bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unbiased ensemble square root filters
Authors: Dance S. L. , Livings D. M. , Nichols N. K. 
Published: October 2008

AbstractEnsemble square root filters are a method of data assimilation, where model forecasts are combined with observations to produce an improved state estimate, or analysis. There are a number of different algorithms in the literature and it is not clear which of these is the best for any given application. This work shows that in some implementations there can be a systematic bias in the analysis ensemble mean and consequently an accompanying shortfall in the spread of the analysis ensemble as expressed by the ensemble covariance matrix. We have established a set of necessary and sufficient conditions for the scheme to be unbiased. While these conditions are not a cure‐all and cannot deal with independent sources of bias such as model and observation errors, they should be useful to designers of ensemble square root filters in the future. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On coupled problems in geomechanics
Authors: Ehlers Wolfgang , Graf Tobias , Acartürk Ayhan 
Published: October 2008

AbstractGeomechanical problems are generally based on the category of granular, cohesive‐frictional materials with a fluid pore content. At the macroscopic scale of continuum mechanics, these materials can be successfully described on the basis of the well‐founded Theory of Porous Media (TPM) [1].The present contribution touches fundamental problems of coupled media by investigating the interacting behaviour of an elasto‐viscoplastic porous solid skeleton, the soil, and two pore fluids, water and air. Furthermore, electro‐chemical reactions are considered in order to include the swelling behaviour of active soil. In conclusion, this leads to a system of strongly coupled partial differential equations (PDE) that can be solved by use of the finite element method (FEM). In particular, the presentation includes fluid‐flow situations in the fully or the partially saturated range, swelling phenomena of active clay [3] as well as localisation phenomena [2] as a result of fluid flow or heavy rainfall events. The computations are carried out by use of the single‐processor FE tool PANDAS [4] and, in case of large 3‐d problems, by coupling PANDAS with the multi‐processor solver M++. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On necessary conditions for state constrained problems
Authors: Pinho M. d. R. de , Ferreira M. M. A. , Fontes F. A. C. C. 
Published: October 2008

AbstractNecessary conditions of optimality in the form of Unmaximized Inclusions (UI) were derived for optimal control problems with pathwise state inequality constraints. An approach similar to that used to derive such type of necessary conditions can be followed to obtain relaxation of hypotheses previously imposed on the regularity of the state constraint function. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the interaction of geometry, analysis and stochastics on a body
Authors: Freiberg Uta R. 
Published: October 2008

AbstractIt is reasonable to expect that the geometrical feature of a body has influence to spectral asymptotics of its “natural” Laplacian as well as to the behavior of its “natural” Brownian motion. In fact, such an interaction can be expressed by a so–called “Einstein relation” implicating Hausdorff, spectral and walk dimension. These quantities express geometric, analytic and stochastic aspects of a set. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An interval arithmetic scheme for analyzing uncertain systems
Authors: Gaull Andreas , Kreuzer Edwin 
Published: October 2008

AbstractThis contribution is dedicated to the numerical study of the global behavior of dynamical systems whose mathematical descriptions are imperfect due to uncertainties concerning involved parameters. At the beginning, we constitute themathematical model in order to provide a tailor‐made framework dealing with this problem. Here, uncertainties are regarded as external random noise or perturbations influencing an underlying deterministic system. Afterwards, an interval arithmetic scheme is presented which allows the numerical evaluation of the model. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nonlinear iterative operator splitting methods and applications for nonlinear differential equations
Authors: Geiser Jürgen 
Published: October 2008

AbstractIn this paper we discuss decomposition methods that are used for solving nonlinear differential equations. The motivation arose from the need to decouple nonlinear operator equations into simpler, computable operator equations [1]; [2]. We consider iterative operator‐splitting methods for the decoupling of the differential equations and we apply iterative steps to achieve linearisation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Material force method within the framework of the X‐FEM‐distribution of nodal material forces
Authors: Glaser J. , Steinmann P. 
Published: October 2008

AbstractThe Material Force Method (MFM) and the Extended Finite Element Method (X‐FEM), both have been major subjects of computational fracture mechanics in recent time. Thus combining the advantages of both concepts [1, 2] seems a promising approach to describe the behaviour of discontinuities such as cracks in otherwise continuous bodies. As the X‐FEM models a crack independently of the mesh, the crack tip is in general not located at a node which is why a central question is, which nodal material forces do contribute to the resulting material force vector at the crack tip. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Uncertainty quantification for chaotic fluid dynamics
Authors: Glimm James , Jin Hyeonseong 
Published: October 2008

AbstractWe study mesh convergence issues for a representative chaotic flow problem. Convergence in the sense of pointwise convergence fails as new structures emerge with each new level of mesh refinement. We formulate convergence in terms of statistical averages. Care is made to divide the problem into homogeneous regions, and statistical convergence is found for each such region. Automated feature extraction is the tool used for this decomposition.We study of averaged equations, and the closure problem which arises in their derivation. The accuracy of the closure terms is discussed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Micromechanical modeling of twinning
Authors: Glüge R. , Böhlke T. 
Published: October 2008

AbstractThere exist material models that incorporate mechanical twinning in a homogenized sense, or consider specific aspects, like grain refinement or texture evolution. However, since the RVE‐technique became a standard method, it is possible to obtain more detailed predictions based on micromechanical models. In this work, an approach based on a nonconvex elastic potential and the corresponding results of FE calculations are presented. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Finite thermo‐viscoplasticity of amorphous glassy polymers: Experiments, modeling and simulations
Authors: Göktepe Serdar , Méndez Joel , Miehe Christian 
Published: October 2008

AbstractThe contribution is concerned with experimental procedures, constitutive modeling and the numerical simulations of finite thermo‐viscoplastic behavior of glassy polymers. The experimental study involves both homogeneous and inhomogeneous tests at different temperatures under isothermal conditions. The true stress‐true strain curves obtained from compressive homogeneous uniaxial and plane strain experiments are employed in the identification of adjustable material parameters. In contrast to the existing kinematic approaches to finite plasticity of glassy polymers, we propose a distinct kinematic framework constructed in the logarithmic strain space. This leads us to an algorithmically very attractive, additive kinematic structure in R6 similar to the geometrically linear theory. The proposed three‐dimensional model is implemented into a finite element code. The load‐displacement curves acquired from inhomogeneous experiments are compared against the results obtained from finite element analyses where the material parameters identified from homogeneous experiments are used. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimal control for supply network models: Mixed integer programming
Authors: Göttlich Simone , Herty Michael 
Published: October 2008

AbstractThe aim of our investigations is the optimization of a continuous model for a special class of supply networks. We focus on the underlying fundamentals and show the relation to mixed‐integer programming. This is done by applying numerical discretization schemes to the dynamics of the continuous equations and by approximations to the cost functional. One benefit of the MIP model is the adaptivity to real‐world situations by adding reasonable extensions such as bounded queues. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Slant Newton method for elastoplastic problems with linear hardening and its local super‐linear convergence
Authors: Gruber Peter G. , Valdman Jan 
Published: October 2008

AbstractElastoplastic problems frequently arise in the science of structural mechanics. Such problems are nonlinear and time dependent, but if one assumes an already discrete model with respect to time, the task is to efficiently solve a one time step problem. In this article we present a solution algorithm for a one time step problem and discuss its super‐linear convergence rate. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stochastic binding of Ca2+ ions in the dyadic cleft; continuous vs random walk description of diffusion
Authors: Hake Johan , Lines Glenn Terje 
Published: October 2008

AbstractCa2+ signaling in the dyadic cleft in ventricular myocytes is fundamentally discrete and stochastic. In this paper we study the stochastic binding of single Ca2+ ions to receptors in the cleft using two different models of diffusion; a stochastic and discrete Random walk (RW) model, and a deterministic continuous model. We investigate if the latter model, together with a stochastic receptor model, can reproduce binding events registered in fully stochastic RW simulations. By evaluating the continuous model goodness‐of‐fit, we present evidences that it can. The large fluctuations in binding rate observed at the time level of single time steps are integrated and smoothed at the larger time scale of binding events, explaining the continuous model goodness‐of‐fit. With this we demonstrate that the stochasticity and discreteness of the Ca2+ signaling in the dyadic cleft, determined by single binding events, can be described with a deterministic model of Ca2+ diffusion together with a stochastic model of the binding events. Time consuming RW simulations can thus be avoided. We also present a new analytical model of bi‐molecular binding probabilities that is used in the RW simulations, and in the statistical analysis. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling and computation of metal powder compaction processes
Authors: Hartmann Stefan , Bier Wolfgang 
Published: October 2008

AbstractIn this short communication the numerical treatment of a thermomechanical consistent finite strain viscoplasticity model for metal powder compaction is discussed. The convex single surface yield function evolves according to two evolution equations and remains convex under all loading conditions. The very challenging numerical treatment on local level for integrating the constitutive model requires particular globally convergent Newton‐like method with inequality constraints so that a stable solution scheme results. This is embedded into a time‐adaptive finite element program which makes use of diagonally‐implicit Runge‐Kutta methods combined with a Multilevel‐Newton algorithm. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Two‐scale simulation of damage in unidirectionally fibre reinforced composite materials
Authors: Koester B. , Matzenmiller A. 
Published: October 2008

AbstractThe finite element analysis of engineering structures usually assumes a homogeneous as well as a continuous medium. The heterogeneity of matter, which is always found on a sufficiently small length scale is neglected by replacing the inhomogeneous medium through a model of a mathematically homogenized material. The macroscopic constitutive behaviour is derived from volume averaging procedures that smear the microscopic heterogeneities. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Signal propagation through dense granular systems
Authors: Kondic L. , Behringer R. P. 
Published: October 2008

AbstractThe exact manner in which signals propagate through dense granular systems is still open for discussion. In this work, we present the results of discrete element simulations of the system response to space and time dependent perturbations. Fourier analysis of the system response shows that the properties of the propagating signal strongly depend on the spatial scales introduced by the perturbation itself. The presented results are expected to serve as a basis for development of a continuum model that will describe propagation of signals through dense granular systems. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of the non‐linear contact stiffness on the vibration behaviour of a tyre tread block
Authors: Kröger M. , Moldenhauer P. , Gäbel G. 
Published: October 2008

AbstractThe dynamic behaviour of a tyre tread block is described by a modularly arranged model. Special emphasis is laid on the influence of the force‐displacement characteristic between rubber and the rough surface. In the simulation the rough surface on which the tread block slides is modelled as smooth with the friction characteristic of the respective material pairing and a non‐linear description of the local tyre/road interaction. This leads to an adequate description of the contact partners without losing numerical efficiency. Furthermore the model considers wear that changes the block geometry and thus the vibrational behaviour. With the presented model of a tyre tread block dynamic effects like friction induced vibrations are simulated. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On tangential stabilization in curvature driven flows of planar curves
Authors: Mikula Karol , Ševčovič Daniel 
Published: October 2008

AbstractWe discuss the role of tangential stabilization in a curvature driven flow of planar curves. The governing system of nonlinear parabolic equations includes a nontrivial tangential velocity functional yielding a uniform redistribution of grid points along the evolving family of curves preventing numerically computed curves from forming various instabilities. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermal annealing behavior of silica‐coated coaxial nanowires
Authors: Kim Hyoun Woo , Lee Jong Woo , Lee Changmu , Kebede Mesfin A. 
Published: October 2008

AbstractThe effects of thermal annealing on structural and optical properties of MgO‐core–silica (SiOx)‐shell nanowires have been investigated. The annealed nanostructures consisted of a crystalline MgO core surrounded by an amorphous SiOx shell layer, whereas the shell surface had become rough and an Mg2SiO4 phase appeared by annealing at a sufficiently high temperature of 800°C. Photoluminescence (PL) measurements of annealed MgO‐core/SiOx‐shell nanowires indicated that the overall intensities increased on increasing the annealing temperature, with the overall shapes of the emission spectra being independent of the annealing temperature from 600 to 1000°C. This study provides an insight into the annealing studies involving various coaxial nanowires. Copyright © 2008 John Wiley & Sons, Ltd.
Hypercalcemia and 13‐cis‐retinoic acid in post‐consolidation therapy of neuroblastoma
Authors: Marabelle Aurélien , Sapin Vincent , Rousseau Raphaël , Periquet Brigitte , Demeocq François , Kanold Justyna 
Published: October 2008

AbstractWe report 19 episodes of hypercalcemia in three children treated with 13‐cis‐retinoic acid (13‐cis‐RA) as a post‐consolidation therapy for high‐risk neuroblastoma. There was no concomitant overload in 13‐cis‐RA blood levels. Blood calcium fell after arrest of 13‐cis‐RA intake. Half dosage retinoid treatment resumption did not prevent the recurrence of hypercalcemia. Concomitant biological values showed massive bone resorption. Hence, hypercalcemia seemed not secondary to 13‐cis‐RA overload but rather to inter‐individual variability in its interaction with bone metabolism. Current guidelines in case of hypercalcemia are to reduce 13‐cis‐RA dosage. Instead we propose to maintain the therapeutic dosage, but to shorten the duration of courses. Pediatr Blood Cancer 2009;52:280–283. © 2008 Wiley‐Liss, Inc.
Quantitative phosphoproteomics – an emerging key technology in signal‐transduction research
Authors: Schreiber Thiemo B. , Mäusbacher Nina , Breitkopf Susanne B. , Grundner‐Culemann Kathrin , Daub Henrik 
Published: October 2008

AbstractProtein phosphorylation is the most important type of reversible post‐translational modification involved in the regulation of cellular signal‐transduction processes. In addition to controlling normal cellular physiology on the molecular level, perturbations of phosphorylation‐based signaling networks and cascades have been implicated in the onset and progression of various human diseases. Recent advances in mass spectrometry‐based proteomics helped to overcome many of the previous limitations in protein phosphorylation analysis. Improved isotope labeling and phosphopeptide enrichment strategies in conjunction with more powerful mass spectrometers and advances in data analysis have been integrated in highly efficient phosphoproteomics workflows, which are capable of monitoring up to several thousands of site‐specific phosphorylation events within one large‐scale analysis. Combined with ongoing efforts to define kinase‐substrate relationships in intact cells, these major achievements have considerable potential to assess phosphorylation‐based signaling networks on a system‐wide scale. Here, we provide an overview of these exciting developments and their potential to transform signal‐transduction research into a technology‐driven, high‐throughput science.
Proteomics and phosphoproteomics for the mapping of cellular signalling networks
Authors: Preisinger Christian , von Kriegsheim Alex , Matallanas David , Kolch Walter 
Published: October 2008

AbstractProteomics is transitioning from inventory mapping to the mapping of functional cellular contexts. This has been enabled by progress in technologies as well as conceptual strategies. Here, we review recent advances in this area with focus on cellular signalling pathways. We discuss genetics‐based methods such as yeast two hybrid methods as well as biochemistry‐based methods such as two‐dimensional gel electrophoresis, quantitative proteomics, interaction proteomics, and phosphoproteomics. A central tenet is that by its ability to capture dynamic changes in protein expression, localisation and modification modern proteomics has become a powerful tool to map signal transduction pathways and deliver the functional information that will promote insights in cell biology and systems biology.
Plasma Etching and Roughening of Thin Polymeric Films: A Fast, Accurate, in situ Method of Surface Roughness Measurement
Authors: Kokkoris George , Vourdas Nikolaos , Gogolides Evangelos 
Published: October 2008

AbstractA method is proposed to measure the root mean square surface roughness (hrms) of thin polymeric films on hard substrates during plasma etching. It utilizes in situ monitoring of the film thickness versus etching time by spectroscopic ellipsometry to extract the height distribution and hrms at the corner point (CP). The CP is the time instant where etching rate starts to gradually drop; it depends on the initial film thickness, and denotes the gradual exposure of the hard substrate to the plasma due to the advancement of the rough etch front. The hrms is found equal to approximately half of the remaining thickness at CP. The method compares well with atomic force microscopy measurements.magnified image
Overexpression and elevated plasma level of tumor‐associated antigen 90K/Mac‐2 binding protein in colorectal carcinoma
Authors: Wu Chih‐Ching , Huang Yu‐Shan , Lee Li‐Yu , Liang Ying , Tang Rei‐Ping , Chang Yu‐Sun , Hsieh Ling‐Ling , Yu Jau‐Song 
Published: October 2008

AbstractThe cancer cell secretome may contain potentially useful biomarkers. Previously, we have analyzed the colorectal carcinoma (CRC) cell secretome. In this study, tumor‐associated antigen 90K (TAA90K)/Mac‐2 binding protein (Mac‐2BP), one of the CRC cell secreted proteins, was chosen for evaluation as a potential CRC biomarker because its mRNA level was also found to be significantly elevated in CRC tissues and in a more metastatic CRC cell line from the analysis of two public domain array‐based datasets. Immunohistochemical analysis of 241 CRC specimens showed that TAA90K/Mac‐2BP was positively detected in 52.7% of the tumors, but weakly or not detected in over 95% of the adjacent nontumor epithelial cells. The plasma TAA90K/Mac‐2BP levels were significantly higher in CRC patients (N = 280) versus healthy controls (N = 147) (7.77 ± 3.49 vs. 5.72 ± 2.67 μg/mL, p<0.001). Moreover, combination of TAA90K/Mac‐2BP and carcinoembryonic antigen (CEA) could outperform CEA alone in discriminating CRC patients from healthy persons in this case‐control study. Our results collectively indicate that analysis of cancer cell secretome is a feasible strategy for identifying cancer biomarker candidates, and the TAA90K/Mac‐2BP may be a potential CRC biomarker.
Fast‐response organic–inorganic hybrid light‐emitting diode
Authors: Fukuda Takeshi , Wei Bin , Suto Eiichi , Ichikawa Musubu , Taniguchi Yoshio 
Published: October 2008

AbstractWe demonstrated important changes produced on the modulation frequency of hybrid organic–inorganic light‐emitting diodes to examine the applicability as a light source for visible optical communications. The fabricated device structure was 4,4′‐bis[N ‐(1‐napthyl)‐N ‐phenyl‐amino]biphenyl/4,4′‐(bis(9‐ethyl‐3‐carbazovinylene)‐1,1′‐biphenyl:4,4′‐bis[9‐dicarbazolyl]‐2,2′‐biphenyl/ZnS/LiF/MgAg. This device showed an improvement in the modulation frequency using ZnS instead of an organic material, tris(8‐hydroxyquinoline)aluminum. A maximum cutoff frequency of 20.6 MHz was achieved.magnified image(© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Low intensity directional switching of light in semiconductor microcavities
Authors: Schumacher Stefan , Kwong N. H. , Binder R. , Smirl Arthur L. 
Published: October 2008

AbstractRecently it was demonstrated that in atomic vapors weak control beams can manipulate (or switch) the propagation direction of strong light beams [Dawes et al., Science 308, 672 (2005)]. As a semiconductor analog of such all‐optical switching, we present a proposal for similar manipulation and switching in planar semiconductor microcavities. Using a microscopic many‐particle theory, we investigate the spatio‐temporal dynamics of four‐wave mixing signals and related instabilities in these systems. Even though the underlying physical processes are different from atomic systems, we find that microcavities allow for reversible directional manipulation of light. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Efficient VUV sensitization of Eu3+ emission by Tb3+ in potassium rare‐earth double phosphate
Authors: Mikhailik V. B. , Kraus H. , Dorenbos P. 
Published: October 2008

AbstractThe luminescence properties of K3Tb(PO4)2 activated by Eu3+ were studied at excitation over the 120–300 nm wavelength range. It is demonstrated that Tb3+ ions, exhibiting a strong absorption band in the vacuum‐ultraviolet (VUV), can provide efficient sensitisation of Eu3+ emission in this wave length range, giving rise to intense red luminescence at 150 nm excitation. A proof is given for the concept of VUV sensitisation enabling the engineering of luminescence materials with enhanced conversion efficiency of VUV radiation into visible light. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)