Enhancement of optical absorption in Ga-chalcopirite-based intermediate-band materials for high efficiency solar cells

We present absorption properties enhancement for two CuGaS2-based intermediate-band materials, as promising compounds for high efficiency, lower-cost photovoltaic devices. Previous band diagrams calculations predicted that these materials present a partially filled localized band within the band gap of the host semiconductor, which would increase the absorption of low-energy photons, creating additional electron–hole pairs respect to a conventional semiconductor. This could ideally result in an increase of the photocurrent of the cell without the fall of the open-circuit voltage. In this paper we show, using density functional methods, the effect of this intermediate band on the optical properties of the derived alloys. We highlight the significant enhancement of the absorption coefficient observed in the most intense range of the solar emission and we study the reflectance and transmittance properties of the materials in order to understand the effect of the thickness of the sample on the optical properties. We compare two different substituents of the Ga atoms in CuGaS2, namely, Ti and Cr atoms, able to form the intermediate-band material, and their interest for photovoltaic applications

Making democratic attitudes work : the effect of institutions on europeans' aspirations and evaluations of democracy

Defence date: 19 May 2018Examining Board: Prof. Hanspeter Kriesi, European University Institute (Supervisor); Prof. Stefan Dahlberg, University of Bergen; Prof. Laura Morales, Sciences Po; Prof. Alexander H. Trechsel, European University Institute (Co-supervisor)This thesis analyses how the institutional context of democracies shapes the way citizens evaluate, and what they do ideally expect, from their democratic systems. Although there is a long tradition in political science studying the institutional causes of democratic attitudes, the literature has been commonly focused on the effects of a small group of institutions on a set of attitudes that tap very ambiguously what the citizens actually feel about their system. From the side of institutions, these have been mainly identified with institutions of political representation—notably, electoral and party systems—while other formal arrangements equally relevant for the citizens, such as the rule of law or the welfare state, have remained fairly overlooked. As for popular attitudes toward democracy, the traditional indicators have sought to tap into individuals’ overall assessments of the system but have not allowed scholars to distinguish between the diverse elements with which citizens may be differently satisfied, or to identify their ideal aspirations about the system. By drawing on an innovative dataset that measures individuals’ democratic aspirations and evaluations in a nuanced way, as well as on a large range of macrolevel data on the performance of democracy, the thesis provides a comprehensive framework to understand how political institutions affect citizens’ aspirations and evaluations of democracy in European countries. The thesis starts by discussing the extent to which the new empirical concepts of aspirations and evaluations are indeed sound and meaningful and can serve to elaborate a fine-grained theory on public attitudinal beliefs about the democratic system. Next, I sketch out the theoretical framework of the thesis, which develops around the multifaceted connections between institutions and democratic aspirations and evaluations within specific dimensions of democracy. The results of the three empirical studies provide positive support for the two main hypothesized effects of the framework: (i) Aspirations work as a cognitive yardstick for how citizens evaluate institutional performance; and (ii) Institutions activate the effect of aspirations on performance evaluations by connecting what citizens expect from their democratic system to what they actually gain. This approach covers thus a gap in the literature on public opinion by acknowledging the socio-psychological process underlying the formation of public attitudes toward democracy. In the conclusions, the thesis discusses how these findings qualify much of what we know about the causes and implications of different degrees of public attachment to democracy, and draws insights into the institutional designs that really contribute to build people’s positive attitudes toward democracy

Estudio clínico y genético en carcinoma basocelular esporádico y asociado a Síndrome de Gorlin

[ES] El carcinoma basocelular (CBC) es el tumor más común en la población caucásica y constituye aproximadamente el 80% de los cánceres cutáneos no melanoma. Existen dos formas fundamentales de presentación: esporádica y asociada a genodermatosis, destacando el siíndrome de gorlin en este último grupo. En la patogenia molecular del carcinoma basocelular destacan las mutaciones en el gen PTCH1, que se encuentra involucrado en la vía de señalización sonic hedhehog. El objetivo de esta tesis doctoral es analizar las características clínicas y moleculares pacientes con carcinomas basocelulares esporádicos y con síndrome de Gorlin y de los tumores que desarrollan estos enfermos. Para llevar a cabo este proyecto se obtienen muestras de sangre periférica y de tumor de cada paciente para el estudio genético. Las muestras se procesan y se obtiene en ADN, que posteriormente se analiza. Primeramente se realiza estudio del gen PTCH1 mediante PCR y secuenciación directa. Posteriormente, se efectúa un estudio con CGH-array en las muestras tumorales, para identificar posibles regiones cromosómicas alteradas además de la región en la que está mapeada PTCH1. Se obtienen datos clínicos a partir de las historias clínicas de los pacientes y se revisan las muestras histológicas de los tumores. Se indentifican mutaciones patogénicas en PTCH1 con una frecuencia similar a la publicada en la literatura médica. Además, se localizan varias regiones cromsómicas alteradas con alta frecuencia en los dos tipos de pacientes

Extracción y caracterización de polisacáridos y estudio del perfil de compuestos volátiles en hongos comestibles

En esta tesis se realizó la extracción y caracterización de polisacáridos de cuatro especies de hongos comestibles (boletus edulis, lactarius deliciosus, cantharellus cibarius y calocybe gambosa). En función del tipo de extracción y de la especie de hongo analizada se obtuvieron diferentes polisacáridos: glucanos, glucomananos y un complejo polisacárido-proteína, todos ellos ramificados y con diferentes tamaños moleculares. En su mayoría presentaron conformación terciaria en triple hélice. También se estudió el perfil de compuestos orgánicos volátiles (covs) de seis especies de hongos comestibles (boletus edulis, lactarius deliciosus, calocybe gambosa, hygrophorus marzuolus, cantharellus cibarius y pleurotus ostreatus). Se identificaron un total de 46 compuestos (alcoholes, cetonas y aldehídos, entre otros). Este perfil varió enormemente de una especie de hongo a otra. Igualmente varió significativamente tras el proceso de liofilización, detectándose un aumento en la proporción de aldehídos y una disminución en el contenido de alcoholes, cetonas y compuestos heterocíclicos.Departamento de Biología Celular, Histología y Farmacologí

Consumo de sustâncias psicoativas nos contextos recreativos entre estudantes universitários na Colômbia

El consumo de sustancias psicoactivas (SPA) representa un problema de salud pública en Colombia y en el mundo. La población que recurre a este tipo de sustancias es cada vez más joven y sus efectos son potencialmente deletéreos y pueden afectar todas las áreas de ajuste de la persona. Aunque así se ha concebido, esta práctica no siempre está asociada con problemas personales ni con altos grados de estrés. Puede haber otras motivaciones asociadas. Objetivos: los objetivos de este artículo están dirigidos a presentar: (a) la frecuencia relativa de consumo de SPA entre los estudiantes universitarios, (b) las SPA más utilizadas por los estudiantes universitarios y sus diferencias según el sexo y la edad, (c) la relación entre el uso de SPA y los contextos de diversión. Materiales y métodos: este fue un estudio descriptivo correlacional, derivado de un proyecto de investigación italiano, con una muestra de 226 estudiantes de cuatro carreras de una universidad privada de Bogotá, seleccionados por muestreo aleatorio estratificado con asignación proporcional, a quienes se les aplicó una encuesta. Resultados: las SPA de mayor utilización son el alcohol, la nicotina y la marihuana, cuya mayor predominancia se presenta en el sexo masculino. Los resultados son congruentes con la tendencia nacional. Conclusión: el consumo de SPA en la población universitaria es alto y algunos contextos recreativos están asociados con esta conducta.The consumption of psychoactive substances (PAS) is a public health problem in Colombia and worldwide. The people who consume such substances are becoming younger, and their effects are potentially harmful and may affect all areas of adjustment of the individual. Although it has been conceived that way, the use of PAS is not always associated with personal problems or high degrees of stress. There may be other motivations associated. Objective: The objectives of this article are to present: (a) the relative frequency of consumption of PAS among college students, (b) which are the PAS consumed most by college students and differences in their consumption by sex and by age, (3) the relationship between the consumption of PAS and contexts of diversion. Materials and methods: This is a descriptive correlational study derived from an Italian research project, in which the sample were 226 college students from four undergraduate programs of a private university in Bogotá DC, selected using a stratified random sampling procedure with proportional allocation. Participants filled out a questionnaire. Results: The PAS with the highest consumption were alcohol, nicotine and marijuana. Males predominantly showed an increased consumption. The results are consistent with the national trend. Conclusion: The consumption of SPA among college students is high and some recreational contexts are closely associated with this behaviour.Introdução: o consumo de sustâncias psicoativas (SPA) representa um problema de saúde pública na Colômbia e no mundo. A população que recorre a este tipo de sustâncias é cada vez mais jovem e seus efeitos são potencialmente deletérios e podem afetar todas as áreas de ajuste da pessoa. Mesmo que assim tenha se concebido, esta prática não sempre esta associada com problemas pessoais nem com altos graus de estresse; pode ter outras motivações associadas. Objetivos: os objetivos deste artigo estão dirigidos a apresentar: (a) a frequência relativa de consumo de SPA entre os estudantes universitários, (b) as SPA mais utilizadas pelos estudantes universitários e suas diferenças segundo gênero e a idade, (c) a relação entre o uso de SPA e os contextos de diversão. Materiais e métodos: este foi um estudo descritivo correlacional, derivado de um projeto de pesquisa italiano, com uma amostra de 226 estudantes de quatro cursos de uma universidade privada de Bogotá, selecionados por amostragem aleatória estratificado com designação proporcional. Resultados: as SPA de maior utilização são o álcool, a nicotina y a maconha, cuja maior predominância se apresenta no gênero masculino. Os resultados são congruentes com a tendência nacional. Conclusões: o consumo de SPA na população universitária é alto e alguns contextos recreativos estão associados com esta conduta

Electronic structure and optical properties in ZnO:M(Co, Cd). Effect of band-gap variation

ZnO doped with some transitions metals (ZnO:M) has several significant potential application. ZnO:Co is proposed to be used in advanced spintronic devices due to its high Curie temperature and large magnetic moments per transition metal. ZnO:Cd has potential applications in short-wavelength optoelectronic devices. This work focuses on an ab-initio study of the electronic and optical properties of ZnO:M doped with Co, and Cd. Theoretical calculations have been done with different computational codes, using the density functional theory (DFT) at the GGA and GGA+U level. The latter introduces a Hubbard term correction in the “d” levels of the Zn and Co. We used different supercells in order to have different realistic dilution levels which can be achieved in experiments. Doping effects on the features of the optical absorption are also studied and analysed in this work

Síndrome de Gorlin

[ES]El síndrome de Gorlin es una enfermedad infrecuente de herencia autosómica dominante producida por mutaciones en genes de la vía de señalización Sonic Hedgehog, entre los que destaca PTCH1. Se caracteriza por el desarrollo de múltiples carcinomas basocelulares en edades tempranas, que pueden ir asociados a otras manifestaciones cutáneas como pits palmoplantares, o a manifestaciones extracutáneas, entre las que destacan los queratoquistes odontogénicos y el meduloblastoma. El papel del dermatólogo es importante en la sospecha de este síndrome, pero suele ser necesario un equipo multidisciplinar en el diagnóstico, seguimiento y en el tratamiento de estos pacientes. El tratamiento dermatológico puede ser complicado debido al alto número de carcinomas basocelulares y a su extensión. En los últimos años se han desarrollado nuevos fármacos que inhiben la vía Sonic Hedgehog y parecen prometedores para estos pacientes, aunque su eficacia está limitada por los efectos secundarios y la creación de resistencias.[EN]Gorlin syndrome is a rare autosomal dominant disease caused by mutations in the sonic hedgehog signaling pathway. Of particular importance is the PTCH1 gene. The disease is characterized by the development of multiple basal cell carcinomas at young ages. These tumors may present with other skin manifestations such as palmoplantar pits and with extracutaneous manifestations such as odontogenic keratocysts and medulloblastoma. Although the dermatologist may be key for recognizing clinical suspicion of the syndrome, a multidisciplinary team is usually necessary for diagnosis, treatment, and follow-up. Skin treatment may be complicated due to the large number of basal cell carcinomas and the extent of involvement

The effect of a foreign language on cognitive reappraisal during exposure to a phobic stimulus

This study investigates whether the cognitive reappraisal strategy is influenced by the participant's language (native/foreign) when confronting a fearful stimulus. Sixty participants with subclinical phobia of cockroaches were exposed to several phobic and neutral pictures while they used cognitive reappraisal in their native language or a foreign one. Electrodermal activity, pupil dilation, and self-reports of affective valence and arousal were collected. Results showed that participants in the foreign context were more effective at using reappraisal to reduce valence self-ratings compared to using no regulation. Also, participants in the foreign context showed greater pupil size when reappraising their emotions, compared to the non-regulation condition. Depending on the language, no differences were found for arousal self-reports or electrodermal activity when using reappraisal. These results suggest that using a foreign language could be advantageous in reducing the negative valence through reappraisal. Psychophysiological results are discussed in light of cognitive effort studies.Funding for open access charge: CRUE-Universitat Jaume

La risa que pellizca la realidad

Perdiendo el norte (2015), tercer largometraje de Nacho G. Velilla, tematiza a través de un filtro cómico, la migración a raíz de la crisis financiera española y el difícil proceso de adaptación a las nuevas culturas anfitrionas, logrando en el espectador la risa y la reflexión sobre un fenómeno lamentablemente imperante.</p