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Sample records for delayed sleep phase

  1. Delayed sleep phase cases and controls

    Directory of Open Access Journals (Sweden)

    Nievergelt Caroline M

    2008-04-01

    Full Text Available Abstract Background Delayed sleep phase disorder (DSPD is a condition in which patients have difficulty falling asleep before the early morning hours and commonly have trouble awakening before late morning or even early afternoon. Several studies have suggested that variations in habitual bedtime are 40–50% heritable. Methods We recruited a case series of 205 participants, along with 221 controls (DSPD-C with normal sleep, roughly matched for age, gender, and ancestry. A representative sample of San Diego adults recruited some years before was already available to confirm the control group. Both DSPD and DSPD-C provided blood or saliva samples for DNA and completed extensive questionnaires about sleep habits, sleep history, family history, sleep quality, morningness-eveningness traits, depression, mania, and seasonality of symptoms. The DSPD group wore wrist actigraphs for a median of 13.2 days. The representative sample collected previously had undergone actigraphic recordings, from which 48 hours of data were generally available. Results The DSPD and DSPD-C samples showed almost no overlap on morningness-eveningness scores. DSPD cases went to bed and arose about 3 hours later than the DSPD-C and the representative sample. DSPD cases reported more difficulties with sleep, poorer sleep quality, and more depression, but there was no significant difference in a history of mania. DSPD cases reported more family history of late bedtimes, but female DSPD reported that their fathers' bedtimes were later than the fathers of male DSPD. Conclusion These results indicate a DSPD phenotype is familial and associated with unipolar depression.

  2. Chronic sleep reduction in adolescents with Delayed Sleep Phase Disorder and effects of melatonin treatment

    NARCIS (Netherlands)

    van Maanen, Annette; Dewald-Kaufmann, Julia F.; Smits, Marcel G.; Oort, Frans J.; Meijer, Anne Marie

    2013-01-01

    Homeostatic and circadian changes that occur during adolescence can result in chronic sleep reduction. This may particularly be true for adolescents with Delayed Sleep Phase Disorder (DSPD), which is associated with late Dim Light Melatonin Onset (DLMO). This study assessed the influence of

  3. Academic performance in adolescents with delayed sleep phase.

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    Sivertsen, Børge; Glozier, Nick; Harvey, Allison G; Hysing, Mari

    2015-09-01

    Delayed sleep phase (DSP) in adolescence has been linked to reduced academic performance, but there are few population-based studies examining this association using validated sleep measures and objective outcomes. The youth@hordaland-survey, a large population-based study from Norway conducted in 2012, surveyed 8347 high-school students aged 16-19 years (54% girls). DSP was assessed by self-report sleep measures, and it was operationalized according to the International Classification of Sleep Disorders - Second Edition. School performance (grade point average, GPA) was obtained from official administrative registries, and it was linked individually to health data. DSP was associated with increased odds for poor school performance. After adjusting for age and gender, DSP was associated with a threefold increased odds of poor GPA (lowest quartile) [odds ratio (OR) = 2.95; 95% confidence interval (CI): 2.03-4.30], and adjustment for sociodemographics and lifestyle factors did not, or only slightly, attenuate this association. Adjustment for nonattendance at school reduced the association substantially, and in the fully adjusted model, the effect of DSP on poor academic performance was reduced to a non-significant level. Mediation analyses confirmed both direct and significant indirect effects of DSP on school performance based on school absence, daytime sleepiness, and sleep duration. Poor academic performance may reflect an independent effect of underlying circadian disruption, which in part could be mediated by school attendance, as well as daytime sleepiness and short sleep duration. This suggests that careful assessment of sleep is warranted in addressing educational difficulties. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Sleep and circadian variability in people with delayed sleep-wake phase disorder versus healthy controls.

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    Burgess, Helen J; Park, Margaret; Wyatt, James K; Rizvydeen, Muneer; Fogg, Louis F

    2017-06-01

    To compare sleep and circadian variability in adults with delayed sleep-wake phase disorder (DSWPD) to healthy controls. Forty participants (22 DSWPD, 18 healthy controls) completed a ten-day protocol, consisting of DLMO assessments on two consecutive nights, a five-day study break, followed by two more DLMO assessments. All participants were instructed to sleep within one hour of their self-reported average sleep schedule for the last four days of the study break. We analyzed the participants' wrist actigraphy data during these four days to examine intraindividual variability in sleep timing, duration and efficiency. We also examined shifts in the DLMO from before and after the study break. Under the same conditions, people with DSWPD had significantly more variable wake times and total sleep time than healthy controls (p ≤ 0.015). Intraindividual variability in sleep onset time and sleep efficiency was similar between the two groups (p ≥ 0.30). The DLMO was relatively stable across the study break, with only 11% of controls but 27% of DSWPDs showed more than a one hour shift in the DLMO. Only in the DSWPD sample was greater sleep variability associated with a larger shift in the DLMO (r = 0.46, p = 0.03). These results suggest that intraindividual variability in sleep can be higher in DSWPD versus healthy controls, and this may impact variability in the DLMO. DSWPD patients with higher intraindividual variability in sleep are more likely to have a shifting DLMO, which could impact sleep symptoms and the optimal timing of light and/or melatonin treatment for DSWPD. Circadian Phase Assessments at Home, http://clinicaltrials.gov/show/NCT01487252, NCT01487252. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Objective measures of sleep and dim light melatonin onset in adolescents and young adults with delayed sleep phase disorder compared to healthy controls.

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    Saxvig, Ingvild W; Wilhelmsen-Langeland, Ane; Pallesen, Ståle; Vedaa, Oystein; Nordhus, Inger H; Sørensen, Eli; Bjorvatn, Bjørn

    2013-08-01

    Delayed sleep phase disorder is characterized by a delay in the timing of the major sleep period relative to conventional norms. The sleep period itself has traditionally been described as normal. Nevertheless, it is possible that sleep regulatory mechanism disturbances associated with the disorder may affect sleep duration and/or architecture. Polysomnographic data that may shed light on the issue are scarce. Hence, the aim of this study was to examine polysomnographic measures of sleep in adolescents and young adults with delayed sleep phase disorder, and to compare findings to that of healthy controls. A second aim was to estimate dim light melatonin onset as a marker of circadian rhythm and to investigate the phase angle relationship (time interval) between dim light melatonin onset and the sleep period. Data from 54 adolescents and young adults were analysed, 35 diagnosed with delayed sleep phase disorder and 19 healthy controls. Results show delayed timing of sleep in participants with delayed sleep phase disorder, but once sleep was initiated no group differences in sleep parameters were observed. Dim light melatonin onset was delayed in participants with delayed sleep phase disorder, but no difference in phase angle was observed between the groups. In conclusion, both sleep and dim light melatonin onset were delayed in participants with delayed sleep phase disorder. The sleep period appeared to occur at the same circadian phase in both groups, and once sleep was initiated no differences in sleep parameters were observed. © 2013 European Sleep Research Society.

  6. Delayed sleep phase: An important circadian subtype of sleep disturbance in bipolar disorders.

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    Steinan, Mette Kvisten; Morken, Gunnar; Lagerberg, Trine V; Melle, Ingrid; Andreassen, Ole A; Vaaler, Arne E; Scott, Jan

    2016-02-01

    Theoretical models of Bipolar Disorder (BD) highlight that sleep disturbances may be a marker of underlying circadian dysregulation. However, few studies of sleep in BD have reported on the most prevalent circadian sleep abnormality, namely Delayed Sleep Phase (DSP). A cross-sectional study of 404 adults with BD who met published clinical criteria for insomnia, hypersomnia or DSP, and who had previously participated in a study of sleep in BD using a comprehensive structured interview assessment. About 10% of BD cases with a sleep problem met criteria for a DSP profile. The DSP group was younger and had a higher mean Body Mass Index (BMI) than the other groups. Also, DSP cases were significantly more likely to be prescribed mood stabilizers and antidepressant than insomnia cases. An exploratory analysis of selected symptom item ratings indicated that DSP was significantly more likely to be associated with impaired energy and activity levels. The cross-sectional design precludes examination of longitudinal changes. DSP is identified by sleep profile, not by diagnostic criteria or objective sleep records such as actigraphy. The study uses data from a previous study to identify and examine the DSP group. The DSP group identified in this study can be differentiated from hypersomnia and insomnia groups on the basis of clinical and demographic features. The association of DSP with younger age, higher BMI and impaired energy and activity also suggest that this clinical profile may be a good proxy for underlying circadian dysregulation. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. The Use of Exogenous Melatonin in Delayed Sleep Phase Disorder: a Meta-analysis

    NARCIS (Netherlands)

    Geijlswijk, I.M. van; Korzilius, H.P.L.M.; Smits, M.G.

    2010-01-01

    Study Objectives: To perform a meta-analysis of the efficacy and safety of exogenous melatonin in advancing sleep-wake rhythm in patients with delayed sleep phase disorder. Design: Meta analysis of papers indexed for PubMed, Embase, and the abstracts of sleep and chronobiologic societies

  8. Delayed sleep phase disorder: clinical perspective with a focus on light therapy

    Directory of Open Access Journals (Sweden)

    Figueiro MG

    2016-04-01

    Full Text Available Mariana G Figueiro Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY, USAAbstract: Delayed sleep phase disorder (DSPD is common among adolescents and further increases their susceptibility to chronic sleep restriction and associated detrimental outcomes, including increased risk of depression, drug and alcohol use, behavioral problems, and poor scholastic performance. DSPD is characterized by sleep onset that occurs significantly later than desired bedtimes and societal norms. Individuals with DSPD exhibit long sleep latencies when attempting to sleep at conventional bedtimes. Circadian sleep disorders such as DSPD can occur when there is misalignment between sleep timing and societal norms. This review discusses studies using light therapy to advance the timing of sleep in adolescents and college students, in particular on those suffering from DSPD. A discussion on how to increase effectiveness of light therapy in the field will also be provided.Keywords: circadian, melatonin, light, sleep, sleep phase disorder, adolescents

  9. Prevalence and correlates of delayed sleep phase in high school students.

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    Saxvig, Ingvild W; Pallesen, Ståle; Wilhelmsen-Langeland, Ane; Molde, Helge; Bjorvatn, Bjørn

    2012-02-01

    To investigate prevalence and correlates of delayed sleep phase, characterized by problems falling asleep in the evening and rising at adequate times in the morning, in a large sample of Norwegian high school students. A randomized sample of 1285 high school students (aged 16-19 years) participated in an internet based study answering questions about sleep habits, height, weight, smoking, alcohol use, school grades, and anxiety and depression symptoms. Delayed sleep phase was operationalized as difficulties falling asleep before 2 a.m. at least three nights per week together with much or very much difficulty waking up in the morning. The results show a prevalence of delayed sleep phase of 8.4%. In all, 68% of these students (5.7% of the total sample) also reported problems advancing their sleep period as well as one daytime consequence (oversleeping at least two days a week or experiencing much/very much sleepiness at school). Delayed sleep phase was associated with lower average school grades, smoking, alcohol usage, and elevated anxiety and depression scores. Delayed sleep phase appears to be common amongst Norwegian adolescents and is associated with negative outcomes such as lower average school grades, smoking, alcohol usage, and elevated anxiety and depression scores. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Delayed sleep phase disorder: clinical perspective with a focus on light therapy

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    Figueiro, Mariana G

    2016-01-01

    Mariana G Figueiro Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY, USAAbstract: Delayed sleep phase disorder (DSPD) is common among adolescents and further increases their susceptibility to chronic sleep restriction and associated detrimental outcomes, including increased risk of depression, drug and alcohol use, behavioral problems, and poor scholastic performance. DSPD is characterized by sleep onset that occurs significantly later than desired bedtimes and societal no...

  11. Circadian phase, dynamics of subjective sleepiness and sensitivity to blue light in young adults complaining of a delayed sleep schedule.

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    Moderie, Christophe; Van der Maren, Solenne; Dumont, Marie

    2017-06-01

    To assess factors that might contribute to a delayed sleep schedule in young adults with sub-clinical features of delayed sleep phase disorder. Two groups of 14 young adults (eight women) were compared: one group complaining of a delayed sleep schedule and a control group with an earlier bedtime and no complaint. For one week, each subject maintained a target bedtime reflecting their habitual sleep schedule. Subjects were then admitted to the laboratory for the assessment of circadian phase (dim light melatonin onset), subjective sleepiness, and non-visual light sensitivity. All measures were timed relative to each participant's target bedtime. Non-visual light sensitivity was evaluated using subjective sleepiness and salivary melatonin during 1.5-h exposure to blue light, starting one hour after target bedtime. Compared to control subjects, delayed subjects had a later circadian phase and a slower increase of subjective sleepiness in the late evening. There was no group difference in non-visual sensitivity to blue light, but we found a positive correlation between melatonin suppression and circadian phase within the delayed group. Our results suggest that a late circadian phase, a slow build-up of sleep need, and an increased circadian sensitivity to blue light contribute to the complaint of a delayed sleep schedule. These findings provide targets for strategies aiming to decreasing the severity of a sleep delay and the negative consequences on daytime functioning and health. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Are cognitive "insomnia" processes involved in the development and maintenance of delayed sleep wake phase disorder?

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    Richardson, Cele E; Gradisar, Michael; Barbero, Sebastian C

    2016-04-01

    Although individuals with delayed sleep wake phase disorder (DSWPD) and chronic insomnia disorder (CID) share many of the same phenomenological experiences, theories relating to the development and maintenance of these disorders are distinct in focus. Unlike CID, theory relating to DSWPD is primarily physiologically based and assumes almost no cognitive pathway. However, recent research findings suggest that individuals with DSWPD also display many of the sleep-disordered cognitive processes that were previously assumed to be unique to the insomnia experience. As such, this review aims to summarise current research findings to address the question "Could cognitive processes be involved in the development and maintenance of DSWPD?" In particular, the presence of cognitive and physiological pre-sleep arousal, sleep-related attentional bias, distorted perception of sleep and daytime functioning, dysfunctional beliefs and safety behaviours will be investigated. As this emerging area of research requires a stronger evidence base, we highlight suggestions for future investigation and provide preliminary practice points for clinicians assessing and treating "insomnia" in patients with DSWPD. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Sleep Phase Delay in Cystic Fibrosis: A Potential New Manifestation of Cystic Fibrosis Transmembrane Regulator Dysfunction.

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    Jensen, Judy L; Jones, Christopher R; Kartsonaki, Christiana; Packer, Kristyn A; Adler, Frederick R; Liou, Theodore G

    2017-08-01

    Cystic fibrosis (CF) transmembrane regulator (CFTR) protein dysfunction causes CF. Improving survival allows detection of increasingly subtle disease manifestations. CFTR dysfunction in the central nervous system (CNS) may disturb circadian rhythm and thus sleep phase. We studied sleep in adults to better understand potential CNS CFTR dysfunction. We recruited participants from April 2012 through April 2015 and administered the Munich Chronotype Questionnaire (MCTQ). We compared free-day sleep measurements between CF and non-CF participants and investigated associations with CF survival predictors. We recruited 23 female and 22 male adults with CF aged 18 to 46 years and 26 female and 22 male volunteers aged 18 to 45 years. Compared with volunteers without CF, patients with CF had delayed sleep onset (0.612 h; P = .015), midsleep (1.11 h; P < .001), and wake (1.15 h; P < .001) times and prolonged sleep latency (7.21 min; P = .05) and duration (0.489 h; P = .05). Every hour delay in sleep onset was associated with shorter sleep duration by 0.29 h in patients with CF and 0.75 h in subjects without CF (P = .007) and longer sleep latency by 7.51 min in patients with CF and 1.6 min in volunteers without CF (P = .035). Among patients with CF, FEV 1 % predicted, prior acute pulmonary exacerbations, and weight were independent of all free-day sleep measurements. CF in adults is associated with marked delays in sleep phase consistent with circadian rhythm phase delays. Independence from disease characteristics predictive of survival suggests that sleep phase delay is a primary manifestation of CFTR dysfunction in the CNS. Copyright © 2017 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

  14. Home dim light melatonin onsets with measures of compliance in delayed sleep phase disorder.

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    Burgess, Helen J; Park, Margaret; Wyatt, James K; Fogg, Louis F

    2016-06-01

    The dim light melatonin onset (DLMO) assists with the diagnosis and treatment of circadian rhythm sleep disorders. Home DLMOs are attractive for cost savings and convenience, but can be confounded by home lighting and sample timing errors. We developed a home saliva collection kit with objective measures of light exposure and sample timing. We report on our first test of the kit in a clinical population. Thirty-two participants with delayed sleep phase disorder (DSPD; 17 women, aged 18-52 years) participated in two back-to-back home and laboratory phase assessments. Most participants (66%) received at least one 30-s epoch of light >50 lux during the home phase assessments, but for only 1.5% of the time. Most participants (56%) collected every saliva sample within 5 min of the scheduled time. Eighty-three per cent of home DLMOs were not affected by light or sampling errors. The home DLMOs occurred, on average, 10.2 min before the laboratory DLMOs, and were correlated highly with the laboratory DLMOs (r = 0.93, P light exposure and sample timing, can assist in identifying accurate home DLMOs. © 2016 European Sleep Research Society.

  15. Phase delaying the human circadian clock with a single light pulse and moderate delay of the sleep/dark episode: no influence of iris color.

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    Canton, Jillian L; Smith, Mark R; Choi, Ho-Sun; Eastman, Charmane I

    2009-07-17

    Light exposure in the late evening and nighttime and a delay of the sleep/dark episode can phase delay the circadian clock. This study assessed the size of the phase delay produced by a single light pulse combined with a moderate delay of the sleep/dark episode for one day. Because iris color or race has been reported to influence light-induced melatonin suppression, and we have recently reported racial differences in free-running circadian period and circadian phase shifting in response to light pulses, we also tested for differences in the magnitude of the phase delay in subjects with blue and brown irises. Subjects (blue-eyed n = 7; brown eyed n = 6) maintained a regular sleep schedule for 1 week before coming to the laboratory for a baseline phase assessment, during which saliva was collected every 30 minutes to determine the time of the dim light melatonin onset (DLMO). Immediately following the baseline phase assessment, which ended 2 hours after baseline bedtime, subjects received a 2-hour bright light pulse (~4,000 lux). An 8-hour sleep episode followed the light pulse (i.e. was delayed 4 hours from baseline). A final phase assessment was conducted the subsequent night to determine the phase shift of the DLMO from the baseline to final phase assessment.Phase delays of the DLMO were compared in subjects with blue and brown irises. Iris color was also quantified from photographs using the three dimensions of red-green-blue color axes, as well as a lightness scale. These variables were correlated with phase shift of the DLMO, with the hypothesis that subjects with lighter irises would have larger phase delays. The average phase delay of the DLMO was -1.3 +/- 0.6 h, with a maximum delay of ~2 hours, and was similar for subjects with blue and brown irises. There were no significant correlations between any of the iris color variables and the magnitude of the phase delay. A single 2-hour bright light pulse combined with a moderate delay of the sleep/dark episode

  16. Phase delaying the human circadian clock with a single light pulse and moderate delay of the sleep/dark episode: no influence of iris color

    Directory of Open Access Journals (Sweden)

    Choi Ho-Sun

    2009-07-01

    Full Text Available Abstract Background Light exposure in the late evening and nighttime and a delay of the sleep/dark episode can phase delay the circadian clock. This study assessed the size of the phase delay produced by a single light pulse combined with a moderate delay of the sleep/dark episode for one day. Because iris color or race has been reported to influence light-induced melatonin suppression, and we have recently reported racial differences in free-running circadian period and circadian phase shifting in response to light pulses, we also tested for differences in the magnitude of the phase delay in subjects with blue and brown irises. Methods Subjects (blue-eyed n = 7; brown eyed n = 6 maintained a regular sleep schedule for 1 week before coming to the laboratory for a baseline phase assessment, during which saliva was collected every 30 minutes to determine the time of the dim light melatonin onset (DLMO. Immediately following the baseline phase assessment, which ended 2 hours after baseline bedtime, subjects received a 2-hour bright light pulse (~4,000 lux. An 8-hour sleep episode followed the light pulse (i.e. was delayed 4 hours from baseline. A final phase assessment was conducted the subsequent night to determine the phase shift of the DLMO from the baseline to final phase assessment. Phase delays of the DLMO were compared in subjects with blue and brown irises. Iris color was also quantified from photographs using the three dimensions of red-green-blue color axes, as well as a lightness scale. These variables were correlated with phase shift of the DLMO, with the hypothesis that subjects with lighter irises would have larger phase delays. Results The average phase delay of the DLMO was -1.3 ± 0.6 h, with a maximum delay of ~2 hours, and was similar for subjects with blue and brown irises. There were no significant correlations between any of the iris color variables and the magnitude of the phase delay. Conclusion A single 2-hour bright light

  17. Delayed Sleep and Sleep Loss in University Students.

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    Lack, Leon C.

    1986-01-01

    A sample of 211 first-year psychology students completed a questionnaire of sleep habits and difficulities. It was discovered that Delayed Sleep Phase Syndrome may be a significant problem in university student populations. (Author/JD)

  18. A Randomized Controlled Trial of Cognitive-Behavior Therapy Plus Bright Light Therapy for Adolescent Delayed Sleep Phase Disorder

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    Gradisar, Michael; Dohnt, Hayley; Gardner, Greg; Paine, Sarah; Starkey, Karina; Menne, Annemarie; Slater, Amy; Wright, Helen; Hudson, Jennifer L.; Weaver, Edward; Trenowden, Sophie

    2011-01-01

    Objective: To evaluate cognitive-behavior therapy plus bright light therapy (CBT plus BLT) for adolescents diagnosed with delayed sleep phase disorder (DSPD). Design: Randomized controlled trial of CBT plus BLT vs. waitlist (WL) control with comparisons at pre- and post-treatment. There was 6-month follow-up for the CBT plus BLT group only. Setting: Flinders University Child & Adolescent Sleep Clinic, Adelaide, South Australia. Patients: 49 adolescents (mean age 14.6 ± 1.0 y, 53% males) diagnosed with DSPD; mean chronicity 4 y 8 months; 16% not attending school. Eighteen percent of adolescents dropped out of the study (CBT plus BLT: N = 23 vs WL: N = 17). Interventions: CBT plus BLT consisted of 6 individual sessions, including morning bright light therapy to advance adolescents' circadian rhythms, and cognitive restructuring and sleep education to target associated insomnia and sleep hygiene. Measurements and Results: DSPD diagnosis was performed via a clinical interview and 7-day sleep diary. Measurements at each time-point included online sleep diaries and scales measuring sleepiness, fatigue, and depression symptoms. Compared to WL, moderate-to-large improvements (d = 0.65-1.24) were found at post-treatment for CBT plus BLT adolescents, including reduced sleep latency, earlier sleep onset and rise times, total sleep time (school nights), wake after sleep onset, sleepiness, and fatigue. At 6-month follow-up (N = 15), small-to-large improvements (d = 0.24-1.53) continued for CBT plus BLT adolescents, with effects found for all measures. Significantly fewer adolescents receiving CBT plus BLT met DPSD criteria at post-treatment (WL = 82% vs. CBT plus BLT = 13%, P sleep and daytime impairments in the immediate and long-term. Studies evaluating the treatment effectiveness of each treatment component are needed. Clinical Trial Information: Australia – New Zealand Trials Registry Number: ACTRN12610001041044. Citation: Gradisar M; Dohnt H; Gardner G; Paine S; Starkey

  19. The prevalence of probable delayed-sleep-phase syndrome in students from junior high school to university in Tottori, Japan.

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    Hazama, Gen-i; Inoue, Yuichi; Kojima, Kazushige; Ueta, Toshiyuki; Nakagome, Kazuyuki

    2008-09-01

    Delayed sleep phase syndrome (DSPS) is a circadian rhythm sleep disorder with a typical onset in the second decade of life. DSPS is characterized by the sleep-onset insomnia and the difficulty in waking at the desired time in the morning. Although DSPS is associated with inability to attend school, the prevalence has been controversial. To elucidate a change in the prevalence of DSPS among young population, epidemiological survey was conducted on Japanese students. A total of 4,971 students of junior high school, senior high school, and university were enrolled in this cross sectional study in Tottori Prefecture. They answered anonymous screening questionnaire regarding school schedule, sleep hygiene and symptomatic items of sleep disorders. The prevalence of probable DSPS was estimated at 0.48% among the total subject students without gender difference. In university, the prevalence of the last year students showed the highest value (1.66%), while that of the first year students showed the lowest value (0.09%) among all school years from junior high school to university. The prevalence increased with advancing university school years. Thus, a considerable number of Japanese students are affected with DSPS. Senior students of university are more vulnerable to the disorder than younger students. Appropriate school schedule may decrease the mismatch between the individual's sleep-wake cycle and the school schedule. Promotion of a regular sleep habit is necessary to prevent DSPS among this population.

  20. Attention bias for sleep-related stimuli in primary insomnia and delayed sleep phase syndrome using the dot-probe task.

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    MacMahon, Kenneth M A; Broomfield, Niall M; Espie, Colin A

    2006-11-01

    Cognitive models of primary insomnia (PI) suggest attention bias as a maintaining process. This study used a hallmark measure of attention bias, the dot-probe task, to determine whether attention bias to sleep-related stimuli is present in individuals with PI. Control groups of good sleepers (GS) and individuals with delayed sleep phase syndrome (DSPS), a sleep disorder with no presumed cognitive pathway and, hence, no predicted association with attention bias, were included. A between-groups (PI, DSPS, GS) design was employed. Participants completed a dot-probe task with stimuli comprising sleep-related and neutral words, balanced for length and frequency of usage. It was predicted a priori that PI would show greater attention bias to sleep stimuli compared with GS and DSPS groups. No difference between GS and DSPS was predicted. Sixty-three individuals completed the study (PI = 21; DSPS = 22; GS = 20), with those in PI and DSPS classified by International Classification of Sleep Disorders criteria according to self-report sleep diaries and actigraphy. GS scored Sleep Quality Index, reported being good sleepers, and met no criteria for a current or previous sleep disorder. N/A. As predicted, PI showed increased vigilance for sleep-related stimuli relative to GS and DSPS. No differences between GS and those with DSPS were found. The PI group showed shorter response latencies relative to the GS and DSPS groups. Results support an association between attention bias and PI. Further work must determine whether or not attention bias is a causal factor. Speeded responses in the PI group suggest heightened arousal, indicating that physiologic factors may play a related role.

  1. Polymorphism in the PER3 promoter associates with diurnal preference and delayed sleep phase disorder.

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    Archer, Simon N; Carpen, Jayshan D; Gibson, Mark; Lim, Gim Hui; Johnston, Jonathan D; Skene, Debra J; von Schantz, Malcolm

    2010-05-01

    To screen the PER3 promoter for polymorphisms and investigate the phenotypic associations of these polymorphisms with diurnal preference, delayed sleep phase disorder/syndrome (DSPD/DSPS), and their effects on reporter gene expression. Interspecific comparison was used to define the approximate extent of the PER3 promoter as the region between the transcriptional start site and nucleotide position -874. This region was screened in DNA pools using PCR and direct sequencing, which was also used to screen DNA from individual participants. The different promoter alleles were cloned into a luciferase expression vector and a deletion library created. Promoter activation was measured by chemiluminescence. N/A. DNA samples were obtained from volunteers with defined diurnal preference (3 x 80, selected from a pool of 1,590), and DSPD patients (n=23). N/A. We verified three single nucleotide polymorphisms (G -320T, C -319A, G -294A), and found a novel variable number tandem repeat (VNTR) polymorphism (-318 1/2 VNTR). The -320T and -319A alleles occurred more frequently in DSPD compared to morning (P = 0.042 for each) or evening types (P = 0.006 and 0.033). The allele combination TA2G was more prevalent in DSPD compared to morning (P 0.033) or evening types (P = 0.002). Luciferase expression driven by the TA2G combination was greater than for the more common GC2A (P < 0.05) and the rarer TA1G (P < 0.001) combinations. Deletion reporter constructs identified two enhancer regions (-703 to -605, and -283 to -80). Polymorphisms in the PER3 promoter could affect its expression, leading to potential differences in the observed functions of PER3.

  2. Clinical Practice Guideline for the Treatment of Intrinsic Circadian Rhythm Sleep-Wake Disorders: Advanced Sleep-Wake Phase Disorder (ASWPD), Delayed Sleep-Wake Phase Disorder (DSWPD), Non-24-Hour Sleep-Wake Rhythm Disorder (N24SWD), and Irregular Sleep-Wake Rhythm Disorder (ISWRD). An Update for 2015

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    Auger, R. Robert; Burgess, Helen J.; Emens, Jonathan S.; Deriy, Ludmila V.; Thomas, Sherene M.; Sharkey, Katherine M.

    2015-01-01

    A systematic literature review and meta-analyses (where appropriate) were performed and the GRADE approach was used to update the previous American Academy of Sleep Medicine Practice Parameters on the treatment of intrinsic circadian rhythm sleep-wake disorders. Available data allowed for positive endorsement (at a second-tier degree of confidence) of strategically timed melatonin (for the treatment of DSWPD, blind adults with N24SWD, and children/ adolescents with ISWRD and comorbid neurological disorders), and light therapy with or without accompanying behavioral interventions (adults with ASWPD, children/adolescents with DSWPD, and elderly with dementia). Recommendations against the use of melatonin and discrete sleep-promoting medications are provided for demented elderly patients, at a second- and first-tier degree of confidence, respectively. No recommendations were provided for remaining treatments/ populations, due to either insufficient or absent data. Areas where further research is needed are discussed. Citation: Auger RR, Burgess HJ, Emens JS, Deriy LV, Thomas SM, Sharkey KM. Clinical practice guideline for the treatment of intrinsic circadian rhythm sleep-wake disorders: advanced sleep-wake phase disorder (ASWPD), delayed sleep-wake phase disorder (DSWPD), non-24-hour sleep-wake rhythm disorder (N24SWD), and irregular sleep-wake rhythm disorder (ISWRD). An update for 2015. J Clin Sleep Med 2015;11(10):1199–1236. PMID:26414986

  3. A randomised controlled trial of bright light therapy and morning activity for adolescents and young adults with Delayed Sleep-Wake Phase Disorder.

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    Richardson, C; Cain, N; Bartel, K; Micic, G; Maddock, B; Gradisar, M

    2018-05-01

    A randomised controlled trial evaluated bright light therapy and morning activity for the treatment of Delayed Sleep-Wake Phase Disorder (DSWPD) in young people. 60 adolescents and young adults (range = 13-24 years, mean = 15.9 ± 2.2 y, 63% f) diagnosed with DSWPD were randomised to receive three weeks of post-awakening Green Bright Light Therapy (∼507 nm) and Sedentary Activity (sitting, watching TV), Green Bright Light Therapy and Morning Activity (standing, playing motion-sensing videogame), Red Light Therapy (∼643 nm) and Sedentary Activity or Red Light Therapy and Morning Activity. Sleep (ie sleep onset time, wake up time, sleep onset latency, total sleep time) and daytime functioning (ie morning alertness, daytime sleepiness, fatigue, functional impairment) were measured pre-treatment, post-treatment and at one and three month follow-up. Contrary to predictions, there were no significant differences in outcomes between treatment groups; and interaction effects between treatment group and time for all outcome variables were not statistically significant. However, adolescents and young adults in morning activity conditions did not meaningfully increase their objective activity (ie movement frequency). Overall, adolescents reported significantly improved sleep timing (d = 0.30-0.46), sleep onset latency (d = 0.32) and daytime functioning (d = 0.45-0.87) post-treatment. Improvements in sleep timing (d = 0.53-0.61), sleep onset latency (d = 0.57), total sleep time (d = 0.51), and daytime functioning (d = 0.52-1.02) were maintained, or improved upon, at the three month follow-up. However, relapse of symptomology was common and 38% of adolescents and young adults requested further treatment in addition to the three weeks of light therapy. Although there is convincing evidence for the short-term efficacy of chronobiological treatments for DSWPD, long-term treatment outcomes can be improved. To address this gap in our current knowledge

  4. Time delay between cardiac and brain activity during sleep transitions

    NARCIS (Netherlands)

    Long, X.; Arends, J.B.A.M.; Aarts, R.M.; Haakma, R.; Fonseca, P.; Rolink, J.

    2015-01-01

    Human sleep consists of wake, rapid-eye-movement (REM) sleep, and non-REM (NREM) sleep that includes light and deep sleep stages. This work investigated the time delay between changes of cardiac and brain activity for sleep transitions. Here, the brain activity was quantified by

  5. Time delay between cardiac and brain activity during sleep transitions

    Science.gov (United States)

    Long, Xi; Arends, Johan B.; Aarts, Ronald M.; Haakma, Reinder; Fonseca, Pedro; Rolink, Jérôme

    2015-04-01

    Human sleep consists of wake, rapid-eye-movement (REM) sleep, and non-REM (NREM) sleep that includes light and deep sleep stages. This work investigated the time delay between changes of cardiac and brain activity for sleep transitions. Here, the brain activity was quantified by electroencephalographic (EEG) mean frequency and the cardiac parameters included heart rate, standard deviation of heartbeat intervals, and their low- and high-frequency spectral powers. Using a cross-correlation analysis, we found that the cardiac variations during wake-sleep and NREM sleep transitions preceded the EEG changes by 1-3 min but this was not the case for REM sleep transitions. These important findings can be further used to predict the onset and ending of some sleep stages in an early manner.

  6. Delayed sleep timing and symptoms in adults with attention-deficit/hyperactivity disorder: a controlled actigraphy study.

    Science.gov (United States)

    Gamble, Karen L; May, Roberta S; Besing, Rachel C; Tankersly, Amelia P; Fargason, Rachel E

    2013-05-01

    Patients with attention-deficit/hyperactivity disorder (ADHD) often exhibit disrupted sleep and circadian rhythms. Determination of whether sleep disturbance and/or circadian disruption are differentially associated with symptom severity is necessary to guide development of future treatment strategies. Therefore, we measured sleep and ADHD symptoms in participants aged 19-65 who met the DSM-IV-TR (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision) criteria for ADHD and insomnia without psychiatric comorbidities by monitoring actigraphy and daily sleep logs for 2 wks, as well as the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), the ADHD Rating Scale (ADHD-RS), and a clinic-designed sleep behavior questionnaire. Principal components analysis identified correlated circadian- and sleep-related variables in all participants with ADHD who completed the study (n = 24). The identified components were entered into a backwards stepwise linear regression analysis, which indicated that delayed sleep timing and increased sleepiness (ESS) (but not sleep duration or sleep efficiency) significantly predicted greater severity of both hyperactive-impulsive and inattentive ADHD symptoms (p sleep quality (PSQI scores; p sleep" compared with 57.2% and 50% of inattentive and symptom-controlled participants, respectively (p sleep timing and daytime sleepiness, suggesting that treatment interventions aimed at advancing circadian phase may improve daytime sleepiness. In addition, ADHD adults with combined hyperactive-impulsive and inattentive symptoms have decreased sleep quality as well as the delayed sleep timing of predominately inattentive subtypes.

  7. A longitudinal assessment of sleep timing, circadian phase, and phase angle of entrainment across human adolescence.

    Directory of Open Access Journals (Sweden)

    Stephanie J Crowley

    Full Text Available The aim of this descriptive analysis was to examine sleep timing, circadian phase, and phase angle of entrainment across adolescence in a longitudinal study design. Ninety-four adolescents participated; 38 (21 boys were 9-10 years ("younger cohort" and 56 (30 boys were 15-16 years ("older cohort" at the baseline assessment. Participants completed a baseline and then follow-up assessments approximately every six months for 2.5 years. At each assessment, participants wore a wrist actigraph for at least one week at home to measure self-selected sleep timing before salivary dim light melatonin onset (DLMO phase - a marker of the circadian timing system - was measured in the laboratory. Weekday and weekend sleep onset and offset and weekend-weekday differences were derived from actigraphy. Phase angles were the time durations from DLMO to weekday sleep onset and offset times. Each cohort showed later sleep onset (weekend and weekday, later weekend sleep offset, and later DLMO with age. Weekday sleep offset shifted earlier with age in the younger cohort and later in the older cohort after age 17. Weekend-weekday sleep offset differences increased with age in the younger cohort and decreased in the older cohort after age 17. DLMO to sleep offset phase angle narrowed with age in the younger cohort and became broader in the older cohort. The older cohort had a wider sleep onset phase angle compared to the younger cohort; however, an age-related phase angle increase was seen in the younger cohort only. Individual differences were seen in these developmental trajectories. This descriptive study indicated that circadian phase and self-selected sleep delayed across adolescence, though school-day sleep offset advanced until no longer in high school, whereupon offset was later. Phase angle changes are described as an interaction of developmental changes in sleep regulation interacting with psychosocial factors (e.g., bedtime autonomy.

  8. Irregular sleep/wake patterns are associated with poorer academic performance and delayed circadian and sleep/wake timing.

    Science.gov (United States)

    Phillips, Andrew J K; Clerx, William M; O'Brien, Conor S; Sano, Akane; Barger, Laura K; Picard, Rosalind W; Lockley, Steven W; Klerman, Elizabeth B; Czeisler, Charles A

    2017-06-12

    The association of irregular sleep schedules with circadian timing and academic performance has not been systematically examined. We studied 61 undergraduates for 30 days using sleep diaries, and quantified sleep regularity using a novel metric, the sleep regularity index (SRI). In the most and least regular quintiles, circadian phase and light exposure were assessed using salivary dim-light melatonin onset (DLMO) and wrist-worn photometry, respectively. DLMO occurred later (00:08 ± 1:54 vs. 21:32 ± 1:48; p sleep propensity rhythm peaked later (06:33 ± 0:19 vs. 04:45 ± 0:11; p academic performance and SRI was observed. These findings show that irregular sleep and light exposure patterns in college students are associated with delayed circadian rhythms and lower academic performance. Moreover, the modeling results reveal that light-based interventions may be therapeutically effective in improving sleep regularity in this population.

  9. Significant Sleep Dysregulation in a Toddler With Developmental Delay.

    Science.gov (United States)

    Stein, Martin T; Owens, Judith; Abbott, Myles

    Derrick's parents made an appointment with a new pediatrician for a second opinion about disordered sleep. Now 22-months old, he was evaluated at 18 months of age for developmental delay when he was found to have "a regulatory disorder associated with delays in language and motor development, hypotonia and significant sleep problems." The parents are now most concerned about his sleeping pattern. Prolonged sleep onset and frequent night awaking occur each night since 6-months of age. These problems are more severe in the past few months when he awakes screaming and cannot be settled. The awakening episodes occur 2 to 4 times each night when "he screams and thrashes his body for up to an hour." Daytime tantrums increased. After the parents read a book about sleep in young children, they provided a calm atmosphere at bedtime including a dark room and singing a quiet lullaby. When these changes did not alter sleep, they purchased a vibrating mattress which was also unsuccessful.Derrick was born full term after an uncomplicated prenatal and perinatal course. He sat at 10 months, crawled at 12 months, and walked at 18 months. He currently drinks from a sippy cup and he can use a utensil to eat. He has few words saying only "no" and "mama" in the past month. Imitation of some words occurred recently. He has responded to simple directions in the past 2 months. Derrick passed the newborn audiology screen. He does not have difficulty swallowing and he does not drool. He plays with many different toys and he plays in parallel with his older brother who also experienced delays in motor and language development. His brother is now doing very well in school. There is no family history of cognitive delay, seizure disorder, cerebral palsy, early developmental delay (other than the brother) or a significant sleep problem. PHYSICAL EXAMINATION:: head circumference, length and weight (75th percentile). He had mild generalized hypotonia, mild weakness, 2+ symmetrical deep tendon

  10. Sleep Problems and Early Developmental Delay: Implications for Early Intervention Programs

    Science.gov (United States)

    Bonuck, Karen; Grant, Roy

    2012-01-01

    Sleep disorders negatively impact behavior, cognition, and growth--the same areas targeted by early intervention. Conversely, developmental delays and disabilities may themselves precipitate sleep disorders. Young children with developmental delays experience sleep disorders at a higher rate than do typically developing children; the most common…

  11. Association between lunar phase and sleep characteristics.

    Science.gov (United States)

    Turányi, Csilla Zita; Rónai, Katalin Zsuzsanna; Zoller, Rezső; Véber, Orsolya; Czira, Mária Eszter; Újszászi, Ákos; László, Gergely; Szentkirályi, András; Dunai, Andrea; Lindner, Anett; Szőcs, Julianna Luca; Becze, Ádám; Kelemen, Andrea; Lendvai, Zsófia; Molnar, Miklos Z; Mucsi, István; Novák, Márta

    2014-11-01

    Popular belief holds that the lunar cycle affects human physiology, behavior, and health, including sleep. To date, only a few and conflicting analyses have been published about the association between lunar phases and sleep. Our aim was to analyze the relationship between lunar phases and sleep characteristics. In this retrospective, cross-sectional analysis, data from 319 patients who had been referred for sleep study were included. Individuals with apnea-hypopnea index ≥ 15/h were excluded. Socio-demographic parameters were recorded. All participants underwent one-night standard polysomnography. Associations between lunar cycle (new moon, full moon and alternate moon) and sleep parameters were examined in unadjusted and adjusted models. Fifty-seven percent of patients were males. Mean age for men was 45 ± 14 years and 51 ± 12 years for women. In total, 224 persons had their sleep study done during alternate moon, 47 during full moon, and 48 during new moon. Full moon was associated with lower sleep efficiency [median (%) (IQR): new moon 82 (18), full moon 74 (19), alternate moon 82 (15); P < 0.001], less deep sleep [median (%) (IQR): new moon 9 (9), full moon 6 (4), alternate moon 11 (9); P < 0.001], and increased REM latency [median (min) (IQR): new moon 98 (74), full moon 137 (152), alternate moon 97 (76); P < 0.001], even after adjustment for several covariables. The results are consistent with a recent report and the widely held belief that sleep characteristics may be associated with the full moon. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Atmospheric Phase Delay in Sentinel SAR Interferometry

    Science.gov (United States)

    Krishnakumar, V.; Monserrat, O.; Crosetto, M.; Crippa, B.

    2018-04-01

    The repeat-pass Synthetic Aperture Radio Detection and Ranging (RADAR) Interferometry (InSAR) has been a widely used geodetic technique for observing the Earth's surface, especially for mapping the Earth's topography and deformations. However, InSAR measurements are prone to atmospheric errors. RADAR waves traverse the Earth's atmosphere twice and experience a delay due to atmospheric refraction. The two major layers of the atmosphere (troposphere and ionosphere) are mainly responsible for this delay in the propagating RADAR wave. Previous studies have shown that water vapour and clouds present in the troposphere and the Total Electron Content (TEC) of the ionosphere are responsible for the additional path delay in the RADAR wave. The tropospheric refractivity is mainly dependent on pressure, temperature and partial pressure of water vapour. The tropospheric refractivity leads to an increase in the observed range. These induced propagation delays affect the quality of phase measurement and introduce errors in the topography and deformation fields. The effect of this delay was studied on a differential interferogram (DInSAR). To calculate the amount of tropospheric delay occurred, the meteorological data collected from the Spanish Agencia Estatal de Meteorología (AEMET) and MODIS were used. The interferograms generated from Sentinel-1 carrying C-band Synthetic Aperture RADAR Single Look Complex (SLC) images acquired on the study area are used. The study area consists of different types of scatterers exhibiting different coherence. The existing Saastamoinen model was used to perform a quantitative evaluation of the phase changes caused by pressure, temperature and humidity of the troposphere during the study. Unless the phase values due to atmospheric disturbances are not corrected, it is difficult to obtain accurate measurements. Thus, the atmospheric error correction is essential for all practical applications of DInSAR to avoid inaccurate height and deformation

  13. ATMOSPHERIC PHASE DELAY IN SENTINEL SAR INTERFEROMETRY

    Directory of Open Access Journals (Sweden)

    V. Krishnakumar

    2018-04-01

    Full Text Available The repeat-pass Synthetic Aperture Radio Detection and Ranging (RADAR Interferometry (InSAR has been a widely used geodetic technique for observing the Earth’s surface, especially for mapping the Earth’s topography and deformations. However, InSAR measurements are prone to atmospheric errors. RADAR waves traverse the Earth’s atmosphere twice and experience a delay due to atmospheric refraction. The two major layers of the atmosphere (troposphere and ionosphere are mainly responsible for this delay in the propagating RADAR wave. Previous studies have shown that water vapour and clouds present in the troposphere and the Total Electron Content (TEC of the ionosphere are responsible for the additional path delay in the RADAR wave. The tropospheric refractivity is mainly dependent on pressure, temperature and partial pressure of water vapour. The tropospheric refractivity leads to an increase in the observed range. These induced propagation delays affect the quality of phase measurement and introduce errors in the topography and deformation fields. The effect of this delay was studied on a differential interferogram (DInSAR. To calculate the amount of tropospheric delay occurred, the meteorological data collected from the Spanish Agencia Estatal de Meteorología (AEMET and MODIS were used. The interferograms generated from Sentinel-1 carrying C-band Synthetic Aperture RADAR Single Look Complex (SLC images acquired on the study area are used. The study area consists of different types of scatterers exhibiting different coherence. The existing Saastamoinen model was used to perform a quantitative evaluation of the phase changes caused by pressure, temperature and humidity of the troposphere during the study. Unless the phase values due to atmospheric disturbances are not corrected, it is difficult to obtain accurate measurements. Thus, the atmospheric error correction is essential for all practical applications of DInSAR to avoid inaccurate

  14. Sleep deprivation decreases phase-shift responses of circadian rhythms to light in the mouse: role of serotonergic and metabolic signals.

    Science.gov (United States)

    Challet, E; Turek, F W; Laute, M; Van Reeth, O

    2001-08-03

    The circadian pacemaker in the suprachiasmatic nuclei is primarily synchronized to the daily light-dark cycle. The phase-shifting and synchronizing effects of light can be modulated by non-photic factors, such as behavioral, metabolic or serotonergic cues. The present experiments examine the effects of sleep deprivation on the response of the circadian pacemaker to light and test the possible involvement of serotonergic and/or metabolic cues in mediating the effects of sleep deprivation. Photic phase-shifting of the locomotor activity rhythm was analyzed in mice transferred from a light-dark cycle to constant darkness, and sleep-deprived for 8 h from Zeitgeber Time 6 to Zeitgeber Time 14. Phase-delays in response to a 10-min light pulse at Zeitgeber Time 14 were reduced by 30% in sleep-deprived mice compared to control mice, while sleep deprivation without light exposure induced no significant phase-shifts. Stimulation of serotonin neurotransmission by fluoxetine (10 mg/kg), a serotonin reuptake inhibitor that decreases light-induced phase-delays in non-deprived mice, did not further reduce light-induced phase-delays in sleep-deprived mice. Impairment of serotonin neurotransmission with p-chloroamphetamine (three injections of 10 mg/kg), which did not increase light-induced phase-delays in non-deprived mice significantly, partially normalized light-induced phase-delays in sleep-deprived mice. Injections of glucose increased light-induced phase-delays in control and sleep-deprived mice. Chemical damage of the ventromedial hypothalamus by gold-thioglucose (600 mg/kg) prevented the reduction of light-induced phase-delays in sleep-deprived mice, without altering phase-delays in control mice. Taken together, the present results indicate that sleep deprivation can reduce the light-induced phase-shifts of the mouse suprachiasmatic pacemaker, due to serotonergic and metabolic changes associated with the loss of sleep.

  15. Sleep restriction and delayed sleep associate with psychological health and biomarkers of stress and inflammation in women.

    Science.gov (United States)

    Tartar, Jaime L; Fins, Ana I; Lopez, Andrea; Sierra, Linett A; Silverman, Sarah A; Thomas, Samuel V; Craddock, Travis J A

    2015-12-01

    Despite strong associations between sleep duration and health, there is no clear understanding of how volitional chronic sleep restriction (CSR) alters the physiological processes that lead to poor health in women. We focused on biochemical and psychological factors that previous research suggests are essential to uncovering the role of sleep in health. Cross-sectional study. University-based. Sixty female participants (mean age, 19.3; SD, 2.1 years). We analyzed the association between self-reported volitional CSR and time to go to sleep on a series of sleep and psychological health measures as well as biomarkers of immune functioning/inflammation (interleukin [IL]-1β), stress (cortisol), and sleep regulation (melatonin). Across multiple measures, poor sleep was associated with decreased psychological health and a reduced perception of self-reported physical health. Volitional CSR was related to increased cortisol and increased IL-1β levels. We separately looked at individuals who experienced CSR with and without delayed sleep time and found that IL-1β levels were significantly elevated in CSR alone and in CSR combined with a late sleep time. Cortisol, however, was only elevated in those women who experienced CSR combined with a late sleep time. We did not observe any changes in melatonin across groups, and melatonin levels were not related to any sleep measures. New to our study is the demonstration of how an increase in a proinflammatory process and an increase in hypothalamic-pituitary-adrenal axis activity both relate to volitional CSR, with and without a delayed sleep time. We further show how these mechanisms relate back to psychological and self-reported health in young adult women. Copyright © 2015 National Sleep Foundation. Published by Elsevier Inc. All rights reserved.

  16. Longitudinal Outcomes of Start Time Delay on Sleep, Behavior, and Achievement in High School

    Science.gov (United States)

    Thacher, Pamela V.; Onyper, Serge V.

    2016-01-01

    Study Objectives: To establish whether sleep, health, mood, behavior, and academics improved after a 45-minute delay in high school start time, and whether changes persisted longitudinally. Methods: We collected data from school records and student self-report across a number of domains at baseline (May 2012) and at two follow-up time points (November 2012 and May 2013), at a public high school in upstate New York. Students enrolled during academic years (AY) 2011–2012 and 2012–2013 completed the Pittsburgh Sleep Quality Index; the DASS-21; the “Owl-Lark” Scale; the Daytime Sleepiness Index; and a brief self-report of health. Reports from school records regarding attendance, tardiness, disciplinary violations, and academic performance were collected for AY 2010–2011 through 2013–2014. Results: Students delayed but did not extend their sleep period; we found lasting improvements in tardiness and disciplinary violations after the start-time delay, but no changes to other variables. At the first follow-up, students reported 20 minutes longer sleep, driven by later rise times and stable bed times. At the second follow-up, students maintained later rise times but delayed bedtimes, returning total sleep to baseline levels. A delay in rise time, paralleling the delay in the start time that occurred, resulted in less tardiness and decreased disciplinary incidents, but larger improvements to sleep patterns may be necessary to affect health, attendance, sleepiness, and academic performance. Conclusions: Later start times improved tardiness and disciplinary issues at this school district. A delay in start time may be a necessary but not sufficient means to increase sleep time and may depend on preexisting individual differences. Commentary: A commentary on this article appears in this issue on page 267. Citation: Thacher PV, Onyper SV. Longitudinal outcomes of start time delay on sleep, behavior, and achievement in high school. SLEEP 2016;39(2):271–281. PMID

  17. REM Sleep Phase Preference in the Crepuscular Octodon degus Assessed by Selective REM Sleep Deprivation

    Science.gov (United States)

    Ocampo-Garcés, Adrián; Hernández, Felipe; Palacios, Adrian G.

    2013-01-01

    Study Objectives: To determine rapid eye movement (REM) sleep phase preference in a crepuscular mammal (Octodon degus) by challenging the specific REM sleep homeostatic response during the diurnal and nocturnal anticrepuscular rest phases. Design: We have investigated REM sleep rebound, recovery, and documented REM sleep propensity measures during and after diurnal and nocturnal selective REM sleep deprivations. Subjects: Nine male wild-captured O. degus prepared for polysomnographic recordings Interventions: Animals were recorded during four consecutive baseline and two separate diurnal or nocturnal deprivation days, under a 12:12 light-dark schedule. Three-h selective REM sleep deprivations were performed, starting at midday (zeitgeber time 6) or midnight (zeitgeber time 18). Measurements and Results: Diurnal and nocturnal REM sleep deprivations provoked equivalent amounts of REM sleep debt, but a consistent REM sleep rebound was found only after nocturnal deprivation. The nocturnal rebound was characterized by a complete recovery of REM sleep associated with an augment in REM/total sleep time ratio and enhancement in REM sleep episode consolidation. Conclusions: Our results support the notion that the circadian system actively promotes REM sleep. We propose that the sleep-wake cycle of O. degus is modulated by a chorus of circadian oscillators with a bimodal crepuscular modulation of arousal and a unimodal promotion of nocturnal REM sleep. Citation: Ocampo-Garcés A; Hernández F; Palacios AG. REM sleep phase preference in the crepuscular Octodon degus assessed by selective REM sleep deprivation. SLEEP 2013;36(8):1247-1256. PMID:23904685

  18. Impact of delaying school start time on adolescent sleep, mood, and behavior.

    Science.gov (United States)

    Owens, Judith A; Belon, Katherine; Moss, Patricia

    2010-07-01

    To examine the impact of a 30-minute delay in school start time on adolescents' sleep, mood, and behavior. Participants completed the online retrospective Sleep Habits Survey before and after a change in school start time. An independent high school in Rhode Island. Students (n = 201) in grades 9 through 12. Intervention Institution of a delay in school start time from 8 to 8:30 am. Sleep patterns and behavior, daytime sleepiness, mood, data from the Health Center, and absences/tardies. After the start time delay, mean school night sleep duration increased by 45 minutes, and average bedtime advanced by 18 minutes (95% confidence interval, 7-29 minutes [t(423) = 3.36; P students getting less than 7 hours of sleep decreased by 79.4%, and those reporting at least 8 hours of sleep increased from 16.4% to 54.7%. Students reported significantly more satisfaction with sleep and experienced improved motivation. Daytime sleepiness, fatigue, and depressed mood were all reduced. Most health-related variables, including Health Center visits for fatigue-related complaints, and class attendance also improved. A modest delay in school start time was associated with significant improvements in measures of adolescent alertness, mood, and health. The results of this study support the potential benefits of adjusting school schedules to adolescents' sleep needs, circadian rhythm, and developmental stage.

  19. Association between delayed bedtime and sleep-related problems among community-dwelling 2-year-old children in Japan.

    Science.gov (United States)

    Kitamura, Shingo; Enomoto, Minori; Kamei, Yuichi; Inada, Naoko; Moriwaki, Aiko; Kamio, Yoko; Mishima, Kazuo

    2015-03-13

    Although delayed sleep timing causes many socio-psycho-biological problems such as sleep loss, excessive daytime sleepiness, obesity, and impaired daytime neurocognitive performance in adults, there are insufficient data showing the clinical significance of a 'night owl lifestyle' in early life. This study examined the association between habitual delayed bedtime and sleep-related problems among community-dwelling 2-year-old children in Japan. Parents/caregivers of 708 community-dwelling 2-year-old children in Nishitokyo City, Tokyo, participated in the study. The participants answered a questionnaire to evaluate their child's sleep habits and sleep-related problems for the past 1 month. Of the 425 children for whom complete data were collected, 90 (21.2%) went to bed at 22:00 or later. Children with delayed bedtime showed significantly more irregular bedtime, delayed wake time, shorter total sleep time, and difficulty in initiating and terminating sleep. Although this relationship indicated the presence of sleep debt in children with delayed bedtime, sleep onset latency did not differ between children with earlier bedtime and those with delayed bedtime. Rather, delayed bedtime was significantly associated with bedtime resistance and problems in the morning even when adjusting for nighttime and daytime sleep time. Even in 2-year-old children, delayed bedtime was associated with various sleep-related problems. The causal factors may include diminished homeostatic sleep drive due to prolonged daytime nap as well as diurnal preference (morning or night type) regulated by the biological clock.

  20. Longitudinal Outcomes of Start Time Delay on Sleep, Behavior, and Achievement in High School.

    Science.gov (United States)

    Thacher, Pamela V; Onyper, Serge V

    2016-02-01

    To establish whether sleep, health, mood, behavior, and academics improved after a 45-minute delay in high school start time, and whether changes persisted longitudinally. We collected data from school records and student self-report across a number of domains at baseline (May 2012) and at two follow-up time points (November 2012 and May 2013), at a public high school in upstate New York. Students enrolled during academic years (AY) 2011-2012 and 2012-2013 completed the Pittsburgh Sleep Quality Index; the DASS-21; the "Owl-Lark" Scale; the Daytime Sleepiness Index; and a brief self-report of health. Reports from school records regarding attendance, tardiness, disciplinary violations, and academic performance were collected for AY 2010-2011 through 2013-2014. Students delayed but did not extend their sleep period; we found lasting improvements in tardiness and disciplinary violations after the start-time delay, but no changes to other variables. At the first follow-up, students reported 20 minutes longer sleep, driven by later rise times and stable bed times. At the second follow-up, students maintained later rise times but delayed bedtimes, returning total sleep to baseline levels. A delay in rise time, paralleling the delay in the start time that occurred, resulted in less tardiness and decreased disciplinary incidents, but larger improvements to sleep patterns may be necessary to affect health, attendance, sleepiness, and academic performance. Later start times improved tardiness and disciplinary issues at this school district. A delay in start time may be a necessary but not sufficient means to increase sleep time and may depend on preexisting individual differences. A commentary on this article appears in this issue on page 267. © 2016 Associated Professional Sleep Societies, LLC.

  1. Short-term total sleep deprivation alters delay-conditioned memory in the rat.

    Science.gov (United States)

    Tripathi, Shweta; Jha, Sushil K

    2016-06-01

    Short-term sleep deprivation soon after training may impair memory consolidation. Also, a particular sleep stage or its components increase after learning some tasks, such as negative and positive reinforcement tasks, avoidance tasks, and spatial learning tasks, and so forth. It suggests that discrete memory types may require specific sleep stage or its components for their optimal processing. The classical conditioning paradigms are widely used to study learning and memory but the role of sleep in a complex conditioned learning is unclear. Here, we have investigated the effects of short-term sleep deprivation on the consolidation of delay-conditioned memory and the changes in sleep architecture after conditioning. Rats were trained for the delay-conditioned task (for conditioning, house-light [conditioned stimulus] was paired with fruit juice [unconditioned stimulus]). Animals were divided into 3 groups: (a) sleep deprived (SD); (b) nonsleep deprived (NSD); and (c) stress control (SC) groups. Two-way ANOVA revealed a significant interaction between groups and days (training and testing) during the conditioned stimulus-unconditioned stimulus presentation. Further, Tukey post hoc comparison revealed that the NSD and SC animals exhibited significant increase in performances during testing. The SD animals, however, performed significantly less during testing. Further, we observed that wakefulness and NREM sleep did not change after training and testing. Interestingly, REM sleep increased significantly on both days compared to baseline more specifically during the initial 4-hr time window after conditioning. Our results suggest that the consolidation of delay-conditioned memory is sleep-dependent and requires augmented REM sleep during an explicit time window soon after training. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  2. Sleep deprivation accelerates delay-related loss of visual short-term memories without affecting precision.

    Science.gov (United States)

    Wee, Natalie; Asplund, Christopher L; Chee, Michael W L

    2013-06-01

    Visual short-term memory (VSTM) is an important measure of information processing capacity and supports many higher-order cognitive processes. We examined how sleep deprivation (SD) and maintenance duration interact to influence the number and precision of items in VSTM using an experimental design that limits the contribution of lapses at encoding. For each trial, participants attempted to maintain the location and color of three stimuli over a delay. After a retention interval of either 1 or 10 seconds, participants reported the color of the item at the cued location by selecting it on a color wheel. The probability of reporting the probed item, the precision of report, and the probability of reporting a nonprobed item were determined using a mixture-modeling analysis. Participants were studied twice in counterbalanced order, once after a night of normal sleep and once following a night of sleep deprivation. Sleep laboratory. Nineteen healthy college age volunteers (seven females) with regular sleep patterns. Approximately 24 hours of total SD. SD selectively reduced the number of integrated representations that can be retrieved after a delay, while leaving the precision of object information in the stored representations intact. Delay interacted with SD to lower the rate of successful recall. Visual short-term memory is compromised during sleep deprivation, an effect compounded by delay. However, when memories are retrieved, they tend to be intact.

  3. The impact of sleep on true and false memory across long delays.

    Science.gov (United States)

    Pardilla-Delgado, Enmanuelle; Payne, Jessica D

    2017-01-01

    While the influence of sleep on memory has a long history, sleep's role in the formation of false memories is less clear. Moreover, virtually nothing is known about the development of false memories beyond delays of about 12h. Here, for the first time, we assess post-sleep development of true and false memories across longer delay intervals of 24 and 48h. Although technically a false memory, remembering information that is related to the theme, or gist, of an experience can be considered an adaptive process. Some evidence suggests that sleep, compared to a wake period, increases both true and gist-based false memories in the Deese-Roediger-McDermott (DRM) task, but not all studies have returned this result, and most studies cannot rule out the possibility that sleep is merely protecting the information from interference, as opposed to actively aiding its consolidation. Here, to equate amount of time spent awake and asleep across groups, we assess how the positioning of sleep relative to memory encoding impacts retention across longer delays of 24 and 48h. Participants encoded 16 DRM lists in the morning (WAKE 1st Groups) or evening (SLEEP 1st Groups), and were tested either 24 or 48h later at the same time of day. Results demonstrate that true memory is better when participants sleep soon after learning. Sleeping first also increased false memory, but only in low performers. Importantly, and similar to previous studies, we found a negative correlation between slow-wave sleep (SWS) and false memory, suggesting that SWS may be detrimental for semantic/gist processing. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Delay-aware adaptive sleep mechanism for green wireless-optical broadband access networks

    Science.gov (United States)

    Wang, Ruyan; Liang, Alei; Wu, Dapeng; Wu, Dalei

    2017-07-01

    Wireless-Optical Broadband Access Network (WOBAN) is capacity-high, reliable, flexible, and ubiquitous, as it takes full advantage of the merits from both optical communication and wireless communication technologies. Similar to other access networks, the high energy consumption poses a great challenge for building up WOBANs. To shot this problem, we can make some load-light Optical Network Units (ONUs) sleep to reduce the energy consumption. Such operation, however, causes the increased packet delay. Jointly considering the energy consumption and transmission delay, we propose a delay-aware adaptive sleep mechanism. Specifically, we develop a new analytical method to evaluate the transmission delay and queuing delay over the optical part, instead of adopting M/M/1 queuing model. Meanwhile, we also analyze the access delay and queuing delay of the wireless part. Based on such developed delay models, we mathematically derive ONU's optimal sleep time. In addition, we provide numerous simulation results to show the effectiveness of the proposed mechanism.

  5. Delayed school start times and adolescent sleep: A systematic review of the experimental evidence.

    Science.gov (United States)

    Minges, Karl E; Redeker, Nancy S

    2016-08-01

    Many schools have instituted later morning start times to improve sleep, academic, and other outcomes in response to the mismatch between youth circadian rhythms and early morning start times. However, there has been no systematic synthesis of the evidence on the effects of this practice. To examine the impact of delayed school start time on students' sleep, health, and academic outcomes, electronic databases were systematically searched and data were extracted using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Six studies satisfied selection criteria and used pre-post, no control (n = 3), randomized controlled trial (n = 2), and quasi-experimental (n = 1) designs. School start times were delayed 25-60 min, and correspondingly, total sleep time increased from 25 to 77 min per weeknight. Some studies revealed reduced daytime sleepiness, depression, caffeine use, tardiness to class, and trouble staying awake. Overall, the evidence supports recent non-experimental study findings and calls for policy that advocates for delayed school start time to improve sleep. This presents a potential long-term solution to chronic sleep restriction during adolescence. However, there is a need for rigorous randomized study designs and reporting of consistent outcomes, including objective sleep measures and consistent measures of health and academic performance. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Face to phase: pitfalls in time delay estimation from coherency phase

    NARCIS (Netherlands)

    Campfens, S.F.; van der Kooij, Herman; Schouten, Alfred Christiaan

    2014-01-01

    Coherency phase is often interpreted as a time delay reflecting a transmission delay between spatially separated neural populations. However, time delays estimated from corticomuscular coherency are conflicting and often shorter than expected physiologically. Recent work suggests that

  7. Genetic variants in RBFOX3 are associated with sleep latency

    NARCIS (Netherlands)

    N. Amin (Najaf); K.V. Allebrandt; A. van der Spek (Ashley); B. Müller-Myhsok (B.); K. Hek (Karin); M. Teder-Laving (Maris); C. Hayward (Caroline); T. Esko (Tõnu); J. van Mill; H. Mbarek; N.F. Watson (Nathaniel F); S.A. Melville (Scott); F.M. Del Greco (Fabiola); E.M. Byrne (Enda); E. Oole (Edwin); I. Kolcic (Ivana); T.H. Chen; D.S. Evans (Daniel); J. Coresh (Josef); N. Vogelzangs (Nicole); J. Karjalainen (Juha); G.A.H.M. Willemsen (Gonneke); S.A. Gharib (Sina); L. Zgaga (Lina); E. Mihailov (Evelin); K.L. Stone (Katie L); H. Campbell (Harry); R.W.W. Brouwer (Rutger); A. Demirkan (Ayşe); A.J. Isaacs (Aaron); Z. Dogas; K. Marciante (Kristin); S. Campbell (Susan); F. Borovecki (Fran); A.I. Luik (Annemarie I); M. Li (Man); J.J. Hottenga (Jouke Jan); J.E. Huffman (Jennifer); M.C.G.N. van den hout (Mirjam); S.R. Cummings (Steven R.); Y.S. Aulchenko (Yurii); P.R. Gehrman (Philip); A.G. Uitterlinden (André); H.E. Wichmann (Heinz Erich); M. Müller-Nurasyid (Martina); R.S.N. Fehrmann (Rudolf); G.W. Montgomery (Grant); A. Hofman (Albert); W.H.L. Kao (Wen Hong Linda); B.A. Oostra (Ben); A. Wright (Alan); J.M. Vink (Jacqueline); J.F. Wilson (James F); P.P. Pramstaller (Peter Paul); A.A. Hicks (Andrew); O. Polasek (Ozren); N.M. Punjabi (Naresh); S. Redline (Susan); B.M. Psaty (Bruce); A.C. Heath (Andrew C.); M. Merrow; G.J. Tranah (Gregory); D.J. Gottlieb (Daniel J); D.I. Boomsma (Dorret); N.G. Martin (Nicholas); I. Rudan (Igor); H.W. Tiemeier (Henning); W.F.J. van IJcken (Wilfred); B.W.J.H. Penninx; A. Metspalu (Andres); T. Meitinger (Thomas); L. Franke (Lude); T. Roenneberg; C.M. van Duijn (Cornelia)

    2016-01-01

    textabstractTime to fall asleep (sleep latency) is a major determinant of sleep quality. Chronic, long sleep latency is a major characteristic of sleep-onset insomnia and/or delayed sleep phase syndrome. In this study we aimed to discover common polymorphisms that contribute to the genetics of sleep

  8. Genetic variants in RBFOX3 are associated with sleep latency

    NARCIS (Netherlands)

    Amin, N.; Allebrandt, K.V.; Spek, A.; Müller-Myhsok, B.; Hek, K.; Teder-Laving, M.; Hayward, C.; Esko, T.; van Mill, J.G.; Mbarek, H.; Watson, N.F.; Melville, S.A.; Del Greco, M.F.; Byrne, E.M.; Oole, E.; Kolcic, I.; Chen, T.; Evans, D.S.; Coresh, J.; Vogelzangs, N.; Karjalainen, J.; Willemsen, G.; Gharib, S.A.; Zgaga, L.; Mihailov, E.; Stone, K.L.; Campbell, H.; Brouwer, R.W.W.; Demirkan, A.; Isaacs, A.; Dogas, Z.; Marciante, K.; Campbell, S.; Borovecki, F.; Luik, A.I.; Li, M.; Hottenga, J.J.; Huffman, J.E.; van den Hout, M.C.G.N.; Cummings, S.R.; Aulchenko, Y.S.; Gehrman, P.R.; Uitterlinden, A.G.; Wichmann, H.E.; Müller-Nurasyid, M.; Fehrmann, R.S.N.; Montgomery, G.W.; Hofman, A.; Hong, W.; Kao, L.; Oostra, B.A.; Wright, A.F.; Vink, J.M.; Wilson, J.F.; Pramstaller, P.P.; Hicks, A.A.; Polasek, O.; Punjabi, N.M.; Redline, S.; Psaty, B.M.; Heath, A.C.; Merrow, M.; Tranah, G.J.; Gottlieb, D.J.; Boomsma, D.I.; Martin, N.G.; Rudan, I.; Tiemeier, H.; van Ijcken, W.F.J.; Penninx, B.W.J.H.; Metspalu, A.; Meitinger, T.; Franke, L.; Roenneberg, T.; van Duijn, C.M.

    2016-01-01

    Time to fall asleep (sleep latency) is a major determinant of sleep quality. Chronic, long sleep latency is a major characteristic of sleep-onset insomnia and/or delayed sleep phase syndrome. In this study we aimed to discover common polymorphisms that contribute to the genetics of sleep latency. We

  9. Virtual unit delay for digital frequency adaptive T/4 delay phase-locked loop system

    DEFF Research Database (Denmark)

    Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede

    2016-01-01

    /processor with a fixed sampling rate considering the cost and complexity, where the number of unit delays that have been adopted should be an integer. For instance, in conventional digital control systems, a single-phase T/4 Delay Phase-Locked Loop (PLL) system takes 50 unit delays (i.e., in a 50-Hz system...... Delay PLL system should be done in its implementation. This process will result in performance degradation in the digital control system, as the exactly required number of delays is not realized. Hence, in this paper, a Virtual Unit Delay (VUD) has been proposed to address such challenges to the digital......Digital micro-controllers/processors enable the cost-effective control of grid-connected power converter systems in terms of system monitoring, signal processing (e.g., grid synchronization), control (e.g., grid current and voltage control), etc. Normally, the control is implemented in a micro-controller...

  10. Two pedigrees of familial advanced sleep phase syndrome in Japan.

    Science.gov (United States)

    Satoh, Kohtoku; Mishima, Kazuo; Inoue, Yuichi; Ebisawa, Takashi; Shimizu, Tetsuo

    2003-06-15

    To determine whether a known missense mutation (bp2106 A/G) in hPer2 (a human homolog of the Drosophila period gene) for familial advanced sleep phase syndrome in a Caucasian family is involved in Japanese familial advanced sleep phase syndrome pedigrees. We identified 2 new Japanese families with advanced sleep phase syndrome, and a systematic survey was carried out in 28 relatives of theses 2 families. A total of 9 affected subjects were identified. The affected members showed significantly strong morningness tendencies compared with the unaffected members in various circadian parameters including the Horne-Ostberg Morningness-Eveningness Questionnaire score (77.3 +/- 4.8 vs 57.5 +/- 7.6, p sleep-onset time (20:45 +/- 75 min vs 23:16 +/- 64 min, p DNA samples were obtained from 7 affected and 7 unaffected subjects. None of the tested subjects possessed the missense mutation (bp2106 A/G) in hPer2. Furthermore, there is no significant linkage between affected subjects with hPer2 region by 2-point mapping and by direct sequencing of 23 exons of hPer2. These findings support the notion of genetic heterogeneity of familial advanced sleep phase syndrome cases in humans. The search for more familial advanced sleep phase syndrome cases and for loci other than hPer2 are necessary to further examine the roles of circadian-related genes in genetically determined human circadian rhythm disorders.

  11. Parkinsonian syndromes presenting with circadian rhythm sleep disorder- advanced sleep-phase type.

    Science.gov (United States)

    Shukla, Garima; Kaul, Bhavna; Gupta, Anupama; Goyal, Vinay; Behari, Madhuri

    2015-01-01

    Circadian rhythm sleep disorder-advanced sleep-phase type is a relatively uncommon disorder, mostly seen among the elderly population. Impaired circadian rhythms have been reported in neurodegenerative conditions; however, there are no reports of any circadian rhythm sleep disorder among patients with Parkinsonian syndromes. We report two patients who presented with this circadian rhythm disorder, and were then diagnosed with a Parkinsonian syndrome. The cases. A 65-year-old retired man presented with history of abrupt change in sleep schedules, sleeping around 6.30-7 p.m. and waking up around 3-4 a.m. for the last 2 months. On detailed examination, the patient was observed to have symmetrical bradykinesia and cogwheel rigidity of limbs. A diagnosis of multiple system atrophy was made, supported by MRI findings and evidence of autonomic dysfunction. Symptoms of change in sleep-wake cycles resolved over the next 1 year, while the patient was treated with dopaminergic therapy. A 47-year-old man, who was being evaluated for presurgical investigation for refractory temporal lobe epilepsy, presented with complaints suggestive of dysarthria, bradykinesia of limbs and frequent falls for 5 months. Simultaneously, he began to sleep around 7 p.m. and wake up at about 2-3 a.m. Examination revealed severe axial rigidity, restricted vertical gaze and bradykinesia of limbs. A diagnosis of progressive supranuclear palsy was made. This is the first report of Parkinson's plus syndromes presenting with a circadian rhythm sleep disorder-advanced sleep-phase type. More prospective assessment for circadian sleep disorders may introduce useful insights into similar associations. Copyright 2015, NMJI.

  12. Sleep deprivation alters effort discounting but not delay discounting of monetary rewards.

    Science.gov (United States)

    Libedinsky, Camilo; Massar, Stijn A A; Ling, Aiqing; Chee, Weiyan; Huettel, Scott A; Chee, Michael W L

    2013-06-01

    To determine whether sleep deprivation would affect the discounting of delayed rewards, of rewards entailing the expense of effort, or both. We measured rates of two types of reward discounting under conditions of rested wakefulness (RW) and sleep deprivation (SD). Delay discounting was defined as the willingness to accept smaller monetary rewards sooner rather than larger monetary rewards later. Effort discounting was defined as the willingness to accept smaller rewards that require less effort to obtain (e.g., typing a small number of letter strings backward) over larger but more effortful rewards (e.g., typing more letter strings to receive the reward). The first two experiments used a crossover design in which one session was conducted after a normal night of sleep (RW), and the other after a night without sleep (SD). The first experiment evaluated only temporal discounting whereas the second evaluated temporal and effort discounting. In the second experiment, the discounting tasks were repeatedly administered prior to the state comparisons to minimize the effects of order and/or repeated testing. In a third experiment, participants were studied only once in a between-subject evaluation of discounting across states. The study took place in a research laboratory. Seventy-seven healthy young adult participants: 20 in Experiment 1, 27 in Experiment 2, and 30 in Experiment 3. N/A. Sleep deprivation elicited increased effort discounting but did not affect delay discounting. The dissociable effects of sleep deprivation on two forms of discounting behavior suggest that they may have differing underlying neural mechanisms.

  13. Sleep/wake scheduling scheme for minimizing end-to-end delay in multi-hop wireless sensor networks

    OpenAIRE

    Madani Sajjad; Nazir Babar; Hasbullah Halabi

    2011-01-01

    Abstract We present a sleep/wake schedule protocol for minimizing end-to-end delay for event driven multi-hop wireless sensor networks. In contrast to generic sleep/wake scheduling schemes, our proposed algorithm performs scheduling that is dependent on traffic loads. Nodes adapt their sleep/wake schedule based on traffic loads in response to three important factors, (a) the distance of the node from the sink node, (b) the importance of the node's location from connectivity's perspective, and...

  14. Electroencephalogram Power Density and Slow Wave Sleep as a Function of Prior Waking and Circadian Phase

    NARCIS (Netherlands)

    Dijk, Derk-Jan; Brunner, Daniel P.; Beersma, Domien G.M.; Borbély, Alexander A.

    1990-01-01

    Human sleep electroencephalograms, recorded in four experiments, were subjected to spectral analysis. Waking prior to sleep varied from 12 to 36 h and sleep was initiated at different circadian phases. Power density of delta and theta frequencies in rapid-eye-movement (REM) sleep and non-REM (NREM)

  15. Determination of Uncalibrated Phase Delays for Real-Time PPP

    Science.gov (United States)

    Hinterberger, Fabian; Weber, Robert; Huber, Katrin; Lesjak, Roman

    2014-05-01

    Today PPP is a well-known technique of GNSS based positioning used for a wide range of post-processing applications. Using observations of a single GNSS receiver and applying precise orbit and clock information derived from global GNSS networks highly precise positions can be obtained. The atmospheric delays are usually mitigated by linear combination (ionosphere) and parameter estimation (troposphere). Within the last years also the demand for real-time PPP increased. In 2012, the IGS real-time working group started a pilot project to broadcast real-time precise orbits and clock correction streams. Nevertheless, real-time PPP is in its starting phase and currently only few applications make use of the technique although SSR-Messages are already implemented in RTCM3.1. The problems of still limited accuracy compared to Network-RTK as well as long convergence times might be solved by almost instantaneous integer ambiguity resolution at zero-difference level which is a major topic of current scientific investigations. Therefore a national consortium has carried out over the past 2 years the research project PPP-Serve (funded by the Austrian Research Promotion Agency - FFG), which aimed at the development of appropriate algorithms for real-time PPP with special emphasis on the ambiguity resolution of zero-difference observations. We have established a module which calculates based on GPS-reference station data-streams of a dense network (obtained from IGS via BKG) so-called wide-lane and narrow-lane satellite specific calibration phase delays. While the wide-lane phase delays are almost stable over longer periods, the estimation of narrow-lane phase delays has to be re-established every 24 hours. These phase-delays are submitted via a real-time module to the rover where they are used for point positioning via a PPP-model. This presentation deals with the process and obstacles of calculating the wide-lane and narrow-lane phase-delays (based on SD -observations between

  16. Optical True Time Delay for Phased Array Antennas Composed of 2×2 Optical MEMS Switches and Fiber Delay Lines

    Institute of Scientific and Technical Information of China (English)

    Back-Song; Lee; Jong-Dug; Shin; Boo-Gyoun; Kim

    2003-01-01

    We proposed an optical true time delay (TTD) for phased array antennas (PAAs) composed of 2×2 optical MEMS switches, single-mode fiber delay lines, and a fixed wavelength laser diode. A 3-bit TTD for 10 GHz PAAs was implemented with a time delay error less than ± 0.2 ps.

  17. Effects of lunar phase on sleep in men and women in Surrey.

    Science.gov (United States)

    Della Monica, Ciro; Atzori, Giuseppe; Dijk, Derk-Jan

    2015-12-01

    Recently, evidence has emerged that the phases of the moon may modulate subjective sleep quality and polysomnographically assessed sleep structure in humans. We aimed to explore further the putative effects of circa-lunar periodicity (~29.5 days) on subjective and objective parameters of human sleep in a retrospective analysis. The baseline sleep recordings of 205 (91 males and 114 females; mean age = 47.47 years, standard deviation =19.01; range: 20-84 years) healthy and carefully screened participants who participated in two clinical trials in the Surrey Clinical Research Centre were included in the analyses. Sleep was recorded in windowless sleep laboratories. For each study night, we calculated the distance, in days, to the date of the closest full moon phase and based on this distance, classified sleep records in three lunar classes. Univariate analysis of variance with factors lunar class, age and sex was applied to each of 21 sleep parameters. No significant main effect for the factor lunar class was observed for any of the objective sleep parameters and subjective sleep quality but some significant interactions were observed. The interaction between lunar class and sex was significant for total sleep time, Stage 4 sleep and rapid eye movement (REM) sleep. Separate analyses for men and women indicated that in women total sleep time, Stage 4 sleep and REM sleep were reduced when sleep occurred close to full moon, whereas in men REM duration increased around full moon. These data provide limited evidence for an effect of lunar phase on human sleep. © 2015 European Sleep Research Society.

  18. Classical conditioning for preserving the effects of short melatonin treatment in children with delayed sleep: a pilot study

    Directory of Open Access Journals (Sweden)

    van Maanen A

    2017-03-01

    Full Text Available Annette van Maanen,1 Anne Marie Meijer,1 Marcel G Smits,2 Frans J Oort1 1Research Institute Child Development and Education, University of Amsterdam, Amsterdam, 2Centre for Sleep-Wake Disorders and Chronobiology, Hospital Gelderse Vallei, Ede, the Netherlands Abstract: Melatonin treatment is effective in treating sleep onset problems in children with delayed melatonin onset, but effects usually disappear when treatment is discontinued. In this pilot study, we investigated whether classical conditioning might help in preserving treatment effects of melatonin in children with sleep onset problems, with and without comorbid attention deficit hyperactivity disorder (ADHD or autism. After a baseline week, 16 children (mean age: 9.92 years, 31% ADHD/autism received melatonin treatment for 3 weeks and then gradually discontinued the treatment. Classical conditioning was applied by having children drink organic lemonade while taking melatonin and by using a dim red light lamp that was turned on when children went to bed. Results were compared with a group of 41 children (mean age: 9.43 years, 34% ADHD/autism who received melatonin without classical conditioning. Melatonin treatment was effective in advancing dim light melatonin onset and reducing sleep onset problems, and positive effects were found on health and behavior problems. After stopping melatonin, sleep returned to baseline levels. We found that for children without comorbidity in the experimental group, sleep latency and sleep start delayed less in the stop week, which suggests an effect of classical conditioning. However, classical conditioning seems counterproductive in children with ADHD or autism. Further research is needed to establish these results and to examine other ways to preserve melatonin treatment effects, for example, by applying morning light. Keywords: melatonin, classical conditioning, children, delayed sleep

  19. Confounding effects of phase delays on causality estimation.

    Directory of Open Access Journals (Sweden)

    Vasily A Vakorin

    Full Text Available Linear and non-linear techniques for inferring causal relations between the brain signals representing the underlying neuronal systems have become a powerful tool to extract the connectivity patterns in the brain. Typically these tools employ the idea of Granger causality, which is ultimately based on the temporal precedence between the signals. At the same time, phase synchronization between coupled neural ensembles is considered a mechanism implemented in the brain to integrate relevant neuronal ensembles to perform a cognitive or perceptual task. Phase synchronization can be studied by analyzing the effects of phase-locking between the brain signals. However, we should expect that there is no one-to-one mapping between the observed phase lag and the time precedence as specified by physically interacting systems. Specifically, phase lag observed between two signals may interfere with inferring causal relations. This could be of critical importance for the coupled non-linear oscillating systems, with possible time delays in coupling, when classical linear cross-spectrum strategies for solving phase ambiguity are not efficient. To demonstrate this, we used a prototypical model of coupled non-linear systems, and compared three typical pipelines of inferring Granger causality, as established in the literature. Specifically, we compared the performance of the spectral and information-theoretic Granger pipelines as well as standard Granger causality in their relations to the observed phase differences for frequencies at which the signals become synchronized to each other. We found that an information-theoretic approach, which takes into account different time lags between the past of one signal and the future of another signal, was the most robust to phase effects.

  20. Cumulative phase delay imaging for contrast-enhanced ultrasound tomography

    International Nuclear Information System (INIS)

    Demi, Libertario; Van Sloun, Ruud J G; Wijkstra, Hessel; Mischi, Massimo

    2015-01-01

    Standard dynamic-contrast enhanced ultrasound (DCE-US) imaging detects and estimates ultrasound-contrast-agent (UCA) concentration based on the amplitude of the nonlinear (harmonic) components generated during ultrasound (US) propagation through UCAs. However, harmonic components generation is not specific to UCAs, as it also occurs for US propagating through tissue. Moreover, nonlinear artifacts affect standard DCE-US imaging, causing contrast to tissue ratio reduction, and resulting in possible misclassification of tissue and misinterpretation of UCA concentration. Furthermore, no contrast-specific modality exists for DCE-US tomography; in particular speed-of-sound changes due to UCAs are well within those caused by different tissue types. Recently, a new marker for UCAs has been introduced. A cumulative phase delay (CPD) between the second harmonic and fundamental component is in fact observable for US propagating through UCAs, and is absent in tissue. In this paper, tomographic US images based on CPD are for the first time presented and compared to speed-of-sound US tomography. Results show the applicability of this marker for contrast specific US imaging, with cumulative phase delay imaging (CPDI) showing superior capabilities in detecting and localizing UCA, as compared to speed-of-sound US tomography. Cavities (filled with UCA) which were down to 1 mm in diameter were clearly detectable. Moreover, CPDI is free of the above mentioned nonlinear artifacts. These results open important possibilities to DCE-US tomography, with potential applications to breast imaging for cancer localization. (fast track communication)

  1. Sleep/wake scheduling scheme for minimizing end-to-end delay in multi-hop wireless sensor networks

    Directory of Open Access Journals (Sweden)

    Madani Sajjad

    2011-01-01

    Full Text Available Abstract We present a sleep/wake schedule protocol for minimizing end-to-end delay for event driven multi-hop wireless sensor networks. In contrast to generic sleep/wake scheduling schemes, our proposed algorithm performs scheduling that is dependent on traffic loads. Nodes adapt their sleep/wake schedule based on traffic loads in response to three important factors, (a the distance of the node from the sink node, (b the importance of the node's location from connectivity's perspective, and (c if the node is in the proximity where an event occurs. Using these heuristics, the proposed scheme reduces end-to-end delay and maximizes the throughput by minimizing the congestion at nodes having heavy traffic load. Simulations are carried out to evaluate the performance of the proposed protocol, by comparing its performance with S-MAC and Anycast protocols. Simulation results demonstrate that the proposed protocol has significantly reduced the end-to-end delay, as well as has improved the other QoS parameters, like average energy per packet, average delay, packet loss ratio, throughput, and coverage lifetime.

  2. Circadian distribution of sleep phases after major abdominal surgery

    DEFF Research Database (Denmark)

    Gogenur, I.; Wildschiotz, G.; Rosenberg, J.

    2008-01-01

    Background. It is believed that the severely disturbed night-time sleep architecture after surgery is associated with increased cardiovascular morbidity with rebound of rapid eye movement (REM). The daytime sleep pattern of patients after major general surgery has not been investigated before. We...... nights after operation. Sleep was scored independently by two blinded observers and the recordings were reported as awake, light sleep (LS, stages I and II), slow wave sleep (SWS, stages III and IV), and REM sleep. Results. There was significantly increased REM sleep (P=0.046), LS (P=0.020), and reduced...... time awake (P=0.016) in the postoperative daytime period compared with the preoperative daytime period. Five patients had REM sleep during the daytime after surgery. Three of these patients did not have REM sleep during the preceding postoperative night. There was significantly reduced night-time REM...

  3. Short-Term Sleep Disturbance-Induced Stress Does not Affect Basal Pain Perception, but Does Delay Postsurgical Pain Recovery.

    Science.gov (United States)

    Wang, Po-Kai; Cao, Jing; Wang, Hongzhen; Liang, Lingli; Zhang, Jun; Lutz, Brianna Marie; Shieh, Kun-Ruey; Bekker, Alex; Tao, Yuan-Xiang

    2015-11-01

    Chronic sleep disturbance-induced stress is known to increase basal pain sensitivity. However, most surgical patients frequently report short-term sleep disturbance/deprivation during the pre- and postoperation periods and have normal pain perception presurgery. Whether this short-term sleep disturbance affects postsurgical pain is elusive. Here, we report that pre- or postexposure to rapid eye movement sleep disturbance (REMSD) for 6 hours daily for 3 consecutive days did not alter basal responses to mechanical, heat, and cold stimuli, but did delay recovery in incision-induced reductions in paw withdrawal threshold to mechanical stimulation and paw withdrawal latencies to heat and cold stimuli on the ipsilateral side of male or female rats. This short-term REMSD led to stress shown by an increase in swim immobility time, a decrease in sucrose consumption, and an increase in the level of corticosterone in serum. Blocking this stress via intrathecal RU38486 or bilateral adrenalectomy abolished REMSD-caused delay in recovery of incision-induced reductions in behavioral responses to mechanical, heat, and cold stimuli. Moreover, this short-term REMSD produced significant reductions in the levels of mu opioid receptor and kappa opioid receptor, but not Kv1.2, in the ipsilateral L4/5 spinal cord and dorsal root ganglia on day 9 after incision (but not after sham surgery). Our findings show that short-term sleep disturbance either pre- or postsurgery does not alter basal pain perception, but does exacerbate postsurgical pain hypersensitivity. The latter may be related to the reductions of mu and kappa opioid receptors in the spinal cord and dorsal root ganglia caused by REMSD plus incision. Prevention of short-term sleep disturbance may help recovery from postsurgical pain in patients. Copyright © 2015 American Pain Society. Published by Elsevier Inc. All rights reserved.

  4. Sleep

    Science.gov (United States)

    ... Institute (NHLBI). 1 Mood. Sleep affects your mood. Insufficient sleep can cause irritability that can lead to trouble with relationships, ... basics/understanding_sleep.htm#dynamic_activity Centers for Disease ... insufficient rest or sleep among adults—United States, 2008. MMWR, 58 (42), ...

  5. Trajectories of sleep changes during the acute phase of traumatic brain injury: A 7-day actigraphy study

    Directory of Open Access Journals (Sweden)

    Hsiao-Yean Chiu

    2013-09-01

    Conclusion: Poor sleep efficiency and longer sleep duration are common symptoms in acute TBI patients. Both head injury severity and age predicted the trajectories of daytime and 24-hour sleep duration during the acute phase of TBI, whereas gender predicted the trajectories of 24-hour sleep duration in the mild TBI subgroup.

  6. Sleep supports cued fear extinction memory consolidation independent of circadian phase.

    Science.gov (United States)

    Melo, Irene; Ehrlich, Ingrid

    2016-07-01

    Sleep promotes memory, particularly for declarative learning. However, its role in non-declarative, emotional memories is less well understood. Some studies suggest that sleep may influence fear-related memories, and thus may be an important factor determining the outcome of treatments for emotional disorders such as post-traumatic stress disorder. Here, we investigated the effect of sleep deprivation and time of day on fear extinction memory consolidation. Mice were subjected to a cued Pavlovian fear and extinction paradigm at the beginning of their resting or active phase. Immediate post-extinction learning sleep deprivation for 5h compromised extinction memory when tested 24h after learning. Context-dependent extinction memory recall was completely prevented by sleep-manipulation during the resting phase, while impairment was milder during the active phase and extinction memory retained its context-specificity. Importantly, control experiments excluded confounding factors such as differences in baseline locomotion, fear generalization and stress hormone levels. Together, our findings indicate that post-learning sleep supports cued fear extinction memory consolidation in both circadian phases. The lack of correlation between memory efficacy and sleep time suggests that extinction memory may be influenced by specific sleep events in the early consolidation period. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. A clock and data recovery method based on phase detector implemented by delay chain in FPGA

    International Nuclear Information System (INIS)

    Xie Mingpu; Wu Jie; Zhang Jie

    2009-01-01

    A clock and data recovery method based on charge pump PLL was developed to archive medium data rate serial digital communication with simple line transceivers. The phase detector was realized by FPGA. A delay chain was constructed by delay elements with the same fixed delay. Every output of the delay elements was latched by the VCO output clock when the input signal went through the delay chain. The latched result was used to detect the data transition, which reflected the phase difference between the input signal and the VCO output clock. The VCO control voltage was adjust by charge pump to reduce the phase difference and archive phase lock. The loop filter was a passive filter,parameters of which were calculated from parameters of the delay chain and VCO. The experimental result shows that the clock of a 64Mbps transmission was recovered with a jitter less than 200 ps. (authors)

  8. Multiple-region directed functional connectivity based on phase delays.

    Science.gov (United States)

    Goelman, Gadi; Dan, Rotem

    2017-03-01

    Network analysis is increasingly advancing the field of neuroimaging. Neural networks are generally constructed from pairwise interactions with an assumption of linear relations between them. Here, a high-order statistical framework to calculate directed functional connectivity among multiple regions, using wavelet analysis and spectral coherence has been presented. The mathematical expression for 4 regions was derived and used to characterize a quartet of regions as a linear, combined (nonlinear), or disconnected network. Phase delays between regions were used to obtain network's temporal hierarchy and directionality. The validity of the mathematical derivation along with the effects of coupling strength and noise on its outcomes were studied by computer simulations of the Kuramoto model. The simulations demonstrated correct directionality for a large range of coupling strength and low sensitivity to Gaussian noise compared with pairwise coherences. The analysis was applied to resting-state fMRI data of 40 healthy young subjects to characterize the ventral visual system, motor system and default mode network (DMN). It was shown that the ventral visual system was predominantly composed of linear networks while the motor system and the DMN were composed of combined (nonlinear) networks. The ventral visual system exhibits its known temporal hierarchy, the motor system exhibits center ↔ out hierarchy and the DMN has dorsal ↔ ventral and anterior ↔ posterior organizations. The analysis can be applied in different disciplines such as seismology, or economy and in a variety of brain data including stimulus-driven fMRI, electrophysiology, EEG, and MEG, thus open new horizons in brain research. Hum Brain Mapp 38:1374-1386, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  9. Impact of menstrual cycle phase on endocrine effects of partial sleep restriction in healthy women.

    Science.gov (United States)

    LeRoux, Amanda; Wright, Lisa; Perrot, Tara; Rusak, Benjamin

    2014-11-01

    There is extensive evidence that sleep restriction alters endocrine function in healthy young men, increasing afternoon cortisol levels and modifying levels of other hormones that regulate metabolism. Recent studies have confirmed these effects in young women, but have not investigated whether menstrual cycle phase influences these responses. The effects on cortisol levels of limiting sleep to 3h for one night were assessed in two groups of women at different points in their menstrual cycles: mid-follicular and mid-luteal. Eighteen healthy, young women, not taking oral contraceptives (age: 21.8±0.53; BMI: 22.5±0.58 [mean±SEM]), were studied. Baseline sleep durations, eating habits and menstrual cycles were monitored. Salivary samples were collected at six times of day (08:00, 08:30, 11:00, 14:00, 17:00, 20:00) during two consecutive days: first after a 10h overnight sleep opportunity (Baseline) and then after a night with a 3h sleep opportunity (Post-sleep restriction). All were awakened at the same time of day. Women in the follicular phase showed a significant decrease (p=0.004) in their cortisol awakening responses (CAR) after sleep restriction and a sustained elevation in afternoon/evening cortisol levels (p=0.008), as has been reported for men. Women in the luteal phase showed neither a depressed CAR, nor an increase in afternoon/evening cortisol levels. Secondary analyses examined the impact of sleep restriction on self-reported hunger and mood. Menstrual cycle phase dramatically altered the cortisol responses of healthy, young women to a single night of sleep restriction, implicating effects of spontaneous changes in endocrine status on adrenal responses to sleep loss. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Advanced gastric cancer. The findings of delayed phase dynamic CT and radiologic-histopathologic correlation

    International Nuclear Information System (INIS)

    Monzawa, Shuichi; Omata, Kosaku; Nakazima, Hiroto; Yokosuka, Noriko; Ito, Atuko; Araki, Tsutomu

    2000-01-01

    The aim of this study was to describe delayed phase dynamic CT findings of advanced (T2-T4) gastric cancer and to correlate with histopathologic findings. Quadruple phase dynamic CT including delayed imaging taken five minutes after the start of injection of contrast material was performed in 43 patients with 45 advanced gastric cancer and 20 control subjects with no gastric lesions. On delayed phase CT scans, the attenuation of the gastric wall was equal to or lower than that of the liver parenchyma in the control subjects, therefore, the presence of higher attenuation in the gastric wall was considered to be abnormal and defined as delayed enhancement. Histopathologic findings in the tumors showing delayed enhancement were compared with those in the tumors without this feature. Delayed enhancement was seen in 26 (57%) of the 45 tumors. Eleven of 25 differentiated-type tumors and 15 of 20 undifferentiated-type tumors showed delayed enhancement (p<.05). Delayed enhancement was seen in one of five medullary type tumors, in 11 of 25 intermediate-type tumors, and in 14 of 15 scirrhous-type tumors (p<.005). Delayed enhancement was frequently seen in the tumors with abundant fibrous tissue stroma. Delayed phase dynamic CT may be useful for the characterization of advanced gastric cancer. (author)

  11. Sleep quality in medical students: a comparison across the various phases of the medical course

    Science.gov (United States)

    Corrêa, Camila de Castro; de Oliveira, Felipe Kazan; Pizzamiglio, Diego Scherlon; Ortolan, Erika Veruska Paiva; Weber, Silke Anna Theresa

    2017-01-01

    ABSTRACT Objective: To evaluate and compare subjective sleep quality in medical students across the various phases of the medical course. Methods: This was a cross-sectional study involving medical undergraduates at one medical school in the city of Botucatu, Brazil. All first- to sixth-year students were invited to complete the Pittsburgh Sleep Quality Index, which has been validated for use in Brazil. Participants were divided into three groups according to the phase of the medical course: group A (first- and second-years); group B (third- and fourth-years); and group C (fifth- and sixth-years). The results obtained for the instrument components were analyzed for the total sample and for the groups. Results: Of the 540 students invited to participate, 372 completed the instrument fully. Of those, 147 (39.5%) reported their sleep quality to be either very or fairly bad; 110 (29.5%) reported taking more than 30 min to fall asleep; 253 (68.0%) reported sleeping 6-7 h per night; 327 (87.9%) reported adequate sleep efficiency; 315 (84.6%) reported no sleep disturbances; 32 (8.6%) reported using sleeping medication; and 137 (36.9%) reported difficulty staying awake during the day at least once a week. Group comparison revealed that students in group A had worse subjective sleep quality and greater daytime dysfunction than did those in groups B and C. Conclusions: Medical students seem to be more exposed to sleep disturbance than other university students, and first- and second-years are more affected than those in other class years because they have worse subjective sleep quality. Active interventions should be implemented to improve sleep hygiene in medical students. PMID:29365004

  12. Wearable Device for Objective Sleep Monitoring, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA has a critical requirement for a wearable device that can provide objective measures of sleep and activity for its crew during long duration spaceflight. In the...

  13. Phase models and clustering in networks of oscillators with delayed coupling

    Science.gov (United States)

    Campbell, Sue Ann; Wang, Zhen

    2018-01-01

    We consider a general model for a network of oscillators with time delayed coupling where the coupling matrix is circulant. We use the theory of weakly coupled oscillators to reduce the system of delay differential equations to a phase model where the time delay enters as a phase shift. We use the phase model to determine model independent existence and stability results for symmetric cluster solutions. Our results extend previous work to systems with time delay and a more general coupling matrix. We show that the presence of the time delay can lead to the coexistence of multiple stable clustering solutions. We apply our analytical results to a network of Morris Lecar neurons and compare these results with numerical continuation and simulation studies.

  14. Delaying Middle School and High School Start Times Promotes Student Health and Performance: An American Academy of Sleep Medicine Position Statement.

    Science.gov (United States)

    Watson, Nathaniel F; Martin, Jennifer L; Wise, Merrill S; Carden, Kelly A; Kirsch, Douglas B; Kristo, David A; Malhotra, Raman K; Olson, Eric J; Ramar, Kannan; Rosen, Ilene M; Rowley, James A; Weaver, Terri E; Chervin, Ronald D

    2017-04-15

    During adolescence, internal circadian rhythms and biological sleep drive change to result in later sleep and wake times. As a result of these changes, early middle school and high school start times curtail sleep, hamper a student's preparedness to learn, negatively impact physical and mental health, and impair driving safety. Furthermore, a growing body of evidence shows that delaying school start times positively impacts student achievement, health, and safety. Public awareness of the hazards of early school start times and the benefits of later start times are largely unappreciated. As a result, the American Academy of Sleep Medicine is calling on communities, school boards, and educational institutions to implement start times of 8:30 AM or later for middle schools and high schools to ensure that every student arrives at school healthy, awake, alert, and ready to learn. © 2017 American Academy of Sleep Medicine

  15. Sleep Comfort Evaluation in Bedding that Utilized Phase Change Materials (PCM)

    OpenAIRE

    橋本, 一馬; 青井, 政貴; 吉田, 宏昭; 上條, 正義

    2015-01-01

    The purpose of this study is to reveal the bedding influence degree to quality of sleep. This bedding utilized Phase Change Materials (PCM). We carried out two experiments. Firstly, we experimentally confirmed thermal properties of the PCM. Secondly, we carried out overnight sleep experiment in hot and cold environment. We prepared the PCM bedding and normal bedding that is commercially-supplied. Consequently, the PCM had been the property of cold tactile sensation rather than the normal bedd...

  16. The comparing results of carcinoma between three-phase and delayed whole body bone scan

    International Nuclear Information System (INIS)

    Si Hongwei; Li Xianfeng

    2004-01-01

    Purpose: Three phase bone scan is an imaging technology in nuclear medicine, which composed of blood flow phase, blood pool phase and delayed phase and the last one is often performed in routine works in department of nuclear medicine. The purpose of this study is to evaluate the merit of three-phase bone scan.Methods: In this study, we chose 54 patients who were having an regional pain which caused by benign or malignant carcinoma that diagnosed by CT, X-ray, ECT, MRI or other examinations. The imaging were acquired simultaneously from both anterior and posterior views, after a bolus injection of 1110 MBq technetium-99m-labelled methylene diphosphonate (MDP), blood phase contains 20 frame sand 3 seconds per frame, blood pool phase contains 5 frames and 1 minute per frame, delayed phase was performed 2.5 hour later. According to the results of three-phase bone scan, the patients were divided into 2 groups: normal and abnormal groups. The abnormal group includes early phase positive,delay positive and all three phase positive sets. The comparing among the 3 sets were analyzed by chi-square test and other statistic means.Results: There were 54 patients who had suffered lung cancer, breast cancer and other cancer,involved in this study, 34 males and 20 females, ranged age 17 to 88 years, were normal in 15 cases,positive in 22 cases, the results in delayed phase were positive in 9 cases, blood flow and blood pool phase showed blood flow changes in 4 cases and soft tissue tumors were seen in 4 cases. Three phase bone scan was more sensitive than delayed whole body bone scan in detecting the abnormal sites (p 0.05) The sensitivity of detecting tumors in blood flow and blood pool phase,delayed phase were respectively lower than in three phase bone scan (p<0.001).Conclusion: It is more sensitivity of detecting tumor lesions in three phase bone scan than in delayed phase whole body bone scan and the changes of blood flow and soft tissue can be seen in three phase bone scan

  17. A simple delay model for two-phase flow dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Clausse, A.; Delmastro, D.F.; Juanico`, L.E. [Centro Atomico Bariloche (Argentina)

    1995-09-01

    A model based in delay equations for density-wave oscillations is presented. High Froude numbers and moderate ones were considered. The equations were numerically analyzed and compared with more sophisticated models. The influence of the gravity term was studied. Different kinds of behavior were found, particularly sub-critical and super-critical Hopf bifurcations. Moreover the present approach can be used to better understand the complicated dynamics of boiling flows systems.

  18. Estimating adolescent sleep need using dose-response modeling.

    Science.gov (United States)

    Short, Michelle A; Weber, Nathan; Reynolds, Chelsea; Coussens, Scott; Carskadon, Mary A

    2018-04-01

    This study will (1) estimate the nightly sleep need of human adolescents, (2) determine the time course and severity of sleep-related deficits when sleep is reduced below this optimal quantity, and (3) determine whether sleep restriction perturbs the circadian system as well as the sleep homeostat. Thirty-four adolescents aged 15 to 17 years spent 10 days and nine nights in the sleep laboratory. Between two baseline nights and two recovery nights with 10 hours' time in bed (TIB) per night, participants experienced either severe sleep restriction (5-hour TIB), moderate sleep restriction (7.5-hour TIB), or no sleep restriction (10-hour TIB) for five nights. A 10-minute psychomotor vigilance task (PVT; lapse = response after 500 ms) and the Karolinska Sleepiness Scale were administered every 3 hours during wake. Salivary dim-light melatonin onset was calculated at baseline and after four nights of each sleep dose to estimate circadian phase. Dose-dependent deficits to sleep duration, circadian phase timing, lapses of attention, and subjective sleepiness occurred. Less TIB resulted in less sleep, more lapses of attention, greater subjective sleepiness, and larger circadian phase delays. Sleep need estimated from 10-hour TIB sleep opportunities was approximately 9 hours, while modeling PVT lapse data suggested that 9.35 hours of sleep is needed to maintain optimal sustained attention performance. Sleep restriction perturbs homeostatic and circadian systems, leading to dose-dependent deficits to sustained attention and sleepiness. Adolescents require more sleep for optimal functioning than typically obtained.

  19. Noise-and delay-induced phase transitions of the dimer–monomer surface reaction model

    International Nuclear Information System (INIS)

    Zeng Chunhua; Wang Hua

    2012-01-01

    Highlights: ► We study the dimer–monomer surface reaction model. ► We show that noise induces first-order irreversible phase transition (IPT). ► Combination of noise and time-delayed feedback induce first- and second-order IPT. ► First- and second-order IPT is viewed as noise-and delay-induced phase transitions. - Abstract: The effects of noise and time-delayed feedback in the dimer–monomer (DM) surface reaction model are investigated. Applying small delay approximation, we construct a stochastic delayed differential equation and its Fokker–Planck equation to describe the state evolution of the DM reaction model. We show that the noise can only induce first-order irreversible phase transition (IPT) characteristic of the DM model, however the combination of the noise and time-delayed feedback can simultaneously induce first- and second-order IPT characteristics of the DM model. Therefore, it is shown that the well-known first- and second-order IPT characteristics of the DM model may be viewed as noise-and delay-induced phase transitions.

  20. ATMOSPHERIC PHASE DELAY CORRECTION OF D-INSAR BASED ON SENTINEL-1A

    Directory of Open Access Journals (Sweden)

    X. Li

    2018-04-01

    Full Text Available In this paper, we used the Generic Atmospheric Correction Online Service for InSAR (GACOS tropospheric delay maps to correct the atmospheric phase delay of the differential interferometric synthetic aperture radar (D-InSAR monitoring, and we improved the accuracy of subsidence monitoring using D-InSAR technology. Atmospheric phase delay, as one of the most important errors that limit the monitoring accuracy of InSAR, would lead to the masking of true phase in subsidence monitoring. For the problem, this paper used the Sentinel-1A images and the tropospheric delay maps got from GACOS to monitor the subsidence of the Yellow River Delta in Shandong Province. The conventional D-InSAR processing was performed using the GAMMA software. The MATLAB codes were used to correct the atmospheric delay of the D-InSAR results. The results before and after the atmospheric phase delay correction were verified and analyzed in the main subsidence area. The experimental results show that atmospheric phase influences the deformation results to a certain extent. After the correction, the measurement error of vertical deformation is reduced by about 18 mm, which proves that the removal of atmospheric effects can improve the accuracy of the D-InSAR monitoring.

  1. Experience-dependent phase-reversal of hippocampal neuron firing during REM sleep.

    Science.gov (United States)

    Poe, G R; Nitz, D A; McNaughton, B L; Barnes, C A

    2000-02-07

    The idea that sleep could serve a cognitive function has remained popular since Freud stated that dreams were "not nonsense" but a time to sort out experiences [S. Freud, Letter to Wilhelm Fliess, May 1897, in The Origins of Psychoanalysis - Personal Letters of Sigmund Freud, M. Bonaparte, A. Freud, E. Kris (Eds.), Translated by E. Mosbacher, J. Strachey, Basic Books and Imago Publishing, 1954]. Rapid eye movement (REM) sleep, which is associated with dream reports, is now known to be is important for acquisition of some tasks [A. Karni, D. Tanne, B.S. Rubenstein, J.J.M. Askenasy, D. Sagi, Dependence on REM sleep of overnight improvement of a perceptual skill, Science 265 (1994) 679-682; C. Smith, Sleep states and learning: a review of the animal literature, Biobehav. Rev. 9 (1985) 157-168]; although why this is so remains obscure. It has been proposed that memories may be consolidated during REM sleep or that forgetting of unnecessary material occurs in this state [F. Crick, G. Mitchison, The function of dream sleep, Nature 304 (1983) 111-114; D. Marr, Simple memory: a theory for archicortex, Philos. Trans. R. Soc. B. 262 (1971) 23-81]. We studied the firing of multiple single neurons in the hippocampus, a structure that is important for episodic memory, during familiar and novel experiences and in subsequent REM sleep. Cells active in familiar places during waking exhibited a reversal of firing phase relative to local theta oscillations in REM sleep. Because firing-phase can influence whether synapses are strengthened or weakened [C. Holscher, R. Anwyl, M.J. Rowan, Stimulation on the positive phase of hippocampal theta rhythm induces long-term potentiation that can be depotentiated by stimulation on the negative phase in area CA1 in vivo, J. Neurosci. 15 (1977) 6470-6477; P.T. Huerta, J.E. Lisman, Bidirectional synaptic plasticity induced by a single burst during cholinergic theta oscillation in CA1 in vitro, Neuron 15 (1995) 1053-1063; C. Pavlides, Y

  2. Termination of short term melatonin treatment in children with delayed Dim Light Melatonin Onset: effects on sleep, health, behavior problems, and parenting stress

    NARCIS (Netherlands)

    van Maanen, Annette; Meijer, Anne Marie; Smits, Marcel G.; Oort, Frans J.

    2011-01-01

    To investigate the effects of termination of short term melatonin treatment on sleep, health, behavior, and parenting stress in children with delayed Dim Light Melatonin Onset. Forty-one children (24 boys, 17 girls; mean age=9.43 years) entered melatonin treatment for 3 weeks and then discontinued

  3. Adjoint method provides phase response functions for delay-induced oscillations.

    Science.gov (United States)

    Kotani, Kiyoshi; Yamaguchi, Ikuhiro; Ogawa, Yutaro; Jimbo, Yasuhiko; Nakao, Hiroya; Ermentrout, G Bard

    2012-07-27

    Limit-cycle oscillations induced by time delay are widely observed in various systems, but a systematic phase-reduction theory for them has yet to be developed. Here we present a practical theoretical framework to calculate the phase response function Z(θ), a fundamental quantity for the theory, of delay-induced limit cycles with infinite-dimensional phase space. We show that Z(θ) can be obtained as a zero eigenfunction of the adjoint equation associated with an appropriate bilinear form for the delay differential equations. We confirm the validity of the proposed framework for two biological oscillators and demonstrate that the derived phase equation predicts intriguing multimodal locking behavior.

  4. ESTIMATION OF PHASE DELAY DUE TO PRECIPITABLE WATER FOR DINSARBASED LAND DEFORMATION MONITORING

    Directory of Open Access Journals (Sweden)

    J. Susaki

    2017-09-01

    Full Text Available In this paper, we present a method for using the estimated precipitable water (PW to mitigate atmospheric phase delay in order to improve the accuracy of land-deformation assessment with differential interferometric synthetic aperture radar (DInSAR. The phase difference obtained from multi-temporal synthetic aperture radar images contains errors of several types, and the atmospheric phase delay can be an obstacle to estimating surface subsidence. In this study, we calculate PW from external meteorological data. Firstly, we interpolate the data with regard to their spatial and temporal resolutions. Then, assuming a range direction between a target pixel and the sensor, we derive the cumulative amount of differential PW at the height of the slant range vector at pixels along that direction. The atmospheric phase delay of each interferogram is acquired by taking a residual after a preliminary determination of the linear deformation velocity and digital elevation model (DEM error, and by applying high-pass temporal and low-pass spatial filters. Next, we estimate a regression model that connects the cumulative amount of PW and the atmospheric phase delay. Finally, we subtract the contribution of the atmospheric phase delay from the phase difference of the interferogram, and determine the linear deformation velocity and DEM error. The experimental results show a consistent relationship between the cumulative amount of differential PW and the atmospheric phase delay. An improvement in land-deformation accuracy is observed at a point at which the deformation is relatively large. Although further investigation is necessary, we conclude at this stage that the proposed approach has the potential to improve the accuracy of the DInSAR technique.

  5. Inter-Individual Differences in Neurobehavioural Impairment following Sleep Restriction Are Associated with Circadian Rhythm Phase

    Science.gov (United States)

    Sletten, Tracey L.; Segal, Ahuva Y.; Flynn-Evans, Erin E.; Lockley, Steven W.; Rajaratnam, Shantha M. W.

    2015-01-01

    Although sleep restriction is associated with decrements in daytime alertness and neurobehavioural performance, there are considerable inter-individual differences in the degree of impairment. This study examined the effects of short-term sleep restriction on neurobehavioural performance and sleepiness, and the associations between individual differences in impairments and circadian rhythm phase. Healthy adults (n = 43; 22 M) aged 22.5 ± 3.1 (mean ± SD) years maintained a regular 8:16 h sleep:wake routine for at least three weeks prior to laboratory admission. Sleep opportunity was restricted to 5 hours time-in-bed at home the night before admission and 3 hours time-in-bed in the laboratory, aligned by wake time. Hourly saliva samples were collected from 5.5 h before until 5 h after the pre-laboratory scheduled bedtime to assess dim light melatonin onset (DLMO) as a marker of circadian phase. Participants completed a 10-min auditory Psychomotor Vigilance Task (PVT), the Karolinska Sleepiness Scale (KSS) and had slow eye movements (SEM) measured by electrooculography two hours after waking. We observed substantial inter-individual variability in neurobehavioural performance, particularly in the number of PVT lapses. Increased PVT lapses (r = -0.468, p circadian phase. When the difference between DLMO and sleep onset was less than 2 hours, individuals were significantly more likely to have at least three attentional lapses the following morning. This study demonstrates that the phase of an individual’s circadian system is an important variable in predicting the degree of neurobehavioural performance impairment in the hours after waking following sleep restriction, and confirms that other factors influencing performance decrements require further investigation. PMID:26043207

  6. Inter-Individual Differences in Neurobehavioural Impairment following Sleep Restriction Are Associated with Circadian Rhythm Phase.

    Directory of Open Access Journals (Sweden)

    Tracey L Sletten

    Full Text Available Although sleep restriction is associated with decrements in daytime alertness and neurobehavioural performance, there are considerable inter-individual differences in the degree of impairment. This study examined the effects of short-term sleep restriction on neurobehavioural performance and sleepiness, and the associations between individual differences in impairments and circadian rhythm phase. Healthy adults (n = 43; 22 M aged 22.5 ± 3.1 (mean ± SD years maintained a regular 8:16 h sleep:wake routine for at least three weeks prior to laboratory admission. Sleep opportunity was restricted to 5 hours time-in-bed at home the night before admission and 3 hours time-in-bed in the laboratory, aligned by wake time. Hourly saliva samples were collected from 5.5 h before until 5 h after the pre-laboratory scheduled bedtime to assess dim light melatonin onset (DLMO as a marker of circadian phase. Participants completed a 10-min auditory Psychomotor Vigilance Task (PVT, the Karolinska Sleepiness Scale (KSS and had slow eye movements (SEM measured by electrooculography two hours after waking. We observed substantial inter-individual variability in neurobehavioural performance, particularly in the number of PVT lapses. Increased PVT lapses (r = -0.468, p < 0.01, greater sleepiness (r = 0.510, p < 0.0001, and more slow eye movements (r = 0.375, p = 0.022 were significantly associated with later DLMO, consistent with participants waking at an earlier circadian phase. When the difference between DLMO and sleep onset was less than 2 hours, individuals were significantly more likely to have at least three attentional lapses the following morning. This study demonstrates that the phase of an individual's circadian system is an important variable in predicting the degree of neurobehavioural performance impairment in the hours after waking following sleep restriction, and confirms that other factors influencing performance decrements require further

  7. Effects of partial time delays on phase synchronization in Watts-Strogatz small-world neuronal networks

    Science.gov (United States)

    Sun, Xiaojuan; Perc, Matjaž; Kurths, Jürgen

    2017-05-01

    In this paper, we study effects of partial time delays on phase synchronization in Watts-Strogatz small-world neuronal networks. Our focus is on the impact of two parameters, namely the time delay τ and the probability of partial time delay pdelay, whereby the latter determines the probability with which a connection between two neurons is delayed. Our research reveals that partial time delays significantly affect phase synchronization in this system. In particular, partial time delays can either enhance or decrease phase synchronization and induce synchronization transitions with changes in the mean firing rate of neurons, as well as induce switching between synchronized neurons with period-1 firing to synchronized neurons with period-2 firing. Moreover, in comparison to a neuronal network where all connections are delayed, we show that small partial time delay probabilities have especially different influences on phase synchronization of neuronal networks.

  8. Security-enhanced chaos communication with time-delay signature suppression and phase encryption.

    Science.gov (United States)

    Xue, Chenpeng; Jiang, Ning; Lv, Yunxin; Wang, Chao; Li, Guilan; Lin, Shuqing; Qiu, Kun

    2016-08-15

    A security-enhanced chaos communication scheme with time delay signature (TDS) suppression and phase-encrypted feedback light is proposed, in virtue of dual-loop feedback with independent high-speed phase modulation. We numerically investigate the property of TDS suppression in the intensity and phase space and quantitatively discuss security of the proposed system by calculating the bit error rate of eavesdroppers who try to crack the system by directly filtering the detected signal or by using a similar semiconductor laser to synchronize the link signal and extract the data. The results show that TDS embedded in the chaotic carrier can be well suppressed by properly setting the modulation frequency, which can keep the time delay a secret from the eavesdropper. Moreover, because the feedback light is encrypted, without the accurate time delay and key, the eavesdropper cannot reconstruct the symmetric operation conditions and decode the correct data.

  9. Evaluating the Coda Phase Delay Method for Determining Temperature Ratios in Windy Environments

    Energy Technology Data Exchange (ETDEWEB)

    Albert, Sarah [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bowman, Daniel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rodgers, Arthur [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Seastrand, Douglas [National Security Technologies, LLC. (NSTec), Las Vegas, NV (United States)

    2017-07-01

    We evaluate the acoustic coda phase delay method for estimating changes in atmospheric phenomena in realistic environments. Previous studies verifying the method took place in an environment with negligible wind. The equation for effective sound speed, which the method is based upon, shows that the influence of wind is equal to the square of temperature. Under normal conditions, wind is significant and therefore cannot be ignored. Results from this study con rm the previous statement. The acoustic coda phase delay method breaks down in non-ideal environments, namely those where wind speed and direction varies across small distances. We suggest that future studies make use of gradiometry to better understand the effect of wind on the acoustic coda and subsequent phase delays.

  10. Sleep and obsessive-compulsive disorder (OCD).

    Science.gov (United States)

    Paterson, Jessica L; Reynolds, Amy C; Ferguson, Sally A; Dawson, Drew

    2013-12-01

    Obsessive-compulsive disorder (OCD) is a chronic mental illness that can have a debilitating effect on daily functioning. A body of research reveals altered sleep behaviour in OCD sufferers; however, findings are inconsistent and there is no consensus on the nature of this relationship. Understanding sleep disturbance in OCD is of critical importance given the known negative consequences of disturbed sleep for mood and emotional wellbeing. A systematic literature search was conducted of five databases for studies assessing sleep in adults diagnosed with OCD. Fourteen studies met inclusion criteria and qualitative data analysis methods were used to identify common themes. There was some evidence of reduced total sleep time and sleep efficiency in OCD patients. Many of the sleep disturbances noted were characteristic of depression. However, some OCD sufferers displayed delayed sleep onset and offset and an increased prevalence of delayed sleep phase disorder (DSPD). Severe OCD symptoms were consistently associated with greater sleep disturbance. While the sleep of OCD patients has not been a major focus to date, the existing literature suggests that addressing sleep disturbance in OCD patients may ensure a holistic approach to treatment, enhance treatment efficacy, mitigate relapse and protect against the onset of co-morbid psychiatric illnesses. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  11. PI and PID controller tuning rule design for processes with delay, to achieve constant gain and phase margins for all values of delay

    OpenAIRE

    O'Dwyer, Aidan

    2001-01-01

    This paper will discuss the design of PI and PID controller tuning rules to compensate processes with delay, that are modelled in a number of ways. The rules allow the achievement of constant gain and phase margins as the delay varies.

  12. Phase of Spontaneous Slow Oscillations during Sleep Influences Memory-Related Processing of Auditory Cues.

    Science.gov (United States)

    Batterink, Laura J; Creery, Jessica D; Paller, Ken A

    2016-01-27

    Slow oscillations during slow-wave sleep (SWS) may facilitate memory consolidation by regulating interactions between hippocampal and cortical networks. Slow oscillations appear as high-amplitude, synchronized EEG activity, corresponding to upstates of neuronal depolarization and downstates of hyperpolarization. Memory reactivations occur spontaneously during SWS, and can also be induced by presenting learning-related cues associated with a prior learning episode during sleep. This technique, targeted memory reactivation (TMR), selectively enhances memory consolidation. Given that memory reactivation is thought to occur preferentially during the slow-oscillation upstate, we hypothesized that TMR stimulation effects would depend on the phase of the slow oscillation. Participants learned arbitrary spatial locations for objects that were each paired with a characteristic sound (eg, cat-meow). Then, during SWS periods of an afternoon nap, one-half of the sounds were presented at low intensity. When object location memory was subsequently tested, recall accuracy was significantly better for those objects cued during sleep. We report here for the first time that this memory benefit was predicted by slow-wave phase at the time of stimulation. For cued objects, location memories were categorized according to amount of forgetting from pre- to post-nap. Conditions of high versus low forgetting corresponded to stimulation timing at different slow-oscillation phases, suggesting that learning-related stimuli were more likely to be processed and trigger memory reactivation when they occurred at the optimal phase of a slow oscillation. These findings provide insight into mechanisms of memory reactivation during sleep, supporting the idea that reactivation is most likely during cortical upstates. Slow-wave sleep (SWS) is characterized by synchronized neural activity alternating between active upstates and quiet downstates. The slow-oscillation upstates are thought to provide a

  13. Time-delay-induced phase-transition to synchrony in coupled bursting neurons

    Science.gov (United States)

    Adhikari, Bhim Mani; Prasad, Awadhesh; Dhamala, Mukeshwar

    2011-06-01

    Signal transmission time delays in a network of nonlinear oscillators are known to be responsible for a variety of interesting dynamic behaviors including phase-flip transitions leading to synchrony or out of synchrony. Here, we uncover that phase-flip transitions are general phenomena and can occur in a network of coupled bursting neurons with a variety of coupling types. The transitions are marked by nonlinear changes in both temporal and phase-space characteristics of the coupled system. We demonstrate these phase-transitions with Hindmarsh-Rose and Leech-Heart interneuron models and discuss the implications of these results in understanding collective dynamics of bursting neurons in the brain.

  14. Phase-coherence transitions and communication in the gamma range between delay-coupled neuronal populations.

    Directory of Open Access Journals (Sweden)

    Alessandro Barardi

    2014-07-01

    Full Text Available Synchronization between neuronal populations plays an important role in information transmission between brain areas. In particular, collective oscillations emerging from the synchronized activity of thousands of neurons can increase the functional connectivity between neural assemblies by coherently coordinating their phases. This synchrony of neuronal activity can take place within a cortical patch or between different cortical regions. While short-range interactions between neurons involve just a few milliseconds, communication through long-range projections between different regions could take up to tens of milliseconds. How these heterogeneous transmission delays affect communication between neuronal populations is not well known. To address this question, we have studied the dynamics of two bidirectionally delayed-coupled neuronal populations using conductance-based spiking models, examining how different synaptic delays give rise to in-phase/anti-phase transitions at particular frequencies within the gamma range, and how this behavior is related to the phase coherence between the two populations at different frequencies. We have used spectral analysis and information theory to quantify the information exchanged between the two networks. For different transmission delays between the two coupled populations, we analyze how the local field potential and multi-unit activity calculated from one population convey information in response to a set of external inputs applied to the other population. The results confirm that zero-lag synchronization maximizes information transmission, although out-of-phase synchronization allows for efficient communication provided the coupling delay, the phase lag between the populations, and the frequency of the oscillations are properly matched.

  15. Effects of Partial and Acute Total Sleep Deprivation on Performance across Cognitive Domains, Individuals and Circadian Phase

    Science.gov (United States)

    Lo, June C.; Groeger, John A.; Santhi, Nayantara; Arbon, Emma L.; Lazar, Alpar S.; Hasan, Sibah; von Schantz, Malcolm; Archer, Simon N.; Dijk, Derk-Jan

    2012-01-01

    Background Cognitive performance deteriorates during extended wakefulness and circadian phase misalignment, and some individuals are more affected than others. Whether performance is affected similarly across cognitive domains, or whether cognitive processes involving Executive Functions are more sensitive to sleep and circadian misalignment than Alertness and Sustained Attention, is a matter of debate. Methodology/Principal Findings We conducted a 2 × 12-day laboratory protocol to characterize the interaction of repeated partial and acute total sleep deprivation and circadian phase on performance across seven cognitive domains in 36 individuals (18 males; mean ± SD of age = 27.6±4.0 years). The sample was stratified for the rs57875989 polymorphism in PER3, which confers cognitive susceptibility to total sleep deprivation. We observed a deterioration of performance during both repeated partial and acute total sleep deprivation. Furthermore, prior partial sleep deprivation led to poorer cognitive performance in a subsequent total sleep deprivation period, but its effect was modulated by circadian phase such that it was virtually absent in the evening wake maintenance zone, and most prominent during early morning hours. A significant effect of PER3 genotype was observed for Subjective Alertness during partial sleep deprivation and on n-back tasks with a high executive load when assessed in the morning hours during total sleep deprivation after partial sleep loss. Overall, however, Subjective Alertness and Sustained Attention were more affected by both partial and total sleep deprivation than other cognitive domains and tasks including n-back tasks of Working Memory, even when implemented with a high executive load. Conclusions/Significance Sleep loss has a primary effect on Sleepiness and Sustained Attention with much smaller effects on challenging Working Memory tasks. These findings have implications for understanding how sleep debt and circadian rhythmicity

  16. Using convolutional decoding to improve time delay and phase estimation in digital communications

    Science.gov (United States)

    Ormesher, Richard C [Albuquerque, NM; Mason, John J [Albuquerque, NM

    2010-01-26

    The time delay and/or phase of a communication signal received by a digital communication receiver can be estimated based on a convolutional decoding operation that the communication receiver performs on the received communication signal. If the original transmitted communication signal has been spread according to a spreading operation, a corresponding despreading operation can be integrated into the convolutional decoding operation.

  17. Effect of Phase Response Curve Skew on Synchronization with and without Conduction Delays

    Directory of Open Access Journals (Sweden)

    Carmen eCanavier

    2013-12-01

    Full Text Available A central problem in cortical processing including sensory binding and attentional gating is how neurons can synchronize their responses with zero or near-zero time lag. For a spontaneously firing neuron, an input from another neuron can delay or advance the next spike by different amounts depending upon the timing of the input relative to the previous spike. This information constitutes the phase response curve (PRC. We present a simple graphical method for determining the effect of PRC shape on synchronization tendencies and illustrate it using type 1 PRCs, which consist entirely of advances (delays in response to excitation (inhibition. We obtained the following generic solutions for type 1 PRCs, which include the pulse coupled leaky integrate and fire model. For pairs with mutual excitation, exact synchrony can be stable for strong coupling because of the stabilizing effect of the causal limit region of the PRC in which an input triggers a spike immediately upon arrival. However, synchrony is unstable for short delays, because delayed inputs arrive during a refractory period and cannot trigger an immediate spike. Right skew destabilizes antiphase and enables modes with time lags that grow as the conduction delay is increased. Therefore, right skew favors near-synchrony at short conduction delays and a gradual transition between synchrony and antiphase for pairs coupled by mutual excitation. For pairs with mutual inhibition, zero time lag synchrony is stable for conduction delays ranging from zero to a substantial fraction of the period for pairs. However, for right skew there is a preferred antiphase mode at short delays. In contrast to mutual excitation, left skew destabilizes antiphase for mutual inhibition so that synchrony dominates at short delays as well. These pairwise synchronization tendencies constrain the synchronization properties of neurons embedded in larger networks.

  18. Staphylococcus aureus Lpl Lipoproteins Delay G2/M Phase Transition in HeLa Cells.

    Science.gov (United States)

    Nguyen, Minh-Thu; Deplanche, Martine; Nega, Mulugeta; Le Loir, Yves; Peisl, Loulou; Götz, Friedrich; Berkova, Nadia

    2016-01-01

    The cell cycle is an ordered set of events, leading to cell growth and division into two daughter cells. The eukaryotic cell cycle consists of interphase (G 1 , S, and G 2 phases), followed by the mitotic phase and G 0 phase. Many bacterial pathogens secrete cyclomodulins that interfere with the host cell cycle. In Staphylococcus aureus four cyclomodulins have been described so far that all represent toxins and are secreted into the culture supernatant. Here we show that the membrane-anchored lipoprotein-like proteins (Lpl), encoded on a genomic island called νSaα, interact with the cell cycle of HeLa cells. By comparing wild type and lpl deletion mutant it turned out that the lpl cluster is causative for the G2/M phase transition delay and also contributes to increased invasion frequency. The lipoprotein Lpl1, a representative of the lpl cluster, also caused G2/M phase transition delay. Interestingly, the lipid modification, which is essential for TLR2 signaling and activation of the immune system, is not necessary for cyclomodulin activity. Unlike the other staphylococcal cyclomodulins Lpl1 shows no cytotoxicity even at high concentrations. As all Lpl proteins are highly conserved there might be a common function that is accentuated by their multiplicity in a tandem gene cluster. The cell surface localized Lpls' suggests a correlation between G2/M phase transition delay and host cell invasion.

  19. Short-term sleep disturbance-induced stress does not affect basal pain perception, but does delay postsurgical pain recovery

    OpenAIRE

    Wang, Po-Kai; Cao, Jing; Wang, Hongzhen; Liang, Lingli; Zhang, Jun; Lutz, Brianna Marie; Shieh, Kun-Ruey; Bekker, Alex; Tao, Yuan-Xiang

    2015-01-01

    Chronic sleep disturbance-induced stress is known to increase basal pain sensitivity. However, most surgical patients frequently report short-term sleep disturbance/deprivation during pre- and post-operation periods and have normal pain perception pre-surgery. Whether this short-term sleep disturbance affects postsurgical pain is elusive. We here reported that pre- or post-exposure to rapid eye movement sleep disturbance (REMSD) 6 h daily for 3 consecutive days did not alter basal responses t...

  20. Genetic Variation in Melatonin Pathway Enzymes in Children with Autism Spectrum Disorder and Comorbid Sleep Onset Delay

    Science.gov (United States)

    Veatch, Olivia J.; Pendergast, Julie S.; Allen, Melissa J.; Leu, Roberta M.; Johnson, Carl Hirschie; Elsea, Sarah H.; Malow, Beth A.

    2015-01-01

    Sleep disruption is common in individuals with autism spectrum disorder (ASD). Genes whose products regulate endogenous melatonin modify sleep patterns and have been implicated in ASD. Genetic factors likely contribute to comorbid expression of sleep disorders in ASD. We studied a clinically unique ASD subgroup, consisting solely of children with…

  1. Delayed Circadian Rhythm in Adults with Attention-Deficit/Hyperactivity Disorder and Chronic Sleep-Onset Insomnia

    NARCIS (Netherlands)

    van Veen, M.M.; Kooij, J.J.S; Boonstra, A. M.; Gordijn, M.C.M.; van Someren, E.J.W.

    2010-01-01

    Background: Previous studies suggest circadian rhythm disturbances in children with attention-deficit/hyperactivity disorder (ADHD) and sleep-onset insomnia (SOI). We investigate here sleep and rhythms in activity and melatonin in adults with ADHD. Methods: Sleep logs and actigraphy data were

  2. Analysis of the effects of time delay in clock recovery circuits based on Phase-locked loops

    DEFF Research Database (Denmark)

    Zibar, Darko; Oxenløwe, Leif Katsuo; Clausen, Anders

    2004-01-01

    Influence of time delay in a balanced optical phase-locked loops (OPLL) with a proportional integrator (Pl) filter is investigated using a delayed differential equation (DDE) is investigated. The limitations, which a time delay imposes on the Pl filter bandwidth, at increasing values of loop gain...

  3. De Novo Truncating Mutations in AHDC1 in Individuals with Syndromic Expressive Language Delay, Hypotonia, and Sleep Apnea

    Science.gov (United States)

    Xia, Fan; Bainbridge, Matthew N.; Tan, Tiong Yang; Wangler, Michael F.; Scheuerle, Angela E.; Zackai, Elaine H.; Harr, Margaret H.; Sutton, V. Reid; Nalam, Roopa L.; Zhu, Wenmiao; Nash, Margot; Ryan, Monique M.; Yaplito-Lee, Joy; Hunter, Jill V.; Deardorff, Matthew A.; Penney, Samantha J.; Beaudet, Arthur L.; Plon, Sharon E.; Boerwinkle, Eric A.; Lupski, James R.; Eng, Christine M.; Muzny, Donna M.; Yang, Yaping; Gibbs, Richard A.

    2014-01-01

    Clinical whole-exome sequencing (WES) for identification of mutations leading to Mendelian disease has been offered to the medical community since 2011. Clinically undiagnosed neurological disorders are the most frequent basis for test referral, and currently, approximately 25% of such cases are diagnosed at the molecular level. To date, there are approximately 4,000 “known” disease-associated loci, and many are associated with striking dysmorphic features, making genotype-phenotype correlations relatively straightforward. A significant fraction of cases, however, lack characteristic dysmorphism or clinical pathognomonic traits and are dependent upon molecular tests for definitive diagnoses. Further, many molecular diagnoses are guided by recent gene-disease association discoveries. Hence, there is a critical interplay between clinical testing and research leading to gene-disease association discovery. Here, we describe four probands, all of whom presented with hypotonia, intellectual disability, global developmental delay, and mildly dysmorphic facial features. Three of the four also had sleep apnea. Each was a simplex case without a remarkable family history. Using WES, we identified AHDC1 de novo truncating mutations that most likely cause this genetic syndrome. PMID:24791903

  4. Delayed Diagnosis, Range of Severity, and Multiple Sleep Comorbidities: A Clinical and Polysomnographic Analysis of 100 Patients of the Innsbruck Narcolepsy Cohort

    Science.gov (United States)

    Frauscher, Birgit; Ehrmann, Laura; Mitterling, Thomas; Gabelia, David; Gschliesser, Viola; Brandauer, Elisabeth; Poewe, Werner; Högl, Birgit

    2013-01-01

    Study Objectives: Narcolepsy is reported to affect 26-56/100,000 in the general population. We aimed to describe clinical and polysomnographic features of a large narcolepsy cohort in order to comprehensively characterize the narcoleptic spectrum. Methods: We performed a chart- and polysomnographybased review of all narcolepsy patients of the Innsbruck narcolepsy cohort. Results: A total of 100 consecutive narcolepsy patients (87 with cataplexy [NC], 13 without cataplexy [N]) were included in the analysis. All subjects had either excessive daytime sleepiness or cataplexy as their initial presenting clinical feature. Age at symptom onset was 20 (6-69) years. Diagnostic delay was 6.5 (0-39) years. The complete narcolepsy tetrad was present in 36/100 patients; 28/100 patients had three cardinal symptoms; 29/100 had two; and 7/100 had only excessive daytime sleepiness. Severity varied broadly with respect to excessive daytime sleepiness (median Epworth Sleepiness Scale score: 18, range 10-24), cataplexy (8-point Likert scale: median 4.5, range 1-8), hypnagogic hallucinations (median 4.5, range 1-7), and sleep paralysis (median 3, range 1-7). Sleep comorbidity was highly prevalent and ranged from sleeprelated movement disorders (n = 55/100), parasomnias (n = 34/100), and sleeprelated breathing disorders (n = 24/100), to insomnia (n = 28/100). REM sleep without atonia or a periodic limb movement in sleep index > 5/h were present in most patients (90/100 and 75/100). A high percentage of narcoleptic patients in the present study had high frequency leg movements (35%) and excessive fragmentary myoclonus (22%). Of the narcolepsy patients with clinical features of REM sleep behavior disorder (RBD), 76.5% had EMG evidence for RBD on the multiple sleep latency test (MSLT), based on a standard cutoff of a minimum of 18% of 3-sec miniepochs. Conclusion: This study is one of the largest monocentric polysomnographic studies to date of patients with narcolepsy and confirms the

  5. Effects of Sleep Deprivation on Phase Synchronization as Assessed by Wavelet Phase Coherence Analysis of Prefrontal Tissue Oxyhemoglobin Signals.

    Science.gov (United States)

    Bu, Lingguo; Zhang, Ming; Li, Jianfeng; Li, Fangyi; Liu, Heshan; Li, Zengyong

    2017-01-01

    To reveal the physiological mechanism of the decline in cognitive function after sleep deprivation, a within-subject study was performed to assess sleep deprivation effects on phase synchronization, as revealed by wavelet phase coherence (WPCO) analysis of prefrontal tissue oxyhemoglobin signals. Twenty subjects (10 male and 10 female, 25.5 ± 3.5 years old) were recruited to participate in two tests: one without sleep deprivation (group A) and the other with 24 h of sleep deprivation (group B). Before the test, each subject underwent a subjective evaluation using visual analog scales. A cognitive task was performed by judging three random numbers. Continuous recordings of the near-infrared spectroscopy (NIRS) signals were obtained from both the left and right prefrontal lobes during rest, task, and post-task periods. The WPCO of cerebral Delta [HbO2] signals were analyzed for these three periods for both groups A and B. Six frequency intervals were defined: I: 0.6-2 Hz (cardiac activity), II: 0.145-0.6 Hz (respiratory activity), III: 0.052-0.145 Hz (myogenic activity), IV: 0.021-0.052 Hz (neurogenic activity), V: 0.0095-0.021 Hz (nitric oxide related endothelial activity) and VI: 0.005-0.0095 Hz (non-nitric oxide related endothelial activity). WPCO in intervals III (F = 5.955, p = 0.02) and V (F = 4.7, p = 0.037) was significantly lower in group B than in group A at rest. During the task period, WPCO in intervals III (F = 5.175, p = 0.029) and IV (F = 4.585, p = 0.039) was significantly lower in group B compared with group A. In the post-task recovery period, the WPCO in interval III (F = 6.125, p = 0.02) was significantly lower in group B compared with group A. Reaction time was significantly prolonged, and the accuracy rate and F1 score both declined after sleep deprivation. The decline in WPCO after sleep deprivation indicates reduced phase synchronization between left and right prefrontal oxyhemoglobin oscillations, which may contribute to the diminished

  6. Arbitrary-step randomly delayed robust filter with application to boost phase tracking

    Science.gov (United States)

    Qin, Wutao; Wang, Xiaogang; Bai, Yuliang; Cui, Naigang

    2018-04-01

    The conventional filters such as extended Kalman filter, unscented Kalman filter and cubature Kalman filter assume that the measurement is available in real-time and the measurement noise is Gaussian white noise. But in practice, both two assumptions are invalid. To solve this problem, a novel algorithm is proposed by taking the following four steps. At first, the measurement model is modified by the Bernoulli random variables to describe the random delay. Then, the expression of predicted measurement and covariance are reformulated, which could get rid of the restriction that the maximum number of delay must be one or two and the assumption that probabilities of Bernoulli random variables taking the value one are equal. Next, the arbitrary-step randomly delayed high-degree cubature Kalman filter is derived based on the 5th-degree spherical-radial rule and the reformulated expressions. Finally, the arbitrary-step randomly delayed high-degree cubature Kalman filter is modified to the arbitrary-step randomly delayed high-degree cubature Huber-based filter based on the Huber technique, which is essentially an M-estimator. Therefore, the proposed filter is not only robust to the randomly delayed measurements, but robust to the glint noise. The application to the boost phase tracking example demonstrate the superiority of the proposed algorithms.

  7. Delayed-Start Analyses in the Phase 3 Solanezumab EXPEDITION3 Study in Mild Alzheimer's Disease.

    Science.gov (United States)

    Liu-Seifert, H; Case, M G; Andersen, S W; Holdridge, K C; Aisen, P S; Kollack-Walker, S; Siemers, E

    2018-01-01

    A delayed-start design has been proposed to assess a potential disease-modifying effect in investigational drugs for Alzheimer's disease that target the underlying disease process. We extended this methodology to recently obtained data from the EXPEDITION3. EXPEDITION3 was a Phase 3, double-blind study with participants randomized to solanezumab (400 mg) or placebo every 4 weeks for 80 weeks, with an optional extension of active treatment. The delayed-start analysis was designed to determine if a statistically significant treatment difference established during the placebo-controlled period is maintained (at predefined level) during the delayed-start period, which would suggest the active drug has a disease-modifying effect. The delayed-start analysis was assessed across multiple efficacy measures, and includes data from baseline in the placebo-controlled period and up to 9 months in the delayed-start period. No significant difference was observed between the placebo and solanezumab treatment groups at the end of the placebo-controlled period for the Alzheimer's Disease Assessment Scale-Cognitive 14-item subscale. A significant treatment difference was observed at the end of the placebo-controlled period for the Alzheimer's Disease Cooperative Study-Activities of Daily Living instrumental items, an effect also seen at 6 months in the delayed-start period, and the noninferiority criterion was met. No other efficacy measures met these criteria. Delayed-start statistical methodology was used to understand the longitudinal outcomes in EXPEDITION3 and its extension. The small treatment differences observed at the end of the placebo-controlled phase prevented adequate assessment of any putative disease modifying effect.

  8. An hour of bright white light in the early morning improves performance and advances sleep and circadian phase during the Antarctic winter.

    Science.gov (United States)

    Corbett, R W; Middleton, B; Arendt, J

    2012-09-13

    Previous work has demonstrated that exposure to an hour of bright light in the morning and the evening during the Polar winter has beneficial effects on circadian phase. This study investigated the effect of a single hour of bright white morning light on circadian phase, sleep, alertness and cognitive performance. Nine individuals (eight male, one female, median age 30 years), wintering at Halley Research Station (75°S), Antarctica from 7th May until 6th August 2007, were exposed to bright white light for a fortnight from 08:30 to 09:30 h, with two fortnight control periods on either side. This sequence was performed twice, before and following Midwinter. Light exposure, sleep and alertness were assessed daily by actigraphy, sleep diaries and subjective visual analogue scales. Circadian phase (assessed by urinary 6-sulphatoxymelatonin rhythm) and cognitive performance were evaluated at the end of each fortnight. During light exposure circadian phase was advanced from 4.97 ± 0.96 decimal hours (dh) (mean ± SD) to 4.08 ± 0.68 dh (p = 0.003). Wake-up time was shifted by a similar margin from 8.45 ± 1.83 dh to 7.59 ± 0.78 dh (p < 0.001). Sleep start time was also advanced (p = 0.047) but by a lesser amount, consequently, actual sleep time was slightly reduced. There was no change in objective or subjective measures of sleep quality or subjective measures of alertness. An improvement in cognitive performance was found with both the Single Letter Cancellation Test (p < 0.001) and the Digit Symbol Substitution Test (p = 0.026) with preserved circadian variation. These beneficial effects of a single short duration light treatment may have implications not only for the Antarctic but other remote environments where access to natural light and delayed circadian phase, is problematic. These results require validation in larger studies at varying locations. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  9. [How to characterize and treat sleep complaints in bipolar disorders?

    Science.gov (United States)

    Geoffroy, P A; Micoulaud Franchi, J-A; Lopez, R; Poirot, I; Brion, A; Royant-Parola, S; Etain, B

    2017-08-01

    Sleep complaints are very common in bipolar disorders (BD) both during acute phases (manic and depressive episodes) and remission (about 80 % of patients with remitted BD have poor sleep quality). Sleep complaints during remission are of particular importance since they are associated with more mood relapses and worse outcomes. In this context, this review discusses the characterization and treatment of sleep complaints in BD. We examined the international scientific literature in June 2016 and performed a literature search with PubMed electronic database using the following headings: "bipolar disorder" and ("sleep" or "insomnia" or "hypersomnia" or "circadian" or "apnoea" or "apnea" or "restless legs"). Patients with BD suffer from sleep and circadian rhythm abnormalities during major depressive episodes (insomnia or hypersomnia, nightmares, nocturnal and/or early awakenings, non-restorative sleep) and manic episodes (insomnia, decreased need for sleep without fatigue), but also some of these abnormalities may persist during remission. These remission phases are characterized by a reduced quality and quantity of sleep, with a longer sleep duration, increased sleep latency, a lengthening of the wake time after sleep onset (WASO), a decrease of sleep efficiency, and greater variability in sleep/wake rhythms. Patients also present frequent sleep comorbidities: chronic insomnia, sleepiness, sleep phase delay syndrome, obstructive sleep apnea/hypopnea syndrome (OSAHS), and restless legs syndrome (RLS). These disorders are insufficiently diagnosed and treated whereas they are associated with mood relapses, treatment resistance, affect cognitive global functioning, reduce the quality of life, and contribute to weight gain or metabolic syndrome. Sleep and circadian rhythm abnormalities have been also associated with suicidal behaviors. Therefore, a clinical exploration with characterization of these abnormalities and disorders is essential. This exploration should be

  10. Exploitation of Digital Filters to Advance the Single-Phase T/4 Delay PLL System

    DEFF Research Database (Denmark)

    Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede

    2016-01-01

    will violate this design rule and it can become a major challenge for digital controllers. To deal with the above issue, this paper first exploits a virtual unit delay (z_v^-1) to emulate the viable sampling behavior in practical digital signal processors with a fixed sampling rate. This exploitation......With the development of digital signal processing technologies, control and monitoring of power electronics conversion systems have been evolving to become fully digital. As the basic element in the design and analysis phase of digital controllers or filters, a number of unit delays (z^-1) have...... been employed, e.g., in a cascaded structure. Practically, the number of unit delays is designed as an integer, which is related to the sampling frequency (e.g., 50 Hz). More common, the sampling frequency is fixed during operation for simplicity and design. Hence, any disturbance in the ac signal...

  11. The relationship of luteinizing hormone secretion to sleep in women during the early follicular phase: effects of sleep reversal and a prolonged three-hour sleep-wake schedule.

    Science.gov (United States)

    Kapen, S; Boyar, R; Hellman, L; Weitzman, E D

    1976-06-01

    The relationship of luteinizing hormone (LH) secretion to sleep in adult women was investigated in two ways: an acute 180 degrees sleep-wake cycle reversal in a group of six women and a schedule in which a young woman engaged in a three hour sleep-wake cycle (two hours awake, one hour allowed for sleep continuously for ten days--the study was carried out on the eighth day). Each subject in the reversal study had a baseline period during which plasma samples were collected every twenty minutes for twenty-four hours and nocturnal sleep was monitored electrophysiologically during the early follicular phase of the menstrual cycle. During a succeeding cycle, the study was repeated after sleep-wake reversal. LH secretory patterns were analyzed by comparing the 24-hour mean plasma LH concentration with the hourly averages in percentage terms, using Stage 2 sleep onset as the zero point. LH secretion was depressed to approximately the same degree in both the baseline and reversal studies. The average hourly percentage difference from the 24-hour mean for the four-hour period following sleep onset was -13.4% and -13.1% for the baseline and reversal, respectively. These percentage deviations represented practically the entire negative deviation for the 24-hour period in both studies. The difference between the first four-hour period after sleep onset and the second was significant. The subject on a three-hour cycle had a baseline in which a large decrease in LH secretion occurred after sleep onset (-52.2% during the third hour). Her LH secretory pattern during the three-hour sleep-wake schedule was characterized by a fall during sleep periods, particularly when slow wave sleep (SWS) predominated. However, no correlation was found between specific sleep stages and LH secretion in the six women of the reversal study. These results confirm a relationship of LH secretion to sleep in adult women, one which is different from that described during puberty.

  12. Comparison of coherence and phase synchronization of the human sleep electroencephalogram

    Czech Academy of Sciences Publication Activity Database

    Mezeiová, K.; Paluš, Milan

    2012-01-01

    Roč. 123, č. 9 (2012), s. 1821-1830 ISSN 1388-2457 R&D Projects: GA MŠk 7E08027 EU Projects: European Commission(XE) 200728 - BRAINSYNC Grant - others:AV ČR - SAS(CZ-SK) Modern Methods for Analysis of Electrophysiological Signals Institutional research plan: CEZ:AV0Z10300504 Keywords : phase synchronization * complete synchronization * mean phase coherence * permutation surrogate data * coherence * human sleep EEG Subject RIV: FH - Neurology Impact factor: 3.144, year: 2012

  13. The WS transform for the Kuramoto model with distributed amplitudes, phase lag and time delay

    Science.gov (United States)

    Lohe, M. A.

    2017-12-01

    We apply the Watanabe-Strogatz (WS) transform to a generalized Kuramoto model with distributed parameters describing the amplitude of oscillation, phase lag, and time delay at each node of the system. The model has global coupling and identical frequencies, but allows for repulsive interactions at arbitrary nodes leading to conformist-contrarian phenomena together with variable amplitude and time-delay effects. We show how to determine the initial values of the WS system for any initial conditions for the Kuramoto system, and investigate the asymptotic behaviour of the WS variables. For the case of zero time delay the possible asymptotic configurations are determined by the sign of a single parameter μ which measures whether or not the attractive nodes dominate the repulsive nodes. If μ>0 the system completely synchronizes from general initial conditions, whereas if μ<0 one of two types of phase-locked synchronization occurs, depending on the initial values, while for μ=0 periodic solutions can occur. For the case of arbitrary non-uniform time delays we derive a stability condition for completely synchronized solutions.

  14. Implementation of High Time Delay Accuracy of Ultrasonic Phased Array Based on Interpolation CIC Filter.

    Science.gov (United States)

    Liu, Peilu; Li, Xinghua; Li, Haopeng; Su, Zhikun; Zhang, Hongxu

    2017-10-12

    In order to improve the accuracy of ultrasonic phased array focusing time delay, analyzing the original interpolation Cascade-Integrator-Comb (CIC) filter, an 8× interpolation CIC filter parallel algorithm was proposed, so that interpolation and multichannel decomposition can simultaneously process. Moreover, we summarized the general formula of arbitrary multiple interpolation CIC filter parallel algorithm and established an ultrasonic phased array focusing time delay system based on 8× interpolation CIC filter parallel algorithm. Improving the algorithmic structure, 12.5% of addition and 29.2% of multiplication was reduced, meanwhile the speed of computation is still very fast. Considering the existing problems of the CIC filter, we compensated the CIC filter; the compensated CIC filter's pass band is flatter, the transition band becomes steep, and the stop band attenuation increases. Finally, we verified the feasibility of this algorithm on Field Programming Gate Array (FPGA). In the case of system clock is 125 MHz, after 8× interpolation filtering and decomposition, time delay accuracy of the defect echo becomes 1 ns. Simulation and experimental results both show that the algorithm we proposed has strong feasibility. Because of the fast calculation, small computational amount and high resolution, this algorithm is especially suitable for applications with high time delay accuracy and fast detection.

  15. Implementation of High Time Delay Accuracy of Ultrasonic Phased Array Based on Interpolation CIC Filter

    Directory of Open Access Journals (Sweden)

    Peilu Liu

    2017-10-01

    Full Text Available In order to improve the accuracy of ultrasonic phased array focusing time delay, analyzing the original interpolation Cascade-Integrator-Comb (CIC filter, an 8× interpolation CIC filter parallel algorithm was proposed, so that interpolation and multichannel decomposition can simultaneously process. Moreover, we summarized the general formula of arbitrary multiple interpolation CIC filter parallel algorithm and established an ultrasonic phased array focusing time delay system based on 8× interpolation CIC filter parallel algorithm. Improving the algorithmic structure, 12.5% of addition and 29.2% of multiplication was reduced, meanwhile the speed of computation is still very fast. Considering the existing problems of the CIC filter, we compensated the CIC filter; the compensated CIC filter’s pass band is flatter, the transition band becomes steep, and the stop band attenuation increases. Finally, we verified the feasibility of this algorithm on Field Programming Gate Array (FPGA. In the case of system clock is 125 MHz, after 8× interpolation filtering and decomposition, time delay accuracy of the defect echo becomes 1 ns. Simulation and experimental results both show that the algorithm we proposed has strong feasibility. Because of the fast calculation, small computational amount and high resolution, this algorithm is especially suitable for applications with high time delay accuracy and fast detection.

  16. Estimating dim light melatonin onset (DLMO) phase in adolescents using summer or school-year sleep/wake schedules.

    Science.gov (United States)

    Crowley, Stephanie J; Acebo, Christine; Fallone, Gahan; Carskadon, Mary A

    2006-12-01

    This analysis examined associations between the salivary dim light melatonin onset (DLMO) phase and self-selected sleep/ wake schedules in groups of children and adolescents during summer vacation and during the school year to determine the degree to which sleep/wake patterns can estimate salivary DLMO phase. Participants slept at home on self-selected schedules for 5 consecutive nights and reported their bedtime and wake-up time via daily telephone messages. Salivary melatonin was sampled in the laboratory on one evening every 30 minutes in dim light (females) contributed 149 DLMO phase and sleep/wake pattern measures while on a school year schedule ("school group"). A separate group, ages 9 to 16 years (mean age = 13.1, SD = 1.3 years, 30 males, 29 females) contributed 59 DLMO phase and sleep/wake pattern measures while on a summer schedule ("summer group"). Bedtime, midsleep time, and wake-up time were positively correlated with DLMO phase in both groups. Although all correlation coefficients for the summer group were statistically greater compared to the school group, the regression equations predicted DLMO phase within +/- 1 hour of the measured DLMO phase in approximately 80% for both groups. DLMO phase can be estimated using self-selected sleep/wake patterns during the school year or summer vacation in healthy children and adolescents.

  17. Pulse Compression of Phase-matched High Harmonic Pulses from a Time-Delay Compensated Monochromator

    Directory of Open Access Journals (Sweden)

    Ito Motohiko

    2013-03-01

    Full Text Available Pulse compression of single 32.6-eV high harmonic pulses from a time-delay compensated monochromator was demonstrated down to 11±3 fs by compensating the pulse front tilt. The photon flux was intensified up to 5.7×109 photons/s on target by implementing high harmonic generation under a phase matching condition in a hollow fiber used for increasing the interaction length.

  18. Phase-Shift Cyclic-Delay Diversity for MIMO OFDM Systems

    Directory of Open Access Journals (Sweden)

    Young-Han Nam

    2010-01-01

    Full Text Available Phase-shift cyclic-delay diversity (PS CDD scheme and space-frequency-block-code (SFBC PS CDD are developed for multiple-input-multiple-output (MIMO orthogonal frequency division multiplexing (OFDM systems. The proposed PS CDD scheme preserves the diversity advantage of traditional CDD in uncorrelated multiantenna channels, and furthermore removes frequency-selective nulling problem of the traditional CDD in correlated multiantenna channels.

  19. Forced phase-locked response of a nonlinear system with time delay after Hopf bifurcation

    International Nuclear Information System (INIS)

    Ji, J.C.; Hansen, Colin H.

    2005-01-01

    The trivial equilibrium of a nonlinear autonomous system with time delay may become unstable via a Hopf bifurcation of multiplicity two, as the time delay reaches a critical value. This loss of stability of the equilibrium is associated with two coincident pairs of complex conjugate eigenvalues crossing the imaginary axis. The resultant dynamic behaviour of the corresponding nonlinear non-autonomous system in the neighbourhood of the Hopf bifurcation is investigated based on the reduction of the infinite-dimensional problem to a four-dimensional centre manifold. As a result of the interaction between the Hopf bifurcating periodic solutions and the external periodic excitation, a primary resonance can occur in the forced response of the system when the forcing frequency is close to the Hopf bifurcating periodic frequency. The method of multiple scales is used to obtain four first-order ordinary differential equations that determine the amplitudes and phases of the phase-locked periodic solutions. The first-order approximations of the periodic solutions are found to be in excellent agreement with those obtained by direct numerical integration of the delay-differential equation. It is also found that the steady state solutions of the nonlinear non-autonomous system may lose their stability via either a pitchfork or Hopf bifurcation. It is shown that the primary resonance response may exhibit symmetric and asymmetric phase-locked periodic motions, quasi-periodic motions, chaotic motions, and coexistence of two stable motions

  20. Evening daylight may cause adolescents to sleep less in spring than in winter

    Science.gov (United States)

    Figueiro, Mariana G.; Rea, Mark S.

    2012-01-01

    Sleep restriction commonly experienced by adolescents can stem from greater sleep pressure by the homeostatic processes and from phase delays of the circadian system. With regard to the latter potential cause, we hypothesized that because there is more natural evening light during the spring than winter, a sample of adolescent students would be more phase delayed in spring than in winter, would have later sleep onset times and, because of fixed school schedules, would have shorter sleep durations. Sixteen eighth-grade subjects were recruited for the study. We collected sleep logs and saliva samples to determine their dim light melatonin onset (DLMO), a well-established circadian marker. Actual circadian light exposures experienced by a subset of twelve subjects over the course of seven days in winter and in spring using a personal, head-worn, circadian light measurement device are also reported here. Results showed that this sample of adolescents was exposed to significantly more circadian light in spring than in winter, especially in the evening hours when light exposure would likely delay circadian phase. Consistent with the light data, DLMO and sleep onset times were significantly more delayed, and sleep durations were significantly shorter in spring than in winter. The present ecological study of light, circadian phase, and self-reported sleep suggests that greater access to evening daylight in the spring may lead to sleep restriction in adolescents while attending school. Therefore, lighting schemes that reduce evening light in the spring may encourage longer sleep times in adolescents. PMID:20653452

  1. Association between sleep stages and hunger scores in 36 children.

    Science.gov (United States)

    Arun, R; Pina, P; Rubin, D; Erichsen, D

    2016-10-01

    Childhood obesity is a growing health challenge. Recent studies show that children with late bedtime and late awakening are more obese independent of total sleep time. In adolescents and adults, a delayed sleep phase has been associated with higher caloric intake. Furthermore, an adult study showed a positive correlation between REM sleep and energy balance. This relationship has not been demonstrated in children. However, it may be important as a delayed sleep phase would increase the proportion of REM sleep. This study investigated the relationship between hunger score and sleep physiology in a paediatric population. Thirty-six patients referred for a polysomnogram for suspected obstructive sleep apnoea were enrolled in the study. Sleep stages were recorded as part of the polysomnogram. Hunger scores were obtained using a visual analogue scale. Mean age was 9.6 ± 3.5 years. Mean hunger scores were 2.07 ± 2.78. Hunger scores were positively correlated with percentage of total rapid eye movement (REM) sleep (r = 0.438, P hunger score (r = -0.360, P hunger scores. These findings suggest that delayed bedtime, which increases the proportion of REM sleep and decreases the proportion of SWS, results in higher hunger levels in children. © 2015 World Obesity.

  2. Phase advancing human circadian rhythms with morning bright light, afternoon melatonin, and gradually shifted sleep: can we reduce morning bright-light duration?

    Science.gov (United States)

    Crowley, Stephanie J; Eastman, Charmane I

    2015-02-01

    Efficient treatments to phase-advance human circadian rhythms are needed to attenuate circadian misalignment and the associated negative health outcomes that accompany early-morning shift work, early school start times, jet lag, and delayed sleep phase disorder. This study compared three morning bright-light exposure patterns from a single light box (to mimic home treatment) in combination with afternoon melatonin. Fifty adults (27 males) aged 25.9 ± 5.1 years participated. Sleep/dark was advanced 1 h/day for three treatment days. Participants took 0.5 mg of melatonin 5 h before the baseline bedtime on treatment day 1, and an hour earlier each treatment day. They were exposed to one of three bright-light (~5000 lux) patterns upon waking each morning: four 30-min exposures separated by 30 min of room light (2-h group), four 15-min exposures separated by 45 min of room light (1-h group), and one 30-min exposure (0.5-h group). Dim-light melatonin onsets (DLMOs) before and after treatment determined the phase advance. Compared to the 2-h group (phase shift = 2.4 ± 0.8 h), smaller phase-advance shifts were seen in the 1-h (1.7 ± 0.7 h) and 0.5-h (1.8 ± 0.8 h) groups. The 2-h pattern produced the largest phase advance; however, the single 30-min bright-light exposure was as effective as 1 h of bright light spread over 3.25 h, and it produced 75% of the phase shift observed with 2 h of bright light. A 30-min morning bright-light exposure with afternoon melatonin is an efficient treatment to phase-advance human circadian rhythms. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Phase advancing human circadian rhythms with morning bright light, afternoon melatonin, and gradually shifted sleep: can we reduce morning bright light duration?

    Science.gov (United States)

    Crowley, Stephanie J.; Eastman, Charmane I.

    2015-01-01

    OBJECTIVE Efficient treatments to phase advance human circadian rhythms are needed to attenuate circadian misalignment and the associated negative health outcomes that accompany early morning shift work, early school start times, jet lag, and delayed sleep phase disorder. This study compared three morning bright light exposure patterns from a single light box (to mimic home treatment) in combination with afternoon melatonin. METHODS Fifty adults (27 males) aged 25.9±5.1 years participated. Sleep/dark was advanced 1 hour/day for 3 treatment days. Participants took 0.5 mg melatonin 5 hours before baseline bedtime on treatment day 1, and an hour earlier each treatment day. They were exposed to one of three bright light (~5000 lux) patterns upon waking each morning: four 30-minute exposures separated by 30 minutes of room light (2 h group); four 15-minute exposures separated by 45 minutes of room light (1 h group), and one 30-minute exposure (0.5 h group). Dim light melatonin onsets (DLMOs) before and after treatment determined the phase advance. RESULTS Compared to the 2 h group (phase shift=2.4±0.8 h), smaller phase advance shifts were seen in the 1 h (1.7±0.7 h) and 0.5 h (1.8±0.8 h) groups. The 2-hour pattern produced the largest phase advance; however, the single 30-minute bright light exposure was as effective as 1 hour of bright light spread over 3.25 h, and produced 75% of the phase shift observed with 2 hours of bright light. CONCLUSIONS A 30-minute morning bright light exposure with afternoon melatonin is an efficient treatment to phase advance human circadian rhythms. PMID:25620199

  4. Cortico-pontine theta carrier frequency phase shift across sleep/wake states following monoaminergic lesion in rat.

    Science.gov (United States)

    Kalauzi, Aleksandar; Spasic, Sladjana; Petrovic, Jelena; Ciric, Jelena; Saponjic, Jelena

    2012-06-01

    This study was aimed to explore the sleep/wake states related cortico-pontine theta carrier frequency phase shift following a systemically induced chemical axotomy of the monoaminergic afferents within a brain of the freely moving rats. Our experiments were performed in 14 adult, male Sprague Dawley rats, chronically implanted for sleep recording. We recorded sleep during baseline condition, following sham injection (saline i.p. 1 ml/kg), and every week for 5 weeks following injection of the systemic neurotoxins (DSP-4 or PCA; 1 ml/kg, i.p.) for chemical axotomy of the locus coeruleus (LC) and dorsal raphe (DR) axon terminals. After sleep/wake states identification, FFT analysis was performed on 5 s epochs. Theta carrier frequency phase shift (∆Φ) was calculated for each epoch by averaging theta Fourier component phase shifts, and the ∆Φ values were plotted for each rat in control condition and 28 days following the monoaminergic lesions, as a time for permanently established DR or LC chemical axotomy. Calculated group averages have shown that ∆Φ increased between pons and cortex significantly in all sleep/wake states (Wake, NREM and REM) following the monoaminergic lesions, with respect to controls. Monoaminergic lesions established the pontine leading role in the brain theta oscillations during all sleep/wake states.

  5. Identifying and comparing states of time-delayed systems: phase diagrams and applications to human motor control systems

    International Nuclear Information System (INIS)

    Frank, T.D.; Friedrich, R.; Beek, P.J.

    2005-01-01

    A data driven characterization of time-delayed stochastic systems is proposed in terms of linear delay differential equations and two drift parameters. It is shown how these parameters determine the states of such systems with respect to generalized phase diagrams. This approach allows for a comparison of systems with different parameters as exemplified for two motor control tasks: tracking and force production

  6. Repeated exposure to conditioned fear stress increases anxiety and delays sleep recovery following exposure to an acute traumatic stressor

    Directory of Open Access Journals (Sweden)

    Benjamin N Greenwood

    2014-10-01

    Full Text Available Repeated stressor exposure can sensitize physiological responses to novel stressors and facilitate the development of stress-related psychiatric disorders including anxiety. Disruptions in diurnal rhythms of sleep-wake behavior accompany stress-related psychiatric disorders and could contribute to their development. Complex stressors that include fear-eliciting stimuli can be a component of repeated stress experienced by humans, but whether exposure to repeated fear can prime the development of anxiety and sleep disturbances is unknown. In the current study, adult male F344 rats were exposed to either control conditions or repeated contextual fear conditioning for 22 days followed by exposure to either no, mild (10, or severe (100 acute uncontrollable tail shock stress. Exposure to acute stress produced anxiety-like behavior as measured by a reduction in juvenile social exploration and exaggerated shock-elicited freezing in a novel context. Prior exposure to repeated fear enhanced anxiety-like behavior as measured by shock-elicited freezing, but did not alter social exploratory behavior. The potentiation of anxiety produced by prior repeated fear was temporary; exaggerated fear was present 1 day but not 4 days following acute stress. Interestingly, exposure to acute stress reduced REM and NREM sleep during the hours immediately following acute stress. This initial reduction in sleep was followed by robust REM rebound and diurnal rhythm flattening of sleep / wake behavior. Prior repeated fear extended the acute stress-induced REM and NREM sleep loss, impaired REM rebound, and prolonged the flattening of the diurnal rhythm of NREM sleep following acute stressor exposure. These data suggest that impaired recovery of sleep / wake behavior following acute stress could contribute to the mechanisms by which a history of prior repeated stress increases vulnerability to subsequent novel stressors and stress-related disorders.

  7. Nuclear medicine methods in the field of studying the mechanisms of delayed phase of myocardial preconditioning

    International Nuclear Information System (INIS)

    Wang Shuxia

    2001-01-01

    Ischemic preconditioning is the intrinsic and most potently myocardial protection. Its mechanism is the foundation of rational therapeutic application. Nowadays there are some theories about delayed phase of preconditioning such as nitric oxide hypothesis, free radical mechanisms, protective protein synthesis and opening of ATP-sensitive potassium channels. By incorporation 3 H-leucine, using liquid scintillation counter, the authors know there was protective protein synthesis during preconditioning. SPECT could study the characteristics of preconditioned myocardium in vivo, and PET might further show the metabolism, energy consumption and its relationship to myocardium dysfunction

  8. Sleep-Wake Patterns during the Acute Phase after First-Ever Stroke

    Directory of Open Access Journals (Sweden)

    Linda N. Bakken

    2011-01-01

    Full Text Available This study describes the pattern of day and night sleep and explores relationships between these patterns and sociodemographic and clinical factors as well as sleep environmental context and the patient's subjective sleep quality. Data from 110 patients with first-ever stroke was collected by structured interview surveys, medical record, and objective estimated sleep data from wrist actigraphy. The variability in estimated sleep is large. Half the patients slept either 8 hours per night, and 78% had more than nine awakenings per night. Men slept less than women, and patients sleeping at home had fewer awakenings than those who slept in hospital. It was estimated sleep during daytime in all, except 4, patients. Longer stay in hospital was related to more daytime sleep, and the subjective sleep quality correlated with estimated sleep time, wake time, and wake percentage.

  9. Delay equations modeling the effects of phase-specific drugs and immunotherapy on proliferating tumor cells.

    Science.gov (United States)

    Barbarossa, Maria Vittoria; Kuttler, Christina; Zinsl, Jonathan

    2012-04-01

    In this work we present a mathematical model for tumor growth based on the biology of the cell cycle. For an appropriate description of the effects of phase-specific drugs, it is necessary to look at the cell cycle and its phases. Our model reproduces the dynamics of three different tumor cell populations: quiescent cells, cells during the interphase and mitotic cells. Starting from a partial differential equations (PDEs) setting, a delay differential equations (DDE) model is derived for an easier and more realistic approach. Our equations also include interactions of tumor cells with immune system effectors. We investigate the model both from the analytical and the numerical point of view, give conditions for positivity of solutions and focus on the stability of the cancer-free equilibrium. Different immunotherapeutic strategies and their effects on the tumor growth are considered, as well.

  10. National data showed that delayed sleep in six-year-old children was associated with excessive use of electronic devices at 12 years.

    Science.gov (United States)

    Kato, Tsuguhiko; Yorifuji, Takashi; Yamakawa, Michiyo; Inoue, Sachiko

    2018-01-31

    Cross-sectional studies have shown associations between adolescent sleep problems and the use of electronic devices, such as mobile phones, but longitudinal studies remain scarce. We explored any association between delayed bedtimes at six years old and the excessive use of electronic devices at 12 years of age. Texting was a prime focus. We analysed 9607 adolescents who owned mobile phones in 2013 using the Japanese Longitudinal Survey of Newborns in the 21st Century, which started in 2001. The outcomes were daily excessive use of a mobile phone, television (TV) and video games. Delayed bedtime at the age of six years was associated with excessive texting at weekends. The adjusted odds ratios and 95% confidence intervals obtained from logistic regression analyses were 1.88 (1.14-3.10) for the 10-11 pm group and 1.98 (1.08-3.63) for the after 11 pm group, compared with the before 9 pm group. Later bedtimes were also associated with increased risks of excessive TV viewing and video game use. Our study indicated that six-year-olds who regularly stayed up late at night used electronic devices more frequently, or for longer, at the age of 12. Parents need to be more aware of links between sleep issues and electronic devices. ©2018 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

  11. Dopamine agonist suppression of rapid-eye-movement sleep is secondary to sleep suppression mediated via limbic structures

    International Nuclear Information System (INIS)

    Miletich, R.S.

    1985-01-01

    The effects of pergolide, a direct dopamine receptor agonist, on sleep and wakefulness, motor behavior and 3 H-spiperone specific binding in limbic structures and striatum in rats was studied. The results show that pergolide induced a biphasic dose effect, with high doses increasing wakefulness and suppressing sleep while low dose decreased wakefulness, but increased sleep. It was shown that pergolide-induced sleep suppression was blocked by α-glupenthixol and pimozide, two dopamine receptor antagonists. It was further shown that pergolide merely delayed the rebound resulting from rapid-eye-movement (REM) sleep deprivation, that dopamine receptors stimulation had no direct effect on the period, phase or amplitude of the circadian rhythm of REM sleep propensity and that there was no alteration in the coupling of REM sleep episodes with S 2 episodes. Rapid-eye-movement sleep deprivation resulted in increased sensitivity to the pergolide-induced wakefulness stimulation and sleep suppression and pergolide-induced motor behaviors of locomotion and head bobbing. 3 H-spiperone specific binding to dopamine receptors was shown to be altered by REM sleep deprivation in the subcortical limbic structures. It is concluded that the REM sleep suppressing action of dopamine receptor stimulation is secondary to sleep suppression per se and not secondary to a unique effect on the REM sleep. Further, it is suggested that the wakefulness stimulating action of dopamine receptor agonists is mediated by activation of the dopamine receptors in the terminal areas of the mesolimbocortical dopamine projection system

  12. Sleep-wake patterns and sleep disturbance among Hong Kong Chinese adolescents.

    Science.gov (United States)

    Chung, Ka-Fai; Cheung, Miao-Miao

    2008-02-01

    To determine sleep-wake patterns and evaluate sleep disturbance in Hong Kong adolescents; to identify factors that are associated with sleep disturbance; and to examine the relationship of sleep-wake variables and academic performance. A school-based cross-sectional survey. Sample included 1629 adolescents aged 12 to 19 years. Self-report questionnaires, including sleep-wake habit questionnaire, Sleep Quality Index, Morningness/ Eveningness scale, Epworth Sleepiness Scale, Perceived Stress Scale, academic performance, and personal data were administered. The average school-night bedtime was 23:24, and total sleep time was 7.3 hr. During weekends, the average bedtime and rise time was delayed by 64 min and 195 min, respectively. The prevalence of sleep disturbances occurring > or = 3 days per week in the preceding 3 months were: difficulty falling asleep (5.6%), waking up during the night (7.2%), and waking up too early in the morning (10.4%). The prevalence of > or = 1 of these three symptoms was 19.1%. Stepwise regression analyses revealed that circadian phase preference was the most significant predictor for school night bedtime, weekend oversleep, and daytime sleepiness. Perceived stress was the most significant risk factor for sleep disturbance. Students with marginal academic performance reported later bedtimes and shorter sleep during school nights, greater weekend delays in bedtime, and more daytime sleepiness than those with better grades. The prevalence of sleep deprivation and sleep disturbance among Hong Kong adolescents is comparable to those found in other countries. An intervention program for sleep problems in adolescents should be considered.

  13. Sleep structure in blindness is influenced by circadian desynchrony

    DEFF Research Database (Denmark)

    Aubin, Sébrina; Jennum, Poul; Nielsen, Tore

    2018-01-01

    We examined the structure, duration and quality of sleep, including non-rapid eye movement sleep and rapid eye movement sleep, in 11 blind individuals without conscious light perception and 11 age- and sex-matched sighted controls. Because blindness is associated with a greater incidence of free......-running circadian rhythms, we controlled for circadian phase by a measure of melatonin onset timing. When circadian rhythm was entrained and melatonin onset occurred at normal times, sleep structure did not differ between blind and sighted individuals. On the other hand, an abnormal timing of the circadian phase......, including delayed, shifted and unclassifiable melatonin onsets, led to larger rapid eye movement sleep latencies and increased wake times. No differences were observed for stages of non-rapid eye movement sleep, either between congenital and late blind and sighted individuals, or across the different...

  14. The developmental feature of the sleep problems in adolescence : The approach for the application to educational stage

    OpenAIRE

    Tanaka, Hideki; Hayashi, Mitsuo; Hori, Tadao

    1997-01-01

    To clarify the actual feature of the sleep problems in adolescence from the points of view sleep loss, circadian rhythm, and development, the survey for five years was performed on 523 students in a College of Technology. The survey results were analyzed in regard to the Sleep Habits Scales and the Life Habits Scales. These scales were (1) Long sleeper-Short sleeper, (2) Good sleeper-Poor sleeper, (3) Sleep phase advanced type-Sleep phase delayed type, (4) Morningness-Eveningness, (5) Regnlar...

  15. Mitosis delay in cells of the root meristem of pea seedlings in S and G2-phases when irradiated with gamma-rays

    International Nuclear Information System (INIS)

    Gudkov, I.N.; Zezina, N.V.

    1976-01-01

    Irradiation (800 rads) of pea seedlings, synchronized by a 24-hr treatment with 0.03% hydroxyurea, at the stage of G 1 →S, induced a 12-hr delay of mitosis peak; an 8-hr delay, in the early S-phase; a 4-hr delay, in the middle of S-phase; a 10-hr delay in the late S- and a 14-16-hr delay, in G 2 -phase. The number of cells having chromosome aberrations at the mitosis peak was similar in all the phases under study

  16. Steady states and outbreaks of two-phase nonlinear age-structured model of population dynamics with discrete time delay.

    Science.gov (United States)

    Akimenko, Vitalii; Anguelov, Roumen

    2017-12-01

    In this paper we study the nonlinear age-structured model of a polycyclic two-phase population dynamics including delayed effect of population density growth on the mortality. Both phases are modelled as a system of initial boundary values problem for semi-linear transport equation with delay and initial problem for nonlinear delay ODE. The obtained system is studied both theoretically and numerically. Three different regimes of population dynamics for asymptotically stable states of autonomous systems are obtained in numerical experiments for the different initial values of population density. The quasi-periodical travelling wave solutions are studied numerically for the autonomous system with the different values of time delays and for the system with oscillating death rate and birth modulus. In both cases it is observed three types of travelling wave solutions: harmonic oscillations, pulse sequence and single pulse.

  17. Effects of Phytoplankton Growth Phase on Delayed Settling Behavior of Marine Snow Aggregates at Sharp Density Transitions

    Science.gov (United States)

    Proctor, K. W.; Montgomery, Q. W.; Prairie, J. C.

    2016-02-01

    Marine snow aggregates play a fundamental role in the marine carbon cycle. Since marine snow aggregates are larger and thus sink faster than individual phytoplankton, aggregates often dominate carbon flux. Previous studies have shown that marine snow aggregates will significantly decrease their settling velocity when passing through sharp density transitions within the ocean, a phenomenon defined as delayed settling. Given the importance of aggregate settling to carbon export, these small-scale changes in aggregate settling dynamics may have significant impacts on the efficiency of the biological pump. However, there is still a lack of knowledge about how different physical properties of aggregates can affect this delayed settling. In this study, we investigated the effect of phytoplankton growth phase on delayed settling behavior. Using phytoplankton cultures stopped at four different growth phases, we formed marine snow aggregates in the laboratory in rotating cylindrical tanks. We then observed individual aggregates as they settled through a stratified tank. We will present data which illustrates that aggregates experience greatly reduced settling rates when passing through sharp density gradients and that the growth phase of the phytoplankton used to form these aggregates has a significant effect on this delayed settling behavior. A thorough understanding of the impact of phytoplankton growth phase on the delayed settling behavior of marine snow will offer insight into the way phytoplankton growth phase may influence the efficiency of the biological pump, carbon flux, and the carbon cycle as a whole.

  18. Tracheal sound parameters of respiratory cycle phases show differences between flow-limited and normal breathing during sleep

    International Nuclear Information System (INIS)

    Kulkas, A; Huupponen, E; Virkkala, J; Saastamoinen, A; Rauhala, E; Tenhunen, M; Himanen, S-L

    2010-01-01

    The objective of the present work was to develop new computational parameters to examine the characteristics of respiratory cycle phases from the tracheal breathing sound signal during sleep. Tracheal sound data from 14 patients (10 males and 4 females) were examined. From each patient, a 10 min long section of normal and a 10 min section of flow-limited breathing during sleep were analysed. The computationally determined proportional durations of the respiratory phases were first investigated. Moreover, the phase durations and breathing sound amplitude levels were used to calculate the area under the breathing sound envelope signal during inspiration and expiration phases. An inspiratory sound index was then developed to provide the percentage of this type of area during the inspiratory phase with respect to the combined area of inspiratory and expiratory phases. The proportional duration of the inspiratory phase showed statistically significantly higher values during flow-limited breathing than during normal breathing and inspiratory pause displayed an opposite difference. The inspiratory sound index showed statistically significantly higher values during flow-limited breathing than during normal breathing. The presented novel computational parameters could contribute to the examination of sleep-disordered breathing or as a screening tool

  19. Sleep quality and circadian rhythm disruption in the intensive care unit

    DEFF Research Database (Denmark)

    Boyko, Yuliya; Jennum, Poul; Toft, Palle

    2017-01-01

    , medication, as well as the critical illness itself have been reported as important sleep disturbing factors. Secretion of sleep hormone, melatonin, expressing circadian rhythmicity was found abolished or phase delayed in critically ill patients. Various interventions have been tested in several studies...... aiming to improve sleep quality and circadian rhythm in the ICU. The results of these studies were inconclusive due to using the sleep assessment methods other than PSG or the absence of a reliable sleep scoring tool for the analysis of the PSG findings in this patient population. Development of a valid...

  20. Trying to fall asleep while catastrophising: what sleep-disordered adolescents think and feel.

    Science.gov (United States)

    Hiller, Rachel M; Lovato, Nicole; Gradisar, Michael; Oliver, Mike; Slater, Amy

    2014-01-01

    Catastrophising is a repetitive cognitive process related to sleep disturbance in adult insomnia patients. More recently catastrophising has been associated with increased sleep disturbances in community samples of children and adolescents, with this association mediated by anxiety and depression. However, there currently is no evidence of these processes outside of community samples; impeding our ability to draw clinical conclusions. Knowledge on such dysfunctional cognitive processes in adolescents experiencing sleep disturbance would be clinically beneficial in aetiology and intervention. Our research examined the link between catastrophising, anxiety, depression and sleep latency in a sample of sleep-disordered adolescents. We also explored specific catastrophising themes which may impact the sleep latency of these adolescents. Forty adolescents (age=15.1±1.5 years, 53% boys) diagnosed with delayed sleep phase disorder completed a 7-day sleep diary, along with measures of anxiety and depression and a catastrophising interview with a trained sleep therapist. Several catastrophisation themes were generated, the most common concerning interpersonal and performance aspects of school. Bootstrapping analyses showed depression did not mediate the relationship between catastrophising and sleep; however, an indirect relationship was found between catastrophising, anticipatory anxiety, and sleep latency. These findings have implications for the role of dysfunctional thinking in prolonging sleep onset for adolescents and providing a clinical framework for health professionals when assessing and treating adolescents with delayed sleep timing. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  1. Hybrid Smith predictor and phase lead based divergence compensation for hardware-in-the-loop contact simulation with measurement delay

    Science.gov (United States)

    Qi, Chenkun; Gao, Feng; Zhao, Xianchao; Wang, Qian; Ren, Anye

    2018-06-01

    On the ground the hardware-in-the-loop (HIL) simulation is a good approach to test the contact dynamics of spacecraft docking process in space. Unfortunately, due to the time delay in the system the HIL contact simulation becomes divergent. However, the traditional first-order phase lead compensation approach still result in a small divergence for the pure time delay. The serial Smith predictor and phase lead compensation approach proposed by the authors recently will lead to an over-compensation and an obvious convergence. In this study, a hybrid Smith predictor and phase lead compensation approach is proposed. The hybrid Smith predictor and phase lead compensation can achieve a higher simulation fidelity with a little convergence. The phase angle of the compensator is analyzed and the stability condition of the HIL simulation system is given. The effectiveness of the proposed compensation approach is tested by simulations on an undamped elastic contact process.

  2. Monitoring of Weekly Sleep Pattern Variations at Home with a Contactless Biomotion Sensor.

    Science.gov (United States)

    Hashizaki, Masanori; Nakajima, Hiroshi; Kume, Kazuhiko

    2015-08-03

    Many people find that their sleep is restricted or disturbed by social obligations, including work. Sleep phase delays can affect an individual's circadian rhythms on the following day and cause daytime sleepiness and/or poor performance. In this study, to examine weekly variations in sleep patterns, we analyzed sleep data for seven-day periods (from Sunday to Saturday) that had been collected from 2914 subjects (aged 20-79 years) over a total of 24,899 subject-weeks using contactless biomotion sensors. On the weekend, the subjects' mean sleep midpoint, bedtime, and wake-up time were delayed by 40, 26 and 53 min, respectively, compared with those seen on weekdays. In addition, on weekdays, the mean difference between the maximum and median sleep midpoint ranged from 35 to 47 min among the subjects in their 20 s-70 s. The weekend delay and weekday variation in the subjects' sleep patterns tended to decrease with age. This study detected sleep pattern disturbances on both weekdays and weekends. The serial changes in weekday bedtimes detected in this study suggest that sleep habits are influenced by changes in the temporal patterns of social activities/duties. We need further study the advantages of getting extra sleep and the disadvantages of sleep pattern disturbances in daily lifestyle.

  3. Monitoring of Weekly Sleep Pattern Variations at Home with a Contactless Biomotion Sensor

    Directory of Open Access Journals (Sweden)

    Masanori Hashizaki

    2015-08-01

    Full Text Available Many people find that their sleep is restricted or disturbed by social obligations, including work. Sleep phase delays can affect an individual’s circadian rhythms on the following day and cause daytime sleepiness and/or poor performance. In this study, to examine weekly variations in sleep patterns, we analyzed sleep data for seven-day periods (from Sunday to Saturday that had been collected from 2914 subjects (aged 20–79 years over a total of 24,899 subject-weeks using contactless biomotion sensors. On the weekend, the subjects’ mean sleep midpoint, bedtime, and wake-up time were delayed by 40, 26 and 53 min, respectively, compared with those seen on weekdays. In addition, on weekdays, the mean difference between the maximum and median sleep midpoint ranged from 35 to 47 min among the subjects in their 20 s–70 s. The weekend delay and weekday variation in the subjects’ sleep patterns tended to decrease with age. This study detected sleep pattern disturbances on both weekdays and weekends. The serial changes in weekday bedtimes detected in this study suggest that sleep habits are influenced by changes in the temporal patterns of social activities/duties. We need further study the advantages of getting extra sleep and the disadvantages of sleep pattern disturbances in daily lifestyle.

  4. Automated delay estimation at signalized intersections : phase I concept and algorithm development.

    Science.gov (United States)

    2011-07-01

    Currently there are several methods to measure the performance of surface streets, but their capabilities in dynamically estimating vehicle delay are limited. The objective of this research is to develop a method to automate traffic delay estimation ...

  5. Sleep Sleeping Patch

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The Sleep Sleeping Patch is a new kind of external patch based on modern sleep medicine research achievements, which uses the internationally advanced transdermal therapeutic system (TTS). The Sleep Sleeping Patch transmits natural sleep inducers such as peppermint and liquorice extracts and melatonin through the skin to induce sleep. Clinical research proves that the Sleep Sleeping Patch can effectively improve insomnia and the quality of sleep. Highly effective: With the modern TTS therapy,

  6. Effects of menstrual cycle phase and oral contraceptives on alertness, cognitive performance, and circadian rhythms during sleep deprivation

    Science.gov (United States)

    Wright, K. P. Jr; Badia, P.; Czeisler, C. A. (Principal Investigator)

    1999-01-01

    The influence of menstrual cycle phase and oral contraceptive use on neurobehavioral function and circadian rhythms were studied in healthy young women (n = 25) using a modified constant routine procedure during 24 h of sleep deprivation. Alertness and performance worsened across sleep deprivation and also varied with circadian phase. Entrained circadian rhythms of melatonin and body temperature were evident in women regardless of menstrual phase or oral contraceptive use. No significant difference in melatonin levels, duration, or phase was observed between women in the luteal and follicular phases, whereas oral contraceptives appeared to increase melatonin levels. Temperature levels were higher in the luteal phase and in oral contraceptive users compared to women in the follicular phase. Alertness on the maintenance of wakefulness test and some tests of cognitive performance were poorest for women in the follicular phase especially near the circadian trough of body temperature. These observations suggest that hormonal changes associated with the menstrual cycle and the use of oral contraceptives contribute to changes in nighttime waking neurobehavioral function and temperature level whereas these factors do not appear to affect circadian phase.

  7. Mammalian sleep

    Science.gov (United States)

    Staunton, Hugh

    2005-05-01

    This review examines the biological background to the development of ideas on rapid eye movement sleep (REM sleep), so-called paradoxical sleep (PS), and its relation to dreaming. Aspects of the phenomenon which are discussed include physiological changes and their anatomical location, the effects of total and selective sleep deprivation in the human and animal, and REM sleep behavior disorder, the latter with its clinical manifestations in the human. Although dreaming also occurs in other sleep phases (non-REM or NREM sleep), in the human, there is a contingent relation between REM sleep and dreaming. Thus, REM is taken as a marker for dreaming and as REM is distributed ubiquitously throughout the mammalian class, it is suggested that other mammals also dream. It is suggested that the overall function of REM sleep/dreaming is more important than the content of the individual dream; its function is to place the dreamer protagonist/observer on the topographical world. This has importance for the developing infant who needs to develop a sense of self and separateness from the world which it requires to navigate and from which it is separated for long periods in sleep. Dreaming may also serve to maintain a sense of ‘I’ness or “self” in the adult, in whom a fragility of this faculty is revealed in neurological disorders.

  8. Coherent control of interfering wave packets in dissociating HD+ molecules: the role of phase and delay time

    International Nuclear Information System (INIS)

    Qin, Chaochao; Zhang, Lili; Zhang, Xianzhou; Liu, Yufang; Qiu, Xuejun

    2016-01-01

    The coherent control of interference between dissociating wave packets of the HD + molecules generated by a pair of time-delayed and phase-locked femtosecond laser pulses is theoretically studied by using the time-dependent quantum wave packet method. The density function in both coordinate and momentum representation are presented and discussed. It is demonstrated that the interference pattern is observed in both coordinate and momentum density functions. The interference undergoes a π-phase shift when the delay time between the two phase-locked femtosecond laser pulses is changed by half an optical period. In particular, the number of interference fringes, the fringe spacing in the R-dependent density distribution |ψ(R)| 2 , and the modulation period of the energy-dependent distribution of the fragments P(E) can be tuned by two phase-locked femtosecond pulses. (paper)

  9. The effect of the inter-phase delay interval in the spontaneous object recognition test for pigs

    DEFF Research Database (Denmark)

    Kornum, Birgitte Rahbek; Thygesen, Kristin Sjølie; Nielsen, Thomas Rune

    2007-01-01

    In the neuroscience community interest for using the pig is growing. Several disease models have been developed creating a need for validation of behavioural paradigms in these animals. Here, we report the effect of different inter-phase delay intervals on the performance of Göttingen minipigs...

  10. Sleep, arousal, and circadian rhythms in adults with obsessive-compulsive disorder: a meta-analysis.

    Science.gov (United States)

    Nota, Jacob A; Sharkey, Katherine M; Coles, Meredith E

    2015-04-01

    Findings of this meta-analysis show that obsessive-compulsive disorder (OCD) is related to disruptions in both the duration and timing of sleep. PsycINFO and Google Scholar database searches identified 12 relevant studies that compared measures of sleep in individuals with OCD to those of either a healthy control group or published norms. Sleep measures included sleep onset latency, sleep duration, awakening after sleep onset, percentage of rapid eye movement (REM) sleep, percentage of slow wave sleep, and prevalence of delayed sleep phase disorder (DSPD). Individual effect sizes were pooled using a random effects model. Sleep duration was found to be shorter, and the prevalence of DSPD higher, in individuals with OCD compared to controls. Further, excluding samples with comorbid depression did not meaningfully reduce the magnitude of these effects (although the results were no longer statistically significant) and medication use by participants is unlikely to have systematically altered sleep timing. Overall, available data suggest that sleep disruption is associated with OCD but further research on both sleep duration and sleep timing in individuals with OCD is needed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Delayed-Phase Cone-Beam CT Improves Detectability of Intrahepatic Cholangiocarcinoma During Conventional Transarterial Chemoembolization

    International Nuclear Information System (INIS)

    Schernthaner, Ruediger Egbert; Lin, MingDe; Duran, Rafael; Chapiro, Julius; Wang, Zhijun; Geschwind, Jean-François

    2015-01-01

    PurposeTo evaluate the detectability of intrahepatic cholangiocarcinoma (ICC) on dual-phase cone-beam CT (DPCBCT) during conventional transarterial chemoembolization (cTACE) compared to that of digital subtraction angiography (DSA) with respect to pre-procedure contrast-enhanced magnetic resonance imaging (CE-MRI) of the liver.MethodsThis retrospective study included 17 consecutive patients (10 male, mean age 64) with ICC who underwent pre-procedure CE-MRI of the liver, and DSA and DPCBCT (early-arterial phase (EAP) and delayed-arterial phase (DAP)) just before cTACE. The visibility of each ICC lesion was graded by two radiologists on a three-rank scale (complete, partial, and none) on DPCBCT and DSA images, and then compared to pre-procedure CE-MRI.ResultsOf 61 ICC lesions, only 45.9 % were depicted by DSA, whereas EAP- and DAP-CBCT yielded a significantly higher detectability rate of 73.8 % and 93.4 %, respectively (p < 0.01). Out of the 33 lesions missed on DSA, 18 (54.5 %) and 30 (90.9 %) were revealed on EAP- and DAP-CBCT images, respectively. DSA depicted only one lesion that was missed by DPCBCT due to streak artifacts caused by a prosthetic mitral valve. DAP-CBCT identified significantly more lesions than EAP-CBCT (p < 0.01). Conversely, EAP-CBCT did not detect lesions missed by DAP-CBCT. For complete lesion visibility, DAP-CBCT yielded significantly higher detectability (78.7 %) compared to EAP (31.1 %) and DSA (21.3 %) (p < 0.01).ConclusionDPCBCT, and especially the DAP-CBCT, significantly improved the detectability of ICC lesions during cTACE compared to DSA. We recommend the routine use of DAP-CBCT in patients with ICC for per-procedure detectability and treatment planning in the setting of TACE

  12. Delayed-Phase Cone-Beam CT Improves Detectability of Intrahepatic Cholangiocarcinoma During Conventional Transarterial Chemoembolization

    Energy Technology Data Exchange (ETDEWEB)

    Schernthaner, Ruediger Egbert [The Johns Hopkins Hospital, Russell H. Morgan Department of Radiology and Radiological Science, Division of Vascular and Interventional Radiology (United States); Lin, MingDe [Philips Research North America, Ultrasound and Interventions (United States); Duran, Rafael; Chapiro, Julius; Wang, Zhijun; Geschwind, Jean-François, E-mail: jfg@jhmi.edu [The Johns Hopkins Hospital, Russell H. Morgan Department of Radiology and Radiological Science, Division of Vascular and Interventional Radiology (United States)

    2015-08-15

    PurposeTo evaluate the detectability of intrahepatic cholangiocarcinoma (ICC) on dual-phase cone-beam CT (DPCBCT) during conventional transarterial chemoembolization (cTACE) compared to that of digital subtraction angiography (DSA) with respect to pre-procedure contrast-enhanced magnetic resonance imaging (CE-MRI) of the liver.MethodsThis retrospective study included 17 consecutive patients (10 male, mean age 64) with ICC who underwent pre-procedure CE-MRI of the liver, and DSA and DPCBCT (early-arterial phase (EAP) and delayed-arterial phase (DAP)) just before cTACE. The visibility of each ICC lesion was graded by two radiologists on a three-rank scale (complete, partial, and none) on DPCBCT and DSA images, and then compared to pre-procedure CE-MRI.ResultsOf 61 ICC lesions, only 45.9 % were depicted by DSA, whereas EAP- and DAP-CBCT yielded a significantly higher detectability rate of 73.8 % and 93.4 %, respectively (p < 0.01). Out of the 33 lesions missed on DSA, 18 (54.5 %) and 30 (90.9 %) were revealed on EAP- and DAP-CBCT images, respectively. DSA depicted only one lesion that was missed by DPCBCT due to streak artifacts caused by a prosthetic mitral valve. DAP-CBCT identified significantly more lesions than EAP-CBCT (p < 0.01). Conversely, EAP-CBCT did not detect lesions missed by DAP-CBCT. For complete lesion visibility, DAP-CBCT yielded significantly higher detectability (78.7 %) compared to EAP (31.1 %) and DSA (21.3 %) (p < 0.01).ConclusionDPCBCT, and especially the DAP-CBCT, significantly improved the detectability of ICC lesions during cTACE compared to DSA. We recommend the routine use of DAP-CBCT in patients with ICC for per-procedure detectability and treatment planning in the setting of TACE.

  13. Temporal correlations between sensitivity to radiation-induced mitotic delay and the S phase of the sea urchin egg

    International Nuclear Information System (INIS)

    Rustad, R.C.; Viswanathan, G.; Antonellis, B.C.

    1979-01-01

    Separate samples of eggs from the sea urchin Arbacia punctulata were gamma irradiated (4kR) at different times after fertilisation and division delay measured. The results demonstrated a characteristic post-fertilisation pattern of a rise in sensitivity to radiation-induced mitotic delay, followed by a biphasic decrease in sensitivity to a refractory period. Measurements of the cumulative incorporation of 3 H-TdR showed that the first period of decreasing radiation sensitivity was closely associated with the bulk synthesis of DNA (S phase). (U.K.)

  14. Estimating fuel octane numbers from homogeneous gas-phase ignition delay times

    KAUST Repository

    Naser, Nimal

    2017-11-05

    Fuel octane numbers are directly related to the autoignition properties of fuel/air mixtures in spark ignition (SI) engines. This work presents a methodology to estimate the research and the motor octane numbers (RON and MON) from homogeneous gas-phase ignition delay time (IDT) data calculated at various pressures and temperatures. The hypothesis under investigation is that at specific conditions of pressure and temperature (i.e., RON-like and MON-like conditions), fuels with IDT identical to that of a primary reference fuel (PRF) have the same octane rating. To test this hypothesis, IDTs with a detailed gasoline surrogate chemical kinetic model have been calculated at various temperatures and pressures. From this dataset, temperatures that best represent RON and MON have been correlated at a specified pressure. Correlations for pressures in the range of 10–50 bar were obtained. The proposed correlations were validated with toluene reference fuels (TRF), toluene primary reference fuels (TPRF), ethanol reference fuels (ERF), PRFs and TPRFs with ethanol, and multi-component gasoline surrogate mixtures. The predicted RON and MON showed satisfactory accuracy against measurements obtained by the standard ASTM methods and blending rules, demonstrating that the present methodology can be a viable tool for a first approximation. The correlations were also validated against an extensive set of experimental IDT data obtained from literature with a high degree of accuracy in RON/MON prediction. Conditions in homogeneous reactors such as shock tubes and rapid compression machines that are relevant to modern SI engines were also identified. Uncertainty analysis of the proposed correlations with linear error propagation theory is also presented.

  15. Estimating fuel octane numbers from homogeneous gas-phase ignition delay times

    KAUST Repository

    Naser, Nimal; Sarathy, Mani; Chung, Suk-Ho

    2017-01-01

    Fuel octane numbers are directly related to the autoignition properties of fuel/air mixtures in spark ignition (SI) engines. This work presents a methodology to estimate the research and the motor octane numbers (RON and MON) from homogeneous gas-phase ignition delay time (IDT) data calculated at various pressures and temperatures. The hypothesis under investigation is that at specific conditions of pressure and temperature (i.e., RON-like and MON-like conditions), fuels with IDT identical to that of a primary reference fuel (PRF) have the same octane rating. To test this hypothesis, IDTs with a detailed gasoline surrogate chemical kinetic model have been calculated at various temperatures and pressures. From this dataset, temperatures that best represent RON and MON have been correlated at a specified pressure. Correlations for pressures in the range of 10–50 bar were obtained. The proposed correlations were validated with toluene reference fuels (TRF), toluene primary reference fuels (TPRF), ethanol reference fuels (ERF), PRFs and TPRFs with ethanol, and multi-component gasoline surrogate mixtures. The predicted RON and MON showed satisfactory accuracy against measurements obtained by the standard ASTM methods and blending rules, demonstrating that the present methodology can be a viable tool for a first approximation. The correlations were also validated against an extensive set of experimental IDT data obtained from literature with a high degree of accuracy in RON/MON prediction. Conditions in homogeneous reactors such as shock tubes and rapid compression machines that are relevant to modern SI engines were also identified. Uncertainty analysis of the proposed correlations with linear error propagation theory is also presented.

  16. VLF group delay of lightning-induced electron precipitation echoes from measurement of phase and amplitude perturbations at two frequencies

    International Nuclear Information System (INIS)

    Adams, C.D.D.; Dowden, R.L.

    1990-01-01

    Measurement of phase and amplitude perturbations (trimpis) of the NWC signal at Dunedin at both the NWC frequencies, 22,250 Hz and 22,350 Hz, enables measurement of the received phase of the echo signal (phasor difference of the perturbed and unperturbed signals) at each frequency and so the rate of decrease of phase with frequency. This, of course, is the group delay. The 100-Hz difference implies that measurement of echo group delays of up to 5 ms could be made without ambiguity, though other factors limit this to about 2.5 ms. Some 38 difference trimpis during May and June 1988 showed echo delays up to 2 ms corresponding to reflection from points displaced more than 1,000 km from the NWC-Dunedin great circle path. The echo amplitudes observed at such large displacements are much greater than expected from smooth circular depressions of the ionosphere modifying the waveguide phase velocity and so imply sharper discontinuities in the waveguide

  17. Graphene-based fine-tunable optical delay line for optical beamforming in phased-array antennas.

    Science.gov (United States)

    Tatoli, Teresa; Conteduca, Donato; Dell'Olio, Francesco; Ciminelli, Caterina; Armenise, Mario N

    2016-06-01

    The design of an integrated graphene-based fine-tunable optical delay line on silicon nitride for optical beamforming in phased-array antennas is reported. A high value of the optical delay time (τg=920  ps) together with a compact footprint (4.15  mm2) and optical loss graphene-based Mach-Zehnder interferometer switches and two vertically stacked microring resonators between which a graphene capacitor is placed. The tuning range is obtained by varying the value of the voltage applied to the graphene electrodes, which controls the optical path of the light propagation and therefore the delay time. The graphene provides a faster reconfigurable time and low values of energy dissipation. Such significant advantages, together with a negligible beam-squint effect, allow us to overcome the limitations of conventional RF beamformers. A highly efficient fine-tunable optical delay line for the beamsteering of 20 radiating elements up to ±20° in the azimuth direction of a tile in a phased-array antenna of an X-band synthetic aperture radar has been designed.

  18. Study of the phase delay in the amplitude-modulated harmonic oscillator

    International Nuclear Information System (INIS)

    Krupska, Aldona; Krupski, Marcin

    2003-01-01

    The delayed response of a damped harmonic oscillator (RLC circuit) to a slow periodic disturbance is presented. This communication is supplementary to the paper published recently (Krupska et al 2001 Eur. J. Phys. 22 133-8)

  19. Segmented Spiral Waves and Anti-phase Synchronization in a Model System with Two Identical Time-Delayed Coupled Layers

    International Nuclear Information System (INIS)

    Yuan Guoyong; Yang Shiping; Wang Guangrui; Chen Shigang

    2008-01-01

    In this paper, we consider a model system with two identical time-delayed coupled layers. Synchronization and anti-phase synchronization are exhibited in the reactive system without diffusion term. New segmented spiral waves, which are constituted by many thin trips, are found in each layer of two identical time-delayed coupled layers, and are different from the segmented spiral waves in a water-in-oil aerosol sodium bis(2-ethylhexyl) sulfosuccinate (AOT) micro-emulsion (ME) (BZ-AOT system), which consists of many small segments. 'Anti-phase spiral wave synchronization' can be realized between the first layer and the second one. For different excitable parameters, we also give the minimum values of the coupling strength to generate segmented spiral waves and the tip orbits of spiral waves in the whole bilayer.

  20. Sleep quality and circadian rhythm disruption in the intensive care unit

    DEFF Research Database (Denmark)

    Boyko, Yuliya; Jennum, Poul; Toft, Palle

    2017-01-01

    Sleep and circadian rhythm are reported to be severely abnormal in critically ill patients. Disturbed sleep can lead to the development of delirium and, as a result, can be associated with prolonged stay in the intensive care unit (ICU) and increased mortality. The standard criterion method...... aiming to improve sleep quality and circadian rhythm in the ICU. The results of these studies were inconclusive due to using the sleep assessment methods other than PSG or the absence of a reliable sleep scoring tool for the analysis of the PSG findings in this patient population. Development of a valid......, medication, as well as the critical illness itself have been reported as important sleep disturbing factors. Secretion of sleep hormone, melatonin, expressing circadian rhythmicity was found abolished or phase delayed in critically ill patients. Various interventions have been tested in several studies...

  1. Staphylococcus aureus-induced G2/M phase transition delay in host epithelial cells increases bacterial infective efficiency.

    Directory of Open Access Journals (Sweden)

    Ludmila Alekseeva

    Full Text Available Staphylococcus aureus is a highly versatile, opportunistic pathogen and the etiological agent of a wide range of infections in humans and warm-blooded animals. The epithelial surface is its principal site of colonization and infection. In this work, we investigated the cytopathic effect of S. aureus strains from human and animal origins and their ability to affect the host cell cycle in human HeLa and bovine MAC-T epithelial cell lines. S. aureus invasion slowed down cell proliferation and induced a cytopathic effect, resulting in the enlargement of host cells. A dramatic decrease in the number of mitotic cells was observed in the infected cultures. Flow cytometry analysis revealed an S. aureus-induced delay in the G2/M phase transition in synchronous HeLa cells. This delay required the presence of live S. aureus since the addition of the heat-killed bacteria did not alter the cell cycle. The results of Western blot experiments showed that the G2/M transition delay was associated with the accumulation of inactive cyclin-dependent kinase Cdk1, a key inducer of mitosis entry, and with the accumulation of unphosphorylated histone H3, which was correlated with a reduction of the mitotic cell number. Analysis of S. aureus proliferation in asynchronous, G1- and G2-phase-enriched HeLa cells showed that the G2 phase was preferential for bacterial infective efficiency, suggesting that the G2 phase delay may be used by S. aureus for propagation within the host. Taken together, our results divulge the potential of S. aureus in the subversion of key cellular processes such as cell cycle progression, and shed light on the biological significance of S. aureus-induced host cell cycle alteration.

  2. Accommodating adolescent sleep-wake patterns: the effects of shifting the timing of sleep on training effectiveness.

    Science.gov (United States)

    Miller, Nita Lewis; Tvaryanas, Anthony P; Shattuck, Lawrence G

    2012-08-01

    This study evaluated the effect of accommodating adolescent sleep-wake patterns by altering the timing of the major sleep period of US Army recruits. The quasi-experimental study compared recruits assigned to one of two training companies: one with a customary sleep regimen (20:30 to 04:30) while the other employed a phase-delayed sleep regimen (23:00 to 07:00), the latter aligning better with biologically driven sleep-wake patterns of adolescents. The study was conducted during Basic Combat Training (BCT) at Fort Leonard Wood, Missouri. TRAINEES: The study included 392 trainees: 209 received the intervention, while 183 composed the Comparison group. Demographic and psychophysiological measures were collected on all trainees. Weekly assessments of subjective fatigue and mood, periodic physical fitness, marksmanship scores, and attrition rates from BCT were studied. Actigraphy was collected on approximately 24% of trainees. Based on actigraphy, trainees on the phase-delayed sleep schedule obtained 31 m more sleep/night than trainees on the customary sleep schedule. The Intervention group reported less total mood disturbance relative to baseline. Improvements in marksmanship correlated positively with average nightly sleep during the preceding week when basic marksmanship skills were taught. No differences were seen in physical fitness or attrition rates. In contrast to the Intervention group, the Comparison group was 2.3 times more likely to experience occupationally significant fatigue and 5.5 times more likely to report poor sleep quality. Accommodating adolescent sleep patterns significantly improves mental health and performance in the training environment.

  3. Sleep-wake habits in middle and late adolescence and the criteria for the choice of subjects on sleep research

    OpenAIRE

    林, 光緒; 田中, 秀樹; 岩城, 達也; 福田, 一彦; 堀, 忠雄

    1997-01-01

    Sleep-wake habits in middle and late adolescence were surveyed for college of technology (n=799), college of nursing (n=460) and university (n=1062) students. Daytime sleepiness and nodding off were often occurred. They made up for shortened sleep time at holiday. One third of them took replacement naps. Some of them had the irregular life habits, such as delayed bed-time, shortened sleep time, irregular meal time and engaging in night work, suggesting that these habits might alter the phase ...

  4. Multi-GNSS phase delay estimation and PPP ambiguity resolution: GPS, BDS, GLONASS, Galileo

    Science.gov (United States)

    Li, Xingxing; Li, Xin; Yuan, Yongqiang; Zhang, Keke; Zhang, Xiaohong; Wickert, Jens

    2018-06-01

    This paper focuses on the precise point positioning (PPP) ambiguity resolution (AR) using the observations acquired from four systems: GPS, BDS, GLONASS, and Galileo (GCRE). A GCRE four-system uncalibrated phase delay (UPD) estimation model and multi-GNSS undifferenced PPP AR method were developed in order to utilize the observations from all systems. For UPD estimation, the GCRE-combined PPP solutions of the globally distributed MGEX and IGS stations are performed to obtain four-system float ambiguities and then UPDs of GCRE satellites can be precisely estimated from these ambiguities. The quality of UPD products in terms of temporal stability and residual distributions is investigated for GPS, BDS, GLONASS, and Galileo satellites, respectively. The BDS satellite-induced code biases were corrected for GEO, IGSO, and MEO satellites before the UPD estimation. The UPD results of global and regional networks were also evaluated for Galileo and BDS, respectively. As a result of the frequency-division multiple-access strategy of GLONASS, the UPD estimation was performed using a network of homogeneous receivers including three commonly used GNSS receivers (TRIMBLE NETR9, JAVAD TRE_G3TH DELTA, and LEICA). Data recorded from 140 MGEX and IGS stations for a 30-day period in January in 2017 were used to validate the proposed GCRE UPD estimation and multi-GNSS dual-frequency PPP AR. Our results show that GCRE four-system PPP AR enables the fastest time to first fix (TTFF) solutions and the highest accuracy for all three coordinate components compared to the single and dual system. An average TTFF of 9.21 min with 7{°} cutoff elevation angle can be achieved for GCRE PPP AR, which is much shorter than that of GPS (18.07 min), GR (12.10 min), GE (15.36 min) and GC (13.21 min). With observations length of 10 min, the positioning accuracy of the GCRE fixed solution is 1.84, 1.11, and 1.53 cm, while the GPS-only result is 2.25, 1.29, and 9.73 cm for the east, north, and vertical

  5. Improvement of a patient's circadian rhythm sleep disorders by aripiprazole was associated with stabilization of his bipolar illness.

    Science.gov (United States)

    Tashiro, Tetsuo

    2017-04-01

    Splitting of the behavioural activity phase has been found in nocturnal rodents with suprachiasmatic nucleus (SCN) coupling disorder. A similar phenomenon was observed in the sleep phase in the diurnal human discussed here, suggesting that there are so-called evening and morning oscillators in the SCN of humans. The present case suffered from bipolar disorder refractory to various treatments, and various circadian rhythm sleep disorders, such as delayed sleep phase, polyphasic sleep, separation of the sleep bout resembling splitting and circabidian rhythm (48 h), were found during prolonged depressive episodes with hypersomnia. Separation of sleep into evening and morning components and delayed sleep-offset (24.69-h cycle) developed when lowering and stopping the dose of aripiprazole (APZ). However, resumption of APZ improved these symptoms in 2 weeks, accompanied by improvement in the patient's depressive state. Administration of APZ may improve various circadian rhythm sleep disorders, as well as improve and prevent manic-depressive episodes, via augmentation of coupling in the SCN network. © 2017 The Authors. Journal of Sleep Research published by John Wiley & Sons Ltd on behalf of European Sleep Research Society.

  6. Sleep and Eating Disorders.

    Science.gov (United States)

    Allison, Kelly C; Spaeth, Andrea; Hopkins, Christina M

    2016-10-01

    Insomnia is related to an increased risk of eating disorders, while eating disorders are related to more disrupted sleep. Insomnia is also linked to poorer treatment outcomes for eating disorders. However, over the last decade, studies examining sleep and eating disorders have relied on surveys, with no objective measures of sleep for anorexia nervosa or bulimia nervosa, and only actigraphy data for binge eating disorder. Sleep disturbance is better defined for night eating syndrome, where sleep efficiency is reduced and melatonin release is delayed. Studies that include objectively measured sleep and metabolic parameters combined with psychiatric comorbidity data would help identify under what circumstances eating disorders and sleep disturbance produce an additive effect for symptom severity and for whom poor sleep would increase risk for an eating disorder. Cognitive behavior therapy for insomnia may be a helpful addition to treatment of those with both eating disorder and insomnia.

  7. Diagnostic and Treatment Challenges of Sighted Non-24-Hour Sleep-Wake Disorder.

    Science.gov (United States)

    Malkani, Roneil G; Abbott, Sabra M; Reid, Kathryn J; Zee, Phyllis C

    2018-04-15

    To report the diagnostic and treatment challenges of sighted non-24-hour sleep-wake disorder (N24SWD). We report a series of seven sighted patients with N24SWD clinically evaluated by history and sleep diaries, and when available wrist actigraphy and salivary melatonin levels, and treated with timed melatonin and bright light therapy. Most patients had a history of a delayed sleep-wake pattern prior to developing N24SWD. The typical sleep-wake pattern of N24SWD was seen in the sleep diaries (and in actigraphy when available) in all patients with a daily delay in midpoint of sleep ranging 0.8 to 1.8 hours. Salivary dim light melatonin onset (DLMO) was evaluated in four patients but was missed in one. The estimated phase angle from DLMO to sleep onset ranged from 5.25 to 9 hours. All six patients who attempted timed melatonin and bright light therapy were able to entrain their sleep-wake schedules. Entrainment occurred at a late circadian phase, possibly related to the late timing of melatonin administration, though the patients often preferred late sleep times. Most did not continue treatment and continued to have a non-24-hour sleep-wake pattern. N24SWD is a chronic debilitating disorder that is often overlooked in sighted people and can be challenging to diagnose and treat. Tools to assess circadian pattern and timing can be effectively applied to aid the diagnosis. The progressive delay of the circadian rhythm poses a challenge for determining the most effective timing for melatonin and bright light therapies. Furthermore, once the circadian sleep-wake rhythm is entrained, long-term effectiveness is limited because of the behavioral and environmental structure that is required to maintain stable entrainment. © 2018 American Academy of Sleep Medicine.

  8. Association of sleep and academic performance.

    Science.gov (United States)

    Eliasson, Arne; Eliasson, Anders; King, Joseph; Gould, Ben; Eliasson, Arn

    2002-03-01

    Poor school performance by adolescent students has been attributed in part to insufficient sleep. It is recognized that a number of factors lead to diminished total sleep time and chief among these are early school start times and sleep phase delay in adolescence. Political initiatives are gaining momentum across the United States to require later school start times with the intent of increasing total sleep time and consequently improving school performance. Later school start times come with significant costs and impact other activities of families and communities. The decision to implement later school start times cannot be made lightly and deserves support of well-performed research on the impact of these changes. A study evaluating the association of academic performance and total sleep time was performed in middle school and high school students in a suburban Maryland school system. Preliminary results of this study show no correlation of total sleep time with academic performance. Before mandating costly changes in school schedules, it would be useful to perform further research to determine the effects of increasing sleep time on the behaviors of adolescent students.

  9. Changing Adolescent Sleep Patterns: Factors Affecting them and the Related Problems.

    Science.gov (United States)

    Kaur, Harpreet; Bhoday, Harpreet Singh

    2017-03-01

    Sleep affects physical growth, behavior and emotional development besides determining cognitive functioning, learning and attention especially of a growing child. Adolescence represents one of the critical transitions in the life span and is characterized by a tremendous pace in growth and change that is second only to that of infancy. Adolescent sleep patterns deserve particular attention because of the potential impact on school performance. Average sleep period in adolescents is reduced during school days to around seven hours. The reasons may be biological mainly the sleep phase delay or psychosocial and environmental. These include academic demands, social activities, sports, internet, television viewing, part-time employment, and use of mobile phone at night, peer and parental influence and socioeconomic status. These changing patterns of sleep in adolescents lead to many behavioral sleep problems like Delayed Sleep-phase Syndrome; Difficulties in falling asleep (insomnia); excessive daytime sleepiness, poor academic performance. Decreased sleep in adolescents also causes obesity and other cardio-metabolic abnormalities. This needs an integrated approach involving adolescents themselves, their parents, teachers and specialized physicians to help improve the sleep quantity and quality and lead to a better quality of life and daytime functioning in adolescents. © Journal of the Association of Physicians of India 2011.

  10. Vertical propagation of waves in the solar atmosphere. II. Phase delays in the quiet chromosphere and cell-network distinctions

    International Nuclear Information System (INIS)

    Lites, B.W.; Chipman, E.G.; White, O.R.

    1982-01-01

    The differences in the phase of the velocity oscillations between a pair of chromospheric Ca II lines was measured using the Vacuum Tower Telescope at the Sacramento Peak Observatory. The observed phase differences indicate that the acoustic modes are trapped or envanescent, rather than propagating in the chromosphere. We find systematic distinctions in the phase delays between quiet network and cell interior regions for both intensity and velocity oscillations in photospheric and chromospheric lines. The theory of linear perturbations in a isothermal atmosphere is invoked to interpret these differences. From this analysis we find that one or more of the following explanations is possible. (1) the radiative damping is more effective in the network than in the cell interior; (2) the network features exclude oscillations of large horizontal wavenumber; or (3) the scale height of the chromosphere is larger in the network than in the cell interior

  11. Phase I trials using Sleeping Beauty to generate CD19-specific CAR T cells

    OpenAIRE

    Kebriaei, Partow; Singh, Harjeet; Huls, M. Helen; Figliola, Matthew J.; Bassett, Roland; Olivares, Simon; Jena, Bipulendu; Dawson, Margaret J.; Kumaresan, Pappanaicken R.; Su, Shihuang; Maiti, Sourindra; Dai, Jianliang; Moriarity, Branden; Forget, Marie-Andrée; Senyukov, Vladimir

    2016-01-01

    BACKGROUND. T cells expressing antigen-specific chimeric antigen receptors (CARs) improve outcomes for CD19-expressing B cell malignancies. We evaluated a human application of T cells that were genetically modified using the Sleeping Beauty (SB) transposon/transposase system to express a CD19-specific CAR.

  12. Dopamine agonist suppression of rapid-eye-movement sleep is secondary to sleep suppression mediated via limbic structures

    Energy Technology Data Exchange (ETDEWEB)

    Miletich, R.S.

    1985-01-01

    The effects of pergolide, a direct dopamine receptor agonist, on sleep and wakefulness, motor behavior and /sup 3/H-spiperone specific binding in limbic structures and striatum in rats was studied. The results show that pergolide induced a biphasic dose effect, with high doses increasing wakefulness and suppressing sleep while low dose decreased wakefulness, but increased sleep. It was shown that pergolide-induced sleep suppression was blocked by ..cap alpha..-glupenthixol and pimozide, two dopamine receptor antagonists. It was further shown that pergolide merely delayed the rebound resulting from rapid-eye-movement (REM) sleep deprivation, that dopamine receptors stimulation had no direct effect on the period, phase or amplitude of the circadian rhythm of REM sleep propensity and that there was no alteration in the coupling of REM sleep episodes with S/sub 2/ episodes. Rapid-eye-movement sleep deprivation resulted in increased sensitivity to the pergolide-induced wakefulness stimulation and sleep suppression and pergolide-induced motor behaviors of locomotion and head bobbing. /sup 3/H-spiperone specific binding to dopamine receptors was shown to be altered by REM sleep deprivation in the subcortical limbic structures. It is concluded that the REM sleep suppressing action of dopamine receptor stimulation is secondary to sleep suppression per se and not secondary to a unique effect on the REM sleep. Further, it is suggested that the wakefulness stimulating action of dopamine receptor agonists is mediated by activation of the dopamine receptors in the terminal areas of the mesolimbocortical dopamine projection system.

  13. Sleep Problems in Infants Decrease following Massage Therapy.

    Science.gov (United States)

    Field, Tiffany; Hernandez-Reif, Maria

    2001-01-01

    Examined the effectiveness of pre-bedtime massages for infants and toddlers with sleep onset problems. Found that, compared to bedtime stories, massages produced fewer sleep delays and a shortened latency to sleep onset. (Author/DLH)

  14. Adolescents' sleep behaviors and perceptions of sleep.

    Science.gov (United States)

    Noland, Heather; Price, James H; Dake, Joseph; Telljohann, Susan K

    2009-05-01

    Sleep duration affects the health of children and adolescents. Shorter sleep durations have been associated with poorer academic performance, unintentional injuries, and obesity in adolescents. This study extends our understanding of how adolescents perceive and deal with their sleep issues. General education classes were randomly selected from a convenience sample of three high schools in the Midwest. Three hundred eighty-four ninth- to twelfth-grade students (57%) completed a self-administered valid and reliable questionnaire on sleep behaviors and perceptions of sleep. Most respondents (91.9%) obtained inadequate sleep (sleep each week night. The majority indicated that not getting enough sleep had the following effects on them: being more tired during the day (93.7%), having difficulty paying attention (83.6%), lower grades (60.8%), increase in stress (59.0%), and having difficulty getting along with others (57.7%). Some students reported engaging in harmful behaviors to help them sleep: taking sleeping pills (6.0%), smoking a cigarette to relax (5.7%), and drinking alcohol in the evening (2.9%). Students who received fewer hours of sleep were significantly more likely to report being stressed (p = .02) and were more likely to be overweight (p = .04). Inadequate sleep time may be contributing to adolescent health problems such as increased stress and obesity. Findings indicate a need for sleep hygiene education for adolescents and their parents. A long-term solution to chronic sleep deprivation among high school students could include delaying high school start times, such as was done successfully in the Minneapolis Public School District.

  15. Different phase delays of peripheral input to primate motor cortex and spinal cord promote cancellation at physiological tremor frequencies.

    Science.gov (United States)

    Koželj, Saša; Baker, Stuart N

    2014-05-01

    Neurons in the spinal cord and motor cortex (M1) are partially phase-locked to cycles of physiological tremor, but with opposite phases. Convergence of spinal and cortical activity onto motoneurons may thus produce phase cancellation and a reduction in tremor amplitude. The mechanisms underlying this phase difference are unknown. We investigated coherence between spinal and M1 activity with sensory input. In two anesthetized monkeys, we electrically stimulated the medial, ulnar, deep radial, and superficial radial nerves; stimuli were timed as independent Poisson processes (rate 10 Hz). Single units were recorded from M1 (147 cells) or cervical spinal cord (61 cells). Ninety M1 cells were antidromically identified as pyramidal tract neurons (PTNs); M1 neurons were additionally classified according to M1 subdivision (rostral/caudal, M1r/c). Spike-stimulus coherence analysis revealed significant coupling over a broad range of frequencies, with the strongest coherence at <50 Hz. Delays implied by the slope of the coherence phase-frequency relationship were greater than the response onset latency, reflecting the importance of late response components for the transmission of oscillatory inputs. The spike-stimulus coherence phase over the 6-13 Hz physiological tremor band differed significantly between M1 and spinal cells (phase differences relative to the cord of 2.72 ± 0.29 and 1.72 ± 0.37 radians for PTNs from M1c and M1r, respectively). We conclude that different phases of the response to peripheral input could partially underlie antiphase M1 and spinal cord activity during motor behavior. The coordinated action of spinal and cortical feedback will act to reduce tremulous oscillations, possibly improving the overall stability and precision of motor control. Copyright © 2014 the American Physiological Society.

  16. Gadobenate dimeglumine-enhanced MR of VX2 carcinoma in rabbit liver: usefulness of the delayed phase imaging and optimal pulse sequence

    International Nuclear Information System (INIS)

    Cho, Seung Il; Lee, Jeong Min; Kim, Young Kon; Kim, Chong Soo

    2002-01-01

    To assess the diagnostic value of delayed imaging using gadobenate dimeglumine (MultiHance) and to determine the optimal pulse sequence for the detection of VX2 carcinoma lesions in the rabbit. Twelve VX2 carcinomas implanted in the livers of eleven New Zealand rabbits were studied. All patients underwent an MR protocal consisting of precontrast T2-and T1-weighted sequences, followed by repetition of the T1-weighted sequence at 0 to 30 (arterial phase). 31-60 (portal phase), and 40 minutes (delayed phase) after the intravenous administration of 0.1 mmol/kg of gadobenate dimeglumine. The signal-to-noise ratio (SNR) of the liver and VX2 tumor, and the lesion-to-liver contrast-to-noise ratio (CNR) of precontrast and postcontrast MR images were quantitatively analyzed, and two experienced radiologists evaluated image quality in terms of lesion conspicuity, artifact, mass delineation, and vascular anatomy. Liver SNR was significantly higher at delayed imaging than at precontrast, arterial, and portal imaging (p<0.05), while lesion SNR was significantly higher at delayed imaging than at precontrast imaging (p<0.05). Lesion CNR was higher at delayed imaging than at precontrast and portal phase imaging (p<0.05), but there was no difference between arterial and delayed imaging. The latter provided better mass delineation than precontrast, arterial and portal phase imaging (p<0.05). While in terms of lesion conspicuity and vascular anatomy, the delayed phase was better than the arterial phase (p<0.05) but similar to the precontrast and portal phase. During the delayed phase, the gradient-echo sequence showed better results than the spin-echo in terms of liver SNR, and lesion SNR and CNR (p<0.05). Because it provides better lesion conspicuity and mass delineation by improving liver SNR and lesion-to-liver CNR, the addition of the delayed phase to a dynamic MRI sequence after gadobenate dimeglumine adminstration facilitates lesion detection. For delayed-phase imaging, the

  17. Gadobenate dimeglumine-enhanced MR of VX2 carcinoma in rabbit liver: usefulness of the delayed phase imaging and optimal pulse sequence

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Seung Il; Lee, Jeong Min; Kim, Young Kon; Kim, Chong Soo [College of Medicine, Chonbuk National Univ., Chonju (Korea, Republic of)

    2002-07-01

    To assess the diagnostic value of delayed imaging using gadobenate dimeglumine (MultiHance) and to determine the optimal pulse sequence for the detection of VX2 carcinoma lesions in the rabbit. Twelve VX2 carcinomas implanted in the livers of eleven New Zealand rabbits were studied. All patients underwent an MR protocal consisting of precontrast T2-and T1-weighted sequences, followed by repetition of the T1-weighted sequence at 0 to 30 (arterial phase). 31-60 (portal phase), and 40 minutes (delayed phase) after the intravenous administration of 0.1 mmol/kg of gadobenate dimeglumine. The signal-to-noise ratio (SNR) of the liver and VX2 tumor, and the lesion-to-liver contrast-to-noise ratio (CNR) of precontrast and postcontrast MR images were quantitatively analyzed, and two experienced radiologists evaluated image quality in terms of lesion conspicuity, artifact, mass delineation, and vascular anatomy. Liver SNR was significantly higher at delayed imaging than at precontrast, arterial, and portal imaging (p<0.05), while lesion SNR was significantly higher at delayed imaging than at precontrast imaging (p<0.05). Lesion CNR was higher at delayed imaging than at precontrast and portal phase imaging (p<0.05), but there was no difference between arterial and delayed imaging. The latter provided better mass delineation than precontrast, arterial and portal phase imaging (p<0.05). While in terms of lesion conspicuity and vascular anatomy, the delayed phase was better than the arterial phase (p<0.05) but similar to the precontrast and portal phase. During the delayed phase, the gradient-echo sequence showed better results than the spin-echo in terms of liver SNR, and lesion SNR and CNR (p<0.05). Because it provides better lesion conspicuity and mass delineation by improving liver SNR and lesion-to-liver CNR, the addition of the delayed phase to a dynamic MRI sequence after gadobenate dimeglumine adminstration facilitates lesion detection. For delayed-phase imaging, the

  18. MEMS Keys as a Way to Delay the Phase of the Microwave Range

    Directory of Open Access Journals (Sweden)

    Anton Antonenko

    2015-04-01

    Full Text Available The paper deals with a new type of phase shifter antennas scanned beam shows the principle of constructing controlled microwave phase shifters that have a low cost. Also, given the results of a theoretical study of the main characteristics of dependency - controlled phase shift and frequency band working on the design parameters and then refined by calculating finite element program CST Microwave Studio. These inexpensive scanned antenna can be used in radar centimeter and millimeter wavelengths in the frequency range 2 ¸ 30 GHz. The results of calculation of capacitive and inductive coupling during switching detector elements and the simulation results of the phase shift in passing through the phase shifter television signal containing includes microelectromechanical systems - manageable sections that have to change the direction of polarization of the signal. Thus for supplying voltage-controlled permanent magnet field is used. According to the simulation results, which are presented in the conclusions can be drawn about the development of the design of optimal geometric parameters, the values obtained for the results of the optimization modeling. However revealed a high quality factor switching phase.

  19. Sex-specific sleep patterns among university students in Lebanon: impact on depression and academic performance.

    Science.gov (United States)

    Kabrita, Colette S; Hajjar-Muça, Theresa A

    2016-01-01

    Good sleep quality and quantity are fundamental to the maintenance of normal physiological processes. Changes in sleep patterns are commonly observed among young adults and are shown to impact neurocognitive, academic, and psychological well-being. Given the scarcity of sleep information about Lebanon and acknowledging the sex differences in various sleep dimensions, we conducted a study that aimed at assessing sex differences in sleep habits among university students in Lebanon in relation to psychoacademic status. A total of 540 students (50.6% females) completed a questionnaire that inquired about sociodemographics and evaluated sleep quality and depression using the Pittsburg Sleep Quality Index (PSQI) and Center for Epidemiological Studies Depression Scale (CES-D), respectively. The mean PSQI global score (6.57±3.49) indicated poor sleep, with no significant differences between men and women. The sleep/wake rhythm was delayed on weekends for both sexes. Females exhibited earlier bedtimes and rise times and longer sleep durations on both weekdays and weekends. However, unlike males females showed a greater phase delay in wake times than bedtimes on weekends (149 minutes vs 74 minutes, respectively). In all, 70.9% of females suffered from depressive symptoms, which was a significantly higher proportion compared with 58.5% of males (Pacademic performance of females was significantly better than that of males (2.8±0.61 vs 2.65±0.61, Psleep duration (r=-0.221, Psleep timing, such as bedtime/rise time and nocturnal sleep duration, rather than sleep quality exist among Lebanese university students. Sex-specific sleep patterns have differential impact on psychological and academic well-being.

  20. Retaining older workers: the effect of phased retirement on delaying early retirement

    Directory of Open Access Journals (Sweden)

    Åsmund Hermansen

    2015-01-01

    Full Text Available Introduction: Phased retirement involves reducing working time in the final years before retirement. The aim of phased retirement is to extend working careers and retain older workers who would otherwise opt for full early retirement. This article investigates the effect of offering phased retirement on early-retirement behaviour in Norway.Method: The data used in the analysis covers the period between 2000 and 2010 and comprises all employees between 61 and 62 years of age (N= 18 174 who were employed in any of the 442 companies that participated in a 2010 survey carried out by the Fafo Institute for Labour and Social Research and Respons Analyse AS, a Norwegian research firm. I use a difference-in-differences approach and logistic regression, which enables the measurement of changes in the individual relative risk of retiring full-time on the contractual pension (AFP, avtalefestet pensjon, contractual early-retirement pension, before and after the introduction of phased retirement as a retention measure.Results: The results show that working in a company that offers reduced working hours for older workers does not have an effect on the relative risk of a 61- or 62-year-old withdrawing a full contractual pension in the next two years of their employment. This result is evident both before and after controlling for a range of known individual risk factors, as well as after controlling for company characteristics.Discussion: In the search for suitable measures for retaining older workers, offering phased retirement may still be part of the answer. Though my analysis does not support the idea that more flexible working hours is a decisive factor for those who choose to opt for full early retirement, a possible next step could be to investigate the impact of offering flexible working hours on the employment duration of those who do remain in employment.

  1. Experimental alveolitis in rats: microbiological, acute phase response and histometric characterization of delayed alveolar healing.

    Science.gov (United States)

    Rodrigues, Moacyr Tadeu Vicente; Cardoso, Camila Lopes; Carvalho, Paulo Sérgio Perri de; Cestari, Tânia Mary; Feres, Magda; Garlet, Gustavo Pompermaier; Ferreira, Osny

    2011-01-01

    The pathogenesis of alveolitis is not well known and therefore experimental situations that mimic some features of this disease should be developed. In this study, the evolution of the experimentally induced infection in rat sockets is characterized, which leads to clinical signs of suppurative alveolitis with remarkable wound healing disturbs. Non-infected (Group I) and experimentally infected sockets in Rattus novergicus (Group II) were histometrically evaluated regarding the kinetics of alveolar healing. In addition, the characterization of the present bacteria in inoculation material and the serum levels of C-reactive protein (CRP) were performed. The detected species were Capnocytophaga ochracea, Fusobacterium nucleatum ss nucleatum, Prevotella melaninogenica, Streptococcus anginosus, Treponema socranskii and Streptococcus sanguis. All experimentally infected rats developed suppurative alveolitis, showing higher levels of CRP in comparison to those non-infected ones. Furthermore, infected rats presented a significant delayed wound healing as measured by the histometric analysis (higher persistent polymorphonuclear infiltrate and lower density of newly formed bone). These findings indicate that rat sockets with experimentally induced infection produced higher levels of serum CRP, showing the potential of disseminated infection and a disturb in the alveolar repair process in an interesting experimental model for alveolitis studies.

  2. Sleep wake pattern analysis: Study of 131 medical students

    OpenAIRE

    Nita Ninama; Jaydeep Kangathara

    2012-01-01

    Objective:Sleep is part of the rhythm of life. Without a good sleep the mind is less adapts, mood is altered and the body loses the ability to refresh. The sleep wake cycle of the students is quite different and characterized by delayed onset, partial sleep deprivation, poor sleep quality, insufficient sleep duration and occurrence of napping episodes during the day The aim of the present study is to know sleep wake pattern in medical student, role of residence and individual characterization...

  3. Residual sleep disturbance and risk of relapse during the continuation/maintenance phase treatment of major depressive disorder with the selective serotonin reuptake inhibitor fluoxetine

    Directory of Open Access Journals (Sweden)

    McGrath Patrick J

    2010-02-01

    Full Text Available Abstract Background Relapse of major depressive disorder (MDD is a common clinical problem. This study was designed to determine whether residual sleep disturbance (insomnia and hypersomnia predict risk of relapse during the continuation and maintenance treatment of MDD. Methods A total of 570 patients with MDD were treated with open-label, flexible dose fluoxetine (range 20 to 60 mg; mean dose = 45.8 mg/day; SD = 15.1 for 12 weeks. Under double blind conditions, 262 patients who achieved clinical response were randomly assigned to continue fluoxetine or to switch to placebo for 52 weeks or until relapse. Residual sleep disturbance during the baseline visit of the double-blind phase was assessed using items 4, 5, 6 (insomnia and 22, 23, 24 (hypersomnia of the Hamilton Depression Rating Scale (HDRS. Survival analysis was utilized to determine the effect of residual sleep disturbance on risk of relapse. Results The severities of early (P > 0.05, middle (P > 0.05, late (P > 0.05, or total (P > 0.05 residual insomnia were not found to significantly predict risk of relapse during continuation and maintenance-phase treatment. Similarly, the severities of early bedtime (P > 0.05, oversleeping (P > 0.05, napping (P > 0.05, or total (P > 0.05 residual hypersomnia were not found to significantly predict risk of relapse during continuation and maintenance-phase treatment. Conclusion The present study did not identify the severity of residual sleep disturbance among fluoxetine responders to predict risk of MDD relapse. The size of our sample may have precluded us from identifying more modest effects of residual sleep disturbance on the risk of relapse in MDD patients. Future studies are needed to further explore the relationship between residual sleep disturbance and relapse in MDD. Trial Registration ClinicalTrials.gov Identifier: NCT00427128

  4. An analytical method for PID controller tuning with specified gain and phase margins for integral plus time delay processes.

    Science.gov (United States)

    Hu, Wuhua; Xiao, Gaoxi; Li, Xiumin

    2011-04-01

    In this paper, an analytical method is proposed for proportional-integral/proportional-derivative/proportional-integral-derivative (PI/PD/PID) controller tuning with specified gain and phase margins (GPMs) for integral plus time delay (IPTD) processes. Explicit formulas are also obtained for estimating the GPMs resulting from given PI/PD/PID controllers. The proposed method indicates a general form of the PID parameters and unifies a large number of existing rules as PI/PD/PID controller tuning with various GPM specifications. The GPMs realized by existing PID tuning rules are computed and documented as a reference for control engineers to tune the PID controllers. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

  5. Zebularine exerts its antiproliferative activity through S phase delay and cell death in human malignant mesothelioma cells.

    Science.gov (United States)

    Takemura, Yukitoshi; Satoh, Motohiko; Hatanaka, Kenichi; Kubota, Shunichiro

    2018-04-24

    Malignant mesothelioma is an asbestos-related aggressive tumor and current therapy remains ineffective. Zebularine as a DNA methyltransferase (DNMT) inhibitor has an anti-tumor effect in several human cancer cells. The aim of the present study was to investigate whether zebularine could induce antiproliferative effect in human malignant mesothelioma cells. Zebularine induced cell growth inhibition in a dose-dependent manner. In addition, zebularine dose-dependently decreased expression of DNMT1 in all malignant mesothelioma cells tested. Cell cycle analysis indicated that zebularine induced S phase delay. Zebularine also induced cell death in malignant mesothelioma cells. In contrast, zebularine did not induce cell growth inhibition and cell death in human normal fibroblast cells. These results suggest that zebularine has a potential for the treatment of malignant mesothelioma by inhibiting cell growth and inducing cell death.

  6. The Neuroprotective Aspects of Sleep.

    Science.gov (United States)

    Eugene, Andy R; Masiak, Jolanta

    2015-03-01

    Sleep is an important component of human life, yet many people do not understand the relationship between the brain and the process of sleeping. Sleep has been proven to improve memory recall, regulate metabolism, and reduce mental fatigue. A minimum of 7 hours of daily sleep seems to be necessary for proper cognitive and behavioral function. The emotional and mental handicaps associated with chronic sleep loss as well as the highly hazardous situations which can be contributed to the lack of sleep is a serious concern that people need to be aware of. When one sleeps, the brain reorganizes and recharges itself, and removes toxic waste byproducts which have accumulated throughout the day. This evidence demonstrates that sleeping can clear the brain and help maintain its normal functioning. Multiple studies have been done to determine the effects of total sleep deprivation; more recently some have been conducted to show the effects of sleep restriction, which is a much more common occurrence, have the same effects as total sleep deprivation. Each phase of the sleep cycle restores and rejuvenates the brain for optimal function. When sleep is deprived, the active process of the glymphatic system does not have time to perform that function, so toxins can build up, and the effects will become apparent in cognitive abilities, behavior, and judgment. As a background for this paper we have reviewed literature and research of sleep phases, effects of sleep deprivation, and the glymphatic system of the brain and its restorative effect during the sleep cycle.

  7. The anti-asthmatic drug pranlukast suppresses the delayed-phase vomiting and reverses intracellular indices of emesis evoked by cisplatin in the least shrew (Cryptotis parva).

    Science.gov (United States)

    Darmani, Nissar A; Chebolu, Seetha; Zhong, Weixia; Kim, William D; Narlesky, Matthew; Adams, Joia; Dong, Fanglong

    2017-08-15

    The introduction of second generation serotonin 5-HT 3 receptor (5-HT 3 ) antagonist palonosetron combined with long-acting substance P neurokinin NK 1 receptor (NK 1 ) antagonists (e.g. netupitant) has substantially improved antiemetic therapy against early- and delayed-phases of emesis caused by highly emetogenic chemotherapeutics such as cisplatin. However, the improved efficacy comes at a cost that many patients cannot afford. We introduce a new class of antiemetic, the antiasthmatic leukotriene CysLT1 receptor antagonist pranlukast for the suppression of cisplatin-evoked vomiting. Pranlukast (10mg/kg) by itself significantly reduced the mean frequency of vomits (70%) and fully protected least shrews from vomiting (46%) during the delayed-phase of cisplatin (10mg/kg)-evoked vomiting. Although, pranlukast tended to substantially reduce both the mean frequency of vomits and the number of shrews vomiting during the early-phase, these reductions failed to attain significance. When combined with a first (tropisetron)- or a second (palonosetron)-generation 5-HT 3 receptor antagonist, pranlukast potentiated their antiemetic efficacy during both phases of vomiting. In addition, pranlukast by itself prevented several intracellular signal markers of cisplatin-evoked delayed-vomiting such as phosphorylation of ERK1/2 and PKA. When pranlukast was combined with either palonosetron or tropisetron, these combinations suppressed the evoked phosphorylation of: i) ERK1/2 during both acute- and delayed-phase, ii) PKCα/β at the peak acute-phase, and iii) PKA at the peak delayed-phase. The current and our published findings suggest that overall behavioral and intracellular signaling effects of pranlukast via blockade of CysLT1 receptors generally appear to be similar to the NK 1 receptor antagonist netupitant with some differences. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Sleep Disorders

    Science.gov (United States)

    ... the day, even if you have had enough sleep? You might have a sleep disorder. The most common kinds are Insomnia - a hard time falling or staying asleep Sleep apnea - breathing interruptions during sleep Restless legs syndrome - ...

  9. Sleep Problems

    Science.gov (United States)

    ... For Consumers Consumer Information by Audience For Women Sleep Problems Share Tweet Linkedin Pin it More sharing ... 101 KB) En Español Medicines to Help You Sleep Tips for Better Sleep Basic Facts about Sleep ...

  10. Sleep Habits and Sleep Problems in Healthy Preschoolers.

    Science.gov (United States)

    Murthy, C L Srinivasa; Bharti, Bhavneet; Malhi, Prahbhjot; Khadwal, Alka

    2015-07-01

    To describe the sleep patterns and problems in children aged between 12 and 36 mo of age. This cross sectional survey was collected over a span of 1 y in Advanced Pediatric Centre, PGIMER, Chandigarh and crèches of Chandigarh. Children in the age group of 12 to 36 mo were included in study. Children with chronic illness, developmental delay, seizure disorder and lack of consent were excluded. A total of 368 children were enrolled. Main outcome measures were sleep duration over 1 to 3 y of life; sleep behavior at onset, during and waking of sleep and parent reported sleep problems and their predictors. The average duration of sleep was 12.5 h (S.D = 1.9). The mean total sleep duration and mean day time sleep duration decreased, while mean night time sleep increased as the age advanced from 12 to 36 mo. Following were the frequency of sleep habits seen in the index study; bed time routine was seen only in 68(18.5 %), a regular bed time ritual was seen in 281(76.4 %), 329(89.4 %) children frequently required 0-20 min time to fall asleep, 11(3 %) parents used sleep inducing drugs. Night waking (1 to 3 times a night) was seen in 297(80.7 %) and its frequency declined with age. Parent reported sleep problems were seen in 12.8 % (47/368). Lack of co-sleeping and night waking were considered as strongest predictors of parent reported sleep problems. Toddlers' sleep duration, night waking behavior, and day time naps decrease as the age progress while night time sleep duration increases with age. Lack of co-sleeping and night waking are considered as strongest predictors of parent reported sleep problems.

  11. Sleep and environmental context: interactive effects for memory.

    Science.gov (United States)

    Cairney, Scott A; Durrant, Simon J; Musgrove, Hazel; Lewis, Penelope A

    2011-09-01

    Sleep after learning is often beneficial for memory. Reinstating an environmental context that was present at learning during subsequent retrieval also leads to superior declarative memory performance. This study examined how post-learning sleep, relative to wakefulness, impacts upon context-dependent memory effects. Thirty-two participants encoded word lists in each of two rooms (contexts), which were different in terms of size, odour and background music. Immediately after learning and following a night of sleep or a day of wakefulness, memory for all previously studied words was tested using a category-cued recall task in room one or two alone. Accordingly, a comparison could be made between words retrieved in an environmental context which was the same as, or different to, that of the learning phase. Memory performance was assessed by the difference between the number of words remembered at immediate and delayed retrieval. A 2 × 2 × 2 mixed ANOVA revealed an interaction between retrieval context (same/different to learning) and retention interval (sleep/wakefulness), which was driven by superior memory after sleep than after wake when learning and retrieval took place in different environmental contexts. Our findings suggest a sleep-related reduction in the extent to which context impacts upon retrieval. As such, these data provide initial support for the possibility that sleep dependent processes may promote a decontextualisation of recently formed declarative representations.

  12. Sleep to implement an intention.

    Science.gov (United States)

    Diekelmann, Susanne; Wilhelm, Ines; Wagner, Ullrich; Born, Jan

    2013-01-01

    Sleep supports the consolidation of new memories. However, this effect has mainly been shown for memories of past events. Here we investigated the role of sleep for the implementation of intentions for the future. Subjects were instructed on a plan that had to be executed after a delay of 2 days. After plan instruction, subjects were either allowed to sleep or stayed awake for one night (Exp. 1) or had a 3-h sleep period either during the early night (SWS-rich sleep) or late night (REM-rich sleep; Exp. 2). In both experiments, retesting took place 2 days later after one recovery night. Sleep laboratory. A total of 56 healthy young adults participated in the study. N/A. All of the subjects who were allowed to sleep after plan instruction executed the intention 2 days later, whereas only 61% of wake subjects did so (P = 0.004; Exp. 1). Also after early SWS-rich sleep all of the subjects remembered to execute the intention, but only 55% did so after late REM-rich sleep (P = 0.015; Exp. 2). Sleep, especially SWS, plays an important role for the successful implementation of delayed intentions.

  13. Circadian Rhythm and Sleep During Prolonged Antarctic Residence at Chinese Zhongshan Station.

    Science.gov (United States)

    Chen, Nan; Wu, Quan; Xiong, Yanlei; Chen, Guang; Song, Dandan; Xu, Chengli

    2016-12-01

    Residence at Zhongshan Station (69°22'24″S, 76°22'40″E) for over 1 year exposes winter-over members to marked changes of light-dark cycle, ranging from the constant daylight of polar days to the constant darkness of polar nights, in addition to geographic and social isolation. This extreme photoperiodic environment may increase the risk of sleep disturbances and circadian desynchrony. The aim of this study was to investigate the circadian rhythm and sleep phase of Chinese winter-over expeditioners at Zhongshan Station. This study was conducted on 17 healthy male participants before departure from Shanghai and during residence at Zhongshan Station for 1 year (before winter, mid-winter, and end of winter). Sequential urine samples over 48 hours were obtained, 6-sulphatoxymelatonin in urine was assessed, and the circadian rhythm was analyzed by a cosine curve-fitting method. Participants' sleep parameters were obtained from wrist actigraphy and sleep logs. Morningness-Eveningness Questionnaire and Seasonal Pattern Assessment Questionnaire were completed. The acrophase of 6-sulphatoxymelatonin rhythm, sleep onset, sleep offset, and mid-sleep time were delayed significantly (P circadian rhythm and sleep phase, later chronotype, and incidence of subsyndromal seasonal affective disorder. An appropriate combination of artificial bright light during dark winter months and a strict social schedule are recommended in a winter-over station in Antarctica. Copyright © 2016 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

  14. Sleep can eliminate list-method directed forgetting.

    Science.gov (United States)

    Abel, Magdalena; Bäuml, Karl-Heinz T

    2013-05-01

    Recent work suggests a link between sleep and memory consolidation, indicating that sleep in comparison to wakefulness stabilizes memories. However, relatively little is known about how sleep affects forgetting. Here we examined whether sleep influences directed forgetting, the finding that people can intentionally forget obsolete memories when cued to do so. We applied the list-method directed forgetting task and assessed memory performance after 3 delay intervals. Directed forgetting was present after a short 20-min delay and after a 12-hr delay filled with diurnal wakefulness; in contrast, the forgetting was absent after a 12-hr delay that included regular nocturnal sleep. Successful directed forgetting after a delay thus can depend on whether sleep or wakefulness follows upon encoding: When wakefulness follows upon encoding, the forgetting can be successful; when sleep follows upon encoding, no forgetting may arise. Connections of the results to recent studies on the interplay between forgetting and sleep are discussed.

  15. Meeting Teen Sleep Needs Creatively

    Science.gov (United States)

    Wolfson, Amy R.; Carskadon, Mary A.

    2005-01-01

    Research on the sleep needs of adolescents and the influence of sleep on learning and behavior have captured the interest of school districts nationwide and in other countries as well. As a result, school officials are being urged to acknowledge the evidence and to adjust school schedules accordingly (e.g., to delay high school start times). The…

  16. Sleep in trigeminal autonomic cephalagias

    DEFF Research Database (Denmark)

    Barløse, Mads; Lund, Nunu; Jensen, Rigmor Højland

    2014-01-01

    and eventually to more effective therapeutic regimens. This review aims to evaluate the existing literature on the subject of TACs and sleep. An association between episodic CH and distinct macrostructural sleep phases, especially the relation to rapid eye movement (REM) sleep, has been described in some older...... studies but could not be confirmed in other, more recent studies. Investigations into the microstructure of sleep in these patients are lacking. Only a few case reports exist on the relation between sleep and other TACs. SUMMARY: Recent studies do not find an association between CH and REM sleep. One...... older study suggests chronic paroxysmal hemicranias may be locked to REM sleep but otherwise the relation is unknown. Reports indicate that CH and obstructive sleep apnoea are associated in some individuals but results are diverging. Single cases show improvement of CH upon treatment of sleep apnoea...

  17. Performance enhancement of the single-phase series active filter by employing the load voltage waveform reconstruction and line current sampling delay reduction methods

    DEFF Research Database (Denmark)

    Senturk, O.S.; Hava, A.M.

    2011-01-01

    This paper proposes the waveform reconstruction method (WRM), which is utilized in the single-phase series active filter's (SAF's) control algorithm, in order to extract the load harmonic voltage component of voltage harmonic type single-phase diode rectifier loads. Employing WRM and the line...... current sampling delay reduction method, a single-phase SAF compensated system provides higher harmonic isolation performance and higher stability margins compared to the system using conventional synchronous-reference-frame-based methods. The analytical, simulation, and experimental studies of a 2.5 k...

  18. Utility of bolus dynamic CT for the detection of hypervascular malignant hepatic tumors. Mainly referring to the comparison with delayed phase contrast-enhanced CT

    International Nuclear Information System (INIS)

    Matsuda, Hiromichi; Abe, Kimihiko; Freeny, P.C.

    1996-01-01

    In order to analyze the usefulness of dynamic contrast-enhanced CT, 84 patients who had hepatocellular carcinoma or suspected hypervascular metastases were studied with conventional incremental dynamic CT (CID-CT) or double helical CT (DH-CT). Delayed phase contrast-enhanced CT studies were consecutively performed in all patients. Thirty-six of 84 patients had malignant hepatic neoplasms; six had hepatocellular carcinoma and 30 had metastatic tumors. At first, the detectability of hepatic lesions was evaluated with bolus dynamic CT and delayed phase CT. Dynamic CT has detected more lesions than delayed CT. Some hepatic lesions described as isodensity were missed on CID-CT. Therefore, delayed phase CT cannot be eliminated when CID-CT is performed. Secondly, hepatic lesion detectability with CID-CT was compared with that of DH-CT. DH-CT did not miss the hepatic lesions picked up by delayed phase CT and was expected to provide excellent detectability of hypervascular hepatic neoplasms. In addition, first helical CT showed most hepatic lesions as areas of obvious hyperdensity, while CID-CT did not show their correct vascularities. So-called hypervascular hepatic tumors, however, were not always hypervascular and were demonstrated as areas of iso-hypodensity even on initial helical scanning. Second helical CT was useful to detect these so-called hypervascular, but actually hypovascular lesions. In conclusion, dynamic CT was helpful in detecting hypervascular hepatic malignant neoplasms, and DH-CT was more accurate than-CID-CT for the detection of hepatic lesions and the evaluation of vascular lesion. (author)

  19. BDNF in sleep, insomnia, and sleep deprivation.

    Science.gov (United States)

    Schmitt, Karen; Holsboer-Trachsler, Edith; Eckert, Anne

    2016-01-01

    The protein brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family of growth factors involved in plasticity of neurons in several brain regions. There are numerous evidence that BDNF expression is decreased by experiencing psychological stress and that, accordingly, a lack of neurotrophic support causes major depression. Furthermore, disruption in sleep homeostatic processes results in higher stress vulnerability and is often associated with stress-related mental disorders. Recently, we reported, for the first time, a relationship between BDNF and insomnia and sleep deprivation (SD). Using a biphasic stress model as explanation approach, we discuss here the hypothesis that chronic stress might induce a deregulation of the hypothalamic-pituitary-adrenal system. In the long-term it leads to sleep disturbance and depression as well as decreased BDNF levels, whereas acute stress like SD can be used as therapeutic intervention in some insomniac or depressed patients as compensatory process to normalize BDNF levels. Indeed, partial SD (PSD) induced a fast increase in BDNF serum levels within hours after PSD which is similar to effects seen after ketamine infusion, another fast-acting antidepressant intervention, while traditional antidepressants are characterized by a major delay until treatment response as well as delayed BDNF level increase. Key messages Brain-derived neurotrophic factor (BDNF) plays a key role in the pathophysiology of stress-related mood disorders. The interplay of stress and sleep impacts on BDNF level. Partial sleep deprivation (PSD) shows a fast action on BDNF level increase.

  20. Sleep Disorders

    DEFF Research Database (Denmark)

    Rahbek Kornum, Birgitte; Mignot, Emmanuel

    2014-01-01

    mediates circadian regulation of sleep. Misalignment with the rhythm of the sun results in circadian disorders and jet lag. The molecular basis of homeostatic sleep regulation is mostly unknown. A network of mutually inhibitory brain nuclei regulates sleep states and sleep-wake transitions. Abnormalities...... in these networks create sleep disorders, including rapid eye movement sleep behavior disorder, sleep walking, and narcolepsy. Physiological changes associated with sleep can be imbalanced, resulting in excess movements such as periodic leg movements during sleep or abnormal breathing in obstructive sleep apneas....... As every organ in the body is affected by sleep directly or indirectly, sleep and sleep-associated disorders are frequent and only now starting to be understood....

  1. Obstructive Sleep Apnea

    Science.gov (United States)

    ... These disruptions impair your ability to reach the desired deep, restful phases of sleep, and you'll ... of memory problems, morning headaches, mood swings or feelings of depression, and a need to urinate frequently ...

  2. Descartes and His Peculiar Sleep Pattern.

    Science.gov (United States)

    Damjanovic, Aleksandar; Milovanovic, Srdjan D; Trajanovic, Nikola N

    2015-01-01

    Rene Descartes (1596-1650) was a mathematician, philosopher, and scholar, whose work set a foundation for modern science. Among other interests, he focused on locating the "core and the seat of the soul" and concluded that the pineal gland was such a structure. Recent scientific findings validate Descartes' deep interest in pineal gland, appreciating its role as part of the circadian rhythm system. On the other hand, the biographical information suggests that Descartes had an aberration of the circadian rhythm (delayed sleep phase). Coincidentally, this meant that one of the most important things in his private life and one of the most significant areas of his research intersected in an overlooked way.

  3. Effect of Oral Contraceptives, Menstrual Phase and Conditions on Alertness, Performance, and Rhythms in Sleep Deprived Women

    National Research Council Canada - National Science Library

    Badia, Pietro

    1996-01-01

    During our first year of funding, we tested the effects of caffeine, bright light, and placebo treatments on alertness, performance, mood, melatonin, and body temperature during 48 hr of sleep deprivation...

  4. Sleep patterns in high school and university students: a longitudinal study.

    Science.gov (United States)

    Urner, Martin; Tornic, Jure; Bloch, Konrad E

    2009-08-01

    We performed a longitudinal study to investigate whether changes in social zeitgebers and age alter sleep patterns in students during the transition from high school to university. Actimetry was performed on 24 high-school students (mean age+/-SD: 18.4+/-0.9 yrs; 12 females) for two weeks. Recordings were repeated in the same subjects 5 yrs later when they were university students. The sleep period duration and its center, the mid-sleep time, and total sleep time were estimated by actimetry. Actigraphic total sleep time was similar when in high school and at the university on school days (6.31+/-0.47 vs. 6.45+/-0.80 h, p = ns) and longer on leisure days by 1.10+/-1.10 h (p school days) when in high school, but not at the university. Compared to the high school situation, the mid-sleep time was delayed when at the university on school days (03:11+/-0.6 vs. 03:55+/-0.7 h, p sleep times on school and leisure days when in high school were significantly correlated with the corresponding values 5 yrs later when at the university (r = 0.58 and r = 0.55, p sleep time between school and leisure days when students attended high school and the delayed mid-sleep time on school days when students attended university are consistent with a circadian phase shift due to changes in class schedules, other zeitgebers, and lifestyle preferences. Age-related changes may also have occurred, although some individuality of the sleep pattern was maintained during the 5 yr study span. These findings have important implications for optimizing school and work schedules in students of different age and level of education.

  5. Differential sleep, sleepiness, and neurophysiology in the insomnia phenotypes of shift work disorder.

    Science.gov (United States)

    Gumenyuk, Valentina; Belcher, Ren; Drake, Christopher L; Roth, Thomas

    2015-01-01

    To characterize and compare insomnia symptoms within two common phenotypes of Shift Work Disorder. Observational laboratory and field study. Hospital sleep center. 34 permanent night workers. Subjects were classified by Epworth Sleepiness Scale and Insomnia Severity Index into 3 subgroups: asymptomatic controls, alert insomniacs (AI), and sleepy insomniacs (SI). Sleep parameters were assessed by sleep diary. Circadian phase was evaluated by dim-light salivary melatonin onset (DLMO). Objective sleepiness was measured using the multiple sleep latency test (MSLT). Brain activity was measured using the N1 event-related potential (ERP). A tandem repeat in PER3 was genotyped from saliva DNA. (1) AI group showed normal MSLT scores but elevated N1 amplitudes indicating cortical hyperarousal. (2) SI group showed pathologically low MSLT scores but normal N1 amplitudes. (3) AI and SI groups were not significantly different from one another in circadian phase, while controls were significantly phase-delayed relative to both SWD groups. (4) AI showed significantly longer sleep latencies and lower sleep efficiency than controls during both nocturnal and diurnal sleep. SI significantly differed from controls in nocturnal sleep parameters, but differences during diurnal sleep periods were smaller and not statistically significant. (5) Genotype × phenotype χ² analysis showed significant differences in the PER3 VNTR: 9 of 10 shift workers reporting sleepiness in a post hoc genetic substudy were found to carry the long tandem repeat on PER3, while 4 of 14 shift workers without excessive sleepiness carried the long allele. Our results suggest that the sleepy insomnia phenotype is comprehensively explained by circadian misalignment, while the alert insomnia phenotype resembles an insomnia disorder precipitated by shift work. © 2014 Associated Professional Sleep Societies, LLC.

  6. Sleep Deprivation and Caffeine Treatment Potentiate Photic Resetting of the Master Circadian Clock in a Diurnal Rodent.

    Science.gov (United States)

    Jha, Pawan Kumar; Bouâouda, Hanan; Gourmelen, Sylviane; Dumont, Stephanie; Fuchs, Fanny; Goumon, Yannick; Bourgin, Patrice; Kalsbeek, Andries; Challet, Etienne

    2017-04-19

    Circadian rhythms in nocturnal and diurnal mammals are primarily synchronized to local time by the light/dark cycle. However, nonphotic factors, such as behavioral arousal and metabolic cues, can also phase shift the master clock in the suprachiasmatic nuclei (SCNs) and/or reduce the synchronizing effects of light in nocturnal rodents. In diurnal rodents, the role of arousal or insufficient sleep in these functions is still poorly understood. In the present study, diurnal Sudanian grass rats, Arvicanthis ansorgei , were aroused at night by sleep deprivation (gentle handling) or caffeine treatment that both prevented sleep. Phase shifts of locomotor activity were analyzed in grass rats transferred from a light/dark cycle to constant darkness and aroused in early night or late night. Early night, but not late night, sleep deprivation induced a significant phase shift. Caffeine on its own induced no phase shifts. Both sleep deprivation and caffeine treatment potentiated light-induced phase delays and phase advances in response to a 30 min light pulse, respectively. Sleep deprivation in early night, but not late night, potentiated light-induced c-Fos expression in the ventral SCN. Caffeine treatment in midnight triggered c-Fos expression in dorsal SCN. Both sleep deprivation and caffeine treatment potentiated light-induced c-Fos expression in calbindin-containing cells of the ventral SCN in early and late night. These findings indicate that, in contrast to nocturnal rodents, behavioral arousal induced either by sleep deprivation or caffeine during the sleeping period potentiates light resetting of the master circadian clock in diurnal rodents, and activation of calbindin-containing suprachiasmatic cells may be involved in this effect. SIGNIFICANCE STATEMENT Arousing stimuli have the ability to regulate circadian rhythms in mammals. Behavioral arousal in the sleeping period phase shifts the master clock in the suprachiasmatic nuclei and/or slows down the photic

  7. Long-term memory, sleep, and the spacing effect.

    Science.gov (United States)

    Bell, Matthew C; Kawadri, Nader; Simone, Patricia M; Wiseheart, Melody

    2014-01-01

    Many studies have shown that memory is enhanced when study sessions are spaced apart rather than massed. This spacing effect has been shown to have a lasting benefit to long-term memory when the study phase session follows the encoding session by 24 hours. Using a spacing paradigm we examined the impact of sleep and spacing gaps on long-term declarative memory for Swahili-English word pairs by including four spacing delay gaps (massed, 12 hours same-day, 12 hours overnight, and 24 hours). Results showed that a 12-hour spacing gap that includes sleep promotes long-term memory retention similar to the 24-hour gap. The findings support the importance of sleep to the long-term benefit of the spacing effect.

  8. Rapid eye movement sleep disturbances in Huntington disease

    DEFF Research Database (Denmark)

    Arnulf, I.; Nielsen, J.; Lohmann, E.

    2008-01-01

    and shortened rapid eye movement (REM) sleep, and increased periodic leg movements. Three HD patients (12%) had REM sleep behavior disorders. No sleep abnormality correlated with CAG repeat length. Reduced REM sleep duration (but not REM sleep behavior disorders) was present in premanifest carriers and patients...... with very mild HD and worsened with disease severity. In contrast to narcoleptic patients, HD patients had no cataplexy, hypnagogic hallucinations, or sleep paralysis. Four HD patients had abnormally low (sleep latencies, but none had multiple sleep-onset REM periods. Conclusions......: The sleep phenotype of HD includes insomnia, advanced sleep phase, periodic leg movements, REM sleep behavior disorders, and reduced REM sleep but not narcolepsy. Reduced REM sleep may precede chorea. Mutant huntingtin may exert an effect on REM sleep and motor control during sleep Udgivelsesdato: 2008/4...

  9. Integrated High-Speed Digital Optical True-Time-Delay Modules for Synthetic Aperture Radars, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Crystal Research, Inc. proposes an integrated high-speed digital optical true-time-delay module for advanced synthetic aperture radars. The unique feature of this...

  10. Sleep Quiz

    Science.gov (United States)

    Skip Navigation Bar Home Current Issue Past Issues Sleep Quiz Past Issues / Summer 2007 Table of Contents ... on. Photo: iStock Take the National Center on Sleep Disorders Research Sleep Quiz TRUE OR FALSE ? _____1. ...

  11. Sex-specific sleep patterns among university students in Lebanon: impact on depression and academic performance

    Directory of Open Access Journals (Sweden)

    Kabrita CS

    2016-06-01

    Full Text Available Colette S Kabrita,1 Theresa A Hajjar-Muça,2 1Department of Sciences, 2Department of Mathematics and Statistics, Faculty of Natural and Applied Sciences, Notre Dame University – Louaize, Zouk Mosbeh, Lebanon Abstract: Good sleep quality and quantity are fundamental to the maintenance of normal physiological processes. Changes in sleep patterns are commonly observed among young adults and are shown to impact neurocognitive, academic, and psychological well-being. Given the scarcity of sleep information about Lebanon and acknowledging the sex differences in various sleep dimensions, we conducted a study that aimed at assessing sex differences in sleep habits among university students in Lebanon in relation to psychoacademic status. A total of 540 students (50.6% females completed a questionnaire that inquired about sociodemographics and evaluated sleep quality and depression using the Pittsburg Sleep Quality Index (PSQI and Center for Epidemiological Studies Depression Scale (CES-D, respectively. The mean PSQI global score (6.57±3.49 indicated poor sleep, with no significant differences between men and women. The sleep/wake rhythm was delayed on weekends for both sexes. Females exhibited earlier bedtimes and rise times and longer sleep durations on both weekdays and weekends. However, unlike males females showed a greater phase delay in wake times than bedtimes on weekends (149 minutes vs 74 minutes, respectively. In all, 70.9% of females suffered from depressive symptoms, which was a significantly higher proportion compared with 58.5% of males (P<0.01. Based on the mean cumulative self-reported grade point average (GPA, the academic performance of females was significantly better than that of males (2.8±0.61 vs 2.65±0.61, P<0.05, respectively. Depression, as scored by CES-D, in females was significantly negatively correlated with the cumulative GPA (r=-0.278, P<0.01, earlier wake time (r=-0.168, P<0.05, and average sleep duration (r=-0

  12. Benefits of Sleep Extension on Sustained Attention and Sleep Pressure Before and During Total Sleep Deprivation and Recovery.

    Science.gov (United States)

    Arnal, Pierrick J; Sauvet, Fabien; Leger, Damien; van Beers, Pascal; Bayon, Virginie; Bougard, Clément; Rabat, Arnaud; Millet, Guillaume Y; Chennaoui, Mounir

    2015-12-01

    To investigate the effects of 6 nights of sleep extension on sustained attention and sleep pressure before and during total sleep deprivation and after a subsequent recovery sleep. Subjects participated in two experimental conditions (randomized cross-over design): extended sleep (EXT, 9.8 ± 0.1 h (mean ± SE) time in bed) and habitual sleep (HAB, 8.2 ± 0.1 h time in bed). In each condition, subjects performed two consecutive phases: (1) 6 nights of either EXT or HAB (2) three days in-laboratory: baseline, total sleep deprivation and after 10 h of recovery sleep. Residential sleep extension and sleep performance laboratory (continuous polysomnographic recording). 14 healthy men (age range: 26-37 years). EXT vs. HAB sleep durations prior to total sleep deprivation. Total sleep time and duration of all sleep stages during the 6 nights were significantly higher in EXT than HAB. EXT improved psychomotor vigilance task performance (PVT, both fewer lapses and faster speed) and reduced sleep pressure as evidenced by longer multiple sleep latencies (MSLT) at baseline compared to HAB. EXT limited PVT lapses and the number of involuntary microsleeps during total sleep deprivation. Differences in PVT lapses and speed and MSLT at baseline were maintained after one night of recovery sleep. Six nights of extended sleep improve sustained attention and reduce sleep pressure. Sleep extension also protects against psychomotor vigilance task lapses and microsleep degradation during total sleep deprivation. These beneficial effects persist after one night of recovery sleep. © 2015 Associated Professional Sleep Societies, LLC.

  13. Melanopsin as a sleep modulator: circadian gating of the direct effects of light on sleep and altered sleep homeostasis in Opn4(-/- mice.

    Directory of Open Access Journals (Sweden)

    Jessica W Tsai

    2009-06-01

    Full Text Available Light influences sleep and alertness either indirectly through a well-characterized circadian pathway or directly through yet poorly understood mechanisms. Melanopsin (Opn4 is a retinal photopigment crucial for conveying nonvisual light information to the brain. Through extensive characterization of sleep and the electrocorticogram (ECoG in melanopsin-deficient (Opn4(-/- mice under various light-dark (LD schedules, we assessed the role of melanopsin in mediating the effects of light on sleep and ECoG activity. In control mice, a light pulse given during the habitual dark period readily induced sleep, whereas a dark pulse given during the habitual light period induced waking with pronounced theta (7-10 Hz and gamma (40-70 Hz activity, the ECoG correlates of alertness. In contrast, light failed to induce sleep in Opn4(-/- mice, and the dark-pulse-induced increase in theta and gamma activity was delayed. A 24-h recording under a LD 1-hratio1-h schedule revealed that the failure to respond to light in Opn4(-/- mice was restricted to the subjective dark period. Light induced c-Fos immunoreactivity in the suprachiasmatic nuclei (SCN and in sleep-active ventrolateral preoptic (VLPO neurons was importantly reduced in Opn4(-/- mice, implicating both sleep-regulatory structures in the melanopsin-mediated effects of light. In addition to these acute light effects, Opn4(-/- mice slept 1 h less during the 12-h light period of a LD 12ratio12 schedule owing to a lengthening of waking bouts. Despite this reduction in sleep time, ECoG delta power, a marker of sleep need, was decreased in Opn4(-/- mice for most of the (subjective dark period. Delta power reached after a 6-h sleep deprivation was similarly reduced in Opn4(-/- mice. In mice, melanopsin's contribution to the direct effects of light on sleep is limited to the dark or active period, suggesting that at this circadian phase, melanopsin compensates for circadian variations in the photo sensitivity of

  14. Sleep deprivation: consequences for students.

    Science.gov (United States)

    Marhefka, Julie King

    2011-09-01

    During the adolescent years, a delayed pattern of the sleep-wake cycle occurs. Many parents and health care providers are not aware that once established, these poor sleep habits can continue into adulthood. Early school hours start a pattern of sleep loss that begins a cycle of daytime sleepiness, which may affect mood, behavior, and increase risk for accidents or injury. These sleep-deprived habits established in adolescence can often lead to problems during college years. Sleep hygiene can be initiated to help break the cycle, along with education and implementation of a strict regimen. Monitoring all adolescents and college-aged students for sleep insufficiency is imperative to improve both academic and emotional well-being. Copyright 2011, SLACK Incorporated.

  15. Circadian Rhythm Sleep Disorders

    Directory of Open Access Journals (Sweden)

    Erhan Akinci

    2016-06-01

    Full Text Available The circadian rhythm sleep disorders define the clinical conditions where sleep and ndash;wake rhythm is disrupted despite optimum environmental and social conditions. They occur as a result of the changes in endogenous circadian hours or non-compatibility of environmental factors or social life with endogenous circadian rhythm. The sleep and ndash;wake rhythm is disrupted continuously or in repeating phases depending on lack of balance between internal and external cycles. This condition leads to functional impairments which cause insomnia, excessive sleepiness or both in people. Application of detailed sleep anamnesis and sleep diary with actigraphy record, if possible, will be sufficient for diagnosis. The treatment aims to align endogenous circadian rhythm with environmental conditions. The purpose of this article is to review pathology, clinical characteristics, diagnosis and treatment of circadian rhythm disorder. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2016; 8(2: 178-189

  16. Adjustment of sleep and the circadian temperature rhythm after flights across nine time zones

    Science.gov (United States)

    Gander, Philippa H.; Myhre, Grete; Graeber, R. Curtis; Lauber, John K.; Andersen, Harald T.

    1989-01-01

    The adjustment of sleep-wake patterns and the circadian temperature rhythm was monitored in nine Royal Norwegian Airforce volunteers operating P-3 aircraft during a westward training deployment across nine time zones. Subjects recorded all sleep and nap times, rated nightly sleep quality, and completed personality inventories. Rectal temperature, heart rate, and wrist activity were continuously monitored. Adjustment was slower after the return eastward flight than after the outbound westward flight. The eastward flight produced slower readjustment of sleep timing to local time and greater interindividual variability in the patterns of adjustment of sleep and temperature. One subject apparently exhibited resynchronization by partition, with the temperature rhythm undergoing the reciprocal 15-h delay. In contrast, average heart rates during sleep were significantly elevated only after westward flight. Interindividual differences in adjustment of the temperature rhythm were correlated with some of the personality measures. Larger phase delays in the overall temperature waveform (as measured on the 5th day after westward flight) were exhibited by extraverts, and less consistently by evening types.

  17. Sleep Quality Changes during Overwintering at the German Antarctic Stations Neumayer II and III: The Gender Factor.

    Directory of Open Access Journals (Sweden)

    Mathias Steinach

    Full Text Available Antarctic residence holds many challenges to human physiology, like increased psycho-social tension and altered circadian rhythm, known to influence sleep. We assessed changes in sleep patterns during 13 months of overwintering at the German Stations Neumayer II and III from 2008 to 2014, with focus on gender, as many previous investigations were inconclusive regarding gender-based differences or had only included men.Time in bed, sleep time, sleep efficiency, number of arousals, sleep latency, sleep onset, sleep offset, and physical activity level were determined twice per month during seven overwintering campaigns of n = 54 participants (37 male, 17 female using actimetry. Data were analyzed using polynomial regression and analysis of covariance for change over time with the covariates gender, inhabited station, overwintering season and influence of physical activity and local sunshine radiation.We found overall longer times in bed (p = 0.004 and sleep time (p = 0.014 for women. The covariate gender had a significant influence on time in bed (p<0.001, sleep time (p<0.001, number of arousals (p = 0.04, sleep latency (p = 0.04, and sleep onset (p<0.001. Women separately (p = 0.02, but not men (p = 0.165, showed a linear increase in number of arousals. Physical activity decreased over overwintering time for men (p = 0.003, but not for women (p = 0.174. The decline in local sunshine radiation led to a 48 minutes longer time in bed (p<0.001, 3.8% lower sleep efficiency (p<0.001, a delay of 32 minutes in sleep onset (p<0.001, a delay of 54 minutes in sleep offset (p<0.001, and 11% less daily energy expenditure (p<0.001, for all participants in reaction to the Antarctic winter's darkness-phase.Overwinterings at the Stations Neumayer II and III are associated with significant changes in sleep patterns, with dependences from overwintering time and local sunshine radiation. Gender appears to be an influence, as women showed a declining sleep quality

  18. Sleep Quality Changes during Overwintering at the German Antarctic Stations Neumayer II and III: The Gender Factor.

    Science.gov (United States)

    Steinach, Mathias; Kohlberg, Eberhard; Maggioni, Martina Anna; Mendt, Stefan; Opatz, Oliver; Stahn, Alexander; Gunga, Hanns-Christian

    2016-01-01

    Antarctic residence holds many challenges to human physiology, like increased psycho-social tension and altered circadian rhythm, known to influence sleep. We assessed changes in sleep patterns during 13 months of overwintering at the German Stations Neumayer II and III from 2008 to 2014, with focus on gender, as many previous investigations were inconclusive regarding gender-based differences or had only included men. Time in bed, sleep time, sleep efficiency, number of arousals, sleep latency, sleep onset, sleep offset, and physical activity level were determined twice per month during seven overwintering campaigns of n = 54 participants (37 male, 17 female) using actimetry. Data were analyzed using polynomial regression and analysis of covariance for change over time with the covariates gender, inhabited station, overwintering season and influence of physical activity and local sunshine radiation. We found overall longer times in bed (p = 0.004) and sleep time (p = 0.014) for women. The covariate gender had a significant influence on time in bed (p<0.001), sleep time (p<0.001), number of arousals (p = 0.04), sleep latency (p = 0.04), and sleep onset (p<0.001). Women separately (p = 0.02), but not men (p = 0.165), showed a linear increase in number of arousals. Physical activity decreased over overwintering time for men (p = 0.003), but not for women (p = 0.174). The decline in local sunshine radiation led to a 48 minutes longer time in bed (p<0.001), 3.8% lower sleep efficiency (p<0.001), a delay of 32 minutes in sleep onset (p<0.001), a delay of 54 minutes in sleep offset (p<0.001), and 11% less daily energy expenditure (p<0.001), for all participants in reaction to the Antarctic winter's darkness-phase. Overwinterings at the Stations Neumayer II and III are associated with significant changes in sleep patterns, with dependences from overwintering time and local sunshine radiation. Gender appears to be an influence, as women showed a declining sleep quality

  19. Sleep education with self-help treatment and sleep health promotion for mental and physical wellness in Japan

    OpenAIRE

    Tanaka, Hideki; Tamura, Norihisa

    2015-01-01

    The purpose of this article was to provide an overview of the effects of the sleep education with self-help treatment for student, teacher, and local resident and sleep health promotion for mental and physical wellness for elderly with actual examples of public health from the community and schools. Sleep education with self-help treatment in schools revealed that delayed or irregular sleep/wake patterns were significantly improved. Also, it was effective for improving sleep-onset latency, sl...

  20. Sleep-dependent consolidation patterns reveal insights into episodic memory structure.

    Science.gov (United States)

    Oyanedel, Carlos N; Sawangjit, Anuck; Born, Jan; Inostroza, Marion

    2018-05-18

    Episodic memory formation is considered a genuinely hippocampal function. Its study in rodents has relied on two different task paradigms, i.e. the so called "what-where-when" (WW-When) task and "what-where-which" (WW-Which) task. The WW-When task aims to assess the memory for an episode as an event bound into its context defined by spatial and distinct temporal information, the WW-Which task lacks the temporal component and introduces, instead, an "occasion setter" marking the broader contextual configuration in which the event occurred. Whether both tasks measure episodic memory in an equivalent manner in terms of recollection has been controversially discussed. Here, we compared in two groups of rats the consolidating effects of sleep on episodic-like memory between both task paradigms. Sampling and test phases were separated by a 90-min morning retention interval which did or did not allow for spontaneous sleep. Results show that sleep is crucial for the consolidation of the memory on both tasks. However, consolidating effects of sleep were stronger for the WW-Which than WW-When task. Comparing performance during the post-sleep test phase revealed that WW-When memory only gradually emerged during the 3-min test period whereas WW-Which memory was readily expressed already from the first minute onward. Separate analysis of the temporal and spatial components of WW-When performance showed that the delayed episodic memory on this task originated from the temporal component which also did not emerge until the third minute of the test phase, whereas the spatial component already showed up in the first minute. In conclusion, sleep differentially affects consolidation on the two episodic-like memory tasks, with the delayed expression of WW-When memory after sleep resulting from preferential coverage of temporal aspects by this task. Copyright © 2018. Published by Elsevier Inc.

  1. Enhanced IMC based PID controller design for non-minimum phase (NMP) integrating processes with time delays.

    Science.gov (United States)

    Ghousiya Begum, K; Seshagiri Rao, A; Radhakrishnan, T K

    2017-05-01

    Internal model control (IMC) with optimal H 2 minimization framework is proposed in this paper for design of proportional-integral-derivative (PID) controllers. The controller design is addressed for integrating and double integrating time delay processes with right half plane (RHP) zeros. Blaschke product is used to derive the optimal controller. There is a single adjustable closed loop tuning parameter for controller design. Systematic guidelines are provided for selection of this tuning parameter based on maximum sensitivity. Simulation studies have been carried out on various integrating time delay processes to show the advantages of the proposed method. The proposed controller provides enhanced closed loop performances when compared to recently reported methods in the literature. Quantitative comparative analysis has been carried out using the performance indices, Integral Absolute Error (IAE) and Total Variation (TV). Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  2. Sleep and Premenstrual Syndrome

    Science.gov (United States)

    Jehan, Shazia; Auguste, Evan; Hussain, Mahjabeen; Pandi-Perumal, Seithikurippu R.; Brzezinski, Amon; Gupta, Ravi; Attarian, Hrayr; Jean-Louis, Giradin; McFarlane, Samy I.

    2016-01-01

    The etiology of premenstrual syndrome (PMS) is unknown; it may be due to the normal effect of hormones during the menstrual cycle as it occurs in the late luteal phase of the menstrual cycle.PMS affects women of childbearing age and remits with the onset of menstruation. The menstrual phase is known to influence stage 2 and REM sleep in women, irrespective of premenstrual dysphoric disorder (PMDD). Women with PMDD showed a decreased response to melatonin in their luteal phase as compared to the follicular phase of the menstrual cycle. However, melatonin duration or timing of offset in the morning has not been reported to correlate with the mood. Rather, improvement in mood-related symptoms of PMDD has been found to be influenced by sleep deprivation, be it sleep restrictions in early or late night. Sleep disturbance and decreased melatonin secretions due to hormonal fluctuations during the luteal phase of the menstrual cycle could explain the sleep complaints of PMDD. PMID:28239684

  3. Sub-nanometer distances and cluster shapes in dense hydrogen and in higher levels of hydrogen Rydberg matter by phase-delay spectroscopy

    International Nuclear Information System (INIS)

    Holmlid, Leif

    2011-01-01

    The inter-atomic distances in potassium clusters of Rydberg matter (RM) at excitation levels n B = 4–8 were recently measured by phase-delay spectroscopy (Holmlid, J Nanopart Res 12: 273, 2010). Excitation levels n B B = 1, 2, and 3 is found. Close-packing is the main structure both in planar and 3D clusters. Planar clusters are only observed for n B = 1 and 3, while 3D clusters are found in excitation levels n B = 1, 2 and 3. The cluster–cluster distance in stacks of planar clusters for n B = 2 and 3 is now observed for the first time.

  4. Circadian polymorphisms in night owls, in bipolars, and in non-24-hour sleep cycles.

    Science.gov (United States)

    Kripke, Daniel F; Klimecki, Walter T; Nievergelt, Caroline M; Rex, Katharine M; Murray, Sarah S; Shekhtman, Tatyana; Tranah, Gregory J; Loving, Richard T; Lee, Heon-Jeong; Rhee, Min Kyu; Shadan, Farhad F; Poceta, J Steven; Jamil, Shazia M; Kline, Lawrence E; Kelsoe, John R

    2014-10-01

    People called night owls habitually have late bedtimes and late times of arising, sometimes suffering a heritable circadian disturbance called delayed sleep phase syndrome (DSPS). Those with DSPS, those with more severe progressively-late non-24-hour sleep-wake cycles, and those with bipolar disorder may share genetic tendencies for slowed or delayed circadian cycles. We searched for polymorphisms associated with DSPS in a case-control study of DSPS research participants and a separate study of Sleep Center patients undergoing polysomnography. In 45 participants, we resequenced portions of 15 circadian genes to identify unknown polymorphisms that might be associated with DSPS, non-24-hour rhythms, or bipolar comorbidities. We then genotyped single nucleotide polymorphisms (SNPs) in both larger samples, using Illumina Golden Gate assays. Associations of SNPs with the DSPS phenotype and with the morningness-eveningness parametric phenotype were computed for both samples, then combined for meta-analyses. Delayed sleep and "eveningness" were inversely associated with loci in circadian genes NFIL3 (rs2482705) and RORC (rs3828057). A group of haplotypes overlapping BHLHE40 was associated with non-24-hour sleep-wake cycles, and less robustly, with delayed sleep and bipolar disorder (e.g., rs34883305, rs34870629, rs74439275, and rs3750275 were associated with n=37, p=4.58E-09, Bonferroni p=2.95E-06). Bright light and melatonin can palliate circadian disorders, and genetics may clarify the underlying circadian photoperiodic mechanisms. After further replication and identification of the causal polymorphisms, these findings may point to future treatments for DSPS, non-24-hour rhythms, and possibly bipolar disorder or depression.

  5. Pulsing blue light through closed eyelids: effects on acute melatonin suppression and phase shifting of dim light melatonin onset.

    Science.gov (United States)

    Figueiro, Mariana G; Plitnick, Barbara; Rea, Mark S

    2014-01-01

    Circadian rhythm disturbances parallel the increased prevalence of sleep disorders in older adults. Light therapies that specifically target regulation of the circadian system in principle could be used to treat sleep disorders in this population. Current recommendations for light treatment require the patients to sit in front of a bright light box for at least 1 hour daily, perhaps limiting their willingness to comply. Light applied through closed eyelids during sleep might not only be efficacious for changing circadian phase but also lead to better compliance because patients would receive light treatment while sleeping. Reported here are the results of two studies investigating the impact of a train of 480 nm (blue) light pulses presented to the retina through closed eyelids on melatonin suppression (laboratory study) and on delaying circadian phase (field study). Both studies employed a sleep mask that provided narrowband blue light pulses of 2-second duration every 30 seconds from arrays of light-emitting diodes. The results of the laboratory study demonstrated that the blue light pulses significantly suppressed melatonin by an amount similar to that previously shown in the same protocol at half the frequency (ie, one 2-second pulse every minute for 1 hour). The results of the field study demonstrated that blue light pulses given early in the sleep episode significantly delayed circadian phase in older adults; these results are the first to demonstrate the efficacy and practicality of light treatment by a sleep mask aimed at adjusting circadian phase in a home setting.

  6. Healthy Sleep Habits

    Science.gov (United States)

    ... Sleep Apnea Testing CPAP Healthy Sleep Habits Healthy Sleep Habits Your behaviors during the day, and especially ... team at an AASM accredited sleep center . Quick Sleep Tips Follow these tips to establish healthy sleep ...

  7. Obstructive Sleep Apnea

    Medline Plus

    Full Text Available ... find out more. Obstructive Sleep Apnea (OSA) Obstructive Sleep Apnea (OSA) Obstructive sleep apnea (OSA) is a ... find out more. Obstructive Sleep Apnea (OSA) Obstructive Sleep Apnea (OSA) Obstructive sleep apnea (OSA) is a ...

  8. Obstructive Sleep Apnea

    Science.gov (United States)

    ... find out more. Obstructive Sleep Apnea (OSA) Obstructive Sleep Apnea (OSA) Obstructive sleep apnea (OSA) is a ... find out more. Obstructive Sleep Apnea (OSA) Obstructive Sleep Apnea (OSA) Obstructive sleep apnea (OSA) is a ...

  9. Small-Signal Modeling, Stability Analysis and Design Optimization of Single-Phase Delay-Based PLLs

    DEFF Research Database (Denmark)

    Golestan, Saeed; Guerrero, Josep M.; Vidal, Ana

    2016-01-01

    Generally speaking, designing single-phase phaselocked loops (PLLs) is more complicated than three-phase ones, as their implementation often involves the generation of a fictitious orthogonal signal for the frame transformation. In recent years, many approaches to generate the orthogonal signal...... these issues and explore new methods to enhance their performance. The stability analysis, control design guidelines and performance comparison with the state-of-the-art PLLs are presented as well....

  10. Sleep Apnea

    Science.gov (United States)

    Sleep apnea is a common disorder that causes your breathing to stop or get very shallow. Breathing ... an hour. The most common type is obstructive sleep apnea. It causes your airway to collapse or ...

  11. Efficacy, Safety, and Dose of Pafuramidine, a New Oral Drug for Treatment of First Stage Sleeping Sickness, in a Phase 2a Clinical Study and Phase 2b Randomized Clinical Studies.

    Directory of Open Access Journals (Sweden)

    Christian Burri

    2016-02-01

    Full Text Available Sleeping sickness (human African trypanosomiasis [HAT] is caused by protozoan parasites and characterized by a chronic progressive course, which may last up to several years before death. We conducted two Phase 2 studies to determine the efficacy and safety of oral pafuramidine in African patients with first stage HAT.The Phase 2a study was an open-label, non-controlled, proof-of-concept study where 32 patients were treated with 100 mg of pafuramidine orally twice a day (BID for 5 days at two trypanosomiasis reference centers (Angola and the Democratic Republic of the Congo [DRC] between August 2001 and November 2004. The Phase 2b study compared pafuramidine in 41 patients versus standard pentamidine therapy in 40 patients. The Phase 2b study was open-label, parallel-group, controlled, randomized, and conducted at two sites in the DRC between April 2003 and February 2007. The Phase 2b study was then amended to add an open-label sequence (Phase 2b-2, where 30 patients received pafuramidine for 10 days. The primary efficacy endpoint was parasitologic cure at 24 hours (Phase 2a or 3 months (Phase 2b after treatment completion. The primary safety outcome was the rate of occurrence of World Health Organization Toxicity Scale Grade 3 or higher adverse events. All subjects provided written informed consent.Pafuramidine for the treatment of first stage HAT was comparable in efficacy to pentamidine after 10 days of dosing. The cure rates 3 months post-treatment were 79% in the 5-day pafuramidine, 100% in the 7-day pentamidine, and 93% in the 10-day pafuramidine groups. In Phase 2b, the percentage of patients with at least 1 treatment-emergent adverse event was notably higher after pentamidine treatment (93% than pafuramidine treatment for 5 days (25% and 10 days (57%. These results support continuation of the development program for pafuramidine into Phase 3.

  12. Efficacy, Safety, and Dose of Pafuramidine, a New Oral Drug for Treatment of First Stage Sleeping Sickness, in a Phase 2a Clinical Study and Phase 2b Randomized Clinical Studies.

    Science.gov (United States)

    Burri, Christian; Yeramian, Patrick D; Allen, James L; Merolle, Ada; Serge, Kazadi Kyanza; Mpanya, Alain; Lutumba, Pascal; Mesu, Victor Kande Betu Ku; Bilenge, Constantin Miaka Mia; Lubaki, Jean-Pierre Fina; Mpoto, Alfred Mpoo; Thompson, Mark; Munungu, Blaise Fungula; Manuel, Francisco; Josenando, Théophilo; Bernhard, Sonja C; Olson, Carol A; Blum, Johannes; Tidwell, Richard R; Pohlig, Gabriele

    2016-02-01

    Sleeping sickness (human African trypanosomiasis [HAT]) is caused by protozoan parasites and characterized by a chronic progressive course, which may last up to several years before death. We conducted two Phase 2 studies to determine the efficacy and safety of oral pafuramidine in African patients with first stage HAT. The Phase 2a study was an open-label, non-controlled, proof-of-concept study where 32 patients were treated with 100 mg of pafuramidine orally twice a day (BID) for 5 days at two trypanosomiasis reference centers (Angola and the Democratic Republic of the Congo [DRC]) between August 2001 and November 2004. The Phase 2b study compared pafuramidine in 41 patients versus standard pentamidine therapy in 40 patients. The Phase 2b study was open-label, parallel-group, controlled, randomized, and conducted at two sites in the DRC between April 2003 and February 2007. The Phase 2b study was then amended to add an open-label sequence (Phase 2b-2), where 30 patients received pafuramidine for 10 days. The primary efficacy endpoint was parasitologic cure at 24 hours (Phase 2a) or 3 months (Phase 2b) after treatment completion. The primary safety outcome was the rate of occurrence of World Health Organization Toxicity Scale Grade 3 or higher adverse events. All subjects provided written informed consent. Pafuramidine for the treatment of first stage HAT was comparable in efficacy to pentamidine after 10 days of dosing. The cure rates 3 months post-treatment were 79% in the 5-day pafuramidine, 100% in the 7-day pentamidine, and 93% in the 10-day pafuramidine groups. In Phase 2b, the percentage of patients with at least 1 treatment-emergent adverse event was notably higher after pentamidine treatment (93%) than pafuramidine treatment for 5 days (25%) and 10 days (57%). These results support continuation of the development program for pafuramidine into Phase 3.

  13. Multi-detector row CT of the kidney: Optimizing scan delays for bolus tracking techniques of arterial, corticomedullary, and nephrographic phases

    Energy Technology Data Exchange (ETDEWEB)

    Goshima, Satoshi [Department of Radiology, Gifu University School of Medicine, 1-1 Yanagido, Gifu 501-1193 (Japan); Kanematsu, Masayuki [Department of Radiology, Gifu University School of Medicine, 1-1 Yanagido, Gifu 501-1193 (Japan); Department of Radiology Services, Gifu University School of Medicine, 1-1 Yanagido, Gifu 501-1193 (Japan); Nishibori, Hironori; Kondo, Hiroshi; Tsuge, Yusuke [Department of Radiology, Gifu University School of Medicine, 1-1 Yanagido, Gifu 501-1193 (Japan); Yokoyama, Ryujiro; Miyoshi, Toshiharu [Department of Radiology Services, Gifu University School of Medicine, 1-1 Yanagido, Gifu 501-1193 (Japan); Onozuka, Minoru [Department of Physiology and Neuroscience, Kanagawa Dental College, Yokosuka, Kanagawa (Japan); Shiratori, Yoshimune [Department of Medical Informatics, Gifu University School of Medicine, Gifu (Japan); Moriyama, Noriyuki [Department of Diagnostic Radiology, National Cancer Center Hospital, Tsukiji, Chuo-Ku, Tokyo (Japan); Bae, Kyongtae T. [Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO (United States)

    2007-09-15

    Purpose: To determine optimal scan delays for renal arterial-, corticomedullary-, and nephrographic-phase imaging with multi-detector row computed tomography (MDCT) of the kidney using a bolus-tracking technique. Methods and materials: One hundred and twenty-eight patients underwent three-phase CT scan of the kidney with eight-row MDCT after receiving 2 mL/kg of 300 mg I/mL contrast medium at 4 mL/s. Patients were prospectively randomized into three groups with different scan delays for the three scan phases (arterial, corticomedullary, and nephrographic) after bolus-tracking triggered at 50 HU of aortic contrast enhancement: group 1 (5, 20, 45 s); group 2 (10, 25, 50 s); and group 3 (15, 30, 55 s). Mean CT values (HU) of the abdominal aorta, renal artery, renal vein, renal cortex, and renal medulla were measured; increases in CT values pre- to post-contrast were assessed as contrast enhancement. Renal artery-to-vein and renal cortex-to-medulla contrast differences were also assessed. Qualitative analysis was also performed. Results: Mean renal artery enhancement was 240-288 HU at 5-15 s after the trigger and peaked at 10 s (P < .001). Mean renal cortical enhancement was 195-217 HU at 10-30 s and peaked at 25 s (P < .01). Contrast enhancement in the renal medulla increased gradually and reached mean 145 HU at 55 s. Cortex-to-medulla contrast difference was high (110-140 HU) at 5-30 s and decreased below 30 HU at 45 s after the trigger. Renal artery-to-vein contrast difference was high (121-125 HU) at 5-10 s. Qualitative results correlated well with quantitative results. Conclusion: For the injection protocol used in this study, optimal scan delays after the bolus-tracking trigger were 5-10 s for renal arterial, 15-25 s for corticomedullary, and 50-55 s for nephrographic phases.

  14. The Timing of the Circadian Clock and Sleep Differ between Napping and Non-Napping Toddlers.

    Science.gov (United States)

    Akacem, Lameese D; Simpkin, Charles T; Carskadon, Mary A; Wright, Kenneth P; Jenni, Oskar G; Achermann, Peter; LeBourgeois, Monique K

    2015-01-01

    The timing of the internal circadian clock shows large inter-individual variability across the lifespan. Although the sleep-wakefulness pattern of most toddlers includes an afternoon nap, the association between napping and circadian phase in early childhood remains unexplored. This study examined differences in circadian phase and sleep between napping and non-napping toddlers. Data were collected on 20 toddlers (34.2±2.0 months; 12 females; 15 nappers). Children followed their habitual napping and non-napping sleep schedules (monitored with actigraphy) for 5 days before an in-home salivary dim light melatonin onset (DLMO) assessment. On average, napping children fell asleep during their nap opportunities on 3.6±1.2 of the 5 days before the DLMO assessment. For these napping children, melatonin onset time was 38 min later (p = 0.044; d = 0.93), actigraphically-estimated bedtime was 43 min later (p = 0.014; d = 1.24), sleep onset time was 59 min later (p = 0.006; d = 1.46), and sleep onset latency was 16 min longer (p = 0.030; d = 1.03) than those not napping. Midsleep and wake time did not differ by napping status. No difference was observed in the bedtime, sleep onset, or midsleep phase relationships with DLMO; however, the wake time phase difference was 47 min smaller for napping toddlers (p = 0.029; d = 1.23). On average, nappers had 69 min shorter nighttime sleep durations (p = 0.006; d = 1.47) and spent 49 min less time in bed (p = 0.019; d = 1.16) than non-nappers. Number of days napping was correlated with melatonin onset time (r = 0.49; p = 0.014). Our findings indicate that napping influences individual variability in melatonin onset time in early childhood. The delayed bedtimes of napping toddlers likely permits light exposure later in the evening, thereby delaying the timing of the clock and sleep. Whether the early developmental trajectory of circadian phase involves an advance associated with the decline in napping is a question necessitating

  15. The Timing of the Circadian Clock and Sleep Differ between Napping and Non-Napping Toddlers.

    Directory of Open Access Journals (Sweden)

    Lameese D Akacem

    Full Text Available The timing of the internal circadian clock shows large inter-individual variability across the lifespan. Although the sleep-wakefulness pattern of most toddlers includes an afternoon nap, the association between napping and circadian phase in early childhood remains unexplored. This study examined differences in circadian phase and sleep between napping and non-napping toddlers. Data were collected on 20 toddlers (34.2±2.0 months; 12 females; 15 nappers. Children followed their habitual napping and non-napping sleep schedules (monitored with actigraphy for 5 days before an in-home salivary dim light melatonin onset (DLMO assessment. On average, napping children fell asleep during their nap opportunities on 3.6±1.2 of the 5 days before the DLMO assessment. For these napping children, melatonin onset time was 38 min later (p = 0.044; d = 0.93, actigraphically-estimated bedtime was 43 min later (p = 0.014; d = 1.24, sleep onset time was 59 min later (p = 0.006; d = 1.46, and sleep onset latency was 16 min longer (p = 0.030; d = 1.03 than those not napping. Midsleep and wake time did not differ by napping status. No difference was observed in the bedtime, sleep onset, or midsleep phase relationships with DLMO; however, the wake time phase difference was 47 min smaller for napping toddlers (p = 0.029; d = 1.23. On average, nappers had 69 min shorter nighttime sleep durations (p = 0.006; d = 1.47 and spent 49 min less time in bed (p = 0.019; d = 1.16 than non-nappers. Number of days napping was correlated with melatonin onset time (r = 0.49; p = 0.014. Our findings indicate that napping influences individual variability in melatonin onset time in early childhood. The delayed bedtimes of napping toddlers likely permits light exposure later in the evening, thereby delaying the timing of the clock and sleep. Whether the early developmental trajectory of circadian phase involves an advance associated with the decline in napping is a question

  16. Baird-Pattinson Aetiological Classification and Phases of Delay Contributing to Stillbirths in a Nigerian Tertiary Hospital

    Directory of Open Access Journals (Sweden)

    Jacob Olumuyiwa Awoleke

    2016-01-01

    Full Text Available Purpose. This study aims to identify triggers of stillbirth in the study setting and to make suggestions to reduce the prevalence. Method. A three-year retrospective case-control study of stillbirths at Ekiti State University Teaching Hospital. Results. The stillbirth rate was 33 per 1000 births. Based on Baird-Pattinson classification of the primary obstetric causes of stillbirth, adverse intrapartum events, hypertensive diseases, and unexplained intrapartum fetal deaths were topmost causes of stillbirths. In comparison with the controls, other identified predictors of SB were grand multiparity (p=0.016, delays in seeking medical care and/or in receiving treatment (p=0.001, wrong initial diagnosis (p=0.001, inadequate intrapartum monitoring (p=0.001, and inappropriate clinical management (p=0.001. Conclusion. Stillbirth rate remains high in our setting. Elimination of obstacles to accessing care, effective management of hypertensive disorders in pregnancy, updated health facilities, improved dedication to duty, and retraining of health workers will reduce the prevalence.

  17. Description of a Sleep-Restriction Program to Reduce Bedtime Disturbances and Night Waking

    Science.gov (United States)

    Durand, V. Mark; Christodulu, Kristin V.

    2004-01-01

    The authors describe a behavioral intervention designed to reduce sleep problems without increasing disruption at bedtime or throughout the evening. Sleep restriction was used to reduce the bedtime and nighttime sleep problems of two children, a 4-year-old girl with autism and a 4-year-old girl with developmental delay. Sleep restriction involved…

  18. Voluntary Sleep Loss in Rats

    Science.gov (United States)

    Oonk, Marcella; Krueger, James M.; Davis, Christopher J.

    2016-01-01

    Study Objectives: Animal sleep deprivation (SDEP), in contrast to human SDEP, is involuntary and involves repeated exposure to aversive stimuli including the inability of the animal to control the waking stimulus. Therefore, we explored intracranial self-stimulation (ICSS), an operant behavior, as a method for voluntary SDEP in rodents. Methods: Male Sprague-Dawley rats were implanted with electroencephalography/electromyography (EEG/EMG) recording electrodes and a unilateral bipolar electrode into the lateral hypothalamus. Rats were allowed to self-stimulate, or underwent gentle handling-induced SDEP (GH-SDEP), during the first 6 h of the light phase, after which they were allowed to sleep. Other rats performed the 6 h ICSS and 1 w later were subjected to 6 h of noncontingent stimulation (NCS). During NCS the individual stimulation patterns recorded during ICSS were replayed. Results: After GH-SDEP, ICSS, or NCS, time in nonrapid eye movement (NREM) sleep and rapid eye movement (REM) sleep increased. Further, in the 24 h after SDEP, rats recovered all of the REM sleep lost during SDEP, but only 75% to 80% of the NREM sleep lost, regardless of the SDEP method. The magnitude of EEG slow wave responses occurring during NREM sleep also increased after SDEP treatments. However, NREM sleep EEG slow wave activity (SWA) responses were attenuated following ICSS, compared to GH-SDEP and NCS. Conclusions: We conclude that ICSS and NCS can be used to sleep deprive rats. Changes in rebound NREM sleep EEG SWA occurring after ICSS, NCS, and GH-SDEP suggest that nonspecific effects of the SDEP procedure differentially affect recovery sleep phenotypes. Citation: Oonk M, Krueger JM, Davis CJ. Voluntary sleep loss in rats. SLEEP 2016;39(7):1467–1479. PMID:27166236

  19. Clinical validity of delayed recall tests as a gateway biomarker for Alzheimer's disease in the context of a structured 5-phase development framework.

    Science.gov (United States)

    Cerami, Chiara; Dubois, Bruno; Boccardi, Marina; Monsch, Andreas U; Demonet, Jean Francois; Cappa, Stefano F

    2017-04-01

    Although Alzheimer's disease criteria promote the use of biomarkers, their maturity in clinical routine still needs to be assessed. In the light of the oncology framework, we conducted a literature review on measures used to assess delayed recall impairment due to medial temporal lobe dysfunction (i.e., free and cued word list recall tests). Ample evidence is available for phases 1 (rationale for use), 2 (discriminative ability), and 3 (early detection ability) for many of the tests in routine use. Evidence about phase 4 (performance in real world) and phase 5 (quantify impact and costs) is yet to come. Administration procedures have been standardized and cutoff scores are well validated in large Alzheimer's disease and mild cognitive impaired series. Some aspects (e.g., different task formats), however, hamper the comparability of results among different populations and the reproducibility between laboratories. No definite guideline for their use can thus be proposed at the moment. Accordingly, the maturity of such markers is not yet sufficient and requires future investigation to promote the proper use of memory measures in clinical settings. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Multi-Gbit/s optical phase chaos communications using a time-delayed optoelectronic oscillator with a three-wave interferometer nonlinearity

    Science.gov (United States)

    Oden, Jérémy; Lavrov, Roman; Chembo, Yanne K.; Larger, Laurent

    2017-11-01

    We propose a chaos communication scheme based on a chaotic optical phase carrier generated with an optoelectronic oscillator with nonlinear time-delay feedback. The system includes a dedicated non-local nonlinearity, which is a customized three-wave imbalanced interferometer. This particular feature increases the complexity of the chaotic waveform and thus the security of the transmitted information, as these interferometers are characterized by four independent parameters which are part of the secret key for the chaos encryption scheme. We first analyze the route to chaos in the system, and evidence a sequence of period doubling bifurcations from the steady-state to fully developed chaos. Then, in the chaotic regime, we study the synchronization between the emitter and the receiver, and achieve chaotic carrier cancellation with a signal-to-noise ratio up to 20 dB. We finally demonstrate error-free chaos communications at a data rate of 3 Gbit/s.

  1. Multi-Gbit/s optical phase chaos communications using a time-delayed optoelectronic oscillator with a three-wave interferometer nonlinearity.

    Science.gov (United States)

    Oden, Jérémy; Lavrov, Roman; Chembo, Yanne K; Larger, Laurent

    2017-11-01

    We propose a chaos communication scheme based on a chaotic optical phase carrier generated with an optoelectronic oscillator with nonlinear time-delay feedback. The system includes a dedicated non-local nonlinearity, which is a customized three-wave imbalanced interferometer. This particular feature increases the complexity of the chaotic waveform and thus the security of the transmitted information, as these interferometers are characterized by four independent parameters which are part of the secret key for the chaos encryption scheme. We first analyze the route to chaos in the system, and evidence a sequence of period doubling bifurcations from the steady-state to fully developed chaos. Then, in the chaotic regime, we study the synchronization between the emitter and the receiver, and achieve chaotic carrier cancellation with a signal-to-noise ratio up to 20 dB. We finally demonstrate error-free chaos communications at a data rate of 3 Gbit/s.

  2. Phase time delay and Hartman effect in a one-dimensional photonic crystal with four-level atomic defect layer

    Science.gov (United States)

    Jamil, Rabia; Ali, Abu Bakar; Abbas, Muqaddar; Badshah, Fazal; Qamar, Sajid

    2017-08-01

    The Hartman effect is revisited using a Gaussian beam incident on a one-dimensional photonic crystal (1DPC) having a defect layer doped with four-level atoms. It is considered that each atom of the defect layer interacts with three driving fields, whereas a Gaussian beam of width w is used as a probe light to study Hartman effect. The atom-field interaction inside the defect layer exhibits electromagnetically induced transparency (EIT). The 1DPC acts as positive index material (PIM) and negative index material (NIM) corresponding to the normal and anomalous dispersion of the defect layer, respectively, via control of the phase associated with the driving fields and probe detuning. The positive and negative Hartman effects are noticed for PIM and NIM, respectively, via control of the relative phase corresponding to the driving fields and probe detuning. The advantage of using four-level EIT system is that a much smaller absorption of the transmitted beam occurs as compared to three-level EIT system corresponding to the anomalous dispersion, leading to negative Hartman effect.

  3. Depression and poor sleep

    DEFF Research Database (Denmark)

    Sánchez, Connie; Brennum, Lise T; Stórustovu, Signe í

    2007-01-01

    The effects of five antidepressants (escitalopram, paroxetine, duloxetine, venlafaxine, and reboxetine) on the sleep architecture were investigated in freely moving rats in the light phase of a 12:12 h light:dark cycle following a single i.p. dose of antidepressant. Overall, paroxetine and escita...

  4. Sleep in thyrotoxicosis

    Directory of Open Access Journals (Sweden)

    G R Sridhar

    2011-01-01

    Full Text Available Objective: Pattern of sleep in hyperthyroid state / thyrotoxicosis has not been systematically studied. It is being characterized as poor without further elaboration. We analyzed the pattern of sleep in a large sample of individuals with thyrotoxicosis who came to our endocrine center in southern India. Materials and Methods: We identified individuals with the diagnosis of ′thyrotoxicosis′ from our electronic medical record database, and evaluated clinical parameters and pattern of their sleep: difficulty in falling asleep (DFA, difficulty in maintaining sleep (DMS, excess daytime sleepiness. In the first phase, univariate analysis with logistic regression was performed. Multivariate logistic regression was performed in the next phase on variables with a P-value < 0.1: these were considered as potential categories/ variables. Results: In model response variable with DFA, multivariate logistic regression predicted that subjects with abnormal appetite (more 1.7 or less 2.2, change in bowel motion (loose 1.5 or constipation 2.8, in mood (easy loss of temper 3.4, change of voice -- hoarse 7.4 or moderately hoarse 3.1, tended to have higher chances of difficulty in falling asleep (DFA. Patients with tremor (yes = 5.4 had greater likelihood of difficulty in maintaining sleep (DMS. Conclusions: Individuals with hyperthyroidism/thyrotoxicosis principally had difficulty in falling asleep DFA, which was related to hyperkinetic features.

  5. Impact of Sleep Telemedicine Protocol in Management of Sleep Apnea: A 5-Year VA Experience.

    Science.gov (United States)

    Baig, Mirza M; Antonescu-Turcu, Andrea; Ratarasarn, Kavita

    2016-05-01

    There is growing evidence that demonstrates an important role for telemedicine technologies in enhancing healthcare delivery. A comprehensive sleep telemedicine protocol was implemented at the Veterans Administration Medical Center (VAMC), Milwaukee, WI, in 2008 in an effort to improve access to sleep specialty care. The telemedicine protocol relied heavily on sleep specialist interventions based on chart review (electronic consult [e-consult]). This was done in response to long wait time for sleep clinic visits as well as delayed sleep study appointments. Since 2008 all consults are screened by sleep service to determine the next step in intervention. Based on chart review, the following steps are undertaken: (1) eligibility for portable versus in-lab sleep study is determined, and a sleep study order is placed accordingly, (2) positive airway pressure (PAP) therapy is prescribed for confirmed sleep apnea, and (3) need for in-person evaluation in the sleep clinic is determined, and the visit is scheduled. This study summarizes the 5-year trend in various aspects of access to sleep care after implementation of sleep telemedicine protocol at the Milwaukee VAMC. This is a retrospective system efficiency study. The electronic medical record was interrogated 5 years after starting the sleep telemedicine protocol to study annual trends in the following outcomes: (1) interval between sleep consult and prescription of PAP equipment, (2) total sleep consults, and (3) sleep clinic wait time. Two part-time sleep physicians provided sleep-related care at the Milwaukee VAMC between 2008 and 2012. During this period, the interval between sleep consult and PAP prescription decreased from ≥60 days to ≤7 days. This occurred in spite of an increase in total sleep consults and sleep studies. There was also a significant increase in data downloads, indicating overall improved follow-up. There was no change in clinic wait time of ≥60 days. Implementation of a sleep telemedicine

  6. Sleep disorders - overview

    Science.gov (United States)

    Insomnia; Narcolepsy; Hypersomina; Daytime sleepiness; Sleep rhythm; Sleep disruptive behaviors; Jet lag ... excessive daytime sleepiness) Problems sticking to a regular sleep schedule (sleep rhythm problem) Unusual behaviors during sleep ( ...

  7. Central sleep apnea

    Science.gov (United States)

    Sleep apnea - central; Obesity - central sleep apnea; Cheyne-Stokes - central sleep apnea; Heart failure - central sleep apnea ... Central sleep apnea results when the brain temporarily stops sending signals to the muscles that control breathing. The condition ...

  8. Sleep Apnea (For Parents)

    Science.gov (United States)

    ... Safe Videos for Educators Search English Español Obstructive Sleep Apnea KidsHealth / For Parents / Obstructive Sleep Apnea What's ... How Is Sleep Apnea Treated? Print What Is Sleep Apnea? Brief pauses in breathing during sleep are ...

  9. Delayed fission

    Energy Technology Data Exchange (ETDEWEB)

    Hatsukawa, Yuichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-07-01

    Delayed fission is a nuclear decay process that couples {beta} decay and fission. In the delayed fission process, a parent nucleus undergoes {beta} decay and thereby populates excited states in the daughter. If these states are of energies comparable to or greater than the fission barrier of the daughter, then fission may compete with other decay modes of the excited states in the daughter. In this paper, mechanism and some experiments of the delayed fission will be discussed. (author)

  10. The anticipation and outcome phases of reward and loss processing: A neuroimaging meta-analysis of the monetary incentive delay task.

    Science.gov (United States)

    Oldham, Stuart; Murawski, Carsten; Fornito, Alex; Youssef, George; Yücel, Murat; Lorenzetti, Valentina

    2018-04-25

    The processing of rewards and losses are crucial to everyday functioning. Considerable interest has been attached to investigating the anticipation and outcome phases of reward and loss processing, but results to date have been inconsistent. It is unclear if anticipation and outcome of a reward or loss recruit similar or distinct brain regions. In particular, while the striatum has widely been found to be active when anticipating a reward, whether it activates in response to the anticipation of losses as well remains ambiguous. Furthermore, concerning the orbitofrontal/ventromedial prefrontal regions, activation is often observed during reward receipt. However, it is unclear if this area is active during reward anticipation as well. We ran an Activation Likelihood Estimation meta-analysis of 50 fMRI studies, which used the Monetary Incentive Delay Task (MIDT), to identify which brain regions are implicated in the anticipation of rewards, anticipation of losses, and the receipt of reward. Anticipating rewards and losses recruits overlapping areas including the striatum, insula, amygdala and thalamus, suggesting that a generalised neural system initiates motivational processes independent of valence. The orbitofrontal/ventromedial prefrontal regions were recruited only during the reward outcome, likely representing the value of the reward received. Our findings help to clarify the neural substrates of the different phases of reward and loss processing, and advance neurobiological models of these processes. © 2018 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

  11. Formation and suppression of acoustic memories during human sleep.

    Science.gov (United States)

    Andrillon, Thomas; Pressnitzer, Daniel; Léger, Damien; Kouider, Sid

    2017-08-08

    Sleep and memory are deeply related, but the nature of the neuroplastic processes induced by sleep remains unclear. Here, we report that memory traces can be both formed or suppressed during sleep, depending on sleep phase. We played samples of acoustic noise to sleeping human listeners. Repeated exposure to a novel noise during Rapid Eye Movements (REM) or light non-REM (NREM) sleep leads to improvements in behavioral performance upon awakening. Strikingly, the same exposure during deep NREM sleep leads to impaired performance upon awakening. Electroencephalographic markers of learning extracted during sleep confirm a dissociation between sleep facilitating memory formation (light NREM and REM sleep) and sleep suppressing learning (deep NREM sleep). We can trace these neural changes back to transient sleep events, such as spindles for memory facilitation and slow waves for suppression. Thus, highly selective memory processes are active during human sleep, with intertwined episodes of facilitative and suppressive plasticity.Though memory and sleep are related, it is still unclear whether new memories can be formed during sleep. Here, authors show that people could learn new sounds during REM or light non-REM sleep, but that learning was suppressed when sounds were played during deep NREM sleep.

  12. Sleep and Women’s Health

    Directory of Open Access Journals (Sweden)

    Sara Nowakowski

    2013-06-01

    Full Text Available Sex differences in sleep begin at a very early age and women report poorer sleep quality and have higher risk for insomnia than do men. Sleep may be affected by variation in reproductive hormones, stress, depression, aging, life/role transitions, and other factors. The menstrual cycle is associated with changes in circadian rhythms and sleep architecture. Menstruating women (even without significant menstrual-related complaints often report poorer sleep quality and greater sleep disturbance during the premenstrual week compared to other times of her menstrual cycle. In addition to these sleep disturbances, women with severe premenstrual syndrome often report more disturbing dreams, sleepiness, fatigue, decreased alertness and concentration during the premenstrual phase. Sleep disturbances are also commonly reported during pregnancy and increase in frequency and duration as the pregnancy progresses. The precipitous decline in hormones and unpredictable sleep patterns of the newborn contribute to and/or exacerbate poor sleep and daytime sleepiness during the early postpartum period. Insomnia is also among the most common health complaints that are reported by perimenopausal women. Women are particularly vulnerable to developing insomnia disorder during these times of reproductive hormonal change. In this review, we present a discussion on the most relevant and recent publications on sleep across the woman’s lifespan, including changes in sleep related to menstruation, pregnancy, postpartum, and the menopausal transition. Treatment for sleep disturbances and insomnia disorder and special considerations for treating women will also be discussed.

  13. PPARα is a potential therapeutic target of drugs to treat circadian rhythm sleep disorders

    International Nuclear Information System (INIS)

    Shirai, Hidenori; Oishi, Katsutaka; Kudo, Takashi; Shibata, Shigenobu; Ishida, Norio

    2007-01-01

    Recent progress at the molecular level has revealed that nuclear receptors play an important role in the generation of mammalian circadian rhythms. To examine whether peroxisome proliferator-activated receptor alpha (PPARα) is involved in the regulation of circadian behavioral rhythms in mammals, we evaluated the locomotor activity of mice administered with the hypolipidemic PPARα ligand, bezafibrate. Circadian locomotor activity was phase-advanced about 3 h in mice given bezafibrate under light-dark (LD) conditions. Transfer from LD to constant darkness did not change the onset of activity in these mice, suggesting that bezafibrate advanced the phase of the endogenous clock. Surprisingly, bezafibrate also advanced the phase in mice with lesions of the suprachiasmatic nucleus (SCN; the central clock in mammals). The circadian expression of clock genes such as period2, BMAL1, and Rev-erbα was also phase-advanced in various tissues (cortex, liver, and fat) without affecting the SCN. Bezafibrate also phase-advanced the activity phase that is delayed in model mice with delayed sleep phase syndrome (DSPS) due to a Clock gene mutation. Our results indicated that PPARα is involved in circadian clock control independently of the SCN and that PPARα could be a potent target of drugs to treat circadian rhythm sleep disorders including DSPS

  14. [Sleep paroxysmal events in children in video/polysomnography].

    Science.gov (United States)

    Zajac, Anna; Skowronek-Bała, Barbara; Wesołowska, Ewa; Kaciński, Marek

    2010-01-01

    It is estimated that about 25% of children have sleep disorders, from short problems with falling asleep to severe including primary sleep disorders. Majority of these problems are transitory and self-limiting and usually are not recognized by first care physicians and need education. Analysis of sleep structure at the developmental age and of sleep disorders associated with different sleep phases on the basis of video/polysomnography results. Literature review and illustration of fundamental problems associated with sleep physiology and pathology, with special attention to paroxysmal disorders. Additionally 4 cases from our own experience were presented with neurophysiological and clinical aspects. Discussion on REM and NREM sleep, its phases and alternating share according to child's age was conducted. Sleep disorders were in accordance with their international classification. Parasomnias, occupying most of the space, were divided in two groups: primary and secondary. Among primary parasomnias disorders associated with falling asleep (sleep myoclonus, hypnagogic hallucinations, sleep paralysis, rhythmic movement disorder, restless legs syndrome) are important. Another disorders are parasomians associated with light NREM sleep (bruxism, periodic limb movement disorder) and with deeper NREM sleep (confusional arousals, somnabulism, night terrors), with REM sleep (nightmares, REM sleep behavior disorder) and associated with NREM and REM sleep (catathrenia, sleep enuresis, sleep talking). Obstructive sleep apnea syndrome and epileptic seizures occurring during sleep also play an important role. Frontal lobe epilepsy and Panayiotopoulos syndrome should be considered in the first place in such cases. Our 4 cases document these diagnostic difficulties, requiring video/polysomnography examination 2 of them illustrate frontal lobe epilepsy and single ones myoclonic epilepsy graphy in children is a difficult technique and requires special device, local and trained

  15. Preoperative Short-Course Concurrent Chemoradiation Therapy Followed by Delayed Surgery for Locally Advanced Rectal Cancer: A Phase 2 Multicenter Study (KROG 10-01)

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    Yeo, Seung-Gu [Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Goyang (Korea, Republic of); Department of Radiation Oncology, Soonchunhyang University College of Medicine, Cheonan (Korea, Republic of); Oh, Jae Hwan [Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Goyang (Korea, Republic of); Kim, Dae Yong, E-mail: radiopiakim@hanmail.net [Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Goyang (Korea, Republic of); Baek, Ji Yeon; Kim, Sun Young; Park, Ji Won; Kim, Min Ju; Chang, Hee Jin; Kim, Tae Hyun [Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Goyang (Korea, Republic of); Lee, Jong Hoon; Jang, Hong Seok [Department of Radiation Oncology, Seoul St. Mary' s Hospital, College of Medicine, The Catholic University of Korea, Seoul (Korea, Republic of); Kim, Jun-Gi [Department of Surgery, Seoul St. Mary' s Hospital, College of Medicine, The Catholic University of Korea, Seoul (Korea, Republic of); Lee, Myung Ah [Department of Internal Medicine, Seoul St. Mary' s Hospital, College of Medicine, The Catholic University of Korea, Seoul (Korea, Republic of); Nam, Taek-Keun [Department of Radiation Oncology, Chonnam National University Hospital, Gwang-Ju (Korea, Republic of)

    2013-05-01

    Purpose: A prospective phase 2 multicenter trial was performed to investigate the efficacy and safety of preoperative short-course concurrent chemoradiation therapy (CRT) followed by delayed surgery for patients with locally advanced rectal cancer. Methods and Materials: Seventy-three patients with cT3-4 rectal cancer were enrolled. Radiation therapy of 25 Gy in 5 fractions was delivered over 5 consecutive days using helical tomotherapy. Concurrent chemotherapy was administered on the same 5 days with intravenous bolus injection of 5-fluorouracil (400 mg/m{sup 2}/day) and leucovorin (20 mg/m{sup 2}/day). After 4 to 8 weeks, total mesorectal excision was performed. The primary endpoint was the pathologic downstaging (ypStage 0-I) rate, and secondary endpoints included tumor regression grade, tumor volume reduction rate, and toxicity. Results: Seventy-one patients completed the planned preoperative CRT and surgery. Downstaging occurred in 20 (28.2%) patients, including 1 (1.4%) with a pathologic complete response. Favorable tumor regression (grade 4-3) was observed in 4 (5.6%) patients, and the mean tumor volume reduction rate was 62.5 ± 21.3%. Severe (grade ≥3) treatment toxicities were reported in 27 (38%) patients from CRT until 3 months after surgery. Conclusions: Preoperative short-course concurrent CRT followed by delayed surgery for patients with locally advanced rectal cancer demonstrated poor pathologic responses compared with conventional long-course CRT, and it yielded considerable toxicities despite the use of an advanced radiation therapy technique.

  16. Neutrophil depletion in the early inflammatory phase delayed cutaneous wound healing in older rats: improvements due to the use of un-denatured camel whey protein.

    Science.gov (United States)

    Ebaid, Hossam

    2014-03-04

    While it is known that advanced age alters the recruitment of neutrophils during wound healing, thereby delaying the wound healing process, little is known about prolonged wound healing in advanced ages. Thus, we investigated the correlation of neutrophil recruitment with healing events, and the impact of whey protein (WP) on neutrophil activation. The animals were allocated into wounded young group, wounded older group and wounded older rats with daily treatment of WP at a dose of 100 mg/kg of body weight. Our results pointed to a marked deficiency in the number of neutrophils in the wounds of older rats, which was accompanied with impairment of the healing process. In the group of older rats, phagocytic activity, as tested by fluorescence microscopy, declined throughout the first 24 hours after wounding. Both the neutrophil number and the phagocytic activity recovered in older rats which received WP supplementation. Interestingly, WP was found to significantly up-regulate the MIP-1α and CINC-1 mRNA expression in old rats. On the other hand, the wound size in older rats was significantly higher than that in younger ones. Blood angiogenesis was also significantly delayed in the older group as opposed to the young rats. WP, however, was found to return these indices to normal levels in the older rats. Proliferation and epidermal migration of the keratinocytes and the collagen deposition were also returned to the normal rates. This data confirms the critical role of neutrophil recruitment in the early inflammatory phase of wound healing in older rats. In addition, WP protein was used to improve neutrophil function in older rats, healing events returned to a more normal profile. The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2100966986117779.

  17. Alcohol Intake Increases in Adolescent C57BL/6J Mice during Intermittent Cycles of Phase-Delayed, Long-Light Conditions

    Directory of Open Access Journals (Sweden)

    Joshua J. Gamsby

    2017-08-01

    Full Text Available Adolescents naturally go to bed and awaken late, but are forced to awaken early for school and work. This leads to “social jetlag”, a state of circadian desynchrony (CD, in which internal biological rhythms are out of sync with behavioral rhythms. CD is associated with increased alcohol intake in adults, but has been less well-studied in adolescents. The goal of this study was to model adolescent alcohol intake during similar CD conditions in male C57BL/6J mice. Free access alcohol intake, water intake and wheel-running activity were measured during a normal 12HR photoperiod or during alternating photoperiod (Experiment 1: 12 h light for 4 days followed by 18 h light for 3 days, with dark (activity onset delayed 9 h during the 18HR photoperiod; Experiment 2: 12 h light for 4 days followed by 6 h light for 3 days, with dark onset delayed 3 h during the 6HR photoperiod. In Experiment 1, CD produced a small but significant increase in the total alcohol intake per day as well as in intake in bouts, with the greatest increase over controls in the hours following the 6HR dark period. Additionally, the pattern of alcohol intake in bouts shifted to increase alcohol intake during the shorter dark period. In Experiment 2, the opposite effect occurred—the longer dark cycle led to lower alcohol drinking in the second half of the dark period. However, in Experiment 2, CD produced no significant changes in either total alcohol intake or alcohol intake in bouts. Conclusion: shifts in the light cycle that disrupt the regular pattern of day and night, and increase the length of the night phase, are sufficient to increase both drinking in bouts and restricted drinking in adolescent mice, modeling increased alcohol intake in adolescents during CD.

  18. Getting a Good Night's Sleep in Adolescence: Do Strategies for Coping With Stress Matter?

    Science.gov (United States)

    Matthews, Karen A; Hall, Martica H; Cousins, Jennifer; Lee, Laisze

    2016-01-01

    Getting a good night's sleep is challenging for adolescents because of early school start times and adolescents' substantial social and physical changes. We tested whether key indices of sleep health are associated with usual styles of coping with stress and interpersonal conflict in healthy black and white adolescents. Two hundred forty-two (57% female, 56% black) high school students completed daily sleep diaries, questionnaires, and actigraphy across a school week. Linear regression models tested associations, independent of race, gender, and other covariates. Students who reported using disengagement coping exhibited poor sleep health. They had shorter sleep duration, more fragmented sleep, delayed sleep, and increased daytime sleepiness. Unexpectedly, positive engagement coping was related to daytime sleepiness and delayed sleep, although not in models that included disengagement coping. Coping strategies may be an important influence on adolescent sleep. Future research should evaluate the antecedent-consequent relationships among coping, sleep, and stress.

  19. Sleep-Related Disorders in Children with Attention-Deficit Hyperactivity Disorder: Preliminary Results of a Full Sleep Assessment Study.

    Science.gov (United States)

    Miano, Silvia; Esposito, Maria; Foderaro, Giuseppe; Ramelli, Gian Paolo; Pezzoli, Valdo; Manconi, Mauro

    2016-11-01

    We present the preliminary results of a prospective case-control sleep study in children with a diagnosis of attention-deficit hyperactivity disorder (ADHD). A deep sleep assessment including sleep questionnaires, sleep habits, a video-polysomnographic recording with full high-density electroencephalography (EEG) and cardiorespiratory polygraphy, multiple sleep latency test, and 1-week actigraphic recording were performed to verify whether children with ADHD may be classified into one of the following five phenotypes: (1) hypoarousal state, resembling narcolepsy, which may be considered a "primary" form of ADHD; (2) delayed sleep onset insomnia; (3) sleep-disordered breathing; (4) restless legs syndrome and/or periodic limb movements; and (5) sleep epilepsy and/or EEG interictal epileptiform discharges. Fifteen consecutive outpatients with ADHD were recruited (two female, mean age 10.6 ± 2.2, age range 8-13.7 years) over 6 months. The narcolepsy-like sleep phenotype was observed in three children, the sleep onset insomnia phenotype was observed in one child, mild obstructive sleep apnea was observed in three children, sleep hyperkinesia and/or PLMs were observed in five children, while IEDs and or nocturnal epilepsy were observed in three children. Depending on the sleep phenotype, children received melatonin, iron supplementation, antiepileptic drugs, or stimulants. Our study further highlights the need to design an efficient sleep diagnostic algorithm for children with ADHD, thereby more accurately identifying cases in which a full sleep assessment is indicated. © 2016 John Wiley & Sons Ltd.

  20. Effect of exposure to evening light on sleep initiation in the elderly: a longitudinal analysis for repeated measurements in home settings.

    Science.gov (United States)

    Obayashi, Kenji; Saeki, Keigo; Iwamoto, Junko; Okamoto, Nozomi; Tomioka, Kimiko; Nezu, Satoko; Ikada, Yoshito; Kurumatani, Norio

    2014-05-01

    Epidemiologic data have demonstrated associations of sleep-onset insomnia with a variety of diseases, including depression, dementia, diabetes and cardiovascular diseases. Sleep initiation is controlled by the suprachiasmatic nucleus of the hypothalamus and endogenous melatonin, both of which are influenced by environmental light. Exposure to evening light is hypothesized to cause circadian phase delay and melatonin suppression before bedtime, resulting in circadian misalignment and sleep-onset insomnia; however, whether exposure to evening light disturbs sleep initiation in home settings remains unclear. In this longitudinal analysis of 192 elderly individuals (mean age: 69.9 years), we measured evening light exposure and sleep-onset latency for 4 days using a wrist actigraph incorporating a light meter and an accelerometer. Mixed-effect linear regression analysis for repeated measurements was used to evaluate the effect of evening light exposure on subsequent sleep-onset latency. The median intensity of evening light exposure and the median sleep-onset latency were 27.3 lux (interquartile range, 17.9-43.4) and 17 min (interquartile range, 7-33), respectively. Univariate models showed significant associations between sleep-onset latency and age, gender, daytime physical activity, in-bed time, day length and average intensity of evening and nighttime light exposures. In a multivariate model, log-transformed average intensity of evening light exposure was significantly associated with log-transformed sleep-onset latency independent of the former potential confounding factors (regression coefficient, 0.133; 95% CI, 0.020-0.247; p = 0.021). Day length and nighttime light exposure were also significantly associated with log-transformed sleep-onset latency (p = 0.001 and p < 0.001, respectively). In conclusion, exposure to evening light in home setting prolongs subsequent sleep-onset latency in the elderly.

  1. Sleep patterns and predictors of disturbed sleep in a large population of college students.

    Science.gov (United States)

    Lund, Hannah G; Reider, Brian D; Whiting, Annie B; Prichard, J Roxanne

    2010-02-01

    To characterize sleep patterns and predictors of poor sleep quality in a large population of college students. This study extends the 2006 National Sleep Foundation examination of sleep in early adolescence by examining sleep in older adolescents. One thousand one hundred twenty-five students aged 17 to 24 years from an urban Midwestern university completed a cross-sectional online survey about sleep habits that included the Pittsburgh Sleep Quality Index (PSQI), the Epworth Sleepiness Scale, the Horne-Ostberg Morningness-Eveningness Scale, the Profile of Mood States, the Subjective Units of Distress Scale, and questions about academic performance, physical health, and psychoactive drug use. Students reported disturbed sleep; over 60% were categorized as poor-quality sleepers by the PSQI, bedtimes and risetimes were delayed during weekends, and students reported frequently taking prescription, over the counter, and recreational psychoactive drugs to alter sleep/wakefulness. Students classified as poor-quality sleepers reported significantly more problems with physical and psychological health than did good-quality sleepers. Students overwhelmingly stated that emotional and academic stress negatively impacted sleep. Multiple regression analyses revealed that tension and stress accounted for 24% of the variance in the PSQI score, whereas exercise, alcohol and caffeine consumption, and consistency of sleep schedule were not significant predictors of sleep quality. These results demonstrate that insufficient sleep and irregular sleep-wake patterns, which have been extensively documented in younger adolescents, are also present at alarming levels in the college student population. Given the close relationships between sleep quality and physical and mental health, intervention programs for sleep disturbance in this population should be considered. Copyright 2010 Society for Adolescent Medicine. Published by Elsevier Inc. All rights reserved.

  2. Insufficient sleep in adolescents: causes and consequences.

    Science.gov (United States)

    Owens, Judith A; Weiss, Miriam R

    2017-08-01

    Insufficient sleep poses an important and complicated set of health risks in the adolescent population. Not only is deficient sleep (defined as both sleep duration inadequate to meet sleep needs and sleep timing misaligned with the body's circadian rhythms) at epidemic levels in this population, but the contributing factors are both complex and numerous and there are a myriad of negative physical and mental health, safety and performance consequences. Causes of inadequate sleep identified in this population include internal biological processes such as the normal shift (delay) in circadian rhythm that occurs in association with puberty and a developmentally-based slowing of the "sleep drive", and external factors including extracurricular activities, excessive homework load, evening use of electronic media, caffeine intake and early school start times. Consequences range from inattentiveness, reduction in executive functioning and poor academic performance to increased risk of obesity and cardio-metabolic dysfunction, mood disturbances which include increased suicidal ideation, a higher risk of engaging in health risk behaviors such as alcohol and substance use, and increased rates of car crashes, occupational injuries and sports-related injuries. In response to these concerns, a number of promising measures have been proposed to reduce the burden of adolescent sleep loss, including healthy sleep education for students and families, and later school start times to allow adolescents to obtain sufficient and appropriately-timed sleep.

  3. Delayed Ejaculation

    Science.gov (United States)

    ... cases, it is due to a combination of physical and psychological concerns. Psychological causes of delayed ejaculation include: Depression, anxiety or other mental health conditions Relationship problems due to stress, poor communication ...

  4. Delayed growth

    Science.gov (United States)

    ... Slow rate of growth; Retarded growth and development; Growth delay Images Toddler development References Cooke DW, Divall SA, Radovick S. Normal and aberrant growth in children. In: Melmed S, Polonsky KS, Larsen PR, ...

  5. Medicines for sleep

    Science.gov (United States)

    Benzodiazepines; Sedatives; Hypnotics; Sleeping pills; Insomnia - medicines; Sleep disorder - medicines ... are commonly used to treat allergies. While these sleep aids are not addictive, your body becomes used ...

  6. Pulsing blue light through closed eyelids: effects on acute melatonin suppression and phase shifting of dim light melatonin onset

    Directory of Open Access Journals (Sweden)

    Figueiro MG

    2014-12-01

    Full Text Available Mariana G Figueiro, Barbara Plitnick, Mark S Rea Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY, USA Abstract: Circadian rhythm disturbances parallel the increased prevalence of sleep disorders in older adults. Light therapies that specifically target regulation of the circadian system in principle could be used to treat sleep disorders in this population. Current recommendations for light treatment require the patients to sit in front of a bright light box for at least 1 hour daily, perhaps limiting their willingness to comply. Light applied through closed eyelids during sleep might not only be efficacious for changing circadian phase but also lead to better compliance because patients would receive light treatment while sleeping. Reported here are the results of two studies investigating the impact of a train of 480 nm (blue light pulses presented to the retina through closed eyelids on melatonin suppression (laboratory study and on delaying circadian phase (field study. Both studies employed a sleep mask that provided narrowband blue light pulses of 2-second duration every 30 seconds from arrays of light-emitting diodes. The results of the laboratory study demonstrated that the blue light pulses significantly suppressed melatonin by an amount similar to that previously shown in the same protocol at half the frequency (ie, one 2-second pulse every minute for 1 hour. The results of the field study demonstrated that blue light pulses given early in the sleep episode significantly delayed circadian phase in older adults; these results are the first to demonstrate the efficacy and practicality of light treatment by a sleep mask aimed at adjusting circadian phase in a home setting. Keywords: circadian phase, dim light melatonin onset, light through closed eyelids, blue light, sleep

  7. Property Analysis of the Real-Time Uncalibrated Phase Delay Product Generated by Regional Reference Stations and Its Influence on Precise Point Positioning Ambiguity Resolution

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    Yong Zhang

    2017-05-01

    Full Text Available The real-time estimation of the wide-lane and narrow-lane Uncalibrated Phase Delay (UPD of satellites is realized by real-time data received from regional reference station networks; The properties of the real-time UPD product and its influence on real-time precise point positioning ambiguity resolution (RTPPP-AR are experimentally analyzed according to real-time data obtained from the regional Continuously Operating Reference Stations (CORS network located in Tianjin, Shanghai, Hong Kong, etc. The results show that the real-time wide-lane and narrow-lane UPD products differ significantly from each other in time-domain characteristics; the wide-lane UPDs have daily stability, with a change rate of less than 0.1 cycle/day, while the narrow-lane UPDs have short-term stability, with significant change in one day. The UPD products generated by different regional networks have obvious spatial characteristics, thus significantly influencing RTPPP-AR: the adoption of real-time UPD products employing the sparse stations in the regional network for estimation is favorable for improving the regional RTPPP-AR up to 99%; the real-time UPD products of different regional networks slightly influence PPP-AR positioning accuracy. After ambiguities are successfully fixed, the real-time dynamic RTPPP-AR positioning accuracy is better than 3 cm in the plane and 8 cm in the upward direction.

  8. Sleep inertia, sleep homeostatic and circadian influences on higher-order cognitive functions.

    Science.gov (United States)

    Burke, Tina M; Scheer, Frank A J L; Ronda, Joseph M; Czeisler, Charles A; Wright, Kenneth P

    2015-08-01

    Sleep inertia, sleep homeostatic and circadian processes modulate cognition, including reaction time, memory, mood and alertness. How these processes influence higher-order cognitive functions is not well known. Six participants completed a 73-day-long study that included two 14-day-long 28-h forced desynchrony protocols to examine separate and interacting influences of sleep inertia, sleep homeostasis and circadian phase on higher-order cognitive functions of inhibitory control and selective visual attention. Cognitive performance for most measures was impaired immediately after scheduled awakening and improved during the first ~2-4 h of wakefulness (decreasing sleep inertia); worsened thereafter until scheduled bedtime (increasing sleep homeostasis); and was worst at ~60° and best at ~240° (circadian modulation, with worst and best phases corresponding to ~09:00 and ~21:00 hours, respectively, in individuals with a habitual wake time of 07:00 hours). The relative influences of sleep inertia, sleep homeostasis and circadian phase depended on the specific higher-order cognitive function task examined. Inhibitory control appeared to be modulated most strongly by circadian phase, whereas selective visual attention for a spatial-configuration search task was modulated most strongly by sleep inertia. These findings demonstrate that some higher-order cognitive processes are differentially sensitive to different sleep-wake regulatory processes. Differential modulation of cognitive functions by different sleep-wake regulatory processes has important implications for understanding mechanisms contributing to performance impairments during adverse circadian phases, sleep deprivation and/or upon awakening from sleep. © 2015 European Sleep Research Society.

  9. Behavioral symptoms and sleep problems in children with anxiety disorder.

    Science.gov (United States)

    Iwadare, Yoshitaka; Kamei, Yuichi; Usami, Masahide; Ushijima, Hirokage; Tanaka, Tetsuya; Watanabe, Kyota; Kodaira, Masaki; Saito, Kazuhiko

    2015-08-01

    Sleep disorders are frequently associated with childhood behavioral problems and mental illnesses such as anxiety disorder. To identify promising behavioral targets for pediatric anxiety disorder therapy, we investigated the associations between specific sleep and behavioral problems. We conducted retrospective reviews of 105 patients aged 4-12 years who met the DSM-IV criteria for primary diagnosis of generalized anxiety disorder (n = 33), separation anxiety disorder (n = 23), social phobia (n = 21), or obsessive compulsive disorder (n = 28). Sleep problems were evaluated using the Children's Sleep Habits Questionnaire (CSHQ) and behavioral problems by the Spence Children's Anxiety Scale, Oppositional Defiant Behavior Inventory (ODBI), and Depression Self-Rating Scale for Children. Depressive behavior was weakly correlated with CSHQ subscores for sleep onset delay and night waking but not with total sleep disturbance. Anxiety was correlated with bedtime resistance, night waking, and total sleep disturbance score. Oppositional defiance was correlated with bedtime resistance, daytime sleepiness, sleep onset delay, and most strongly with total sleep disturbance. On multiple regression analysis ODBI score had the strongest positive association with total sleep disturbance and the strongest negative association with total sleep duration. Sleep problems in children with anxiety disorders are closely related to anxiety and oppositional defiant symptoms. © 2015 Japan Pediatric Society.

  10. Sleeping to fuel the immune system: mammalian sleep and resistance to parasites

    Directory of Open Access Journals (Sweden)

    Opp Mark R

    2009-01-01

    Full Text Available Abstract Sleep is an enigma. Why animals forgo eating and reproducing, while potentially increasing their risk of predation remains unknown. Although some may question whether all animals sleep, it is clear that all living organisms possess defenses against attack by pathogens. Immune responses of humans and animals are impaired by sleep loss, and responses to immune challenge include altered sleep. Thus, sleep is hypothesized to be a component of the acute phase response to infection and to function in host defense. Examining phylogenetic relationships among sleep parameters, components of the mammalian immune system and resistance to infection may provide insight into the evolution of sleep and lead to a greater appreciation for the role of sleep in host defense.

  11. Human Adolescent Phase Response Curves to Bright White Light.

    Science.gov (United States)

    Crowley, Stephanie J; Eastman, Charmane I

    2017-08-01

    Older adolescents are particularly vulnerable to circadian misalignment and sleep restriction, primarily due to early school start times. Light can shift the circadian system and could help attenuate circadian misalignment; however, a phase response curve (PRC) to determine the optimal time for receiving light and avoiding light is not available for adolescents. We constructed light PRCs for late pubertal to postpubertal adolescents aged 14 to 17 years. Participants completed 2 counterbalanced 5-day laboratory sessions after 8 or 9 days of scheduled sleep at home. Each session included phase assessments to measure the dim light melatonin onset (DLMO) before and after 3 days of free-running through an ultradian light-dark (wake-sleep) cycle (2 h dim [~20 lux] light, 2 h dark). In one session, intermittent bright white light (~5000 lux; four 20-min exposures) was alternated with 10 min of dim room light once per day for 3 consecutive days. The time of light varied among participants to cover the 24-h day. For each individual, the phase shift to bright light was corrected for the free-run derived from the other laboratory session with no bright light. One PRC showed phase shifts in response to light start time relative to the DLMO and another relative to home sleep. Phase delay shifts occurred around the hours corresponding to home bedtime. Phase advances occurred during the hours surrounding wake time and later in the afternoon. The transition from delays to advances occurred at the midpoint of home sleep. The adolescent PRCs presented here provide a valuable tool to time bright light in adolescents.

  12. Effects of Acute Sleep Deprivation Resulting from Night Shift Work on Young Doctors.

    Science.gov (United States)

    Sanches, Inês; Teixeira, Fátima; dos Santos, José Moutinho; Ferreira, António Jorge

    2015-01-01

    To evaluate sleep deprivation and its effects on young physicians in relation to concentration capacity and psychomotor performance. Eighteen physicians aged 26 - 33 years were divided into 2 groups: non-sleep deprived group (with no night work) and sleep deprived group (minimum 12 hour of night work/week). We applied Pittsburgh Sleep Quality Index to screen the presence of sleep pathology and Epworth Sleepiness Scale to evaluate subjective daytime sleepiness; we used actigraphy and sleep diary to assess sleep hygiene and standard sleep-wake cycles. To demonstrate the effects of sleep deprivation, we applied Toulouse-Piéron's test (concentration test) and a battery of three reaction time tasks after the night duty. Sleep deprived group had higher daytime sleepiness on Epworth Sleepiness Scale (p sleep deprivation was higher (p sleep during the period of night duty was 184.2 minutes to sleep deprived group and 397.7 minutes to non-sleep deprived group (p sleep deprived group had more omissions (p Sleep deprived group; in reaction to instruction test the sleep deprived group showed worse perfection index (p sleep deprivation resulting from nocturnal work in medical professions is associated with a reduction in attention and concentration and delayed response to stimuli. This may compromise patient care as well as the physician's health and quality of life. It is essential to study the effects of acute sleep deprivation on the cognitive abilities and performance of health professionals.

  13. Shiftwork-Mediated Disruptions of Circadian Rhythms and Sleep Homeostasis Cause Serious Health Problems

    Directory of Open Access Journals (Sweden)

    Suliman Khan

    2018-01-01

    Full Text Available Shiftwork became common during the last few decades with the growing demands of human life. Despite the social inactivity and irregularity in habits, working in continuous irregular shifts causes serious health issues including sleep disorders, psychiatric disorders, cancer, and metabolic disorders. These health problems arise due to the disruption in circadian clock system, which is associated with alterations in genetic expressions. Alteration in clock controlling genes further affects genes linked with disorders including major depression disorder, bipolar disorder, phase delay and phase advance sleep syndromes, breast cancer, and colon cancer. A diverse research work is needed focusing on broad spectrum changes caused by jet lag in brain and neuronal system. This review is an attempt to motivate the researchers to conduct advanced studies in this area to identify the risk factors and mechanisms. Its goal is extended to make the shift workers aware about the risks associated with shiftwork.

  14. Healthy Sleep

    Science.gov (United States)

    ... quality sleep, ask yourself Do you have trouble getting up in the morning? Do you have trouble focusing during the day? Do you doze off during the day? If you answered yes to these three questions, you should work on ...

  15. Pediatric sleep apnea

    Science.gov (United States)

    Sleep apnea - pediatric; Apnea - pediatric sleep apnea syndrome; Sleep-disordered breathing - pediatric ... Untreated pediatric sleep apnea may lead to: High blood pressure Heart or lung problems Slow growth and development

  16. Changing your sleep habits

    Science.gov (United States)

    ... falling asleep; Sleep hygiene References American Academy of Sleep Medicine. Insomnia. Updated March 4, 2015. SleepEducation.org. sleepeducation. ... T, Dement WC, eds. Principles and Practice of Sleep Medicine . 6th ed. Philadelphia, PA: Elsevier; 2017:chap 86. ...

  17. Obstructive Sleep Apnoea

    African Journals Online (AJOL)

    Cheyne-Stokes respiration), obstructive sleep apnoea and mixed or complex sleep apnoea.1. Obstructive sleep apnoea (OSA) is the most common of these three disorders and is defined as airway obstruction during sleep, accompanied by at least ...

  18. Snoring and Sleep Apnea

    Science.gov (United States)

    ... Find an ENT Doctor Near You Snoring and Sleep Apnea Snoring and Sleep Apnea Patient Health Information ... newsroom@entnet.org . Insight into sleeping disorders and sleep apnea Forty-five percent of normal adults snore ...

  19. Sleep-time sizing and scheduling in green passive optical networks

    KAUST Repository

    Elrasad, Amr; Khafagy, Mohammad G.; Shihada, Basem

    2012-01-01

    of traffic, control and data. Control traffic are delay intolerant with higher priority than the data traffic. Closed form model for average ONU sleeping time and end-to-end data traffic delay are presented and evaluated. Our framework decouples

  20. Sleep Habits of Elementary and Middle School Children in South Texas.

    Science.gov (United States)

    Surani, Salim; Hesselbacher, Sean; Surani, Saherish; Sadasiva, Sreevidya; Surani, Zoya; Surani, Sara S; Khimani, Amina; Subramanian, Shyam

    2015-01-01

    Background. Sleep difficulties, including insufficient sleep and inadequate sleep hygiene, have been prevalent among children. Sleep deprivation can lead to poor grades, sleepiness, and moodiness. We undertook this study to assess the prevalence of sleep abnormalities among elementary and middle school students in South Texas and how the groups compare with one another. Method. After approval from the appropriate school district for a sleep education program, a baseline survey was taken of elementary and middle school students, using the Children's Sleep Habit Questionnaire-Sleep Self-Report Form, which assessed the domains of bedtime resistance, sleep onset delay, sleep anxiety, sleep duration, night awakening, and daytime sleepiness. Results. The survey was completed by 499 elementary and 1008 middle school children. Trouble sleeping was reported by 43% in elementary school, compared with 29% of middle school children. Fifty percent of middle school children did not like sleeping, compared with 26% in elementary school. Bedtime resistance, sleep onset delay, and nighttime awakening were more common among elementary school students. Daytime sleepiness was more common among the middle school children when compared to elementary school children. Conclusions. Sleep abnormalities are present in elementary school children with changes in sleep habits into middle school.

  1. Sleep Habits of Elementary and Middle School Children in South Texas

    Directory of Open Access Journals (Sweden)

    Salim Surani

    2015-01-01

    Full Text Available Background. Sleep difficulties, including insufficient sleep and inadequate sleep hygiene, have been prevalent among children. Sleep deprivation can lead to poor grades, sleepiness, and moodiness. We undertook this study to assess the prevalence of sleep abnormalities among elementary and middle school students in South Texas and how the groups compare with one another. Method. After approval from the appropriate school district for a sleep education program, a baseline survey was taken of elementary and middle school students, using the Children’s Sleep Habit Questionnaire-Sleep Self-Report Form, which assessed the domains of bedtime resistance, sleep onset delay, sleep anxiety, sleep duration, night awakening, and daytime sleepiness. Results. The survey was completed by 499 elementary and 1008 middle school children. Trouble sleeping was reported by 43% in elementary school, compared with 29% of middle school children. Fifty percent of middle school children did not like sleeping, compared with 26% in elementary school. Bedtime resistance, sleep onset delay, and nighttime awakening were more common among elementary school students. Daytime sleepiness was more common among the middle school children when compared to elementary school children. Conclusions. Sleep abnormalities are present in elementary school children with changes in sleep habits into middle school.

  2. Sleep in Othello

    Science.gov (United States)

    Dimsdale, Joel E.

    2009-01-01

    Some of our best descriptions of sleep disorders come from literature. While Shakespeare is well known for his references to insomnia and sleep walking, his works also demonstrate a keen awareness of many other sleep disorders. This paper examines sleep themes in Shakespeare's play Othello. The play indicates Shakespeare's astute eye for sleep deprivation, sexual parasomnias, and effects of stress and drugs on sleep. Citation: Dimsdale JE. Sleep in Othello. J Clin Sleep Med 2009;5(3):280-281. PMID:19960651

  3. Sleep Tips: 7 Steps to Better Sleep

    Science.gov (United States)

    ... turn every night. Consider simple tips for better sleep, from setting a sleep schedule to including physical activity in your daily ... factors that can interfere with a good night's sleep — from work stress and family responsibilities to unexpected ...

  4. Sleep in Othello

    OpenAIRE

    Dimsdale, Joel E.

    2009-01-01

    Some of our best descriptions of sleep disorders come from literature. While Shakespeare is well known for his references to insomnia and sleep walking, his works also demonstrate a keen awareness of many other sleep disorders. This paper examines sleep themes in Shakespeare's play Othello. The play indicates Shakespeare's astute eye for sleep deprivation, sexual parasomnias, and effects of stress and drugs on sleep.

  5. Sleep habits in adolescents of Saudi Arabia; distinct patterns and extreme sleep schedules.

    Science.gov (United States)

    Merdad, Roah A; Merdad, Leena A; Nassif, Rawan A; El-Derwi, Douaa; Wali, Siraj O

    2014-11-01

    There is a need for comprehensive studies on adolescents' sleep habits in the Middle Eastern region. The aim of this study was to investigate the sleep-wake patterns, prevalence of excessive daytime sleepiness (EDS), and disturbed sleep among adolescents in Saudi Arabia and to identify the associated factors. The study was a cross-sectional survey done on a random sample of 1035 high school students, ages 14-23 years, in Jeddah, Saudi Arabia. The response rate was 91%. Students filled a self-reported questionnaire that included sleep-wake questions, Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, Perceived Stress Scale, academic performance, and personal data. Students slept an average of 7.0 hours on school nights, with an average delay of 2.8 and 6.0 hours in weekend sleep and rise times, respectively. Around 1 in 10 students stayed up all night and slept after returning from school (exhibiting a reversed sleep cycle) on weeknights. This pattern was more prevalent among boys and students with lower grade point averages. The prevalence of sleep disturbance was 65%, and EDS was found in 37% of the students. Predictors of EDS were school type, stress, napping and caffeine use, while gender was a predictor of disturbed sleep. Adolescents in Saudi Arabia showed a high percentage of poor sleep quality. Compared with adolescents from other countries, they had a larger delay in weekend sleep and rise times. An alarming reversed sleep cycle on weekdays is present and highlights the need for further assessment. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Improved Visibility of Metastatic Disease in the Liver During Intra-Arterial Therapy Using Delayed Arterial Phase Cone-Beam CT

    Energy Technology Data Exchange (ETDEWEB)

    Schernthaner, Ruediger E., E-mail: ruediger.schernthaner@meduniwien.ac.at [Medical University of Vienna, Section of Cardiovascular and Interventional Radiology, Department of Biomedical Imaging and Image-guided Therapy (Austria); Haroun, Reham R., E-mail: rehamharoun1989@gmail.com; Duran, Rafael, E-mail: rafaelduran.md@gmail.com; Lee, Howard, E-mail: mail2howielee@gmail.com; Sahu, Sonia, E-mail: sonia.p.sahu@gmail.com; Sohn, Jae Ho, E-mail: sohn87@gmail.com; Chapiro, Julius, E-mail: j.chapiro@googlemail.com; Zhao, Yan, E-mail: yanzhao211@163.com; Gorodetski, Boris, E-mail: boris.gorodetski@charite.de; Fleckenstein, Florian, E-mail: florian.fleckenstein@charite.de; Smolka, Susanne, E-mail: susanne.smolka@charite.de [Yale University School of Medicine, Department of Radiology and Biomedical Imaging (United States); Radaelli, Alessandro, E-mail: Alessandro.Radaelli@philips.com; Bom, Imramsjah Martijn van der, E-mail: martijn.van.der.bom@philips.com [Philips Healthcare, Image-Guided Therapy Systems (Netherlands); Lin, MingDe, E-mail: ming.lin@philips.com; Geschwind, Jean Francois, E-mail: jeff.geschwind@yale.edu [Yale University School of Medicine, Department of Radiology and Biomedical Imaging (United States)

    2016-10-15

    PurposeTo compare the visibility of liver metastases on dual-phase cone-beam CT (DP-CBCT) and digital subtraction angiography (DSA), with reference to preinterventional contrast-enhanced magnetic resonance imaging (CE-MRI) of the liver.MethodsThis IRB-approved, retrospective study included 28 patients with neuroendocrine (NELM), colorectal (CRCLM), or sarcoma (SLM) liver metastases who underwent DP-CBCT during intra-arterial therapy (IAT) between 01/2010 and 10/2014. DP-CBCT was acquired after a single contrast agent injection in the tumor-feeding arteries at early and delayed arterial phases (EAP and DAP). The visibility of each lesion was graded by two radiologists in consensus on a three-rank scale (complete, partial, none) on DP-CBCT and DSA images using CE-MRI as reference.Results47 NELM, 43 CRCLM, and 16 SLM were included. On DSA 85.1, 44.1, and 37.5 % of NELM, CRCLM, and SLM, were at least partially depicted, respectively. EAP-CBCT yielded significantly higher sensitivities of 88.3 and 87.5 % for CRCLM and SLM, respectively (p < 0.01), but not for NELM (89.4 %; p = 1.0). On DAP-CBCT all NELM, CRCLM, and SLM were visible (p < 0.001). Complete depiction was achieved on DSA for 59.6, 16.3, and 18.8 % of NELM, CRCLM, and SLM, respectively. The complete depiction rate on EAP-CBCT was significantly higher for CRCLM (46.5 %; p < 0.001), lower for NELM (40.4 %; p = 0.592), and similar for SLM (25 %, p = 0.399). On DAP-CBCT however, the highest rates of complete depiction were found—NELM (97.8 %; p = 0.008), CRCLM (95.3 %; p = 0.008), and SLM (100 %; p < 0.001).ConclusionDAP-CBCT substantially improved the visibility of liver metastases during IAT. Future studies need to evaluate the clinical impact.

  7. [Sleep habits, sleep quality and sleep medicine use of the Swiss population result].

    Science.gov (United States)

    Tinguely, Gilberte; Landolt, Hans-Peter; Cajochen, Christian

    2014-11-01

    A survey in a representative sample of the Swiss population revealed an average sleep duration of 7.5 hours on workdays and of 8.5 hours on free days, which reflected a more than half an hour (38 min) shorter sleep duration than 28 years ago. The mean time in bed was between 22:41 and 06:37 on workdays and between 23:29 and 08:27 on free days. On workdays as well as on free days the bedtime was delayed by 47 minutes in comparison to a similar survey 28 years ago. By contrast, the mean rise times on workdays and free days did not change. The sleep duration required to feel refreshed was indicated with 7 hours, which was 41 minutes less than 28 years ago. Roughly 90 % of the interviewees answered that they felt healthy, and 75 % described their sleep as good or very good compared to 79 % 28 years ago. The most frequent reasons stated for bad sleep were personal problems and strain at the workplace. The effect of bad quality sleep on every day functioning was considered as essential by 65 % of the respondents compared to 69 % 28 years ago. The use of medication to improve sleep was declared by 2.8 % (2.7 % 28 years ago), most often benzodiazepines, but also Valerian products and so-called z-drugs. In comparison with similar surveys in other countries (France, Great Britain and USA), Swiss residents slept roughly half an hour longer, but these other countries alike showed a sizable shortening of their habitual sleep duration over the last decades.

  8. Developmental delay

    Science.gov (United States)

    Nutrition support is essential for the care of the child with developmental delay. After a thorough evaluation, an individualized intervention plan that accounts for the child’s nutrition status, feeding ability, and medical condition may be determined. Nutrition assessments may be performed at leas...

  9. Sleep disturbance and neuropsychological function in young children with ADHD.

    Science.gov (United States)

    Schneider, Heather E; Lam, Janet C; Mahone, E Mark

    2016-01-01

    Sleep disturbance, common among children with ADHD, can contribute to cognitive and behavioral dysfunction. It is therefore challenging to determine whether neurobehavioral dysfunction should be attributed to ADHD symptoms, sleep disturbance, or both. The present study examined parent-reported sleep problems (Children's Sleep Habits Questionnaire) and their relationship to neuropsychological function in 64 children, aged 4-7 years, with and without ADHD. Compared to typically developing controls, children with ADHD were reported by parents to have significantly greater sleep disturbance--including sleep onset delay, sleep anxiety, night awakenings, and daytime sleepiness--(all p ≤ .01), and significantly poorer performance on tasks of attention, executive control, processing speed, and working memory (all p sleep disturbance was significantly associated with deficits in attention and executive control skills (all p ≤ .01); however, significant group differences (relative to controls) on these measures remained (p sleep disturbance. While sleep problems are common among young children with ADHD, these findings suggest that inattention and executive dysfunction appear to be attributable to symptoms of ADHD rather than to sleep disturbance. The relationships among sleep, ADHD symptoms, and neurobehavioral function in older children may show different patterns as a function of the chronicity of disordered sleep.

  10. Sleep in Children With Autism Spectrum Disorders: How Are Measures of Parent Report and Actigraphy Related and Affected by Sleep Education?

    Science.gov (United States)

    Veatch, Olivia J; Reynolds, Ann; Katz, Terry; Weiss, Shelly K; Loh, Alvin; Wang, Lily; Malow, Beth A

    2016-01-01

    Sleep disturbance is common in children with autism, resulting in a great need for effective treatments. To evaluate treatments for sleep disturbance in this population, it is critical to understand the relationship between measures of sleep captured by parent report and objective measures. The Children's Sleep Habits Questionnaire (CSHQ) and actigraphy-measured data from 80 children with autism and sleep-onset delay were evaluated. Reported problems with sleep-onset delay were concurrent with sleep duration problems in 66% of children, night wakings in 72% of children, and bedtime resistance in 66% of children; 38% of children were reported to have problems with all CSHQ insomnia domains. Actigraphy-measured sleep duration was correlated with estimates using CSHQ-reported bed and wake times.

  11. Obstructive sleep apnoea syndrome in children

    Directory of Open Access Journals (Sweden)

    Anna Włodarska

    2016-09-01

    Full Text Available Sleep-related breathing disorders in children are a clinical problem which is more and more often diagnosed by doctors nowadays. They can be the basis for diagnosing obstructive sleep apnoea syndrome that causes a number of complications: lowering the quality of life, behavioural problems, complications involving cardiovascular system. The incidence of obstructive sleep apnoea syndrome in the paediatric population is estimated to be at the level of 2%. The symptoms of obstructive sleep apnoea syndrome can be divided into daytime and night ones. Night symptoms in children include: snoring, apnoea, breathing with open mouth (both during the day and at night, dry tongue and mouth during sleep, agitated sleep in unnatural positions. Among daytime symptoms of obstructive sleep apnoea syndrome there are: irritability, aggressiveness, hyperactivity, attention deficit disorder, delayed development and growth pattern (mainly failure to thrive, learning problems, morning headaches. Parents often do not connect the night and daytime symptoms with the possible development of obstructive sleep apnoea syndrome in their children. The main predisposing factor of obstructive sleep apnoea syndrome in children is adenotonsillar hypertrophy. Effective and in most cases preferred treatment for the management of obstructive sleep apnoea syndrome in children is adenotonsillectomy. Polysomnography and polygraphy are diagnostic tools helpful in the study of sleep-related disorders. The objective of this study was to systematise the knowledge on the epidemiology, aetiology, clinical image and prevention of obstructive sleep apnoea syndrome in children.

  12. Time Delay of CGM Sensors

    Science.gov (United States)

    Schmelzeisen-Redeker, Günther; Schoemaker, Michael; Kirchsteiger, Harald; Freckmann, Guido; Heinemann, Lutz; del Re, Luigi

    2015-01-01

    Background: Continuous glucose monitoring (CGM) is a powerful tool to support the optimization of glucose control of patients with diabetes. However, CGM systems measure glucose in interstitial fluid but not in blood. Rapid changes in one compartment are not accompanied by similar changes in the other, but follow with some delay. Such time delays hamper detection of, for example, hypoglycemic events. Our aim is to discuss the causes and extent of time delays and approaches to compensate for these. Methods: CGM data were obtained in a clinical study with 37 patients with a prototype glucose sensor. The study was divided into 5 phases over 2 years. In all, 8 patients participated in 2 phases separated by 8 months. A total number of 108 CGM data sets including raw signals were used for data analysis and were processed by statistical methods to obtain estimates of the time delay. Results: Overall mean (SD) time delay of the raw signals with respect to blood glucose was 9.5 (3.7) min, median was 9 min (interquartile range 4 min). Analysis of time delays observed in the same patients separated by 8 months suggests a patient dependent delay. No significant correlation was observed between delay and anamnestic or anthropometric data. The use of a prediction algorithm reduced the delay by 4 minutes on average. Conclusions: Prediction algorithms should be used to provide real-time CGM readings more consistent with simultaneous measurements by SMBG. Patient specificity may play an important role in improving prediction quality. PMID:26243773

  13. Sleep Patterns in Chinese Preschool Children: A Population-Based Study.

    Science.gov (United States)

    Wu, Ran; Wang, Guang-Hai; Zhu, Hong; Jiang, Fan; Jiang, Chun-Lei

    2018-04-15

    This study aimed to (1) provide data on normal sleep patterns in Chinese preschool children, (2) identify cross-cultural differences of sleep patterns among children from China and other countries, (3) estimate the prevalence of sleep duration not meeting the optimal amount, and (4) characterize delayed weekend sleep pattern. A population-based sample of 1,610 children aged 3-6 years was recruited from 10 cities across China. Parents completed questions about their child's sleep patterns adapted from the Children's Sleep Habits Questionnaire (CSHQ). The mean bedtime was 9:31 PM, wake time was 7:27 AM, nighttime sleep duration was 9 hours 30 minutes, daytime sleep duration was 1 hour 31 minutes, and total sleep duration was 11 hours 2 minutes. The children had a shorter nighttime sleep duration but longer daytime naps, resulting in no differences in total sleep duration compared with counterparts predominantly in the west. Of the children, 85.3% met the recommended amount of sleep of 10 to 13 hours, and 10.8% slept fewer than 10 hours. The prevalence of sleep less than 10 hours was higher in older children and children from eastern China. Children went to bed and woke up more than 30 minutes later on weekends than weekdays, accounting for 40.1% and 50%, respectively. Children in western China showed longer delay than children in eastern China ( P < .05). Age- and region-specific variability of sleep patterns are reported as well as insufficient sleep and delayed weekend sleep pattern in Chinese preschool children. The cross-cultural difference of sleep patterns was in temporal placement rather than sleep duration. © 2018 American Academy of Sleep Medicine.

  14. Parent-Based Sleep Education for Children with Autism Spectrum Disorders

    Science.gov (United States)

    Malow, Beth A.; Adkins, Karen W.; Reynolds, Ann; Weiss, Shelly K.; Loh, Alvin; Fawkes, Diane; Katz, Terry; Goldman, Suzanne E.; Madduri, Niru; Hundley, Rachel; Clemons, Traci

    2014-01-01

    This study provided sleep education to parents of children with autism spectrum disorder (ASD) to determine whether an individual or group format was more effective in improving sleep and aspects of daytime behavior and family functioning. Eighty children, ages 2-10 years, with ASD and sleep onset delay completed the study. Actigraphy and parent…

  15. Later Start, Longer Sleep: Implications of Middle School Start Times

    Science.gov (United States)

    Temkin, Deborah A.; Princiotta, Daniel; Ryberg, Renee; Lewin, Daniel S.

    2018-01-01

    Background: Although adolescents generally get less than the recommended 9 hours of sleep per night, research and effort to delay school start times have generally focused on high schools. This study assesses the relation between school start times and sleep in middle school students while accounting for potentially confounding demographic…

  16. Sleep Disturbances in Newborns

    OpenAIRE

    Yasova Barbeau, Daphna; Weiss, Michael D.

    2017-01-01

    The purpose of this review is to serve as an introduction to understanding sleep in the fetus, the preterm neonate and the term neonate. Sleep appears to have numerous important roles, particularly in the consolidation of new information. The sleep cycle changes over time, neonates spend the most time in active sleep and have a progressive shortening of active sleep and lengthening of quiet sleep. Additionally, the sleep cycle is disrupted by many things including disease state and environmen...

  17. Contrast enhanced liver MRI in patients with primary sclerosing cholangitis: inverse appearance of focal confluent fibrosis on delayed phase MR images with hepatocyte specific versus extracellular gadolinium based contrast agents.

    Science.gov (United States)

    Husarik, Daniela B; Gupta, Rajan T; Ringe, Kristina I; Boll, Daniel T; Merkle, Elmar M

    2011-12-01

    To assess the enhancement pattern of focal confluent fibrosis (FCF) on contrast-enhanced hepatic magnetic resonance imaging (MRI) using hepatocyte-specific (Gd-EOB-DTPA) and extracellular (ECA) gadolinium-based contrast agents in patients with primary sclerosing cholangitis (PSC). After institutional review board approval, 10 patients with PSC (6 male, 4 female; 33-61 years) with 13 FCF were included in this retrospective study. All patients had a Gd-EOB-DTPA-enhanced liver MRI exam, and a comparison ECA-enhanced MRI. On each T1-weighted dynamic dataset, the signal intensity (SI) of FCF and the surrounding liver as well as the paraspinal muscle (M) were measured. In the Gd-EOB-DTPA group, hepatocyte phase images were also included. SI FCF/SI M, SI liver/SI M, and [(SI liver - SI FCF)/SI liver] were compared between the different contrast agents for each dynamic phase using the paired Student's t-test. There was no significant difference in SI FCF/SI M in all imaging phases. SI liver/SI M was significantly higher for the Gd-EOB-DTPA group in the delayed phase (P DTPA group, mean [(SI liver - SI FCF)/SI liver] were as follows (values for ECA group in parentheses): unenhanced phase: 0.26 (0.26); arterial phase: 0.01 (-0.31); portal venous phase (PVP): -0.05 (-0.26); delayed phase (DP): 0.14 (-0.54); and hepatocyte phase: 0.26. Differences were significant for the DP (P DTPA-enhanced images. Copyright © 2011 AUR. Published by Elsevier Inc. All rights reserved.

  18. Sleep Applications to Assess Sleep Quality.

    Science.gov (United States)

    Fietze, Ingo

    2016-12-01

    This article highlights the potential uses that smartphone applications may have for helping those with sleep problems. Applications in smartphones offer the promised possibility of detection of sleep. From the author's own experience, one can also conclude that sleep applications are approximately as good as polysomnography in detection of sleep time, similar to the conventional wearable actimeters. In the future, sleep applications will help to further enhance awareness of sleep health and to distinguish those who actually poorly and only briefly sleep from those who suffer more likely from paradox insomnia. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Fiber and Saturated Fat Are Associated with Sleep Arousals and Slow Wave Sleep.

    Science.gov (United States)

    St-Onge, Marie-Pierre; Roberts, Amy; Shechter, Ari; Choudhury, Arindam Roy

    2016-01-01

    Sleep restriction alters food intake, but less is known about how dietary patterns affect sleep. Current goals were to determine whether: (1) sleep is different after consumption of a controlled diet vs. an ad libitum diet, and (2) dietary intake during ad libitum feeding is related to nocturnal sleep. Twenty-six normal weight adults (30-45 y), habitually sleeping 7-9 h/night, participated in a randomized-crossover inpatient study with 2 phases of 5 nights: short (4 h in bed) or habitual (9 h in bed) sleep. Only data from the habitual sleep phase were used for the present analyses. During the first 4 days, participants consumed a controlled diet; on day 5, food intake was self-selected. Linear regression was used to determine relations between daytime food intake and nighttime sleep on day 5. Sleep duration did not differ after 3 days of controlled feeding vs. a day of ad libitum intake. However, sleep after ad libitum eating had less slow wave sleep (SWS, P = 0.0430) and longer onset latency (P = 0.0085). Greater fiber intake predicted less stage 1 (P = 0.0198) and more SWS (P = 0.0286). Percent of energy from saturated fat predicted less SWS (P = 0.0422). Higher percent of energy from sugar and other carbohydrates not considered sugar or fiber was associated with arousals (P = 0.0320 and 0.0481, respectively). Low fiber and high saturated fat and sugar intake is associated with lighter, less restorative sleep with more arousals. Diet could be useful in the management of sleep disorders but this needs to be tested. http://www.clinicaltrials.gov, #NCT00935402. © 2016 American Academy of Sleep Medicine.

  20. Time-Delay Interferometry

    Directory of Open Access Journals (Sweden)

    Massimo Tinto

    2014-08-01

    Full Text Available Equal-arm detectors of gravitational radiation allow phase measurements many orders of magnitude below the intrinsic phase stability of the laser injecting light into their arms. This is because the noise in the laser light is common to both arms, experiencing exactly the same delay, and thus cancels when it is differenced at the photo detector. In this situation, much lower level secondary noises then set the overall performance. If, however, the two arms have different lengths (as will necessarily be the case with space-borne interferometers, the laser noise experiences different delays in the two arms and will hence not directly cancel at the detector. In order to solve this problem, a technique involving heterodyne interferometry with unequal arm lengths and independent phase-difference readouts has been proposed. It relies on properly time-shifting and linearly combining independent Doppler measurements, and for this reason it has been called time-delay interferometry (TDI. This article provides an overview of the theory, mathematical foundations, and experimental aspects associated with the implementation of TDI. Although emphasis on the application of TDI to the Laser Interferometer Space Antenna (LISA mission appears throughout this article, TDI can be incorporated into the design of any future space-based mission aiming to search for gravitational waves via interferometric measurements. We have purposely left out all theoretical aspects that data analysts will need to account for when analyzing the TDI data combinations.

  1. [Habits and problems of sleep in adolescent students].

    Science.gov (United States)

    Lazaratou, E; Dikeos, D; Anagnostopoulos, D; Soldatos, C

    2008-07-01

    The evaluation of sleep habits and sleep related problems in high school adolescent students in the Athens area and the assessment of these problems' relation to demographic and other variables was investigated by the Athens Insomnia Scale - 5 item version (AIS-5), which was administered to 713 adolescent Senior High School students in the Greater Athens Area. Data such as age, sex, school records, and time spent per week in school-related and extracurricular activities were collected. The sample's mean sleep duration was 7,5 hours, mean bedtime 12:20 am and wake-up time 7:15 am. Total sleep time was not affected by gender, but was influenced by time spent in various activities. Sleep complaints were related to delayed sleep, onset latency and insufficient total duration of sleep. Girls complained more than boys, while correlations showed that students with lower academic per formance and those in second grade were more likely to have higher AIS-5 scores. The results show that sleep time of high school students is dependent on practical matters such as school schedule and other activities, while sleep complaints are related to female gender, bad school performance as well as to the second grade. The difference between actual sleep time and sleep complaints should be considered when studying the sleep of adolescents.

  2. A global quantification of "normal" sleep schedules using smartphone data.

    Science.gov (United States)

    Walch, Olivia J; Cochran, Amy; Forger, Daniel B

    2016-05-01

    The influence of the circadian clock on sleep scheduling has been studied extensively in the laboratory; however, the effects of society on sleep remain largely unquantified. We show how a smartphone app that we have developed, ENTRAIN, accurately collects data on sleep habits around the world. Through mathematical modeling and statistics, we find that social pressures weaken and/or conceal biological drives in the evening, leading individuals to delay their bedtime and shorten their sleep. A country's average bedtime, but not average wake time, predicts sleep duration. We further show that mathematical models based on controlled laboratory experiments predict qualitative trends in sunrise, sunset, and light level; however, these effects are attenuated in the real world around bedtime. Additionally, we find that women schedule more sleep than men and that users reporting that they are typically exposed to outdoor light go to sleep earlier and sleep more than those reporting indoor light. Finally, we find that age is the primary determinant of sleep timing, and that age plays an important role in the variability of population-level sleep habits. This work better defines and personalizes "normal" sleep, produces hypotheses for future testing in the laboratory, and suggests important ways to counteract the global sleep crisis.

  3. Female impulsive aggression: a sleep research perspective.

    Science.gov (United States)

    Lindberg, Nina; Tani, Pekka; Putkonen, Hanna; Sailas, Eila; Takala, Pirjo; Eronen, Markku; Virkkunen, Matti

    2009-01-01

    The rate of violent crimes among girls and women appears to be increasing. One in every five female prisoners has been reported to have antisocial personality disorder. However, it has been quite unclear whether the impulsive, aggressive behaviour among women is affected by the same biological mechanisms as among men. Psychiatric sleep research has attempted to identify diagnostically sensitive and specific sleep patterns associated with particular disorders. Most psychiatric disorders are typically characterized by a severe sleep disturbance associated with decreased amounts of slow wave sleep (SWS), the physiologically significant, refreshing part of sleep. Among men with antisocial behaviour with severe aggression, on the contrary, increased SWS has been reported, reflecting either specific brain pathology or a delay in the normal development of human sleep patterns. In our preliminary study among medication-free, detoxified female homicidal offenders with antisocial personality disorder, the same profound abnormality in sleep architecture was found. From the perspective of sleep research, the biological correlates of severe impulsive aggression seem to share similar features in both sexes.

  4. Sleep walking

    Science.gov (United States)

    ... Sleepwalking. In: Chokroverty S, Thomas RJ, eds. Atlas of Sleep Medicine . 2nd ed. Philadelphia, PA: Elsevier Saunders; 2014:380- ... of Clinical Neurology, SUNY Stony Brook, School of Medicine, Stony Brook, NY. Review provided by VeriMed Healthcare ... NIH MedlinePlus Magazine Read more ...

  5. Tasimelteon for non-24-hour sleep-wake disorder in totally blind people (SET and RESET): two multicentre, randomised, double-masked, placebo-controlled phase 3 trials.

    Science.gov (United States)

    Lockley, Steven W; Dressman, Marlene A; Licamele, Louis; Xiao, Changfu; Fisher, Dennis M; Flynn-Evans, Erin E; Hull, Joseph T; Torres, Rosarelis; Lavedan, Christian; Polymeropoulos, Mihael H

    2015-10-31

    Most totally blind people have non-24-hour sleep-wake disorder (non-24), a rare circadian rhythm disorder caused by an inability of light to reset their circadian pacemaker. In two consecutive placebo-controlled trials (SET and RESET), we assessed safety and efficacy (in terms of circadian entrainment and maintenance) of once-daily tasimelteon, a novel dual-melatonin receptor agonist. We undertook the placebo-controlled, randomised, double-masked trials in 27 US and six German clinical research centres and sleep centres. We screened totally blind adults (18-75 years of age), who were eligible for the randomisation phase of SET if they had a non-24-hour circadian period (τ) of 24·25 h or longer (95% CI greater than 24·0 and up to 24·9 h), as calculated from measurements of urinary 6-sulphatoxymelatonin rhythms. For SET, we used block randomisation to assign patients (1:1) to receive tasimelteon (20 mg) or placebo every 24 h at a fixed clock time 1 h before target bedtime for 26 weeks. Patients who entered the open-label group receiving tasimelteon in SET or who did not meet the SET inclusion criteria but did meet the RESET inclusion criteria were screened for RESET. A subset of the patients who entered the open-label group before the RESET study and who had eligible τ values were screened for RESET after completing the open-label treatment. In RESET, we withdrew tasimelteon in a randomised manner (1:1) in patients who responded (ie, entrained) after a tasimelteon run-in period. Entrainment was defined as having τ of 24·1 h or less and a 95% CI that included 24·0 h. In SET, the primary endpoint was the proportion of entrained patients, assessed in the intention-to-treat population. The planned step-down primary endpoint assessed the proportion of patients who had a clinical response (entrainment at month 1 or month 7 plus clinical improvement, measured by the Non-24 Clinical Response Scale). In RESET, the primary endpoint was the proportion of non

  6. Brainwave entrainment for better sleep and post-sleep state of young elite soccer players - a pilot study.

    Science.gov (United States)

    Abeln, Vera; Kleinert, Jens; Strüder, Heiko K; Schneider, Stefan

    2014-01-01

    The effect of sleep deprivation on psychophysical performance and well-being is comprehensively investigated. Research investigating the effect of improved sleep is rare. Just as little exists about attempts to support athletic mental state and performance by improving sleep quality. This study aims to investigate whether sleep quality of top athletes can be improved by auditory brainwave entrainment and whether this leads to enhancements of post-sleep psychophysical states. In a pilot study, 15 young elite soccer players were stimulated for eight weeks during sleep with binaural beats around 2-8 Hz. Once a week after wake-up, participants completed three different questionnaires: a sleep diary, an adjective list for psychophysical and motivational state, and a self-assessment questionnaire for sleep and awakening quality. Fifteen sport students executed the same protocol sleeping on the same pillow, but without stimulation. Subjective ratings of sleep and awakening quality, sleepiness and motivational state were significantly improved only in the intervention group, but did not impact their perceived physical state. In summary, eight weeks of auditory stimulation with binaural beats improved perceived sleep quality and the post-sleep state of athletes, whereas the effect on physical level is assumed to occur in a time-delayed fashion. It seems to be worthwhile - to further elaborate long-time effects and consequences on physical and mental performance.

  7. Delayed Puberty

    DEFF Research Database (Denmark)

    Kolby, Nanna; Busch, Alexander Siegfried; Juul, Anders

    2017-01-01

    . The underlying reasons for the large variation in the age at pubertal onset are not fully established; however, nutritional status and socioeconomic and environmental factors are known to be influencing, and a significant amount of influencing genetic factors have also been identified. The challenges...... optimal in discriminating especially CDGP from HH. Management of the delayed puberty depends on the etiology. For boys with CDGP an observational period will often reveal imminent puberty. If puberty is not progressing spontaneously, sex steroid replacement is effective in stimulating the development...

  8. Effects of early versus delayed initiation of antiretroviral treatment on clinical outcomes of HIV-1 infection: results from the phase 3 HPTN 052 randomised controlled trial

    Science.gov (United States)

    Grinsztejn, Beatriz; Hosseinipour, Mina C; Ribaudo, Heather J; Swindells, Susan; Eron, Joseph; Chen, Ying Q; Wang, Lei; Ou, San-San; Anderson, Maija; McCauley, Marybeth; Gamble, Theresa; Kumarasamy, Nagalingeshwaran; Hakim, James G; Kumwenda, Johnstone; Pilotto, Jose H S; Godbole, Sheela V; Chariyalertsak, Suwat; de Melo, Marineide Gonçalves; Mayer, Kenneth H; Eshleman, Susan H; Piwowar-Manning, Estelle; Makhema, Joseph; Mills, Lisa A; Panchia, Ravindre; Sanne, Ian; Gallant, Joel; Hoffman, Irving; Taha, Taha E; Nielsen-Saines, Karin; Celentano, David; Essex, Max; Havlir, Diane; Cohen, Myron S

    2014-01-01

    Summary Background Use of antiretroviral treatment for HIV-1 infection has decreased AIDS-related morbidity and mortality and prevents sexual transmission of HIV-1. However, the best time to initiate antiretroviral treatment to reduce progression of HIV-1 infection or non-AIDS clinical events is unknown. We reported previously that early antiretroviral treatment reduced HIV-1 transmission by 96%. We aimed to compare the effects of early and delayed initiation of antiretroviral treatment on clinical outcomes. Methods The HPTN 052 trial is a randomised controlled trial done at 13 sites in nine countries. We enrolled HIV-1-serodiscordant couples to the study and randomly allocated them to either early or delayed antiretroviral treatment by use of permuted block randomisation, stratified by site. Random assignment was unblinded. The HIV-1-infected member of every couple initiated antiretroviral treatment either on entry into the study (early treatment group) or after a decline in CD4 count or with onset of an AIDS-related illness (delayed treatment group). Primary events were AIDS clinical events (WHO stage 4 HIV-1 disease, tuberculosis, and severe bacterial infections) and the following serious medical conditions unrelated to AIDS: serious cardiovascular or vascular disease, serious liver disease, end-stage renal disease, new-onset diabetes mellitus, and non-AIDS malignant disease. Analysis was by intention-to-treat. This trial is registered with ClinicalTrials.gov, number NCT00074581. Findings 1763 people with HIV-1 infection and a serodiscordant partner were enrolled in the study; 886 were assigned early antiretroviral treatment and 877 to the delayed treatment group (two individuals were excluded from this group after randomisation). Median CD4 counts at randomisation were 442 (IQR 373–522) cells per μL in patients assigned to the early treatment group and 428 (357–522) cells per μL in those allocated delayed antiretroviral treatment. In the delayed group

  9. Sleep phenotypes in infants and toddlers with neurogenetic syndromes.

    Science.gov (United States)

    Abel, Emily A; Tonnsen, Bridgette L

    2017-10-01

    Although sleep problems are well characterized in preschool- and school-age children with neurogenetic syndromes, little is known regarding the early emergence of these problems in infancy and toddlerhood. To inform syndrome-specific profiles and targets for intervention, we compared parent-reported sleep problems in infants and toddlers with Angelman syndrome (AS), Williams syndrome (WS), and Prader-Willi syndrome (PWS) with patterns observed among same-aged typically developing (TD) controls. Mothers of 80 children (18 AS, 19 WS, 19 PWS, and 24 TD) completed the Brief Infant Sleep Questionnaire. Primary dependent variables included (1) sleep onset latency, (2) total sleep duration, (3) daytime and nighttime sleep duration, and (4) sleep problem severity, as measured by both maternal impression and National Sleep Foundation guidelines. Sleep problems are relatively common in children with neurogenetic syndromes, with 41% of mothers reporting problematic sleep and 29% of children exhibiting abnormal sleep durations as per national guidelines. Across genetic subgroups, problems are most severe in children with AS and WS, particularly in relation to nighttime sleep duration. Although atypical sleep is characteristically reported in each syndrome later in development, infants and toddlers with PWS exhibited largely typical patterns, potentially indicating delayed onset of sleep problems in concordance with other medical features of PWS. Our findings suggest that sleep problems in neurogenetic syndromes emerge as early as infancy and toddlerhood, with variable profiles across genetic subgroups. This work underscores the importance of early sleep screenings as part of routine medical care of neurosyndromic populations and the need for targeted, syndrome-sensitive treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness.

    Science.gov (United States)

    Chang, Anne-Marie; Aeschbach, Daniel; Duffy, Jeanne F; Czeisler, Charles A

    2015-01-27

    In the past 50 y, there has been a decline in average sleep duration and quality, with adverse consequences on general health. A representative survey of 1,508 American adults recently revealed that 90% of Americans used some type of electronics at least a few nights per week within 1 h before bedtime. Mounting evidence from countries around the world shows the negative impact of such technology use on sleep. This negative impact on sleep may be due to the short-wavelength-enriched light emitted by these electronic devices, given that artificial-light exposure has been shown experimentally to produce alerting effects, suppress melatonin, and phase-shift the biological clock. A few reports have shown that these devices suppress melatonin levels, but little is known about the effects on circadian phase or the following sleep episode, exposing a substantial gap in our knowledge of how this increasingly popular technology affects sleep. Here we compare the biological effects of reading an electronic book on a light-emitting device (LE-eBook) with reading a printed book in the hours before bedtime. Participants reading an LE-eBook took longer to fall asleep and had reduced evening sleepiness, reduced melatonin secretion, later timing of their circadian clock, and reduced next-morning alertness than when reading a printed book. These results demonstrate that evening exposure to an LE-eBook phase-delays the circadian clock, acutely suppresses melatonin, and has important implications for understanding the impact of such technologies on sleep, performance, health, and safety.

  11. Ambulatory assessment of human circadian phase and related sleep disorders from heart rate variability and other non-invasive physiological measurements

    NARCIS (Netherlands)

    Gil Ponce, Enrique

    2017-01-01

    The circadian system plays a key role in our well-being and its effects can be seen in many aspects of our lives. Our master circadian clock, located deep in our brain, influences various physiological processes such as heart rate, body temperature, energy metabolism, hormones, and sleep, to name a

  12. Predictors of poor sleep quality among Lebanese university students: association between evening typology, lifestyle behaviors, and sleep habits.

    Science.gov (United States)

    Kabrita, Colette S; Hajjar-Muça, Theresa A; Duffy, Jeanne F

    2014-01-01

    Adequate, good night sleep is fundamental to well-being and is known to be influenced by myriad biological and environmental factors. Given the unavailability of sleep data about Lebanon, the cultural shifts and socioeconomic pressures that have affected many aspects of society, particularly for students and working adults, as well as our understanding of sleep in university students in other countries, we conducted a national study to assess sleep quality and factors contributing to sleep and general health in a culture-specific context. A self-filled questionnaire, inquiring about sociodemographics, health-risk behaviors, personal health, and evaluating sleep quality and chronotype using standard scales was completed by 540 students at private and public universities in Lebanon. Overall, they reported sleeping 7.95±1.34 hours per night, although 12.3% reported sleeping Sleep Quality Index (PSQI). Sleep timing differed markedly between weekdays and weekends, with bedtimes and wake-up times delayed by 1.51 and 2.43 hours, respectively, on weekends. While most scored in the "neither type" category on the Morningness-Eveningness Questionnaire (MEQ), 24.5% were evening types and 7.3% were morning types. MEQ score was significantly correlated with smoking behavior and daily study onset, as well as with PSQI score, with eveningness associated with greater number of cigarettes, later study times, and poor sleep. We conclude that the prevalence of poor sleep quality among Lebanese university students is associated with reduced sleep duration and shifts in sleep timing between weekdays and weekends, especially among evening types. While chronotype and certain behavioral choices interact to affect sleep dimensions and quality, raising awareness about the importance of obtaining adequate nighttime sleep on daily performance and avoiding risky behaviors may help Lebanese students make better choices in school and work schedules.

  13. Increased commuting to school time reduces sleep duration in adolescents.

    Science.gov (United States)

    Pereira, Erico Felden; Moreno, Claudia; Louzada, Fernando Mazzilli

    2014-02-01

    Active travel to school has been referred to as one way of increasing the level of daily physical exercise, but the actual impacts on student's general health are not clear. Recently, a possible association between active travel to school and the duration of sleep was suggested. Thus, the aim was of this study to investigate the associations between the type of transportation and travel time to school, the time in bed and sleepiness in the classroom of high school students. Information on sleeping habits and travel to school of 1126 high school students were analyzed, where 55.1% were girls with an average age of 16.24 (1.39) years old, in Santa Maria Municipality, Rio Grande do Sul, Brazil. Multiple linear regression and adjusted prevalence rates analyses were carried out. The frequency of active travel found was 61.8%. Associations between time in bed, sleepiness in the classroom and the type of transportation (active or passive) were not identified. Nevertheless, the time in bed was inversely associated with the travel time (p = 0.036) and with a phase delay. In the adjusted analysis, active travel was more incident for the students of schools in the suburbs (PR: 1.68; CI: 1.40-2.01) in comparison with the students of schools in the center. Therefore, longer trips were associated with a reduction of sleep duration of morning and night groups. Interventions concerning active travel to school must be carried out cautiously in order not to cause a reduction of the sleeping time.

  14. Acquired auditory agnosia in childhood and normal sleep electroencephalography subsequently diagnosed as Landau-Kleffner syndrome: a report of three cases.

    Science.gov (United States)

    van Bogaert, Patrick; King, Mary D; Paquier, Philippe; Wetzburger, Catherine; Labasse, Catherine; Dubru, Jean-Marie; Deonna, Thierry

    2013-06-01

      We report three cases of Landau-Kleffner syndrome (LKS) in children (two females, one male) in whom diagnosis was delayed because the sleep electroencephalography (EEG) was initially normal.   Case histories including EEG, positron emission tomography findings, and long-term outcome were reviewed.   Auditory agnosia occurred between the age of 2 years and 3 years 6 months, after a period of normal language development. Initial awake and sleep EEG, recorded weeks to months after the onset of language regression, during a nap period in two cases and during a full night of sleep in the third case, was normal. Repeat EEG between 2 months and 2 years later showed epileptiform discharges during wakefulness and strongly activated by sleep, with a pattern of continuous spike-waves during slow-wave sleep in two patients. Patients were diagnosed with LKS and treated with various antiepileptic regimens, including corticosteroids. One patient in whom EEG became normal on hydrocortisone is making significant recovery. The other two patients did not exhibit a sustained response to treatment and remained severely impaired.   Sleep EEG may be normal in the early phase of acquired auditory agnosia. EEG should be repeated frequently in individuals in whom a firm clinical diagnosis is made to facilitate early treatment. © The Authors. Developmental Medicine & Child Neurology © 2012 Mac Keith Press.

  15. Sleep and Newborns

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Sleep and Newborns KidsHealth / For Parents / Sleep and Newborns ... night it is. How Long Will My Newborn Sleep? Newborns should get 14 to 17 hours of ...

  16. Sleep Apnea Information Page

    Science.gov (United States)

    ... Page You are here Home » Disorders » All Disorders Sleep Apnea Information Page Sleep Apnea Information Page What research is being done? ... Institutes of Health (NIH) conduct research related to sleep apnea in laboratories at the NIH, and also ...

  17. Side Effects: Sleep Problems

    Science.gov (United States)

    Sleep problems are a common side effect during cancer treatment. Learn how a polysomnogram can assess sleep problems. Learn about the benefits of managing sleep disorders in men and women with cancer.

  18. Sleep Eduction: Treatment & Therapy

    Science.gov (United States)

    Find a Sleep Center Use the following fields to locate sleep centers in your area. Search radius (in miles): 10 25 50 Share: Essentials in Sleep Insomnia Overview & Facts Symptoms & Causes Diagnosis & Self Tests ...

  19. Sleep Disorders (PDQ)

    Science.gov (United States)

    ... Types of Cancer Treatment Surgery Radiation Therapy External Beam Radiation Internal Radiation Therapy Side Effects Chemotherapy Immunotherapy ... asleep, sleeping, or waking from sleep, such as walking, talking, or eating. Sleep disorders keep you from ...

  20. Brain Basics: Understanding Sleep

    Science.gov (United States)

    ... You are here Home » Disorders » Patient & Caregiver Education Brain Basics: Understanding Sleep Anatomy of Sleep Sleep Stages ... t form or maintain the pathways in your brain that let you learn and create new memories, ...

  1. Understanding adolescents' sleep patterns and school performance: a critical appraisal.

    Science.gov (United States)

    Wolfson, Amy R; Carskadon, Mary A

    2003-12-01

    The present paper reviews and critiques studies assessing the relation between sleep patterns, sleep quality, and school performance of adolescents attending middle school, high school, and/or college. The majority of studies relied on self-report, yet the researchers approached the question with different designs and measures. Specifically, studies looked at (1) sleep/wake patterns and usual grades, (2) school start time and phase preference in relation to sleep habits and quality and academic performance, and (3) sleep patterns and classroom performance (e.g., examination grades). The findings strongly indicate that self-reported shortened total sleep time, erratic sleep/wake schedules, late bed and rise times, and poor sleep quality are negatively associated with academic performance for adolescents from middle school through the college years. Limitations of the current published studies are also discussed in detail in this review.

  2. Sleep disorder among medical students: relationship to their academic performance.

    Science.gov (United States)

    Abdulghani, Hamza M; Alrowais, Norah A; Bin-Saad, Norah S; Al-Subaie, Nourah M; Haji, Alhan M A; Alhaqwi, Ali I

    2012-01-01

    Medical students are exposed to a significant level of pressure due to academic demands. Their sleep pattern is characterized by insufficient sleep duration, delayed sleep onset, and occurrence of napping episodes during the day. To examine the prevalence of sleep disorder among medical students and investigate any relationship between sleep disorder and academic performance. This is a cross-sectional self-administered questionnaire-based study. The participants were medical students of the first, second, and third academic years. The Epworth Sleepiness Scale (ESS) was also included to identify sleep disorder and grade point average was recorded for academic performance. There were 491 responses with a response rate of 55%. The ESS score demonstrated that 36.6% of participants were considered to have abnormal sleep habits, with a statistically significant increase in female students (p = 0.000). Sleeping between 6-10 h per day was associated with normal ESS scores (p = 0.019) as well as the academic grades ≥ 3.75. Abnormal ESS scores were associated with lower academic achievement (p = 0.002). A high prevalence of sleep disorder was found in this group of students, specifically female students. Analysis of the relationship between sleep disorder and academic performance indicates a significant relationship between abnormal ESS scores, total sleeping hours, and academic performance.

  3. Alcohol consumption, sleep, and academic performance among college students.

    Science.gov (United States)

    Singleton, Royce A; Wolfson, Amy R

    2009-05-01

    Three independent lines of inquiry have found associations between alcohol use and academic performance, sleep and academic performance, and alcohol use and sleep. The present study bridges this research by examining the links among alcohol use, sleep, and academic performance in college students. Personal interview surveys were conducted with a random sample of 236 students (124 women) at a liberal arts college. The interviews measured alcohol consumption, gender, academic class, weekday and weekend bedtimes and rise times, and daytime sleepiness; 95% of the sample granted permission to obtain grade-point average (GPA) and Scholastic Aptitude Test (SAT) scores from official college records. Ordinary least squares regressions showed that alcohol consumption was a significant predictor of four sleep patterns: the duration of sleep, the timing of sleep, the difference between weekday and weekend nighttime sleep hours (oversleep), and the difference between weekday and weekend bedtimes (bedtime delay). Women and students with late sleep schedules were more apt to report daytime sleepiness. SAT score was the strongest predictor of GPA. However, gender, alcohol consumption, sleep duration, and daytime sleepiness also were significant predictors when other variables were controlled. In addition to alcohol's direct relationship with GPA, mediational analysis indicated that alcohol had indirect effects on sleepiness and GPA, primarily through its effect on sleep schedule. The findings show how alcohol use among college students is related to sleep-wake patterns and further support the connection between alcohol use and grades.

  4. Managing sleep and wakefulness in a 24-hour world.

    Science.gov (United States)

    Coveney, Catherine M

    2014-01-01

    This article contributes to literature on the sociology of sleep by exploring the sleeping practices and subjective sleep experiences of two social groups: shift workers and students. It draws on data, collected in the UK from 25 semi-structured interviews, to discuss the complex ways in which working patterns and social activities impact upon experiences and expectations of sleep in our wired awake world. The data show that, typically, sleep is valued and considered to be important for health, general wellbeing, appearance and physical and cognitive functioning. However, sleep time is often cut back on in favour of work demands and social activities. While shift workers described their efforts to fit in an adequate amount of sleep per 24-hour period, for students, the adoption of a flexible sleep routine was thought to be favourable for maintaining a work-social life balance. Collectively, respondents reported using a wide range of strategies, techniques, technologies and practices to encourage, overcome or delay sleep(iness) and boost, promote or enhance wakefulness/alertness at socially desirable times. The analysis demonstrates how social context impacts not only on how we come to think about sleep and understand it, but also how we manage or self-regulate our sleeping patterns. © 2013 The Author. Sociology of Health & Illness © 2013 Foundation for the Sociology of Health & Illness/John Wiley & Sons Ltd.

  5. Topological Acoustic Delay Line

    Science.gov (United States)

    Zhang, Zhiwang; Tian, Ye; Cheng, Ying; Wei, Qi; Liu, Xiaojun; Christensen, Johan

    2018-03-01

    Topological protected wave engineering in artificially structured media is at the frontier of ongoing metamaterials research that is inspired by quantum mechanics. Acoustic analogues of electronic topological insulators have recently led to a wealth of new opportunities in manipulating sound propagation with strikingly unconventional acoustic edge modes immune to backscattering. Earlier fabrications of topological insulators are characterized by an unreconfigurable geometry and a very narrow frequency response, which severely hinders the exploration and design of useful devices. Here we establish topologically protected sound in reconfigurable phononic crystals that can be switched on and off simply by rotating its three-legged "atoms" without altering the lattice structure. In particular, we engineer robust phase delay defects that take advantage of the ultrabroadband reflection-free sound propagation. Such topological delay lines serve as a paradigm in compact acoustic devices, interconnects, and electroacoustic integrated circuits.

  6. Sleeping like a baby: Examining relations between habitual infant sleep, recall memory, and generalization across cues at 10 months.

    Science.gov (United States)

    Lukowski, Angela F; Milojevich, Helen M

    2013-06-01

    Previous research suggests that sleep is related to cognitive functioning in infants and adults. In the present study, we examined whether individual differences in infant sleep habits over the seven days prior to elicited imitation testing were associated with variability in (a) the encoding of 2-step event sequences and (b) memory for the presented information and generalization across cues after a 2-h delay in 10-month-olds. Significant correlations indicated that both daytime napping and nighttime sleep were related to encoding and generalization across cues after the 2-h delay; significant findings were not found in relation to baseline or delayed recall performance. We suggest that individual differences in infant sleep habits may be one mechanism underlying the observed variability in recall memory and generalization as these abilities are coming online late in the first year of life. Published by Elsevier Inc.

  7. Regulation of adolescent sleep: implications for behavior.

    Science.gov (United States)

    Carskadon, Mary A; Acebo, Christine; Jenni, Oskar G

    2004-06-01

    Adolescent development is accompanied by profound changes in the timing and amounts of sleep and wakefulness. Many aspects of these changes result from altered psychosocial and life-style circumstances that accompany adolescence. The maturation of biological processes regulating sleep/wake systems, however, may be strongly related to the sleep timing and amount during adolescence-either as "compelling" or "permissive" factors. The two-process model of sleep regulation posits a fundamental sleep-wake homeostatic process (process S) working in concert with the circadian biological timing system (process C) as the primary intrinsic regulatory factors. How do these systems change during adolescence? We present data from adolescent participants examining EEG markers of sleep homeostasis to evaluate whether process S shows maturational changes permissive of altered sleep patterns across puberty. Our data indicate that certain aspects of the homeostatic system are unchanged from late childhood to young adulthood, while other features change in a manner that is permissive of later bedtimes in older adolescents. We also show alterations of the circadian timing system indicating a possible circadian substrate for later adolescent sleep timing. The circadian parameters we have assessed include phase, period, melatonin secretory pattern, light sensitivity, and phase relationships, all of which show evidence of changes during pubertal development with potential to alter sleep patterns substantially. However the changes are mediated-whether through process S, process C, or by a combination-many adolescents have too little sleep at the wrong circadian phase. This pattern is associated with increased risks for excessive sleepiness, difficulty with mood regulation, impaired academic performance, learning difficulties, school tardiness and absenteeism, and accidents and injuries.

  8. Effects of sleep disruption and high fat intake on glucose metabolism in mice.

    Science.gov (United States)

    Ho, Jacqueline M; Barf, R Paulien; Opp, Mark R

    2016-06-01

    sleep phase contributes to restorative effects of recovery sleep on glycemic control. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Comparision of Parent Reported Sleeping Habits and Sleep Problems Between Attention Deficit and Hyperactivity Disorder and Healthy Controls

    Directory of Open Access Journals (Sweden)

    Yusuf Ozturk

    2017-12-01

    Full Text Available Attention Deficit and Hyperactivity Disorder (ADHD children has been shown to affect the quality of sleep. In this study it is aimed to evaluate sleep habits and sleep problems between the cases who are diagnosed with ADHD and healthy controls. The study group consisted of 61 children (8-12 years old with ADHD; the control group (87 children comprised patients of other clinics at hospital. The Kiddie Schedule for Affective Disorders and Schizophrenia for School Aged Children-Present and Lifetime Version (K-SADS-PL and DuPaul ADHD Rating Scale vere used. Children's sleep habits and sleep problems were assessed with the Children's Sleep Habits Questionnaire. ADHD group compared to healthy controls; statistical significant difference was found in bedtime resistance, the sleep onset delay, the sleep duration, the sleep anxiety, the night wakings, the parasomnias and the daytime sleepiness but statistical significant difference wasn’t found the sleep disordered breathing. In our study, problems in the sleep habits evaluated by parents ADHD are more than campared with healty controls likewise literature. However, further studies with larger sample size and objective measures such as actigraphy and polysomnography may allow us to have more knowledge in this area. [JCBPR 2017; 6(3.000: 108-114

  10. Sleep physiology and sleep disorders in childhood

    Directory of Open Access Journals (Sweden)

    El Shakankiry HM

    2011-09-01

    Full Text Available Hanan M El ShakankiryKing Fahd University Hospital, Al Dammam University, Al Khobar, Kingdom of Saudi ArabiaAbstract: Sleep has long been considered as a passive phenomenon, but it is now clear that it is a period of intense brain activity involving higher cortical functions. Overall, sleep affects every aspect of a child's development, particularly higher cognitive functions. Sleep concerns are ranked as the fifth leading concern of parents. Close to one third of all children suffer from sleep disorders, the prevalence of which is increased in certain pediatric populations, such as children with special needs, children with psychiatric or medical diagnoses and children with autism or pervasive developmental disorders. The paper reviews sleep physiology and the impact, classification, and management of sleep disorders in the pediatric age group.Keywords: sleep physiology, sleep disorders, childhood, epilepsy

  11. Sleep: A Health Imperative

    Science.gov (United States)

    Luyster, Faith S.; Strollo, Patrick J.; Zee, Phyllis C.; Walsh, James K.

    2012-01-01

    Chronic sleep deficiency, defined as a state of inadequate or mistimed sleep, is a growing and underappreciated determinant of health status. Sleep deprivation contributes to a number of molecular, immune, and neural changes that play a role in disease development, independent of primary sleep disorders. These changes in biological processes in response to chronic sleep deficiency may serve as etiological factors for the development and exacerbation of cardiovascular and metabolic diseases and, ultimately, a shortened lifespan. Sleep deprivation also results in significant impairments in cognitive and motor performance which increase the risk of motor vehicle crashes and work-related injuries and fatal accidents. The American Academy of Sleep Medicine and the Sleep Research Society have developed this statement to communicate to national health stakeholders the current knowledge which ties sufficient sleep and circadian alignment in adults to health. Citation: Luyster FS; Strollo PJ; Zee PC; Walsh JK. Sleep: a health imperative. SLEEP 2012;35(6):727-734. PMID:22654183

  12. Sleep for cognitive enhancement

    Directory of Open Access Journals (Sweden)

    Susanne eDiekelmann

    2014-04-01

    Full Text Available Sleep is essential for effective cognitive functioning. Loosing even a few hours of sleep can have detrimental effects on a wide variety of cognitive processes such as attention, language, reasoning, decision making, learning and memory. While sleep is necessary to ensure normal healthy cognitive functioning, it can also enhance performance beyond the boundaries of the normal condition. This article discusses the enhancing potential of sleep, mainly focusing on the domain of learning and memory. Sleep is known to facilitate the consolidation of memories learned before sleep as well as the acquisition of new memories to be learned after sleep. According to a widely held model this beneficial effect of sleep relies on the neuronal reactivation of memories during sleep that is associated with sleep-specific brain oscillations (slow oscillations, spindles, ripples as well as a characteristic neurotransmitter milieu. Recent research indicates that memory processing during sleep can be boosted by (i cueing memory reactivation during sleep, (ii stimulating sleep-specific brain oscillations, and (iii targeting specific neurotransmitter systems pharmacologically. Olfactory and auditory cues can be used, for example, to increase reactivation of associated memories during post-learning sleep. Intensifying neocortical slow oscillations (the hallmark of slow wave sleep by electrical or auditory stimulation and modulating specific neurotransmitters such as noradrenaline and glutamate likewise facilitates memory processing during sleep. With this evidence in mind, this article concludes by discussing different methodological caveats and ethical issues that should be considered when thinking about using sleep for cognitive enhancement in everyday applications.

  13. Sleep and academic performance in later adolescence: results from a large population-based study.

    Science.gov (United States)

    Hysing, Mari; Harvey, Allison G; Linton, Steven J; Askeland, Kristin G; Sivertsen, Børge

    2016-06-01

    The aim of the current study was to assess the association between sleep duration and sleep patterns and academic performance in 16-19 year-old adolescents using registry-based academic grades. A large population-based study from Norway conducted in 2012, the youth@hordaland-survey, surveyed 7798 adolescents aged 16-19 years (53.5% girls). The survey was linked with objective outcome data on school performance. Self-reported sleep measures provided information on sleep duration, sleep efficiency, sleep deficit and bedtime differences between weekday and weekend. School performance [grade point average (GPA)] was obtained from official administrative registries. Most sleep parameters were associated with increased risk for poor school performance. After adjusting for sociodemographic information, short sleep duration and sleep deficit were the sleep measures with the highest odds of poor GPA (lowest quartile). Weekday bedtime was associated significantly with GPA, with adolescents going to bed between 22:00 and 23:00 hours having the best GPA. Also, delayed sleep schedule during weekends was associated with poor academic performance. The associations were somewhat reduced after additional adjustment for non-attendance at school, but remained significant in the fully adjusted models. In conclusion, the demonstrated relationship between sleep problems and poor academic performance suggests that careful assessment of sleep is warranted when adolescents are underperforming at school. Future studies are needed on the association between impaired sleep in adolescence and later functioning in adulthood. © 2016 European Sleep Research Society.

  14. Adolescents' Sleep Behaviors and Perceptions of Sleep

    Science.gov (United States)

    Noland, Heather; Price, James H.; Dake, Joseph; Telljohann, Susan K.

    2009-01-01

    Background: Sleep duration affects the health of children and adolescents. Shorter sleep durations have been associated with poorer academic performance, unintentional injuries, and obesity in adolescents. This study extends our understanding of how adolescents perceive and deal with their sleep issues. Methods: General education classes were…

  15. No Compromise of Competition Sleep Compared With Habitual Sleep in Elite Australian Footballers.

    Science.gov (United States)

    Lalor, Benita J; Halson, Shona L; Tran, Jacqueline; Kemp, Justin G; Cormack, Stuart J

    2018-01-01

    To assess the impact of match-start time and days relative to match compared with the habitual sleep characteristics of elite Australian Football (AF) players. 45 elite male AF players were assessed during the preseason (habitual) and across 4 home matches during the season. Players wore an activity monitor the night before (-1), night of (0), 1 night after (+1), and 2 nights (+2) after each match and completed a self-reported rating of sleep quality. A 2-way ANOVA with Tukey post hoc was used to determine differences in sleep characteristics between match-start times and days relative to the match. Two-way nested ANOVA was conducted to examine differences between competition and habitual phases. Effect size ± 90% confidence interval (ES ± 90% CI) was calculated to quantify the magnitude of pairwise differences. Differences observed in sleep-onset latency (ES = 0.11 ± 0.16), sleep rating (ES = 0.08 ± 0.14), and sleep duration (ES = 0.08 ± 0.01) between competition and habitual periods were trivial. Sleep efficiency was almost certainly higher during competition than habitual, but this was not reflected in the subjective rating of sleep quality. Elite AF competition does not cause substantial disruption to sleep characteristics compared with habitual sleep. While match-start time has some impact on sleep variables, it appears that the match itself is more of a disruption than the start time. Subjective ratings of sleep from well-being questionnaires appear limited in their ability to accurately provide an indication of sleep quality.

  16. Effects of cocaine, methamphetamine and modafinil challenge on sleep rebound after paradoxical sleep deprivation in rats

    Directory of Open Access Journals (Sweden)

    R.C.S Martins

    2008-01-01

    Full Text Available Sleep loss is both common and critically relevant to our society and might lead to the abuse of psychostimulants such as amphetamines, cocaine and modafinil. Since psychoactive substance abuse often occurs within a scenario of sleep deficit, the purpose of this investigation was to compare the sleep patterns of rats challenged with cocaine (7 mg/kg, ip, methamphetamine (7 mg/kg, ip, or modafinil (100 mg/kg, ip subsequent to paradoxical sleep deprivation (PSD for 96 h. Our results show that, immediately after 96 h of PSD, rats (10 per group that were injected with a psychostimulant presented lower percentages of paradoxical sleep compared to those injected with saline (P < 0.01. Regarding slow wave sleep (SWS, rats injected with psychostimulants after PSD presented a late rebound (on the second night subsequent to the injection in the percentage of this phase of sleep when compared to PSD rats injected with saline (P < 0.05. In addition, the current study has produced evidence of the characteristic effect of each drug on sleep architecture. Home cage control rats injected with modafinil and methamphetamine showed a reduction in SWS compared with the saline group. Methamphetamine affected sleep patterns most, since it significantly reduced paradoxical sleep, SWS and sleep efficiency before and after PSD compared to control (P < 0.05. Cocaine was the psychostimulant causing the least changes in sleep pattern in relation to those observed after saline injection. Therefore, our results suggest that abuse of these psychostimulants in a PSD paradigm aggravates their impact on sleep patterns.

  17. Are You Sleep Deprived?

    Science.gov (United States)

    ... of this page please turn JavaScript on. Feature: Sleep Disorders Are You Sleep Deprived? Past Issues / Summer 2015 Table of Contents ... even if you think you've had enough sleep? You might have a sleep disorder. There are ...

  18. The Sleeping Cerebellum

    NARCIS (Netherlands)

    Canto, Cathrin B; Onuki, Yoshiyuki; Bruinsma, Bastiaan; van der Werf, Ysbrand D; De Zeeuw, Chris I

    2017-01-01

    We sleep almost one-third of our lives and sleep plays an important role in critical brain functions like memory formation and consolidation. The role of sleep in cerebellar processing, however, constitutes an enigma in the field of neuroscience; we know little about cerebellar sleep-physiology,

  19. Deficient Sleep in Mouse Models of Fragile X Syndrome

    Directory of Open Access Journals (Sweden)

    R. Michelle Saré

    2017-09-01

    Full Text Available In patients with fragile X syndrome (FXS, sleep problems are commonly observed but are not well characterized. In animal models of FXS (dfmr1 and Fmr1 knockout (KO/Fxr2 heterozygote circadian rhythmicity is affected, but sleep per se has not been examined. We used a home-cage monitoring system to assess total sleep time in both light and dark phases in Fmr1 KO mice at different developmental stages. Fmr1 KOs at P21 do not differ from controls, but genotype × phase interactions in both adult (P70 and P180 groups are statistically significant indicating that sleep in Fmr1 KOs is reduced selectively in the light phase compared to controls. Our results show the emergence of abnormal sleep in Fmr1 KOs during the later stages of brain maturation. Treatment of adult Fmr1 KO mice with a GABAB agonist, R-baclofen, did not restore sleep duration in the light phase. In adult (P70 Fmr1 KO/Fxr2 heterozygote animals, total sleep time was further reduced, once again in the light phase. Our data highlight the importance of the fragile X genes (Fmr1 and Fxr2 in sleep physiology and confirm the utility of these mouse models in enhancing our understanding of sleep disorders in FXS.

  20. Household chaos and family sleep during infants' first year.

    Science.gov (United States)

    Whitesell, Corey J; Crosby, Brian; Anders, Thomas F; Teti, Douglas M

    2018-05-21

    Household chaos has been linked with dysregulated family and individual processes. The present study investigated linkages between household chaos and infant and parent sleep, a self-regulated process impacted by individual, social, and environmental factors. Studies of relations between household chaos and child sleep have focused on older children and teenagers, with little attention given to infants or parent sleep. This study examines these relationships using objective measures of household chaos and sleep while controlling for, respectively, maternal emotional availability at bedtime and martial adjustment, in infant and parent sleep. Multilevel modeling examined mean and variability of sleep duration and fragmentation for infants, mothers, and fathers when infants were 1, 3, 6, 9, and 12 months (N = 167). Results indicated infants in higher chaos homes experienced delays in sleep consolidation patterns, with longer and more variable sleep duration, and greater fragmentation. Parent sleep was also associated with household chaos such that in higher chaos homes, mothers and fathers experienced greater variability in sleep duration, which paralleled infant findings. In lower chaos homes, parents' sleep fragmentation mirrored infants' decreasingly fragmented sleep across the first year and remained lower at all timepoints compared to parents and infants in high chaos homes. Collectively, these findings indicate that after controlling for maternal emotional availability and marital adjustment (respectively) household chaos has a dysregulatory impact on infant and parent sleep. Results are discussed in terms of the potential for chaos-induced poor sleep to dysregulate daytime functioning and, in turn, place parent-infant relationships at risk. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  1. Design and development of a surface micro-machined push–pull-type true-time-delay phase shifter on an alumina substrate for Ka-band T/R module application

    International Nuclear Information System (INIS)

    Dey, Sukomal; Koul, Shiban K

    2012-01-01

    A radio frequency micro-electro-mechanical system (RF-MEMS) phase shifter based on the distributed MEMS transmission line (DMTL) concept towards maximum achievable phase shift with low actuation voltage with good figure of merit (FOM) is presented in this paper. This surface micro-machined analog DMTL phase shifter demonstrates low power consumption for implementation in a Ka-band transmit/receive (T/R) module. The push–pull-type switch has been designed and optimized with an analytical method and validated with simulation, which is the fundamental building block of the design of a true-time-delay phase shifter. Change in phase has been designed and optimized in push and pull states with reference to the up-state performance of the phase shifter. The working principle of this push–pull-type DMTL phase shifter has been comprehensively worked out. A thorough detail of the design and performance analysis of the phase shifter has been carried out with various structural parameters using commercially available simulation tools with reference to a change in phase shift and has been verified using a system level simulation. The phase shifter is fabricated on the alumina substrate, using a suspended gold bridge membrane with a surface micromachining process. Asymmetric behaviour of push–pull bridge configuration has been noted and a corresponding effect on mechanical, electrical and RF performances has been extensively investigated. It is demonstrated 114° dB −1 FOM over 0–40 GHz band, which is the highest achievable FOM from a unit cell on an alumina substrate reported so far. A complete phase shifter contributes to a continuous differential phase shift of 0°–360° over 0–40 GHz band with a minimum actuation voltage of 8.1 V which is the highest achievable phase shift with the lowest actuation voltage as per till date on the alumina substrate with good repeatability and return loss better than 11.5 dB over 0–40 GHz band. (paper)

  2. Effects of sleep deprivation with reference to military operations.

    Science.gov (United States)

    Giam, G C

    1997-01-01

    . Sleep lost need not be replaced hour-for-hour. Therefore, after operations, personnel need continuous sleep for only 10 to 12 hours as longer sleep increases sleep inertia and delays getting back to normal schedules.

  3. [Natural factors influencing sleep].

    Science.gov (United States)

    Jurkowski, Marek K; Bobek-Billewicz, Barbara

    2007-01-01

    Sleep is a universal phenomenon of human and animal lives, although the importance of sleep for homeo-stasis is still unknown. Sleep disturbances influence many behavioral and physiologic processes, leading to health complications including death. On the other hand, sleep improvement can beneficially influence the course of healing of many disorders and can be a prognostic of health recovery. The factors influencing sleep have different biological and chemical origins. They are classical hormones, hypothalamic releasing and inhibitory hormones, neuropeptides, peptides and others as cytokines, prostaglandins, oleamid, adenosine, nitric oxide. These factors regulate most physiologic processes and are likely elements integrating sleep with physiology and physiology with sleep in health and disorders.

  4. Sleep in healthy black and white adolescents.

    Science.gov (United States)

    Matthews, Karen A; Hall, Martica; Dahl, Ronald E

    2014-05-01

    Inadequate sleep among adolescents has negative consequences for self-regulation, emotional well-being, and risk behaviors. Using multiple assessment methods, we evaluated the adequacy of sleep among healthy adolescents from a lower socioeconomic community and expected differences by race. A total of 250 healthy high school students enrolled in public school (mean age: 15.7 years; 57% black, 54% female) from families of low to middle class according to the Hollingshead scale participated in weeklong assessments of sleep duration and fragmentation, assessed by using actigraphy; sleep duration and perceived quality, assessed by using daily diaries; and daytime sleepiness and sleep delay, assessed by using a questionnaire. Students slept during the school week a mean ± SD of 6.0 ± 0.9 hours per night according to actigraphy and 6.8 ± 1.1 hours according to daily diary, and during the weekend, a mean of 7.4 ± 1.2 and 8.7 ± 1.4 hours, respectively. Black participants and male participants slept less and had more fragmented sleep; female participants reported poorer quality of sleep in their daily diaries and more daytime sleepiness. The results remained significant after adjustments for age, physical activity, smoking status, and percentile BMI. Most students slept less than the 8 to 9 hours suggested by the guidelines of the Centers for Disease Control and Prevention. Black male participants had the least amount of sleep, which may play a role in the substantial risks experienced by this demographic group. Our findings are consistent with recommendations that pediatricians should routinely screen their adolescent patients about their sleep, especially those from at-risk subgroups. Copyright © 2014 by the American Academy of Pediatrics.

  5. Sleep and cognition.

    Science.gov (United States)

    Deak, Maryann C; Stickgold, Robert

    2010-07-01

    Sleep is a complex physiologic state, the importance of which has long been recognized. Lack of sleep is detrimental to humans and animals. Over the past decade, an important link between sleep and cognitive processing has been established. Sleep plays an important role in consolidation of different types of memory and contributes to insightful, inferential thinking. While the mechanism by which memories are processed in sleep remains unknown, several experimental models have been proposed. This article explores the link between sleep and cognition by reviewing (1) the effects of sleep deprivation on cognition, (2) the influence of sleep on consolidation of declarative and non-declarative memory, and (3) some proposed models of how sleep facilitates memory consolidation in sleep. Copyright © 2010 John Wiley & Sons, Ltd. For further resources related to this article, please visit the WIREs website. Copyright © 2010 John Wiley & Sons, Ltd.

  6. Ramadan fasting, mental health and sleep-wake pattern

    Directory of Open Access Journals (Sweden)

    Mohsen Khoshniat Nikoo

    2012-06-01

    Full Text Available Background: Life style Changes during Ramadan month could possibly affect sleep-related behaviors such as total daily sleep time, sleep and wake up time and brain waves. In addition, Spirituality and religiosity have a marvelous influence on mental health and effective solutions against stress are being religious and believe in God. This review discusses the results of all related studies about possible effects of Ramadan fasting on various aspects of sleep pattern and mental health. Methods: Keywords such as ‘Ramadan’, ‘Ramadan Fasting’, ‘Islamic Fasting’, ‘Fasting in Ramadan’ and Fasting along Sleep, Chronotype, Sleep Latency, REM, NREM, Brain Wave, Psychology, Mental health, Religion, Mood, Depression, Social interaction, Depressive illness, Psychomotor performances, Bipolar disorders, Accident, Mania, Anxiety and Stress were searched via PubMed database, Scientific Information Datebas (SID and also some local journals, hence, 103 related articles from 1972 until 2010 were studied. Results: The results of studies about the effects of Ramadan fasting on sleep pattern is not similar and these differences could be due to cultural and life style discrepancy in several countries. Fasting during Ramadan could lead to delay in sleep-wake cycle, decrease in deep sleep and lack of awareness during the day. Conclusion: There are various reasons such as dietary pattern, hormonal changes and also stress which could alter the quantity and quality of sleep during Ramadan. Also, according to the available information, there is a relationship between fasting and mental health.

  7. Bright-light exposure during daytime sleeping affects nocturnal melatonin secretion after simulated night work.

    Science.gov (United States)

    Nagashima, Shunsuke; Osawa, Madoka; Matsuyama, Hiroto; Ohoka, Wataru; Ahn, Aemi; Wakamura, Tomoko

    2018-02-01

    significant differences were found in any sleep parameter. Our study demonstrated that daytime sleeping under bright-light conditions after night work could not reduce late evening melatonin secretion until midnight or delay the phase of melatonin secretion without decreasing the quality of the daytime sleeping. Thus, these results suggested that, to enhance melatonin secretion and to maintain their conventional sleep-wake cycle, after night work, shift workers should sleep during the daytime under bright-light conditions rather than dim-light conditions.

  8. The Impact of Sleep Deprivation on the Brain

    Science.gov (United States)

    Trošt Bobić, Tatjana; Šečić, Ana; Zavoreo, Iris; Matijević, Valentina; Filipović, Branimir; Kolak, Željka; Bašić Kes, Vanja; Ciliga, Dubravka; Sajković, Dubravka

    2016-09-01

    Each sleep phase is characterized by specific chemical, cellular and anatomic events of vital importance for normal neural functioning. Different forms of sleep deprivation may lead to a decline of cognitive functions in individuals. Studies in this field make a distinction between total sleep deprivation, chronic sleep restriction, and the situation of sleep disruption. Investigations covering the acute effects of sleep deprivation on the brain show that the discovered behavioral deficits in most cases regenerate after two nights of complete sleep. However, some studies done on mice emphasize the possible chronic effects of long-term sleep deprivation or chronic restriction on the occurrence of neurodegenerative diseases such as Alzheimer’s disease and dementia. In order to better understand the acute and chronic effects of sleep loss, the mechanisms of neural adaptation in the situations of insufficient sleep need to be further investigated. Future integrative research on the impact of sleep deprivation on neural functioning measured through the macro level of cognitive functions and the micro molecular and cell level could contribute to more accurate conclusions about the basic cellular mechanisms responsible for the detected behavioral deficits occurring due to sleep deprivation.

  9. Sleep disorders, depression, anxiety and satisfaction with life among young adults: a survey of university students in Auckland, New Zealand.

    Science.gov (United States)

    Samaranayake, Chinthaka B; Arroll, Bruce; Fernando, Antonio T

    2014-08-01

    Sleep symptoms, depression and anxiety often coexist and tertiary students are a population group that are increasingly recognised to be at risk. However the rates of these conditions in the New Zealand population are poorly understood. The aim of this study was to determine the rates of sleep disorders, depression and anxiety, and identify correlations between satisfactions with life among university students in Auckland. Auckland Sleep Questionnaire (ASQ) was administered to undergraduate students from six schools of The University of Auckland. The different types of sleep disorders were calculated for the students who reported a significant sleep problem lasting more than 1 month. The rate of depression, anxiety and substance use as well as the satisfaction with life scale scores were also calculated for the whole cohort. A total of 1933 students were invited to participate and 66.8% completed the questionnaire. The median age was 20 years (range 16-38) and women represented 63.9% of the total group. A total of 39.4% of the students surveyed reported having significant sleep symptoms lasting longer than 1 month. The most prevalent causes for sleep symptoms were depression and anxiety. Delayed sleep phase disorder was found in 24.9% of students and parasomnias were reported by 12.4%. Depression and anxiety were present in 17.3% and 19.7% of the total group respectively, and 7.3% of students had thoughts of "being better off dead" or self-harm. A total of 15.5% students were found to have a CAGE score greater than or equal to 2 and 9.3% reported using recreational drugs in the last 3 months. Moderate negative correlations between SWLS scores and depression and anxiety were found (r=-0.45 and r=-0.37 respectively). A large number of university students are suffering from significant sleep symptoms. Mood disorders, substance use, and circadian rhythm disorders can greatly contribute to sleep difficulties in this population group. The study also showed that harmful

  10. Sleep disorders in children

    OpenAIRE

    Montgomery, Paul; Dunne, Danielle

    2007-01-01

    Sleep disorders may affect 20-30% of young children, and include excessive daytime sleepiness, problems getting to sleep (dysomnias), or undesirable phenomena during sleep (parasomnias), such as sleep terrors, and sleepwalking. Children with physical or learning disabilities are at increased risk of sleep disorders. Other risk factors include the child being the first born, having a difficult temperament or having had colic, and increased maternal responsiveness.

  11. Sleep disorders in children

    OpenAIRE

    Bruni, Oliveiero; Novelli, Luana

    2010-01-01

    Sleep disorders may affect between 20% and 30% of young children, and include problems getting to sleep (dyssomnias) or undesirable phenomena during sleep (parasomnias), such as sleep terrors and sleepwalking. Children with physical or learning disabilities are at increased risk of sleep disorders. Other risk factors include the child being the first born, having a difficult temperament or having had colic, and increased maternal responsiveness.

  12. Ostriches sleep like platypuses.

    Directory of Open Access Journals (Sweden)

    John A Lesku

    Full Text Available Mammals and birds engage in two distinct states of sleep, slow wave sleep (SWS and rapid eye movement (REM sleep. SWS is characterized by slow, high amplitude brain waves, while REM sleep is characterized by fast, low amplitude waves, known as activation, occurring with rapid eye movements and reduced muscle tone. However, monotremes (platypuses and echidnas, the most basal (or 'ancient' group of living mammals, show only a single sleep state that combines elements of SWS and REM sleep, suggesting that these states became temporally segregated in the common ancestor to marsupial and eutherian mammals. Whether sleep in basal birds resembles that of monotremes or other mammals and birds is unknown. Here, we provide the first description of brain activity during sleep in ostriches (Struthio camelus, a member of the most basal group of living birds. We found that the brain activity of sleeping ostriches is unique. Episodes of REM sleep were delineated by rapid eye movements, reduced muscle tone, and head movements, similar to those observed in other birds and mammals engaged in REM sleep; however, during REM sleep in ostriches, forebrain activity would flip between REM sleep-like activation and SWS-like slow waves, the latter reminiscent of sleep in the platypus. Moreover, the amount of REM sleep in ostriches is greater than in any other bird, just as in platypuses, which have more REM sleep than other mammals. These findings reveal a recurring sequence of steps in the evolution of sleep in which SWS and REM sleep arose from a single heterogeneous state that became temporally segregated into two distinct states. This common trajectory suggests that forebrain activation during REM sleep is an evolutionarily new feature, presumably involved in performing new sleep functions not found in more basal animals.

  13. School-Based Sleep Education Programs for Short Sleep Duration in Adolescents: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Chung, Ka-Fai; Chan, Man-Sum; Lam, Ying-Yin; Lai, Cindy Sin-Yee; Yeung, Wing-Fai

    2017-06-01

    Insufficient sleep among students is a major school health problem. School-based sleep education programs tailored to reach large number of students may be one of the solutions. A systematic review and meta-analysis was conducted to summarize the programs' effectiveness and current status. Electronic databases were searched up until May 2015. Randomized controlled trials of school-based sleep intervention among 10- to 19-year-old students with outcome on total sleep duration were included. Methodological quality of the studies was assessed using the Cochrane's risk of bias assessment. Seven studies were included, involving 1876 students receiving sleep education programs and 2483 attending classes-as-usual. Four weekly 50-minute sleep education classes were most commonly provided. Methodological quality was only moderate, with a high or an uncertain risk of bias in several domains. Compared to classes-as-usual, sleep education programs produced significantly longer weekday and weekend total sleep time and better mood among students at immediate post-treatment, but the improvements were not maintained at follow-up. Limited by the small number of studies and methodological limitations, the preliminary data showed that school-based sleep education programs produced short-term benefits. Future studies should explore integrating sleep education with delayed school start time or other more effective approaches. © 2017, American School Health Association.

  14. Sleep Promotes Lasting Changes in Selective Memory for Emotional Scenes

    Directory of Open Access Journals (Sweden)

    Jessica ePayne

    2012-11-01

    Full Text Available Although we know that emotional events enjoy a privileged status in our memories, we still have much to learn about how emotional memories are processed, stored, and how they change over time. Here we show a positive association between REM sleep and the selective consolidation of central, negative aspects of complex scenes. Moreover, we show that the placement of sleep is critical for this selective emotional memory benefit. When testing occurred 24hr post-encoding, subjects who slept soon after learning (24hr Sleep First group had superior memory for emotional objects compared to subjects whose sleep was delayed for 16hr post-encoding following a full day of wakefulness (24hr Wake First group. However, this increase in memory for emotional objects corresponded with a decrease in memory for the neutral backgrounds on which these objects were placed. Furthermore, memory for emotional objects in the 24hr Sleep First group was comparable to performance after just a 12hr delay containing a night of sleep, suggesting that sleep soon after learning selectively stabilizes emotional memory. These results suggest that the sleeping brain preserves in long-term memory only what is emotionally salient and perhaps most adaptive to remember.

  15. Sleep promotes lasting changes in selective memory for emotional scenes.

    Science.gov (United States)

    Payne, Jessica D; Chambers, Alexis M; Kensinger, Elizabeth A

    2012-01-01

    Although we know that emotional events enjoy a privileged status in our memories, we still have much to learn about how emotional memories are processed, stored, and how they change over time. Here we show a positive association between REM sleep and the selective consolidation of central, negative aspects of complex scenes. Moreover, we show that the placement of sleep is critical for this selective emotional memory benefit. When testing occurred 24 h post-encoding, subjects who slept soon after learning (24 h Sleep First group) had superior memory for emotional objects compared to subjects whose sleep was delayed for 16 h post-encoding following a full day of wakefulness (24 h Wake First group). However, this increase in memory for emotional objects corresponded with a decrease in memory for the neutral backgrounds on which these objects were placed. Furthermore, memory for emotional objects in the 24 h Sleep First group was comparable to performance after just a 12 h delay containing a night of sleep, suggesting that sleep soon after learning selectively stabilizes emotional memory. These results suggest that the sleeping brain preserves in long-term memory only what is emotionally salient and perhaps most adaptive to remember.

  16. Delay 25 an ASIC for timing adjustment in LHC

    NARCIS (Netherlands)

    Furtado, H.; Schrader, J.H.R.; Marchioro, A.; Moreira, P.

    A five channel programmable delay line ASIC was designed featuring 4 channels that allow to phase delay periodic or non-periodic digital signals and a master channel that can be used to phase delay a clock signal. The master channel serves as a calibration reference guaranteeing independence from

  17. Comparative Effectiveness of Three Occupational Therapy Sleep Interventions: A Randomized Controlled Study.

    Science.gov (United States)

    Gutman, Sharon A; Gregory, Kristin A; Sadlier-Brown, Megan M; Schlissel, Marcy A; Schubert, Allison M; Westover, Lee Ann; Miller, Richard C

    2017-01-01

    Although sleep intervention is within the domain of occupational therapy, few studies exist supporting practice. Effectiveness of three sleep interventions was compared: Dreampad Pillow®, iRest® meditation, and sleep hygiene. Twenty-nine participants were randomly assigned to the Dreampad Pillow® ( n = 10), iRest® meditation ( n = 9), and sleep hygiene ( n = 10) groups. In Phase 1, all participants used a 7-day sleep hygiene regimen to reduce poor sleep habits. In Phase 2 (14 days), 10 participants used the Dreampad Pillow® and sleep hygiene, nine used the iRest meditation and sleep hygiene, and 10 continued sleep hygiene only. At intervention-end, the iRest meditation group experienced statistically greater time asleep than both the Dreampad Pillow® ( p meditation ( p occupational therapy's domain.

  18. Can exercise ameliorate treatment toxicity during the initial phase of testosterone deprivation in prostate cancer patients? Is this more effective than delayed rehabilitation?

    Directory of Open Access Journals (Sweden)

    Newton Robert U

    2012-09-01

    Full Text Available Abstract Background There has been substantial increase in use of androgen deprivation therapy as adjuvant management of prostate cancer. However, this leads to a range of musculoskeletal toxicities including reduced bone mass and increased skeletal fractures compounded with rapid metabolic alterations, including increased body fat, reduced lean mass, insulin resistance and negative lipoprotein profile, increased incidence of cardiovascular and metabolic morbidity, greater distress and reduced quality of life. Numerous research studies have demonstrated certain exercise prescriptions to be effective at preventing or even reversing these treatment toxicities. However, all interventions to date have been of rehabilitative intent being implemented after a minimum of 3 months since initiation of androgen deprivation, by which time considerable physical and psychological health problems have manifested. The pressing question is whether it is more efficacious to commence exercise therapy at the same time as initiating androgen deprivation, so treatment induced adverse effects can be immediately attenuated or indeed prevented. Methods/design We are proposing a multi-site randomized controlled trial with partial crossover to examine the effects of timing of exercise implementation (immediate or delayed on preserving long-term skeletal health, reversing short- and long-term metabolic and cardiovascular risk factors, and supporting mental health in men receiving androgen deprivation therapy. 124 men who are about to initiate androgen deprivation for prostate cancer will be randomized to immediate or delayed groups. Immediate will commence a 6-month exercise program within 7–10 days of their first dose. Delayed will receive usual care for 6 months and then commence the exercise program for 6 months (partial cross-over. Immediate will be free to adopt the lifestyle of their choosing following the initial 6-month intervention. Measurements for primary and

  19. Can exercise ameliorate treatment toxicity during the initial phase of testosterone deprivation in prostate cancer patients? Is this more effective than delayed rehabilitation?

    International Nuclear Information System (INIS)

    Newton, Robert U; Taaffe, Dennis R; Spry, Nigel; Cormie, Prue; Chambers, Suzanne K; Gardiner, Robert A; Shum, David HK; Joseph, David; Galvão, Daniel A

    2012-01-01

    There has been substantial increase in use of androgen deprivation therapy as adjuvant management of prostate cancer. However, this leads to a range of musculoskeletal toxicities including reduced bone mass and increased skeletal fractures compounded with rapid metabolic alterations, including increased body fat, reduced lean mass, insulin resistance and negative lipoprotein profile, increased incidence of cardiovascular and metabolic morbidity, greater distress and reduced quality of life. Numerous research studies have demonstrated certain exercise prescriptions to be effective at preventing or even reversing these treatment toxicities. However, all interventions to date have been of rehabilitative intent being implemented after a minimum of 3 months since initiation of androgen deprivation, by which time considerable physical and psychological health problems have manifested. The pressing question is whether it is more efficacious to commence exercise therapy at the same time as initiating androgen deprivation, so treatment induced adverse effects can be immediately attenuated or indeed prevented. We are proposing a multi-site randomized controlled trial with partial crossover to examine the effects of timing of exercise implementation (immediate or delayed) on preserving long-term skeletal health, reversing short- and long-term metabolic and cardiovascular risk factors, and supporting mental health in men receiving androgen deprivation therapy. 124 men who are about to initiate androgen deprivation for prostate cancer will be randomized to immediate or delayed groups. Immediate will commence a 6-month exercise program within 7–10 days of their first dose. Delayed will receive usual care for 6 months and then commence the exercise program for 6 months (partial cross-over). Immediate will be free to adopt the lifestyle of their choosing following the initial 6-month intervention. Measurements for primary and secondary endpoints will take place at baseline, 6

  20. Digital Signal Processing Applications and Implementation for Accelerators Digital Notch Filter with Programmable Delay and Betatron Phase Adjustment for the PS, SPS and LHC Transverse Dampers

    CERN Document Server

    Rossi, V

    2002-01-01

    In the framework of the LHC project and the modifications of the SPS as its injector, I present the concept of global digital signal processing applied to a particle accelerator, using Field Programmable Gate Array (FPGA) technology. The approach of global digital synthesis implements in numerical form the architecture of a system, from the start up of a project and the very beginning of the signal flow. It takes into account both the known parameters and the future evolution, whenever possible. Due to the increased performance requirements of today's projects, the CAE design methodology becomes more and more necessary to handle successfully the added complexity and speed of modern electronic circuits. Simulation is performed both for behavioural analysis, to ensure conformity to functional requirements, and for time signal analysis (speed requirements). The digital notch filter with programmable delay for the SPS Transverse Damper is now fully operational with fixed target and LHC-type beams circulating in t...

  1. Delayed puberty in girls

    Science.gov (United States)

    ... sexual development - girls; Pubertal delay - girls; Constitutional delayed puberty ... In most cases of delayed puberty, growth changes just begin later than usual, sometimes called a late bloomer. Once puberty begins, it progresses normally. This pattern runs ...

  2. Delayed Puberty (For Teens)

    Science.gov (United States)

    ... Safe Videos for Educators Search English Español Delayed Puberty KidsHealth / For Teens / Delayed Puberty What's in this ... wonder if there's anything wrong. What Is Delayed Puberty? Puberty is the time when your body grows ...

  3. Sleep Control Game for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Sang Hoon Lee

    2016-01-01

    Full Text Available In wireless sensor networks (WSNs, each node controls its sleep to reduce energy consumption without sacrificing message latency. In this paper we apply the game theory, which is a powerful tool that explains how each individual acts for his or her own economic benefit, to analyze the optimal sleep schedule for sensor nodes. We redefine this sleep control game as a modified version of the Prisoner’s Dilemma. In the sleep control game, each node decides whether or not it wakes up for the cycle. Payoff functions of the sleep control game consider the expected traffic volume, network conditions, and the expected packet delay. According to the payoff function, each node selects the best wake-up strategy that may minimize the energy consumption and maintain the latency performance. To investigate the performance of our algorithm, we apply the sleep control game to X-MAC, which is one of the recent WSN MAC protocols. Our detailed packet level simulations confirm that the proposed algorithm can effectively reduce the energy consumption by removing unnecessary wake-up operations without loss of the latency performance.

  4. Interaction of sleep and emotional content on the production of false memories.

    Science.gov (United States)

    McKeon, Shannon; Pace-Schott, Edward F; Spencer, Rebecca M C

    2012-01-01

    Sleep benefits veridical memories, resulting in superior recall relative to off-line intervals spent awake. Sleep also increases false memory recall in the Deese-Roediger-McDermott (DRM) paradigm. Given the suggestion that emotional veridical memories are prioritized for consolidation over sleep, here we examined whether emotion modulates sleep's effect on false memory formation. Participants listened to semantically related word lists lacking a critical lure representing each list's "gist." Free recall was tested after 12 hours containing sleep or wake. The Sleep group recalled more studied words than the Wake group but only for emotionally neutral lists. False memories of both negative and neutral critical lures were greater following sleep relative to wake. Morning and Evening control groups (20-minute delay) did not differ ruling out circadian accounts for these differences. These results support the adaptive function of sleep in both promoting the consolidation of veridical declarative memories and in extracting unifying aspects from memory details.

  5. Interaction of sleep and emotional content on the production of false memories.

    Directory of Open Access Journals (Sweden)

    Shannon McKeon

    Full Text Available Sleep benefits veridical memories, resulting in superior recall relative to off-line intervals spent awake. Sleep also increases false memory recall in the Deese-Roediger-McDermott (DRM paradigm. Given the suggestion that emotional veridical memories are prioritized for consolidation over sleep, here we examined whether emotion modulates sleep's effect on false memory formation. Participants listened to semantically related word lists lacking a critical lure representing each list's "gist." Free recall was tested after 12 hours containing sleep or wake. The Sleep group recalled more studied words than the Wake group but only for emotionally neutral lists. False memories of both negative and neutral critical lures were greater following sleep relative to wake. Morning and Evening control groups (20-minute delay did not differ ruling out circadian accounts for these differences. These results support the adaptive function of sleep in both promoting the consolidation of veridical declarative memories and in extracting unifying aspects from memory details.

  6. The Sleeping Cerebellum.

    Science.gov (United States)

    Canto, Cathrin B; Onuki, Yoshiyuki; Bruinsma, Bastiaan; van der Werf, Ysbrand D; De Zeeuw, Chris I

    2017-05-01

    We sleep almost one-third of our lives and sleep plays an important role in critical brain functions like memory formation and consolidation. The role of sleep in cerebellar processing, however, constitutes an enigma in the field of neuroscience; we know little about cerebellar sleep-physiology, cerebro-cerebellar interactions during sleep, or the contributions of sleep to cerebellum-dependent memory consolidation. Likewise, we do not understand why cerebellar malfunction can lead to changes in the sleep-wake cycle and sleep disorders. In this review, we evaluate how sleep and cerebellar processing may influence one another and highlight which scientific routes and technical approaches could be taken to uncover the mechanisms underlying these interactions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Emotional memory processing is influenced by sleep quality.

    Science.gov (United States)

    Tempesta, Daniela; De Gennaro, Luigi; Natale, Vincenzo; Ferrara, Michele

    2015-07-01

    The recall of emotional memory is enhanced after sleep and is hindered by sleep deprivation. We used an emotional memory task to assess whether poor sleep quality, as well as sleep deprivation, may influence the accuracy of memory recognition, but also the affective tone associated with the memory. Seventy-five subjects, divided into poor sleeper (PS), good sleeper (GS), and sleep deprivation (SD) groups, completed two recall (R) sessions: R1, 1 h after the encoding phase; and R2, after one night of sleep for PS and GS groups and after one night of sleep deprivation for the SD group. During the encoding phase, the participants rated valence and arousal of 90 pictures. During R1 and R2, the participants first made a yes/no memory judgment of the 45 target pictures intermingled with 30 non-target pictures, then rated valence and arousal of each picture. Recognition accuracy was higher for the PS and GS groups compared to the SD group for all pictures. Emotional valence of the remembered pictures was more negative after sleep deprivation and poor quality sleep, while it was preserved after a good sleep. These results provide the first evidence that poor sleep quality negatively affects emotional valence of memories, within the context of preserved emotional memory consolidation. It is suggested that low sleep quality and lack of sleep may impose a more negative affective tone to memories. The reported effects are not to be ascribed to depressive mood, but to a specific influence of poor sleep quality. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Micro-arousals during nocturnal sleep.

    Science.gov (United States)

    Halász, P; Kundra, O; Rajna, P; Pál, I; Vargha, M

    1979-01-01

    In 8 young adult human subjects EEG- and polygraphic characteristics of transient shifts towards arousal (micro-arousal, MA) have been studied during sleep under five different experimental conditions in 40 night sessions. Out of the five applied experimental situations, two (psychostimulant application and sensory stimulation) resulted in a shift of the balance between the systems of sleep and arousal towards an increased activity of the arousal system, while an other condition (rebound following partial sleep deprivation) led to an opposite change to a rise in "sleep pressure". An inverse correlation has been found between the frequency of MA and the depth of sleep, a finding consistently observed in every subject and in every experimental situation. During the process of sleep periodic changes in the dispersity of MA could be seen; the number of MA-s decreased and increased according to the descending and ascending slope of the sleep cycles. During the ascending slope of cycles there was a coupling between the occurence of MA-s and the changes of phases. Increases in the level of activation and in sleep pressure did not influence the occurrence of MA-s. Increasing the tone of the arousal system in chemical way, or by means of enhancing the phasic sensory input resulted in a reduction of the difference between the number of MA on the descending and ascending slopes of cycles. During the phases of sleep, the spontaneous occurrence of MA-s went parallel with the possibility to evoke MA-s by sensory stimuli. These data show that MA is a regular phenomenon of nocturnal sleep; MA manifests itself as a result of phasic functioning of the reticular arousal system and plays a role in the organization of those periods of the sleep cycle, which tend toward arousal. It is suggested that MA-phenomenon is considered a standard measure of sleep and that it could represent an indicator of the function of the arousal system controlled by external or internal mechanisms during

  9. Post-irradiation DNA synthesis inhibition and G2 phase delay in radiosensitive body cells from non-Hodgkin's lymphoma patients: An indication of cell cycle defects

    International Nuclear Information System (INIS)

    Hannan, Mohammed A.; Kunhi, Mohammed; Einspenner, Michael; Khan, Bashir A.; Al-Sedairy, Sultan

    1994-01-01

    In the present study, both post-irradiation DNA synthesis and G 2 phase accumulation were analyzed in lymphoblastoid cell lines (LCLs) and fibroblast cell strains derived from (Saudi) patients with non-Hodgkin's lymphoma (NHL), ataxia telangiectasia (AT), AT heterozygotes and normal subjects. A comparison of the percent DNA synthesis inhibition (assayed by 3 H-thymidine uptake 30 min after irradiation), and a 24 h post-irradiation G 2 phase accumulation determined by flow cytometry placed the AT heterozygotes and the NHL patients in an intermediate position between the normal subjects (with maximum DNA synthesis inhibition and minimum G 2 phase accumulation) and the AT homozygotes (with minimum DNA synthesis inhibition and maximum G 2 accumulation). The similarity between AT heterozygotes and the NHL patients with respect to the two parameters studied after irradiation was statistically significant. The data indicating a moderate abnormality in the control of cell cycle progression after irradiation in the LCLs and fibroblasts from NHL patients may explain the enhanced cellular and chromosomal radiosensitivity in these patients reported by us earlier. In addition to demonstrating a link between cell cycle abnormality and radiosensitivity as a possible basis for cancer susceptibility, particularly in the NHL patients, the present studies emphasized the usefulness of the assay for 24 h post-irradiation G 2 phase accumulation developed elsewhere in characterizing AT heterozygote-like cell cycle anomaly in cancer patients irrespective of whether they carried the AT gene or any other affecting the cell cycle

  10. Sleep from an islamic perspective

    OpenAIRE

    Ahmed S BaHammam

    2011-01-01

    Sleep medicine is a relatively new scientific specialty. Sleep is an important topic in Islamic literature, and the Quran and Hadith discuss types of sleep, the importance of sleep, and good sleep practices. Islam considers sleep as one of the signs of the greatness of All?h (God) and encourages followers to explore this important sign. The Quran describes different types of sleep, and these correspond with sleep stages identified by modern science. The Quran discusses the beneficial effects ...

  11. [Sleep disorders among physicians on shift work].

    Science.gov (United States)

    Schlafer, O; Wenzel, V; Högl, B

    2014-11-01

    Sleep disorders in physicians who perform shift work can result in increased risks of health problems that negatively impact performance and patient safety. Even those who cope well with shift work are likely to suffer from sleep disorders. The aim of this manuscript is to discuss possible causes, contributing factors and consequences of sleep disorders in physicians and to identify measures that can improve adaptation to shift work and treatment strategies for shift work-associated sleep disorders. The risk factors that influence the development of sleep disorders in physicians are numerous and include genetic factors (15 % of the population), age (> 50 years), undiagnosed sleep apnea,, alcohol abuse as well as multiple stress factors inherent in clinical duties (including shift work), research, teaching and family obligations. Several studies have reported an increased risk for medical errors in sleep-deprived physicians. Shift workers have an increased risk for psychiatric and cardiovascular diseases and shift work may also be a contributing factor to cancer. A relationship has been reported not only with sleep deprivation and changes in food intake but also with diabetes mellitus, obesity, hypertension and coronary heart disease. Nicotine and alcohol consumption are more frequent among shift workers. Increased sickness and accident rates among physicians when commuting (especially after night shifts) have a socioeconomic impact. In order to reduce fatigue and to improve performance, short naps during shiftwork or naps plus caffeine, have been proposed as coping strategies; however, napping during adverse circadian phases is less effective, if not impossible when unable to fall asleep. Bright and blue light supports alertness during a night shift. After shiftwork, direct sunlight exposure to the retina can be avoided by using dark sunglasses or glasses with orange lenses for commuting home. The home environment for daytime sleeping after a night shift should be

  12. Sleep and sleep disorders in Don Quixote.

    Science.gov (United States)

    Iranzo, Alex; Santamaria, Joan; de Riquer, Martín

    2004-01-01

    In Don Quijote de la Mancha, Miguel de Cervantes presents Don Quixote as an amazing character of the 17th century who suffers from delusions and illusions, believing himself to be a medieval knight errant. Besides this neuropsychiatric condition, Cervantes included masterful descriptions of several sleep disorders such as insomnia, sleep deprivation, disruptive loud snoring and rapid eye movement sleep behaviour disorder. In addition, he described the occurrence of physiological, vivid dreams and habitual, post-prandial sleepiness--the siesta. Cervantes' concept of sleep as a passive state where all cerebral activities are almost absent is in conflict with his description of abnormal behaviours during sleep and vivid, fantastic dreams. His concept of sleep was shared by his contemporary, Shakespeare, and could have been influenced by the reading of the classical Spanish book of psychiatry Examen de Ingenios (1575).

  13. Optimal control of M/M/1 two-phase queueing system with state-dependent arrival rate, server breakdowns, delayed repair, and N-policy

    Science.gov (United States)

    Rao, Hanumantha; Kumar, Vasanta; Srinivasa Rao, T.; Srinivasa Kumar, B.

    2018-04-01

    In this paper, we examine a two-stage queueing system where the arrivals are Poisson with rate depends on the condition of the server to be specific: vacation, pre-service, operational or breakdown state. The service station is liable to breakdowns and deferral in repair because of non-accessibility of the repair facility. The service is in two basic stages, the first being bulk service to every one of the customers holding up on the line and the second stage is individual to each of them. The server works under N-policy. The server needs preliminary time (startup time) to begin batch service after a vacation period. Startup times, uninterrupted service times, the length of each vacation period, delay times and service times follows an exponential distribution. The closed form of expressions for the mean system size at different conditions of the server is determined. Numerical investigations are directed to concentrate the impact of the system parameters on the ideal limit N and the minimum base expected unit cost.

  14. Sleep Deprivation and Time-Based Prospective Memory.

    Science.gov (United States)

    Esposito, Maria José; Occhionero, Miranda; Cicogna, PierCarla

    2015-11-01

    To evaluate the effect of sleep deprivation on time-based prospective memory performance, that is, realizing delayed intentions at an appropriate time in the future (e.g., to take a medicine in 30 minutes). Between-subjects experimental design. The experimental group underwent 24 h of total sleep deprivation, and the control group had a regular sleep-wake cycle. Participants were tested at 08:00. Laboratory. Fifty healthy young adults (mean age 22 ± 2.1, 31 female). 24 h of total sleep deprivation. Participants were monitored by wrist actigraphy for 3 days before the experimental session. The following cognitive tasks were administered: one time-based prospective memory task and 3 reasoning tasks as ongoing activity. Objective and subjective vigilance was assessed by the psychomotor vigilance task and a visual analog scale, respectively. To measure the time-based prospective memory task we assessed compliance and clock checking behavior (time monitoring). Sleep deprivation negatively affected time-based prospective memory compliance (P sleep deprivation on human behavior, particularly the ability to perform an intended action after a few minutes. Sleep deprivation strongly compromises time-based prospective memory compliance but does not affect time check frequency. Sleep deprivation may impair the mechanism that allows the integration of information related to time monitoring with the prospective intention. © 2015 Associated Professional Sleep Societies, LLC.

  15. Sleep disturbances in Parkinsonism.

    Science.gov (United States)

    Askenasy, J J M

    2003-02-01

    The present article is meant to suggest an approach to the guidelines for the therapy of sleep disturbances in Parkinson's Disease (PD) patients.The factors affecting the quality of life in PD patients are depression, sleep disturbances and dependence. A large review of the literature on sleep disturbances in PD patients, provided the basis for the following classification of the sleep-arousal disturbances in PD patients. We suggest a model based on 3 steps in the treatment of sleep disturbances in PD patients. This model allowing the patient, the spouse or the caregiver a quiet sleep at night, may postpone the retirement and the institutionalization of the PD patient. I. Correct diagnosis of sleep disorders based on detailed anamnesis of the patient and of the spouse or of the caregiver. One week recording on a symptom diary (log) by the patient or the caregiver. Correct diagnosis of sleep disorders co morbidities. Selection of the most appropriate sleep test among: polysomnography (PSG), multiple sleep latency test (MSLT), multiple wake latency test (MWLT), Epworth Sleepiness Scale, actigraphy or video-PSG. II. The nonspecific therapeutic approach consists in: a) Checking the sleep effect on motor performance, is it beneficial, worse or neutral. b) Psycho-physical assistance. c) Dopaminergic adjustment is necessary owing to the progression of the nigrostriatal degeneration and the increased sensitivity of the terminals, which alter the normal modulator mechanisms of the motor centers in PD patients. Among the many neurotransmitters of the nigro-striatal pathway one can distinguish two with a major influence on REM and NonREM sleep. REM sleep corresponds to an increased cholinergic receptor activity and a decreased dopaminergic activity. This is the reason why REM sleep deprivation by suppressing cholinergic receptor activity ameliorates PD motor symptoms. L-Dopa and its agonists by suppressing cholinergic receptors suppress REM sleep. The permanent adjustment

  16. Auditory feedback blocks memory benefits of cueing during sleep.

    Science.gov (United States)

    Schreiner, Thomas; Lehmann, Mick; Rasch, Björn

    2015-10-28

    It is now widely accepted that re-exposure to memory cues during sleep reactivates memories and can improve later recall. However, the underlying mechanisms are still unknown. As reactivation during wakefulness renders memories sensitive to updating, it remains an intriguing question whether reactivated memories during sleep also become susceptible to incorporating further information after the cue. Here we show that the memory benefits of cueing Dutch vocabulary during sleep are in fact completely blocked when memory cues are directly followed by either correct or conflicting auditory feedback, or a pure tone. In addition, immediate (but not delayed) auditory stimulation abolishes the characteristic increases in oscillatory theta and spindle activity typically associated with successful reactivation during sleep as revealed by high-density electroencephalography. We conclude that plastic processes associated with theta and spindle oscillations occurring during a sensitive period immediately after the cue are necessary for stabilizing reactivated memory traces during sleep.

  17. Why are seizures rare in rapid eye movement sleep? Review of the frequency of seizures in different sleep stages.

    Science.gov (United States)

    Ng, Marcus; Pavlova, Milena

    2013-01-01

    Since the formal characterization of sleep stages, there have been reports that seizures may preferentially occur in certain phases of sleep. Through ascending cholinergic connections from the brainstem, rapid eye movement (REM) sleep is physiologically characterized by low voltage fast activity on the electroencephalogram, REMs, and muscle atonia. Multiple independent studies confirm that, in REM sleep, there is a strikingly low proportion of seizures (~1% or less). We review a total of 42 distinct conventional and intracranial studies in the literature which comprised a net of 1458 patients. Indexed to duration, we found that REM sleep was the most protective stage of sleep against focal seizures, generalized seizures, focal interictal discharges, and two particular epilepsy syndromes. REM sleep had an additional protective effect compared to wakefulness with an average 7.83 times fewer focal seizures, 3.25 times fewer generalized seizures, and 1.11 times fewer focal interictal discharges. In further studies REM sleep has also demonstrated utility in localizing epileptogenic foci with potential translation into postsurgical seizure freedom. Based on emerging connectivity data in sleep, we hypothesize that the influence of REM sleep on seizures is due to a desynchronized EEG pattern which reflects important connectivity differences unique to this sleep stage.

  18. Predictors of poor sleep quality among Lebanese university students: association between evening typology, lifestyle behaviors, and sleep habits

    Directory of Open Access Journals (Sweden)

    Kabrita CS

    2014-01-01

    Full Text Available Colette S Kabrita,1 Theresa A Hajjar-Muça,2 Jeanne F Duffy31Department of Sciences, 2Department of Mathematics and Statistics, Faculty of Natural and Applied Sciences, Notre Dame University – Louaize, Zouk Mosbeh, Lebanon; 3Division of Sleep Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USAAbstract: Adequate, good night sleep is fundamental to well-being and is known to be influenced by myriad biological and environmental factors. Given the unavailability of sleep data about Lebanon, the cultural shifts and socioeconomic pressures that have affected many aspects of society, particularly for students and working adults, as well as our understanding of sleep in university students in other countries, we conducted a national study to assess sleep quality and factors contributing to sleep and general health in a culture-specific context. A self-filled questionnaire, inquiring about sociodemographics, health-risk behaviors, personal health, and evaluating sleep quality and chronotype using standard scales was completed by 540 students at private and public universities in Lebanon. Overall, they reported sleeping 7.95±1.34 hours per night, although 12.3% reported sleeping <6.5 hours and more than half scored in the poor-sleeper category on the Pittsburgh Sleep Quality Index (PSQI. Sleep timing differed markedly between weekdays and weekends, with bedtimes and wake-up times delayed by 1.51 and 2.43 hours, respectively, on weekends. While most scored in the "neither type" category on the Morningness–Eveningness Questionnaire (MEQ, 24.5% were evening types and 7.3% were morning types. MEQ score was significantly correlated with smoking behavior and daily study onset, as well as with PSQI score, with eveningness associated with greater number of cigarettes, later study times, and poor sleep. We conclude that the prevalence of poor sleep quality among Lebanese university students is associated

  19. Speech and Language Delay

    Science.gov (United States)

    ... OTC Relief for Diarrhea Home Diseases and Conditions Speech and Language Delay Condition Speech and Language Delay Share Print Table of Contents1. ... Treatment6. Everyday Life7. Questions8. Resources What is a speech and language delay? A speech and language delay ...

  20. First Delayed Resection Findings After Irreversible Electroporation (IRE) of Human Localised Renal Cell Carcinoma (RCC) in the IRENE Pilot Phase 2a Trial

    Energy Technology Data Exchange (ETDEWEB)

    Wendler, Johann Jakob, E-mail: johann.wendler@med.ovgu.de [Otto von Guericke University of Magdeburg, Department of Urology, University Hospital (Germany); Ricke, Jens, E-mail: jens.Ricke@med.ovgu.de; Pech, Maciej, E-mail: macej.pech@med.ovgu.de; Fischbach, Frank, E-mail: frank.fischbach@med.ovgu.de; Jürgens, Julian, E-mail: julian.juergens@med.ovgu.de [University of Magdeburg, Department of Radiology (Germany); Siedentopf, Sandra, E-mail: sandra.siedentopf@med.ovgu.de; Roessner, Albert, E-mail: albert.roessner@med.ovgu.de [University of Magdeburg, Institute of Pathology (Germany); Porsch, Markus, E-mail: markus.porsch@med.ovgu.de; Baumunk, Daniel, E-mail: daniel.baumunk@med.ovgu.de; Schostak, Martin, E-mail: martin.schostak@med.ovgu.de [Otto von Guericke University of Magdeburg, Department of Urology, University Hospital (Germany); Köllermann, Jens, E-mail: jens.koellermann@sana.de [Sana Klinikum Offenbach Am Main, Institute of Pathology (Germany); Liehr, Uwe-Bernd, E-mail: uwe-bernd.liehr@med.ovgu.de [Otto von Guericke University of Magdeburg, Department of Urology, University Hospital (Germany)

    2016-02-15

    IntroductionIt is postulated that focal IRE affords complete ablation of soft-tissue tumours while protecting the healthy peritumoral tissue. Therefore, IRE may be an interesting option for minimally invasive, kidney-tissue-sparing, non-thermal ablation of renal tumours.AimWith this current pilot study (“IRENE trial”), we present the first detailed histopathological data of IRE of human RCC followed by delayed tumour resection. The aim of this interim analysis of the first three patients was to investigate the ablation efficiency of percutaneous image-guided focal IRE in RCC, to assess whether a complete ablation of T1a RCC and tissue preservation with the NanoKnife system is possible and to decide whether the ablation parameters need to be altered.MethodsFollowing resection 4 weeks after percutaneous IRE, the success of ablation and detailed histopathological description were used to check the ablation parameters.ResultsThe IRE led to a high degree of damage to the renal tumours (1 central, 2 peripheral; size range 15–17 mm). The postulated homogeneous, isomorphic damage was only partly confirmed. We found a zonal structuring of the ablation zone, negative margins and, enclosed within the ablation zone, very small tumour residues of unclear malignancy.ConclusionAccording to these initial, preliminary study results of the first three renal cases, a new zonal distribution of IRE damage was described and the curative intended, renal saving focal ablation of localised RCC below <3 cm by percutaneous IRE by the NanoKnife system appears to be possible, but needs further, systematic evaluation for this treatment method and treatment protocol.

  1. Two-week course of preoperative chemoradiotherapy followed by delayed surgery for rectal cancer: A phase II multi-institutional clinical trial (KROG 11-02)

    International Nuclear Information System (INIS)

    Lee, Jong Hoon; Kim, Jun-Gi; Oh, Seong Taek; Lee, Myung Ah; Chun, Hoo Geun; Kim, Dae Yong; Kim, Tae Hyun; Kim, Sun Young; Baek, Ji Yeon; Park, Ji Won; Oh, Jae Hwan; Park, Hee Chul; Choi, Doo Ho; Park, Young Suk; Kim, Hee Cheol; Chie, Eui Kyu; Jang, Hong Seok

    2014-01-01

    Purpose: The aim of this study was to evaluate the efficacy and safety of a two-week schedule of radiotherapy with oral capecitabine in locally advanced rectal cancer. Methods and materials: Eighty patients with rectal cancer located in the mid to low rectum, staged cT3-4N0-2M0, were prospectively enrolled. They underwent preoperative chemoradiotherapy and delayed surgery 6–8 weeks after the completion of radiation therapy. A radiation dose of 33 Gy in 10 fractions was delivered to the pelvis for 2 weeks. One cycle of oral capecitabine was administered at a dose of 1650 mg/m 2 /day during radiotherapy. Tumor response and toxicity were the study endpoints. This study was registered at ClinicalTrials.gov (number, (NCT01431599)). Results: All included patients underwent total mesorectal excisions including 12 cases of robot assisted surgery and 50 cases of laparoscopic surgery. Of the 80 patients, 27 (33.8%) achieved downstaging (ypT0-2N0) of a rectal tumor and 11 (13.8%) had a pathologically complete response (ypCR). Downstaging rates were 45% for T classification and 65% for N classification. Sphincter saving was achieved in 73 (91.3%) of the 80 patients. Of the 80 patients, 3 (3.8%) experienced grade 3 hematologic toxicity, and 2 (2.5%) had grade 3 postoperative complications such as ileus and wound dehiscence. There was no grade 4 toxicity. Conclusion: A two-week schedule of radiotherapy with oral capecitabine in locally advanced rectal cancer patients showed low toxicity profiles and promising results in terms of tumor response

  2. Two-week course of preoperative chemoradiotherapy followed by delayed surgery for rectal cancer: a phase II multi-institutional clinical trial (KROG 11-02).

    Science.gov (United States)

    Lee, Jong Hoon; Kim, Jun-Gi; Oh, Seong Taek; Lee, Myung Ah; Chun, Hoo Geun; Kim, Dae Yong; Kim, Tae Hyun; Kim, Sun Young; Baek, Ji Yeon; Park, Ji Won; Oh, Jae Hwan; Park, Hee Chul; Choi, Doo Ho; Park, Young Suk; Kim, Hee Cheol; Chie, Eui Kyu; Jang, Hong Seok

    2014-01-01

    The aim of this study was to evaluate the efficacy and safety of a two-week schedule of radiotherapy with oral capecitabine in locally advanced rectal cancer. Eighty patients with rectal cancer located in the mid to low rectum, staged cT3-4N0-2M0, were prospectively enrolled. They underwent preoperative chemoradiotherapy and delayed surgery 6-8 weeks after the completion of radiation therapy. A radiation dose of 33 Gy in 10 fractions was delivered to the pelvis for 2 weeks. One cycle of oral capecitabine was administered at a dose of 1650 mg/m(2)/day during radiotherapy. Tumor response and toxicity were the study endpoints. This study was registered at ClinicalTrials.gov (number, NCT01431599). All included patients underwent total mesorectal excisions including 12 cases of robot assisted surgery and 50 cases of laparoscopic surgery. Of the 80 patients, 27 (33.8%) achieved downstaging (ypT0-2N0) of a rectal tumor and 11 (13.8%) had a pathologically complete response (ypCR). Downstaging rates were 45% for T classification and 65% for N classification. Sphincter saving was achieved in 73 (91.3%) of the 80 patients. Of the 80 patients, 3 (3.8%) experienced grade 3 hematologic toxicity, and 2 (2.5%) had grade 3 postoperative complications such as ileus and wound dehiscence. There was no grade 4 toxicity. A two-week schedule of radiotherapy with oral capecitabine in locally advanced rectal cancer patients showed low toxicity profiles and promising results in terms of tumor response. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  3. Safe Sleep for Babies

    Science.gov (United States)

    ... 5 MB] Read the MMWR Science Clips Safe Sleep for Babies Eliminating hazards Recommend on Facebook Tweet ... Page Problem Every year, there are thousands of sleep-related deaths among babies. View large image and ...

  4. Teenagers and sleep

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000872.htm Teenagers and sleep To use the sharing features on this page, ... need. What Makes it Hard for Teens to Sleep? Several factors make it hard for teens to ...

  5. Obstructive Sleep Apnea

    Medline Plus

    Full Text Available ... OSA causes daytime drowsiness that can result in accidents, lost productivity and relationship problems. The National Sleep ... 30 apneas during a seven-hour sleep. In severe cases, periods of not breathing may last for ...

  6. Isolated sleep paralysis

    Science.gov (United States)

    ... T, Dement WC, eds. Principles and Practice of Sleep Medicine. 6th ed. Philadelphia, PA: Elsevier; 2017:chap 103. ... Blaivas, DO, Division of Pulmonary, Critical Care, and Sleep Medicine, VA New Jersey Health Care System, Clinical Assistant ...

  7. Problems sleeping during pregnancy

    Science.gov (United States)

    ... T, Dement WC, eds. Principles and Practice of Sleep Medicine . 6th ed. Philadelphia, PA: Elsevier; 2017:chap 156. Ibrahim S, Foldvary-Shaefer N. Sleep disorders in pregnancy: implications, evaluation, and treatment. Neurologic ...

  8. Sleep Apnea Facts

    Science.gov (United States)

    ... include being overweight and having a large neck. Losing even 10 percent of body weight can help reduce the number of times a person with sleep apnea stops breathing during sleep. African-Americans, Pacific ...

  9. Obstructive Sleep Apnea

    Medline Plus

    Full Text Available ... The National Sleep Foundation estimates that 18 million adults have obstructive sleep apnea and it is likely ... Maxillofacial Surgeon (OMS). An estimated 18-20 million adults in the US suffer from OSA. What Is ...

  10. Obstructive sleep apnea - adults

    Science.gov (United States)

    ... SM. Obstructive sleep apnea: clinical features, evaluation, and principles of management. In: Kryger M, Roth T, Dement WC, eds. Principles and Practice of Sleep Medicine . 6th ed. Philadelphia, ...

  11. Obstructive Sleep Apnea

    Medline Plus

    Full Text Available ... sleep apnea (OSA) is a serious and even life-threatening condition. The risks of undiagnosed OSA are ... sleep apnea (OSA) is a serious and even life-threatening condition. The risks of undiagnosed OSA are ...

  12. Sleeping during Pregnancy

    Science.gov (United States)

    ... Fitness Diseases & Conditions Infections Drugs & Alcohol School & Jobs Sports Expert Answers (Q&A) Staying Safe Videos for Educators Search English Español Sleeping During Pregnancy KidsHealth / For Parents / Sleeping During Pregnancy What's in ...

  13. Overexpression of catalase delays G0/G1- to S-phase transition during cell cycle progression in mouse aortic endothelial cells.

    Science.gov (United States)

    Onumah, Ogbeyalu E; Jules, George E; Zhao, Yanfeng; Zhou, LiChun; Yang, Hong; Guo, ZhongMao

    2009-06-15

    Although it is understood that hydrogen peroxide (H(2)O(2)) promotes cellular proliferation, little is known about its role in endothelial cell cycle progression. To assess the regulatory role of endogenously produced H(2)O(2) in cell cycle progression, we studied the cell cycle progression in mouse aortic endothelial cells (MAECs) obtained from mice overexpressing a human catalase transgene (hCatTg), which destroys H(2)O(2). The hCatTg MAECs displayed a prolonged doubling time compared to wild-type controls (44.0 +/- 4.7 h versus 28.6 +/- 0.8 h, pcatalase inhibitor, prevented the observed diminished growth rate in hCatTg MAECs. Inhibition of catalase activity with aminotriazole abrogated catalase overexpression-induced antiproliferative action. Flow cytometry analysis indicated that the prolonged doubling time was principally due to an extended G(0)/G(1) phase in hCatTg MAECs compared to the wild-type cells (25.0 +/- 0.9 h versus 15.9 +/- 1.4 h, pinhibitors, p21 and p27, which inhibit the Cdk activity required for the G(0)/G(1)- to S-phase transition. Knockdown of p21 and/or p27 attenuated the antiproliferative effect of catalase overexpression in MAECs. These results, together with the fact that catalase is an H(2)O(2) scavenger, suggest that endogenously produced H(2)O(2) mediates MAEC proliferation by fostering the transition from G(0)/G(1) to S phase.

  14. Parental professional help-seeking for infant sleep.

    Science.gov (United States)

    Hsu, Pei-Wen; Wu, Wei-Wen; Tung, Yi-Ching; Thomas, Karen A; Tsai, Shao-Yu

    2017-12-01

    To explore the perceptions and experiences of parental professional help-seeking for infant sleep and sleep-related concerns. Infant sleep is a frequent concern for parents. However, very little is known about the reasons parents seek, do not seek or delay seeking professional attention about their concerns related to infant sleep. A qualitative study design was used. Twenty audio-taped interviews with parents of healthy 12-month-old infants were conducted at a university-affiliated hospital or parents' homes depending on where parents felt more comfortable discussing their personal views and medical help-seeking experiences. Thematic content analysis was performed to determine specific patterns and similarities within and between interview data. Three main themes developed from the interviews were as follows: (i) uncertainty about infant sleep; (ii) I can handle infant sleep; and (iii) I am not satisfied with the professional services provided for infant sleep. Overall, parents knew little about or misunderstood infant sleep behaviours. Lack of proper information and knowledge about infant sleep influenced parents' motivation for professional help-seeking and help-receiving. Parents who have consulted a healthcare professional but received unsatisfactory responses, such as an ambivalent attitude or insufficient assessment, reported being less motivated or unwilling to seek medical help again. Our study demonstrates the complexity of parental professional help-seeking and receiving for infant sleep. Findings suggest that parents perceive a wide range of barriers that influence the likelihood that they will seek professional advice for infant sleep. Reducing knowledge barriers and providing adequate attention at all well-infant visits would facilitate parental use of healthcare services to manage problematic infant sleep behaviours. © 2017 John Wiley & Sons Ltd.

  15. A Novel Energy Saving Algorithm with Frame Response Delay Constraint in IEEE 802.16e

    Science.gov (United States)

    Nga, Dinh Thi Thuy; Kim, Mingon; Kang, Minho

    Sleep-mode operation of a Mobile Subscriber Station (MSS) in IEEE 802.16e effectively saves energy consumption; however, it induces frame response delay. In this letter, we propose an algorithm to quickly find the optimal value of the final sleep interval in sleep-mode in order to minimize energy consumption with respect to a given frame response delay constraint. The validations of our proposed algorithm through analytical results and simulation results suggest that our algorithm provide a potential guidance to energy saving.

  16. Applying behavioral insights to delay school start times.

    Science.gov (United States)

    Kohl Malone, Susan; Ziporyn, Terra; Buttenheim, Alison M

    2017-12-01

    Healthy People 2020 established a national objective to increase the proportion of 9th-to-12th-grade students reporting sufficient sleep. A salient approach for achieving this objective is to delay middle and high school start times. Despite decades of research supporting the benefits of delayed school start times on adolescent sleep, health, and well-being, progress has been slow. Accelerating progress will require new approaches incorporating strategies that influence how school policy decisions are made. In this commentary, we introduce four strategies that influence decision-making processes and demonstrate how they can be applied to efforts aimed at changing school start time policies. Copyright © 2017 National Sleep Foundation. All rights reserved.

  17. Investigating the Efficacy of Sleep Hygiene Education on Improving Sleep Disorders in Shahid Sadoughi Hospital Nurses

    Directory of Open Access Journals (Sweden)

    A Hazeri

    2015-07-01

    Methods:This is an analytical study with Field Trail method and pre- and post-style. Data were collected using a questionnaire consisting of demographic information, ESS, SMII, and ISI. In the first phase of the study, questionnaires were distributed among 207 nurses out of whom 100 nurses were diagnosed with sleep disorder. Eventually after the training period, the data from 66 questionnaires were analysed, using SPSS20 software with Paired T-test and ANOVA. Results:The first part of the findings showed that 48.3 percent of the nurses have sleep disorder. Findings also indicated that factors such as age, gender, marital status, work experience, number of children, type of shift work and job satisfaction did not have significant statistical impact on sleep disorder. The second part measured improvement of sleep disorders related to sleep hygiene education for nurses. Results revealed a better condition of sleep disorder among the participants after their education around sleep hygiene. Although there wasstatistically no significant relationship between pre- and post-training sleep disorder scores, given the small p-value it can be said that a marginal meaningful relationship does exist.

  18. Validation and Application of a New Reversed Phase HPLC Method for In Vitro Dissolution Studies of Rabeprazole Sodium in Delayed-Release Tablets

    Directory of Open Access Journals (Sweden)

    Md. Saddam Nawaz

    2013-01-01

    Full Text Available The purpose of this study was to develop and validate a new reversed phase high performance liquid chromatographic (RP-HPLC method to quantify in vitro dissolution assay of rabeprazole sodium in pharmaceutical tablet dosage form. Method development was performed on C 18, 100×4.6 mm ID, and 10 μm particle size column, and injection volume was 20 μL using a diode array detector (DAD to monitor the detection at 280 nm. The mobile phase consisted of buffer: acetonitrile at a ratio of 60 : 40 (v/v, and the flow rate was maintained at 1.0 mL/min. The method was validated in terms of suitability, linearity, specificity, accuracy, precision, stability, and sensitivity. Linearity was observed over the range of concentration 0.05–12.0 μg/mL, and the correlation coefficient was found excellent >0.999. The method was specific with respect to rabeprazole sodium, and the peak purity was found 99.99%. The method was precise and had relative standard deviations (RSD less than 2%. Accuracy was found in the range of 99.9 to 101.9%. The method was robust in different variable conditions and reproducible. This proposed fast, reliable, cost-effective method can be used as quality control tool for the estimation of rabeprazole sodium in routine dissolution test analysis.

  19. Non-contact assessment of obstructive sleep apnea cardiovascular biomarkers using photoplethysmography imaging

    Science.gov (United States)

    Amelard, Robert; Pfisterer, Kaylen J.; Jagani, Shubh; Clausi, David A.; Wong, Alexander

    2018-02-01

    Obstructive sleep apnea (OSA) affects 20% of the adult population, and is associated with cardiovascular and cognitive morbidities. However, it is estimated that up to 80% of treatable OSA cases remain undiagnosed. Cur- rent methods for diagnosing OSA are expensive, labor-intensive, and involve uncomfortable wearable sensors. This study explored the feasibility of non-contact biophotonic assessment of OSA cardiovascular biomarkers via photoplethysmography imaging (PPGI). In particular, PPGI was used to monitor the hemodynamic response to obstructive respiratory events. Sleep apnea onset was simulated using Muller's maneuver in which breathing was obstructed by a respiratory clamp. A custom PPGI system, coded hemodynamic imaging (CHI), was positioned 1 m above the bed and illuminated the participant's head with 850 nm light, providing non-intrusive illumination for night-time monitoring. A video was recorded before, during and following an apnea event at 60 fps, yielding 17 ms temporal resolution. Per-pixel absorbance signals were extracted using a Beer-Lambert derived light transport model, and subsequently denoised. The extracted hemodynamic signal exhibited dynamic temporal modulation during and following the apnea event. In particular, the pulse wave amplitude (PWA) decreased during obstructed breathing, indicating vasoconstriction. Upon successful inhalation, the PWA gradually increased toward homeostasis following a temporal phase delay. This temporal vascular tone modulation provides insight into autonomic and vascular response, and may be used to assess sleep apnea using non-contact biophotonic imaging.

  20. Sleep and Metabolism: An Overview

    Directory of Open Access Journals (Sweden)

    Sunil Sharma

    2010-01-01

    Full Text Available Sleep and its disorders are increasingly becoming important in our sleep deprived society. Sleep is intricately connected to various hormonal and metabolic processes in the body and is important in maintaining metabolic homeostasis. Research shows that sleep deprivation and sleep disorders may have profound metabolic and cardiovascular implications. Sleep deprivation, sleep disordered breathing, and circadian misalignment are believed to cause metabolic dysregulation through myriad pathways involving sympathetic overstimulation, hormonal imbalance, and subclinical inflammation. This paper reviews sleep and metabolism, and how sleep deprivation and sleep disorders may be altering human metabolism.

  1. Sleep deprivation in Depression : What do we know, where do we go?

    NARCIS (Netherlands)

    Wirz-Justice, A; Van den Hoofdakker, RH

    1999-01-01

    Manipulations of the sleep-wake cycle, whether of duration (total or partial sleep deprivation [SD]) or timing (partial SD, phase advance), have profound and rapid effects on depressed mood in 60% of all diagnostic subgroups of affective disorders. Relapse after recovery sleep is less when patients

  2. The Functions of Sleep

    Directory of Open Access Journals (Sweden)

    Samson Z Assefa

    2015-08-01

    Full Text Available Sleep is a ubiquitous component of animal life including birds and mammals. The exact function of sleep has been one of the mysteries of biology. A considerable number of theories have been put forward to explain the reason(s for the necessity of sleep. To date, while a great deal is known about what happens when animals sleep, there is no definitive comprehensive explanation as to the reason that sleep is an inevitable part of animal functioning. It is well known that sleep is a homeostatically regulated body process, and that prolonged sleep deprivation is fatal in animals. In this paper, we present some of the theories as to the functions of sleep and provide a review of some hypotheses as to the overall physiologic function of sleep. To better understand the purpose for sleeping, we review the effects of sleep deprivation on physical, neurocognitive and psychic function. A better understanding of the purpose for sleeping will be a great advance in our understanding of the nature of the animal kingdom, including our own.

  3. Treatments for Sleep Changes

    Science.gov (United States)

    ... Contributing medical factors Non-drug strategies Medications Common sleep changes Many people with Alzheimer’s experience changes in ... at night. Subscribe now Non-drug treatments for sleep changes Non-drug treatments aim to improve sleep ...

  4. Sleep Talking (Somniloquy)

    Science.gov (United States)

    ... radius (in miles): 10 25 50 Share: Essentials in Sleep Insomnia Overview & Facts Symptoms & Causes Diagnosis & Self Tests Treatment ... Sleep talking is very common. It is reported in 50% of young children. About 5% of adults are reported to talk in their sleep. It ...

  5. Sleep, School Performance, and a School-Based Intervention among School-Aged Children: A Sleep Series Study in China

    Science.gov (United States)

    Li, Shenghui; Arguelles, Lester; Jiang, Fan; Chen, Wenjuan; Jin, Xingming; Yan, Chonghuai; Tian, Ying; Hong, Xiumei; Qian, Ceng; Zhang, Jun; Wang, Xiaobin; Shen, Xiaoming

    2013-01-01

    Background Sufficient sleep during childhood is essential to ensure a transition into a healthy adulthood. However, chronic sleep loss continues to increase worldwide. In this context, it is imperative to make sleep a high-priority and take action to promote sleep health among children. The present series of studies aimed to shed light on sleep patterns, on the longitudinal association of sleep with school performance, and on practical intervention strategy for Chinese school-aged children. Methods and Findings A serial sleep researches, including a national cross-sectional survey, a prospective cohort study, and a school-based sleep intervention, were conducted in China from November 2005 through December 2009. The national cross-sectional survey was conducted in 8 cities and a random sample of 20,778 children aged 9.0±1.61 years participated in the survey. The five-year prospective cohort study included 612 children aged 6.8±0.31 years. The comparative cross-sectional study (baseline: n = 525, aged 10.80±0.41; post-intervention follow-up: n = 553, aged 10.81±0.33) was undertaken in 6 primary schools in Shanghai. A battery of parent and teacher reported questionnaires were used to collect information on children’s sleep behaviors, school performance, and sociodemographic characteristics. The mean sleep duration was 9.35±0.77 hours. The prevalence of daytime sleepiness was 64.4% (sometimes: 37.50%; frequently: 26.94%). Daytime sleepiness was significantly associated with impaired attention, learning motivation, and particularly, academic achievement. By contrast, short sleep duration only related to impaired academic achievement. After delaying school start time 30 minutes and 60 minutes, respectively, sleep duration correspondingly increased by 15.6 minutes and 22.8 minutes, respectively. Moreover, intervention significantly improved the sleep duration and daytime sleepiness. Conclusions Insufficient sleep and daytime sleepiness commonly existed and

  6. Sleep, school performance, and a school-based intervention among school-aged children: a sleep series study in China.

    Science.gov (United States)

    Li, Shenghui; Arguelles, Lester; Jiang, Fan; Chen, Wenjuan; Jin, Xingming; Yan, Chonghuai; Tian, Ying; Hong, Xiumei; Qian, Ceng; Zhang, Jun; Wang, Xiaobin; Shen, Xiaoming

    2013-01-01

    Sufficient sleep during childhood is essential to ensure a transition into a healthy adulthood. However, chronic sleep loss continues to increase worldwide. In this context, it is imperative to make sleep a high-priority and take action to promote sleep health among children. The present series of studies aimed to shed light on sleep patterns, on the longitudinal association of sleep with school performance, and on practical intervention strategy for Chinese school-aged children. A serial sleep researches, including a national cross-sectional survey, a prospective cohort study, and a school-based sleep intervention, were conducted in China from November 2005 through December 2009. The national cross-sectional survey was conducted in 8 cities and a random sample of 20,778 children aged 9.0±1.61 years participated in the survey. The five-year prospective cohort study included 612 children aged 6.8±0.31 years. The comparative cross-sectional study (baseline: n = 525, aged 10.80±0.41; post-intervention follow-up: n = 553, aged 10.81±0.33) was undertaken in 6 primary schools in Shanghai. A battery of parent and teacher reported questionnaires were used to collect information on children's sleep behaviors, school performance, and sociodemographic characteristics. The mean sleep duration was 9.35±0.77 hours. The prevalence of daytime sleepiness was 64.4% (sometimes: 37.50%; frequently: 26.94%). Daytime sleepiness was significantly associated with impaired attention, learning motivation, and particularly, academic achievement. By contrast, short sleep duration only related to impaired academic achievement. After delaying school start time 30 minutes and 60 minutes, respectively, sleep duration correspondingly increased by 15.6 minutes and 22.8 minutes, respectively. Moreover, intervention significantly improved the sleep duration and daytime sleepiness. Insufficient sleep and daytime sleepiness commonly existed and positively associated with the impairment of

  7. Sleep, school performance, and a school-based intervention among school-aged children: a sleep series study in China.

    Directory of Open Access Journals (Sweden)

    Shenghui Li

    Full Text Available BACKGROUND: Sufficient sleep during childhood is essential to ensure a transition into a healthy adulthood. However, chronic sleep loss continues to increase worldwide. In this context, it is imperative to make sleep a high-priority and take action to promote sleep health among children. The present series of studies aimed to shed light on sleep patterns, on the longitudinal association of sleep with school performance, and on practical intervention strategy for Chinese school-aged children. METHODS AND FINDINGS: A serial sleep researches, including a national cross-sectional survey, a prospective cohort study, and a school-based sleep intervention, were conducted in China from November 2005 through December 2009. The national cross-sectional survey was conducted in 8 cities and a random sample of 20,778 children aged 9.0±1.61 years participated in the survey. The five-year prospective cohort study included 612 children aged 6.8±0.31 years. The comparative cross-sectional study (baseline: n = 525, aged 10.80±0.41; post-intervention follow-up: n = 553, aged 10.81±0.33 was undertaken in 6 primary schools in Shanghai. A battery of parent and teacher reported questionnaires were used to collect information on children's sleep behaviors, school performance, and sociodemographic characteristics. The mean sleep duration was 9.35±0.77 hours. The prevalence of daytime sleepiness was 64.4% (sometimes: 37.50%; frequently: 26.94%. Daytime sleepiness was significantly associated with impaired attention, learning motivation, and particularly, academic achievement. By contrast, short sleep duration only related to impaired academic achievement. After delaying school start time 30 minutes and 60 minutes, respectively, sleep duration correspondingly increased by 15.6 minutes and 22.8 minutes, respectively. Moreover, intervention significantly improved the sleep duration and daytime sleepiness. CONCLUSIONS: Insufficient sleep and daytime sleepiness

  8. A Phase 1 Pharmacokinetic Study of Cysteamine Bitartrate Delayed-Release Capsules Following Oral Administration with Orange Juice, Water, or Omeprazole in Cystinosis.

    Science.gov (United States)

    Armas, Danielle; Holt, Robert J; Confer, Nils F; Checani, Gregg C; Obaidi, Mohammad; Xie, Yuli; Brannagan, Meg

    2018-02-01

    Cystinosis is a rare, metabolic, autosomal recessive, genetic lysosomal storage disorder characterized by an accumulation of cystine in various organs and tissues. Cysteamine bitartrate (CB) is a cystine-depleting aminothiol agent approved in the United States and Europe in immediate-release and delayed-release (DR) formulations for the treatment of nephropathic cystinosis in children and adults. It is recommended that CBDR be administered with fruit juice (except grapefruit juice) for maximum absorption. Omeprazole is a proton pump inhibitor that inhibits gastric acid secretion and, theoretically, may cause the premature release of cysteamine by increasing intragastric pH, thereby affecting the PK of CBDR. This open-label, three-period, randomized study in healthy adult subjects was designed primarily to compare the pharmacokinetics of CBDR capsules after a single oral dose administered with orange juice, water, or multiple oral doses of omeprazole with water at steady state. A total of 32 subjects were randomly assigned to receive study agents in one of two treatment sequences. All subjects completed the study and baseline characteristics of the overall population and the two treatment sequence populations were similar. Peak mean plasma cysteamine concentrations following co-administration of CBDR capsules with orange juice (1892 ng/mL) were higher compared with co-administration with water (1663 ng/mL) or omeprazole 20 mg and water (1712 ng/mL). Mean time to peak plasma concentration was shorter with omeprazole co-administration (2.5 h) compared with orange juice (3.5 h) or water (3.0 h). Statistical comparisons between treatment groups indicated that exposure as assessed by AUC 0-t , AUC 0-∞ , and C max were all within the 80-125% bioequivalence ranges for all comparisons. All treatments were generally well tolerated. Overall, the pharmacokinetics of cysteamine bitartrate DR capsules are not significantly impacted by co-administration with orange juice

  9. School Start Times, Sleep, Behavioral, Health, and Academic Outcomes: A Review of the Literature

    Science.gov (United States)

    Wheaton, Anne G.; Chapman, Daniel P.; Croft, Janet B.

    2016-01-01

    Background: Insufficient sleep in adolescents has been shown to be associated with a wide variety of adverse outcomes, from poor mental and physical health to behavioral problems and lower academic grades. However, most high school students do not get sufficient sleep. Delaying school start times for adolescents has been proposed as a policy…

  10. Dynamics of microbubble oscillators with delay coupling

    Science.gov (United States)

    Heckman, C. R.; Sah, S. M.; Rand, R. H.

    2010-10-01

    We investigate the stability of the in-phase mode in a system of two delay-coupled bubble oscillators. The bubble oscillator model is based on a 1956 paper by Keller and Kolodner. Delay coupling is due to the time it takes for a signal to travel from one bubble to another through the liquid medium that surrounds them. Using techniques from the theory of differential-delay equations as well as perturbation theory, we show that the equilibrium of the in-phase mode can be made unstable if the delay is long enough and if the coupling strength is large enough, resulting in a Hopf bifurcation. We then employ Lindstedt's method to compute the amplitude of the limit cycle as a function of the time delay. This work is motivated by medical applications involving noninvasive localized drug delivery via microbubbles.

  11. Sleep disorders in psychiatry.

    Science.gov (United States)

    Costa e Silva, Jorge Alberto

    2006-10-01

    Sleep is an active state that is critical for our physical, mental, and emotional well-being. Sleep is also important for optimal cognitive functioning, and sleep disruption results in functional impairment. Insomnia is the most common sleep disorder in psychiatry. At any given time, 50% of adults are affected with 1 or more sleep problems such as difficulty in falling or staying asleep, in staying awake, or in adhering to a consistent sleep/wake schedule. Narcolepsy affects as many individuals as does multiple sclerosis or Parkinson disease. Sleep problems are especially prevalent in schizophrenia, depression, and other mental illnesses, and every year, sleep disorders, sleep deprivation, and sleepiness add billions to the national health care bill in industrialized countries. Although psychiatrists often treat patients with insomnia secondary to depression, most patients discuss their insomnia with general care physicians, making it important to provide this group with clear guidelines for the diagnosis and management of insomnia. Once the specific medical, behavioral, or psychiatric causes of the sleep problem have been identified, appropriate treatment can be undertaken. Chronic insomnia has multiple causes arising from medical disorders, psychiatric disorders, primary sleep disorders, circadian rhythm disorders, social or therapeutic use of drugs, or maladaptive behaviors. The emerging concepts of sleep neurophysiology are consistent with the cholinergic-aminergic imbalance hypothesis of mood disorders, which proposes that depression is associated with an increased ratio of central cholinergic to aminergic neurotransmission. The characteristic sleep abnormalities of depression may reflect a relative predominance of cholinergic activity. Antidepressant medications presumably reduce rapid eye movement (REM) sleep either by their anticholinergic properties or by enhancing aminergic neurotransmission. Intense and prolonged dreams often accompany abrupt withdrawal

  12. Quality of Sleep and Related Factors During Chemotherapy in Patients with Stage I/II Breast Cancer

    Directory of Open Access Journals (Sweden)

    Hsiao-Hsuan Kuo

    2006-01-01

    Conclusion: The study showed poor sleep quality and daytime sleepiness in patients with breast cancer during the active phase of chemotherapy. Chemotherapy may bring symptom distress to patients and adversely influence sleep quality.

  13. Group Delay of High Q Antennas

    DEFF Research Database (Denmark)

    Bahramzy, Pevand; Pedersen, Gert Frølund

    2013-01-01

    Group Delay variations versus frequency is an essential factor which can cause distortion and degradation in the signals. Usually this is an issue in wideband communication systems, such as satellite communication systems, which are used for transmitting wideband data. However, group delay can also...... become an issue, when working with high Q antennas, because of the steep phase shift over the frequency. In this paper, it is measured how large group delay variations can become, when going from a low Q antenna to a high Q antenna. The group delay of a low Q antenna is shown to be around 1.3 ns, whereas...... a high Q antenna has group delay of around 22 ns. It is due to this huge group delay variation characteristics of high Q antennas, that signal distortion might occur in the radio system with high Q antennas....

  14. Sleep promotes the extraction of grammatical rules.

    Directory of Open Access Journals (Sweden)

    Ingrid L C Nieuwenhuis

    Full Text Available Grammar acquisition is a high level cognitive function that requires the extraction of complex rules. While it has been proposed that offline time might benefit this type of rule extraction, this remains to be tested. Here, we addressed this question using an artificial grammar learning paradigm. During a short-term memory cover task, eighty-one human participants were exposed to letter sequences generated according to an unknown artificial grammar. Following a time delay of 15 min, 12 h (wake or sleep or 24 h, participants classified novel test sequences as Grammatical or Non-Grammatical. Previous behavioral and functional neuroimaging work has shown that classification can be guided by two distinct underlying processes: (1 the holistic abstraction of the underlying grammar rules and (2 the detection of sequence chunks that appear at varying frequencies during exposure. Here, we show that classification performance improved after sleep. Moreover, this improvement was due to an enhancement of rule abstraction, while the effect of chunk frequency was unaltered by sleep. These findings suggest that sleep plays a critical role in extracting complex structure from separate but related items during integrative memory processing. Our findings stress the importance of alternating periods of learning with sleep in settings in which complex information must be acquired.

  15. Sleep and Metabolism: An Overview

    OpenAIRE

    Sharma, Sunil; Kavuru, Mani

    2010-01-01

    Sleep and its disorders are increasingly becoming important in our sleep deprived society. Sleep is intricately connected to various hormonal and metabolic processes in the body and is important in maintaining metabolic homeostasis. Research shows that sleep deprivation and sleep disorders may have profound metabolic and cardiovascular implications. Sleep deprivation, sleep disordered breathing, and circadian misalignment are believed to cause metabolic dysregulation through myriad pathways i...

  16. Working hours associated with unintentional sleep at work among airline pilots

    Directory of Open Access Journals (Sweden)

    Elaine Cristina Marqueze

    Full Text Available ABSTRACT OBJECTIVE Tto identify factors associated with unintentional sleep at work of airline pilots. METHODS This is a cross-sectional epidemiological study conducted with 1,235 Brazilian airline pilots, who work national or international flights. Data collection has been performed online. We carried out a bivariate and multiple logistic regression analysis, having as dependent variable unintentional sleep at work. The independent variables were related to biodemographic data, characteristics of the work, lifestyle, and aspects of sleep. RESULTS The prevalence of unintentional sleep while flying the airplane was 57.8%. The factors associated with unintentional sleep at work were: flying for more than 65 hours a month, frequent technical delays, greater need for recovery after work, work ability below optimal, insufficient sleep, and excessive sleepiness. CONCLUSIONS The occurrence of unintentional sleep at work of airline pilots is associated with factors related to the organization of the work and health.

  17. Temperature biofeedback and sleep: limited findings and methodological challenges

    Directory of Open Access Journals (Sweden)

    De Koninck J

    2012-10-01

    Full Text Available Geneviève Forest,1,2 Cameron van den Heuvel,3 Kurt Lushington,4 Joseph De Koninck21Sleep Laboratory, Département de Psychoéducation et de Psychologie, Université du Québec en Outaouais, Gatineau, Québec, Canada; 2Sleep and Dreams Laboratory, School of Psychology, University of Ottawa, Ottawa, Ontario, Canada; 3Research Branch University of Adelaide, South Australia, Australia; 4School of Psychology, Social Work and Social Policy, University of South Australia, South Australia, AustraliaAbstract: Given the close link between body temperature and sleep, the perspective of manipulating core and peripheral temperature by self-regulation techniques is very appealing. We report here on a series of attempts conducted independently in two laboratories to use self-regulation (biofeedback of oral (central and hand (peripheral temperature, and measured the impact on sleep-onset latency, sleep architecture, and circadian phase. We found that hand temperature was more successful than oral temperature biofeedback. Moreover, an increase in hand temperature was associated with reduced sleep-onset latency. However, most participants found the procedure difficult to implement. The temperature response to biofeedback was reduced in the aged and weakest at the time of sleep onset, and there was not a systematic relationship between the change in temperature and change in sleep latency. Methodological limitations and individual differences may account for these results. Recommendations for future research are presented.Keywords: biofeedback, core body temperature, sleep, circadian rhythm, sleep onset

  18. Sleep and Athletic Performance.

    Science.gov (United States)

    Watson, Andrew M

    Sleep is an essential component of health and well-being, with significant impacts on physical development, emotional regulation, cognitive performance, and quality of life. Along with being an integral part of the recovery and adaptive process between bouts of exercise, accumulating evidence suggests that increased sleep duration and improved sleep quality in athletes are associated with improved performance and competitive success. In addition, better sleep may reduce the risk of both injury and illness in athletes, not only optimizing health but also potentially enhancing performance through increased participation in training. Despite this, most studies have found that athletes fail to obtain the recommended amount of sleep, threatening both performance and health. Athletes face a number of obstacles that can reduce the likelihood of obtaining proper sleep, such as training and competition schedules, travel, stress, academic demands, and overtraining. In addition, athletes have been found to demonstrate poor self-assessment of their sleep duration and quality. In light of this, athletes may require more careful monitoring and intervention to identify individuals at risk and promote proper sleep to improve both performance and overall health. This review attempts to highlight the recent literature regarding sleep issues in athletes, the effects of sleep on athletic performance, and interventions to enhance proper sleep in athletes.

  19. Sleep and Salivary Cortisol

    DEFF Research Database (Denmark)

    Garde, Anne Helene; Karlson, Bernt; Hansen, Åse Marie

    2011-01-01

    The aim of the present chapter was to analyze whether measures of cortisol in saliva were associated with measures of sleep and to explore if divergent results were related to underlying differences in theoretic assumptions and methods. Measures of sleep quality included sleep duration, overall...... sleep quality, difficulty falling asleep, disturbed sleep, and sleep deprivation. Twenty-three papers were found to fulfill the inclusion criteria. Cortisol measures were grouped into single time points at different times during the day, deviations at different time periods during the day, reactivity...... and recovery after a standardized laboratory test, area under the curve and response to dexamethasone test. A large proportion of the studies included showed non-significant findings, which, in several cases, may be a result of low power. The most consistent results were a positive association between sleep...

  20. Sleep and psychiatry

    Science.gov (United States)

    Abad, Vivien C.; Guilleminault, Christian

    2005-01-01

    Psychiatric disorders constitute 15.4% of the disease burden in established market economies. Many psychiatric disorders are associated with sleep disturbances, and the relationship is often bidirectional. This paper reviews the prevalence of various psychiatric disorders, their clinical presentation, and their association with sleep disorders. Among the psychiatric disorders reviewed are affective disorders, psychosis, anxiety disorders (including post-traumatic stress disorder), substance abuse disorders, eating disorders, and attention deficit/hyperactivity disorders. The spectrum of associated sleep disorders includes insomnia, hypersomnia, nocturnal panic, sleep paralysis, hypnagogic hallucinations, restless legs/periodic limb movements of sleep, obstructive sleep apnea, and parasomnias. The effects on sleep of various psychotropic medications utilized to treat the above psychiatric disorders are summarized. PMID:16416705

  1. Sleep and Sleep Problems: From Birth to 3

    Science.gov (United States)

    Du Mond, Courtney; Mindell, Jodi A.

    2011-01-01

    Sleep is an important aspect of a child's early development and is essential to family well-being. During their first 3 years, infants and toddlers spend more than 50% of their lives sleeping. However, concerns about sleep and sleep problems are among the most common issues brought to the attention of pediatricians. Although sleep is one of the…

  2. A global quantification of “normal” sleep schedules using smartphone data

    Science.gov (United States)

    Walch, Olivia J.; Cochran, Amy; Forger, Daniel B.

    2016-01-01

    The influence of the circadian clock on sleep scheduling has been studied extensively in the laboratory; however, the effects of society on sleep remain largely unquantified. We show how a smartphone app that we have developed, ENTRAIN, accurately collects data on sleep habits around the world. Through mathematical modeling and statistics, we find that social pressures weaken and/or conceal biological drives in the evening, leading individuals to delay their bedtime and shorten their sleep. A country’s average bedtime, but not average wake time, predicts sleep duration. We further show that mathematical models based on controlled laboratory experiments predict qualitative trends in sunrise, sunset, and light level; however, these effects are attenuated in the real world around bedtime. Additionally, we find that women schedule more sleep than men and that users reporting that they are typically exposed to outdoor light go to sleep earlier and sleep more than those reporting indoor light. Finally, we find that age is the primary determinant of sleep timing, and that age plays an important role in the variability of population-level sleep habits. This work better defines and personalizes “normal” sleep, produces hypotheses for future testing in the laboratory, and suggests important ways to counteract the global sleep crisis. PMID:27386531

  3. Later school start time is associated with improved sleep and daytime functioning in adolescents.

    Science.gov (United States)

    Boergers, Julie; Gable, Christopher J; Owens, Judith A

    2014-01-01

    Chronic insufficient sleep is a growing concern among adolescents and is associated with a host of adverse health consequences. Early school start times may be an environmental contributor to this problem. The purpose of this study was to examine the impact of a delay in school start time on sleep patterns, sleepiness, mood, and health-related outcomes. Boarding students (n = 197, mean age = 15.6 yr) attending an independent high school completed the School Sleep Habits Survey before and after the school start time was experimentally delayed from 8:00 a.m. to 8:25 a.m. The delay in school start time was associated with a significant (29 min) increase in sleep duration on school nights. The percentage of students receiving 8 or more hours of sleep on a school night increased to more than double, from 18% to 44%. Students in 9th and 10th grade and those with lower baseline sleep amounts were more likely to report improvements in sleep duration after the schedule change. Daytime sleepiness, depressed mood, and caffeine use were all significantly reduced after the delay in school start time. Sleep duration reverted to baseline levels when the original (earlier) school start time was reinstituted. A modest (25 min) delay in school start time was associated with significant improvements in sleep duration, daytime sleepiness, mood, and caffeine use. These findings have important implications for public policy and add to research suggesting the health benefits of modifying school schedules to more closely align with adolescents' circadian rhythms and sleep needs.

  4. Primary sleep disorders can cause long-term sleep disturbance in patients with autoimmune mediated limbic encephalitis.

    Science.gov (United States)

    Anderson, Kirstie N; Kelly, Thomas P; Griffiths, Timothy D

    2013-07-01

    Antibody mediated limbic encephalitis causes a sub acute encephalopathy with an amnestic syndrome, seizures and often an affective prodrome. Sleep disturbance including abnormal dream sleep and insomnia are described in a percentage of long-term survivors but there are very few detailed assessments of sleep disturbance in patients beyond the acute phase of illness. The objectives of this study were to understand the causes of sleep disturbance in the long-term survivors of antibody mediated limbic encephalitis. We screened twelve patients under long-term follow up with sleep questionnaires and went on to perform detailed sleep studies (polysomnography) in those who reported sleep disturbance. Two were found to have persistent, severe central and obstructive sleep apnoea and two others to have restless legs and periodic limb movements of sleep. This highlights the need to investigate sleep disturbance in this group of patients. Effective treatments may be available to improve quality of life and daytime function. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Word encoding during sleep is suggested by correlations between word-evoked up-states and post-sleep semantic priming

    Directory of Open Access Journals (Sweden)

    Simon eRuch

    2014-11-01

    Full Text Available To test whether humans can encode words during sleep we played everyday words to men while they were napping and assessed priming from sleep-played words following waking. Words were presented during non-rapid eye movement (NREM sleep. Priming was assessed using a semantic and a perceptual priming test. These tests measured differences in the processing of words that had been or had not been played during sleep. Synonyms to sleep-played words were the targets in the semantic priming test that tapped the meaning of sleep-played words. All men responded to sleep-played words by producing up-states in their electroencephalogram. Up-states are NREM sleep-specific phases of briefly increased neuronal excitability. The word-evoked up-states might have promoted word processing during sleep. Yet, the mean performance in the priming tests administered following sleep was at chance level, which suggests that participants as a group failed to show priming following sleep. However, performance in the two priming tests was positively correlated to each other and to the magnitude of the word-evoked up-states. Hence, the larger a participant’s word-evoked up-states, the larger his perceptual and semantic priming. Those participants who scored high on all variables must have encoded words during sleep. We conclude that some humans are able to encode words during sleep, but more research is needed to pin down the factors that modulate this ability.

  6. Context odor presentation during sleep enhances memory in honeybees.

    Science.gov (United States)

    Zwaka, Hanna; Bartels, Ruth; Gora, Jacob; Franck, Vivien; Culo, Ana; Götsch, Moritz; Menzel, Randolf

    2015-11-02

    Sleep plays an important role in stabilizing new memory traces after learning [1-3]. Here we investigate whether sleep's role in memory processing is similar in evolutionarily distant species and demonstrate that a context trigger during deep-sleep phases improves memory in invertebrates, as it does in humans. We show that in honeybees (Apis mellifera), exposure to an odor during deep sleep that has been present during learning improves memory performance the following day. Presentation of the context odor during wake phases or novel odors during sleep does not enhance memory. In humans, memory consolidation can be triggered by presentation of a context odor during slow-wave sleep that had been present during learning [3-5]. Our results reveal that deep-sleep phases in honeybees have the potential to prompt memory consolidation, just as they do in humans. This study provides strong evidence for a conserved role of sleep-and how it affects memory processes-from insects to mammals. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. The inappropriate occurrence of rapid eye movement sleep in narcolepsy is not due to a defect in homeostatic regulation of rapid eye movement sleep.

    Science.gov (United States)

    Roman, Alexis; Meftah, Soraya; Arthaud, Sébastien; Luppi, Pierre-Hervé; Peyron, Christelle

    2018-06-01

    Narcolepsy type 1 is a disabling disorder with four primary symptoms: excessive-daytime-sleepiness, cataplexy, hypnagogic hallucinations, and sleep paralysis. The later three symptoms together with a short rapid eye movement (REM) sleep latency have suggested impairment in REM sleep homeostatic regulation with an enhanced propensity for (i.e. tendency to enter) REM sleep. To test this hypothesis, we challenged REM sleep homeostatic regulation in a recognized model of narcolepsy, the orexin knock-out (Orex-KO) mice and their wild-type (WT) littermates. We first performed 48 hr of REM sleep deprivation using the classic small-platforms-over-water method. We found that narcoleptic mice are similarly REM sleep deprived to WT mice. Although they had shorter sleep latency, Orex-KO mice recovered similarly to WT during the following 10 hr of recovery. Interestingly, Orex-KO mice also had cataplexy episodes immediately after REM sleep deprivation, anticipating REM sleep rebound, at a time of day when cataplexy does not occur in baseline condition. We then evaluated REM sleep propensity using our new automated method of deprivation that performs a specific and efficient REM sleep deprivation. We showed that REM sleep propensity is similar during light phase in Orex-KO and WT mice. However, during the dark phase, REM sleep propensity was not suppressed in Orex-KO mice when hypocretin/orexin neuropeptides are normally released. Altogether our data suggest that in addition to the well-known wake-promoting role of hypocretin/orexin, these neuropeptides would also suppress REM sleep. Therefore, hypocretin/orexin deficiency would facilitate the occurrence of REM sleep at any time of day in an opportunistic manner as seen in human narcolepsy.

  8. UAVs and Control Delays

    National Research Council Canada - National Science Library

    de Vries, S. C

    2005-01-01

    .... Delays of about 250-300 ms often lead to unacceptable airplane handling qualities. Techniques such as filtering and predictive displays may extend the range of acceptable delays up to about 400 ms...

  9. Delayed puberty in boys

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/007695.htm Delayed puberty in boys To use the sharing features on this page, please enable JavaScript. Delayed puberty in boys is when puberty does not begin ...

  10. Sleep-wake and melatonin pattern in craniopharyngioma patients.

    Science.gov (United States)

    Pickering, Line; Jennum, Poul; Gammeltoft, Steen; Poulsgaard, Lars; Feldt-Rasmussen, Ulla; Klose, Marianne

    2014-06-01

    To assess the influence of craniopharyngioma or consequent surgery on melatonin secretion, and the association with fatigue, sleepiness, sleep pattern and sleep quality. Cross-sectional study. A total of 15 craniopharyngioma patients were individually matched to healthy controls. In this study, 24-h salivary melatonin and cortisol were measured. Sleep-wake patterns were characterised by actigraphy and sleep diaries recorded for 2 weeks. Sleepiness, fatigue, sleep quality and general health were assessed by Multidimensional Fatigue Inventory, Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale and Short-Form 36. Patients had increased mental fatigue, daytime dysfunction, sleep latency and lower general health (all, P≤0.05), and they tended to have increased daytime sleepiness, general fatigue and impaired sleep quality compared with controls. The degree of hypothalamic injury was associated with an increased BMI and lower mental health (P=0.01). High BMI was associated with increased daytime sleepiness, daytime dysfunction, mental fatigue and lower mental health (all, P≤0.01). Low midnight melatonin was associated with reduced sleep time and efficiency (P≤0.03) and a tendency for increased sleepiness, impaired sleep quality and physical health. Midnight melatonin remained independently related to sleep time after adjustment for cortisol. Three different patterns of melatonin profiles were observed; normal (n=6), absent midnight peak (n=6) and phase-shifted peak (n=2). Only patients with absent midnight peak had impaired sleep quality, increased daytime sleepiness and general and mental fatigue. Craniopharyngioma patients present with changes in circadian pattern and daytime symptoms, which may be due to the influence of the craniopharyngioma or its treatment on the hypothalamic circadian and sleep regulatory nuclei. © 2014 European Society of Endocrinology.

  11. [Aspects of sleep effects on the digestive tract].

    Science.gov (United States)

    Dantas, Roberto Oliveira; Aben-Athar, Cynthia Gutierrez

    2002-01-01

    During sleep the gastrointestinal system function is markedly reduced most of the time. In this revision we described the effect of sleep on the digestive system. Salivation, swallowing rate, upper esophageal sphincter pressure and number of primary esophageal contractions have all been shown to be reduced during sleep. Gastric emptying is slow during sleep but the REM sleep is associated with faster gastric emptying. During the night we have a more regular intestinal motility than during the day. During sleep, phase II of the migrating motor complex cycle is virtually absent, both during diurnal or nocturnal sleep. The nocturnal velocity of migrating motor complex propagation in the proximal small bowel is slower than the diurnal velocity. The colon has a decrease in tonus and contractions. The anal canal pressure is lower and rectum activity is higher during sleep than during the awake state, but the anal pressure is still higher than the rectum pressure and the rectum contractions are most frequently retrograde. Transient lower esophageal sphincter relaxation is the most frequent cause of gastroesophageal reflux. The frequency of this transient relaxation is very low during sleep. Gastroesophageal reflux during sleep is more frequently associated with a low lower esophageal sphincter pressure. In this situation the disease is worse because the patient is in the supine position, so gravity does not help the acid esophageal clearance, salivation is decreased and the primary esophageal contraction is not frequent, a fact causing a prolongation of acid clearance during sleep. The right lateral position during sleep causes more reflux episodes than the left lateral position. The gastroesophageal reflux may be associated with nocturnal wheezing, chronic nocturnal cough and sleep apnea.

  12. Parasite resistance and the adaptive significance of sleep

    Directory of Open Access Journals (Sweden)

    Barton Robert A

    2009-01-01

    Full Text Available Abstract Background Sleep is a biological enigma. Despite occupying much of an animal's life, and having been scrutinized by numerous experimental studies, there is still no consensus on its function. Similarly, no hypothesis has yet explained why species have evolved such marked variation in their sleep requirements (from 3 to 20 hours a day in mammals. One intriguing but untested idea is that sleep has evolved by playing an important role in protecting animals from parasitic infection. This theory stems, in part, from clinical observations of intimate physiological links between sleep and the immune system. Here, we test this hypothesis by conducting comparative analyses of mammalian sleep, immune system parameters, and parasitism. Results We found that evolutionary increases in mammalian sleep durations are strongly associated with an enhancement of immune defences as measured by the number of immune cells circulating in peripheral blood. This appeared to be a generalized relationship that could be independently detected in 4 of the 5 immune cell types and in both of the main sleep phases. Importantly, no comparable relationships occur in related physiological systems that do not serve an immune function. Consistent with an influence of sleep on immune investment, mammalian species that sleep for longer periods also had substantially reduced levels of parasitic infection. Conclusion These relationships suggest that parasite resistance has played an important role in the evolution of mammalian sleep. Species that have evolved longer sleep durations appear to be able to increase investment in their immune systems and be better protected from parasites. These results are neither predicted nor explained by conventional theories of sleep evolution, and suggest that sleep has a much wider role in disease resistance than is currently appreciated.

  13. Sleep from an Islamic perspective.

    Science.gov (United States)

    Bahammam, Ahmed S

    2011-10-01

    Sleep medicine is a relatively new scientific specialty. Sleep is an important topic in Islamic literature, and the Quran and Hadith discuss types of sleep, the importance of sleep, and good sleep practices. Islam considers sleep as one of the signs of the greatness of Allνh (God) and encourages followers to explore this important sign. The Quran describes different types of sleep, and these correspond with sleep stages identified by modern science. The Quran discusses the beneficial effects of sleep and emphasizes the importance of maintaining a pattern of light and darkness. A mid-day nap is an important practice for Muslims, and the Prophet Muhammad peace be upon him (pbuh) promoted naps as beneficial. In accordance with the practice and instructions of Muhammad (pbuh), Muslims have certain sleep habits and these sleep habits correspond to some of the sleep hygiene rules identified by modern science. Details during sleep include sleep position, like encouraging sleep on the right side and discouraging sleep in the prone position. Dream interpretation is an established science in the Islamic literature and Islamic scholars have made significant contributions to theories of dream interpretation. We suggest that sleep scientists examine religious literature in general and Islamic literature in particular, to understand the views, behaviors, and practices of ancient people about the sleep and sleep disorders. Such studies may help to answer some unresolved questions in sleep science or lead to new areas of inquiry.

  14. Chronic sleep reduction in adolescents

    NARCIS (Netherlands)

    Dewald-Kaufmann, J.F.

    2012-01-01

    Based on the results of this thesis, it can be concluded that sleep problems and chronic sleep reduction have a high impact on adolescents’ daytime functioning. Additionally, this research shows that gradual sleep extension can improve adolescents’ sleep and especially their chronic sleep reduction.

  15. Sleep from an islamic perspective

    Directory of Open Access Journals (Sweden)

    Ahmed S BaHammam

    2011-01-01

    Full Text Available Sleep medicine is a relatively new scientific specialty. Sleep is an important topic in Islamic literature, and the Quran and Hadith discuss types of sleep, the importance of sleep, and good sleep practices. Islam considers sleep as one of the signs of the greatness of Allβh (God and encourages followers to explore this important sign. The Quran describes different types of sleep, and these correspond with sleep stages identified by modern science. The Quran discusses the beneficial effects of sleep and emphasizes the importance of maintaining a pattern of light and darkness. A mid-day nap is an important practice for Muslims, and the Prophet Muhammad peace be upon him (pbuh promoted naps as beneficial. In accordance with the practice and instructions of Muhammad (pbuh, Muslims have certain sleep habits and these sleep habits correspond to some of the sleep hygiene rules identified by modern science. Details during sleep include sleep position, like encouraging sleep on the right side and discouraging sleep in the prone position. Dream interpretation is an established science in the Islamic literature and Islamic scholars have made significant contributions to theories of dream interpretation. We suggest that sleep scientists examine religious literature in general and Islamic literature in particular, to understand the views, behaviors, and practices of ancient people about the sleep and sleep disorders. Such studies may help to answer some unresolved questions in sleep science or lead to new areas of inquiry.

  16. Genetic Dissociation of Daily Sleep and Sleep Following Thermogenetic Sleep Deprivation in Drosophila.

    Science.gov (United States)

    Dubowy, Christine; Moravcevic, Katarina; Yue, Zhifeng; Wan, Joy Y; Van Dongen, Hans P A; Sehgal, Amita

    2016-05-01

    Sleep rebound-the increase in sleep that follows sleep deprivation-is a hallmark of homeostatic sleep regulation that is conserved across the animal kingdom. However, both the mechanisms that underlie sleep rebound and its relationship to habitual daily sleep remain unclear. To address this, we developed an efficient thermogenetic method of inducing sleep deprivation in Drosophila that produces a substantial rebound, and applied the newly developed method to assess sleep rebound in a screen of 1,741 mutated lines. We used data generated by this screen to identify lines with reduced sleep rebound following thermogenetic sleep deprivation, and to probe the relationship between habitual sleep amount and sleep following thermogenetic sleep deprivation in Drosophila. To develop a thermogenetic method of sleep deprivation suitable for screening, we thermogenetically stimulated different populations of wake-promoting neurons labeled by Gal4 drivers. Sleep rebound following thermogenetically-induced wakefulness varies across the different sets of wake-promoting neurons that were stimulated, from very little to quite substantial. Thermogenetic activation of neurons marked by the c584-Gal4 driver produces both strong sleep loss and a substantial rebound that is more consistent within genotypes than rebound following mechanical or caffeine-induced sleep deprivation. We therefore used this driver to induce sleep deprivation in a screen of 1,741 mutagenized lines generated by the Drosophila Gene Disruption Project. Flies were subjected to 9 h of sleep deprivation during the dark period and released from sleep deprivation 3 h before lights-on. Recovery was measured over the 15 h following sleep deprivation. Following identification of lines with reduced sleep rebound, we characterized baseline sleep and sleep depth before and after sleep deprivation for these hits. We identified two lines that consistently exhibit a blunted increase in the duration and depth of sleep after

  17. Delayed Orgasm and Anorgasmia

    OpenAIRE

    Jenkins, Lawrence C.; Mulhall, John P.

    2015-01-01

    Delayed orgasm/anorgasmia defined as the persistent or recurrent difficulty, delay in, or absence of attaining orgasm after sufficient sexual stimulation, which causes personal distress. Delayed orgasm and anorgasmia are associated with significant sexual dissatisfaction. A focused medical history can shed light on the potential etiologies; which include: medications, penile sensation loss, endocrinopathies, penile hyperstimulation and psychological etiologies, amongst others. Unfortunately, ...

  18. A Phase II single-arm trial of palonosetron for the prevention of acute and delayed chemotherapy-induced nausea and vomiting in malignant glioma patients receiving multidose irinotecan in combination with bevacizumab

    Directory of Open Access Journals (Sweden)

    Affronti ML

    2016-12-01

    Full Text Available Mary Lou Affronti,1–3 Sarah Woodring,1,2 Katherine B Peters,1,4 James E Herndon II,5 Frances McSherry,5 Patrick N Healy,5 Annick Desjardins,1,4 James J Vredenburgh,6 Henry S Friedman1,2 1The Preston Robert Tisch Brain Tumor Center at Duke, South Hospital, Duke University Medical Center, 2Department of Neurosurgery, Duke University Health System, 3Duke University School of Nursing, 4Department of Neurology, 5Department of Biostatistics and Bioinformatics, Duke University Health System, Durham, NC, 6Saint Francis Cancer Center, Hartford, CT, USA Purpose: Given that the prognosis of recurrent malignant glioma (MG remains poor, improving quality of life (QoL through symptom management is important. Meta-analyses establishing antiemetic guidelines have demonstrated the superiority of palonosetron (PAL over older 5-hydroxytryptamine 3-receptor antagonists in chemotherapy-induced nausea and vomiting (CINV prevention, but excluded patients with gliomas. Irinotecan plus bevacizumab is a treatment frequently used in MG, but is associated with low (55% CINV complete response (CR; no emesis or use of rescue antiemetic with commonly prescribed ondansetron. A single-arm Phase II trial was conducted in MG patients to determine the efficacy of intravenous PAL (0.25 mg and dexamethasone (DEX; 10 mg received in conjunction with biweekly irinotecan–bevacizumab treatment. The primary end point was the proportion of subjects achieving acute CINV CR (no emesis or antiemetic ≤24 hours postchemotherapy. Secondary end points included delayed CINV CR (days 2–5, overall CINV CR (days 1–5, and QoL, fatigue, and toxicity.Materials and methods: A two-stage design of 160 patients was planned to differentiate between CINV CR of 55% and 65% after each dose of PAL–DEX. Validated surveys assessed fatigue and QoL.Results: A total of 63 patients were enrolled, after which enrollment was terminated due to slow accrual; 52 patients were evaluable for the primary outcome

  19. The circadian regulation of sleep: impact of a functional ADA-polymorphism and its association to working memory improvements.

    Directory of Open Access Journals (Sweden)

    Carolin F Reichert

    Full Text Available Sleep is regulated in a time-of-day dependent manner and profits working memory. However, the impact of the circadian timing system as well as contributions of specific sleep properties to this beneficial effect remains largely unexplored. Moreover, it is unclear to which extent inter-individual differences in sleep-wake regulation depend on circadian phase and modulate the association between sleep and working memory. Here, sleep electroencephalography (EEG was recorded during a 40-h multiple nap protocol, and working memory performance was assessed by the n-back task 10 times before and after each scheduled nap sleep episode. Twenty-four participants were genotyped regarding a functional polymorphism in adenosine deaminase (rs73598374, 12 G/A-, 12 G/G-allele carriers, previously associated with differences in sleep-wake regulation. Our results indicate that genotype-driven differences in sleep depend on circadian phase: heterozygous participants were awake longer and slept less at the end of the biological day, while they exhibited longer non rapid eye movement (NREM sleep and slow wave sleep concomitant with reduced power between 8-16 Hz at the end of the biological night. Slow wave sleep and NREM sleep delta EEG activity covaried positively with overall working memory performance, independent of circadian phase and genotype. Moreover, REM sleep duration benefitted working memory particularly when occurring in the early morning hours and specifically in heterozygous individuals. Even though based on a small sample size and thus requiring replication, our results suggest genotype-dependent differences in circadian sleep regulation. They further indicate that REM sleep, being under strong circadian control, boosts working memory performance according to genotype in a time-of-day dependent manner. Finally, our data provide first evidence that slow wave sleep and NREM sleep delta activity, majorly regulated by sleep homeostatic mechanisms, is

  20. The effects of sleep extension on sleep and cognitive performance in adolescents with chronic sleep reduction: an experimental study

    NARCIS (Netherlands)

    Dewald-Kaufmann, J.F.; Oort, F.J.; Meijer, A.M.

    2013-01-01

    Objective: To investigate the effects of gradual sleep extension in adolescents with chronic sleep reduction. Outcome variables were objectively measured sleep and cognitive performance. Methods: Participants were randomly assigned to either a sleep extension group (gradual sleep extension by

  1. Dual-phase 99mTc-MIBI scintigraphy with delayed neck and thorax SPECT/CT and bone scintigraphy in patients with primary hyperparathyroidism. Correlation with clinical or pathological variables

    International Nuclear Information System (INIS)

    Qiu, Zhongling; Shen, Chentian; Zhu, Ruisen; Luo, Quanyong; Wu, Bo

    2014-01-01

    The purpose of this study was to assess the relationship between 99m Tc-MIBI and 99m Tc-MDP bone scintigraphy and clinical or pathological variables, including preoperative serum PTH levels and tumor diameter, in patients with newly diagnosed PHPT. Dual phase 99m Tc-MIBI planar scintigraphy was performed in 244 patients with PHPT. Of these patients, 155 underwent 99m Tc-MDP bone scintigraphy to detect bone changes before parathyroidectomy. Factors influencing 99m Tc-MIBI scintigraphy and 99m Tc-MDP bone scintigraphy detection rate were assessed using univariate and multivariate logistic regression analysis; optimal cutoff values for predicting positive 99m Tc-MIBI and 99m Tc-MDP bone scintigraphy were evaluated using ROC analysis. Among 244 patients, 174 (71.31%) patients with 181 foci had a positive 99m Tc-MIBI planar scintigraphy; delayed neck and thorax SPECT/CT could identify and locate the 99m Tc-MIBI lesions but could not find more lesions than planar scintigraphy. 70 (28.69%) patients had a negative 99m Tc-MIBI planar scintigraphy. Tumor diameter, serum PTH level and symptoms were statistically significant predictive factors in predicting positive 9m Tc-MIBI scintigraphy both univariate and multivariate logistic regression analyses. The optimal thresholds for tumor diameter and serum PTH by ROC analysis were 1.03 cm and 127.60 ng/L, respectively. Among 155 patients with bone scintigraphy, 99m Tc-MDP bone scintigraphy showed positive finding in 80 (51.61%) patients and negative finding in 75 patients. Univariate logistic regression analysis showed that patient age, sex, tumor diameter and PTH level (≥150 ng/L) were statistically significant in predicting positive 99m Tc-MDP bone scintigraphy. Multivariate logistic regression analysis showed both tumor diameter and PTH ≥150 ng/L were statistically significant in predicting positive 99m Tc-MDP bone scintigraphy. The optimal thresholds for tumor diameter and serum PTH by ROC analysis were 1.96 cm and 163

  2. Sleep bruxism and sleep-disordered breathing: a systematic review.

    Science.gov (United States)

    De Luca Canto, Graziela; Singh, Vandana; Gozal, David; Major, Paul W; Flores-Mir, Carlos

    2014-01-01

    To carry out a systematic review to consolidate current knowledge on the potential association between sleep bruxism (SB) and sleep-disordered breathing (SDB). For this systematic review, articles were retained only if they reported studies using full ambulatory polysomnography as "the gold standard" reference test to determine SDB and the international diagnostic criteria proposed by the American Association of Sleep Medicine to determine SB. Detailed individual search strategies from MEDLINE, PubMed, Embase, the Cochrane Library, and LILACS databases were developed. The references cited in the selected articles were also checked, and a partial literature search was undertaken. The selection was completed independently by two reviewers in two phases. The methodology of selected studies was evaluated using the seven-item quality-assessment tool for experimental bruxism studies. During the initial search, 333 different citations were identified across the six electronic databases. After a comprehensive evaluation of the abstracts, and the full papers when considered necessary, only one study was finally selected for the qualitative/quantitative synthesis. This study did not support the putative association between SB and SDB, since SB was not observed during or in temporal conjunction with snoring or apneic events in any of the evaluated patients. In addition, masseter activity was not observed during apneic episodes. There is not sufficient scientific evidence either to confirm or discredit the association between SB and SDB.

  3. The Relations Between Sleep, Personality, Behavioral Problems, and School Performance in Adolescents.

    Science.gov (United States)

    Schmidt, Ralph E; Van der Linden, Martial

    2015-06-01

    According to recent meta-analyses, adolescents across different countries and cultures do not get the recommended amount of sleep. Extracurricular activities, part-time jobs, and use of electronic devices in the evening delay bedtime in adolescents. Early school start times also shorten the time for sleep. Insufficient sleep in adolescents has been associated with weakened emotional-behavioral regulation and poor academic achievement. Multicomponent intervention programs have been developed on the basis of cognitive-behavioral therapy for insomnia to improve sleep in youth. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Common Sleep Problems (For Teens)

    Science.gov (United States)

    ... Safe Videos for Educators Search English Español Common Sleep Problems KidsHealth / For Teens / Common Sleep Problems What's ... have emotional problems, like depression. What Happens During Sleep? You don't notice it, of course, but ...

  5. Sleep disorders in the elderly

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/000064.htm Sleep disorders in older adults To use the sharing features on this page, please enable JavaScript. Sleep disorders in older adults involve any disrupted sleep ...

  6. Healthy People 2020: Sleep Health

    Science.gov (United States)

    ... improve health, productivity, wellness, quality of life, and safety on roads and in the workplace. Overview Poor sleep health ... adopt strategies that reduce risks to health and safety. Without sleep health education, individuals often prioritize other activities over sleep and ...

  7. [Sleep disorders and epilepsy].

    Science.gov (United States)

    Aoki, Ryo; Ito, Hiroshi

    2014-05-01

    It has been reported that patients with epilepsy often have insomnia and/or daytime sleepiness; the symptomatologic features differ in seizure types. Not only the administration of anti-epileptics, but also inappropriate sleep hygiene cause daytime sleepiness. In subjective assessment of sleepiness, we need to pay attention if it can correctly assess or not. The prevalence of obstructive sleep apnea in patients with epilepsy is approximately 10-30%. Sleep apnea deteriorates the seizure control because of worsen sleep condition by sleep apnea, especially in elderly patients. Some researchers report that continuous positive airway pressure was effective for seizure control. Patients with epilepsy occasionally have REM sleep behavior disorder as comorbidity. Examination using polysomnography is required for differential diagnosis.

  8. The perception of sleep quality in kidney transplant patients during the first year of transplantation

    Directory of Open Access Journals (Sweden)

    Dnyelle Souza Silva

    2012-12-01

    Full Text Available OBJECTIVE: Poor sleep quality is one of the factors that adversely affects patient quality of life after kidney transplantation, and sleep disorders represent a significant cardiovascular risk factor. The objective of this study was to investigate the prevalence of changes in sleep quality and their outcomes in kidney transplant recipients and analyze the variables affecting sleep quality in the first years after renal transplantation. METHODS: Kidney transplant recipients were evaluated at two time points after a successful transplantation: between three and six months (Phase 1 and between 12 and 15 months (Phase 2. The following tools were used for assessment: the Pittsburgh Sleep Quality Index; the quality of life questionnaire Short-Form-36; the Hospital Anxiety and Depression scale; the Karnofsky scale; and assessments of social and demographic data. The prevalence of poor sleep was 36.7% in Phase 1 and 38.3% in Phase 2 of the study. RESULTS: There were no significant differences between patients with and without changes in sleep quality between the two phases. We found no changes in sleep patterns throughout the study. Both the physical and mental health scores worsened from Phase 1 to Phase 2. CONCLUSION: Sleep quality in kidney transplant recipients did not change during the first year after a successful renal transplantation.

  9. NREM sleep hypersomnia and reduced sleep/wake continuity in a neuroendocrine mouse model of anxiety/depression based on chronic corticosterone administration.

    Science.gov (United States)

    Le Dantec, Y; Hache, G; Guilloux, J P; Guiard, B P; David, D J; Adrien, J; Escourrou, P

    2014-08-22

    Sleep/wake disorders are frequently associated with anxiety and depression and to elevated levels of cortisol. Even though these alterations are increasingly sought in animal models, no study has investigated the specific effects of chronic corticosterone (CORT) administration on sleep. We characterized sleep/wake disorders in a neuroendocrine mouse model of anxiety/depression, based on chronic CORT administration in the drinking water (35 μg/ml for 4 weeks, "CORT model"). The CORT model was markedly affected during the dark phase by non-rapid eye movement sleep (NREM) increase without consistent alteration of rapid eye movement (REM) sleep. Total sleep duration (SD) and sleep efficiency (SE) increased concomitantly during both the 24h and the dark phase, due to the increase in the number of NREM sleep episodes without a change in their mean duration. Conversely, the total duration of wake decreased due to a decrease in the mean duration of wake episodes despite an increase in their number. These results reflect hypersomnia by intrusion of NREM sleep during the active period as well as a decrease in sleep/wake continuity. In addition, NREM sleep was lighter, with an increased electroencephalogram (EEG) theta activity. With regard to REM sleep, the number and the duration of episodes decreased, specifically during the first part of the light period. REM and NREM sleep changes correlated respectively with the anxiety and the anxiety/depressive-like phenotypes, supporting the notion that studying sleep could be of predictive value for altered emotional behavior. The chronic CORT model in mice that displays hallmark characteristics of anxiety and depression provides an insight into understanding the changes in overall sleep architecture that occur under pathological conditions. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

  10. Cued Memory Reactivation During SWS Abolishes the Beneficial Effect of Sleep on Abstraction.

    Science.gov (United States)

    Hennies, Nora; Lambon Ralph, Matthew A; Durrant, Simon J; Cousins, James N; Lewis, Penelope A

    2017-08-01

    Extracting regularities from stimuli in our environment and generalizing these to new situations are fundamental processes in human cognition. Sleep has been shown to enhance these processes, possibly by facilitating reactivation-triggered memory reorganization. Here, we assessed whether cued reactivation during slow wave sleep (SWS) promotes the beneficial effect of sleep on abstraction of statistical regularities. We used an auditory statistical learning task, in which the benefit of sleep has been firmly established. Participants were exposed to a probabilistically determined sequence of tones and subsequently tested for recognition of novel short sequences adhering to this same statistical pattern in both immediate and delayed recall sessions. In different groups, the exposure stream was replayed during SWS in the night between the recall sessions (SWS-replay group), in wake just before sleep (presleep replay group), or not at all (control group). Surprisingly, participants who received replay in sleep performed worse in the delayed recall session than the control and the presleep replay group. They also failed to show the association between SWS and task performance that has been observed in previous studies and was present in the controls. Importantly, sleep structure and sleep quality did not differ between groups, suggesting that replay during SWS did not impair sleep but rather disrupted or interfered with sleep-dependent mechanisms that underlie the extraction of the statistical pattern. These findings raise important questions about the scope of cued memory reactivation and the mechanisms that underlie sleep-related generalization. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

  11. Declarative memory performance is associated with the number of sleep spindles in elderly women.

    Science.gov (United States)

    Seeck-Hirschner, Mareen; Baier, Paul Christian; Weinhold, Sara Lena; Dittmar, Manuela; Heiermann, Steffanie; Aldenhoff, Josef B; Göder, Robert

    2012-09-01

    Recent evidence suggests that the sleep-dependent consolidation of declarative memory relies on the nonrapid eye movement rather than the rapid eye movement phase of sleep. In addition, it is known that aging is accompanied by changes in sleep and memory processes. Hence, the purpose of this study was to investigate the overnight consolidation of declarative memory in healthy elderly women. Sleep laboratory of University. Nineteen healthy elderly women (age range: 61-74 years). We used laboratory-based measures of sleep. To test declarative memory, the Rey-Osterrieth Complex Figure Test was performed. Declarative memory performance in elderly women was associated with Stage 2 sleep spindle density. Women characterized by high memory performance exhibited significantly higher numbers of sleep spindles and higher spindle density compared with women with generally low memory performance. The data strongly support theories suggesting a link between sleep spindle activity and declarative memory consolidation.

  12. Retino-hypothalamic regulation of light-induced murine sleep

    Directory of Open Access Journals (Sweden)

    Fanuel eMuindi

    2014-08-01

    Full Text Available The temporal organization of sleep is regulated by an interaction between the circadian clock and homeostatic processes. Light indirectly modulates sleep through its ability to phase shift and entrain the circadian clock. Light can also exert a direct, circadian-independent effect on sleep. For example, acute exposure to light promotes sleep in nocturnal animals and wake in diurnal animals. The mechanisms whereby light directly influences sleep and arousal are not well understood. In this review, we discuss the direct effect of light on sleep at the level of the retina and hypothalamus in rodents. We review murine data from recent publications showing the roles of rod-, cone- and melanopsin-based photoreception on the initiation and maintenance of light-induced sleep. We also present hypotheses about hypothalamic mechanisms that have been advanced to explain the acute control of sleep by light. Specifically, we review recent studies assessing the roles of the ventrolateral preoptic area and the suprachiasmatic nucleus. We also discuss how light might differentially promote sleep and arousal in nocturnal and diurnal animals respectively. Lastly, we suggest new avenues for research on this topic which is still in its early stages.

  13. Sleep, Memory & Brain Rhythms.

    Science.gov (United States)

    Watson, Brendon O; Buzsáki, György

    2015-01-01

    Sleep occupies roughly one-third of our lives, yet the scientific community is still not entirely clear on its purpose or function. Existing data point most strongly to its role in memory and homeostasis: that sleep helps maintain basic brain functioning via a homeostatic mechanism that loosens connections between overworked synapses, and that sleep helps consolidate and re-form important memories. In this review, we will summarize these theories, but also focus on substantial new information regarding the relation of electrical brain rhythms to sleep. In particular, while REM sleep may contribute to the homeostatic weakening of overactive synapses, a prominent and transient oscillatory rhythm called "sharp-wave ripple" seems to allow for consolidation of behaviorally relevant memories across many structures of the brain. We propose that a theory of sleep involving the division of labor between two states of sleep-REM and non-REM, the latter of which has an abundance of ripple electrical activity-might allow for a fusion of the two main sleep theories. This theory then postulates that sleep performs a combination of consolidation and homeostasis that promotes optimal knowledge retention as well as optimal waking brain function.

  14. Sleep Apnea Detection

    Science.gov (United States)

    ... Contributors Sponsors Sponsorship Opportunities Spread the Word Shop AAP Find a Pediatrician Ages & Stages Prenatal Baby Bathing & Skin Care Breastfeeding Crying & Colic Diapers & Clothing Feeding & Nutrition Preemie Sleep ...

  15. [Sleep disorders in epilepsy].

    Science.gov (United States)

    Kotova, O V; Akarachkova, E S

    2014-01-01

    The review of the literature on sleep disorders in epilepsy over the last two decades is presented. Paroxysmal phenomena of epileptic origin, nonepileptic paroxysms, antiepileptic drugs, polypragmasia and comorbid depression may affect sleep in epilepsy.Shortening of sleep time may cause seizures, hallucinations and depression because sleep plays an important role in the regulation of excitatory and inhibitory processes in the brain both in healthy people and in patients with epilepsy. According to the literature data, drugs (short treatment courses of hypnotics) or nonpharmacological methods should be used for treatment insomnia inpatients with epilepsy.

  16. Sleep Disorders: Insomnia.

    Science.gov (United States)

    Burman, Deepa

    2017-09-01

    Insomnia is the most common type of sleep disorder in the family medicine population. It is defined as a persistent difficulty initiating or maintaining sleep, or a report of nonrestorative sleep, accompanied by related daytime impairment. Insomnia is a significant public health problem because of its high prevalence and management challenges. There is increasing evidence of a strong association between insomnia and various medical and psychiatric comorbidities. Diagnosis of insomnia and treatment planning rely on a thorough sleep history to address contributing and precipitating factors as well as maladaptive behaviors resulting in poor sleep. Using a sleep diary or sleep log is more accurate than patient recall to determine sleep patterns. A sleep study is not routinely indicated for evaluation of insomnia. Cognitive behavioral therapy for insomnia (CBT-I) is the mainstay of treatment and is a safe and effective approach. The key challenge of CBT-I is the lack of clinicians to implement it. The newer generation nonbenzodiazepines (eg, zolpidem, zaleplon) are used as first-line pharmacotherapy for chronic insomnia. Newer drugs active on targets other than the gamma-aminobutyric acid receptor are now available, but clear treatment guidelines are needed. Written permission from the American Academy of Family Physicians is required for reproduction of this material in whole or in part in any form or medium.

  17. Sleep and Women

    Science.gov (United States)

    ... Stroke Pregnancy Cognitive Development parenting poor sleep Work stress Time change beds School Symptoms mental fatigue Headache mortality pain Apetite Technology Telemedicine Movies Imported Diagnostics ...

  18. Distinct effects of IPSU and suvorexant on mouse sleep architecture

    Directory of Open Access Journals (Sweden)

    Daniel eHoyer

    2013-12-01

    Full Text Available Dual orexin receptor (OXR antagonists (DORAs such as almorexant, SB-649868, suvorexant (MK-4305 and filorexant (MK-6096, have shown promise for the treatment of insomnias and sleep disorders. Whether antagonism of both OX1R and OX2R is necessary for sleep induction has been a matter of some debate. Experiments using knockout mice suggest that it may be sufficient to antagonize only OX2R. The recent identification of an orally bioavailable, brain penetrant OX2R preferring antagonist 2-((1H-Indol-3-ylmethyl-9-(4-methoxypyrimidin-2-yl-2,9-diazaspiro[5.5]undecan-1-one (IPSU has allowed us to test whether selective antagonism of OX2R may also be a viable strategy for induction of sleep. We previously demonstrated that IPSU and suvorexant increase sleep when dosed during the mouse active phase (lights off; IPSU inducing sleep primarily by increasing NREM sleep, suvorexant primarily by increasing REM sleep. Here, our goal was to determine whether suvorexant and IPSU affect sleep architecture independently of overall sleep induction. We therefore tested suvorexant (25 mg/kg and IPSU (50 mg/kg in mice during the inactive phase (lights on when sleep is naturally more prevalent and when orexin levels are normally low. Whereas IPSU was devoid of effects on the time spent in NREM or REM, suvorexant substantially disturbed the sleep architecture by selectively increasing REM during the first 4 hours after dosing. At the doses tested, suvorexant significantly decreased wake only during the first hour and IPSU did not affect wake time. These data suggest that OX2R preferring antagonists may have a reduced tendency for perturbing NREM/REM architecture in comparison with DORAs. Whether this effect will prove to be a general feature of OX2R antagonists versus DORAs remains to be seen.

  19. Consolidating the effects of waking and sleep on motor-sequence learning.

    Science.gov (United States)

    Brawn, Timothy P; Fenn, Kimberly M; Nusbaum, Howard C; Margoliash, Daniel

    2010-10-20

    Sleep is widely believed to play a critical role in memory consolidation. Sleep-dependent consolidation has been studied extensively in humans using an explicit motor-sequence learning paradigm. In this task, performance has been reported to remain stable across wakefulness and improve significantly after sleep, making motor-sequence learning the definitive example of sleep-dependent enhancement. Recent work, however, has shown that enhancement disappears when the task is modified to reduce task-related inhibition that develops over a training session, thus questioning whether sleep actively consolidates motor learning. Here we use the same motor-sequence task to demonstrate sleep-dependent consolidation for motor-sequence learning and explain the discrepancies in results across studies. We show that when training begins in the morning, motor-sequence performance deteriorates across wakefulness and recovers after sleep, whereas performance remains stable across both sleep and subsequent waking with evening training. This pattern of results challenges an influential model of memory consolidation defined by a time-dependent stabilization phase and a sleep-dependent enhancement phase. Moreover, the present results support a new account of the behavioral effects of waking and sleep on explicit motor-sequence learning that is consistent across a wide range of tasks. These observations indicate that current theories of memory consolidation that have been formulated to explain sleep-dependent performance enhancements are insufficient to explain the range of behavioral changes associated with sleep.

  20. Survey the effect of Zumba training on sleep quality in overweight girls

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    A. Zar

    2017-04-01

    Full Text Available Background: Poor quality sleep impairs the function of different parts of the body. Some studies have shown that physical activity can effect on the quality of sleep. Objective: The aim of study was to investigate the effect of Zumba training on sleep quality in obese girls. Methods: This cross - sectional study was conducted on 30 volunteered overweight girls participated in Zumba training in Shiraz Arta Club in summer 2016. Information via demographic characteristics questionnaire and standard questionnaire Pittsburgh Sleep Quality Index (PSQI were collected. Kolmogorov-Smirnov test and independent t-test (α=0.05 were used to analyze the data. Findings: The results showed that active overweight girls compared to inactive were in a better position in measures of sleep quality (P=0.01, delays in falling asleep (P=0.02, go to sleep duration (P=0.02, effective sleep (P=0.03, sleep disorders (P=0.01, the hypnotic drug consumption (P=0.04, dysfunction in the morning (P=0.03, the overall quality of sleep (P=0.01. Conclusion: In general, this study showed that Zumba training improves the quality of sleep in overweight girls. Therefore, the use of zumba training for overweight girls is recommended as a non-drug therapy to improve sleep quality.

  1. The Effect of Sleep on Children’s Word Retention and Generalization

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    Emma L. Axelsson

    2016-08-01

    Full Text Available In the first few years of life children spend a good proportion of time sleeping as well as acquiring the meanings of hundreds of words and their related associations. There is now ample evidence of the effects of sleep on memory in adults and the number of studies demonstrating the effects of napping and nocturnal sleep in children is also mounting. In particular, sleep appears to benefit children’s memory for recently-encountered novel words. The effect of sleep on children’s generalization of novel words across multiple items, however, is less clear. Given that sleep is polyphasic in the early years, made up of multiple episodes, and children’s word learning is gradual and strengthened slowly over time, it is highly plausible that sleep is a strong candidate in supporting children’s memory for novel words. Importantly, it appears that when children sleep shortly after exposure to novel word-object pairs retention is better than if sleep is delayed, suggesting that napping plays a vital role in long-term word retention for young children. Word learning is a complex, challenging and important part of development, thus the role that sleep plays in children’s retention of novel words is worthy of attention. As such, ensuring children get sufficient good quality sleep and regular opportunities to nap may be critical for strong language acquisition.

  2. Sleep/wake dependent changes in cortical glucose concentrations.

    Science.gov (United States)

    Dash, Michael B; Bellesi, Michele; Tononi, Giulio; Cirelli, Chiara

    2013-01-01

    Most of the energy in the brain comes from glucose and supports glutamatergic activity. The firing rate of cortical glutamatergic neurons, as well as cortical extracellular glutamate levels, increase with time spent awake and decline throughout non rapid eye movement sleep, raising the question whether glucose levels reflect behavioral state and sleep/wake history. Here chronic (2-3 days) electroencephalographic recordings in the rat cerebral cortex were coupled with fixed-potential amperometry to monitor the extracellular concentration of glucose ([gluc]) on a second-by-second basis across the spontaneous sleep-wake cycle and in response to 3 h of sleep deprivation. [Gluc] progressively increased during non rapid eye movement sleep and declined during rapid eye movement sleep, while during wake an early decline in [gluc] was followed by an increase 8-15 min after awakening. There was a significant time of day effect during the dark phase, when rats are mostly awake, with [gluc] being significantly lower during the last 3-4 h of the night relative to the first 3-4 h. Moreover, the duration of the early phase of [gluc] decline during wake was longer after prolonged wake than after consolidated sleep. Thus, the sleep/wake history may affect the levels of glucose available to the brain upon awakening. © 2012 The Authors Journal of Neurochemistry © 2012 International Society for Neurochemistry.

  3. Relationships between school start time, sleep duration, and adolescent behaviors.

    Science.gov (United States)

    Wahlstrom, Kyla L; Berger, Aaron T; Widome, Rachel

    2017-06-01

    The objectives were 2-fold: (1) to examine how high school start times relate to adolescent sleep duration, and (2) to test associations between sleep duration and mental health- and substance use-related issues and behaviors in teens. This study examines selected questions from survey data collected between 2010 and 2013 high school students. Respondents included more than 9000 students in grades 9 to 12 in 8 high schools in 5 school districts across the United States. The survey instrument is the 97-item Teen Sleep Habits Survey. Logistic regression models were used to calculate adjusted odds ratios and 95% confidence intervals. Because of clustering within schools and the use of repeated measures, generalized estimating equations were used to account for variance inflation. Greater sleep duration was associated with fewer reports of various mental health- and substance use-related issues and behaviors (all P values sleep reported, there was a 28% reduction in the adjusted odds of a participant reporting that he or she felt "unhappy, sad, or depressed." Later wake-up times were associated with a reduction in risk for some, but not all factors. Later start times were significantly associated with greater sleep duration. Given that later start times allow for greater sleep duration and that adequate sleep duration is associated with more favorable mental health- and substance use-related issues and behaviors, it is important that school districts prioritize exploring and implementing policies, such as delayed start times, that may increase the amount of sleep of adolescent students, which is needed for their optimal development. Copyright © 2017 National Sleep Foundation. Published by Elsevier Inc. All rights reserved.

  4. Delayed onset of a daytime nap facilitates retention of declarative memory.

    Directory of Open Access Journals (Sweden)

    Sara E Alger

    Full Text Available BACKGROUND: Learning followed by a period of sleep, even as little as a nap, promotes memory consolidation. It is now generally recognized that sleep facilitates the stabilization of information acquired prior to sleep. However, the temporal nature of the effect of sleep on retention of declarative memory is yet to be understood. We examined the impact of a delayed nap onset on the recognition of neutral pictorial stimuli with an added spatial component. METHODOLOGY/PRINCIPAL FINDINGS: Participants completed an initial study session involving 150 neutral pictures of people, places, and objects. Immediately following the picture presentation, participants were asked to make recognition judgments on a subset of "old", previously seen, pictures versus intermixed "new" pictures. Participants were then divided into one of four groups who either took a 90-minute nap immediately, 2 hours, or 4 hours after learning, or remained awake for the duration of the experiment. 6 hours after initial learning, participants were again tested on the remaining "old" pictures, with "new" pictures intermixed. CONCLUSIONS/SIGNIFICANCE: Interestingly, we found a stabilizing benefit of sleep on the memory trace reflected as a significant negative correlation between the average time elapsed before napping and decline in performance from test to retest (p = .001. We found a significant interaction between the groups and their performance from test to retest (p = .010, with the 4-hour delay group performing significantly better than both those who slept immediately and those who remained awake (p = .044, p = .010, respectively. Analysis of sleep data revealed a significant positive correlation between amount of slow wave sleep (SWS achieved and length of the delay before sleep onset (p = .048. The findings add to the understanding of memory processing in humans, suggesting that factors such as waking processing and homeostatic increases in need for sleep over time modulate

  5. The Circadian System Contributes to Apnea Lengthening across the Night in Obstructive Sleep Apnea.

    Science.gov (United States)

    Butler, Matthew P; Smales, Carolina; Wu, Huijuan; Hussain, Mohammad V; Mohamed, Yusef A; Morimoto, Miki; Shea, Steven A

    2015-11-01

    To test the hypothesis that respiratory event duration exhibits an endogenous circadian rhythm. Within-subject and between-subjects. Inpatient intensive physiologic monitoring unit at the Brigham and Women's Hospital. Seven subjects with moderate/severe sleep apnea and four controls, age 48 (SD = 12) years, 7 males. Subjects completed a 5-day inpatient protocol in dim light. Polysomnography was recorded during an initial control 8-h night scheduled at the usual sleep time, then through 10 recurrent cycles of 2 h 40 min sleep and 2 h 40 min wake evenly distributed across all circadian phases, and finally during another 8-h control sleep period. Event durations, desaturations, and apnea-hypopnea index for each sleep opportunity were assessed according to circadian phase (derived from salivary melatonin), time into sleep, and sleep stage. Average respiratory event durations in NREM sleep significantly lengthened across both control nights (21.9 to 28.2 sec and 23.7 to 30.2 sec, respectively). During the circadian protocol, event duration in NREM increased across the circadian phases that corresponded to the usual sleep period, accounting for > 50% of the increase across normal 8-h control nights. AHI and desaturations were also rhythmic: AHI was highest in the biological day while desaturations were greatest in the biological night. The endogenous circadian system plays an important role in the prolongation of respiratory events across the night, and might provide a novel therapeutic target for modulating sleep apnea. © 2015 Associated Professional Sleep Societies, LLC.

  6. Middle school start times: the importance of a good night's sleep for young adolescents.

    Science.gov (United States)

    Wolfson, Amy R; Spaulding, Noah L; Dandrow, Craig; Baroni, Elizabeth M

    2007-01-01

    With the onset of adolescence, teenagers require 9.2 hr of sleep and experience a delay in the timing of sleep. In the "real world" with early school start times, however, they report less sleep, striking differences between their school-weekend sleep schedules, and significant daytime sleepiness. Prior studies demonstrated that high schoolers with later school starts do not further delay bedtime but obtain more sleep due to later wake times. This study examined sleep-wake patterns of young adolescents attending urban, public middle schools with early (7:15 a.m.) versus late (8:37 a.m.) start times. Students (N = 205) were assessed at 2 time periods. Students at the late-starting school reported waking up over 1 hr later on school mornings and obtaining 50 min more sleep each night, less sleepiness, and fewer tardies than students at the early school. All students reported similar school-night bedtime, sleep hygiene practices, and weekend sleep schedules.

  7. Assessment of Sleep Quantity and Sleep Disturbances During Recovery From Sports-Related Concussion in Youth Athletes.

    Science.gov (United States)

    Murdaugh, Donna L; Ono, Kim E; Reisner, Andrew; Burns, Thomas G

    2018-05-01

    To determine the relation between sleep quantity and sleep disturbances on symptoms and neurocognitive ability during the acute phase (sports-related concussion (SRC; >21d). Prospective inception cohort study. General community setting of regional middle and high schools. A sample (N=971) including youth athletes with SRC (n=528) and controls (n=443) (age, 10-18y). Not applicable. Athletes completed the Immediate Post-Concussion Assessment and Cognitive Testing battery. Partial correlation analyses and independent t tests were conducted to assess sleep quantity the night before testing. Multivariate analysis of covariance was used to assess sleep disturbances and their interaction with age. Less sleep quantity was correlated with greater report of cognitive (P=.001) and neuropsychological (P=.024) symptoms specific to prolonged recovery from SRC. Sleep disturbances significantly affect each migraine, cognitive, and neuropsychological symptoms (Psleep disturbances and age (P=.04) at >21 days post-SRC. Findings emphasize that the continued presence of low sleep quantity and sleep disturbances in youth athletes with SRC should be a specific indicator to health professionals that these athletes are at an increased risk of protracted recovery. Further research should identify additional factors that may interact with sleep to increase the risk of protracted recovery. Copyright © 2018 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  8. Effect of Daytime Exercise on Sleep Eeg and Subjective Sleep

    Science.gov (United States)

    Sasazawa, Y.; Kawada, T.; Kiryu, Y.

    1997-08-01

    This study was designed to assess the effects of daytime physical exercise on the quality of objective and subjective sleep by examining all-night sleep EEGs. The subjects were five male students, aged 19 to 20 years, who were in the habit of performing regular daytime exercise. The sleep polygraphic parameters in this study were sleep stage time as a percentage of total sleep time (%S1, %S2, %S(3+4), %SREM, %MT), time in bed (TIB), sleep time (ST), total sleep time (TST), sleep onset latency (SOL), waking from sleep, sleep efficiency, number of awakenings, number of stage shifts, number of spindles, and percentages of α and δ waves, all of which were determined by an automatic computer analysis system. The OSA questionnaire was used to investigate subjective sleep. The five scales of the OSA used were sleepiness, sleep maintenance, worry, integrated sleep feeling, and sleep initiation. Each sleep parameter was compared in the exercise and the non-exercise groups. Two-way analysis of variance was applied using subject factor and exercise factor. The main effect of the subject was significant in all parameters and the main effect of exercise in %S(3+4), SOL and sleep efficiency, among the objective sleep parameters. The main effects of the subject, except sleepiness, were significant, as was the main effect of exercise on sleep initiation, among the subjective sleep parameters. These findings suggest that daytime exercise shortened sleep latency and prolonged slow-wave sleep, and that the subjects fell asleep more easily on exercise days. There were also significant individual differences in both the objective and subjective sleep parameters.

  9. Unihemispheric sleep and asymmetrical sleep: behavioral, neurophysiological, and functional perspectives

    Directory of Open Access Journals (Sweden)

    Mascetti GG

    2016-07-01

    Full Text Available Gian Gastone Mascetti Department of General Psychology, University of Padova, Padova, Italy Abstract: Sleep is a behavior characterized by a typical body posture, both eyes' closure, raised sensory threshold, distinctive electrographic signs, and a marked decrease of motor activity. In addition, sleep is a periodically necessary behavior and therefore, in the majority of animals, it involves the whole brain and body. However, certain marine mammals and species of birds show a different sleep behavior, in which one cerebral hemisphere sleeps while the other is awake. In dolphins, eared seals, and manatees, unihemispheric sleep allows them to have the benefits of sleep, breathing, thermoregulation, and vigilance. In birds, antipredation vigilance is the main function of unihemispheric sleep, but in domestic chicks, it is also associated with brain lateralization or dominance in the control of behavior. Compared to bihemispheric sleep, unihemispheric sleep would mean a reduction of the time spent sleeping and of the associated recovery processes. However, the behavior and health of aquatic mammals and birds does not seem at all impaired by the reduction of sleep. The neural mechanisms of unihemispheric sleep are unknown, but assuming that the neural structures involved in sleep in cetaceans, seals, and birds are similar to those of terrestrial mammals, it is suggested that they involve the interaction of structures of the hypothalamus, basal forebrain, and brain stem. The neural mechanisms promoting wakefulness dominate one side of the brain, while those promoting sleep predominates the other side. For cetaceans, unihemispheric sleep is the only way to sleep, while in seals and birds, unihemispheric sleep events are intermingled with bihemispheric and rapid eye movement sleep events. Electroencephalogram hemispheric asymmetries are also reported during bihemispheric sleep, at awakening, and at sleep onset, as well as being associated with a use

  10. Digital Media and Sleep in Childhood and Adolescence.

    Science.gov (United States)

    LeBourgeois, Monique K; Hale, Lauren; Chang, Anne-Marie; Akacem, Lameese D; Montgomery-Downs, Hawley E; Buxton, Orfeu M

    2017-11-01

    Given the pervasive use of screen-based media and the high prevalence of insufficient sleep among American youth and teenagers, this brief report summarizes the literature on electronic media and sleep and provides research recommendations. Recent systematic reviews of the literature reveal that the vast majority of studies find an adverse association between screen-based media consumption and sleep health, primarily via delayed bedtimes and reduced total sleep duration. The underlying mechanisms of these associations likely include the following: (1) time displacement (ie, time spent on screens replaces time spent sleeping and other activities); (2) psychological stimulation based on media content; and (3) the effects of light emitted from devices on circadian timing, sleep physiology, and alertness. Much of our current understanding of these processes, however, is limited by cross-sectional, observational, and self-reported data. Further experimental and observational research is needed to elucidate how the digital revolution is altering sleep and circadian rhythms across development (infancy to adulthood) as pathways to poor health, learning, and safety outcomes (eg, obesity, depression, risk-taking). Copyright © 2017 by the American Academy of Pediatrics.

  11. Sleep-dependent modulation of affectively guided decision-making.

    Science.gov (United States)

    Pace-Schott, Edward F; Nave, Genevieve; Morgan, Alexandra; Spencer, Rebecca M C

    2012-02-01

    A question of great interest in current sleep research is whether and how sleep might facilitate complex cognitive skills such as decision-making. The Iowa Gambling Task (IGT) was used to investigate effects of sleep on affect-guided decision-making. After a brief standardized preview of the IGT that was insufficient to learn its underlying rule, participants underwent a 12-h delay containing either a normal night's sleep (Sleep group; N = 28) or continuous daytime wake (Wake group; N = 26). Following the delay, both groups performed the full IGT. To control for circadian effects, two additional groups performed both the preview and the full task either in the morning (N = 17) or the evening (N = 21). In the IGT, four decks of cards were presented. Draws from two 'advantageous decks' yielded low play-money rewards, occasional low losses and, over multiple draws, a net gain. Draws from 'disadvantageous' decks yielded high rewards, occasional high losses and, over multiple draws, a net loss. Participants were instructed to win and avoid losing as much as possible, and better performance was defined as more advantageous draws. Relative to the wake group, the sleep group showed both superior behavioral outcome (more advantageous draws) and superior rule understanding (blindly judged from statements written at task completion). Neither measure differentiated the two control groups. These results illustrate a role of sleep in optimizing decision-making, a benefit that may be brought about by changes in underlying emotional or cognitive processes. © 2011 European Sleep Research Society.

  12. Sleep disorders and work performance: findings from the 2008 National Sleep Foundation Sleep in America poll.

    Science.gov (United States)

    Swanson, Leslie M; Arnedt, J Todd; Rosekind, Mark R; Belenky, Gregory; Balkin, Thomas J; Drake, Christopher

    2011-09-01

    Chronic sleep deprivation is common among workers, and has been associated with negative work outcomes, including absenteeism and occupational accidents. The objective of the present study is to characterize reciprocal relationships between sleep and work. Specifically, we examined how sleep impacts work performance and how work affects sleep in individuals not at-risk for a sleep disorder; assessed work performance outcomes for individuals at-risk for sleep disorders, including insomnia, obstructive sleep apnea (OSA) and restless legs syndrome (RLS); and characterized work performance impairments in shift workers (SW) at-risk for shift work sleep disorders relative to SW and day workers. One-thousand Americans who work 30 h per week or more were asked questions about employment, work performance and sleep in the National Sleep Foundation's 2008 Sleep in America telephone poll. Long work hours were associated with shorter sleep times, and shorter sleep times were associated with more work impairments. Thirty-seven percent of respondents were classified as at-risk for any sleep disorder. These individuals had more negative work outcomes as compared with those not at-risk for a sleep disorder. Presenteeism was a significant problem for individuals with insomnia symptoms, OSA and RLS as compared with respondents not at-risk. These results suggest that long work hours may contribute to chronic sleep loss, which may in turn result in work impairment. Risk for sleep disorders substantially increases the likelihood of negative work outcomes, including occupational accidents, absenteeism and presenteeism. © 2010 European Sleep Research Society.

  13. The Biology of REM Sleep

    Science.gov (United States)

    Peever, John; Fuller, Patrick M.

    2018-01-01

    Considerable advances in our understanding of the mechanisms and functions of rapid-eye-movement (REM) sleep have occurred over the past decade. Much of this progress can be attributed to the development of new neuroscience tools that have enabled high-precision interrogation of brain circuitry linked with REM sleep control, in turn revealing how REM sleep mechanisms themselves impact processes such as sensorimotor function. This review is intended to update the general scientific community about the recent mechanistic, functional and conceptual developments in our current understanding of REM sleep biology and pathobiology. Specifically, this review outlines the historical origins of the discovery of REM sleep, the diversity of REM sleep expression across and within species, the potential functions of REM sleep (e.g., memory consolidation), the neural circuits that control REM sleep, and how dysfunction of REM sleep mechanisms underlie debilitating sleep disorders such as REM sleep behaviour disorder and narcolepsy. PMID:26766231

  14. The impact of prolonged violent video-gaming on adolescent sleep: an experimental study.

    Science.gov (United States)

    King, Daniel L; Gradisar, Michael; Drummond, Aaron; Lovato, Nicole; Wessel, Jason; Micic, Gorica; Douglas, Paul; Delfabbro, Paul

    2013-04-01

    Video-gaming is an increasingly prevalent activity among children and adolescents that is known to influence several areas of emotional, cognitive and behavioural functioning. Currently there is insufficient experimental evidence about how extended video-game play may affect adolescents' sleep. The aim of this study was to investigate the short-term impact of adolescents' prolonged exposure to violent video-gaming on sleep. Seventeen male adolescents (mean age = 16 ± 1 years) with no current sleep difficulties played a novel, fast-paced, violent video-game (50 or 150 min) before their usual bedtime on two different testing nights in a sleep laboratory. Objective (polysomnography-measured sleep and heart rate) and subjective (single-night sleep diary) measures were obtained to assess the arousing effects of prolonged gaming. Compared with regular gaming, prolonged gaming produced decreases in objective sleep efficiency (by 7 ± 2%, falling below 85%) and total sleep time (by 27 ± 12 min) that was contributed by a near-moderate reduction in rapid eye movement sleep (Cohen's d = 0.48). Subjective sleep-onset latency significantly increased by 17 ± 8 min, and there was a moderate reduction in self-reported sleep quality after prolonged gaming (Cohen's d = 0.53). Heart rate did not differ significantly between video-gaming conditions during pre-sleep game-play or the sleep-onset phase. Results provide evidence that prolonged video-gaming may cause clinically significant disruption to adolescent sleep, even when sleep after video-gaming is initiated at normal bedtime. However, physiological arousal may not necessarily be the mechanism by which technology use affects sleep. © 2012 European Sleep Research Society.

  15. Delayed orgasm and anorgasmia.

    Science.gov (United States)

    Jenkins, Lawrence C; Mulhall, John P

    2015-11-01

    Delayed orgasm/anorgasmia defined as the persistent or recurrent difficulty, delay in, or absence of attaining orgasm after sufficient sexual stimulation, which causes personal distress. Delayed orgasm and anorgasmia are associated with significant sexual dissatisfaction. A focused medical history can shed light on the potential etiologies, which include medications, penile sensation loss, endocrinopathies, penile hyperstimulation, and psychological etiologies. Unfortunately, there are no excellent pharmacotherapies for delayed orgasm/anorgasmia, and treatment revolves largely around addressing potential causative factors and psychotherapy. Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  16. Increased deep sleep in a medication-free, detoxified female offender with schizophrenia, alcoholism and a history of attempted homicide: Case report

    Directory of Open Access Journals (Sweden)

    Sailas Eila

    2004-10-01

    Full Text Available Abstract Background Psychiatric sleep research has attempted to identify diagnostically sensitive and specific sleep patterns associated with particular disorders. Both schizophrenia and alcoholism are typically characterized by a severe sleep disturbance associated with decreased amounts of slow wave sleep, the physiologically significant, refreshing part of the sleep. Antisocial behaviour with severe aggression, on the contrary, has been reported to associate with increased deep sleep reflecting either specific brain pathology or a delay in the normal development of sleep patterns. The authors are not aware of previous sleep studies in patients with both schizophrenia and antisocial personality disorder. Case presentation The aim of the present case-study was to characterize the sleep architecture of a violent, medication-free and detoxified female offender with schizophrenia, alcoholism and features of antisocial personality disorder using polysomnography. The controls consisted of three healthy, age-matched women with no history of physical violence. The offender's sleep architecture was otherwise