The zero-inflated promotion cure rate model applied to financial data on time-to-default

In this paper, we extend the promotion cure rate model studied in Yakovlev and Tsodikov (1996) and Chen et al. (1999) by incorporating an excess of zeros in the modeling. Despite relating covariates to the cure fraction, the current approach does not enable us to relate covariates to the fraction of zeros. The presence of excess of zeros in credit risk survival data stems from a group of loans that became defaulted shortly after the granting process. Through our proposal, all survival data available of customers is modeled with a multinomial logistic link for the three classes of banking customers: (i) individual with an event at the starting time (zero time), (ii) non-susceptible for the event, or (iii) susceptible for the event. The model parameter estimation is reached by the maximum likelihood estimation procedure and Monte Carlo simulations are carried out to assess its finite sample performance

An Investigation of the KFK_{F}-type Lorentz-Symmetry Breaking Gauge Models in N=1N=1-Supersymmetric Scenario

In this work, we present two possible venues to accomodate the $K_{F}$-type Lorentz-symmetry violating Electrodynamics in an $N=1$-supersymmetric framework. A chiral and a vector superfield are chosen to describe the background that signals Lorentz-symmetry breaking. In each case, the $\ K_{\mu \nu \kappa \lambda }$-tensor is expressed in terms of the components of the background superfield that we choose to describe the breaking. We also present in detail the actions with all fermionic partners of the background that determine $\ K_{\mu \nu \kappa \lambda }$.Comment: 10 page

Demanda hídrica e eficiência de irrigação pelo arroz: efeito da altura da lâmina de água.

bitstream/item/79853/1/comunicado-238.pd

A Metric Framework for quantifying Data Concentration

Poor performance of artificial neural nets when applied to credit-related classification problems is investigated and contrasted with logistic regression classification. We propose that artificial neural nets are less successful because of the inherent structure of credit data rather than any particular aspect of the neural net structure. Three metrics are developed to rationalise the result with such data. The metrics exploit the distributional properties of the data to rationalise neural net results. They are used in conjunction with a variant of an established concentration measure that differentiates between class characteristics. The results are contrasted with those obtained using random data, and are compared with results obtained using logistic regression. We find, in general agreement with previous studies, that logistic regressions out-perform neural nets in the majority of cases. An approximate decision criterion is developed in order to explain adverse results

Potencial antagônico de Trichoderma spp. originários de diferentes agroecossistemas contra Sclerotinia sclerotiorum e Fusarium solani.

A partir de 40 amostras de solo, provenientes dos estados do Rio Grande do Sul, Minas Gerais, São Paulo, Bahia, Goiás e Tocantins, uma coleção de 230 isolados monospóricos de Trichoderma spp. foi estabelecida, usando o meio seletivo TSM. Com o objetivo de selecionarem-se isolados com potencial para controle biológico de doenças, foram conduzidos testes de pareamento de culturas em meio BDA, a 20 °C para Sclerotinia sclerotiorum e a 25 °C para Fusarium solani f.sp. phaseoli. Antagonismo contra os dois patógenos foi observado em 10% dos isolados. Avaliações ao microscópio eletrônico de varredura de sete isolados selecionados in vitro mostraram que nem todos promoveram o hiperparasitismo dos patógenos, sugerindo a existência de outros mecanismos de antagonismo, como antibiose ou competição

Plasma levels of nitric oxide related amino acids in demented subjects with Down syndrome are related to neopterin concentrations

Subjects with Down syndrome (DS) have abnormalities in virtually all aspects of the immune system and almost all will be affected with Alzheimer’s disease (AD). It is thought that nitric oxide (NO) is involved in the pathophysiology of AD. In the present study, including a total of 401 elderly DS subjects, the spectrum of plasma amino acids and neopterin was investigated and related to development of AD. Concentrations of nearly all amino acids in DS subjects differed significantly from those of healthy controls. Neopterin was increased in DS subjects, especially in dementia. The production of NO as reflected by an increased citrulline/arginine ratio (Cit/Arg ratio) was enhanced during development of clinical dementia. Neopterin concentrations correlated to the Cit/Arg ratio only in the group of prevalent demented subjects (ρ = 0.48, P = 0.006). The results of this study are suggestive for an increase in oxidative processes in DS subjects with AD

Smoking-induced aggravation of experimental arthritis is dependent of aryl hydrocarbon receptor activation in Th17 cells.

Background: Epidemiologic studies have highlighted the association of environmental factors with the development and progression of autoimmune and chronic inflammatory diseases. Among the environmental factors, smoking has been associated with increased susceptibility and poor prognosis in rheumatoid arthritis (RA). However, the immune and molecular mechanism of smoking-induced arthritis aggravation remains unclear. The transcription factor aryl hydrocarbon receptor (AHR) regulates the generation of Th17 cells, CD4 T cells linked the development of autoimmune diseases. AHR is activated by organic compounds including polycyclic aromatic hydrocarbons (PAHs), which are environmental pollutants that are also present in cigarette smoke. In this study, we investigated the role of AHR activation in the aggravation of experiment arthritis induced by exposure to cigarette smoke. Methods: Mice were exposed to cigarette smoke during the developmental phase of antigen-induced arthritis and collagen-induced arthritis to evaluate the effects of smoking on disease development. Aggravation of articular inflammation was assessed by measuring neutrophil migration to the joints, increase in articular hyperalgesia and changes in the frequencies of Th17 cells. In vitro studies were performed to evaluate the direct effects of cigarette smoke and PAH on Th17 differentiation. We also used mice genetically deficient for AHR (Ahr KO) and IL-17Ra (Il17ra KO) to determine the in vivo mechanism of smoking-induced arthritis aggravation. Results: We found that smoking induces arthritis aggravation and increase in the frequencies of Th17 cells. The absence of IL-17 signaling (Il17ra KO) conferred protection to smoking-induced arthritis aggravation. Moreover, in vitro experiments showed that cigarette smoke can directly increase Th17 differentiation of T cells by inducing AHR activation. Indeed, Ahr KO mice were protected from cigarette smoke-induced arthritis aggravation and did not display increase in TH17 frequencies, suggesting that AHR activation is an important mechanism for cigarette smoke effects on arthritis. Finally, we demonstrate that PAHs are also able to induce arthritis aggravation. Conclusions: Our data demonstrate that the disease-exacerbating effects of cigarette smoking are AHR dependent and environmental pollutants with AHR agonist activity can induce arthritis aggravation by directly enhancing Th17 cell development

La investigación artística en el contexto universitario: estudio de caso en el perfil danza contemporánea

Los referentes epistemológicos de la investigación artística en los procesos de creación, desarrollados en las prácticas artísticas, del perfil Danza Contemporánea en la Universidad de las Artes de Cuba, se fundamentan a partir del estudio de la configuración de la noción investigación artística (I.A.) en el contexto universitario. El estudio se fundamenta desde los referentes teóricos que avalan el estado del arte de la cuestión y el estudio de caso, como metodología cualitativa. Su reconstrucción se realiza desde la perspectiva cultural de la investigación. Esta posibilita la comprensión de la I.A. inmersa en un entramado de relaciones establecidas por un grupo humano acerca de la investigación tanto científica como artística. Asimismo, devela al ser humano no solo como sujeto que participa en esta dinámica, sino que construye sus formas de llevarla a cabo a partir de la cosmovisión que del asunto tiene, de la configuración de la matriz epistémica que posee acerca de qué es investigación y cómo se investiga. Los referentes epistemológicos de la investigación artística en los procesos de creación, desarrollados en las prácticas artísticas, del perfil Danza Contemporánea en la Universidad de las Artes de Cuba, se fundamentan a partir del estudio de la configuración de la noción investigación artística (I.A.) en el contexto universitario. El estudio se fundamenta desde los referentes teóricos que avalan el estado del arte de la cuestión y el estudio de caso, como metodología cualitativa. Su reconstrucción se realiza desde la perspectiva cultural de la investigación. Esta posibilita la comprensión de la I.A. inmersa en un entramado de relaciones establecidas por un grupo humano acerca de la investigación tanto científica como artística. Asimismo, devela al ser humano no solo como sujeto que participa en esta dinámica, sino que construye sus formas de llevarla a cabo a partir de la cosmovisión que del asunto tiene, de la configuración de la matriz epistémica que posee acerca de qué es investigación y cómo se investiga.The epistemological references of the artistic research in the creation processes, developed in the artistic practices, of the profile Contemporary Dance in the University of the Arts of Cuba, are based on the study of the configuration of the notion artistic research (AR) in the university context. The study is based on the theoretical references that support the state of the art of the question and the case study, as a qualitative methodology. Its reconstruction is carried out from the cultural perspective of the investigation. This makes it possible to understand the AR. Immersed in a framework of relationships established by a human group about both scientific and artistic research. It also reveals the human being not only as a subject that participates in this dynamic, but also builds his ways of carrying it out from the cosmovision of the subject, from the configuration of the epistemic matrix that it possesses about what is research and how it is investigated.Tesis Univ. Jaén. Departamento Didáctica de la Expresión Musical, Plástica y Corporal. Leída el 3 de febrero de 201

A social and ecological assessment of tropical land uses at multiple scales: the Sustainable amazon network

Science has a critical role to play in guiding more sustainable development trajectories. Here, we present the Sustainable Amazon Network (Rede Amazônia Sustentável, RAS): a multidisciplinary research initiative involving more than 30 partner organizations working to assess both social and ecological dimensions of land-use sustainability in eastern Brazilian Amazonia. The research approach adopted by RAS offers three advantages for addressing land-use sustainability problems: (i) the collection of synchronized and co-located ecological and socioeconomic data across broad gradients of past and present human use; (ii) a nested sampling design to aid comparison of ecological and socioeconomic conditions associated with different land uses across local, landscape and regional scales; and (iii) a strong engagement with a wide variety of actors and non-research institutions. Here, we elaborate on these key features, and identify the ways in which RAS can help in highlighting those problems in most urgent need of attention, and in guiding improvements in land-use sustainability in Amazonia and elsewhere in the tropics. We also discuss some of the practical lessons, limitations and realities faced during the development of the RAS initiative so far