Diffuse Thermal X-Ray Emission in the Core of the Young Massive Cluster Westerlund 1

We present an analysis of the diffuse hard X-ray emission in the core of the young massive Galactic cluster Westerlund 1 based on a 48 ks XMM-Newton observation. Chandra results for the diffuse X-ray emission have indicated a soft thermal component together with a hard component that could be either thermal or non-thermal. We seek to resolve this ambiguity regarding the hard component exploiting the higher sensitivity of XMM-Newton to diffuse emission. Our new X-ray spectra from the central (2' radius) diffuse emission are found to exhibit He-like Fe 6.7 keV line emission, demonstrating that the hard emission in the cluster core is predominantly thermal in origin. Potential sources of this hard component are reviewed, namely an unresolved Pre-Main Sequence population, a thermalized cluster wind and Supernova Remnants interacting with stellar winds. We find that the thermalized cluster wind likely contributes the majority of the hard emission with some contribution from the Pre-Main Sequence population. It is unlikely that Supernova Remnants are contributing significantly to the Wd1 diffuse emission at the current epoch

The Physics of Star Cluster Formation and Evolution

© 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00689-4.Star clusters form in dense, hierarchically collapsing gas clouds. Bulk kinetic energy is transformed to turbulence with stars forming from cores fed by filaments. In the most compact regions, stellar feedback is least effective in removing the gas and stars may form very efficiently. These are also the regions where, in high-mass clusters, ejecta from some kind of high-mass stars are effectively captured during the formation phase of some of the low mass stars and effectively channeled into the latter to form multiple populations. Star formation epochs in star clusters are generally set by gas flows that determine the abundance of gas in the cluster. We argue that there is likely only one star formation epoch after which clusters remain essentially clear of gas by cluster winds. Collisional dynamics is important in this phase leading to core collapse, expansion and eventual dispersion of every cluster. We review recent developments in the field with a focus on theoretical work.Peer reviewe

Mid-childhood outcomes of repeat antenatal corticosteroids: a randomized controlled trial

OBJECTIVE: To assess if exposure to repeat dose(s) of antenatal corticosteroids has beneficial abstract effects on neurodevelopment and general health in mid-childhood, at 6 to 8 years’ corrected age. METHODS: Women at risk for very preterm birth, who had received a course of corticosteroids ≥7 days previously, were randomized to intramuscular betamethasone (11.4 mg Celestone Chronodose) or saline placebo, repeated weekly if risk of very preterm birth remained. Midchildhood assessments included neurocognitive function, behavior, growth, lung function, blood pressure, health-related quality of life, and health service utilization. The primary outcome was survival free of neurosensory disability. RESULTS: Of the 1059 eligible long-term survivors, 963 (91%) were included in the primary outcome; 479 (91%) in the repeat corticosteroid group and 484 (91%) in the placebo group. The rate of survival free of neurosensory disability was similar in both groups (78.3% repeat versus 77.3% placebo; risk ratio 1.00, 95% confidence interval, 0.94–1.08). Neurodevelopment, including cognitive function, and behavior, body size, blood pressure, spirometry, and health-related quality of life were similar in both groups, as was the use of health services. CONCLUSIONS: Treatment with repeat dose(s) of antenatal corticosteroids was associated with neither benefit nor harm in mid-childhood. Our finding of long-term safety supports the use of repeat dose(s) of antenatal corticosteroids, in view of the related neonatal benefits. For women at risk for preterm birth before 32 weeks’ gestation, ≥7 days after an initial course of antenatal corticosteroids, clinicians could consider using a single injection of betamethasone, repeated weekly if risk remains.Caroline A. Crowther, Peter J. Anderson, Christopher J.D. McKinlay, Jane E. Harding, J. Ashwood, Ross R. Jeffery S. Robinson, Lex W. Doyl

Development of natural HEMP fibre sheet mould composites (NF- SMC)

Original paper can be found at: http://www.iccm-central.org/ Copyright British Composites Society [Full text of this paper is not available in the UHRA]The use of natural fibres as reinforcement in polymer composites has generated much interest in recent years due to environmental legislation and improvements on natural fibre performance and process-abilities. This research investigated the use of natural hemp fibre as reinforcement for the possibility of producing fibre reinforced Sheet Moulding Compounds (SMC) as an alternative to glass fibres in the industrial applications ranging from building construction, automotive, to aerospace, where a good fire performance and mechanical properties are essential. This work shows that NFSMC achieved equivalent level of fire and mechanical properties that glass fibre SMC (GFSMC) has provided. Its Heat Release Rate (HRR) in the fire reaction tests reached 150 kWm-2 which is better than that of fire retardant GFSMC; tensile strength reached 44 MPa and Yang's modulus in excess of 14 GPa, which are as the same as the high performance polymeric GFSMC. This report was worked on two aspects of the NFSMC: the selections of raw materials, formulation and a suitable manufacturing system; and the material characterisation and functionality.Peer reviewe

Letter to the Editor

This publication does not have an abstract

Boiling water reactor uranium utilization improvement potential

This report documents the results of design and operational simulation studies to assess the potential for reduction of BWR uranium requirements. The impact of the improvements on separative work requirements and other fuel cycle requirements also were evaluated. The emphasis was on analysis of the improvement potential for once-through cycles, although plutonium recycle also was evaluated. The improvement potential was analyzed for several design alternatives including axial and radial natural uranium blankets, low-leakage refueling patterns, initial core enrichment distribution optimization, reinsert of initial core discharge fuel, preplanned end-of-cycle power coastdown and feedwater temperature reduction, increased discharge burnup, high enrichment discharge fuel rod reassembly and reinsert, lattice and fuel bundle design optimization, coolant density spectral shift with flow control, reduced burnable absorber residual, boric acid for cold shutdown, six-month subcycle refueling, and applications of a once-through thorium cycle design and plutonium recycle

A phase-I study of intravenous bryostatin-1 in patients with advanced cancer

Bryostatin 1 is a novel antitumour agent derived from Bugula neritina of the marine phylum Ectoprocta. Nineteen patients with advanced solid tumours were entered into a phase I study to evaluate the toxicity and biological effects of bryostatin 1. Bryostatin 1 was given as a one hour intravenous infusion at the beginning of each 2 week treatment cycle. A maximum of three treatment cycles were given. Doses were escalated in steps from 5 to 65 jig m-2 in successive patient groups. The maximum tolerated dose was 50 fig m2. Myalgia was the dose limiting toxicity and was of WHO grade 3 in all three patients treated at 65 fig m-2. Flu-like symptoms were common but were of maximum WHO grade 2. Hypotension, of maximum WHO grade 1, occurred in six patients treated at doses up to and including 20 jig m 2 and may not have been attributable to treatment with bryostatin 1. Cellulitis and thrombophlebitis occurred at the bryostatin I infusion site of patients treated at all dose levels up to 50 jig m-2, attributable to the 60% ethanol diluent in the bryostatin 1 infusion. Subsequent patients treated at 50 and 65 jig m-2 received treatment with an intravenous normal saline flush and they did not develop these complications. Significant decreases of the platelet count and total leucocyte, neutrophil and lymphocyte counts were seen in the first 24 h after treatment at the dose of 65 jig m2. Immediate decreases in haemoglobin of up to 1.9g dl-' were also noted in patients treated with 65 iLg m2, in the absence of clinical evidence of bleeding or haemodynamic compromise. No effect was observed on the incidence of haemopoietic progenitor cells in the marrow. Some patients' neutrophils demonstrated enhanced superoxide radical formation in response to in vitro stimulation with opsonised zymosan (a bacterial polysaccharide) but in the absence of this additional stimulus, no bryostatin 1 effect was observed. Lymphocyte natural killing activity was decreased 2 h after treatment with bryostatin 1, but the effect was not consistently seen 24 h or 7 days later. With the dose schedule examined no antitumour effects were observed. We recommend that bryostatin 1 is used at a dose of 35 to 50 jg m-2 two weekly in phase II studies in patients with malignancies including lymphoma, leukaemia, melanoma or hypernephroma, for which pre-clinical investigations suggest antitumour activity