Robustness of the magnetoresistance of nanoparticle arrays

Recent work has found that the interplay between spin accumulation and Coulomb blockade in nanoparticle arrays results in peaky I-V and tunneling magnetoresistance (TMR) curves and in huge values of the TMR. We analyze how these effects are influenced by a polarization asymmetry of the electrodes, the dimensionality of the array, the temperature, resistance or charge disorder and long-range interactions. We show that the magnitude and voltage dependence of the TMR does not change with the dimensionality of the array or the presence of junction resistance disorder. A different polarization in the electrodes modifies the peak shape in the I-V and TMR curves but not their order of magnitude. Increasing the temperature or length of the interaction reduces to some extent the size of the peaks, being the reduction due to long-range interactions smaller in longer arrays. Charge disorder should be avoided to observe large TMR values.Comment: 8 pages, 8 figure

Estudio geológico del yacimiento de Fornás (Santiago)

[Resumen] El objetivo de este trabajo ha sido la obtención y la aplicación de los datos geológicos en la prospección minera de un determinado tipo de mineralización de sulfuros. En él se presentan resultados del estudio petrográfico y estructural detallado de un sector reducido del Complejo de Ordenes, situado al E. de Santiago de Compostela. El análisis de los datos obtenidos permite relacionar este tipo de cuerpo mineralizado con fracturas de desgarre tardías de dirección aproximada N140E. son por tanto posteriores a todas las etapas de deformación que producen esquistosidad y/o plegamiento. Probablemente los sulfuros han sido preconcentrados en la migmatización posterior a la fase de deformación F4' Se sugiere finalmente un modelo que explica los hechos observados.[Abstract] The essential scope of this work has been the application of the geological data on mining exploration of a particular kind of sulphide ore bodies, such as the ones of Fornás and Arinteiro. Structural and petrographic results have been carried out through detailed survey of the Fornás area, which constitutes a small part of the Ordenes Complex 1ocated to the E of Santiago de Compostela. Analyses of these data allow to relate these ore bodies to late fractures trendind about N140E, which develop after all deformational events yielding associated foliation and/or folding. The sulphides probably were preconcentrated contemporaneously to the migmatization event occurring after the F4 deformational phase. Finally, the authors suggest a model for the explanation of all the geologícal facts observed in the Fornás are

Aggressive behavior in adolescence as a predictor of personal, family, and school adjustment problems

Background: The goal of the present study was to determine the extent to which aggressive behavior towards peers predicts greater personal, school, and family maladjustment in adolescent aggressors of both sexes. Method: The sample consisted of 1510 Spanish adolescents from 12 to 17 years old, who anonymously and voluntarily completed self-report questionnaires. Results: Binary Logistic regression analysis showed that, regarding personal adjustment, aggressive behavior was significantly associated with high scores in depressive symptomatology, perceived stress and loneliness, and low scores in self-esteem, life satisfaction and empathy, for both sexes. In the school setting, aggressive behavior was related to low scores in academic engagement, friends in the classroom, perception of teacher support, and a positive attitude towards school. At the family level, significant relationships were observed between aggressive behavior and high scores in offensive communication and family conflict, and low scores in open communication with parents, general expressiveness, and family cohesion. Conclusions: In cases of peer violence it is necessary to give urgent attention to all those involved, since maladjustment in aggressors can be predicted in many levels of intervention

Neotectonic deformations in the fluvial relief of the Llanura Sur of Pinar del Río, Cuba

Las investigaciones neotectónicas se enfocan a la determinación de los movimientos tectónicos más recientes de la corteza terrestre y poseen un gran significado en el análisis geomorfológico de la estructura del relieve moderno. En las regiones relativamente llanas no siempre resulta fácil el reconocimiento de evidencias de las deformaciones neotectónicas en el relieve fluvial. Desde el punto de vista metodológico, quedó demostrada la eficiencia del empleo de los métodos geológicos, geomorfológicos y edafológicos, como la evaluación morfométrica del relieve, el análisis de anomalías del drenaje, el estudio de la distribución espacial de los complejos estratigráficos y de los sedimentos aluviales, y la espectrometría del canal de potasio en los mismos. Sus resultados destacaron la existencia de bloques longitudinales de tipo horst y graben, corroborando los resultados geofísicos y de perforaciones, así como la identificación de tres bloques transversales escalonados, de oeste a este, con amplitudes diferenciadas de los desplazamientos verticales del orden de 6 y 10 m. Los bloques centro-orientales (II y III) han experimentado una basculación tectónica sostenida, forzando la migración de la red fluvial en dirección suroeste, como lo evidencia la asimetría de las cuencas hidrográficas y la migración de los ríos en esa dirección. Finalmente, se pudo establecer que los ríos, en la parte axial de la llanura, muestran un patrón regional de inflexión horaria de sus cauces, asociado probablemente a movimientos neotectónicos decizalladura que se manifiestan a lo largo de la dislocación que constituye el límite meridional de la depresión Los Palacios

Montanera fattening average daily gain of Silvela iberian pigs according to growing system

Average daily gain during the montanera fattening period (grazing acorns and grass) of a flock of 84 pure Silvela Iberian pigs is analysed. A group was bred in an intensive system and the other one was bred in an traditional outdoor system. The results show better ADG in pigs from the traditional outdoor system but those confirm that is possible to obtain good performances with pigs from intensive system alter an adaptation to grazing period (0.87±0.02 kg versus 0.59±0.02 kg).Se analiza la ganancia media diaria a lo largo de los dos primeros meses de montanera de un grupo de 84 cerdos Ibéricos puros de la estirpe Silvela pertenecientes a dos grupos de recría diferentes: intensivo en parques y extensivo tradicional. Los resultados indican que se obtienen mejores resultados de ganancia media diaria con el sistema extensivo tradicional pero que es posible obtener buenos resultados con los cerdos procedentes del sistema intensivo, previa adaptación al pastoreo (0,87±0,02 kg versus 0,59±0,02 kg; p<0,001)

Long-Span Wooden Structural Floors with Self-Tensioning System: Performance under Asymmetrical Loads

This study analyzes the performance of wooden structural floors equipped with the self-tensioning system patented by the authors, consisting of a force multiplying mechanism connected to a self-tensioning tendon, which is activated automatically when the load is applied to the structural element. The paper describes the system’s difficulties when the structural floor is subjected to asymmetrical loads. The proposed solution consists of anchoring the tendon by an adhesive connection in the central part of the piece yielding a favorable redistribution of the bending moments and an effective performance in terms of deformations. The comparative study focuses on π-shape cross section pieces with spans of 12 m and 15 m, using sections without prestressing and with initial prestressing and self-tensioning system

Agricultura, alimentación y uso del combustible: aplicación de modelos etnográficos en Arqueobotánica

We present ethnographical infomation particularly from the Jbala region in northern Marocco in order to offer archaeologists and archaeobotanists new data that may help in the questions and hypothesis we address to the archaeological record. We deal with these subjects: 1) the cultivation of einkorn (Triticum monococcum), agrarian practices and processing; 2) Conservation and storage of plant foods; 3) Use of cow dung as fuel, tempering of floors and walls and for recipient making; 4) Fuelwood: use, collection, leaf-foddering residues and woodland conservation.El trabajo etnoarqueológico en Marruecos se realiza en el marco del proyecto: Las primeras comunidades campesinas de la Región Cantábrica. El aporte de la etnoarqueología en Marruecos, financiado por la Fundación Marcelino Botín.Peer reviewe

Spin dynamics in helical molecules with nonlinear interactions

It is widely admitted that the helical conformation of certain chiral molecules may induce a sizable spin selectivity observed in experiments. Spin selectivity arises as a result of the interplay between a helicity-induced spin-orbit coupling (SOC) and electric dipole fields in the molecule. From the theoretical point of view, different phenomena might affect the spin dynamics in helical molecules, such as quantum dephasing, dissipation and the role of metallic contacts. With a few exceptions, previous studies usually neglect the local deformation of the molecule about the carrier, but this assumption seems unrealistic to describe charge transport in molecular systems. We introduce an effective model describing the electron spin dynamics in a deformable helical molecule with weak SOC. We find that the electron-lattice interaction allows the formation of stable solitons such as bright solitons with well defined spin projection onto the molecule axis. We present a thorough study of these bright solitons and analyze their possible impact on the spin dynamics in deformable helical molecules