Wake Parameters Research Articles

The reliability and validity of the Japanese version of the Children's ChronoType Questionnaire (CCTQ) in preschool children

We aimed to examine the reliability and validity of the Japanese version of the Children's ChronoType Questionnaire (CCTQ) in preschool children. The CCTQ consists of 16 items on sleep–wake parameters for scheduled and free days, a 10-item of the Morningness/Eveningness Scale (CCTQ-M/E), and a single item on chronotype. Out of 502 children aged 3–6 years living in Okayama Prefecture, we evaluated 346 (188 boys and 158 girls) between May and June 2012. Their parents filled out the questionnaires two times at an interval of two weeks. Cronbach's α of the CCTQ-M/E was 0.77. For test–retest reliability, Pearson's correlation coefficient of the CCTQ-M/E between the two observations was 0.898 (p < 0.001). Kruskal–Wallis test with post-hoc tests was used to compare sleep–wake parameters measured with the CCTQ among the three groups of children, morning (M)-type, neither (N)-type and evening (E)-type, who were classified according to the CCTQ-M/E score. Sleep–wake parameters in timing were significantly different among the children with M-type, N-type and E-type (p < 0.001). Post-hoc pairwise comparisons revealed that sleep–wake parameters in timing were significantly delayed from the M-type to the N-type children (p < 0.001), from the M-type to the E-type children (p < 0.001), and from the N-type to the E-type children (p < 0.001), except that wake-up time and get-up time were not significantly different between the children with N-type and E-type on scheduled days when their start time was regularly fixed. Out of these 346 children, we evaluated 72 (35 boys and 37 girls) to see the correlations between subjectively and objectively measured sleep–wake parameters from June to October 2012. Spearman's correlation coefficients between sleep–wake parameters measured with the CCTQ and an actigraph were 0.512–0.836 on scheduled days (p < 0.001) and 0.380–0.786 on free days (p < 0.001). Based on these findings we conclude that the Japanese version of the CCTQ is a reliable and valid measure for assessing chronotypes in preschool children.

Experimental Investigation of Turbulence Promoters Effect on Characteristics of Linear Cascade Compressor

In this paper, considering the importance of inlet flow turbulence intensity in the combustion chamber, the effect of flow turbulence on characteristics of the flow wake within a linear compressor cascade has been experimentally investigated. To this purpose, two wires were installed along each blade an d their effects on average velocity, turbulence intensity at Re. Number 45500 were studied. One–dimensional hot wire anemometer was used to measure wake parameters. The results showed that turbulence promoters increased the maximum turbulence intensity in blades wake.

Tasimelteon treatment entrains the circadian clock and demonstrates significant benefit on sleep and wake parameters in totally blind individuals with non-24 hour circadian rhythms

The majority of totally blind individuals exhibit non-24-h circadian rhythms due to light signals not reaching the suprachiasmatic nucleus, resulting in Non-24-h Sleep–Wake Disorder (Non-24), a serious circadian rhythm disorder with no approved treatment. Tasimelteon is a novel circadian regulator in development for Non-24 with selective agonist activity for melatonin MT1 and MT2 receptors. Two phase III placebo-controlled studies in blind Non-24 patients assessed safety, efficacy and maintenance of effect of tasimelteon treatment (20 mg/day). Circadian period was assessed from urinary 6-sulfatoxymelatonin (aMT6s) and cortisol. Clinical assessments included a Non-24 Clinical Response Scale (N24CRS), nighttime sleep, daytime naps and Clinical Global Impression of Change (CGIC). Entrainment Study (SET) ( n = 84): Tasimelteon entrained the circadian clock (aMT6s: 20.0% vs. 2.6%; cortisol: 17.5% vs. 2.6%), had more clinical responders on the N24CRS (23.7 vs. 0%), improved CGIC (2.6% vs. 3.4), increased sleep in the worst quartile of nights (LQ-nTST) (57% vs. 17 min), and decreased nap duration in the worst quartile of days (UQ-dTSD) (46% vs. 18 min), compared to placebo ( p < 0.05). Maintenance Study (RESET) ( n = 20): Tasimelteon-entrained patients were randomized to continued treatment or placebo. Tasimelteon maintained entrainment compared to placebo (aMT6s: 90% vs. 20%; cortisol: 80% vs. 20%). In treated patients, nighttime sleep (LQ-nTST) increased, and daytime sleep (UQ-dTSD) decreased, by 67 and 59 min/day, respectively ( p < 0.05). During the run-in phase of the study, the rate of entrainment among tasimelteon treated patients ranged from 55% to 75% in subpopulation sensitivity analysis. Tasimelteon was safe and well-tolerated in both studies. Tasimelteon entrained the circadian pacemaker in blind patients with Non-24, and caused significant clinical improvement in multiple measures of sleep, wake and global functioning. Discontinuation of tasimelteon abolished circadian entrainment, resulting in an hour less sleep each night and an hour more sleep each day. These studies demonstrate that tasimelteon is an effective circadian regulator, and that continued treatment is required to maintain entrainment and the resulting clinical benefits. Support for the study was provided by Vanda Pharmaceuticals Inc. (ClinicalTrials.gov NCT01163032 and NCT01430754). Statistical and Analytical Support was provided by Dennis Fisher at ”P Less Than” company.

Numerical simulation of force and wake mode of an oscillating cylinder

The turbulent flow behind a circular cylinder subjected to forced oscillation is numerically studied at a Reynolds number of 5500 by using three-dimensional Large Eddy Simulations (3-D LES) technique with the Smagorinsky model. The filtered equations are discretised using the finite volume method with an O-type structured grid and a second-order accurate method in both time and space. Firstly, the main wake parameters of a stationary cylinder are examined and compared in the different grid resolutions. Secondly, a transversely oscillating cylinder with a constant amplitude in a uniform flow is investigated. The cylinder oscillation frequency ranges between 0.75 and 0.95 of the natural Kármán frequency, and the excitation amplitude is moderate, 50% of the cylinder diameter. The flow characteristics of an oscillating cylinder are numerically examined and the corresponding wake modes are captured firstly in 3-D LES at Re=5500. A transition between different wake modes is firstly investigated in a set of numerical simulations.

Intragastric administration of glutamate increases REM sleep in rats

Monosodium glutamate, a umami taste substance is commonly used flavor enhancer. The effect of intragastric administration of 1.5ml of 0.12M monosodium glutamate on sleep–wake was studied in 10 adult male Wistar rats. Sleep–wake parameters were recorded through chronically implanted electroencephalogram, electrooculogram and electromyogram electrodes using a digital recording system (BIOPAC system Inc. BSL PRO 36, USA). The sleep–wake was recorded for 6h after the intragastric administration of either glutamate or saline. Sleep–wake stages were analyzed as wake, slow wave sleep and REM sleep. Compared to saline, intragastric administration of glutamate significantly increased REM sleep duration and episode frequency. REM sleep duration was increased in all the three 2h bins, 10:00–12:00h (p=0.037), 12:00–14:00h (p=0.037) and 14:00–16:00h (p=0.007). The slow wave sleep and total sleep time were not affected. It is concluded that intragastric glutamate administration increases REM sleep.

Measurements of the wind turbine wake parameters with a pulsed coherent lidar under various atmospheric conditions

The strategy of measurements with a pulsed coherent Doppler lidar (PCDL) and the method of raw data processing to estimate the parameters of the wake formed behind a wind turbine downwind are suggested. Measurements with a 2-μm PCDL demonstrate that depending on the atmospheric conditions, the operating wind turbine generates a wake with maximum deficit of the wind velocity from 27 to 75% and longitudinal wake sizes varying from 120 to 1180 m. It is demonstrated that doubling of the turbulent energy dissipation rate causes the longitudinal size of the wake generated by the wind turbine to halve.

The effects of caffeine abstinence on sleep: A pilot study

AimThe aim of this study was to examine whether caffeine abstinence in the evening could improve the sleep quality of those who habitually consume coffee. DesignA double-blind control group design (caffeine and caffeine-free groups). SettingA university. SubjectsA convenience sampling of 10 students (mean age 21.4years). MethodsIt was a 14-day experiment. For the first 7days, all participants consumed caffeinated coffee. In the following 7days, subjects consumed caffeinated or decaffeinated coffee according to their assigned group. MeasuresSleep–wake parameters, self-reported sleep quality and level of refreshment. ResultsThere were no significant differences (p>.05) among the data of the two groups identified. No significant changes (p>.05) were found in the sleep quality of either group during the study. ConclusionThis study confirms that caffeine abstinence in the evening might not be helpful in sleep promotion. It highlights the need to implement evidence-based practice in health promotion.

Systematic evaluation of Axis-I DSM diagnoses in delayed sleep phase disorder and evening-type circadian preference

Alterations in circadian rhythms can have profound effects on mental health. High co-morbidity for psychiatric disorders has been observed in patients with circadian rhythm disorders, such as delayed sleep phase disorder (DSPD), and in those with an evening-type circadian preference. The aim of this study was to systematically determine the prevalence and type of Diagnostic and Statistical Manual of Mental Disorders fourth edition (DSM IV) Axis-I disorders in those with DSPD compared to evening-type controls. Forty-eight DSPD and 25 evening-type participants took part in this study. Sleep and wake parameters were assessed with actigraphy, diary and questionnaires (Pittsburgh Sleep Quality Index (PSQI) and Functional Outcomes of Sleep Questionnaire (FOSQ). Evening-type preference was defined by the Horne-Ostberg questionnaire. DSPD was determined by an interview according to International Classification of Sleep Disorders criteria. Current and past diagnoses of psychiatric disorders were assessed with a Structured Clinical Interview for DSM-IV disorders. DSPD was associated with a later wake time, longer sleep time, higher PSQI score and lower Horne-Ostberg and FOSQ scores compared to evening-types. There were no significant differences in the prevalence or type of Axis-I disorders between those with DSPD or evening-type preference. Over 70% of participants met criteria for at least one past Axis-I disorder. Approximately 40% of both the DSPD and evening-types met criteria for a past diagnosis of mood, anxiety (most frequently phobia) or substance-use disorders. Evening types were more likely to have a past diagnosis of more than one Axis-I disorder. These results highlight the important link between circadian rhythms and mental disorders. Specifically, an evening circadian chronotype regardless of DSPD status is associated with a risk for anxiety, depressive or substance-use disorders.

Comparison of agomelatine and escitalopram on nighttime sleep and daytime condition and efficacy in major depressive disorder patients

Agomelatine, an MT1/MT2 receptor agonist and 5-HT2C receptor antagonist antidepressant, is known to have beneficial effects on subjective sleep in major depressive disorder patients. This international multicenter, randomized, double-blind study compared the effects of agomelatine (25-50 mg/day) and escitalopram (10-20 mg/day) on sleep polysomnographic parameters in major depressive disorder patients treated up to 24 weeks. A total of 138 outpatients were randomly allocated to agomelatine (n=71) or escitalopram (n=67). Treatment with agomelatine was associated with a reduction in sleep latency from week 2 onward. The difference between treatments was significant on all evaluations. Rapid eye movement latency was increased with escitalopram compared with agomelatine, with significant between-group differences at every visit. Agomelatine preserved the number of sleep cycles, whereas it was decreased with escitalopram with significant between-group differences at every visit. Assessments on visual analogue scales indicated that treatment with agomelatine improved morning condition, and reduced daytime sleepiness compared with escitalopram.17-item Hamilton depression rating scale total score was reduced in both groups, agomelatine was statistically noninferior to escitalopram at 6 weeks. Both treatments were well tolerated. This study showed that the clinical effects of agomelatine on sleep and wake parameters are different from that of escitalopram.

An integrated video-analysis software system designed for movement detection and sleep analysis. Validation of a tool for the behavioural study of sleep

Objective The aim of the present study was to develop and validate a software tool for the detection of movements during sleep, based on the automated analysis of video recordings. This software is aimed to detect and quantify movements and to evaluate periods of sleep and wake. Methods We applied an open-source software, previously distributed on the web (Zoneminder, ZM), meant for video surveillance. A validation study was performed: computed movement analysis was compared with two standardised, ‘gold standard’ methods for the analysis of sleep–wake cycles: actigraphy and laboratory-based video-polysomnography. Results Sleep variables evaluated by ZM were not different from those measured by traditional sleep-scoring systems. Bland–Altman plots showed an overlap between the scores obtained with ZM, PSG and actigraphy, with a slight tendency of ZM to overestimate nocturnal awakenings. ZM showed a good degree of accuracy both with respect to PSG (79.9%) and actigraphy (83.1%); and had very high sensitivity (ZM vs. PSG: 90.4%; ZM vs. actigraphy: 89.5%) and relatively lower specificity (ZM vs. PSG: 42.3%; ZM vs. actigraphy: 65.4%). Conclusions The computer-assisted motion analysis is reliable and reproducible, and it can allow a reliable esteem of some sleep and wake parameters. The motion-based sleep analysis shows a trend to overestimate wakefulness. Significance The possibility to measure sleep from video recordings may be useful in those clinical and experimental conditions in which traditional PSG studies may not be performed.

Quinolinic acid lesions of the pedunculopontine nucleus impair sleep architecture, but not locomotion, exploration, emotionality or working memory in the rat

Anatomical and functional studies have shown that the NADPH-diaphorase-positive cholinergic neurons of the pedunculopontine nucleus (PPN) send projections to several areas in the brain. The purpose of this work was to investigate whether bilateral lesions with quinolinic acid, a neurotoxin with greater selectivity for NADPH-diaphorase-positive neurons, aimed at the compact portion of the PPN would affect the performance of adaptive behaviors, such as sleep, locomotion, and spontaneous alternation. Lesioned animals were divided in a low lesion group (LL, <50% neuron loss) and a high lesion group (HL, ≥50% neuron loss). The LL animals did not show any significant changes in sleep patterns, as compared to controls. In contrast, the HL group showed a significant increase in the number of REM sleep periods, and a reduction of REM sleep average duration, but did not differ in the total time spent in REM sleep. HL animals also showed an increase in the number of SWS periods, though wakefulness parameters did not show significant alterations. The duration and number of both REM and SWS sleep episodes were significantly correlated with the number of NADPH-diaphorase-positive neurons in the PPN. The short-term habituation pattern of locomotion, the vertical exploratory activity, as well as the thigmotaxis (an index of emotionality), displayed by LL and HL rats in a novel environment were similar to those of control animals. Likewise, there were no significant differences in spontaneous alternation among the groups. Our results indicate that quinolinic acid lesions of NADPH-diaphorase-positive cholinergic neurons localized in the posterior region of the PPN disrupt normal sleep structure, while motor activity and spontaneous alternation remain unaffected.

Closure to “Velocity Profile and Flow Resistance Models for Developing Chute Flow” by Oscar Castro-Orgaz

where κ = Karman constant; Π = wake parameter; BT 1⁄4 BF 1⁄4 8:5, a constant for fully rough channel; and WðYÞ 1⁄4 WcðYÞ þ Π WaðYÞ is the wake function. Coles (1956) proposed the main wake function WcðYÞ under boundary conditions Wcð0Þ 1⁄4 Wcð1Þ 2 1⁄4 0 subject to the normalization R 1 0 WcðYÞdY 1⁄4 1, generally adopted as WcðYÞ 1⁄4 6Y2 4Y3 with WaðYÞ≡ 0. The corrective wake function WaðYÞ, to ensure ∂u=∂z 1⁄4 0 at z 1⁄4 δ is subjected to the boundary conditions Wað0Þ 1⁄4 Wað1Þ 1⁄4 0, which predicts R 1 0 WaðYÞdY ≡ c1. In Castro-Orgaz (2009) and the work under discussion, the author adopted WaðYÞ 1⁄4 Y2 Y3, having c1 1⁄4 1=12, after Dean (1978) and Granville (1976). Further, Lewkowicz (1982) proposed WaðYÞ 1⁄4 Y2 þ 3Y3 2Y4 having ci 1⁄4 1=60, and Afzal proposed WaðYÞ 1⁄4 3Y2 þ 8Y3 5Y4 having cl 1⁄4 0 (see Afzal 1996). The displacement thickness δ 1⁄4 R δ 0 ðUe uÞ=Uedy estimated from Eqs. (1a) and (2a) yields

Volumetric reconstruction of the mean flow around circular cylinders fitted with strakes

The volumetric reconstruction technique presented in this paper employs a two-camera stereoscopic particle image velocimetry (SPIV) system in order to reconstruct the mean flow behind a fixed cylinder fitted with helical strakes, which are commonly used to suppress vortex-induced vibrations (VIV). The technique is based on the measurement of velocity fields at equivalent adjacent planes that results in pseudo volumetric fields. The main advantage over proper volumetric techniques is the avoidance of additional equipment and complexity. The averaged velocity fields behind the straked cylinders and the geometrical periodicity of the three-start configuration are used to further simplify the reconstruction process. Two straked cylindrical models with the same pitch (p = 10d) and two different heights (h = 0.1 and 0.2d) are tested. The reconstructed flow shows that the strakes introduce in the wake flow a well-defined wavelength of one-third of the pitch. Measurements of hydrodynamic forces, fluctuating velocity, vortex formation length, and vortex shedding frequency show the interdependence of the wake parameters. The vortex formation length is increased by the strakes, which is an important effect for the suppression of vortex-induced vibrations. The results presented complement previous investigations concerning the effectiveness of strakes as VIV suppressors and provide a basis of comparison to numerical simulations.

Nocturnal Sleep–Wake Parameters of Adolescents at Home Following Cancer Chemotherapy

The purpose of this descriptive, longitudinal study was to describe objective nocturnal sleep-wake parameters of adolescents at home after receiving chemotherapy in the hospital or outpatient clinic and explore differences in sleep variables by age, gender, and corticosteroid use. We collected 7 days of wrist actigraphy and sleep diary data from 48 adolescents (10-19 years) who were receiving cancer chemotherapy for a primary or secondary cancer or a relapse. The actigraphic sleep variables included rest interval (i.e., time in bed), sleep onset, sleep offset, sleep duration, total sleep time (TST), wake after sleep onset (WASO), and %WASO. Of the 48 adolescents, 38 had at least five nights of scored actigraphy and were included in analyses. Older (13-18 years) adolescents went to bed later and had fewer minutes of TST than younger adolescents (10-12 years). Exploratory analyses revealed no differences between adolescents who were taking oral corticosteroids (i.e., prednisone, dexamethasone) and those who were not or between males and females. These adolescents had sleep durations that met or exceeded the recommended sleep duration for their age groups but experienced significant WASO. Further research is needed to estimate sleep needs of adolescents during chemotherapy and determine factors that contribute to nocturnal wake-time so that targeted interventions can be designed to improve sleep quality.

A simple approximation for larval retention around reefs

Estimating larval retention at individual reefs by local scale three-dimensional flows is a significant problem for understanding, and predicting, larval dispersal. Determining larval dispersal commonly involves the use of computationally demanding and expensively calibrated/validated hydrodynamic models that resolve reef wake eddies. This study models variation in larval retention times for a range of reef shapes and circulation regimes, using a reef-scale three-dimensional hydrodynamic model. It also explores how well larval retention time can be estimated based on the “Island Wake Parameter”, a measure of the degree of flow turbulence in the wake of reefs that is a simple function of flow speed, reef dimension, and vertical diffusion. The mean residence times found in the present study (0.48–5.64 days) indicate substantial potential for self-recruitment of species whose larvae are passive, or weak swimmers, for the first several days after release. Results also reveal strong and significant relationships between the Island Wake Parameter and mean residence time, explaining 81–92% of the variability in retention among reefs across a range of unidirectional flow speeds and tidal regimes. These findings suggest that good estimates of larval retention may be obtained from relatively coarse-scale characteristics of the flow, and basic features of reef geomorphology. Such approximations may be a valuable tool for modeling connectivity and meta-population dynamics over large spatial scales, where explicitly characterizing fine-scale flows around reef requires a prohibitive amount of computation and extensive model calibration.

Exergy Analysis of Single Array Wind Farm Using Wake Effects

The influence of wake parameters on the exergy analysis of single array wind farm is studied in this paper. Key parameters which influence wake effects in a wind farm are wind velocity, tip speed ratio, number of blades, rotor speed, rotor diameter and hub height. Three different models namely power, wake and exergy model were used in estimating the exergy efficiency of the single array wind farm. Even though it is ideal for wind farms to fix the wind turbines in rows and columns the conditions of the site may not always be condu- cive for it. Hence analysis has been done keeping the wind turbines at random in a row and the effect of positioning on the performance is analyzed. Energy and exergy efficiency calculations were made for different cases by varying the positions of wind turbines in the single array wind farm. Standard relations were used in estimating the energy deficit in the wind farm due to wake effects. The wake effects were found to have an aggregated influence on the energy production of the wind farm, which results from the changes in the key parameters mentioned above. Potential areas for reducing energy losses by proper location and selection of turbines based on rating are highlighted. The influence of individual parameters contributing to the wake ef-fect were analyzed and discussed in detail.

Shedding Light on the Effectiveness of Melatonin for Circadian Rhythm Sleep Disorders

Shedding Light on the Effectiveness of Melatonin for Circadian Rhythm Sleep Disorders

Broadband Noise Due to Rotor-Wake/Rotor Interaction in Contra-Rotating Open Rotors

A semi-analytical model for the prediction of the broadband noise due to the interaction between turbulent rotor wakesandarotorincontra-rotatingopenrotorsispresented.Theunsteadyloadingoftherearrotorismodeledusing classicalisolated flat-platetheory.Striptheoryisusedtotreatthespanwisevariationsofaerodynamicquantitiesand blade geometry. The turbulent wake is assumed to be homogeneous and isotropic turbulence that is modulated by a train of wake profiles. The model is presented in detail and insight into its modal behavior is provided. A parameter study is conducted to investigate the effects of blade number, rotor–rotor gap and rotor speeds on broadband noise emissions due to rotor–wake/rotor interaction in contra-rotating open rotors. Scaling laws for sound power levels have been established analytically and show good agreement with the results of the parameter study. Nomenclature a = empirical wake parameter Bi = blade number of theith rotor bW = half-wake width, m Cd = drag coefficient of front airfoils c0 = speed of sound, m:s � 1 ci = blade chord, m cl

Transition Prediction on Turbine Blade Profile With Intermittency Transport Equation

This paper presents the results of tests and validations of the γ-Reθ model proposed by Menter et al. (2006, “A Correlation-Based Transition Model Using Local Variables—Part I: Model Formation,” ASME J. Turbomach., 128, pp. 413–422), which was extended by in-house correlations for onset location and transition length. The tests performed were based on experimental data from the flat plate test cases available at the ERCOFTAC database as well as on experimental data from the turbine blade profile investigated at Czestochowa University of Technology. Further on, the model was applied for unsteady calculations of the blade profile test case, where chosen inlet conditions (turbulent intensity and wake parameters) were applied. For the selected case, numerical results were compared not only with the experimental data but also with the results obtained with other transition models. It was shown that the applied model was able to reproduce some essential flow features related to the bypass and wake-induced transition, and the simulations revealed good agreement with the experimental results in terms of localization and extent of wake-induced transition.

Different melatonin rhythms and sleep–wake rhythms in patients on peritoneal dialysis, daytime hemodialysis and nocturnal hemodialysis

Background Little comparative data on sleep–wake rhythms in different dialysis groups exist. The aim of this study was to investigate sleep–wake parameters measured with actigraphy and sleep questionnaires as well as melatonin rhythms in automated peritoneal dialysis, conventional daytime hemodialysis and nocturnal hemodialysis patients. Methods Conventional daytime dialysis ( n = 20), nocturnal hemodialysis ( n = 13) and automated peritoneal dialysis patients ( n = 6) were included in the study. Melatonin in saliva was sampled at 5 time points (21:00, 23:00, 1:00, 7:00 and 9:00 h). Furthermore, actigraphy measurements and sleep questionnaires were performed. All parameters were tested by Kruskall–Wallis test (followed by post hoc Dunn test) to find significant differences ( p < 0.05). Results Although most sleep parameters were impaired in all three groups, conventional daytime dialysis patients had the worst sleep. In nocturnal hemodialysis patients a normal nocturnal melatonin rise was found. In daytime hemodialysis and automated peritoneal dialysis patients this rise was absent. Conclusions The study showed impaired sleep parameters in all dialysis patient groups. As automated peritoneal dialysis is also performed during night time, the same effect on normalized melatonin was anticipated as was found in nocturnal hemodialysis. Melatonin seems to play a subordinate role in the sleep–wake rhythm of automated peritoneal dialysis patients.