百位名人榜第2位。2018年，与丈夫Jay-Z组成THE CARTERS，并发行专辑《Everything Is Love》。2020年，发行视觉专辑《Black Is King》，由碧昂丝自导自演的同名微电影同时公开。3、碧昂丝在得克萨斯州上小学，并被选入了舞蹈班。同年，她完成了第一次正式舞台表演，演唱了披头士成员John Lennon的《Imagine》并赢得比赛。7岁后，碧昂丝开始获得新闻界的关注，《休士顿纪事》提到她受到当地表演艺术的萨米奖提名一事。

因为DEA"是由三角形DEA翻折而来的,所以三角形DEA"全等于三角形DEA角DA"E=角DAE，角EDA"=角EDA"设角DEC=角1，角A"DE=角ADE=角2，角DA"E=角DAE=角3，角BDA"=角4，角CEA"=角5由图中可以看出角1=角2+角31式角1+角5+角2+角3=180°2式角4=180°-2*角2=（把180°替换为2式）=角1+角5+角2+角3-2*角2（把角1替换为1式）=角2+角3+角5+角2+角3-2*角2=2*角3+角5即角BDA"=2*角A+角CEA"

什么意思！官网查询吗？

notable, 著名的、众所周知的，相当于well-known。noticeable，引人注目的，更强调外观上特殊、突出。noted，被人注意到的，已知的，如果同样用以形容一件事或一个人，其程度比notable差很多。

notable,著名的、众所周知的，相当于well-known。noticeable，引人注目的，更强调外观上特殊、突出。noted，被人注意到的，已知的，如果同样用以形容一件事或一个人，其程度比notable差很多。

百度知道

没有影响喔.这里面是插件.你感觉少了哪个插件的话再去下就好了.

说实话，爱遇禾这个好玩哦！真假难辨，因为太多了，只能说想保住钱包的话，嫒谀合可以一些，因为那些妹纸比较低调。

world ocean race crew世界远洋船员

我那知道

歌曲名:Devil & The Deep Dark Ocean歌手:Nightwish专辑:Oceanborn-Spinefarm RecordsA snowy owl above the haunted watersPoet of ancient godsCries to tell the neverending storyProphecy of becoming floodsAn aura of mystery surrounds herThe lady in brightest whiteSoon the incarnate shall be bornThe Creator of the NightDeep dark is His Majesty"s kingdomA portent of tomorrow"s worldThere shall the liquid give Him powerThe red-eyed unborn lordFatal embrace of the bloodred watersThe cradle of infinite gloomThe spell to master this EarthCarven on an infant"s tomb"I will die for the love of the mermaidHer seduction beauty and scornWelcome to the end of your life- Hail the Oceanborn!""Disgraced is my virginityDeath has woven my wedding dressOh Great Blue breathe the morning dewFor you are the cradle of the image of god""Brave now long rest is sweetWith me here in the deep""I prayed for pleasure wished for lovePrayed for your - ""Never pray for me!""Who the hell are you for meBut a mortal dream to see?""This apathetic life must drownForever just for me""From cradle to coffinShall my wickedness be your passion"We shall come to set the dolphins freeWe shall wash the darkened bloodred seaOur songs will echo over the mountains and seasThe eternity will begin once again in peacehttp://music.baidu.com/song/419523

newlyocean隶属于爱依服。爱依服是多元化生态发展集生产销售于一体的时装品牌，隶属于厦门农和服饰有限公司。经营18-38岁欧日韩等潮流服饰为主营，并兼营各类时尚鞋帽，时装包，皮带，各类服装配饰等。爱依服，快时尚女装品牌，注册于2014年，爱依服是多元化生态发展的集生产，销售于一体的时装品牌，通过布局渠道，实现以街店为主，一二线城市的百货，购物中心以及线上电子商务均衡生态发展。

可以考试介绍CEAC是国家信息化计算机教育认证（Computer Education Authorization Certification）的简称，CEAC项目为信息产业部和原国家信息化推进工作办公室于2002年批准设立的全国性信息技术认证，由CEAC信息化培训认证管理办公室进行统一管理并具体组织实施。项目按照国际规范和信息技术培训标准设计、推出符合中国政府、企业、行业岗位需求的技能型人才培训、解决方案。所有通过考核的学员可以获得“国家信息化培训证书”，证书内页注明所获得相应认证。证书网上查询，全国通用。证书长期有效。CEAC培训课程和题库每两年更新一次。CEAC认证价格经过国家发改委德批准，全国统一标准，约200元左右。CEAC在IT方面的认证有信息化认证。信息化认证的种类：1．动画及多媒体2．多语言速录（中文）①多语言速录技术员（中文）②多语言速录助理工程师（中文）③多语言速录工程师（中文）3．网络应用①CEAC网络管理员－CNA（CEAC Certified Network Administrator）②CEAC网络应用工程师－CNAE（CEAC Certified Network Application Engineer）③CEAC网络应用高级工程师－CSNAE（CEAC Certified Senior Network Application Engineer）4．信息安全①CEAC网络与信息安全系统工程师②CEAC网络与信息安全系统专家③CEAC网络与信息安全系统决策专家5．信息分析①助理信息分析师②信息分析师③高级信息分析师6．图形图像与数码多媒体①CEAC平面设计师－CCGD(CEAC Certified Graphic Designer)②CEAC三维动画工程师－CDAE(CEAC Certified 3D Animation Engineer)③CEAC网页设计师－CCWD(CEAC Certified WEB Designer)④CEAC计算机辅助设计工程师(CEAC Computer Aided Design Engineer)7．室内设计①室内设计工程师8．信息化办公①CEAC办公软件应用专家（CEAC Certified Office Informatization Expert）－COIE②办公软件应用高级专家－CSOIT9．软件开发①CEAC程序员10．数据库①CEAC网络安全管理员②CEAC数据库应用工程师③CEAC数据库应用高级工程师11．三维数字化①三维数字化产品设计师（UG）（3-D Digital Product Designer）②三维数字化产品设计师（Pro/E）（3-D Digital Product Designer)报名条件不同的考试种类、级别有不同的要求和侧重点，考生应结合自身实际情况选报合适的考试科目报名时间报名时间完全由学校和考生决定，每周7天24小时可以随时考试。考试时间考试时间完全由学校和考生决定。考试科目请点击输入图片描述请点击输入图片描述请点击输入图片描述请点击输入图片描述请点击输入图片描述请点击输入图片描述

barely noticeable几乎不引人注意双语例句1And contractors convinced them that vents and ducts and such wouldbe barely noticeable.而且承包方也向他们保证通气口和管道会隐敝得很好，几乎看不到。2As it is only six feet across, it is barely noticeable.由于入口直径只有6英尺，它几乎不可能被人们察觉。

Ocean Rose 是一首歌曲的名字，直译海洋玫瑰，歌词如下She was a silent white rosewho lived in a tall iron towerBarefoot she wandered in her roomdreaming of life and a loverAnd in a night she threw a netinto the ocean wide and deepAnd some of the things she caught in theremade her sad and made her weepA fiery warmth embraced her heartwhen sunrays caught her hairAnd then she looked upon the worldher longing got hard to bearShe was locked in an iron towerwith windows but no doors to be foundOften she listened hard at nightfor a voice in the ocean"s soundAnd voices was mingling with her ownwaves were singing,flee the towerBy the stairway that takes you downfollow the ocean"s song my flowerSilent the rose went downshe was shivering in the dark and the coldThrough in an opening in the wallthe ocean sang as fortoldFloating upon the warm blue seaby the waves to a shore she was ledAmong the trees red roses growand the white rose turned to red...中文歌词失明的光线 几近黯然的叹息 * 低语呢喃里 安静如我 他年清莲 已风化的身躯 噼啪燃烧的火焰 早已作古 且让我在你怀里死去 支离破碎 遍地齑粉 或为脓血 或为飞灰 游走过时光后发酵酝酿 势如野草 在遇到你之后化为春泥 化为丰美 请来吧 携我的手 向春天奔跑 树摇动着手臂 离开泥土 随风而上 请将我击碎 请攻克我多年苦心堆叠的堡垒 请撕裂我的华美冠冕 请让我在闭目之后 依然呼吸你薄荷的清朗 我知道 我属于你 以及飘动的风 流动的空气 扶摇直上 振翅高飞 且让我在你里死去 死去 一切 在这之前 容我暂停 容我挥手 容我告别 彼时的瑰丽如霞 而今徒余苍凉 切莫哭泣 放开你 放开我 放开所有 且看 生生流转 流年如蝶 翩跹而舞 安葬我 用你的手 让我静候 休憩 如奶如蜜的迦南美地 草肥果硕的伊甸花园 等候在你的里面 重新复活 怀一粒莲子的心 且让我死去 若你愿意 请让一枝清瘦的红玫自你手中 轻轻斜依在我的墓前......

conceal和camouflage区别：意思不同、读音不同、用法不同。1、读音不同conceal：英 [kən"siːl] 　 　 美 [kən"siːl]。 　 camouflage：英 ["kæməflɑːʒ] 　 　 美 ["kæməflɑːʒ]。 　 　　2、意思不同conceal：vt. 隐藏；隐瞒；掩盖。camouflage：n. 伪装；掩饰；迷彩服；v. 伪装；欺瞒。3、用法不同He could hardly conceal his joy at his departure.他几乎掩饰不住临行时的喜悦。The animal"s markings provide effective camouflage.这种动物身上的斑纹是很有效的伪装。

In the Late Proterozoic，profound changes occurred that included the break-up of the supercontinent Rodinia，geographically extensive glaciations，dramatic isotope excursions of，for example，strontium and carbon Jacobsen and Kaufman，this volume on a scale unprecedented in the Phanerozoic，intervals with high abundance of acritarchs suggesting alternating periods of low and high organic productivity，and the emergence of trace，body and skeletonized fossils. Close to the Precambrian-Cambrian boundary， other dramatic biotic events continue that have been described as the Cambrian Explosion. Extensive biomineralization of soft tissue in many major groups of organisms resulted in diverse skeletonized faunas being preserved in the fossil record. Some new biochemical evidence suggests that the initial radiation of major clades of metazoans began about 1200 Ma rather than about 600 Ma ago. If so，what processes or threshold conditions existed to suppress the abundance，size，and diversity radiation for about 600 Ma from 1200 to 600 Ma? Answers may lie in the chemical nature of these oceans. Martin has argued for superoligotrophic oceans for most of the Early Paleozoic. He considered that the oceans were predominantly stratified and only sluggishly circulating; as a consequence there was limited mixing and transfer of nutrients from the deep ocean to surface waters for utilization by organisms ( Fig. 1) . If the oxygen and CO2levels of about 0. 2，2 and 20 times the present atmospheric levels，respectively，for the Cambrian are correct，as interpreted by Berner，then a critical threshold factor for respiration and for ecological expansion would have been the O2levels in the surface and deeper part of the oceans. The interplay of anoxic waters with surface waters somewhat enriched in oxygen is likely to have been a critical factor in the waves of extinctions evident in Cambrian and early Ordovician rocks. Such encroachment of anoxic waters onto carbonate platforms was considered by Zhuravlev and Wood to cause the mid-Early Cambrian Botomian extinction and later the periods of eutrophication to be characterized by phytoplankton blooms. Using Sr and C isotopes data from the Upper Cambrian，Saltzman et al. argued that catastrophic ocean overturning produced similar periodic，widespread，anoxic conditions. Such pulses may well explain the pattern of trilobite extinctions that were used to define biomere boundaries by Palmer.Progressive ventilation of the deeper oceans appears to have occurred through the Ordovician and Silurian. Attempts to deduce the pattern of oceanic circulation for intervals throughout these two periods have been made by Wilde and Wilde et al. ，respectively，using the paleogeographic reconstructions of Scotese and McKerrow. The superoligotrophic conditions of these oceans and the warm greenhouse climate state throughout the Early Paleozoic were only interrupted in the Ashgill and early Llandovery ( Late Ordovician—Early Silurian) when a continental glaciation developed across North Africa that was then located near the southern pole. The onset of aggressive thermohaline circulation both chilled and ventilated the deep ocean with several glacial phases occurring over about a 10 Ma interval，but with the main Hirnantian phase perhaps lasting only for a few hundred thousand years. The cause of this short-lived icehouse state within such a long 200 Ma period of greenhouse conditions is still speculative and some authors have related it to the passage of part of Gondwana over the south polar region or to the brief drawdown of atmospheric CO2. Even as greenhouse states prevailed through much of the Silurian，detailed analysis on conodont microfossil distributions and related microfacies changes have suggested to Jeppsson and Aldridge et al. that the Silurian ocean state and associated climate was characterized by alternating primo and secundo states with periodic，but rapid turnover intervals. The principal differences being a warm humid phase vs. a drier cooler phase that resulted in significantly different lithologies and reef tracts across the low latitude carbonate platforms. Fig. 1 Indices of ancient nutrient fluxes and productivity through the last 650 MaAnother seemingly important factor in paleoceanography is the changing pattern of eustasy. Sensitive records are preserved on the carbonate platforms and examination of several cratons allows a global pattern to emerge for the Ordovician and Silurian. Major transgressions produced as epicontinental seas that generated important sites of warm，dense hypersaline waters and the periodic development and then closure of this system with transgressive and then regressive events has not yet been fully accommodated into paleoceanographic models. Such oscillations certainly produced major global bio-events. For the Late Ordovician，the Caradoc transgression was the largest of the Phanerozoic and may have been generated by much higher rates of sea-floor spreading and / or the occurrence of a mantle superplume.There is a marked contrast in the studies of paleoceanography of the Early Paleozoic with those of the Mesozoic and Cenozoic as noted initially. The application of a wide range of isotope proxy data with DSDP and ODP core samples and detailed analysis of abundant cores and outcrop studies in well preserved sedimentary basins，such as the Western Interior Seaway of North America，have allowed increasingly sophisticated interpretations of paleoceanography. Periods of anoxia，of less than 1 Ma duration have been recognized in all major oceans for the Late Barremian to Late Aptian of the Early Cretaceous. Peak oxygen deficiency corresponded to highly eutrophic conditions whereas less intense dysoxic / anoxic intervals were characteristic of oligotrophic conditions. The Albian and part of the Cenomanian were the warmest parts of the Cretaceous at a time when there appears to have been four times the present atmospheric level of CO2. Some authors have argued that ready transfer of heat from the equator to the polar regions reduced the latitudinal gradient and fostered a warm green-house state. Larson advocated the presence of a mid-Cretaceous mantle superplume in the western Pacific that produced the Ontong Java Plateau and this model was elaborated upon by Caldeira and Rampino to explain the widespread black shales，high organic productivity and oil accumulation ( Fig. 2) . Even within the Cretaceous there are considerable changes in oceanic temperature gradients. Huber et al. showed that during the Coniacian—Santonian the difference between low and high latitude surface- water paleotemperatures was in the range of 0—4℃ . As cooling increased towards the end of the period，the temperature difference increased to about 14℃ . Detailed investigations of the Cretaceous biotas have revealed complex patterns of marine biogeography that primarily mirror the changing major water masses and current systems along with the modifications to the Tethys Seaway and the Western Interior Seaway of North America. The open equatorial circulation around much of the globe via the Tethyan Seaway and the presence of wide shallow shelves on which warm saline waters were generated seem to be critical components to maintain the ultra warm greenhouse state at this time.Fig. 2 Inferred mid-Cretaceous mantle superplume showing increased ocean crust generation， sea level，black shales and related increases in ocean temperature and oil generation. These changes correspond to an interval free of magnetic reversals.In addition to the Cretaceous deep oceans，particularly Tethys，Pacific and opening Atlantic， large shelf seas developed as in Europe and the Western. Interior Sea of North America. The latter has received considerable attention because of the large stratigraphic database developed through oil exploration. In the Western Canada Sedimentary Basin，over 150，000 wells have been drilled in Alberta alone，with many aimed at the Cretaceous or passing to Devonian targets. The Cretaceous Seaway initially spread north from the Gulf of Mexico and south from the Beaufort Sea， meeting in Albian time. The sea was constrained on the west by emerging tectonic forelands tied to major Cordilleran orogenic phases and terrane accretion on the Pacific margin; on the east it lapped progressively eastwards on a largely peneplained Canadian Shield. Tectonic deformation generated an asymmetrically subsiding foreland basin and an eastward migrating peripheral bulge. From sedimentological and paleontological studies the seaway is estimated to have been up to 1000 m deep in the west-central corridor. The western margin was subjected to much clastic fill from the deforming foreland，transported by complex river systems. Volcanoes contributed extensive， eastwardly transported ash falls with over 200 bentonites in the Cretaceous sequence，which，with detailed biostratigraphy，have provided a remarkably detailed chemostratigraphy to unravel the changes to the seaway through time.Within this overall framework，there have been several recent attempts to understand and model the paleoceanography of this north-south seaway. Kaufmann initially tried to discriminate the inflowing north and south waters from surface freshwater caps derived from rivers mainly flowing from the emerging Cordilleran foreland. More recent attempts have modelled current flows within the sea-way. Jewell noted that salinity stratification in the seaway could have been established rapidly. Slingerland et al. proposed that river flux was important and likely controlled the strong counterclockwise gyre occupying the entire north-south extent of the seaway.In the Cenozoic，an early phase of global warming ( Paleocene—Eocene) was followed by a progressive but variable decline in mean annual temperature ( Oligocene—Recent) . The onset of glaciation occurred first in Antarctica close to the Eocene—Oligocene boundary ( ca. 34 Ma) . Major Arctic glaciation appears to have been initiated in the late Pliocene ( ca. 2. 8 Ma) . The Cenozoic provides an opportunity to investigate the processes of changeover from a greenhouse to icehouse state. Fundamental questions remain unresolved about the initiation and maintenance of these two states and of the complex feedback loops in the climate system. Of particular interest are the processes of heat transfer to the high latitudes during a greenhouse state and their collapse during the icehouse state. Two possible principal causes have been advanced， possibly interrelated. Firstly，decreased atmospheric CO2partly derived from the weathering of uplifted crustal rocks during the late phases of alpine orogeny ( e. g. ， Himalayan， Alps， Andes， Cordillera) . Secondly，there was substantially altered ocean circulation，particularly the onset of the deep ocean conveyor belt with thermohaline circulation derived from sinking of cold water in the North Atlantic. In this latter case，the pattern of ocean circulation is strongly affected by paleogeographic barriers such as the opening of the Drake Passage or closing of the Panama Isthmus.For the early Cenozoic greenhouse state，O"Connell et al. modelled atmospheric circulation conditions. In one experiment，they showed that under extreme zonal conditions evaporation may have substantially exceeded precipitation leading to the generation of very saline water. Zachos et al. discussed early Cenozoic temperatures from the oceanographic view，and Hovan and Rea used ODP data to examine the particular changes at the Paleocene / Eocene boundary. Here，they noted the dramatic changes that occur over a period of about 1. 2 Ma including: extinction of some benthic foraminifera and changes in calcareous plankton assemblages，oceanic warming，decrease in carbon isotope ratios，reduction in wind strength，an increase in hydrothermal activity. This same change is found in the continental record and is marked by the first appearance of several important modern mammalian orders. The Paleocene and early Eocene climates were controlled primarily by large scale meridional energy transport through the oceans rather than the atmosphere and in part influenced by tectonic events. Hovan and Rea showed that a strong reduction in Paleocene / Eocene wind stress occurs in both hemispheres at the boundary，related to decreased latitudinal thermal gradients produced by a more effective poleward heat transport via the deep ocean.There were dramatic changes to these greenhouse conditions at the Eocene / Oligocene boundary，including: fall in oceanic bottom water temperatures; 1 km drop in the calcium compensation depth in the Pacific; increase in deep sea unconformities; extinctions of planktonic foraminifera. These were apparently related to sudden high latitude cooling and enhanced oceanic thermohaline circulation. The onset of Antarctic glaciation occurred at about 34. 5 Ma seemingly closely related to the opening of the Drake Passage ( between South America and Antarctica) : surface and intermediate water circulation is documented by paleontology at this time，with other geologic evidence suggesting complete opening and deepwater circulation by about 30 Ma. These circulation changes induced a new position for the polar front and strongly influenced the pattern of upwelling and productivity.The late Neogene marks the onset of Arctic glaciation and enhanced global cooling. A significant oceanographic circulation event during this time was the full closure，evaporation and then reflooding of the Mediterranean Sea; the Messinian Event ( ca. 8—5 Ma ) in the late Miocene. The more recent work based on defined sequence stratigraphy and chronostratigraphy has shown that there were two distinct phases of evaporite accumulation，each associated with a sea-level drop that were in turn likely to be of glacio-eustatic origin. Salt a

In the Late Proterozoic，profound changes occurred that included the break-up of the supercontinent Rodinia，geographically extensive glaciations，dramatic isotope excursions of，for example，strontium and carbon Jacobsen and Kaufman，this volume on a scale unprecedented in the Phanerozoic，intervals with high abundance of acritarchs suggesting alternating periods of low and high organic productivity，and the emergence of trace，body and skeletonized fossils. Close to the Precambrian-Cambrian boundary， other dramatic biotic events continue that have been described as the Cambrian Explosion. Extensive biomineralization of soft tissue in many major groups of organisms resulted in diverse skeletonized faunas being preserved in the fossil record. Some new biochemical evidence suggests that the initial radiation of major clades of metazoans began about 1200 Ma rather than about 600 Ma ago. If so，what processes or threshold conditions existed to suppress the abundance，size，and diversity radiation for about 600 Ma from 1200 to 600 Ma? Answers may lie in the chemical nature of these oceans. Martin has argued for superoligotrophic oceans for most of the Early Paleozoic. He considered that the oceans were predominantly stratified and only sluggishly circulating; as a consequence there was limited mixing and transfer of nutrients from the deep ocean to surface waters for utilization by organisms ( Fig. 1) . If the oxygen and CO2levels of about 0. 2，2 and 20 times the present atmospheric levels，respectively，for the Cambrian are correct，as interpreted by Berner，then a critical threshold factor for respiration and for ecological expansion would have been the O2levels in the surface and deeper part of the oceans. The interplay of anoxic waters with surface waters somewhat enriched in oxygen is likely to have been a critical factor in the waves of extinctions evident in Cambrian and early Ordovician rocks. Such encroachment of anoxic waters onto carbonate platforms was considered by Zhuravlev and Wood to cause the mid-Early Cambrian Botomian extinction and later the periods of eutrophication to be characterized by phytoplankton blooms. Using Sr and C isotopes data from the Upper Cambrian，Saltzman et al. argued that catastrophic ocean overturning produced similar periodic，widespread，anoxic conditions. Such pulses may well explain the pattern of trilobite extinctions that were used to define biomere boundaries by Palmer.Progressive ventilation of the deeper oceans appears to have occurred through the Ordovician and Silurian. Attempts to deduce the pattern of oceanic circulation for intervals throughout these two periods have been made by Wilde and Wilde et al. ，respectively，using the paleogeographic reconstructions of Scotese and McKerrow. The superoligotrophic conditions of these oceans and the warm greenhouse climate state throughout the Early Paleozoic were only interrupted in the Ashgill and early Llandovery ( Late Ordovician—Early Silurian) when a continental glaciation developed across North Africa that was then located near the southern pole. The onset of aggressive thermohaline circulation both chilled and ventilated the deep ocean with several glacial phases occurring over about a 10 Ma interval，but with the main Hirnantian phase perhaps lasting only for a few hundred thousand years. The cause of this short-lived icehouse state within such a long 200 Ma period of greenhouse conditions is still speculative and some authors have related it to the passage of part of Gondwana over the south polar region or to the brief drawdown of atmospheric CO2. Even as greenhouse states prevailed through much of the Silurian，detailed analysis on conodont microfossil distributions and related microfacies changes have suggested to Jeppsson and Aldridge et al. that the Silurian ocean state and associated climate was characterized by alternating primo and secundo states with periodic，but rapid turnover intervals. The principal differences being a warm humid phase vs. a drier cooler phase that resulted in significantly different lithologies and reef tracts across the low latitude carbonate platforms. Fig. 1 Indices of ancient nutrient fluxes and productivity through the last 650 MaAnother seemingly important factor in paleoceanography is the changing pattern of eustasy. Sensitive records are preserved on the carbonate platforms and examination of several cratons allows a global pattern to emerge for the Ordovician and Silurian. Major transgressions produced as epicontinental seas that generated important sites of warm，dense hypersaline waters and the periodic development and then closure of this system with transgressive and then regressive events has not yet been fully accommodated into paleoceanographic models. Such oscillations certainly produced major global bio-events. For the Late Ordovician，the Caradoc transgression was the largest of the Phanerozoic and may have been generated by much higher rates of sea-floor spreading and / or the occurrence of a mantle superplume.There is a marked contrast in the studies of paleoceanography of the Early Paleozoic with those of the Mesozoic and Cenozoic as noted initially. The application of a wide range of isotope proxy data with DSDP and ODP core samples and detailed analysis of abundant cores and outcrop studies in well preserved sedimentary basins，such as the Western Interior Seaway of North America，have allowed increasingly sophisticated interpretations of paleoceanography. Periods of anoxia，of less than 1 Ma duration have been recognized in all major oceans for the Late Barremian to Late Aptian of the Early Cretaceous. Peak oxygen deficiency corresponded to highly eutrophic conditions whereas less intense dysoxic / anoxic intervals were characteristic of oligotrophic conditions. The Albian and part of the Cenomanian were the warmest parts of the Cretaceous at a time when there appears to have been four times the present atmospheric level of CO2. Some authors have argued that ready transfer of heat from the equator to the polar regions reduced the latitudinal gradient and fostered a warm green-house state. Larson advocated the presence of a mid-Cretaceous mantle superplume in the western Pacific that produced the Ontong Java Plateau and this model was elaborated upon by Caldeira and Rampino to explain the widespread black shales，high organic productivity and oil accumulation ( Fig. 2) . Even within the Cretaceous there are considerable changes in oceanic temperature gradients. Huber et al. showed that during the Coniacian—Santonian the difference between low and high latitude surface- water paleotemperatures was in the range of 0—4℃ . As cooling increased towards the end of the period，the temperature difference increased to about 14℃ . Detailed investigations of the Cretaceous biotas have revealed complex patterns of marine biogeography that primarily mirror the changing major water masses and current systems along with the modifications to the Tethys Seaway and the Western Interior Seaway of North America. The open equatorial circulation around much of the globe via the Tethyan Seaway and the presence of wide shallow shelves on which warm saline waters were generated seem to be critical components to maintain the ultra warm greenhouse state at this time.Fig. 2 Inferred mid-Cretaceous mantle superplume showing increased ocean crust generation， sea level，black shales and related increases in ocean temperature and oil generation. These changes correspond to an interval free of magnetic reversals.In addition to the Cretaceous deep oceans，particularly Tethys，Pacific and opening Atlantic， large shelf seas developed as in Europe and the Western. Interior Sea of North America. The latter has received considerable attention because of the large stratigraphic database developed through oil exploration. In the Western Canada Sedimentary Basin，over 150，000 wells have been drilled in Alberta alone，with many aimed at the Cretaceous or passing to Devonian targets. The Cretaceous Seaway initially spread north from the Gulf of Mexico and south from the Beaufort Sea， meeting in Albian time. The sea was constrained on the west by emerging tectonic forelands tied to major Cordilleran orogenic phases and terrane accretion on the Pacific margin; on the east it lapped progressively eastwards on a largely peneplained Canadian Shield. Tectonic deformation generated an asymmetrically subsiding foreland basin and an eastward migrating peripheral bulge. From sedimentological and paleontological studies the seaway is estimated to have been up to 1000 m deep in the west-central corridor. The western margin was subjected to much clastic fill from the deforming foreland，transported by complex river systems. Volcanoes contributed extensive， eastwardly transported ash falls with over 200 bentonites in the Cretaceous sequence，which，with detailed biostratigraphy，have provided a remarkably detailed chemostratigraphy to unravel the changes to the seaway through time.Within this overall framework，there have been several recent attempts to understand and model the paleoceanography of this north-south seaway. Kaufmann initially tried to discriminate the inflowing north and south waters from surface freshwater caps derived from rivers mainly flowing from the emerging Cordilleran foreland. More recent attempts have modelled current flows within the sea-way. Jewell noted that salinity stratification in the seaway could have been established rapidly. Slingerland et al. proposed that river flux was important and likely controlled the strong counterclockwise gyre occupying the entire north-south extent of the seaway.In the Cenozoic，an early phase of global warming ( Paleocene—Eocene) was followed by a progressive but variable decline in mean annual temperature ( Oligocene—Recent) . The onset of glaciation occurred first in Antarctica close to the Eocene—Oligocene boundary ( ca. 34 Ma) . Major Arctic glaciation appears to have been initiated in the late Pliocene ( ca. 2. 8 Ma) . The Cenozoic provides an opportunity to investigate the processes of changeover from a greenhouse to icehouse state. Fundamental questions remain unresolved about the initiation and maintenance of these two states and of the complex feedback loops in the climate system. Of particular interest are the processes of heat transfer to the high latitudes during a greenhouse state and their collapse during the icehouse state. Two possible principal causes have been advanced， possibly interrelated. Firstly，decreased atmospheric CO2partly derived from the weathering of uplifted crustal rocks during the late phases of alpine orogeny ( e. g. ， Himalayan， Alps， Andes， Cordillera) . Secondly，there was substantially altered ocean circulation，particularly the onset of the deep ocean conveyor belt with thermohaline circulation derived from sinking of cold water in the North Atlantic. In this latter case，the pattern of ocean circulation is strongly affected by paleogeographic barriers such as the opening of the Drake Passage or closing of the Panama Isthmus.For the early Cenozoic greenhouse state，O"Connell et al. modelled atmospheric circulation conditions. In one experiment，they showed that under extreme zonal conditions evaporation may have substantially exceeded precipitation leading to the generation of very saline water. Zachos et al. discussed early Cenozoic temperatures from the oceanographic view，and Hovan and Rea used ODP data to examine the particular changes at the Paleocene / Eocene boundary. Here，they noted the dramatic changes that occur over a period of about 1. 2 Ma including: extinction of some benthic foraminifera and changes in calcareous plankton assemblages，oceanic warming，decrease in carbon isotope ratios，reduction in wind strength，an increase in hydrothermal activity. This same change is found in the continental record and is marked by the first appearance of several important modern mammalian orders. The Paleocene and early Eocene climates were controlled primarily by large scale meridional energy transport through the oceans rather than the atmosphere and in part influenced by tectonic events. Hovan and Rea showed that a strong reduction in Paleocene / Eocene wind stress occurs in both hemispheres at the boundary，related to decreased latitudinal thermal gradients produced by a more effective poleward heat transport via the deep ocean.There were dramatic changes to these greenhouse conditions at the Eocene / Oligocene boundary，including: fall in oceanic bottom water temperatures; 1 km drop in the calcium compensation depth in the Pacific; increase in deep sea unconformities; extinctions of planktonic foraminifera. These were apparently related to sudden high latitude cooling and enhanced oceanic thermohaline circulation. The onset of Antarctic glaciation occurred at about 34. 5 Ma seemingly closely related to the opening of the Drake Passage ( between South America and Antarctica) : surface and intermediate water circulation is documented by paleontology at this time，with other geologic evidence suggesting complete opening and deepwater circulation by about 30 Ma. These circulation changes induced a new position for the polar front and strongly influenced the pattern of upwelling and productivity.The late Neogene marks the onset of Arctic glaciation and enhanced global cooling. A significant oceanographic circulation event during this time was the full closure，evaporation and then reflooding of the Mediterranean Sea; the Messinian Event ( ca. 8—5 Ma ) in the late Miocene. The more recent work based on defined sequence stratigraphy and chronostratigraphy has shown that there were two distinct phases of evaporite accumulation，each associated with a sea-level drop that were in turn likely to be of glacio-eustatic origin. Salt a

用字母组成单词？cabbage卷心菜

英文原文：bounce a ball英式音标：[baʊns] [ə; eɪ] [bɔːl] 美式音标：[baʊns] [e] [bɔl]