Interplay between the magnetic anisotropy contributions of Cobalt nanowires

We report on the magnetic properties and the crystallographic structure of the cobalt nanowire arrays as a function of their nanoscale dimensions. X-ray diffraction measurements show the appearance of an in-plane HCP-Co phase for nanowires with 50 nm diameter, suggesting a partial reorientation of the magnetocrystalline anisotropy axis along the membrane plane with increasing pore diameter. No significant changes in the magnetic behavior of the nanowire system are observed with decreasing temperature, indicating that the effective magnetoelastic anisotropy does not play a dominant role in the remagnetization processes of individual nanowires. An enhancement of the total magnetic anisotropy is found at room temperature with a decreasing nanowire diameter-to-length ratio (d/L), a result that is quantitatively analyzed on the basis of a simplified shape anisotropy model.Comment: 8 pages, 4 figure

Artefacts in geometric phase analysis of compound materials

The geometric phase analysis (GPA) algorithm is known as a robust and straightforward technique that can be used to measure lattice strains in high resolution transmission electron microscope (TEM) images. It is also attractive for analysis of aberration-corrected scanning TEM (ac-STEM) images that resolve every atom column, since it uses Fourier transforms and does not require real-space peak detection and assignment to appropriate sublattices. Here it is demonstrated that in ac-STEM images of compound materials (i.e. with more than one atom per unit cell) an additional phase is present in the Fourier transform. If the structure changes from one area to another in the image (e.g. across an interface), the change in this additional phase will appear as a strain in conventional GPA, even if there is no lattice strain. Strategies to avoid this pitfall are outlined.Comment: 9 pages, 7 figures, Preprint before review, submitted to Ultramicroscopy 7 April 201

Problem Faced by Digital Evidence in U.S. Law

El presente artículo analiza los problemas que en el derecho de los Estados Unidos de Norteamérica enfrenta la prueba digital. Al no contar con una regulación particular para este tipo de prueba, los jueces han aplicado las normas previstas para las pruebas físicas. Lo anterior si bien ha resultado útil en muchos casos, ha generado más de algún problema que la doctrina de Estados Unidos ha criticado. Desde esta perspectiva se debe tener presente que no todas las reglas y procedimientos previstos para las pruebas físicas, se pueden aplicar sin más a la confiscación de una prueba digital

Cholestasis associated to inborn errors in bile acid synthesis

Several metabolic pathways are involved in the biotransformation of C27 neutral cholesterol to C24 primary bile acids (BAs), mainly cholic acid (CA) and chenodeoxycholic acid (CDCA), which are then conjugated with glycine or taurine. This process can start with the modification of the steroid ring or the shortening of the side chain and involves enzymes present in different subcellular compartments. Inborn errors affecting the biogenesis of organelles, such as peroxisomes, or the expression or function of specific enzymes of these convergent routes result in: i) the lack of mature C24-BAs, with the subsequent impairment in digestion and absorption of dietary fat and liposoluble vitamins, such as vitamin K, which may account for a deficient hepatic synthesis of several coagulation factors; ii) the accumulation of intermediate metabolites, which may affect hepatocyte physiology, causing cholestasis as a commonly shared alteration besides other deleterious hepatic events; and iii) extrahepatic clinical manifestations due to accumulation of toxic metabolites in other territories, such as the nervous system, causing neurological disorders. In general, diseases whose primary alteration is a genetic defect in BA synthesis are diagnosed in children or young individuals with a very low incidence. The symptomatology can markedly vary among individuals, ranging from mild to severe conditions. Oral therapy, based on the enrichment of the BA pool with natural C24-BAs, such as CA, CDCA, glyco-CA, or ursodeoxycholic acid (UDCA), depending on the exact deficiency causing the disease, may be beneficial in preventing life-threatening situations. In contrast, in other cases, a liver transplant is the only option for these patients. This review describes the updated information on the genetic and molecular bases of these diseases and the current approaches to achieve a selective diagnosis and specific treatment

Nivel de estudios y experiencia de las árbitras y árbitras asistentes de fútbol en España: Primera División Femenin

El objetivo de esta investigación fue analizar las características sociodemográficas de las árbitras y árbitras asistentes pertenecientes a la primera división de fútbol femenino en España. La muestra estuvo compuesta por 45 mujeres de nacionalidad española (28.11±4.24 años) y fue dividida en árbitras (n=17) y árbitras asistentes (n=28). Se utilizó un cuestionario ad hoc que contenía 8 ítems y analizaban variables sociales, deportivas y de rendimiento. La muestra se caracteriza por alcanzar una mayor formación universitaria (52.94% en árbitras y 42.86% en árbitras asistentes) y de máster (41.18% y 35.71% respectivamente) frente a Formación Profesional (5.88% en árbitras y 14.29% en árbitras asistentes). Estas, además, mostraron una media de 12.35±6.35 años en el arbitraje de fútbol, mientras que las árbitras asistentes evidenciaron una media de 8.82±4.15 años. En relación a las sesiones de entrenamientos, las árbitras evidenciaron 4-5 sesiones de entrenamiento, mientras que las árbitras asistentes acumularon un total de 4 sesiones a la semana. Las árbitras que participaron en partidos internacionales mostraron una media de 13.77±0.61 años en el arbitraje, mientras que las que no participaron en partidos internacionales tuvieron una media de 8.69±4.12 años. Las árbitras y árbitras asistentes mostraron altos niveles de formación académica universitaria y evidenciaron una corta experiencia en Primera División en Fútbol Femenina. Los resultados muestran la importancia de la experiencia en el desempeño arbitral para alcanzar el máximo nivel en el arbitraje femenino. The objective of this research was to analyze the sociodemographic characteristics of the referees and assistant referees belonging to the first division of women''s football in Spain. The sample consisted of 45 women of Spanish nationality (28.11 +/- 4.24 years) and was divided into referees (n=17) and assistant referees (n=28). An ad hoc questionnaire containing 8 items was used and analyzed social, sports and performance variables. The sample is characterized by reaching higher university training (52.94% in female referees and 42.86% in assistant referees) and master''s degree (41.18% and 35.71% respectively) compared to professional training (5.88% in female referees and 14.29% in assistant referees). They also showed a mean of 12.35 +/- 6.35 years in soccer refereeing, while the assistant referees showed a mean of 8.82 +/- 4.15 years. In relation to the training sessions, the referees showed 4-5 training sessions, while the assistant referees accumulated a total of 4 sessions per week. The female referees who participated in international matches showed a mean of 13.77 +/- 0.61 years in arbitration, while those who did not participate in international matches had an average of 8.69 +/- 4.12 years. The referees and assistant referees showed high levels of university academic training, evidenced a short experience in the First Division in Women''s Soccer. The results show the importance of experience in refereeing performance to reach the highest level in female refereeing

Potential models for the simulation of methane adsorption on graphene: development and CCSD(T) benchmarks

Different force fields for the graphene–CH4 system are proposed including pseudo-atom and full atomistic models. Furthermore, different charge schemes are tested to evaluate the electrostatic interaction for the CH4 dimer. The interaction parameters are optimized by fitting to interaction energies at the DFT level, which were themselves benchmarked against CCSD(T) calculations. The potentials obtained with both the pseudo-atom and full atomistic approaches describe accurately enough the average interaction in the methane dimer as well as in the graphene–methane system. Moreover, the atom–atom potentials also correctly provide the energies associated with different orientations of the molecules. In the atomistic models, charge schemes including small charges allow for the adequate representation of the stability sequence of significant conformations of the methane dimer. Additionally, an intermediate charge of −0.63e on the carbon atom in methane leads to bond energies with errors of ca. 0.07 kcal mol−1 with respect to the CCSD(T) values for the methane dimer. For the graphene–methane interaction, the atom–atom potential model predicts an average interaction energy of 2.89 kcal mol−1, comparable to the experimental interaction energy of 3.00 kcal mol−1. Finally, the presented force fields were used to obtain self-diffusion coefficients that were checked against the experimental value found in the literature. The no-charge and Hirshfeld charge atom–atom models perform extremely well in this respect, while the cheapest potential considered, a pseudo-atom model without charges, still performs reasonably well