bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nonlinear evolution and secondary instabilities
of Marangoni convection in a liquid–gas system
with deformable interface
Authors: GOLOVIN A. A. , NEPOMNYASHCHY A. A. , PISMEN L. M. 
Published: July 2002

The paper presents a theory of nonlinear evolution and
secondary instabilities in
Marangoni (surface-tension-driven) convection in a two-layer
liquid–gas system with
a deformable interface, heated from below. The theory takes into account the motion
and convective heat transfer both in the liquid and in the gas layers. A system of
nonlinear evolution equations is derived that describes a general case of slow
long-scale evolution of a short-scale hexagonal Marangoni convection pattern near the
onset of convection, coupled with a long-scale deformational Marangoni instability.
Two cases are considered: (i) when interfacial deformations are negligible; and (ii)
when they lead to a specific secondary instability of the hexagonal convection.In case (i), the extent of the subcritical region of the hexagonal Marangoni
convection, the type of the hexagonal convection cells, selection of
convection patterns – hexagons, rolls and squares – and
transitions between them are studied, and the
effect of convection in the gas phase is also investigated.
Theoretical predictions are compared with experimental observations.In case (ii), the interaction between the short-scale hexagonal
convection and the
long-scale deformational instability, when both modes of Marangoni convection are
excited, is studied. It is shown that the short-scale convection
suppresses the deformational instability. The latter can appear as a
secondary long-scale instability of
the short-scale hexagonal convection pattern. This secondary instability is shown to
be either monotonic or oscillatory, the latter leading to the excitation of
deformational waves, propagating along the short-scale hexagonal
convection pattern and modulating its amplitude.
Axisymmetric motion of capsules through
cylindrical channels
Authors: QUÉGUINER CHRISTOPHE , BARTHÈS-BIESEL DOMINIQUE 
Published: July 2002

A boundary integral method is used to model the flow of capsules
into pores. An
axisymmetric configuration is considered where the capsule and
the pore axis coincide.
The channel is a cylinder with hyperbolic entrance and exit regions.
The capsule has a
discoidal unstressed shape, is filled with a Newtonian liquid
and is enclosed by a very
thin membrane with various elastic properties (neo-Hookean or area-incompressible).
The motion of the internal capsule liquid and of the suspending fluid is
governed by
the Stokes equations whose solution is expressed as boundary integrals.
Those are
computed by a collocation technique, where points are distributed on the
capsule
interface, on the channel walls and on the entrance and exit sections of
the flow
domain. The capsule interface mechanics follow the theory of large deformations
of
elastic membranes. The numerical model uses a forward time-stepping method,
where
the position and the deformation of the capsule are computed at each time
step.The model allows the study of the effect of a number of parameters (capsule
size
and geometry, membrane elastic properties) on the flow. The entrance length
in the
pore, the steady additional pressure drop at equilibrium and the capsule
deformed
profiles are determined. It is found that the entrance of a capsule
into a pore is not
sensitive to downstream conditions; but the length of tube necessary to
reach steady
conditions depends strongly on capsule size and membrane behaviour. Bursting
of
capsules with a neo-Hookean membrane is predicted to occur through a phenomenon
of continuous elongation. The flow of a capsule with a membrane that resists
area
dilatation depends strongly on particle size and shape.
Stokes flow in collapsible tubes: computation and experiment
Authors: HEIL MATTHIAS 
Published: July 2002

This paper is concerned with the problem of viscous flow in

an elastic tube. Elastic

tubes collapse (buckle non-axisymmetrically) when the transmural pressure
(internal

minus external pressure) falls below a critical value. The tube's

large deformation during the buckling leads to a strong interaction between

the fluid and solid mechanics.In this study, the steady three-dimensional Stokes equations are used
to analyse

the slow viscous flow in such a tube whose deformation is described by
geometrically

nonlinear shell theory. Finite element methods are used to solve

the large-displacement

fluid–structure interaction problem. Typical wall deformations and

flow fields in the

strongly collapsed tube are shown. Extensive parameter studies illustrate

the tube's flow characteristics (e.g. volume flux as a function of
the applied

pressure drop through

the tube) for boundary conditions corresponding to the four fundamental
experimental

setups. It is shown that lubrication theory provides an excellent approximation
of

the fluid traction while being computationally much less expensive than
the solution

of the full Stokes equations. Finally, the computational predictions for
the flow

characteristics and the wall deformation are compared to the results obtained
from

an experiment.
Helical vortices in swirl flow
Authors: ALEKSEENKO S. V. , KUIBIN P. A. , OKULOV V. L. , SHTORK S. I. 
Published: July 2002

Helical vortices in swirl flow are studied theoretically and experimentally.A theory of helical vortices has been developed. It includes the following
results:
an analytical solution describing an elementary helical vortex structure
– an infinitely
thin filament; a solution for axisymmetrical vortices accounting for the
helical shape
of vortex lines and different laws of vorticity distribution; a formula
for calculation
of the self-induced velocity of helical vortex rotation (precession) in
a cylindrical
tube; an explanation of the zone with reverse flow (recirculation zone)
arising in swirl
flows; and the classification of vortex structures.The experimental study of helical vortices was carried out in a vertical
hydrodynamical
vortex chamber with a tangential supply of liquid through turning nozzles.

Various vortex structures were formed owing to changing boundary conditions
on the
bottom and at the exit section of the chamber. The hypothesis of helical
symmetry
is confirmed for various types of swirl flow. The stationary helical vortex
structures
are described (most of them for the first time) the features of which agree
with the
results and predictions of the theoretical model developed. They are the
following:
a rectilinear vortex; a composite columnar vortex; helical vortices screwed
on the
right or on the left; a vortex with changing helical symmetry; a double
helix – two
entangled vortex filaments of the same sign.
Natural convection flow far from a horizontal plate
Authors: NOSHADI VALOD , SCHNEIDER WILHELM 
Published: July 2002

Plane and axisymmetric (radial), horizontal laminar jet flows, produced by natural
convection on a horizontal finite plate acting as a heat dipole, are considered at
large distances from the plate. It is shown that physically acceptable self-similar
solutions of the boundary-layer equations, which include buoyancy effects, exist in
certain Prandtl-number regimes, i.e. 0.5<Pr[les ]1.470588 for
plane, and Pr>1 for
axisymmetric flow. In the plane flow case, the eigenvalues of the self-similar solutions
are independent of the Prandtl number and can be determined from a momentum
balance, whereas in the axisymmetric case the eigenvalues depend on the Prandtl
number and are to be determined as part of the solution of the eigenvalue problem.
For Prandtl numbers equal to, or smaller than, the lower limiting values of 0.5 and
1 for plane and axisymmetric flow, respectively, the far flow field is a non-buoyant
jet, for which self-similar solutions of the boundary-layer equations are also provided.
Furthermore it is shown that self-similar solutions of the full Navier–Stokes equations
for axisymmetric flow, with the velocity varying as 1/r, exist for arbitrary values of
the Prandtl number.Comparisons with finite-element solutions of the full Navier–Stokes equations show
that the self-similar boundary-layer solutions are asymptotically approached as the
plate Grashof number tends to infinity, whereas the self-similar solution to the full
Navier–Stokes equations is applicable, for a given value of the Prandtl number, only
to one particular, finite value of the Grashof number.In the Appendices second-order boundary-layer solutions are given, and uniformly
valid composite expansions are constructed; asymptotic expansions for large values of
the lateral coordinate are performed to study the decay of the self-similar boundary-layer flows; and the stability of the jets is investigated using transient numerical
solutions of the Navier–Stokes equations.
Depression and social stress in Pakistan
Authors: HUSAIN N. , CREED F. , TOMENSON B. 
Published: July 2002

Background. The high prevalence of depression in developing countries is not well understood. This
study aimed to replicate the previous finding of a high prevalence of depression in Pakistan and
assess in detail the associated social difficulties.Method. A two-phase survey of a general population sample in a Pakistani village was performed.
The first-phase screen used the Personal Health Questionnaire (PHQ) and the self-rating
questionnaire (SRQ). A one in two sample of high scorers and a one in three sample of the low
scorers were interviewed using the Psychiatric Assessment Schedule (PAS) and Life Events and
Difficulties Schedule (LEDS).Results. A total of 259 people were screened (96% response rate). The second stage yielded 55 cases,
of whom 54 had depressive disorder, and 48 non-cases. The adjusted prevalence of depressive
disorders was 44·4% (95% CI 35·3 to 53·6): 25·5% in males and 57·5% in females. Nearly all cases
had lasted longer than 1 year. Comparison of the cases and non-cases indicated that cases were less
well educated, had more children and experienced more marked, independent chronic difficulties.
Multivariate analysis indicated that severe financial and housing difficulties, large number of
children and low educational level were particularly closely associated with depression.Conclusion. This study confirms the high prevalence of depressive disorders in Pakistan and
suggests that this may be higher than other developing countries because of the high proportion of
the population who experience social adversity.
The association between obstetric complications and childhood-onset schizophrenia: a replication study
Authors: MATSUMOTO H. , TAKEI N. , SAITO F. , KACHI K. , MORI N. 
Published: July 2002

Background. Many previous studies have shown that individuals who develop schizophrenia in adult life are more likely than normal controls to have a history of obstetric complications (OCs) at birth. However, little attention has been paid to the involvement of OCs in the risk of developing childhood-onset schizophrenia (COS). In our earlier report, we found an association between OCs and the development of COS. In this study, we determined whether the association could be replicated in another, independent set of patients with COS.Methods. OCs, birth weight and gestational age were retrospectively assessed in 35 children, aged between 14 and 15 years old (average 15·4 years), who met the DSM-III-R criteria for schizophrenia, and in age- and gender-matched controls (children with anxiety disorders).Results. The COS patients showed significantly greater scores in all of the three measures of OCs according to the Parnas et al. scale compared to controls. Moreover, individuals exposed to OCs were about 3·2 times (odds ratio = 3·22; 95% confidence interval, 1·1–9·8) more likely to develop schizophrenia than those without a history of OCs. The mean birth weight was significantly lower in schizophrenics than in controls (P < 0·05). The frequency of prematurity signs with weight < 2500 g was significantly higher in schizophrenics than in controls (P < 0·05).Conclusion. Repeatedly reported association between OCs and adult-onset schizophrenia have also been demonstrated in patients with COS. This suggests that there may be a continuity between childhood- and adult-onset schizophrenia.
Aberrant brain activation following motor skill learning in schizophrenic patients as shown by functional magnetic resonance imaging
Authors: KODAMA S. , FUKUZAKO H. , FUKUZAKO T. , KIURA T. , NOZOE S. , HASHIGUCHI T. , YAMADA K. , TAKENOUCHI K. , TAKIGAWA M. , NAKABEPPU Y. , NAKAJO M. 
Published: July 2002

Background. Motor skill learning may be impaired in schizophrenia. While functional brain imaging studies have shown reduced activation during motor task performance in schizophrenic patients, brain activity changes with motor skill learning in these patients have not been studied by functional imaging.Methods. A sequential complex motor task involving the right hand was performed by nine medicated schizophrenic patients and 10 age-matched healthy controls. Functional magnetic resonance images were obtained using a gradient echo, echoplanar imaging (EPI) pulse sequence before and after 1 week of training in performing the task.Results. Bilaterally, patients showed significantly less blood oxygenation level-dependent (BOLD) signal response in the premotor area (PMA) before beginning motor training than controls. BOLD signal response increased in the left PMA of schizophrenic patients after 1 week of motor training; in contrast, the signal decreased in the left PMA of control subjects. Training effects concerning the number of finger movement sequences achieved did not differ between groups. Daily neuroleptic dose did not significantly affect changes with training in BOLD signal response in the PMA.Conclusions. These preliminary results suggest that schizophrenic patients have dysfunction of neural networks in areas including the PMA that are involved in executing a complex motor task. In terms of brain activity, motor learning may be less efficient or slower in the patients than in healthy subjects.
Psychosocial sequelae of the 1989 Newcastle
earthquake: II. Exposure and morbidity profiles
during the first 2 years post-disaster
Authors: CARR V. J. , LEWIN T. J. , WEBSTER R. A. , KENARDY J. A. , HAZELL P. L. , CARTER G. L. 
Published: July 2002

Background. A sample of 1089 Australian adults was selected for the longitudinal component of
the Quake Impact Study, a 2-year, four-phase investigation of the psychosocial effects of the
1989 Newcastle earthquake. Of these, 845 (78%) completed a survey 6 months post-disaster as
well as one or more of the three follow-up surveys.Methods. The phase 1 survey was used to construct dimensional indices of self-reported
exposure to threat the disruption and also to classify subjects by their membership of five ‘at
risk’ groups (the injured; the displaced; owners of damaged small businesses; helpers in threat
and non-threat situations). Psychological morbidity was assessed at each phase using the 12-item
General Health Questionnaire (GHQ-12) and the Impact of Event Scale (IES).Results. Psychological morbidity declined over time but tended to stabilize at about 12 months
post-disaster for general morbidity (GHQ-12) and at about 18 months for trauma-related (IES)
morbidity. Initial exposure to threat and/or disruption were significant predictors of psychological
morbidity throughout the study and had superior predictive power to membership of the
targeted ‘at risk’ groups. The degree of ongoing disruption and other life events since the earthquake
were also significant predictors of morbidity. The injured reported the highest levels of
distress, but there was a relative absence of morbidity among the helpers.Conclusions. Future disaster research should carefully assess the threat and disruption experiences
of the survivors at the time of the event and monitor ongoing disruptions in the aftermath in
order to target interventions more effectively.
Qualitative magnetic resonance imaging findings in geriatric
depression. Possible link between later-onset depression and
Alzheimer's disease?
Authors: GREENWALD B. S. , KRAMER-GINSBERG E. , BOGERTS B. , ASHTARI M. , AUPPERLE P. , WU H. , ALLEN L. , ZEMAN D. , PATEL M. 
Published: July 2002

Background. Several clinical and neuroimaging
investigations support the notion that underlying brain changes may
relate to depression in older patients, especially those with a
later-age initial episode. However uncertainty still exists about
diagnostic and pathogenic significance of structural brain
abnormalities in aged depressives, in part because many studies lack
all-elderly and age-similar normal comparison populations.Methods. Brain morphology of elderly depressives
(N = 30) and normal controls (N = 36) was compared
by assessing magnetic resonance imaging (MRI) brain scans with
qualitative criteria-based scales. Ratings included lateral and third
ventricle enlargement, and cortical, medial temporal, and caudate
atrophy.Results. Significant differences between depressed and
control groups were not demonstrated. Later-onset depressives had
significantly more left medial temporal and left caudate atrophy than
early-onset counterparts of similar age. Medial temporal atrophy
significantly correlated with cognitive impairment and was not related
to physical illness. Depressives with medial temporal atrophy
(N = 7) were older and had later age at onset of depression
than those without such changes. Cerebrovascular disease risk factors
did not predict MRI abnormalities.Conclusions. Results indicate non-specificity and lack of
homogeneity of qualitatively measured structural brain changes in
geriatric depression, but suggest that pathology of specific,
lateralized brain regions may be implicated in some later-onset
patients. The relationship between medial temporal atrophy and
late-onset depression raises the possibility that such patients may
suffer from as-yet undeclared Alzheimer's disease. Lack of
association between cerebrovascular disease risk factors and brain
changes suggests other pathophysiological contributions.
Late-onset depressive disorders: a preventable variant of cerebrovascular
disease?
Authors: HICKIE IAN , SCOTT ELIZABETH 
Published: July 2002

The severe depressive disorders of late life are associated with

high rates of medical morbidity and
mortality, cognitive impairment, suicide, disability, complex treatment
regimens,
institutionalization and high costs to the community (Murphy, 1983;
Murphy et al. 1988; Bruce & Leaf,
1989; NIH Consensus Development Panel, 1992; Alexopoulos
et al. 1993a, b; Brodaty et al. 1993;

Bruce et al. 1994; Forsell et al. 1994; Hickie et
al. 1995;
Blazer, 1996). Those disorders that are
accompanied by cognitive impairment and/or concurrent medical morbidity
have a particularly
poor outcome (Bruce & Leaf, 1989; Alexopoulos et al.
1993b; Hickie et al. 1995, 1997a). Although

psychosocial models of late-life depression place considerable importance
on age-related
psychological and social risk factors, those who survive into
later life may actually be characterized
by psychological resilience (Henderson, 1994; Blazer, 1997).Current aetiological research in late-life depression, therefore,
places particular emphasis on the
potential role of biological risk factors. The potential importance
of vascular risk factors is receiving
renewed attention and may provide opportunities for specific prevention

and intervention strategies
in high-risk populations. This emphasis on possible vascular
risk factors, and the wider importance
of vascular pathologies in late-life neuropsychiatric disorders,
mirrors the emphasis of much earlier
clinico-pathological studies (Binswanger, 1894; Alzheimer, 1895). The specific
focus on the
importance of small progressive changes within the subcortical
white matter, as distinct from more
discrete cortical infarcts (Olszewski, 1962), is now supported by the emerging
neuroimaging
literature and theoretical constructs in late-life depression
(Krishnan, 1991, 1993; Hickie et al. 1996, 1997b;
Krishnan et al. 1997).
Long-term outcome of severe puerperal psychiatric illness: a 23 year follow-up study
Authors: ROBLING S. A. , PAYKEL E. S. , DUNN V. J. , ABBOTT R. , KATONA C. 
Published: July 2002

Background. Although there have been many follow-up studies of severe puerperal psychiatric
illness, few have been very long-term.Methods. Sixty-four subjects from 85 (75·3%) in an unselected sample of women admitted to a
psychiatric hospital within 6 months of childbirth were successfully followed up a mean of 23 years
(range 17–28) later. Most subjects were interviewed in detail, with further information obtained
from general practice and hospital records. Data included subsequent illnesses and diagnoses,
subsequent childbirth, longitudinal social function, current symptoms and social function.Results. Seventy-five per cent of subjects had further psychiatric illnesses, most of them unrelated
to childbirth, and 37% had at least three subsequent episodes. The risk of puerperal psychiatric
illness was 29% in subsequent pregnancies. At outcome interview the majority of subjects were well,
with satisfactory social adjustment. Diagnoses in subsequent psychiatric illnesses showed
considerable consistency with index diagnoses, with some shift to bipolar disorder. Further illnesses
were less likely to occur where the index illness occurred with first child, onset was within 1 month
of delivery, and where the index diagnosis was unipolar depression.Conclusions. There is a high risk of subsequent non-puerperal recurrences following severe
puerperal psychotic illness, showing considerable diagnostic consistency with the index episode, but
with good functional outcome. Puerperal illnesses showed strong continuities with non-puerperal
illnesses in these women.
History of childhood sexual or physical abuse in
Japanese patients with eating disorders: relationship
with dissociation and impulsive behaviours
Authors: NAGATA T. , KIRIIKE N. , IKETANI T. , KAWARADA Y. , TANAKA H. 
Published: July 2002

Background. Empirical data regarding prevalence of sexual and physical abuse histories in Japanese
patients with eating disorders is lacking, in contrast to Western countries. This study investigated
the prevalence of traumatic events in Japanese patients with eating disorders, and examined the
relationship between such traumatic events and clinical features.Methods. Subjects consisted of 33 patients with anorexia nervosa restricting type (RAN), 40
patients with anorexia nervosa binge eating/purging type (AN–BP), 63 patients with bulimia
nervosa purging type (BN) and 99 healthy controls. All were female and diagnoses were based on
DSM-IV. The Physical and Sexual Abuse Questionnaire (PSA), Eating Disorder Inventory (EDI)
and Dissociation Experience Scale (DES) were administered to all of the subjects.Results. Paradoxically, victims of minor sexual abuse committed by Chikan (a Japanese word
indicating a person who commits minor sexual crimes) were more prevalent among controls than
among patients with RAN, AN–BP or BN. However, physical punishment histories tended to be
more prevalent among patients with AN–BP or BN than among RAN or controls. Only AN–BP
and BN patients with physical punishment histories had twofold higher scores for DES and
significantly more frequent histories of self-mutilation (67% v. 33%) compared with patients
without such histories.Conclusion. An abuse history is not essential or a prerequisite to developing an eating disorder in
Japan.