bluuebunny/crossref_metadata_2025 huggingface dataset:
Leben allein aus Gnade. Eph 2.1-10 und die paulinische Rechtfertigungsbotschaft
Authors: Gerber Christine
Published: June 2011

In view of some ‘Pauline’ sounding phrases, Eph 2.8-9 is held to be one of the most adequate receptions of the theologoumenon of justification by faith, not works. So could the text be an indicator in the discussion about the right ‘Perspective on Paul’? This paper argues instead that we should read Eph 2.8-9 in its own context and that means first of all that we should follow the flow of the dominant metaphor of ‘dead and alive’. While some phrases might be a Pauline reminiscence, the text as a whole deals with the grace of God in order to substantiate the demand for a life lived according to God's will, as described in greater detail in Ephesians 4–6. Nevertheless Eph 2.1-10 is broadly coherent with Paul's theology.
Why Did the Early Christians Call Themselves ἡ ἐκκλησία?
Authors: Trebilco Paul
Published: June 2011

It is argued that ἐκκλησία was first used by the Hellenists, probably in Jerusalem, and that it was chosen because of its strong background in thelxx. This raises the issue of why ἐκκλησία was chosen rather than συναγωγή, which occurs over twice as often in thelxx. The case is put that ἐκκλησία was chosen because συναγωγή was already in use by Jewish communities as a designation for their groups and their buildings. This view has not been argued for in detail, and the implications of this choice have not been fully explored. Through the use of ἐκκλησία the Hellenists could express their continuity with the OT ‘assembly’ of the people of God and could also distinguish themselves from other Jewish communities, without making the claim that they alone were the heirs of that people.
The Encomiastic Topics of Syncrisis as the Key to the Structure and Argument of Hebrews
Authors: Martin Michael W. , Whitlark Jason A.
Published: June 2011

This study examines comparison in Hebrews in the light of ancient rhetorical theory of syncrisis, identifying five epideictic syncrises: the messengers/angels vs. Jesus (1.1-14; 2.5-18), Moses vs. Jesus (3.1-6), the Aaronic high priests vs. Jesus (5.1-10), the Levitical priestly ministry vs. the Melchizedekian priestly ministry (7.1-10.18), and Mt. Sinai vs. Mt. Zion (12.18-24). The study shows that these comparisons collectively function as a single syncritical project that argues for the superiority of the new covenant to the old, and that the project, like most of the individual comparisons, is arranged topically in accordance with ancient rhetorical theory.
Gerontological autism: terms of accountability in the cultural study of the category of the Fourth Age
Authors: HAZAN HAIM
Published: June 2011

This paper poses an epistemological challenge to students and researchers of old age. It argues that people in deep old age are a testimony to the failure to generate a language by which to comprehend extra-cultural phenomena, which aborts a meaningful dialogue between researchers and subjects. The arguments put forward are based on an analysis of the unique position of the very old as an ultimate, unconstructable ‘other’, as they appear in the relevant anthropological discourse, and maintains that cultural standing of that category is anchored in a symbolic and existential space that prevents communication with its inhabitants. The social processes that lead to this state of absent translation and a deadlock of interpretation are analysed by using examples a longitudinal study of the oldest old conducted by the Herczeg Institute on Aging in Israel. An alternative option for a new conceptual articulation of ways of understanding ageing is proposed; one that is free of conventional but ineffectual paradigms.
Discriminant functions for isotropic configurations in robot manipulators
Authors: Duleba Ignacy
Published: June 2011

In this paper, a family of discriminant functions is defined for searching isotropic configurations in robot manipulators. A subfamily of the functions extensively exploits properties of symmetric polynomials derived from a manipulability matrix. The complexity analysis of computing the discriminant functions is provided. Possible applications of the functions are mentioned and illustrated.
Self-reported outcome measures in the health of older people: from research to standard clinical practice
Authors: El Miedany Yasser , Toth Mathias
Published: June 2011

Ageing is creating policy challenges for most developed countries and increasing the pressure on health and social care systems. The health status of patients is best described based on their own reports and quantitative data concerning factors such as functional disability, psychological status, pain, falls or cardiovascular risk, are critical to follow changes in patients’ condition and response to therapy. Standardized information concerning health status and co-morbidity risks can be collected easily and effectively from a ‘patient reported outcome measures (PROMs) questionnaire’ completed by the patient. Such data allow accurate description, months or years later, of changes in status. Without such records, neither the patient nor the health professional can remember the patient's earlier status reliably. This article will discuss the concept of PROMs and how they can be implemented into standard clinical practice.
Aortic mineralisation in children with congenital cardiac disease
Authors: Baños-González Manuel A. , Calderón-Colmenero Juan , Aranda-Fraustro Alberto , Peña-Duque Marco A. , Martínez-Ríos Marco A. , Valente-Acosta Benjamín , Linares-López Carlos , Delgado-Granados Hugo , de la Peña-Díaz Aurora
Published: June 2011

Background

Congenital cardiac diseases are the most frequent congenital malformations. In adult patients, the mineralisation of the aorta due to cardiovascular disease is very common, but vascular mineralisation in paediatric cardiopathies is a topic less studied. This study shows that children with a complex congenital cardiopathy show a high degree of vascular mineralisation in the ascending aorta. This can be part of the cardiac failure pathophysiology due to congenital cardiopathies.

Objective

The aim of this study was to determine the presence and degree of vascular mineralisation in samples of the ascending and descending aorta of children with complex congenital cardiopathies.

Design

We conducted a cross-sectional study.

Subjects

We obtained 34 vascular tissues from the autopsies of 17 children with congenital cardiac disease.

Methods

We used a scanning electron microscope with an energy-dispersive X-ray spectroscopy in order to analyse the vascular tissues.

Results

The amount of minerals was two times higher in the ascending aorta than in the descending aorta of children with congenital cardiac disease.

Conclusions

The study provides evidence that vascular mineralisation can start at an early age, and that it is higher in the ascending aorta than in the descending aorta.
Worry, Beliefs about Worry and Problem Solving in Young Children
Authors: Wilson Charlotte , Hughes Claire
Published: June 2011

Background: Childhood worry is common, and yet little is known about why some children develop pathological worry and others do not. Two theories of adult worry that are particularly relevant to children are Davey's problem-solving model in which perseverative worry occurs as a result of thwarted problem-solving attempts, and Wells’ metacognitive model, in which positive and negative beliefs about worry interact to produce pathological worry. Aims: The present study aimed to test hypotheses that levels of worry in young children are associated with poor or avoidant solution generation for social problems, and poor problem-solving confidence. It also aimed to explore beliefs about worry in this age group, and to examine their relationships with worry, anxiety and age. Method: Fifty-seven young children (6–10 years) responded to open ended questions about social problem-solving situations and beliefs about worry, and completed measures of worry, anxiety and problem-solving confidence. Results: Children with higher levels of worry and anxiety reported using more avoidant solutions in social problem situations and children's low confidence in problem solving was associated with high levels of worry. Children as young as 6 years old reported both positive and negative beliefs about worry, but neither were associated with age, gender, or level of anxiety or worry. Conclusions: Results indicate similarities between adults and children in the relationships between problem-solving variables and worry, but not in relationships between beliefs about worry and worry. This may be due to developmental factors, or may be the result of measurement issues.
The Bribery Act: What's all the Fuss About?
Authors: Bell Amy
Published: June 2011

Amy Bell examines the controversial Bribery Act which will come into effect on 1st July 2011 and why most businesses will have to prepare for it.
Visit to IALS Library: a Comparison with the Facilities of the Nigerian Institute of Advanced Legal Studies Library
Authors: Lamikanra Ufuoma
Published: June 2011

Ufuoma Lamikanra and Dr T. O. Dada visited the IALS library in March 2010 to study the running of a large academic library with a view to trying to modernise procedures in the Nigerian Institute's library.
Region-1 field aligned currents in experiments on laser-produced plasma interacting with magnetic dipole
Authors: Shaikhislamov I. F. , Zakharov Yu. P. , Posukh V. G. , Boyarintsev E. L. , Melekhov A. V. , Antonov V. M. , Ponomarenko A. G.
Published: June 2011

In previous experiments by the authors a generation of intense field aligned current (FAC) system on Terrella poles was observed. In the present report a question of these currents origin in a low latitude boundary layer of magnetosphere is investigated. Experimental evidence of such a link was obtained by measurements of magnetic field generated by tangential sheared drag. Results suggest that compressional and Alfven waves are responsible for FAC generation. The study is most relevant to FAC generation in the Earth and Hermean magnetospheres following pressure jumps in Solar Wind.
Magnetic fractures or reconnection of type II
Authors: Haerendel Gerhard
Published: June 2011

The importance of reconnection in astrophysics has been widely recognized. It is instrumental in storing and releasing magnetic energy, the latter often in a dramatic fashion. A closely related process, playing in very low beta plasmas, is much less known. It is behind the acceleration of auroral particles in the low-density environment several 1000 km above the Earth. It involves the appearance of field-parallel voltages in presence of intense field-aligned currents. The underlying physical process is the release of magnetic shear stresses and conversion of the liberated magnetic energy into kinetic energy of the particles creating auroral arcs. In this process, field lines disconnect from the field anchored in the ionosphere and reconnect to other field lines. Because of the stiffness of the magnetic field, the process resembles mechanical fractures. It is typically active in the low-density magnetosphere of planets. However, it can also lead to significant energy conversion with high-energy particle production and subsequent gamma ray emissions in stellar magnetic fields, in particular of compact objects.
Solar plasma generated by sungrazing comets
Authors: Ibodov F. S. , Ibadov S.
Published: June 2011

It is analytically shown that passages of comets near the Sun's surface with velocities more than 600 km/s is accompanied by aerodynamic crushing of their nuclei within the solar chromosphere and transversal expansion of the crushed matter. The deceleration of the flattened hypervelocity body within the solar photosphere has sharply impulsive and strongly explosive character. The specific energy release in the explosion zone near the solar surface 10-100 thousand times exceeds the evaporation heat of the nucleus material, so that the process is accompanied by generation of high-temperature plasma and non-stationary explosive phenomena around the photosphere. Spectral observations of these phenomena by SOHO and SDO type space observatories with high spatial and temporal resolutions are of interest for the plasma astrophysics as well as the physics of solar flares.
Helicity transport in a simulated coronal mass ejection
Authors: Kliem B. , Rust S. , Seehafer N.
Published: June 2011

It has been suggested that coronal mass ejections (CMEs) remove the magnetic helicity of their coronal source region from the Sun. Such removal is often regarded to be necessary due to the hemispheric sign preference of the helicity, which inhibits a simple annihilation by reconnection between volumes of opposite chirality. Here we monitor the relative magnetic helicity contained in the coronal volume of a simulated flux rope CME, as well as the upward flux of relative helicity through horizontal planes in the simulation box. The unstable and erupting flux rope carries away only a minor part of the initial relative helicity; the major part remains in the volume. This is a consequence of the requirement that the current through an expanding loop must decrease if the magnetic energy of the configuration is to decrease as the loop rises, to provide the kinetic energy of the CME.
Separation of solar radio bursts in a complex spectrum
Authors: Mészárosová Hana , Rybák Ján , Karlický Marian , Jiřička Karel
Published: June 2011

Radio spectra, observed during solar flares, are usually very complex (many bursts and fine structures). We have developed a new method to separate them into individual bursts and analyze them separately. The method is used in the analysis of the 0.8–2.0 GHz radio spectrum of the April 11, 2001 event, which was rich in drifting pulsating structures (DPSs). Using this method we showed that the complex radio spectrum consists of at least four DPSs separated with respect to their different frequency drifts (−115, −36, −23, and −11 MHz s−1). These DPSs indicate a presence of at least four plasmoids expected to be formed in a flaring current sheet. These plasmoids produce the radio emission on close frequencies giving thus a mixture of superimposed DPSs observed in the radio spectrum.
A way to detect the magnetic helicity using the observable polarized radio emission
Authors: Stepanov Rodion , Volegova Antonina
Published: June 2011

We discuss inverse problem of detection turbulence magnetic field helical properties using radio survey observations statistics. In this paper, we present principal solution which connects magnetic helicity and correlation between Faraday rotation measure and polarization degree of radio synchrotron emission. The effect of depolarization plays the main role in this problem and allows to detect magnetic helicity for certain frequency range of observable radio emission. We show that the proposed method is mainly sensitive to a large-scale magnetic field component.
Unveiling the butterfly diagram structure
Authors: Ternullo Maurizio
Published: June 2011

A Butterfly Diagram showing the spotted area distribution is presented. The diagram reveals that most of the spotted area is concentrated in few, small portions (“knots”) of the butterfly wings. A knot may appear at either lower or higher latitudes than previous ones, in a seemingly random way; accordingly, the spot mean latitude abruptly drifts equatorward or even poleward at any knot activation, in spite of any smoothing procedure. The description, assuming that spots scatter around the “spot mean latitude” steadily drifting equatorward, is questioned. In a relevant number of cases, knots appear to be arranged in two roughly parallel, oblique streams, the “spot mean latitude” being located in the underspotted band lying between these streams.
Alfvén resonance absorption in electron-positron plasmas
Authors: Cramer N. F.
Published: June 2011

Waves propagating obliquely in a magnetized cold pair plasma experience an approximate resonance in the wavevector component perpendicular to the magnetic field, which is the analogue of the Alfvén resonance in normal electron-ion plasmas. Wave absorption at the resonance can take place via mode conversion to the analogue of the short wavelength inertial Alfvén wave. The Alfvén resonance could play a role in wave propagation in the pulsar magnetosphere leading to pulsar radio emission. Ducting of waves in strong plasma gradients may occur in the pulsar magnetosphere, which leads to the consideration of Alfvén surface waves, whose energy is concentrated in the region of strong gradients.
GRB spectral parameter modeling
Authors: Fleishman Gregory D. , Urtiev Fedor A.
Published: June 2011

Fireball model of the gamma-ray bursts (GRBs) predicts generation of numerous internal shocks, which efficiently accelerate charged particles and generate relatively small-scale stochastic magnetic and electric fields. The accelerated particles diffuse in space due to interaction with the random waves and so emit so called Diffusive Synchrotron Radiation (DSR) in contrast to standard synchrotron radiation they would produce in a large-scale regular magnetic fields. In this contribution we present key results of detailed modeling of the GRB spectral parameters, which demonstrate that the non-perturbative DSR emission mechanism in a strong random magnetic field is consistent with observed distributions of the Band parameters and also with cross-correlations between them.
Current instabilities in the pulsar magnetosphere
Authors: Jessner Axel , Lesch Harald , Kramer Michael
Published: June 2011

Pulsars are rotating neutron stars with strong magnetic dipole fields (B = 104 − 109T), and high induced surface potentials (ca. 1014V). A strong charged particle current is driven out of the polar cap. It returns along an equatorial current sheet. The total dissipated power of the current system is a significant fraction of the observed spin-down power of the pulsar. The Pierce instability occurs when particles are constrained to move in only one dimension and the field from the accumulated space charge exceeds the accelerating background field. Relativistic particle motion enhances the instability which forms narrow regions (cm) of high particle densities and low velocities separated by much longer but more tenuous relativistic flows. The calculated spectrum, power budget and time scales of the magnetospheric Pierce instabilities match the observed radio properties of pulsars.
Two component relativistic acceleration and polarized radiation of the parsec-scale AGN jet
Authors: Porth Oliver
Published: June 2011

We perform axisymmetric simulations of two-component jet acceleration using the special relativistic MHD code PLUTO (Mignone et al., 2007). The inner, thermally driven component constitutes a dilute relativistic plasma originating in a high enthalpy central corona. The second component is a Poynting-dominated wind driven by a global current system. Once a near-stationary state is reached, we solve the polarized Synchrotron radiation transport incorporating self-absorption and (internal) Faraday rotation. With this approach we obtain high-resolution radio maps and spectra that can help in the interpretation of observational data from nearby active galactic nuclei by predicting spine-sheath polarization structures and Faraday rotation gradients.
Particle acceleration in Blazars
Authors: Weidinger Matthias , Spanier Felix
Published: June 2011

Understanding the variable emission of blazars observed with gamma-ray telescopes and Fermi has become a major challenge for theoretical models of particle acceleration. Here, we introduce a novel time-dependent emission model in which the maximum energy of particles is determined from a balance between Fermi type I and II acceleration energy gains and radiative energy losses, allowing for an explanation of both the characteristic spectral energy distribution of blazars and their intrinsic sub-hour variability. Additionally, we can determine the physical condition of the emitting plasma concerning its turbulence and typical shock speeds.
Towards observational MHD. Advances in spectropolarimetry and the prospects for the E-ELT
Authors: Strassmeier Klaus G.
Published: June 2011

Polarization and wavelength are the bits of information attached to every photon that reveal the most about its formation and subsequent history. The E-ELT will, for the foreseeable future, be the most powerful optical light-collecting machine ever built. The strength of its combination, spectropolarimetry with the E-ELT, is the anchorage in physics of astronomical observations. I present a strawman design of a spectropolarimeter for its intermediate focus.
Investigations of solar plasma in the interior and corona from Solar Dynamics Observatory
Authors: Kosovichev A. G.
Published: June 2011

The Sun is a plasma laboratory for astrophysics, which allows us to investigate many important phenomena in turbulent magnetized plasma in detail. Solar Dynamics Observatory (SDO) launched in February 2010 provides unique information about plasma processes from the interior to the corona. The primary processes of magnetic field generation and formation of magnetic structures are hidden beneath the visible surface. Helioseismic diagnostics, based on observations and analysis of solar oscillations and waves, give insights into the physical processes in the solar interior and mechanisms of solar magnetic activity. In addition, simultaneous high-resolution multi-wavelength observations of the solar corona provide opportunity to investigate in unprecedented detail the coronal dynamics and links to the interior processes. These capabilities are illustrated by initial results on the large-scale dynamics of the Sun, the subsurface structure and dynamics of a sunspot and observations of a X-class solar flare.
Inclusion of velocity gradients in the Unno solution for magnetic field diagnostic from spectropolarimetric data
Authors: Molodij Guillaume , Bommier Véronique
Published: June 2011

We present an extension of the Unno-Rachkovsky solution that provides the theoretical profiles coming out of a Milne-Eddington atmosphere imbedded in a magnetic field, to the additional taking into account of a vertical velocity gradient. Thus, the theoretical profiles may display asymmetries as do the observed profiles, which facilitates the inversion based on the Unno-Rachkovsky theory, and leads to the additional determination of the vertical velocity gradient. We present UNNOFIT inversion on spectropolarimetric data performed on an active region of the Sun with the french-italian telescope THEMIS operated by CNRS and CNR on the island of Tenerife.
“Ambipolar diffusion” and magnetic reconnection
Authors: Tsap Yuriy T. , Stepanov Alexander V.
Published: June 2011

Based on the three-fluid approximation the influence of the neutral component of hydrogen plasma on Joule dissipation of electric currents are considered. As distinguished from Mestel & Spitzer (1956) and Parker (1963) it has been shown that the magnetic flux may be not conserved in the case of the “ambipolar diffusion” due to collisions between ions and neutrals. This is explained by the ion acceleration under the action of Ampere's force. Joule dissipation is determined by electron and ion collisions in a partially ionized plasma. Plasma evacuation from current sheets is the effective mechanism of its cooling. Thickness of a current sheet can achieve up to hundreds of kilometers in the solar chromosphere. The origin of the solar chromospheric jets observed with the Hinode satellite are discussed.
Plasmoid ejections driven by dynamo action underneath a spherical surface
Authors: Warnecke Jörn , Brandenburg Axel , Mitra Dhrubaditya
Published: June 2011

We present a unified three-dimensional model of the convection zone and upper atmosphere of the Sun in spherical geometry. In this model, magnetic fields, generated by a helically forced dynamo in the convection zone, emerge without the assistance of magnetic buoyancy. We use an isothermal equation of state with gravity and density stratification. Recurrent plasmoid ejections, which rise through the outer atmosphere, is observed. In addition, the current helicity of the small–scale field is transported outwards and form large structures like magnetic clouds.
Optimized gyrosynchrotron algorithms and fast codes
Authors: Kuznetsov Alexey A. , Fleishman Gregory D.
Published: June 2011

Gyrosynchrotron (GS) emission of charged particles spiraling in magnetic fields plays an exceptionally important role in astrophysics. In particular, this mechanism makes a dominant contribution to the continuum solar and stellar radio emissions. However, the available exact equations describing the emission process are extremely slow computationally, thus limiting the diagnostic capabilities of radio observations. In this work, we present approximate GS codes capable of fast calculating the emission from anisotropic electron distributions. The computation time is reduced by several orders of magnitude compared with the exact formulae, while the computation error remains within a few percent. The codes are implemented as the executable modules callable from IDL; they are made available for users via web sites.
Development of the theory of instabilities of differentially rotating plasma with astrophysical applications
Authors: Lominadze J. G.
Published: June 2011

Instabilities of nonuniform flows is a fundamental problem in dynamics of fluids and plasmas. This presentation outlines atypical dynamics of instabilities for unmagnetized and magnetized astrophysical differentially rotating flows, including, our efforts in the development of general theory of magneto rotation instability (MRI) that takes into account plasma compressibility, pressure anisotropy, dissipative and kinetic effects. Presented analysis of instability (transient growth) processes in unmagnetized/hydrodynamic astrophysical disks is based on the breakthrough of the hydrodynamic community in the 1990s in the understanding of shear flow non-normality induced dynamics. This analysis strongly suggests that the so-called bypass concept of turbulence, which has been developed by the hydrodynamic community for spectrally stable shear flows, can also be applied to Keplerian disks. It is also concluded that the vertical stratification of the disks is an important ingredient of dynamical processes resulting onset of turbulence.
MHD turbulence-Star Formation Connection: from pc to kpc scales
Authors: de Gouveia Dal Pino E. M. , Santos-Lima R. , Lazarian A. , Leão M. R. M. , Falceta-Gonçalves D. , Kowal G.
Published: June 2011

The transport of magnetic flux to outside of collapsing molecular clouds is a required step to allow the formation of stars. Although ambipolar diffusion is often regarded as a key mechanism for that, it has been recently argued that it may not be efficient enough. In this review, we discuss the role that MHD turbulence plays in the transport of magnetic flux in star forming flows. In particular, based on recent advances in the theory of fast magnetic reconnection in turbulent flows, we will show results of three-dimensional numerical simulations that indicate that the diffusion of magnetic field induced by turbulent reconnection can be a very efficient mechanism, especially in the early stages of cloud collapse and star formation. To conclude, we will also briefly discuss the turbulence-star formation connection and feedback in different astrophysical environments: from galactic to cluster of galaxy scales.
Relativistic plasma and ICM/radio source interaction
Authors: Feretti Luigina , Giovannini Gabriele , Govoni Federica , Murgia Matteo
Published: June 2011

The first detection of a diffuse radio source in a cluster of galaxies, dates back to the 1959 (Coma Cluster, Large et al. 1959). Since then, synchrotron radiating radio sources have been found in several clusters, and represent an important cluster component which is linked to the thermal gas. Such sources indicate the existence of large scale magnetic fields and of a population of relativistic electrons in the cluster volume. The observational results provide evidence that these phenomena are related to turbulence and shock-structures in the intergalactic medium, thus playing a major role in the evolution of the large scale structure in the Universe. The interaction between radio sources and cluster gas is well established in particular at the center of cooling core clusters, where feedback from AGN is a necessary ingredient to adequately describe the formation and evolution of galaxies and host clusters.
Supernova-driven interstellar turbulence and the galactic dynamo
Authors: Gressel Oliver , Elstner Detlef , Rüdiger Günther
Published: June 2011

The fractal shape and multi-component nature of the interstellar medium together with its vast range of dynamical scales provides one of the great challenges in theoretical and numerical astrophysics. Here we will review recent progress in the direct modelling of interstellar hydromagnetic turbulence, focusing on the role of energy injection by supernova explosions. The implications for dynamo theory will be discussed in the context of the mean-field approach.

Results obtained with the test field-method are confronted with analytical predictions and estimates from quasilinear theory. The simulation results enforce the classical understanding of a turbulent Galactic dynamo and, more importantly, yield new quantitative insights. The derived scaling relations enable confident global mean-field modelling.
Statistical tools of interstellar turbulence: connecting observations with theory
Authors: Burkhart B. , Lazarian A.
Published: June 2011

MHD Turbulence is a critical component of the current paradigms of star formation, particle transport, magnetic reconnection and evolution of the ISM, to name just a few. Progress on this difficult subject is made via numerical simulations and observational studies, however in order to connect these two, statistical methods are required. This calls for new statistical tools to be developed in order to study turbulence in the interstellar medium. Here we briefly review some of the recently developed statistics that focus on characterizing gas compressibility and magnetization and their uses to interstellar studies.
The fate of magnetic fields in colliding galaxies
Authors: Kotarba Hanna , Lesch Harald , Dolag Klaus , Naab Thorsten
Published: June 2011

The evolution and amplification of large-scale magnetic fields in galaxies is investigated by means of high resolution simulations of interacting galaxies. The goal of our project is to consider in detail the role of gravitational interaction of galaxies for the fate of magnetic fields. Since the tidal interaction up to galaxy merging is a basic ingredient of cold-dark matter (CDM) structure formation models we think that our simulations will give important clues for the interplay of galactic dynamics and magnetic fields.
Ferromagnetic properties of charged vector bosons condensate in the early universe
Authors: Piccinelli Gabriella
Published: June 2011

Bose-Einstein condensation in the early universe is considered. The magnetic properties of a condensate of charged vector bosons are studied, showing that a ferromagnetic state is formed. As a consequence, the primeval plasma may be spontaneously magnetized inside macroscopically large domains and primordial magnetic fields can be generated.
General relativistic magnetic perturbations and dynamo effects in extragalactic radiosources
Authors: de Andrade L. C. Garcia
Published: June 2011

By making use of the MHD self-induction equation in general relativity (GR), recently derived by Clarkson and Marklund (2005), it is shown that when Friedmann universe possesses a spatial section whose Riemannian curvature is negative, the magnetic energy bounds computed by Nuñez (2002) also bounds the growth rate of the magnetic field given by the strain matrix of dynamo flow. Since in GR-MHD dynamo equation, the Ricci tensor couples with the universe magnetic field, only through diffusion, and most ages are highly conductive the interest is more theoretical here, and only very specific plasma astrophysical problems can be address such as in laboratory plasmas. Magnetic fields and the negative curvature of some isotropic cosmologies, contribute to enhence the amplification of the magnetic field. Ricci curvature energy is shown to add to strain matrix of the flow, to enhance dynamo action in the universe. Magnetic fluctuations of the Clarkson-Marklund equations for a constant magnetic field seed in highly conductive flat universes, leads to a magnetic contrast of ≈ 2, which is well within observational limits from extragalactic radiosources of ≈ 1.7. In the magnetic helicity fluctuations the magnetic contrast shows that the dynamo effects can be driven by these fluctuations.
Cosmic ray driven dynamo in barred and ringed galaxies
Authors: Kulpa-Dybeł K. , Otmianowska-Mazur K. , Kulesza-Żydzik B. , Kowal G. , Wóltański D. , Hanasz M. , Kowalik K.
Published: June 2011

We study the global evolution of the magnetic field and interstellar medium (ISM) of the barred and ringed galaxies in the presence of non-axisymmetric components of the potential, i.e. the bar and/or the oval perturbations. The magnetohydrodynamical dynamo is driven by cosmic rays (CR), which are continuously supplied to the disk by supernova (SN) remnants. Additionally, weak, dipolar and randomly oriented magnetic field is injected to the galactic disk during SN explosions. To compare our results directly with the observed properties of galaxies we construct realistic maps of high-frequency polarized radio emission. The main result is that CR driven dynamo can amplify weak magnetic fields up to few μG within few Gyr in barred and ringed galaxies. What is more, the modelled magnetic field configuration resembles maps of the polarized intensity observed in barred and ringed galaxies.
Three dimensional simulations of Hall magnetohydrodynamics
Authors: Gómez Daniel O.
Published: June 2011

Turbulent flows take place in a large variety of astrophysical objects, and often times are the source of dynamo generated magnetic fields. Much of the progress in our understanding of dynamo mechanisms, has been made within the theoretical framework of magnetohydrodynamics (MHD). However, for sufficiently diffuse media, the Hall effect eventually becomes non-negligible.

We present results from simulations of the Hall-MHD equations. The simulations are performed with a pseudospectral code to achieve exponentially fast convergence. We study the role of the Hall effect in the dynamo efficiency for different values of the Hall parameter.
Shock refraction from classical gas to relativistic plasma environments
Authors: Keppens Rony , Delmont Peter , Meliani Zakaria
Published: June 2011

The interaction of (strong) shock waves with localized density changes is of particular relevance to laboratory as well as astrophysical research. Shock tubes have been intensively studied in the lab for decades and much has been learned about shocks impinging on sudden density contrasts. In astrophysics, modern observations vividly demonstrate how (even relativistic) winds or jets show complex refraction patterns as they encounter denser interstellar material.

In this contribution, we highlight recent insights into shock refraction patterns, starting from classical up to relativistic hydro and extended to magnetohydrodynamic scenarios. Combining analytical predictions for shock refraction patterns exploiting Riemann solver methodologies, we confront numerical, analytical and (historic) laboratory insights. Using parallel, grid-adaptive simulations, we demonstrate the fate of Richtmyer-Meshkov instabilities when going from gaseous to magnetized plasma scenarios. The simulations invoke idealized configurations closely resembling lab analogues, while extending them to relativistic flow regimes.
Formation of electron clouds during particle acceleration in a 3D current sheet
Authors: Zharkova Valentina V. , Siversky Taras
Published: June 2011

Acceleration of protons and electrons in a reconnecting current sheet (RCS) is investigated with the test particle and particle-in-cell (PIC) approaches in the 3D magnetic configuration including the guiding field. PIC simulations confirm a spatial separation of electrons and protons towards the midplane and reveal that this separation occur as long as protons are getting accelerated. During this time electrons are ejected into their semispace of the current sheet moving away from the midplane to distances up to a factor of 103 – 104 of the RCS thickness and returning back to the RCS. This process of electron circulation around the current sheet midplane creates a cloud of high energy electrons around the current sheet which exists as long as protons are accelerated. Only after protons gain sufficient energy to break from the magnetic field of the RCS, they are ejected to the opposite semispace dragging accelerated electrons with them. These clouds can be the reason of hard X-ray emission in coronal sources observed by RHESSI.
Magnetic helicity fluxes in αΩ dynamos
Authors: Candelaresi Simon , Brandenburg Axel
Published: June 2011

In turbulent dynamos the production of large-scale magnetic fields is accompanied by a separation of magnetic helicity in scale. The large- and small-scale parts increase in magnitude. The small-scale part can eventually work against the dynamo and quench it, especially at high magnetic Reynolds numbers. A one-dimensional mean-field model of a dynamo is presented where diffusive magnetic helicity fluxes within the domain are important. It turns out that this effect helps to alleviate the quenching. Here we show that internal magnetic helicity fluxes, even within one hemisphere, can be important for alleviating catastrophic quenching.
Current-Driven Kink Instability in Relativistic Jets
Authors: Mizuno Yosuke , Hardee Philip E. , Lyubarsky Yuri , Nishikawa Ken-Ici
Published: June 2011

We have investigated the development of current-driven (CD) kink instability in relativistic jets via 3D RMHD simulations. In this investigation a static force-free equilibrium helical magnetic field configuration is considered in order to study the influence of the initial configuration on the linear and nonlinear evolution of the instability. We found that the initial configuration is strongly distorted but not disrupted by the CD kink instability. The linear growth and nonlinear evolution of the CD kink instability depends moderately on the radial density profile and strongly on the magnetic pitch profile. Kink amplitude growth in the nonlinear regime for decreasing magnetic pitch leads to a slender helically twisted column wrapped by magnetic field. On the other hand, kink amplitude growth in the nonlinear regime nearly ceases for increasing magnetic pitch.
Connexin Channels Provide a Target to Manipulate Brain Endothelial Calcium Dynamics and Blood—Brain Barrier Permeability
Authors: De Bock Marijke , Culot Maxime , Wang Nan , Bol Mélissa , Decrock Elke , De Vuyst Elke , da Costa Anaelle , Dauwe Ine , Vinken Mathieu , Simon Alexander M , Rogiers Vera , De Ley Gaspard , Evans William Howard , Bultynck Geert , Dupont Geneviève , Cecchelli Romeo , Leybaert Luc
Published: June 2011

The cytoplasmic Ca2+ concentration ([Ca2+]i) is an important factor determining the functional state of blood-brain barrier (BBB) endothelial cells but little is known on the effect of dynamic [Ca2+]i changes on BBB function. We applied different agonists that trigger [Ca2+]i oscillations and determined the involvement of connexin channels and subsequent effects on endothelial permeability in immortalized and primary brain endothelial cells. The inflammatory peptide bradykinin (BK) triggered [Ca2+]i oscillations and increased endothelial permeability. The latter was prevented by buffering [Ca2+]i with BAPTA, indicating that [Ca2+]i oscillations are crucial in the permeability changes. Bradykinin-triggered [Ca2+]i oscillations were inhibited by interfering with connexin channels, making use of carbenoxolone, Gap27, a peptide blocker of connexin channels, and Cx37/43 knockdown. Gap27 inhibition of the oscillations was rapid (within minutes) and work with connexin hemichannel-permeable dyes indicated hemichannel opening and purinergic signaling in response to stimulation with BK. Moreover, Gap27 inhibited the BK-triggered endothelial permeability increase in in vitro and in vivo experiments. By contrast, [Ca2+]i oscillations provoked by exposure to adenosine 5’ triphosphate (ATP) were not affected by carbenoxolone or Gap27 and ATP did not disturb endothelial permeability. We conclude that interfering with endothelial connexin hemichannels is a novel approach to limiting BBB-permeability alterations.
Protein Therapy Using Heme-Oxygenase-1 Fused to a Polyarginine Transduction Domain Attenuates Cerebral Vasospasm after Experimental Subarachnoid Hemorrhage
Authors: Ogawa Tomoyuki , Hänggi Daniel , Wu Yumei , Michiue Hiroyuki , Tomizawa Kazuhito , Ono Shigeki , Matsui Hideki , Date Isao , Steiger Hans-Jakob
Published: June 2011

A sequence of 11 consecutive arginine residues (11R) is one of the best protein transduction domains for introducing proteins into cell membranes. Heme-oxygenase-1 (HO-1) is involved in heme catabolism and reduces the contractile effect of hemoglobin after subarachnoid hemorrhage (SAH). Therefore, we constructed 11R-fused HO-1 protein to achieve successful transduction of the protein into the cerebral arteries and examined the therapeutic effect of the 11R-HO-1 protein for cerebral vasospasm (CV) after SAH. We injected the 11R-HO-1 protein into the cisterna magna of male rats and, several hours after the injection, performed immunofluorescence staining and western blotting analysis of the rat basilar arteries (BAs) to determine transduction efficacy. We also assessed intraarterial HO-1 activity as cGMP (cyclic guanosine 3′, 5′-cyclic monophosphate) accumulation in SAH and determined whether protein transduction of 11R-HO-1 quantified the therapeutic effect in a rat double-hemorrhage model of SAH. The BAs expressed significantly more HO-1 in the group injected with 11R-HO-1 (3.56±0.54 (11R-HO-1) versus control (saline)), and transduction of 11R-HO-1 resulted in higher activity (>3.25-fold) in rat BAs with SAH. Moreover, the results of the rat double-hemorrhage model showed that the 11R-HO-1 protein significantly attenuated CV after SAH (317.59±23.48 μm (11R-HO-1) versus 270.08±14.66 μm (11R-fused enhanced green fluorescent protein), 252.05±13.95 μm (saline), P<0.01).
Academic Administration: Essential Characteristics and Attributes of Speech-Language Pathologists
Authors: O’Rourke Colleen M.
Published: June 2011

In 2007, the Council of Academic Programs in Communication Sciences and Disorders (CAPCSD) developed a list of Eligibility Requirements and Essential Functions for students interested in the field of speech-language pathology (Schwartz et al., 2007). Based on this comprehensive list of skills and attributes, the graduate program at Georgia State University developed a core set of characteristics for speech-language pathology students. The list focuses on skills and attributes students should demonstrate prior to the start of a graduate program in speech-language pathology. This article summarizes the process used to develop the list and discusses the importance of institutions creating unique lists for their respective programs.
Supervision: Supervision in Early Intervention: An Inside-Out Perspective
Authors: McGinley Kimberly A. , Robke Darlene D.
Published: June 2011

This article outlines the roles and perspectives of the clinician and supervisor within an Early Intervention (EI) model and how they differ from a center-based model. The varied models, guidelines, and challenges that affect EI practice are reviewed. A unique “inside-out” supervisory perspective/approach is emphasized. The influence of relationships upon services and supervision, as well as the importance of reflective practice, is addressed.
Ethical Considerations for Conducting Clinical Research
Authors: Suiter Debra M.
Published: June 2011

The need for evidence-based assessments and treatments for individuals with dysphagia has driven the need for more research in these areas. This article reviews the history of research ethics and the documents that have shaped the public's perception of clinical research, and discusses specific examples of how these ethics affect clinical research of individuals with dysphagia.
iTherapy: The Revolution of Mobile Devices Within the Field of Speech Therapy
Authors: Fernandes Barbara
Published: June 2011

The iPhone®, iPod touch® and the iPad® are becoming widely used as therapy tools. This article will introduce the devices' basic features that can be used by speech-language pathologists (SLPs) to support service delivery in schools, report the results of a survey addressing current use and implementation of the devices in the school setting, introduce basic concepts behind applications for speech and language therapy, and guide SLPs when choosing accessories for the devices that will be used for therapy. The iDevices have made the use of technology within the field of speech pathology affordable, convenient, and user-friendly, key features for the adoption of any new tool.

(Note: iPhone®, iPod touch® and iPad® are registered trademarks of Apple Inc.)
Teaching Social Skills Using Video Modeling Interventions
Authors: Whalen Christina , Franke Lauren , Lara-Brady Laura
Published: June 2011

Difficulty with social skills is a distinctive characteristic of many students with special needs, even those with mild disabilities. The literature supports many approaches to teaching social skills, yet many of these interventions require one-on-one intensive training for implementation, and/or are being conducted in laboratory or clinical settings rather than in naturalistic environments. As technology is becoming a growing component of social skills intervention through the use of Smartboards, Ipads, computers, and other electronic devices, an increasingly popular method with equal support from the literature is the use of video modeling—a demonstration of a desired behavior that the student imitates. The purpose of this article is to describe Bandura's (1977) view of learning and how this theory relates to the use of video modeling for the purpose of social skills intervention. The authors also will provide an overview of current products that are available to provide social skills intervention using video modeling.
Relationship between Q-factor and sample damping for contact resonance atomic force microscope measurement of viscoelastic properties
Authors: Yuya P. A. , Hurley D. C. , Turner J. A.
Published: June 2011

Contact resonance AFM characterization techniques rely on the dynamics of the cantilever as it vibrates while in contact with the sample. In this article, the dependence of the quality factor of the vibration modes on the sample properties is shown to be a complex combination of beam and sample properties as well as the applied static tip force. Here the tip-sample interaction is represented as a linear spring and viscous dashpot as a model for sample (or contact) stiffness and damping. It is shown that the quality factor alone cannot be used to infer the damping directly. Experimental results for polystyrene and polypropylene are found to be in good agreement with predictions from the model developed. These results form the basis for mapping viscoelastic properties with nanoscale resolution.