Determinants of researchgate (rg) score for the top 100 of Latin American universities at webometrics

This paper has the purpose of establishing the variables that explain the behavior of ResearchGate for the Top100 Latin American universities positioned in Webometrics database for January 2017. For this purpose, a search was carried out to get information about postgraduate courses and professors at the institutional websites and social networks, obtaining documents registered in Google Scholar. For the data analysis, the econometric technique of ordinary least squares was applied, a cross-sectional study for the year 2017 was conducted, and the individuals studied were the first 100 Latin American universities, obtaining a coefficient of determination of 73.82%. The results show that the most significant variables are the number of programs, the number of teacher’s profiles registered in Google Scholar, the number of subscribers to the institutional YouTube channel, and the GDP per capita of the university origin country. Variables such as (i) number of undergraduate programs, (ii) number of scientific journals; (iii) number of documents found under the university domain; (iv) H-index of the 1st profile of researcher at the university; (vi) number of members of the institution; (v) SIR Scimago ranking of Higher Education Institutions; (vi) number of tweets published in the institutional account; (vii) number of followers in the Twitter institutional account; (vii) number of “likes” given to the institutional count, were not significantCorporación Universitaria Minuto de Dios, Fundación Universitaria Konrad Lorenz, Universidad Nacional Experimental Politécnica, Universidad Centroccidental “Lisandro Alvarado, Universidad de la Costa

Evaluation of resistive-plate-chamber-based TOF-PET applied to in-beam particle therapy monitoring

Particle therapy is a highly conformal radiotherapy technique which reduces the dose deposited to the surrounding normal tissues. In order to fully exploit its advantages, treatment monitoring is necessary to minimize uncertainties related to the dose delivery. Up to now, the only clinically feasible technique for the monitoring of therapeutic irradiation with particle beams is Positron Emission Tomography (PET). In this work we have compared a Resistive Plate Chamber (RPC)-based PET scanner with a scintillation-crystal-based PET scanner for this application. In general, the main advantages of the RPC-PET system are its excellent timing resolution, low cost, and the possibility of building large area systems. We simulated a partial-ring scannerbeam monitoring, which has an intrinsically low positron yield compared to diagnostic PET. In addition, for in-beam PET there is a further data loss due to the partial ring configuration. In order to improve the performance of the RPC-based scanner, an improved version of the RPC detector (modifying the thickness of the gas and glass layers), providing a larger sensitivity, has been simulated and compared with an axially extended version of the crystal-based device. The improved version of the RPC shows better performance than the prototype, but the extended version of the crystal-based PET outperforms all other options. based on an RPC prototype under construction within the Fondazione per Adroterapia Oncologica (TERA). For comparison with the crystal-based PET scanner we have chosen the geometry of a commercially available PET scanner, the Philips Gemini TF. The coincidence time resolution used in the simulations takes into account the current achievable values as well as expected improvements of both technologies. Several scenarios (including patient data) have been simulated to evaluate the performance of different scanners. Initial results have shown that the low sensitivity of the RPC hampers its application to hadro

Influence of sociological aspects on the level of physical activity in physical education students

Adopting and maintaining an active lifestyle for adolescent students, seems to be impaired and influenced by several factors, among them stand out environmental, psychological and social factors. Thus, the general objectives of this study were submitted to study and understand the extent to which these environmental, social and personal factors help and influence the level of physical activity (PA) by the adolescents in school age. More specifically, we will study: (1) the possible association between level of physical activity, age and gender; (2) consider and determine whether there is an association between socioeconomic variables and physical activity level of the population sample; (3) assess on the possible association between environmental variables and perceived physical activity of the adolescents. The sample consisted of 286 high school students, male gender (n = 125) and female (n = 161) aged between 15 and 18 years of age. As an instrument of study, a questionnaire was used. The main results of this study demonstrate a possible relationship between gender and level of PA, while boys tend to be more active than girls and also an association between socioeconomic variables and level of physical activity

U-Control Chart Based Differential Evolution Clustering for Determining the Number of Cluster in k-Means

The automatic clustering differential evolution (ACDE) is one of the clustering methods that are able to determine the cluster number automatically. However, ACDE still makes use of the manual strategy to determine k activation threshold thereby affecting its performance. In this study, the ACDE problem will be ameliorated using the u-control chart (UCC) then the cluster number generated from ACDE will be fed to k-means. The performance of the proposed method was tested using six public datasets from the UCI repository about academic efficiency (AE) and evaluated with Davies Bouldin Index (DBI) and Cosine Similarity (CS) measure. The results show that the proposed method yields excellent performance compared to prior researches

Correlação entre o conteúdo inorgânico e a polimerização da matriz orgânica das resinas compostas para restaurações dentárias: uma revisão narrativa

Introduction: In recent years, resin-matrix composite materials have revealed a fast technological improvement for dental applications. However, there are still some drawbacks related to the chemical composition, polymerization, and mechanical properties of resin-matrix composites with consequences in long-term clinical success. Objective: This study aimed to perform a narrative review regarding the effects of inorganic fillers on the organic matrix polymerization of resin-matrix composites. Materials and Methods: A search was performed in PubMed using relevant related key terms related to the chemical composition, properties and polymerization of resin matrix composites. Relevant studies published between 2001 and 2021 were selected. Results: The studies included in the present research provided relevant information on the chemical composition and properties of resin composites and polymerization factors, including the time, wavelength mode, and equipment. Studies have reported that silica and silicate nano-scale particles improve light transmission through resin-matrix composites and the degree of conversion of monomers in the organic matrix. Micrometric particles with a high refractive index can decrease the degree of conversion of monomers in the organic matrix. Conclusion: The polymerization of resin-matrix composites is affected by light scattering due to the type of inorganic particles and the differences in refractive indexes of inorganic and organic contents.Introdução: Nos últimos anos, as resinas compostas têm sido melhoradas em termos tecnológicos, permitindo o alcance de melhores prognósticos na medicina dentária. Entretanto, subsistem algumas limitações relacionadas com a composição química e as propriedades das resinas compostas com consequências no sucesso clínico a longo prazo. Objetivo: O objetivo deste trabalho foi realizar uma revisão narrativa sobre a influência da componente inorgânica na polimerização da matriz orgânica das resinas compostas usadas para restauração dentária. Materiais e Métodos: A pesquisa foi realizada na plataforma PubMed utilizando termos de pesquisa relacionados com a composição química, propriedades e a polimerização das resinas compostas, para seleção de artigos relevantes ao tema. Resultados: Os estudos identificados reportam diferentes fatores relacionados com a polimerização incluindo modo, tempo, equipamento e a composição química das resinas compostas. Os estudos indicam que partículas nanométricas à base de sílica ou silicatos promovem uma maior transmissão de luz à matriz orgânica o que favorece a polimerização do material. Por outro lado, partículas micrométricas com um alto índice de refração podem diminuir o grau de conversão dos monómeros da matriz orgânica. Conclusão: A polimerização das resinas compostas é afetada pela dispersão da luz, devido ao tamanho das partículas inorgânicas e aos índices de refração da componente orgânica e inorgânica. De fato, um maior controlo da composição química e do tamanho de partículas inorgânicas aumenta o grau de polimerização das resinas compostas

Conocimiento ecológico, alimentación tradicional y clasificación frío-caliente: la perspectiva de los niños tseltales de Tenejapa, Chiapas

The objective of this paper is to analyze the knowledge of Tseltal children regarding agricultural production systems, the products derived from such systems, and their cold or hot classification. Through a workshop, interviews with informants, and field research, we analyze children’s knowledge concerning the production systems, plants and animals associated with them, and their cold or hot characteristics. Our results show that children’s participation in food production systems and other subsistence activities is the best way of transmitting traditional ecological knowledge. Tseltal children have extensive knowledge of their environment, production systems, and food traditions. Preservation of traditional food systems can sustain the environment and ensure food security and food self-sufficiency.El principal objetivo de este trabajo es analizar el conocimiento ecológico de niños tseltales en relación con los sistemas de producción agrícola, los productos que los componen y su clasificación fría o caliente. A través de un taller, entrevistas a informantes clave e investigación de campo se estudió el conocimiento de los niños con respecto a los diversos sistemas productivos, plantas y animales silvestres asociados a ellos y sus características frías o calientes. Los resultados muestran que la participación activa de los infantes en los sistemas productivos y de obtención de alimentos es la mejor manera de transmisión del conocimiento ecológico tradicional. Los niños tseltales poseen un amplio conocimiento sobre su medioambiente, los sistemas productivos y su tradición alimentaria. La conservación del CET y de los sistemas alimentarios tradicionales puede preservar el medioambiente y garantizar la seguridad y autosuficiencia alimentaria

Modeling Kepler transit light curves as false positives: Rejection of blend scenarios for Kepler-9, and validation of Kepler-9d, a super-Earth-size planet in a multiple system

Light curves from the Kepler Mission contain valuable information on the nature of the phenomena producing the transit-like signals. To assist in exploring the possibility that they are due to an astrophysical false positive, we describe a procedure (BLENDER) to model the photometry in terms of a "blend" rather than a planet orbiting a star. A blend may consist of a background or foreground eclipsing binary (or star-planet pair) whose eclipses are attenuated by the light of the candidate and possibly other stars within the photometric aperture. We apply BLENDER to the case of Kepler-9, a target harboring two previously confirmed Saturn-size planets (Kepler-9b and Kepler-9c) showing transit timing variations, and an additional shallower signal with a 1.59-day period suggesting the presence of a super-Earth-size planet. Using BLENDER together with constraints from other follow-up observations we are able to rule out all blends for the two deeper signals, and provide independent validation of their planetary nature. For the shallower signal we rule out a large fraction of the false positives that might mimic the transits. The false alarm rate for remaining blends depends in part (and inversely) on the unknown frequency of small-size planets. Based on several realistic estimates of this frequency we conclude with very high confidence that this small signal is due to a super-Earth-size planet (Kepler-9d) in a multiple system, rather than a false positive. The radius is determined to be 1.64 (+0.19/-0.14) R(Earth), and current spectroscopic observations are as yet insufficient to establish its mass.Comment: 20 pages in emulateapj format, including 8 tables and 16 figures. To appear in ApJ, 1 January 2010. Accepted versio

Structural basis for redox regulation of cytoplasmic and chloroplastic triosephosphate isomerases from Arabidopsis thaliana

"In plants triosephosphate isomerase (TPI) interconyerts glyceraldehyde 3-phosphate (G3P) and dihydroxyacetone phosphate (DHAP) during glycolysis, gluconeogenesis, and the Calvin-Benson cycle. The nuclear genome of land plants encodes two tpi genes, one gene product is located in the cytoplasm and the other is imported into the chloroplast. Herein we report the crystal structures of the TPIs from the vascular plant Arabidopsis thaliana (AtTPIs) and address their enzymatic modulation by redox agents. Cytoplasmic TPI (cTPI) and chloroplast TPI (pdTPI) share more than 60% amino acid identity and assemble as (beta-alpha)(8) dimers with high structural homology. cTPI and pdTPI harbor two and one accessible thiol groups per monomer respectively. cTPI and pdTPI present a cysteine at an equivalent structural position (C13 and C15 respectively) and cTPI also contains a specific solvent accessible cysteine at residue 218 (cTPI-C218). Site directed mutagenesis of residues pdTPI-C15, cTPI-C13, and cTPI-C218 to serine substantially decreases enzymatic activity, indicating that the structural integrity of these cysteines is necessary for catalysis. AtTPIs exhibit differential responses to oxidative agents, cTPI is susceptible to oxidative agents such as diamide and H2O2, whereas pdTPI is resistant to inhibition. Incubation of AtTPIs with the sulfhydryl conjugating reagents methylmethane thiosulfonate (MMTS) and glutathione inhibits enzymatic activity. However, the concentration necessary to inhibit pdTPI is at least two orders of magnitude higher than the concentration needed to inhibit cTPI. Western-blot analysis indicates that residues cTPI-C13, cTPI-C218, and pdTPI-C15 conjugate with glutathione. In summary, our data indicate that AtTPIs could be redox regulated by the derivatization of specific AtTPI cysteines (cTPI-C13 and pdTPI-C15 and cTPI-C218). Since AtTPIs have evolved by gene duplication, the higher resistance of pdTPI to redox agents may be an adaptive consequence to the redox environment in the chloroplast.

Determination of contents based on learning styles through artificial intelligence

The study presents the development of a platform for structuring adaptive courses based on active, reflexive, theoretical and pragmatic learning styles using artificial intelligence techniques. To this end, the following phases were followed: search, analysis and classification of information about the process of generating content for courses; analysis and coding of the software component for generating content according to learning styles; and application of tests for validation and acceptance. The main contribution of the paper is the development of a model using neural networks and its integration in an application server to determine the contents that correspond to the active, reflexive, theoretical and pragmatic learning styles