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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.
351

Morfodinâmica do Rio Aguapeí: processos e formas resultantes / Tainá Medeiros Suizu. -

Suizu, Tainá Medeiros [UNESP] 25 August 2015 (has links) (PDF)
Made available in DSpace on 2018-07-27T17:13:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-08-25. Added 1 bitstream(s) on 2018-07-27T17:16:32Z : No. of bitstreams: 1 000884827.pdf: 5504795 bytes, checksum: 418033525b0a8c4a789cfbd4bfde6d31 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A planície aluvial do Rio Aguapeí-SP caracteriza-se pela elevada frequência de meandros abandonados, os quais denotam a ocorrência de mudanças cruciais nos regimes de vazão e/ou sedimentos desse rio. Entretanto, em razão da ausência de estudos que visem compreender sua morfodinâmica, desconhece-se a escala temporal das referidas mudanças, bem como suas causas e implicações na morfologia do canal. Neste viés, o presente trabalho teve como objetivo geral identificar os ajustes ocorridos na morfologia dos meandros do Rio Aguapeí-SP em virtude da influência dos principais controles do sistema fluvial. A pesquisa teve como respaldo metodológico os princípios da Teoria Geral dos Sistemas. A avaliação das formas do perfil longitudinal deste rio foi realizada com base em sua correlação com os dados do meio físico regional; estabelecimento do perfil longitudinal de equilíbrio e; aplicação do índice RDE. Houve a constatação de três anomalias, as quais estão relacionadas à erosão diferencial e ao controle do curso d'água exercido por feições estruturais. Com o intuito de compreender a resposta geomórfica do canal perante às referidas anomalias, foi estabelecida uma análise regressiva do gradiente do vale com o índice de sinuosidade do canal, a qual demonstrou uma correlação negativa entre tais variáveis em virtude das diferenças longitudinais da composição litológica do leito do rio. Em escala de detalhe, realizou-se a quantificação das mudanças espaçotemporais ocorridas na morfologia de dois trechos específicos do rio, localizados no médio-curso superior e no baixo curso junto à foz. Observou-se que o canal sofreu grandes alterações ao longo de três cenários - 1962, 1979/1986, 2010... (Resumo completo, clicar acesso eletrônico abaixo) / The Aguapeí River floodplain, located in São Paulo state - Brazil, is characterized by high frequency of oxbow lakes, which suggest the occurrence of crucial changes in flow and sediment regimes of the river. However, due to lack of studies aiming to understand its morphodynamic, the timescale of these changes as well their causes and implications in channel morphology are unknown. In this sense, the present study aimed to identify the adjustments occurred in meanders morphology of Aguapeí River due to the influence of the main controls on fluvial system. The methodological support of the research was the principles of general systems theory. The assessment of the forms in river longitudinal profile was carried out through the correlation to the physical environment data in a regional scale; the establishment of the graded river profile and; the application of Hack index. Based on that, three anomalies were detected, which are related to the differential erosion and the channel control exerted by structural features. In order to understand the channel geomorphic response to such anomalies, a regression analysis of the valley gradient to sinuosity index was established. It showed a negative correlation between these variables due to differences in the lithological compositions of the riverbed. In detailed scale, the spatio-temporal changes in the morphology of two specific reaches of the river - in the upper-middle course and lower course next to mouth - were quantified. It was verified that the channel has undergone significant changes over three years - 1962, 1979/1986 and 2010. The causes of these changes can be both allogeneic as autogenic. Regarding the allogeneic ones, the climate was considered the main cause of channel changes... (Complete abstract click electronic access below) / FAPESP: 2013/04284-3 ; 2014/02298-0
352

Life Expectancy by Education, Income and Occupation in Germany: Estimations Using the Longitudinal Survival Method

Luy, Marc, Wegner-Siegmundt , Christian, Wiedemann, Angela, Spijker, Jeroen January 2015 (has links) (PDF)
Reliable estimates for differences in life expectancy (LE) by socio-economic position (SEP), that can be assessed in an international context and are comprehensive in terms of considering different SEP dimensions, are missing for the German population so far. The aim of the present study is to fill this gap by providing estimates for differences in LE by education, household income, work status and vocational class. The lack of national mortality data by SEP required an innovative methodological approach to estimate LE from survey data with a mortality followup. The main strengths of the method are the low demand on the data, its simple applicability and the estimation of a set of age-specific probabilities of dying. We employed the method to the German Life Expectancy Survey and estimated period life tables for 45 male and 32 female SEP subpopulations. The results show striking differences in LE across all analysed SEP indicators. Among men, LE at age 40 ranges by more than five years between the lowest and highest household income quartiles, more than six years between individuals with low and high education, around ten years across the work status groups, and almost 15 years across the vocational classes. The proportion of those who reach the classic pension age of 65 years also varies considerably, as does the remaining LE at this age. The corresponding differences among women are smaller, yet still notable. The results yield an interesting finding for the ongoing discussion about the various consequences of an increased pension age. Moreover, they provide policy-makers, doctors, researchers and public health workers with insights into Germany's most disadvantaged SEP subpopulations and the potential extent of their disadvantages in terms of longevity and mortality.
353

Quantificação do transporte longitudinal a patir de dados de concentração de sedimentos em suspensão, Tramandaí-RS

Ma, Tomas Tak Min January 2013 (has links)
A proposta deste trabalho consiste na aplicação de dados de concentração de sedimentos em suspensão, na zona de arrebentação das ondas, para quantificar o transporte longitudinal que ocorre no Litoral Norte do Estado do Rio Grande do Sul – Brasil. Os dados de suspensão foram coletados a partir de uma estrutura construída perpendicularmente à linha de praia (Plataforma de Pesca de Tramandaí). As amostragens foram feitas, de modo a cobrir a zona de arrebentação, para diferentes distâncias do fundo. Verificou-se ao longo do trabalho, que o valor médio da concentração de sedimentos em suspensão (C) em quilogramas massa por metro linear de praia, apresentou como propriedade principal, uma forte proporcionalidade com a área da seção (S), ao longo do perfil, (C(kg;m) = 3,10-4 S2 + 0,1173 S). Utilizando esta particularidade, foi proposto um modelo utilizando as equações do perfil de equilíbrio de Dean (1977) para gerar o perfil de fundo. O limite deste foi obtido pela profundidade do ponto de arrebentação, determinada através da metodologia proposta por Herbich (2000). A área foi obtida por integração da equação de Dean, entre a linha de praia e o limite da zona de arrebentação. Através da propriedade citada acima, obteve-se a concentração total de sedimento entre a linha de praia e a arrebentação. O fluxo de sedimento foi obtido pelo produto da concentração total pela velocidade de corrente obtida pela aplicação da equação de Longuet-Higgins (1970). Os dados de ondas utilizados foram obtidos a partir de previsões fornecidas pela NOAA (National Oceanic Atmospheric Administration), para o ano de 2009. Observou-se ainda, que a direção do transporte resultante foi de SW para NW, em acordo com observações geológicas. O valor encontrado foi 314.799,10 m3/ano. / The purpose of this work is the application of data of suspended sediment concentration in the breaking zone waves, to quantify the longitudinal transport that occurs on the northern coast of Rio Grande do Sul - Brazil. The data of suspended sediment were collected from a structure built perpendicular to the beach line (Fishing Platform Tramandaí). The samples were taken so as to cover the breaking zone for different distances from the bottom. It was found during the study, the mean value of the suspended sediment concentration (C) in kg weight per linear meter of sand, presented as a main property, a strong proportionality to the sectional area (S) along the profile (C (kg/m) = 3.10-4 S2 + 0,1173S). Utilizing this characteristic, we propose a model using Dean’s (1977) equations of equilibrium profile, to generate the bottom profile. The limit of this was obtained by the depth of the point of breaking, determined using the methodology proposed by Herbich (2000). The area was obtained by integrating the equation Dean between the beach line and the limit of the breaking zone. Through the property mentioned above, there was obtained a total concentration of sediment between the beach line and breaking zone. The flux of sediment was obtained by the product of total concentration and the velocity of flux obtained by applying the equation Longuets-Higgins (1970). The wave data used were obtained from forecasts provided by NOAA (National Oceanic Atmospheric Administration) for the year 2009. It was also observed that the direction of transport resulting from SW to NW, in agreement with geological observations. The value found was 314799,10 m3/year.
354

Comparison of Methods for Estimating Longitudinal Indirect Effects

January 2018 (has links)
abstract: Mediation analysis is used to investigate how an independent variable, X, is related to an outcome variable, Y, through a mediator variable, M (MacKinnon, 2008). If X represents a randomized intervention it is difficult to make a cause and effect inference regarding indirect effects without making no unmeasured confounding assumptions using the potential outcomes framework (Holland, 1988; MacKinnon, 2008; Robins & Greenland, 1992; VanderWeele, 2015), using longitudinal data to determine the temporal order of M and Y (MacKinnon, 2008), or both. The goals of this dissertation were to (1) define all indirect and direct effects in a three-wave longitudinal mediation model using the causal mediation formula (Pearl, 2012), (2) analytically compare traditional estimators (ANCOVA, difference score, and residualized change score) to the potential outcomes-defined indirect effects, and (3) use a Monte Carlo simulation to compare the performance of regression and potential outcomes-based methods for estimating longitudinal indirect effects and apply the methods to an empirical dataset. The results of the causal mediation formula revealed the potential outcomes definitions of indirect effects are equivalent to the product of coefficient estimators in a three-wave longitudinal mediation model with linear and additive relations. It was demonstrated with analytical comparisons that the ANCOVA, difference score, and residualized change score models’ estimates of two time-specific indirect effects differ as a function of the respective mediator-outcome relations at each time point. The traditional model that performed the best in terms of the evaluation criteria in the Monte Carlo study was the ANCOVA model and the potential outcomes model that performed the best in terms of the evaluation criteria was sequential G-estimation. Implications and future directions are discussed. / Dissertation/Thesis / Doctoral Dissertation Psychology 2018
355

Quantificação do transporte longitudinal a patir de dados de concentração de sedimentos em suspensão, Tramandaí-RS

Ma, Tomas Tak Min January 2013 (has links)
A proposta deste trabalho consiste na aplicação de dados de concentração de sedimentos em suspensão, na zona de arrebentação das ondas, para quantificar o transporte longitudinal que ocorre no Litoral Norte do Estado do Rio Grande do Sul – Brasil. Os dados de suspensão foram coletados a partir de uma estrutura construída perpendicularmente à linha de praia (Plataforma de Pesca de Tramandaí). As amostragens foram feitas, de modo a cobrir a zona de arrebentação, para diferentes distâncias do fundo. Verificou-se ao longo do trabalho, que o valor médio da concentração de sedimentos em suspensão (C) em quilogramas massa por metro linear de praia, apresentou como propriedade principal, uma forte proporcionalidade com a área da seção (S), ao longo do perfil, (C(kg;m) = 3,10-4 S2 + 0,1173 S). Utilizando esta particularidade, foi proposto um modelo utilizando as equações do perfil de equilíbrio de Dean (1977) para gerar o perfil de fundo. O limite deste foi obtido pela profundidade do ponto de arrebentação, determinada através da metodologia proposta por Herbich (2000). A área foi obtida por integração da equação de Dean, entre a linha de praia e o limite da zona de arrebentação. Através da propriedade citada acima, obteve-se a concentração total de sedimento entre a linha de praia e a arrebentação. O fluxo de sedimento foi obtido pelo produto da concentração total pela velocidade de corrente obtida pela aplicação da equação de Longuet-Higgins (1970). Os dados de ondas utilizados foram obtidos a partir de previsões fornecidas pela NOAA (National Oceanic Atmospheric Administration), para o ano de 2009. Observou-se ainda, que a direção do transporte resultante foi de SW para NW, em acordo com observações geológicas. O valor encontrado foi 314.799,10 m3/ano. / The purpose of this work is the application of data of suspended sediment concentration in the breaking zone waves, to quantify the longitudinal transport that occurs on the northern coast of Rio Grande do Sul - Brazil. The data of suspended sediment were collected from a structure built perpendicular to the beach line (Fishing Platform Tramandaí). The samples were taken so as to cover the breaking zone for different distances from the bottom. It was found during the study, the mean value of the suspended sediment concentration (C) in kg weight per linear meter of sand, presented as a main property, a strong proportionality to the sectional area (S) along the profile (C (kg/m) = 3.10-4 S2 + 0,1173S). Utilizing this characteristic, we propose a model using Dean’s (1977) equations of equilibrium profile, to generate the bottom profile. The limit of this was obtained by the depth of the point of breaking, determined using the methodology proposed by Herbich (2000). The area was obtained by integrating the equation Dean between the beach line and the limit of the breaking zone. Through the property mentioned above, there was obtained a total concentration of sediment between the beach line and breaking zone. The flux of sediment was obtained by the product of total concentration and the velocity of flux obtained by applying the equation Longuets-Higgins (1970). The wave data used were obtained from forecasts provided by NOAA (National Oceanic Atmospheric Administration) for the year 2009. It was also observed that the direction of transport resulting from SW to NW, in agreement with geological observations. The value found was 314799,10 m3/year.
356

Modelos não-lineares para analise de dados longitudinais

Brandão, Ana Lucia de Souza 22 July 2018 (has links)
Orientadores: Dalton Francisco de Andrade, Mauro Sergio de Freitas Marques / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica / Made available in DSpace on 2018-07-22T06:29:43Z (GMT). No. of bitstreams: 1 Brandao_AnaLuciadeSouza_M.pdf: 3267941 bytes, checksum: f8969ab3f4ea13c2a899e2a07818d32a (MD5) Previous issue date: 1996 / Resumo: Não informado / Abstract: Not informed / Mestrado / Mestre em Estatística
357

Analysis of low-level interaction events as a proxy for familiarity

Apaolaza, Aitor January 2016 (has links)
This thesis provides insight into long-term factors of user behaviour with a Web site or application using low-level interaction events (such as mouse movement, and scroll action) as a proxy. Current laboratory studies employ scenarios where confounding variables can be controlled. Unfortunately, these scenarios are not naturalistic or ecologically valid. Existing remote alternatives fail to provide either the required granularity or the necessary naturalistic aspect. Without appropriate longitudinal approaches, the effects of long-term factors can only be analysed via cross-sectional studies, ignoring within-subject variability. Using a naturalistic remote interaction data capturing tool represents a key improvement and supports the analysis of longitudinal user interaction in the wild. Naturalistic low-level fine-grained Web interaction data (from URLs visited, to keystrokes and mouse movements) has been captured in the wild from publicly available working live sites for over 16 months. Different combinations of low-level indicators are characterised as micro behaviours to enable the analysis of interaction captured for extended periods of time. The extraction of micro behaviours provides an extensible technique to obtain meaning from long-term low-level interaction data. 18 thousand recurring users have been extracted and 53 million events have been analysed. A relation of users' interaction time with the site and their degree of familiarity has been found via a remote survey. This relation enables the use of users' active time with the site as a proxy for their degree of familiarity. Analysing the evolution of extracted micro behaviours enables an understanding of how users' interaction behaviour changes over time. The results demonstrate that monitoring micro behaviours offers a simple and easily extensible post hoc approach to understand how Web-based behaviour changes over time. Results of the analysis have identified key aspects from micro behaviours that are strongly correlated with users' degree of familiarity. In the case of users scrolling continuously for short periods of time, it has been found that the speed of the scroll increased as users' become more familiar with the Web site. Users have also been found to spend more time on the Web site without interacting with the mouse. Understanding long-term interaction factors such as familiarity supports the design of interfaces that accommodate users' interaction evolution. Combining found key aspects enables a prediction of a user's degree of familiarity without the need for continuous observation. The presented approach also allows for the validation of hypothesis on longitudinal user interaction behaviour factors.
358

Participation in out-of-school activities and the socio-economic gap in children's academic outcomes

Kadar Satat, Gitit January 2015 (has links)
Social stratification research has consistently found persistent inequalities in the academic outcomes of children from different socio-economic status (SES) groups. Research in the sociology of education has shown that students from higher SES groups outperform peers from lower SES groups on various academic indicators as well as make greater academic progress when assessed at two or more separate points in time. Recent evidence from the US has also shown that participation in leisure out-of-school activities (OSA) is among the factors which may contribute to maintaining or even widening these inequalities. Similar evidence is lacking in the UK. The present research focuses on this issue by analysing the role of participation in leisure OSA in the process of reproduction of social inequalities in academic outcomes among British school-aged children. The study draws on social and cultural capital theories to address the following questions: a) Are there differences in participation in OSA among school-aged children in dissimilar SES groups?; b) Taking into account children’s SES, is participation in OSA associated with their academic outcomes?; c) Does the association between participation in OSA and children’s academic outcomes vary across different SES groups? Using data from the third and fourth sweeps of the Millennium Cohort Study (MCS), when cohort members were aged 5 and 7 years old, the research explores participation in three categories of leisure activities; a) social-group activities, b) commercial-public activities, and c) home-centred activities. Children’s academic outcomes are assessed using verbal and non-verbal standardised tests, as well as by teachers’ assessment. The study applied regression models to examine the relationships between children’s SES, participation in OSA and academic outcomes. The statistical analyses were carried out in a multilevel framework which enabled the MCS hierarchical data structure and area variations to be accounted for. The findings suggest that participation in some, but not all leisure OSA is one of the factors which contributes to socio-economic inequalities in educational outcomes among British school-aged children. This is because participation in OSA is associated with better academic performance among all students, however those in high SES groups are more likely to be exposed to such activities. After controlling for SES, gender, family characteristics, school type, absenteeism and geographical variation, there is a small to moderate positive relationship between participation in a number of different leisure OSA and 7-year-olds' academic performance. Interestingly, variations among children from different SES groups were found in the extent to which attendance at certain OSA (e.g. after-school clubs) is associated with academic development between age 5 and 7: children from lower SES who attend such activities tend to progress more academically than children from intermediate and higher SES.
359

Effects of unmatched longitudinal joints and pavement markings on the lateral position of vehicles

Manepalli Subhash, Vikranth January 1900 (has links)
Master of Science / Department of Civil Engineering / Sunanda Dissanayake / Motorists generally follow the guidance provided by the pavement markings while traveling on roads. Under certain circumstances, construction joints may be necessary in concrete pavements, which are generally designed to be coincident with the pavement markings. At some locations, however, the construction joints may not exactly match the pavement markings. These situations may create confusion in the minds of drivers, which may lead them to follow joints instead of the markings. In the absence of detailed studies on this topic, an effort was made in the present study to evaluate the effects of unmatched longitudinal construction joints and pavement markings on the lateral position of vehicles. Sites having the characteristics of unmatched longitudinal construction joints and pavement markings were identified, and detailed data were collected at one of the sites. Video camera technique was used for capturing the movements of vehicles along the test site for longer durations. The video tapes were later reduced in the laboratory to extract necessary information. The distance to the right side of the vehicles from right curb of the road, the type of vehicle, presence of vehicles in the adjacent lane, weather and light conditions, and the movement of the vehicles immediately after traversing the section of the road having unmatched longitudinal construction joints and pavement markings were the main parameters observed while reducing the data. Two surveys were also conducted for gathering the opinions of some practitioners and engineers on the issue. Statistical analyses were carried out using t-tests to evaluate if there were differences. Several comparisons were made for different types of vehicles based on various conditions. The analysis results indicated that there was a statistically significant difference between the actual and expected distances to the center-line of vehicles, implying that the lateral position of vehicles may have been affected by the joints. A model was also developed to determine the lateral position of the vehicles by considering the parameters used in the analysis. Based on the survey results and analysis of field data, it was found that the lateral position of vehicles may have been affected by the unmatched joints and pavement markings.
360

The coping strategies used over a two-year period by HIV-positive women who were diagnosed during pregnancy

Kotze, Marinda 30 November 2011 (has links)
In order to investigate the coping styles used by HIV-positive pregnant women over the first two years after diagnosis, structured interviews were conducted with 224 women at antenatal clinics in Tshwane, South Africa. The baseline interview was conducted four weeks after diagnosis during pregnancy, and three follow-up interviews were conducted postpartum. Coping was measured with an adapted version of the Brief COPE (Carver, 1997). Differences between each assessment period with regard to the different coping strategies were assessed by means of paired t-tests. Variables associated with coping were identified with mixed linear analysis. It was found that active coping was used more often than avoidant coping throughout the two-year period. The most frequently used coping strategies included acceptance, direct action, positive reframing, religion and distraction. Self-blame and out-of-control decreased substantially over time, whereas helping others increased markedly over time. Active coping was associated with low internalised stigma, low depression, high self-esteem, high positive social support, knowing someone who is HIV-positive, living above the poverty line and not receiving antiretroviral treatment. Avoidant coping was associated with low HIV-knowledge, low self-esteem, high internalised stigma, high depression as well as education below tertiary level. Recommendations for psychological support services, policy and further research are made. / Dissertation (Master of Arts)--University of Pretoria, 2012. / Psychology / unrestricted

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