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排序方式: 共有183条查询结果,搜索用时 15 毫秒
51.
Diane P. Dupont Kevin J. Fox Daniel V. Gordon R. Quentin Grafton 《Journal of Agricultural Economics》2005,56(1):31-57
Regulators in many countries have adopted individual transferable quotas as a means of dealing with the open access problem inherent in fisheries. Using individual vessel data prior to and after the introduction of ITQs in Canada's multi‐species Scotia‐Fundy mobile gear fishery, the paper uses an index number profit decomposition to compare vessel performance over time and across individual vessels. The approach allows us to undertake both an ex post evaluation of short‐term impacts of ITQs and an ex ante evaluation of longer term impacts. With respect to short‐term impacts, the results suggest that larger vessels have benefited the most from the introduction of ITQs, but that all vessels have enjoyed increases in the prices received for those fish species that are included in the quota program. With respect to longer‐term impacts, the transferability provisions of the ITQ program have encouraged exit and more efficient operations to prevail. 相似文献
52.
An Economic Analysis of Targeting Soil Conservation Measures with Respect to Off-site Water Quality 总被引:1,自引:0,他引:1
This paper analyses the advantages and disadvantages of targeting soil conservation measures on the basis of off-site water quality goals. The Stratford Avon watershed in Perth County and the Big Creek watershed in Middlesex County, both located in southwestern Ontario, are used as case studies. Targeting criteria, used as proxies for measuring the contribution to off-farm damage from particular parcels of crop land, are based on the physical characteristics of the parcels. Alternative conservation tillage practices include fall chisel ploughing, ridge planting, no tillage and buffer strips. At each level of the targeting criteria, the reduction in off-farm damage is estimated using the Guelph Model for Evaluating the Effects of Agricultural Management Systems on Erosion and Sedimentation (GAMES). Economic targeting criteria are based on the value of improved water quality under a conservation practice minus the on-farm costs of adoption of that practice. Targeting conservation policies on the basis of reduction of off-farm damages can result in greater efficiency in public policy. The authors conclude that further efforts in targeting conservation policies have the potential to improve the cost effectiveness of soil conservation programs if technical and administrative problems can be overcome. L'article analyse le pour et le contre du ciblage des mesures de conservation des sols sous l'angle de la qualité de l'eau à l'aval. Le bassin versant Stratford Avon dans le comité de Perth et celui de Big Creek dans le comté de Middlesex, tous deux situés dans le sud-ouest de l'Ontario, sont utilisés comme études de cas. Les critères de ciblage utilisés comme valeurs d'approximation dans la détermination de la part des dégâts causés à l'aval qui est attribuable à des parcelles agricoles données, sont basés sur les caractères physiques des parcelles. Les diverses pratiques de travail de conservation comparées sont la labour au chisel, la culture sur billons, la culture sans labour et l'établissement de bandes riveraines. A chaque niveau des critères de ciblage, la réduction des dégâts infligés à l'aval des exploitations est estimée selon le Modèle d'évaluation des effets des systèmes d'exploitation agricole sur l'érosion et la sédimentation de l'Université de Guelph (GAMES). Les critères de ciblage économiques reposent sur la valeur attribuée à l'amélioration de la qualité de l'eau par une pratique de conservation donnée, moins les coûts réels d'adoption de l'exploitant à cette pratique. Le ciblage des politiques de conservation en fonction de la réduction des dégâts causés à l'aval de l'exploitation peut rendre plus efficientes les politiques du secteur public. Il ressort de ces études que les politiques de ciblage des mesures de conservation offrent la possibilité d'améliorer la rentabilité des programmes de conservation du sol, pour autant parvienne à surmonter les problèmes techniques et administratifs. 相似文献
53.
This paper analyzes the costs and benefits of controlling groundwater pollution from agricultural use of nitrogen fertilizer in southwestern Ontario. The Village of Hensall, where nitrate concentrations have been observed above 10 mg/L in recent years, is selected as the study site.'The CREAMS simulation model is used to estimate the effect of reducing nitrogen fertilizer on nitrate leaching and consequently on nitrate groundwater pollution. Estimates of the value of groundwater are obtained from the literature and are used to calculate the off-farm cost of groundwater contamination. This procedure results in a wide range of values for the benefits of reducing nitrate pollution. Estimated annual benefits of improved ground-water quality range from less than $1,000 to more than $30,000 for the village. The off-farm benefits of nitrate groundwater pollution abatement outweigh the cost of using bottled water and also exceed the on-farm cost of reducing nitrogen fertilizer application rates. Placing a tax on nitrogen fertilizer would reduce the level of nitrogen applications, but the farm cost of compliance to a nitrogen tax policy is substantially higher than the compliance cost under a regulatory policy that imposes a quantitative ceiling on nitrogen application rates over the part of the aquifer from which the village draws its water supply. 相似文献
54.
55.
Greg Thomas Glenn Fox George Brinkman Jamie Oxley Ravinderpal Gill Bruce Junkins 《Revue canadienne d'agroeconomie》2001,49(2):153-180
This paper reports a new set of estimates of the returns to swine research in Canada. These estimates are obtained using Agriculture and Agri‐Food Canada's Canadian Regional Agricultural Model (CRAM). Positive Mathematical Programming is incorporated into the model for use in this study. The CRAM allows the effects of supply shifts from technological change in the hog industry to interact with product and factor market conditions in the rest of Canadian agriculture. Extensive sensitivity analysis is conducted to examine the robustness of the return estimates under variations in some of the key assumptions employed in the analysis. The costs of public and private sector swine research are estimated. Public sector research costs are inclusive of the marginal excess burden of taxation. Overall, the estimated benefits from Canadian swine research are high relative to the estimated costs for the time period considered. Previous estimates of the returns to Canadian swine research were obtained by Huot et al. (1989) with a partial equilibrium model that did not allow for intra‐sectoral resource use adjustments. The estimated returns obtained in the present study are generally higher than those obtained by Huot et al. For example, the estimates obtained from the direct application of the econometrically estimated supply function in this study gave an internal rate of return of about 124% and a benefit‐cost ratio of 22.4 to 1. Huot et al reported comparable estimates of about 43% for the internal rate of return and 6–7 to 1 for the benefit‐cost ratio. The differences in returns are not solely attributable to the use of a multi‐market versus a single‐market partial equilibrium approach. There are also differences in the estimates of the marginal excess burden of taxation between the two studies. L'analyse que void présente une nouvelle série d'estimations quant au rendement de la recherche porcine au Canada. Ces estimations dérivent du Modèle d'analyse régionale de l'agriculture du Canada (MARAC) du ministère canadien de l'Agriculture et de l'Agroalimentaire. Aux fins de la présente étude, on avait intégré au modèle une programmation mathématique positive. Le MARAC autorise l'interaction entre les retombées d'une modification de l'offre attribuable au virage technologique de l'industrie porcine et les conditions du marché des produits et des facteurs dans le reste de l'agriculture canadienne. Les auteurs ont effectué une analyse de sensibilité poussée en vue d'établir la robustesse de leurs estimations quand variaient quelques‐unes des principales hypotheses de l'analyse. On a estimé le coût de la recherche sur les pores poursuivie par les secteurs public et privé. Dans le secteur public, le coût de la recherche incluait une charge fiscale légérement excessive. Dans l'ensemble, la recherche sur les porcs entreprise au Canada a rapporté beaucoup comparativement à ce qu'elle a coûté pendant la période à l'étude. Les estimations antérieures, établies par Huot et ses collaborateurs (1989), venaient d'un modèle àéquilibre partiel ne permettant aucun ajustement pour l'utilisation intra‐sectorielle des ressources. Les revenus estimés ici sont généralement plus élevés que ceux de Huot et de ses collaborateurs. Ainsi, une application directe de l'offre estimée par des méthodes économétriques à l'analyse donne un taux de rendement interne d'environ 124 % et un indice de rentabilité de 22,4 pour 1. À titre de comparaison, Huot et ses collaborateurs rapportent des résultats d'environ 43 % pour le taux de rendement interne et de 6 à 7 pour 1 en ce qui concerne l'indice de rentabilité. Pareil écart ne résulte pas uniquement du choix d'un modèle àéquilibre partiel reposant sur plusieurs marchés au lieu d'un seul; on relève aussi des variations dans l'estimation du léger excès de la charge fiscale entre les deux études. 相似文献
56.
Investment tasks include forecasting volatilities and correlations of assets and portfolios. One of the tools widely utilized is stochastic factor analysis on a set of correlated time-series (e.g. asset returns). Published time-series factor models require either sufficiently wide time windows of observed data or numeric solutions by simulations. We developed a ‘variational sequential Bayesian factor analysis’ (VSBFA) algorithm to make online learning of time-varying stochastic factor structure. The VSBFA is an analytic filter to estimate unknown factor scores, factor loadings and residual variances. The covariance matrix of the time-series predicted by the VSBFA can be decomposed into loadings-based covariance and specific variances, and the former can be expressed by ‘explanatory factors’ such as systematic components of various financial market indices. We compared the VSBFA with the most practiced factor model relying on wide data windows, the rolling PCA (principal components analysis), by applying them to 9-year daily returns of 200 simulated stocks with the ‘true’ daily data-generating model completely known, and by using them to forecast volatilities of long-only and long/short global stock portfolios with 25-year monthly returns of more than 800 stocks worldwide. Accuracy of the forecast covariance matrices is measured by a (symmetrized) Kullback–Leibler distance, and accuracy of the forecast portfolio volatilities is measured by bias statistic, log-likelihood, Q-statistic, and portfolio volatility minimization. The factor-based covariance and specific variances predicted by the best VSBFA are significantly more accurate than those by the best rolling PCA. 相似文献
57.
Recently, the National Conference of Commissioners on Uniform State Laws completed a drafting of the Model Employment Termination Act (META). The goal of this suggested state legislation is to end the patchwork of state-defined protections offered to employees who are terminated in at-will work environments. If META provisions are adopted there will be a substantial change in both the protection offered employees and the litigation of wrongful discharge claims within the adopting state. This article presents the changes proposed by META and discusses these changes and their potential implications for employers and employees. 相似文献
58.
59.
Defined contribution pension plans typically rely on some type of lifecycle allocation investment strategy. This approach has recently been shown to be sub-optimal due to the portfolio size effect. The terminal wealth of individuals with steadily increasing earnings over time is significantly less when using a lifecycle strategy compared with a simple contrarian approach. The adverse effect of an inappropriate asset allocation strategy for investors with unorthodox earnings profiles, such as for professional athletes, can be greatly magnified. We demonstrate that strategies that exploit the portfolio size effect vastly dominates terminal wealth earned using lifecycle strategies for individuals who experience unorthodox earning profiles, particularly those generating high investable incomes early in life. While the lifecycle strategy contains some attractive features relating to risk aversion and diminishing utility from wealth, we demonstrate that for unorthodox earnings profiles the case for taking advantage of the portfolio size effect is particularly strong. 相似文献
60.
The economic surplus approach is used to estimate the returns to federal investments in dairy cattle research in Canada. A national supply function is estimated using time series data. Lagged research expenditures are included as explanatory variables in the model, facilitating the calculation of ***marginal as well as average benefits from research. Simulation analysis is used to study the effects of product market distortions associated with Canadian dairy policy as well as of the marginal excess burden on the rates of return to research and on the distribution of research benefits. Returns were found to be high at the margin. Distortions in the product market had a small effect on the overall returns to dairy cattle research but had a large impact on the distribution of research benefits. Rate of return estimates were found to be indicative of underinvestment even when the marginal excess burden was taken into account. 相似文献