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141.
This paper uses longitudinal data from China to examine the causal relationship between structural social capital and health among Chinese older adults. We employ various econometric strategies to control for the potential endogeneity of social capital and account for the possible contextual confounding effects by including community-level social capital. We use three indicators to measure individuals’ general, physical, and mental health. Results indicate that social capital has a significant and positive effect on general and physical health. Based on our primary IV findings, a one standard-deviation increase in social capital leads to a 4.9 standard-deviation decrease in the probability of having bad health and a 2.2 standard-deviation decrease in physical activity limitations. Our results are robust to a series of sensitivity checks. Further analysis suggests heterogeneous effects by age but not by gender or area of residence.  相似文献   
142.
Over the past decade, Ecological Footprint has become one of the most popular and widespread indicators for sustainability assessment and resource management. However, its popularity has been coupled, especially in recent years, by the emergence of critical views on the indicator’s rationale, methodology and policy usefulness. Most of these criticisms commonly point to the inability of the Ecological Footprint to track the human-induced depletion of natural capital stocks as one of the main shortcomings of the methodology. Fully addressing this issue will require research efforts and, most likely, further methodological refinements. The aim of this paper is therefore to outline the basis of a new area of investigation in Ecological Footprint research, primarily aimed at implementing the distinction between the use of stocks and the use of flows in Ecological Footprint Accounting and debating its implications.  相似文献   
143.
Current debates about the resettlement issue in Laos point to the need to pay closer attention to the migrants' representations and practices. In this article, three biographies of recent settlers in Thongnamy (Bolikhamxay Province) are analysed to highlight some concrete mechanisms at work in this context of socio-economic change. People rely on a diversity of resources to make ends meet, with varying success. Kinship and social capital are vital resources, and land is a major concern for all. The migrants' agency (a dimension missing in more quantitative surveys) must, however, be framed against a local ‘arena’, which is itself entangled in the broader, national setting, as revealed by a discussion of the ethnic issue and the land allocation policy. Ultimately, this paper offers insights into the progressive social differentiation that takes place in a new, heavily populated and multi-ethnic village where access to land is now at stake.  相似文献   
144.
We investigated whether the maturation of oocyte follicular epithelium of lizard is affected by d-aspartic acid (d-Asp). Our results demonstrated that d-Asp is endogenously present in the oocytes, and its distribution varies during the reproductive cycle and following intraperitoneal administration. At previtellogenesis, it is observed in the cytoplasm and nucleus of pyriform cells, in intermediate cells, in some small cells of the granulosa, in the ooplasm, and in some thecal elements. At vitellogenesis, d-Asp is localized in the proximity of the zona pellucida, in the theca, and in the ooplasm. Injected d-Asp is mainly captured by pyriform cells and ooplasm of previtellogenic oocytes, but a moderate accumulation is evident in the cytoplasm of some small granulosa cells and in the theca. d-Asp also increases the ovarian and plasmatic levels of 17β-estradiol and decreases those of testosterone. As a direct and/or indirect consequence of d-Asp, previtellogenic oocytes grow up and mature, resulting in a higher accumulation of carbohydrates in the granulosa, zona pellucida, and ooplasm, but also a reduction in the thickness of the granulosa layer and an increase of the theca stratum. Taken together, our results show that d-Asp may be related to the synchrony of reproduction, either enhancing the growth and maturation of follicular epithelium or influencing its endocrine functions. (J Histochem Cytochem 58:157–171, 2010)  相似文献   
145.
1 The effect of supplementary feeding on growth and reproduction of three carnivorous plants species was investigated over a 6‐year period. Pinguicula alpina , P. villosa and P. vulgaris populations growing at two altitudes in a subarctic environment were fed with fruit flies ( Drosophila melanogaster ).
2 Fed plants increased in size relative to control plants during the first years. Subsequently a stable size difference between feeding levels was established. The weight of the over‐wintering part was higher in fed plants than in control plants.
3 The flowering frequency (i.e. proportion of plants in a population carrying flowers) was also higher in the fed plants. The proportion of flowering plants increased in the feeding treatment compared to control plants during more‐or‐less the whole experimental feeding period (5–6 years). Seed production also increased slowly in response to feeding.
4 No feeding effect on nitrogen and phosphorus concentrations in seeds and over‐wintering parts was found.
5 In most characteristics the high‐altitude populations were less responsive than populations growing at low altitude. In the high‐altitude population reproduction failed repeatedly, suggesting that seed output may be more dependent on abiotic factors than on resource availability in cold environments.
6 Pinguicula villosa and P. vulgaris used the new resources the same summer for increased leaf rosette growth and current reproduction, showing these species to be income breeders, while the third species ( P. alpina ) allocated a larger proportion to storage and future reproduction, characteristic of a capital breeder.  相似文献   
146.
Based on an extensive questionnaire survey in three cities in Northwest China, this article identifies the factors influencing the sole, couple and family migration of Han and Hui. We find that Han migrants are more utility-oriented and tend to circulate among different places in order to maximize their utility. Hui migrants are more likely to seek opportunities to settle in destinations with their families. They rely on Hui communities and dedicate themselves to creating networks and accumulating social capital for their families. We suggest that the accumulation of bonding capital does not necessarily suggest the increase or decrease of bridging capital. Moreover, the ethnic community should be regarded neither in negative nor positive terms but rather as a coin with two sides, pro and con. The ethnic community is a vessel, which migrants can use for minimizing risks, improving livelihoods and fostering the settlement of families.  相似文献   
147.
This study examines differences in the size and socio-economic resources of core discussion networks across national-origin groups and immigrant generation. The analysis is based on the Netherlands Longitudinal Lifecourse Study (2008–10), a nationally representative, large-scale survey of the Dutch population that contains an over-sample of first- and second-generation immigrants from Turkey and Morocco, the two largest non-western immigrant groups in the Netherlands. Results show that Dutch majority members have larger and more resourceful core discussion networks than Turks and Moroccans. Second-generation immigrants from Turkey and Morocco have larger core discussion networks than their foreign-born parents. However, there is no clear evidence for intergenerational increase in resources. The larger and more resourceful core discussion networks of the Dutch are partly attributable to the Dutch being higher educated and employed more often.  相似文献   
148.
For more than a century, white communities across the United States employed strategies to remain all-white, including violent acts, forcibly driving minorities out of town, and local ordinances. One particularly widespread and effective approach used by many towns to exclude certain groups of people from living in their towns was the creation of a ‘sundown town’. This paper seeks to examine the association between past sundown policies and one component of community life that many towns currently struggle with: economic development. By examining the racial histories and economic development activities of 428 towns in the Midwest and nontraditional South, the study examines whether historical legacy can carry over to the present and affect economic development. Findings suggest that former sundown towns currently pursue fewer economic development activities than towns that have a history of being inclusive, even after controlling for a community's assets.  相似文献   
149.
150.
Little is known about whether breastfeeding may prevent disabilities throughout childhood. We evaluate the effects of breastfeeding on child disability using data from the National Survey of Family Growth merged to the National Health Interview Survey for a large nationally representative sample of children aged 1–18 years from the U.S. including over 3000 siblings who are discordant on breastfeeding status/duration. We focus on a mother fixed effect model that compares siblings in order to account for family-level unobservable confounders and employ multiple specifications including a dynamic model that accounts for disability status of the prior child. Breastfeeding the child for a longer duration is associated with a lower risk of child disability, by about 0.2 percentage-points per month of breastfeeding. This effect is only observed on the intensive margin among breastfed children, as any breastfeeding has no effect on the extensive margin. We conclude that very short breastfeeding durations are unlikely to have an effect on reducing disability risk.  相似文献   
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