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Laurent Somme Laura Moquet Muriel Quinet Maryse Vanderplanck Denis Michez Georges Lognay Anne-Laure Jacquemart 《Urban Ecosystems》2016,19(3):1149-1161
Urbanization affects the availability and diversity of floral resources (pollen and/or nectar) for wild pollinating insects. For example, urban green areas are characterized by an abundance of ornamental plant species. Increasingly, trees are planted to improve the aesthetics of urban streets and parks. These urban trees might offer important floral resources to pollinating insects. To examine the suitability of urban trees as resources for pollinating insects, we investigated the chemical composition of pollen and nectar as well as the amount of nectar produced by the nine major insect-pollinated tree species planted in cities of Western Europe, namely Acer pseudoplatanus, Aesculus carnea, A. hippocastanum, Robinia pseudoacacia, Tilia cordata, T. x euchlora, T. x europaea, T. platyphyllos and T. tomentosa. The analyses revealed that globally the Tilia trees provide pollen with lower contents of polypeptides, amino acids and phytosterols compared with the other species. Urban tree flowers offer abundant nectar with relatively high sugar contents (0.16–1.28 mg/flower); sucrose was the predominant sugar in all nectars. The investigated tree species could therefore be considered in future city plantings. 相似文献
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This paper considers how shifts within the social sciences towards conceptualising spatiality in relational terms have unfolded in rural studies in particular ways over the past decade or so. A period in which networks, connections, flows and mobility have all established themselves as compelling conceptual frames for research, the rural has increasingly been recast in relational terms as a multi-authored and multi-faceted space, constituted through local-global interconnections and their place specific, sometimes contested, manifestations. In this way, the multiple meanings of the rural continues to be a focus of critical concern, as are the implications ‘of’ and ‘in’ rural spaces for some of the major issues currently being faced by governments and citizens around the world; including climate change and food security. Apprehending the complexity of the rural in these terms, we argue, requires not only thinking space relationally, but at the same time being epistemologically relational or theoretically pluralist. That is, recognising the co-constituent production of rural space through material and discursive phenomenon, processes and practices, and thus the value of existing theoretical resources (social constructionism, political and economic materialism) in relation with the critical and rigorous appraisal of ‘new’ concepts and ideas to better comprehend rural space in its multidimensional complexity and particularity. To this end, we identify Cindi Katz's notion of ‘countertopography’ as a promising conceptual and methodological addition to the rural scholar's toolkit insofar as it attends to a politics of location and differentation in relation to global processes. We conclude our discussion by sketching out possible objects of countertopographical analysis for understanding ongoing processes of change in rural space(s). 相似文献
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Laura?BiniEmail author Francesco?Dainelli Francesco?Giunta 《Journal of Management and Governance》2017,21(1):63-91
This paper offers a contribution to the call for research on the effectiveness of regulatory interventions governing management commentary disclosure. Specifically, we focus on the mandatory requirement concerning performance indicator disclosure introduced by the Modernisation Directive (2003/51/EC). In keeping with other regulators, the European legislator opted to implement a regulatory approach based on a rule with loose specifications. To understand the effects of this Directive, we have investigated the Italian context, in which neither the national legislator nor the standard setter have supported companies with detailed specifications or guidelines aimed at integrating the European provision. We have compared companies’ disclosure practices before and after the adoption of the Directive, investigating the number of disclosed indicators and also their modalities of presentation, as they are considered essential to guaranteeing the quality of this disclosure. Our results document that a mandatory intervention, even if based on loose specifications, is associated with an increase in disclosure practices. Nevertheless, such regulation does not seem able to guarantee high quality disclosure practices. In fact, before and after the regulation, companies primarily disclose common financial measures. Moreover, the usefulness of such disclosure is undermined by a limited compliance with the international guidelines concerning the modalities of presentation. These results reveal some weaknesses in the European approach to performance indicator regulation. In general, the EU legislator fails to explain the purpose and the objective of performance indicator disclosure and does not take into account the differences between financial and non-financial indicators. Furthermore, it does not provide firms with clear guidelines concerning the presentation modalities. 相似文献
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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
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Martin Webber Mark Hardy Simon Cauvain Aino Kääriäinen Mirja Satka Laura Yliruka 《European Journal of Social Work》2014,17(5):627-640
A controversial proposal to pilot the training of child protection social workers through an intensive work-based route in England is being supported and funded by the UK Government. Frontline, the brainchild of a former teacher, locates social work training within local authorities (‘the agency’) rather than university social work departments (‘the academy’) and has stimulated debate amongst social work academics about their role in shaping the direction of the profession. As a contribution to this debate, this paper explores the duality of social work education, which derives its knowledge from both the academic social sciences and the experience of practice within social work agencies. While social work education has traditionally been delivered by the academy, this paper also explores whether the delivery of training in the allied professions of probation and nursing by ‘the agency’ is equally effective. Finally, this paper explores the Helsinki model which achieves a synergy of ‘academy’ and ‘agency’. It suggests that there are alternative models of social work education, practice and research which avoid dichotomies between the ‘academy’ and the ‘agency’ and enable the profession to be shaped by both social work academics and practitioners. 相似文献
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Increasing family diversity during the past half century has focused national attention on how children are faring in nontraditional family structures. Much of the limited evidence on children in same‐sex couple families suffers from several shortcomings, including a lack of representative data. We use the National Health Interview Survey (2004–2012) and the National Survey of Children's Health (2011–2012) to identify children in different‐sex married and cohabiting families, never and previously married single‐parent families, and same‐sex couple families. Considering important characteristics such as the child's race or ethnicity and adoption status, household socioeconomic standing, family stability, and parent health, we examine the relationship between family type and parent‐rated overall child health. The results suggest that poorer health among children in same‐sex couple as well as different‐sex cohabiting couple and single‐parent families appears to be largely the product of demographic and socioeconomic differences rather than exposure to nontraditional family forms. 相似文献