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Search Results: 1 - 10 of 26263 matches for " Martin Heida "
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Asymptotic Expansion for Multiscale Problems on Non-periodic Stochastic Geometries
Martin Heida
Physics , 2011,
Abstract: The asymptotic expansion method is generalized from the periodic setting to stationary ergodic stochastic geometries. This will demonstrate that results from periodic asymptotic expansion also apply to non-periodic structures of a certain class. In particular, the article adresses non-mathematicians who are familiar with asymptotic expansion and aims at introducing them to stochastic homogenization in a simple way. The basic ideas of the generalization can be formulated in simple terms, which is basically due to recent advances in mathematical stochastic homogenization. After a short and formal introduction of stochastic geometry, calculations in the stochastic case will be formulated in a way that they will not look different from the periodic setting. To demonstrate that, the method will be applied to diffusion with and without microscopic nonlinear boundary conditions and to porous media flow. Some examples of stochastic geometries will be given.
Large deviation principle for a stochastic Allen-Cahn equation
Martin Heida,Matthias R?ger
Mathematics , 2015,
Abstract: In this paper we consider the Allen-Cahn equation perturbed by a stochastic flux term and prove a large deviation principle. Using an associated stochastic flow of diffeomorphisms the equation can be transformed to a parabolic partial differential equation with random coefficients. We use this structure and first provide a large deviation principle for stochastic flows in function spaces with H\"older-continuity in time. Second, we use a continuity argument and deduce a large deviation principle for the stochastic Allen-Cahn equation.
Discovery of a second outbursting hyperluminous X-ray source
M. Heida,P. G. Jonker,M. A. P. Torres
Physics , 2015, DOI: 10.1093/mnrasl/slv121
Abstract: We report on six Chandra and one HST/WFC3 observation of CXO J122518.6+144545, discovered by Jonker et al. (2010) as a candidate hyperluminous X-ray source (HLX), X-ray bright supernova or recoiling supermassive black hole at $L_X = 2.2 \times 10^{41}$ erg/s (if associated with the galaxy at 182 Mpc). We detect a new outburst of the source in a Chandra image obtained on Nov 20, 2014 and show that the X-ray count rate varies by a factor $> 60$. New HST/WFC3 observations obtained in 2014 show that the optical counterpart is still visible at $g' = 27.1 \pm 0.1$, $1 \pm 0.1$ magnitude fainter than in the discovery HST/ACS observation from 2003. This optical variability strongly suggests that the optical and X-ray source are related. Furthermore, these properties strongly favour an HLX nature of the source over the alternative scenarios. We therefore conclude that CXO J122518.6+144545 is most likely an outbursting HLX. It is only the second such object to be discovered, after HLX-1 in ESO 243-49. Its high X-ray luminosity makes it a strong candidate to host an intermediate mass black hole.
La calidad de vida en los adultos mayores
Montanet Avenda?o,Adalberto; Bravo Cruz,Carmen María; Hernández Elías,Esperanza Heida;
Revista de Ciencias M??dicas de Pinar del R?-o , 2009,
Abstract: a descriptive, cross-sectional study was carried out aimed at assessing the quality of life in the aged taking into consideration different socio-demographic variables emphasizing on the inclusion of this population in the "casa de abuelos" (grandparents' house), during the period january-december 2006. a sample of 42 aged attending to "casa de abuelos" and another one of 42 who did not attend to this place. a structured interview was applied to each aged assessed and the variable quality of life was measured using the m.g.h scale. male sex, ages between 75 -84, single and widowers prevailed. standing out the high and middle categories when measuring the quality of life among the aged; health variable did not change the quality of life in the aged, but satisfaction for life affected a group of them.
La calidad de vida en los adultos mayores Quality of life in the Aged
Adalberto Montanet Avenda?o,Carmen María Bravo Cruz,Esperanza Heida Hernández Elías
Revista de Ciencias M??dicas de Pinar del R?-o , 2009,
Abstract: Se realizó un estudio descriptivo transversal evaluando la Calidad de Vida en adultos mayores, respecto a diferentes variables sociodemográficas, enfatizando en su vinculación a Casa de Abuelos, durante el período de enero- diciembre 2006. Se toma una muestra de 42 ancianos incorporados a la Casa de Abuelos y otra de igual tama o de ancianos no incorporados. A cada anciano evaluado se le aplica una entrevista estructurada y la variable Calidad de Vida se mide con la Escala M.G.H. Se encontró un predominio del sexo masculino, edades de 75-84 a os, solteros y viudos. Sobresalen las categorías alta y media de Calidad de Vida entre los ancianos; la dimensión salud no da a la calidad de vida de los ancianos pero la dimensión satisfacción por la vida si la afecta en un grupo de ellos. A descriptive, cross-sectional study was carried out aimed at assessing the quality of life in the Aged taking into consideration different socio-demographic variables emphasizing on the inclusion of this population in the "Casa de Abuelos" (Grandparents' House), during the period January-December 2006. A sample of 42 aged attending to "Casa de Abuelos" and another one of 42 who did not attend to this place. A structured interview was applied to each aged assessed and the variable Quality of Life was measured using the M.G.H scale. Male sex, ages between 75 -84, single and widowers prevailed. Standing out the high and middle categories when measuring the Quality of Life among the aged; health variable did not change the quality of life in the aged, but satisfaction for life affected a group of them.
A bright off-nuclear X-ray source: A bright off-nuclear X-ray source: a type IIn supernova, a bright ULX or a recoiling super-massive black hole in CXO J122518.6+144545
P. G. Jonker,M. A. P. Torres,A. C. Fabian,M. Heida,G. Miniutti,D. Pooley
Physics , 2010, DOI: 10.1111/j.1365-2966.2010.16943.x
Abstract: In this Paper we report the discovery of CXO J122518.6+144545; a peculiar X-ray source with a position 3.6+-0.2",off-nuclear from an SDSS DR7 z=0.0447 galaxy. The 3.6" offset corresponds to 3.2 kpc at the distance of the galaxy. The 0.3-8 keV X-ray flux of this source is 5x10^-14 erg cm^-2 s^-1 and its 0.3-8 keV luminosity is 2.2x10^41 erg/s (2.7x10^41 erg/s; 0.5-10 keV) assuming the source belongs to the associated galaxy. We find a candidate optical counterpart in archival HST/ACS g'-band observations of the field containing the galaxy obtained on June 16, 2003. The observed magnitude of g'=26.4+-0.1 corresponds to an absolute magnitude of -10.1. We discuss the possible nature of the X-ray source and its associated candidate optical counterpart and conclude that the source is either a very blue type IIn supernova, a ULX with a very bright optical counterpart or a recoiling super-massive black hole.
Accurate positions for the ULXs NGC 7319-X4 and NGC 5474-X1 and limiting magnitudes for their optical counterparts
M. Heida,P. G. Jonker,M. A. P. Torres,S. Mineo
Physics , 2012, DOI: 10.1111/j.1365-2966.2012.21370.x
Abstract: In this paper we report accurate Chandra positions for two ultraluminous X-ray sources: NGC 7319-X4 at Right Ascension (RA) = 339.02917(2) deg, Declination (Dec) = 33.97476(2) deg and NGC 5474-X1 at RA = 211.24859(3) deg, Dec = 53.63584(3) deg. We perform bore-sight corrections on the Chandra X-ray Satellite observations of these sources to get to these accurate positions of the X-ray sources and match these positions with archival optical data from the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope. We do not find the optical counterparts: the limiting absolute magnitudes of the observations in the WFPC2 standard magnitude system are B = -7.9, V = -8.7 and I = -9.3 for NGC 7319-X4 and U = -6.4 for NGC 5474-X1. We report on the X-ray spectral properties and we find evidence for X-ray variability in NGC 5474-X1. Finally, we briefly discuss several options for the nature of these ULXs.
Valoración del dise?o del programa de la asignatura psiquiatría en la carrera de medicina
Hernández Elías,Esperanza Heida; Montanet Avenda?o,Adalberto; Marín Hernández,Dayand; Marín Ortega,Andrés;
Revista de Ciencias M??dicas de Pinar del R?-o , 2007,
Abstract: an analysis of the study program in the psychiatry subject is carried out in medical students teaching this subject in the ninth or tenth semester of this major during 190 hours (six weeks, uninterruptedly). the analysis revealed the absence in the objectives of the community approach which this program must have ,because we are training a professional for working in the community, as well as the need of changes in this program, because there are themes which should be eliminated from the program and to have this time in other themes. it is very important for the basic comprehensive doctor to have a vast knowledge on the following themes : drug-abuse and psychiatric emergencies, especially the prevention of suicidal behaviour. so modifications are proposed as well as the ways which must be used for teaching this themes.
Valoración del dise o del programa de la asignatura psiquiatría en la carrera de medicina Assessment of the Program Design in the Psychiatry Subject in the Medical Major
Esperanza Heida Hernández Elías,Adalberto Montanet Avenda?o,Dayand Marín Hernández,Andrés Marín Ortega
Revista de Ciencias M??dicas de Pinar del R?-o , 2007,
Abstract: Se realiza un análisis del programa de estudio de la asignatura Psiquiatría, en la carrera de medicina, que se imparte en el noveno o décimo semestre de dicha carrera, en un tiempo de 190 horas distribuidas en un período de seis semanas a tiempo completo. Se destacó en el análisis, la carencia en los objetivos del enfoque comunitario que debe tener este programa, si estamos formando un profesional, que desarrollará su trabajo en la comunidad, así como también las necesidades de cambio a realizar en el programa, pues existen temas que deben ser eliminados del programa y utilizarse ese tiempo en otras temáticas. Es de vital importancia que el Médico General Básico posea un amplio conocimiento de temas tales como drogodependencias y urgencias psiquiátricas y dentro de estas últimas en especial la prevención de la conducta suicida, por lo que se hacen las propuestas de modificaciones, así como las formas que deben utilizarse para impartir las mismas. An analysis of the study program in the Psychiatry Subject is carried out in medical students teaching this subject in the ninth or tenth semester of this major during 190 hours (six weeks, uninterruptedly). The analysis revealed the absence in the objectives of the community approach which this program must have ,because we are training a professional for working in the community, as well as the need of changes in this program, because there are themes which should be eliminated from the program and to have this time in other themes. It is very important for the basic comprehensive doctor to have a vast knowledge on the following themes : drug-abuse and psychiatric emergencies, especially the prevention of suicidal behaviour. so modifications are proposed as well as the ways which must be used for teaching this themes.
VLT/FORS2 observations of four high-luminosity ULX candidates
M. Heida,P. G. Jonker,M. A. P. Torres,T. P. Roberts,G. Miniutti,A. C. Fabian,E. M. Ratti
Physics , 2013, DOI: 10.1093/mnras/stt756
Abstract: We obtained VLT/FORS2 spectra of the optical counterparts of four high-luminosity (L_X >= 10^40 erg/s) ULX candidates from the catalog of Walton (2011). We first determined accurate positions for the X-ray sources from archival Chandra observations and identified counterparts in archival optical observations that are sufficiently bright for spectroscopy with an 8 meter telescope. From the spectra we determine the redshifts to the optical counterparts and emission line ratios. One of the candidate ULXs, in the spiral galaxy ESO 306-003, appears to be a bona fide ULX in an HII region. The other three sources, near the elliptical galaxies NGC 533 and NGC 741 and in the ring galaxy AM 0644-741, turn out to be background AGN with redshifts of 1.85, 0.88 or 1.75 and 1.40 respectively. Our findings confirm the trend of a high probability of finding background AGN for systems with a ratio of log(F_X/F_opt) in the range of -1 to 1.
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