The Rio Mannu River Basin (Sardinia, Italy) is undergoing a process of agricultural intensification. Like many Mediterranean areas, this basin is characterized by water shortages and diffuse pollution from agricultural sources. Hence the objective of this study was to develop possible land use and land management scenarios that could constitute an alternative to the current watershed management. Several land use and land management scenarios were formulated and analyzed with local stakeholders, and two were selected and simulated as realistic in consideration of the socio-economical aspects of the study area. Scenario 1 involves agricultural practices that include a reduction in fertilizer use to meet the Water Framework Directive requirements for “good” status of water bodies. Scenario 2 introduces rapeseed cultivation, replacing durum wheat in a small area, to investigate the impact of biofuel plant cultivation on water quality. Each option was assessed by considering the effects on water quality, crop yields and economic benefits. The Soil and Water Assessment Tool (SWAT) model was applied to simulate hydrological processes and evaluate current and future nutrient loads. This model requires adequate streamflow data for calibration and validation. However, as is the case for many Mediterranean basins, insufficient data were available. Therefore, a methodology was developed and tested to calibrate hydrological processes based on the transposition of a parameter set from a gauged catchment located in the same region. This study suggests that a sound use of fertilizers could substantially reduce the amount of nutrients flowing into surface waters, although the effects of such a policy on crop yield and farm income would be negative in some cases. Moreover, the results clearly predict that the replacement of durum wheat with rapeseed (a biofuel crop), could offer a margin of profit, but would have a negative impact on water quality due to increased nutrient losses. Consequently, this option is unsuitable for this area. Furthermore, it can be inferred from these results that the promotion of the use of energy from renewable sources may have a negative impact on the objectives of the EU Water Framework Directive. Clearly, this process needs to be regulated, taking into account environmental and socio-economical aspects. 相似文献
Prior research on adverse selection in health insurance markets has found only mixed evidence for adverse selection in group settings. We examine the impact of state community rating regulations enacted in the 1990s, which greatly limited insurers' ability to risk rate premiums, to determine if adverse selection is more evident in non-group insurance markets. Using data from large, national surveys we find evidence of a shift to a less healthy pool of non-group enrollees as a consequence of community rating. Community rating made healthy people 20 to 60% less likely to be insured by non-group health insurance; in addition, we found evidence that young and healthy people were 20 to 30% more likely to be uninsured as a result of community rating. We also find evidence that individuals in poor health were 35 to 50% more likely to be insured in the non-group market, but only limited evidence suggesting that persons in poor health were less likely to be uninsured. Our results are further supported by findings suggesting that non-group enrollees were sicker as a result of the community rating laws. Lastly, we find evidence suggesting that HMO penetration in the non-group market increased disproportionately in states that implemented community rating relative to states that did not. 相似文献
Summary. Traditional analysis of auctions assumes that each bidder's beliefs about opponents' valuations are represented by a probability
measure. Motivated by experimental findings such as the Ellsberg Paradox, this paper examines the consequences of relaxing
this assumption in the first and second price sealed bid auctions with independent private values. The multiple priors model
of Gilboa and Schmeidler [Journal of Mathematical Economics, 18 (1989), 141–153] is adopted specifically to represent the bidders' (and the auctioneer's) preferences. The unique equilibrium
bidding strategy in the first price auction is derived. Moreover, under an interesting parametric specialization of the model,
it is shown that the first price auction Pareto dominates the second price auction.
Received: December 15, 1995; revised version: February 19, 1997 相似文献
Summary. Suppose there is a finite set of acts defined on a finite state space and a decision maker chooses an act from the set. In
this setting, the subjective expected utility model is observationally indistinguishable from all models of preference that
satisfy Savage's axiom P3. The result has implications also for rationalizability in strategic games.
Received: September 18, 1998; revised version: January 29, 1999 相似文献
Nowadays network is the preferred governance form to conduct economic transactions. Network solution allows to reach flexibility maintaining cost and quality level. Since network concept refers to a great variety of organizational hybrids it is possible to choose the one that fits better market requirements. The new trends in inter-organization relationships push towards network solutions: companies are interested in relationships with partners and customers to overcome resource dependence, to enter too risky market or simply differentiate their business portfolio. The proposed research focuses on the network concept aiming at highlighting threats and opportunities to investigate the double nature of the risk concept. Network structures offer flexibility and higher profit as a consequence and business risk sharing opportunity.These two aspects (profit and risk) are strictly related and have to be considered together to depict a complete scenario; this implies that risk assessment and management in network environment cannot neglect profit sharing or, in other words, that profit sharing mechanisms should use risk as driver. In this context our research proposes a methodology to measure risk taking into account network peculiarities; risk estimation is a basic step to evaluate the opportunity cost of capital needed to compute the network Net Present Value (NPV) that is assumed as base in the profit sharing process. The profit sharing process has been tackled using the Shapley value approach that is inspired to the fairness principle while the opportunity cost of capital is assessed using the Capital Asset Pricing Model (CAPM). 相似文献
Engineering is a practical discipline, dedicated to the solution of problems through the sound application of principles derived from the natural sciences and mathematics. Engineering pedagogy has therefore to balance the need for learners to gain a deep understanding of the theoretical basis of the problem domain whilst grasping its practical implications. However, little is known as to the most effective sequence of delivery: is it better to begin with theory and build up to practice or vice versa? Here, we present the idea of testing this through a carefully designed pedagogical experiment. We begin by discussing the issues around the creation of a pedagogical experiment to answer such a question, and define the nature and scope of such experiments. We then create a formal framework within which such questions can be tested and present an experiment in the domain of architectural engineering that pilots this new approach. Finally, we discuss the utility of using such a framework to lead evidence-based discussions of pedagogical practice within the engineering education literature, and conclude that similar experiments could be, and should be, completed by other teams wanting to examine delivery order or other binary choice situations.
The canonical approach to analyse the poverty impact of growth is based on the comparison of poverty before and after growth. Measurement tools endorsing this approach fail to capture the different experiences of poverty dynamic in the population: there can be groups of the population made poorer or non‐poor made poor by growth. We propose an approach that allows measuring this individual poverty incidence of growth and show how it is related with existing models. We apply our framework to evaluate the poverty impact of growth in Indonesia, by comparing the 1993–2000 with the 2000–07 and 2007–14 growth spells. 相似文献