4,982 research outputs found
History of screening by BreastScreen New South Wales of women with invasive breast cancer
© 2019 The Author(s) Background: The principal target age for Australian BreastScreen services was 50–69 years in 1991–2013 and 50–74 years from 2014. History of BreastScreen NSW screening participation of NSW women diagnosed with breast cancer in 2005–2014 was examined using linked BreastScreen and Cancer Registry data. Methods: Differences in BreastScreen participation were investigated by sociodemographic and tumour characteristics, and diagnostic period, using the Pearson Chi-square test, or Fisher's Exact test when numbers were small, and by multivariate logistic regression. Results: At breast cancer diagnosis, a history of BreastScreen participation varied by age from 23 % for 40−49 years to 68 % for 50–59 years, 72 % for 70–74 years and 78 % for 60–69 years. Among women experiencing breast cancer at age 50–69 years, 60 % had participated in BreastScreen <24 months of diagnosis. Higher odds of BreastScreen participation applied to residents of inner regional and remote compared with major city areas and for women with localized compared with more distant cancer spread. BreastScreen participation was lower in Indigenous than non-Indigenous women. Differences in participation existed by country of birth and residential location, but they were not pronounced. Conclusion: The history of BreastScreen NSW participation of 60 % <24 months for women aged 50–69 years at breast-cancer diagnosis is less than the 70 % target for biennial screening coverage at a population level, but this target has never been reached by an Australian jurisdiction. Qualitative research of screening barriers and opportunities may provide a useful guide for reducing barriers across the population
Room-temperature exciton-polaritons with two-dimensional WS2
Two-dimensional transition metal dichalcogenides exhibit strong optical
transitions with significant potential for optoelectronic devices. In
particular they are suited for cavity quantum electrodynamics in which strong
coupling leads to polariton formation as a root to realisation of inversionless
lasing, polariton condensationand superfluidity. Demonstrations of such
strongly correlated phenomena to date have often relied on cryogenic
temperatures, high excitation densities and were frequently impaired by strong
material disorder. At room-temperature, experiments approaching the strong
coupling regime with transition metal dichalcogenides have been reported, but
well resolved exciton-polaritons have yet to be achieved. Here we report a
study of monolayer WS coupled to an open Fabry-Perot cavity at
room-temperature, in which polariton eigenstates are unambiguously displayed.
In-situ tunability of the cavity length results in a maximal Rabi splitting of
meV, exceeding the exciton linewidth. Our data
are well described by a transfer matrix model appropriate for the large
linewidth regime. This work provides a platform towards observing strongly
correlated polariton phenomena in compact photonic devices for ambient
temperature applications.Comment: 12 pages, 6 figure
V2051 Ophiuchi after superoutburst : out-of-plane material and the superhump light source
Aims. We performed a detailed spectroscopic analysis of the dwarf nova V2051 Oph at the end of its 1999 superoutburst. We studied and interpreted the simultaneous behaviour of various emission lines.
Methods. We obtained high-resolution echelle spectroscopic data at ESO’s NTT with EMMI, covering the spectral range of 4000–7500 Å. The analysis was performed using standard IRAF tools. The indirect imaging technique of Doppler tomography was applied, in order to map the accretion disc and distinguish between the different emission sources.
Results. The spectra are characterised by strong Balmer emission, together with lines of He i and the iron triplet Fe ii 42. All lines are double-peaked, but the blue-to-red peak strength and central absorption depth vary. The primary’s velocity was found to be 84.9 kms−1. The spectrograms of the emission lines reveal the prograde rotation of a disc-like emitting region and, for the Balmer and He i lines, an enhancement of the red-wing during eclipse indicates a bright spot origin. The modulation of the double-peak separation shows a highly asymmetric disc with non-uniform emissivity. This is confirmed by the Doppler maps, which apart from the disc and bright spot emission also indicate an additional region of enhanced emission in the 4th quadrant (+Vx, −Vy), which we associate with the superhump light source. Given the behaviour of the iron triplet and its distinct differences from the rest of the lines, we attribute its existence to an extended gas region above the disc. Its origin can be explained through the fluorescence mechanism
Flight evaluation of advanced flight control systems and cockpit displays for powered-lift STOL Aircraft
A flight research program was conducted to assess the improvements, in longitudinal path control during a STOL approach and landing, that can be achieved with manual and automatic control system concepts and cockpit displays with various degrees of complexity. NASA-Ames powered-lift Augmentor Wing Research Aircraft was used in the research program. Satisfactory flying qualities were demonstrated for selected stabilization and command augmentation systems and flight director combinations. The ability of the pilot to perform precise landings at low touchdown sink rates with a gentle flare maneuver was also achieved. The path-control improvement is considered to be applicable to other powered-lift aircraft configurations
Spectroscopy of Seven Cataclysmic Variables with Periods Above Five Hours
We present spectroscopy of seven cataclysmic variable stars with orbital
periods P(orb) greater than 5 hours, all but one of which are known to be dwarf
novae. Using radial velocity measurements we improve on previous orbital period
determinations, or derive periods for the first time. The stars and their
periods are
TT Crt, 0.2683522(5) d;
EZ Del, 0.2234(5) d;
LL Lyr, 0.249069(4) d;
UY Pup, 0.479269(7) d;
RY Ser, 0.3009(4) d;
CH UMa, 0.3431843(6) d; and
SDSS J081321+452809, 0.2890(4) d.
For each of the systems we detect the spectrum of the secondary star,
estimate its spectral type, and derive a distance based on the surface
brightness and Roche lobe constraints. In five systems we also measure the
radial velocity curve of the secondary star, estimate orbital inclinations, and
where possible estimate distances based on the MV(max) vs.P(orb) relation found
by Warner. In concordance with previous studies, we find that all the secondary
stars have, to varying degrees, cooler spectral types than would be expected if
they were on the main sequence at the measured orbital period.Comment: 25 pages, 2 figures, accepted for Publications of the Astronomical
Society of the Pacifi
The masses of the cataclysmic variables AC Cancri and V363 Aurigae
We present time-resolved spectroscopy and photometry of the double-lined eclipsing cataclysmic variables AC Cnc and V363 Aur (= Lanning 10). There is evidence of irradiation on the inner hemisphere of the secondary star in both systems, which we correct for using a model that reproduces the observations remarkably well. We find the radial velocity of the secondary star in AC Cnc to be KR= 176 ± 3 km s−1 and its rotational velocity to be v sin i= 135 ± 3 km s−1. From these parameters we obtain masses of M1= 0.76 ± 0.03 M⊙ for the white-dwarf primary and M2= 0.77 ± 0.05 M⊙ for the K2 ± 1V secondary star, giving a mass ratio of q= 1.02 ± 0.04. We measure the radial and rotational velocities of the G7 ± 2V secondary star in V363 Aur to be KR= 168 ± 5 km s−1 and v sin i= 143 ± 5 km s−1, respectively. The component masses of V363 Aur are M1= 0.90 ± 0.06 M⊙ and M2= 1.06 ± 0.11 M⊙, giving a mass ratio of q= 1.17 ± 0.07. The mass ratios for AC Cnc and V363 Aur fall within the theoretical limits for dynamically and thermally stable mass transfer. Both systems are similar to the SW Sex stars, exhibiting single-peaked emission lines with transient absorption features, high-velocity S-wave components and phase-offsets in their radial-velocity curves. The Balmer lines in V363 Aur show a rapid increase in flux around phase 0 followed by a rapid decrease, which we attribute to the eclipse of an optically thick region at the centre of the disc. This model could also account for the behaviour of other SW Sex stars where the Balmer lines show only a shallow eclipse compared to the continuum
An Accurate Determination of the Optical Periodic Modulation in the X-Ray Binary SAX J1808.4-3658
We report on optical imaging of the X-ray binary SAX J1808.4-3658 with the
8-m Gemini South Telescope. The binary, containing an accretion-powered
millisecond pulsar, appears to have a large periodic modulation in its
quiescent optical emission. In order to clarify the origin of this modulation,
we obtained three time-resolved -band light curves (LCs) of the source in
five days. The LCs can be described by a sinusoid, and the long time-span
between them allows us to determine optical period P=7251.9 s and phase 0.671
at MJD 54599.0 (TDB; phase 0.0 corresponds to the ascending node of the pulsar
orbit), with uncertainties of 2.8 s and 0.008 (90 % confidence), respectively.
This periodicity is highly consistent with the X-ray orbital ephemeris. By
considering this consistency and the sinusoidal shape of the LCs, we rule out
the possibility of the modulation arising from the accretion disk. Our study
supports the previous suggestion that the X-ray pulsar becomes rotationally
powered in quiescence, with its energy output irradiating the companion star,
causing the optical modulation. While it has also been suggested that the
accretion disk would be evaporated by the pulsar, we argue that the disk exists
and gives rise to the persistent optical emission. The existence of the disk
can be verified by long-term, multi-wavelength optical monitoring of the source
in quiescence, as an increasing flux and spectral changes from the source would
be expected based on the standard disk instability model.Comment: 7 pages, 3 figures. Accepted for publication in Ap
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