38 research outputs found
Bimodal chemical evolution of the Galactic disk and the Barium abundance of Cepheids
In order to understand the Barium abundance distribution in the Galactic disk
based on Cepheids, one must first be aware of important effects of the
corotation resonance, situated a little beyond the solar orbit. The thin disk
of the Galaxy is divided in two regions that are separated by a barrier
situated at that radius. Since the gas cannot get across that barrier, the
chemical evolution is independent on the two sides of it. The barrier is caused
by the opposite directions of flows of gas, on the two sides, in addition to a
Cassini-like ring void of HI (caused itself by the flows). A step in the
metallicity gradient developed at corotation, due to the difference in the
average star formation rate on the two sides, and to this lack of communication
between them. In connection with this, a proof that the spiral arms of our
Galaxy are long-lived (a few billion years) is the existence of this step. When
one studies the abundance gradients by means of stars which span a range of
ages, like the Cepheids, one has to take into account that stars, contrary to
the gas, have the possibility of crossing the corotation barrier. A few stars
born on the high metallicity side are seen on the low metallicity one, and
vice-versa. In the present work we re-discuss the data on Barium abundance in
Cepheids as a function of Galactic radius, taking into account the scenario
described above. The [Ba/H] ratio, plotted as a function of Galactic radius,
apparently presents a distribution with two branches in the external region
(beyond corotation). One can re-interpret the data and attribute the upper
branch to the stars that were born on the high metallicity side. The lower
branch, analyzed separately, indicates that the stars born beyond corotation
have a rising Barium metallicity as a function of Galactic radius.Comment: 6 pages, 7 figures, Proceedings of IAU Symposium 29
Isocyanic acid (HNCO) in the Hot Molecular Core G331.512-0.103: Observations and Chemical Modelling
The authors thank the anonymous referee for the useful comments that improved the article. CMC acknowledges the support of CNPq, Conselho Nacional de Desenvolvimento Científico e Tecnológico – Brazil, process number 41714/2016-6. This study was financed in part by the Coordenaçao de Aperfeiçoamento de Pessoal de Níıvel Su-
perior – Brasil (CAPES) – Finance Code 001. LB acknowledges support from CONICYT (Comisión Nacional de Investigació Científica y Tecnolóogica) project Basal AFB-170002. EM acknowledges sup-
port from the Brazilian agencies FAPESP (Fundaçao de Amparo à Pesquisa do Estado de São Paulo, grant 2014/22095-6) and CNPq
(grant 150465/2019-0). MC acknowledges the financial support from the European Union’s Horizon 2020 research and innovation program
under the Marie Skłodowska-Curie grant agreement no 872081;
from the Spanish National Research, Development, and Innovation plan (RDI plan) under the project PID2019-104002GB-C21; the Consejería de Conocimiento, Investigación y Universidad, Junta
de Andalucía and European Regional Development Fund (ERDF),
ref. SOMM17/6105/UGR; the Ministerio de Ciencia, Innovación y Universidades (ref. COOPB20364); and by the Centro de Estudios Avanzados en Física, Matemáticas y Computación (CEAFMC) of
the University of Huelva
Proyecto LLAMA
In this paper we briefly describe a joint scientific and technological effort between Argentina and Brazil, whose first goal is to install and run, in the northwestern part of Argentina, a millimetre and submillimetre observational facility. In the long run, we would like to incorporate this dish to existing ones (ALMA, APEX, ASTE) in the northern extreme of Chile, to be able to carry out, for the first time in Latinamerican soil, very long base- line interferometry at mm/submm wavelengths. We also succintly mention a long term campaign that is under way in order to monitor the transparency of the atmosphere at those wavelengths. The science that can be accom- plished with this instrument, the technology transfer spin-offs related to this project, and the scientific and strategic importance of this project within both the Argentinean and Latinamerican radioastronomy is described.Fil: Arnal, Edmundo Marcelo. 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: Mirabel Miquele, Igor Felix. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Morras, Ricardo. 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: 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: Abraham, Zulema. Universidade de Sao Paulo; BrasilFil: de Gouveira dal Pino, Elisabete M. de. Universidade de Sao Paulo; BrasilFil: Lepine, Jacques. Universidade de Sao Paulo; Brasi
LLAMA Project
LLAMA, acronymum of Long Latin American Millimetre Array, is a joint scientific and technological undertaking of Argentina and Brazil whose main goal is to install and to operate a 12m dish capable of studyingthe Universe at millimetre and sub-millimetre wavelengths.This facility will be erected in the norwestern part of Argentina, some 20 km away from the town of San Antonio de los Cobres (Salta province), at a site located 4830m above sea level. In this presentation we would like to formally introduce this project to the Latin American astronomical community by briefly describing its current status.Besides working as a stand alone instrument (or single dish mode), this radiometer may also become part of a local network of Very Long Baseline Interferometry (VLBI) that may be integrated by existing telescopes like APEX, ASTE, Itapetinga and some of the ALMA dishes. In its way, this VLBI network may be able to increase the resolving power of ALMA by an order of magnitude.The construction phase of this facility is being financed by Ministerio de Ciencia, Tecnología e Innovación Productiva (MINCyT, Argentina) and Fundacao de Amparo á Pesquisa do Estado de Sao Paulo (FAPESP), on the basis of an equal investment share.Fil: Arnal, Edmundo Marcelo. 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: Abraham, Zulema. Universidade do Sao Paulo. Instituto de Astronomia, Geofísica e Ciências Atmosféricas; BrasilFil: Giménez de Castro, Guillermo. Universidade Presbiteriana Mackenzie; BrasilFil: Gouveia dal Pino, E. M. de. Universidade do Sao Paulo. Instituto de Astronomia, Geofísica e Ciências Atmosféricas; BrasilFil: Larrarte, Juan Jose. 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: Lepine, Jacques. Universidade do Sao Paulo. Instituto de Astronomia, Geofísica e Ciências Atmosféricas; BrasilFil: Morras, Ricardo. 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: Viramonte, Jose Maria. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto Geonorte; ArgentinaXIV Latin American Regional IAU meetingFlorianapolisBrasilUniversidade Federal de Santa Catarin
The Long Latin American Millimeter Array: a new submillimeter facility to observe the Sun
The Long Latin American Millimeter Array (LLAMA), is an Argentinian - Brazilian project to build and operate a 12-m radiotelescope that may observe from 45 to 900 GHz and that will have VLBI capabilities. LLAMA will be installed in the Argentinian "Puna de Atacama" region at 4800 m above see level in the Salta Province, at less than 200 km distance from ALMA. The site has excellent sky transmission characteristics for submillimeter astronomy. LLAMA may observein single dish mode, or as VLBI station associated to ALMA at submillimeter wavelengths or to other telescopes at microwaves. Since it is a multipurpose observatory,it has within its objectives,observing the Sun. In VLBI mode it will have a resolution better than 0.001 arcsec at 1 mm wavelength, bringing unprecedented images of the solar atmosphere with a spatial resolution of the order of 1 km. In single dish mode, it will complement spectral observations already carry out by other telescopes. Key aspects to be addressed by solar LLAMA observations are: i) low atmosphere structure, ii) filaments, iii) dynamics of the chromosphere and its magnetic field and iv) flares. The project received full financial support from the Brazilian Agency FAPESP and the Argentinian Ministry of Science for the installation and operation of the antenna near thetown of San Antonio de los Cobres, and should have its first light by beginning 2015, expecting to start early science on middle 2016. We detail in this work the technical features of LLAMA, its state of advance and the science that may be done with its observations.Fil: Giménez de Castro, Guillermo C.. Universidade Presbiteriana Mackenzie; BrasilFil: Abraham, Zulema. Universidade do Sao Paulo. Instituto de Astronomia, Geofísica e Ciências Atmosféricas; BrasilFil: Arnal, Edmundo Marcelo. 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: Gouveia Dal Pino, Elizabete de. Universidade do Sao Paulo. Instituto de Astronomia, Geofísica e Ciências Atmosféricas; BrasilFil: Larrarte, Juan Jose. 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: Lepine, Jacques. Universidade do Sao Paulo. Instituto de Astronomia, Geofísica e Ciências Atmosféricas; BrasilFil: Morras, Ricardo. 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: Viramonte, Jose Maria. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto Geonorte; Argentina2nd Solar ALMA WorkshopPragaRepública ChecaAcademy of Sciences of the Czech Republic. Astronomical Institut
Opto-thermo-mechanical numerical simulations of 3 different concepts of infrared achromatic phase shifters
The Darwin/TPF mission aims at detecting directly extra solar planets. It is based on the nulling interferometry, concept proposed by Bracewell in 1978, and developed since 1995 in several European and American laboratories. One of the key optical devices for this technique is the achromatic phase shifter (APS). This optical component is designed to produce a π phase shift over the whole Darwin spectral range (i.e. 6-18 μm), and will be experimentally tested on the NULLTIMATE consortium nulling test bench (Labèque et al). Three different concepts of APS are being simulated: dispersive plates focus crossing and field reversal. In this paper, we show how thermal, mechanical and optical models are merged into a single robust model, allowing a global numerical simulation of the optical component performances. We show how these simulations help us to optimizing the design and present results of the numerical model
LSST Science Book, Version 2.0
A survey that can cover the sky in optical bands over wide fields to faint
magnitudes with a fast cadence will enable many of the exciting science
opportunities of the next decade. The Large Synoptic Survey Telescope (LSST)
will have an effective aperture of 6.7 meters and an imaging camera with field
of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over
20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with
fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a
total point-source depth of r~27.5. The LSST Science Book describes the basic
parameters of the LSST hardware, software, and observing plans. The book
discusses educational and outreach opportunities, then goes on to describe a
broad range of science that LSST will revolutionize: mapping the inner and
outer Solar System, stellar populations in the Milky Way and nearby galaxies,
the structure of the Milky Way disk and halo and other objects in the Local
Volume, transient and variable objects both at low and high redshift, and the
properties of normal and active galaxies at low and high redshift. It then
turns to far-field cosmological topics, exploring properties of supernovae to
z~1, strong and weak lensing, the large-scale distribution of galaxies and
baryon oscillations, and how these different probes may be combined to
constrain cosmological models and the physics of dark energy.Comment: 596 pages. Also available at full resolution at
http://www.lsst.org/lsst/sciboo
Le gisement sulfo-arsenie aurifere du Cambrien inferieur de la mine traditionnelle de Salsigne (Montagne Noire, France) : contexte structural, metallogenique et sedimentologique
SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc
Abord psychologique de la rétropulsion à début brutal chez les personnes âgées
La rétropulsion à début brutal est un trouble postural spécifique au grand âge dont on a exploré le versant psychique. Avec la rétropulsion, c'est la question de sa propre mort que convoque la personne; à une période qu'elle interprète comme un effondrement psychosocial. La rééducation, qui est le traitement le plus adéquat, est efficace aussi parce que les représentations particulières des kinésithérapeutes leurs permettent de situer le phénomène uniquement dans le champ somatique, et ainsi de sortir le symptôme de son réseau de signification morbide. L'amélioration somatique s'accompagne d'un rétrécissement de l'imaginaire qui correspond à une nécessité pour la personne de mettre à distance les motions inconscientes qui ont été mobilisées lorsque la rétropulsion était présente. La fonction de défense de la rétropulsion se comprend par la réactualisation de mécanismes archaïques, jadis utilisés lorsque s'était constitué la vie intérieure, en péril au moment où survient le trouble postural.Brutal onset retropulsion is a postural disturbance specific to old age, which is studied here in its psychic aspects. Retropulsion provokes questions on their mortality in affected persons, during a period which they interpret as a psycho-social collapse. A rehabilitation programme is the most appropriate and effective treatment because the specialised approach of the Physiotherapist encourages work on a practical physical level, removing the tangle of morbid implications associated with the symptom. The physical improvement progresses alongside a repression of the imagined fears, a repression necessary in order to allow the sufferer to distance themselves from the subconscious motivations activated at the moment of the appearance of the retropulsion. Retropulsion as a defence mechanism can be recognised as an updating of the archaic reactions previously used during the development of the Inner Personality, this entity psychic feeling threatened at the moment of the postural disturbance.LYON2/BRON-BU (690292101) / SudocSudocFranceF