RESEARCH OF HUMAN POSTURAL BALANCE PARAMETERS

In present article postural balance between subjects with stroke and healthy subjects, is being investigated with eyes opened and eyes closed. In the research participated 30 healthy subjects and 15 subjects with stroke. At the same time two experimental measurements were performed – postural balance was measured using balance platform and oscillations of the centre of mass were observed using two-axial accelerometer. It was noted, that amplitudes of subjects with stroke were larger almost two times than control group’s of healthy subjects. It was find out, that ratios of pressure distribution on both left and right legs are in range from 1 to 0.9 for healthy subjects, and ratios below 0.9 are common for subjects with stroke. When subjects were standing with eyes closed, sway amplitudes were higher and the ratios of load distribution on left and right legs were lower.

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SYNCHRONIZATION MEASURES OF THE SCALP ELECTROENCEPHALOGRAM CAN DISCRIMINATE HEALTHY FROM ALZHEIMER'S SUBJECTS

International Journal of Neural Systems ◽

10.1142/s0129065707000932 ◽

2007 ◽

Vol 17 (02) ◽

pp. 61-69 ◽

Cited By ~ 48

Author(s):

MARK A. KRAMER ◽

FEN-LEI CHANG ◽

MAURICE E. COHEN ◽

DONNA HUDSON ◽

ANDREW J. SZERI

Keyword(s):

Cognitive Impairment ◽

Healthy Subjects ◽

Phase Synchronization ◽

Eyes Closed ◽

Eeg Data ◽

Two Measures ◽

Left And Right ◽

Scalp Electroencephalogram ◽

Occipital Lobes ◽

Electroencephalogram Eeg

Three synchronization measures are applied to scalp electroencephalogram (EEG) data collected from 20 patients diagnosed to have either: (1) no dementia, (2) mild cognitive impairment (MCI), or (3) Alzheimer's disease (AD). We apply the three synchronization measures — the phase synchronization, and two measures of nonlinear interdependency — to the data collected from awake patients resting with eyes closed. We show that the synchronization in potential between electrodes near the left and right occipital lobes provides a statistically significant discriminant between the healthy and AD subjects, and the MCI and AD subjects. None of the three measures appears able to distinguish between the healthy and MCI subjects, although MCI subjects show synchronization values intermediate between healthy subjects (with high synchronization values) and AD subjects (with low synchronization values) on average.

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Gender Differences in Postural Stability among 13-Year-Old Alpine Skiers

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17113859 ◽

2020 ◽

Vol 17 (11) ◽

pp. 3859 ◽

Cited By ~ 1

Author(s):

Agnieszka D. Jastrzębska

Keyword(s):

Gender Differences ◽

Postural Balance ◽

Lactate Concentration ◽

Blood Lactate Concentration ◽

Body Sway ◽

Foot Pressure ◽

Eyes Closed ◽

Before And After ◽

Eyes Open ◽

Alpine Skiers

This experiment examined changes in body sway after Wingate test (WAnT) in 19 adolescents practicing alpine skiing, subjected to the same type of training load for 4–5 years (10 girls and nine boys). The postural examinations were performed with eyes open (EO), eyes closed (EC), and sway reverenced vision (SRV) in the medial-lateral (ML) and anterior-posterior (AP) planes. The displacement of center of foot pressure (CoP), range of sway (RS), mean sway velocity (MV), way length, and surface area were measured in bipedal upright stance before and after the WAnT to assess the influence of fatigue on postural balance. There were no significant differences in WAnT parameters between girls and boys. Relative peak power (RPP), relative total work (RWtot) were (girls vs. boys) 8.89 ± 0.70 vs. 9.57 ± 1.22 W/kg, p < 0.05 and 227.91 ± 14.98 vs. 243.22 ± 30.24 W/kg, p < 0.05 respectively. The fatigue index (FI) was also on similar level in both genders; however, blood lactate concentration (BLa) was significantly higher in boys (10.35 ± 1.16 mM) than in girls (8.67 ± 1.35 mM) p = 0.007. In the EO examination, statistically significant differences between resting and fatigue conditions in the whole group and after the division into girls and boys were found. In fatigue conditions, significant gender differences were noted for measurements in the ML plane (sway path and RS) and RS in the AP plane. Comparison of the three conditions shows differences between EO vs. EC and SRV in AP plane measured parameters, and for RS in ML plane in rest condition in girls. The strong correlations between FI and CoP parameters mainly in ML plane in the whole group for all examination conditions were noted. By genders, mainly RS in ML plane strongly correlates with FI (r > 0.7). No correlation was found between BLa and CoP parameters (p > 0.06). The presented results indicate that subjecting adolescents of both genders to the same training may reduce gender differences in the postural balance ability at rest but not in fatigue conditions and that girls are significantly superior in postural balance in the ML plane than boys. It was also shown that too little or too much information may be destructive to postural balance in young adolescents.

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A Comparison of Analytical Predictions With Experimental Measurements of Transmission Error of Misaligned Loaded Gears

6th International Power Transmission and Gearing Conference: Advancing Power Transmission Into the 21st Century ◽

10.1115/detc1992-0002 ◽

1992 ◽

Author(s):

Harsh Vinayak ◽

Donald R. Houser

Keyword(s):

Experimental Data ◽

Load Distribution ◽

Theoretical Calculations ◽

Data Acquisition System ◽

Transmission Error ◽

Test Facility ◽

Experimental Measurements ◽

Gear Pair ◽

Prediction Program ◽

Dynamic Transmission Error

Abstract This paper deals with the experimental study of dynamic transmission error of a gear pair. Two aspects of the experiment are discussed : 1) design of the test facility and data acquisition system and 2) comparison of transmission error and load distribution with experimental data. Several gears were tested under varying misalignments. A prediction program LDP (Load distribution Program) was used for theoretical calculations of dynamic transmission error.

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Standard reference values of weight and maximum pressure distribution in healthy adults aged 18–65 years in Germany

Journal of PHYSIOLOGICAL ANTHROPOLOGY ◽

10.1186/s40101-020-00246-6 ◽

2020 ◽

Vol 39 (1) ◽

Author(s):

D. Ohlendorf ◽

K. Kerth ◽

W. Osiander ◽

F. Holzgreve ◽

L. Fraeulin ◽

...

Keyword(s):

Body Weight ◽

Pressure Distribution ◽

Reference Values ◽

Effect Size ◽

Weight Distribution ◽

Age Groups ◽

Healthy Adults ◽

The Body ◽

Maximum Pressure ◽

Left And Right

Abstract Background The aim of this study was to collect standard reference values of the weight and the maximum pressure distribution in healthy adults aged 18–65 years and to investigate the influence of constitutional parameters on it. Methods A total of 416 healthy subjects (208 male / 208 female) aged between 18 and 65 years (Ø 38.3 ± 14.1 years) participated in this study, conducted 2015–2019 in Heidelberg. The age-specific evaluation is based on 4 age groups (G1, 18–30 years; G2, 31–40 years; G3, 41–50 years; G4, 51–65 years). A pressure measuring plate FDM-S (Zebris/Isny/Germany) was used to collect body weight distribution and maximum pressure distribution of the right and left foot and left and right forefoot/rearfoot, respectively. Results Body weight distribution of the left (50.07%) and right (50.12%) foot was balanced. There was higher load on the rearfoot (left 54.14%; right 55.09%) than on the forefoot (left 45.49%; right 44.26%). The pressure in the rearfoot was higher than in the forefoot (rearfoot left 9.60 N/cm2, rearfoot right 9.51 N/cm2/forefoot left 8.23 N/cm2, forefoot right 8.59 N/cm2). With increasing age, the load in the left foot shifted from the rearfoot to the forefoot as well as the maximum pressure (p ≤ 0.02 and 0.03; poor effect size). With increasing BMI, the body weight shifted to the left and right rearfoot (p ≤ 0.001, poor effect size). As BMI increased, so did the maximum pressure in all areas (p ≤ 0.001 and 0.03, weak to moderate effect size). There were significant differences in weight and maximum pressure distribution in the forefoot and rearfoot in the different age groups, especially between younger (18–40 years) and older (41–65 years) subjects. Discussion Healthy individuals aged from 18 to 65 years were found to have a balanced weight distribution in an aspect ratio, with a 20% greater load of the rearfoot. Age and BMI were found to be influencing factors of the weight and maximum pressure distribution, especially between younger and elder subjects. The collected standard reference values allow comparisons with other studies and can serve as a guideline in clinical practice and scientific studies.

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Does the HM mechanism work in string theory?

Canadian Journal of Physics ◽

10.1139/cjp-2012-0163 ◽

2013 ◽

Vol 91 (1) ◽

pp. 75-80

Author(s):

Alireza Sepehri ◽

Somayyeh Shoorvazi ◽

Mohammad Ebrahim Zomorrodian

Keyword(s):

Hilbert Space ◽

Black Hole ◽

String Theory ◽

Correspondence Principle ◽

Black Hole Entropy ◽

Closed String ◽

Centre Of Mass ◽

Final State ◽

Information Transformation ◽

Left And Right

The correspondence principle offers a unique opportunity to test the Horowitz and Maldacena mechanism at the correspondence point “the centre of mass energies around (Ms/(gs)2)”. First by using the Horowitz and Maldacena proposal, the black hole final state for closed strings is studied and the entropy of these states is calculated. Then, to consider the closed string states, a copy of the original Hilbert space is constructed with a set of creation–annihilation operators that have the same commutation properties as the original ones. The total Hilbert space is the tensor product of the two spaces Hright ⊗ Hleft, where in this case Hleft/right denote the physical quantum state space of the closed string. It is shown that closed string states can be represented by a maximally entangled two-mode squeezed state of the left and right spaces of closed string. Also, the entropy for these string states is calculated. It is found that black hole entropy matches the closed string entropy at transition point. This means that our result is consistent with correspondence principle and thus HM mechanism in string theory works. Consequently the unitarity of the black hole in string theory can be reconciled. However Gottesman and Preskill point out that, in this scenario, departures from unitarity can arise due to interactions between the collapsing body and the infalling Hawking radiation inside the event horizon and information can be lost. By extending the Gottesman and Preskill method to string theory, the amount of information transformation from the matter to the state of outgoing Hagedorn radiation for closed strings is obtained. It is observed that information is lost for closed strings.

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Palm Creases Analysis in Students and Staff of a Teaching Hospital in Kathmandu

Medical Journal of Shree Birendra Hospital ◽

10.3126/mjsbh.v18i1.21039 ◽

2019 ◽

Vol 18 (1) ◽

pp. 51-58

Author(s):

Nirju Ranjit ◽

Bidur Adhikari ◽

Rajani Shrestha ◽

Anusuya Shrestha ◽

Rosha Bhandari ◽

...

Keyword(s):

Healthy Subjects ◽

Age Groups ◽

Cross Sectional Study ◽

Sectional Study ◽

Cross Sectional ◽

Closed Type ◽

Long Time ◽

Left And Right ◽

Palm Print ◽

The Individual

Introduction: Palm creases have been studied for a long time and have been recently found to be helpful in tracking underlying medical and genetic conditions. Scientific study and typing of palm prints have been found to be lacking in the Nepalese population Methods: A cross sectional study was done on 252 subjects, 153 male and 99 females, from Kathmandu, Nepal. Subjects were selected by purposive sampling from different age groups. Demographic profile including age, sex, and handedness was collected. Palm print pattern was recorded by digital photography. Each photograph was analysed visually by single observer and pattern of palm crease was noted. Variation of each crease was also noted. Results: On the basis of relation between radial longitudinal crease and proximal transverse crease, 17.3% subjects had open type of palm crease which was significantly more in females while 76.6% subjects had closed type crease which was significantly more in males. Meeting type of palm crease was found in 5.7% of subjects. On the basis of relation between proximal and distal transverse crease, normal crease type was found in 90.1% of subjects, Simian type was found in 7.7% subjects and Sydney type was found in 1.4% of subjects. The concordance of this pattern in left and right palms was found statistically significant. Conclusions: This study presented data from 252 seemingly normal healthy subjects and found that most of them had the normal with no branching, that is normal 1 and closed crease types. Most of the individual major creases were seen to be branched type.

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Simulation of a Layered Resonator for a Microfluidic Ultrasonic Separator

ASME 4th International Conference on Nanochannels, Microchannels, and Minichannels, Parts A and B ◽

10.1115/icnmm2006-96247 ◽

2006 ◽

Author(s):

Yijun Shen ◽

Mark A. Atherton

Keyword(s):

Energy Density ◽

Pressure Distribution ◽

Standing Wave ◽

Acoustic Pressure ◽

Separation Performance ◽

Experimental Measurements ◽

Driving Frequency ◽

Stored Energy ◽

Acoustic Characteristics ◽

Small Spherical Particle

This paper focuses on the simulation of a layered resonator for a microfluidic ultrasonic separator with a special emphasis on analysing the stored energy-frequency product in the microfluid chamber. Since the acoustic force acting on a small spherical particle in a standing wave in the cavity of an ultrasonic separator is proportional to the product of the energy density in the standing wave and the driving frequency, the energy-frequency product can be used as a prediction of the separation performance in an ultrasonic separator. The electro-acoustic characteristics of the resonator under different conditions are also investigated. In particular, the influence of the reflector thickness on the stored energy-frequency product of the layered resonator is examined. Furthermore, the acoustic pressure distribution in the fluid chamber of the ultrasonic separator is investigated in detail. Predicted results from simulations compare well with experimental measurements and show that the model can be used to predict the electro-acoustic characteristics and the separation performance.

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Static Postural Balance in Modern Pentathletes: A Pilot Study

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph16101760 ◽

2019 ◽

Vol 16 (10) ◽

pp. 1760 ◽

Cited By ~ 1

Author(s):

Dorota Sadowska ◽

Tomasz Sacewicz ◽

Małgorzata Lichota ◽

Justyna Krzepota ◽

Maria Ładyga

Keyword(s):

Postural Balance ◽

Postural Sway ◽

Control Group ◽

Physically Active ◽

Eyes Closed ◽

Test Conditions ◽

The Stability ◽

High Level ◽

The Impact ◽

Conscious Control

Postural balance is a key element of shooting effectiveness, which determines the outcome of modern pentathlon competitions. The aim of the study is to examine the postural balance of 27 pentathletes (12 females and 15 males; mean age: 18.0 ± 1.8 years), and 26 physically active, untrained subjects (12 females and 14 males; mean age: 22.5 ± 1.4 years), and to investigate the impact of footwear on the stability of the shooting position in pentathletes. Methods: Static postural balance was examined during quiet stance in four test conditions (standing in footwear with eyes opened, standing in footwear with eyes closed, standing barefoot with eyes opened, and standing barefoot with eyes closed). During each postural balance measurement, the participant remained still on the platform, with their arms in front of their body. Postural balance in the shooting position was only evaluated in the group of pentathletes. The athlete was asked to assume a comfortable shooting position on the platform and to aim at the target. Standard pentathlon targets and pistols were used in the study. Measurements were carried out twice (barefoot and in footwear). Results: In all conditions, pentathletes achieved lower values of posturographic measures than in the control group. In non-visual conditions, measures describing the surface area of the centre of pressure decreased in pentathletes and increased in the control group. Both pentathletes and non-athletes were equally stable barefoot as in footwear. Footwear did not affect postural sway in the shooting position in pentathletes. Conclusions: Pentathletes were found to have significantly better stance stability and were less vision-dependent in postural balance than untrained subjects. Bearing in mind that the shooting position of pentathletes was as stable barefoot as in footwear, the main factors which were most likely responsible for minimising body oscillations in the pentathletes were their high level of concentration and conscious control of body alignment.

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Identification of the under-tie pad material characteristics for stress state reduction

Proceedings of the Institution of Mechanical Engineers Part F Journal of Rail and Rapid Transit ◽

10.1177/0954409719890156 ◽

2019 ◽

Vol 234 (10) ◽

pp. 1227-1237 ◽

Cited By ~ 1

Author(s):

Jacob M Branson ◽

Marcus S Dersch ◽

Arthur de Oliveira Lima ◽

J Riley Edwards ◽

Josue Cesar Bastos

Keyword(s):

Stress State ◽

Pressure Distribution ◽

Load Distribution ◽

Track Structure ◽

State Reduction ◽

Track Geometry ◽

Railroad Tracks ◽

Material Characteristics ◽

Heavy Haul ◽

Insight Into

The degradation of ballast particles and concrete crossties in heavy-haul railroad tracks poses problems such as inhibiting proper drainage and disturbing track geometry. under-tie pads offer a solution to reduce crosstie–ballast stresses by improving load distribution through the track structure and reducing pressures on ballast particles and the crosstie surface. Despite the emergence of under-tie pads on heavy-haul corridors, optimal characteristics for the reduction of the tie–ballast stress state have not been defined in literature. In this research, several under-tie pad products and generic materials with various thicknesses and hardnesses were studied to identify appropriate properties of under-tie pad products for pressure distribution. The findings from this research provide an insight into how material characteristics influence the pressure mitigation performance of under-tie pads. Results from this study indicate that thickness is the most crucial metric determining under-tie pad performance in reducing ballast degradation; hardness and material type also have an effect, but to a lesser degree.

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