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81.
1. Egg size is often used as a proxy of egg quality although size and composition may vary, e.g. in insects egg size usually decreases as female ages. Whether this decrease in size reflects reduced concentrations of essential nutrients such as lipids and proteins of eggs laid by ageing females, or does reduced size per se explain often observed lower fitness of later laid eggs is poorly explored. 2. Egg properties were compared with fitness parameters of offspring laid on the first and fourth night during the oviposition period of a capital breeding moth, Cleorodes lichenaria (Hufnagel). The study aim was to explore whether decreased egg size is caused by decreased provisioning into later laid eggs measured as egg protein and lipid concentration, and whether it results in lower fitness of later laid offspring. 3. The fresh and dry weight of eggs decreased over the oviposition period, but the protein and lipid concentration remained constant. Survival of larvae was lower among the fourth night laid offspring on a low quality host Parmelia sulcata Taylor compared to a high quality host Ramalina fraxinea (L.) Ach. No differences were observed in egg fertility or hatchability, neonate survival without food and pupal mass between the offspring produced on different nights. 4. Decreased survival of offspring produced later was rather attributable to absolute provisioning (i.e. lower weight of eggs) than relative provisioning (i.e. decreased concentrations of nutrients in eggs). It is argued that lower survival of later laid smaller eggs on low quality diet is likely attributable to physical and chemical characteristics of host lichens and/or physical properties of tiny neonate larvae.  相似文献   
82.
Abstract

Ever since Putnam (2000) made social capital a concept that should be mourned for its decline in the USA, researchers and policy makers in some western countries have adopted it as a solution to what they believe to be the failed practices of multiculturalism. Instead of preserving their individual cultures and traditions, critics would have them build social capital by bridging to people and institutions in their new countries and adopt the ‘shared values’ of the host countries and become ‘integrated’. This study, based on a study conducted in the Netherlands in 2006, and supplemented with survey findings from Flanders at the same time, examines whether this perspective is accurate, focusing on women migrants who live in the Low Countries (Netherlands and Flanders in Belgium), of the networks they have built or not and the reasons for that, and of the role of media and the internet in that process.  相似文献   
83.
Taller children perform better on average on tests of cognitive achievement, in part because of differences in early-life health and net nutrition. Recent research documenting this height-achievement slope has primarily focused on rich countries. Using the India Human Development Survey, a representative sample of 40,000 households which matches anthropometric data to learning tests, this paper documents a height-achievement slope among Indian children. The height-achievement slope in India is more than twice as steep as in the U.S. An earlier survey interviewed some IHDS children's households eleven years before. Including matched early-life control variables reduces the apparent effect of height, but does not eliminate it; water, sanitation, and hygiene may be particularly important for children's outcomes. Being one standard deviation taller is associated with being 5 percentage points more likely to be able to write, a slope that falls only to 3.4 percentage points controlling for a long list of contemporary and early-life conditions.  相似文献   
84.
In this article, I seek to identify a limitation in the analysis James Scott offers in Seeing Like a State (1998) by asking to what extent his account of the follies of schemes for planned improvement by states provides critical leverage on the present world of neoliberal global capitalism. Scott has claimed that a dynamic of standardization, homogenization, and grid making applies not only to developmentalist states but also equally to the contemporary world of downsized states and unconstrained global corporations. I contest that claim by tracing how recent capital investment in Africa has been territorialized, and some of the new forms of order and disorder that have accompanied that selectively territorialized investment. Because such investment has been overwhelmingly in mineral resource extraction—particularly in oil—a contrast will become visible between the homogenizing, standardizing state optic Scott analyzed and a rather different way of seeing, proper to the contemporary global oil company.  相似文献   
85.
Human capital, wealth, and nutrition in the Bolivian Amazon   总被引:4,自引:0,他引:4  
We analyze anthropometric variables of a society of forager-horticulturalists in the Bolivian Amazon (Tsimane') in 2001-2002. Community variables (e.g., inequality, social capital) explain little of the variance in anthropometric indices of nutritional status, but individual-level variables (schooling, wealth) are positively correlated with nutritional status. Dietary quality (foods high in animal proteins), access to foraging technology, and traditional knowledge of medicinal plants are related to better anthropometric indices.  相似文献   
86.
Applications of stable isotope analyses to avian ecology   总被引:3,自引:0,他引:3  
RICHARD INGER  & STUART BEARHOP 《Ibis》2008,150(3):447-461
In the past 20 years the use of stable isotope analysis has become increasingly common in ecological studies. In fact, in some instances these techniques have yielded remarkable insights into the foraging preferences and migrations of birds. Despite these advances and the potential of the approach, it is possibly still not as widely used as might be expected. In this paper we aim to illustrate the potential of the approach in the hope of encouraging more avian ecologists to think again about how these techniques might provide insights in the systems on which they work. We discuss some of the principles behind the approach, and review some of the more recent ornithological studies that have used stable isotope techniques to trace trophic pathways or infer migratory origins. We follow this by discussing some of the latest ideas on how stable isotopes may be used to generate community metrics and close by detailing the important assumptions and caveats that should be considered before undertaking any studies using this technique.  相似文献   
87.
Life history trade-offs are often hierarchical with decisions at one level affecting lower level trade-offs. We investigated trade-off structure in female side-blotched lizards (Uta stansburiana), which exhibit two evolved strategies: yellow-throated females are K-strategists and orange-throated are r-strategists. Corticosterone treatment was predicted to differentially organize these females' reproductive decisions. Corticosterone-treated yellow females suppressed reproduction but survived well, and augmented egg mass without decreasing clutch size. Conversely, corticosterone enhanced mortality and reproductive rates in orange females, and increased egg mass only after lengthy exposure. Corticosterone did not affect post-laying condition, suggesting that corticosterone increased egg mass through enhanced energy acquisition (income breeding). Corticosterone enhanced survival of lightweight females, but decreased survival of heavy females, introducing a foraging vs. predation trade-off. We conclude that rather than being a direct, functional relationship, observed trade-offs between offspring size and number represent evolved differences in hierarchical organization of multidimensional trade-offs, particularly in response to stress.  相似文献   
88.
Group formation, social capital and collective action have been the focus of much recent attention amongst donors and policy makers. Optimistic scenarios highlight their contributions to poverty reduction and effective natural resource management. However, recent critiques have focused on the exclusionary potential or ‘dark side’ of groups and social capital. Not only are their longer term livelihood impacts unclear, but lacunae persist in our understanding of how social capital, especially trust, is built. This paper presents a longitudinal evaluation of trust, collective action and cooperation among herders in post-Soviet Mongolia in the context of recent donor projects. Results highlight the important catalytic effect of external interventions in overcoming a lack of trust and promoting formalised collective action, but only in the context of a particular conjunction of circumstances. Indications for livelihood outcomes confirm the differentiated benefits, exclusionary potential and fragility of social capital and new institutional forms.
Caroline UptonEmail:
  相似文献   
89.
This paper uses semi-structured interviews with Ecuadorian “white mestizos” of the upper classes to provide insights into the nature of racism in Ecuador. Interview data illuminate the specifics of racism and discrimination suffered by some of those labelled as mestizos, demolishing anew the idea of a homogenous mestizaje. Longo and cholo emerge as specific ethnic terminology used to create a racial/class distinctions among mestizos struggling for ethnoracial capital in a newly defined plurinational and intercultural state. These findings are contrasted with recent progressive state policies that address the plight of groups historically marginalized or ignored by the Ecuadorian narrative of mestizaje, but fail to look within mestizaje to battle against the remnants of colonial constructions of power and difference.  相似文献   
90.
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