180 research outputs found

    Development of a method of robust rain gauge network optimization based on intensity-duration-frequency results

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    Based on rainfall intensity-duration-frequency (IDF) curves, fitted in several locations of a given area, a robust optimization approach is proposed to identify the best locations to install new rain gauges. The advantage of robust optimization is that the resulting design solutions yield networks which behave acceptably under hydrological variability. Robust optimization can overcome the problem of selecting representative rainfall events when building the optimization process. This paper reports an original approach based on Montana IDF model parameters. The latter are assumed to be geostatistical variables, and their spatial interdependence is taken into account through the adoption of cross-variograms in the kriging process. The problem of optimally locating a fixed number of new monitoring stations based on an existing rain gauge network is addressed. The objective function is based on the mean spatial kriging variance and rainfall variogram structure using a variance-reduction method. Hydrological variability was taken into account by considering and implementing several return periods to define the robust objective function. Variance minimization is performed using a simulated annealing algorithm. In addition, knowledge of the time horizon is needed for the computation of the robust objective function. A short- and a long-term horizon were studied, and optimal networks are identified for each. The method developed is applied to north Tunisia (area = 21 000 km2). Data inputs for the variogram analysis were IDF curves provided by the hydrological bureau and available for 14 tipping bucket type rain gauges. The recording period was from 1962 to 2001, depending on the station. The study concerns an imaginary network augmentation based on the network configuration in 1973, which is a very significant year in Tunisia because there was an exceptional regional flood event in March 1973. This network consisted of 13 stations and did not meet World Meteorological Organization (WMO) recommendations for the minimum spatial density. Therefore, it is proposed to augment it by 25, 50, 100 and 160% virtually, which is the rate that would meet WMO requirements. Results suggest that for a given augmentation robust networks remain stable overall for the two time horizons

    Chloroformic and Methanolic Extracts of Olea europaea L. Leaves Present Anti-Inflammatory and Analgesic Activities

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    Olea europaea L. is used in traditional medicine in the Mediterranean areas. Its natural products are used in the treatment of different disorders, like fighting fever and some infectious diseases such as malaria, the treatment of arrhythmia, and relief of intestinal spasms. The aim of the current study is to investigate the possible anti-inflammatory and anatinociceptive effects of methanol and chloroformic extracts prepared from leaves of Olea europaea L. The anti-inflammatory and antinociceptive effects of the different extracts of Olea europaea leaves were assessed after intraperitoneal administration into rats and mice, using the carrageenan-induced paw edema model in rats to test the anti-inflammatory effect and the acetic acid-induced writhing in mice to test the analgesic effect. The chloroformic and methanolic leaves extracts, studied at the doses of 50, 100, and 200 mg/kg (Body Weight: BW), exhibited significant dose-dependent anti-inflammatory and analgesic activities. Based on the results obtained, it can be concluded that Olea europaea leaves extracts have anti-inflammatory and antinociceptive effects

    Kyste hydatique cervico mediastinal a propos d’un cas

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    Le kyste hydatique cervico-médiastinal est extrêmement rare même en pays d’endémie. Il se manifeste généralement par une masse cervico-thoracique et il pose un problème délicat de diagnostic. Les auteurs rapportent le cas d’une femme de 53 ans, qui a consulté pour une masse sus claviculaire gauche évoluant depuis une année. Le bilan radiologique avait conclu au début à un magma d’adénopathies cervico-médiastinales. La patiente a bénéficié, alors, d’une cervicotomie exploratrice avec la découverte en per-opératoire d’un kyste hydatique cervico- médiastinal.Mots clé : Kyste hydatique, localisation cervico-médiastinale, imagerie

    Les cellulites cervico-faciales d’origine dentaire: a propos de 150 cas

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    Les cellulites cervico-faciales d’origine dentaire sont des infections des tissus cellulo-adipeux, de la face et du cou, ayant des potentialités extensives pouvant parfois être graves et engager le pronostic vital. Le but de ce travail est d’étudier le profil épidémioclinique et paraclinique de nos patients, d’évaluer leur prise en charge thérapeutique et leur évolution. Notre étude est rétrospective et a porté sur 150 cas de cellulites cervico-faciales d’origine dentaire colligés sur 10 ans entre 1997 et 2006. La prise en charge thérapeutique était médico-hirurgicale. Les cellulites cervico-faciales d’origine dentaire sont une pathologie potentiellement grave dont la prise en charge est coûteuse et les répercussions socio-professionnelles et économiques sont lourdes d’où l’intérêt d’une politique de prévention efficace et ciblée visant à réduire la morbidité liée à ces infections.Mots clés : cellulites cervicale et faciale, infections dentaire, prévention

    Appendagite épiploïque primitive: à propos de cinq cas

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    La torsion de frange épiploïque (ou appendagite) est une pathologie rare qui survient principalement chez les adultes entre 20 et 50 ans.L'incidence de cette pathologie n'est pas réellement connue et elle varie de 2 à 7% chez les patients hospitalisés pour suspicion d'appendicite oude sigmoïdite. Nous rapportons cinq cas d'appendagites dont nous précisons les particularités cliniques, radiologiques et thérapeutiques. Il s'agit de 5 patients dont l'âge moyen est de 34.6 ans (24-55). Le sexe ratio est de 1.5. Le principal motif de consultation était un syndrome douloureux de l'abdomen principalement au niveau de la fosse iliaque droite. L'examen abdominal montrait toujours une sensibilité localisée. La fièvre était présente chez 3 patients. Le bilan biologique révèle un syndrome inflammatoire biologique chez trois patients. Les examens complémentaires radiologiques en particulier échographie abdominale et TDM abdominale ont éliminé formellement une urgence chirurgicale et ont évoqué le diagnostic d'appendagite dans trois cas. Trois patients ont bénéficié d'une coelioscopie diagnostique confirmant le diagnostic  d'appendagite. L'évolution était favorable chez tous les patients. Les appendagites épiploïques primitives sont des étiologies rares et  sous-estimées de syndrome abdominal aigu. Le diagnostic peut être affirmé par imagerie notamment avec le scanner hélicoïdal injecté,  permettant d'instaurer ainsi un traitement médical premier et d'éviter un traitement chirurgical et des hospitalisations excessives

    Osteomyelite atypique ou centrale de la base du crane d’origine sinusienne

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    Introduction : L’ostéomyélitede la base du crâne esttypiquement secondaire à une otite externe nécrosante chez des patients âgés, diabétiques. Elle atteint l’os temporal et est habituellement due au pseudomonasaeruginosa. Dans sa forme atypique, l’ostéomyélite atteint les os sphénoïdal ou occipital sans otite externe associéeet est beaucoup moins fréquente. Le but de cette étude est d’analyser les caractéristiques cliniques et de déterminer les modalités thérapeutiques de l’ostéomyélite nonotologique de la base du crâne.Méthodes : Nous avons revu rétrospectivement deux casd’ostéomyélite atypique de la base du crâne.Résultats : Les deux patients se sont présentés dans un tableau d’altération de l’état général, une asthénie, des céphalées et de la fièvre. Les signes rhinologiques étaient discrets. Aucun des deux patients n’avait de déficit neurologique. L’imagerie avait montré une destruction osseuse, la biologie a objectivé un syndrome infectieux et une biopsie osseuse trans sphénoïdale a confirmé le diagnostic d’ostéomyélite. Un traitement antibiotique prolongé a été instauré et les deux patients ont été guéris sans récidive moyennant un recul de 12 mois.Conclusion : l’atteinte ostéomyélitique centrale de la base du crâne est une affection rare dont la prise en charge passe par un prélèvement osseux précoce et un traitement approprié afin de prévenir ou limiter d’autres complications telles qu’une extension endocrânienne, un empyème, ou la mort.Mots Clés: Ostéomyélite; Base du crâne; sphenoïdite; IRMIntroduction : Skull base osteomyelitis typically arises as a complication of ear infection in older diabetic patients, involves the temporal bone, and has Pseudomonas aeruginosaas the usual pathogen. Atypical skull base osteomyelitis arising from the sphenoid or occipital bones without associated external otitis occurs much less frequently. The purpose of this study was to review the clinical featuresand determine efficacy of treatment for nonotologic osteomyelitis of the skull base.Methods : We retrospectively reviewed two cases of central or atypical skull base osteomyelitis.Results : The two patients presented with asthenia, headache, and fever. No patient presented with neurologic deficits. Contrary to malignant otitis externa, our cases were not preceded by immediate external infections and had normal external ear examinations. One patient had an underlying immunocompromising condition. Imaging demonstrated bone destruction, subsequent microbiological analysis diagnosed infection and a biopsy proved diagnosis of osteomyelitis, a prolonged antibiotic treatment was instored. The two patients were cured with no recurrence of skull base infection over 12-month follow-up period.Conclusion : Central skull base osteomyelitis is a rare disease whose treatment requires an early bone biopsy and appropriate treatment to prevent or limit other complications such as intracranial extension, empyema, or dead.Key Words : Osteomyelitis; Skull base; sphenoïditis; MR

    Basin tectonic history and paleo-physiography of the pelagian platform, northern Tunisia, using vitrinite reflectance data

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    Constraining the thermal, burial and uplift/exhumation history of sedimentary basins is crucial in the understanding of upper crustal strain evolution and also has implications for understanding the nature and timing of hydrocarbon maturation and migration. In this study, we use Vitrinite Reflectance (VR) data to elucidate the paleo‐physiography and thermal history of an inverted basin in the foreland of the Atlasic orogeny in Northern Tunisia. In doing so, it is the primary aim of this study to demonstrate how VR techniques may be applied to unravel basin subsidence/uplift history of structural domains and provide valuable insights into the kinematic evolution of sedimentary basins. VR measurements of both the onshore Pelagian Platform and the Tunisian Furrow in Northern Tunisia are used to impose constraints on the deformation history of a long‐lived structural feature in the studied region, namely the Zaghouan Fault. Previous work has shown that this fault was active as an extensional structure in Lower Jurassic to Aptian times, before subsequently being inverted during the Late Cretaceous Eocene Atlas I tectonic event and Upper Miocene Atlas II tectonic event. Quantifying and constraining this latter inversion stage, and shedding light on the roles of structural inheritance and the basin thermal history, are secondary aims of this study. The results of this study show that the Atlas II WNW‐ESE compressive event deformed both the Pelagian Platform and the Tunisian Furrow during Tortonian‐Messinian times. Maximum burial depth for the Pelagian Platform was reached during the Middle to Upper Miocene, i.e. prior to the Atlas II folding event. VR measurements indicate that the Cretaceous to Ypresian section of the Pelagian Platform was buried to a maximum burial depth of ~3 km, using a geothermal gradient of 30°C/km. Cretaceous rock samples VR values show that the hanging wall of the Zaghouan Fault was buried to a maximum depth of <2 km. This suggests that a vertical km‐scale throw along the Zaghouan Fault pre‐dated the Atlas II shortening, and also proves that the fault controlled the subsidence of the Pelagian Platform during the Oligo‐Miocene. Mean exhumation rates of the Pelagian Platform throughout the Messinian to Quaternary were in the order of 0.3 mm/year. However, when the additional effect of Tortonian‐Messinian folding is accounted for, exhumation rates could have reached 0.6-0.7 mm/year

    Effects of Precursor Concentration and Acidic Sulfate in Aqueous Glyoxal−OH Radical Oxidation and Implications for Secondary Organic Aerosol

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    Previous experiments demonstrated that aqueous OH radical oxidation of glyoxal yields low-volatility compounds. When this chemistry takes place in clouds and fogs, followed by droplet evaporation (or if it occurs in aerosol water), the products are expected to remain partially in the particle phase, forming secondary organic aerosol (SOA). Acidic sulfate exists ubiquitously in atmospheric water and has been shown to enhance SOA formation through aerosol phase reactions. In this work, we investigate how starting concentrations of glyoxal (30−3000 μM) and the presence of acidic sulfate (0−840 μM) affect product formation in the aqueous reaction between glyoxal and OH radical. The oxalic acid yield decreased with increasing precursor concentrations, and the presence of sulfuric acid did not alter oxalic acid concentrations significantly. A dilute aqueous chemistry model successfully reproduced oxalic acid concentrations, when the experiment was performed at cloud-relevant concentrations (glyoxal <300 μM), but predictions deviated from measurements at increasing concentrations. Results elucidate similarities and differences in aqueous glyoxal chemistry in clouds and in wet aerosols. They validate for the first time the accuracy of model predictions at cloud-relevant concentrations. These results suggest that cloud processing of glyoxal could be an important source of SOA

    Harnessing inter-disciplinary collaboration to improve emergency care in low- and middle-income countries (LMICs): results of research prioritisation setting exercise

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    Background More than half of deaths in low- and middle-income countries (LMICs) result from conditions that could be treated with emergency care - an integral component of universal health coverage (UHC) - through timely access to lifesaving interventions. Methods The World Health Organization (WHO) aims to extend UHC to a further 1 billion people by 2023, yet evidence supporting improved emergency care coverage is lacking. In this article, we explore four phases of a research prioritisation setting (RPS) exercise conducted by researchers and stakeholders from South Africa, Egypt, Nepal, Jamaica, Tanzania, Trinidad and Tobago, Tunisia, Colombia, Ethiopia, Iran, Jordan, Malaysia, South Korea and Phillipines, USA and UK as a key step in gathering evidence required by policy makers and practitioners for the strengthening of emergency care systems in limited-resource settings. Results The RPS proposed seven priority research questions addressing: identification of context-relevant emergency care indicators, barriers to effective emergency care; accuracy and impact of triage tools; potential quality improvement via registries; characteristics of people seeking emergency care; best practices for staff training and retention; and cost effectiveness of critical care – all within LMICs. Conclusions Convened by WHO and facilitated by the University of Sheffield, the Global Emergency Care Research Network project (GEM-CARN) brought together a coalition of 16 countries to identify research priorities for strengthening emergency care in LMICs. Our article further assesses the quality of the RPS exercise and reviews the current evidence supporting the identified priorities
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