bluuebunny/crossref_metadata_2025 huggingface dataset:
A note on constraints in turbulence modelling
Authors: SPALART PHILIPPE R. , SPEZIALE CHARLES G.
Published: July 2002

We show that the class of constitutive relations for turbulence models put forward by Wang (1997) in this journal conflicts with dimensional analysis, unless the turbulent
Reynolds stresses were to be tied to the molecular viscous stresses everywhere in the flow. We then reiterate, using counter-examples, that the controversial postulate of
material frame-indifference is unfounded for turbulence, and is counter-productive in
the quest for accuracy. We add a comment on the role of acceleration.
A comparative study of two-phase flow models
relevant to bubble column dynamics
Authors: MINEV P. D. , LANGE U. , NANDAKUMAR K.
Published: July 2002

Multiphase flow modelling is still a major challenge in fluid dynamics and, although
many different models have been derived, there is no clear evidence of their relevance
to certain flow situations. That is particularly valid for bubbly flows, because most
of the studies have considered the case of fluidized beds. In the present study
we give a general formulation to five existing models and study their relevance
to bubbly flows. The results of the linear analysis of those models clearly show
that only two of them are applicable to that case. They both show a very similar
qualitative linear stability behaviour. In the subsequent asymptotic analysis we derive
an equation hierarchy which describes the weakly nonlinear stability of the models.
Their qualitative behaviour up to first order with respect to the small parameter is
again identical. A permanent-wave solution of the first two equations of the hierarchy
is found. It is shown, however, that the permanent-wave (soliton) solution is very
unlikely to occur for the most common case of gas bubbles in water. The reason is
that the weakly nonlinear equations are unstable due to the low magnitude of the
bulk modulus of elasticity. Physically relevant stabilization can eventually be achieved
using some available experimental data. Finally, a necessary condition for existence
of a fully nonlinear soliton is derived.
Simulation of turbulent flow over idealized water waves
Authors: SULLIVAN PETER P. , McWILLIAMS JAMES C. , MOENG CHIN-HOH
Published: July 2002

Turbulent flow over idealized water waves with varying wave slope ak and wave age
c/u∗ is investigated using direct numerical simulations at a bulk Reynolds number
Re = 8000. In the present idealization, the shape of the water wave and the associated
orbital velocities are prescribed and do not evolve dynamically under the action of
the wind. The results show that the imposed waves significantly influence the mean
flow, vertical momentum fluxes, velocity variances, pressure, and form stress (drag).
Compared to a stationary wave, slow (fast) moving waves increase (decrease) the
form stress. At small c/u∗, waves act
similarly to increasing surface roughness zo
resulting in mean vertical velocity profiles with shorter buffer and longer logarithmic
regions. With increasing wave age, zo decreases so that the wavy lower surface is
nearly as smooth as a flat lower boundary. Vertical profiles of turbulence statistics
show that the wave effects depend on wave age and wave slope but are confined
to a region kz < 1 (where k is the wavenumber of
the surface undulation and z is
the vertical coordinate). The turbulent momentum flux can be altered by as much as
40% by the waves. A region of closed streamlines (or cat's-eye pattern) centred about
the critical layer height was found to be dynamically important at low to moderate
values of c/u∗. The wave-correlated
velocity and flux fields are strongly dependent
on the variation of the critical layer height and to a lesser extent the surface orbital
velocities. Above the critical layer zcr the positions of the maximum and minimum
wave-correlated vertical velocity ww occur upwind
and downwind of the peak in zcr,
like a stationary surface. The wave-correlated flux
uwww is positive (negative) above
(below) the critical layer height.
Noise generation by high-frequency gusts interacting with an airfoil in transonic flow
Authors: EVERS I. , PEAKE N.
Published: July 2002

The method of matched asymptotic expansions is used to describe the sound generated
by the interaction between a short-wavelength gust (reduced frequency k,
with k [Gt ] 1) and an airfoil with small but non-zero thickness,
camber and angle of attack (which are all assumed to be of typical size
O(δ), with δ [Lt ] 1) in transonic flow. The mean-flow Mach number is taken to differ from unity by O(δ2/3), so that the steady flow
past the airfoil is determined using the transonic small-disturbance equation. The
unsteady analysis is based on a linearization of the Euler equations about the mean
flow. High-frequency incident vortical and entropic disturbances are considered, and
analogous to the subsonic counterpart of this problem, asymptotic regions around the
airfoil highlight the mechanisms that produce sound. Notably, the inner region round
the leading edge is of size O(k−1), and
describes the interaction between the mean-flow
gradients and the incident gust and the resulting acoustic waves. We consider the
preferred limit in which kδ2/3 = O(1),
and calculate the first two terms in the phase
of the far-field radiation, while for the directivity we determine the first term (δ = 0),
together with all higher-order terms which are at most
O(δ2/3) smaller – in fact, this
involves no fewer than ten terms, due to the slowly-decaying form of the power series
expansion of the steady flow about the leading edge. Particular to transonic flow is
the locally subsonic or supersonic region that accounts for the transition between the
acoustic field downstream of a source and the possible acoustic field upstream of the
source. In the outer region the sound propagation has a geometric-acoustics form
and the primary influence of the mean-flow distortion appears in our preferred limit
as an O(1) phase term, which is particularly significant in view of the complicated
interference between leading- and trailing-edge fields. It is argued that weak mean-
flow shocks have an influence on the sound generation that is small relative to the
effects of the leading-edge singularity.
Social Categories, Ethnicity and the State in Yucatán, Mexico
Authors: GABBERT WOLFGANG
Published: July 2002

This article discusses the development of social categories and
ethnicity in the peninsula of Yucatán, Mexico, since the Conquest in the
sixteenth century. Based on the Yucatec case, it demonstrates that
ethnicity is not a ubiquitous form of social organisation, but rather a
historical process related to specific techniques of social distinction. It
argues that the starting point for the analysis of ethnicity should not be
ethnic collectives, but instead the ways in which individuals use ethnic
categories in social interaction.
Political Bargaining and Democratic
Transitions: A Comparison of
Nicaragua and El Salvador
Authors: O'SHAUGHNESSY LAURA NUZZI , DODSON MICHAEL
Published: July 2002

This article examines the relationship between pact-making and

democratic transitions in Nicaragua (1988–1997) and El Salvador (1990–1997).

We argue that the process of elite bargaining about regime change affects
the
prospects for the consolidation of democracy. We emphasise three factors:
(1) the
choices key actors make as they bargain about bargaining, (2) their willingness
to
‘under-utilise’ their power and (3) the influence of historical
and structural
contingencies upon the key choices made. Essential to our discussion of
historical
and structural contingencies is the interrelation of domestic and international

actors and the importance of demilitarisation and institutional reform.
We argue
that these three factors favoured El Salvador more than Nicaragua, although

neither nation has overcome the political polarisation characteristic of
transitional
regimes.
Chile's Neo-Liberal Revolution:
Incremental Decisions and Structural
Transformation, 1973–89
Authors: KURTZ MARCUS J.
Published: July 2002

This article analyses the surprising emergence of a comprehensive and
coherent neo-liberal developmental model during the period of military rule in
Chile. Rather than reflecting a clear and definitive choice, the political process
that produced this model was characterised by hesitation, policy contradiction,
shifting priorities, and incremental choices. This was a result of the military's
efforts to deal with two, often conflicting, overarching goals – economic and
political stabilisation – as they evolved and were redefined over time. The focus
on incremental, iterated decision-making weaves the insights of other explanations
based in underlying institutional, coalitional, or ideational factors into
a micro-political explanation that is consistent with the substantial variations in
policy outcome across different phases of military rule.
On certain violations of the Superiority

Condition, AgrO, and economy of derivation
Authors: BOšKOVIĆ ŽELJKO
Published: July 2002

This paper examines Superiority effects with VP internal constituents

in English,

Spanish and Bulgarian. It is argued in the paper that certain data concerning

Superiority effects provide evidence for the existence of AgrO. In particular,
they

provide evidence that Accusative wh-phrases undergoing syntactic

wh-movement

must move to SpecAgrOP on their way to SpecCP. The data examined in the
paper

are also shown to provide support for the Economy account of the Superiority

Condition.
The two faces of privatisation: political and economic logics in
transitional South Africa
Authors: Hentz James Jude
Published: July 2002

Privatisation has both an economic and a political face. In South Africa, this
Janus-faced character is revealed by the juxtaposition of economic and political
arguments for and against the process of privatisation initiated by the
National Party, during the transition to majority rule. This paper argues that
the NP set out to fundamentally reorganise the structure of South Africa's
political economy as an exit strategy. Although it justified privatisation by
employing economic arguments, this ostensible depoliticisation masked political
motives. Ironically, the weak economic case reveals the political face of
privatisation in South Africa. The timing and context of South Africa's
privatisation process is difficult to defend on economic grounds, but it did
make political sense.
Divisional morphogenesis in the marine ciliate Holosticha warreni (Ciliophora: Hypotrichida)
Authors: Hu Xiaozhong , Song Weibo , Warren Alan
Published: July 2002

The cortical development of the marine hypotrichous ciliate Holosticha warreni, found in coastal waters near Qingdao, China, was investigated using the protargol impregnation method. In the proter, disorganization of the parental adoral zone of membranelles and undulating membranes contributes to the formation of its oral primordia which replace the parental buccal apparatus completely. Cirral anlagen in both division parts derive from the breaking of primary primordia. Most midventral cirri join in the formation of these primordia which occurs de novo separately from the oral primordia. Each of the 11 to 13 oblique streaks divides into three segments (new cirri) while the last two anlagen produce four each. Two frontoterminal cirri derive from the posteriormost anlage. The marginal rows develop from the parental structure. The generation mode of dorsal kineties is of the ‘one group type’ without forming caudal cirri.
Temporal genetic heterogeneity within a developing mussel (Mytilus trossulus and M. edulis) assemblage
Authors: Pedersen E.M. , Hunt H.L. , Scheibling R.E.
Published: July 2002

The genetic structure of mussel recruits on a rocky shore in Nova Scotia was measured after a rare ice-scouring event which completely removed the intertidal community. Genotype frequencies were measured at three enzyme loci, phosphoglucose mutase (PGM), aminopeptidase-I (product of the leucine aminopeptidase (LAP) locus), and mannose phosphate isomerase (MPI), using cellulose acetate gel electrophoresis. The developing mussel assemblage was a mixture of Mytilus trossulus, M. edulis and their hybrids, with a greater proportion of the former species. Mussel settlers were collected for two years to examine whether genetic heterogeneity existed within and between cohorts of settlers. Settlement of mussels of both species began in April or May and continued into January. Temporal genetic heterogeneity was observed among groups of settlers, resulting from both variations in the relative proportions of the two species and from genetic heterogeneity within M. trossulus. Allele frequencies of mussel cohorts were followed from settlement to ten months post-settlement to investigate the possibility of species-specific selection and of genotype-specific selection within M. trossulus. Temporal genetic heterogeneity primarily was attributed to changes in the proportions of each species, indicating that post-settlement processes were species-specific. Early post-settlement changes were inconsistent, but later changes were clearly directional, resulting in decreased proportions of M. edulis in larger mussels in both years. There was some evidence of genotype-specific post-settlement mortality within M. trossulus, particularly during the early post-settlement period. Our results indicate that temporally variable settlement patterns and post-settlement selection interacted to produce temporal genetic heterogeneity in this mussel assemblage.
Mesozooplankton biomass in the Celtic Sea: a first approach to comparing and combining CPR and LHPR data
Authors: Batten S.D. , Hirst A.G. , Hunter J. , Lampitt R.S.
Published: July 2002

Zooplankton biomass varies on temporal, horizontal and vertical scales. However, data sets which incorporate all these dimensions at high resolution are very rare. Two devices which measure all these aspects have recently been simultaneously deployed in the Celtic Sea, the continuous plankton recorder (CPR) and the Longhurst–Hardy plankton recorder (LHPR). This demonstrates that integrated biomass derived from the LHPR are not significantly different from those derived using the CPR. Values have, therefore, been combined for the first time to describe the vertical distribution of mesozooplankton biomass at the Celtic Sea shelf edge through an annual cycle. This suggests that the surface biomass peak is broader at the shelf break than in the open ocean and in the autumn the main biomass peak may be below the depth sampled by the CPR.
Reproduction and dispersal at vents and cold seeps
Authors: Tyler P.A. , Young C.M.
Published: July 2002

Reproductive cycles are determined from samples taken at regular intervals over a period of time related to the assumed periodicity of the breeding cycle. Fiscal, ship time and sampling constraints have made this almost impossible at deep-sea vents and seeps, but there is an accumulating mass of data that cast light on these processes. It is becoming apparent that most reproductive processes are phylogenetically conservative, even in extreme vent and seep habitats. Reproductive patterns of species occurring at vents and seeps are not dissimilar to those of species from the same phyla found in non-chemosynthetic environments. The demographic structure of most vent and seep animals is undescribed and the maximum ages and growth rates are not known. We know little about how the gametogenic cycle is initiated, though there is a growing body of data on the size at first reproduction. Gametogenic biology has been described from seasonal samples for only one organism from vent/seep environments. For other species, the pattern of gametogenesis has been described from serendipitous samples that allow determination of reproductive effort, but such samples reveal little about energy partitioning during the gametogenic process. Some notable adaptations have been described in mature gametes, including modified sperm. Spawning has been observed for a number of species both in situ and in vitro. Knowledge of the larvae of vent/seep organisms has been derived from laboratory fertilizations, from field collections over vent and seep areas and, for molluscs, from protoconch or prodissoconch size and shape. Larval dispersal has been perhaps the most intractable aspect of reproduction. Because the length of larval life is known for only a single seep organism and no vent organism, we cannot infer dispersal distance from a knowledge of current velocities. Modelling has been used to assess the maximum larval distance that allows effective migration between vent sectors. An indirect approach has been to estimate gene flow within, and between, vent sites using DNA sequencing and electrophoretic techniques. Although data are still equivocal, there are indications of considerable mixing among populations within and between vent sectors of the same ridge. Our knowledge of reproductive biology in vent and seep organisms remains fragmentary, but with molecular and biochemical techniques, emerging larval culture techniques, and increased sampling effort, the pieces of the jigsaw will eventually form an overall picture.
Population dynamics of an inarticulate brachiopod Lingula unguis on the intertidal flats of Kunsan, Korea
Authors: Park K.Y. , Oh C.W. , Hong S.Y.
Published: July 2002

Investigations were made on spatial and temporal variation, population structure, growth, recruitment and mortality in the intertidal flats of Kunsan (Korea, Yellow Sea) of an inarticulate brachiopod Lingula unguis. Statistical analysis indicates significant spatial differences and a significant relationship between density and ratio of sands to silts, suggesting that the distribution and density of this species were related to particle size. The population consisted of three year-classes, with a similar size composition each year, of which the second year-class was a major component. From estimation of parameters of growth monthly length–frequency was analysed by ELEFAN. Parameters of growth were estimated, using the modified von Bertalanffy growth function (VBGF) model incorporating seasonal variation in growth. The growth parameters are: L∞=44.00 mm SL, K=0.88 y−1, C=0.90, WP=0.48. The recruitment pattern shows two major recruitments per year. The maximum life span is estimated as 3.45 y. Total mortality (Z) by length-converted catch curve was estimated at 3.65 y−1. The population mainly occurred in fine sands and exhibited patchy distribution.
Polydorid species (Polychaeta: Spionidae) in Japan, with descriptions of morphology, ecology and burrow structure. 2. Non-boring species
Authors: Sato-Okoshi Waka
Published: July 2002

A total of 11 polydorid species of the family Spionidae were extracted from non-calcareous substrata from Japan. The polydorids were: one Polydora sp., Polydora cornuta; three Dipolydora spp., Dipolydora quadrilobata, D. cardalia, D. socialis; one Carazziella sp., Carazziella spongilla; one Boccardiella sp., Boccardiella hamata; two Boccardia spp., Boccardia perata, B. proboscidea; three Pseudopolydora spp., Pseudopolydora cf. kempi, P. antennata, P. paucibranchiata. All inhabited mud deposits including mud in crevices of calcareous substrata, sponge and sandstone rocks, and were never found in self-excavated burrows in calcareous substrata. This study attempts to summarize and discuss the taxonomic, morphological, and behavioural characteristics of these non-boring species inhabiting Japanese waters and to compare them with the previously known boring species. The 11 non-boring species belonged to six genera. Thus their taxonomic and morphological variability was higher than those of boring species, which belonged only to three genera. A generic overview suggests that some genera contain many species capable of boring and others contain many species incapable of boring. Branchial blood vessels were thick and conspicuous in non-boring species. Moreover, they showed high crawling activity and a strong, vigorous palp movement. These observations suggest a possible link between boring activity and the morphology and behaviour in polydorids. In addition, Polydora cornuta, Dipolydora quadrilobata, D. cardalia, D. socialis, Boccardia perata and Pseudopolydora cf. kempi are new to Japan.
Framed, Blamed and Renamed: The Recasting of Islamic Jurisprudence in Colonial South Asia
Authors: KUGLE SCOTT ALAN
Published: July 2002

A system should be formed, which shall preserve as much as possible can be done, their institutions and laws to the
natives of Hindoostan, and attemper them with the mild spirit of British government.—John Bruce

Jurisprudence is the nexus where authoritative texts, cultural assumptions, and political expediency come together during a crisis. It is
therefore not so much a thing or a system as it is an experience, an interpretative experience. Yet the practice of
jurisprudence is very different from other types of interpretation because it is also an exertion of power. A legal
interpretation is a decision which mobilizes coercive forces to immediately solidify the interpretation into a social
reality. The administrative structure of courts and the legal rhetoric that flows through them disguise jurisprudence as
‘a system’ rather than revealing its nature as an interpretative experience; this disguise serves to heighten the authority
of these exercises of power and to limit the ability to contest them to specialists.
Courting Legitimacy or Delegitimizing Custom? Sexuality, Sambandham, and Marriage Reform in Late Nineteenth-Century Malabar
Authors: KODOTH PRAVEENA
Published: July 2002

At an interview which Della Vella [seventeenth century] had with the Zamorin, [the Samudiri or the ruler of Calicut]
there were present two little princesses of the Royal house aged 12 years each; and of them he says, ‘they were all
naked (as I said above the women generally go) saving that they had a very small blue cloth wrapped about their
immodesties. One of them being more forward could not contain, but approaching gently towards me, almost touched
the sleeve of my coat with her hand, made a sign of wonder to her sister, how could we go so wrapped up and
entangled in clothes. Such is the power of custom that their going naked seemed no more strange to us, than our being
clothed appeared extravagant to them.’

K. P. Padmanabha Menon
MARKAN CHRISTOLOGY: GOD-LANGUAGE FOR JESUS?
Authors: BORING M. EUGENE
Published: July 2002

It is possible to construct both ‘ontological’ and ‘chronological’ scales on which Mark's Christology is then plotted. In neither case, however, does the method correspond to Mark's own christological method, which uses narrative to juxtapose pictures of Jesus as both ‘truly human’ and ‘truly divine’. This essay explicates the ‘truly divine’ side of Mark's presentation, arguing that a number of Markan texts express a ‘high’ Christology without compromising either Jesus’ humanity or a truly monotheistic doctrine of God.
A NOTE ON MARKAN OPTICS
Authors: MARCUS JOEL
Published: July 2002

In one of the strangest stories in his strange Gospel, Mark records the two-stage healing of a blind man by Jesus in Bethsaida (8.22–6). Jesus’ first healing action of spitting on the man's eyes and laying hands on them is only partially successful; the man now sees something, but what he sees is people who look like walking trees (8.24). His vision is still unclear, so Jesus must repeat the therapy, this time with more felicitous results: και διεβλεψεν [sc. oτυϕγoς] και απεκατεστη και ενεβλεπεν τηλαυγως απαντα. But how exactly is this clause to be translated?
Gp63 gene polymorphism and population structure of Leishmania donovani complex: influence of the host selection pressure?
Authors: GUERBOUJ S. , VICTOIR K. , GUIZANI I. , SERIDI N. , NUWAYRI-SALTI N. , BELKAID M. , BEN ISMAIL R. , Le RAY D. , DUJARDIN J.C.
Published: July 2002

The gp63 encoding genes were characterized by PCR–RFLP in 35 isolates representative of the Leishmania donovani complex (L. infantum, L. donovani, L. archibaldi and L. chagasi), with special attention to Mediterranean L. infantum from different geographical origins, and in separate groups from Old World Leishmania (L. major, L. tropica and L. aethiopica). The aim was to evaluate how the possible selective pressure by the host on these important surface proteins would influence structuring of our sample. Comparison was carried out with the structure obtained (i) from reported isoenzyme data, characters supposed to vary neutrally, and (ii) from PCR–RFLP analysis of gp63 inter-genic regions, containing non-translated spacers and regulatory genes. Polymorphism within the gp63-encoding region, was much higher than in gp63 inter-genic regions. In the gp63 intra-genic dendrogram, the 4 species of L. donovani complex were discriminated and quite distinct from outgroups. Within L. infantum, geographical structuring was observed and did not overlap with the structure built-up from isoenzymes and inter-genic data. These results support the idea of a strong host-selection on gp63, at vector level but most of all at vertebrate (human or dog) immunological level. Furthermore, they illustrate how the nature of genetic characters may influence the perception of population structuring.
Mathematical models of parasite responses to host immune defences
Authors: ANTIA R. , LIPSITCH M.
Published: July 2002

We examine the evolution of microparasites in response to the
immune system of vertebrate hosts. We first describe a
simple model for an acute infection. This model suggests that the
within-host dynamics of the microparasite will be a
‘race’ between parasite multiplication and a clonally
expanding response by the host immune system, resulting either in
immune-mediated clearance or host death. In this very simple model,
in which there is only a single parasite and host
genotype, maximum transmission is obtained by parasites with intermediate

rates of growth (and virulence). We examine
how these predictions depend on key assumptions about the parasite and

the host, and consider how this model may be
expanded to incorporate the effect of additional complexities such as
host–parasite co-evolution, host polymorphism, and multiple infections.
Diagnosis of Oesophagostomum bifurcum and hookworm
infection in humans: day-to-day and within-specimen
variation of larval counts
Authors: PIT D. S. S. , DE GRAAF W. , SNOEK H. , DE VLAS S. J. , BAETA S. M. , POLDERMAN A. M.
Published: July 2002

Oesophagostomum bifurcum, as well as hookworm infections
are hyperendemic among humans in northern Togo and Ghana.
For parasite-specific diagnosis a coproculture is obligatory, because only
the infective larvae, and not the eggs, can be
distinguished morphologically. The sensitivity of duplicate coprocultures
from a single stool sample was found to be above
90% in comparison to a gold standard of 10 coprocultures made from a single
stool specimen. Prevalence of infection with
O. bifurcum and hookworm further increased with the number of
coprocultures made from each individual stool.
Notwithstanding the high sensitivity, intensity of infection per individual
varied considerably from day-to-day and the
number of larvae found in different samples out of 1 stool also varied
highly, both showing a heterogeneous distribution.
Surprisingly, daily fluctuation and within-specimen variation could not
be differentiated from each other, probably
because of the variation created by the coproculture technique. To estimate
the intensity of infection, it is sufficient to
make repeated coprocultures from only 1 individual stool sample. Laborious
collection of stool samples on subsequent
days does not give better estimates of the individual infection status.
Epidemiology and genetic variability of two species of
nematodes (Heligmosomoides polygyrus and Syphacia
stroma) of Apodemus spp.
Authors: MÜLLER-GRAF C. D. M. , DURAND P. , FELIU C. , HUGOT J.-P. , O'CALLAGHAN C. J. , RENAUD F. , SANTALLA F. , MORAND S.
Published: July 2002

The epidemiology and genetic variability of 2 parasitic nematodes
Heligmosomoides polygyrus and Syphacia stroma of
Apodemus spp. were investigated. Both are parasites of the same
host, exhibit a direct life-cycle and are dioecious. However,
H. polygyrus has a diploid and S. stroma a haplodiploid
mode of reproduction. Haplodiploidy may lead to a more female
biased sex ratio and reduced genetic variability. Levels of genetic diversity
were analysed using both isoenzyme
electrophoresis and RAPDs (random amplified polymorphic DNA). Both parasites
showed a female biased sex ratio with
a stronger bias for the haplodiploid parasite. Results showed significantly
fewer genetic polymorphisms as measured by
RAPDs for the haplodiploid parasite S. stroma in comparison with
H. polygyrus. Despite the observed female biased sex
ratio this could not be explained by a significant amount of inbreeding.
Heterozygote deficiency for individual allozyme
loci – which could indicate inbreeding – was not found in either
parasite species. Other features of the particular life-history of these species are likely to have an impact on the sex ratio
and genetic variability too.
Heterogeneity in the distribution of Strongyloides ratti
infective stages among the faecal pellets of rats
Authors: HARVEY S. C. , PATERSON S. , VINEY M. E.
Published: July 2002

The distribution of helminth parasites within their host population is usually overdispersed and can be described by the
negative binomial distribution. The causes of this overdispersion are poorly understood, but heterogeneity in the
distribution of infective stages within the environment has been implicated as a possible factor. Here we describe the
distribution of infective stages of the rat intestinal nematode parasite Strongyloides ratti among the faecal pellets of its host.
The distribution of infective stages between faecal pellets is overdispersed and well described by the negative binomial
distribution. This overdispersion increases during the course of infection and occurs over a range of infection intensities.
Overdispersion of nematode infective stages among faecal pellets may result in increased spatial heterogeneity of the
infective stages in the environment and thus may contribute to the generation of overdispersion of adult parasitic stages.
In addition, these findings raise important issues regarding the accurate quantification of helminth egg counts from faecal
samples.
Absence of lipophosphoglycan-like glycoconjugates in
Entamoeba dispar
Authors: BHATTACHARYA A. , ARYA R. , CLARK C. G. , ACKERS J. P.
Published: July 2002

Invasive amoebiasis is the result of infection of Entamoeba histolytica. The closely related Entamoeba dispar can colonize
the human gut but does not cause invasive disease. In this study, E. dispar was analysed for the presence of the
lipophosphoglycan-like (LPG) glycoconjugate known to be present on the cell surface of E. histolytica. E. dispar cells were
radio-isotope labelled with [3H]galactose or [3H]inositol. The acidic glycoconjugates were extracted and analysed by
hydrophobic chromatography over phenyl–Sepharose and by sodium dodecyl sulphate polyacrylamide gel electrophoresis.
No LPG-like molecules could be identified in E. dispar in contrast to E. histolytica, suggesting that these molecules may
be absent in the non-pathogenic species.
The nervous system of Amphilina foliacea (Platyhelminthes, Amphilinidea). An
immunocytochemical, ultrastructural and spectrofluorometrical study
Authors: BISEROVA N. M. , DUDICHEVA V. A. , TERENINA N. B. , REUTER M. , HALTON D. W. , MAULE A. G. , GUSTAFSSON M. K. S.
Published: July 2002

The nervous system of young and adult Amphilina foliacea was studied with immunocytochemical, electron microscopical
and spectrofluorometrical methods. The general neuroanatomy is described in detail. New data on the structure and
development of the brain were obtained. The 5-HT and GYIRFamide-immunoreactivities occur in separate sets of
neurones. The innervation of the reproductive organs is described. The fine structure of 2 types of neurones in the CNS,
a sensory neurone, a ‘glial’ cell type, the neuropile and the synapses are described. The level of 5-HT varies between 0·074
and 0·461 μg/g wet weight. This is the first detailed study of the nervous system of A. foliacea. Earlier data on the structure
of the nervous system in A. foliacea published in Russian are introduced into the discussion. The study provides data that
can be used when considering the phylogenetic position of Amphilinidea.
The Problem of Induction
Authors: CARGILE JAMES
Published: July 2002

No one doubts that philosophers have discussed at length ‘the problem of induction’, but it would also be generally recognized that there would be disagreement as to precisely what that problem is. Rather than tackle the formulation problem, I will borrow from a popular text:

Our existence as well as science itself is based on the principle of induction that tells us to reason from past frequencies to future likelihoods, from the limited known of the past and present to the unknown of the past, present, and future ... But though inductive probability is psychologically inescapable, we have trouble providing a rational justification for it.

We might say, then, that there is such a practice as induction, and a problem associated with it is that of justifying engaging in it. We engage in reasoning from things we know about the past and present to conclusions about the past, present and future. We can't resist doing this but we have trouble finding a rational justification for doing so. This problem suggests a generalization. We engage in reasoning, reaching new conclusions. It would be hard to resist engaging in this practice. How do we provide a rational justification for it?
Decreasing seasonal variation of births in schizophrenia
Authors: SUVISAARI J. M. , HAUKKA J. K. , TANSKANEN A. J. , LÖNNQVIST J. K.
Published: July 2002

Background. Patients with schizophrenia have a winter–spring excess of births compared with the
general population, the cause of which is unresolved. Fluctuations in the magnitude of the seasonal
variation may provide clues to its aetiology.

Methods. All Finnish patients with schizophrenia born between 1950 and 1969 (N = 15892) were
identified from two nationwide health-care registers. Their background demographic information
was obtained from the Population Register Centre, which also provided monthly numbers of births
in each municipality of Finland as multidimensional tables, with sex and year, month and place of
birth as marginals. The incidence of schizophrenia was modelled using Poisson regression analysis,
with sex, onset age, birth cohort, place of birth (urban/rural), trend and seasonal variation as
explanatory variables. We also constructed a monthly time series and decomposed it into three
components – seasonal, trend and remainder.

Results. Seasonal variation of births among patients born in the 1950s, especially between 1955 and
1959, was marked, but decreased among patients born in the 1960s. No interaction between place
of birth or sex and seasonal variation was observed. The incidence was higher among the rural-born
than the urban-born, but declined more slowly among the urban-born than the rural-born.

Conclusions. The intensity of the factor causing the seasonal variation of births in schizophrenia
may be decreasing. Urban birth may be emerging as a risk factor for schizophrenia in Finland, as
elsewhere.
Genetic and environmental influences on anorexia nervosa syndromes in a population–based twin sample
Authors: KLUMP K. L. , MILLER K. B. , KEEL P. K. , McGUE M. , IACONO W. G.
Published: July 2002

Background. Genetic and environmental influences on broadly-defined anorexia nervosa (AN) syndrome were examined in a population-based twin sample.

Methods. AN syndrome was assessed in 672 female 17 year-old twins using structured interviews and a self-report questionnaire.

Results. Twenty-six probands with AN syndrome were identified. Biometrical model-fitting analyses indicated that genetic and non-shared environmental factors accounted for 74 % and 26 % of the variance in AN syndrome, respectively.

Conclusions. Findings support previous research indicating significant genetic and non-shared environmental influences on AN syndromes.
Parents concordant for major depressive disorder and the effect of psychopathology in offspring
Authors: NOMURA Y. , WARNER V. , WICKRAMARATNE P.
Published: July 2002

Background. Concordance for major depressive disorder (MDD) between parents could happen for different reasons. Regardless of the origin and the frequency of the concordance, the effect on offspring of having two parents affected with MDD may be serious. The sex of the affected parent and offspring may also be a important risk factor for MDD in offspring.

Methods. We examined the increased risk of psychopathology among offspring of the four parental mating groups: both parents affected with MDD (N = 53); only mother affected (N = 31); only father affected (N = 65); and, neither parents affected (N = 33). Parents and offspring were assessed by direct interview, conducted blind and independently of each other.

Results. Among the four parental mating groups, offspring of both parents affected had the highest risk of MDD, anxiety disorder and alcohol dependence, and the earliest age of onset for MDD. There were two exceptions: the highest risk of conduct disorder and of drug dependence was in the groups where only the father was affected and where only the mother was affected, respectively. Mother's MDD was a stronger predictor of MDD in male compared to female offspring. Father's MDD was a stronger predictor of MDD in female compared to male offspring.

Conclusion. Having two parents with MDD increases the risk of psychiatric disorders in offspring. A clear dose–response relationship between the number of affected parents and psychiatric disorders in offspring was observed. The sex of the affected parent and of the offspring is important in determining the risk to offspring. For an examination of the risk to psychopathology in offspring, diagnosis status of both parents should be considered.
The Brief Social Phobia Scale: a psychometric evaluation
Authors: DAVIDSON J. R. T. , MINER C. M. , DE VEAUGH-GEISS J. , TUPLER L. A. , COLKET J. T. , POTTS N. L. S.
Published: July 2002

The Brief Social Phobia Scale (BSPS) is an observer-rated scale designed to assess the
characteristic symptoms of social phobia, using three subscales – fear, avoidance, and physiological
arousal – which may be combined into a total score. Each of 18 BSPS items is anchored to a 5-point
rating scale. Psychometric evaluation of the BSPS in a sample of 275 social-phobia patients yielded
a high level of reliability and validity. Test–retest reliability was excellent, as was internal
consistency. The fear and avoidance subscales demonstrated highly significant correlations with
remaining item totals; however, the physiological subscale did not. The BSPS also demonstrated
significant relationships with other established scales that assess anxiety and disability, and it proved
sensitive to treatment effects in a trial of a 5-HT3 antagonist and placebo. Factor analysis yielded
six meaningful factors. We conclude that the BSPS provides a reliable, valid, and sensitive measure
for the evaluation of social phobia.
Prevalence and predictors of depressive, anxiety and substance
use disorders in HIV-infected and uninfected men: a longitudinal
evaluation
Authors: DEW M. A. , BECKER J. T. , SANCHEZ J. , CALDARARO R. , LOPEZ O. L. , WESS J. , DORST S. K. , BANKS G.
Published: July 2002

Background. There is little agreement on whether the
prevalence of psychiatric disorder is elevated in HIV-seropositive
(HIV +) populations compared with uninfected persons. However,
evaluation of this issue has been limited by difficulties of sampling,
study design and failure to control for other risk factors for
disorder.

Methods. Prevalence and clinical characteristics of
DSM-III-R major depressive disorder (MDD), generalized anxiety
disorder, adjustment disorder, and alcohol and substance
abuse/dependence were evaluated in a representative sample of HIV +
men attending primary care physicians' offices in a defined
geographical area. Lifetime prevalence at baseline and 1-year rates
during longitudinal follow-up were determined for the 113 HIV + men, as
well as 57 HIV – men, via standardized interview. Multivariate
analyses considered unique and combined effects of HIV serostatus and
other risk factors on likelihood of disorder.

Results. Although there were no differences in lifetime
rates prior to baseline, HIV + men were at greater risk for disorders
during the prospective study period. For MDD, this effect was
maintained even after controlling for other risk factors. Several of
these other factors bore their own effects: regardless of HIV
serostatus, men were susceptible to psychopathology if at baseline
they were younger, had a lifetime psychiatric history, or had poor
social supports or a low sense of personal mastery.

Conclusions. The risk of certain psychiatric disorders
appears uniquely elevated in HIV + men. Since other factors also
influence risk, interventions designed to minimize psychopathology
during HIV infection should attend to both HIV-related and
non-HIV-related risk factors.
Recall of obstetric events by mothers of schizophrenic patients
Authors: CANTOR-GRAAE E. , CARDENAL S. , ISMAIL B. , McNEIL T. F.
Published: July 2002

Background. The aim of the current study was to evaluate

the utility of maternal recall for obtaining
history of obstetric complications (OCs) in psychiatric research.

Methods. Obstetric information from in-depth structured
maternal interviews and from hospital
birth records was compared in 45 mothers of schizophrenic patients and
34 control mothers. Both
types of information were blindly and independently scored for OCs
using the McNeil-Sjöström OC Scale.

Results. Considerable discrepancies were observed
between interviews and records, irrespective of
maternal group. No significant differences were found between
patient and control mothers in error
type (omission, commission, total retrospective error) or recall
facility for selected events. More
errors of commission were made by mothers of patients with negative family
history than mothers
of patients with positive family history for psychiatric disorder.
Patients had significantly more OCs
than controls only when hospital record information was utilized.

Conclusions. OC history obtained by maternal recall has methodological
limitations.
A four year prospective study of age-related
cognitive change in adults with Down's syndrome
Authors: OLIVER C. , CRAYTON L. , HOLLAND A. , HALL S. , BRADBURY J.
Published: July 2002

Background. While neuropathological studies indicate a
high risk for Alzheimer's disease in adults
with Down's syndrome, neuropsychological studies suggest a lower prevalence
of dementia. In this
study, cognitive deterioration in adults with Down's syndrome was
examined prospectively over
4 years to establish rates and profiles of cognitive deterioration.

Methods. Fifty-seven people with Down's syndrome aged
30 years or older were assessed using a
battery of neuropsychological tests on five occasions across 50 months.
Assessments of domains of
cognitive function known to change with the onset of Alzheimer related
dementia were employed.
These included tests of learning, memory, orientation, agnosia, apraxia
and aphasia. The individual
growth trajectory methodology was used to analyse change over time.

Results. Severe cognitive deterioration, such as acquired,
apraxia and agnosia, was evident in 28·3%
of those aged over 30 and a higher prevalence of these impairments was
associated with older age.
The rate of cognitive deterioration also increased with age and degree
of pre-existing cognitive
impairment. Additionally, deterioration in memory, learning and orientation
preceded the
acquisition of aphasia, agnosia and apraxia.

Conclusions. The prevalence of cognitive impairments consistent
with the presence of Alzheimer's
disease is lower than that suggested by neuropathological studies. The
pattern of the acquisition of
cognitive impairments in adults with Down's syndrome is similar to
that seen in individuals with
Alzheimer's disease who do not have Down's syndrome.
Gender differences in the effects of bereavement-related
psychological distress in health outcomes
Authors: CHEN J. H. , BIERHALS A. J. , PRIGERSON H. G. , KASL S. V. , MAZURE C. M. , JACOBS S.
Published: July 2002

Background. This study examined whether traumatic grief,
depressive and anxiety symptoms
formed three distinct factors for widows and widowers. In addition, we
examined whether high
symptom levels of traumatic grief, depression and anxiety predicted different
mental and physical
health outcomes for widows and widowers.

Method. Ninety-two future widows and 58 future widowers were
interviewed at the time of their
spouse's hospital admission and then at 6 weeks, 6, 13 and 25 month
follow-ups. Principal axis
factor analyses tested the distinctiveness of traumatic grief, depressive
and anxiety symptoms, by
gender. Repeated measures ANOVA tested for gender differences and changes
over time in mean
symptom levels of traumatic grief, depression and anxiety. Linear and logistic
regression models
estimated the effects of high symptom levels of traumatic grief, depression
and anxiety at 6 months
on health outcomes at 13 and 25 months post-intake by gender.

Results. Three distinct symptom clusters (i.e. traumatic grief,
depressive and anxiety symptoms)
were found to emerge for both widows and widowers. Widows had higher mean
levels of traumatic
grief, depressive and anxiety symptoms. High symptom levels of traumatic
grief measured at 6
months predicted a physical health event (e.g. cancer, heart attack) at
25 months post-intake for
widows. High symptom levels of anxiety measured at 6 months predicted suicidal
ideation at 25
months for widowers.

Conclusions. The results suggest that there are gender differences
in the levels of psychological
symptoms resulting from bereavement and in their effects on subsequent
mental and physical health
for widows and widowers.
Hippocampal/amygdala volumes in geriatric depression
Authors: ASHTARI M. , GREENWALD B. S. , KRAMER-GINSBERG E. , HU J. , WU H. , PATEL M. , AUPPERLE P. , POLLACK S.
Published: July 2002

Background. The hippocampus, amygdala and related functional circuits have been implicated in
the regulation of emotional expression and memory processes, which are affected in major
depression. Several recent investigations have reported abnormalities in these structures in adult
and elderly depressives.

Methods. Elderly DSM-III-R unipolar depressives (N=40) and normal controls (N=46)
participated in a magnetic resonance imaging study (1.0T). Brain images were obtained in the
coronal plane. Using established anatomical guidelines for structure delineation, volumetric
measurements of left and right hippocampus and anterior hippocampus/amygdala complex were
completed under blinded conditions using a semi-automated computer mensuration system, with
patients and controls in random order.

Results. Medial temporal volumes did not significantly distinguish either elderly depressed and age-similar normal control subjects, or late onset and early onset depressed patients (ANCOVA). Major
overlap of measured volumes existed between patient and control groups. In depressives,
hippocampal volumes significantly correlated with age, and cognitive and depression ratings, but
not with number of prior depressive episodes or age-at-onset of first depression.

Conclusions. Hippocampal volumes do not discriminate a typical clinical population of elderly
depressed patients from age-similar normal control subjects. If hippocampal dysfunction contributes
to a diagnosis of syndromal depression in the elderly, such dysfunction does not appear to be
regularly reflected in structural abnormalities captured by volumetric measurement as conducted.
On the other hand, relationships between hippocampal volumes and clinical phenomena in
depressives, but not controls, suggest potentially meaningful interactions between hippocampal
structure and the expression of major depression in the elderly.