AGN and their host galaxies in the local Universe: two mass independent Eddington ratio distribution functions characterize black hole growth

We use a phenomenological model to show that black hole growth in the local Universe (z < 0.1) can be described by two separate, mass independent Eddington ratio distribution functions (ERDFs). We assume that black holes can be divided into two independent groups: those with radiatively efficient accretion, primarily hosted by optically blue and green galaxies, and those with radiatively inefficient accretion, which are mainly found in red galaxies. With observed galaxy stellar mass functions as input, we show that the observed AGN luminosity functions can be reproduced by using mass independent, broken power law shaped ERDFs. We use the observed hard X-ray and 1.4 GHz radio luminosity functions to constrain the ERDF for radiatively efficient and inefficient AGN, respectively. We also test alternative ERDF shapes and mass dependent models. Our results are consistent with a mass independent AGN fraction and AGN hosts being randomly drawn from the galaxy population. We argue that the ERDF is not shaped by galaxy-scale effects, but by how efficiently material can be transported from the inner few parsecs to the accretion disc. Our results are incompatible with the simplest form of mass quenching where massive galaxies host higher accretion rate AGN. Furthermore, if reaching a certain Eddington ratio is a sufficient condition for maintenance mode, it can occur in all red galaxies, not just the most massive ones.Comment: 33 pages, 15 figures, accepted for publication in ApJ, Fig. 6 shows the main resul

The systematic search for z≳5 active galactic nuclei in the Chandra Deep Field South

We investigate early black hole (BH) growth through the methodical search for z≳5 active galactic nuclei (AGN) in the Chandra Deep Field South. We base our search on the Chandra 4-Ms data with flux limits of 9.1×10−18 (soft, 0.5-2 keV) and 5.5×10−17 erg s−1 cm−2 (hard, 2-8 keV). At z∼5, this corresponds to luminosities as low as ∼1042 (∼1043) erg s−1 in the soft (hard) band and should allow us to detect Compton-thin AGN with MBH>107 M⊙ and Eddington ratios >0.1. Our field (0.03 deg2) contains over 600z∼5 Lyman Break Galaxies. Based on lower redshift relations, we would expect ∼20 of them to host AGN. After combining the Chandra data with Great Observatories Origins Deep Survey (GOODS)/Advanced Camera for Surveys (ACS), CANDELS/Wide Field Camera 3 and Spitzer/Infrared Array Camera data, the sample consists of 58 high-redshift candidates. We run a photometric redshift code, stack the GOODS/ACS data, apply colour criteria and the Lyman Break Technique and use the X-ray Hardness Ratio. We combine our tests and using additional data find that all sources are most likely at low redshift. We also find five X-ray sources without a counterpart in the optical or infrared which might be spurious detections. We conclude that our field does not contain any convincing z≳5 AGN. Explanations for this result include a low BH occupation fraction, a low AGN fraction, short, super-Eddington growth modes, BH growth through BH-BH mergers or in optically faint galaxies. By searching for z≳5 AGN, we are setting the foundation for constraining early BH growth and seed formation scenario

A Program Evaluation of the Behavioral Intervention Component of the Virginia Tiered Systems of Support in Three Middle Schools

The Virginia Tiered Systems of Support (VTSS) represents the merger of the behavioral side Positive Behavioral Supports (PBIS) and the academic side Response to Interventions (RtI) (Mann & Leutscher, 2014). VTSS is the Commonwealth of Virginia\u27s adaptation of the federally required systemic response program schools are expected to adopt to address the behavioral and academic needs of students (Landers, Courtade, & Ryndak, 2012; Prasse et al., 2012). The development of specific implementation guidelines has been assigned to local levels of leadership. Thus, VTSS programming differences are common between both districts and schools. The purpose of this study is to assess the implementation levels of the behavioral components of three middle schools within the same school district. Three middle schools were selected for this study. The schools operate in the same school district and are separated by approximately ten miles. The study revealed that the schools varied greatly in their interpretation and facilitation of VTSS despite having access to similar resources and external supports. The degrees of behavioral programming implementation and the types of behavioral interventions varied by school location, and these differences are related a variety of different variables: from each school-based VTSS teams\u27 diverse interpretation of VTSS objectives to insufficient faculty buy-in of VTSS-recommended interventions. Additionally, the study revealed that the schools desire to correct the implementation issues and seek to have more central office-driven standardization in programming among their locations

THE IMPACT OF METAPHOR IN MENTAL ILLNESS STIGMA

A growing body of research indicates that differing metaphors can influence perception and effectively shape the way we think about the world around us (Lakoff, 2012; Panzeri & Paula, 2020; Thibodeau et al., 2009; Vallis & Inayatullah, 2001). The present study investigates whether different metaphors can influence perceptions of mental illness, specifically in regards to Schizophrenia. Participants were instructed to read a short vignette depicting a diagnosis of a Schizophrenic patient in terms of either a "battle" with the illness or a "journey". In order to obtain results, we measured dependency, preference for social distance, fear response, empathy/ emotional response, and anger. Results of the present study indicated that there was no significant relationship between metaphor and perceptions of a Schizophrenia diagnosis. With this being said, there was a significant effect of gender identity on perceptions of the patient. Men displayed more stigma towards patients with Schizophrenia than did women. Based on the findings of this study, future researchers may want to hone in on gender differences in perception of mental illness and further the existing research on metaphor as it pertains to mental illness.Purchase College SUNYPsychologyBachelor of ArtsToskos, Alexia C

A population of luminous accreting black holes with hidden mergers

Major galaxy mergers are thought to play an important part in fuelling the growth of supermassive black holes. However, observational support for this hypothesis is mixed, with some studies showing a correlation between merging galaxies and luminous quasars and others showing no such association. Recent observations have shown that a black hole is likely to become heavily obscured behind merger-driven gas and dust, even in the early stages of the merger, when the galaxies are well separated (5 to 40 kiloparsecs). Merger simulations further suggest that such obscuration and black-hole accretion peaks in the final merger stage, when the two galactic nuclei are closely separated (less than 3 kiloparsecs). Resolving this final stage requires a combination of high-spatial-resolution infrared imaging and high-sensitivity hard-X-ray observations to detect highly obscured sources. However, large numbers of obscured luminous accreting supermassive black holes have been recently detected nearby (distances below 250 megaparsecs) in X-ray observations. Here we report high-resolution infrared observations of hard-X-ray-selected black holes and the discovery of obscured nuclear mergers, the parent populations of supermassive-black-hole mergers. We find that obscured luminous black holes (bolometric luminosity higher than 2x10^44 ergs per second) show a significant (P<0.001) excess of late-stage nuclear mergers (17.6 per cent) compared to a sample of inactive galaxies with matching stellar masses and star formation rates (1.1 per cent), in agreement with theoretical predictions. Using hydrodynamic simulations, we confirm that the excess of nuclear mergers is indeed strongest for gas-rich major-merger hosts of obscured luminous black holes in this final stage.Comment: To appear in the 8 November 2018 issue of Nature. This is the authors' version of the wor

A species-wide inventory of NLR genes and alleles in Arabidopsis thaliana

Infectious disease is both a major force of selection in nature and a prime cause of yield loss in agriculture. In plants, disease resistance is often conferred by nucleotide-binding leucine-rich repeat (NLR) proteins, intracellular immune receptors that recognize pathogen proteins and their effects on the host. Consistent with extensive balancing and positive selection, NLRs are encoded by one of the most variable gene families in plants, but the true extent of intraspecific NLR diversity has been unclear. Here, we define a nearly complete species-wide pan-NLRome in Arabidopsis thaliana based on sequence enrichment and long-read sequencing. The pan-NLRome largely saturates with approximately 40 well-chosen wild strains, with half of the pan-NLRome being present in most accessions. We chart NLR architectural diversity, identify new architectures, and quantify selective forces that act on specific NLRs and NLR domains. Our study provides a blueprint for defining pan-NLRomes

The New Normal of Virtual Team Cohesion – a Qualitative Study to Investigate the Impact of COVID-19

A strong sense of virtual team cohesion can have a variety of positive effects, such as increased performance or self-esteem. For several decades information systems researchers have been studying both task and social cohesion and how to maintain such cohesion in the virtual. However, since one of the major challenges of the pandemic is dealing with feelings of social isolation, research outlines that COVID-19 had and still has a significant impact on virtual team cohesion. Our study examines the “new normal” of virtual team cohesion i.e., how virtual team cohesion strengthening measures have changed in times of the pandemic. To this end, our study presents the findings of a qualitative study with 26 individuals. We were able to shed light on how such measures changed on-the-job, in breaktimes, and after work. Therefore, we provide insights in the “new normal” of virtual team cohesion, which can inform research and practice