Investigating the Consistency of Stellar Evolution Models with Globular Cluster Observations via the Red Giant Branch Bump

Synthetic RGBB magnitudes are generated with the most recent theoretical stellar evolution models computed with the Dartmouth Stellar Evolution Program (DSEP) code. They are compared to the observational work of Nataf et al., who present RGBB magnitudes for 72 globular clusters. A DSEP model using a chemical composition with enhanced $\alpha$ capture [$\alpha$/Fe] $=+0.4$ and an age of 13 Gyr shows agreement with observations over metallicities ranging from [Fe/H] = $0$ to [Fe/H] $\approx-1.5$, with discrepancy emerging at lower metallicities.Comment: 11 pages, 12 figure

Systematics and distributions of the genera Cyrtusa Erichson, Ecarinosphaerula Hatch, Isoplastus Horn, Liocyrtusa Daffner, Lionothus Brown, and Zeadolopus Broun of the United States and Canada (Coleoptera: Leiodidae: Leiodinae: Leiodini)

The following genera of Leiodini (Coleoptera: Leiodidae: Leiodinae) of the continental United States and Canada are reviewed: Cyrtusa Erichson, with two species; Isoplastus Horn, with two species (one new); Liocyrtusa Daffner, with three species; Lionothus Brown, with five species (three new), and Zeadolopus Broun, with four species (all genera are in the “Cyrtusa genus group”) and Ecarinosphaerula Hatch, with one named species (in the “Leiodes genus group”). The new species are Isoplastus floridanus Peck and Cook of Florida; Lionothus bidentatus Peck and Cook of Texas and Oklahoma, Lionothus exiguus Peck and Cook of Florida and Texas, and Lionothus parvoculus Peck and Cook of Arizona and New Mexico. Bionomic data on the species are given, and complete known distributions are mapped

A revision of the species of Anogdus LeConte of the United States and Canada (Coleoptera: Leiodidae: Leiodinae: Leiodini)

A review of the genus Anogdus LeConte (Coleoptera: Leiodidae: Leiodinae: Leiodini) of North America finds 16 species. Ten of these were previously described and there are no new synonyms. Six are named as new species: A. alachua n. sp., of Florida; A. cochise, n. sp., of Arizona; A. huachuca n. sp., of Arizona; A. rileyi n. sp, of Texas; A. texanus n. sp., of Texas and Oklahoma; and A. tridens n. sp, of Arkansas, Arizona, Illinois, Indiana, Oklahoma, and Texas. A key is provided to aid identification of the species

Cold uniform spherical collapse revisited

We report results of a study of the Newtonian dynamics of N self-gravitating particles which start in a quasi-uniform spherical configuration, without initial velocities. These initial conditions would lead to a density singularity at the origin at a finite time when N \rightarrow \infty, but this singularity is regulated at any finite N (by the associated density fluctuations). While previous studies have focussed on the behaviour as a function of N of the minimal size reached during the contracting phase, we examine in particular the size and energy of the virialized halo which results. We find the unexpected result that the structure decreases in size as N increases, scaling in proportion to N^{-1/3}, a behaviour which is associated with an ejection of kinetic energy during violent relaxation which grows in proportion to N^{1/3}. This latter scaling may be qualitatively understood, and if it represents the asymptotic behaviour in N implies that this ejected energy is unbounded above. We discuss also tests we have performed which indicate that this ejection is a mean-field phenomenon (i.e. a result of collisionless dynamics).Comment: 10 pages, 9 figures; proceedings of "Invisible Universe" conference, Paris, July 200

Beetle fauna of the island of Tobago, Trinidad and Tobago, West Indies

Tobago is a biologically rich but poorly investigated island. In this paper we report the occurrence of 672 species of beetles representing 69 families. Of these, only 95 had been previously reported from the island

Does text structure/summarization instruction facilitate learning from expository text?

The work upon which this publication is based was performed pursuant to Contract no. NIE-400-81-0030 of the National Institute of Educatio

Force distribution in a randomly perturbed lattice of identical particles with 1/r21/r^2 pair interaction

We study the statistics of the force felt by a particle in the class of spatially correlated distribution of identical point-like particles, interacting via a $1/r^2$ pair force (i.e. gravitational or Coulomb), and obtained by randomly perturbing an infinite perfect lattice. In the first part we specify the conditions under which the force on a particle is a well defined stochastic quantity. We then study the small displacements approximation, giving both the limitations of its validity, and, when it is valid, an expression for the force variance. In the second part of the paper we extend to this class of particle distributions the method introduced by Chandrasekhar to study the force probability density function in the homogeneous Poisson particle distribution. In this way we can derive an approximate expression for the probability distribution of the force over the full range of perturbations of the lattice, i.e., from very small (compared to the lattice spacing) to very large where the Poisson limit is recovered. We show in particular the qualitative change in the large-force tail of the force distribution between these two limits. Excellent accuracy of our analytic results is found on detailed comparison with results from numerical simulations. These results provide basic statistical information about the fluctuations of the interactions (i) of the masses in self-gravitating systems like those encountered in the context of cosmological N-body simulations, and (ii) of the charges in the ordered phase of the One Component Plasma.Comment: 23 pages, 10 figure