Sensitive Radio Survey of Obscured Quasar Candidates

We study the radio properties of moderately obscured quasars over a range of redshifts to understand the role of radio activity in accretion using the Jansky Very Large Array (JVLA) at 6.0GHz and 1.4GHz. Our z~2.5 sample consists of optically-selected obscured quasar candidates, all of which are radio-quiet, with typical radio luminosities of $\nu L_{\nu}$[1.4 GHz] < $10^{40}$ erg s$^{-1}$. Only a single source is individually detected in our deep (rms~10 $\mu$Jy) exposures. This population would not be identified by radio-based selection methods used for distinguishing dusty star-forming galaxies and obscured active nuclei. In our pilot A-array study of z~0.5 radio-quiet quasars, we spatially resolve four of five objects on scales ~ 5 kpc and find they have steep spectral indices. Therefore, radio emission in these sources could be due to jet-driven or radiatively driven bubbles interacting with interstellar material on the scale of the host galaxy. Finally, we also study the population of ~ 200 faint (~40 $\mu$Jy - 40 mJy) radio sources observed over ~ 120 arcmin$^2$ of our data. 60% of these detections are matched in the SDSS and/or WISE and are, in roughly equal shares, active nuclei at a broad range of redshifts, passive galaxies with no other signs of nuclear activity and IR-bright but optically faint sources. Spectroscopically or photometrically confirmed star-forming galaxies constitute only a small minority of the matches. Such sensitive radio surveys allow us to address important questions of AGN evolution and evaluate the AGN contribution to the radio-quiet sky.Comment: 18 pages, submitted to MNRA

Terrain Sculptor: generalizing terrain models for relief shading

Shaded relief derived from high-resolution terrain models often contains distracting terrain details that need to be removed for medium- and small- scale mapping. When standard raster filter operations are applied to digital terrain data, important ridge tops and valley edges are blurred, altering the characteristic shape of these features in the resulting shaded relief. This paper introduces Terrain Sculptor, a software application that prepares generalized terrain models for relief shading. The application uses a generalization methodology based on a succession of raster operations. Curvature coefficients detect and accentuate important relief features. Terrain Sculptor offers a graphical user interface to adjust the algorithm to various scales and terrain resolutions

Composite Spectral Energy Distributions and Infrared-Optical Colors of Type 1 and Type 2 Quasars

We present observed mid-infrared and optical colors and composite spectral energy distributions (SEDs) of type 1 (broad-line) and 2 (narrow-line) quasars selected from Sloan Digital Sky Survey (SDSS) spectroscopy. A significant fraction of powerful quasars are obscured by dust, and are difficult to detect in optical photometric or spectroscopic surveys. However these may be more easily identified on the basis of mid-infrared (MIR) colors and SEDs. Using samples of SDSS type 1 type 2 matched in redshift and [OIII] luminosity, we produce composite rest-frame 0.2-15 micron SEDs based on SDSS, UKIDSS, and Wide-Field Infrared Survey Explorer (WISE) photometry and perform model fits using simple galaxy and quasar SED templates. The SEDs of type 1 and 2 quasars are remarkably similar, with the differences explained primarily by the extinction of the quasar component in the type 2 systems. For both types of quasar, the flux of the AGN relative to the host galaxy increases with AGN luminosity (L_[OIII]) and redder observed MIR color, but we find only weak dependencies of the composite SEDs on mechanical jet power as determined through radio luminosity. We conclude that luminous quasars can be effectively selected using simple MIR color criteria similar to those identified previously (W1-W2 > 0.7 [Vega]), although these criteria miss many heavily obscured objects. Obscured quasars can be further identified based on optical-IR colors (for example, (u-W3 [AB]) > 1.4(W1-W2 [Vega])+3.2). These results illustrate the power of large statistical studies of obscured quasars selected on the basis of mid-IR and optical photometry.Comment: Accepted for publication in ApJ; 14 pages, 9 figures, 2 tables; composite Type 1 and Type 2 quasar SEDs available at http://www.dartmouth.edu/~hickox/Hickox2017_QSO_SED_Table1.tx

The role of intermolecular coupling in the photophysics of disordered organic semiconductors: Aggregate emission in regioregular polythiophene

We address the role of excitonic coulping on the nature of photoexcitations in the conjugated polymer regioregular poly(3-hexylthiophene). By means of temperature-dependent absorption and photoluminescence spectroscopy, we show that optical emission is overwhelmingly dominated by weakly coupled H-aggregates. The relative absorbance of the 0-0 and 0-1 vibronic peaks provides a powerfully simple means to extract the magnitude of the intermolecular coupling energy, approximately 5 and 30 meV for films spun from isodurene and chloroform solutions respectively.Comment: 10 pages, 4 figures, published in Phys. Rev. Let

The short and longer term impacts of hate crimes experienced directly, indirectly and through the media

A longitudinal study (N = 774) explored the short and longer term impacts of anti-Lesbian, Gay, Bisexual, and Trans (LGBT) hate crime experienced directly, indirectly, and through the media. In the short term, being a victim (direct) or personally knowing of a hate crime victim (indirect) was positively associated with vulnerability, emotional responses, and behavioral intentions after reading about a hate crime. Direct victims were also less empathic toward other victims and engaged in more victim-blaming. A structural equation model showed direct experiences (via personal vulnerability and empathy) and media experiences (via group-threat and victim-blaming) to be cross-sectionally associated with behavioral intentions. Media experiences also had lasting demobilizing impacts on actual behaviors, again serially mediated by group-threat and victim-blaming. The findings highlight the emotional and behavioral impacts of hate crimes on both direct victims and on the wider LGBT community. They also raise questions about media reporting of hate crimes and the role of victim-blaming

COVID-19 Experiences, Behaviors, Beliefs, and Well-Being Among Students and Employees at a University In Rural Appalachia: A Cross-Sectional Study

Introduction: In response to the coronavirus disease (COVID-19) pandemic, most universities experienced drastic operational changes with shifts to online learning, work-from-home policies, and social distancing measures. These changes have caused concern for social isolation and mental health. Purpose: This cross-sectional study explores differences in COVID-19 experiences, behaviors, beliefs, and well-being among students and employees (faculty and staff) at a rural Appalachian university. Methods: Data were collected with an online anonymous survey in September-October 2020 using convenience sampling. The survey measured multiple domains including COVID-19-related 1) beliefs, 2) symptoms and diagnoses, 3) exposure and preventive behavior, and 4) social, mental, and financial health. Chi-square tests and linear regression models were used to determine differences in survey responses between students and employees. Results: The final sample used for analysis included 416 respondents. The majority of respondents believed COVID-19 was a serious disease and followed mask and social distancing guidelines, although employees were more likely to adhere to mask and social distancing guidelines compared to students. Most of the respondents (\u3e50%) reported feeling more stressed, anxious, and sad since the pandemic began. Students were more impacted by the pandemic compared to employees as measured by the mental, social, and financial impact scale. A limitation of this study was that convenience sampling was used instead of a probability sampling technique, which limits the inference that can be made from the results. Implications: There may be a need for greater mental health support among university employees and students. However, future studies should confirm these findings

SDSS-IV MaNGA: Identification of active galactic nuclei in optical integral field unit surveys

In this paper, we investigate 2727 galaxies observed by MaNGA as of June 2016 to develop spatially resolved techniques for identifying signatures of active galactic nuclei (AGN). We identify 303 AGN candidates. The additional spatial dimension imposes challenges in identifying AGN due to contamination from diffuse ionized gas, extra-planar gas and photoionization by hot stars. We show that the combination of spatially-resolved line diagnostic diagrams and additional cuts on H$\alpha$ surface brighness and H$\alpha$ equivalent width can distinguish between AGN-like signatures and high-metallicity galaxies with LINER-like spectra. Low mass galaxies with high specific star formation rates are particularly difficult to diagnose and routinely show diagnostic line ratios outside of the standard star-formation locus. We develop a new diagnostic -- the distance from the standard diagnostic line in the line-ratios space -- to evaluate the significance of the deviation from the star-formation locus. We find 173 galaxies that would not have been selected as AGN candidates based on single-fibre spectral measurements but exhibit photoionization signatures suggestive of AGN activity in the MaNGA resolved observations, underscoring the power of large integral field unit (IFU) surveys. A complete census of these new AGN candidates is necessary to understand their nature and probe the complex co-evolution of supermassive black holes and their hosts.Comment: 18 pages, 11 figures, accepted to MNRA

Many Uninsured Children Qualify for Medi-Cal or Healthy Families

Examines the public health insurance eligibility of children in California who did not have health insurance coverage for some or all of the year in 2002, to highlight the geographic variations in children's uninsured eligibility rates

Superoxide dismutase downregulation in osteoarthritis progression and end-stage disease

Oxidative stress is proposed as an important factor in osteoarthritis (OA). To investigate the expression of the three superoxide dismutase (SOD) antioxidant enzymes in OA. SOD expression was determined by real-time PCR and immunohistochemistry using human femoral head cartilage. SOD2 expression in Dunkin–Hartley guinea pig knee articular cartilage was determined by immunohistochemistry. The DNA methylation status of the SOD2 promoter was determined using bisulphite sequencing. RNA interference was used to determine the consequence of SOD2 depletion on the levels of reactive oxygen species (ROS) using MitoSOX and collagenases, matrix metalloproteinase 1 (MMP-1) and MMP-13, gene expression. All three SOD were abundantly expressed in human cartilage but were markedly downregulated in end-stage OA cartilage, especially SOD2. In the Dunkin–Hartley guinea pig spontaneous OA model, SOD2 expression was decreased in the medial tibial condyle cartilage before, and after, the development of OA-like lesions. The SOD2 promoter had significant DNA methylation alterations in OA cartilage. Depletion of SOD2 in chondrocytes increased ROS but decreased collagenase expression. This is the first comprehensive expression profile of all SOD genes in cartilage and, importantly, using an animal model, it has been shown that a reduction in SOD2 is associated with the earliest stages of OA. A decrease in SOD2 was found to be associated with an increase in ROS but a reduction of collagenase gene expression, demonstrating the complexities of ROS function

Chemical nucleation of diamond films

With the large differences in surface energy between film and substrate in combination with the low sticking coefficient of hydrocarbon radicals, nanocrystalline diamond growth on foreign substrates typically results in poor nucleation densities. A seeding technique is therefore required to realize pinhole-free and thin coalesced films. In this work, a chemical nucleation method for growth of diamond on nondiamond substrates based on 2,2-divinyladamantane is shown. After treating with the carbon-containing DVA, the chemically treated wafers were exposed to low-power-density plasma, known as the incubation phase, to facilitate the formation of diamond nucleation sites followed by a high-power-density growth regime to produce coalesced films. The resulting films demonstrate high crystallinity, whereas the Raman spectra suggest high-quality diamond with low sp² content