998 resultados para Upper semi-continuity


Relevância:

30.00% 30.00%

Publicador:

Resumo:

The operational details of the apparent electrical conductivity (ECa) sensor manufactured by Veris Technologies have been extensively documented in literature reports, but the geographical distribution of these research studies indicate a strong regional concentration in the US Mid-west and Southern states. The agricultural lands of these states diverge significantly to the soil conditions and water regime of irrigated land in the US South-western states such as Arizona where there is no previous research reports of the use of this particular sensor. The objectives of the present study were to analyze the performance of this sensor under the conditions of typical soils in irrigated farms of Central Arizona. We tested under static conditions the performance of the sensor on three soils of contrasting texture. Observations were collected as time series data as soil moisture changed from saturation to permanent wilting point. Observations were repeated at the hours of lowest and highest temperatures. In addition, this study included soil penetration resistance and salinity determinations. Preliminary results indicate that soil temperature of the upper layer caused the most dynamic change in the sensor output. The ECa curves of the three soil textures tested had well defined distinctive characteristics. Final multivariate analysis is pending.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Objective: To describe the preoperative upper limb lymphoscintigraphic pattern in women with breast cancer. Methods: Thirty-seven patients undergoing lymphoscintigraphy within 30 days of surgery were investigated. Lymphoscintigraphic studies of 37 upper limbs ipsilateral to surgery and 32 contralateral upper limbs were performed. The examination protocol consisted in obtaining static images of the upper limb in semi-flexion after 10 minutes, and 1 and 2 hours after subcutaneous injection of 1 mCi (37 MBq) of Tc-99m-dextran in the dorsum of the hand. The velocity of axillary lymph node visualization (I, visible at 10 minutes; II, 1 hour; III, 2 hours; and IV, invisible) and degree (intensity) of nodal uptake (a, marked; b, moderate; c,mild; and d, absent) were analyzed. Results: Optimal lymphatic functional pattern (Ia) was observed in four (11%) patients, in the ipsilateral upper limb, and six (19%), in the contralateral upper limb. Worse condition was observed in three (8%) patients (IVd) in the ipsilateral upper limb and two (6%) patients in the contralateral upper limb. The remaining patients showed intermediate states of velocity and uptake intensity. Conclusion: This study found relevant changes in preoperative lymphoscintigraphy, demonstrating preexisting functional differences in the lymphatic system. © 2011 Elsevier Editora Ltda.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

To describe the preoperative upper limb lymphoscintigraphic pattern in women with breast cancer. Thirty-seven patients undergoing lymphoscintigraphy within 30 days of surgery were investigated. Lymphoscintigraphic studies of 37 upper limbs ipsilateral to surgery and 32 contralateral upper limbs were performed. The examination protocol consisted in obtaining static images of the upper limb in semi-flexion after 10 minutes, and 1 and 2 hours after subcutaneous injection of 1 mCi (37 MBq) of Tc-99m-dextran in the dorsum of the hand. The velocity of axillary lymph node visualization (I, visible at 10 minutes; II, 1 hour; III, 2 hours; and IV, invisible) and degree (intensity) of nodal uptake (a, marked; b, moderate; c,mild; and d, absent) were analyzed. Optimal lymphatic functional pattern (Ia) was observed in four (11%) patients, in the ipsilateral upper limb, and six (19%), in the contralateral upper limb. Worse condition was observed in three (8%) patients (IVd) in the ipsilateral upper limb and two (6%) patients in the contralateral upper limb. The remaining patients showed intermediate states of velocity and uptake intensity. This study found relevant changes in preoperative lymphoscintigraphy, demonstrating preexisting functional differences in the lymphatic system.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

O presente trabalho teve como objetivo principal analisar as mudanças nas formas de venda e consumo do açaí na Região Metropolitana de Belém (RMB), e sua relação com a identidade de lugar de seus consumidores. O interesse pelo tema teve origem na observação da ocorrência da globalização do açaí, alimento base da dieta das populações amazônicas de origem ribeirinha que hoje é largamente consumido fora da Região Amazônica, em padrões muito diferentes daqueles nela estabelecidos. A escolha da RMB como lócus de pesquisa se justifica pelo fato de que nela se concentra alto consumo de açaí, nos padrões tradicionais e nos modernos, suscitando questionamentos sobre os efeitos dessa convivência na vida cotidiana dos que a habitam. Teoricamente, a pesquisa articula a definição de identidade de lugar de Abe-Lima (2012) com as elaborações de Henri Lefèbvre (1991) sobre a vida cotidiana no mundo moderno e com teoria dos circuitos econômicos de Milton Santos (2008). Metodologicamente, foi adotada uma estratégia multimétodos, envolvendo pesquisa documental, um painel de especialistas com 5 entidades de acompanhamento da produção de açaí, observações pautadas na etnografia urbana em 9 locais de venda e entrevistas semiabertas com 40 consumidores de açaí, maiores de 18 anos e residentes na RMB, recrutados por meio de cadeia tipo bola de neve. Além dos roteiros de entrevistas, foram utilizados como estratégias de coleta de dados diários de campo e fotografias. O conjunto dos dados foi submetido à técnica da análise de conteúdo temática, com eventual apoio do software QDA Miner Lite. Os resultados situaram a globalização do açaí em meados da década de 1990, momento de intensificação dos efeitos da metropolização em Belém, como o aumento populacional, a segregação espacial e a imposição de um ritmo de vida mais acelerado. As análises apontaram que tal processo significou a entrada do açaí no circuito superior da economia, com um processo produtivo mais organizado, utilizando mais tecnologia e envolvendo maiores volumes financeiros, atingindo escala industrial. No entanto, prevalece na RMB o processamento artesanal, em estruturas de pequeno porte, construídas em alvenaria, de organização simples e controle financeiro ausente. O consumo público aumentou, com grande número de locais especializados na oferta de açaí, em caráter de entretenimento, sendo incipiente a adesão a novos acompanhamentos, como granola e aveia. A preferência pelos acompanhamentos tradicionais, como farinha d’água ou de tapioca, açúcar e peixe, permanece, assim como pelo consumo privado, no âmbito da casa, que tem sido favorecido pela disponibilidade do serviço de entrega, recurso recente. A frequência geral de consumo diminuiu, em função do aumento de preço e de mudanças na rotina, como aumento da distância entre local de trabalho e residência. A pesquisa permitiu reafirmar a importância do açaí na vida cotidiana dos belenenses que o consomem, para os quais ele funciona como elemento de distintividade, continuidade, autoestima e autoeficácia, em estreita relação com aspectos próprios da metrópole. Por esse motivo, torna-se preocupante que o acesso a açaí de qualidade, nos padrões desejados pelos indivíduos, esteja tornando-SE privilégio inacessível aos consumidores de menor poder aquisitivo. Assim, espera-se que o conjunto de dados contribua para a compreensão da importância de políticas públicas voltadas ao açaí que considerem melhor as demandas daqueles que o consomem.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevância:

30.00% 30.00%

Publicador:

Resumo:

In this paper we study the continuity of invariant sets for nonautonomous infinite-dimensional dynamical systems under singular perturbations. We extend the existing results on lower-semicontinuity of attractors of autonomous and nonautonomous dynamical systems. This is accomplished through a detailed analysis of the structure of the invariant sets and its behavior under perturbation. We prove that a bounded hyperbolic global solutions persists under singular perturbations and that their nonlinear unstable manifold behave continuously. To accomplish this, we need to establish results on roughness of exponential dichotomies under these singular perturbations. Our results imply that, if the limiting pullback attractor of a nonautonomous dynamical system is the closure of a countable union of unstable manifolds of global bounded hyperbolic solutions, then it behaves continuously (upper and lower) under singular perturbations.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Agroforestry parklands represent a vast majority of the agricultural landscape under subsistent-oriented farming in semi-arid West Africa. Parklands are characterized by the growth of well- maintained trees (e.g., shea) on cultivated fields as a result of both environmental and human influences. Shea (Vitellaria paradoxa) provides a cultural and economic benefit to the local people of Ghana, especially women. Periods between traditional fallow rotation systems have reduced recently due to agricultural development and a demand for higher production. As a result, shea trees, which regenerate during fallow periods, has decreased over the landscape. The aim of this study was to determine beneficial spatial distributions of V. paradoxa to maintain high yields of staple crops, and how management of V. paradoxa will differ between male and female farmers as a result of farmer based needs and use of shea. Vegetation growth and grain yield of maize (Zea mays) associated with individual trees, clumped trees, and open fields were measured. Soil moisture and light availability were also measured to determine how V. paradoxa affected resource availability of maize in either clumped or scattered distributions of V. paradoxa. As expected, light availability increased as measurement locations moved farther away from all trees. However, soil moisture was actually greater under trees in clumps than under individual trees. Maize stalk height and cob length showed no difference between clumped and single trees at each measurement location. Grain yield per plot and per cob increased as measurement locations moved farther from single trees, but was actually greater near clumped trees that in the open field subplots. Cob length and maize stalk height increased with greater light availability, but grain yield per cob or per plot showed no relationship with light, but were not affected by soil moisture. Conversely, grain yield increased with increasing soil moisture, but had no relationship with light availability. Initial farming capital is the largest constraint to female farmers; therefore the collection of shea can help provide women with added income that could meet their specific farming needs. Our data indicate that overall effects of maintaining clumped distributions of V. paradoxa provided beneficial microclimates for staple crops when compared to single trees. It is recommended that male and female farmers allow shea to grow in clumped spatial distributions rather than maintaining scattered, individual trees.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The first operations at the new High-altitude Maïdo Observatory at La Réunion began in 2013. The Maïdo Lidar Calibration Campaign (MALICCA) was organized there in April 2013 and has focused on the validation of the thermodynamic parameters (temperature, water vapor, and wind) measured with many instruments including the new very large lidar for water vapor and temperature profiles. The aim of this publication consists of providing an overview of the different instruments deployed during this campaign and their status, some of the targeted scientific questions and associated instrumental issues. Some specific detailed studies for some individual techniques were addressed elsewhere. This study shows that temperature profiles were obtained from the ground to the mesopause (80 km) thanks to the lidar and regular meteorological balloon-borne sondes with an overlap range showing good agreement. Water vapor is also monitored from the ground to the mesopause by using the Raman lidar and microwave techniques. Both techniques need to be pushed to their limit to reduce the missing range in the lower stratosphere. Total columns obtained from global positioning system or spectrometers are valuable for checking the calibration and ensuring vertical continuity. The lidar can also provide the vertical cloud structure that is a valuable complementary piece of information when investigating the water vapor cycle. Finally, wind vertical profiles, which were obtained from sondes, are now also retrieved at Maïdo from the newly implemented microwave technique and the lidar. Stable calibrations as well as a small-scale dynamical structure are required to monitor the thermodynamic state of the middle atmosphere, ensure validation of satellite sensors, study the transport of water vapor in the vicinity of the tropical tropopause and study their link with cirrus clouds and cyclones and the impact of small-scale dynamics (gravity waves) and their link with the mean state of the mesosphere.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Paleontological and petrological studies of clay beds in the Basilika Formation (Tertiary age) are the subject of this paper. The petrology of the beds indicates that their main constituents were derived from volcanic activity and represent bentonites. Differing composition of the beds may suggest several spatially separated eruptions. The volcanic source area probably lay towards the north of the present Tertiary outcrops of Svalbard. Two foraminiferal assemblages are found in the bentonites: the lower is dominated by arenaceous forms while the upper consists of calcareous species.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Our main goal is to compute or estimate the calmness modulus of the argmin mapping of linear semi-infinite optimization problems under canonical perturbations, i.e., perturbations of the objective function together with continuous perturbations of the right-hand side of the constraint system (with respect to an index ranging in a compact Hausdorff space). Specifically, we provide a lower bound on the calmness modulus for semi-infinite programs with unique optimal solution which turns out to be the exact modulus when the problem is finitely constrained. The relationship between the calmness of the argmin mapping and the same property for the (sub)level set mapping (with respect to the objective function), for semi-infinite programs and without requiring the uniqueness of the nominal solution, is explored, too, providing an upper bound on the calmness modulus of the argmin mapping. When confined to finitely constrained problems, we also provide a computable upper bound as it only relies on the nominal data and parameters, not involving elements in a neighborhood. Illustrative examples are provided.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Soil degradation threatens agricultural production and food security in Sub-Saharan Africa. In the coming decades, soil degradation, in particular soil erosion, will become worse through the expansion of agriculture into savannah and forest and changes in climate. This study aims to improve the understanding of how land use and climate change affect the hydrological cycle and soil erosion rates at the catchment scale. We used the semi-distributed, time-continuous erosion model SWAT (Soil Water Assessment Tool) to quantify runoff processes and sheet and rill erosion in the Upper Ouémé River catchment (14500 km**2, Central Benin) for the period 1998-2005. We could then evaluate a range of land use and climate change scenarios with the SWAT model for the period 2001-2050 using spatial data from the land use model CLUE-S and the regional climate model REMO. Field investigations were performed to parameterise a soil map, to measure suspended sediment concentrations for model calibration and validation and to characterise erosion forms, degraded agricultural fields and soil conservation practices. Modelling results reveal current "hotspots" of soil erosion in the north-western, eastern and north-eastern parts of the Upper Ouémé catchment. As a consequence of rapid expansion of agricultural areas triggered by high population growth (partially caused by migration) and resulting increases in surface runoff and topsoil erosion, the mean sediment yield in the Upper Ouémé River outlet is expected to increase by 42 to 95% by 2025, depending on the land use scenario. In contrast, changes in climate variables led to decreases in sediment yield of 5 to 14% in 2001-2025 and 17 to 24% in 2026-2050. Combined scenarios showed the dominance of land use change leading to changes in mean sediment yield of -2 to +31% in 2001-2025. Scenario results vary considerably within the catchment. Current "hotspots" of soil erosion will aggravate, and a new "hotspot" will appear in the southern part of the catchment. Although only small parts of the Upper Ouémé catchment belong to the most degraded zones in the country, sustainable soil and plant management practices should be promoted in the entire catchment. The results of this study can support planning of soil conservation activities in Benin.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Regions containing internal boundaries such as composite materials arise in many applications.We consider a situation of a layered domain in IR3 containing a nite number of bounded cavities. The model is stationary heat transfer given by the Laplace equation with piecewise constant conductivity. The heat ux (a Neumann condition) is imposed on the bottom of the layered region and various boundary conditions are imposed on the cavities. The usual transmission (interface) conditions are satised at the interface layer, that is continuity of the solution and its normal derivative. To eciently calculate the stationary temperature eld in the semi-innite region, we employ a Green's matrix technique and reduce the problem to boundary integral equations (weakly singular) over the bounded surfaces of the cavities. For the numerical solution of these integral equations, we use Wienert's approach [20]. Assuming that each cavity is homeomorphic with the unit sphere, a fully discrete projection method with super-algebraic convergence order is proposed. A proof of an error estimate for the approximation is given as well. Numerical examples are presented that further highlights the eciency and accuracy of the proposed method.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

∗ The final version of this paper was sent to the editor when the author was supported by an ARC Small Grant of Dr. E. Tarafdar.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Митрофан М. Чобан, Петър Ст. Кендеров, Уорън Б. Муурс - Полу-топологична група (съответно, топологична група) е група, снабдена с топология, относно която груповата оперция произведение е частично непрекъсната по всяка от променливите (съответно, непрекъсната по съвкупност от променливите и обратната операция е също непрекъсната). В настоящата работа ние даваме условия, от топологичен характер, една полу-топологична група да е всъщност топологична група. Например, ние показваме, че всяка сепарабелна псевдокомпактна полу-топологична група е топологична група. Показваме също, че всяка локално псевдокомпактна полу-топологична група, чиято групова операция е непрекъсната по съвкупност от променливите е топологична група.