bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tikhonov regularization of large symmetric problems
Authors: Calvetti D. , Reichel L. , Shuibi A. 
Published: September 2004

AbstractMany popular solution methods for large discrete ill‐posed problems are based on Tikhonov regularization and compute a partial Lanczos bidiagonalization of the matrix. The computational effort required by these methods is not reduced significantly when the matrix of the discrete ill‐posed problem, rather than being a general nonsymmetric matrix, is symmetric and possibly indefinite. This paper describes new methods, based on partial Lanczos tridiagonalization of the matrix, that exploit symmetry. Computed examples illustrate that one of these methods can require significantly less computational work than available structure‐ignoring schemes. Copyright © 2004 John Wiley & Sons, Ltd.
Stewart's pivoted QLP decomposition for low‐rank matrices
Authors: Huckaby D. A. , Chan T. F. 
Published: September 2004

AbstractThe pivoted QLP decomposition, introduced by Stewart, represents the first two steps in an algorithm which approximates the SVD. If A is an m‐by‐n matrix, the matrix A∏0 is first factored as A∏0 = QR, and then the matrix RT∏1 is factored as RT∏1 = PLT, resulting in A = Q∏1LPT∏, with Q and P orthogonal, L lower‐triangular, and ∏0 and ∏1 permutation matrices. The Q and P matrices provide approximations of the left and right singular subspaces, and the diagonal elements of L are excellent approximations of the singular values of A. Stewart observed that pivoting is not necessary in the second step, allowing one to efficiently truncate the decomposition, computing only the first few columns of R and L and choosing the stopping point dynamically. In this paper, we demonstrate that this truncating actually works by extending our theory for the complete pivoted QLP decomposition (UCLA CAM Report # 02‐29, 2002). In particular, say there is a gap between σk and σk+1, and partition the matrix L into diagonal blocks L11 and L22 and off‐diagonal block L21, where L11 is k‐by‐k. If we compute only the block L11, the convergence of (σj(L11)−1 − σ)/σ for j = 1,…,k are all quadratic in the gap ratio σk+1/σk. Hence, if the gap ratio is small, as it usually is when A has numerical rank k (independent of m and n), then all of the singular values are likely to be well approximated. This truncated pivoted QLP decomposition can be computed in 𝒪(mnk) time, making it ideal for accurate SVD approximations of low‐rank matrices. Copyright © 2004 John Wiley & Sons, Ltd.
Linear eigenvalue analysis of the disc‐brake squeal problem
Authors: Cao Q. , Ouyang H. , Friswell M. I. , Mottershead J. E. 
Published: September 2004

AbstractThis paper presents a numerical method to calculate the unstable frequencies of a car disc brake and suggests a suitable analysis procedure. The stationary components of the disc brake are modelled using finite elements and the disc as a thin plate. The separate treatments of the stationary components and the rotating disc facilitate the modelling of the disc brake squeal as a moving load problem. Some uncertain system parameters of the stationary components and the disc are tuned to fit experimental results. A linear, complex‐valued, asymmetric eigenvalue formulation is derived for the friction‐induced vibration of the disc brake. Predicted unstable frequencies are compared with experimentally established squeal frequencies of a real car disc brake. Copyright © 2004 John Wiley & Sons, Ltd.
A method for multiple crack growth in brittle materials without remeshing
Authors: Budyn É. , Zi G. , Moës N. , Belytschko T. 
Published: September 2004

AbstractA method for modelling the growth of multiple cracks in linear elastic media is presented. Both homogeneous and inhomogeneous materials are considered. The method uses the extended finite element method for arbitrary discontinuities and does not require remeshing as the cracks grow; the method also treats the junction of cracks. The crack geometries are arbitrary with respect to the mesh and are described by vector level sets. The overall response of the structure is obtained until complete failure. A stability analysis of competitive cracks tips is performed. The method is applied to bodies in plane strain or plane stress and to unit cells with 2–10 growing cracks (although the method does not limit the number of cracks). It is shown to be efficient and accurate for crack coalescence and percolation problems. Copyright © 2004 John Wiley & Sons, Ltd.
Smoothing with positivity‐preserving Padé schemes for parabolic problems with nonsmooth data
Authors: Wade B. A. , Khaliq A. Q. M. , Siddique M. , Yousuf M. 
Published: September 2004

AbstractWe introduce a new class of higher order numerical schemes for parabolic partial differential equations that are more robust than the well‐known Rannacher schemes. The new family of algorithms utilizes diagonal Padé schemes combined with positivity‐preserving Padé schemes instead of first subdiagonal Padé schemes. We utilize a partial fraction decomposition to address problems with accuracy and computational efficiency in solving the higher order methods and to implement the algorithms in parallel. Optimal order convergence for nonsmooth data is proved for the case of a self‐adjoint operator in Hilbert space as well as in Banach space for the general case. Numerical experiments support the theorems, including examples in pricing options with nonsmooth payoff in financial mathematics. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005
Providing psychosocial support for breast cancer patients based on screening for distress within a consultation‐liaison service
Authors: Söllner Wolfgang , Maislinger Susanne , König Alexandra , DeVries Alexander , Lukas Peter 
Published: September 2004

AbstractIn a consecutive sample of 100 breast cancer patients undergoing radiotherapy, cancer‐related distress was assessed with the Hospital Anxiety and Depression Scale and patients' interest in and acceptance of psychosocial support with the Questionnaire for Psychosocial Support and the European Consultation Liaison Workgroup documentation form. 31% of the patients suffered moderate to severe anxiety and/or depression and 42% expressed interest in supportive counselling. The wish for psychosocial support did not correlate with distress (moderate or severe anxiety and/or depression; Kappa = 0.06; P = 0.560). Patients with elevated levels of distress and/or those expressing a wish for psychosocial support were offered counselling by a psychotherapist and a social worker within the framework of a liaison service; 69% of the 58 patients offered such support accepted it. We conclude that screening instruments are helpful in identifying and consequently offering support to patients in need of counselling. Copyright © 2004 John Wiley & Sons, Ltd.
Vorsicht Hochspannung!: Risikomanagement in Energiemärkten (Teil III) Fortgeschrittene Spotpreismodelle und VaR‐Ansätze
Authors: Rachev Svetlozar (Zari) 
Published: September 2004

AbstractIm ersten Teil der Serie [siehe RISKNEWS 03/2004] wurde eine kurze Einführung in den Stromhandel in Deutschland gegeben. Weiterhin wurden Besonderheiten im Preisverhalten auf Strommärkten erläutert. Der zweite Teil [siehe RISKNEWS 04/2004] beschäftigte sich mit der Modellierung von Strompreisen, insbesondere der Berücksichtigung von Saisonalitäten sowie der stochastischen Modellierung der Preisprozesse. Der dritte Teil der Serie erläutert verfeinerte Methoden der Preismodellierung sowie Ansätze des Risikomanagements in Energiemärkten mit Hilfe des Value‐at‐Risk und RAROC‐Konzepts.
Health related quality of life of adolescents in Vietnam: cross‐cultural adaptation and validation of the Adolescent Duke Health Profile
Authors: Thi Xuan Hanh Vo , Guillemin Francis , Dinh Cong Duong , Parkerson George R. , Bach Thu Pham , Tu Quynh Pham , Briançon Serge 
Published: September 2004

AbstractQuality of life (QOL) of adolescents has been scarcely documented in a general population sample. The study was aimed at translating and adapting the Adolescent Duke Health Profile to Vietnamese, validating the questionnaire, determining reference value, and identifying determinants of poor QOL.Following a cross‐cultural methodology, the Adolescent Duke Health Profile (ADHP) had content adapted to Vietnamese by alteration of 2 out of 17 items. Test–retest validity was checked in 408 adolescents. Construct validity and internal consistency were assessed in a 1408 probability sample of adolescents in Vietnam, and determinants were analysed by multiple linear regression.The ADHP showed satisfactory internal consistency (Cronbach's α=0.87–0.92) and satisfactory construct validity in relation with drug abuse or not, or with parent situation living in couple or alone. Test–retest reliability was acceptable (ICC=0.7–0.8) and major determinants were age, sex, education, chronic disease, alcohol and drug use.This works provide a validated, simple health related QOL scale suited to adolescent population with reference values. Taking into account determinants identified will help program prevention and intervention health policy and to evaluate the effect of these actions.
Expression and regulation of interleukin‐23 subunits in human peripheral blood mononuclear cells and hematopoietic cell lines in response to various inducers
Authors: Ma Xiao‐Tong , Zhang Xiu‐Jun , Zhang Bin , Geng Yi‐Qi , Lin Yong‐Min , Li Ge , Wu Ke‐Fu 
Published: September 2004

AbstractIL‐23 is a novel cytokine composed of an IL‐12 p40 and a p19 subunit. We analyzed human peripheral blood mononuclear cells (PBMC) and hematopoietic cell lines for constitutive expression of IL‐23 and IL‐12 subunits and expression following exposure to various stimuli, and investigated the mechanisms of their induction by LPS and SAC. IL‐23 p19 and IL‐12 p35 mRNAs were expressed in fresh PBMC, and expression of all IL‐23 and IL‐12 subunits was up‐regulated by LPS and SAC. LPS‐induced increase of IL‐23 and IL‐12 subunits expression was CD14‐dependent, while CD14 was not involved in SAC‐induced p19 transcription. Both LPS‐ and SAC‐induced subunits expression required p38 MAPK pathway. PHA effected an increase of p19 mRNA in both CD4+ and CD8+ T cells, whereas p35 was minimally regulated by PHA. IFN‐γ primed monocytes for LPS stimulation of p19, p35 and p40 expression. p19 mRNA was detectable in most hematopoietic cell lines tested but p35 distribution was more restricted. A phorbol diester enhanced p19, p35 and p40 expression in EBV‐positive cell lines. Our results suggest that both the subunits of IL‐23 are tightly regulated; the expression pattern and regulation mode of IL‐23 p19 is similar to as well as distinct from that of IL‐12 p35.
Which is better for cDNA-microarray-based classification: ratios or direct intensities
Authors: Attoor Sanju , Dougherty Edward R. , Chen Yidong , Bittner Michael L. , Trent Jeffrey M. 
Published: September 2004

Abstract
Motivation: There are two general methods for making gene-expression microarrays: one is to hybridize a single test set of labeled targets to the probe, and measure the background-subtracted intensity at each probe site; the other is to hybridize both a test and a reference set of differentially labeled targets to a single detector array, and measure the ratio of the background-subtracted intensities at each probe site. Which method is better depends on the variability in the cell system and the random factors resulting from the microarray technology. It also depends on the purpose for which the microarray is being used. Classification is a fundamental application and it is the one considered here.
Results: This paper describes a model-based simulation paradigm that compares the classification accuracy provided by these methods over a variety of noise types and presents the results of a study modeled on noise typical of cDNA microarray data. The model consists of four parts: (1) the measurement equation for genes in the reference state; (2) the measurement equation for genes in the test state; (3) the ratio and normalization procedure for a dual-channel system; and (4) the intensity and normalization procedure for a single-channel system. In the reference state, the mean intensities are modeled as a shifted exponential distribution, and the intensity for a particular gene is modeled via a normal distribution, Normal(I, αI), about its mean intensity I, with α being the coefficient of variation of the cell system. In the test state, some genes have their intensities up-regulated by a random factor. The model includes a number of random factors affecting intensity measurement: deposition gain d, labeling gain, and post-image-processing residual noise. The key conclusion resulting from the study is that the coefficient of variation governing the randomness of the intensities and the deposition gain are the most important factors for determining whether a single-channel or dual-channel system provides superior classification, and the decision region in the α−d plane is approximately linear.
Supplementary information: A companion website containing supplementary and background material can be accessed at http://ee.tamu.edu/~edward/ratio_intensity/
CIS: compound importance sampling method for protein–DNA binding site p-value estimation
Authors: Barash Y. , Elidan G. , Kaplan T. , Friedman N. 
Published: September 2004

Abstract
Motivation: A key aspect of transcriptional regulation is the binding of transcription factors to sequence-specific binding sites that allow them to modulate the expression of nearby genes. Given models of such binding sites, one can scan regulatory regions for putative binding sites and construct a genome-wide regulatory network. In such genome-wide scans, it is crucial to control the amount of false positive predictions. Recently, several works demonstrated the benefits of modeling dependencies between positions within the binding site. Yet, computing the statistical significance of putative binding sites in this scenario remains a challenge.
Results: We present a general, accurate and efficient method for computing p-values of putative binding sites that is applicable to a large class of probabilistic binding site and background models. We demonstrate the accuracy of the method on synthetic and real-life data.
Availability: The procedure for scanning DNA sequences and computing the statistical significance of putative binding site scores is available upon request at http://compbio.cs.huji.ac.il/CIS/
Contact: nir@cs.huji.ac.il
Seq2Struct: a resource for establishing sequence-structure links
Authors: Via Allegra , Zanzoni Andreas , Helmer-Citterich Manuela 
Published: September 2004

Abstract
Summary: Several methods for establishing cross-links between Protein Data Bank (PDB) structures or Structural Classification of Proteins (SCOP) domains and Swiss-Prot + TrEMBL sequences (or vice versa) rely on database annotations. Alternatively, sequence alignment procedures can be used. In this study, we describe Seq2Struct, a web resource for the identification of sequence-structure links. The resource consists of an exhaustive collection of annotated links between Swiss-Prot + TrEMBL and PDB + SCOP database entries. Links are based on pre-established highly reliable thresholds and stored in a relational database, which has been enhanced using annotations derived from Swiss-Prot, PDB, SCOP, GOA and DSSP databases. The Seq2Struct database contents, supported by a WWW web interface, can be queried both online and downloaded.
Availability: The Seq2Struct resource, with related documentation, is available at http://surface.bio.uniroma2.it/seq2struct/
Contact: seq2struct@cbm.bio.uniroma2.it
arrayMagic: two-colour cDNA microarray quality control and preprocessing
Authors: Buness Andreas , Huber Wolfgang , Steiner Klaus , Sültmann Holger , Poustka Annemarie 
Published: September 2004

Abstract
Summary: arrayMagic is a software package for quality control and preprocessing of two-colour cDNA microarray data. The automated analysis pipeline comprises data import, normalization, replica merging, quality diagnostics and data export. The script-based processing combines reproducibility and flexibility at high-throughput and provides quality-assured and preprocessed microarray data to high-level follow-up analysis.
Availability: The R package arrayMagic is available with BSD license at http://www.bioconductor.org
Contact: a.buness@dkfz.de
Supplementary information: The package contains documentation in the form of manual pages and a vignette with a guided tour of a typical workflow.
Isobolographic and Subthreshold Analysis of Interactions among Felbamate and Four Conventional Antiepileptic Drugs in Pentylenetetrazole‐induced Seizures in Mice
Authors: Borowicz Kinga K. , Luszczki Jarogniew J. , Czuczwar Stanislaw J. 
Published: September 2004

Summary:  Purpose: Despite possibility of idiosyncratic reaction development, felbamate (FBM) is recommended in Lennox–Gastaut syndrome and partial refractory epilepsy. The aim of this study was to evaluate the profile of interactions between FBM and four conventional antiepileptic drugs (AEDs): clonazepam (CZP), ethosuximide (ESM), phenobarbital (PB), and valproate (VPA), in pentylenetetrazole (PTZ)‐induced convulsions in mice, a model of myoclonic seizures in humans. Methods: Data obtained from PTZ‐evoked seizures were compared by use of two basic procedures, the subthreshold method and isobolographic analysis. Results of the chimney test (evaluating motor coordination) also were elaborated isobolographically. Thus it was possible to determine both median toxic dose (TD50) and protective index (PI) for each drug combination. Results: FBM reduced the clonic seizure activity [with an ED50 of 9.7 mg/kg; TD50, 439.1 mg/kg; and PI, 45.3]. FBM at the dose of 10 mg/kg, but not 7.5 mg/kg, significantly reduced PTZ‐induced convulsions in mice. In the subthreshold method, FBM (7.5 mg/kg) did not affect the protective activity of conventional AEDs used in the study. However, when applied at 10 mg/kg, it enhanced the protective activity of PB and ESM, but not that of VPA or CZP. The nature of these interactions could not be precisely estimated with this method. The exact profile of drug interactions was determined with the use of isobolography. In terms of seizure inhibition, antagonism was found between FBM and VPA applied at the fixed‐dose ratio of 3:1. Synergy was detected between FBM and PB (1:3). Combinations of FBM with VPA (1:3, 1:1), PB (1:1, 3:1), and ESM or CZP (1:3, 1:1, 3:1) led to additive interactions. As regards motor impairment, the combinations of FBM with VPA (1:3) or CZP (1:1, 3:1) were synergistic. Remaining combinations exhibited pure additivity. Pharmacokinetic events may influence FBM/ESM and FBM/CZP interactions, because FBM lowered the brain concentration of ESM and increased that of CZP. Conclusions: The profitable benefit index was found only for the combination of FBM with PB (1:3). Conversely, the combinations of FBM with either VPA (1:3) or CZP (1:1, 3:1) do not seem promising for the therapy of refractory myoclonic convulsions. Isobolographic analysis provides more reliable clues to be considered by the clinicians willing to introduce AED combinations for the therapy of epilepsy.
Selective Antiepileptic Effects ofN‐Palmitoylethanolamide, a Putative Endocannabinoid
Authors: Sheerin Aaron H. , Zhang Xia , Saucier Deborah M. , Corcoran Michael E. 
Published: September 2004

Summary: Purpose:The purpose of this study was to determine whetherN‐palmitoylethanolamide (PEA), a putative endocannabinoid, would be effective against kindled amygdaloid seizures. For a comparison with earlier work, we also tested the effectiveness of PEA against pentylenetetrazol (PTZ)‐induced convulsions.Methods:Kindling electrodes were implanted bilaterally in the amygdala in 32 Long‐Evans rats. After the kindling of generalized (stage 5) seizures, the effects of PEA administration [i.p.; 1, 10, 100 mg/kg in dimethylsulfoxide (DMSO)] were evaluated for anticonvulsant activity. PEA (40 mg/kg, i.p. in DMSO) also was tested for anticonvulsant activity against PTZ‐induced convulsions (75 mg/kg, i.p.).Results:After i.p. administration of PEA, kindled rats displayed an increased latency to clonus at the 1‐mg/kg dose. No other dose‐dependent effects were noted. When tested against PTZ‐induced convulsions, PEA protected against tonic convulsions and prolonged the latency between convulsive episodes.Conclusions:PEA produces antiepileptic effects, but does not completely suppress seizures. The mechanism of action of PEA remains to be defined.
Successful Management of Intractable Epilepsy with Lidocaine Tapes and Continuous Subcutaneous Lidocaine Infusion
Authors: Mori Kenji , Ito Hiromichi , Toda Yoshihiro , Hashimoto Toshiaki , Miyazaki Masahito , Saijo Takahiko , Kuroda Yasuhiro 
Published: September 2004

Summary:  Purpose: We report the successful management of a 10‐year‐old girl with intractable frontal lobe epilepsy by using lidocaine tapes and continuous subcutaneous lidocaine infusion. Methods: This patient's seizures were refractory to conventional antiepileptic drugs (AEDs) and mexiletine, but they responded well to the intravenous infusion of lidocaine. The intravenous infusion of lidocaine was replaced by lidocaine tape therapy, and subsequently by continuous subcutaneous lidocaine infusion therapy. The lidocaine tape (Penles, Nihon Lederle, Tokyo Japan) used was a stamp‐sized (30.5 × 50.0 mm) tape containing 18 mg of lidocaine. We used 25 lidocaine tapes every 12 h (50 tapes/day). Lidocaine hydrochloride (10%) was administered continuously at a dose of 1.5 mg/kg/h (0.3 ml/hour) through a 27‐G needle that was inserted in the subcutaneous tissue. Results: Lidocaine tape therapy showed good efficacy for 1 year. After that, six lidocaine tapes were added 6 h after the exchange of 25 lidocaine tapes [62 tapes/day (25,6,25,6)], because the seizures became frequent when the lidocaine tapes were being exchanged. The seizures were then well controlled, but dermatitis due to the lidocaine tapes grew serious, and lidocaine tape therapy had to be stopped. Continuous subcutaneous infusion of lidocaine applied in place of lidocaine tapes provided long‐term seizure control without remarkable side effects. Conclusions: Lidocaine tape therapy and continuous subcutaneous lidocaine infusion therapy were considered to be useful for controlling this patient's seizures. This is the first report to describe the efficacy of continuous subcutaneous lidocaine infusion therapy for epilepsy.