The Halo Formation Rate and its link to the Global Star Formation Rate

The star formation history of the universe shows strong evolution with cosmological epoch. Although we know mergers between galaxies can cause luminous bursts of star formation, the relative importance of such mergers to the global star formation rate (SFR) is unknown. We present a simple analytic formula for the rate at which halos merge to form higher-mass systems, derived from Press-Schechter theory and confirmed by numerical simulations (for high halo masses). A comparison of the evolution in halo formation rate with the observed evolution in the global SFR indicates that the latter is largely driven by halo mergers at z>1. Recent numerical simulations by Kolatt et al. (1999) and Knebe & Muller (1999) show how merging systems are strongly biased tracers of mass fluctuations, thereby explaining the strong clustering observed for Lyman-break galaxies without any need to assume that Lyman-break galaxies are associated only with the most massive systems at z~3.Comment: 4 pages, 2 figures. To appear in `The Hy-redshift universe: Galaxy formation and evolution at high redshift' eds. A.J. Bunker and W.J.M. van Breuge

Fourth Amendment Accommodations: (UN)Compelling Public Needs, Balancing Acts, and the Fiction of Consent

The problems of public housing-including crime, drugs, and gun violence- have received an enormous amount of national attention. Much attention has also focused on warrantless searches and consent searches as solutions to these problems. This Note addresses the constitutionality of these proposals and asserts that if the Supreme Court\u27s current Fourth Amendment jurisprudence is taken to its logical extremes, warrantless searches in public housing can be found constitutional. The author argues, however, that such an interpretation fails to strike the proper balance between public need and privacy in the public housing context. The Note concludes by proposing alternative consent-based regimes that would pass constitutional muster

An EEG approach to aspects of insomnia

The research programme was initiated by a study of possible non-drug "aids" to insomnia. Using a group of self-reported, sleep-onset insomniacs, the efficacies of cycloid vibration, Horlicks and cocoa (placebo condition) were assessed by all-night EEG recordings. None of these "aids" were found to have significant effects upon either the quality or quantity of sleep. However, two interesting observations of this study were: (1) the unreliability of subjective reports of insomnia—the insomniacs, in general, tended to overestimate their sleep onset times; (2) the frequent use of Aspirin by the self-reported insomniacs to relieve their sleeping difficulties. These observations served as the bases for further investigation. [Continues.

Sweet Home; or, Friendship\u27s Golden Altar

This is a book of prose and poetry for women. According to the preface, the object of the book is to, ...awaken the memories of home--to remind us of the old scenes and old times, and kindle on old hearthstones the old fires. The contents of the book include prose by men, women, and anonymous submission. Titles in the prose section include: How she found the Time, by Mrs. Caroline A. Soule; Mother, Mother, by Henry Clay; and The Whole Family, by Mrs. Sedgwick. Titles in the poetry section include, My Angel Love, by Fanny Forrester; Brother, come Home, by Miss Waterman; and Maiden Beauty, by Charles Swain. The books within the Mother, Home, and Heaven Collection were given in honor of Josephine Long Wishart by her daughter Josephine Wishart Hayford, who graduated from The College of Wooster in 1937.https://openworks.wooster.edu/motherhomeheaven/1000/thumbnail.jp

Sweet Home; or, Friendship\u27s Golden Altar

Sweet Home; or, Friendship\u27s Golden Altar written by Frances E Percival is a poetry book. There are two sections: prose and poetry. There are many different authors of the poems and proses, a including work that is anonymous. All of the writings are about life at home. In the preface Percival writes, There is no place like home! There are approximately 30 prose pieces and 75 pieces in the poetry section.https://openworks.wooster.edu/motherhomeheaven/1024/thumbnail.jp

Using galaxy pairs as cosmological tracers

The Alcock-Paczynski (AP) effect uses the fact that, when analyzed with the correct geometry, we should observe structure that is statistically isotropic in the Universe. For structure undergoing cosmological expansion with the background, this constrains the product of the Hubble parameter and the angular diameter distance. However, the expansion of the Universe is inhomogeneous and local curvature depends on density. We argue that this distorts the AP effect on small scales. After analyzing the dynamics of galaxy pairs in the Millennium simulation, we find an interplay between peculiar velocities, galaxy properties and local density that affects how pairs trace cosmological expansion. We find that only low mass, isolated galaxy pairs trace the average expansion with a minimum "correction" for peculiar velocities. Other pairs require larger, more cosmology and redshift dependent peculiar velocity corrections and, in the small-separation limit of being bound in a collapsed system, do not carry cosmological information.Comment: 15 pages, 14 figures, 1 tabl

Clustering of Photometric Luminous Red Galaxies II: Cosmological Implications from the Baryon Acoustic Scale

A new determination of the sound horizon scale in angular coordinates is presented. It makes use of ~ 0.6 x 10^6 Luminous Red Galaxies, selected from the Sloan Digital Sky Survey imaging data, with photometric redshifts. The analysis covers a redshift interval that goes from z=0.5 to z=0.6. We find evidence of the Baryon Acoustic Oscillations (BAO) signal at the ~ 2.3 sigma confidence level, with a value of theta_{BAO} (z=0.55) = (3.90 \pm 0.38) degrees, including systematic errors. To our understanding, this is the first direct measurement of the angular BAO scale in the galaxy distribution, and it is in agreement with previous BAO measurements. We also show how radial determinations of the BAO scale can break the degeneracy in the measurement of cosmological parameters when they are combined with BAO angular measurements. The result is also in good agreement with the WMAP7 best-fit cosmology. We obtain a value of w_0 = -1.03 \pm 0.16 for the equation of state parameter of the dark energy, Omega_M = 0.26 \pm 0.04 for the matter density, when the other parameters are fixed. We have also tested the sensitivity of current BAO measurements to a time varying dark energy equation of state, finding w_a = 0.06 \pm 0.22 if we fix all the other parameters to the WMAP7 best-fit cosmology.Comment: 7 pages, 7 figures, Accepted for publication to MNRA

From Heisenberg matrix mechanics to EBK quantization: theory and first applications

Despite the seminal connection between classical multiply-periodic motion and Heisenberg matrix mechanics and the massive amount of work done on the associated problem of semiclassical (EBK) quantization of bound states, we show that there are, nevertheless, a number of previously unexploited aspects of this relationship that bear on the quantum-classical correspondence. In particular, we emphasize a quantum variational principle that implies the classical variational principle for invariant tori. We also expose the more indirect connection between commutation relations and quantization of action variables. With the help of several standard models with one or two degrees of freedom, we then illustrate how the methods of Heisenberg matrix mechanics described in this paper may be used to obtain quantum solutions with a modest increase in effort compared to semiclassical calculations. We also describe and apply a method for obtaining leading quantum corrections to EBK results. Finally, we suggest several new or modified applications of EBK quantization.Comment: 37 pages including 3 poscript figures, submitted to Phys. Rev.