A Preliminary Study for Ant Colony Optimization with a new Reinforcement Strategy

Different Ants Colony Optimization (ACO) algorithms use pheromone information differently in an attempt to improve their relative performance. In this paper, we describe a new systematic reinforcement strategy as a means to improve the pheromone update rules of existing ACO algorithms. We examine the proposed strategy and compare it with other improvement strategies using the well - known Traveling Salesman Problem (TSP). The results indicate that the performance of both the AntSystem (AS) and the Ant Colony System (ACS) algorithms is improved by applying the proposed strategy. We postulate that the proposed strategy allows the ants, in some sense, to both refine the search in promising regions, and escape explored areas of the search space more consistently and effectively than other reinforcement strategies

A shape optimization formulation of weld pool determination

International audienceIn this paper, we propose a shape optimization formulation for a problem modeling a process of welding. We show the existence of an optimal solution. The finite element method is used for the discretization of the problem. The discrete problem is solved by an identification technique using a parameterization of the weld pool by Bézier curves and Genetic algorithms

Delayed bile leak in a patient with grade IV blunt liver trauma: A case report and review of the literature

AbstractIntroductionDelayed bile leak following blunt liver trauma is not common.Presentation of caseWe presented a case report and literature review of delayed bile leak in a young male patient who presented with grade IV blunt liver injury following a motor vehicle collision; he was a restrained driver who hit a fixed object. Physical examination was unremarkable except for revelaed tachycardia, right upper quadrant abdominal tenderness, and open left knee fracture. A diagnosis of grade IV multiple liver lacerations with large hemo-peritoneum was made and urgent exploratory laparotomy was performed. The patient developed a biloma collection post- operatively. He underwent endoscopic retrograde cholangiopancreatography (ERCP) and common bile duct stenting. His recovery was uneventful, and he was discharged home after 1 month.DiscussionThis is a rare case with no intra or extra hepatic biliary radicle injury seen on magnetic resonance cholangiopancreatography (MRCP) and no evidence of leak by ERCP. A review of the literature to highlight the incidence of delayed bile leak revealed only few reported cases.ConclusionOur findings demonstrate the need for prompt diagnosis and treatment of delayed bile leak in blunt liver injuries. When these principles are followed, a successful outcome is possible

Clinical Presentation and Time-Based Mortality in Patients With Chest Injuries Associated With Road Traffic Accidents

Background: Blunt chest trauma (BCT) poses significant morbidity and mortality worldwide. Objectives: We investigated the clinical presentation and outcome of BCT related to road traffic accidents (RTA). Patients and Methods: A retrospective observational analysis for patients who sustained BCT secondary to RTA in terms of motor vehicle crash (MVC) and pedestrian-motor vehicle accidents (PMVA) who were admitted to the trauma center at Hamad general hospital, Doha, Qatar, between 2008 and 2011. Results: Of 5118 traumatic injury cases, 1004 (20%) were found to have BCT secondary to RTA (77% MVC and 23% PMVA). The majority were males (92%), and expatriates (72%). Among MVCs, 84% reported they did not use protective devices. There was a correlation between chest abbreviated injury score (AIS) and injury severity scoring (ISS) (r = 0.35, r2 = 0.12, P < 0.001). Regardless of mechanism of injury (MOI), multivariate analysis showed that the head injury associated with chest AIS and ISS was a predictor of mortality in BCT. Overall mortality was 15%, and the highest rate was observed within the first 24 hours post-trauma. Conclusions: Blunt chest trauma from RTA represents one-fifth of the total trauma admissions in Qatar, with a high overall mortality. Pedestrians are likely to have more severe injuries and higher fatality rates than MVC victims. Specific injury prevention programs focusing on road safety should be implemented to minimize the incidence of such preventable injuries

Oral carriage of candidiasis in patients with oral dental diseases : predisposing factors, species and their antifungal susceptibility patterns

The aim of this study was to evaluate prevalence, frequency and predisposing factors as well as their antifungal susceptibility pattern of oral candidiasis (OC) in patients attending outpatient\u2019s dental clinic with various dental diseases. A total of 150 patients were enrolled in this study aged from 4 to 73 years attended outpatient dental clinic, at Zahra district Tripoli, Libya between May 20017 and May 2018. The purpose of this study was to evaluate the frequency of yeasts in the oral cavity, and to determine the main yeast species present, their correlation with various dental problems as well as other predisposing factors and there antifungal susceptibility patterns. One hundred and fifty patients were enrolled in this study. Patients were submitted to an odontological examination for the identification of dental caries and dental plaque, and other dental problems, as well as for yeast culture. Identification of all species was based on standard mycological methods and antifungal susceptibility test was performed by using disk diffusion susceptibility method and several antifungal drugs such as (fluconazole, amphotericin B, ketoconazole, econazole, itraconazole) were used. The frequency oral carriage of yeasts was 64 % (96), with 78% aged from 20 to 60 years old. Caries, plaque, gingivitis periodontitis, and lower teeth are the most dental problem in which, more than 50% harbors candida species in their oral cavity. Diabetes, pregnancy and smoking, is among common predisposing factors. Candida albicans was the most prevalent species (41.7%), C. glabrate (27.1%) and C. dubliniensis (11.5%). Susceptibility test show that Candida albicans was highly resistant to most azole antifungal and Candida dubliniensis was highly resistant to fluocytosine. Other candida species show variable susceptibility to various antifungal drugs. Aim of study: The purpose of this study was to evaluate the frequency of yeasts in the oral cavity, and to determine the main yeast species present, their correlation with various dental problems as well as other predisposing factors and there antifungal susceptibility patterns. One hundred and fifty patients were enrolled in this study. Patients were submitted to an odontological examination for the identification of dental caries and dental plaque, and other dental problems, as well as for yeast culture. Identification of all species was based on standard mycological methods and antifungal susceptibility test was performed by using disk diffusion susceptibility method and several antifungal drugs such as (fluconazole, amphotericin B, ketoconazole, econazole, itraconazole) were used. Material and methods: One hundred and fifty patients were enrolled in this study. Patients were submitted to an odontological examination for the identification of dental caries and dental plaque, and other dental problems, as well as for yeast culture. Identification of all species was based on standard mycological methods and antifungal susceptibility test was performed by using disk diffusion susceptibility method and several antifungal drugs such as (fluconazole, amphotericin B, ketoconazole, econazole, itraconazole) were used. Results: The frequency oral carriage of yeasts was 64 % (96), with 78% aged from 20 to 60 years old. Caries, plaque, gingivitis periodontitis, and lower teeth are the most dental problem in which, more than 50% harbors candida species in their oral cavity. Diabetes, pregnancy and smoking, is among common predisposing factors. Candida albicans was the most prevalent species (41.7%), C. glabrate (27.1%) and C. dubliniensis (11.5%). Susceptibility test show that Candida albicans was highly resistant to most azole antifungal and Candida dubliniensis was highly resistant to fluocytosine. Other candida species show variable susceptibility to various antifungal drugs. Conclusion: This finding indicated a correlation between the presence of caries and other dental diseases with yeasts carriage in the mouth. However, there was no clear cut correlation between yeasts carriage in healthy and health patients

Fundamental niche prediction of the pathogenic yeasts cryptococcus neoformans and cryptococcus gattii in europe

Fundamental niche prediction of Cryptococcus neoformans and Cryptococcus gattii in Europe is an important tool to understand where these pathogenic yeasts have a high probability to survive in the environment and therefore to identify the areas with high risk of infection. In this study, occurrence data for C. neoformans and C. gattii were compared by MaxEnt software with several bioclimatic conditions as well as with soil characteristics and land use. The results showed that C. gattii distribution can be predicted with high probability along the Mediterranean coast. The analysis of variables showed that its distribution is limited by low temperatures during the coldest season, and by heavy precipitations in the driest season. C. neoformans var. grubii is able to colonize the same areas of C. gattii but is more tolerant to cold winter temperatures and summer precipitations. In contrast, the C. neoformans var. neoformans map was completely different. The best conditions for its survival were displayed in sub-continental areas and not along the Mediterranean coasts. In conclusion, we produced for the first time detailed prediction maps of the species and varieties of the C. neoformans and C. gattii species complex in Europe andMediterranean area

Contribution à l'approximation de problème d'identification et décomposition de domaine en élasticité.

This research work developed here concerns a contribution to approximate an identification problem and domain decomposition for elasticity equations. The first work presents an iterative alternating algorithm for solving an inverse problem in linear elasticity. A relaxation procedure is developed in order to increase the rate of convergence of the algorithm and two selection criteria for the variable relaxation factors are provided. The boundary element method is used in order to implement numerically the constructing algorithm. We discuss this implementation, mention the use of Krylov methods to solve the obtained linear algebraic systems of equations and investigate the convergence and the stability when the data is perturbed by noise. In the second work, we discuss a domain decomposition method to solve linear elasticity problems in complicated 2-D geometries. We describe in details algebraic system corresponding to Dirichlet-Neumann and Schwarz methods. The alternating iterative algorithm obtained is numerically implemented using the boundary element method. The stopping and accuracy criteria, and two type of domain are investigated which confirm that the iterative algorithm produces a convergent and accurate numerical solution with respect to the number of iterations. Finally, a non-overlapping domain decomposition method for elasticity equations based on an optimal control formulation is presented. The existence of a solution is proved and the convergence of a subsequence of the approximate solutions to a solution of the continuous problem is shown. The implementation based on lagrangian method is discussed. Finally, numerical results showing the efficiency of our approach and confirming the convergence result are given.Ce travail de recherche que nous avons développé dans ce mémoire porte sur une contribution d'approximation de problème d'identification et décomposition de domaine pour les équations d'élasticité. Le premier axe présente un algorithme alternatif pour résoudre un problème inverse d'identification de données en élasticité linéaire. Une procédure de relaxation est développée afin d'assurer et d'accélerer la convergence de l'algorithme et deux critères de sélection pour le paramètre de relaxations sont discutés. La méthode des éléments frontière est utilisée pour approcher le problème et de mettre en oeuvre numériquement l'algorithme de reconstruction de données. Nous discutons la résolution des systèmes linéaires obtenus en utilisant des méthodfes itératives de type Krylov, nous avons présenté des résultats de la convergence et la stabilité lorsque les données sont perturbées par un bruit. Dans ce deuxième travail, nous nous intéressons à l'application de la méthode de décomposition en sous-domaines à un problème d'élasticité linéaire. L'approximation se fait par les équations intégrales et les éléments de frontières. Nous décrivons les systèmes algébriques issus des méthodes de décomposition avec recouvrement et sans recouvrement. Nous présentons ensuite deux algorithmes. Les résultats numériques illustrent la convergence de ces deux algorithmes vers la solution du problème d'élasticité linéaire dans différents domaines. Enfin, une méthode de décomposition de domaine sans recouvrement pour les équations d'élasticité basée sur une formulation en contrôle optimal est présenté. L'existence d'une solution est démontrée et la convergence d'une suite des solutions approchées à la solution du problème continu est démontrée. Nous avons présenté aussi un algorithme d'optimisation et les résultats numériques démontrent l'efficacité de notre algorithme et confirment le résultat de convergence