Higher education association lobbying: grassroots outreach as a signal of constituent opinion

This study sought to gain a better understanding of lobbying by the major DC-based higher education associations. To understand this phenomenon, this study looked at the lobbying tactics used by the associations and how they decide on what lobbying tactics to use. A qualitative, multiple case study approach was used with a sample comprised of association representatives and Congressional staffers. Overall, associations used a variety of tactics, but the for-profit association used more tactics and used all tactics more intensely compared to the non- profit associations. Particular focus was given to the tactic of membership mobilization using a signaling theory framework. Signaling theory explained why membership mobilization is an effective tactic because it signals to legislators that constituents care about an issue and could cause re-election consequences

COMPTEL observations of the quasar PKS 0528+134 during the first 3.5 years of the CGRO mission

The COMPTEL observations of the blazar-type quasar PKS 0528+134 in the energy range 0.75 MeV to 30 MeV carried out between April 1991 and September 1994 have been analyzed. During the first two years PKS 0528+134 was most significantly detected at energies above 3 MeV. During the last year there is only evidence for the quasar at energies below 3 MeV indicating a spectral change. The time-averaged COMPTEL energy spectrum between 0.75 MeV and 30 MeV is well represented by a power-law shape. Spectra collected from different observational periods reveal different power-law shapes: a hard state during flaring observations reported by EGRET, and a soft state otherwise. The combined simultaneous EGRET and COMPTEL spectra indicate these two spectral states as well. During low intensisty gamma-ray phases no spectral break is obvious from the combined COMPTEL and EGRET measurements. For the gamma-ray flaring phases however, the combined COMPTEL and EGRET data require a spectral bending at MeV-energies. By fitting broken power-law functions the best-fit values for the break in photon index range between 0.6 and 1.7, and for the break energy between ~5 MeV and ~20 MeV. Because the flux values measured by COMPTEL below 3 MeV in both states are roughly equal, the observations would be consistent with an additional spectral component showing up during gamma-ray flaring phases of PKS 0528+134. Such a component could be introduced by e.g. a high-energy electron-positron population with a low-energy cutoff in their bulk Lorentz factor distribution. The multiwavelength spectrum of PKS 0528+134 for gamma-ray flaring phases shows that the major energy release across the entire electro-magnetic spectrum is measured at MeV-energies.Comment: 10 pages, 8 postscript figures, latex, to appear in: A&A 328, 33 (1997

Simulations of Early Baryonic Structure Formation with Stream Velocity: I. Halo Abundance

It has been recently shown that the relative velocity between the dark matter and the baryons (vbc) at the time of recombination can affect the structure formation in the early universe (Tseliakhovich & Hirata 2010). We statistically quantify this effect using large cosmological simulations. We use three different high resolution sets of simulations (with separate transfer functions for baryons and dark matter) that vary in box size, particle number, and the value of the relative velocity between dark matter and baryons. We show that the total number density of halos is suppressed by ~ 20% at z = 25 for vbc = 1{\sigma}(vbc), where {\sigma}(vbc) is the variance of the relative velocity, while for vbc = 3.4{\sigma}(vbc) the relative suppression at the same redshift reaches 50%, remaining at or above the 30% level all the way to z = 11. We also find high abundance of "empty halos", i.e., halos that have gas fraction below half of the cosmic mean baryonic fraction fb. Specifically we find that for vbc = 1{\sigma}(vbc) all halos below 10^5M\odot are empty at z \geq 19. The high abundance of empty halos results in significant delay in the formation of gas rich mini-halos and the first galaxies.Comment: 7 pages, 8 figures, accepted to Ap

COMPTEL Observations of AGN at MeV-Energies

The COMPTEL experiment aboard CGRO, exploring the previously unknown sky at MeV-energies, has so far detected 10 Active Galactic Nuclei (AGN): 9 blazars and the radio galaxy Centaurus A. No Seyfert galaxy has been found yet. With these results COMPTEL has opened the field of extragalactic Gamma-ray astronomy in the MeV-band.Comment: 4 pages, 2 figures including 1 color plot, to appear in the Proceedings of the 3rd INTEGRAL Workshop "The Extreme Universe", held in Taormina, Italy, 14-18 September 199

Structure and Metal Binding Properties of ZnuA, a Periplasmic Zinc Transporter from \u3cem\u3eEscherichia coli\u3c/em\u3e

ZnuA is the periplasmic Zn2+-binding protein associated with the high-affinity ATP-binding cassette ZnuABC transporter from Escherichia coli. Although several structures of ZnuA and its homologs have been determined, details regarding metal ion stoichiometry, affinity, and specificity as well as the mechanism of metal uptake and transfer remain unclear. The crystal structures of E. coli ZnuA (Eco-ZnuA) in the apo, Zn2+-bound, and Co2+-bound forms have been determined. ZnZnuA binds at least two metal ions. The first, observed previously in other structures, is coordinated tetrahedrally by Glu59, His60, His143, and His207. Replacement of Zn2+ with Co2+ results in almost identical coordination geometry at this site. The second metal binding site involves His224 and several yet to be identified residues from the His-rich loop that is unique to Zn2+ periplasmic metal binding receptors. Electron paramagnetic resonance and X-ray absorption spectroscopic data on CoZnuA provide additional insight into possible residues involved in this second site. The second site is also detected by metal analysis and circular dichroism (CD) titrations. Eco-ZnuA binds Zn2+ (estimated K d \u3c 20 nM), Co2+, Ni2+, Cu2+, Cu+, and Cd2+, but not Mn2+. Finally, conformational changes upon metal binding observed in the crystal structures together with fluorescence and CD data indicate that only Zn2+ substantially stabilizes ZnuA and might facilitate recognition of ZnuB and subsequent metal transfer

Inclusive education technologies: emerging opportunities for people with visual impairments

Technology has become central to many activities of learning, ranging from its use in classroom education to work training, mastering a new hobby, or acquiring new skills of living. While digitally-enhanced learning tools can provide valuable access to information and personalised support, people with specific accessibility needs, such as low or no vision, can often be excluded from their use. This requires technology developers to build more inclusive designs and to offer learning experiences that can be shared by people with mixed-visual abilities. There is also scope to integrate DIY approaches and provide specialised teachers with the ability to design their own low cost educational tools, adapted to pedagogical objectives and to the variety of visual and cognitive abilities of their students. For researchers, this invites new challenges of how to best support technology adoption and its evaluation in often complex educational settings. This workshop seeks to bring together researchers and practitioners interested in accessibility and education to share best practices and lessons learnt for technology in this space; and to jointly discuss and develop future directions for the next generation design of inclusive and effective education technologies

Comptel observations of the quasar PKS 0528+134

During Phase I and Phase II of the CGRO‐mission, the quasar PKS 0528+134 was in the field of view of the COMPTEL instrument during several viewing periods. The quasar was detected by COMPTEL mainly at energies above 10 MeV. Below 10 MeV there is evidence for the source during some CGRO viewing periods, while below 3 MeV no signal is detected. The detections and non‐detections during different viewing periods follow the trend seen by EGRET, thereby indicating a time‐variable MEV‐flux of the quasar. The COMPTEL spectral results together with the simultaneously measured EGRET spectrum, indicate a spectral break in the upper part of the COMPTEL energy range at energies between 10 MeV and 30 MeV

Search for gamma‐ray emission from AGN with COMPTEL

The COMPTEL data (∼0.7–30 MeV) were searched for emission from AGN. Four sources have been detected so far: the quasars 3C 273, 3C 279, PKS 0528+134, and the radio galaxy Centaurus A. 3C 273 and 3C 279 were detected in CGRO observation period 3 with quite different spectral shapes. There is also evidence for 3C 273 at a weak flux level in observation period 11. The quasar PKS 0528+134 was detected above 3 MeV as part of a search for AGN already observed by EGRET. Cen A was seen up to 3 MeV by combining data from different observation periods

COMPTEL observations of the inner galaxy

This paper presents a first global study of COMPTEL observations of the inner Galaxy in the energy range 0.75–10 MeV. Preliminary findings demonstrate COMPTEL’s capabilities for mapping the observed gamma radiation and disentangling the contributions from point sources and diffuse emission