385 research outputs found
Pacific subsurface ocean temperature as a long-rangepredictor of South China tropical cyclone landfall
Seasonal forecasts of the tropical cyclones which frequently make landfall along the densely populated South China coast are highly desirable. Here, we analyse observations of landfalling tropical cyclones in South China and of subsurface ocean temperatures in the Pacific warm pool region, and identify the possibility of forecasts of South China tropical cyclone landfall a year ahead. Specifically, we define a subsurface temperature index, subNiño4, and build a predictive model based on subNiño4 anomalies with a robust double cross-validated forecast skill against climatology of 23%, similar in skill to existing forecasts issued much later in the spring. We suggest that subNiño4 ocean temperatures precede the surface El Niño/Southern Oscillation state by about 12 months, and that the zonal shifts in atmospheric heating then change mid-level winds to steer tropical cyclones towards landfall in South China. We note that regional subsurface ocean temperature anomalies may permit atmospheric predictions in other locations at a longer range than is currently thought possible
Long memory impact of ocean mesoscale temperature anomalies on tropical cyclone size
Mesoscale ocean temperature anomalies modify a tropical cyclone (TC). Through a modeling study we show that, while the maximum wind speed is rapidly restored after the TC passes a warm‐ or cold‐ (eddy size) sea surface temperature (SST) anomaly, the storm size changes are more significant and persistent. The radius of gale force winds and integrated kinetic energy (IKE) can change by more than 10% per degree and this endures several days after crossing an SST anomaly. These properties have a long memory of the impact from the ocean fluxes and depend on the integrated history of SST exposure. They are found to be directly proportional to the storm total precipitation. Accurate continuous forecast of the SST along the track may therefore be of central importance to improving predictions of size and IKE, while instantaneous local SST near the TC core is more important for the forecast of maximum wind speed
Mobility of Chromium and Tin Associated with Geochemical Dynamics in Groundwater in Meboudja Plain
AbstractIn the region of Sidi Amar Annaba South. Storage of industrial waste from the Arcelor-Mittal steel complex directly on the floor produced an infiltration of heavy metals to the under saturated and groundwater area. To know the exact origin of some pollutants and their evolution in time, monthly monitoring of water chemistry (potential hydrogen, potential of oxydo-reduction, temperature, conductivity, Oxygen, Calcium, Magnesium, Sodium, Potassium, Chlorine, sulfate, bicarbonate, Nitrate, Strontium, total Chrome, total Tin) was performed on wells for water cycle.Statistical analysis shows a common origin of chromium and tin that would be due to electroplating waste. The temporal evolution of these elements highlights the influence of several factors (potential hydrogen, potential of oxydo-reduction, rainfall and pumping) in the dissolution of these species and the evolution of the dominant aqueous species. There presentation of water points on the Eh-pH equilibrium diagram indicates that chromium may appear in the water table in two complex forms, trivalent and hexavalent by against the tin is in the hexavalent form
Preparation of superhydrophobic and self-cleaning polysulfone non-wovens by electrospinning: influence of process parameters on morphology and hydrophobicity
Electrospinning is used to prepare hydrophobic and self-cleaning polysulfone (PSf) surfaces. The effects of PSf concentration in Dimethylformamide (DMF) solvent and electrospinning process parameters on the surface structure and hydrophobicity are investigated. The experimental results show that depending on PSf concentration, three types of morphologies are obtained: beads, beads-on-strings, and free-beads fibers. The surface hydrophobicity depends mainly on the resultant surface morphology, and the existence of beads increases hydrophobicity. The contact angle (CA) is found to increase from 73° for smooth PSf surface to more than 160° for surfaces formed by electrospinning. Moreover, the contact angle hysteresis (CAH) was generally less than 10° for all the chemistries. It is noted that increasing the PSf concentration leads to the formation of beads-on-string and free-beads fiber structures; this morphological change is accompanied by a reduction in the contact angle. Surface structures are found to be more sensitive to electrospinning feed rate than to electrospinning voltage; however, these two parameters have a negligible influence on the hydrophobicity. Porosity measurements of different chemistries show an average pore size in the range 3–8 microns. The thickness of PSf mats was variable, from as low as 10 μm to as high as 70 μm.King Fahd University of Petroleum and Minerals (KFUPM-MIT Project No. R16-DMN-11)King Abdulaziz City of Science and Technology (Saudia Arabia) (Project No. 11-ADV2134- 04
Fistule carotido-caverneuse post-traumatique
Introduction : La fistule carotido-caverneuse (FCC) est une complication rare, mais grave des traumatismes craniofaciaux pouvant engager le pronostic fonctionnel oculaire et le pronostic vital. elle réalise une communication anormale entre le système artériel carotidien et le sinus caverneux.Buts : Rapporter un cas de FCC directe post-traumatique et étudier les aspects cliniques, diagnostiques et thérapeutiques de cette pathologie.Observation : Nous rapportons un cas de FCC apparue dans les suites d’un traumatisme craniofacial et survenue chez un homme de 25 ans ayant été victime d’un accident de la voie publique. Le diagnostic a été suspecté devant l’apparition, au 19ème jour d’hospitalisation, d’une exophtalmie unilatérale gauche pulsatile associée à un important chémosis et à une pupille aréflectique. Une artériographie cérébrale pratiquée 9 jours après la constatation de l’exophtalmie a objectivé une large FCC gauche. Une embolisation au moyen de deux ballonnets intravasculaires largables et de l’injection de colle biologique a été réalisée au même temps sans incidents permettant d’obtenir l’occlusion complète de la fistule. L’évolution a été marquée par la régression de l’exophtalmie et du chémosis et par l’amélioration partielle de l’acuité visuelle.Conclusion : Le traitement des FCC est urgent et est principalement basé sur la neuroradiologie interventionnelle. en effet, l’angiographie cérébrale constitue l’examen clé et possède un double intérêt diagnostique et thérapeutique.Mots clés : fistule carotido-caverneuse, traumatisme craniofacial, artériographie cérébrale, embolisation
A long survival of a patient with brain metastasis of unknown site of the primary tumor
Eighty percent of brain metastases (BM) are diagnosed in patients with known primary site of cancer. BM of unknown primary represents a difficult diagnosis. In up to 15% of patients with BM, the site of the primary tumor will not be detected despite investigations. The prognosis of this entity is very poor. We report here a case of a long survival of a patient with brain metastasis of unknown primary. The conclusion that can be drawn is that within BM of unknown primary exist patients with a very good prognosis that must be collected and published in order to base recommendations
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