资源问题的历史、现状和未来

概述 1.老问题和新问题对资源问题早有争议并引起完全相反的见解。历史上曾有过二次,一次是18世纪末,另一次是19世纪下半叶。当时,经济学家、自然主义者、哲学家、地理学家和政治领导人开始关心经济活动的最终目的以及中、长期前景。一些人认识到人口的持续增长及食品和工业产品消耗的扩大都可能引起危机。     

安泰—斯特列措夫铀矿床上近矿交代的垂直分带性

本文详细地研究了俄罗斯最大的铀矿床安泰－斯特列措夫矿床近矿热液交代的垂直分带性及不同深度水平上的地球化学组构特点。     

APPLICATION OF THE TRRL FLOOD ESTIMATION MODEL IN HYDROLOGICAL FORECASTING FOR CATCHMENTS WITH LIMITED DATA A CASE STUDY

１ＩＮＴＲＯＤＵＣＴＩＯＮＯｎｔｈｅｍｏｒｎｉｎｇｏｆ３０ｔｈＪａｎｕａｒｙ１９９２,ａＮａｉｒｏｂｉｂｏｕｎｄｐａｓｅｎｇｅｒｔｒａｉｎｆｒｏｍＭｏｍｂａｓａｏｎｔｈｅｍａｉｎｌｉｎｅｄｅｒａｉｌｅｄｉｎｔｏａｎｅｍｂａｎｋｍｅｎｔｔｈａｔｈａｄｂ...     

Urban growth in South Asia

The author discusses urbanization in Southern Asia during the period 1950-1980 using U.N. estimates. Urbanization in the region as a whole is compared with trends in other developing regions, and differences among the experiences of seven countries of Southern Asia are examined. Tabular information is provided on urbanization levels and urban population growth rates for Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, and Sri Lanka.     

Numerical simulation of organic chemicals in a marine environment using a coupled 3D hydrodynamic and ecotoxicological model

For ecotoxicological risk assessment in a marine ecosystem, we constructed a coupled three-dimensional hydrodynamic and ecotoxicological model (EMT-3D), and applied it to Tokyo Bay. The model was calibrated with field data obtained in 2002. The results of sensitivity analysis for dissolved Bisphenol A showed that biodegradation rate was the most important factor for concentration change. Bioconcentration coefficient was the most important factor for Bisphenol A in phytoplankton. Therefore, the parameters must be carefully considered in the modeling. The mass balance results showed that standing stocks of Bisphenol A in water, in particulate organic carbon and in phytoplankton are 7.85 x 10(4), 1.78 x 10(2) and 3.44 x 10(-1) g, respectively. With respect to flux, biodegradation in the water column had the highest value of 1.06 x 10(3) g/day, and next were effluent to the open sea, partition to particulate organic carbon, and bioconcentration in phytoplankton.     

太平洋西部中国沿岸海平面的变化

在有关世界大陆架地形和沉积的许多著作中,已对更新世冰期的低海平面作过研究。目前的残留海岸沉积和化石深度表明,冰川消溶前的海平面可能比现代低150米。海平面上升的大约深度和年代,是根据对残留的或准化石的海岸贝壳,和对从大陆架挖取或钻     

O,p'-DDT induction of vitellogenesis and its inhibition by tamoxifen in Nile tilapia (Oreochromis niloticus)

In order to investigate the mechanism by which o,p'-DDT disrupts endocrine functioning of Nile tilapia in vivo, the estrogenicity of o,p'-DDT was investigated in conjunction with 17beta-estradiol (E2) and tamoxifen. Mature, male tilapia were treated intraperitoneally with o,p'-DDT (60 mg/kg, one dose) or E2 (5 mg/kg, four doses) in the presence or absence of tamoxifen (5 mg/kg, six doses) for 12 days and then plasma vitellogenin (Vtg) (measured as alkaline-labile phosphorous), E2, and testosterone (T) were measured. Vtg levels were increased dramatically by E2 (1,744 +/- 171 microg/ml) and moderately by o,p'-DDT (82 +/- 15 microg/ml) compared with controls (23 +/- 3.5 microg/ml). Tamoxifen alone had no effect on Vtg production, but inhibited both E2 and o,p'-DDT stimulated vitellogenesis. T levels were reduced with E2 administration (1,688 +/- 383 pg/ml) and declined further with the combined treatment of E2 and tamoxifen (281 +/- 70 pg/ml), compared with controls (6,558 +/- 1,438 pg/ml). Tamoxifen or o,p'-DDT alone did not affect T levels, but their combined treatment did (2,069 +/- 647 pg/ml). The results of this study suggest that o,p'-DDT is weakly estrogenic in male tilapia, and that this activity may be mediated through the estrogen receptor.     

中印度洋强变形带内的洋底构造

由地震活动性、地球形状、重力异常和异常的热流反映出在赤道附近的中印度洋盆地内，沉积物和基底的强烈变形，显示出在长波长和短波长两方面的板内挤压岸石圈变形的明显证据．地震反射剖面显示，基底东西向线型波状起伏以及与地球形状不规则有关的基底高和低，     

三万五千年以来的海平面

美国大西洋陆架35,000年来的海平面曲线,是建立在80多个放射性碳年代的基础上,其中15个年代是老于15,000年代的。测年的材料包括浅水软体动物、鲕状岩、珊瑚藻、海滩岩和盐沼泥炭。30,000—35,000年前的海平面,曾经是接近于现在的海平面的。随后冰川发育,16,000年前海平面降低到负130米左右。全新世海侵可能开始于约14,000年前,并迅速地延续到约7,000年前。世界大多数大陆架的年代和这条曲线相一致,说明这条曲线大致是这个时期海平面升降的曲线。