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In recent years, the discovery of massive quasars at
has provided a striking challenge to our understanding of the origin and growth of supermassive black holes in the early Universe. Mounting observational and theoretical evidence indicates the viability of massive seeds, formed by the collapse of supermassive stars, as a progenitor model for such early, massive accreting black holes. Although considerable progress has been made in our theoretical understanding, many questions remain regarding how (and how often) such objects may form, how they live and die, and how next generation observatories may yield new insight into the origin of these primordial titans. This review focusses on our present understanding of this remarkable formation scenario, based on the discussions held at the Monash Prato Centre from November 20 to 24, 2017, during the workshop ‘Titans of the Early Universe: The Origin of the First Supermassive Black Holes’.
To describe the modification and validation of an existing instrument, the Environment and Policy Assessment and Observation (EPAO), to better capture provider feeding practices.
Modifications to the EPAO were made, validity assessed through expert review, pilot tested and then used to collect follow-up data during a two-day home visit from an ongoing cluster-randomized trial. Exploratory factor analysis investigated the underlying factor structure of the feeding practices. To test predictive validity of the factors, multilevel mixed models examined associations between factors and child’s diet quality as captured by the Healthy Eating Index-2010 (HEI-2010) score (measured via the Dietary Observation in Childcare Protocol).
Family childcare homes (FCCH) in Rhode Island and North Carolina, USA.
The modified EPAO was pilot tested with fifty-three FCCH and then used to collect data in 133 FCCH.
The final three-factor solution (‘coercive control and indulgent feeding practices’, ‘autonomy support practices’, ‘negative role modelling’) captured 43 % of total variance. In multilevel mixed models adjusted for covariates, ‘autonomy support practices’ was positively associated with children’s diet quality. A 1-unit increase in the use of ‘autonomy support practices’ was associated with a 9·4-unit increase in child HEI-2010 score (P=0·001).
Similar to the parenting literature, constructs which describe coercive controlling practices and those which describe autonomy-supportive practices emerged. Given that diets of pre-schoolers in the USA remain suboptimal, teaching childcare providers about supportive feeding practices may help improve children’s diet quality.
This pilot study examined changes in physical activity and function among older adults moving from community dwellings to retirement living. Twelve community-dwelling older adults, recruited from the wait-lists of two retirement living facilities, were assessed prior to and following the transition to retirement living. Physical activity was assessed using an Actigraph (GT3X+) activity monitor; physical activity by type was reported with the CHAMPS activity questionnaire. Physical function was assessed using the Senior Fitness Test. Objectively monitored total physical activity decreased after the transition to retirement living (p = 0.02). Reports of physical activity by type indicated that only activities of daily living decreased (p < 0.01) although intentional exercise increased (p < 0.03) with the transition. Endurance and strength also improved (p < 0.05 and p < 0.04). Pilot results indicate that possible physical benefits accrue from retirement living, although efforts to reduce sedentary time are needed.
Data were pooled from three Australian sentinel general practice influenza surveillance networks to estimate Australia-wide influenza vaccine coverage and effectiveness against community presentations for laboratory-confirmed influenza for the 2012, 2013 and 2014 seasons. Patients presenting with influenza-like illness at participating GP practices were swabbed and tested for influenza. The vaccination odds of patients testing positive were compared with patients testing negative to estimate influenza vaccine effectiveness (VE) by logistic regression, adjusting for age group, week of presentation and network. Pooling of data across Australia increased the sample size for estimation from a minimum of 684 to 3,683 in 2012, from 314 to 2,042 in 2013 and from 497 to 3,074 in 2014. Overall VE was 38% [95% confidence interval (CI) 24–49] in 2012, 60% (95% CI 45–70) in 2013 and 44% (95% CI 31–55) in 2014. For A(H1N1)pdm09 VE was 54% (95% CI–28 to 83) in 2012, 59% (95% CI 33–74) in 2013 and 55% (95% CI 39–67) in 2014. For A(H3N2), VE was 30% (95% CI 14–44) in 2012, 67% (95% CI 39–82) in 2013 and 26% (95% CI 1–45) in 2014. For influenza B, VE was stable across years at 56% (95% CI 37–70) in 2012, 57% (95% CI 30–73) in 2013 and 54% (95% CI 21–73) in 2014. Overall VE against influenza was low in 2012 and 2014 when A(H3N2) was the dominant strain and the vaccine was poorly matched. In contrast, overall VE was higher in 2013 when A(H1N1)pdm09 dominated and the vaccine was a better match. Pooling data can increase the sample available and enable more precise subtype- and age group-specific estimates, but limitations remain.
The direct collapse model of supermassive black hole seed formation requires that the
gas cools predominantly via atomic hydrogen. To this end we simulate the effect of an
anisotropic radiation source on the collapse of a halo at high redshift. The radiation
source is placed at a distance of 3 kpc (physical) from the collapsing object and is set
to emit monochromatically in the center of the Lyman-Werner (LW) band. The LW radiation
emitted from the high redshift source is followed self-consistently using ray tracing
techniques. Due to self-shielding, a small amount of H2 is able to form at the very
center of the collapsing halo even under very strong LW radiation. Furthermore, we find that
a radiation source, emitting < 1054 (∼103 J21) photons per second is
required to cause the collapse of a clump of M ∼ 105 M⊙. The resulting
accretion rate onto the collapsing object is ∼ 0.25 M⊙ yr−1.
Our results display significant differences, compared to the isotropic radiation field case,
in terms of H2 fraction at an equivalent radius. These differences will significantly effect
the dynamics of the collapse. With the inclusion of a strong anisotropic radiation source, the
final mass of the collapsing object is found to be M ∼ 105 M⊙. This is consistent
with predictions for the formation of a supermassive star or quasi-star leading to a
supermassive black hole.