Nociones conceptuales de función en los estudiantes de noveno grado

Esta investigación surge de nuestras prácticas como educadores matemáticos sobre las persistentes dificultades de los estudiantes al momento de asociar las representaciones con el objeto función y usar dichas nociones en el tratamiento de situaciones problema. Esta investigación es de corte cualitativa, donde mediante un estudio descriptivo y exploratorio buscamos una interpretación detallada sobre la realidad de los estudiantes frente al estudio del concepto de función. Uno de los hallazgos se refiere a las escasas experiencias de los estudiantes a temprana edad sobre el tratamiento numérico de situaciones problema que puedan orientar a los estudiantes a ideas algebraicas como la generalidad, la expresión de una generalización o la idea de variación y función. Misma realidad infiere que la interpretación gráfica de los estudiantes atañe a una interpretación discreta de los datos. Es decir, que ellos desconocen la variación implícita allí, por lo tanto, no logra visualizar, generalizar ni representar un proceso continuo expreso en una función.In this degree work, we present the results obtained in a teaching experience on the conceptual notions of function expressed by the Ninth grade students belonging to two different educational institutions, public and the other private. This research emerges from our practices as mathematical educators about the persistent difficulties of students when associating representations with the object function and using such notions in the problem situations treatment. This research is qualitative, where through a descriptive and exploratory study we seek for a detailed interpretation about the reality of the students facing the study of the concept of function. One of the findings refers to the scarce experiences of students at an early age about the numerical treatment of problem situations that can guide students to algebraic ideas such as generality, the expression of a generalization or the idea of variation and function. Same reality infers that the graphic interpretation of the students concerns a discrete interpretation of the data. That is to say, they do not know the implicit variation there, therefore, they cannot visualize, generalize or represent a continuous process expressed in a function

Reporte Anual Monitoreo 2018: Territorio Sostenible Adaptado al Clima de Olopa, Guatemala

En el año 2018, el Programa de Investigación de CGIAR en Cambio Climático Agricultura y Seguridad Alimentaria (CCAFS por sus siglas en inglés) del Grupo Consultivo para la Investigación Agrícola Internacional (CGIAR por sus siglas en inglés) en el marco del proyecto “Generando evidencia sobre la Agricultura Sostenible Adaptada al Clima con perspectiva de género para informar políticas en Centroamérica” financiado por el Centro Internacional de Investigaciones para el Desarrollo (IDRC), realizó el monitoreo de prácticas ASAC implementadas en hogares del Territorio Sostenible Adaptado al Clima (TeSAC) de Olopa, departamento de Chiquimula en Guatemala. En total se encuestaron 279 agricultores, pertenecientes a 158 hogares de seis comunidades (Prensa –Centro y Arriba, Nochan, El Guayabo, Tituque, Tuticopote y Valle Nuevo). Los resultados muestran que la mayoría de los hogares (75% de 150 hogares) es encabezado por hombres. La mayor parte de la población indica no haber tenido acceso a la educación, siendo mayor el porcentaje en las mujeres que en los hombres (59% versus 39%). In 2018, the CGIAR Research Program on Climate Change Agriculture and Food Security (CCAFS) in the framework of the project “Generating evidence on gender-sensitive climate-smart agriculture to inform policy in Nicaragua and Guatemala”, financed by the International Development Research Center (IDRC), monitored ASAC practices implemented in homes in the Climate-Smart Village (CSV) of Olopa, department of Chiquimula in Guatemala. In total, 279 farmers were surveyed, belonging to 158 households in six communities (Prensa –Centro and Arriba, Nochan, El Guayabo, Tituque, Tuticopote and Valle Nuevo). The results show that the majority of households (75% of 150 households) are headed by men. The majority of the population indicates that they have not had access to education, the percentage being higher in women than in men (59% versus 39%)

Editorial: Neurodegenerative Diseases: Looking Beyond the Boundaries of the Brain

Neurodegenerative Diseases: Looking Beyond the Boundaries of the Brai

A measure of market orientation: development and validation in a different cultural context

Durante décadas, investigadores y profesionales en marketinghan proclamado que la adopción de una filosofía orientada al consumidor,es la clave para desarrollar y mantener una ventaja competitiva sostenibleen empresas que operan en un entorno de alta competitividad. Sin embargo,el interés no ha sido suficiente para disipar algunas preocupacionessobre el dominio de dicho constructo, así como de la metodología seguidapara su medición en diferentes contextos culturales. Este artículo examinala fiabilidad y validez de tres escalas para medir la orientación al mercadoen un contexto internacional de habla española. Los resultados confirmanlos obtenidos a partir de esfuerzos de investigación anteriores. El estudiode las tres escalas, cuando se combinan, sugiere la existencia de seis dimensionesque pueden ser medidas con dieciocho ítems

Proposal for a fuzzy logic-based system to determine cardiovascular risk

One of the key variables to determine the level of cardiovascular risk is the heart rate variability, which associates different metrics such as average of the RR intervals (average RR), standard deviation of the RR intervals (SDRR) and percentage of differences greater than 50 ms in RR intervals (pRR50). Given that these metrics make use of different measurement units, scales, and ranges, it is necessary to determine an output risk level in intelligible terms, taking as input the values of each one of them. Thus, this article proposes the development of a system based on fuzzy logic to determine the percentage or cardiovascular risk level. The fuzzy system is connected to an Arduino board with a heart rate sensor where the heart rate and heart rate variability values are obtained, so they are used to calculate the risk level metrics. Using the input values of each metric, as well as the 3 membership functions of the inputs, the output membership function, and a total of 18 inference rules defined from the inputs and outputs, the system obtains the output cardiovascular risk level. The fuzzy system was implemented using free hardware and software tools, making it available in medical campaigns for the early identification of heart conditions

Desarrollo de un índice de medición del pensamiento crítico en la formación profesional

RESUMEN: Objetivo. Construir y validar un índice de medición del pensamiento crítico (PC) en la formación profesional. Métodos. Estudio cuantitativo transversal del tipo de validación de pruebas. Luego de revisar la producción científica en PC, la definición del concepto y sus dominios conceptuales, se construyó una escala de 65 ítems de preguntas cerradas sobre análisis de casos que evalúan PC. La escala fue sometida a valoración de expertos para luego ser aplicada a 53 estudiantes de pregrado (35 de enfermería y 18 de sociología) con el fin de evaluar la validez y la confiabilidad. Resultados.La escala de 65 ítems tiene una varianza explicada del 61.3% y está compuesta por cinco dominios de PC: inferencia, evaluación, argumentación, análisis e interpretación. Se obtuvo un coeficiente alfa de Cronbach de 0.61. Conclusión. La escala propuesta para evaluar las habilidades del PC del estudiante converge con conceptos de autores reconocidos con la teoría de PC y es adecuada para ser utilizada como índice de medición de PC en la formación profesional.ABSTRACT: Objective. This research sought to construct and validate a measurement index of critical thinking (CT) in professional formation. Methods. Transversal, quantitative, test validation-type study. After reviewing scientific production in CT, which permitted defining the concept and its conceptual domains, a 65- item scale was constructed of closed questions on the analysis of cases evaluating CT. The scale was subjected to expert evaluation to then be applied to 53 undergraduate students (35 from nursing and 18 from sociology) to evaluate validity and reliability. Results. The 65-item scale has an explained variance of 61.3% and is comprised of five CT domains: inference, evaluation, argumentation, analysis, and interpretation. A Cronbach’s alpha coefficient of 0.61 was obtained. Conclusion. The scale proposed to assess students’ CT skills converges with concepts by known authors with the CT theory and is adequate for use as a CT measurement index in professional formation

Modulatory Role of Sensory Innervation on Hair Follicle Stem Cell Progeny during Wound Healing of the Rat Skin

BACKGROUND: The bulge region of the hair follicle contains resident epithelial stem cells (SCs) that are activated and mobilized during hair growth and after epidermal wounding. However, little is known about the signals that modulate these processes. Clinical and experimental observations show that a reduced supply of sensory innervation is associated with delayed wound healing. Since axon terminals of sensory neurons are among the components of the bulge SC niche, we investigated whether these neurons are involved in the activation and mobilization of the hair stem cells during wound healing. METHODOLOGY/PRINCIPAL FINDINGS: We used neonatal capsaicin treatment to reduce sensory terminals in the rat skin and performed morphometric analyses using design-based stereological methods. Epithelial proliferation was analyzed by quantifying the number of bromodeoxyuridine-labeled (BrdU(+)) nuclei in the epidermis and hair follicles. After wounding, the epidermis of capsaicin-treated rats presented fewer BrdU(+) nuclei than in control rats. To assess SC progeny migration, we employed a double labeling protocol with iododeoxyuridine and chlorodeoxyuridine (IdU(+)/CldU(+)). The proportion of double-labeled cells was similar in the hair follicles of both groups at 32 h postwounding. IdU(+)/CldU(+) cell proportion increased in the epidermis of control rats and decreased in treated rats at 61 h postwounding. The epidermal volume immunostained for keratin 6 was greater in treated rats at 61 h. Confocal microscopy analysis revealed that substance P (SP) and calcitonin gene-related peptide (CGRP) receptor immunoreactivity were both present in CD34(+) and BrdU-retaining cells of the hair follicles. CONCLUSIONS/SIGNIFICANCE: Our results suggest that capsaicin denervation impairs SC progeny egress from the hair follicles, a circumstance associated with a greater epidermal activation. Altogether, these phenomena would explain the longer times for healing in denervated skin. Thus, sensory innervation may play a functional role in the modulation of hair SC physiology during wound healing

Supernumerary Formation of Olfactory Glomeruli Induced by Chronic Odorant Exposure: A Constructivist Expression of Neural Plasticity

It is accepted that sensory experience instructs the remodelling of neuronal circuits during postnatal development, after their specification has occurred. The story is less clear with regard to the role of experience during the initial formation of neuronal circuits, whether prenatal or postnatal, since this process is now supposed to be primarily influenced by genetic determinants and spontaneous neuronal firing. Here we evaluated this last issue by examining the effect that postnatal chronic exposure to cognate odorants has on the formation of I7 and M72 glomeruli, iterated olfactory circuits that are formed before and after birth, respectively. We took advantage of double knock-in mice whose I7 and M72 primary afferents express green fluorescent protein and β-galactosidase, correspondingly. Our results revealed that postnatal odorant chronic exposure led to the formation of permanent supernumerary I7 and M72 glomeruli in a dose and time dependent manner. Glomeruli in exposed mice were formed within the same regions of olfactory bulb and occupy small space volumes compared to the corresponding single circuits in non-exposed mice. We suggest that local reorganization of the primary afferents could participate in the process of formation of supernumerary glomeruli. Overall, our results support that sensory experience indeed instructs the permanent formation of specific glomeruli in the mouse olfactory bulb by means of constructivist processes