Wake Function Research Articles

DSIP in sleep disturbances.

The effects of DSIP on night sleep and on waking functions are demonstrated in double-blind studies in insomniacs, presenting influences of single dose treatments as well as of repeated injections. Moreover, a single case study describes the efficiency of DSIP on narcolepsy.

Daytime alertness in subjective and objective insomnia: Some preliminary findings

Daytime performance and alertness were examined in two groups of patients with disorders of initiating and maintaining sleep (DIMS) and a control group of self-described good sleepers. Individuals complaining of disturbed sleep that was verified by polysomnographic indices (objective DIMS) and a group with complaints of disturbed sleep in the absence of objective findings (subjective DIMS) were compared with normal sleepers. Nocturnal polysomnographic recordings documented increased sleep latencies and decreased sleep efficiencies for the objective DIMS group and essentially normal sleep for the subjective DIMS group. However, the subjective DIMS group showed impaired daytime vigilance compared with both the objective DIMS and control groups. Additionally, the subjective DIMS group demonstrated an atypical daytime alertness and a tendency toward lowered arousal during vigilance task performance. Insomniacs without clear objective findings of disturbed sleep, therefore, showed decrements commonly seen following sleep loss or sleep disturbance, whereas insomniacs with evidence of disturbed nocturnal sleep did not differ from the control group in terms of waking function.

Suspended Sediment Effect on Flow Resistance

A general velocity distribution consisting of a logarithmic profile plus a wake function has been used to investigate the effect of suspended sediment on flow resistance. From the experimental evidence that the wake constant increases when sediment is in suspension, it is shown that flow resistance must be reduced. It is shown that a flow with suspended sediments should have lower velocities near the boundary and higher velocities further away from the boundary than a clear water flow, given that the discharge and slope are identical.

EEG sleep in outpatients with generalized anxiety: A preliminary comparison with depressed outpatients

To develop further perspective on the psychophysiology of generalized anxiety disorder and primary depression, all-night electroencephalographic (EEG) sleep measures in outpatients with diagnoses of generalized anxiety disorder and primary (nondelusional) depression were compared. Both groups had difficulty initiating and maintaining sleep, and diminished amounts of slow-wave sleep. Compared to patients with generalized anxiety disorder, depressive had a shorter rapid eye movement (REM) latency, greater REM sleep percent and eye movement activity, and a different temporal distribution of REM sleep. Anxious patients showed few changes from first to second night, whereas depressives showed increases in several REM sleep indexes. The combination of REM sleep latency and REM percent correctly classified 86.7% of patients. These data may provide a more direct measure of central nervous system arousal and sleep / wake function than previous studies in the psychophysiology of anxiety. They also lend support to the clinical distinction between generalized anxiety disorder and primary depression and to the classification of anxiety states as disorders of initiating and maintaining sleep.

Evaluation of temazepam as a hypnotic

Temazepam is a 1,4-benzodiazepine, newly marketed in the United States for the symptomatic treatment of the complaint of insomnia. The manufacturer recommends a dose of 30 mg before bedtime for most adults and 15 mg for geriatric or debilitated patients. A dose of 30 mg usually produces peak plasma concentrations within 3 hours after oral ingestion and has a mean half-life of 10 to 15 hours. Thus, temazepam is absorbed more slowly and metabolized more quickly than flurazepam, the only other benzodiazepine marketed in the United States specifically for insomnia. Eight sleep laboratory and 21 clinical studies on temazepam indicate that temazepam reduces awakening during the night and increases sleep duration. However, there was no consistent evidence that temazepam reduces sleep latency--probably because temazepam, taken at bedtime, does not reach sufficiently high blood levels in time to affect sleep onset. One sleep laboratory study on 8 insomniac patients given 35 consecutive nightly doses of 30 mg found no evidence of tolerance or rebound insomnia. Studies on tolerance, metabolism and carry-over effects have shown that temazepam has no long-acting metabolites and does not affect waking function following use at bedtime. In patients for whom hypnotic medication is appropriate, temazepam should be an effective drug for reducing most symptoms of insomnia.

Effects of scheduled afternoon naps and bedrest on daytime alertness

A forced-rest postulate and recuperative theory of sleep function were tested. Eighteen normal, healthy young adult males were studied in a balanced design which comprised single treatment replicates of polygraphically recorded 2:40-4:00 p.m. napping and bedrest. Under both conditions subjects were required to lie quietly in bed with eyes closed. During bedrest, stage 1 sleep episodes were allowed to intervene, but for no longer than 1.5 min simultaneously. Dependent variables of waking function were initially assessed at 12:30 p.m. for 1.2 hr and then again 20 min following the conditions from 4:20 until 5:30 p.m. Measurements were obtained from: (a) short-term memory, visual four-choice reaction time, and auditory vigilance tasks; (b) 4-7 Hz EEG theta rhythm; (c) sublingual temperature; (d) the Stanford Sleepiness Scale; and (e) mood subscales (activation, euphoria, fatigue) on an adjective check list. During bedrest compared with napping, subjects averaged significantly more: (a) stage 1 (in aggregate:...

Evaluation of temazepam as a hypnotic.

Temazepam is a 1,4-benzodiazepine, newly marketed in the United States for the symptomatic treatment of the complaint of insomnia. The manufacturer recommends a dose of 30 mg before bedtime for most adults and 15 mg for geriatric or debilitated patients. A dose of 30 mg usually produces peak plasma concentrations within 3 hours after oral ingestion and has a mean half-life of 10 to 15 hours. Thus, temazepam is absorbed more slowly and metabolized more quickly than flurazepam, the only other benzodiazepine marketed in the United States specifically for insomnia. Eight sleep laboratory and 21 clinical studies on temazepam indicate that temazepam reduces awakening during the night and increases sleep duration. However, there was no consistent evidence that temazepam reduces sleep latency--probably because temazepam, taken at bedtime, does not reach sufficiently high blood levels in time to affect sleep onset. One sleep laboratory study on 8 insomniac patients given 35 consecutive nightly doses of 30 mg found no evidence of tolerance or rebound insomnia. Studies on tolerance, metabolism and carry-over effects have shown that temazepam has no long-acting metabolites and does not affect waking function following use at bedtime. In patients for whom hypnotic medication is appropriate, temazepam should be an effective drug for reducing most symptoms of insomnia.

A Computer Simulation of Longitudinal Single-Bunch Effects in Electron-Positron Storage Rings

The computer code TRACK simulates longitudinal single-bunch effects in an electron-positron storage ring. The program tracks the turn-by-turn energy and phase deviations of N superparticles, where N is 100-1000. In addition to the usual RF and lattice parameters, an input to the program is the wake potential function for the ring vacuum chamber. The program has been applied to compute bunch lengthening in SPEAR as a function of charge per bunch. Although the computed results are in qualitative agreement with measurements, there are discrepancies in some details. Possible reasons for these discrepancies are discussed.

Some Experiments on Artificially Roughened Lucy Ashton Geosims

A mirror-image model of the Lucy Ashton was covered with two different "mesh-type" roughnesses and tested in a wind tunnel. Total drag and velocity profile measurements are presented. Total drag results are also given for a normal Lucy Ashton model with the same roughness mesh tested in a towing tank. The influence of roughness on the wave drag component was found to be small, implying that the "interdependence" of wavemaking and viscous resistance is small. The importance of considering roughness as a local parameter is demonstrated, and the roughness function results agree well with the fully developed turbulent pipe flow results of Perry and Abell, even though the ship boundary-layer outer flow did not follow any recognized wake function.

Organization of somatosensory receptive fields in cortical areas 7b, retroinsula, postauditory and granular insula of M. fascicularis

The boundaries of the second somatic sensory cortex (SII) in primates are difficult to define physiologically because cutaneous stimulation activates several regions around SII that do not receive projections from the ventroposterior nucleus of the thalamus. These cortical regions, which include portions of area 7b, the retroinsular (Ri) and postauditory fields (PA), and the granular insula (Ig) are largely buried within the lateral sulcus and most lie posterior to the caudal end of the insula. The differences in somatic activity in these various cortical fields in the unanesthetized cynomolgus monkey became apparent only after the properties of many neighboring neurons could be compared. Receptive fields for area 7b and Ig neurons were generally large (< 10 cm2), with bilateral, moderately defined boundaries; some neurons in area 7b had receptive fields with labile borders as a function of wakefulness. In contrast, receptive fields for Ri neurons were generally (< 10 cm2 and contralateral, with stable, well-defined boundaries. Taken as an ensemble, the neurons in areas neighboring SII exhibited a very crude topography; but at the level of an individual neuron and its neighbor, there was never a pattern of gradual transition in peripheral receptive field locations between one unit and the next, like that seen in SII. In area 7b, this crude map was organized mediolaterally across the inferior parietal lobule and into the upper bank of the lateral sulcus, with the head represented medially and the lower trunk and hindlimb laterally. In Ri-PA, an anteroposterior organization was noted along the fundus of the lateral sulcus with the head represented anterior to the lower trunk and hindlimb. No organization was apparent in Ig. Additional sensitivity to visual stimuli was noted in the more medial aspects of area 7b that were located on the exposed inferior parietal lobule. Sensitivity to auditory stimuli was principally found in PA and occasionally in Ri. The results, especially from area 7b, are discussed with respect to previous notions about the organization of SII.

Diverging and Converging Flows of Dilute Polymer Solutions : 2nd Report, Universal Velocity Profile of Turbulent Diverging Flow

Velocity profiles of a turbulent diverging flow are formulated by using a wake function. the frictional coefficient, the stress distributions and the mixing length are calculated by an empirical equation, which includes the result of Newtonian fluids. In a Newtonian flow, the frictional coefficient decreases when the fluid flows in downstream direction because of the inverse pressure gradient. Then, the position of the maximum stress shifts to the center from the wall, and the polymer additives promote this tendency. when the pressure gradient is small, the mixing length of a diverging flow is decreased by the addition of polymers, but it is increased when the pressure gradient is large.

Wall pressure spectra calculations for equilibrium boundary layers

Assuming information about the mean velocity and vertical turbulent velocity, it is possible to calculate the flow direction wavenumber spectrum of pressure fluctuations ϕ(k1 δ)/τ02δ. The law of the wall plus Cole's wake function represented the mean velocity profiles. A scale-anisotropic model of R22 was used and the component intensity û2 was assumed to vary across the boundary layer in constant proportionality to the Reynolds stress. Calculated zero-pressure-gradient spectra rise as k11.5 at low wavenumbers. Curves for various Reynolds numbers are closely similar, and diverge only slightly around the peak in the spectrum. A high wavenumber spectrum ϕk1v/u*. u*/τ02v is independent of Reynolds number. The calculations reveal an overlap region in which ϕ ∼ k1−1. Imposing an equilibrium pressure gradient increases the spectrum at the low and mid wavenumbers, but has no effect in the overlap region. The spectrum peak for II = 6 is a factor 102 higher than for the zero-pressure-gradient layer. It is proposed that the convective velocity Uc(k1) has an overlap region. The overlap law is found to be \[ \frac{U_c}{u_{*}} = -\frac{1}{\kappa}\ln k_1\delta +\frac{1}{\kappa}\ln\frac{u_{*}\delta}{\nu}+A, \] where K and A are the same constants as in the mean velocity expression. Comparison with experiments shows very good agreement. A rough convective ‘wake’ function is formulated for the low-wavenumber range. Wavenumber spectra are converted to frequency spectra, and compared with experiments. Data from a zero pressure gradient and an adverse pressure gradient II = 3 show reasonable agreement with the calculations.

Turbulent boundary layers with negligible wall stress: A singular-perturbation theory

Abstract A singular-perturbation theory of turbulent boundary layers with negligible wall stress is developed. In the limit as the Reynolds number approaches infinity, viscous effects become negligible in the first-order description of these boundary layers. A single-layer model thus is adequate to first-order. It is found that Cole's wake function, W ( y / δ ), corresponds to the first-order velocity profile. The second-order theory is based on a two-layer model. The second-order inner layer employs Tennekes' viscosity-pressure velocity u s , as the velocity scale and v / u s as the length scale. The second-order outer layer is a velocity-defect layer, which utilizes u s as the velocity scale and δ as the length scale. The second-order theory leads to a second-order ‘friction’ law and to a second-order correction to the asymptotic distribution of pressure and boundary-layer thickness. A comparison between Stratford's experimental data and the results of the theory indicates a satisfactory agreement.

Effects of auditory stimulation on heart rate in premature infants as a function of level of arousal, probability of CNS damage, and conceptional age.

AbstractIn 2 experiments, heart rate responses of newborn infants to an auditory stimulus as a function of sleep vs wakefulness, probability of perinatal impairment of the central nervous system, and developmental level were compared. All subjects were studied under standard conditions, in their own incubators, using an 80 dB (re 0.02 dynes/cm2) low‐frequency buzzer of 3‐sec duration. Heart rate responses were averaged over 10 trials for each subject in each state. In the first study, which compared the responses of high‐ and low‐risk subjects of 1800 gm or greater weight, it was found that there was no difference between the groups in the response during sleep; or greater weight, it was found that there was no difference between the groups in the response during sleep; during wakefulness, however, a significant difference in the direction of response was found. High‐risk subjects accelerated, as in sleep, whereas low‐risk subjects decelerated. In a developmental study of 4 small premature infants, it was found that the direction of the waking heart rate response changed from acceleration to deceleration at about 35 to 36 weeks conceptional age.

Experiments on a turbulent cylindrical wall jet

The investigation described here is an experimental study directed toward determining flow field and surface friction characteristics of a cylindrical wall jet. The flow configuration is obtained by placing a cylindrical rod along the axis of a converging nozzle. The flow field thus produced consists of a developing turbulent boundary layer co-existing with an outer fluid layer that mixes freely with quiescent surroundings. Direct measurements of fluid friction at the rod surface, performed with a hot-film element, revealed a significant effect of transverse surface curvature on the local friction factor. Velocity profiles at various axial stations exhibited similarity in the outer mixing layer, but not in the boundary layer adjacent to the surface. Representations of the velocity field in terms of law of the wall variables and defect-law variables revealed significant transverse curvature effects. The measured wall-jet velocity profiles could be satisfactorily represented in terms of a law of the wake, wherein the wake function depends on a transverse curvature parameter. In the outer mixing layer, the eddy viscosity data correspond closely to those of free jets.

The Three-Dimensional Turbulent Boundary Layer

An experimental verification of coles’ postulate of the Law of the Wake in three dimensions has been attempted. This hypothesis, which is strongly supported by experimental evidence in two dimensions, purports to represent the velocity vector in a yawed boundary layer by the sum of two vectors, whose magnitudes are found from the universal law of the wall, and a second universal function, the law of the wake. It has been found that the velocity vector can be represented in this way and the wake function required for this is very similar to Coles’ form. Limitations of the experimental arrangement however prohibited the comparison of vector directions with that proposed by Coles.