854 research outputs found

    To sit or stand? A preliminary, cross sectional study to investigate if there is a difference in glenohumeral subluxation in sitting or standing in people following stroke

    Get PDF
    Background: Glenohumeral subluxation (GHS) is a common symptom following stroke. Many therapists postulate that GHS may be reduced if the base of support (BOS) is reduced and the centre of mass (COM) is raised as this requires greater postural muscle activity. However, there is little empirical evidence to support this practice. Objective: The aim of this preliminary study was to investigate if the amount of GHS alters from sitting to standing. Study design: A cross sectional, within-subject design in a convenience sample of 15 stroke patients with GHS was utilised. Methods: A prospective design was used with a single blinded tester who assessed GHS using the calliper method in sitting, standing and on return to sitting. Friedman and post hoc Wilcoxon tests showed that GHS was significantly reduced in standing compared to sitting (p <0.05) but this reduction was not maintained on return to sitting (p = 0.25). Conclusions: The results of this study are limited by its small size. However, these results indicate that reducing BOS during rehabilitation may improve GHS after stroke. Whilst the maintenance of benefit is not established, these findings suggest that reducing BOS as part of treatment may help patients with GHS. Further research is now required to replicate these results in a larger sample and to directly examine shoulder muscle activity to investigate which muscles may influence GHS in response to changing BOS. Future work could also aim to determine whether the reduction in GHS was directly attributable to a reduced BOS or the effort associated with moving from sitting to standing

    Counter-current chromatography for the separation of terpenoids: A comprehensive review with respect to the solvent systems employed

    Get PDF
    Copyright @ 2014 The Authors.This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.Natural products extracts are commonly highly complex mixtures of active compounds and consequently their purification becomes a particularly challenging task. The development of a purification protocol to extract a single active component from the many hundreds that are often present in the mixture is something that can take months or even years to achieve, thus it is important for the natural product chemist to have, at their disposal, a broad range of diverse purification techniques. Counter-current chromatography (CCC) is one such separation technique utilising two immiscible phases, one as the stationary phase (retained in a spinning coil by centrifugal forces) and the second as the mobile phase. The method benefits from a number of advantages when compared with the more traditional liquid-solid separation methods, such as no irreversible adsorption, total recovery of the injected sample, minimal tailing of peaks, low risk of sample denaturation, the ability to accept particulates, and a low solvent consumption. The selection of an appropriate two-phase solvent system is critical to the running of CCC since this is both the mobile and the stationary phase of the system. However, this is also by far the most time consuming aspect of the technique and the one that most inhibits its general take-up. In recent years, numerous natural product purifications have been published using CCC from almost every country across the globe. Many of these papers are devoted to terpenoids-one of the most diverse groups. Naturally occurring terpenoids provide opportunities to discover new drugs but many of them are available at very low levels in nature and a huge number of them still remain unexplored. The collective knowledge on performing successful CCC separations of terpenoids has been gathered and reviewed by the authors, in order to create a comprehensive document that will be of great assistance in performing future purifications. © 2014 The Author(s)

    A New Acquisition Scheme of a DS/SS Signal with Transmit and Receive Antenna Diversity

    Get PDF
    In this paper, we propose the introduction of space diversity techniques to the code acquisition of a direct-sequence spread-spectrum signal. In this scheme, both a transmitter and a receiver have multiple antennas and the signats corresponding to all the combinations of the transmitter/receiver antennas are combined at the acquisition circuit of the receiver. The performance is evaluated for indoor packet radio corn. munication systems from the viewpoints of average time for acquisition, probahitity of success of acquisition, and necessary preamble length. As the result, we show great performance improvements by the proposed scheme under slow and flat Rayleigh fading environment.journal articl

    Acquisition of a DS/SS Signal with Macro/Micro Antenna Diversity under Rayleigh Fading and Log-normal Shadowing

    Get PDF
    In this paper, we propose the introduction of space diversity techniques to the code acquisition of an indoor packet radio communication system with direct-sequence spread-spectrum technique. In the proposed scheme, the base station has several radio ports each with a cluster of antennas, and the mobile station also has multiple antennas. As the result. We show great performance improvements by the proposed scheme under slow and flat Rayleigh fading and log-normal shadowing environment.journal articl

    Performance of the ATLAS trigger system in 2015

    Get PDF
    During 2015 the ATLAS experiment recorded 3.8fb−1 of proton–proton collision data at a centre-of-mass energy of 13TeV. The ATLAS trigger system is a crucial component of the experiment, responsible for selecting events of interest at a recording rate of approximately 1 kHz from up to 40 MHz of collisions. This paper presents a short overview of the changes to the trigger and data acquisition systems during the first long shutdown of the LHC and shows the performance of the trigger system and its components based on the 2015 proton–proton collision data

    Pacing and Decision Making in Sport and Exercise: The Roles of Perception and Action in the Regulation of Exercise Intensity

    Get PDF
    In pursuit of optimal performance, athletes and physical exercisers alike have to make decisions about how and when to invest their energy. The process of pacing has been associated with the goal-directed regulation of exercise intensity across an exercise bout. The current review explores divergent views on understanding underlying mechanisms of decision making in pacing. Current pacing literature provides a wide range of aspects that might be involved in the determination of an athlete's pacing strategy, but lacks in explaining how perception and action are coupled in establishing behaviour. In contrast, decision-making literature rooted in the understanding that perception and action are coupled provides refreshing perspectives on explaining the mechanisms that underlie natural interactive behaviour. Contrary to the assumption of behaviour that is managed by a higher-order governor that passively constructs internal representations of the world, an ecological approach is considered. According to this approach, knowledge is rooted in the direct experience of meaningful environmental objects and events in individual environmental processes. To assist a neuropsychological explanation of decision making in exercise regulation, the relevance of the affordance competition hypothesis is explored. By considering pacing as a behavioural expression of continuous decision making, new insights on underlying mechanisms in pacing and optimal performance can be developed. © 2014 Springer International Publishing Switzerland

    Microstructure of non-polar GaN on LiGaO2 grown by plasma-assisted MBE

    Get PDF
    We have investigated the structure of non-polar GaN, both on the M - and A-plane, grown on LiGaO2 by plasma-assisted molecular beam epitaxy. The epitaxial relationship and the microstructure of the GaN films are investigated by transmission electron microscopy (TEM). The already reported epi-taxial relationship and for M -plane GaN is confirmed. The main defects are threading dislocations and stacking faults in both samples. For the M -plane sample, the density of threading dislocations is around 1 × 1011 cm-2 and the stacking fault density amounts to approximately 2 × 105 cm-1. In the A-plane sample, a threading dislocation density in the same order was found, while the stacking fault density is much lower than in the M -plane sample

    Evaluation of Finger Direction Recognition Method for Behavior Control of Robot

    Get PDF
    Abstract When a human gives an order to a robot, the robot must often use its vision to ascertain the human’s indication. In our previous paper, to develop a system where robots precisely receive and obey human orders in daily work spaces, we proposed an experimental system for finger direction recognition (FDR) in 3D space using stereo matching by mounting two cameras on the robot. In this paper, we evaluate this system for FDR in 3D space by performing a series of evaluation experiments using a turntable capable of fixing a hand in a specific finger direction. We estimated various finger directions and distances for two major pointing hand forms (Forms 1 and 2) and evaluated the precision of θ and Φ. We conclude that the θ and Φ estimations are valid because the estimation error is almost within 10 ° when the distance between the camera and object is less than 110 and 80 cm for θ and Φ for Forms 1 and 2, respectively. Finally, we applied our FDR system to the communication between a robot and a person by visual and tactile sensations. In the application test, the robot recognized the object at which the person pointed and put it in the person’s palm.</jats:p
    corecore