Gerontocracy, in its narrowest sense, refers to political systems ruled by elderly people, whether de jure or de facto. Although formal gerontocratic rules are progressively disappearing, contemporary political systems are still governed by individuals who are significantly older than the mean voter. This article reviews existing explanations for the prevalence of gerontocracy. To summarize main findings, gerontocracy cannot be explained by the leadership qualities of older rulers: aging leaders do not perform better in office and voters seem to be aware of it. Instead, existing research suggests that gerontocracy can be explained by strategic considerations. In autocracies, the selectorate tends to choose aging leaders in order to reduce their expected tenure length. In democracies, voters are more likely to select experienced candidates, which they expect to be more effective at advancing the interests of their constituency: this premium put on experience mechanically lengthens political careers and increases the age of the average politician. Finally, older voters, which participate more in politics, tend to prefer older politicians, because they (correctly) expect them to better defend their own interests. 相似文献
Urban areas consist of wide expanses of impervious surfaces which are known to negatively affect insect biodiversity in general, but green spaces within cities have the potential to provide necessary habitat and foraging resources. Although, communal gardens were primarily intended to provide fresh, regional food to denizens, these green islands also host a surprisingly high number of wild bee species.
The gardens were characterized based on structural elements such as flower frequency, the relative percentage of lawn, trees, shrubs, planted crops and infrastructure (e.g. seating possibilities or garden houses). Further, the effects of different landscape structures surrounding the gardens and distance to the city center were analyzed on the total wild bee species richness and functional traits. Focusing on these putative influencing factors, statistical analyses calculating random decision forests along with generalized linear mixed models were applied. With 113 observed wild bee species, communal gardens provide habitat for a quarter of all known species in Vienna. In conclusion, results revealed that only elements within the gardens had an effect on species richness, with flower frequency as the major positive driver. The examined communal gardens promote and conserve wild bees independent from the location within the city or garden size. Furthermore, these green patches are important sanctuaries, hosting rare and threatened species as well as remarkably special wild bee communities.
A dynamic coupled modelling is investigated to take temperature into account in the individual energy consumption forecasting. The objective is both to avoid the inherent complexity of exhaustive SARIMAX models and to take advantage of the usual linear relation between energy consumption and temperature for thermosensitive customers. We first recall some issues related to individual load curves forecasting. Then, we propose and study the properties of a dynamic coupled modelling taking temperature into account as an exogenous contribution and its application to the intraday prediction of energy consumption. Finally, these theoretical results are illustrated on a real individual load curve. The authors discuss the relevance of such an approach and anticipate that it could form a substantial alternative to the commonly used methods for energy consumption forecasting of individual customers. 相似文献
The Monte Carlo (MC) simulation approach is traditionally used in food safety risk assessment to study quantitative microbial risk assessment (QMRA) models. When experimental data are available, performing Bayesian inference is a good alternative approach that allows backward calculation in a stochastic QMRA model to update the experts’ knowledge about the microbial dynamics of a given food‐borne pathogen. In this article, we propose a complex example where Bayesian inference is applied to a high‐dimensional second‐order QMRA model. The case study is a farm‐to‐fork QMRA model considering genetic diversity of Bacillus cereus in a cooked, pasteurized, and chilled courgette purée. Experimental data are Bacillus cereus concentrations measured in packages of courgette purées stored at different time‐temperature profiles after pasteurization. To perform a Bayesian inference, we first built an augmented Bayesian network by linking a second‐order QMRA model to the available contamination data. We then ran a Markov chain Monte Carlo (MCMC) algorithm to update all the unknown concentrations and unknown quantities of the augmented model. About 25% of the prior beliefs are strongly updated, leading to a reduction in uncertainty. Some updates interestingly question the QMRA model. 相似文献
Communicating and engaging with children is a foundational component of child care social work practice, but all too frequently, in the wake of serious incidents, it is the focus of criticism. Drawing on findings from a large‐scale ESRC‐funded research project conducted in the four U.K. nations, this paper explores, through a psychosocial analytic lens, how social workers anticipate, enact and reflect on their encounters with both children and their families. Close analysis of what social workers said about their practice alongside what they were observed to do in practice revealed perceptions, patterns and processes of communication that, first, minimize emotions and the complexity of the professional task and second, overly privilege verbal interaction. Drawing on Sennett's (2012) ideas this paper offers a reconceptualisation of this professional task, from a communicative to a co‐operative one. It affords and creates a space in which social workers can develop more attuned communicative practices that include rituals, gestures and the minimal use of force. The theoretical insights and evidence‐informed practice recommendations arising from this research have conceptual significance for the social work discipline and practical significance for the child care social work profession, across national and international contexts. 相似文献
Green roofs are potentially valuable habitats for plants and animals in urban areas. Wild bees are important pollinators for crops and wild plants and may be enhanced by anthropogenic structures, but little is known about wild bees on green roofs in cities. This study investigates the effects of green roof qualities (floral resources, substrate character and depth, roof height and age) on wild bee diversity, abundance and traits (nesting type, sociality, pollen specialisation, body size) on green roofs in Vienna. Nine green roofs were sampled monthly between March and September 2014 by a semi quantitative approach. Wild bees were collected in pre-defined sub-areas for the same amount of time and floral resources were recorded. Over all green roofs, 992 individuals belonging to 90 wild bee species were observed. Wild bee diversity and abundance was strongly positively affected by increasing forage availability and fine substrates. Wild bees on roofs were characteristically solitary, polylectic and 8.3–11.2 mm. Regarding nesting type, the percentage of above-ground nesting bees was higher compared to the common species composition in Middle Europe. Ground-nesting wild bees were mainly eusocial, smaller (6.4–9.6 mm) and positively affected by roofs with fine substrates. During June, when forage availability by wildflowers on roofs was “low” (5–15% flower coverage), flowering Sedum species were an important forage resource. We conclude that wild bee diversity and abundance on green roofs are enhanced by floral resources. Furthermore, the installations of areas with finer and deeper substrates benefit ground nesting and eusocial wild bees. 相似文献
This article is based on a current research, combining quantitative (human resources figures and statistics) and qualitative data (60 interviews with career managers, top managers and high potential talents, both men and women), conducted in a major French utility company on the subject of diversity and more specifically on the issue of women's access to top management positions. The main purpose of this research is to understand the difficulties women may encounter in the course of their occupational career linked to organizational aspects, including the ‘glass ceiling’ processes, informal norms related to management positions (such as time and mobility constraints) and social and cultural representations attached to leadership. The other perspective of this research focuses on the different strategies women and men build either to conform to the organizational norms or bypass them. The issue of work–life balance are therefore addressed both from a corporate/organizational standpoint and an individual and family perspective. 相似文献