Community-Based Exercise Education During Colder Months

Approximately 50% of US adults and 75% of US high school students don\u27t meet recommended weekly physical activity guidelines, and physical activity declines further during colder seasons. Resources describing local suggestions for physical activity should be made broadly available to community members, such as at their primary health care office.https://scholarworks.uvm.edu/fmclerk/1514/thumbnail.jp

Numerical Models of Spin-Orbital Coupling in Neutron Star Binaries

We present a new numerical scheme for solving the initial value problem for quasiequilibrium binary neutron stars allowing for arbitrary spins. We construct sequences of circular-orbit binaries of varying separation, keeping the rest mass and circulation constant along each sequence. The spin angular frequency of the stars is shown to vary along the sequence, a result that can be derived analytically in the PPN limit. This spin effect, in addition to leaving an imprint on the gravitational waveform emitted during binary inspiral, is measurable in the electromagnetic signal if one of the stars is a pulsar visible from Earth.Comment: 4 pages, 3 figures. Submitted to the Proceedings of the "X Marcel Grossmann Meeting on General Relativity" in Rio de Janeiro, Brazil, July 20-26 (2003

Impact of Rotation on Quark-Hadron Hybrid Stars

Many recent observations give restrictions to the equation of state (EOS) for high-density matter. Theoretical studies are needed to try to elucidate these EOSs at high density and/or temperature. With the many known rapidly rotating neutron stars, e.g., pulsars, several theoretical studies have tried to take into account the effects of rotation. In our study of these systems, we find that one of our EOSs is consistent with recent observation, whereas the other is inconsistent.Comment: Quarks and Compact Stars 201

What Do We Really Know About Cosmic Acceleration?

Essentially all of our knowledge of the acceleration history of the Universe - including the acceleration itself - is predicated upon the validity of general relativity. Without recourse to this assumption, we use SNeIa to analyze the expansion history and find (i) very strong (5 sigma) evidence for a period of acceleration, (ii) strong evidence that the acceleration has not been constant, (iii) evidence for an earlier period of deceleration and (iv) only weak evidence that the Universe has not been decelerating since z~0.3.Comment: 9 pages, 8 figure

Critical Temperature for α\alpha-Particle Condensation within a Momentum Projected Mean Field Approach

Alpha-particle (quartet) condensation in homogeneous spin-isospin symmetric nuclear matter is investigated. The usual Thouless criterion for the critical temperature is extended to the quartet case. The in-medium four-body problem is strongly simplified by the use of a momentum projected mean field ansatz for the quartet. The self-consistent single particle wave functions are shown and discussed for various values of the density at the critical temperature

Maximal and inextensible polynomials and the geometry of the spectra of normal operators

We consider the set S(n,0) of monic complex polynomials of degree $n\ge 2$ having all their zeros in the closed unit disk and vanishing at 0. For $p\in S(n,0)$ we let $|p|_{0}$ denote the distance from the origin to the zero set of $p'$. We determine all 0-maximal polynomials of degree $n$, that is, all polynomials $p\in S(n,0)$ such that $|p|_{0}\ge |q|_{0}$ for any $q\in S(n,0)$. Using a second order variational method we then show that although some of these polynomials are inextensible, they are not necessarily locally maximal for Sendov's conjecture. This invalidates the recently claimed proofs of the conjectures of Sendov and Smale and shows that the method used in these proofs can only lead to (already known) partial results. In the second part of the paper we obtain a characterization of the critical points of a complex polynomial by means of multivariate majorization relations. We also propose an operator theoretical approach to Sendov's conjecture, which we formulate in terms of the spectral variation of a normal operator and its compression to the orthogonal complement of a trace vector. Using a theorem of Gauss-Lucas type for normal operators, we relate the problem of locating the critical points of complex polynomials to the more general problem of describing the relationships between the spectra of normal matrices and the spectra of their principal submatrices.Comment: A condensed version of the first half of this paper appeared in Math. Scand., see arXiv:math/0601600. Parts of the second half appeared in Trans. Amer. Math. Soc., see arXiv:math/0601519. The current version contains the full details of the counterexample constructions and some other result