Émissions de carbone dans un modèle de production-stocks multi-echelon avec prise en compte des contraintes de délai

Colloque avec actes et comité de lecture. internationale.International audienceNous développons un modèle mathématique d'optimisation qui intègre les émissions de carbone dans un modèle gestion production-stock multi-échelon sous des contraintes de délai. Le modèle proposé capte l’impact de certaines décisions logistiques sur les émissions carbone. Nous nous intéressons principalement aux décisions suivantes : production des produits finis et intermédiaire, approvisionnement chez des fournisseurs internes et externes, positionnement des stocks des différents produits (fini et intermédiaires) aux différents niveaux de la chaîne logistique. Nous considérons deux types de réglementation environnementale: (1) taxe sur les émissions et (2) seuil infranchissable d'émissions carbone. Nous utilisons le modèle pour réaliser un ensemble d’expérimentations et fournir une série d’implications managériales

Kohonen-Based Credal Fusion of Optical and Radar Images for Land Cover Classification

International audienceThis paper presents a Credal algorithm to perform land cover classification from a pair of optical and radar remote sensing images. SAR (Synthetic Aperture Radar) /optical multispectral information fusion is investigated in this study for making the joint classification. The approach consists of two main steps: 1) relevant features extraction applied to each sensor in order to model the sources of information and 2) a Kohonen map-based estimation of Basic Belief Assignments (BBA) dedicated to heterogeneous data. This framework deals with co-registered images and is able to handle complete optical data as well as optical data affected by missing value due to the presence of clouds and shadows during observation. A pair of SPOT-5 and RADARSAT-2 real images is used in the evaluation, and the proposed experiment in a farming area shows very promising results in terms of classification accuracy and missing optical data reconstruction when some data are hidden by clouds

Les centralités du grand Tunis : acteurs, représentations et pratiques urbaines

Cette recherche tente de comprendre l'évolution des discours tenus par les acteurs urbains sur la centralité du Grand Tunis. Ainsi, ce travail de recherche ne s'intéresse pas seulement à l'analyse des discours évoquant les mutations du centre originel de Tunis, puisqu'il cherche également à comprendre les perceptions et les représentations exprimées par les acteurs urbains lorqu'ils abordent la question de l'émergence des centres secondaires dans le périmètre du Grand Tunis. Cette thèse s'intéresse donc en priorité au discours et donc aux représentations sachant que le centre est d'abord " dans nos têtes une figure éminente de la représentation " L'espace urbain, d'une manière générale, et le lieu de centralité en particulier, étant un construit social, il devait être envisagé dans son imbrication avec les deux autres dimensions mentale et matérielle qui le composent. Partant, de ce constat, toute action sur les lieux de centralité étant motivée par les valeurs des différents acteurs urbains (publics, privés ou ordinaires), attribue un sens nouveau à ces lieux. Ainsi, les enjeux urbains des lieux de centralité perçus, conçus ou vécus englobent aussi des enjeux de représentations. Les lieux de centralité pensés et projetés par les aménageurs s'alimentent des représentations mentales et des idéologies de ces derniers. Et ces représentations modèlent à leur tour les représentations spatiales de ces lieux de centralité, tout en influençant, au même temps, les pratiques et par conséquence les rapports des usagers établis avec ces espaces centraux. L'espace de centralité en tant qu'espace réel produit donc des représentations mentales qui guident l'action des différents acteurs urbains sur cet espace en lui donnant du sens et en lui associant des représentations et des images urbaines. En conséquence, c'est par l'étude de l'évolution des représentations de la centralité du Grand Tunis dans les discours des acteurs urbains publics et privés, ainsi qu'à travers les pratiques de ses usagers, que nous allons tenter de comprendre le sens de l'action sur les lieux de centralité de la ville de Tunis ainsi que le sens du discours et des pratiques urbaines qui accompagnent cette action.No resum

Government strategies to secure the supply of medical products in pandemic times

We investigate how to secure reliable access to personal protective equipment (PPE) in pandemics, which are characterized by random occurrences and durations, at the lowest expected cost. The policymaker\u27s strategy is based on a mix of (1) holding ready-to-use strategic stockpile that is acquired at regular price but incurs a holding cost, (2) building partnership with PPE manufacturers to relocate offshore production locally, which guarantees some local supply but requires offering subsidies, and (3) buying PPE from the spot market, which is characterized by long supply lead times and high prices. We model the problem as a Stackelberg game between a policymaker (leader) and a manufacturer (follower). The policymaker decides the PPE stockpile, the subsidy offered to the local manufacturer, and the quantity to buy from the spot market. The manufacturer determines whether to move production onshore. We determine the optimal strategy for each player and study the effect of spot market conditions and pandemic characteristics. Analytical results show that attracting local manufacturers is less costly for the government when the variability of pandemic duration increases. While it is sub-optimal to rely only on the strategic stockpile, holding some stockpile may be necessary even when the PPE can be obtained from the spot market as soon as the pandemic starts. Results reveal policymaker\u27s preference for subsidizing onshore production in the following cases: products with low spot prices (counter-intuitively), spot market with long supply lead time, less frequent pandemics, and shorter pandemics

Chronic crude garlic-feeding modified adult male rat testicular markers: mechanisms of action

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

158 Prothetic abcess complicating Infective endocarditis

The cardiac abscess formation is appraised to 20–30% during the infectious endocarditis (IE). It is more frequent during prosthesis endocarditis and it can reach 60%. The prognosis is generally reserved. Objective To determine echocardiographic, bacteriological and evolutive features of prothetic IE complicated of abscess.Retrospective study including 51 patients having certain or probable IE according to Duke criterias between 2002 and 2005. At 9 patients (17,64%) the endocarditis was complicated of prothetic abscess. It was about 6 men and 3 women with a middle age of 39 ± years. IE was la ate IE in 5 cases. Clinical and biological infectious syndrome was constant. Isolated germs were staphylococcus aureus in 2 cases, GRAM négatif Bacillus in 2 cases. Culture negative endocarditis were noted in 5 cases. Brucellosis serology was positive at one patient. Prothetic abcess was diagnosed by transthoracic echocardiography (TTE) at 2 patients and by transesophagal echocardiography (TEE) at all patients.The abcess was localized on the aortic prosthesis at 5 patients, mitral prothesis at 3 patients and mitroaortic prothesis at one patient. TEE identified annular abcess at 2 patients and a myocardial abcess at 1 patient. Secondary septic localizations were noted at 6 patients: 4 cerebral abscesses, 2 splenic localization, a renal localization and an articular localization. High degree atrioventricular blocks were observed at 3 patients. The recourse to the surgery was frequent (7 patient/9 patient). It was an emergent sugery at 2 patients because of a heart failure. For the others, the indication for surgery was medical failure treatment at a mean delay of 19 days. The evolution was fatal at 5 patients. and the evolution was favorable at the others.Prothetic endocarditis complicated of abscess are serious requiring frequently a prothetic replacement, a very high risked surgery. TEE must be systematic at all patients carrier of prosthesis if they have infectious syndrome in order to carry the early diagnosis of IE and to avoid abcess formation

Epidemiological Aspects of Hepatitis A: Endemicity Patterns and Molecular Epidemiology

Improvements in hygiene and socio-economic conditions in many parts of the world have led to an epidemiological shift in hepatitis A with a transition from high to low endemicity. Consequently, in these areas, higher proportion of symptomatic disease among adolescents resulting in large-scale community outbreaks has been described. In Tunisia, an increase in the average age at the time of infection has been reported, hence resulting in regular outbreaks, especially household and primary school epidemics. Molecular investigation of such outbreaks, based on the determination of viral genotype and genetic relatedness between hepatitis A virus (HAV) strains, is a useful tool to identify the potential source of HAV contamination but also to assess the virus molecular dynamics over time, such as the introduction of a new genotype or a specific clustering of HAV strains according to the geographical origin. In Sfax city, (Center-East of Tunisia), only HAV strains of genotype IA are circulating. In rural areas, HAV infection is still highly endemic with probably a water-borne transmission pattern. Nevertheless, the considerable genetic heterogeneity observed in urban areas highlights the changing pattern of hepatitis A epidemiology in these settings. Further molecular studies are strongly needed to better understand HAV epidemiology in Tunisia

Effects of Within-Person Variability in Spot Urinary Sodium Measurements on Associations With Blood Pressure and Cardiovascular Disease.

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