bluuebunny/crossref_metadata_2025_split huggingface dataset:
Personality Characteristics and Acute Symptom Response Predict Chronic Symptoms After Mild Traumatic Brain Injury
Authors: Parker Hillary A. , Ranson Jana , McCrea Michael A. , Hoelzle James , deRoon-Cassini Terri , Nelson Lindsay D. 
Published: January 2021

AbstractObjective:Despite consensus that personality influences mild traumatic brain injury (mTBI) recovery, it has been underexamined. We evaluated the extent to which diverse personality and psychiatric symptom dimensions predict mTBI recovery.Methods:This prospective cohort study involved psychological assessments of hospital patients with mTBI (n = 75; median = 2 days post-injury, range = 0–12 days) and orthopedic trauma controls (OTC; n = 79) who were used for comparison in mediation modeling. Chronic symptoms were evaluated at 3 months after mTBI (n = 50) using the Sport Concussion Assessment Tool (SCAT) symptom checklist. Linear regression analyses were used to identify the predominant predictors of chronic symptoms in mTBI. Modern mediation analyses tested the hypothesis that personality traits predict chronic symptoms through acute psychological response to injury.Results:In mTBI, trait psychoticism directly predicted chronic mTBI symptoms and was the strongest personality predictor overall. Furthermore, an internalizing personality dimension emphasizing negative affect/emotionality and detachment predicted chronic mTBI symptoms indirectly through enhancement of acute somatic complaints. In OTC, internalizing personality acted through the same mediator as in mTBI, whereas the effect of psychoticism was also mediated through acute somatic complaints. There was varying support for a moderated direct effect of personality traits at low levels of positive emotionality across models.Conclusion:These causal models provide novel insights about the role of personality in mTBI symptom recovery, highlighting the complexity of how psychological processes may interact to affect recovery and revealing that some of these processes may be non-specific to brain injury.
Young learners’ L2 English after the onset of instruction: longitudinal development of L2 proficiency and the role of individual differences
Authors: De Wilde Vanessa , Brysbaert Marc , Eyckmans June 
Published: January 2021

AbstractIn this study we investigated 107 young learners’ L2 English receptive vocabulary knowledge and speaking skills at two points in time, before and after the onset of instruction. We also investigated the role of several individual difference variables: out-of-school exposure to English, length of instruction, analytic reasoning ability, working memory, L1 vocabulary knowledge and prior L2 knowledge. Results show that L2 English proficiency in receptive vocabulary knowledge and speaking skills greatly improved over time and that the effects of schooling and contextual learning are largely additive. The main predictor of the children's proficiency at time 2 was their L2 prior knowledge, which they had acquired through contextual language learning before getting formal education. When considering the other variables that predicted L2 proficiency, the contribution of internal variables (L1 vocabulary size and working memory) was considerably smaller than that of external variables (out-of-school exposure and length of instruction).
Optical spectroscopy of nearby type1-LINERs
Authors: Cazzoli Sara , Márquez Isabel , Masegosa Josefa , del Olmo Ascensión , Pović Mirjana , González-Martín Omaira , Balmaverde Barbara , Hernández-García Lorena , García-Burillo Santiago 
Published: January 2021

AbstractWe present the highlights from our recent study of 22 local (z < 0.025) type-1 LINERs from the Palomar Survey, on the basis of optical long-slit spectroscopic observations taken with TWIN/CAHA, ALFOSC/NOT and HST/STIS. Our goals were threefold: (a) explore the AGN-nature of these LINERs by studying the broad (BLR-originated) Hαλ 6563 component; (b) derive a reliable interpretation for the multiple narrow components of emission lines by studying their kinematics and ionisation mechanism (via standard BPTs); (c) probe the neutral gas in the nuclei of these LINERs for the first time. Hence, kinematics and fluxes of a set of emission lines, from Hβ λ4861 to [SII]λλ 716,6731, and the NaDλλ5890,5896 doublet in absorption have been modelled and measured, after the subtraction of the underlying light from the stellar component.
Recent results of measuring black hole masses via reverberation mapping
Authors: Kaspi Shai 
Published: January 2021

AbstractOver the past three decades more than 100 Active Galactic Nuclei (AGNs) were measured using the reverberation mapping technique. This technique uses the response of the line emission in the Broad Line Region (BLR) to continuum emission variation and yields a measure for the distance of the BLR from the central Black Hole (BH). This in turn is used to measure the BH’s mass. Almost all of these measurements are of low-luminosity AGNs while for quasars with luminosities higher than 1046 rg s−1 there are hardly any attempts of reverberation mapping. This contribution reports on recent results from a two-decades campaigns to measure the BH mass in high-luminosity quasars using the reverberation mapping technique. BLR distance from the BH, BH mass, and AGN UV luminosity relations over eight orders of magnitude in luminosity are presented, pushing the luminosity limit to the highest point so far.
Revisiting old (AGN) friends - what’s changed in their spectral looks
Authors: Winkler Hartmut 
Published: January 2021

AbstractActive Galactic Nuclei (AGN) have long been known to be variable, but the amplitude, timescale and nature of these changes can often differ dramatically from object to object. The richest source of information about the properties of AGN and the physical processes driving these remains the optical spectrum. While this spectrum has remained remarkably steady over decades for some AGN, other objects, referred to as Changing Look AGN, have experienced a comprehensive spectral transformation. Developments in the detection technology have enabled detailed probing in other wavebands, highlighting for example often quite different variability patterns for high energy emission. This paper explores the current characteristics of some long-known (and almost forgotten) Seyfert galaxies. It compares their present optical spectral properties, determined from recent observations at the South African Astronomical Observatory, with those from much earlier epochs. It furthermore considers the implication of the changes that have taken place, alternatively the endurance of specific spectral features, on our understanding of the mechanisms of the observed targets in particular, and on AGN models in general.
Role of active galactic nuclei and flow of relativistic jets
Authors: Tassama Abdissa , Biressa Tolu 
Published: January 2021

AbstractThe astrophysics of Active Galactic Nuclei (AGN) is one of the long outstanding issues in searches among the scientific communities raised with diverse perspectives like nebula, quasars, etc some decades ago. Currently, this exotic system is at least understood as the center of an active galaxy. Thus, the consensus of this recent theory has opened up a number of research issues for the progress of astrophysical science including how the hosting galaxy evolves with the AGN, how matter and energy flow towards and outwards, etc. Moreover, most of the AGNs possess Supermassive Black Holes (SMBHs) and accrete matter at a very high rate as current observations report. Consequently, both observations of electromagnetic (EM) spectrum and Gravity Waves (GWs) will considered to provide complementary information about the AGNs and the roles in their environments including black holes in their centers, outflow and inflow of matter-energy. Interested with this background rationale, we study the mechanisms of AGN interaction with its environment and flow of relativistic jets where General Relativistic (GR) Magneto-Hydrodynamic (MHD) equations are being considered. The solutions of the field equations are treated with a metric that involves charged systems for the possible relativistic jets including accretions. Then, numerical data is being generated using the latest version Mathematic software. Finally, the theoretical data is being compared with that of observation for validation of the model.
The role of active galactic nuclei in galaxy evolution in terms of radial pressure
Authors: Tolu Biressa , Feyissa Abate 
Published: January 2021

AbstractIrrespective of whether Active Galactic Nuclei (AGN) is cored with Supermassive Black Holes (SMBH) or not, there is a general consensus that observations indicate that the AGN plays fundamental role in galaxy evolution. The accretion disc powered fueling of the AGN and counter-feedback on its environment in the form of stress-energy-momentum along the radial component and an associated polodial jets seems viable model. On the theoretical ground there is no unified theory that compromise the observations. But there are pull of such diverse physics simulated to describe the observational works. So, there is unsettled theoretical framework how the activity of the AGN plays role in the evolution of host galaxy. Motivated by this we studied the role of AGN on its host galaxy evolution where General relativistic (GR) Magnetohydrodynamics (MHD) equation is considered to derive radial pressure that invokes star forming cold gases. Methodologically the central engine of the AGN is considered with SMBH/pseudo-SMBH. Locally, around the AGN, Reissner-Nordstrom-de Sitter metric is considered that reduces to the Schwarzschoild-de Sitter (SdS) background. Geometrically, a simple spherical geometry is superimposed with central disc structure assumed by cored void mass ablating model. The results of the work indicates that the AGN plays role in galaxy evolution, especially in the nearby environment. Also we report that the adjacent envelope to the AGN seems quiet with no activity in formation.
Detailed characterisation of LINERs and retired galaxies in the local universe
Authors: Mazengo Daudi T. , Pović Mirjana , Jiwaji Noorali T. , Sunzu Jefta M. 
Published: January 2021

AbstractWe present a detailed characterisation of physical properties of low-ionization nuclear emission-line regions (LINERs) and retired galaxies (RGs) in the local universe for redshift range 0 <z< 0.4 and two subrangesz< 0.4 and 0.1 <z< 0.4. Furthermore, we test the effectiveness of WHAN diagnostic diagram in separating the two populations. We used photometric data, public spectroscopic data and morphological classification from SDSS-DR8, MPA-JHU SDSS-DR8 catalogue and Galaxy Zoo survey, respectively. We studied the distribution of LINERs, RGs and AGN-LINERs in relation to luminosity, stellar mass, star formation rate (SFR), colour, and their location on the SFR-stellar mass and colour-stellar mass diagrams. We then studied the morphologies of both populations. Results have shown that for higher redshift range, AGN-LINERs have higher apparentgmagnitude, SFRs and dominate on/above the main sequence (MS) of star formation compared to RGs. However, both populations have similar stellar mass and luminosity distributions at all redshift ranges hence suggesting a significant difference in terms of star formation of RGs and AGN-LINERs with redshift. However, larger and more complete samples of LINERs are needed from the future surveys (e.g., LSST) and missions (e.g., JWST) to study in more details the properties of RGs and AGN-LINERs and find alternative methods of separating the two populations, since using simply WHAN diagram from our study we do not find it to be effective for separating the two populations.
Exploring the X-ray universe via timing: mass of the active galactic nucleus black hole XMMUJ134736.6+173403
Authors: Šrámková Eva , Goluchová K. , Török G. , Abramowicz Marek A. , Stuchlík Z. , Horák Jiří 
Published: January 2021

AbstractA strong quasi-periodic modulation has recently been revealed in the X-ray flux of the X-ray source XMMUJ134736.6+173403. The two observed twin-peak quasiperiodic oscillations (QPOs) exhibit a 3:1 frequency ratio and strongly support the evidence for the presence of an active galactic nucleus black hole (AGN BH). It has been suggested that detections of twin-peak QPOs with commensurable frequency ratios and scaling of their periods with BH mass could provide the basis for a method intended to determine the mass of BH sources, such as AGNs. Assuming the orbital origin of QPOs, we calculate the upper and lower limit on the AGN BH mass M, reaching M ≍ 107–109M⊙. Compared to mass estimates of other sources, XMMUJ134736.6+173403 appears to be the most massive source with commensurable QPO frequencies, and its mass represents the current observational upper limit on the AGN BH mass obtained from the QPO observations.
Probing black hole - host galaxy scaling relations with obscured type II AGN
Authors: Baron Dalya 
Published: January 2021

AbstractThe scaling relations between supermassive black holes and their host galaxy properties are of fundamental importance in the context black hole-host galaxy co-evolution throughout cosmic time. Beyond the local universe, such relations are based on black hole mass estimates in type I AGN. Unfortunately, for this type of objects the host galaxy properties are more difficult to obtain since the AGN dominates the observed flux in most wavelength ranges. In this poster I will present a new correlation we discovered between the narrow L([OIII])/L(Hβ) line ratio and the FWHM(broad Hα). This scaling relation ties the kinematics of the gas clouds in the broad line region to the ionization state of gas in the narrow line region, connecting the properties of gas clouds kiloparsecs away from the black hole to material gravitationally bound to it on sub-parsec scales. This relation can be used to estimate black hole masses from narrow emission lines only, and thus brings the missing piece required to estimate black hole masses in obscured type II AGN. Using this technique, we estimate the black hole mass of about 10,000 type II AGN, and present, for the first time, M(BH)-sigma and M(BH)-M(stars) scaling relations for this population. These relations are remarkably consistent with those observed for type I AGN, suggesting that this new method may perform as reliably as the classical estimate used in non-obscured type I AGN. These findings open a new window for studies of black hole-host galaxy co-evolution throughout cosmic time.
Optical variability of faint quasars
Authors: Ewnu Kassa Endalamaw 
Published: January 2021

AbstractThe variability properties of a quasar sample, spectroscopically complete to magnitude J = 22.0, are investigated on a time baseline of 2 yr, using three different photometric bands (U, J and F). The original sample was obtained using a combination of different selection criteria: colours, slitless spectroscopy and variability, based on a time baseline of 1 yr. The main goals of this work are two-fold: first, to derive the percentage of variable quasars on a relatively short time baseline; secondly, to search for new quasar candidates, missed by the other selection criteria, and thus to estimate the completeness of the spectroscopic sample. In order to achieve these goals, we have extracted all the candidate variable objects from a sample of about 1800 stellar or quasi-stellar objects with limiting magnitude J = 22.50 over an area of about 0.50 deg2. We find that > 65% of all the objects selected as possibly variable are either confirmed quasars or quasar candidates, on the basis of their colours. This percentage increases even further if we exclude from our lists of variable candidates a number of objects equal to that expected on the basis of ‘contamination’ induced by our photometric errors. The percentage of variable quasars in the spectroscopic sample is also high, reaching about 50%. On the basis of these results, we can estimate that the incompleteness of the original spectroscopic sample is < 12%. We conclude that variability analysis of data with small photometric errors can be successfully used as an efficient and independent (or at least auxiliary) selection method in quasar surveys, even when the time baseline is relatively short. Finally, when corrected for the different intrinsic time lags corresponding to a fixed observed time baseline, our data do not show a statistically significant correlation between variability and either absolute luminosity or redshift.
Measuring therapist cognitions contributing to therapist drift: a qualitative study
Authors: Rameswari Tiffany , Hayes Brett , Perera-Delcourt Ramesh 
Published: January 2021

AbstractTherapist beliefs have been identified as a contributing factor to ‘therapist drift’ in cognitive behavioural therapy (CBT). Scales have been developed to measure therapist beliefs, but none explicitly measure ‘therapy-interfering cognitions’, and there is no research on their usage. The aim of this study was to explore how best to conceptualise such a scale’s content and usage, based on clinicians’ perceptions and experiences of current scales. Three focus groups were conducted, involving 12 participants who were either qualified or trainee CBT therapists. Transcripts were analysed using thematic analysis. Four main themes were generated: (1) The Awareness and Importance of Cognitions, (2) Factors Fuelling Therapist Cognitions, (3) Addressing Therapist Cognitions, and (4) Using the Scale. Participants thought it important to be aware of and address therapist cognitions (not underlying beliefs). Participants emphasised that therapist cognitions are not just products of the individual, but are influenced by external factors. A scale could enable therapists to do better work through reflective practice, as long as it was used not just to identify cognitions but also to support changes in therapist behaviour. A scale could also meet a perceived need for making this part of routine practice. However, participants discussed how therapists might have reservations about disclosing cognitions in this way. Recommendations for current practice, and future research developing such a scale, are made.Key learning aims(1)To describe the phenomenon of therapist drift, and the contributions of therapist beliefs to this.(2)To explore the usage of current scales for measuring therapist beliefs.(3)To understand, based on therapist experience, how to address therapist beliefs in current practice using scales.
Self-Efficacy and Citizen Engagement in Development: Experimental Evidence from Tanzania
Authors: Lieberman Evan , Zhou Yang-Yang 
Published: January 2021

AbstractRecent studies of efforts to increase citizen engagement in local governance through information campaigns report mixed results. We consider whether low levels of self-efficacy beliefs limit engagement, especially among poor citizens in poor countries. Citizens may be caught in an “efficacy trap” which limits their realization of better public goods provision. We describe results from a series of experimental studies conducted with over 2,200 citizens in rural Tanzania, in which we compare the effects of standard information campaigns with Validated Participation (VP), an intervention designed to socially validate citizens’ participation. We implement a staged approach to experimental research, seeking to balance ethical and cost concerns about field experimentation. In our main analyses, we find that VP did not lead to increased levels of self-efficacy or more active citizen behaviors relative to standard informational treatments. Nonetheless, we find some promising evidence for VP in a follow-up qualitative study with teachers. We conclude by discussing lessons from this research and directions for future investigation of the possible role of self-efficacy traps in development.
The Effects of Source Cues and Issue Frames During COVID-19
Authors: Case Chandler , Eddy Christopher , Hemrajani Rahul , Howell Christopher , Lyons Daniel , Sung Yu-Hsien , Connors Elizabeth C. 
Published: January 2021

AbstractThe health and economic outcomes of the COVID-19 pandemic will in part be determined by how effectively experts can communicate information to the public and the degree to which people follow expert recommendation. Using a survey experiment conducted in May 2020 with almost 5,000 respondents, this paper examines the effect of source cues and message frames on perceptions of information credibility in the context of COVID-19. Each health recommendation was framed by expert or nonexpert sources, was fact- or experience-based, and suggested potential gain or loss to test if either the source cue or framing of issues affected responses to the pandemic. We find no evidence that either source cue or message framing influence people’s responses – instead, respondents’ ideological predispositions, media consumption, and age explain much of the variation in survey responses, suggesting that public health messaging may face challenges from growing ideological cleavages in American politics.
A New Data‐Driven Bayesian Inversion of Fluvial Topography Clarifies the Tectonic History of the Corinth Rift and Reveals a Channel Steepness Threshold
Authors: Gallen S. F. , Fernández‐Blanco D. 
Published: January 2021

AbstractLandscape evolution models that invert topography for rock uplift can improve our understanding of both tectonic and geomorphic processes when properly constrained with data. Here we present a flexible, data‐driven Bayesian approach to invert fluvial topography for tectonic and geomorphic model parameters and apply it to a case study, the uplifting footwall of the Corinth Rift, Greece. We invert transient river profiles and up‐flexed marine terraces to resolve seven unknown parameters in a regional‐to‐flexural uplift tectonic model and the stream power incision model. The best‐fit tectonic parameters are consistent with independent data and predict block uplift rates of ∼0.1 mm yr−1 that changed to flexural uplift rates of ∼1.6 mm yr−1 at ∼0.6 Ma, as the master normal fault initiated. Similarly, the best‐fit geomorphic parameters predict sediment flux consistent with the offshore record and erodibility consistent with previous studies. However, the drainage area exponent, , of ∼2, and slope exponent, , of ∼7, are unusually high, indicating a threshold channel steepness where fluvial topography is largely insensitive to rock uplift rate >0.05 mm yr−1. Analysis indicates channels narrow to accommodate enhanced uplift rates, but channel narrowing only partially explains our results, suggesting that other processes not accounted for in the generic stream power model are also relevant to bedrock river incision in Corinth. Our results help clarify the tectonic and geomorphic evolution of the Corinth Rift, have important implications for studies that invert topography for rock uplift histories, and provide insight into potential limitations of some long‐term river incision models.