bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical study of vertical dispersion by stratified turbulence
Authors: BRETHOUWER G. , LINDBORG E.
Published: July 2009

Numerical simulations are carried out to investigate vertical fluid particle dispersion in uniformly stratified stationary turbulent flows. The results are compared with the analysis of Lindborg & Brethouwer (J. Fluid Mech., vol. 614, 2008, pp. 303–314), who derived long- and short-time relations for the mean square vertical displacement 〈δz〉 of fluid particles. Several direct numerical simulations (DNSs) with different degrees of stratification and different buoyancy Reynolds numbers are carried out to test the long-time relation 〈δz2〉 = 2ϵPt/N2. Here, ϵP is the mean dissipation of turbulent potential energy; N is the Brunt–Väisälä frequency; and t is time. The DNSs show good agreement with this relation, with a weak dependence on the buoyancy Reynolds number. Simulations with hyperviscosity are carried out to test the relation 〈δz2〉 = (1+πCPL)2ϵPt/N2, which should be valid for shorter time scales in the range N−1 ≪ t ≪ T, where T is the turbulent eddy turnover time. The results of the hyperviscosity simulations come closer to this prediction with CPL about 3 with increasing stratification. However, even in the simulation with the strongest stratification the growth of 〈δz2〉 is somewhat slower than linear in this regime. Based on the simulation results it is argued that the time scale determining the evolution of 〈δz2〉 is the eddy turnover time, T, rather than the buoyancy time scale N−1, as suggested in previous studies. The simulation results are also consistent with the prediction of Lindborg & Brethouwer (2008) that the nearly flat plateau of 〈δz2〉 observed at t ~ T should scale as 4EP/N2, where EP is the mean turbulent potential energy.
Swimming due to transverse shape deformations
Authors: KANSO EVA
Published: July 2009

Balance laws are derived for the swimming of a deformable body due to prescribed shape changes and the effect of the wake vorticity. The underlying balances of momenta, though classical in nature, provide a unifying framework for the swimming of three-dimensional and planar bodies and they hold even in the presence of viscosity. The derived equations are consistent with Lighthill's reactive force theory for the swimming of slender bodies and, when neglecting vorticity, reduce to the model developed in Kanso et al. (J. Nonlinear Sci., vol. 15, 2005, p. 255) for swimming in potential flow. The locomotion of a deformable body is examined through two sets of examples: the first set studies the effect of cyclic shape deformations, both flapping and undulatory, on the locomotion in potential flow while the second examines the effect of the wake vorticity on the net locomotion. In the latter, the vortex wake is modelled using pairs of point vortices shed periodically from the tail of the deformable body.
AC electrohydrodynamic instabilities in thin liquid films
Authors: ROBERTS SCOTT A. , KUMAR SATISH
Published: July 2009

When DC electric fields are applied to a thin liquid film, the interface may become unstable and form a series of pillars. In this paper, we apply lubrication theory to examine the possibility of using AC electric fields to exert further control over the size and shape of the pillars. For perfect dielectric films, linear stability analysis shows that the influence of an AC field can be understood by considering an effective DC field. For leaky dielectric films, Floquet theory is applied to carry out the linear stability analysis, and it reveals that high frequencies may be used to inhibit the accumulation of interfacial free charge, leading to a lowering of growth rates and wavenumbers. Nonlinear simulations confirm the results of the linear stability analysis while also uncovering additional mechanisms for tuning overall pillar height and width. The results presented here may be of interest for the controlled creation of surface topographical features in applications such as patterned coatings and microelectronics.
Large-eddy simulation and wall modelling of turbulent channel flow
Authors: CHUNG D. , PULLIN D. I.
Published: July 2009

We report large-eddy simulation (LES) of turbulent channel flow. This LES neither resolves nor partially resolves the near-wall region. Instead, we develop a special near-wall subgrid-scale (SGS) model based on wall-parallel filtering and wall-normal averaging of the streamwise momentum equation, with an assumption of local inner scaling used to reduce the unsteady term. This gives an ordinary differential equation (ODE) for the wall shear stress at every wall location that is coupled with the LES. An extended form of the stretched-vortex SGS model, which incorporates the production of near-wall Reynolds shear stress due to the winding of streamwise momentum by near-wall attached SGS vortices, then provides a log relation for the streamwise velocity at the top boundary of the near-wall averaged domain. This allows calculation of an instantaneous slip velocity that is then used as a ‘virtual-wall’ boundary condition for the LES. A Kármán-like constant is calculated dynamically as part of the LES. With this closure we perform LES of turbulent channel flow for Reynolds numbers Reτ based on the friction velocity uτ and the channel half-width δ in the range 2 × 103 to 2 × 107. Results, including SGS-extended longitudinal spectra, compare favourably with the direct numerical simulation (DNS) data of Hoyas & Jiménez (2006) at Reτ = 2003 and maintain an O(1) grid dependence on Reτ.
An experimental study of an axisymmetric turbulent pulsed air jet
Authors: CHOUTAPALLI I. , KROTHAPALLI A. , ARAKERI J. H.
Published: July 2009

An experimental study is carried out to elucidate the structure of a high Reynolds number (~105) turbulent pulsed jet. Particle image velocimetry measurements showed that the near flow field is dominated by a series of vortex rings with jet-like flows in between. The data show that the vortex rings convect at nearly constant speed of 0.6Uj(Uj: mean jet exit velocity) and the spacing between the rings assumes a value of about 0.6/St(St: Strouhal number=fd/Uj, wherefis the pulsing frequency anddis the nozzle exit diameter). With increasing Strouhal number, the rings are closely spaced and the flow tends to assume a steady jet character at five diameters downstream of the nozzle exit. At lower Strouhal numbers there is a distinct region of jet flow in between the rings. Many of the global characteristics, entrainment, mass and momentum flux are essentially determined by the strength and spacing of the rings which, in turn, depend onSt. We show that the increase in momentum is due to both increased momentum flux and overpressure at the exit in accordance with Krueger & Gharib (AIAA J., vol. 43 (4), 2005, p. 792). This increase in momentum comes at the expense of higher energy required to produce the jet. We also present results of organized and random components of the fluctuations and production of the random turbulence in a pulsed jet. The two regions of dominant turbulence production are identified with the ring and the trailing jet shear layers.
Mid-gap invasion in two-layer slot coating
Authors: NAM JAEWOOK , CARVALHO MARCIO S.
Published: July 2009

Multi-layer, continuous liquid coating is the most efficient way to manufacture films that require more than one layer for optimal performance. Dual-layer slot coating is one of different coating methods largely used to deposit two thin, uniform liquid layers on to a moving substrate. The two liquid phases are separated by an inter-layer that starts at the separation point (or line, in three dimensions) attached to the die surface. The stability of the two-phase flow and the location of the separation point are directly related to the quality of the final product. Ideally, the separation point should be attached to the downstream corner of the mid die piece of a dual slot-coating die. However, its location may change as operating conditions vary, leading to undesired flow states, with microvortices and periodic oscillation. The movement of the separation point from its desired location along the die surface is usually referred to as mid-gap invasion and can be associated with the onset of coating defects. It is crucial to determine the set of flow conditions at which it occurs. We study the evolution of the separation-point location and the inter-layer configuration as a function of operating conditions by flow visualization and by solving the two-dimensional Navier–Stokes equation for free-surface flows. The results reveal two different mechanisms for mid-gap invasion, depending on the viscosity ratio of the two liquid layers. They also show that the most critical parameter responsible for the onset of mid-gap invasion is the bottom-layer wet thickness (flow rate). Although the movement of the separation point involves an evolution of complex flow states, a simple but accurate criterion based on rectilinear flow approximation is proposed.
Time-dependent water-wave scattering by arrays of cylinders and the
approximation of near trapping
Authors: MEYLAN MICHAEL H. , TAYLOR RODNEY EATOCK
Published: July 2009

We consider the solution in the time domain of water-wave scattering by arrays of
bottom-mounted cylinders. It has already been shown that near trapping occurs
for certain arrangements of cylinders and we are especially focused on this
phenomenon. We begin with the well-known single-frequency solution to the
problem of a group of cylinders, and the extension of this solution to complex
frequencies. It has been shown that singularities (scattering frequencies or
resonances) occur for certain values of the complex frequency and these
singularities are associated with the near-trapped mode. We show that it is
possible to approximate the solution near these singularities, and produce a
modal shape which is associated with the near-trapped mode. We then consider the
time-dependent problem, beginning with the well-known incident plane wave packet
solution. We also show how the problem of an arbitrary initial displacement can
be found using the single-frequency solutions. This latter result relies on a
special inner product which gives a generalized eigenfunction expansion (because
the operator has a continuous spectrum). We then consider the approximation of
the time-dependent motion using special mode shapes associated with the
scattering frequencies. This approximation relies on the scattering frequencies
lying close to the real axis. We present numerical results which show that this
approximation is accurate for sufficiently large time.
Ethmoid silent sinus syndrome causing inward displacement of the orbit: case report
Authors: McArdle B , Perry C
Published: July 2009

Objective:

We describe a previously unreported case of ethmoid silent sinus syndrome.

Method:

Case report and review of the world literature regarding silent sinus syndrome.

Results:

A 33-year-old woman developed medial displacement of the left orbital contents in the absence of trauma, surgery or other significant pathology. Imaging showed opacification of the left ethmoid sinus and implosion of the medial orbital wall. Previously reported cases of silent sinus syndrome have all involved the maxillary sinus, with subsequent implosion of the orbital floor. Computed tomography scans of our patient showed wide, flat ethmoidal bulla and surrounding cells, with few horizontal bony septae reinforcing the area of collapse.

Conclusion:

This case represents the first report of ethmoid silent sinus syndrome. We argue that, in anatomically susceptible individuals, the silent sinus syndrome can present due to chronic ethmoidal sinusitis.
Cascades in decaying three-dimensional electron magnetohydrodynamic turbulence
Authors: WAREING CHRISTOPHER J. , HOLLERBACH RAINER
Published: July 2009

Decaying electron magnetohydrodynamic (EMHD) turbulence in three dimensions is studied via high-resolution numerical simulations. The resulting energy spectra asymptotically approach a k−2 law with increasing RB, the ratio of the nonlinear to linear time scales in the governing equation, consistent with theoretical predictions. No evidence is found of a dissipative cutoff, consistent with non-local spectral energy transfer and recent studies of 2D EMHD turbulence. Dissipative cutoffs found in previous studies are explained as artificial effects of hyperdiffusivity. In another similarity to 2D EMHD turbulence, relatively stationary structures are found to develop in time, rather than the variability found in ordinary or MHD turbulence. Further, cascades of energy in 3D EMHD turbulence are found to be suppressed in all directions under the influence of a uniform background field. Energy transfer is further reduced in the direction parallel to the field, displaying scale-dependent anisotropy. Finally, the governing equation is found to yield a weak inverse cascade, at least partially transferring magnetic energy from small to large scales.
Effect of electric field emission on charging of dust particles in a plasma
Authors: SODHA MAHENDRA SINGH , DIXIT AMRIT , PRAKASH GYAN
Published: July 2009

The authors have considered the charging of spherical particles in a plasma, taking into account the electric field emission of electrons from the dust particles and the change in the electron/ion densities in the plasma. The dependence of the charge of a particle and electron/ion densities on the radius and number of dust particles and the density of electrons/ions and the temperature in the undisturbed plasma has been studied numerically without and with the inclusion of the electric field emission of electrons from the particles. It is seen that both the electric field emission and the electron/ion kinetics significantly affect the charging process.
Does hypocortisolism predict a poor response to cognitive behavioural therapy in chronic fatigue syndrome?
Authors: Roberts A. D. L. , Charler M.-L. , Papadopoulos A. , Wessely S. , Chalder T. , Cleare A. J.
Published: July 2009

Background

There is evidence that patients with chronic fatigue syndrome (CFS) have mild hypocortisolism. The clinical significance of this is unclear. We aimed to determine whether hypocortisolism exerted any effect on the response of CFS to cognitive behavioural therapy (CBT).

Method

We measured 24-h urinary free cortisol (UFC) in 84 patients with Centers for Disease Control and Prevention (CDC)-defined CFS (of whom 64 were free from psychotropic medication) who then received CBT in a specialist, tertiary out-patient clinic as part of their usual clinical care. We also measured salivary cortisol output from 0800 to 2000 h in a subsample of 56 psychotropic medication-free patients.

Results

Overall, 39% of patients responded to CBT after 6 months of treatment. Lower 24-h UFC output was associated with a poorer response to CBT but only in psychotropic medication-free patients. A flattened diurnal profile of salivary cortisol was also associated with a poor response to CBT.

Conclusions

Low cortisol is of clinical relevance in CFS, as it is associated with a poorer response to CBT. Hypocortisolism could be one of several maintaining factors that interact in the persistence of CFS.
Psychiatric family history and schizophrenia risk in Denmark: which mental disorders are relevant?
Authors: Mortensen P. B. , Pedersen M. G. , Pedersen C. B.
Published: July 2009

Background

A family history of schizophrenia is the strongest single indicator of individual schizophrenia risk. Bipolar affective disorder and schizo-affective disorders have been documented to occur more frequently in parents and siblings of schizophrenia patients, but the familial occurrence of the broader range of mental illnesses and their role as confounders have not been studied in large population-based samples.

Method

All people born in Denmark between 1955 and 1991 (1.74 million) were followed for the development of schizophrenia (9324 cases) during 28 million person-years at risk. Information of schizophrenia in cohort members and psychiatric history in parents and siblings was established through linkage with the Danish Psychiatric Central Register. Data were analysed using log-linear Poisson regression.

Results

Schizophrenia was, as expected, strongly associated with schizophrenia and related disorders among first-degree relatives. However, almost any other psychiatric disorder among first-degree relatives increased the individual's risk of schizophrenia. The population attributable risk associated with psychiatric family history in general was 27.1% whereas family histories including schizophrenia only accounted for 6.0%. The general psychiatric family history was a confounder of the association between schizophrenia and urbanization of place of birth.

Conclusions

Clinically diagnosed schizophrenia is associated with a much broader range of mental disorders in first-degree relatives than previously reported. This may suggest risk haplotypes shared across many disorders and/or shared environmental factors clustering in families. Failure to take the broad range of psychiatric family history into account may bias results of all risk-factor studies of schizophrenia.
Hostility and depressive mood: results from the Whitehall II prospective cohort study
Authors: Nabi H. , Singh-Manoux A. , Ferrie J. E. , Marmot M. G. , Melchior M. , Kivimäki M.
Published: July 2009

Background

The psychosocial vulnerability model of hostility posits that hostile individuals, given their oppositional attitudes and behaviours, are more likely to have increased interpersonal conflicts, lower social support, more stressful life events (SL-E) and higher likelihood of depression. However, little research has tested this hypothesis using large-scale prospective samples. The present study aims to assess the predictive value of hostility for depressive mood.

Method

Data are from 3399 participants in the Whitehall II cohort study, aged 35–55 years at baseline (phase 1 1985–1988). Cynical hostility was measured at phase 1. Depressive mood was assessed at phase 7 (2002–2004). Sociodemographic characteristics, health-related behaviours, common mental disorders and antidepressant medication intake were assessed at phase 1. SL-E and confiding/emotional support were measured at phases 1, 2 (1989–1990) and 5 (1997–1999).

Results

Compared with participants in the lowest quartile of cynical hostility, those in the highest quartiles were more likely to have depressive mood [second quartile: odds ratio (OR) 1.58, 95% confidence interval (CI) 1.14–2.20; third quartile: OR 2.78, 95% CI 2.03–3.77; fourth quartile: OR 4.66, 95% CI 3.41–6.36] in analysis adjusted for sociodemographic characteristics. This graded association was somewhat attenuated (⩽18%) but remained robust to adjustments for the covariates measured at baseline and follow-up. The association was also evident in participants free of mental health difficulties at baseline.

Conclusions

Cynical hostility is a strong and robust predictor of depressive mood. Consideration of personality characteristics may be crucial to the understanding and management of depression.
Dyadic discord at baseline is associated with lack of remission in the acute treatment of chronic depression
Authors: Denton W. H. , Carmody T. J. , Rush A. J. , Thase M. E. , Trivedi M. H. , Arnow B. A. , Klein D. N. , Keller M. B.
Published: July 2009

Background

Dyadic discord, while common in depression, has not been specifically evaluated as an outcome predictor in chronic major depressive disorder. This study investigated pretreatment dyadic discord as a predictor of non-remission and its relationship to depressive symptom change during acute treatment for chronic depression.

Method

Out-patients with chronic depression were randomized to 12 weeks of treatment with nefazodone, the Cognitive Behavioral Analysis System of Psychotherapy or their combination. Measures included the Marital Adjustment Scale (MAS) and the Inventory of Depressive Symptomatology – Self Report (IDS-SR30). Of 681 original patients, 316 were partnered and 171 of these completed a baseline and exit MAS, and at least one post-baseline IDS-SR30. MAS scores were analysed as continuous and categorical variables (‘dyadic discord’ v. ‘no dyadic discord’ defined as an MAS score >2.36. Remission was defined as an IDS-SR30 of ⩽14 at exit (equivalent to a 17-item Hamilton Rating Scale for Depression of ⩽7).

Results

Patients with dyadic discord at baseline had lower remission rates (34.1%) than those without dyadic discord (61.2%) (all three treatment groups) (χ2=12.6, df=1, p=0.0004). MAS scores improved significantly with each of the treatments, although the change was reduced by controlling for improvement in depression. Depression remission at exit was associated with less dyadic discord at exit than non-remission for all three groups [for total sample, 1.8 v. 2.4, t(169)=7.3, p<0.0001].

Conclusions

Dyadic discord in chronically depressed patients is predictive of a lower likelihood of remission of depression. Couple therapy for those with dyadic discord may increase remission rates.
Zero-entropy invariant measures for skew product diffeomorphisms
Authors: SUN PENG
Published: July 2009

In this paper, we study some skew product diffeomorphisms with non-uniformly hyperbolic structure along fibers and show that there is an invariant measure with zero entropy which has atomic conditional measures along fibers. For such diffeomorphisms, our result gives an affirmative answer to the question posed by Herman as to whether a smooth diffeomorphism of positive topological entropy would fail to be uniquely ergodic. The proof is based on some techniques that are analogous to those developed by Pesin and Katok, together with an investigation of certain combinatorial properties of the projected return map on the base.
Extreme-value distributions for some classes of non-uniformly partially hyperbolic dynamical systems
Authors: GUPTA CHINMAYA
Published: July 2009

In this note, we obtain verifiable sufficient conditions for the extreme-value distribution for a certain class of skew-product extensions of non-uniformly hyperbolic base maps. We show that these conditions, formulated in terms of the decay of correlations on the product system and the measure of rapidly returning points on the base, lead to a distribution for the maximum of Φ(p)=−log(d(p,p0)) that is of the first type. In particular, we establish the type I distribution for S1 extensions of piecewise C2 uniformly expanding maps of the interval, non-uniformly expanding maps of the interval modeled by a Young tower, and a skew-product extension of a uniformly expanding map with a curve of neutral points.
Invariant measures on stationary Bratteli diagrams
Authors: BEZUGLYI S. , KWIATKOWSKI J. , MEDYNETS K. , SOLOMYAK B.
Published: July 2009

We study dynamical systems acting on the path space of a stationary (non-simple) Bratteli diagram. For such systems we give an explicit description of all ergodic probability measures that are invariant with respect to the tail equivalence relation (or the Vershik map); these measures are completely described by the incidence matrix of the Bratteli diagram. Since such diagrams correspond to substitution dynamical systems, our description provides an algorithm for finding invariant probability measures for aperiodic non-minimal substitution systems. Several corollaries of these results are obtained. In particular, we show that the invariant measures are not mixing and give a criterion for a complex number to be an eigenvalue for the Vershik map.
Normalisation holomorphe de structures de Poisson
Authors: LOHRMANN PHILIPP
Published: July 2009

We show that a Poisson structure whose linear part vanishes can be holomorphically normalized in a neighbourhood of its singular point $0\in \Bbb C^n$ if, on the one hand, a Diophantine condition on a Lie algebra associated to the quadratic part is satisfied and, on the other hand, the normal form satisfies some formal conditions.
Mixing properties of numeration systems coming from weighted substitutions
Authors: KAMAE TETURO
Published: July 2009

A weighted substitution is a substitution that has weights associated with each occurrence of the substituted symbols. It defines a tiling space that admits the translation and scaling operators; the translation is the additive ℝ-action and the scaling is the multiplicative G-action, where G is a closed multiplicative subgroup of ℝ+. We obtained necessary and sufficient conditions for the additive action to be strongly mixing and for it to be weakly mixing.
Electrical explosion process and amorphous structure of carbon fibers under high-density current pulse igniting intense electron-beam accelerator
Authors: Li Limin , Liu Lie , Cheng Guoxin , Chang Lei , Wan Hong , Wen Jianchun
Published: July 2009

The development of pulsed power technology, particularly for inductive energy storage, promotes the extensive discussions of electrical explosion process in high energy density. This paper presents the electrical-explosion behavior of carbon fibers subjected to about 20 kA, ~5 µs high-density current pulse igniting an intense electron beam accelerator. After electrical explosion, and surface rupture, submicron particles, fibrillar and strip-shaped structures were observed, experimentally supporting the microstructure model (skin-core heterogeneity) of carbon fiber. Interestingly, the start and turn-off of the current were followed by radiation pulses with different intensities. It was found that the radiation was focused on the explosion stage which was characterized by an oscillating current. The instabilities of plasma produced during the explosion process play an important role in the microstructure changes of carbon fibers and the radiation generation.
Experimental evidence for the global acidification of surface ocean at the Cretaceous–Palaeogene boundary: the biogenic calcite-poor spherule layers
Authors: Premović Pavle I.
Published: July 2009

The massive amount of impact-generated atmospheric CO2at the Cretaceous-Palaeogene boundary (KPB) would have accumulated globally in the surface ocean, leading to acidification and CaCO3undersaturation. These chemical changes would have caused a crisis of biocalcification of calcareous plankton and enhanced dissolution of their shells; these factors together may have played a crucial role in forming the biogenic calcite-poor KPB spherule layers observed at numerous oceanic sites and marine (now on land) sites in Europe and Africa. Experimental data and observations indicate that the deposition spherule layer probably lasted only a few decades at most.
Morphologic variation in the USDA/ARS rhubarb germplasm collection
Authors: Pantoja Alberto , Kuhl Joseph C.
Published: July 2009

Rhubarb includes approximately 60 species in the genusRheum. It has been utilized for thousands of years for medicinal purposes, but only recently identified for its culinary use. In the mid 1700s, edible petioles were discovered on seedlings from rhubarb species. Hundreds of cultivars have since been identified for a wide range of uses from tarts to wine. Unfortunately, propagation by seed and irregular naming has resulted in a plethora of similarly named cultivars and multitude of phenotypes. Fifteen morphological characters were evaluated to differentiate rhubarb cultivars in the USDA, ARSRheumcollection in Palmer, Alaska. Two years of morphological data, focusing on horticultural characteristics indicated variation between the years. To improve cultivar resolution, the results suggest using 1 year's data instead of combining data from different years. The mean °Brix observed was 3.8, with a range from 2.2 to 6.1. Flesh colour and basal skin colour were poorly correlated (R2 = 0.462); overall skin colour was more red at the base than in the middle of the petiole. Rhubarb character categories, in particular petiole number and petiole base thickness, need to be modified to better anticipate the range of expected values, and thereby contribute improved reproducibility and reliability to separate cultivars based on morphological characters.
Zur klinischen Validität einer computergestützten Aufmerksamkeitstestbatterie für Kinder (KITAP) bei 7- bis 10-jährigen Kindern mit ADHS
Authors: Drechsler Renate , Rizzo Patrizia , Steinhausen Hans-Christoph
Published: July 2009

Obwohl neuropsychologische Tests zwischen Kindern mit und ohne ADHS unterscheiden, ist doch ihr Beitrag zur klinischen Diagnose oft unklar. Daher wurde untersucht, wie gut eine computergestützte Testbatterie zur Aufmerksamkeitsprüfung bei Kindern (KITAP) zwischen Kindern mit und ohne ADHS trennt und welchen Beitrag sie bei der diagnostischen Klassifikation leisten kann. In der Studie führten 50 Kinder mit ADHS und 50 gesunde Kinder im Alter von sieben bis zehn Jahren Untertests zu Alertness, Flexibilität, Inhibitionskontrolle, Daueraufmerksamkeit, geteilter Aufmerksamkeit und Ablenkbarkeit durch. Es zeigte sich, dass vier der sechs Aufgaben zwischen den Gruppen signifikant trennten. Die Kombination von zwei oder mehr beeinträchtigten Untertests erwies sich zwar als bester Prädiktor für ADHS, war aber für klinisch-diagnostische Zwecke unzureichend. Es wird die Schlussfolgerung gezogen, dass eine computergestützte Testbatterie zwar wichtige Hinweise auf das individuelle Leistungsprofil gibt, sich eine diagnostische Klassifikation von Kindern mit und ohne ADHS aber kaum auf Normabweichungen in diesem Leistungstest stützen kann.
Das ADHS-Summercamp – Entwicklung und Evaluation eines multimodalen Programms
Authors: Petermann Ulrike , Petermann Franz , Niederberger Uwe , Stephani Ulrich , Siniatchkin Michael , Gerber Wolf-Dieter
Published: July 2009

Die Studie beschäftigt sich mit der Frage, ob und inwieweit ein multimodales, massiertes, stringent lernpsychologisch orientiertes Gruppenprogramm (ADHS-Summercamp, ASCT; 12 Tage; 100 Stunden) die klinische ADHS-Kernsymptomatik günstig beeinflussen kann. Dabei sollte der besondere Einfluss von Response-Cost-Token (RCT) untersucht werden. Das ASCT wurde in einem Prä-Post1-Post2-Design mit einer standardisierten Elternberatungsgruppe (SEB) verglichen. An der Studie nahmen insgesamt 27 Kinder im Alter zwischen 6 und 17 Jahren teil, die nach Alter, Geschlecht und Kernsymptomatik per Zufall entweder der ASCT-Gruppe (N = 18) oder der SEB-Gruppe (N = 19) zugeordnet wurden. Während des Summercamps wurden neben einem sozialen Kompetenztraining schulbezogene Tests und Sport durchgeführt, wobei über alle Alltagssituationen hinweg das RCT systematisch angewendet wurde. Zudem erhielten die Kinder doppelblind, randomisiert und cross-over die drei folgenden Medikationen: Methylphenidat unretardiert, Methylphenidat retardiert und Placebo jeweils vier Tage lang. Das Verhalten der Kinder der ASCT-Gruppe wurde während des Summercamps zu festgelegten Zeitpunkten und in standardisierten Situationen durch geschulte Beobachter mithilfe von validierten Beobachtungsbögen (SKAMP; FBB-HKS) bewertet. Beide Gruppen erhielten zudem vor der Intervention, sechs Monate und zwei Jahre danach Eltern- und Lehrerbeobachtungsbögen, die sich u. a. auf die ADHS-Kernsymptomatik bezogen. Die varianzanalytische Auswertung zeigte eine signifikante Verbesserung der ADHS-Kernsymptomatik der ASCT-Gruppe, die auch nach zwei Jahren relativ stabil blieb. Dabei konnten diese Verbesserungen vorwiegend die Lehrer beobachten. Dagegen zeigte sich bei der SEB-Gruppe in der Lehrerbeobachtung eine Zunahme der Symptomatik nach der Beratung. Die Effekte der ASCT-Gruppe konnten vorwiegend auf die Wirkung des RCT zurückgeführt werden. Das Gruppentraining führt zu positiven, langfristigen klinischen Effekten, wenn es mit einem RCT verknüpft ist. Die Einführung von ADHS-Summercamps in Tageskliniken für Kinder und Jugendliche, aber auch in verhaltenstherapeutischen Ambulanzen und Praxen, bietet sich besonders aus ökonomischen Gründen an.
Der Frankfurter Imitationstest für 36 Monate alte Kinder (FIT 36)
Authors: Goertz Claudia , Kolling Thorsten , Frahsek Stefanie , Knopf Monika
Published: July 2009

Um nicht sprachliche Gedächtnisleistungen von 36 Monate alten Kindern zu erfassen, wurde ein Verfahren zur Verzögerten Imitation entwickelt. Der Frankfurter Imitationstest (FIT 36) umfasst 40 Handlungsschritte, die sich aus acht Items mit vier bis sechs Einzelschritten zusammensetzen. Im Mittel imitieren Dreijährige (N = 82) 25 Handlungsschritte. In einer unabhängigen Reliabilitätsstudie (N = 24) konnte seine Test-Retest-Reliabilität mit r = .55 nachgewiesen werden. Im Vergleich mit den Gedächtnisleistungen im freien Abruf von Bildern, dem „Schatzkästchen“ sowie dem Untertest „Wörter erklären“ aus dem Wiener Entwicklungstest (WET) zeigten sich teilweise Zusammenhänge zur Imitationsleistung, die Hinweise auf die Validität des Tests liefern. Während sich bei der Durchführung der verbalen Gedächtnistests sowie dem „Schatzkästchen“ (WET) teilweise mangelndes Instruktionsverständnis bzw. Motivationsprobleme zeigten, wurde der FIT 36 durch seine starke Handlungskomponente von den Kindern engagiert ausgeführt. Der FIT 36 bildet eine wichtige Ergänzung zu Gedächtnisverfahren für Dreijährige.
Dialektisch Behaviorale Therapie (DBT) und Kognitiv Behaviorale Therapie (CBT) für Jugendliche mit Anorexia und Bulimia nervosa im Vergleich
Authors: Salbach-Andrae Harriet , Bohnekamp Inga , Bierbaum Tobias , Schneider Nora , Thurn Claudia , Stiglmayr Christian , Lenz Klaus , Pfeiffer Ernst , Lehmkuhl Ulrike
Published: July 2009

Ziel der vorliegenden randomisierten kontrollierten Studie war die Überprüfung der Wirksamkeit der Kognitiv Behavioralen Therapie (CBT) sowie der Dialektisch Behavioralen Therapie (DBT-AN/BN) bei Patienten mit einer Anorexia nervosa (AN) und Bulimia nervosa (BN). 50 weibliche Patienten (12;4 – 21;0 Jahre) nahmen an der Untersuchung teil. 19 Patientinnen absolvierten eine 25-wöchige CBT, 16 eine 25-wöchige DBT-AN/BN und 15 wurden für 3 Monate einer Wartekontrollgruppe (WKG) zugeordnet. Am Ende der Behandlung erfüllten in der CBT-Gruppe noch 42.1 %, in der DBT-AN/BN-Gruppe 37.5 % und in der WKG alle Patienten die Kriterien einer Essstörung nach DSM-IV. Sowohl die CBT als auch die DBT-AN/BN führten verglichen mit der WKG zu einer Reduktion der Kalorienvermeidung, der unregelmäßigen Nahrungsaufnahme und der aktuellen psychischen Belastung sowie zu einer Erhöhung des BMI. Bezogen auf die Körperbildstörung, die Autonomieentwicklung, die Emotionsregulation sowie den Perfektionismus konnten nur geringe positive Effekte erzielt werden.
New Policy on Eos Submissions
Authors: Richman Barbara T.
Published: July 2009

Starting immediately, Eos is eliminating the requirement to submit a proposal for a feature article before submitting the full manuscript. Rather, we welcome the submission of full feature articles. This change will improve the timeliness of the manuscript review process.

In April 2007, Eos began asking authors to submit proposals before the editors invited submission of a feature article to help ensure that Eos balanced its coverage of all of AGU's disciplines (Eos, 88(11), 13 March 2007). Assessments show that the balance of subject matter has improved over the past few years, but the proposal process itself does not contribute effectively to that goal. Requiring proposals for feature articles prolonged the time between initial submission and the acceptance of an invited feature—frustrating authors and editors alike.
Rain on Snow: Little Understood Killer in the North
Authors: Putkonen Jaakko , Grenfell Thomas C. , Rennert Kevin , Bitz Cecilia , Jacobson Paul , Russell Don
Published: July 2009

In October 2003, a severe rain‐on‐snow (ROS) event killed approximately 20,000 musk‐oxen (Figure 1) on Banks Island, which is the westernmost of the Canadian Arctic islands (approximately 380 kilometers by 290 kilometers in size). The event reduced the isolated herd by 25% and significantly affected the people dependent on the herd's well‐being. Because of the sparsity of weather stations in the Arctic and the lack of routinely deployed weather equipment that was capable of accurately sensing the ROS event, its detection largely was based on reports from hunters who were in the affected areas at the time.

Such events can significantly alter a frozen ecosystem—with changes that often persist for the remainder of a winter—by creating ice layers at the surface of, within, or below the snowpack. The water and ice layers are known to facilitate the growth of toxic fungi, significantly warm the soil surface under thick snowpack, and deter large grazing mammals. Although ROS events of the magnitude that was experienced in Banks Island in 2003 likely have reverberations throughout the entire Arctic and subarctic ecosystem, little is presently known about them and their impacts. As understanding of ROS events expands, many ROS‐related aspects of the Arctic ecology and hydrology are likely to be discovered. They may include topics such as the fate of small mammals under the snowpack at the iced soil surface, the difficulty of ptarmigans to burrow into the iced snow, the limited infiltration of spring snowmelt into the iced over soil, and the changing drifting patterns of ice‐crusted snowpack.
Magnetosonic Mach number dependence of the efficiency of reconnection between planetary and interplanetary magnetic fields
Authors: Grocott A. , Badman S. V. , Cowley S. W. H. , Milan S. E. , Nichols J. D. , Yeoman T. K.
Published: July 2009

We present a statistical investigation into the magnetosonic Mach number dependence of the efficiency of reconnection at the Earth's dayside magnetopause. We use the transpolar voltage VPC, derived from radar observations of the ionospheric electric field, as a proxy for the dayside reconnection voltage. Our results show that the IMF clock angle dependence of VPC is closely approximated by the function f(θ) = sin2(θ/2), which we use in the derivation of a solar wind transfer function E* = ESWf(θ), wherein ESW is the solar wind electric field. We find that VPC is strongly related to E*, increasing almost linearly with small E* but saturating as E* becomes high. We also find that E* is strongly dependent on the magnetosonic Mach number, MMS, decreasing to near‐zero values as MMS approaches 12, due principally to decreasing values of the IMF strength. VPC, on the other hand, is only weakly related to MMS and, for lower, more usual values of E*, actually shows a modest increase with increasing MMS. This result has implications for the solar wind‐magnetosphere interaction at the outer planets where the Mach number is typically much higher than it is at 1 AU. Examples of SuperDARN convection maps from two high Mach number intervals are also presented, illustrating the existence of fairly typical reconnection driven flows. We thus find no evidence for a significant reduction in the magnetopause reconnection rate associated with high magnetosonic Mach numbers.
High‐level expression and large‐scale preparation of soluble HBx antigen from Escherichia coli
Authors: Liu Dong , Zou Liyun , Li Wanling , Wang Li , Wu Yuzhang
Published: July 2009

The HBx (hepatitis B virus X protein) is a multifunctional regulator of cellular signal transduction and transcription pathways in host‐infected cells. Evidence suggests that HBx has a critical role in the pathogenesis of hepatocellular carcinoma. However, the lack of efficient large‐scale preparation methods for soluble HBx has hindered studies on the structure and function of HBx. Here, a new pMAL‐c2x protein fusion and purification system was used for high‐level expression of soluble HBx fusion protein. The high‐purity fusion protein was obtained via amylose resin chromatography and Q‐Sepharose chromatography. The untagged HBx was efficiently and rapidly purified by Sephadex G‐75 chromatography after cleavage by Factor Xa at 23 °C. The purity of active HBx protein was >99% with a very stable secondary structure dominated by α‐helix, β‐sheet and random structure. The purified HBx protein can be analysed to determine its crystal structure and function and its capabilities as an effective immunogen.
High ambient glucose induces angiotensin-independent AT-1 receptor activation, leading to increases in proliferation and extracellular matrix accumulation in MES-13 mesangial cells
Authors: Yano Naohiro , Suzuki Daisuke , Endoh Masayuki , Cao Tram N. , Dahdah John R. , Tseng Andy , Stabila Joan P. , McGonnigal Bethany G. , Padbury James F. , Tseng Yi-Tang
Published: July 2009

Diabetic nephropathy is associated with mesangial ECM (extracellular matrix) accumulation. We have shown that AT-1R [Ang II (angiotensin II) type I receptor] signalling induces ECM proteins via transactivation of PI3K (phosphoinositide 3-kinase) in mesangial cells. In the present study, we examined the mechanisms underlying the effect of high ambient glucose on cell proliferation and ECM expansion in a mesangial context. High glucose induced increases in PI3K activity, proliferation and ECM accumulation in mesangial cells. These effects were abrogated by losartan, an AT-1R antagonist, but not by [Sar1,Thr8]-Ang II (Sar is sarcosine), an inactive analogue of Ang II, or by a neutralizing antibody against Ang I/II. Overexpression of a constitutively active PI3Kα or AT-1R alone was sufficient to induce similar changes by high glucose. In contrast, overexpression of an inactive AT-1R lowered the basal levels and rendered the cells non-responsive to high glucose. Moreover, cells overexpressing wild-type AT-1R had enhanced sensitivity to acute Ang II stimulation. These cells, however, did not respond to conditioned medium obtained from mesangial cells cultured in high glucose. We further demonstrated that iAng (intracellular Ang II) can be induced by high glucose but only under certain conditions. Efficient suppression of iAng by short hairpin RNA against angiotensinogen, however, did not affect high glucose-induced effects on MES-13 cells. These results suggest that high ambient glucose induces activation of AT-1R in an Ang II-independent manner to transactivate PI3K, resulting in proliferation and ECM accumulation in mesangial cells.
Inositol pyrophosphates modulate hydrogen peroxide signalling
Authors: Onnebo Sara Maria Nancy , Saiardi Adolfo
Published: July 2009

Inositol pyrophosphates are involved in a variety of cellular functions, but the specific pathways and/or downstream targets remain poorly characterized. In the present study we use Saccharomyces cerevisiae mutants to examine the potential roles of inositol pyrophosphates in responding to cell damage caused by ROS (reactive oxygen species). Yeast lacking kcs1 [the S. cerevisiae IP6K (inositol hexakisphosphate kinase)] have greatly reduced IP7 (diphosphoinositol pentakisphosphate) and IP8 (bisdiphosphoinositol tetrakisphosphate) levels, and display increased resistance to cell death caused by H2O2, consistent with a sustained activation of DNA repair mechanisms controlled by the Rad53 pathway. Other Rad53-controlled functions, such as actin polymerization, appear unaffected by inositol pyrophosphates. Yeast lacking vip1 [the S. cerevisiae PP-IP5K (also known as IP7K, IP7 kinase)] accumulate large amounts of the inositol pyrophosphate IP7, but have no detectable IP8, indicating that this enzyme represents the physiological IP7 kinase. Similar to kcs1Δ yeast, vip1Δ cells showed an increased resistance to cell death caused by H2O2, indicating that it is probably the double-pyrophosphorylated form of IP8 [(PP)2-IP4] which mediates the H2O2 response. However, these inositol pyrophosphates are not involved in directly sensing DNA damage, as kcs1Δ cells are more responsive to DNA damage caused by phleomycin. We observe in vivo a rapid decrease in cellular inositol pyrophosphate levels following exposure to H2O2, and an inhibitory effect of H2O2 on the enzymatic activity of Kcs1 in vitro. Furthermore, parallel cysteine mutagenesis studies performed on mammalian IP6K1 are suggestive that the ROS signal might be transduced by the direct modification of this evolutionarily conserved class of enzymes.
Development of Dictyostelium discoideum is associated with alteration of fucosylated N-glycan structures
Authors: Schiller Birgit , Hykollari Alba , Voglmeir Josef , Pöltl Gerald , Hummel Karin , Razzazi-Fazeli Ebrahim , Geyer Rudolf , Wilson Iain B. H.
Published: July 2009

The social amoeba Dictyostelium discoideum has become established as a simple model for the examination of cell–cell interactions, and early studies suggested that shifts in glycosylation profiles take place during its life cycle. In the present study, we have applied HPLC and mass spectrometric methods to show that the major N-glycans in axenic cultures of the AX3 strain are oligomannosidic forms, most of which carry core fucose and/or intersecting and bisecting N-acetylglucosamine residues, including the major structure with the composition Man8GlcNAc4Fuc1. The postulated α1,3-linkage of the core fucose correlates with the cross-reactivity of Dictyostelium glycoproteins with a horseradish peroxidase antiserum; a corresponding core α1,3-fucosyltransferase activity capable of modifying oligomannosidic N-glycans was detected in axenic Dictyostelium extracts. The presence of fucose on the N-glycans and the reactivity to the antiserum, but not the fucosyltransferase activity, are abolished in the fucose-deficient HL250 strain. In later stages of development, N-glycans at the mound and culmination stages show a reduction in both the size and the degree of modification by intersecting/bisecting residues compared with mid-exponential phase cultures, consistent with the hypothesis that glycosidase and glycosyltransferase expression levels are altered during the slime mould life cycle.
Light-induced increase of nonradiative recombination centers in hydrogenated nanocrystalline silicon solar cells under reverse electric bias
Authors: Wang Keda , Han Daxing , Yue Guozhen , Yan Baojie , Yang Jeffrey , Guha Subhendu
Published: July 2009

We studied photoluminescence (PL) of hydrogenated nanocrystalline silicon (nc-Si:H) solar cells in the annealed and light-soaked states under various electric biases during light soaking. PL intensity from grain boundaries decreased after light soaking under a reverse bias, which implies a reduction in the radiative recombination rate as a consequence of an increase in nonradiative recombination centers in grain-boundary regions. However, such PL change was not observed after light soaking under open-circuit condition. The results suggest that the reverse bias during light soaking enhanced metastable defect generation in the grain-boundary regions, which is consistent with the explanation in our previous nc-Si:H cell stability studies.
An Experimental Comparison of Negotiation Strategies for Siting NIMBY Facilities
Authors: Chiu Ching-Pin , Lai Shih-Kung
Published: July 2009

The quality of the urban living environment is strongly related to the provision and planning or design of public facilities, of which NIMBY, not-in-my-back-yard, facilities are often resisted by residents. Therefore, selecting the location for NIMBY facilities has become more and more difficult and time consuming. In Taiwan in particular, when the tenure landholding system is adopted, along with financial difficulties, frequent mass protests take place in relation to environmental issues, and consequently lead to financial development issues for the country. Hence, the interaction between the government and the public becomes critical and urgent. O'Hare believes that NIMBY facilities can be seen as a prisoner's dilemma game in game theory, and Camerer also points out that public issues such as environmental concerns are also a type of prisoner's dilemma game. This research adopts an alternative methodology to that of Axelrod, in which a computer simulation was used to compare interactive strategies in prisoner's dilemma games. On the basis of a deductive analysis comparing different interactive strategies in prisoner's dilemma games, in this research an experiment was conducted to verify empirically the results of that analysis in the context of siting NIMBY facilities. The experiment has once again proven that tit-for-tat is indeed a comparatively more effective strategy than the others, not only for the player under consideration, but also for the society as a whole, with the assumption of symmetric information, and it can be used as a reference when political decisions are to be made from the government regarding NIMBY facilities.