Low Intensity Levels Research Articles

Tele-connection of global crude oil network: Comparisons between direct trade and embodied flows

Crude oil is one of the most widely used energy sources and the most important commodities in the global economy. To illustrate the gap between crude oil trade and consumption, this study calculated the internal intensity of global crude oil tele-connection, compared the differences of topological structures, and tested the energy risks between the direct oil trade network and embodied oil transfer network. Based on the results, evident differences were identified between the direct trade network and embodied transfer network. The direct trade network had less relational links but a higher internal intensity level, while the embodied oil transfer network had more relational links but a lower internal intensity level. For the regional components, the crude-oil-rich and highly industrialized countries/regions occupied the core circle in the direct oil trade network, whereas the highly industrialized countries/regions occupied the core position in the embodied oil transfer network. When tested, node countries in the core circle of the trade network were less sensitive under deliberate attack, but the direct oil trade network was easier to collapse than the embodied transfer network. With the comparisons between direct trade and embodied transfers, this work provides a more systematic perspective on the tele-connected crude oil networks.

Land-use intensity alters networks between biodiversity, ecosystem functions, and services

Land-use intensification can increase provisioning ecosystem services, such as food and timber production, but it also drives changes in ecosystem functioning and biodiversity loss, which may ultimately compromise human wellbeing. To understand how changes in land-use intensity affect the relationships between biodiversity, ecosystem functions, and services, we built networks from correlations between the species richness of 16 trophic groups, 10 ecosystem functions, and 15 ecosystem services. We evaluated how the properties of these networks varied across land-use intensity gradients for 150 forests and 150 grasslands. Land-use intensity significantly affected network structure in both habitats. Changes in connectance were larger in forests, while changes in modularity and evenness were more evident in grasslands. Our results show that increasing land-use intensity leads to more homogeneous networks with less integration within modules in both habitats, driven by the belowground compartment in grasslands, while forest responses to land management were more complex. Land-use intensity strongly altered hub identity and module composition in both habitats, showing that the positive correlations of provisioning services with biodiversity and ecosystem functions found at low land-use intensity levels, decline at higher intensity levels. Our approach provides a comprehensive view of the relationships between multiple components of biodiversity, ecosystem functions, and ecosystem services and how they respond to land use. This can be used to identify overall changes in the ecosystem, to derive mechanistic hypotheses, and it can be readily applied to further global change drivers.

Relation of exercise and pain in patients with idiopathic distal axonal polyneuropathies.

Although exercise is associated with better outcomes in patients with some peripheral neuropathies, data in idiopathic peripheral neuropathies is lacking. This study was completed to do a comprehensive data analysis about the benefits of regular exercise in a well-characterized cohort of patients with idiopathic distal, symmetrical, axonal polyneuropathy enrolled in the Peripheral Neuropathy Research Registry (PNRR) at Johns Hopkins University School of Medicine. From the patient-reported exercise habits, metabolic equivalents (METs) were calculated and the patient information was grouped into four categories. The PNRR data set, including patient reported pain, numbness, and weakness, was analyzed using the METs categories to evaluate for the benefits of exercise. We controlled for the components of metabolic syndrome including Hemoglobin A1c (HbA1c), systolic and diastolic blood pressure (BP), high density lipids (HDL) and triglyceride level, and body mass index (BMI) as defined by the Adult Treatment Panel III Guidelines. Lower METs were associated with neuropathic pain, but not with other peripheral neuropathy symptoms. Patients with IPN who exercised were less likely to have painful neuropathy independent of the average METs per week (P < .01). No significant differences were seen for patient reported numbness, weakness, or balance issues. The data suggests that patients with idiopathic neuropathy benefit from exercises even if performed on a low intensity level or less frequently, and patients are less likely to have severe pain symptoms when exercising on a regular basis.

Validity of skin blot examination for albumin and nerve growth factor β to detect itching of the skin in Indonesian older adults

AimItching, a common skin disorder, impacts the quality of life of individuals. Itchy skin occurs more with increasing age and the prediction of itchy skin prognosis is necessary to provide good skincare. This study validated biomarkers in skin blotting to identify and measure itching sensation as well as conventional methods to measure skin barrier function. Materials and methodsFrom a cross-sectional study conducted in Long-term Care (LTC) facilities in Indonesia itching symptoms were obtained through a questionnaire. Skin conditions were assessed using photographs, stratum corneum (SC) hydration, skin pH, and skin blotting for biomarkers: albumin, interleukin 2 (IL2), nerve growth factor β (NGFβ), and thymic stromal lymphopoietin (TSLP). Association of skin measurements with the presence of skin blotting and trends analysis were conducted. ResultsAltogether, 564 LTC residents (average age, 70 years) participated. The SC hydration, skin pH, albumin, and NGFβ were associated with the presence of itch (p value= <0.001, <0.001, <0.001, and <0.001, respectively). The signal levels of skin blotting biomarkers were higher in itch group than in the non-itch group. Additionally, the higher quantile of SC hydration was significantly associated with a lower intensity level of NGFβ and TSLP (p value = 0.005, 0.003, respectively). The lower quantile of skin pH (better skin condition) was significantly associated with lower albumin, NGFβ, and TSLP (p value = 0.048, 0.035, and <0.001, respectively). ConclusionThe albumin, NGFβ, and TSLP could be a candidate for measurement of itchy skin among older adult with disrupted skin barrier function and local skin inflammation.

Comparison of Development Mechanisms of Two Cyclones Affecting Northeast China

Two cyclones (C304 and C502) generated in the Jianghuai Basin on 3-5 March 2007 and 2-3 May 2016, affect the northeast region in a similar way. However, their intensities are different. The development of C304 is strong whereas that of C502 is explosive. Based on NCEP FNL analysis data and conventional data, their development dynamics are comparatively analyzed, through diagnosis of vorticity advection, temperature advection, moist potential vorticity and frontogenesis function, combining with the circulations of high and low altitudes. The result shows that the vorticity factor and thermal factor play roles in deepening cyclone development and guiding cyclone movement. There are strong cold and warm temperature advections at low attitudes in the process of the strong evolution of C304. High-level positive vorticity advection located above the ground cyclone provides high-level divergence field. During the explosive development of C502, cold and warm advections are inconspicuous. Highly positive vorticity advection is located in front of the high-attitude trough. The development of high-level closed circulation is promoted by the high-level positive vorticity advection. As for C304, strong frontogenesis and frontolyzes symmetrically develop on the lower troposphere, whereas the baroclinicity of C502 is inconspicuous. Positive moist potential vorticities strongly develop in the upper and lower troposphere unusually. C304 vorticity increases mainly in the lower troposphere, however, C502 vorticity increases mainly in the upper troposphere where the high-humidity vortex tongue develops drooping and merges with the troposphere below the positive wet-position vortex column. Two cyclones develop with coexistence of two high-level jets, non-latitude jet and the anticyclonic curved circulation. Southerly and northerly airflows are established in the background of the cyclonic circulation at 850 hPa. C304 is located on the left front of the southerly airstream, and C502 is located between the southerly and northerly airstreams. Under the effect of low-level intensity convergence and high-level intensity scattering, the vertical ascent motion of C304 increases in lower to upper middle troposphere above the ground cyclone center. Under the strong high-level intensity scattering and weak low-level convergence, the vertical ascent movement of C502 occurs on both sides of the ground cyclone center and middle troposphere. Low-level baroclinic forcing is the main starting development mechanism of C304, and high-level vortex downward transmission is the main mechanism of C502 development.

A Study of Noise Impact on the Stability of Electrostatic MEMS

Abstract Noise-induced motions are a significant source of uncertainty in the response of micro-electromechanical systems (MEMS). This is particularly the case for electrostatic MEMS where electrical and mechanical sources contribute to noise and can result in sudden and drastic loss of stability. This paper investigates the effects of noise processes on the stability of electrostatic MEMS via a lumped-mass model that accounts for uncertainty in mass, mechanical restoring force, bias voltage, and AC voltage amplitude. We evaluated the stationary probability density function (PDF) of the resonator response and its basins of attraction in the presence noise and compared them to that those obtained under deterministic excitations only. We found that the presence of noise was most significant in the vicinity of resonance. Even low noise intensity levels caused stochastic jumps between co-existing orbits away from bifurcation points. Moderate noise intensity levels were found to destroy the basins of attraction of the larger orbits. Higher noise intensity levels were found to destroy the basins of attraction of smaller orbits, dominate the dynamic response, and occasionally lead to pull-in. The probabilities of pull-in of the resonator under different noise intensity level are calculated, which are sensitive to the initial conditions.

Colorimetric Diagnostic Capillary Enabled by Size Sieving in a Porous Hydrogel.

Handy and disposable point-of-care diagnostics facilitate the early screening of severe diseases in resource-limited areas. To address urgent needs in inconvenient sites, a simple colorimetric diagnostic device equipped with a capillary tube with porous hydrogel and immunocomplex particles was developed for the rapid detection of biomarkers (16 min). In this device, probe particles attach to capture particles (dp = 40 µm) and form sandwiched immunocomplexes in the presence of target biomarkers, and a red color progressively emerges when the sandwiched immunocomplex particles are blocked by the porous hydrogel embedded inside the glass capillary. Colorimetric aggregation was recorded using a smartphone and analyzed with imaging software. The limit of detection reached 1 ng/mL and showed a maximum of 79% accuracy compared with that obtained through a conventional spectrophotometric technique. The level of a diabetic retinopathy (DR) biomarker, lipocalin-1 (LCN-1), was measured in 1 µL of a human tear sample and used in testing the practicability of the proposed device. All healthy subjects showed lower intensity levels than the other diabetic counterparts (proliferative DR or nonproliferative DR patients), implying the potential of this device in clinical applications. Overall, the diagnostic device facilitates point-of-care-testing and provides a low-cost (~1 USD), compact, and reliable tool for early diagnosis in resource-limited areas.

Timed physical exercise does not influence circadian rhythms and glucose tolerance in rotating night shift workers: The EuRhythDia study

Objectives:Night shift workers are at cardiometabolic risk due to circadian misalignment. We investigated whether infrequent exercise before each night shift that intentionally would not improve physical performance improves glucose tolerance and 24-h blood pressure profiles and synchronizes circadian rhythms of melatonin and cortisol in rotating night shift workers.Methods:A total of 24 rotating night shift workers (mean age, 35.7 ± 11.8 years) were randomized to exercise or no intervention. Workers in the exercise group performed 15.2 ± 4.5 exercise sessions within 2 h before each night shift. Before and after 12 weeks of exercise intervention and 12 weeks after the intervention, spiroergometry, oral glucose tolerance testing and 24-h blood pressure profiles were performed. Plasma melatonin and cortisol levels were measured in 3-hourly intervals during one 24-h period on each study day.Results:Exercise did not significantly change serum glucose nor insulin levels during oral glucose tolerance testing. Timed physical exercise had no effect on physical performance, nor did it change the circadian rhythms of melatonin and cortisol or influence 24-h blood pressure profiles.Conclusion:Physical exercise before each night shift at a low intensity level that does not improve physical performance does not affect circadian timing, glucose tolerance or 24-h blood pressure profiles in rotating night shift workers.

Automatic Segmentation of Dental Cone Beam Computed Tomography Image Based on Level Set Method Using Morphology Operators and Polynomial Fitting

Abstract Automatic Segmentation of dental cone beam computed tomography (CBCT) images is challenging due to the intensity of the teeth that have low level intensity. In this paper we proposes a new method for automatic teeth segmentation in slices of CBCT images based on level let method using morphology operators and polynomial fitting. Morphology operators are used to construct the Region of Interest (ROI) area of dental objects in the image slice. ROI is used to focus the analysis process on areas of dental objects which generally have a polynomial pattern distribution. Polynomial fitting is obtained to estimation arc of teeth structure in CBCT images. Level Set is implemented to evolve the ROI to obtain the contours of dental objects. Comparison between proposed method result and the ground truth images shows that the method gives best average accuracy, sensitivity, and specificity value of 99.02%, 95.32%, 99.09%, respectively. This value that the proposed method is promising for accurate segmentation of the entire tooth form on CBCT images.

Quantum-inspired detection for spectral domain optical coherence tomography.

Intensity levels allowed by safety standards (ICNIRP or ANSI) limit the amount of light that can be used in a clinical setting to image highly scattering or absorptive tissues with optical coherence tomography (OCT). To achieve high-sensitivity imaging at low intensity levels, we adapt a detection scheme-which is used in quantum optics for providing information about spectral correlations of photons-into a standard spectral domain OCT system. This detection scheme is based on the concept of dispersive Fourier transformation, where a fiber introduces a wavelength-dependent time delay measured by a single-pixel detector, usually a high-speed photoreceiver. Here, we use a fast superconducting single-photon detector SSPD as a single-pixel detector and obtain images of a glass stack and a slice of onion at the intensity levels of the order of 10 pW. We also provide a formula for a depth-dependent sensitivity falloff in such a detection scheme, which can be treated as a temporal equivalent of diffraction-grating-based spectrometers.

Dynamics of microorganism cultivation with delay and stochastic perturbation

In the microorganism cultivation process, delay and stochastic perturbations are inevitably accompanied, which results in complicated dynamical behaviors for microorganisms. In this paper, a mathematical model with discrete delay and random perturbation is constructed to understand how the dynamics of microorganisms in the turbidostat can be characterized. The existence, uniqueness and boundedness of the positive solution are first determined for the mathematical model. Furthermore, sufficient conditions for microorganism extinction and permanence in the turbidostat are obtained with the theory of stochastic differential equations. The system has the stationary distribution under a low-level intensity of stochastic perturbation from the environment; that is, microorganism in the turbidostat is persistent fluctuating around a positive value. On the contrary, microorganisms will be extinct with a strong enough intensity of noise. Several numerical simulations are applied to validate the theoretical results for the dynamics of the system.

846-P: Improvement in Glucose Metabolism with Four Weeks of Neuromuscular Electrical Stimulation in Sedentary Adults

Most U.S. adults do not meet minimum exercise recommendations by ACSM. We and others have shown an increase in GLUT4 protein and glucose uptake with electrical stimulation induced muscle contraction using an in vitro cell culture model. However, effectiveness of neuromuscular electrical stimulation (NMES) in humans to improve insulin sensitivity is not clear. Purpose: To determine the effects of four weeks of NMES on insulin sensitivity, substrate utilization, and muscle mass in sedentary humans. Methods: Sedentary overweight/obese subjects (n=10; Age 36.8 ±3.8 yrs; BMI 32.0 ±1.3 kg/m2) were randomized into a control (Con) or NMES group. All participants received bilateral quadriceps stimulation (3x/wk; 30 min/ses) either at low intensity sensory level (Con) or high intensity neuromuscular level (NMES) for 4 weeks (50Hz). Insulin sensitivity was assessed by oral glucose tolerance test (OGTT), substrate utilization by indirect calorimetry, blood lactate by lactate analyzer, and body composition by DXA. Results: Con and NMES groups had comparable fasting blood glucose, glucose tolerance, substrate utilization, and muscle mass (all p&amp;gt;0.05) at baseline. Four weeks of NMES tended to improve glucose tolerance, measured by glucose area under the curve (AUC) (455.6 ±26.1 to 415.4 ±25.9 AU; p=0.07) whereas no change was observed in Con (430.7 ±20.2 to 494.7 ±77.2 AU; p=0.76). Glucose level after 2 hours of glucose consumption during OGTT was significantly lower after 4 weeks of NMES (150.9 ±7.6 to 138.2 ±7.6 mg/dL; p=0.03) whereas no change was observed in Con (151.8 ±6.1 to 173.2 ±34.2 mg/dL; p=0.33).Additionally, lactate AUC assessed during 30 min of NMES, was significantly greater compared to that of Con (p&amp;lt;0.02). There was no change in substrate utilization (p=0.85) or muscle mass (p=0.17) after NMES intervention. Conclusion: NMES is a novel and effective strategy to improve insulin sensitivity and glucose utilization in an at-risk overweight/obese sedentary population. Disclosure S. Bajpeyi: None. M. Galvan: None. M.J. Sanchez: None. J.B. Boyle: None. K. Min: None. F.J. Agullo: None. J.D. Covington: None. Funding University of Texas at El Paso

Torsional irregularity indices for the seismic demand assessment of RC moment resisting frame buildings

Design standards across the world use different parameters to quantify degree of torsional irregularity of buildings. Popular among such descriptors are the normalized static eccentricity ratio, torsional radius to mass radius of gyration ratio, maximum to minimum (or average) elastic floor displacement ratio, etc. However prior research, particularly on idealized single storey systems have indicated that these parameters do not correlate well with the seismic demands at all stages of structural behaviour (i.e. elastic and inelastic). The present study aims to identify a robust torsional irregularity index that captures the susceptibility of a structure to torsional effects at all ground motion intensity levels. To this end, the correlation between the maximum interstorey drift demands and popular torsional irregularity descriptors is first examined under different intensities of ground shaking using an approach that integrates multiple stripe analysis and statistical regression analysis. The numerical study is based on the nonlinear seismic assessment of thirteen three-storey gravity designed RC moment frame buildings subjected to bidirectional seismic excitation. The results indicate that none of the scalar indices considered correlate well with the drift demands at all intensities of ground shaking. A vector comprising of the normalized static eccentricity ratio and the torsional radius to mass radius of gyration ratio is found to perform well at low shaking intensity levels, where the structure responds in an elastic manner. However, at high intensity levels where the structure undergoes significant excursions into the inelastic range of behaviour, the strength eccentricity is observed to be a better descriptor of torsional irregularity. A three-element vector comprising of the above indices is found to capture the maximum interstorey drifts accurately at all ground motion intensity levels. A seismic demand model for maximum interstorey drift, sensitive to the above torsional irregularity descriptors, is also defined.

Eficacia de la neuromodulacion transcutánea vs percutánea del nervio tibial en el síndrome de vejiga hiperactiva no neurogénica

Antecedentes: El tratamiento del síndrome de vejiga hiperactiva incluye desde modificaciones del estilo de vida, fisioterapia, anticolinérgicos, neuromodulacion y toxina botulínica. Debido a la refractariedad ha cobrado interés la neuromodulacion periférica. El objetivo fue evaluar la eficacia de la neuromodulacion transcutánea vs percutánea del nervio tibial en el síndrome de vejiga hiperactiva idiopática no neurogénica.&#x0D; Material y Métodos: Ensayo clínico aleatorizado en 61 pacientes durante enero-octubre de 2019. Se dividió en dos grupos: transcutánea (n=33) o percutánea (n=28). Se uso el estimulador (BioTENS) con 10 Hz, 200 us, durante 12 sesiones, con duración de 20 minutos cada sesión. Se valoro la eficacia mediante el diario vesical de 3 días, cuestionario de síntomas y calidad de vida, y escala de beneficio de tratamiento en la sesión 1, 6 y 12. Se realizo estadística descriptiva y correlación de variables con programa SPSS v22.0, y p ≤ 0.05 estadísticamente significativo.&#x0D; Resultados: La edad media fue 66 años. La frecuencia urinaria diurna y nocturna disminuyo, aumento el volumen urinario promedio, disminuyo el número de episodios de urgencia e incontinencia de urgencia sin diferencias estadísticamente significativa al comparar ambos tratamientos. La percepción de calidad de vida y mejoría en relación al tratamiento mejoro con ambas técnicas (p=&gt;0.05). No hubo efectos secundarios y la adherencia al tratamiento fue del 83.6 % (n=51). Se uso menor intensidad en la percutánea (4 mA vs 7 mA; p=0.0001).&#x0D; Conclusiones: Primer ensayo clínico aleatorizado realizado en el país que evalúa a eficacia en ambas técnicas, demostrando la no inferioridad.

The Physical and Psychological Experience of Rowing the North Atlantic Solo and Unassisted

The present study followed an individual's successful, record-setting, solo, unsupported row across the North Atlantic Ocean to gain an understanding of the physical and psychological experience of this extreme endurance feat. The participant was a 37-y-old male endurance athlete. Over the course of his nearly 39-d row, he provided daily ratings of effort, physical symptoms, and psychological experiences via a self-report questionnaire. Quantitative data were analyzed using simulation modelling analysis to examine within-day and cross-lagged correlations between perceived exertion and all other variables. Qualitative data were examined via thematic content analysis. Results showed that, on average, the participant experienced low levels of pain intensity, pain interference, fatigue interference, sleepiness, loneliness, boredom, anxiety, and frustration, in contrast to moderate scores for fatigue, restfulness, positive emotions, calmness, and confidence. There were statistically significant correlations between higher levels of perceived exertion and higher same-day levels of pain interference, fatigue, and fatigue interference, as well as lower same-day levels of calmness, loneliness, and boredom. Qualitative responses revealed 3 primary stressor types (internal physical, internal psychological, and external stressors) and 5 coping responses (acceptance/mindfulness, active response/problem solving, adjusting expectations/goal setting, distraction, and resignation). Study findings indicate that the extreme athlete experienced physical and emotional challenges, but he demonstrated positive adjustment via the frequent experience of positive emotions and proficient use of a broad set of coping strategies matched to the daily stressor being addressed.

Chinese development assistance and household welfare in Sub-Saharan Africa

Abstract We study the impact of Chinese aid on household welfare in Sub-Saharan Africa by combining data on Chinese development projects with data from Demographic and Health Surveys. Using difference-in-differences estimations and a matching technique, we analyze the effect of Chinese aid on three social development outcomes: education, and child health and nutrition. We find that Chinese aid projects improve education and child mortality in treatment areas but have no effects on child nutrition. A sectoral analysis further reveals that social sector projects successfully improve households’ health and education. Improvements in these outcomes may additionally be driven indirectly by a positive effect of Chinese aid on economic welfare in treatment areas. Regarding the distribution and scale of Chinese projects we find that our results hold for lower treatment intensity levels only, suggesting a non-linear effect of Chinese aid.

Deblurring Sinograms Using a Covolutional Neural Network to Achieve Fast X-ray Computed Tomography Scanning

X-ray computed tomography (CT) allows for visualization of the interior of solid objects in a non-destructive and non-invasive manner. However, producing high-precision measurements takes a long time because thousands of sharp transmission images are required to reconstruct CT volumes. To address this problem, we propose a CT measurement method based on Convolutional Neural Networks (CNNs) that yields sharp transmission images by deblurring blurry ones. In this method, first, blurry images are obtained in a short measurement time, then they are deblurred by CNNs with fine-tuning and integrated by linear interpolation. This method shortens the measurement time indirectly because the process related to the CNNs is fast with GPUs and the blurry images with low levels of noise intensity do not require a long time. Besides, the fine-tuning may improve the output images’ sharpness. According to our experimental results, the proposed method is fast and can maintain the quality of data to a certain extent.

Surgeons' posture and muscle strain during laparoscopic and robotic surgery.

It is assumed that conventional laparoscopy (LAP) and robotic-assisted laparoscopic surgery (RALS) differ in terms of the surgeon's comfort. This study compared muscle workload, work posture and perceived physical exertion of surgeons performing LAP or RALS. Colorectal surgeons with experience in advanced LAP and RALS performed one of each operation. Bipolar surface electromyography (EMG) recordings were made from forearm, shoulder and neck muscles, and expressed relative to EMG maximum (%EMGmax ). The static, median and peak levels of muscle activity were calculated, and an exposure variation analysis undertaken. Postural observations were carried out every 10 min, and ratings of perceived physical exertion before and after surgery were recorded. The study included 13 surgeons. Surgeons performing LAP showed higher static, median, and peak forearm muscle activity than those undertaking RALS. Muscle activity at peak level was higher during RALS than LAP. Exposure variation analysis demonstrated long-lasting periods of low-level intensity muscle activity in the shoulders for LAP, in the forearms for RALS, and in the neck for both procedures. Postural observations revealed a greater need for a change in work posture when performing LAP compared with RALS. Perceived physical exertion was no different between the surgical modalities. Minimally invasive surgery requires long-term static muscle activity with a high physical workload for surgeons. RALS is less demanding on posture.

Intensified visual clutter induces increased sympathetic signalling, poorer postural control, and faster torsional eye movements during visual rotation

Many dizzy patients express a hypersensitivity to visual motion and clutter. This study aims to investigate how exposure to rotating visual clutter affects ocular torsion, vertical skewing, body-sway, the autonomic pupillary response, and the subjective feeling of discomfort to the stimulation. Sixteen healthy subjects were exposed to 20 seconds rotational visual stimulation (72 deg/s; 50 deg visual field). Visual stimuli were comprised of black lines on a white background, presented at low and high intensity levels of visual clutter, holding 19 lines and 38 lines respectively. Ocular torsion and vertical skewing were recorded using the Chronos Eye Tracker, which also measured pupil size as a reflection of the autonomic response. Postural control was evaluated by measuring body-sway area on the Wii Balance Board. Values were compared to data retrieved 20 seconds before and after the optokinetic stimulation, as subjects viewed the stationary visual scene. The high intensity stimulus resulted in significantly higher torsional velocities. Subjects who were exposed to low intensity first exhibited higher velocities for both intensities. Both pupil size and body sway increased for the higher intensity to both the moving and stationary visual scene, and were positively correlated to torsional velocity. In conclusion, exposure to visual clutter was reflected in the eye movement response, changes in postural control, and the autonomic response. This response may hold clinical utility when assessing patients suffering from visual motion hypersensitivity, while also providing some context as to why some healthy people feel discomfort in visually cluttered surroundings.

On the Periodic Change of the Luminosity of the Cosmic Sources with an Active Medium

The presence of an internal layer with an active medium in a hot radiation source is considered, which can be described by a quantum two-level system located near equilibrium. The population of the upper and lower levels is approximately equal. It is shown that during convection from deeper hot layers, which supports the inversion of the populations of the active system, generation of induced radiation pulses is possible, the intensity of which is comparable to or greater than the intensity of the background spontaneous radiation of the source. With a sufficient thickness of the surface layers due to the effects of radiation scattering in them, the emission spectrum of a completely black body may well form there. Pulse generation near a previously detected new threshold of induced radiation can lead to a periodic change in the radiation intensity of the source as a whole. This threshold is determined by the equality of the squared population inversion to the total number of states. The generation of pulses of induced radiation is considered both in Einstein's representation, on the basis of balanced equations, and using a semiclassical description for small values of population inversion and for low levels of electric field intensity, when the Rabi frequency is less than the line width. The description of the induced radiation process is reduced to a one-parameter system of equations. Periodic solutions are represented by closed trajectories on the phase plane (relative density of quanta, relative density of population inversion). A similar layer with an active medium, which can be described by a quantum two-level system located near equilibrium, can exist in stars and is most likely localized in the photosphere. If there is significant convection in the star’s atmosphere, conditions can be realized for generating pulses of induced radiation. It turns out that one can see the similarity of the obtained solutions with known observations of changes in the luminosity of Cepheid stars (Cepheus delta and the North Star).