937 resultados para agricultural shows


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The general focus of this paper is the regional estimation of marginal benefits of targeted water pollution abatement to instream uses. Benefit estimates are derived from actual consumer choices of recreational fishing activities and the implied expenditures for various levels of water quality. The methodology is applied to measuring the benefits accruing to recreational anglers in Indiana from the abatement of pollutants that are by-products of agricultural crop production.

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This article shows how the solution to the promotion problem—the problem of locating the optimal level of advertising in a downstream market—can be derived simply, empirically, and robustly through the application of some simple calculus and Bayesian econometrics. We derive the complete distribution of the level of promotion that maximizes producer surplus and generate recommendations about patterns as well as levels of expenditure that increase net returns. The theory and methods are applied to quarterly series (1978:2S1988:4) on red meats promotion by the Australian Meat and Live-Stock Corporation. A slightly different pattern of expenditure would have profited lamb producers

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Attribute non-attendance in choice experiments affects WTP estimates and therefore the validity of the method. A recent strand of literature uses attenuated estimates of marginal utilities of ignored attributes. Following this approach, we propose a generalisation of the mixed logit model whereby the distribution of marginal utility coefficients of a stated non-attender has a potentially lower mean and lower variance than those of a stated attender. Model comparison shows that our shrinkage approach fits the data better and produces more reliable WTP estimates. We further find that while reliability of stated attribute non-attendance increases in successive choice experiments, it does not increase when respondents report having ignored the same attribute twice.

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Bowen and colleagues’ methods and conclusions raise concerns.1 At best, the trial evaluates the variability in current practice. In no way is it a robust test of treatment. Two communication impairments (aphasia and dysarthria) were included. In the post-acute stage spontaneous recovery is highly unpredictable, and changes in the profile of impairment during this time are common.2 Both impairments manifest in different forms,3 which may be more or less responsive to treatment. A third kind of impairment, apraxia of speech, was not excluded but was not targeted in therapy. All three impairments can and do co-occur. Whether randomised controlled trial designs can effectively cope with such complex disorders has been discussed elsewhere.4 Treatment was defined within terms of current practice but was unconstrained. Therefore, the treatment group would have received a variety of therapeutic approaches and protocols, some of which may indeed be ineffective. Only 53% of the contact time with a speech and language therapist was direct (one to one), the rest was impairment based therapy. In contrast, all of the visitors’ time was direct contact, usually in conversation. In both groups, the frequency and length of contact time varied. We already know that the transfer from impairment based therapy to functional communication can be limited and varies across individuals.5 However, it is not possible to conclude from this trial that one to one impairment based therapy should be replaced. For that, a well defined impairment therapy protocol must be directly compared with a similarly well defined functional communication therapy, with an attention control.

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This chapter explores some of the implications of adopting a research approach that focuses on people and their livelihoods in the rice-wheat system of the Indo-Gangetic Plains. We draw on information from a study undertaken by the authors in Bangladesh and then consider the transferability of our findings to other situations. We conclude that if our research is to bridge the researcher-farmer interface, ongoing technical research must be supported by research that explores how institutional, policy, and communication strategies determine livelihood outcomes. The challenge that now faces researchers is to move beyond their involvement in participatory research to understand how to facilitate a process in which they provide information and products for others to test. Building capacity at various levels for openness in sharing information and products–seeing research as a public good for all–seems to be a prerequisite for more effective dissemination of the available information and technologies.

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Developing models to predict the effects of social and economic change on agricultural landscapes is an important challenge. Model development often involves making decisions about which aspects of the system require detailed description and which are reasonably insensitive to the assumptions. However, important components of the system are often left out because parameter estimates are unavailable. In particular, measurements of the relative influence of different objectives, such as risk, environmental management, on farmer decision making, have proven difficult to quantify. We describe a model that can make predictions of land use on the basis of profit alone or with the inclusion of explicit additional objectives. Importantly, our model is specifically designed to use parameter estimates for additional objectives obtained via farmer interviews. By statistically comparing the outputs of this model with a large farm-level land-use data set, we show that cropping patterns in the United Kingdom contain a significant contribution from farmer’s preference for objectives other than profit. In particular, we found that risk aversion had an effect on the accuracy of model predictions, whereas preference for a particular number of crops grown was less important. While nonprofit objectives have frequently been identified as factors in farmers’ decision making, our results take this analysis further by demonstrating the relationship between these preferences and actual cropping patterns.

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The process of global deforestation calls for urgent attention, particularly in South America where deforestation rates have failed to decline over the past 20 years. The main direct cause of deforestation is land conversion to agriculture. We combine data from the FAO and the World Bank for six tropical Southern American countries over the period 1970–2006, estimate a panel data model accounting for various determinants of agricultural land expansion and derive elasticities to quantify the effect of the different independent variables. We investigate whether agricultural intensification, in conjunction with governance factors, has been promoting agricultural expansion, leading to a ‘‘Jevons paradox’’. The paradox occurs if an increase in the productivity of one factor (here agricultural land) leads to its increased, rather than decreased, utilization. We find that for high values of our governance indicators a Jevons paradox exists even for moderate levels of agricultural productivity, leading to an overall expansion of agricultural area. Agricultural expansion is also positively related to the level of service on external debt and population growth, while its association with agricultural exports is only moderate. Finally, we find no evidence of an environmental Kuznets curve, as agricultural area is ultimately positively correlated to per-capita income levels.

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We report an atomic resolution X-ray crystal structure containing both enantiomers of rac-[Ru(phen)2dppz]2+ with the d-(ATGCAT)2 DNA duplex (phen = phenanthroline; dppz = dipyridophenazine). The first example of any enantiomeric pair crystallized with a DNA duplex shows different orientations of the Λ and Δ binding sites, separated by a clearly defined structured water monolayer. Job plots show that the same species is present in solution. Each enantiomer is bound at a TG/CA step and shows intercalation from the minor groove. One water molecule is directly located on one phenazine N atom in the Δ-enantiomer only.