Estimation of heterogeneous preferences, with an application to demand for internet services

This paper presents a structural econometric framework for discrete and continuous consumer choices in which unobserved intrapersonal and interpersonal preference heterogeneity is modeled explicitly. It outlines a simulation-assisted estimation methodology applicable in this framework. This methodology is illustrated in an application to analyze data from the U.C. Berkeley Internet Demand Experiment

Advection-Dominated Accretion with Infall and Outflows

We present self-similar solutions for advection-dominated accretion flows with radial viscous force in the presence of outflows from the accretion flow or infall. The axisymmetric flow is treated in variables integrated over polar sections and the effects of infall and outflows on the accretion flow are parametrised for possible configurations compatible with the self-similar solution. We investigate the resulting accretion flows for three different viscosity laws and derive upper limits on the viscosity parameter alpha. In addition, we find a natural connection to non-rotating and spherical accretion with turbulent viscosity, which is assumed to persist even without differential rotation. Positive Bernoulli numbers for advection-dominated accretion allow a fraction of the gas to be expelled in an outflow and the upper limit on the viscosity predicts that outflows are inevitable for equations of state close to an ideal gas.Comment: 17 pages, 9 figures, accepted for publication in the Astrophysical Journa

Radiative Transfer Modeling of Three-Dimensional Clumpy AGN Tori and its Application to NGC 1068

Recent observations of NGC 1068 and other AGN support the idea of a geometrically and optically thick dust torus surrounding the central supermassive black hole and accretion disk of AGN. In type 2 AGN, the torus is seen roughly edge-on, leading to obscuration of the central radiation source and a silicate absorption feature near 10 micron. While most of the current torus models distribute the dust smoothly, there is growing evidence that the dust must be arranged in clouds. We describe a new method for modeling near- and mid-infrared emission of 3-dimensional clumpy tori using Monte Carlo simulations. We calculate the radiation fields of individual clouds at various distances from the AGN and distribute these clouds within the torus region. The properties of the individual clouds and their distribution within the torus are determined from a theoretical approach of self-gravitating clouds close to the shear limit in a gravitational potential. We demonstrate that clumpiness in AGN tori can overcome the problem of over-pronounced silicate features. Finally, we present model calculations for the prototypical Seyfert 2 galaxy NGC 1068 and compare them to recent high-resolution measurements. Our model is able to reproduce both the SED and the interferometric observations of NGC 1068 in the near- and mid-infrared.Comment: 16 pages, 16 figures, 6 tables (figures reduced due to astro-ph limitations); accepted by A&

Characterization of solar cells for space applications. Volume 12: Electrical characteristics of Solarex BSF, 2-ohm-cm, 50-micron solar cells (1978 pilot line) as a function of intensity, temperature, and irradiation

Electrical characteristics of Solarex back-surface-field, 2-ohm-cm, 50-micron N/P silicon solar cells are presented in graphical and tabular format as a function of solar illumination intensity, temperature, and irradiation

Characterization of solar cells for space applications. Volume 8: Electrical characteristics of Spectrolab BSF, BSR, textured 290-micron solar cells (K7) as a function of intensity, temperature and irradiation

A set of parametric data is presented on the Spectrolab textured, back-surface-field, back-surface-reflector solar cell which is a commercially available product

Characterization of solar cells for space applications. Volume 13: Electrical characteristics of Hughes LPE gallium arsenide solar cells as a function of intensity and temperature

Electrical characteristics of Hughes Liquid phase epitaxy, P/N gallium aluminum arsenide solar cells are presented in graphical and tabular format as a function of solar illumination intensity and temperature

Characterization of solar cells for space applications. Volume 11: Electrical characteristics of 2 ohm-cm, 228 micron wraparound solar cells as a function of intensity, temperature, and irradiation

Parametric characterization data on Spectrolab 2 by 4 cm, 2 ohm/cm, 228 micron thick wraparound cell, a candidate for the Solar Electric Propulsion Mission, are presented. These data consist of the electrical characteristics of the solar cell under a wide range of temperature and illumination intensity combinations of the type encountered in space applications

Estimativa de parâmetros de crescimento, produção e dinâmica de um fragmento de Floresta com Araucária usando dados de parcelas permanentes.

Editores técnicos: Marcílio José Thomazini, Elenice Fritzsons, Patrícia Raquel Silva, Guilherme Schnell e Schuhli, Denise Jeton Cardoso, Luziane Franciscon. EVINCI. Resumos

Geotecnologias como apoio à remedição de parcelas permanentes em Floresta Ombrófila Mista.

Resumo