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106,133
result(s) for
"physical variables"
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Age, Height, and Sex on Motor Evoked Potentials: Translational Data From a Large Italian Cohort in a Clinical Environment
by
Cantone, Mariagiovanna
,
Lanza, Giuseppe
,
Fisicaro, Francesco
in
central motor conduction time
,
Clinical medicine
,
Conduction
2019
Motor evoked potentials (MEPs) to transcranial magnetic stimulation (TMS) are known to be susceptible to several sources of variability. However, conflicting evidences on individual characteristics in relatively small sample sizes have been reported. We investigated the effect of age, height, and sex on MEPs of the motor cortex and spinal roots in a large cohort.
A total of 587 subjects clinically and neuroradiologically intact were included. MEPs were recorded during mild tonic contraction through a circular coil applied over the \"hot spot\" of the first dorsal interosseous and tibialis anterior muscles (TAs), bilaterally. Central motor conduction time (CMCT) was estimated as the difference between MEP cortical latency and the peripheral motor conduction time (PMCT) by cervical or lumbar magnetic stimulation. Peak-to-peak MEP amplitude to cortical stimulation and right-to-left difference of each parameter were also measured.
After Bonferroni correction, general linear (multiple) regression analysis showed that both MEP cortical latency and PMCT at four limbs positively correlated with age and height. At lower limbs, an independent effect of sex on the same measures was also observed (with females showing smaller values than males). CMCT correlated with both age (negatively) and height (positively) when analyzed by a single regression; however, with a multiple regression analysis this significance disappeared, due to the correction for the multicollinearity within the dataset.
Physical individual features need to be considered for a more accurate and meaningful MEPs interpretation. Both in clinical practice and in research setting, patients and controls should be matched for age, height, and sex.
Journal Article
The effect of basic strength training on developing some physical variables in football for beginners
Skillful performances require strength in a fundamental way, and its importance, role, and structure emerge from one activity to another according to the requirements set by the situations of this activity to reach the higher levels. The purpose of this paper is to establishing basic strength training exercises to developing some physical variables for beginners and to identify the effect of the exercises. A sample of (36) beginners, from the football school in Wasit Governorate, (age = 10.5 ± 1.5 years, height = 142.32 ± 3.87 cm, mass 38.95 ± 3.71 kg) participated in the study. The participants in the experimental group (n=36) completed pre-tests and post-tests.The results of the experimental sample show that there was a significant improvement in the mean scores for basic strength on the post-test compared to the pre-test. The mean score Sprint 30 m from (5.95 to 5.08, p<0.005), the mean score for the Bend the torso forward and down from standing from (1.41 to 3.91, p<0.005), (Agility from (10.55 to 8.57, p<0.005), and the mean score for (measuring eye-leg coordination) from (13.49 to 9.93, p<0.005). The most important conclusions are that the exercises have a clear impact on the players’ abilities and in a positive direction. It has become clear to distinguish the differences between the two research groups in terms of the external appearance of the muscles and the positive impact on the psychological state.
Journal Article
Physical Variable Measurement Techniques for Fault Detection in Electric Motors
by
Aguayo-Tapia, Sarahi
,
Ramirez-Cortes, Juan Manuel
,
Rangel-Magdaleno, Jose de Jesus
in
Analysis
,
Automobiles, Electric
,
Bearings
2023
Induction motors are widely used worldwide for domestic and industrial applications. Fault detection and classification techniques based on signal analysis have increased in popularity due to the growing use of induction motors in new technologies such as electric vehicles, automatic control, maintenance systems, and the inclusion of renewable energy sources in electrical systems, among others. Hence, monitoring, fault detection, and classification are topics of interest for researchers, given that the presence of a fault can lead to catastrophic consequences concerning technical and financial aspects. To detect a fault in an induction motor, several techniques based on different physical variables, such as vibrations, current signals, stray flux, and thermographic images, have been studied. This paper reviews recent investigations into physical variables, instruments, and techniques used in the analysis of faults in induction motors, aiming to provide an overview on the pros and cons of using a certain type of physical variable for fault detection. A discussion about the detection accuracy and complexity of the signals analysis is presented, comparing the results reported in recent years. This work finds that current and vibration are the most popular signals employed to detect faults in induction motors. However, stray flux signal analysis is presented as a promising alternative to detect faults under certain operating conditions where other methods, such as current analysis, may fail.
Journal Article
Macroinvertebrate community structure and ecological status in Portuguese streams across climatic and water scarcity gradients
by
Pereira, Joana Luísa
,
Gonçalves, Fernando J. M
,
Santos, Joana Isabel
in
Aquatic ecosystems
,
Biodiversity
,
Bioindicators
2023
Climatic and hydrological variation is of utmost importance in regions of the globe facing water scarcity and river intermittency (e.g. areas under Mediterranean influence). The main aim of this study was to compare the macroinvertebrate community structure and its bioindicator value (i.e. waterbody ecological status) in streams from three Portuguese regions (Regions C, N and S), representing distinct climatic features and water availability scenarios. Results showed that, overall, sampling sites differed in their climatic, hydromorphological and physical and chemical features, and environmental (abiotic) and ecological (community dissimilarities) gradients among regions were clearly identified. Sites from Regions C (wettest) and S (driest) represented non-overlapping clusters of samples, both in terms of their environmental context and ecological (dis)similarity; sites from Region N occupied an intermediate position, and their macroinvertebrate community was highly variable locally. This coincided with overall higher ecological quality and uniformity in Region C, whereas Regions N and S were more heterogeneous and generally presented lower ecological quality. Our data showed that climate (and associated water scarcity) is coupled with other environmental drivers of the macroinvertebrate community structure, highlighting a shared influence of the three environmental components (climatic, hydromorphological, and physical and chemical) in the modulation of macroinvertebrate communities.
Journal Article
Effects of management practices and socio-physical factors on perennial plant diversity of agroforestry systems of Gedeo landscapes, Southern Ethiopia
2025
This study investigates the influence of agroforestry systems, management practices, and socio-physical factors on plant diversity and richness agroforestry systems of Gedeo in southern Ethiopia. It analyzed 286 sample plots (10 m × 10 m), collecting data on both woody and non-woody perennial species. Insights into management practices and socio-physical conditions were gathered through surveys, focus groups, and interviews. A total of 78 plant species were identified in the study area. The Coffee-Fruit-tree system showed the highest species richness (10 species per plot) and the highest Shannon and Simpson diversity indices. In contrast, the Coffee-Enset-tree and Enset-Tree systems had lower species richness. The study found significant differences in species diversity and abundance across elevations, with highland farms having the lowest values (
p
< 0.001). Plots tilled by hand once a year showed the highest diversity, richness, and abundance, while those ploughed three times a year had the lowest. Weeding once or twice a year did not significantly affect diversity indices, but weeding three times a year reduced them. Wealthier households had higher perennial plant species richness compared to middle-class and poor households. The prevalence of economically focused plants had a detrimental effect on species diversity and richness (
p
< 0.001), whereas selective tree removal had a positive impact on both. Increased frequency of tillage and non-selective weeding by slashing also led to reductions in species diversity and richness. Altitudinal differences had an effect on both species richness and diversity.
Journal Article
Associations between Parents’ Digital Media Habits, Engagement, Awareness, and Movement Guidelines among Preschool-Age Children: International Ipreschooler Surveillance Study
by
Ma, Jiameng
,
Guo, Hongzhi
,
Kim, Hyunshik
in
Child, Preschool
,
Children & youth
,
Comparative analysis
2022
The 24-hour movement guidelines (24-h MG) recommend behaviors (physical activity, screen time, sleep) to aid appropriate physical and mental development in early childhood. This research examined parents’ digital media habits (DMH), engagement (DME), and awareness (DMA) among parents in relation to their preschool-aged children’s 24-h MG in Japan and identified and compared the modifiable determinants of adherence to 24-h MG in urban and rural regions. This cross-sectional study included 867 participants and data were obtained from the International Ipreschooler Surveillance Study Among Asians and OtheRs (IISSAAR). The results revealed that adherence to weekend screen time recommendations and weekday sleep duration were higher in the urban region. The parents’ digital media variables that predicted moderate-intensity to vigorous-intensity physical activity among preschool-aged children were parents’ DME and DMA in the urban regions and parents’ DME in the rural regions. The children’s screen time was significantly associated with parents’ DMH, DME, and DMA in the urban regions and with parents’ DMH and DMA in the rural regions (p < 0.005, p < 0.001, respectively). This study confirmed that parents’ DMH, DME, and DMA are strong predictors of adherence to 24-h MG among preschool-aged children living in both rural and urban regions in Japan.
Journal Article
Knowledge Gaps and Impact of Future Satellite Missions to Facilitate Monitoring of Changes in the Arctic Ocean
by
Korosov, Anton
,
Ferrari, Ramiro
,
Fouchet, Ergane
in
Arctic Ocean
,
Arctic region
,
Artificial satellites in remote sensing
2023
Polar-orbiting satellite observations are of fundamental importance to explore the main scientific challenges in the Arctic Ocean, as they provide information on bio-geo-physical variables with a denser spatial and temporal coverage than in-situ instruments in such a harsh and inaccessible environment. However, they are limited by the lack of coverage near the North Pole (Polar gap), the polar night, and frequent cloud cover or haze over the ocean and sea ice, which prevent the use of optical satellite instruments, as well as by the limited availability of external validation data. The satellite sensors’ coverage and repeat cycles may also have limitations in properly identifying and resolving the dominant spatial and temporal scales of atmospheric, ocean, cryosphere and land variability and their interactive processes and feedback mechanisms. In this paper, we provide a state of the art of contribution of satellite observations to the understanding of the polar environment and climate scientific challenges tackled within the Arktalas Hoavva project funded by the European Space Agency. We identify the current limitations to the wider use of polar orbiting remote sensing data, as well as the observational gaps of the existing satellite missions. A comprehensive overview of all satellite missions and applications is given provided with a primary focus on the European satellites. Finally, we assess the expected capability of the approved future satellite missions to answer today’s scientific challenges in the Arctic Ocean.
Journal Article
Projections of physical conditions in the Gulf of Maine in 2050
by
Pershing, Andrew
,
Brickman, Dave
,
Alexander, Michael A.
in
Acidification
,
Climate change
,
Climate models
2021
The Gulf of Maine (GoM) is currently experiencing its warmest period in the instrumental record. Two high-resolution numerical ocean models were used to downscale global climate projections to produce four estimates of ocean physical properties in the GoM in 2050 for the “business as usual” carbon emission scenario. All simulations project increases in the GoM mean sea surface temperature (of 1.1 °C–2.4 °C) and bottom temperature (of 1.5 °C–2.1 °C). In terms of mean vertical structure, all simulations project temperature increases throughout the water column (surface-to-bottom changes of 0.2 °C–0.5 °C). The GoM volume-averaged changes in temperature range from 1.5 °C to 2.3 °C. Translated to rates, the sea surface temperature projections are all greater than the observed 100-year rate, with two projections below and two above the observed 1982–2013 rate. Sea surface salinity changes are more variable, with three of four simulations projecting decreases. Bottom salinity changes vary spatially and between projections, with three simulations projecting varying increases in deeper waters but decreases in shallower zones and one simulation projecting a salinity increase in all bottom waters. In terms of mean vertical structure, salinity structure varies, with two simulations projecting surface decreases that switch sign with depth and two projecting increases throughout the (subsurface) water column. Three simulations show a difference between coastal and deeper waters whereby the coastal zone is projected to be systematically fresher than deeper waters, by as much as 0.2 g kg–1. Stratification, 50 m to surface, is projected to increase in all simulations, with rates ranging from 0.003 to 0.006 kg m–4 century–1 which are lower than the observed change on the Scotian Shelf. The results from these simulations can be used to assess potential acidification and ecosystem changes in the GoM.
Journal Article
Improved distributed estimation method for environmental physical variables in static sensor networks
by
Khalid, Haris M.
,
Mahmoud, Magdi S.
,
Sabih, Muhammad
in
Algorithms
,
Applied sciences
,
Computer simulation
2013
In this study, an improved distributed estimation scheme for static sensor networks is developed. The scheme is developed for environmental time-variant physical variables. The main contribution of this work is that the algorithm in Saber and Murray (2005), Carli et al. (2009) and Xiao et al. (2004) has been extended, and a filter has been designed with weights, such that the variance of the estimation errors is minimised, thereby improving the filter design considerably and characterising the performance limit of the filter, and thereby tracking a time-varying signal. Moreover, certain parameter optimisation is alleviated with the application of a particular finite impulse response filter. Simulation results are showing the effectiveness of the developed estimation algorithm.
Journal Article
Occupancy of acoustically tagged oceanic manta rays, Mobula birostris, in Bahia de Banderas, Mexico
by
Zavala-Jiménez, Aldo A
,
Kumli, Katherine R
,
Fonseca-Ponce, Iliana A
in
Acoustic telemetry
,
Acoustics
,
Aggregation
2023
The oceanic manta ray (Mobula birostris) is an endangered species commonly seen at oceanic islands and seamounts; however, seasonal aggregations have been described in highly productive, coastal areas. Oceanic manta rays are found in high numbers seasonally in Bahía de Banderas, Mexico, a unique nearshore aggregation site for the species. We used acoustic telemetry to examine the influence of environmental variables on the occurrence of 66 tagged oceanic manta rays over a seven-year period from 2015 to 2021. Seasonal trends in oceanic manta ray occurrence showed a peak in detections from January to March, and another peak from May to early October. Oceanic manta rays were present when the temperature ranged between 25 °C and 29 °C, the southward wind speeds ranged between 3 and 5 m s–1, the westward wind speed between 2.5 and 4.5 m s–1. Furthermore, oceanic manta rays’ presence was higher at high and low tides and when Chlorophyll-a values ranged between 2.5 and 7 mg m3-1. Results also suggest that El Niño Southern Oscillation (ENSO) had a strong effect on oceanic manta ray presence in the bay, which is consistent with previous studies. The detections of oceanic manta rays in the south of the bay, were greater in the morning hours, suggesting that during the night they may move to deeper waters, similar to other reported studies of manta and devil rays. Our model suggested a tag retention time of 300 days. This study serves as a baseline for future management plans for the species to minimize impacts on this population from human activities occurring in close proximity to oceanic manta ray aggregation sites.
Journal Article