5,433 research outputs found
The hosts of QSOs
We present results of the hosts of four high-redshift () and
high luminosity (M_B \lsim -28 mag) QSOs, three radio-quiet one radio-loud,
imaged in R and K bands. The extensions to the nuclear unresolved source are
most likely due to the hosts galaxies of these QSOs, with luminosities at
rest-frame 2300\AA of at least 3-7% of the QSO luminosity, and most likely
around 6-18% of the QSO luminosity. Our observations show that, if the
extensions we have detected are indeed galaxies, extraordinary big and luminous
host galaxies are not only a characteristic of radio-loud objects, but of QSOs
as an entire class.Comment: 6 pages, 4 Figures, Latex, uses lamuphys.sty, also available at
http://www.mpa-garching.mpg.de/~itziar To appear in the Proceedings of the
ESO/IAC Conference on 'Quasar Hosts' ESO Astrophysics Symposia eds. D.
Clements and I. Perez-Fourno
Two-Stage Multi-Objective Meta-Heuristics for Environmental and Cost-Optimal Energy Refurbishment at District Level
Energy efficiency and environmental performance optimization at the district level are following an upward trend mostly triggered by minimizing the Global Warming Potential (GWP) to 20% by 2020 and 40% by 2030 settled by the European Union (EU) compared with 1990 levels. This paper advances over the state of the art by proposing two novel multi-objective algorithms, named Non-dominated Sorting Genetic Algorithm (NSGA-II) and Multi-Objective Harmony Search (MOHS), aimed at achieving cost-effective energy refurbishment scenarios and allowing at district level the decision-making procedure. This challenge is not trivial since the optimisation process must provide feasible solutions for a simultaneous environmental and economic assessment at district scale taking into consideration highly demanding real-based constraints regarding district and buildings’ specific requirements. Consequently, in this paper, a two-stage optimization methodology is proposed in order to reduce the energy demand and fossil fuel consumption with an affordable investment cost at building level and minimize the total payback time while minimizing the GWP at district level. Aimed at demonstrating the effectiveness of the proposed two-stage multi-objective approaches, this work presents simulation results at two real district case studies in Donostia-San Sebastian (Spain) for which up to a 30% of reduction of GWP at district level is obtained for a Payback Time (PT) of 2–3 years.Part of this work has been developed from results obtained during the H2020 “Optimised Energy
Efficient Design Platform for Refurbishment at District Level” (OptEEmAL) project, Grant No. 680676
How to Detect the Signatures of Self-Gravitating Circumstellar Discs with the Atacama Large Millimetre/sub-millimetre Array
In this paper we present simulated Atacama Large Millimetre/sub-millimetre
Array (ALMA) observations of self-gravitating circumstellar discs with
different properties in size, mass and inclination, located in four of the most
extensively studied and surveyed star-forming regions. Starting from a Smoothed
Particle Hydrodynamics (SPH) simulation and representative dust opacities, we
have initially constructed maps of the expected emission at sub-mm wavelengths
of a large sample of discs with different properties. We have then simulated
realistic observations of discs as they may appear with ALMA using the Common
Astronomy Software Application ALMA simulator. We find that, with a proper
combination of antenna configuration and integration time, the spiral structure
characteristic of self-gravitating discs is readily detectable by ALMA over a
wide range of wavelengths at distances comparable to TW Hydrae (pc), Taurus - Auriga and Ophiucus (pc) star-forming regions.
However, for discs located in Orion complex (pc) only the largest
discs in our sample (outer radius of 100 au) show a spatially resolved
structure while the smaller ones (outer radius of 25 au) are characterized by a
spiral structure that is not conclusively detectable with ALMA.Comment: 12 pages, 10 figure
"Pelas lentes do Cinema. Bioética e Ética em pesquisa". Dirce Guilhem, Debora Diniz, Fabio Zicker (Eds.). Letras Livres, Universidade de Brasília, Brasília 2007, 216 páginas
Corrupción académica en Asia Central
Desde el derrumbe de la Unión Soviética, las cinco repúblicas independientes de Asia Central (Kazajstán, Kirguistán, Tayikistán, Uzbekistán y Turkmenistán) han experimentado profundos cambios socioeconómicos y políticos que han tenido graves repercusiones en el sector de la educación. Pronto se hicieron evidentes las dificultades que comportaba conservar el alto grado de alfabetización y educación heredado del período soviético. La descentralización desorganizada de las estructuras educativas, las limitaciones presupuestarias y la menor implicación estatal que siguieron al derrumbe de la Unión Soviética crearon obstáculos inesperados para los gobiernos de las nuevas repúblicas. Los gobiernos locales se enfrentaron de repente a la difícil tarea de gestionar las instituciones educativas en ámbitos locales, sin recibir el grado necesario de inversión ni de autonomía económica local. Mientras las economías de planificación centralizada de la región prosiguen con su transformación en economías de mercado dinámicas, los sistemas públicos de educación siguen sufriendo las consecuencias negativas del proceso de transición. No se logran adaptar a un nuevo contexto económico que exige nuevas capacidades, la introducción de nuevos modelos educativos y una reforma global efectiva del sistema educativo. El deterioro resultante en la calidad global de la educación y las dificultades a las que se enfrentan actualmente los sistemas de educación superior en la región se deben principalmente a cinco factores clave: la corrupción, los salarios bajos, las oferta insuficiente de personal con formación adecuada, las limitaciones en material y equipamiento y la infraestructura y las instalaciones educativas inapropiadas. Estos factores afectan profundamente a la calidad global de los sistemas educativos de la región.Peer Reviewe
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