La mirada profesional sobre la argumentación científica escolar en la formación inicial

La investigación tiene como objetivo caracterizar la mirada profesional de la argumentación en ciencias, en futuros docentes de la licenciatura en Biología y Química de la Universidad de Caldas-Colombia, utilizando el video clip como estrategia de reflexión de sus prácticas de aula. La conclusión fundamental ratifica, en primer lugar, el carácter gradual de apropiación de la competencia y, en segundo lugar, que los futuros docentes disminuyen el nivel de desempeño de las destrezas que componen la competencia a medida que se aumenta el nivel de complejidad de la misma, situación que exige mayor desarrollo y continuidad en los procesos de formación de docentes para lograr mejores comprensiones de cómo promover la argumentación en ciencias

Caracterización y evolución de los modelos de enseñanza de la argumentación en clase de ciencias en la educación primaria

Tesi presentada el 29 de octubre de 2012 a la Universitat Autònoma de Barcelona. Departament de Didàctica de la Matemàtica i de les Ciències Experimental

Sexual harassment among peers and adolescent dating violence

El presente estudio ha analizado la presencia de violencia sexual entre compañeros y en las parejas adolescentes y jóvenes. Específicamente se han estudiado las diferencias por sexo, edad y estadio de la relación sentimental tanto en violencia sexual entre iguales como en las parejas, en una muestra de 490 adolescentes (55,7% chicos, 44,3% chicas, edad media 16.08 años). Los resultados descriptivos mostraron la misma incidencia de violencia sexual entre iguales y en las parejas. Respecto al sexo, los chicos presentaron mayor implicación como agresores de sus iguales y de sus parejas, pero no se encontraron diferencias con relación a los índices de victimización. Se encontró un efecto importante del estadio de la relación: la violencia sexual entre iguales fue más frecuente entre los que se encontraban en “relaciones casuales” y “grupos mixtos” mientras que la violencia sexual entre parejas fue más frecuente entre los que se encontraban en “relaciones serias”. Para la edad, solo se encontraron diferencias en la violencia sexual entre parejas, siendo que los chicos y chicas más mayores resultaron más implicados que los más pequeños.This paper presents a study about peer and dating sexual harassment among adolescents. Specifically, differences by sex, age and the developmental stage of the romantic relationships were analyzed in both, peer and dating sexual harassment in a sample of 490 adolescents (55,7% boys and 44,3% girls, mean age 16.08). Descriptive data showed that the presence of peer and dating sexual harassment was similar. Boys were more perpetrators in both, peer and dating contexts but no differences by sex were found for victimization indexes. An important effect of the developmental-stage of the relationships was found: peer sexual harassment were more frequent in “casual” and “mixed gender” stage whereas dating sexual harassment was more frequent in “serious relationship”. For age, just differences in dating sexual harassment were found: older adolescents were more involved than younger ones

A comparison between maximum likelihood and Bayesian estimation of stochastic frontier production models

In this paper, the finite sample properties of the maximum likelihood and Bayesian estimators of the half-normal stochastic frontier production function are analyzed and compared through a Monte Carlo study. The results show that the Bayesian estimator should be used in preference to the maximum likelihood owing to the fact that the mean square error performance is substantially better in the Bayesian framewor

Effects of exercise in addition to a family-based lifestyle intervention program on hepatic fat in children with overweight

ClinicalTrials.gov ID: NCT02258126Background: Paediatric hepatic steatosis is highly prevalent and closely related to type 2 diabetes. Aims: To determine whether the addition of supervised exercise to a family-based lifestyle- and psycho-educational intervention results in greater reduction of percentage hepatic fat (HF), adiposity, and cardiometabolic risk factors in children with overweight/obesity. Methods: The study subjects of this non-randomized, two-arm, parallel design, clinical trial were 116 overweight/obese children (10.6±1.1 years, 53.4% girls) living in Vitoria-Gasteiz (Spain). For 22 weeks they followed either a lifestyle- and psycho-education program (control intervention [CI], N=57), consisting of two family-based education sessions/month, or the same plus supervised exercise (intensive intervention [II], N=59) focused mainly on high-intensity aerobic workouts (3 sessions/week, 90 min/session). The primary outcome was the change in percentage HF (as measured by MRI) between baseline and the end of the intervention period. Secondary outcomes included changes in body mass index (BMI), fat mass index (FMI), abdominal fat (measured by dual-X-ray-absorptiometry), blood pressure, triglycerides, high density lipoprotein, low density lipoprotein, gamma-glutammyl-transferase, glucose and insulin concentrations. Results: A total of 102 children completed the trial (N=53 and N=49 in the CI and II groups, respectively). Percentage HF decreased only in the II group (-1.20±0.31% vs. 0.04±0.30%, II and CI, respectively), regardless of baseline value and any change in adiposity (P<0.01). BMI, FMI, abdominal fat (P≤0.001) and insulin (P<0.05) were reduced in both groups. Conclusions: Multicomponent intervention programs that include exercise training may help reduce, adiposity, insulin resistance and hepatic steatosis in overweight/obese children.Spanish Ministry of Health "Fondos de Investigation Sanitaria del Institute de Salud Carlos III" PI13/01335Spanish Ministry of Industry and Competitiveness DEP2016-78377-REU Fondos Estructurales de la Union Europea (FEDER) funds ("Una manera de hacer Europa")Spanish Ministry of Education, Culture and Sports FPU14/03329Education Department of the Government of the Basque Country PRE_2016_1_0057 PRE_2017_2_0224 PRE_2018_2_0057University of Granada Plan Propio de Investigacion 2016-Excellence actions: Unit of Excellence on Exercise and Health (UCEES)Junta de Andalucia, Consejeria de Conocimiento, Investigacion y Universidades (FEDER) SOMM17/6107/UG

Sobre la capacidad de separar los dos errores en el modelo de frontera estocástica normal/half-normal

In this paper, a simulation experiment is carried out in the framework of the normal/half -normal stochastic frontier model in order to analyse its ability to disentangle the two types of errors that form the composite error. According to the results obtained through the mean bias and the mean squared error of the parameters and efficiencies, and via Spearman rank correlation between actual and estimated efficiencies, a good performance of the model is only obtained when considering medium -sized or large samples and the variance of the inefficiencies highly contributes to that of the composite error. The problems of wrong skewness and absence of random error are also addressed. The influence on the results of selecting a wrong distribution for the inefficienc y term is also analysedEn este artículo, se lleva a cabo un experimento de simulación en el contexto del modelo con frontera estocástica normal/half -normal para analizar su capacidad de separar los dos tipos de error que forman el error compuesto. Según los resultados obtenidos a través del sesgo medio y el error cuadrático medio de los parámetros y las eficiencias, y mediante el coeficiente de correlación por rangos de Spearman entre las eficiencias reales y las estimadas, se obtiene un buen comportamiento del modelo solo cuando se consideran muestras de tamaño me diano o grande y la varianza de las ineficiencias contribuye de forma muy importante a la del error compuesto. Los problemas de la asimetría errónea y de la ausencia de errores aleatorios también son abordados. La influencia en los resultados de selecciona r una distribución errónea para el término de ineficiencia también se analiz

Bayesian estimation of the half-normal regression model with deterministic frontier

A regression model with deterministic frontier is considered. This type of model has hardly been studied, partly owing to the difficulty in the application of maximum likelihood estimation since this is a non-regular model. As an alternative, the Bayesian methodology is proposed and analysed. Through the Gibbs algorithm, the inference of the parameters of the model and of the individual efficiencies are relatively straightforward. The results of the simulations indicate that the utilized method performs reasonably wel

Estimating non-stationary common factors : Implications for risk sharing

In this paper, we analyze and compare the finite sample properties of alternative factor extraction procedures in the context of non-stationary Dynamic Factor Models (DFMs). On top of considering procedures already available in the literature, we extend the hybrid method based on the combination of principal components and Kalman filter and smoothing algorithms to non-stationary models. We show that, unless the idiosyncratic noise is non-stationary, procedures based on extracting the factors using the nonstationary original series work better than those based on differenced variables. The results are illustrated in an empirical application fitting non-stationary DFM to aggregate GDP and consumption of the set of 21 OECD industrialized countries. The goal is to check international risk sharing is a short or long-run issue.Financial support is acknowledged from Projects ECO2015-70331-C2-1-R and ECO2015-70331-C2-2-R(MINECO/FEDER) by the Spanish Government

Effects of a Family-Based Lifestyle Intervention Plus Supervised Exercise Training on Abdominal Fat Depots in Children With Overweight or Obesity. A Secondary Analysis of a Nonrandomized Clinical Trial

IMPORTANCE Excess abdominal fat is a major determinant in the development of insulin resistance and other metabolic disorders. Increased visceral adipose tissue (VAT) seems to precede the development of insulin resistance and is therefore a prime target of childhood lifestyle interventions aimed at preventing diabetes. OBJECTIVES To examine the effect of added exercise to a family-based lifestyle intervention program designed to reduce VAT plus subcutaneous (ASAT), intermuscular (IMAAT), and pancreatic (PAT) adipose tissue in children with overweight or obesity and to explore the effect of changes in VAT on insulin resistance. DESIGN, SETTING, AND PARTICIPANTS This 2-group, parallel-design clinical trial was conducted in Vitoria-Gasteiz, Spain. A total of 116 children with overweight or obesity participated and were assigned to a 22-week family-based lifestyle program (control group [n = 57]) or the same program plus an exercise intervention (exercise group [n = 59]). Data were collected between September 1, 2014, and June 30, 2017, and imaging processing for fat depot assessments and data analysis were performed between May 1, 2019, and February 12, 2021. INTERVENTIONS The compared interventions consisted of a family-based lifestyle and psychoeducation program (two 90-minute sessions per month) and the same program plus supervised exercise (three 90-minute sessions per week). MAIN OUTCOMES AND MEASURES The primary outcome of this study was the change in VAT between baseline and 22 weeks as estimated by magnetic resonance imaging. The secondary outcomes were changes in ASAT, IMAAT, and PAT. The effect of changes in VAT area on insulin resistance was also recorded. RESULTS The 116 participants included in the analysis (62 girls [53.4%]) had a mean (SD) age of 10.6 (1.1) years, and 67 (57.8%) presented with obesity. Significantly greater reductionswere recorded for the exercise group in terms of reduction in VAT (−18.1%vs −8.5%for the control group; P = .004), ASAT (−9.9%vs −3.0%; P = .001), and IMAAT (−6.0%vs −2.6%; P = .02) fat fractions compared with the control group. Changes in VAT explained 87.6%of the improvement seen in insulin resistance (β = −0.102 [95%CI, −0.230 to −0.002]). CONCLUSIONS AND RELEVANCE These findings suggest that the addition of exercise to a lifestyle intervention program substantially enhanced the positive effects on abdominal fat depots in children with overweight or obesity. In addition, the reduction in VAT seemed to largely mediate the improvement of insulin sensitivity. These results highlight the importance of including exercise as part of lifestyle therapies aimed at treating childhood obesity and preventing the development of type 2 diabetes.Spanish Ministry of Health's Fondos de Investigacion Sanitaria del Instituto de Salud Carlos III PI13/01335 Spanish Government DEP2016-78377European Commission 0011-1365-2019-000085Regional Government of Navarra's Department of Economic Development - ERDF Government of Navarra's Department of Health 47/2021Ministry of Science and Innovation, Spain (MICINN) Spanish Government FJC2018-037925-IMarie Sklodowska Curie 101028929 European CommissionEducation Department of the Government of the Basque Country BES-2017-080770 PRE_2016_1_0057 PRE_2017_2_0224 PRE_2018_2_0057 PRE_2019_2_0004Junta de Andalucia, Consejeria de Conocimiento, Investigacion y Universidades, ERDF SOMM17/6107/UG