bluuebunny/crossref_metadata_2025 huggingface dataset:
Fracture‐related hip pain in elderly patients with proximal femoral fracture after discharge from stationary treatment
Authors: Dasch Burkhard , Endres Heinz G. , Maier Christoph , Lungenhausen Margitta , Smektala Rüdiger , Trampisch Hans J. , Pientka Ludger
Published: May 2007

Background: Proximal femoral fracture is a common condition in the elderly but very little is known about fracture‐related hip pain in these patients after discharge from stationary treatment.

Aims: To identify risk factors associated with persistent hip pain in elderly hip‐fracture patients.

Methods: We analysed data from a large observational study, evaluating the health care situation of hip‐fracture patients between January 2002 and September 2003 in Germany. For this analysis, we focused on a sub‐sample of patients who were 65 years or older, had sustained an isolated proximal femoral fracture and had undergone surgical intervention. A telephone interview was conducted 6–12 months after discharge. Pain intensity, pain‐related disability and severity of chronic pain were measured using the Graded Chronic Pain Scale (GCPS). Multivariate linear regression methods were applied to test hospital patient data for their value in predicting post‐hospitalisation presence of fracture‐related pain.

Results: In total, 1541 patients (mean age 78.4, 76.1% female) were enrolled in this analysis. The prevalence of fracture‐related hip pain was 13.4% (206/1541). Among these 206 patients, 57.3% had pain intensity scores ≥50, 65.0% had pain disability scores ≥50, and the severity of chronic pain (Grades 1–4) was assessed as follows: (1) 34.0%, (2) 19.4%, (3) 31.5%, (4) 15.1%. The clinical variables age, weight and operative procedure were found to be predictive of post‐hospitalisation fracture‐related pain.

Conclusions: This analysis shows that a substantial percentage of elderly patients with proximal femoral fracture suffer intense fracture‐related hip pain after stationary treatment.
Nuchal translucency as a predictor of adverse pregnancy outcome
Authors: Piazze J. , Anceschi M.M. , Cerekja A. , La Torre R. , Pala A. , Papa A. , Cosmi E.V.
Published: May 2007

Background Thickened nuchal translucency (NT) has been related to fetal genetic syndromes, structural abnormalities, and other diseases. The aim of this research was to evaluate the association of NT with adverse pregnancy outcomes. Study design In the period 2002–2004 in 2104 pregnant women between 10 + 6 and 13 + 5 weeks' gestation, NT was evaluated as a parameter for aneuploidy screening: out of these, 734 singleton pregnant women that underwent 2nd trimester amniocentesis and whose pregnancy outcome were known were selected. NT was statistically correlated to pregnancy and neonatal outcome. Results Median gestational age (GA) at NT evaluation was 11 + 2 weeks' gestation. NT median was 1.1 mm (0.9–1.4 mm, 25th–75th centile, range 0.5–4.0 mm). After multiple logistic regressions, the variables significantly associated to NT values were: threatened preterm labor (p < 0.008) and preterm labor (p < 0.02). The best diagnostic accuracy point was NT > 95th centile and > 1.5 MoM for the prediction of threatened preterm labor. Conclusion In this series, increased NT values were associated to threatened preterm labor and preterm labor in euploid fetuses: this finding may have clinical consequences in the management of such pregnancies.
Treatment and long-term follow-up of extrahepatic biliary obstruction with bilirubin cholelithiasis in a Somali cat with pyruvate kinase deficiency
Authors: Harvey Andrea M , Holt Peter E , Barr Frances J , Rizzo Francesca , Tasker Séverine
Published: May 2007

A 2-year-old female neutered Somali cat was presented with vomiting and acute onset jaundice 1 year after diagnosis of pyruvate kinase (PK) deficiency. Diagnostic investigations revealed a moderate regenerative haemolytic anaemia, severe hyperbilirubinaemia and elevated liver enzymes. Ultrasonography revealed marked distension of the gall bladder and common bile duct (CBD), consistent with extrahepatic biliary obstruction (EHBO). At cholecystotomy, the gall bladder contained purulent material, and two obstructive choleliths were removed from the CBD by choledochotomy. The cat recovered from surgery uneventfully, and serum liver enzymes and bilirubin normalised within 10 days. Postoperative treatment consisted of cephalexin, metronidazole and ursodeoxycholic acid (UDCA). Bacterial culture of the gall bladder contents yielded a pure growth of an Actinomyces species. Cholelith analysis revealed that they consisted of 100% bilirubin. Antibiotic treatment was stopped 4 weeks after surgery but UDCA was continued indefinitely. The cat remains clinically well with no recurrence of cholelithiasis 20 months after initial presentation. This is the first report of successful treatment and long-term follow-up of a cat with EHBO due to bilirubin cholelithiasis in association with PK deficiency-induced chronic haemolysis.
Retrospective analysis of selected predictors of mortality within a veterinary intensive care unit
Authors: Simpson Kerry E , McCann Theresa M , Bommer Nicholas X , Pereira Yolanda Martinez , Corston Claire , Reed Nicola , Gunn-Moore Danièlle A.
Published: May 2007

The records of 204 cats entering the intensive care unit (ICU) at the University of Edinburgh Small Animal Hospital between December 2002 and October 2006 were retrospectively analysed. Of these, 37 cats over 12 months of age had a systolic blood pressure recorded on entry into the ICU, and this group comprised our study population. Of these 37 cats, 36 had both heart rate and respiratory rate recorded on entry into the ICU, whilst 24 of these cats also had body temperature recorded. The relationship between (i) survival to discharge and (ii) survival until 21 days after admission to the ICU was analysed using univariate generalised linear models with binomial errors. The robustness of any significant relationship was assessed using multivariate analysis methods. In addition, receiver operator curves (ROC) were generated for any of the significant predictors of mortality and from these curves the threshold values, optimal sensitivity and specificity were calculated. Using these values survival curves were generated for any significant prognostic indexes. A decreased blood pressure at the time of admission to the ICU was found to be a significant negative predictor of survival until discharge from the hospital. Overall, a systolic blood pressure of 124 mmHg or higher at the time of admission to the ICU has a sensitivity of 47.8% and a specificity of 85.7% for predicting that a cat will survive until discharge from the hospital.
Evidence of very long meandering features in the logarithmic region of turbulent boundary layers
Authors: HUTCHINS N. , MARUSIC IVAN
Published: May 2007

A regime of very long meandering positive and negative streamwise velocity fluctuations, that we term ‘superstructures’, are found to exist in the log and lower wake regions of turbulent boundary layers. Measurements are made with a spanwise rake of 10 hot-wires in two separate facilities (spanning more than a decade ofReτ) and are compared with existing PIV and DNS results. In all cases, we note evidence of a large-scale stripiness in the streamwise velocity fluctuations. The length of these regions can commonly exceed 20δ. Similar length scales have been previously reported for pipes and DNS channel flows. It is suggested that the true length of these features is masked from single-point statistics (such as autocorrelations and spectra) by a spanwise meandering tendency. Support for this conjecture is offered through the study of a synthetic flow composed only of sinusoidally meandering elongated low- and high-speed regions. From detailed maps of one-dimensional spectra, it is found that the contribution to the streamwise turbulence intensities associated with the superstructures appears to be increasingly significant with Reynolds number, and scales with outer length variables (δ). Importantly, the superstructure maintains a presence or footprint in the near-wall region, seeming to modulate or influence the near-wall cycle. This input of low-wavenumber outer-scaled energy into the near-wall region is consistent with the rise in near-wall streamwise intensities, when scaled with inner variables, that has been noted to occur with increasing Reynolds number. In an attempt to investigate these structures at very high Reynolds numbers, we also report on recent large-scale sonic anemometer rake measurements, made in the neutrally stable atmospheric surface layer. Preliminary results indicate that the superstructure is present in the log region of this atmospheric flow atReτ= 6.6×105, and has a size consistent with outer scaling.
Enhancing the absolute instability of a boundary layer by adding a far-away plate
Authors: HEALEY J. J.
Published: May 2007

When a solid plate, with a boundary condition of no normal flow through it, is introduced parallel to a shear layer it is normally expected to exert a stabilizing influence on any inviscid linearly unstable waves. In this paper we present an example of an absolutely unstable boundary-layer flow that can be made more absolutely unstable by the addition of a plate parallel to the original flow and far from the boundary layer itself. In particular, the addition of the plate is found to increase the growth rate of the absolute instability of the original boundary-layer flow by an order of magnitude for long waves. This phenomenon is illustrated using piecewise-linear inviscid basic-flow profiles, for which analytical dispersion relations have been derived. Long-wave stability theories have been developed in several limits clarifying the mechanisms underlying the behaviour and establishing its generic nature. The class of flows expected to exhibit this phenomenon includes a class found recently to have an exponential growth of disturbances in the wall-normal direction, owing to the approach of certain saddle-points to certain branch-cuts in the complex-wavenumber plane. The theory also suggests that a convectively unstable flow in an infinite domain can be converted, in some circumstances, into an absolutely unstable flow when the domain is made finite by the addition of a plate, however far away the plate is.
Weak, strong and detached oblique shocks in gravity-driven granular free-surface flows
Authors: GRAY J. M. N. T. , CUI X.
Published: May 2007

Hazardous natural flows such as snow-slab avalanches, debris flows, pyroclastic flows and lahars are part of a much wider class of dense gravity-driven granular free-surface flows that frequently occur in industrial processes as well as in foodstuffs in our kitchens! This paper investigates the formation of oblique granular shocks, when the oncoming flow is deflected by a wall or obstacle in such a way as to cause a rapid change in the flow height and velocity. The theory for non-accelerative slopes is qualitatively similar to that of gasdynamics. For a given deflection angle there are three possibilities: a weak shock may form close to the wall; a strong shock may extend across the chute; or the shock may detach from the tip. Weak shocks have been observed in both dense granular free-surface flows and granular gases. This paper shows how strong shocks can be triggered in chute experiments by careful control of the downstream boundary conditions. The resulting downstream flow height is much thicker than that of weak shocks and there is a marked decrease in the downstream velocity. Strong shocks therefore dissipate much more energy than weak shocks. An exact solution for the angle at which the flow detaches from the wedge is derived and this is shown to be in excellent agreement with experiment. It therefore provides a very useful criterion for determining whether the flow will detach. In experimental, industrial and geophysical flows the avalanche is usually accelerated, or decelerated, by the net effect of the gravitational acceleration and basal sliding friction as the slope inclination angle changes. The presence of these source terms necessarily leads to gradual changes in the flow height and velocity away from the shocks, and this in turn modifies the local Froude number of the flow. A shock-capturing non-oscillating central method is used to compute numerical solutions to the full problem. This shows that the experiments can be matched very closely when the source terms are included and explains the deviations away from the classical oblique-shock theory. We show that weak shocks bend towards the wedge on accelerative slopes and away from it on decelerative slopes. In both cases the presence of the source terms leads to a gradual increase in the downstream flow thickness along the wedge, which suggests that defensive dams should increase in height further down the slope, contrary to current design criteria but in accordance with field observations of snow-avalanche deposits from a defensive dam in Northwestern Iceland. Movies are available with the online version of the paper.
Electro-osmotic slip and electroconvective instability
Authors: ZALTZMAN B. , RUBINSTEIN I.
Published: May 2007

Electric conduction from an electrolyte solution into a charge selective solid, such as ion exchange membrane or electrode, becomes unstable when the electrolyte concentration near the interface approaches zero owing to diffusion limitation. The sequence of events leading to instability is as follows: upon the decrease of the interface concentration, the electric double layer at the interface transforms from its common quasi-equilibrium structure to a different, non-equilibrium one. The key feature of this new structure is an extended space charge added to the usual one of the quasi-equilibrium electric double layer. The non-equilibrium electro-osmotic slip related to this extended space charge renders the quiescent conductance unstable. A unified asymptotic picture of the electric double-layer undercurrent, encompassing all regimes from quasi-equilibrium to the extreme non-equilibrium one, is developed and employed for derivation of a universal electro-osmotic slip formula. This formula is used for a linear stability study of quiescent electric conduction, yielding the precise parameter range of instability, compared with that in the full electroconvective formulation. The physical mechanism of instability is traced both kinematically, in terms of non-equilibrium electro-osmotic slip, and dynamically, in terms of forces acting in the electric double layer.
Direct numerical simulation of turbulent Taylor–Couette flow
Authors: BILSON M. , BREMHORST K.
Published: May 2007

Direct numerical simulation (DNS) is used to investigate turbulent Taylor–Couette (TC) flow. A simulation was run for a Reynolds number of 3200 in an apparatus with a radius ratio of η = 0.617 and an aspect ratio of 4.58, which assumed a vortex pair wavelength of 2.29. Results reported include the mean velocity, velocity fluctuation intensities, Reynolds stress budgets, and visualizations of the instantaneous velocity fluctuation field. Secondary near-wall vortex pairs are observed near to the cylinder in addition to the Taylor vortex (TV) motion. Weaker evidence of secondary vortices is found at the outer cylinder where a banded structure has been identified. The azimuthal wall shear stress component shows large peaks and valleys at stagnation points on the surface of both cylinders where flow from neighbouring vortices impacts on the respective wall. These stagnation points correspond to locations where the secondary vortices have been identified. The effect of the mean TV motion is reflected in the Reynolds stress budgets which are similar to but more complex than those of two-dimensional boundary layers. Visualization of the turbulent velocity fluctuations reveals near-wall streaks at the inner cylinder.
Modulated surface waves in large-aspect-ratio horizontally vibrated containers
Authors: VARAS FERNANDO , VEGA JOSÉ M.
Published: May 2007

We consider the harmonic and subharmonic modulated surface waves that appear upon horizontal vibration along the surface of the liquid in a two-dimensional large-aspect-ratio (length large compared to depth) container, whose depth is large compared to the wavelength of the surface waves. The analysis requires us also to consider an oscillatory bulk flow and a viscous mean flow. A weakly nonlinear description of the harmonic waves is made which provides the threshold forcing amplitude to trigger harmonic instabilities, which are of various qualitatively different kinds. A linear analysis provides the threshold amplitude for the appearance of subharmonic waves through a subharmonic instability. The results obtained are used to make several specific qualitative and quantitative predictions.
Bifurcations in shock-wave/laminar-boundary-layer interaction: global instability approach
Authors: ROBINET J.-CH.
Published: May 2007

The principal objective of this paper is to study some unsteady characteristics of an interaction between an incident oblique shock wave impinging on a laminar boundary layer developing on a flat plate. More precisely, this paper shows that some unsteadiness, in particular the low-frequency unsteadiness, originates in a supercritical Hopf bifurcation related to the dynamics of the separated boundary layer. Various direct numerical simulations were carried out of a shock-wave/laminar-boundary-layer interaction (SWBLI). Three-dimensional unsteady Navier–Stokes equations are numerically solved with an implicit dual time stepping for the temporal algorithm and high-order AUSMPW+ scheme for the spatial discretization. A parametric study on the oblique shock-wave angle has been performed to characterize the unsteady behaviour onset. These numerical simulations have shown that starting from the incident shock angle and the spanwise extension, the flow becomes three-dimensional and unsteady. A linearized global stability analysis is carried out in order to specify and to find some characteristics observed in the direct numerical simulation. This stability analysis permits us to show that the physical origin generating the three-dimensional characters of the flow results from the existence of a three-dimensional stationary global instability.
Relaxation of a dewetting contact line. Part 1. A full-scale hydrodynamic calculation
Authors: SNOEIJER JACCO H. , ANDREOTTI BRUNO , DELON GILES , FERMIGIER MARC
Published: May 2007

The relaxation of a dewetting contact line is investigated theoretically in the so-called ‘Landau–Levich’ geometry in which a vertical solid plate is withdrawn from a bath of partially wetting liquid. The study is performed in the framework of lubrication theory, in which the hydrodynamics is resolved at all length scales (from molecular to macroscopic). We investigate the bifurcation diagram for unperturbed contact lines, which turns out to be more complex than expected from simplified ‘quasi-static’ theories based upon an apparent contact angle. Linear stability analysis reveals that below the critical capillary number of entrainment, Cac, the contact line is linearly stable at all wavenumbers. Away from the critical point, the dispersion relation has an asymptotic behaviour σ∝|q| and compares well to a quasi-static approach. Approaching Cac, however, a different mechanism takes over and the dispersion evolves from ∼|q| to the more common ∼q2. These findings imply that contact lines cannot be described using a universal relation between speed and apparent contact angle, but viscous effects have to be treated explicitly.
On the leading nonlinear correction to gravity-wave dynamics
Authors: MILDER D. MICHAEL
Published: May 2007

The principal nonlinear correction to the dynamics of gravity waves on an irrotational fluid is traditionally derived as a non-resonant perturbation solution to the Stokes expansion. When the problem is reformulated in the Hamiltonian description and limited to moderately collimated random waves over infinite depth, the perturbation term assumes a very simple and descriptive form. The sum-frequency component for the surface height is just a bilinear product of the height with the associated scalar strain, and the accompanying term in the potential is half the time derivative of the squared linear height. This solution is exact in one surface dimension and remains quite accurate for long-crested waves in two dimensions, with an error small to second order in the angular spread of constituent wave vectors. It is a natural generalization for random, disordered wave ensembles of the second-order Stokes solution, and its effect is to sharpen the random crests and to flatten the troughs. For wave sets of narrow relative bandwidth the difference-frequency component consists of a negligible elevation term and a non-negligible potential term whose gradient is the surface value of the volume return flow balancing the quadratic wave transport of fluid.
Transition from two-dimensional to three-dimensional magnetohydrodynamic turbulence
Authors: THESS ANDRÉ , ZIKANOV OLEG
Published: May 2007

We report a theoretical investigation of the robustness of two-dimensional inviscid magnetohydrodynamic (MHD) flows at low magnetic Reynolds numbers with respect to three-dimensional perturbations. We use a combination of linear stability analysis and direct numerical simulations to analyse three problems, namely the flow in the interior of a triaxial ellipsoid, and two unbounded flows: a vortex with elliptical streamlines and a vortex sheet parallel to the magnetic field. The flow in a triaxial ellipsoid is found to present an exact analytical model which demonstrates both the existence of inviscid unstable three-dimensional modes and the stabilizing role of the magnetic field. The nonlinear evolution of the flow is characterized by intermittency typical of other MHD flows with long periods of nearly two-dimensional behaviour interrupted by violent three-dimensional transients triggered by the instability. We demonstrate, using the second model, that motion with elliptical streamlines perpendicular to the magnetic field becomes unstable with respect to the elliptical instability once the magnetic interaction parameter falls below a critical magnitude whose value tends to infinity as the eccentricity of the streamlines increases. Furthermore, the third model indicates that vortex sheets parallel to the magnetic field, which are unstable for any velocity and any magnetic field, emit eddies with vorticity perpendicular to the magnetic field. Whether the investigated instabilities persist in the presence of small but finite viscosity, in which case two-dimensional turbulence would represent a singular state of MHD flows, remains an open question.
On long-wave propagation over a fluid-mud seabed
Authors: LIU PHILIP L.-F. , CHAN I-CHI
Published: May 2007

Using the Boussinesq approximation, a set of depth-integrated wave equations for long-wave propagation over a mud bed is derived. The wave motions above the mud bed are assumed to be irrotational and the mud bed is modelled as a highly viscous fluid. The pressure and velocity are required to be continuous across the water–mud interface. The resulting governing equations are differential–integral equations in terms of the depth-integrated horizontal velocity and the free-surface displacement. The effects of the mud bed appear in the continuity equation in the form of a time integral of weighted divergence of the depth-averaged velocity. Damping rates for periodic waves and solitary waves are calculated. For the solitary wave case, the velocity profiles in the water column and the mud bed at different phases are discussed. The effects of the viscous boundary layer above the mud–water interface are also examined.
Optimal growth, model reduction and control in a separated boundary-layer flow using global eigenmodes
Authors: ÅKERVIK ESPEN , HŒPFFNER JÉRÔME , EHRENSTEIN UWE , HENNINGSON DAN S.
Published: May 2007

Two-dimensional global eigenmodes are used as a projection basis both for analysing the dynamics and building a reduced model for control in a prototype separated boundary-layer flow. In the present configuration, a high-aspect-ratio smooth cavity-like geometry confines the separation bubble. Optimal growth analysis using the reduced basis shows that the sum of the highly non-normal global eigenmodes is able to describe a localized disturbance. Subject to this worst-case initial condition, a large transient growth associated with the development of a wavepacket along the shear layer followed by a global cycle related to the two unstable global eigenmodes is found. The flow simulation procedure is coupled to a measurement feedback controller, which senses the wall shear stress at the downstream lip of the cavity and actuates at the upstream lip. A reduced model for the control optimization is obtained by a projection on the least stable global eigenmodes, and the resulting linear-quadratic-Gaussian controller is applied to the Navier–Stokes time integration. It is shown that the controller is able to damp out the global oscillations.
Ablative Rayleigh–Taylor instability with strong temperature dependence of the thermal conductivity
Authors: ALMARCHA C. , CLAVIN P. , DUCHEMIN L. , SANZ J.
Published: May 2007

An asymptotic analysis of Rayleigh–Taylor unstable ablation fronts encountered in inertial confinement fusion is performed in the case of a strong temperature dependence of the thermal conductivity. At leading order the nonlinear analysis leads to a free boundary problem which is an extension of the classical Rayleigh–Taylor instability with unity Atwood number and an additional potential flow of negligible density expelled perpendicular to the front. The nonlinear evolution of the front is analysed in two-dimensional geometry by a boundary integral method. The shape of the front develops a curvature singularity within a finite time, as for the Birkhoff–Rott equation for the Kelvin–Helmholtz instability.
Numerical solutions of the unsteady Fanno model for compressible pipe flow
Authors: NOVIKOVS A. , OCKENDON H. , OCKENDON J. R.
Published: May 2007

This paper presents numerical results on the evolution of the solutions of the Fanno model for compressible pipe flow. The principal results concern the large-time behaviour when nonlinear effects are appreciable throughout the evolution. Our computations show that compression waves can be expected to evolve into travelling waves for large times whereas expansion waves cannot.
Neighbourhood-level effects on psychoses: re-examining the role of context
Authors: KIRKBRIDE JAMES B. , MORGAN CRAIG , FEARON PAUL , DAZZAN PAOLA , MURRAY ROBIN M. , JONES PETER B.
Published: May 2007

Background

The incidence of schizophrenia varies by individual-level characteristics and neighbourhood-level attributes. Few specific socio-environmental risk factors (SERFs) have been identified at the neighbourhood level. Cross-level interactions are poorly understood. We investigated these issues using data from the Aetiology and Ethnicity in Schizophrenia and Other Psychoses (AESOP) study.

Method

All incidence cases of ICD-10 schizophrenia (F20) and other non-affective psychoses (F21–29), aged 16–64 years, across 33 wards in Southeast London were identified over a 2-year period (1997–1999). Census data provided the denominator for each ward. Multilevel Poisson regression simultaneously modelled individual- and neighbourhood-level SERFs, including socio-economic deprivation, voter turnout (proxy for social capital), ethnic fragmentation (segregation) and ethnic density.

Results

A total of 218 subjects were identified during 565 576 person-years at risk. Twenty-three per cent of variance in incidence of schizophrenia across wards could be attributed to neighbourhood-level risk factors [95% confidence interval (CI) 9·9–42·2]. Thus, 1% increases in voter turnout [incidence rate ratio (IRR) 0·95, 95% CI 0·92–0·99] and ethnic segregation (IRR 0·95, 95% CI 0·92–0·99) were both independently associated with a reduced incidence of 5%, independent of age, sex, ethnicity, deprivation and population density. This was similar for other non-affective psychoses. There was some evidence that ethnic minority individuals were at greater risk of schizophrenia in areas with smaller proportions of minority groups (p=0·07).

Conclusion

SERFs at individual and neighbourhood levels were implicated in the aetiology of psychosis, but we were unable to determine whether these associations were causal. Individual risk may be mediated by social capital, which could operate as a protective factor, perhaps moderating social stress in the onset of psychoses.
Clustering of eating disorder symptoms in a general population female twin sample: a latent class analysis
Authors: DUNCAN ALEXIS E. , BUCHOLZ KATHLEEN KEENAN , NEUMAN ROSALIND J. , AGRAWAL ARPANA , MADDEN PAMELA A. F. , HEATH ANDREW C.
Published: May 2007

Background

Previous studies have reported that the current DSM-IV eating disorder (ED) criteria do not adequately describe ED symptomatology. The objective of the current study was to examine the clustering of ED symptoms in a general population sample using latent class analysis (LCA).

Method

ED symptoms from 3723 female young adult twins (mean age 22) were analyzed using LCA, and resulting classes were compared on external validators reflecting ED and other co-morbid psychiatric diagnoses, substance use disorders (SUDs), and suicidality.

Results

The optimal solution consisted of five latent classes characterized as: (1) Unaffected; (2) Low Weight Gain; (3) Weight Concerned; (4) Dieters; and (5) ED. Members of the ED class had significantly higher prevalence of co-morbid psychiatric disorders, SUDs, and suicidality than the Unaffected and Low Weight Gain classes, and elevated rates of suicidality and major depression compared to the Weight Concerned and Dieter classes, which differed from each other primarily in terms of current body mass index (BMI). Dieter class members were more likely to be overweight and obese and less likely to be underweight than Weight Concerned class members. The majority of women with an ED diagnosis were assigned to the ED class, and few differences were found between ED class members with and without an ED diagnosis.

Conclusions

The results add to the evidence that many women with significant ED psychopathology are not being identified by the DSM-IV ED categories.
Differentiation of executive and attention impairments in affective illness
Authors: STODDART SAMUEL D. R. , CRADDOCK NICK J. , JONES LISA A.
Published: May 2007

Background

Executive impairments have been reported in affective illness, but the influence of attention on executive performance has not been fully considered. The purpose of this study was to investigate whether executive impairments in affective illness were independent of attention impairments, and whether independent executive impairments were specific to bipolar (BP) affective illness.

Method

Forty-two individuals with major affective disorders [20 unipolar (UP) depression and 22 BP disorder] were compared with 40 healthy controls on measures of attention and executive function. None of the patients were currently experiencing an episode of affective illness.

Results

As expected, both UP and BP patient groups showed significant neuropsychological impairments relative to controls. Significant differences in performance on executive function measures were also observed between UP and BP patients, even after the influence of attention had been taken into account. These impairments were not attributable to current levels of affective symptomatology or to medication.

Conclusions

A single neuropsychological dissociation appears to be present between UP and BP affective illness, with BP individuals showing a specific executive deficit that is independent of attention impairment on the Hayling Sentence Completion Test (HSCT).
Signatures of Enceladus in Saturn's E ring
Authors: Juhász Antal , Horányi Mihály , Morfill Gregor E.
Published: May 2007

Dust production from Enceladus has long been suggested as the main source of dust in Saturn's E ring. This was supported by the observation that the ring's optical depth peaks close to the orbit of this moon. However, both HST and Keck observations indicated that the peak of the optical depth distribution in fact lies outside the orbit of Enceladus, with a displacement of approximately 104 km. Though this outward shift has been suspected to be a result of electromagnetic forces, it could not be reproduced in earlier studies. Here we show that it is intimately related to the initial inclinations of the grains produced in the recently discovered plumes. For grains with radii rg > 0.5 μm, the small initial inclination greatly reduces their re‐collision probability, allowing for sufficiently long lifetimes for plasma drag to transport them outwards. Our numerical results can also be used in the simultaneous interpretation of the measurements by the Cassini CDA, RPWS instruments and imaging.
Variability and Fractal Analysis of Middle Cerebral Artery Blood Flow Velocity and Arterial Blood Pressure in Subarachnoid Hemorrhage
Authors: Soehle Martin , Czosnyka Marek , Chatfield Doris A , Hoeft Andreas , Peña Alonso
Published: May 2007

Higher biologic systems operate far from equilibrium resulting in order, complexity, fluctuation of inherent parameters, and dissipation of energy. According to the decomplexification theory, disease is characterized by a loss of system complexity. We analyzed such complexity in patients after subarachnoid hemorrhage (SAH), by applying the standard technique of variability analysis and the novel method of fractal analysis to middle cerebral artery blood flow velocity (FV) and arterial blood pressure (ABP). In 31 SAH –patients, FV (using transcranial Doppler sonography) and direct ABP were measured. The standard deviations (s.d.) and coefficients of variation (CV = relative s.d.) for FV and ABP time series of length 210 secs were calculated as measures of variability. The spectral index βlow and the Hurst coefficient HbdSWV were analyzed as fractal measures. Outcome was assessed 1 year after SAH according to the Glasgow Outcome Scale (GOS). Both FV (βlow = 2.2±0.4, mean±s.d.) and ABP (βlow = 2.3±0.4) were classified as nonstationary (fractal Brownian motion) signals. FV showed significantly ( P <0.05) higher variability (CV = 7.2±2.5%) and Hurst coefficient ( HbdSWV = 0.26±0.13) as compared with ABP (CV = 5.5±2.7%, HbdSWV = 0.19±0.11). Better outcome (GOS) correlated significantly ( P <0.05) with higher s.d. of FV (Spearman's rs = 0.51, rs2 = 0.26) and ABP ( rs = 0.57, rs2 = 0.32), as well as with a higher Hurst coefficient of ABP ( rs = 0.46, rs2 = 0.21). Cerebral vasospasm reduced CV of FV, but left HbdSWV unchanged. FV and ABP fluctuated markedly despite homeostatic control. A reduced variability of FV and ABP might indicate a loss of complexity and was associated with a less favorable outcome. Therefore, the decomplexification theory of illness may apply to SAH.
Kinetic effects in a Hall thruster discharge
Authors: Kaganovich I. D. , Raitses Y. , Sydorenko D. , Smolyakov A.
Published: May 2007

Recent analytical studies and particle-in-cell simulations suggested that the electron velocity distribution function in E×B discharge of annular geometry Hall thrusters is non-Maxwellian and anisotropic. The average kinetic energy of electron motion in the direction parallel to the thruster channel walls (across the magnetic field) is several times larger than that in the direction normal to the walls. Electrons are stratified into several groups depending on their origin (e.g., plasma or channel walls) and confinement (e.g., lost on the walls or trapped in the plasma). Practical analytical formulas are derived for the plasma flux to the wall, secondary electron fluxes, plasma potential, and electron cross-field conductivity. Calculations based on these formulas fairly agree with the results of numerical simulations. The self-consistent analysis demonstrates that the elastic electron scattering in collisions with atoms and ions plays a key role in formation of the electron velocity distribution function and the plasma potential with respect to the walls. It is shown that the secondary electron emission from the walls may significantly enhance the electron conductivity across the magnetic field but only weakly affects the insulating properties of the near-wall sheath. Such self-consistent decoupling between the secondary electron emission effects on the electron energy losses and the electron cross-field transport is currently not captured by the existing fluid and hybrid models of Hall thrusters.
A three-dimensional model of single-electron tunneling between a conductive probe and a localized electronic state in a dielectric
Authors: Zheng N. , Williams C. C. , Mishchenko E. G. , Bussmann E.
Published: May 2007

Motivated by recent measurements of force detected single-electron tunneling, we present a three-dimensional model for the tunneling rate between a metallic tip and a localized electronic state in a dielectric surface. The tip is assumed to be semi-infinite, with electron wave functions approximated by plane waves. A localized electron state in the dielectric sample is approximated by a spherical quantum well. The tunneling rate is obtained with the help of Bardeen’s approach and is compared with the results for a one-dimensional square barrier model. A comparison with experimental data is also presented.
Fe valence states and ferromagnetism occurring in reduced anatase Ti0.97Fe0.03O2−δ
Authors: Lee Hi Min , Kim Chul Sung
Published: May 2007

Fe-doped anatase TiO2 polycrystalline films and powders have been prepared by the sol-gel method. Air-annealed film shows paramagnetic behavior at room temperature. However, when the film is further annealed in a vacuum, the ferromagnetic properties are strongly enhanced with the magnetic moment of 0.42μB∕Fe at 5kOe. Mössbauer spectrum of air-annealed film at 295K shows a single doublet of Fe3+. On the other hand, the absorption spectrum after vacuum annealing exhibits two doublets, in which one is the same component with air-annealed case and the other is a new doublet corresponding to Fe2+ state. The temperature dependence of absorption linewidth and quadrupole splitting for the Fe2+ doublet indicates that Fe2+ ions are not paramagnetic and their magnetic interaction exists also at 295K.
Optical head with a butted-grating structure that generates a subwavelength spot for laser-assisted magnetic recording
Authors: Tawa Fumihiro , Hasegawa Shin-ya , Odajima Wataru
Published: May 2007

Laser-assisted magnetic recording uses a subwavelength laser spot as its heat source. We devised a planar-type multilayer optical head with a butted-grating structure that combines dielectric materials. In this optical head, the spot size in the Y direction was reduced using a butted-grating structure, and the spot size in the X direction was reduced by multimode interference with the transmitted light. As a calculated result, a subwavelength spot of 88×82nm2 [full width at half maximum (FWHM)] at an optical efficiency of 17% is obtained. We experimentally demonstrated the subwavelength spot of 88×60nm2 (FWHM) by scanning near-field optical microscope.
Analysis of steplike change of impedance for thin-film giant magnetoimpedance element with inclined stripe magnetic domain based on magnetic energy
Authors: Nakai T. , Ishiyama K. , Yamasaki J.
Published: May 2007

The phenomenon of steplike impedance change for thin-film giant magnetoimpedance (GMI) element was reported. The steplike change happens simultaneously with the appearance or the disappearance of stripe magnetic domain. This phenomenon is obtained for amorphous Co85Nb12Zr3 soft magnetic thin film in a rectangle shape with an in-plane uniaxial easy axis in the direction nearly 60° against the short-side axis of the element. The steplike change of impedance appears in a certain magnitude of external magnetic field. A high-sensitive magnetic field sensor can be realized by applying this phenomenon. In this study, a mechanism of the appearance or the disappearance of inclined stripe magnetic domain is discussed based on an analysis of magnetic domain energy, for the purpose of applying to a high-sensitivity magnetic field sensor. We assume these extremely different magnetic domains as (I) stripe domain with closure domain and (II) single domain, based on experimentally observed domain structures. The result of analysis shows that the magnetic energy of these two phases intersects each other in a certain external magnetic field, which means that the basis of steplike GMI of thin-film element is revealed as a structural change of magnetic domain based on magnetic energy.
Influence of IrMn exchange bias layer on the magnetic properties of half-ring NiFe micron structures
Authors: Chang L. J. , Chen A. L. , Cheng K. W. , Yu C. , Lee S. F. , Liou Y. , Yao Y. D.
Published: May 2007

The magnetization reversal behavior in half-ring NiFe structures and the influence of IrMn exchange bias layer was studied in this experiment. Two-step switching behavior, as in the ring shape, was observed when external field was in the short axis for single half-ring films. For NiFe–IrMn double layer structures, the unidirection anisotropy could be controlled by field cooling the samples. The exchange field strength did not follow a cosine curve when the external field was rotated in the sample plane. It could be attributed to the competition between the shape and the exchange anisotropies. When the strength of exchange field was strong, a single-step switching was observed. Two-step switching was retained for weaker exchange coupling.
Strongly enhanced thermal expansion of low-dimensional itinerant weak antiferromagnets near the quantum critical points
Authors: Konno Rikio , Takahashi Yoshinori , Nakano Hiroki
Published: May 2007

The thermal expansion of low-dimensional itinerant antiferromagnetic metals is discussed along with the recent study on the magneto-volume effect by Takahashi and Nakano [J. Phys.: Condens. Matter 16, 4505 (2004)]. In this study, we find that the thermal volume expansion derived by Takahashi and Nakano shows a stronger enhancement of the T-linear slope of the thermal expansion coefficient proportional to y−1∕2 and ln(1∕y), respectively, for one-dimensional and two-dimensional (2D) systems than that of three dimensions as we approach the magnetic instability point (y→0), where y is the inverse of the reduced staggered magnetic susceptibility. On the other hand, the same coefficient for the conventional term by Moriya and Usami [Solid State Commun. 34, 95 (1980)] is suppressed proportional to 1∕ln(1∕y) for 2D systems. The present result suggests that the temperature dependence of low-dimensional weak antiferromagnets is generally dominated by the strongly enhanced T2-linear thermal expansion from the magnetic origin.
Streaming potential generated by two-phase flow in a capillary
Authors: Sherwood J. D.
Published: May 2007

The streaming potential generated by pressure-driven two-phase flow in a circular capillary differs from that generated by single-phase flow. Three model problems are considered, in which the dispersed phase consists of either (i) a rigid spherical particle (possibly charged), (ii) an uncharged spherical bubble, and (iii) a long, uncharged Bretherton bubble. In all three cases, the particle or bubble is assumed to lie on the center line of the capillary tube, so that the problem is axisymmetric, and is assumed to be of almost the same diameter as the internal diameter of the capillary, so that lubrication theory can be used. The electrical potentials on the surface of the particle and on the walls of the capillary are ζp and ζc, respectively, and the Debye length is assumed much smaller than the gap between the particle and the walls of the capillary. If the flow rate is held constant, the presence of the rigid particle increases the pressure drop between the ends of the capillary, and also changes the streaming potential by an amount proportional to ζc−ζp. This change in potential will in general be small compared to the total streaming potential developed between the two ends of a long capillary. However, if the capillary is filled with a large number of rigid particles, not only will the changes in pressure drop and streaming potential between the two ends of the capillary be large, but there will be a significant change in the coefficient of proportionality between pressure drop and streaming potential. The presence of an uncharged spherical bubble or Bretherton bubble changes the pressure drop between the ends of the capillary (for a given flow rate) but does not change the linear relation between pressure drop and streaming potential. However, the linear relation between flow rate and streaming potential is modified for the spherical bubble, and becomes nonlinear when a Bretherton bubble is present.
Electrical response of Pd∕AlN∕6H−SiC and Pd∕AlN∕3C−SiC devices to hydrogen gas: The effects of AlN layer
Authors: Rahman Md H. , Thakur J. S. , Rimai L. , Auner G. W. , Naik R. , Chaudhury Zariff A. , Newaz G.
Published: May 2007

The electrical response characteristics of Pd∕AlN∕6H−SiC and Pd∕AlN∕3C−SiC devices to hydrogen gas have been investigated. An AlN film, with a thickness of 100 nm, was deposited simultaneously on 6H−SiC(0001) and 3C−SiC(001) substrates. The structural, morphological, and microstructural characterizations of these devices were carried out using x-ray diffraction, atomic force microscopy, and transmission electron microscopy techniques. In both the cases, the AlN film showed a highly textured c axis growth with a wurtzite crystal structure. However, the surface roughness of the AlN film on 3C–SiC was larger by a factor of three compared to that deposited on 6H–SiC, with an associated increase in the value of dielectric constant of AlN. Theoretical analysis of the electrical characteristics suggests that, in addition to the physical properties of the semiconducting layer, the dielectric constant of AlN layer directly influences the electrical response of the device to hydrogen. The Pd∕AlN∕3C−SiC device showed a consistently reduced electrical response to hydrogen compared to the Pd∕AlN∕6H−SiC device.
Two types of multicomponent matrix loop algebras and its application
Authors: Dong Huanhe , Yuan Wei
Published: May 2007

Two types of multicomponent matrix Lie algebras are constructed, which are devoted to obtain two types of new loop algebras ÃM−1. By making use of Tu scheme, integrable multicomponent Levi hierarchy and multicomponent Ablowitz-Kaup-Newell-Segur (AKNS) hierarchy are generated, which contain an arbitrary positive integer M. Furthermore, we expanded the multicomponent matrix loop algebra into a large one and work out integrable coupling of Levi hierarchy and AKNS hierarchy. This method proposed in this paper can be used generally.
Vortical flow control on a conical fore body cross section using an array of pulsed dc actuators
Authors: Singh Kunwar Pal , Roy Subrata
Published: May 2007

Flow control on a conical fore body cross section of an aircraft is studied using plasma discharge by considering the neutral gas flow at 17.5 deg angle of attack. The equations governing the motion of electrons, ions as well as Poisson’s equation are solved together with Navier-Stokes and energy equation for neutrals to study flow control. A single barrier discharge actuator is not sufficient to control the flow on the entire length of the fore body. An arrangement of multiple electrodes powered with pulsed dc voltage has been suggested for controlling such flows. The effects of joule heating of plasma, dielectric heating, and electrodynamic force have been investigated, separately and then combined on flow control. It is found that joule heating results in high temperature of the dielectric surface, however; electrodynamic force contributes prominently to flow control. A three-dimensional analysis is necessary to validate results with experiments.