The MAGIC Telescope: Prospects for GRB research

The Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) Telescope collaboration is constructing a large Cherenkov telescope (17 m diameter) for the exploration of the gamma-ray energy regime above 10 GeV with high sensitivity. One of the highlights in the science program of this future observatory are the plans for fast follow-up observations of of GRBs. By ``fast'' we mean delays of less than 30 s between notification and the beginning of observations. The expected gamma counting rates are of the order of 100 Hz for a EGRET counting rate of 0.1 Hz above 100 MeV and a spectral index of 2.0 (this would correspond to a fluence of 10^{-5} erg cm^{-2} for 60 s burst duration). The good photon statistics will permit determination of spectra, search for cutoffs and measurement of light-curves with a time resolution of the order of 1 s

PC1643+4631A,B: The Lyman-Alpha Forest at the Edge of Coherence

This is the first measurement and detection of coherence in the intergalactic medium (IGM) at substantially high redshift (z~3.8) and on large physical scales (~2.5 h^-1 Mpc). We perform the measurement by presenting new observations from Keck LRIS of the high redshift quasar pair PC 1643+4631A, B and their Ly-alpha absorber coincidences. This experiment extends multiple sightline quasar absorber studies to higher redshift, higher opacity, larger transverse separation, and into a regime where coherence across the IGM becomes weak and difficult to detect. We fit 222 discrete Ly-alpha absorbers to sightline A and 211 to sightline B. Relative to a Monte Carlo pairing test (using symmetric, nearest neighbor matching) the data exhibit a 4sigma excess of pairs at low velocity splitting (<150 km/s), thus detecting coherence on transverse scales of ~2.5 h^-1 Mpc. We use spectra extracted from an SPH simulation to analyze symmetric pair matching, transmission distributions as a function of redshift and compute zero-lag cross-correlations to compare with the quasar pair data. The simulations agree with the data with the same strength (~4sigma) at similarly low velocity splitting above random chance pairings. In cross-correlation tests, the simulations agree when the mean flux (as a function of redshift) is assumed to follow the prescription given by Kirkman et al. (2005). While the detection of flux correlation (measured through coincident absorbers and cross-correlation amplitude) is only marginally significant, the agreement between data and simulations is encouraging for future work in which even better quality data will provide the best insight into the overarching structure of the IGM and its understanding as shown by SPH simulations.Comment: 15 pages, 11 figures; accepted for publication in Astronomical Journa

Instructional Technology Usage and Implications for Student Academic Achievement and Further Success

The digital divide was once a term used to indicate disparity between socio-economic classes and access to digital devices. The digital divide may now more accurately indicate differences in the types of usage between members of different socio-economic classes. Differences in usage among the middle school student population may play a role in the development of critical thinking and collaborative communication. The Maryland results of the 2010 Speak Up survey – a national student survey regarding the usage of technology - were used in comparison with student respondent school district differentiation and were also compared with student state standardized test scores. No statistically significant relationships were found between student responses to questions of technology access or usage, dependent on urban or suburban/rural district setting

Potential Food and Nonfood Utilization of Potatoes and Related Byproducts in North Dakota

Demand and Price Analysis,

Probing Split Supersymmetry with Cosmic Rays

A striking aspect of the recently proposed split supersymmetry is the existence of heavy gluinos which are metastable because of the very heavy squarks which mediate their decay. In this paper we correlate the expected flux of these particles with the accompanying neutrino flux produced in inelastic $pp$ collisions in distant astrophysical sources. We show that an event rate at the Pierre Auger Observatory of approximately 1 yr$^{-1}$ for gluino masses of about 500 GeV is consistent with existing limits on neutrino fluxes. The extremely low inelasticity of the gluino-containing hadrons in their collisions with the air molecules makes possible a distinct characterization of the showers induced in the atmosphere. Should such anomalous events be observed, we show that their cosmogenic origin, in concert with the requirement that they reach the Earth before decay, leads to a lower bound on their proper lifetime of the order of 100 years, and consequently, to a lower bound on the scale of supersymmetry breaking, $\Lambda_{\rm SUSY} >2.6 \times 10^{11}$ GeV. Obtaining such a bound is not possible in collider experiments.Comment: Version to be published in Phys. Rev.

The Economics of Exporting North Dakota Beef to Asian Pacific Markets

International Relations/Trade,