Neutrino Mixing: A4A_4 Variations

In the context of the non-Abelian discrete symmetry $A_4$, the neutrino mass matrix has been studied extensively. A brief update is presented to focus on the conceptual shift from tribimaximal mixing ($\theta_{13} = 0$, $\theta_{23} = \pi/4$, $\tan^2 \theta_{12} = 1/2$) to $\underline{\rm cobimaximal}$ mixing ($\theta_{13} \neq 0$, $\theta_{23} = \pi/4$, $\delta_{CP} = \pm \pi/2$) which agrees well with present data. Three specific realistic examples are proposed, two with three and the third with just two parameters.Comment: 9 pages, no figure, version to appear in PL

CP Phases of Neutrino Mixing in a Supersymmetric B-L Gauge Model with T_7 Lepton Flavor Symmetry

In a recently proposed renormalizable model of neutrino mixing using the non-Abelian discrete symmetry T_7 in the context of a supersymmetric extension of the Standard Model with gauged U(1)_{B-L}, a correlation was obtained between \theta_{13} and \theta_{23} in the case where all parameters are real. Here we consider all parameters to be complex, thus allowing for one Dirac CP phase \delta_{CP} and two Majorana CP phases \alpha_{1,2}. We find a slight modification to this correlation as a function of \delta_{CP}. For a given set of input values of \Delta m^2_{21}, \Delta m^2_{32}, \theta_{12}, and \theta_{13}, we obtain \sin^2 2 \theta_{23} and m_{ee} (the effective Majorana neutrino mass in neutrinoless double beta decay) as functions of \tan \delta_{CP}. We find that the structure of this model always yields small |\tan \delta_{CP}|.Comment: 15 pages, 10 figure

Supersymmetric A_4 X Z_3 and A_4 Realizations of Neutrino Tribimaximal Mixing Without and With Corrections

In an improved application of the tetrahedral symmetry A_4 first introduced by Ma and Rajasekaran, supplemented by the discrete symmetry Z_3 as well as supersymmetry, a two-parameter form of the neutrino mass matrix is derived which exhibits the tribimaximal mixing of Harrison, Perkins, and Scott. This form is the same one obtained previously by Altarelli and Feruglio, and the inverse of that obtained by Babu and He. If only A_4 is used, then corrections appear, making tan^2(theta_{12}) differenet from 0.5, without changing significantly sin^2(2 theta_{23}) from one or theta_{13} from zero.Comment: 8 pages, no figur

Common origin of \theta_{13} and \Delta m^2_{12} in a model of neutrino mass with quaternion symmetry

The smallness of the 1-3 lepton mixing angle $\theta_{13}$ and of the neutrino mass-squared-difference ratio $\Delta m^2_{12}/\Delta m^2_{23}$ can be understood as the departure from a common limit where they both vanish. We discuss in general the conditions for realizing the mass degeneracy of a pair of neutrinos and show that the vanishing of a CP violating phase is needed. We find that the discrete quaternion group Q of eight elements is the simplest family symmetry which correlates the smallness of $\Delta m^2_{12}$ to the value of $\theta_{13}$. In such a model we predict $0.12\lesssim \sin\theta_{13} \lesssim 0.2$ if the ordering of the neutrino mass spectrum is normal, and $\sin\theta_{13}\lesssim 0.12$ if it is inverted.Comment: revtex, 7 pages, 6 pdf figures; Appendix added discussing in detail the alignment of VEV

Acceso a la universidad y crisis económica

Durante los últimos años las políticas universitarias han sido tan expansivas e inclusivas como nunca lo habían sido en tiempos anteriores. Sin embargo, la reciente crisis económica parece haber impactado en esta evolución. Para valorar elefecto de la crisis se compara el perfil de las familias de los estudiantes universitarios con las características del conjunto de la población a partir del Censo de 2011, lo que permite estimar el grado de influencia de las condiciones socioeconómicas en el acceso de los estudiantes a los estudios universitarios

Hans Blumenberg: filosofía y la literatura entre 1952 y 1958

From 1952 to 1958 Hans Blumenberg [1920-1996] wrote five philosophical reviews on literature published in the German journal Hochland that have received very little attention by the scholars. This paper focus on Blumenberg’s early reviews devoted to Franz Kafka [1883-1924], Evelyn Waugh [1903-1966], Ernest Hemingway [1899-1961], Thomas S. Eliot [1888- 1965] and William Faulkner [1897-1962].Entre 1952 y 1958 Hans Blumenberg [1920-1996] escribió cinco reseñas literarias, de marcado carácter filosófico, para la revista alemana Hochland. Estas reseñas han recibido muy poca atención por parte de los especialistas interesados en el pensamiento de Blumenberg. En este artículo abordaremos sus análisis tempranos de la obra de Franz Kafka [1883-1924], Evelyn Waugh [1903-1966], Ernest Hemingway [1899-1961], Thomas S. Eliot [1888-1965] y William Faulkner [1897-1962]

La metodologia cooperativa a les classes d'educació física, mitjançant els castells com a eina per millorar l'autoestima en els i les alumnes de Secundària

Curs 2011-2012Director/a: Ernest Baige

Wittgenstein: ¿filósofo ruritano?

Capítulo del libro Wittgenstein, 50 años después donde se discute la interpretación del pensamiento wittgensteiniano articulada por Ernest Gellner y el significado político que aquél puede tener

Land-use and Land-ownership changes in Usoma Village, Kenya

This study attempted to find out how land-use activities and land-ownership patterns have changed since land adjudication in Usoma Village, a peri-urban community on the fringe of Kisumu City. The methods used were photo-observation and geo-tagging based on walkabouts onsite, documentary analysis of maps obtained from the Ministry of Lands, interviews with key authority figures, independent experts and community leaders, and interviews as well as focus-group discussions with community members. In terms of land ownership, it was found that subdivisions of land, both formal and informal, had been common over the period. Land transfers based on compulsory acquisition and investment demand were also common. These transfers occurred both within and outside the formal system. In terms of land use, it was found that subsistence-generating activities like fishing and farming have decreased, while cash-generating activities like sand mining and construction of rental housing have increased. The reasons for these land-use and land-ownership changes were discussed, along with their connections to urbanization processes. It was shown that urbanization in Usoma manifests as a shift from subsistence-sustaining to cash-generating activity, along with trends of population densification, state-led development, and the rise of land as commodity and sand as resource. In summary, it can be said that market forces have promoted speculative urban aspirations without providing sustainable urban livelihoods in Usoma