On the nature of the variable gamma-ray sources at low galactic latitudes

Population studies of EGRET gamma-ray sources indicate that there is a distinctive population of bright sources at low galactic latitudes. The sources have a distribution consistent with that of young galactic objects, with a concentration toward the inner spiral arms. There is a subgroup that displays strong variability with timescales from days to months. Following an earlier suggestion by Kaufman Bernadó et al. (2002), we explore the possibility that these sources could be high-mass microquasars. Detailed models for the gamma-ray emission that include inverse Compton interactions of electrons in the relativistic jets and photons from all local fields (stellar UV photons, synchrotron photons, soft X-ray photons from the accretion disk, and hard X-ray photons from a corona) are presented. We conclude that microquasars are excellent candidates for the parent population of the subgroup of variable low-latitude EGRET sources.Fil: Bosch Ramon, Valentí. Universidad de Barcelona; EspañaFil: Romero, Gustavo Esteban. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Paredes, Josep Maria. Universidad de Barcelona; Españ

Propuesta de un plan de seguridad y salud en el trabajo basado en la norma 29783 para minimizar riesgos laborales en la empresa Metalarc S. R. L., Cajamarca, 2017

En la presente tesis denominada “Propuesta de un plan de seguridad y salud en el trabajo basado en la norma 29783 para minimizar riesgos laborales en la empresa Metalarc S.R.L, Cajamarca, 2017.”, se propuso un plan de seguridad para minimizar los riesgos en la empresa metalmecánica Metalarc SRL., tomando como población y muestra a la empresa metalmecánica en su conjunto. El tipo de investigación fue Aplicada – Descriptiva – No experimental. Las técnicas de recolección de información estuvo documentada por cuestionarios y encuestas distribuidas a los trabajadores de la empresa, siguiendo un esquema lógico y técnico-estadístico, apreciándose el incumplimiento de la ley 29783. No tienen áreas encargadas de Seguridad y Salud ocupacional. No existe documentación de registro de incidentes, así como métodos de identificación y control de peligros. En la planificación se propuso los objetivos y metas con sus respectivos indicadores, la cual sirvió de base para el diseño del programa de seguridad y salud en el trabajo. Se utilizó los formatos de la resolución ministerial RM- 050-2013. Se realizó el resumen de acuerdo a los controles propuestos en el IPER. El costo de la implementación de la propuesta asciende a S/. 9 325.00. El proyecto es viable, es decir a la empresa metalmecánica Metalarc SRL le conviene la implementación de la propuesta del sistema de gestión de seguridad y salud en el trabajo y ello es corroborado por el VAN el cual fue de S/. 15 512.81, un TIR de 61 % y un B/C = 1.0143. PALABRAS CLAVE: plan de seguridad, accidente, metalmecánica.In the present thesis entitled "Proposal of a safety and health at work plan based on the 29783 standard to minimize occupational hazards in the welding area of Metalarc SRL, Cajamarca, 2017.", a safety plan was proposed for minimize the risks in the metallurgical company Metalarc SRL., taking as a population and showing the metal-mechanic company as a whole. The type of research was Applied - Descriptive - Not experimental. The information collection techniques were documented by questionnaires and surveys distributed to the company's workers, following a logical and technical-statistical scheme, appreciating the breach of law 29783. They do not have areas in charge of Occupational Health and Safety. There is no documentation of incident registration, as well as methods of identification and control of hazards. In planning, the objectives and goals were proposed with their respective indicators, which served as the basis for the design of the occupational health and safety program. The formats of ministerial resolution RM-0502013 were used. The summary was made according to the controls proposed in the IPER. The cost of implementing the proposal amounts to S /. 9 325.00. The project is viable, that is to say, the metallurgical company Metalarc SRL will benefit from the implementation of the proposal of the occupational safety and health management system and this is corroborated by the VAN, which was S /. 15 512.81, a TIR of 61% and a B / C = 1.0143. KEY WORD: safety plan, accident, metalworking

The radio to TeV orbital variability of the microquasar LSI+61303

Context: .The microquasar LS I +61 303 has recently been detected at TeV energies by the Cherenkov telescope MAGIC, presenting variability on timescales similar to its orbital period. This system has been intensively observed at different wavelengths during the last three decades, showing a very complex behavior along the orbit.Aims: .We aim to explain, using a leptonic model in the accretion scenario, the observed orbital variability and spectrum from radio to TeV energies of LS I +61 303.Methods: .We apply a leptonic model based on accretion of matter from the slow inhomogeneous equatorial wind of the primary star, assuming particle injection proportional to the accretion rate. The relativistic electron energy distribution within the binary system is computed taking into account convective/adiabatic and radiative losses. The spectral energy distribution (SED) has been calculated accounting for synchrotron and (Thomson/Klein Nishina -KN-) inverse Compton (IC) processes and the photon-photon absorption in the ambient photon fields. The angle dependence of the photon-photon and IC cross sections has been considered in the calculations.Results: .We reproduce the main features of the observed light curves from LS I +61 303 at radio, X-rays, high-energy (HE), and very high-energy (VHE) gamma-rays, and the whole spectral energy distribution.Conclusions: .Our model is able to explain the radio to TeV orbital variability taking into account that radiation along the orbit is strongly affected by the variable accretion rate, the magnetic field strength, and by the ambient photon field via dominant IC losses and photon-photon absorption at periastron.Fil: Bosch Ramon, Valentí. Universidad de Barcelona; EspañaFil: Paredes, Josep Maria. Universidad de Barcelona; EspañaFil: Romero, Gustavo Esteban. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Ribó, Marc. Universidad de Barcelona; Españ

Episodic gamma-ray and neutrino emission from the low mass X-ray binary GRO J0422+32

GRO J0422+32 is a member of the class of low-mass X-ray binary (LMXB) sources, discovered during an outburst in 1992. Along the entire episode ($\sim 230$ days) a persistent power-law spectral component extending up to $\sim 1$ MeV was observed. These results suggest that non-thermal processes must be at work in the system. We apply a corona model to describe the spectrum of GRO J0422+32 during the flaring phase. We study relativistic particle interactions solving the transport equations for all type of particles self-consistently. We fit the electromagnetic emission during the plateau phase of the event and estimate the emission during an energetic episode, as well as the neutrino production. Our work leads to predictions that can be tested by the new generation of very high energy gamma-ray instruments.Comment: HIGH ENERGY GAMMA-RAY ASTRONOMY: 5th International Meeting on High Energy Gamma-Ray Astronomy. AIP Conference Proceedings, Volume 1505, pp. 410-413 (2012

Gamma-rays from massive protostars

Massive protostars have associated bipolar outflows with velocities of hundreds of km/s. Such outflows produce strong shocks when interact with the ambient medium leading to regions of non-thermal radio emission. Under certain conditions, the population of relativistic particles accelerated at the terminal shocks of the protostellar jets can produce significant gamma-ray emission. We estimate the conditions necessary for high-energy emission in the non-thermal hot spots of jets associated with massive protostars embedded in dense molecular clouds. Our results show that particle-matter interactions can lead to the detection of molecular clouds hosting massive young stellar objects by the Fermi satellite at MeV-GeV energies and even by Cherenkov telescope arrays in the GeV-TeV range. Astronomy at gamma-rays can be used to probe the physical conditions in star forming regions and particle acceleration processes in the complex environment of massive molecular clouds.Comment: Proceeding of the conference "High Energy Phenomena in Massive Stars". Jaen (Spain), 2-5 February 200

Decisión final: ¿Quién se beneficia con las holguras del cronograma en los proyectos de construcción?

In the context of construction disputes, this article responds to a frequent question in the analysis of controversies involving extension of time and helps to simplify the discussion and its consequences.En el contexto de las disputas en construcción, este artículo responde a una pregunta frecunte en el análisis de controversias sobre ampliación de plazo y aporta utilidad en simplificar la discusión y sus consecuencias

A broadband leptonic model for gamma-ray emitting microquasars

Observational and theoretical studies point to microquasars (MQs) as possible counterparts of a significant fraction of the unidentifiedgamma-ray sources detected so far. At present, a proper scenario to explain the emission beyond soft X-rays from these objects is not known, nor what the precise connection is between the radio and the high-energy radiation. We develop a new model where the MQ jet is dynamically dominated by cold protons and radiatively dominated by relativistic leptons. The matter content and power of the jet are both related with the accretion process. The magnetic field is assumed to be close to equipartition, although it is attached to and dominated by the jet matter. For the relativistic particles in the jet, their maximum energy depends on both the acceleration efficiency and the energy losses. The model takes into account the interaction of the relativistic jet particles with the magnetic field and all the photon and matter fields. Such interaction produces significant amounts of radiation from radio to very high energies through synchrotron, relativistic Bremsstrahlung, and inverse Compton (IC) processes. Variability of the emission produced by changes in the accretion process (e.g. via orbital eccentricity) is also expected. The effects of the gamma-ray absorption by the external photon fields on the gamma-ray spectrum have been taken into account, revealing clear spectral features that might be observed. This model is consistent to the accretion scenario, energy conservation laws, and current observational knowledge, and can provide deeper physical information of the source when tested against multiwavelength data.Facultad de Ciencias Astronómicas y GeofísicasInstituto Argentino de Radioastronomí

Exploring the association of Fermi sources with Young Stellar Objects

Massive protostars have associated bipolar outflows which can produce strong shocks when interact with the surrounding medium. Some theoretical models predict that particle acceleration at relativistic velocities can occur leading to gamma ray emission. In order to identify young stellar objects (YSO) that might emit gamma rays, we have crossed the Fermi First Year Catalog with catalogs of known YSOs, obtaining a set of candidates by spatial correlation. We have conducted Montecarlo simulations to find the probability of chance coincidence. Our results indicate that ∼70% of the candidates should be gamma-ray sources with a confidence of ∼5ρ. σ International Astronomical Union 2011.Instituto Argentino de Radioastronomí

Exploring the association of Fermi sources with Young Stellar Objects

Massive protostars have associated bipolar outflows which can produce strong shocks when interact with the surrounding medium. Some theoretical models predict that particle acceleration at relativistic velocities can occur leading to gamma ray emission. In order to identify young stellar objects (YSO) that might emit gamma rays, we have crossed the Fermi First Year Catalog with catalogs of known YSOs, obtaining a set of candidates by spatial correlation. We have conducted Montecarlo simulations to find the probability of chance coincidence. Our results indicate that ∼70% of the candidates should be gamma-ray sources with a confidence of ∼5ρ. σ International Astronomical Union 2011.Instituto Argentino de Radioastronomí