The measurement of biaxial strains in coated fabric materials using the disc-replica method

A method of measuring biaxial strains in coated fabric type materials is presented whereby the strain is deduced from the distortion of a circular impression made on the material. The impression is placed on the material when loaded, enabling all measurements to be made with the material in its relaxed, unloaded, state

The effect of parallel static and microwave electric fields on excited hydrogen atoms

Motivated by recent experiments we analyse the classical dynamics of a hydrogen atom in parallel static and microwave electric fields. Using an appropriate representation and averaging approximations we show that resonant ionisation is controlled by a separatrix, and provide necessary conditions for a dynamical resonance to affect the ionisation probability. The position of the dynamical resonance is computed using a high-order perturbation series, and estimate its radius of convergence. We show that the position of the dynamical resonance does not coincide precisely with the ionisation maxima, and that the field switch-on time can dramatically affect the ionisation signal which, for long switch times, reflects the shape of an incipient homoclinic. Similarly, the resonance ionisation time can reflect the time-scale of the separatrix motion, which is therefore longer than conventional static field Stark ionisation. We explain why these effects should be observed in the quantum dynamics. PACs: 32.80.Rm, 33.40.+f, 34.10.+x, 05.45.Ac, 05.45.MtComment: 47 pages, 20 figure

Initiating technical refinements in high-level golfers: Evidence for contradictory procedures

When developing motor skills there are several outcomes available to an athlete depending on their skill status and needs. Whereas the skill acquisition and performance literature is abundant, an under-researched outcome relates to the refinement of already acquired and well-established skills. Contrary to current recommendations for athletes to employ an external focus of attention and a representative practice design, Carson and Collins’ (2011) [Refining and regaining skills in fixation/diversification stage performers: The Five-A Model. International Review of Sport and Exercise Psychology, 4, 146–167. doi:10.1080/1750984x.2011.613682] Five-A Model requires an initial narrowed internal focus on the technical aspect needing refinement: the implication being that environments which limit external sources of information would be beneficial to achieving this task. Therefore, the purpose of this paper was to (1) provide a literature-based explanation for why techniques counter to current recommendations may be (temporarily) appropriate within the skill refinement process and (2) provide empirical evidence for such efficacy. Kinematic data and self-perception reports are provided from high level golfers attempting to consciously initiate technical refinements while executing shots onto a driving range and into a close proximity net (i.e. with limited knowledge of results). It was hypothesised that greater control over intended refinements would occur when environmental stimuli were reduced in the most unrepresentative practice condition (i.e. hitting into a net). Results confirmed this, as evidenced by reduced intra-individual movement variability for all participants’ individual refinements, despite little or no difference in mental effort reported. This research offers coaches guidance when working with performers who may find conscious recall difficult during the skill refinement process

“To hit, or not to hit?” Examining the similarity between practice and real swings in golf

Practice swings are commonly employed among golfers, presumably based on the tacit assumption that they share common psychomotor processes with real swings; however, this has not been verified by empirical research. Therefore, this study aimed to examine whether practice swings shared equivalent levels of control to real golf swings, when attempting the same target behavior. Three PGA Professional golf coaches and six amateurs (mean handicap = 2.7, SD = 2.2) each executed 20 swings under two quasirandom conditions; 10 real swings when striking a ball and 10 practice swings without. Underpinned by the theoretical suggestions of the UnControlled Manifold (UCM) approach (Scholz & Schöner, 1999), motor control was assessed using intraindividual movement variability. Results showed the level of equivalence to be inconsistent on both an inter and intraindividual basis. Coaches should, therefore, recognize that practice swings do not share the same effect for every golfer. Optimal coaching needs to consider individual responses before committing to specific training designs if counterproductive training is to be avoided

Laserlight visual cueing device for freezing of gait in Parkinson's disease: a case study of the biomechanics involved

AbstractBackground: Freezing of gait (FOG) is a serious gait disorder affecting up to two-thirds of people with Parkinson's disease (PD). Cueing has been explored as a method of generating motor execution using visual transverse lines on the floor. However, the impact of a laser light visual cue remains unclear. Objective: To determine the biomechanical effect of a laser cane on FOG in a participant with PD compared to a healthy age- and gender-matched control. Methods: The participant with PD and healthy control were given a task of initiating gait from standing. Electromyography (EMG) data were collected from the tibialis anterior (TA) and the medial gastrocnemius (GS) muscles using an 8-channel system. A 10-camera system (Qualisys) recorded movement in 6 degrees of freedom and a calibrated anatomical system technique was used to construct a full body model. Center of mass (COM) and center of pressure (COP) were the main outcome measures. Results: The uncued condition showed that separation of COM and COP took longer and was of smaller magnitude than the cued condition. EMG activity revealed prolonged activation of GS, with little to no TA activity. The cued condition showed earlier COM and COP separation. There was reduced fluctuation in GS, with abnormal, early bursts of TA activity. Step length improved in the cued condition compared to the uncued condition. Conclusion: Laserlight visual cueing improved step length beyond a non-cued condition for this patient indicating improved posture and muscle control

Project Tech Top study of lunar, planetary and solar topography Final report

Data acquisition techniques for information on lunar, planetary, and solar topograph

Tm3+/Ho3+ codoped tellurite fiber laser

Continuous-wave and Q-switched lasing from a Tm 3+ /Ho 3+ codoped tellurite fiber is reported. An Yb 3+ /Er 3+ -doped silica fiber laser operating at 1.6μm was used as an in-band pump source, exciting the Tm 3+ ions into the F 4 3 level. Energy is then nonradiatively transferred to the upper laser level, the I 7 5 state of Ho 3+ . The laser transition is from the I 7 5 level to the I 8 5 level, and the resulting emission is at 2.1μm . For continuous wave operation, the slope efficiency was 62% and the threshold 0.1W ; the maximum output demonstrated was 0.16W . Mechanical Q switching resulted in a pulse of 0.65μJ energy and 160ns duration at a repetition rate of 19.4kHz

College of occupational therapists: Position paper on the way ahead for research, education and practice in mental health

The future of occupational therapy in mental health has been a topic of reflection and debate. The Education and Research Board (now the Education and Practice Board) of the College of Occupational Therapists created a Working Group to develop a position paper on the way ahead for research, education and practice in mental health. Following consultation, the Working Group reviewed literature, examined current research and surveyed practitioners, managers and educators. From these findings, recommendations have been made which will lead to a firmer evidence base for the practice of occupational therapy in mental health, leading to a more effective use of the expertise of occupational therapists and an improved service for users