The influence of visual flow and perceptual load on locomotion speed

Visual flow is used to perceive and regulate movement speed during locomotion. We assessed the extent to which variation in flow from the ground plane, arising from static visual textures, influences locomotion speed under conditions of concurrent perceptual load. In two experiments, participants walked over a 12-m projected walkway that consisted of stripes that were oriented orthogonal to the walking direction. In the critical conditions, the frequency of the stripes increased or decreased. We observed small, but consistent effects on walking speed, so that participants were walking slower when the frequency increased compared to when the frequency decreased. This basic effect suggests that participants interpreted the change in visual flow in these conditions as at least partly due to a change in their own movement speed, and counteracted such a change by speeding up or slowing down. Critically, these effects were magnified under conditions of low perceptual load and a locus of attention near the ground plane. Our findings suggest that the contribution of vision in the control of ongoing locomotion is relatively fluid and dependent on ongoing perceptual (and perhaps more generally cognitive) task demands

Drying colloidal systems: laboratory models for a wide range of applications

The drying of complex fluids provides a powerful insight into phenomena that take place on time and length scales not normally accessible. An important feature of complex fluids, colloidal dispersions and polymer solutions is their high sensitivity to weak external actions. Thus, the drying of complex fluids involves a large number of physical and chemical processes. The scope of this review is the capacity to tune such systems to reproduce and explore specific properties in a physics laboratory. A wide variety of systems are presented, ranging from functional coatings, food science, cosmetology, medical diagnostics and forensics to geophysics and art

Comparison of a minimally invasive posterior approach and the standard posterior approach for total hip arthroplasty A prospective and comparative study

Abstract Background It is not clear whether total hip arthroplasty performed via a minimally invasive approach leads to less muscle trauma compared to the standard approach. Materials and methods To investigate whether a minimally invasive posterior approach for total hip arthroplasty results in lower levels of muscle-derived enzymes and better post-operative clinical results than those obtained with the standard posterolateral approach fifty patients in both groups were compared in a prospective and comparative study. The following parameters were examined: muscle-derived enzymes CPK, CK-MM and myoglobin pre-operatively, 24 and 48 hours post-operatively, CRP and hemoglobin on the third postoperative day, loss of blood, daily pain levels, the rate of recovery (time taken to attain predefined functional parameters), the Oxford Hip Score, the SF-36 score and the WOMAC score pre-operatively and six weeks post-surgery, the position of the implant and the cement coating by post-operative X-ray examination. Results and Conclusions The minimally invasive operated patients exhibited a significantly lower loss of blood, significantly less pain at rest and a faster rate of recovery but the clinical chemistry values and the other clinical parameters were comparable.</p