Magnetoresistance at artificial interfaces in the itinerant SrRuO3 ferromagnet

The magnetoresistance across interfaces in the itinerant ferromagnetic oxide SrRuO3 have been studied. To define appropriately the interfaces, epitaxial thin films have been grown on bicrystalline and laser-patterned SrTiO3 substrates. Comparison is made with results obtained on similar experiments using the double-exchange ferromagnetic oxide La2/3Sr1/3MnO3. It is found that in SrRuO3, interfaces induce a substantial negative magnetoresistance, although no traces of the low-field spin tunneling magnetoresistance are found. We discuss these results on the basis of the distinct degree of spin polarization in ruthenates and manganites and the different nature of the surface magnetic layer formed at interfaces.

Enhanced electron-electron correlations in nanometric epitaxial SrRuO3 epitaxial films

Epitaxial and fully strained SrRuO3 thin films have been grown on SrTiO3(100). At initial stages the growth mode is three-dimensional- (3D-)like, leading to a finger-shaped structure aligned with the substrate steps and that eventually evolves into a 2D step-flow growth. We study the impact that the defect structure associated with this unique growth mode transition has on the electronic properties of the films. Detailed analysis of the transport properties of nanometric films reveals that microstructural disorder promotes a shortening of the carrier mean free path. Remarkably enough, at low temperatures, this results in a reinforcement of quantum corrections to the conductivity as predicted by recent models of disordered, strongly correlated electronic systems. This finding may provide a simple explanation for the commonly observed¿in conducting oxides-resistivity minima at low temperature. Simultaneously, the ferromagnetic transition occurring at about 140 K, becomes broader as film thickness decreases down to nanometric range. The relevance of these results for the understanding of the electronic properties of disordered electronic systems and for the technological applications of SrRuO3¿and other ferromagnetic and metallic oxides¿is stressed.

Magnetic field effect on quantum corrections to the low-temperature conductivity in mettalic perovskite oxides

The transport and magnetotransport properties of the metallic and ferromagnetic SrRuO3 (SRO) and the metallic and paramagnetic LaNiO3 (LNO) epitaxial thin films have been investigated in fields up to 55 T at temperatures down to 1.8 K . At low temperatures both samples display a well-defined resistivity minimum. We argue that this behavior is due to the increasing relevance of quantum corrections to the conductivity (QCC) as temperature is lowered; this effect being particularly relevant in these oxides due to their short mean free path. However, it is not straightforward to discriminate between contributions of weak localization and renormalization of electron-electron interactions to the QCC through temperature dependence alone. We have taken advantage of the distinct effect of a magnetic field on both mechanisms to demonstrate that in ferromagnetic SRO the weak-localization contribution is suppressed by the large internal field leaving only renormalized electron-electron interactions, whereas in the nonmagnetic LNO thin films the weak-localization term is relevant.

Giant step bunching from self-organized coalescence of SrRuO3 islands

Step bunching develops in the epitaxy of SrRuO3 on vicinal SrTiO3(001) substrates. We have investigated the formation mechanisms and we show here that step bunching forms by lateral coalescence of wedgelike three-dimensional islands that are nucleated at substrate steps. After coalescence, wedgelike islands become wider and straighter with growth, forming a self-organized network of parallel step bunches with altitudes exceeding 30 unit cells, separated by atomically flat terraces. The formation mechanism of step bunching in SrRuO3, from nucleated islands, radically differs from one-dimensional models used to describe bunching in semiconducting materials. These results illustrate that growth phenomena of complex oxides can be dramatically different to those in semiconducting or metallic systems.

Pla de regulació dels camins del terme municipal de la Serra de Prades

Proposta de millora de gestió dels camins del municipi de Prades per tal de millorar la connexió a dins del municipi. L’estudi es basa en diferents apartats: inventari dels camins existents, recuperació dels antics camins ara en desús, disseny d’itineraris de natura (per a l’observació de la vegetació i fauna autòctona) i condicionament dels camins existents per permetre el pas de vehicles especials per a l’extinció d’incendis

Alternative ways to estimate change points in multinomial sequences. An application to an authorship attribution problem

The statistical analysis of literary style is the part of stylometry that compares measurable characteristics in a text that are rarely controlled by the author, with those in other texts. When the goal is to settle authorship questions, these characteristics should relate to the author’s style and not to the genre, epoch or editor, and they should be such that their variation between authors is larger than the variation within comparable texts from the same author. For an overview of the literature on stylometry and some of the techniques involved, see for example Mosteller and Wallace (1964, 82), Herdan (1964), Morton (1978), Holmes (1985), Oakes (1998) or Lebart, Salem and Berry (1998). Tirant lo Blanc, a chivalry book, is the main work in catalan literature and it was hailed to be “the best book of its kind in the world” by Cervantes in Don Quixote. Considered by writters like Vargas Llosa or Damaso Alonso to be the first modern novel in Europe, it has been translated several times into Spanish, Italian and French, with modern English translations by Rosenthal (1996) and La Fontaine (1993). The main body of this book was written between 1460 and 1465, but it was not printed until 1490. There is an intense and long lasting debate around its authorship sprouting from its first edition, where its introduction states that the whole book is the work of Martorell (1413?-1468), while at the end it is stated that the last one fourth of the book is by Galba (?-1490), after the death of Martorell. Some of the authors that support the theory of single authorship are Riquer (1990), Chiner (1993) and Badia (1993), while some of those supporting the double authorship are Riquer (1947), Coromines (1956) and Ferrando (1995). For an overview of this debate, see Riquer (1990). Neither of the two candidate authors left any text comparable to the one under study, and therefore discriminant analysis can not be used to help classify chapters by author. By using sample texts encompassing about ten percent of the book, and looking at word length and at the use of 44 conjunctions, prepositions and articles, Ginebra and Cabos (1998) detect heterogeneities that might indicate the existence of two authors. By analyzing the diversity of the vocabulary, Riba and Ginebra (2000) estimates that stylistic boundary to be near chapter 383. Following the lead of the extensive literature, this paper looks into word length, the use of the most frequent words and into the use of vowels in each chapter of the book. Given that the features selected are categorical, that leads to three contingency tables of ordered rows and therefore to three sequences of multinomial observations. Section 2 explores these sequences graphically, observing a clear shift in their distribution. Section 3 describes the problem of the estimation of a suden change-point in those sequences, in the following sections we propose various ways to estimate change-points in multinomial sequences; the method in section 4 involves fitting models for polytomous data, the one in Section 5 fits gamma models onto the sequence of Chi-square distances between each row profiles and the average profile, the one in Section 6 fits models onto the sequence of values taken by the first component of the correspondence analysis as well as onto sequences of other summary measures like the average word length. In Section 7 we fit models onto the marginal binomial sequences to identify the features that distinguish the chapters before and after that boundary. Most methods rely heavily on the use of generalized linear models

Asertividad infantil y su relación con otras variables psicosociofamiliares.

Realizar un estudio epidemiológico de la población infantil de Málaga sobre depresión y variables asociadas, sobre todo de la asertividad, para poder conocer los factores de riesgo asociados a la depresión infantil de modo que se pueda prevenir, contribuyendo así a una mejora de la salud mental. 1070 escolares de ambos sexos entre 9 y 10 años de 24 colegios tanto públicos como privados y elegidos de forma aleatoria, sistemática y por conglomerado. Partiendo de que la asertividad es situacional, se ha estudiado desde distintas situaciones como: variables de personalidad, variables demográficas, variables escolares, relaciones con los padres y otras variables sociofamiliares. Children's Assertive Behavior Scala (CABS); PNID; CDI; CDR 9-R; CBCL y ESDM; cuestionario A-2 de Martorell - una adaptación del CNS -IE-; calificaciones académicas; cuestionario de datos socio-familiares-r (del Barrio 1985). Tratamiento estadístico mediante el programa SPSS con 201 variables, el análisis incluye un análisis descriptivo, se examinaron las relaciones por medio de tablas de contingencia por el procedimiento Crosstabs. Los profesores han resultado ser buenos predictores de la conducta de los niños mientras que los padres han evaluado deficitariamente a sus hijos, lo que abre una puerta a nuevas investigaciones debido a la importancia del contexto familiar para la conducta de los niños. También hay que resaltar que los factores de riesgo en depresión hacen referencia a las variables de personalidad estudiadas, al igual que las variables escolares inciden en el comportamiento de los niños habiendo más depresión en colegios públicos que en privados.

Diferencias conductuales seg??n g??nero en convivencia escolar

Resumen tomado de la publicaci??n

Taller de llengua : rodolins i gloses. 'Taller de lengua. Pareados y glosas'

Se describe una experiencia llevada a cabo en un colegio p??blico de Mallorca. Se trata de favorecer la expresi??n oral, el vocabulario, la actividad mental y valorar la cultura popular como instrumento necesario para ayudar a lograr el uso normalizado de la lengua catalana mediante la construcci??n de balotas y glosas.

Eficàcia i millora del desenvolupament psicomotor, l'autoconcepte i la socialització mitjançant un programa d'activitats físiques. 'Eficacia y mejora del desarrollo psicomotor, el autoconcepto y la socialización mediante un programa de actividades físicas'.

Resumen tomado de la revista

La formació professional de les Illes Balears : anàlisi de la situació actual. 'La formación profesional de las Islas Baleares : análisis de la situación actual'.

Resumen tomado de la publicación

CP Es Puig, una escola solidària.'CP Es Puig, una escuela solidaria'.

Resumen tomado de la publicación

La participació dels municipis en la millora de l'educació. Una proposta : crear un observatori municipal de l'educació. 'La participación de los municipios en la mejora de la educación. Una propuesta : crear un observatorio municipal de la educación'.

Resumen tomado del autor. Incluye gráficas y tablas de datos