13 research outputs found

    Recurrent dust formation by WR 48a on a 30-year timescale

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    We present infrared photometry of the WC8 Wolf-Rayet system WR 48a observed with telescopes at ESO, the SAAO and the AAT between 1982 and 2011 which show a slow decline in dust emission from the previously reported outburst in 1978--79 until about 1997, when significant dust emission was still evident. This was followed by a slow rise, accelerating to reach and overtake the first (1978) photometry, demonstrating that the outburst observed in 1978--79 was not an isolated event, but that they recur at intervals of 32+ years. This suggests that WR 48a is a long-period dust maker and colliding-wind binary (CWB). The locus of WR 48a in the (H-L), K colour-magnitude diagram implies that the rate of dust formation fell between 1979 and about 1997 and then increased steadily until 2011. Superimposed on the long-term variation are secondary (`mini') eruptions in (at least) 1990, 1994, 1997, 1999 and 2004, characteristic of relatively brief episodes of additional dust formation. Spectra show evidence for an Oe or Be companion to the WC8 star, supporting the suggestion that WR 48a is a binary system and indicating a system luminosity consistent with the association of WR 48a and the young star clusters Danks 1 and Danks 2. The range of dust formation suggests that these stars are in an elliptical orbit having e ~ 0.6. The size of the orbit implied by the minimum period, together with the WC wind velocity and likely mass-loss rate, implies that the post-shock WC wind is adiabatic throughout the orbit -- at odds with the observed dust formation. A similar conflict is observed in the `pinwheel' dust-maker WR 112.Comment: 15 pages, 8 figures, accepted for publication in MNRA

    Home medicines reviews following acute coronary syndrome: study protocol for a randomized controlled trial

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    Background: Despite continual improvements in the management of acute coronary syndromes, adherence to guideline-based medications remains suboptimal. We aim to improve adherence with guideline-based therapy following acute coronary syndrome using an existing service that is provided by specifically trained pharmacists, called a Home Medicines Review. We have made two minor adjustments to target the focus of the existing service including an acute coronary syndrome specific referral letter and a training package for the pharmacists providing the service.Methods/Design: We will be conducting a randomized controlled trial to compare the directed home medicines review service to usual care following acute coronary syndromes. All patients aged 18 to 80 years and with a working diagnosis of acute coronary syndrome, who are admitted to two public, acute care hospitals, will be screened for enrolment into the trial. Exclusion criteria will include: not being discharged home, documented cognitive decline, non-Medicare eligibility, and presence of a terminal malignancy. Randomization concealment and sequence generation will occur through a centrally-monitored computer program. Patients randomized to the control group will receive usual post-discharge care. Patients randomized to receive the intervention will be offered usual post-discharge care and a directed home medicines review at two months post-discharge. The study endpoints will be six and twelve months post-discharge. The primary outcome will be the proportion of patients who are adherent to a complete, guideline-based medication regimen. Secondary outcomes will include hospital readmission rates, length of hospital stays, changes in quality of life, smoking cessation rates, cardiac rehabilitation completion rates, and mortality.Discussion: As the trial is closely based on an existing service, any improvements observed should be highly translatable into regular practice. Possible limitations to the success of the trial intervention include general practitioner approval of the intervention, general practitioner acceptance of pharmacists' recommendations, and pharmacists' ability to make appropriate recommendations. A detailed monitoring process will detect any barriers to the success of the trial. Given that poor medication persistence following acute coronary syndrome is a worldwide problem, the findings of our study may have international implications for the care of this patient group.Trial registration: Australian New Zealand Clinical Trials Registry ACTRN12611000452998. © 2012 Bernal et al; licensee BioMed Central Ltd

    CT coronary angiography in patients with suspected angina due to coronary heart disease (SCOT-HEART): an open-label,parallel-group, multicentre trial

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    Background The benefi t of CT coronary angiography (CTCA) in patients presenting with stable chest pain has not been systematically studied. We aimed to assess the eff ect of CTCA on the diagnosis, management, and outcome of patients referred to the cardiology clinic with suspected angina due to coronary heart disease. Methods In this prospective open-label, parallel-group, multicentre trial, we recruited patients aged 18–75 years referred for the assessment of suspected angina due to coronary heart disease from 12 cardiology chest pain clinics across Scotland. We randomly assigned (1:1) participants to standard care plus CTCA or standard care alone. Randomisation was done with a web-based service to ensure allocation concealment. The primary endpoint was certainty of the diagnosis of angina secondary to coronary heart disease at 6 weeks. All analyses were intention to treat, and patients were analysed in the group they were allocated to, irrespective of compliance with scanning. This study is registered with ClinicalTrials.gov, number NCT01149590. Findings Between Nov 18, 2010, and Sept 24, 2014, we randomly assigned 4146 (42%) of 9849 patients who had been referred for assessment of suspected angina due to coronary heart disease. 47% of participants had a baseline clinic diagnosis of coronary heart disease and 36% had angina due to coronary heart disease. At 6 weeks, CTCA reclassifi ed the diagnosis of coronary heart disease in 558 (27%) patients and the diagnosis of angina due to coronary heart disease in 481 (23%) patients (standard care 22 [1%] and 23 [1%]; p<0·0001). Although both the certainty (relative risk [RR] 2·56, 95% CI 2·33–2·79; p<0·0001) and frequency of coronary heart disease increased (1·09, 1·02–1·17; p=0·0172), the certainty increased (1·79, 1·62–1·96; p<0·0001) and frequency seemed to decrease (0·93, 0·85–1·02; p=0·1289) for the diagnosis of angina due to coronary heart disease. This changed planned investigations (15% vs 1%; p<0·0001) and treatments (23% vs 5%; p<0·0001) but did not aff ect 6-week symptom severity or subsequent admittances to hospital for chest pain. After 1·7 years, CTCA was associated with a 38% reduction in fatal and nonfatal myocardial infarction (26 vs 42, HR 0·62, 95% CI 0·38–1·01; p=0·0527), but this was not signifi cant. Interpretation In patients with suspected angina due to coronary heart disease, CTCA clarifi es the diagnosis, enables targeting of interventions, and might reduce the future risk of myocardial infarction. Funding The Chief Scientist Offi ce of the Scottish Government Health and Social Care Directorates funded the trial with supplementary awards from Edinburgh and Lothian’s Health Foundation Trust and the Heart Diseases Research Fund

    Introduction. Daughters of time: The shifting identities of contemporary midwives

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    1980 Selected Bibliography

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