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1.
We study prevalence of son preference in families of East and South Asian origin living in the USA by investigating parental time investments in children using American Time Use Surveys. Estimates show that East and South Asian mothers spend an additional hour of quality time per day with their young (aged 0–2 years) sons than with young daughters; son preference in mothers’ time allocation declines as children get older. East and South Asian fathers’ time with young children is gender neutral. We find gender specialization in time with children aged 6–17 with fathers spending more time with sons and mothers spending more time with daughters.  相似文献   
2.
Urban areas are understood to be extraordinarily spatially heterogeneous. Spatial heterogeneity, and its causes, consequences, and changes, are central to ecological science. The social sciences and urban design and planning professions also include spatial heterogeneity as a key concern. However, urban ecology, as a pursuit that integrates across these disciplines, lacks a theoretical framework that synthesizes the diverse and important aspects of heterogeneity. This paper presents the concept of dynamic heterogeneity as a tool to explore how social and ecological heterogeneities interact and how they together act as both an outcome of past interactions and a driver future heterogeneity and system functions. To accomplish this goal, we relate heterogeneity to the fundamental concept of the human ecosystem. The human ecosystem concept identifies key processes that require operationalized models of dynamic heterogeneity in three process realms: the flow of materials, the assembly of urban ecosystem biota, and the locational choices humans make concerning land. We exemplify a specific dynamic model of heterogeneity in each of these realms, and indicate a range of complementary statistical approaches to integrate the drivers and outcomes of dynamic heterogeneity across the three realms. We synthesize a hierarchical framework for a theory of dynamic urban heterogeneity, noting its complementarity to other major urban theories and general model approaches. We hypothesize that human actions and structures amplify the dynamics of heterogeneity in urban systems.  相似文献   
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Social-ecological science in the humane metropolis   总被引:1,自引:0,他引:1  
The Humane metropolis is a rubric to summarize and promote environmental and social quality in contemporary urban mosaics. Because cities, suburbs, and exurbs, as spatially extensive and connected socio-ecological systems, exhibit many negative features, the humane metropolis identifies a strategy to combat the ills and instill more positive and sustainable features and processes in urban systems. Because the humane metropolis as a program has arisen primarily from social motivations, there is the opportunity to articulate more explicitly the role that science can play in addressing the humane metropolis program and evaluating its success. A humane metropolis can be summarized as one that 1) protects and restores ecological services in cities and suburbs, 2) promotes physical and mental health and safety of residents, 3) enhances efficiency by conserving energy, matter, water, and time, 4) facilitates equity by being inclusive, as well as socially and environmentally just, and 5) maintains a sense of community and a sense of place. We clarify the nature of science as a contributor to the social program, pointing out the social values motivating science, and the role that scientific knowledge and metaphor play in linking science with the social program of the humane metropolis. We further identify roles that socio-ecological research can play in meeting the goals of the humane metropolis. We use examples of environmental history, watershed function and restoration, and environmental justice research and action from the Baltimore Ecosystem Study, Long-Term Ecological Research program. The humane metropolis as a social program benefits from scientific contributions that 1) expose hidden ecological processes in urban systems, 2) generate knowledge connecting people and institutions to the biophysical environment, 3) contribute to the civic dialog, and 4) bring scientific values to the prioritization and balancing of the goals of the humane metropolis.  相似文献   
5.
We study the short-term trajectories of employment, hours worked, and real wages of immigrants in Canada and the USA using nationally representative longitudinal datasets covering 1996–2008. Models with person fixed effects show that, on average, immigrant men in Canada do not experience any relative growth in these three outcomes compared to men born in Canada. Immigrant men in the USA, on the other hand, experience positive annual growth in all three domains relative to US-born men. This difference is largely on account of low-educated immigrant men, who experience faster or longer periods of relative growth in employment and wages in the USA than in Canada. We further compare longitudinal and cross-sectional trajectories and find that the latter over-estimate wage growth of earlier arrivals, presumably reflecting selective return migration.  相似文献   
6.
Using large‐scale census data and adjusting for sending‐country fixed effect to account for changing composition of immigrants, we study relative immigrant selection to Canada and the U.S. during 1990–2006, a period characterized by diverging immigration policies in the two countries. Results show a gradual change in selection patterns in educational attainment and host‐country language proficiency in favor of Canada as its post‐1990 immigration policy allocated more points to the human capital of new entrants. Specifically, in 1990, new immigrants in Canada were less likely to have a B.A. degree than those in the U.S.; they were also less likely to have a highschool or lower education. By 2006, Canada surpassed the U.S. in drawing highly educated immigrants, while continuing to attract fewer low‐educated immigrants. Canada also improved its edge over the U.S. in terms of host‐country language proficiency of new immigrants. Entry‐level earnings, however, do not reflect the same trend: Recent immigrants to Canada have experienced a wage disadvantage compared to recent immigrants to the U.S., as well as Canadian natives. One plausible explanation is that while the Canadian points system has successfully attracted more educated immigrants, it may not be effective in capturing productivity‐related traits that are not easily measurable.  相似文献   
7.
This paper examines the association between poverty and food insecurity among children, using two different definitions of poverty – the official poverty measure (OPM) and the new supplemental poverty measure (SPM) of the Census Bureau, which is based on a more inclusive definition of family resources and needs. Our analysis is based on data from the 2001–2011 Current Population Survey and shows that food insecurity and very low food security among children decline as income-to-needs ratio increases. The point estimates show that the associations are stronger as measured by the new supplemental measure of income-to-needs ratio than when estimated through the official measure. Statistical tests reject the hypothesis that poor households' odds of experiencing low food security are the same whether the SPM or OPM measure is used; but the tests do not reject the hypothesis when very low food security is the outcome.  相似文献   
8.
Journal of Management and Governance - The study applies dynamic capability theory to investigate the combined impact of the two mediators management controls and managerial risk taking in the...  相似文献   
9.
The urban watershed continuum: evolving spatial and temporal dimensions   总被引:5,自引:3,他引:2  
Urban ecosystems are constantly evolving, and they are expected to change in both space and time with active management or degradation. An urban watershed continuum framework recognizes a continuum of engineered and natural hydrologic flowpaths that expands hydrologic networks in ways that are seldom considered. It recognizes that the nature of hydrologic connectivity influences downstream fluxes and transformations of carbon, contaminants, energy, and nutrients across 4 space and time dimensions. Specifically, it proposes that (1) first order streams are largely replaced by urban infrastructure (e.g. storm drains, ditches, gutters, pipes) longitudinally and laterally within watersheds, (2) there is extensive longitudinal and lateral modification of organic carbon and nutrient retention in engineered headwaters (3) there are longitudinal downstream pulses in material and energy exports that are amplified by interactive land-use and hydrologic variability, (4) there are vertical interactions between leaky pipes and ground water that influence stream solute transport, (5) the urban watershed continuum is a transformer and transporter of materials and energy based on hydrologic residence times, and (6) temporally, there is an evolution of biogeochemical cycles and ecosystem functions as land use and urban infrastructure change over time. We provide examples from the Baltimore Ecosystem Study Long-Term Ecological (LTER) site along 4 spatiotemporal dimensions. Long-term monitoring indicates that engineered headwaters increase downstream subsidies of nitrate, phosphate, sulfate, carbon, and metals compared with undeveloped headwaters. There are increased longitudinal transformations of carbon and nitrogen from suburban headwaters to more urbanized receiving waters. Hydrologic connectivity along the vertical dimension between ground water and leaky pipes from Baltimore??s aging infrastructure elevates stream solute concentrations. Across time, there has been increased headwater stream burial, evolving stormwater management, and long-term salinization of Baltimore??s drinking water supply. Overall, an urban watershed continuum framework proposes testable hypotheses of how transport/transformation of materials and energy vary along a continuum of engineered and natural hydrologic flowpaths in space and time. Given interest in transitioning from sanitary to sustainable cities, it is necessary to recognize the evolving relationship between infrastructure and ecosystem function along the urban watershed continuum.  相似文献   
10.
We examine the extent to which disparities in wealth by race/ethnicity are related to gaps in children's educational outcomes, and find that family socio-demographics and parental resources account for a substantial proportion of black/white and Hispanic/white disparities in children's participation in gifted programs, extracurricular activities and grade retention. Black children, however, continue to face high risk of expulsion or suspension from school relative to white children even in models that control for a rich set of socio-demographic and economic characteristics. The adjusted risk of expulsion and suspension faced by Hispanic children is found to be lower than that for white children. Indicators of wealth, after controlling for all other factors, had statistically significant associations with all outcomes except a child's suspension or expulsion from school. Having a checking or savings account was independently associated with participation in gifted programs and extracurricular activities.  相似文献   
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