Strong ExB shear flows in the pedestal region in H-mode plasma

We report the first experimental observation of stationary zonal flows in the pedestal region of the H-mode plasma in the H-1 toroidal heliac. Strong peaks in E_r shear mark the top and foot of the density pedestal. Strong m=n=0 low-frequency (f < 0.6 kHz) zonal flows are observed in regions of increased E_r, suggesting substantial contribution of zonal flows to the spatial modulation of E_r radial profiles. Radial localization of zonal flows is correlated with a region of zero magnetic shear and low-order (7/5) rational surfaces.Comment: 4 pages, 5 figure

Self-organization in turbulence as a route to order in plasma and fluids

Transitions from turbulence to order are studied experimentally in thin fluid layers and magnetically confined toroidal plasma. It is shown that turbulence self-organizes through the mechanism of spectral condensation. The spectral redistribution of the turbulent energy leads to the reduction in the turbulence level, generation of coherent flow, reduction in the particle diffusion and increase in the system's energy. The higher order state is sustained via the nonlocal spectral coupling of the linearly unstable spectral range to the large-scale mean flow. The similarity of self-organization in two-dimensional fluids and low-to-high confinement transitions in plasma suggests the universality of the mechanism.Comment: 5 pages, 4 figure

Action minimizing fronts in general FPU-type chains

We study atomic chains with nonlinear nearest neighbour interactions and prove the existence of fronts (heteroclinic travelling waves with constant asymptotic states). Generalizing recent results of Herrmann and Rademacher we allow for non-convex interaction potentials and find fronts with non-monotone profile. These fronts minimize an action integral and can only exists if the asymptotic states fulfil the macroscopic constraints and if the interaction potential satisfies a geometric graph condition. Finally, we illustrate our findings by numerical simulations.Comment: 19 pages, several figure

Stochastic dynamics and control of a driven nonlinear spin chain: the role of Arnold diffusion

We study a chain of non-linear, interacting spins driven by a static and a time-dependent magnetic field. The aim is to identify the conditions for the locally and temporally controlled spin switching. Analytical and full numerical calculations show the possibility of stochastic control if the underlying semi-classical dynamics is chaotic. This is achievable by tuning the external field parameters according to the method described in this paper. We show analytically for a finite spin chain that Arnold diffusion is the underlying mechanism for the present stochastic control. Quantum mechanically we consider the regime where the classical dynamics is regular or chaotic. For the latter we utilize the random matrix theory. The efficiency and the stability of the non-equilibrium quantum spin-states are quantified by the time-dependence of the Bargmann angle related to the geometric phases of the states.Comment: Journal-ref: to appear in J.Phys.

Topological Alterations of the Structural Brain Connectivity Network in Children with Juvenile Neuronal Ceroid Lipofuscinosis

BACKGROUND AND PURPOSE: We used diffusion MR imaging to investigate the structural brain connectivity networks in juvenile neuronal ceroid lipofuscinosis, a neurodegenerative lysosomal storage disease of childhood. Although changes in conventional MR imaging are typically not visually apparent in children agedPeer reviewe

A heavy quark effective field lagrangian keeping particle and antiparticle mixed sectors

We derive a tree-level heavy quark effective Lagrangian keeping particle-antiparticle mixed sectors allowing for heavy quark-antiquark pair annihilation and creation. However, when removing the unwanted degrees of freedom from the effective Lagrangian one has to be careful in using the classical equations of motion obeyed by the effective fields in order to get a convergent expansion on the reciprocal of the heavy quark mass. Then the application of the effective theory to such hard processes should be sensible for special kinematic regimes as for example heavy quark pair production near threshold.Comment: LaTeX, 14 pages, 1 EPS figure

Quasi-Two-Dimensional Dynamics of Plasmas and Fluids

In the lowest order of approximation quasi-twa-dimensional dynamics of planetary atmospheres and of plasmas in a magnetic field can be described by a common convective vortex equation, the Charney and Hasegawa-Mirna (CHM) equation. In contrast to the two-dimensional Navier-Stokes equation, the CHM equation admits "shielded vortex solutions" in a homogeneous limit and linear waves ("Rossby waves" in the planetary atmosphere and "drift waves" in plasmas) in the presence of inhomogeneity. Because of these properties, the nonlinear dynamics described by the CHM equation provide rich solutions which involve turbulent, coherent and wave behaviors. Bringing in non ideal effects such as resistivity makes the plasma equation significantly different from the atmospheric equation with such new effects as instability of the drift wave driven by the resistivity and density gradient. The model equation deviates from the CHM equation and becomes coupled with Maxwell equations. This article reviews the linear and nonlinear dynamics of the quasi-two-dimensional aspect of plasmas and planetary atmosphere starting from the introduction of the ideal model equation (CHM equation) and extending into the most recent progress in plasma turbulence.U. S. Department of Energy DE-FG05-80ET-53088Ministry of Education, Science and Culture of JapanFusion Research Cente

The HQET/NRQCD Lagrangian to order alpha/m^3

The HQET/NRQCD Lagrangian is computed to order alpha/m^3. The computation is performed using dimensional regularization to regulate the ultraviolet and infrared divergences. The results are consistent with reparametrization invariance to order 1/m^3. Some subtleties in the matching conditions for NRQCD are discussed.Comment: Two terms added to Lagrangian. Explicit value of G^3 coefficient given. Some references added, and TeX problems fixed. (18 pages, uses revtex

Moorella stamsii sp. nov., a new anaerobic thermophilic hydrogenogenic carboxydotroph isolated from digester sludge

A novel anaerobic, thermophilic, carbon monoxide-utilizing bacterium, strain E3-O, was isolated from anaerobic sludge of a municipal solid waste digester. Cells were straight rods, 0.6 to 1μm in diameter and 2 to 3 μm in length, growing as single cells or in pairs. Cells formed round terminal endospores. The temperature range for growth was 50 to 70°C, with an optimum at 65°C. The pH range for growth was 5.7 to 8.0, with an optimum at 7.5. Strain E3-O had the capability to ferment various sugars, such as fructose, galactose, glucose, mannose, raffinose, ribose, sucrose and xylose, producing mainly H2 and acetate. In addition, the isolate was able to grow with CO as the sole carbon and energy source. CO oxidation was coupled to H2 and CO2 formation. The G+C content of the genomic DNA was 54.6 mol %. Based on 16S rRNA gene sequence analysis, this bacterium is most closely related to Moorella glycerini (97% sequence identity). Based on the physiological features and phylogenetic analysis, it is proposed that strain E3-O should be classified in the genus Moorella as a new species, Moorella stamsii. The type strain of Moorella stamsii is E3-OT (=DMS 26271T=CGMCC 1.5181T).This work was possible through the financial support provided by the Portuguese Science Foundation (FCT) and the European Social Fund (POPH-QREN) through a PhD grant SFRH/BD/48965/2008 to J.I.A

Grief experiences among female American and Arab undergraduate college students

© 2015 The Author(s). The purpose of this study was to compare the incidence of grief among American and Arab female undergraduate students, the effects of their grief, and risk of prolonged grief disorder. A total of 471 female undergraduate students, 308 (65.4%) from the United Arab Emirates and 163 (34.6%) from the United States, completed a survey about their grief experiences. Students experiencing a significant loss also completed the Prolonged Grief Disorder Questionnaire. Findings revealed that overall approximately 38.4% (n=181) of all 471 students experienced the loss of a significant person in their lives within the past 24 months; a similar percentage was found in each sub group. Students reported various grief effects with American students experiencing more effects related to sleep, relationships, academics, physical well-being, religion/spirituality, and outlook on life than Arab students. Only a small number (10, 5.52%) of students met the criteria for prolonged grief disorder; however, most students were female Arab students. Limitations of the study and recommendations for future research are provided