65,425 research outputs found

    Estimating the Demand for Health Care with Panel Data: A Semiparametric Bayesian Approach

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    This paper is concerned with the problem of estimating the demand for health care with panel data. A random effects model is specifed in a semiparametric Bayesian fashion using a Dirichlet process prior. This results in a very exible mixture distribution with an in nite number of components for the random effects. Therefore, the model can be seen as a natural extension of prevailing latent class models. A full Bayesian analysis using Markov chain Monte Carlo (MCMC)simulation methods is discussed. The methodology is illustrated with an application using data from Germany

    An analysis of atmospheric entry trajectories for manned and unmanned missions to the planet Venus

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    A unified atmospheric density model is presented for the planet Venus, and this model is compatible with Russian and American data obtained during the 1967 Venus launch opportunity. Trajectory characteristics involved in atmospheric entry are discussed with reference to roll-control modulation and entry corridor. Subsequent to a trajectory-oriented discussion of potential Venus mission characteristics, a parametric analysis of manned and unmanned vehicle entry trajectories into the Venusian atmosphere is presented. A sensitivity analysis with reference to atmospheric density deviations is included to show the dependence of corridor depth on the atmospheric density profile

    Lagoon water-level oscillations driven by rainfall and wave climate

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    Barrier breaching and subsequent inlet formation represent critical processes that ensure the temporary or permanent connection and transference of water, nutrients, or living organisms between a lagoon and the open sea. Here, we investigate the conditions inducing natural barrier breaching through a 34 months monitoring program of water-level oscillations within a shallow lagoon and the adjacent nearshore, at the Northern coast of the Iberian Peninsula, Louro lagoon. Seven natural openings were identified to have occurred during the three monitored wet seasons, from the 2009 to 2012, (Wet1, Wet2 and Wet3); four in the Wetl, two in the Wet2 and one in. the Wet3. The openings were grouped in three types depending on the observed relation between the lagoon water-level (L-wl), the estimated berm height (B-h) and the water-level at the beach (B-wl): (i) openings by lagoon outflow, which include those characterized by L-wl higher than B-h and lower B-wl; (ii) openings by wave inundation, including those induced by B-wl higher than B-h, and (iii) mixed openings, which result from a combination of the two previous conditions. We observed that L-wl is modulated by the rainfall regime (R-f) and can be explained by the accumulated precipitation. We estimated applying runup equations to obtain B-h and B-wl which depend on the wave climate and tidal level. The inlet lifespan was found to be regulated by the wave climate and rainfall regime; in particular barrier sealing was associated with a sudden increase in wave period and a reduction in precipitation. This work proves that the natural openings could be predicted successfully with support to medium term water-level monitoring programs, which in turn may significantly contribute to strategic decision making for management and conservation purposes.Xunta de Galicia [08MDS036000PR, PlanI2C-ED481B 2014/132-0]MICINN [CTM2012-39599-C03-01]Portuguese Science Foundation [IF/01047/2014]info:eu-repo/semantics/publishedVersio

    Transverse parton momenta in single inclusive hadron production in e+e−{e^ + }{e^ - } annihilation processes

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    We study the transverse momentum distributions of single inclusive hadron production in e+e−{e^ + }{e^ - } annihilation processes. Although the only available experimental data are scarce and quite old, we find that the fundamental features of transverse momentum dependent (TMD) evolution, historically addressed in Drell-Yan processes and, more recently, in Semi-inclusive deep inelastic scattering processes, are visible in e+e−{e^ + }{e^ - } annihilations as well. Interesting effects related to its non-perturbative regime can be observed. We test two different parameterizations for the p⊥p_\perp dependence of the cross section: the usual Gaussian distribution and a power-law model. We find the latter to be more appropriate in describing this particular set of experimental data, over a relatively large range of p⊥p_\perp values. We use this model to map some of the features of the data within the framework of TMD evolution, and discuss the caveats of this and other possible interpretations, related to the one-dimensional nature of the available experimental data
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