1,951 research outputs found
TEMPORAL METHODS TO ESTIMATE THE DISPLACEMENT OF A CURLING ROCK: COMPARISON BETWEEN COMPETITIVE AND RECREATIONAL CURLERS
The purpose of this study was to examine different methods used in curling to estimate the total rock displacement. A group of competitive (n=8) and recreational (n=8) curlers each delivered a total of 16 rocks, both guards and draws. Interval times for each delivery were measured from the back line to the near hogline and from the near hogline to the far hogline, and the average speed after release and the total rock displacement were determined. Pearson product moment correlations were calculated among the variables for each participant. The results of the study indicated that the various timing methods to estimate the total displacement of the curling rock are appropriate for competitive curlers, but may not provide accurate estimates for all recreational curlers
Anisotropic glass-like properties in tetragonal disordered crystals
The low temperature acoustic and thermal properties of amorphous, glassy
materials are remarkably similar. All these properties are described
theoretically with reasonable quantitative accuracy by assuming that the
amorphous solid contains dynamical defects that can be described at low
temperatures as an ensemble of two-level systems (TLS), but the deep nature of
these TLSs is not clarified yet. Moreover, glassy properties were found also in
disordered crystals, quasicrystals, and even perfect crystals with a large
number of atoms in the unit cell. In crystals, the glassy properties are not
universal, like in amorphous materials, and also exhibit anisotropy. Recently
it was proposed a model for the interaction of two-level systems with arbitrary
strain fields (Phys. Rev. B 75, 64202, 2007), which was used to calculate the
thermal properties of nanoscopic membranes at low temperatures. The model is
also suitable for the description of anisotropic crystals. We describe here the
results of the calculation of anisotropic glass-like properties in crystals of
various lattice symmetries, emphasizing the tetragonal symmetry.Comment: 5 pages, no figure
SKA HI end2end simulation
The current status of the HI simulation efforts is presented, in which a self
consistent simulation path is described and basic equations to calculate array
sensitivities are given. There is a summary of the SKA Design Study (SKADS) sky
simulation and a method for implementing it into the array simulator is
presented. A short overview of HI sensitivity requirements is discussed and
expected results for a simulated HI survey are presented.Comment: 7 pages, 6 figues, need skads2009.cls file to late
Determinants of sustained volunteerism in sport organisations in Hong Kong
Oral presentation: abstract 2014-274INTRODUCTION: The crucial role played by volunteers in sport service delivery is well recognised and documented. However, while there has been considerable research on sport volunteers, most studies have been based typically on theories and samples derived from a western context. This study examined determinants of sustained volunteerism in sport organisations in Hong Kong adapting a theoretical model developed by Penner (2002) …postprin
Scattering of phonons on two-level systems in disordered crystals
We calculate the scattering rates of phonons on two-level systems in
disordered trigonal and hexagonal crystals. We apply a model in which the
two-level system, characterized by a direction in space, is coupled to the
strain field of the phonon via a tensor of coupling constants. The structure of
the tensor of coupling constants is similar to the structure of the tensor of
elastic stiffness constants, in the sense that they are determined by the same
symmetry transformations. In this way, we emphasize the anisotropy of the
interaction of elastic waves with the ensemble of two-level systems in
disordered crystals. We also point to the fact that the ratio
has a much broader range of allowed values in disordered
crystals than in isotropic solids.Comment: 5 pages, no figure
Herbicide impacts on exotic grasses and a population of the critically endangered herb "Calystegia affinis" (Convolvulaceae) on Lord Howe Island
Introduced perennial grasses are capable of altering the habitat of native species, causing reductions in population size and vigour, and potentially affecting life-history processes such as survival, pollination and seedling recruitment. We examined the utility of herbicide treatment on two exotic grasses, Pennisetum clandestinum (Kikuyu) and Stenotaphrum secundatum (Buffalo grass) to restore the habitat of Calystegia affinis, a critically endangered species endemic to Lord Howe and Norfolk Islands. Using two herbicides, Asset (designed to affect only grasses) and Glyphosate (a general herbicide), we compared effectiveness in reducing grass cover on a population of Calystegia affinis. We protected Calystegia plants from the herbicides by ensuring their leaves were covered by plastic bags during herbicide application. Both herbicides were similarly effective in reducing grass cover after four weeks and had no noticeable adverse affect on Calystegia (suggesting the plastic bag protection was effective). After 26 weeks, Glyphosate was more effective in maintaining a reduced grass cover. Plots treated with either herbicide had a greater relative increase in abundance of Calystegia stems compared to untreated controls. The Glyphosate treatment resulted in the greatest relative increase in stem abundance, but this was not significantly greater than in the Asset treatment. We consider that spraying with Glyphosate treatment, with follow-up monitoring and spot-spraying, will assist the recovery of the Calystegia affinis population. Ultimately, the maintenance of a weed-free zone at the forest edge will provide suitable habitat for additional recruitment of this and other native species
Curriculum Development: A Report for the International Baccalaureate Organisation (IBO)
This report examines the development and revision of curricula in jurisdictions, regions and countries round the world. In addition, it provides examples which could further inform the International Baccalaureate Organisation’s (IBO) own curriculum development. We identified thirteen countries and jurisdictions that we thought likely to be productive locations for learning in relation to curriculum development and reform: Finland; Massachusetts, USA; Scotland; Ontario, Canada; Netherlands; Mexico; Germany; England; Chile; Singapore; New Zealand; Victoria, Australia; and Queensland, Australia. Our sources of information included government documents as well as books, and academic and professional journal articles. We collected information about a wide range of issues, from the organization of schooling in these different countries, to the aims and purposes of their curricula, and their arrangements for delivery and assessment
Interaction of Lamb modes with two-level systems in amorphous nanoscopic membranes
Using a generalized model of interaction between a two-level system (TLS) and
an arbitrary deformation of the material, we calculate the interaction of Lamb
modes with TLSs in amorphous nanoscopic membranes. We compare the mean free
paths of the Lamb modes with different symmetries and calculate the heat
conductivity . In the limit of an infinitely wide membrane, the heat
conductivity is divergent. Nevertheless, the finite size of the membrane
imposes a lower cut-off for the phonons frequencies, which leads to the
temperature dependence . This temperature dependence
is a hallmark of the TLS-limited heat conductance at low temperature.Comment: 9 pages, 2 figure
Quantization of the elastic modes in an isotropic plate
We quantize the elastic modes in a plate. For this, we find a complete,
orthogonal set of eigenfunctions of the elastic equations and we normalize
them. These are the phonon modes in the plate and their specific forms and
dispersion relations are manifested in low temperature experiments in
ultra-thin membranes.Comment: 14 pages, 2 figure
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