Incidence and Risk Factors of First-Line HAART Discontinuation: Is it Worth Choosing Competing Risk or Standard Survival Approaches?

International audienceObjectives: To estimate the incidences of first-line HAART discontinuation (for intolerance, treatment failure or treatment simplification) and their risk factors by standard survival (1-KM, Cox model) or competing risk approach (CIF, Fine-Gray model) in HIV infected patients. Methods: We studied 1136 patients receiving first-line Highly Active Antiretroviral Therapies (HAART), aged over 18 years, from the Dat'AIDS cohort, Toulouse, France, between January 2000 and June 2008. Cumulative incidence was estimated with 1-KM and CIF estimators and risk factors with Cox and Fine-Gray models. Results: There were 265 discontinuations for intolerance, 136 simplifications, 101 treatment failure and 274 other reasons. One year incidences were 19.0% versus 16.8%, 8.0% versus 6.0%, 6.3% versus 4.8% and 20.0% versus 17.3%, with the estimators 1-KM and CIF, respectively. For intolerance, both models identified similar risk factors. For risk factors of simplification or treatment failure, results differed by the model. Conclusions: As expected, the 1-KM overestimates the incidence of treatment discontinuation. For early and frequent events such as intolerance, the Cox and the Fine-Gray models appear to give similar results. For late and rare events, potentially exposed to competing risk, results differed. The common or specific nature of a factor may also play a role

Natural polymorphism in the thrombospondin-related adhesive protein of Plasmodium falciparum

We have developed a typing system using natural sequence variation in the thrombospondin-related adhesive protein (TRAP) gene of Plasmodium falciparum. This method permits a haplotype to be assigned to any particular TRAP gene. We have applied this method to a hospital-based, case control-study in Mali. Previous sequence variation and conservation in TRAP has been confirmed. Particular TRAP haplotypes can be used as geographic hallmarks. Because of the high level of conflict between characters, we have examined the phylogenetic relationships between parasites using a network approach. Having received patient samples from urban and periurban areas of Bamako, the majority of haplotypes were closely related and distinct from TRAP sequences present in other continents. This suggests that the structure of TRAP can only tolerate a limited number of sequence variations to preserve its function but that this is sufficient to allow the parasite to evade the host's immune system until a long-lived immune response can be maintained. It may also reflect host genetics in that certain variants may escape the host immune response more efficiently than others. For vaccine design, sequences from the major regional variants may need to be considered in the production of effective subunit vaccines

Improved Temperature Sounding and Quality Control Methodology Using AIRS/AMSU Data: The AIRS Science Team Version 5 Retrieval Algorithm

This paper describes the AIRS Science Team Version 5 retrieval algorithm in terms of its three most significant improvements over the methodology used in the AIRS Science Team Version 4 retrieval algorithm. Improved physics in Version 5 allows for use of AIRS clear column radiances in the entire 4.3 micron CO2 absorption band in the retrieval of temperature profiles T(p) during both day and night. Tropospheric sounding 15 micron CO2 observations are now used primarily in the generation of clear column radiances .R(sub i) for all channels. This new approach allows for the generation of more accurate values of .R(sub i) and T(p) under most cloud conditions. Secondly, Version 5 contains a new methodology to provide accurate case-by-case error estimates for retrieved geophysical parameters and for channel-by-channel clear column radiances. Thresholds of these error estimates are used in a new approach for Quality Control. Finally, Version 5 also contains for the first time an approach to provide AIRS soundings in partially cloudy conditions that does not require use of any microwave data. This new AIRS Only sounding methodology, referred to as AIRS Version 5 AO, was developed as a backup to AIRS Version 5 should the AMSU-A instrument fail. Results are shown comparing the relative performance of the AIRS Version 4, Version 5, and Version 5 AO for the single day, January 25, 2003. The Goddard DISC is now generating and distributing products derived using the AIRS Science Team Version 5 retrieval algorithm. This paper also described the Quality Control flags contained in the DISC AIRS/AMSU retrieval products and their intended use for scientific research purposes

Mieux gérer l'information sur les périmètres irrigués collectifs : un outil au service de leur efficacité

International audienceAu Mali, l'Office du Niger gère un périmètre d'irrigation entièrement gravitaire de 70 000 ha. La programmation et le suivi de la maintenance de ce réseau sont assurés paritairement par l'Office du Niger et des représentants des usagers. Ces activités rencontrent de grandes difficultés pour mobiliser l'information nécessaire. En partant des pratiques actuelles des différents acteurs et en explicitant, avec eux, les procédures de gestion employées, une application informatique a été mise au point (le système d'information pour la maintenance à l'Office du Niger) afin de gérer les données de manière uniformisée, d'en assurer le traitement informatique et de les stocker. Son implantation dans les divers services de l'Office du Niger (service de gestion de l'eau, service des aménagements hydrauliques, bureau des procédures de marchés) a fait l'objet de formations et d'actions d'accompagnement. Ce système assure les fonctionnalités de programmation et de suivi des interventions de maintenance ainsi que la gestion de l'ensemble des données de références que sont les composants du réseau d'irrigation - canaux, cavaliers et pistes, ouvrages - et les nomenclatures. La lenteur du processus d'intégration de ce nouveau système est due d'une part à la charge de travail importante pour mettre en place les données de référence, et d'autre part à la volonté de laisser les agents des services de l'Office s'approprier cet outil à leur rythme. Cependant, le manque de supports et d'assistance informatique fonctionnelle, rapprochée et permanente a pénalisé ce processus, de même l'engagement de la hiérarchie est indispensable pour intégrer pleinement ce logiciel dans la gestion. Si, aujourd'hui, l'emploi du logiciel n'est pas encore systématisé pour la gestion de la maintenance, les réflexions collectives qui ont généré son élaboration ont permis de confronter et d'uniformiser le vocabulaire et les pratiques de gestion de la maintenance des différents services de l'Office du Niger. Des supports d'information, principalement cartographiques, destinés aux paysans et à leurs représentants au sein des comités paritaires, seront prochainement soumis à la critique de ces usagers. Ce type de démarche et de concepts devrait trouver des applications sur d'autres périmètres du même type

Trends in Real Food Prices in Six Sub-Saharan African Countries

Demand and Price Analysis, Downloads July 2008-July 2009: 12,

Species occurrence of cetaceans in Guinea, including humpback whales with southern hemisphere seasonality

An initial inventory of the dolphins and whales occurring in Guinea's coastal waters is documented primarily from specimens and photographic evidence obtained from strandings and by-catches. Seven species are fully validated, four odontocetes, Tursiops truncatus, Sousa teuszii, Stenella frontalis, Kogia breviceps and three balaenopterid whales: Balaenoptera brydei, Balaenoptera acutorostrata and Megaptera novaeangliae. Another three reported species (Globicephala macrorhynchus, Steno bredanensis and Delphinus delphis) are insufficiently supported but thought to be valid. Small cetaceans landed as by-catch and a stranded whale were used for human consumption, but no evidence of substantial takes, directed or by-catch, was found. However, concern is raised about even minimal takes of the vulnerable Atlantic humpback dolphin. The seasonal presence of three confirmed humpback whales, two strandings (July and September) and a sighting (October), is synchronous with the species' southern hemisphere wintering/breeding season in low latitudes. We hypothesize that these whales may comprise the north-westernmost range of the population that breeds/overwinters in coastal waters of the Bight of Benin, northern Gulf of Guinea

The mechanisms of plaster drying

International audienceWe show that the drying rate of plaster pastes is significantly lower than that expected for a pure liquid evaporating from a simple homogeneous porous medium. This effect is enhanced by the air flow velocity and the initial solid/water ratio. Further tests under various conditions and with the help of additional techniques (MRI, ESEM, Microtomography) for measuring the drying rate and local characteristics (water content, porosity) prove that this effect is due to the crystallization of gypsum ions below the sample free surface, which creates a dry region and decreases the drying rate by increasing the length of the path the vapor has to follow before reaching the free surface