bluuebunny/crossref_metadata_2025 huggingface dataset:
Störungsrechnung für lineare gewöhnliche Differentialoperatoren Teil II
Authors: Schmidt A.
Published: May 2007

Es wird auf direktem Wege gezeigt, daß alle nach Potenzen des Störparameters ε fortschreitenden Reihen, die ein Eigenwertproblem, bestehend aus einem System linearer gestörter Differentialgleichungen und Randbedingungen, formal erfüllen, auch konvergieren und das Problem lösen.
Zur Elastizitätstheorie des dreidimensionalen, dehnsteifen Punkthaufens
Authors: Schade D.
Published: May 2007

Es wird die Elastizitätstheorie des Quader‐ und Tetraeder‐Punkthaufens vorgestellt. An Beispielen wird gezeigt, daß es Anwendungen der Theorie des Punkthaufens in der Methode der finiten Elemente gibt.
On the interpretation of structural damping
Authors: Rösel R.
Published: May 2007

The usual definition of structural damping leads naturally to a complex differential equation of motion, the interpretation of the complex solution of which has caused some confusion in the literature. Even a real equation obtained by a straightforward method does not prove to be satisfactory. For this reason, a new principle is introduced, that of “accompanying”, virtual motion; the resulting equation and solution are still such as one would expect, but the interpretation becomes physically straightforward and mathematically coherent. This is shown first (for single degree of freedom) for the homogeneous equation, to illustrate a case of non‐periodic motion; then, also introducing an “accompanying”, virtual force, the inhomogeneous equation is solved. Finally, the generalization to several degrees of freedom is indicated, and the implications of the method are illustrated by the typical case of aerodynamic flutter.
Convergence of Huber's method for heat conduction problems with change of phase
Authors: Fasano A. , Primicerio M.
Published: May 2007

In diesem Artikel wird die Konvergenz einer Methode zur Lösung einer Wärmeleitungsaufgabe mit Phasenübergang bewiesen. Die Methode scheint einige bedeutungsvolle numerische Vorteile zu bieten. Es wird eine α‐priori Fehlerabschätzung gegeben.
The Turbulent EMF u′ × B′ in the Case of Non‐Vanishing Mean Flow
Authors: Krause F.
Published: May 2007

A more convenient formula (c. f. [2]) for the turbulent mean electromotive force u' × B' in the presence of a nonvanishing mean flow is derived by slightly modifying the representation ([2], [3]) of the Green's tensor Gij of the induction equation for velocity fields with constant rate of strain. Furthermore the existence of growing dynamo solutions of the induction equation of the mean field is analysed under the assumption that there is a linear relation with constant coefficients connecting the turbulent emf and the mean magnetic field.
The Axisymmetric Boussinesq Problem for a Radiating Heated Punch
Authors: Chakrabarti S.
Published: May 2007

The solution of the axisymmetric heated punch problem when the heat flow is prescribed on a finite part of the boundary, the remainder radiating in accordance with Newton's law is obtained. The temperature, displacement and stresses have been evaluated. The results show appreciable differences with the cases when radiation is neglected.
Long Time Behavior of a Decaying Vortex
Authors: Gunzburger M. D.
Published: May 2007

The motion and decay of a vortex submerged in a two‐dimensional inviscid stream is considered with view of seeking solutions valid for all time. A multiple time scale perturbation scheme is used to obtain solutions. The important effects of viscosity near the center of the vortex are included by a systematic procedure. To illustrate the theory solutions are then presented for the motion of a vortex subject to a sudden uniform gust and for the motion of a vortex in the presence of a wall.
Ein neues Variationsprinzip mit Anwendung auf Schwingungen flacher Schalen nach der Methode der finiten Elemente
Authors: Tabarrok B. , Gass N.
Published: May 2007

Ein finites Element für die Schwingungsanalyse flacher Schalen wurde formuliert. Die Entwicklung der Elementgleichungen basiert auf einem zweifeldrigen Variationsprinzip. Innerhalb des Elementes wird ein Impulsfeld angenommen, am Rand ein Geschwindigkeitsfeld. Die Extremalbedingungen des Funktionals sichern a) die Befriedigung der Kompatibilität innerhalb des Elementes, b) die Anpassung des hergeleiteten Geschwindigkeitsfeldes innerhalb des Elementes mit dem angenommenen Feld am Rand und c) die Gleichgewichtsbedingungen entlang der Ränder der Elemente. Die wichtigsten Elementmatrizen sind in expliziter Form angegeben. Verschiedene Beispiele wurden analysiert und dabei die Wirkungsweise des Verfahrens aufgezeigt.
Asymptotische Näherungen der modifizierten Mathieuschen Funktionen für komplexe Eigenwertparameter h = |h| (1 ±; j)/√2
Authors: Rembold B.
Published: May 2007

Zur Berechnung der Übertragungseigenschaften von verlustbehafteten Leitungen mit elliptischem Querschnitt werden in Weiterführung einer Arbeit von Piefke asymptotische Näherungen der modifizierten Mathieuschen Funktionen für große komplexe Eigenwertparameter h = |h| (1 ± j)/√2 hergeleitet. Die Ergebnisse werden in einigen Bildern mit den exakten Funktionen verglichen.
Lineare elliptische Zustände mit nichtlinearem Zielfunktional
Authors: Miersemann E.
Published: May 2007

Wir untersuchen elliptische Zustände, die durch das Dirichletproblem gegeben sind. Das Zielfunktional ist ein allgemeiner nichtlinearer Ausdruck. Wir zeigen die Existenz der optimalen Steuerung. Für eine spezielle beschränkte Steuerungsmenge beweisen wir die Regularität der optimalen Steuerung.
Geometrically Nonlinear Shell Theory in the Light of the Method of Asymptotic Integration
Authors: Novotný B.
Published: May 2007

Die in der Arbeit beschriebene Methode der asymptotischen Integration gestattet ein iteratives Vorgehen zur sukzessiven Bestimmung einer Näherungslösung der dreidimensionalen Gleichungen der geometrisch nichtlinearen Schalentheorie. Es wird eine Klassifikation der Schalenprobleme in Ausdrücken qualitativer und quantitativer Charakteristiken der Schalendaten dargeboten und auf eine Möglichkeit hingewiesen, den Einfluß verschiedener Typen von äußeren Einwirkungen abzuschätzen. Auf der durch die asymptotische Analysis gewonnenen Grundlage kann eine allgemeine Information über das Verhalten der Schale abgeleitet werden. Für gewisse Beispiele von Platten und Schalen werden die auf diesem Wege gemachten Voraussetzungen mit numerischen Ergebnissen verglichen.
Thermodynamische Analyse von Deformationsgesetzen des Modellstruktursystems
Authors: Balke Herbert
Published: May 2007

Es werden die Eigenschaften der Verzerrungsarbeit untersucht, die mit Hilfe nichtlinear‐rheonomer Deformationsgesetze berechnet wurde. Durch Einführung einer wegabhängigen Viskosität wird gezeigt, daß die verwendeten Deformationsgesetze thermodynamisch zulässig sind.
Der Einfluß der Machzahl auf wellenwiderstandsoptimierte Rümpfe und Profile bei Überschallanströmung
Authors: Wellmann J.
Published: May 2007

Die nach der Theorie schlanker Körper berechneten Konturen mit minimalem Wellenwiderstand zeigen keine Abhängigkeit von der Machzahl, wohingegen einige nichtlineare Optimierungen einen derartigen Einfluß aufweisen. Ausgehend von einer widerspruchsfreien Linearisierung der Erhaltungssätze wird eine geschlossene lineare Theorie angegeben, in der die Optimierung von Rotationskörpern exakt und explizit möglich ist. Die durch die Stromfunktion dargestellten Konturen enthalten die alten Lösungen als asymptotische Sonderfälle und sind auch für höhere Machzahlen gültig.
Investigation of Microwave Absorption of Surface-State Electrons on Liquid 3He
Authors: Konstantinov Denis , Isshiki Hanako , Akimoto Hikota , Shirahama Keiya , Kono Kimitoshi
Published: May 2007

We report on the experimental study of the resonance microwave absorption of surface-state electrons (SSE) on liquid 3He. The absorption is detected as a variation of the microwave power passing through the experimental cell, or as a resonance-induced change in the electron conductivity. In the latter method a decrease of the conductivity is observed, which points out on the possibility of substantial heating of the electrons by the absorbed microwave power. In a vapor-atom scattering regime the temperature dependence of the linewidth agrees well with the theoretical model, and the absolute value of the measured linewidth is about twice larger than the theoretical one. At very high microwave power the side band absorption peaks are observed.
Results after surgical treatment of thumb duplication: A retrospective review of 33 thumbs
Authors: Maillet Marie , Fron Damien , Martinot-Duquennoy Véronique , Herbaux Bernard
Published: May 2007

Purpose

Purpose This study reports the results of surgical treatment of thumb duplication in the Clinique d'Orthopédie et de Chirurgie de l'Enfant de l'Hôpital Jeanne de Flandre in Lille (France). Methods Thirty patients (33 thumbs) operated on between 1995 and 2003 are clinically reviewed. Results The mean postoperative follow-up was 3 years and 11 months. According to Wassel's classification, the series included 12 type II duplications, two type III, 14 type IV, two type V, one type VI and two type VII. The surgical approaches consisted of simple resection of the most hypoplastic thumb (16 thumbs), the Bilhaut–Cloquet procedure (ten thumbs) and resection associated with reconstructive surgery (seven thumbs). The Bilhaut–Cloquet procedure was used in three cases for treatment of type IV duplication On the basis of the Tada scoring system, we obtained 24 good results, eight fair results and one poor result. Conclusion Based on our results, we recommend that the Bilhaut–Cloquet procedure be used not only for the treatment of type II duplication when the thumbs are both hypoplastic and symmetric but also for type IV duplication with the same clinical parameters. For the other types of duplications, we consider that resection of the most hypoplastic thumb associated with reconstructive surgery is the best surgical approach. For type VII duplication, ablation of the triphalangeal thumb remains the best option. We do not recommend osteotomy at the first surgery.
Network analysis of protein dynamics
Authors: Böde Csaba , Kovács István A. , Szalay Máté S. , Palotai Robin , Korcsmáros Tamás , Csermely Péter
Published: May 2007

The network paradigm is increasingly used to describe the topology and dynamics of complex systems. Here, we review the results of the topological analysis of protein structures as molecular networks describing their small‐world character, and the role of hubs and central network elements in governing enzyme activity, allosteric regulation, protein motor function, signal transduction and protein stability. We summarize available data how central network elements are enriched in active centers and ligand binding sites directing the dynamics of the entire protein. We assess the feasibility of conformational and energy networks to simplify the vast complexity of rugged energy landscapes and to predict protein folding and dynamics. Finally, we suggest that modular analysis, novel centrality measures, hierarchical representation of networks and the analysis of network dynamics will soon lead to an expansion of this field.
SREBP‐1c mediates the retinoid‐dependent increase in fatty acid synthase promoter activity in HepG2
Authors: Roder Karim , Zhang Lei , Schweizer Michael
Published: May 2007

Treatment of HepG2 with all‐trans retinoic acid (RA) induces expression of fatty acid synthase (FAS) mRNA and protein. Transfections show that the FAS promoter positively responds to retinoid X receptor (RXR) but not to RA receptor (RAR) agonists. Since RXR alone is capable of mediating the RA response of FAS, the existence of a classical RA‐responsive element in the FAS promoter may be ruled out. Binding sites for NF‐Y and SREBP‐1 proved to be essential for the RA response. Exposure to all‐trans RA increased mRNA and protein levels of SREBP‐1, a transcriptional activator for FAS. Overexpression of a dominant‐negative form of SREBP‐1c diminished the RA‐dependent increase in promoter activity. These data demonstrate that RXR ligands can stimulate the expression of a lipogenic gene solely by inducing transcription and cleavage of membrane‐bound SREBP‐1c.
Equine lysozyme: The molecular basis of folding, self‐assembly and innate amyloid toxicity
Authors: Morozova-Roche Ludmilla A.
Published: May 2007

Calcium‐binding equine lysozyme (EL) combines the structural and folding properties of c‐type lysozymes and α‐lactalbumins, connecting these two most studied subfamilies. The structural insight into its native and partially folded states is particularly illuminating in revealing the general principles of protein folding, amyloid formation and its inhibition. Among lysozymes EL forms one of the most stable molten globules and shows the most uncooperative refolding kinetics. Its partially‐folded states serve as precursors for calcium‐dependent self‐assembly into ring‐shaped and linear amyloids. The innate amyloid cytotoxicity of the ubiquitous lysozyme highlights the universality of this phenomenon and necessitates stringent measures for its prevention.
In vitro RNA editing in plant mitochondria does not require added energy
Authors: Takenaka Mizuki , Verbitskiy Daniil , van der Merwe Johannes A. , Zehrmann Anja , Plessmann Uwe , Urlaub Henning , Brennicke Axel
Published: May 2007

RNA editing in flowering plant mitochondria is investigated by in vitro assays. These cauliflower mitochondrial lysates require added NTP or dNTP. We have now resolved the reason for this requirement to be the inhibition of the RNA binding activity of the glutamate dehydrogenases (GDH). Both GDH1 and GDH2 were identified in RNA–protein cross‐links. The inhibition of in vitro RNA editing by GDH is confirmed by the ability of the GDH‐specific herbicide phosphinothricin to substitute for NTP. NADH and NADPH, but not NAD or NADP, can also replace NTP, suggesting that the NAD(P)H‐binding‐pocket configuration of the GDH contacts the RNA. RNA editing in plant mitochondria is thus intrinsically independent of added energy in the form of NTP.
Legionella pneumophila adaptation to intracellular life and the host response: Clues from genomics and transcriptomics
Authors: Jules Matthieu , Buchrieser Carmen
Published: May 2007

Legionella pneumophila is the causative agent of the pneumonia‐like Legionnaires’ disease. The bacterium's survival and spread depend on the ability to replicate inside eukaryotic phagocytic cells. A particular feature of Legionella is its dual host system allowing the intracellular growth in protozoa like Acanthamoeba castellanii, and during infection in human alveolar macrophages. Genome analysis and comparisons as well as expression profiling of the pathogen and the host helped to identify regulatory circuits mediating adaptation of the L. pneumophila transcriptome to the intracellular environment and gave clues for the metabolic needs of intracellular Legionella. This review will summarize what is currently known about intracellular gene expression of L. pneumophila, the transcriptional host response of the model host Dictyostelium discoideum and will present hypotheses drawn from these data with respect to subversion of host cell functions and virulence of L. pneumophila.
Computational study of bindings of olive leaf extract (OLE) to HIV‐1 fusion protein gp41
Authors: Bao J. , Zhang D.W. , Zhang J.Z.H. , Huang P. Lee , Huang P. Lin , Lee-Huang S.
Published: May 2007

Recent experimental study found that OLE (olive leaf extract) has anti‐HIV activity by blocking the HIV virus entry to host cells [Lee‐Huang, S., Zhang, L., Huang, P.L., Chang, Y. and Huang, P.L. (2003) Anti‐HIV activity of olive leaf extract (OLE) and modulation of host cell gene expression by HIV‐1 infection and OLE treatment. Biochem. Biophys. Res. Commun. 307, 1029; Lee‐Huang, S., Huang, P.L., Zhang, D., Lee, J.W., Bao, J., Sun, Y., Chang, Y.‐Tae, Zhang, J.Z.H. and Huang, P.L. (2007) Discovery of small‐molecule HIV‐1 fusion and integrase inhibitors oleuropein and hydroxytyrosol. Biochem. Biophys. Res. Commun. 354, 872–878, 879–884]. As part of a joint experimental and theoretical effort, we report here computational study to help identify and characterize the binding complexes of several main compounds of OLE (olive leaf extract) to HIV‐1 envelop protein gp41. A number of possible binding modes are found by docking oleuropein and its metabolites, aglycone, elenolic acid and hydroxytyrosol, onto the hydrophobic pocket on gp41. Detailed OLE‐gp41 binding interactions and free energies of binding are obtained through molecular dynamics simulation and MM‐PBSA calculation. Specific molecular interactions in our predicted OLE/gp41 complexes are identified and hydroxytyrosol is identified to be the main moiety for binding to gp41. This computational study complements the corresponding experimental investigation and helps establish a good starting point for further refinement of OLE‐based gp41 inhibitors.
The Safe Medical Devices Act of 1990: Implications for Health Care Personnel
Authors: White Linda
Published: May 2007

The Safe Medical Devices Act of 1990: Implications for Health Care Personnel Edited by Robert H. Stiefel 1991, 101 pp $60 AAMI members, $100 nonmembers paperback
Management skills for directors of nursing
Authors: DIOMEDE BARBARA
Published: May 2007

Management skills for directors of nursing T. C. Smith Journal of Nursing Administration Vol 23 (September 1993) 38–49
Intravenous conscious sedation use in endoscopy: Does monitoring of oxygen saturation influence timing of nursing interventions?
Authors: WATSON DONNA S. ,   Nursing Research Committee
Published: May 2007

Intravenous conscious sedation use in endoscopy: Does monitoring of oxygen saturation influence timing of nursing interventions? C. A. Hinzmann, P. M. Budden, J. Olson Gastroenterology Nursing Vol 15 (August 1992) 6–13
Gametogenesis of intergroup hybrids of hemiclonal frogs
Authors: RAGGHIANTI MATILDE , BUCCI STEFANIA , MARRACCI SILVIA , CASOLA CLAUDIO , MANCINO GIORGIO , HOTZ HANSJÜRG , GUEX GASTON-DENIS , PLÖTNER JÖRG , UZZELL THOMAS
Published: May 2007

European water frog hybrids Rana esculenta (R. ridibunda×R. lessonae) reproduce hemiclonally, by hybridogenesis: in the germ line they exclude the genome of one parental species and produce haploid gametes with an unrecombined genome of the other parental species. In the widespread L-E population system, both sexes of hybrids (E) coexist with R. lessonae (L). They exclude the lessonae genome and produce ridibunda gametes. In the R-E system, hybrid males coexist with R. ridibunda (R); they exclude either their ridibunda or their lessonae genome and produce sperm with a lessonae or with a ridibunda genome or a mixture of both kinds of sperm. We examined 13 male offspring, 12 of which were from crosses between L-E system and R-E system frogs. All were somatically hybrid. With one exception, they excluded the lessonae genome in the germ line and subsequently endoreduplicated the ridibunda genome. Spermatogonial metaphases contained a haploid or a diploid number of ridibunda chromosomes, identified through in situ hybridization to a satellite DNA marker, and by spermatocyte I metaphases containing a haploid number of ridibunda bivalents. The exception, an F1 hybrid between L-E system R. lessonae and R-E system R. ridibunda, was not hybridogenetic, showed no genome exclusion, and evidenced a disturbed gametogenesis resulting from the combination of two heterospecific genomes. None of the hybridogenetic hybrids showed any cell lines excluding the ridibunda genome, the pattern most frequent in hybrids of the R-E system, unique to that system, and essential for its persistence. A particular combination of R-E system lessonae and R-E system ridibunda genomes seems necessary to induce the R-E system type of hemiclonal gametogenesis.
OBESITY AND TIME PREFERENCE: THE HEALTH CONSEQUENCES OF DISCOUNTING THE FUTURE
Authors: ZHANG LEI , RASHAD INAS
Published: May 2007

Much focus has been placed on the obesity epidemic due to its high prevalence and the costs it imposes on society. Using 2004 data from the Roper Center, complemented with 2003 data from the Behavioural Risk Factor Surveillance System, this study analyses the possible effect that time preference has on health in the United States, as measured by the body mass index. After controlling for a variety of covariates and correcting for potential selectivity, some evidence of a positive association between time preference for the present and the body mass index can be found, particularly for males. Research in this area has policy implications in terms of creating incentives for those who lack self-control through the use of pre-commitment devices. Measures addressing self-control issues may be more effective in reducing the rising obesity rates across the world.
Diffuse-interface modelling of droplet impact
Authors: KHATAVKAR V. V. , ANDERSON P. D. , DUINEVELD P. C. , MEIJER H. E. H.
Published: May 2007

The impact of micron-size drops on a smooth, flat, chemically homogeneous solid surface is studied using a diffuse-interface model (DIM). The model is based on the Cahn–Hilliard theory that couples thermodynamics with hydrodynamics, and is extended to include non-90° contact angles. The (axisymmetric) equations are numerically solved using a combination of finite- and spectral-element methods. The influence of various process and material parameters such as impact velocity, droplet diameter, viscosity, surface tension and wettability on the impact behaviour of drops is investigated. Relevant dimensionless parameters are defined and, depending on the values of the Reynolds number, the Weber number and the contact angle, which for the cases considered here range from 1.3 to 130, 0.43 to 150 and 45° to 135°, respectively, the model predicts the spreading of a droplet with or without recoil or even rebound of the droplet, totally or partially, from the solid surface. The wettability significantly affects the impact behaviour and this is particularly demonstrated with an impact at Re = 130 and We = 1.5, where for θ < 60° the droplet oscillates a few times before attaining equilibrium while for θ ≥ 60° partial rebound of the droplet occurs, i.e. the droplet breaks into two unequal sized drops. The size of the part that remains in contact with the solid surface progressively decreases with increasing θ until at a value θ ≈ 120° a transition to total rebound happens. When the droplet rebounds totally, it has a top-heavy shape.
Interception of two spheres with slip surfaces in linear Stokes flow
Authors: LUO H. , POZRIKIDIS C.
Published: May 2007

The interception of two spherical particles with arbitrary size in an infinite linear ambient Stokes flow is considered. The particle surfaces allow for slip according to the Navier–Maxwell–Basset law relating the shear stress to the tangential velocity. At any instant, the flow is computed in a frame of reference with origin at the centre of one particle using a cylindrical polar coordinate system whose axis of revolution passes through the centre of the second particle. Taking advantage of the axial symmetry of the boundaries of the flow in the particle coordinates, the problem is formulated as a system of integral equations for the zeroth, first, and second Fourier coefficients of the boundary traction with respect to the meridional angle. The force and torque exerted on each particle are determined by the zeroth and first Fourier coefficients, while the stresslet is determined by the zeroth, first, and second Fourier coefficients. The derived integral equations are solved with high accuracy using a boundary element method featuring adaptive element distribution and automatic time step adjustment according to the inter-particle gap. The results strongly suggest the existence of a critical value for the slip coefficient below which the surfaces of two particle collide after a finite interception time. The critical value depends on the relative initial particle positions. The particle stress tensor and coefficients of the linear and quadratic terms in the expansion of the effective viscosity of a dilute suspension in terms of the concentration in simple shear flow are discussed and evaluated. Surface slip significantly reduces the values of both coefficients and the longitudinal particle self-diffusivity.
On the extraction of gas from multilayered rock
Authors: FARCAS ADRIAN , WOODS ANDREW W.
Published: May 2007

This paper presents some simple analytical and numerical models which describe the dynamics of gas flowing from a multilayered low-permeability porous rock into a fracture. The models account for the vertical flow between relatively high- and low-permeability layers. The motion of gas in a permeable rock is governed by a nonlinear diffusion equation for the gas pressure. We analyse the gas flow described by this equation in both bounded and unbounded domains. In both cases simple scalings laws are developed to determine the fluxes and the dimensions of the regions within the rock which may be depleted over a given time scale. These are compared with the results of a full numerical model.
Role of the tip vortex in the force generation of low-aspect-ratio normal flat plates
Authors: RINGUETTE MATTHEW J. , MILANO MICHELE , GHARIB MORTEZA
Published: May 2007

We investigate experimentally the force generated by the unsteady vortex formation of low-aspect-ratio normal flat plates with one end free. The objective of this study is to determine the role of the free end, or tip, vortex. Understanding this simple case provides insight into flapping-wing propulsion, which involves the unsteady motion of low-aspect-ratio appendages. As a simple model of a propulsive half-stroke, we consider a rectangular normal flat plate undergoing a translating start-up motion in a towing tank. Digital particle image velocimetry is used to measure multiple perpendicular sections of the flow velocity and vorticity, in order to correlate vortex circulation with the measured plate force. The three-dimensional wake structure is captured using flow visualization. We show that the tip vortex produces a significant maximum in the plate force. Suppressing its formation results in a force minimum. Comparing plates of aspect ratio six and two, the flow is similar in terms of absolute distance from the tip, but evolves faster for aspect ratio two. The plate drag coefficient increases with decreasing aspect ratio.
A conditional stability criterion based on generalized energies
Authors: NERLI A. , CAMARRI S. , SALVETTI M. V.
Published: May 2007

An energy criterion for conditional stability is proposed, based on the definition of generalized energies, obtained through a perturbation of the classical L2 (kinetic) energy. This perturbation is such that the contribution of the linear term in the perturbation equation to the generalized energy time derivative is negative definite. A critical amplitude threshold is then obtained by imposing the monotonic decay of the generalized energy. The capabilities of the procedure are appraised through the application to three different low-dimensional models. The effects of different choices in the construction of the generalized energy on the prediction of the critical amplitude threshold in the subcritical regime are also discussed.
Impact of different pH thresholds for 24-hour dual probe pH monitoring in patients with suspected laryngopharyngeal reflux
Authors: Reichel O , Issing W J
Published: May 2007

Objectives:

The gold standard test for laryngopharyngeal reflux is 24-hour pH monitoring, which determines the reflux area index with a pH threshold of less than four (i.e. the reflux area index four). However, refluxed pepsin is able to cause laryngeal injury at pH levels above five.

Study design:

Prospective study.

Materials and methods:

In order to establish normative values for a reflux area index with a pH threshold of less than five (i.e. the reflux area index five), 29 healthy volunteers underwent pH monitoring. In 45 patients with suspected laryngopharyngeal reflux, reflux area index four and reflux area index five were determined by pH study.

Results:

In healthy volunteers, the reflux area index five was 72.6 (95th percentile). In 29 of 44 patients, laryngopharyngeal reflux was diagnosed due to a reflux area index four of greater than 6.3. However, the reflux area index five revealed laryngopharyngeal reflux in six more patients.

Conclusions:

For exact analysis of pH monitoring results, two pH thresholds (less than four and less than five) must be considered. Further studies with a larger number of healthy volunteers are necessary in order to reveal normative values for the reflux area index five parameter.
Kernel theorems in spaces of tempered generalized functions
Authors: DELCROIX ANTOINE
Published: May 2007

In analogy to the classical isomorphism between $\mathcal{Lgrave;}(\mathcal{S}(\mathbb{R}^{n}),\mathcal{S}^{\prime}(\mathbb{R}^{m})) $ and $\mathcal{S}^{\prime}(\mathbb{R}^{n+m}) $, we show that a large class of moderate linear mappings acting between the space $\mathcal{G}_{\mathcal{S}}(\mathbb{R}^{n}) $ of Colombeau rapidly decreasing generalized functions and the space $\mathcal{G}_{\tau}(\mathbb{R}^{n}) $ of temperate ones admits generalized integral representations, with kernels belonging to $\mathcal{G}_{\tau}(\mathbb{R}^{n+m}) $. Furthermore, this result contains the classical one.
Fefferman-type metrics and the projective geometry of sprays in two
dimensions
Authors: CRAMPIN M. , SAUNDERS D. J.
Published: May 2007

A spray is a second-order differential equation field on the slit tangent bundle
of a differentiable manifold, which is homogeneous of degree 1 in the fibre
coordinates in an appropriate sense; two sprays which are projectively
equivalent have the same base-integral curves up to reparametrization. We show
how, when the base manifold is two-dimensional, to construct from any projective
equivalence class of sprays a conformal class of metrics on a four-dimensional
manifold, of signature (2, 2); the Weyl conformal curvature of these metrics is
simply related to the projective curvature of the sprays, and the geodesics of
the sprays determine null geodesics of the metrics. The metrics in question have
previously been obtained by Nurowski and Sparling (Classical and Quantum Gravity20 (2003) 4995–5016), by a different
method involving the exploitation of a close analogy between the Cartan geometry
of second-order ordinary differential equations and of three-dimensional
Cauchy–Riemann structures. From this perspective the derived metrics
are seen to be analoguous to those defined by Fefferman in the CR theory, and
are therefore said to be of Fefferman type. Our version of the construction
reveals that the Fefferman-type metrics are derivable from the scalar triple
product, both directly in the flat case (which we discuss in some detail) and by
a simple extension in general. There is accordingly in our formulation a very
simple expression for a representative metric of the class in suitable
coordinates.
Antarctic macro-zoobenthic communities: a review and an ecological classification
Authors: Gutt Julian
Published: May 2007

A partly new classification of shelf inhabiting Antarctic macro-zoobenthic communities is proposed in this review. The main components are two core communities. One is dominated by sessile suspension feeders supported by food entrained in strong near-bottom currents. Variants of this community include assemblages without sponges, those that prefer sponge spicule mats as substratum and predator-driven systems. The second core community is dominated by the infauna and mobile epifauna and controlled by vertical phytodetritus flux and soft sediments. This community is obviously restricted to areas with low current velocity, particularly in areas that are sheltered due to a heterogeneous coastal and sea floor topography. In addition, in physically controlled shallow water a small number of representatives of all these ecological guilds can become very abundant. Between both core communities a broad range of mixed assemblages exists that can be explained by a gradient in environmental conditions and trophic amensalism. A concept is also proposed for the ecological functioning of systems with extremely low abundances within ecological guilds, such as those that occur under and close to ice shelves, which cannot satisfactorily be explained by trophic limitation. These extremely low abundances may result from a shift during ontogenesis from a state with predominantly mismatched environmental conditions and ecological demands of young recruits, to a state where a match occurs.
Antarctic marine biology – two centuries of research
Authors: Hempel Gotthilf
Published: May 2007

Whilst interest in the economic exploitation of the Southern Ocean resources dates back to the last part of the 18th century scientific research into elements of the marine ecosystem only began in the mid 19th century. As far as plankton and benthos are concerned the great exploratory voyages and expeditions laid a firm taxonomic foundation on which later work was built. The most outstanding expedition contribution was from the Discovery Investigations. Concern about uncontrolled exploitation stimulated the SCAR BIOMASS programme which in turn led to CCAMLR with its modelling programmes and top predator monitoring. Recent research on pack ice communities has been aided by dedicated ice-capable research vessels whilst unmanned photographic techniques as well as SCUBA diving and experimental research facilities in the Antarctic have encouraged major research on benthos. International collaboration, interdisciplinary research and good ideas suggest Antarctic marine biology has a bright future.
Learning about Antarctic krill from the fishery
Authors: Kawaguchi So , Nicol Stephen
Published: May 2007

Antarctic krill has been studied for many decades, but we are still long way from understanding their biology to be able to make reliable predictions about the reaction of their populations to environmental change. This is partly due to certain difficulties in relation to logistics, operations and survey design associated with scientific surveys that have been obstacles for us to better understand krill biology. The krill fishery is the largest fishery in the Southern Ocean, continuously operating since early 1970s. Recent studies revealed its potential to be used as a unique source for scientific discussions to understand krill biology. In this paper, after a brief overview of krill fishery operation and krill biology, we examine how current data collection through the fishery operation could contribute to a greater understanding of krill biology, and then suggest future priorities for fisheries-related research in relation to recent changes in the Southern Ocean environment.
First evidence for a bipolar distribution of dominant freshwater lake bacterioplankton
Authors: Pearce David A. , Cockell Charles S. , Lindström Eva S. , Tranvik Lars J.
Published: May 2007

As a result of the recent application of DNA based technology to the investigation of maritime Antarctic freshwater lakes, patterns have begun to emerge in the bacterioplankton communities that dominate these systems. In this study, the bacterioplankton communities of five Antarctic and five Arctic freshwater lakes were assessed and compared with existing data in the literature, to determine whether emerging patterns in Antarctic lakes also applied to Arctic systems. Such a bipolar comparison is particularly timely, given the current interest in biogeography, the global distribution of microorganisms and the controversy over the global ubiquity hypothesis. In addition, it has recently been discovered that commonly encountered bacterial sequences, often originating from uncultivated bacteria obtained on different continents, form coherent phylogenetic freshwater clusters. In this study we encountered both identical sequences and sequences with a high degree of similarity among the bacterioplankton in lake water from both poles. In addition, Arctic freshwater lakes appeared to be dominated by some of the same groups of bacterioplankton thought to be dominant in Antarctic lakes, the vast majority of which represented uncultivated groups.
Monitoring and management in the Antarctic – making the link between science and policy
Authors: Reid Keith
Published: May 2007

Management of human impacts in the Antarctic requires an effective system of monitoring to provide information about the process being managed and the effectiveness of management actions. Human impacts arise as a result of processes that originate in the region (endogenous) and those that originate outside the region (exogenous). A number of monitoring programmes have been established in both terrestrial and marine systems to measure impacts that arise as a result of endogenous process such as fishing, tourism and research. However, most of this monitoring is surveillance monitoring, which is not linked to a specific management objective, and does not produce quantitative metrics that can be assessed and compared to agreed targets. However, defining such target levels for the Antarctic, where the aim is to minimise human impacts, is a complex process. Although potential analogues for target setting exist in other parts of the world these are generally insufficiently precautionary to be applied in the Antarctic. The challenge for scientists and policymakers working in the Antarctic is to provide quantitative measures, with agreed trigger levels, and to develop appropriate monitoring schemes to manage human impacts in the future.
Ecological responses of Antarctic krill to environmental variability: can we predict the future?
Authors: Quetin Langdon B. , Ross Robin M. , Fritsen Christian H. , Vernet Maria
Published: May 2007

Antarctic krill are a key species in the Southern Ocean ecosystem, and their life cycle appears to be correlated with, and by implication dependent upon, seasonal sea ice dynamics. Moving from correlations with environmental parameters to an understanding of the mechanisms that lead to these correlations may allow predictions of the consequences of climate change on the distribution of favourable habitat for Antarctic krill. During winter cruises in 2001 and 2002 in the region west of the Antarctic Peninsula, one of the most rapidly warming regions on the planet, ice camps were established for periods of 3–9 days. Timing of sea ice advance, chlorophyll a concentrations in ice cores, and growth rates and pigment content of larval krill all differed significantly between winters. Growth rates and pigment content of larval krill from the same ice floe were correlated, suggesting that growth rates in winter are a function of the biomass of the sea ice microbial community. Apossible mechanism underlying the correlation between recruitment success and timing of ice advance is proposed. In conjunction with other postulated habitat requirements, this proposed mechanism allows for speculation about future changes in the geographic location of favourable habitat for Antarctic krill.
Parent-Child Relationships and the Verbal Information Pathway to Fear in Children: Two Preliminary Experiments
Authors: Field Andy P. , Ball Jess E. , Kawycz Nicola J. , Moore Harriett
Published: May 2007

Parenting styles and the parent-child bond are associated with anxiety in children. Despite this association, little is known about the mechanism through which parenting has its effect. One possibility is that parenting interacts with other known pathways to fear. Two experiments are reported that look at the interaction between parenting styles and parent-child relationships and the verbal information pathway to fear. In Experiment 1, a punitive maternal parenting style was found to interact with the effect of threat information about a novel animal in 6–9-year-old children. Maternal warmth, neglect, overprotection and accurate monitoring were not found to have a significant effect. Experiment 2 showed that children reporting a greater number of negative interactions with their fathers had greater increases in fear beliefs about novel animals after both threat and no information. The quality of mother-child relationships did not significantly interact with the verbal information pathway. These experiments offer preliminary evidence that parenting practices influence how children react to negative information, which offers some insight into the potential causes of the association between parenting and anxiety in children.
Iron supplementation compliance among pregnant women in Bicol,
Philippines
Authors: Lutsey Pamela L , Dawe David , Villate Ellen , Valencia Shiela , Lopez Ofelia
Published: May 2007

Objective

To quantify factors influencing iron supplementation compliance and
haemoglobin (Hb) concentrations among pregnant women participating in an
iron supplementation programme under routine field conditions.

Design

Cross-sectional interviews and Hb measurements.

Settings

Albay and Sorsogon provinces, Bicol, Philippines.

Subjects

Three hundred and forty-six pregnant women receiving iron supplements via the
Philippine iron supplementation programme.

Results

Women had a mean Hb concentration of 10.75 ± 1.43 g
dl−1, and 56.4% were anaemic (Hb < 11.0
g dl−1). On average, the first prenatal visit occurred
at nearly 4 months (3.80 ± 1.56). The ratio of visits to number
of months pregnant was 0.51 ± 0.24. Self-reported consumption of
pills received was 85% (0.85 ± 0.23), although pill counts
suggested that consumption was 70% (0.70 ± 0.35). Using multiple
regression, an earlier first prenatal visit and greater self-reported
compliance were positively associated with Hb concentrations. Additionally,
perceived health benefits from taking the supplements and higher health
programme knowledge were positively associated with pill consumption, while
experiencing side-effects and disliking the taste of the supplements were
associated with lower pill consumption. A greater number of living children
was negatively associated with the frequency of prenatal visits. The number
of children was also directly negatively associated with Hb
concentrations.

Conclusions

Compliance was positively related to Hb concentrations. Several factors
associated with greater compliance were identified, including marital
status, number of children, health programme knowledge, side-effects,
perceived health benefits, and dislike of taste. Some of these factors may
serve as avenues for interventions to increase compliance, and ultimately Hb
concentrations.
Development of a resource for parents with advanced cancer: What do
parents want?
Authors: TURNER JANE , CLAVARINO ALEXANDRA , YATES PATSY , HARGRAVES MARYANNE , CONNORS VERONICA , HAUSMANN SUE
Published: May 2007

Objective: Parents coping with a diagnosis of advanced cancer
experience distress and guilt about the impact of the disease on their
children but report that there are few resources specific to advanced
disease to guide and support them in discussions with their children.
Although some resources have been developed to assist parents with
advanced cancer, it appears that these are not widely disseminated.

Methods: To determine the need for a brief resource that
could be given to parents at the point of diagnosis of advanced cancer,
including its content, in-depth interviews were conducted with eight women
with advanced breast cancer.

Results: Women confirmed that they had received minimal
assistance from health professionals in discussing the diagnosis with
their children, and even when professional counselors were accessed they
were not always attuned to the specific needs of parents with advanced
cancer. Women felt frustrated that information they did access focused on
early disease and lacked the details women felt they needed in coping with
advanced cancer. Women felt that there was a need for a brief resource
that reassured parents about the impact of the cancer on their children,
including practical strategies to help them cope and examples of the ways
other parents had responded to difficult questions such as about parental
death. A draft resource was developed, critically reviewed by the
participants, and their comments incorporated into a final version.

Significance of results: This article expands on the themes
highlighted by women as important to assist parents with advanced cancer,
including the final resource that was developed.
Warp & Woof
Authors: Neimeyer Robert
Published: May 2007

Warp & Woof.
HWS-Distorsionstrauma (sog. Schleudertrauma) – Ein Update
Authors: Gautschi  , Frey  , Cadosch  , Zellweger
Published: May 2007

Das Halswirbelsäulen-Distorsionstrauma ist von grosser klinischer, sozioökonomischer und versicherungstechnischer Bedeutung. Eine Vielzahl von Problemen im Hinblick auf Diagnostik, Klassifikation, Therapie und Begutachtung sind bis heute nur unzureichend gelöst. Die Diagnose ist zum grössten Teil subjektiv und die ideale Behandlung wird immer wieder kontrovers diskutiert. Glücklicherweise haben Fortschritte in der Medizin zur Entwicklung eines prognostischen Klassifizierungssystems, objektiven Diagnosetests, verschiedenen Behandlungsmodalitäten und, am Wichtigsten, zur Entwicklung von sichereren Fahrzeugen geführt. Aktuelle wissenschaftliche Erkenntnisse zur Behandlung und Therapie sind bisher aber nur ungenügend in den klinischen Alltag integriert worden, dies obwohl moderne Therapiestrategien mit medikamentöser Therapie zusammen mit frühzeitiger Physiotherapie gute Ergebnisse zeigen. Klare Diagnosekriterien und Behandlungsrichtlinien würden dem vor allem in der Deutschschweiz beklagten massiven Kostenanstieg durch HWS-Distorsionstraumata entgegenwirken.
Three‐dimensional self‐potential inversion for subsurface DNAPL contaminant detection at the Savannah River Site, South Carolina
Authors: Minsley Burke J. , Sogade John , Morgan F. Dale
Published: May 2007

Self‐potential (SP) data are collected over an area of approximately 250 m2 at the Department of Energy Savannah River Site where there is known subsurface dense nonaqueous phase liquid (DNAPL) contamination. Nonpolarizing electrodes are used to measure the SP signal on a two‐dimensional (2‐D) surface grid with 2‐m spacing in both horizontal directions, and four borehole arrays with 3.7‐m electrode spacing and 25.6‐m total depth. The primary contaminants, tetrachloroethylene (PCE) and trichloroethylene (TCE), are known to undergo redox reactions in the environment. Variations in the subsurface redox conditions are proposed as an electrochemical source for the SP signals measured in this investigation. A 3‐D self‐potential inversion algorithm is used to find an electrical current source model, taking into account the resistivity structure derived from a 3‐D spectral induced polarization survey at the same field location. The sources and sinks of electrical current can be related to the zones of relative high or low redox potential and are therefore interpreted in the context of contaminated areas. These results are reasonably correlated with DNAPL concentration data obtained from several ground‐truth well measurements, indicating that the SP sources can be an indicator of contaminated areas where electrochemical source mechanisms are active. In several cases, however, the SP sources and contaminant concentrations are not correlated, reflecting the spatial variability of biogeochemical parameters in the Earth that control the SP response in addition to concentration. More extensive geochemical ground‐truth information is therefore needed to validate the self‐potential source inversion methodology and develop it as a predictive tool in the context of contaminated sites.