41,883 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,

    Dielectronic recombination data for astrophysical applications: Plasma rate-coefficients for Fe^q+ (q=7-10, 13-22) and Ni^25+ ions from storage-ring experiments

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    This review summarizes the present status of an ongoing experimental effort to provide reliable rate coefficients for dielectronic recombination of highly charged iron ions for the modeling of astrophysical and other plasmas. The experimental work has been carried out over more than a decade at the heavy-ion storage-ring TSR of the Max-Planck-Institute for Nuclear Physics in Heidelberg, Germany. The experimental and data reduction procedures are outlined. The role of previously disregarded processes such as fine-structure core excitations and trielectronic recombination is highlighted. Plasma rate coefficients for dielectronic recombination of Fe^q+ ions (q=7-10, 13-22) and Ni^25+ are presented graphically and in a simple parameterized form allowing for easy use in plasma modeling codes. It is concluded that storage-ring experiments are presently the only source for reliable low-temperature dielectronic recombination rate-coefficients of complex ions.Comment: submitted for publication in the International Review of Atomic and Molecular Physics, 8 figures, 3 tables, 68 reference

    Using non-speech sounds to provide navigation cues

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    This article describes 3 experiments that investigate the possibiity of using structured nonspeech audio messages called earcons to provide navigational cues in a menu hierarchy. A hierarchy of 27 nodes and 4 levels was created with an earcon for each node. Rules were defined for the creation of hierarchical earcons at each node. Participants had to identify their location in the hierarchy by listening to an earcon. Results of the first experiment showed that participants could identify their location with 81.5% accuracy, indicating that earcons were a powerful method of communicating hierarchy information. One proposed use for such navigation cues is in telephone-based interfaces (TBIs) where navigation is a problem. The first experiment did not address the particular problems of earcons in TBIs such as “does the lower quality of sound over the telephone lower recall rates,” “can users remember earcons over a period of time.” and “what effect does training type have on recall?” An experiment was conducted and results showed that sound quality did lower the recall of earcons. However; redesign of the earcons overcame this problem with 73% recalled correctly. Participants could still recall earcons at this level after a week had passed. Training type also affected recall. With personal training participants recalled 73% of the earcons, but with purely textual training results were significantly lower. These results show that earcons can provide good navigation cues for TBIs. The final experiment used compound, rather than hierarchical earcons to represent the hierarchy from the first experiment. Results showed that with sounds constructed in this way participants could recall 97% of the earcons. These experiments have developed our general understanding of earcons. A hierarchy three times larger than any previously created was tested, and this was also the first test of the recall of earcons over time

    Storage-ring measurement of the hyperfine induced 47Ti18+(2s 2p 3P0 -> 2s2 1S0) transition rate

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    The hyperfine induced 2s 2p 3P0 > 2s2 1S0 transition rate AHFI in berylliumlike 47Ti18+ was measured. Resonant electron-ion recombination in a heavy-ion storage ring was employed to monitor the time dependent population of the 3P0 state. The experimental value AHFI=0.56(3)/s is almost 60% larger than theoretically predicted.Comment: 4 pages. 3 figures, 1 table, accepted for publication in Physical Review Letter

    Anomalous Lattice Response at the Mott Transition in a Quasi-2D Organic Conductor

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    Discontinuous changes of the lattice parameters at the Mott metal-insulator transition are detected by high-resolution dilatometry on deuterated crystals of the layered organic conductor κ\kappa-(BEDT-TTF)2_{2}Cu[N(CN)2_{2}]Br. The uniaxial expansivities uncover a striking and unexpected anisotropy, notably a zero-effect along the in-plane c-axis along which the electronic interactions are relatively strong. A huge thermal expansion anomaly is observed near the end-point of the first-order transition line enabling to explore the critical behavior with very high sensitivity. The analysis yields critical fluctuations with an exponent α~\tilde{\alpha} \simeq 0.8 ±\pm 0.15 at odds with the novel criticality recently proposed for these materials [Kagawa \textit{et al.}, Nature \textbf{436}, 534 (2005)]. Our data suggest an intricate role of the lattice degrees of freedom in the Mott transition for the present materials.Comment: 4 pages, 4 figure
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