Search results for "Acceleration"
showing 10 items of 345 documents
Pushing the Limit – MRI of the Lung Using Hyperpolarized 3-Helium in Conjunction with Parallel Imaging
2009
Imaging of the lung with hyperpolarized 3He became a well known technique in the last decade. Being able to image ventilation and the microstructure of the lung an increase of SNR and a shortage of scan time is eligible. By using a 32-channel phased array the sensitivity was increased dramatically. High resolution 2D-images with a resolution of 1 × 1 mm2 having a 3 mm slice was realized, showing highly detailed images of the lung. By applying parallel imaging techniques the SNR could be increased and scan time was reduced drastically by using a 2D acceleration of R = 4 × 2 with a 3D-protocol covering the whole lung.
Multimessenger search for sources of gravitational waves and high-energy neutrinos: Initial results for LIGO-Virgo and IceCube
2014
Made available in DSpace on 2022-04-29T07:21:49Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-11-17 We report the results of a multimessenger search for coincident signals from the LIGO and Virgo gravitational-wave observatories and the partially completed IceCube high-energy neutrino detector, including periods of joint operation between 2007-2010. These include parts of the 2005-2007 run and the 2009-2010 run for LIGO-Virgo, and IceCube's observation periods with 22, 59 and 79 strings. We find no significant coincident events, and use the search results to derive upper limits on the rate of joint sources for a range of source emission parameters. For the optimistic assumption of …
A Novel System for Measuring Damaging Impacts on Table Olives
2015
The consumer today demands high quality products; fruit with defects or in poor condition generate dissatisfaction and a consequent reduction in consumption. In recent years, interesting systems have been used (i. e. "artificial fruit") in order to identify the cause of damage during mechanical harvesting and/or post-harvest operations. In this paper, the authors present a new system designed to measure the impacts received by table olives in the processing stages from harvesting to packaging. The device is an instrumented sphere designed and implemented by the Agricultural Mechanics Section of the Department of Agricultural and Forest Sciences, University of Palermo, Italy. It contains a t…
Variability and Symmetry of Force Platform Variables in Maximum-Speed Running in Young and Older Athletes
2010
Eighteen young (23 ± 4 yr) and 25 older (70 ± 4 yr) male sprinters were examined for ground reaction force (GRF) and temporal-spatial variables. The data were collected during maximum-speed phase, and variability and symmetry indices were calculated from a total of 8 steps. There was little variation (CV < 6%) in vertical and resultant GRF and kinematic variables, while impact loading had high variability (CV: 10–21%). Overall, the pattern of variability was similar in both groups. Yet, a small but significant age-related increase in CV was evident in horizontal GRFs. There was a variable-specific asymmetry between legs but it was not related to leg dominance. No age differences existed …
Comparison of motor strategies in sit-to-stand and back-to-sit motions between healthy and Alzheimer’s disease elderly subjects
2005
We studied the kinematics of shoulder displacement during sit-to-stand and back-to-sit in 6 healthy elderly subjects and six elderly subjects with mild to moderate Alzheimer's disease in order to elucidate the impact of Alzheimer's disease on motor planning and control processes. During sit-to-stand, Alzheimer's disease subjects reduced their forward displacement and started their upward displacement earlier than healthy elderly subjects. Furthermore, shoulder path curvatures were more pronounced for upward compared with downward displacement in healthy elderly group, in contrast with Alzheimer's disease group. Temporal analysis found that: 1) for both groups, profiles of velocity of sit-to…
Influence of competition on performance factors in under-19 soccer players at national league level.
2020
The aim of this study was to analyse and quantify the acute effects of competition on several performance factors in under-19 male soccer players. To this end, 198 national league players (17.56 ± 0.78 years) performed various tests to measure jump capacity, kicking velocity and sprint times immediately pre-match (T1), at half-time (T2) and post-match (T3). Tests included kicking the ball to measure ball velocity (KICK), sprinting for 40 meters, timing the first 30 meters (30mACCEL), the last 10 meters (10mACCEL) and the total distance (40mACCEL), and performing countermovement jumps (CMJ). For subsequent analysis, the sample was divided into 5 playing positions: goalkeepers (n = 24), defen…
Naturalistic music and dance: Cortical phase synchrony in musicians and dancers
2018
Expertise in music has been investigated for decades and the results have been applied not only in composition, performance and music education, but also in understanding brain plasticity in a larger context. Several studies have revealed a strong connection between auditory and motor processes and listening to and performing music, and music imagination. Recently, as a logical next step in music and movement, the cognitive and affective neuro-sciences have been directed towards expertise in dance. To understand the versatile and overlapping processes during artistic stimuli, such as music and dance, it is necessary to study them with continuous naturalistic stimuli. Thus, we used long exce…
Age, training, and previous experience predict race performance in long-distance inline skaters, not anthropometry
2012
Knechtle, Beat | Knechtle, Patrizia | Ruest, Christoph Alexander | Rosemann, Thomas | Lepers, Romuald; International audience; ''The association of characteristics of anthropometry, training, and previous experience with race time in 84 recreational, long-distance, inline skaters at the longest inline marathon in Europe (111 km), the Inline One-eleven in Switzerland, was investigated to identify predictor variables for performance. Age, duration per training unit, and personal best time were the only three variables related to race time in a multiple regression, while none of the 16 anthropometric variables were related. Anthropometric characteristics seem to be of no importance for a fast …
Measuring threshold and latency of motion perception on a swinging bed.
2020
Introduction Our objective was to develop and to evaluate a system to measure latency and threshold of pendular motion perception based on a swinging bed. Materials and methods This prospective study included 30 healthy adults (age: 32 ± 12 years). All subjects were tested twice with a 10 min. interval. A second trial was conducted 2 to 15 days after. A rehabilitation swinging bed was connected to an electronic device emitting a beep at the beginning of each oscillation phase with an adjustable time lag. Subjects were blindfolded and auditory cues other than the beep were minimized. The acceleration threshold was measured by letting the bed oscillate freely until a natural break and asking…
Accelerometer-assessed sedentary work, leisure time and cardio-metabolic biomarkers during one year : Effectiveness of a cluster randomized controlle…
2017
BackgroundIt is unknown whether reducing sedentary time at work and during leisure time is possible and effective during one year.MethodsOffice workers with young children were recruited for this one-year cluster-randomized controlled trial through kindergartens and primary schools from 7 clusters in the city of Jyväskylä, Finland. After a lecture, face-to-face tailored counseling was used to set contractually binding goals regarding reducing and breaking up sitting periods and increasing light intensity physical activity during work and leisure time. Primary outcomes of total, work and leisure sedentary time (ResultsParticipants from intervention (N = 71) and control (N = 62) regions were …