3,427 research outputs found

    Agri-environment Policy Design With Hidden Information and Hidden Action: Input Quotas vs Input Charges

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    Moxey, White and Ozanne (1999) have shown how transfer payments coupled with input quotas can be used to design optimal truth-telling mechanisms for voluntary agri-environmental schemes under hidden information about compliance costs. Ozanne, Hogan and Colman (2001) adapted the Moxey et al. model to analyze hidden action in such schemes, analyzing the relationships between input abatement, the cost of monitoring compliance and farmers’ risk preferences. White (2002) extended the Moxey et al. model to analyze the design of contracts under both hidden action and hidden information, but used an input charge/transfer payment approach rather than the original input quota/transfer payment one. In addition, he assumed that farmers caught cheating face a variable fine, related to the amount of input they apply in excess of the amount agreed in the contract, rather than a fixed fine as assumed by Ozanne et al. White argues that his results show that an input charge/transfer payment policy is more efficient than a quota when the regulator cannot observe compliance costs of individual farmers. This paper integrates the previous work, developing a model of both hidden action and hidden information in agri-environmental schemes based on the input quota/transfer payment approach of Moxey et al. (1999) and Ozanne et al. (2001), rather than the input charge/transfer payment approach of White (2002), but the variable fine of the latter rather than the fixed fine assumed by Ozanne et al. This integrated model shows that, contrary to White (2002), the input quota and input charges approaches lead to identical outcomes in terms of abatement levels, compensation payments, monitoring costs, probabilities and social welfare.Environmental Economics and Policy,

    Hidden action, risk aversion and variable fines in agri-environmental schemes

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    This note analyses the design of agri-environmental schemes for risk-averse producers whose input usage is only observable by costly monitoring. The scheme penalises producers in proportion to input use in excess of a quota. A striking result is that if the scheme is designed in such a way that producers always comply with the quota, risk aversion is not relevant in determining the level of input use.agri-environmental policy, monitoring, risk aversion, Environmental Economics and Policy, Risk and Uncertainty,

    To Work or Not to Work … That is the Question: Labour Market Decisions in the Classroom

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    This paper presents a simple classroom experiment for first-year university students of introductory economics, about participation in a competitive labour market. The students are designated as workers and the lecturer/tutor represents the numerous employers in this experiment. The experiment is run for several periods, each period representing different conditions in the labour market. During each period, workers must decide whether or not to offer their labour services based on the information they have at hand. We find that this participatory approach to teaching basic labour market concepts is not only well-received by students, but that it is just as effective at promoting students' retention and understanding.

    SDF-1 and PDGF enhance [alpha]v[beta]5-mediated ERK activation and adhesion-independent growth of human pre-B cell lines

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    CD23 acts through the [alpha]v[beta]5 integrin to promote growth of human pre-B cell lines in an adhesion-independent manner. [alpha]v[beta]5 is expressed on normal B-cell precursors in the bone marrow. Soluble CD23 (sCD23), short CD23-derived peptides containing the arg-lys-cys (RKC) motif recognized by [alpha]v[beta]5 and anti-[alpha]v[beta]5 monoclonal antibodies (MAbs) all sustain growth of pre-B cell lines. The chemokine stromal cell-derived factor-1 (SDF-1) regulates key processes during B-cell development. SDF-1 enhanced the growth-sustaining effect driven by ligation of [alpha]v[beta]5 with anti-[alpha]v[beta]5 MAb 15F-11, sCD23 or CD23-derived RKC-containing peptides. This effect was restricted to B-cell precursors and was specific to SDF-1. The enhancement in growth was associated with the activation of extracellular signal-regulated kinase (ERK) and both these responses were attenuated by the MEK inhibitor U0126. Finally, platelet-derived growth factor also enhanced both [alpha]v[beta]5-mediated cell growth and ERK activation. The data suggest that adhesion-independent growth-promoting signals delivered to B-cell precursors through the [alpha]v[beta]5 integrin can be modulated by cross-talk with receptors linked to both G-protein and tyrosine kinase-coupled signalling pathways

    Performance of a Boussinesq model for shoaling and breaking waves : a comparison with large scale laboratory data

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    In this thesis, a nonlinear model predicting hydrodynamics data for waves shoaling and breaking on a beach is reproduced and extensively tested with laboratory data. The model is based on the 1D Boussinesq equations as derived by Madsen et al. (1991) and Madsen and Sorensen (1992), with the free surface elevation and the depth-integrated velocity as variables. It allows slowly varying bathymetries and contains additional high order terms to improve the frequency dispersion for shorter wave periods, and thus also to improve the shoaling properties of the model. Wave breaking is modelled using the concept of a surface roller as formulated by Schäffer et al. (1993). It is assumed that bottom friction is negligible. A large scale laboratory experiment (Supertank), designed in particular to obtain data to test the validity of wave propagation models, provides the wave and current data. Wave evolution over a complex bathymetry is examined for 4 cases. The data include conditions for long and short waves, and regular and irregular waves. During the model evaluation, emphasis is put on the study of parameters of importance to sediment transport, including (orbital) velocity, undertow and wave shape prediction. The latter encompasses velocity and elevation skewness, kurtosis and asymmetry. It is found that, despite an overestimation of the depth-averaged horizontal velocity in some cases, the predicted velocity moments and undertow are in good agreement with the data. Using a bispectral analysis, it is shown that the nonlinear transfers of energy amongst the low order harmonics are well reproduced, but that errors are introduced in the treatment of the high order super-harmonics. As a result, the short waves tests are found to yield better results than those for long waves. A sensitivity analysis on the free parameters introduced in the simulation of wave breaking is carried out. It appears that the results are mostly sensitive to the critical xv avve fi-ont slope OB , and in particular that the elevation and velocity skewness and kurtosis predictions are very sensitive to this parameter.the University of Plymouth

    Can mHealth Improve Risk Assessment in Underserved Populations? Acceptability of a Breast Health Questionnaire App in Ethnically Diverse, Older, Low-Income Women.

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    Background: Use of mobile health (mHealth) tools has expanded rapidly but little research has been done on its acceptability by low-income, diverse, older patient populations. Objective: To assess the attitudes of a diverse group of underserved women on the acceptability and usability of mHealth tools in a clinical setting using a breast health questionnaire application (app) at a public hospital mammography clinic. Methods: Semi-structured interviews were conducted in a breast-imaging center of an urban safety net institution from July-August 2012. Interviews included pre- and post-questions. Women completed the Athena breast health questionnaire app on an iPad and were asked about their experience and ways to improve the tool. Results: Fifteen women age 45-75 years from diverse ethnic and educational backgrounds were interviewed. The majority of women, 11 of 15, preferred the Athena app over a paper version and all the women thought the app was easy to use. Two Spanish-speaking Latinas preferred paper; and two women, with limited mobile phone use, did not have a preference. Many women indicated that it would be necessary to have staff available for instruction and assistance if the app were to be implemented. Conclusions: mHealth tools are an acceptable, if not preferred, method of collecting health information for diverse, older, low-income women. Further studies are required to evaluate the reliability and accuracy of data collection using mHealth tools in underserved populations. mHealth tools should be explored as a novel way to engage diverse populations to improve clinical care and bridge gaps in health disparities
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