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41.
Kontkanen  P.  Myllymäki  P.  Silander  T.  Tirri  H.  Grünwald  P. 《Statistics and Computing》2000,10(1):39-54
In this paper we are interested in discrete prediction problems for a decision-theoretic setting, where the task is to compute the predictive distribution for a finite set of possible alternatives. This question is first addressed in a general Bayesian framework, where we consider a set of probability distributions defined by some parametric model class. Given a prior distribution on the model parameters and a set of sample data, one possible approach for determining a predictive distribution is to fix the parameters to the instantiation with the maximum a posteriori probability. A more accurate predictive distribution can be obtained by computing the evidence (marginal likelihood), i.e., the integral over all the individual parameter instantiations. As an alternative to these two approaches, we demonstrate how to use Rissanen's new definition of stochastic complexity for determining predictive distributions, and show how the evidence predictive distribution with Jeffrey's prior approaches the new stochastic complexity predictive distribution in the limit with increasing amount of sample data. To compare the alternative approaches in practice, each of the predictive distributions discussed is instantiated in the Bayesian network model family case. In particular, to determine Jeffrey's prior for this model family, we show how to compute the (expected) Fisher information matrix for a fixed but arbitrary Bayesian network structure. In the empirical part of the paper the predictive distributions are compared by using the simple tree-structured Naive Bayes model, which is used in the experiments for computational reasons. The experimentation with several public domain classification datasets suggest that the evidence approach produces the most accurate predictions in the log-score sense. The evidence-based methods are also quite robust in the sense that they predict surprisingly well even when only a small fraction of the full training set is used.  相似文献   
42.
Urban Ecosystems - Green roofs have recently gained recognition for their potential contribution to urban ecosystems by providing, among other services, habitat for plants and animals, and stepping...  相似文献   
43.
There are times when entire populations of certain countries have had to readjust their lives and economic strategies as all of society is under transition. Post-Soviet Central Asia underwent this period after 1991. During times of transition, there are always people that tend to be able to make use of the new uncertainties, even at the risk of entering legal grey areas. Here new social groups emerge, ethnic origin becomes relevant and new kinship ties are made. These transformation periods are often short and provide limited opportunities for analysing the strategies of those pioneers that I call Kairos economists. They often act only in cooperation with residents of the border and with duty customs and security personnel. This article analyses this special economy with the help of case studies that have been observed during the transformation period from the Soviet to an independent Central Asia.  相似文献   
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The study focuses on dilemmas in storied experiences of everyday after‐school care arrangements among Swedish and Finnish mothers. Finland and Sweden, which share a history of strong labour market attachment among women, arrange institutional after‐school care in similar ways. The data consist of interviews with three Swedish and six Finnish mothers. A positioning analysis of four stories shows how decisions related to children's after‐school hours were allocated among different actors. Two reoccurring dilemmas, Competent‐dependent child stories and Unburdened‐deficient mother stories, emerged from the data analysis as related to prevailing moral discourses on childhood and motherhood.  相似文献   
46.
Transformational leaders are known to inspire and motivate their followers, thereby leading to enhanced job satisfaction. Job satisfaction is an intellectual concept regarding individuals’ attitudes toward their jobs. This study asserts that the underlying mechanisms for transformational leadership to affect employee satisfaction are trust in the community, including the leader (that is, organization) and trust in the self, namely self‐efficacy. Leadership is specifically associated with continual transformations in the higher educational context, and collectivist cultures may manifest different processes underlying the transformational leadership–satisfaction relationship. This study investigated the mediating effects of trust and self‐efficacy on the relationship between transformational leadership and job satisfaction. The study sample included academicians from a nonprofit higher education institution in Turkey. The data were analyzed using structural equation modeling. The results showed that the relationship between transformational leadership and job satisfaction is fully mediated by both trust and self‐efficacy. The mediator effect of trust was shown to be stronger than self‐efficacy, which is assumed to be the result of the cultural context. The results are discussed in the context of employee satisfaction and cultural determinants of employee satisfaction.  相似文献   
47.
Urbanization has been identified as a threat to biodiversity due to landscape modifications. Studies of parasite ecology in urbanized areas lagged behind those made on macro organisms. Here we studied infection prevalence of haemosporidian parasites in an avian community of an urban forest from Germany, and its relationship with bird abundance and body mass. We used PCR to amplify a fragment of the mtDNA cyt b gene to determine the infection status of birds, and bird point counts to determine bird relative abundances. The avifauna was dominated by two small sized insectivore passerines (Parus major, Cyanistes caeruleus), representing ~40 % of the total bird records. The highest haemosporidian prevalence was recorded for Turdus philomelos (100 %) and for Fringilla coelebs (75 %). Bird abundance and body mass were positively associated with infection status for two haemosporidian genera: Plasmodium and Leucocytozoon. Infection rate was lower in juveniles compared to adult birds. We recorded a total of 7 Plasmodium, 26 Haemoproteus, and 10 Leucocytozoon lineages. Avian malaria (P. relictum) was detected infecting 5 individuals of P. major, the most abundant species in the community. These results, together with those of previous studies at the same site, suggest that potentially any of the genetic haemosporidian lineages detected in this urban forest can be transmitted across native and pet bird species, and to species of conservation concern housed at aviaries.  相似文献   
48.
The influence of neoliberalism on culture and subjectivity is well documented. This paper contributes to understanding of how neoliberal ideology enters into the production of subjectivity. While subject formation takes place in multiple and contradictory ways and across multiple social sites, we focus on the increasingly popular media discourse of self-development, and examine it as a technology of neoliberal subjectification. Drawing on Foucauldian understandings, we analyze data from two different newspapers from two different national contexts, both of which are heavily influenced by neoliberalism. Based on our analysis, we detail four interrelated discourses—rationality, autonomy and responsibility, entrepreneurship, and positivity and self-confidence—demonstrating how these discourses constitute the neoliberal subject in ways consonant with neoliberal governmentality. There is no observable resistance to subject positions offered within these discourses. Self-development discourse instills stronger individualism in society, while constraining collective identity, and thus provides social control and contributes to preserving status quo of neoliberal societies.  相似文献   
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This paper explores the effect of teenage childbearing on long-term health outcomes and behaviors of mothers using the Midlife Development in the US dataset. Within-family estimations, using samples of siblings, and twin pairs, are employed to overcome the bias generated by unobserved family background and genetic traits. The results suggest no significant effects on health outcomes, and modest effects on health behaviors, including exercise and preventive care. However, accounting for life-cycle effects demonstrates that teenage childbearing has significant effects on both health outcomes and behaviors early in life, but very few significant effects later in life. Moreover, teenage childbearing has a particularly acute effect among minorities. Finally, this paper provides evidence that the effects operate through reduced income and labor force participation, and matching with a lower “quality” spouse.  相似文献   
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