Scalar Field Dark Matter: behavior around black holes

We present the numerical evolution of a massive test scalar fields around a Schwarzschild space-time. We proceed by using hyperboloidal slices that approach future null infinity, which is the boundary of scalar fields, and also demand the slices to penetrate the event horizon of the black hole. This approach allows the scalar field to be accreted by the black hole and to escape toward future null infinity. We track the evolution of the energy density of the scalar field, which determines the rate at which the scalar field is being diluted. We find polynomial decay of the energy density of the scalar field, and use it to estimate the rate of dilution of the field in time. Our findings imply that the energy density of the scalar field decreases even five orders of magnitude in time scales smaller than a year. This implies that if a supermassive black hole is the Schwarzschild solution, then scalar field dark matter would be diluted extremely fastComment: 15 pages, 21 eps figures. Appendix added, accepted for publication in JCA

Análisis de errores conceptuales y concepciones alternativas de mecánica newtoniana en alumnos del tronco general de ciencias básicas de la UAM-Iztapalapa

Se presentan los resultados de una investigación realizada en alumnos del trimestre de otoño 2007 de la UEA de mecánica del primer trimestre del tronco general. Dos grupos recibieron una enseñanza centrada en los conceptos con participación activa de los alumnos, y los otros dos una enseñanza más tradicional. Se incorporó la búsqueda de las ideas previas usando el Force Concept Inventory (FCI) en su versión en castellano y la puesta en marcha de estrategias didácticas específicas. El FCI fue aplicado a principio y a final del trimestre en cada grupo. Se muestra, i) que la clase magistral no funciona, ii) que el uso de cualquier evolución técnica no cambia nada si el alumno no participa, iii) que la implicación de los alumnos es indispensable para un aprendizaje significativo. Se compararon los resultados obtenidos con algunas instituciones de Estados Unidos y Europa

An integrated approach toward the incorporation of clouds in the temperature retrievals from microwave measurements

In this paper, we address the characterization of clouds and its inclusion in microwave retrievals in order to study its effect on tropospheric temperature profiles measured by TEMPERA radiometer. TEMPERA is the first ground-based microwave radiometer that makes it possible to obtain temperature profiles in the troposphere and stratosphere at the same time. In order to characterize the clouds a multi-instrumental approach has been adopted. Cloud base altitudes were detected using ceilometer measurements while the integrated liquid water was measured by TROWARA radiometer. Both instruments are co-located with TEMPERA in Bern (Switzerland). Using this information and a constant Liquid Water Content value inside the cloud a liquid profile is provided to characterize the clouds in the inversion algorithm. Microwave temperature profiles have been obtained incorporating this water liquid profile in the inversion algorithm and also without considering the clouds, in order to assess its effect on the retrievals. The results have been compared with the temperature profiles from radiosondes which are launched twice a day at the aerological station of MeteoSwiss in Payerne (40 km W of Bern). Almost 1 year of data have been analysed and 60 non-precipitating cloud cases were studied. The statistical analysis carried out over all the cases evidenced that temperature retrievals improved in most of the cases when clouds were incorporated in the inversion algorithm

A viability study of social economy companies in the market economic system. A case study of southern Spain

In recent years Social Economy has become more accepted in the current Economic System because capitalist economic system has been shown to be imperfect. In fact, in Spain a Social Economy Law was passed last March, and Andalusia is expected to sign up to the III Pact for Social Economy. Thus, this sector is seen as a possible alternative to the current economic system. This research has attempted to quantify the qualitative components of entrepreneurial ability (innovation, cooperation, functional and productive dependence) in the companies belonging to the Social Economy sector in the territory of Seville and compare them to the traditional entrepreneurial structure from Andalusia through descriptive analysis, to confirm whether this business model based on Social Economy is a viable and a sustainable alternative over time. The results have shown that Social Economic businesses could be a better alternative to the predominant entrepreneurial model

Generation of decoherence-free displaced squeezed states of radiation fields and a squeezed reservoir for atoms in cavity QED

We present a way to engineer an effective anti-Jaynes-Cumming and a Jaynes-Cumming interaction between an atomic system and a single cavity mode and show how to employ it in reservoir engineering processes. To construct the effective Hamiltonian, we analyse considered the interaction of an atomic system in a \{Lambda} configuration, driven by classical fields, with a single cavity mode. With this interaction, we firstly show how to generate a decoherence-free displaced squeezed state for the cavity field. In our scheme, an atomic beam works as a reservoir for the radiation field trapped inside the cavity, as employed recently by S. Pielawa et al. [Phys. Rev. Lett. 98, 240401 (2007)] to generate an Einstein-Podolsky-Rosen entangled radiation state in high-Q resonators. In our scheme, all the atoms have to be prepared in the ground state and, as in the cited article, neither atomic detection nor precise interaction times between the atoms and the cavity mode are required. From this same interaction, we can also generate an ideal squeezed reservoir for atomic systems. For this purpose we have to assume, besides the engineered atom-field interaction, a strong decay of the cavity field (i.e., the cavity decay must be much stronger than the effective atom-field coupling). With this scheme, some interesting effects in the dynamics of an atom in a squeezed reservoir could be tested

Effect of the photoperiod on the glutamate level in the suprachiasmatic nucleus of pregnant and non-pregnant rabbits

[EN] Microdialysis sampling was used to measure the glutamate level (GLU) contained in the suprachiasmatic nucleus (SCN) in 10 pregnant and 10 non-pregnant, subjected to either a 16:8 h light-dark cycle or a 12 h advanced photoperiod. Results revealed that GLU levels were significantly greater in samples taken for 2 h (15 min intervals), ¿60, ¿45 and ¿30 min before parturition (P<0.009, P<0.04, P<0.02), and +45 and +60 min after birth (P<0.009, P<0.05) respectively, in pregnant rabbits subjects to a 16:8 LD photoperiod (with light from 6:00-22:00 h). Parturition in these animals occurred at day 31 of gestation. Pregnant rabbits exposed to 12 h advanced photoperiod showed lower GLU levels in the SCN, and a longer gestation period and parturition process. In non-pregnant rabbits the GLU levels in the SCN were also significantly higher (P<0.009, in all samples) in comparison with rabbits subjected to the 12 h shifted photoperiod. It is possible that the photoperiod may have influenced GLU levels, and consequently, the length of gestation, the number of young and the time of birth. However, further studies involving new biotechnologies and a greater number of animals are needed to confirm these results.Reyes-Guerrero, G.; Vázquez-García, M.; Calderón-Guzmán, D.; Donatti-Albarrán, O.; Guevara-Guzmán, R. (2008). Effect of the photoperiod on the glutamate level in the suprachiasmatic nucleus of pregnant and non-pregnant rabbits. World Rabbit Science. 16(3). doi:10.4995/wrs.2008.62316

Towards a FPGA-controlled deep phase modulation interferometer

Deep phase modulation interferometry was proposed as a method to enhance homodyne interferometers to work over many fringes. In this scheme, a sinusoidal phase modulation is applied in one arm while the demodulation takes place as a post-processing step. In this contribution we report on the development to implement this scheme in a fiber coupled interferometer controlled by means of a FPGA, which includes a LEON3 soft-core processor. The latter acts as a CPU and executes a custom made application to communicate with a host PC. In contrast to usual FPGA-based designs, this implementation allows a real-time fine tuning of the parameters involved in the setup, from the control to the post-processing parameters.Comment: Proceedings of the X LISA Symposium, Gainesville, May 18-23, 201

La formación en economía social. Análisis de la oferta universitaria de posgrado en España

En el presente artículo se analiza la importancia que tiene la formación para el fomento de la economía social, prestando especial atención a la caracterización de la oferta formativa de este tipo de estudios y diferenciándola respecto a la oferta formativa convencional en el área de Administración y Dirección de Empresas, emprendimiento e innovación. Previo a ello, se reflexiona, en base a un breve análisis bibliográfico, sobre las relaciones que se establecen entre educación y economía para, posteriormente, centrarnos en la caracterización de este tipo de formación, prestando especial atención a la que se centra en la Economía Social. Para ello, en primer lugar, se ha elaborado una base de datos en la que se incluyen todas las titulaciones de posgrado relacionadas con los estudios de Economía. Asimismo, se ha diseñado un cuestionario estructurado con el objetivo de caracterizar este tipo de formación. Se concluye la escasa importancia que tiene en el sistema universitario de posgrado español la formación en Economía Social, detectándose algunas diferencias significativas en la caracterización del proceso formativo entre las titulaciones de Economía Social y las convencionales de Administración y Dirección de Empresas, emprendimiento e innovación empresarial, en aspectos tales, como: los valores, las competencias, las habilidades, la forma de entender y transmitir el funcionamiento de la economía, etc. A partir de estas conclusiones se dan una serie de recomendaciones que pueden contribuir a fomentar y dinamizar, mediante la formación en posgrados, la Economía Social