Dark Matter and Vector-like Leptons From Gauged Lepton Number

We investigate a simple model where Lepton number is promoted to a local $U(1)_L$ gauge symmetry which is then spontaneously broken, leading to a viable thermal DM candidate and vector-like leptons as a byproduct. The dark matter arises as part of the exotic lepton sector required by the need to satisfy anomaly cancellation and is a Dirac electroweak (mostly) singlet neutrino. It is stabilized by an accidental global symmetry of the renormalizable Lagrangian which is preserved even after the gauged lepton number is spontaneously broken and can annihilate efficiently to give the correct thermal relic abundance. We examine the ability of this model to give a viable DM candidate and discuss both direct and indirect detection implications. We also examine some of the LHC phenomenology of the associated exotic lepton sector and in particular its effects on Higgs decays.Comment: References and a few comments adde

Agenda 21 and the ecological footprint as instruments to achieve a sustainable university

[Resumen] Para frenar el rápido deterioro ambiental, la universidad ha de formar a las nuevas generaciones en un modelo de sostenibilidad integral (solidaridad sincrónica y diacrónica) y, además, contribuir al cambio en los estilos de vida, en los conocimientos y conductas de la sociedad actual. Esto precisa un nuevo marco teórico-metodológico bajo el paradigma de la sostenibilidad que fundamente y concrete las propuestas educativas. Tomando como referencia los principios del desarrollo sostenible y utilizando como «herramientas» la Agenda 21en la Universidad y la Huella Ecológica, hemos desarrollado y puesto en práctica una estrategia metodológica (ecometodología) con el fin de capacitar a nuestro alumnado (profesorado en formación) para actuar con criterios de sustentabilidad, tanto colectiva, como individualmente[Abstract] In order to stop the quick environmental deterioration of the planet, University has to prepare the new generations following a model of integral sustainability (synchronic and diachronic solidarity) and it also has to contribute to a change in lifestyles, in knowledge and behaviours in our society. There is a need for a new theoretical-methodological frame under the paradigm of sustainability to base educational proposals on it and to concretize them. Taking into consideration the principles of Sustainable Development and using the tools of «Agenda 21 in the University» and Ecological Footprint, we have developed and applied a methodological strategy (ecomethodology) to enable ours students (future teachers) to act, collectively and individually, according to the criteria of sustainabilit

Tensor Analysis and Fusion of Multimodal Brain Images

Current high-throughput data acquisition technologies probe dynamical systems with different imaging modalities, generating massive data sets at different spatial and temporal resolutions posing challenging problems in multimodal data fusion. A case in point is the attempt to parse out the brain structures and networks that underpin human cognitive processes by analysis of different neuroimaging modalities (functional MRI, EEG, NIRS etc.). We emphasize that the multimodal, multi-scale nature of neuroimaging data is well reflected by a multi-way (tensor) structure where the underlying processes can be summarized by a relatively small number of components or "atoms". We introduce Markov-Penrose diagrams - an integration of Bayesian DAG and tensor network notation in order to analyze these models. These diagrams not only clarify matrix and tensor EEG and fMRI time/frequency analysis and inverse problems, but also help understand multimodal fusion via Multiway Partial Least Squares and Coupled Matrix-Tensor Factorization. We show here, for the first time, that Granger causal analysis of brain networks is a tensor regression problem, thus allowing the atomic decomposition of brain networks. Analysis of EEG and fMRI recordings shows the potential of the methods and suggests their use in other scientific domains.Comment: 23 pages, 15 figures, submitted to Proceedings of the IEE

La Agenda 21 y la huella ecológica como instrumentos para lograr una universidad sostenible

Para frenar el rápido deterioro ambiental, la universidad ha de formar a las nuevas generaciones en un modelo de sostenibilidad integral (solidaridad sincrónica y diacrónica) y, además, contribuir al cambio en los estilos de vida, en los conocimientos y conductas de la sociedad actual. Esto precisa un nuevo marco teórico-metodológico bajo el paradigma de la sostenibilidad que fundamente y concrete las propuestas educativas. Tomando como referencia los principios del desarrollo sostenible y utilizando como «herramientas» la Agenda 21en la Universidad y la Huella Ecológica, hemos desarrollado y puesto en práctica una estrategia metodológica (ecometodología) con el fin de capacitar a nuestro alumnado (profesorado en formación) para actuar con criterios de sustentabilidad, tanto colectiva, como individualmente.In order to stop the quick environmental deterioration of the planet, University has to prepare the new generations following a model of integral sustainability (synchronic and diachronic solidarity) and it also has to contribute to a change in lifestyles, in knowledge and behaviours in our society. There is a need for a new theoretical-methodological frame under the paradigm of sustainability to base educational proposals on it and to concretize them. Taking into consideration the principles of Sustainable Development and using the tools of «Agenda 21 in the University» and Ecological Footprint, we have developed and applied a methodological strategy (ecomethodology) to enable ours students (future teachers)to act, collectively and individually, according to the criteria of sustainability

Developing sustainable environmental behavior in secondary education students (12-16) Analysis of a didactic strategy

AbstractEven though the concern about the environment has never been so deep in the developing countries, this fact does not translates into behaviours that are environmentally responsible. One of the possible reasons of the gap between attitudes and behaviours is that the generalized interest for the environment lives with a feeling of hopelessness and incapability to turn the interest in actions. Environmental Education (EE) may play a core role in the solution of this problem, if makes them capable to have a “sustainable” behaviour and make decisions in favour of the environment.In this paper we present a investigative didactic methodology, of a constructivist type, that intends to achieve this goal. The results obtained with students of E.S.O. show that it is a good alternative compared to a more traditional methodology

Gene expression rearrangements denoting changes in the biological state

In many situations, the gene expression signature is a unique marker of the biological state. We study the modification of the gene expression distribution function when the biological state of a system experiences a change. This change may be the result of a selective pressure, as in the Long Term Evolution Experiment with E. Coli populations, or the progression to Alzheimer disease in aged brains, or the progression from a normal tissue to the cancer state. The first two cases seem to belong to a class of transitions, where the initial and final states are relatively close to each other, and the distribution function for the differential expressions is short ranged, with a tail of only a few dozens of strongly varying genes. In the latter case, cancer, the initial and final states are far apart and separated by a low-fitness barrier. The distribution function shows a very heavy tail, with thousands of silenced and over-expressed genes. We characterize the biological states by means of their principal component representations, and the expression distribution functions by their maximal and minimal differential expression values and the exponents of the Pareto laws describing the tails

Macroeconomic environment and corporate finance: the role of monetary policy, labour markets and economic uncertainty

The motivation of this dissertation relies, firstly, on analysing the influence of monetary policy on capital structure throughout the business cycle after the financial crisis of 2008, given the major role that central banks (European and England Central Banks mainly) played in the corporate debt overhang that took place before the crisis and the severe financial difficulties that firms faced afterwards. Secondly, this crisis revealed that countries’ labour market affects the resilience of their firms to face adverse situations. Therefore, it is interesting to study how labour market conditions impact the indirect costs of financial distress that affect companies’ flexibility to cope with the environment and, thus, their bankruptcy risk. Finally, the crisis increased the uncertainty and the information gap between economic agents. Our study analyses how economic policy uncertainty -a market imperfection that exacerbates asymmetric information and opportunism- affects the capital structure, and how countries’ institutions and firms’ strategies can act as shields to alleviate these problems.La motivación de esta tesis se basa, en primer lugar, en analizar la influencia de la política monetaria en la estructura de capital a lo largo del ciclo económico en torno a la crisis financiera de 2008, dado el importante papel que desempeñaron los bancos centrales en el sobreendeudamiento empresarial que tuvo lugar antes de la crisis y las graves dificultades financieras que afrontaron las empresas después. En segundo lugar, esta crisis puso de manifiesto que el mercado laboral de los países afecta a la capacidad de resistencia de sus empresas frente a las situaciones adversas. Por lo tanto, es interesante estudiar cómo las condiciones del mercado laboral influyen en los costes indirectos de la deuda, los cuales afectan a la flexibilidad de la empresa para hacer frente al entorno y, por lo tanto, a su riesgo de quiebra. Por último, la crisis aumentó la incertidumbre y la brecha de información entre los agentes económicos. Nuestro estudio analiza cómo la incertidumbre de la política económica -una imperfección del mercado que exacerba la información asimétrica y el oportunismo- afecta a la estructura de capital, y cómo las instituciones de los países y las estrategias de las empresas pueden actuar como escudos para paliar estos problemas.Escuela de DoctoradoDoctorado en Economía de la Empres