Sleep quality and sleep deprivation: relationship with academic performance in university students during examination period

The beginning of the university brings together maturational, psychosocial and academic changes that make university students more prone to suffer from insufficient or poor quality sleep, which can negatively influence their academic performance. The period of taking exams is a key part of the academic year. However, there are few studies that analyze sleep during this period of time. Our aim is to study the association of sleep quality and sleep deprivation with academic performance during the examination period. A descriptive, cross-sectional and correlational study was carried out with the participation of 640 subjects in the first three years of five faculties belonging to the Universidad Autónoma de Madrid. The instrument used consisted of a questionnaire that included sociodemographic and academic data, Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale and information about the academic performance. During the examination period, a positive association was found between sleep quality and academic performance. University students slept less than desired, both on weekdays and weekends, and the sleep debt during the week was associated with a worse students’ perception of their academic performance. In total, 61.3% of the students believed that their performance would improve by getting more sleep. In addition, low drowsiness and napping were also found. In conclusion, during periods of greater academic demand, an insufficient sleep and poor quality is commonly observed, affecting negatively to their academic performance. Actually, about 2/3 of our subjects believed that their performance would improve by getting more slee

G-band Spectral Synthesis in Solar Magnetic Concentrations

Narrow band imaging in the G-band is commonly used to trace the small magnetic field concentrations of the Sun, although the mechanism that makes them bright has remained unclear. We carry out LTE syntheses of the G-band in an assorted set of semi-empirical model magnetic concentrations. The syntheses include all CH lines as well as the main atomic lines within the band-pass. The model atmospheres produce bright G-band spectra having many properties in common with the observed G-band bright points. In particular, the contrast referred to the quiet Sun is about twice the contrast in continuum wavelengths. The agreement with observations does not depend on the specificities of the model atmosphere, rather it holds from single fluxtubes to MIcro-Structured Magnetic Atmospheres. However, the agreement requires that the real G-band bright points are not spatially resolved, even in the best observations. Since the predicted G-band intensities exceed by far the observed values, we foresee a notable increase of contrast of the G-band images upon improvement of the angular resolution. According to the LTE modeling, the G-band spectrum emerges from the deep photosphere that produces the continuum. Our syntheses also predict solar magnetic concentrations showing up in continuum images but not in the G-band . Finally, we have examined the importance of the CH photo-dissociation in setting the amount of G-band absorption. It turns out to play a minor role.Comment: To appear in ApJ, 554 n2 Jun 20, 33 pages and 9 figure

Las alteraciones metabólicas asociadas a la obesidad están ya presentes en los primeros años de vida: estudio colaborativo español

Los objetivos de este estudio son, realizar una descrip-ción de las características demográficas, antropométricas y de las alteraciones metabólicas de niños atendidos por obe-sidad resaltando las características aquellos casos de obesidad de inicio temprano (< 10 años) y los de inicio precoz (< 5 años), y evaluar la capacidad diagnóstica de la definición de síndrome metabólico (SM) según diferentes criterios. Métodos: Es un estudio retrospectivo, caso-control, trans-versal, multicéntrico. Han participado un total de 10 Uni-dades de Endocrinología Pediátrica de diferentes hospitales españoles con un grupo de 469 niños con obesidad de inicio temprano y otro grupo de 30 niños con obesidad de inicio precoz. El grupo control estuvo constituido por 224 niños sanos menores de 10 años. Se realizó una valoración antro-pométrica y determinación analítica de parámetros del me-tabolismo de los hidratos de carbono y lipidograma. Resultados: La presencia de alteraciones metabólicas asociadas a la obesidad en la etapa infanto-juvenil en Espa-ña es notable, de forma aislada, o englobada bajo la defini-ción de SM. La prevalencia de éste aumenta sustancialmen-te cuando se considera la resistencia periférica a la acción de la insulina como criterio diagnóstico. Se demuestra cómo en niños menores de 10 años, dichas alteraciones están presen-tes en un porcentaje reseñable, y se encuentran las primeras alteraciones metabólicas ya en niños obesos < 5 años. Conclusión: En los niños españoles existen alteracio-nes metabólicas asociadas a la obesidad en la etapa in-fanto-juvenil de forma aislada o englobada bajo la de-finición de SM, y ya están presentes a edades precoces. The objectives of this study are to provide a description of the demographic, anthropometric characteristics and metabolic abnormalities in children with early-onset (< 10 years) and of very-early-onset obesity (< 5 years). We also evaluate the diagnostic ability using the definition of meta-bolic syndrome (MS) according to different criteria. Methods: It is a retrospective, case-control, cross-sec-tional, multicenter study. A total of 10 Pediatric Endo-crinology Units in different Spanish hospitals were in-volved. A group of 469 children with early-onset obesity and another group of 30 children with very early-onset obesity were studied. The control group consisted of 224 healthy children younger than 10 years. Anthropometric and analytical determination of carbohydrates metabo-lism parameters and the lipid profile were performed. Results: The presence of metabolic alterations associa-ted with obesity in children and adolescents in Spain is remarkable, either on their own, or encompassed within the definition of MS. This prevalence increases substan-tially when considering the peripheral resistance to in-sulin action as a diagnostic criterion. It also shows how children who could not be diagnosed with MS according to the definition provided by the International Diabetes Federation (IDF) due to age below 10 years, these altera-tions are already present in a remarkable percentage. In fact, metabolic abnormalities are already present in the very-early-onset obese children (<5 years). Conclusion: In Spanish children there are metabolic alterations associated with obesity in the infant-juvenile stages alone or encompassed within the definition of MS, and are already present at earlier ages

Loss of Gnas Imprinting Differentially Affects REM/NREM Sleep and Cognition in Mice

It has been suggested that imprinted genes are important in the regulation of sleep. However, the fundamental question of whether genomic imprinting has a role in sleep has remained elusive up to now. In this work we show that REM and NREM sleep states are differentially modulated by the maternally expressed imprinted gene Gnas. In particular, in mice with loss of imprinting of Gnas, NREM and complex cognitive processes are enhanced while REM and REM–linked behaviors are inhibited. This is the first demonstration that a specific overexpression of an imprinted gene affects sleep states and related complex behavioral traits. Furthermore, in parallel to the Gnas overexpression, we have observed an overexpression of Ucp1 in interscapular brown adipose tissue (BAT) and a significant increase in thermoregulation that may account for the REM/NREM sleep phenotypes. We conclude that there must be significant evolutionary advantages in the monoallelic expression of Gnas for REM sleep and for the consolidation of REM–dependent memories. Conversely, biallelic expression of Gnas reinforces slow wave activity in NREM sleep, and this results in a reduction of uncertainty in temporal decision-making processes

Insomnia and its correlates in a representative sample of the Greek population

<p>Abstract</p> <p>Background</p> <p>Insomnia is a major public health concern affecting about 10% of the general population in its chronic form. Furthermore, epidemiological surveys demonstrate that poor sleep and sleep dissatisfaction are even more frequent problems (10-48%) in the community. This is the first report on the prevalence of insomnia in Greece, a southeastern European country which differs in several socio-cultural and climatic aspects from the rest of European Community members. Data obtained from a national household survey (n = 1005) were used to assess the relationship between insomnia symptoms and a variety of sociodemographic variables, life habits, and health-related factors.</p> <p>Methods</p> <p>A self-administered questionnaire with questions pertaining to general health and related issues was given to the participants. The Short Form-36 (Mental Health subscale), the Athens Insomnia Scale (AIS) as a measure of insomnia-related symptoms, and the International Physical Activity Questionnaire (IPAQ) were also used for the assessment.</p> <p>Results</p> <p>The prevalence of insomnia in the total sample was 25.3% (n = 254); insomnia was more frequent in women than men (30.7% vs. 19.5%) and increased with age. Multiple regression analysis revealed a significant association of insomnia with low socio-economical status and educational level, physical inactivity, existence of a chronic physical or mental disease and increased number of hospitalizations in the previous year.</p> <p>Conclusions</p> <p>The present study confirms most findings reported from other developed countries around the world regarding the high prevalence of insomnia problems in the general population and their association with several sociodemographic and health-related predisposing factors. These results further indicate the need for more active interventions on the part of physicians who should suspect and specifically ask about such symptoms.</p

Role of NAFLD on the Health Related QoL Response to Lifestyle in Patients With Metabolic Syndrome: The PREDIMED Plus Cohort

ObjectiveTo evaluate the effect of Non-alcoholic fatty liver disease (NAFLD) status in the impact of lifestyle over Health-related quality of life (HRQoL) in patients with metabolic syndrome (MetS). MethodsBaseline and 1 year follow up data from the PREDIMED-plus cohort (men and women, 55-75 years old with overweight/obesity and MetS) were studied. Adherence to an energy-restricted Mediterranean Diet (er-MeDiet) and Physical Activity (PA) were assessed with a validated screeners. Hepatic steatosis index (HSI) was implemented to evaluate NAFLD while the SF-36 questionnaire provided HRQoL evaluation. Statistical analyses were performed to evaluate the influence of baseline NAFLD on HRQoL as affected by lifestyle during 1 year of follow up. ResultsData from 5205 patients with mean age of 65 years and a 48% of female participants. Adjusted linear multivariate mixed regression models showed that patients with lower probability of NAFLD (HSI < 36 points) were more responsive to er-MeDiet (beta 0.64 vs beta 0.05 per er-MeDiet adherence point, p< 0.01) and PA (beta 0.05 vs beta 0.01 per MET-h/week, p = 0.001) than those with high probability for NAFLD in terms Physical SF-36 summary in the 1 year follow up. 10 points of er-MeDiet adherence and 50 MET-h/week were thresholds for a beneficial effect of lifestyle on HRQoL physical domain in patients with lower probability of NAFLD. ConclusionThe evaluation of NAFLD by the HSI index in patients with MetS might identify subjects with different prospective sensitivity to lifestyle changes in terms of physical HRQoL (http://www.isrctn.com/ISRCTN89898870)