14979 research outputs found
Sort by
Agronomic performance of Raphanus sativus L. cultivars grown under different spacings
Get PDFAn ideal spacing between plants should be established for the optimization of radish (Raphanus sativus L.) crops since the plant spatial distribution of plants affects the crop yield. This study was conducted aiming to evaluate the agronomic performance of radish cultivars grown under different spacings. The experiment was conducted at the Experimental Field of the Federal Institute of Education, Science, and Technology of Maranhão, in Codó, MA, Brazil, from June to July 2017. The experiment was conducted in a randomized block design with five replications, using a 2×2 factorial arrangement. The factors consisted of 2 cultivars (Sparkler Ponta Branca and Saxa) and 2 spacings between plants (5 and 8cm), totaling 20 experimental plots. Data were collected in 6 plants from each experimental plot. The agronomic parameters: total fresh weight (TFW), root fresh weight (RFW), root mean diameter (RMD), root means length (RML), and root yield (RY) of the radish plants were evaluated. The factors (cultivars and spacing between plants) had no significant effect on TFW, RFW, RML, and RMD. The spacing between plants has a significant effect on the yield of radish crops of the cultivar Saxa, and higher yields are found when using the spacing of 5cm
Tree Level FCNC from Models with a Flavored Peccei-Quinn Symmetry
Get PDFA Peccei-Quinn~(PQ) symmetry is proposed, in order to generate a realistic mass matrix ansatz with five texture-zeros for both quark and lepton sector in the Standard Model~(SM). Limiting our analysis to Hermitian mass matrices we show that this requires a minimum of 4 Higgs doublets.
The price we pay is to have Yukawa values in the lepton sector much lower than 1, but consistent with the experimental values. Since the PQ charges are non-universal the model features Flavor-Changing Neutral Currents~(FCNC) at the tree level. We calculate the FCNC couplings of the most general low-energy effective Lagrangian for the axion in a procedure valid for an arbitrary number of Higgs doublets. Finally, we report the allowed region in the parameter space obtained from the measurements of branching ratios of semileptonic meson decays
Factores de atracción y expulsión de médicos migrantes. Estudio de caso de Pedro Aguirre Cerda
Get PDFLas funciones y sus gráficas - Manual
Get PDFLa experiencia en la enseñanza de cursos de cálculo muestra una notoria desigualdad en los estudiantes que ingresan a instituciones de educación superior en cuanto a los conocimientos que sirven de fundamento para una adecuada apropiación de esta importante parte de las matemáticas, que va desde claras deficiencias y desconocimiento, hasta niveles aceptables de comprensión y uso en este campo.
Fundamento esencial para los cursos de cálculo, en particular, lo constituye el conocimiento de las funciones, sus clases, por la relación entre los elementos de los conjuntos, por los conjuntos que la conforman o por su forma analítica. Así mismo, la construcción de sus gráficas, permiten identificar sus peculiaridades, las propiedades que muestran, en forma clara, sus diferencias y similitudes
Perfil nutricional según niveles socio-económicos y menús proporcionados en un comedor social de México
Get PDF
Orígenes y transformaciones del aprendizaje en línea (E-learning). Innovaciones educativas mediadas por paradigmas tecnológicos
Get PDFLa pandemia asociada con el COVID19 ha consolidado el uso del
aprendizaje en línea (E-learning) como la modalidad educativa que
todas las instituciones educativas de Colombia deben adecuar para dar
continuidad a los procesos formativos a través de aulas virtuales, que
aseguran el aislamiento y confinamiento de los estudiantes como población
vulnerable. El objetivo de este artículo es describir los procesos históricos
de consolidación del conectivismo instruccional como alternativa educativa
mediada y subordinada a los cambios en los paradigmas y dispositivos
tecnológicos. Resultado de un proyecto de investigación sobre el E-learning
en Colombia, desde un enfoque cualitativo, se realiza un análisis comparativo
de fuentes sobre la Historia de la educación mediada por la informática,
se presenta un relato cronológico de las transformaciones del aprendizaje
mediado por los dispositivos electrónicos, así como los retos conectivistas
que tiene el E-learning se sistematizan para su reafirmación como
innovación educativa en tiempos de crisis y no solo un medio tecnológico
para dar continuidad a las prácticas y tradiciones de aprendizaje presencial
Biofertilizer potential of digestates from small-scale biogas plants in the Cuban context
Get PDFThe residual sludge from anaerobic digestion known as digestate has been used as a valuable biofertilizer, but the effect of the substrate, the configuration of the reactor and the operating parameter changes the quality and amounts of nutrients in it. Therefore, it is necessary to know its potential characteristic of fertilizer to apply it correctly in crops of national interest. The aim of this work was to characterize the digestate generated from three biodigester technologies (fixed dome, floating drum and tubular) and three substrates: swine manure, cow manure, and co-digestion of swine and cow manure obtained in the province of Sancti Spíritus, Cuba, in terms of nutrient and matter content. For this purpose, stratified statistical sampling was carried out to ensure representative samples and descriptive statistical techniques were used to process the analyses. The digestate was divided into liquid and solid fractions according to the dry matter content (15%). The content of organic matter and ash represented around 50% for both fractions, which enhances its value as a soil conditioner. The nutrient content of both fractions showed good fertilizing properties, having a nutrient ratio (NH4+:PO43-:K+:SO42-:Mg2+:Ca2+) in the liquid (0.002:0.80:0.10:1.00:0.89:0.93) and solid (0.0003:0.96:0.002:1.00:0.52:0.50) fractions, that would contribute to the return nutrients to the soil. The quality of the liquid fraction as irrigation water was assessed as good, according to the relationship between the concentration of the nutrients (Ca, Mg, Na and K) and hardness. Further research is needed on the appropriate dosage for the different crops, and its contribution to sustainable agriculture in the Cuban context
Environmental offering and coffee cup quality (Coffea arabica L.) Var. Castillo in southern Colombia
Get PDFThe determinant factors of coffee cup quality are highly variable and depend on their interaction with coffee production and benefit. This study aimed to analyze soil and climatic factors and their association with the cup quality of Castillo coffee variety of three to five years of age from production units in ecotypes 220A and 221A of the Department of Nariño. The study farms were located in three different altitudinal ranges: ≤1500 m, between 1501 and 1700 m, and >1700 m. Soil, climate, and coffee cup quality variables were analyzed through principal component analysis and cluster analysis. A low level of association was found between climatic and soil nutritional factors and coffee cup quality. Soil Mn, Fe, and Cu contents showed the highest association levels with cup quality, indicated by an average score of 80.89. The highest values of photosynthetically active radiation -PAR- and thermal amplitude were found in La Unión - Nariño, and these variables were associated with the group that obtained the highest cup quality score (82.58). Cup quality was not associated with elevation since the highest scores (85.5 and 82.33) were obtained from production units located at ≤1500 m.a.s.l. and >1700 m.a.s.l, respectively
