bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tensegrities
Authors: Servatius Brigitte 
Published: September 2008

AbstractTensegrities, or tensed frameworks, are objects that fit well in the domain of metric geometry and combinatorics. Questions of rigidity and stability were already asked by architectural designers like Fuller and Emmerich and also by the artist Snelson in the 1960s and 1970s. Key results and conjectures of that time are compiled in Branko Grünbaum's Lectures in lost mathematics. Recent mathematical progress has paved the way to new applications in the biological sciences as well as in structural engineering. The talks in this minisymposium, whose content is summarized here, intended to communicate this progress to researchers in the fields of mathematics, computer science, biology, and mechanical engineering. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Homogeneous groups and multiscale intensity models for multiname credit derivatives
Authors: Papageorgiou Evan , Sircar Ronnie 
Published: September 2008

AbstractWe discuss a computationally tractable approach to the valuation of multiname credit derivatives employing name grouping for dimension reduction, and singular perturbation approximations for model robustness. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On an application of the QMR_SYM method to complex symmetric shifted linear systems
Authors: Sogabe T. , Hoshi T. , Zhang S.‐L. , Fujiwara T. 
Published: September 2008

AbstractWe consider the solution of complex symmetric shifted linear systems. Such systems arise in large scale electronic structure theory and there is a strong need for the fast solution of the systems. In this paper, we describe an algorithm for solving the systems, which is based on the QMR_SYM method for solving complex symmetric linear systems. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hydrodynamic stability control in CFD by shape optimization
Authors: Heuveline Vincent , Strauß Frank 
Published: September 2008

AbstractWe propose a numerical scheme which aims at solving shape optimization problems in the context of hydrodynamic stability. It is the goal to minimize the drag and ensure hydrodynamic stability by modification of parts of the underlying geometry. The stability issues are represented by eigenvalue constraints. Numerical results for a test case show that a transition from an unstable design into a stable one is attainable by considering an adequate change of the geometry. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Global attractivity conditions for a single species model
Authors: Tkachenko Viktor , Trofimchuk Sergei 
Published: September 2008

AbstractWe give sharp conditions for global attractivity of the zero solution of the nonlinear difference equation which arises in many contexts in mathematical biology xn +1 = qxn + fn (xn , …, xn –k ), n ∈ ℤ, where q ∈ (0,1] and functions fn satisfy the generalized Yorke conditions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A parallel Krylov‐Schur implementation for large Hermitian and non‐Hermitian eigenproblems
Authors: Hernández V. , Roman J. E. , Tomás A. 
Published: September 2008

AbstractThis work presents a new implementation of a Krylov‐Schur eigensolver in SLEPc (Scalable Library for Eigenvalue Problem Computations), a software library for the solution of large, sparse eigenvalue problems on parallel computers. Some parallel performance results are given, showing better scalability compared to ARPACK. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical techniques for ice masses dyamics simulation by using a complete shallow ice approximation
Authors: Calvo N. , Durany J. , Toja R. , Vázquez C. 
Published: September 2008

AbstractIn this work a complex coupled shallow ice model which governs the thermal, hydrodynamic and mechanical processes in the dynamics of large ice masses is proposed and solved by means of efficient numerical techniques. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Robust expansion of subspaces in iterative projection methods for large eigenvalue problems
Authors: Voss Heinrich 
Published: September 2008

AbstractThe Jacobi–Davidson method is known to converge at least quadratically if the correction equation is solved exactly, and it is common experience that the fast convergence is maintained if the correction equation is solved only approximately. Here we derive the Jacobi–Davidson method in a way that explains this robust behavior. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical simulation of nonlinear electro‐elastostatics
Authors: Vu D. K. , Steinmann P. , Possart G. 
Published: September 2008

AbstractThe numerical simulation of nonlinear electro‐elastostatics is addressed in this work. Based on the governing equations of the electric field and the governing equations of non‐linear elastostatics, a variational formulation is formulated and the finite element method is employed to solve the non‐linear electro‐mechanical coupling problem. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical solution of Volterra integro‐differential equations modelling thalamo‐cortical systems
Authors: Zubik‐Kowal B. , Jackiewicz Z. , Hoppensteadt F.C. 
Published: September 2008

AbstractOur study concerns thalamo‐cortical systems which are modelled by nonlinear systems of Volterra integro‐differential equations of convolution type. The thalamo‐cortical systems describe a new architecture for a neurocomputer. Such a computer employs principles of human brain. It consists of oscillators which have different frequencies and are weakly connected via a common medium forced by an external input.Since a neurocomputer consists of many interconnected oscillators (referred also as neurons), the thalamo‐cortical systems include large numbers of Volterra integro‐differential equations. Solving such systems numerically is expensive not only because of their large dimensions but also because of many kernel evaluations which are needed over the whole interval from the initial point, where the initial condition is imposed, up to the present point, where the computations are currently executed. Moreover, the whole computed history of the solution has to be stored in the memory of the computing machine. Therefore, robust and efficient numerical algorithms are needed for computer simulations for the solutions to the thalamocortical systems.In this paper, we illustrate an iteration technique to solve the thalamo‐cortical systems. The proposed successive iterates are vector functions of time, which change the original problems into systems of easier and separated equations. Such separated equations can then be solved in parallel computing environments. Results of numerical experiments are presented for large numbers of oscillators. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Myeloablative chemotherapy with autologous bone marrow rescue in children and adolescents with recurrent malignant astrocytoma: Outcome compared with conventional chemotherapy: A report from the Children's Oncology Group
Authors: Finlay Jonathan L. , Dhall Girish , Boyett James M. , Dunkel Ira J. , Gardner Sharon L. , Goldman Stewart , Yates Allan J. , Rosenblum Marc K. , Stanley Philip , Zimmerman Robert A. , Wallace Dana , Pollack Ian F. , Packer Roger J. ,   for the Children's Cancer Group
Published: September 2008

AbstractPurposeChildren and adolescents with malignant astrocytomas recurring after initial treatment have a dismal prognosis, with only rare patients surviving 1‐year beyond recurrence. The purpose of this study was to attempt to improve their survival.MethodsTwenty‐seven children and adolescents with malignant astrocytomas [17 glioblastoma multiforme and 10 anaplastic astrocytoma (AA)] following initial tumor progression, received myeloablative chemotherapy followed by autologous marrow rescue with one of three thiotepa and etoposide‐based chemotherapy regimens, administered alone (n = 11) or combined with carmustine (n = 5) or carboplatin (n = 11). Time to progression and death following myeloablative chemotherapy for these patients was compared non‐randomly with outcome of a contemporaneously treated cohort of similar patients who received only conventional chemotherapy following initial tumor progression. The two cohorts were compared for age, histology, prior therapies, extent of surgical resection at progression, and time from initial diagnosis to progression.ResultsFive of 27 children (two with glioblastoma multiforme and three with AA) survive event‐free from 8.3 to 13.3 years (median of 11.1 years) following myeloablative chemotherapy. Of 56 children with recurrent malignant astrocytoma who received conventional chemotherapy following initial progression, no patient survives. Differences in distributions of survival were not significant when stratified by surgical debulking (P = 0.39). However, for patients who were surgically debulked, the survival distributions are significantly different (P = 0.017).ConclusionsMyeloablative chemotherapy with autologous marrow rescue can produce durable remissions in children and young adults with recurrent malignant gliomas, in the setting of minimal residual tumor burden achieved surgically. Pediatr Blood Cancer 2008;51:806–811. © 2008 Wiley‐Liss, Inc.
Outcome and toxicity of chemotherapy for acute lymphoblastic leukemia in children with down syndrome
Authors: Shah Niketa , Al‐Ahmari Ali , Al‐Yamani Arwa , Dupuis Lee , Stephens Derek , Hitzler Johann 
Published: September 2008

AbstractBackgroundAcute lymphoblastic leukemia (ALL) in children with Down syndrome (DS) presents with an increased incidence, higher frequency of adverse effects and inferior probability of survival. Attempts at improving outcomes face the dilemma posed by the need to avoid excessive toxicity while maintaining the efficacy of treatment. Dose reductions and avoidance of infusions of intermediate and high‐dose methotrexate are common in this group.ProcedureIn a matched pair analysis we compared adverse effects and survival after ALL chemotherapy using intermediate and high doses of methotrexate in children with and without Down syndrome.ResultsFollowing intermediate and high doses of methotrexate to treat primary ALL, children with DS did not require opiate analgesia and parenteral nutrition for severe mucositis more often than children without DS. Children with DS spent more days in hospital and missed more doses of maintenance chemotherapy. Chemotherapy dose reductions were common and in this study had no detectable adverse impact. Event‐free and overall survival (OS) of children with ALL was lower in the DS than the non‐Down syndrome (NDS) control group. The difference, however, was no longer significant during the recent treatment era.ConclusionsThe feasibility of all treatment elements that are efficacious in pediatric ALL needs to be carefully considered in children with DS. In addition to survival data, the prospective collection of data on both adverse events and treatment modifications is essential to strike a balance between the avoidance of adverse effects and the need for intensive therapy that will safely improve ALL outcomes in this group. Pediatr Blood Cancer 2009;52:14–19. © 2008 Wiley‐Liss, Inc.
Defect characterization and analysis of III‐V nanowires grown by Ni‐promoted MBE
Authors: Lari L. , Murray R. T. , Gass M. H. , Bullough T. J. , Chalker P. R. , Kioseoglou J. , Dimitrakopulos G. P. , Kehagias Th. , Komninou Ph. , Karakostas Th. , Chèze C. , Geelhaar L. , Riechert H. 
Published: September 2008

AbstractWe report on transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) analysis of GaN and Al0.2Ga0.8N nanowires (NWs) grown by radio frequency plasma assisted Molecular Beam Epitaxy (PAMBE) on c‐sapphire substrates. Conventional TEM images of single nanowires removed from the substrate exhibit a high density of basal stacking faults. Further analyses were performed using the aberration‐corrected SuperSTEM facility. Geometric phase analysis (GPA) was applied to this data revealing the characteristic lattice displacement introduced by intrinsic basal stacking faults. The nickel‐based “seeds”, which were employed to promote the NW‐type growth, are found to be situated at the tip of each nanowire. Different types of analyses were applied to lattice images of these seeds including GPA, projection method analysis and Fast Fourier transform of the HREM images. All three approaches yielded lattice constants and displacements with good agreement. The measured lattice values in the GaN nanowire body were in good agreement with the lattice constants of relaxed bulk GaN. For the seed particles the resulting lattice spacing was attributable, within the experimental error, to either nickel oxide, Ni3Ga, or an intermediate alloy phase. The defect density was measured in the AlGaN nanowires and was found to be in the order of 106 cm–1. The results are critically discussed in relation to the possible growth mechanisms of the NWs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Strain relaxation in AlN/GaN heterostructures grown by molecular beam epitaxy
Authors: Dimitrakopulos G. P. , Komninou Ph. , Kehagias Th. , Sahonta S.‐L. , Kioseoglou J. , Vouroutzis N. , Hausler I. , Neumann W. , Iliopoulos E. , Georgakilas A. , Karakostas Th. 
Published: September 2008

AbstractThe strain distribution and defects in a graded AlN/GaN heterostructure comprising AlN layers from 3 nm up to 100 nm grown by plasma‐assisted MBE were studied using transmission electron microscopy techniques. Gradual strain relaxation was observed as well as strain partitioning between the GaN spacers and the thicker AlN layers. Elastic strain is retained even in the thicker layers of the heterostructure. Extensive introduction of threading and misfit dislocations is observed at and above the 7 nm AlN layer. The threading dislocations adopt inclined zig‐zag line directions thus contributing to the relief of alternating compressive‐tensile elastic strain across the the layers of the heterostructure. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of composition on the bonding environment of In in InAlN and InGaN epilayers
Authors: Katsikini M. , Pinakidou F. , Paloura E. C. , Komninou Ph. , Iliopoulos E. , Adikimenakis A. , Georgakilas A. , Welter E. 
Published: September 2008

AbstractWe report on the bonding environment of In in InxAl1–xN (0.07 < x < 0.25) and InyGa1–yN (0.7 < y < 1) epilayers using extended X‐ray absorption fine structure (EXAFS) spectroscopy. The EXAFS analysis reveals that the In–N distance, in both the InAlN and the InGaN ternaries, is only weakly dependent on the In content. Contrary to that, the In–cation distances (in the 2nd nearest neighbour shell) have values closer to those predicted by Vegard's law. More specifically, the distribution of the In–cation distances is bimodal with the ff In–Ga and In–Al distances being smaller than the In–In distance. The variation of the In–Ga and In–Al distances with the In content is in agreement with Vegard's law while the In–In distance deviates from the expected values for In fractions smaller than 0.7. The identified composition‐dependent variation of the In–N and In–cation distances, indicates that the alloying induced stress in InAlN and InGaN is mainly accommodated by bond angle variation rather than bond length deformation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Coincidence detection and spike regeneration in artificial neurons
Authors: Samardak A. S. , Taylor S. , Nogaret A. , Hollier G. , Austin J. , Farrer I. , Ritchie D. A. 
Published: September 2008

AbstractWe report on a monolithic semiconductor device that computes the coincidence of time delayed electrical impulses and selectively regenerates those impulses that meet within 10 μs of each other. We obtain pulse regeneration using the negative feedback of a tunnel device and demonstrate reliable pulse amplification using an external circuit. The device emulates biological neurons which detect correlations between spike trains in real time and are able to modify synaptic weights through spike timing dependent plasticity. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Micropore modification in InP
Authors: Nohavica D. , Gladkov P. , Jarchovský Z. , Zelinka J. , Komninou Ph. , Delimitis A. , Kehagias Th. , Karakostas Th. 
Published: September 2008

AbstractThe structural features and optical properties of microporous InP substrates used for epitaxial overgrowth of thin films have been investigated. Both crystalographically oriented (CO) and current line oriented (CLO) pore networks were created by electrochemical dissolution. Heat treatment of the InP pores converted them into microcavities maintaining the same crystallographic direction. The effect of phosphorus vapour pressure was proved to be crucial for the microcavity formation, since it influences the mass transport during heat treatment. Electron microscopy and photoluminescence experiments revealed the absence of significant extended defects, both after the pore and cavities formation. The capability of improved structural quality homo‐ and hetero‐epitaxial overgrown films on the porous InP, was also demonstrated. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nonlinear optical properties of Au nanoclusters encapsulated into hybrid block copolymer micelles
Authors: Iliopoulos K. , Athanasiou D. , Meristoudi A. , Vainos N. , Pispas S. , Couris S. 
Published: September 2008

AbstractIn this work, the nonlinear optical (NLO) response of suspensions of Au nanoclusters encapsulated into hybrid block copolymer micelles was investigated by using the Z‐scan technique, employing 35 ps, 532 nm laser pulses. The block copolymer used for the encapsulation of the Au nanoclusters was poly (isoprene‐b‐acrylic acid) (PI‐PAA). The real and imaginary parts of the third‐order nonlinear susceptibility χ(3) of the dispersions were determined and were both found to be of the order of 10–13 esu for Au concentration ranged between 1 to 20 mM and of positive sign. All dispersions were exhibiting strong optical limiting action. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Auger recombination in silicon nanocrystals embedded in SiO2 wide band‐gap lattice
Authors: Mahdouani M. , Bourguiga R. , Jaziri S. , Gardelis S. , Nassiopoulou A. G. 
Published: September 2008

AbstractWe calculate the ground and excited electron and hole levels in spherical Si nanocrystals (quantum dots) embedded within SiO2 in a multiband effective mass approximation. The obtained energies of electron and hole are used to estimate the Auger Recombination (AR) lifetime in Si Nanocrystals (NCs). The excited electron, excited hole and biexciton AR types are considered. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Substituent effect on NH bond dissociation enthalpies of amines and amides: A theoretical study
Authors: Kaur Damanjit , Kaur Rupinder Preet , Kohli Ruchi 
Published: September 2008

AbstractNH bond dissociation enthalpies for the substituted ammonia, amine, amides, and their thio‐ and seleno‐analogs have been studied employing ab initio and density functional methods. The orbital interactions involving lone pair of electrons on nitrogen and substituent, electrostatic interactions, spin delocalization, and hydrogen bonding are the important factors affecting the stability of the molecule and the radical. The molecule stabilization effect and radical stabilization effect have been calculated using isodesmic reactions in order to analyze the effect of substituent on the stabilization of the molecule and the radical. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Ground and low‐lying excited C2v states of FeO2—A challenge to computational methods
Authors: Grein Friedrich 
Published: September 2008

AbstractDFT (BPW91 and B3PW91), CCSD, CCSD(T), and MP2 geometry optimizations were performed on the lowest A1, A2, B1, and B2 singlet to septet states (a total of 16 states) of FeO2, using in most cases the 6‐311+G(3df) basis set. With few exceptions, the different methods led to similar geometries. The lowest state is 3B1 or 5B2, depending on the method used. The quality of the various computational methods was tested by a comparison of vertical excitation energies with corresponding high‐level MRCI values. The best agreement with MRCI was found for BPW91 and B3PW91, with average deviations of about 0.2 eV. MRCI calculations were carried to extremely low configuration selection thresholds (0.025 μh) in order to find the lowest state of FeO2. The full CI estimate (including Davidson correction and energy extrapolation to 0 μh) gave 3A1 as the lowest state, followed by 5B2 (0.03 eV) and 3B1 (0.06 eV). Both 3B1 and 3A1 have geometries and vibrational frequencies consistent with the observed IR spectrum. The calculated adiabatic electron affinity of FeO2 (from 3B1 of FeO2 to 4B2 of FeO) is 2.46 eV with CCSD(T), and 2.22 eV with BPW91, compared with the experimental value of 2.36 eV. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Position‐dependent disturbance rejection using spatial‐based adaptive feedback linearization repetitive control
Authors: Chen Cheng‐Lun , Yang Yen‐Hsiu 
Published: September 2008

AbstractIn this paper, we propose a new design of spatial‐based repetitive control for a class of rotary motion systems operating at variable speeds. The open‐loop system in spatial domain is obtained by reformulating a nonlinear time‐invariant system with respect to angular displacement. A two‐degree‐of‐freedom control structure (comprising two control modules) is then proposed to robustly stabilize the open‐loop system and improve the tracking performance. The first control module applies adaptive feedback linearization with projected parametric update and concentrates on robust stabilization of the closed‐loop system. The second control module introduces a spatial‐based repetitive controller cascaded with a loop‐shaping filter, which not only further reduces the tracking error, but also improves parametric adaptation. The overall control system is robust to model uncertainties of the system and capable of rejecting position‐dependent disturbances under varying process speeds. Stability proof for the overall system is given. A design example with simulation is provided to demonstrate the applicability of the proposed design. Copyright © 2008 John Wiley & Sons, Ltd.
Childhood traumatic experiences, dissociation and thought suppression in patients with ‘Psychosomatic’ skin diseases
Authors: Besiroglu Lutfullah , Akdeniz Necmettin , Agargun Mehmet Yucel , Calka Omer , Ozdemir Osman , Bilgili Serap Guneş 
Published: September 2008

AbstractIn this study, patients with what were considered ‘psychosomatic’ skin diseases were compared with patients with skin conditions that are thought to be ‘non‐psychosomatic’ diseases in terms of their reported history of childhood traumatic experiences, dissociative experiences and thought suppression. Ninety‐six patients with ‘psychosomatic’ skin disease were included in the study. The comparison subjects (n = 54) were patients with skin conditions believed to have a negligible psychosomatic component and the subjects without skin disease (n = 77). Subjects were administered with the Childhood Trauma Questionnaire (CTQ), the Dissociative Experiences Scale (DES) and the White Bear Suppression Inventory (WBSI). While the ‘emotional neglect’ scores of the psychosomatic' group were significantly higher than that of both ‘non‐psychosomatic’ and healthy subjects, there were no significant differences for the other subscales of the CTQ. The ‘psychosomatic’ group scored significantly higher on the DES absorption scale, DES total and WBSI scores than the other groups. Significantly more patients in the ‘psychosomatic’ group reported a stressful life event as related to the onset of skin complaints compared with the ‘non‐psychosomatic’ group. Our results suggest that the effect of subjective perception of emotional neglect, mediated by stressful life events, increases the vulnerability to psychosomatic disease. Copyright © 2008 John Wiley & Sons, Ltd.