bluuebunny/crossref_metadata_2025_split huggingface dataset:
Time asymptotics for the polyharmonic wave equation in waveguides
Authors: Lesky P. H. 
Published: January 2003

AbstractLet Ω denote an unbounded domain in ℝn having the form Ω=ℝl×D with bounded cross‐section D⊂ℝn−l, and let m∈ℕ be fixed. This article considers solutions u to the scalar wave equation ∂u(t,x) +(−Δ)mu(t,x) = f(x)e−iωt satisfying the homogeneous Dirichlet boundary condition. The asymptotic behaviour of u as t→∞ is investigated. Depending on the choice of f ,ω and Ω, two cases occur: Either u shows resonance, which means that ∣u(t,x)∣→∞ as t→∞ for almost every x ∈ Ω, or u satisfies the principle of limiting amplitude. Furthermore, the resolvent of the spatial operators and the validity of the principle of limiting absorption are studied. Copyright © 2003 John Wiley & Sons, Ltd.
Asymptotic and spectral analysis of non‐selfadjoint operators generated by a filament model with a critical value of a boundary parameter
Authors: Shubov Marianna A. 
Published: January 2003

AbstractWe consider a class of non‐selfadjoint operators generated by the equation and the boundary conditions, which govern small vibrations of an ideal filament with non‐conservative boundary conditions at one end and a heavy load at the other end. The filament has a non‐constant density and is subject to a viscous damping with a non‐constant damping coefficient. The boundary conditions contain two arbitrary complex parameters. In our previous paper (Mathematical Methods in the Applied Sciences 2001; 24(15) : 1139–1169), we have derived the asymptotic approximations for the eigenvalues and eigenfunctions of the aforementioned non‐selfadjoint operators when the boundary parameters were arbitrary complex numbers except for one specific value of one of the parameters. We call this value the critical value of the boundary parameter. It has been shown (in Mathematical Methods in the Applied Sciences 2001; 24(15) : 1139–1169) that the entire set of the eigenvalues is located in a strip parallel to the real axis. The latter property is crucial for the proof of the fact that the set of the root vectors of the operator forms a Riesz basis in the state space of the system. In the present paper, we derive the asymptotics of the spectrum exactly in the case of the critical value of the boundary parameter. We show that in this case, the asymptotics of the eigenvalues is totally different, i.e. both the imaginary and real parts of eigenvalues tend to ∞as the number of an eigenvalue increases. We will show in our next paper, that as an indirect consequence of such a behaviour of the eigenvalues, the set of the root vectors of the corresponding operator is not uniformly minimal (let alone the Riesz basis property). Copyright © 2003 John Wiley & Sons, Ltd.
A new test of non‐inferiority for anti‐infective trials
Authors: Phillips Kem F. 
Published: January 2003

AbstractThis paper describes a new statistical test of non‐inferiority in clinical trials of anti‐infective medications. The test allows the inferiority limit, delta, to vary with the underlying success rates. The test is a simple modification of the standard fixed‐delta test, and its parameters can be adjusted to yield the fixed‐delta test, a test similar to the FDA's Points‐to‐Consider procedure, or a test with nearly constant power values over a range of success rates. The test satisfies the size and power criteria for a valid statistical test. The effects on the test of lowering success rates through stringent criteria or through error are discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Non‐inferiority trials: the ‘at least as good as’ criterion
Authors: Laster Larry L. , Johnson Mary F. 
Published: January 2003

AbstractTo demonstrate in a clinical trial that a new or experimental therapy (et) is ‘at least as good as’ a standard therapy (st), a statistical test or confidence interval procedure must rule out clinical inferiority with a high probability. The term ‘at least as good as’ implies equivalent but not necessarily superior efficacy. As it is statistically impossible to demonstrate equivalence (that is, prove the null hypothesis of no difference), Blackwelder proposed a one‐sided significance test to reject the null hypothesis that standard therapy is better than experimental therapy by a clinically acceptable amount, δBW. In this paper, Blackwelder's approach is redefined in terms of the ratio of two means (RTrue=μet/μst) based on a continuous variate with higher values denoting greater improvement. The ratio‐based equivalents to Blackwelder's hypotheses will be shown. The ratio parameter has the benefit of being available as a dimensionless percentage, not tied to a specified difference in means. Thus, a study can be sized to assure, with high probability, that the experimental therapy is ‘at least’ (RLB×100) per cent ‘as effective as’ the standard therapy, where RLB is the selected lower bound on the percentage effectiveness. A practical rationale is given for defining non‐inferiority as a high fraction or percentage of the standard drug's efficacy, both in terms of statistical efficiency and medical relevance. For most typical ‘at least as good as’ applications (when RLB<RTrue ⩽1), the ratio formatted test of H0:RTrue⩽RLB is shown to be more efficient than Blackwelder's test of H0:μst ‐ μet ⩾ δBW, thereby requiring smaller sample sizes to detect the directionally based non‐null alternatives contained in H1:μet/μst>RLB or, equivalently, μst ‐ μet<δBW. Further, when RTrue= 1.0, tests of Blackwelder's hypotheses, their ratio‐based equivalents and conventional superiority can be evaluated for comparative efficiency. Testing H0:RTrue⩽RLB with single‐sided critical region of size α, versus H1:RTrue>RLB, is shown to be more efficient than excluding RLB from the lower limit of a 100(1–2α) per cent two‐sided symmetric confidence interval centred by R̂. Relevant examples will be presented. Copyright © 2003 John Wiley & Sons, Ltd.
Some fundamental issues with non‐inferiority testing in active controlled trials
Authors: James Hung H. M. , Wang Sue‐Jane , Tsong Yi , Lawrence John , O'Neil Robert T. 
Published: January 2003

AbstractIn an active controlled non‐inferiority trial without a placebo arm, it is often not entirely clear what the primary objective is. In many cases the considered goal is to demonstrate that the experimental treatment preserves at least some fraction of the effect of the active control. The active control effect is a parameter, the value of which is unknown. To test the hypothesis of effect preservation, the classical confidence interval approach requires specification of a non‐inferiority margin which is a function of the unknown active control effect. When the margin is estimated, it is also not clear what is the relevant type I error of making a false assertion about preservation of the active control effect. The statistical uncertainty of the estimated margin arguably needs to be incorporated in evaluation of the type I error. In this paper we discuss these fundamental issues. We show that the classical confidence interval approach cannot attain the target type I error exactly since this error varies as the sample size or as the values of the nuisance parameters in the active controlled trial change. In contrast, the preservation tests, as proposed in literature, can attain the target type I error rate exactly, regardless of the sample size and the values of the nuisance parameters, but can do so only at the price of several strong assumptions holding that may not be directly verifiable. One assumption is the constancy condition holding whereby the effect of the active control in the historical trial populations is assumed to carry to the population of the active control trial. When this condition is violated, both the confidence interval approach and the preservation test method may be problematic. Copyright © 2003 John Wiley & Sons, Ltd.
Rank‐based tests for non‐inferiority and equivalence hypotheses in multi‐centre clinical trials using mixed models
Authors: Rashid M.Mushfiqur 
Published: January 2003

AbstractRank‐based procedures for testing non‐inferiority and equivalence hypotheses for data (continuous) arising from multi‐centre clinical trials are developed using mixed models. The centres are presumed to be a random sample from the population of centres which might conceivably use the treatments under investigation, and the treatment effects are assumed to be fixed. It is assumed that there are no interactions between treatments and centres. Non‐inferiority and equivalence hypotheses are tested using rank (R) estimators. The R‐estimators are obtained by minimizing a combined dispersion function. The combined dispersion function is a sum of separate dispersion functions from each centre. Both the combined dispersion function and the centre‐specific dispersion functions are piecewise linear functions. As a result, the R‐estimates are expected to be less influenced by outliers. Large sample properties of the R‐estimators including efficiencies are developed. A small scale simulation study is conducted to compare the performances (empirical levels and powers) of the non‐parametric procedures and the normal theory based procedures. Published in 2003 by John Wiley & Sons, Ltd.
Decomposition of hair lichens (Alectoria Sarmentosa and Bryoria spp.) Under Snowpack in Montane Forest, Cariboo Mountains, British Columbia
Authors: Coxson Darwyn S. , Curteanu Medea 
Published: January 2003

AbstractMontane old-growth forests on the windward slopes of interior mountain ranges in British Columbia support high loadings of arboreal lichens. These lichens represent a major source of readily labile plant material and potentially play an important role in ecosystem nutrient dynamics. Given the role of winter storms in scouring lichens from within the canopy and the extended length of winter snowpack, from November through to May or even early June, in these ecosystems, the decomposition of lichen litterfall should be heavily influenced by placement within the snowpack. We have examined this factor by placing litter bags containing samples of the hair lichens, Alectoria sarmentosa and Bryoria spp., on top of the winter snowpack in the Cariboo Mountains. Samples were set out in early- (8 Nov.) mid- (16 Jan.) and late- (22 Mar.) winter and subsequently retrieved on spring snow-melt (22 May). Lichen samples that were buried in the lower snowpack all winter long (196 days) lost two-thirds of their original mass. In contrast lichens placed on the snowpack in mid- (127 days) or late-winter (61 days) lost only 6-15% of their total mass, far less than would be predicted on the basis of time in snowpack alone. Spot measurements showed that the snowpack environment effectively buffers litter samples from extreme winter conditions. All lichen samples placed within the snowpack showed much higher C/N ratios on removal, indicating rapid leaching of readily soluble cellular constituents in the snowpack environment. These findings indicate that the snowpack environment plays a major role in decomposition processes in these high-elevation forests and reinforces our view that lichens are a readily labile nutrient source within these ecosystems.
Comparison of commonly used orthopaedic outcome measures using palm‐top computers and paper surveys
Authors: Saleh Khaled J. , Radosevich David M. , Kassim Rida A. , Moussa Mohamed , Dykes Darrell , Bottolfson Helena , Gioe Terence J. , Robinson Harry 
Published: January 2003

AbstractIntroduction: Measuring patient‐perceived outcomes following orthopaedic procedures have become an important component of clinical research and patient care. General and disease‐specific outcomes measures have been developed and applied in orthopaedics to assess the patients' perceived health status. Unfortunately, paper‐based, self‐administered instruments remain inefficient for collecting data because of: (a) missing data (b) respondent error, and (c) the costs to administer and enter data.Objective: To study the comparability of palm‐top computer devices and paper‐pencil self‐administered questionnaires in the collection of health‐related quality of life (HRQL) information from patients.Methods: The comparability of administering HRQL questionnaires using palm‐top computer and traditional paper‐based forms was tested in a sample of 96 patients with complaints of hip and/or knee pain. Each patient completed mailed versions of the Medical Outcomes Study (MOS), 36‐item Health Survey (SF‐36), and Western Ontario and McMasters University Arthritis Index (WOMAC) three weeks prior to presenting to clinic. At the clinic they were asked to complete the same outcomes measures using the palm‐top computer or a paper‐and‐pencil version.Analysis: In the analysis, scale distributions, floor and ceiling effects, internal consistency and retest reliability of scales were compared across the two data collection methods. Because the baseline characteristics of the groups were not strictly comparable according to age, the data were analyzed for the entire sample and stratified according to age.Results: Few statistically significant differences were found for the means, variances and intra‐class correlation coefficients between the methods of administration. While the scale distribution between the two methods was comparable, the internal consistency of the scales was dissimilar.Conclusions: Administration of HRQL questionnaires using portable palm‐top computer devices has the potential advantage of decreased cost and convenience. These data lend some support for the comparability of palm‐top computers and paper surveys for outcomes measures widely used in the field of orthopaedic surgery. The present study identified the lack of reliability across modes of administration that requires further study in a randomized comparability trial. These mode effects are important for orthopaedic surgeons to appreciate before implementing innovative data‐capture technologies in their practices.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
The effects of blood glucose control upon fracture healing in the BB Wistar rat with diabetes mellitus
Authors: Beam Heather A. , Russell Parsons J. , Lin Sheldon S. 
Published: January 2003

AbstractSeveral clinical series, analyzing fracture healing in patients with diabetes mellitus (DM), demonstrated significant incidence of delayed union, non‐union, and pseudarthrosis. In this study, analysis was performed to evaluate the effects of blood glucose (BG) control on fracture healing in the DM BB Wistar rat, a rat strain that represents a close homology to Type I DM in man. Our study showed decreased cell proliferation at the fracture site as well as decreased mechanical stiffness and bony content in the poorly controlled DM rats. To determine the effect of BG control, DM rats were treated with insulin sufficient to maintain physiologic BG levels throughout the course of the study. Values of cellular proliferation, biomechanical properties and callus bone content in tightly controlled DM animals were not significantly different from values of non‐DM control values. This study suggests that insulin treatment with resultant improved BG control will ameliorate the impaired early and late parameters of DM fracture healing.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Apoptosis in rotator cuff tendonopathy
Authors: Yuan Jun , Murrell George A. C. , Wei Ai‐Qun , Wang Min‐Xia 
Published: January 2003

AbstractThe aim of this study was to investigate the involvement of apoptosis (programmed cell death) in the pathogenesis of rotator cuff disorders. The edges of torn supraspinatus rotator cuff tendons were collected from patients with rotator cuff tear (n = 25). Samples of the intra‐articular portion of subscapularis tendons were collected from patients without rotator cuff tear as control (n = 6). To minimize individual variance, we also collected six pairs of supraspinatus tendon and subscapularis tendon from six patients with rotator cuff tears. Apoptosis was detected by in situ DNA end labelling assay and DNA laddering assay. Immunohistochemical staining was performed to identify cells undergoing apoptosis. Control subscapularis tendon had normal morphology. Tendon from torn supraspinatus rotator cuff showed significant mucoid degeneration. Within the areas of degeneration, there were large numbers of apoptotic cells. The percentage of apoptotic cells in the degenerative rotator cuff (34%) was significantly higher than that in controls (13%) (p < 0.001). The excessive apoptosis detected in degenerative rotator cuff tissue was confirmed by DNA laddering assays. This is the first report of excessive apoptosis in degenerating rotator cuff tendon. Cells undergoing apoptosis in rotator cuff were mainly fibroblast‐like cells. These finding indicate that apoptosis may play an important role in the pathogenesis of rotator cuff degeneration.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Social phobia in the community: relationship between diagnostic threshold and prevalence
Authors: Pélissolo A. , André C. , Moutard-Martin F. , Wittchen H.U. , Lépine J.P. 
Published: January 2003

SummaryThis paper investigates the prevalence of symptoms and various diagnostic criteria of DSM-IV social phobia in a French national representative population of 12,873 subjects, aged 15 or more. Respondents filled out a mailed questionnaire based on the social phobia section of the Munich-Composite International Diagnostic Interview (M-CIDI) in the year 1996. Response rate was 80.5%.Sixty-seven point one percent of the sample acknowledge having at least once in their lifetime a strong fear of one or more of the six prototypical social fear situations that are used as the CIDI social phobia stem items. However, only a few fulfilled all DSM-IV diagnostic criteria for social phobia. Depending on the type of diagnostic algorithms used and the stringency in which these criteria are applied, the resulting prevalence varied between 1.9 and 7.3%. These findings provide some further evidence about the considerable effects of varying diagnostic criteria and thresholds on prevalence rates for social phobia, explaining why most recent surveys have reported considerably higher rates of social phobia than those in the early 1980s.
The impact of the gender composition of households on inequality and poverty: a comparison across Russia and Eastern Europe
Authors: Popova Daria 
Published: January 2003

This study compares poverty and income distribution among gender subgroups in Russia and four East European countries—Bulgaria, Romania, Hungary and Poland—in 2000. Does the gender poverty gap exist in these countries and if yes, how big is it? How much does the level of gender inequality contribute to explaining the level of aggregate inequality and poverty within each country? To what extent may the differences emerging in cross-country comparisons of poverty and inequality be explained by differences in the gender composition of households, e.g., the prevalence of female-dominated households? These are the questions I seek to answer in this paper.
Equivalent expenditure is adopted as a measure of economic welfare of households with different gender ratios. The gender gap is defined as the degree of distance between the economic welfare of households dominated by women and households dominated by men. Headcount poverty and average poverty shortfalls are calculated using relative poverty lines. Inequality is measured by Gini and Theil L coefficients.
Anomalous effect of anthracene‐9‐carboxylic acid on calcium‐activated chloride currents in rabbit pulmonary artery smooth muscle cells
Authors: Piper Angela S , Greenwood Iain A 
Published: January 2003

Ca2+‐activated Cl− currents (ICl(Ca)) evoked by K+‐free pipette solutions containing 500 nM Ca2+ were recorded in rabbit pulmonary artery smooth muscle cells. A voltage step protocol in which the cells were stepped to +70 mV and then to −80 mV produced outward and inward Cl− currents respectively that exhibited distinctive voltage‐ and time‐dependent kinetics that remained consistent for the recording period.
Application of the Cl− channel inhibitor anthracene‐9‐carboxylic acid (A‐9‐C, 500 μM), produced a small inhibition of the maximum outward Cl− current at +70 mV (21±10%) but augmented the amplitude of the instantaneous inward relaxation at −80 mV by 321±34% (n=12).
The current recorded in the absence and presence of A‐9‐C reversed at the theoretical Cl− equilibrium potential and the reversal potential was shifted by about −40 mV upon replacement of external chloride ion by the more permeant anion thiocyanate. Currents in the absence and presence of A‐9‐C were similarly affected by 100 μM niflumic acid.
Augmentation of the inward current at −80 mV by A‐9‐C required prior depolarization, i.e. A‐9‐C did not simply activate a Cl− current at negative membrane potentials. Moreover the degree of augmentation was independent of the internal Ca2+ for concentrations between 100 nM and 1 μM Ca2+.
The data from the present study confirm previous observations that the inhibitory effect of Cl− channel blockers is modified when [Ca2+]i is maintained at higher than normal resting concentrations.

British Journal of Pharmacology (2003) 138, 31–38. doi:10.1038/sj.bjp.0705000
Nitric oxide enhances substance P‐induced itch‐associated responses in mice
Authors: Andoh Tsugunobu , Kuraishi Yasushi 
Published: January 2003

Substance P (SP) elicits itch and itch‐associated responses in humans and mice, respectively. In mice, NK1 tachykinin receptors are involved in SP‐induced itch‐associated responses, scratching, and mast cells do not play a critical role. The present study was conducted to elucidate the role of nitric oxide (NO) on SP‐induced scratching in mice.
An intradermal injection of SP (100 nmol site−1) elicited scratching in mice, and it was suppressed by an intravenous injection of the NO synthase (NOS) inhibitor NG‐nitro‐L‐arginine methyl ester (L‐NAME), but not by its inactive enantiomer D‐NAME. Intradermal injections of L‐NAME (100 nmol site−1), another NOS inhibitor 7‐nitroindazole (10 nmol site−1) and the NO scavenger haemoglobin (0.01–10 nmol site−1) also inhibited SP‐induced scratching.
L‐NAME (100 nmol site−1) did not affect scratching induced by an intradermal injection of 5‐hydroxytryptamine (100 nmol site−1).
Intradermal injections of L‐arginine (300 nmol site−1) and the NO donor (±)‐(E)‐4‐ethyl‐2‐[(E)‐hydroxyimino]‐5‐nitro‐3‐hexenamide (NOR3; 100 nmol site−1) increased scratching induced by SP. Intradermal injections of L‐arginine (1–1000 nmol site−1) or NOR3 (1–100 nmol site−1) alone were without effects on scratching.
Intradermal injections of SP (10–100 nmol site−1) increased the intradermal concentration of NO in a dose‐dependent manner in mice. An increase in NO levels induced by SP was inhibited by L‐NAME and the NK1 tachykinin receptor antagonist L‐668,169, but not by the NK2 tachykinin receptor antagonist L‐659,877.
SP (1–10 μM) elicited NO production in cultured human keratinocytes and the SP‐induced NO production was inhibited by L‐NAME and L‐668,169.
We conclude that intradermal SP increases NO in the skin, possibly through the action on NK1 tachykinin receptors on the epidermal keratinocytes and that NO enhances SP‐induced itch‐associated responses.

British Journal of Pharmacology (2003) 138, 202–208. doi:10.1038/sj.bjp.0705004