Anglo-American corporate governance and the employment relationship: a case to answer?

The corporate governance environment in the UK and US is generally thought to be hostile to the emergence of cooperative employment relations of the kind exemplified by labour-management partnerships. We discuss case study evidence from the UK which suggests that, contrary to this widespread perception, enduring and proactive partnerships may develop, in conditions where management can convince shareholders of the long-term gains from this approach, and where other regulatory factors operate to extend the time-horizon for financial returns. We conclude that there is more scope than is commonly allowed for measures which could reconcile liquidity in capital markets with cooperation in labour relations competition rather than EC legislationcorporate governance, labour-management partnerships, stakeholding

Broken discs: warp propagation in accretion discs

We simulate the viscous evolution of an accretion disc around a spinning black hole. In general any such disc is misaligned, and warped by the Lense-Thirring effect. Unlike previous studies we use effective viscosities constrained to be consistent with the internal fluid dynamics of the disc. We find that nonlinear fluid effects, which reduce the effective viscosities in warped regions, can promote the breaking of the disc into two distinct planes. This occurs when the Shakura & Sunyaev dimensionless viscosity parameter alpha is ~ 45 degrees. The break can be a long-lived feature, propagating outwards in the disc on the usual alignment timescale, after which the disc is fully co- or counter-aligned with the hole. Such a break in the disc may be significant in systems where we know the inclination of the outer accretion disc to the line of sight, such as some X-ray binaries: the inner disc, and so any jets, may be noticeably misaligned with respect to the orbital plane.Comment: 8 pages, 9 figures. Accepted for publication in MNRA

The long-term evolution of the accreting millisecond X-ray pulsar Swift J1756.9-2508

We present a timing analysis of the 2009 outburst of the accreting millisecond X-ray pulsar Swift J1756.9-2508, and a re-analysis of the 2007 outburst. The source shows a short recurrence time of only ~2 years between outbursts. Thanks to the approximately 2 year long baseline of data, we can constrain the magnetic field of the neutron star to be 0.4x10^8 G < B < 9x10^8 G, which is within the range of typical accreting millisecond pulsars. The 2009 timing analysis allows us to put constraints on the accretion torque: the spin frequency derivative within the outburst has an upper limit of $|\dot{\nu}| < 3x10^-13 Hz/s at the 95% confidence level. A study of pulse profiles and their evolution during the outburst is analyzed, suggesting a systematic change of shape that depends on the outburst phase.Comment: 7 pages, 4 figures, submitted to MNRA

Modelling supermassive black hole growth: towards an improved sub-grid prescription

Accretion onto supermassive black holes (SMBHs) in galaxy formation simulations is frequently modelled by the Bondi-Hoyle formalism. Here we examine the validity of this approach analytically and numerically. We argue that the character of the flow where one evaluates the gas properties is unlikely to satisfy the simple Bondi-Hoyle model. Only in the specific case of hot virialised gas with zero angular momentum and negligible radiative cooling is the Bondi-Hoyle solution relevant. In the opposite extreme, where the gas is in a state of free-fall at the evaluation radius due to efficient cooling and the dominant gravity of the surrounding halo, the Bondi-Hoyle formalism can be erroneous by orders of magnitude in either direction. This may impose artificial trends with halo mass in cosmological simulations by being wrong by different factors for different halo masses. We propose an expression for the sub-grid accretion rate which interpolates between the free-fall regime and the Bondi-Hoyle regime, therefore taking account of the contribution of the halo to the gas dynamics.Comment: 7 pages, 3 figures. Accepted for publication in MNRA

Under-ascertainment of Aboriginality in records of cardiovascular disease in hospital morbidity and mortality data in Western Australia: a record linkage study

<p>Abstract</p> <p>Background</p> <p>Measuring the real burden of cardiovascular disease in Australian Aboriginals is complicated by under-identification of Aboriginality in administrative health data collections. Accurate data is essential to measure Australia's progress in its efforts to intervene to improve health outcomes of Australian Aboriginals. We estimated the under-ascertainment of Aboriginal status in linked morbidity and mortality databases in patients hospitalised with cardiovascular disease.</p> <p>Methods</p> <p>Persons with public hospital admissions for cardiovascular disease in Western Australia during 2000-2005 (and their 20-year admission history) or who subsequently died were identified from linkage data. The Aboriginal status flag in all records for a given individual was variously used to determine their ethnicity (index positive, and in all records both majority positive or ever positive) and stratified by region, age and gender. The index admission was the baseline comparator.</p> <p>Results</p> <p>Index cases comprised 62,692 individuals who shared a total of 778,714 hospital admissions over 20 years, of which 19,809 subsequently died. There were 3,060 (4.9%) persons identified as Aboriginal on index admission. An additional 83 (2.7%) Aboriginal cases were identified through death records, increasing to 3.7% when cases with a positive Aboriginal identifier in the majority (≥50%) of previous hospital admissions over twenty years were added and by 20.8% when those with a positive flag in any record over 20 years were incorporated. These results equated to underestimating Aboriginal status in unlinked index admission by 2.6%, 3.5% and 17.2%, respectively. Deaths classified as Aboriginal in official records would underestimate total Aboriginal deaths by 26.8% (95% Confidence Interval 24.1 to 29.6%).</p> <p>Conclusions</p> <p>Combining Aboriginal determinations in morbidity and official death records increases ascertainment of unlinked cardiovascular morbidity in Western Australian Aboriginals. Under-identification of Aboriginal status is high in death records.</p

Simulations of the formation of stellar discs in the Galactic centre via cloud-cloud collisions

Young massive stars in the central parsec of our Galaxy are best explained by star formation within at least one, and possibly two, massive self-gravitating gaseous discs. With help of numerical simulations, we here consider whether the observed population of young stars could have originated from a large angle collision of two massive gaseous clouds at R approx. 1 parsec from Sgr A*. In all the simulations performed, the post-collision gas flow forms an inner, nearly circular gaseous disc and one or two eccentric outer filaments, consistent with the observations. Furthermore, the radial stellar mass distribution is always very steep, Sigma proportional to R^-2, again consistent with the observations. All of our simulations produce discs that are warped by between 30 to 60 degrees, in accordance with the most recent observations. The 3D velocity structure of the stellar distribution is sensitive to initial conditions (e.g., the impact parameter of the clouds) and gas cooling details. For example, the runs in which the inner disc is fed intermittently with material possessing fluctuating angular momentum result in multiple stellar discs with different orbital orientations, contradicting the observed data. In all the cases the amount of gas accreted by our inner boundary condition is large, enough to allow Sgr A* to radiate near its Eddington limit over approx. 10^5 years. This suggests that a refined model would have physically larger clouds (or a cloud and a disc such as the circumnuclear disc) colliding at a distance of a few parsecs rather than 1 parsec as in our simulations.Comment: 18 pages, 14 figures. Accepted for publication in MNRAS. Minor additions at referee request. Movies of simulations available at http://www.astro.le.ac.uk/~aph11/movies.htm

Effective heat dissipation in an adiabatic near-field transducer for HAMR

To achieve a feasible heat-assisted magnetic recording (HAMR) system, a near-field transducer (NFT) is necessary to strongly focus the optical field to a lateral region measuring tens of nanometres in size. An NFT must deliver sufficient power to the recording medium as well as maintain its structural integrity. The self-heating problem in the NFT causes materials failure that leads to the degradation of the hard disk drive performance. The literature reports NFT structures with physical sizes well below 1 micron which were found to be thermo-mechanically unstable at an elevated temperature. In this paper, we demonstrate an adiabatic NFT to address the central challenge of thermal engineering for a HAMR system. The NFT is formed by an isosceles triangular gold taper plasmonic waveguide with a length of 6 µm and a height of 50 nm. Our study shows that in the full optically and thermally optimized system, the NFT efficiently extracts the incident light from the waveguide core and can improve the shape of the heating source profile for data recording. The most important insight of the thermal performance is that the recording medium can be heated up to 866 K with an input power of 8.5 mW which is above the Curie temperature of the FePt film while maintaining the temperature in the NFT at 390 K without a heat spreader. A very good thermal efficiency of 5.91 is achieved also. The proposed structure is easily fabricated and can potentially reduce the NFT deformation at a high recording temperature making it suitable for practical HAMR application

Speciation of phosphorus in a fertilized, reduced-till soil system: in-field treatment incubation study

Citation: Khatiwada, Raju, Ganga M. Hettiarachchi, David B. Mengel, and Mingwei Fei. “Speciation of Phosphorus in a Fertilized, Reduced-Till Soil System: In-Field Treatment Incubation Study.” Soil Science Society of America Journal 76, no. 6 (2012): 2006–18. https://doi.org/10.2136/sssaj2011.0299.Phosphorus management in reduced-tillage systems is a great concern for farmers. Conclusive positive results of deep-banding P fertilizers compared with broadcast application and the chemistry of reduced-tillage systems remain unclear. Knowledge of the dominant solid P species present in soil following application of P fertilizers and the resulting potential P availability would help us understand and efficiently manage P in reduced-tillage systems. The objective of this research was to study the influence of placement (broadcast vs. deep-band P), fertilizer source (granular vs. liquid P), and time on the reaction products of P under field conditions. Changes in soil pH, resin-extractable P, total P, and speciation of P were determined at different distances from the point of fertilizer application at 5 wk and 6 mo after P application at a rate of 75 kg ha−1 to a soil system that was under long-term reduced tillage. Resin-extractable P was lower for broadcast treatments compared with deep-band treatments for both time periods. Resin-extractable P was greater in the liquid P-treated soils than in the granular P-treated soils. Speciation results showed that granular P fertilizers tended to form Fe–P-like forms, whereas liquid forms remained in adsorbed P-like forms in the soil 5 wk after application; moreover, speciation results showed granular P fertilizers precipitated less when deep-banded. During the 6-mo period following application, reaction products of broadcast granular, broadcast liquid, and deep-band granular fertilizers transformed to Ca-phosphate or mixtures of Ca-, Fe- and adsorbed-phosphate-like forms, whereas deep-band liquid P remained as mainly adsorbed P-like forms. Deep-banding of P would most likely provide a solution that is both agronomically and environmentally efficient for reduced-till farmers