Filling in the Gaps in the 4.85 GHz Sky

We describe a 4.85 GHz survey of bright, flat-spectrum radio sources conducted with the Effelsberg 100 m telescope in an attempt to improve the completeness of existing surveys, such as CRATES. We report the results of these observations and of follow-up 8.4 GHz observations with the VLA of a subset of the sample. We comment on the connection to the WMAP point source catalog and on the survey's effectiveness at supplementing the CRATES sky coverage.Comment: 13 pages, 3 figures, 2 tables. Accepted for publication in the Astronomical Journal. Tables available in electronic form: http://astro.stanford.edu/gaps

Optical Spectroscopy of Bright Fermi LAT Blazars

We report on HET and Palomar 5 m spectroscopy of recently identified $\gamma$-ray blazars in the {\it Fermi} LAT Bright Source List. These data provide identifications for 10 newly discovered $\gamma$-ray flat spectrum radio quasars (FSRQ) and six new BL Lacs plus improved spectroscopy for six additional BL Lacs. We substantially improve the identification completeness of the bright LAT blazars and give new redshifts and $z$ constraints, new estimates of the black hole masses and new measurements of the optical SED.Comment: 8 pages, 5 figures, 2 tables. Accepted for publication in Ap

An intelligent, free-flying robot

The ground based demonstration of the extensive extravehicular activity (EVA) Retriever, a voice-supervised, intelligent, free flying robot, is designed to evaluate the capability to retrieve objects (astronauts, equipment, and tools) which have accidentally separated from the Space Station. The major objective of the EVA Retriever Project is to design, develop, and evaluate an integrated robotic hardware and on-board software system which autonomously: (1) performs system activation and check-out; (2) searches for and acquires the target; (3) plans and executes a rendezvous while continuously tracking the target; (4) avoids stationary and moving obstacles; (5) reaches for and grapples the target; (6) returns to transfer the object; and (7) returns to base

Outbreak of acute hepatitis C following the use of anti-hepatitis C virus--screened intravenous immunoglobulin therapy

BACKGROUND and AIMS: Hepatitis C virus (HCV) infection has been associated with intravenous (IV) immunoglobulin (Ig), and plasma donations used to prepare IV Ig are now screened to prevent transmission. Thirty-six patients from the United Kingdom received infusions from a batch of anti-HCV antibody-screened intravenous Ig (Gammagard; Baxter Healthcare Ltd., Thetford, Norfolk, England) that was associated with reports of acute hepatitis C outbreak in Europe. The aim of this study was to document the epidemiology of this outbreak. METHODS: Forty-six patients from the United Kingdom treated with Gammagard (34 exposed and 12 unexposed to the batch) returned epidemiological questionnaires. RESULTS: Eighty-two percent of the exposed patients (28 of 34) became positive for HCV RNA. Eighteen percent of the patients (6 of 34) who had infusions with this batch tested negative for HCV RNA, but 2 of the patients had abnormal liver function and subsequently seroconverted to anti-HCV antibody positive. Twenty-seven percent of the patients (9 of 34) developed jaundice, and 79% (27 of 34) had abnormal liver transferase levels. Virus isolates (n=21), including an isolate from the implicated batch, were genotype 1a and virtually identical by sequence analysis of the NS5 region, consistent with transmission from a single source. CONCLUSIONS: Hepatitis C infection can be transmitted by anti-HCV-screened IV Ig. Careful documentation of IV Ig batch numbers and regular biochemical monitoring is recommended for all IV Ig recipients

CGRaBS: An All-Sky Survey of Gamma-Ray Blazar Candidates

We describe a uniform all-sky survey of bright blazars, selected primarily by their flat radio spectra, that is designed to provide a large catalog of likely gamma-ray AGN. The defined sample has 1625 targets with radio and X-ray properties similar to those of the EGRET blazars, spread uniformly across the |b| > 10 deg sky. We also report progress toward optical characterization of the sample; of objects with known R < 23, 85% have been classified and 81% have measured redshifts. One goal of this program is to focus attention on the most interesting (e.g., high redshift, high luminosity, ...) sources for intensive multiwavelength study during the observations by the Large Area Telescope (LAT) on GLAST.Comment: 18 pages, 6 figures, 1 machine-readable table available at http://astro.stanford.edu/CGRaBS/ ; accepted for publication in ApJ

J16021+3326: New Multi-Frequency Observations of a Complex Source

We present multifrequency Very Long Baseline Array (VLBA) observations of J16021+3326. These observations, along with variability data obtained from the Owens Valley Radio Observatory (OVRO) candidate gamma-ray blazar monitoring program, clearly indicate this source is a blazar. The peculiar characteristic of this blazar, which daunted previous classification attempts, is that we appear to be observing down a precessing jet, the mean orientation of which is aligned with us almost exactly.Comment: 16 pages, 7 Figures, 2 Tables, accepted to Ap

Characteristics of EGRET Blazars in the VLBA Imaging and Polarimetry Survey (VIPS)

We examine the radio properties of EGRET-detected blazars observed as part of the VLBA Imaging and Polarimetry Survey (VIPS). VIPS has a flux limit roughly an order of magnitude below the MOJAVE survey and most other samples that have been used to study the properties of EGRET blazars. At lower flux levels, radio flux density does not directly correlate with gamma-ray flux density. We do find that the EGRET-detected blazars tend to have higher brightness temperatures, greater core fractions, and possibly larger than average jet opening angles. A weak correlation is also found with jet length and with polarization. All of the well-established trends can be explained by systematically larger Doppler factors in the gamma-ray loud blazars, consistent with the measurements of higher apparent velocities found in monitoring programs carried out at radio frequencies above 10 GHz.Comment: 20 pages, 7 figures, accepted to Ap

Spectroscopy of Broad Line Blazars from 1LAC

We report on optical spectroscopy of 165 Flat Spectrum Radio Quasars (FSRQs) in the Fermi 1LAC sample, which have helped allow a nearly complete study of this population. Fermi FSRQ show significant evidence for non-thermal emission even in the optical; the degree depends on the gamma-ray hardness. They also have smaller virial estimates of hole mass than the optical quasar sample. This appears to be largely due to a preferred (axial) view of the gamma-ray FSRQ and non-isotropic (H/R ~ 0.4) distribution of broad-line velocities. Even after correction for this bias, the Fermi FSRQ show higher mean Eddington ratios than the optical population. A comparison of optical spectral properties with Owens Valley Radio Observatory radio flare activity shows no strong correlation.Comment: Accepted for publication in Ap

15 GHz Monitoring of Gamma-ray Blazars with the OVRO 40 Meter Telescope in Support of Fermi

We present results from the first two years of our fast-cadence 15 GHz gamma-ray blazar monitoring program, part of the F-GAMMA radio monitoring project. Our sample includes the 1158 blazars north of -20 degrees declination from the Candidate Gamma-Ray Blazar Survey (CGRaBS), which encompasses a significant fraction of the extragalactic sources detected by the Fermi Gamma-ray Space Telescope. We introduce a novel likelihood analysis for computing a time series variability amplitude statistic that separates intrinsic variability from measurement noise and produces a quantitative error estimate. We use this method to characterize our radio light curves. We also present results indicating a statistically significant correlation between simultaneous average 15 GHz radio flux density and gamma-ray photon flux.Comment: 5 pages, 7 figures; 2009 Fermi Symposium; eConf Proceedings C09112

An intelligent assistant for exploratory data analysis

In this paper we present an account of the main features of SNOUT, an intelligent assistant for exploratory data analysis (EDA) of social science survey data that incorporates a range of data mining techniques. EDA has much in common with existing data mining techniques: its main objective is to help an investigator reach an understanding of the important relationships ina data set rather than simply develop predictive models for selectd variables. Brief descriptions of a number of novel techniques developed for use in SNOUT are presented. These include heuristic variable level inference and classification, automatic category formation, the use of similarity trees to identify groups of related variables, interactive decision tree construction and model selection using a genetic algorithm