Radio light curves during the passage of cloud G2 near Sgr A*

We calculate radio light curves produced by the bow shock that is likely to form in front of the G2 cloud when it penetrates the accretion disk of Sgr A*. The shock acceleration of the radio-emitting electrons is captured self-consistently by means of first-principles particle-in-cell simulations. We show that the radio luminosity is expected to reach maximum in early 2013, roughly a month after the bow shock crosses the orbit pericenter. We estimate the peak radio flux at 1.4 GHz to be 1.4 - 22 Jy depending on the assumed orbit orientation and parameters. We show that the most promising frequencies for radio observations are in the 0.1<nu<1 GHz range, for which the bow shock emission will be much stronger than the intrinsic radio flux for all the models considered.Comment: 15 pages, 10 figures, accepted for publication in MNRA

Generation and characterization of nucleic acid aptamers targeting the capsid P domain of a human norovirus GII.4 strain

AbstractHuman noroviruses (NoV) are the leading cause of acute viral gastroenteritis worldwide. Significant antigenic diversity of NoV strains has limited the availability of broadly reactive ligands for design of detection assays. The purpose of this work was to produce and characterize single stranded (ss)DNA aptamers with binding specificity to human NoV using an easily produced NoV target—the P domain protein. Aptamer selection was done using SELEX (Systematic Evolution of Ligands by EXponential enrichment) directed against an Escherichia coli-expressed and purified epidemic NoV GII.4 strain P domain. Two of six unique aptamers (designated M1 and M6-2) were chosen for characterization. Inclusivity testing using an enzyme-linked aptamer sorbent assay (ELASA) against a panel of 14 virus-like particles (VLPs) showed these aptamers had broad reactivity and exhibited strong binding to GI.7, GII.2, two GII.4 strains, and GII.7 VLPs. Aptamer M6-2 exhibited at least low to moderate binding to all VLPs tested. Aptamers significantly (p<0.05) bound virus in partially purified GII.4 New Orleans outbreak stool specimens as demonstrated by ELASA and aptamer magnetic capture (AMC) followed by RT-qPCR. This is the first demonstration of human NoV P domain protein as a functional target for the selection of nucleic acid aptamers that specifically bind and broadly recognize diverse human NoV strains

Cumplimiento de las recomendaciones de práctica de actividad física y percepción de barreras en estudiantes de bachillerato

El objetivo de este estudio fue conocer los niveles de actividad física (AF) así como la percepción de barreras para la realización de AF en estudiantes de Bachillerato, analizando dichas variables en función del género, curso académico, práctica deportiva extraescolar y tipo de jornada. Se realizó un estudio descriptivo transversal en el que participaron 248 adolescentes, 120 chicos y 128 chicas ( M = 15.32; DT = 1.81), 144 de 1º de Bachillerato y 104 de 2º de Bachillerato. Se utilizó el Cuestionario Internacional de AF en su versión corta (IPAQ-SF) y la Escala de Barreras para la práctica de AF . Los resultados señalaron que menos del 30% de los estudiantes de Bachillerato alcanza las recomendaciones de práctica de AF, siendo el grado de cumplimiento más elevado en los chicos (38.3%), en el alumnado de 1º de Bachillerato (30.6%), en el alumnado que realiza práctica deportiva extraescolar (36.7%) y entre semana (31%). Por otro lado, las barreras referentes al tiempo fueron superiores en el alumnado de 2º de Bachillerato, mientras que las barreras relativas al disfrute fueron superiores en las chicas y en el alumnado que no realizaba práctica deportiva extraescolar. Los resultados destacan la importancia de promover la práctica regular de AF en Bachillerato, especialmente en las chicas y en los adolescentes de 2º curso, a través de programas de intervención que ayuden a mejorar la gestión del tiempo de ocio y estimulen el desarrollo de los procesos motivacionales. The aim of this study was to analyze physical activity (PA) levels and perceived barriers to PA in High School students. Similarly, differences in gender, academic year, out-of-school sport and type of day were analyzed among these variables. In this cross-sectional study, 248 adolescents, 120 boys and 128 girls (M = 15.32; SD = 1.81), were involved. The sample was made up of 144 12th grade students (58.1%) and 104 13th grade students. The International PA Questionnaire-Short Form (IPAQ-SF) and the Scale of Barriers to PA were used. The results showed that less than 30% of High School students comply with the PA guidelines, being higher in boys (38.3%), in the 12th High School students (30.6%), in the students who practiced extracurricular sports (36.7%) and weekdays (31%). On the other hand, barriers relating to time adolescents were higher in students of 13th High School, while barriers relate to enjoyment were higher in girls and students who did not practice extracurricular sports. The results highlight the importance of promoting PA in High School students, especially in girls and 12th High School, through intervention programs that help improve the management of their leisure time and development of motivational processes

Engineering higher order Van Hove singularities in two dimensions: the example of the surface layer of Sr2_2RuO4_4

The properties of correlated electron materials are often intricately linked to Van Hove singularities (VHs) in the vicinity of the Fermi energy. The class of these VHs is of great importance, with higher order ones -- with power-law divergence in the density of states -- leaving frequently distinct signatures in physical properties. We use a new theoretical method to detect and analyse higher order Van Hove singularities (HOVHs) in two-dimensional materials and apply it to the electronic structure of the surface layer of Sr$_2$RuO$_4$. We then constrain a low energy model of the VHs of the surface layer of Sr$_2$RuO$_4$ against angle-resolved photoemission spectroscopy and quasiparticle interference data to analyse the VHs near the Fermi level. We show how these VHs can be engineered into HOVHs.Comment: 8 pages including Supplemental Material, 5 figure