2,051 research outputs found
Athletic Department Practices Related to the Academic Performance and Persistence of Student-Athletes
This research project applies student academic performance and persistence findings presented by A. Astin and V. Tinto to the practices of intercollegiate athletic departments and their relationships with faculty and student-athletes. Through survey research of 178 football and men's basketball players, athletic administration, coaches, and faculty in Division I athletic programs, including cross tabulation and frequency analysis of data, this study examined athletic department practices related to the academic performance and persistence of the student-athletes. Four parallel convenience samples were identified and surveyed during this study. The student-athlete sample (N=106) was stratified to include only football and men's basketball players who were of junior or senior status and had been enrolled at that institution for at least one year. The coach sample (n=29) included only football and men's basketball coaches. Three football and two basketball coaches (n=5) comprised each site sample. The administrative sample (n=25) included athletic directors and/or assistant or associate directors responsible for academic support and/or directors or coordinators of academic support programs. Administrators at each site (n=3) were selectively sampled. The faculty representative sample (n=8) included faculty who currently held the position of faculty athletic representative. Independent variables were organized into five categories: athletic department academic policies, practices, and interdepartmental relationships; athletic department relationships with academe; athletic-academic support services procedures, activities, and responsibilities; student-athlete preparation, development, involvement in campus life, and relationships with nonathlete peers; and coaches' actions, attitudes, and responsibilities. The findings of this study provided knowledge and understanding of how athletic department practices relate to the persistence and academic success of student-athletes. Recommendations included providing technology to students, creating freshmen interest groups across athletes, enhancing student-athlete development programming, and improving relationships with faculty on campus
Closed timelike curves in superfluid He
It is shown that the curved spacetime induced in a thin film of superfluid
He-A by the presence of symmetric vortices with the unbroken symmetry
phase, admits the existence of closed timelike curves through which only
superfluid clusters formed by anti-He atoms can travel and violate
causality.Comment: 7 pages, LaTex, to appear in Phys. Lett.
On the response of detectors in classical electromagnetic backgrounds
I study the response of a detector that is coupled non-linearly to a
quantized complex scalar field in different types of classical electromagnetic
backgrounds. Assuming that the quantum field is in the vacuum state, I show
that, when in {\it inertial} motion, the detector responds {\it only} when the
electromagnetic background produces particles. However, I find that the
response of the detector is {\it not} proportional to the number of particles
produced by the background.Comment: 10 pages, LaTeX, Final versio
A note on the analogy between superfluids and cosmology
A new analogy between superfluid systems and cosmology is here presented,
which relies strongly on the following ingredient: the back-reaction of the
vacuum to the quanta of sound waves. We show how the presence of thermal
phonons, the excitations above the quantum vacuum for , enable us to
deduce an hydrodynamical equation formally similar to the one obtained for a
perfect fluid in a Universe obeying the Friedmann-Robertson-Walker metric.Comment: Accepted for publication in Modern Physics Letters
Gravitational Thermodynamics of Space-time Foam in One-loop Approximation
We show from one-loop quantum gravity and statistical thermodynamics that the
thermodynamics of quantum foam in flat space-time and Schwarzschild space-time
is exactly the same as that of Hawking-Unruh radiation in thermal equilibrium.
This means we show unambiguously that Hawking-Unruh thermal radiation should
contain thermal gravitons or the contribution of quantum space-time foam. As a
by-product, we give also the quantum gravity correction in one-loop
approximation to the classical black hole thermodynamics.Comment: 7 pages, revte
Decoherence and entropy of primordial fluctuations II. The entropy budget
We calculate the entropy of adiabatic perturbations associated with a
truncation of the hierarchy of Green functions at the first non trivial level,
i.e. in a self-consistent Gaussian approximation. We give the equation
governing the entropy growth and discuss its phenomenology. It is parameterized
by two model-dependent kernels. We then examine two particular inflationary
models, one with isocurvature perturbations, the other with corrections due to
loops of matter fields. In the first model the entropy grows rapidely, while in
the second the state remains pure (at one loop).Comment: 28 page
Environmental Decoherence versus Intrinsic Decoherence
We review the difference between standard environmental decoherence and
'intrinsic decoherence', which is taken to be an ineluctable process of Nature.
Environmental decoherence is typically modeled by spin bath or oscillator modes
- we review some of the unanswered questions not captured by these models, and
also the application of them to experiments. Finally, a sketch is given of a
new theoretical approach to intrinsic decoherence, and this scheme is applied
to the discussion of gravitational decoherence.Comment: to be published in Phil Trans Roy Soc
Extensive Entropy Bounds
It is shown that, for systems in which the entropy is an extensive function
of the energy and volume, the Bekenstein and the holographic entropy bounds
predict new results. More explicitly, the Bekenstein entropy bound leads to the
entropy of thermal radiation (the Unruh-Wald bound) and the spherical entropy
bound implies the "causal entropy bound". Surprisingly, the first bound shows a
close relationship between black hole physics and the Stephan-Boltzmann law
(for the energy and entropy flux densities of the radiation emitted by a hot
blackbody). Furthermore, we find that the number of different species of
massless fields is bounded by .Comment: 8 pages, revtex, To appear in Phys. Rev.
Influence Functionals and the Accelerating Detector
The influence functional is derived for a massive scalar field in the ground
state, coupled to a uniformly accelerating DeWitt monopole detector in
dimensional Minkowski space. This confirms the local nature of the Unruh
effect, and provides an exact solution to the problem of the accelerating
detector without invoking a non-standard quantization. A directional detector
is presented which is efficiently decohered by the scalar field vacuum, and
which illustrates an important difference between the quantum mechanics of
inertial and non-inertial frames. From the results of these calculations, some
comments are made regarding the possibility of establishing a quantum
equivalence principle, so that the Hawking effect might be derived from the
Unruh effect.Comment: 32 page
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