bluuebunny/crossref_metadata_2025 huggingface dataset:
Evolution of Darwinian drift
Authors: YIH CHIA-SHUN
Published: July 2002

The evolution of drift with time at a plane normal to the passage

of a body from far

right to far left is investigated. It is shown that the measurable part

of the drift volume

as a function of time is uniquely determined, and that the indeterminacy

of Darwin's

drift integral simply does not matter to the physical world, in which

there is a Darwin

theorem stating that the drift mass is equal to the added mass. The method
for

determining the shape of the drift surface is also given.
From onset of unsteadiness to chaos in a differentially heated square
cavity
Authors: LE QUÉRÉ PATRICK , BEHNIA MASUD
Published: July 2002

We investigate with direct numerical simulations the onset of unsteadiness,
the route
to chaos and the dynamics of fully chaotic natural convection in an upright
square air-filled
differentially heated cavity with adiabatic top and bottom walls. The numerical

algorithm integrates the Boussinesq-type Navier–Stokes equations
in
velocity–pressure formulation with a Chebyshev spatial approximation
and a
finite-difference second-order
time-marching scheme. Simulations are performed for Rayleigh numbers up
to
1010, which is more than one order of magnitude higher
than the onset of unsteadiness.
The dynamics of the time-dependent solutions, their time-averaged structure
and
preliminary results concerning their statistics are presented. In particular,
the internal
gravity waves are shown to play an important role in the time-dependent
dynamics
of the solutions, both at the onset of unsteadiness and in the fully chaotic
regime.
The influence of unsteadiness on the local and global heat transfer coefficients
is also
examined.
Stability of vapour–liquid counter flow in porous media
Authors: PESTOV IRENE
Published: July 2002

A linear stability analysis of vapour–liquid counter
flow in porous media is carried out.
For the vapour-dominated basic state the development in time of both pressure
and
saturation disturbances is studied. The pressure field is shown to be asymptotically

stable for all choices of thermal boundary conditions, excluding the
insulating–insulating boundary condition for which it is neutrally
stable.
The saturation field is
proven to be Lyapunov stable: the saturation disturbance remains bounded
by an
infinitesimal number at all times. For both vapour- and liquid-dominated
basic states
the direction of propagation of small saturation disturbances is determined.
These
results explain the formation of two-layer geothermal structures and why
alternative
structures cannot develop within homogeneous reservoirs.
Natural convection far downstream of a heat source on a solid wall
Authors: HIGUERA F. J. , WEIDMAN P. D.
Published: July 2002

An analysis is presented of some steady natural convection flows
at large distances
downstream of point heat sources on solid walls. These asymptotic self-similar
flows
depend only on the Prandtl number of the fluid. The flow induced by a localized
source
on an adiabatic wall that is vertical or facing downwards is described
numerically,
whereas the flow due to a localized source on a wall facing upwards separates
and
leads to a self-similar plume. When the wall is held at the same temperature
as the
ambient fluid far from the source, the flow is described by a self-similar
solution of
the second kind, with the algebraic decay of the temperature excess above
the ambient
temperature determined by a nonlinear eigenvalue problem. Numerical solutions
of
this problem are presented for two-dimensional and localized heat sources
on a vertical
wall, whereas the problem for a localized heat source under an inclined
isothermal
downwards-facing wall turns out to capture the Rayleigh–Taylor instability
of the
flow and could not be solved by the methods used in this paper. The analogous

flows in fluid-saturated porous media are found to be the solutions of
parameter-free
problems. A conservation law similar to the one holding for a wall jet
is found in the
case of a two-dimensional source on an isothermal wall and numerical solutions
are
presented for the other cases.
Spin-up of stratified rotating flows at large
Schmidt number: experiment and theory
Authors: HEWITT R. E. , DAVIES P. A. , DUCK P. W. , FOSTER M. R.
Published: July 2002

We consider the nonlinear spin-up/down of a rotating stratified fluid in a conical
container. An analysis of axisymmetric similarity-type solutions to the relevant
boundary-layer problem, Duck, Foster & Hewitt (1997), has revealed three types of
behaviour for this geometry. In general, the boundary layer evolves to either a steady
state, or a gradually thickening boundary layer, or a finite-time singularity depending
on the Schmidt number, the ratio of initial to final rotation rates, and the relative
importance of rotation and stratification.

In this paper we emphasize the experimental aspects of an investigation into the
initial readjustment process. We make comparisons with the previously presented
boundary-layer theory, showing good quantitative agreement for positive changes
in the rotation rate of the container (relative to the initial rotation sense). The
boundary-layer analysis is shown to be less successful in predicting the flow evolution
for nonlinear decelerations of the container. We discuss the qualitative features of
the spin-down experiments, which, in general, are dominated by non-axisymmetric
effects. The experiments are conducted using salt-stratified solutions, which have a
Schmidt number of approximately 700.

The latter sections of the paper present some stability results for the steady
boundary-layer states. A high degree of non-uniqueness is possible for the system
of steady governing equations; however the experimental results are repeatable and
stability calculations suggest that ‘higher branch’
solutions are, in general, unstable.
The eigenvalue spectrum arising from the linear stability analysis is shown to have
both continuous and discrete components. Some analytical results concerning the
continuous spectrum are presented in an appendix.

A brief appendix completes the previous analysis of Duck, Foster & Hewitt (1997),
presenting numerical evidence of a different form of finite-time singularity available
for a more general boundary-layer problem.
Linear stability of thermocapillary convection
in cylindrical liquid bridges under
axial magnetic fields
Authors: PRANGE M. , WANSCHURA M. , KUHLMANN H. C. , RATH H. J.
Published: July 2002

The stability of axisymmetric steady thermocapillary convection of electrically
conducting fluids in half-zones under the influence of a static axial magnetic field is
investigated numerically by linear stability theory. In addition, the energy transfer
between the basic state and a disturbance is considered in order to elucidate the mechanics
of the most unstable mode. Axial magnetic fields cause a concentration of the
thermocapillary flow near the free surface of the liquid bridge. For the low Prandtl
number fluids considered, the most dangerous disturbance is a non-axisymmetric
steady mode. It is found that axial magnetic fields act to stabilize the basic state.
The stabilizing effect increases with the Prandtl number and decreases with the zone
height, the heat transfer rate at the free surface and buoyancy when the heating is
from below. The magnetic field also influences the azimuthal symmetry of the most
unstable mode.
Symmetries of and entropy production by transport in toroidal confinement systems
Authors: SUGAMA H. , HORTON W.
Published: July 2002

A synthesized formulation of classical, neoclassical and anomalous
transport in
toroidal confinement systems with electromagnetic fluctuations and large
mean
flows is presented. The positive-definite entropy production rate and the
conjugate
flux–force pairs are rigorously defined for each transport process.
The Onsager
symmetries of the classical and neoclassical transport matrices are derived
from the
self-adjointness of the linearized collision operator. The linear gyrokinetic
equation
with given electromagnetic fluctuations determines the anomalous fluxes
with the
quasilinear anomalous transport matrix, which satisfies the Onsager symmetry.
Interaction of a transverse electromagnetic wave with a bounded thermal
plasma
Authors: CHOI DUK-IN , YOON N. S.
Published: July 2002

Transmission, reflection and absorption of a transverse electromagnetic
wave by a
thermal plasma slab of finite width are investigated theoretically. By
solving the
Maxwell–Boltzmann equations using a mode-analysis method under appropriate

boundary conditions, the coefficients of transmission and reflection of
the
electromagnetic wave and the absorption rate by plasma electrons are obtained
as Fourier
series. We discuss the relevant physics of the results.
Two alternative approaches in the kinetic theory of a fully ionized
plasma
Authors: KLIMONTOVICH Yu. L.
Published: July 2002

A brief review of two alternative descriptions of non-equilibrium
processes in a fully
ionized plasma is presented. The example of ‘Landau damping’
is used to demonstrate
that some fundamental problems remain unsolved in the kinetic theory of

plasmas. These arise from inconsistent descriptions of the transition from
the
reversible equations of the mechanics of charged particles and fields to
the irreversible
equations for a continuous medium in the theory of plasmas. These difficulties
can
be overcome through consistently defining the structure of the continuous
medium
and the characteristics of dynamic instability of motion of particles.
This leads to
generalized irreversible kinetic equations that provide the basis for a
unified
description of non-equilibrium processes in a plasma on kinetic and hydrodynamic

scales.
Nonlinearly coupled Langmuir and dust-acoustic waves in a dusty plasma
Authors: SINGH S. V. , RAO N. N. , SHUKLA P. K.
Published: July 2002

The nonlinear propagation of coupled Langmuir and dust-acoustic
waves in a
multi-component dusty plasma is considered. The coupled mode propagation
is described
by a Schrödinger–Boussinesq system, which reduces to the
Schrödinger–KdV system
for unidirectional wave propagation. For stationary propagation, the coupled

waves are governed by a generic Hamiltonian that is integrable in both
sub- and the
supersonic regimes of Mach number. Depending on the parameter regimes,
exact
analytical solutions for the coupled waves having single-, double- and
triple-hump
structures for the Langmuir field intensity are obtained. The exact governing
equations
for large-amplitude waves are also derived, and are solved approximately.
The
existence conditions for large-amplitude localized solutions in the quasineutral
limit
are discussed.
Single-integral expressions for electron cyclotron damping,
relativistically and with an arbitrary
distribution function
Authors: SHKAROFSKY I. P.
Published: July 2002

The relativistic expressions for the dielectric-tensor elements
can be expressed
as a double integral over both parallel and perpendicular momenta. The
anti-Hermitian (damping) parts can be integrated over a delta function for either

one of these two momenta, leaving a single integral over the other momentum

variable. We review these expressions for either integration option, and

compare them with statements in the literature. We give the limits on the

remaining integral explicitly, for all positive or negative values of the
parallel
refractive index, whose magnitude can be less or greater than one. This
single-integral form can be applied to electron cyclotron harmonic damping for
any
distorted electron momentum distribution function. As an example, we recover

the results for a Maxwellian distribution. We also provide approximate
results
when the distribution function can be taken as a Maxwellian only in the

perpendicular-momentum direction. A computer program will be written for
a
distribution function subjected to distortion by both electron cyclotron
and
lower-hybrid waves.
Sabellaria, a polychaete host for the gastropods Noemiamea dolioliformis and Graphis albida
Authors: Killeen Ian J. , Light Janice M.
Published: July 2002

Molluscan biogeographical studies around the British Isles and along the north coast of France have revealed a recurring association between the tube-building polychaetes Sabellaria spp. and two marine snails: the pyramidellid gastropod Noemiamea dolioliformis and the aclid, Graphis albida. Whilst few pyramidellids are considered to be host-specific, the evidence from these studies has shown that living animals of N. dolioliformis are only ever associated with Sabellaria spp. There is also a clear relationship between G. albida and Sabellaria spp. but as yet insufficient evidence that it associates only with these polychaetes.
Larval Anisakis simplex B (Nematoda: Ascaridoidea) of short-finned squid (Cephalopoda: Ommastrephidae) in north-west Spain
Authors: Pascual S. , Gonzalez A.F. , Arias C. , Guerra A.
Published: July 2002

The role of the ommastrephid squids Illex coindetii and Todaropsis eblanae (Mollusca: Cephalopoda) collected from two areas in the north-eastern Atlantic waters (north-west Spain) as hosts for larval ascaridoid nematodes was examined from November 1992 to November 1993. The morphology, morphometric growth, population dynamics and electrophoretic identification of the anisakid nematodes was described. The correspondence of Anisakis type I larvae recovered from both squid species within the sibling species Anisakis simplex B is confirmed by comparative data on morphology, morphometry, and genetic evidences. Almost all somatic structures showed progressive and continuous allometric growth corresponding with increase in worm length. Seasonal changes in parasite population levels were evident in both sampling areas.
Diet of the European flying squid Todarodes sagittatus (Cephalopoda: ommastrephidae) in the Balearic Sea (western Mediterranean)
Authors: Quetglas A. , Alemany F. , Carbonell A. , Merella P. , Sánchez P.
Published: July 2002

Stomach contents of Todarodes sagittatus caught by trawlers working from 100 to 800 m depth in the Balearic Sea (western Mediterranean) were studied. From the 348 stomachs examined (153 males and 195 females) 33.62% were empty (39.21% in males and 29.74% in females). The diet of the squid was composed of 58 different prey items belonging to four major groups: Osteichthya, Crustacea, Cephalopoda and Chondrichthya. Osteichthyes, crustaceans and cephalopods were the most common prey, with a frequency of occurrence value of 84.85, 48.92 and 29.87% respectively. A change in the diet as the squid grows was observed, since juveniles feed basically on fishes while adults prey more actively on crustaceans. Analysis of the diet by size-classes reflected an ontogenetic migration to deeper waters since, parallel to the increase of size, a raise in the percentage of prey species inhabiting deeper waters was detected. Cannibalism was quite frequent, since T. sagittatus was the second most common cephalopod prey. Females had higher fullness-weight index and lower emptiness index than males, which reflects their major energetic demand for egg production.
Age and growth of two sympatric squid Loligo vulgaris and Loligo forbesi, in Galician waters (north-west Spain)
Authors: Rocha F. , Guerra A.
Published: July 2002

Age and growth of Loligo vulgaris and L. forbesi were studied by the examination of growth increments in 96 and 135 selected (white zone <10%) statoliths, respectively. Squid were obtained by monthly sampling from the catches of commercial trawling and hand-jigs in Galician waters (north-west Spain) between February 1991 and October 1993. Mantle length (ML) of L. vulgaris ranged from 70 to 480 mm and varied between 70 and 685 mm in L. forbesi. A negative allometry between statolith length and ML or body weight (BW) was found in both species. Sexual dimorphism was apparent in both species, males grew faster and longer than females. The statolith analysis suggests that growth patterns of L. vulgaris and L. forbesi in Galician waters are different. The exploited population of L. vulgaris was composed of two groups: one formed by individuals hatched in winter–spring and another by specimens hatched in summer–autumn. Squid hatched in winter–spring reached larger sizes at the same age than those hatched in summer–autumn. These two groups were also observed in L. forbesi. However, squid of this species hatched in winter–spring were smaller than those hatched in summer–autumn at the same age. Reasons for this discrepancy are discussed. The life span of L. vulgaris was about one year whereas the life span of L. forbesi extended to 18 months.
Fecundity of the deep-sea fish in the north-east atlantic Alepocephalus bairdii (Pisces: Alepocephalidae)
Authors: Allain V.
Published: July 2002

Alepocephalus bairdii is a deep sea fish caught but discarded by semi-industrial fisheries from the north-east Atlantic Ocean. Reproductive features were investigated on 448 females of 29–93 cm standard length (SL) captured over 2 y (December 1995–December 1997) at 800–1280 m off the west coast of the British Isles. The first maturity of females was determined at L50=55 cm SL. A well-defined spawning period could not be determined in this species; a batch spawner characterized by an indeterminate annual fecundity. Absolute batch fecundity was estimated between 458 and 7049 oocytes per female 63–88 cm SL.
Clonal and population variation in jellyfish symmetry
Authors: Gershwin Lisa-ann
Published: July 2002

While it is generally assumed that jellyfishes (Cnidaria: Scyphozoa) are stably tetramerous, variation in symmetry (i.e. unimerous to octamerous) can be observed in most populations at a rate of approximately 2%, but sometimes as high as 10%. This type of variation has been observed among clonemates during strobilation in five taxa, namely Aurelia aurita, A. labiata, Chrysaora fuscescens, Pelagia colorata, and Phacellophora camtschatica. It is currently unclear whether the symmetry variation is caused by genetic, environmental, or developmental factors, or some combination. Although hexamerous lineages were not bred successfully, lineages were raised with rates of variation higher than normal. Thus, there may be some genetic component to the variation. In one lineage observed over 4.5 months, the rate of non-tetramery declined substantially from an initial high of 88.9% to a final cumulative low of 29%. Apparently this lineage was able to stabilize tetramery over time, possibly indicating some self-correcting developmental mechanism. Furthermore, no difference was found in variation rates between stressed and unstressed polyps, indicating that environmental factors may not play an important role in symmetry determination in these animals. These results indicate stabilizing selection in controlling the expression of variable symmetry.
Heterospecific timing of waving display in ocypodid crabs Ilyoplax pusilla and Uca lactea
Authors: Aizawa Naohiro
Published: July 2002

This study explores whether timing adjustment in ocypodid waving also occurs between heterospecific pairs. Analysis of the dyadic interactions between neighbouring males of Ilyoplax pusilla and Uca lactea in the field showed that the former tended to wave with some delay after each U. lactea wave, while the latter was little influenced by I. pusilla waves. The heterospecific wave timing of I. pusilla by U. lactea waves can be viewed as a weakened form of the conspecific wave timing mechanism in this species.
The 1992 Calcutta Riot in Historical Continuum: A Relapse into ‘Communal Fury’?
Authors: Das Suranjan
Published: July 2002

Calcutta's failure to insulate itself from the communal hysteria that plagued the length and breadth of India in the aftermath of the demolition of Babri Masjid on 6 December 1992 came as a rude shock to the city's intelligentsia. True, the Great Calcutta Killing of August 1946 had initiated a vicious circle of communal rioting in the subcontinent climaxing in the ‘truncated settlement’ of 15 August 1947. The events of 1946–47 were viewed by left-wing intellectuals as a defeat of radicalism in post-Second World War Bengal politics. But the structural disarticulation between class and politics experienced during these Partition days was rapidly bridged in the western half of British Bengal that came to form a part of the Indian union. While other regions of India continued to be struck by periodic bouts of Hindu–Muslim violence, West Bengal remained relatively free of the communal virus. Calcutta, its capital city, emerged as the crucible of the country's left and democratic politics.
Masjid Manzilgah, 1939-40. Test Case for Hindu-Muslim Relations in Sind
Authors: KHUHRO HAMIDA
Published: July 2002

Masjid Manzilgah forms a chapter in a biography of Mohammed Ayub Khuhro on which the author is currently working. Khuhro (1901-80) was an important politician of Sind whose political career spanned over fifty years from 1921 to the end of the ‘seventies. He was a member of the Bombay Legislative Council from 1923 till the severance of the connection between Bombay and Sind in 1935 when the latter province attained autonomy under the Government of India Act of 1935. He was in the forefront of the political struggle for the ‘separation’ of Sind and after 1936 became a front-ranking Muslim League leader who helped organize the party in Sind and put it behind the Pakistan movement. Khuhro was the first Premier of Sind after independence and held that office altogether three times. He came into confrontation with Jinnah over the issue of severing Karachi from Sind and became identified as the protagonist of states' rights (or provincial autonomy) and as a champion of politicians' supremacy in the fight against the domination of the bureaucracy which bedevilled Pakistani politics for nearly half a century of its existence. This fight resulted in his repeated enforced exile from the political field depriving Pakistan of one of its most experienced public men during its formative years.
Ivermectin: effectiveness in lymphatic filariasis
Authors: BROWN K.R. , RICCI F.M. , OTTESEN E.A.
Published: July 2002

This detailed review of the published studies underlying ivermectin's recent registration for use in lymphatic filariasis (LF) demonstrates the drug's single-dose efficacy (over the range of 20–400μg/kg) in clearing microfilaraemia associated with both Wuchereria bancrofti and Brugia malayi infections of humans. While doses as low as 20μg/kg could effect transient microfilarial (mf) clearance, higher dosages induced greater and more sustained mf reduction. The single dose of 400μg/kg yielded maximal responses, but a number of practical considerations suggest that either 400μg/kg or 200μg/kg doses would be acceptable for use in LF control programmes. Associated safety assessments indicate that adverse events, which occur commonly following treatment of microfilaraemic individuals, develop not because of drug toxicity but because of host inflammatory responses to dying microfilariae killed by the ivermectin treatment. Ivermectin is, therefore, a highly effective and generally well tolerated microfilaricide that may soon become an essential component of many public health initiatives to interrupt transmission of lymphatic filarial infection in an effort to eliminate LF globally.
Effect of iron deficiency onTrichuris suisandAscaris suuminfections in pigs
Authors: PEDERSEN S. , SAEED I. , FRIIS H. , MICHAELSEN K. F.
Published: July 2002

The objective of this experiment was to detect a possible interaction between iron deficiency and intestinal nematode infections. We report on a 2×2 study where thirty-one 10-week-old pigs fed a low or a normal iron diet were infected with bothTrichuris suis(4500 eggs) andAscaris suum(1200 eggs). No significant difference was detected between diet groups with respect to parasitological parameters forA. suumor the total number of adultT. suisrecovered at necropsy 10 weeks p.i. However, in the low iron groupT. suiswere located more proximally and the worms were increased in length. A higher proportion of pigs with initial faecal egg excretion at 6 weeks p.i. was observed in the low iron group, indicating a shortened pre-patency period. Worm fecundity and total faecal egg excretion were also highest in the low iron group. A significant correlation was found between female worm length and fecundity. The peripheral eosinophil counts were diminished in the low iron host groups. The infected low iron group experienced more severe pathophysiological changes in terms of hypoalbuminaemia and decreases in erythrocyte volumes. A significant inverse correlation existed between iron content in the bone-marrow and liver (body) store. In conclusion, iron deficiency increased the severity ofT. suisinfection in pigs.
The effects of FaRPs on the motility of isolated muscle
strips from the liver fluke, Fasciola hepatica
Authors: GRAHAM M. K. , FAIRWEATHER I. , McGEOWN J. G.
Published: July 2002

The effects of a range of FMRFamide-related peptides (FaRPs) on
isometric
contractility were tested using isolated muscle
strips from the liver fluke, F. hepatica. The neuropeptides tested
were
the molluscan FaRPs, FMRFamide and
FLRFamide, the turbellarian FaRPs, RYIRFamide and GYIRFamide, the cestode
peptides, NPF and GNFFRFamide,
and the nematode FaRPs, AF-1 (KNEFIRFamide), AF-2 (KHEYLRFamide), AF-8
(KSAYMRFamide), and PF-4
(KPNFIRFamide). Dose-response experiments were undertaken at a concentration
range of 5 nM–5 μM for all of the
neuropeptides tested. FMRFamide and AF-8 caused statistically significant
increases in the amplitude and frequency of
contractions at concentrations of 0·5 μM and 5 μM.
FLRFamide and AF-2 also caused significant increases in contraction
frequency at concentrations of 0·5 μM and 5 μM,
although a significant increase in amplitude of contraction was observed
only at a concentration of 5 μM. GYIRFamide increased both
amplitude
and frequency significantly at concentrations of
50 nM, 0·5 μM and 5 μM. RYIRFamide
significantly increased frequency of contractions at concentrations of
0·5 μM and
5 μM, but failed to have a significant effect on contraction
amplitude. AF-1 at a concentration of 5 μM increased contraction
amplitude, but failed to have an effect on frequency at any of the concentrations
used. PF-4 caused a statistically significant
increase in both the amplitude and frequency of contractions at a concentration
of 5 μM. NPF and GNFFRFamide had
no effect on the in vitro motility of F. hepatica over
the
range of concentrations tested. The results are discussed in the
light of possible structure–activity relationships in the FaRPs tested.
Physiological effects of platyhelminth FMRFamide-related
peptides (FaRPs) on the motility of the monogenean
Diclidophora merlangi
Authors: MONEYPENNY C. G. , MAULE A. G. , SHAW C. , DAY T. A. , PAX R. A. , HALTON D. W.
Published: July 2002

The actions of known platyhelminth FaRPs on the contractility of
whole-worm preparations of the monogenean,
Diclidophora merlangi have been examined in vitro for
the
first time. All of the peptides tested had excitatory effects on
the motor activity of the worm. The order of potency for the peptides tested
was: YIRFamide > GYIRFamide =
RYIRFamide > GNFFRFamide = FLRFamide. However, although YIRFamide was
more potent than GYIRFamide,
the latter was the most efficacious on each of the motility parameters
(tension, contraction amplitude and contraction
frequency) examined at concentrations [ges ]0·1 μm.
Serotonin, which stimulates contractility in the worm was used as a
positive control. The excitatory activity of turbellarian and cestode
neuropeptides on a monogenean indicates at least some
structural similarities in the neuropeptide receptors of these classes
of flatworm.
Antigenic variability in Trichuris trichiura populations
Authors: CURRIE R. M. , NEEDHAM C. S. , DRAKE L. J. , COOPER E. S. , BUNDY D. A. P.
Published: July 2002

The present study examines antigenic variability for the human

whipworm Trichuris trichiura. Recognition by IgG of
somatic antigens of individual worms collected from 3 intensely infected

children from Jamaica, West Indies has been
investigated by immunoblotting. When probed with 1 plasma sample,
significant differences in recognition of 2 selected
antigens among worm populations and between male and female worms
was observed. In addition, there was evidence
for antigenic variability within worm populations at the individual
worm level. Such variation may have considerable
implications for the development of immunity to parasitic nematodes.
SPRM1lc, a heterodimeric amino acid permease light
chain of the human parasitic platyhelminth, Schistosoma
mansoni
Authors: SKELLY P. J. , PFEIFFER R. , VERREY F. , SHOEMAKER C. B.
Published: July 2002

The Schistosoma mansoni protein, SPRM1lc, is a light chain member of a new family of heterodimeric amino acid
permeases. These proteins require covalent association with a type II glycoprotein (like h4F2hc) for functional surface
localization when expressed in Xenopus oocytes. We previously reported that, when co-expressed with h4F2hc, the
transport properties of SPRM1lc resemble system y and y+ while its human homologue, E16, functions as an L-type
permease. Here we extend the functional characterization of SPRM1lc in oocytes and show by competitor studies that its
amino acid transport capacity is similar to that of whole adult schistosomes. We demonstrate by Northern and Western
analysis that SPRM1lc is expressed within both larval and adult schistosomes. In all stages, SPRM1lc is associated into
a high molecular weight complex that can be disrupted by reducing agents, consistent with the hypothesis that a significant
fraction of the endogenous SPRM1lc is linked by a disulphide bond to an uncharacterized schistosome amino acid
transporter heavy chain. Immunofluorescence localization detects SPRM1lc in miracidia, daughter sporocysts and adult
worms. Confocal microscopy demonstrates that SPRM1lc is found in the apical membrane of the syncytial, double-lipid
bilayer tegument which surrounds adult worms. Aqueous biotinylation studies on living worms show that SPRM1lc is
exposed on the host-interactive surface of this tegumental membrane. Host exposed, functionally important surface
proteins such as SPRM1lc could form the basis of an effective schistosomiasis vaccine. These studies are the first to
describe a helminth amino acid transporter, and the first to characterize an invertebrate heterodimeric amino acid
transporter.
Classical neurotransmitters in the ovijector of Ascaris suum: localization and modulation of muscle activity
Authors: FELLOWES R. A. , MAULE A. G. , MARTIN R. J. , GEARY T. G. , THOMPSON D. P. , KIMBER M. J. , MARKS N. J. , HALTON D. W.
Published: July 2002

Ascaris suum possesses a well-developed nervous system which is regulated by a number of classical neurotransmitters
including acetylcholine (ACh), γ-aminobutyric acid (GABA), glutamate and serotonin. The vagina vera, the distal part
of the ovijector, displays intrinsic, rhythmic activity which has been shown to be modulated by FMRFamide-related
peptides (FaRPs) in vitro. Confocal scanning laser microscopy coupled with immunocytochemistry, and histochemical
studies, revealed that the nerve plexus of the ovijector contains GABAergic and glutamatergic innervation. Although no
distinctive cholinergic or serotoninergic innervation was apparent, cholinesterase activity was localized to discrete areas
of the musculature of the vagina vera. The effects of classical transmitters on the activity of the vagina vera in vitro were
examined. ACh was excitatory, stimulating a brief but powerful contraction of the vagina vera with a threshold for activity
of 1 μM. Both GABA and glutamate were inhibitory, causing a cessation of contractile activity at high concentrations
(> 10 μM). Although less potent than glutamate, GABA had more profound effects and induced longer-lasting paralysis
of the tissue. The threshold concentrations for activity were 5 μM for glutamate and 10 μM for GABA. Serotonin had no
consistent effect on the vagina vera. This study demonstrates that classical transmitters modulate the activity of the
ovijector of A. suum.
Names, Verbs and Quantification Again
Authors: Denyer Nicholas
Published: July 2002

There are enormous differences between quantifying name-variables only, quantifying verb-variables only, and quantifying both. These differences are found only in the logic of polyadic predication; and this presumably is why Richard Gaskin thinks that they distinguish names from transitive verbs only, and not from verbs generally. But that thought is mistaken: these differences also distinguish names from intransitive verbs. They thus vindicate the common idea that on the difference between names and verbs we may base grandiose metaphysical distinctions, and undermine Gaskin's idea that both names and verbs may be said to designate objects.
Are there sex differences in the reliability of a lifetime history of major depression and its predictors?
Authors: KENDLER K. S. , GARDNER C. O. , PRESCOTT C. A.
Published: July 2002

Background. Although lifetime major depression (LTMD) is assessed with only moderate reliability in community samples, some predictors have emerged for ‘reliable’ LTMD. Given the large impact of sex on risk for LTMD, it is of interest to know if there are sex differences in the reliability of LTMD and its predictors.

Methods. A total of 5603 members of male–male and male–female twin pairs from a population-based registry were interviewed twice with a mean inter-interview interval of 19 months. LTMD was assessed on each occasion using DSM-III-R criteria. Univariate and multivariate logistic regression analyses were used, combining forward and back-prediction.

Results. The long-term test–retest reliability of LTMD was moderate (κ = +0·48) and did not differ significantly between males and females. In a multivariate model, the significant predictors of a stable diagnosis of LTMD, none of which differed across sex, were younger age at onset, older current age, history of treatment, increasing number of symptoms, level of impairment or level of distress, longer duration of episodes, higher current level of depression and the presence during the depressive episode of sad mood, weight loss, hypersomnia or fatigue. Using these variables, it was not possible to predict ‘stably diagnosed’ LTMD with both high sensitivity and high specificity.

Conclusion. In community samples, LTMD is diagnosed with moderate reliability. Although diagnostic stability can be predicted by variables related to severity, distress and treatment-seeking (probably acting to make depressive episodes more ‘memorable’), highly accurate prediction of stably diagnosed cases is not possible. Long-term recall is also significantly influenced by current symptoms. Neither the stability of LTMD nor its predictors differ in men and women.
Cultural influences on the prevalence of common mental disorder, general practitioners' assessments and help-seeking among Punjabi and English people visiting their general practitioner
Authors: BHUI K. , BHUGRA D. , GOLDBERG D. , DUNN G. , DESAI M.
Published: July 2002

Background. Culture influences symptom presentation and help-seeking and may influence the general practitioner's assessment.

Methods. We recruited Punjabi and English GP attenders to a two-phase survey in London (UK) using the Amritsar Depression Inventory and the General Health Questionnaire as screening instruments. The Clinical Interview Schedule was the criterion measure. General practitioners completed Likert assessments.

Results. The second phase was completed by 209 Punjabi and 180 English subjects. The prevalence of common mental disorders was not influenced by culture. Punjabi cases more often had ‘poor concentration and memory’ and ‘depressive ideas’ but were not more likely to have somatic symptoms. General practitioners were more likely to assess Punjabis with common mental disorder as having ‘physical and somatic’ symptoms or ‘sub-clinical disorders’. Punjabi cases with depressive ideas were less likely to be detected compared with English ones. In comparison to English men, English women were under-detected by Asian general practitioners. Help-seeking English subjects were more likely to be correctly identified as cases.

Conclusions. The prevalence of common mental disorders and somatic symptoms does not differ across cultures. Among English subjects, general practitioners were more likely to identify correctly pure psychiatric illness and mixed pathology; but Punjabi subjects with common mental disorders were more often assessed as having ‘sub-clinical disorders’ and ‘physical and somatic’ disorders. English women were less well detected than English men. English help-seeking cases were more likely to be detected.
The relationship between smooth pursuit
performance, motion perception and sustained visual
attention in patients with schizophrenia and normal controls
Authors: STUVE T. A. , FRIEDMAN L. , JESBERGER J. A. , GILMORE G. C. , STRAUSS M. E. , MELTZER H. Y.
Published: July 2002

Background. In this study, we tested the hypothesis that low smooth pursuit gain in
schizophrenia is related to an abnormality in motion perception.

Methods. The subjects were 19 schizophrenics treated with clozapine and 19 controls. In addition
to smooth pursuit and motion perception paradigms, sustained attention was also assessed
using a continuous performance task (CPT).

Results. In the patient group, there was a statistically significant negative correlation between
smooth pursuit gain and motion perception threshold (r =−0·60, P<0·01). This relationship
was not secondary to attention deficits as assessed by the CPT.

Conclusions. Our results are consistent with the notion that the smooth pursuit gain deficit is
related to a deficit in motion perception rather than in attention. Brain area V5 (also referred to
as ‘MT’ in macaque), located in the parieto-occipital region, is known to be critically important
both for motion perception and gain. Thus, our results point to an abnormality in this area in
schizophrenia.
Attributions about common bodily sensations: their associations

with hypochondriasis and anxiety
Authors: MacLEOD A. K. , HAYNES C. , SENSKY T.
Published: July 2002

Background. Causal attributions about bodily sensations may

determine help-seeking and influence

patients' demands for medical treatment. The present study aimed

to differentiate the causal

attributions associated with health-related and non-health-related

anxiety.

Methods. Anxious hypochondriacal, generally anxious, and

non-anxious general practice attenders

were compared on their propensity to give somatic, psychological or

normalizing attributions for

common bodily sensations, measured by number of each type of

attribution in a given time period

and the frequency of first response of each type.

Results. The groups differed in all three types of

attributions. Giving more psychological and fewer

normalizing attributions was related to general anxiety whereas

giving more somatic attributions

was related specifically to hypochondriasis.

Conclusions. Anxiety and hypochondriasis can be

distinguished in terms of their associated patterns

of attributions for bodily sensations, reinforcing the importance

of attributional processes and

interventions which use reattributional training.
General practitioners' attitudes to psychiatric and medical illness
Authors: LAWRIE S. M. , MARTIN K. , McNEILL G. , DRIFE J. , CHRYSTIE P. , REID A. , WU P. , NAMMARY S. , BALL J.
Published: July 2002

Background. General practitioners are increasingly involved
in the care of patients with long-term
psychiatric disorders. We have previously reported that general practitioners
are less willing to treat
patients with schizophrenia than those without such a diagnosis, but this
may have been attributable
to a reluctance to treat patients with any psychiatric or chronic illness.
We, therefore, examined
general practitioners' attitudes to patients with chronic psychiatric
or medical illnesses.

Methods. A random sample of 260 local general practitioners
were each sent one of our case
vignettes which were identical apart from mention of a previous diagnosis
of schizophrenia,
depression, diabetes or no illness. The general practitioners were asked
to indicate their level of
agreement with 13 attitudinal statements based on the vignette.

Results. One hundred and sixty-six (66%) of the general practitioners
responded to the case
vignettes. Those responding to the vignette about the patient with schizophrenia
were less happy to
have that patient on their practice list and were more concerned about
the risk of violence and the
child's welfare. Those responding to the depression vignette were
more likely to offer the patient
antidepressants or counselling; and those who replied to the diabetes case
were most likely to refer
the patient to a hospital specialist. These differences were not attributable
to the personal or practice
characteristics of the general practitioners.

Conclusions. Patients with schizophrenia arouse concerns in
general practitioners that are not
simply due to those patients suffering from a psychiatric or chronic illness.
Our results suggest that
some patients with schizophrenia may find it difficult to register with
a general practitioner and
receive the integrated community-based health care service they require.
Psychiatrists should
provide education and support to general practitioners who look after patients
with schizophrenia.
Sadness in older persons: 13-year follow-up of a
community sample in Baltimore, Maryland
Authors: GALLO J. J. , RABINS P. V. , ANTHONY J. C.
Published: July 2002

Background. Our prior psychometric work suggested that
older adults interviewed in 1981 in a
community survey were less likely than younger adults to report dysphoria.
We hypothesized that
this would also be true of older adults interviewed 13 years later.

Methods. This study is a population-based 13-year follow-up
survey of community-dwelling adults
living in East Baltimore in 1981. Subjects were the continuing participants
of the Baltimore
Epidemiologic Catchment Area Program. After excluding 269 adults who were
65 years of age and
older at initial interview in 1981, 1651 adults remained (347 aged 65 years
and older and 1304 who
were 30–64 years-old at follow-up).

We applied structural equations with a measurement model for dichotomous
data (the MIMIC
– multiple indicators, multiple causes – model) to compare
symptoms between adults who were 65
years and older at follow-up with younger adults, in relation to the nine
symptom groups
comprising the diagnostic criteria for major depression, adjusting for
several potentially influential
characteristics (namely, gender, self-reported ethnicity, educational attainment,
cognitive
impairment, marital status and employment).

Results. Older adults were less likely to endorse sadness as
evidenced by a direct effect coefficient
of −0·335 (95% Confidence Interval −0·643, −0·027).

After adjusting for several potentially
influential characteristics, the direct effect of age was substantially
unchanged
(−0·298 (95% CI −0·602, −0·006)).

Conclusions. Older adults in 1994, like older adults in 1981,
were less likely to endorse sadness than
younger persons. This finding suggests, but does not prove, that the observed
age difference in
reporting depression does not reflect a cohort effect.
The assessment of dependence in the study of stressful life events:
validation using a twin design
Authors: KENDLER K. S. , KARKOWSKI L. M. , PRESCOTT C. A.
Published: July 2002

Background. In the assessment of stressful life events (SLEs), researchers have often tried to evaluate
whether individual events are dependent or independent of the respondent's behaviour. We sought
to validate this evaluation using a twin methodology. We predicted that dependent SLEs would be
more heritable than independent SLEs.

Methods. We explored, by twin modelling, the resemblance in two pairs of past-year personal and
network SLEs rated individually, by trained interviewers, on a four-point dependence–independence
scale. We examined results from two waves of interviews with 785 female–female twin pairs
ascertained from a population based registry.

Results. Twin model-fitting found no evidence for genetic effects on personal or network
independent SLEs. However, familial–environmental factors played an important role in the
aetiology of network independent SLEs. For personal and network dependent SLEs, by contrast,
three of four analyses suggested a significant aetiological role for genetic factors with estimated
heritabilities ranging from 19 to 51%.

Conclusions. Our results support the validity of interviewer assessments of dependence versus
independence of SLEs. As predicted, these assessments were relatively successful at distinguishing
SLEs that were influenced by genetic factors from those that were not.
Effects of neuroleptic medications on speech disorganization in schizophrenia: biasing associative networks towards meaning
Authors: GOLDBERG T. E. , DODGE M. , ALOIA M. , EGAN M. F. , WEINBERGER D. R.
Published: July 2002

Background. While some cognitive accounts of disorganized speech, or thought disorder, in schizophrenia have emphasized failures in working memory/discourse planning or selective attention, we have suggested that thought disorder resides in the semantic system. In this study we assessed the effect of neuroleptic medication on thought disorder and semantic processing.

Methods. Seventeen patients with schizophrenia were assessed while receiving neuroleptic medications and in crossover fashion, placebo. A number of measures were obtained: clinically rated thought disorder (using the Thought, Language and Communication Scale); working memory (letter number span); lexical integrity (naming and receptive vocabulary); and, semantic priming of intracategorical word pairs.

Results. Semantic priming measures improved with neuroleptic medication, as did clinically rated thought disorder. No other measure changed significantly. Priming selectively covaried with changes in thought disorder.

Conclusion. Changes in spreading semantic activation, measured in a semantic priming paradigm and presumably brought about by neuroleptics' influence on dopaminergic neuromodulatory systems, might reflect changes in the biases of pre-existing associative networks that favour or increase the accessibility of representations related by shared features. This study also has implications for the architecture of normal language in that a dissociation between the lexical and semantic levels was observed, due to the selective compromise of tasks demanding semantic processing.
Are recent increases in deliberate self-harm associated with changes in socio-economic
conditions? An ecological analysis of patterns of deliberate self-harm in Bristol 1972–3 and 1995–6
Authors: GUNNELL D. , SHEPHERD M. , EVANS M.
Published: July 2002

Background. The incidence of deliberate self-harm (DSH) in Britain has increased markedly over the last 30 years. Reasons for this rise are not clear. We have investigated whether changes in the social and economic environment underlie any of the recent increase in DSH incidence.

Methods. An ecological analysis was used to assess associations between changes in census-based measures of the social and economic environment – the Townsend Deprivation Index and a three-factor social fragmentation index – and changes in age- and sex-specific hospital attendance rates for DSH for the 28 wards of the city of Bristol between 1972–3 and 1995–6.

Results. There were significant cross-sectional associations between the Townsend Index and rates of DSH in both males and females in both time periods. Increases in Townsend Index were also associated with increases in DSH. This association was statistically significant at the 5% level in 25–34 year-old females. Associations with the social fragmentation index were weak, although our index was based on rather limited data.

Conclusions. This analysis suggests that changes in levels of socio-economic deprivation may influence area-specific patterns of DSH and such changes may have contributed to recent rises in DSH.