891 research outputs found
A Robust Determination of the size of quasar accretion disks using gravitational microlensing
Using microlensing measurements from a sample of 27 image-pairs of 19 lensed
quasars we determine a maximum likelihood estimate for the accretion disk size
of an {{\em}average} quasar of light days at rest
frame \AA\ for microlenses with a mean mass of
. This value, in good agreement with previous results from
smaller samples, is roughly a factor of 5 greater than the predictions of the
standard thin disk model. The individual size estimates for the 19 quasars in
our sample are also in excellent agreement with the results of the joint
maximum likelihood analysis.Comment: 6 pages, 3 figures, submitted to Ap
Astronomical site selection: On the use of satellite data for aerosol content monitoring
The main goal of this work is the analysis of new approaches to the study of
the properties of astronomical sites. In particular, satellite data measuring
aerosols have recently been proposed as a useful technique for site
characterization and searching for new sites to host future very large
telescopes. Nevertheless, these data need to be critically considered and
interpreted in accordance with the spatial resolution and spectroscopic
channels used. In this paper we have explored and retrieved measurements from
satellites with high spatial and temporal resolutions and concentrated on
channels of astronomical interest. The selected datasets are OMI on board the
NASA Aura satellite and MODIS on board the NASA Terra and Aqua satellites. A
comparison of remote sensing and in situ techniques is discussed. As a result,
we find that aerosol data provided by satellites up to now are not reliable
enough for aerosol site characterization, and in situ data are required.Comment: LaTeX2e MN v2.2, 16 pages with 13 figures. Accepted for Mon. Not. R.
Astron. Soc.(2008
Dominios hexagonales formados por una tricapa de la mezcla Acridina-Ăcido esteĂĄrico en la interfase Aire-Agua
Effects of discontinued endurance methods on VO2max in judokas
Este estudio tuvo como objetivo investigar el efecto de dos diferentes planes de entrenamiento de resistencia basados en la metodologĂa discontinua (intermitente e intervĂĄlica), sobre el VO2MĂĄx de atletas Antioqueños de Judo de rendimiento.
Para ello, 21 Judokas de la SelecciĂłn Antioqueña pertenecientes a la categorĂa Senior (20,43±4,18 años), fueron distribuidos aleatoriamente en tres grupos, dos grupos experimentales y un grupo control. Ambos grupos experimentales entrenaron la resistencia durante 4 semanas con 4 estĂmulos por semana, uno de los grupos experimentales basĂł su entrenamiento en el mĂ©todo intervĂĄlico y el otro en el intermitente. Por su parte, el grupo control no realizĂł ningĂșn tipo de entrenamiento de la resistencia.
No se hallaron diferencias significativas entre pretest y postest de ninguno de los grupos ni experimentales ni el de grupo control (p>0,05). Se concluyó que el entrenamiento de la resistencia basado en métodos discontinuos no produjo diferencias significativas en el VO2Måx
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