Embedding right-angled Artin groups into graph braid groups

We construct an embedding of any right-angled Artin group $G(\Delta)$ defined by a graph $\Delta$ into a graph braid group. The number of strands required for the braid group is equal to the chromatic number of $\Delta$. This construction yields an example of a hyperbolic surface subgroup embedded in a two strand planar graph braid group.Comment: 8 pages. Final version, appears in Geometriae Dedicata

Do European hospitals have quality and safety governance systems and structures in place?

Internal systems for quality and safety were assessed in 89 hospitals in six European states, by external teams using standardised criteria and procedures, as part of the Methods of Assessing Response to Quality Improvement Strategies (MARQuIS) project. The assessments were made primarily to identify the current use of quality management systems in the sample hospitals, and also to demonstrate a potential tool for comparable assessment of hospitals in general. The large majority of the hospitals had a formal, documented infrastructure to manage quality and safety, but a significant minority had no designated mission, programme or coordination. In two-thirds of hospitals, the governing body was active in defining policy and programmes for improvement, and received reports on quality, safety and patient satisfaction at least once a year. The brief on-site assessments identified systematic variations, within and between countries, in structures and processes of governance and to document the uptake of best practice. Unacceptable variations in practice could be reduced, to the benefit of consumers and providers, by developing and publishing basic organisational standards relevant to all European states. The simple assessment criteria designed for this project could be developed into a practical tool for self-assessment, peer review or benchmarking of hospitals across national borders. This assessment, combined with explicit, relevant and achievable standards, could provide a vehicle to promote the voluntary uptake of best practice and consistency in quality and safety among hospitals in Europe

Searching for Faint Planetary Nebulae Using the Digital Sky Survey

Recent Halpha surveys such as SHS and IPHAS have improved the completeness of the Galactic planetary nebula (PN) census. We now know of ~3,000 PNe in the Galaxy, but this is far short of most estimates, typically ~25,000 or more for the total population. The size of the Galactic PN population is required to derive an accurate estimate of the chemical enrichment rates of nitrogen, carbon, and helium. In addition, a high PN count (~20,000) is strong evidence that most 1-8 Msun main sequence stars will go through a PN phase, while a low count (<10,000) argues that special conditions (e.g., a close binary interaction) are required to form a PN. We describe a technique for finding hundreds more PNe using the existing data collections of the digital sky surveys, thereby improving the census of Galactic PNe.Comment: 11 pages, 7 figures, accepted for publication in the Publications of the Astronomical Society of Australia (PASA), full resolution paper available at http://www.wiyn.org/jacoby_pasa.pd

Reference to index of the sales ledgers of Crisp and Gunn Timber Merchants

This business was founded in 1886 by Frederick H. Crisp, one of the sons of George Crisp who was a timber merchant in partnership with his father Samuel Crisp and later his brother, Alfred. Frederick Crisp built a saw-mill and offices in Melville Street, Hobart. He also had a saw-mill at Ida Bay for local timber. In addition he imported timber from the Baltic and America, and kauri pine from New Zealand and cedar from Queensland. It appears from advertisements that about 1903 or 1904 he merged with Ernest Crisp, the remaining partner of the original Crisp Brothers business founded by his grandfather, and the second ledger is, in fact, marked Ernest Crisp. About 1908 or 1909 he took Mr. Gunn into partnership. The firm supplied cut lengths of various timbers and prepared mouldings, flooring, hand rails, beading, shingles, palings, weather boards, etc. to contractors, builders and individual purchasers in and around Hobart and as far as Franklin, Kelly Basin (West Coast), Swansea, Macquarie Plains, etc. - Transfered to the Tasmanian Archives and Heritage Office (TAHO) - Jan 2013 -www.linc.tas.gov.au/tasmaniasheritag

Interactions between a top order predator and exotic mesopredators in the Australian rangelands

Extent: 15p.An increase in mesopredators caused by the removal of top-order predators can have significant implications for threatened wildlife. Recent evidence suggests that Australia’s top-order predator, the dingo, may suppress the introduced cat and red fox. We tested this relationship by reintroducing 7 foxes and 6 feral cats into a 37 km2 fenced paddock in arid South Australia inhabited by a male and female dingo. GPS datalogger collars recorded locations of all experimental animals every 2 hours. Interactions between species, mortality rates, and postmortems were used to determine the mechanisms of any suppression. Dingoes killed all 7 foxes within 17 days of their introduction and no pre-death interactions were recorded. All 6 feral cats died between 20 and 103 days after release and dingoes were implicated in the deaths of at least 3 cats. Dingoes typically stayed with fox and cat carcasses for several hours after death and/or returned several times in ensuing days. There was no evidence of intraguild predation, interference competition was the dominant mechanism of suppression. Our results support anecdotal evidence that dingoes may suppress exotic mesopredators, particularly foxes. We outline further research required to determine if this suppression translates into a net benefit for threatened prey species.Katherine E. Moseby, Heather Neilly, John L. Read, and Helen A. Cris

The benefits of very low earth orbit for earth observation missions

Very low Earth orbits (VLEO), typically classified as orbits below approximately 450 km in altitude, have the potential to provide significant benefits to spacecraft over those that operate in higher altitude orbits. This paper provides a comprehensive review and analysis of these benefits to spacecraft operations in VLEO, with para-metric investigation of those which apply specifically to Earth observation missions. The most significant benefit for optical imaging systems is that a reduction in orbital altitude improves spatial resolution for a similar payload specification. Alternatively mass and volume savings can be made whilst maintaining a given performance. Similarly, for radar and lidar systems, the signal-to-noise ratio can be improved. Additional benefits include improved geospatial position accuracy, improvements in communications link-budgets, and greater launch vehicle insertion capability. The collision risk with orbital debris and radiation environment can be shown to be improved in lower altitude orbits, whilst compliance with IADC guidelines for spacecraft post-mission lifetime and deorbit is also assisted. Finally, VLEO offers opportunities to exploit novel atmosphere-breathing electric propulsion systems and aerodynamic attitude and orbit control methods. However, key challenges associated with our understanding of the lower thermosphere, aerodynamic drag, the requirement to provide a meaningful orbital lifetime whilst minimising spacecraft mass and complexity, and atomic oxygen erosion still require further research. Given the scope for significant commercial, societal, and environmental impact which can be realised with higher performing Earth observation platforms, renewed research efforts to address the challenges associated with VLEO operations are requiredThis project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 737183Peer ReviewedPostprint (author's final draft

Delay-dependent amplification of a probe pulse via stimulated Rayleigh scattering

Stimulated Rayleigh scattering of pump and probe light pulses of close carrier frequencies is considered. A nonzero time delay between the two pulses is shown to give rise to amplification of the delayed (probe) pulse accompanied by attenuation of the pump, both on resonance and off resonance. In either case, phase-matching effects are shown to provide a sufficiently large gain, which can exceed significantly direct one-photon-absorption losses