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1.
Human space exploration is not considered a strategic priority in the United Kingdom at present. However the UK would benefit from participating in human spaceflight, for both scientific and social reasons. From the point of view of medical science there are many parallels between the physiology of spaceflight and terrestrial disease processes, and studies of the response of astronauts to long-duration spaceflight can therefore help in the development of therapeutic strategies on Earth. On the social side, human spaceflight is an attractive vehicle for stimulating the interest of young people in science and engineering, something that must be of value for an aspiring ‘knowledge-based’ economy.  相似文献   
2.
PALEOSOLSOFSANDYLANDSANDENVIRONMENTALCHANGESINTHEWESTERNPARTOFNORTHEASTPLAINOFCHINAWESTERNDURINGHOLOCENE¥QiuShanwen(裘善文)LiQus...  相似文献   
3.
根据第四纪地层内孢粉组合和动物群等新资料恢复了我国东部各大区域第四纪各个时期的自然环境特征,其温暖期与干冷期的交替与深海沉积O~(18)温度变化趋势大致对应。庐山三次“冰期冰碛层”内孢粉组合表明均为温暖湿润针阔叶混交林景观,而不是寒冷的冰川环境。  相似文献   
4.
Deborah F. Shmueli 《Geoforum》2008,39(6):2048-2061
When applied to environmental concerns, framing offers a rigorous conceptual and analytic approach with potentially practical significance for dealing with complex issues relevant to geography. The purpose of this article is to introduce framing concepts, typology and modes of analysis to address issues which geographers commonly treat: disputes over land ownership and uses, competition for water resources, cultural clashes over control of territory and resources and the impact of spatial patterns and structures when siting noxious sites. Framing analysis is applied to three cases of environmental conflict in Israel and, more generally, for understanding conflicts revolving around the management of human habitats in relation to the physical environment.  相似文献   
5.
本文讨论了北黄海11个柱状岩芯样的颗粒物(<0.063mm)中重金属的分布,采用统计学方法对Cu,Ph,Zn和Cd进行态性检验,用柱样稳定段(拐点以下)作为背景段,获得重金属环境背景值.  相似文献   
6.
南黄海自生黄铁矿成因及其环境指示意义   总被引:12,自引:2,他引:12  
样品为1989年采自南黄海,利用显微镜,电子显微镜,电子探针和化学分析方法,对自生黄铁矿的形态,成份和同位素特征进行研究,在此基础上就其成因与形成环境的关系进行初步探讨。研究结果表明,自生黄铁矿集合体形态可以分为聚莓,单莓和细粒3种,霉体特征的形态是早期成岩作用阶段沉积物随机堆积的结果,可以作了沉积成因黄铁矿的形态标型黄铁矿微量成份特征显示其沉积成因,同时亦表现对泥质沉积物地球化学背景值的继承性,  相似文献   
7.
Extensive potassium and phosphorous-rich mineralization occurs on the outer continental shelf of the southern and west coasts of South Africa and Nambia. This article reviews the potential of exploiting these deposits in an environmentally sound manner for the manufacture of fertilizer. At present, reserves of potash and phosphate fertilizer are exploited from terresterial deposits, the majority being surface mined. The use of fertilizer in South Africa has shown no growth in the past 13 years, and, in some years, usage has even declined. On average, over the last decade, South Africa has consumed 2 million Mt of fertilizer (including nitrogen) per annum, the vast majority of phosphate fertilizer being produced by FOSKOR from the Phalaborwa Igneous Complex. Potash fertilizer is imported into South Africa. Although fertilizer consumption is expected to decrease in the short-term, there are good future prospects for the domestic and international fertilizer market. Considerable research into both glauconitic (containing K 2 O) and phosphatic deposits along the southern African continental shelf indicate that these sedimentary deposits have a complex genesis and mineralization. Of the total K 2 O reserves of 1300 million Mt on the southern African margin, 1000 million Mt is located off the southern African west coast, and the remainder situated on the Agulhas Bank. The largest glauconite concentration ( ±300 million Mt K 2 O) off southern Africa lies west of Saldanha Bay, South Africa. The distribution of P 2 O 5 off southern Africa is dominated by the vast deposit between Walvis Bay and Luderitz, Nambia. This reserve is estimated to contain 1000 million Mt of greater than 5% P 2 O 5 in a relatively small area of about 10000 km2. The phosphorite deposit south of Saldanha Bay constitutes a reserve of ±3500 million Mt of apatite and the deposit on the Agulhas Bank comprises 5500 million Mt. The phosphate deposit off Saldanha Bay occurs as an extensive, low to medium grade deposit. Although vast resources of potash and phosphatic minerals occur along the southern African outer continental shelf the expensive nature of marine exploitation may render most of these deposits, especially the phosphates, subeconomic. The low price of fertilizer andextensive natureontheonland deposits, although confined to asmallnumber of countries, mean that it will not be financially viable to extract these deposits. Assuming high grade glauconitic sand with the right composition can be located, the high market price indicates good future prospects for these potash deposits.  相似文献   
8.
丁贤荣  张鹰 《海洋科学》2003,27(2):8-12
在1981、1991(1990)和1998年3次海洋环境调查的基础上,通过相同水质要素时空比较分析,江苏海域的溶解氧、磷酸盐、硝酸盐和亚硝酸 盐这4种主要海水化学因子具有时空变化特征,其高值区主要分布在灌河口、扁担港口、射阳河口、川东港和长江北支口北侧,且河口、近岸值高,向海含量渐小,不同年份、季节也有变化。沿海水化学性质主要受陆源排污(农田化肥等)影响,主要是入海河流携带污染物、海洋生物作用和本海域水体运动特征的影响,此外,溶解氧变化还受到水温变化的影响。  相似文献   
9.
二色桌片参酶解液对转化细胞的效应   总被引:3,自引:2,他引:3  
陈正明  陈玉强  曹顺达  吴乔  苏文金 《台湾海峡》1997,16(3):270-274,T001
用二色桌片参(Mensamariaintercedens)酶解液处理转化的人胚肺成纤维细胞(NLF)后,细胞生长受到显著抑制,抑制率达64.84%,光镜下细胞透光性加强,铺展较好,细胞核形更为规则,核畸形现象减少;线粒体结构趋于正常;软琼脂集落实验表明,细胞集落形成率由23x10-5下降至12.5x10-5,裸小鼠致瘤实验显示抑瘤率为82.39%,差异显著(p<5%)。结果提示,二色桌片参酶解液可能逆转转化的HLF细胞的恶性表型,对其有一定的诱导分化作用。  相似文献   
10.
A limnogeological reconnaissance study was carried out on Lake Iznik, located in the southeast of the Marmara region of Turkey, involving a seismic survey and collection of short sediment cores. This lake is located on the middle branch of the North Anatolian Fault Zone (NAFZ), a transform plate boundary between the Eurasian and Anatolian Plates. It is, therefore, tectonically active and offers an opportunity to investigate the interplay of sedimentary and seismo-tectonic processes, as well as climate change and human impact in the region. Short cores of the three sub-basins, maximum length of 35.5 cm, recovered non-laminated, blackish clays and silts with varying amounts of biogenic and minerogenic (allochthonous, autochthonous) material, which documented almost the last 80 years of deposition and environmental history. High sedimentation rates in the deeper core sections are accompanied by changes in land use (conversion of woodland to farmland) in the northern areas of Lake Iznik, which caused the deposition of more weathered material (high K/Na ratios) and higher contents of Mn in the lake. A tendency towards eutrophic conditions within the last 20 years is indicated by high nutrient content (N, TOC, P), decreasing C/N-ratios, and characteristic diatom and cladoceran associations. Also increased pollution is revealed by higher Pb, Cu, and Zn contents and increased supply of human and animal faeces (high coprostanol content) during the last two decades. But simultaneous lower sedimentation rates towards the core tops complicate the reconstruction of recent and past eutrophication and pollution states of Lake Iznik. This requires an extension of the pilot study and deeper sediment cores, to recover non-anthropogenic influenced sediment levels.  相似文献   
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