Representaciones matemáticas de estudiantes pre-universitarios en la resolución de un problema de optimización

Se presentan resultados de un estudio sobre representación matemática de estudiantes pre-universitarios en un proceso de resolución de un problema de optimización. Se analizaron sus respuestas escritas mediante análisis de discurso con base en teorías de la representación y de resolución de problemas. Se encontró que la mayoría sigue una estrategia fundamentalmente de tipo algorítmico, con un limitado número de representaciones matemáticas, entre las que predomina la medición, sin una noción sólida de variable y de relaciones funcionales, sin esquemas de monitoreo del procedimiento y de la solución obtenida, y con limitaciones en el conocimiento base. Se comentan brevemente alternativas educativas a esta situación

Gestión educativa y uso de la plataforma aprendo en casa en la institución educativa 2024, distrito de Los Olivos, 2021

El presente trabajo de investigación tiene como objetivo determinar qué relación existe entre la gestión educativa y el uso de la plataforma Aprendo en casa en la Institución Educativa 2024, distrito de Los Olivos, 2021; el diseño metodológico es del tipo descriptivo correlacional; respetando el método hipotético deductivo, con una población censal de ochenta estudiantes del primer año bajo la técnica de la encuesta y por medio de dos cuestionarios para cada una de las variables; los cuales fueron validados por tres expertos y la confiabilidad mediante la aplicación del Alfa; presentando como resultados que existe una correlación de alta (Rho = 0.813 y sig.=0.00) lo cual mostró como conclusión que la utilización de las TIC permite mejorar la gestión educativa; Por otro lado, los docentes durante la cuarentena han ido hacia el autoaprendizaje de las tecnologías de información. Se recomienda el Fortalecimiento del uso de las competencias digitales por medio de capacitaciones a los docentes sobre el uso de la plataforma Aprendo en casa de enfoque holística; con la finalidad de lograr la idoneidad del manejo del aula remota, logrando la efectividad de la calidad en el proceso de enseñanza – aprendizaje

Gestión educativa y uso de la plataforma aprendo en casa en la institución educativa 2024, distrito de Los Olivos, 2021

El presente trabajo de investigación tiene como objetivo determinar qué relación existe entre la gestión educativa y el uso de la plataforma Aprendo en casa en la Institución Educativa 2024, distrito de Los Olivos, 2021; el diseño metodológico es del tipo descriptivo correlacional; respetando el método hipotético deductivo, con una población censal de ochenta estudiantes del primer año bajo la técnica de la encuesta y por medio de dos cuestionarios para cada una de las variables; los cuales fueron validados por tres expertos y la confiabilidad mediante la aplicación del Alfa; presentando como resultados que existe una correlación de alta (Rho = 0.813 y sig.=0.00) lo cual mostró como conclusión que la utilización de las TIC permite mejorar la gestión educativa; Por otro lado, los docentes durante la cuarentena han ido hacia el autoaprendizaje de las tecnologías de información. Se recomienda el Fortalecimiento del uso de las competencias digitales por medio de capacitaciones a los docentes sobre el uso de la plataforma Aprendo en casa de enfoque holística; con la finalidad de lograr la idoneidad del manejo del aula remota, logrando la efectividad de la calidad en el proceso de enseñanza – aprendizaje.Lima NorteEscuela de PosgradoGestión de Políticas PúblicasEducación y calidad educativaApoyo a la reducción de brechas y carencias en la educación en todos sus nivelesEducación de calida

Publication venue recommendation using profiles based on clustering

This work was supported by the Spanish “Agencia Estatal de Investigación” [grant number PID2019-106758GB-C31/AEI/10.13039/501100011033]; the Span- ish “Programa operativo FEDER Andalucı́a 2014-2020 de la Junta de Andalucı́a y la Universidad de Granada” [grant number A-TIC-146-UGR20]; and the Eu- ropean Regional Development Fund (ERDF-FEDER).In this paper we study the venue recommendation problem in order to help researchers to identify a journal or conference to submit a given paper. A com- mon approach to tackle this problem is to build profiles defining the scope of each venue. Then, these profiles are compared against the target paper. In our approach we will study how clustering techniques can be used to construct topic-based profiles and use an Information Retrieval based approach to obtain the final recommendations. Additionally, we will explore how the use of author- ship, representing a complementary piece of information, helps to improve the recommendations

Committee-Based Profiles for Politician Finding

One step towards breaking down barriers between citizens and politicians is to help people identify those politicians who share their concerns. This paper is set in the field of expert finding and is based on the automatic construction of politicians’ profiles from their speeches on parliamentary committees. These committee-based profiles are treated as documents and are indexed by an information retrieval system. Given a query representing a citizen’s concern, a profile ranking is then obtained. In the final step, the different results for each candidate are combined in order to obtain the final politician ranking. We explore the use of classic combination strategies for this purpose and present a new approach that improves state-of-the-art performance and which is more stable under different conditions. We also introduce a two-stage model where the identification of a broader concept (such as the committee) is used to improve the final politician ranking.This work has been funded by the Spanish Ministerio de Economı́a y Competitividad under projects TIN2013-42741-P and TIN2016-77902-C3-2-P, and the European Regional Development Fund (ERDF-FEDER)

Marginal seal stability of one bottle adhesives in Class V vs. Class I cavities

The aim of this study was to test the influence of two different cavity configurations on marginal stability of recent one bottle "etch & rinse” and "self-etch” adhesives in Class V vs. Class I cavities, before and after thermo-mechanical loading under simulation of dentinal fluid. Forty human upper molars were selected and assigned to five experimental groups. Intrapulpal pressure was maintained during cavity preparation, restoration placement, finishing and stressing. Standardized Class I and V-Shaped Class V cavities were prepared on each tooth. Half of the margins of Class V cavities were located in enamel and half in dentin. All cavities were restored with different adhesives systems and a nano-hybrid composite. Materials were light-cured using a LED unit. Restored teeth were loaded in a computer-controlled chewing machine with 1.2 million mechanical occlusal cycles simultaneously with 3,000 thermal cycles (5-50-5°C). Impressions were made with polyvinylsiloxane of each restoration before and after loading. Gold-coated epoxy replicas were prepared for SEM examination at ×200 magnification. Significant differences between materials were found both before and after loading (Kruskal-Wallis, Bonferroni, p < 0.05). Significant differences were also found between Class I and V restorations (Wilcoxon Matched-Pairs Signed-Rank Test, p < 0.05). Even before thermo-mechanical loading, none of the groups had 100% continuous margin. Marginal seal stability of recent one bottle "etch & rinse” and "self-etch” adhesives are significantly different and susceptible to cavity configuratio

Magneto-mechanical surfaces design

Magneto-mechanically active surfaces (MMAS) represent a new family of nano/micro-structured surfaces in which motion is induced by an external magnetic field. Under the name of artificial cilia, biomimetic cilia, magnetic actuated patterns, nanopillars, etc., published works in this area continue their quick growth in number. Notwithstanding their potential application in microfluidic, chemical sensors, catalytic processes and microelectronics to increase device perfomances, there is still a lot to do in the development of these materials. Improvement and optimization of the performance of these structures are essential tasks in order to fulfil their complete development. Along this article, a critical review involving the main aspects in the design of the patterned nanocomposites will be presented.Authors wish to thank Spanish Ministerio de Economía y Competitividad for finantial support under grant MAT2014-57557-R

Evaluation of the cell viability of human Wharton's jelly stem cells for use in cell therapy

Human umbilical cord Wharton's jelly stem cells (HWJSCs) are gaining attention as a possible clinical source of mesenchymal stem cells for cell therapy and tissue engineering due to their high accessibility, expansion potential, and plasticity. We employed a combination of highly sensitive techniques to determine the average cell viability levels and proliferation capabilities of 10 consecutive cell passages of cultured HWJSCs and then used RNA microarrays to identify genes associated with changes in cell viability levels. We found an initial decrease in cell viability from the first to the third cell passage followed by an increase until the sixth passage and a final decrease from the sixth to tenth cell passages. The highest cell viability levels corresponded to the fifth and sixth passages. The intracellular ionic contents of potassium, sodium, and chlorine suggest that the lower cell viability levels at passages 2, 3, and 8-10 may be associated with apoptotic cell death. In fact, gene expression analysis revealed that the average cell viability was significantly associated with genes with a function in apoptotic cell death, especially pro-apoptotic FASTKD2, BNIP3L genes and anti-apoptotic TNFAIP8 and BCL2L2 genes. This correlation with both pro-apoptotic and anti-apoptotic genes suggests that there may be a complex live-death equilibrium in cultured HWJSCs kept in culture for multiple cell passages. In this study, the highest cell viability levels corresponded to the fifth and sixth HWJSC passages, suggesting that these passages should be preferentially employed in cell therapy or tissue engineering protocols using this cell type

Predicting IR Personalization Performance using Pre-retrieval Query Predictors

Personalization generally improves the performance of queries but in a few cases it may also harms it. If we are able to predict and therefore to disable personalization for those situations, the overall performance will be higher and users will be more satisfied with personalized systems. We use some state-of-the-art pre-retrieval query performance predictors and propose some others including the user profile information for the previous purpose. We study the correlations among these predictors and the difference between the personalized and the original queries. We also use classification and regression techniques to improve the results and finally reach a bit more than one third of the maximum ideal performance. We think this is a good starting point within this research line, which certainly needs more effort and improvements.This work has been supported by the Spanish Andalusian “Consejerı́a de Innovación, Ciencia y Empresa” postdoctoral phase of project P09-TIC-4526, the Spanish “Ministerio de Economı́a y Competitividad” projects TIN2013-42741-P and TIN2016-77902-C3-2-P, and the European Regional Development Fund (ERDF-FEDER)

Microstructure Evolution in a Fast and Ultrafast Sintered Non-Equiatomic Al/Cu HEA

One of the attractive characteristics of high entropy alloys (HEAs) is the ability to tailor their composition to obtain specific microstructures and properties by adjusting the stoichiometry to obtain a body-centered cubic (BCC) or face-centered cubic (FCC) structure. Thus, in this work, the target composition of an alloy of the FeCrCoNi family has been modified by adjusting the Al/Cu ratio in order to obtain a BCC crystalline structure. However, processing conditions always play a key role in the final microstructure and, therefore, in this work, the microstructure evolution of FeCrCoNiAl1.8Cu0.5 HEA sintered by different powder metallurgy (PM) techniques has been investigated. The techniques used range from the conventional PM sintering route, that uses high heating rates and sintering times, going through a fast sintering technique such as spark plasma sintering (SPS) to the novel and promising ultrafast sintering technique electrical resistance sintering (ERS). Results show that the increase in the processing time favours the separation of phases and the segregation of elements, which is reflected in a substantial change in the hardness of the alloy. In conclusion, the ERS technique is presented as a very promising consolidation technique for HEA.The authors gratefully acknowledge the financial support of MAT4.0-CM project funded by Madrid region under programme S2018/NMT-4381. J. Cornide also acknowledges funding from the Spanish Ministry of Science and Innovation (IJCI-2017-31348)