bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regular aerobic exercise protects against impaired fasting plasma glucose-associated vascular endothelial dysfunction with aging
Authors: DeVan Allison E. , Eskurza Iratxe , Pierce Gary L. , Walker Ashley E. , Jablonski Kristen L. , Kaplon Rachelle E. , Seals Douglas R. 
Published: October 2012

In the present study, we tested the hypothesis that age-associated vascular endothelial dysfunction is exacerbated by IFG (impaired fasting plasma glucose) and that regular aerobic exercise prevents this effect. Data were analysed from a cohort of 131 non-smoking men and women without overt clinical disease. Compared with young adult controls (age=24±1 years, n=29; values are means±S.E.M.), brachial artery FMD (flow-mediated dilation), a measure of conduit artery EDD (endothelium-dependent dilation), was 33% lower [7.93±0.33 against 5.27±0.37%Δ (% change), P&lt;0.05] in MA/O (middle-aged/older) adults with NFG (normal fasting plasma glucose) (≤99 mg/dl, 62±1 years, n=35). In MA/O adults with IFG (100–125 mg/dl, 64±1 years, n=28), FMD was 30% lower (3.37±0.35%Δ) than in their peers with NFG and 58% lower than young controls (P&lt;0.05). Brachial artery FMD was greater (6.38±0.35%Δ) in MA/O adults with NFG who regularly performed aerobic exercise (&gt;45 min/day for ≥5 days/week, 62±1 years, n=23) compared with their non-exercising peers and only slightly less than young controls (P&lt;0.05). Most importantly, FMD was completely preserved in MA/O adults with IFG who regularly performed aerobic exercise (6.99±0.69%Δ, 65±1 years, n=16). In the pooled sample, fasting plasma glucose was inversely related to FMD (r=−0.42, P&lt;0.01) and was the strongest independent predictor of FMD (R2=0.32). Group differences in FMD were not affected by other subject characteristics or brachial artery properties, including brachial artery dilation to sublingual NTG (nitroglycerine, i.e. endothelium-independent dilation). IFG exacerbates age-associated vascular endothelial dysfunction and this adverse effect is completely prevented in MA/O adults who regularly perform aerobic exercise.
Counselling young people: Counsellors' perspectives on ‘what works’ – An exploratory study
Authors: Westergaard Jane 
Published: October 2012

AbstractAim: Counsellors who work with young people in a range of contexts know that they are not engaging with ‘mini‐adults’. The issues young people bring to counselling are often complex, challenging and wide‐ranging, as adolescents are experiencing times of turbulence and change in their physical, emotional, social and psychological development. This paper focuses on a research project undertaken with five counsellors who work with young people, and asks the question: ‘What works?’ Method: The research project is an in‐depth qualitative study into the counsellor's experience of counselling young people, using a narrative approach. Findings: Four key shared themes emerged: the significance of ‘safety’ in the relationship; building the therapeutic alliance; flexibility and integration relating to theoretical orientation; and the use of creativity. Outcomes: This paper offers counsellors the opportunity to reflect on ‘what works’ and consider the professional knowledge, which underpins their own counselling practice with young people.
Plasmonics: visit the past to know the future
Authors: Hayashi Shinji , Okamoto Takayuki 
Published: October 2012

Abstract
Surface plasmons are collective oscillations of free electrons localized at surfaces of structures made of metals. Since the surface plasmons induce fluctuations of electric charge at surfaces, they are accompanied by electromagnetic oscillations. Electromagnetic fields associated with surface plasmons are localized at surfaces of metallic structures and significantly enhanced compared with the excitation field. These two characteristics are ingredients for making good use of surface plasmons in plasmonics. Plasmonics is a rapidly growing and well-established research field, which covers various aspects of surface plasmons towards realization of a variety of surface-plasmon-based devices. In this paper, after summarizing the fundamental aspects of surface plasmons propagating on planar metallic surfaces and localized at metallic nanoparticles, recent progress in plasmonic waveguides, plasmonic light-emitting devices and plasmonic solar cells is reviewed.
Off-diagonal particle and toroidal momentum transport: a survey of experimental, theoretical and modelling aspects
Authors: Angioni C. , Camenen Y. , Casson F.J. , Fable E. , McDermott R.M. , Peeters A.G. , Rice J.E. 
Published: October 2012

Abstract
In tokamaks, turbulent particle and toroidal momentum transport are both characterized by the presence of off-diagonal contributions which play an essential role in establishing the profile shapes of the density and the toroidal rotation under most conditions. In this paper similarities and differences between the two turbulent transport channels are pointed out and, thereby, interesting physical aspects which connect the two channels are identified. The main contributions to off-diagonal particle and toroidal momentum transport are reviewed by means of a rather simplified description, which aims at providing, when possible, a direct connection between theoretical, modelling and experimental research.
Characterization of broadband MHD fluctuations during type-II edge localized modes as measured in 2D with ECE-imaging at ASDEX Upgrade
Authors: Boom J.E. , Wolfrum E. , Classen I.G.J. , de Vries P.C. , Maraschek M. , Suttrop W. , von Thun C.P. Pérez , Donné A.J.H. , Tobias B.J. , Domier C.W. , Luhmann N.C. , Park H.K. 
Published: October 2012

Abstract
The characterization of a broadband fluctuation that is typical for the type-II ELM regime at ASDEX Upgrade has been improved using the 2D capabilities of ECE-imaging. During the transition from the type-I to type-II ELMy phase, it has been found that electron temperature fluctuations form a broadband peak in the 19–65 kHz range. In the type-II phase, this broadband fluctuation reaches a maximum relative amplitude of almost 20% just inside the top of the pedestal. Simultaneously, the electron temperature profile is completely flattened at this location. The 2D distribution of the amplitude of this broadband fluctuation is such that, when averaged over time, a minimum occurs around the mid-plane. From the measurements of the nearby magnetic pickup coils, a similar broadband fluctuation seems visible in the same frequency range. However, this is peaked at a slightly lower frequency and does not show a similar minimum. From the analysis of the fluctuations on small timescales, the poloidal and toroidal mode numbers are estimated to be m ∼ 100 and n ∼ 21. Furthermore, activity reminiscent of beat waves has been observed, which might partially account for the fluctuation's broadband nature and the seeming velocity variation of single fluctuation passages. Overall, similarities between the characteristics of this broadband fluctuation and various precursors to type-I ELMs suggest that this fluctuation can play an important role in regulating the ELM cycle.
Magnetohydrodynamic simulations of edge poloidal flows
Authors: Guazzotto L. , Betti R. 
Published: October 2012

Abstract
Edge poloidal flows exceeding the poloidal sound speed lead to the formation of a pedestal structure (Guazzotto and Betti 2011 Phys. Rev. Lett.
107 125002). This result is based on the existence of ‘transonic’ equilibria, in which the edge region of the plasma flows supersonically with respect to the poloidal sound speed (i.e. the sound speed reduced by a factor B

θ
/B), while the plasma core is rotating with subsonic poloidal velocities. The ideal-MHD equilibrium force balance shows that radial discontinuities must be present at equilibrium in the presence of transonic flows. The formation of the transonic discontinuity was proven with time-dependent simulations. In this work, we prove that the transonic discontinuity can be formed with poloidal velocities no larger than a few tens of km s−1. Such relatively slow velocities are supersonic at the bottom of the pedestal where the temperature is a few tens of eVs. We also show how realistic toroidal velocity profiles can be obtained in transonic equilibria if the appropriate choice is made for the input free functions.
Features of spontaneous and pellet-induced ELMs on the HL-2A tokamak
Authors: Huang Y. , Liu C.H. , Nie L. , Feng Z. , Ji X.Q. , Yao K. , Zhu G.L. , Liu Yi , Cui Z.Y. , Yan L.W. , Wang Q.M. , Yang Q.W. , Ding X.T. , Dong J.Q. , Duan X.R. 
Published: October 2012

Abstract
The pellet pacing ELM mitigation concept is being tested in some tokamaks such as ASDEX Upgrade, DIII-D and JET. By increasing the ELM frequency, the ELM size can be reduced and eventually suppressed to meet the lifetime requirements on ITER target plates. In the HL-2A tokamak, ELMy H-mode operation is routinely performed and small type-III ELMs with a high repetition rate and some type-I (or possibly large type-III) ELM events are observed. Large ELMs are often preceded by strong coherent magnetic oscillations, and produce obvious perturbations on plasma current I

p
, electron density

at the edge, stored energy W
E, etc. The coherent magnetic oscillations before an ELM crash or during the ELM are measured by toroidal and poloidal Mirnov coils and analysed by the wavelet technique to study the spectral characteristics of the short time ELM events. Pellet injection experiments are performed in type-III ELMy H-mode plasmas and ELM-free H-mode plasmas to study the physics of pellet triggering ELM. The analyses of pellet-induced ELMs and spontaneous ELMs are presented. Because the pellet size is relatively large, it induces magnetic oscillations lasting longer than that of a natural ELM.
ELM control experiments in the KSTAR device
Authors: Kim Jayhyun , Jeon Y.-M. , Xiao W.W. , Yoon S.-W. , Park J.-K. , Yun G.S. , Ahn J.-W. , Kim H.S. , Yang H.-L. , Kim H.K. , Park S. , Jeong J.H. , Jung M. , Choe G.H. , Ko W.H. , Lee S.-G. , Nam Y.U. , Bak J.G. , Lee K.D. , Na H.K. , Hahn S.-H. , Diamond P.H. , Rhee T. , Kwon J.M. , Sabbagh S.A. , Park Y.S. , Park H.K. , Na Y.S. , Kim W.C. , Kwak J.G. 
Published: October 2012

Abstract
The fourth KSTAR campaign in 2011 concentrated on active edge-localized mode (ELM) control by various methods such as non-axisymmetric magnetic perturbations, supersonic molecular beam injection (SMBI), vertical jogs of the plasma column and edge electron heating. The segmented in-vessel control coil (IVCC) system is capable of applying n ⩽ 2 perturbed field with different phasing among top, middle and bottom coils. Application of an n = 1 perturbed field showed a desirable ELM suppression result. Fast vertical jogs of the plasma column achieved ELM pace-making and ELMs locked to 50 Hz vertical jogs were observed with a high probability of phase locking. A newly installed SMBI system was used for ELM control and the state of mitigated ELMs was sustained by the optimized repetitive SMBI pulse for a few tens of ELM periods. A change in ELM behaviour was seen due to edge electron heating although the effect of ECH launch needs supplementary analyses. The ECEI images of suppressed/mitigated ELM states showed apparent differences when compared with natural ELMy states. Further analyses are ongoing to explain the observed ELM control results.
Temporally resolved analysis of the response of density and temperature to modulated central electron heating on ASDEX Upgrade
Authors: Mlynek A. , Angioni C. , Fable E. , Fischer R. , Ryter F. , Stober J. , Suttrop W. , Zohm H. 
Published: October 2012

Abstract
In recent years, it has been found that the application of local heat sources in a fusion plasma can influence the shape of the density profile. This shows that a coupling between heat and particle transport exists, which is taken into account in transport models by introducing off-diagonal transport coefficients. In existing studies, the focus of analysis is mostly on the density profile that occurs after a sufficiently long settling time after altering the heating power level. In this paper, the transient behaviour of temperature and density in response to steps in the applied heating power is analysed, which leads to the observation of hysteresis loops in the local density–temperature diagram. Based on numerical transport simulations, it is shown that the occurrence of hysteresis curves can be reproduced on the basis of today's physics understanding, where the shape of the curve provides additional information on the transport coefficients and their interdependences.
Effects of local toroidal field ripples due to test blanket modules for ITER on radial transport of thermal ions
Authors: Oyama N. , Urano H. , Shinohara K. , Honda M. , Takizuka T. , Hayashi N. , Kamada Y. 
Published: October 2012

Abstract
The effects of local toroidal field (TF) ripples due to ferromagnetic steels used in test blanket modules (TBMs) in ITER on the radial transport of thermal ions located near the top of the pedestal are investigated using a fully three-dimensional magnetic field orbit following Monte Carlo (F3D-OFMC) code. In the simulation, the three-dimensional motion of 20 000 test particles, distributed near the top of the pedestal (Ψ
N
= 0.91) with the same Maxwellian velocity distribution as the thermal ions at this location, is traced for 1.9 s. In comparison with the number of lost particles in the case without a TBM, the additional loss with three TBM ports expected in ITER is evaluated to be less than 1% of the test particles. The additional losses increase linearly with the number of TBM ports and with the square of the amplitude of the local TF ripple. The poloidal structure of the TF ripple without ferritic inserts and a case with 18 TBM ports are also compared. It is found that cases having the same ripple amplitude at a certain point can have substantially different additional loss rates if the poloidal ripple structure is not the same. The ripple amplitude near the banana tip seems to be the most important factor in determining the radial diffusion of thermal ions.
L–H transition in the presence of magnetic perturbations in ASDEX Upgrade
Authors: Ryter F. , Rathgeber S.K. , Viezzer E. , Suttrop W. , Burckhart A. , Fischer R. , Kurzan B. , Potzel S. , Pütterich T. 
Published: October 2012

Abstract
The L–H transition and the H-mode behaviour in the presence of non-axisymmetric n = 2 magnetic perturbations have been investigated. At low density no effect on the L–H transition is observed. Within a rather narrow density window around 50% of the Greenwald density limit, a transition to H-mode with small ELMs only and good confinement can be achieved. However, a strong density dependence of the L–H threshold power in the presence of magnetic perturbations forces the plasmas to remain in L-mode when the density is above 60% of the Greenwald value. The H-mode confinement time is not affected by the presence of the magnetic perturbations. All of these H-modes, with and without ELM mitigation, exhibit a common confinement degradation with increasing recycling.
Particle transport in density gradient driven TE mode turbulence
Authors: Skyman A. , Nordman H. , Strand P.I. 
Published: October 2012

Abstract
The turbulent transport of main ion and trace impurities in a tokamak device in the presence of steep electron density gradients has been studied. The parameters are chosen for trapped electron mode turbulence, driven primarily by steep electron density gradients relevant to H-mode physics. Results obtained through nonlinear and quasilinear gyrokinetic simulations using the GENE code are compared with results obtained from a fluid model. Impurity transport is studied by examining the balance of convective and diffusive transport, as quantified by the density gradient corresponding to zero particle flux (impurity peaking factor). Scalings are obtained for the impurity peaking with the background electron density gradient and the impurity charge number. It is shown that the impurity peaking factor is weakly dependent on impurity charge and significantly smaller than the driving electron density gradient.
H-mode characterization for dominant ECRH and comparison to dominant NBI and ICRF heating at ASDEX Upgrade
Authors: Sommer F. , Stober J. , Angioni C. , Bernert M. , Burckhart A. , Bobkov V. , Fischer R. , Fuchs C. , McDermott R.M. , Suttrop W. , Viezzer E. 
Published: October 2012

Abstract
The influence of pure electron heating versus combined electron and ion heating on a high collisionality H-mode plasma has been investigated in ASDEX Upgrade. This was done by replacing both neutral beam injection (NBI) and ion cyclotron resonance frequency (ICRF) heating in small steps with electron cyclotron resonance heating (ECRH) while keeping the total heating power constant. The stability of the global plasma parameters and the response of the kinetic profiles on the changed heating mix and torque input is shown. The differences in edge localized mode behaviour between the different heating mixes is reported. The data were analysed with an interpretative transport model and linear gyrokinetic simulations were performed to evaluate the underlying transport mechanism.
A model for the reversal of the toroidal rotation in tokamak
Authors: Spineanu Florin , Vlad Madalina 
Published: October 2012

Abstract
The transition from toroidal counter- to co-rotation in the core plasma has been observed at L to H transition in several tokamaks. Spontaneous reversal has also been observed in TCV beyond a threshold in the density. We develop a model based on the following phenomenology: (1) the increase in the gradient of the pressure triggers formation on a fast time scale of cells of convection (similar to Rayleigh–Benard, but with a single sign of vorticity); (2) poloidal rotation is induced by the envelope of the peripheric velocity of the convection cells; via the baroclinic term the gradients of temperature and density sustain the poloidal rotation against the decay due to the parallel viscosity; (3) the fast increase in poloidal flow induces a high-time derivative of the radial electric field; (4) the neoclassical polarization creates a series of parallel accelerations (kicks on each bounce) of the trapped ions, leading to an increase in the toroidal precession or to its reversal; the source of energy is the work done by the radial electric field. (5) the diffusion transfers on resistive scale the toroidal momentum from the trapped ions to the untrapped ones. The correlated interactions are examined and the estimated time scales are found to be compatible with the observations.
H-mode access by pellet fuelling in the MAST tokamak
Authors: Valovič M. , Garzotti L. , Gurl C. , Akers R. , Harrison J. , Michael C. , Naylor G. , Scannell R. 
Published: October 2012

Abstract
Access into H-mode is studied in the MAST tokamak when plasma is fuelled by cryogenic pellets. It is shown that pellet fuelling from the high-field side allows access to H-mode in plasmas heated by neutral beams. Simple and two-stage L–H transitions are identified. The results of comparison of the L–H transitions with pellet injection with transitions where plasmas are fuelled solely by gas puffing depend on the gas puff geometry: fuelling by high-field side gas leads to an L–H transition at the density comparable to the transition with pellet injection. In contrast low-field gas can completely prevent the L–H transition.
Magnetohydrodynamic tokamak plasma edge stability
Authors: Webster Anthony J. 
Published: October 2012

Abstract
The edge of a tokamak plasma is interesting due to its geometrical structure that is difficult to model mathematically and computationally, its tendency to form ‘transport barriers’ with increased confinement of energy and momentum, and the edge-localized instabilities associated with transport barriers that threaten the lifetime of components in large tokamaks. Ideal magnetohydrodynamics (MHD) is generally well understood, but only in the past decade has a good theoretical understanding emerged of MHD stability near the plasmas' separatrix when one or more X-points are present. By reviewing and discussing our theoretical understanding of ideal MHD stability of the plasma's edge, a clear picture emerges for its ideal stability. Conclusions are: ideal MHD will limit the width of strong transport barriers at the plasma's edge, a strong edge transport barrier will be associated with ELMs, ELMs will have a maximum toroidal mode number, will be preceded by smaller precursor instabilities, and can be triggered by sufficient changes to either the edge or the core plasma. Observations are made for the mechanisms responsible for edge transport barriers and ELMs, some leading to experimental predictions, others highlighting important open questions.
Ubiquity of non-diffusive momentum transport in JET H-modes
Authors: Weisen H. , Camenen Y. , Salmi A. , Versloot T.W. , deVries P.C. , Maslov M. , Tala T. , Beurskens M. , Giroud C. 
Published: October 2012

Abstract
A broad survey of the experimental database of neutral beam heated baseline H-modes and hybrid scenarios in the JET tokamak has established the ubiquity of non-diffusive momentum transport mechanisms in rotating plasmas. As a result of their presence, the normalized angular frequency gradient R∇ω/ω is higher than expected from momentum diffusion alone, by about unity in the core (r/a ∼ 0.3), rising to near 5 close to the edge, where its contribution to the total gradient is comparable to the gradient associated with the diffusive flux. The magnitude and parameter dependences of the non-diffusive contribution to the gradient are consistent with a theoretically expected pinch, which has its origin in the vertical particle drift resulting from the Coriolis force. Linear gyrokinetic calculations of the pinch number RV/χ

φ
and the Prandtl number χ

φ
/χ
i are in good agreement with the experimental observations, with similar dependences on R/L

n
, q and ε = r/R. A contribution due to residual stresses may also be present, but could not be identified with certainty.