RESUMO
Temperature is the main factor that impacts germination and therefore the success of annual crops, such as chia (Salvia hispanica L.), whose seeds are known for their high nutritional value related to its oil. The effect of temperature on germination is related to cardinal-temperature concepts that describe the range of temperature over which seeds of a particular species can germinate. Therefore, in this study, in addition to calculated germinative parameters such as total germination and germination rate of S. hispanica seeds, the effectiveness of non-linear models for estimating the cardinal temperatures of chia seeds was also determined. We observed that germination of S. hispanica occurred in cold to moderate-high temperatures (10-35 °C), having an optimal range between 25 and 35 °C, with the highest GR and t50 at 30 °C. Temperatures higher than 35 °C significantly reduced germination. Output parameters of the different non-linear models showed that the response of chia germination to temperature was best explained by beta models (B). Cardinal temperatures calculated by the B1 model for chia germination were: 2.52 ± 6.82 °C for the base, 30.45 ± 0.32 °C for the optimum, and 48.58 ± 2.93 °C for the ceiling temperature.
RESUMO
Resumen Objetivo: Identificar las estrategias de afrontamiento que usan los adolescentes mexicanos ante situaciones que provocan miedo. Método: El tipo de estudio fue no experimental. Los partici pantes fueron 400 adolescentes mexicanos de nivel secundaria (50 % hombres y 50 % mujeres), Media de edad = 13.90 (DE= 0.96). Un instrumento midió la intensidad del miedo ante nueve tipos de situaciones: violencia social, animales, estar solo, médicos, situaciones sociales, lo desco nocido, violencia doméstica, escuela y muerte (a = .93). Por medio de preguntas abiertas se pre guntó a los participantes qué harían ante cada una de las situaciones, lo que permitió identificar el tipo de afrontamiento. Resultados: Las mujeres informaron mayor miedo que los hombres en todas las situaciones, excepto en miedo a la escuela, donde ellas tuvieron mayor puntaje. El patrón general fue que las mujeres usan más estrategias de desahogo emocional y búsqueda de apoyo, mientras que los hombres usan estrategias directas al problema, agresivas y de distracción. En particular, ante el miedo a la muerte, los hombres usan estrategias evitativas, distracción y búsqueda de apoyo, mientras que las mujeres usan estrategias directas al problema, desahogo emocional, búsqueda de apoyo, evitativas, distracción y agresivas. Ante el miedo a lo desconocido, los varones usan estrategias de distracción, agresivas y directas al problema, mientras que las muje res usan desahogo emocional, directo al problema y agresivas. Las estrategias de afrontamiento no son buenas ni malas, su conveniencia depende del apoyo que brindan para resolver la situación que genera miedo.
Abstract Objective: This study aims to identify coping strategies used by Mexican teenagers in situations that elicit fear. Method: This study was non-experimental. The sample consisted of 400 Mexican teenager in secondary level (50 % men and 50 % women) mean age = 13.90 (of= 0.96). Research ers used an instrument to measure the intensity of the fear assumed in nine different types of situations such as: social violence, animals, living alone, doctors, social situations, the unknown, domestic violence, school and death (a =. 93). Through an open-ended question, the participants were asked the following: what would they do in those situations? Allowing them to identify the way they cope with these situations. Results: Women reported greater fear than men in all situ ations except fear of school, where they scored higher. Women generally used more strategies of emotional relief and searching for support while men used aggressive and distraction strategies in relation to those situations. In relation to the fear of death, men assume avoidance strategies, distraction and search for support while women assume direct strategies such as: emotional relief, search for support, avoidance distraction and aggression. In conclusion, coping strategists are not good or bad; it depends on the support given to solve the situation that generates fear.
RESUMO
Soil bulk density (b) data are needed for a wide range of environmental studies. However, b is rarely reported in soil surveys. An alternative to obtain b for data-scarce regions, such as the Rio Doce basin in southeastern Brazil, is indirect estimation from less costly covariates using pedotransfer functions (PTF). This study primarily aims to develop region-specific PTFs for b using multiple linear regressions (MLR) and random forests (RF). Secondly, it assessed the accuracy of PTFs for data grouped into soil horizons and soil classes. For that purpose, we compared the performance of PTFs compiled from the literature with those developed here. Two groups of data were evaluated as covariates: 1) readily available soil properties and 2) maps derived from a digital elevation model and MODIS satellite imagery, jointly with lithological and pedological maps. The MLR model was applied step-wise to select significant predictors and its accuracy assessed by means of cross-validation. The PTFs developed using all data estimated b from soil properties by MLR and RF, with R2 of 0.41 and 0.51, respectively. Alternatively, using environmental covariates, RF predicted b with R2 of 0.41. Grouping criteria did not lead to a significant increase in the estimates of b. The accuracy of the regional PTFs developed for this study was greater than that found with the compiled PTFs. The best PTF will be firstly used to assess soil carbon stocks and changes in the Rio Doce basin.
Assuntos
Análise do Solo , Características do Solo , Previsões , Florestas , Modelos Estatísticos , SoloRESUMO
Soil bulk density (b) data are needed for a wide range of environmental studies. However, b is rarely reported in soil surveys. An alternative to obtain b for data-scarce regions, such as the Rio Doce basin in southeastern Brazil, is indirect estimation from less costly covariates using pedotransfer functions (PTF). This study primarily aims to develop region-specific PTFs for b using multiple linear regressions (MLR) and random forests (RF). Secondly, it assessed the accuracy of PTFs for data grouped into soil horizons and soil classes. For that purpose, we compared the performance of PTFs compiled from the literature with those developed here. Two groups of data were evaluated as covariates: 1) readily available soil properties and 2) maps derived from a digital elevation model and MODIS satellite imagery, jointly with lithological and pedological maps. The MLR model was applied step-wise to select significant predictors and its accuracy assessed by means of cross-validation. The PTFs developed using all data estimated b from soil properties by MLR and RF, with R2 of 0.41 and 0.51, respectively. Alternatively, using environmental covariates, RF predicted b with R2 of 0.41. Grouping criteria did not lead to a significant increase in the estimates of b. The accuracy of the regional PTFs developed for this study was greater than that found with the compiled PTFs. The best PTF will be firstly used to assess soil carbon stocks and changes in the Rio Doce basin.(AU)