Conservative permutation models of two-dimensional fluid flow : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Mathematics at Massey University

At a meeting of Massey University Mathematics Department staff and students on 20 March 1997, a project to model fluid flow by constructing successive permutations of lattice cells was discussed. Several assumptions about the fluid being modelled were necessary to make the problem manageable, the chief ones being that the fluid would be two dimensional, ideal and in-compressible. Two square lattice models were developed, one Eulerian and the other more Lagrangian, in which the lattice cells were each initially assigned a value of a vorticity function. The time evolution of these models consisted of finding a permutation of the cells that was "close" to the fluid flow, then permuting the fixed initial vorticity values according to this lattice map. Justification of this method followed from consequences of the assumptions, including advection of vorticities, and the invertibility and area-preserving nature of the fluid flow map. Reliance was placed on two previously published papers: one containing a result guaranteeing that such permutations are possible in certain circumstances, and the other providing the key to their practical construction. An essential algorithm in the latter paper relies on a theorem concerning the selection of a set of distinct elements from several sets. Also as a result of the assumptions, the enstrophy, total vorticity and kinetic energy of such hypothetical fluid flow is conserved, although tests neither conclusively confirmed nor denied all conserving properties of the models

Measurement of Spin-Orbit Alignment in an Extrasolar Planetary System

We determine the stellar, planetary, and orbital properties of the transiting planetary system HD 209458 through a joint analysis of high-precision radial velocities, photometry, and timing of the secondary eclipse. Of primary interest is the strong detection of the Rossiter-McLaughlin effect, the alteration of photospheric line profiles that occurs because the planet occults part of the rotating surface of the star. We develop a new technique for modeling this effect and use it to determine the inclination of the planetary orbit relative to the apparent stellar equator (λ = -4º.4 ± 1º.4), and the line-of-sight rotation speed of the star (v sin /_★ = 4.70 ± 0.16 km s^(-1)). The uncertainty in these quantities has been reduced by an order of magnitude relative to the pioneering measurements by Queloz and collaborators. The small but nonzero misalignment is probably a relic of the planet formation epoch, because the expected timescale for tidal coplanarization is larger than the age of the star. Our determination of v sin /★ is a rare case in which rotational line broadening has been isolated from other broadening mechanisms

Measurement of the Spin-Orbit Alignment in the Exoplanetary System HD 189733

We present spectroscopy of a transit of the exoplanet HD 189733b. By modeling the Rossiter-McLaughlin effect (the anomalous Doppler shift due to the partial eclipse of the rotating stellar surface), we find the angle between the sky projections of the stellar spin axis and orbit normal to be lambda = -1.4 +/- 1.1 deg. This is the third case of a ``hot Jupiter'' for which lambda has been measured. In all three cases lambda is small, ruling out random orientations with 99.96% confidence, and suggesting that the inward migration of hot Jupiters generally preserves spin-orbit alignment.Comment: ApJ Letters, in pres

Measurement of the Spin-Orbit Angle of Exoplanet HAT-P-1b

We present new spectroscopic and photometric observations of the HAT-P-1 planetary system. Spectra obtained during three transits exhibit the Rossiter-McLaughlin effect, allowing us to measure the angle between the sky projections of the stellar spin axis and orbit normal, \lambda = 3.7 +/- 2.1 degrees. The small value of \lambda for this and other systems suggests that the dominant planet migration mechanism preserves spin-orbit alignment. Using two new transit light curves, we refine the transit ephemeris and reduce the uncertainty in the orbital period by an order of magnitude. We find a upper limit on the orbital eccentricity of 0.067, with 99% confidence, by combining our new radial-velocity measurements with those obtained previously.Comment: 28 total pages, 4 figures, 4 tables, ApJ Accepte

Jean Briggs's Never in Anger as an Ethnography of Experience

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66542/2/10.1177_0308275X9301300406.pd

Garotas de loja, história social e teoria social [Shop Girls, Social History and Social Theory]

Shop workers, most of them women, have made up a significant proportion of Britain’s labour force since the 1850s but we still know relatively little about their history. This article argues that there has been a systematic neglect of one of the largest sectors of female employment by historians and investigates why this might be. It suggests that this neglect is connected to framings of work that have overlooked the service sector as a whole as well as to a continuing unease with the consumer society’s transformation of social life. One element of that transformation was the rise of new forms of aesthetic, emotional and sexualised labour. Certain kinds of ‘shop girls’ embodied these in spectacular fashion. As a result, they became enduring icons of mass consumption, simultaneously dismissed as passive cultural dupes or punished as powerful agents of cultural destruction. This article interweaves the social history of everyday shop workers with shifting representations of the ‘shop girl’, from Victorian music hall parodies, through modernist social theory, to the bizarre bombing of the Biba boutique in London by the Angry Brigade on May Day 1971. It concludes that progressive historians have much to gain by reclaiming these workers and the service economy that they helped create

The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy

Background: The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utilisation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations. Methods: Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves. Results: After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p  90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score. Conclusion: The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care