More than “Just an Intern”: Undergraduate Internships in Academic Libraries

This presentation reports on the findings of a 2016 assessment of undergraduate internships at Musselman Library. The presentation will include the impact of these high-impact experiences on previous interns’ development of career goals, acceptance to and preparation for graduate education, and their early career

Compactness of the space of causal curves

We prove that the space of causal curves between compact subsets of a separable globally hyperbolic poset is itself compact in the Vietoris topology. Although this result implies the usual result in general relativity, its proof does not require the use of geometry or differentiable structure.Comment: 15 page

Suppressing Super-Horizon Curvature Perturbations?

We consider the possibility of suppressing superhorizon curvature perturbations after the end of the ordinary slow-roll inflationary stage. This is the opposite of the curvaton limit. We assume that large curvature perturbations are created by the inflaton and investigate if they can be diluted or suppressed by a second very homogeneous field which starts to dominate the energy density of the universe shortly after the end of inflation. We show explicit that the gravitational sourcing of inhomogeneities from the more inhomogeneous fluid to the more homogeneous fluid makes the suppression difficult if not impossible to achieve.Comment: 10 pages, 1 figure. Important revision. Conclusions more negativ

A three-node C deg element for analysis of laminated composite sandwich shells

A three-node flat shell element with C deg rotation fields has been developed for analysis of arbitrary composite shells. The element may consist of any number of orthotropic layers, each layer having different material properties and angular orientation. The formulation includes coupling between bending and extension, which is essential for analysis of unsymmetric laminates. Shearing deflections are included, since laminated and sandwich construction frequently results in shear stiffness much smaller than bending stiffness. Formulation of the element is straightforward, and calculation of its stiffness matrix is simple and fast. Convergence of solutions with mesh refinement is uniform for both thin and thick shells and is insensitive to element shape, although not as rapid as some other elements that lack one or more capabilities of the newly developed element. An experimental verification of the shall element is reported in the appendix

Interstellar HOCN in the Galactic center region

Aims. Our aim is to confirm the interstellar detection of cyanic acid, HOCN, in the Galactic center clouds. It has previously been tentatively detected only in Sgr B2(OH). Methods. We used a complete line survey of the hot cores Sgr B2(N) and (M) in the 3 mm range, complemented by additional observations carried out with the IRAM 30 m telescope at selected frequencies in the 2 mm band and towards four additional positions in the Sgr B2 cloud complex in the 2 and 3 mm bands. The spectral survey was analysed in the local thermodynamical equilibrium approximation (LTE) by modeling the emission of all identified molecules simultaneously. This allowed us to distinguish weak features of HOCN from the rich line spectrum observed in Sgr B2(N) and (M). Lines of the more stable (by 1.1 eV) isomer isocyanic acid, HNCO, in these sources, as well as those of HOCN and HNCO towards the other positions, were analysed in the LTE approximation as well. Results. Four transitions of HOCN were detected in a quiescent molecular cloud in the Galactic center at a position offset in (R.A., decl.) by (20'',100'') from the hot core source Sgr B2(M), confirming its previous tentative interstellar detection. Up to four transitions were detected toward five other positions in the Sgr B2 complex, including the hot cores Sgr B2(M), (S), and (N). A fairly constant abundance ratio of ~ 0.3 - 0.8 % for HOCN relative to HNCO was derived for the extended gas components, suggesting a common formation process of these isomers

Stau as the Lightest Supersymmetric Particle in R-Parity Violating SUSY Models: Discovery Potential with Early LHC Data

We investigate the discovery potential of the LHC experiments for R-parity violating supersymmetric models with a stau as the lightest supersymmetric particle (LSP) in the framework of minimal supergravity. We classify the final states according to their phenomenology for different R-parity violating decays of the LSP. We then develop event selection cuts for a specific benchmark scenario with promising signatures for the first beyond the Standard Model discoveries at the LHC. For the first time in this model, we perform a detailed signal over background analysis. We use fast detector simulations to estimate the discovery significance taking the most important Standard Model backgrounds into account. Assuming an integrated luminosity of 1 inverse femtobarn at a center-of-mass energy of 7 TeV, we perform scans in the parameter space around the benchmark scenario we consider. We then study the feasibility to estimate the mass of the stau-LSP. We briefly discuss difficulties, which arise in the identification of hadronic tau decays due to small tau momenta and large particle multiplicities in our scenarios.Comment: 26 pages, 18 figures, LaTeX; minor changes, final version published in PR

On the O II ground configuration energy levels

The most accurate way to measure the energy levels for the O II 2p^3 ground configuration has been from the forbidden lines in planetary nebulae. We present an analysis of modern planetary nebula data that nicely constrain the splitting within the ^2D term and the separation of this term from the ground ^4S_{3/2} level. We extend this method to H II regions using high-resolution spectroscopy of the Orion nebula, covering all six visible transitions within the ground configuration. These data confirm the splitting of the ^2D term while additionally constraining the splitting of the ^2P term. The energies of the ^2P and ^2D terms relative to the ground (^4S) term are constrained by requiring that all six lines give the same radial velocity, consistent with independent limits placed on the motion of the O+ gas and the planetary nebula data.Comment: 20 pages, 3 figures. To be published in Ap

Undergraduate Library Internships at Musselman Library, Gettysburg College

In 2015-2016, Musselman Library at Gettysburg College participated in Cohort 3 of the Association of College and Research Libraries’ Assessment in Action program. This report outlines an assessment completed of former undergraduate library interns in order to explore the impact their internship experience had on the development of career goals, acceptance to and preparation for graduate education, and their early career. Through an online survey (n= 45) and six semi-structured telephone interviews, respondents reported a positive impact on the above areas