64 research outputs found
Cultural considerations at end of life in a geriatric inpatient rehabilitiation setting
Aim: To explore the impact of cultural factors on the provision of end-of-life care in a geriatric inpatient rehabilitation setting.
Background: Australia’s ageing population is now also one of the most culturally diverse. Individuals from culturally and linguistically diverse backgrounds may have specific care needs at the end of life according to various aspects of their culture.
Design: A mixed method approach using a retrospective audit of existing hospital databases, deceased patients’ medical records, and in-depth interviews with clinicians.
Findings: Patients’ and families’ cultural needs were not always recognised or facilitated in end-of-life care, resulting in missed opportunities to tailor care to the individual’s needs. Clinicians identified a lack of awareness of cultural factors, and how these may influence end-of-life care needs. Clinicians expressed a desire for education opportunities to improve their understanding of how to provide patient-specific, culturally sensitive end-of-life care.
Conclusion: The findings highlight that dying in geriatric inpatient rehabilitation settings remains problematic, particularly when issues of cultural diversity further compound end-of-life care provision. There is a need for recognition and acceptance of the potential sensitivities associated with cultural diversity and how it may influence patients’ and families’ needs at the end of life. Health service organisations should prioritise and make explicit the importance of early referral and utilisation of existing support services such as professional interpreters, specialist palliative care and pastoral care personnel in the provision of end-of-life care. Furthermore, health service organisations should consider reviewing end-of-life care policy documents, guidelines and care pathways to ensure there is an emphasis on respecting and honouring cultural diversity at end of life. If use of a dying care pathway for all dying patients was promoted, or possibly mandated, these issues would likely be addressed.
© 2018 Published by Elsevier Ltd on behalf of Australian College of Nursing Ltd
An XMM-Newton observation of the multiple system HD 167971 (O5-8V+O5-8V+(O81)) and the young open cluster NGC6604
We discuss the results of two XMM-Newton observations of the open cluster NGC 6604 obtained in April and September 2002. We concentrate mainly on the multiple system HD 167971 (O5- 8V + O5- 8V + (O8I)). The soft part of the EPIC spectrum of this system is thermal with typical temperatures of about 2 x 106 to 9 x 106 K. The nature ( thermal vs. non-thermal) of the hard part of the spectrum is not unambiguously revealed by our data. If the emission is thermal, the high temperature of the plasma (similar to 2.3 x 10(7) to 4.6 x 10(7) K) would be typical of what should be expected from a wind-wind interaction zone within a long period binary system. This emission could arise from an interaction between the combined winds of the O5- 8V + O5- 8V close binary system and that of the more distant O8I companion. Assuming instead that the hard part of the spectrum is non-thermal, the photon index would be rather steep (similar to 3). Moreover, a marginal variability between our two XMM-Newton pointings could be attributed to an eclipse of the O5 - 8V + O5 - 8V system. The overall X-ray luminosity points to a significant X-ray luminosity excess of about a factor 4 possibly due to colliding winds. Considering HD 167971 along with several recent X-ray and radio observations, we propose that the simultaneous observation of non-thermal radiation in the X-ray (below 10.0 keV) and radio domains appears rather unlikely. Our investigation of our XMM-Newton data of NGC 6604 reveals a rather sparse distribution of X-ray emitters. Including the two bright non-thermal radio emitters HD 168112 and HD 167971, we present a list of 31 X-ray sources along with the results of the cross-correlation with optical and infrared catalogues. A more complete spectral analysis is presented for the brightest X-ray sources. Some of the members of NGC 6604 present some characteristics suggesting they may be pre-main sequence star candidates
Mass loss from inhomogeneous hot star winds II. Constraints from a combined optical/UV study
Mass-loss rates currently in use for hot, massive stars have recently been
seriously questioned, mainly because of the effects of wind clumping. We
investigate the impact of clumping on diagnostic ultraviolet resonance and
optical recombination lines. Optically thick clumps, a non-void interclump
medium, and a non-monotonic velocity field are all accounted for in a single
model. We used 2D and 3D stochastic and radiation-hydrodynamic (RH) wind
models, constructed by assembling 1D snapshots in radially independent slices.
To compute synthetic spectra, we developed and used detailed radiative transfer
codes for both recombination lines (solving the "formal integral") and
resonance lines (using a Monte-Carlo approach). In addition, we propose an
analytic method to model these lines in clumpy winds, which does not rely on
optically thin clumping. Results: Synthetic spectra calculated directly from
current RH wind models of the line-driven instability are unable to in parallel
reproduce strategic optical and ultraviolet lines for the Galactic O-supergiant
LCep. Using our stochastic wind models, we obtain consistent fits essentially
by increasing the clumping in the inner wind. A mass-loss rate is derived that
is approximately two times lower than predicted by the line-driven wind theory,
but much higher than the corresponding rate derived from spectra when assuming
optically thin clumps. Our analytic formulation for line formation is used to
demonstrate the potential impact of optically thick clumping in weak-winded
stars and to confirm recent results that resonance doublets may be used as
tracers of wind structure and optically thick clumping. (Abridged)Comment: 14 pages+1 Appendix, 8 figures, 3 tables. Accepted for publication in
Astronomy and Astrophysics. One reference updated, minor typo in Appendix
correcte
Discovery of an eccentric 30 days period in the supergiant X-ray binary SAX J1818.6-1703 with INTEGRAL
SAX J1818.6-1703 is a flaring transient X-ray source serendipitously
discovered by BeppoSAX in 1998 during an observation of the Galactic centre.
The source was identified as a High-Mass X-ray Binary with an OB SuperGiant
companion. Displaying short and bright flares and an unusually very-low
quiescent level implying intensity dynamical range as large as 1e3-4, the
source was classified as a Supergiant Fast X-ray Transient. The mechanism
triggering the different temporal behaviour observed between the classical
SGXBs and the recently discovered class of SFXTs is still debated. The
discovery of long orbits (>15 d) should help to discriminate between emission
models and bring constraints.
We analysed archival INTEGRAL data on SAX J1818.6-1703. We built short- and
long-term light curves and performed timing analysis in order to study the
temporal behaviour of SAX J1818.6-1703 on different time scales. INTEGRAL
revealed an unusually long orbital period of 30.0+/-0.2 d and an elapsed
accretion phase of ~6 d in the transient SGXB SAX J1818.6-1703. This implies an
elliptical orbit and constraints the possible supergiant spectral type between
B0.5-1I with eccentricities e~0.3-0.4 (for average fundamental parameters of
supergiant stars). During the accretion phase, the source behaved like
classical SGXBs. The huge variations of the observed X-ray flux can be
explained through accretion of macro-clumps formed within the stellar wind. Our
analysis strengthens the model which predicts that SFXTs behave as SGXBs but
with different orbital parameters, thus different temporal behaviour.Comment: 4 pages, 3 figures, A&A Letter in press (subm. 17/10/2008 - accept.
15/11/2008
Low mass loss rates in O-type stars: Spectral signatures of dense clumps in the wind of two Galactic O4 stars
We have analyzed the far-UV spectrum of two Galactic O4 stars, the O4If+
supergiant HD190429A and the O4V((f)) dwarf HD96715, using archival FUSE and
IUE data. We have conducted a quantitative analysis based on the two NLTE model
atmosphere and wind codes, TLUSTY and CMFGEN. We have derived the stellar and
wind parameters and the surface composition of the two stars. The surface of
HD190429A has a composition typical of an evolved O supergiant (N-rich, C and
O-poor), while HD96715 exhibits surface N enhancement similar to the enrichment
found in SMC O dwarfs and attributed to rotationally-induced mixing. We find
that homogeneous wind models could not match the observed profile of O V1371
and require very low phosphorus abundance to fit the P V1118-1128 resonance
lines. However, we are able to match the O V and P V lines using clumped wind
models. We find that N IV1718 is also sensitive to wind clumping. For both
stars, we have calculated clumped wind models that match well all these lines
from different species and that remain consistent with Halpha data. These fits
therefore provide a coherent and thus much stronger evidence of wind clumping
in O stars than earlier claims. We find that the wind of these two stars is
highly clumped, as expressed by very small volume filling factors, namely
f=0.04 for HD190429A and f=0.02 for HD96715. In agreement with our analysis of
SMC stars, clumping starts deep in the wind, just above the sonic point. The
most crucial consequence of our analysis is that the mass loss rates of O stars
need to be revised downward significantly, by a factor of 3 and more.
Accounting for wind clumping is essential when determining the wind properties
of O stars. Our study therefore calls for a fundamental revision in our
understanding of mass loss and of O-type star winds. (abridged)Comment: To appear in Astronomy & Astrophysics; 16 pages; accepted version
after minor revisio
INTEGRAL long-term monitoring of the Supergiant Fast X-ray Transient XTE J1739-302
In the past few years, a new class of High Mass X-Ray Binaries (HMXRB) has
been claimed to exist, the Supergiant Fast X-ray Transients (SFXT). These are
X-ray binary systems with a compact companion orbiting a supergiant star which
show very short and bright outbursts in a series of activity periods
overimposed on longer quiescent periods. Only very recently the first attempts
to model the behaviour of these sources have been published, some of them
within the framework of accretion from clumpy stellar winds.Our goal is to
analyze the properties of XTE J1739-302/IGR J17391-3021 within the context of
the clumpy structure of the supergiant wind. We have used INTEGRAL and RXTE/PCA
observations in order to obtain broad band (1-200 keV) spectra and light curves
of XTE J1739-302 and investigate its X-ray spectrum and temporal variability.
We have found that XTE J1739-302 follows a much more complex behaviour than
expected. Far from presenting a regular variability pattern, XTE J1739-302
shows periods of high, intermediate, and low flaring activity.Comment: 9 pages, 7 figures, accepted for publication in A&
Radio and submillimetre observations of wind structure in zeta Pup
We present radio and submillimetre observations of the O4I(n)f star zeta Pup,
and discuss structure in the outer region of its wind (~ 10-100 R*). The
properties of bremsstrahlung, the dominant emission process at these
wavelengths, make it sensitive to structure and allow us to study how the
amount of structure changes in the wind by comparing the fluxes at different
wavelengths. To look for variability, we acquired 3.6 and 6 cm observations
with the Australia Telescope Compact Array (ATCA). We supplemented these with
archive observations from the NRAO Very Large Array (VLA). We did not find
variability at more than the +- 20 % level. The long integration time does
allow an accurate determination of the fluxes at 3.6 and 6 cm. Converting these
fluxes into a mass loss rate, we find Mdot = 3.5 x 10^{-6} Msun/yr. This value
confirms the significant discrepancy with the mass loss rate derived from the
Halpha profile, making zeta Pup an exception to the usually good agreement
between Halpha and radio mass loss rates. We also observed zeta Pup at 850 mum
with the James Clerk Maxwell Telescope (JCMT) and at 20 cm with the VLA. A
smooth wind model shows that the millimetre fluxes are too high compared to the
radio fluxes. While recombination of helium in the outer wind cannot be
discounted as an explanation, the wealth of evidence for structure strongly
suggests this as the explanation for the discrepancy. Model calculations show
that the structure needs to be present in the inner ~ 70 R* of the wind, but
that it decays significantly, or maybe even disappears, beyond that radius.Comment: 13 pages, 8 figures, to be published in Astronomy and Astrophysic
3-D radiative transfer in clumped hot star winds I. Influence of clumping on the resonance line formation
The true mass-loss rates from massive stars are important for many branches
of astrophysics. For the correct modeling of the resonance lines, which are
among the key diagnostics of stellar mass-loss, the stellar wind clumping
turned out to be very important. In order to incorporate clumping into
radiative transfer calculation, 3-D models are required. Various properties of
the clumps may have strong impact on the resonance line formation and,
therefore, on the determination of empirical mass-loss rates. We incorporate
the 3-D nature of the stellar wind clumping into radiative transfer
calculations and investigate how different model parameters influence the
resonance line formation. We develop a full 3-D Monte Carlo radiative transfer
code for inhomogeneous expanding stellar winds. The number density of clumps
follows the mass conservation. For the first time, realistic 3-D models that
describe the dense as well as the tenuous wind components are used to model the
formation of resonance lines in a clumped stellar wind. At the same time,
non-monotonic velocity fields are accounted for. The 3-D density and velocity
wind inhomogeneities show very strong impact on the resonance line formation.
The different parameters describing the clumping and the velocity field results
in different line strengths and profiles. We present a set of representative
models for various sets of model parameters and investigate how the resonance
lines are affected. Our 3-D models show that the line opacity is reduced for
larger clump separation and for more shallow velocity gradients within the
clumps. Our new model demonstrates that to obtain empirically correct mass-loss
rates from the UV resonance lines, the wind clumping and its 3-D nature must be
taken into account.Comment: Astronomy and Astrophysics, accepted for publicatio
Modelling the clumping-induced polarimetric variability of hot star winds
Clumping in the winds of massive stars may significantly reduce empirical
mass-loss rates, and which in turn may have a large impact on our understanding
of massive star evolution. Here, we investigate wind-clumping through the
linear polarization induced by light scattering off the clumps. Through the use
of an analytic wind clumping model, we predict the time evolution of the linear
polarimetry over a large parameter space. We concentrate on the Luminous Blue
Variables, which display the greatest amount of polarimetric variability and
for which we recently conducted a spectropolarimetric survey. Our model results
indicate that the observed level of polarimetric variability can be reproduced
for two regimes of parameter space: one of a small number of massive,
optically-thick clumps; and one of a very large number of low-mass clumps.
Although a systematic time-resolved monitoring campaign is required to
distinguish between the two scenarios, we currently favour the latter, given
the short timescale of the observed polarization variability. As the
polarization is predicted to scale linearly with mass-loss rate, we anticipate
that all hot stars with very large mass-loss rates should display polarimetric
variability. This is consistent with recent findings that intrinsic
polarization is more common in stars with strong H emission.Comment: 12 pages, 11 figures, accepted to A&
The conspicuous absence of X-ray emission from carbon-enriched Wolf-Rayet stars
The carbon-rich WC5 star WR 114 was not detected during a 15.9 ksec XMM-Newton observation, implying an upper limit to the X- ray luminosity of L-X less than or similar to 2.5 x 10(30) erg s(-1) and to the X-ray to bolometric luminosity ratio of L- X/L(bo)l less than or similar to 4 x 10(-9). This confirms indications from earlier less sensitive measurements that there has been no convincing X-ray detection of any single WC star. This lack of detections is reinforced by XMM-Newton and Chandra observations of WC stars. Thus the conclusion has to be drawn that the stars with radiatively-driven stellar winds of this particular class are insignificant X-ray sources. We attribute this to photoelectronic absorption by the stellar wind. The high opacity of the metal-rich and dense winds from WC stars puts the radius of optical depth unity at hundreds or thousands of stellar radii for much of the X-ray band. We believe that the essential absence of hot plasma so far out in the wind exacerbated by the large distances and correspondingly high ISM column densities makes the WC stars too faint to be detectable with current technology. The result also applies to many WC stars in binary systems, of which only about 20% are identified X-ray sources, presumably due to colliding winds
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