281 research outputs found

    La modernisation de l’agriculture en Amérique latine

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    Epidemiology, Prognosis, and Evolution of Management of Septic Shock in a French Intensive Care Unit: A Five Years Survey

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    Purpose. To evaluate the epidemiology, prognosis, and management of septic shock patients hospitalized in our intensive care unit (ICU). Materiel and Methods. Five-year monocenter observational study including 320 patients. Results. ICU mortality was 54.4%. Independent mortality risk factors were mechanical ventilation (OR = 4.97), Simplify Acute Physiology Score (SAPS) II > 60 (OR = 4.28), chronic alcoholism (OR = 3.38), age >65 years (OR = 2.65), prothrombin ratio <40% (OR = 2.37), and PaO2/FiO2 ratio <150 (OR = 1.91). These six mortality risk factors recovered allow screening immediately septic shock patients with a high mortality risk. Morbidity improved with time (diminution of septic shock complications, increase of the number of days alive free from mechanical ventilation and vasopressors on day 28), concomitant to an evolution of the management (earlier institution of all replacement and medical therapies and more initial volume expansion). There was no difference in mortality. Conclusion. Our study confirms a high mortality rate in septic shock patients despite a new approach of treatment

    Validation of a Prediction Rule for Prognosis of Severe Community-Acquired Pneumonia

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    In a previous study, we developed a prognostic prediction rule, based on nine prognostic variables, capable to estimate and to adjust the mortality rate of patients admitted in intensive care unit for severe community-acquired pneumonia. A prospective multicenter study was undertaken to evaluate the performance of this rule. Five hundred eleven patients, over a 7-year period, were studied. The ICU mortality rate was 29.0%. In the 3 initial risk classes, we observed significantly increasing mortality rates (8.2% in class I, 22.8% in class II and 65.0% in class III) (p<0.001). Within each initial risk class, the adjustment risk score identified subclasses exhibiting significantly different mortality rates: 3.9% and 33.3% in class I; 3.1%, 12.9% and 63.3% in class II; and 55.8% and 82.5% in class III. Compared with mortality rates predicted by our previous study, only a few significant differences were observed. Our results demonstrate the performance and reproductibility of this prognostic prediction rule

    What Factors Shape Spatial Distribution of Biomass in Riparian Forests? Insights from a LiDAR Survey over a Large Area

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    Riparian ecosystems are home to a remarkable biodiversity, but have been degraded in many regions of the world. Vegetation biomass is central to several key functions of riparian systems. It is influenced by multiple factors, such as soil waterlogging, sediment input, flood, and human disturbance. However, knowledge is lacking on how these factors interact to shape spatial distribution of biomass in riparian forests. In this study, LiDAR data were used in an individual tree approach to map the aboveground biomass in riparian forests along 200 km of rivers in the Meuse catchment, in southern Belgium (Western Europe). Two approaches were tested, relying either on a LiDAR Canopy Height Model alone or in conjunction with a LiDAR point cloud. Cross-validated biomass relative mean square errors for 0.3 ha plots were, respectively, 27% and 22% for the two approaches. Spatial distribution of biomass patterns were driven by parcel history (and particularly vegetation age), followed by land use and topographical or geomorphological variables. Overall, anthropogenic factors were dominant over natural factors. However, vegetation patches located in the lower parts of the riparian zone exhibited a lower biomass than those in higher locations at the same age, presumably due to a combination of a more intense disturbance regime and more limiting growing conditions in the lower parts of the riparian zone. Similar approaches to ours could be deployed in other regions in order to better understand how biomass distribution patterns vary according to the climatic, geological or cultural contexts.Les écosystèmes riverains abritent une biodiversité remarquable, mais ils ont été dégradés dans de nombreuses régions du monde. La biomasse végétale est essentielle à plusieurs fonctions clés des systèmes riverains. Elle est influencée par de multiples facteurs, tels que l'engorgement du sol, l'apport de sédiments, les inondations et les perturbations humaines. Cependant, les connaissances concernant la façon dont ces facteurs interagissent pour façonner la distribution spatiale de la biomasse dans les forêts riveraines sont fragmentaires. Dans cette étude, les données LiDAR ont été utilisées dans une approche à l’échelle de l’arbre pour cartographier la biomasse aérienne dans les forêts riveraines le long de 200 km de rivières dans le bassin versant de la Meuse, dans le sud de la Belgique (Europe occidentale). Deux approches ont été testées, s'appuyant sur un modèle numérique de hauteur LiDAR seul ou en conjonction avec un nuage de points LiDAR. Les erreurs quadratiques moyennes relatives de la biomasse pour des parcelles de 0,3 ha étaient respectivement de 27 % et 22 % pour les deux approches. La distribution spatiale des modèles de biomasse était surtout influencée par l'historique des parcelles (et en particulier l'âge de la végétation), suivie par l'utilisation des terres et les variables topographiques ou géomorphologiques. Dans l'ensemble, les facteurs anthropiques étaient dominants par rapport aux facteurs naturels. Cependant, les parcelles de végétation situées dans les parties inférieures de la zone riveraine présentaient une biomasse plus faible que celles situées dans les parties supérieures au même âge, probablement en raison de la combinaison d'un régime de perturbation plus intense et de conditions de croissance plus limitantes dans les parties inférieures de la zone riveraine. Des approches similaires à la nôtre pourraient être déployées dans d'autres régions afin de mieux comprendre comment les schémas de distribution de la biomasse varient en fonction des contextes climatiques, géologiques ou culturels.Peer reviewe

    Chicken or the Egg - Computational Data Attacks or Physical Attacks

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    Side-channel and fault injection analyses are well-known domains that have been used for years to evaluate the resistance of hardware based products. These techniques remain a threat for the secret assets embedded in products like smart cards or System On Chip. But most of these products contain nowadays several strong protections rendering side-channel and fault attacks difficult or inefficient. For two decades embedded cryptography for payment, pay tv, identity areas have relied a lot on secure elements. Nowadays more alternative solutions on mobile phones appear with the aim to offer software-based security services including payment and security solutions as the HCE and DRM products. Cryptographic operations running in such applications are then executed most often on unprotected hardware devices. Therefore the binary code is often accessible to attackers who can use static and dynamic reverse engineering techniques to extract and analyse operations including data modification as faults. Hence, hiding or obfuscating secrets and/or whitebox cryptography becomes a strong alternatives to secure element storage for assets. We explain in this paper how directly from the binary or with the extracted source code we can perform statistical and fault analyses using similar techniques as those used in hardware-based security. This concerns particularly side-channel or fault injections techniques. Using our tool and virtualization technique, an attacker can emulate and trace and modify any chosen computational data (memory or register manipulation, any machine language operation) executed in the mobile application. It means the attacker is not no longer restricted by any physical limitations imposing a leakage model (and additional noise) or making fault injection tied with physical limitations. Hence statistical and fault attacks can go potentially further in software-based implementation compared to hardware based devices. As a consequence, complex techniques like high order, collision and horizontal statistical attacks become very efficient and can be easily performed on the computational data execution traces. A similar consequence applies for fault injection attacks. Hence the word statistical and fault analysis on computational data becomes more appropriate and one can wonder who has been the first between computational data or physical attack techniques? Chicken or the Egg

    ANALYSE DES PROGRAMMES D’ACTIONS PARIS ÉLABORÉS PAR LES GESTIONNAIRES DE COURS D’EAU POUR LA PÉRIODE 2022-2027

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    En application de nouvelles dispositions du Code de l’Eau entrées en vigueur fin 2018, les gestionnaires de cours d’eau publics wallons ont élaboré des programmes d’actions détaillés (PARIS) pour la période 2022-2027, à l’échelle d’unités de gestion physiquement homogènes appelées « secteurs ». Ces PARIS ont pour vocation de contribuer à une gestion intégrée, durable et coordonnée des cours d’eau, ainsi qu’à la prise en compte de leurs quatre fonctions : hydraulique, écologique, économique et socioculturelle. L'objectif de cet article est d'analyser ces PARIS, c'est-à-dire les enjeux identifiés, les objectifs de gestion fixés ainsi que les travaux planifiés par les gestionnaires pour chacun des 6 254 secteurs du réseau hydrographique. Le premier enseignement est le taux d’adhésion élevé des gestionnaires de cours d’eau, d'autant plus remarquable qu’il s’agit d’une nouvelle approche, impliquant l’utilisation d’un nouvel outil informatique. Il ressort également que les enjeux les plus fréquemment encodés sont les enjeux inondation et biodiversité, très souvent combinés l’un avec l’autre au sein des mêmes secteurs. Les enjeux socioculturel et économique viennent loin derrière. L’analyse révèle une distribution équilibrée entre travaux visant à lutter contre les inondation et ceux visant à préserver ou à restaurer la qualité écologique des cours d’eau. La moitié des secteurs se sont vu planifier comme unique mesure « visite et surveillance », car ils ne nécessitent pas de gestion active. Enfin, la variabilité des enjeux, objectifs de gestion et mesures définis sur les secteurs a pu être mise en évidence à l’échelle des différents sous-bassins hydrographiques

    Effects of high doses of selenium, as sodium selenite, in septic shock: a placebo-controlled, randomized, double-blind, phase II study

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    INTRODUCTION: Sepsis is associated with the generation of oxygen free radicals and (lacking) decreased selenium plasma concentrations. High doses of sodium selenite might reduce inflammation by a direct pro-oxidative effect and may increase antioxidant cell capacities by selenium incorporation into selenoenzymes. We investigated the effects of a continuous administration of high doses of selenium in septic shock patients. METHODS: A prospective, multicentre, placebo-controlled, randomized, double-blind study was performed with an intention-to-treat analysis in severe septic shock patients with documented infection. Patients received, for 10 days, selenium as sodium selenite (4,000 μg on the first day, 1,000 μg/day on the nine following days) or matching placebo using continuous intravenous infusion. The primary endpoint was the time to vasopressor therapy withdrawal. The duration of mechanical ventilation, the mortality rates in the intensive care unit, at hospital discharge, and at 7, 14, 28 and 180 days and 1 year after randomization, and adverse events were recorded. RESULTS: Sixty patients were included (placebo, n = 29; selenium, n = 31). The median time to vasopressor therapy withdrawal was 7 days in both groups (95% confidence interval = 5–8 and 6–9 in the placebo and selenium groups, respectively; log-rank, P = 0.713). The median duration of mechanical ventilation was 14 days and 19 days in the placebo and selenium groups, respectively (P = 0.762). Mortality rates did not significantly differ between groups at any time point. Rates of adverse events were similar in the two groups. CONCLUSION: Continuous infusion of selenium as sodium selenite (4,000 μg on the first day, 1,000 μg/day on the nine following days) had no obvious toxicity but did not improve the clinical outcome in septic shock patients. Trial Registration = NCT00207844
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