bluuebunny/crossref_metadata_2025 huggingface dataset:
CONVERGENCE AND CONFLICT IN EIGHTEENTH-CENTURY IRELAND
Authors: HILL JACQUELINE
Published: July 2002

Recent writing shows that eighteenth-century Irish society was both less and more divided than was supposed by Lecky, whose History of Ireland in the eighteenth century (now over a century old) dominated so much subsequent historiography. Because Lecky enjoyed access to records that were subsequently destroyed his work will never be entirely redundant, but this article looks at ways in which his views have been and continue to be modified. It surveys the various interpretative models now being used to open up the period, which invite comparisons not merely with England, Scotland, Wales, and colonial America but also with Europe. It also considers how that endlessly fascinating decade, the 1790s, has emerged from the spotlight turned on it by a plethora of bicentenary studies.
BETWEEN SAVIOUR AND VILLAIN: 100 YEARS
OF BISMARCK BIOGRAPHIES
Authors: URBACH KARINA
Published: July 2002

While non-German biographers of Bismarck have usually kept a healthy
distance from
their subject, German biographers have often allowed their political and
religious views to influence
their portraits. Most German historians of the ‘long nineteenth century’
were fascinated by, as Hegel
would have called it, the genius of such a ‘world historical individual’.
Their work greatly influenced
the images of Bismarck during the time of the Weimar Republic and the Third
Reich. Their
counterparts in the 1960s and 1970s, however focused critically on the
‘impersonal’ movements of the
Bismarckian empire. These, Marxist influenced, analyses did not include
any biographies. It was only
in the 1980s that three biographers achieved a politically detached evaluation
of the chancellor's
personality. With the centenary of Bismarck's death in 1998, a return
to the pre-1980s views can be
noticed in biographies of the chancellor. They threaten to oversimplify
Bismarck's personality and
government technique again.
Characterization of a germplasm collection of the
tropical pasture legume Centrosema brasilianum
in subhumid west Africa
Authors: PETERS M. , KRAMER H. , TARAWALI S. A. , SCHULTZE-KRAFT R.
Published: July 2002

The available world collection consisting of 257
accessions of the tropical pasture legume Centrosema
brasilianum (L.) Benth. was assessed between 1993 and
1995 in northern Nigeria to complement
existing knowledge on the genetic diversity of this species
and to identify accessions with high
agronomic potential for subhumid west Africa. The excellent
nutritive value and good dry matter
productivity of C. brasilianum and its
outstanding ability to remain green over extended dry periods
confirmed its potential as an important forage resource,
especially for the dry season, and indicated
its possible role in soil conservation. Two distinct groups,
comprising 10 and 11 accessions, were
identified for further evaluation in short fallow and pasture
systems, respectively. Accessions in the
first group had a fast establishment, very high yields in
the establishment year and good drought
tolerance but yields were low to average in subsequent years.
Accessions in the second group had
sustained high yields under grazing, a high competitive ability
and good drought tolerance.
The effect of seedbed condition on the grain yield and
quality of spring malting barley
Authors: CONRY M. J.
Published: July 2002

The effect of seedbed conditions at the time of sowing
on the grain yield and quality ex-farm of spring-sown
malting barley was examined in three experiments in the
south-east of Ireland in 1993–95.
Blenheim malting barley sown in good seedbed conditions gave
significantly (P<0·05) greater yields
(3·1–9·6% more) than the identically treated
crop, sown several days earlier, in less suitable seedbed
conditions in all three experiments, but there was no effect
on grain nitrogen content or the amount
of screenings. The better soil conditions gave significantly
(P<0·05) better plant emergence, a greater
number of fertile tillers and more grains per ear.
The effect of soil moisture on light interception and the
conversion coefficient for three landraces of bambara
groundnut (Vigna subterranea)
Authors: COLLINSON S. T. , BERCHIE J. , AZAM-ALI S. N.
Published: July 2002

Three landraces of bambara groundnut (Vigna subterranea (L.) Verdc.) were grown as crop stands
in controlled environment glasshouses at the Tropical Crops Research Unit, University of
Nottingham, in 1995. Two soil moisture treatments were imposed: irrigated to 90% field capacity
each week and irrigated to 60% field capacity until establishment (27 days after sowing) with no
further irrigation. Seasonal mean fractional interception varied between 0·20–0·37 for the droughted
treatments and 0·62–0·74 for the irrigated treatments, resulting in cumulative intercepted radiation of
228–350 MJ/m2 and 662–794 MJ/m2, respectively. The maximum total dry matter (DM) produced
was 5·8 t/ha at final harvest (145 days after sowing) with a pod yield of 2·7 t/ha. Under moisture
stress there was little difference in DM production between landraces, with the highest total DM of
1·1 t/ha and a pod yield of 0·05 t/ha, representing a harvest index of 0·05 compared with an average
of 0·46 for the irrigated treatments. The conversion coefficient was reduced from 1·00 under irrigation
to 0·51 g DM/MJ radiation intercepted by soil moisture stress. Two of the landraces showed adaptive
mechanisms to avoid drought; these are discussed in relation to maximizing seasonal radiation
interception.
Effect of sward cutting management on the relative
performance of perennial ryegrass varieties
Authors: GILLILAND T. J. , MANN R. L.
Published: July 2002

The performance potentials of six perennial ryegrass varieties for conservation or grazing use were
compared between 1994 and 1996 in N. Ireland. They were maintained, either under constant lax
defoliation (conservation) or constant severe defoliation (simulated grazing) management for 3 years,
or annually alternated between these two managements with the changeover taking place either in
autumn or at the first cut of the following year. Starting one set with lax defoliation in the first year
and the other with severe defoliation created duplicates of these two alternating treatments. The
results showed that variety yield differed depending on the season and the management imposed and
there were differential responses to the various treatments. Conducting an alternating management
system that implemented the management change in autumn provided a valid estimate of yield
performance potential for both simulated grazing and conservation use, compared to constant
management systems. Although significant differences in variety ranking between lax defoliation and
severe defoliation management yields were only observed in the third year, the study showed that if
the management change was implemented in autumn, the yield potential of varieties in the following
year was not affected by the preceding year's management regime. Leaving a longer sward (6 cm) to
over-winter increased the spring performance of the varieties in some years, compared to a shorter
sward (3 cm), which may have implications for grazing management. There were also indications that
imposing an alternating management system might alter the absolute magnitude of the sward density
ratings relative to a constantly managed system, though variety rankings would remain unaffected.

It was concluded that the current alternating management testing system used to evaluate
candidate varieties for UK National or regional recommended lists, does not cause any variety to be
unfairly advantaged or disadvantaged.
Shifting Perspectives on American Exceptionalism:

Recent Literature on American Labor Relations and Labor Politics
Authors: GERBER LARRY G.
Published: July 2002

Nearly a decade ago, historian Alan Dawley proclaimed the idea
of

American exceptionalism to be dead and buried. Dawley's pronouncement

proved premature given the subsequent publication of books by Byron

Shafer and Seymour Martin Lipset reaffirming the concept, as well as

studies by Ian Tyrell, George Fredrickson, and others addressing the

issue. However, the motion of American uniqueness so widely accepted

a generation ago has come under serious challenge, and new conceptions

of American “distinctiveness” or “variability”

have emerged in recent scholarship.
FAMILY SIZE AND SEX PREFERENCES AND EVENTUAL FERTILITY IN BOTSWANA
Authors: CAMPBELL EUGENE K. , CAMPBELL PUNI G.
Published: July 2002

Botswana is one of the sub-Saharan countries where actual fertility
has declined. This study examines the fertility preferences of both men and
women and shows that fertility intentions have a significant influence on
future fertility behaviour. Fertility preferences are relatively low and there
is no significant difference between those of men and women. Men's preference
for sons influences desired family size and eventual fertility. For women as
well as men, child survival is an important factor. Women's income is also
influential.
Determination of somatic cells in milk by solid phase cytometry
Authors: D'HAESE EVA , NELIS HANS J. , REYBROECK WIM
Published: July 2002

The somatic cell count of milk is routinely determined by the fluoro-opto-electronic
method and sometimes by the direct epifluorescent filter technique
(DEFT). This paper investigates the potential of solid phase cytometry (SPC), a
novel technique combining aspects of both the fluoro-opto-electronic method and
epifluorescence microscopy for somatic cell counting. In SPC, cells are retained on a
membrane filter, fluorescently labelled and automatically detected on the entire
membrane filter by means of a laser scanning instrument (ChemScan). Fluorescent
spots can be visually inspected by an epifluorescence microscope with a computer-driven moving stage. The performance of SPC was compared with that of the fluoro-opto-electronic
method using a Fossomatic 360 instrument for 68 milk samples with
varying somatic cell counts (103–106/ml). The sample throughput and repeatability
of SPC were inferior to those of the Fossomatic method and statistical analysis of the
method comparison data using the approach of J. M. Bland & D. G. Altman (The
Lancet 1986 February 8 pp 307–310) revealed a poor comparability between the two
methods. Moreover, problems of milk filterability and the interference of fluorescent
particles presently hamper the routine application of SPC. Nevertheless, this method
represents the first example of the application of SPC to milk.
Genetic polymorphism of the caprine kappa casein gene
Authors: HABIB YAHYAOUI M. , COLL AGUSTINA , SANCHEZ ARMAND , FOLCH JOSEP M.
Published: July 2002

Polymorphism in the goat kappa casein gene was studied using the base excision sequence scanning (BESS) method and sequencing. Seven polymorphic sites, corresponding to single nucleotide transversions were detected. Three of these were silent mutations while the other four produced amino acid substitutions. The association between these polymorphic sites was investigated, which resulted in the identification of three goat kappa casein alleles, designated A, B, and C. Protocols for rapid genotyping of the C variant were developed by polymerase chain reaction–restriction fragment length polymorphism using Alw44I and BseNI restriction endonucleases. The occurrence of this allele was found to be very low in Spanish breeds but more frequent in the French Saanen goat. Further studies among different goat populations are necessary to establish the distribution of these alleles and their effects on the quality and functional properties of milk.
Effect of localised antibiotic infusions applied to the teat-canal and teat sinus at drying-off on mastitis in the dry-period and at calving
Authors: WOOLFORD MURRAY W. , WILLIAMSON JOHN H. , DAY TONY M. , LACY-HULBERT S. JANE , HENDERSON HAROLD V.
Published: July 2002

An experiment using three New Zealand herds and a total of 632 cows, examined the effect of localised prophylactic treatments with antibiotic at drying-off on the incidence of new intramammary infection during the dry period and at calving. Antibiotic was infused either into the teat canal (0·22 g of dry-cow formulation) or the teat sinus (3·1 g of lactating-cow formulation) of uninfected quarters to eliminate any bacteria present in these locations at the last milking of lactation. These treatments were compared with a negative control (nil treatment) and a positive antibiotic control (infusion of 3·6 g of dry-cow formulation). All antibiotic formulations used the same active ingredient, sodium cloxacillin. No significant reduction in new dry period clinical mastitis was observed for the two localised treatments whereas the positive control treatment achieved 100% reduction in new clinical mastitis compared with untreated control quarters. A 41% reduction (P<0·05) in new Streptococcus uberis infections at calving was associated with the teat canal antibiotic treatment, compared with an 82% reduction (P<0·001) for the positive antibiotic control. Both localised treatments showed a reduced incidence of new intramammary infection (P<0·001) when pooled across periods and pathogens. Teats receiving either the teat canal antibiotic treatment or a full infusion of long acting dry-cow antibiotic had a lower incidence of open teat canals (P<0·05) at 3 weeks after drying-off.
Temperature characterization of psychrotrophic and mesophilic
Bacillus species from milk
Authors: GARCÍA-ARMESTO M. ROSARIO , SUTHERLAND ALASTAIR D.
Published: July 2002

A total of 50 isolates of Bacillus spp. and one
reference strain were
investigated for their growth at 6·5°C for 10 d, 30°C for

3 d and 40°C for 2 d. The
results obtained differentiated three physiological groups:
one clearly psychrotrophic
(able to grow at 6·5°C in 10 d, but not at 40°C in 2 d),

one intermediate in
psychrotrophy (it grew at both 40 and 6·5°C) and one
mesophilic (capable of growth
at 30 and 40°C, but not at 6·5°C). The proportion of strains

in the second group was
higher among isolates of B. cereus than for other
Bacillus spp. However, the
proportion of real mesophilic strains was lower for B. cereus

isolates. Psychrotrophic
B. cereus grew better at both 6·5 and 30°C than
other psychrotrophic Bacillus spp.
Using eight strains, a correlation between differential growth at mesophilic

temperatures (count at 30°C minus count at 40°C) and a standard
psychrotrophic
count at 6·5°C for 10 d (r=0·95) was
obtained in mixed cultures when the
psychrotrophic flora count was [les ]1 log (cfu/ml) lower than
the mesophilic count.
Analytic adjoint solutions for the quasi-one-dimensional Euler equations
Authors: GILES MICHAEL B. , PIERCE NILES A.
Published: July 2002

The analytic properties of adjoint solutions are examined for the quasi-one-dimensional
Euler equations. For shocked flow, the derivation of the adjoint problem
reveals that the adjoint variables are continuous with zero gradient at the shock,
and that an internal adjoint boundary condition is required at the shock. A Green's
function approach is used to derive the analytic adjoint solutions corresponding to supersonic,
subsonic, isentropic and shocked transonic flows in a converging–diverging
duct of arbitrary shape. This analysis reveals a logarithmic singularity at the sonic
throat and confirms the expected properties at the shock.
Wake formation around islands in oscillatory laminar shallow-water flows. Part 1. Experimental investigation
Authors: LLOYD PETER M. , STANSBY PETER K. , CHEN DAOYI
Published: July 2002

An experimental investigation of oscillatory shallow-water flow around islands has
been undertaken to determine the dependence of wake formation on Keulegan–Carpenter
number, KC = UoT/D,
and stability parameter, S = cfD/h, where
Uo is amplitude of velocity oscillation, T is oscillation period,
D is a representative island diameter, cf
is friction coefficient and h is water depth. Two geometries are
investigated: a vertical cylinder and a conical island with a small side slope of 8°.
Existing experimental results for current flow around the same geometries have shown
the influence of the stability parameter. Predominantly laminar flows are investigated
and the flows are subcritical.

Four modes of wake formation have been identified for both geometries: one with
symmetric attached counter-rotating vortices only forming in each half-cycle, one with
vortex pairs forming symmetrically in addition in each half-cycle, one with vortex
pairs forming with some asymmetry and one with complex vortex shedding. The last
results from one of the attached vortices crossing to the opposite side of the body
during flow reversal; in the other cases the attached vortices are convected back
on the same sides. For convenience these formations are called: symmetric without
pairing, symmetric with pairing, sinuous with pairing and vortex shedding. They are
shown on KC/S planes for both geometries. Numerical modelling of the flows for
the conical island, based on the three-dimensional shallow-water equations with the
hydrostatic pressure assumption, is undertaken in Part 2 (Stansby & Lloyd 2001).
Slow waves of boiling under hot water depressurization
Authors: IVASHNYOV OLEG E. , IVASHNEVA MARINA N. , SMIRNOV NICKOLAI N.
Published: July 2002

Experimental studies of hot water depressurization show that the pressure in a vessel,
just after it is opened, drops much lower than the pressure of saturation but the
liquid does not boil uniformly throughout the vessel. Essentially, liquid boiling begins
only on the arrival of a ‘slow wave’ of rarefaction which moves at a low speed of
approximately 10 m s−1 from the open end deep into the vessel.

To explain this phenomenon we suggest a model that takes into account the
difference in phase velocities. Although this difference in bubble flows is only about
1 m s−1 it proves to be sufficient to cause bubble breakup. Using this model we
obtained the ‘slow wave of boiling’ in a numerical experiment that was in good
agreement with the physical experiment.
Currents induced by long waves propagating towards a beach over a wavy bed
Authors: KYOTOH H. , FUJII S. , TO D. V.
Published: July 2002

For the understanding of longshore currents along a natural beach, the effects of
bottom unevenness are considered to be important, especially for the flow in the
swash zone. Currents in the swash zone are strongly influenced by the bed slope
because the effect of gravity overwhelms the effect of the depth change. In the present
paper, we investigate these effects and focus on waves propagating from offshore over
a flat ocean basin of constant depth to a beach with a sloping wavy bottom. The waves
are incident at a small angle to the beach normal, and the bed slope in the alongshore
direction is varied slowly. To simplify the problem, only cnoidal waves and solitary
waves are considered and the bed level is varied sinusoidally in the longshore direction.

A perturbation method is applied to the two-dimensional nonlinear shallow water
equation (two-dimensional NLSWE) for the wave motion in order to generate a
more simplified model of wave dynamics consisting of a one-dimensional NLSWE
for the direction normal to the beach and an equation for the alongshore direction.
The first equation, the one-dimensional NLSWE, is solved by Carrier & Greenspan's
transformation. The solution of the second one is found by extending Brocchini
& Peregrine's solution for a flat beach. Two methods for the solution of the one-
dimensional NLSWE are introduced in order to get a solution applicable to large-amplitude swash motions, where the amplitude is comparable to the beach length.
One is the Maclaurin expansion of the solution around the moving shoreline, and
the other is Riemann's representation of the solution, which exactly satisfies the one-dimensional NLSWE and the boundary conditions. After doing a consistency check
by confirming that Riemann's method, a numerical solution, agrees with the exact
solution for an infinitely long, sloping beach, we assumed that the Maclaurin series
solution can also describe wave motion in the swash zone properly not only for this
model but also for our ‘wavy’, finite beach model.

The solution obtained from the Maclaurin series is then plugged into the equation
for the alongshore direction to calculate the shore currents induced by wave run-up
and back-wash motions, where a ‘weakly two-dimensional solution’ is derived from
geometrical considerations. The results show that since the water depth near the
shoreline is comparable to the bed level fluctuations, the flow is strongly affected
by the bed unevenness, leading to recognizable changes in shoreline movement and
the time-averaged velocity and the mass flux of the flow in the swash zone. More
specifically, the inhomogeneity of the alongshore mass flux generates offshore currents
because of the continuity condition for the fluid mass.
Measurement and computation of hydrodynamic coupling at an air/water interface with an insoluble monolayer
Authors: HIRSA AMIR H. , LOPEZ JUAN M. , MIRAGHAIE REZA
Published: July 2002

The coupling between a bulk vortical flow and a surfactant-influenced air/water
interface has been examined in a canonical flow geometry through experiments and
computations. The flow in an annular region bounded by stationary inner and outer
cylinders is driven by the constant rotation of the floor and the free surface is initially
covered by a uniformly distributed insoluble monolayer. When driven slowly, this geometry
is referred to as the deep-channel surface viscometer and the flow is essentially
azimuthal. The only interfacial property that affects the flow in this regime is the surface
shear viscosity, μs, which is uniform on the surface due to the vanishingly small
concentration gradient. However, when operated at higher Reynolds number, secondary
flow drives the surfactant film towards the inner cylinder until the Marangoni
stress balances the shear stress on the bulk fluid. In general, the flow can be influenced
by the surface tension, σ, and the surface dilatational viscosity, κs,
as well as μs.
However, because of the small capillary number of the present flow, the effects of surface
tension gradients dominate the surface viscosities in the radial stress balance, and the
effect of μs can only come through the azimuthal stress.
Vitamin K1 was chosen for
this study since it forms a well-behaved insoluble monolayer on water and μs is essentially
zero in the range of concentration on the surface, c, encountered. Thus the effect
of Marangoni elasticity on the interfacial stress could be isolated. The flow near the
interface was measured in an optical channel using digital particle image velocimetry.
Steady axisymmetric flow was observed at the nominal Reynolds number of 8500. A
numerical model has been developed using the axisymmetric Navier–Stokes equations
to examine the details of the coupling between the bulk and the interface. The nonlinear
equation of state, σ(c), for the vitamin K1 monolayer was measured and utilized
in the computations. Agreement was demonstrated between the measurements and
computations, but the flow is critically dependent on the nonlinear equation of state.
The vaporization of a liquid front moving

through a hot porous rock. Part 2. Slow injection
Authors: WOODS ANDREW W. , FITZGERALD SHAUN D.
Published: July 2002

We present a series of similarity solutions to describe the

temperature field as liquid

spreads from a line source into a porous rock saturated with liquid of
higher

temperature. We identify slow and fast flow regimes. In the slow flow

regime, the liquid

is heated to the far-field temperature by conduction of heat from the

far field. In the

fast flow regime, there is negligible conduction of heat from

the far field. Instead, the

liquid is heated to the far-field temperature by cooling a

region of the host rock near

the source, and an internal boundary layer develops within the newly injected
liquid.

We successfully test our quantitative theoretical predictions

with a series of laboratory

experiments in which water was injected into a consolidated bed of sand
filled with

liquid of different temperature. We extend our model to describe the vaporization

of liquid as it spreads slowly from a central source into a superheated
porous rock.

A further family of similarity solutions shows that the rate of vaporization
depends

upon the injection rate as well as upon the initial superheat of

the reservoir. For high

injection rates, the liquid is typically heated to the interface

temperature long before

reaching the interface. The rate of vaporization then becomes independent
of the

initial liquid temperature, and depends mainly on the reservoir superheat.
For lower

injection rates, heat is conducted from ahead of the boiling front into
the liquid.

As a result, for progressively smaller injection rates, an

increasing fraction of the

liquid vaporizes, until virtually all the liquid boils, and only

a very small liquid zone

develops in the rock. Again, we successfully test our theoretical predictions
with a

laboratory experiment in which liquid water was injected into a superheated
layer of

permeable sandstone.
Localized mixing due to a breaking internal wave ray at a sloping
bottom
Authors: DE SILVA I. P. D. , IMBERGER J. , IVEY G. N.
Published: July 2002

A laboratory experiment was conducted to investigate the

characteristics of turbulence

generated by an internal wave ray breaking on a sloping bed. The

width of the incident

wave ray was small compared to the bed length, so that an isolated

turbulent patch was

generated by the breaking process, a configuration unique to the present
study. The

parameter range covered subcritical, critical and supercritical frequencies.
Flow

visualization and velocity measurements revealed that near critical

conditions the flow

was confined to a narrow region above the bed and, contrary to

expectations, critical

waves showed a weak turbulence field. Subcritical and supercritical

reflection resembled

wave–wave interaction between the incident and the reflected waves
and showed

comparable centred displacement lengthscales. As the incident waves became

progressively supercritical instabilities were first initiated

away from the bed. For

supercritical waves the centred displacement lengthscale and the turbulent
Reynolds

number both increased steadily up to about γ≈2,

after which they started to decrease

(γ=ω/ωc, where ω

is the frequency of the incident wave and

ωc=Nsinβ is the critical

frequency for an ambient uniform stratification of magnitude N

and a bed angle of β).

For subcritical waves an increase in the centred displacement lengthscale
and the

turbulent Reynolds number was also observed. The mixed fluid generated
at the

boundary collapsed into the fluid interior in the form of a

horizontal two-dimensional

viscous–buoyancy intrusion: the efficiency of mixing was,

however, very small and no

measurable change in the mean density gradient was observed over the duration
of the

experiments.
Direct numerical simulation of a three-dimensional temporal mixing
layer with
particle dispersion
Authors: LING WEI , CHUNG J. N. , TROUTT T. R. , CROWE C. T.
Published: July 2002

The three-dimensional mixing layer is characterized by both two-dimensional
and
streamwise large-scale structures. Understanding the effects of those large-scale
structures
on the dispersion of particles is very important. Using a pseudospectral
method,
the large-scale structures of a three-dimensional temporally developing
mixing layer
and the associated dispersion patterns of particles were simulated. The
Fourier expansion
was used for spatial derivatives due to the periodic boundary conditions

in the streamwise and the spanwise directions and the free-slip boundary
condition
in the transverse direction. A second-order Adam–Bashforth scheme
was used in
the time integration. Both a two-dimensional perturbation, which was based
on the
unstable wavenumbers of the streamwise direction, and a three-dimensional
perturbation,
derived from an isotropic energy spectrum, were imposed initially. Particles
with
different Stokes numbers were traced by the Lagrangian approach based on
one-way
coupling between the continuous and the dispersed phases.

The time scale and length scale for the pairing were found to be twice
those for the
rollup. The streamwise large-scale structures develop from the initial
perturbation and
the most unstable wavelength in the spanwise direction was found to be
about two
thirds of that in the streamwise direction. The pairing of the spanwise
vortices was also
found to have a suppressing effect on the development of the three-dimensionality.

Particles with Stokes number of the order of unity were found to have the
largest
concentration on the circumference of the two-dimensional large-scale structures.

The presence of the streamwise large-scale structures causes the variation
of the
particle concentrations along the spanwise and the transverse directions.
The extent
of variation also increases with the development of the three-dimensionality,
which
results in the ‘mushroom’ shape of the particle distribution.
Vorticity dynamics in a breaking internal gravity wave. Part 2.
Vortex interactions and transition to turbulence
Authors: FRITTS DAVID C. , ARENDT STEVE , ANDREASSEN ØYVIND
Published: July 2002

A companion paper (Part 1) employed a three-dimensional numerical
simulation
to examine the vorticity dynamics of the initial instabilities of a breaking
internal
gravity wave in a stratified, sheared, compressible fluid. The present
paper describes
the vorticity dynamics that drive this flow to smaller-scale, increasingly
isotropic
motions at later times. Following the initial formation of discrete and
intertwined
vortex loops, the most important interactions are the self-interactions
of single vortex
tubes and the mutual interactions of multiple vortex tubes in close proximity.
The
initial formation of vortex tubes from the roll-up of localized vortex
sheets gives the
vortex tubes axial variations with both axisymmetric and azimuthal-wavenumber-2

components. The axisymmetric variations excite axisymmetric twist waves
or Kelvin
vortex waves which propagate along the tubes, drive axial flows, deplete
the tubes'
cores, and fragment the tubes. The azimuthal-wavenumber-2 variations excite
m=2
twist waves on the vortex tubes, which undergo strong amplification and
unravel
single vortex tubes into pairs of intertwined helical tubes; the vortex
tubes then
burst or fragment. Reconnection often occurs among the remnants of such
vortex
fragmentation. A common mutual interaction is that of orthogonal vortex
tubes,
which causes mutual stretching and leads to long-lived structures. Such
an interaction
also sometimes creates an m=1 twist wave having an approximately
steady helical
form as well as a preferred sense of helicity. Interactions among parallel
vortex tubes
are less common, but include vortex pairing. Finally, the intensification
and roll-up
of weaker vortex sheets into new tubes occurs throughout the evolution.
All of these
vortex interactions result in a rapid cascade of energy and enstrophy toward
smaller
scales of motion.
Numerical studies of two-dimensional Faraday
oscillations of inviscid fluids
Authors: WRIGHT JEFF , YON STEVE , POZRIKIDIS C.
Published: July 2002

The dynamics of two-dimensional standing periodic waves at the interface between
two inviscid fluids with different densities, subject to monochromatic oscillations
normal to the unperturbed interface, is studied under normal- and low-gravity conditions.
The motion is simulated over an extended period of time, or up to the point where
the interface intersects itself or the curvature becomes very large, using two numerical
methods: a boundary-integral method that is applicable when the density of one
fluid is negligible compared to that of the other, and a vortex-sheet method that is
applicable to the more general case of arbitrary densities. The numerical procedure
for the boundary-integral formulation uses a global isoparametric parametrization
based on cubic splines, whereas the numerical method for the vortex-sheet formulation
uses a local boundary-element parametrization based on circular arcs. Viscous
dissipation is simulated by means of a phenomenological damping coefficient added
to the Bernoulli equation or to the evolution equation for the strength of the vortex
sheet. A comparative study reveals that the boundary-integral method is generally
more accurate for simulating the motion over an extended period of time, but the
vortex-sheet formulation is significantly more efficient. In the limit of small deformations,
the numerical results are in excellent agreement with those predicted by the
linear model expressed by Mathieu's equation, and are consistent with the predictions
of the Floquet stability analysis. Nonlinear effects for non-infinitesimal amplitudes
are manifested in several ways: deviation from the predictions of Mathieu's equation,
especially at the extremes of the interfacial oscillation; growth of harmonic waves with
wavenumbers in the unstable regimes of the Mathieu stability diagram; formation
of complex interfacial structures including paired travelling waves; entrainment and
mixing by ejection of droplets from one fluid into the other; and the temporal period
tripling observed recently by Jiang et al. (1998). Case studies show that the surface
tension, density ratio, and magnitude of forcing play a significant role in determining
the dynamics of the developing interfacial patterns.
Linear and nonlinear interactions between
a columnar vortex and external turbulence
Authors: MIYAZAKI TAKESHI , HUNT JULIAN C. R.
Published: July 2002

The structure of initially isotropic homogeneous turbulence interacting with a columnar
vortex (with circulation Γ and radius σ), idealized both as a solid cylinder
and a hollow core model is analysed using the inhomogeneous form of linear rapid distortion
theory (RDT), for flows where the r.m.s. turbulence velocity u0 is small
compared with Γ/σ. The turbulent eddies with scale Γ
are distorted by the mean velocity gradient and also, over a distance Γ
from the surface of the vortex, by their direct impingement onto it, whether it is solid or
hollow. The distortion of the azimuthal component of turbulent vorticity by the differential
rotation in the mean flow around the columnar vortex causes the mean-square radial velocity
away from the cylinder to increase as
(Γt/2πr2)2
(Γx/r)u20, when
(r − σ) > Γx, but on the surface of
the vortices ((r − σ) < Γx) where
〈u2r〉 is reduced,
〈u2z〉 increases to the same order, while the
other components do not grow. Statistically, while the vorticity field remains asymmetric,
the velocity field of small-scale eddies near the vortex core rapidly becomes
axisymmetric, within a period of two or three revolutions of the columnar vortex.
Calculation of the distortion of small-scale initially random velocity fields shows
how the turbulent eddies, as they are wrapped around the columnar vortex, become
like vortex rings, with similar properties to those computed by Melander & Hussain
(1993) using a fully nonlinear direct numerical simulation. A mechanism is proposed
for how interactions between the external turbulence and the columnar vortex can
lead to non-axisymmetric vortex waves being excited on the vortex and damped
fluctuations in its interior. If the columnar vortex is not significantly distorted by
these linear effects, estimates are made of how nonlinear effects lead to the formation
of axisymmetric turbulent vortices which move as result of their image vorticity (in
addition to the self-induction velocity) at a velocity of order
u0tΓ/σ2 parallel to the vortex. Even
when the circulation (γ) of the turbulent vortices is a small fraction of
Γ, they can excite self-destructive displacements through resonance on a time
scale σ/u0.
Surprises in viscous fingering
Authors: TANVEER S.
Published: July 2002

In this paper, we review some aspects of viscous fingering in a Hele-Shaw cell that at
first sight appear to defy intuition. These include singular effects of surface tension
relative to the corresponding zero-surface-tension problem both for the steady and
unsteady problem. They also include a disproportionately large influence of small
effects like local inhomogeneity of the flow field near the finger tip, or of the leakage
term in boundary conditions that incorporate realistic thin-film effects. Through simple
explicit model problems, we demonstrate how such properties are not unexpected for
a system approaching structural instability or ill-posedness.
The extraction riddle: just what are we missing?
Authors: D. LEVINE ROBERT
Published: July 2002

Paul M. Postal,Three investigations of extraction. Cambridge, MA: MIT Press, 1998. Pp. x+215.
Plasma-turbulence suppression and transport-barrier formation by externally driven radiofrequency waves in spherical tokamaks
Authors: KOMOSHVILI K. , CUPERMAN S. , BRUMA C.
Published: July 2002

Turbulent transport of heat and particles is the principle obstacle confronting
controlled fusion today. We investigate quantitatively the suppression of
turbulence and formation of transport barriers in spherical tokamaks by sheared
electric fields generated by externally driven radiofrequency (RF) waves, in the
frequency range ωA ∼ ω < ωci
(where ωA and ωci are the Alfvén and ion cyclotron
frequencies).

This investigation consists of the solution of the full-wave equation for a spherical
tokamak in the presence of externally driven fast waves and the evaluation
of the power dissipation by the mode-converted Alfvén waves. This in turn provides
a radial flow shear responsible for the suppression of plasma turbulence. Thus
a strongly nonlinear equation for the radial sheared electric field is solved, and
the turbulent transport suppression rate is evaluated and compared with the ion
temperature gradient (ITG) instability increment.
Self-similar expansion of dusty plasmas
Authors: PILLAY S. R. , SINGH S. V. , BHARUTHRAM R. , YU M. Y.
Published: July 2002

The radially symmetric self-similar expansion of a dusty plasma
is
investigated in
cylindrical and spherical geometries. The electrons and ions are assumed
to be in
Boltzmann equilibria, while the dynamics of the dust particles is governed
by the
fluid equations. The effects of finite dust pressure as well as
dust-charge variation are included.
Energy dynamics in linear MHD with ion parallel viscosity
Authors: OUGHTON SEAN
Published: July 2002

Analytic results for the time dependences of the kinetic and magnetic
energies of
an incompressible magneto fluid threaded by a strong uniform magnetic field
B0
are obtained. The governing equations are the linearised magnetohydrodynamic
(MHD) ones, but with the conventional Laplacian dissipation replaced by
ion
parallel viscous effects. The behaviour is shown to depend on the relative
sizes of the
Alfvén frequency and the viscous and resistive dissipation rates.
For many cases
equipartition of the kinetic and magnetic energy holds at the (Fourier)
modal level.
An important exception to this behaviour occurs for two-dimensional fluctuations,
that is when the wavevectors are perpendicular to B0.
Zinc, copper and chlorophyll-derivatives in the polychaete Owenia fusiformis
Authors: Gibbs P.E. , Burt G.R. , Pascoe P.L. , Llewellyn C.A. , Ryan K.P.
Published: July 2002

An earlier study of metals in the polychaete Owenia fusiformis showed that individuals within intertidal populations were remarkably variable in terms of whole-body concentrations of zinc and copper. Four populations have now been studied, two in south Cornwall (Fal Estuary and Par Sands) and one each in east Devon (Torre Abbey Sands) and north Brittany (Grève de St Michel). Investigations of the distributions of zinc and copper within the body have demonstrated that consistently zinc is concentrated in the middle body whilst copper increases to a maximum posteriorly. Zinc is accumulated in the mid-gut cells in the form of numerous spherules, 1–2 μm in diameter: X-ray microanalysis shows these to be largely composed of zinc phosphate but containing also magnesium, calcium and iron, together with sulphur and chlorine. Viewed under the microscope the spherules are greenish due to a pigment identified by high performance liquid chromatography absorption scanning as a pheophorbide-like chlorophyll-degradation product. In contrast, copper is widely distributed throughout the body and much is deposited as small granules, 0.2–0.3 μm in diameter, in laminar groupings in hypodermal and peri-intestinal tissues. The identity of the green pigment responsible for the characteristic body colour of O. fusiformis has not been specifically determined but it appears to have a copper basis since dark-green tissues have a significantly higher copper content than those with a light-green colour. The possible role of chlorophyll degradation products in zinc and copper uptake is discussed.
An unusual suctorial montacutid bivalve from the deep Atlantic
Authors: Allen J.A.
Published: July 2002

The shell and internal anatomy of the montacutid bivalve Mysella verrilli is described for the first time. The species is remarkable in that the oesophagus has developed into a suctorial proboscis. This has been accompanied by the loss of the palps. In addition the gonads have been extended from the dorsal part of the body to form two gill-like extensions to which the reduced inner demibranchs attach along the postero–ventral margin. Mysella verrilli broods its young in the mantle cavity to the late veliger stage before releasing them. It is believed that the species is probably a suctorial ectoparasite on a soft-bodied benthic invertebrate.
Population structure and shell use in the hermit crab, Clibanarius erythropus: a comparison between Mediterranean and Atlantic shores
Authors: Benvenuto Chiara , Gherardi Francesca
Published: July 2002

Two populations of Clibanarius erythropus from Mediterranean and Atlantic rocky shores were studied to provide data on morphometry, population structure and shell use under different environmental contexts. Hermit crab sex and size were analysed as well as genus, dimension and status of the inhabited shells. A comparison between the two populations gave particular emphasis to the morphological and eco-ethological plasticity of this hermit species.
The distribution of anchovy
Engraulis encrasicolus in the northern Irish Sea from 1991 to 1999
Authors: Armstrong M.J. , Dickey-Collas M. , McAliskey M. , McCurdy W.J. , Burns C.A. , Peel J.A.D.
Published: July 2002

Since 1995, research cruise catches of anchovy Engraulis
encrasicolus (Pisces: Engraulidae) have increased in the Irish Sea. Their
distribution shows distinct seasonality with anchovy being found in the deeper
waters of the western Irish Sea in the spring and spreading out into the eastern
Irish Sea by summer and autumn. Their length distributions show two modes at
7–11 cm and 13–16 cm.
Behavioural observations on the scavenging fauna of the Patagonian slope
Authors: Collins Martin A. , Yau Cynthia , Nolan Conor P. , Bagley Phil M. , Priede Imants G.
Published: July 2002

The scavenging fauna of the Patagonian slope (900–1750 m), east of the Falkland Islands was investigated using the Aberdeen University Deep Ocean Submersible (AUDOS), an autonomous baited camera vehicle designed to photograph scavenging fish and invertebrates. The AUDOS was deployed on ten occasions in Falkland waters. Nine experiments were of 10–14 h duration and baited with 800 g of squid and one experiment lasted six days, baited with a 10 kg toothfish (Dissostichus eleginoides). Analysis of photographs revealed considerable patchiness in the composition of the scavenging fauna. Hagfish (Myxine cf. fernholmi) dominated three of the shallower experiments including the 6-d experiment, arriving quickly from down-current, holding station at the bait and consuming the soft tissues first, with consumption rates of up to 200 g h−1. In the other experiments, stone crabs (Lithodidae), the blue-hake (Antimora rostrata) and amphipods were the primary consumers, but the rate of bait consumption was lower. Patagonian toothfish (D. eleginoides) were attracted to the bait at each experiment, but did not attempt to consume the bait. The patchiness in the fauna may be a result of depth, substratum and topography, but in general the rapid response of the scavenging fauna indicates that carrion is rapidly dispersed, with little impact on the local sediment community.
Dynamics of a subtidal population of the porcellanid crab Pisidia longicornis (Decapoda: Crustacea)
Authors: Robinson M. , Tully O.
Published: July 2002

A subtidal population of the anomuran crab, Pisidia longicornis was sampled quantitatively throughout 1997. Divers, using SCUBA equipment, conducted suction sampling each month, with concentrated effort directed towards the settlement season. Pisidia occurred in very high densities, constituting the major component of decapod community abundance. Gravid females were detected between March and September. Newly settled megalopae were present in benthic samples from June until late September. Six distinct settlement events were detected during this period, with pulses coinciding with low spring tides. Body size at settlement decreased as temperature during larval development increased. The rapid growth of each distinct settlement group was followed over time through each subsequent crab stage up to maximum adult size. Growth was suspended between December and April. Survival within each distinct settlement group was density-independent during the first summer's growth. Mortality increased between June and July settlement events, with the rate of decline remaining a linear function.
The morphology of the pit organs and lateral line canal neuromasts of Mustelus antarcticus (Chondrichthyes: Triakidae)
Authors: Peach Meredith B. , Rouse Gregory W.
Published: July 2002

The pit organs (free neuromasts) of sharks are part of the lateral line sensory system, but there is still confusion about their exact morphology and function(s). This is partly because of reported physiological differences between the pit organs and the lateral line canal neuromasts, and partly because the morphology of pit organs has not been adequately documented. To compare their morphology, the pit organs and canal neuromasts of the gummy shark Mustelus antarcticus (Chondrichthyes: Triakidae) were examined using transmission and scanning electron microscopy. Both pit organs and canal neuromasts had hair cells with the `staircase' arrangement of sensory hairs (stereovilli) characteristic of vertebrate mechanoreceptors. Stereovilli bundles of different sizes were distributed haphazardly throughout the pit organs and canal neuromasts. The density of hair cells was similar in the pit organs and canal neuromasts, but differences in the overall size and/or shape of the sensory epithelia might account for some of the reported differences in mechanosensitivity.
Cloning of a putative voltage-gated sodium channel from
the turbellarian flatworm Bdelloura candida
Authors: JEZIORSKI M. C. , GREENBERG R. M. , ANDERSON P. A. V.
Published: July 2002

The neuromuscular sodium currents of early invertebrates such as
platyhelminths display distinctive kinetic and pharmacological properties.
We have cloned a cDNA from the horseshoe crab flatworm Bdelloura candida
that encodes a
protein homologous to the primary subunit of voltage-gated sodium channels.
The
B. candida protein, named BdNa1,
exhibits amino acid identity of 40–47% to sodium channels of vertebrates
and higher invertebrates. BdNa1 has the
multidomain structure characteristic of sodium channels, and is most
highly conserved in the hydrophobic transmembrane
segments and the regions that form the pore of the channel. Northern blot
analysis confirms the presence of a 5·4 kb
BdNa1 transcript in B. candida tissue. The information provided
by analysis of the BdNa1 sequence offers insight into
the physiology of platyhelminth sodium currents.