1000 resultados para Guidage des tubes polliniques
Resumo:
This study aims to evaluate the feasibility of using simple techniques - pollen abortion rates, passive diffusive tubes (NO(2)) and trace element accumulation in tree barks - when determining the area of influence of pollution emissions produced in a traffic corridor. Measurements were performed at 0, 60 and 120 meters from a major road with high vehicular traffic, taking advantage of a sharp gradient that exists between the road and a cemetery. NO(2) values and trace elements measured at 0 meters were significantly higher than those measured at more distant points. Al, S. Cl, V. Fe, Cu, and Zn exhibited a higher concentration in tree barks at the vicinity of the traffic corridor. The same pattern was observed for the pollen abortion rates measured at the three different sites. Our data suggests that simple techniques may be applied either to validate dispersion land-based models in an urban settings or, alternatively, to provide better spatial resolution to air pollution exposure when high-resolution pollution monitoring data are not available. (C) 2011 Elsevier B.V. All rights reserved.
Resumo:
This paper describes U2DE, a finite-volume code that numerically solves the Euler equations. The code was used to perform multi-dimensional simulations of the gradual opening of a primary diaphragm in a shock tube. From the simulations, the speed of the developing shock wave was recorded and compared with other estimates. The ability of U2DE to compute shock speed was confirmed by comparing numerical results with the analytic solution for an ideal shock tube. For high initial pressure ratios across the diaphragm, previous experiments have shown that the measured shock speed can exceed the shock speed predicted by one-dimensional models. The shock speeds computed with the present multi-dimensional simulation were higher than those estimated by previous one-dimensional models and, thus, were closer to the experimental measurements. This indicates that multi-dimensional flow effects were partly responsible for the relatively high shock speeds measured in the experiments.
Resumo:
The distributed-tubes model of hepatic elimination is extended to include intermixing between sinusoids, resulting in the formulation of a new, interconnected-tubes model. The new model is analysed for the simple case of two interconnected tubes, where an exact solution is obtained. For the case of many strongly-interconnected tubes, it is shown that a zeroth-order approximation leads to the convection-dispersion model. As a consequence the dispersion number is expressed, for the first time, in terms of its main physiological determinants: heterogeneity of flow and density of interconnections between sinusoids. The analysis of multiple indicator dilution data from a perfused liver preparation using the simplest version of the model yields the estimate 10.3 for the average number of interconnections. The problem of boundary conditions for the dispersion model is considered from the viewpoint that the dispersion-convection equation is a zeroth-order approximation to the equations for the interconnected-tubes model. (C) 1997 Academic Press Limited.
Resumo:
In the kallikrein-kinin and renin-angiotensin systems the main receptors, B-1 and B-2 (kinin receptors) and AT(1) and AT(2) (angiotensin receptors) respectively, are seven-transmembrane domain G-protein-coupled receptors. Considering that the B, agonists Des-Arg(9)-BK (Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe), Lys-desArg(9)-BK or Des-Arg(10)-KD (Lys-Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe) and the AT, agonist (Asp-Arg-Val-Tyr-lle-His-Pro-Phe) have the same two residues at the C-terminal region (i.e. Pro-Phe), we hypothesized that TM V and TM VI of the B-1 receptor could play an essential role in agonist binding and activity, being these regions receptor sites for binding the C-terminal sequences of Des-Arg-kinins similarly to that observed to AT, receptor. To investigate this hypothesis, we replaced Arg(212) for Ala at the top of the TM V and the sequence 274-282 (CPYHFFAFL) in TM VI of the rat kinin B, receptor by the 32 receptor homologous sequence, 289-297 (FPFQISTFL) and subsequently analyzed the consequences of these mutations by competition binding and functional assays. Despite correct expression, observed at the mRNA and protein level by RT-PCR and confocal microscopy, respectively, no agonist binding and function was verified for the mutated receptors. Therefore, our results suggest an important role for Arg(212) in the TM V and a region of TM VI of rat B, receptor in the interaction with the C-terminal residues of Des-Arg-kinins, similar to that observed with AngII. (c) 2007 Elsevier B.V. All rights reserved.
Resumo:
Expansion tubes operating at total flow enthalpies of 100 MJ kg(-1) or more have characteristical test times of 30-50 mus. Under these conditions, the response time of the Pitot pressure measuring device is critical when performing flow calibration studies. The conventional technique of using a commercial pressure transducer protected by shielding has not always proven to be effective, due to the relatively large (and variable) response time caused by the shielding. A device called the stress wave bar gauge has been designed and calibrated and shown to be an effective way to measure the Pitot pressure with a response time of only 2-3 mus.
Resumo:
Stepped cascades and spillways have been used for more than 3,500 years. The recent regain of interest for the stepped chute design is associated with the introduction of new construction techniques, the development of new design techniques and newer applications. Stepped chute flows are characterised by significant free-surface aeration that cannot be neglected. Two-phase flow measurements were conducted in a large-size model (h =0.10 m, α = 22o). Experimental observations demonstrate the existence of a transition flow regime for a relatively wide range of flow rates. Detailed air-water flow measurements were conducted for both skimming flows and transition flows. Skimming flows exhibit gradual variations of the air-water flow properties, whereas transition flows are characterised by rapid flow redistributions between adjacent steps.
Resumo:
O estudo de caso descreve o processo de planejamento estrat??gico ocorrido em uma organiza????o p??blica e os resultados alcan??ados ap??s a sua implanta????o. A organiza????o, com o nome fict??cio de Companhia de Defesa, desenvolveu seu planejamento estrat??gico com inten????o de aderir ?? administra????o estrat??gica. Os principais problemas reconhecidos pela organiza????o s??o a morosidade, a falta de transpar??ncia e a inefici??ncia de suas a????es. Atuaram no planejamento estrat??gico a alta administra????o, coordenadores nomeados e representantes regionais e uma consultoria especializada. O ambiente organizacional existente ?? ??poca n??o foi prop??cio ao planejamento estrat??gico: mudan??as de dire????o, pouca capacita????o funcional, capilaridade da institui????o e dificuldade de consenso entre planejadores e executores. ?? poss??vel, ??queles que estudarem o caso, contrapor a teoria e a pr??tica do planejamento estrat??gico, identificando boas a????es realizadas e erros cometidos
Resumo:
Plus d???une vingtaine d???ann??es d???existence d??di??es ?? la mission de d??velopper les comp??tences des fonctionnaires pour augmenter la capacit?? de l?????tat dans la gestion des politiques publiques fait de l???ENAP un mod??le dans le domaine de la formation. Rattach??e au Minist??re du Plan, du Budget et de la Gestion, l?????cole, d??s sa cr??ation en 1986, a re??ue 245 mille fonctionnaires de tout le pays. En 2007, 26 mille fonctionnaires de l???administration f??d??rale ont attendu un de nos 60 stages offerts.