Time of Day and Sleep Deprivation Effects on Risky Decision Making.

Previous research has revealed that daily variations in human neurobehavioral functions are driven in part by the endogenous circadian system. The objective of this study was to explore whether there exists a circadian influence on performance regarding a risky decision-making task and to determine whether the performance changes with sleep deprivation (SD). Thirteen participants underwent a 39 h constant routine (CR) protocol, during which they remained awake in constant conditions and performed the BART (balloon analogue risk task) every two hours. The mean pumps (gains) (p < 0.001) and balloons popped (losses) (p = 0.003) exhibited variation during the CR. The reaction time (RT) also showed significant variation across the CR (p < 0.001), with slower mean RTs in the morning hours following SD. A greater risk propensity was observed around midday before SD and a lower risk propensity after 29.5 h of being awake. The sensitivity to punishment varied during the CR, but did not follow a predictable trend. Further research using real monetary incentives and neurophysiological measures is warranted to elucidate these findings.

The Impact of the Double School Shift System on Lifestyle Behaviors Among Mexican Adolescents.

PURPOSE: Early school start times could adversely impact adolescent sleep duration. They could also impact other behaviors like diet and physical activity, either directly or indirectly through effects on sleep. We examined whether the double school shift system was associated with sleep, diet, and physical activity behaviors among Mexican adolescents. METHODS: The analytic sample included 305 Mexican adolescents from a cohort study (on average 14.53 ± 1.75 years old and 51% male). Sleep and physical activity were measured with wrist actigraphy, while diet and other lifestyle behaviors were assessed with questionnaires. Regression analyses were conducted to compare lifestyle behaviors between the morning and afternoon school shifts, adjusting for potential confounders. RESULTS: Adolescents attending the morning school shift (44%) had pronounced differences in sleep compared to those attending afternoon shift, including a 1.77-hour shorter sleep duration on weekdays (95% CI -1.55, -2.00), a 0.40-hour longer sleep duration on weekends (95% CI 0.10, 0.70), higher social jetlag (1.07 hours with a 95% CI of 0.87, 1.27), and an earlier chronotype. Morning shift students also had 0.85 hours longer sedentary time (95% CI 0.61, 1.10) and higher consumption of a meat and starchy food dietary pattern. Among boys only, morning shift was associated with a lower likelihood of smoking and higher consumption of a breakfast pattern. DISCUSSION: Overall, attending a morning school shift was associated with shorter sleep, more social jetlag, greater sedentary time, and higher consumption of a meat and starchy diet. However, among boys, a few healthier behaviors were observed for the morning versus afternoon shift.

Circadian protein expression patterns in healthy young adults.

OBJECTIVES: To explore how the blood plasma proteome fluctuates across the 24-hour day and identify a subset of proteins that show endogenous circadian rhythmicity. METHODS: Plasma samples from 17 healthy adults were collected hourly under controlled conditions designed to unmask endogenous circadian rhythmicity; in a subset of 8 participants, we also collected samples across a day on a typical sleep-wake schedule. A total of 6916 proteins were analyzed from each sample using the SomaScan aptamer-based multiplexed platform. We used differential rhythmicity analysis based on a cosinor model with mixed effects to identify a subset of proteins that showed circadian rhythmicity in their abundance. RESULTS: One thousand and sixty-three (15%) proteins exhibited significant daily rhythmicity. Of those, 431 (6.2%) proteins displayed consistent endogenous circadian rhythms on both a sleep-wake schedule and under controlled conditions: it included both known and novel proteins. When models were fitted with two harmonics, an additional 259 (3.7%) proteins exhibited significant endogenous circadian rhythmicity, indicating that some rhythmic proteins cannot be solely captured by a simple sinusoidal model. Overall, we found that the largest number of proteins had their peak levels in the late afternoon/evening, with another smaller group peaking in the early morning. CONCLUSIONS: This study reveals that hundreds of plasma proteins exhibit endogenous circadian rhythmicity in humans. Future analyses will likely reveal novel physiological pathways regulated by circadian clocks and pave the way for improved diagnosis and treatment for patients with circadian disorders and other pathologies. It will also advance efforts to include knowledge about time-of-day, thereby incorporating circadian medicine into personalized medicine.

The Timing of the Melatonin Onset and Phase Angle to Sleep Onset in Older Adults after Uncontrolled vs. Controlled Lighting Conditions.

The main aim of this study was to explore how melatonin onset timing and phase angle to bedtime in healthy older adults are impacted by prior light exposure. A total of 13 healthy older (ages 56-74) individuals were studied on two successive evenings. Prior to the first evening, the participants were in self-selected lighting conditions for the first 4-6 h of the day and then were in dim light (3 lux) until their scheduled bedtime. On the second day, individuals from Project A remained in the dim lighting conditions throughout the entire day but those in Project B were in more typical indoor lighting (~90 lux) throughout the day. On both evenings, hourly blood samples were collected and assayed for melatonin, and melatonin onset timing and phase angle to sleep onset was determined. Overall, melatonin onset was earlier and the phase angle was larger on Night 1 than on Night 2. In Project A there was no significant difference between melatonin onset on night 1 vs. night 2. However, in Project B melatonin onset was significantly later on Night 2 (in typical indoor lighting) than on Night 1 (in dim lighting). Our results suggest that in older people, uncontrolled bright light early in the day did not impact the timing of dim light melatonin onset (DLMO) when assessed later that same evening. However, in older adults, exposure to ordinary room light during melatonin phase assessment appeared to suppress melatonin, leading to a later observed time of melatonin onset, as has been reported previously for young adults.

The influence of a permanent double-shift school start time on adolescent sleep and chronotype across different age groups.

The main objective of this study was to explore the differences in sleep habits and chronotype across different age groups in Mexican adolescents attending a permanent double-shift school system. This cross-sectional study consisted of 1,969 (1,084 girls) students from public elementary, secondary, and high schools, as well as undergraduate university students from Mexico. Age range was 10-22 [15.33 ± 3.28 (mean ± SD)] years, 988 morning shift and 981 afternoon shift students. Questions regarding usual self-reported bedtime and rise time were collected, and from that, estimates for time in bed, midpoint of sleep, social jetlag, and chronotype were evaluated. Afternoon shift students reported later rise times, bedtimes, midpoint of sleep, and longer time in bed on school days than morning shift students, as well as less social jetlag. Overall, afternoon shift students reported a later chronotype than morning shift students. Peak lateness of chronotype in afternoon shift students was at age 15, with girls peaking at age 14 and boys at age 15. Meanwhile, morning shift students reported peak lateness of chronotype around age 20. In this study, adolescents from different age ranges attending an extremely delayed school start time reported adequate sleep compared with adolescents attending a fixed morning school start time. In addition, the analysis presented in this study seems to suggest that the peak of late chronotype may be influenced by school start times.

Impact of digital technologies upon teaching and learning in higher education in Latin America: an outlook on the reach, barriers, and bottlenecks.

Digital technology and literacy can heighten the transformation of teaching and learning in higher education institutions (HEIs). This study uncovers the extent to which digital technologies have been used to advance the teaching and learning process in HEIs, and the barriers and bottlenecks to why it may not have been effectively implemented across the HEIs. The study used nine selected countries in Latin America (LATAM) based on the main focus of the educators, commercial, and financial investors; to show the level of impact/implications of computer technologies on the teaching and learning processes. We applied a two-step (mixed) methodology (through a quantitative and qualitative lens) for the research investigation, using data collected from survey we administered to faculty members in HEIs across the different countries in LATAM. In turn, we implemented a Text Mining technique (sentiment and emotional valence analysis) to analyze opinions (textual data) given by the participants to help determine challenges and obstacles to using the digital technologies for teaching and learning in the region. Quantitatively, we applied a Kruskal-Wallis H-test to analyze the collected multiple choice and ranked items in the questionnaire in order to identify prominent factors that consummately influence the reach, barriers, and bottlenecks, and where the differences may lie across the different LATAM countries. The results show that the users upheld the emphasis on lack of training, infrastructures and resources, access to internet and digital platforms, as the main challenges to the teaching-learning process. The study also empirically discussed and shed light on critical factors the HEIs, particularly in LATAM, should resolve and adopt in support of the decision-making strategies, operational policies and governance, financial investments, and policymaking, at a time when "digital technologies" have become an inevitable and indispensable part of education and learning.

Effects of COVID-19 lockdown on sleep duration, sleep quality and burnout in faculty members of higher education in Mexico / Efeitos do lockdown da COVID-19 na duração e qualidade do sono e sintomas de burnout no corpo docente do ensino superior no México

Abstract This paper aims to assess the differences and associations of the effect of COVID-19 on sleep habits, sleep quality, and burnout symptoms among faculty members of higher education in Mexico. This was a cross-sectional study with a total sample of 214 faculty members of higher education from Mexico between May 18th and June 10th of 2020. We applied questionnaires containing sociodemographic and specific questions regarding sleep habits, sleep quality, and burnout symptoms. The results show that during COVID-19 faculty members delayed their bedtime and rise time. No change was found with weekdays time in bed, however, during weekends, time in bed was more than an hour shorter. Social jetlag decreased significantly during COVID-19. Furthermore, during COVID-19, those who reported low sleep quality were more likely to report higher symptoms of emotional exhaustion and those who slept less on weekends were more likely to report higher symptoms of depersonalization. These results suggest that the COVID-19 pandemic may have an effect on sleep and sleep quality and burnout symptoms of faculty members from higher education in Mexico.

Resumo Este trabalho visa avaliar as diferenças e associações do impacto da COVID-19 sobre hábitos de sono, qualidade do sono e sintomas de burnout entre os docentes de ensino superior no México. Trata-se de um estudo transversal, com amostra total de 214 docentes, realizado entre 18 de maio e 10 de junho de 2020. Foram aplicados questionários contendo questões sociodemográficas e específicas sobre hábitos de sono, qualidade do sono e sintomas de burnout. Os resultados mostram que durante a pandemia os docentes atrasaram a hora de dormir e acordar. Nenhuma alteração foi observada com relação ao tempo de semana na cama, porém nos finais de semana o tempo na cama era mais de uma hora menor. O jetlag social diminuiu significativamente durante a COVID-19. Além disso, durante a pandemia, aqueles que relataram baixa qualidade do sono eram mais propensos a relatar sintomas mais fortes de exaustão emocional, e aqueles que dormiam menos nos fins de semana eram mais propensos a relatar sintomas mais fortes de despersonalização. Esses resultados sugerem que a pandemia de COVID-19 pode ter um efeito sobre a qualidade do sono e causar sintomas de burnout nos integrantes do corpo docente do ensino superior no México.

Effects of COVID-19 lockdown on sleep duration, sleep quality and burnout in faculty members of higher education in Mexico.

This paper aims to assess the differences and associations of the effect of COVID-19 on sleep habits, sleep quality, and burnout symptoms among faculty members of higher education in Mexico. This was a cross-sectional study with a total sample of 214 faculty members of higher education from Mexico between May 18th and June 10th of 2020. We applied questionnaires containing sociodemographic and specific questions regarding sleep habits, sleep quality, and burnout symptoms. The results show that during COVID-19 faculty members delayed their bedtime and rise time. No change was found with weekdays time in bed, however, during weekends, time in bed was more than an hour shorter. Social jetlag decreased significantly during COVID-19. Furthermore, during COVID-19, those who reported low sleep quality were more likely to report higher symptoms of emotional exhaustion and those who slept less on weekends were more likely to report higher symptoms of depersonalization. These results suggest that the COVID-19 pandemic may have an effect on sleep and sleep quality and burnout symptoms of faculty members from higher education in Mexico.

Association between self-reported sleep duration and dietary quality in Mexican school-aged children.

Short sleep duration has been associated with poor diet quality in school-aged children in multiple populations. However, investigations of sleep and dietary quality in Mexican school-aged children are scarce. The main objective of this work was to assess the association between sleep duration and dietary quality in Mexican school-aged children stratified by sex. The data were collected from 373 (138 girls and 235 boys) elementary school children aged 6-12 years in Monterrey, Nuevo Leon, Mexico. Surveys collected information on general demographic characteristics and self-reported sleep duration. Diet was assessed with 24-h recalls, and dietary quality was calculated by the Healthy Eating Index (HEI-2015). Results indicated that overall mean sleep duration was 8.23 ± 1.06 h. From the total sample, 6.7% slept ≤6 h (not recommended), 55.8% 7-8 h (may be appropriate), and 37.5% ≥ 9 h (recommended). Average total HEI-2015 score was 64.6 (out of possible 100), with boys having lower HEI-2015 scores than girls (57.7 vs 69.4). Moreover, girls and boys with shorter sleep duration (≤6 h compared to ≥ 9 h) had lower HEI-2015 scores (-1.03 [95% CI -2.74, -0.47; p < .01] and -1.78 [95% CI -3.15, -0.86; p < .001], respectively). Regarding the individual components of dietary quality, those with ≤6 h of sleep had lower scores particularly in vegetables, protein sources, added sugars and saturated fats for girls and boys compared to those with ≥9 h. These findings suggest sleep may be an important determinant of dietary practices within the Mexican children.

Towards teaching analytics: a contextual model for analysis of students' evaluation of teaching through text mining and machine learning classification.

Recent trends in educational technology have led to emergence of methods such as teaching analytics (TA) in understanding and management of the teaching-learning processes. Didactically, teaching analytics is one of the promising and emerging methods within the Education domain that have proved to be useful, towards scholastic ways to make use of substantial pieces of evidence drawn from educational data to improve the teaching-learning processes and quality of performance. For this purpose, this study proposed an educational process and data mining plus machine learning (EPDM + ML) model applied to contextually analyze the teachers' performances and recommendations based on data derived from students' evaluation of teaching (SET). The EPDM + ML model was designed and implemented based on amalgamation of the Text mining and Machine learning technologies that builds on the descriptive decision theory, which studies the rationality behind decisions the learners are disposed to make based on the textual data quantification and statistical analysis. To this effect, the study determines pedagogical factors that influences the students' recommendations for their teachers, what role the sentiment and emotions expressed by the students in the SET play in the way they evaluate the teachers by taking into account the gender of the teachers. This includes how to automatically predict what a student's recommendation for the teachers may be based on information about the students' gender, average sentiment, and emotional valence they have shown in the SET. Practically, we applied the Text mining technique to extract the different sentiments and emotions (intensities of the comments) expressed by the students in the SET, and then utilized the quantified data (average sentiment and emotional valence) to conduct an analysis of covariance and Kruskal Wallis Test to determine the influential factors, as well as, how the students' recommendation for the teachers differ by considering the gender constructs, respectively. While a large proportion of the comments that we analyzed (n = 85,378) was classified to be neutral and predominantly interpreted to be positive in nature considering the sentiments (76.4%), and emotional valence (88.2%) expressed by the students. The results of our analysis shows that for the students' comments which contain some kind of positive or negative sentiment (23.6%) and emotional valence (11.8%); that females students recommended the teachers taking into account the sentiments (p = .000). While the males appear to be slightly borderline in terms of emotions (p = .056) and sentiment (p = .077). Also, the EPDM + ML model showed to be a good predictor and efficient method in determining what the students' recommendation scores for the teachers would be, going by the high and acceptable values of the precision (1.00), recall (1.00), specificity (1.00), accuracy (1.00), F1-score (1.00) and zero error-rate (0.00) which we validated using the k-fold cross-validation method, with 63.6% of optimal k-values observed. In theory, we note that not only does the proposed method (EPDM + ML) proves to be useful towards effective analysis of SET and its implications within the educational domain. But can be utilized to determine prominent factors that influences the students' evaluation and recommendation of the teachers, as well as helps provide solutions to the ever-increasingly need to advance and support the teaching-learning processes and/or students' learning experiences in a rapidly changing educational environment or ecosystem.

Sleep and Depressive Symptoms in the Morningness/Eveningness-Suicidal Ideation Relationship Depend on School Shift in Mexican Adolescents.

The aim was to analyze the morningness/eveningness (M/E) effect on suicidal ideation through sleep and depressive symptoms mediators with school shift (i.e., morning and afternoon) as moderator. In this study, 586 Mexican adolescents, with a mean age of 16.31 ± 0.92, from a public high school in a double-shift school system (298 from the morning shift and 288 from the afternoon shift) participated. Measurements of sleep, morningness/eveningness (circadian preference), depressive symptomology, and suicidal ideation were completed. Adolescents in the afternoon shift reported a later rise time, bedtime, greater time in bed sleep length, and less social jet lag than in the morning shift. Considering the moderated-mediated analysis, circadian preference and suicidal ideation were mediated by both depressive symptoms and school day's sleep length in the morning shift. In the afternoon shift, no mediation effect was significant. When weekend sleep length was considered in the model, only depressive symptoms had a mediating effect between circadian preference and suicidal ideation in the morning shift; no significant mediating effect was found on the afternoon shift. The results suggest that an afternoon school schedule may act as a protective factor for the adolescent's mental health and may represent a viable option for future interventions.

Animal Welfare Attitudes: Effects of Gender and Diet in University Samples from 22 Countries.

Animal Welfare Attitudes (AWA) are defined as human attitudes towards the welfare of animals in different dimensions and settings. Demographic factors, such as age and gender are associated with AWA. The aim of this study was to assess gender differences among university students in a large convenience sample from twenty-two nations in AWA. A total of 7914 people participated in the study (5155 women, 2711 men, 48 diverse). Participants completed a questionnaire that collected demographic data, typical diet and responses to the Composite Respect for Animals Scale Short version (CRAS-S). In addition, we used a measure of gender empowerment from the Human Development Report. The largest variance in AWA was explained by diet, followed by country and gender. In terms of diet, 6385 participants reported to be omnivores, 296 as pescatarian, 637 ate a vegetarian diet and 434 were vegans (n = 162 without answer). Diet was related with CRAS-S scores; people with a vegan diet scored higher in AWA than omnivores. Women scored significantly higher on AWA than men. Furthermore, gender differences in AWA increased as gender inequality decreased.

Sleep habits and circadian preferences in school-aged children attending a Mexican double-shift school system.

OBJECTIVE: To determine the differences between sleep habits and circadian preference in school-aged children attending a Mexican double-shift school system. METHODS: This cross-sectional study consisted of 400 elementary public-school children (mean age = 10.77, SD = 0.70 y, from fourth, fifth and sixth grades) in Reynosa, Tamaulipas, in northeastern Mexico. Attending a double-shift school system: 200 from the morning shift and 200 in the afternoon shift. Specific questions regarding sleep habits were collected and for circadian preference, the Morningness-Eveningness Scale for Children (MESC) was used. RESULTS: Multivariate analysis reported no sex differences. Children attending at the morning shift during weekdays rose earlier, reported shorter time in bed and earlier midpoint of sleep than those in the afternoon shift. On weekends, morning shift children went to bed later than afternoon shift. Morning shift reported greater social jetlag, shorter average sleep length and more sleep deficit than afternoon shift. During weekdays and weekends evening type children went to bed later, rose later and reported later midpoint of sleep. Also, evening type reported more social jetlag than morning types. CONCLUSION: This study suggests that early school start times can have a detrimental effect on Mexican children. Moreover, the morning shift children may be at more risk of poor health due to the higher social jetlag, as well as a higher tendency to be sleep deprived. On the other hand, the afternoon shift represents an important social environment that allows children to follow their natural physiological needs and a more optimal sleep health.

Self-reported sleep duration, sleep quality and sleep problems in Mexicans adults: Results of the 2016 Mexican National Halfway Health and Nutrition Survey.

OBJECTIVE: This study aimed to investigate self-reported sleep duration, sleep quality and sleep problems in a Mexican adult population by considering age, sex, geographical regions and urban/rural residency. DESIGN/MEASUREMENTS: Cross-sectional national adult survey based on the 2016 Mexican National Halfway Health and Nutrition Survey data. SETTING: Nationally representative survey data. PARTICIPANTS: Mexican adults ≥ 18 years, n = 8649 (N weighted = 71,158,260 adults). RESULTS: Overall, mean sleep duration was 7:19 hours, from which 37% had sleep problems, and 45.7% reported very good sleep quality. Furthermore, middle-aged adults slept less than younger and older adults, females were at lower risk of being a short sleeper than males, urban residents slept less than rural residents, and those from the center region of the country slept less than from the northern and southern regions. Mainly, participants from the state of Quintana Roo, Aguascalientes, and Baja California reported sleep duration <7 hours (6:26 hours, 6:45 hours, and 6:55 hours, respectively). Overall Mexicans who obtained sufficient sleep (≥8 hours) were more likely to be female, in their 20s, reporting perceived "good" or "very good" sleep quality, possessed no self-reported sleep problems, were not a tobacco user, and resided in rural areas. Furthermore, Mexicans who obtained poor sleep quality were more likely to be females that reported sleep problems, took sleep medications, and resided in urban areas. CONCLUSION: The present study's findings have important implications for understanding the nationwide features of sleep in Mexican adults. Education and public health awareness initiatives regarding good sleep may be warranted.

Does professors' gender impact how students evaluate their teaching and the recommendations for the best professor?

This study examined the impact of the professors' gender according to a student evaluation of teaching (SET) in a private university. The study took place in a private university (n = 103,833) on six different campuses in the north region of Mexico. The distribution of the professors' gender was analyzed according to semesters, campuses, and schools. Our findings suggested that when undergraduates evaluated their professors on specific criteria concerning teaching performance, they expressed their opinion regardless of the professors' gender. However, when being asked for a single overall evaluation, as whether they would recommend the professor as one of their best professors, the students tended to favor male professors over their female peers by a slight margin. While such perceptions might not be representative of the actual teaching quality, it would be interesting in the future to delve deeper into the causes of possible biases.

Assessment of multiple intelligences in elementary school students in Mexico: An exploratory study.

Multiple Intelligence (MI) helps to evaluate the brain processes of individuals. Identifying the types of multiple intelligence can help teachers to understand their students better. Several studies have identified MI in school children; nevertheless, in Mexico, these studies have been scarce. Therefore, the objective of this study was to analyze the differences of MI between genders and the grades-in-school of Mexican elementary schoolchildren. In an effort to investigate the differences of MI in elementary school children in Mexico, we provided a self-administered questionnaire to 161 Mexican students. Overall, our findings showed that the students' mean averages in the eight categories of MI were similar in both genders; in fact, the only significant differences in gender were found in intrapersonal intelligence (males reporting higher intrapersonal differences than females). No other significant differences in MI were found, nor were there interaction effects between gender and the grade in school. In summary, these results give us an understanding that the different types of MI may not be that well implemented in elementary school children.

Sleep habits, circadian preferences and substance use in a Mexican population: the use of the Morningness-Eveningness-Stability-Scale improved (MESSi).

This study aimed to validate the Morningness-Eveningness-Stability-Scale improved (MESSi) in Mexico, analyzing the factor structure and sleep habits, combined with the proposal of cutoff values for the scales, and to assess the relationship with substance use. We applied the questionnaires through an online survey to a total sample of 510 Mexicans, aged 18-77 years (M = 27.79, SD = 10.24). The MESSi showed an acceptable fit and the Cronbach's alpha coefficients were good to satisfactory in the Mexican sample in every subscale: Morning Affect (MA, α = 0.90), Eveningness (EV, α = 0.88), Distinctness (DI, α = 0.80). In order to obtain a better interpretation of the MESSi subscales, we decided to propose cutoff points corresponding to the 25th-75th percentile. The categories were depicted as strong trait presence, intermediate trait presence and weak trait presence. When applying the cutoff points for the MESSi sub-scales, with Morning Affect (MA), strong-types went to bed and woke up earlier and had more sleep than weak-types during weekdays and weekends and reported less social jetlag. For Eveningness (EV), strong-types went to bed and woke up later than weak-types on weekdays and weekends. Also, strong-types had a shorter time in bed during weekdays but not on weekends and reported more social jetlag. Lastly, with Distinctness (DI), the results reported that those with a strong-type showed greater amplitude on weekdays and weekends. Furthermore, the MESSi scale found that evening people consumed more alcohol and tobacco. Our study supported the validity and reliability of the MESSi in a Mexican population and the relationship between eveningness and substance consumption. Furthermore, the proposed cutoff scores for the MESSi sub-scales add a novel approach for the measurement and interpretation of the scale.

Morningness-eveningness is not associated with academic performance in the afternoon school shift: Preliminary findings.

BACKGROUND: The effect of morningness-eveningness, sleep habits, and intelligence on academic performance has been studied in a fixed morning school shift. However, no studies have analysed these variables in an afternoon school shift and tested whether morningness-eveningness is related to academic performance beyond sleep habits and intelligence effects. AIMS: The psychometric properties of the Morningness-Eveningness Scale for Children (MESC) were analysed. Additionally, academic performance, sex, intelligence, sleep habits, and morningness-eveningness relationship in a morning and afternoon school shift were compared. SAMPLE: The sample consisted of 400 students at a secondary public school in Reynosa, Tamaulipas, in north-eastern Mexico (195 boys and 205 girls; mean ± SD: 13.85 ± 0.70 years old) attending a double-shift school system: 200 from the morning shift (99 boys and 101 girls) and 200 from the afternoon shift (96 boys and 104 girls). METHODS: The students completed the MESC as a measure of morningness-eveningness, a sleep habits survey, a test of academic performance, and the inductive reasoning subtest (R) of the Primary Mental Abilities battery. RESULTS: Adolescents in the two school shifts did not differ in academic performance and intelligence. In the afternoon shift, adolescents slept longer, reported less sleep deficit and social jet lag, and were more oriented to eveningness than adolescents in the morning shift. Sex (girls), sleep length, inductive reasoning, and morningness were associated with academic performance in the morning shift but only sex and intelligence in the afternoon shift. CONCLUSIONS: The role of morningness-eveningness in academic performance in the afternoon shift is examined.

High and low use of electronic media during nighttime before going to sleep: A comparative study between adolescents attending a morning or afternoon school shift.

This study compared the effects of time spent on electronic media devices during nighttime before going to sleep on the sleep-wake cycle, daytime sleepiness, and chronotype in 568 Mexican students (288 girls, mean age = 14.08) attending a double school shift system (287 from morning shift and 281 from afternoon shift). Students completed anonymous self-report questionnaires. Results suggest that high exposure to an electronic media device may have an impact on their sleep-wake cycle, regardless of their school shift. Adolescents from the afternoon shift reported more time spent on devices. Those from the morning shift reported daytime sleepiness with the use of MP3 player, and from the afternoon shift with the use of computer, MP3 player, and television. Both school shifts reported an intermediate chronotype with all electronic media devices, but the afternoon shift with a tendency towards eveningness with the use of the computer, smartphone, and MP3 player.

Validation of the MESSi among adult workers and young students: General health and personality correlates.

The aim of this study was to provide validity for the Spanish version of the Morningness-Eveningness-Stability Scale - improved (MESSi), a novel evolved assessment of circadian typology which considers the subjective phase and amplitude by morning affect (MA), eveningness (EV) and distinctness (DI; subjective amplitude) sub-scales. Convergence validity of the MESSi with the reduced Morningness-Eveningness Questionnaire (rMEQ) and relationships with the General Health Questionnaire (GHQ-12) and sensitivity to reward and punishment (SR and SP) were analyzed. Two different Spanish samples, young undergraduate students (n = 891, 18-30 years) and adult workers (n = 577, 31-65 years) participated in this study. Exploratory structural equation modeling (ESEM) of MESSi displayed acceptable fit of a three-factors measurement model. Percentiles of the MA, EV and DI sub-scales were obtained for students and adults. The MESSi showed good convergence validity with the rMEQ scores, with a higher correlation coefficient between MA, EV and lower with DI sub-scales. In both, young students and adult workers, MA was negatively related with the GHQ-12 and SP, but the percentage of explained variance (6% and 3%) was lower than the positive correlations between DI, the GHQ-12 and SP (20% and 13%). Morning types presented higher MA and lower EV scores than the other two typologies in both students and adult workers, whereas only differences in DI were found among students (lowest in evening type). Candidates to psychological symptoms and mental disorders ("true cases"), with the clinical cut-off criteria of the GHQ-12, showed lower MA and higher DI in students, whereas only DI was higher for "true cases" among adults. These results supported that subjective amplitude is a factor related to, but also differentiated of, morningness-eveningness (preferred time for a certain activity). The measure of amplitude might be more important than circadian phase in health consequences.