bluuebunny/crossref_metadata_2025 huggingface dataset:
A secreted Ustilago maydis effector promotes virulence by targeting anthocyanin biosynthesis in maize
Authors: Tanaka Shigeyuki , Brefort Thomas , Neidig Nina , Djamei Armin , Kahnt Jörg , Vermerris Wilfred , Koenig Stefanie , Feussner Kirstin , Feussner Ivo , Kahmann Regine
Published: January 2014

The biotrophic fungus Ustilago maydis causes smut disease in maize with characteristic tumor formation and anthocyanin induction. Here, we show that anthocyanin biosynthesis is induced by the virulence promoting secreted effector protein Tin2. Tin2 protein functions inside plant cells where it interacts with maize protein kinase ZmTTK1. Tin2 masks a ubiquitin–proteasome degradation motif in ZmTTK1, thus stabilizing the active kinase. Active ZmTTK1 controls activation of genes in the anthocyanin biosynthesis pathway. Without Tin2, enhanced lignin biosynthesis is observed in infected tissue and vascular bundles show strong lignification. This is presumably limiting access of fungal hyphae to nutrients needed for massive proliferation. Consistent with this assertion, we observe that maize brown midrib mutants affected in lignin biosynthesis are hypersensitive to U. maydis infection. We speculate that Tin2 rewires metabolites into the anthocyanin pathway to lower their availability for other defense responses.
Cell type-specific and time-dependent light exposure contribute to silencing in neurons expressing Channelrhodopsin-2
Authors: Herman Alexander M , Huang Longwen , Murphey Dona K , Garcia Isabella , Arenkiel Benjamin R
Published: January 2014

Channelrhodopsin-2 (ChR2) has quickly gained popularity as a powerful tool for eliciting genetically targeted neuronal activation. However, little has been reported on the response kinetics of optogenetic stimulation across different neuronal subtypes. With excess stimulation, neurons can be driven into depolarization block, a state where they cease to fire action potentials. Herein, we demonstrate that light-induced depolarization block in neurons expressing ChR2 poses experimental challenges for stable activation of specific cell types and may confound interpretation of experiments when ‘activated’ neurons are in fact being functionally silenced. We show both ex vivo and in vivo that certain neuronal subtypes targeted for ChR2 expression become increasingly susceptible to depolarization block as the duration of light pulses are increased. We find that interneuron populations have a greater susceptibility to this effect than principal excitatory neurons, which are more resistant to light-induced depolarization block. Our results highlight the need to empirically determine the photo-response properties of targeted neurons when using ChR2, particularly in studies designed to elicit complex circuit responses in vivo where neuronal activity will not be recorded simultaneous to light stimulation.
Watching single molecules in action
Authors: Monnet Jordan , Strick Terence R
Published: January 2014

A fluorescent imaging technique called fastFISH has been used to track the various steps involved in the transcription of a single DNA molecule.
Synchrotron Radiation Irradiation Effects for S i Hnon Si(100) Surface in the Synchrotron Radiation Stimulated Si Gas Source Molecular Beam Epitaxy
Authors: Yoshigoe Akitaka , Nagasono Mitsuru , Mase Kazuhiko , Urisu Tsuneo
Published: January 2014

SiHnon Si (100) surfaces during synchrotron radiation (SR) stimulated gas source molecular beam epitaxy (SR-GSMBE) using Si2H6gas (1.0×10-3Torr) are investigatedin situby means of infrared reflection absorption spectroscopy using CoSi2buried metal layer substrates (BML-IRAS) in the low substrate temperature region (400° C-140° C). It has been found that SiH2and SiH3on the surface are easily decomposed by SR to SiH and the decomposition rate of SiH is extremely slow. The decomposition reaction cross sections for SiH2and SiH3for the total irradiating photon flux have been evaluated to be 5.7×10-20cm2and 1.7×10-19cm2, respectively. Experimental results are discussed, considering the model of the localized multihole excitation and its quenching.
SiO2/Poly-Si Multilayered Electron Beam Resist Process for Fabrication of Ultrasmall Tunnel Junctions
Authors: Wada Toshimi , Hirayama Motoki , Haraichi Satoshi , Ishii Ken'ichi , Hiroshima Hiroshi , Masanori Komuro Masanori Komuro
Published: January 2014

We have developed an SiO2/poly-Si multilayered electron beam resist process in order to overcome the resolution limit in conventional polymer electron beam resists and to form suspended masks for ultrasmall metal-insulator-metal tunnel junction fabrication. Using a solution of buffered HF and a mixed solution of HNO3 and HF as etching solutions for SiO2 and poly-Si, respectively, suspended masks for metal depositions were produced. Utilizing a multiple-angle deposition-oxidation-deposition method, we have realized an ultrasmall Al/Al2O3/Al tunnel junction array which exhibits a clear Coulomb staircase in the current-voltage characteristics at 12 K.
Time-Resolved Study of Carrier Transfer among InAs/GaAs Multi-Coupled Quantum Dots
Authors: Tackeuchi Atsushi , Nakata Yoshiaki , Muto Shunichi , Sugiyama Yoshihiro , Usuki Tatsuya , Nishikawa Yuji , Yokoyama Naoki , Osamu Wada Osamu Wada
Published: January 2014

Carrier transfer among InAs/GaAs self-organized multi-coupled quantum dots was studied using time-resolved photoluminescence. In the multi-coupled quantum dots, since quantum dots couple with the other dots laterally, the photoexcited carriers tunnel into the relatively larger quantum dots which have lower energy levels. The photoluminescence decay time of multi-coupled quantum dots strongly depends on the energy in contrast with conventional quantum dots. The energy dependence can be explained with a cascade-like tunneling model assuming a tunneling time between quantum dots of 1300 ps.
E1 and E1+Δ1 Photoellipsometry Spectra of n-GaAs Modeled by the Franz-Keldysh Theory
Authors: Xiong Yi-Ming , Kenichiro Kobayashi Kenichiro Kobayashi , Tadashi Saitoh Tadashi Saitoh
Published: January 2014

Photoellipsometry was applied to two n-GaAs substrates with the Si doping densities N
D of 3.0×1017 and 1.24×1018 cm-3. The measured spectra in the E
1 and E
1+Δ1 critical point (CP) regions were modeled using the Franz-Keldysh theory, which included broadening effects. Our objective was to determine built-in field strength, broadening, and CP energies for each sample. It was shown that, for the moderately doped sample (with N
D of 3.0×1017 cm-3) in which the built-in field variation over the depletion width was rather gradual as compared with that in a heavily doped GaAs sample, a uniform field model was sufficient for characterizing the measured spectra, whereas better agreement between the measured and calculated spectra was obtained for the heavily doped sample (with N
D of 1.24×1018 cm-3), if the field variation over the probe beam penetration depth was included in the model calculations.
Electrochromic Properties of Nickel Oxide Films Prepared by the Oxidation of Nickel-Carbon Composite Films
Authors: Sato Yoshiyuki , Shigeharu Tamura Shigeharu Tamura , Kensuke Murai Kensuke Murai
Published: January 2014

Electrochromic (EC) nickel oxide (NiO) films were prepared either by plasma oxidation of vacuum-deposited nickel-carbon (Ni–C) composite films or by thermal oxidation of those films. EC properties of the NiO films were measured by cyclic voltammetry in 1 M KOH. The degree of electrochromism in the NiO films depended not only on the Ni-to-C (Ni/C) ratio in the Ni–C films but also on the oxidation conditions of the Ni–C films. The NiO film with a Ni/C ratio of ∼0.6 showed the longest cycling ability among the films with three different Ni/C ratios (∼0.3, ∼0.6 and ∼1.2). The NiO film thermally oxidized at 500° C showed smaller transmission modulation and passed charge density than the plasma oxidized film, but could be electrochemically switched for more than 5000 cycles without serious residual coloration.
BETWEEN THE BABY AND THE BREAST
Authors: Strong S.I.
Published: July 2002

INRe C (A Child ) (HIV Test) [1999] 2 F.L.R. 1004, a local authority applied for a specific issue order to test a four-month-old baby girl for HIV. The mother of the child first tested positive for HIV in 1990, but adopted a highly sceptical stance towards generally accepted theories about HIV and AIDS, and refused conventional therapy for herself, preferring to rely on a healthy lifestyle as a prophylactic. The case arose when the baby's physician became aware not only that the mother was breast-feeding the child (despite the risk of transmission of HIV), but that the parents refused even to have their daughter tested for the virus in the belief that a healthy lifestyle was the optimal treatment even if she were HIV-positive.
HOBBES, PAYNE, AND A SHORT TRACT ON FIRST PRINCIPLES
Authors: RAYLOR TIMOTHY
Published: July 2002

An argument has erupted in recent years over the authorship of A short tract on first principles, a manuscript treatise traditionally regarded as the first philosophical work of Hobbes. Some have denied that it was Hobbes 's work, while others have insisted that it is. Among rival candidates, the prime suspect is Robert Payne, chaplain to the Cavendish family of Welbeck Abbey. This article offers a fresh assessment of the evidence for authorship by examining the manuscript and its contents in the light of the Cavendish family manuscripts, and of the various roles played at Welbeck by Payne. It argues that the tract was written by Payne for his patrons as an attempt to apply the method of contemporary mechanics to problems of human psychology, and that it was based in part – though only in part – upon ideas about the nature of light and motion expounded by Hobbes at Welbeck during the early 1630s.
ARCHAEOLOGICAL VIEWS ON A HISTORY OF LANDSCAPE CHANGE IN EAST AFRICA
Authors: SCHMIDT PETER R.
Published: July 2002

Since 1969 archaeological, paleobotanical and ethnographic research
in

Kagera region, north-western Tanzania (Map 1), have contributed to a deep-time

understanding of the ecological history of that region. The primary

insight that develops out of this interdisciplinary research is that changes
in

the ecology of the region can be linked directly to the productive economy

and the cultural values of its inhabitants. The development of iron technology

and settled agricultural life are the primary components in understanding
the

environmental changes that arose in this region over the last two millennia

or more. This paper provides an overview of the most salient observations

derived from this research program. I will begin with a short review of
the

history of Iron Age settlement, technology and major alterations made to
the

environment that form the backdrop to the specific reconstructions of forest

exploitation gleaned from charcoal excavated from iron-smelting furnaces

and from reconstructions of vegetational changes based on palynology.
DAILY TIME BUDGETS OF LONG-DISTANCE COMMUTING WORKERS IN TOKYO MEGALOPOLIS
Authors: UMEZAKI MASAHIRO , ISHIMARU HITOSHI , OHTSUKA RYUTARO
Published: July 2002

In Tokyo Megalopolis, long-distance commuting between residences in the suburbs and work places in the centre of the city was examined. Using a questionnaire, heads of household in two suburbs were asked about the influences of long commuting hours on their daily time budgets. The results showed that on workdays, the workers who spent longer commuting rose and left home for work earlier, and came back home and retired later; accordingly, both time spent on in-home activities on workdays and hours slept on the day before a workday were shorter. Comparison of time budgets between the subjects who work 5 and 6 days per week revealed more vulnerable influences of long commuting hours in the former than the latter. The expected health consequences of these findings are discussed from a biosocial/human ecological viewpoint.
Monitoring the microbiology of high quality milk by monthly
sampling over 2 years
Authors: DESMASURES NATHALIE , GUEGUEN MICHELINE
Published: July 2002

The concentrations of seven types of microorganism in the milk
produced
by farms using high quality milking procedures were monitored monthly.
The most
commonly encountered bacterium was Pseudomonas, whose concentration
varied
greatly between samples, but lactococci, lactobacilli and yeasts were also
present at
more stable concentrations. Staphylococcus aureus and
β-glucuronidase-positive
Escherichia coli were occasionally detected. Listeria
monocytogenes was found in the
samples from only one farm, while Yersinia enterocolitica
was never detected. There
were seasonal variations in the concentrations of lactobacilli and yeasts
over the 2
years monitored. The changes in certain bacteria (Lactococcus,

Lactobacillus) on any
given farm were very similar from one year to the next. The microbiological

characteristics of the milk from the farms examined seemed to be fairly
constant.
The profiles of some bacteria used for cheesemaking were relatively
stable over time.
It thus seems that the milk provided by different producers could be typed.
Passive scalar dispersion in a turbulent boundary layer from a line source at the wall and downstream of an obstacle
Authors: VINÇONT J.-Y. , SIMOËNS S. , AYRAULT M. , WALLACE J. M.
Published: July 2002

Simultaneous measurements of the velocity and scalar concentration fields have been
made in the plume emitting from a two-dimensional line source at the wall. The source
is one obstacle height, h, downstream of a two-dimensional square obstacle located on
the wall of a turbulent boundary layer. These measurements were made in two fluid
media: water and air. In both media particle image velocimetry (PIV) was used for the
velocity field measurements. For the scalar concentration measurements laser-induced
uorescence (LIF) was used for the water flow and Mie scattering diffusion (MSD) for
the air flow. Profiles of the mean and root-mean-square streamwise and wall-normal
velocity components, Reynolds shear stress and mean and root-mean-square scalar
concentration were determined at x = 4h and 6h downstream of the obstacle in the
recirculation region and above it in the mixing region. At these streamwise stations
the scalar fluxes, uc and vc, were also
determined from the simultaneous velocity and
scalar concentration field data. Both of these fluxes change sign from negative to
positive with increasing distance from the wall in the recirculating region at 4h.

A conditional analysis of the data was carried out by sorting them into the eight
categories (octants) given by the sign combinations of the three variables:
±u, ±v and ±c. The octants with
combinations of these three variables that correspond to types
of scalar concentration flux motions that can be approximated by mean gradient
scalar transport models are the octants that make the dominant contributions to uc
and vc. However, in the recirculating zone, counter-gradient transport type motions
also make significant contributions. Based on this conditional analysis, second-order
mean gradient models of the scalar and the momentum uxes were constructed; they
compare well to the measured values at 4h and 6h, particularly for the streamwise
scalar flux, uc.

Additional measurements of the velocity and concentration fields were made further
downstream of the reattachment location in the wake region of the air flow. The mean
velocity deficit profile determined from these measurements at x = 20h compares quite
well to a similarity solution profile obtained by Counihan, Hunt & Jackson (1974).
Their analysis was extended in the present investigation to the concentration field.
The similarity solution obtained for the mean concentration compares well to profiles
measured at x = 12h, 15h, and 20h, up to about three obstacle heights above the wall.
The dynamics and scaling law for particles suspended in shear flow with inertia
Authors: DING E-JIANG , AIDUN CYRUS K.
Published: July 2002

The effect of inertia on the dynamics of a solid particle (a circular cylinder, an elliptical
cylinder, and an ellipsoid) suspended in shear flow is studied by solving the discrete
Boltzmann equation. At small Reynolds number, when inertia is negligible, the behaviour
of the particle is in good agreement with the creeping flow solution showing
periodic orbits. For an elliptical cylinder or an ellipsoid, the results show that by
increasing the Reynolds number, the period of rotation increases, and eventually becomes
infinitely large at a critical Reynolds number, Rec. At Reynolds numbers above
Rec, the particle becomes stationary in a steady-state flow. It is found that the transition
from a time-periodic to a steady state is through a saddle-node bifurcation, and,
consequently, the period of oscillation near this transition is proportional to
[mid ]p−pc[mid ]−1/2,
where p is any parameter in the flow, such as the Reynolds number or the density ratio,
which leads to this transition at p = pc. This universal scaling law is presented along
with the physics of the transition and the effect of the inertia and the solid-to-fluid density
ratio on the dynamics. It is conjectured that this transition and the scaling law are
independent of the particle shape (excluding body of revolution) or the shear profile.
Optimal linear growth in swept boundary layers
Authors: CORBETT PETER , BOTTARO ALESSANDRO
Published: July 2002

Optimal perturbations for the family of three-dimensional boundary layers described
by the Falkner–Skan–Cooke similarity solution are obtained using a variational technique
in the temporal framework. The disturbances experiencing the most growth
take the form of vortices almost aligned with the external streamline at inception
and evolve into streaks. In subcritical flows these can attain about twice the transient
amplification observed in comparably forced two-dimensional flows. Possible connections
between optimal perturbations and exponentially amplified crossflow vortices
are explored.
A laboratory study of the velocity structure in an intrusive gravity current
Authors: LOWE RYAN J. , LINDEN P. F. , ROTTMAN JAMES W.
Published: July 2002

Laboratory experiments were performed in which an intrusive gravity current was
observed using shadowgraph and particle tracking methods. The intrusion was generated
in a two-layer fluid with a sharp interface by mixing the fluid behind a vertical
lock gate and then suddenly withdrawing the gate from the tank. The purpose of the
experiments was to determine the structure of the velocity field inside the intrusion
and the stability characteristics of the interface. Soon after the removal of the lock
gate, the front of the intrusive gravity current travelled at a constant speed close to
the value predicted by theory for an energy-conserving gravity current. The observed
structure of the flow inside the intrusion can be divided into three regions. At the
front of the intrusion there is an energy-conserving head region in which the fluid
velocity is nearly uniform with speed equal to the front speed. This is followed by a
dissipative wake region in which large billows are present with their associated mixing
and in which the fluid velocity is observed to be non-uniform and have a maximum
speed approximately 50% greater than the front speed. Behind the wake region is a
tail region in which there is very little mixing and the velocity field is nearly uniform
with a speed slightly faster than the front speed.
Moving contact lines in liquid/liquid/solid systems
Authors: SHIKHMURZAEV YULII D.
Published: July 2002

A general mathematical model which describes the motion of an

interface between immiscible viscous fluids along a smooth homogeneous
solid

surface is examined in the case of small capillary and Reynolds numbers.
The

model stems from a conclusion that the Young equation,

σ1 cos θ = σ2 − σ3,

which expresses the balance of tangential projection of the forces acting
on the

three-phase contact line in terms of the surface tensions

σi and the contact angle θ, together with
the

well-established experimental

fact that the dynamic contact angle deviates from the static one, imply
that

the surface tensions of contacting interfaces in the immediate vicinity
of the

contact line deviate

from their equilibrium values when the contact line is moving. The same
conclusion

also follows from the experimentally observed kinematics of the flow, which

indicates that liquid particles belonging to interfaces traverse the three-phase

interaction zone

(i.e. the ‘contact line’) in a finite time and become elements
of

another interface – hence their surface properties have to relax
to new

equilibrium values giving rise to

the surface tension gradients in the neighbourhood of the moving contact
line. The

kinematic picture of the flow also suggests that the contact-line motion
is only a

particular case of a more general phenomenon – the process of interface

formation or disappearance – and the corresponding mathematical model
should

be derived from first principles for this general process and then applied
to

wetting as well as to other relevant flows. In the present paper, the simplest

theory which uses this approach is formulated and applied to the moving

contact-line problem. The model describes the true kinematics of the flow
so that

it allows for the ‘splitting’ of the

free surface at the contact line, the appearance of the surface tension
gradients

near the contact line and their influence upon the contact angle and the

flow field. An analytical expression for the dependence of the dynamic
contact

angle on the contact-line speed and parameters characterizing properties
of

contacting media is derived and examined. The role of a ‘thin’

microscopic residual film formed by adsorbed

molecules of the receding fluid is considered. The flow field in the vicinity

of the contact line is analysed. The results are compared with experimental

data obtained for different fluid/liquid/solid systems.
Axisymmetric free boundary problems
Authors: SUSSMAN MARK , SMEREKA PETER
Published: July 2002

We present a number of three-dimensional axisymmetric free boundary problems
for two immiscible fluids, such as air and water. A level set method is used where
the interface is the zero level set of a continuous function
while the two fluids are
solutions of the incompressible Navier–Stokes equation.
We examine the rise and
distortion of an initially spherical bubble into cap bubbles and toroidal bubbles.
Steady solutions for gas bubbles rising in a liquid are computed, with favourable
comparisons to experimental data. We also study the inviscid limit and compare our
results with a boundary integral method. The problems of an air bubble bursting at
a free surface and a liquid drop hitting a free surface are also computed.
A pseudo-sound constitutive relationship
for the dilatational covariances in compressible turbulence
Authors: RISTORCELLI J. R.
Published: July 2002

The mathematical consequences of a few simple scaling assumptions
regarding the
effects of compressibility are explored using a singular perturbation idea and the
methods of statistical fluid mechanics. Representations
for the pressure–dilatation
and dilatational dissipation appearing in single-point moment closures for
compressible turbulence are obtained. The results obtained, in
as much as they come from
the same underlying procedure, represent a unified development for both dilatational
covariances. While the results are expressed in the context
of a statistical turbulence
closure they provide, with very few phenomenological assumptions, an interesting
and clear mathematical model for the ‘scalar’ effects of
compressibility. For homogeneous turbulence with quasi-normal
large scales the expressions derived are – in
the small turbulent Mach number squared isotropic
limit – exact. The expressions
obtained contain constants that have a precise physical significance and are defined
in terms of integrals of the longitudinal velocity correlation. The
pressure–dilatation
covariance is found to be a non-equilibrium phenomenon related to the time rate
of change of the kinetic energy and internal energy of the
turbulence; it is seen to scale with
α2M2t
εs
[Pk/ε−1]
(Sk/εs)2. Implicit in the
scaling is a dependence on the square of a gradient Mach number,
S[lscr ]/c. A new feature indicated by the analysis is
the appearance of the Kolmogorov scaling coefficient, α,
suggesting that large-scale quantities embodied in the well-established
ε∼u˜3/[lscr ]
relationship provide a link to
the structural dependence of the effects of compressibility. The expressions for the
dilatational dissipation are found to depend on the turbulent Reynolds number and
scale as M4t
(Sk/εs)4R−1t. The scalings for the
pressure–dilatation are found to produce
an excellent collapse of the pressure–dilatation data from
direct numerical simulation.
Instability properties of interacting jets
Authors: GREEN M. R. , CRIGHTON D. G.
Published: July 2002

Two parallel circular jets, in inviscid incompressible flow, with

uniform axial velocity

of the same magnitude and direction are placed near to one another, resulting
in a

strongly coupled field. A given (small) wavenumber in the axial direction
is taken

and a dispersion relation is found relating the frequency and wavenumber
for a given

disturbance mode, along with the velocity potentials within and exterior
to the jets.

The problem is tackled analytically using bipolar coordinates and asymptotic
forms

for the dispersion relation are found in the small-separation and large-separation

limits. Results are then compared with the corresponding two-dimensional
problem

for plane jets. It is concluded that close-proximity interactions greatly

destabilize the

varicose mode of the coupled jet, and greatly stabilize the sinuous mode.
Shock cavity implosion morphologies and
vortical projectile generation in axisymmetric
shock–spherical fast/slow bubble interactions
Authors: ZABUSKY N. J. , ZENG S. M.
Published: July 2002

Collapsing shock-bounded cavities in fast/slow (F/S) spherical

and near-spherical
configurations give rise to expelled jets and vortex rings. In this paper,
we
simulate with the Euler equations planar shocks interacting with an R12
axisymmetric
spherical bubble. We visualize and quantify results that show evolving
upstream and
downstream complex wave patterns and emphasize the appearance of vortex
rings.
We examine how the magnitude of these structures scales with Mach number.
The
collapsing shock cavity within the bubble causes secondary shock refractions
on the
interface and an expelled weak jet at low Mach number. At higher Mach numbers

(e.g. M=2.5) ‘vortical projectiles’ (VP) appear on

the downstream side of the bubble.
The primary VP arises from the delayed conical vortex layer generated at
the Mach
disk which forms as a result of the interaction of the curved incoming
shock waves
that collide on the downstream side of the bubble. These rings grow in
a self-similar
manner and their circulation is a function of the incoming shock Mach number.
At
M=5.0, it is of the same order of magnitude as the primary negative
circulation
deposited on the bubble interface. Also at M=2.5 and 5.0 a double
vortex layer
arises near the apex of the bubble and moves off the interface. It evolves
into a VP,
an asymmetric diffuse double ring, and moves radially beyond the apex of
the
bubble. Our simulations of the Euler equations were done with a second-order-accurate

Harten–Yee-type upwind TVD scheme with an approximate Riemann Solver
on mesh
resolution of 803×123 with a bubble of radius 55 zones.
Flow-induced morphological instability of a mushy layer
Authors: FELTHAM DANIEL L. , GRAE WORSTER M.
Published: July 2002

A morphological instability of a mushy layer due to a forced flow in the melt is
analysed. The instability is caused by flow induced in the mushy layer by Bernoulli
suction at the crests of a sinusoidally perturbed mush–melt interface. The flow in
the mushy layer advects heat away from crests which promotes solidification. Two
linear stability analyses are presented: the fundamental mechanism for instability is
elucidated by considering the case of uniform flow of an inviscid melt; a more complete
analysis is then presented for the case of a parallel shear flow of a viscous melt. The
novel instability mechanism we analyse here is contrasted with that investigated by
Gilpin et al. (1980) and is found to be more potent for the case of newly forming sea
ice.
Numerical solutions for unsteady gravity-driven
flows in collapsible tubes: evolution and
roll-wave instability of a steady state
Authors: BROOK B. S. , FALLE S. A. E. G. , PEDLEY T. J.
Published: July 2002

Unsteady flow in collapsible tubes has been widely studied for a number of different
physiological applications; the principal motivation for the work of this paper is
the study of blood flow in the jugular vein of an upright, long-necked subject (a
giraffe). The one-dimensional equations governing gravity- or pressure-driven flow in
collapsible tubes have been solved in the past using finite-difference (MacCormack)
methods. Such schemes, however, produce numerical artifacts near discontinuities such
as elastic jumps. This paper describes a numerical scheme developed to solve the one-dimensional equations using a more accurate upwind finite volume (Godunov) scheme
that has been used successfully in gas dynamics and shallow water wave problems.
The adapatation of the Godunov method to the present application is non-trivial due
to the highly nonlinear nature of the pressure–area relation for collapsible tubes.

The code is tested by comparing both unsteady and converged solutions with
analytical solutions where available. Further tests include comparison with solutions
obtained from MacCormack methods which illustrate the accuracy of the present
method.

Finally the possibility of roll waves occurring in collapsible tubes is also considered,
both as a test case for the scheme and as an interesting phenomenon in its own right,
arising out of the similarity of the collapsible tube equations to those governing
shallow water flow.
The production of subharmonic waves in the nonlinear evolution of wavepackets
in boundary layers
Authors: MEDEIROS MARCELLO A. F. , GASTER MICHAEL
Published: July 2002

The nonlinear evolution of wavepackets in a laminar boundary layer has been
studied experimentally. The packets were generated by acoustic excitations injected
into the boundary layer through a small hole in the plate. Various packets with
different phases relative to the envelope were studied. It was found that for all the
packets the nonlinearity involved the appearance of oblique modes of frequency
close to the subharmonic of the dominant two-dimensional wave. Moreover, the
results confirmed that the phase had a strong influence on the strength of the
nonlinear interaction. The experimental observations also indicated that although a
subharmonic resonance appeared to be present in the process, it alone could not
explain the nonlinear behaviour. The experiment demonstrated that the process must
also involve a mechanism that generates oblique waves of frequency lower than the
Tollmien–Schlichting band.
The effects of unstable stratification and
mean shear on the chemical reaction in grid turbulence
Authors: NAGATA KOUJI , KOMORI SATORU
Published: July 2002

The effects of unstable thermal stratification and mean shear on chemical reaction and
turbulent mixing were experimentally investigated in reacting and non-reacting liquid
mixing-layer flows downstream of a turbulence-generating grid. Experiments were
carried out under three conditions: unsheared neutrally stratified, unsheared unstably
stratified and sheared neutrally stratified. Instantaneous velocity and concentration
were simultaneously measured using the combination of a laser-Doppler velocimeter
and a laser-induced fluorescence technique. The results show that the turbulent mixing
is enhanced at both large and small scales by buoyancy under unstably stratified
conditions and therefore the chemical reaction is strongly promoted. The mean shear
acts to enhance the turbulent mixing mainly at large scales. However, the chemical
reaction rate in the sheared flow is not as large as in the unstably stratified case with
the same turbulence level, since the mixing at small scales in the sheared neutrally
stratified flow is weaker than that in the unsheared unstably stratified flow. The
unstable stratification is regarded as a better tool to attain unsheared mixing since
the shearing stress acting on the fluid is much weaker in the unstably stratified flow
than in the sheared flow.
Comment on ‘Collective effects in
bremsstrahlung in plasmas’
Authors: IGLESIAS CARLOS A.
Published: July 2002

In a recent study Tsytovich et al. [J. Plasma
Phys. 56, 127 (1996)] claimed to
obtain new expressions for electron–ion bremsstrahlung in plasmas.
It is shown,
however, that they interpreted earlier work incorrectly and simply reproduced
well-known results.
Polydorid species (Polychaeta: Spionidae) in Japan, with descriptions of morphology, ecology and burrow structure. 1. Boring species
Authors: Sato-Okoshi Waka
Published: July 2002

A total of 13 boring species of spionid polychaetes were extracted from 28 different calcareous substrata (i.e. mollusc shells, coralline algae and barnacle tests) from Japan. The spionids were: seven Polydora spp.: Polydora brevipalpa, P. websteri, P. curiosa, P. uncinata, P. aura, P. glycymerica, Polydora sp; five Dipolydora spp.: Dipolydora concharum, D. bidentata, D. alborectalis, D. giardi, D. armata; and one Carazziella sp.: Carazziella reishi. All of them inhabited self-excavated burrows in living and/or migratory calcareous substrata and they were never found from soft sediments. Burrow structures were species-specific. The Polydora species basically excavated simple U-shaped burrows, while the Dipolydora species excavated more varied, distinct burrows. The boring activity seemed species-specific among polydorids. This study attempts to summarize and discuss the biological characteristics of these boring species inhabiting Japan. In addition, P. curiosa, P. glycymerica, Polydora sp., D. giardi and C. reishi are new to Japan.
Species body size distribution patterns of marine benthic macrofauna assemblages from contrasting sediment types
Authors: Parry David M. , Kendall Michael A. , Rowden Ashley A. , Widdicombe Stephen
Published: July 2002

Species body size spectra have been constructed for macrofauna assemblages from four sites with contrasting sediment granulometry and heterogeneity in and around Plymouth Sound. The number of species and species turnover (β diversity) were higher on coarse sediment. While the fauna were distinct between sites, the median geometric size-class was conservative (class 14; 0.153–0.305 mg dry blotted weight). Only one site had significantly lower heterogeneity within the species size spectrum, yet this was the most heterogeneous sediment. As such, we were unable to reject the null hypothesis that species body size distribution patterns are conservative despite differences in sediment granulometry and heterogeneity.
A preliminary investigation of the lipids of abyssal holothurians from the north-east Atlantic Ocean
Authors: Ginger Michael L. , Santos Vera L.C.S. , Wolff George A.
Published: July 2002

The dominant lipids of seven species of abyssal holothurians (Oneirophanta mutabilis, Pseudostichopus villosus, Psychropotes longicauda, Deima validium, Parariza prouhoi, Amperima rosea and Molpadia blakei) have been examined in detail. Fatty acid compositions are qualitatively similar to those of shallow-water holothurians, but relatively higher amounts of unsaturated compounds in the deep sea animals are ascribed to an adaptation of the latter to maintain membrane fluidity at high pressure and low temperature. The sterol distributions of abyssal holothurians are complex, with mixtures of C26–C30 sterols being present in all of the animals. These are most likely to be dietary in origin; the holothurians substitute Δ5 with Δ7 unsaturation, via Δ5,7 or Δ0 intermediates. 14α-methylcholest-9(11)-enol, which is a common product of de novo biosynthesis in shallow-water holothurians is absent in all of the deep-water species. Furthermore, cholest-7-enol, the dominant product of de novo biosynthesis in shallow water animals, is a relatively minor component in all of the species, except A. rosea. This holothurian is also the only one that appears to assimilate 4α-methylsterols directly and contains high amounts of steryl sulphates. There are significant interspecies differences in the free sterol distributions which may reflect their different feeding strategies or niches.
Comparisons of fatty acid and stable isotope ratios in symbiotic and non-symbiotic brittlestars from Oban Bay, Scotland
Authors: McKenzie J. Douglas , Black Kenneth D. , Kelly Maeve S. , Newton Lyn C. , Handley Linda L. , Scrimgeour Charles M. , Raven John A. , Henderson R. James
Published: July 2002

The bed-forming brittlestars Ophiothrix fragilis, Ophiocomina nigra and Amphiura chiajei from Oban Bay, Scotland were studied using methods previously employed to study chemoautotrophic symbioses. Ophiothrix fragilis and A. chiajei both contain symbiotic bacteria (SCB) while Ophiocomina nigra is non-symbiotic. Samples were taken of Ophiothrix fragilis at approximately two-week intervals for one year. Symbiotic bacteria numbers were determined by direct counting of homogenates of the arms of 50 individual brittlestars. Water samples were analysed for chlorophyll content. Stable isotope ratios for carbon and nitrogen were determined for each homogenate sample. Regular SCB counts were made on the infaunal brittlestar A. chiajei. Homogenate samples of Ophiothrix fragilis, A. chiajei and the non-symbiotic Ophiocomina nigra were analysed to produce fatty acid profiles for each species. Symbiotic bacteria count varied by up to one order of magnitude in both Ophiothrix fragilis and A. chiajei with no evidence of seasonality in this variation. Symbiotic bacteria number was inversely correlated with δ15N but no relationship was established with δ13C. 16:1ω7 and 18:1.ω7 fatty acids were used as putative bacterial markers. Both symbiotic species had higher percentages of 16:1ω7 than the non-symbiotic Ophiocomina nigra. However, only Ophiothrix fragilis appeared to receive appreciable quantities of 18:1ω7 from its SCB. The SCB are heterotrophic and may contribute to the nitrogen budget of the host. The two symbiotic species studied here derive the bulk of their nutrition from conventional feeding but SCB make significant, additional contributions.
Lethal Giardia from a wild-caught sulphur-crested
cockatoo (Cacatua galerita) established in vitro
chronically infects mice
Authors: UPCROFT J. A. , McDONNELL P. A. , GALLAGHER A. N. , CHEN N. , UPCROFT P.
Published: July 2002

An axenic culture of Giardia was established from a sample
of
infected intestine obtained following autopsy of a sulphur-crested cockatoo
(Cacatua galerita). The cockatoo recently captured in the wild
and with
good muscle tone died along with
several other cage mates, apparently of an overwhelming, acute infection
of
Giardia. Trophozoites which established in
the traditional, axenic Giardia medium (TYI-S-33 with supplementary
bile)
were morphologically identical to G.
duodenalis. When outbred Quackenbush Swiss neonatal mice were infected
with
trophozoites a chronic infection was
established and parasites were still present at 38 days post-inoculation.
Weight
gain by infected mice was reduced by 20%,
thus mimicking failure-to-thrive syndrome in children, and maximum parasite
load
was more than 3-fold higher in
comparison with other G. duodenalis strains. Analysis of the
electrophoretic karyotype, rDNA and hybridization studies
together with Giemsa- and trichrome-stained samples, and scanning electron
microscopy indicated that the bird-derived
Giardia belonged to the duodenalis group. This is the first report
of
infection of mammals with Giardia isolated from a
bird. These data may have potentially serious implications for contamination
of watersheds and establishment of zoonotic infections.
The butterfly Danaus chrysippus is infected by a male-killing Spiroplasma bacterium
Authors: JIGGINS F. M. , HURST G. D. D. , JIGGINS C. D. , v. d. SCHULENBURG J. H. G. , MAJERUS M. E. N.
Published: July 2002

Many insects carry maternally inherited bacteria which kill male offspring. Such bacteria will spread if male death benefits
the female siblings who transmit the bacterium, and they are therefore expected in insects with antagonistic sibling
interactions. We report that the butterfly Danaus chrysippus is host to a maternally inherited male-killing bacterium. Using
diagnostic PCR and rDNA sequence, the bacterium was identified as a Spiroplasma closely related to 2 ladybird beetle
male-killers and the tick symbiont Spiroplasma ixodetis. The male-killer was found to have a geographically restricted
distribution, with up to 40% of females being infected in East Africa, but no detectable infection in small samples from
other populations. Danaus chrysippus is a surprising host for a male-killer as its eggs are laid singly. This suggests that the
ecological conditions permitting male-killers to invade may be more widespread than previously realized.
Richness patterns in the parasite communities of exotic poeciliid fishes
Authors: DOVE A. D. M.
Published: July 2002

Three species of poeciliids (Gambusia holbrooki, Xiphophorus helleri and X. maculatus) and 15 species of ecologically similar
native freshwater fishes (mainly eleotrids, ambassids, melanotaeniids and retropinnids) were examined for parasite richness
to investigate parasite flux, qualitative differences, quantitative differences and the structuring factors in parasite communities
in the 2 fish types in Queensland, Australia. Theory suggests that poeciliids would harbour depauperate parasite
communities. Results supported this hypothesis; poeciliids harboured more species-poor parasite infracommunities and
regional faunas than natives (P < 0·0001), despite greater sampling effort for the former. Cluster analysis of
presence/absence data for poeciliids and the 6 most-sampled native fishes revealed that parasite communities of the 2 fish groups
are qualitatively distinct; the proportion of parasite species with complex life-cycles was lower in poeciliids than in native
species, and Myxosporea, Microspora, Coccidia and parasitic Crustacea were all absent from poeciliids. Limited exchange
of parasite species has occurred between natives and poeciliids. Logistic ordinal regression analysis revealed that fish
origin (exotic or native), environmental disturbance and host sex were all significant determinants of parasite community
richness (P < 0·05). Theoretical modelling suggests that poeciliids are at a competitive advantage over native fishes because
of their lack of parasites.
Identity: Logic, Ontology, Epistemology
Authors: WERTHEIMER ROGER
Published: July 2002

Greece is Hellas and Greeks are Hellenes. Azure is cobalt and everything (coloured) azure is (coloured) cobalt. Pre-Fregeans would call all these statements of identity. Frege taught us to distinguish between

Conaming [Name] [Name]. Ngh: Greece is Hellas g=h. Nac: Azure is cobalt a=c

Copredicating [Predicate] [Predicate]. PGH: Greeks are Hellenes (x)(Gx≡Hx).
PAC: Everything azure is cobalt (x)(Ax≡Cx)

Singular Predication [Name] [Predicate]. PcA: Como is azure Ac. PaC: Azure is a colour Ca. PaL: Azure is like indigo Lai. PgD: Greece defeated Persia Dgp.

With Frege the contrasts became marked but misconceived.
How We Can Be Moved by Anna Karenina, Green Slime, and a Red Pony
Authors: Hartz Glenn A.
Published: July 2002

From Colin Radford we have inherited the ‘fiction paradox’: How can we be moved by creatures of fiction? Answers recently offered by aestheticians presuppose a false theory of emotion and are inconsistent with emotional phenomenology as well as facts about human evolution, physiology, and anatomy. I argue that Kendall Walton's ‘Charles’ can genuinely fear the slime and yet avow that he does not consider it dangerous—all without being irrational. The solutions offered by Morreall, Moran, Hyslop, Boruah, Lamarque, and Neill are rejected as inadequate. Knowledge of how we can be moved probably lies outside philosophy altogether—in cognitive neuroscience.
The Trouble with Kant
Authors: Bird Graham
Published: July 2002

Anthony Quinton's ‘The Trouble with Kant’ (Philosophy, Vol. 72, no. 279, January, 1997, pp. 5–18) claims to expose radical faults in Kant's epistemology which are not pointed out ‘in the many commentators (he) has studied’ (p. 17). The faults are, initially, that Kant is a ‘wild and intellectually irresponsible arguer’ (p. 5), and finally that Kant's account of a priori intuitions and concepts is erroneous (p. 16). Quinton suggests that his objections are new, but the truth is that they, and the supposedly Kantian views against which they are directed, have formed a frequent response in commentators from Hegel to Strawson. The ‘wild and irresponsible arguer’ charge is, after all, a commonplace among the ‘fighting Kant tooth and nail’ commentators, though it remains to be shown that Kant is markedly worse than other philosophers of the same period. And the central claim against which Quinton directs his assault, that we impose a spatio-temporal-categorial framework on the manifold of sensation (pp. 5 and 7), has provoked fierce and extensive hostility. Throughout his article Quinton assumes an interpretation of Kant's claim in which his task is to show how our minds construct a common, objective, reality from a spatio-temporal-categorial synthesis ‘by applying a piece of mental apparatus ... to ... a manifold of sensation’ (p. 5). The familiar objections to a ‘coloured spectacles’ interpretation of Kant's account of space and time, and Strawson's initial rejection of the ‘imaginary subject of transcendental psychology’ (Bounds of Sense (London; Methuen, 1966) p. 32) belong to the same tradition.
Disability and psychiatric disorders in an urban community:
measurement, prevalence and outcomes
Authors: BASSETT S. S. , CHASE G. A. , FOLSTEIN M. F. , REGIER D. A.
Published: July 2002

Background. The purpose of this analysis was to examine:

(1) the prevalence of psychiatric disorders
among disabled people, using seven different measures of disability;
(2) variation in disability between and within psychiatric diagnostic categories;
and
(3) relationship of diagnosis and disability to health service utilization.

Method. Data were drawn from Phase I and Phase II of the
Eastern Baltimore Mental Health Survey, part of the Epidemiologic Catchment
Area
Program (ECA) conducted in 1980–1 to survey
mental morbidity within the adult population. A total of 810 individuals

received both a household
interview and a standardized clinical psychiatric evaluation. Estimated
prevalence rates were
computed using appropriate survey sampling weights.

Results. Prevalence of disability ranged from 2·5 to

19·5%, varying with specific disability measure.
Among those classified as disabled by any of the measures examined, 56
to 92%
had a psychiatric disorder and serious chronic medical conditions were
present
in the majority of these cases (54 to 78%). Disability was expressed differently

among the various diagnostic groups. Diagnostic
category and disability were significant independent predictors of medical

service utilization and receipt of disability payments.

Conclusions. The majority of disabled adults living in the
community
have diagnosable psychiatric
disorders, with the majority of these individuals suffering from significant
chronic medical
conditions as well, thus making co-morbidity the norm.