bluuebunny/crossref_metadata_2025_split huggingface dataset:
On ‘spurious’ eddies
Authors: Drikakis D. , Margolin L. G , Smolarkiewicz P.K. 
Published: October 2002

AbstractRecently, several papers have appeared in the CFD literature, proposing an idealized instability problem as a benchmark for discriminating among numerical algorithms for two‐dimensional Navier–Stokes flows. The problem is a double shear layer simulated at coarse resolution and with a prescribed interface perturbation. A variety of second‐order accurate schemes have been tested, with all results falling into one of two solution patterns—one pattern with two eddies and the other with three eddies. In the literature, there is no fast‐and‐firm rule to predict the results of any particular algorithm. However, it is asserted that the two‐eddy solution is correct. Our own research has led to two conclusions. First, the appearance of the third eddy is tied up with small details of the truncation error; we illustrate this point by prescribing small changes that lead to reversal of the appearance/disappearance of the third eddy in several schemes. Second, we discuss the realizability of the two solutions and suggest that the three‐eddy solution is the more physical. Overall, we conclude that this problem is a poor choice of benchmark to discriminate among numerical algorithms. Copyright © 2002 John Wiley & Sons, Ltd.
The harmonic adjoint approach to unsteady turbomachinery design
Authors: Duta M. C. , Giles M. B. , Campobasso M. S. 
Published: October 2002

AbstractIn recent years, there has been rapid progress in aerodynamic optimization methods which use adjoint flow analysis to efficiently calculate the sensitivity of steady‐state objective functions to changes in the underlying design variables. This paper shows that the same adjoint approach can be used in turbomachinery applications in which the primary concern is blade vibration due to harmonic flow unsteadiness.The paper introduces the key engineering concepts and discusses the derivation of the adjoint analysis at the algebraic level. The emphasis is on the algorithmic aspects of the analysis, on the iterative solution method and on the role played by the strong solid wall boundary condition, in particular. The novel ideas are exploited to reveal the potential of the approach in the minimization of the unsteady vibration of turbomachinery blades due to incident wakes. Copyright © 2002 John Wiley & Sons, Ltd.
Schur complement preconditioners for the Navier–Stokes equations
Authors: Loghin D. , Wathen A. J. 
Published: October 2002

AbstractMixed finite element formulations of fluid flow problems lead to large systems of equations of saddle‐point type for which iterative solution methods are mandatory for reasons of efficiency. A successful approach in the design of solution methods takes into account the structure of the problem; in particular, it is well‐known that an efficient solution can be obtained if the associated Schur complement problem can be solved efficiently and robustly. In this work we present a preconditioner for the Schur complement for the Oseen problem which was introduced in Kay and Loghin (Technical Report 99/06, Oxford University Computing Laboratory, 1999). We show that the spectrum of the preconditioned system is independent of the mesh parameter; moreover, we demonstrate that the number of GMRES iterations grows like the square‐root of the Reynolds number. We also present convergence results for the Schur complement of the Jacobian matrix for the Navier–Stokes operator which exhibit the same mesh independence property and similar growth with the Reynolds number. Copyright © 2002 John Wiley & Sons, Ltd.
Global kinetic energy conservation with unstructured meshes
Authors: Benhamadouche S. , Laurence D. 
Published: October 2002

AbstractConserving kinetic energy is essential in Large Eddy Simulation (LES) in order that subgrid scale modelling (SGS) is not hidden by numerical errors. High‐order schemes, which are not available for unstructured grids, are sufficient but not a necessary condition for energy conservation. The problem addressed here is directly ensuring energy conservation through a careful discretization of the momentum and mass equations, and it is shown that this can be achieved with a low‐order scheme for unstructured grids. Copyright © 2002 John Wiley & Sons, Ltd.
Hybrid wavelet collocation–Brinkman penalization method for complex geometry flows
Authors: Vasilyev O. V. , Kevlahan N. K.‐R. 
Published: October 2002

AbstractThis paper introduces the hybrid wavelet collocation–Brinkman penalization method for solving the Navier–Stokes equations in arbitrarily complex geometries. The main advantages of the wavelet collocation method and penalization techniques are described, and a brief summary of their implementation is given. The hybrid method is then applied to a simple flow around cylinders with both periodic and non‐periodic boundary conditions with Reynolds numbers in the range from 100 to 10 000 and the results are discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Finite‐volume methods for non‐linear elasticity in heterogeneous media
Authors: LeVeque Randall J. 
Published: October 2002

AbstractAn approximate Riemann solver is developed for the equations of non‐linear elasticity in a heterogeneous medium, where each grid cell has an associated density and stress–strain relation. The non‐linear flux function is spatially varying and a wave decomposition of the flux difference across a cell interface is used to approximate the wave structure of the Riemann solution. This solver is used in conjunction with a high‐resolution finite‐volume method using the CLAWPACK software. As a test problem, elastic waves in a periodic layered medium are studied. Dispersive effects from the heterogeneity, combined with the non‐linearity, lead to solitary wave solutions that are well captured by the numerical method. Copyright © 2002 John Wiley & Sons, Ltd.
The use of classical Lax–Friedrichs Riemann solvers with discontinuous Galerkin methods
Authors: Rider W. J. , Lowrie R. B. 
Published: October 2002

AbstractWhile conducting a von Neumann stability analysis of discontinuous Galerkin methods we discovered that the classic Lax–Friedrichs Riemann solver is unstable for all time‐step sizes. We describe a simple modification of the Riemann solver's dissipation returns the method to stability. Furthermore, the method has a smaller truncation error than the corresponding method with an upwind flux for the RK2‐DG(1) method. These results are verified upon testing. Copyright © 2002 John Wiley & Sons, Ltd.
DNA array‐based method for detection of large rearrangements in the BRCA1 gene
Authors: Frolov Andrey , Prowse Amanda H. , Vanderveer Lisa , Bove Betsy , Wu Hong , Godwin Andrew K. 
Published: October 2002

AbstractIn most families with multiple cases of breast and ovarian cancer, the cancer appears to be associated with germline alterations in BRCA1 or BRCA2. However, somatic mutations in BRCA1 and BRCA2 in sporadic breast and ovarian tumors are rare, even though loss of heterozygosity in BRCA1 and BRCA2 loci in these tumors appears frequently. This may be attributed to mutation detection assays that detect alterations in the coding regions and splice site junctions, but that miss large gene rearrangements. To look specifically for mutations such as large gene rearrangements that span several kilobases (kb) of genomic DNA, we have developed a fluorescence DNA microarray assay. This assay rapidly and simultaneously screens for such rearrangements along the entire gene. In our screen of 15 malignant ovarian tumors, we found one sample with a novel 3‐kb deletion encompassing exon 17 of BRCA1 that leads to a frameshift mutation. This deletion was not detected in the corresponding constitutive DNA. Our results indicate that, whereas somatic mutations in BRCA1 appear to be rare in ovarian cancers, the search for large gene rearrangements should be included in any BRCA1 mutational analysis. Furthermore, the method described in this report has the potential to screen clinical tumor samples for genomic rearrangements simultaneously in a large number of cancer‐associated genes. © 2002 Wiley‐Liss, Inc.
TGF‐β induces cell death in the oligodendroglial cell line OLI‐neu
Authors: Schuster Norbert , Bender Herdis , Philippi Anja , Subramaniam Srinivasa , Strelau Jens , Wang Ziyuan , Krieglstein Kerstin 
Published: October 2002

AbstractWe have shown that TGF‐β plays an important role during the period of developmental cell death in the nervous system. Immunoneutralization of TGF‐β prevents ontogenetic neuron death in vivo. Like neurons, oligodendrocytes are generated in excess and eliminated by apoptosis. It has been shown that oligodendrocyte progenitors and newly formed oligodendrocytes are especially susceptible to apoptosis. We choose the oligodendrocyte precursor cell line OLI‐neu to address the question if TGF‐β could play a role for the control of oligodendrocyte proliferation and cell death. Flow cytometric analysis revealed that OLI‐neu cells arrested in the G1 phase of the cell cycle underwent apoptosis in response to TGF‐β. TUNEL assays, apoptosis ELISA, and caspase assays substantiated the finding that OLI‐neu cells died after TGF‐β treatment. Cell death could be inhibited by application of pan‐caspase or caspase 8 and 9 inhibitors, whereas the inhibition of calpain was unaffected. Furthermore, we found a reduction of bcl‐XL at the protein as well as at the mRNA level, while p27 was upregulated. The Smad cascade was activated while TGF‐β reduced the activity of the p42/p44 MAP kinase pathway. Together, these data show that TGF‐β induced apoptotic cell death in cells of oligodendroglial origin, whereby the signaling cascade involved the downregulation of antiapoptotic signaling such as bcl‐XL leading to the activation of caspases. GLIA 40:95–108, 2002. © 2002 Wiley‐Liss, Inc.
Optimal use of markers for cobalamin and folate status in a psychogeriatric population
Authors: Nilsson Karin , Gustafson Lars , Hultberg Björn 
Published: October 2002

AbstractBackgroundCobalamin/folate deficiency is common in elderly subjects and may lead to psychiatric symptoms, but even more often it increases the severity of other organic and non‐organic mental diseases. It is therefore of importance to evaluate the optimal use of different markers of cobalamin/folate status in a psychogeriatric population.MethodsWe measured serum cobalamin, blood folate, plasma homocysteine (tHcy) and serum methylmalonic acid (MMA) in 475 well‐defined psychogeriatric patients.ResultsThe findings in the present study showed that many (41%) of the patients with normal levels of serum MMA (<0.41 μmol/l) had pathological values of at least one of the other markers for cobalamin/folate status, whereas only 17% of patients with normal plasma tHcy (<19.9 μmol/l) had pathological levels of other markers. If patients with decreased levels of serum cobalamin and/or blood folate were also excluded from these patients, only nine patients with slightly elevated levels of serum MMA remained. In the present study different upper reference limits were also tested for both serum MMA and plasma tHcy. However, the use of these limits did not cause any diagnostic improvement in the evaluation of cobalamin–folate status. Plasma tHcy was increased in almost all diagnosis groups of the psychogeriatric patients, whereas serum MMA was increased in only some groups. The distribution of the two common polymorphisms of the methylenetetrahydrofolate reductase gene (C677T and A1298C) was similar in patients with elevated and normal plasma tHcy.ConclusionsThe findings in the present study suggest the use of plasma tHcy, serum cobalamin and blood folate to evaluate cobalamin–folate status in psychogeriatric patients and to omit the use of serum MMA. Copyright © 2002 John Wiley & Sons, Ltd.
A survey of the views of geriatric psychiatrists in the United Kingdom on the use of electroconvulsive therapy to treat physically ill people
Authors: Benbow S. M. , Shah A. 
Published: October 2002

AbstractBackgroundOne of the main concerns about ECT is its use for people with concurrent medical illnesses. Geriatric psychiatrists are more often likely to encounter this situation in working with older age groups. Drawing on the collective experience of all UK geriatric psychiatrists may allow a better understanding of the use of ECT for people with major medical illness.MethodsA postal questionnaire was used to seek the views of all consultant geriatric psychiatrists in the UK on the use of ECT in the presence of major illness. The questionnaire was developed from previous literature on the subject, a previous pilot study, published guidelines and clinical experience of the authors.ResultsGeriatric psychiatrists most often favour bilateral ECT. They are likely to carry out physical examination, chest X‐ray, ECG, haemoglobin estimation, urea and electrolytes, thyroid and liver function tests in medically ill people before considering ECT. They are more likely to change their ECT assessment procedures when dealing with medical illness, rather than any other aspect of treatment, and are unlikely to change any aspect of ECT treatment in someone of advanced age.ConclusionsGeriatric psychiatrists see their roles in relation to ECT as primarily that of assessment, and rely on others to advise on anaesthetic drug use, treatment technique, concurrent drug treatment and post‐ECT management. It is important that the ECT consultant and ECT anaesthetist are aware of their role and prepared to offer appropriate advice. The role of the ECT consultant in relation to the responsible medical officer requires clarification. Copyright © 2002 John Wiley & Sons, Ltd.
Eyeblink‐related areas in human cerebellum as shown by fMRI
Authors: Dimitrova Albena , Weber Johannes , Maschke Matthias , Elles Hans‐Gerd , Kolb Florian P. , Forsting Michael , Diener Hans‐Christoph , Timmann Dagmar 
Published: October 2002

AbstractClassical eyeblink conditioning is used frequently to study the role of the cerebellum in associative learning. To understand the mechanisms involved in learning, the neural circuits that generate the eyeblink response should be identified. The goal of the present study was to examine cerebellar regions that are likely to control the human eyeblink response using event‐related functional magnetic resonance imaging (fMRI). In 14 healthy volunteers eyeblinks were evoked by unilateral air‐puff stimulation (total of 30 stimuli, inter‐trial interval 27–44 sec). With eyes closed throughout the experiment, eyeblinks were recorded using a video‐based system with infrared reflecting markers being attached to the upper eyelids. From each subject 500 scans were taken (TR = 2.2 sec, 22 slices per scan, slice thickness = 3 mm) using an echo planar imaging sequence (EPI). The statistical parametric maps of the experimental volume images were estimated with SPM99 specifying an appropriate event‐related design matrix. Two main regions of significant activation were found in the ipsilateral posterior lobe of the cerebellar hemisphere. In the more anterior region the maxima of activation were located in hemispheral lobules VI and Crus I, and in the more posterior region in hemispheral lobules VIIb, Crus II and VIIIa (nomenclature according to Schmahmann et al. [2000]: MRI Atlas of the Human Cerebellum). Although less pronounced, activity was found also in corresponding areas of the contralateral cerebellar hemisphere. These eyeblink‐related areas agree with trigeminal projection areas and blink reflex control areas shown in previous animal studies. Hum. Brain Mapping 17:100–115, 2002. © 2002 Wiley‐Liss, Inc.
Revealed preference valuation compared to contingent valuation: radon‐induced lung cancer prevention
Authors: Kennedy Christine A. 
Published: October 2002

AbstractThis paper explores and compares two tools of economic valuation, revealed preference and contingent valuation, with the purpose of ultimately informing the use of two methods of economic evaluation, CEA and CBA. The valuation methods are applied to empirical data for radon‐induced lung cancer prevention. However, only the single bound CV and the subjective revealed preference estimates have overlapping confidence intervals, indicating that they do have external validity as assessed by convergent validity. The revealed preference subjective risk valuation was (£180 (£144, £247)) and the single bounded contingent valuation estimate was (£269 (£201, £343)). Copyright © 2002 John Wiley & Sons, Ltd.
Do competition and managed care improve quality?
Authors: Sari Nazmi 
Published: October 2002

AbstractIn recent years, the US health care industry has experienced a rapid growth of managed care, formation of networks, and an integration of hospitals. This paper provides new insights about the quality consequences of this dynamic in US hospital markets. I empirically investigate the impact of managed care and hospital competition on quality using in‐hospital complications as quality measures. I use random and fixed effects, and instrumental variable fixed effect models using hospital panel data from up to 16 states in the 1992–1997 period. The paper has two important findings: First, higher managed care penetration increases the quality, when inappropriate utilization, wound infections and adverse/iatrogenic complications are used as quality indicators. For other complication categories, coefficient estimates are statistically insignificant. These findings do not support the straightforward view that increases in managed care penetration are associated with decreases in quality. Second, both higher hospital market share and market concentration are associated with lower quality of care. Hospital mergers have undesirable quality consequences. Appropriate antitrust policies towards mergers should consider not only price and cost but also quality impacts. Copyright © 2002 John Wiley & Sons, Ltd.
Free tissue transfer and local flap complications in anterior and anterolateral skull base surgery
Authors: Heth Jason A. , Funk Gerry F. , Karnell Lucy H. , McCulloch Timothy M. , Traynelis Vincent C. , Nerad Jeffrey A. , Smith Russell B. , Graham Scott M. , Hoffman Henry T. 
Published: October 2002

AbstractBackgroundAdvances in reconstructive techniques over the past two decades have allowed the resection of more extensive skull base tumors than had previously been possible. Despite this progress, complications related to these cases remain a concern.MethodsUnivariate and multivariate analyses were used to determine the relationship of host, tumor, defect, treatment, and reconstructive variables to wound and systemic complications after anterior and anterolateral skull base resections. The study included 67 patients receiving local flap (LF) or free tissue transfer (FTT) reconstructions during an 8‐year period.ResultsOverall, 28% of patients had a major wound complication, and 19% had a major systemic complication. LF and FTT flaps had similar rates of wound complications. LF reconstructions were associated with late wound breakdown problems, and FTT flap complications were primarily acute surgery–related problems.ConclusionsThe surgical reconstruction of skull base defects should be planned on the basis of the ability of the technique to attain safe closure and maintain integrity after radiation therapy. © 2002 Wiley Periodicals, Inc. Head Neck 24: 00–00, 2002
An exploratory investigation of learning culture theory and employee participation in decision making
Authors: Thompson Margaret A. , Kahnweiler William M. 
Published: October 2002

AbstractSchein's theory (1992) implies that in an organization with a

“learning culture” employees must participate in decision‐making activities. This study

explores the proposition that there is a relationship between employee participation in decision making and

organizational learning culture (OLC). Qualitative data were used to rate four organizations on the

characteristics of OLC, and quantitative data on participation in decision making were collected from

ninety‐seven rank‐and‐file employees across these four organizations. Results of a regression

analysis did not strongly support this proposal, indicating that there is not a significant predictive value of

participation in decision making on OLC. Suggestions for future research in light of this finding are offered.
Immunotoxicity of acute acephate exposure in control or IL‐1‐challenged rats: correlation between the immune cell composition and corticosteroid concentration in blood
Authors: Singh Ashok K. , Jiang Yin 
Published: October 2002

AbstractCorticosterone concentration and the immune cell composition were measured in rats exposed by intraperitoneal (i.p.) injection to different doses (10–500 mg kg−1) of acephate (Ace) and 250 µg kg−1 of interleukin 1 (IL‐1), either alone or in combination. Two different combination protocols were used: IL‐1 and Ace were administered simultaneously; and IL‐1 was injected 60 min after Ace administration (sequential exposure). Ace, in a dose‐ and time‐dependent manner, inhibited blood and brain acetylcholinesterase (AChE) activities, increased blood corticosterone concentrations, suppressed blood CD4, CD8, B cell and monocyte contents and increased blood neutrophil counts. The Ace‐induced changes lasted for up to 24 h after Ace exposure. Interleukin 1 increased blood corticosterone concentrations without affecting blood or brain AChE activities. The IL‐1‐induced corticosterone concentration returned to the basal level within 3–10 h after IL‐1 exposure. The CD4, CD8, B cell and monocyte counts increased significantly at 10 min after IL‐1 exposure. The cell counts decreased gradually thereafter and returned to the basal level within 30 min after IL‐1 exposure. Simultaneous exposure of rats to Ace and IL‐1 partially suppressed the IL‐1‐induced increase in the immune cell counts and decreased the immune cell numbers below the basal values. Sequential injection of Ace and IL‐1 blocked the IL‐1‐induced increase in the immune cell numbers. Thus, Ace exposure would impair the normal distribution of immune cells and deregulate the IL‐1 response in rats. This study therefore suggests that Ace would suppress the immune cell numbers in blood, thus decreasing an organism's immunity. Ace exposure occurring concurrent with injury would augment the acute‐phase response, which would augment the toxic effects of IL‐1 and other cytokines, and Ace exposure occurring prior to the injury would suppress or abolish the initial stimulatory effects of IL‐1, which would decrease an organism's ability to combat infection or injury. Copyright © 2002 John Wiley & Sons, Ltd.