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31.
32.
Conservation biology aims at assessing the status of a population, based on information which is often incomplete. Integrated population modelling based on state‐space models appears to be a powerful and relevant way of combining into a single likelihood several types of information such as capture‐recapture data and population surveys. In this paper, the authors describe the principles of integrated population modelling and they evaluate its performance for conservation biology based on a case study, that of the black‐footed albatross, a northern Pacific albatross species suspected to be impacted by longline fishing 相似文献
33.
Tracey Maegusuku‐Hewett David Dunkerley Jonathan Scourfield Nina Smalley 《Children & Society》2007,21(4):309-321
This article aims to makes a contribution to redressing a methodological and theoretical imbalance in existing research on refugee and asylum‐seeking children. It draws on two qualitative studies from Wales with children and young people. The samples include unaccompanied minors and children living with families as well as both children who are supported in the asylum system and those who have been granted refugee status. The focus on ecological post‐migratory stressors and coping processes that young people identify as being integral to their well‐being and, once granted status, to how they adapt to settlement includes a selective study of some of the sources of resilience referred to in the children's talk. Recognising the interplay between individual and environment leads to a discussion of both personal attributes and collective cultural identities. 相似文献
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35.
Information presented concurrently and redundantly to 2 or more senses (intersensory redundancy) has been shown to recruit attention and promote perceptual learning of amodal stimulus properties in animal embryos and human infants. This study examined whether the facilitative effect of intersensory redundancy also extends to the domain of memory. We assessed bobwhite quail chicks' ability to remember and prefer an individual maternal call presented either unimodally or redundantly and synchronously with patterned light during the period prior to hatching. Embryos provided with unimodal auditory exposure failed to prefer the familiar call over a novel maternal call postnatally at 48 hr and 72 hr following exposure. In contrast, embryos provided with redundant, synchronous audiovisual stimulation significantly preferred the familiar call at 48 hr following exposure, but not at 72 hr. A second experiment provided chicks with a single 10‐min refamiliarization with the familiar call at either 48 hr or 72 hr following hatching. Chicks given only unimodal auditory exposure prior to hatching did not appear to benefit from this brief postnatal refamiliarization, showing no preference for the familiar call at either 72 or 96 hr. Chicks that received redundant audiovisual stimulation prenatally showed a significant preference for the familiar call (following the brief reexpo sure 24 hr earlier) at both 72 and 96 hr of age. These results are the first to demonstrate that redundantly specified information is remembered longer and reactivated more easily than the same information presented unimodally. These findings provide further evidence of the salience of intersensory redundancy in guiding selective attention and perceptual learning during early development. 相似文献
36.
Robert C. Feenstra 《Journal of Policy Modeling》1985,7(1):49-68
We examine the effects of the U.S.-Japan trade restraint on automobile prices and quality upgrading, for both Japanese imports and American small cars. From April 1981 to April 1984 the suggested retail price of all Japanese models increased by 15.8 percent, or 5.3 percent per year. We find that nearly the entire amount of this rise can be explained by the upgrading of individual models. This upgrading may benefit consumers who would purchase a luxury import in any case, but harms those who desire the basic imports. In addition to upgrading, we conclude that a second cost of the trade restraint has been to prevent the yen depreciation from being passed onto American consumers, in terms of lower imported auto prices. For U.S. small cars we find a 9.1 percent rise in the suggested retail price, or 3 percent per year, with a fraction of this amount due to model upgrading. If the yen depreciation had led to lower import prices without the trade restraint, then we expect that U.S. auto prices would have been lower, too. 相似文献
37.
Expectations, Capital Gains, and Income 总被引:2,自引:0,他引:2
A theoretical framework for the measurement of income under uncertainty is developed that addresses some long-standing controversies about the treatment of capital gains. The consequences for economic analysis and policy making are potentially serious, because the treatment of capital gains can significantly affect some major macroeconomic aggregates, including national income and savings, balance of payments deficits, government deficits, and depreciation. (JEL O47 , P44 , Q32 ) 相似文献
38.
39.
Robert N. Bellah 《Theory and Society》1992,21(3):409-414
40.
Emmanuelle Cam Bernard Cadiou James E. Hines Jean Yves Monnat 《Journal of applied statistics》2002,29(1):163-185
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