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51.
《Urban geography》2013,34(7):589-590
By simultaneously controlling for the spatial and social characteristics of neighborhoods, this study sheds new empirical light on the relationship between ethnic-enclave residence and ethnic-niche employment. Considering women's commuting constraints and their theoretically more local social networks, this study explores whether residential segregation may be a more important determinant of labor-market segregation for immigrant women than for men. The study finds that residential segregation plays an important role in sustaining labor-market segregation among immigrants, and that gender emerges as a salient mediating factor. While living in an ethnic enclave tends to be associated with ethnic-niche employment for both men and women, women who live in enclave neighborhoods have a higher rate of ethnic-niche employment than men. However, greater geographic accessibility to niche jobs is associated with niche employment for both immigrant men and women in general, and place-based context seems as important to men as women. 相似文献
52.
《Urban geography》2013,34(1):66-82
Measuring the level of segregation often encounters two methodological issues: measures are sensitive to changes in the geographical scale of the data and the effectiveness of the measure in reflecting spatial segregation. Several spatial measures have been suggested to measure spatial segregation, but whether they are more or less sensitive to changes in spatial scale has not been investigated, while some spatial measures are relatively scale-insensitive. Using the 1990 Census data of 30 selected U.S. metropolitan areas, this paper demonstrates that these spatial measures, similar to the aspatial measure, report higher levels of segregation when smaller areal units are used in the analysis. Some spatial measures are even more sensitive to scale changes than aspatial measures. Certain patterns of the scale sensitivity were identified, but no general rules can be formulated. A preliminary explanation of the scale effect on spatial segregation measures is offered. 相似文献
53.
《Urban geography》2013,34(7):587-609
Poverty segregation increased in Southern California during the 1990s. A comparison of four indices reflecting various dimensions of segregation (e.g., evenness, concentration, isolation, and clustering) suggests that poor people are increasingly concentrated and isolated. However, cities within the region experienced different levels and types of segregation, with significant changes over time. Regression analysis using 1990 and 2000 census data highlights the role of demographic, economic, and fiscal variables in explaining the changing landscape of poverty. Whereas historically poor and older cities have seen a rise in poverty that translated into an increase in concentration and isolation, newer suburban communities have evolved differently. Cities where poverty has been high and increasing often maintained a high level of clustering and unevenness, but experienced higher levels of concentration and clustering in 2000. In contrast, wealthier cities typically faced a rise in unevenness and clustering as small pockets of poverty population emerged in the midst of high-income neighborhoods. 相似文献
54.
《Urban geography》2013,34(5):514-542
In this article, we examine the sociospatial effects of market-driven social housing policies implemented in neoliberal Chile. The study area encompasses the Valparaíso—Viña del Mar conurbation and its surrounding peri-urban and peripheral municipalities. To analyze the urban dynamic between 1990 and 2005 we use data showing the allocation of social housing complexes built during three time periods, socioeconomic data disaggregated at the district level, and semistructured interviews conducted with strategic actors from the public and private sectors. We conclude that private developers are increasingly building social housing complexes in peripheral municipalities, fragmenting the sociospatial landscape and concentrating poor families in ghetto-like compounds. We also encountered local governments (municipalities) with little capacity to mobilize the resources that they hold, and communities that remain disconnected from their local representatives. 相似文献
55.
《Urban geography》2013,34(4):531-567
Scholars have often discounted social class as a substantial contributor to residential segregation by race, in part as a result of using the dissimilarity index, which is likely to show high levels of uneven group distribution regardless of socioeconomic status (SES), and in part as a result of using limited categories of SES. This study expands on prior research by examining residential segregation between black-alone and white-alone households in 36 metropolitan statistical areas (MSAs) with 2000 decennial census data, using both spatial unevenness (dissimilarity) and two types of experiential indicators (exposure indices), measuring SES across income levels and accounting for the presence of other races. Findings show that black households with higher incomes live in neighborhoods with greater exposure and lower isolation than do black households with lower incomes. Additionally, while the dissimilarity of black households decreases with income, unevenness is not as strongly connected to income as are the experiential measures. While race remains a primary determinant of residential segregation, results indicate substantial class differences. 相似文献
56.
《Urban geography》2013,34(4):589-605
This progress report is third in a series that examines the causes of segregation and the meaning and measurement of segregation. In this final report, we begin with the premise that ethnic and racial segregation carries tremendous impacts on the groups involved, altering their daily patterns and their future prospects. Yet the types of consequences that result from segregation depend on group dynamics; the social, political, and economic context; and a variety of contingent circumstances. In this essay, we review the recent literature on the outcomes of urban ethnic segregation and focus on some major themes that emerge from the literature. These themes include health and deprivation effects, how segregation can influence the group's employment prospects, how the fact of concentration may alter degrees of tolerance and intolerance, how segregation can augment levels of crime and violence, and finally the extent to which segregation influences the political and civic life of minority groups. 相似文献
57.
《Urban geography》2013,34(5):691-709
Municipalities create a local political geography that can institutionalize subordinate positions for minority groups. Most importantly, local governments determine which areas are incorporated into a municipality through annexation and which are excluded. Through these powers, local governments can diminish or deny minority political standing in local affairs, limit access to public services, and reduce the value of minority property. The boundaries are a component of racial residential segregation. Racially disparate application of local governments' power to shape local political geography creates barriers to equality that are difficult to discern on the ground, but which can be made visible by the mapping of spatial data. This study presents four cases where governmental decisions concerning a municipal boundary have institutionalized racial inequality, which is documented with maps created from public GIS data and other public records (e.g., City Council meeting minutes) as well as legal documents. This pattern of systematic exclusion of minority neighborhoods is receiving attention in the legal community, but studies in the social sciences have been limited. 相似文献
58.
59.
云南富宁地区铜镍矿成矿地质条件分析 总被引:1,自引:0,他引:1
铜镍是富宁地区主要矿种。成矿母岩为"安定型"基性岩。岩体具有明显的分异现象,自边缘至中心可分成致密状辉绿岩相、中细粒橄榄辉长苏长岩相、中粒辉长苏长岩相、中粒闪长岩相四个相带。铜镍矿主要产于中细粒橄榄辉长苏长岩相中,其次产于中粒辉长苏长岩相中。对富宁地区铜镍矿成矿地质条件进行分析。 相似文献
60.
The three most crucial factors for the formation of large and super-large magmatic sulfide
deposits are: (1) a large volume of mantle-derived mafic-ultramafic magmas that participated in the
formation of the deposits; (2) fractional crystallization and crustal contamination, particularly the input
of sulfur from crustal rocks, resulting in sulfide immiscibility and segregation; and (3) the timing of
sulfide concentration in the intrusion. The super-large magmatic Ni-Cu sulfide deposits around the world
have been found in small mafic-ultramafic intrusions, except for the Sudbury deposit. Studies in the past
decade indicated that the intrusions hosting large and super-large magmatic sulfide deposits occur in
magma conduits, such as those in China, including Jinchuan (Gansu), Yangliuping (Sichuan), Kalatongke
(Xinjiang), and Hongqiling (Jilin). Magma conduits as open magma systems provide a perfect environment
for extensive concentration of immiscible sulfide melts, which have been found to occur along deep
regional faults. The origin of many mantle-derived magmas is closely associated with mantle plumes,
intracontinental rifts, or post-collisional extension. Although it has been confirmed that sulfide immiscibility
results from crustal contamination, grades of sulfide ores are also related to the nature of the
parental magmas, the ratio between silicate magma and immiscible sulfide melt, the reaction between
the sulfide melts and newly injected silicate magmas, and fractionation of the sulfide melt. The field relationships
of the ore-bearing intrusion and the sulfide ore body are controlled by the geological features of
the wall rocks. In this paper, we attempt to demonstrate the general characteristics, formation mechanism,tectonic settings, and indicators of magmatic sulfide deposits occurring in magmatic conduits which
would provide guidelines for further exploration. 相似文献