bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stability of viscoelastic shear flows subjected to
steady or oscillatory transverse flow
Authors: RAMANAN V. V. , KUMAR K. A. , GRAHAM M. D. 
Published: July 2002

Experiments and theory show that hydrodynamic instabilities can
arise during flow
of viscoelastic liquids in curved geometries. A recent study has found
that a relatively
weak steady transverse flow can delay the onset of instability in the circular
Couette
geometry until the azimuthal Weissenberg number
Weθ is significantly higher than
without axial flow. In this work we investigate the effect of superposition
of a
time-periodic axial Couette flow on the viscoelastic circular Couette and
Dean flow
instabilities. The analysis, carried out for the upper-convected Maxwell
and Oldroyd-B
fluids, generally shows increased stability compared to when there is no
axial flow.
However, we also find that the system shows instability – synchronous
resonance –
for some values of the axial Weissenberg number,
Wez and forcing frequency ω. In
particular, instability can be induced not only when ω is of the
order of the inverse
relaxation time of the fluid but also when it is much smaller. Scaling
arguments and
numerical results indicate that the high-ω,
low-Wez regime is essentially equivalent to

Wez=0 in the steady case, implying no stabilization.

At high values of ω and Wez,
scaling analysis shows that the flow will always be stable. Numerical results
are in
agreement with these conclusions. Consistent with previous results on parametrically

forced systems, we find that the zero-frequency limit is singular. In this
limit, the
disturbances display quiescent intervals punctuated by periods of large
transient
growth and subsequent decay.This study also presents linear and nonlinear stability results for
the addition of
steady axial Couette and Poiseuille flows to viscoelastic instabilities
in azimuthal Dean
flows. It is shown that, for high Wez,
the qualitative effect of adding a steady axial
flow is similar to that in the circular Couette geometry, with a linear
relationship
between the critical Weθ and Wez.

For low Wez, we find that the flow is stabilized,

unlike in the circular Couette flow where the critical value
of Weθ decreases at low
Wez. Further, weakly nonlinear analysis shows

that the criticality of the bifurcation
depends on the value of Wez
and the solvent viscosity, S. Finally, we also show
the presence of a codimension-2 Takens–Bogdanov bifurcation point
in the linear
stability curve of Dean flow. This point represents a transition from one
mechanism
of instability to another.
Simulation of swept-wing vortices using
nonlinear parabolized stability equations
Authors: HAYNES TIM S. , REED HELEN L. 
Published: July 2002

The nonlinear development of stationary crossflow vortices over a 45° swept NLF(2)-0415 airfoil is studied. Previous investigations indicate that the linear stability theory
(LST) is unable to accurately describe the unstable flow over crossflow-dominated
configurations. In recent years the development of nonlinear parabolized stability
equations (NPSE) has opened new pathways toward understanding unstable
boundary-layer flows. This is because the elegant inclusion of nonlinear and non-parallel effects in the NPSE allows accurate stability analyses to be performed without
the difficulties and overhead associated with direct numerical simulations (DNS).
NPSE results are presented here and compared with experimental results obtained at
the Arizona State University Unsteady Wind Tunnel. The comparison shows that the
saturation of crossflow disturbances is responsible for the discrepancy between LST
and experimental results for cases with strong favourable pressure gradient. However,
for cases with a weak favourable pressure gradient the stationary crossflow disturbances
are damped and nonlinearity is unimportant. The results presented here clearly
show that for the latter case curvature and non-parallel effects are responsible for the
previously observed discrepancies between LST and experiment. The comparison of
NPSE and experimental results shows excellent agreement for both configurations.Through this work, a detailed quantitative comparison and validation of NPSE
with a careful experiment has now been provided for three-dimensional boundary
layers. Moreover, the results validate the experiments of Reibert et al. (1996), and
Radeztsky et al. (1993, 1994) suggesting that their databases can be used by future
researchers to verify theories and numerical schemes. The results show the inadequacy
of linear theories for modelling these flows for significant crossflow amplitude and
demonstrate the effects of weak curvature to be more significant than slight changes
in basic state, especially near neutral-stability locations.
Predictors of mental health service costs for

representative cases of psychosis in south London
Authors: McCRONE P. , THORNICROFT G. , PARKMAN S. , NATHANIEL-JAMES D. , OJURONGBE W. 
Published: July 2002

Background. Increasingly, evaluations of mental health

services include an economic component,

although often only summary statistics such as the mean or median

are reported. Measures of

variation are often limited to the standard error or standard deviation,

though costs are rarely

normally distributed and vary substantially between patients. The

aim of this study is to identify

factors that can explain variations in the cost of mental health

services for epidemiologically representative cases of psychosis.Methods. Cases with ICD-10 diagnoses of functional

psychosis were drawn from a sample that

included all identified cases of psychosis in two geographically

defined sectors in Camberwell, south

London. Mental health service use was measured and costed. A

predictive model was developed

using multiple regression analyses, in which patient characteristics

and previous service use

indicators were used as predictor variables. Services were measured

using the Client Service Receipt Interview.Results. Among the 147 cases included, the amount of cost

variation explained by the model was

31·5%. The most significant predictive factor was social

functioning, which was highly negatively associated with cost.Conclusions. Current mental health service use can be

predicted to a reasonable extent by previous

service use and patient characteristics, especially the degree of

social disability. Identification of such

factors can aid the effective allocation of scarce resources. In

particular, subgroups of patients who

use most resources can be identified and targeted by mental health services.
Lower serum activity of prolyl endopeptidase in
fibromyalgia is related to severity of depressive
symptoms and pressure hyperalgesia
Authors: MAES M. , LIBBRECHT I. , VAN HUNSEL F. , LIN A.-H. , BONACCORSO S. , GOOSSENS F. , De MEESTER I. , De CLERCK L. , BIONDI M. , SCHARPE S. , JANCA A. 
Published: July 2002

Background. The aims of the present study were
to examine serum activities of peptidases, i.e.
prolyl endopeptidase (PEP) and dipeptidyl peptidase IV (DPP IV), in patients
with fibromyalgia
and to examine the effects of subchronic treatment with sertraline on these
variables.Method. Serum PEP and DPP IV activity were measured in 28 normal
volunteers and 21
fibromyalgia patients, classified according to the American College of
Rheumatology criteria.
Tenderness at tender points was evaluated by means of dolorimetry. Fibromyalgia
patients had
repeated measurements of serum PEP and DPP IV both before and after repeated
administration
of sertraline or placebo for 12 weeks.Results. Patients with fibromyalgia had significantly
lower serum PEP activity than normal
volunteers. There were significantly negative correlations
between serum PEP activity and severity
of pressure hyperalgesia and the non-somatic, cognitive symptoms of the
Hamilton Depression
Rating Scale. Fibromyalgia patients with severe pressure
hyperalgesia had significantly lower PEP
activity than normal controls and fibromyalgia patients with
less severe hyperalgesia. Fibromyalgia
patients with severe non-somatic depressive symptoms had significantly
lower serum PEP activity
than normal volunteers. There were no significant changes in serum DPP
IV activity in
fibromyalgia. There were no significant effects of repeated
administration of sertraline on serum
PEP and DPP IV activity in patients with fibromyalgia.Conclusions. The results show that fibromyalgia, and aberrant

pain perception and depressive
symptoms in fibromyalgia are related to lower serum PEP activity. It is
hypothesized that lower
serum PEP activity may play a role in the biophysiology of fibromyalgia
through diminished
inactivation of algesic and depression-related peptides.
Homeless youth in London: I. Childhood
antecedents and psychiatric disorder
Authors: CRAIG T. K. J. , HODSON S. 
Published: July 2002

Background. There has been an increase in the numbers
of homeless young people in Britain. Little
is known of the health and social welfare needs of this population.Method. This case–control study compares a random sample
of homeless people aged under 22
years recruited from consecutive attenders at two of London's largest
facilities for homeless young
people with a contemporaneous sample of domiciled young people recruited
through general
practice registration lists. The homeless and domiciled groups were compared
on measures of
childhood care, education and psychiatric disorder.Results. One hundred and sixty-one homeless people (88% of those
approached) and 107 domiciled
subjects (60% of those approached) were interviewed. Sixty-nine per cent
of homeless and a third
of the domiciled subjects reported a childhood lacking in affection, with
indifferent and often violent
carers. Psychiatric disorder was identified in 62% of homeless respondents
and a quarter of the
domiciled population. A fifth of homeless and 5 domiciled respondents had
attempted suicide in the
previous year. Multivariate analysis suggest that childhood adversity,
low educational attainment
and the prior presence of psychiatric disorder all independently increase
the likelihood of
homelessness in a youthful population.Conclusions. The evidence presented in this paper supports
the hypotheses that characterize the
young homeless population as experiencing higher rates of childhood adversity
and psychiatric
disorder than their domiciled contemporaries. A tentative model is suggested
whereby childhood
experiences, educational attainment and the prior presence of psychiatric
disorder all independently
increase the likelihood of homelessness in a youthful population.
Panic disorder following torture by suffocation is associated with

predominantly respiratory symptoms
Authors: BOUWER COLIN , STEIN DAN 
Published: July 2002

Background. We previously reported that in panic disorder
a history of near-suffocation is
associated with predominantly respiratory panic attacks. It might be hypothesized
that the
near-suffocation experienced in certain kinds of torture is also associated
with the development of
predominantly respiratory panic attacks.Methods. A sample of patients who had experienced torture (N=14)
was drawn from an Anxiety
Disorders Clinic in South Africa. Subjects were questioned about symptoms
of panic disorder, post-traumatic stress disorder and depression.Results. Patients with a history of torture by suffocation
were more likely than other patients to
complain of predominantly respiratory symptoms during panic attacks. These
patients also
demonstrated higher levels of depressive symptoms.Conclusions. While various interpretations of the data can
be made, it is possible that torture by
suffocation is associated with a specific symptomatic profile. Were such
an association to be
replicated, this would perhaps support the suffocation alarm hypothesis
of panic disorder and
provide evidence that specific environmental factors play a role in the
development of this alarm.
The association between the high interpersonal sensitivity type of
personality and a lifetime history of depression in a sample of
employed Japanese adults
Authors: SAKADO K. , SATO T. , UEHARA T. , SAKADO M. , KUWABARA H. , SOMEYA T. 
Published: July 2002

Background. Although the ‘high interpersonal sensitivity’ type of personality has repeatedly been
shown to be related to depression by case–control studies, no studies have confirmed whether this
association also exists in a non-clinical sample.Methods. Scores on the Interpersonal Sensitivity Measure (IPSM) were compared between
employed Japanese adults with and without a lifetime diagnosis of major depressive disorder. The
diagnosis was provided by the Inventory to Diagnose Depression, Lifetime version. A multiple
logistic regression analysis estimated the odds ratios for having a lifetime diagnosis of depression.Results. The scores on the IPSM were higher in the subjects with a lifetime history of depression
than those without a lifetime history of depression. On the five subscales of the IPSM, the subjects
with a lifetime history of depression showed higher scores on ‘interpersonal awareness’, ‘need for
approval’, and ‘separation anxiety’ than those without a lifetime history of depression. The
multiple logistic regression analysis showed that the subjects with the high interpersonal sensitivity
type of personality had an increased risk for experiencing lifetime depression.Conclusions. The results suggest that high interpersonal sensitivity is a risk factor for depression
even in a non-clinical sample from non-Western culture.
The Mental Adjustment to Cancer (MAC) Scale:
replication and refinement in 632 breast cancer
patients
Authors: OSBORNE R. H. , ELSWORTH G. R. , KISSANE D. W. , BURKE S. A. , HOPPER J. L. 
Published: July 2002

Background. Assessment of adjustment of patients in cancer treatment trials is becoming more
common and increasingly regarded as a useful outcome measure. The widely used Mental
Adjustment to Cancer (MAC) Scale was designed to measure Fighting Spirit (FS), Anxious
Preoccupation (AP), Helpless–hopelessness (HH) and Fatalism.Methods. Questionnaire responses from 632 breast cancer patients were randomly divided into two
groups, one for exploratory analyses and possible scale refinement, and the other for validation
purposes.Results. Estimates of reliability (Cronbach's α) were satisfactory for two scales, FS (α = 0·85) and
HH (α = 0·81), but lower for AP (α = 0·65) and Fatalism (α = 0·64). Exploratory factor analysis
suggested that the MAC Scale might be measuring six independent constructs including two related
to Fighting Spirit (Positive Orientation to the Illness, Minimizing the Illness), two related to
Fatalism (Fatalism-revised, Loss of Control), a construct we have named Angst, and an unchanged
HH construct. Scales developed to measure these constructs were satisfactorily replicated in
confirmatory analyses but some reliabilities were lower than desirable. The general structure of the
MAC Scale remained little changed despite the division of two scales and the suggested removal of
six items. The refined scales correlated with the Hospital Anxiety and Depression scale and the
Medical Coping Modes Questionnaire, indicating good concurrent validity.Conclusions. While reasonable reliability of the original scales persists through analyses of the
MAC Scale, the original factor structure could not be reproduced. Six refined constructs with strong
construct validity were identified within the overall domain of mental adjustment to cancer.
Linguistic processing in high-functioning adults with autism or Asperger's syndrome. Is global coherence impaired?
Authors: JOLLIFFE THERESE , BARON-COHEN SIMON 
Published: July 2002

Background. Linguistic processing was explored in normally intelligent adults with either autism or Asperger's syndrome, to test if global coherence was impaired. Global coherence is the ability to establish causal connections and interrelate local chunks into higher-order chunks so that most linguistic elements are linked together thematically. Since individuals with autism are hypothesized to have weak central coherence then one would predict that the clinical groups would have difficulty integrating information globally so as to derive full meaning.Methods. Two experiments were designed to test global coherence. Experiment 1 investigated whether individuals on the autism spectrum condition could arrange sentences coherently. Experiment 2 investigated whether they were less able to use context to make a global inference. Results. The clinical groups were less able to arrange sentences coherently and use context to make a global inference.Conclusions. The results suggest that individuals on the autism spectrum have impaired global coherence. Arranging sentences and making global inferences correlated highly, suggesting that central coherence may be a unitary force in these different tasks. Of the two clinical groups, the autism group had the greater deficit. The effect that such a deficit would have on one's daily life is discussed, along with possible explanations for the clinical groups' greater difficulty, and suggestions for future research.
The relationship of childhood sexual abuse and depression with somatic symptoms and medical utilization
Authors: NEWMAN M. G. , CLAYTON L. , ZUELLIG A. , CASHMAN L. , ARNOW B. , DEA R. , TAYLOR C. B. 
Published: July 2002

Background. Previous research suggests that childhood sexual abuse is associated with high rates of retrospectively reported medical utilization and medical problems as an adult. The goal of this study was to determine if abused females have higher rates of medical utilization using self-report and objective measures, compared with non-abused females. A further goal was to determine whether findings of prior research would be replicated when childhood physical abuse level was controlled. This study also examined the moderating impact of depressed mood on current health measures in this population.Methods. Six hundred and eight women recruited from a health maintenance organization completed self-report measures of health symptoms for the previous month and doctor visits for the previous year. Objective doctor records over a 2 year period were examined for a subset of 136 of these women.Results. Results showed significantly more self-reported health symptoms and more self-reported doctor visits in abused participants compared with those who reported no childhood history of sexual abuse. Objective doctor visits demonstrated the same pattern with abused participants exhibiting more visits related to out-patient surgery and out-patient internal medicine. In addition, persons who were both sexually abused and depressed tended to visit the emergency room more frequently and to have more in-patient internal medicine and ophthalmology visits than sexually abused participants who reported low depressed mood and non-abused controls.Conclusions. These results replicate prior studies and suggest that current depression may moderate the relationship between sexual abuse and medical problems in adulthood.
KWAME NKRUMAH AND THE CHIEFS: THE FATE OF ‘NATURAL RULERS’ UNDER NATIONALIST GOVERNMENTS
Authors: Rathbone Richard 
Published: July 2002

AbstractTHERE is a popular and reasonably accurate view of pre-colonial government in Africa which believes that Africans were governed by rulers who are usually referred to as chiefs. While there were some societies in Africa where authority was exercised in a less obviously hierarchical fashion, most African polities were dominated by individual rulers whose legitimacy depended, as in so many other parts of the world, upon descent and by their near monopoly of material or spiritual means of coercion. Historians of Africa have obviously been interested in the fate of these institutions over time and have broadly concluded that by the twentieth century these monarchies were dying institutions. There are several studies of very varied cases which range from the virtual extinction of chieftaincy at the hands of colonial powers to others in which colonialism deprived traditional rulers of absolute sovereignty and did so by shielding them from the simultaneous corrosion and vitalisation of modernisation. Like most generalisations, this is caricature. But it is fair to say that modern historiography has regarded chiefs and chieftaincy as the peripheral tags of a pre-modern order; where chieftaincy survived into the second half of the twentieth century, it was because of the un-natural, instrumental preservation of these archaic forms of government and value allocation, by colonialism.
The interpretation of physiology
Authors: Jones Barbara E. 
Published: July 2002

Not at all self-evident, the so-called isomorphisms between the phenomenology and physiology of dreams have been interpreted by Hobson et al. in an arbitrary manner to state that dreams are stimulated by chaotic brainstem stimulation (an assumption also adopted by Vertes & Eastman). I argue that this stimulation is not chaotic at all; nor does it occur in the absence of control from the cerebral cortex, which contributes complexity to brainstem activity as well as meaningful information worth consolidating in the brain during sleep.[Hobson et al.; Vertes & Eastman]
Lucid dreaming: Evidence and methodology
Authors: LaBerge Stephen 
Published: July 2002

Lucid dreaming provides a test case for theories of dreaming. For example, whether or not “loss of self-reflective awareness” is characteristic of dreaming, it is not necessary to dreaming. The fact that lucid dreamers can remember to perform predetermined actions and signal to the laboratory allows them to mark the exact time of particular dream events, allowing experiments to establish precise correlations between physiology and subjective reports, and enabling the methodical testing of hypotheses.[Hobson et al.; Solms]
Velocity, acceleration and deceleration bounds for a time-optimal planner of
a wheeled mobile robot
Authors: Prado Maria , Simón Antonio , Ezquerro Francisco 
Published: July 2002

Three single-valued upper boundary functions for velocity, acceleration and deceleration of a wheeled mobile robot (WMR) are defined as closed mathematical forms over its entire spatial path. The limits deal with mechanical, kinematic and dynamic characteristics of the robot and with task and operating matters. These boundary functions can be computed making use of any robot model, as complex as is needed, since it works offline.All studies are particularised for the robot RAM. A kinematic and a complete dynamic model of this WMR is built, with special attention on the study of wheel-ground contact
efforts. For this purpose an empirical-analytical model of rubber wheel rolling is developed.