Caracterização de sistemas de manejo de bacurizeiro (Platonia insignis mart.) nas mesorregiões do Nordeste paraense e do Marajó, estado do Pará.

O bacurizeiro (Platonia insignis Mart.) é uma espécie arbórea de porte médio a grande com aproveitamento frutífero, madeireiro e energético, com centro de origem na Amazônia Oriental. Assume importância econômica nos estados do Pará, Maranhão e Piauí, onde se concentram densas e diversificadas populações naturais, em áreas de vegetação secundária. O objetivo deste estudo foi identificar e observar as práticas realizadas nos sistemas (extrativo, manejado e plantado) desenvolvidos pelos agricultores familiares das mesorregiões do Nordeste Paraense e Marajó, tendo em vista o seu potencial de crescimento como produto para agroindústria e para a recuperação de áreas degradadas na Amazônia Oriental. A amostra foi constituída por 108 agricultores familiares das duas mesorregiões, todos georeferenciados com os quais foram abordados aspectos relativos à disponibilidade de bacurizeiros em seus estabelecimentos, o tipo de manejo e as práticas adotadas. Espera-se, com a adoção de manejo adequado desses sistemas, a transformação de roçados abandonados em pomares de bacurizeiros com espaçamento definido, os quais poderiam ser viabilizados mediante a utilização de linhas de crédito específicas

Molecular Dynamics Simulations

A tutorial introduction to the technique of Molecular Dynamics (MD) is given, and some characteristic examples of applications are described. The purpose and scope of these simulations and the relation to other simulation methods is discussed, and the basic MD algorithms are described. The sampling of intensive variables (temperature T, pressure p) in runs carried out in the microcanonical (NVE) ensemble (N= particle number, V = volume, E = energy) is discussed, as well as the realization of other ensembles (e.g. the NVT ensemble). For a typical application example, molten SiO2, the estimation of various transport coefficients (self-diffusion constants, viscosity, thermal conductivity) is discussed. As an example of Non-Equilibrium Molecular Dynamics (NEMD), a study of a glass-forming polymer melt under shear is mentioned.Comment: 38 pages, 11 figures, to appear in J. Phys.: Condens. Matte

Elastic Constants of Quantum Solids by Path Integral Simulations

Two methods are proposed to evaluate the second-order elastic constants of quantum mechanically treated solids. One method is based on path-integral simulations in the (NVT) ensemble using an estimator for elastic constants. The other method is based on simulations in the (NpT) ensemble exploiting the relationship between strain fluctuations and elastic constants. The strengths and weaknesses of the methods are discussed thoroughly. We show how one can reduce statistical and systematic errors associated with so-called primitive estimators. The methods are then applied to solid argon at atmospheric pressures and solid helium 3 (hcp, fcc, and bcc) under varying pressures. Good agreement with available experimental data on elastic constants is found for helium 3. Predictions are made for the thermal expectation value of the kinetic energy of solid helium 3.Comment: 9 pages doublecolumn, 6 figures, submitted to PR

Does type of hospital ownership influence physicians' daily work schedules? An observational real-time study in German hospital departments

Background: During the last two decades the German hospital sector has been engaged in a constant process of transformation. One obvious sign of this is the growing amount of hospital privatization. To date, most research studies have focused on the effects of privatization regarding financial outcomes and quality of care, leaving important organizational issues unexplored. Yet little attention has been devoted to the effects of privatization on physicians' working routines. The aim of this observational real-time study is to deliver exact data about physicians' work at hospitals of different ownership. By analysing working hours, further impacts of hospital privatization can be assessed and areas of improvement identified. Methods: Observations were made by shadowing 100 physicians working in private, for-profit or non-profit as well as public hospital departments individually during whole weekday shifts in urban German settings. A total of 300 days of observations were conducted. All working activities were recorded, accurate to the second, by using a mobile personal computer. Results: Results have shown significant differences in physicians' working activities, depending on hospital ownership, concerning working hours and time spent on direct and indirect patient care. Conclusion: This is the first real-time analysis on differences in work activities depending on hospital ownership. The study provides an objective insight into physicians' daily work routines at hospitals of different ownership, with additional information on effects of hospital privatization