Non-Gaussian Distributions in Extended Dynamical Systems

We propose a novel mechanism for the origin of non-Gaussian tails in the probability distribution functions (PDFs) of local variables in nonlinear, diffusive, dynamical systems including passive scalars advected by chaotic velocity fields. Intermittent fluctuations on appropriate time scales in the amplitude of the (chaotic) noise can lead to exponential tails. We provide numerical evidence for such behavior in deterministic, discrete-time passive scalar models. Different possibilities for PDFs are also outlined.Comment: 12 pages and 6 figs obtainable from the authors, LaTex file, OSU-preprint-

DomPep—A General Method for Predicting Modular Domain-Mediated Protein-Protein Interactions

Protein-protein interactions (PPIs) are frequently mediated by the binding of a modular domain in one protein to a short, linear peptide motif in its partner. The advent of proteomic methods such as peptide and protein arrays has led to the accumulation of a wealth of interaction data for modular interaction domains. Although several computational programs have been developed to predict modular domain-mediated PPI events, they are often restricted to a given domain type. We describe DomPep, a method that can potentially be used to predict PPIs mediated by any modular domains. DomPep combines proteomic data with sequence information to achieve high accuracy and high coverage in PPI prediction. Proteomic binding data were employed to determine a simple yet novel parameter Ligand-Binding Similarity which, in turn, is used to calibrate Domain Sequence Identity and Position-Weighted-Matrix distance, two parameters that are used in constructing prediction models. Moreover, DomPep can be used to predict PPIs for both domains with experimental binding data and those without. Using the PDZ and SH2 domain families as test cases, we show that DomPep can predict PPIs with accuracies superior to existing methods. To evaluate DomPep as a discovery tool, we deployed DomPep to identify interactions mediated by three human PDZ domains. Subsequent in-solution binding assays validated the high accuracy of DomPep in predicting authentic PPIs at the proteome scale. Because DomPep makes use of only interaction data and the primary sequence of a domain, it can be readily expanded to include other types of modular domains

Momentum and Buoyancy Repartition in Turbulent Mixed Convection

Turbulent mixed convection is a common phenomenon in applications such as heat exchangers and climatisation in transport vehicles and buildings and was often studied in the past. Metais and Eckert [6] experimentally analyse the heat transport in a vertical pipe heated from the outside. The suppression of turbulence in vertical pipes is analysed by Bae et al. [1] by means of direct numerical simulation (DNS). Mixed convection in a vertical channel is studied in DNS by Kasagi and Nishimura [4], who report profiles of one-point statistics and budgets of the turbulent kinetic energy. They also compare asymmetrically heated turbulent channel flow with channel flow subjected to uniform wall mass injection and suction, as well as with liquid metal channel flow under the influence of a transversal magnetic field. All three flow types exhibit similar effects regarding the suppression and enhancement of turbulence near the walls and Kasagi and Nishimura state that the buoyancy does not affect the velocity fluctuations directly. In a more recent work, He, He and Seddighi [3] study the effects of generic body forces on vertical pipe flow and relate the relaminarization to a lowering of the apparent friction velocity. Wall-normal profiles of the mean streamwise velocity and the turbulent kinetic energy are presented in this paper for different Grashof numbers and demonstrate the buoyancy-induced flow asymmetry. Furthermore, budgets of the Reynolds stress tensor are analysed with regard to the repartition of turbulent stresses between the velocity components. Finally, the heat transport characteristics of the flow are examined with the help of a quadrant analysis of the Reynolds shear stress and the turbulent heat fluxes in order to understand how the coherent structures transport heat

Surgical-site infections and surgery of the salivary glands

SummaryObjectivesTo determine the surgical-site infection (SSI) incidence rate targeted on salivary gland surgery over a 2-year period (from January 2007 to December 2008). Then identify any risk factors associated with SSI in all the patients operated with no antibiotic prophylaxis in accordance with French Anesthesiology Society guidelines.Population and methodsNinety-three patients were operated during the standard SSI surveillance period. A case-control (one case for five controls) study was then conducted aiming to identify risk factors.ResultsThe SSI incidence rate was 9.7%. The case-control study failed to identify any relevant risk factor with univariate analysis.ConclusionAs no risk factors could be identified, we suggest that surgical antibioprophylaxis could be relevant in salivary glands surgery and should be evaluated in this setting

Experimental investigation of the visco-plastic mechanical properties of a Sn-based solder alloy for material modelling in Finite Element calculations of automotive electronics

Here, we present an advanced experimental procedure for determining the properties of a SnAg3.5 solder alloy in the strain range of primary creep under cyclic load and isothermal conditions. The challenge in this experiment is the accurate high-resolution measurement of sample elongation used for a closed-loop control, as well as avoiding the influence of sensor and specimen clamping. We realized reproducible strain rate control within a total specimen elongation of 60 μm. The tensile-compression experiment comprises strain rate variation for three strain amplitudes with integrated relaxation stages followed by a measurement of cyclic fatigue. The strain rate at every strain stage was varied in the range of 1E-3 to 1E-6 per second. At the end of every strain stage a time-limited relaxation experiment is performed, where the specimen's length is kept constant, while the stress evolution is recorded. Finally, the specimen is subjected to cyclic fatigue until a drop of 50 % of the initial materials strength is reached. The total procedure is performed in a temperature range from -40 to 150 °C. We prove the capability of common creep models to map the observed cyclic stress-strain hysteresis as well as stress dependency on strain rate. The results reveal substantial limitations of common stationary creep models and strongly suggest the application of advanced visco-plastic material models for an accurate description of the solder alloy properties. The experimental data presented can be used for the calibration of unified visco-plastic constitutive models initially proposed by Chaboché et al. and further extended during the past two decades

Description of the thermo-mechanical properties of a Sn-based solder alloy by a unified viscoplastic material model for finite element calculations

Automotive electronic devices are exposed to substantially harsher thermo-mechanical loads compared to commercial consumer electronic products. As a consequence, solder joints carrying out the electrical interconnection between the components undergo deformation and degradation under thermal cycling, which can determine the lifetime of the electronic assembly in long term operation. In the past decade, lifetime prediction methods for solder joints based on finite element (FE) simulations are increasingly employed in the process of product design. However, constitutive FE models for solder alloys capable of describing their mechanical behavior at the relevant conditions of automotive applications are still not widely established. Here, we employ a unified viscoplastic material model initially proposed by Chaboche et al. in order to address the mechanical properties of an as-casted Sn-based solder alloy under a cyclic mechanical load. Extensive experimental investigations at temperatures from -40°C up to +150°C reveal a complex nonlinear interplay between hardening, recovery and thermally activated inelastic deformation processes in the material studied. We identified the necessary constitutive model terms and performed parameter calibration according to their specific functionality. A very good agreement between the numerical calculations and experimental data is achieved, which renders the constitutive model used a very promising approach for a wide use in FE simulations of lead-free solder alloys

Correlation of sedimentary events during the Latest Cenomanian from the Basque Basin to the Castilian Ramp (Northern Spain)

Sedimentologic, biostratigraphic and geochemical analyses of the Late Cenomanian - Early Turonian series of the deep Basque Basin and of the Navarre-Cantabrian distal Ramp and Castilian proximal Ramp, allow: V to correlate sedimentary events such as the sedimentation of thin layers of organic matter-bearing laminated black shales in the Basque Basin and as the formation of glauconitic-pyritic bioturbated hardgrounds on the Navarre-Cantabrian and Castilian Ramps, 2) to date these events from the Archaeocretacea Zone, 3) to interpret them as evidence of anoxia in the basin and hypoxia on the ramps, and as results of major marine deepening and transgressionEstudios sedimentológicos, bioestratigráficos y geoquímicos de series de edad Cenomanense superior - Turonense inferior de la Cuenca profunda Vasca, de la Rampa distal Navarro-Cantábrica y de la Rampa somera Castellana han permitido: V correlacionar la deposición de arcillas negras laminadas (black shales) en la Cuenca Vasca con la formación de superficies endurecidas (hardgrounds) glauconíticas en las Rampas Navarro-Cantábrica y Castellana, 2) situar estos eventos en la Zona de Archaeocretacea, 3) interpretar dichos depósitos como indicadores de anoxia en la cuenca profunda y de hipoxia sobre las rampas, resultado de una profundi'¿ación y transgresión marina mayo

Prothèse de mémoire fondée sur une ontologie et des interfaces tactiles pour pallier la dégénérescence mnésique

ISSN 1760-5342International audienc