Formation of the first three gravitational-wave observations through isolated binary evolution

During its first 4 months of taking data, Advanced LIGO has detected gravitational waves from two binary black hole mergers, GW150914 and GW151226, along with the statistically less significant binary black hole merger candidate LVT151012. We use our rapid binary population synthesis code COMPAS to show that all three events can be explained by a single evolutionary channel -- classical isolated binary evolution via mass transfer including a common envelope phase. We show all three events could have formed in low-metallicity environments (Z = 0.001) from progenitor binaries with typical total masses $\gtrsim 160 M_\odot$, $\gtrsim 60 M_\odot$ and $\gtrsim 90 M_\odot$, for GW150914, GW151226, and LVT151012, respectively.Comment: Published in Nature Communication

Accuracy of inference on the physics of binary evolution from gravitational-wave observations

The properties of the population of merging binary black holes encode some of the uncertain physics of the evolution of massive stars in binaries. The binary black hole merger rate and chirp mass distribution are being measured by ground-based gravitational-wave detectors. We consider isolated binary evolution and explore how accurately the physical model can be constrained with such observations by applying the Fisher information matrix to the merging black hole population simulated with the rapid binary population synthesis code COMPAS. We investigate variations in four COMPAS parameters: common envelope efficiency, kick velocity dispersion, and mass loss rates during the luminous blue variable and Wolf--Rayet stellar evolutionary phases. We find that 1000 observations would constrain these model parameters to a fractional accuracy of a few percent. Given the empirically determined binary black hole merger rate, we can expect gravitational-wave observations alone to place strong constraints on the physics of stellar and binary evolution within a few years.Comment: 12 pages, 9 figures; version accepted by Monthly Notices of the Royal Astronomical Societ

STROOPWAFEL: Simulating rare outcomes from astrophysical populations, with application to gravitational-wave sources

Gravitational-wave observations of double compact object (DCO) mergers are providing new insights into the physics of massive stars and the evolution of binary systems. Making the most of expected near-future observations for understanding stellar physics will rely on comparisons with binary population synthesis models. However, the vast majority of simulated binaries never produce DCOs, which makes calculating such populations computationally inefficient. We present an importance sampling algorithm, STROOPWAFEL, that improves the computational efficiency of population studies of rare events, by focusing the simulation around regions of the initial parameter space found to produce outputs of interest. We implement the algorithm in the binary population synthesis code COMPAS, and compare the efficiency of our implementation to the standard method of Monte Carlo sampling from the birth probability distributions. STROOPWAFEL finds $\sim$25-200 times more DCO mergers than the standard sampling method with the same simulation size, and so speeds up simulations by up to two orders of magnitude. Finding more DCO mergers automatically maps the parameter space with far higher resolution than when using the traditional sampling. This increase in efficiency also leads to a decrease of a factor $\sim$3-10 in statistical sampling uncertainty for the predictions from the simulations. This is particularly notable for the distribution functions of observable quantities such as the black hole and neutron star chirp mass distribution, including in the tails of the distribution functions where predictions using standard sampling can be dominated by sampling noise.Comment: Accepted. Data and scripts to reproduce main results is publicly available. The code for the STROOPWAFEL algorithm will be made publicly available. Early inquiries can be addressed to the lead autho

Analysis of Fcγ receptor haplotypes in rheumatoid arthritis: FCGR3A remains a major susceptibility gene at this locus, with an additional contribution from FCGR3B

The Fcγ receptors play important roles in the initiation and regulation of many immunological and inflammatory processes, and genetic variants (FCGR) have been associated with numerous autoimmune and infectious diseases. The data in rheumatoid arthritis (RA) are conflicting and we previously demonstrated an association between FCGR3A and RA. In view of the close molecular proximity with FCGR2A, FCGR2B and FCGR3B, additional polymorphisms within these genes and FCGR haplotypes were examined to refine the extent of association with RA. Biallelic polymorphisms in FCGR2A, FCGR2B and FCGR3B were examined for association with RA in two well characterized UK Caucasian and North Indian/Pakistani cohorts, in which FCGR3A genotyping had previously been undertaken. Haplotype frequencies and linkage disequilibrium were estimated across the FCGR locus and a model-free analysis was performed to determine association with RA. This was followed by regression analysis, allowing for phase uncertainty, to identify the particular haplotype(s) that influences disease risk. Our results reveal that FCGR2A, FCGR2B and FCGR3B were not associated with RA. The haplotype with the strongest association with RA susceptibility was the FCGR3A–FCGR3B 158V-NA2 haplotype (odds ratio 3.18, 95% confidence interval 1.13–8.92 [P = 0.03] for homozygotes compared with all genotypes). The association was stronger in the presence of nodules (odds ratio 5.03, 95% confidence interval 1.44–17.56; P = 0.01). This haplotype was also more common in North Indian/Pakistani RA patients than in control individuals, but not significantly so. Logistic regression analyses suggested that FCGR3A remained the most significant gene at this locus. The increased association with an FCGR3A–FCGR3B haplotype suggests that other polymorphic variants within FCGR3A or FCGR3B, or in linkage disequilibrium with this haplotype, may additionally contribute to disease pathogenesis

Association of FCGR2A and FCGR2A-FCGR3A haplotypes with susceptibility to giant cell arteritis

The Fc gamma receptors have been shown to play important roles in the initiation and regulation of many immunological and inflammatory processes and to amplify and refine the immune response to an infection. We have investigated the hypothesis that polymorphism within the FCGR genetic locus is associated with giant cell arteritis (GCA). Biallelic polymorphisms in FCGR2A, FCGR3A, FCGR3B and FCGR2B were examined for association with biopsy-proven GCA (n = 85) and healthy ethnically matched controls (n = 132) in a well-characterised cohort from Lugo, Spain. Haplotype frequencies and linkage disequilibrium (D') were estimated across the FCGR locus and a model-free analysis performed to determine association with GCA. There was a significant association between FCGR2A-131RR homozygosity (odds ratio (OR) 2.10, 95% confidence interval (CI) 1.12 to 3.77, P = 0.02, compared with all others) and carriage of FCGR3A-158F (OR 3.09, 95% CI 1.10 to 8.64, P = 0.03, compared with non-carriers) with susceptibility to GCA. FCGR haplotypes were examined to refine the extent of the association. The haplotype showing the strongest association with GCA susceptibility was the FCGR2A-FCGR3A 131R-158F haplotype (OR 2.84, P = 0.01 for homozygotes compared with all others). There was evidence of a multiplicative joint effect between homozygosity for FCGR2A-131R and HLA-DRB1*04 positivity, consistent with both of these two genetic factors contributing to the risk of disease. The risk of GCA in HLA-DRB1*04 positive individuals homozygous for the FCGR2A-131R allele is increased almost six-fold compared with those with other FCGR2A genotypes who are HLA-DRB1*04 negative. We have demonstrated that FCGR2A may contribute to the 'susceptibility' of GCA in this Spanish population. The increased association observed with a FCGR2A-FCGR3A haplotype suggests the presence of additional genetic polymorphisms in linkage disequilibrium with this haplotype that may contribute to disease susceptibility. These findings may ultimately provide new insights into disease pathogenesis

Aldebaran b's temperate past uncovered in planet search data

The nearby red giant Aldebaran is known to host a gas giant planetary companion from decades of ground-based spectroscopic radial velocity measurements. Using Gaussian Process-based Continuous Auto-Regressive Moving Average (CARMA) models, we show that these historic data also contain evidence of acoustic oscillations in the star itself, and verify this result with further dedicated ground-based spectroscopy and space-based photometry with the Kepler Space Telescope. From the frequency of these oscillations we determine the mass of Aldebaran to be $1.16 \pm 0.07 \, M_\odot$, and note that this implies its planet will have been subject to insolation comparable to the Earth for some of the star's main sequence lifetime. Our approach to sparse, irregularly sampled time series astronomical observations has the potential to unlock asteroseismic measurements for thousands of stars in archival data, and push to lower-mass planets around red giant stars.Comment: 24 pages, 7 figures (including appendices); submitted to ApJL; paper text, figures, data, and code at https://github.com/farr/Aldebara

Lestaurtinib is a potent inhibitor of anaplastic thyroid cancer cell line models

Anaplastic thyroid cancer (ATC) is a rare and lethal human malignancy with no known effective therapies in the majority of cases. Despite the use of conventional treatments such as chemotherapy, radiation and surgical resection, this disease remains almost universally fatal. In the present study, we identified the JAK2 inhibitor Lestaurtinib as a potent compound when testing against 13 ATC cell lines. Lestaurtinib demonstrated a potent antiproliferative effect in vitro at nanomolar concentrations. Furthermore, Lestaurtinib impeded cell migration and the ability to form colonies from single cells using scratch-wound and colony formation assays, respectively. Flow cytometry was used for cell cycle analysis following drug treatment and demonstrated arrest at the G2/M phase of the cell cycle, indicative of a cytostatic effect. In vivo studies using the chick chorioallantoic membrane xenograft models demonstrated that treatment with Lestaurtinib resulted in a significant decrease in endpoint tumor volume and vascularity using power Doppler ultrasound imaging. Overall, this study provides evidence that Lestaurtinib is a potent antiproliferative agent with potential antiangiogenic activity that warrants further investigation as a targeted therapy for ATC

1958: Abilene Christian College Bible Lectures - Full Text

“GOD” Being the Abilene Christian College Annual Bible Lectures 1958 Price: $3.00 Published by FIRM FOUNDATION PUBLISHING HOUSE Box 77 Austin, Texa

Immediate chest X-ray for patients at risk of lung cancer presenting in primary care: randomised controlled feasibility trial

Background: Achieving earlier stage diagnosis is one option for improving lung cancer outcomes in the United Kingdom. Patients with lung cancer typically present with symptoms to general practitioners several times before referral or investigation. Methods: We undertook a mixed methods feasibility individually randomised controlled trial (the ELCID trial) to assess the feasibility and inform the design of a definitive, fully powered, UK-wide, Phase III trial of lowering the threshold for urgent investigation of suspected lung cancer. Patients over 60, with a smoking history, presenting with new chest symptoms to primary care, were eligible to be randomised to intervention (urgent chest X-ray) or usual care. Results: The trial design and materials were acceptable to GPs and patients. We randomised 255 patients from 22 practices, although the proportion of eligible patients who participated was lower than expected. Survey responses (89%), and the fidelity of the intervention (82% patients X-rayed within 3 weeks) were good. There was slightly higher anxiety and depression in the control arm in participants aged >75. Three patients (1.2%) were diagnosed with lung cancer. Conclusions: We have demonstrated the feasibility of individually randomising patients at higher risk of lung cancer, to a trial offering urgent investigation or usual care