Constraints on feedback processes during the formation of early-type galaxies

Galaxies are found to obey scaling relations between a number of observables. These relations follow different trends at the low- and the high-mass ends. The processes driving the curvature of scaling relations remain uncertain. In this letter, we focus on the specific family of early-type galaxies, deriving the star formation histories of a complete sample of visually classified galaxies from SDSS-DR7 over the redshift range 0.01<z<0.025, covering a stellar mass interval from 10^9 to 3 x 10^11 Msun. Our sample features the characteristic "knee" in the surface brightness vs. mass distribution at Mstar~3 x 10^10 Msun. We find a clear difference between the age and metallicity distributions of the stellar populations above and beyond this knee, which suggests a sudden transition from a constant, highly efficient mode of star formation in high-mass galaxies, gradually decreasing towards the low-mass end of the sample. At fixed mass, our early-type sample is more efficient in building up the stellar content at early times in comparison to the general population of galaxies, with half of the stars already in place by redshift z~2 for all masses. The metallicity-age trend in low-mass galaxies is not compatible with infall of metal-poor gas, suggesting instead an outflow-driven relation.Comment: 12 pages,3 figures, accepted for publication in ApJ

Criterios de instalación de un parque eólico marino

La energía eólica es de las más fuertes en desarrollo y avance dentro del mundo de las renovables. A su vez dentro de este campo, una tecnología aun en desarrollo y con ciertas limitaciones es la relativa a los parques eólicos marinos (u “offshore”). Este trabajo fin de grado surge del interés personal del autor por conocer este tipo de tecnología y todos los aspectos relativos a la instalación de un parque eólico marino que se deben tener en cuenta. Durante este documento se va a hacer mención a las diferentes partes de las que se compone una instalación eólica offshore. Se comenzará tratando las posibles ubicaciones del parque, seguido habrá una breve introducción al cálculo de la potencia del viento del parque (sin olvidar hablar de los tipos de aerogeneradores), posteriormente se definirán los tipos de cimentaciones y subestaciones encargadas en la sostenibilidad de estas instalaciones. Por último, se ha querido tratar como tema principal el cableado submarino, desde los cables utilizados hasta su tendido en el lecho marino. Se quiere recalcar esta última parte como centro del trabajo. Finalmente se comentará brevemente las que se creen simulaciones y normativas importantes referente a la instalación de estos parques eólicos marinos.Wind energy is one of the strongest in development and progress within the renewable energy world. At the same time within this field, a technology still in development and with certain limitations is responsible for offshore wind farms. This final degree project arises from the author’s personal interest about knowing this type of technology and all aspects related to the installation of an offshore wind farm that must be taken into account. During this document, mention will be made of the different parts of an offshore wind installation. It will start by treating the possible locations of the park, followed by a brief introduction to the calculation of the wind power of the park (without forgetting to mention the types of wind turbines), then the types of foundations and substations responsible for the sustainability of these facilities will be defined. Finally, it has been wanted to treat submarine wiring as the main theme, from the cables used to laying on the seabed. We want to emphasize this last part as the center of work. Finally, we will briefly comment on the creation of simulations and important regulations regarding the installation of these offshore wind farms.Ingeniería Eléctric

Propuesta de contenido de un programa de formación a las MIPYMES y EPS, que les permita insertarse con confianza en la implementación de la contratación pública sustentable en el Ecuador

Tesis de MaestríaLa Contratación Pública sustentable supone no solo la satisfacción de las necesidades de las instituciones públicas a través de la implementación de procedimientos de contratación y contratos de bienes, servicios y obras, que se requieran para determinados finalidades y objetivos institucionales, sino la consideración en los citados procedimientos de adquisición y contratos de aspectos adicionales, que tienen que ver con la forma, circunstancias y métodos de producción de las empresas, los componentes de los bienes, servicios y obras a adquirir; los asuntos laborales y situación de los trabajadores así como las consecuencias directas de la producción. La contratación pública sustentable es aquella que integra aspectos sociales, económicos y ambientales en las adquisiciones del estado. Los aspectos éticos que debe acoger una compra pública sustentable es fomentar la participación en los procesos de contratación de empresas que, respecto de sus trabajadores y empleados garanticen condiciones laborales dignas que se acojan al marco legal vigente, y procuren el respeto de los derechos humanos y que sean empresas comprometidas con la leal competencia. En lo que se refiere a los aspectos ambientales la contratación pública sustentable procura que generar en los proveedores compromisos relacionados con el cuidado ambiental, que favorezcan una vida saludable a los ciudadanos y la conservación del planeta. Por lo tanto, la administración pública buscará a través de la contratación pública sustentable, que los proveedores asuman compromisos de inclusión social, facilitando la participación en la producción de sus bienes, servicios y obras, a sectores vulnerables de la economía, como mujeres, personas con discapacidad y otros sectores que generalmente han sufrido discriminación laboral por sus particulares circunstancias. En el presente estudio se busca proponer mecanismos que permitan desarrollar en el Ecuador este tipo de contratación pública sustentable, necesaria para un mejor desarrollo social de sus habitantes, no solo como factores económicos del país sino sobre todo como parte de un conglomerado social que actúa en función del todo, para el crecimiento de todos. Por lo que este trabajo intenta ser una herramienta que contribuya a generar buenas prácticas que motiven la inclusión de cláusulas que promuevan la contratación pública sustentable, que facilite a la administración pública ecuatoriana actuar dentro de un marco de principios éticos, ambientales y sociales como parte de la cadena de provisión de bienes y contratación de servicios y obras.Fil: Estrada de la Rosa, José Ignacio . Universidad Nacional de San Martín. Escuela de Política y Gobiern

Discovery of true, likely and possible symbiotic stars in the dwarf spheroidal NGC 205

In this paper we discuss the photometric and spectroscopic observations of newly discovered (symbiotic) systems in the dwarf spheroidal galaxy NGC 205. The Gemini Multi-Object Spectrograph on-off band [O III] 5007 A emission imaging highlighted several [O III] line emitters, for which optical spectra were then obtained (Gon\c{c}alves et al. 2014). The detailed study of the spectra of three objects allow us to identify them as true, likely and possible symbiotic systems (SySts), the first ones discovered in this galaxy. SySt-1 is unambiguously classified as a symbiotic star, because of the presence of unique emission lines which belong only to symbiotic spectra, the well known O VI Raman scattered lines. SySt-2 is only possibly a SySt because the Ne VII Raman scattered line at 4881 A, recently identified in a well studied Galactic symbiotic as another very conspicuous property of symbiotic, could as well be identified as N III or [Fe III]. Finally, SySt-3 is likely a symbiotic binary because in the red part of the spectrum it shows the continuum of a late giant, and forbidden lines of moderate- to high-ionization, like [Fe v] 4180 A. The main source for skepticism on the symbiotic nature of the latter systems is their location in the PN region in the [O III] 4363/H\gamma\ vs [O III] 5007/H\beta\ diagnostic diagram (Gutierrez-Moreno et al. 1995). It is worth mentioning that at least another two confirmed symbiotics, one of the Local Group dwarf spheroidal IC 10 and the other of the Galaxy, are also misplaced in this diagram.Comment: 8 pages, 5 figures, accepted for publication in MNRAS

The fate of high-redshift massive compact galaxies

Massive high-redshift quiescent compact galaxies (nicknamed red nuggets) have been traditionally connected to present-day elliptical galaxies, often overlooking the relationships that they may have with other galaxy types. We use large bulge–disc decomposition catalogues based on the Sloan Digital Sky Survey to check the hypothesis that red nuggets have survived as compact cores embedded inside the haloes or discs of present-day massive galaxies. In this study, we designate a compact core as the bulge component that satisfies a prescribed compactness criterion. Photometric and dynamic mass–size and mass–density relations are used to show that, in the inner regions of galaxies at z ∼ 0.1, there are abundant compact cores matching the peculiar properties of the red nuggets, an abundance comparable to that of red nuggets at z ∼ 1.5. Furthermore, the morphology distribution of the present-day galaxies hosting compact cores is used to demonstrate that, in addition to the standard channel connecting red nuggets with elliptical galaxies, a comparable fraction of red nuggets might have ended up embedded in discs. This result generalizes the inside-out formation scenario; present-day massive galaxies can begin as dense spheroidal cores (red nuggets), around which either a spheroidal halo or a disc is formed later

Use of tissue chromogranin A as chronic and acute stress marker in fish

Chromogranin A (CgA) has recently reported as stress marker in superior vertebrates. It is stored in granules of the chromaffin tissue and released to the bloodstream from the adrenal medulla and pituitary after stress situations. The objective of this work was to study the chromogranin A variation for acute and chronic stress in fish, aiming at determining if those proteins could be suitable stress markers. A chronic stress experiment was conducted consisting of two treatments, stressed and control meagres (Argyrosomus regius) for 6 months. The stressed groups were submitted to confinement and netting/chasing stress. The control group tanks were not disturbed along the experiment. A complementary acute stress challenge was performed exposing control fish to air for 3 min. Fish were sampled for blood, tissues and biometry. Plasma lactate and cortisol increased significantly after acute stress although glucose and proteins remained stable, and kidney cortisol and brain adrenaline were significantly higher. Kidney CgA decreased significantly in the acute stressed fish though brain CgA did not change. Final weight and length, growth and condition index were significantly lower in chronically stressed fish, though survival rate was not different between treatments. Plasma markers did not change significantly though kidney cortisol increased in chronically stressed fish. Brain noradrenaline was lower in chronically stressed fish. Both brain and kidney CgA concentrations decreased in stressed (chronic and acute) fish. Concluding, only kidney CgA and cortisol kept the same variation pattern in both stress types. Although cortisol concentrations in plasma and tissues have been widely studied, the tissue CgA concentrations related to stress have not still reported in fish. Initially, the depletion of kidney CgA could be considered as a chronic stress marker though it needs to be supported by future research.M. Herrera’s contract is supported by the Emergia Program (PAIDI 2020), from Junta de Andalucía. N. Salamanca’s pre-doc contract is cofinanced by the European Social Fund (FSE) through the call “Ayudas para contratos predoctorales para la formaci´on de doctores 2017” from the AEI. Funding for open access charge: Universidad de Huelva / CBUA

Climate-Dependent Groundwater Discharge on Semi-Arid Inland Ephemeral Wetlands: Lessons from Holocene Sediments of Lagunas Reales in Central Spain

Wetlands are environments whose water balance is highly sensitive to climate change and human action. This sensitivity has allowed us to explore the relationships between surface water and groundwater in the long term as their sediments record all these changes and go beyond the instrumental/observational period. The Lagunas Reales, in central Spain, is a semi-arid inland wetland endangered by both climate and human activity. The reconstruction of the hydroclimate and water levels from sedimentary facies, as well as the changes in the position of the surface water and groundwater via the record of their geochemical fingerprint in the sediments, has allowed us to establish a conceptual model for the response of the hydrological system (surface water and groundwater) to climate. Arid periods are characterized by low levels of the deeper saline groundwater and by a greater influence of the surface freshwater. A positive water balance during wet periods allows the discharge of the deeper saline groundwater into the wetland, causing an increase in salinity. These results contrast with the classical model where salinity increases were related to greater evaporation rates and this opens up a new way of understanding the evolution of the hydrology of wetlands and their resilience to natural and anthropogenic changes