bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of selection for development rate on reproductive
onset in female mice
Authors: ERNST C. A. , CRENSHAW P. D. , ATCHLEY W. R.
Published: July 2002

This research reports analyses of correlated response in reproductive onset in ICR mice after 23
generations of restricted index selection for divergent body weight gain, early (birth–10 days) or
later (28–56 days) in life. Long-term selection altered growth trajectories and 56 day body weight
of individuals under different selection regimes in this study. Mice in lines under early selection
have the same percentage mature weight at vaginal opening as controls (63%). Vaginal opening is
delayed in mice selected for slow early growth, which take longer to reach what appears to be a
weight threshold. In contrast, individuals in lines selected for later slow growth undergo vaginal
opening at the same age as controls, but at a lower weight and increased percentage mature
weight. Pre-compensation or ‘counter-balance growth’ is observed in these lines, with mice selected
for late enhanced growth reaching 52% of mature weight at vaginal opening while mice with late
slow growth attain 71% of mature weight prior to vaginal opening. Only 42% of mice with late
slow growth attain first oestrus by 56 days. We speculate this is a function of growth rate and
fat/lean ratio. Mice with early slow growth show compensatory growth, reaching first oestrus at a
similar time to controls. We conclude that selection for growth rate has asymmetrically affected
reproductive onset, with lines selected for suppressed gains experiencing delays in the reproductive
onset traits measured.
Thrusting in the lower crust: evidence from the Oygarden
Islands, Kemp Land, East Antarctica
Authors: KELLY N. M. , CLARKE G. L. , CARSON C. J. , WHITE R. W.
Published: July 2002

Layered orthogneisses of the Oygarden Islands preserve evidence for four high-grade deformation
events (D1 to D4). Archaean D1 and D2 structures are only patchily preserved due to extensive
recrystallization during D3 and D4, which represent effects of the c. 1000 Ma Rayner Structural
Episode. Ductile thrusting at middle to lower crustal levels occurred during D3, which is separated into
two mutually cross-cutting phases based on structural geometry; the two phases represent changes in
finite strain that developed during progressive deformation. East-directed transport during D3a developed
subhorizontal thrusts that contain co-axial, east-trending F3a folds and L3a lineations. Buckling
as a consequence of constriction in thrust duplexes developed upright F3b folds coaxial to F3a folds,
and steeply south-dipping D3b shear zones. Garnet–clinopyroxene- and garnet–orthopyroxene-bearing
assemblages in mafic lithologies, and garnet–sillimanite-bearing assemblages in pelitic lithologies
reflect D3 conditions of P=9 kbar and T=800–850 °C. The well-exposed D3 duplex structures indicate
that shortening of the lower crust may be accommodated by extensive strain partitioning to
develop contemporary kilometre-scale thrust stacking and ductile flow.
Lava flow growth inferred from morphometric parameters: a case

study of Citlaltépetl volcano, Mexico
Authors: CARRASCO-NÚÑEZ GERARDO
Published: July 2002

Recent (Quaternary) lava fields, such as those of

Citlaltépetl (Pico de Orizaba) volcano in Mexico, are

excellent places to obtain precise measurements of flow-field

dimensions that can be used to estimate volume, eruption duration and

effusion rates. The relationship between these parameters and the

influence of some other interrelated features such as lava

composition, superficial structures and lava type are important tools

that can help to infer conditions when the lavas were active and thus

improve understanding of how flow fields grow. The Holocene lavas of

Citlaltépetl volcano are homogeneous in composition (dacites)

and are generally blocky with well-developed levees. The eruption

duration obtained for the Citlaltépetl lavas by a method

proposed by C. Kilburn and R. Lopes presents a good correlation with

the different lava types morphologically classified here. Results

from that method compare favourably with the inferred effusion rates

estimated by an empirical cooling method (Graetz). The lavas show

different behaviour, mainly controlled by fluctuations in the

effusion rate that promote changes from single- to multiple-flow

style. The maximum distance achieved by a flow is directly

proportional to the effusion rate in Citlaltépetl lavas, but

it is always lower for multiple flows, independent of the volume of

erupted lava. Observations of Citlaltépetl lavas can be used

to understand how lava flow growth occurs on other

volcanoes.
Simultaneous use of thermal indicators to analyse the transition
from diagenesis to metamorphism: an example from the Variscan
Belt of northwest Spain
Authors: GARCIA-LOPEZ SUSANA , BRIME COVADONGA , BASTIDA FERNANDO , SARMIENTO GRACIELA N.
Published: July 2002

The transition from diagenesis to very low-grade metamorphism has been
characterized by conodont
colour alteration index (CAI), illite crystallinity (IC), clay-mineral assemblages
and rock fabric in a
transect (Cape Peñas–Cape Torres) located in the Cantabrian Zone
(northwest Spain). IC values show a
northwest to southeast change from epizonal to diagenetic values. CAI values
show a general congruence
for low- and high-grade areas. This correlation indicates that CAI values for
the epizone are >5.5, the
anchizone 5.5≥CAI>4, and the diagenetic zone ≤4. Cleavage develops in
incompetent rocks with CAI
values greater than 3, mainly by pressure solution. Temperature increases
towards the inner parts of the orogen
(towards the northwest) and is considered to be related to the tectonic
superposition caused by thrusting
and folding. A gradient of 35°C/km is inferred for the transect. In the
southeastern sector of the section there
are several thermal anomalies that are attributed to the presence of
epithermal fluids.
A terminal Cretaceous giant pterosaur from the French Pyrenees
Authors: BUFFETAUT ERIC , LAURENT YVES , LE LOEUFF JEAN , BILOTTE MICHEL
Published: July 2002

A very large pterosaur cervical vertebra is described from the
Upper Maastrichtian deposits of Mérigon, in the foothills of the
French Pyrenees. It resembles the vertebrae of Quetzalcoatlus,
from the Maastrichtian of Texas, more than those of
Arambourgiania, from the Maastrichtian of Jordan. The estimated
wing span of the Mérigon pterosaur is close to 9 m,
which makes it one of the largest known flying creatures. Giant
pterosaurs still had a wide geographical distribution at the end
of Maastrichtian time, which is not suggestive of a declining
group, although it is difficult to obtain an accurate estimate of
taxonomic diversity of terminal Cretaceous pterosaurs on the
basis of available data.
A new pterodactyloid pterosaur from the Kimmeridgian of the
Cap de la Hève (Normandy, France)
Authors: BUFFETAUT ERIC , LEPAGE JEAN-JACQUES , LEPAGE GILLES
Published: July 2002

A pterosaur specimen, consisting of the associated anterior
portions of upper and lower jaws, is reported from the
upper Kimmeridgian Argiles d'Octeville, in the cliffs of the
Cap de la Hève, near Le Havre (France). It is described as a
new taxon, Normannognathus wellnhoferi, and referred to the
Germanodactylidae. Normannognathus wellnhoferi is distinguished

by the association of jaws which bear teeth up to their
anterior tip and a tall sagittal crest, formed by the premaxillae,
which begins anterior to the nasopreorbital fenestra, has a
concave anterior edge, and is much higher than the maxilla at
that level. The Dsungaripterus-like crest and the slightly
upturned upper jaw support the idea of a close relationship
between the Germanodactylidae and Dsungaripteridae.
Carbonate depositional environments in the late Wenlock of
England and Wales
Authors: RATCLIFFE K. T. , THOMAS A. T.
Published: July 2002

Based on outcrop studies and borehole data, six bedded lithofacies
and two reef types are
recognized within the Much Wenlock Limestone Formation of the English Midlands
and Welsh
Borderland. The lithofacies are interpreted to represent a series of carbonate
shelf environments
extending from below storm wave-base to well above fair weather wave-base.
In common with many
other shallow marine carbonate depositional systems, the principal controls
on lithofacies development
were hydrodynamic energy, the supply of fine clastic sediment, and patterns
of colonization of
the sea floor by organisms. Reef distribution was probably controlled by
the nature of the substrate,
water circulation, and rate of siliciclastic sedimentation. A depositional
model is proposed which
incorporates biostratigraphical evidence suggesting that the formation
youngs to the west on the
northern part of the shelf. Deposition of the Much Wenlock Limestone Formation
there began in the
West Midlands, where 12 m of microbial limestone were lain down in a mid-shelf
setting during a local
regression. The remainder of the shelf was dominated by low energy siliciclastic
deposition at that
time. The West Midlands then returned to somewhat deeper water, lower energy
deposition, the resulting
impure calcareous muds becoming diagenetically changed into the nodular
limestone lithofacies.
That lithofacies is commonly overlain successively by the interbedded limestone
and silty mudstone
lithofacies, and then the crinoidal grainstone lithofacies. This vertical
lithofacies sequence is uniform
over the entire northern part of the shelf, reflecting a gradual decrease
in water depth. The crinoidal
grainstone lithofacies was deposited as a wave-influenced carbonate sandbody
which prograded from
east to west. Lithofacies sequences on the southern shelf are laterally
impersistent, probably due to
greater tectonic instability and topographical variablity.
Self-organization origin of wood-grained chert, Portland
Limestone Formation (Upper Jurassic), southern England
Authors: MALIVA R. G. , DICKSON J. A. D. , SCHIAVON N. , FALLICK A. E.
Published: July 2002

Wood-grained chert is an unusual type of banded nodular chert that is characterized by
alternating thin dark-coloured bands and thicker light-coloured bands, which give the chert a texture
reminiscent of the growth rings of wood. The wood-grained texture found in some chert nodules in the
Portland Limestone Formation of southern England is the result of variations in the concentration of
calcite inclusions within the chert. Light-coloured bands contain more abundant calcite inclusions
than adjoining darker coloured chert bands. The Portland Limestone wood-grained cherts formed by
the late diagenetic replacement of a highly compacted carbonate sand, in which abundant siliceous
sponge spicules were the silica source. Oxygen and hydrogen isotope data
(δ18O=27.0 to 29.3‰;
δ18O=−71 to −91‰ V-SMOW), indicate that either
chert formation or, more likely, the opal-CT to
quartz transformation, occurred in meteoric or mixed marine and meteoric pore waters at temperatures
in the range of 20–60°C. The wood-grained texture likely formed by a self-organization process.
A feedback mechanism is proposed for the origin of the texture in which calcium and carbonate ions
released during the replacement of the host limestone resulted in calcite supersaturation along the
boundaries of growing chert nodule. Calcite inclusion-rich chert bands formed within the calcite
supersaturated zone and inclusion-poor bands formed outside of the calcite-supersaturated zone.
Wood-grained chert provides another example of how the coupling of reaction and transport can produce
repetitive patterns in otherwise unordered sediments or rock.
Estimating the detachment depth in cross sections
involving detachment folds
Authors: BULNES MAYTE , POBLET JOSEP
Published: July 2002

This paper evaluates four different methods that have been proposed for the estimation of
the detachment depth beneath detachment folds. Guidelines are presented in order to use the most
suitable method in a particular region deformed by detachment folds. These guidelines are constructed
considering the assumptions of each method, the influence of different parameters on the estimation
of the detachment depth (folding mechanisms, cross-sectional area variations, position and orientation
of the regional datum, number of stratigraphic horizons, bed length and thickness, dip and position
of the bounding lines, initial thickness of the ductile unit, single anticlines or fold trains) and the
available data (ductile unit thickness, regional datum, detachment depth). Moreover, a new, simple
method based on two previous methods is presented. The advantages of this new method are that the
calculations are extremely simple and it uses information from more than one stratigraphic horizon;
therefore, it does not depend strongly on the accuracy of the data at one level. The precision of the
proposed methods is tested by their application to a number of natural and experimental single anticlines
and fold trains. It appears that better predictions are obtained when analysing a complete
detachment fold train than when dealing with a single detachment anticline. The reason might be that
ductile material flow beneath the folds along the cross-sectional plane is taken into account when dealing
with a long-enough cross section. We also suggest some hypotheses concerning what the shape and
dimensions of the detachment folds indicate about the detachment depth in those cases where insufficient
data are available to apply the methods proposed.
Ordovician and Silurian stratigraphy and trilobites,
Taurus Mountains near Kemer, southwestern Turkey
Authors: DEAN W. T. , UYENO T. T. , RICKARDS R. B.
Published: July 2002

Lower Palaeozoic outcrops near Kemer comprise only Ordovician and Silurian strata in the
Upper Antalya Nappes, and are described in detail for the first time. The oldest rocks, Seydişehir
Formation (lower Arenig), resemble those of the central Taurides. A disconformity is probable, though
unexposed, below the succeeding Şort Tepe Formation (Ashgill), a unit seen elsewhere only in south central
and southeastern Turkey; sparse trilobites include Cyclopyge, Cyphoniscus, Panderia,
Symphysops, Ulugtella, and one new species Placoparia
(Hawleia) marcouxi. Silurian rocks (Sapandere Formation)
differ from those further east in the Taurides, and are of Llandovery (Telychian), Wenlock and ?Ludlow
age, based on conodonts, graptolites and trilobites (Cerauroides,
Otarion (Aulacopleura), Sphaerexochus)
the affinities of which lie with the Carnic Alps and western Europe. The Sapandere Formation is unconformably
overlain by red sandstones at the base of the Armutlugözlek Formation (Devonian).
ENGLAND, THE DUTCH REPUBLIC, AND EUROPE IN THE SEVENTEENTH CENTURY
Authors: ISRAEL JONATHAN
Published: July 2002

The Anglo-Dutch wars of the seventeenth-century.
By J. R. Jones. London: Longman, 1996.
Pp. 242. ISBN 0-582-05631-4. £42.00.

Oliver Cromwell. By Peter Gaunt. Oxford: Blackwell, 1996. Pp. 263.
ISBN 0-631-18356-6. £25.00.

Cromwellian foreign policy. By Timothy Venning. London and New
York: St Martin's Press and Macmillan, 1995. Pp. 324.
ISBN 0-333-63388-1. £47.50.

Protestantism and patriotism: ideologies and the making of
English foreign policy, 1650–1668. By
Steven C. A. Pincus. Cambridge: Cambridge University Press, 1996. Pp. 512. ISBN
0-521-43487-4. £45.00.

William III and the godly revolution. By Tony Claydon.
Cambridge: Cambridge University
Press, 1996. Pp. 288. ISBN 0-521-47329-2. £35.00.

A miracle mirrored: the Dutch republic in European perspective.
Edited by Karel Davids and
Jan Lucassen. Cambridge: Cambridge University Press, 1996. Pp. 559.
ISBN 0-521-46247-9. £55.00.
Effect of temperature on alkane extraction from faeces
and herbage
Authors: OLIVÁN M. , OSORO K.
Published: July 2002

The solvent extraction of alkanes from faeces and herbage samples at two different temperatures
(cold: 15–25°C and hot: 65°C) was studied in four samples of different matrix types (cattle faeces,
sheep faeces, hill grass and heather), in two experiments performed at Villaviciosa, Asturias, Spain
in 1994. Two internal standards (IS) of different chain length (C22 and C34) were used to estimate
alkane concentrations. Significant differences were detected in alkane extraction derived from
temperature of extraction, IS and sample matrix. At the cold temperature, long-chain alkane
extraction was not complete, resulting in errors in the estimation of alkane concentration when a
long-chain alkane (C34) was used as the only internal standard. However, under hot extraction, long-
chain alkanes were completely extracted by the heptane, although estimates made with C22 or C34 as
IS were not identical. These results suggest that it would be appropriate to use two internal standards
with short and long carbon chain, such as C22 and C34, in routine analyses to establish the
completeness of alkane extraction, even under hot conditions, by calculating the relative ratio of both
IS in extracts compared to the original C22[ratio ]C34 ratio added to the samples. Any increase or decrease
in expected peak areas could be adjusted for all the alkanes in the extracts, and the accuracy of alkane
concentration measurements (and therefore the reliability of estimates of intake and especially of diet
selection) would be improved.
Outside the Panel – Race in America's Popular Imagination:

Comic Strips Before and After World War II
Authors: LENTHALL BRUCE
Published: July 2002

In the wake of World War II, the unofficial cartoonist laureate
of the war,
Bill Mauldin, turned the focus of his comic art to life within America's

borders. In a 1946 panel, he portrayed two men talking in the shadow of

the United States Capitol building. The listener was clearly a slick senator;

the speaker looked to be a well-groomed tramp. His question no doubt
left the senator fumbling for an answer: “Do you mean your American

Way or my American Way, Senator?”

Mauldin did not provide us with the senator's response, but it
hardly
matters. The tramp's question all but answers itself. The supposed
post-war
consensus, the shared American Way, had not been achieved by
unanimous consent, the tramp was suggesting, but by leaving out those
who did not fit into it. The popular imagination of America might have

attained a single, clean vision of the nation, but only by cropping out

anything that could blur the picture. The imagined American Way would
not admit it, but there were others trying to climb into the frame.
Development of a medium simulating Emmental juice for
propionibacteria growth
Authors: SALVAT-BRUNAUD DELPHINE , THIERRY ANNE , MAUBOIS JEAN-LOUIS
Published: July 2002

Our aim was to develop an Emmental juice-like medium (EJLM) for
the
growth of propionibacteria. Cheese juices were extracted by pressing three
different
Emmental cheeses before entering the warm room (i.e. before propionic fermentation)

and their composition was determined. They contained (g/kg) lactate

34·6–36·9,
protein 23·8–29·6, NaCl 15–23, Ca
5·9–7·3 and no residual sugar, and had a pH of 5·4.

In order to simulate this composition, EJLM was constituted from the microfiltrate

of a milk, enriched in native casein and fermented by a
Lactobacillus helveticus strain until lactose exhaustion.
PO43−, K+,
Mg2+, Ca2+ and Cl−
were added to reach a mineral
balance and an ionic strength close to those of juice. The main difference
was the
nitrogen content: that of juice was ∼3·5 times that of EJLM.

Four Propionibacterium freudenreichii strains grew with similar
growth
rates in EJLM and in juice at 24°C in anaerobiosis and reached
>3×109 cfu/ml. Using EJLM, Prop.
freudenreichii TL 173 grew at pH 5·4 or 6·0, at 24 or

30°C, in semi-anaerobiosis (static
culture) or anaerobiosis (CO2 atmosphere), showing a
synergic inhibition of growth at
low pH and temperature and in semi-anaerobiosis. EJLM provided a way to
study
propionibacteria in an environment similar to that in Emmental cheese.
Parish-Church Cathedrals, 1836–1931: Some Problems and
their Solution
Authors: MORRISH P. S.
Published: July 2002

Traditionally scholars distinguish English Anglican cathedrals
of
‘old’ foundation and those of ‘new’, but since
Henry VIII a further
category has arisen comprising those established in the nineteenth
and early twentieth centuries to serve newly created dioceses. These are

often referred to as parish-church cathedrals because they mostly
remained parish churches even after their elevation. Their new status
raised various architectual and organisational problems, and this essay

concentrates on the latter, illustrating them with select examples. These

problems deserve examination because there is little recent literature
on
them and some passing references may tend to mislead.

Two events define the period. In 1836 the first modern parish-church

cathedral was created at Ripon. In 1931 the Cathedrals Measure
provided for revision of all cathedral statutes within general guidelines,

the outcome of a commission of enquiry which Church Assembly had
launched in 1924 and which had reported in 1927. Moreover by 1931,
albeit then unperceived, an era had ended in another respect because
after a surge of creations in the 1920s, no more new bishoprics have been

erected in England by the Anglican Church (despite various plans),
though some territorial adjustments have been made between dioceses,
notably the transfer of Croydon from Canterbury to Southwark.
Throughout much of this period popular odium surrounded cathedral
establishments, a residue from radical attack in the 1830s and 1840s upon

all ecclesiastical corporations whose wealth, admittedly often maladministered,

critics had hoped to appropriate to other uses, whose
neglect of duties had become scandalous, and whose quirky and outmoded

ways Trollope gently satirised in his Barchester novels. The period saw
a
piecemeal and relatively unco-ordinated response to the problems which

creation of these cathedrals involved, and that Church Assembly
commission explicitly deplored the ‘anomalous and confused’
situation
which had arisen.
The effect of air swirl profile on the instability of a viscous liquid jet
Authors: LIAO Y. , JENG S. M. , JOG M. A. , BENJAMIN M. A.
Published: July 2002

A temporal linear stability analysis has been carried out to predict the instability
of a viscous liquid jet surrounded by a swirling air stream with three-dimensional
disturbances. The effects of flow conditions and fluid properties on the instability of
the liquid jet are investigated via a parametric study by varying axial Weber number
axial velocity ratio of the gas to liquid phase, swirl Weber numbers, density ratio
and the Ohnesorge number. It is observed that the relative axial velocity between the
liquid and gas phases promotes the interfacial instability. As the axial Weber number
increases, the growth rates of unstable waves, the most unstable wavenumber and
the unstable range of wavenumbers increase. Meanwhile, the increasing importance
of helical modes compared to the axisymmetric mode switches the breakup regime
from the Rayleigh regime to the first wind-induced regime and on to the second
wind-induced regime. The predicted range of wavenumbers in which the first helical
mode has higher growth rates than the axisymmetric mode agrees very well with
experimental data. Results show that the destabilizing effects of the density ratio
and the axial Weber number are nearly the same. Liquid viscosity inhibits the
disintegration process of the liquid jet by reducing the growth rate of disturbances
and by shifting the most unstable wavenumber to a lower value. Moreover, it damps
higher helical modes more significantly than the axisymmetric mode. Air swirl has
a stabilizing effect on the liquid jet. As air swirl strength increases, the growth rates
of helical modes are reduced more significantly than that of the axisymmetric mode.
The air swirl profile is found to have a significant effect on the instability of the liquid
jet. The global, as well as local, effects of the swirl profile are examined in detail.
Direct numerical simulations of the Crow instability and subsequent vortex reconnection in a stratified fluid
Authors: GARTEN J. F. , WERNE J. , FRITTS D. C. , ARENDT S.
Published: July 2002

The evolution of a vertically propagating three-dimensional vortex pair in ambient
stratification is studied with a three-dimensional numerical model. We consider a
range of Reynolds (Re) and Froude (Fr) numbers, and initialize the vortex pair
in a configuration that promotes growth of the Crow instability (Crow 1970). The
growth rate of the instability is Re dependent, and we present a method for extending
Crow's model to predict this dependence. We also find that relatively strong ambient
stratification (Fr [les ] 2) further alters the growth of the instability via advection by
baroclinically produced vorticity. For all of our cases with Fr [ges ] 1 (including our
unstratified cases where Fr → ∞), the instability leads to vortex reconnection and
formation of a vortex ring. A larger Re delays the commencement of the reconnection,
but it proceeds more rapidly once it does commence. We compute a reconnection time
scale (tR), and find that tR ∼ 1/Re,
in agreement with a model formulated by Shelley
et al. (1993). We also discuss a deformative/diffusive effect (related to yet distinct from
the curvature reversal effect discussed by Melander & Hussain 1989) which prevents
complete reconnection. Ambient stratification (in the range Fr [ges ] 1) accelerates the
reconnection and reduces tR by an amount roughly proportional to 1/Fr. For some
Fr, stratification effects overwhelm the deformative effect, and complete reconnection
results.
Inertial waves in a rotating spherical shell: attractors and asymptotic spectrum
Authors: RIEUTORD M. , GEORGEOT B. , VALDETTARO L.
Published: July 2002

We investigate the asymptotic properties of inertial modes confined in a spherical
shell when viscosity tends to zero. We first consider the mapping made by the
characteristics of the hyperbolic equation (Poincaré's equation) satisfied by inviscid
solutions. Characteristics are straight lines in a meridional section of the shell, and the
mapping shows that, generically, these lines converge towards a periodic orbit which
acts like an attractor (the associated Lyapunov exponent is always negative or zero).
We show that these attractors exist in bands of frequencies the size of which decreases
with the number of reflection points of the attractor. At the bounding frequencies the
associated Lyapunov exponent is generically either zero or minus infinity. We further
show that for a given frequency the number of coexisting attractors is finite.

We then examine the relation between this characteristic path and eigensolutions of
the inviscid problem and show that in a purely two-dimensional problem, convergence
towards an attractor means that the associated velocity field is not square-integrable.
We give arguments which generalize this result to three dimensions. Then, using
a sphere immersed in a fluid filling the whole space, we study the critical latitude
singularity and show that the velocity field diverges as 1/√d, d being the distance to
the characteristic grazing the inner sphere.

We then consider the viscous problem and show how viscosity transforms singularities
into internal shear layers which in general reveal an attractor expected at the
eigenfrequency of the mode. Investigating the structure of these shear layers, we find
that they are nested layers, the thinnest and most internal layer scaling with E1/3, E
being the Ekman number; for this latter layer, we give its analytical form and show
its similarity to vertical 1/3-shear layers of steady flows. Using an inertial wave packet
travelling around an attractor, we give a lower bound on the thickness of shear layers
and show how eigenfrequencies can be computed in principle. Finally, we show that
as viscosity decreases, eigenfrequencies tend towards a set of values which is not dense
in [0, 2Ω], contrary to the case of the full sphere (Ω is the angular velocity of the
system).

Hence, our geometrical approach opens the possibility of describing the eigenmodes
and eigenvalues for astrophysical/geophysical Ekman numbers
(10−10–10−20), which are out of reach numerically,
and this for a wide class of containers.
Deformation of a two-dimensional drop at non-zero Reynolds number in time-periodic extensional flows: numerical simulation
Authors: SARKAR KAUSIK , SCHOWALTER WILLIAM R.
Published: July 2002

The shape of a two-dimensional viscous drop deforming in several time-dependent
flow fields, including that due to a potential vortex, has been studied. Vortex flow
was approximated by linearizing the induced velocity field at the drop centre, giving
rise to an extensional flow with rotating axes of stretching. A generalization of the
potential vortex, a flow we have called rotating extensional flow, occurs when the
frequency of revolution of the flow is varied independently of the shear rate. Drops
subjected to this forcing flow exhibit an interesting resonance phenomenon. Finally
we have studied drop deformation in an oscillatory extensional flow.

Calculations were performed at small but non-zero Reynolds numbers using an
ADI front-tracking/finite difference method. We investigate the effects of interfacial
tension, periodicity, viscosity ratio, and Reynolds number on the drop dynamics.
The simulation reveals interesting behaviour for steady stretching flows, as well as
time-dependent flows. For a steady extensional flow, the drop deformation is found to
be non-monotonic with time in its approach to an equilibrium value. At sufficiently
high Reynolds numbers, the drop experiences multiple growth–collapse cycles, with
possible axes reversal, before reaching a final shape. For a vortex flow, the long-time deformation reaches a steady value, and the drop attains a revolving steady
elliptic shape. For rotating extensional flows as well as oscillatory extensional flows,
the maximum value of deformation displays resonance with variation in parameters,
first increasing and then decreasing with increasing interfacial tension or forcing
frequency. A simple ODE model with proper forcing is offered to explain the observed
phenomena.
Near-contact motion of surfactant-covered spherical drops
Authors: CRISTINI VITTORIO , BŁAWZDZIEWICZ J. , LOEWENBERG MICHAEL
Published: July 2002

A lubrication analysis is presented for the near-contact axisymmetric
motion of
spherical drops covered with an insoluble non-diffusing surfactant. Detailed
results
are presented for the surfactant distribution, the interfacial velocity,
and the gap width
between the drop surfaces. The effect of surfactant is characterized by
a dimensionless
force parameter: the external force normalized by Marangoni stresses. Critical
values
of the force parameter have been established for drop coalescence and separation.

Surfactant-covered drops are stable to rapid coalescence for external forces
less than
4πkTac0, where c0 is the
surfactant concentration at the edge of the near-contact
region and a is the reduced drop radius.

For subcritical forces, the behaviour of surfactant-covered drops is
described by two
time scales: a fast time scale characteristic of near-contact motion between
drops with
clean interfaces and a slow time scale associated with rigid particles.
The surfactant
distribution evolves on the short time scale until Marangoni stresses approximately

balance the external force. Supercritical values of the external force
cannot be balanced;
coalescence and separation occur on the fast time scale. The coalescence
time
normalized by the result for drops with clean interfaces is independent
of the viscosity
ratio and initial gap width.

Under subcritical force conditions, a universal long-time behaviour
is attained on
the slow time scale. At long times, the surfactant distribution scales
with the
near-contact region and the surface velocity is directed inward which impedes
the drop
approach and accelerates their separation compared to rigid particles.
For drops
pressed together with a sufficiently large subcritical force, a shrinking
surfactant-free
clean spot forms.

Surfactant-covered drops exhibit an elastic response to unsteady external
forces
because of energy stored in the surfactant distribution.
Turbulent shear-layer mixing at high Reynolds
numbers: effects of inflow conditions
Authors: SLESSOR M. D. , BOND C. L. , DIMOTAKIS P. E.
Published: July 2002

We report on the results from a set of incompressible, shear-layer
flow experiments,
at high Reynolds number
(Reδ≡ρΔUδT(x)/
μ≃2×105), in which the inflow
conditions of shear-layer formation were varied
(δT is the temperature-rise thickness
for chemically-reacting shear layers). Both inert and chemically-reacting
flows were
investigated, the latter employing the (H2+NO)/F2

chemical system in the kinetically-fast
regime to measure molecular mixing. Inflow conditions were varied by perturbing

each, or both, boundary layers on the splitter plate separating the two
freestream
flows, upstream of shear-layer formation. The results of the chemically-reacting
‘flip
experiments’ reveal that seemingly small changes in inflow conditions
can have a
significant influence not only on the large-scale structure and shear-layer
growth rate,
as had been documented previously, but also on molecular mixing and chemical-product

formation, far downstream of the inflow region.
Observation of cusps during the levelling of free surfaces in viscous
flows
Authors: BETELÚ S. , GRATTON R. , DIEZ J.
Published: July 2002

We experimentally study the formation of cusps at the free surfaces
of viscous fluids in three simple cases that portray possible natural or industrial processes. Two cases
concern levelling driven by gravity: the case (A) of a sinusoidal surface
and the case (B) of a single groove. In the third case (C), an initially sinusoidal
surface evolves under the action of a fast enough lateral compression that the effects
of gravity are negligible. Case (A) shows a critical aspect ratio above which the cusps
form. Case (B) allows a more detailed study of the evolution of the cuspidal structure,
which does not change in shape but reduces its size according to a simple power law
dependence in time. In case (C), cusps form even for small initial aspect ratios.
Direct numerical simulations of bubbly flows.
Part 1. Low Reynolds number arrays
Authors: ESMAEELI ASGHAR , TRYGGVASON GRÉTAR
Published: July 2002

Direct numerical simulations of the motion of two- and three-dimensional
buoyant
bubbles in periodic domains are presented. The full Navier–Stokes
equations are
solved by a finite difference/front tracking method that allows a fully
deformable
interface between the bubbles and the ambient fluid and the inclusion of
surface
tension. The governing parameters are selected such that the average rise
Reynolds
number is O(1) and deformations of the bubbles are small. The
rise velocity of a
regular array of three-dimensional bubbles at different volume fractions
agrees
relatively well with the prediction of Sangani (1988) for Stokes flow.
A regular array of
two- and three-dimensional bubbles, however, is an unstable configuration
and the
breakup, and the subsequent bubble–bubble interactions take place
by ‘drafting, kissing,
and tumbling’. A comparison between a finite Reynolds number two-dimensional

simulation with sixteen bubbles and a Stokes flow simulation shows that
the finite
Reynolds number array breaks up much faster. It is found that a freely
evolving
array of two-dimensional bubbles rises faster than a regular array and
simulations
with different numbers of two-dimensional bubbles (1–49) show that
the rise velocity
increases slowly with the size of the system. Computations of four and
eight three-dimensional bubbles per period also show a slight increase in the average
rise velocity
compared to a regular array. The difference between two- and three-dimensional

bubbles is discussed.
Three-dimensional analysis of the steady-state
shape and small-amplitude oscillation of a
bubble in uniform and non-uniform electric fields
Authors: LEE S. M. , KANG I. S.
Published: July 2002

A three-dimensional analysis is performed to investigate
the effects of an electric field
on the steady deformation and small-amplitude oscillation of a bubble in
dielectric
liquid. To deal with a general class of electric fields, an electric field
near the bubble is
approximately represented by the sum of a uniform field and a linear field.
Analytical
results have been obtained for steady deformation and modification of oscillation

frequency by using the domain perturbation method with the angular momentum

operator approach.

It has been found that, to the first order, the steady shape of a bubble
in an
arbitrary electric field can be represented by a linear combination of
a finite number
of spherical harmonics Yml,

where 0[les ]l[les ]4 and [mid ]m[mid ][les ]l. For the oscillation
about
the deformed steady shape, the overall frequency modification from the
value of
free oscillation about a spherical shape is obtained by considering two
contributions
separately: (i) that due to the deformed steady shape (indirect effect),
and (ii) that
due to the direct effect of an electric field. Both the direct and indirect
effects of
an electric field split the (2l+1)-fold degenerate frequency of

Yml modes, in the case

of free oscillation about a spherical shape, into different frequencies
that depend on
m. However, when the average is taken over the
(2l+1) values of m, the frequency
splitting due to the indirect effect via the deformed steady shape preserves
the average
value, while the splitting due to the direct effect of an electric field
does not.

The oscillation characteristics of a bubble in a uniform electric field
under the
negligible compressibility assumption are compared with those of a conducting
drop
in a uniform electric field. For axisymmetric oscillation modes, deforming
the steady
shape into a prolate spheroid has the same effect of decreasing the oscillation
frequency
in both the drop and the bubble. However, the electric field has different
effects on
the oscillation about a spherical shape. The oscillation frequency increases
with the
increase of electric field in the case of a bubble, while it decreases
in the case of a drop.
This fundamental difference comes from the fact that the electric field
outside the
bubble exerts a suppressive surface force while the electric field outside
the conducting
drop exerts a pulling force on the surface.
Primary acoustic instability of flames

propagating in tubes: cases of spray and

premixed gas combustion
Authors: CLANET CHRISTOPHE , SEARBY GEOFFREY , CLAVIN PAUL
Published: July 2002

This paper is concerned with the coupling mechanisms leading to the spontaneous

generation of sound during flame propagation in a tube open at one end. We consider

the cases of premixed gaseous combustion and of premixed spray combustion of

decane droplets in air. The flame front propagates from the open to the closed end of

a tube and, for a particular position, starts to amplify a longitudinal acoustic mode

of the tube. We call this mode the primary acoustic instability and focus our study on

the physical mechanisms responsible for sound amplification. Measured amplification

rates are compared to calculated values. In the gaseous case, it is shown that the

instability results from a coupling between the acoustic acceleration field and the

geometry of the flame front separating the burnt gases from the denser unburnt

mixture. The situation is quite different in the spray case. The primary acoustic

instability is much stronger and results from a modification of the inner structure of

the flame. This modification arises from the velocity lag of the droplets in the acoustic

velocity field, leading to a modulation of the fuel flux at the flame.
Linear stability of pathological detonations
Authors: SHARPE GARY J.
Published: July 2002

In this paper we investigate the linear stability of detonations in which the
underlying steady one-dimensional solutions are of the pathological type. Such detonations
travel at a minimum speed, which is greater than the Chapman–Jouguet (CJ) speed,
have an internal frozen sonic point at which the thermicity vanishes, and the unsupported
wave is supersonic (i.e. weak) after the sonic point. Pathological detonations
are possible when there are endothermic or dissipative effects present in the system.
We consider a system with two consecutive irreversible reactions A→B→C, with an
Arrhenius form of the reaction rates and the second reaction endothermic. We determine
analytical asymptotic solutions valid near the sonic pathological point for both
the one-dimensional steady equations and the equations for linearized perturbations.
These are used as initial conditions for integrating the equations. We show that, apart
from the existence of stable modes, the linear stability of the pathological detonation
is qualitatively the same as for CJ detonations for both one- and two-dimensional disturbances.
We also consider the stability of overdriven detonations for the system. We
show that the frequency of oscillation for one-dimensional disturbances, and the cell
size based on the wavenumber with the highest group velocity for two-dimensional
disturbances, are both very sensitive to the detonation speed for overdriven detonations
near the pathological speed. This dependence on the degree of overdrive is quite
different from that obtained when the unsupported detonation is of the CJ type.
An energy criterion for the linear stability of conservative flows
Authors: DAVIDSON P. A.
Published: July 2002

We investigate the linear stability of inviscid flows which are subject to a conservative
body force. This includes a broad range of familiar conservative systems, such as
ideal MHD, natural convection, flows driven by electrostatic forces and axisymmetric,
swirling, recirculating flow. We provide a simple, unified, linear stability criterion valid
for any conservative system. In particular, we establish a principle of maximum action
of the form

formula here

where η is the Lagrangian displacement,e is a measure of the disturbance energy,
T and V are the kinetic and potential energies, and L is the Lagrangian. Here d
represents a variation of the type normally associated with Hamilton's principle,
in which the particle trajectories are perturbed in such a way that the time of
flight for each particle remains the same. (In practice this may be achieved by
advecting the streamlines of the base flow in a frozen-in manner.) A simple test
for stability is that e is positive definite and this is achieved if L(η) is a maximum
at equilibrium. This captures many familiar criteria, such as Rayleigh's circulation
criterion, the Rayleigh–Taylor criterion for stratified fluids, Bernstein's principle for
magnetostatics, Frieman & Rotenberg's stability test for ideal MHD equilibria, and
Arnold's variational principle applied to Euler flows and to ideal MHD. There
are three advantages to our test: (i) d2T(η) has a particularly simple quadratic
form so the test is easy to apply; (ii) the test is universal and applies to any
conservative system; and (iii) unlike other energy principles, such as the energy-Casimir method or the Kelvin–Arnold variational principle, there is no need to
identify all of the integral invariants of the flow as a precursor to performing the
stability analysis. We end by looking at the particular case of MHD equilibria. Here
we note that when u and B are co-linear there exists a broad range of stable steady
flows. Moreover, their stability may be assessed by examining the stability of an
equivalent magnetostatic equilibrium. When u and B are non-parallel, however, the
flow invariably violates the energy criterion and so could, but need not, be unstable. In
such cases we identify one mode in which the Lagrangian displacement grows linearly
in time. This is reminiscent of the short-wavelength instability of non-Beltrami Euler
flows.
A transient Hartmann flow with heat transfer of a non-Newtonian fluid with suction and injection, considering the Hall effect
Authors: ATTIA HAZEM ALI , SAYED-AHMED MOHAMED EISSA
Published: July 2002

The transient Hartmann flow of an electrically conducting viscous incompressible
non-Newtonian power-law fluid between two parallel horizontal non-conducting
porous plates is studied with heat transfer, without neglecting the Hall
effect. A sudden uniform and constant pressure gradient, an external uniform magnetic
field that is perpendicular to the plates, and uniform suction and injection
through the surface of the plates are applied. The two plates are kept at different
but constant temperatures, while the Joule and viscous dissipations are taken into
consideration. Numerical solutions for the governing nonlinear momentum and energy
equations are obtained using finite difference approximations. The effect of
the Hall term, the parameter describing the non-Newtonian behavior, and the velocity
of suction and injection on both the velocity and temperature distributions
as well as the dissipation terms are examined.
Generation of axial and lateral magnetic fields
in a laser-produced plasma
Authors: BHATTACHARYYA B. , SANYAL URMI
Published: July 2002

The generation of axial and lateral magnetic fields due to the
interaction of
intense laser fields with a plasma is investigated analytically. For a

CO2 laser of
10.6 μm wavelength and 5×1014 W cm−2

power flux with a plasma of
temperature 3 keV, the numerical results show that the magnitude of the

lateral magnetic field dominates over the axial field, and the peak value
of the
lateral field is at less than the critical density, whereas the axial magnetic
field
peaks at the critical density level. This axial field combined with the
lateral field
may allow the construction of a new type of tokamak, and may also be
important for studying energy transport in laser-fusion schemes.
The K5 Gamble: National Defence and Nation Building under the People's Republic of Kampuchea
Authors: Slocomb Margaret
Published: July 2002

The K5 Plan for the defence of the Cambodian–Thai border was the response of the People's Republic of Kampuchea and its Vietnamese mentors to the threat posed by the resistance forces, particularly the Khmer Rouge, to its efforts to rebuild the nation and consolidate its administration. The very real defence gains, however, were made at the cost of bitter popular resentment over the way those gains were made.
Population biology and growth of three sympatric species of intertidal hermit crabs in south-eastern Brazil
Authors: Turra Alexander , Leite Fosca P.P.
Published: July 2002

Hermit crab populations have been described in different habitats and latitudes but few studies focused on coexisting populations. Such information is especially important to evaluate the effect of coexistence in the population biology of such organisms. This study was done in the intertidal region of Pernambuco Islet, São Sebastião Channel, south-eastern Brazil. Random samples of crabs were taken monthly during one year to evaluate their size and sex. The three coexisting Clibanarius populations (C. antillensis, C. sclopetarius, and C. vittatus) showed similar patterns of sex ratio (skewed for females), sexual dimorphism (males larger than females), recruitment (February to June) and population growth but differed in size structure (Cs>Cv>Ca) and reproductive activity over the year. Population growth was estimated using the von Bertalanffy growth function (VBGF) and revealed that the growth of these three populations was strongly reduced from August to January and that longevity varied from 42 to 48 months. Clibanarius antillensis showed continuous reproduction with high frequency of ovigerous females over the year while C. sclopetarius and C. vittatus had a reproductive peak in April and absence of ovigerous females in August/September. Coexistence seemed to influence population biology of these hermit crabs, given the relationship of their reproductive periods and growth patterns to the shell adequacy to the crabs. The overlap in reproductive peaks and recruitment periods may strengthen competition for shells. Comparisons of the reproductive patterns of the hermit crab populations recorded to date emphasize that reproduction and, consequently, life strategies of hermit crabs are not directly dependent on taxonomic or geographical proximity, but on their evolutionary histories and on local processes acting on each assemblage or population.