TRAINING AND EXPERIENCE ATTENUATE PROTECTIVE GAIT STRATEGIES DURING BEAM WALKING

Walking on a narrow, raised beam is more difficult than walking across a floor. During beam walking, a protective strategy designed to maximise stability is adopted. This study compared the electrical activity (EMG) of selected leg muscles during normal walking with that during beam walking in novice and expert subjects. Results show that whilst changes (compared with normal walking) occurred in all subjects during beam walking, the magnitude of these changes is less in experts than in novices. In particular experts showed reduced muscle co-contraction during beam walking than novices. Thus whilst a protective strategy is elicited in expert subjects, the extent to which it is manifest is reduced. Experts maintain more typical patterns of EMG and should be less prone to muscle fatigue, a factor known to increase the risk of injury

Non-hydrostatic effects on mountain wave breaking in directional shear flows

Mountain waves excited by narrow 3D orography are investigated using idealized numerical simulations of atmospheric flows with directional wind shear. The stability of these waves is compared with the stability of hydrostatic mountain waves. The focus is on understanding how wave breaking is modified via gravity wave-critical level interaction, when non-hydrostatic (dispersive) effects arise. The influence of nonhydrostatic effects on wave breaking appears to be a function of the intensity of the background shear, increasing the stability of the flow (inhibiting wave breaking) for weak wind shear, but decreasing it instead (enhancing wave breaking) for stronger wind shear

Some factors affecting the feeding ecology and socio-biology of the samango monkey, cercopithecus albogularis schwarzi roberts, 1931

In an attempt to explain why forest monkeys have a one-male group type of social structure in an environment of apparently rich food supply, the food resources, feeding behaviour and ranging behaviour of the samango monkey was studied in forest on the Eastern Transvaal Escarpment. The taxonomy of the samango monkey in southern africa is discussed, as well as it•s relationship to other forest Cercopithecines. The adaptations and limitations of the animal •s intrinsic characteristics in a forest environment are discussed. By a detailed analysis of climatic, microclimatic, phytosociological and phenological data the nature of the habitat as a whole was enumerated. Climatic parameters of the study area were compared to other areas inhabited by close relations of the samango monkey and the study area was found to be highly unstable in comparison to them. The forest itself was found to exercise a buffering effect on all meteors examined, thus modulating this instability to a degree. The forest areas used by the monkeys were of mixed dominance and could be divided by qualitative methods into distinct vegetational zones. Phenologically the trees were found to be highly irregular in time, duration and amount of production of a given phytophase. Almost all identified species in the study area were found to be used by the monkeys as a source of food. Several samango food items were weighed and measured and their food values determined. The effect of palatability and ease of obtaining and preparing food items is discussed. From this enumeration of the forest as a habitat it was found that contrary to popular belief forest is in fact a highly irregular and variable provider of food, indicating that the monkeys may indeed suffer from a form of food stress, albeit not in the same way that a gelada baboon does. In the last section the response of the monkeys in their social structure, ranging behaviour and activity patterns is discussed. Aspects of all of these were seen to show adaptations to this variable and uncertain environment.Dissertation (MSc)--University of Pretoria, 1980.Zoology and EntomologyMScUnrestricte

Orographic drag associated with lee waves trapped at an inversion

The drag produced by 2D orographic gravity waves trapped at a temperature inversion and waves propagating in the stably stratified layer existing above are explicitly calculated using linear theory, for a two-layer atmosphere with neutral static stability near the surface, mimicking a well-mixed boundary layer. For realistic values of the flow parameters, trapped lee wave drag, which is given by a closed analytical expression, is comparable to propagating wave drag, especially in moderately to strongly non-hydrostatic conditions. In resonant flow, both drag components substantially exceed the single-layer hydrostatic drag estimate used in most parametrization schemes. Both drag components are optimally amplified for a relatively low-level inversion and Froude numbers Fr ≈ 1. While propagating wave drag is maximized for approximately hydrostatic flow, trapped lee wave drag is maximized for l_2 a = O(1) (where l_2 is the Scorer parameter in the stable layer and a is the mountain width). This roughly happens when the horizontal scale of trapped lee waves matches that of the mountain slope. The drag behavior as a function of Fr for l_2 H = 0.5 (where H is the inversion height) and different values of l2a shows good agreement with numerical simulations. Regions of parameter space with high trapped lee wave drag correlate reasonably well with those where lee wave rotors were found to occur in previous nonlinear numerical simulations including frictional effects. This suggests that trapped lee wave drag, besides giving a relevant contribution to low-level drag exerted on the atmosphere, may also be useful to diagnose lee rotor formation

Wake Vortex Pair Formation as an Analog for Dust Devil and Tornado Genesis

In 1966, meteorologist R.S. Scorer attempted to explain how large-scale oceanic tropical depressions become hurricanes or typhoons. His model was based on the idea that when these large-scale tropical depression structures begin to rotate, mostly due to Coriolis effects, an annular outer portion of that structure changes suddenly to a potential vortex segment, with the same outer radial limit as the low-pressure structure, but with an inner radius that conserves the overall system angular momentum and kinetic energy. By analogy with the jump instability describing sudden buckling of a vertical column, this paper shows that his conjecture merits additional consideration. If valid, the Scorer model implies that the controlling large scale flow is essentially an inviscid Rankine vortex. While hurricanes can sustain this Rankine vortex eye structure over warm ocean, over land smaller-scale tornadoes and dust devils cannot draw from a similar sustaining energy source. Scorer\u27s model implies that, without additional energy, the outer inviscid vortex region should force the rotating inner cylindrical region to collapse as the overall inviscid structure proceeds toward the rotational axis. That vortex evolution requires additional energy- from an unknown source. This paper utilizes Scorer\u27s finite vortex domain hypothesis on an evolving aircraft wake vortex pair, and his assertion that the inviscid vortex pair is the controlling flow, to generate turbulent non-equilibrium vortex cores and by extension explain how tornadoes and dust devils form from rotating atmosphere

Drag associated with 3D trapped lee waves over an axisymmetric obstacle in two-layer atmospheres

Mountain wave drag is evaluated explicitly using linear theory and verified against numerical simulations for the flow of idealized two-layer atmospheres with piecewise-constant stratification over an axisymmetric mountain. Static stability is either higher in the bottom layer and lower in the top layer (Scorer's atmosphere), or neutral in the bottom layer and positive in the top layer, separated by a sharp temperature inversion (Vosper's atmosphere). The drag receives contributions from long mountain waves propagating vertically in the upper layer and from short trapped lee waves propagating downstream either in the lower layer, or at the inversion. This trapped lee wave drag, which is typically not represented in parametrizations, acts on the atmosphere at low levels. As in flow over a 2D ridge, this drag has several maxima as a function of the height of the interface between the two layers for Scorer's atmosphere, and is maximized by a marked Scorer parameter contrast between those layers. In Vosper's atmosphere, there is a single trapped lee wave drag maximum for Froude numbers near one, when the wind speed matches the phase speed of the dominant interfacial waves, and this drag is maximized for relatively low interface elevations, for which waves at the inversion have higher amplitude. The 3D flow geometry allows resonant wave modes to have various horizontal orientations and a continuous spectrum, forming a dispersive ‘Kelvin ship wave' pattern, and expanding the regions in parameter space where the drag is non-zero relative to 2D flow, but it also dispersively decreases the drag magnitude. Nevertheless, the trapped lee wave drag on an axisymmetric obstacle can still equal or exceed the drag associated with vertically propagating waves and the reference hydrostatic drag valid for a uniformly stratified atmosphere

Mapping the undergraduate dermatology curriculum – a useful tool towards implementation of national recommendations

Despite the high prevalence of skin complaints in primary and secondary care, dermatology undergraduate (UG) education remains inconsistent across medical schools. The British Association of Dermatologists (BAD) published a revised national undergraduate curriculum in 2016 to guide UK medical schools on minimum competencies required in dermatology. A curriculum mapping study was conducted to determine the alignment of the BAD UG curriculum with the dermatology curriculum of the University of Nottingham (UoN) School of Medicine. Of the 70 intended learning outcomes (ILOs) for dermatology in the medical school, 55 (79%) were mapped to the BAD curriculum, 14 (20%) required modifications to align them with the BAD ILOs, 2 BAD outcomes were unspecified in the current curriculum, and 1 outcome overlapped with others and was deemed redundant. Curriculum mapping is a useful tool to standardise local dermatology ILOs to national recommendations and provides transparency to stakeholders for implementation of the dermatology curriculum

Remote Rhythms: Audience-informed insights for designing remote music performances

This paper examines the design of technology for remote music performances, from the perspective of their audiences. In this process, we involved a total of 104 participants across the different stages of our project. Initially, we collected qualitative data from remote audiences using several methods, including surveys, interviews, and observations. Through the thematic analysis of this data, we identified four design dimensions consisting of 17 key elements that illustrate what audiences value in remote music spaces. We applied these insights in a participatory design workshop with diverse stakeholders, contributing to the development of speculative design ideas in this field. The paper concludes by presenting key design insights for future technology advancements in remote music performances. The research contributes to the evolving design space of remote music performances, offering valuable perspectives for researchers, designers, and industry stakeholders