Évaluation des ressources en eau de la Martinique : calcul spatialisé de la pluie efficace et validation à l’échelle du bassin versant

L’évaluation des différents termes du bilan hydrologique à l’échelle d’un bassin versant constitue l’un des points clés de la gestion des ressources en eau, et ce, tout particulièrement dans les régions montagneuses présentant de fortes variations spatiales de la pluviométrie et de l’évapotranspiration. Une méthodologie, basée sur le modèle classique de Thornthwaite, est proposée. Elle prend en compte les différents types de sols, l’occupation des sols ainsi que les effets topographiques et calcule les différents termes du bilan hydrologique (pluie, évapotranspiration, pluie efficace, etc.). L’approche a été mise en oeuvre à l’échelle du kilomètre carré, pour l’ensemble de l’île de la Martinique (1 080 km2), puis validée à l’échelle du bassin versant, en comparant les pluies efficaces calculées avec les débits mesurés aux stations de jaugeage. Malgré l’absence de calage des différents paramètres du modèle, les résultats sont très satisfaisants. Une surestimation de la pluie efficace est néanmoins observée pour la plupart des bassins versants utilisés pour la validation du modèle. Cet écart est attribué à une sous-estimation de l’évapotranspiration potentielle, la plupart des bassins versants comportant une composante forestière significative, non prise en compte dans le modèle.The assessment of the various components of the hydrologic budget at catchment scale represents a key challenge for water resources management. This is especially true for regions characterized by important spatial variability in rainfall or evapotranspiration due, for example, to topographical effects. A methodology, based on the classical Thornthwaite model, is proposed to account for soil types, land cover changes and topographical effects on the main components of the water cycle (rainfall, evapotranspiration and efficient rainfall). The approach is developed for the whole Martinique Island (French West Indies, 1080 km2) using a 1-km2 resolution and validated at catchment scale comparing computed efficient rainfall with measured discharge at several gauging stations. Despite the absence of any calibration of the model parameters, the results are satisfying. A slight overestimation of the efficient rainfall is generally observed for the validation watersheds. This discrepancy is interpreted as an underestimation of potential evapotranspiration as the classical Penman-Montheit formula for grass is used despite the presence of forested areas in most of the watersheds

A rewiring model of intratumoral interaction networks.

Intratumoral heterogeneity (ITH) has been regarded as a key cause of the failure and resistance of cancer therapy, but how it behaves and functions remains unclear. Advances in single-cell analysis have facilitated the collection of a massive amount of data about genetic and molecular states of individual cancer cells, providing a fuel to dissect the mechanistic organization of ITH at the molecular, metabolic and positional level. Taking advantage of these data, we propose a computational model to rewire up a topological network of cell-cell interdependences and interactions that operate within a tumor mass. The model is grounded on the premise of game theory that each interactive cell (player) strives to maximize its fitness by pursuing a rational self-interest strategy, war or peace, in a way that senses and alters other cells to respond properly. By integrating this idea with genome-wide association studies for intratumoral cells, the model is equipped with a capacity to visualize, annotate and quantify how somatic mutations mediate ITH and the network of intratumoral interactions. Taken together, the model provides a topological flow by which cancer cells within a tumor cooperate or compete with each other to downstream pathogenesis. This topological flow can be potentially used as a blueprint for genetically intervening the pattern and strength of cell-cell interactions towards cancer control

Eradication of an outbreak of vancomycin-resistant Enterococcus (VRE): the cost of a failure in the systematic screening

BACKGROUND: Vancomycin-resistant enterococci (VRE) are still a concern in hospital units tending to seriously ill patients. However, the cost-effectiveness of active surveillance program to identify asymptomatically VRE colonized patient remains debatable. This work aims at evaluating the cost of a failure in the active surveillance of VRE that had resulted in an outbreak in a French University Hospital. FINDINGS: A VRE outbreak was triggered by a failure in the systematic VRE screening in a medico-surgical ward specialised in liver transplantation as a patient was not tested for VRE. This failure was likely caused by the reduction of healthcare resource. The outbreak involved 13 patients. Colonized patients were grouped in a dedicated part of the infectious diseases unit and tended by a dedicated staff. Transmission was halted within two months after discovery of the index case. The direct cost of the outbreak was assessed as the cost of staffing, disposable materials, hygiene procedures, and surveillance cultures. The loss of income from spare isolation beds was computed by difference with the same period in the preceding year. Payments were drawn from the hospital database. The direct cost of the outbreak (2008 Euros) was €60 524 and the loss of income reached €110 915. CONCLUSIONS: Despite this failure, the rapid eradication of the VRE outbreak was a consequence of the rapid isolation of colonized patient. Yet, eradicating even a limited outbreak requires substantial efforts and resources. This underlines that special attention has to be paid to strictly adhere to active surveillance program

Effect of volcanic dykes on coastal groundwater flow and saltwater intrusion : a field-scale multiphysics approach and parameter evaluation

Acknowledgments This research was primarily based on research grant‐aided by the Irish Department of Communications, Energy and Natural Resources under the National Geoscience Programme 2007–2013. It also benefited from complementary funding from the Scottish Alliance for Geoscience, Environment and Society (SAGES). We acknowledge the contribution in data acquisition of the MSc students in Environmental Engineering at Queen's University Belfast, the landowner for access to the inland fields and the Department of Geography, Archaeology and Paleoecology at QUB for provision of the tidal model of Belfast Lough. The data used are listed in the references, tables, and figures and are available from the corresponding author upon demand. We acknowledge the constructive comments by the Associate Editor and three reviewers, which helped in improving the final manuscript.Peer reviewedPublisher PD

Is clinical practice concordant with the changes in guidelines for antiretroviral therapy initiation during primary and chronic HIV-1 infection? The ANRS PRIMO and COPANA cohorts.

International audienceOBJECTIVE: Guidelines for initiating HIV treatment are regularly revised. We explored how physicians in France have applied these evolving guidelines for ART initiation over the last decade in two different situations: chronic (CHI) and primary HIV-1 infection (PHI), since specific recommendations for PHI are also provided in France. METHODS: Data came from the ANRS PRIMO (1267 patients enrolled during PHI in 1996-2010) and COPANA (800 subjects enrolled at HIV diagnosis in 2004-2008) cohorts. We defined as guidelines-inconsistent during PHI and CHI, patients meeting criteria for ART initiation and not treated in the following month and during the next 6 months, respectively. RESULTS: ART initiation during PHI dramatically decreased from 91% of patients in 1996-99 to 22% in 2007 and increased to 60% in 2010, following changes in recommendations. In 2007, however, after the CD4 count threshold was raised to 350 cells/mm(3) in 2006, only 55% of the patients with CD4≤350 were treated and 66% in 2008. During CHI, ART was more frequently initiated in patients who met the criteria at entry (96%) than during follow-up: 83% when recommendation to treat was 200 and 73% when it was 350 cells/mm(3). Independent risk factors for not being treated during CHI despite meeting the criteria were lower viral load, lower educational level, and poorer living conditions. CONCLUSION: HIV ART initiation guidelines are largely followed by practitioners in France. What can still be improved, however, is time to treat when CD4 cell counts reach the threshold to treat. Risk factors for lack of timely treatment highlight the need to understand better how patients' living conditions and physicians' perceptions influence the decision to initiate treatment

Exploring a new ultrasound score as a clinical predictive tool in patients with rheumatoid arthritis starting abatacept: results from the APPRAISE study

Objectives To explore whether changes in a composite (power Doppler/greyscale ultrasound (PDUS)) synovitis score, developed by the OMERACT-EULAR-Ultrasound Task Force, predict disease activity outcomes in rheumatoid arthritis (RA). Methods Patients with RA who were methotrexate inadequate responders starting abatacept were evaluated. Individual joint PDUS scores were combined in the Global OMERACT-EULAR Synovitis Score (GLOESS) for metacarpophalangeal joints (MCPs) 2–5, all joints (22 paired) and a reduced (9 paired) joint set. The predictive value of changes in GLOESS at week 1–16 evaluations for clinical status and response (Disease Activity Score (DAS)28 (C reactive protein, CRP) <2.6; DAS28(CRP) ≤3.2; DAS28(CRP) ≥1.2 improvement) up to week 24, and correlations between DAS28 and GLOESS were assessed. Results Eighty-nine patients completed the 24-week treatment period. Changes in GLOESS (MCPs 2–5) from weeks 1 to 16 were unable to predict DAS28 outcomes up to week 24. However, significant improvements in GLOESS (MCPs 2–5) were observed at week 12 in patients with DAS28 ≥1.2 improvement at week 24 versus those who did not achieve that clinical response. In patients achieving DAS28 ≥1.2 improvement or DAS28 ≤3.2 at week 24, changes in GLOESS (22 and 9 paired joint sets) were greater in patients who already achieved DAS28 ≥1.2 at week 12 than in those who did not. No significant correlations were found between changes in DAS28 and GLOESS definitions at any time point. Conclusions PDUS was not correlated with clinical status or response as measured by DAS28-derived criteria, and PDUS changes were not predictive of clinical outcome. The discrepancies require further exploration. Trial registration number NCT00767325; Results

Interdisciplinarity and infectious diseases : an Ebola case study

International audienceHigh-profile epidemics such as Ebola, avian influenza, and severe acute respiratory syndrome (SARS) repeatedly thrust infectious diseases into the limelight. Because the emergence of dis-eases involves so many factors, the need for interdisciplinary approaches to studying emerging infections, particularly those originating from animals (i.e., zoonoses), is frequently discussed. However, effective integration across disciplines is challenging in practice. Ecological ideas, for example, are rarely considered in biomedical research, while insights from biomedicine are often neglected in ecological studies of infectious diseases. One practical reason for this is that researchers in these fields focus on vastly different scales of biological organization, which are difficult to bridge both intellectually and methodologically. Nevertheless, integration across biological scales is increasingly needed for solving the complex problems zoonotic diseases pose to human and animal well-being. Motivated by current events, we use Ebola virusas a case study to highlight fundamental questions about zoonoses that can be addressed by integrating insights and approaches across scales

Hydrogeological conceptual model of andesitic watersheds revealed by high-resolution heliborne geophysics

We conducted a multidisciplinary study at the watershed scale of an andesitic-type volcanic island in order to better characterize the hydrogeological functioning of aquifers and to better evaluate groundwater resources. A heliborne Time Domain ElectroMagnetic (TDEM) survey was conducted over Martinique in order to investigate underground volcanic structures and lithology, characterized by high lateral and vertical geological variability and resulting in a very high heterogeneity of their hydrogeological characteristics. Correlations were made on three adjacent watersheds between resistivity data along flight lines and geological and hydrogeological data from 51 boreholes and 24 springs, showing that the younger the formations, the higher their resistivity. Correlation between resistivity, geology and transmissivity data of three aquifers is attested: within the interval 10–100&thinsp;ohm&thinsp;m and within a range of 1 to 5.5&thinsp;Ma, the older the formation, the lower its resistivity, and the older the formation, the higher its transmissivity. Moreover, we demonstrate that the main geological structures lead to preferential flow circulations and that hydrogeological watersheds can differ from topographical watersheds. The consequence is that, even if the topographical watershed is small, underground flows from an adjacent watershed can add significant amounts of water to such a catchment. This effect is amplified when lava domes and their roots are situated upstream, as they present very high hydraulic conductivity leading to deep preferential groundwater flow circulations. We also reveal, unlike basaltic-type volcanic islands, that hydraulic conductivity increases with age in this andesitic-type volcanic island. This trend is interpreted as the consequence of tectonic fracturing associated with earthquakes in this subduction zone, related to andesitic volcanic islands. Finally, our approach allows characterization in detail of the hydrogeological functioning and identification of the properties of the main aquifer and aquitard units, leading to the proposition of a hydrogeological conceptual model at the watershed scale. This working scale seems particularly suitable due to the complexity of edifices, with heterogeneous geological formations presenting high lateral and vertical variability. Moreover, our study offers new guidelines for accurate correlations between resistivity, geology and hydraulic conductivity for volcanic islands. Finally, our results will also help stakeholders toward a better management of water resources.</p

Développement d'un implant à géométrie variable pour le traitement des fractures du fémur proximal chez les personnes âgées

Les fractures du fémur proximal de la personne âgée sont généralement fixées par des dispositifs d ostéosynthèse. Pour les fractures particulières dites inter-trochantériennes, il est possible de fixer la fracture de manière intra-médullaire (à l intérieur de l os) ou de manière extra-médullaire (en dehors de l os). Pour chaque type de traitement, les hôpitaux sont équipés des deux systèmes de fixation. Les différences de morphologie des individus impliquent l existence de multiples références d implants et donc de surcoûts en termes d équipement. Dans ce travail de thèse, un implant original adaptable à la plupart des morphologies a été développé. Cet implant permettra non seulement d offrir aux chirurgiens une souplesse au cours des interventions chirurgicales mais aussi de réduire de manière significative les stocks d implants dans les hôpitaux. Le comportement mécanique de l implant est étudié dans différents cas de fractures par deux approches complémentaires, une méthode numérique par Éléments Finis et une approche expérimentale mettant en oeuvre des techniques de stéréo-corrélation à partir d images de caméras rapides. Les résultats des calculs numériques sont confrontés à ceux issus d essais réalisés sur des fémurs synthétiques, puis cadavériques en laboratoire d anatomie. Les comparaisons avec des implants existants montrent que ce nouveau concept d implant permet une fixation plus stable des fragments osseux et une bonne compression du foyer de fracture.Proximal femoral fractures in the elderly are generally fixed with osteosynthetic devices. For specific fractures called intertrochanteric, it is possible to fix the fracture in an intramedullary way (inside the bone) or in an extramedullary way (outside the bone). For each type of treatment, hospitals are equipped with the two fixing systems. The differences in physical characteristics between individuals imply the existence of multiple references implants and therefore additional costs in terms of equipment. In this thesis work,an original implant adaptable to most people has been developed. This implant will provide surgeons greater flexibility during surgery but also significantly reduce stocks implants in hospitals. The mechanical behavior of the implant is studied in different cases of fractures by two complementary approaches,a finite element analysis and an experimental study employing stereo-image correlation technique from images of high speed cameras. The results of the numerical calculation are compared with those derived from tests on synthetic femurs, then cadaver in anatomy laboratory. Comparisons with existing implants show that this new implant concept allows for a more stable fixation of bone fragments and a good compression of the fracture.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF