Analysis of generalized negative binomial distributions attached to hyperbolic Landau levels

To each hyperbolic Landau level of the Poincar\'e disc is attached a generalized negative binomial distribution. In this paper, we compute the moment generating function of this distribution and supply its decomposition as a perturbation of the negative binomial distribution by a finitely-supported measure. Using the Mandel parameter, we also discuss the nonclassical nature of the associated coherent states. Next, we determine the L\'evy-Kintchine decomposition its characteristic function when the latter does not vanish and deduce that it is quasi-infinitely divisible except for the lowest hyperbolic Landau level corresponding to the negative binomial distribution. By considering the total variation of the obtained quasi-L\'evy measure, we introduce a new infinitely-divisible distribution for which we derive the characteristic function

Numerical identification of initial temperatures in heat equation with dynamic boundary conditions

We investigate the inverse problem of numerically identifying unknown initial temperatures in a heat equation with dynamic boundary conditions whenever some overdetermination data is provided after a final time. This is a backward parabolic problem which is severely ill-posed. As a first step, the problem is reformulated as an optimization problem with an associated cost functional. Using the weak solution approach, an explicit formula for the Fr\'echet gradient of the cost functional is derived from the corresponding sensitivity and adjoint problems. Then the Lipschitz continuity of the gradient is proved. Next, further spectral properties of the input-output operator are established. Finally, the numerical results for noisy measured data are performed using the regularization framework and the conjugate gradient method. We consider both one- and two-dimensional numerical experiments using finite difference discretization to illustrate the efficiency of the designed algorithm. Aside from dealing with a time derivative on the boundary, the presence of a boundary diffusion makes the analysis more complicated. This issue is handled in the 2-D case by considering the polar coordinate system. The presented method implies fast numerical results

Numerical impulse controllability for parabolic equations by a penalized HUM approach

This work presents a comparative study to numerically compute impulse approximate controls for parabolic equations with various boundary conditions. Theoretical controllability results have been recently investigated using a logarithmic convexity estimate at a single time based on a Carleman commutator approach. We propose a numerical algorithm for computing the impulse controls with minimal $L^2$-norms by adapting a penalized Hilbert Uniqueness Method (HUM) combined with a Conjugate Gradient (CG) method. We consider static boundary conditions (Dirichlet and Neumann) and dynamic boundary conditions. Some numerical experiments based on our developed algorithm are given to validate and compare the theoretical impulse controllability results

Lipschitz stability for an inverse source problem of the wave equation with kinetic boundary conditions

In this paper, we present a refined approach to establish a global Lipschitz stability for an inverse source problem concerning the determination of forcing terms in the wave equation with mixed boundary conditions. It consists of boundary conditions incorporating a dynamic boundary condition and Dirichlet boundary condition on disjoint subsets of the boundary. The primary contribution of this article is the rigorous derivation of a sharp Carleman estimate for the wave system with a dynamic boundary condition. In particular, our findings complete and drastically improve the earlier results established by Gal and Tebou [SIAM J. Control Optim., 55 (2017), 324-364]. This is achieved by using a different weight function to overcome some relevant difficulties. As for the stability proof, we extend to dynamic boundary conditions a recent argument avoiding cut-off functions. Finally, we also show that our developed Carleman estimate yields a sharp boundary controllability result

Antimicrobial susceptibility of urinary Klebsiella pneumoniae and the emergence of carbapenem-resistant strains: A retrospective study from a university hospital in Morocco, North Africa

Introduction: Urinary tract infections (UTIs) due to multi-drug resistant Klebsiella pneumoniae (K. pneumoniae) strains are increasing worldwide and have become a major public health problem.Objectives: The aim of this study was to determine the current and local antimicrobial susceptibility of urinary K. pneumoniae isolated from inpatients and outpatients in a university hospital.Subjects and methods: A retrospective study was carried out, covering a 3-year period from January 2010 to December 2012. It focused on all the K. pneumoniae strains isolated from the urine samples analyzed at the microbiology laboratory of the Avicenne Teaching Hospital, Marrakech, Morocco, North Africa.Results: K. pneumoniae represented 22% of all the urinary Enterobacteriaceae isolated during the study period. The bacterial resistance rates of K. pneumoniae isolates not producing extended spectrum - lactamase (ESBL) were as follows: trimethoprim sulfamethoxazole “T/S” (61%), amoxicillin/clavulanic acid (51%), ciprofloxacin (32%), gentamicin (21%) and amikacin (11%). ESBL producing K. pneumoniae strains accounted for 25.5% of all the urinary K. pneumoniae isolates and showed resistance to T/S (89%), gentamicin (89%), ciprofloxacin (84%) and amikacin (50%). For the first time in our region, we also noted the emergence of carbapenem-resistant strains that accounted for 7% of all the urinary ESBL-producing K. pneumoniae isolates.Keywords: Urinary; Klebsiella pneumoniae; Antimicrobial resistanc

Distribution of the different species of the Pseudallescheria boydii/Scedosporium apiospermum complex in French patients with cystic fibrosis

As various new sibling species within the Pseudallescheria boydii/Scedosporium apiospermum complex have been described recently with differences in their susceptibility to antifungals, this study was conducted in order to determine their respective frequency in cystic fibrosis. Results indicated that P. boydii largely predominated (62%), followed by S. apiospermum (24%), Scedosporium aurantiacum (10%) and Pseudallescheria minutispora (4%). Scedosporium dehoogii was not recovered in this study. The multiple correspondence factor analysis highlighted geographical discrepancies within species distribution: P. boydii was rarely encountered in Northern France, while S. apiospermum was less represented in the west of the country. Additionally, we demonstrated that all species encountered in the cystic fibrosis context were capable to chronically colonize the respiratory tract of patients. Molecular typing of a large set of environmental and clinical isolates should be conducted to delineate the epidemiology of each sibling species in the complex

Rôle du laboratoire dans le diagnostic virologique de la grippe pandémique A(H1N1)v

La nouvelle grippe pandémique, apparue au mois d’avril 2009 au Mexique est encore appelée grippe porcine. Elle est due à un nouveau virus Influenza A(H1N1)v, totalement inédit, jamais identifié auparavant dans aucune espèce et résulte de réassortiments génétiques complexes. Le rôle du laboratoire est fondamental pour le diagnostic virologique de cette grippe émergente. Il permet d’apporter la certitude du diagnostic chez des patients dont le contexte clinico-épidémiologique est évocateur d’une infection par le virus A(H1N)v. La confirmation virologique d’un cas d’infection due à ce virus est apportée par la positivité des tests de laboratoire suivants: RT-PCR et/ou culture virale et/ou multiplication par quatre du taux des anticorps neutralisants spécifiques dirigés contre le virus A(H1N1)v sur une paire de sérums prélevés à deux semaines d'intervalle. La RT-PCR en temps réel, représente à l’heure actuelle un outil de choix en raison de sa rapidité, sensibilité et spécificité. Les tests immunologiques de diagnostic rapide (TDR) permettent de détecter la présence des antigènes de la nucléoprotéine des virus grippaux saisonniers de type A et B. L’évaluation de ces tests a montré, dans le contexte pandémique actuel, une faible sensibilité ne leur conférant pas une valeur prédictive négative compatible avec une utilisation généralisée. Leurs résultats doivent être interprétés avec prudence et malgré leur bonne valeur prédictive positive, ils ne permettent qu’un diagnostic de présomption, une confirmation par RT-PCR en temps réel sera conduite chaque fois que cela est nécessaire

Identification des réservoirs du complexe Scedosporium apiospermum au Maroc

Communications libresNational audienc

Molecular characterization of extended spectrum β-lactamase-producing Escherichia coli in a university hospital in Morocco, North Africa

Introduction: β-Lactams are among the most widely prescribed antibiotics in human medicine. However, because of their massive and usually inappropriate use, resistance to these drugs has increased markedly, especially due to extended-spectrum β-lactamase (ESBL) production.Objectives: The aims of this study were to determine the prevalence of urinary Escherichia coli strains isolated from urine samples taken from patients diagnosed with urinary tract infections (UTIs), to evaluate their current antimicrobial susceptibility pattern and to look for blaSHV, blaTEM and blaCTX-M genes in these multi-drug resistant isolates.Subject and methods: A retrospective survey was made over 3 years from 2010 to 2012. It included all uropathogenic E. coli strains isolated from urine samples taken from consulting and hospitalized patients in the Avicenne Teaching Hospital in Marrakech, Morocco.Results: E. coli was the etiologic agent in 63% of reported UTIs due to Enterobacteriacae. In all, the prevalence of ESBL-producing E. coli reached 6% of all urinary Enterobacteriaceae isolates in 2012. The bacterial resistance rates of ESBL-producing E. coli isolates were as follows: amoxicillin/clavulanic acid (100%), trimethoprim/sulfamethoxazole (76%), gentamicin (66%), ciprofloxacin (82%) and amikacin (56%). None of these strains was resistant to carbapenems. The ESBL production patterns observed included single production of CTX-M (70%), SHV (12%) and TEM (0%). Some ESBL-producing E. coli isolates produced combinations of 2 ESBLs belonging to different groups: CTX-M+SHV (12%) and CTX-M+TEM (6%).Conclusion: The results of this work report, for the first time in the Marrakech region, the ESBL production pattern with CTX-M being most common among the ESBL-producing urinary E. coli. Moreover, a major finding is the production of multiple ESBL types by some urinary E. coli isolates.KEYWORDS Urinary; Extended-spectrum β-lactamase (ESBL); E. coli; Antibiotics; Resistanc