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ABSTRACT

Jennifer Lee and Min Zhou’s The Asian American Achievement Paradox is a remarkable analysis of the educational upward mobility of Chinese and Vietnamese Americans in Los Angeles. It also provides important insights about the status of contemporary Asian Americans more generally. While critical of the ‘model minority’ thesis, the authors take seriously the role of culture in fostering educational attainment. However, their emphasis on immigrant selectivity and individual psychology may be misplaced when it comes to understanding the achievement of second-generation groups.  相似文献   

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The great majority of species that lived on this earth have gone extinct. These extinctions are often explained by invoking changes in the environment, to which the species has been unable to adapt. Evolutionary suicide is an alternative explanation to such extinctions. It is an evolutionary process in which a viable population adapts in such a way that it can no longer persist. In this paper different models, where evolutionary suicide occurs are discussed, and the theory behind the phenomenon is reviewed.  相似文献   

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Timothy T. Yates 《CMAJ》1990,143(7):610
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Petry JJ 《Plastic and reconstructive surgery》2002,109(6):2171; author reply 2171
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Explaining productivity-diversity relationships in plants   总被引:8,自引:0,他引:8  
Tara K. Rajaniemi 《Oikos》2003,101(3):449-457
Relationships between productivity and diversity in plant communities have been widely documented. Unimodal productivity-diversity relationships are most common along natural productivity gradients, and fertilization generally reduces diversity. Five distinct hypotheses invoke changes in competition to explain why diversity should decline from intermediate to high productivity. Because experiments measuring the effects of competition on diversity are rare, four of the five hypotheses have not been directly tested, but each hypothesis makes unique predictions that allow for indirect tests. The indirect evidence is often conflicting, and while none of the hypotheses can be rejected, only the dynamic equilibrium hypothesis is consistently supported. A new hypothesis, however, is supported by indirect evidence and may help to explain the variation in the shape of productivity-diversity relationships, as well as the most common patterns. Diversity may be high in environments that promote size symmetric competition, where soil resources limit growth and are homogeneously distributed within the soil volume explored by individual plants. Conversely, diversity may be low in environments that promote size asymmetric competition, where light is limiting, or where soil resources are limiting and are patchily distributed within rooting zones.  相似文献   

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G Craigen  N Lazar  M Keatings 《CMAJ》1990,143(3):168-169
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In this essay, we present three case studies which suggest that sometimes we are better off supporting a so–called irrational suicide, and that emotional or psychological distress – even if medically controllable – might justify a suicide. We underscore how complicated these decisions are and how murky a physician's moral role can be. We advocate a more individualized route to end–of–life care, eschewing well–meaning, principled, generalizations in favor of a highly contextualized, patient–centered, approach. We conclude that our Western traditions of promoting reasoned behavior and life themselves may at times be counter–productive.  相似文献   

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Suicidal behavior is a leading cause of injury and death worldwide. Suicide has been associated with psychiatric illnesses such as depression and schizophrenia, as well as economic uncertainty, and social/cultural factors. This study proposes a neuroeconomic framework of suicide. Neuroeconomic parameters (e.g., risk-attitude, probability weighting, time discounting in intertemporal choice, and loss aversion) are predicted to be related to suicidal behavior. Neurobiological and neuroendocrinological substrates such as serotonin, dopamine, cortisol (HPA axis), nitric oxide, serum cholesterol, epinephrine, norepinephrine, gonadal hormones (e.g., estradiol and progesterone), dehydroepiandrosterone (DHEA) in brain regiouns such as the orbitofrontal/dorsolateral prefrontal cortex and limbic regions (e.g., the amygdala) may supposedly be related to the neuroeconomic parameters modulating the risk of suicide. The present framework puts foundations for "molecular neuroeconomics" of decision-making processes underlying suicidal behavior.  相似文献   

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