[pt] O objetivo desta pesquisa é propor um modelo estatístico que possa estimar a probabilidade de ocorrência de falências ou concordatas em empresas de Internet. Após as recentes e drásticas perdas de capital em investimentos nas empresas desta nova indústria, instituições financeiras, pessoas físicas e todos os investidores desejam ter o conhecimento da real situação financeira das empresas denominadas pontocom. Esta pesquisa selecionou empresas norte-americanas que pediram falência ou concordata nas Cortes Norte-Americanas de Falências,entre 1999 e 2001, e empresas que não o fizeram, por amostragem de conveniência, que possuem ações listadas em bolsa e operam no e-commerce, isto é que vendem seus produtos ou serviços através da Internet. Utilizou, ainda, as demonstrações financeiras destas empresas para identificar, por intermédio de um teste T de amostras independentes, as variáveis mais significantes na discriminação dos dois grupos de empresas observados na amostra: o de empresas falidas e o de não-falidas. Analisadas as distribuições estatísticas das variáveis,o modelo de regressão logística demonstra ser o mais apropriado à pesquisa, por não possuir a premissa de normalidade multivariada. A conclusão final da pesquisa é a proposição de um modelo estatístico que indica a probabilidade de uma empresa de Internet falir ou não, com índice R2 de Nagelkerke de 0,887, percentual máximo de acerto na classificação de 97,4 por cento e que utiliza ainda não utilizadas em pesquisas anteriores similares. / [en] The objective of this research is to propose a statistical model that could estimate the probability of occurrence of bankruptcy for Internet companies. After the recent and drastic losses of investment capital in companies in this new sector of the economy, financial institutions, individuals and all investors wish to know the real financial position of these companies called dotcom. This research selected American companies that have filed a petition under the United States Bankruptcy Code, between 1999 and 2001, and companies which have not done it, by convenience sampling, that list their shares on stock markets and operate in e-commerce, i.e. companies that sell their products or services through the Internet. The financial statements of these companies were also used to identify,by analyzing a T test of independent samples, the most significant variables for discriminating the two observed groups in the sample: the bankrupt and the nonbankrupt companies. After analyzing the variables statistical distributions, a logistic regression model revealed to be the more appropriate for the research, for not having the multivariate normality assumption. The conclusion of this research proposes a statistical model which indicates the probability of an Internet company becoming bankrupt or not, with a Nagelkerke R Squared of 0,887, and an overall percentage of correct prediction of 97,4 percent. The model uses several variables not previously included in similar previous financial difficulties prediction models.

The microbial communities found in soils are inherently heterogeneous and often exhibit spatial variations on a small scale. Becker et al. (2006) investigate this phenomenon and present statistical analyses to support their findings. In this project, alternative statistical methods and models are considered and employed in a re-analysis of the data from Becker. First, parametric nested random effects models are considered as an alternative to the nonparametric semivariogram models and kriging methods employed by Becker to analyze patterns of spatial variation. Second, multiple logistic regression models are employed to investigate factors influencing microbial community structure as an alternative to the simple logistic models used by Becker. Additionally, the microbial community profile data of Becker were unobservable at several points in the spatial grid. The Becker analysis assumes that the data are missing completely at random and as such have relatively little impact on inference. In this re-analysis, this assumption is investigated and it is shown that the pattern of missingness is correlated with both metabolic potential and spatial coordinates and thus provides useful information that was previously ignored by Becker. Multiple imputation methods are employed to incorporate the information present in the missing data pattern and results are compared with those of Becker.

Submitted by Viviane Lima da Cunha (viviane@biblioteca.ufpb.br) on 2017-06-16T12:44:17Z No. of bitstreams: 1 arquivototal.pdf: 1568113 bytes, checksum: 143c994d6a632a3c81bc4c4e5d8557f6 (MD5) / Made available in DSpace on 2017-06-16T12:44:17Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1568113 bytes, checksum: 143c994d6a632a3c81bc4c4e5d8557f6 (MD5) Previous issue date: 2017-02-24 / Diabetic macular edema (DME) is the main cause of visual impairment in patients with diabetes mellitus. The most widely used treatment today is intravitreal injection (IIV) of anti-VEGF (vascular endothelial growth factor). Optical coherence tomography (OCT) is the gold-standard diagnostic test, however it is expensive and inaccessible. Some risk factors are strongly associated with development of DME and its response to treatment. There is few surveys that analyzes the impact and risk percentages of these factors in the probability of developing EMD and, therefore, in the necessity of early therapeutic intervention, which motivated the accomplishment of this research. This study aimed to achieve a Predictive Model to guide the decision in the early treatment with intravitreal injection in patients with EMD, by quantifying and ranking the risk factors impact on the chance of a diabetic patient need this therapy. It is a cross-sectional, observational, descriptive and analytical study. The data were collected at the Ophthalmology Department of the Lauro Wanderley University Hospital - UFPB and at the Hospital Visão, both in João Pessoa, and at the Genival Barbosa de Lucena Vision Center, located in Guarabira-PB, from July 2015 to September 2016. Individuals with type 1 or 2 diabetes and older than 18 years were included, after signing the informed consent form. The logistic regression model was used to obtain and adapt the predictive model and all the data were analyzed in statistical software R®, version 3.2.0. Eighty diabetic patients were evaluated: 57.5% had no indication of IIV and 42.5% needed this treatment. Of those who had EMD and needed anti-VEGF injection, the mean age was 60.65 years, 47.05% male and 52.94% female. In the group without macular edema, the mean age was 58.02 years, 26.06% male and 73.91% female. Among the individuals who had no indication of intravitreal injection of anti-VEGF, most had no mild retinopathy or non-proliferative diabetic retinopathy (NPDR) (69.56%). Among the patients who needed the treatment, the majority had severe NPDR or proliferative retinopathy (79.41%). Were identified as risk factors to EMD and intravitreal anti-VEGF: be retired (OR = 5.22, p-value0.05), had a personal history of diabetic retinopathy (OR = 20.27; P-value 0.006) and positive history for previous treatment with anti-VEGF (OR = 23.23; p-value 0.002). From the results of this study, we conclude that a diabetic individual has low visual acuity and presents these three factors, should be referred as soon as possible to the specialist, since he has a risk of presenting DME with need for anti-VEGF IIV, with 91.17% of accuracy. In summary, an evaluative and predictive model was proposed to serve as a supporting tool in therapeutic decision, mainly to the non-retinal physician, to refer to the specialist the patients with diabetic retinopathy and its main cause of low visual acuity - diabetic macular edema - to early diagnosis and treatment, which may be decisive to preventing irreversible visual loss in these patients. / A injeção intravítrea (IIV) de anti-VEGF (fator de crescimento vascular endotelial) constitui a modalidade terapêutica mais utilizada nos dias de hoje para o tratamento do edema macular diabético (EMD), sendo esta a principal causa de baixa visual em pacientes portadores de diabetes mellitus. O exame padrão – ouro para o diagnóstico é a tomografia de coerência óptica (TCO) da mácula, no entanto possui alto custo e difícil acesso. O desenvolvimento de EMD e a resposta ao tratamento são fortemente associados a determinados fatores de risco. Na literatura especializada há uma escassez de estudos que estabeleçam uma quantificação dos percentuais de risco desses fatores, a fim de verificar aqueles que possuem maior impacto na probabilidade de desenvolver EMD e, portanto, na necessidade de intervenção terapêutica precoce, o que motivou a realização desta pesquisa. O estudo teve por objetivo a propositura de um Modelo Preditivo para auxiliar na decisão de realização de uma injeção intravítrea de anti-VEGF, a partir da quantificação e hierarquização dos fatores de risco que compõem o perfil dos indivíduos adultos diabéticos. Trata-se de um estudo transversal, observacional, descritivo e inferencial. Os dados foram coletados na Unidade da Visão do Hospital Universitário Lauro Wanderley – UFPB e no Hospital Visão, ambos em João Pessoa, e no Centro da Visão Genival Barbosa de Lucena, localizado na cidade de Guarabira-PB, no período de julho de 2015 a setembro de 2016. Foram incluídos indivíduos com diabetes tipo 1 ou 2 e idade acima de 18 anos, após assinatura do termo de consentimento livre e esclarecido. O modelo de regressão logística foi utilizado para obtenção e adequação do modelo preditivo e todos os dados foram analisados no software estatístico R®, versão 3.2.0. Foram avaliados 80 pacientes diabéticos, dos quais 57,5% não tiveram indicação de IIV e 42,5% receberam indicação do tratamento em questão. Dos que tiveram EMD e indicação do tratamento com injeção de anti-VEGF, a média de idade foi de 60,65 anos, sendo 47,05% do sexo masculino e 52,94% do sexo feminino. Em relação àqueles sem edema macular, a média de idade foi de 58,02 anos, sendo 26,06% do sexo masculino e 73,91% do sexo feminino. Dentre os indivíduos que não tiveram indicação de injeção intravítrea de anti-VEGF, a maioria apresentou ausência de retinopatia ou retinopatia diabética não- proliferativa (RDNP) leve (69,56%). Já dentre os pacientes que necessitaram do tratamento, a maioria apresentou RDNP severa ou retinopatia proliferativa (79,41%). Foram identificados como fatores de risco para o edema macular diabético e, portanto, necessidade de IIV, o indivíduo ser aposentado (OR=5,22; p-valor0,05), ter histórico pessoal de retinopatia diabética (OR=20,27; p-valor 0,006) e histórico positivo para tratamento prévio com anti-VEGF (OR=23,23; p-valor 0,002). Concluímos, a partir dos resultados desta pesquisa, que um indivíduo diabético tenha baixa visual e apresente esses três fatores, deve ser encaminhado o quanto antes ao especialista, pois possui risco de apresentar EMD com necessidade de IIV de anti-VEGF, com 91,17% de acerto. Em suma, foi proposto um modelo de avaliação e de predição para servir como ferramenta coadjuvante na tomada de decisão, sobretudo do médico não-retinólogo, a fim de encaminhar para o diagnóstico e tratamento precoces os pacientes com retinopatia diabética e sua principal causa de baixa acuidade visual – o edema macular diabético –, o que pode ser decisivo na prevenção da perda visual irreversível nesses pacientes.

No description available.

Turnouts are an important part of railway infrastructure for two reasons: infrastructure andmaintenance. For the infrastructure they provide the flexibility to allow the formulation and branchingof railway network and for maintenance they consume a large part of maintenance budget and have aprominent place in maintenance planning policy and activities. This is because as a “mechanical object”,a turnout often experiences malfunctions. The problem becomes even more complicated, since a turnoutis composed of many different parts and each of them fails for very different reasons (e.g. switch bladesvs crossing part). This is reflected in the different needs for maintenance activities, as railways areforced to pour in excessive amounts of resources to carry out emergency repairs, or to carry outunnecessary scheduled maintenance works in turnouts, which do not need to be inspected or repaired.Therefore, it is difficult to plan and organize maintenance activities in turnouts in an efficient manner.This raises the question of whether malfunctions in turnouts can be predicted and used as informationfor the maintenance planning process in order to optimize it and develop it into a more reliablepreventive maintenance planning.The aim of this analysis is to attempt to model the probability of various malfunctions in turnouts asa function of their main geometric and operational characteristics by using logistic regression modelsand then input these results into the maintenance planning process in order to optimize it. First, it wasimportant to objectify the railway track system and the turnout components, both in terms of parts andinterrelationships. Furthermore, the process and basic elements of railway maintenance planning weredefined, as well as arguments that motivate a turn towards preventive maintenance planningmethodologies. This was done through a comprehensive literature study.The basis of this research was case studies, which described the relationship between geometricaland operational characteristics of turnouts and their wear, as well as risk-based modelling methods inrailway maintenance planning. To create the analysis model, data from turnouts in eastern regionprovided by the Swedish Transport Administration were used, both from the point of view of describingthe underlying causes of turnout malfunctions and to formulate an object-oriented database suitable forusing in logistic regression models. The goal was a logit model that calculated the malfunctionprobability of a turnout, which could be used directly into a maintenance planning framework, whichranked maintenance activities in turnouts.The results obtained showed that although the model suffers from low correlation, differentrelationships between input variables and different functional errors were established. Furthermore, thepotential of these analytical models and modeling structures was shown to be able to developpreventive, predictive railway maintenance plans, but further analysis of the data structure is required,especially regarding data quality. Finally, further possible research areas are presented. / Spårväxlar är viktiga delar av järnvägens infrastruktur av två orsaker: infrastruktur och underhåll.För infrastrukturen ger de möjlighet till flexibla tillåter de formulering och grenning av järnvägsnät ochför underhållet konsumerar de en stor del av underhållsbudgeten och de har en framträdande plats iunderhållsplaneringspolitiken och aktiviteterna. Detta beror på att som ett ”maskinellt objekt”, harspårväxeln ofta fel. Problemet blir ännu mer komplicerat, eftersom en spårväxel består av många olikadelar och var och en av dem bryts ner av mycket olika skäl (t.ex. tunganordning vs korsningsdel). Dettaåterspeglas i olika behov av underhållsaktiviteter. Eftersom järnvägarna tvingas hålla alltför storamängder resurser för att utföra akuta reparationer eller för att utföra onödiga schemalagdaunderhållsarbeten i spårväxlar, som inte behöver inspekteras eller repareras. Därför är det svårt attplanera och organisera underhållsaktiviteter för spårväxlarna på ett effektivt sätt. Detta ställer fråganom funktionsfel i spårväxlar kan förutsägas och användas som information till  underhållsplaneringsprocessen för att optimera den och utveckla den till en pålitligare förebyggandeunderhållsplanering.Syftet med denna analys är att försöka modellera sannolikheten för olika funktionsfel i spårväxlarsom en funktion av deras huvudsakliga geometriska och operativa egenskaper med användning avlogistiska regressionsmodeller och sedan mata dessa resultat in i underhållsplaneringsprocessen för attoptimera den. För det första var det viktigt att objektifiera järnvägsspårsystemet ochspårväxlarkomponenterna, både vad gäller delar och inbördes förhållanden. Dessutom definieradesprocessen och grundelementen i järnvägsunderhållsplaneringen, samt att argument som motiverarförändring till förebyggande underhållsplaneringsmetoder. Detta gjordes genom en omfattandelitteraturstudie.Grunden i denna analys var fallstudier, som beskrev förhållandet mellan geometriska ochoperationella egenskaper hos spårväxlar och deras förslitning samt riskbaserade modelleringsmetoder ijärnvägsunderhållsplanering. För att skapa analysmodellen användes data från spårväxlar i östraregionen som tillhandahölls av Trafikverket, både ur synpunkten att beskriva de underliggandeorsakerna till spårväxlarsfel och för att formulera en objektorienterad databas lämplig för användning ilogistiska regressionsmodeller. Målet var en logitmodell som beräknade sannolikheten för fel i enspårväxel, som kunde användas direkt i en underhållsplaneringsram, som rangordnar lämpigaunderhållsaktiviteter i spårväxlar.Erhållna resultat visade att även om modellen lider av låg korrelation, konstaterades olika sambandmellan ingående variabler och olika funktionsfel. Vidare visades potentialen hos dessa analysmodelleroch modelleringsstrukturer för att kunna utveckla förebyggande, förutsägbarajärnvägsunderhållsplaner, men det krävs troligtvis ytterligare analys av datastrukturen, specielltangående datakvaliteten. Slutligen presenteras ytterligare möjliga forskningsområden.

Although studies examining juvenile recidivism have focused primarily on violent recidivism, the factors that predict recidivism likely differ by offense type. To examine general, property, and violent recidivism, this study combined individual-level data (i.e., offender and case characteristics) from the Mississippi Youth Court Information Data System (MYCIDS) for the years 2009-2011 and contextual-level data (i.e., county characteristics) from the 2010 U.S. Census and the 2010 Uniform Crime Reports (UCR). Results showed that offender characteristics predicted only general and property recidivism, but case characteristics mattered for all three types (i.e., general, violent, and property recidivism). Contextual characteristics (i.e., the percentage of the population that is male aged 15 to 24) also mattered, but only for property recidivism. These findings have implications for policies and programs related to the treatment of juvenile offenders.

[pt] O objetivo da dissertação é analisar e comparar a influência de diferentes tipos de parceiros em arranjos cooperativos para projetos de PD&I sobre a apropriação de valor pelas empresas inovadoras da indústria de transformação no Brasil, considerando-se condições ambientais distintas, como nível de intensidade tecnológica e força do regime de apropriabilidade dos setores em que atuam, bem como características internas, como tamanho da empresa e capacidade para cooperar em projetos de PDeI (focalizando inovações de produto e/ou processo). A fonte de dados é a Pesquisa Nacional de Inovação (Pintec 2014), realizada pelo Instituto Brasileiro de Geografia e Estatística (IBGE). A pesquisa pode ser considerada descritiva e aplicada. A metodologia adotada compreende pesquisa bibliográfica sobre inovação; mecanismos de apropriação de valor; cooperação interorganizacional para inovação e classificações tecnológicas, destacando-se a classificação de intensidade tecnológica proposta pela Organização para a Cooperação e Desenvolvimento Econômico (OCDE); pesquisa documental referente à Classificação CNAE e ao Manual da Pintec 2014, ambas divulgadas pelo IBGE; análise de conteúdo para classificar as atividades econômicas das empresas inovadoras da indústria de transformação (respondentes da Pintec 2014), segundo quatro níveis de intensidade tecnológica e regime de apropriabilidade dos setores em que atuam e três faixas de pessoal alocado; solicitação ao IBGE de acesso aos microdados não desidentificados da Pintec 2014; e desenvolvimento de modelos econométricos logit para os doze agrupamentos de empresas, classificadas por intensidade tecnológica/força do regime de apropriabilidade do setor e por faixa de pessoal ocupado. A utilização dos microdados da Pintec 2014 para analisar a influência da cooperação interorganizacional sobre a apropriação de valor pelas empresas inovadoras da indústria de transformação no Brasil em diferentes condições ambientais conferem à pesquisa um caráter original, uma vez que os estudos anteriores baseados em Pesquisas Nacionais de Inovação não exploraram essa abordagem metodológica. / [en] This dissertation aims to analyze and compare the influence of different types of partners in cooperative arrangements for RDandI projects on the appropriation of value by innovative companies of the transformation industry in Brazil, considering different environmental conditions, such as the level of technological intensity and strength of the appropriability regime of the sectors in which they operate, as well as internal characteristics such as company size and its capacity to cooperate in RDandI projects (focusing on product and/or process innovations). The primary data source is the National Innovation Survey (Pintec), conducted by the Brazilian Institute of Geography and Statistics (IBGE). The research can be considered descriptive and applied. The methodology adopted includes bibliographic research on innovation; value creation and value appropriation mechanisms; and technological classifications, highlighting the classification of sectoral technological intensity proposed by the Organization for Economic Cooperation and Development (OECD); documentary analysis concerning the Brazilian Classification of Economic Activities (CNAE) and Pintec 2014, both published by IBGE; content analysis to classify the economic activities of the respondent companies, according to sectoral technological intensity, appropriability regime of the sectors in which they operate and number of employees; request to IBGE for access to microdata of Pintec 2014; development of logit econometric models for the companies classified by sector technological intensity/strength of the appropriability regime, and by number of employees (micro and small, medium and large companies). The use of microdata from Pintec 2014 to analyze and compare the influence of different types of partners in cooperative arrangements for RDandI projects on the appropriation of value by innovative companies under different environmental conditions give the research an original character, since previous studies based on National Innovation Surveys have not explored this methodological approach.