Thermodynamic Properties of the 2N-Piece Relativistic String

The thermodynamic free energy F(\beta) is calculated for a gas consisting of the transverse oscillations of a piecewise uniform bosonic string. The string consists of 2N parts of equal length, of alternating type I and type II material, and is relativistic in the sense that the velocity of sound everywhere equals the velocity of light. The present paper is a continuation of two earlier papers, one dealing with the Casimir energy of a 2N--piece string [I. Brevik and R. Sollie (1997)], and another dealing with the thermodynamic properties of a string divided into two (unequal) parts [I. Brevik, A. A. Bytsenko and H. B. Nielsen (1998)]. Making use of the Meinardus theorem we calculate the asymptotics of the level state density, and show that the critical temperatures in the individual parts are equal, for arbitrary spacetime dimension D. If D=26, we find \beta= (2/N)\sqrt{2\pi /T_{II}}, T_{II} being the tension in part II. Thermodynamic interactions of parts related to high genus g is also considered.Comment: 15 pages, LaTeX, 2 figures. Discussion in section 8 expande

Etude rhéologique et thermique d'une boucle de réfrigération secondaire par coulis d'hydrates

14e édition du congrès de la Société française du génie des procédés, Lyon, FRA, 08-/10/2013 - 10/10/2013International audienceLes fluides réfrigérants classiques sont néfastes pour l'environnement en raison de leur potentiel de réchauffement global (GWP), c'est pourquoi leur utilisation doit être réduite. L'une des solutions est d'employer des fluides frigoporteurs diphasiques, comme les coulis d'hydrates, pour transporter le froid. Le travail réalisé a pour objectif d'étudier les propriétés rhéologiques et thermiques des coulis de CO2. Le dispositif expérimental est constitué d'une boucle pilote permettant la circulation des fluides. Les hydrates sont formés par refroidissement à des températures de l'ordre de 275 K et des pressions allant jusqu'à 3 MPa. Les coefficients d'échange thermique locaux et moyens du coulis ont également été évalués par l'utilisation d'un tube chauffant. La rhéologie a montré que le coulis présentait un comportement de type rhéofluidifiant pour des fractions d'hydrates en volume allant jusqu'à 22 %. L'étude thermique a quant à elle montré que le coulis présentait des coefficients d'échange locaux de l'ordre de 2900 W.m-2.K-1 pour une fraction en hydrates de 19 %, ce qui est supérieur à l'eau et légèrement plus élevé que le coulis de glace. Ainsi, ces résultats permettent de mettre en évidence les bonnes capacités du coulis d'hydrates à stocker, à véhiculer et à restituer l'énergie emmagasinée

A Very High-Order Accurate Staggered Finite Volume Scheme for the Stationary Incompressible Navier–Stokes and Euler Equations on Unstructured Meshes

International audienceWe propose a sixth-order staggered finite volume scheme based on polynomial reconstructions to achieve high accurate numerical solutions for the incompressible Navier-Stokes and Euler equations. The scheme is equipped with a fixed-point algorithm with solution relaxation to speed-up the convergence and reduce the computation time. Numerical tests are provided to assess the effectiveness of the method to achieve up to sixth-order con-2 Ricardo Costa et al. vergence rates. Simulations for the benchmark lid-driven cavity problem are also provided to highlight the benefit of the proposed high-order scheme

Finite volume scheme based on cell-vertex reconstructions for anisotropic diffusion problems with discontinuous coefficients

We propose a new second-order finite volume scheme for non-homogeneous and anisotropic diffusion problems based on cell to vertex reconstructions involving minimization of functionals to provide the coefficients of the cell to vertex mapping. The method handles complex situations such as large preconditioning number diffusion matrices and very distorted meshes. Numerical examples are provided to show the effectiveness of the method

Second-order finite volume with hydrostatic reconstruction for tsunami simulation

Tsunami modeling commonly accepts the shallow water system as governing equations where the major difficulty is the correct treatment of the nonconservative term due to bathymetry variations. The finite volume method for solving the shallow water equations with such source terms has received great attention in the two last decades. The built-in conservation property, the capacity to correctly treat discontinuities, and the ability to handle complex bathymetry configurations preserving some steady state configurations (well-balanced scheme) make the method very efficient. Nevertheless, it is still a challenge to build an efficient numerical scheme, with very few numerical artifacts (e.g., small numerical diffusion, correct propagation of the discontinuities, accuracy, and robustness), to be used in an operational environment, and that is able to better capture the dynamics of the wet-dry interface and the physical phenomena that occur in the inundation area. In the first part of this paper, we present a new second-order finite volume code. The code is developed for the shallow water equations with a nonconservative term based on the hydrostatic reconstruction technology to achieve a well-balanced scheme and an adequate dry/wet interface treatment. A detailed presentation of the numerical method is given. In the second part of the paper, we highlight the advantages of the new numerical technique. We benchmark the numerical code against analytical, experimental, and field results to assess the robustness and the accuracy of the numerical code. Finally, we use the 28 February 1969 North East Atlantic tsunami to check the performance of the code with real data.Historical data for Cascais and Lagos (1969 Lisbon Tsunami) are available at http://www.dgterritorio.pt/cartografia_e_geodesia/geodesia/redes_geodesicas/rede_maregrafica/. The tagus estuary data (typewriter document) are available at the Dom Luiz Institute library http://idl.ul.pt/node/33. This work is funded by the Portugal-France research agreement, through the research project GEONUM FCT-ANR/MAT-NAN/0122/2012. This research was financed by Portuguese Funds through FCT-Fundacao para a Ciencia e a Tecnologia, within the Project UID/MAT/00013/2013

Terminology for Achilles tendon related disorders

The terminology of Achilles tendon pathology has become inconsistent and confusing throughout the years. For proper research, assessment and treatment, a uniform and clear terminology is necessary. A new terminology is proposed; the definitions hereof encompass the anatomic location, symptoms, clinical findings and histopathology. It comprises the following definitions: Mid-portion Achilles tendinopathy: a clinical syndrome characterized by a combination of pain, swelling and impaired performance. It includes, but is not limited to, the histopathological diagnosis of tendinosis. Achilles paratendinopathy: an acute or chronic inflammation and/or degeneration of the thin membrane around the Achilles tendon. There are clear distinctions between acute paratendinopathy and chronic paratendinopathy, both in symptoms as in histopathology. Insertional Achilles tendinopathy: located at the insertion of the Achilles tendon onto the calcaneus, bone spurs and calcifications in the tendon proper at the insertion site may exist. Retrocalcaneal bursitis: an inflammation of the bursa in the recess between the anterior inferior side of the Achilles tendon and the posterosuperior aspect of the calcaneus (retrocalcaneal recess). Superficial calcaneal bursitis: inflammation of the bursa located between a calcaneal prominence or the Achilles tendon and the skin. Finally, it is suggested that previous terms as Haglund’s disease; Haglund’s syndrome; Haglund’s deformity; pump bump (calcaneus altus; high prow heels; knobbly heels; cucumber heel), are no longer used

Quinine Treatment Selects the pfnhe-1 ms4760-1 Polymorphism in Malian Patients with Falciparum Malaria

Background. The mechanism of Plasmodium falciparum resistance to quinine is not known. In vitro quantitative trait loci mapping suggests involvement of a predicted P. falciparum sodium-hydrogen exchanger (pfnhe-1) on chromosome 13. Methods. We conducted prospective quinine efficacy studies in 2 villages, Kolle and Faladie, Mali. Cases of clinical malaria requiring intravenous therapy were treated with standard doses of quinine and followed for 28 days. Treatment outcomes were classified using modified World Health Organization protocols. Molecular markers of parasite polymorphisms were used to distinguish recrudescent parasites from new infections. The prevalence of pfnhe-1 ms4760-1 among parasites before versus after quinine treatment was determined by direct sequencing. Results. Overall, 163 patients were enrolled and successfully followed. Without molecular correction, the mean adequate clinical and parasitological response (ACPR) was 50.3% (n = 163). After polymerase chain reaction correction to account for new infections, the corrected ACPR was 100%. The prevalence of ms4760-1 increased significantly, from 26.2% (n = 107) before quinine treatment to 46.3% (n = 54) after therapy (P = .01). In a control sulfadoxine-pyrimethamine study, the prevalence of ms4760-1 was similar before and after treatment. Conclusions. This study supports a role for pfnhe-1 in decreased susceptibility of P. falciparum to quinine in the field.Howard Hughes Medical Institute [55005502]; Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health; European and Developing Countries Clinical Trials Partnership [EDCTP IP_07_31060_002]info:eu-repo/semantics/publishedVersio

COMMD1-Mediated Ubiquitination Regulates CFTR Trafficking

The CFTR (cystic fibrosis transmembrane conductance regulator) protein is a large polytopic protein whose biogenesis is inefficient. To better understand the regulation of CFTR processing and trafficking, we conducted a genetic screen that identified COMMD1 as a new CFTR partner. COMMD1 is a protein associated with multiple cellular pathways, including the regulation of hepatic copper excretion, sodium uptake through interaction with ENaC (epithelial sodium channel) and NF-kappaB signaling. In this study, we show that COMMD1 interacts with CFTR in cells expressing both proteins endogenously. This interaction promotes CFTR cell surface expression as assessed by biotinylation experiments in heterologously expressing cells through regulation of CFTR ubiquitination. In summary, our data demonstrate that CFTR is protected from ubiquitination by COMMD1, which sustains CFTR expression at the plasma membrane. Thus, increasing COMMD1 expression may provide an approach to simultaneously inhibit ENaC absorption and enhance CFTR trafficking, two major issues in cystic fibrosis