Regional Arctic sea ice predictability and prediction on seasonal to interannual timescales

The fast depletion of the Arctic sea ice extent observed during the last three decades has awakened concerns about the consequences of such changes at hemispheric scales, and opened socio-economic opportunities such as maritime transport. This PhD project aims at investigating the sources of predictability and prediction skill of Arctic sea ice conditions at the regional scale. The first months have been dedicated to the investigation of the mechanisms behind the development of model systematic errors in seasonal regional predictions

Personalized dietary advices provided by a dietitian increase calcium intake in outpatients with multiple sclerosis—Results from a randomized, controlled, single-blind trial

Background and aimsMultiple sclerosis (MS) is associated with osteoporosis, possibly due to neurological disability and decreased calcium intake. The objective of this study was to evaluate the efficacy of a personalized nutritional advice program by a dietitian compared to the delivery of a standard advice form to optimize dietary calcium intake in outpatients with MS.MethodsWe performed a randomized, controlled, parallel trial comparing the efficacy of a personalized dietary advice (PDA) program to standard advice form (SAF) to increase daily calcium intake in MS patients. The study population was composed by patients with relapsing-remitting MS aged 18–69 years old. PDA program consisted in dietary advice delivered by a dietitian at baseline, 1 month, and 3 months. Calcium and nutrient intake in patients from both groups was evaluated at baseline and 6 months using a dietary survey.ResultsOf the 194 patients screened for inclusion, 182 patients were included (79% female, median age of 42 years, and median EDSS of 2.0), and randomized to SAF (n = 92) or PDA (n = 90). At 6 months, median calcium intake increased by 241 mg/day in the PDA group and decreased by 120 mg/day in the SAF group (p < 0.0001). However, the median calcium intake was 947 mg/day in the SAF group and 778 mg/day in the PDA group at baseline (p = 0.0077), potentially favoring the effect of dietary advice. Complementary analyses focusing on patients with insufficient calcium intakes at baseline revealed comparable values in both groups (p = 0.69). Of those, patients included in the PDA group obtained significantly higher calcium intakes at 6 months than patients from the SAF group (p = 0.0086) independently of EDSS, PASAT, HADS and EQ-5D scores.ConclusionThis work shows the efficacy of dietary management based on personalized advice program over 3 months to durably increase calcium consumption in MS patients with insufficient calcium intake.Clinical trial registrationclinicaltrials.gov, identifier NCT02664623

CARACTERISATIONS THERMODYNAMIQUE ET STRUCTURALE DE MELANGES MULTIPARAFFINIQUES SYNTHETIQUES ET REELS. ETUDE DE LEUR CRISTALLISATION DANS LE TETRADECANE

NANCY/VANDOEUVRE-INPL (545472102) / SudocSudocFranceF

Évaluation du suivi d'une fiche d'aide à la prescription de la warfarine chez le patient âgé hospitalisé

Afin d'améliorer la sécurité d'emploi des antivitamines-K chez le patient âgé à l'hôpital Charles Foix (AP-HP, Ivry-sur Seine), ont été, élaborées, en 1999, des recommandations de prescription et de surveillance biologique lors de l'initiation d'un traitement par la warfarine chez les sujets > 70 ans, dont l'INR cible est entre 2 et 3. Dix-huit mois après leur diffusion sous la forme d'une fiche au format poche, nous avons réalisé une étude prospective afin dévaluer l'adhésion des prescripteurs à la fiche et l'intérêt pour le patient du respect de ces recommandations. Ont été inclus 89 patients, d'âge moyen 87 ans, ayant débuté un traitement par warfarine entre mai 2001 et avril 2002. Les causes de non-suivi ont été recherchées. Nous avons réalisé ensuite une enquête de satisfaction auprès des prescripteurs. L'analyse des causes de non-suivi et des réponses à l'enquête de satisfaction nous a permis de conclure à une adhésion de principe à la fiche pour plus de 70 % des prescripteurs.CHATENAY M.-PARIS 11-BU Pharma. (920192101) / SudocSudocFranceF

Exfoliated nanoplatelets of an Aurivillius phase, Bi3.25La0.75Ti3O12: Characterisation by X-ray diffraction and by high-resolution electron microscopy

International audienc

Regional Arctic sea ice predictability and prediction on seasonal to interannual timescales

The fast depletion of the Arctic sea ice extent observed during the last three decades has awakened concerns about the consequences of such changes at hemispheric scales, and opened socio-economic opportunities such as maritime transport. This PhD project aims at investigating the sources of predictability and prediction skill of Arctic sea ice conditions at the regional scale. The first months have been dedicated to the investigation of the mechanisms behind the development of model systematic errors in seasonal regional predictions

Auto-assemblage de nanocristaux d'oxalate de cuivre

La nanostructuration de la matière par auto-assemblage est actuellement un des domaines de recherche fondamentale les plus dynamiques et ouvre de vastes perspectives technologiques. Cette thèse se propose d étudier l'auto-assemblage de nanocristaux d'oxalate de cuivre. Ce composé peut être considéré comme système modèle dont les propriétés permettent une transposition à l'élaboration de nanostructures complexes. Une étude bibliographique portant d'une part sur le phénomène d'auto-assemblage à l'échelle mésoscopique, d'autre part sur le cas particulier des oxalates de métaux divalents constitue la première partie de ce travail. Puis, la caractérisation structurale des nanocristaux d'oxalate de cuivre et l'influence des conditions de synthèse sur leur auto-assemblage permettent d'aboutir à un modèle de mésocristaux issus d'une orientation des nanocristaux par reconnaissance de faces cristallines. Enfin, les modifications morphologiques des mésocristaux en présence d'additifs et l'étude spectroscopique de ces nanostructures confirment le modèle proposé par la mise en évidence d'une adsorption sélective des additifs sur certaines faces des nanocristaux.The nanostrucuration of matter by self-assembly is nowadays one of the most dynamic areas in fundamental research and opens many technological perspectives. In this PhD thesis is studied the self-assembly of copper oxalate nanocrystals. This compound can be considered as a model system whose properties can be transposed to the elaboration of complex nanostructures. A bibliographical study, covering on one hand the self-assembly phenomenon at the mesoscopic scale, and on the other hand the particular case of divalent metal oxalates constitutes the first part of this work. Then, the structural characterization of copper oxalate nanocrystals and the influence of the synthesis conditions on their self-assembly lead to a model of mesocrystals built from an orientation of nanocrystals by crystal faces recognition. Finally, the morphological modifications of mesocrystals in presence of additives and the spectroscopic study of these nanostructures confirm the prpoposed model by highlighting a selective adsorption of additives on some of the nanocrystals faces.TOULON-BU Centrale (830622101) / SudocSudocFranceF

Shape dependence of photosensitive properties of WO3 oxide for photocatalysis under solar light irradiation

International audienceTwo morphologies of nanostructured WO3, nanoplatelets (NP) and pseudospheres (PS), were synthesized using a simple chemical route. The obtained powders were structurally characterized using thermal analyses and a combined XRD with Rietveld refinement. Their morphological and growth mechanisms were followed by SEM during the maturation phase. The results showed a square/rectangular shape and pseudospherical morphology, which exhibited a monoclinic phase after calcination at 400 degrees C and an orthorhombic phase after calcination at 500 degrees C. The temperature treatment induced an increase of grain size for the NP lateral size, while the PS size remains temperature independent. The photocatalytic activity was evaluated by the degradation of methylene blue under solar light irradiation. The degradation process was investigated by studying the photosensitive properties, optical absorption, photoluminescence and photoresistance. The photodegradation activity of methylene blue is composed of a rapid and strong adsorption step followed by a photoinduced catalytic process. The PS sample revealed a higher adsorption rate than NP powders at the low calcination temperature, while the photoinduced catalysis is better at the high calcination temperature, reaching 88% at 500 degrees C. The photosensitive properties showed a low luminescence intensity and a long charge carrier recombination time, thus indicating the photocatalytic efficiency of the elaborated samples

An assessment of regional sea ice predictability in the Arctic ocean

Arctic sea ice plays a central role in the Earth’s climate. Changes in the sea ice on seasonal-to-interannual timescales impact ecosystems, populations and a growing number of stakeholders. A prerequisite for achieving better sea ice predictions is a better understanding of the underlying mechanisms of sea ice predictability. Previous studies have shown that sea ice predictability depends on the predictand (area, extent, volume), region, and the initial and target dates. Here we investigate seasonal-to-interannual sea ice predictability in so-called “perfect-model” 3-year-long experiments run with six global climate models initialized in early July. Consistent with previous studies, robust mechanisms for reemergence are highlighted, i.e. increases in the autocorrelation of sea ice properties after an initial loss. Similar winter sea ice extent reemergence is found for HadGEM1.2, GFDL-CM3 and E6F, while a long sea ice volume persistence is confirmed for all models. The comparable predictability characteristics shown by some of the peripheral regions of the Atlantic side illustrate that robust similarities can be found even if models have distinct sea ice states. The analysis of the regional sea ice predictability in EC-Earth2.3 demonstrates that Arctic basins can be classified according to three distinct regimes. The central Arctic drives most of the pan-Arctic sea ice volume persistence. In peripheral seas, we find predictability for the sea ice area in winter but low predictability throughout the rest of the year, due to the particularly unpredictable sea ice edge location. The Labrador Sea stands out among the considered regions, with sea ice predictability extending up to 1.5 years if the oceanic conditions upstream are known