There has been much recent work on Bayesian approaches to survival analysis, incorporating features such as flexible baseline hazards, time-dependent covariate effects, and random effects. Some of the proposed methods are quite complicated to implement, and we argue that as good or better results can be obtained via simpler methods. In particular, the normal approximation to the log-gamma distribution yields easy and efficient computational methods in the face of simple multivariate normal priors for baseline log-hazards and time-dependent covariate effects. While the basic method applies to piecewise-constant hazards and covariate effects, it is easy to apply importance sampling to consider smoother functions. 相似文献
This paper outlines four theoretical approaches to the sociology of weapons proliferation: strategic-functional theories, factional theories, geopolitical theories, and institutional theories. Although rarely formulated explicitly, the first three approaches are implicit in the existing literature on proliferation. All three see proliferation as the result of rational decision making, although they differ as to the locus of these decisions, with strategic-functional theories focusing on the nation-state, factional theories on subnational interests, and geopolitical theories on global superpowers. In contrast, the institutional approach disputes the rationality of procurement, arguing instead that weapons purchases are structured and driven by institutionalized normative structures that link advanced weaponry with modernization and sovereignty. The policy implications of this perspective are discussed, and parallels to recent developments in organizational theory are highlighted. 相似文献
Leaders have been argued to play a key role in determining organizational effectiveness across all levels (e.g., individual, team, unit) that exist within organizations. A key component in a leader's ability to be effective within such environments is the degree to which subordinates and co-workers trust him/her. Therefore, it is not surprising that researchers and practitioners alike are interested in identifying the mechanisms through which trust in leadership can be developed as well as those factors which moderate this relationship [e.g., Gillespie, N. A., Mann, L. (2004). Transformational leadership and shared values: The building blocks of trust. Journal of Managerial Psychology, 19, 588–607; Kouzes and Posner, 1995; Roberts, K. H., O'Reilly, C. A. (1974). Failures in upward communication in organizations: Three possible culprits. Academy of Management Journal, 17, 205–215; Whitener, E. M. (1997). The impact of human resource activities on employee trust. Human Resource Management Review, 7, 389–404]. Despite this, research that has addressed the factors that foster trust in leaders and the outcomes of this trust has been disjointed and, as yet, no comprehensive model has been presented to systematically examine these factors. Therefore, the purpose of this article will be to present an integrative model of trust in leadership. 相似文献
The increased risk of violent victimization for adolescents relative to other age groups has recently become a major public health concern. The current study uses data from a multisite study of eighth grade youths attending public schools in 11 cities to determine the extent and nature of youth general and serious violent victimization among both sexes and five racial/ethnic groups in 11 diverse communities. This study explores differences in sex, race/ethnicity, and community independently and explores interactions between sex and community and race/ethnicity and community. Our findings suggest important differences in victimization prevalence and individual victimization rates by sex and community of residence. Racial differences were found to be closely tied to community. Policy implications resulting from our findings are discussed. 相似文献
In this study we systematically map and analyze all disability-related laws and regulations in Israel from 1948 – the year the State of Israel was established – to the present. All 55 laws and 124 regulations (and their amendments) that addressed disability were analyzed via qualitative content analysis; we categorized the legislation into either bio-medical-based policy or rights-based policy. Findings show that most of the legislation reflects the bio-medical approach. Bio-medical-based legislation is being carried out in Israel alongside rights-based legislation even after the enactment of the Equal Rights for Persons with Disabilities Law of 1998. It seems that legislators tend to perceive disability as synonymous to impairment, as a personal tragedy and a medical problem, rather than as a civil rights issue. 相似文献
This quarter's column features a report from the Association of College & Research Libraries (ACRL) Conference, held March 25–28, 2015, in Portland, OR; a couple of reports from the Ohio Valley Group of Technical Services Librarians (OVGTSL) Conference, held May 18–20 in Terre Haute, IN; one report from NASIG, held May 27–30 in Washington, DC; and several reports from the American Library Association (ALA) Annual Conference, held June 25–30 in San Francisco, CA. Topics discussed range from scholarly publishing, copyright and authors’ rights—including as they relate to zines—privacy and analytics, and linked data. 相似文献
This study assesses well-being differences in Bolivia. We specifically investigate whether ethnicity and regional location
explain differences in housing quality, material wealth, sanitation, and educational achievement in Bolivia. We use the 1994
and 1998 DHS surveys of 9114 and 12109 cases, respectively, to test the study hypotheses, which predict that indigenous ethnicity
and highland location negatively affect well-being. Results show that in both surveys, indigenous households had lower levels
of housing quality, material wealth, and sanitation as compared to non-indigenous households. Indigenous heads of household
also showed lower levels of education as compared to non-indigenous heads of household. Households located in the highlands
showed lower levels of housing quality and sanitation in both 1994 and 1998. Highland location was a significant predictor
of material wealth in the 1998 model but not in the 1994 one. Highland location was not a significant predictor of education
in either the 1994 or 1998 models. Rural–urban location had the largest influence on well-being. 相似文献
The 2020 hurricane season threatened millions of Americans concurrently grappling with COVID-19. Processes guiding individual-level mitigation for these conceptually distinct threats, one novel and chronic (COVID-19), the other familiar and episodic (hurricanes), are unknown. Theories of health protective behaviors suggest that inputs from external stimuli (e.g., traditional and social media) lead to threat processing, including perceived efficacy (self- and response) and perceived threat (susceptibility and severity), guiding mitigation behavior. We surveyed a representative sample of Florida and Texas residents (N = 1846) between April 14, 2020 and April 27, 2020; many had previous hurricane exposure; all were previously assessed between September 8, 2017 and September 11, 2017. Using preregistered analyses, two generalized structural equation models tested direct and indirect effects of media exposure (traditional media, social media) on self-reported (1) COVID-19 mitigation (handwashing, mask-wearing, social distancing) and (2) hurricane mitigation (preparation behaviors), as mediated through perceived efficacy (self- and response) and perceived threat (susceptibility and severity). Self-efficacy and response efficacy were associated with social distancing (p = .002), handwashing, mask-wearing, and hurricane preparation (ps < 0.001). Perceived susceptibility was positively associated with social distancing (p = 0.017) and hurricane preparation (p < 0.001). Perceived severity was positively associated with social distancing (p < 0.001). Traditional media exhibited indirect effects on COVID-19 mitigation through increased response efficacy (ps < 0.05), and to a lesser extent self-efficacy (p < 0.05), and on hurricane preparation through increased self-efficacy and response efficacy and perceived susceptibility (ps < 0.05). Social media did not exhibit indirect effects on COVID-19 or hurricane mitigation. Communications targeting efficacy and susceptibility may encourage mitigation behavior; research should explore how social media campaigns can more effectively target threat processing, guiding protective actions. 相似文献
This paper studies the single machine scheduling problem with availability constraints and optional job rejection. We consider the non-resumable and resumable variants, and show that the problems remain ordinary NP-hard, even with the rejection possibility extension, by presenting pseudo-polynomial dynamic-programming (DP) solutions. We also present an enhanced running time implementation of the algorithm of Kellerer and Strusevich (Algorithmica 57(4):769–795, 2010) for the resumable scenario without job rejection. This solution is adapted to efficiently solve the machine non-availability problem with a floating interval and the problem of two competing agents on a single machine, with and without optional job rejection. Numerical experiments support the efficiency of our DP implementation.