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21.
When population is increasing, characterizing the optimal water consumption path is complicated by the fact that the underlying dynamics of the water stock is contingent on the level of the stock itself. We propose a method of constructing the optimal path in this case. Since population is increasing, the optimal consumption path may involve refraining at times from consuming the totality of the surface water flow in order to restock in groundwater for future consumption. The aquifer then serves as a means to achieve welfare increasing intertemporal transfers of surface water. Therefore the aquifer itself, as distinct from the stock of water it serves to store, may have value and the marginal valuation of water when groundwater stocks are being drawn upon should, for this reason, differ at times from the marginal valuation of water when it is drawn strictly from surface water.  相似文献   
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This paper examines the legitimacy, viability and efficiency of the European Union Solidarity Fund by asking whether the Fund meets its stated purpose of providing solidarity within the EU, whether it is sufficiently capitalized and if it promotes disaster risk reduction in Europe. In examining these questions, we make use of ADAM models of disaster risks throughout Europe. We conclude that the Solidarity Fund falls short on all three counts, and we suggest possible alternatives. Most far-reaching, we explore whether the EUSF could support insurance systems in Europe by, among other possible activities, capitalizing national public-private insurance programs and providing support for government risk transfer. This would leverage the Fund’s capital and would overcome barriers to the provision of private and public sector insurance in uncertain catastrophe markets. It would also make insurance more affordable to Europe’s most vulnerable communities. Finally, it would reduce the disincentives for risk reduction inherent in post-disaster assistance.  相似文献   
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In 2006, Mexico became the first transition country to transfer part of its public-sector natural catastrophe risk to the international reinsurance and capital markets. The Mexican case is of considerable interest to highly exposed transition and developing countries, many of which are considering similar transactions. Risk financing instruments can assure governments of sufficient post-disaster capital to provide emergency response, disaster relief to the affected population and repair public infrastructure. The costs of financial instruments, however, can greatly exceed expected losses, and for this reason it is important to closely examine their benefits and alternatives. This paper analyzes the Mexican case from the perspective of the risk cedent (the Ministry of Finance and Public Credit), which was informed by analyses provided by the International Institute for Applied Systems Analysis (IIASA). The rationale for a government to insure its contingent liabilities is presented along with the fiscal, legal and institutional context of the Mexican transaction. Using publicly available data, the paper scrutinizes the choice the authorities faced between two different risk-transfer instruments: reinsurance and a catastrophe bond. Making use of IIASA's catastrophe simulation model (CATSIM), this financial risk management decision is analyzed within the context of a public investment decision.  相似文献   
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This paper presents a Business Recovery Assessment Framework (BRAF) to help researchers and practitioners design robust, repeatable, and comparable studies of business recovery in various post‐disruption contexts. Studies assessing business recovery without adequately considering the research aims, recovery definitions, and indicators can produce misleading findings. The BRAF is composed of a series of steps that guide the decisions that researchers need to make to ensure: (i) that recovery is indeed being measured; (ii) that the indicators of recovery that are selected align with the objectives of the study and the definition of recovery; and, where necessary, (iii) that appropriate comparative control variables are in place. The paper draws on a large dataset of business surveys collected following the earthquakes in Canterbury, New Zealand, on 4 September 2010 and 22 February 2011 to demonstrate the varied conclusions that different recovery indicators can produce and to justify the need for a systematic approach to business recovery assessments.  相似文献   
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Participatory irrigation management (PIM) was adopted in Thailand in 2004 to encourage the sustainable use of water in the agricultural sector. The research presented in this paper sought to understand the relationships between public participation, learning, and the implementation of more sustainable water practices through PIM in Thailand. Data was collected through document reviews, observation, informal meetings, and a total of 55 semi‐structured face‐to‐face interviews of local irrigators from two case study regions around the Krasiew Reservoir. Results showed that participating in PIM activities facilitated both instrumental (e.g., water supply and demand data, benefits of on‐time water delivery) and communicative (e.g., reasons for past PIM failure, expectations of fellow farmers) learning among PIM participants. Findings also revealed that social action is fostered through the recognition of human dignity and compassionate communication that instils a sense of ownership and solidarity among irrigators. Sustainable water practices among local farmers were spurred further through learning that the reservoir is a finite water source.  相似文献   
28.
At the regional and continental scale, ecologists have theorized that spatial variation in biodiversity can be interpreted as a response to differences in climate. To test this theory we assumed that ecological constraints associated with current climatic conditions (2000-2004) might best be correlated with tree richness if expressed through satellite-derived measures of gross primary production (GPP), rather than the more commonly used, but less consistently derived, net primary production. To evaluate current patterns in tree diversity across the contiguous United States we acquired information on tree composition from the USDA Forest Service's Forest Inventory and Analysis program that represented more than 17,4000 survey plots. We selected 2693 cells of 1000 km2 within which a sufficient number of plots were available to estimate tree richness per hectare. Our estimates of forest productivity varied from simple vegetation indices indicative of the fraction of light intercepted by canopies at 16-d intervals, a product from the MODIS (Moderate Resolution Imaging Spectro-radiometer), to 8- and 10-d GPP products derived with minimal climatic data (MODIS) and SPOT-Vegetation (Systeme Pour l'Observation de la Terre), to 3-PGS (Physiological Principles Predicting Growth with Satellites), which requires both climate and soil data. Across the contiguous United States, modeled predictions of gross productivity accounted for between 51% and 77% of the recorded spatial variation in tree diversity, which ranged from 2 to 67 species per hectare. When the analyses were concentrated within nine broadly defined ecoregions, predictive relations largely disappeared. Only 3-PGS predictions fit a theorized unimodal function by being able to distinguish highly productive forests in the Pacific Northwest that support lower than expected tree diversity. Other models predicted a continuous steep rise in tree diversity with increasing productivity, and did so with generally better or nearly equal precision with fewer data requirements.  相似文献   
29.
Because American national forests are managed for all citizens, it is important that researchers explore the differences and similarities between citizens living both near and far from publicly managed land. We surveyed residents living at various distances from nationally managed land to collect resident perceptions of different forest fire-management techniques, to determine public preferences for these techniques, and to examine the motivations behind these preferences. Participants both close to and far away from national forests tended to favor a multipronged approach to fire management by preferring the use of a combination of two or more fire-management techniques. There were no significant differences by proximity in participants’ self-rated emotions, types of fire-management techniques preferred, or the reasons and rationales for their preferred fire-management technique(s), indicating that the proximity variable may not be as significant as previously thought.  相似文献   
30.
Nowadays, it is necessary to understand and identify the reactions governing the fate of heavy metals introduced into the environment with low complexing organic compounds, particularly when they are transferred through soils in urban areas. In this work the concomitant influence of pH and acetate on the fate of zinc on siliceous sand was studied in batch and non-saturated column experiments. Total zinc concentrations varied between 2 and 20 mg/l, and total acetate concentrations were fixed at 22, 72, 132, and 223 mM to obtain solution pHs of 4, 5, 6 and 7, respectively. Natural sand (diameter, 0.3-2 mm), mainly constituted of silica, was used. In batch adsorption experiments, zinc adsorption is insignificant at pH 4, low and linear at pH 5, and increasingly nonlinear, of the Langmuir type, at pH 6 and 7 indicating near-saturation conditions of surface sites at these high pH values. In column experiments, Zn retardation increases and the maximum outlet concentration of Zn decreases with rising pH and acetate concentrations. Previous column tracer experiments revealed the occurrence of regionalized water transport in the column. Modeling these data was based on a non-electrostatic approach. Batch and column data modeling was based on the PHREEQC code that allows concomitant resolution of chemical speciation and regionalized water transport. The speciation calculation indicates that the ZnAcetate+ species is the dominant Zn species in the solutions used. Batch experimental curves are correctly modeled assuming the formation of the three surface species triple bond SiOZn+, triple bond SiOH-Zn Acetate+ and triple bond SiO-Zn(Acetate)2-. The column data could be adequately modeled assuming a two-region water transport and the formation of the same three species with the same thermodynamic constants determined in the batch experiments. The hypothesis of the modeling leads to a slight overestimation of the quantities of zinc eluted (10%) at pH 6 and 7, mostly in the desorption phase. These results show that the methodology used facilitates the correct modeling of both batch and transport experiments and formulation of the hypothesis on the interactions between the low reactive sand and a complex solution.  相似文献   
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