Personalidad Grit y rendimiento anaeróbico en taekwondistas estadounidenses

El propósito de este estudio fue evaluar la relación entre el rendimiento anaeróbico y la personalidad Grit en taekwondistas estadounidenses, su grado de influencia, así como las diferencias que puedan existir entre sexos. Este estudio tuvo una metodología cuantitativa, descriptiva-correlacional, realizada en una población de (n=121) taekwondistas, vinculados a la USAT. La personalidad Grit fue medida mediante la escala Grit, y el rendimiento anaeróbico a través de la prueba del sprint anaeróbico basado en la carrera (Rast). De acuerdo con los resultados se pudo identificar en hombres, una correlación positiva y significativa entre la capacidad y potencia anaeróbica con el Grit (p<0.005 y p<0.007 respectivamente). Asimismo, estas dos variables se relacionaron significativamente con el Grit (p<0.001) en el total de la muestra. En el caso de las mujeres, no hubo relaciones significativas. El índice de fatiga no presentó correlaciones significativas. La personalidad Grit influyó hasta un 14% en la capacidad y potencia anaeróbica en hombres (p<0.001 y p<0.002, respectivamente) y un 12% en estos dos mismos aspectos para la muestra total (p<0.000 en ambos casos). Finalmente, los hallazgos indican una relación entre la potencia, capacidad anaeróbica con la personalidad Grit en hombres y en el total de la muestra, con una influencia significativa del Grit en el rendimiento anaeróbico. No se encontraron tales relaciones en mujeres. Aunque no se hallaron diferencias significativas por sexo en el Grit, capacidad y potencia anaeróbica, sí que se encontró en el índice de fatiga, indicando una disparidad en la resistencia a la fatiga entre sexos.

The purpose of this study was to assess the relationship between anaerobic performance and Grit personality in American taekwondo practitioners, its degree of influence, as well as any differences that may exist between genders. This study employed a quantitative, descriptive-correlational methodology, conducted on a population of (n=121) taekwondo practitioners affiliated with the USAT. Grit personality was measured using the Grit Scale, and anaerobic performance was assessed through the Anaerobic Sprint Test based on running (Rast). According to the results, a positive and significant correlation between anaerobic capacity and power with Grit was identified in men (p<0.005 and p<0.007 respectively). Likewise, these two variables were significantly related to Grit (p<0.001) in the total sample. In the case of women, there were no significant relationships. The fatigue index showed no significant correlations. Grit personality influenced up to 14% in anaerobic capacity and power in men (p<0.001 and p<0.002, respectively) and 12% in these two aspects for the total sample (p<0.000 in both cases). Finally, the findings indicate a relationship between power, anaerobic capacity, and Grit personality in men and the total sample, with a significant influence of Grit on anaerobic performance. Such relationships were not found in women. Although no significant gender differences were found in Grit, anaerobic capacity, and power, differences were found in the fatigue index, indicating a disparity in fatigue resistance between genders.

O objetivo deste estudo foi avaliar a relação entre o desempenho anaeróbico e a personalidade Grit em praticantes de taekwondo americanos, seu grau de influência, bem como as diferenças que possam existir entre os sexos. Este estudo utilizou uma metodologia quantitativa, descritiva-correlacional, realizada em uma população de (n=121) praticantes de taekwondo afiliados à USAT. A personalidade Grit foi medida usando a Escala Grit, e o desempenho anaeróbico foi avaliado através do Teste de Sprint Anaeróbico baseado em corrida (Rast). De acordo com os resultados, foi possível identificar nos homens uma correlação positiva e significativa entre a capacidade e potência anaeróbica com o Grit (p<0.005 e p<0.007, respectivamente). Da mesma forma, essas duas variáveis estavam significativamente relacionadas ao Grit (p<0.001) na amostra total. No caso das mulheres, não foram encontradas relações significativas. O índice de fadiga não apresentou correlações significativas. A personalidade Grit influenciou até 14% na capacidade e potência anaeróbica em homens (p<0.001 e p<0.002, respectivamente) e 12% nesses dois aspectos para a amostra total (p<0.000 em ambos os casos). Finalmente, os achados indicam uma relação entre potência, capacidade anaeróbica e a personalidade Grit em homens e na amostra total, com uma influência significativa do Grit no desempenho anaeróbico. Tais relações não foram encontradas em mulheres. Embora não tenham sido encontradas diferenças significativas por sexo no Grit, capacidade e potência anaeróbica, foi encontrada diferença no índice de fadiga, indicando uma disparidade na resistência à fadiga entre os sexos.

The influence of grit on life satisfaction of Brazilian undergraduate students: academic adaptation as a mediator.

Introduction: In recent years, research in educational contexts has pointed to the role of grit as a variable related to various positive outcomes, including life satisfaction. Academic adaptation seems vital for the success of academic life in college students. Considering university as an important life context for people pursuing higher education, what is the mediating effect of academic adaptation? This study proposed a mediation model to examine the mediating effect of academic adaptation in the relationship grit and life satisfaction. Methods: A sample of 413 undergraduate Brazilian students, age ranging from 18 to 71 years (M = 27.30; SD = 10.20). A correlation analysis was performed between the variables and the following mediation model was tested: Grit (independent variable), academic adaptation (mediating variables) and life satisfaction (dependent variables). Results: Mediation analysis indicated that academic adaptation mediated around 46.80% for the factor of consistency of interests and 40.90% of the relationship with perseverance of effort. Thus, the greater the grit of the university student, the greater the grit, which leads to better satisfaction with life. Discussion: In recent years, research in educational contexts has pointed to the role of grit as a variable related to various positive outcomes. The findings elucidated that grit in academic context could benefit students' adaptation process, and the university's responsibility to improve its students' softskills, not only for the future stage after university, but also during the student's schooling.

Evidencias complementarias de validez de la Escala Grit-S y adaptación de la Escala para medir la agencia y el empoderamiento en Colombia

Introducción: el constructo grit predice el desempeño en distintos dominios; aunque con resultados variables en la estructura de las pruebas. El objetivo de la investigación es aportar evidencias de validez de la Grit-S, a través de la confirmación de la estructura y la convergencia con la Escala para Medir Agencia Personal y Empoderamiento. Método: en primer lugar, estudiantes universitarios (n = 313) de modalidad virtual respondieron la prueba Grit-S y se efectuó un análisis factorial confirmatorio de la prueba. A continuación, se evaluó la convergencia con la Escala para Medir Agencia Personal y Empoderamiento. Resultados: Los hallazgos sugieren mantener la estructura bifactorial de Grit-S. Por otra parte, se adaptó la escala de agencia y empoderamiento a través de un análisis factorial exploratorio, con una estructura de cuatro factores que explican el 44.6 % de la varianza. A su vez, la correlación de las subdimensiones de Grit-S y la escala de agencia y empoderamiento son positivas. Conclusiones: La prueba Grit-S es válida y sensible a dimensiones de funcionamiento individual, por la convergencia con las subdime0nsiones de agencia y la baja relación con el empoderamiento social.

Introduction: Grit is a construct that can predict performance in different domains. This research aims to provide evidence about the validity of the Grit-S Scale through a factorial structure confirmatory analysis and a convergence study with the Scale to Measure Personal Agency and Empowerment. Method: Firstly, university students from virtual learning programs (n = 313) answered the Grit-S Scale, and a confirmatory analysis was performed. Afterwards, the Scale to measure personal agency and empowerment was used to evaluate the convergence validity of the Grit-S Scale. Results: Findings confirm that the Grit-S scale has a bifactorial structure. On the other hand, the ESAGE Scale was adapted using an Exploratory Factorial Analysis, with four factors that explain 44.6% of the variance. Correlations between Grit-S subdimensions and the ESAGE Scale are positive and statistically significant. Conclusions: The Grit-S scale accurately measures Grit. Besides, it is possible to confirm the relationship between Grit and personality traits considering its convergence with the agency dimension in the Scale to measure personal agency and the low relationship with the social empowerment dimension.

Passion and perseverance: How the components of grit affect the probability of starting a business.

There is vast evidence that accounts for the association between entrepreneurial orientation (EO) and the probability of starting a business (PSB). However, there are not many studies that test how psychological factors moderate this relationship. A variable that has been little studied in this relationship is Grit. Grit is considered a personality trait defined as perseverance and passion for long-term goals. Grit considers two sub-dimensions, one linked to the consistency of interests (Grit-Passion) and the other linked to perseverance in the effort (Grit-Perseverance). The objective of this article is to analyze the moderating role that both sub-dimensions of grit plays in the relationship between EO and PSB, considering its interaction with sociodemographic variables such as age, gender, and culture. This cross-sectional study has a sample of 1,761 participants, active workers (49.8% men; mean age 41.15 years, SD = 12.72 years; 22.9% Colombian and 77.1% Spanish). The EO scale and a Grit Scale were applied. In addition, participants were asked, based on their perception, how likely they were to start their own business within the next 5 years. A simple moderation analysis was considered to test the moderating role of grit in the relationship between EO and PSB. Subsequently, a double moderation analysis was carried out in order to identify which sociodemographic variables moderate the moderating effect of grit on the relationship in question. The results show that only the Grit-Passion component of grit moderates the relationship between EO and PSB. Regarding the sociodemographic variables, neither age, culture, nor gender showed a moderating effect on the moderation exercised by Grit-Passion in the relationship between OE and PSB. The results are discussed in terms of psychological capital, particularly with an emphasis on explaining why only the Grit-Passion shows a moderating effect on the relationship between EO and PSB, in detriment of Grit-Perseverance. In addition, the power of grit in the field of entrepreneurship is discussed, considering that its moderating effect is transversal to variations in age, gender and culture, as well as its relevance when considering interventions and pedagogical models in the field of entrepreneurship.

Effects of Risk Factors on Belizean Adolescents' Academic Behaviors and Grit after Prolonged Absence During the COVID-19 Pandemic.

This causal-comparative study explored the effects of risk factors-family status, parental marital status, family income, and parent education level-on Belizean adolescents' academic behaviors and grit (passion and perseverance in goal achievement) following prolonged absence during the COVID-19 pandemic. Data were collected online using a demographic survey, the Grit-S Scale (Duckworth & Quinn, 2009), coupled with eight additional items to measure academic behaviors (attendance, preparedness, attention, note-taking, participation, organization, use of out-of-school time, and homework completion and submission) for success (Farrington et al., 2012) from secondary and tertiary students in Belize. With rare exception, Belizean education took place in person before the pandemic. This changed to remote teaching and learning during the pandemic. Findings showed that adolescents from the defined risk factor of single-parent households experienced greater declines across all eight academic behaviors. Additionally, this effect was more pronounced for adolescents who experienced the loss of a parent from divorce or death of a parent. For grit, there were two key outcomes: (a) adolescents from nuclear and higher income families had slightly higher levels of grit; and (b) adolescents from parents with lower educational attainment had significantly higher levels of grit than their peers. Based on these findings, recommendations include more study of schools that invest in becoming trauma responsive when evaluating engagement and performance during prolonged absences. Future research should assess adolescents' level of academic behaviors, grit, and other noncognitive factors.

Validación de la estructura psicométrica de las escalas Grit-O y Grit-S en el contexto colombiano y su relación con el éxito académico / Validation of the psychometric structure of the Grit-O and Grit-S scales in the Colombian context, and its relation with academic success

Resumen Dentro de los constructos que se han estudiado en los últimos años como predictores del desempeño académico se encuentra el factor grit. En la presente investigación se realizaron dos estudios con el objetivo de adaptar y validar la escala Grit-O a un contexto colombiano, así como determinar la validez de criterio de la escala Grit-S por medio del desempeño académico en estudiantes universitarios. En el primer estudio (n = 500) se realizó un análisis factorial exploratorio a través de un método de extracción de mínimos cuadrados no ponderados y un análisis factorial confirmatorio a través de un método de extracción de máxima verosimilitud. Los análisis arrojaron adecuados índices de validez y confiabilidad para las dos escalas (Grit-O y Grit-S) -siendo Grit-S la que presentó mejores índices de ajuste-, y la distribución de ítems por factor de la escala coincidió con la validación original. Sin embargo, los dos factores -perseverancia en el esfuerzo y consistencia en el interés- no se agruparon bajo el constructo grit. En el segundo estudio (n = 89) se observó la relación existente entre la puntuación obtenida en la escala Grit-S y diferentes indicadores de desempeño académico -promedio, número de materias perdidas, entre otros-. Para esto, se realizó un análisis de correlación y de regresión lineal múltiple, tras lo cual se encontraron correlaciones moderadas entre el puntaje total de la escala Grit-S y sus dos componentes con las medidas de desempeño académico. En el análisis de regresión se encontró que el puntaje total de la escala es mejor predictor del desempeño académico (.016**) que el puntaje de cada uno de los componentes de la escala por separado. Al final, en la discusión se comparan los hallazgos con validaciones realizadas en otros países y se dan algunas recomendaciones respecto al uso de la escala.

Abstract One of the constructs that have been studied in recent years as predictors of academic performance is the grit factor. In the present research, two studies were conducted with the aim of adapting and validating the Grit-O scale to a Colombian context, as well as determining the Grit-S scale's criterion validity by means of academic performance in university students. In the first study (n=500), an exploratory factor analysis was performed using an Unweighted Least Squares Extraction Method and a confirmatory factor analysis through a maximum likelihood extraction method. The analysis yielded adequate validity and reliability indexes for the two scales (Grit-O and Grit-S) -Grit- S being the one with the best fit indexes-, and the distribution of items per scale factor coincided with the original validation. However, the two factors (perseverance of effort and consistency of interest) were not grouped under the grit construct. In the second study (n=89), the relationship between the score obtained on the Grit-S scale and different academic performance indicators (grade point average, number of failed subjects, among others) was observed. For this purpose, a correlation and multiple linear regression analysis was performed. Findings show moderate correlations between the Grit-S scale total score and its two components, with the measures of academic performance. In the regression analysis, the total score was found to be a better predictor of academic performance (0.016 **) than the score of each of the scale components separately. Finally, the discussion compares the findings with validations carried out in other countries and gives some recommendations regarding the use of the grit scale.

Grit, Self-Efficacy, Motivation and the Readiness to Change Index Toward Exercise in the Adult Population.

This study examined the relationships between grit personality, self-efficacy, motivation (autonomous, controlled, and amotivation), and the readiness to change index toward exercise. Participants were 391 adults aged between 18 and 64 years old (M = 31.16; SD = 12.45) from Hermosillo, Sonora (Mexico) who completed questionnaires (i.e., the Grit Personality Scale, the Exercise Self-Efficacy Questionnaire, the Treatment Self-Regulation Questionnaire and the Stages of Change Questionnaire for Physical Activity) measuring the variables of interest. The reliability of the instruments was tested using Cronbach's alpha, whereas confirmatory factor analyses were performed for each instrument separately. A measurement model and a structural equation model were assessed as well. The results of the structural equations model showed that grit personality was positively associated with self-efficacy, and in turn, with autonomous motivation and with the readiness to change index. On the other hand, self-efficacy was negatively correlated with controlled motivation, and positively correlated with the readiness to change index. Finally, self-efficacy also showed a negative correlation with amotivation, which, in turn, was negatively correlated with the readiness to change index. These results provide information to develop psychological intervention programs based on grit personality and motivation, with the aim of increasing the number of participants who engage in exercise.

Surgical education in the COVID-19 era: What did the General Surgery Residents' report in Argentina leave us? Part 1.

Social distancing to curb the COVID-19 pandemic has impacted medical and surgical education. This health crisis led us to raise doubts, controversies, and dilemmas in health care in general, and in surgery in particular, understanding that residents are possibly as or more vulnerable than all health professionals. During the 32nd International Congress of General Surgery in Cordoba, which was the first general surgery congress held in Argentina during 2021; The Association of Residents and Concurrent Surgery of Córdoba presented its official report about the current challenges faced by residents during their surgical training.

Taking critical thinking, creativity and grit online.

Technology has the potential to facilitate the development of higher-order thinking skills in learning. There has been a rush towards online learning by education systems during COVID-19; this can therefore be seen as an opportunity to develop students' higher-order thinking skills. In this short report we show how critical thinking and creativity can be developed in an online context, as well as highlighting the importance of grit. We also suggest the importance of heuristic evaluation in the design of online systems to support twenty-first century learning.

Distinct Routes to Understand the Relationship Between Dispositional Optimism and Life Satisfaction: Self-Control and Grit, Positive Affect, Gratitude, and Meaning in Life.

Over the last years, understanding the implications of prospective thinking toward the future has become of increasing interest. This study aims to delve into the relation between dispositional optimism, one of the most relevant prospective constructs, and life satisfaction. Additionally, we also seek to prove the mediating effect of different cognitive and affective variables associated with both hedonic and eudaimonic well-being on this relationship. A first study is conducted with 275 secondary students to assess the relationship between optimism and life satisfaction through self-control and grit (14.82, SD = 1.07), which indicates a mediating effect of grit but not of self-control. A second study is carried out with 1,356 university students (21.5, SD = 2.35) to demonstrate the mediating effect of positive affect on dispositional optimism and life satisfaction. Results show a strong relationship between optimism and positive affect, but no mediating effect on life satisfaction. Finally, a third study comprising 371 secondary students (14.12, SD = 1.78) demonstrates the existence of a serial multiple mediation from gratitude and meaning in life over the relationship between optimism and life satisfaction. Implications are discussed in terms of how prospective variables like dispositional optimism may lead to an increase in subjective well-being (SWB) through different affective and cognitive mechanisms.

The influence of different surface treatment protocols and bonding agents on the repair microtensile bond strength of six-month' aged composite: An in vitro study / A influência de diferentes protocolos de tratamento de superfície e agentes de união na resistência de união à microtração de reparo de compósito envelhecido por seis meses: um estudo in vitro

Objective: To compare the effect of three surface treatment protocols and two intermediate agents on repairing aged composite, regarding microtensile bond strength (µTBS) and mode of fracture, at two time intervals. Material and methods: Six-monthaged microhybrid composite blocks, were randomly distributed into three groups, subjected to; Fine, Super Fine grit diamond burs or Erbium- Yag Laser surface treatment. Each block had both One Coat bond SL (Bond) and Brilliant Flow flowable composite (Flow) intermediate agents, alongside. Blocks were incrementally repaired using nanohybrid composite, cut into beams, then randomly subjected either immediately (IM) to µTBS test or after thermocycling (TC) for 5000 cycle. Mode of failure was determined using stereomicroscope. Data were analyzed through three-way ANOVA followed by pairwise comparison with Bonferroni correction. Kruskal Wallis test compared groups for failure mode analysis (α=0.05) Results: Super Fine grit showed the highest mean µTBScompared to control for both intermediate agents, IM and after TC at P<0.05. No difference between Fine grit and Laser application for all groups (P>0.05). IM, Bond showed the highest µTBS compared to TC, Flow for all tested groups. Beams roughened with Fine and Super Fine burs showed significantly lower adhesive failures than those roughened with Laser. Flow suffers significantly higher adhesive failure than those with Bond. For TC tested groups; beams with Super Fine bur and Bond showed significantly lower adhesive failure at P=0.029. Conclusion: Super Fine grit and Bond provide the highest µTBS and the least adhesive failure; moreover TC resulted in significant decrease in µTBS (AU)

Objetivo: Comparar o efeito de três protocolos de tratamento de superfície e dois agentes intermediários no reparo de compósito envelhecido, quanto à resistência à microtração (µTBS) e modo de fratura, em dois intervalos de tempo. Material e métodos: Blocos de compósito microhíbrido envelhecidos por seis meses, foram distribuídos aleatoriamente em três grupos, submetidos a; Pontas diamantadas de granulação Fina, Superfina ou tratamento de superfície com laser de Erbio-Yag. Cada bloco tinha ambos os agentes intermediários One Coat bond SL (Adesivo) ao lado de Brilliant Flow (Resina Fluida). Os blocos foram reparados de forma incremental usando compósito nanohíbrido, cortados em palitose, em seguida, submetidos aleatoriamente imediatamente (IM) ao teste de µTBS ou após termociclagem (TC) por 5000 ciclos. O modo de falha foi determinado usando estereomicroscópio. Os dados foram analisados por meio de ANOVA de três fatores, seguida de comparação pareada com correção de Bonferroni. O teste de Kruskal Wallis comparou os grupos para análise do modo de falha (α = 0,05). Resultados: a granulação Super fina apresentou a maior média de µTBS em comparação com o controle para ambos os agentes intermediários, IM e após TC (P <0,05). Não houve diferença entre granulação fina e aplicação de laser para todos os grupos (P> 0,05). IM, Adesivo apresentou a µTBS mais alta em comparação com TC, Resina Fluida para todos os grupos testados. Os palitos asperizados com pontas de granulações Fina e Superfina apresentaram falhas adesivas significativamente menores do que as asperizadas com Laser. Resina Fluida sofreu falhas adesivas significativamente maiores do que aquelas com Adesivo. Para grupos testados TC; palitos tratados com ponta Superfina e Adesivo apresentaram falha adesiva significativamente menor com P = 0,029. Conclusão: a granulação Superfina e o Adesivo fornecem a maior µTBS e o mínimo de falha adesiva; além disso, o TC resultou em uma diminuição significativa da µTBS. (AU)

Validation of the Grit Scale and the Treatment Self-Regulation Questionnaire (TSRQ) in the Mexican context / Validación de la escala Grit y del Cuestionario de Autorregulación del Tratamiento (TSRQ) al contexto mexicano

Abstract The lack of valid tools to measure variables related to healthy behaviors in Mexico has led the authors to adapt and validate the Grit Scale and the Treatment Self-Regulation Questionnaire (TSRQ) for diet into Mexican Spanish, and explore the relationship between grit and types of motivation towards healthy eating as evidence of validity. The Grit Scale and the TSRQ in Spanish were put to 353 adults from the state of Nuevo León, Mexico. The Grit Scale was composed of 12 items distributed into two factors (consistency of interest and perseverance of effort), and the TSRQ for diet was composed of 15 items distributed into three factors (autonomous motivation, controlled motivation, and amotivation). Results showed acceptable fit indices for the long and short versions of the Grit Scale, confirming its two-factor structure. In addition, acceptable fit indices were found for the TSRQ for diet, indicating the presence of three latent factors. Significant and positive relationships were found between grit and autonomous motivation, and negative relationships with controlled and amotivation. The analyses carried out indicated that the instruments administrated are valid and reliable tools for use in Mexico.

Resumen La ausencia de instrumentos válidos para medir variables relacionadas con las conductas saludables en México, nos lleva al objetivo de adaptar y validar al idioma español hablado en México la escala Grit y el cuestionario de autorregulación del tratamiento (TSRQ) de la dieta, y explorar la relación entre el Grit y la motivación hacia la alimentación saludable como evidencia de validez. 353 adultos del estado de Nuevo León respondieron a la escala Grit adaptada al español conformada por 12 ítems distribuidos en dos factores (consistencia del interés y perseverancia del esfuerzo) y al TSRQ adaptada al español compuesto por 15 ítems en tres factores (motivación autónoma, motivación controlada y no motivación). Los resultados mostraron índices de ajuste aceptables para la versión larga y corta de la escala Grit confirmando su estructura bifactorial. Además, se encontraron índices de ajuste aceptables para el TSRQ de la dieta indicando la presencia de tres factores latentes. Se observaron relaciones significativas y positivas entre el Grit y la motivación autónoma, y de manera negativa con la motivación controlada y no motivación. Los análisis realizados indican que los instrumentos administrados son herramientas válidas y confiables para ser utilizadas en México.

Midday napping in children: associations between nap frequency and duration across cognitive, positive psychological well-being, behavioral, and metabolic health outcomes.

STUDY OBJECTIVES: Poor sleep and daytime sleepiness in children and adolescents have short- and long-term consequences on various aspects of health. Midday napping may be a useful strategy to reduce such negative impacts. The effect of habitual napping on a wide spectrum of cognitive, behavioral, psychological, and metabolic outcomes has not been systematically investigated. METHODS: This study characterized midday napping habits in 3819 elementary school children from the China Jintan Cohort Study. In 2011, weekly nap frequency and average duration were collected once from students at grades 4-6. Prior to their completion of elementary school at grade 6 (in 2011-2013 respective to each grade), the following outcomes were collected once: behavioral and academic achievement evaluated by teachers, and self-reported positive psychology measures including grit, self-control, and happiness. IQ tests were conducted on a subgroup. Metabolic indices, including body mass index and fasting glucose concentration, were measured through physical exams. For the whole sample, we assessed associations between napping and each outcome, adjusted for sex, grade, school location, parental education, and time in bed at night. We also conducted stratified analyses on grade 6 (cross-sectional), grade 4 (2-year gap), and grade 5 (1-year gap) data. RESULTS: Overall, napping was significantly associated with higher happiness, grit, and self-control, reduced internalizing behavior problem, higher verbal IQs, and better academic achievement, although specific patterns varied across frequency and duration for different outcomes. More limited significant associations were found for decreased externalizing behavior problems, compared to non-nappers, while no significant associations were found for performance IQ and metabolic outcomes. CONCLUSIONS: Results indicate benefits of regular napping across a wide range of adolescent outcomes, including better cognition, better psychological wellness, and reduced emotional/behavioral problems. The current study underscores the need for further large-scale intervention studies to establish causal effects.

Tenacidad en estudiantes universitarios chilenos: Un estudio inicial de su estructura y red nomológica / Grit in Chilean university students: An initial study of its structure and nomological network

En los últimos años ha surgido un creciente interés por indagar el rol de las habilidades no cognitivas, como la tenacidad, en el desempeño académico. Si bien la investigación sobre tenacidad no ha generado aún conclusiones definitivas, debe considerarse que ella no ha incluido a poblaciones latinoamericanas. Ante este panorama, este estudio inicial se propuso examinar en estudiantes universitarios chilenos de pedagogía en matemáticas: (1) la estructura interna de la tenacidad y (2) su posición en una red nomológica integrada por desempeño académico, sexo, edad y años en el programa educativo. Un total de 153 estudiantes de la Universidad de La Frontera, una institución estatal chilena, respondió la Escala Corta de Tenacidad y un cuestionario sociodemográfico. Análisis factoriales exploratorios revelaron que la tenacidad adquiere una configuración unidimensional que posee una adecuada consistencia interna. Además, adoptando una relación no lineal semejante a una curva hiperbólica, niveles altos de tenacidad se vincularon con desempeño académico alto, en tanto que niveles bajos o moderados se vincularon con desempeño bajo. Finalmente, la tenacidad apareció asociada con sexo (las mujeres mostraron más tenacidad que los hombres) y, en una relación directa, con los años en el programa. Tenacidad no correlacionó significativamente con edad. Este conjunto de hallazgos, que discrepan mayormente de aquellos reportados en la literatura, son discutidos principalmente en términos del dominio disciplinar previo de los participantes y/o de la dificultad del programa educativo. Se proponen explicaciones para estos hallazgos a fin de que sean evaluadas en estudios futuros, empleando un enfoque confirmatorio.

Traditionally, academic performance has been linked to intelligence and some other student´s cognitive abilities. However, in recent 4 years we have witnessed a growing interest in expanding this view by investigating the role that other non-cognitive skills, such as tenacity, may play in academic achievement. Grit can conceptually be conceived as perseverance and passion aimed at achieving long-term goals. A review of the literature shows that grit does not appear to be configured, as some authors claim, as a hierarchical structure with a general second-order construct and two first-order facets (perseverance of effort and consistency of interest). The literature also points out that grit is only a modest predictor of academic performance and that it presents a slightly positive correlation with age and a very weak one with sex and the students' number of years in an academic program. While research on grit has not yet generated any definitive conclusions, it must be considered that it has not included Latin American populations. Given this scenario, this initial study aimed to examine in mathematics teacher Chilean students (1) the internal structure of grit and (2) their position in a nomological network integrated by academic achievement, sex, age and years enrolled in the program. Participants consisted in the total population (n = 153) of students enrolled in a mathematics teacher program at Universidad de La Frontera, a public institution located in the Central-South area from Chile. The program was selected because it presents a high level of difficulty to its students and because it includes highly formalized tasks, as part of its disciplinary courses. Participants responded the Short Grit Scale (Grit-S) and a demographic questionnaire. In this study, Grit-Swas previously translated and adapted into Spanish from the original English version. Grit-Scontains eight items intended to measure the two facets of grit. Exploratory factorial analysis revealed that, after excluding two items due to low factor loadings (items No. 1 and 2), grit presented a one-dimensional configuration, with an adequate internal consistency (ordinal Alpha: .80). A positive linear correlation, although marginally significant, was obtained between grit and academic achievement, r(143)= .12, p =.069, d = .24. However, a planned contrast revealed that a nonlinear relationship, similar to a hyperbolic curve, better explains the link between these two variables. Specifically, this analysis showed that students in the upper grit quintile obtained a significantly higher grade point average than the combined grade point average of the remaining grit quintiles, t(138) =1.87, p = .032, d = .32. This result suggests that academic achievement remains reduced when grit level is low or moderate and only increases when grit level is high. A multiple regression analysis indicated that sex, age and number of years in the program account for 12.6% of grit variance, F(3, 149) = 7.15, p < .001, d = .76. Sex significantly contributed to the prediction (β =.198, p = .011, d = .38) with women, (M = 3.77,dt = .61) reporting higher levels of grit than men (M = 3.53, dt = .69). Whereas age did not significantly contribute to the prediction (β =.102, p = .206), the number of years in the program showed a significant direct association with grit (β = .261, p = .001, d = .60. Due to the originality of these findings, most differing from those reported in the literature, this study offers tentative explanations that future research could use to formulate and empirically test new hypotheses using, hopefully, a confirmatory approach. These possible explanations mainly refer to the participants' previous level of mathematic mastery and/or the level of difficulty demanded by the educational program.

The Role of Self-control and Grit in Domains of School Success in Students of Primary and Secondary School.

Objective: Self-control and grit have become two of the most important variables that explain success in different aspects of people's daily life (Duckworth and Gross, 2014). Self-control promotes delayed gratification and directly influences thoughts, emotions, and impulses. On the other hand, grit enhances the achievement of goals through perseverance even before extreme external circumstances. Since both constructs are related, examining them together is compelling, as long as the different nuances that characterize each are taken into account. Two structural equation models (SEM) were conducted to observe the effect of self-control and grit on a more specific indicator of academic success (academic self-efficacy) and a more general indicator of school experience (satisfaction with school). Methods: The first model comprises 5,681 primary students (M = 9.05; SD = 0.79), and the second 10,017 secondary students (M = 14.20; SD = 1.04) from Lima, Peru. In both models, the influence of grit and self-control on school satisfaction was observed when taking self-efficacy as a mediator variable. Results: The results show that grit and self-control have strong associations in both primary and secondary students. When estimating the covariance of both constructs, grit is related with academic-self efficacy at both educational stages, but only to satisfaction with school in secondary students. On the contrary, self-control shows a significant relationship with school satisfaction only in primary education. In turn, self-efficacy shows a mediating effect between grit and school satisfaction. After calculating the invariance of the models, differences are observed by gender in the relationships between variables. Conclusion: The results indicate that both constructs are strongly interrelated. Regarding the associations with the indicators of academic success, a need for timely interventions specific to each educational stage is observed.

Significance of the contacting and no contacting thermoelectric power measurements applied to grit blasted medical Ti6Al4V.

Grit blasting is a surface plastic deformation technique aimed to increase the surface area available for bone/implant apposition, which contributes to improve fixation and mechanical stability of Ti-6Al-4V implants. Besides roughening, grit blasting also causes surface contamination with embedded grit particles and subtle subsurface microstructural changes that, although does not challenge their biocompatibility, might influence other surface dominated properties like corrosion and ion release. Additional benefits are expected due to the induced compressive residual stresses, hence enhancing fatigue strength. The net effect depends on the type of particles used for blasting, but also on the amount of the subsurface cold work associated to the severe surface plastic deformation. In this work we study the potential of the non-contacting and contacting thermoelectric power (TEP) measurements in the analysis of the global changes induced in the Ti6Al4V when blasting the alloy with Al2O3 or ZrO2 particles, which yields a coarse and a fine rough surface, respectively. To reveal the effect of residual stresses, a set of specimens were thermally treated. The study proves that the non-contacting technique is more sensitive to the presence of residual stresses, whereas the contact technique is strongly influenced by the grain size refinements, work hardening and changes in solute.

Determinação da quantidade de areia no esgoto sanitário: metodologia e estudo de caso / Determination of grit quantity in wastewater: methodology and case study

Apesar de os desarenadores serem largamente utilizados, há mais de um século, como uma das unidades que compõem o tratamento preliminar de estações de tratamento de esgoto (ETEs), pouco se sabe a respeito de suas eficiências de remoção devido à total carência de métodos analíticos padronizados para determinação da concentração de areia presente no esgoto sanitário. O presente artigo apresenta um método original para determinação da concentração de areia no esgoto, baseado no emprego de procedimentos amplamente conhecidos, como: sedimentação em cones Imhoff, oxidação com peróxido de hidrogênio, enxágües sucessivos, calcinação e pesagem em ba-lança analítica. A aplicação do método desenvolvido demonstrou que a concentração de areia no esgoto sanitário afluente da ETE Jardim das Flores (Rio Claro, SP) apresenta grande variabilidade com picos de até 200 mg/l e que a concentração média de areia encontra-se entre 20 mg/l e 73 mg/l.

Although degritters have been largely used, for more than a century, as preliminary treatment units of wastewater treatment plants (WWTP), their removal efficiency is yet poorly known due to the lack of standardized analytical methods to determine wastewater grit concentration. This paper brings up this subject and presents an original method to determine wastewater grit concentration based on use of well-known procedures, such as: Imhoff cone sedimentation, hydrogen peroxide oxidation, sequential rinse, calcination and analytical balance weighing. The application of the developed method demonstrated that grit concentration in the influent of WWTP Jardim das Flores varies significantly, with peak concentration of about 200 mg/l, and that the mean grit concentration seems to be among 20 mg/l and 73 mg/l.