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281.
In the last 10 years, research devoted to the construct of leader–member exchange (LMX) has increasingly relied on the tenets of social exchange as a theoretical foundation to propose and test relationships between supervisor‐subordinate dyads and variables of significant consequence. Despite the theory underpinning such relationships, researchers continue to measure LMX with scales developed to assess vertical dyad linkage (VDL), not social exchange. To address this concern, we investigated the content validity of LMX7 (the most widely cited measure of LMX) and LMX‐MDM (a popular multidimensional measure of LMX). Findings from content validity assessments by 25 LMX experts revealed LMX7 and LMX‐MDM items are not representative of the construct of social exchange. As such, we undertook a series of studies to develop a new scale we label, leader–member social exchange (LMSX). Results indicate LMSX is able to assess different, as well as the same, components of the supervisor–subordinate relationship as previous scales while being more theoretically consistent with the notion of social exchange. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   
282.
South Africa has developed niche competencies around the extraction and processing of mineral resources. Firms involved in the manufacture and supply of inputs to mining and mineral processing represent a key source of competitive advantage upon which future growth and development in the country can be planned. Drawing on a qualitative and quantitative study of 678 supplier firms conducted in 2004, this paper presents an assessment of the state of the South African minerals inputs cluster. The various demand and supply relationships, dynamics, and growth opportunities within the cluster are highlighted and the threats affecting the cluster's future competitiveness reviewed. The interventions needed to overcome and/or enhance them are also identified.  相似文献   
283.
Social capacity building for natural hazards is a topic increasingly gaining relevance not only for so-called developing countries but also for European welfare states which are continuously challenged by the social, economic and ecological impacts of natural hazards. Following an outline of recent governance changes with regard to natural hazards, we develop a heuristic model of social capacity building by taking into account a wide range of existing expertise from different fields of research. Particular attention is paid to social vulnerability and its assessment, as well as to risk communication and risk education as specific strategies of social capacity building. We propose to distinguish between interventionist and participatory approaches, thus enabling for a better understanding of existing practices of social capacity building as well as their particular strengths and weaknesses. By way of conclusion, we encourage more research on social capacity building for natural hazards in the European context which at present is highly diverse and, at least in parts, only poorly investigated.  相似文献   
284.
In recent years, as the implementation and use of Non-Invasive Prenatal Testing (NIPT) have increased, the cost of the test has been decreasing. The cost of NIPT is expected to fall further in the upcoming years. As a result of the decreasing cost of NIPT, many jurisdictions may change their prenatal screening policies toward abandoning serum-based screening and instead, implement and support NIPT as the first-tier screening for all women. There are several concerns in replacing first-trimester screening with NIPT. In this scoping review, we aimed to map the existing knowledge about possible issues in the systematic implementation of NIPT as the primary method of first-tier screening and to assess if any jurisdiction has altered its policy and discontinued serum-based prenatal screening in exchange for NIPT. The Medline database (Ovid) and Google Scholar was searched and all the studies discussing, investigating, or reporting on the systematic implementation of NIPT as the primary method of first-tier screening were included. All the studies went through a two-stage screening process and included full-text articles were reviewed. We did not find any articles indicating a country or region that replaced traditional prenatal screening by NIPT. The included articles were charted, and the data about the possible issues in the systematic implementation of NIPT as the primary method of first-tier screening are summarized narratively and presented in tables in four categories. The findings of this scoping review may be informative for stakeholders and policymakers regarding recent changes in NIPT implementation policies around the world and may aid with developing policy for NIPT implementation with a broader perspective.  相似文献   
285.
Water resources and land use are closely linked with each other and with regional climate, assembling a very complex system. The understanding of the interconnecting relations involved in this system is an essential step for elaborating public policies that can effectively lead to the sustainable use of water resources. In this study, an integrated modelling framework was assembled in order to investigate potential impacts of agricultural expansion and climate changes on Irrigation Water Requirements (IWR) in the Taita Hills, Kenya. The framework comprised a land use change simulation model, a reference evapotranspiration model and synthetic precipitation datasets generated through a Monte Carlo simulation. In order to generate plausible climate change scenarios, outputs from General Climate Models were used as reference to perturbing the Monte Carlo simulations. The results indicate that throughout the next 20 years the low availability of arable lands in the hills will drive agricultural expansion to areas with higher IWR in the foothills. If current trends persist, agricultural areas will occupy roughly 60% of the study area by 2030. This expansion will increase by approximately 40% the annual water volume necessary for irrigation. Climate change may slightly decrease crops' IWR in April and November by 2030, while in May a small increase will likely be observed. The integrated assessment of these environmental changes allowed a clear identification of priority regions for land use allocation policies and water resources management.  相似文献   
286.
Book reviews     
Making Cities Work: the role of local government in the urban environment. Richard Gilbert, Don Stevenson, Herbert Girardet &; Richard Stren, 1996, London, Earthscan, 203pp. ISBN 1 85383 354 1, £13.95 pbk

Environmental Policy in an International Context, Vols 1–3: Perspectives, Conflicts and Prospects. P. Glasbergen &; A. Blowers (Series Eds) London, Arnold

Rhetoric and Reality in Environmental Policy. M. Wintle &; R. Reeve (Eds), 1994, Aldershot, Avebury Studies in Green Research, 154 pp. ISBN 1 85628 927 3

FutureNatural: Nature, Science, Culture. G. Roberston et al. (Eds) 1996, London, Routledge, ISBN 0415 070139, £40.00 hbk

Environmental Policy with Political Integration: the European Union and the United States. New horizons in environmental economics. John B. Braden, Henk Folmer &; Thomas S. Ulen (Eds), 1996, Cheltenham, Elgar Publishing, 477 pp. ISBN 1 85898 217 0  相似文献   
287.
This article examines the opportunities for fostering sustainable development through public sector sourcing from small- and medium-sized enterprises (SMEs). Buying from small businesses can make such contributions in a variety of forms, ranging from a contribution to local economic development through providing innovative green products and services, particularly in the food sector, to helping the public sector organisation to better align its operations with its community. Sourcing from small businesses also has implications for the governance of sourcing processes and can benefit from a partnership approach. Barriers to public sector sourcing from small businesses are discussed and suggestions made on how these can be overcome.  相似文献   
288.
Using interdisciplinary field research in the Usa Basin, northeast European Russia, we compared local inhabitants' perception of environmental problems with chemical and remote-sensing signatures of environmental pollution and their local impacts. Extensive coal mining since the 1930s around Inta and Vorkuta has left a legacy of pollution, detected by measuring snowpack, topsoil, and lichen chemistry, together with remote-sensing techniques and analysis of lake water and sediments. Vorkuta and its environs suffered the worst impacts, with significant metal loading and alkalization in lakes and topsoils, elevated metals and cations in terricolous (reindeer) lichens, and changes in vegetation communities. Although the coal industry has declined recently, the area boasts a booming oil and gas industry, based around Usinsk. Local perceptions and concerns of environmental pollution and protection were higher in Usinsk, as a result of increased awareness after a major oil spill in 1994, compared with Vorkuta's inhabitants, who perceived air pollution as the primary environmental threat. Our studies indicate that the principal sources of atmospheric emissions and local deposition within 25 to 40 km of Vorkuta were coal combustion from power and heating plants, coal mines, and a cement factory. Local people evaluated air pollution from direct observations and personal experiences, such as discoloration of snow and respiratory problems, whereas scientific knowledge played a minor role in shaping these perceptions.  相似文献   
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