2,620 research outputs found

    A Model of Incentive Compatibility under Moral Hazard in Livestock Disease Outbreak Response

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    This paper uses a principal-agent model to examine incentive compatibility in the presence of information asymmetry between the government and individual producers. Prior models of livestock disease have not incorporated information asymmetry between livestock managers and social planners. By incorporating the asymmetry, we investigate the role of incentives in producer behavior that influences the duration and magnitude of a disease epidemic.livestock disease, moral hazard, principal-agent model, Institutional and Behavioral Economics,

    Livestock Disease Indemnity Design When Moral Hazard is Followed by Adverse Selection

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    Averting or limiting the outbreak of infectious disease in domestic livestock herds is an economic and potential human health issue that involves both the government and individual livestock producers. Producers have private information about preventive biosecurity measures they adopt on their farms prior to outbreak (ex ante moral hazard), and following outbreak they possess private information about whether or not their herd is infected (ex post adverse selection). We investigate how indemnity payments can be designed to provide incentives to producers to invest in biosecurity and report infection to the government, while simultaneously addressing the information asymmetry between producers and the government. We show how addressing the adverse selection problem leads to a risk-sharing tradeoff in the moral hazard problem. We compare the relative magnitude of the first- and second-best levels of biosecurity investment and indemnity payments to further demonstrate the tradeoff between risk-sharing and efficiency, and we discuss the implications for status quo U.S. policy.Food Consumption/Nutrition/Food Safety, Livestock Production/Industries, Risk and Uncertainty,

    Quantumness in decoherent quantum walk using measurement-induced disturbance

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    The classicalization of a decoherent discrete-time quantum walk on a line or an n-cycle can be demonstrated in various ways that do not necessarily provide a geometry-independent description. For example, the position probability distribution becomes increasingly Gaussian, with a concomitant fall in the standard deviation, in the former case, but not in the latter. As another example, each step of the quantum walk on a line may be subjected to an arbitrary phase gate, without affecting the position probability distribution, no matter whether the walk is noiseless or noisy. This symmetry, which is absent in the case of noiseless cyclic walk, but is restored in the presence of sufficient noise, serves as an indicator of classicalization, but only in the cyclic case. Here we show that the degree of quantum correlations between the coin and position degrees of freedom, quantified by a measure based on the disturbance induced by local measurements (Luo, Phys. Rev. A 77, 022301 (2008)), provides a suitable measure of classicalization across both type of walks. Applying this measure to compare the two walks, we find that cyclic quantum walks tend to classicalize faster than quantum walks on a line because of more efficient phase randomization due to the self-interference of the two counter-rotating waves. We model noise as acting on the coin, and given by the squeezed generalized amplitude damping (SGAD) channel, which generalizes the generalized amplitude damping channel.Comment: 8 pages with 8 figures, Published versio

    Asymptotic Dynamics in Quantum Field Theory

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    A crucial element of scattering theory and the LSZ reduction formula is the assumption that the coupling vanishes at large times. This is known not to hold for the theories of the Standard Model and in general such asymptotic dynamics is not well understood. We give a description of asymptotic dynamics in field theories which incorporates the important features of weak convergence and physical boundary conditions. Applications to theories with three and four point interactions are presented and the results are shown to be completely consistent with the results of perturbation theory.Comment: 18 pages, 3 figure

    Full-duplex optical communication system

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    A method of full-duplex electromagnetic communication wherein a pair of data modulation formats are selected for the forward and return data links respectively such that the forward data electro-magnetic beam serves as a carrier for the return data. A method of encoding optical information is used wherein right-hand and left-hand circular polarizations are assigned to optical information to represent binary states. An application for an earth to low earth orbit optical communications system is presented which implements the full-duplex communication and circular polarization keying modulation format

    Relationship between vascularity, age and survival in non-small-cell lung cancer.

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    Lung tumours in the elderly show reduced growth potential; impaired angiogenesis may contribute to this phenomenon. Recent studies have suggested that the angiogenic potential of a tumour may be inferred by the vascularity measured in histological sections. The purpose of this study has been to determine whether vascularity is related to age, survival or other clinical parameters in resected non-small-cell lung cancer (NSCLC). A group of 88 consecutive patients with a follow-up period of at least 5 years was selected. The group exhibited a wide age range (37-78 years) and similar survival characteristics to those of the general NSCLC population. Tumour sections were stained with a pan-endothelial antibody (vWF) and vascularity was quantitated, without knowledge of the clinical details, by three methods: highest microvascular density; average microvascular density; and average microvascular volume. The results were analysed by non-parametric statistical tests. A correlation was found between all three methods of quantitation. Vascularity was not associated with age, sex, tumour type, stage, volume, size (TNM-T) nodal status (TNM-N) or survival. However, survival time was generally longer for patients with higher vascularity, reaching borderline significance (P = 0.06) for the average microvascular density values. Higher tumour volume (P = 0.02) and stage (P = 0.05) were associated with lower survival times. Using multivariate survival analysis, tumour volume was the only factor related to survival. We conclude that vascularity is not associated with age and has no significant prognostic value in NSCLC

    INTEGRAL observations of the blazar Mrk 421 in outburst (Results of a multi-wavelength campaign)

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    We report the results of a multi-wavelength campaign on the blazar Mrk 421 during outburst. We observed four strong flares at X-ray energies that were not seen at other wavelengths (partially because of missing data). From the fastest rise in the X-rays, an upper limit could be derived on the extension of the emission region. A time lag between high-energy and low-energy X-rays was observed, which allowed an estimation of the magnetic-field strength. The spectral analysis of the X-rays revealed a slight spectral hardening of the low-energy (3 - 43 keV) spectral index. The hardness-ratio analysis of the Swift-XRT (0.2 - 10 keV) data indicated a small correlation with the intensity; i. e., a hard-to-soft evolution was observed. At the energies of IBIS/ISGRI (20 - 150 keV), such correlations are less obvious. A multiwavelength spectrum was composed and the X-ray and bolometric luminosities are calculated.Comment: 15 pages, 18 figures; accepted by Astronomy & Astrophysic

    Coulomb gauge Gribov copies and the confining potential

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    We study the approach, initiated by Marinari et al., to the static inter-quark potential based on Polyakov lines of finite temporal extent, evaluated in Coulomb gauge. We show that, at small spatial separations, the potential can be understood as being between two separately gauge invariant colour charges. At larger separations Gribov copies obstruct the non-perturbative identification of individually gauge invariant colour states. We demonstrate, for the first time, how gauge invariance can be maintained quite generally by averaging over Gribov copies. This allows us to extend the analysis of the Polyakov lines and the corresponding, gauge invariant quark-antiquark state to all distance scales. Using large scale lattice simulations, we show that this interpolating state possesses a good overlap with the ground state in the quark-antiquark sector and yields the full static inter-quark potential at all distances. A visual representation of the Gribov copies on the lattice is also presented.Comment: 22 pages, 9 figures, v2: minor changes, references adde

    ‘Codeine is my companion’: misuse and dependence on codeine containing medicines in Ireland

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    Objectives: Global concern around over the counter availability of codeine containing products and risk of misuse, dependence and related harms are evident. A phenomenological study of lived experiences of codeine misuse and dependence was undertaken in Ireland, following the Pharmaceutical Society of Ireland’s 2010 guidelines for restricted supply of non-prescription codeine containing products. Methods: In-depth interviews were conducted with a purposive sample of adult codeine misusers and dependents (n=21), both actively using, in treatment and in recovery. The narratives were analysed using the Empirical Phenomenological Psychological five-step method (Karlsson, 1995). A total of 10 themes with 82 categories were identified. Two concepts at a higher level of abstraction above the theme-level emerged during the final stage of analysis. The concepts identified were ‘emotional pain and user self-legitimization of use’ and ‘entrapment into habit-forming and invisible dependent use’. These concepts were reported in different ways by a majority of participants. Results: Findings are presented under the following themes: (1) profile and product preferences; (2) awareness of habit forming use and harm; (3) negotiating pharmacy sales; (4) alternative sourcing routes; (5) the codeine feeling; (6) the daily routine; (7) acute and chronic side effects; (8) social isolation; (9) withdrawal and dependence and (10) help-seeking and treatment experiences. Conclusions: There is a public health and regulatory imperative to develop proactive responses tackling public availability of codeine containing medicines, risk minimisation in consumer self-treatment for pain, enhanced patient awareness of potential for habit forming use and its consequences and continued health professional pharmacovigilence. © College of Psychiatrists of Ireland 201
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