Exact treatment of ℓ≠0\ell \neq 0 states

Using the basic ingredient of supersymmetry, a general procedure for the treatment of quantum states having nonzero angular momenta is presented.Comment: 7 pages article in LaTEX (uses standard article.sty). No Figures. Accepted by Chinese Physics Letters (2004, vol 21. No.9

Extracting New Physics from the CMB

We review how initial state effects generically yield an oscillatory component in the primordial power spectrum of inflationary density perturbations. These oscillatory corrections parametrize unknown new physics at a scale $M$ and are potentially observable if the ratio $H_{infl}/M$ is sufficiently large. We clarify to what extent present and future CMB data analysis can distinguish between the different proposals for initial state corrections.Comment: Invited talk by B. Greene at the XXII Texas Symposium on Relativistic Astrophysics, Stanford University, 13-17 December 2004, (TSRA04-0001), 8 pages, LaTeX, some references added, added paragraph at the end of section 2 and an extra note added after the conclusions regarding modifications to the large k power spectra deduced from galaxy survey

c-Axis longitudinal magnetoresistance of the electron-doped superconductor Pr1.85Ce0.15CuO4

We report c-axis resistivity and longitudinal magnetoresistance measurements of superconducting Pr1.85Ce0.15CuO4 single crystals. In the temperature range 13K<T<32K, a negative magnetoresistance is observed at fields just above Hc2. Our studies suggest that this negative magnetoresistance is caused by superconducting fluctuations. At lower temperatures (T<13K), a different magnetoresistance behavior and a resistivity upturn are observed, whose origin is still unknown.Comment: Accepted for publication in Phys. Rev.

On the Theory of Fermionic Preheating

In inflationary cosmology, the particles constituting the Universe are created after inflation due to their interaction with moving inflaton field(s) in the process of preheating. In the fermionic sector, the leading channel is out-of equilibrium particle production in the non-perturbative regime of parametric excitation, which respects Pauli blocking but differs significantly from the perturbative expectation. We develop theory of fermionic preheating coupling to the inflaton, without and with expansion of the universe, for light and massive fermions, to calculate analytically the occupation number of created fermions, focusing on their spectra and time evolution. In the case of large resonant parameter $q$ we extend for rermions the method of successive parabolic scattering, earlier developed for bosonic preheating. In an expanding universe parametric excitation of fermions is stochastic. Created fermions very quickly, within tens of inflaton oscillations, fill up a sphere of radius $\simeq q^{1/4}$ in monetum space. We extend our formalism to the production of superheavy fermions and to `instant' fermion creation.Comment: 14 pages, latex, 12 figures, submitted for publicatio

Cryo-Jet Preservation of Calcium in the Rat Spinal Cord

In order to determine the distribution of diffusible ions, especially calcium, in rat spinal cord axons before and after trauma, sham, 6 hours post 6 gm/cm and 20 gm/cm trauma cords were cryo-jet frozen in situ and cryo-sections were subjected to electron probe X-ray microanalysis. The results confirm part of the Ca hypothesis, i.e., some spinal cord axons accumulate intracellular Ca after traumatic injury. In addition, 6 hours after trauma, Ca is only accumulated by axons that have also lost homeostasis. Thus, it is likely that observations of the continual rise of Ca in the traumatized spinal cord are due to an increase in the number of axons that have lost homeostasis rather than an overall increase in Ca within surviving cells

Bose-Einstein condensate of kicked rotators with time-dependent interaction

A modification of the quantum kicked rotator is suggested with a time-dependent delta-kicked interaction parameter which can be realized by a pulsed turn-on of a Feshbach resonance. The mean kinetic energy increases exponentially with time in contrast to a merely diffusive or linear growth for the first few kicks for the quantum kicked rotator with a constant interaction parameter. A recursive relation is derived in a self-consistent random phase approximation which describes this superdiffusive growth of the kinetic energy and is compared with numerical simulations. Unlike in the case of the quantum rotator with constant interaction, a Lax pair is not found. In general the delta-kicked interaction is found to lead to strong chaotic behaviour.Comment: 4 pages, 3 figure

Acceleration of the Universe driven by the Casimir force

We investigate an evolutional scenario of the FRW universe with the Casimir energy scaling like $(-)(1+z)^4$. The Casimir effect is used to explain the vacuum energy differences (its value measured from astrophysics is so small compared to value obtained from quantum field theory calculations). The dynamics of the FRW model is represented in terms of a two-dimensional dynamical system to show all evolutional paths of this model in the phase space for all admissible initial conditions. We find also an exact solution for non flat evolutional paths of Universe driven by the Casimir effect. The main difference between the FRW model with the Casimir force and the $\Lambda$CDM model is that their generic solutions are a set of evolutional paths with a bounce solution and an initial singularity, respectively. The evolutional scenario are tested by using the SNIa data, FRIIb radiogalaxies, baryon oscillation peak and CMB observation. We compare the power of explanation of the model considered and the $\Lambda$CDM model using the Bayesian information criterion and Bayesian factor. Our investigation of the information criteria of model selection showed the preference of the $\Lambda$CDM model over the model considered. However the presence of negative like the radiation term can remove a tension between the theoretical and observed primordial ${}^4$He and D abundance.Comment: RevTeX4, 17 pages, 9 figure

Combined Effect of Body Mass Index and Aerobic Fitness on Stress Fracture Risk among Women

Please view abstract in the attached PDF fil

The Effects of Dissolved Methane upon Liquid Argon Scintillation Light

In this paper we report on measurements of the effects of dissolved methane upon argon scintillation light. We monitor the light yield from an alpha source held 20 cm from a cryogenic photomultiplier tube (PMT) assembly as methane is injected into a high-purity liquid argon volume. We observe significant suppression of the scintillation light yield by dissolved methane at the 10 part per billion (ppb) level. By examining the late scintillation light time constant, we determine that this loss is caused by an absorption process and also see some evidence of methane-induced scintillation quenching at higher concentrations (50-100 ppb). Using a second PMT assembly we look for visible re-emission features from the dissolved methane which have been reported in gas-phase argon methane mixtures, and we find no evidence of visible re-emission from liquid-phase argon methane mixtures at concentrations between 10 ppb and 0.1%.Comment: 18 pages, 11 figures Updated to match published versio