scholarly journals Interaction feature of caterpillar tracks with soil under significant axial displacements of pressure center

2021 ◽  
Vol 839 (5) ◽  
pp. 052023
Author(s):  
R Yu Dobretsov ◽  
V A Sokolova ◽  
I A Teterina ◽  
S V Malyukov ◽  
A A Aksenov ◽  
...  
Keyword(s):  
Pressure Center

POSTURAL STABILITY IN PATIENTS WITH LATENT TRIGGER ZONES OF NECK MUSCULATURE

2019 ◽  
pp. 114-123
Author(s):  
E.R. Mukhametova ◽  
A.D. Militskova ◽  
T.V. Baltina
Keyword(s):  
Postural Control ◽  
Postural Stability ◽  
Test Group ◽  
Trigger Points ◽  
Control Group ◽  
Neck Muscle ◽  
Pressure Center ◽  
Cervical Muscles ◽  
Equilibrium Function ◽  
Romberg Test

There are many reasons for postural disorder development, but dysfunction of the cervical spine muscles is the most disputable reason. The purpose of the study is to reveal the influence of latent myogenic trigger zones of the cervical muscles on postural resistance. Materials and Methods. The authors used the method of computer posturography. Latent myogenic trigger zones (LMTZs) were determined by an indurated nodule or bundle in the neck muscle and by hyperesthesia in this zona. Assessment of postural resistance in subjects with LMTZs was carried out using standard posturography tests and Romberg test. Both classical and vector indicators were evaluated in a standard sample. Results. In fact, only vector indicators changed significantly in subjects with multiple LMTZs (4 or more). Thus, a decrease in the equilibrium function quality was established, as well as an increase in the average linear velocity of the pressure center and an increase in the normalized vectorogram area if compared with the indices in the control group and the group with sporadic LMTZs (from 1 to 3). The obtained results indicate a postural control decrease in individuals with multiple LMTZs. Subjects with sporadic LMTZs demonstrated a significant decrease in classical and a number of vector indicators, which shows the improvement in postural resistance in this test group. In Romberg test, all subjects with LMTZs, regardless of the zone number, showed an increasd Romberg coefficient. Conclusion. Multiple LMTZs of cervical muscles can reduce postural stability through increased afferentation from the cervical proprioreceptors. It is more obvious during in case of eye control elimination. Keywords: latent myogenic trigger points, postural control, posturography, Romberg test. Выделяют множество причин развития постуральных нарушений, среди которых дисфункция мышц шейного отдела позвоночника является наиболее спорной. Цель исследования. Выявить влияние латентных миогенных триггерных зон шейной мускулатуры на постуральную устойчивость. Материалы и методы. Использовался метод компьютерной стабилографии. Латентные миогенные триггерные зоны (лМТЗ) определялись по наличию в мышце шеи уплотненного узелка или пучка и по повышенной болевой чувствительности в этой области. Оценка постуральной устойчивости у испытуемых с лМТЗ осуществлялась с помощью стандартного стабилографического тестирования и теста Ромберга. В стандартной пробе оценивались как классические, так и векторные показатели. Результаты. Показано, что у испытуемых с множественными лМТЗ (4 и более) достоверно изменяются только векторные показатели. Так, установлено снижение качества функции равновесия, а также повышение средней линейной скорости центра давления и увеличение нормированной площади векторограммы по сравнению показателями в группе контроля и группе с единичными лМТЗ (от 1 до 3), что указывает на снижение постурального контроля у лиц с множественными лМТЗ. У испытуемых с единичными лМТЗ отмечено достоверное снижение классических показателей и ряда векторных, что свидетельствует об улучшении постуральной устойчивости в данной группе испытуемых. В пробе Ромберга все субъекты с лМТЗ независимо от количества последних показали повышение коэффициента Ромберга. Выводы. Множественные лМТЗ шейной мускулатуры могут снизить постуральную устойчивость через усиление афферентации от шейных проприорецепторов, что наиболее выражено при элиминации зрительного контроля. Ключевые слова: латентные миогенные триггерные точки, постуральный контроль, стабилография, тест Ромберга.

scholarly journals Present temperature, precipitation and rain-on-snow climate in Svalbard

2020 ◽  
Author(s):  
Siiri Wickström ◽  
Marius O. Jonassen ◽  
John Cassano ◽  
Timo Vihma ◽  
Jørn Kristiansen
Keyword(s):  
Weather Prediction ◽  
Open Water ◽  
Low Pressure ◽  
Numerical Weather Prediction Model ◽  
The Arctic ◽  
Pressure Center ◽  
Climate Conditions ◽  
Temperature And Precipitation ◽  
Pressure Centre ◽  
Local Variability

<p>Potentially high-impact warm and wet winter conditions have become increasingly common in recent decades in the arctic archipelago of Svalbard. In this study, we document present 2m temperature, precipitation and rain-on-snow (ROS) climate conditions in Svalbard and relate them to different atmospheric circulation (AC) types. For this purpose, we utilise a set of observations together with output from the high resolution numerical weather prediction model AROME-Arctic. We find that 2m median temperatures vary the most across AC types in winter and spring, and the least in summer. Southerly and southwesterly flow is associated with 10th percentile 2m temperatures above freezing in all seasons. In terms of precipitation, we find the highest amounts and intensities with onshore flow over open water. Sea ice appears to play a strong role in the local variability in both 2m temperature and precipitation. ROS is a frequent phenomenon in the study period, in particular below 250 m ASL. In winter, ROS only occurs with AC types from the southerly sector or during the passage of a low pressure centre or trough. Most of these events occur during southwesterly flow, with a low pressure center west of Svalbard.</p><p> </p>

scholarly journals Impacts of Late-Spring North Eurasian Soil Moisture Variation on Summer Rainfall Anomalies in Northern East Asia

2021 ◽  
Author(s):  
Yinghan Sang ◽  
Hong-Li Ren ◽  
Yi Deng ◽  
Xiaofeng Xu ◽  
Xueli Shi ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Temperature Gradient ◽  
East Asia ◽  
Summer Rainfall ◽  
Low Pressure ◽  
Late Spring ◽  
Boreal Summer ◽  
Pressure Center ◽  
North Eurasia ◽  
The Impact

Abstract This paper reports findings from a diagnostic and modeling analysis that investigates the impact of the late-spring soil moisture anomaly over North Eurasia on the boreal summer rainfall over northern East Asia (NEA). Soil moisture in May in the region from the Kara-Laptev Sea coasts to Central Siberian Plateau is found to be negatively correlated with the summer rainfall from Mongolia to Northeast China. The atmospheric circulation anomalies associated with the anomalously dry soil are characterized by a pressure dipole with the high-pressure center located over North Eurasia and the low-pressure center over NEA, where an anomalous lower-level moisture convergence occurs, favoring rainfall formation. Diagnoses and Modeling experiments demonstrate that the effect of the spring low soil moisture over North Eurasia may persist into the following summer through modulating local surface latent and sensible heat fluxes, increasing low-level air temperature at higher latitudes, and effectively reducing the meridional temperature gradient. The weakened temperature gradient could induce the decreased zonal wind and the generation of a low-pressure center over NEA, associated with a favorable condition of local synoptic activity. The above relationships and mechanisms are vice versa for the prior wetter soil and decreased NEA rainfall. These findings suggest that soil moisture anomalies over North Eurasia may act as a new precursor providing an additional predictability source for better predicting the summer rainfall in NEA.

scholarly journals Dynamical and Synoptic Characteristics of Heavy Rainfall Episodes in Southern Brazil

2007 ◽  
Vol 135 (2) ◽  
pp. 598-617 ◽  
Author(s):  
Mateusda Silva Teixeira ◽  
Prakki Satyamurty
Keyword(s):  
Heavy Rainfall ◽  
Moisture Flux ◽  
Southern Brazil ◽  
Mean Flow ◽  
Pressure Center ◽  
Average Rainfall ◽  
Meridional Winds ◽  
The Mean ◽  
Low Level Jet ◽  
Atmospheric Variables

Abstract The dynamical and synoptic characteristics that distinguish heavy rainfall episodes from nonheavy rainfall episodes in southern Brazil are discussed. A heavy rainfall episode is defined here as one in which the 50 mm day−1 isohyet encloses an area of not less than 10 000 km2 in the domain of southern Brazil. One hundred and seventy such events are identified in the 11-yr period of 1991–2001. The mean flow patterns in the period of 1–3 days preceding the episodes show some striking synoptic-scale features that may be considered forerunners of these episodes: (i) a deepening midtropospheric trough in the eastern South Pacific approaches the continent 3 days before, (ii) a surface low pressure center forms in northern Argentina 1 day before, (iii) a northerly low-level jet develops over Paraguay 2 days before, and (iv) a strong moisture flux convergence over southern Brazil becomes prominent 1 day before the episode. A parameter called rainfall quantity, defined as the product of the area enclosed by the 50 mm day−1 isohyet and the average rainfall intensity, is correlated with fields of atmospheric variables such as 500-hPa geopotential and 850-hPa meridional winds. Significant lag correlations show that the anomalies of some atmospheric variables could be viewed as precursors of heavy rainfall in southern Brazil that can be explored for use in improving the forecasts.

Pressure and Winds

2000 ◽  
Author(s):  
C. David Whiteman
Keyword(s):  
High Pressure ◽  
Pressure Gradient ◽  
Pressure Difference ◽  
Low Pressure ◽  
Pressure Center ◽  
Vertical Column ◽  
Wind Speeds ◽  
Weather Observations ◽  
Stormy Weather ◽  
Rotation Of The Earth

Atmospheric pressure at a given point in the atmosphere is the weight of a vertical column of air above that level. Differences in pressure from one location to another cause both horizontal motions (winds) and vertical motions (convection and subsidence) in the atmosphere. Vertical motions, whether associated with high and low pressure centers or with other meteorological processes, are the most important motions for producing weather because they determine whether clouds and precipitation form or dissipate. The location of high and low pressure centers is a key feature on weather maps, providing information about wind direction, wind speed, cloud cover, and precipitation. Pressure-driven winds carry air from areas where pressure is high to areas where pressure is low. However, the winds do not blow directly from a high pressure center to a low pressure center. Because of the effects of the rotation of the earth and friction, winds blow clockwise out of a high pressure center and counterclockwise into a low pressure center in the Northern Hemisphere. These wind directions are reversed in the Southern Hemisphere. The strength of the wind is proportional to the pressure difference between the two regions. When the pressure difference or pressure gradient is strong, wind speeds are high; when the pressure gradient is weak, wind speeds are low. As air flows out of a high pressure center, air from higher in the atmosphere sinks to replace it. This subsidence produces warming and the dissipation of clouds and precipitation. As air converges in a low pressure center, it rises and cools. If the air is sufficiently moist, cooling can cause the moisture to condense and form clouds. Further lifting of the air can produce precipitation. Thus, rising pressure readings at a given location indicate the approach of a high pressure center and fair weather, whereas falling pressure readings indicate the approach of a low pressure center and stormy weather. The vertical motions caused by the divergence of air out of a high pressure center or the convergence of air into a low pressure center are generally weak, with air rising or sinking at a rate of several cm per second, and they cannot be measured by routine weather observations.

scholarly journals Tillage and Low‐Pressure Center‐Pivot Irrigation Effects on Corn Yield 1

1985 ◽  
Vol 77 (2) ◽  
pp. 258-263
Author(s):  
W. W. Wilhelm ◽  
L. N. Mielke ◽  
J. R. Gilley
Keyword(s):  
Low Pressure ◽  
Corn Yield ◽  
Pressure Center ◽  
Center Pivot ◽  
Irrigation Effects

Analysis on the Feet-Pressure between Flatfoot and Normal Foot

2012 ◽  
Vol 442 ◽  
pp. 149-153
Author(s):  
Wei Fei Fang
Keyword(s):  
Contact Area ◽  
Pressure Difference ◽  
Test System ◽  
Dynamic State ◽  
Bottom Pressure ◽  
Pressure Center ◽  
Static State ◽  
Great Capacity ◽  
Average Value

Inquire into normal foot and the foot bottom of the flatfoot pressure difference to provide a reference. Carring on footprint diagraph to 206 volunteers, is divided into normal foot according to the foot bow blank width in the footprint 157, 49 flatfoots.Adopt foot bottom pressure's distributing to test system is checked the foot bottom pressure to carry on diagraph to 2 sets.Measure medium be checked request to take off shoes and socks to tread Tai to walk as usual, take three average value, dynamic state's recording 2 sets is checked foot bottom pressure.As usual fully the contact area of heel and front forefootis bigger than flatfoot, p<0.05;As usual fully the bow contact area is smaller than flatfoot, p<0.05.As usual fully bow and front the blunt quantity that forefootis subjected to is smaller than flatfoot, p<0.05;Normal heel is hurtled Be had great capacity to flatfoot, p<0.05;Under static state and dynamic state circumstance the pressures of the forefootand the foot bow acceptance are all bigger than normal foot before the flatfoot, p<0.05.Conclusion:Flatfoot the pressure center is more intensive while hitting the ground, its foot bow and front the blunt quantity been subjected to by forefootis a little bit greatly.

Resposta do Controle Postural em Superfície Inclinada: uma Revisão de Literatura

2019 ◽  
Vol 23 (1) ◽  
pp. 61
Author(s):  
Silvana Rocha Silveira
Keyword(s):  
Horizontal Plane ◽  
Human Mobility ◽  
Clinical Intervention ◽  
The Elderly ◽  
Force Platform ◽  
Pressure Center ◽  
Inclined Surfaces ◽  
Contrôle Postural ◽  
Urban Accessibility ◽  
Environmental Predictor

ResumoO controle postural é um requisito imprescindível para a execução das habilidades motoras durante as atividades de vida diária, logo, há a necessidade constante de ajuste dos segmentos corporais para garantir a autonomia e a independência da mobilidade humana. Os ajustes posturais são resultantes da interação do sistema sensório-motor e da sua correlação com o meio ambiente, produzindo orientação e estabilidade postural esperada durante a execução das atividades, sendo essa estática ou dinâmica. Deste modo, o objetivo do estudo foi apresentar os impactos funcionais ocorridos durante a posição de pé parada ou em movimento em superfície de inclinada, principalmente, entre os idosos. O estudo se fundamentou na revisão bibliográfica, no período temporal de 2006 a 2016, por meio da análise das bases de dados em Pubmed, Ebsco, SciELO, Medline e Lilacs, com a utilização dos termos: Plataforma de força, plano inclinado, plano horizontal e comportamento do centro de pressão. Os resultados apontaram que as situações rotineiras do dia a dia, realizadas em superfícies inclinadas, como um mero ato de subir ou até ficar parado em uma ladeira, pode ser um preditor ambiental para instabilidade postural, tornando-se necessário a reavaliação do olhar da intervenção terapêutica meramente clínica, passando a ampliar para as circunstâncias vinculadas com as questões da acessibilidade urbana. Palavras chaves: Plataforma de Força. Plano Horizontal. Comportamento do Centro de Pressão. Abstract Postural control is an essential requirement for the performance of motor skills during  daily living activities, so there is a constant need to adjust body segments to guarantee the autonomy and independence of human mobility. Postural adjustments result from the interaction of the sensorimotor system and their  correlation with the environment, producing orientation and postural stability expected during the execution of the activities, being static or dynamic. Thus, the objective of the study was to present the functional impacts occurred during standing or moving position on inclined surface, mainly among the elderly. The study was based on the bibliographic review, in the period from 2006 to 2016, through the analysis of databases in Pubmed, Ebsco, SciELO, Medline and Lilacs, using the terms Force platform, inclined plane, horizontal plane and pressure center behavior. The results showed that routine everyday situations on inclined surfaces, such as a mere act of climbing or even standing on a slope, may be an environmental predictor for postural instability, making it necessary to re-evaluate the clinical intervention, starting to extend the issues of urban accessibility to the related circumstances. Keywords: Force Platform. Horizontal Plane. Pressure Center Behavior.

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