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1.
Many studies have provided evidence that, in birds, inexperienced breeders have a lower probability of breeding successfully. This is often explained by lack of skills and knowledge, and sometimes late laying dates in the first breeding attempt. There is growing evidence that in many species with deferred reproduction, some prebreeders attend breeding places, acquire territories and form pairs. Several behavioural tactics assumed to be associated with territory acquisition have been described in different species. These tactics may influence the probability of recruiting in the breeding segment of the population, age of first breeding, and reproductive success in the first breeding attempt. Here we addressed the influence of behaviour ('squatting') during the prebreeding period on demographic parameters (survival and recruitment probability) in a long-lived colonial seabird species: the kittiwake. We also investigated the influence of behaviour on reproductive trajectory. Squatters have a higher survival and recruitment probability, and a higher probability of breeding successfully in the first breeding attempt in all age-classes where this category is represented. The influence of behaviour is mainly expressed in the first reproduction. However, there is a relationship between breeding success in the first occasion and subsequent occasions. The influence of breeding success in the first breeding attempt on the rest of the trajectory may indirectly reflect the influence of behaviour on breeding success in the first occasion. The shape of the reproductive trajectory is influenced by behaviour and age of first breeding. There is substantial individual variation from the mean reproductive trajectory, which is accounted for by heterogeneity in performance among individuals in the first attempt, but there is no evidence of individual heterogeneity in the rate of change over time in performance in subsequent breeding occasions  相似文献   
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Many studies have provided evidence that, in birds, inexperienced breeders have a lower probability of breeding successfully. This is often explained by lack of skills and knowledge, and sometimes late laying dates in the first breeding attempt. There is growing evidence that in many species with deferred reproduction, some prebreeders attend breeding places, acquire territories and form pairs. Several behavioural tactics assumed to be associated with territory acquisition have been described in different species. These tactics may influence the probability of recruiting in the breeding segment of the population, age of first breeding, and reproductive success in the first breeding attempt. Here we addressed the influence of behaviour ('squatting') during the prebreeding period on demographic parameters (survival and recruitment probability) in a long-lived colonial seabird species: the kittiwake. We also investigated the influence of behaviour on reproductive trajectory. Squatters have a higher survival and recruitment probability, and a higher probability of breeding successfully in the first breeding attempt in all age-classes where this category is represented. The influence of behaviour is mainly expressed in the first reproduction. However, there is a relationship between breeding success in the first occasion and subsequent occasions. The influence of breeding success in the first breeding attempt on the rest of the trajectory may indirectly reflect the influence of behaviour on breeding success in the first occasion. The shape of the reproductive trajectory is influenced by behaviour and age of first breeding. There is substantial individual variation from the mean reproductive trajectory, which is accounted for by heterogeneity in performance among individuals in the first attempt, but there is no evidence of individual heterogeneity in the rate of change over time in performance in subsequent breeding occasions  相似文献   
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A quantitative microbial risk assessment (QMRA) according to the Codex Alimentarius Principles is conducted to evaluate the risk of human salmonellosis through household consumption of fresh minced pork meat in Belgium. The quantitative exposure assessment is carried out by building a modular risk model, called the METZOON-model, which covers the pork production from farm to fork. In the METZOON-model, the food production pathway is split up in six consecutive modules: (1) primary production, (2) transport and lairage, (3) slaughterhouse, (4) postprocessing, (5) distribution and storage, and (6) preparation and consumption. All the modules are developed to resemble as closely as possible the Belgian situation, making use of the available national data. Several statistical refinements and improved modeling techniques are proposed. The model produces highly realistic results. The baseline predicted number of annual salmonellosis cases is 20,513 ( SD 9061.45). The risk is estimated higher for the susceptible population (estimate  4.713 × 10−5; SD 1.466 × 10−5  ) compared to the normal population  (estimate 7.704 × 10−6; SD 5.414 × 10−6)  and is mainly due to undercooking and to a smaller extent to cross-contamination in the kitchen via cook's hands.  相似文献   
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The Access/Impact Problem and the Green and Gold Roads to Open Access   总被引:3,自引:0,他引:3  
The research access/impact problem arises because journal articles are not accessible to all of their would-be users; hence, they are losing potential research impact. The solution is to make all articles Open Access (OA; i.e., accessible online, free for all). OA articles have significantly higher citation impact than non-OA articles. There are two roads to OA: the “golden” road (publish your article in an OA journal) and the “green” road (publish your article in a non-OA journal but also self-archive it in an OA archive). Only 5% of journals are gold, but over 90% are already green (i.e., they have given their authors the green light to self-archive); yet only about 10–20% of articles have been self-archived. To reach 100% OA, self-archiving needs to be mandated by researchers' employers and funders, as the United Kingdom and the United States have recently recommended, and universities need to implement that mandate.  相似文献   
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An important source of conflict surrounding nuclear energy is that with a very small probability, a large-scale nuclear accident may occur. One way to internalize the associated financial risks is through mandating nuclear operators to have liability insurance. This paper presents estimates of consumers' willingness to pay for increased financial security provided by an extension of coverage, based on the 'stated choice' approach. A Swiss citizen with median characteristics may be willing to pay 0.14 US cents per kwh to increase coverage beyond the current CHF 0.7 billion (bn.) (US$ 0.47 bn.). Marginal willingness to pay declines with higher coverage but exceeds marginal cost at least up to CHF 4 bn.(US$ 2.7 bn.). An extension of nuclear liability insurance coverage therefore may be efficiency-enhancing.  相似文献   
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To “review the urban question” in terms of sustainable development, the premise is formulated that improving infrastructures, equipment and services to preserve the natural and built urban environment is costly and generates expenses of all kinds—at economic and social levels. Without the introduction of equalisation mechanisms, these expenses will increase inequalities between different parts of the urban population.As confirmed by 2 Latin American case studies in Buenos Aires, Argentina, and La Paz Bolivia, the quality of urban environment depends directly on improving living conditions for the resident population. The aim is to assist the poor in developing a rubbish disposal service for the families living in the informal settlements of La Paz, or to extend water supply to the poorer areas on the outskirts of Buenos Aires. The collective benefits of these “innovations” are self-evident. However, understanding the environmental issues involved, and evaluating the social impact of these innovations, means examining what motivates their implementation.The first difficulty was in finding financial and economic information on the global cost of the new technologies, due to the lack of managerial culture and the discretional attitude of private enterprises and public administration.A second observation is that the social dimension of the environmental upgrading process in Latin America cities has been neglected by the main urban decision-makers. In all the contexts, the evolution of the projects’ implementation clearly demonstrates that social issues cannot be dissociated from political ones. Although the players themselves often find it difficult to estimate economic costs, these are nonetheless real and represent burdens that should be distributed equitably among the beneficiaries of services; but which are, in practice, often viewed in terms of profit. This leads to conflicts between different population groups, the political authorities and private intermediaries.Rather than viewing technological action as an unique “source” of innovation, we must consider its global dimension via the social practices it generates. On the other hand, we should reposition every specific event in its immediate environment and see how it reflects contemporary macro-social processes, in a world of “globalisation”.  相似文献   
10.
The authors consider the problem of estimating the density g of independent and identically distributed variables XI, from a sample Z1,… Zn such that ZI = XI + σ? for i = 1,…, n, and E is noise independent of X, with σ? having a known distribution. They present a model selection procedure allowing one to construct an adaptive estimator of g and to find nonasymptotic risk bounds. The estimator achieves the minimax rate of convergence, in most cases where lower bounds are available. A simulation study gives an illustration of the good practical performance of the method.  相似文献   
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