2,294 research outputs found
Starburst radio galaxies: general properties, evolutionary histories and triggering
In this paper we discuss the results of a programme of spectral synthesis
modelling of a sample of starburst radio galaxies in the context of scenarios
for the triggering of the activity and the evolution of the host galaxies. The
starburst radio galaxies -- comprising ~15 - 25% of all powerful extragalactic
radio sources -- frequently show disturbed morphologies at optical wavelengths,
and unusual radio structures, although their stellar masses are typical of
radio galaxies as a class. In terms of the characteristic ages of their young
stellar populations (YSP), the objects can be divided into two groups: those
with YSP ages t_ysp < 0.1 Gyr, in which the radio source has been triggered
quasi-simultaneously with the main starburst episode, and those with older YSP
in which the radio source has been triggered or re-triggered a significant
period after the starburst episode. Combining the information on the YSP with
that on the optical morphologies of the host galaxies, we deduce that the
majority of the starburst radio galaxies have been triggered in galaxy mergers
in which at least one of the galaxies is gas rich. However, the triggering (or
re-triggering) of the radio jets can occur immediately before, around, or a
significant period after the final coalescence of the merging nuclei,
reflecting the complex gas infall histories of the merger events. Overall, our
results provide further evidence that powerful radio jet activity can be
triggered via a variety of mechanisms, including different evolutionary stages
of major galaxy mergers; clearly radio-loud AGN activity is not solely
associated with a particular stage of a unique type of gas accretion event.Comment: 16 pages, 3 Figures, accepted for publication in MNRA
Synthesis Of Ag@silica Nanoparticles By Assisted Laser Ablation.
This paper reports the synthesis of silver nanoparticles coated with porous silica (Ag@Silica NPs) using an assisted laser ablation method. This method is a chemical synthesis where one of the reagents (the reducer agent) is introduced in nanometer form by laser ablation of a solid target submerged in an aqueous solution. In a first step, a silicon wafer immersed in water solution was laser ablated for several minutes. Subsequently, an AgNO3 aliquot was added to the aqueous solution. The redox reaction between the silver ions and ablation products leads to a colloidal suspension of core-shell Ag@Silica NPs. The influence of the laser pulse energy, laser wavelength, ablation time, and Ag(+) concentration on the size and optical properties of the Ag@Silica NPs was investigated. Furthermore, the colloidal suspensions were studied by UV-VIS-NIR spectroscopy, X-Ray diffraction, and high-resolution transmission electron microscopy (HRTEM).1039
Extreme Starbursts in the Local Universe
The "Extreme starbursts in the local universe" workshop was held at the
Insituto de Astrofisica de Andalucia in Granada, Spain on 21-25 June 2010.
Bearing in mind the advent of a new generation of facilities such as JWST,
Herschel, ALMA, eVLA and eMerlin, the aim of the workshop was to bring together
observers and theorists to review the latest results. The purpose of the
workshop was to address the following issues: what are the main modes of
triggering extreme starbursts in the local Universe? How efficiently are stars
formed in extreme starbursts? What are the star formation histories of local
starburst galaxies? How well do the theoretical simulations model the
observations? What can we learn about starbursts in the distant Universe
through studies of their local counterparts? How important is the role of
extreme starbursts in the hierarchical assembly of galaxies? How are extreme
starbursts related to the triggering of AGN in the nuclei of galaxies? Overall,
41 talks and 4 posters with their corresponding 10 minutes short talks were
presented during the workshop. In addition, the workshop was designed with
emphasis on discussions, and therefore, there were 6 discussion sessions of up
to one hour during the workshop. Here is presented a summary of the purposes of
the workshop as well as a compilation of the abstracts corresponding to each of
the presentations. The summary and conclusions of the workshop along with a
description of the future prospects by Sylvain Veilleux can be found in the
last section of this document. A photo of the assistants is included.Comment: worksho
El abandono y el rezago universitarios de estudiantes de la Facultad de Ciencias Agropecuarias de la Universidad Nacional de Córdoba
Este trabajo es un avance de los resultados obtenidos sobre las trayectorias académicas interrumpidas de estudiantesque cursan la Carrera de Ingeniería Agronómica de la Universidad Nacional de Córdoba, pertenecientes a las cohortes2006-2016. La misma surge ante la necesidad de indagar sobre las causas de interrupción de su actuación académica,como así también del rezago académico, en pos de implementar estrategias de inclusión socio-educativas. Se trata deun estudio exploratorio y descriptivo que utiliza metodologías provenientes del enfoque cuantitativo y cualitativo. Parael análisis e interpretación de datos cuantitativos se utilizó el Análisis Multivariado de Correspondencias Múltiples, ypara los datos cualitativos, el método de comparación constante, y elaboración de categorías y patrones analíticosemergentes. Los resultados obtenidos dan cuenta de los factores endógenos y exógenos que inciden directa oindirectamente en los rendimientos académicos y como consecuencia en el abandono y rezago universitarios.Fil: Romero, C.. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; ArgentinaFil: Moreno, C.. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; ArgentinaFil: Sabadías, Monica Graciela. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; ArgentinaFil: Villar, M.. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; ArgentinaFil: Rodriguez Pesce, Eduardo. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; ArgentinaFil: Acuña, Narda Isabel. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Unidad de Fitopatología y Modelización Agrícola - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Unidad de Fitopatología y Modelización Agrícola; ArgentinaFil: Ordoñez, Adriana. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; ArgentinaFil: Rindertsma, L.. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; ArgentinaFil: Bruno, Cecilia Ines. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Unidad de Fitopatología y Modelización Agrícola - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Unidad de Fitopatología y Modelización Agrícola; Argentin
Plasma?-III tubulin, neurofilament light chain and glial fibrillary acidic protein are associated with neurodegeneration and progression in schizophrenia
Schizophrenia is a progressive disorder characterized by multiple psychotic relapses. After every relapse, patients may not fully recover, and this may lead to a progressive loss of functionality. Pharmacological treatment represents a key factor to minimize the biological, psychological and psychosocial impact of the disorder. The number of relapses and the duration of psychotic episodes induce a potential neuronal damage and subsequently, neurodegenerative processes. Thus, a comparative study was performed, including forty healthy controls and forty-two SZ patients divided into first-episode psychosis (FEP) and chronic SZ (CSZ) subgroups, where the CSZ sub group was subdivided by antipsychotic treatment. In order to measure the potential neuronal damage, plasma levels of beta-III tubulin, neurofilament light chain (Nf-L), and glial fibrillary acidic protein (GFAP) were performed. The results revealed that the levels of these proteins were increased in the SZ group compared to the control group (P < 0.05). Moreover, multiple comparison analysis showed highly significant levels of beta-III tubulin (P = 0.0002), Nf-L (P = 0.0403) and GFAP (P < 0.015) in the subgroup of CSZ clozapine-treated. In conclusion, beta-III tubulin, Nf-L and GFAP proteins may be potential biomarkers of neurodegeneration and progression in SZ
Influence of the LILRA3 Deletion on Multiple Sclerosis Risk : Original Data and Meta-Analysis
Altres ajuts: Junta de Andalucía (JA)- Fondos Europeos de Desarrollo Regional (FEDER) (grant number CTS2704 to FM).Multiple sclerosis (MS) is a neurodegenerative, autoimmune disease of the central nervous system. Genome-wide association studies (GWAS) have identified over hundred polymorphisms with modest individual effects in MS susceptibility and they have confirmed the main individual effect of the Major Histocompatibility Complex. Additional risk loci with immunologically relevant genes were found significantly overrepresented. Nonetheless, it is accepted that most of the genetic architecture underlying susceptibility to the disease remains to be defined. Candidate association studies of the leukocyte immunoglobulin-like receptor LILRA3 gene in MS have been repeatedly reported with inconsistent results. In an attempt to shed some light on these controversial findings, a combined analysis was performed including the previously published datasets and three newly genotyped cohorts. Both wild-type and deleted LILRA3 alleles were discriminated in a single-tube PCR amplification and the resulting products were visualized by their different electrophoretic mobilities. Overall, this meta-analysis involved 3200 MS patients and 3069 matched healthy controls and it did not evidence significant association of the LILRA3 deletion [carriers of LILRA3 deletion: p = 0.25, OR (95% CI) = 1.07 (0.95-1.19)], even after stratification by gender and the HLA-DRB1*15 : 01 risk allele
The role of Prenatal Care and Social Risk Factors in the relationship between immigrant status and neonatal morbidity: A retrospective cohort study
Background and Aim Literature evaluating association between neonatal morbidity and immigrant status presents contradictory results. Poorer compliance with prenatal care and greater social risk factors among immigrants could play roles as major confounding variables, thus explaining contradictions. We examined whether prenatal care and social risk factors are confounding variables in the relationship between immigrant status and neonatal morbidity. Methods Retrospective cohort study: 231 pregnant African immigrant women were recruited from 2007–2010 in northern Spain. A Spanish population sample was obtained by simple random sampling at 1:3 ratio. Immigrant status (Spanish, Sub-Saharan and Northern African), prenatal care (Kessner Index adequate, intermediate or inadequate), and social risk factors were treated as independent variables. Low birth weight (LBW < 2500 grams) and preterm birth (< 37 weeks) were collected as neonatal morbidity variables. Crude and adjusted odds ratios (OR) were estimated by unconditional logistic regression with 95% confidence intervals (95% CI). Results Positive associations between immigrant women and higher risk of neonatal morbidity were obtained. Crude OR for preterm births in Northern Africans with respect to nonimmigrants was 2.28 (95% CI: 1.04–5.00), and crude OR for LBW was 1.77 (95% CI: 0.74–4.22). However, after adjusting for prenatal care and social risk factors, associations became protective: adjusted OR for preterm birth = 0.42 (95% CI: 0.14–1.32); LBW = 0.48 (95% CI: 0.15–1.52). Poor compliance with prenatal care was the main independent risk factor associated with both preterm birth (adjusted OR inadequate care = 17.05; 95% CI: 3.92–74.24) and LBW (adjusted OR inadequate care = 6.25; 95% CI: 1.28–30.46). Social risk was an important independent risk factor associated with LBW (adjusted OR = 5.42; 95% CI: 1.58– 18.62). Conclusions Prenatal care and social risk factors were major confounding variables in the relationship between immigrant status and neonatal morbidity
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