
Celebrated Uruguayan writer Mario Benedetti dies (CNN)
Adiós al poeta del compromiso (El Pais, España)
El impacto de un adiós (El Pais, Uruguay)
Morre aos 88 anos o escritor uruguaio Mario Benedetti (FdSP, Brasil)
"Cosmologists are often in error but never in doubt" - - Lev Landau - - - ["Os cosmologos estao frequentemente errados, mas nunca em duvida"]


Astrónomos de la Universidad de Valencia están determinando con precisión el tamaño del disco de acrecimiento que alimenta el agujero negro central de un cuásar. La detección inequívoca de microlensing cromático en el sistema lente gravitatorio Q2237+0305 (también conocido como Cruz de Einstein), recientemente publicada en el Astrophysical Journal, ofrece perspectivas sin precedentes para el estudio de las propiedades físicas de los discos de acrecimiento.
El efecto lente se produce cuando la luz emitida por un objeto distante, la fuente, es desviada por una masa, la lente, ubicada entre el objeto y el observador. En el caso de Q2237+0305 la luz de un cuásar distante es desviada por una galaxia espiral cercana dando lugar a cuatro imágenes del cuásar localizadas alrededor del núcleo galáctico.
Si bien el efecto lente gravitatoria es independiente de la longitud de onda, en muchos casos se observan diferencias de color entre las diferentes imágenes del cuásar. Una de las posibles causas de este efecto de cromaticidad es el microlensing cromático. Cuando una estrella u objeto compacto de una galaxia lente se ``cruza" sobre la imagen de un cuásar ésta sufre una amplificación conocida como microlensing. Esta amplificación depende del tamaño de la fuente, en este caso el disco de acrecimiento del cuásar. Es de esperar que la emisividad del disco de acrecimiento dependa de la temperatura y, por lo tanto, que se observen diferentes amplificaciones a diferentes longitudes de onda. Este efecto se conoce como microlensing cromático y, sin lugar a dudas, es una poderosa herramienta para estudiar la estructura de los discos de acrecimiento.
Un grupo de astrónomos integrado por la doctorando Ana Mosquera, el Prof. José Muñoz, ambos de la Universidad de Valencia, y en colaboración con el Prof. Evencio Mediavilla del Instituto de Astrofísica de Canarias, han detectado microlensing cromático en una de las imágenes de Q2237+0305 utilizando imágenes de excelente calidad obtenidas con el Telescopio Óptico Nórdico (La Palma - España). Este resultado ha permitido realizar un análisis de los posibles escenarios físicos en los cuales dichos efectos puedan ser observables, así como también un estudio preliminar de la dependencia del tamaño del disco de acrecimiento con la longitud de onda a fin de testar los modelos de disco ya existentes. Estos datos, recientemente publicados en The Astrophysical Journal, conjuntamente con nuevas detecciones de microlensing cromático ya existentes permitirán obtener, por primera vez, restricciones muy precisas en el tamaño del disco de acrecimiento.

Physics Reports in Press, Accepted Manuscript, Available online 7 September 2008AbstractThe dynamics of the tossed coin can be described by deterministic equations of motion, but on the other hand it is commonly taken for granted that the toss of a coin is random. A realistic mechanical model of a coin tossing is constructed to examine whether the initial states leading to heads or tails are distributed uniformly in phase space. We give arguments supporting the statement that the outcome of the coin tossing is fully determined by the initial conditions, i.e. no dynamical uncertainties due to the exponential divergence of initial conditions or fractal basins boundaries occur. We point out that although heads and tails boundaries in the initial condition space are smooth, the distance of a typical initial condition from a basin boundary is so small that practically any uncertainty in initial conditions can lead to the uncertainty of the results of tossing.




From Physical Review D personal ads:
Mature paradigm with firm observational support seeks a fundamental theory in which to be embedded. No loop quantum gravity theories, please. Contact alan @ mit.edu.
Elegant theory of everything desires to explore the landscape with a phenomenon in the hope that it will lead to a prediction. Let’s get physical! Contact ed @ ias.edu.

Science, Evolution, and Creationism Committee on Revising Science and Creationism: A View from the National Academy of Sciences, National Academy of Sciences and Institute of Medicine
In the book, Science, Evolution, and Creationism, a group of experts assembled by the National Academy of Sciences and the Institute of Medicine explain the fundamental methods of science, document the overwhelming evidence in support of biological evolution, and evaluate the alternative perspectives offered by advocates of various kinds of creationism, including “intelligent design.” The book explores the many fascinating inquiries being pursued that put the science of evolution to work in preventing and treating human disease, developing new agricultural products, and fostering industrial innovations. The book also presents the scientific and legal reasons for not teaching creationist ideas in public school science classes.
"El primer síntoma de la vejez es que uno empieza a parecerse a su padre" G. García Marquez.My father surely would agree with that.








As mentioned yesterday, I just gave a public lecture about dark energy.Full post here.
I think the lecture went well. As Jamie said in the comments below, it was literally earthshaking.
[...]
Right after the words came out of my mouth, “Dark Energy, it Stinx, but it Rocks!”, the earth started shaking. Yes, indeed, there was a 5.6 magnitude earthquake, just about 25 miles from where I was speaking, right in the middle of my talk.
America has 62 percent of the world's [scientist] stars as residents, primarily because of its research universities which produce them. Migration plays a significant role in some developing countries.[Paper here or here]

"I mean, if the team want to keep him, they keep him, but I'm here as long as they want me," said Hamilton, speaking before winning the Japanese Grand Prix.So now he wants Alonso out of the team!! McLaren is really playing a strange game... In the words of the three times world champion Nelson Piquet,
"I don't know who else would slip in here, but I'd much rather it were Fernando at Ferrari and me at McLaren."
When asked whether it was normal that Hamilton should say he wants Alonso to leave the team, Piquet said: "No, it's not. No driver should behave that way with his teammate, much less when it's a rookie against a world champion."But the best part of the interview with Piquet was the one below :-)
His [Alonso's] objective was to psychologically destabilise Hamilton, as I used to do with (Nigel) Mansell by saying his wife was ugly and he was dumb..."
