110 research outputs found
Protocole de routage basé sur des passerelles mobiles pour un accès Internet dans les réseaux véhiculaires
La rapide progression des technologies sans fil au cours de ces dernières années a vu
naître de nouveaux systèmes de communication dont les réseaux véhiculaires. Ces réseaux
visent à intégrer les nouvelles technologies de l’information et de la communication dans le
domaine automobile en vue d’améliorer la sécurité et le confort sur le réseau routier. Offrir un accès Internet aux véhicules et à leurs occupants peut sans doute aider à anticiper
certains dangers sur la route tout en rendant plus agréables les déplacements à bord des véhicules. Le déploiement de ce service nécessite que des messages soient échangés entre les véhicules. Le routage constitue un élément crucial dans un réseau, car définissant la façon dont les différentes entités échangent des messages. Le routage dans les VANETS constitue un grand défi car ces derniers sont caractérisés par une forte mobilité entraînant une topologie très dynamique.
Des protocoles ont été proposés pour étendre Internet aux réseaux véhiculaires. Toutefois,
la plupart d’entre eux nécessitent un coût élevé de messages de contrôle pour
l’établissement et le maintien des communications. Ceci a pour conséquence la saturation de la bande passante entrainant ainsi une baisse de performance du réseau.
Nous proposons dans ce mémoire, un protocole de routage qui s’appuie sur des
passerelles mobiles pour étendre Internet aux réseaux véhiculaires. Le protocole prend en compte la mobilité des véhicules et la charge du réseau pour l’établissement et le maintien des routes.The fast progression of wireless technologies has motivated the emergence of new communications system called VANETS (Vehicular Adhoc Networks). VANETS enable
vehicles on the roadway to communicate with each other and with road infrastructure using
wireless capabilities. The applications of VANETS include improving safety and comfort
on the road. For example, by providing Internet to vehicles, traveling can be safer and more comfortable. To provide Internet connectivity, messages need to be exchanged between the vehicles. However, it is hard to design an efficient routing protocol for connecting vehicles to Internet with a reasonable cost due to high mobility in VANETS.
Although, several existing routing protocols have been proposed in the open literature to
extend Internet to VANETS, they generate considerable overhead. This leads to unfairly
consumption of bandwidth decreasing network performance.
We design a routing protocol to connect vehicles to Internet through mobile gateways
with the objective to make efficient use of the network bandwidth. Indeed, the protocol
significantly reduces the communication overhead required to establish and maintain the routes relying on the mobility of the gateways and the network’s load
Indications et résultats de la chirurgie de résection des bulles d’emphysème pulmonaire
La chirurgie d'exérèse des bulles ou bullectomie, principal moyen thérapeutique dans la prise en charge des bulles d'emphysème pulmonaire, est généralement réservée aux patients dont les bulles sont compliquées ou, sont à l'origine d'une dyspnée invalidante. Le but de notre étude était de déterminer les indications de la bullectomie et d'évaluer les résultats de cette chirurgie dans notre service. Nous avons mené une étude rétrospective descriptive de 24 patients (23 hommes et 1 femme), dont la moyenne d'âge était de 49 ans, et qui ont bénéficié d'une bullectomie entre 2004 et 2013. Les données recueillies étaient les facteurs favorisant la survenue d'un emphysème bulleux, les circonstances de découverte de la bulle, les données des examens radiologiques, les données de l'évaluation fonctionnelle respiratoire et cardiovasculaire, les données de la technique de la bullectomie, les données de l'évaluation clinique et fonctionnelle post opératoire. Le taux de morbidité était de 37,5%. La principale complication était la fuite aérienne persistante (7 cas). Un patient est décédé au 2e jour post opératoire suite à une insuffisance respiratoire aiguë. La durée moyenne de suivi était de 26 mois. Durant ce suivi, nous avons observé une amélioration de la dyspnée chez tous les patients et nous n'avons noté aucune complication. La bullectomie est une technique chirurgicale efficace, fiable et sûre qui peut permettre aux patients d'avoir une meilleure qualité de vie pendant quelques années
Le pneumothorax spontané comme une manifestation évolutive de la polyarthrite rhumatoide: à propos d’une observation clinique et revue de la litterature
La polyarthrite rhumatoïde est une maladie systémique inflammatoire caractérisée par une destruction des synoviales articulaires et des lésions systémiques extra articulaires. Les nodules pulmonaires font partie de ces dernières. Leur évolution peut aboutir à un pneumothorax spontané. Nous rapportons le cas d'un adulte jeune au long passé de polyarthrite rhumatoïde qui a présenté deux épisodes de pneumothorax spontané. Il était admis dans notre service, en urgence, pour un pneumothorax droit spontané et massif sur terrain de polyarthrite rhumatoïde au stade de déformation. Il était sous méthotrexate. La radiographie standard du thorax et la tomodensitométrie montraient un décollement pleural complet droit, des nodules et des images excavées sur les deux champs pulmonaires. Il a bénéficié d'un drainage thoracique aspiratif permettant une bonne ré-expansion pulmonaire. Le pneumothorax spontané constitue une manifestation rare des lésions pulmonaire de la polyarthrite rhumatoïde. Il s'agit le plus souvent d'une manifestation évolutive de la maladie mais aussi une circonstance de découverte de cette dernière. L'implication des immunosuppresseurs reste à être prouvée. Ainsi la polyarthrite rhumatoïde doit être considérée dans la recherche étiologique d'un pneumothorax spontané.Pan African Medical Journal 2015; 2
Everglades Ecological Forecasting II: Utilizing NASA Earth Observations to Enhance the Capabilities of Everglades National Park to Monitor & Predict Mangrove Extent to Aid Current Restoration Efforts
Mangroves act as a transition zone between fresh and salt water habitats by filtering and indicating salinity levels along the coast of the Florida Everglades. However, dredging and canals built in the early 1900s depleted the Everglades of much of its freshwater resources. In an attempt to assist in maintaining the health of threatened habitats, efforts have been made within Everglades National Park to rebalance the ecosystem and adhere to sustainably managing mangrove forests. The Everglades Ecological Forecasting II team utilized Google Earth Engine API and satellite imagery from Landsat 5, 7, and 8 to continuously create land-change maps over a 25 year period, and to allow park officials to continue producing maps in the future. In order to make the process replicable for project partners at Everglades National Park, the team was able to conduct a supervised classification approach to display mangrove regions in 1995, 2000, 2005, 2010 and 2015. As freshwater was depleted, mangroves encroached further inland and freshwater marshes declined. The current extent map, along with transition maps helped create forecasting models that show mangrove encroachment further inland in the year 2030 as well. This project highlights the changes to the Everglade habitats in relation to a changing climate and hydrological changes throughout the park
Right-heart infective endocarditis: apropos of 10 cases
The prevalence and characteristics of right heart endocarditis in Africa are not well known. The aim of this study was to describe the epidemiological, clinical and laboratory profiles of patients with right-heart infective endocarditis. This was a 10-year retrospective study conducted in 2 cardiology departments in Dakar, Senegal. All patients who met the diagnosis of right heart infective endocarditis according to the Duke's criteria were included. We studied the epidemiological, clinical as well as their laboratory profiles. There were 10 cases of right-heart infective endocarditis representing 3.04% of cases of infective endocarditis. There was a valvulopathy in 3 patients, an atrial septal defect in 1 patient, parturiency in 2 patients and the presence of a pacemaker in one patient. Anaemia was present in 9 patients whilst leukocytosis in 6 patients. The port of entry was found to be oral in three cases, ENT in one case and urogenital in two cases. Apart from one patient with vegetations in the tricuspid and pulmonary valves, the rest had localized vegetation only at the tricuspid valve. However, blood culture was positive in only three patients. There was a favorable outcome after antibiotic treatment in 4 patients with others having complications; three cases of renal impairment, two cases of heart failure and one case of pulmonary embolism. There was one mortality. Right heart infective endocarditis is rare but associated with potentially fatal complications.Pan African Medical Journal 2015; 2
Mass testing and treatment for malaria followed by weekly fever screening, testing and treatment in Northern Senegal: feasibility, cost and impact.
BACKGROUND NlmCategory: BACKGROUND content:
Population-wide interventions using malaria testing and
treatment might decrease the reservoir of Plasmodium falciparum
infection and accelerate towards elimination. Questions remain
about their effectiveness and evidence from different
transmission settings is needed. - Label: METHODS NlmCategory:
METHODS content: "A pilot quasi-experimental study to evaluate a
package of population-wide test and treat interventions was
conducted in six health facility catchment areas (HFCA) in the
districts of Kanel, Lingu\xC3\xA8re, and Ran\xC3\xA9rou
(Senegal). Seven adjacent HFCAs were selected as comparison.
Villages within the intervention HFCAs were stratified according
to the 2013 incidences of passively detected malaria cases, and
those with an incidence\xE2\x80\x89\xE2\x89\xA5\xE2\x80\x8915
cases/1000/year were targeted for a mass test and treat (MTAT)
in September 2014. All households were visited, all consenting
individuals were tested with a rapid diagnostic test (RDT), and,
if positive, treated with dihydroartemisinin-piperaquine. This
was followed by weekly screening, testing and treatment of fever
cases (PECADOM++) until the end of the transmission season in
January 2015. Villages with lower incidence received only
PECADOM++ or case investigation. To evaluate the impact of the
interventions over that transmission season, the incidence of
passively detected, RDT-confirmed malaria cases was compared
between the intervention and comparison groups with a
difference-in-difference analysis using negative binomial
regression with random effects on HFCA." - Label: RESULTS
NlmCategory: RESULTS content: "During MTAT, 89% (2225/2503) of
households were visited and 86% (18,992/22,170) of individuals
were tested, for a combined 77% effective coverage. Among those
tested, 291 (1.5%) were RDT positive (range 0-10.8 by village),
of whom 82% were\xE2\x80\x89<\xE2\x80\x8920\xC2\xA0years old
and 70% were afebrile. During the PECADOM++ 40,002 visits were
conducted to find 2784 individuals reporting fever, with an RDT
positivity of 6.5% (170/2612). The combination of interventions
resulted in an estimated 38% larger decrease in malaria case
incidence in the intervention compared to the comparison group
(adjusted incidence risk ratio\xE2\x80\x89=\xE2\x80\x890.62, 95%
CI 0.45-0.84, p\xE2\x80\x89=\xE2\x80\x890.002). The cost of the
MTAT was $14.3 per person." - Label: CONCLUSIONS NlmCategory:
CONCLUSIONS content: It was operationally feasible to conduct
MTAT and PECADOM++ with high coverage, although PECADOM++ was
not an efficient strategy to complement MTAT. The modest impact
of the intervention package suggests a need for alternative or
complementary strategies
Ascite fébrile chez la femme, ne pas méconnaitre une tumeur de Krukenberg
Les tumeurs de Krukenberg (TK) se définissent comme des métastases ovariennes d'un cancer, le plus souvent digestif. Elles représentent 5 à 15% des tumeurs malignes ovariennes. Notre objectif était de décrire les caractéristiques épidémiologiques, diagnostiques, thérapeutiques et évolutives.Nous rapportons deux observations de tumeur de Krukenberg découvertes à l'occasion de l'exploration d'une ascite fébrile.Il s'agit de deux patientes multipares âgées respectivement de 32 ans et 50 ans. Les signes d'appel étaient essentiellement digestifs. La découverte de ces métastases ovariennes était survenue à distance des foyers primitifs. L'atteinte des ovaires était bilatérale dans le premier cas et unilatérale droite dans le second cas. Le diagnostic est apporté par la tomodensitométrie abdominopelvienne dans les deux cas. La fibroscopie oesogastroduodénale avait permis de retrouver le foyer primitif respectivement sous forme d'un processus bourgeonnant et d'un ulcère en position antrale avec des stigmates d'hémorragies. L'examen anatomopathologique des biopsies réalisées mettait en évidence un adénocarcinome tubuleux moyennement différencié de l'estomac avec composante mucineuse dans la première observation et un adénocarcinome de type intestinal moyennement différencié dans la seconde. Le traitement chirurgical confirme le diagnostic histologique. Dans notre série, le traitement n'a pu être que symptomatique en raison de l'existence constante d'une carcinose péritonéale et de l'altération profonde de l'état général. Les deux patientes ont été confiées à l'institut de cancérologie pour une chimiothérapie palliative. La première est décédée 1 mois après. La tumeur de Krukenberg est une maladie rare. Le diagnostic est facilité par la radiologie et confirmé par l'histologie. Son pronostic demeure encore très sombre. Le seul espoir réside dans les mesures préventives.Key words: Métastases ovariennes, tumeur de Krukenberg, pronostic sombre
Mass testing and treatment for malaria followed by weekly fever screening, testing and treatment in Northern Senegal: feasibility, cost and impact.
BACKGROUND: Population-wide interventions using malaria testing and treatment might decrease the reservoir of Plasmodium falciparum infection and accelerate towards elimination. Questions remain about their effectiveness and evidence from different transmission settings is needed. METHODS: A pilot quasi-experimental study to evaluate a package of population-wide test and treat interventions was conducted in six health facility catchment areas (HFCA) in the districts of Kanel, Linguère, and Ranérou (Senegal). Seven adjacent HFCAs were selected as comparison. Villages within the intervention HFCAs were stratified according to the 2013 incidences of passively detected malaria cases, and those with an incidence ≥ 15 cases/1000/year were targeted for a mass test and treat (MTAT) in September 2014. All households were visited, all consenting individuals were tested with a rapid diagnostic test (RDT), and, if positive, treated with dihydroartemisinin-piperaquine. This was followed by weekly screening, testing and treatment of fever cases (PECADOM++) until the end of the transmission season in January 2015. Villages with lower incidence received only PECADOM++ or case investigation. To evaluate the impact of the interventions over that transmission season, the incidence of passively detected, RDT-confirmed malaria cases was compared between the intervention and comparison groups with a difference-in-difference analysis using negative binomial regression with random effects on HFCA. RESULTS: During MTAT, 89% (2225/2503) of households were visited and 86% (18,992/22,170) of individuals were tested, for a combined 77% effective coverage. Among those tested, 291 (1.5%) were RDT positive (range 0-10.8 by village), of whom 82% were < 20 years old and 70% were afebrile. During the PECADOM++ 40,002 visits were conducted to find 2784 individuals reporting fever, with an RDT positivity of 6.5% (170/2612). The combination of interventions resulted in an estimated 38% larger decrease in malaria case incidence in the intervention compared to the comparison group (adjusted incidence risk ratio = 0.62, 95% CI 0.45-0.84, p = 0.002). The cost of the MTAT was $14.3 per person. CONCLUSIONS: It was operationally feasible to conduct MTAT and PECADOM++ with high coverage, although PECADOM++ was not an efficient strategy to complement MTAT. The modest impact of the intervention package suggests a need for alternative or complementary strategies
Liver Stiffness Measurement and Biochemical Markers in Senegalese Chronic Hepatitis B Patients with Normal ALT and High Viral Load
Despite the high prevalence of chronic hepatitis B (CHB) in Africa, few studies have been performed among African patients. We sought to evaluate liver stiffness measurement by FibroScan® (LSM) and two biochemical scores (FibroTest®, Fibrometer®) to diagnose liver fibrosis in Senegalese CHB patients with HBV plasma DNA load ≥3.2 log(10) IU/mL and normal alanine aminotransferase (ALT) values.LSM and liver fibrosis biochemical markers were performed on 225 consecutive HBV infected Senegalese patients with high viral load. Patients with an LSM range between 7 and 13 kPa underwent liver biopsy (LB). Two experienced liver pathologists performed histological grading using Metavir and Ishak scoring.225 patients were evaluated (84% male) and LB was performed in 69 patients, showing F2 and F3 fibrosis in 17% and 10% respectively. In these patients with a 7-13 kPa range of LSM, accuracy for diagnosis of significant fibrosis according to LB was unsatisfactory for all non-invasive markers with AUROCs below 0.70. For patients with LSM values below 7 kPa, FibroTest® (FT), and Fibrometer® (FM) using the cut-offs recommended by the test promoters suggested a fibrosis in 18% of cases for FT (8% severe fibrosis) and 8% for FM. For patients with LSM values greater than 13 kPa, FT, FM suggested a possible fibrosis in 73% and 70%, respectively.In highly replicative HBV-infected African patients with normal ALT and LSM value below 13 kPa, FibroScan®, FibroTest® or Fibrometer® were unsuitable to predict the histological liver status of fibrosis
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