The Great Eruption of Eta Carinae

During the years 1838-1858, the very massive star {\eta} Carinae became the prototype supernova impostor: it released nearly as much light as a supernova explosion and shed an impressive amount of mass, but survived as a star.1 Based on a light-echo spectrum of that event, Rest et al.2 conclude that "a new physical mechanism" is required to explain it, because the gas outflow appears cooler than theoretical expectations. Here we note that (1) theory predicted a substantially lower temperature than they quoted, and (2) their inferred observational value is quite uncertain. Therefore, analyses so far do not reveal any significant contradiction between the observed spectrum and most previous discussions of the Great Eruption and its physics.Comment: To appear in Nature, a brief communication arising in response to Rest et al. 2012. Submitted to Nature February 17, 201

Vector meson spectral function and dilepton rate in an effective mean field model

We have studied the vector meson spectral function (VMSF) in a hot and dense medium within an effective QCD model namely the Nambu-Jona-Lasinio (NJL) and its Polyakov Loop extended version (PNJL) with and without the effect of isoscalar vector interaction (IVI). The effect of the IVI has been taken into account using the ring approximation. We obtained the dilepton production rate (DPR) using the VMSF and observed that at moderate temperature it is enhanced in the PNJL model as compared to the NJL and Born rate due to the suppression of color degrees of freedom.Comment: 5 pages, 7 figures, conference proceedings of the XXI DAE-BRNS HEP Symposium, IIT Guwahati, December 2014; to appear in 'Springer Proceedings in Physics Series

Discussing prognosis and end-of-life care in the final year of life: A randomized controlled trial of a nurse-led ommunication support programme for patients and caregivers

Introduction: Timely communication about lifeexpectancy and end-of-life care is crucial forensuring good patient quality-of-life at the end of lifeand a good quality of death. This article describes theprotocol for a multisite randomised controlled trial of anurse-led communication support programme tofacilitate patients' and caregivers' efforts tocommunicate about these issues with theirhealthcare team.Methods and analysis: This NHMRC-sponsored trialis being conducted at medical oncology clinics locatedat/affiliated with major teaching hospitals in Sydney,Australia. Patients with advanced, incurable cancer andlife expectancy of less than 12 months will participatetogether with their primary informal caregiver wherepossible. Guided by the self-determination theory ofhealth-behaviour change, the communication supportprogramme pairs a purpose-designed Question PromptList (QPL-an evidence-based list of questionspatients/caregivers can ask clinicians) with nurse-ledexploration of QPL content, communication challenges,patient values and concerns and the value of earlydiscussion of end-of-life issues. Oncologists are alsocued to endorse patient and caregiver question askingand use of the QPL. Behavioural and self-report datawill be collected from patients/caregivers approximatelyquarterly for up to 2.5 years or until patient death, afterwhich patient medical records will be examined.Analyses will examine the impact of the intervention onpatients' and caregivers' participation in medicalconsultations, their self-efficacy in medical encounters,quality-of-life, end-of-life care receipt and quality-ofdeathindicators.Ethics and dissemination: Approvals have beengranted by the human ethics review committee ofRoyal Prince Alfred Hospital and governance officersat each participating site. Results will be reported inpeer-reviewed publications and conferencepresentations.Trial registration number: Australian New ZealandClinical Trials Registry ACTRN12610000724077

Light echoes reveal an unexpectedly cool Eta Carinae during its 19th-century Great Eruption

Eta Carinae (Eta Car) is one of the most massive binary stars in the Milky Way. It became the second-brightest star in the sky during its mid-19th century "Great Eruption," but then faded from view (with only naked-eye estimates of brightness). Its eruption is unique among known astronomical transients in that it exceeded the Eddington luminosity limit for 10 years. Because it is only 2.3 kpc away, spatially resolved studies of the nebula have constrained the ejected mass and velocity, indicating that in its 19th century eruption, Eta Car ejected more than 10 M_solar in an event that had 10% of the energy of a typical core-collapse supernova without destroying the star. Here we report the discovery of light echoes of Eta Carinae which appear to be from the 1838-1858 Great Eruption. Spectra of these light echoes show only absorption lines, which are blueshifted by -210 km/s, in good agreement with predicted expansion speeds. The light-echo spectra correlate best with those of G2-G5 supergiant spectra, which have effective temperatures of ~5000 K. In contrast to the class of extragalactic outbursts assumed to be analogs of Eta Car's Great Eruption, the effective temperature of its outburst is significantly cooler than allowed by standard opaque wind models. This indicates that other physical mechanisms like an energetic blast wave may have triggered and influenced the eruption.Comment: Accepted for publication by Nature; 4 pages, 4 figures, SI: 6 pages, 3 figures, 5 table

Short-term outcomes of pubertal suppression in a selected cohort of 12 to 15 year old young people with persistent gender dysphoria in the UK

BACKGROUND: In adolescents with severe and persistent gender dysphoria (GD), gonadotropin releasing hormone analogues (GnRHa) are used from early/middle puberty with the aim of delaying irreversible and unwanted pubertal body changes. Evidence of outcomes of pubertal suppression in GD is limited. METHODS: We undertook an uncontrolled prospective observational study of GnRHa as monotherapy in 44 12-15 year olds with persistent and severe GD. Prespecified analyses were limited to key outcomes: bone mineral content (BMC) and bone mineral density (BMD); Child Behaviour CheckList (CBCL) total t-score; Youth Self-Report (YSR) total t-score; CBCL and YSR self-harm indices; at 12, 24 and 36 months. Semistructured interviews were conducted on GnRHa. RESULTS: 44 patients had data at 12 months follow-up, 24 at 24 months and 14 at 36 months. All had normal karyotype and endocrinology consistent with birth-registered sex. All achieved suppression of gonadotropins by 6 months. At the end of the study one ceased GnRHa and 43 (98%) elected to start cross-sex hormones. There was no change from baseline in spine BMD at 12 months nor in hip BMD at 24 and 36 months, but at 24 months lumbar spine BMC and BMD were higher than at baseline (BMC +6.0 (95% CI: 4.0, 7.9); BMD +0.05 (0.03, 0.07)). There were no changes from baseline to 12 or 24 months in CBCL or YSR total t-scores or for CBCL or YSR self-harm indices, nor for CBCL total t-score or self-harm index at 36 months. Most participants reported positive or a mixture of positive and negative life changes on GnRHa. Anticipated adverse events were common. CONCLUSIONS: Overall patient experience of changes on GnRHa treatment was positive. We identified no changes in psychological function. Changes in BMD were consistent with suppression of growth. Larger and longer-term prospective studies using a range of designs are needed to more fully quantify the benefits and harms of pubertal suppression in GD

Eta Carinae -- Physics of the Inner Ejecta

Eta Carinae's inner ejecta are dominated observationally by the bright Weigelt blobs and their famously rich spectra of nebular emission and absorption lines. They are dense (n_e ~ 10^7 to 10^8 cm^-3), warm (T_e ~ 6000 to 7000 K) and slow moving (~40 km/s) condensations of mostly neutral (H^0) gas. Located within 1000 AU of the central star, they contain heavily CNO-processed material that was ejected from the star about a century ago. Outside the blobs, the inner ejecta include absorption-line clouds with similar conditions, plus emission-line gas that has generally lower densities and a wider range of speeds (reaching a few hundred km/s) compared to the blobs. The blobs appear to contain a negligible amount of dust and have a nearly dust-free view of the central source, but our view across the inner ejecta is severely affected by uncertain amounts of dust having a patchy distribution in the foreground. Emission lines from the inner ejecta are powered by photoionization and fluorescent processes. The variable nature of this emission, occurring in a 5.54 yr event cycle, requires specific changes to the incident flux that hold important clues to the nature of the central object.Comment: This is Chapter 5 in a book entitled: Eta Carinae and the Supernova Impostors, Kris Davidson and Roberta M. Humphreys, editors Springe

Patient perspectives regarding communication about prognosis and end-of-life issues: How can it be optimised?

Objective: To explore patients' perspectives across two cultures (Australia and USA) regarding communication about prognosis and end-of-life care issues and to consider the ways in which these discussions can be optimised. Methods: Fifteen Australian and 11 US patients completed individual semi-structured qualitative interviews. A further 8 US patients participated in a focus group. Interviews and focus group recordings were transcribed verbatim and interpreted using thematic text analysis with an inductive, data-driven approach. Results: Global themes identified included readiness for and outcomes of discussions of prognosis and end-of-life issues. Contributing to readiness were sub themes including patients' adjustment to and acceptance of their condition (together with seven factors promoting this), doctor and patient communication skills, mutual understandings and therapeutic relationship elements. Outcomes included sub themes of achievement of control and ability to move on. A model of the relationships between these factors, emergent cross cultural differences, and how factors may help to optimise these discussions are presented. Conclusion: Identified optimising factors illustrate Australian and US patients' perspectives regarding how prognosis and end-of-life issues can be discussed with minimised negative impact. Practice implications: Recognition of factors promoting adjustment, acceptance and readiness and use of the communication skills and therapeutic relationship elements identified may assist in optimising discussions and help patients plan care, achieve more control of their situation and enjoy an optimal quality-of-life. © 2011 Elsevier Ireland Ltd

Eta Carinae and the Luminous Blue Variables

We evaluate the place of Eta Carinae amongst the class of luminous blue variables (LBVs) and show that the LBV phenomenon is not restricted to extremely luminous objects like Eta Car, but extends luminosities as low as log(L/Lsun) = 5.4 - corresponding to initial masses ~25 Msun, and final masses as low as ~10-15 Msun. We present a census of S Doradus variability, and discuss basic LBV properties, their mass-loss behaviour, and whether at maximum light they form pseudo-photospheres. We argue that those objects that exhibit giant Eta Car-type eruptions are most likely related to the more common type of S Doradus variability. Alternative atmospheric models as well as sub-photospheric models for the instability are presented, but the true nature of the LBV phenomenon remains as yet elusive. We end with a discussion on the evolutionary status of LBVs - highlighting recent indications that some LBVs may be in a direct pre-supernova state, in contradiction to the standard paradigm for massive star evolution.Comment: 27 pages, 6 figures, Review Chapter in "Eta Carinae and the supernova imposters" (eds R. Humphreys and K. Davidson) new version submitted to Springe