Chiral Magnetic Effect in the Dirac-Heisenberg-Wigner formalism

In this paper the emergence of the Chiral Magnetic Effect (CME) and the related anomalous current is investigated using the real time Dirac-Heisenberg-Wigner formalism. This method is widely used for describing strong field physics and QED vacuum tunneling phenomena as well as pair production in heavy-ion collisions. We extend earlier investigations of the CME in constant flux tube configuration by considering time dependent fields. In this model we can follow the formation of axial charge separation, formation of axial current and then the emergence of the anomalous electric current. Qualitative results are shown for special field configurations that help to interpret the predictions of CME related effects in heavy-ion collisions at the RHIC Beam Energy Scan program.Comment: 5 pages, 5 figure

Simulation of Pair Production in Extreme Strong EM Fields

In this article we review a theoretical framework for pair production from strong external electromagnetic fields. We propose a numerical method to solve the resulting equations of motion and present results for both cases of spatially homogeneous and inhomogeneous electric fields.Comment: 5 pages, 2 figure

The role of weakest links and system size scaling in multiscale modeling of stochastic plasticity

Plastic deformation of crystalline and amorphous matter often involves intermittent local strain burst events. To understand the physical background of the phenomenon a minimal stochastic mesoscopic model was introduced, where microstructural details are represented by a fluctuating local yielding threshold. In the present paper, we propose a method for determining this yield stress distribution by lower scale discrete dislocation dynamics simulations and using a weakest link argument. The success of scale-linking is demonstrated on the stress-strain curves obtained by the resulting mesoscopic and the discrete dislocation models. As shown by various scaling relations they are statistically equivalent and behave identically in the thermodynamic limit. The proposed technique is expected to be applicable for different microstructures and amorphous materials, too.Comment: 13 pages, 12 figure

Az akut L-kinurenin szulfát kezelés magatartási, szövettani és keringési hatásainak komplex vizsgálata C57Bl/6j egér törzsben

L-Kynurenine (L-KYN) is a central metabolite of tryptophan degradation: known as kynurenine pathway, it is a cascade of enzymatic steps generating biologically active compounds, through which more than 95% of the tryptophan is catabolized. The early phase of the catabolic steps takes place mainly in the liver and the kidneys. However, the metabolization of L-KYN can effectively proceeds in the brain. The blood brain barrier strongly limits the penetrability of the kynurenine metabolites from the periphery to the central nervous system, since most of them can only be transferred by passive diffusion with a very low efficacy. One clear exception is the L-KYN, which can enter the brain with the aid of a large neutral amino acid transporter. Thus, the cerebral kynurenine metabolism is very responsive to the peripheral level of the L-KYN. Preclinical studies have shown that growth in the level of systemic L-KYN is particularly associated with a dose-dependent increase of its direct downstream metabolite kynurenic acid (KYNA) in the central nervous system. Evidence suggests that in the physiologically intact brain the most prominent and rapid change after peripheral L-KYN administration is the peak elevation of KYNA. KYNA is a complex neuromodulator, antioxidant and neuroprotective endogenous molecule. Elevation of brain KYNA content is correlated with attenuation in the concentration of extracellular glutamate, dopamine and acetylcholine in distinct cortical and subcortical brain regions. KYNA influences neurotransmission through multiple actions at the pre- and postsynaptic site. KYNA directly attenuates neurotransmitter release, partly by inhibiting α7 nicotinic acetylcholine (α7nACh) receptor located on presynaptic terminals, and partly by stimulating G-protein-coupled receptor 35 (GPR35) localized on neurons and astrocytes. Thus, even the modest fluctuations in endogenous KYNA can bi-directionally control the extracellular levels of glutamate. KYNA hinders postsynaptic N-methyl-D-aspartate (NMDA) receptor currents by competitive antagonism at allosteric glycine binding site of NMDA receptor. Moreover, in the periphery and in the brain during neuroinflammation, KYNA promotes anti-inflammatory responses due to activation of aryl hydrocarbon receptor and GPR35 receptor expressed by immune-cells, as well as it presumably also modulates neuronal survival through extrasynaptic NMDA receptor blockade. Besides its receptor-mediated actions, KYNA itself is a potent antioxidant. Therefore, elevation of brain KYNA level, either by administration of L-KYN or pharmacological manipulation of the availability of the kynurenine pathway enzymes, has become an attractive strategy to attenuate neuroinflammatory responses and to protect against glutamate induced excitotoxicity associated with ischemic brain injury. Accordingly, we and our collaborators achieved neuroprotection by the administration of L-KYN sulfate (L-KYNs) in experimental models of neurodegenerative diseases and ischemic stroke. Decades after the discovery of the neurotoxic and convulsant properties of glutamate, it has become clear that glutamate hypofunction is also pathogenic and therefore undesirable. Accordingly, in preclinical studies acute or chronic elevation of brain KYNA content, achieved partly by the peripheral administration of L-KYN, has been suggested to trigger alteration in the behavior of rodents: animals expressed hypoactivity or spatial working memory deficit. Moreover, pre- and postnatal chronic L-KYN exposure provoked long-lasting neurochemical and behavioral abnormalities manifested in adulthood. However, the results assessing the behavioral effects of the kynurenerg manipulations emerged from studies that focused mainly on rats, after various-dose of L-KYNs treatment. Implementing similar experiments in mice is of particular importance, because such data is almost absent from the literature. Additionally, the available information concerning the effects of kynurenerg manipulation beyond neuroprotection is quite incomplete, since study on dose-dependent responses to various L-KYNs treatment is not available. On a top of these, L-KYN and KYNA were attributed a direct role in the regulation of the systemic circulation. Namely, L-KYN was identified as an endothelium-derived vasodilator, contributing to peripheral arterial relaxation and regulation of blood pressure during systemic inflammation in rats. Furthermore, intravenous administration of low-dose L-KYN (1 mg/kg) has been shown to increase cerebral blood flow (CBF) in conscious rabbits. Therefore, we hypothesized that acute elevation of systemic L-KYN concentration may exert potential effects on mean arterial blood pressure (MABP) and on resting CBF in the adult mouse brain..

Remembering and Forgetting: Lizkor VeLishkoach for String Quartet, after Schubert

Lizkor VeLishkoach (to Remember and to Forget) is a piece that is to be played together with Franz Schubert’s Quartet in G Major D887. Lizkor VeLishkoach (hebrew for “to remember and to forget”) forms its meaning from the roots of the words of its title. The root of “lizkor” is “zekher”, which means both “memory” and “imprint.” Embedded within the verb “lishkoakh” is the word “koakh” meaning “power.” In this paper, I explore aspects of time, memory and place within my quartet, aspects that have become “imprinted” within a personal subjective and larger collective memory. Investigating my own reaction to Schubert’s quartet, I examine how its form and material is re-collected within my own composition. Retracing the re-membering of Schubert’s quartet, I also speculate about my own re-membering and forgetting within the context of this chosen form.Lizkor VeLishkoach est une pièce qui est conçue pour être au même programme que le Quatuor en sol majeur D887 de Franz Schubert. Lizkor VeLishkoach (qui signifie « Se souvenir et oublier » en hébreu) trouve tout son sens dans la racine des mots qui forment son titre. La racine de « lizkor » est « zekher », qui singnifie à la fois « mémoire » et « impression ». Le verbe « lishkoakh » contient le mot « koakh », qui singifie « pouvoir ». Dans cet article, l’auteur explore des aspects du temps, de la mémoire et du lieu auquels se rattache son quatuor, des aspects qui sont « imprimés » dans sa propre mémoire subjective, mais aussi dans une plus vaste mémoire collective. Analysant sa propre perception du quatuor de Schubert, il vérifie à quel point sa forme et son matériau sont réappropriés dans son oeuvre à lui. Retraçant les rappels au quatuor de Schubert, il spécule sur ses propres souvenirs et oublis dans le contexte de la forme choisie

The Practice of Teaching Composition

In this essay, composer Dániel Péter Biró reveals his methodology and trajectory as a professor of music composition in the last 16 years. Biró explains how can one teaches a creative artistic process nowadays, in a globalized musical culture, which is full of possibilities for development of cultural diversity while simultaneously providing students distractions driven by capitalist paradigms. How can one help each student to develop his/her own musical language? For this task, Biró talks about how composition today is creative process highly grounded in intellectual and interdisciplinary approaches, sharing similarities with other areas of research such as philosophy and history. For this task, the composer relies on musical analysis in his seminars and individual lessons as one of the strongest methodologies to learn composition, alongside integrating music technology and contemporary performance practice research. [note by editor]

The Practice of Teaching Composition

In this essay, composer Dániel Péter Biró reveals his methodology and trajectory as a professor of music composition in the last 16 years. Biró explains how can one teaches a creative artistic process nowadays, in a globalized musical culture, which is full of possibilities for development of cultural diversity while simultaneously providing students distractions driven by capitalist paradigms. How can one help each student to develop his/her own musical language? For this task, Biró talks about how composition today is creative process highly grounded in intellectual and interdisciplinary approaches, sharing similarities with other areas of research such as philosophy and history. For this task, the composer relies on musical analysis in his seminars and individual lessons as one of the strongest methodologies to learn composition, alongside integrating music technology and contemporary performance practice research. [note by editor]