bluuebunny/crossref_metadata_2025 huggingface dataset:
A cap model for soils featuring a smooth transition from partially to fully saturated state
Authors: Gamnitzer Peter , Hofstetter Günter
Published: November 2013

Soils consist of a porous soil skeleton filled by fluids like air and water. The accurate description of their mechanical behaviour requires a coupled solid‐fluid approach. The analysis is based on a set of balance equations, kinematic equations and constitutive equations, the latter including a material model for the soil. Depending on the degree of saturation, the soil behaviour has to be modelled in both, partially and fully saturated state. We present a constitutive model for soils developed from the cap model proposed by Kohler and Hofstetter. The elasto‐plastic model is formulated in terms of two independent stress variables, generalised effective stress σij☆ and matric suction pc. It is applicable to partially and fully saturated state. The yield surface includes a shear failure envelope and a hardening cap surface. Its evolution in terms of matric suction is controlled by the load collapse (LC) yield curve and parameters defining the suction‐dependent intersection of the shear failure envelope with the 1☆‐pc‐plane, where 1☆ = tr(σij☆). Our extension of the model includes an improved LC yield curve to enable a better representation of wetting/drying paths and to allow a smooth transition from partially to fully saturated state. Numerical results for a low to medium plasticity clay are in good agreement with experimental data. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Predicting the onset of delamination in layered fiber‐reinforced composites
Authors: Simon Jaan‐Willem , Stier Bertram , Reese Stefanie
Published: November 2013

In this paper, composite structures are considered which consist of several layers of carbon fiber reinforced plastics (CFRP). For such layered composite structures, delamination constitutes one of the major failure modes and hence predicting its initiation is essential for their design. Evaluating stress‐strength relation based onset criteria requires an accurate representation of the through‐the‐thickness stress distribution, which can be particularly delicate in the case of shell‐like structures. Thus, in this paper, a solid‐shell finite element is utilized, which allows for incorporating a fully three‐dimensional material model, still being suited for application to thin structures. Moreover, locking phenomena are cured by using both the EAS and the ANS concept, and numerical efficiency is ensured through reduced integration. The proposed anisotropic material model accounts for the material's micro‐structure by using the concept of structural tensors. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Heat Transfer in Rotor/Rotor and Rotor/Stator Cavity: Physics, Correlations and Numerical Modeling
Authors: Kielczewski Kamil , Tuliszka‐Sznitko Ewa
Published: November 2013

The transitional and turbulent flow in the near wall sublayer is now mostly modeled based on the existing knowledge of simple 2D flows. To determine the effect of three dimensionality on the turbulent flow structures and turbulent heat transfer in the near wall areas the authors investigate numerically (SVV) turbulent flow in rotor/stator and rotor/rotor flows (with and without axial throughflow). These simple model flows contain most of the phenomena that are needed to understand more complex, 3D transitional and turbulent flows. Attention is focused on the turbulent characteristics which should have more universal character. To stabilize calculations for high Reynolds numbers (up to Re=800 000) the SVV operator is introduced into the Navier‐Stokes and energy equations solver for cylindrical coordinate system without using complex numbers. Code optimization and parallelization have speeded up computations 20 times. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nonlinear Homogenization of Microstructures in Steel with Temperature‐Controlled Phase Transformation
Authors: Neumann Rudolf , Böhlke Thomas
Published: November 2013

For the description of the phase transformation effect TRIP (transformation induced plasticity), a thermo‐micro‐mechanical model is introduced. The scale transition is realized by a Hashin‐Shtrikman type homogenization scheme. The macroscopical behavior is purely based on micro‐mechanical, thermo‐mechanical constitutive models. The model takes into account the thermal strains arising during cooling, and the Greenwood‐Johnson effect. The Greenwood‐Johnson effect describes the TRIP strain developing during the growth of a product phase in the parent phase. The TRIP strain is determined by a micromechanical model gained by an extended Leblond ansatz. For the diffusion driven phase transformation, the JMAK model is incorporated into the homogenization scheme. The diffusionless transformation is described by a rate law of Koistinen‐Marburger type. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Some experimental results on flow in a diverging 2D channel
Authors: Antoš Pavel , Hladík Ondřej , Jonáš Pavel , Uruba Václav
Published: November 2013

The effect of the free stream turbulence (FST) on the essential flow characteristics was investigated in the diverging 2D channel. The diverging channel was modelled in the closed type working section by fastening a displacement body above the flat plate that is parallel with the wind‐tunnel axis. The angle of the channel expansion 11 degree induced the pressure gradient parameter $K = \nu (dU_0/dx)/U_0^2 \approx 0.16 \div -0.28$ with the flow velocity U0 30 m/s at the start of expansion, x = 0. The height of the channel is 0.15 m at x = 0. FST was either natural 0.3 percent or amplified by turbulence generating grids/screens with turbulence levels up to 5 percent. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical Simulation of the Ising Surfaces of the Cylinder and Profile
Authors: Alekseyenko Sergey
Published: November 2013

The basic models and research methods of airfoil icing processes, meteorological parameters, types of clouds, types of ice and their influence on aerodynamic performance are analyzed. For description of impinging water droplets on the surface are used: model of interpenetrating mediums, trajectory model and homogeneous model. Computational procedures of in flight ice accretion are considered. The results of numerical simulation of an ice growing on the cylinder and profile streamlined with two‐phase, viscous, compressible stream, taking into account the interaction of both carrier and liquid phases, the form of existence of moisture on a surface, the change of streamline body geometry and the influence of this change towards external stream are presented. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A New Method for the Assessment of Noise Pollution in Urban Agglomerations
Authors: Arghir Mariana , Macovescu Sorin Constantin
Published: November 2013

This work introduces a new method for the assessment of sound pollution in urban agglomeration. The method is based on fuzzy technique, which is a not used method until at this time for the pollution evaluation, but it will prove to be particularly useful and competitiveness. Starting from the classics design of the crowd and element of a crowd, shall be determined characteristics called degrees of belonging. The work presents the theoretical appropriateness for the application of fuzzy technique, the steps necessary to apply it, the program for the application of this technique, but also the computerized results obtained by application of the new methods, for the assessment of sound pollution by fuzzy technique. Concrete Implementation of a study from municipal area, with the implementation of the evaluation system based on fuzzy crowd is a rapid method, non‐invasive, and has been obtained from the indicator of the impact on an intense inhabited road and powerful intense polluted from the movement of motor vehicles. Results of the study obtained from the application of technique fuzzy, compared with the measurement results in the same places, have proved viable and thus fuzzy technique becomes a useful tool, quick and non ‐destructive test for the assessment noise pollution in urban agglomerations. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Model Identification for Flow Simulations in Geothermal Reservoirs: Towards Optimally Drilling Boreholes
Authors: Padalkina Kateryna , Bücker H. Martin , Herty Michael , Rath Volker , Seidler Ralf
Published: November 2013

In geothermal reservoir engineering, one is interested in determining the location of boreholes such that measurements taken therein, say temperature, will allow the estimation of unknown parameters such as porosity and permeability. We formulate such a particular borehole location problem and find its solution by techniques from optimal experimental design. More precisely, we minimize the D‐optimality criterion to find an optimal location of a single borehole to estimate hydraulic permeability from temperature measurements in two boreholes. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Linearized Elasticity as Γ‐Limit of Finite Elasticity in the Case of Cracks
Authors: Gussmann Pascal
Published: November 2013

The small‐deformation limit of finite elasticity is considered in presence of a fixed crack. The rescaled finite energies with the constraint of global injectivity are shown to Γ‐converge to the linearized elastic energy with a local constraint of noninterpenetrability on the crack. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Uniqueness of Integrable Solutions ∇ζ = Gζ, ζ∣Γ = 0 for Integrable Tensor‐Coefficients G and Applications to Elasticity
Authors: Lankeit Johannes , Neff Patrizio , Pauly Dirk
Published: November 2013

Let $\Omega\subset R^N$ be bounded Lipschitz and $\emptyset\neq\Gamma\subset \partial\Omega$ relatively open. We show that the solution to the linear first order system 1:

vanishes if $G \in {\rm L}^1(\Omega;{\rm I\!R}^{(N \times N)\times N})$ and $\zeta \in {\rm W}^{1,1}(\Omega;{\rm I\!R}^N)$, (e.g. $\zeta \in L^2, G \in L^2$). We prove

to be a norm if $P \in {\rm L}^\infty (\Omega;{\rm I\!R}^{3\times 3})$ with ${\rm Curl}\; P \in {\rm L}^p (\Omega;{\rm I\!R}^{3\times 3})$, ${\rm Curl}\; P^{-1} \in {\rm L}^q (\Omega;{\rm I\!R}^{3\times 3})$ for some p, q > 1 with 1/p + 1/q = 1 and ${\rm det}P \geq c^{+} > 0$. We give a new proof for the so called ‘in‐finitesimal rigid displacement lemma’ in curvilinear coordinates: Let $\Phi \in {\rm H}^1(\Omega;{\rm I\!R}^{3}), \Omega \in {\rm I\!R}^{3}$, satisfy ${\rm sym} (\nabla\Phi^{\rm T} \nabla\Psi) = 0$ for some $\Psi \in {\rm W}^{1,\infty} (\Omega;{\rm I\!R}^{3}) \cap {\rm H}^2 (\Omega;{\rm I\!R}^{3})$ with ${\rm det}\nabla\Psi \geq c^{+} > 0$. Then there are $a \in {\rm I\!R}^{3}$ and a constant skew‐symmetric matrix $A \in {\rm so}(3)$, such that $\Phi = A\Psi +a$. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Singular fractional differential equations
Authors: Stojanovic Mirjana
Published: November 2013

Fractional differential equations have received increasing attention during recent years since the behavior of many physical systems can be properly described using the fractional order system theory.

By fractional analog for Duhamel principle we give the existence‐uniqueness result for linear and nonlinear time fractional evolution equations with singularities in corresponding norm in extended Colombeau algebra of generalized functions. In order to find the explicit solutions we use integral representation of the solution obtained via Laplace and Fourier transforms in succession and their inverses. We deal with some nonlinear models with singularities appearing in viscoelasticity and in anomalous processes, extending the results in viscoelasticity, continuum random walk, seismology, continuum mechanics and many other branches of life and science. The main task is finding existence‐uniqueness results like in the case of evolution equations with entire derivatives. By examining the fractional evolution equations it turns out that they lead to till now known results from the evolution equations with entire derivatives in limiting case. They give more, behavior of the solution when order of derivatives are inside the intervals of entire points. In this way we can follow the influence of the operators generated by entire derivative in many fractional time evolution PDEs especially with singular initial data, and non‐Lipschitz's nonlinear term.

Apart from evolution equations we prove also an existence‐uniqueness result for an initial value problem with singularities for linear and nonlinear fractional elliptic equation of Helmholtz type and fractional order α, where 1 < Re(α) ≤ 2, with respect to the one variable from R+. As a framework, we employ also Colombeau algebra of generalized functions containing fractional derivatives and operations among them in order to deal with the fractional equations with singularities. We apply the same techniques to the fractional Laplace and Poisson equation linear and nonlinear ones. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Uncertainty Quantification and Non‐Linear Bayesian Update of PCE Coefficients
Authors: Litvinenko Alexander , Matthies Hermann G.
Published: November 2013

The Bayesian Update is quite vital for uncertainty quantification. With BU we can take into account the given measurements of our physical model and update the a priori probability density function (which is very often far away from the truth) of the uncertain parameter. The standard full BU is based on sampling and sampling is not always acceptable or possible. In addition, it can require a very large number of samples and is expensive. This led to the development of sampling‐free Bayesian updates. We derive it from the variational problem associated with conditional expectation. Whereas the linear BU is a linear function of the prediction mismatch, here we used higher order polynomials. As an example we took the chaotic Lorenz 84 model. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Surf‐Riding Threshold of Ships in Random Seas
Authors: Dostal Leo , Kreuzer Edwin
Published: November 2013

A possible stability failure in ship dynamics is surf‐riding of the ship in waves followed by broaching‐to. In order to exclude broaching one thus seeks to prevent the ship from surf‐riding. We analyze the surf‐riding problem of a ship in random seas as a weakly perturbed Hamiltonian system, where the excitation owing to irregular sea waves is modeled as a Gaussian process. Then, an approximation of the probability of surf‐riding in irregular sea waves is obtained using the stochastic Melnikov's method, by which means transitions from the asymmetric periodic surging motion to the surf‐riding equilibrium are identified. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An Infinite‐Dimensional Semismooth Newton Method for Elasto‐Plastic Contact Problems
Authors: Hintermüller Michael , Rösel Simon
Published: November 2013

A Fenchel dualization scheme for the one‐step time‐discretized elasto‐plastic contact problem with kinematic or isotropic hardening is considered. The associated path is induced by a combined Moreau‐Yosida / Tichonov regularization of the dual problem. The sequence of solutions to the regularized problems is shown to converge strongly to the solution of the original problem. This property relies on the density of the intersection of certain convex sets. The corresponding conditions are worked out and customary regularization approaches are shown to be valid in this context.

It is also argued that without higher regularity assumptions on the data the resulting problems possess Newton differentiable optimality systems in infinite dimensions [2]. Consequently, each regularized subsystem can be solved mesh‐independently at a local superlinear rate of convergence [6]. Numerically the problems are solved using conforming finite elements. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sparse‐Grid Surrogate Models for Uncertainty Analysis
Authors: Walz Nico‐Philipp , Hanss Michael
Published: November 2013

The computation of fuzzy arithmetical solutions of problems involving uncertain, fuzzy‐valued model parameters can be formulated as a nested sequence of optimization problems. In order to reduce the amount of model evaluations, which is often a limiting factor for the applicability of uncertainty analysis if the original model is evaluated, a surrogate‐model approach based on sparse‐grid interpolation is investigated. The optimization process is then performed on the basis of the surrogate representation, leading to a significant improvement with respect to the computation time. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The extended Kalman Filter and the unscented Kalman Filter for Material Parameter Identification with Application in Tunneling
Authors: Nguyen Luan T. , Nestorović Tamara
Published: November 2013

We present in this work the use of the extended Kalman filter (EKF) and unscented Kalman filter (UKF) for identification of constitutive material parameters with application in mechanized tunneling. Although both filters are based on the principle of recursive least squares estimation, one differs from another in terms of where approximation is made. Whereas in the EKF first‐order Taylor series expansion is used to approximate the nonlinear modeling equation, in the UKF approximation of the probability density of the state is made using a small number of well defined points. To validate the methods, we performed parameter identification of the Hardening Soil constitutive model used for describing the soil behavior in an tunnel excavation model. Both methods showed fast and stable convergence of the considered soil parameters ‐ the four parameters of the Hardening Soil model. Although the EKF requires less number of forward calculations of the numerical model, the UKF is favored since it does not require calculation of the derivatives of the observables with respect to the identifying parameters. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Inverse Design of a Displacement Body with a discrete Adjoint Method
Authors: Stapel Waldemar
Published: November 2013

Wind tunnel experiments at German Aerospace Center (DLR) for the analysis of laminar turbulent transition showed that a nearly linearly decreasing pressure distribution at a plate is able to suppress Tollmien‐Schlichting boundary layer instabilities. Nevertheless, this pressure distribution leads to the growth of nonlinear instabilities in cross flow direction. Within up‐ucoming research projects at DLR it is intended to further investigate this cross flow boundary layer instabilities. The experimental setup consists of a flat plate, a displacement body mounted above the plate and an additional supporting wing. The supporting wing prevents flow separations. The displacement body imposes the particular pressure distribution upon the upper side of the plate. However, contour and position of the displacement body is not known by detail. Therefore, the given pressure distribution is to be recreated by an inverse design procedure. The task can be seen as a design optimisation to a given pressure function. To provide a fast evaluation the discrete adjoint method of the TAU‐Code is used. The problem's cost function is regarded as the residual of the current and the target pressure. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A modified adaptive‐order rational Arnoldi method for model order reduction
Authors: Bodendiek André , Bollhöfer Matthias
Published: November 2013

A Greedy‐type expansion point selection for moment‐matching methods in model order reduction mainly depends on the computation of a sequence of reduced order models. Typically, the adaptive‐order rational Arnoldi (AORA) method resembles an efficient way for the computation of a Galerkin projection corresponding to a set of expansion points. We will provide an extension of the AORA method, in order to reuse the orthonormal basis from previous calls of the AORA method. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bernstein Polynomial Collocation Method for Elliptic Boundary Value Problems
Authors: Mirkov Nikola , Rašuo Boško
Published: November 2013

We present a summary of recent developments in application of Bernstein polynomials to solution of elliptic boundary value problems with a pseudospectral method. Solution is approximated using Benstein polynomial interpolant defined at points of the extrema of Chebyshev polynomials i.e. the Chebyshev‐Gauss‐Lobatto (CGL) nodes. This approach brings impovement comparing to the Bernstein interpolation at equidistant nodes we used previously [1]. We show that this approach leads to spectral convergence and accuracy comparable to that of pseudospectral methods with orthogonal polynomials (Chebyshev, Legendre). The algorithm is implemented in open source librarybernstein‐poly, which is available online. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Modification of the Shishkin Discretization Mesh
Authors: Vulanović Relja , Teofanov Ljiljana
Published: November 2013

In this paper we consider a modification of the Shishkin discretization mesh designed for the numerical solution of one‐dimensional linear convection‐diffusion singularly perturbed problems. The modification consists of a slightly different choice of the transition point between the fine and coarse parts of the mesh. This leads to a better layer‐resolving mesh and to an improvement in the accuracy of the computed solution although the convergence order remains the same. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Convergence of a Finite Difference Scheme for a Parabolic Transmission Problem in Disjoint Domains
Authors: Milovanović Zorica
Published: November 2013

In this paper we investigate a parabolic transmission problem in disjoint domains. An a priori estimate for its weak solution in appropriate Sobolev‐like space is proved. The convergence of a finite difference scheme (FDS) approximating this problem is analyzed. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An Efficient Policy Iteration Algorithm for Dynamic Programming Equations
Authors: Alla Alessandro , Falcone Maurizio , Kalise Dante
Published: November 2013

We present a scheme for Hamilton‐Jacobi‐Bellman equations based on a semi‐Lagrangian discretization and an iterative method in the policy space. The scheme exploits the idea that a good initialization of the policy iteration procedure yields a faster numerical convergence to the optimal solution. The scheme features a pre‐processing step with value iterations on a coarse grid. Numerical tests assess the efficient performance of the method. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Model‐Free Stability‐Based Adaptive Control Method for Unknown Nonlinear Systems
Authors: Shen Xi , Söffker Dirk
Published: November 2013

This contribution considers an adaptive control method based on a cognition‐based framework to stabilize unknown nonlinear systems online. This method requires only the system outputs, which are assumed as measurable. The structure of the framework consists of three parts. The first part is based on a dynamic recurrent neural network (DRNN) to be used for local identification, analysis and multi‐step‐ahead prediction of the system. In the second part, a set of given input values will be calculated numerically with a geometrical criterion based on a suitable definition of quadratic stability. In the third part, the most suitable control input value is chosen for the next predefined time interval according to a suitable cost function. The proposed controller is able to gain useful local knowledge and define autonomously suitable local control input according to the stability criterion. Numerical examples using inverted pendulum system and Lorenz system are shown to demonstrate the successful application and performance of the method. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Necessary and sufficient stability condition for arbitrarily switched linear systems from a data‐driven perspective
Authors: Zhang Fan , Söffker Dirk
Published: November 2013

In this paper, the problem of existence of Common Quadratic Lyapunov Function (CQLF) is handled in a data‐driven manner: instead of using mathematical models, a necessary and sufficient condition for existence of CQLF is established by direct use of measured system states. The paper shows that a CQLF exists if the intersection between the positive real space and the convex cone constructed by the data set transformed from the measured states using a suitable orthogonal matrix is not empty. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison of Numerical Simulation Models for Open Loop Flight Simulations in the Human Centrifuge
Authors: Vidakovic Jelena , Lazarevic Mihailo , Kvrgic Vladimir , Dančuo Zorana , Lutovac Maja
Published: November 2013

To achieve predefined Gz load profile in high G training in human centrifuge, it is necessary to determine angular velocity and acceleration of a planetary axis (centrifuge arm). Initial value problem that can not be solved in closed form was obtained. Several discretization methods for calculating angular velocity of centrifuge arm driven by DC servo motor are presented. Simulations are performed for different positive and negative values of Gz onset. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Resolution of the wavefront set via discrete sets
Authors: Johansson Karoline , Pilipović Stevan , Teofanov Nenad , Toft Joachim
Published: November 2013

We introduce discrete wave‐front sets of sup type and prove that they coincide with the Hörmander wave‐front set of a distribution. To that end we recall the notion of admissible lattice pairs and wave‐front sets in Fourier‐Lebesgue spaces. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Defect corrected averaging for parabolic PDEs
Authors: Naumann Andreas , Wensch Jörg
Published: November 2013

We consider parabolic partial differential equations with highly oscillatory source terms. The timescale of the problem is assumed to be much larger than the timescale of the oscillation. Resolution of the smallest timescale constitutes a strong restriction on the stepsize of time integration method. Averaging techniques like stroboscopic averaging have been developed to overcome this restriction. In case of parabolic equations these techniques are of limited advantage. We have developed defect corrected averaging techniques that allow timesteps taylored to the timescale of diffusion. They are based on Krylov subspace iterations for the abstract solution operator of the system. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Asymptotics and numerics for non‐Newtonian jet dynamics
Authors: Lorenz Maike , Marheineke Nicole , Wegener Raimund
Published: November 2013

This work deals with the modeling and simulation of non‐Newtonian jet dynamics. Proceeding from a 3d boundary value problem of upper‐convected Maxwell equations, a 1d viscoelastic string model can be derived asymptotically. The resulting system of PDEs has a hyperbolic‐elliptic character with an additional differential constraint. Its applicability regime is limited depending on physical parameters and boundary conditions. Numerical results are shown for gravitational in‐/outflow set‐ups. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An Optimal p‐Refinement Strategy for Dynamic Iteration of Ordinary and Differential Algebraic Equations
Authors: Schöps Sebastian , Bartel Andreas , Günther Michael
Published: November 2013

Multiphysical simulation tasks are often numerically solved by dynamic iteration schemes. Usually, this demands the efficient and stable coupling of existing simulation software for the contributing physical subdomains or subsystem. Since the coupling is weakened by such a simulation strategy, iteration is needed to enhance the quality of the numerical approximation. By the means of error recursions, one obtains estimates for the approximation order and the reduction of error per iteration (convergence rate). It is know that the first iterations can be coarsely sampled (in time), but the last iterations need to be refined (h‐refinement) to obtain the accuracy gain of latter iterations (‘sweeps’).

In this work we discuss an optimal choice of the approximation order p used in the time integration with respect to the iteration ‘sweep’ count. It is deduced from the analytical error recursion and yields a p‐refinement strategy. Numerical experiments show that our estimates are sharp and give a precise prediction of the correct convergence. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Two‐dimensional gel electrophoresis of gastric tissue in an alkaline pH range
Authors: Kočevar Nina , Grazio Snježana Frković , Komel Radovan
Published: November 2013

2DE in combination with MS has facilitated the discovery of several proteins with altered abundance in gastric cancer. While acidic and wide pH ranges have been widely investigated, analysis in the alkaline pH range has not been specifically performed in gastric cancer to date. In the present study, we initially optimized the 2DE in alkaline pH range (pH 7–11) for gastric tissue samples. Using a modified lysis buffer, we analyzed pooled nontumor and tumor samples for proteins with altered abundance in gastric adenocarcinoma. We successfully identified 38 silver‐stained spots as 24 different proteins. Four of these were chosen for investigation with immunoblotting on individual paired samples to determine whether the changes seen in 2DE represent the overall abundance of the protein or possibly only a single form. While mitochondrial trifunctional protein (MTP) subunits were decreased in 2DE gels, immunoblotting identified their overall abundance as being differently dysregulated: in the gastric tumor samples, the MTP‐α subunit was decreased, and the MTP‐β subunit was increased. On the other hand, heterogenous nuclear ribonucleoprotein M and galectin‐4 were increased in the gastric tumor samples in both 2DE and immunoblotting.
Single‐Chain Polymer Nanoparticles via Non‐Covalent and Dynamic Covalent Bonds
Authors: Sanchez‐Sanchez Ana , Pomposo José A.
Published: November 2013

The added value behind reversible bonds is the possibility to develop responsive structurally dynamic materials, which can adapt their constitution and, hence, properties to external stimuli. In recent years, much effort has been devoted to the design and synthesis of single‐chain polymer nanoparticles (SCNPs) that can be reversibly assembled or disassembled in response to external environmental changes or that can adapt even their structure through simple exchange reactions. Here, the evolution of the relatively new field of responsive SCNPs constructed via non‐covalent, or supramolecular, interactions, and “dynamic” covalent bonds is described in detail. The main reversible bonds commonly used in supramolecular polymer chemistry and dynamic covalent materials are summarized. A detailed description of the current reported routes to reversible unimolecular polymer nanoparticles is provided. Finally, future prospects of SCNPs constructed via supramolecular interactions and dynamic bonds are detailed.
Atom‐probe tomography study of boron precipitation in highly implanted silicon
Authors: Blavette Didier , Wang Huiyuan , Bonvalet Manon , Hüe Florian , Duguay Sébastien
Published: November 2013

Precipitation of boron in heavily doped silicon has been investigated using transmission electron microscopy (TEM) and atom‐probe tomography (APT). Si wafers were implanted with a very high boron dose (1 × 1017 at. cm−2) at 27 keV and further annealed at 500, 750 and 1000 °C for 1 h. Results show that precipitates nucleate during implantation before any annealing has been made. They were found to have a smaller boron content than that of the expected phase SiB3. With increasing thermal budget, the concentration of boron approaches the equilibrium composition 75 at.%. It is thought that small boron‐enriched precipitated clusters that form in supersaturated silicon should be distinguished from the boron interstitial clusters (BICs).
Systematic review and meta‐analysis of respiratory syncytial virus infection epidemiology in Latin America
Authors: Bardach Ariel , Rey‐Ares Lucila , Cafferata María Luisa , Cormick Gabriela , Romano Marina , Ruvinsky Silvina , Savy Vilma
Published: November 2013

Respiratory syncytial virus (RSV) is a frequent cause of acute respiratory infection and the most common cause of bronchiolitis in infants. The aim of this systematic review and meta‐analysis was to obtain a comprehensive epidemiological picture of the data available on disease burden, surveillance, and use of resources in Latin America. Pooled estimates are useful for cross‐country comparisons. Data from published studies reporting patients with probable or confirmed RSV infection in medical databases and gray literature were included from 74 studies selected from the 291 initially identified. When considering all countries, the largest pooled percentage RSV in low respiratory tract infection patients was found in the group between 0 and 11 months old, 41.5% (95% CI 32.0–51.4). In all countries, percentages were increasingly lower as older children were included in the analyses. The pooled percentage of RSV in LRTIs in the elderly people was 12.6 (95% CI 4.2–24.6). The percentage of RSV infection in hospitalized newborns was 40.9% (95% CI 28.28–54.34). The pooled case fatality ratio for RSV infection was 1.74% (95% CI 1.2–2.4) in the first 2 years of life. The average length of stay excluding intensive care unit admissions among children with risk factors for severe disease was 12.8 (95% CI 8.9–16.7) days, whereas it averaged 7.3 (95% CI 6.1/8.5) days in otherwise healthy children. We could conclude that infants in their first year of age were the most vulnerable population. To our knowledge, this is the first systematic review on RSV disease burden and use of health resources in Latin America. Copyright © 2013 John Wiley & Sons, Ltd.
Security of implantable medical devices: limits, requirements, and proposals
Authors: Ellouze Nourhene , Allouche Mohamed , Ahmed Habib Ben , Rekhis Slim , Boudriga Noureddine
Published: November 2013

Implantable medical devices (IMDs) are surgically implanted into a human body to collect physiological data and perform medical therapeutic functions. They are increasingly being used to improve the quality of life of patients by treating chronic ailments such as cardiac arrhythmia, diabetes, and Parkinson's disease. However, recent research has demonstrated the deficiency of wireless IMDs in enforcing security and privacy, and discussed the impact of these attacks on the patient's safety and efficacy of medical treatments. This paper provides an overview of the main vulnerabilities of IMDs. It also reviews the recent research on IMD security and privacy, and discusses their advantages and limitations. In this paper, we also describe the main requirements for improving security of IMDs and identify and discuss a set of research challenges for designing the next generation of secure wireless IMDs. Copyright © 2013 John Wiley & Sons, Ltd.
Teaching ESL/EFL in a World of Social Media, Mash‐Ups, and Hyper‐Collaboration
Authors: Kessler Greg
Published: November 2013

This article explores the emerging pedagogical potential offered by today's technologies and how understanding the relationship between emerging technology and emerging pedagogy can enhance the teaching of English as a second or foreign language (ESL/EFL). The author begins with an overview of recent developments in the field, focused upon pedagogical practice and computer‐assisted language learning (CALL), and then describes suggestions for incorporating various forms of social and new media within collaborative learning practices. By incorporating these forms of popular communication into language teaching, teachers can promote participation and engagement. They are also able to raise awareness of the benefits of various forms of literacy. The essay concludes with some thoughts about pedagogical and technological developments that teachers might anticipate in the future.
Dietary flavanol intervention lowers the levels of endothelial microparticles in coronary artery disease patients
Authors: Horn Patrick , Amabile Nicolas , Angeli Franca S. , Sansone Roberto , Stegemann Berthold , Kelm Malte , Springer Matthew L. , Yeghiazarians Yerem , Schroeter Hagen , Heiss Christian
Published: November 2013

Current evidence suggests that regenerative v. degenerative endothelial responses can be integrated in a clinical endothelial phenotype, reflecting the net result between damage from risk factors and endogenous repair capacity. We have previously shown that a cocoa flavanol (CF) intervention can improve endothelial function and increase the regenerative capacity of the endothelium by mobilising circulating angiogenic cells in patients with coronary artery disease (CAD). The aim of the present study was to investigate whether CF can lower the levels of circulating endothelial microparticles (EMP), markers of endothelial integrity, along with improvements in endothelial function. The levels of EMP in the frozen plasma samples of CAD patients were measured along with endothelial function (flow-mediated vasodilation, FMD); n 16, FMD data published previously), and these data were compared with those of young (n 12) and age-matched (n 12) healthy control subjects. The CAD patients exhibited significantly increased levels of EMP along with impaired FMD when compared with the healthy control subjects. The levels of CD144+ and CD31+/41− EMP were inversely correlated with FMD (r − 0·67, P= 0·01 and r − 0·59, P= 0·01, respectively). In these CAD patients, the levels of EMP were measured after they had consumed a drink containing 375 mg of CF (high-CF intervention, HiFI) or 9 mg of CF (macro- and micronutrient-matched low-CF control, LoFl) twice daily over a 30-d period in a randomised, double-blind, cross-over study. After 1 month of HiFI, the levels of CD31+/41− and CD144+ EMP decreased ( − 25 and − 23 %, respectively), but not after LoFl. Our data show that flavanols lower the levels of EMP along with higher endothelial function, lending evidence to the novel concept that flavanols may improve endothelial integrity.
Analyst Coverage, Information, and Bubbles
Authors: Andrade Sandro C. , Bian Jiangze , Burch Timothy R.
Published: November 2013

We examine the 2007 stock market bubble in China. Using multiple measures of bubble intensity for each stock, we find significantly smaller bubbles in stocks for which there is greater analyst coverage. We further show that the abating effect of analyst coverage on bubble intensity is weaker when there is greater disagreement among analysts. This suggests that, in line with resale option theories of bubbles, one channel through which analyst coverage may mitigate bubbles is by coordinating investors’ beliefs and thus reducing its dispersion. Stock turnover provides further evidence consistent with this particular information mechanism.
Argument ellipsis in Colloquial Singapore English and the Anti-Agreement Hypothesis
Authors: SATO YOSUKE
Published: November 2013

This paper provides new data from Colloquial Singapore English (CSE) showing a hitherto unnoticed subject–object asymmetry: empty objects, but not empty subjects, exhibit sloppy/quantificational readings. According to a recent theory of argument ellipsis in Japanese/Korean (Oku 1998; S. Kim 1999; Takahashi 2007, 2008a, b, 2010), these readings obtain as a result of the LF-Copy of an overt argument from a full-fledged clause onto the corresponding empty argument position in an elliptical clause. Şener & Takahashi (2010) and Takahashi (2010) hypothesize that this operation is blocked by ϕ-agreement. This hypothesis provides a principled explanation for the subject–object asymmetry in CSE, coupled with the new observation that primary substrates of CSE – Mandarin, Cantonese, Hokkien and Malay – exhibit the same asymmetry as CSE. My analysis has significant implications for the comparative syntax of argument ellipsis and for theories of contact genesis. Among others, the analysis supports the claim (Miyagawa 2010) that Chinese possesses ϕ-agreement despite the lack of morphological manifestations. The results in this paper also provide strong evidence for the general substratist explanation on the emerging grammar of CSE (Bao 2005).
Multilingualism in Canada: Policy and Education in Applied Linguistics Research
Authors: Dagenais Diane
Published: November 2013

Increasing multilingualism in Canada has captured the interest of applied linguists who investigate what it implies for policy and educational practice. This article provides a review of recent discussions of Canadian policy in the literature, current research on multilingual learners, and emerging innovations in multilingual pedagogies. The literature on policy indicates that some researchers treat policy as text and identify disjunctions between policy documents and the reality of a linguistically and culturally diverse population, while others view it as discursive practice and document how policy is constructed locally through language in response to a changing environment. The research on multilingual learners is based primarily on field-based reports that reveal how multilingual language practices are complex, dynamic, and ideological, and are tied to identity construction. The growing number of innovations in multilingual pedagogies suggests that more educators are beginning to see identity work and multimodal literacies as central to teaching students of diverse origins. This article concludes that there is a gap between official language policy and research on multilingualism in Canada.
Multilingualism in the Workplace
Authors: Gunnarsson Britt-Louise
Published: November 2013

This survey article presents studies on multilingualism in the workplace carried out in different regions. One aim is to give a cross-cultural picture of workplace studies on different languages, and another is to discuss both positive and problem-based accounts of multilingualism at work. The conditions for workplace discourse have been influenced by a series of changes taking place in recent decades. Technological advances have led to new types of networks and workplaces, making linguistic issues salient, at the same time as many low-paid workers are found in traditional jobs, for which the face-to face interaction is central. A model is presented, the aim of which is to grasp the complex and dynamic interplay between workplace discourse and its various contextual frames. Overviews of studies on multilingualism at work are discussed with a focus on workplaces in the inner, outer, and expanding English circles; in transnational companies; and in multilingual regions and English lingua franca workplaces in Europe. Workplaces with workforce diversity are also dealt with. In the discussion section, the scope is enlarged and workplace discourse is related to various contextual frameworks. Finally, some key topics for future studies are sketched.
Mediterranean diet and health status: an updated meta-analysis and a proposal for a literature-based adherence score
Authors: Sofi Francesco , Macchi Claudio , Abbate Rosanna , Gensini Gian Franco , Casini Alessandro
Published: November 2013

Objective

To update previous meta-analyses of cohort studies that investigated the association between the Mediterranean diet and health status and to utilize data coming from all of the cohort studies for proposing a literature-based adherence score to the Mediterranean diet.

Design

We conducted a comprehensive literature search through all electronic databases up to June 2013.

Setting

Cohort prospective studies investigating adherence to the Mediterranean diet and health outcomes. Cut-off values of food groups used to compute the adherence score were obtained.

Subjects

The updated search was performed in an overall population of 4 172 412 subjects, with eighteen recent studies that were not present in the previous meta-analyses.

Results

A 2-point increase in adherence score to the Mediterranean diet was reported to determine an 8 % reduction of overall mortality (relative risk = 0·92; 95 % CI 0·91, 0·93), a 10 % reduced risk of CVD (relative risk = 0·90; 95 % CI 0·87, 0·92) and a 4 % reduction of neoplastic disease (relative risk = 0·96; 95 % CI 0·95, 0·97). We utilized data coming from all cohort studies available in the literature for proposing a literature-based adherence score. Such a score ranges from 0 (minimal adherence) to 18 (maximal adherence) points and includes three different categories of consumption for each food group composing the Mediterranean diet.

Conclusions

The Mediterranean diet was found to be a healthy dietary pattern in terms of morbidity and mortality. By using data from the cohort studies we proposed a literature-based adherence score that can represent an easy tool for the estimation of adherence to the Mediterranean diet also at the individual level.
POLYNOMIAL EQUIVALENCE OF FINITE RINGS
Authors: GRASEGGER GEORG , HORVÁTH GÁBOR , KEARNES KEITH A.
Published: November 2013

We prove that ${ \mathbb{Z} }_{{p}^{n} } $ and ${ \mathbb{Z} }_{p} [t] / ({t}^{n} )$ are polynomially equivalent if and only if $n\leq 2$ or ${p}^{n} = 8$. For the proof, employing Bernoulli numbers, we explicitly provide the polynomials which compute the carry-on part for the addition and multiplication in base $p$. As a corollary, we characterize finite rings of ${p}^{2} $ elements up to polynomial equivalence.
Endemic thelodonts (Vertebrata: Thelodonti) from the Lower Silurian of central Asia and southern Siberia
Authors: Žigaitė Živilė
Published: November 2013

New fossil vertebrate microremains from the Lower Silurian of NW Mongolia, Tuva and S Siberia have been discovered, and previous collections of thelodonts (Vertebrata: Thelodonti) from this region re-studied, figured and described, following recent advances in morphology and systematics of thelodont scales. As a result, six thelodont species are described here and attributed to two families and three genera. An emended diagnosis is given for each species. Morpohological scale varieties of each species are revised, and the squamation types are introduced to the species descriptions, resulting in newly grouped morphological sets of scales. The previously monotypic genusTalimaalepisŽigaitė, 2004, is proposed to contain two different species; therefore, two new combinations of morphological scale sets of two species are described for the first time. Both of them show transitional scale structure between the generaLoganellia(family Loganellidae) andHelenolepis(family Phlebolepididae). Two of the thelodont genera,AngaralepisandTalimaalepis, as well as all the six species, are endemic and not known anywhere else in the world. They are accompanied by a variety of other peculiar early vertebrates, such as mongolepids, two endemic genera of acanthodians, and putative galeaspids. This work enhances our knowledge of early Silurian vertebrate diversity, and provides evidence of regional palaeoenvironmental conditions and palaeogeographical relationships of the Siberia and Tuva terranes.