1,389 research outputs found


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    The South Pacific is home to the world's largest and most valuable tuna fishery. Despite this, the Pacific island countries have found it tremendously difficult to capture significant economic rents from the resource. It is argued in this paper that poor economic policy partly explains this. However, poor policies are preventing the implementation of strong, cost-effective institutions for the governance of the fishery which, coupled with strong institutions for broad social and economic governance, are required for development of the industry. Opportunities for policy reform that is likely to lead to significant gains from the fishery are highlighted.Resource /Energy Economics and Policy,

    The role of expected protein levels in determining the impact of protein premiums and discounts: a note

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    Fraser (1997) considered the impact of protein premiums and discounts on a grower’s income stream and willingness‐to‐pay for a forward contract where the protein premium and discount system is centred on a grower’s existing expected protein level. This article extends these results to consider the impact of a protein premium and discount system which is not centred on a grower’s existing expected protein level. The article suggests that the grower’s existing expected protein level plays a crucial role in determining the impact of the system.Crop Production/Industries,

    The impact of price and yield risk on the bioeconomics of reservoir aquaculture in north Vietnam

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    A bioeconomic model of reservoir aquaculture in northern Vietnam is used to investigate the impacts of price and yield risk on the level, variability and skewness of expected net revenue and utility. Prices and yields are assumed to follow lognormal and beta distributions, respectively. Net revenue follows a generalized gamma distribution and is found to be very risky compared with similar enterprises elsewhere, mainly due to the relatively high yield risk. This represents the nascent nature of the industry in Vietnam and the opportunity for efficiency improvements. Increasing production capacity (through increasing reservoir size, stocking density, production cycle length and harvest rate) are found to increase profits and decrease the variability of profits. Species diversification was found to reduce the riskiness of the enterprise.bioeconomic modelling, price risk, yield risk, aquaculture, Vietnam, Resource /Energy Economics and Policy,


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    The tuna resources of the Western and Central Pacific are the world's largest and most valuable fisheries of their type and are of significant economic importance to the Pacific island countries through whose waters they migrate. Two major concerns exist with the current governance of this fishery. First, Pacific island countries receive only a small share of the resource rents from the tuna fisheries. Second, the current management structure of the fisheries will not ensure the long-term sustainability of the resources. This paper derives a model to show that the sustainability of the resource can be improved when a single policymaker acts as Stackelberg leader and sets a tax, or an equivalent quantity instrument, to maximize rents from the resource. A practical institutional mechanism is presented that mimics the model's rent maximization outcome and that offers substantial benefits to both Pacific island countries and distant water fishing nations.Resource /Energy Economics and Policy,

    Finding Nemo: estimating import demand for live reef food fish

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    Reef fish traded alive for table food are high value-to-volume products, with demand centred in Hong Kong and southern mainland China. Import demand functions for live reef food fish are estimated for Hong Kong, in aggregate and for individual fish species. Cross-price, income and population elasticities, and the impact of SARS and Chinese New Year on demand, are estimated. Results show that price has a smaller influence on import demand than expected. The most influential factor is Chinese New Year. The price of low and medium-value species exhibited a negative impact, whereas the price of very high-value species exhibited a positive impact, on demand. This suggests that high-value live reef species may be Veblen goods, where consumption increases as a direct function of its price, in this case due to associated prestige and status

    Effects of an Advocacy Trial on Food Industry Salt Reduction Efforts—An Interim Process Evaluation

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    The decisions made by food companies are a potent factor shaping the nutritional quality of the food supply. A number of non-governmental organizations (NGOs) advocate for corporate action to reduce salt levels in foods, but few data define the effectiveness of advocacy. This present report describes the process evaluation of an advocacy intervention delivered by one Australian NGO directly to food companies to reduce the salt content of processed foods. Food companies were randomly assigned to intervention (n = 22) or control (n = 23) groups. Intervention group companies were exposed to pre-planned and opportunistic communications, and control companies to background activities. Seven pre-defined interim outcome measures provided an indication of the effect of the intervention and were assessed using intention-to-treat analysis. These were supplemented by qualitative data from nine semi-structured interviews. The mean number of public communications supporting healthy food made by intervention companies was 1.5 versus 1.8 for control companies (p = 0.63). Other outcomes, including the mean number of news articles, comments and reports (1.2 vs. 1.4; p = 0.72), a published nutrition policy (23% vs. 44%; p = 0.21), public commitment to the Australian government’s Food and Health Dialogue (FHD) (41% vs. 61%; p = 0.24), evidence of a salt reduction plan (23% vs. 30%; p = 0.56), and mean number of communications with the NGO (15 vs. 11; p = 0.28) were also not significantly different. Qualitative data indicated the advocacy trial had little effect. The absence of detectable effects of the advocacy intervention on the interim markers indicates there may be no impact of the NGO advocacy trial on the primary outcome of salt reduction in processed foods

    An Approach to Nonparametric Inference on the Causal Dose Response Function

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    The causal dose response curve is commonly selected as the statistical parameter of interest in studies where the goal is to understand the effect of a continuous exposure on an outcome.Most of the available methodology for statistical inference on the dose-response function in the continuous exposure setting requires strong parametric assumptions on the probability distribution. Such parametric assumptions are typically untenable in practice and lead to invalid inference. It is often preferable to instead use nonparametric methods for inference, which only make mild assumptions about the data-generating mechanism. We propose a nonparametric test of the null hypothesis that the dose-response function is equal to a constant function. We argue that when the null hypothesis holds, the dose-response function has zero variance. Thus, one can test the null hypothesis by assessing whether there is sufficient evidence to claim that the variance is positive. We construct a novel estimator for the variance of the dose-response function, for which we can fully characterize the null limiting distribution and thus perform well-calibrated tests of the null hypothesis. We also present an approach for constructing simultaneous confidence bands for the dose-response function by inverting our proposed hypothesis test. We assess the validity of our proposal in a simulation study. In a data example, we study, in a population of patients who have initiated treatment for HIV, how the distance required to travel to an HIV clinic affects retention in care.Comment: 39 pages, 5 figure

    Inflammatory responses to induced infectious endometritis in mares resistant or susceptible to persistent endometritis

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    BACKGROUND: The objective of the study was to evaluate the gene expression of inflammatory cytokines (interleukin [IL]-1β, IL-6, IL-8, IL-10, tumor necrosis factor [TNF]-α, IL-1 receptor antagonist [ra] and serum amyloid A (SAA) in endometrial tissue and circulating leukocytes in response to uterine inoculation of 105 colony forming units (CFU) Escherichia coli in mares. Before inoculation, mares were classified as resistant or susceptible to persistent endometritis based on their uterine inflammatory response to infusion of 109 killed spermatozoa and histological assessment of the endometrial quality. Endometrial biopsies were obtained 3, 12, 24 and 72 hours (h) after bacterial inoculation and blood samples were obtained during the 7 day period post bacterial inoculation. Expression levels of cytokines and SAA were determined by quantitative real-time reverse transcriptase PCR (qRT-PCR). RESULTS: Compared to levels in a control biopsy (obtained in the subsequent estrous), resistant mares showed an up-regulation of IL-1β, IL-6, IL-8 and TNF-α at 3 h after E. coli inoculation, while susceptible mares showed increased gene expression of IL-6 and IL-1ra. Susceptible mares had a significant lower gene expression of TNF-α,IL-6 and increased expression of IL-1ra 3 h after E. coli inoculation compared to resistant mares. Susceptible mares showed a sustained and prolonged inflammatory response with increased gene expression levels of IL-1β, IL-8, IL-1ra and IL-1β:IL-1ra ratio throughout the entire study period (72 h), whereas levels in resistant mares returned to estrous control levels by 12 hours. Endometrial mRNA transcripts of IL-1β and IL-1ra were significantly higher in mares with heavy uterine bacterial growth compared to mares with no/mild growth.All blood parameters were unaffected by intrauterine E. coli infusion, except for a lower gene expression of IL-10 at 168 h and an increased expression of IL-1ra at 48 h observed in susceptible mares compared to resistant mares. CONCLUSIONS: The current investigation suggests that endometrial mRNA transcripts of pro-inflammatory cytokines in response to endometritis are finely regulated in resistant mares, with initial high expression levels followed by normalization within a short period of time. Susceptible mares had a prolonged expression of pro-inflammatory cytokines, supporting the hypothesis that an unbalanced endometrial gene expression of inflammatory cytokines might play an important role in the pathogenesis of persistent endometritis