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41.
Justin Gross Fran?ois Elvinger Laura L. Hungerford Stanley D. Gehrt 《Urban Ecosystems》2012,15(3):667-682
The raccoon is often considered a synanthropic species; however, most urban research on this species has been restricted to urban parks or green spaces. Little is known about the persistence of synanthropic characteristics in the raccoon within the urban matrix. We examined density, den selection, home range size, habitat selection, and survival for adult raccoons (Procyon lotor) during summer (June?CAugust) and autumn (September?CNovember) in two residential neighborhoods, Linthicum located inland, and Riviera Beach on a peninsula in the Potomac river, in Southern Maryland. Den site selection varied by gender (P?=?0.0002) and study site (P?=?0.052), and study site interacted with gender (P?=?0.0063), with female raccoons denning preferentially on the ground and male raccoons in human structures in Riviera Beach while in Linthicum females denned preferentially in trees and males avoided human structures. Seasonal home range size was larger for males (P?<?0.0001) than females at both sites. Habitat selection varied at different hierarchical levels, and between gender, season and site. Intersite differences in habitat selection were apparent at the second order and third order scale. Aquatic and urban habitat was ranked high and woodland consistently lowest in second order scale at Riviera Beach while urban habitat was consistently ranked lowest at Linthicum where woodland ranked highest. Between the hierarchal scales (2nd and 3rd order) a difference in habitat selection occurred at Linthicum only where urban habitats ranked lowest at 3rd order. The differences in patterns of habitat selection we observed between two urban sites at different hierarchical scales suggest that resource selection is dependent upon the specific characteristics of the site and that raccoons exhibit variable responses to changes in landscape features. Finally, male survival tended to be lower (P?=?0.079) than female survival in both study sites. Our results reveal that raccoons can continue to exhibit synanthropic characteristics within the urban matrix even in areas with little natural habitat. This ability to adjust to different levels of development allows the raccoon to occur throughout most parts of the urban landscape, which has important management implications for human-raccoon conflicts and disease management. 相似文献
42.
This article highlights the need for clinicians who work with eating disorders and body image problems to address the deeper family issues underlying these symptoms. The authors propose an eclectic approach including family systems, structural and experiential family therapy theory as a guide. The paper begins with an overview of family therapy theories currently used in the treatment of eating disorders, and goes into greater detail about the three theories highlighted in the eclectic model proposed. The authors present two cases with actual case dialogue, demonstrating how they used this composite model. This article has both theoretical and practical implications for clinicians working in the field. 相似文献
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The purpose of this paper is to explain why low-wage workers with identical qualifications to higher-wage workers are more exposed to unemployment. Each worker is considered to belong to a social group (defined according to his/her gender, age, and nationality). We assume that workers experience both productive interdependencies and social interactions within the firm. Also inter- and intra-group interactions determine worker productivity, and frictions on the labor market limit the hiring of the most productive workers. Consequently, externalities acting both within the firm and in the labor market can lead to a higher rate of unemployment for low-wage workers. 相似文献
45.
Capacity planning is one of the most important elements for an efficient production planning and control system. It is even more important when the main strategies to fulfil sales requirements are make-to-order (MTO) or assemble-to-order (ATO). Neither MTO or ATO companies keep finished products in stock which means that production level is driven by actual sales figures. Therefore, it is very important to have an available capacity as flexible as possible to meet sales requirements. Annualized hours (AH) is a work time control system that helps in increasing the flexibility of available capacity. The main rule of the AH system is to hire employees to work a certain number of hours on a yearly basis. Following some other pre-defined rules and limits, the AH system allows a company to adjust weekly available time in order to reduce idle capacity or to fulfil requirements that could mean overtime. This paper proposes a linear programming model to plan the operations using AH. This model has been implemented in a company that produces agricultural implements, showing that it is very simple to use. It is producing excellent practical results. 相似文献
46.
Approximate Bayesian inference on the basis of summary statistics is well-suited to complex problems for which the likelihood
is either mathematically or computationally intractable. However the methods that use rejection suffer from the curse of dimensionality
when the number of summary statistics is increased. Here we propose a machine-learning approach to the estimation of the posterior
density by introducing two innovations. The new method fits a nonlinear conditional heteroscedastic regression of the parameter
on the summary statistics, and then adaptively improves estimation using importance sampling. The new algorithm is compared
to the state-of-the-art approximate Bayesian methods, and achieves considerable reduction of the computational burden in two
examples of inference in statistical genetics and in a queueing model. 相似文献
47.
Fully nonparametric tests for the independence between random vectors are studied in this paper. The test statistics are functionals of an empirical process defined as the difference between the joint empirical copula and the product of the empirical copulas associated to the vectors that are suspected to be independent. The validity of a weighted bootstrap procedure is established, which allows for a quick computation of p-values. A special attention is given to the asymptotic behavior of the tests under contiguous sequences of distributions. Finally, a characteristic of the copulas in the Archimedean class in terms of independence of vectors is exploited in order to propose a new goodness-of-fit procedure. 相似文献
48.
A path scheme for a game is composed of a path, i.e., a sequence of coalitions that is formed during the coalition formation process and a scheme, i.e., a payoff vector for each coalition in the path. A path scheme is called population monotonic if a player’s payoff does not decrease as the path coalition grows. In this study, we focus on Shapley path schemes of simple
games in which for every path coalition the Shapley value of the associated subgame provides the allocation at hand. Obviously,
each Shapley path scheme of a game is population monotonic if and only if the Shapley allocation scheme of the game is population
monotonic in the sense of Sprumont (Games Econ Behav 2:378–394, 1990). We prove that a simple game allows for population monotonic
Shapley path schemes if and only if the game is balanced. Moreover, the Shapley path scheme of a specific path is population
monotonic if and only if the first winning coalition that is formed along the path contains every minimal winning coalition.
We also show that each Shapley path scheme of a simple game is population monotonic if and only if the set of veto players
of the game is a winning coalition. Extensions of these results to other efficient probabilistic values are discussed. 相似文献
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50.
It is often said that success in today's competitive environment depends on the acquisition and application of sound, relevant knowledge. This paper introduces two management science approaches that have been used for the effective management of knowledge, towards the development of strategy, planning and decision making, in a wide range of organizational settings. Both approaches make use of computer technology to provide a flexible and interactive environment incorporating a visual representation of the problem. The paper briefly describes each approach, together with a case study illustrating its use in practice. A number of common themes relevant to the management of knowledge are identified and discussed. The themes highlight the benefits which arise through the use of computer technology alongside a number of issues relevant to the management of the group process. 相似文献