Perfiles de orientaciones de metas y autoconcepto de estudiantes de Educación Secundaria

The objective of this study is to identify possible combinations of multiple goals that lead to different goal orientation profiles and to determine whether there are significant group differences in self-concept dimensions. The Achievement Goals Tendencies Questionnaire (AGTQ) and the Self-Description Questionnaire-II (SDQ-II) were administered to a sample of 2,022 students of Compulsory Secondary education, ranging in age from 12 to 16 years (M = 13.81, SD = 1.35). Cluster analysis identified four profiles of motivational goals: a group of students with a generalized high motivation profile, a group of students with generalized low motivation profile, a group of students with a predominance of learning goals and achievement goals, and a last group of students with a predominance of achievement goals and social reinforcement goals. Results reveal statistically significant differences among the profiles obtained regarding self-concept dimensions.El objetivo de este estudio es identificar si existen combinaciones de múltiples metas que dan lugar a diferentes perfiles de orientaciones de metas motivacionales, así como comprobar si existen diferencias significativas entre los grupos obtenidos respecto a las dimensiones del autoconcepto. El Achievement Goal Tendencies Questionnaire (AGTQ) y el Self-Description Questionnaire-II (SDQ-II) fueron administrados a una muestra de 2.022 estudiantes de Educación Secundaria Obligatoria de 12 a 16 años (M = 13.81; DT = 1.35). El análisis de conglomerados ha identificado cuatro perfiles de metas motivacionales: un grupo de alumnos/as con un perfil de múltiples metas altas, un grupo de estudiantes con un perfil de múltiples metas bajas, un grupo de alumnos/as con un predominio de metas de aprendizaje y metas de logro y un último grupo de estudiantes con predominio de metas logro y metas de refuerzo social. Los resultados revelan diferencias estadísticamente significativas entre los perfiles obtenidos con respecto a las dimensiones del autoconcepto.This work was carried out through the Research Project SEJ 2004-07311/EDUC of the Plan Nacional de Investigación Científica, Desarrollo e Innovación Tecnológica del M.E.C. [National Plan of Scientific Research, Development and Technological Innovation of the Ministry of Education and Culture] awarded to the first author

Sociometric types, behavioral categories and intellectual abilities in adolescents

El objetivo de este estudio fue analizar la relación entre tipos sociométricos, categorías conductuales y aptitudes intelectuales en una muestra de 1349 (51.7% varones) adolescentes españoles de 12 a 16 años. La identificación sociométrica de los estudiantes se realizó mediante el Programa Socio y para el análisis de las aptitudes intelectuales se administró el Test de Aptitudes Mentales Primarias (PMA; Thurstone, 1938; TEA, 1996). Las hipótesis del estudio plantean, en primer lugar, que los estudiantes nominados positivamente por sus iguales presentarán puntuaciones significativamente superiores en las diferentes escalas del PMA que los estudiantes nominados negativamente por sus compañeros y, en segundo lugar, que las aptitudes intelectuales serán una variable predictora estadísticamente significativa de los tipos sociométricos y categorías conductuales. Los resultados muestran que los estudiantes nominados positivamente obtuvieron puntuaciones significativamente más altas en las diferentes aptitudes intelectuales que los nominados negativamente. Las aptitudes intelectuales resultaron un predictor significativo de los tipos sociométricos, ya que a medida que aumenta la puntuación en las diferentes aptitudes intelectuales los estudiantes presentaron mayor probabilidad de ser nominados positivamente por sus compañeros.The aim of this study was to analyze the relationship between sociometric types, behavioral categories, and intellectual abilities in a sample of 1349 (51.7% boys) Spanish adolescents, ranging in age from 12 to 16 years. The students' sociometric nomination was performed by the Programa Socio and academic self-concept was measured by the Primary Mental Abilities Test (PMA; Thurstone, 1938; TEA, 1996). The hypotheses of the study suggest, firstly, that students positively nominated by their peers will present significantly higher scores on different scales of the PMA than students negatively nominated by their peers and, secondly, that intellectual skills will be a predictor variable statistically significant of sociometric types and behavioral categories. Results show that students nominated positively obtained significantly higher scores on the different intellectual abilities that nominees negatively. Intellectual abilities were a significant predictor of sociometric types because with increasing the score on the different intellectual abilities students were more likely to be nominated by their peers positively.Este trabajo ha sido realizado a través del Proyecto SEJ 2004-07311/EDUC perteneciente al Plan Nacional de Investigación Científica, Desarrollo e Innovación Tecnológica del MEC concedido al primer autor

Myocardial injury determination improves risk stratification and predicts mortality in COVID-19 patients

Background: Despite being associated with worse prognosis in patients with COVID-19, systematic determination of myocardial injury is not recommended. The aim of the study was to study the effect of myocardial injury assessment on risk stratification of COVID-19 patients.Methods: Seven hundred seven consecutive adult patients admitted to a large tertiary hospital with confirmed COVID-19 were included. Demographic data, comorbidities, laboratory results and clinical outcomes were recorded. Charlson comorbidity index (CCI) was calculated in order to quantify the degree of comorbidities. Independent association of cardiac troponin I (cTnI) increase with outcomes was evaluated by multivariate regression analyses and area under curve. In addition, propensity-score matching was performed to assemble a cohort of patients with similar baseline characteristics.Results: In the matched cohort (mean age 66.76 ± 15.7 years, 37.3% females), cTnI increase above the upper limit was present in 20.9% of the population and was associated with worse clinical outcomes, including all-cause mortality within 30 days (45.1% vs. 23.2%; p = 0.005). The addition of cTnI to a multivariate prediction model showed a significant improvement in the area under the time-dependent receiver operating characteristic curve (0.775 vs. 0.756, DC-statistic = 0.019; 95% confidence interval 0.001–0.037). Use of renin–angiotensin–aldosterone system inhibitors was not associated with mortality after adjusting by baseline risk factors.Conclusions: Myocardial injury is independently associated with adverse outcomes irrespective of baseline comorbidities and its addition to multivariate regression models significantly improves their performance in predicting mortality. The determination of myocardial injury biomarkers on hospital admission and its combination with CCI can classify patients in three risk groups (high, intermediate and low) with a clearly distinct 30-day mortality

Drive of a brushless direct current motor with hall type sensors

In the present article, an electronic bi-directional power converter applied to the control of a brushless direct current motor (Brushless) was designed, implemented and automatically activated, by means of which part of the electric bicycle is recovered. The kinetic energy is converted to electrical energy efficiently, with a positive ecological impact. The converters were implemented with isolated gate transistors (IGBT), these devices have high switching frequency, which allows significantly reduce the harmonics, which is very attractive in different applications therefore the results of this work can be generalized for the speed control of higher power direct current motors which can not be fed directly from the electrical system and require a variable speed, as is the case of electric vehicles.En el presente artículo se diseño, implemento y se caracterizo un convertidor electrónico de potencia bidireccional aplicado al control de un motor de corriente directa sin escobillas (Brushless), para el impulso de una bicicleta eléctrica de modo automático, mediante el cual se recupera parte de la energía cinética y se convierte a energía eléctrica de modo eficiente, con un impacto ecológico positivo. Los convertidores se implementaron con transistores de compuerta aislada (IGBT), estos dispositivos tienen alta frecuencia de conmutación, lo que permite reduce significativamente los armónicos, lo cual es muy atractivo en diferentes aplicaciones por lo tanto los resultados del presente trabajo se pueden generalizar para el control de velocidad de motores de corriente directa de mayor potencia los cuales no puedan ser alimentados directamente del sistema eléctrico y requieran de una velocidad variable, como es el caso de los vehículos eléctricos

Social Anxiety Scale for Adolescents and School Anxiety Inventory: Psychometric properties in French adolescents

School and social anxiety are common problems and have a significant impact on youths’ development. Nevertheless, the questionnaires to assess these anxious symptoms in French adolescents have limitations. The aim of this study is to provide a French version of the Social Anxiety Scale for Adolescents (SAS-A) and the School Anxiety Inventory (SAI), analysing their psychometric properties by the factor structure, internal consistency, and convergent validity. The SAS-A and the SAI were collectively administered in a sample of 1011 French adolescents (48.5% boys) ranging in age from 11 to 18 years. Confirmatory factor analyses replicated the previously identified correlated three-factor structure of the SAS-A and the correlated four-factor structure of the SAI. Acceptable internal consistency indexes were found for SAS-A and SAI scores. Correlations supported the convergent validity of the questionnaires’ subscales. Overall, results supported the internal consistency and validity of the French versions of the SAS-A and SAI

A ferrous oxalate mediated photo-Fenton system: Toward an increased biodegradability of indigo dyed wastewaters

This study assessed the applicability of a ferrous oxalate mediated photo-Fenton pretreatment for indigo-dyed wastewaters as to produce a biodegradable enough effluent, likely of being derived to conventional biological processes. The photochemical treatment was performed with ferrous oxalate and hydrogen peroxide in a Compound Parabolic Concentrator (CPC) under batch operation conditions. The reaction was studied at natural pH conditions (5–6) with indigo concentrations in the range of 6.67–33.33 mg L−1, using a fixed oxalate-to-iron mass ratio (C2O42−/Fe2+ = 35) and assessing the system's biodegradability at low (257 mg L−1) and high (1280 mg L−1) H2O2 concentrations. In order to seek the optimal conditions for the treatment of indigo dyed wastewaters, an experimental design consisting in a statistical surface response approach was carried out. This analysis revealed that the best removal efficiencies for Total Organic Carbon (TOC) were obtained for low peroxide doses. In general it was observed that after 20 kJ L−1, almost every treated effluent increased its biodegradability from a BOD5/COD value of 0.4. This increase in the biodegradability was confirmed by the presence of short chain carboxylic acids as intermediate products and by the mineralization of organic nitrogen into nitrate. Finally, an overall decrease in the LC50 for Artemia salina indicated a successful detoxification of the effluent

Variation in stem mortality rates determines patterns of above-ground biomass in Amazonian forests: implications for dynamic global vegetation models

Understanding the processes that determine above-ground biomass (AGB) in Amazonian forests is important for predicting the sensitivity of these ecosystems to environmental change and for designing and evaluating dynamic global vegetation models (DGVMs). AGB is determined by inputs from woody productivity [woody net primary productivity (NPP)] and the rate at which carbon is lost through tree mortality. Here, we test whether two direct metrics of tree mortality (the absolute rate of woody biomass loss and the rate of stem mortality) and/or woody NPP, control variation in AGB among 167 plots in intact forest across Amazonia. We then compare these relationships and the observed variation in AGB and woody NPP with the predictions of four DGVMs. The observations show that stem mortality rates, rather than absolute rates of woody biomass loss, are the most important predictor of AGB, which is consistent with the importance of stand size structure for determining spatial variation in AGB. The relationship between stem mortality rates and AGB varies among different regions of Amazonia, indicating that variation in wood density and height/diameter relationships also influences AGB. In contrast to previous findings, we find that woody NPP is not correlated with stem mortality rates and is weakly positively correlated with AGB. Across the four models, basin-wide average AGB is similar to the mean of the observations. However, the models consistently overestimate woody NPP and poorly represent the spatial patterns of both AGB and woody NPP estimated using plot data. In marked contrast to the observations, DGVMs typically show strong positive relationships between woody NPP and AGB. Resolving these differences will require incorporating forest size structure, mechanistic models of stem mortality and variation in functional composition in DGVMs