ABSTRACT
We provide a post-mission assessment of the science and data from the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) investigation on the NASA Van Allen Probes mission. An overview of important scientific results is presented, covering all of the key wave modes and DC magnetic fields measured by EMFISIS. Discussion of the data products, which are publicly available, follows to provide users with guidance on characteristics and known issues of the measurements. We present guidance on the correct use of derived products, in particular, the wave-normal analysis (WNA) which yields fundamental wave properties such as polarization, ellipticity, and Poynting flux. We also give information about the plasma density derived from measuring the upper hybrid line in the inner magnetosphere.
ABSTRACT
Plumes have been identified as an access region for chorus waves to enter the plasmasphere. Here, for the first time, chorus wave properties are parameterized by distance from the plume boundary. Case studies and statistical analysis indicate that the polar wave vector angle, θ k , of chorus becomes more oblique near the plume edge. Occurrence rates of θ k > 35° on the plume boundary are approximately double that observed further away from the plume. Whilst the increase in θ k is apparent on both plume edges, the distribution of θ k exhibits different behavior between the Eastward and Westward boundaries. In general, the distribution of azimuthal wave vector angles, Ï k , is symmetric about the anti-Earthwards direction. However, near the Eastward plume boundary, an Eastwards skew of Ï k is reported. This result provides new insight on chorus propagation in the context of the chorus-to-hiss mechanism, and has implications for quantifying wave-particle interactions in the near-plume region.
ABSTRACT
PURPOSE: This systematic review aims to assess whether overall survival, mortality, morbidity, length of stay and cost of performing oesophagectomy are related to surgical volume. METHODS: A systematic search strategy from 1997 until December 2006 was used to retrieve relevant studies. Inclusion of articles was established through application of a predetermined protocol, independent assessment by two reviewers and a final consensus decision. RESULTS: A total of 55 studies were identified of which 27 studies, representing 68 882 patients, met the inclusion criteria. Twenty-one of these solely examined hospital volume, 5 examined both hospital and surgeon volume, and 1 examined surgeon volume in isolation. All but one of the studies were retrospective in nature, and because of the heterogeneity of the literature, no meta-analysis could be performed. Of the studies exploring the relationship between hospital volume and mortality, 20 reported a statistically significant benefit to large volume centres. Five of six included studies showed significant evidence for a reduced mortality risk with greater surgeon volume. CONCLUSIONS: Based on the evidence from these retrospective studies, oesophagectomy performed in high volume centres would appear to be associated with better outcome compared with low volume centres.
