Effect of Tendon Vibration on Hemiparetic Arm Stability in Unstable Workspaces

Sensory stimulation of wrist musculature can enhance stability in the proximal arm and may be a useful therapy aimed at improving arm control post-stroke. Specifically, our prior research indicates tendon vibration can enhance stability during point-to-point arm movements and in tracking tasks. The goal of the present study was to investigate the influence of forearm tendon vibration on endpoint stability, measured at the hand, immediately following forward arm movements in an unstable environment. Both proximal and distal workspaces were tested. Ten hemiparetic stroke subjects and 5 healthy controls made forward arm movements while grasping the handle of a two-joint robotic arm. At the end of each movement, the robot applied destabilizing forces. During some trials, 70 Hz vibration was applied to the forearm flexor muscle tendons. 70 Hz was used as the stimulus frequency as it lies within the range of optimal frequencies that activate the muscle spindles at the highest response rate. Endpoint position, velocity, muscle activity and grip force data were compared before, during and after vibration. Stability at the endpoint was quantified as the magnitude of oscillation about the target position, calculated from the power of the tangential velocity data. Prior to vibration, subjects produced unstable, oscillating hand movements about the target location due to the applied force field. Stability increased during vibration, as evidenced by decreased oscillation in hand tangential velocity

Improving route discovery in on-demand routing protocols using local topology information in MANETs

Most existing routing protocols proposed for MANETs use flooding as a broadcast technique for the propagation of network control packets; a particular example of this is the dissemination of route requests (RREQs), which facilitate route discovery. In flooding, each mobile node rebroadcasts received packets, which, in this manner, are propagated network-wide with considerable overhead. This paper improves on the performance of existing routing protocols by reducing the communication overhead incurred during the route discovery process by implementing a new broadcast algorithm called the adjusted probabilistic flooding on the Ad-Hoc on Demand Distance Vector (AODV) protocol. AODV [3] is a well-known and widely studied algorithm which has been shown over the past few years to maintain an overall lower routing overhead compared to traditional proactive schemes, even though it uses flooding to propagate RREQs. Our results, as presented in this paper, reveal that equipping AODV with fixed and adjusted probabilistic flooding, instead, helps reduce the overhead of the route discovery process whilst maintaining comparable performance levels in terms of saved rebroadcasts and reachability as achieved by conventional AODV\@. Moreover, the results indicate that the adjusted probabilistic technique results in better performance compared to the fixed one for both of these metrics

Greenhouses covering materials: a comparative study

Greenhouse covering material is the most governing member of the construction which controls two major parameters, the amount of light and heat diffused from the surrounding environment into the internal space. In hot areas, balancing between optimum temperature and maximum light intensity inside the greenhouse consumes most of the energy spent in vegetable production systems. In this research, a special testing stand was fabricated to simulate the structure of a typical greenhouse provided with a 400W full spectrum light as a source of light and heat. Tests were carried out to investigate the effectiveness of different commercial covering material in light and heat diffusion. Twenty one combinations of Fiberglass, Polyethylene, Polycarbonate, Plexiglass and Agril (PP nonwoven fabric) were tested. It was concluded that Plexiglass was the highest in light transmittance of 87.4%, while the lowest was 33.03% and 34.24% for Fiberglass sheets. The enthalpy of the air moving through the testing rig was calculated according to air temperature differences between inlet and outlet openings. The highest enthalpy value was recorded for one layer of Fiberglass where it was 0.81 kJ/kg air while it was 0.2 kJ/kg air for blocked Plexiglass (60mm)

Impact of Institutional Environment Quality on Tax Evasion: A Comparative Investigation of Old Versus New EU Members

This paper aims at comparatively investigating the impact of institutional environment quality (IEQ) on tax evasion in old (pre-2004) and new (post-2004) European Union (EU) member states. IEQ is measured by the World Bank's Worldwide Governance Indicators, which include voice and accountability, political stability, government effectiveness, regulatory quality, rule of law, and control of corruption. The size of shadow economy is used as a proxy for tax evasion. Using a linear mixed model to analyse the data, the results indicate a higher level of tax evasion in new member states compared to the old ones and reveal that tax evasion is decreasing in the old, albeit at a lower rate compared to the new EU members. Overall, there is evidence that the impact of IEQ on tax evasion is different between the two groups. While regulatory quality, voice and accountability, control of corruption, political stability and government effectiveness are significant determinants of tax evasion levels in older EU members, government effectiveness is the only significant factor in the new EU member states

A Global Forum on Ultramafic Ecosystems: From Ultramafic Ecology to Rehabilitation of Degraded Environments

The 9th International Conference on Serpentine Ecology (ICSE) was held in Tirana and Pogradec (Albania) from June 5 to 9, 2017. More than 100 delegates from 29 countries around the world gathered to present their research on recent advances in: (i) ultramafic soils, (ii) biogeochemistry, (iii) diversity of ultramafic flora, microflora and fauna, (iv) ecophysiology of ultramafic-adapted organisms, (v) interactions between ultramafic organisms and their ecology, (vi) nature rehabilitation of degraded ultramafic environments (resulting from mining activities), and (vii) the production of bio-based metals through agromining technology. Additionally, the ICSE featured the first symposium on ultramafic aquatic ecology and ecotoxicology. Albania has one of the most diverse ultramafic floras in Europe. During the conference delegates visited some of the most emblematic ultramafic sites in Albania as well as the first agromining field trial in Europe. Here, we present the major topics and provide some highlights of the 25 contributions in this Special Issue (Vol. 33 no.3 and 4)