bluuebunny/crossref_metadata_2025 huggingface dataset:
An experimental investigation of screech noise generation
Authors: PANDA J.
Published: July 2002

The screech noise generation process from supersonic underexpanded
jets, issuing
from a sonic nozzle at pressure ratios of 2.4 and 3.3 (fully expanded Mach
number,
Mj=1.19 and 1.42), was investigated experimentally.
The extremely detailed data
provide a fresh, new look at the screech generation mechanism. Spark schlieren

visualization at different phases of the screech cycle clearly shows the
convection of
the organized turbulent structures over a train of shock waves. The potential
pressure
field (hydrodynamic fluctuations) associated with the organized structures
is fairly
intense and extends outside the shear layer. The time evolution of the
near-field
pressure fluctuations was obtained from phase-averaged microphone measurements.

Phase-matched combined views of schlieren photographs and pressure fluctuations

show the sound generation process. The individual compression and rarefaction

parts of the sound waves are found to be generated from similar hydrodynamic

fluctuations. A partial interference between the upstream-propagating sound
waves
and the downstream-propagating hydrodynamic waves is found to be present
along
the jet boundary. The partial interference manifests itself as a standing
wave in the
root-mean-square pressure fluctuation data. The standing wavelength is
found to
be close to, but somewhat different from, the shock spacing. An outcome
of the
interference is a curious ‘pause and go’ motion of the sound
waves along the jet
periphery. Interestingly, a length scale identical to the standing wavelength
is found
to be present inside the jet shear layer. The coherent fluctuations and
the convective
velocity of the organized vortices are found to be modulated periodically,
and the
periodicity is found to match with the standing wavelength distance rather
than the
shock spacing. The reason for the appearance of this additional length
scale, different
from the shock spacing, could not be explained. Nevertheless, it is demonstrated

that an exact screech frequency formula can be derived from the simple
standing
wave relationship. The exact relationship shows that the correct spacing
between
the sources, for a point source model similar to that of Powell (1953),
should be a
standing wavelength (not the shock spacing).
The long-time impulse response of compressible
swept-wing boundary layers
Authors: TAYLOR M. J. , PEAKE N.
Published: July 2002

Following the investigation of the long-time limit of the impulse
response of an
incompressible swept boundary layer (Taylor & Peake 1998), we now consider
the
corresponding behaviour of two representative sets of compressible swept-wing
profiles,
one set in subsonic flow and the other in supersonic flow. The key feature
of the
incompressible analysis was the occurrence of modal pinch points in the
cross-flow
wavenumber plane, and in this paper the existence of such pinches over
a wide
portion of space in high-speed flow is confirmed. We also show that close
to the attachment
line, no unstable pinches in the chordwise wavenumber plane can be found

for these realistic wing profiles, contrary to predictions made previously
for
incompressible flow with simple Falker–Skan–Cooke profiles
(Lingwood 1997). A method
for searching for absolute instabilities is described and applied to the
compressible
boundary layers, and we are able to confirm that these profiles are not
absolutely
unstable. The pinch point property of the compressible boundary layers
is used here
to predict the maximum local growth rate achieved by waves in a wavepacket
in
any given direction. By determining the direction of maximum amplification,
we
are able to derive upper bounds on the amplification rate of the wavepacket
over
the wing, and initial comparison with experimental data shows that the
resulting
N-factors are more consistent than might be expected from existing conventional

methods.
The role of ‘splashing’ in the collapse of a
laser-generated cavity near a rigid boundary
Authors: TONG R. P. , SCHIFFERS W. P. , SHAW S. J. , BLAKE J. R. , EMMONY D. C.
Published: July 2002

Vapour cavities in liquid flows have long been associated with
cavitation damage to
nearby solid surfaces and it is thought that the final stage of collapse,
when a high-
speed liquid jet threads the cavity, plays a vital role in this process.
The present study
investigates this aspect of the motion of laser-generated cavities in a
quiescent liquid
when the distance (or stand-off) of the point of inception from a rigid
boundary is
between 0.8 and 1.2 times the maximum radius of the cavity.
Numerical simulations
using a boundary integral method with an incompressible liquid impact model
provide
a framework for the interpretation of the experimental results. It is observed
that,
within the given interval of the stand-off parameter, the peak pressures
measured on
the boundary at the first collapse of a cavity attain a local minimum,
while at the
same time there is an increase in the duration of the pressure pulse. This
contrasts
with a monotonic increase in the peak pressures as the stand-off is reduced,
when
the cavity inception point is outside the stated interval. This phenomenon
is shown
to be due to a splash effect which follows the impact of the liquid jet.
Three cases
are chosen to typify the splash interaction with the free surface of the
collapsing
cavity: (i) surface reconnection around the liquid jet; (ii) splash impact
at the base
of the liquid jet; (iii) thin film splash. Hydrodynamic pressures generated
following
splash impact are found to be much greater than those produced by the jet
impact.
The combination of splash impact and the emission of shock waves, together
with
the subsequent re-expansion, drives the flow around the toroidal cavity
producing a
distinctive double pressure peak.
Topographical scattering of gravity waves
Authors: MILES J. W. , CHAMBERLAIN P. G.
Published: July 2002

A systematic hierarchy of partial differential equations for linear

gravity waves in water
of variable depth is developed through the expansion of the average Lagrangian
in
powers of [mid ]∇[mid ] (h=depth, ∇h=slope).

The first and second members of this
hierarchy, the Helmholtz and conventional mild-slope equations, are second
order.
The third member is fourth order but may be approximated by Chamberlain
& Porter's
(1995) ‘modified mild-slope’ equation, which is second order
and comprises terms in
∇2h and (∇h)2
that are absent from the mild-slope equation. Approximate solutions of

the mild-slope and modified mild-slope equations for topographical scattering
are
determined through an iterative sequence, starting from a geometrical-optics

approximation (which neglects reflection), then a quasi-geometrical-optics

approximation, and on to higher-order results. The resulting reflection

coefficient for a ramp
of uniform slope is compared with the results of numerical integrations
of each of the
mild-slope equation (Booij 1983), the modified mild-slope equation (Porter
& Staziker
1995), and the full linear equations (Booij 1983). Also considered is a
sequence of
sinusoidal sandbars, for which Bragg resonance may yield rather strong
reflection and
for which the modified mild-slope approximation is in close agreement with
Mei's
(1985) asymptotic approximation.
Effect of axial flow on viscoelastic Taylor–Couette instability
Authors: GRAHAM M. D.
Published: July 2002

Viscoelastic flow instabilities can arise from gradients in elastic
stresses in flows
with curved streamlines. Circular Couette flow displays the prototypical
instability
of this type, when the azimuthal Weissenberg number Weθ

is O(ε−1/2), where ε
measures the streamline curvature. We consider here the effect of superimposed

steady axial Couette or Poiseuille flow on this instability. For inertialess
flow of an
upper-convected Maxwell or Oldroyd-B fluid in the narrow gap limit
(ε[Lt ]1), the analysis predicts that the addition of a relatively
weak steady
axial Couette flow (axial Weissenberg number Wez=O(1))

can delay the onset of instability until
Weθ is significantly higher than without axial
flow.
Weakly nonlinear analysis shows
that these bifurcations are subcritical. The numerical results are consistent
with a
scaling analysis for Wez[Gt ]1, which shows

that the critical azimuthal Weissenberg
number for instability increases linearly with Wez.

Non-axisymmetric disturbances are very strongly suppressed, becoming unstable
only when
ε1/2Weθ=
O(We2z). A
similar, but smaller, stabilizing effect occurs if steady axial Poiseuille
flow is added.
In this case, however, the bifurcations are converted from subcritical
to supercritical
as Wez increases. The observed stabilization
is
due to the axial stresses introduced
by the axial flow, which overshadow the destabilizing hoop stress. If only
a weak
(Wez[les ]1) steady axial flow is added, the

flow is actually slightly destabilized. The
analysis also elucidates new aspects of the stability problems for plane
shear flows,
including the exact structure of the modes in the continuous spectrum,
and illustrates
the connection between these problems and the viscoelastic circular Couette
flow.
The Earth's rotation and laminar pipe flow
Authors: DRAAD A. A. , NIEUWSTADT F. T. M.
Published: July 2002

A pipe flow facility with a length of 32 m and a diameter of 40
mm has been designed
in which a laminar flow of water can be maintained for Reynolds numbers
up to
60 000. Velocity measurements taken in this facility show an asymmetric
velocity
profile both in the vertical as well as horizontal direction with velocities
that deviate
strongly from the parabolic Hagen–Poiseuille profile. The cause of
this asymmetry is
traced back to the influence of the Earth's rotation. This is confirmed
by means of
a comparison of the experimental data with the results from a perturbation
solution
and from a numerical computation of the full nonlinear Navier–Stokes
equations. The
physical background of this unforeseen result lies in the fact that a Hagen–Poiseuille

flow is governed by a force equilibrium and inertia forces are everywhere
negligible.
This implies that the Coriolis force can be balanced only by a viscous
force. So even
the small Coriolis force due to the Earth's rotation causes a large
velocity distortion
for a case such as ours where the kinematic viscosity is small.
Laminar–turbulent transition in Poiseuille pipe
flow subjected to periodic perturbation emanating from the wall
Authors: ELIAHOU S. , TUMIN A. , WYGNANSKI I.
Published: July 2002

Transition in fully developed circular pipe flow was investigated
experimentally by
the introduction of periodic perturbations. The simultaneous excitation
of the
azimuthal periodic modes m=+2 and m=−2 was chosen
for detailed analysis.
The experiments were carried out at three amplitudes. At the smallest amplitude
the
disturbances decayed in the direction of streaming. At intermediate input
amplitude
the disturbances amplified initially but then decayed with increasing distance

downstream. Their growth was accompanied by the appearance of higher harmonics.
At
still higher amplitudes transition occurred. A mean velocity distortion
corresponding
to an azimuthal index of m=4 was observed at the intermediate
and at the higher
levels of forcing. When four stationary jets were introduced through the
wall to emulate
a similar mean velocity distortion, transition was observed at smaller
amplitudes
of forcing at modes ±2. Thus, weak longitudinal vortices provide
an added instability
needed to generate a secondary disturbance which, in turn, amplifies the
steady vortical
structures introduced by the jets. Such vortices may also be generated
through
the interaction of time-periodic helical modes.
Direct computation of the sound generated by
vortex pairing in an axisymmetric jet
Authors: MITCHELL BRIAN E. , LELE SANJIVA K. , MOIN PARVIZ
Published: July 2002

The sound generated by vortex pairing in axisymmetric jets is determined
by direct
solution of the compressible Navier–Stokes equations on a computational
grid that
includes both the near field and a portion of the acoustic far field. At
low Mach
number, the far-field sound has distinct angles of extinction
in the range of 60°–70°
from the jet's downstream axis which can be understood by analogy
to axisymmetric,
compact quadrupoles. As the Mach number is increased, the far-field sound
takes on a
superdirective character with the dominant sound directed at shallow angles
to the jet's
downstream axis. The directly computed sound is compared to predictions
obtained
from Lighthill's equation and the Kirchhoff surface method. These
predictions are
in good agreement with the directly computed data. The Lighthill source
terms have
a large spatial distribution in the axial direction necessitating the introduction
of
a model to describe the source terms in the region downstream of the last
vortex
pairing. The axial non-compactness of the quadrupole sources must be adequately

treated in the prediction method.
Self-lubricated transport of bitumen froth
Authors: JOSEPH DANIEL D. , BAI RUNYAN , MATA CLARA , SURY KEN , GRANT CHRIS
Published: July 2002

Bitumen froth is produced from the oil sands of Athabasca using the Clark's Hot
Water Extraction process. When transported in a pipeline, water present in the froth is
released in regions of high shear, namely at the pipe wall. This results in a lubricating
layer of water that allows bitumen froth pumping at greatly reduced pressures
and hence the potential for savings in pumping energy consumption. Experiments
establishing the features of the self-lubrication phenomenon were carried out in a
25 mm diameter pipeloop at the University of Minnesota, and in a 0.6 m diameter
pilot pipeline at Syncrude, Canada. The pressure gradient of lubricated flows in
25 mm, 50 mm and 0.6 m diameter pipes closely follow the empirical law of Blasius
for turbulent pipe flow; the pressure gradient is proportional to the ratio of the 7/4th
power of the velocity to the 5/4th power of the pipe diameter, but the constant of
proportionality is about 10 to 20 times larger than that for water alone. We used
Reichardt's model for turbulent Couette flow with a friction velocity based on the
shear stress acting on the pipe wall due to the imposed pressure gradient to predict
the effective thickness of the lubricating layer of water. The agreement with direct
measurements is satisfactory. Mechanisms for self-lubrication are also considered.
Numerical and experimental investigations of
oblique boundary layer transition
Authors: BERLIN STELLAN , WIEGEL MARKUS , HENNINGSON DAN S.
Published: July 2002

A transition scenario initiated by two oblique waves is studied in an incompressible
boundary layer. Hot-wire measurements and flow visualizations from the first
boundary layer experiment on this scenario are reported. The experimental results are
compared with spatial direct numerical simulations and good qualitative agreement
is found. Also, quantitative agreement is found when the experimental device for
disturbance generation is closely modelled in the simulations and pressure gradient
effects taken into account. The oblique waves are found to interact nonlinearly to
force streamwise vortices. The vortices in turn produce growing streamwise streaks
by non-modal linear growth mechanisms. This has previously been observed in
channel flows and calculations of both compressible and incompressible boundary
layers. The flow structures observed at the late stage of oblique transition have
many similarities to the corresponding ones of K- and H-type transition, for which
two-dimensional Tollmien–Schlichting waves are the starting point. However, two-dimensional Tollmien–Schlichting waves are usually not initiated or observed in
oblique transition and consequently the similarities are due to the oblique waves and
streamwise streaks appearing in all three scenarios.
An experimental investigation of
a three-dimensional turbulent boundary layer in
an ‘S’-shaped duct
Authors: BRUNS J. M. , FERNHOLZ H. H. , MONKEWITZ P. A.
Published: July 2002

This paper describes the evolution of an incompressible turbulent boundary layer on
the flat wall of an ‘S’-shaped wind tunnel test section under the influence of changing
streamwise and spanwise pressure gradients. The unit Reynolds number based on the
mean velocity at the entrance of the test section was fixed to 106 m−1, resulting in Reynolds numbers Reδ2, based on the
streamwise momentum thickness and the local freestream velocity, between 3.9 and
11 × 103. The particular feature of the experiment
is the succession of two opposite changes of core flow direction which causes a sign
change of the spanwise pressure gradient accompanied by a reversal of the spanwise
velocity component near the wall, i.e. by the formation of so-called cross-over velocity
profiles. The aim of the study is to provide new insight into the development of the
mean and fluctuating flow field in three-dimensional pressure-driven boundary layers,
in particular of the turbulence structure of the near-wall and the cross-over region.

Mean velocities, Reynolds stresses and all triple correlations were measured with a
newly developed miniature triple-hot-wire probe and a near-wall hot-wire probe which
could be rotated and traversed through the test plate. Skin friction measurements
were mostly performed with a wall hot-wire probe. The data from single normal wires
extend over wall distances of y+ [gsim ] 3 (in wall units), while the triple-wire probe covers
the range y+ [gsim ] 30. The data show the behaviour of the mean flow angle near the
wall to vary all the way to the wall. Then, to interpret the response of the turbulence
to the pressure field, the relevant terms in the Reynolds stress transport equations are
evaluated. Finally, an attempt is made to assess the departure of the Reynolds stress
profiles from local equilibrium near the wall.
Experimental study of rivulet formation on an
inclined plate by fluorescent imaging
Authors: JOHNSON M. F. G. , SCHLUTER R. A. , MIKSIS M. J. , BANKOFF S. G.
Published: July 2002

The instability of a two-dimensional moving contact line is studied for a thin liquid film
flowing down an inclined plane, leading to the formation of rivulets. A fluorescent
imaging method was developed to facilitate accurate measurement of the spacing
between rivulets, tip velocity, three-dimensional shape and dynamic contact line.
A fluid circulation system produced steady films at constant volumetric flux, in
contrast to time-varying films at constant total volume, as in previous measurements.
Comparisons are made with the existing data for constant-volume films, and with
theoretical predictions for the wavelength of the rivulets formed at constant inlet flow
rate. Data were also obtained for rivulet shapes, tip speeds and contact angles as
functions of the angle of inclination of the plate and liquid Reynolds number.
Examination of hypotheses in
the Kolmogorov refined turbulence theory
through high-resolution simulations.
Part 2. Passive scalar field
Authors: WANG LIAN-PING , CHEN SHIYI , BRASSEUR JAMES G.
Published: July 2002

Using direct numerical simulations (DNS) and large-eddy simulations (LES) of velocity
and passive scalar in isotropic turbulence (up to 5123 grid points), we examine
directly and quantitatively the refined similarity hypotheses as applied to passive scalar
fields (RSHP) with Prandtl number of order one. Unlike previous experimental investigations,
exact energy and scalar dissipation rates were used and scaling exponents
were quantified as a function of local Reynolds number. We first demonstrate that
the forced DNS and LES scalar fields exhibit realistic inertial-range dynamics and
that the statistical characteristics compare well with other numerical, theoretical and
experimental studies. The Obukhov–Corrsin constant for the
k−5/3 scalar variance spectrum obtained from the
5123 mesh is 0.87±0.10. Various statistics indicated
that the scalar field is more intermittent than the velocity field. The joint probability
distribution of locally-averaged energy dissipation εr and scalar dissipation χr is
close to log-normal with a correlation coefficient of 0.25±0.01 between the logarithmic
dissipations in the inertial subrange. The intermittency parameter for scalar
dissipation is estimated to be in the range 0.43≈0.77, based on direct calculations
of the variance of lnχr. The scaling exponents of the conditional scalar increment
δrθ[mid ]
χr,εr
suggest a tendency to follow RSHP. Most significantly, the scaling exponent of
δrθ[mid ]
χr,εr
over εr was shown to be approximately −⅙ in the
inertial subrange, confirming a dynamical aspect of RSHP. In agreement with recent experimental
results (Zhu et al. 1995; Stolovitzky et al. 1995), the probability
distributions of the random variable
βs = δrθ[mid ]
χr,εr/
(χ1/2r
ε−⅙rr1/3) were found to be nearly Gaussian. However, contrary to the
experimental results, we find that the moments of βs are almost
identical to those for the velocity field found in Part 1 of this study
(Wang et al. 1996) and are
insensitive to Reynolds number, large-scale forcing, and subgrid modelling.
Topological fluid mechanics of stirring
Authors: BOYLAND PHILIP L. , AREF HASSAN , STREMLER MARK A.
Published: July 2002

A new approach to regular and chaotic fluid advection is presented that utilizes the
Thurston–Nielsen classification theorem. The prototypical two-dimensional problem
of stirring by a finite number of stirrers confined to a disk of fluid is considered. The
theory shows that for particular ‘stirring protocols’ a significant increase in complexity
of the stirred motion – known as topological chaos – occurs when three or more stirrers
are present and are moved about in certain ways. In this sense prior studies of chaotic
advection with at most two stirrers, that were, furthermore, usually fixed in place and
simply rotated about their axes, have been ‘too simple’. We set out the basic theory
without proofs and demonstrate the applicability of several topological concepts to
fluid stirring. A key role is played by the representation of a given stirring protocol
as a braid in a (2+1)-dimensional space–time made up of the flow plane and a time
axis perpendicular to it. A simple experiment in which a viscous liquid is stirred by
three stirrers has been conducted and is used to illustrate the theory.
On the dual nature of the ‘possessive’ marker in

Modern English
Authors: ZRIBI-HERTZ ANNE
Published: July 2002

This paper shows, after Watkins (1967) and Tremblay (1989, 1991),
that the

possessive phrase of This is John's does not necessarily

include an elliptical Possessee.

This ambiguity is argued to arise from the dual nature of the possessive
marker,

which may either be inflectional or derivational in Modern English. In
the

first case, it may

be analysed as a functional head, as proposed by Abney (1987) and Kayne
(1993,

1994); in the second case, it operates in the lexicon, deriving possessive
adjectives

which exhibit complementary morphological and semantic properties in adnominal

and predicate positions.
Towards an explanation of phonetic differentiation
in masculine and feminine personal names
Authors: HOUGH CAROLE
Published: July 2002

Recent research has identified characteristic differences between the phonetic
structures of names and of ordinary nouns, with particularly distinctive patterns
being exhibited by feminine personal names. No explanation has yet been found. This
paper suggests that the solution lies not in the English sound system, as has previously
been assumed, but in differences between the linguistic origins of the various types of
material.
Safe sects? dynamic religion and AIDS in South Africa
Authors: Garner Robert C.
Published: July 2002

The HIV/AIDS epidemic in South Africa is rapidly escalating, and its
demographic and social impact is beginning to be felt. Although the damage
to the macro-economy is projected to be slight, the consequences for affected
households will be dire, and social indicators such as life expectancy will
deteriorate dramatically. A large majority of South Africans are affiliated to
Christian Churches, but this has not prevented the types of sexual behaviour
that promote the epidemic. Based on research in a KwaZulu township, this
article presents evidence on the level of extra- and pre-marital sex (EPMS)
among members of different church types. It is argued that only Pentecostal
churches significantly reduce EPMS among members; and that they achieve
this by maintaining high levels of four crucial variables: indoctrination,
religious experience, exclusion and socialisation.
Kinetic theory of high-frequency and low-pressure atomic discharges
Authors: PEYRAUD-CUENCA N. , FAUCHER P.
Published: July 2002

This paper gives a complete kinetic theory of atomic discharges
whatever their
parameters. Very high-frequency discharges and high-pressure continuous
discharges were studied in an earlier paper by the same authors [J.
Plasma Phys. 54, 309 (1995)]; in the
present paper we study low-pressure continuous discharges
or high-frequency discharges whose parameters satisfy different conditions
and
therefore cannot be described by the earlier model. Analytical results
are applied
to a high-frequency argon discharge and to a low-pressure continuous argon
discharge. The results are in good agreement with the numerical results
of
Ferreira and co-workers.
Transport scaling and trapping
Authors: VLAD M. , REUSS J.-D. , SPINEANU F. , MISGUICH J. H.
Published: July 2002

It is shown that particle trapping plays an important role in the
appearance of
anomalous or strange diffusion in turbulent fields, mainly by inducing
a non-Gaussian
statistics of the stochastic displacements. Trapping processes are
responsible for the important deviation observed between the traditional
prediction of Bohm scaling for diffusion in low-frequency turbulence and
the
numerically checked prediction by Isichenko. Also, several theoretical
models
are proposed or reviewed.
Millimetre-wave second-harmonic generation in
an underdense magnetoplasma with a density ripple
Authors: PARASHAR J. , BHARUTHRAM R.
Published: July 2002

A high-power millimetre wave (ω1, k1) propagating through a
magnetized plasma at an angle to a density ripple (0, k0) produces density
perturbations (ω1, k1, k0). The density perturbations couple with the oscillatory
velocity at (ω1, k1) to produce a nonlinear
current at (2ω1, 2k1+k0) driving
second-harmonic electromagnetic radiation. The efficiency of the process is
sensitive to the angle between the density ripple and the millimetre wave.
Doàn thi Diêm's ‘Story of the Vân Cát Goddess’ as a Story of Emancipation
Authors: Dror Olga
Published: July 2002

Most of the stories we know about the Vietnamese goddess Liêu Hanh derive from Doàn thi Diêm's story Vân Cát Thân Nũ Truyên. This article analyses the story, arguing that in fact it is a piece of fiction which reflects the author's views, experiences and aspirations for greater freedom for women.
Factors influencing the density and morphometrics of the cup coral Caryophyllia smithii in Lough Hyne
Authors: Bell James J. , Turner John R.
Published: July 2002

Populations of Caryophyllia smithii were studied at three sites of differing sedimentation regime in Lough Hyne, Ireland. The height, length, width and density of individuals were measured along with the depth of accumulated sediment on the rock substratum at each site. Calyx size was largest at the site of least sedimentation and smallest at the site of most sedimentation. In contrast, height of individuals was greatest at the site of most sedimentation and smallest at the site of least sedimentation. The height of individuals was correlated with the level of surrounding sediment (Pearson's correlation 0.836 P<0.05). The uppermost limit of C. smithii corresponded with the downward limit of the infralittoral zone at each site; 15, 13, and 12 m at the low, mid and highly sedimented site respectively. Density averaged over depth was greatest (70 ind m−2) at the site of moderate sedimentation and lowest (13 ind m−2) at the site of least sedimentation. Density was also found to increase with depth at the sites of moderate and high sedimentation.
Factors maintaining topography-related mosaic of barnacle and mussel on a rocky shore
Authors: Chiba Susumu , Noda Takashi
Published: July 2002

Substratum heterogeneity on rocky shores can affect the distribution pattern of sessile epibenthic organisms. The rocky shore at Usujiri, southern Hokkaido, Japan, is composed of well-developed, columnar jointed dolerites. In this area, landscape is characterized by a mosaic of barnacle and mussels, where species composition in patches differs among typical topographic-classes, i.e. barnacles dominate on horizontal planes and vertical planes while mussels only inhabit in grooves. To determine the factors maintaining those distribution patterns, the recruitment of dominant sessile species in the typical topographic-classes with and without adults of barnacles and mussels were examined by field experiment. The results showed that the distribution pattern was determined by recruitment, and the recruitment pattern was strongly affected by rock-surface topography. Moreover, the presence of conspecific adults contributed to the maintenance of this topography-related mosaic by facilitating recruitment. These results show: (1) the presence of resource division for rocky topography among barnacles and mussels; and (2) that intraspecific positive interaction rather than interspecific competition may play important role in maintaining the topography-related mosaic of barnacle and mussels at Usujiri.
Effects of diel and seasonal cycles on the dive duration of the minke whale (Balaenoptera acutorostrata)
Authors: Stockin K.A. , Fairbairns R.S. , Parsons E.C.M. , Sims D.W.
Published: July 2002

Minke whale (Balaenoptera acutorostrata) surfacing intervals were recorded over a period of three years in the coastal waters of Mull, Coll and the Small Isles, in the north-west of Scotland. Significant differences in surfacing intervals were noted both throughout the day and throughout the year. Surfacing intervals were shortest at noon and in the months of June and July. Surfacing intervals were longest both mid-morning and mid-afternoon and during May and August. Differences in surfacing intervals were interpreted to be the result of ecological changes such as different foraging strategies. Consequently, the results of this study have an impact on the methodologies and designs of minke whale sightings surveys.
New type of hand-held corer for meiofaunal sampling and vertical profile investigation: a comparative study
Authors: Tita G. , Desrosiers G. , Vincx M.
Published: July 2002

A new hand-held corer for meiofaunal sampling and vertical profile investigation was developed. Its design and use prevents problems connected with core compression caused by the use of a plunger for core extrusion as generally applied in common coring techniques. This represents an advantage when meiofauna vertical profiles are investigated. A comparison between vertical profiles obtained from the newly developed corer and from commonly used corers shows that non-extrusive techniques significantly reduce sediment core compression.
Regional Development in Rural Malaysia and the ‘Tribal Question’
Authors: Ibrahim Zawawi
Published: July 2002

In the field of research and studies pertaining to Malaysian rural society, there has traditionally been a dominant emphasis, especially by local scholars, on the analysis of the indigenous Malay peasantry rather than on the equally indigenous ‘tribal’ minorities, i.e. the Orang Asli. This has also meant that the new theoretical directions and perspectives developed in the various interrelated fields (such as ‘the New Economic Anthropology’, ‘Peasant Studies’, and Political Economy, including the Neo-Marxist School of Development and Underdevelopment) have been applied with rigour only to those issues arising from ‘the peasant question’ in Malaysia. To date, no scholars have as yet seriously attempted to address ‘the agrarian question’ in the context of Malaysian society by also incorporating in their theoretical analysis the position of its ‘tribal’ minorities.
QUELQUES NOTES SUR ΠNIKTOΣ
Authors: PHILIP MAERTENS
Published: July 2002

Le mot πνικτóς utilisé en Ac 15.29 est l’adjectif verbal du verbe πνι´γω dont la signification de base est étouffer, suffoquer, étrangler. Il s’agit donc d’une façon de tuer soit un homme, soit un animal. Des quatre termes du Décret établis lors du Concile de Jérusalem, il est sans doute le terme le plus énigmatique et le plus important dans une tentative de compréhension du sens des restrictions. L’article ici présenté ne se veut pas une recherche sur la signification de l’ensemble du Décret mais est une proposition d’une autre lecture du mot πνικτóς. Cette lecture fait suite à une interrogation sur la position traditionnelle pour laquelle, dans le contexte du Concile, le terme πνικτóς signifie la viande d’un animal étouffé et qui n’a donc pas été complètement vidé de son sang.
Classification of plant trypanosomatids (Phytomonas spp.):
parity between random-primer DNA typing and multilocus enzyme electrophoresis
Authors: MULLER E. , GARGANI D. , BANULS A. L. , TIBAYRENC M. , DOLLET M.
Published: July 2002

The genetic polymorphism of 30 isolates of plant trypanosomatids
colloquially referred to as plant trypanosomes was
assayed by means of RAPD. The principle objectives of this study were to
assess the discriminative power of RAPD
analysis for studying plant trypanosomes and to determine whether the
results obtained were comparable with those from
a previous isoenzyme (MLEE) study. The principle groups of plant trypanosomes
identified previously by isoenzyme
analysis – intraphloemic trypanosomes, intralaticiferous trypanosomes
and trypanosomes isolated from fruits – were also
clearly separated by the RAPD technique. Moreover, the results showed a
fair
parity between MLEE and RAPD data
(coefficient of correlation = 0·84) and the two techniques
have comparable discriminative ability. Most of the separation
revealed by the two techniques between the clusters was associated with
major biological properties. However, the RAPD
technique gave a more coherent separation than MLEE because the
intraphloemic isolates, which were biologically similar
in terms of their specific localization in the sieve tubes of the plant,
were found to be in closer groups by the RAPD. For
both techniques, the existence of the main clusters was correlated with
the
existence of synapomorphic characters, which
could be used as powerful tools in taxonomy and epidemiology.
Human Toxocara infection of the central nervous system
and neurological disorders: a case-control study
Authors: MAGNAVAL J.-F. , GALINDO V. , GLICKMAN L. T. , CLANET M.
Published: July 2002

Infection with Toxocara canis is a common world-wide
human helminthiasis, which rarely elicits central nervous system
(CNS) impairment. A case-control study to investigate this discrepancy
was
carried out, in which the cases were 27 adult
neurological inpatients for whom a definite aetiological diagnosis was
lacking,
and for whom positive immunodiagnosis
of toxocariasis had been obtained, both in cerebrospinal fluid (CSF) and
in
serum. Two control groups were used. Controls
were adult inpatients with other neurological diseases who had no evidence
of
T. canis infection of the CNS. Multivariate
logistic regression analysis did not reveal any positive relation between
case status and clinical signs. A significant
association was observed between case status and an elevated CSF cell count.
Rural residence, ownership of dogs, and
dementia were shown to be risk factors for toxocaral infection of CNS.
These
results suggest that migration of T. canis
larvae in the human brain does not frequently induce a recognizable neurological
syndrome but is correlated with the
association of several risk factors including exposure to dogs, a status
possibly responsible for repeated low-dose infections.
In vitro stimulation of metacyclogenesis in Leishmania

braziliensis, L. donovani, L. major and L. mexicana
Authors: ZAKAI H. A. , CHANCE M. L. , BATES P. A.
Published: July 2002

Promastigotes of Leishmania braziliensis, L. donovani,

L. major and L. mexicana recently derived from tissue
amastigotes
were cultured in Schneider's Drosophila medium supplemented
with
20% (v/v) heat-inactivated foetal calf serum and 25 μg gentamicin

sulfate/ml at pH 5·5. These cultures produced more metacyclic

promastigotes in their stationary-phase
populations than others cultured at pH 7·0. Metacyclic promastigotes

possessed a short ([les ]8 μm) and narrow ([les ]1·5 μm)
cell body with a flagellum twice or more the length of the cell body.
Promastigotes from acidic cultures were more resistant
to complement-mediated lysis and more infective in vivo than
those grown at neutral pH. These results demonstrate that
induction of metacyclogenesis by acidic pH is a response conserved across

a variety of species of Leishmania.
Immunolocalization of the fatty acid-binding protein

Sj-FABPc within adult Schistosoma japonicum
Authors: GOBERT G. N. , STENZEL D. J. , JONES M. K. , McMANUS D. P.
Published: July 2002

This paper describes the first localization study of the

14·7 kDa fatty acid-binding protein in Schistosoma japonicum

(Sj-FABPc) using transmission electron microscopy. A polyclonal antibody

raised against recombinant Sj-FABPc was used

in combination with a colloidal gold marker to determine the distribution

of the protein within adult parasites. Sj-FABPc

was localized within lipid droplets below the subtegumental region of the

male parasite. Additionally, Sj-FABPc was

present in the vitelline droplets of the vitelline glands of female

parasites. There were no detectable levels of Sj-FABPc

on the surface or within the tegument of male or female parasites.

Possible functions of Sj-FABPc within S. japonicum

and the relevance of these immunolocalization findings in light of the

recent reports that the homologue Sm-FABPc is

an important anti-S. mansoni vaccine target molecule are also
discussed.
Blocked hepatic-stage parasites and decreased
susceptibility to Plasmodium berghei infections in
BALB/c mice
Authors: NGONSEU E. , CHATTERJEE S. , WERY M.
Published: July 2002

The BALB/c strain of mice is comparatively more resistant to
sporozoite infections of Plasmodium berghei than the C57BL6
strain. Infection with live sporozoites results in the formation of small
hepatic forms in the BALB/c liver that persist for
as long as 6 days. Upon infection with small numbers of sporozoites, some
of the parasites are destroyed in the liver
whereas the rest persist as blocked forms. When larger numbers of sporozoites
are injected the same process occurs but,
in addition, a fraction of the liver-stage parasites complete full development
and give rise to blood forms. Although blocked
liver forms persist until day 6 post-infection they actually develop to
only 24 h of maturity. The nature of these persistent
forms is similar to those obtained from irradiated sporozoite immunization.
There is a stronger cell proliferation to liver-stage antigens by spleen
lymphocytes of irradiated sporozoite-immunized BALB/c mice in comparison
to that of
immunized C57BL6 mice suggesting that a stronger priming to liver-stage
antigens, probably due to the presence of
blocked hepatic forms in the liver for a longer period of time (as compared
to C57BL6), occurs in the BALB/c mice. This
could be a reason for the long-lasting protective memory observed in BALB/c
mice.
Influence of parasitization by Trichinella spiralis on the

levels of heat shock proteins in rat liver and muscle
Authors: MARTINEZ J. , PEREZ SERRANO J. , BERNADINA W. E. , RODRIGUEZ-CAABEIRO F.
Published: July 2002

To examine levels of heat shock proteins (HSPs) in host responses
to helminth infection, rats were infected with Trichinella
spiralis. The kinetics of HSP25, HSP60, HSP70 and HSP90 production
in the liver and muscle of infected rats was
compared with that of non-infected controls. HSPs were detected using electrophoretic
analysis of fixed amounts of
proteins (0·02 mg) and then blotting and incubation of membranes
with polyclonal anti-HSP25 antibody, or monoclonal
antibody against HSP60, or HSP70 or HSP90. Quantitation of blotted separated
polypeptides reactive with the specific
anti-HSP antibodies was achieved using an image analyser. Enhancement of
HSP25 production was observed in the liver
of infected rats, whereas muscle from the same rats exhibited enhanced
production of HSP25 and HSP60 one day after
infection only. These data indicate that HSPs levels can be used successfully
to measure stress injury brought about by
helminth infection in organs and tissues of the host.
In vivo expression and distribution of dense granule
protein 7 (GRA7) in the exoenteric (tachyzoite,
bradyzoite) and enteric (coccidian) forms of Toxoplasma
gondii
Authors: FERGUSON D. J. P. , JACOBS D. , SAMAN E. , DUBREMETZ J-F. , WRIGHT S. E.
Published: July 2002

The in vivo expression and distribution of the dense granule protein GRA7 was examined in both the exoenteric (tachyzoite
and bradyzoite) and enteric (coccidian) forms of Toxoplasma gondii by immunocytochemistry. There was strong staining
of GRA7 in granules within all the infectious stages (tachyzoite, bradyzoite, merozoite and sporozoite). During tachyzoite
development, GRA7 was secreted and was associated with the parasitophorous vacuole. In contrast, although there was
staining of granules within the bradyzoites of more mature cysts, there appeared to be little staining of the tissue cyst wall
or host cell. The apparent stage-specific variation in secretion of GRA7 between tachyzoites and bradyzoites was confirmed
by double labelling using stage-specific markers (SAG1 and BAG1). In the enteric forms in the cat gut there was strong
labelling of the PV containing early asexual and sexual stages and staining of a few granules in the apical cytoplasm of the
merozoite. The positive enteric staining pattern differentiates GRA7 from the other GRA proteins (GRA1–6) which were
absent in the merozoites and enteric stages. The staining pattern of GRA7 with strong staining during tachyzoite and
enteric development and reduced staining in the tissue cysts is similar to that seen for NTPases. The function of GRA7
is unknown but it is unique among the dense granule proteins in being expressed in all the infectious forms of T. gondii
which would point to a basic role in the vacuolar adaptations required for active parasite development.
Phylogenetic relationships among species of Contracaecum
Railliet & Henry, 1912 and Phocascaris Høst, 1932
(Nematoda[ratio ]Ascaridoidea) based on nuclear rDNA sequence data
Authors: NADLER S. A. , D'AMELIO S. , FAGERHOLM H.-P. , BERLAND B. , PAGGI L.
Published: July 2002

Nuclear-encoded large-subunit ribosomal DNA sequences were used to infer a phylogenetic hypothesis for 17 taxa (16
nominal species) of the genera Contracaecum and Phocascaris. Phylogenetic trees based on these data have been used to
assess the validity of the taxonomic distinction between these genera, which was based on the presence or absence of
certain structural features, rather than on explicit hypotheses of evolutionary history. Phylogenetic hypotheses based on
parsimony, likelihood, and neighbor-joining analyses of these sequence data strongly support the hypothesis that species
of Phocascaris are nested within the clade of Contracaecum species hosted by phocid seals, and are more closely related to
species of the Contracaecum osculatum complex than to other Contracaecum species. Alternative tree topologies representing
Phocascaris as not nested within the C. osculatum complex were significantly worse interpretations of these sequence data.
Phylogenetic analysis also provides strong support for the monophyly of all taxa (Contracaecum and Phocascaris) from
phocid seals, which is consistent with Berland's (1964) proposal that such species form a natural group; however, his
proposal to recognize all species in phocid seals as Phocascaris, with all species from birds as Contracaecum would result
in a paraphyletic Contracaecum, according to the molecular phylogenetic hypothesis.
Moral Dilemmas are not a Local Issue
Authors: Baltzly Dirk
Published: July 2002

W. A. Hart argues that Martha Nussbaum does not make a convincing case there are genuine moral dilemmas to be found in Aeschylus' Agamemnon. Hart claims that the impossibility of moral dilemmas flows from the Kantian principle that ‘ought implies can’. A certain understanding of OIC does rule out the possibility of moral dilemmas. However, this particular formulation of the OIC principle does not fit well with the eudaimonist framework common to ancient moral philosophy. It emerges that there are trade offs to be made between the ancients' views on the point of moral evaluation and ours. Thus the possibility of moral dilemmas is an issue that in inextricably enmeshed in larger issues in moral philosophy.
Courses of Action or the Uncatchableness of Mental Acts
Authors: Ryle Gilbert
Published: July 2002

We falter and stammer when trying to describe our own mental acts. Many mental acts, including thinking, are what the author calls ‘chain-undertakings’, that is, courses of action with some over-arching purpose governing the moment-by-moment sub-acts of which we are introspectively aware. Hence the intermittency and sporadicness of the passage of mental activity which constitutes thinking about something.
Does Science Persecute Women? The case of the 16th–17th Century Witch-hunts
Authors: GREEN KAREN , BIGELOW JOHN
Published: July 2002

I. Logic, rationality and ideology

Herbert Marcuse once claimed that the ‘“rational” is a mode of thought and action which is geared to reduce ignorance, destruction, brutality, and oppression.’ He echoed a widespread folk belief that a world in which people were rational would be a better world. This could be taken as an optimistic empirical conjecture: if people were more rational then probably the world would be a better place (a trust that ‘virtue will be rewarded’, so to speak). However, it is also worth considering a stronger hypothesis: that if something did not reduce ignorance, destruction, brutality, and oppression then it would not constitute rationality. On this view there is no mere correlation between rationality and a propensity toward reduction in ignorance and the rest, it is the propensity to reduce ignorance, destruction, brutality and oppression which in part constitutes rationality. Call this a broad conception of rationality, because it expands beyond the epistemic goal of reducing ignorance, and reaches out to moral concerns like oppression.