The total nucleon-nucleon cross section at large N_c

It is shown that at sufficiently large $N_c$ for incident momenta which are much larger than the QCD, the total nucleon-nucleon cross section is independent of incident momentum and given by $\sigma^{\rm total}=2 \pi \log^2(N_c) / (m^2_{\pi})$. This result is valid in the extreme large $N_c$ regime of $\log(N_c) \gg 1$ and has corrections of relative order $\log (\log(N_c))/\log(N_c)$. A possible connection of this result to the Froissart-Martin bound is discussed.Comment: 4 page

Constraints on galaxy formation from alpha-enhancement in luminous elliptical galaxies

We explore the formation of alpha-enhanced and metal-rich stellar populations in the nuclei of luminous ellipticals under the assumption of two extreme galaxy formation scenarios based on hierarchical clustering, namely a fast clumpy collapse and the merger of two spirals. We investigate the parameter space of star formation time-scale, IMF slope, and stellar yields. In particular, the latter add a huge uncertainty in constraining time-scales and IMF slopes. We find that -- for Thielemann, Nomoto & Hashimoto nucleosynthesis -- in a fast clumpy collapse scenario an [alpha/Fe] overabundance of approx. 0.2 dex in the high metallicity stars can be achieved with a Salpeter IMF and star formation time-scales of the order 10^9 yr. The scenario of two merging spirals which are similar to our Galaxy, instead, fails to reproduce alpha-enhanced abundance ratios in the metal-rich stars, unless the IMF is flattened during the burst ignited by the merger. This result is independent of the burst time-scale. We suggest that abundance gradients give hints to distinguish between the two extreme formation scenarios considered in this paper.Comment: Accepted for publication in MNRAS, LaTex 2.09 with mn.sty, 13 pages, 5 figure

A Methodology for Three-Dimensional Quantification of Anterior Tooth Width

The use of cone-beam computed tomography (CBCT) technology has been shown to be more accurate in measuring individual incisor tooth widths than the use of wax exemplars. There were fewer differences by investigators using CBCT than others using an F-test in a mixed model of the measurement differences of investigators, wax type, and which tooth was measured. In addition, the frequency of outliers was less in the CBCT method (a total of 5) as compared to the two-dimensional measurements in ether Aluwax (a total of 8) or Coprwax (a total of 12). Both results indicate that CBCT measurements accounted more precisely for tooth width and level of eruption

A heuristic approach to the weakly interacting Bose gas

Some thermodynamic properties of weakly interacting Bose systems are derived from dimensional and heuristic arguments and thermodynamic relations, without resorting to statistical mechanics

Perceived Equity, Motivation and Final Offer Arbitration in Major League Baseball

Final offer salary arbitration in major league baseball offers a unique institutional arrangement that creates a naturally occurring non-equivalent groups repeated measure research design. The structural arrangements allow for examination of anticipatory expectancy effects and for assessment of behavioral responses consistent with equity theory predictions. Additionally, equity theory can be tested without the methodological problems inherent in defining the referent other. Performance and mobility were examined for major league baseball position players who won and lost their arbitration hearings. Pre-arbitration performance was found to significantly predict arbitration outcome. Despite similar patterns of post-arbitration performance between winners and losers, a significant relationship was noted between losing arbitration and postarbitration performance declines. Analyses also suggested that losers were also significantly more likely to change teams and leave major league baseball. The causality of the relationship between performance and arbitration outcome is discussed along with expectancy and equity effects as they relate to performance and mobility following the arbitration intervention

“Inextricably Intertwined” Explicable at Last?: Rooker-Feldman Analysis After the Supreme Court’s Exxon Mobil Decision

The Supreme Court\u27s March 2005 decision in \u27Exxon Mobil Corp. v. Saudi Basic Industries Corp.\u27 substantially limited the Rooker-Feldman doctrine, under which lower federal courts largely lack jurisdiction to engage in what amounts to de facto review of state-court decisions. Exxon Mobil\u27s holding is quite narrow--entry of a final state-court judgment does not destroy federal-court jurisdiction already acquired over parallel litigation. But the Court\u27s articulation of when Rooker-Feldman applies, and its approach in deciding the case, have significant implications for several aspects of Rooker-Feldman jurisprudence. Chief among our claims is that although the Court did not expressly repudiate or limit the applicability of the inextricably intertwined formulation from prior cases, which had been a primary test for many lower courts, that concept appears to have been relegated to some secondary role and no longer to be a general or threshold test. The Exxon Mobil Court properly did not elaborate on just what the concept\u27s role should be, but we offer a suggestion based on an earlier Ninth Circuit decision. We also discuss the apparent impact of Exxon Mobil on other aspects of Rooker-Feldman doctrine as the lower federal courts had developed it, including relation to preclusion doctrines, the significance of whether the federal plaintiff was plaintiff or defendant in state court, and the doctrine\u27s applicability a) to those not parties to prior state-court litigation, b) to interlocutory state-court rulings and decisions of lower state courts, and c) when federal-court plaintiffs did not raise their federal claims in state court. A February 2006 per curiam decision applying Exxon Mobil, Lance v. Dennis, reinforces the Court\u27s position on some of these issues

Non-parametric Cosmology with Cosmic Shear

We present a method to measure the growth of structure and the background geometry of the Universe -- with no a priori assumption about the underlying cosmological model. Using Canada-France-Hawaii Lensing Survey (CFHTLenS) shear data we simultaneously reconstruct the lensing amplitude, the linear intrinsic alignment amplitude, the redshift evolving matter power spectrum, P(k,z), and the co-moving distance, r(z). We find that lensing predominately constrains a single global power spectrum amplitude and several co-moving distance bins. Our approach can localise precise scales and redshifts where Lambda-Cold Dark Matter (LCDM) fails -- if any. We find that below z = 0.4, the measured co-moving distance r (z) is higher than that expected from the Planck LCDM cosmology by ~1.5 sigma, while at higher redshifts, our reconstruction is fully consistent. To validate our reconstruction, we compare LCDM parameter constraints from the standard cosmic shear likelihood analysis to those found by fitting to the non-parametric information and we find good agreement.Comment: 13 pages. Matches PRD accepted versio

Computer vision for real-time orbital operations. Center directors discretionary fund

Machine vision research is examined as it relates to the NASA Space Station program and its associated Orbital Maneuvering Vehicle (OMV). Initial operation of OMV for orbital assembly, docking, and servicing are manually controlled from the ground by means of an on board TV camera. These orbital operations may be accomplished autonomously by machine vision techniques which use the TV camera as a sensing device. Classical machine vision techniques are described. An alternate method is developed and described which employs a syntactic pattern recognition scheme. It has the potential for substantial reduction of computing and data storage requirements in comparison to the Two-Dimensional Fast Fourier Transform (2D FFT) image analysis. The method embodies powerful heuristic pattern recognition capability by identifying image shapes such as elongation, symmetry, number of appendages, and the relative length of appendages