bluuebunny/crossref_metadata_2025 huggingface dataset:
Vergerio's Anti-Nicodemite Propaganda and England, 1547–1558
Authors: OVERELL M. A.
Published: July 2002

Deceit is normally held in low esteem; pointing as it does to an evil
disposition; there are, nonetheless, countless instances when it has
reaped obvious benefits and deflected all manner of harm and ill report
and mortal perils. For our conversation is not always with friends in this
earthly life: Ariosto, Orlando Furioso, canto 4, i

A common response to the enforcement of religious conformity in
the sixteenth century was deceit, either by silence or dissimulation.
Contemporaries called people who chose this evasion Nicodemites,
after Nicodemus who came to Christ by night. The propaganda campaign
conducted against them by anti-Nicodemites stressed the necessity of
individual witness, supported by scriptural references. Virtually all the
major reformers made their contribution – Calvin, Viret, Bullinger –
even Bucer after an earlier more easy-going phase. Prominent among the
lesser lights were Italian exiles who had personal experience of Nicodemite
dilemmas after conformity began to be enforced in Italy in the early
1540s. Peter Martyr Vermigli, Francesco Negri and Caelio Secondo
Curione all wrote on the subject, but Pier Paolo Vergerio, who left his
Italian bishopric for exile in 1549, was by far the most outspoken and
prolific.
Surface forced internal waves and vortices in uniformly stratified and rotating fluids
Authors: KLOOSTERZIEL RUDOLF C.
Published: July 2002

The motion of an initially quiescent, incompressible, stratified and/or rotating
uid of semi-infinite extent due to surface forcing is considered. The stratification
parameter N and the Coriolis parameter f are constant but arbitrary and all possible
combinations are considered, including N = 0 (rotating homogeneous fluid), f = 0
(non-rotating stratified fluid) and the special case N = f. The forcing is suction or
pumping at an upper rigid surface and the response consists of geostrophic flows and
inertial-internal waves. The response to impulsive point forcings (Green's functions)
is contrasted with the response to finite-sized circularly symmetric impulsive forcings.
Early-time and large-time behaviour are studied in detail. At early times transient
internal waves change the vortices that are created by pumping/suction at the surface.
The asymptotically remaining vortices are determined, a simple expression for what
fraction of the initial energy is converted into internal waves is derived, as well as
wave energy fluxes and the dependence of the flux direction on the value of N/f.
The internal wave field is to leading order in time a distinct pulse, and rules for the
arrival time of the pulse, its amplitude, its motion along a ray of constant frequency
and decay with time, are given for the far field. A simple formula for the total wave
energy distribution as a function of frequency is derived for when all waves have
propagated away from the forcing.
Large-eddy simulation of a three-dimensional shear-driven turbulent boundary layer
Authors: KANNEPALLI CHANDRASEKHAR , PIOMELLI UGO
Published: July 2002

A three-dimensional shear-driven turbulent boundary layer over a flat plate generated
by moving a section of the wall in the transverse direction is studied using large-eddy simulations. The configuration is analogous to shear-driven boundary layer
experiments on spinning cylinders, except for the absence of curvature effects. The
data presented include the time-averaged mean flow, the Reynolds stresses and their
budgets, and instantaneous flow visualizations. The near-wall behaviour of the flow,
which was not accessible to previous experimental studies, is investigated in detail. The
transverse mean velocity profile develops like a Stokes layer, only weakly coupled to
the streamwise flow, and is self-similar when scaled with the transverse wall velocity,
Ws. The axial skin friction and the turbulent kinetic energy, K, are significantly
reduced after the imposition of the transverse shear, due to the disruption of the
streaky structures and of the outer-layer vortical structures. The turbulent kinetic
energy budget reveals that the decrease in production is responsible for the reduction
of K. The flow then adjusts to the perturbation, reaching a quasi-equilibrium three-dimensional collateral state. Following the cessation of the transverse motion, similar
phenomena take place again. The flow eventually relaxes back to a two-dimensional
equilibrium boundary layer.
Cusp formation for time-evolving bubbles in two-dimensional Stokes flow
Authors: SIEGEL MICHAEL
Published: July 2002

Analytical and numerical methods are applied to investigate the transient evolution
of an inviscid bubble in two-dimensional Stokes flow. The evolution is driven by
extensional incident flow with a rotational component, such as occurs for flow in a
four-roller mill. Of particular interest is the possible spontaneous occurrence of a cusp
singularity on the bubble surface. The role of constant as well as variable surface
tension, induced by the presence of surfactant, is considered. A general theory of time-
dependent evolution, which includes the existence of a broad class of exact solutions,
is presented. For constant surface tension, a conjecture concerning the existence of
a critical capillary number above which all symmetric steady bubble solutions are
linearly unstable is found to be false. Steady bubbles for large capillary number Q
are found to be susceptible to finite-amplitude instability, with the dynamics often
leading to cusp or topological singularities. The evolution of an initially circular
bubble at zero surface tension is found to culminate in unsteady cusp formation. In
contrast to the clean flow problem, for variable surface tension there exists an upper
bound Qc for which steady bubble solutions exist. Theoretical considerations as well
as numerical calculations for Q > Qc verify that the bubble achieves an unsteady
cusped formation in finite time. The role of a nonlinear equation of state and the
influence of surface diffusion of surfactant are both considered. A possible connection
between the observed behaviour and the phenomenon of tip streaming is discussed.
Nonlinear instability of a contact line driven by gravity
Authors: KALLIADASIS SERAFIM
Published: July 2002

A thin liquid mass of fixed volume spreading under the action of gravity on an
inclined plane develops a fingering instability at the front. In this study we consider the
motion of a viscous sheet down a pre-wetted plane with a large inclination angle. We
demonstrate that the instability is a phase instability associated with the translational
invariance of the system in the direction of flow and we analyse the weakly nonlinear
regime of the instability by utilizing methods from dynamical systems theory. It is
shown that the evolution of the fingers is governed by a Kuramoto–Sivashinsky-type
partial differential equation with solution a saw-tooth pattern when the inclined plane
is pre-wetted with a thin film, while the presence of a thick film suppresses fingering.
Three-dimensional free convection in molten gallium
Authors: JUEL A. , MULLIN T. , BEN HADID H. , HENRY D.
Published: July 2002

Convective flow of molten gallium is studied in a small-aspect-ratio rectangular,
differentially heated enclosure. The three-dimensional nature of the steady flow is
clearly demonstrated by quantitative comparison between experimental temperature
measurements, which give an indication of the strength of the convective flow, and the
results of numerical simulations. The three-dimensional flow structure is characterized
by cross-flows which are an order of magnitude smaller than the main circulation, and
spread from the endwall regions to the entire enclosure when the Grashof number
is increased beyond Gr = 104. The mergence of these effects in the centre of the
enclosure leads to a complex central divergent flow structure which underpins the
observed transition to oscillatory convection.
The evolution of initially turbulent bluff-body
wakes at high internal Froude number
Authors: SPEDDING G. R.
Published: July 2002

Coherent vortex structures are formed in the late wakes of towed spheres
for all values of the internal Froude number,
F≡2U/ND∈ [10, 240]
(U is the body speed, D its
diameter, and N is the buoyancy frequency). The eventual emergence of
the long-lived
and stable pattern of alternating-signed patches of vertical vorticity is
characteristic
of all towed-sphere wakes, from those dominated by internal lee waves at
F=1, to
initially fully turbulent early wakes at F[ges ]4. At late times, the
local Froude number
is always low, and a characteristic stratified wake structure and dynamics result.
These wakes have high mean wake defect velocities compared with non-stratified
wakes, but the decay rates of energy and enstrophy are similar. Experimental
evidence is presented for the existence of an intermediate non-equilibrium
(NEQ)
regime with very low decay rates of kinetic energy, that precedes the late wake.
The NEQ regime is the period when the initial turbulence reorganizes
under the
increasingly (relative to the decaying turbulent kinetic energy) powerful
influence of
the background density gradient, accompanied by conversion of potential to kinetic
energy as the wake turbulence collapses. The stable long-lived late-wake structure
that eventually emerges has a high degree of order and coherence that reflects the
initial wake instability. A universal curve for the energy decay of all
stratified drag wakes at high Froude and Reynolds numbers is proposed.
Perturbation dynamics in viscous channel flows
Authors: CRIMINALE W. O. , JACKSON T. L. , LASSEIGNE D. G. , JOSLIN R. D.
Published: July 2002

Plane viscous channel flows are perturbed and the ensuing initial-value
problems are
investigated in detail. Unlike traditional methods where travelling wave
normal modes
are assumed as solutions, this work offers a means whereby arbitrary initial
input can
be specified without having to resort to eigenfunction expansions. The full temporal
behaviour, including both early-time transients and the long-time asymptotics, can
be determined for any initial small-amplitude three-dimensional disturbance. The
bases for the theoretical analysis are: (a) linearization of the governing
equations; (b)
Fourier decomposition in the spanwise and streamwise directions of the flow;
and (c)
direct numerical integration of the resulting partial differential equations.
All of the
stability criteria that are known for such flows can be reproduced. Also,
optimal initial
conditions measured in terms of the normalized energy growth can be determined
in a straightforward manner and such optimal conditions clearly reflect transient
growth data that are easily determined by a rational choice of a
basis for the initial
conditions. Although there can be significant transient growth for subcritical values
of the Reynolds number, it does not appear possible that arbitrary initial conditions
will lead to the exceptionally large transient amplitudes that
have been determined by
optimization of normal modes when used without regard to a particular initial-value
problem. The approach is general and can be applied to other classes of problems
where only a finite discrete spectrum exists (e.g. the Blasius boundary layer).
Finally, results from the temporal theory are compared with the equivalent
transient test case
in the spatially evolving problem with the spatial results having been obtained using
both a temporally and spatially accurate direct numerical simulation code.
Experimental study of the stability of boundary-layer flow along a
heated,
inclined plate
Authors: ZUERCHER E. J. , JACOBS J. W. , CHEN C. F.
Published: July 2002

Experiments are conducted to study the longitudinal vortices that
develop in the
boundary layer on the upper surface of an inclined, heated plate. An isothermal
plate
in water is inclined at angles ranging from 20 to 60 degrees (from the
vertical) while the
temperature difference is varied from 2 to 23°C. A double-pass Schlieren
system is
used to visualize the vortices and particle image velocimetry (PIV) is
used to measure
velocities. In addition, a unique method is developed such that both the
Schlieren
visualization and PIV can be performed simultaneously. The wavelengths
of the
vortices and the critical modified Reynolds numbers (R˜)

for the onset, merging, and
breakup of the vortices are determined from Schlieren images for Pr=5.8.
The critical
values for R˜ and the critical wavelengths are compared
to results of previous
experiments and stability analyses. The spatial growth rates of vortices
are determined
by using the PIV measurements to determine how the circulation in the vortices
grows
with distance from the leading edge. This is the first time that the growth
rate of the
vortices have been found using velocity measurements. These spatial growth
rates are
compared to the results of Iyer & Kelly (1974) and found to be in general
agreement.
By defining a suitable circulation threshold, the critical R˜

for the onset of the vortices can be found from the growth curves.
Flow through a charged biopolymer layer
Authors: MOKADY A. J. , MESTEL A. J. , WINLOVE C. P.
Published: July 2002

The polyelectrolyte layer coating mammalian cells, known as the
glycocalyx, is
important in communicating flow information to the cell. In this paper,
the layer is
modelled as a semi-infinite, doubly periodic array of parallel charged
cylinders. The
electric potential and ion distributions surrounding such an array are
found using
the Poisson–Boltzmann equation and an iterative domain decomposition
technique.
Similar methods are used to calculate Stokes flows, driven either by a
shear at infinity
or by an electric field, parallel or transverse to the cylinders. The resulting

electric streaming currents due to flow over endothelial cells, and the
electrophoretic
mobilities of red blood cells are deduced as functions of polymer concentration
and
electrolyte molarity. It is shown that only the top portion of the layer
is important in
these effects.
Laboratory studies of double-diffusive sources in closed regions
Authors: TURNER J. S. , VERONIS G.
Published: July 2002

Various observations of layering and intrusions in the ocean strongly suggest that such
structures and motions are produced and driven by horizontal and vertical gradients
of temperature and salinity, i.e. by double-diffusive processes. Much of the laboratory
work in this field has concentrated on one-dimensional problems, with the neglect
of two-dimensional phenomena. The latter are addressed explicitly in the present
paper, using the salt–sugar analogue system in a simple geometry, but with the aim
of establishing some more widely applicable general principles. Two sources of salt or
sugar solution were fed in at opposite ends of a 750 mm long tank, with an overflow
tube drawing fluid from a point at the centre of the tank. With two salt sources
of different concentrations and densities, a stratification built up through the ‘filling
box’ process, and the total density range lay within that of the input solutions. For
one salt and one sugar source, a much larger density gradient could be set up, with
the range lying outside that of the inputs. The flows were monitored using various
experimental techniques: photographs of dye streaks with still and video cameras; a
polarimeter to monitor sugar concentration; and the withdrawal of samples for the
measurement of density and refractive index, from which the separate contributions
of salt and sugar to the density could be calculated.

Three related experiments with simple input conditions were particularly instructive,
and these will be described first. Both inputs and the withdrawal tube were located
at mid-depth, and the tank fluid and the salt and sugar supplies had the same
density. The only difference between runs was the initial composition of the solution
in the tank: pure salt, pure sugar, and a 50[ratio ]50 mixture of the two. Following an
initial transient response which was different in the three experiments, they all tended
to the same asymptotic distributions of salt, sugar and density after about 100 h,
with a sharp central interface and weakly stratified upper and lower layers. This
state corresponded approximately to the one-dimensional ‘rundown’ of a layer of
salt solution above sugar solution, with a slightly higher, unstable concentration of
salt in the top layer compared to the bottom and a very stable sugar distribution,
with a much larger concentration in the bottom layer than in the top one. This
distribution cannot be produced by ‘finger’ rundown, and it corresponds to the
maximum release of potential energy. It was, however, achieved through the action of
many intrusions, which remained active in the dynamic final state, and maintained a
strong communication between the two ends of the tank. A comparable experiment
was carried out using a tank 1820 mm long. With this larger aspect ratio there was
a predominantly local influence of the sources at each end of the tank. Other runs
have explored a variety of geometries of the sources and sinks, and the final state has
been shown to be sensitive to these boundary conditions.
A note on the instabilities of a horizontal shear flow with a free surface
Authors: ENGEVIK L.
Published: July 2002

The instabilities of a free surface shear flow are considered, with special emphasis on
the shear flow with the velocity profile
U* = U*0sech2 (by*). This velocity profile, which
is found to model very well the shear flow in the wake of a hydrofoil, has been focused
on in previous studies, for instance by Dimas & Triantyfallou who made a purely
numerical investigation of this problem, and by Longuet-Higgins who simplified the
problem by approximating the velocity profile with a piecewise-linear profile to make
it amenable to an analytical treatment. However, none has so far recognized that this
problem in fact has a very simple solution which can be found analytically; that is, the
stability boundaries, i.e. the boundaries between the stable and the unstable regions
in the wavenumber (k)–Froude number (F)-plane, are given by simple algebraic
equations in k and F. This applies also when surface tension is included. With no
surface tension present there exist two distinct regimes of unstable waves for all values
of the Froude number F > 0. If 0 < F [Lt ] 1, then one of the regimes is given by
0 < k < (1 − F2/6), the other by
F−2 < k < 9F−2, which is a
very extended region on the k-axis. When F [Gt ] 1 there is one small unstable
region close to k = 0, i.e. 0 < k < 9/(4F2),
the other unstable region being
(3/2)1/2F−1 < k < 2 + 27/(8F2).
When surface tension is included there may be one, two or even three distinct regimes
of unstable modes depending on the value of the Froude number. For small F there
is only one instability region, for intermediate values of F there are two regimes of
unstable modes, and when F is large enough there are three distinct instability regions.
State Agrarianism versus Democratic Agrarianism: Adalberto Tejeda's

Experiment in Veracruz, 1928–32
Authors: GINZBERG EITAN
Published: July 2002

This article analyses Adalberto Tejeda's agrarian experiment
in the state
of Veracruz, Mexico, during the years 1928–32. This experiment was
unique in
two respects. First, disregarding the central government's policy,
which sought
to end agrarian distribution completely, it parcelled out land to the peasants
on
an unprecedented scale; secondly, it proved, contrary to the prevailing
wisdom
of the time, that agrarian reform implemented through the full range of
channels
offered by the 1917 federal constitution could serve as a tool of social
justice and
equality, and hence as a central factor in the advancement of social welfare
and
democracy in Mexico. This article seeks to show that the failure of the
Veracruz
experiment offers an explanation – perhaps a cardinal explanation
– for the
perceived failure of Mexican agrarian reform in general.
A link between predator density and arm loss in the starfish Marthasterias glacialis and Asterias rubens
Authors: Ramsay Kirsten , Turner John R. , Vize Samantha J. , Richardson Christopher A.
Published: July 2002

Arm loss in two species of starfish Marthasterias glacialis and Asterias rubens (Echinodermata: Asteroidea) was recorded at eight sites in Lough Hyne, south-west Ireland. There was a significant positive correlation between the density of predators (Luidia ciliaris (Echinodermata: Asteroidea) and Cancer pagurus (Crustacea: Brachyura)) and arm loss in both species of starfish. The results suggest that predators may be responsible for a significant proportion of observed arm loss in these two species of starfish in Lough Hyne.
Reproduction in British zoanthids, and an unusual process in Parazoanthus anguicomus
Authors: Ryland J.S.
Published: July 2002

Specimens of three zoanthid species, Epizoanthus couchii, Parazoanthus anguicomus and P. axinellae were sectioned. All were gonochoric, with gametes developing during summer. Oocytes in P. anguicomus originate in a single-layered ribbon down the perfect septa, but the ribbon becomes moniliform as, at regular intervals, it folds laterally into lens-shaped nodes, packed with oocytes, doubling polyp fecundity.
Larval development of the intertidal barnacles Chthamalus stellatus and Chthamalus montagui
Authors: Burrows M.T. , Hawkins S.J. , Southward A.J.
Published: July 2002

Two recently-distinguished species of Chthamalus (Cirripedia) are found on rocky shores in the north-eastern Atlantic: C. stellatus predominant on islands and headlands and C. montagui more abundant in bays. Larvae of the two species were produced in laboratory cultures to describe and compare the morphology and to allow identification in plankton samples. Nauplius larvae of C. stellatus are up to 30% larger than those of C. montagui. Differences in setation are minor. The two species are easily distinguishable from the size and shape of the cephalic shield. Chthamalus stellatus has a subcircular shield with longer body processes in later stages while C. montagui is more ovoid. The former develop more slowly in culture than the latter. Chthamalus stellatus larvae in a culture at 19 °C reached stage VI in 16 d compared to 11 d for larvae of C. montagui at the same temperature. The morphology and longer development time of C. stellatus larvae suggests adaptation to a more oceanic lifestyle and wider dispersal to reach more fragmented habitats than larvae of C. montagui.
Observations of the echiuran worm Bonellia viridis in the deep basin of the northern Evoikos Gulf, Greece
Authors: Hughes D.J. , Marrs S.J. , Smith C.J. , Atkinson R.J.A.
Published: July 2002

Towed underwater TV observations at 440 m in the northern Evoikos Gulf, Greece, revealed a soft mud plain heavily bioturbated by the thalassinidean Calocaris macandreae, with Callianassa subterranea and Nephrops norvegicus also present. Ejecta mounds and feeding traces indicated the presence of a large echiuran, provisionally identified as Maxmuelleria gigas. The locality also supported a dense population of a second echiuran, Bonellia viridis, a species not previously recorded as an inhabitant of sedimentary environments.
Diet of common dolphins, Delphinus delphis, off the Portuguese continental coast
Authors: Silva M.A.
Published: July 2002

Diet of common dolphins off the Portuguese coast was studied based on the examination of stomach contents of 50 stranded and incidentally caught animals. The relative importance of each prey species was assessed through occurrence, numerical and biomass indices. Common dolphins preyed on a large variety of items but four fish and two cephalopod species appeared to form the basis of their diet. Overall, sardine (Sardina pilchardus) was the most important prey, as given by all the indices used to measure prey relative importance. Although common dolphins preyed mostly on pelagic species, they seemed able to explore habitats with distinct features and employ various foraging strategies. A comparison between the diet of dolphins of different sex and size groups was not indicative of major differences. Common dolphins incidentally caught in fishing nets had taken a higher proportion of sardines, the target species of the fishery.
A partial review of the European Magelonidae (Annelida: Polychaeta): Magelona mirabilis redefined and M. johnstoni sp. nov. distinguished
Authors: Fiege Dieter , Licher Frank , Mackie Andrew S Y
Published: July 2002

The identification of magelonids with mucronate chaetae on chaetiger 9 has long been confused. Until 1977 all corresponding European specimens were erroneously referred to Magelona papillicornis; a Brazilian species. Since then, but without any detailed study, the name M. mirabilis (originally given to a species from Scotland) has been widely employed. However, in recent years, it has become clear that two morphologically similar species coexist in European waters. Magelona mirabilis is redescribed and a neotype designated, and M. johnstoni sp. nov. is formally distinguished. Following re-examination of the other five species present in the region, a dichotomous key and a synoptic table of characters is provided for all seven European species.
Chlorophyll-a and primary production during spring in the oceanic region of the Oyashio Water, the north-western Pacific
Authors: Shiomoto Akihiro
Published: July 2002

The concentration of phytoplankton chlorophyll-a (chl-a) and primary production within the euphotic zone (at depths corresponding to 100, 30, 10 and 2% light) were measured in the oceanic region of the Oyashio Water, the north-western Pacific, in spring of 1993, 1994 and 1995. The chl-a concentrations ranged from 0.15 to 6.98 mg m−3 and the range of chl-a standing stock integrated from the surface to the 2% light depth was between 4 and 43 mg m−2. The daily primary production integrated from the surface to the 2 and 0.2% light depths was estimated to be between 94 and 1695 mg C m−2 d−1 and between 114 and 2046 mg C m−2 d−1, respectively. Phytoplankton bloom was noticed when the depths of the euphotic zone and the upper mixed layer were similar. The maximum chl-a concentration and daily primary production in the upper 0.2% light depth were comparable to those reported previously in the spring bloom in the coastal, offshore and oceanic regions of the Oyashio Water, and in the summer bloom of the Western Subarctic Gyre in the North Pacific. The magnitude of daily primary production in the phytoplankton bloom in the western subarctic North Pacific (the Oyashio Water and the Western Subarctic Gyre) was comparable with those in the eastern subarctic North Pacific and the subarctic North Atlantic. The magnitude of chl-a in the phytoplankton bloom in the western subarctic North Pacific was higher than those in the other subarctic regions. Varied contribution of large diatoms to the phytoplankton biomass, caused by different iron and silicate conditions was hypothesized to be a leading factor for variation in magnitude of the phytoplankton biomass.
The Pursuit of Persian: Language in Mughal Politics
Authors: ALAM MUZAFFAR
Published: July 2002

The Mughal literary culture has been noted for its notable achievements in poetry and a wide range of prose writings in Persian. In terms of profusion and variety of themes this literary output was also perhaps incomparable. The court's patronage has rightly been suggested as an important reason for this. This patronage, however, was not consistent throughout; much of the detail of its detour thus requires a closer scrutiny. The phenomenal rise of the language defies explanation in the first instance. The Mughals were Chaghtā'i Turks and we know that, unlike them, the other Turkic rulers outside of Iran, such as the Ottomans in Turkey and the Uzbeks in Central Asia, were not so enthusiastic about Persian. Indeed, in India also, Persian did not appear to hold such dominance at the courts of the early Mughals. In his memoir, Bābur (d. 1530), the founder of the Mughal empire in India, recounted the story of his exploits in Turkish. The Prince was a noted poet and writer of Turkish of his time, second only to ‘Alī Sheēr Nawā’ī (d. 1526). Turkish was the first language of his son and successor, Humāyūn (d. 1556), as well.
A phylogenetic analysis of filarial nematodes: comparison with the phylogeny of Wolbachia endosymbionts
Authors: CASIRAGHI M. , ANDERSON T.J.C. , BANDI C. , BAZZOCCHI C. , GENCHI C.
Published: July 2002

Infection with the endosymbiotic bacteria Wolbachia is widespread in filarial nematodes. Previous studies have suggested concordance between the phylogeny of Wolbachia with that of their nematode hosts. However, there is only one published molecular phylogenetic study of filarial species, based on the 5S rRNA gene spacer. The phylogeny proposed by this study is partially incongruent with previous classifications of filarial nematodes, based on morphological characters. Furthermore, both traditional classifications and molecular phylogenies are, in part, inconsistent with the phylogeny of Wolbachia. Here we report mitochondrial cytochrome oxidase I (COI) gene sequences for 11 species of filaria and for another spirurid nematode which was included as an outgroup. In addition, 16S rRNA, wsp and ftsZ gene sequences were generated for the Wolbachia of several filarial species, in order to complete the available data sets and further resolve the phylogeny of Wolbachia in nematodes. We used these data to evaluate whether nematode and Wolbachia phylogenies are concordant. Some of the possible phylogenetic reconstructions based on COI gene were congruent with the phylogeny of Wolbachia and supported the grouping of the rodent filaria Litomosoides sigmodontis with the lymphatic filariae (i.e. Brugia spp. and Wuchereria spp.) and the sister group relationship of Dirofilaria spp. and Onchocerca spp. However, the placement of the Wolbachia-free filaria Acanthocheilonema viteae is ambiguous and dependent on the phylogenetic methods used.
Compatibility and sex in a snail–schistosome system
Authors: WEBSTER J. P.
Published: July 2002

Knowledge of the genetics underlying resistance to parasitic infection has important repercussions for our understanding of infection dynamics and the mechanisms of host–parasite co-evolution. The aim here was to determine for a Biomphalaria glabrata–Schistosoma mansoni system whether (1) resistance is dominant over susceptibility, (2) it is possible to crossbreed snails to be simultaneously resistant and/or susceptible to more than one parasite strain and (3) compatibility genotype affects reproductive strategy. Using replicate snail strains artificially selected for either resistance or susceptibility to single replicate parasite strains, individual snails from each line were paired with a selected partner of matched or non-matched compatibility status and cross-breeding was identified by RAPD–PCR. The resulting compatibility phenotype of all offspring was determined. Support for all 3 hypotheses were obtained. The results are discussed in terms of their applied and theoretical implications.
Immunoepidemiology of the equine tapeworm Anoplocephala perfoliata:
age-intensity profile and age-dependency of antibody subtype responses
Authors: PROUDMAN C. J. , HOLMES M. A. , SHEORAN A. S. , EDWARDS S. E. R. , TREES A. J.
Published: July 2002

The equine intestinal cestode Anoplocephala perfoliata
has been the subject of recent epidemiological and immunological studies
because of its suspected association with intestinal disease in the horse.
We have previously shown that the IgG(T) subtype antibody response to the
12/13 kDa component of the parasite excretory/secretory (E/S)
antigen is positively correlated with parasite intensity. In this study,
we utilize that correlation to examine the changes in natural infection
intensity with age. Infection intensity based on IgG(T) responses showed
a triphasic age-dependency pattern with peak mean worm burden in the 6
months–2 years age group, falling to a lower plateau level from 3
to 15 years, and rising again in older age groups. Anti-E/S total IgG
was found to have a convex age-dependency curve, with maximal response
in the 6 months–2 years old age group. IgG(a) showed a triphasic
response similar to the age-intensity profile of IgG(T); IgG(c) showed
steadily increasing levels of antibody with age. The IgG(b) age-dependency
profile was intermediate between IgG(a) and IgG(c). Age-specific correlation
coefficients between anti-12/13 kDa IgG(T) (as a measure of infection
intensity) and IgG(a) and IgG(b) revealed statistically significant values
for many age groups. The relative importance of exposure to infection and
the development of acquired immunity as determinants of the observed age-intensity
pattern is considered.
The effect of concurrent or sequential Oesophagostomum

dentatum and O. quadrispinulatum infections on the worm

burdens of the two species in pigs
Authors: CHRISTENSEN C. M. , NANSEN P. , BARNES E. H.
Published: July 2002

The interaction between the 2 nodular worm species in the

pig, Oesophagostomum dentatum (O.d.) and Oesophagostomum

quadrispinulatum (O.q.), was studied by comparing the development

and distribution of the species following single or

mixed infections. The faecal egg excretion levels were assessed at regular

intervals from week 3 post-inoculation, and

indicated a strong negative impact of the introduction of O.q.
on the

continued egg excretion of O.d. All pigs were killed

9 weeks after the first inoculations to determine the composition and

location of the worm burdens in the large intestine.

O.q. was found more anteriorly located in the intestine than

O.d., thus confirming previous descriptions. When both

species were present, the distribution of O.d. was moved

further posteriorly and was more spread out than in single-species infections.

There appeared to be no adverse effect of O.d. on the establishment

and fecundity of O.q. However, the worm recoveries corroborated
the egg

excretion observations, namely reduced worm burdens of O.d. if

O.q. was introduced, or if O.q. was already present.
It is

uncertain whether this effect is caused by differences in host reaction

against the two species, or whether a more specific competition occurs

between the two nodular worm species in pigs.
Ectoparasites of the whitespotted rabbitfish, Siganus sutor

(Valenciennes, 1835) off the Kenyan Coast: distribution

within the host population and site selection on the gills
Authors: GEETS A. , COENE H. , OLLEVIER F.
Published: July 2002

Different populations of the whitespotted rabbitfish, Siganus

sutor, were examined for ectoparasites: adults from the

Mombasa area (sampled in December 1990) and different age classes (adult,

subadult and juveniles) from Gazi Bay

(sampled in December 1992 and August 1993). The most common gill parasites

were: the monogeneans Pseudohaliotrema

sp., Tetrancistrum sigani and Microcotyle mouwoi,

the copepods Hatschekia sp., Pseudolepeophtheirus

sp. and juvenile

Caligidae, and prazina larvae of the isopod Gnathia sp. Adult
siganids

had a higher parasite load than subadults. Juvenile

rabbitfish did not harbour any gill parasites. Temporal differences in
the

parasite load of subadult rabbitfish were observed

for M. mouwoi (highest in the December samples) and for juvenile

Caligidae (highest in August). The microhabitat of the

5 most common gill parasites was species specific. Most parasite species

showed distinct site preferences with respect to

both gill arches and gill sectors, within the gill arches. Niche

breadth of the different gill parasite species was independent

of the abundance of any of the other species present. However, niche

breadths of M. mouwoi, Tetrancistrum sp. and

Hatschekia sp. increased with their own abundance. This suggests

that interspecific competition for space is low and that

intraspecific factors could play an important role in the microhabitat

choice of these gill parasites. The hypothesis that

niche restriction leads to higher intraspecific contact and an

enhancement of chances to mate was tested on 2 monogenean

species, Pseudohaliotrema sp. and Tetrancistrum sigani.

Their highly aggregated distribution over the gill filaments, leading

to increased intraspecific contact, is consistent with the hypothesis.
Comparative sequence analysis of 5·8S rRNA genes and
internal transcribed spacer (ITS) regions of trichomonadid protozoa
Authors: FELLEISEN R. S. J.
Published: July 2002

The taxonomic situation in the genus Tritrichomonas is
the
subject of controversial discussion: potentially T. foetus and
T. suis, the tritrichomonads from cattle and swine, respectively,
could belong to the same species. In order to shed some
light on this question, a molecular biological analysis was performed.
The
5·8S rRNA gene and the flanking internal
transcribed spacer regions (ITS1 and ITS2) of 12 different isolates of
3
Tritrichomonas species T. foetus, T. suis and
T.
mobilensis were enzymatically amplified by PCR and subcloned. Also,
the
corresponding regions of the trichomonads
Trichomonas vaginalis, T. tenax, T. gallinae
and
Pentatrichomonas hominis were included in this study. Sequence
analysis
of cloned fragments was used to compare the parasite isolates. The genus
Tritrichomonas exhibited an extremely high
degree of homogeneity. All T. foetus and T. suis isolates
had identical sequences, and only 1 substitution was found in the
ITS2 region of T. mobilensis. In contrast, the genus Trichomonas
shared more diversity. The results obtained in this study
support a possible future revision of the taxonomic classification of
tritrichomonads.
Isolation and characterization of secretions from the
plant-parasitic nematode Globodera pallida
Authors: DUNCAN L. H. , ROBERTSON L. , ROBERTSON W. M. , KUSEL J. R.
Published: July 2002

Electrophoresis of secretions collected from Globodera
pallida revealed a smeared region between 25 and 50 kDa, and a
single band of <20 kDa. The secretions were used to raise an antiserum
(LW1). Immunoblotting of parasite homogenates
with LW1 differentiated G. pallida from its sibling species
G. rostochiensis and revealed differences between different
populations of G. pallida and G. rostochiensis.
Indirect immunofluorescence studies with LW1 indicated that at least some
of the secretions were surface localized and that antibody binding to the
nematode surface was periodate sensitive.
Periodate sensitivity indicated that these differences could be due to
glycosylation differences. Glycosylation differences
were also detected by blotting nematode homogenates with the lectin wheat
germ agglutinin (WGA). WGA was also able
to differentiate between G. rostochiensis which gave 2 bands at
130 kDa and 110 kDa, and G. pallida which produced 2
bands present at 120 kDa and 110 kDa. Further localization studies
using immunoelectron microscopy demonstrated that
antibody binding could be seen to secretions found in the pump chamber
of
the metacorpal bulb at the base of the stylet.
From further specimens it could be observed that the contents of the
subventral glands were heavily labelled, indicating
that the material seen in the metacorpal bulb had originated from the
subventral glands.
Cercaria–schistosomulum surface transformation of

Trichobilharzia szidati and its putative immunological

impact
Authors: HORÁK P. , KOVÁŘ L. , KOLÁŘOVÁ L. , NEBESÁŘOVÁ J.
Published: July 2002

Schistosome cercariae of the genus

Trichobilharzia are the causative agent of

swimmers' itch. In order to characterize the

changes in parasites during and after the penetration of the

host skin, in vitro and in vivo (in

ducks and mice) transformations of T. szidati

cercariae to schistosomula were performed. Ultrastructural

observation revealed that cercariae

possess a simple outer tegumental membrane with a thick

glycocalyx. As with human schistosomes, the latter structure

disappears during transformation and a new double membrane

with putative protective function is formed. Our biochemical

and immunological observations showed that the carbohydrate-rich

glycocalyx of cercariae is readily bound by

lectins and antibodies. The in vitro transformation

to schistosomula can be detected by enhanced reactivity of 2 lectin

probes (PNA and ConA) with the surface. The

in vivo-transformed (skin and lung) schistosomula

appear to have few

surface ligands for the 12 lectin probes being tested.

Similarly, the cercarial surface and its remnants on the

in vitro-produced schistosomula is recognized by sera

from immunized mice and humans with cercarial dermatitis;

the tissue schistosomula fail to react with these antibodies.

The loss of surface targets as a part of parasite immune

evasion within the host is discussed.
Molecular characterization of a Toxocara variant from cats
in Kuala Lumpur, Malaysia
Authors: ZHU X. Q. , JACOBS D. E. , CHILTON N. B. , SANI R. A. , CHENG N. A. B. Y. , GASSER R. B.
Published: July 2002

The ascaridoid nematode of cats from Kuala Lumpur, Malaysia,
previously identified morphologically as Toxocara canis,
was characterized using a molecular approach. The nuclear ribosomal
DNA (rDNA) region spanning the first internal
transcribed spacer (ITS-1), the 5·8S gene and the second
internal transcribed spacer (ITS-2) was amplified and sequenced.
The sequences for the parasite from Malaysian cats were compared with
those for T. canis and T. cati. The sequence data
showed that this taxon was genetically more similar to T. cati

than to T. canis in the ITS-1, 5·8S and ITS-2. Differences

in the ITS-1 and ITS-2 sequences between the taxa
(9·4–26·1%) were markedly higher than variation between
samples
within T. canis and T. cati (0–2·9%).
The sequence data demonstrate that the parasite from Malaysian cats is
neither T.
canis nor T. cati and indicate that it is a distinct
species. Based on these data, PCR-linked restriction fragment length
polymorphism (RFLP) and single-strand conformation polymorphism (SSCP)
methods
were employed for the unequivocal differentiation of the
Toxocara variant from T. canis and T. cati.

These methods should provide valuable tools
for studying the life-cycle, transmission pattern(s) and zoonotic potential
of this parasite.
Larval survival characteristics and behaviour of the gill
monogenean Discocotyle sagittata
Authors: GANNICOTT A. M. , TINSLEY R. C.
Published: July 2002

The survival characteristics of Discocotyle sagittata
larvae are both age- and temperature-dependent. In laboratory studies
at constant temperatures of 6, 10, 13, 18 and 22°C, oncomiracidia had
a maximum life-span of 96 h at 6°C, declining with
increasing temperature to 26 h at 22°C. Larval swimming activity was
also age dependent, and continued for a large
proportion of survival time. The relationship between time at which larvae
stop swimming as a proportion of total survival
time was statistically significant between temperatures. Proportionally,
oncomiracidia swam for longer periods at lower
temperatures. As oncomiracidia age, they become progressively less active,
spending less time in the water column. In
contrast to observations recorded in the literature, D. sagittata
larvae are infective soon after emergence (within the
minimum of 2 h studied), and feed on blood from the gill capillaries within
2 h post-exposure. The temperature-dependent
characteristics of the larval stage are likely to have important implications
for seasonal changes in parasite transmission.
The ancient and divergent origins of the human
pathogenic trypanosomes, Trypanosoma brucei and T. cruzi
Authors: STEVENS J. R. , NOYES H. A. , DOVER G. A. , GIBSON W. C.
Published: July 2002

This study presents new findings concerning the evolution of the
human pathogens, Trypanosoma brucei and T. cruzi,
which suggest that these parasites have divergent origins and fundamentally
different patterns of evolution. Phylogenetic
analysis of 18S rRNA sequences places T. brucei in a clade comprising
exclusively mammalian trypanosomes of African
origin, suggesting an evolutionary history confined to Africa. T. cruzi
(from humans and sylvatic mammals) clusters with
trypanosomes specific to Old and New World bats, T. rangeli and
a trypanosome species isolated from an Australian
kangaroo. The origins of parasites within this clade, other than some of
those from bats, lie in South America and Australia
suggesting an ancient southern super-continent origin for T. cruzi,
possibly in marsupials; the only trypanosomes from
this clade to have spread to the Old World are those infecting bats, doubtless
by virtue of the mobility of their hosts.
Viewed in the context of palaeogeographical evidence, the results date
the divergence of T. brucei and T. cruzi to the
mid-Cretaceous, around 100 million years before present, following the
separation of Africa, South America and Euramerica.
The inclusion in this study of a broad range of trypanosome species from
various different hosts has allowed long
phylogenetic branches to be resolved, overcoming the limitations of many
previous studies. Moreover, T. brucei and the
other mammalian tsetse-transmitted trypanosomes appear, from these data,
to be evolving several times faster than T.
cruzi and its relatives.
Genetic variation and epidemiology of
Echinococcus granulosus in Argentina
Authors: ROSENZVIT M. C. , ZHANG L.-H. , KAMENETZKY L. , CANOVA S. G. , GUARNERA E. A. , McMANUS D. P.
Published: July 2002

Polymerase chain reaction–ribosomal ITS-1 DNA (rDNA) restriction fragment length polymorphism (PCR–RFLP)
analysis and sequencing of the mitochondrial cytochrome c oxidase subunit 1 (CO1) and NADH dehydrogenase 1 (ND1)
genes were used to characterize 33 Echinococcus granulosus isolates collected from different regions and hosts in Argentina,
and to determine which genotypes occurred in humans with cystic hydatid disease. The results of the study demonstrated
the presence of at least 4 distinct genotypes; the common sheep strain (G1) in sheep from Chubut Province and in humans
from Río Negro Province, the Tasmanian sheep strain (G2) in sheep and 1 human from Tucumán Province, the pig strain
(G7) in pigs from Santa Fe Province and the camel strain (G6) in humans from Río Negro and Buenos Aires Provinces.
The finding that pigs harboured the pig strain and the occurrence of the Tasmanian sheep strain has considerable
implications for the implementation of hydatid control programmes due to the shorter maturation time of both strains in
dogs compared with the common sheep strain. Furthermore, this is the first report of the presence of the G2 and G6
genotypes in humans which may also have important consequences for human health.
Enhancement of apoptosis with loss of cellular adherence
in the villus epithelium of the small intestine after
infection with the nematode Nippostrongylus brasiliensis
in rats
Authors: HYOH Y. , NISHIDA M. , TEGOSHI T. , YAMADA M. , UCHIKAWA R. , MATSUDA S. , ARIZONO N.
Published: July 2002

It has been reported that infection with Nippostrongylus brasiliensis induces villus atrophy with various histological
alterations. In N. brasiliensis-infected rats, villus length in the jejunum was reduced significantly at day 10 p.i., when
serum levels of rat mast cell protease (RMCP) II had increased significantly. To determine whether the villus atrophy is
associated with enhancement of apoptosis, apoptotic nuclei were labelled using the nick end-labelling method. Numbers
of labelled cells were markedly increased in the villus epithelium at 7–10 days p.i., while the numbers returned to normal
14 days p.i. when worms were rejected from the intestine and villus length became normal. Examination of the expression
of the adhesion molecule E-cadherin showed granular immunoreactivity in the cytoplasm of atrophic villus epithelium
with loss of normal localization to epithelial cell borders. In mast cell-deficient Ws/Ws rats, villus length was reduced as
significantly as in +/+ counterparts at day 10 p.i. with marked increases in the numbers of apoptotic cells. These results
suggested that villus atrophy was closely associated with enhanced apoptosis and loss of adhesion in epithelial cells. Mast
cell activation appears not to be involved in these alterations.