Superfluid Flow Past an Array of Scatterers

We consider a model of nonlinear superfluid flow past a periodic array of point-like scatterers in one dimension. An application of this model is the determination of the critical current of a Josephson array in a regime appropriate to a Ginzburg-Landau formulation. Here, the array consists of short normal-metal regions, in the presence of a Hartree electron-electron interaction, and embedded within a one-dimensional superconducting wire near its critical temperature, $Tc$. We predict the critical current to depend linearly as $A (Tc-T)$, while the coefficient $A$ depends sensitively on the sizes of the superconducting and normal-metal regions and the strength and sign of the Hartree interaction. In the case of an attractive interaction, we find a further feature: the critical current vanishes linearly at some temperature $T*$ less than $Tc$, as well as at $Tc$ itself. We rule out a simple explanation for the zero value of the critical current, at this temperature $T*$, in terms of order parameter fluctuations at low frequencies.Comment: 23 pages, REVTEX, six eps-figures included; submitted to PR

Thermodynamic anomaly of the free damped quantum particle: the bath perspective

A possible definition of the specific heat of open quantum systems is based on the reduced partition function of the system. For a free damped quantum particle, it has been found that under certain conditions, this specific heat can become negative at low temperatures. In contrast to the conventional approaches focusing on the system degree of freedom, here we concentrate on the changes induced in the environment when the system is coupled to it. Our analysis is carried out for an Ohmic environment consisting of harmonic oscillators and allows to identify the mechanism by which the specific heat becomes negative. Furthermore, the formal condition for the occurrence of a negative specific heat is given a physical interpretation in terms of the total mass of bath oscillators and the system mass.Comment: 7 pages, 1 figure, final version after one round of refereein

The \u27Pull\u27 Technique for Removal of Peritoneal Dialysis Catheters: A Call for Re-Evaluation of Practice Standards

Background The most commonly used peritoneal dialysis (PD) catheters have silicon tubing with attached Dacron cuffs. The current standard of care for PD catheter removal is by complete surgical dissection, withdrawing both the tubing and the cuffs. The intention is to avoid infection of any residual part of the catheter. We retrospectively analyzed our results with the alternative ‘pull’ technique, by which the silicon tube is pulled out, leaving the Dacron cuffs within the abdominal wall. This technique never gained popularity due to concern that the retained cuffs would get infected. Methods We reviewed our experience from an 18-month period, between January 2014 and June 2015. There were 46 catheter removals in 40 patients. All the catheters were of the double-cuffed coiled Tenckhoff type (Covidien, Dublin, Ireland). Results Of the 46 catheter removals by the ‘pull’ technique, there was only 1 case of retained cuff infection. Conclusions The ‘pull’ technique is a safe method for Tenckhoff catheter removal with low risk of infection. We strongly recommend it as the procedure of choice

Profil clinique et thérapeutique des complications de la circoncision sur la dernière décennie

L’objectif de l’étude était de rapporter le profil clinique et thérapeutique des complications de la circoncision sur la dernière décennie. Il s’agissait d’une étude observationnelle rétrospective et descriptive menée entre le 1er janvier 2006 et le 31 décembre 2016 répertoriant les complications de la circoncision reçues dans notre service. Les paramètressuivants ont été étudiés: l’âge des patients, la qualification de l’opérateur, le lieu de circoncision, le délai de consultation, les motifs de consultation, les types de complications et leurs traitements, les suites thérapeutiques avec comme critères d’appréciation desrésultats: la qualité de la miction et l’aspect esthétique de la verge. Au total 44 complications de la circoncision ont été recensées durant la période d’étude. L’âge moyen au moment de la circoncision était de 6,01 ± 4,7 ans et au moment de la consultation, il était de 11,3 ± 8,7 ans. Le délai moyen de consultation était de 5,1 ± 6,9 ans. Seuls 2 patients ont consulté dans les délais d’urgence (<6 heures). Le personnel paramédical était responsable de la majorité des complications (59,1% des patients). La fistule urétro-cutanée (FUC) était la complication la plus fréquente (72,7%). La majorité (n=43) de nos patients a eu un traitement chirurgical. Les résultats globaux étaient satisfaisants pour 88,6% des patients pris en charge. Les échecs ne concernaient que les FUC et les amputations du gland et étaient représentés par des récidives de fistules et des nécroses du gland respectivement. Mots clé : circoncision; complications; fistule urétro-cutanée Our purpose is this study was to report clinical and therapeutic aspects of complications of circumcisions over the last ten years. We conducted a descriptive and retrospective study between January 2006 and December 2016, including all cases of complications recorded in the urology unit of Aristide Le Dantec University Teaching Hospital. The following parameters were studied: patient age, operator qualification, the place of circumcision, consultation time, complain, The type of complications and their treatment. Post-operative evolution was appreciated by the quality of micturition and the esthetic result. A total of 44 complications were recorded during the study time. The mean ages were 6.01 years at circumcision, and 11.3 years at consultation. The mean consultation time was 5.1 years, and only 2 patients consulted within the emergency time (less than 6 hours). Fifty-nine point one percent of complications occurred after operation by paramedical personnel. Uretrocutaneous fistula (UCF) was the most frequent complication (72.7%). Almost every patient (43) underwent surgical treatment with a globally satisfactory outcome in 88.6% of cases. Fails like recurrent fistula and glans necrosis were only found respectively in cases of UCF and glans amputation. Key words: circoncision; complications; fistule urétro-cutané