Persons with mental illness frequently encounter public stigma. This review seeks to clarify mental illness stigma and discuss methods for changing stigma in the real world. Following an overview of ...public stigma we discuss the main avenues recognised for changing stigma in the real world: protest, education and contact; and give examples of anti‐stigma strategies in practice. Finally, we discuss the most effective method, contact, in greater detail through three different areas where anti‐stigma efforts have been focused: disclosure, children, and patient‐based programs. Anti‐stigma programs that focus upon the most effective ways to diminish stigma will help bring about change in the stigmatising attitudes of the general public.
Formation of double compact objects Kalogera, V.; Belczynski, K.; Kim, C. ...
Physics reports,
04/2007, Letnik:
442, Številka:
1
Journal Article
Recenzirano
Current observations of double neutron stars provide us with a wealth of information that we can use to investigate their evolutionary history and the physical conditions of neutron star formation. ...Understanding this history and formation conditions further allow us to make theoretical predictions for the formation of other double compact objects with one or two black hole (BH) components and assess the detectability of such systems by ground-based gravitational-wave (GW) interferometers. In this paper we summarize our group's body of work in the past few years and we place our conclusions and current understanding in the framework of other work in this area of astrophysical research.
As a first step toward understanding the angular momentum evolution history of black holes in merging black hole/neutron star binaries, we perform population synthesis calculations to track the ...distribution of accretion histories of compact objects in such binaries. We find that there are three distinct processes that can possibly contribute to the black hole spin magnitude: a birth spin for the black hole, imparted at either (1) the collapse of a massive progenitor star to a black hole or (2) the accretion-induced collapse of a neutron star to a black hole, and (3) an accretion spin-up when the already formed black hole (via processes 1 or 2) goes through an accretion episode (through an accretion disk or a common-envelope phase). Our results show that, with regard to accretion-induced spin-up in merging BH-NS binaries (method 3 above), only accretion episodes associated with common-envelope phases and hypercritical accretion rates occur in the formation history of merging black hole/neutron star binaries. Lacking unambiguous experimental information about BH birth spins (i.e., regarding the results of processes 1 and 2), we choose two fiducial values for the BH birth angular momentum parameter a = J/M super(2), consistent with observations of (1) NS birth spins (a 0) and (2) X-ray binaries (a = 0.5). Using these two fiducial values and a conservative upper bound on the specific angular momentum of accreted matter, we discuss the expected range of black hole spins in the binaries of interest. We conclude with comments on the significance of these results for ground-based gravitational wave searches of inspiral signals from black hole binaries.
Many signal processing applications require estimation of time-varying sparse signals, potentially with the knowledge of an imperfect dynamics model. In this paper, we propose an algorithm for ...dynamic filtering of time-varying sparse signals based on the sparse Bayesian learning (SBL) framework. The key idea underlying the algorithm, termed SBL-DF, is the incorporation of a signal prediction generated from a dynamics model and estimates of previous time steps into the hyperpriors of the SBL probability model. The proposed algorithm is online, robust to imperfect dynamics models (due to the propagation of dynamics information through higher-order statistics), robust to certain undesirable dictionary properties such as coherence (due to properties of the SBL framework), allows the use of arbitrary dynamics models, and requires the tuning of fewer parameters than many other dynamic filtering algorithms do. We also extend the fast marginal likelihood SBL inference procedure to the informative hyperprior setting to create a particularly efficient version of the SBL-DF algorithm. Numerical simulations show that SBL-DF converges much faster and to more accurate solutions than standard SBL and other dynamical filtering algorithms. In particular, we show that SBL-DF outperforms state of the art algorithms when the dictionary contains the challenging coherence and column scaling structure found in many practical applications.
We combine a large database of population synthesis calculations, models for the star formation history of the universe, and a simple selection model for bursts to predict short GRB detection rates, ...redshift distributions, and host galaxy distributions. We compare our space of possible models with observations of short GRBs (rates and redshifts) and, when assuming short GRBs are produced from NS-NS binaries, the current estimates for NS-NS merger rates from close binary pulsars in the Milky Way. Whether short GRBs are assumed to arise from BH-NS or NS-NS mergers, we conclude that a fraction of models are in agreement with available short GRB and binary pulsar observations. We do not need to introduce artificial models with long delay times. Most commonly, models produce mergers preferentially in spiral galaxies if short GRBs arise from NS-NS mergers alone. On the other hand, typically BH-NS mergers can also occur in elliptical galaxies, in agreement with existing observations. We expect that a higher proportion of short GRBs should occur at moderate to high redshift (e.g., image) than has presently been observed, in agreement with recent observations which suggest a strong selection bias toward successful follow-up of low-redshift short GRBs. Finally, if we add plausible additional assumptions about what BH-NS mergers could produce short GRBs based on the work of Belczynski and coworkers, then we expect only a small fraction of BH-NS models could be consistent with all current available data.
Due to the economic, social, and health consequences of burnout, farmer burnout is receiving increased attention in the media and in contemporary research. In this systematic review and narrative ...synthesis, we aim to evaluate and synthesise the current state of the international evidence for the prevalence of farmer burnout. We developed and applied a search strategy to target studies that examined the prevalence of burnout among farmers of any farming type, gender, and nationality. Combined with secondary and grey literature searching, this resulted in 811 search results. Twenty-three full texts were screened which resulted in nine eligible studies consisting of seven cross-sectional studies, one longitudinal study, and one RCT. We applied the STROBE checklist for quality appraisal, and most studies had a low risk of bias. Across North American, European and Australian studies using cutting points, the average prevalence of severe burnout in farmers was 13.72%. The prevalence rate was higher in New Zealand (25%) and Morocco (18.96%). Compared to non-farmers, farmers experienced higher overall burnout, and higher exhaustion, cynicism and professional efficacy. Gender differences indicated that women experience higher burnout than males. Associated factors included farming as primary occupation, being a dairy farmer, and work stress. Findings indicate the characteristics of farmers especially at risk of burnout which could inform the development of future research and supports to ameliorate farmer burnout. Results also highlight the limitations of the evidence for farmer burnout including the lack of standardised burnout classification methods, the potential for response-bias when examining gender issues, and the influence of socio-economic and agricultural policy in the international evidence.
•In this systematic review, we present current international literature on the prevalence of farmer burnout.•Severe burnout in farmers ranged from 9.8%-13.72% depending on the measure used, cut-off points, and location•Severe burnout was significantly higher in farmers compared to non-farmer populations.•Burnout was higher in female farmers and in farmers outside Europe and North America.•Factors associated with burnout were dairy farming, work stress, workload, health and traditional (non-diversified) farming
The detection of orbital eccentricity for a binary black hole system via gravitational waves is a key signature to distinguish between the possible binary origins. The identification of eccentricity ...has been difficult so far due to the limited availability of eccentric gravitational waveforms over the full range of black hole masses and eccentricities. Here we evaluate the eccentricity of five black hole mergers detected by the LIGO and Virgo observatories using the TEOBResumS-DALI, TEOBResumS-GIOTTO, and TEOBResumSP models. This analysis studies eccentricities up to 0.6 at the reference frequency of 5 Hz and incorporates higher-order gravitational-wave modes critical to model emission from highly eccentric orbits. The binaries have been selected due to previous hints of eccentricity or due to their unusual mass and spin. While other studies found marginal evidence for eccentricity for some of these events, our analyses do not favor the incorporation of eccentricity compared to the quasi-circular case. While lacking the eccentric evidence of other analyses, we find our analyses marginally shifts the posterior in multiple parameters for several events when allowing eccentricity to be nonzero.
ABSTRACT
Observations by LIGO–Virgo of binary black hole mergers suggest a possible anticorrelation between black hole mass ratio (q = m2/m1) and the effective inspiral spin parameter χeff, the ...mass-weighted spin projection on to the binary orbital angular momentum. We show that such an anticorrelation can arise for binary black holes assembled in active galactic nuclei (AGNs) due to spherical and planar symmetry-breaking effects. We describe a phenomenological model in which (1) heavier black holes live in the AGN disc and tend to spin-up into alignment with the disc; (2) lighter black holes with random spin orientations live in the nuclear spheroid; (3) the AGN disc is dense enough to rapidly capture a fraction of the spheroid component, but small in radial extent to limit the number of bulk disc mergers; (4) migration within the disc is non-uniform, likely disrupted by feedback from migrators or disc turbulence; (5) dynamical encounters in the disc are common and preferentially disrupt binaries that are retrograde around their centre of mass, particularly at stalling orbits, or traps. Comparisons of predictions in (q, χeff) parameter space for the different channels may allow us to distinguish their fractional contributions to the observed merger rates.
Supermassive black holes (SMBHs) presumably grow through numerous mergers throughout cosmic time. During each merger, SMBH binaries are surrounded by a circumbinary accretion disk that imposes a ...significant (~104 G for a binary of 108 M ) magnetic field. The motion of the binary through that field will convert the field energy to Poynting flux, with a luminosity ~1043 erg s--1 (B/104 G)2(M/108 M )2, some of which may emerge as synchrotron emission at frequencies near 1 GHz where current and planned wide-field radio surveys will operate. We find that the short timescales of many mergers will limit their detectability with most planned blind surveys to <1 per year over the whole sky, independent of the details of the emission process and flux distribution. Including an optimistic estimate for the radio flux makes detection even less likely, with <0.1 mergers per year over the whole sky. However, wide-field radio instruments may be able to localize systems identified in advance of merger by gravitational waves. Further, radio surveys may be able to detect the weaker emission produced by the binary's motion as it is modulated by spin-orbit precession and inspiral well in advance of merger.
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