Land use as a mitigation strategy for the water-quality impacts of global warming: a scenario analysis on two watersheds in the Ohio River Basin

This study uses an integrative approach to study the water-quality impacts of future global climate and land-use changes. In this study, changing land-use types was used as a mitigation strategy to reduce the adverse impacts of global climate change on water resources. The climate scenarios were based on projections made by the Intergovernmental Panel on Climate Change (IPCC) and the United Kingdom Hadley Centre's climate model (HadCM2). The Thornthwaite water-balance model was coupled with a land-use model (L-THIA) to investigate the hydrologic effects of future climate and land-use changes in the Ohio River Basin. The land-use model is based on the Soil Conservation Service's curve-number method. It uses the curve number, an index of land use and soil type, to calculate runoff volume and depth. The ArcView programming language, Avenue, was used to integrate the two models into a geographic information system (GIS). An output of the water-balance model, daily precipitation values adjusted for potential evapotranspiration, served as one of the inputs into the land-use model. Two watersheds were used in the present study: one containing the city of Cincinnati on the main stem of the Ohio River, and one containing the city of Columbus on a tributary of the Ohio River. These cities represent two major metropolitan areas in the Ohio River Basin with different land uses experiencing different rates of population growth. The projected hypothetical land-use changes were based on linear extrapolations of current population data. Results of the analyses indicate that conversion from agricultural land use to low-density residential land use may decrease the amount of surface runoff. The land-use practices which generate the least amount of runoff are forest, low-density residential, and agriculture; whereas high-density residential and commercial land-use types produce the highest runoff. The hydrologic soil type present was also an important factor in determining the amount of runoff and non-point-source pollution. A runoff-depth matrix and total nitrogen matrix were created for Cincinnati and Columbus to describe possible land-use mitigation measures in response to global climate change. The differences in Cincinnati and Columbus were due to differences in geographic location, air temperature, and total runoff. The results of this study may be useful to planners and policy makers for defining the possible impacts of future global climate and land-use changes on water resources.     

以监测预报工作为导向推进数字化监测教学

地震预测的发展方向,是从协同的观点,多层面地统筹考虑地震监测体系的建设,实现基础研究与实际地震预测工作的结合.本文从如何利用原有监测资料、连续前兆监测数据处理系统的建立、前兆监测体系数据报送体系等地震监测工作环节,分析地震监测教学如何与监测工作方向相一致,并对教学改革如何结合台站技术人员更新提出了几点看法.     

Experimentally proved biosynthesis of vitamin C in a guinea pig

The Science of Nature -     

后扣板冷挤压工艺及模具

此文分析了产品成形的特点,模具承载的负荷特点,从而在成形工艺上、润滑上、模具结构及选材上采取了相应的措施.用H-4水基高分子润滑剂和3Cr2W8V制作冷挤压模都取得了明显效果.     

新加坡控制汽车排放污染的经验

汽车，作为现代文明的产物一经出现便得到了迅猛的发展，给世界带来了动感，给人们的生活带来了便捷和舒适，但与此同时也给我们赖以生存的环境带来了越来越严重的空气污染。资料表明，发达国家城市空气污染中曾经主要来源于汽车的排放，在汽车密度大的国家和地区，汽车排放污染成为严重的社会公害，有些国家还发生了光化学污染事件，     

兰州西固地区光化学烟雾污染气质模式

以兰州西固地区为研究对象,建立了描述该地区光化学烟雾污染的大气质量模拟模式——柱子模式。将该模式与实测数据进行了比较,结果表明,该模式基本上能够定量地描述当地所发生的光化学烟雾污染的主要污染物的时空分布及形成过程,可为污染评价、预测及污染治理提供依据。     

碱性条件下化学法处理大同齿轮厂混合电镀废水

针对大同齿轮厂电镀车间外排废水中既含CN- 离子 ,又含Cr6+及Ni2 +、Zn2 +、Cu2 +等重金属离子的现状 ,在碱性条件下 ,采用先氧化破氰 ,再还原六价铬至三价铬 ,最后混凝沉淀的处理工艺 ,使处理后出水达标排放     

Limb reduction and chorion villus sampling

Upper limb reduction was diagnosed by ultrasound scan at 17 weeks after chorion villus sampling at 9 weeks' gestation. Pregnancy was terminated and necropsy confirmed limb reduction in an otherwise normal fetus. The relationship of limb reduction to amniotic band syndrome is discussed.     

Predator odour and its impact on male fertility and reproduction in Phodopus campbelli hamsters

 This study investigated the influence of cat urine odour in suppressing development and fertility in Campbell's hamster males. Exposure to this odour from postnatal day 11 until day 45 (sexual maturation) resulted in reduced sex organ weights, reduced testosterone levels and in an increase in abnormalities of the synaptonemal complex in both sex chromosomes and autosomes. Subsequent breeding experiments revealed a significant decrease in litter size. All these data indicate a severe effect of predator odour on the breeding success of potential prey species. It is assumed that these effects are caused by the sulphurous compounds in the urine; however, the underlying mechanisms are not yet known. Received: 31 January 2000 / Accepted in revised form: 6 June 2000     

Gold mining in Siberia and the Far East as a source of mercury contamination of the environment

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