bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental studies of stability and transition
in high-speed wakes
Authors: LYSENKO V. I. 
Published: July 2002

The investigation undertaken deals with the development of disturbances in a supersonic
wake (free viscous layer and regular wake) behind a flat plate both in its linear
and nonlinear stages. The influence of a number of factors (Mach and Reynolds
numbers, temperature factor, thickness of the plate, length of its stern) on the wake
stability and transition was studied. The development of the artificial disturbances in
a wake at Mach number M∞ = 2 was investigated also.It was found that compressibility of the flow (increasing Mach number) stabilizes
the wake disturbances – their amplification rates decrease, and the transition point
moves away from the model plate. Cooling of the model surface at
M∞ ≈ 7 has a
destabilizing influence on the development of disturbances in the wake. With increase
of unit Reynolds number the beginning of transition in the wake moves forward to
a rear critical point. It was confirmed that a distinctive maximum in the spectral
distribution of fluctuations appears, corresponding to Strouhal number (based on
frequency of this maximum) of 0.3. With the growth of the model thickness the
disturbance amplification rates in the wake increase, which results in earlier transition
of a laminar wake into turbulent one. With the growth of length of the plate stern,
the position of the wake transition moves back accordingly, while the wake stability
increases a little (though very unsignificantly). In the nonlinear stage of development
of disturbances, the occurrence of a triad of waves, satisfying the resonant correlation
of frequencies, and the growth of harmonics are observed. A monochromatic packet
of waves of Tollmien–Schlichting type, rather narrow (in the transversal coordinate)
in the boundary layers on a flat plate with an opposite wedge at the stern, was found
to extend in the wake. The wake disturbances have a complex wave structure. At
the Mach number of free flow 2.0, the three-dimensional disturbances are the most
unstable in the wake.
Optimal LES formulations for isotropic turbulence
Authors: LANGFORD JACOB A. , MOSER ROBERT D. 
Published: July 2002

It is shown that there is an abstract subgrid model that is in all senses ideal. An
LES using the ideal subgrid model will exactly reproduce all single-time, multi-point
statistics, and at the same time will have minimum possible error in instantaneous
dynamics. The ideal model is written as an average over the real turbulent fields
whose large scales match the current LES field. But this conditional average cannot
be computed directly. Rather, the ideal model is the target for approximation when
developing practical models, though no new practical models are presented here. To
construct such models, the conditional average can be formally approximated using
stochastic estimation. These optimal formulations are presented, and it is shown that a
relatively simple but general class of one-point estimates can be computed from two-point correlation data, and that the estimates retain some of the statistical properties
of the ideal model.To investigate the nature of these models, optimal formulations were applied to
forced isotropic turbulence. A variety of optimal models of increasing complexity were
computed. In all cases, it was found that the errors between the real and estimated
subgrid force were nearly as large as the subgrid force itself. It is suggested that
this may also be characteristic of the ideal model in isotropic turbulence. If this is
the case, then it explains why subgrid models produce reasonable results in actual
LES while performing poorly in a priori tests. Despite the large errors in the optimal
models, one feature of the subgrid interaction that is exactly represented is the energy
transfer to the subgrid scales by each wavenumber.
Dynamical properties of forced shear layers in an annular geometry
Authors: BERGERON K. , COUTSIAS E. A. , LYNOV J. P. , NIELSEN A. H. 
Published: July 2002

Results of numerical simulations of a forced shear flow in an annular geometry
are presented. The particular geometry used in this work reduces the effects of
centrifugal and Coriolis forces. However, there are still a large number of system
parameters (shear width, shear profile, radius of curvature, initial conditions, etc.)
to characterize. This set of variables is limited after the code has been validated
with experimental results (Rabaud & Couder 1983; Chomaz et al. 1988) and with
the associated linear stability analysis. As part of the linear stability characterization,
the pseudo-spectrum for the associated Orr–Sommerfeld operator for plane, circular
Couette flow is calculated, and it is found to be insensitive to perturbations.The numerical simulation code is a highly accurate de-aliased spectral method which
utilizes banded operators to increase the computational efficiency. Viscous dissipation
terms enter the code directly from the equations of motion. The results from the
simulation code at low Reynolds numbers are compared with the results from linear
stability analysis and are used to give predictions for the coefficients of the Landau
equation describing the saturation behaviour near the critical Reynolds number.
Numerical results at higher Reynolds numbers demonstrate the effects of spin-up and
spin-down, including the experimentally observed hysteresis. The properties of two-
dimensional shears at high Reynolds numbers, at which temporal states are formed,
are also addressed.
The endostyle and the feeding filter in salps (Tunicata)
Authors: Bone Q. , Carre C. , Ryan K.P. 
Published: July 2002

This note examines the way the pharyngeal feeding filter is constructed within the salp endostyle. Three salp species (Pegea confoederata, Thalia democratica and Salpa fusiformis) have been examined: results from each are essentially similar. The endostyle is a deep ventral groove in the pharynx, divided by a line of long basal cilia. These are flanked by gland cells which secrete the ‘mucus” which forms one of the sets of filaments of the filter. Beside the openings of this basal row of gland cells (marked by bumps of curious ‘mucus’ rodlets), there is a fence of two adjacent rows of cilia. The first of these two rows, (nearest the basal mid-line), whose tips lie next to the rodlet bumps, are regularly spaced 1.0 μm apart along the endostyle, whilst the cilia of the second row are at around half this spacing. Passing upwards in the endostylar groove, this first ciliary fence is followed by a ciliated zone, and then a second row of glandular cells is linked to a second ciliary fence with a single row of cilia only.Filaments derived from the first set of gland cells pass obliquely over the ciliated zone, and continue over the second ciliary fence. The cilia of the second fence are often surrounded by very striking borders or curtains of rodlets which appear to dissolve, run down the cilia and pass off the tips as filaments, when they are joined by the first set of filaments to form a net with an elongate rhomboidal mesh. As this passes upwards, the mesh changes to become more or less square by the time it comes to overlie a striking asymmetrical band of cilia arranged in columns, when it is now composed of two sets of filaments running vertically and horizontally, spaced some 1.3 μm apart.Various aspects of the formation of this filter net are considered.
Seasonal variations of total mercury in foliar tissues of Posidonia oceanica
Authors: Capiomont Anne , Piazzi Luigi , Pergent Gérard 
Published: July 2002

Cold vapour atomic absorption spectrophotometry (CV-AAS) was used to evaluate total mercury concentrations in Posidonia oceanica, after initial mineralization of the samples in a microwave oven. Measurements were taken of three leaf tissue types: the adult leaf blade, the adult leaf sheath, and the intermediate leaf blade. Plants were sampled monthly over a one year period at two sites presenting different degrees of pollution: Rosignano (Tuscany, Italy) and Tonnara (Corsica, France).The mercury concentrations recorded in the different P. oceanica tissues were systematically higher at the more contaminated of the two sites, thus confirming the value of this plant as a biological indicator. The mercury concentrations observed exhibit seasonal variations, with higher concentrations recorded in winter than in summer. These variations seemed to be negatively correlated to the plant's phenology. Also, the mean mercury concentrations were generally lower in young tissue (intermediate leaf blade) than in the older tissue (adult leaf blade).
Verbal fluency in patients with schizophrenia and affective psychoses and their first-degree relatives
Authors: GILVARRY C. M. , RUSSELL A. , JONES P. , SHAM P. , HEMSLEY D. , MURRAY R. M. 
Published: July 2002

Background. Schizophrenic patients are known to have neuropsychological deficits including impaired verbal fluency, but it is not clear whether this latter deficit is: (a) a consequence of overall intellectual deficit; (b) shared with affective psychotic patients; or (c) shared by the relatives of schizophrenic patients; and (d) shared by the relatives of affective psychotic patients.Methods. We administered Thurstone's Verbal Fluency Test to 45 schizophrenic patients and 72 of their relatives, and 30 affective psychotic patients and 53 of their relatives. Subjects were asked to generate as many words as possible beginning with the letters ‘C’ and ‘S’ and the total was taken as the dependent variable. Subjects also completed the National Adult Reading Test (NART) to provide a measure of (pre-morbid) IQ.Results. Schizophrenic patients generated significantly fewer words than affective psychotic patients, however adjusting for NART this became non-significant. Schizophrenic (but not affective psychotic) patients generated significantly fewer words than their relatives; again adjusting for NART this became non-significant. Patients who had been exposed to obstetric complications (OC+) and those who had not (OC−) had similarly poor verbal fluency scores. Relatives of OC+ schizophrenic patients had superior verbal fluency than relatives of OC− schizophrenic patients and this remained significant after adjustment for NART.Conclusions. The results suggest that some families transmit impairment in verbal fluency as part of a pattern of lower overall IQ. However, in other families, relatives show largely normal neuropsychological function, and the poorer verbal performance of the schizophrenic member appears to have arisen secondary to his/her exposure to OCs.
Puberty and depression: the roles of age, pubertal

status and pubertal timing
Authors: ANGOLD A. , COSTELLO E. J. , WORTHMAN C. M. 
Published: July 2002

Background. Previous work has indicated that the

2[ratio ]1 female[ratio ]male sex ratio in unipolar depressive

disorders does not emerge until some time between ages 10 and 15.Methods. Data from four annual waves of data collection from

the Great Smoky Mountains Study

(GSMS) involving children aged nine to 16 were employed.Results. Pubertal status better predicted the emergence of

the expected sex ratio than did age. Only

after the transition to mid-puberty (Tanner Stage III and above) were

girls more likely than boys

to be depressed. The timing of this transition had no effect on

depression rates. Before Tanner Stage

III, boys had higher rates of depression than girls, and the prevalence

of depression appeared to fall

in boys at an earlier pubertal stage than that at which it began to

rise in girls. In addition, recent

transition to Tanner Stage III or higher had a transient effect in

reducing the prevalence of depression in boys.Conclusions. The period of emergence of increased risk for

depression in adolescent girls appears to

be a relatively sharply demarcated developmental transition occurring

in mid-puberty. Previously

reported effects of the timing of puberty (which have tended to

be transient) appeared less important

in increase of risk for depression than pubertal status.
Patient treatment insistence and medication craving
in long-term low-dosage benzodiazepine prescriptions
Authors: LINDEN M. , BÄR T. , GEISELMANN B. 
Published: July 2002

Background. Long-term low-dosage dependence on benzodiazepines

is traditionally explained by
withdrawal symptoms. Previous research has not given much attention
to reports that suggest that
many patients oppose stopping benzodiazepines long before withdrawal symptoms
have developed.
This study investigates the scope of and factors associated with this pre-withdrawal
treatment
insistence.Methods. Patients receiving long-term low-dosage benzodiazepines

in primary care were asked to
take a drug-holiday of at least 3 weeks. Sociodemographic, medication,

morbidity and attitudinal
variables were assessed in addition to the GPs' perceptions of their
patients.Results. Two-thirds of the patients rejected the drug-holiday

proposal. Patients who refused a drug-holiday were less educated and
were using a higher percentage of long-acting benzodiazepines than
patients who accepted the drug-holiday proposal. Those who refused were
seen by their GPs as
being more complaining, harder to satisfy and less co-operative.Conclusions. These results provide evidence for drug-seeking

or craving behaviour of patients who
receive low-dosage benzodiazepine prescriptions. A major problem in benzodiazepine
withdrawal
occurs before the withdrawal programme has even begun. These data show
that benzodiazepine
low-dosage dependence should be considered a real form of dependence.
The association of sexual and physical abuse with
somatization: characteristics of patients presenting
with irritable bowel syndrome and non-epileptic
attack disorder
Authors: REILLY J. , BAKER G. A. , RHODES J. , SALMON P. 
Published: July 2002

Background. Physical symptoms are commonly presented for
treatment in the absence of physical
pathology. This study tests predictions arising from the theory that childhood
sexual abuse leads
to emotional distress, illness orientation and social dysfunction as adults
and that one or more of
these effects, in turn, leads to presentation of functional (i.e. unexplained)
symptoms.Methods. Two groups of patients with physical symptoms in the
absence of organic disease
(non-epileptic attack disorder or irritable bowel syndrome) were contrasted
with organically diseased
groups with comparable symptoms (epilepsy and Crohn's disease, respectively).Results. Despite their contrasting clinical presentation, irritable
bowel and non-epileptic attack
groups were similar in recalling more sexual and physical abuse, as both
children and adults, than
their comparison groups. They were also similar in being more emotionally
and socially disturbed
and illness-orientated, but these putative mediating variables could not
account for the relationship
of abuse with presentation of functional symptoms.Conclusions. Adults presenting functional neurological and
abdominal symptoms are characterized
by history of abuse. The current focus on childhood sexual abuse should
be broadened to include
sexual, and particularly physical, abuse in adulthood as well as childhood.
The intervening
processes that link abuse to somatization remain to be identified but are
unlikely to include adult
emotional and social disturbance or general illness-orientation.
Emotional suppression: can it predict cancer outcome in women with suspicious screening
mammograms?
Authors: O'DONNELL M. C. , FISHER R. , IRVINE K. , RICKARD M. , McCONAGHY N. 
Published: July 2002

Background. Previous studies have implicated emotional suppression, in particular suppression of anger, in the onset and progression of breast cancer. Many of these studies used non-standardized measures and failed to control for the effects of age and/or possible knowledge of diagnosis. The present study aimed to avoid these methodological errors in investigating the relationship of emotional suppression to a diagnosis of breast cancer in a large mammography screened population.Method. Data were collected from 1151 women with suspicious mammograms recalled
to a breast screening programme. Prior to multidisciplinary assessment women were asked to complete the Courtauld Emotional Control Scale. Imaging assessment outcome data and biopsy results were collected.Results. Fifteen per cent of this population subsequently were diagnosed with breast cancer. There were no significant associations between a cancer outcome and emotional suppression before or after the highly significant effect of age was taken into account.Conclusions. These results suggest that suppression of emotion may not be relevant to the development of breast cancer. Its role in the progression of existing disease requires clarification.
Obstetric complications predict treatment response in
first-episode schizophrenia
Authors: ALVIR J. M. J. , WOERNER M. G. , GUNDUZ H. , DEGREEF G. , LIEBERMAN J. A. 
Published: July 2002

Background. Understanding the role of obstetric complications (OCs) in schizophrenia could
potentially shed light on the heterogeneity in the aetiology and course of schizophrenia. Many
investigators have reported an association between OCs and schizophrenia, but few have examined
the association between OCs and treatment outcome. We investigated this question in a sample of
patients studied during their first episode of schizophrenia, schizoaffective or schizophreniform
disorder.Method. OC histories were obtained for 59 patients participating in the Hillside First Episode Study.
Cox proportional hazards regression analysis was used to estimate the effect of OCs on treatment
response during the first episode of schizophrenia.Results. Twelve of the 59 patients (20%) had positive histories of OCs. This group exhibited lower
rates of treatment response than those with negative OC histories (hazard ratio controlling for sex
= 0·28; 95% CI = 0·13, 0·62). The positive OC group also had significantly greater lateral ventricle
volume, baseline disorganization and number of live births. The effect of OC history on treatment
response held when these three variables were controlled for.Conclusion. A history of obstetric complications predicted poor response to treatment in the first
episode of schizophrenia. This large effect was based on a small sample of 59 patients. Thus,
replication is called for.
Relatives' expressed emotion (EE) and PTSD
treatment outcome
Authors: TARRIER N. , SOMMERFIELD C. , PILGRIM H. 
Published: July 2002

Background. Expressed emotion (EE) is a measure that has been used to assess the quality of the
relationship between patient and their key relative. It has been shown to be strongly predictive of
clinical outcome in a range of psychiatric and medical disorders. This study investigated the effect
of EE on treatment outcome in chronic post-traumatic stress disorder (PTSD).Methods. A prospective design was adopted. The key relatives of 31 PTSD patients participating
in a treatment trial comparing imaginal exposure with cognitive therapy were interviewed and rated
on EE prior to treatment allocation. The effect of EE on post-treatment clinical outcomes was
assessed.Results. Sixteen patients (52%) had high EE and 15 (48%) low EE relatives. Patients with high EE
relatives showed lesser change scores on the main outcome variable of the trial, the total CAPS
score, and on all the secondary outcome variables than those with low EE relatives. Using different
multiple regression models the EE scales of criticism and hostility predicted just under 20% of the
outcome variance. These two scales were highly correlated and criticism marginally predicted the
greatest variance (19·7%).Conclusions. The results highlight the importance of the quality of the patient's social environment
in influencing their response to cognitive and behavioural treatments.
NMR spectroscopy: a multifaceted approach to macromolecular structure
Authors: Ferentz Ann E. , Wagner Gerhard 
Published: July 2002

1. Introduction 292. Landmarks in NMR of macromolecules 322.1 Protein structures and methods development 322.1.1 Sequential assignment method 322.1.2 Triple-resonance experiments 342.1.3 Structures of large proteins 362.2 Protein–nucleic acid complexes 372.3 RNA structures 382.4 Membrane-bound systems 393. NMR spectroscopy today 403.1 State-of-the-art structure determination 413.2 New methods 443.2.1 Residual dipolar couplings 443.2.2 Direct detection of hydrogen bonds 443.2.3 Spin labeling 453.2.4 Segmental labeling 463.3 Protein complexes 473.4 Mobility studies 503.5 Determination of time-dependent structures 523.6 Drug discovery 534. The future of NMR 544.1 The ease of structure determination 544.2 The ease of making recombinant protein 554.3 Post-translationally modified proteins 554.4 Approaches to large and/or membrane-bound proteins 564.5 NMR in structural genomics 564.6 Synergy of NMR and crystallography in protein structure determination 565. Conclusion 576. Acknowledgements 577. References 57Since the publication of the first complete solution structure of a protein in 1985 (Williamson
et al. 1985), tremendous technological advances have brought nuclear magnetic resonance
spectroscopy to the forefront of structural biology. Innovations in magnet design, electronics,
pulse sequences, data analysis, and computational methods have combined to make NMR an
extremely powerful technique for studying biological macromolecules at atomic resolution
(Clore & Gronenborn, 1998). Most recently, new labeling and pulse techniques have been
developed that push the fundamental line-width limit for resolution in NMR spectroscopy,
making it possible to obtain high-field spectra with better resolution than ever before (Dötsch
& Wagner, 1998). These methods are facilitating the study of systems of ever-increasing
complexity and molecular weight.
REM sleep deprivation: The wrong paradigm leading to wrong conclusions
Authors: Born Jan , Gais Steffen 
Published: July 2002

There are obvious flaws in REM sleep suppression paradigms that do not allow any conclusion to be drawn either pro or contra the REM sleep-memory hypothesis. However, less intrusive investigations of REM sleep suggest that this sleep stage or its adjunct neuroendocrine characteristics exert a facilitating influence on certain aspects of ongoing memory formation during sleep.[Nielsen; Vertes & Eastman]
A TOOL TO IMPROVE QUALITY OF REPORTING PUBLISHED ECONOMIC ANALYSES
Authors: Gerard Karen , Seymour Janelle , Smoker Irenie 
Published: July 2002

Objectives: To test the feasibility of obtaining a baseline level
of quality of reporting for cost-utility analysis (CUA) studies using the
British Medical Journal economic submissions checklist, test
interrater reliability of this tool, and discuss its longer term implications.Methods: CUA studies in peer-reviewed English language journals in
1996, assessed using the British Medical Journal checklist, a quality
index, and interrater reliability correlations.Results: Forty-three CUA studies were assessed, with 23 checklist
items acceptable and 10 items inadequate. Lowest quality scores were reported
in specialist medical journals. Proportional agreement between assessors was
over 80%.Conclusions: The British Medical Journal checklist is a
feasible tool to collect baseline information on the quality of reporting in
journals other than the British Medical Journal. Editors of
specialist medical journals are in greatest need of economic guidance. If
handled carefully, they might consider adopting the British Medical
Journal checklist.