Individual surgeon mortality rates: can outliers be detected? A national utility analysis

Objectives: There is controversy on the proposed benefits of publishing mortality rates for individual surgeons. In some procedures, analysis at the level of an individual surgeon may lack statistical power. The aim was to determine the likelihood that variation in surgeon performance will be detected using published outcome data. Design: A national analysis surgeon-level mortality rates to calculate the level of power for the reported mortality rate across multiple surgical procedures. Setting: The UK from 2010 to 2014. Participants: Surgeons who performed colon cancer resection, oesophagectomy or gastrectomy, elective aortic aneurysm repair, hip replacement, bariatric surgery or thyroidectomy. Outcomes: The likelihood of detecting an individual with a 30-day, 90-day or in-patient mortality rate of up to 5 times the national mean or median (as available). This was represented using a novel heat-map approach. Results: Overall mortality rates for the procedures ranged from 0.07% to 4.5% and mean/median surgeon volume was between 23 and 75 cases. The national median case volume for colorectal (n=55) and upper gastrointestinal (n=23) cancer resections provides around 20% power to detect a mortality rate of 3 times the national median, while, for hip replacement, this is a rate 5 times the national average. At the mortality rates reported for thyroid (0.08%) and bariatric (0.07%) procedures, it is unlikely a surgeon would perform a sufficient number of procedures in his/her entire career to stand a good chance of detecting a mortality rate 5 times the national average. Conclusions: At present, surgeons with increased mortality rates are unlikely to be detected. Performance within an expected mortality rate range cannot be considered reliable evidence of acceptable performance. Alternative approaches should focus on commonly occurring meaningful outcome measures, with infrequent events analysed predominately at the hospital level

Evolution of density perturbations in a realistic universe

Prompted by the recent more precise determination of the basic cosmological parameters and growing evidence that the matter-energy content of the universe is now dominated by dark energy and dark matter we present the general solution of the equation that describes the evolution of density perturbations in the linear approximation. It turns out that as in the standard CDM model the density perturbations grow very slowly during the radiation dominated epoch and their amplitude increases by a factor of about 4000 in the matter and later dark energy dominated epoch of expansion of the universe.Comment: 19 pages, 4 figure

The first ever anti-football painting: A consideration of the soccer match in John Singer Sargent’s "Gassed"

The paper presents a discussion of Gassed, a large oil painting by John Singer Sargent displayed at the Imperial War Museum in London. Completed in 1919, Gassed is the major achievement from Sargent’s commission as an official war artist at the appointment of the British War Memorials Committee during the latter period of World War I. Prominent in the painting is a group of soldiers, blinded by a mustard gas attack, being lead to a casualty clearing station tent. In the distant background of the painting, another group of soldiers can be seen kitted out in football attire playing a match. The significance of this football imagery is our point of enquiry. As our title suggests, some recent interpretations regard the painting as offering critical reflection, from the time, about the symbolic links between sport and war. However, while the painting may certainly be left open to this type of viewer interpretation, archival and secondary resource material research does not support such a critical intention by the artist. Yet, nor is there evidence that Sargent’s intention was the projection of war-heroism. Rather, Sargent’s endeavour to faithfully represent what he observed allows Gassed to be regarded as a visual record of routine activity behind the lines and of football as an aspect of the daily life of British soldiers during the Great War

Automated Coronal Hole Detection using Local Intensity Thresholding Techniques

We identify coronal holes using a histogram-based intensity thresholding technique and compare their properties to fast solar wind streams at three different points in the heliosphere. The thresholding technique was tested on EUV and X-ray images obtained using instruments onboard STEREO, SOHO and Hinode. The full-disk images were transformed into Lambert equal-area projection maps and partitioned into a series of overlapping sub-images from which local histograms were extracted. The histograms were used to determine the threshold for the low intensity regions, which were then classified as coronal holes or filaments using magnetograms from the SOHO/MDI. For all three instruments, the local thresholding algorithm was found to successfully determine coronal hole boundaries in a consistent manner. Coronal hole properties extracted using the segmentation algorithm were then compared with in situ measurements of the solar wind at 1 AU from ACE and STEREO. Our results indicate that flux tubes rooted in coronal holes expand super-radially within 1 AU and that larger (smaller) coronal holes result in longer (shorter) duration high-speed solar wind streams

Spatial and temporal variations in Pb concentrations and isotopic composition in road dust, farmland soil and vegetation in proximity to roads since cessation of use of leaded petrol in the UK

Results are presented for a study of spatial distributions and temporal trends in concentrations of lead (Pb) from different sources in soil and vegetation of an arable farm in central Scotland in the decade since the use of leaded petrol was terminated. Isotopic analyses revealed that in all of the samples analysed, the Pb conformed to a binary mixture of petrol Pb and Pb from industrial or indigenous geological sources and that locally enhanced levels of petrol Pb were restricted to within 10 m of a motorway and 3 m of a minor road. Overall, the dominant source of Pb was historical emissions from nearby industrial areas. There was no discernible change in concentration or isotopic composition of Pb in surface soil or vegetation over the decade since the ban on the sale of leaded petrol. There was an order of magnitude decrease in Pb concentrations in road dust over the study period, but petrol Pb persisted at up to 43% of the total Pb concentration in 2010. Similar concentrations and spatial distributions of petrol Pb and non petrol Pb in vegetation in both 2001 and 2010, with enhanced concentrations near roads, suggested that redistribution of previously deposited material has operated continuously over that period, maintaining a transfer pathway of Pb into the biosphere. The results for vegetation and soil transects near minor roads provided evidence of a non petrol Pb source associated with roads/traffic, but surface soil samples from the vicinity of a motorway failed to show evidence of such a source

Spherical Curvature Inhomogeneities in String Cosmology

We study the evolution of non-linear spherically symmetric inhomogeneities in string cosmology. Friedmann solutions of different spatial curvature are matched to produce solutions which describe the evolution of non-linear density and curvature inhomogeneities. The evolution of bound and unbound inhomogeneities are studied. The problem of primordial black hole formation is discussed in the string cosmological context and the pattern of evolution is determined in the pre- and post-big-bang phases of evolution.Comment: 19 pages, Latex, 4 figure

Gauge-ready formulation of the cosmological kinetic theory in generalized gravity theories

We present cosmological perturbations of kinetic components based on relativistic Boltzmann equations in the context of generalized gravity theories. Our general theory considers an arbitrary number of scalar fields generally coupled with the gravity, an arbitrary number of mutually interacting hydrodynamic fluids, and components described by the relativistic Boltzmann equations like massive/massless collisionless particles and the photon with the accompanying polarizations. We also include direct interactions among fluids and fields. The background FLRW model includes the general spatial curvature and the cosmological constant. We consider three different types of perturbations, and all the scalar-type perturbation equations are arranged in a gauge-ready form so that one can implement easily the convenient gauge conditions depending on the situation. In the numerical calculation of the Boltzmann equations we have implemented four different gauge conditions in a gauge-ready manner where two of them are new. By comparing solutions solved separately in different gauge conditions we can naturally check the numerical accuracy.Comment: 26 pages, 9 figures, revised thoroughly, to appear in Phys. Rev.

Prevalence and characterization of human mecC methicillin-resistant Staphylococcus aureus isolates in England

Objectives: There are limited data available on the epidemiology and prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in the human population that encode the recently described mecA homologue, mecC. To address this knowledge gap we undertook a prospective prevalence study in England to determine the prevalence of mecC among MRSA isolates.<p></p> Patients and methods: Three hundred and thirty-five sequential MRSA isolates from individual patients were collected from each of six clinical microbiology laboratories in England during 2011–12. These were tested by PCR or genome sequencing to differentiate those encoding mecA and mecC. mecC-positive isolates were further characterized by multilocus sequence typing, spa typing, antimicrobial susceptibility profile and detection of PBP2a using commercially available kits.<p></p> Results: Nine out of the 2010 MRSA isolates tested were mecC positive, indicating a prevalence among MRSA in England of 0.45% (95% CI 0.24%–0.85%). The remainder were mecA positive. Eight out of these nine mecC MRSA isolates belonged to clonal complex 130, the other being sequence type 425. Resistance to non-β-lactam antibiotics was rare among these mecC MRSA isolates and all were phenotypically identified as MRSA using oxacillin and cefoxitin according to BSAC disc diffusion methodology. However, all nine mecC isolates gave a negative result using three different commercial PBP2a detection assays. Conclusions: mecC MRSA are currently rare among MRSA isolated from humans in England and this study provides an important baseline prevalence rate to monitor future changes, which may be important given the increasing prevalence of mecC MRSA reported in Denmark.<p></p&gt