Yukawa Structure from U(1) Fluxes in F-theory Grand Unification

In F-theory GUT constructions Yukawa couplings necessarily take place at the intersection of three matter curves. For generic geometric configurations this gives rise to problematic Yukawa couplings unable to reproduce the observed hierarchies. We point out that if the U(1)_{B-L}/U(1)_Y flux breaking the SO(10)/SU(5) GUT symmetry is allowed to go through pairs of matter curves with the same GUT representation, the quark/lepton content is redistributed in such a way that all quark and leptons are allowed to have hierarchical Yukawas. This reshuffling of fermions is quite unique and is particularly elegant for the case of three generations and SO(10). Specific local F-theory models with SO(10) or SU(5) living on a del Pezzo surface with appropriate bundles and just the massless content of the MSSM are described. We point out that the smallness of the 3rd generation quark mixing predicted by this scheme (together with gauge coupling unification) could constitute a first hint of an underlying F-theory grand unification.Comment: 31 pages, 3 figures, Latex fil

Lacunarity of the Spatial Distributions of Soil Types in Europe.

Lacunarity as a means of quantifying textural properties of spatial distributions suggests a classification into three main classes of the most abundant soils that cover 92% of Europe. Soils with a well-defined self-similar structure of the linear class are related to widespread spatial patterns that are nondominant but ubiquitous at continental scale. Fractal techniques have been increasingly and successfully applied to identify and describe spatial patterns in natural sciences. However, objects with the same fractal dimension can show very different optical properties because of their spatial arrangement. This work focuses primary attention on the geometrical structure of the geographical patterns of soils in Europe. We made use of the European Soil Database to estimate lacunarity indexes of the most abundant soils that cover 92% of the surface of Europe and investigated textural properties of their spatial distribution. We observed three main classes corresponding to three different patterns that displayed the graphs of lacunarity functions, that is, linear, convex, and mixed. They correspond respectively to homogeneous or self-similar, heterogeneous or clustered and those in which behavior can change at different ranges of scales. Finally, we discuss the pedological implications of that classification

On the need for the use of error-controlled finite element analyses in structural shape optimization processes

This is the peer reviewed version of the following article: Ródenas, J. J., Bugeda, G., Albelda, J. and Oñate, E. (2011), On the need for the use of error-controlled finite element analyses in structural shape optimization processes. Int. J. Numer. Meth. Engng., 87: 1105–1126, which has been published in final form at http://dx.doi.org/10.1002/nme.3155. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.This work analyzes the influence of the discretization error associated with the finite element (FE) analyses of each design configuration proposed by the structural shape optimization algorithms over the behavior of the algorithm. The paper clearly shows that if FE analyses are not accurate enough, the final solution provided by the optimization algorithm will neither be optimal nor satisfy the constraints. The need for the use of adaptive FE analysis techniques in shape optimum design will be shown. The paper proposes the combination of two strategies to reduce the computational cost related to the use of mesh adaptivity in evolutionary optimization algorithms: (a) the use of an algorithm for the mesh generation by projection of the discretization error, which reduces the computational cost associated with the adaptive FE analysis of each geometrical configuration and (b) the successive increase of the required accuracy of the FE analyses in order to obtain a considerable reduction of the computational cost in the early stages of the optimization process.The second author is grateful for the financial support received for the development of this paper through the research project DPI2008-05250 of the Ministerio de Ciencia e Innovacion (Spain).Ródenas, J.; Bugeda Castelltort, G.; Albelda Vitoria, J.; Oñate Ibáñez De Navarra, E. (2011). On the need for the use of error-controlled finite element analyses in structural shape optimization processes. International Journal for Numerical Methods in Engineering. 87(11):1105-1126. https://doi.org/10.1002/nme.3155S11051126871

Sexuality in chronic respiratory failure: coincidences and divergences between patient and primary caregiver

AbstractSexual functioning can be affected by chronic illness in a variety of ways. These problems affect the patient's relationship and the degree of satisfaction with his partner. We conducted a study in order to evaluate the perception of sexual difficulties and changes in communication with patients and their wives. Male chronic obstructive pulmonary disease patients with (COPD) and chronic respiratory failure on long-term oxygen therapy were studied. The evaluation method used has consisted of the individualized administration of a semi-structured interview created for this purpose. This interview was conducted with the patients and their wives. One part of the interview was dedicated to evaluating possible sexual problems and how these problems affect the relationship between the couples. In addition, patients as well as their partners were asked the degree of satisfaction with their partners and the degree of satisfaction with their lives. Forty-nine patients and their spouses have been included in the study. Thirty-three patients (67·3%) showed some type of sexual problem (lack of desire and/or impotence). Sixteen wives (33%) answered affirmatively to the question about whether changes at a communicative level as a consequence of the patient's illness had occurred. In relation to the appearance of sexual changes, 46 (94%) of the wives answered affirmatively. The wives were significantly less satisfied with the relationship than the patients, which was related to communication problems. The group of patients were more satisfied with their partners than with their life, whereas no difference has been observed in the wives with both variables. An important percentage of patients with chronic insufficiency who have sexual difficulties exits. A factor which influences the perception of such problems in a very important way is the degree of affection in the relationship between the couples

Dynamical supersymmetry breaking from unoriented D-brane instantons

We study the non-perturbative dynamics of an unoriented Z_5-quiver theory of GUT kind with gauge group U(5) and chiral matter. At strong coupling the non-perturbative dynamics is described in terms of set of baryon/meson variables satisfying a quantum deformed constraint. We compute the effective superpotential of the theory and show that it admits a line of supersymmetric vacua and a phase where supersymmetry is dynamically broken via gaugino condensation.Comment: 24 pages, 1 figur

Matter wave functions and Yukawa couplings in F-theory Grand Unification

We study the local structure of zero mode wave functions of chiral matter fields in F-theory unification. We solve the differential equations for the zero modes derived from local Higgsing in the 8-dimensional parent action of F-theory 7-branes. The solutions are found as expansions both in powers and derivatives of the magnetic fluxes. Yukawa couplings are given by an overlap integral of the three wave functions involved in the interaction and can be calculated analytically. We provide explicit expressions for these Yukawas to second order both in the flux and derivative expansions and discuss the effect of higher order terms. We explicitly describe the dependence of the couplings on the U(1) charges of the relevant fields, appropriately taking into account their normalization. A hierarchical Yukawa structure is naturally obtained. The application of our results to the understanding of the observed hierarchies of quarks and leptons is discussed.Comment: Latex, 51 pages, 4 figures, typos corrected, note adde

Dos embarazadas de la maqbara de la Calle Herrerías (Tudela, Navarra) (s. IX-XI)

X Congreso Nacional de Paleopatología. Univesidad Autónoma de Madrid, septiembre de 200

Funciones Ejecutivas en Estudiantes con Trastorno Específico del Lenguaje al Comienzo de la Escolarización Básica

Las funciones ejecutivas (FE) constituyen un conjunto de habilidades implicadas en el control y regulación del funcionamiento cognitivo. La relación entre FE y desarrollo del lenguaje es especialmente relevante en la conceptualización de los trastornos lingüísticos. El objetivo del estudio consistía en explorar el uso diferencial de FE en dos grupos: Desarrollo Lingüístico Típico (DLT) y Trastorno Específico del Lenguaje (TEL). Participaron 44 estudiantes (56,82% niños), 22 DLT y 22 TEL, con edades entre 6,00–6,92 años (M=6.17, DT=.19). El factor diagnóstico previo mostró efectos significativos en atención ejecutiva (p<.001, η2 parcial =.77), memoria de trabajo (p<.001, η2 parcial =.67), flexibilidad cognitiva (p<.01, η2 parcial =.15), y planificación (p<.001, η2 parcial =.63). En todos los casos, salvo en flexibilidad cognitiva, el tamaño del efecto fue fuerte. Los resultados avalarían la tesis de no especificidad en TEL y la posible presencia de disfunciones cognitivas generales que subyacen al trastorno. The executive functions (ef) constitute a set of skills involved in the control and regulation of cognitive functioning. The relation between ef and the development of language is especially relevant regarding the conceptualization of linguistic disorders. This study aims to explore the differential use of ef between two groups: Typical Language Development (tld) and Specific Language Impairment (sli). The participants were 44 students (56, 82% boys), 22 tld and 22 sli, with ages between 6, 00-6, 92 years (m=6.17, sd=.19). The previous diagnostic factor showed significant effects in executive attention (p<.001, ¿2 partial =.77), working memory (p<.001, ¿2 partial =.67), cognitive flexibility (p<.01, ¿2 partial =.15), and planning (p< .001, ¿2 partial =.63). In every case, except for cognitive flexibility, the effect was strong. The results would support the thesis of non-specificity in the sli and the possible presence of general cognitive dysfunctions that underlie the disorder

Neutrino Masses, Baryon Asymmetry, Dark Matter and the Moduli Problem : A Complete Framework

Recent developments in string theory have led to "realistic" string compactifications which lead to moduli stabilization while generating a hierarchy between the Electroweak and Planck scales at the same time. However, this seems to suggest a rethink of our standard notions of cosmological evolution after the end of inflation and before the beginning of BBN. We argue that within classes of realistic string compactifications, there generically exists a light modulus with a mass comparable to that of the gravitino which generates a large late-time entropy when it decays. Therefore, all known mechanisms of generating the baryon asymmetry of the Universe in the literature have to take this fact into account. In this work, we find that it is still possible to naturally generate the observed baryon asymmetry of the Universe as well as light left-handed neutrino masses from a period of Affleck-Dine(AD) leptogenesis shortly after the end of inflation, in classes of realistic string constructions with a minimal extension of the MSSM below the unification scale (consisting only of right-handed neutrinos) and satisfying certain microscopic criteria described in the text. The consequences are as follows. The lightest left-handed neutrino is required to be virtually massless. The moduli (gravitino) problem can be naturally solved in this framework both within gravity and gauge mediation. The observed upper bound on the relic abundance constrains the moduli-matter and moduli-gravitino couplings since the DM is produced non-thermally within this framework. Finally, although not a definite prediction, the framework naturally allows a light right-handed neutrino and sneutrinos around the electroweak scale which could have important implications for DM as well as the LHC.Comment: 41 pages, no figures, journal version adde

Exponential-Potential Scalar Field Universes I: The Bianchi I Models

We obtain a general exact solution of the Einstein field equations for the anisotropic Bianchi type I universes filled with an exponential-potential scalar field and study their dynamics. It is shown, in agreement with previous studies, that for a wide range of initial conditions the late-time behaviour of the models is that of a power-law inflating FRW universe. This property, does not hold, in contrast, when some degree of inhomogeneity is introduced, as discussed in our following paper II.Comment: 16 pages, Plain LaTeX, 1 Figure to be sent on request, to appear in Phys. Rev.