143 research outputs found
2D continuous spectrum of shear Alfven waves in the presence of a magnetic island
The radial structure of the continuous spectrum of shear Alfven modes is
calculated in the presence of a magnetic island in tokamak plasmas. Modes with
the same helicity of the magnetic island are considered in a slab model
approximation. In this framework, with an appropriate rotation of the
coordinates the problem reduces to 2 dimensions. Geometrical effects due to the
shape of the flux surface's cross section are retained to all orders. On the
other hand, we keep only curvature effects responsible of the beta induced gap
in the low-frequency part of the continuous spectrum. New continuum
accumulation points are found at the O-point of the magnetic island. The
beta-induced Alfven Eigenmodes (BAE) continuum accumulation point is found to
be positioned at the separatrix flux surface. The most remarkable result is the
nonlinear modification of the BAE continuum accumulation point frequency
IDENTIFICATION OF A MULTIDRUG AND TOXIC EXTRUSION TRANSPORTER INVOLVED IN THE SECRETION OF INDOLE-3-ACETIC ACID AND ITS CONJUGATES IN PSEUDOMONAS SAVASTANOI.
NEXT GENERATION ECOFRIENDLY CONTROL OF GRAM NEGATIVE PLANT PATHOGENIC BACTERIA: VIRULENCE INHIBITING PEPTIDES AND POLYPHENOLS FROM NO-FOOD PLANT BIOMASS
A 3D-Shape Similarity-based Contrastive Approach to Molecular Representation Learning
Molecular shape and geometry dictate key biophysical recognition processes,
yet many graph neural networks disregard 3D information for molecular property
prediction. Here, we propose a new contrastive-learning procedure for graph
neural networks, Molecular Contrastive Learning from Shape Similarity
(MolCLaSS), that implicitly learns a three-dimensional representation. Rather
than directly encoding or targeting three-dimensional poses, MolCLaSS matches a
similarity objective based on Gaussian overlays to learn a meaningful
representation of molecular shape. We demonstrate how this framework naturally
captures key aspects of three-dimensionality that two-dimensional
representations cannot and provides an inductive framework for scaffold
hopping
Interaction of Alfvénic modes and turbulence via the nonlinear modification of the equilibrium profiles
ORB5: a global electromagnetic gyrokinetic code using the PIC approach in toroidal geometry
This paper presents the current state of the global gyrokinetic code ORB5 as
an update of the previous reference [Jolliet et al., Comp. Phys. Commun. 177
409 (2007)]. The ORB5 code solves the electromagnetic Vlasov-Maxwell system of
equations using a PIC scheme and also includes collisions and strong flows. The
code assumes multiple gyrokinetic ion species at all wavelengths for the
polarization density and drift-kinetic electrons. Variants of the physical
model can be selected for electrons such as assuming an adiabatic response or a
``hybrid'' model in which passing electrons are assumed adiabatic and trapped
electrons are drift-kinetic. A Fourier filter as well as various control
variates and noise reduction techniques enable simulations with good
signal-to-noise ratios at a limited numerical cost. They are completed with
different momentum and zonal flow-conserving heat sources allowing for
temperature-gradient and flux-driven simulations. The code, which runs on both
CPUs and GPUs, is well benchmarked against other similar codes and analytical
predictions, and shows good scalability up to thousands of nodes
Global electromagnetic gyrokinetic simulations of Energetic Particle driven instabilities in ITER
Students’ Confidence and Interest in Palliative and Bereavement Care: A European Study
As part of a European Erasmus Plus project entitled Death Education for Palliative Psychology, this study assessed the ways in which Master’s Degree students in psychology and the creative arts therapies self-rated their confidence and interest in death education and palliative and bereavement care. In five countries (Austria, Israel, Italy, Poland, Romania), 344 students completed an online questionnaire, and 37 students were interviewed to better understand their views, interest, and confidence. The results revealed some significant differences between countries, and showed that older respondents with previous experience as formal caregivers for end-of-life clients showed greater interest in obtaining practical clinical competence in these fields. A mediation analysis indicated that students’ previous care experiences and past loss experiences were related to students’ current interest in death education and palliative and bereavement care through the mediation of their sense of confidence in this field. The qualitative findings identified five shared themes: life and death, learning about death, the psychological burden, personal experience and robust training, and four key training needs. Overall, students’ interest in studying and working with terminal illness and death are rooted in internal resources, a preliminary sense of confidence, but also external requirements
Nonlinear interaction of Alfv\'enic instabilities and turbulence via the modification of the equilibrium profiles
Nonlinear simulations of Alfv\'en modes (AM) driven by energetic particles
(EP) in the presence of turbulence are performed with the gyrokinetic
particle-in-cell code ORB5. The AMs carry a heat flux, and consequently they
nonlinearly modify the plasma temperature profiles. The isolated effect of this
modification on the dynamics of turbulence is studied, by means of
electrostatic simulations. We find that turbulence is reduced when the profiles
relaxed by the AM are used, with respect to the simulation where the
unperturbed profiles are used. This is an example of indirect interaction of
EPs and turbulence. First, an analytic magnetic equilibrium with circular
concentric flux surfaces is considered as a simplified example for this study.
Then, an application to an experimentally relevant case of ASDEX Upgrade is
discussed
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