Renewal structure and local time for diffusions in random environment

We study a one-dimensional diffusion $X$ in a drifted Brownian potential $W\_\kappa$, with 0\textless{}\kappa\textless{}1, and focus on the behavior of the local times $(\mathcal{L}(t,x),x)$ of $X$ before time t\textgreater{}0.In particular we characterize the limit law of the supremum of the local time, as well as the position of the favorite sites. These limits can be written explicitly from a two dimensional stable L{\'e}vy process. Our analysis is based on the study of an extension of the renewal structure which is deeply involved in the asymptotic behavior of $X$.Comment: 61 page

Management of inflammatory bowel disease in France: a nationwide survey among private gastroenterologists

Introduction : Les données sur la gestion actuelle des patients atteints de maladie inflammatoire chronique intestinale (MICI) sont rares. Matériel et méthodes : Il s’agissait d’une enquête nationale sur internet réalisée auprès de gastro-entérologues libéraux sous forme de questions à choix multiples en Juin 2012. Résultats : 375 patients atteints de MICI ont été inclus : 48 % d’entre eux avaient une rectocolite hémorragique (RCH). Un antécédent d’hospitalisation concernait un tiers des patients atteints de MICI, et un antécédent de chirurgie 40 % des patients atteints de maladies de Crohn (MC). Deux tiers des patients avaient une maladie active le jour de la consultation (l’activité de la maladie était jugée par le médecin sans score). Soixante pour cent des patients atteints de RCH étaient traités par 5-aminosalicylés contre 18,5 % de MC (p<0,001). Parmi les patients traités par anti-TNF, seulement 4,5 % recevaient un traitement concomitant par immunomodulateur. La moitié des patients avaient eu une coloscopie dans l’année. Concernant le dépistage du cancer colorectal, des biopsies étagées et la chromoendoscopie étaient réalisées dans respectivement 75 % et 40 % des cas. Un score endoscopique d’activité n’était utilisé que chez 10 % des patients. Environ un tiers des patients ayant une MICI avait eu une imagerie dans l’année : l’entéro-IRM représentait environ la moitié de ces prescriptions. Le scanner a été prescrit chez 12 % des patients et l’échographie chez seulement 7 %. Conclusion : De nombreux patients ont encore une maladie active à l’ère des biothérapies, et la proportion de patients recevant une association anti-TNF et azathioprine reste faible en médecine libérale. La coloscopie est toujours la référence pour évaluer l’activité des MICI même si l’IRM est de plus en plus pratiquée. La chromoendoscopie et les scores endoscopiques sont encore sous-utilisés.Background: Data on the current management of inflammatory bowel disease (IBD) are scarce. Materials and Methods: This was a web-based nationwide survey consisting of multiple-choice questions among private gastroenterologists in France in June 2012. Results: 375 IBD patients were analyzed: 48% had ulcerative colitis (UC). History of hospitalization concerned one third of IBD patients, and history of surgery 40% of Crohn’s disease patients (CD). Two thirds of IBD patients had active disease (disease activity was judged by the physician without using a validated tool or a score). The proportion of patients treated with anti-TNF therapy was significantly lower in UC (18.9%) than in CD (38.9 %; p<0.0001). Sixty per cent of UC patients were treated with 5-aminosalicylates as compared with 18.5% of in CD (p<0.0001). Among anti-TNF treated patients, only 4.5% were receiving concomitant immunomodulator. Half of IBD patients had a colonoscopy within the past year. Regarding colorectal cancer screening, random biopsies and chromoendoscopy were performed in 75% and 40% of cases, respectively. An endoscopic score was used for only 10% of IBD patients. About one third of IBD patients had imaging studies within the past year, MRI enterography representing about half of them. Abdominal CT was prescribed for 12% of IBD patients and abdominal ultrasound for only 7% of them. Conclusions: Many patients still have active disease in the biologics era despite an increasing use of immunosuppressive therapy, and the number of patients receiving combination therapy is low in private practice. Colonoscopy remains the gold standard to assess IBD even though MRI is increasingly used in these patients. Chromoendoscopy and endoscopy scores are not often used

SMC 5/6 acts jointly with Fanconi anemia factors to support DNA repair and genome stability

SMC5/6 function in genome integrity remains elusive. Here, we show that SMC5 dysfunction in avian DT40 B cells causes mitotic delay and hypersensitivity toward DNA intra- and inter-strand crosslinkers (ICLs), with smc5 mutants being epistatic to FANCC and FANCM mutations affecting the Fanconi anemia (FA) pathway. Mutations in the checkpoint clamp loader RAD17 and the DNA helicase DDX11, acting in an FA-like pathway, do not aggravate the damage sensitivity caused by SMC5 dysfunction in DT40 cells. SMC5/6 knockdown in HeLa cells causes MMC sensitivity, increases nuclear bridges, micronuclei, and mitotic catastrophes in a manner similar and non-additive to FANCD2 knockdown. In both DT40 and HeLa systems, SMC5/6 deficiency does not affect FANCD2 ubiquitylation and, unlike FANCD2 depletion, RAD51 focus formation. SMC5/6 components further physically interact with FANCD2-I in human cells. Altogether, our data suggest that SMC5/6 functions jointly with the FA pathway to support genome integrity and DNA repair and may be implicated in FA or FA-related human disorders

Régime sans gluten

Tuberculosis, despite its prevention, remains an endemic affection in Morocco. Although rare, pseudo surgical forms and especially peritonitis are mainly due to delayed diagnosis. We report the case of a 30-year-old woman, admitted for peritonitis. The diagnosis of tuberculous peritonitis was established during surgery with macroscopic observation of granulations, and confirmed after biopsy specimens by identification of a giant lymph node cell granuloma with caseous necrosis. Outcome was favorable after appropriate antibiotic therapy. This observation emphasizes the fact that peritonitis, although a rare complication of peritoneal tuberculosis, poses problems of positive and differential diagnosis. Even if treatment is based on antituberculous quadritherapy, surgery is sometimes necessary and should be decided in due time

Risques et adaptation nutritionnelle en cancérologie

This article starts with a presentation of Caycedian Sophrology. We then evaluate its impact on stress reduction through a questionnaire on a students’ population. It appears that stress level increases between the two sessions in the control group while it decreases in the experimental group

Localization and number of visited valleys for a transient diffusion in random environment

59 pages, 2 figuresInternational audienceWe consider a transient diffusion in a $(-\kappa/2)$-drifted Brownian potential $W_{\kappa}$ with $0<\kappa<1$. We prove its localization at time $t$ in the neighborhood of some random points depending only on the environment, which are the positive $h_t$-minima of the environment, for $h_t$ a bit smaller than $\log t$. We also prove an Aging phenomenon for the diffusion, a renewal theorem for the hitting time of the farthest visited valley, and provide a central limit theorem for the number of valleys visited up to time $t$.The proof relies on a decomposition of the trajectory of $W_{\kappa}$ in the neighborhood of $h_t$-minima, with the help of results of A. Faggionato, and on a precise analysis of exponential functionals of $W_{\kappa}$ and of $W_{\kappa}$ Doob-conditioned to stay positive

Ultrasound transmission through monodisperse 2D microfoams

International audienceWhile the acoustic properties of solid foams have been abundantly characterized, sound propagation in liquid foams remains poorly understood. Recent studies have investigated the transmission of ultrasound through three-dimensional polydisperse liquid foams (Pierre et al., 2013, 2014, 2017). However, further progress requires to characterize the acoustic response of better-controlled foam structures. In this work, we study experimentally the transmission of ultrasounds through a single layer of monodisperse bubbles generated by microfluidics techniques. In such a material, we show that the sound velocity is only sensitive to the gas phase. Nevertheless, the structure of the liquid network has to be taken into account through a transfer parameter analogous to the one in a layer of porous material. Finally, we observe that the attenuation cannot be explained by thermal dissipation alone, but is compatible with viscous dissipation in the gas pores of the monolayer