Optical investigations of dust storms during U.S.S.R.-U.S. experiments in Tadzhikistan, 1989

The results of studies on dust aerosol optical properties obtained during the U.S.S.R.-U.S. experiment are discussed. The ground-based and aircraft measurements carried out during the experiment allow the estimation of characteristic values of aerosol optical depth, aerosol light-scattering coefficients, the degree of linear polarization, and aureole phase functions for different atmospheric conditions in Central Soviet Asia. Two dust storms were observed for which the recorded aerosol optical depth at λ = 0.55 μm {τ_a(0.55)} reached 1.5 on 16 and 17 September 1989, and 3.5 on 20 and 21 September 1989. The optical characteristics (spectral dependence of the optical depth, degree of linear polarization) were similar for two dust episodes.     

劳伦斯·洛克菲勒

劳伦斯·洛克菲勒1910年5月生于纽约,他是叱咤商界和慈善界的洛克菲勒家族第三代传人,是著名的小约翰·D·洛克菲勒六个孩子当中的老四。他1932年毕业于普林斯顿大学,后在哈佛大学学习了两年法律。劳伦斯·洛克菲勒于2004年7月10日去世,享年94岁。这位老人的去世引起了全球的关注,并因此引发了一系列关于他生平事     

美国的环境会计

本文介绍了美国环境会计中补偿成本和控制预防成本会计的相关标准和账务处理方法，希望能够对我国的企业在实际工作中做好有关环境成本的核算，计量和确诊所借鉴，促进我国环境会计健康发展。     

中美气候变化论坛

由美国加州大学伯克利分校和北京大学联合主办的中美气候变化论坛于5月23日至24日在旧金山开幕．有来自中美两国以及欧洲等地的专家学者近200人参加了论坛。     

Soil crust formation by dust deposition at Shaartuz,Tadzhik, S.S.R.

The shrub-steppe area near Shaartuz, Tadzhik, S.S.R., is shown to be a net accumulator of dust despite being an occasional source of dust. For the accumulation of the dust to form the observed surface crust, a net deposition of about 290–490 g m⁻² yr⁻¹ of particles smaller than 20 μm is required, depending on the duration of the deposition period. The particles smaller than 20 μm are mixed with particles brought up from the sandy material below the surface crust by bioturbation and are incorporated into the surface crust. Measurements during the 16 and 20 September 1989 dust storms provided a total deposition of 41.1 g m⁻² of particles smaller than 20 μm. Because 10–30 dust storms are observed at Shaartuz, the measured average dust storm deposition would yield 206–617 g m⁻² yr⁻¹. This range of deposition is of the order of that needed to provide a mass balance for the observed crust formation. Cryptogams (including algae, lichen, and moss) and rainwater are the main agents of incorporation of the aeolian dust into a stable soil crust. The role that the vascular plants played at the Shaartuz site was to reduce the rate of soil movement to levels where the cryptogamic crusting was possible. the observed mechanisms of dust deposition followed by crust incorporation are possibly an important processes in loess formation in Central Asia.     

Five years' experience of prenatal diagnosis of cystic fibrosis in the former U.S.S.R.

From a total of 490 cystic fibrosis (CF) high-risk families under supervision (mostly Russian Slavs from the European part of the country), DNA data including both direct screening for some CF gene(CFTR)mutations(deIF508, G551D and 1677delTA) and allelic polymorphism studies with tightly CF linked DNA markers were collected from 261 families. All full families (129) and 86 CF families with a deceased index child were found to be either fully (42 per cent) or partially (40 per cent) informative for DNA analysis. Prenatal diagnosis (PD) was carried out in 161 CF families. Microvillar enzyme (MVE) assay was applied to all 140 PD at the second trimester either as a single test (88) or in conjunction with DNA analysis (52). The frequency of false-negative results of the MVE assay was 1.3 percent and that of false-positive results, as judged by the albumin meconium test, was 5.0 per cent. Ambiguous results of MVE analysis were found in 30 cases, 12 of which were verified by DNA analysis. Molecular diagnosis of CF at the first trimester was carried out in 21 cases and four pregnancies were terminated. Altogether, 39 pregnancies with a predicted high risk of CF fetuses were terminated. The low average frequency of delF508 in CF chromosomes of Russian Slavs (50 per cent), its remarkable inter-population variation, and the significant proportion of at-risk families without an affected child determine the necessity of combined molecular and biochemical (MVE assay) approaches for efficient prenatal diagnosis of CF in the former U.S.S.R.     

美国海军舰艇命名体系研究

美国海军舰艇命名体系由任命前缀、舰艇名称、分类代号、舷号4类要素构成,首先分析了每类要素对于命名体系的贡献,然后基于美国海军舰艇命名体系,以美国海军舰艇名册为数据源,通过要素提取、规则建立等步骤分析美国海军现役舰艇组成。经过分析,美国现役715艘舰艇分为战斗舰、辅助舰、战斗艇、支援艇、未在分类代号中定义等5大类67类型177级别,通过对比基于类型与级别规则、基于任命前缀规则的结果挖掘出美国海军现役舰艇组成规律。     

美国的环境标准

介绍了美国环境标准的法律地位与作用以及大气环境标准、水环境标准、固体废物处理场标准,并分析了其特点。      

中美地热能资源管理比较探析

地热资源作为一种清洁能源在欧美国家已经普遍获得立法肯定,并建立起了较为成熟的法律规则。美国在地热资源的界定、地热财税制度、国有资源的保护等方面进行的立法探索,为中国当前的地热资源开发提供了良好的制度借鉴。在欧美国家的实践基础上,中国资源立法可以籍此完善国有资源的产权结构,构建起科学的地热资源用益机制。     

在美国看水

在中国,各种媒体关于水污染事件的报道屡见不鲜,污染导致的水质性缺水已成为制约我国经济社会发展的瓶颈,甚至是迈向现代化进程中绕不过去的一道坎儿.然而,远在太平洋另一端的美国,情况又是怎样呢?笔者近期的美国之行也许能给人启示.     

美国国家海洋自然保护区监测及其对我国的启示

着重介绍了美国国家海洋自然保护区的监测目标、理论基础、监测内容。监测是掌握海洋自然保护区状况与发展趋势的重要手段,是海洋自然保护区建设与管理的重要工作内容。美国国家海洋自然保护区的保护目的和所保护的资源类型同我国的海洋自然保护区相似。且监测水平与管理机制处于世界领先水平。了解研究美国的先进经验,对促进我国海洋自然保护区的监测工作具有很好的借鉴作用。     

中美二噁英相关标准的比较

总结分析了中美两国二噁英有关标准的特点。我国二噁英相关的标准体系有待完善,主要集中在重点行业的烟气排放标准方面。美国二噁英相关标准体系较为完善,以风险评估为重点,二噁英排放源涉及的行业划分细致。排放标准分级明显,技术导向明显。通过对比分析指出,我国应继续深化重点行业的烟气排放控制的策略。加强二噁英风险评估的基础性研究工作,以减排技术为基础,强化分级管理的思路,并针对不同排放源细化二噁英的标准。     

美国污染物排放标准对制定我国锡工业污染物排放标准的启示

在分析美国污染物排放标准体系和排放标准法制化管理的基础上,提出我国锡工业污染物排放标准制定中应注意的事项。并指出我国污染物排放标准不适合用标准化管理,应借鉴美国的经验,走法制化管理的道路,通过健全的法律机制,保障锡工业污染物排放标准的制定和实施。     

美军基于模拟仿真的加速腐蚀系统

美军最新开发了全尺寸车辆腐蚀模拟仿真和建模工具,称为加速腐蚀专家模拟器(ACES),它与实际加速腐蚀耐久性试验(ACDT)数据高度相关.该系统引入现有全尺寸车辆3D几何模型,进行综合检测以确定有无故障并报告补救措施;采用了基于腐蚀和涂层失效机理分析的各种人工智能解决方案;使用了由专家、ACDT、实验室试验数据以及现场观...     

英汉对比与文化差异--浅谈跨文化交际中的语言差异引起的误译

文化差异会使得跨文化交际产生困难、误解和矛盾.对文化差异必要的了解在成功地进行跨文化交际中起到重要的作用.本文归纳分析了文化差异在语言使用中的表现及造成误解和误译的原因,提出了进行跨文化交际应具备的基础.     

美国机动车污染控制(下)

移动源污染控制政策设计 政策工具的范围由于一定的理由，设计和执行机动车污染控制政策特别困难。首先，从根本上说，控制移动源污染不同于控制固定源污染，因为高度移动的污染源数量奇多，每个体污染排放又相对较少。第二，用于控制移动源污染的各种政策措施还没有得到与固定源替代政策相同的注意力。使人意外的是，大多数国家的法规仍然主要依靠针对生产厂商的新车排放标准。第三，在使用刺激手段以采用环保型交通产品时，人们对针对机动车生产厂商的法规是否比指向使用者的措施是否更有效尚不确定。最后，机动车在现代生活方式中的统治…     

美国空间环境保障技术发展研究

在介绍世界空间环境研究的基础上,详细分析了美国/美军空间环境研究和应用服务保障建设。结果表明,美国/美军具有较强的空间环境探测能力、先进的空间环境预警预报技术和高效的空间环境效应评估分析能力,空间环境保障技术和保障服务能力实属世界一流。     

美国沿海城市禁烟势态高涨

1994年3月，美国加利福尼亚州的立法委员会通过和颁布”餐馆，酒吧内一律不准吸烟”的法令。3个月后，又把禁烟范围扩大到政府机关大楼周边地区和公共活动场地，。到2003年9月，加利福尼亚州沿海城市索拉纳滩(Solana Beach)又把禁烟范围率先扩大到海滨沙滩和游泳场。2004年3月，圣克利门蒂(San Clemente)和圣莫尼卡(Senta Monica)两座沿海城市议会投票，     

Responding to scientific uncertainty in U.S. forest policy

Scientific uncertainty plays a significant role in forest policy and planning. Ecological complexity, the gap between science and policy, and public perceptions of science all contribute to the challenge of dealing with scientific uncertainty. This paper provides an overview of the role of scientific uncertainty in U.S. forest policy and an analysis of the requirements for responding to uncertainty under the National Forest Management Act, National Environmental Policy Act, and Endangered Species Act. The analysis includes a review of a broad range of literature and relevant statutory and regulatory language, along with several illustrative examples of case law. Findings include that all three laws allow for considerable agency discretion in cases of scientific uncertainty, and none prescribes a particular response to uncertainty. Approaches such as adaptive management may provide a way to proceed despite uncertainty, and while this approach represents something of a new paradigm in public land management, it is not incompatible with the current legal framework. The article concludes with recommendations, such as increased transparency and changes in the norms of judicial review, for increasing the accountability of decisions when uncertainty is involved. Also considered are other suggestions, such as peer-review, Daubert standards, and Bayesian inference techniques.