2,482 research outputs found

    Occupational Choice and Compensation for Losers from International Trade

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    What lies behind serum urate concentration? Insights from genetic and genomic studies

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    Many factors, including genetic components and acquired factors such as obesity and alcohol consumption, influence serum uric acid (urate) concentrations. Since serum urate concentrations are determined by the balance between renal urate excretion and the volume of urate produced via purine metabolism, urate transporter genes as well as genes coding for enzymes involved in purine metabolism affect serum urate concentrations. URAT1 was the first transporter affecting serum urate concentrations to be identified. Using the characterization of this transporter as an indicator, several transporters have been shown to transport urate, allowing the construction of a synoptic renal urate transport model. Notable re-absorptive urate transporters are URAT1 at apical membranes and GLUT9 at basolateral membranes, while ABCG2, MRP4 (multidrug resistance protein 4) and NPT1 are secretive transporters at apical membranes. Recent genome-wide association studies have led to validation of the in vitro model constructed from each functional analysis of urate transporters, and identification of novel candidate genes related to urate metabolism and transport proteins, such as glucokinase regulatory protein (GKRP), PDZK1 and MCT9. However, the function and physiologic roles of several candidates, as well as the influence of acquired factors such as obesity, foods, or alcoholic beverages, remain unclear

    On Riemannian manifolds of non-positive sectional curvature admitting a killing vector field

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    Nanomachining of Fused Quartz Using Atomic Force Microscope

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    Nanomachining experiments on fused quartz surface have been performed using an atomic force microscope combined with a two-axis capacitive force/displacement transducer. The minimum normal force fnP needed to form reproducibly a groove was about 4.7 μN. The minimum critical normal force fnR, tangential force ftR, and groove depth dgR when the material removal process began were found to be 33.7 μN, 18.7 μN, and 4.3 nm, respectively. Characteristic changes in the swelling ratio Rs and the ratio of force components at the critical normal force fnR can be used to identify the critical condition for changing from plastic deformation to material removal process region

    A Model of Multi-Dimensional Human Capital Investment: Specific vs. general investments under uncertainty

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    Specialization and the division of labor are the sources of high productivity in modern society. When worker skills are multi-dimensional, workers may face a choice between general versus specific human capital investment. Given that individual agents face uncertainty in the relative output price, what are the optimal strategies for heterogeneous individual agents in human capital investment? In the absence of insurance markets, general investment gives an option value for changes in the environment. We analyze a model in which workers are born heterogeneous and are endowed with two-dimensional skills in different sectors, to determine if incentives exist for workers to invest in skills in which they had originally excelled or struggled. We find that some workers choose to invest in their weaker skill, via specific human capital investment, provided that the scale of the risk is big and that the parameter of relative risk aversion is greater than one. We find that there exist agents whose optimal human capital investment decisions reverse their ex ante comparative advantages ex post.
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