bluuebunny/crossref_metadata_2025 huggingface dataset:
Hypoplastic left heart syndrome diagnosed in fetal life: associated findings, pregnancy outcome and results of palliative surgery
Authors: Galindo A. , Nieto O. , Villagrá S. , Grañeras A. , Herraiz I. , Mendoza A.
Published: April 2009

Objectives

To analyze the main prenatal characteristics of hypoplastic left heart syndrome (HLHS), its association with extracardiac anomalies including increased nuchal translucency (NT) and the outcome of affected patients.

Methods

We searched our database for classical forms of HLHS (aortic atresia, mitral and aortic atresia and critical aortic stenosis evolved to a severely hypoplastic left ventricle) prenatally diagnosed between 1998 and 2006. Data on 101 fetuses were retrieved and analyzed.

Results

The main reason for referral was suspected heart defect on a routine ultrasound scan (82%). The mean gestational age at diagnosis was 21 weeks. Most cases were detected at ≤ 22 weeks (72%), the upper limit for termination of pregnancy (TOP) in our country (Spain). An intact atrial septum was diagnosed in 11 of the 58 fetuses (19%) in which pulmonary vein blood flow was assessed, and this diagnosis was proved to be correct in the six liveborn babies. Most fetuses (68%) had an isolated HLHS. Fourteen fetuses (14%) were chromosomally abnormal and all had associated extracardiac defects. NT was above the 95th centile in 21 of the 74 cases (28%) in which this measurement was available. 79% (58/73) of the cases in which HLHS was detected at ≤ 22 weeks were terminated, and no differences in the rate of TOP were found through the study period. Among the 43 continuing pregnancies, seven fetuses died in utero and there were 36 live births; in 12 cases the parents opted for compassionate care and 24 chose to have the infant surgically treated. In the cohort of intention‐to‐treat cases, the overall survival rate was 36% (9/25). This rate improved from 18% (2/11) in the period 1998–2002 to 50% (7/14) in 2003–2006. There were no survivors in cases with intact atrial septum or when there were associated defects. At follow‐up, 2/9 survivors suffered from significant neurological morbidity.

Conclusions

Fetal echocardiography allows an accurate diagnosis of HLHS, which is made in most instances in the first half of pregnancy. Despite the advantage offered by the prenatal detection of HLHS, which provides the opportunity to plan perinatal management, our up‐to‐date results show that the outlook for these fetuses is still poor, and highlight the importance of presenting these figures when counseling parents with affected fetuses. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
X‐ray scattering information of ED‐XRF technique for powdered fruit juice mixes
Authors: Sussulini A. , Lima A. G. , Figueiredo E. C. , Fernandes H. L. , Pinheiro S. C. L. , Bueno M. I. M. S. , Pereira F. M. V.
Published: April 2009

The initial main objective of this study was to evaluate the potentiality of energy‐dispersive x‐ray fluorescence (ED‐XRF) and principal component analysis (PCA) for qualitative analysis of artificial powdered fruit juice mixes. The X‐ray spectroscopy (XRS) technique can be useful for preliminary studies of food and beverage samples, such as metal content in this type of sample. In addition, sample pretreatment is not required, offering very fast acquisition of results. XRF spectra were obtained using an ED‐XRF system equipped with an Rh target x‐ray tube. The spectral region related to x‐ray scattering from the light elements (C, H, and O, among others) of the samples matrix. Specifically, x‐ray scattering was verified in the region (from 18.00 to 24.00 keV) where Compton and Rayleigh effects occur by the x‐ray source of conventional equipment of ED‐XRF. This region combined with PCA showed distinction of the samples with and without artificial sweeteners in their composition. In addition, two different artificial sweeteners (aspartame and cyclamate) were detected by x‐ray scattering. These results have paved way for the versatile ED‐XRF application for analyses of inorganic and organic composition in food and beverage samples, without pretreatment. Copyright © 2009 John Wiley & Sons, Ltd.
Accurate determination of the Ca:P ratio in rough hydroxyapatite samples by SEM‐EDS, PIXE and RBS—a comparative study
Authors: Bailey M. J. , Coe S. , Grant D. M. , Grime G. W. , Jeynes C.
Published: April 2009

The Ca:P ratio in a certified standard of hydroxyapatite was determined by X‐ray spectrometry (XRS), with the X‐rays excited by both electrons and ions using energy dispersive spectroscopy on the scanning electron microscope (SEM‐EDS) and particle‐induced X‐ray emission (PIXE). The certified value of Ca:P was accurately verified by 3 MeV 4He+ Rutherford Backscattering Spectrometry (RBS). We show that the demonstrably rough surface of this sample does not cause perturbation of the Ca:P ratio within the uncertainties of each of the XRS measurements. Copyright © 2009 John Wiley & Sons, Ltd.
Chemical composition and mass closure for PM10 aerosols during the 2005 dry season at a rural site in Morogoro, Tanzania
Authors: Mkoma Stelyus L. , Maenhaut Willy , Chi Xuguang , Wang Wan , Raes Nico
Published: April 2009

An intensive aerosol field campaign was carried out from 11 July to 11 August 2005 (dry season) at a rural site in Morogoro, Tanzania. The objectives were to determine the chemical composition of the atmospheric particulate matter (PM) and to examine to which extent the gravimetric PM mass can be explained by the measured aerosol components. Two low‐volume filter samplers were deployed, a PM10 filter holder with two Whatman QM‐A quartz fibre filters in series and a Gent PM10 stacked filter unit (SFU) sampler with coarse and fine Nuclepore polycarbonate filters. The samplers operated in parallel and a total of 51 parallel collections were made. All samples were analysed for the PM mass by weighing. Depending on the sampler type and/or collection substrate, further analyses were performed for 25 elements by particle‐induced x‐ray emission spectrometry, for major water‐soluble inorganic ions by ion chromatography, and for organic carbon and elemental carbon by a thermal—optical transmission technique. The PM10 mass, as derived from the SFU samples, was, on an average, 46 ± 12 µg/m3. Aerosol chemical mass closure calculations were made for this PM10 mass; eight aerosol components were considered and they explained 93% of the average PM10 mass. Organic matter (OM) and crustal matter were the dominant aerosol components; they accounted for, on an average, 44% and 33%, respectively, of the PM10 aerosol. The large contribution from OM is thought to originate mainly from the burning of biomass, especially of charcoal and agricultural residues. Copyright © 2009 John Wiley & Sons, Ltd.
“A New Sodium Borate: Na[B6O8(OH)3]·6H2O·H3BO3”
Authors: Köse Dursun Ali , Zümreoglu‐Karan Birgül , Hökelek Tuncer , Sahin Ertan
Published: April 2009

The original article to which this Erratum refers was published in Zeitschrift für Anorganische und Allgemeine Chemie 635 (3) 2009, 563‐566: DOI 10.1002/zaac.200801288.

The first formula in the Abstract is incorrect and should be replaced by Na[B6O8(OH)3]·6H2O·H3BO3
Surgical Management of Peritoneal Dialysis Peritonitis: The Impact of Peritoneal Sclerosis
Authors: Yates Phillip J. , Kitchen Jessica P. A. , Kaushik Monica , Nicholson Michael L.
Published: April 2009

Background

Peritonitis is a life‐threatening complication of peritoneal dialysis. Peritoneal sclerosis is associated with long‐term peritoneal dialysis. The aim of this study was to assess the effect of peritoneal sclerosis on outcomes following laparotomy for peritoneal dialysis peritonitis.

Methods

A series of 63 consecutive patients underwent laparotomy for peritoneal dialysis peritonitis. Patients were divided into two groups, those with and those without simple peritoneal sclerosis identified at laparotomy. Medical, anaesthetic, and surgical notes were used for data collection. Patients with known encapsulating peritoneal sclerosis were excluded from the study.

Results

Patients with simple peritoneal sclerosis had a statistically significant longer duration of peritoneal dialysis. They also had a significantly higher risk of major complications postoperatively and a greater relative risk for mortality.

Conclusions

There is an increased prevalence of simple peritoneal sclerosis with long‐term peritoneal dialysis. Patients with simple peritoneal sclerosis have higher incidence of postlaparotomy complications. Patients on long‐term peritoneal dialysis should be treated aggressively for peritoneal dialysis peritonitis to reduce complication/mortality rates. Evidence of simple peritoneal sclerosis at laparotomy should preclude further peritoneal dialysis.
Cerambycid girdling and water stress modify mesquite architecture and reproduction
Authors: Martínez Armando J. , López‐Portillo J. , Eben A. , Golubov J.
Published: April 2009

This study evaluated the effect of an outbreak of the cerambycid beetle, Oncideres rhodosticta, on branch growth and inflorescence production of the mesquite Prosopis glandulosa var. torreyana, and on larvae mortality in girdled branches at two sites (dry and wet) in the southern Chihuahuan Desert of Mexico. We compared stem growth responses to girdling in branches of similar sized trees from both sites over 42 months. The number of larvae per girdled branch was similar between sites, indicating similar ovipositing effort regardless of water stress. However, the proportion of dead larvae was significantly lower in trees at the dry site. On average, girdling reduced 96% of the stem length at both sites. At the end of the first year, 25% of the original stubs survived at the dry site, compared to 90% at the wet site. Girdling also broke apical dominance and allowed for the development of lateral buds from the surviving stubs, which produced many fewer branches and inflorescences at the dry site compared to the wet site, where a compact crown was developed. Water stress and girdling have a combined effect on mesquite architecture and reproduction, since more stubs died at the dry site while new branches from surviving stubs developed at the wet site, recovering the original lost biomass but changing the appearance of the tree.
Microsatellites reveal genetic differentiation among populations in an insect species with high genetic variability in dispersal, the codling moth,Cydia pomonella(L.) (Lepidoptera: Tortricidae)
Authors: Chen M.H. , Dorn S.
Published: April 2009

Little is known about genetic differentiation and gene flow in populations of insect species that have a high genetic variability in dispersal but lack morphologically visible morphs that disperse. These characteristics apply to the codling moth,Cydia pomonellaL. (Lepidoptera: Tortricidae), a major pest of fruits and nuts. Larvae were collected from three orchards each of pome fruits, stone fruits and nut trees in a major fruit growing area of Switzerland (Valais) and from six further (mainly apple) orchards throughout this country. Nine microsatellite loci were used to investigate genetic differentiation and the amount of gene flow among the sampled populations. All the loci were shown to be polymorphic in all populations. The number of alleles ranged from five to 15 over nine loci for the 15 populations. Significant genetic differentiation was noted among the populations from apple, apricot and walnut in the Valais region. Furthermore, among the eight populations sampled from apple in different geographic regions throughout Switzerland, AMOVA and pairwiseFSTanalysis revealed significant population genetic differentiation even between populations collected from orchards ≪10 km apart. These results indicate that a distinct prevailing characteristic, in the present case the sedentary behaviour of the moth, can shape population architecture.
Mortality of Atta sexdens rubropilosa (Hymenoptera: Formicidae) workers in contact with colony waste from different plant sources
Authors: Lacerda F.G. , Della Lucia T.M.C. , Pereira O.L. , Peternelli L.A. , Tótola M.R.
Published: April 2009

The objective of this work was to study the effect of colony waste on the mortality of workers of Atta sexdens rubropilosa Forel colonies fed with different plant substrates. Eight nests were used; two colonies each were fed with Acalypha wilkesiana Müller.Arg, Ligustrum japonicum Thunb, Eucalyptus urophylla S.T. Blake or a mixture of the three substrates in equal proportions. Irrespective of diet, being kept with waste led to higher mortality. However, workers that were kept in contact with waste produced by colonies fed Acalypha had higher average survival rate and later death when compared with workers from the other treatments. Workers from the Eucalyptus-fed colonies had the lowest survival rate and 50% of them died within four days of exposure to Eucalyptus waste. Trichoderma viride Pers. ex Gray, a fungus garden antagonist, and the entomopathogen Aspergillus flavus Link. ex Gray were present in the colonies supplied with all plants. The largest fungus diversity was verified in the waste of colonies fed Acalypha and the mixture of Acalypha, Ligustrum and Eucalyptus. Therefore, antibiotic properties of Acalypha did not reduce contaminant diversity but apparently minimized effects of pathogenic microorganisms present in the waste such as Asp. flavus. This may explain the highest survival rate of workers in this treatment.
SLAVERY AND ITS TRANSFORMATION IN THE KINGDOM OF KONGO: 1491–1800
Authors: HEYWOOD LINDA M.
Published: April 2009

Studies of slavery in Africa during the period of the Atlantic slave trade have largely ignored questions of how political processes affected enslavement during the period and also the extent to which notions of who could be enslaved were modified. Documentation for the kingdom of Kongo during the 1500s to 1800 allows us to explore how the trade was sustained and the social and political dynamics behind it. In a state that consistently exported large numbers of slaves throughout the period of the trade, kings of Kongo at first observed quite a pronounced distinction between foreign-born captives subject to enslavement and sale in the Atlantic trade and freeborn Kongos who were largely proctected from enslavement and sale overseas. In time, however, the distinctions that separated foreign-born and Kongos fell apart as later political authorities and others disregarded such distinctions and all Kongos became subject to enslavement and sale overseas. This was a product of internal Kongo conflicts, which witnessed the collapse of institutions and the redefinition of polity, what it meant to be a citizen or freeborn, and who could be enslaved.
Effects of moderate Damköhler number on miscible viscous fingering involving viscosity decrease due to a chemical reaction
Authors: NAGATSU YUICHIRO , KONDO YUSUKE , KATO YOSHIHITO , TADA YUTAKA
Published: April 2009

We have succeeded in experimentally investigating the effects of a moderate Damköhler number, Da (defined as the ratio between a characteristic time of fluid motion and that of a chemical reaction), for various Péclet numbers, Pe, on miscible viscous fingering involving a decrease in the viscosity of the displaced liquid due to a chemical reaction in Hele-Shaw cells. We achieved this by using a chemical reaction between a polymer solution and metal ions. Main analysis has been done for the radial fingering. In the range of Pe employed here, the fingering patterns without the reaction (Da = 0) were independent of Pe. The fingering patterns with the reaction depended on the single parameter, Da, and the area occupied by the fingering pattern near the injection hole increased with Da in the range of Da employed here. The ratio of the area occupied by the fingering pattern within the circle radius of which is the length of longest finger to the area of the circle increased with Da in the range of Da employed here. This result is opposite to that of Nagatsu et al. (J. Fluid Mech., vol. 571, 2007, p. 475), in which the area was decreased by the reaction decreasing the viscosity involving significantly high Da. Experiments in the linear geometry show that the shape of a single finger also depended on the single parameter, Da, and the finger width increased near the base with Da. This result is also opposite to that in the previous case in which the width of a single finger was considered to be decreased by the reaction. These results, interestingly, show that the effects of the decrease in the displaced liquid's viscosity due to chemical reaction on the fingering pattern for moderate Da are opposite to those for significantly high Da. A mechanism for the opposite effects on the fingering pattern depending on Da is discussed.
Interacting oscillatory boundary layers and wall modes in modulated
rotating convection
Authors: RUBIO A. , LOPEZ J. M. , MARQUES F.
Published: April 2009

Thermal convection in a rotating cylinder near onset is investigated using direct
numerical simulations of the Navier–Stokes equations with the Boussinesq
approximation in a regime dominated by the Coriolis force. For thermal driving
too small to support convection throughout the entire cell, convection sets in
as alternating pairs of hot and cold plumes in the sidewall boundary layer, the
so-called wall modes of rotating convection. We subject the wall modes to small
amplitude harmonic modulations of the rotation rate over a wide range of
frequencies. The modulations produce harmonic Ekman boundary layers at the top
and bottom lids as well as a Stokes boundary layer at the sidewall. These
boundary layers drive a time-periodic large-scale circulation that interacts
with the wall-localized thermal plumes in a non-trivial manner. The resultant
phenomena include a substantial shift in the onset of wall-mode convection to
higher temperature differences for a broad band of frequencies, as well as a
significant alteration of the precession rate of the wall mode at very high
modulation frequencies due to the mean azimuthal streaming flow resulting from
the modulations.
Saltating particles in a turbulent boundary layer: experiment and theory
Authors: CREYSSELS M. , DUPONT P. , EL MOCTAR A. OULD , VALANCE A. , CANTAT I. , JENKINS J. T. , PASINI J. M. , RASMUSSEN K. R.
Published: April 2009

The work presented here focuses on the analysis of a turbulent boundary layer saturated with saltating particles. Experiments were carried out in a wind tunnel 15m long and 0.6m wide at the University of Aarhus in Denmark with sand grains 242 μm in size for wind speeds ranging from the threshold speed to twice its value. The saltating particles were analysed using particle image velocimetry (PIV) and particle-tracking velocimetry (PTV), and vertical profiles of particle concentration and velocity were extracted. The particle concentration was found to decrease exponentially with the height above the bed, and the characteristic decay height was independent of the wind speed. In contrast with the logarithmic profile of the wind speed, the grain velocity was found to vary linearly with the height. In addition, the measurements indicated that the grain velocity profile depended only slightly on the wind speed. These results are shown to be closely related to the features of the splash function that characterizes the impact of the saltating particles on a sandbed. A numerical simulation is developed that explicitly incorporates low-velocity moments of the splash function in a calculation of the boundary conditions that apply at the bed. The overall features of the experimental measurements are reproduced by simulation.
Flow patterns in the sedimentation of an elliptical particle
Authors: XIA ZHENHUA , CONNINGTON KEVIN W. , RAPAKA SAIKIRAN , YUE PENGTAO , FENG JAMES J. , CHEN SHIYI
Published: April 2009

We study the dynamics of a single two-dimensional elliptical particle sedimenting in a Newtonian fluid using numerical simulations. The main emphasis in this work is to study the effect of boundaries on the flow patterns observed during sedimentation. The simulations were performed using a multi-block lattice Boltzmann method as well as a finite-element technique and the results are shown to be consistent. We have conducted a detailed study on the effects of density ratio, aspect ratio and the channel blockage ratio on the flow patterns during sedimentation. As the channel blockage ratio is varied, our results show that there are five distinct modes of sedimentation: oscillating, tumbling along the wall, vertical sedimentation, horizontal sedimentation and an inclined mode where the particle sediments with a non-trivial orientation to the vertical. The inclined mode is shown to form a smooth bridge between the vertical and horizontal modes of sedimentation. For narrow channels, the mode of sedimentation is found to be sensitively dependent on the initial orientation of the particle. We present a phase diagram showing the transitions between the various modes of sedimentation with changing blockage ratio of the channel.
Water entry of spinning spheres
Authors: TRUSCOTT TADD T. , TECHET ALEXANDRA H.
Published: April 2009

The complex hydrodynamics of water entry by a spinning sphere are investigated experimentally for low Froude numbers. Standard billiard balls are shot down at the free surface with controlled spin around one horizontal axis. High-speed digital video sequences reveal unique hydrodynamic phenomena which vary with spin rate and impact velocity. As anticipated, the spinning motion induces a lift force on the sphere and thus causes significant curvature in the trajectory of the object along its descent, similar to a curveball pitch in baseball. However, the splash and cavity dynamics are highly altered for the spinning case compared to impact of a sphere without spin. As spin rate increases, the splash curtain and cavity form and collapse asymmetrically with a persistent wedge of fluid emerging across the centre of the cavity. The wedge is formed as the sphere drags fluid along the surface, due to the no-slip condition; the wedge crosses the cavity in the same time it takes the sphere to rotate one-half a revolution. The spin rate relaxation time plateaus to a constant for tangential velocities above half the translational velocity of the sphere. Non-dimensional time to pinch off scales with Froude number as does the depth of pinch-off; however, a clear mass ratio dependence is noted in the depth to pinch off data. A force model is used to evaluate the lift and drag forces on the sphere after impact; resulting forces follow similar trends to those found for spinning spheres in oncoming flow, but are altered as a result of the subsurface air cavity. Images of the cavity and splash evolution, as well as force data, are presented for a range of spin rates and impact speeds; the influence of sphere density and diameter are also considered.
A wave driver theory for vortical waves propagating across junctions with application to those between rigid and compliant walls
Authors: SEN P. K. , CARPENTER P. W. , HEGDE S. , DAVIES C.
Published: April 2009

A theory is described for propagation of vortical waves across alternate rigid and compliant panels. The structure in the fluid side at the junction of panels is a highly vortical narrow viscous structure which is idealized as a wave driver. The wave driver is modelled as a ‘half source cum half sink’. The incoming wave terminates into this structure and the outgoing wave emanates from it. The model is described by half Fourier–Laplace transforms respectively for the upstream and downstream sides of the junction. The cases below cutoff and above cutoff frequencies are studied. The theory completely reproduces the direct numerical simulation results of Davies & Carpenter (J. Fluid Mech., vol. 335, 1997, p. 361). Particularly, the jumps across the junction in the kinetic energy integral, the vorticity integral and other related quantities as obtained in the work of Davies & Carpenter are completely reproduced. Also, some important new concepts emerge, notable amongst which is the concept of the pseudo group velocity.
Transition to turbulence in the wake of a fixed sphere in mixed convection
Authors: KOTOUČ MIROSLAV , BOUCHET GILLES , DUŠEK JAN
Published: April 2009

The thermal effect on axisymmetry breaking and transition to turbulence in the wake of a fixed heated sphere is investigated in the mixed convection configurations commonly known as ‘assisting’ and ‘opposing’ flows in which the buoyancy tends, respectively, to accelerate and decelerate the flow. The study is carried out in the Ri–Re parameter plane (Ri being the mixed convection parameter – the Richardson number) for two values of Prandtl number – 0.72 (≈air and many gases) and 7 (≈water). We show that convection affects considerably the transition (as compared to that observed in the wake of an unheated sphere) even at moderate Richardson numbers. The latter are taken to be positive in assisting flow and negative in opposing one. In this notation, it can be said that convection shifts the primary-instability threshold to higher Reynolds numbers with increasing Richardson number. In assisting flow, the primary bifurcation is always regular, but at Ri ≥ 0.6 it appears in azimuthal subspaces associated with higher azimuthal wavenumbers m > 1. The transition scenario is characterized by a large variety of regimes explainable by nonlinear interactions between different azimuthal subspaces. On the side of higher (positive) Richardson numbers the axisymmetric flow is found stable up to Re = 1400 at Pr = 0.72 and Ri = 0.7. In opposing flow, the m = 1 subspace is always the most unstable, but the regular bifurcation gives way to a Hopf one at Ri < −0.1. Close to the junction of both bifurcations a similar variety of regimes precedes the transition to chaos as in assisting flow. On the side of negative Richardson numbers the primary (Hopf) bifurcation threshold is found as low as Re = 100 at Ri = −0.25 and at both investigated Prandtl numbers. After a primary periodic regime characterized by vortex shedding with a symmetry plane, the transition proceeds via a series of increasingly irregular helical regimes.
Particle capture in binary solidification
Authors: KAO JUSTIN C. T. , GOLOVIN ALEXANDER A. , DAVIS STEPHEN H.
Published: April 2009

We examine the interaction of a spherical foreign particle with a propagating solidification front in a binary alloy. Depending on the material properties and the speed of the front, the particle may be pushed ahead of the front, or engulfed and incorporated into the solid phase. We apply numerical boundary integral and continuation methods to determine the critical speed for particle capture, as a function of the system parameters. We reconcile the differing predictions of previous theoretical works, and show that many typical systems may obey a new scaling of the critical speed, as obtained here. We show that due to constitutional undercooling, the presence of solute decreases particle speeds by an order of magnitude below those for a single-component system. We briefly consider the case of spherical bubbles, where thermocapillary and solutocapillary effects play a large role.
Hydrodynamic propulsion of human sperm
Authors: GILLIES ERIC A. , CANNON RICHARD M. , GREEN RICHARD B. , PACEY ALLAN A.
Published: April 2009

The detailed fluid mechanics of sperm propulsion are fundamental to our understanding of reproduction. In this paper, we aim to model a human sperm swimming in a microscope slide chamber. We model the sperm itself by a distribution of regularized stokeslets over an ellipsoidal sperm head and along an infinitesimally thin flagellum. The slide chamber walls are modelled as parallel plates, also discretized by a distribution of regularized stokeslets. The sperm flagellar motion, used in our model, is obtained by digital microscopy of human sperm swimming in slide chambers. We compare the results of our simulation with previous numerical studies of flagellar propulsion, and compare our computations of sperm kinematics with those of the actual sperm measured by digital microscopy. We find that there is an excellent quantitative match of transverse and angular velocities between our simulations and experimental measurements of sperm. We also find a good qualitative match of longitudinal velocities and computed tracks with those measured in our experiment. Our computations of average sperm power consumption fall within the range obtained by other authors. We use the hydrodynamic model, and a prototype flagellar motion derived from experiment, as a predictive tool, and investigate how sperm kinematics are affected by changes to head morphology, as human sperm have large variability in head size and shape. Results are shown which indicate the increase in predicted straight-line velocity of the sperm as the head width is reduced and the increase in lateral movement as the head length is reduced. Predicted power consumption, however, shows a minimum close to the normal head aspect ratio.
Computational study of optical distortions by separated shear layers and turbulent wakes
Authors: MANI ALI , MOIN PARVIZ , WANG MENG
Published: April 2009

The flow over a circular cylinder atReD= 3900 and 10000 andM= 0.4 is considered a platform to study the aero-optical distortions by separated shear layers and turbulent wakes. The flow solution is obtained by large eddy simulation (LES) and validated against previous experimental and numerical results. The fluctuating refractive index obtained from LES is used in a ray-tracing calculation to determine wavefront distortions after the beam passes through the turbulent region. Free-space propagation to the far field is computed using Fourier optics. The optical statistics are analysed for different conditions in terms of optical wavelength, aperture size and the beam position. It is found that there exists an optimal wavelength which maximizes the far-field peak intensity. Optical results at both Reynolds numbers are compared. The optical distortion by the downstream turbulent wake is found to be Reynolds number insensitive. However, due to their different transition mechanisms, distortions by the near wake regions are different in the two flows. The aero-optical effects of different flow scales are examined using filtering and grid refinement. Through a grid convergence study it is confirmed that an adequately resolved LES can capture the aero-optics of highly aberrating flows without requiring additional subgrid scale model for the optics.
Modelling carbon dioxide sequestration in layered strata
Authors: NEUFELD JEROME A. , HUPPERT HERBERT E.
Published: April 2009

Motivated by the geological sequestration of carbon dioxide (CO2), we study the propagation of gravity currents in a porous medium bounded by a thin layer of much lower permeability. We formulate a model for drainage assuming that the fluid remains simply connected throughout. Using this model we examine the propagation of both two-dimensional and axisymmetric currents numerically. We find that for the fixed-flux situation solutions approach a steady state which is described analytically. The approach to this final solution depends on both the permeability contrast and thickness of the thin layer, and in many cases the current first overshoots before relaxing back to its ultimate steady state. Finally, we examine propagation along multiple thin, lower permeability layers as a reduced-order model of the plume of CO2 currently being injected at Sleipner in the North Sea.
Pseudo-three-timescale approximation of exponentially modulated free-surface waves
Authors: KELMANSON MARK A.
Published: April 2009

A novel pseudo-three-timescale asymptotic procedure is developed and implemented for obtaining accurate approximations to solutions of an evolution equation arising in thin-film free-surface viscous flow. The new procedure, which employs strained fast and slow timescales, requires considerably fewer calculations than its standard three-timescale counterpart employing fast, slow and slower timescales and may readily be applied to other evolution equations of fluid mechanics possessing wave-like solutions exhibiting exponential decay in amplitude and variations in phase over disparate timescales. The new method is validated on the evolution of free-surface waves on a thin, viscous film coating the exterior of a horizontal rotating cylinder and is shown to yield accurate solutions up to non-dimensional times exceeding by an order of magnitude those of previous related studies. Results of the new method applied to this test problem are demonstrated to be in excellent agreement, over large timescales, with those of corroborative spectrally accurate numerical integrations.
Frequency responses of streamwise-constant perturbations in channel flows of Oldroyd-B fluids
Authors: HODA NAZISH , JOVANOVIĆ MIHAILO R. , KUMAR SATISH
Published: April 2009

Non-modal amplification of disturbances in streamwise-constant channel flows of Oldroyd-B fluids is studied from an input–output point of view by analysing the responses of the velocity components to spatio-temporal body forces. These inputs into the governing equations are assumed to be harmonic in the spanwise direction and stochastic in the wall-normal direction and in time. An explicit Reynolds number (Re) scaling of frequency responses from different forcing to different velocity components is developed, showing the sameRedependence as in Newtonian fluids. It is found that some of the frequency response components peak at non-zero temporal frequencies. This is in contrast to Newtonian fluids, where peaks are always observed at zero frequency, suggesting that viscoelastic effects introduce additional time scales and promote development of flow patterns with smaller time constants than in Newtonian fluids. The temporal frequencies, corresponding to the peaks in the components of frequency response, decrease with an increase in viscosity ratio (ratio of solvent viscosity to total viscosity) and show maxima for non-zero elasticity number. Our analysis of the Reynolds–Orr equation demonstrates that the energy-exchange term involving the streamwise/wall-normal polymer stress component τxyand the wall-normal gradient of the streamwise velocity ∂yubecomes increasingly important relative to the Reynolds-stress term as the elasticity number increases and is thus the main driving force for amplification in flows with strong viscoelastic effects.
Tick-borne disease systems emerge from the shadows: the beauty lies in molecular detail, the message in epidemiology
Authors: RANDOLPH S. E.
Published: April 2009

This review focuses on some of the more ground-shifting advances of recent decades, particularly those at the molecular and cellular level that illuminate mechanisms underpinning the natural ecology of tick-host-pathogen interactions and the consequent epidemiology of zoonotic infections in humans. Knowledge of components of tick saliva, now recognized as the central pillar in the tick's ability to complete its blood meal and the pathogen's differential ability to use particular hosts for transmission, has burgeoned with new molecular techniques. Functional studies have linked a few of them to saliva-assisted transmission of non-systemic infections between co-feeding ticks, the quantitative key to persistent cycles of the most significant tick-borne pathogen in Europe. Human activities, however, may be equally important in determining dynamic patterns of infection incidence in humans.
The ecology of parasites of freshwater fishes: the search for patterns
Authors: KENNEDY C. R.
Published: April 2009

Developments in the study of the ecology of helminth parasites of freshwater fishes over the last half century are reviewed. Most research has of necessity been field based and has involved the search for patterns in population and community dynamics that are repeatable in space and time. Mathematical models predict that under certain conditions host and parasite populations can attain equilibrial levels through operation of regulatory factors. Such factors have been identified in several host-parasite systems and some parasite populations have been shown to persist over long time-periods. However, there is no convincing evidence that fish parasite populations are stable and regulated since in all cases alternative explanations are equally acceptable and it appears that they are non-equilibrial systems. It has proved particularly difficult to detect replicable patterns in parasite communities. Inter-specific competition, evidenced by functional and numerical responses, has been detected in several communities but its occurrence is erratic and its significance unclear. Some studies have failed to find any nested patterns in parasite community structure and richness, whereas others have identified such patterns although they are seldom constant over space and time. Departures from randomness appear to be the exception and then only temporary. It appears that parasite communities are non-equilibrial, stochastic assemblages rather than structured and organized.
Proliferative kidney disease (PKD) of rainbow trout: temperature- and time-related changes ofTetracapsuloides bryosalmonaeDNA in the kidney
Authors: BETTGE K. , SEGNER H. , BURKI R. , SCHMIDT-POSTHAUS H. , WAHLI T.
Published: April 2009

Proliferative kidney disease (PKD) of salmonids, caused byTetracapsuloides bryosalmonae, can lead to high mortalities at elevated water temperature. We evaluated the hypothesis that this mortality is caused by increasing parasite intensity.T. bryosalmonae-infected rainbow trout (Oncorhynchus mykiss) were reared at different water temperatures and changes in parasite concentrations in the kidney were compared to cumulative mortalities. Results of parasite quantification by a newly developed real-time PCR agreed with the number of parasites detected by immunohistochemistry, except for very low or very high parasite loads because of heterogenous distribution of the parasites in the kidney. Two experiments were performed, where fish were exposed to temperatures of 12, 14, 16, 18 or 19°C after an initial exposure to an infectious environment at 12–16°C resulting in 100% prevalence of infected fish after 5 to 14 days of exposure. While mortalities differed significantly between all investigated water temperatures, significant differences in final parasite loads were only found between fish kept at 12°C and all other groups. Differences in parasite load between fish kept at 14°C to 19°C were not significant. These findings provide evidence that there is no direct link between parasite intensity and fish mortality.
THE FAUST LEGEND AND ITS ROLE IN ALFRED SCHNITTKE'S WORK
Authors: Khanina Lilia
Published: April 2009

Alfred Schnittke (1934–1998) is among the most notable composers in the second half of the 20th century. Over the past 20 years his work has won wide acceptance and greater international attention. His music, performed by world-class musicians in countless countries and in the most prestigious concert halls, has become an integral part of Russian cultural heritage. Schnittke's vast popularity is evident in the existence of so many publications, reviews, and dissertations not only in Russia but all over the world. However, some aspects of the composer's life and music remain unexplored, and a study of Schnittke's work would not be complete without examining one particular subject which influenced Schnittke throughout his creative life: the Faust Legend. The Faustian Legend ‘was among the forces that supported Schnittke's dialogue with the past and shaped his identity’. Before delving into this topic it would be logical to give a brief excursus in the history of the Faustian legend itself.
NICCOLÒ CASTIGLIONI IN INTERVIEW, 1995 BY LUIGI PESTALOZZA
Authors: Causton Richard
Published: April 2009

It is only in the twelve years since his death that the importance of Niccolò Castiglioni's music has begun to be properly appreciated. A growing list of recordings and scholarly writings has contributed to a reassessment of his importance and Alessandro Solbiati's view of Castiglioni as ‘one of the greatest Italian composers of the 20th century’ now looks likely to find general acceptance.
Towards a Theory of Cruel Britannia: Coolness, Cruelty, and the 'Nineties
Authors: Urban Ken
Published: April 2009

The explosion of ‘in-yer-face’ theatre that dominated the British stage in the 'nineties has had both vocal champions and detractors. Here, Ken Urban examines the emergence of this kind of theatre within the cultural context of ‘cool Britannia’ and suggests that the plays of writers such as Mark Ravenhill and Sarah Kane explore the possibilities of cruelty and nihilism as a means of countering cynicism and challenging mainstream morality's interpretation of the world. Ken Urban is a playwright and director, whose plays The Female Terrorist Project and I [hearts] KANT are currently being produced by the Committee Theatre Company in New York City. His play about the first US Secretary of Defense, The Absence of Weather, will premiere in Los Angeles at Moving Arts Theatre Company, which has named it the winner of its national new play award. At the request of the Sarah Kane Estate, Urban directed the New York premiere of her play Cleansed. He teaches Modern Drama and Creative Writing in the English Department at Rutgers University, New Brunswick. An early version of this article was first presented at the ‘In-Yer-Face? British Drama in the 1990s’ conference at the University of the West of England, Bristol, in September 2002.
The Market Overt Method to Obtain Ownership of Lost or Stolen Goods: Comment on Manning v. Algard Estate, [2008] BCSC 1129
Authors: MacDougall Bruce
Published: April 2009

Stephanie Manning's mother, Marina Ovsenek, had a penchant for garage sales. In 2000 the daughter was driving the mother to the hospital for her cancer treatment when they stopped at one of these garage sales. The mother paid $5 to buy a box containing a brooch and five gold-colored coins. She kept these in the room in her house that was used to store various items, including other trinkets bought at garage sales.
A Tug of War Between Heritage Conservation and Property Rights: Some Success at Last for Heritage Conservation—City of Cape Town v. Oudekraal Estates (Pty) Ltd. [2007] JOL 20887 (C)
Authors: Beukes Margaret
Published: April 2009

When the idea of heritage conservation arises, one specific facet of the ensuing reflection is bound to emerge at some stage: the (inevitable) tension between property rights, on the one hand, and the right to culture (of which heritage conservation is an aspect), on the other. This tension intensifies when the cultural material to be conserved concerns a traditionally sensitive issue—that of the burial places of the ancestors of people designated in the South African context as previously disadvantaged.
Building Destruction: The Consequences of Rising Urbanization on Cultural Heritage in the Ramallah Province
Authors: al-Houdalieh Salah H. , Sauders Robert R.
Published: April 2009

Urbanization, particularly in terms of private housing construction, constitutes a mounting threat to cultural heritage sites in Palestine. At risk are not only archaeological sites, but traditional architecture and other locations of cultural heritage. The Ramallah province serves as a practical case study by which to examine how this process of urbanization affects the cultural heritage of the region, because of the increased rate of development the province has experienced over the past decade. This urbanization has proceeded with relatively little governmental oversight and administration by the Palestinian National Authority (PNA) and is typified by an absence of planning, which often places sites of cultural, historical, and archaeological significance in severe jeopardy. This article considers both the internal and external factors affecting the urbanization of Ramallah and proposes solutions to mitigate the dangers to cultural heritage posed by unchecked urban growth.
Presenting Past Landscapes: An Approach to Visual Landscape Integrity as a Tool for Archeological Heritage Management
Authors: Mosler Saruhan
Published: April 2009

Archaeological sites are composed of unique, complex landscape settings including architectural remains, visually and spatially interrelated spaces, and ecologies with topographical features and landforms framing them. Today, they are subject to many pressures caused by developmental changes as well as improper conservation and planning strategies. One reason is that heritage conservation is still heavily focused on architectural features and less on the landscape setting. Wider landscape components set an authentic backdrop for cultural heritage and make the setting vivid and legible. Concentrating on this trend, this article explores the visual values of archaeological sites from the tripartite conceptualization view of visual landscape integrity, namely considering the archaeological landscape setting as an artifact, three-dimensional space, and scenery. Using the archaeological site complex of Bergama in Western Turkey as a case study, I propose a visual landscape–oriented approach as a tool for the sustainable conservation and presentation of heritage sites in the process of cultural resource management.
A role for aquaporin-4 in fluid regulation in the inner retina
Authors: GOODYEAR MELINDA J. , CREWTHER SHEILA G. , JUNGHANS BARBARA M.
Published: April 2009

Many diverse retinal disorders are characterized by retinal edema; yet, little experimental attention has been given to understanding the fundamental mechanisms underlying and contributing to these fluid-based disorders. Water transport in and out of cells is achieved by specialized membrane channels, with most rapid water transport regulated by transmembrane water channels known as aquaporins (AQPs). The predominant AQP in the mammalian retina is AQP4, which is expressed on the Müller glial cells. Müller cells have previously been shown to modulate neuronal activity by modifying the concentrations of ions, neurotransmitters, and other neuroactive substances within the extracellular space between the inner and the outer limiting membrane. In doing so, Müller cells maintain extracellular homeostasis, especially with regard to the spatial buffering of extracellular potassium (K+) via inward rectifying K+ channels (Kir channels). Recent studies of water transport and the spatial buffering of K+ through glial cells have highlighted the involvement of both AQP4 and Kir channels in regulating the extracellular environment in the brain and retina. As both glial functions are associated with neuronal activation, controversy exists in the literature as to whether the relationship is functionally dependent. It is argued in this review that as AQP4 channels are likely to be the conduit for facilitating fluid homeostasis in the inner retina during light activation, AQP4 channels are also likely to play a consequent role in the regulation of ocular volume and growth. Recent research has already shown that the level of AQP4 expression is associated with environmentally driven manipulations of light activity on the retina and the development of myopia.