Strong suppression of Coulomb corrections to the cross section of e+e- pair production in ultrarelativistic nuclear collisions

The Coulomb corrections to the cross section of $e^+e^-$ pair production in ultrarelativistic nuclear collisions are calculated in the next-to-leading approximation with respect to the parameter $L=\ln \gamma_A\gamma_B$ ($\gamma_{A,B}$ are the Lorentz factors of colliding nuclei). We found considerable reduction of the Coulomb corrections even for large $\gamma_A\gamma_B$ due to the suppression of the production of $e^+e^-$ pair with the total energy of the order of a few electron masses in the rest frame of one of the nuclei. Our result explains why the deviation from the Born result were not observed in the experiment at SPS.Comment: 4 pages, RevTe

Туризм и внешняя торговля АР Крым: географические аспекты современного развития

Целью данной статьи является оценка современного состояния внешней торговли АР Крым и ее составляющей – туристской деятельности

Growth, strain, and spin-orbit torques in epitaxial Ni-Mn-Sb films sputtered on GaAs

We report current-induced spin torques in epitaxial NiMnSb films on a commercially available epiready GaAs substrate. The NiMnSb was grown by cosputtering from three targets using optimized parameters. The films were processed into microscale bars to perform current-induced spin-torque measurements. Magnetic dynamics were excited by microwave currents, and electric voltages along the bars were measured to analyze the symmetry of the current-induced torques. We found that the extracted symmetry of the spin torques matches those expected from spin-orbit interaction in a tetragonally distorted half-Heusler crystal. Both fieldlike and dampinglike torques are observed in all the samples characterized, and the efficiency of the current-induced torques is comparable to that of ferromagnetic metal/heavy-metal bilayers

A Synthetic-Vision Based Steering Approach for Crowd Simulation

International audienceIn the everyday exercise of controlling their locomotion, humans rely on their optic flow of the perceived environment to achieve collision-free navigation. In crowds, in spite of the complexity of the environment made of numerous obstacles, humans demonstrate remarkable capacities in avoiding collisions. Cognitive science work on human locomotion states that relatively succinct information is extracted from the optic flow to achieve safe locomotion. In this paper, we explore a novel vision-based approach of collision avoidance between walkers that fits the requirements of interactive crowd simulation. By simulating humans based on cognitive science results, we detect future collisions as well as the level of danger from visual stimuli. The motor-response is twofold: a reorientation strategy prevents future collision, whereas a deceleration strategy prevents imminent collisions. Several examples of our simulation results show that the emergence of self-organized patterns of walkers is reinforced using our approach. The emergent phenomena are visually appealing. More importantly, they improve the overall efficiency of the walkers' traffic and avoid improbable locking situations

Andersen-Tawil Syndrome Presenting with Complete Heart Block

Andersen-Tawil syndrome (ATS) is a rare autosomal dominant neuromuscular disorder due to mutations in the KCNJ2 gene. The classical phenotype of ATS consists of a triad of periodic paralysis, cardiac conduction abnormalities and dysmorphic features. Episodes of either muscle weakness or cardiac arrhythmia may predominate however, and dysmorphic features may be subtle, masking the true breadth of the clinical presentation, and posing a diagnostic challenge. The severity of cardiac involvement varies but includes reports of life-threatening events or sudden cardiac death, usually attributed to ventricular tachyarrhythmias. We report the first case of advanced atrioventricular (AV) block in ATS and highlight clinical factors that may delay diagnosis

Regions of homozygosity as risk factors for multiple myeloma.

Genomic regions of homozygosity (ROH), detectable in outbred populations, have been implicated as determinants of inherited risk. To examine whether ROH is associated with risk of multiple myeloma (MM), we performed whole-genome homozygosity analysis using single-nucleotide polymorphism genotype data from 2,282 MM cases and 5,197 controls, with replication in an additional 878 MM cases and 7,083 controls. Globally, the distribution of ROH between cases and controls was not significantly different. However, one ROH at chromosome 9q21, harboring the B-cell transcription factor gene KLF9, showed evidence of a consistent association and may therefore warrant further investigation as a candidate risk factor for MM. Overall, our analysis provides little support for a homozygosity signature being a significant factor in MM risk

COVID-19 publications: Database coverage, citations, readers, tweets, news, Facebook walls, Reddit posts

© 2020 The Authors. Published by MIT Press. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1162/qss_a_00066The COVID-19 pandemic requires a fast response from researchers to help address biological, medical and public health issues to minimize its impact. In this rapidly evolving context, scholars, professionals and the public may need to quickly identify important new studies. In response, this paper assesses the coverage of scholarly databases and impact indicators during 21 March to 18 April 2020. The rapidly increasing volume of research, is particularly accessible through Dimensions, and less through Scopus, the Web of Science, and PubMed. Google Scholar’s results included many false matches. A few COVID-19 papers from the 21,395 in Dimensions were already highly cited, with substantial news and social media attention. For this topic, in contrast to previous studies, there seems to be a high degree of convergence between articles shared in the social web and citation counts, at least in the short term. In particular, articles that are extensively tweeted on the day first indexed are likely to be highly read and relatively highly cited three weeks later. Researchers needing wide scope literature searches (rather than health focused PubMed or medRxiv searches) should start with Dimensions (or Google Scholar) and can use tweet and Mendeley reader counts as indicators of likely importance

Transcription factors OVOL1 and OVOL2 induce the mesenchymal to epithelial transition in human cancer

Cell plasticity regulated by the balance between the mesenchymal to epithelial transition (MET) and the opposite program, EMT, is critical in the metastatic cascade. Several transcription factors (TFs) are known to regulate EMT, though the mechanisms of MET remain unclear. We demonstrate a novel function of two TFs, OVOL1 and OVOL2, as critical inducers of MET in human cancers. Our findings indicate that the OVOL-TFs control MET through a regulatory feedback loop with EMT-inducing TF ZEB1, and the regulation of mRNA splicing by inducing Epithelial Splicing Regulatory Protein 1 (ESRP1). Using mouse prostate tumor models we show that expression of OVOL-TFs in mesenchymal prostate cancer cells attenuates their metastatic potential. The role of OVOL-TFs as inducers of MET is further supported by expression analyses in 917 cancer cell lines, suggesting their role as crucial regulators of epithelial-mesenchymal cell plasticity in cancer