On the Distribution of Stellar Masses in Gamma-ray Burst Host Galaxies

We analyze Spitzer images of 30 long-duration gamma-ray burst (GRB) host galaxies. We estimate their total stellar masses (M_*) based on the rest-frame K-band luminosities (L_K_(rest)) and constrain their star formation rates (SFRs; not corrected for dust extinction) based on the rest-frame UV continua. Further, we compute a mean M_*/ L_K_(rest) = 0.45 M_☉/L_☉. We find that the hosts are low M_*, star-forming systems. The median M_* in our sample ( = 10^(9.7) M_☉) is lower than that of "field" galaxies (e.g., Gemini Deep Deep Survey). The range spanned by M_* is 10^7 M_☉ < M_* < 10^(11) M_☉, while the range spanned by the dust-uncorrected UV SFR is 10^(–2) M_☉ yr^(–1) < SFR < 10 M_☉ yr^(–1). There is no evidence for intrinsic evolution in the distribution of M_* with redshift. We show that extinction by dust must be present in at least 25% of the GRB hosts in our sample and suggest that this is a way to reconcile our finding of a relatively lower UV-based, specific SFR (φ ≡ SFR/M_*) with previous claims that GRBs have some of the highest φ values. We also examine the effect that the inability to resolve the star-forming regions in the hosts has on φ

Follow-up observations from observatories based in Spain

We present a review of the follow-up observations carried out from observatories located in Spain; Calar-Alto, Izanha and Roque de Los Muchachos. It summarizes the observations carried out by our group for 27 GRBs occurred in the period 1999-2000, spanning from GRB 990123 to GRB 001007.Comment: 3 pages, no figures. To appear in the proceedings of the October 2000 Rome Workshop on ``Gamma-Ray Bursts in the Afterglow Era'

Cytoplasmic LSM-1 protein regulates stress responses through the insulin/IGF-1 signaling pathway in Caenorhabditis elegans

This article is distributed exclusively by the RNA Society for the first 12 months after the full-issue publication date. After 12 months, it is available under a Creative Commons License (Attribution-NonCommercial 4.0 International).-- et al.Genes coding for members of the Sm-like (LSm) protein family are conserved through evolution from prokaryotes to humans. These proteins have been described as forming homo-or heterocomplexes implicated in a broad range of RNA-related functions. To date, the nuclear LSm2-8 and the cytoplasmic LSm1-7 heteroheptamers are the best characterized complexes in eukaryotes. Through a comprehensive functional study of the LSm family members, we found that lsm-1 and lsm-3 are not essential for C. elegans viability, but their perturbation, by RNAi or mutations, produces defects in development, reproduction, and motility. We further investigated the function of lsm-1, which encodes the distinctive protein of the cytoplasmic complex. RNA-seq analysis of lsm-1 mutants suggests that they have impaired Insulin/IGF-1 signaling (IIS), which is conserved in metazoans and involved in the response to various types of stress through the action of the FOXO transcription factor DAF-16. Further analysis using a DAF-16:GFP reporter indicated that heat stress-induced translocation of DAF-16 to the nuclei is dependent on lsm-1. Consistent with this, we observed that lsm-1 mutants display heightened sensitivity to thermal stress and starvation, while overexpression of lsm-1 has the opposite effect. We also observed that under stress, cytoplasmic LSm proteins aggregate into granules in an LSM-1-dependent manner. Moreover, we found that lsm-1 and lsm-3 are required for other processes regulated by the IIS pathway, such as aging and pathogen resistance.This work was supported by a grant from the Instituto de Salud Carlos III (ISCIII) (Exp. PI12/01554). R.J. and D.B. were supported by a Natural Sciences and Engineering Research Council (NSERC) Canada grant. D.B. holds a Canada Research Chair. J.C. is a Miguel Servet Researcher (ISCIII). E.C. was supported with a CTP-AIRE fellowship from AGAUR (Generalitat de Catalunya) and a TRANSBIO SUDOE collaborative project.Peer Reviewe

Flight path analysis in sounding rocket “Libertador I” with computational simulation on three degrees of freedom

This paper presents obtained results from computer simulations in order to analyze the flight path of the sounding rocket Libertador I, developed in 2012 at the Fundación Universitaria Los Libertadores. The main aspects that affect the motion of a rocket are propulsion and aerodynamics effects. Numerical algorithms were implemented to value the thrust provided by the rocket motor as well as aerodynamic loads. Then, the differential equations of the motion are solved using the Runge-Kutta method, RK9. Trajectory and other numerical results are calculated from a code developed in FORTRAN. Finally, graphs of the flight path, curves of the vehicle velocity as function of time are presented. Also, the algorithm permits to determine the maximum altitude and possible impact sites.Facultad de Ingenierí

Flight path analysis in sounding rocket “Libertador I” with computational simulation on three degrees of freedom

This paper presents obtained results from computer simulations in order to analyze the flight path of the sounding rocket Libertador I, developed in 2012 at the Fundación Universitaria Los Libertadores. The main aspects that affect the motion of a rocket are propulsion and aerodynamics effects. Numerical algorithms were implemented to value the thrust provided by the rocket motor as well as aerodynamic loads. Then, the differential equations of the motion are solved using the Runge-Kutta method, RK9. Trajectory and other numerical results are calculated from a code developed in FORTRAN. Finally, graphs of the flight path, curves of the vehicle velocity as function of time are presented. Also, the algorithm permits to determine the maximum altitude and possible impact sites.Facultad de Ingenierí

Dynamic Geometry applications in Descriptive Geometry teaching

RESUMEN Desde su introducción a finales del siglo XVIII por parte de Gaspar Monge, la Geometría Descriptiva se ha mantenido inalterable, sin grandes modificaciones en sus postulados fundacionales. La aparición del CAD, fundamentalmente en sus versiones 3D, ha ocasionado que gran parte de las técnicas propias de la Geometría Descriptiva se hayan quedado obsoletas, sin un uso práctico en la actualidad. Pero los sistemas CAD presentan una serie de inconvenientes para su aplicación docente en las aulas de secundaria y bachillerato, debido a su complejidad de utilización al tener una orientación profesional. Por otra parte, la reciente aparición de sistemas de Geometría Dinámica 3D ha propiciado que estas aplicaciones sean una de las herramientas más recomendadas para su uso en la enseñanza de la geometría espacial en secundaria. En el presente trabajo se plantea la utilización de estos sistemas como herramientas de apoyo a la docencia de la Geometría Descriptiva.ABSTRACT Since its introduction at the end of the 18th century by Gaspar Monge, Descriptive Geometry has remained unchanged, without major modifications to its foundational postulates. The CAD systems development, mainly in their 3D versions, has caused that much of the techniques of Descriptive Geometry have become obsolete, without practical use nowadays. However, CAD systems have some disadvantages in their educational use in secondary and high school educational stages, due to its cumbersome use. On the other hand, the recent development of 3D Dynamic Geometry systems has led to these applications being one of the most recommended tools for their use in high school spatial geometry teaching. In the present work, the use of these systems is proposed as tool to support the teaching of Descriptive Geometry.Máster en Formación del Profesorado de Educación Secundari

Desarrollo de aspectos metodológicos en el diseño de matrices progresivas

RESUMEN: Se da una tendencia creciente hacia los sistemas automatizados de producción en los se trata de controlar y verificar cada uno de los pasos de forma objetiva y fiable y mejorar la seguridad, por consiguiente el modo de trabajar y de diseñar estas instalaciones y cada una de sus etapas se va modificando sustancialmente. De los procesos de fabricación, uno de los de mayor importancia es el de conformado de piezas por medio de matrices. El diseño de estas herramientas, está basado, de forma importante, en la tradición y el empirismo de quienes las realizan, pues intervienen diversos factores que dificultan la sistematización de estos diseños, como son: • El producto a fabricar y las prensas de que se dispone, que caracterizan la matriz a diseñar. • La confluencia de numerosos factores tecnológicos • Muchos de los componentes de una matriz o estampa se han de fabricar de forma específica para ésta. Otros están normalizados, pero su variedad es muy amplia. • Se realiza un modelo para cada pieza a producir (sólo en casos excepcionales son varios) Las matrices progresivas tienen una complejidad añadida, pues realizan numerosos pasos sucesivos en cada golpe de prensa, lo cual permite realizar las piezas, en una sola máquina, optimizando la utilización de recursos. En este trabajo, se trata de contribuir a la sistematización en el diseño de matrices progresivas y de incorporar tecnologías avanzadas de fabricación que faciliten y optimicen las matrices resultantes, aplicando, si es el caso, la simulación del producto.ABSTRACT: There is a tendency toward automated production systems, trying to control every phase and improving the working and designing way of these facilities or tools. Among the manufacturing processes, one of the most important is metal forming by dies. Mainly, the design of dies is based in the tradition and empiricism of designers due to it involves various factors that hinder the systematization o these designs, such as:• The part to manufacture and presses available, whisch define die to design • The confluence of several technological factors • Many components of a die have to be manufactured specifically for each part. Others are standard, but their range is very wide. • Generally only one die is made for each part to be Progressive dies have an extra complexity, because they do many successive operations in each press stroke, which allows to make the parts in only one machine, optimizing the use of the resources. This thesis seeks to contribute to the systematization in progressive die design and incorporating advanced manufacturing technologies that facilitate and optimize the dies design

A nearby GRB host prototype for z~7 Lyman-break galaxies: Spitzer-IRS and X-shooter spectroscopy of the host galaxy of GRB031203

Gamma-ray burst (GRB) host galaxies have been studied extensively in optical photometry and spectroscopy. Here we present the first mid-infrared spectrum of a GRB host, HG031203. It is one of the nearest GRB hosts at z=0.1055, allowing both low and high-resolution spectroscopy with Spitzer-IRS. Medium resolution UV-to-K-band spectroscopy with the X-shooter spectrograph on the VLT is also presented, along with Spitzer IRAC and MIPS photometry, as well as radio and sub-mm observations. These data allow us to construct a UV-to-radio spectral energy distribution with almost complete spectroscopic coverage from 0.3-35 micron of a GRB host galaxy for the first time, potentially valuable as a template for future model comparisons. The IRS spectra show strong, high-ionisation fine structure line emission indicative of a hard radiation field in the galaxy, suggestive of strong ongoing star-formation and a very young stellar population. The selection of HG031203 via the presence of a GRB suggests that it might be a useful analogue of very young star-forming galaxies in the early universe, and hints that local BCDs may be used as more reliable analogues of star-formation in the early universe than typical local starbursts. We look at the current debate on the ages of the dominant stellar populations in z~7 and z~8 galaxies in this context. The nebular line emission is so strong in HG031203, that at z~7, it can reproduce the spectral energy distributions of z-band dropout galaxies with elevated IRAC 3.6 and 4.5 micron fluxes without the need to invoke a 4000A break.Comment: Published in ApJ. 9 pages, 6 figures, emulateapj styl