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The Binary Population and Spectral Synthesis suite of binary stellar evolution models and synthetic stellar populations provides a framework for the physically motivated analysis of both the integrated light from distant stellar populations and the detailed properties of those nearby. We present a new version 2.1 data release of these models, detailing the methodology by which Binary Population and Spectral Synthesis incorporates binary mass transfer and its effect on stellar evolution pathways, as well as the construction of simple stellar populations. We demonstrate key tests of the latest Binary Population and Spectral Synthesis model suite demonstrating its ability to reproduce the colours and derived properties of resolved stellar populations, including well-constrained eclipsing binaries. We consider observational constraints on the ratio of massive star types and the distribution of stellar remnant masses. We describe the identification of supernova progenitors in our models, and demonstrate a good agreement to the properties of observed progenitors. We also test our models against photometric and spectroscopic observations of unresolved stellar populations, both in the local and distant Universe, finding that binary models provide a self-consistent explanation for observed galaxy properties across a broad redshift range. Finally, we carefully describe the limitations of our models, and areas where we expect to see significant improvement in future versions.
The Shang (c. 1500–1045 BC) and Zhou dynasties (c. 1045–771 BC) of China are famous for their sophisticated ritual bronze vessels. Sourcing the leaded tin-bronze has, however, proved to be a challenge. A new systematic approach to metal chemistry uses trace elements and isotopes to characterise the underlying circulation pattern. It reveals the complexity of the copper sources on which the late Shang capital at Anyang depended for its bronzes, suggesting the transport of copper from distant regions in the south, on the Yangtze, and from north-east China. The new interpretational system furthers our understanding of the network on which successive Chinese dynasties depended for copper, lead and tin, and attempts to give equal weight to the archaeological and chemical data.
We have recently released version 2.0 of the Binary Population and Spectral Synthesis (BPASS) population synthesis code. This is designed to construct the spectra and related properties of stellar populations built from ~200,000 detailed, individual stellar models of known age and metallicity. The output products enable a broad range of theoretical predictions for individual stars, binaries, resolved and unresolved stellar populations, supernovae and their progenitors, and compact remnant mergers. Here we summarise key applications that demonstrate that binary populations typically reproduce observations better than single star models.
The role of episodic mass loss in evolved massive stars is one of the outstanding questions in stellar evolution theory. Integral field spectroscopy of nebulae around massive stars provide information on their recent mass-loss history. η Car is one of the most massive evolved stars and is surrounded by a complex circumstellar environment. We have conducted a three-dimensional morpho-kinematic analysis of η Car’s ejecta outside its famous Homunculus nebula. SHAPE modelling of VLT MUSE data establish unequivocally the spatial cohesion of the outer ejecta and the correlation of ejecta with the soft X-ray emission.
Eta Carinae is one of the most massive observable binaries. Yet determination of its orbital and physical parameters is hampered by obscuring winds. However the effects of the strong, colliding winds changes with phase due to the high orbital eccentricity. We wanted to improve measures of the orbital parameters and to determine the mechanisms that produce the relatively brief, phase-locked minimum as detected throughout the electromagnetic spectrum. We conducted intense monitoring of the He ii λ4686 line in η Carinae for 10 months in the year 2014, gathering ~300 high S/N spectra with ground- and space-based telescopes. We also used published spectra at the FOS4 SE polar region of the Homunculus, which views the minimum from a different direction. We used a model in which the He ii λ4686 emission is produced by two mechanisms: a) one linked to the intensity of the wind-wind collision which occurs along the whole orbit and is proportional to the inverse square of the separation between the companion stars; and b) the other produced by the ‘bore hole’ effect which occurs at phases across the periastron passage. The opacity (computed from 3D SPH simulations) as convolved with the emission reproduces the behavior of equivalent widths both for direct and reflected light. Our main results are: a) a demonstration that the He ii λ4686 light curve is exquisitely repeatable from cycle to cycle, contrary to previous claims for large changes; b) an accurate determination of the longitude of periastron, indicating that the secondary star is ‘behind’ the primary at periastron, a dispute extended over the past decade; c) a determination of the time of periastron passage, at ~4 days after the onset of the deep light curve minimum; and d) show that the minimum is simultaneous for observers at different lines of sight, indicating that it is not caused by an eclipse of the secondary star, but rather by the immersion of the wind-wind collision interior to the inner wind of the primary.
Over the past two decades a clear relation between Gamma-Ray Bursts (GRBs) and some broad-lined Type Ic Supernovae (SNe) has been observed. The use of spectropolarimetry allows us to directly probe the 3D geometry of the unresolved ejecta of SNe, which can help us better understand the physics of their explosion and the SN-GRB connection. We present 7 epochs of spectropolarimetry of the broad-lined Type Ic SN 2014ad and highlight its similarities with SN 1998bw.
We gathered a multiwavelength dataset of two well-known LBVs. We found a complex mass-loss, with evidence of variability, such as has been seen previously. In addition, our data reveal signatures of collimated stellar winds. We propose a new scenario for these two stars where the nebula shaping is influenced by the presence of a companion star and/or fast rotation.
The passage of the planet Venus across the face of the Sun is an astronomical spectacle which no living person is likely to have seen. The phenomenon has played an important role in the history of astronomy and in stimulating world science and geographical discovery during the 18th century. But to Australia the transit of 1769 is of truly momentous significance: during the course of an expedition to the South Seas specially organized to observe it, Lt. James Cook discovered and chartered the east coast of Australia, hoisted the English flag, and took possession in the name of King George III.
The growing number of spastic ataxia of Charlevoix-Saguenay (SACS) gene mutations reported worldwide has broadened the clinical phenotype of autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS). The identification of Quebec ARSACS cases without two known SACS mutation led to the development of a multi-modal genomic strategy to uncover mutations in this large gene and explore phenotype variability.
Search for SACS mutations by combining various methods on 20 cases with a classical French-Canadian ARSACS phenotype without two mutations and a group of 104 sporadic or recessive spastic ataxia cases of unknown cause. Western blot on lymphoblast protein from cases with different genotypes was probed to establish if they still expressed sacsin.
A total of 12 mutations, including 7 novels, were uncovered in Quebec ARSACS cases. The screening of 104 spastic ataxia cases of unknown cause for 98 SACS mutations did not uncover carriers of two mutations. Compounds heterozygotes for one missense SACS mutation were found to minimally express sacsin.
The large number of SACS mutations present even in Quebec suggests that the size of the gene alone may explain the great genotypic diversity. This study does not support an expanding ARSACS phenotype in the French-Canadian population. Most mutations lead to loss of function, though phenotypic variability in other populations may reflect partial loss of function with preservation of some sacsin expression. Our results also highlight the challenge of SACS mutation screening and the necessity to develop new generation sequencing methods to ensure low cost complete gene sequencing.
High pressure is used to tune the emission and band structure of the phosphors Ce3+:Lu2S3 and Ce3+:Lu2SiO5. A significant red shift of the broad 5d → 4f emission of Ce3+ was observed in both phosphors. In Ce3+:Lu2S3, we also observed a significant decrease in the emission intensity of Ce3+ and attribute the quenching to a pressure-induced electronic crossover of the Lu2S3 conduction bandedge with the emitting 5d state of Ce3+. In Ce3+:Lu2SiO5, two Ce3+ sites are present and we observed energy transfer from one site (Ce(2)) to the other (Ce(1)) at low pressure. At high pressure, the energy transfer ceases and emission is no longer observed from the Ce(1) site. We propose an exciton recombination model of the energy transfer process.
Purpose: To assess the prevalence and strength of association of risk factors for falling in Canadian veterans of World War II and Korea and their caregivers.
Methods: Questionnaires were sent to addresses of 3,000 Canadian veterans (response rate = 70%). Risk factors for falls and the frequency of falls and injurious falls in the past 12 months were collected.
Results: Veterans had more risk factors than did caregivers, and more had fallen in the past year (39.8% vs. 29.7%). Risk factors in the logistic model for veterans included lower extremity disability (odds ratio = 1.98, 95% confidence interval 1.5–2.6); lower extremity weakness (OR 1.75, 95% CI 1.3–2.3); worse memory than peers (OR 1.67, 95% CI 1.1–2.5); one or more visits to the family doctor in the past month (OR 1.53, 95% CI 1.2–2.0); and worse memory than 5 years ago (OR 1.36, 95% CI 1.0–1.8).
Conclusions: Veterans appear more frail and prone to falling than their caregivers.
The presence of haemoparasites belonging to the taxa Anaplasma, Bartonella and Trypanosoma was determined among 76 common shrews (Sorex araneus) from Northwest England. Anaplasma phagocytophilum DNA was recovered from the blood of 1 shrew (1·3%), with the amplified 16S rRNA sequence identical to one previously reported from a bank vole (Clethrionomys glareolus). Trypanosoma spp. DNA was detected in 9 shrews (11·8%), the amplified 18S rDNA fragments being indistinguishable from one another, and distinct from previously published data. This represents the first report of trypanosome infection in S. araneus and suggests they are susceptible to an uncharacterized Trypanosoma species. Blood from 11 shrews (14·5%) yielded Bartonella spp., with characterization of isolates using comparative sequence analysis of partial gltA and 16S-23S rRNA intergenic spacer regions revealing 2 different genotypes. Phylogenetic inference from alignment of partial gltA sequences found that both UK S. araneus types formed a well-supported cluster with Bartonella sp. isolated from S. araneus in Sweden. No significant effect of host age, sex, or year of collection was found on prevalence of Bartonella or trypanosome infections. The results of this survey demonstrate that common shrews in the UK are susceptible to haemoparasitic infections, at prevalences similar to those reported from sympatric rodents.
Open incision of the patellar tendon (PT) is thought to promote acute vascular responses which ultimately result in an enhanced degree of tendon repair. Such a clinical procedure is commonly applied to patients with refractory tendinitis. The objective of this study was to quantify the vascular adaptations (both anatomical and physiological) to longitudinal incision of the PT, and the resultant effects on tendon organisation. Fifty-four New Zealand White rabbits were separated into 3 experimental groups and 2 control groups. Experimental groups underwent surgical incision of the right PT, and were assessed 3 d, 10 d and 42 d following injury; normal unoperated controls were evaluated at time zero, and sham-operated controls were evaluated at 3 d to control for the effects of incising the overlying skin. Quantitative measures of PT blood supply (blood flow, microvascular volume) and geometric properties of PT substance were obtained for each PT. Histomorphology was assessed to evaluate vascular remodelling and matrix organisation in the healing PT. Longitudinal open incision surgery of the PT led to rapid increases in both blood flow and vascular volume. The incision of overlying tissues alone (sham-operated) contributed to this measurable increase, and accounted for 36% and 42% of the elevated blood flow and vascular volume respectively at the 3 d interval. In the incised PT, blood flow significantly increased by 3 d compared with both time zero and sham-operated controls, and remained significantly elevated at the 10 d interval. Similarly, vascular volume of the incised PT increased at 3 d compared both with time zero and sham-operated controls. At the 10 d interval, the increase in vascular volume was greatest in the central PT substance. By 42 d both blood flow and vascular volume of the incised tendon had diminished, with only blood flow remaining significantly different from controls. In the contralateral limb, a significant neurogenically mediated vasodilation was measured in the contralateral PTs at both early time intervals, but was not seen by the later 42 d interval. With respect to PT geometric properties in the experimental animals, a larger PT results as the tendon matrix and blood vessels remodel. PT cross-sectional area increased rapidly by 3 d to 1·3 times control values, and remained significantly elevated at 42 d postinjury. Morphological assessments demonstrated the disruption of matrix organisation by vascular and soft tissue components associated with the longitudinal incisions. Substantial changes in matrix organisation persisted at 42 d after surgery. These findings suggest that open longitudinal incision of the PT increases the vascular supply to deep tendon early after injury. These changes probably arise through both vasomotor and angiogenic activity in the tissue. Since PT blood flow and vascular volume return towards control levels after 6 wk but structural features remain disorganised, we propose that vascular remodelling is more rapid and complete than matrix remodelling after surgical incision of the PT.