91 resultados para TOA


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In this study, we assess changes of aerosol optical depth (AOD) and direct radiative forcing (DRF) in response to the reduction of anthropogenic emissions in four major pollution regions in the Northern Hemisphere by using results from nine global models in the framework of the Hemispheric Transport of Air Pollution (HTAP). DRF at top of atmosphere (TOA) and surface is estimated based on AOD results from the HTAP models and AOD-normalized DRF (NDRF) from a chemical transport model. The multimodel results show that, on average, a 20% reduction of anthropogenic emissions in North America, Europe, East Asia, and South Asia lowers the global mean AOD (all-sky TOA DRF) by 9.2% (9.0%), 3.5% (3.0%), and 9.4% (10.0%) for sulfate, particulate organic matter (POM), and black carbon (BC), respectively. Global annual average TOA all-sky forcing efficiency relative to particle or gaseous precursor emissions from the four regions (expressed as multimodel mean ± one standard deviation) is  ±3.5 ±0.8,  ±4.0 ±1.7, and 29.5 ±18.1mWm ±2 per Tg for sulfate (relative to SO2), POM, and BC, respectively. The impacts of the regional emission reductions on AOD and DRF extend well beyond the source regions because of intercontinental transport (ICT). On an annual basis, ICT accounts for 11 ±5% to 31 ±9% of AOD and DRF in a receptor region at continental or subcontinental scale, with domestic emissions accounting for the remainder, depending on regions and species. For sulfate AOD, the largest ICT contribution of 31 ±9% occurs in South Asia, which is dominated by the emissions from Europe. For BC AOD, the largest ICT contribution of 28 ±18% occurs in North America, which is dominated by the emissions from East Asia. The large spreads among models highlight the need to improve aerosol processes in models, and evaluate and constrain models with observations.

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Using the GlobAEROSOL-AATSR dataset, estimates of the instantaneous, clear-sky, direct aerosol radiative effect and radiative forcing have been produced for the year 2006. Aerosol Robotic Network sun-photometer measurements have been used to characterise the random and systematic error in the GlobAEROSOL product for 22 regions covering the globe. Representative aerosol properties for each region were derived from the results of a wide range of literature sources and, along with the de-biased GlobAEROSOL AODs, were used to drive an offline version of the Met Office unified model radiation scheme. In addition to the mean AOD, best-estimate run of the radiation scheme, a range of additional calculations were done to propagate uncertainty estimates in the AOD, optical properties, surface albedo and errors due to the temporal and spatial averaging of the AOD fields. This analysis produced monthly, regional estimates of the clear-sky aerosol radiative effect and its uncertainty, which were combined to produce annual, global mean values of (−6.7±3.9)Wm−2 at the top of atmosphere (TOA) and (−12±6)Wm−2 at the surface. These results were then used to give estimates of regional, clear-sky aerosol direct radiative forcing, using modelled pre-industrial AOD fields for the year 1750 calculated for the AEROCOM PRE experiment. However, as it was not possible to quantify the uncertainty in the pre-industrial aerosol loading, these figures can only be taken as indicative and their uncertainties as lower bounds on the likely errors. Although the uncertainty on aerosol radiative effect presented here is considerably larger than most previous estimates, the explicit inclusion of the major sources of error in the calculations suggest that they are closer to the true constraint on this figure from similar methodologies, and point to the need for more, improved estimates of both global aerosol loading and aerosol optical properties.

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A new coupled cloud physics–radiation parameterization of the bulk optical properties of ice clouds is presented. The parameterization is consistent with assumptions in the cloud physics scheme regarding particle size distributions (PSDs) and mass–dimensional relationships. The parameterization is based on a weighted ice crystal habit mixture model, and its bulk optical properties are parameterized as simple functions of wavelength and ice water content (IWC). This approach directly couples IWC to the bulk optical properties, negating the need for diagnosed variables, such as the ice crystal effective dimension. The parameterization is implemented into the Met Office Unified Model Global Atmosphere 5.0 (GA5) configuration. The GA5 configuration is used to simulate the annual 20-yr shortwave (SW) and longwave (LW) fluxes at the top of the atmosphere (TOA), as well as the temperature structure of the atmosphere, under various microphysical assumptions. The coupled parameterization is directly compared against the current operational radiation parameterization, while maintaining the same cloud physics assumptions. In this experiment, the impacts of the two parameterizations on the SW and LW radiative effects at TOA are also investigated and compared against observations. The 20-yr simulations are compared against the latest observations of the atmospheric temperature and radiative fluxes at TOA. The comparisons demonstrate that the choice of PSD and the assumed ice crystal shape distribution are as important as each other. Moreover, the consistent radiation parameterization removes a long-standing tropical troposphere cold temperature bias but slightly warms the southern midlatitudes by about 0.5 K.

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Satellite based top-of-atmosphere (TOA) and surface radiation budget observations are combined with mass corrected vertically integrated atmospheric energy divergence and tendency from reanalysis to infer the regional distribution of the TOA, atmospheric and surface energy budget terms over the globe. Hemispheric contrasts in the energy budget terms are used to determine the radiative and combined sensible and latent heat contributions to the cross-equatorial heat transports in the atmosphere (AHT_EQ) and ocean (OHT_EQ). The contrast in net atmospheric radiation implies an AHT_EQ from the northern hemisphere (NH) to the southern hemisphere (SH) (0.75 PW), while the hemispheric difference in sensible and latent heat implies an AHT_EQ in the opposite direction (0.51 PW), resulting in a net NH to SH AHT_EQ (0.24 PW). At the surface, the hemispheric contrast in the radiative component (0.95 PW) dominates, implying a 0.44 PW SH to NH OHT_EQ. Coupled model intercomparison project phase 5 (CMIP5) models with excessive net downward surface radiation and surface-to-atmosphere sensible and latent heat transport in the SH relative to the NH exhibit anomalous northward AHT_EQ and overestimate SH tropical precipitation. The hemispheric bias in net surface radiative flux is due to too much longwave surface radiative cooling in the NH tropics in both clear and all-sky conditions and excessive shortwave surface radiation in the SH subtropics and extratropics due to an underestimation in reflection by clouds.

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A single habit parameterization for the shortwave optical properties of cirrus is presented. The parameterization utilizes a hollow particle geometry, with stepped internal cavities as identified in laboratory and field studies. This particular habit was chosen as both experimental and theoretical results show that the particle exhibits lower asymmetry parameters when compared to solid crystals of the same aspect ratio. The aspect ratio of the particle was varied as a function of maximum dimension, D, in order to adhere to the same physical relationships assumed in the microphysical scheme in a configuration of the Met Office atmosphere-only global model, concerning particle mass, size and effective density. Single scattering properties were then computed using T-Matrix, Ray Tracing with Diffraction on Facets (RTDF) and Ray Tracing (RT) for small, medium, and large size parameters respectively. The scattering properties were integrated over 28 particle size distributions as used in the microphysical scheme. The fits were then parameterized as simple functions of Ice Water Content (IWC) for 6 shortwave bands. The parameterization was implemented into the GA6 configuration of the Met Office Unified Model along with the current operational long-wave parameterization. The GA6 configuration is used to simulate the annual twenty-year short-wave (SW) fluxes at top-of-atmosphere (TOA) and also the temperature and humidity structure of the atmosphere. The parameterization presented here is compared against the current operational model and a more recent habit mixture model.

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The gas retail represents the end of a section of the oil and natural gas derivative chain, for it is at this stage where the commercialization of those merchandises takes place towards the costumers. This process involves an enormous amount of economic agents, which reflects on an activity of great influence on the citizen's everyday. By the time of the gas retail price liberalization, in 2002, there were great expectations towards that measure, for the insertion of that segment in a competitive market was likely to create a decrease in prices. As there was not a drastic drop off in cost, the question was no longer the price itself, but, predominantly, the conduct taken by the economic agents that operate the market. Not in vain, the segment introduces a greater number of different procedures combined with the organs that compose the Brazilian System of Competition Protection. What is understood, however, is that many of these complaints are made in a lightly way, without a proper analysis of the market and its practices, that being why, in this paper, evidences the causes of these complaints and explained what, in fact, occurs in this market. Also, the organs that protect the free initiative in the sector use different methods to assess anticompetitive practices, which are counterproductive on the combat of anticompetitive practice, that being why the present paper analyzes the used methods on a critic perspective, choosing one which is believed to be the most adequate. The present work also tries to present the gas retail prices on a constitutional, free competition, free initiative and consumers defense perspective, analyzing the competition s aspects on the gas market; the shaping of the gas prices; the market boundaries; the anti-competitive practices under the gas market; and analyze the possibility, according to the defined economic standards in the constitutional text of existing a greater control or gas price indexing and/or regulation which limits the distributors and resellers profit on gas. Still, in consequence of this analysis, a study on Natal s market behavior will be developed in its competitive feature. That being said, moreover being a theoretical-descriptive study, data and statistics gathered is used, which will lead, willing to grasp an experiential study on a few aspects of the Potiguar gas retail market

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BMPs are components superfamily ligands transformation growth fator-β (TGF-β) secreted into the extracellular environment, with mechanisms of intercellular communication through specific ligands and receptors in various target cells, being recognized for its influence in osteogenic induction, also play an important role in tissue homeostasis, cell proliferation, differentiation control , in addition to being present in the development of various malignancies. The aim of this study was to compare the immunohistochemical expression of BMP-2, BMP-4 and its receptors BMPRIA and BMPRII in cases of ameloblastoma and adenomatoid odontogenic tumor. The sample consisted of 20 cases of solid ameloblastoma (SA), 10 cases of ameloblastoma unicystic (UA) and 16 cases of adenomatoid odontogenic tumor (AOT). The expression of BMPs and their receptors was evaluated in the parenchyma and stroma of lesions, establishing the percentage of immunopositive cells (0 - negative; 1-1 % to 10 % of cells positive; 2 - 11% to 25% of positive cells; 3 - 26% to 50% of cells positive; 4 - 51% to 75 % of positive cells; 5 - more than 75% positive cells). Analysis of the expression of BMP-2 revealed no statistically significant differences in parenchymal (p = 0.925) and stromal component (p = 0.345) between the groups, as well as BMP-4 (p = 0.873 / p = 0.131). In the epithelial component, SA and AOT had a higher frequency of score 5. In turn, all cases of UA were classified as score 5. The analysis of the stromal component showed no statistically significant difference between groups with respect to median scores BMPRIA positivity (p = 0.768) and BMPRII (p = 0.779). In the epithelial component of SA and UA, no statistically significant correlations between imunoexpression proteins analyzed were observed. In turn, the group of AOT, statistically significant positive correlations between the scores of expression of all studied proteins were found. In the stromal component, statistically significant positive correlations were found only in the SA group in BMP -4 and BMPRII (r = 0.476; p = .034), in the UA in BMP-4 and BMPRIA (r = 0.709; p = 0.022). The results of this study suggest that the BMPs and their receptors are involved in the development process odontogenic tumors. BMP-4, in turn, besides being present in odontogenic tumors have the capacity to form mineralized material.

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Let 0toA parallel to f parallel to + B parallel to f parallel to/ A theta(k) + B mu(k)hold. In each case we determine the corresponding extremal polynomials for which equalities are attained.

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Pós-graduação em Relações Internacionais (UNESP - UNICAMP - PUC-SP) - FFC

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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A análise do comportamento da precipitação em uma bacia hidrográfica é fundamental para a engenharia e gerenciamento dos recursos hídricos. A Região Hidrográfica Tocantins-Araguaia (RHTA) pela sua ocupação recente e potencialidades econômicas, ganha destaque no cenário nacional. Este trabalho avalia quantitativamente a dinâmica espaço-temporal da precipitação anual nesta região durante um período de 30 anos de dados. A dinâmica da precipitação pode ser analisada pelo cálculo da precipitação média em uma dada área, compondo assim mapas de isoietas de precipitação anual. No entanto, a confecção destes mapas requer um método de interpolação que melhor represente as características pluviométricas em locais não amostrados para posterior análise quantitativa do comportamento da precipitação. Para tanto, foram realizados análises exploratórias descritivas amostral e espacial como requisito de estacionaridade do método de interpolação geoestatístico, ajuste e validação do modelo teórico que se adéque ao variograma de precipitação anual. Após a confecção do mapa de isoietas pelo método de Krigagem Ordinária (sem tendência) e Krigagem Universal (com tendência) foi realizado o cálculo do volume precipitado na região hidrográfica pelo método dos contornos. A dinâmica espacial da precipitação foi realizada com base na análise da estatística descritiva, mapa de isoietas, mapa hipsométrico, Índice de Irregularidade Meteorológica (IMM) e Coeficiente de Variação. A dinâmica temporal foi analisada pela distribuição dos totais anuais de precipitação volumétrica para cada sub-bacia da RHTA, pelo Índice de Anomalia Padronizada, na variação interanual de precipitação e teste de tendência e magnitude representados respectivamente pelo Teste de Mann Kendall e Sen’s. Os resultados correlacionados com as anomalias meteorológicas do Oceano Atlântico (Dipolo) e Pacífico (ENOS) indicam o comportamento da precipitação bastante heterogêneo e com grande variabilidade temporal principalmente na sub-bacia Tocantins-Alto (TOA) (14%). Diminuição da amplitude pluviométrica, em anos de anomalia meteorológica intensa ocasionando um incremento de precipitação ao sul das sub-bacias TOA e ARA e diminuição da precipitação na sub-bacia TOB, em eventos de El Niño. Não se pode comprovar pelo teste de Mann Kendall que há uma tendência estatisticamente significativa no volume precipitado na RHTA, mas o estimador Sen’s dá indícios de queda na precipitação na sub-bacia TOA (-1,24 Km³/ano) e Araguaia (ARA) (-1,13 Km³/ano) e aumento da precipitação na sub-bacia do Tocantins Baixo (TOB) (0,53 Km³/ano) e para a RHTA (-1,5 Km³/ano). Assim a variabilidade espacial e temporal nas sub-bacias está intimamente relacionada aos eventos de anomalia meteorológica, na qual, a sua ação ocorre de maneira irregular ao longo da área de estudo e pode influenciar as diversas atividades sócio-econômicas na RHTA de acordo com sua magnitude e área de ocorrência.

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Investiga-se em que medida Hilda Hilst, em Fluxo-floema, vale-se de um conjunto de procedimentos que colocam em cena tanto o sujeito-narrador quanto o próprio narrar, de maneira destoante do que predominantemente se fazia à época. Se no contexto ditatorial era tendência relacionar a literatura a uma “função compensatória”, o que a autora oferece em sua estreia na prosa mostra-se de modo ambivalente, já que não abdica desse prisma, porém o relaciona à frustração. No caso do texto “Osmo”, isso se dá à medida em que se instaura um descompasso entre o “narrar prometido” e o “narrar empreendido”, o que acaba por evidenciar tanto o texto como construção verbal encenada quanto a ambígua atitude do narrador-personagem diante da necessidade de verbalizar a sua história e de se aproximar de seus receptores. O postergamento da história prometida gera a frustração, que é alegoricamente abarcada como um procedimento de tessitura do texto hilstiano relacionado à ironia, à violência, ao fracasso, e que ilumina a condição paradoxal do narrar e da relação do/da artista com o mercado literário.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)