SOCIAL RELATIONS SPATIALLY FIXED: CONSTRUCTION AND MAINTENANCE OF SCHOOL DISTRICTS IN SAN ANTONIO,TEXAS

ABSTRACT. More than 140 court cases filed in the United States between 1970 and 2003 argued that unacceptable and unconstitutional funding disparities exist among school districts in most states. In those arguments, stories, statistics, and maps are used to compare various school districts to prove that conditions are indeed unequal. Both sides—plaintiff and defendant—use such information to disprove each other's contentions. In so doing, each assumes that the political spaces of the school districts are absolute, timeless, and independent. Failure to recognize that these spaces—the school districts—are not objective but, in fact, constitutive of the class and race relations actually being argued and debated in court further legitimates local geographies of privilege and deprivation. I examine the formation of the school districts around San Antonio, Texas to illustrate that these districts are far from independent of one another and were formed to isolate privileged communities from the rest of the city. A relational view of space‐time allows such spaces as school districts to assume a political role, as opposed to the absolute, independent spaces they now represent.     

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.     

The Ambiguous Roles of Suburbanization and Immigration in Ethnic Segregation: the Case of San Antonio1

The traditional spatial assimilation model, though still operative, has proven inadequate to explain new trends in urban residential location in which, for example, disadvantaged and newly arrived groups move directly to the suburbs where they may re-segregate rather than disperse. Understanding residential patterns after 1990 often benefits from a micro-level approach, looking at specific cities and disaggregating traditional measures (e.g., the dissimilarity index) to examine changes within areas and neighborhoods of the city. This study takes such an approach. It analyzes segregation by means of the residential micro-patterns that give rise to it, and examines their relationship to suburbanization and immigration in greater San Antonio (Bexar County) during the 1990s for four ethnic groups: Hispanics, Blacks, non-Hispanic Whites, and Latino immigrants. The results reveal that segregation patterns in San Antonio have deep historic roots—the result of ongoing processes of urban job and housing availability, minority political power, and economic mobility. They show that the dissimilarity index declined for all groups in the 1990s, a decline chiefly attributable to deconcentration (lessening overrepresentation) in the inner city. By contrast, in the outer suburban city, incursion (moving into new areas) was offset by hyper-concentration (concentrating with fellow ethnics) such that the dissimilarity index neither increased nor declined. A typology is developed to explain the different pathways by which the dissimilarity index may increase or decrease in a metropolis. Finally, the results show that Latino immigration increased the overall dissimilarity index for Hispanics as well as for other groups in San Antonio.     

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.     

A three-step floating catchment area method for analyzing spatial access to health services

Gravity-based spatial access models have been widely used to estimate spatial access to healthcare services in an attempt to capture the interaction of various factors. However, these models are inadequate in informing health resource allocation work due to their inappropriate assumption of healthcare demand. For the purpose of effective healthcare resource planning, this article proposes a three-step floating catchment area (3SFCA) method to minimize the healthcare-demand overestimation problem. Specifically, a spatial impedance-based competition scheme is incorporated into the enhanced two-step floating catchment area (E2SFCA) method to account for a reasonable model of healthcare supply and demand. A case study of spatial access to primary care physicians along the Austin–San Antonio corridor area in central Texas showed that the proposed method effectively minimizes the overestimation of healthcare demand and reflects a more balanced geographic pattern of spatial access than E2SFCA. In addition, by using an adjusted spatial access index, the 3SFCA method indicates strong potential for identifying health professional shortage areas. The study concludes that 3SFCA is a promising method to provide health professionals and decision makers with useful healthcare accessibility information.     

Modeling River Connectivity Using the Barrier Assessment Tool and Available Data on Registered Dams in the Guadalupe–San Antonio River System,Texas

The rate of dam building has declined in the United States, but dam building is still considered an integral part of water supply management, particularly in arid and semiarid regions. Understanding how dams affect river connectivity is a key component of river basin management. This study analyzed the spatial and temporal patterns of fragmentation in the Guadalupe–San Antonio River System (GSARS) and how these patterns were related to dam size, age, and purpose. Using a shapefile of registered dams and the National Hydrography Dataset High Resolution (NHD-HR) as input data for the Barrier Assessment Tool (BAT), six successive connectivity models were created. The average length of functional river networks (FRNs) decreased over time but the number of FRNs over 100?km stayed relatively stable. Fragmentation in the GSARS was concentrated around urban centers, and the majority of fragmentation occurred gradually as dams separated small FRNs along tributaries and headwaters. This gradual decline in longitudinal connectivity was punctuated by sporadically large separations of river networks by particular dams based on their location and time of commissioning. The methodology presented here provides a way to analyze both the extent and the temporal evolution of fragmentation in a river system. Key Words: Barrier Assessment Tool (BAT), fragmentation, functional river networks, river connectivity.     

基于地理探测器的中国城市男性青少年BMI影响因子探究

运用变异系数与地理探测器方法分析中国城市男性青少年体质指数（BMI值）在2005年、2010年、2014年变化的空间分异,探究其核心影响因子。结果显示：① 中国城市男性青少年BMI值在东中西部存在显著性差异,变异系数分别为5.14%、1.68%、2.82%;区域内部也差异明显,东部差异性最强、中部最小。② 2005年中国城市男性青少年BMI值从东北向西南呈现由高到低的阶状分布特征,经9年的演变,2014年呈现出北高南低的三级阶梯分布特征。③ 中国城市男性青少年BMI增长率由2005—2010年的1.36%到2010—2014年的2.44%,说明中国城市男性青少年肥胖率呈加速上升趋势。④ 在空间尺度上,各区域探测的主导因素存在差异性。⑤ 在时间尺度上,从2005年到2010年,再到2014年,影响中国城市男性青少年BMI的主导因子由地理环境要素转为社会经济要素。     

20世纪90年代中国城市发展空间差异变动分析

城市化速度加快,城市区域化和区域城市化以及城镇体系开放性增强等是20世纪90年代中国城市发展的总体特征。以省级行政区为基本空间单元,选取25项城市发展指标, 利用SPSS统计分析软件对1990年和2000年中国城市发展进行主成份分析和聚类分析,得出20世纪90年代中国城市发展空间差异的变动特征是：① 城市发展水平的东西空间差异增大,东部沿海地区城市发展重心南移;② 城市发展速度东部沿海地区快于中西部地区,东部地区的南部大于北部,基础较好的城市集群发展速度较快;③ 东部沿海地区的北京和上海集聚性、外向性和创新性特点都很显著,中西部地区城市发展特征结构仍处于低水平均衡状态。国家目标、战略和政策的作用及其效果累积,城市发展动力机制和地理区位条件的差异是这一时期中国城市发展空间差异变动的主要原因。     

广州市家庭收入与住房特征对应关系的区位差异性

以广州市中心区(天河区)和郊区(南沙区)为研究案例,依托2010年中国(广东)家庭动态跟踪调查数据,基于家庭户住房的邻里特征、建筑特征、区位特征、家庭收入等13个指标构建路径分析模型,研究广州市居民家庭收入与住房特征的映射关系和影响方向。在此基础上,采用多群组路径分析方法研究区位因素对“收入→住房特征”的影响程度及其差异性。最后利用方差方程和均值方程,分析不同区位条件下(中心区和郊区)的住房特征差异。结果表明：① 家庭收入更显著地决定住房特征,对邻里特征的影响并不显著;② 区位对“收入→住房邻里特征”的关系具有显著调节作用,而对“收入→住房建筑特征”的调节作用较弱;③ 在中心城区和郊区的内部,家庭收入更显著地影响住房建筑特征,而对邻里特征基本无显著影响;④ 郊区家庭收入对公共交通时间便利性、住房面积、厕所设施水平、拥有住房数量、住房综合条件等几个主要住房特征指标的影响程度大于中心城区;⑤ 中心城区住房的邻里特征明显优于郊区,但建筑特征明显差于郊区。显示出广州市住房邻里特征与建筑特征在不同区位条件下的“互换特征”。     

重庆市新型城镇化质量与生态环境承载力耦合分析

本文以重庆市为研究对象,采用耦合分析法,通过分析新型城镇化质量和生态环境承载力主要指标,构建新型城镇化质量与生态环境承载力耦合协调模型,计算2000-2012年重庆市及各区县新型城镇化质量与生态环境承载力的耦合度,评价重庆市新型城镇化质量和生态环境承载力耦合阶段及水平,分析生态环境承载力与新型城镇化发展质量的耦合分类,为探索可持续发展的城镇化道路提供数据参考。结果显示：2000-2012年,① 重庆全市耦合度处于在0.967~1.000之间,显示出重庆市的新型城镇化质量与生态环境承载力的耦合阶段处在高水平耦合时期;② 重庆市区县新型城镇化质量与生态环境承载力耦合度分布基本符合“一圈两翼”的空间分异规律,耦合度范围在0.884~1.000之间,也处于生态环境与城镇化质量高耦合时期;③ 但重庆市各区县新型城镇化质量与生态环境承载力存在明显区域差异,尤其是生态环境承载力指数的空间差异比较明显,根据耦合状况可以大致分为4种区县耦合类型。表明重庆市快速城镇化的后果导致都市区生态压力增大,生态承载力空间差异显著的现实将导致原有城镇化发展方式面临不可维系局面,亟需调整城镇化发展方式;发展新型城镇化应通过优化资源利用方式,调整产业空间布局和升级产业达到疏导人口分布和提升城镇化发展质量的目的,最终缓解生态环境因城镇化快速发展带来的压力。     

基于DEA-ESDA的农业生态效率评价及时空分异研究

采用考虑非期望产出的SBM(Slack-Based Measure)模型,结合探索性空间数据分析方法（ESDA）,对甘肃省各县（区）2000~2014年的农业生态效率及空间分布格局进行实证分析。结果表明：① 考虑非期望产出和不考虑非期望产出的农业生态效率之间存在着明显差异,而考虑非期望产出的农业生态效率结果更符合实际情况。② 在研究期内甘肃省农业生态效率呈持续上升态势,但整体效率偏低;空间变化趋势呈现自西向东、自南向北递减态势,但南北差异小于东西差异。③ 从全局空间分异来看,除2001~2003年外,甘肃省各县（区）农业生态效率呈现正相关特征,空间集聚现象显著;从局部空间分异来看,处于空间正相关地区数量在研究期内逐渐下降,区域农业生态效率的集聚现象减弱。农业生态效率高高（HH）集聚主要分布在河西走廊及甘南地区,空间上具有明显的向邻接地区扩散的趋势;低低（LL）集聚主要分布在甘肃省中部地区,空间分布较为稳定。     

An approach for estimating vaccination coverage for communities using school-level data and population mobility information

Childhood vaccination data are made available at a school level in some U.S. states. These data can be geocoded and may be considered as having a high spatial resolution. However, a school only represents the destination location for the set of students who actually reside and interact within some larger areal region, creating a spatial mismatch. Public school districts are often used to represent these regions, but fail to account for private schools and school of choice programs. We offer a new approach for estimating childhood vaccination coverage rates at a community level by integrating school level data with population commuting information. The resulting mobility-adjusted vaccine coverage estimates resolve the spatial mismatch problem and are more aligned with the geographic scale at which public health policies are implemented. We illustrate the utility of our approach using a case study on diphtheria, tetanus, and pertussis (DTP) vaccination coverage for kindergarten students in California. The modeled community-level DTP coverage estimates yield a statewide coverage of 92.37%, which is highly similar to the 92.44% coverage rate calculated from the original school-level data.     

北京环城游憩带旅游地类型与空间结构特征

本文针对我国城市居民以城市周边为目的地近距离旅游日益增长的现象 ,以北京市行政区域内除东城、西城、崇文、宣武四个城区以外 14个区县中的 2 35处旅游地作为研究样本 ,按照地复合分类法根据旅游地的资源属性和旅游活动的性质将旅游地分为 9种类型 ,根据北京市情况可归并为 4类 ;运用空间结构、计量地理学理论以及地理信息系统、电话调查等技术手段 ,将四类 2 35处旅游地的大量数据分别进行了城市中心距离、回转半径法、空间分布曲线、空间离散指数等旅游计量地理研究 ,从而得出北京环城游憩带旅游地的空间结构特征     

中国省际资源环境成本及生态负荷强度的时空演变分析

为了科学地评价区域生态系统对经济与社会发展的服务支撑能力,引入生态系统服务理论等构建资源环境成本及绿色GDP核算、生态负荷强度模型,计算出中国31个省区2001~2012年的资源环境成本、生态负荷强度,在此基础上利用探索性空间数据分析方法对2001年以来中国省区的生态负荷强度随时间演变的趋势及其空间分布特征进行分析和探讨（港澳台除外）。结果表明,在研究时段内中国省区的资源环境成本由16.83×10¹²元攀升到25.24×10¹²元（2001年可比价）,生态负荷强度由1.55下降到0.45;中国生态负荷强度呈西北、东部沿海地区集聚的空间分布特征,其中西北为高-高、东部沿海为低-低集聚区;这种西、东集聚现象的显著性在研究时段内逐渐减弱,空间负相关区域增加到11个、具有持续扩张的趋势,区域生态效益或经济效益持续向周边溢出。     

Management implications of spatiotemporal non-stationarity in municipal water consumption patterns and drivers

This study analyzed the individual and joint influences of social, urban, and physical drivers on patterns of county-scale municipal water consumption (MWC) the for the state of Texas using a cross-sectional research design on three distinct temporal slices (1990, 2000, and 2010). Global multiple linear regression models and measures of global and local spatial association were combined to determine which drivers significantly influenced county-scale per capita MWC, whether or not the statistically significant drivers varied over time, and to assess the degree to which the patterns and drivers of MWC exhibited spatial stationarity. Overall results suggested the social, urbanized, and physical environments contributed significantly to the patterns of per capita MWC to varying degrees in each year. The social and urbanized environments consistently exerted the strongest influences on per capita MWC, while the physical environment was generally less important. The social environment had the greatest cumulative influence in all three years, and the urbanized environment singly accounted for the majority of the variation in per capita MWC when the joint influences of the other significant drivers were considered. Spatial analysis of MWC patterns and drivers suggested that they both exhibited weak to moderate degrees of spatial non-stationarity in each year, as well as that MWC patterns and drivers may be sensitive to regional and climatic boundaries. Identification of temporally consistent MWC drivers merged with longitudinal and cross-sectional research designs can improve water management strategies by offering managers greater insight into the relationships between landscape change and water consumption patterns.     

Multilevel built environment features and individual odds of overweight and obesity in Utah

Based on the data from the Behavioral Risk Factor Surveillance System (BRFSS) in 2007, 2009 and 2011 in Utah, this research uses multilevel modeling (MLM) to examine the associations between neighborhood built environments and individual odds of overweight and obesity after controlling for individual risk factors. The BRFSS data include information on 21,961 individuals geocoded to zip code areas. Individual variables include BMI (body mass index) and socio-demographic attributes such as age, gender, race, marital status, education attainment, employment status, and whether an individual smokes. Neighborhood built environment factors measured at both zip code and county levels include street connectivity, walk score, distance to parks, and food environment. Two additional neighborhood variables, namely the poverty rate and urbanicity, are also included as control variables. MLM results show that at the zip code level, poverty rate and distance to parks are significant and negative covariates of the odds of overweight and obesity; and at the county level, food environment is the sole significant factor with stronger fast food presence linked to higher odds of overweight and obesity. These findings suggest that obesity risk factors lie in multiple neighborhood levels and built environment features need to be defined at a neighborhood size relevant to residents' activity space.     

The spatial extent and coverage of tornado sirens in San Marcos,Texas

The tornado siren has become the standard method of notifying resident populations of dangerous weather conditions. In March, 2012, the city of San Marcos, Texas purchased 14 Tempest-121 rotating sirens creating a coverage network. Because San Marcos has experienced two tornadoes during the previous twelve years, two research questions were constructed, 1) what is the spatial coverage of the tornado siren network in San Marcos, and 2) what is the approximate number of residents located outside the siren's network coverage area? The hypothesis stated that the siren network left more than 10 percent of the population outside the coverage area.Each tornado siren was individually located and associated GPS data allowed for construction of the siren network in a GIS. The analysis identified approximately 26 percent (22 km²) of San Marcos located outside the network's coverage area. Furthermore, analysis of census block data and the extent of siren coverage resulted in 5.14 percent of residents not included in siren coverage, approximately half compared to what was hypothesized. As San Marcos continues to expand, both in size and in population, the question of whether there is enough coverage for the entire city for the foreseeable future remains unclear.     

基于手机信令数据的广西区域多尺度网络空间结构研究

为揭示广西壮族自治区网络空间结构特征,采用手机信令数据分别从亚区域、地级市、市区―市区、市区―县（市）和县（市）―县（市）5个尺度测度了其网络关联强度和中心性。结果表明：1）在水平联系上,亚区中桂南中心性最高,其次是桂西和桂北,桂东中心性最低;4个亚区间的联系表现为桂南与桂西间联系最密切,桂南与桂东、桂北间的联系相对较强,桂北与桂东、桂西间的联系相对较弱,桂西与桂东间联系最弱。地级市间南宁中心性最高,其次是来宾;关联网络以南宁为核心向外辐射,有2条突出的联系,分别为南宁―河池和南宁―来宾。市区联系网络中,桂林市区的中心性最高,其次是柳州市区和玉林市区,河池市区中心性最低;有5条联系较为突出,分别为防城港―钦州、贵港―来宾、钦州―南宁、来宾―柳州、崇左―南宁。县（市）之间的关联强度总体水平较低,关联强度较高的联系主要分布在北部湾城市群、西江经济带、324国道沿线以及桂林漓江风景区周边。2）在垂直联系上,亚区内部城市间联系表现为桂北最强,桂东、桂南其次,桂西最弱。受行政管辖的影响,市区与县（市）间的联系符合一般的距离衰减规律,部分市区和与县（市）之间的联系超出行政管辖的范围;基于各市区的腹地与行政辖区的对比,发现南宁、柳州为跨界市区―县（市）格局,河池为弱界市区―县（市）格局,其余的为适界市区―县（市）格局。     

Racial/ethnic,area socioeconomic,and geographic disparities of cervical cancer survival in Texas

A better understanding about the factors associated with cervical cancer survival disparities is an important step in developing more effective cervical cancer intervention strategies. This study investigates cervical cancer survival disparities from three different perspectives based on data from the Texas Cancer Registry from 1995 to 2005. These perspectives are race/ethnicity, area socioeconomic status (SES), and geographic locations. We examined the role of both individual- and contextual-level factors in cervical cancer survival disparities using a multilevel survival analysis. Individual-level factors included race/ethnicity, age at diagnosis, year of diagnosis, tumor grade, stage at diagnosis, and type of treatment received. Contextual-level factors are census-tract-level variables, including demographic characteristics, health insurance expenditure, behavioral factors, extent of urbanization, and spatial access to primary care physicians. This study reveals that African-Americans had a higher mortality risk (HR, 1.19; 95% CI, 1.03–1.38) especially if stage was unknown (HR, 1.72; 95% CI, 1.08–2.75) compared with non-Hispanic whites. Among women diagnosed at regional or distant stage, Hispanics had a survival advantage over their non-Hispanic white counterparts (HR, 0.80; 95% CI, 0.69–0.94). We also identified geographic areas where longer-than-expected or shorter-than-expected cervical cancer survival was statistically significant. Only a small portion of these disparities were explained by individual- and contextual-level factors. This study suggests that Race/Ethnicity, SES, and geography are associated with cervical cancer survival in Texas.     

渭河流域水土流失治理效率的时空格局演化与影响因素

运用Bootstrap-DEA模型计算2000~2015年渭河流域陕西段39个县区水土流失治理效率;结合探索性空间分析方法（ESDA）和地理加权回归模型(GWR)分析各县水土流失治理效率的时空演化特征及其影响因素。研究结果表明：① 2000~2015年,研究区水土流失治理效率从0.263增至0.336,整体治理效率仍处较低水平;前期生态治理效率的增加缘于纯技术效率的提高,后期规模效率对治理效率的增加起到了主导作用。② 县域的治理效率在空间上呈现集聚状态;热点分析结果进一步显示,2005年治理效率表现出2个热点集聚区,即以宝鸡市千阳县为热点区、乾县和武功县为核心辐射至永寿县和礼泉县的热点集聚区,冷点区域则以临潼为中心,辐射到西安市辖区、高陵、富平和三原县;2010~2015年治理效率的热点区域与冷点区域较2005年有所收缩且保持相对稳定。③ 渭河流域水土流失治理效率的时空变化是降水、坡度、灌草面积覆盖度、人口经济和农业生产共同作用的结果,且各影响因素在不同时期对各县的治理效率的贡献呈动态变化,这意味着政策制定者需要从全局角度权衡不同因素的影响效果。