Percolative behavior of an anisotropic two-dimensional network: Growth of tellurium onto an oriented polymer film

6 págs.; 9 figs.In situ transport measurements during the growth of a thin layer of thermally evaporated tellurium onto an oriented polymer film are presented. The system, which resembles the characteristics of a two-dimensional anisotropic network, is analyzed in terms of the current percolation theory. Parameters such as the percolation threshold and the critical exponents are calculated for the perpendicular and the parallel orientation. Within the limits of the experiments the values of t∥ and t⊥ are estimated to be 1.15 and 1.46, respectively. ©1997 American Physical SocietyFinancial support by the Volkswagen Foundation and Comision Interministrial de Ciencia y Tecnologia (Grant No. MAT94-0825) are gratefully acknowledged.Peer Reviewe

Stereometry of Crystalline Phases Observed in Scanning Electron Microscopy

A study of edges and angles of known samples has been performed by means of stereoscopic pairs with electron microscopy in two and three dimensional systems. The derived equations have been included in a computer program. Measurements on stereoscopic pairs with different tilt angles using several crystals of galena, calcite and other objects with known dimensions have been performed. The optimum tilt angles have been obtained by comparison with the actual values, and a logarithmic ratio between these angles and the stereoscopic pairs magnification has been found. The errors obtained using this system of calculation are lower than 6% in the measure of angles and 15% in the case of edges

su(1,1) Algebraic approach of the Dirac equation with Coulomb-type scalar and vector potentials in D + 1 dimensions

We study the Dirac equation with Coulomb-type vector and scalar potentials in D + 1 dimensions from an su(1, 1) algebraic approach. The generators of this algebra are constructed by using the Schr\"odinger factorization. The theory of unitary representations for the su(1, 1) Lie algebra allows us to obtain the energy spectrum and the supersymmetric ground state. For the cases where there exists either scalar or vector potential our results are reduced to those obtained by analytical techniques

Effects of basic infrastructure on ENLACE Test of High School Technology Mexican

Bajo la teoría de capital humano, la educación se concibe como auspiciadora de capital humano y económico. La inversión en capital humano puede reflejarse a mediano plazo en el logro académico de los estudiantes. El logro académico es un indicador de la eficacia de las políticas educativas, sin embargo, en Latino América hay pocos estudios que analicen los efectos que tienen los insumos o el gasto de inversión en el desempeño de los estudiantes. En el presente estudio se analizó una muestra de 538 escuelas de educación media superior con el fin de evaluar los efectos que tiene el número de alumnos por grupo y el número de alumnos por clase sobre el logro académico. Se realizó análisis factorial confirmatorio y un modelo estandarizado con análisis de senderos por Máxima Verosimilitud para infraestructura y logro académico. Se encontró que el incremento de alumnos por grupo y el número de alumnos por clase aumenta la cantidad de alumnos que obtienen niveles de ejecución elemental tanto en habilidad lectora como en habilidad matemática. Así también, disminuye el número de alumnos con desempeño excelente en ambas habilidades. Estos resultados respaldan la evidencia que indica que la infraestructura escolar afecta el desempeño o logro educativo.Under human capital theory, education is seen as sponsor of human and economic capital. Investment in human capital in the medium term may be reflected in the students' academic achievement. Academic achievement is an indicator of the effectiveness of education policies, however, in Latin America there are few studies analyzing effects of inputs or investment spending on student performance. In this study were considered 538 high schools (vocational School) in order to assess effects of number of students per classroom and number of students per class in academic achievement. We carry out a confirmatory factorial analysis and a structural model by Maximum-likelihood Paths for infrastructure and academic achievement. Was found that increase of students per classroom and per class have negative effects because these increase on quantity of students with low levels on reading and mathematical abilities. Also, was reducing the number of students with excellent performance in both skills. These results support the evidence that scholar infrastructure has effects on academic achievement

Relationship between postharvest diseases resistance and mineral composition of citrus fruit

reen and blue moulds, due to the pathogenic action of Penicillium digitatum and Penicillium italicum respectively are the main cause of orange losses during postharvest. Under Mediterranean climate conditions, both together are responsible for 80% of total postharvest citrus fruit decay. The type of orchard production system, field location with different types of climate and soil has a main influence on mineral composition of fruits. The mineral composition of fruits can have a significant impact on fruit quality and shelf life during postharvest period. These include effects on fruit colour, texture, disease susceptibility, juice composition and development of physiological disorders. Oranges from different regions from South of Spain and Portugal and from three different production systems (conventional, integrated and organic) were studied to evaluate whether both factors (origin and production system) affected the degree of fruit sensitivity to decay. Results indicate that the sensitivity to green or blue mould is determined better by the origin of fruit than by the system of production.info:eu-repo/semantics/publishedVersio

Java API for MiAPE Generation

Comunicaciones a congreso

The imperative for quality control programs in Monkeypox virus DNA testing by PCR: CIBERINFEC quality control

Monkeypox; PCR; Quality controlVerola del mico; PCR; Control de qualitatViruela del mono; PCR; Control de calidadTo evaluate molecular assays for Mpox diagnosis available in various clinical microbiology services in Spain through a quality control (QC) approach. A total of 14 centers from across Spain participated in the study. The Reference Laboratory dispatched eight serum samples and eight nucleic acid extracts to each participating center. Some samples were spiked with Mpox or Vaccinia virus to mimic positive samples for Mpox or other orthopox viruses. Participating centers provided information on the results obtained, as well as the laboratory methods used. Among the 14 participating centers seven different commercial assays were employed, with the most commonly used kit being LightMix Modular Orthopox/Monkeypox (Mpox) Virus (Roche®). Of the 12 centers conducting Mpox determinations, concordance ranged from 62.5% (n = 1) to 100% (n = 11) for eluates and from 75.0% (n = 1) to 100% (n = 10) for serum. Among the 10 centers performing Orthopoxvirus determinations, a 100% concordance was observed for eluates, while for serum, concordance ranged from 87.5% (n = 6) to 100% (n = 4). Repeatedly, 6 different centers reported a false negative in serum samples for Orthopoxvirus diagnosis, particularly in a sample with borderline Ct = 39. Conversely, one center, using the TaqMan™ Mpox Virus Microbe Detection Assay (Thermo Fisher), reported false positives in Mpox diagnosis for samples spiked with vaccinia virus due to cross-reactions. We observed a positive correlation of various diagnostic assays for Mpox used by the participating centers with the reference values. Our results highlight the significance of standardization, validation, and ongoing QC in the microbiological diagnosis of infectious diseases, which might be particularly relevant for emerging viruses.This research was supported by CIBER (Strategic Action for Monkeypox)—Consorcio Centro de Investigación Biomédica en Red—(CB 2021), Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación and Unión Europea—NextGenerationEU. A. d. S. is supported by ‘Instituto de Salud Carlos III’ (grant number JR22/00055)