Pulsating Light Research Articles

Receiving self-compassion in the virtual world: Testing the potential value of biofeedback

Self-compassion training has been shown to deliver mental health benefits and preliminary evidence suggests it might also be possible to deliver these benefits effectively via virtual reality (VR) technology. However, which features of the VR training environment influence these training benefits remains poorly understood. This study was designed to provide the first empirical test of the potential value of visual biofeedback during self-compassion training. It was theorised that the provision of biofeedback may increase the benefits of training by increasing mindfulness, a core component of self-compassion. Sixty participants were randomly allocated to one of two experimental conditions, both of which comprised VR-based self-compassion training, but only one of which included visual biofeedback (a red pulsating light representing heart rate). Relative to scores at baseline, participants reported greater self-compassion, and lower self-criticism, anxiety, and stress after VR self-compassion training. However, the provision of biofeedback did not influence the strength of these training effects. These data provide further evidence that VR administered self-compassion training may deliver potentially important mental health benefits, but also meaningfully extends this literature by proving the first evidence that visual biofeedback does not influence the strength of these benefits.

LED light can falsify pulse oximetry readings via the stroboscopic effect

Because of its simplicity, pulse oximetry plays a ubiquitous role in neonatology. Its measurements are based on the absorption of light by hemoglobin. Ambient light can affect these values, therefore algorithms are designed to compensate for constant ambient light. Modern light-emitting diodes often flicker at a very high frequency. Such flickering ambient light can lead to significant measurement errors in saturation. To present a novel way in which light-emitting diodes influence the function of pulse oximeters and to demonstrate mathematically that a stroboscopic effect may well be responsible for this disturbance. Using publicly available data, a mathematical model of a pulse oximeter with a calibration curve and a proprietary measurement algorithm was created. This was used to simulate saturation measurements in flickering ambient light. To do this, photopletysmograms for red and infrared light at 98% oxygen saturation were mathematically superimposed on the light emission from an examination lamp used in the intensive care unit. From these results, presumable saturation measurements from a pulse oximeter were extrapolated. The light-emitting diodes in the examination lamp flicker at 207 Hz. The pulsating light from the light-emitting diodes causes superimposition of the photoplethysmogram due to the stroboscopic effect. With increasing brightness, the saturation dropped to 85% and the pulse rate to 108 bpm. The pulsed light of light-emitting diodes can distort pulse oximetry measurements. The stroboscopic effect leads to low saturation values, which can lead to the risk of blindness in premature infants due to excessive oxygenation.

The influence of UV light on the course of fluorescent enzyme assays

Experiments were carried out to illustrate the effect of UV light on the course of the enzymatic reaction of the coumarin derivative. Only the pulsating light of the UV diode gives the correct results for the determination of the kinetic constants of the enzymatic reaction. The enzyme concentration limit was found where the description of the M-M model breaks. It was shown that the system determines the kinetic parameters of enzymatic reactions: Vmax —the maximum rate of reaction and KM—the Michaelis constant. This method produces kinetic constants calculated from the changes in enzyme product concentration using the Michaelis-Menten model. To verify the results, we used a statistical analysis that checks the correctness of the model used.

Conjuring the Prince Mystique

Conjuring the Prince Mystique

ANALYSIS OF THE POSSIBILITY OF USING MARKERS EMITTING PULSATING LIGHT IN THE TASK OF LOCALIZATION

This work shows the possibility of using spectral analysis in order to detect characteristic points in recorded images. The specific point is a marker in the form of a diode that flashes at a certain frequency. Main assumptions of the processing algorithm are the recording of a sequence of images and treatment change of level of brightness for each pixel as a time signal. The amplitude spectrum is determined for each time signal. The result of data processing is an amplitude image whose pixels brightness corresponding to the intensity of source of pulsating light emitting specific frequency. This new data representation is used to detect position of markers. The algorithm was re¬searched in order to select optimal marker colors and pulsation frequency. The results are described in a summary.

On the propagation modes of light bullets in the gradient fibers

An analytical study of the propagation of a spatiotemporal optical soliton in a gradient fiber with the Kerr nonlinearity has been carried out. Two approaches were used, based on the heuristic method of the averaged Lagrangian. In the framework of the first approach, for the envelope of the light signal, a well-known factorized representation is used in the form of two functions that depend on the longitudinal and transverse coordinates, respectively. In the framework of the second approach was used a trial solution in the form of temporal soliton. However, the parameters of this soliton depend on the coordinates. By means of the second approach the approximate solutions are found in the form of stationary and pulsating light bullets. The conditions for their stability are determined. These conditions apply to the aperture and temporal duration of the soliton. I addition, the soliton power should be less than a certain threshould value. If the soliton power is much less than this threshould value, then both analytical approaches are consistent with each other.

Exergy efficiency of light conversion into biomass in the macroalga Ulva sp. (Chlorophyta) cultivated under the pulsed light in a photobioreactor.

Marine macroalgae are a potential feedstock for biorefineries that can reduce dependence on fossil fuels and contribute to bioeconomy. New knowledge and technologies for efficient conversion of solar energy into macroalgae biomass are needed to increase biomass yields and energy conversion efficiency. In this work, we show that the green macroalgae from Ulva sp. can grow under the pulsed light in a photobioreactor with higher exergy conversion efficiency in comparison to cultivation under constant light with the same intensity. In the tested frequencies, 1-40 Hz and duty cycles (DC) 1-100%, DC has a stronger impact on the growth rate than frequency. The efficiency of light transformation into biomass increased with decreasing DC. Pulsating with DC 20% led to 60% of the biomass chemical energy yield for the respective constant light (DC 100%). Models of Ulva sp. growth rate and exergy conversion efficiency as a function of pulsating light parameters were developed. These results open new directions to enhance solar to chemical energy conversion through macroalgae by controlling the light distribution in the macroalgal biomass.

APPLICATION OF INTENSIVE LIGHT RADIATION IN THE PATIENT WITH ERYTHEMATOTELANGIECTATIC ROSACEA

We present a description of the clinical case of a patient with an erythematotelangiectatic type of rosacea. Rosacea is a chronic recurrent dermatosis, characterized by skin lesions of the face in the form of erythema and papulopustular elements, which has polyethological origin. The disease occurs more frequently in women aged 30-50 years who have a certain genetic predisposition to transient reddening of the skin of the face or less often of the neck and the decollete zone. It is believed that the dermatosis is more likely to affect the I and II phototypes, but the disease can occur in any skin phototype. The patient came to the clinic with complaints about rashes in the chin and nasolabial triangle, flushing of the face, accompanied by tingling and burning. The patient turned to the clinic with complaints about rashes in the chin and nasolabial triangle, flushing of the face, accompanied by tingling and burning. She never consulted a dermatologist before. A diagnosis was made: “erythematotelangiectatic type of rosacea” (according to the classification proposed by the USA National Rosacea Society, stage I — persistent erythema and telangiectasia). Using the scale of diagnostic evaluation of rosacea, it was evaluated at 12 points. There are many approaches to the treatment of rosacea. Drug therapy is divided into systemic, external and complex. Systemic therapy has a number of side effects, so for light and medium-to- severe rosacea, only external therapy is more often prescribed. Because of the presence of pathologically altered vessels, the low efficacy of metronidazole, the patient was assigned a course of phototherapy with intense incoherent pulsating light at standard parameters. There was a significant improvement after two procedures, but vessels smaller than 0.4 mm remained intact, so the duration of the first pulse was increased in order to influence small- caliber vessels. Individual selection of parameters (duration of the first impulse and fluence) was made based on the dermatoscopic picture and patient’s phototype, which resulted in a significant clinical effect and persistent remission. Using the scale of diagnostic evaluation of rosacea it was evaluated at 1 point after treatment. This clinical case demonstrates the effectiveness of phototherapy with intense incoherent pulsating light with individual selection of the duration of the first pulse and energy density in patients with erythematotelangiectatic rosacea. In IPL-treatment schemes, it is desirable to select individual parameters for the duration of the first pulse and the energy density, based on the features of the dermatoscopic picture and skin phototype of each individual patient.

PHOTOMETRIC SOLUTION AND FREQUENCY ANALYSIS OF THE oEA SYSTEM EW BOO

We present the first photometric solution and frequency analysis of the neglected oscillating Algol-type (oEA) binary EW Boo. B- and V-band light curves of the star were obtained on 11 nights in 2014. Using the Wilson–Devinney code, the eclipsing light curves were synthesized and the first photometric solution was derived for the binary system. The results reveal that EW Boo could be a semi-detached system with the less-massive secondary component filling its Roche lobe. By subtracting the eclipsing light changes from the data, we obtained the intrinsic pulsating light curves of the hotter, massive primary component. Frequency analysis of residual light shows multi-mode pulsation with the dominant period at 0.01909 days. A preliminary mode identification suggests that the star could be pulsating in non-radial (l = 1) modes. The long-term orbital period variation of the system was also investigated for the first time. An improved orbital period and new ephemerides of the eclipsing binary are given. The O−C analysis indicates a secular period increasing at a rate of dP/dt=2.9×10{sup −7} days yr{sup −1}, which could be interpreted as mass transfer from the cooler secondary to the primary component.

PHOTOMETRIC STUDY OF THE PULSATING, ECLIPSING BINARY OO DRA

We present a comprehensive photometric study of the pulsating, eclipsing binary OO Dra. Simultaneous B- and V-band photometry of the star was carried out on 14 nights. Revised orbital period and a new ephemeris were derived from the data. The first photometric solution of the binary system and the physical parameters of the component stars are determined. It reveals that OO Dra could be a detached system with the less-massive secondary component nearly filling in its Roche lobe. By subtracting the eclipsing light changes from the data, we obtained the intrinsic pulsating light curves of the hotter and massive primary component. Frequency analysis of the residuals light yields two confident pulsation modes in both B- and V-band data with the dominant frequency detected at 41.865 c/d. A brief discussion concerning the evolutionary status and the pulsation nature of the binary system is finally given.

Annual Conference, 8,000 Writers Expected

Annual Conference, 8,000 Writers Expected Rebecca McClanahan (bio) And all over America we wave goodbye to our planets of origin and climb into buzzing spaceships, each with its own pulsating light, and land on the roof of the Very Large Planet Hotel, where we disembark, unfolding ourselves from individual largeness (for the planets we have come from are so small) and descend to the Bars, to the Book Fair, to the Important Room where one Large Poet reads largely, and the pale lights of our astronaut hearts beep their applause, a little sadly, remembering our Home Planet, how different we felt there, the air clearer, our footprints grander. (Once years ago at the Large Planet Bar an Important Writer kept calling me Roberta and after I corrected him four times I knew it was time to go to bed and not with him.) Now sated with words—who knew there could be so many—we retreat heavily to our rooms, for cable. A prison flick, a Western itchy with sagebrush and cactus, a silent—ah, silent—Charlie Chaplin, his eyes rimmed with sad gaiety. Below us and above, platters rattling, bass lines thumping, meteoric laughter. My roommate sleeps soundly, she is a sound person, a sound writer, and kind. I pound the pillow and worry the lines I’ve been wrestling into verse: Did Billie Holiday’s white habit kill her or keep her alive past the pain? Is it wrong to make music from someone’s suffering? [End Page 119] Caw, caw, the insistent crow, language scraping for a song. So many songs, so many faces, names. The conference program thicker than my Home Planet’s phone directory. In my suitcase a shawl, fringed in black, and a red dress for dancing, should words fail. My roommate has packed only a bright heart that blinks for everyone, and for everyone’s books, even the slimmest volume now autographed and sliding through the crack of our hotel door just before dawn. For dawn must come, and the Book Fair’s last day, last hour: prices slashed, the violent slap and zip of packing tape. And all the minor lights flickering faintly? Send us back where we belong—to husbands and sunlight and dogs, to the News of our Home Planet, which we grasp like a shield lest we encounter on the return spaceship another weary astronaut, but wait, who is this on the Daily News cover: a Famous Poet and beautiful, too, who lost herself, hurled herself into that Vast Space where our filament lines cannot hold us aloft. Are we all hopeless, then, even the Important Writer at the bar whose singular loneliness beeps so brightly on the page? Who cares what he calls me, I’ll be Roberta, I’ll buy him a drink, whatever it takes to keep us all alive on this Planet where we can all be (ragged line breaks, almost rhymes) hopeless together, each light stuttering, the Lost One too—look, her words are still floating—there’s one now, catch it—and there’s another, sailing past our eyes. [End Page 120] Rebecca McClanahan Rebecca McClanahan has published nine books, most recently Deep Light: New and Selected Poems and The Riddle Song and Other Rememberings, a suite of essays. Her work has appeared in Best American Essays, Best American Poetry, in anthologies published by Norton, Doubleday, Putnam, and Beacon, and numerous journals. Past recipient of the Wood Prize from Poetry, the Carter Prize from Shenandoah, a Pushcart Prize in fiction, and fellowships from New York Foundation for the Arts and North Carolina Arts Council, McClanahan teaches in the low-residency MFA programs of Queens University and Rainier Writers Workshop. The Tribal Knot, a nonfiction saga, is forthcoming from Indiana University Press. Copyright © 2012 Ashland University

The semi-detached binary system IU Per and its intrinsic oscillation

We present a long-term time-resolved photometry of the short-period eclipsing binary IU Per. It confirms the intrinsic δ Scuti-like pulsation of the system reported by Kim et al. With the obtained data, an orbital period study and an eclipsing light curve synthesis based on the Wilson–Devinney method were carried out. The photometric solution reveals a semi-detached configuration with the less-massive component filling its own Roche-lobe. By subtracting the eclipsing light changes from the data, we obtained the pure pulsating light curve of the mass-accreting primary component. A Fourier analysis reveals four pulsation modes with confidence larger than 99%. A mode identification based on the results of the photometric solution was made. It suggests that the star may be in radial pulsation with a fundamental period of about 0.0628 d. A brief discussion concerning the evolutionary status and the pulsation nature is finally given.

Monochromatic phototherapy: effective treatment for grade II chronic pressure ulcers in elderly patients

Monochromatic pulsating light may have effects on wound healing. In an earlier study of grade II ulcers, there was a tendency toward better healing in the phototherapy group (p=0.06). The present study on patients with grade II ulcers was performed to verify these findings. Data from this study were pooled with data from the earlier study. Ninety-four patients were offered participation in the new study and 76 patients were evaluated. They were pooled with 87 patients from the earlier study, bringing the total to 163. All patients were treated with monochromatic pulsating light or placebo over the ulcerated area, according to a specified program up to 12 weeks. The mean normalized reduction in pressure ulcer size at week 12 was 0.79 for the phototherapy group and 0.50 for the placebo group (95% confidence interval 0.01-0.53; p=0.039). No serious side-effects were noted. Monochromatic pulsating light accelerates healing in grade II pressure ulcers in elderly patients.

Automatic classification of eclipsing binaries light curves using neural networks

In this work we present a system for the automatic classification of the light curves of eclipsing binaries. This system is based on a classification scheme that aims to separate eclipsing binary systems according to their geometrical configuration in a modified version of the traditional classification scheme. The classification is performed by a Bayesian ensemble of neural networks trained with Hipparcos data of seven different categories including eccentric binary systems and two types of pulsating light curve morphologies.

Non-invasive measurement of systolic blood pressure on the arm utilising photoplethysmography: development of the methodology

Photoplethysmography (PPG) can be used to measure systolic blood pressure at the brachial artery. With a specially designed probe, positioned in the most distal position beneath a pressure cuff on the upper arm, this is possible. The distance between the light source (880 nm) and the photodetector was 20 mm. A test was performed on neuro-intensive care patients by determining blood pressure from the PPG curves, and, when it was compared with systolic blood pressure obtained from inserted indwelling arterial catheters, a correlation factor of r = 0.95 was achieved. The difference between blood pressure obtained using PPG and invasive blood pressure measurement was 3.9 +/- 9.1 mmHg (mean +/- SD), n = 19. The depth to the brachial artery was 13.9 +/- 4.1 mm (mean +/- SD), n = 18. A digital PPG system utilising pulsating light was also developed.

Multiband photometric re-classification of ROTSE-IδScuti type stars

We present multi-passband CCD photometry of 20 ROTSE-I Scuti type pulsating stars and 1 RR Lyrae star to re- classify their variable types using the comparison of amplitudes between V and I passbands. For the re-classification, we used a criterion that pulsating stars have larger amplitude dierences between passbands than eclipsing binaries because brightness changes of pulsating stars are mainly due to the temperature variations. As a result, only six stars were re-confirmed as Scuti variables and thirteen stars turned out to be W UMa type eclipsing binaries. The other two stars were identified as one cataclysmic variable and one non-variable, respectively. Our results suggest that a number of ROTSE-I Scuti type stars, which do not show typical pulsating light curves of high amplitude Scuti stars, are W UMa type eclipsing binaries.

Prenatal experience and postnatal perceptual preferences: evidence for attentional-bias in bobwhite quail embryos (Colinus virginianus).

Previous studies have indicated that concurrent multimodal sensory stimulation can interfere with prenatal perceptual learning. This study further examined this issue by exposing 3 groups of bobwhite quail embryos (Colinus virginianus) to (a) no supplemental stimulation, (b) a bobwhite maternal call, or (c) a maternal call paired with a pulsating light in the period prior to hatching. Experiments differed in terms of the types of stimuli presented during postnatal preference tests. Embryos receiving no supplemental stimulation showed no preference between stimulus events in all testing conditions. Embryos receiving exposure to the unimodal maternal call preferred the familiar call over an unfamiliar call regardless of the presence or absence of pulsating light during testing. Embryos exposed to the call-light compound preferred the familiar call only when it was paired with the light during testing. These results suggest that concurrent multimodal stimulation does not interfere with prenatal perceptual learning by overwhelming the young organism's limited attentional capacities. Rather, multimodal stimulation biases what information is attended to during exposure and subsequent testing.

Continuous noninvasive measurement of cerebral arterial and venous oxygen saturation at the bedside in mechanically ventilated neonates.

To test the practicablity of a new spectrophotometric method using pulse oximetric techniques in combination with special filters for the noninvasive determination of cerebral arterial and venous oxygen saturation and oxygen extraction in neonatal intensive care unit patients. The spectrophotometer used three different wavelengths at a sampling rate of 100 Hz. Clinical evaluation of a new method and comparison with previously published data. Design and construction of the special spectrophotometer at the Biomedical Engineering Laboratory of the Swiss Federal Institute of Technology. Measurements in the neonatal intensive care unit of the University Hospital, Zurich, Switzerland. Convenience sample of 15 clinically stable newborn infants, who were mechanically ventilated and receiving supplemental oxygen. Median gestational age was 29 5/7 wks (range 26 3/ 7 to 36 0/7), median birth weight was 1555 g (720 to 2500), median postnatal age was 4 days (1 to 10). The emitter and receiver were placed on the forehead near the sagittal sinus, between 2 and 2.8 cm apart, and the pulsating light attenuations (arterial and venous pulse waves) were recorded. Arterial and venous pulse waves were satisfactory in 10 of 15 infants. Mean cerebral arterial oxygen saturation was 89.9 +/- 5.4% (SD), mean cerebral venous oxygen saturation was 73.0 +/- 8.9%, and mean cerebral oxygen extraction was 16.9 +/- 11.7%. A linear regression analysis demonstrated a significant correlation between mean PCO2 and venous oxygen saturation (slope 1.0%/torr, p < .05) and between mean PCO2 and cerebral oxygen extraction (slope -1.3%/torr, p < .05). This new method has the potential for monitoring continuously, noninvasively, and simultaneously cerebral arterial and venous oxygen saturation and oxygen extraction in mechanically ventilated preterm infants.

Contrast Reversal of Magneto-Optical Domain Image by Photo-Elastic Modulator

Two methods were employed to study the fast contrast reversal of magnetic domain images by a photoelastic modulator (PEM). A PEM combined with a quarter-wave plate acts as a polarization rotator, and enables domain observation with fast contrast reversal under exposure to pulsating light. Contrast reversal in as little as 10 ?s is possible. However, the PEM is driven sinusoidally, hence the domain contrast is modulated, resulting in a low average contrast. When a PEM was employed as a phase compensator with a garnet film polarization rotator, it could dynamically compensate for unwanted contributions from the ellipticity of the sample and the garnet rotator. This combination provided not only fast contrast reversal, but even higher contrast compared with that obtained in conventional methods involving the mechanical rotation of an analyzer. In the latter method, a domain image contrast of 0.82 was derived theoretically, and a contrast of 0.76 was obtained experimentally, for domains with ? k =0.19° and ? k =0.13°, whereas the contrast using the conventional mechanical method was 0.72.

光弾性素子を用いた磁気光学磁区像のコントラスト反転

Two methods were employed to study the fast contrast reversal of magnetic domain images by a photoelastic modulator (PEM). A PEM combined with a quarter-wave plate acts as a polarization rotator, and enables domain observation with fast contrast reversal under exposure to pulsating light. Contrast reversal in as little as 10 ?s is possible. However, the PEM is driven sinusoidally, hence the domain contrast is modulated, resulting in a low average contrast. When a PEM was employed as a phase compensator with a garnet film polarization rotator, it could dynamically compensate for unwanted contributions from the ellipticity of the sample and the garnet rotator. This combination provided not only fast contrast reversal, but even higher contrast compared with that obtained in conventional methods involving the mechanical rotation of an analyzer. In the latter method, a domain image contrast of 0.82 was derived theoretically, and a contrast of 0.76 was obtained experimentally, for domains with ? k =0.19° and ? k =0.13°, whereas the contrast using the conventional mechanical method was 0.72.