Estimation of birthdates and catch-at-age using length frequency analysis (LFA), with application for skipjack tuna (Katsuwonus pelamis) caught in the Southwest Atlantic     

Andrade  Humber A.; Kinas  Paul G. 《ICES Journal of Marine Science》2004,61(5):798-811

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Coral Recruitment and Regeneration on a Maldivian Reef 21 Months after the Coral Bleaching Event of 1998     

Karen Loch  Wolfgang Loch  Helmut Schuhmacher  Wolf R. See 《Marine Ecology》2002,23(3):219-236

Abstract. This paper describes the quantitative inventory of stony corals on a Maldivian reef after the bleaching event of 1998. The detailed data, collected in March 1999 and March 2000, comprise survival, new recruitment and regenerates. They were obtained in 6 transects laid out randomly on the reef flat, on 22 Acropora tables on 6 sites at the reef edge and on 39 Porites lobata blocks and 1 Diploastrea heliopora colony. The present cover of living zooxanthellate corals is reduced to ca. 2 – 5 % of its previous state. Acroporidae and Pocilloporidae were practically wiped out, while Poritidae survived partly and Agariciidae (esp. Pavona) are now the dominant group. New settlements on dead Acropora tables were mainly Agariciidae, followed by Acroporidae and Pocilloporidae. Regenerates on Porites were pronounced and the apparent yearly increase in mass was about threefold that of Diploastrea, which is 3 – 4 mm per year. The influence on reef ecology in terms of coral substrate and species, possible sources of larvae, change of guilds in reef builders, other species and the prospect for further development of the reef, with respect to growth versus erosion, is discussed.  相似文献   

基于GIS空间统计分析的广电收视率评估研究——以北京市广电收视覆盖分析系统为例     

贠建明  雷兵  杨永崇 《测绘科学》2008,33(3):160-162

本文将GIS空间信息统计分析手段应用于广播电视收视率的评估,以层次分析法为基础进行改进,采用抽样调查的方法确定权重,提出较为合理的基于空间信息统计方法的广电人口覆盖分布模型并加以软件实现。以北京市为研究区域,经导入多个版本人口数据实验,发现这种评估方式较好地修正了传统的仅仅按照面积评估覆盖率的评估模型,对于提高广电行业的信息化管理水平具有一定意义。  相似文献   

CA-AR模型在人口空间场属性变化模拟中的应用     

代富强 《测绘科学》2008,(Z1)

本文结合CA(cellular automata)和AR(auto-regression)提出模拟人口空间场属性变化的CA-AR模型,以1991～2006年成都市各区、县市的人口统计数据和成都市行政区划图为基础,将行政单元转化为单元网格,分别建立成都市主城区各单元格的CA-AR模型。结果显示,模拟结果的绝对误差和相对误差都较小,模拟精度较高,模型的显著性水平都比较高,说明CA-AR模型用于模拟人口空间场的人口数量变化是可行的。  相似文献   

基于GIS的人口分布图的绘制研究——以辽阳市为例     

王雅雯  王利  郭峰 《测绘与空间地理信息》2008,31(2):97-101

主要论述传统的人口分布专题地图方法及其不足,阐述了人口分布与土地利用之间的关系,运用人口在不同用地类型上的分配的理论,模拟人口分布,根据辽阳市的土地利用情况以及人口数字准备来绘制人口分布图。  相似文献   

POPULATION EXPANSION IN CHINA''''S METROPOLISES AND ITS SCALE-CONTROL     

何兴刚 《中国地理科学(英文版)》1993,(3)

Metropolises are centers of politics, economy, culture and information, and also economic growth poles in comparatively large areas. After 1949, China's urban structure have changed greatly, from original "pyramid" shape into "upside -down pyramid" shape, that is, more megalopolises and metropolises, fewer medium-sized and small cities. The most distinguishing feature of urban population growth was the remarkable increase of population in megalopolises and metropolises. The key reason for urban population expansion is to want to obtain the benefits of scale -agglomeration economy of metropolises. The number of urban functions directly determines the quality and quantity of urban population. Metropolises appeal not only agricultural population but also the population of medium-sized and small cities, which put much more population pressure on metropolises. The ideal goals of scale-control of metropolitan population are discussed in terms of economy, society and ecollogy. In order to control the metropoli  相似文献   

Two methods of orthogonally stepwise discrimination and their applications     

Xueren Wang  Jin Zhang 《Mathematical Geology》1992,24(2):203-218

In this paper, we describe two methods of discrimination based on MSE ratio and regression, respectively, and an algorithm of orthogonally stepwise discrimination. The method is not limited by the assumption that the sample covariance matrix is not ill-conditioned or singular, and by any assumption about the distribution of each population as well. So, it has wide range of application to various problems, particularly, to the problem of discrimination with both quantitative and qualitative variables. After variables are selected in the procedure of stepwise discrimination, they need not be rejected. Several examples have been calculated by using the method, and the results are quite satisfying.  相似文献   

固始县农民工流动时空变化研究     

秦奋  李建忠 《地域研究与开发》2006,25(2):43-46

在实际调查数据基础上，文章分析了农民工流动的时空变化趋势和对流出地的影响。调查分析结果表明：固始县外出务工人数逐年递增；农民工以男性为主，但妇女所占比例在逐年提高；农民工务工收入逐年提高。农民工教育程度越高，收入也越多。农民工务工半径随时间逐渐扩大，基本扩展到全国所有省份，但农民工的收入省际变化不大。农民工不仅给流出地带来经济上的变化，而且对文化教育、社会结构和思想观念也有很大的影响。  相似文献   

流动人口分布与区域经济发展关系若干解释(1990、2000)   总被引：10，自引：1，他引：10  

鲁奇  王国霞  杨春悦  曾磊 《地理研究》2006,25(5):765-774

本文对我国1990、2000年间流动人口在东、中、西部和东部地区中环渤海、长江三角洲、珠江三角洲及福建三个亚区的分布变化以及这一分布变化与上述各地区各相关经济与非经济因素变化的关系进行了研究。研究发现,10年中流动人口东、中、西部分布变化与东、中、西部经济发展的变化高度一致;而10年中流动人口在东部地区环渤海、长江三角洲、珠江三角洲及福建这三个亚区层面的分布变化则与经济发展要素变化有一致的方面,也有不一致的方面。珠江三角洲及福建的经济增长带来了流动人口的大幅增长,除珠江三角洲劳动密集型企业众多外,这可能与该区域地方社会人文等文化本底所决定的经济发展制度及习俗有一定的相关性。  相似文献   

"泛珠三角"产业、人口分布空间变动的趋势分析   总被引：1，自引：2，他引：1  

李铁立  徐建华 《地理科学》2006,26(4):402-408

随着地区经济一体化的发展,“泛珠三角”区域的经济格地理局将会出现不同程度的变化。当前“泛珠三角”区域一体化处于中期发展阶段,主要表现为产业和人口向“珠三角”集中。今后随着一体化的进一步发展,产业和人口将具有集中与扩散同时发生的特征,各地区形成特定产业和人口集中的专门化生产的地理格局。  相似文献