Length at maturity in three pelagic sharks (Lamna nasus, Isurus oxyrinchus, and Prionace glauca) from New Zealand

Reproductive data collected from porbeagle, shortfin mako, and blue sharks caught around New Zealand were used to estimate the median length at maturity. Data on clasper development, presence or absence of spermatophores or spermatozeugmata, uterus width, and pregnancy were collected by observers aboard tuna longline vessels. Direct maturity estimates were made for smaller numbers of sharks sampled at recreational fishing competitions. Some data sets were sparse, particularly over the vital maturation length range, but the availability of multiple indicators of maturity made it possible to develop estimates for both sexes of all three species. Porbeagle shark males matured at 140–150 cm fork length and females at about 170–180 cm. New Zealand porbeagles therefore mature at shorter lengths than they do in the North Atlantic Ocean. Shortfin mako males matured at 180–185 cm and females at 275 –285 cm. Blue shark males matured at about 190 –195 cm and females at 170–190 cm; however these estimates were hampered by small sample sizes, difficulty obtaining representative samples from a population segregated by sex and maturity stage, and maturation that occurred over a wide length range. It is not yet clear whether regional differences in median maturity exist for shortfin mako an

Are Radiology request forms adequately filled in? : an audit assessing local practice

Background: Radiology request forms are essential communication tools used by doctors referring patients for radiological investigations. Their importance, however, is highly underestimated. We set out to perform a process audit of the adequacy of completion of such request forms in St. Luke's Hospital, Malta. Methods: A representative sample of 200 randomly selected request forms received by the radiology department in early September 2004 was reviewed. These included requests for a variety of examinations from different departments within St. Luke's Hospital. A database of the collected forms was created, noting which of the various fields were adequately completed. Results: Only 4% of the 200 request forms reviewed were completed in full. The percentages of the various fields completed were: patient's name and surname - 100%; patient's full address - 77%; patient's age - 29%; referring ward - 95%; referring doctor's signature - 100%; referring doctor's name and surname - 34%; name of responsible consultant - 91%; question to be answered - 25%. The patient's clinical background field was filled in 93%. However, these were more often than not incomplete and unable to fulfil their purpose. Conclusions: There is ample room for change in current local practice.peer-reviewe

Static highly elliptical orbits using hybrid low-thrust propulsion

Static highly-elliptical orbits enabled using hybrid solar-sail/solar-electric propulsion are investigated. These newly proposed orbits, termed Taranis orbits, have free selection of ‘critical inclination’ and use low-thrust propulsion to compensate for the drift in argument of perigee caused by Earth’s gravitational field. In this paper, a 12-hr Taranis orbit with an inclination of 90deg is developed to illustrate the principle. The acceleration required to enable this novel orbit is made up partly by the acceleration produced by solar-sails of various characteristic accelerations, and the remainder supplied by the electric thruster. Order of magnitude mission lifetimes are determined, a strawman mass budget is also developed for two system constraints, firstly spacecraft launch-mass is fixed, and secondly the maximum thrust of the thruster is constrained. Fixing maximum thrust increases mission lifetimes, and solar-sails are considered near to mid-term technologies. However, fixing mass results in negligible increases in mission lifetimes for all hybrid cases considered, solar sails also require significant development. This distinction highlights an important contribution to the field, illustrating that addition of a solar-sail to an electric propulsion craft can have negligible benefit when mass is the primary system constraint. Technology requirements are also outlined, including sizing of solar-arrays, propellant tanks and solar sails

Incompressible Even Denominator Fractional Quantum Hall States in the Zeroth Landau Level of Monolayer Graphene

Incompressible even denominator fractional quantum Hall states at fillings $\nu = \pm \frac{1}{2}$ and $\nu = \pm \frac{1}{4}$ have been recently observed in monolayer graphene. We use a Chern-Simons description of multi-component fractional quantum Hall states in graphene to investigate the properties of these states and suggest variational wavefunctions that may describe them. We find that the experimentally observed even denominator fractions and standard odd fractions (such as $\nu=1/3, 2/5$, etc.) can be accommodated within the same flux attachment scheme and argue that they may arise from sublattice or chiral symmetry breaking orders (such as charge-density-wave and antiferromagnetism) of composite Dirac fermions, a phenomenon unifying integer and fractional quantum Hall physics for relativistic fermions. We also discuss possible experimental probes that can narrow down the candidate broken symmetry phases for the fractional quantum Hall states in the zeroth Landau level of monolayer graphene.Comment: 5 page

Citizenship, community, and counter-terrorism : UK security discourse, 2001-2011

This paper analyses a corpus of UK policy documents which sets out national security policy as an exemplar of the contemporary discourse of counter-terrorism in Europe, the USA and worldwide. A corpus of 148 documents (c. 2.8 million words) was assembled to reflect the security discourse produced by the UK government before and after the 7/7 attacks on the London Transport system. To enable a chronological comparison, the two sub-corpora were defined: one relating to a discourse of citizenship and community cohesion (2001-2006); and one relating to the ‘Preventing Violent Extremism’ discourse (2007-2011). Wordsmith Tools (Scott 2008) was used to investigate keywords and patterns of collocation. The results present themes emerging from a comparative analysis of the 100 strongest keywords in each sub- corpus; as well as a qualitative analysis of related patterns of the collocation, focusing inparticular on features of connotation and semantic prosody