17 research outputs found

    Probing black hole accretion tracks, scaling relations, and radiative efficiencies from stacked X-ray active galactic nuclei

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    The masses of supermassive black holes at the centres of local galaxies appear to be tightly correlated with the mass and velocity dispersions of their galactic hosts. However, the local Mbh–Mstar relation inferred from dynamically measured inactive black holes is up to an order-of-magnitude higher than some estimates from active black holes, and recent work suggests that this discrepancy arises from selection bias on the sample of dynamical black hole mass measurements. In this work, we combine X-ray measurements of the mean black hole accretion luminosity as a function of stellar mass and redshift with empirical models of galaxy stellar mass growth, integrating over time to predict the evolving Mbh–Mstar relation. The implied relation is nearly independent of redshift, indicating that stellar and black hole masses grow, on average, at similar rates. Matching the de-biased local Mbh–Mstar relation requires a mean radiative efficiency ε ≳ 0.15, in line with theoretical expectations for accretion on to spinning black holes. However, matching the ‘raw’ observed relation for inactive black holes requires ε ∼ 0.02, far below theoretical expectations. This result provides independent evidence for selection bias in dynamically estimated black hole masses, a conclusion that is robust to uncertainties in bolometric corrections, obscured active black hole fractions, and kinetic accretion efficiency. For our fiducial assumptions, they favour moderate-to-rapid spins of typical supermassive black holes, to achieve ε ∼ 0.12–0.20. Our approach has similarities to the classic Soltan analysis, but by using galaxy-based data instead of integrated quantities we are able to focus on regimes where observational uncertainties are minimized

    Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

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    Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

    Elections Matter Ten Federal Elections That Shaped Australia

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    In a world of fake news and populist politics, elections can seem like theatre. With growing rates of informal votes and a perceived narrowing of differences between the major parties, do Australian elections really matter? Taking ten examples, this book argues that elections do matter (even when you think they don’t). It is not just elections with memorable jingles or triumphant campaigns from opposition to government that can shape the nation. Could it be that the Labor loss in 1969 formed the country more than the famous win in 1972? Or did the return of the Coalition in 1954 have more impact than securing government in 1949? Elections Matter looks at prime ministers and policies that never were and examines how the democratic process could have produced a different country. Had key elections taken a different turn, Australia might have had a different constitution, a different head of state, a different health and education system and a different foreign policy approach. This book looks at ten elections that formed Australia

    Management of Adult Patients with Cardiac Failure

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    Management of Adult Patients with Cardiac Failur

    Star formation in LINER host galaxies at z~0.3

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    We present the results of a Herschel-PACS study of a sample of 97 LINERs at redshift z\sim 0.3 selected from the zCOSMOS survey. Of these sources, 34 are detected in a least one PACS band, enabling reliable estimates of the far-infrared L(FIR) luminosities, and a comparison to the FIR luminosities of local LINERs. Many of our PACS-detected LINERs are also UV sources detected by Galex. Assuming that the FIR is produced in young dusty star-forming regions, the typical star-formation rates (SFRs) for the host galaxies in our sample is \sim 10 M_Sun yr-1, 1-2 orders of magnitude larger than in many local LINERs. Given stellar masses inferred from optical/NIR photometry of the (unobscured) evolved stellar populations, we find that the entire sample lies close to the star-forming "main sequence" for galaxies at redshift 0.3. For young star-forming regions, the H\alpha- and UV-based estimates of the SFRs are much smaller than the FIR-based estimates, by factors \sim 30, even assuming that all of the H\alpha\ emission is produced by O-star ionization rather than by the AGNs. These discrepancies may be due to large (and uncertain) extinctions towards the young stellar systems. Alternatively, the H\alpha\ and UV emissions could be tracing residual star-formation in an older less obscured population with decaying star formation. We also compare L(SF) and L(AGN) in local LINERs and in our sample and comment on the problematic use of several line diagnostic diagrams in cases similar to the sample under study.Comment: Tommasin et al. 2012, ApJ, 753, 15

    Large Negative Thermal Expansion and Anomalous Behavior on Compression in Cubic ReO<sub>3</sub>‑Type A<sup>II</sup>B<sup>IV</sup>F<sub>6</sub>: CaZrF<sub>6</sub> and CaHfF<sub>6</sub>

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    CaZrF<sub>6</sub> and CaHfF<sub>6</sub> display much stronger negative thermal expansion (NTE) (<i>α</i><sub>L100 K</sub> ∼ −18 and −22 ppm·K<sup>–1</sup>, respectively) than ZrW<sub>2</sub>O<sub>8</sub> and other corner-shared framework structures. Their NTE is comparable to that reported for framework solids containing multiatom bridges, such as metal cyanides and metal–organic frameworks. However, they are formable as ceramics, transparent over a wide wavelength range and can be handled in air; these characteristics can be beneficial for applications. The NTE of CaZrF<sub>6</sub> is strongly temperature-dependent, and first-principles calculations show that it is largely driven by vibrational modes below ∼150 cm<sup>–1</sup>. CaZrF<sub>6</sub> is elastically soft with a bulk modulus (<i>K</i><sub>300K</sub>) of 37 GPa and, upon compression, starts to disorder at ∼400 MPa. The strong NTE of CaZrF<sub>6</sub>, which remains cubic to <10 K, contrasts with cubic CoZrF<sub>6</sub>, which only displays modest NTE above its rhombohedral to cubic phase transition at ∼270 K. CaZrF<sub>6</sub> and CaHfF<sub>6</sub> belong to a large and compositionally diverse family of materials, A<sup>II</sup>B<sup>IV</sup>F<sub>6</sub>, providing for a detailed exploration of the chemical and structural factors controlling NTE and many opportunities for the design of controlled thermal expansion materials
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