New solutions of the D-dimensional Klein-Gordon equation via mapping onto the nonrelativistic one-dimensional Morse potential

New exact analytical bound-state solutions of the D-dimensional Klein-Gordon equation for a large set of couplings and potential functions are obtained via mapping onto the nonrelativistic bound-state solutions of the one-dimensional generalized Morse potential. The eigenfunctions are expressed in terms of generalized Laguerre polynomials, and the eigenenergies are expressed in terms of solutions of irrational equations at the worst. Several analytical results found in the literature, including the so-called Klein-Gordon oscillator, are obtained as particular cases of this unified approac

Absence of Klein's paradox for massive bosons coupled by nonminimal vector interactions

A few properties of the nonminimal vector interactions in the Duffin-Kemmer-Petiau theory are revised. In particular, it is shown that the space component of the nonminimal vector interaction plays a peremptory role for confining bosons whereas its time component contributes to the leakage. Scattering in a square step potential with proper boundary conditions is used to show that Klein's paradox does not manifest in the case of a nonminimal vector coupling

Copper and Barium Abundances in the Ursa Major Moving Group

We present Cu and Ba abundances for 7 G-K dwarf stars, members of the solar-metallicity, 0.3 Gyr old Ursa Major Moving Group. All analyzed member stars show [Ba/Fe] excesses of +0.3-plus, associated with [Cu/Fe] deficiencies of up to -0.23 dex. The present results suggest that there is an anti-correlation between the abundances of Cu and the heavy elements produced by the main component of the neutron capture s-process. Other possible anomalies are Na and C deficiencies with respect to normal solar-metallicity stars. The new data do not confirm the recent claim that the group member HR6094 is a Ba dwarf star.Comment: 8 pages, 6 figures, accepted to MNRA

Hemisphere Mixing: a Fully Data-Driven Model of QCD Multijet Backgrounds for LHC Searches

A novel method is proposed here to precisely model the multi-dimensional features of QCD multi-jet events in hadron collisions. The method relies on the schematization of high-pT QCD processes as 2->2 reactions made complex by sub-leading effects. The construction of libraries of hemispheres from experimental data and the definition of a suitable nearest-neighbor-based association map allow for the generation of artificial events that reproduce with surprising accuracy the kinematics of the QCD component of original data, while remaining insensitive to small signal contaminations. The method is succinctly described and its performance is tested in the case of the search for the hh->bbbb process at the LHC.Comment: 4 pages plus header, 1 figure, proceedings of EPS 2017 Venic

Modificaciones fisarias en el conejo inducidas por campos electromagnéticos

Se efectúa un estudio experimental para valorar los efectos de campos electromagnéticos de dos intensidades diferentes (2,4 y 10 Gauss) sobre la fisis de huesos largos. Se emplearon 45 conejos de 4 semanas divididos en tres grupos de 15 animales, a los que se colocó unas bobinas de Helmholtz en la rodilla derecha durante ocho horas diarias. Cinco animales de cada grupo fueron estimulados (subgrupo testigo). El primer grupo se sacrificó tras cuatro semanas, el segundo tras 12 semanas y el tercero llevó las bovinas durante 12 semanas y luego se sacrificó 12 semanas después para comprobar la duración de los efectos de la corriente. Los resultados demuestran que la diferencia en longitud entre los huesos estimulados y sus contralaterales fue mayor en el subgrupo sometido a 10 Gauss, aunque en ningún caso superior al 2,5%. La altura fisaria fue mayor en los huesos estimulados que en sus contralaterals, aunque no se apreciaron otras diferencias histológicas. No obstante, el cierre de la fisis se retrasó en todos los huesos estimulados con 10 Gauss y evolucionó normalmente en el resto. Los huesos de los subgrupos testigo no mostraron diferencias entre ellos.This study was carried out to compare the effects of two different electromagnetic fields (2,4 and 10 Gauss) on the growth plate of long bones. Forty five 4-week-old rabbits were divided in three groups of 15 animals each. All of them wore two Helmholtz coils on their right knee for 8 hours daily and then were sacrificed, the first after for 4 weeks, the second one after 12 weeks and the third one after 24 weeks. In this last group the coils were removed after 12 weeks and the animals allowed to live other 12 weeks to study the evolution of the growth plate after cesation of the stimulation. In each group, animals were not stimulated (sham subgroup). Results showed a greater difference in length in those bones stimulated with 10 Gauss, in respect to their contralateral, than the other subgroups. However these differences were less than 2,5% of the total length of the bone. Growth plate height of stimulated bones was greater than their contralateral in all subgroups with no other remarkable histological differences. Closure of the growth plate was delayed in the 10 Gauss stimulated bones but not in the rest. No differences were found among bones of sham subgroups at any time

Acceso abierto a la información científica y técnica en Empresa Brasileña de Investigación Agropecuária (Embrapa): relato de experiencia.

La Empresa Brasileña de Investigación Agropecuaria (Embrapa) desarrolla, desde 2009, "Acceso abierto en Embrapa: maximizar el impacto de la investigación, la visibilidad y la gestion de la información científica", que tiene como objetivo fomentar la transferencia de tecnologías producidas por la Empresa, así como el aumento de la visibilidad de la producción científica de sus investigadores y de la propia institución, al maximizar el acceso a la produción intelectual y la expansión de resultados de investigaciones realizadas. El proyecto es coordenado por Embrapa Información Tecnológica en colaboración con otros centros de investigación y ejecutado principamente por los bibliotecólogos que forman el Sistema de Bibliotecas de Embrapa. El objetivo de este trabajo es contribuir a las iniciativas de evaluación de sus repositorios institucionales: Repositorio de Acceso Abierto a la Información Científica (Alice) y al Servicio de Información Tecnológica en la Agricultura (Infoteca-e)

Comparison of solar radio and EUV synoptic limb charts during the present solar maximum

The present solar cycle is particular in many aspects: it had a delayed rising phase, it is the weakest of the last 100 years, and it presents two peaks separated by more than one year. To understand the impact of these characteristics on the solar chromosphere and coronal dynamics, images from a wide wavelength range are needed. In this work we use the 17~GHz radio continuum, formed in the upper chromosphere and the EUV lines 304 and 171~{\AA}, that come from the transition region (He II) and the corona (Fe IX, X), respectively. We analyze daily images at 304 and 171~{\AA} obtained by the Atmospheric Imaging Assembly (AIA). The 17~GHz maps were obtained by the Nobeyama Radioheliograph (NoRH). To construct synoptic limb charts, we calculated the mean emission of delimited limb areas with 100" wide and angular separation of $5^\circ$. At the equatorial region, the results show an hemispheric asymmetry of the solar activity. The northern hemisphere dominance is coincident with the first sunspot number peak, whereas the second peak occurs concurrently with the increase in the activity at the south. The polar emission reflects the presence of coronal holes at both EUV wavelengths, moreover, the 17~GHz polar brightenings can be associated with the coronal holes. Until 2013, both EUV coronal holes and radio polar brightenings were more predominant at the south pole. Since then they have not been apparent in the north, but thus appear in the beginning of 2015 in the south as observed in the synoptic charts. This work strengthens the association between coronal holes and the 17~GHz polar brightenings as it is evident in the synoptic limb charts, in agreement with previous case study papers. The enhancement of the radio brightness in coronal holes is explained by the presence of bright patches closely associated with the presence of intense unipolar magnetic fields.Comment: 6 pages, 5 figures. Acccepted for publication in Astronomy & Astrophysic