External Shear in Quadruply Imaged Lens Systems

We use publicly available N-body simulations and semi-analytic models of galaxy formation to estimate the levels of external shear due to structure near the lens in gravitational lens systems. We also describe two selection effects, specific to four-image systems, that enhance the probability of observing systems to have higher external shear. Ignoring additional contributions from "cosmic shear" and assuming that lens galaxies are not significantly flattened, we find that the mean shear at the position of a quadruple lens galaxy is 0.11, the rms shear is roughly 0.15, and there is roughly a 45% likelihood of external shear greater than 0.1. This is much larger than previous estimates and in good agreement with typical measured external shear. The higher shear primarily stems from the tendency of early-type galaxies, which are the majority of lenses, to reside in overdense regions.Comment: 5 pages, 2 figures, ApJ in press, minor revision

Pharmaceuticals, Political Money, and Public Policy: A Theoretical and Empirical Agenda

Congress has consistently failed to solve some serious problems with the cost, effectiveness, and safety of pharmaceuticals. In part, this failure results from the pharmaceutical industry convincing legislators to define policy problems in ways that protect industry profits. By targeting campaign contributions to influential legislators and by providing them with selective information, the industry manages to displace the public’s voice in developing pharmaceutical policy

The Spitzer Gould Belt Survey of Large Nearby Interstellar Clouds: Discovery of A Dense Embedded Cluster in the Serpens-Aquila Rift

We report the discovery of a nearby, embedded cluster of young stellar objects, associated filamentary infrared dark cloud, and 4.5 mu m shock emission knots from outflows detected in Spitzer IRAC mid-infrared imaging of the Serpens-Aquila Rift obtained as part of the Spitzer Gould Belt Legacy Survey. We also present radial velocity measurements of the region from molecular line observations obtained with the Submillimeter Array (SMA) that suggest the cluster is comoving with the Serpens Main embedded cluster to the north. We therefore assign it 3 degrees the same distance, 260 pc. The core of the new cluster, which we call Serpens South, is composed of an unusually large fraction of protostars (77%) at high mean surface density (> 430 pc(-2)) and short median nearest neighbor spacing (3700 AU). We perform basic cluster structure characterization using nearest neighbor surface density mapping of the YSOs and compare our findings to other known clusters with equivalent analyses available in the literature.Astronom

Prospects for Campaign Finance Reform: The Role of Policy Narratives, Cultural Predispositions, and Political Knowledge in Collective Policy Preference Formation

Objective: Although campaign finance is a growing concern, pollsters rarely ask the public about reform. We use the variation in public support for campaign finance reform to determine factors important to collective policy preference formation. Methods: Using a national survey, we factor analyze the latent dimensions of various reforms, and rely on an experimental design to explain the role cultural theory, policy narratives, and political knowledge plays in preference formation. Results: The reform debate groups along two dimensions: adding or removing limitations, or ending the dependence on money altogether. We show policy narratives are most influential, and cultural theory has more explanatory value, among those with higher levels of political knowledge, and policy narratives tend to increase support among those who already support reform, and mitigate the opposition from other cultural types. Conclusion: If it were up to the public, prospects for campaign finance reform, even public financing, would be high

Organized Interests in Congressional Elections

Why do political action committees (PACs) donate money to some candidates and not others? Answers to this PAC-strategy question take two different forms. First, scholars emphasize demand-side variables of the legislative market (e.g., geographic location of PAC donors), culminating in the organizational presence model of PAC strategy, which discounts legislative strategies and finds that PACs donate to ideologically friendly, electorally vulnerable candidates who campaign where PACs have an organizational presence. Second, public choice scholars emphasize supply-side variables of the legislative market (e.g., congressional member attributes), culminating in the legislative asset model of PAC strategy, finding that PACs donate to the lowest cost congressional members in the best position to provide legislation, or a legislative strategy. Using data from the Center for Responsive Politics, I test each model using every PAC donation to a congressional candidate from 1990-2006, organized by the geographic location of PAC donor-bases and the PAC's policy sector. I find both models deficient in explaining PAC strategy. Only a small portion of PACs make decisions bounded by the geography of individual donors, making most PACs the nationalizing force many feared in the early 1980s. While PACs exhibit a clear strategy that seeks legislative benefit, the statistical significance of the legislative asset model comes from its ability to explain small donations with more accuracy than large PAC donations. In an attempt to reconcile these two approaches, I re-specify the legislative asset model with a conditional hypothesis: PACs donate money according to legislator characteristics and legislative strategies, but predominantly within the geography of its donor-base. This conditional hypothesis forms the foundation of a new mediated model, as the legislative strategy of PACs is mediated by the geographical distribution of its donor-base. This conditional hypothesis improves the explanatory power of PAC-strategy models marginally; however, the representational flaw in the PAC system still remains: PAC money creates financial constituencies that deviate from the geographic constituencies, exacerbating the differences between organized and unorganized interests in American political life

Cluster Lenses

Clusters of galaxies are the most recently assembled, massive, bound structures in the Universe. As predicted by General Relativity, given their masses, clusters strongly deform space-time in their vicinity. Clusters act as some of the most powerful gravitational lenses in the Universe. Light rays traversing through clusters from distant sources are hence deflected, and the resulting images of these distant objects therefore appear distorted and magnified. Lensing by clusters occurs in two regimes, each with unique observational signatures. The strong lensing regime is characterized by effects readily seen by eye, namely, the production of giant arcs, multiple-images, and arclets. The weak lensing regime is characterized by small deformations in the shapes of background galaxies only detectable statistically. Cluster lenses have been exploited successfully to address several important current questions in cosmology: (i) the study of the lens(es) - understanding cluster mass distributions and issues pertaining to cluster formation and evolution, as well as constraining the nature of dark matter; (ii) the study of the lensed objects - probing the properties of the background lensed galaxy population - which is statistically at higher redshifts and of lower intrinsic luminosity thus enabling the probing of galaxy formation at the earliest times right up to the Dark Ages; and (iii) the study of the geometry of the Universe - as the strength of lensing depends on the ratios of angular diameter distances between the lens, source and observer, lens deflections are sensitive to the value of cosmological parameters and offer a powerful geometric tool to probe Dark Energy. In this review, we present the basics of cluster lensing and provide a current status report of the field.Comment: About 120 pages - Published in Open Access at: http://www.springerlink.com/content/j183018170485723/ . arXiv admin note: text overlap with arXiv:astro-ph/0504478 and arXiv:1003.3674 by other author

Birds of the Northcentral Alaska Peninsula, 1976-1980

Between spring 1976 and fall 1980 we studied the occurrence, abundance, and habitat use of birds over a 2000 square km segment of the northcentral Alaska Peninsula. During this period observers were present 473 days and obtained records for all seasons. A total of 125 species was recorded; 63% (79 of 125) were water-associated. The breeding avifauna was found to be a mixture of Panboreal (49%), North American (34%), and Aleutican (17%) species. The Aleutican group was dominant in terms of biomass and numbers of individuals during the nonbreeding period. Forty-two species were confirmed breeding in the area and another 19 were suspected of breeding. The majority of birds occurred as migrants; 14 species were considered permanent residents and an additional 20 were winter residents. ... The area is a principal late summer and fall molting and staging area for several species of arctic and subarctic nesting waders and seaducks and emperor geese .... From late September through mid-October the density of water birds over the entire littoral and nearshore area approached 1000 birds square km. This density was exceeded many fold for certain species on particular segments of habitats in the area.Key words: birds, Alaska Peninsula, abundance, migration, nesting, habitat, distribution, zoogeographyMots clés: oiseaux, péninsule d'Alaska, abondance, migration, saison des nids, habitat, distribution, zoogéographi

The Seventh Data Release of the Sloan Digital Sky Survey

This paper describes the Seventh Data Release of the Sloan Digital Sky Survey (SDSS), marking the completion of the original goals of the SDSS and the end of the phase known as SDSS-II. It includes 11663 deg^2 of imaging data, with most of the roughly 2000 deg^2 increment over the previous data release lying in regions of low Galactic latitude. The catalog contains five-band photometry for 357 million distinct objects. The survey also includes repeat photometry over 250 deg^2 along the Celestial Equator in the Southern Galactic Cap. A coaddition of these data goes roughly two magnitudes fainter than the main survey. The spectroscopy is now complete over a contiguous area of 7500 deg^2 in the Northern Galactic Cap, closing the gap that was present in previous data releases. There are over 1.6 million spectra in total, including 930,000 galaxies, 120,000 quasars, and 460,000 stars. The data release includes improved stellar photometry at low Galactic latitude. The astrometry has all been recalibrated with the second version of the USNO CCD Astrograph Catalog (UCAC-2), reducing the rms statistical errors at the bright end to 45 milli-arcseconds per coordinate. A systematic error in bright galaxy photometr is less severe than previously reported for the majority of galaxies. Finally, we describe a series of improvements to the spectroscopic reductions, including better flat-fielding and improved wavelength calibration at the blue end, better processing of objects with extremely strong narrow emission lines, and an improved determination of stellar metallicities. (Abridged)Comment: 20 pages, 10 embedded figures. Accepted to ApJS after minor correction

Molecular epidemiological analysis of Escherichia coli sequence type ST131 (O25:H4) and bla CTX-M-15among extended-spectrum-β- lactamase-producing E. coli from the United States, 2000 to 2009

Escherichia coli sequence type ST131 (from phylogenetic group B2), often carrying the extended-spectrum-β-lactamase (ESBL) gene bla , is an emerging globally disseminated pathogen that has received comparatively little attention in the United States. Accordingly, a convenience sample of 351 ESBL-producing E. coli isolates from 15 U.S. centers (collected in 2000 to 2009) underwent PCR-based phylotyping and detection of ST131 and bla . A total of 200 isolates, comprising 4 groups of 50 isolates each that were (i) bla negative non-ST131, (ii) bla positive non-ST131, (iii) bla negative ST131, or (iv) bla positive ST131, also underwent virulence genotyping, antimicrobial susceptibility testing, and pulsed-field gel electrophoresis (PFGE). Overall, 201 (57%) isolates exhibited bla , whereas 165 (47%) were ST131. ST131 accounted for 56% of bla -positive-versus 35% of bla -negative isolates (