A Census of the Carina Nebula -- II. Energy Budget and Global Properties of the Nebulosity

The first paper in this series took a direct census of energy input from the known OB stars in the Carina Nebula, and in this paper we study the global properties of the surrounding nebulosity. We find that the total IR luminosity of Carina is about 1.2E7 Lsun, accounting for only about 50-60% of the known stellar luminosity from Paper I. Similarly, the ionizing photon luminosity -- (abridged; many important details omitted). Synchronized star formation around the periphery of Carina provides a strong case that star formation here was indeed triggered by stellar winds and UV radiation. This second generation appears to involve a cascade toward preferentially intermediate- and low-mass stars, but this may soon change when eta Car and its siblings explode. If the current reservoir of atomic and molecular gas can be tapped at that time, massive star formation may be rejuvinated around the periphery of Carina much as if it were a young version of Gould's Belt. Also, when these multiple SNe occur, the triggered second generation will be pelted repeatedly with SN ejecta bearing short-lived radioactive nuclides. Carina may therefore represent the most observable analog to the cradle of our own Solar System.Comment: MNRAS accepted, 14 pages, fig 1 in colo

Dynamic response and stability of a composite prop-fan model

Results are presented for blade response and stability during wind tunnel tests of a 62.2 cm diameter model of a prop-fan, advanced turboprop, with swept graphite/epoxy composite blades. Measurements of dynamic response were made with the rotor mounted on an isolated nacelle, with varying tilt for nonuniform inflow, at flow speeds from 0.36 to 0.9 Mach number. The blade displayed no instabilities over the operating range tested, up to 0.9 Mach number and 10,000 RPM. Measurements are compared with those for other prop-fan models of both solid metal and graphite composite construction. The swept composite blade had less response than an unswept composite blade. Composite blades had more response than metal blades. Measurements are compared with theoretically based predictions. The 1-P blade response was significantly overpredicted using unimproved methods and somewhat overpredicted using improved methods. Unexpectedly high 2-P strain levels were measured and suggest the presence of nonlinear effects on blade response

Dynamic response of two composite prop-fan models on a nacelle/wing/fuselage half model

Results are presented for blade response wind tunnel tests of two 62.2 cm diameter Prop-Fan (advanced turboprop) models with swept and unswept graphite/epoxy composite blades. Measurements of dynamic response were made with the rotors mounted on a simulated nacelle/wing/fuselage model, with varying tilt, at flow speeds up to 0.85 Mach number. The presence of the wing, downstream of the rotor, induced 1-P responses that were about twice those previously measured for an isolated nacelle installation. The swept blade had less 1-P response than the unswept (straight) blade. The 2-P response was significant for both blades, and was closely correlated to wing lift. Higher order response was not important for the straight blade, but possibly important for the swept blade near critical speeds, due to the proximity of the blade tips to the wing leading edge. Measurements are compared with theoretically based prediction. Correlations between calculated and measured 1-P response were good for the straight blade, and fair for the swept blade. Improvements to the calculation method were identified and implemented

Henri Temianka Correspondence; (bsmith)

https://digitalcommons.chapman.edu/temianka_correspondence/2789/thumbnail.jp

Henri Temianka Correspondence; (bsmith)

https://digitalcommons.chapman.edu/temianka_correspondence/2788/thumbnail.jp

An analysis and visualization of the output mode-matching requirements for squeezing in Advanced LIGO and future gravitational wave detectors

The sensitivity of ground-based gravitational wave (GW) detectors will be improved in the future via the injection of frequency-dependent squeezed vacuum. The achievable improvement is ultimately limited by losses of the interferometer electromagnetic field that carries the GW signal. The analysis and reduction of optical loss in the GW signal chain will be critical for optimal squeezed light-enhanced interferometry. In this work we analyze a strategy for reducing output-side losses due to spatial mode mismatch between optical cavities with the use of adaptive optics. Our goal is not to design a detector from the top down, but rather to minimize losses within the current design. Accordingly, we consider actuation on optics already present and one transmissive optic to be added between the signal recycling mirror and the output mode cleaner. The results of our calculation show that adaptive mode-matching with the current Advanced LIGO design is a suitable strategy for loss reduction that provides less than 2% mean output mode-matching loss. The range of actuation required is +47 uD on SR3, +140 mD on OM1 and OM2, +50 mD on the SRM substrate, and -50 mD on the added new transmissive optic. These requirements are within the demonstrated ranges of real actuators in similar or identical configurations to the proposed implementation. We also present a novel technique that graphically illustrates the matching of interferometer modes and allows for a quantitative comparison of different combinations of actuators.Comment: Matches version accepted in PR

Sepsis caused by bloodstream infection in patients in the intensive care unit: the impact of inactive empiric antimicrobial therapy on outcome

Background: Sepsis is one of the leading causes of death in the UK. Aims: The aims of this study were to identify the rate of inactive antimicrobial therapy (AMT) in the ICU and whether inactive AMT had an effect on in hospital mortality, ICU mortality, 90-day mortality and length of hospital stay. Additionally, we wanted to identify risk factors for receiving inactive AMT. Methods: This was a retrospective observational study conducted at Glasgow Royal Infirmary ICU between January 2010 and December 2013, with 12,000 blood cultures taken over this time period, of which n=127 were deemed clinically significant. Multivariate logistic regression was used to identify risk factors independently associated with mortality. To identify risk factors for receiving inactive AMT a univariable and a subsequent multivariate analysis was constructed. Results: The rate of inactive AMT was 47% (n =60). Our multivariate analysis showed that receiving antibiotics within the first 24 hours of ICU admission led to a reduced mortality (RR 1.70; 95% CI 1.19-2.44.) Furthermore, it showed that severity of illness (as defined by SIRS criteria sepsis vs septic shock) increased mortality (OR 9.87; 95% CI 1.73-55.5). However, inactive AMT did not increase mortality (OR 1.07; 95% CI 0.47-2.41) or length of hospital stay (53.2 vs 69.1 days p=0.348.) We identified fungal bloodstream infection as a risk factor for receiving inactive AMT (OR 5.10;95% CI 1.29-20.14. Conclusion: Mortality from sepsis is influenced by multiple factors. We were unable to demonstrates that inactive AMT had an effect on mortality in sepsis

Mortality in intensive care: The impact of bacteremia and the utility of systemic inflammatory response syndrome

Background: The purpose of this study was to determine the impact of bacteremia on intensive care unit (ICU) mortality and to develop a bacteremia prediction tool using systemic inflammatory response syndrome (SIRS) criteria. Methods: Patients included those aged >18 years who had blood cultures taken in the ICU from January 1, 2011-December 31, 2013. Eligible patients were identified from microbiology records of the Glasgow Royal Infirmary, Scotland. Clinical and outcome data were gathered from ICU records. Patients with clinically significant bacteremia were matched to controls using propensity scores. SIRS criteria were gathered and used to create decision rules to predict the absence of bacteremia. The main outcome was mortality at ICU discharge. The utility of the decision tools was measured using sensitivity and specificity. Results: One hundred patients had a clinically significant positive blood culture and were matched to 100 controls. Patients with bacteremia had higher ICU mortality (odds ratio [OR], 2.35; P = .001) and longer ICU stay (OR, 17.0 vs 7.8 days; P ≤ .001). Of 1,548 blood culture episodes, 1,274 met ≥2 SIRS criteria (106 significant positive cultures and 1,168 negative cultures). There was no association between SIRS criteria and positive blood cultures (P = .11). A decision rule using 3 SIRS criteria had optimal predictive performance (sensitivity, 56%; specificity, 50%) but low accuracy. Conclusions: ICU patients with bacteremia have increased mortality and length of ICU stay. SIRS criteria cannot be used to identify patients at low risk of bacteremia