bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct numerical simulation of a confined
three-dimensional gas mixing layer with one
evaporating hydrocarbon-droplet-laden stream
Authors: MILLER R. S. , BELLAN J.
Published: July 2002

Direct numerical simulations are performed of a confined three-dimensional,

temporally developing, initially isothermal gas mixing layer with one stream
laden with
as many as 7.3×105 evaporating hydrocarbon droplets, at
moderate gas
temperature and subsonic Mach number. Complete two-way phase couplings
of mass, momentum
and energy are incorporated which are based on a thermodynamically self-consistent

specification of the vapour enthalpy, internal energy and latent heat of
vaporization.
Effects of the initial liquid mass loading ratio (ML),
initial Stokes number (St0),
initial droplet temperature and flow three-dimensionality on the mixing
layer growth
and development are discussed. The dominant parameter governing flow modulation

is found to be the liquid mass loading ratio. Variations in the initial
Stokes number
over the range 0.5[les ]St0[les ]2.0 do not cause
significant modulations of either first- or
second-order gas phase statistics. The mixing layer growth rate and kinetic
energy are
increasingly attenuated for increasing liquid loadings in the range
0[les ]ML[les ]0.35.
The laden stream becomes saturated before evaporation is completed for
all but the
smallest liquid loadings owing to: (i) latent heat effects which reduce
the gas temperature,
and (ii) build up of the evaporated vapour mass fraction. However, droplets

continue to be entrained into the layer where they evaporate owing to contact
with the
relatively higher-temperature vapour-free gas stream. The droplets within
the layer
are observed to be centrifuged out of high-vorticity regions and to migrate
towards
high-strain regions of the flow. This results in the formation of concentration
streaks
in spanwise braid regions which are wrapped around the periphery of secondary

streamwise vortices. Persistent regions of positive and negative slip velocity
and slip
temperature are identified. The velocity component variances in both the
streamwise
and spanwise directions are found to be larger for the droplets than for
the gas
phase on the unladen stream side of the layer; however, the cross-stream
velocity and
temperature variances are larger for the gas. Finally, both the mean streamwise
gas
velocity and droplet number density profiles are observed to coincide for
all ML when
the cross-stream coordinate is normalized by the instantaneous vorticity
thickness;
however, first-order thermodynamic profiles do not coincide.
The effects of rotation on axisymmetric gravity currents
Authors: UNGARISH MARIUS , HUPPERT HERBERT E.
Published: July 2002

Axisymmetric gravity currents in a system rotating around a vertical
axis, that
result when a dense fluid intrudes horizontally under a less dense ambient
fluid, are
studied. Situations for which the density difference between the fluid
is due either to
compositional differences or to suspended particulate matter are considered.
The fluid
motion is described theoretically by the inviscid shallow-water
equations. A ‘diffusion’
equation for the volume fraction in the suspension is derived for the particle-driven

case, and two different models for this purpose are presented. We focus
attention
on situations in which the apparent importance of the Coriolis terms relative
to the
inertial terms, represented by the parameter [Cscr ] (the inverse of a Rossby
number),
is not large. Numerical and asymptotic solutions of the governing equations
clarify
the essential features of the flow field and particle distribution, and
point out the
striking differences from the non-rotating case (Bonnecaze, Huppert &
Lister 1995).
It is shown that the Coriolis effects eventually become dominant; even
for small
[Cscr ], Coriolis effects are negligible only during an initial period of
about one tenth
of a revolution. Thereafter the interface of the current acquires a shape
which has
a downward decreasing profile at the nose and its velocity of propagation
begins
to decrease to zero more rapidly than in the non-rotating situation. This
relates
the currents investigated here to the previously studied quasi-steady oceanographic

structures called rings, eddies, vortices or lenses, and may throw additional
light on the
dynamics of their formation. The theoretical results were tested by some
preliminary
experiments performed in a rotating cylinder of diameter 90 cm filled with
a layer of
water of depth 10 cm in which a cylinder of heavier saline fluid of diameter
9.4 cm
was released.
Flow-induced instabilities of a mucus–serous bilayer
Authors: MORIARTY J. A. , GROTBERG J. B.
Published: July 2002

In this paper we investigate the stability of a bilayer exposed to air flow. The bilayer
consists of a viscoelastic solid layer (mucus), which rests on a viscous fluid film
(serous fluid). The motivation behind this work is to examine the coupled, fluid/elastic
instabilities related to mucus clearance in the lung where breathing and cough apply
shear forces from the air flow onto the bilayer. Previous research on mucus transport
due to air flow has not addressed the effects of the underlying serous layer nor those
of surface tension at the mucus–air interface, two new features incorporated into the
model. Surface tension effects are governed by the new parameter
κ′ = (σ/dG′) where
σ is the air–mucus surface tension, G′ is the elastic shear modulus of the mucus, and
d is a characteristic thickness of the bilayer. The model predictions for the onset of
unstable waves as a function of the parameters are compared to previous theories
and experiments to provide physical interpretations and to compare results. The
comparison with experiments show good qualitative and quantitative agreement. The
results are compared, also, to flow over a single, viscoelastic layer, with no viscous
fluid underneath, to demonstrate the appearance of new wave behaviour when the
viscous fluid is added.
Three-dimensional double-diffusive convection
in a porous cubic enclosure due to opposing
gradients of temperature and concentration
Authors: SEZAI I. , MOHAMAD A. A.
Published: July 2002

A three-dimensional mathematical model based on the Brinkman extended Darcy
equation has been used to study double-diffusive natural convection in a fluid-saturated porous cubic enclosure subject to opposing and horizontal gradients of
temperature and concentration. The flow is driven by conditions of constant temperature
and concentration imposed along the two vertical sidewalls of the cubic enclosure,
while the remaining walls are impermeable and adiabatic. The numerical simulations
presented here span a wide range of porous thermal Rayleigh number, buoyancy
ratio and Lewis number to identify the different steady-state flow patterns and bifurcations.
The effect of the governing parameters on the domain of existence of the
three-dimensional flow patterns is studied for opposing flows (N < 0). Comprehensive
Nusselt and Sherwood number data are presented as functions of the governing
parameters. The present results indicate that the double-diffusive flow in enclosures
with opposing buoyancy forces is strictly three-dimensional for a certain range of
parameters. At high Lewis numbers multiple dipole vortices form in the transverse
planes near the horizontal top and bottom surfaces, which the two-dimensional models
fail to detect. The dipolar vortex structures obtained are similar to those created
in laboratory experiments by the injection of fluid into a stratified medium.
Depth in English grammar
Authors: SAMPSON GEOFFREY
Published: July 2002

Corpus data are used to investigate Yngve's claim that

English usage avoids

grammatical structures in which the number of left branches between any
word and

the root node of a sentence exceeds some fixed limit. The data do display
a marked

bias against left-branching, but the pattern of word-depths does not conform
to

Yngve's concept of a sharp limit. The bias could alternatively

reflect a statistical

invariance in the incidence of left-branching, but whether this is so depends
on how

left-branching is counted. Six nonequivalent measures are

proposed; it turns out that

one (and only one) of these yields strikingly constant figures

for left-branching in real-life sentences over a wide

range of lengths. This is not the measure suggested by

Yngve's formulation; it is the measure whose invariance is arguably
the most

favourable for computational tractability.
The phonology of tone and intonation in the
Dutch dialect of Venlo
Authors: GUSSENHOVEN CARLOS , VAN DER VLIET PETER
Published: July 2002

The Dutch dialect of Venlo has a lexical tone opposition comparable to the
distinction between Accent I and Accent II in Scandinavian. The two word tone
patterns are realised in a variety of different ways, depending on the intonation
contour, on whether the word has a focus tone, and on whether it occurs finally or
nonfinally in the intonational phrase (IP). Twelve such contexts are identified, and an
autosegmental-metrical analysis is presented of the contours for the word tones in
each of these. The analysis is instructive because of its clear illustration of the
distinction between the phonological underlying representation and the phonological
surface representation, as well as of the distinction between the latter representation
and the phonetic realisation. In addition, because of the complexity of its tonal
phonology, the dialect is of considerable typological interest for the study of word
prosody and intonation.
The intrinsic relation between envelope solitons and plasma instabilities
Authors: HUANG GUANGLI
Published: July 2002

A general form of the one-dimensional nonlinear Schrödinger
equation is derived; the coefficients depend mainly on the linear dispersion
relation, as does the nonlinear term. Envelope solitons may only exist together
with some plasma instabilities. An example of solar radio bursts is selected as
evidence for envelope solitons in the electromagnetic waveband.
Numerical analysis of self-generated magnetic
field excited by transverse plasmons in a
laser-produced plasma
Authors: LIU S. Q. , LI X. Q.
Published: July 2002

Abstract. We study numerically the collapse behavior of self-generated magnetic
fields described by the nonlinear coupling equations in laser-produced plasmas.
The results show that magnetic fields self-generated by transverse pumping plasmons
near critical points may collapse, leading to the enhancement of magnetic
fields about up to 0.18 MG and 1.8 MG at laser irradiances of 1012 W cm−2 and
1016 W cm−2 respectively, which are similar to the experimental results.
Thermal conduction in strongly coupled plasmas: especially liquid
alkali metals
Authors: MARCH N. H. , TOSI M. P.
Published: July 2002

In earlier work, we have noted on semi-empirical grounds that the
electrical
conductivity σ in strongly coupled plasmas can be written as a linear
form
σ=σ0Γ in terms of the usual plasma coupling
parameter
Γ. Here, this is
combined with the Wiedemann–Franz law to yield a zeroth-order treatment
of
thermal conductivity κ in such strongly coupled plasmas. Some refinement
is
needed to explain the properties of the heavier liquid alkali metals beginning
with Na. This refinement follows from the nearly free-electron theory of
electrical resistivity ρ=σ−1. Finally, a relation
is forged between ρ, κ and the
shear viscosity η at the freezing point of liquid alkali metals.
Stimulated Raman, Brillouin and
dust–Brillouin scattering in dusty plasmas
Authors: GUERRA R. , MENDONÇA J. T. , SHUKLA P. K.
Published: July 2002

Stimulated scatterings of large-amplitude electromagnetic waves
by Langmuir,
dust–ion-acoustic and dust-acoustic waves in unmagnetized dusty plasmas
are
investigated by employing the standard methods of nonlinear three-wave
interactions
and by incorporating the effects of grain-charge fluctuations, collisions
of electrons
and ions with dust grains, the plasma drag on a dust grain (for the case
of the
dust-acoustic wave) and the dependence of the average dust charge on the
dusty
plasma parameters. Distinction is made between the charging collisions,
when electrons
and ions are accumulated onto the grain surface; and Coulomb collisions,

when electrons and ions are simply deflected from the grain surface. We
investigate
the regimes for which Coulomb collisions can be treated under the small-angle-deflection

approximation. If the intergrain average spacing is equal to or smaller

than the Debye length, the collision frequencies of plasma species with
dust grains
can be much larger than any collision frequency of the plasma species amongst

themselves. In the case of Brillouin stimulated scattering, other important
contributions
to damping come from Landau and dust-charge fluctuation damping. In
the case of dust–Brillouin stimulated scattering, the most important
contribution
to damping comes from dust-charge fluctuation (if the intergrain average
spacing
is equal to or smaller than the Debye length) and plasma drag on the dust
particles
(if the intergrain average spacing is larger than the Debye length). We
derive the
instability thresholds as a function of the density of the dust grains.
Because of the
inclusion of the new effects, in both Raman and Brillouin scatterings it
is found that
the instability threshold powers are drastically increased relative to
the dust-free
case. In the case of dust–Brillouin scattering, a minimum for the
threshold power is
found in the transition region between ‘dusty’ and
‘dust-in’ plasma. Growth rates near thresholds are also discussed.
Dynamics of hot filaments in a tokamak plasma
Authors: DE STERCK H. , POEDTS S. , GOEDBLOED J. P.
Published: July 2002

The reaction of an equilibrium tokamak plasma to a sudden localized
deposition
of heat is investigated by means of numerical simulations of the time-dependent

equations of resistive magnetohydrodynamics (MHD) in two spatial dimensions,

in order to obtain a better understanding of the structure and dynamics
of the
hot plasma filaments that are observed in recent tokamak experiments. Simulation

results show that the fast heating generates MHD waves and creates a localised

hot filament. Pressure perturbations are carried away from the heated area
by
slow waves, even when the heating is applied on the Alfvén time
scale. When a
temperature-dependent resistivity is considered, a current peak is formed
at the
place of the temperature peak, and the order of magnitude of the current
is given
by the condition that ηJz is constant.

Next to the wave dynamics, the simulations
show another type of hot filament dynamics caused by j×B
forces. These forces
drive filaments to the centre of the plasma at a nearly constant velocity,
which
decreases for smaller resistivities. Two filaments can merge under the
influence of
this current–current interaction. This process happens on a very
long time scale. For
realistic tokamak resistivities, the coalescence of filaments may take
place on time
scales of the order of the experimentally reported lifetime of filaments,
and may
thus be the mechanism that determines the lifetime of the filamentation
process.
Semigroup representation of the Vlasov evolution
Authors: PRIGOGINE I. , PETROSKY T.
Published: July 2002

The well-known van Kampen–Case treatment of the Vlasov equation
leads to a
spectrum on the real axis. In this paper we show that, by going to a ‘rigged’

Hilbert space, we can derive a spectral representation that is complex
and breaks time
symmetry. This leads to a semigroup description in which the decay rates
due to the
Landau damping appear explicitly in the spectrum. Moreover, we can then
define
an entropy. In this way, the relation between Landau damping and irreversibility

is made explicit. The analogy with the well-known Friedrichs model is stressed.
Individual variation in competitive performance of juvenile cod and its consequences for growth
Authors: Hart Paul J.B. , Salvanes Anne Gro V.
Published: July 2002

This communication reports on experiments, which studied the variation in competitive performance of juvenile cod (Gadus morhua L.) and their growth rates. The fish were held in groups of five in either summer or winter conditions and tested for their individual response to prey offered sequentially. There was marked individual variability. Fish that took the highest share of prey tended also to be those that took prey earlier than others. In winter conditions these fish were the largest, but in summer conditions size had no effect. There was a positive influence of the indices of competitive performance on individual growth rate but the relationship was not significant
The reproductive cycle of the sea urchin Psammechinus miliaris (Echinodermata: Echinoidea) in a Scottish sea loch
Authors: Kelly Maeve S.
Published: July 2002

The sea urchin Psammechinus miliaris was sampled at monthly intervals from two replicate sites at contrasting locations (littoral and subtidal habitats) on the west coast of Scotland. Samples were collected from November 1995 to October 1997. A study of gonad development showed a clearly defined annual cycle of gametogenesis with a single spawning period. Gonad indices (GIs) varied between locations, between sites at the same location and between study years. Gonad indices were maximal prior to the onset of the spawning period in June and July. Ripe gametes were shed by dissected urchins from June to September in 1996 and June to August in 1997 coinciding with the time of year when the gonad colour was best in terms of what is desired in the market place. Over winter the GIs were very low and gonads became very dark in colour. Higher summer GIs in the urchins from one littoral site suggested that the urchins there had a seasonal influx of a more nutritious or more abundant food resource. Histological determination of the reproductive state showed that for these food-limited populations high GIs do equate with the spawning period. The gametogenic cycle fits the six stage pattern described for other echinoid species. In females oocytes of various developmental stages were present throughout the annual cycle. Recruitment to the littoral location was monitored over two seasons by quantifying the number of urchins with a test diameter <5 mm appearing in the population. Recruitment appeared variable between sites and between seasons suggesting that the collection of juveniles resulting from natural settlement may not be a reliable alternative to hatchery produced spat. Although P. miliaris has commercial potential when in cultivation, this study provided no evidence of an opportunity for a commercial fishery.
Comparative study of putative conspecific sponge populations from both sides of the Isthmus of Panama
Authors: Boury-Esnault N. , Klautau M. , Bézac C. , Wulff J. , Solé-Cava A.M.
Published: July 2002

A morphological, cytological and genetic comparison of putative conspecific populations of Spirastrella sp. cf. mollis (Porifera: Demospongiae) from both sides of the Isthmus of Panama revealed a very high level of genetic differentiation together with morphological and cytological differences. The main differences were the distribution of the spirasters within the choanosome, the size and shape of spirasters 1, and the size and shape of inclusions within type I cells. Consequently these two populations clearly belong to different biological species. The Atlantic one, S. hartmani sp. nov. corresponds to what previous authors have called S. cunctatrix in the Caribbean. The finding of this new species raises to three the number of Spirastrella spp. known from the Caribbean Sea. The Pacific species is named here S. sabogae sp. nov. The levels of gene divergence found between S. hartmani and S. sabogae (Nei's genetic distance D=2.30) were as high as those found between different genera in other groups of invertebrates. Similarly exceptionally high values of gene divergence have been found between other congeneric sponge species and may be indicative either of a higher rate of molecular evolution or a very slow rate of morphological evolution in the Porifera compared to other metazoans.
Duration of refuge residence by goldsinny, Ctenolabrus rupestris
Authors: Sayer M.D.J.
Published: July 2002

The duration of residence at identifiable refuges in separate territories was assessed over an 800-d period for the goldsinny, Ctenolabrus rupestris, a territorial labrid (Osteichthyes: Perciformes: Labridae), on the west coast of Scotland. Goldsinny (N=12; seven male, five female) were taken from, tagged and returned to, marked refuges using anaesthetics applied underwater. Over the whole study period two goldsinny (one male, one female) moved between adjoining territories, but most (eight out of the ten recaptured or observed) remained in the refuge in which they were released.
Reproductive biology of two deep-water sharks from the British Isles, Centroscymnus coelolepis and Centrophorus squamosus (Chondrichthyes: Squalidae)
Authors: Girard Marine , Du Buit Marie-Henriette
Published: July 2002

The reproductive biology of two aplacental viviparous deep sea sharks, Centroscymnus coelolepis and Centrophorus squamosus has been studied from 1735 and 675 specimens respectively, collected with bottom trawls between 600 and 1400 m depth off the west coast of the British Isles. A macroscopic maturity scale indicates that for both species, size at first maturity is greater in females than in males. In Centroscymnus coelolepis, genital maturity occurs at an average length of ∼86 cm for males and ∼102 cm for females. In Centrophorus squamosus, males are mature near 98 cm and females near 124 cm total length (TL). Smallest juveniles of both species are absent from catches: no specimens of Centroscymnus coelolepis shorter than 58 cm, nor specimens of Centrophorus squamosus shorter than 84 cm have been recorded. Ovarian fecundity is higher in Centroscymnus coelolepis than in Centrophorus squamosus. A maternal supply has been demonstrated for Centroscymnus coelolepis. Litter size has been estimated only in C. coelolepis because no pregnant females of Centrophorus squamosus were recovered. A dwarf embryo and a pair of twins have been observed. Segregation by sexual stage of development shows that immatures are generally found at greater depths than adults.
A multiple gestation in a Delphinus delphis stranded on the north-western Spanish coast
Authors: González Angel F. , López Alfredo , Benavente Pedro
Published: July 2002

The present study is the first record of twinning in Delphinus delphis. The first foetus was a female of 72 cm total length which had a curved caudal area. This animal was located in the left uterine horn, very close to the genital aperture. The second foetus was a male of 46 cm total length and its external morphology was deformed. It was located in the uterus and the nose was shorter than the female foetus. Documented incidences of twinning in cetaceans are rare.
Japanese Writer in Vietnam: The Two Wars of Kaiko Ken (1931-89)
Authors: POWELL IRENA
Published: July 2002

Our image and knowledge of the Vietnam war come predominantly from American sources, which all stress the unusual character of that war. From the despatch of the first combat units to Vietnam in 1960 to the fall of Saigon and the takeover by the North Vietnamese in 1975, it was America's longest war. American literature from Vietnam depicts the war as being waged not only against the enemy (particularly as it was often difficult to determine who and where the enemy was) but also against the elements — heat, rain, jungle, mosquitoes, leeches, dust and mud. The moral confusion surrounding this war and the disillusionment among the soldiers are well documented and portrayed in numerous films and stories. In examining, therefore, Japanese writing on the Vietnam war, it seemed sensible to concentrate on those aspects which were different, not only in order not to repeat the obvious, but also in the hope of bringing into focus the different perspective on the conflict which this writing offers.
Necator americanus in inbred mice: evidence in support of
genetically determined differences in the cellular immune response to a
primary infection
Authors: TIMOTHY L. M. , BEHNKE J. M.
Published: July 2002

The blood and broncho-alveolar leucocyte (BAL) responses, to a
primary Necator americanus infection, were studied in male BALB/c
and NIH mice. Following percutaneous infection, a significant blood leucocytosis
occurred in both the BALB/c and NIH strains. The peak response occurred,
in both strains, on day 10 p.i. and this was reflected in the eosinophil
response which peaked at the same time-point. The change in blood eosinophil
numbers, as a result of infection, was found to be the greatest recorded
for any cell type. In BALB/c mice, however, infection elicited a significantly
more intense total leucocyte, lymphocyte and eosinophil response than in
NIH mice. In contrast, the BAL response was more intense in the NIH strain.
Peak BAL responses were observed between days 12 and 16 p.i., in both strains,
and the change in broncho-alveolar eosinophil numbers, as a result of infection,
was found to be the greatest recorded for any cell type. The relationship
between the observed leucocyte responses and resistance to the migrating
larvae of a primary infection is discussed.
Mixed-genotype infections of the rodent malaria
Plasmodium chabaudi are more infectious to mosquitoes
than single-genotype infections
Authors: TAYLOR L. H. , WALLIKER D. , READ A. F.
Published: July 2002

Interactions between parasite genotypes sharing a host are poorly
understood, but have important consequences for the
epidemiology and evolution of the parasite. In mixed-genotype malaria
infections, patterns of asexual replication and
transmission favoured by natural selection may be different from those
in single-genotype infections. The infectivity to
mosquitoes of mixed-genotype and single-genotype infections were compared
using 2 clones of Plasmodium chabaudi
inoculated into mice either together or alone. Mice given mixed-clone
infections received the sum of the inocula given to
the single-clone controls. Mosquitoes were fed on the mice and the numbers
of oocysts which developed were counted
to assess transmission intensity. For 3 combinations of starting inocula
and feed days, mixed-clone infections produced
more oocysts per mosquito than the sum of the 2 single-clone infections.
This effect was correlated with an increase in
gametocyte density, but was less clearly related to asexual infection
parameters. The results show that interactions between
clones in mixed-clone infections can profoundly affect transmission.
Schistosoma mansoni sporocysts contain rhodoquinone and
produce succinate by fumarate reduction
Authors: VAN HELLEMOND J. J. , VAN REMOORTERE A. , TIELENS A. G. M.
Published: July 2002

Although schistosomes were thought to be one of the few parasitic
helminths that do not produce succinate via fumarate
reduction, it was recently demonstrated that sporocysts of Schistosoma
mansoni produce, under certain conditions,
succinate in addition to lactate. This succinate production was only observed
when the respiratory chain activity of the
sporocysts was inhibited, which suggested that succinate is produced by
fumarate reduction. In this report the presence
of essential components for fumarate reduction was investigated in various
stages of S. mansoni and it was shown that, in
contrast to adults, sporocysts contained a substantial amount of
rhodoquinone which is essential for efficient fumarate
reduction in eukaryotes. This rhodoquinone was not made by modification
of
ubiquinone obtained from the host, but was
synthesized de novo. Furthermore, it was shown that complex II
of
the electron-transport chain in schistosomes has the
kinetic properties of a dedicated fumarate reductase instead of those of
a
succinate dehydrogenase. The presence of such
an enzyme, together with the substantial amounts of rhodoquinone, shows
that in
S. mansoni sporocysts succinate is
produced via fumarate reduction. Therefore, the energy metabolism of
schistosomes does not differ in principle from most
other parasitic helminths, which are known to rely heavily on fumarate
reduction.
Leishmania amazonensis promastigotes evade complement

killing by interfering with the late steps of the cascade
Authors: NUNES A. C. , ALMEIDA-CAMPOS F. R. , HORTA M. F. , RAMALHO-PINTO F. J.
Published: July 2002

During their growth in vitro, promastigotes of Leishmania

amazonensis undergo differentiation from complement-susceptible to

complement-resistant forms. Here, we demonstrate that both forms bind

comparable amounts of C3 on their

surfaces, with the predominant molecule species being the haemolytically

active C3b. Likewise, equivalent amounts of C9

are deposited on both forms of promastigotes. However, while C9-bearing

complexes are exposed on the cell surface of

resistant promastigotes, they are cryptic in the susceptible stage of the

parasites. The membrane fraction of complement-resistant promastigote

lysates has the ability to inhibit complement-mediated haemolysis,

blocking C9, but not C3

deposition to complement-activating complexes. Moreover, the membrane

fraction of complement-resistant promastigote

lysates can inhibit the late steps of guinea-pig erythrocyte lysis much
more

efficiently than complement-susceptible ones.

Our results indicate that L. amazonensis promastigotes evade

complement killing by inhibiting the cytolytic pathway of

the complement cascade.
Flow cytometric assessment of oxidant stress in age-fractionated
thalassaemic trait erythrocytes and its
relationship to in vitro growth of Plasmodium falciparum
Authors: SENOK A. C. , LI K. , NELSON E. A. S. , ARUMANAYAGAM M. , LI C. K.
Published: July 2002

The role of oxidant stress in mediating the protection
against malaria in thalassaemic red blood cells (RBC) has been
hypothesized. In this study we have assessed the relationship
between oxidant stress, red cell age and malarial parasite
activity in thalassaemic RBC. Using a flow cytometric method to assess
lipid peroxidation, we have shown that the age-related increase
in sensitivity to oxidative stress previously demonstrated in normal
RBC also occurs in thalassaemic RBC.
Invasion and growth of Plasmodium falciparum was also shown
to deteriorate with increasing RBC age. This effect was
more pronounced in thalassaemic RBC with associated schizont
maturation arrest and abnormal parasite morphology. In
addition, there was a slight but consistent inverse correlation
between sensitivity to oxidant stress and parasite activity
(R=−0·43; P=0·03 for normal RBC
and R=−0·42; P=0·01 for
thalassaemic RBC). Our findings indicate an
association between red cell age, oxidant stress and
P. falciparum growth, providing further support for the
role of oxidant stress in mediating the protective effect against
malaria in thalassaemic RBC.
Spatial and temporal distributions of parasites: can wild
and domestic ungulates avoid African tick larvae?
Authors: DE GARINE-WICHATITSKY M. , DE MEEÛS T. , GUÉGAN J.-F. , RENAUD F.
Published: July 2002

Infestation of a new host is a crucial stage in the life-cycle of parasites, and the possibility that hosts avoid infesting contact
depends, in part, on the predictability of infestation risk. Immature free stages of ticks (Acari, Ixodidae) have limited
mobility and survival in the vegetation and strongly depend on host behaviours for their infestation. We studied spatial
and temporal distributions of the larvae of 2 major groups of African tick species in a ranch in Zimbabwe. No difference
in the abundance of Rhipicephalus evertsi evertsi larvae was found among vegetation types and during most of the seasonal
cycle, and no reliable indicator of their presence on a given site was identified. Rhipicephalus appendiculatus/Rhipicephalus
zambeziensis larvae are mainly found during the cool dry season, in vegetation types situated close to permanent water
holes or dominated by Acacia trees, which provide key forage resources for ungulates; and several indicators of their
presence were identified. For both tick groups, spatial and temporal distributions of the larvae result in an optimized
contact with ungulate hosts: R. e. evertsi larvae are unpredictable and thus unavoidable by hosts, whereas R.
appendiculatus/R. zambeziensis larvae are predictable but also unavoidable because they are associated with key-resources for
ungulates.
Predation of beetles (Tenebrio molitor) infected with
tapeworms (Hymenolepis diminuta): a note of caution for
the Manipulation Hypothesis
Authors: WEBSTER J. P. , GOWTAGE-SEQUEIRA S. , BERDOY M. , HURD H.
Published: July 2002

Previous laboratory studies have indicated that tenebrionid beetles infected with Hymenolepis diminuta display behavioural
alterations. These are assumed to increase the likelihood of this intermediate host being predated by the Rattus sp.
definitive host, and hence provide support for the Manipulation Hypothesis. We tested this hypothesis by both assessing
beetle behaviour and predation rates in semi-naturalistic environments. Behavioural assays showed that infected beetles
were more often exposed (not concealed under boxes) than uninfected beetles. However, there were no differences in
predation rates between infected and uninfected beetles. We discuss this in terms of the historical and evolutionary contexts
under which such altered behaviours could evolve and their implications for the Manipulation Hypothesis.
Molecular and phylogenetic analysis of
Cryptosporidium muris from various hosts
Authors: MORGAN U. M. , XIAO L. , MONIS P. , SULAIMAN I. , PAVLASEK I. , BLAGBURN B. , OLSON M. , UPTON S. J. , KHRAMTSOV N. V. , LAL A. , ELLIOT A. , THOMPSON R. C. A.
Published: July 2002

Isolates of Cryptosporidium muris and C. serpentis were characterized from different hosts using nucleotide sequence
analysis of the rDNA 18S and ITS1 regions, and the heat-shock (HSP-70) gene. Phylogenetic analysis confirmed
preliminary evidence that C. muris is not a uniform species. Two distinct genotypes were identified within C. muris; (1)
C. muris genotype A; comprising bovine and camel isolates of C. muris from different geographical locations, and (2) C.
muris genotype B comprising C. muris isolates from mice, a hamster, a rock hyrax and a camel from the same enclosure.
These 2 genotypes may represent separate species but further biological and molecular studies are required for
confirmation.
Plato's Quinean Beard: Did Plato ever grow it?
Authors: DURRANT MICHAEL
Published: July 2002

Quine may be taken to use the phrase ‘Plato's Beard’ to denote a solution to the following problem: How is it possible to speak of that which does not exist, of non-being or as Read has it, to denote a solution to the problem: ‘How can a sentence with empty names have meaning?’.

Quine writes:

Nonbeing must in some sense be, otherwise what is that there is not? This tangled doctrine might be nicknamed Plato's beard; historically it has proved tough, frequently dulling the edge of Occam's razor.

To expand. If nonbeing in no sense is, then we cannot ever assert that it is not; yet if it in some sense is, then how can it remain nonbeing? Let us fill out with an example (coined from Quine). If Pegasus in no sense exists, then how can we ever assert that Pegasus does not exist?—yet we may clearly want to assert that Pegasus does not exist and affirm the proposition that it is false that Pegasus exists. If, on the other hand, Pegasus in some sense exists, how may we affirm that he does not? We shall be contradicting ourselves or be guilty of equivocation.
A Critique of Elie Halévy
Authors: VERGARA FRANCISCO
Published: July 2002

The prestigious French publisher Presses Universitaires de France has recently brought out (November 1995) a new French edition of Elie Halévy's well known book The Growth of Philosophical Radicalism, first published in France in three volumes as La formation du radicalisme philosophique (1901–1904) and translated into English in 1926. The prevailing opinion on this book is that it gives an excellent account of English utilitarianism. Thus, in the International Encyclopedia of Social Sciences, Talcott Parsons speaks of it as the ‘virtually definitive analysis of utilitarianism’ More recently Donald Winch, in his introduction to the Penguin edition of John Stuart Mill's Principles of Political Economy, describes Halévy's book as: ‘Still the best study of the ideas and activities of the school taken as a whole’.

In this short essay I express a very different opinion. I show that Halévy, who qualifies utilitarianism (with obvious disgust) as ‘a plebeian or rather bourgeois morality’, as ‘much too simple’, completely misunderstood the writings of the English and Scottish utilitarian philosophers.

Halévy's understanding of Utilitarianism and the Principle of Utility

There is no clear or precise definition of utilitarianism in Halévy's book, but he obviously understood it to be a descriptive theory, and took the ‘principle of utility’ for a psychological law explaining human behaviour: ‘the fundamental principle of the doctrine is that pleasure is the natural end of human actions’, ‘The principle of utility [...] meant that all men naturally incline towards pleasure and flee from pain’.
The longer term outcomes of community care: a 12 year follow-up of the Camberwell High Contact Survey
Authors: REID Y. , JOHNSON S. , BEBBINGTON P. E. , KUIPERS E. , SCOTT H. , THORNICROFT G.
Published: July 2002

Background. There is as yet little evidence available regarding the long-term outcomes of people with severe and enduring mental illness who have been cared for primarily in the community.

Methods. A 12-year follow-up was carried out of the clinical and social problems and needs for care of a group of long-term mentally ill patients (N=81) who were heavy users of psychiatric services when originally assessed in the Camberwell High Contact Survey between 1983 and 1985. The MRC Needs for Care Assessment Schedule used in the original baseline study was repeated at follow-up.

Results. The clinical and social functioning of the group had remained relatively stable, with high levels of problems and needs at both time points and little evidence of significant improvement or deterioration. The majority had remained in contact with services. There was some increase in levels of unmet as well as met needs, and a decrease in ratings of unmeetable needs, which may have been due to changes in clinical practice.

Conclusion. The challenge for current service providers is not only to keep clients stable, but also to help improve the clinical and social functioning of people who may no longer be the highest priority of current community mental health services. This could be approached by identifying the continuing needs of this group, and persistently delivering active treatments.
The psychiatric after-effects of the Holocaust on the second generation
Authors: LEVAV I. , KOHN R. , SCHWARTZ S.
Published: July 2002

Numerous studies conducted in clinical and community settings by

researchers from different
countries over a period of almost five decades, have conclusively shown
protracted and disabling
psychiatric effects among World War II Holocaust victims, formerly known
as the concentration
camp syndrome (e.g. Matussek, 1975; Eitinger & Krell, 1985; Eitinger

& Major, 1993; Levav,
1998). The multiple and brutal trauma endured by the survivors during the
war years were further
compounded by earlier systematic discrimination, and by exhausting socio-political
events and
pogroms that followed liberation by the Allies. In this latter
period survivors had to learn the
fate of their spouses, children, parents, other relatives and friends.

Hastily contracted post-war
marriages were likely intended both to cope with feelings of extreme
loneliness and to recreate a social support group that would buttress survival.

Given the above, many observers hypothesized that, among other
impaired abilities, survivors
would evidence a deficit in their parenting functions. As one author
noted 25 years ago: ‘Survivors
are now beginning to bring their children to our clinics. In retrospect

one should not be surprised
at this because of the nature and severity of the psychological effects

of the persecution, and because
the emotional state of the parents has some bearing on the development

of the child …’ (Sigal,
1971). Several mediating mechanisms that affected the survivors'
family as a functioning unit were
postulated by the examining clinicians, such as over-involvement,
withdrawal, inability to exert
control, parental affective unavailability, undue degree of
preoccupation with past experiences, and
an inability to cope with mourning and bereavement (Klein, 1973;
Levine, 1982; Sigal & Weinfeld,
1989). Other imputed mechanisms referred to psychological processes taking
place during child
development, such as difficulties in the individuation-separation phase
(Freyberg, 1980).
Performance of children and adolescents with PTSD
on the Stroop colour-naming task
Authors: MORADI A. R. , TAGHAVI M. R. , NESHAT DOOST H. T. , YULE W. , DALGLEISH T.
Published: July 2002

Background. Investigators have used various experimental
paradigms such as the Stroop colour
naming test to study how adults with different emotional disorders process
emotional information.
However, to date, little research has been carried out on younger subjects.

Method. In the current experiment, children and adolescents
with post-traumatic stress disorder
(PTSD) and control subjects aged 9–17 years, participated in a modified
Stroop colour naming task.

Results. The results indicated that the children and adolescents
with PTSD showed increased Stroop
interference for trauma-related material relative to neutral words and
to the performance of the
controls.

Conclusions. These findings indicate that attentional bias
to trauma-congruent information is a
function of PTSD in young age groups. The results are discussed with respect
to the literature on
information processing in PTSD.
Urban–rural mental health differences in Great
Britain: findings from the National Morbidity Survey
Authors: PAYKEL E. S. , ABBOTT R. , JENKINS R. , BRUGHA T. S. , MELTZER H.
Published: July 2002

Background. Studies of urban–rural differences in prevalence of non-psychotic mental disorder
have not given consistent findings. Such differences have received relatively little study in Great
Britain.

Methods. Data from 9777 subjects in the Household Survey of the National Morbidity Survey of
Great Britain were analysed for differences between urban, semi-rural and rural areas. Psychiatric
morbidity was assessed by scores on the Revised Clinical Interview Schedule (CIS-R), together with
alcohol dependence, drug dependence, receipt of treatment from general practitioners. Associations
with other characteristics were examined by logistic regression.

Results. Urban subjects had higher rates than rural of CIS-R morbidity, alcohol dependence and
drug dependence, with semi-rural subjects intermediate. Urban subjects also tended to be members
of more deprived social groups, with more adverse living circumstances and greater life stress,
factors themselves associated with disorder. Urban–rural differences in alcohol and drug dependence
were no longer significant after adjustment for these factors by logistic regression, and differences
on CIS-R morbidity were considerably reduced. There were no differences in treatment.

Conclusions. There are considerable British urban–rural differences in mental health, which may
largely be attributable to more adverse urban social environments.
Early detection of Alzheimer's disease using the
Cambridge Cognitive Examination (CAMCOG)
Authors: SCHMAND B. , WALSTRA G. , LINDEBOOM J. , TEUNISSE S. , JONKER C.
Published: July 2002

Background. Dementia screening instruments, such as the Cambridge Cognitive Examination
(CAMCOG), measure a variety of cognitive functions. However, memory impairment generally is
the first sign of Alzheimer's disease (AD). It seems logical, therefore, to use only memory-related
items for the early detection of AD. We divided the CAMCOG into a memory section and a non-memory section, and tested the hypothesis that the memory section predicts AD better than the
non-memory section. We also provide normative data for both sections.

Methods. Normal subjects (N = 169) and patients with incident AD (i.e. satisfying AD criteria
between 1 and 3 years from baseline; N = 25) were participants in the Amsterdam Study of the
Elderly (AMSTEL), a population-based longitudinal study on cognitive decline and dementia.
Patients with prevalent AD (i.e. satisfying AD criteria at baseline; N = 155) were either recruited
in a memory clinic or came from AMSTEL. Normal subjects were cognitively intact at baseline and
remained so for at least 3 years. The CAMCOG was administered to all subjects. AD was diagnosed
by DSM-III-R criteria.

Results. Logistic regression analysis showed that the memory section was related to prevalent AD,
whereas in multivariate analysis the non-memory section was not (after correction for the memory
score and demographic characteristics). A similar analysis showed that the memory section
predicted incident AD, as did a higher score on the non-memory section. The MMSE did not
predict incident AD better than age alone.

Conclusion. For the early detection of AD it is best to use the memory and non-memory sections
separately instead of the total CAMCOG score.
Childhood sexual abuse and affective symptoms in women: a general population study
Authors: HILL J. , DAVIS R. , BYATT M. , BURNSIDE E. , ROLLINSON L. , FEAR S.
Published: July 2002

Background. Child sexual abuse (CSA) is associated, after controlling for other adversities, with a
range of non-psychotic disorders in adult life. There is a need to clarify whether CSA contributes
to risk of disorder in the absence of such adversities, and given that associations may be accounted
for by genetic mechanisms, whether they are seen where the perpetrator of CSA is not a biological
relative, and where there has been only one incident.

Methods. A questionnaire-based study of a socio-economically representative sample of women age
25–36 (N = 862) was carried out. Parental care and control were assessed using the Parental
Bonding Instrument, and CSA using a previously validated questionnaire. Current affective
symptoms were assessed from the depression scale of the GHQ-28.

Results. Low maternal and paternal care were associated with risk of abuse by a biologically
unrelated perpetrator before the age of 11, but not during early adolescence. Low maternal care and
CSA each made independent contributions to the prediction of affective symptoms. CSA by a non-
relative was strongly associated with GHQ depression, as was CSA by a non-relative that had
occurred only once.

Conclusions. Quality of parental care probably influences risk of CSA by unrelated abusers in
younger children, while there may be a combination of genetic and parental influences on the risk
of abuse by a relative. The strong association of affective symptoms in adult life with CSA by a non-
relative suggests an environmental effect. Studies, utilizing genetic designs, of the role of childhood
trauma in relation to adult affective symptoms are needed.
Swinburne on providence
Authors: GALE RICHARD M.
Published: July 2002

My review of Swinburne's elaborate and ingenious higher-good type
theodicy will begin with an examination of his argument for why the theist needs a
theodicy in the first place. After a preliminary sketch of his theodicy and its crucial
free-will plank, its rational-choice theoretic arguments will be critically scrutinized.

Richard Swinburne Providence and the Problem of Evil. (Oxford: Clarendon Press,
1998). Pp. xiii + 263. £35.50 Hbk. £14.99 Pbk.