• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 82
  • 27
  • 23
  • 13
  • 6
  • 4
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 191
  • 53
  • 21
  • 21
  • 14
  • 13
  • 11
  • 11
  • 11
  • 11
  • 10
  • 9
  • 9
  • 9
  • 9
  • 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.
71

[en] FANTASTIC MARGIN: THE CANON AND THE BRAZILIAN SCIENCE FICTION / [pt] FANTÁSTICA MARGEM: O CÂNONE E A FICÇÃO CIENTÍFICA BRASILEIRA

FABIANA DA CAMARA GONCALVES PEREIRA 23 May 2005 (has links)
[pt] A dissertação delineia as trajetórias de produção e crítica da literatura de ficção científica no Brasil, de meados do século XIX até hoje. O objetivo é investigar o processo de marginalização do gênero na perspectiva da constituição dos cânones da literatura brasileira, divididos, de uma maneira genérica, em duas vertentes: a erudita, que legitima a intelectualidade nacional relacionando-a à alta cultura européia; e a popular, mediada pela mesma elite intelectual, na qual os mitos da brasilidade são afirmados ideologicamente. A análise dos discursos críticos sobre a ficção científica revela esta dualidade, além de alguns dos valores, pressupostos e práticas discursivas que regulam o processo de estabelecimento do cânone no Brasil. A problematização destes parâmetros é uma das chaves para compreender a não-assimilação do gênero pelo cânone oficial que constrói politicamente a idéia de Literatura Brasileira. / [en] This thesis traces the paths of the production and criticism of science-fiction literature in Brazil from the middle of the nineteenth century to the present. The goal is to investigate the process of marginalization of the genre from the standpoint of the construction of Brazilian literary canons, roughly divided in two branches: the high canon, which legitimates the Brazilian intelligentsia by relating it to European high culture; and the popular canon, mediated by the same intellectual elite, which ideologically affirms Brazilian myths of nationality. The analysis of critical discourses about science fiction shows this duality, in addition to some of the values, assumptions and practices that regulate the processes of literary canonization in Brazil. The questioning of these parameters is a key way to understand the non-assimilation of the genre by the official canon, which politically constructs the idea of a Brazilian literature.
72

Modelagem numérica da dinâmica do manto na borda da litosfera continental em margens divergentes / Numerical modeling of mantle dynamics on the edge of the continental lithosphere in divergent margins

Edgar Bueno dos Santos 19 September 2016 (has links)
O presente trabalho tem como objetivo estudar a dinâmica do manto superior em margens continentais através do uso de modelos numéricos que simulam processos convectivos e condutivos no tempo geológico, avaliando-se como a incorporação da convecçãao no estudo da história de subsidência de margens continentais difere do resultado obtido através de modelos puramente condutivos. Como primeiros testes, foram realizadas comparações dos resultados numéricos com soluções analíticas para diferentes valores do número de Rayleigh, verificando-se a validade das soluções computacionais. Também foi feita uma análise da estabilidade da litosfera no tempo geológico para diferentes perfis de viscosidade, servindo como base para a escolha dos parâmetros reológicos do manto para os modelos no contexto de margens divergentes. A partir dos cenários numéricos que melhor reproduziram a estrutura da litosfera terrestre, novos cenários foram criados para simular a evolução térmica e isostática de margens continentais. Como exemplo, utilizou-se dados geofísicos e geológicos extraídos da literatura para a bacia sedimentar do Golfo do Leão, no sudeste da Françaa, com o objetivo de comparar a evolução geodinâmica do presente modelo numérico com outros modelos publicados na literatura. Observou-se que o efeito convectivo astenosférico preserva a estrutura térmica aquecida da margem estirada por mais tempo em comparação com o modelo puramente condutivo. Isso implica que, possivelmente, outros fatores também devem ser levados em consideração como o efeito da geometria tridimensional da margem do Golfo do Leão que pode contribuir para um aumento da subsidência da margem em relação ao modelo obtido no presente trabalho. Adicionalmente, constatou-se que a convecção mantélica pode induzir tensões na base da litosfera que a deslocam dinamicamente ao longo do tempo geológico, podendo influenciar a evolução estratigráfica das bacias sedimentares marginais. São apresentados cerca de 60 cenários geodinâmicos mostrando como a variação da estrutura reológica do manto influencia a evolução térmica da litosfera e consequentemente, a história de subsidência da margem. / This work aims to study the dynamics of the upper mantle in continental margins by using numerical models that simulate convective and conductive processes in geological time scale. It was evaluated the contribution of convection and conduction for subsidence history of sedimentary basins. As first tests, simple numerical scenarios with different Rayleigh number were compared with analytic solutions, verifying the validate of the computational solutions. These numerical experiments were followed by the analysis of the lithospheric stability in the geological time scale for different values of viscosity. These experiments were used as a base for the choice of the rheological parameters of the mantle for the models in the context of divergent margins. From the numerical scenarios that better reproduced the lithospheric structure of the Earth, new scenarios were created to simulate the thermal and isostatic evolution of continental margins. As an example, geophysical and geological data extracted from the literature for the sedimentary basin of the Gulf of Lion, Southeastern France, were compared with the results of different geodynamic models published in the literature and with the numerical scenarios obtained in the present work. We observed that the effect of the astenospheric convection preserves the thermal structure of the stretched margin for a long time in comparison with purely conductive models. This implies that, possibly, other processes must be taken into account, such as the effect of the three-dimensional geometry of the Gulf of Lion margin that may contribute to a higher subsidence of the margin than the one obtained in the present work. Additionally, it was observed that mantle convection may induce stress at the base of the lithosphere that dynamically moves it in the geological time, and may influence the stratigraphic evolution of sedimentary basins. It is presented about 60 scenarios showing how the variation of the rheological structure of the mantle is taken into account in the thermal evolution of the lithosphere and consequently in the subsidence history of the margin.
73

Margens, tecnologias de controle e (i)legibilidades : etnografia sobre a produção do estado e do comércio popular no camelódromo de Porto Alegre/RS

Soilo, Andressa Nunes January 2015 (has links)
Esta dissertação aborda a constituição do camelódromo de Porto Alegre e de suas práticas de comércio popular, em sua relação com as tecnologias de (i)legibilidade produzidas na sua relação com o Estado. Este trabalho parte de uma etnografia realizada entre os anos de 2013 e 2014, que se focou tanto nas práticas e sentidos elaborados pelos comerciantes do camelódromo, quanto nas visões dos atores representantes dos órgãos de controle e vigilância estatal. A partir da perspectiva teórica de Veena Das & Deborah Poole, destaco que o Estado e suas margens interagem de forma coprodutiva. Inspirada nesta abordagem, percebendo o camelódromo como uma “margem”, objetivo demonstrar como o Estado e a margem em questão estabelecem uma relação de produção mútua a partir de suas práticas. Utilizo-me dos conceitos de (i)legibilidade e pluralismo jurídico para compreender os limites e as mobilidades de tal interação. A partir da análise dos dados coletados, pode-se depreender que o Estado é reforçado, ao mesmo passo que redefinido, pelas atividades informais do camelódromo. Por sua vez, tal fortalecimento também acontece, na relação com o Estado no comércio popular em questão, onde as tecnologias de controle estatais estimulam redes de solidariedade a se organizarem e produzirem práticas diversas, que relacionam códigos legais e condutas locais. / This dissertation approaches the constitution of Porto Alegre’s “camelódromo” and its popular trade’s practices, in relation with (i)legibility technologies produced in its nexus with the State. This study consists in an ethnography carried out between 2013 and 2014, which focused on practices and meanings produced by camelódromo’s vendors, as in the visions of the actors that represents the organs of state control and surveillance. From the theoretical perspective of Veena Das & Deborah Poole, I emphasize that the State and its margins interact in a coproductive way. Inspired by this approach, perceiving camelódromo as a margin, my purpose is to demonstrate how the State and the margin in question establish a mutual relation of production from their practices. I use, in this work, the concepts of (i)legibility and legal pluralism to understand the limits and mobilities of such interaction. From the analysis of the collected data, it is possible to deduce that the State is reinforced and redefined by camelódromo’s informal activities. In turn, this strengthening also happens between the relation of the State and popular trade in question, where State’s control technologies stimulate solidarity networks to organize and produce themselves various practices that relates legal codes and local behavior.
74

Barcelone, Marseille et Naples, territoires du picaro urbain : modéliser un discours littéraire de la marge / Barcelona, Marseille and Naples, territories of the picaro urbain : modelling a literary speech of the margin

Riberi, Erika 23 November 2018 (has links)
Cette thèse a pour objet, à partir d’une réflexion sur la littérature romanesque produite sur Barcelone, Marseille et Naples depuis 1975, la définition d’un certain type de personnage utile et pertinent pour écrire littérairement l’espace urbain contemporain dans le contexte épistémologique particulier de « l’âge postmoderne ». Dans un va-et-vient constant entre critique et théorie, la thèse se donne pour but de définir les caractéristiques, fonctions et effets spécifiques du « picaro urbain », personnage de la marge par excellence. Elle s’intéresse également, à partir de cette réflexion générale établie à partir d’une perspective locale et régionale, aux discours particuliers qu’ont pu produire les écrivains sur Barcelone, Marseille et Naples par le biais de ce type de personnage. En cela, la thèse s’inscrit aussi dans une perspective interdisciplinaire, en s’intéressant aux autres discours formulés sur ces trois villes,qu’ils soient scientifiques, artistiques, performatifs ou quotidiens. / Barcelona, Marseille and Naples, territories of the picaro urbainModelling a literary speech of the marginConsidering the novelistic production on Barcelona, Marseille and Naples since 1975, thiswork aims to define a type of character who is useful to write literarily the contemporaryurban space in the specific epistemological context called “the postmodern age”. Comingand going from criticism to theory, this thesis defines the main characteristics, functions andspecific effects of the so-called “picaro urbain”. He/she reveals himself/herself to be theprotagonist of the margin “par excellence”. Given this general reflection first made about alocal and regional perspective, this work is also interested in the specific speeches producedby the writers on Barcelona, Marseille and Naples through this kind of character. In doing so,this study also adopts an interdisciplinary perspective, looking at other speeches about thosethree cities, whether they are scientific, artistic, performative or daily.
75

Crustal structure of the northwestern continental margin of the Indian subcontinent from gravity and magnetic data

Soofi, Muhammad Asif 05 August 1991 (has links)
The continental margin off the coast of Pakistan between the Murray ridge and the Gulf of Cambay has been studied in this work using gravity, magnetic and bathymetric data. Two dimensional gravity and magnetic models based on free-air gravity and residual magnetic data are developed along a north-south profile off the coast of Karachi. The purpose was to interpret the gross crustal structure of the region. A magnetic map has also been developed for the region between latitudes 20°N and 27°N and between longitude 60°E and 70°E. The gravity model extends to a distance of about 1200 km seaward south of Karachi. The seaward end of the gravity model is constrained by seismic refraction data which suggest the presence of typical oceanic crust. The Moho depth at this end of the profile is about 12 km. At the landward end of the profile A-A' the Moho depth is not constrained by seismic data. The gravity model suggests 27 to 17 km as the possible range of the depth of the Moho and a gradual thinning of the crust from land to sea. In addition, the gravity models as interpreted in this study show grabens at the distances of 350 and 450 km along the profile. If the graben-like structures are rift grabens formed during the rifting of India from Africa then transitional crust can be expected to extend to the 500 km mark along the profile A-A'. Two dimensional models for the magnetic data along the profile were also developed. These anomalies can be interpreted as due to oceanic crust or magnetic bodies embedded in transitional crust. The possibility that the observed magnetic anomalies are due to oceanic crust has been studied in detail in this work. The location of the observed magnetic anomalies with respect to marine magnetic anomaly (28) observed earlier on the Indian Ocean floor, were compared to a marine magnetic time scale. To get a reasonable correlation between the observed and theoretical anomalies requires a considerable amount of adjustment in the spreading rate of individual magnetic blocks. Also on the magnetic map the trend of the lineation of these anomalies is perpendicular to the continental margin instead of being parallel to the continental margin as expected for a rifted continental margin. The presence of horst-and-graben structures in the inland region suggests the rifted nature for the continental margin off Karachi than the sheared nature. This indicates that the lineations should be parallel to the margin. But the magnetic lineations are perpendicular to the continental margin and if they are from oceanic crust then they would suggest that the margin is a sheared margin, which contradicts the extensional structures observed inland. This makes it very unlikely that the source of these anomalies is oceanic crust. However, it is quite possible that the magnetic lineations observed in the map were parallel to the continental margin initially but later on the continent rotated clockwise along a fault landward of the magnetic lineation. This rotation is perhaps responsible for making the lineation perpendicular to the continental margin. One objective of this study was to locate the continent-ocean boundary, but with the available amount of data it is not possible to decide on the most appropriate source for the observed magnetic anomalies. Hence it was not possible to decide exactly on the location of continent-ocean boundary. However, on the basis of gravity and magnetic data it can be said that the continent-ocean boundary lies at a distance of 500 km or greater along the profile. / Graduation date: 1992
76

Frequency response function analysis of the equatorial margin of Brazil using gravity and bathymetry

Macario, Ana L. G. 28 July 1989 (has links)
The overall objective of this study is to address questions concerning the long-term mechanical strength of the lithosphere across the equatorial margin of Brazil. The approach used in this study consists of calculating the frequency response function estimates, also called admittance, using gravity and bathymetry data. These experimental estimates are then compared to theoretical admittance curves for Airy and thin elastic plate models for which estimates on the flexural rigidity or, equivalently, effective elastic thickness may be made. Twelve profiles, each 256 km long, were extracted from gridded gravity and bathymetry data (data sources: project EQUANT, Defense Mapping Agency, National Geophysical Data Center files and GEOS 3/SEASAT altimeter data). Three profiles were specifically used for testing truncation errors introduced by four different data treatment procedures (before Fourier transforming the data) : detrending, applying 10% cosine tapering, mirror imaging and the use of the first derivatives. The method I adopted is similar to the one used by McNutt (1983) and consists of testing how reliably a given admittance estimate can be recovered as a function of the data treatment procedure. A "predicted" gravity anomaly was obtained by convolving each bathymetric profile with a theoretical admittance filter. The edges of this anomaly are then submitted to the same treatment as the corresponding bathymetric profile before Fourier transforming both profiles and calculating admittance. The stability of the long-wavelength admittance estimates, in the presence of noise, was also investigated by introducing Gaussian noise, in the range of -50 to +50 mGals, in the "predicted" gravity signal. The results indicate that relatively unbiased long-wavelength admittance estimates can be obtained by using the first derivative of the data sets. In addition, it is shown that the mirroring technique, used in previous admittance studies across Atlantic-type margins, leads to overestimated admittance values and, therefore, overestimated flexural rigidities. Neither the theoretical curves for the Airy model nor the plate flexure model can explain the experimental admittance estimates. Not only are the experimental admittance estimates higher than the predicted values but they also have a narrower peak than the theoretical curves. This raises the question of the applicability of highly simplified isostatic models for tectonic provinces such as Atlantic-type continental margins. The following reasons may explain the discrepancies between the experimental and theoretical admittance estimates: (1) The abrupt nature of the transition between oceanic and continental crust controlled by the Romanche Fracture Zone - Unlike the eastern North American continental margin which was formed as a result of extensive rifling and pulling apart, the obliquely-rifled equatorial margin of Brazil has undergone a complex tectonic evolutionary process, where additional components such as shear and right-lateral wrenching were present. Therefore, representing the margin as a thin homogeneous elastic plate might be reasonable when the transition is gradual (for which the uniform flexural rigidity assumption seems reasonable) but is probably not a good approximation when it is as abrupt as the equatorial margin of Brazil (2) Presence of subsurface loads - Previous studies have shown that estimates of the average flexural rigidity of continental lithosphere using the admittance approach are biased when subsurface loads are present. In principle, the proximity of the Romanche Fracture Zone and associated volcanism suggest that shallow buried loads, caused by intrusive bodies, might be present in the area. This could partially account for the mismatch between theoretical curves and experimental admittance estimates. (3) "Masked" estimates - The admittance estimates presented here are likely to reflect the combination of two different signals: one related to the compensation of the Barreirinhas/Piaui-Camocim sub-basin which has no topographic/bathymetric expression and the other one related to the topography/bathymetry and its compensation which is of interest in the admittance studies. Since the wavelengths of these signals do not differ by much (around 80-100 km for the basin) it is possible that in the averaging process some overlapping occurs. The combination of these signals could yield anomalous results masking the admittance estimates in the diagnostic waveband. In addition, I present a two-dimensional cross section obtained by forward modelling the gravity anomaly along a profile using the line integral method. The uniform sedimentary infill of the Barreirinhas/Piaui-Camocim basin is enough to account for the gravity low over the inner shelf and no Moho topography is required. A plausible explanation for this "rootless" basin structure is that the lithosphere is capable of supporting the sediment infill load, and thus, has finite flexural rigidity (basin is locally uncompensated). / Graduation date: 1990
77

Mapping surficial geologic habitats of the Oregon continental margin using integrated interpretive GIS techniques

Romsos, Christopher G. 29 January 2004 (has links)
We map the regional physiography and surficial lithology (Surficial Geologic Habitat or SGH) over the continental margin of Oregon. This thesis develops, describes, and implements an iterative interpretive method to map seafloor habitat types from disparate geological and geophysical datasets including: bathymetric images, sidescan sonar images, seismic reflection profiles, sediment samples, geologic maps of structure, and observations from submersibles. An indirect technique for the assessment of map accuracy or habitat type misidentification error is also explored and used to derive supplemental maps of varying interpretative confidence, or "quality". The geological and geophysical datasets used to produce the SGH maps of the Oregon margin are by their nature patchy, and form an irregular mosaic of variable data density and quality. Uniform sampling of continental margins does not yet exist, thus these maps are an attempt to glean as much information as possible from the framework of existing data. In any given area the quantity and quality of data available varied considerably, and required a flexible method of interpretation based on this availability. The integrated interpretative GIS techniques are developed to facilitate mapping geologic habitat types over this region of discontinuous and patchy seafloor data. The SGH map and thematic map accuracy assessment support improved habitat-based inventory and assessment methods. They also serve as habitat reference materials for marine resources management and planning activities at local to national scales. SGH and data quality maps are incorporated as thematic layers within a broader habitat geodatabase for west coast groundfish and are directly applied for modeling Essential Fish Habitat (EFH) for these species. / Graduation date: 2004
78

The Effect of Electoral Security on Partisan Support

Webb, Brian Michael 03 May 2007 (has links)
I examine the relationship between the electoral security of congressmen, measured as vote margins in the previous election, and the support Members of Congress offer to their party. I develop a theory that predicts safe members will be more willing to support than vulnerable members and leaders demand more loyalty from safe members than vulnerable. This arrangement is rational and beneficial for leaders and both types of members. Using an OLS regression, I find basic support for my theory.
79

Optical Contrast Agents to Visualize Molecular Expression in Breast Cancer

Langsner, Robert 16 September 2013 (has links)
Breast cancer is the second leading cause of death of women in the United States. Improvements in screening technology have increased the breast cancer incidence rate, as smaller lesions are being detected. Due to the small size of lesions, patients can choose to receive breast conservation therapy (BCT) rather than a modified radical mastectomy. Even though the breast retains cosmesis after BCT, there is an increased risk of the patient having residual microscopic disease, known as positive margins. Patients with positive margins receive increased radiation and have an increased chance of second surgery. Pathology with hematoxylin and eosin (H&E) remains the gold standard for diagnosing margin status in patients. Intraoperative pathology has been shown to reduce the rate of positive margins in BCT. However, a minority of surgery centers have intraoperative pathology centers, limiting the number of patients that receive this standard of care. The expression profiles of surface receptors such as ErbB2 (HER2-positive) and epidermal growth factor receptor (EGFR) provide information about the aggressiveness of a particular tumor. Recent research has shown that there was elevated EGFR expression in patients with a local recurrence even though the biopsies were assessed to be disease free using standard H&E. If the physicians had known the molecular expression of these biopsies, a different treatment regimen or excision of more tissue might have prevented the recurrence. This thesis investigates targeted molecular contrast agents that enhance the visualization of molecular markers such as glucose transporters (GLUTs) and growth factor receptors in tissue specimens. First, application of 2-NBDG, a fluorescent deoxy-glucose, enhances signal in cancerous tissue with a 20-minute incubation. Then, antibody functionalized silica-gold nanoshells enhance the visualization of ErbB2 overexpression in specimens with a 5-minute incubation. To image these contrast agents in cancerous tissue, a portable, inexpensive device was developed as a tool to help physicians visualize expression of surface markers. The system visualizes absorbance from nanoshell aggregates and fluorescence in the visible and near-infrared light spectrum. This study represents the first step in the development of an intraoperative optical imaging device to enhance the visualization of molecular markers overexpressed in cancerous cells.
80

The Effect of Electoral Security on Partisan Support

Webb, Brian Michael 03 May 2007 (has links)
I examine the relationship between the electoral security of congressmen, measured as vote margins in the previous election, and the support Members of Congress offer to their party. I develop a theory that predicts safe members will be more willing to support than vulnerable members and leaders demand more loyalty from safe members than vulnerable. This arrangement is rational and beneficial for leaders and both types of members. Using an OLS regression, I find basic support for my theory.

Page generated in 0.0478 seconds