bluuebunny/crossref_metadata_2025 huggingface dataset:
YASIN DUTTON, The Origins of Islamic Law: The Qur⊃an, the Muwatta⊃and Madinian⊂Amal (London: Curzon Press, 1999). $80.00 cloth.
Authors: El Fadl Khaled Abou
Published: July 2002

Yasin Dutton makes a significant contribution to our understanding of the juristic activity in early Islam. His book produces a systematic and thorough study of the methodologies and legal techniques of Malik's Muwatta⊃, and in so doing, it sheds important light on the origins of Islamic law. Dutton carefully documents Malik's reliance on the Qur⊃an and the ⊂amal (practice) of the people of Medina in formulating early Islamic legal doctrines. In this context, Dutton challenges much of Western scholarship, which tended to minimize the role of the Qur⊃an and the Prophetic sunna in the development of early Islamic jurisprudence. The Qur⊃an, sunna, and ⊂amal, Dutton argues, formed integral components of early Medinian juristic discourses. Importantly, Dutton calls for a more sophisticated understanding of the concept of ⊂amal. He distinguishes between sunna and ⊂amal and between sunna and hadith. Sunna, Dutton contends, consists of the collective inherited precedent of the Prophet. In many ways, it is the Qur⊃anic precedent as well as the interpretations and ijtih―ad of the Prophet as remembered, in a general sense, by the early Muslim community. ⊂Amal, on the other hand, is the Qur⊃an and sunna in action as well as the interpretations and ijtih―ad of the companions, successors, and successors of the successors. Therefore, in a sense, Dutton argues that all ⊂amal includes the sunna, but not all sunna includes ⊂amal.
ADNAN ABU-ODEH, Jordanians, Palestinians and the Hashemite Kingdom in the Middle East Peace Process (Washington, D.C.: United States Institute of Peace Press, 1999). Pp. 340. $37.50 cloth, $19.95 paper.
Authors: Fischbach Michael R.
Published: July 2002

Few people can speak to the complex issue of Palestinian identity in Jordan with the degree of background of Adnan Abu-Odeh, a West Bank Palestinian who has made his mark in the Jordanian political establishment by serving in the Directorate of General Intelligence (mukhabarat), the royal diwan, the cabinet, the Senate, and Jordan's delegation to the United Nations, and as an adviser to King Hussein and his son King ⊂Abdullah II. Over the course of more than three decades of public service in Jordan, Abu-Odeh has been an inside observer and, at times, a direct participant in many of the major episodes in the Hashemite kingdom's recent history. He has also been a controversial and sometimes outspoken figure for both Palestinians and East Bank (Transjordanian) Jordanians.
THE DECLINE OF THE CAPE GENTRY, 1838–c. 1900
Authors: DOOLING WAYNE
Published: July 2002

The final ending of slavery in 1838 marked a radical break in the agrarian
history of the Cape Colony. The liberated slaves could and did make use of
the mobility that emancipation allowed them. This amounted to a real
negotiation of the price of labour, for at various points in the nineteenth
century the price of labour threatened the very profitability of farming. For
the greater part of the century many landlords were led, in the words of one
colonial official, ‘to look back…with something very like an envious eye, to
the days in which slavery was tolerated by law, because then the slaveholder
could command labour whenever it was needed.’

For the former slaveowners, the outcome was agricultural innovation and
routine insolvency, and merchants came to have an increasingly important
role in the rural political economy. But post-emancipation agrarian structures
were not merely shaped by the incursion of merchant capital and the
mobility of labour. The former slaveholders displayed a remarkable tenacity.
Most significantly, Cape landlords were heirs to a carefully constructed
political economy in which the rules governing the circulation of land and
wealth were clearly defined in community and familial terms and in which
the ties of credit ran both vertically and horizontally. This was a ‘moral
community’ in which all were cushioned against the sometimes detrimental
effects of participation in a market economy. It is for this reason that the
intervention of English-speaking merchants, by not paying due regard to
these rules, was of a qualitatively different kind. Community, in short,
provides the backdrop against which much of the colony's agrarian history
was played out.

This article seeks to provide a rather different interpretation of the post-emancipation Western Cape than is at present on offer.
Genetic diversity in perennial ryegrass
(Lolium perenne) evaluated by hybridization with
ribosomal DNA: implications for cultivar identification and breeding
Authors: WARPEHA K. M. F. , CAPESIUS I. , GILLILAND T. J.
Published: July 2002

To date, little molecular genetic research has been conducted in

Lolium and the current study is the
first investigation of diversity in ribosomal DNA (rDNA) among perennial
ryegrass cultivars.
Ribosomal DNA probes derived from the intergenic spacer (IGS–M)
and transcribed (COD–M)
regions of mustard (Sinapis alba) were used to examine 35
perennial ryegrass (L. perenne L.) cultivars
for genetic diversity using RFLP methodology. Analysis of
digested genomic DNA on Southern blots
revealed only 10 cultivars with unique RFLP patterns. Genetic
diversity was exclusively associated
with the IGS–M probe, as the cultivars were all
indistinguishable when examined with the COD–M
probe. This low incidence of distinctions was not expected, given
that the 35 cultivars were known
genetically distinct entities, representing the very wide range of the
major phenotypic and
physiological characteristics present in commercial stocks.
Furthermore, the forage cultivars were
proportionately less polymorphic in comparison to the amenity
cultivars. This was also unexpected
as amenity cultivars are recognized as a more closely clustered
group than the forage cultivars, based
on morphological characteristics. The potential use of rDNA for
assessing cultivar diversity and
breeding histories in perennial ryegrass is considered.
Effects of termite damage to maize of seed extracts of
Azadirachta indica and Piper guineense in farmers'
fields
Authors: UMEH V. C. , IVBIJARO M. F.
Published: July 2002

The efficacy of insecticides derived from two local plants was tested on termites infesting maize in
maize–cassava–‘Egusi’ melon intercrops in two farmers' fields in south-western Nigeria during the
1989/90 and 1990/91 cropping seasons. The intercrops consisted of 40000, 20000, and 10000 maize
plants/ha, with a fixed population of 10000 plants/ha of both cassava and melon. The insecticides
were aqueous extracts of ripe seeds of neem (Azadirachta indica A. Juss) and the crude seed oil of
Piper guineense Schum And Thonn, each at 10% concentration at the rate of 390 litres/ha and 18
litres/ha, respectively. On the plots treated with these natural insecticides, damage by termites
[Microtermes spp., Macrotermes bellicosus Smeathman = nigeriensis Sjostedt and M. subhyalinus
Rambur (Isoptera: Termitidae)] was significantly lower and maize yields higher than on the control
plots. The mean percentage of maize stems attacked by termites (considering all categories of termite
damage) in untreated plots during the trials ranged between 0–22% in 1989 and 2–46% in 1990.
Planting densities did not significantly influence termite attack on maize. Cassava and melon plants
or cassava tubers were not attacked by termites in any of the trials and their yields were not affected
by insecticide treatments or planting density of maize.
A Kodak Refraction of Henry James's “The Real Thing”
Authors: RAWLINGS PETER
Published: July 2002

Eastman Kodak was in the vanguard of those companies seeking to

capitalize on newly available mass markets at home and abroad in the
1880s and 1890s. George Eastman had acute instincts for photographic
innovation, cost-effective manufacturing, and the assembling of powerful

corporate structures, but his greatest gift was for seizing on, and
fostering, the general demand for a commodity with specious aesthetic
inflections – a simple camera, together with a processing service
available
by mail – at a time when the appetite for such things was becoming

insatiable. As Lawrence W. Levine has argued, photography

was the perfect instrument for a society with a burgeoning middle class,
which
could not satisfy itself with processes and images that had previously
been
confined to elite circles.

The aim of this article is to examine aspects of Henry James's
predicament
within the context of mass photography. In particular, the focus will be

on “The Real Thing” (1893) and its engagement with issues of

representation and reproduction in an arena forever changed by Kodak.
CONSANGUINITY AND ITS RELATIONSHIP TO DIFFERENTIAL FERTILITY AND MORTALITY IN
THE KOTIA: A TRIBAL POPULATION OF ANDHRA PRADESH, INDIA
Authors: NAIDU YASMIN, J. M. , MASCIE-TAYLOR C. G. N.
Published: July 2002

Data on patterns of marriage, differential fertility and mortality
were collected from 211 Kotia women residing in Visakhapatnam district of
Andhra Pradesh, India. Consanguineous marriages made up just over a quarter of
the total, and of these, father's sister's daughter (FSD) were more common
than mother's brother's daughter (MBD). The mean inbreeding coefficient for
the sample (F) was 0·0172. Women in consanguineous marriages had a lower mean
number of total conceptions, live births and living offspring (net fertility)
than women in non-consanguineous marriages. Significant heterogeneity was
found in the means of living offspring for FSD, MBD and non-consanguineous
couples, but not for
conceptions and live births.
Thermal inactivation kinetics of bovine cathepsin D
Authors: HAYES MAURICE G. , HURLEY MICHAEL J. , LARSEN LOTTE B. , HEEGAARD CHRISTIAN W. , MAGBOUL ABDALLAH A. A. , OLIVEIRA JORGE C. , McSWEENEY PAUL L. H. , KELLY ALAN L.
Published: July 2002

Cathepsin D, the principal indigenous acid proteinase in bovine milk, is a lysosomal proteinase, which exists in milk in four forms, including the inactive zymogen procathepsin D. The thermal inactivation kinetics of bovine cathepsin D, isolated from spleen and milk, were studied under isothermal conditions, using a specific HPLC assay to determine residual activity. Inactivation of the blood enzyme preparation followed first order kinetics, with z-values in phosphate buffer (pH 6·7) and skimmed milk of 6·5 and 7·6 °C, respectively, the enzyme being far more stable in the latter environment. Inactivation kinetics of the enzyme purified from milk were more complex, and could be best approximated by a double exponential model. Again, stability was higher in milk than in buffer. The double exponential model may indicate differing heat stabilities of isoforms of the enzyme, or stabilization of the enzyme by some milk constituent. It is clear that the enzyme can survive, at least partially, processes such as heating at 55 °C for 30 min during manufacture of high-cook cheese varieties (45% survival), and HTST pasteurization (8% survival), and thus may contribute to proteolysis in a range of dairy products.
Differential titration of plasmin and plasminogen in milk using
sandwich ELISA with monoclonal antibodies
Authors: DUPONT DIDIER , BAILLY CHRISTELLE , GROSCLAUDE JEANNE , COLLIN JEAN-CLAUDE
Published: July 2002

Two sandwich enzyme-linked immunosorbent assays (ELISA) have been

developed for quantitation of bovine milk plasminogen and plasmin. The
assays used
two monoclonal antibodies, one specific for plasminogen and the other specific
for
plasminogen plus plasmin. Plasmin concentration was obtained by subtracting
the
first concentration from the second. The assays were sensitive (linear
range,
5–75 ng/ml), repeatable (CV, 8 and 5% for plasmin
and plasminogen titration
respectively), specific (no cross reactivity with the major milk
proteins) and directly
applicable to skimmed milk with no particular pretreatment of the sample.
However,
ELISA did not permit complete titration of milk plasminogen and plasmin
(only
60–90% could be quantified). This lack of accuracy was due to
casein interfering with
the plasmin–plasminogen titration by ELISA. Results obtained with
ELISA or an
enzymic technique on 20 milk samples collected from individual cows milked

throughout pregnancy showed that the ELISA was particularly suitable for
analysis
of late lactation or mastitic milk where proteinase inhibitors
interfered with enzymic quantitation.
Cortisol, parathyroid hormone-related protein and the onset of
calcium secretion by the mammary gland of the goat
Authors: THOMPSON GORDON E. , ABBAS S. KHAWAR , HOLT CARL , CARE ANTHONY D.
Published: July 2002

During lactogenesis in the goat, the onset of secretion of calcium

into milk occurs
at parturition (Thompson et al. 1995) at approximately the same
time
as the onset
of secretion of parathyroid hormone-related protein (PTHrP) by the mammary

gland (Ratcliffe et al. 1992); these events may be unrelated or
PTHrP
may be involved in calcium transport from blood to milk.

Parturition in goats is initiated by fetal secretion of cortisol (Flint

et al. 1978) and
maternal secretion of cortisol also increases (Paterson &
Linzell, 1971). Injecting
cortisol locally into the sinus of a mammary gland of the late-pregnant
goat when the
tight junctions between secretory epithelial cells appear to be
‘loose’, and injectate
can reach the basolateral surfaces of secretory cells, stimulates an early

tightening of
these junctions (Thompson, 1996) as occurs naturally at parturition. This
tightening
can be produced by an increased concentration of ionized calcium in the
extracellular
fluid of the gland (Neville & Peaker, 1981).

The experiments reported here were undertaken to determine if cortisol
injection
stimulates the mammary gland to secrete both PTHrP and calcium before
parturition.
Numerical study of internal wave–caustic and
internal wave–shear interactions in a stratified fluid
Authors: JAVAM A. , IMBERGER J. , ARMFIELD S. W.
Published: July 2002

The behaviour of internal waves at a caustic level, turning point and critical layer have
been investigated numerically. At a caustic reflection, a triad interaction was formed
within the reflection region and the internal wave energy was transferred to lower
frequencies (subharmonics). This resulted in a local subharmonic instability. One of
the excited internal waves penetrated the caustic level and propagated downwards.
This downward propagating wave then produced a second caustic where further
reflection could take place. At a turning point, nonlinear interaction between the
incident and reflected waves transferred energy to higher frequencies (evanescent
trapped waves) which resulted in a superharmonic instability. At the critical level,
energy was transferred to the mean flow. As the degree of nonlinearity increased,
more energy was found to be transferred and overturning resulted due to a shear
instability.
Active control of near-wall turbulence by local oscillating blowing
Authors: TARDU SEDAT F.
Published: July 2002

The effect of time-periodical blowing through a spanwise slot on the near-wall
turbulence characteristics is investigated. The blowing velocity changes in a cyclic
manner from 0 to 5 wall units. The frequency of the oscillations is nearly equal
to the median frequency of the near-wall turbulence. The measurements of the
wall shear stress and the streamwise velocity are reported and discussed. The flow
field near the blowing slot is partly relaminarized during the acceleration phase
of the injection velocity which extends 40 wall units downstream. The imposed
unsteadiness is confined to the buffer layer, and the time-mean structural parameters
under unsteady blowing are found to be close to those of isotropic turbulence in this
region. The relaminarized phase is unstable and gives way to a coherent spanwise
structure that increases the shear from 80 to 300 wall units downstream of the slot in
a predictable way. This phenomenon is strongly imposed-frequency dependent.
Numerical studies of singularity formation at free surfaces and
fluid interfaces in two-dimensional Stokes flow
Authors: POZRIKIDIS C.
Published: July 2002

We consider the analytic structure of interfaces in several
families of steady and unsteady two-dimensional Stokes flows, focusing
on the formation of corners and cusps. Previous experimental and
theoretical studies have suggested that, without surface tension, the
interfaces spontaneously develop such singular points. We investigate
whether and how corners and cusps actually develop in a time-dependent
flow, and assess the stability of stationary cusped shapes predicted by
previous authors. The motion of the interfaces is computed with high
resolution using a boundary integral method for three families of
flows. In the case of a bubble that is subjected to the family of
straining flows devised by Antanovskii, we find that a stationary
cusped shape is not likely to occur as the asymptotic limit of a
transient deformation. Instead, the pointed ends of the bubble
disintegrate in a process that is reminiscent of tip streaming. In the
case of the flow due to an array of point-source dipoles immersed
beneath a free surface, which is the periodic version of a flow
proposed by Jeong & Moffatt, we find evidence that a cusped shape
indeed arises as the result of a transient deformation. In the third
part of the numerical study, we show that, under certain conditions,
the free surface of a liquid film that is levelling under the action of
gravity on a horizontal or slightly inclined surface develops an
evolving corner or cusp. In certain cases, the film engulfs a small air
bubble of ambient fluid to obtain a composite shape. The structure of a
corner or a cusp in an unsteady flow does not have a unique shape, as
it does at steady state. In all cases, a small amount of surface
tension is able to prevent the formation of a singularity, but
replacing the inviscid gas with a viscous liquid does not have a
smoothing effect. The ability of the thin-film lubrication equation to
produce mathematical singularities at the free surface of a levelling
film is also discussed.
Structure and energetics of optimal Ekman layer

perturbations
Authors: FOSTER RALPH C.
Published: July 2002

The optimal non-modal perturbations for the neutrally

stratified boundary layer in a

rotating frame of reference (Ekman layer) are found for a Reynolds

number characteristic of the planetary boundary layer (PBL). Two classes

of non-modal instabilities are found: evanescent perturbations,

with lifetimes up to about one hour,

and growing instabilities. The important difference between these

types of perturbations is whether or not the optimal non-modal

perturbation projects onto an unstable normal mode. The

evanescent instabilities are of smaller scale and are

oriented at larger angles to the surface isobars compared to

either the growing perturbations or normal-mode instabilities.

The optimal perturbations take the form of vortices at an acute

angle to the geostrophic flow that rapidly transform

into streaks with associated overturning motion. The energetics

of the optimal perturbations are investigated in detail to

clarify the instability mechanism throughout its evolution.

Nonlinear stability analyses of the neutrally stratified Ekman

layer have shown that the normal-mode instability will equilibrate

with the mean flow to form boundary-layer-scale equilibrium roll

eddies aligned closely with the geostrophic flow. However,

numerical simulations do not generate these rolls in neutral

stratification although they often realize small-scale

near-surface streaks oriented at large angles to the geostrophic

wind. The evanescent optimal perturbations bear a close

resemblance to the simulated streaks. It is proposed that

the non-model perturbation mechanism is associated with

the streaks.
Effect of slight stratification on the nonlinear spatial
evolution of a weakly unstable wave in a free shear layer
Authors: SHUKHMAN I. G. , CHURILOV S. M.
Published: July 2002

We examine the spatial evolution of an instability wave excited
by an external source
in a free, nearly non-dissipative, stably stratified shear flow
with a small Richardson
number Ri[Lt ]1. It turns out that at the nonlinear stage
of evolution even so small
a stratification modifies greatly the evolution behaviour
compared with the case of a
homogeneous flow which was studied in detail by Goldstein & Hultgren (1988).

We have investigated (analytically and numerically) different stages of evolution
corresponding to different critical layer regimes, and determined the formation
conditions and structure of a quasi-steady nonlinear critical layer.

It is shown that the stratification influence upon the nonlinear evolution
is governed by the parameter
(Pr−1)Ri/γ2L,
where Pr is the Prandtl number and γL is the wave's
linear growth rate (which is a measure of supercriticality), and this effect
is important only when γL<Ri1/2,
Pr≠1. The character of this influence radically depends on
the sign of (Pr−1). Thus, when Pr<1 the amplitude
in the course of the evolution
varies in a limited range and either reaches saturation, when the supercriticality
is small enough or, at higher supercriticality, performs quasi-periodic oscillations,
whose structure becomes increasingly complicated with increasing
γL. When Pr>1
stratification leads to the appearance of new evolutionary stages, namely the stage
of explosive growth in the unsteady critical layer regime,
and the stage of essentially
unsteady evolution in the nonlinear critical layer regime, and
to a modification of the
power-law growth in the regime of a quasi-steady nonlinear critical layer.
Vorticity, strain-rate and dissipation characteristics

in the near-wall region of turbulent boundary layers
Authors: HONKAN ANANT , ANDREOPOULOS YIANNIS
Published: July 2002

Experimental results are presented that reveal the structure of

a two-dimensional

turbulent boundary layer which has been investigated by measuring the time-dependent

vorticity flux at the wall, vorticity vector, strain-rate tensor and

dissipation-rate tensor in the near-wall region with spatial resolution
of the

order of 7 Kolmogorov

viscous length scales. Considerations of the structure function of velocity

and pressure, which constitute vorticity flux and vorticity, indicated
that, in the

limit of vanishing

distance, the maximum attainable content of these quantities which corresponds
to

unrestricted resolution, is determined by Taylor's microscale.

They also indicated that

most of the contributions to vorticity or vorticity flux come from the

uncorrelated part

of the two signals involved. The measurements allowed the computation of
all

components of the vorticity stretching vector, which indicates the rate
of change of

vorticity on a Lagrangian reference frame if viscous effects are

negligible, and several

matrix invariants of the velocity gradient or strain-rate tensor and

terms appearing in the transport equations of vorticity, strain rate and

their squared fluctuations. The

orientation of vorticity revealed several preferential directions. During
bursts or

sweeps vorticity is inclined at 35° to the longitudinal direction.

It was also found that

there is high probability of the vorticity vector aligning with the direction
of the

intermediate extensive strain corresponding to the middle eigenvector

of the strain-rate

matrix. The results of the joint probability distributions of the vorticity
vector

orientation angles showed that these angles may be related to

those of hairpin vortex

structures. All invariants considered exhibit a very strong intermittent

behaviour which

is characterized by large-amplitude bursts which may be of the order of
10 r.m.s.

values. Small-scale motions dominated by high rates of turbulent kinetic
energy

dissipation and high enstrophy density are of particular interest.

It appears that the

fluctuating strain field dominates the fluctuations of pressure more than
enstrophy.

Local high values of the invariants are also often associated with peaks
in the shear

stress.
Free boundary effects on baroclinic instability
Authors: BERON-VERA F. J. , RIPA P.
Published: July 2002

The effects of a free boundary on the stability of a baroclinic

parallel flow are

investigated using a reduced-gravity model. The basic state has uniform
density

stratification and a parallel flow with uniform vertical shear

in thermal-wind balance

with the horizontal buoyancy gradient. A finite value of the velocity

at the free (lower)

boundary requires the interface to have a uniform slope in the direction
transversal

to that of the flow. Normal-mode perturbations with arbitrary vertical
structure are

studied in the limit of small Rossby number. This solution is restricted
to neither a

horizontal lower boundary nor a weak stratification in the basic state.

In the limit of a very weak stratification and bottom

slope there is a large separation

between the first two deformation radii and hence short or long perturbations
may

be identified:

(a) The short-perturbation limit corresponds to the

well-known Eady problem in

which case the layer bottom is effectively rigid and its slope in the basic
state is

immaterial.

(b) In the long-perturbation limit the bottom is free

to deform and the unstable

wave solutions, which appear for any value of the Richardson number

Ri, are

sensible to its slope in the basic state. In fact, a sloped bottom

is found to stabilize the basic flow.

At stronger stratifications there is no distinction between

short and long perturbations, and the bottom always behaves as a free

boundary. Unstable wave solutions are found for Ri→∞

(unlike the case of long perturbations). The increase in stratification
is

found to stabilize the basic flow. At the maximum stratification compatible

with static stability, the perturbation has a vanishing growth rate

at all wavenumbers.

Results in the long-perturbation limit corroborate those predicted

by an approximate layer model that restricts the buoyancy

perturbations to have a linear vertical

structure. The approximate model is less successful in the short-perturbation
limit

since the constraint to a linear density profile does not

allow the correct representation of the exponential trapping of

the exact eigensolutions. With strong stratification,

only the growth rate of long enough perturbations superimposed on basic
states with

gently sloped lower boundaries behaves similarly to that of the exact model.
However,

the stabilizing tendency on the basic flow as the stratification

reaches its maximum is

also found in the approximate model. Its partial success in this case

is also attributed

to the limited vertical structure allowed by the model.
Numerical studies of cusp formation at fluid interfaces in Stokes
flow
Authors: POZRIKIDIS C.
Published: July 2002

Numerical studies are performed addressing the development of regions
of high
curvature and the spontaneous occurrence of cusped interfacial shapes in
two-dimensional
and axisymmetric Stokes flow. In the numerical simulations, the velocity

field is computed using a boundary-integral method, and the evolution of
the
concentration of an insoluble surfactant over an evolving interface is
computed using
an implicit finite-volume method. Three configurations are considered in
detail, and the
results are used to elucidate three different aspects of cusp formation.
In the first series,
the deformation of a two-dimensional bubble immersed in a family of straining
flows
devised by Antanovskii, and of an axisymmetric bubble immersed in an analogous

family of flows devised by Sherwood, are examined. The numerical results
indicate that
highly elongated and cusped two-dimensional shapes, and pointed or cusped

axisymmetric shapes, are unstable and should not be expected to occur in
practice. In
the second series of studies, the role of an insoluble surfactant on the
transient
deformation of bubbles subject to the Antanovskii or Sherwood flow is investigated.

Under certain conditions, the reduced surface tension at the tips raises
the local
curvature to high values and causes the ejection of a sheet or column of
gas by means
of tip streaming. In the third series of studies, the coalescence of a
polygonal formation
of five viscous columns of a fluid placed in an arrangement that differs
only slightly
from one proposed recently by Richardson is examined. The numerical results
confirm
Richardson's predictions that transient cusps may occur at a finite
time in the presence
of surface tension. The underlying physical mechanism is discussed on the
basis of
reversibility of surface-driven Stokes flow and with reference to the regularity
of the
motion driven by negative surface tension. Replacing the inviscid ambient
gas with a
slightly viscous fluid whose viscosity is as low as one hundredth the viscosity
of the
cylinders suppresses the cusp formation.
On the complete radiation-diffraction problem
and wave-drift damping of marine bodies in the yaw mode of motion
Authors: FINNE STYRK , GRUE JOHN
Published: July 2002

The coupled radiation-diffraction problem due to a floating
body with slow
(time-dependent) rotation about the vertical axis in incoming waves is
studied by means
of potential theory. The water depth may be finite. First, the radiation
problem is
described. It is shown how the various components of the velocity potential
may
be obtained by means of integral equations. The first-order forces in the
coupled
radiation-diffraction problem are then considered. Generalized Haskind
relations for
the exciting forces and generalized Timman–Newman relations for the
added mass
and damping forces are deduced for bodies of arbitrary shape with vertical
walls
at the water line. The equation of motion is obtained, and the frequencies
of the
linear body responses superposed on the slow rotation are identified. Formulae
for
the wave-drift damping coefficients in the yaw mode of motion are derived
in explicit
form, and the energy equation is discussed. Computations illustrating the
various
aspects of the method are performed for two ships. The wave-drift damping
moment
is found to become positive in the present examples. When the rotation
axis is moved
far away from the body, the slow motion becomes effectively unidirectional,
and
results of the translational case are recovered.
Turbulent fountains in a stratified fluid
Authors: BLOOMFIELD LYNN J. , KERR ROSS C.
Published: July 2002

The turbulent fountain that results from the injection of a dense
fluid upwards into
a large tank of stably stratified fluid of lower density is studied experimentally
and
theoretically. For both axisymmetric and line fountains, we have used a
combination
of dimensional arguments and laboratory experiments to determine the initial
height
above the source at which the flow first comes to rest. Depending on the
strength
of the stratification and the fluxes of momentum and buoyancy at the source,
the
subsequent down flow may either spread along the base of the tank or intrude
at an
intermediate height in the environment. We determine both the height of
intermediate
intrusion and the critical condition for spreading along the base. We also
relate
numerical solutions of the entrainment equations to our experimental observations,

and obtain effective entrainment coefficients for both axisymmetric and
line fountains.
Finally, we discuss the quantitative application of our results to the
replenishment of
magma chambers and to the heating or cooling of a room.
The background flow method. Part 2.
Asymptotic theory of dissipation bounds
Authors: NICODEMUS ROLF , GROSSMANN S. , HOLTHAUS M.
Published: July 2002

We study analytically the asymptotics of the upper bound on energy
dissipation for
the two-dimensional plane Couette flow considered numerically in Part 1
of this work,
in order to identify the mechanisms underlying the variational approach.
With the
help of shape functions that specify the variational profiles either in
the interior or
in the boundary layers, it becomes possible to quantitatively explain all
numerically
observed features, from the occurrence of two branches of minimizing wavenumbers

to the asymptotic parameter scaling with the Reynolds number. In addition,
we derive
a new variational principle for the asymptotic bound on the dissipation
rate. The
analysis of this principle reveals that the best possible bound can only
be attained
if the variational profiles allow the shape of the boundary layers to change
with
increasing Reynolds number.
The spiral wind-up of vorticity in an inviscid planar vortex
Authors: BASSOM ANDREW P. , GILBERT ANDREW D.
Published: July 2002

The relaxation of a smooth two-dimensional vortex to axisymmetry,
also known as
‘axisymmetrization’, is studied asymptotically and numerically.

The vortex is perturbed
at t=0 and differential rotation leads to the wind-up of
vorticity fluctuations to form
a spiral. It is shown that for infinite Reynolds number and in the linear
approximation,
the vorticity distribution tends to axisymmetry in a weak or coarse-grained
sense:
when the vorticity field is integrated against a smooth test function the
result decays
asymptotically as t−λ with
λ=1+(n2+8)1/2,
where n is the azimuthal wavenumber
of the perturbation and n[ges ]1. The far-field stream function
of the perturbation
decays with the same exponent. To obtain these results the paper develops
a complete
asymptotic picture of the linear evolution of vorticity
fluctuations for large times t,
which is based on that of Lundgren (1982).
Turbulent velocity fluctuations need not be Gaussian
Authors: JIMÉNEZ JAVIER
Published: July 2002

It is noted that the central limit theorem does not constrain
the probability distribution
of the components of the turbulent velocity fluctuations to be Gaussian,
if their
spectral slope is steeper than k−1. It is shown
that, in a
model of homogeneous turbulence in which each wavenumber of the energy
spectrum
predominantly receives contributions from eddies with roughly homogeneous
amplitudes
and coherence lengths, the p.d.f. would be slightly sub-Gaussian. This
agrees with
the available experimental evidence.
Oscillatory flow states in an enclosed cylinder
with a rotating endwall
Authors: STEVENS J. L. , LOPEZ J. M. , CANTWELL B. J.
Published: July 2002

A combined experimental and numerical investigation is presented of the multiple
oscillatory states that exist in the flows produced in a completely filled, enclosed,
circular cylinder driven by the constant rotation of one of its endwalls. The flow
in a cylinder of height to radius ratio 2.5 is interrogated experimentally using flow
visualization and digitized images to extract quantitative temporal information. Numerical
solutions of the axisymmetric Navier–Stokes equations are used to study the
same flow over a range of Reynolds numbers where the flow is observed to remain
axisymmetric. Three oscillatory states have been identified, two of them are periodic
and the third is quasi-periodic with a modulation frequency much smaller than the
base frequency. The range of Reynolds numbers for which the quasi-periodic flow
exists brackets the switch between the two periodic states. The results from the combined
experimental and numerical study agree both qualitatively and quantitatively,
providing unambiguous evidence of the existence and robustness of these multiple
time-dependent states.
Double-diffusive instabilities in a vertical slot
Authors: KERR OLIVER S. , TANG KIT YEE
Published: July 2002

A fluid stably stratified by a salinity gradient and enclosed between two vertical
boundaries can become unstable when it is subjected to a temperature difference
between the walls. The linear stability of such a fluid in a vertical slot is investigated.
Errors in earlier results are found, confirming recent results of Young & Rosner
(1998). Four different asymptotic regimes on the stability boundary are identified.
One of these, the limit of a strong salinity gradient, has previously been analysed. The
analyses of the separate asymptotic limits of weak salinity gradient, large temperature
difference and small wavenumber are also given. These four cases make up much of
the total boundary between stability and instability for double-diffusive instabilities in
a vertical slot, and so most of this boundary can be mapped out for general Prandtl
numbers and salt/heat diffusivity ratios using these results.
V-waves, bow shocks, and wakes in supercritical hydrostatic flow
Authors: JIANG QINGFANG , SMITH RONALD B.
Published: July 2002

The structure of the bow shock, V-wave, and the related wave drag and wake in
supercritical ambient flow are investigated for homogeneous hydrostatic single-layer
flow with a free surface over an isolated two-dimensional (i.e. h(x, y)) obstacle. The
two control parameters for this physical system are the ratio of obstacle height to
fluid depth and the Froude number F = U/√gH. Based on theoretical analysis and
numerical modelling, a steady-state regime diagram is constructed for supercritical
flow. This study suggests that supercritical flow may have an upstream bow shock
with a transition from the supercritical state to the subcritical state near the centreline,
and a V-shock in the lee without a state transition. Unlike subcritical flow, neither
a flank shock nor a normal lee shock is observed, due to the local supercritical
environment. Both the bow shock and V-shock are dissipative and reduce the Bernoulli
constant, but the vorticity generation is very weak in comparison with subcritical
ambient flow. Thus, in supercritical flow, wakes are weak and eddy shedding is
absent.

Formulae for V-wave shape and V-wave drag are given using linear theory. Both
formulae compare well with numerical model runs for small obstacles.

These results can be applied to air flow over mountains, river hydraulics and coastal
ocean currents with bottom topographies.
The Rate of Growth of Productivity in
Mexico, 1850–1933: Evidence from the
Cotton Textile Industry
Authors: RAZO ARMANDO , HABER STEPHEN
Published: July 2002

This article employs previously unused data sources and techniques
in
order to estimate labour productivity and total factor productivity in
the Mexican
cotton textile industry over the period 1850–1933. Our findings indicate:
(1)
substantial productivity growth prior to the Porfiriato; (2) rapid productivity

growth throughout the Porfiriato; (3) a swift, though incomplete, recovery
from
the Revolution during the 1920s; and, (4) an insignificant impact on productivity

from the Great Depression. We also find evidence that the large, joint
stock,
limited liability firms that were founded during the Porfiriato had higher
levels
of total factor productivity than privately owned firms, but only for a
short
period of time, which suggests that these firms might have been sub-optimally

large. Our results also indicate that labour markets in Porfirian Mexico
were
efficient. This suggests that manufacturers may not have had the monopsony

power in labour markets that the literature indicates.
Trade Reform and Manufacturing
Performance in Mexico: from import
substitution to dramatic export growth
Authors: WEISS JOHN
Published: July 2002

Since the trade liberalisation of the mid 1980s the trade regime
facing
Mexican manufacturers has changed dramatically. The economy has moved from

one where import substitution behind tariffs and some licensing restrictions

was the norm to a highly open trading environment with virtual free trade

between Mexico and its largest trade partner the USA and modest tariffs
of
around 10 per cent with other countries. Since the late 1980s manufactured

exports have grown dramatically at one of the fastest rates of any economy,

although financed by large capital inflows the net trade balance in manufactures

remains negative. This paper surveys the recent evidence on the impact
of this
liberalisation process on manufacturing performance. Various performance

indicators can be used to assess the impact on manufacturing. Here four
are
discussed: (1) revealed comparative advantage measures of net trade balance;
(2)
efficiency wage estimates of unit labour costs; (3) total factor growth;
(4) export
growth. The performance of different branches of manufacturing is examined

using these indicators and tests are conducted to establish links between

movements in these indicators and the degree of exposure to foreign competition

experienced by the various branches. The general conclusion is that the
evidence
is ambiguous with only some studies supporting the view that the greater
the
trade liberalisation in a branch the greater will be the subsequent improvement

in performance.
The Dynamics of Aymara Duality: Change and Continuity in
Sociopolitical Structures in the Bolivian Andes
Authors: ASTVALDSSON ASTVALDUR
Published: July 2002

One of the most persistent and influential concepts in Andean studies
during the last few decades has been that of dualism at different levels of Andean
cultural and sociopolitical life. How dualism works and the manner in which it has
evolved have been the subject of much debate. Within this context, Jesús de
Machaqa in highland Bolivia has been recognised as a region of primary
importance for investigation, because of its enduring socio-political structures.
However, a study of its ‘traditional’ structure carried out in the 1970s showed
that important changes had taken place. New studies of intra-communal
structures and recent studies of Aymara spatial organisation, together with
information held in colonial documents and oral traditions help to shed more
light on the question of dualism. Drawing on all these sources, this article aims
to contribute to wider debate by examining key aspects of the ‘traditional’
structure and setting out some of the methodological problems faced by those
who seek to reconstruct the past of indigenous communities, in particular
problems related to the combined use of colonial documents and oral traditions.
REVIEW ARTICLE Multiple paths towards Universal Grammar
Authors: ROUVERET ALAIN
Published: July 2002

Guglielmo Cinque, Jan Koster, Jean-Yves Pollock, Luigi Rizzi

& Raffaella Zanuttini (eds.), Paths towards Universal Grammar:

studies in honor of Richard S. Kayne. Washington, D.C.: Georgetown

University Press, 1994. Pp. xvi+491.
On the MHD analogue of the Brunt/Väisälä frequency in a magnetized plasma
Authors: ERSHKOVICH ALEXANDER I. , ISRAELEVICH PETER L.
Published: July 2002

The MHD analogue of the Brunt/Väisälä frequency, NB, in a magnetized,
ideally conducting plasma is obtained, with the vertical component of the
magnetic field, Br, taken into account. The magnetic field vector
(Br, Bθ, Bϕ) is assumed to satisfy the
condition B·∇B ≈ BrdB/dr,
which holds in many cases of interest. The frequency NB happens to depend, generally speaking, on the magnetic
field orientation relative to the direction of gravity. However, for an isentropic
gas, the convective instability criterion is governed by the magnetic field strength
(rather than by the orientation of B). In general, the magnetic field has a stabilizing
(destabilizing) effect if B/ρ grows (decreases) along the vertical axis r. This
conclusion seems not to depend on the specific magnetic field configuration.
Tripolar shear-Alfvén vortex structures
Authors: JOVANOVIĆ D. , PEGORARO F. , RASMUSSEN J. JUUL
Published: July 2002

Nonlinear structures in the formof coherent tripolar vortices,
associated with
shear-Alfvén perturbations in the presence of both magnetic and
velocity shears, are
studied analytically.
Elastic electron–ion collisions in a Lorentzian plasma
Authors: JUNG YOUNG-DAE , HONG WOOPYO
Published: July 2002

Plasma screening effects on elastic electron–ion collision processes in
a Lorentzian (kappa)-distribution plasma are investigated using the eikonal
method. The electron–ion interaction potential is obtained by introducing a
plasma dielectric function εκ. The semiclassical straight-line trajectory method
is applied to the path of a projectile electron in order to investigate the
variation of the eikonal phase as a function of impact parameter and spectral
index κ. In the first-order eikonal approximation, the dynamic plasma screening
effect on the eikonal phase is found to be a static screening effect, and depends
only on the Debye length and spectral index. The position of the maximum of
the differential elastic eikonal cross-section recedes from the ion core with
increasing spectral index. The plasma screening effect on the eikonal cross-section increases with decreasing spectral index.
On a saddled snake eel Pisodonophis semicinctus (Osteichthyes: Ophichthidae) trawled in the Strait of Sicily (Mediterranean Sea)
Authors: Ragonese Sergio , Giusto Giovan Battista
Published: July 2002

The occurrence in the Strait of Sicily of the saddled snake eel, Pisodonophis semicinctus (Osteichthyes: Ophichthidae), a rare finding for the Mediterranean Sea, is confirmed on the basis of one specimen caught off the northern coast of Tunisia in 1991. The specimen, 800 mm in total length and 457 g in body weight (preserved condition), was captured during a commercial bottom trawl hauled at 30 m next to Cape Bon (north of Tunisia). This represents the second and fourth documented record of this Atlantic intruder within the Strait of Sicily and the Mediterranean Sea, respectively.
Experimental study on substratum preferences of early juvenile shanny, Lipophrys pholis (Pisces: Blenniidae)
Authors: Almada Vitor , Faria Cláudia
Published: July 2002

Substratum choice tests conducted on early juveniles of Lipophrys pholis show that they clearly prefer rocky to sandy substrata. The cues involved are still unknown. It is likely that this early preference for the habitat of the adults affords them a greater protection from both predators and wave action. At this early stage agonistic behaviour, although in simple forms, is already present and may play a role in competition for the best shelters.
Suppression of mitogen-induced IL-2Rα expression in PBL by serum
from microfilaraemic rats chronically infected with Brugia pahangi
Authors: SATOH M. , TSUKIDATE S. , EISHI Y. , TAMURA N. , YAMAMOTO K. , FUJITA K.
Published: July 2002

To study immunological responses in filarial infections, interleukin-2
receptor α (IL-2Rα) expression in the peripheral blood lymphocytes
(PBL) of Lewis rats infected with Brugia pahangi was observed
by flow cytometry. During infection, no increase in IL-2Rα was observed
in either microfilaraemic or amicrofilaraemic rats. The PBL of rats were
stimulated with phytohaemagglutinin (PHA) and the frequency of IL-2Rα-positivity
was examined. After microfilariae appeared, the increase in the rate of
IL-2Rα-positivity in microfilaraemic rats was less than in amicrofilaraemic
rats. The anergy of IL-2Rα expression in microfilaraemic rats was
restored when their lymphocytes were cultured with normal rat serum. IL-2Rα
expression in normal uninfected rats decreased when cultured with serum
from microfilaraemic rats. These results suggest that microfilariae-related
factors in rat serum suppress PHA-induced IL-2Rα expression in PBL
and thus inhibit cell proliferation and host immunity.
Occurrence of Leishmania major in sandfly urine
Authors: SÁDLOVÁ J. , VOLF P.
Published: July 2002

Promastigotes of Leishmania major were frequently detected in the urine droplets discharged by infected Phlebotomus
papatasi and P. duboscqi females during feeding. Parasites were present in the urine of 37·5% P. papatasi and 16·1% P.
duboscqi females, even in those with low intensity gut infections. Free-swimming forms (elongated nectomonads, short
slender promastigotes and metacyclic forms) predominated in excreted droplets. Viability of excreted parasites was proved
by cultivation on blood agar, and the presence of metacyclic forms in urine droplets was confirmed by specific fluorescence
assay with 3F12 antibodies. While the release of promatigotes from the anus of the sandfly was frequent, these were rarely
egested from the mouth-parts of sandfly females (1·3% for P. duboscqi and 0% for P. papatasi) fed on microcapillaries,
even if the females were heavily infected. The possible role and significance of the discharge of parasites in sandfly urine
are discussed.
That Useless Time Machine
Authors: Casati Robert , Varzi Achille C.
Published: July 2002

Dear ‘Time Machine’ Research Group; if in order to travel to the past one has to have been there already, and if one can only do what has already been done, then why build a time machine in the first place? À quoi bon l'effort?