bluuebunny/crossref_metadata_2025_split huggingface dataset:
On constructing realizable, conservative mixed scalar equations using the eddy-damped quasi-normal Markovian theory
Authors: ULITSKY MARK , COLLINS LANCE R. 
Published: July 2002

The eddy-damped quasi-normal Markovian (EDQNM) turbulence theory has been
applied to the covariance spectrum of two passive isotropic scalars with different
diffusivities in stationary isotropic turbulence. A rigorous application of EDQNM,
which introduces no new modelling assumptions or constants, is shown to yield a
covariance spectrum that violates the Cauchy–Schwartz inequality over some of the
wavenumbers. One approach to this problem is to derive a model based on a stochastic
differential equation, as its presence guarantees realizability. For an isotropic scalar,
it is possible to construct a Langevin equation for the Fourier transform of the scalar
concentrations that is consistent with each EDQNM scalar autocorrelation spectrum.
The Langevin equations can then be used to construct a model for the covariance
spectrum that is realizable. However, the resulting covariance transfer term does not
properly conserve the scalar covariance, and so the model is still not satisfactory. The
problem can be traced to the Markovianization step, which leads to the presence of
the scalar diffusivities in the transfer functions in an unphysical fashion. A simple fix
is described which reconciles the two approaches and gives conservative, realizable
results for all time.Next, we apply the EDQNM theory to a more general system involving the mixing
of anisotropic scalars. Anisotropy in this case results from a uniform mean gradient
of the two scalar concentrations in one direction. As with the isotropic scalars, direct
application of the EDQNM closure results in a covariance spectrum that violates the
Cauchy–Schwartz inequality; however, in this case it is not as simple to construct a
Langevin model that reproduces all of the spectral interactions that result from the
EDQNM procedure. Nevertheless, we show that the same modification of the inverse
time scale as is done for the isotropic scalar results in an anisotropic scalar covariance
spectrum that is realizable for all times.
On linear and nonlinear instability of
the incompressible swept attachment-line boundary layer
Authors: THEOFILIS VASSILIOS 
Published: July 2002

The stability of an incompressible swept attachment-line
boundary layer flow is studied
numerically, within the Görtler–Hämmerlin
framework, in both the linear and nonlinear two-dimensional
regimes in a self-consistent manner. The initial-boundary-value
problem resulting from substitution of small-amplitude excitation
into the incompressible Navier–Stokes equations
and linearization about the generalized Hiemenz
profile is solved. A comprehensive comparison of all linear
approaches utilized to
date is presented and it is demonstrated that the linear
initial-boundary-value problem
formulation delivers results in excellent agreement with
those obtained by solution of
either the temporal or the spatial linear stability theory
eigenvalue problem for both
zero suction and a layer in which blowing is applied. In
the latter boundary layer
recent experiments have documented the growth of instability
waves with frequencies
in a range encompassed by that of the unstable
Görtler–Hämmerlin linear modes
found in our simulations. In order to enable further
comparisons with experiment
and, thus, assess the validity of the
Görtler–Hämmerlin theoretical model, we make
available the spatial structure of the eigenfunctions at
maximum growth conditions.The condition on smallness of the imposed excitation is
subsequently relaxed and
the resulting nonlinear initial-boundary-value problem is
solved. Extensive numerical
experimentation has been performed which has verified
theoretical predictions on
the way in which the solution is expected to bifurcate from
the linear neutral loop.
However, it is demonstrated that the two-dimensional
model equations considered do
not deliver subcritical instability of this flow; this
strengthens the conjecture that three-dimensionality is,
at least partly, responsible for the observed discrepancy
between the linear theory critical Reynolds number and the
subcritical turbulence observed either
experimentally or in three-dimensional numerical simulations.
Further, the present
nonlinear computations demonstrate that the unstable
flow has its line of maximum
amplification in the neighbourhood of the experimentally
observed instability waves,
in a manner analogous to the Blasius boundary layer. In
line with previous eigenvalue
problem and direct simulation work, suction is observed to
be a powerful stabilization
mechanism for naturally occurring instabilities of small amplitude.
Initial formation of channels and shoals in a
short tidal embayment
Authors: SCHUTTELAARS H. M. , DE SWART H. E. 
Published: July 2002

It is demonstrated, by using a simple model, that bedforms in a short tidal embayment
can develop due to a positive feedback between tidal currents, sediment transport
and bedforms. The water motion is modelled by the depth integrated shallow water
equations. The system is forced by a prescribed free-surface elevation at the entrance
of the embayment. For the sediment dynamics a diffusively dominated suspended
load transport model is considered. Tidal averaging is used to obtain the bottom
profiles at the long morphological time scale.The stability of a constantly sloping equilibrium bottom profile is studied for
various combinations of the model parameters. It turns out that without a mechanism
that generates vorticity this equilibrium profile is stable. In that case small-scale
perturbations can at most become marginally stable if no bedload term in the bottom
evolution equation is incorporated. If vorticity is generated, in our model by bottom
friction torques, the basic state is unstable. The spatial patterns of the unstable modes
and their growth rates depend, among other things, on the strength of the bottom
friction, the width of the embayment and the grain size: if the sediment under consideration
consists of large particles, the equilibrium will be more stable than when
smaller particles are considered. Without a diffusive term in the bed evolution equation,
small-scale perturbations become unstable. To avoid this physically unrealistic
behaviour bedload terms are included in the sediment transport. Furthermore, it is
shown that using an asymptotic expansion for the concentration as given in earlier
literature is only valid for small or moderate mode numbers and the technique is
extended to large mode numbers. A physical interpretation of the results is also given.
Towards an understanding of modern political ideology in
Africa: the case of the Ovimbundu of Angola
Authors: Heywood Linda M. 
Published: July 2002

In 1992, several national newspapers in America and Europe ran

headline stories which accused Jonas Savimbi, the leader of UNITA,
the nationalist movement which had been locked in a vicious civil war
with the MPLA–PT government of Angola, of conducting witchcraft
trials and burnings of witches at his liberation base at Jamba. The
revelations, provided by two high-ranking defectors from UNITA,
caused an outcry among both critics and supporters, with all predicting

Savimbi's ignominious defeat. Savimbi's longtime critics expected
the
latest scandal to deprive him of his remaining credibility, and predicted

that the support he had gathered as a fighter for Angolan nationalism
and a supporter of democracy would evaporate.On the contrary, the incident had little impact on Savimbi's stature

among his Ovimbundu supporters. Later that year he went on to win
the majority of the Ovimbundu votes in the United Nations sponsored
elections, and gained a chance to be in a run-off election against José

Eduardo dos Santos for the presidency of Angola. Details about these
and similar incidents which have taken place in Africa from the time
of conquest reflect a political legacy that has deep roots in Africa's
pre-colonial past. They also illustrate some of the fundamental differences

that exist between African and Western conceptions of political
behaviour and ideology that need to be addressed.
Sanskrit for the Nation
Authors: Ramaswamy Sumathi 
Published: July 2002

. . . the people of India love and venerate Sanskrit with a feeling which is next only to that of patriotism towards Mother India.Report of the Sanskrit Commission, 1956–57This essay raises the language question in its relationship to the wider problematic of the nationalization of pasts by focusing on the curious and puzzling status accorded to Sanskrit in the nationalization of the Indian past in this century. I use the words ‘curious’ and ‘puzzling’ deliberately, for the Sanskrit issue unsettles many well-entrenched assumptions about language and nationalism that circulate in scholarly circles and popular imagination. Just as crucially, Sanskrit's (mis)adventures in the past century or so, draw our attention to the troubling linguistic turns taken by the nationalization process in India with its disquieting complicity with colonial categories and certitudes. The concerns of this paper have thus been shaped by three related issues pertaining to language, nationalism, and modernity.
A population-based incidence study of chronic fatigue
Authors: LAWRIE S. M. , MANDERS D. N. , GEDDES J. R. , PELOSI A. J. 
Published: July 2002

Background. Most research on syndromes of chronic
fatigue has been conducted in clinical settings and is therefore
subject to selection biases. We report a population-based incidence
study of chronic fatigue (CF) and chronic fatigue syndrome (CFS).Methods. Questionnaires assessing fatigue and emotional
morbidity were sent to 695 adult men and women who had replied to a
postal questionnaire survey 1 year earlier. Possible CFS cases,
subjects with probable psychiatric disorder and normal controls were
interviewed.Results. Baseline fatigue score, the level of emotional
morbidity and a physical attribution for fatigue were risk factors for
developing CF. However, after adjusting for confounding, pre-morbid
fatigue score was the only significant predictor. A minority of CF
subjects, all female, had consulted their general practitioner; higher
levels of both fatigue and emotional morbidity were associated with
consultation. Possible CFS cases reported similar rates of current and
past psychiatric disorder to psychiatric controls, but after
controlling for fatigue or a diagnosis of neurasthenia the current
rates were more similar to those of normal controls. Two new cases of
CFS were confirmed.Conclusions. Both fatigue and emotional morbidity are
integral components of chronic fatigue syndromes. The demographic and
psychiatric associations of CFS in clinical studies are at least
partly determined by selection biases. Given that triggering and
perpetuating factors may differ in CFS, studies that examine the
similarities and differences between chronic fatigue syndromes and
psychiatric disorder should consider both the stage of the illness and
the research setting.
Frontal dysfunction in neurologically normal chronic alcoholic subjects:

metabolic and neuropsychological findings
Authors: DAO-CASTELLANA M. H. , SAMSON Y. , LEGAULT F. , MARTINOT J. L. , AUBIN H. J. , CROUZEL C. , FELDMAN L. , BARRUCAND D. , RANCUREL G. , FÉLINE A. , SYROTA A. 
Published: July 2002

Background. Neuropsychological and imaging studies suggest
that
frontal dysfunction may occur in apparently normal chronic alcoholic subjects.Methods. To investigate this issue further, we performed neuropsychological

and fluorodeoxy-glucose-PET studies in 17 chronic alcoholics without
patent neurological and psychiatric complications.Results. Metabolic abnormalities were found in the mediofrontal

and in the left dorsolateral
prefrontal cortex, but not in the orbitofrontal cortex. Neuropsychological
testing revealed
significantly reduced verbal fluency and impaired performance on the Stroop
test. The mediofrontal
hypometabolism correlated with the reduction in verbal fluency and the
time necessary to perform
the interference condition of the Stroop test. The left dorsolateral prefrontal
hypometabolism
correlated with the number of errors on the Stroop test.Conclusion. These data indicate that circumscribed frontal

dysfunctions may occur in chronic
alcoholic subjects before clinically obvious neurological complications,

and may account for some
of the alcohol-related neuropsychological and behavioural impairments.
Early and chronic stress and their relation to breast cancer
Authors: JACOBS JOHN R. , BOVASSO GREGORY B. 
Published: July 2002

Background. The study examined the role of parental death and chronic depression with severe
episodes in affecting risk of breast cancer. This avenue of research is in accord with oncology
findings, which suggests that causative factors of breast cancer occur and develop over a period of
20 years or longer.Methods. Participants consisted of 1213 women in the Baltimore Epidemiologic Catchment Area
study surveyed in 1980 and followed through 1994–1995. They were assessed for depressive and
anxious disorders, paternal death in childhood and relatively recent adverse life events prior to
cancer hospitalization.Results. In the course of the study, 29 women were hospitalized for breast cancer and 10 died of
breast cancer. The psychosocial variables that predicted increased risk of breast cancer were
maternal death in childhood (OR = 2·56, P < 0·001) and chronic depression with severe episodes
(OR = 14·0, P < 0·001). Neither relatively recent life events nor other depressive and anxiety
disorders were associated with increased risk. Maternal death and chronic depression with severe
episodes were reported to have occurred at least 20 years prior to breast cancer hospitalization.Conclusions. Maternal death and chronic and severe depression occurred at least 20 years prior to
breast cancer hospitalization and could have been involved in the causation or facilitation of cancer
development. The authors suggest that meta-analysis of other prospective studies are needed to
create larger groups of individuals with these stresses to confidently establish these variables as risk
factors.
On the ergodic properties of Cartan flows in ergodic
actions of ${\bf SL}_{\bf 2}{\bf (R)}$ and ${\bf SO}{\bf ({\bi n},1)}$
Authors: FURMAN ALEX , WEISS BENJAMIN 
Published: July 2002

Let $G={\rm SL_2({\bf R})}$ (or $G={\rm SO}(n,1)$) act ergodically on a
probability space $(X,m)$.
We consider the ergodic properties of the flow $(X,m,\{g_t\})$, where
$\{g_t\}$ is a Cartan subgroup of $G$.
The geodesic flow on a compact Riemann surface
is an example of such a flow; here
$X=G/\Gamma$ is a transitive $G$-space, $G={\rm SL_2({\bf R})}$ and
$\Gamma\subset G$
is a lattice. In this case the flow is Bernoullian.For the general ergodic $G$-action, the flow $(X,m,\{g_t\})$
is always a $K$-flow, however there are examples
in which it is not Bernoullian.
AWE experimental laser plasma program
Authors: DUNNE M. , EDWARDS J. , GRAHAM P. , EVANS A. , ROTHMAN S. , SMEDLEY-STEVENSON R. , BARNES C.W. , HSING W. , GOLDMAN S.R. 
Published: July 2002

The achievement of ignition from an Inertial Confinement
Fusion capsule will require a detailed understanding of
a wide range of high energy density phenomena. This paper
presents some recent work aimed at improving our knowledge
of the strength and equation of state characteristics of
low-Z materials, and outlines data which will
provide quantitative benchmarks against which our predictive
radiation hydrodynamics capabilities can be tested. Improvements
to our understanding in these areas are required if reproducible
and predictable fusion energy production is to be achieved
on the next generation of laser facilities.In particular, the HELEN laser at AWE has been used to create
a thermal X-ray source with 140 eV peak radiation temperature
and 3% instantaneous flux uniformity to allow measurements
of the Equation of State of materials at pressures up to
20 Mbar to an accuracy of <±2% in shock velocity.
The same laser has been used to investigate the onset of
spallation upon the release of a strong shock at a metal-vacuum
boundary, with dynamic radiography used to image the spalled
material in flight for the first time. Finally, a range
of experiments have been performed to generate quantitative
radiation hydrodynamics data on the evolution of gross
target defects, driven in both planar and imploding geometry.
X-ray radiography was used to record the evolving target
deformation in a system where the X-ray drive and unperturbed
target response were sufficiently characterized to permit
meaningful analysis. The results have been compared to
preshot predictions made using a wide variety of fluid
codes, highlighting substantial differences between the
various approaches, and indicating significant discrepancies
with the experimental reality. The techniques developed
to allow quantitative comparisons are allowing the causes
of the discrepancies to be identified, and are guiding
the development of new simulation techniques.
Conference Reports
Authors: Lederman Susan J. , Howe Robert D. 
Published: July 2002

SIXTH ANNUAL SYMPOSIUM ON HAPTIC INTERFACESThe Sixth Annual Symposium for Haptic Interfaces for Virtual Environment and Teleoperator Systems was held on Nov. 17–18, 1997 in Dallas, Texas. Haptic interfaces
are devices that allow human–machine interaction through force and touch.
Areas of application include, but are by no means limited, to telemanipulation (for work in hazardous or challenging environments such as space exploration, undersea operations, microsurgery and minimally-invasive surgery, and hazardous waste clean-up) and virtual environments (for realistic interactions with computer simulations in critical procedure training, architectural design, product prototyping, and data visualization).
A COMPARISON OF THREE APPROACHES FOR ATTRIBUTING HOSPITALIZATIONS TO
SPECIFIC DISEASES IN COST ANALYSES
Authors: Ward Marcia M. , Javitz Harold S. , Smith W. McFate , Bakst Alan 
Published: July 2002

Objectives: Calculations of healthcare costs rarely disclose the
specific approach used to allocate the cost of hospitalizations by diagnosis.
However, the type of approach used can have a major impact on the findings in
the case of significant comorbidities. The present analyses compared three
approaches for attributing Medicare DRG reimbursements (which were used as
surrogates for average costs) for hospitalization by diagnosis.Methods: Medical resource utilization data from the National
Hospital Discharge Survey were analyzed using each of three allocation
approaches: a) attributing 100% of the cost of hospitalization to the disease
when it was the first-listed diagnosis; b) attributing a portion of the cost
of hospitalization to the disease, depending on its position in the list of
diagnoses and the relevance of any comorbidities; and c) an incremental
analysis of cost based upon the hospitalization experiences of an age and
gender matched cohort. These three approaches were applied to the cost of
hospitalization for chronic obstructive pulmonary disease (COPD).Results: The first approach projected 206,098 hospitalizations at
$3,449 per hospitalization for a projected U.S. annual total of $711 million.
The second approach projected 681,547 hospitalizations at $3,205 per
hospitalization for a projected U.S. annual total of $2.2 billion. The third
approach also projected 681,547 hospitalizations, but at $2,361 per
hospitalization, for a projected U.S. annual total of $1.6 billion.Conclusions: Expanding from the example on COPD, the limitations
of each approach are described and their applications to other conditions are
presented.
How far does a construction grammar approach to
argument structure take us in understanding
children's language development?
Authors: BUDWIG NANCY 
Published: July 2002

Tomasello's stimulating review of Goldberg's (1995)
book, Constructions: a
construction grammar approach to argument structure, raises several
themes
worthy of discussion. Tomasello suggests numerous reasons why functional

and cognitive linguistic approaches in general, and Goldberg's approach
in
particular, are central to current work in child language. In my commentary

I will summarize Tomasello's central claims about what he sees as
significant
about Goldberg's book, and I will raise the question of whether construction

grammar – rather than any other cognitive or functional approach
– is worth
pursuing. While generally sympathetic to Goldberg's approach, I will

discuss two issues that I think are worthy of further consideration in
future
research.Tomasello highlights three very important reasons why he believes
Goldberg's approach makes a significant contribution to child language

research. First, he states that construction grammar provides a way of

understanding language development as a whole, and not just particular

aspects of language development, such as core grammar. Second, Tomasello

characterizes Goldberg's approach as noteworthy because it provides
a way
of relating language development to other domains of human cognition. A

third advantage, Tomasello claims, is that construction grammar allows
for
the view of language development as protracted (e.g. not instantaneous),

something Tomasello suggests fits well with his own research findings (see

Tomasello, 1992).
Augmentation as affixation in Athabaskan languages
Authors: Hargus Sharon , Tuttle Siri G. 
Published: July 2002

Athabaskan languages display a remarkable cross-language similarity,
yet
at the same time the languages of this family differ from each other in
restricted ways. This unity and variety provide a useful laboratory for
phonological and morphological research. In this paper, we suggest that
a
certain case of unity which has been analysed as phonologically and
morphologically motivated requires a purely morphological analysis.The case in question is the well-known verbal disyllabic minimality
requirement, which has been variously analysed as satisfaction of a
disyllabic verb template (Slave; Rice 1990), satisfaction of a monosyllabic
prefix-based portmanteau ‘stem’ (Navajo; McDonough 1990, 1996)
or
the result of stray consonant syllabification in the Minimal Word domain
in verbs (Ahtna; Causley 1994). However, when data from other languages
of the family are brought into the picture, a different, family-wide analysis
suggests itself.
A Low-CO2-Inducible Gene Encoding an Alanine:α--Ketoglutarate Aminotransferase in Chlamydomonas reinhardtii
Authors: Chen Z. Y. , Burow M. D. , Mason C. B. , Moroney J. V. 
Published: July 2002

Abstract
At low-CO2 (air) conditions, the unicellular green alga Chlamydomonas reinhardtii acquires the ability to raise its internal inorganic carbon concentration. To study this adaptation to low CO2, cDNA clones induced under low-CO2 growth conditions were selected through differential screening. One full-length clone is 2552 bp, with an open reading frame encoding 521 amino acids. The deduced amino acid sequence shows about 50% identity with alanine:α--ketoglutarate aminotransferase (Ala AT, EC 2.6.1.2) from plants and animals, and the mRNA of this clone increased 4- to 5-fold 4 h after cells were switched from high-CO2 to low-CO2 growth conditions. The expression of the enzyme and its activity also increased accordingly at low-CO2 growth conditions. To study the physiological role of Ala AT, a pyridoxal phosphate inhibitor, aminooxyacetic acid, was added at 40 [mu]M to the growth medium when cells were beginning to adapt to low CO2. This caused a 30% decrease in the maximum photosynthetic rate in air-adapting cells 8 h later. The addition of the inhibitor also caused the cells to excrete glycolate, a photorespiratory intermediate, but did not change the apparent affinity of the cell for external CO2. These physiological studies are consistent with the assumption that Ala AT is involved in the adaptation to low-CO2 conditions.