Higgsino mass matrix ansatz for MSSM

An ansatz, Det. $M_{\tilde H}=0,$ for the Higgsino mass matrix in string orbifold trinification is suggested toward the minimal supersymmetric standard model(MSSM). Small instanton solutions effective around the GUT scale can fulfil this condition. An argument that the couplings contain a moduli field is given for a dynamical realization of this Higgsino mass matrix ansatz.Comment: 15 pages of LaTeX fil

Not All Incentives Wash Out the Warm Glow: The Case of Blood Donation Revisited

The issue of the nature of the altruism inherent in blood donation and the perverse effects of financial rewards for blood and/or organ donation has been recently revisited in the economic literature with limited consensus. As Titmuss (1970) famously pointed out, providing monetary incentives to blood donors may crowd out blood supply as purely altruistic donors may feel less inclined to donate if a reward is involved - in addition to having the effect of reducing blood quality. In this paper we take a different approach by focusing on the nature of the rewards. That is, we examine how favouring different types of incentives are related to the likelihood of donating blood by exploiting a large sample representative of 15 European countries in 2002. Our results show that donors are less likely to favour monetary rewards for blood donation but are more likely to favour non-monetary ones. This is consistent with the idea that while monetary rewards may crowd out blood donation, non-monetary rewards do not.altruism, blood donation, incentives, nudging, recursive system, warm glow

Lepton masses and mixing angles from heterotic orbifold models

We systematically study the possibility for realizing realistic values of lepton mass ratios and mixing angles by using only renormalizable Yukawa couplings derived from heterotic $Z_6$-I orbifold. We assume one pair of up and down sector Higgs fields. We consider both the Dirac neutrino mass scenario and the seesaw scenario with degenerate right-handed majorana neutrino masses. It is found that realistic values of the charged lepton mass ratios, $m_e/m_\tau$ and $m_\mu/m_\tau$, the neutrino mass squared difference ratio, $\Delta m^2_{31}/\Delta m^2_{21}$, and the lepton mixing angles can be obtained in certain cases.Comment: 22 pages, late

Mass transfer from a fluid flowing through a porous media

A mathematical model is developed for the process of mass transfer from a fluid flowing through a packed column. Mass loss, whether by absorption or adsorption, may be significant. This is appropriate for example when removing contaminants from flue gases. With small mass loss the model reduces to a simpler form which is appropriate to describe the removal of contaminants/pollutants from liquids. A case study is carried out for the removal of CO2 from a gas mixture passing over activated carbon. Using the experimental parameter values it is shown, via non-dimensionalisation, that certain terms may be neglected from the governing equations, resulting in a form which may be solved analytically using a travelling wave substitution. From this all important quantities throughout the column may be described; concentration of gaseous materials, amount of material available for mass transfer, fluid velocity and pressure. Results are verified by comparison with experimental data for the breakthrough curve (the amount of carbon measured at the column outlet). The advantage of the analytical expression over a purely numerical solution is that it can easily be used to optimise the process. In the final section we demonstrate how the model may be further reduced when small amounts of contaminant are removed. The model is shown to exhibit better agreement than established models when compared to experimental data for the removal of amoxicillin and congo red dye from water

Gravitational waves from relativistic rotational core collapse

We present results from simulations of axisymmetric relativistic rotational core collapse. The general relativistic hydrodynamic equations are formulated in flux-conservative form and solved using a high-resolution shock-capturing scheme. The Einstein equations are approximated with a conformally flat 3-metric. We use the quadrupole formula to extract waveforms of the gravitational radiation emitted during the collapse. A comparison of our results with those of Newtonian simulations shows that the wave amplitudes agree within 30%. Surprisingly, in some cases, relativistic effects actually diminish the amplitude of the gravitational wave signal. We further find that the parameter range of models suffering multiple coherent bounces due to centrifugal forces is considerably smaller than in Newtonian simulations.Comment: 4 pages, 3 figure

Las emociones en el deporte : conceptos empleados en un modelo tridimensional

La psicología del deporte utiliza modelos dimensionales para organizar el complejo mundo de las emociones. Este trabajo estudia los conceptos empleados en el modelo de Latinjak (2012), que incorpora la perspectiva temporal a las dimensiones tradicionales de valor y activación en el ámbito deportivo. El objetivo principal del presente estudio fue determinar los conceptos más pertinentes para las ocho emociones principales del modelo. Para ello se realizó una investigación en tres etapas consistentes en (a) encontrar conceptos diferentes para las ocho emociones, (b) escoger el más adecuado en cada caso, y (c) comprobar su esp cificidad. Para cada etapa se empleó una muestra diferente y medidas ajustadas a los objetivos. Los resultados permiten indicar los conceptos que mejor definen las ocho emociones principales señaladas en Latinjak (2012), y aportar evidencias en favor de la perspectiva temporal. Finalmente, se discuten algunas aportaciones teóricas y prácticas y las limitaciones del estudio.Dimensional models are used in sport and exercise psychology to organize the complex world of emotions. This study focused on Latinjak's (2012) model which added time perspective to two traditional dimensions: valence and arousal. The purpose of this study was to determine which concepts would best fit for the eight main emotions described in the model. It was carried out in three steps: (a) finding different concepts for each emotion, (b) choosing the most adequate in each case, and (c) verifying their specificity. Each step used a different sample and appropriate measures to fulfil its purpose. The results of this study showed one concept for each emotion of Latinjak's (2012) model, and offered evidence in favour of the time perspective. Finally, theoretical and practical implications alongside limitations of this study were discussed.A psicologia do desporto utiliza modelos dimensionais para organizar o complexo mundo das emoções. Este trabalho estuda os conceitos utilizados no modelo de Latinjak (2012), que incorpora a perspectiva temporal e as dimensões tradicionais de valor e activação no âmbito desportivo. O objectivo principal do presente estudo foi determinar os conceitos mais pertinentes para as oito principais dimensões do modelo. Para tal, realizou-se uma investigação em três etapas que consistiram em (a) encontrar conceitos diferentes para as oito emoções, (b) escolher o mais adequado em cada caso, e (c) comprovar a sua especificidade. Os resultados permitem identificar os conceitos que melhor definem as oito emoções principais constantes em Latinjak (2012), e fornecer evidências a favor da perspectiva temporal. Finalmente, são discutidas algumas contribuições teóricas e práticas, bem como as limitações do estudo

General-Relativistic MHD for the Numerical Construction of Dynamical Spacetimes

We assemble the equations of general relativistic magnetohydrodynamics (MHD) in 3+1 form. These consist of the complete coupled set of Maxwell equations for the electromagnetic field, Einstein's equations for the gravitational field, and the equations of relativistic MHD for a perfectly conducting ideal gas. The adopted form of the equations is suitable for evolving numerically a relativistic MHD fluid in a dynamical spacetime characterized by a strong gravitational field.Comment: 8 pages; scheduled for March 10 issue of Ap

Spherical collapse of supermassive stars: neutrino emission and gamma-ray bursts

We present the results of numerical simulations of the spherically symmetric gravitational collapse of supermassive stars (SMS). The collapse is studied using a general relativistic hydrodynamics code. The coupled system of Einstein and fluid equations is solved employing observer time coordinates, by foliating the spacetime by means of outgoing null hypersurfaces. The code contains an equation of state which includes effects due to radiation, electrons and baryons, and detailed microphysics to account for electron-positron pairs. In addition energy losses by thermal neutrino emission are included. We are able to follow the collapse of SMS from the onset of instability up to the point of black hole formation. Several SMS with masses in the range $5\times 10^5 M_{\odot}- 10^9 M_{\odot}$ are simulated. In all models an apparent horizon forms initially, enclosing the innermost 25% of the stellar mass. From the computed neutrino luminosities, estimates of the energy deposition by $\nu\bar{\nu}$-annihilation are obtained. Only a small fraction of this energy is deposited near the surface of the star, where, as proposed recently by Fuller & Shi (1998), it could cause the ultrarelativistic flow believed to be responsible for $\gamma$-ray bursts. Our simulations show that for collapsing SMS with masses larger than $5\times 10^5 M_{\odot}$ the energy deposition is at least two orders of magnitude too small to explain the energetics of observed long-duration bursts at cosmological redshifts. In addition, in the absence of rotational effects the energy is deposited in a region containing most of the stellar mass. Therefore relativistic ejection of matter is impossible.Comment: 13 pages, 11 figures, submitted to A&