998 resultados para 1995_03200110 TM-21 4500802


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The ground surface net solar radiation is the energy that drives physical and chemical processes at the ground surface. In this paper, multi-spectral data from the Landsat-5 TM, topographic data from a gridded digital elevation model, field measurements, and the atmosphere model LOWTRAN 7 are used to estimate surface net solar radiation over the FIFE site. Firstly an improved method is presented and used for calculating total surface incoming radiation. Then, surface albedo is integrated from surface reflectance factors derived from remotely sensed data from Landsat-5 TM. Finally, surface net solar radiation is calculated by subtracting surface upwelling radiation from the total surface incoming radiation.

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Sodium alumino-phosphate glasses co-doped with Yb(3+) and Tm(3+) ions have been prepared with notably low OH(-) content, and characterized from the viewpoint of their spectroscopic properties. In these glasses, Yb(3+) acts as an efficient sensitizer of excitation energy at 0.98 mu m - which can be provided by high power and low cost diode lasers, and subsequently undergoes non-resonant energy transfer to Tm(3+) ions ((2)F(5/2), (3)H(6) --> (2)F(7/2), (3)H(5)). Through this process, the emitting level (3)F(4) is rapidly populated, generating improved emission at 1.8 mu m ((3)F(4) --> (3)H(6)). In order to guarantee the efficiency of such favorable energy transfer, energy losses via multiphonon decay, Yb-Yb radiative trapping, and non- radiative transfer to OH(-) groups were evaluated, and minimized when possible. The dipole - dipole energy transfer microscopic parameters corresponding to Yb(3+) --> Tm(3+), Yb(3+) --> Yb(3+) and Tm(3+) --> Tm(3+) transfers, calculated by the Forster-Dexter model, are C(Yb-Tm) = 2.9 x 10(-40) cm(6) s(-1), C(Yb-Yb) = 42 x 10(-40) cm(6) s(-1) and C(Tm-Tm) = 43 x 10(-40) cm(6) s(-1), respectively.

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One of the agreements assumed at the conference of the United Nations for the Environments and Development which took place in Rio de Janeiro in 1992; through Global Agenda 21, was that the signatory countries would create a national Politics of sustainable development, by means of their national Agenda 21. Demonstrating the relevance of municipal districts and the local communities, during the definitions of new development standards compromised to the transformation of the society, socia1ly and environmentally well-balanced world, it was also agreed on that places under the responsibilities of the municipal districts would promote their own local Agenda 21. We need to point out though that the government has the prerogative and the responsibly of facilitating the population participation process in the construction of national and local Agenda. This made it possible again, to plan the scheming process directly towards the insertion of population participation at the different levels, involving the entire local sectors while establishing a new local partnership through the local municipal government. Thus, we decide to verify the participation of the population in the construction of their local Agenda 21, choosing for the study case Parnamirim municipality from RN. The question which originated the objectives and analysis was formulated on the following terms: Up to which stage was the process of population participation effective in the elaboration of Parnamirims's local Agenda 21? Based on this uneasiness, it was defined as the general objective, the verification of population participation process during the elaboration of Parnamirims's local Agenda 21, aiming at its effectiveness as well as specific objectives; to identify the population representivity, the construction of the local AG 21 in order to identify on which level is the participation based, to verify the strategies used in order to promote the process participation, to identify the motives guiding those involved in the construction of the local Agenda 21. This case study at Parnamirim municipal district demonstrated that there was effective population participation as far as the local Agenda 21 is concerned

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This work reports on the preparation, structural and luminescent studies of nanosized up-converter phosphors Y2O2S:Yb(4%), Er(0.1%) and Y2O2S:Yb(4%), Tm(0.1%),both from polymeric and basic carbonate precursors. The precursors were submitted to a sulphuration process that was previously developed for oxysulfide preparation from basic carbonate. From XRD data, all phosphors presented the oxysulfide phase and the mean crystallite size estimated from the Scherrer formula in the range of 15-20 nm. Polymeric precursor leads to the smallest crystallite size independent on the doping ion. SEM and TEM results confirmed that basic carbonate leads to spherical particles with narrow size distribution and mean diameter of 150 nm, and polymeric precursor smaller spherical particles with diameter between 20 and 40 nm. Up-conversion studies under 980 nm laser excitation showed that Er-doped phosphors present strong green emission related to H-2(11/2), S-4(3/2) --> I-4(15/2) Er transitions as well as the red ones, F-4(9/2) --> I-4(15/2). Tm-doped samples show strong blue emission assigned to (1)G(4) --> H-3(6) and also the red ones, related to (1)G(4) --> F-3(4). Therefore, the sulphuration method was successfully applied to prepare nanosized and nanostructured blue and green up-converter oxysulfide phosphors starting from basic carbonate and polymeric precursors. (C) 2003 Elsevier B.V. All rights reserved.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The aim of this study was to investigate the effects of beta-alanine supplementation on exercise capacity and the muscle carnosine content in elderly subjects. Eighteen healthy elderly subjects (60-80 years, 10 female and 4 male) were randomly assigned to receive either beta-alanine (BA, n = 12) or placebo (PL, n = 6) for 12 weeks. The BA group received 3.2 g of beta-alanine per day (2 x 800 mg sustained-release Carnosyn (TM) tablets, given 2 times per day). The PL group received 2 x (2 x 800 mg) of a matched placebo. At baseline (PRE) and after 12 weeks (POST-12) of supplementation, assessments were made of the muscle carnosine content, anaerobic exercise capacity, muscle function, quality of life, physical activity and food intake. A significant increase in the muscle carnosine content of the gastrocnemius muscle was shown in the BA group (+85.4%) when compared with the PL group (+7.2%) (p = 0.004; ES: 1.21). The time-to-exhaustion in the constant-load submaximal test (i.e., TLIM) was significantly improved (p = 0.05; ES: 1.71) in the BA group (+36.5%) versus the PL group (+8.6%). Similarly, time-to-exhaustion in the incremental test was also significantly increased (p = 0.04; ES 1.03) following beta-alanine supplementation (+12.2%) when compared with placebo (+0.1%). Significant positive correlations were also shown between the relative change in the muscle carnosine content and the relative change in the time-to-exhaustion in the TLIM test (r = 0.62; p = 0.01) and in the incremental test (r = 0.48; p = 0.02). In summary, the current data indicate for the first time, that beta-alanine supplementation is effective in increasing the muscle carnosine content in healthy elderly subjects, with subsequent improvement in their exercise capacity.

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The cooperation and the sharing of information cataloguing and bibliographical in environment automated, this was only possible with the creation and adoption of interchange format MARC21. But due to the progresses of the technologies of information and communication, of the crescent use of Internet and of the databases and databanks, there were the need of the creation and development of tools that optimize the organization activities, retrieval and interchange of information. XML is one of those developments that have as purpose to facilitate the management, storage and transmission of data through Internet. Before that, it was proposed through a literature revision, to analyze Interchange Format MARC21 and Markup Language XML as tools for the consolidation of the Automated Cooperative Cataloguing, your differences of storage flexibilities, organization, retrieval and interchange of data through Internet. This research made possible the divulgation to the community librarian, through a literature revision, that has been discussed internationally on MARC21 and XML