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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
181

Ocupação do Parque Estadual Delta do Jacuí : conflitos de uso territorial

Chiappetti, Ademir Baptista January 2005 (has links)
Esta dissertação tem por objetivo a análise da ocupação territorial do Parque Estadual Delta do Jacuí – PEDJ – tendo como foco principal os conflitos de uso territorial com a legislação atual, baseada no Sistema Nacional de Unidades de Conservação - SNUC. Possui uma perspectiva de abordagem centrada nas características naturais da paisagem do Delta do Jacuí, com o objetivo de destacar as suas qualidades, as quais justificam a sua preservação, nas formas de ocupações territoriais ocorridas entre o tempo atual e o correspondente ao ano de criação do PEDJ e na pesquisa qualitativa das percepções dos três segmentos que ocupam esse espaço geográfico: os moradores do Parque, as associações comunitárias e os representantes da Prefeitura Municipal de Eldorado do Sul. O estudo da percepção tem como objetivo a compreensão do lugar para esses grupos. A linha metodológica escolhida para essa análise está baseada no estudo dos conceitos de Paisagem, Território, Lugar e Percepção.
182

Potencial delta de Dirac em um cenário de comprimento mínimo.

GUSSON, M. F. 08 July 2016 (has links)
Made available in DSpace on 2018-08-01T21:59:21Z (GMT). No. of bitstreams: 1 tese_10075_Dissertação Michael França Gusson.pdf: 344550 bytes, checksum: d7e7c3bf981fdbfb58991d5655c87141 (MD5) Previous issue date: 2016-07-08 / Teorias que propõem a unificação da Relatividade Geral e da Mecânica Quântica, por exemplo a Gravitação Quântica e a Teoria de Cordas, apontam para a existência de um valor mínimo de comprimento observável. A existência deste implica em uma generalização do Princípio da Incerteza de Heisenberg, de modo a não admitir mais uma incerteza nula na posição, modificando assim a álgebra da Mecânica Quântica. Esta modificação na álgebra sugere uma reavaliação dos resultados obtidos nas situações usuais do contexto quântico. Neste trabalho é abordado o problema do potencial delta δ, sob um contexto de comprimento mínimo, e discutido as consequências e resultados relacionadas a esta generalização.
183

Estabilidade de ground state para a equação de Schrödinger logarítmica com potenciais do tipo delta / Stability of the ground states for a logarithmic Schrödinger equation with delta-type potentials

Alex Javier Hernandez Ardila 16 May 2016 (has links)
Na primeira parte do trabalho estudamos a equação de Schrödinger logarítmica com um delta potencial; $V(x)=-\\gamma \\,\\delta(x)$, onde $\\delta$ é a distribuição de Dirac na origem e o parâmetro real $\\gamma$ descreve a intensidade do potencial. Estabelecemos a existência e unicidade das soluções do problema de Cauchy associado em um espaço de funções adequado. No caso do potencial atrativo ($\\gamma>0$), calculamos de forma explícita o seu único ground state e mostramos a sua estabilidade orbital.\\\\ A segunda parte trata detalhadamente da equação de Schrödinger logarítmica com um delta derivada potencial; $V(x)=-\\gamma\\, \\delta^{\\prime}(x)$. A boa colocação global para o problema de Cauchy é verificada em um espaço de funções adequado. No caso do potencial atrativo ($\\gamma>0$), o conjunto dos ground states é completamente determinado. Mais precisamente: se $0<\\gamma\\leq2$, então há um único ground state e é uma função ímpar; se $\\gamma>2$, então existem dois ground states não-simétricos. Em adição, provamos que cada ground state é orbitalmente estável através de uma abordagem variacional. Finalmente, usando a teoria de extensão de operadores simétricos, também mostramos um resultado de instabilidade para $\\gamma>2$. / The first part of this thesis deals with the logarithmic Schrödinger equation with a delta potential; $V(x)=-\\gamma \\,\\delta(x)$, where $\\delta$ is the Dirac distribution at the origin and the real parameter $\\gamma$ is interpreted as the strength of the potential. We establish the existence and uniqueness of the solutions of the associated Cauchy problem in a suitable functional framework. In the attractive potential case ($\\gamma>0$), we explicitly compute the unique ground state and we show their orbital stability .\\\\ The second part deals with the case of the logarithmic Schrödinger equation with a delta prime potential; $V(x)=-\\gamma\\, \\delta^{\\prime}(x)$. Global well-posedness is verified for the Cauchy problem in a suitable functional space. In the attractive potential case ($\\gamma>0$), the set of the ground state is completely determined. More precisely: if $0<\\gamma\\leq2$, then there is a single ground state and it is an odd function; if $\\gamma>2$, then there exist two non-symmetric ground states. Moreover, we show that every ground state is orbitally stable via a variational approach. Finally, by applying the theory of extensions of symetric operators, we also prove a result of instability for $\\gamma>2$.
184

[en] DELTA MODULATION: CHANNEL ERRORS AND A COMPARATIVE ANALYSIS OF A/D CONVERTERS TO TRANSMIT VOICE SIGNALS / [pt] MODULOS DELTA: ERROS NO CANAL E ANALISE COMPARATIVA DE ALGUNS CONVERSORES A/D NA TRANSMISSÃO DE SINAIS DE VOZ

SAMUEL LEAO BENCHIMOL NETO 21 October 2009 (has links)
[pt] Este trabalho tem por objetivo basicamente fazer uma análise do desempenho de alguns sistemas delta, em particular, um sistema delta simples, um sistema delta estatístico e um sistema delta misto, quando em presença de erros no canal de transmissão com probabilidades de erro relativamente altas e tendo como sinal de entrada, processos Gauss-Markov de 1ª ordem. São feitas ainda análises comparativas entre sistemas delta para sinais de voz. Tais comparações examinam os comportamentos dos três sistemas citados acima e mais um sistema de Jayant, no qual foram introduzidas algumas modificações. Estas modificações incluem a utilização de um preditor de 6ª ordem e uma estratégia de amortecimento sobre os multiplicadores P e Q de Jayant. / [en] The basic objective of this work is to analyze the performance of several delta systems in the presence of channel errors, ocurring with relatively high probabilities. In this way, three systems were examined: a simple delta, a statistic delta and a mixed delta system. The input sequence was modeled as a first order Gauss-Markov process. Comparisons involving delta systems with voice signal inputs were also performed. The three above mentioned systems and a Jayant system were considered. Several modifications were introduced in this last system, including higher order predictors and damping schemes applied to P and Q multipliers.
185

Spatial and temporal variation of inundation in the Okavango Delta, Botswana; with special reference to areas used for flood recession cultivation

Dikgola, Kobamelo January 2015 (has links)
Philosophiae Doctor - PhD / The Okavango Delta is recognized as one of the famous inland wetlands and its sustainable use is important for socio-economic development of Botswana. The Okavango delta comprises permanent swamps, seasonal swamps, and drylands on islands within the delta and the surrounding areas, sustained by Okavango river inflows from upstream and local rainfall. TheOkavango River splits into several distributary channels within the delta. Areas which are flooded annually vary in response to varying inflows into the delta. Peak inflows into the delta occur during the February to May period. Due to the low gradient over the delta, these inflows move slowly resulting in peak outflows from the delta occurring during the June to August period. The inundated area over the entire delta increases from May until it reaches maximum inAugust and starts to decrease from September, reaching minimum inundated area in the months of December and January. The incoming flood wave into the delta and maximum inundation is out of phase with the local rainfall season.Communities living within and around the delta derive their livelihoods from tourism, hunting, fishing, livestock rearing, and crop production. Crop production is carried out on drylands and within floodplains. Some of the households take advantage of the increase in soil moisture arising from this inundation along floodplains to cultivate their crops as the floods recede. This practice is locally referred to as molapo farming which highly depends on inundation of floodplains. The availability of floodplain inundation highly depends on the magnitude of inflows into the delta and the local rainfall which are highly variable resulting in uncertainty regarding successful crop production, availability of livestock grazing areas, and uncertainty in reliance on the wetlands resources such as fishing. The uncertainty experienced in timing of extreme events which cause flooding of resulting in water reaching areas or floodplains where it is not wanted, and also uncertainity in timing of low flows, therefore water not reaching some parts of the delta.Several hydrological studies have been carried out with the aim of improving the understanding of the spatial and temporal dynamics of flows throughout the delta including predicting areas that are likely to be inundated each year. The significant gap addressed by this research is to improve the understanding of the spatial and temporal influence of magnitude and timing of flows on floodplain inundation. Local rainfall on the delta is highly variable over time and space due to its convective nature. This research also addresses the rainfall temporal and spatial variations and its implications on floodplain inundation. The knowledge about spatial extent and duration of floodplain inundation should assist in predicting each year the viability of molapo farming. Three research site, Shorobe, Tubu and Xobe are selected as case studies to understand the dynamics of floodplain inundation induced either by inflows or local rainfall. Local rainfall during the December to March period enables the crops to reach maturity. The onset of the rainy season is very important in supporting sowing of crop seeds. Local rainfall on the delta varies considerably. Aerial rainfall interpolation shows a change in rainfall magnitudes over space in different rainfall months, i.e different parts of the delta receive different rainfall magnitudes in different months of the rainy season. The spatial variation is mainly associated with the migration of the ITCZ southwards first through East Africa during October andNovember and down over Southern Africa in December to February. The movement of the ITCZ brings rainfall concentration on the northern and eastern parts of the Okavango Delta during December to January and bringing rainfall concentration to the northwestern part of the delta around February. However, rainfall spatial correlation between stations can be poor even within the first 150 km therefore implying neighboring places do not experience floodplain inundation by rainfall at the same time. The poor spatial correlation of rainfall between neighboring stations reflects the erratic nature of rainfall in the Okavango Delta characterised by localized thunderstorms. Change detection shows change points in rainfall which can be associated with ENSO episodes. A change point is identified in 1976 and 1977 which can be associated with the El Nino episodes during those years and two change points identified in 1999 and 2004 which can be associated with the La Nina episodes, therefore rainfall induced floodplain inundation can also be associated with wet and dry ENSO episodes. Rainfall does not show any significant trends except for an increasing trend on 10th percentile of Shakawe rainfall. Rainfall also does not show any cyclic behavior. Rainfall over the Okavango Delta can be divided into three unique homogenious sub-regions; sub-region 1: the northern part following the GEV probability distribution and being the region with highest rainfall amounts; sub-region 2: the lower northern and the outlet parts of the Okavango Delta following the GPA distribution with moderate rainfall; and sub-region 3: the middle part of the delta extending to the western and the eastern fringes of the delta, following the P3 distribution and having the lowest rainfall.The main characteristic that defines the Okavango Delta flows at Mohembo is its cyclic behavior. Three significant cycles are identified, close to 10, 20 and 40 years. No significant trends are identified, only a decreasing trend in minimum flows. Change points are identified in 1979 and 1988 and these can be explained by the existing cyclicity since no major land use changes have taken place in the Okavango River Basin upstream before 1989. The existence of cyclicity in Okavango River flows at Mohembo also explains the periodic wetting and drying of different floodplains in the delta. A long period of low flows was experienced from 1983 until 2003 and floodplain inundation extent was greatly reduced, more especially during the 1993-2003. During the 1993-2003 period, flows could no longer reach Maun Bridge along Thamalakne River, therefore leaving molapo floodplains around Boteti River, Gomoti River and Thaoge River to dry out. The 10 and 40 year return floods are important as they indicate the probability of a flood magnitude which has potential to result in major inundation in the Okavango Delta. Therefore, flood magnitudes with recurrence interval 10 and 40 years have high probability of occurring and can cause major floodplain inundation as they can be above the 2009 flood of 969 m3/s, which was the return of major inundation of Okavango Delta floodplains after a long period of dryness. The Ngoqa-Maunachira distributary channel of the Okavango River receives 32% of flow volumes entering the Okavango Delta at Mohembo. 12 % of the Mohembo flow volumes reach the Jao-Boro distributary whilst 1% is received by the Thaoge distributary. Therefore more inundation is experienced along the Ngoqa-Maunachira system compared to the other two. Only about 2% of the Mohembo flow volumes leave the Okavango Delta through Boteti River. Long term shifting of flow direction amongst reaches along the Okavango Delta distributaries is evident more especially along the Ngoqa-Maunachira River system. This results in shifting of inundation. Sub-surface water respond significantly to local rainfall and inflows with high soil moisture conditions retained at 60 cm and 100 cm below the ground.
186

Measuring bovine γδ T cell function at the site of Mycobacterium bovis infection

Rusk, Rachel Aline January 1900 (has links)
Master of Science in Biomedical Sciences / Department of Diagnostic Medicine/Pathobiology / Jodi L. McGill / The causative agent of tuberculosis (TB) in cattle is Mycobacterium bovis (M. bovis). γδ T cells are a unique subset of nonconventional T cells that play major roles in both the innate and adaptive arms of the immune system. Bovine γδ T cells have the capacity for multiple immune functions during infection with M. bovis. However, the alternative functions of γδ T cells as well as the responses of γδ T cells in vivo at the site of infection remain unclear. To identify novel functions for γδ T cells in response to M. bovis infections, RNA sequencing and transcriptomics analysis was completed on peripheral blood γδ T cells isolated from virulent M. bovis-infected cattle. Differentially expressed genes were confirmed with real-time PCR. In an attempt to model in vivo cell-to-cell interactions at the site of infection, γδ T cells were also isolated from naïve and M. bovis-infected calves and co-cultured with autologous, BCG-infected, monocyte-derived macrophages. γδ T cell chemokine and cytokine expression was analyzed via ELISA and real-time PCR. The characteristic lesions of bovine tuberculosis are well-organized pulmonary granulomas. To determine the relevance of the RNA-sequencing and in vitro co-culture results to in vivo infection, tissue samples from granulomatous lesions in the lungs and mediastinal lymph nodes of virulent M. bovis-infected cattle were collected 3 months after infection. mRNA transcripts for γδ T cells expression of-- IFN-γ, IL-17, IL-10, IL-22, and CCL2 were microscopically evaluated within the granulomas using an in situ hybridization system, RNAScope (Advanced Cell Diagnostics Inc.). Co-culture experiments and transcriptomics analysis revealed increased expression of chemokines and various cytokines by γδ T cells responding to M. bovis infection. The novel in situ hybridization assay revealed that cytokine expression by γδ T cells varied within the lesions, with significant levels of CCL2 and IFN-γ, and low expression of IL-10, IL-22, and IL-17 in situ at this time-point after infection. Co-culture experiments also revealed that γδ T cells from virulent M. bovis-infected cattle have the capacity to directly impact the viability of M. bovis in vitro. Our results suggest that γδ T cells accumulate within the granulomas, and influence host immunity to M. bovis by secretion of cytokines and chemokines, and direct cytotoxicity, in response to infected macrophages.
187

Land utilization in the lowland area of Delta Municipality

Taylor, Gordon deRupe January 1950 (has links)
The lowland area of Delta Municipality in Southwestern British Columbia comprising some 50 square miles with a population of 4,000 is one of the main suppliers of food to the Vancouver market. Although 10,000 acres classified as peat are unsuited for agricultural purposes, the remaining area has a fertile soil. In addition the area has a mild climate suited to the development of a dairying economy. Settlement of Delta started in 1868 and proceeded rapidly for several years. It was the wealth of the Fraser River fisheries rather than the agricultural productivity of the land that brought early prosperity to Delta and to Ladner, the municipal centre, in particular. After the decline of the fishing industry following the Hell's Gate disaster in 1913, agriculture became the economic mainstay of the district. As a result of poor internal transportation and a lack of fresh water in the western half of the municipality early agricultural practises differed in East Delta and in West Delta. Dairying developed in the east whereas cattle ranching became prominent in the west. In both sections similar field crops were grown. The opening of a road network after 1875 and the installation of a municipal water system in 1910 resulted in dairying gradually becoming the principal industry of Delta. In recent years a diversified agriculture has become the outstanding characteristic of the land use pattern in Delta. The major uses of land are for pasture, hay and oats, with lesser amounts devoted to potatoes, peas, and a variety of other crops. Most of the farm revenue comes from the sale of fluid milk to the Greater Vancouver market. There is some industrial activity in the area. Prior to 1913 salmon canning was important but declined consequent upon the diminishing of the Eraser River salmon runs. Between 1942 and 1944 two peat processing plants commenced operations upon the peat bog. They have become the largest industrial c concerns in Delta. A vegetable canning factory, a grass dehydration plant, and a grist mill are the local industries based upon agriculture. Ladner is the municipal centre and owes its prosperity to the surrounding farming community. Originally Ladner grew in response to the fishing industry. Summer resorts have grown up at Beach Grove and Boundary Bay. Sunbury is a small fishing community along the river and Tswassen is an Indian reservation. Since 1941 an area of 1,100 acres has been used for military purposes. The conclusions arrived at in the thesis were that the area should remain as agricultural land. Danger from flooding and the limited amount of good agricultural land near the city of Vancouver are two factors which should operate against urbanization of the fertile lowlands of the Fraser Valley. In the event that urban development should come a plan to provide the necessary services and to prevent friction with the farming community has been recommended. / Arts, Faculty of / Geography, Department of / Graduate
188

Regional development in the Zhujiang Delta, China, 1980-90

Lin, George Chu-Sheng 05 1900 (has links)
Against the background of a rapidly collapsing socialist empire in Eastern Europe and the former Soviet Union, socialist China has since the late 1970s consciously endeavored to develop a "socialist market economy with Chinese characteristics." This thesis assesses the process of economic and spatial transformation in the Zhujiang (Pearl River) Delta, one of the fastest growing economic regions in China. The purposes are to identify the general pattern of economic and spatial changes, to determine the key forces responsible for such changes, and to explore the theoretical implications of these changes in the broader context of interpretation about the operating mechanism of regional development. The overall objective is to understand how a regional economy under socialism is transformed after the intrusion of global market forces. My analyses of regional data and indepth case studies reveal that the Zhujiang Delta has since 1979 moved away from the previous impasse of involutionary growth or growth without development and entered a new era of real transformative development in which dramatic growth has occurred not only in agricultural and industrial output but also in labour productivity, per capita income, and employment. The take-off of the delta's regional economy has owed little to the expansion of state-run modern manufacturing, but has been fueled primarily by numerous small-scale, labour-intensive, and rural-base industries. The spatial outcome of this rural industrialization has been a rapid urbanization of the countryside, especially of the area adjacent to and between major metropolitan centres. There has been no increasing concentration of population in large cities as the conventional wisdom of urban transition might have predicted. Regional development in the Zhujiang Delta during the 1980s was not an outcome of any active state involvement. It was instead a result of relaxed control by the socialist central state over the delta's regional economy. Local governments, along with the collective and private sectors, are found to be the chief agents responsible for the transformation of the peasant economy and the development of the transport infrastructure. The penetration of global market forces via Hong Kong into the Zhujiang Delta has significantly facilitated the process of economic, spatial, and social transformation. This study of the operating mechanism of regional development in the Zhujiang Delta presents a dialectical model of local-global interaction to combat the two prevailing schools of exogenism and endogenism. It also suggests that previous theories on Chinese regional development, which assumed a strong socialist central state monopolizing local economic affairs, might need fundamental modifications. For the Zhujiang Delta, the development of which is still in the early take-off stage, the establishment of a modern transport infrastructure has shown remarkable effects, leading to rather than following the growth of the delta's economy. Finally, the relocation of transnational capital and manufacturing production from Hong Kong to the Zhujiang Delta has not displayed a spatial tendency of high concentration in the primate city as the conventional theory of globalization would suggest. Non-economic factors such as historical, cultural, and social linkages between investors and their target regions are found to have played a major role which should not be overlooked in understanding the mechanism and spatial patterns of the internationalization of production. / Arts, Faculty of / Geography, Department of / Graduate
189

Caracterización del delta-conjunto normal a conjuntos de subnivel de funciones convexas

Svensson Graan, Anton Kristoffer January 2015 (has links)
Ingeniero Civil Matemático / Sea $X$ un evtlc y $\Phi$ una función convexa, semicontinua inferior y propia en $X$. Dados $\lambda\in\R$ y $\delta\geq 0$, se prueba que para $\overline{x}\in S_\lambda:=[\Phi\leq\lambda]$ se cumple la fórmula \begin{equation} N^\delta_{S_\lambda}(\overline{x})=\sigma^*-\limsup_{\substack{\mu(\epsilon-\Phi(\overline{x})+\lambda)\to \delta \\ \mu\geq 0}}\mu\partial_\epsilon\Phi(\overline{x}), \label{sis} \tag{$\star$} \end{equation} sin necesidad de condiciones de calificación. En espacios de Banach, se recupera una fórmula para el cono normal que involucran el subdiferencial de Fenchel exacto, pero en puntos cercanos a $\overline{x}$. En el caso que el punto $\overline{x}$ satisfaga la condición de calificación de Slater, se extiende la validez de fórmulas conocidas en espacios de Banach a los evtlc. Se analiza el caso del cono normal a una intersección finita de conjuntos de subnivel. Se estudia qué es el lado derecho de \eqref{sis} en el caso que $\overline{x}\notin S_\lambda$ y $S_\lambda\neq\phi$, y el caso $S_\lambda=\phi$, para $\delta=0$. Por polaridad se muestra una caracterización del cono tangente a $S_\lambda$, cuando $\lambda=\Phi(\overline{x})$. Se ve una condición necesaria y suficiente de optimalidad para un problema de optimización convexa. Por último, por medio de \eqref{sis}, se muestra la semicontinuidad exterior de un operador, y se utiliza este hecho para probar una propiedad asintótica de un sistema dinámico de segundo orden que involucra al operador.
190

Levels of Polycyclic Aromatic Hydrocarbons (PAHs) in marshy soils and sediments within Warri and its environs, Negeria

Bayowa, Adejoke Victoria 11 1900 (has links)
Marshy soil and sediment samples were collected during dry and rainy seasons within Warri, and Agbarho, 20km away as control. Levels of 16 USEPA priority Polycyclic Aromatic Hydrocarbons PAHs were determined using GC-FID. Source prediction analysis was also done. The study was in Niger Delta region, Nigeria from January to March and June to August 2012 in dry and wet seasons. Benzo(a)pyrene had highest total concentration of 3.302mg/kg and mean value of 1.651mg/kg in dry season soil samples. However, sediment samples had highest levels for total concentration of PAHs of 19.362mg/kg and mean of 4.840mg/kg for both dry and rainy seasons within Warri. PAHs concentration was higher in dry than rainy seasons for soil and sediment samples. Source prediction analysis revealed that PAHs in sediments for dry season were pyrolytic while rainy seasons were petrogenic sources. For soils, the dry season was mixed sources while the rainy season was petrogenic. / Environmental Science / M. Sc. (Environmental Science)

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