2,596 research outputs found
BIOMECHANICS AND KINESIOLOGY AT THE UNIVERSITY OF NORTHERN COLORADO
We are all grateful to Professor Jerry Barham for his work in assembling this conference. Those of us at UNC value greatly his professional work and appreciate his effort in bringing this international symposium to Colorado. As a young university, this institution is especially gratified to host such a distinguished event.
This session of the 3rd International Symposium on Biomechanics in Sport allows me to sketch for you a brief history of the kinesiology program--as it is called at the University of Northern Colorado. As you might expect, the preparation for this presentation gave me the opportunity to learn more about the history of the program. I have my suspicions that there are some internal political purposes behind this invitation--to know and better appreciate the program--but that is all well and good. Too seldom do administrators in a university have the opportunity to learn in detail the history of a program and a field. As you know, on most campuses we central administrators are supposedly confined to some tower from which we send edicts--at least that is the mythology. In fact, we are often trapped by demands placed on us by external constituencies such as legislatures and super boards. We came into academia in order to serve our own intellectual interests and ultimately to serve the intellectual interests of our faculty colleagues. And that remains the case for virtually all of us. However, we are often to be found warring over policies imposed and policies to be developed than we are looking at the intellectual aspects of one of the disciplines in the university. For all those reasons, I am pleased to be here and to join you for a little while
Western Governors University: University of the Future
Western Governors University was initiated by Western governors in response to perceived needs in the marketplace and as a supplement to the traditional institutions. WGU offers competency-based credentials at a distance. Students are required to sit for assessments that measure their skills and competencies. The curriculum for each degree is defined by competencies rather than courses. The programs are particularly suited to non-traditional students who are unable to attend residential institutions
Synthetic Molecular Clouds from Supersonic MHD and Non-LTE Radiative Transfer Calculations
The dynamics of molecular clouds is characterized by supersonic random
motions in the presence of a magnetic field. We study this situation using
numerical solutions of the three-dimensional compressible magneto-hydrodynamic
(MHD) equations in a regime of highly supersonic random motions. The non-LTE
radiative transfer calculations are performed through the complex density and
velocity fields obtained as solutions of the MHD equations, and more than
5x10^5 synthetic molecular spectra are obtained. We use a numerical flow
without gravity or external forcing. The flow is super-Alfvenic and corresponds
to model A of Padoan and Nordlund (1997). Synthetic data consist of sets of
90x90 synthetic spectra with 60 velocity channels, in five molecular
transitions: J=1-0 and J=2-1 for 12CO and 13CO, and J=1-0 for CS. Though we do
not consider the effects of stellar radiation, gravity, or mechanical energy
input from discrete sources, our models do contain the basic physics of
magneto-fluid dynamics and non-LTE radiation transfer and are therefore more
realistic than previous calculations. As a result, these synthetic maps and
spectra bear a remarkable resemblance to the corresponding observations of real
clouds.Comment: 33 pages, 12 figures included, 5 jpeg figures not included (fig1a,
fig1b, fig3, fig4 fig5), submitted to Ap
Non-Commutative Inflation
We show how a radiation dominated universe subject to space-time quantization
may give rise to inflation as the radiation temperature exceeds the Planck
temperature. We consider dispersion relations with a maximal momentum (i.e. a
mimimum Compton wavelength, or quantum of space), noting that some of these
lead to a trans-Planckian branch where energy increases with decreasing
momenta. This feature translates into negative radiation pressure and, in
well-defined circumstances, into an inflationary equation of state. We thus
realize the inflationary scenario without the aid of an inflaton field. As the
radiation cools down below the Planck temperature, inflation gracefully exits
into a standard Big Bang universe, dispensing with a period of reheating.
Thermal fluctuations in the radiation bath will in this case generate curvature
fluctuations on cosmological scales whose amplitude and spectrum can be tuned
to agree with observations.Comment: 4 pages, 3 figure
Measuring dark energy spatial inhomogeneity with supernova data
The gravitational lensing distortion of distant sources by the large-scale
distribution of matter in the Universe has been extensively studied. In
contrast, very little is known about the effects due to the large-scale
distribution of dark energy. We discuss the use of Type Ia supernovae as probes
of the spatial inhomogeneity and anisotropy of dark energy. We show that a
shallow, almost all-sky survey can limit rms dark energy fluctuations at the
horizon scale down to a fractional energy density of ~10^-4Comment: 4 pages; PRL submitte
Statistical Determination of Bulk Flow Motions
We present here a new parameterization for the bulk motions of galaxies and
clusters (in the linear regime) that can be measured statistically from the
shape and amplitude of the two-dimensional two-point correlation function. We
further propose the one-dimensional velocity dispersion (v_p) of the bulk flow
as a complementary measure of redshift-space distortions, which is
model-independent and not dependent on the normalisation method. As a
demonstration, we have applied our new methodology to the C4 cluster catalogue
constructed from Data Release Three (DR3) of the Sloan Digital Sky Survey. We
find v_p=270^{+433}km/s (also consistent with v_p=0) for this cluster sample
(at z=0.1), which is in agreement with that predicted for a WMAP5-normalised
LCDM model (i.e., v_p(LCDM=203km/s). This measurement does not lend support to
recent claims of excessive bulk motions (\simeq1000 km/s) which appear in
conflict with LCDM, although our large statistical error cannot rule them out.
From the measured coherent evolution of v_p, we develop a technique to
re-construct the perturbed potential, as well as estimating the unbiased matter
density fluctuations and scale--independent bias.Comment: 8 pages, 5 figure
A detailed analysis of the HD 73526 2:1 resonant planetary system
We present six years of new radial velocity data from the Anglo-Australian and Magellan Telescopes on the HD 73526 2:1 resonant planetary system. We investigate both Keplerian and dynamical ( interacting) fits to these data, yielding four possible configurations for the system. The new data now show that both resonance angles are librating, with amplitudes of 40 degrees and 60 degrees, respectively. We then perform long-term dynamical stability tests to differentiate these solutions, which only differ significantly in the masses of the planets. We show that while there is no clearly preferred system inclination, the dynamical fit with i = 90 degrees provides the best combination of goodness-of-fit and long-term dynamical stability.Peer reviewe
A new concept for the combination of optical interferometers and high-resolution spectrographs
The combination of high spatial and spectral resolution in optical astronomy
enables new observational approaches to many open problems in stellar and
circumstellar astrophysics. However, constructing a high-resolution
spectrograph for an interferometer is a costly and time-intensive undertaking.
Our aim is to show that, by coupling existing high-resolution spectrographs to
existing interferometers, one could observe in the domain of high spectral and
spatial resolution, and avoid the construction of a new complex and expensive
instrument. We investigate in this article the different challenges which arise
from combining an interferometer with a high-resolution spectrograph. The
requirements for the different sub-systems are determined, with special
attention given to the problems of fringe tracking and dispersion. A concept
study for the combination of the VLTI (Very Large Telescope Interferometer)
with UVES (UV-Visual Echelle Spectrograph) is carried out, and several other
specific instrument pairings are discussed. We show that the proposed
combination of an interferometer with a high-resolution spectrograph is indeed
feasible with current technology, for a fraction of the cost of building a
whole new spectrograph. The impact on the existing instruments and their
ongoing programs would be minimal.Comment: 27 pages, 9 figures, Experimental Astronomy; v2: accepted versio
Grain Boundaries in Graphene on SiC(000) Substrate
Grain boundaries in epitaxial graphene on the SiC(000) substrate are
studied using scanning tunneling microscopy and spectroscopy. All investigated
small-angle grain boundaries show pronounced out-of-plane buckling induced by
the strain fields of constituent dislocations. The ensemble of observations
allows to determine the critical misorientation angle of buckling transition
. Periodic structures are found among the flat
large-angle grain boundaries. In particular, the observed highly ordered grain boundary is assigned to the previously
proposed lowest formation energy structural motif composed of a continuous
chain of edge-sharing alternating pentagons and heptagons. This periodic grain
boundary defect is predicted to exhibit strong valley filtering of charge
carriers thus promising the practical realization of all-electric valleytronic
devices
Skeletal maturity and socio-economic status in portuguese children and youths: the Madeira growth study
Skeletal maturity is used to evaluate biological maturity status. Information about the association between socio-economic status (SES) and skeletal maturity is limited in Portugal. Aims: The aim of this study is to document the skeletal maturity of youths in Madeira and to evaluate variation in maturity associated with SES. Subjects and methods: The study involved 507 subjects (256 boys and 251 girls) from the Madeira Growth Study, a mixed-longitudinal study of five cohorts (8, 10, 12, 14 and 16 years of age) followed at yearly intervals over 3 years (1996–1998). A total of 1493 observations were made. Skeletal age was estimated from radiographs of the hand and wrist using the Tanner–Whitehouse 2 method (TW2). Social class rankings were based on Graffar’s (1956) method. Five social rankings were subsequently grouped into three SES categories: high, average and low. Results: Median for the radius, ulna and short finger bones (RUS scores) in the total sample of boys and girls increased curvilinearly across age whereas median for the 7 (without pisiform) carpal bones (Carpal scores) increased almost linearly. The 20-bone maturity scores demonstrated distinctive trends by gender: the medians for boys increased almost linearly while the medians for girls increased curvilinearly. SES differences were minimal. Only among children aged 10–11 years were high SES boys and girls advanced in skeletal maturity. Madeira adolescents were advanced in skeletal maturity compared with Belgian reference values. Conclusion: The data suggests population variation in TW2 estimates of skeletal maturation. Skeletal maturity was not related to SES in youths from Madeira
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