A Probabilistic Assessment Approach for Wind Turbine-Site Matching

This article provides a new methodology for wind turbine-site matching by using a probabilistic approach. The random behavior of the wind speed climate and the uncertainties of wind turbine characteristics are important to take into account in models used to evaluate the performance of the wind turbine. The proposed formulation of the wind turbine-site matching is derived based on the probabilistic reliability assessment approach. It was experimented using different power curve approximation models, for different random conditions, using time series of wind speed in two sites in Morocco: Dakhla and Essaouira. A comparison based on methods used in literature for the estimation of two-parameter of the Weibull function to fit the wind speed distribution is also carried out. The results revealed that the introduced performance indicators are less sensitive to the models used to approximate the wind power curves compared to the deterministic conventional indicator that leads to different rankings and problems of over-sizing or under-sizing. However, those performance indicators are more sensitive to the variation of the wind speed distribution parameter’s and can help on accurately estimate the wind power. Moreover, the proposed formulation allows a global sensitivity analysis using Sobol’s indices to observe the influence of each input parameter on the observed variances of the performance of a wind turbine. A numerical application illustrates the interpretation of sensitivity indices and shows the impact of the wind speed and the rated wind speed on the variance of the wind turbine performance. This method can help wind energy developers and manufacturers to optimally select WTGs for their future project and accurately forecast the performance of their WTGs for monitoring and maintenance scheduling under uncertainty

A Bayesian Regularized Artificial Neural Network for Up-Scaling Wind Speed Profile

Maximizing gains from wind energy potential is the principle objective of the wind power sector. Consequently, wind tower size is radically increasing. However, choosing an appropriate wind turbine for a selected site requires having an accurate estimation of vertical wind profile. This is also imperative from the cost and maintenance strategy point of view. Installing tall towers or other expensive devices such as LIDAR or SODAR raises the costs of a wind power project. In this work, we aim to investigate the ability of a Neural Network trained using the Bayesian Regularization technique to estimate wind speed profile up to a height of 100m based on knowledge of wind speed at lower heights. Results show that the proposed approach can achieve satisfactory predictions and prove the suitability of the proposed method for generating wind speed profile and probability distributions based on knowledge of wind speed at lower heights

Severe Tricuspid Valve Endocarditis Related to Tunneled Catheters in Chronic Hemodialysis Patients: When Should the Catheter be Removed?

Introduction: Hemodialysis (HD) patients are predisposed to infective endocarditis (IE) mainly due to repeated manipulation of the vascular access. However, catheter seeding and IE may also result from a distant infection site.Case series: A diabetic patient who was maintained on regular HD through a permanent catheter in the right internal jugular vein presented with septicemia of urinary origin due to Pseudomonas aeruginosa. He was treated with injectable antibiotics for 15 days. Few days after the end of the treatment period he presented with inflammation of the catheter exit site. Blood cultures revealed Pseudomonas aeruginosa and echocardiography showed a large vegetation on the tricuspid valve, confirming the diagnosis of IE. The patient improved after catheter removal and treatment with ceftazidime, vancomycin and amikacin. Another patient who was maintained on chronic HD through a tunneled catheter in the right internal jugular vein presented with a limited infection in the sub-cutaneous tunnel of the catheter that improved after treatment with injectable antibiotics. Two months later, he presented with severe sepsis without signs of local infection of the catheter. Chest radiography showed right sided infiltrates. Injectable antibiotic therapy was given without improvement. Blood cultures were negative but echocardiography showed a large tricuspid valve vegetation. Antibiotic regimen was modified to include vancomycin, amikacin and ceftazidime and the catheter was removed. Unfortunately, the patient died two days after diagnosing IE.Conclusion: catheter seeding and IE may be a consequence of sepsis originating away from the HD catheter site. Tunneled catheters may need to be pre-emptively removed in such situations to prevent serious IE.Keywords: Hemodialysis; Infective Endocarditis; Tricuspid Valv

Évaluation des compétences pratiques en fin de deuxième cycle des études médicales : exemple du drainage du bas appareil urinaire

IntroductionLe drainage vésical peut, mal pratiqué, être iatrogène en se compliquant notamment d’infections et de traumatismes de l’appareil urinaire. Cette étude a pour objectif de déterminer la capacité des étudiants en médecine de fin de deuxième cycle à pratiquer les différents moyens de drainage des urines. Matériel et méthodes Entre janvier et mars 2007, un questionnaire d’autoévaluation des compétences de drainage urinaire a été envoyé par mail à un échantillon représentatif d’étudiants en médecine en dernière année d’externat, soit deux mois avant l’épreuve de l’examen national classant. Résultats Deux cent soixante-dix-sept réponses ont été reçues et analysées. Soixante-douze étudiants (26 %) jugeaient qu’ils maîtrisaient le cathétérisme urétrovésical chez l’homme et 106 étudiants (38,3 %) chez la femme à la fin de leur externat. Soixante et onze étudiants sur les 277 (25,5 %) avaient effectué un stage en urologie au cours de leur cursus. Parmi eux, 53,5 % estimaient acquis le sondage à demeure (SAD) chez l’homme (p < 0,001) et 39 (54,9 %) chez la femme (p < 0,001). Soixante-treize étudiants (26,4 %) estimaient qu’ils maîtrisaient le sondage minute d’une femme ou d’un homme et un seul considérait la pose de cathéter sus-pubien comme acquis. Conclusion L’apprentissage des gestes de drainage urinaire est enseigné de façon inappropriée au cours des études médicales puisque de jeunes médecins se sentent incapables de les reproduire au terme de leur externat. Cela est critiquable, car le sondage doit pouvoir être réalisé par tous médecins non urologues dans leur pratique quotidienne, notamment en terrain hospitalier. Cette étude doit mener à une réflexion sur l’amélioration de l’enseignement des gestes pratiques médicaux essentiels pendant l’externat

Comparative analysis for wind resource assessment : Bayesian Regularization and Levenberg-Marquardt Training Algorithm for Neural Network

International audienc

Applied Bayesian regularized artificial neural network based approach for up-scaling wind speed profil and distribution

International audienc

Determination of optimal drug dose and light dose index to achieve minimally invasive focal ablation of localised prostate cancer using WST11-vascular-targeted photodynamic (VTP) therapy

Objective: To determine the optimal drug and light dose for prostate ablation using WST11 (TOOKAD® Soluble) for vascular-targeted photodynamic (VTP) therapy in men with low-risk prostate cancer. Patients and Methods: In all, 42 men with low-risk prostate cancer were enrolled in the study but two who underwent anaesthesia for the procedure did not receive the drug or light dose. Thus, 40 men received a single dose of 2, 4 or 6 mg/kg WST11 activated by 200 J/cm light at 753 nm. WST11 was given as a 10-min intravenous infusion. The light dose was delivered using cylindrical diffusing fibres within hollow plastic needles positioned in the prostate using transrectal ultrasonography (TRUS) guidance and a brachytherapy template. Magnetic resonance imaging (MRI) was used to assess treatment effect at 7 days, with assessment of urinary function (International Prostate Symptom Score [IPSS]), sexual function (International Index of Erectile Function [IIEF]) and adverse events at 7 days, 1, 3 and 6 months after VTP. TRUS-guided biopsies were taken at 6 months. Results: In all, 39 of the 40 treated men completed the follow-up. The Day-7 MRI showed maximal treatment effect (95% of the planned treatment volume) in men who had a WST11 dose of 4 mg/kg, light dose of 200 J/cm and light density index (LDI) of >1. In the 12 men treated with these parameters, the negative biopsy rate was 10/12 (83%) at 6 months, compared with 10/26 (45%) for the men who had either a different drug dose (10 men) or an LDI of <1 (16). Transient urinary symptoms were seen in most of the men, with no significant difference in IPSS score between baseline and 6 months after VTP. IIEF scores were not significantly different between baseline and 6 months after VTP. Conclusion: Treatment with 4 mg/kg TOOKAD Soluble activated by 753 nm light at a dose of 200 J/cm and an LDI of >1 resulted in treatment effect in 95% of the planned treatment volume and a negative biopsy rate at 6 months of 10/12 men (83%)

Fatty acid profile in peri-prostatic adipose tissue and prostate cancer aggressiveness in African-Caribbean and Caucasian patients

BACKGROUND: Genetic and nutritional factors have been linked to the risk of aggressive prostate cancer (PCa). The fatty acid (FA) composition of peri-prostatic adipose tissue (PPAT), which reflects the past FA intake, is potentially involved in PCa progression. We analysed the FA composition of PPAT, in correlation with the ethno-geographical origin of the patients and markers of tumour aggressiveness. METHODS: From a cohort of 1000 men treated for PCa by radical prostatectomy, FA composition of PPAT was analysed in 156 patients (106 Caucasians and 50 African-Caribbeans), 78 with an indolent tumour (ISUP group 1 + pT2 + PSA &lt;10 ng/mL) and 78 with an aggressive tumour (ISUP group 4-5 + pT3). The effect of FA extracted from PPAT on in-vitro migration of PCa cells DU145 was studied in 72 patients, 36 Caucasians, and 36 African-Caribbeans. RESULTS: FA composition differed according to the ethno-geographical origin. Linoleic acid, an essential n-6 FA, was 2-fold higher in African-Caribbeans compared with Caucasian patients, regardless of disease aggressiveness. In African-Caribbeans, the FA profile associated with PCa aggressiveness was characterised by low level of linoleic acid along with high levels of saturates. In Caucasians, a weak and negative association was observed between eicosapentaenoic acid level (an n-3 FA) and disease aggressiveness. In-vitro migration of PCa cells using PPAT from African-Caribbean patients was associated with lower content of linoleic acid. CONCLUSION: These results highlight an important ethno-geographical variation of PPAT, in both their FA content and association with tumour aggressiveness

Enseignement et perception de l’urologie à la fin du deuxième cycle des études médicales : état des lieux

Objectifs Déterminer la perception de l’urologie par les étudiants en fin de deuxième cycle des études médicales (DCEM) et connaître leurs supports d’enseignement. Matériel et méthodes Un auto-questionnaire a été diffusé par internet à 1600 étudiants de 16 facultés au cours de leur dernier semestre de DCEM. Résultats Au total, 590 réponses ont été reçues (36,8 %). Dans notre population, 70,2 % des étudiants étaient des femmes. Parmi eux, 24,1 % avaient fait un stage en urologie. L’urologie était considérée comme une discipline médicale, chirurgicale et médicochirurgicale, respectivement par 3,7 %, 37,8 % et 58 % d’entre eux. L’urologie était considérée comme une discipline très importante, importante, peu importante et pas importante par 5,1 %, 54,4 %, 37,5 % et 2,4 % d’entre eux. Les supports d’enseignement les plus utilisés pour préparer l’examen national classant (ENC) étaient les polycopiés d’internat (45,3 %), les conférences d’internat (43,7 %), le polycopié national du collège d’Urologie (38,6 %) et les cours dispensés à la faculté (32 %). Les items d’urologie les mieux assimilés étaient les pathologies lithiasiques (86,3 %), les troubles urinaires du bas appareil (76,3 %) et les cancers urologiques (56,7 %). À l’inverse, seulement 34,7 % et 28 % considéraient leurs connaissances suffisantes sur la dysfonction érectile et la transplantation rénale. Enfin, 7,5 % exprimaient le souhait de devenir urologue. La réalisation d’un stage en urologie était associée au sentiment d’avoir acquis les connaissances pour débuter l’internat (p &lt; 0,001) et au souhait d’être urologue (p &lt; 0,001). Conclusion Contre toute attente, l’urologie était considérée comme une discipline médicochirurgicale importante par la moitié des étudiants en fin de DCEM malgré le faible nombre d’items dédiés à l’urologie dans le programme de l’ENC. Un tiers d’entre eux utilisaient le polycopié national du collège d’Urologie pour préparer l’ENC et un quart avait réalisé un stage en urologie