A multi-machine scaling of halo current rotation

Halo currents generated during unmitigated tokamak disruptions are known to develop rotating asymmetric features that are of great concern to ITER because they can dynamically amplify the mechanical stresses on the machine. This paper presents a multi-machine analysis of these phenomena. More specifically, data from C-Mod, NSTX, ASDEX Upgrade, DIII-D, and JET are used to develop empirical scalings of three key quantities: (1) the machinespecific minimum current quench time, τCQ; (2) the halo current rotation duration, trot; and (3) the average halo current rotation frequency, fh . These data reveal that the normalized rotation duration, trot/τCQ, and the average rotation velocity, vh , are surprisingly consistent from machine to machine. Furthermore, comparisons between carbon and metal wall machines show that metal walls have minimal impact on the behavior of rotating halo currents. Finally, upon projecting to ITER, the empirical scalings indicate that substantial halo current rotation above fh = 20 Hz is to be expected. More importantly, depending on the projected value of τCQ in ITER, substantial rotation could also occur in the resonant frequency range of 6–20 Hz. As such, the possibility of damaging halo current rotation during unmitigated disruptions in ITER cannot be ruled out.EURATOM 633053RCUK Energy Programme EP/ I501045Princeton University DE-AC02-09CH1146

An improved set of electron-THFA cross sections refined through a neural network-based analysis of swarm data

We review experimental and theoretical cross sections for electron transport in α-tetrahydrofurfuryl alcohol (THFA) and, in doing so, propose a plausible complete set. To assess the accuracy and self-consistency of our proposed set, we use the pulsed-Townsend technique to measure drift velocities, longitudinal diffusion coefficients, and effective Townsend first ionization coefficients for electron swarms in admixtures of THFA in argon, across a range of density-reduced electric fields from 1 to 450 Td. These measurements are then compared to simulated values derived from our proposed set using a multi-term solution of Boltzmann’s equation. We observe discrepancies between the simulation and experiment, which we attempt to address by employing a neural network model that is trained to solve the inverse swarm problem of unfolding the cross sections underpinning our experimental swarm measurements. What results from our neural network-based analysis is a refined set of electron-THFA cross sections, which we confirm is of higher consistency with our swarm measurements than that which we initially proposed. We also use our database to calculate electron transport coefficients in pure THFA across a range of reduced electric fields from 0.001 to 10000 Td

Donor Centers and Absorption Spectra in Quantum Dots

We have studied the electronic properties and optical absorption spectra of three different cases of donor centers, D^{0}, D^{-} and D^{2-}, which are subjected to a perpendicular magnetic field, using the exact diagonalization method. The energies of the lowest lying states are obtained as function of the applied magnetic field strength B and the distance zeta between the positive ion and the confinement xy-plane. Our calculations indicate that the positive ion induces transitions in the ground-state, which can be observed clearly in the absorption spectra, but as zeta goes to 0 the strength of the applied magnetic field needed for a transition to occur tends to infinity.Comment: 5 pages, 4 figures, REVTeX 4, gzipped tar fil

Evaluation of the anti-diabetic activity of some common herbs and spices : providing new insights with inverse virtual screening

Culinary herbs and spices are widely used as a traditional medicine in the treatment of diabetes and its complications, and there are several scientific studies in the literature supporting the use of these medicinal plants. However, there is often a lack of knowledge on the bioactive compounds of these herbs and spices and their mechanisms of action. The aim of this study was to use inverse virtual screening to provide insights into the bioactive compounds of common herbs and spices, and their potential molecular mechanisms of action in the treatment of diabetes. In this study, a library of over 2300 compounds derived from 30 common herbs and spices were screened in silico with the DIA-DB web server against 18 known diabetes drug targets. Over 900 compounds from the herbs and spices library were observed to have potential anti-diabetic activity and liquorice, hops, fennel, rosemary, and fenugreek were observed to be particularly enriched with potential anti-diabetic compounds. A large percentage of the compounds were observed to be potential polypharmacological agents regulating three or more anti-diabetic drug targets and included compounds such as achillin B from yarrow, asparasaponin I from fenugreek, bisdemethoxycurcumin from turmeric, carlinoside from lemongrass, cinnamtannin B1 from cinnamon, crocin from sa ron and glabridin from liquorice. The major targets identified for the herbs and spices compounds were dipeptidyl peptidase-4 (DPP4), intestinal maltase-glucoamylase (MGAM), liver receptor homolog-1 (NR5A2), pancreatic alpha-amylase (AM2A), peroxisome proliferator-activated receptor alpha (PPARA), protein tyrosine phosphatase non-receptor type 9 (PTPN9), and retinol binding protein-4 (RBP4) with over 250 compounds observed to be potential inhibitors of these particular protein targets. Only bay leaves, liquorice and thyme were found to contain compounds that could potentially regulate all 18 protein targets followed by black pepper, cumin, dill, hops and marjoram with 17 protein targets. In most cases more than one compound within a given plant could potentially regulate a particular protein target. It was observed that through this multi-compound-multi target regulation of these specific protein targets that the major anti-diabetic e ects of reduced hyperglycemia and hyperlipidemia of the herbs and spices could be explained. The results of this study, taken together with the known scientific literature, indicated that the anti-diabetic potential of common culinary herbs and spices was the result of the collective action of more than one bioactive compound regulating and restoring several dysregulated and interconnected diabetic biological processes.The National Research Foundation of South Africa, the Spanish Ministry of Economy and Competitiveness (CTQ2017-87974-R) and by the Fundación Séneca del Centro de Coordinación de la Investigación de la Región de Murcia under Project 20988/PI/18.http://www.mdpi.com/journal/moleculesam2020BiochemistryGeneticsMicrobiology and Plant Patholog

Application of seminal plasma in sex-sorting and sperm cryopreservation

Substantial dilution of boar semen during processing decreased the concentration of seminal plasma, perhaps contributing to the decline in sperm quality after cryopreservation and sex-sorting. Results of replacing seminal plasma in investigations from many laboratories have been contradictory. Results and discussion here suggest that whereas membrane status can be influenced by seminal plasma, the action of its various components, both positive and negative, is determined in part by the membrane status of the spermatozoa to which it is being exposed. Although progress has been made in identifying components of seminal plasma responsible for its protective effect (notably PSP-I/II spermadhesin for sex-sorted boar spermatozoa), little is known (in any species) regarding how external factors may influence their levels, and their functionality, in seminal plasma. It is noteworthy that seminal plasma is beneficial to post-thaw quality of sex-sorted ram spermatozoa only when added before freezing, not after thawing. Therefore, the action of seminal plasma and its components is dependent on sperm-related factors, in particular the type of processing to which they have been previously exposed. Further research is needed to unravel these biological complexities, and then characterise and synthesise useful proteins within seminal plasma. © 2008

Incorporating Descriptive Metadata into Seismic Source Zone Models for Seismic Hazard Assessment: A case study of the Azores-West Iberian region

In probabilistic seismic-hazard analysis (PSHA), seismic source zone (SSZ) models are widely used to account for the contribution to the hazard from earth- quakes not directly correlated with geological structures. Notwithstanding the impact of SSZ models in PSHA, the theoretical framework underlying SSZ models and the criteria used to delineate the SSZs are seldom explicitly stated and suitably docu- mented. In this paper, we propose a methodological framework to develop and docu- ment SSZ models, which includes (1) an assessment of the appropriate scale and degree of stationarity, (2) an assessment of seismicity catalog completeness-related issues, and (3) an evaluation and credibility ranking of physical criteria used to delin- eate the boundaries of the SSZs. We also emphasize the need for SSZ models to be supported by a comprehensive set of metadata documenting both the unique character- istics of each SSZ and the criteria used to delineate its boundaries. This procedure ensures that the uncertainties in the model can be properly addressed in the PSHA and that the model can be easily updated whenever new data are available. The pro- posed methodology is illustrated using the SSZ model developed for the Azores–West Iberian region in the context of the Seismic Hazard Harmonization in Europe project (project SHARE) and some of the most relevant SSZs are discussed in detail

States and transitions in black-hole binaries

With the availability of the large database of black-hole transients from the Rossi X-Ray Timing Explorer, the observed phenomenology has become very complex. The original classification of the properties of these systems in a series of static states sorted by mass accretion rate proved not to be able to encompass the new picture. I outline here a summary of the current situation and show that a coherent picture emerges when simple properties such as X-ray spectral hardness and fractional variability are considered. In particular, fast transition in the properties of the fast time variability appear to be crucial to describe the evolution of black-hole transients. Based on this picture, I present a state-classification which takes into account the observed transitions. I show that, in addition to transients systems, other black-hole binaries and Active Galactic Nuclei can be interpreted within this framework. The association between these states and the physics of the accretion flow around black holes will be possible only through modeling of the full time evolution of galactic transient systems.Comment: 30 pages, 11 figures, To appear in Belloni, T. (ed.): The Jet Paradigm - From Microquasars to Quasars, Lect. Notes Phys. 794 (2009

Influences on the triple alpha process beyond the Hoyle state

7 pags., 3 figs. -- International Symposium on Nuclear Astrophysics - Nuclei in the Cosmos - IX, 25-30 June 2006, CERNThe triple alpha process is studied using indirect methods. The beta decays of 12N and 12B are used to probe the triple alpha continuum of 12C. Different independent breakup channels are identified, consistently showing that the 10 MeV strength is dominated by a 0+ state interfering with the Hoyle state ghost. The 13–14 MeV region on the other hand is dominated by a 2 + state