首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
This study seeks to examine the relationship between childhood exposure to air pollution and long-term respiratory health and to identify significant predictors of respiratory health in adulthood. Logistic regression modeling was undertaken using health and exposure data for 395 participants who resided during childhood in four distinct neighborhoods in Hamilton, Ontario, Canada. Significant predictors include exposure to SO2 in childhood, location of residence in childhood, sex, residential and occupational histories, stressful life events, and respiratory health in childhood. This study suggests that the health impacts of childhood exposure to air pollution are located beyond the short-term period that most research addresses.  相似文献   

7.
8.
9.
10.
Books Reviewed:

Browning, Frank A Queer Geography: Journeys Toward a Sexual Self

Fellows, Will Farm Boys: Lives of Gay Men from the Rural Midwest

Rubenstein, James M. The Cultural Landscape: An Introduction to Human Geography. 6th ed

Knox, Paul L. and Marston, Sallie A. Human Geography: Places and Regions in Global Context

Kuby, Michael; Harner, John, and Gover, Patricia Human Geography in Action  相似文献   

11.
12.
Landing a rescue helicopter in a wilderness environment, such as Yosemite National Park, requires suitable areas that are flat, devoid of tree canopy, and not within close proximity to other hazards. The objective of this study was to identify helicopter landing areas that are most likely to exist based on available geographic data using two GIScience methods. The first approach produced an expert model that was derived from predefined feature constraints based on existing knowledge of helicopter landing area requirements (weighted overlay algorithm). The second model is derived using a machine learning technique (maximum entropy algorithm, Maxent) that derives feature constraints from existing presence-only points; that is, geographic one-class data. Both models yielded similar output and successfully classified test coordinates, but Maxent was more efficient and required no user-defined weighting that is typically subject to human bias or disagreement. The pros and cons of each approach are discussed and the comparison reveals important considerations for a variety of future land suitability studies, including ecological niche modeling. The conclusion is that the two approaches complement each other. Overall, we produced an effective geographic information system product to support the identification of suitable landing areas in emergent rescue situations. To our knowledge, this is the first GIScience study focused on estimating the location of landing zones for a search-and-rescue application.  相似文献   

13.
14.
15.
A relatively simple modeling approach for estimating spatially distributed surface energy fluxes was applied to two small watersheds, one in a semi-arid climate region and one in a sub-humid region. This approach utilized a combination of ground-based meteorological data and remotely sensed data to estimate ‘instantaneous’ surface energy fluxes at the time of the satellite or aircraft overpasses. The spatial resolution in the watershed grid cells, which was on the order of 100-400 km, was selected to be compatible with ground measurements used for validation. The model estimates of surface energy fluxes compared well with ground-based measurements of surface flux (typically within approximately 40 Wm?2). The model accuracy may be slightly less for bare soil surfaces due to an overestimation of the soil heat flux. In addition to demonstrating the feasibility of computing spatially distributed values of surface energy fluxes, these maps were used to qualitatively infer the dominant factors controlling the energy fluxes for the time period shortly following precipitation events in the basins. For the semi-arid watershed, values of sensible heat flux varied considerably over the watershed and displayed a pattern very similar to that of the spatially variable cumulative precipitation for at least one to eight days prior to the image acquisition. Due to the large fraction of exposed bare soil in a semi-arid ecosystem, even very small precipitation events had a strong influence on the pattern of sensible heat fluxes observed shortly after the event (less than 24 hours). For the sub-humid watershed, the fluxes tended to be more uniform across the watershed, and were influenced by a combination of precipitation total and land cover type.  相似文献   

16.
This study is motivated by insufficiencies in two areas in the literature. First, some technical barriers have hindered investigations of changing job–housing patterns over time. Second, traditional dichotomous studies (black–white) of ethnically divided commuting patterns are insufficient to paint the big picture of such dynamics in a multiethnicity metropolitan area. This research fills the gap by presenting an approach to the spatio-temporal analysis of commuting patterns by ethnicity. A case study is performed to track changing commuting patterns for whites, blacks, and Latinos in Atlanta over the last two decades. The results shed light on our understanding of the changing job–housing dynamics, particularly that of Latinos.  相似文献   

17.
In this article, we examine graffiti abatement policies and programs in three West Coast U.S. cities: Portland, San Francisco, and Seattle. Through this analysis, several similarities in the graffiti abatement efforts of each city emerged. Since the 1990s, graffiti abatement efforts in these cities have become increasingly formalized and coordinated. By the early 2000s, the cities of Portland, San Francisco, and Seattle adopted zero-tolerance approaches toward handling graffiti and those caught making graffiti. City governments have placed increasing responsibility for cleaning up graffiti on private property onto property owners. Despite the increased coordination and effort, annual abatement estimates are hard to obtain because tracking spending on graffiti abatement across agencies and bureaus is difficult and often the cities do not comprehensively compile these data.  相似文献   

18.
19.
The spatial correlation, or colocation, of two or more variables is a fundamental issue in geographical analysis but has received much less attention than the spatial correlation of values within a single variable, or autocorrelation. A recent paper by Leslie and Kronenfeld (2011) contributes to spatial correlation analysis in its development of a colocation statistic for categorical data that is interpreted in the same way as a location quotient, a frequently used measure in human geography and other branches of regional analysis. Geographically weighted colocation measures for categorical data are further developed in this article by generalizing Leslie and Kronenfeld's global measure as well as specifying a local counterpart for each global statistic using two different types of spatial filters: fixed and adaptive. These geographically weighted colocation quotients are applied to the spatial distribution of housing types to demonstrate their utility and interpretation.  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号