Trade Competition and Route Development in Georgia and the Carolinas, 1740-1900

Abstract

The “ideal-typical” sequence model of transportation development has been widely referenced, but its application outside of its original African context has not been well tested. A graphical analysis is employed to evaluate the utility of the concept in explanation of the evolution of the transportation network in the Piedmont and Coastal Plain sections of Georgia and the Carolinas from the mid-eighteenth century to the late nineteenth century. The historical geography of transport expansion in this area appears to support the general parameters of the ideal-typical sequence and provides useful material for instruction related to the national standards for geographic education.     

Labor Market Marginalization of Youth in San Antonio,Texas

Poverty among inner‐city residents is associated with their marginal status in the labor market. Marginalization in the labor market begins during youth when important educational and employment decisions are made. Analysis of 1990 U.S. Census tract data for San Antonio, Texas identifies the lack of a high school diploma, poverty, non‐employment, and non‐enrollment in school as conditions of marginality for youth. Spatial patterns of youth labor market marginalization show concentrations in the inner city and in sectors on the West, South, and Eastside. Regression analysis reveals that levels of youth marginalization are associated with neighborhood context represented by the employment, behavioral, and ethnic characteristics of the overall residential population of a census tract.     

Labor Market Marginalization of Youth in San Antonio,Texas

Poverty among inner-city residents is associated with their marginal status in the labor market. Marginalization in the labor market begins during youth when important educational and employment decisions are made. Analysis of 1990 U.S. Census tract data for San Antonio, Texas identifies the lack of a high school diploma, poverty, non-employment, and non-enrollment in school as conditions of marginality for youth. Spatial patterns of youth labor market marginalization show concentrations in the inner city and in sectors on the West, South, and Eastside. Regression analysis reveals that levels of youth marginalization are associated with neighborhood context represented by the employment, behavioral, and ethnic characteristics of the overall residential population of a census tract.     

中国互联网产业发展的区域差异及其动态演进——基于生产和消费的视角

进入21世纪以来,中国的互联网事业飞速发展。无论是网民规模还是网站数量,都有了较大幅度的增长。本文基于互联网产业的生产与消费两个方面,利用锡尔系数和集中化指数等方法,对2000年至2009年中国(不包括港澳台地区)31个省(市、区)的互联网产业发展状况进行了一系列研究。结果发现:中国互联网产业发展的区域差异仍然十分显著,但消费层面的省际差异明显小于生产层面,而且消费层面差异缩小的幅度也明显大于生产层面。同时,从空间来看,东部地区的变化显著,大部分省市有了较大发展,但中西部地区的大部分省份仍处于低消费一低生产的状况。     

沼泽湿地对污水中NH4+-N和PO3-4-P净化模拟研究

选取三江平原典型沼泽湿地--毛苔草沼泽,通过人工施加氮肥和磷肥来模拟农田污水排入沼泽湿地后,沼泽植物对污水的净化效果.从植物营养吸收角度进行野外实地污水净化模拟研究,对植物直接吸收利用的营养成分NH4+-N、PO34--P进行了测试分析.研究表明毛苔草沼泽对水中的NH4+-N、PO34--P的净化随时间的推移呈现明显的指数衰减下降趋势,随着氮、磷含量的增加,沼泽湿地对污水净化逐渐变慢,净化所需时间增长,曲线数值方程模拟效果较好.     

沼泽湿地对污水中NH4^＋-N和PO4^3——P净化模拟研究

选取三江平原典型沼泽湿地———毛苔草沼泽,通过人工施加氮肥和磷肥来模拟农田污水排入沼泽湿地后,沼泽植物对污水的净化效果。从植物营养吸收角度进行野外实地污水净化模拟研究,对植物直接吸收利用的营养成分NH 4-N、PO3-4-P进行了测试分析。研究表明毛苔草沼泽对水中的NH 4-N、PO3-4-P的净化随时间的推移呈现明显的指数衰减下降趋势,随着氮、磷含量的增加,沼泽湿地对污水净化逐渐变慢,净化所需时间增长,曲线数值方程模拟效果较好。     

中国东南沿海区域经济差异及经济增长因素分析

采用东南沿海地区市55 个地区市的1995-2005 年间的经济综合发展水平数据, 对东南 沿海地区总体、局部的空间差异变化、空间格局的演化、特征及成因进行了初步探索。结果 表明: ① 1995-2005 年东南沿海地区经济发展水平差异时序分布和地区内部“极化”态势同 向, 表明东南沿海地区存在“两极分化”现象。② 东南沿海地区在1995-2003 年间地区经济 差异不断扩大, 这一时期, 三大地区内部经济差异水平分布层次不齐, 呈现南高北低的渐变 趋势, 表明这一阶段性的地区差异变动主要是由广东省、福建省内部差异构成; 2003 年以 来, 东南沿海地区经济差异呈现收缩趋势, 同时期, 三大地区经济差异均有收缩态势, 与东 南沿海地区整体差异变化趋势同向, 主要是由于长三角地区均衡发展驱动地区整体差异的缩 小; ③ 地区经济空间演化特征与地区经济差异时序波动吻合, 相应地在空间上呈现出“极 化→扩散”现象。