bluuebunny/crossref_metadata_2025_split huggingface dataset:
An ‘ideal’ form of decaying two-dimensional turbulence
Authors: IWAYAMA TAKAHIRO , SHEPHERD THEODORE G. , WATANABE TAKESHI 
Published: July 2002

In decaying two-dimensional Navier–Stokes turbulence, Batchelor's similarity
hypothesis fails due to the existence of coherent vortices. However, it is shown that
decaying two-dimensional turbulence governed by the Charney–Hasegawa–Mima (CHM)
equation(∂/∂t)(∇2φ−λ2φ)
+J(φ, ∇2φ) = D,where D is a damping, is described well by Batchelor's similarity hypothesis for wave
numbers k [Lt ] λ (the so-called AM regime). It is argued that CHM turbulence in the
AM regime is a more ‘ideal’ form of two-dimensional turbulence than is Navier–Stokes
turbulence itself.
Direct numerical simulation of turbulent flow over a

backward-facing step
Authors: LE HUNG , MOIN PARVIZ , KIM JOHN 
Published: July 2002

Turbulent flow over a backward-facing step is studied by

direct numerical solution of the Navier–Stokes equations. The

simulation was conducted at a Reynolds number of 5100 based on the

step height h and inlet free-stream velocity, and an

expansion ratio of 1.20. Temporal behaviour of spanwise-averaged

pressure fluctuation contours and reattachment length show evidence

of an approximate periodic behaviour of the free shear layer with a

Strouhal number of 0.06. The instantaneous velocity fields indicate

that the reattachment location varies in the spanwise direction, and

oscillates about a mean value of 6.28h. Statistical results

show excellent agreement with experimental data by Jovic & Driver

(1994). Of interest are two observations not previously reported for

the backward-facing step flow: (a) at the relatively low

Reynolds number considered, large negative skin friction is seen in

the recirculation region; the peak

|Cf| is about 2.5 times

the value measured in experiments at high Reynolds numbers;

(b) the velocity profiles in the recovery region fall below

the universal log-law. The deviation of the velocity profile from the

log-law indicates that the turbulent boundary layer is not fully

recovered at 20 step heights behind the separation.The budgets of all Reynolds stress components have been computed.

The turbulent kinetic energy budget in the recirculation region is

similar to that of a turbulent mixing layer. The turbulent transport

term makes a significant contribution to the budget and the peak

dissipation is about 60% of the peak production. The

velocity–pressure gradient correlation and viscous diffusion

are negligible in the shear layer, but both are significant in the

near-wall region. This trend is seen throughout the recirculation and

reattachment region. In the recovery region, the budgets show that

effects of the free shear layer are still present.
The instability of the shear layer separating from

a bluff body
Authors: PRASAD ANIL , WILLIAMSON CHARLES H. K. 
Published: July 2002

Notwithstanding the fact that the instability of the separated
shear

layer in the

cylinder wake has been extensively studied, there remains some

uncertainty regarding not only the critical Reynolds number at which

the instability manifests itself, but also the variation of its

characteristic frequency with Reynolds number (Re). A large

disparity exists in the literature in the precise value of the critical

Reynolds number,

with quoted values ranging from Re = 350 to Re = 3000.

In the present paper, we demonstrate that the spanwise end conditions

which control the primary mode of vortex shedding significantly affect

the shear-layer instability. For parallel shedding conditions, shear-layer

instability manifests itself at Re ≈ 1200, whereas for

oblique shedding conditions it is inhibited until a significantly

higher Re ≈ 2600, implying that even in the absence of a

variation in free-stream turbulence level, the oblique angle of primary

vortex shedding influences the onset of shear-layer instability, and

contributes to the large disparity in quoted values of the critical

Reynolds number. We confirm the existence of intermittency in

shear-layer fluctuations and show that it is not related to the

transverse motion of the shear layers past a fixed probe, as suggested

previously. Such fluctuations are due to an intermittent streamwise

movement of the transition point, or the location at which fluctuations

develop rapidly in the shear layer.Following the original suggestion of Bloor (1964), it has generally

been assumed in previous studies that the shear-layer frequency

(normalized by the primary vortex shedding frequency) scales with

Re1/2, although a careful examination of the

actual data points from these studies does not support such a

variation. We have reanalysed all of the actual data points from

previous investigations and include our own measurements, to find

that none of these studies yields a relationship which is

close to Re1/2. A least-squares analysis which

includes all of the previously available data produces a variation

of the form Re0·67. Based on simple physical

arguments that account for the variation of the characteristic

velocity and length scales of the shear layer, we predict a variation

for the normalized shear-layer frequency of the form

Re0·7, which is in good agreement with the

experimental measurements.
The onset of thermal convection in a rapidly rotating sphere
Authors: JONES CHRIS A. , SOWARD ANDREW M. , MUSSA ALI I. 
Published: July 2002

The linear stability of convection in a rapidly rotating sphere studied here builds
on well established relationships between local and global theories appropriate to
the small Ekman number limit. Soward (1977) showed that a disturbance marginal
on local theory necessarily decays with time due to the process of phase mixing
(where the spatial gradient of the frequency is non-zero). By implication, the local
critical Rayleigh number is smaller than the true global value by an O(1) amount. The
complementary view that the local marginal mode cannot be embedded in a consistent
spatial WKBJ solution was expressed by Yano (1992). He explained that the criterion
for the onset of global instability is found by extending the solution onto the complex
s-plane, where s is the distance from the rotation axis, and locating the double turning
point at which phase mixing occurs. He implemented the global criterion on a related
two-parameter family of models, which includes the spherical convection problem for
particular O(1) values of his parameters. Since he used one of them as the basis of a
small-parameter expansion, his results are necessarily approximate for our problem.Here the asymptotic theory for the sphere is developed along lines parallel to Yano
and hinges on the construction of a dispersion relation. Whereas Yano's relation is
algebraic as a consequence of his approximations, ours is given by the solution of a
second-order ODE, in which the axial coordinate z is the independent variable. Our
main goal is the determination of the leading-order value of the critical Rayleigh
number together with its first-order correction for various values of the Prandtl
number.Numerical solutions of the relevant PDEs have also been found, for values of
the Ekman number down to 10−6; these are in good agreement with the
asymptotic theory. The results are also compared with those of Yano, which are
surprisingly good in view of their approximate nature.
Hamiltonian theory of guiding-centre motion in an electric field with
strong gradient
Authors: DIRICKX M. , WEYSSOW B. 
Published: July 2002

The guiding-centre equations of motion of a classical charged particle
in a
strong magnetic field and a strongly sheared electric field are derived.
They can
be used to analyse the dynamics of particles in electromagnetic fields
whose
spatial profiles are similar to those observed during the H mode in the
DIII-D
tokamak, for instance. The derivation of the equations of motion is performed

up to second order in the drift parameter by applying a Hamiltonian
pseudocanonical transformation that removes the gyrophase induced by the

magnetic field. The main difference with the standard case of a slowly
varying
electric field relates to the variation of the new gyrophase and to the
expression
for the magnetic moment: mv2⊥/2B

must be replaced byformula hereThe latter case is also reconsidered – mainly to reveal the consequences
of the
removal of a hidden divergence for small parallel velocities resulting
from the
usual averaging transformation.
Multiculturalism and the Possibility of Transcultural Educational and Philosophical Ideals
Authors: Siegel Harvey 
Published: July 2002

How should we think about the interrelationships that obtain among Philosophy, Education, and Culture? In this paper I explore the contours of one such interrelationship: namely, the way in which educational and (other) philosophical ideals transcend individual cultures. I do so by considering the contemporary educational and philosophical commitment to multiculturalism. Consideration of multiculturalism, I argue, reveals important aspects of the character of both educational and philosophical ideals.Specifically, I advance the following claims:i) We are obliged to embrace the moral and political directives of multiculturalism.ii) This obligation is a moral one: that is, multiculturalism is justified on moral grounds.iii) Far from entailing any philosophically problematic form of cultural relativism, multiculturalism is itself a ‘universal’ or ‘transcultural’ ideal.iv) Moreover, the advocacy of multiculturalism presupposes another kind of universality, dubbed below ‘transcultural normative reach.’v) Consequently, multiculturalism should not be understood as entailing the demise of ‘universalistic’ dimensions of either philosophy or education.
A deficit in attentional set-shifting of violent offenders
Authors: BERGVALL Å. H. , WESSELY H. , FORSMAN A. , HANSEN S. 
Published: July 2002

Background. Recent brain imaging studies suggest that proneness to violence and antisocial behaviour may be associated with dysfunction of the prefrontal cortex. The present study, therefore, examined aspects of prefrontally guided executive functions in a group of criminal violent men.Methods. Violent offenders undergoing forensic psychiatric examination by court order undertook computerized tasks for planning, visual working memory and attentional set-shifting from the Cambridge Neuropsychological Test Automated Battery. Their performance was compared to that of subjects with marginal mental retardation and normal controls.Results. Violent offenders performed well on tasks for spatial and figurative working memory, as well as on a test for planning. A marked impairment was observed in the attentional set-shifting task: offenders made significantly more errors than the other groups when required to shift attention from one perceptual dimension to another. Reversal learning was also deficient. Correlational analyses within the offender group revealed that poor performance on the perceptual shift problem was associated with fewer errors in tasks for working memory and planning.Conclusions. The present results suggest that violent offenders show dual impairments in inhibitory cognitive control. First, they are deficient in shifting attention from one category to another. Secondly, the ability to alter behaviour in response to fluctuations in the emotional significance of stimuli is compromised. These deficits might constitute cognitive reflections of the biological prefrontal alterations observed in this group of people.
The Danish PET/depression project: PET findings in patients with major depression
Authors: VIDEBECH P. , RAVNKILDE B. , PEDERSEN A. R. , EGANDER A. , LANDBO B. , RASMUSSEN N. A. , ANDERSEN F. , STØDKILDE-JØRGENSEN H. , GJEDDE A. , ROSENBERG R. 
Published: July 2002

Background. It is hypothesized from previous positron emission tomography (PET) studies of patients with major depression that dysfunction of regions of the limbic system and the frontal lobes in close connection with the basal ganglia is involved in the pathophysiology of major depression.Methods. By means of PET and 15O labelled radioactive water we determined an index of the neuronal activity by mapping the cerebral blood flow distribution of 42 unselected in-patients suffering from moderate to severe depression and 47 healthy controls controlling for age and gender. The PET maps were co-registered to magnetic resonance images of the anatomy of the brain.Results. The functions-of-interest analysis revealed significant gender differences in cerebral blood flow and changes in the relative distribution of the blood with increasing age. The patients had increased activity of the hippocampus and the cerebellum compared to the healthy controls when corrected for these confounders and the influence of antidepressant medication. Furthermore, data in the Danish Psychiatric Central Register showed that the patients studied were representative of the population of depressed patients admitted to the hospital during the study period.Conclusion. Our main finding is increased blood flow to the hippocampus, even when controlling for a number of confounders. This is in accordance with a rapidly expanding literature suggesting an important role for this structure in major depression.
Differential effects of transdermal nicotine on microstructured
analyses of tics in Tourette's syndrome: an open study
Authors: DURSUN SERDAR M. , REVELEY MICHAEL A. 
Published: July 2002

Background. The treatment of Tourette's syndrome
(TS) is often unsatisfactory. However, there is some evidence that
transdermal nicotine patch (TNP) application may improve tics of
non-smoking TS patients who are refractory to haloperidol
treatment.Methods. In this open study we applied two 10 mg TNP for 2
consecutive days to four TS patients whose symptoms were not
controlled by haloperidol and to a never-medicated TS patient, all of
whom are non-smokers. The Yale Global Tic Severity Scale (YGTSS) and a
quantified video-taped micro-structured analysis of tics (head-shake
tics, eye-blinks, vocal tics, facial grimace and other body tics) were
both carried out to assess the change after the application of TNP.Results. TNP application significantly reduced the YGTSS
by an average of 50%, with no reported side-effects, for up to 4 weeks
but not 16 weeks, as compared with TNP-free period. Consistent with
these results, the total counts of tics also showed a significant
decrease for up to 4 weeks after the TNP application.Conclusion. TNP application differentially affected
individually quantified tics, which may suggest a differential role of
nicotinic receptors in the generation of different tics.
Somatic and psychological models of common

mental disorder in primary care in India
Authors: PATEL V. , PEREIRA J. , MANN A. H. 
Published: July 2002

Background. Primary care attenders with a common mental

disorder (CMD) frequently present

with somatic symptoms. This study aimed to examine somatic and

psychological models of CMD

in primary care attenders in India.Methods. Cross-sectional survey of attenders at two primary

care clinics. Psychiatric caseness was

determined on three criteria: standardized psychiatric interview

(biomedical criterion), patients'

self-assessment of emotional disorder (emic criterion) and health

care provider diagnosis. The

GHQ-12 and the PPQ, which emphasize psychological and somatic

symptoms respectively, were

used as screening instruments.Results. Although somatic symptoms were the presenting

complaints for 97% of subjects, 51% of

subjects with a biomedically defined CMD had a psychological illness

attribution. Patients with

psychological attributions were more likely to be women, to have a

longer duration of illness, to

have higher CISR scores and were more likely to be recognized by

the primary health care (PHC)

physician. The GHQ-12 was superior to the PPQ in identifying cases

of CMD against the

biomedical criterion for both psychologizers and somatizers; both

instruments performed equally

well against the emic and care provider criteria.Conclusions. Psychological models may be acquired by

patients as CMD becomes more chronic or

severe, making them more likely to be detected by PHC physicians.

Psychological symptoms are

superior to somatic symptoms in detecting CMD. Shorter versions of

the GHQ have comparable

discriminating abilities to the 12-item version and offer the

practical advantage of brevity, which may

make them more acceptable to PHC physicians as a clinical screening tool.
The influence of age and sex on the prevalence of

depressive conditions: report from the

National Survey of Psychiatric Morbidity
Authors: BEBBINGTON P. E. , DUNN G. , JENKINS R. , LEWIS G. , BRUGHA T. , FARRELL M. , MELTZER H. 
Published: July 2002

Background. Women are consistently reported to

have a greater prevalence of depressive disorders

than men. The reason for this is unclear, and is as likely to be

social as biological. There is some

evidence that the excess of depression is greater during women's

reproductive lives. Data from the

National Survey of Psychiatric Morbidity were used to test the

hypothesis that the excess

disappeared in the post-menopausal years and that obvious social

explanations for this were inadequate.Method. Subjects (N=9792) from a random sample of

the British population provided data for

the analysis. Psychiatric assessment was carried out by lay

interviewers using the CIS-R. Subjects

with ICD-10 depressive episode or mixed anxiety/depression

were compared with the remainder.

Social variables that were likely to contribute to a post-menopausal

decline in depressive disorders

were controlled in logistic regression analyses.Results. There was a clear reversal of the sex difference

in prevalence of depression in those over age

55. This could not be explained in terms of differential effects of

marital status, child care, or employment status.Conclusions. This large and representative survey adds

considerably to the increasingly held view

that the sex difference in prevalence of depression is less apparent

in later middle age. This may be

linked to the menopause, and our attempts to explain it in terms of

obvious conditions among social

variables were not successful. More specific studies are required to

clarify the finding.
Urbanization and psychosis: a study of 1942–1978
birth cohorts in The Netherlands
Authors: MARCELIS M. , NAVARRO-MATEU F. , MURRAY R. , SELTEN J.-P. , VAN OS J. 
Published: July 2002

Background. Urban birth is associated with later schizophrenia.
This
study examined whether this
finding is diagnosis-specific and which individuals are most at risk.Methods. All live births recorded between 1942 and 1978 in

any of the 646 Dutch municipalities
were followed-up through the National Psychiatric Case Register for
first psychiatric admission for
psychosis between 1970 and 1992 (N=42115).Results. Urban birth was linearly associated with later
schizophrenia (incidence rate ratio linear
trend (IRR), 1·39; 95% confidence interval (95% CI), 1·36–1·42),

affective psychosis (IRR, 1·18;
95% CI, 1·15–1·21) and other psychosis (IRR, 1·27;
95% CI,
1·24–1·30). Individuals born in the
highest category of the three-level urban exposure were around twice as
likely to develop
schizophrenia. Associations were stronger for men and for individuals
with early age of onset. The
effect of urban birth was also stronger in the more recent birth cohorts.Conclusions. There are quantitative differences between
diagnostic categories in the strength of the
association between urban birth and later psychiatric disorder. High
rates of psychosis in urban
areas may be the result of environmental factors associated with urbanization,

the effect of which appears to be increasing over successive generations.
Schizophrenic patients who were never treated – a study in an
Indian urban community
Authors: PADMAVATHI R. , RAJKUMAR S. , SRINIVASAN T. N. 
Published: July 2002

Background. A significant number of patients with
severe psychiatric disorders remain untreated in
the community although health services are available. The factors related

to non-treatment are not well understood.Method. A door-to-door survey was conducted on an Indian urban

population of 100 000 using
standardized screening and clinical instruments as a part of a larger epidemiological
study.
Treatment status was determined from multiple sources of information.Results. Nearly one-third of 261 schizophrenia patients were

found never to have received
treatment. They were older in age and ill for a longer duration than
those who had been treated and
were more symptomatic and severely disabled. They were more often uneducated
and divorced and
lived with larger extended/joint families. This last factor was
considered as being the important
factor in determining whether the patient received treatment.Conclusion. The larger extended/joint family, which
was able to compensate and cope with the
dysfunctional member, seemed to be the crucial factor related to non-treatment

of the schizophrenic patient.
Life events and post-traumatic stress: the
development of a new measure for children and adolescents
Authors: COSTELLO E. J. , ANGOLD A. , MARCH J. , FAIRBANK J. 
Published: July 2002

Background. A new interview measure of life events and
post-traumatic stress disorder (PTSD) has
been developed for children and adolescents aged 9 through 17, for use
in both epidemiological and
clinical studies. It includes ‘high magnitude’ events associated
with PTSD as well as other ‘low
magnitude’ events.Method. The interview is designed as a module of the Child
and Adolescent Psychiatric Assessment,
an interviewer-based interview conducted with parent and child separately
by trained lay
interviewers. The module includes: (1) questions about a wide range of
events; (2) a screen for key
PTSD symptoms (painful recall, avoidance, hypervigilance); and (3) a detailed
interview on all
PTSD symptoms, including onset, duration, severity and co-morbidity. A
test–retest reliability
study was conducted with 58 parents and children, who were interviewed
twice by different
interviewers.Results. Intraclass correlations were 0·72 (child) and
0·83 (parent) for high magnitude events, and
0·62 (child) and 0·58 (parent) for low magnitude events.
Kappa coefficients ranged from high for
violence and sexual abuse to low for child reports of serious accidents
and natural disasters. The
reliability of the PTSD screen symptoms was fair to excellent (κ=0·40–0·79),
and reliability of
PTSD symptoms in those who passed the screen was excellent (ICC=0·94–0·99).
Compared with
a general population sample (N=1015), the clinic-referred subjects
and their parents were twice as
likely to report a traumatic event and, depending on the event, up to 25
times as likely to report
symptoms of PTSD.Conclusions. The results support the reliability and discriminant
validity of the measure.
Mood, neuropsychological function and cognitions in premenstrual
dysphoric disorder
Authors: MAN M. S. , MacMILLAN I. , SCOTT J. , YOUNG A. H. 
Published: July 2002

Background. Neuropsychological function and cognitive correlates of depression have not
previously been examined in a rigorously defined population of patients suffering from premenstrual
dysphoric disorder (PMDD).Method. Mood, neuropsychological function and cognition were measured in 10 PMDD patients
and 10 age-matched controls in both phases of the menstrual cycle in a random order, counter-balanced design.Results. The BDI was significantly elevated in the luteal phase of PMDD patients only while other
cognitive measures showed no significant differences. Working memory was impaired in the luteal
phase of the menstrual cycle with no significant differences between PMDD and control subjects.Conclusion. Despite the small sample size, these results show that the BDI is sensitive to the mood
fluctuations of PMDD patients. An impairment in working memory was also found although this
is a general menstrual cycle effect.