120 resultados para Associations, institutions, etc.


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Drawing on a cultural, transnational and genealogical approach, this article studies the work of a Swiss missionary, Henri-Philippe Junod, between Europe and Africa. It tries not to look at what he brought to Africa, or brought back from Africa, but to see how his back-and-forth movement contributed to the formation of new ideas and institutions globally. The article looks at Junod’s contribution in three domains in particular, namely anthropology, human rights worldwide, and African studies in Switzerland.

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Predicting how species distributions might shift as global climate changes is fundamental to the successful adaptation of conservation policy. An increasing number of studies have responded to this challenge by using climate envelopes, modeling the association between climate variables and species distributions. However, it is difficult to quantify how well species actually match climate. Here, we use null models to show that species-climate associations found by climate envelope methods are no better than chance for 68 of 100 European bird species. In line with predictions, we demonstrate that the species with distribution limits determined by climate have more northerly ranges. We conclude that scientific studies and climate change adaptation policies based on the indiscriminate use of climate envelope methods irrespective of species sensitivity to climate may be misleading and in need of revision.

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Mycorrhizal associations, including ericoid, arbuscular and ecto-mycorrhizas, are found colonising highly metal contaminated soils. How do mycorrhizal fungi achieve metal resistance, and does this metal resistance confer enhanced metal resistance to plant symbionts? These are the questions explored in this review by considering the mechanistic basis of mycorrhizal adaptation to metal cations. Recent molecular and physiological studies are discussed. The review reappraises what constitutes metal resistance in the context of mycorrhizal associations and sets out the constitutive and adaptive mechanisms available for mycorrhizas to adapt to contaminated sites. The only direct evidence of mycorrhizal adaptation to metal cation pollutants is the exudation of organic acids to alter pollutant availability in the rhizosphere. This is not to say that other mechanism of adaptation do not exist, but conclusive evidence of adaptive mechanisms of tolerance are lacking. For constitutive mechanisms of resistance, there is much more evidence, and mycorrhizas possess the same constitutive mechanisms for dealing with metal contaminants as other organisms. Rhizosphere chemistry is critical to understanding the interactions of mycorrhizas with polluted soils. Soil pH, mineral weathering, pollutant precipitation with plant excreted organic acids all may have a key role in constitutive and adaptive tolerance of mycorrhizal associations present on contaminated sites. The responses of mycorrhizal fungi to toxic metal cations are diverse. This, linked to the fact that mycorrhizal diversity is normally high, even on highly contaminated sites, suggests that this diversity may have a significant role in colonisation of contaminated sites by mycorrhizas. That is, the environment selects for the fungal community that can best cope with the environment, so having diverse physiological attributes will enable colonisation of a wide range of metal contaminated micro-habitats.

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Norms constitute a powerful coordination mechanism among heterogeneous agents. In this paper, we propose a rule language to specify and explicitly manage the normative positions of agents (permissions, prohibitions and obligations), with which distinct deontic notions and their relationships can be captured. Our rule-based formalism includes constraints for more expressiveness and precision and allows to supplement (and implement) electronic institutions with norms. We also show how some normative aspects are given computational interpretation. © 2008 Springer Science+Business Media, LLC.

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The island of Mauritius offers the opportunity to study the poorly understood vegetation response to climate change on a small tropical oceanic island. A high-resolution pollen record from a 10 m long peat core from Kanaka Crater (560 m elevation, Mauritius, Indian Ocean) shows that vegetation shifted from a stable open wet forest Last Glacial state to a stable closed-stratified-tall-forest Holocene state. An ecological threshold was crossed at ∼11.5 cal ka BP, propelling the forest ecosystem into an unstable period lasting ∼4000 years. The shift between the two steady states involves a cascade of four abrupt (<150 years) forest transitions in which different tree species dominated the vegetation for a quasi-stable period of respectively ∼1900, ∼1100 and ∼900 years. We interpret the first forest transition as climate-driven, reflecting the response of a small low topography oceanic island where significant spatial biome migration is impossible. The three subsequent forest transitions are not evidently linked to climate events, and are suggested to be driven by internal forest dynamics. The cascade of four consecutive events of species turnover occurred at a remarkably fast rate compared to changes during the preceding and following periods, and might therefore be considered as a composite tipping point in the ecosystem. We hypothesize that wet gallery forest, spatially and temporally stabilized by the drainage system, served as a long lasting reservoir of biodiversity and facilitated a rapid exchange of species with the montane forests to allow for a rapid cascade of plant associations.

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A free association test was used in the present study to examine the availability and accessibility of positive vs negative smoking-related information in the long-term memories of smokers. Participants were asked to generate smoking-related associations across a 4-minute interval. Although smokers generated more positive smoking-associations than non-smokers, both groups produced a greater number of negative than positive associations per se. Of particular interest was the finding that whilst the ratio of positive/negative associations generated was constant across time in non-smokers, this ratio varied in smokers. Specifically, smokers generated proportionately more of their available positive associations and proportionately less of their negative associations in the early time interval. It is suggested that these results not only indicate a greater availability of positive smoking-associations in smokers compared to non-smokers, but also a greater accessibility too. It is proposed that positive smoking associations are more automatically activated than negative associations in smokers, even though they have generally more negative associations available.

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OBJECTIVE-To examine associations of neonatal adiposity with maternal glucose levels and cord serum C-peptide in a multicenter multinational study, the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study, thereby assessing the Pederson hypothesis linking maternal glycemia and fetal hyperinsulinemia to neonatal adiposity. RESEARCH DESIGN AND METHODS-Eligible pregnant women underwent a standard 75-g oral glucose tolerance test between 24 and 32 weeks gestation (as close to 28 weeks as possible). Neonatal anthropometrics and cord serum C-peptide were measured. Associations of maternal glucose and cord serum C-peptide with neonatal adiposity (sum of skin folds >90th percentile or percent body fat >90th percentile) were assessed using multiple logistic regression analyses, with adjustment for potential confounders, including maternal age, parity, BMI, mean arterial pressure, height, gestational age at delivery, and the baby's sex. RESULTS-Among 23,316 HAPO Study participants with glucose levels blinded to caregivers, cord serum C-peptide results were available for 19,885 babies and skin fold measurements for 19,389. For measures of neonatal adiposity, there were strong statistically significant gradients across increasing levels of maternal glucose and cord serum C-peptide, which persisted after adjustment for potential confounders. In fully adjusted continuous variable models, odds ratios ranged from 1.35 to 1.44 for the two measures of adiposity for fasting, 1-h, and 2-h plasma glucose higher by 1 SD. CONCLUSIONS-These findings confirm the link between maternal glucose and neonatal adiposity and suggest that the relationship is mediated by fetal insulin production and that the Pedersen hypothesis describes a basic biological relationship influencing fetal growth. © 2009 by the American Diabetes Association.