Purpose
To describe the change in ventilatory practice in a tertiary paediatric intensive care unit (PICU) in the 5-year period after the introduction of high-flow nasal prong (HFNP) therapy in ...infants <24 months of age. Additionally, to identify the patient subgroups on HFNP requiring escalation of therapy to either other non-invasive or invasive ventilation, and to identify any adverse events associated with HFNP therapy.
Methods
The study was a retrospective chart review of infants <24 months of age admitted to our PICU for HFNP therapy. Data was also extracted from both the local database and the Australian New Zealand paediatric intensive care (ANZPIC) registry for all infants admitted with bronchiolitis.
Results
Between January 2005 and December 2009, a total of 298 infants <24 months of age received HFNP therapy. Overall, 36 infants (12%) required escalation to invasive ventilation. In the subgroup with a primary diagnosis of viral bronchiolitis (
n
= 167, 56%), only 6 (4%) required escalation to invasive ventilation. The rate of intubation in infants with viral bronchiolitis reduced from 37% to 7% over the observation period corresponding with an increase in the use of HFNP therapy. No adverse events were identified with the use of HFNP therapy.
Conclusion
HFNP therapy has dramatically changed ventilatory practice in infants <24 months of age in our institution, and appears to reduce the need for intubation in infants with viral bronchiolitis.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
We report observations of the linear polarization of a sample of 50 nearby Southern bright stars measured to a median sensitivity of ∼4.4 × 10−6. We find larger polarizations and more highly ...polarized stars than in the previous PlanetPol survey of Northern bright stars. This is attributed to a dustier interstellar medium in the mid-plane of the Galaxy, together with a population containing more B-type stars leading to more intrinsically polarized stars, as well as using a wavelength more sensitive to intrinsic polarization in late-type giants. Significant polarization had been identified for only six stars in the survey group previously, whereas we are now able to deduce intrinsic polarigenic mechanisms for more than 20. The four most highly polarized stars in the sample are the four classical Be stars (α Eri, α Col, η Cen and α Ara). For the three of these objects resolved by interferometry, the position angles are consistent with the orientation of the circumstellar disc determined. We find significant intrinsic polarization in most B stars in the sample; amongst these are a number of close binaries and an unusual binary debris disc system. However, these circumstances do not account for the high polarizations of all the B stars in the sample and other polarigenic mechanisms are explored. Intrinsic polarization is also apparent in several late-type giants which can be attributed to either close, hot circumstellar dust or bright spots in the photosphere of these stars. Aside from a handful of notable debris disc systems, the majority of A–K type stars show polarization levels consistent with interstellar polarization.
The German-British laser-interferometric gravitational wave detector GEO 600 is in its 14th year of operation since its first lock in 2001. After GEO 600 participated in science runs with other ...first-generation detectors, a program known as GEO-HF began in 2009. The goal was to improve the detector sensitivity at high frequencies, around 1 kHz and above,with technologically advanced yet minimally invasive upgrades. Simultaneously, the detector would record science quality data in between commissioning activities. As of early 2014, all of the planned upgrades have been carried out and sensitivity improvements of up to a factor of four at the high-frequency end of the observation band have been achieved. Besides science data collection, an experimental program is ongoing with the goal to further improve the sensitivity and evaluate future detector technologies. We summarize the results of the GEO-HF program to date and discuss its successes and challenges.
The ability to measure tiny variations in the local gravitational acceleration allows, besides other applications, the detection of hidden hydrocarbon reserves, magma build-up before volcanic ...eruptions, and subterranean tunnels. Several technologies are available that achieve the sensitivities required for such applications (tens of microgal per hertz(1/2)): free-fall gravimeters, spring-based gravimeters, superconducting gravimeters, and atom interferometers. All of these devices can observe the Earth tides: the elastic deformation of the Earth's crust as a result of tidal forces. This is a universally predictable gravitational signal that requires both high sensitivity and high stability over timescales of several days to measure. All present gravimeters, however, have limitations of high cost (more than 100,000 US dollars) and high mass (more than 8 kilograms). Here we present a microelectromechanical system (MEMS) device with a sensitivity of 40 microgal per hertz(1/2) only a few cubic centimetres in size. We use it to measure the Earth tides, revealing the long-term stability of our instrument compared to any other MEMS device. MEMS accelerometers--found in most smart phones--can be mass-produced remarkably cheaply, but none are stable enough to be called a gravimeter. Our device has thus made the transition from accelerometer to gravimeter. The small size and low cost of this MEMS gravimeter suggests many applications in gravity mapping. For example, it could be mounted on a drone instead of low-flying aircraft for distributed land surveying and exploration, deployed to monitor volcanoes, or built into multi-pixel density-contrast imaging arrays.
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IJS, KISLJ, NUK, SBMB, UL, UM, UPUK
We report observations of the linear polarization of a sample of 49 nearby bright stars measured to sensitivities of between ∼1 and ∼ 4 × 10−6. The majority of stars in the sample show measurable ...polarization, but most polarizations are small with 75 per cent of the stars having P < 2 × 10−5. Correlations of the polarization with distance and position indicate that most of the polarization is of interstellar origin. Polarizations are small near the galactic pole and larger at low-galactic latitudes, and the polarization increases with distance. However, the interstellar polarization is very much less than would be expected based on polarization–distance relations for distant stars showing that the solar neighbourhood has little interstellar dust. BS 3982 (Regulus) has a polarization of ∼ 37 × 10−6, which is most likely due to electron scattering in its rotationally flattened atmosphere. BS 7001 (Vega) has polarization at a level of ∼ 17 × 10−6 which could be due to scattering in its dust disc, but is also consistent with interstellar polarization in this direction. The highest polarization observed is that of BS 7405 (α Vul) with a polarization of 0.13 per cent.
We present the results of a detailed study of interstellar polarization efficiency (as measured by the ratio p lambda / tau lambda ) toward molecular clouds, with the aim of discriminating between ...grain alignment mechanisms in dense regions of the interstellar medium. The data set includes both continuum measurements in the K (2.2 mu m) passband and values based on ice and silicate spectral features. Background field stars are used to probe polarization efficiency in quiescent regions of dark clouds, yielding a dependence on visual extinction well-represented by a power law (p lambda / tau lambda proportional to A sub(v) super(-0.52)), in agreement with previous work. No significant change in this behavior is observed in the transition region between the diffuse outer layers and dense inner regions of clouds, where icy mantles are formed, and we conclude that mantle formation has little or no effect on the efficiency of grain alignment. The field-star data are used as a template for comparison with results for embedded young stellar objects (YSOs). The latter generally exhibit greater polarization efficiency compared with field stars at comparable extinctions, some displaying enhancements in p lambda / tau lambda by factors of up to similar to 6 with respect to the power-law fit. Of the proposed alignment mechanisms, that based on radiative torques appears best able to explain the data. The attenuated external radiation field appears adequate to account for the observed polarization in quiescent regions for extinctions up to A sub(v) similar to 10 mag. Radiation from the embedded stars themselves may enhance alignment in the lines of sight to YSOs. Enhancements in p lambda tau lambda observed in the ice features toward several YSOs are of greatest significance, as they demonstrate efficient alignment in cold molecular clouds associated with star formation.
We describe the HIgh Precision Polarimetric Instrument (HIPPI), a polarimeter built at UNSW (The University of New South Wales) Australia and used on the Anglo-Australian Telescope (AAT). HIPPI is an ...aperture polarimeter using a ferro-electric liquid crystal modulator. HIPPI measures the linear polarization of starlight with a sensitivity in fractional polarization of ~4 x 10... on low-polarization objects and a precision of better than 0.01 per cent on highly polarized stars. The detectors have a high dynamic range allowing observations of the brightest stars in the sky as well as much fainter objects. The telescope polarization of the AAT is found to be 48 plus or minus 5 x 10... in the g' band. (ProQuest: ... denotes formulae/symbols omitted.)
The tree of life of fishes is in a state of flux because we still lack a comprehensive phylogeny that includes all major groups. The situation is most critical for a large clade of spiny-finned ...fishes, traditionally referred to as percomorphs, whose uncertain relationships have plagued ichthyologists for over a century. Most of what we know about the higher-level relationships among fish lineages has been based on morphology, but rapid influx of molecular studies is changing many established systematic concepts. We report a comprehensive molecular phylogeny for bony fishes that includes representatives of all major lineages. DNA sequence data for 21 molecular markers (one mitochondrial and 20 nuclear genes) were collected for 1410 bony fish taxa, plus four tetrapod species and two chondrichthyan outgroups (total 1416 terminals). Bony fish diversity is represented by 1093 genera, 369 families, and all traditionally recognized orders. The maximum likelihood tree provides unprecedented resolution and high bootstrap support for most backbone nodes, defining for the first time a global phylogeny of fishes. The general structure of the tree is in agreement with expectations from previous morphological and molecular studies, but significant new clades arise. Most interestingly, the high degree of uncertainty among percomorphs is now resolved into nine well-supported supraordinal groups. The order Perciformes, considered by many a polyphyletic taxonomic waste basket, is defined for the first time as a monophyletic group in the global phylogeny. A new classification that reflects our phylogenetic hypothesis is proposed to facilitate communication about the newly found structure of the tree of life of fishes. Finally, the molecular phylogeny is calibrated using 60 fossil constraints to produce a comprehensive time tree. The new time-calibrated phylogeny will provide the basis for and stimulate new comparative studies to better understand the evolution of the amazing diversity of fishes.
Thermal noise of highly reflective mirror coatings is a major limit to the sensitivity of many precision laser experiments with strict requirements such as low optical absorption. Here, we ...investigate amorphous silicon and silicon nitride as an alternative to the currently used combination of coating materials, silica, and tantala. We demonstrate an improvement by a factor of ≈55 with respect to the lowest so far reported optical absorption of amorphous silicon at near-infrared wavelengths. This reduction was achieved via a combination of heat treatment, final operation at low temperature, and a wavelength of 2 μm instead of the more commonly used 1550 nm. Our silicon-based coating offers a factor of 12 thermal noise reduction compared to the performance possible with silica and tantala at 20 K. In gravitational-wave detectors, a noise reduction by a factor of 12 corresponds to an increase in the average detection rate by three orders of magnitude (≈12^{3}).
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CMK, CTK, FMFMET, IJS, NUK, PNG, UL, UM
The polarization of HD 189733 Bott, Kimberly; Bailey, Jeremy; Kedziora-Chudczer, Lucyna ...
Monthly notices of the Royal Astronomical Society. Letters,
06/2016, Volume:
459, Issue:
1
Journal Article
Peer reviewed
Open access
We present linear polarization observations of the exoplanet system HD 189733 made with the HIgh Precision Polarimetric Instrument (HIPPI) on the Anglo-Australian Telescope (AAT). The observations ...have higher precision than any previously reported for this object. They do not show the large amplitude polarization variations reported by Berdyugina et al. Our results are consistent with polarization data presented by Wiktorowicz et al. A formal least squares fit of a Rayleigh–Lambert model yields a polarization amplitude of 29.4 ± 15.6 parts per million. We observe a background constant level of polarization of ∼55–70 ppm, which is a little higher than expected for interstellar polarization at the distance of HD 189733.
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