Jagiellonian University

About: Jagiellonian University is a education organization based out in Krakow, Poland. It is known for research contribution in the topics: Population & Catalysis. The organization has 17438 authors who have published 44092 publications receiving 862633 citations. The organization is also known as: Academia Cracoviensis & Akademia Krakowska.

SBS 0846+513: a new γ-ray-emitting narrow-line Seyfert 1 galaxy

Abstract: We report Fermi Large Area Telescope (LAT) observations of the radio-loud active galactic nucleus SBS 0846+513 (z = 0.5835), optically classified as a narrow-line Seyfert 1 galaxy, together with new and archival radio-to-X-ray data. The source was not active at γ-ray energies during the first two years of Fermi operation. A significant increase in activity was observed during 2010 October–2011 August. In particular, a strong γ-ray flare was observed in 2011 June reaching an isotropic γ-ray luminosity (0.1–300 GeV) of 1.0 × 10^(48) erg s^(−1), comparable to that of the brightest flat spectrum radio quasars, and showing spectral evolution in γ rays. An apparent superluminal velocity of (8.2 ± 1.5)c in the jet was inferred from 2011 to 2012 Very Long Baseline Array (VLBA) images, suggesting the presence of a highly relativistic jet. Both the power released by this object during the flaring activity and the apparent superluminal velocity are strong indications of the presence of a relativistic jet as powerful as those of blazars. In addition, variability and spectral properties in radio and γ-ray bands indicate blazar-like behaviour, suggesting that, except for some distinct optical characteristics, SBS 0846+513 could be considered as a young blazar at the low end of the blazar's black hole mass distribution.

Sertoli-germ cell junctions in the testis: a review of recent data.

Abstract: Spermatogenesis is a process that involves an array of cellular and biochemical events, collectively culminating in the formation of haploid spermatids from diploid precursor cells known as spermatogonia. As germ cells differentiate from spermatogonia into elongated spermatids, they also progressively migrate across the entire length of the seminiferous epithelium until they reach the luminal edge in anticipation of spermiation at late stage VIII of spermatogenesis. At the same time, these germ cells must maintain stable attachment with Sertoli cells via testis-unique intermediate filament- (i.e. desmosome-like junctions) and actin- (i.e. ectoplasmic specializations, ESs) based cell junctions to prevent sloughing of immature germ cells from the seminiferous epithelium, which may result in infertility. In essence, both desmosome-like junctions and basal ESs are known to coexist between Sertoli cells at the level of the blood–testis barrier where they cofunction with the well-studied tight junction in maintaining the immunological barrier. However, the type of anchoring device that is present between Sertoli and germ cells depends on the developmental stage of the germ cell, i.e. desmosome-like junctions are present between Sertoli and germ cells up to, but not including, step 8 spermatids after which this junction type is replaced by the apical ES. While little is known about the biology of the desmosome-like junction in the testis, we have a relatively good understanding of the molecular architecture and the regulation of the ES. Here, we discuss recent findings relating to these two junction types in the testis, highlighting prospective areas that should be investigated in future studies.

Contemporary practice and technical aspects in coronary intervention with bioresorbable scaffolds: A European perspective

Abstract: Aims Next to patient characteristics, the lack of a standardised approach for bioresorbable vascular scaffold (BVS) implantation is perceived as a potential explanation for the heterogeneous results reported so far To provide some guidance, we sought to find a consensus on the best practices for BVS implantation and management across a broad array of patient and lesion scenarios Methods and results Fourteen European centres with a high volume of BVS procedures combined their efforts in an informal collaboration To get the most objective snapshot of different practices among the participating centres, a survey with 45 multiple choice questions was prepared and conducted The results of the survey represented a basis for the technical advice provided in the document, whereas areas of controversy are highlighted Conclusions Consensus criteria for patient and lesion selection, BVS implantation and optimisation, use of intravascular imaging guidance, approach to multiple patient and lesion scenarios, and management of complications, were identified

Theory of the valley-valve effect in graphene nanoribbons

Abstract: A potential step in a graphene nanoribbon with zigzag edges is shown to be an intrinsic source of intervalley scattering---no matter how smooth the step is on the scale of the lattice constant $a$. The valleys are coupled by a pair of localized states at the opposite edges, which act as an attractor and/or repellor for the edge states propagating in valley $K/{K}^{\ensuremath{'}}$. The relative displacement $\ensuremath{\Delta}$ along the ribbon of the localized states determines the conductance $G$. Our result $G=({e}^{2}/h)[1\ensuremath{-}\text{cos}(N\ensuremath{\pi}+2\ensuremath{\pi}\ensuremath{\Delta}/3a)]$ explains why the ``valley-valve'' effect (the blocking of the current by a $p\text{\ensuremath{-}}n$ junction) depends on the parity of the number $N$ of carbon atoms across the ribbon.