Growth and formation of inverse GaP and InP opals

Opals consist of an ordered array of SiO2 spheres. This leads to a modulation of the refractive index and hence photonic stop bands behaviour over the visible/IR range of the electro-magnetic spectrum. The exact position of the stop bands depends on the size of the silica spheres. However, the refractive index contrast between the SiO2 spheres and air spaces is not great enough to open up a full photonic band gap (PBG), only the pseudogap. To increase the contrast the air spaces are filled with a material of high refractive index such as InP or GaP. To further increase the contrast the SiO2 is removed leaving a III-V framework as the inverse opal structure. By use of MOCVD we have been able to infill opals with InP and GaP to such a level that has supported the inversion of the composite forming a structure of air holes within a III-V lattice. XRD and Raman confirmed the quality of the III-V infill, while the extent of the infill was studied by SEM and reflectance measurements

La secuencia didáctica en el aula

La experiencia desarrollada con los estudiantes de Didáctica II y PracticaPedagógica en la Licenciatura de Ciencias Naturales de la UniversidadSurcolombiana de Neiva-Huila alrededor de una secuencia didáctica para intervenir el aula, muestra las posibilidades que tiene el maestro para desarrollaresa trama entre el saber disciplinar y el pedagógico - didáctico propios deldocente. La secuencia didáctica una interacción entre variables como elcontexto, las dificultades en la enseñanza y aprendizaje de las ciencias naturales,las ideas previas de los estudiantes y sus intereses, los contenidos conceptuales,procedimentales y actitudinales y un diario de campo que permita su reflexión.

Autonomous strategies for the production of argumentative texts in the Peruvian jungle

The objective of this research was to analyze the autonomous strategies for the production of argumentative texts used by elementary school students from an educational institution in the Peruvian jungle, according to the subcategories metacognitive strategies and self-regulation strategies. The methodology is of qualitative approach, with the hermeneutic work method. The informants were 14 students. The technique was the interview where an unstructured interview guide was applied. The results show that most of the students used autonomous strategies for the production of argumentative texts, being the most prevalent those of organization and planning, information search via the Internet, underlining and summarizing. Conclusions: the autonomous strategies for the production of argumentative texts used by primary school students of an educational institution in the Peruvian jungle are in the categories of meta-cognition and self-regulation

La gestión de tesorería en el sector público: alcances y retos para lograr la eficiencia en Latinoamérica

The purpose of the research was to describe and analyze the context of public treasury management in Latin America, which focused on recognizing the scope, the reality in which it is developed and the challenges that must be met for optimal operation. Various approaches have been considered that have made it possible to accurately identify the key factors for its optimal development, the existing problems and the agents with whom they interact, considering elements such as internal control, capital movement records and the performance of officials. This information was obtained through the method of systematic review of indexed scientific and academic literature from reliable portals such as Redalyc, Scielo, Academic Google and Ebsco, likewise, information delimitation criteria were presented, where the journals had to be in the interval of time between the years 2015 and 2021, obtaining 15 articles, which were analyzed in order to develop the discussion and conclusions useful for the area of ​​study and improvement in performance.La investigación tuvo como finalidad describir y analizar el contexto de la gestión de tesorería pública en Latinoamérica, la cual se enfocó en reconocer los alcances, la realidad en la que se desarrolla y los retos que deben cumplirse para un funcionamiento óptimo. Se han considerado diversos enfoques que han permitido identificar con precisión los factores clave para su adecuado desenvolvimiento, las problemáticas existentes y los agentes con los que interactúan, considerándose elementos como el control interno, los registros de movimientos de capital y el desempeño de los funcionarios. Esta información fue obtenida a través del método de revisión sistemática de literatura científica y académica indexada proveniente de portales confiables como Redalyc, Scielo, Google académico y Ebsco, asimismo, se presentaron criterios de delimitación de información, donde las revistas tuvieron que  encontrarse en el intervalo de tiempo comprendido entre los años 2015 y 2021, obteniéndose 15 artículos, que fueron analizados con la finalidad de desarrollar la discusión y las conclusiones de utilidad para el área de estudio y mejora en el desempeño

Criterio y enfoque pedagógico en redes de aprendizaje

El presente documento se origina de las reflexiones hechas en el PUI ITE y en DAEA, y espera ser un punto de partida teórico y de conceptualización para el desarrollo de cursos en línea en la Facultad de Artes, en los cuales estoy colaborando en el semestre en curso. El presente documento espera definir algunos criterios fundamentales a tener en cuenta con el fin de enfrentar un reto de ésta magnitud, con el objetivo de llevar a estos cursos al éxito esperado desde una visión de enseñanza aprendizaje.Para el diseño y desarrollo del curso es imprescindible tener en cuenta la cultura, modelo mental e imaginarios de los usuarios. La red de aprendizaje debe estar vinculada con programas internacionales en línea, cursos, catálogos, bibliotecas, bases de datos y además tener programas conjuntos a nivel internacional, adecuados con los diferentes programas curriculares de la facultad.Los cursos deben pensarse dentro del plan de estudios de las carreras y también como cursos al exterior de la universidad (acreditados para otras universidades), elevando así el potencial para la enseñanza aprendizaje.The present document originates from the reflections done in the PUI ITE and in DAEA, and waiting to be a theoretical starting point and of conceptualization for the development of courses in line in the Faculty of Arts, in which I am collaborating in the current semester. The present document hopes to define some fundamental criteria to bearing in mind in order to magnitude to face a challenge of this one, with the target to take to these courses to the success waited from a vision of education learning.For the design and development of the course it is essential to bear in mind the culture, mental model and imaginary of the users. The network of learning must be linked by international programs in line, courses, catalogues, libraries, databases and also have joint programs on a global scale, adapted by the different programs curriculares of the faculty.The courses must be thought inside the curriculum of the careers and also as courses on the outside of the university (credited for other universities), raising this way the potential for the education learning

Compact High-Velocity Clouds at High Resolution

Six examples of the compact, isolated high-velocity clouds catalogued by Braun & Burton (1999) and identified with a dynamically cold ensemble of primitive objects falling towards the barycenter of the Local Group have been imaged with the Westerbork Synthesis Radio Telescope; an additional ten have been imaged with the Arecibo telescope. The imaging reveals a characteristic core/halo morphology: one or several cores of cool, relatively high-column-density material, are embedded in an extended halo of warmer, lower-density material. Several of the cores show kinematic gradients consistent with rotation; these CHVCs are evidently rotationally supported and dark-matter dominated. The imaging data allows several independent estimates of the distances to these objects, which lie in the range 0.3 to 1.0 Mpc. The CHVC properties resemble what might be expected from very dark dwarf irregular galaxies.Comment: 12 pages, 7 figures, to appear in "The Chemical Evolution of the Milky Way: Stars versus Clusters", eds. F. Matteuchi and F. Giovannelli, Kluwer Academic Publisher

Matrix metalloproteinase 13 modulates intestinal epithelial barrier integrity in inflammatory diseases by activating TNF

Several pathological processes, such as sepsis and inflammatory bowel disease (IBD), are associated with impairment of intestinal epithelial barrier. Here, we investigated the role of matrix metalloproteinase MMP13 in these diseases. We observed that MMP13(-/-) mice display a strong protection in LPS- and caecal ligation and puncture-induced sepsis. We could attribute this protection to reduced LPS-induced goblet cell depletion, endoplasmic reticulum stress, permeability and tight junction destabilization in the gut of MMP13(-/-) mice compared to MMP13(+/+) mice. Both in vitro and in vivo, we found that MMP13 is able to cleave pro-TNF into bioactive TNF. By LC-MS/MS, we identified three MMP13 cleavage sites, which proves that MMP13 is an alternative TNF sheddase next to the TNF converting enzyme TACE. Similarly, we found that the same mechanism was responsible for the observed protection of the MMP13(-/-) mice in a mouse model of DSS-induced colitis. We identified MMP13 as an important mediator in sepsis and IBD via the shedding of TNF. Hence, we propose MMP13 as a novel drug target for diseases in which damage to the gut is essential

World-wide distributions of lactase persistence alleles and the complex effects of recombination and selection

The genetic trait of lactase persistence (LP) is associated with at least five independent functional single nucleotide variants in a regulatory region about 14 kb upstream of the lactase gene [-13910*T (rs4988235), -13907*G (rs41525747), -13915*G (rs41380347), -14009*G (rs869051967) and -14010*C (rs145946881)]. These alleles have been inferred to have spread recently and present-day frequencies have been attributed to positive selection for the ability of adult humans to digest lactose without risk of symptoms of lactose intolerance. One of the inferential approaches used to estimate the level of past selection has been to determine the extent of haplotype homozygosity (EHH) of the sequence surrounding the SNP of interest. We report here new data on the frequencies of the known LP alleles in the 'Old World' and their haplotype lineages. We examine and confirm EHH of each of the LP alleles in relation to their distinct lineages, but also show marked EHH for one of the older haplotypes that does not carry any of the five LP alleles. The region of EHH of this (B) haplotype exactly coincides with a region of suppressed recombination that is detectable in families as well as in population data, and the results show how such suppression may have exaggerated haplotype-based measures of past selection

Vortex deformation and breaking in superconductors: A microscopic description

Vortex breaking has been traditionally studied for nonuniform critical current densities, although it may also appear due to nonuniform pinning force distributions. In this article we study the case of a high-pinning/low-pinning/high-pinning layered structure. We have developed an elastic model for describing the deformation of a vortex in these systems in the presence of a uniform transport current density $J$ for any arbitrary orientation of the transport current and the magnetic field. If $J$ is above a certain critical value, $J_c$, the vortex breaks and a finite effective resistance appears. Our model can be applied to some experimental configurations where vortex breaking naturally exists. This is the case for YBa$_2$Cu$_3$O$_{7-x}$ (YBCO) low angle grain boundaries and films on vicinal substrates, where the breaking is experienced by Abrikosov-Josephson vortices (AJV) and Josephson string vortices (SV), respectively. With our model, we have experimentally extracted some intrinsic parameters of the AJV and SV, such as the line tension $\epsilon_l$ and compared it to existing predictions based on the vortex structure.Comment: 11 figures in 13 files; minor changes after printing proof

El comportamiento organizacional en la gestión educativa pública: retos y perspectivas en el ámbito latinoamericano

The purpose of this article was to describe and analyze the environment of organizational behavior in public educational management in Latin America, through which it was possible to recognize the challenges that must be overcome for efficient management and the perspectives according to the context in which they are developed. Several approaches were considered, gathered from the analysis of the selected articles, which allowed recognizing key elements for the research, such as the implication of human capital management, leadership, communication, etc. The indexed scientific and academic literature was obtained through the systematic review method of articles obtained from reliable portals such as Redalyc, Scielo, Researchgate and Ebsco. The selected articles initially went through exclusion criteria, for this research it was considered that they belong to the time interval corresponding to the years 2015 to 2021, so that as a final result 15 articles were obtained, which were analyzed through analysis tables where the most relevant and useful information for the research was positioned, also, this allowed the development of the discussion and conclusions.El presente artículo tuvo como objetivo describir y analizar el entorno del comportamiento organizacional en la gestión educativa pública en el ámbito latinoamericano, mediante el cual se logró reconocer cuáles son los retos que deben superarse para una gestión eficiente y las perspectivas de acuerdo con el contexto donde se desarrollan. Se han considerado diversos enfoques recogidos del análisis correspondiente a los artículos seleccionados, que han permitido reconocer elementos clave para la investigación, como la implicancia de la gestión de capital humano, el liderazgo, la comunicación, etc. La literatura científica y académica indexada fue obtenida mediante el método de revisión sistemática de artículos obtenidos de portales confiables como Redalyc, Scielo, Researchgate y Ebsco. Los artículos seleccionados inicialmente pasaron por criterios de exclusión, para esta investigación se consideró que pertenezcan al intervalo de tiempo correspondiente entre los años 2015 y 2021, de tal manera que como resultado final se revisaron 15 artículos, los cuales fueron analizados a través de tablas de análisis donde se posicionó la información más relevante y útil para la investigación, asimismo, esta permitió el desarrollo de la discusión y conclusiones