Categorical data analysis using a skewed Weibull regression model

In this paper, we present a Weibull link (skewed) model for categorical response data arising from binomial as well as multinomial model. We show that, for such types of categorical data, the most commonly used models (logit, probit and complementary log-log) can be obtained as limiting cases. We further compare the proposed model with some other asymmetrical models. The Bayesian as well as frequentist estimation procedures for binomial and multinomial data responses are presented in details. The analysis of two data sets to show the efficiency of the proposed model is performed

Clinical Forms of Chikungunya in Gabon, 2010

Chikungunya fever (CHIK) is a disease caused by a virus transmitted to humans by infected mosquitos. The virus is responsible for multiple outbreaks in tropical and temperate areas worldwide, and is now a global concern. Clinical and biological features of the disease are poorly described, especially in Africa, where the disease is neglected because it is considered benign. During a recent CHIK outbreak that occurred in southeast Gabon, we prospectively studied clinical and biological features of 270 virologically confirmed cases. Fever and arthralgias were the predominant symptoms. Furthermore, variable and distinct clinical pictures including pure febrile, pure arthralgic and unusual forms (neither fever nor arthralgias) were detected. No severe forms or deaths were reported. These findings suggest that, during CHIK epidemics, some patients may not have classical symptoms (fever and arthralgias). Local surveillance is needed to detect any changes in the pathogenicity of this virus

Regressão de dados binários : distribuição Weibull

In this work a new class of models for binary data based on Weibull distribution is introduced. A review is made of the most known linkage functions. This class of models has as special case the complementary log-log model and approximates well the logit and probit models. Three real data sets are given to compare the proposed model with many others. In one of these data sets the model is extended to allow multinomial data, that is, a discrete variable with more than two outcomes. The results are very good, because the estimation of parameters is quite simple and the model has shown to be very eficient.Financiadora de Estudos e ProjetosNeste trabalho propõe-se um novo modelo, para conjunto de dados com variável resposta binária, baseado na função densidade acumuladaWeibull. Apresenta- se um resumo das funções de ligação mais conhecidas da literatura. Esta classe de modelos possui como caso especial o modelo complementar log-log e boas aproximações aos modelos logístico e probito. Três conjunto de dados reais são utilizados para comparar o modelo proposto com vários outros modelos. Em um dos conjuntos de dados o modelo _e expandido para suportar variável resposta multinomial, isto _e, variável discreta com mais de dois eventos de interesse. Os resultados obtidos são muito bons, pois a estimação dos parâmetros _e razoavelmente simples e o modelo mostrou-se extremamente eficientes

Using TDR to estimate hydraulic conductivity and air entry in growing media and sand

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Le Pléistocène supérieur marin (Tyrrhénien) en Crète nord-orientale (Grèce) / The Marine Upper Pleistocene (Tyrrhenian) in north-eastern Crete (Greece)

Abstract Coastal regions in north-eastern Crete offer numerous outcrops of Tyrrhenian formations. Their study reveals sediments corresponding to three main high sea stands during the last interglacial with intercalations of aeolianite. The three transgressions are correlated with isotope stages 5.5 (125 ka), 5.3 (120 ka) and 5.1 (80 ka). Strombus bubonius Imk, the index fossil of the Tyrrhenian, is present in the two earlier deposits. During the marine episodes, rapid sea level variations are evidenced by vermetid coatings on more deep fades sediments and by notches in the underlying bedrock. The Tyrrhenian stratigraphy of Crete throws a new light on Tyrrhenian stratigraphy of the Peloponese where references to the Eutyrrhenian and Neotyrrhenian are frequent in the the literature. The outcrops attributed to the second show the same morphostratigraphic features as those of the second Cretan transgression and, consequently, can be attributed to the 5.3 isotope stage.Résumé Le littoral de la Crète nord-orientale est riche en formations marines attribuables au Tyrrhénien. Leur étude a permis de mettre en évidence trois hauts niveaux marins principaux au cours du dernier interglaciaire séparés par des phases de développement d'éolianites. Ces trois transgressions sont rapprochées des stades isotopiques 5.5 (125 ka), 5.3 (100 ka) et 5.1 (80 ka) ; les dépôts des deux premières renferment Strombus bubonius Lmk, le fossile directeur du Tyrrhénien. Les altitudes relatives des littoraux correspondants impliquent des variations du taux de surrection des mouvements verticaux. Au cours de ces épisodes transgressifs des variations rapides du niveau de la mer sont repérées par des placages de vermets sur des sédiments de faciès plus profonds et par des encoches sur le substratum. La stratigraphie du Tyrrhénien crétois éclaire celle du Tyrrhénien du Péloponnèse longtemps distribué en Eutyrrhénien et Néotyrrhénien. Les sites attribués à ce dernier en Élide et en Laconie présentent les caractéristiques morphostratigraphiques du deuxième épisode crétois et appartiendraient donc au stade isotopique 5.3.Kéraudren Bertrand, Dalongeville Rémi, Bernier Paul, Caron Vincent, Renault-Miskovsky Josette. Le Pléistocène supérieur marin (Tyrrhénien) en Crète nord-orientale (Grèce) / The Marine Upper Pleistocene (Tyrrhenian) in north-eastern Crete (Greece). In: Géomorphologie : relief, processus, environnement, Juillet-septembre, vol. 6, n°3. pp. 177-190

Trottoirs de corrosion étagés d'âge tyrrhénien (stade 5.1) à Malia

International audienceLa falaise de Malia a conservé des témoins morphologiques et stratigraphiques des deux dernières transgressions du stade isotopique 5 (5.3 et 5.1). Ces témoins permettent de dater une activité tectonique contrastée pendant le stade 5.1 : des trottoirs de corrosion étages s'expliquent par une surrection saccadée, le plan incliné inférieur tapissé de vermétidés s'expliquant, lui, par une surrection ultérieure plus douce et plus progressiv

Indices morphologiques de microvariations de la ligne de rivage pendant la transgression du stade 5.1 (Pléistocène supérieur) : le site des Charniers à Malia (Crète septentrionale). Résumés

Colloque de Paris, 5-6 novembre 199

Trottoirs de corrosion étagés d'âge tyrrhénien (stade 5.1) à Malia, Crète / Stepped corrosion benches of Tyrrhenian age (stade 5.1) in Malia, Crete

Abstract Morphologic and stratigraphie remnants of the two latest transgressions ofisotopic stage 5 (5.3 et 5.1) are preserved on the cliff of Malia. They allow the dating of a contrasted tectonic activity during isotop stage 5.1 : first, stepped corrosion benches were provoked by a swift jerky surrection; later, the shaping of a lower incline plane covered with Vermetids was made during a more gentle and progressive surrection.Résumé La falaise de Malia a conservé des témoins morphologiques et stratigraphiques des deux dernières transgressions du stade isotopique 5 (5.3 et 5.1). Ces témoins permettent de dater une activité tectonique contrastée pendant le stade 5.1 : des trottoirs de corrosion étages s'expliquent par une surrection saccadée, le plan incliné inférieur tapissé de vermétidés s'expliquant, lui, par une surrection ultérieure plus douce et plus progressive.Dalongeville Rémi, Kéraudren Bertrand, Bernier Paul, Renault-Miskovsky Josette. Trottoirs de corrosion étagés d'âge tyrrhénien (stade 5.1) à Malia, Crète / Stepped corrosion benches of Tyrrhenian age (stade 5.1) in Malia, Crete. In: Géomorphologie : relief, processus, environnement, Janvier-mars, vol. 6, n°1. pp. 21-24

Le Pléistoscène supérieur marin (Tyrrhénien) en Crète nord-orientale (Grèce)

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