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W. Andrew Marcus 《Journal of Paleolimnology》1992,7(2):165-171
Conference AnnouncementsSpecialized Conference
Contaminated aquatic sediments: Historical records, environmental impact, and remediation, Milwaukee, USA, June 14–16, 1993 相似文献6.
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郝成元, 吴绍洪, 杨勤业 总被引：13，自引：8，他引：13
依据野外调查和遥感动态监测结果,对毛乌素地区的土地利用与沙漠化过程的发展及其防治进行了研究。结果表明,该地区20世纪80年代中期和90年代末轻度以上沙漠化土地面积分别占土地总面积的85.98%和86.07%,沙漠化土地的总面积略有增加,总体趋于稳定;但沙漠化程度加重,重度以上的沙漠化土地面积在总土地面积中增加了3.6%;沙漠化发展的重要原因之一就是人类不合理的土地利用方式。不合理土地利用方式及土地利用方式的改变,使以风沙活动为主导外营力的沙漠化过程得以发展。最后,根据毛乌素地区沙漠化过程与土地利用之关系,提出了研究区防治土地沙漠化应调整农业结构和土地利用方式的建议。 相似文献
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长期以来，由于忽视了人口、土地、粮食与灾害系统内各因素的相互协调，人类的生存与发展基本问题越来越多地摆在我们面前，致使在人口增长过快情况下，产生了土地资源质减量退，粮食生产徘徊不前，自然灾害频繁发生等危害生国计的社会问题，在跨入２１世纪的关键时期，如何采取有力措施解决上述问题，已为９０年代的重要任务，针对针中国国际本文分析了人口，土地，粮食，灾害相互间的关系，进而提出了相应之对策。 相似文献
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The Laboratory for Chemometrics at the University of Perugia is situated in the NaturalSciences Building,close to the centre of Perugia.Perugia is situated in Umbria,about 3 hoursnorth of Rome (by train).The old city centre is on a hilltop and has a well-preserved medievalcharacter,and also reminders from its Roman and Etruscan origin are abundant.Very closeto the Natural Sciences Building are the Via Appia and the Etruscan gate,and below the 相似文献
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长江三角洲,珠江三角洲,环渤海区域工业结构比较 总被引：10，自引：0，他引：10
从工业行业、规模、所有制、地域分布等方面对比分析环渤海、长江三角洲、珠江三角洲及其９省市工业结构的相似性和差异性,多角度研究三大区域九省市的工业结构特点,运用经济地理学和区域经济学理论,探索了上述区域分工与发展的方向。 相似文献
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《The Journal of geography》2012,111(4):466-470
Abstract Children love books, and through carefully chosen ones geographic concepts can be conveyed. Books are good resources—great background material for describing a place, emphasizing the culture of a region, highlighting a geographical issue, or clarifying where a place is in the world. This article explains how literature encourages geographic thinking, builds geographic skills, and develops lasting mental maps of places and regions. 相似文献
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Crime is both a factual and perceptual component of the urban landscape, seemingly both a societal pathology and the consequence of economic disparity between social groups. Crime has a spatial structure that can be revealed by mapping. Urban crime has a spatial multiplier effect that changes the values and perceptions of how people see urban space, and which jeopardizes the quality of life of a city's inhabitants. In this research we examine the question of whether the geography of actual criminal acts is echoed by peoples' perceptions of crime, what might be termed their “spaces of fear”. We ask how the fear of crime is associated with reported urban crime. Urban crime incidents have been increasing in Viçosa, Minas Gerais, Brazil. We assembled crime information about Viçosa from two sources: first, crime as reported to the police and second, crime as perceived by city residents and measured by surveys and interviews. Reported criminal acts reveal a clustered geography, focusing particularly on the Downtown area, where there is a concentration of urban wealth and potential victims are more numerous. Offenses against property were focused on Downtown, while offenses against the person were located mostly in peripheral areas. The widespread feeling of insecurity in the city's neighborhoods, reflecting the fear of becoming a victim of violence and crime, was common throughout the city. Results confirmed the conclusion of past studies showing that the fear of violence and crime are not directly related to increasing numbers of criminal reports. Sites with higher incidence of crimes are not places with higher levels of fear. Rather than being geographically explainable “spaces of fear”, the spatial distribution of the fear of violence and crime appears to be unrelated in Viçosa, and neither is clustered or dispersed in any measurable way. 相似文献
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FaradinaMerican WanMaznahWO WanAsmadiWA MashhorMansor 《湿地科学》2007,5(3):243-252
Researches on the Antarctic microalgal diversityand distributions in the freshwater environment ran-ging from snow to large lakes and well-definedstreams are extensive.For instance,studies on thestream microalgal community have been conducted onthe Pervay… 相似文献