Motivated by a breast cancer research program, this paper is concerned with the joint survivor function of multiple event times when their observations are subject to informative censoring caused by a terminating event. We formulate the correlation of the multiple event times together with the time to the terminating event by an Archimedean copula to account for the informative censoring. Adapting the widely used two-stage procedure under a copula model, we propose an easy-to-implement pseudo-likelihood based procedure for estimating the model parameters. The approach yields a new estimator for the marginal distribution of a single event time with semicompeting-risks data. We conduct both asymptotics and simulation studies to examine the proposed approach in consistency, efficiency, and robustness. Data from the breast cancer program are employed to illustrate this research.
Lifetime Data Analysis - Frailty models are generally used to model heterogeneity between the individuals. The distribution of the frailty variable is often assumed to be continuous. However, there... 相似文献
This article contributes to understanding transformational change towards gender equality by examining the transformational change potential of a mentoring programme for women, a type of gender equality intervention both criticized and praised for its ability to bring about change. Drawing upon an empirical case study of a mentoring programme for women academics in a Dutch university, we explore three dimensions of transformational change: organizational members (i) discussing and reflecting upon gendered organizational norms and work practices; (ii) creating new narratives; and (iii) experimenting with new work practices. Our findings indicate five specific conditions that enable transformational change: cross‐mentoring, questioning what is taken for granted, repeating participation and individual stories, facilitating peer support networks and addressing and equipping all participants as change agents. We suggest that these conditions should be taken into account when (re)designing effective organizational gender equality interventions. 相似文献
Suppose that a group of individuals owns collectively a technology which produces a consumption good by means of a (possibly
heterogeneous) input. A sharing rule associates input contributions with a vector of consumptions that are technologically
feasible. We show that the set of allocations obtained by any continuous sharing rule contains Pareto efficient allocations.
We also present a mechanism that implements in Nash equilibrium the Pareto efficient allocations contained in an arbitrary
sharing rule.
Received: 29 June 1998/Accepted: 15 November 2000 相似文献
The authors examined the impact of sense of coherence on the career thought processes of a sample of college students. A. Antonovsky (1987) defined sense of coherence as the global orientation that the world is comprehensible, manageable, and meaningful. Study participants completed the Sense of Coherence Scale (A. Antonovsky, 1987) and the Career Thoughts Inventory (CTI; J. P. Sampson, G. W. Peterson, J. G. Lenz, R. C. Reardon, & D. E. Saunders, 1996). Multivariate tests indicated a medium relationship between sense of coherence and CTI Total and subscale scores; sense of coherence accounted for 14% of the variance. Univariate tests also indicated a medium relationship between sense of coherence and each subscale. 相似文献
A recurring theme across the social sciences is that non‐capitalist production is disappearing albeit slowly and unevenly, and is being replaced by a commodified economy in which goods and services are produced by capitalist firms for a profit under conditions of market exchange. In this paper, however, I evaluate critically this commodification thesis. Even in the heartland of commoditisation ‐ the advanced economies. Large economic spaces are identified where alternative economic relations and motives prevail. Rather than view them as leftovers of pre‐capitalist formations, this paper argues that they are the result of both the contradictions inherent in the structural shifts associated with the pursuit of commodification as well as the existence of‘cultures of resistance’, As such, they are viewed as 'spaces of hope’which highlight the demonstrable construction and practice of alternative social relations and logic's of work outside profit‐motivated market‐oriented exchange. 相似文献
National Park of Tijuca in Rio de Janeiro (Brazil) is about 3,300 ha and considered the largest urban forest in the world. Its floristic composition is typical of Atlantic Rain Forest. The reserve is being altered because of fire occurrences and urban expansion. This study identified locations and causes of forest fires, and makes management recommendations to restore damaged areas. From 1991 to 2000, forest firefighters recorded an average of 75-fire occurrences/year. Identified causes included hot air balloons (24%), intentional (24%), rubbish burning (21%) and religious practices (17%). Primary fuels included invasive grasses and ferns. Although hot air balloons destroyed larger areas of forest in each occurrence, a greater number of fires started in the invasive vegetation along roads that bisect the forest. In response to recurrent forests, invasive vegetation has spread gradually into the forest increasing forest degradation. To decrease fire damage, sites with high fire frequencies and density of invasive vegetation were planted with less flammable species. Results indicate that fire frequency decreased and density of invasive vegetation declined. This approach appears to prevent fire incidence, reduce the need for fire fighting, and preserve existing biodiversity. 相似文献
Service-learning programs are not free from challenges brought about by lack of financial support, lack of widespread commitment from professors, community agencies, and recipients of service, and lack of knowledge and insight in students directly involved in such programs. While service-learning initiatives and programs serve positive functions for organizations and individuals, rhetorical accolades for service learning can distort or omit the realities of program implementation and sustained delivery. This paper specifically explores the following challenges connected to service-learning programs: (1) pedagogical difficulties; (2) student limitations; (3) time constraints; and (4) community cooperation. 相似文献