Splitting Arabic Texts into Elementary Discourse Units

International audienceIn this article, we propose the first work that investigates the feasibility of Arabic discourse segmentation into elementary discourse units within the segmented discourse representation theory framework. We first describe our annotation scheme that defines a set of principles to guide the segmentation process. Two corpora have been annotated according to this scheme: elementary school textbooks and newspaper documents extracted from the syntactically annotated Arabic Treebank. Then, we propose a multiclass supervised learning approach that predicts nested units. Our approach uses a combination of punctuation, morphological, lexical, and shallow syntactic features. We investigate how each feature contributes to the learning process. We show that an extensive morphological analysis is crucial to achieve good results in both corpora. In addition, we show that adding chunks does not boost the performance of our system

Modelling prognostic factors in advanced pancreatic cancer

Pancreatic cancer is the fifth most common cause of cancer death. Identification of defined patient groups based on a prognostic index may improve the prediction of survival and selection of therapy. Many prognostic factors have been identified often based on retrospective, underpowered studies with unclear analyses. Data from 653 patients were analysed. Continuous variables are often simplified assuming a linear relationship with log hazard or introducing a step function (dichotomising). Misspecification may lead to inappropriate conclusions but has not been previously investigated in pancreatic cancer studies. Models based on standard assumptions were compared with a novel approach using nonlinear fractional polynomial (FP) transformations. The model based on FP-transformed covariates was most appropriate and confirmed five previously reported prognostic factors: albumin, CA19-9, alkaline phosphatase, LDH and metastases, and identified three additional factors not previously reported: WBC, AST and BUN. The effects of CA19-9, alkaline phosphatase, AST and BUN may go unrecognised due to simplistic assumptions made in statistical modelling. We advocate a multivariable approach that uses information contained within continuous variables appropriately. The functional form of the relationship between continuous covariates and survival should always be assessed. Our model should aid individual patient risk stratification and the design and analysis of future trials in pancreatic cancer

Thermal conductivity and latent heat thermal energy storage properties of LDPE/wax as a shape-stabilized composite phase change material

Phase change material (PCM) composites based on low-density polyethylene (LDPE) with paraffin waxes were investigated in this study. The composites were prepared using a meltmixing method with a Brabender-Plastograph. The LDPE as the supporting matrix kept the molten waxes in compact shape during its phase transition from solid to liquid. Immiscibility of the PCMs (waxes) and the supporting matrix (LDPE) is a necessary property for effective energy storage. Therefore, this type paraffin can be used in a latent heat storage system without encapsulation. The objective of this research is to use PCM composite as integrated components in a passive solar wall. The proposed composite TROMBE wall allows daily storage of the solar energy in a building envelope and restitution in the evening, with a possible control of the air flux in a ventilated air layer. An experimental set-up was built to determine the thermal response of these composites to thermal solicitations. In addition, a DSC analysis was carried out. The results have shown that most important thermal properties of these composites at the solid and liquid states, like the "apparent" thermal conductivity, the heat storage capacity and the latent heat of fusion. Results indicate the performance of the proposed system is affected by the thermal effectiveness of phase change material and significant amount of energy saving can be achieved.Scopu

Simple Sequence Repeat Identification and Endocarp Characterization of Olive Tree Accessions in a Tunisian Germplasm Collection

8 páginas, 2 figuras, 3 tabvas.Most traditional olive-producing countries possess a diversified genetic patrimony in Olea europaea L. Since the emergence of modern olive growing system, the identification, classification, and conservation of autochthonous olive cultivars is a priority for these countries. In this work, a total of 84 accessions belonging to the "Boughrara"-Sfax olive germplasm collection located in Tunisia have been screened using a powerful set of eight simple sequence repeat markers (SSRs). The study revealed a high genetic variability among the collection and detected a total of 64 alleles. For better management of the mentioned germplasm bank, an improved classification of the entries, including new denominations, has been proposed. In addition, several cases of mislabeling, synonymy, and homonymy have been clarified. Genetic relationships among cultivars have been analyzed showing four major clusters. Finally, a correspondence factor analysis demonstrated that cultivars tend to cluster depending on their main use as oil or table olives. No clear clustering tendencies were observed when the geographical origin of cultivars was used as the criteria for the analysis. All results obtained by SSR screening and classification were in accordance with classification based on morphological traits of fruit endocarps.This research has been supported by FEDER cofunded Projects BFU 2004-00601/BFI, BFU2008- 00629, and Junta de Andalucı´a P06-AGR-01791. Research carried out by M. Fendri was funded by AECID.Peer reviewe

Influence des mécanismes de décomposition de la ferrite sur la résistance à la corrosion d’un acier inoxydable austéno ferritique vieilli

L’effet des modes de décomposition de la ferrite vieillie de la nuance d’acier inoxydable austéno-ferritique type X6 CrNiMoCu 25-6 sur la résistance à la corrosion par piqûres et intercristalline dans l’eau de mer synthétique, a été étudié par des essais électrochimiques de types potentiodynamiques cycliques, potentiocinétiques et DL-EPR (Double Loop Electrochemical Potentiokinetic Reactivation). Il a été établi que le mécanisme de décomposition spinodale gouvernant la démixtion de la ferrite (formation de phases α’ et G) au cours d’un vieillissement de 1000 h à 400 °C, engendre des fluctuations de teneur en chrome à très courtes distances (7 à 13 nm) qui n’affectent pas la résistance à la corrosion de l’acier étudié. Par contre, le vieillissement à 500 °C pendant 1000 h conduit à une décomposition de type eutectoïde de la ferrite en carbures (M23C6) et en phases intermétalliques (I, R, χ et η), par le mécanisme de germination et croissance, mettant en jeu des fluctuations de composition chimique plus importantes et à plus grandes distances, responsables d’un important affaiblissement de la résistance à la corrosion localisée de la nuance étudiée dans l’eau de mer synthétique

Fistule vésico-cutanée par plaie pénétrante de la region glutéale par arme blanche associée à une lésion du nerf sciatique. A propos d\'un cas

No Abstract. African Journal of Urology Vol. 11(3) 2005: 244-24