Aura Microwave Limb Sounder Observations of Dynamics and Transport During the Record-Breaking 2009 Arctic Stratospheric Major Warming

A major stratospheric sudden warming (SSW) in January 2009 was the strongest and most prolonged on record. Aura Microwave Limb Sounder (MLS) observations are used to provide an overview of dynamics and transport during the 2009 SSW, and to compare with the intense, long-lasting SSW in January 2006. The Arctic polar vortex split during the 2009 SSW, whereas the 2006 SSW was a vortex displacement event. Winds reversed to easterly more rapidly and reverted to westerly more slowly in 2009 than in 2006. More mixing of trace gases out of the vortex during the decay of the vortex fragments, and less before the fulfillment of major SSW criteria, was seen in 2009 than in 2006; persistent well-defined fragments of vortex and anticyclone air were more prevalent in 2009. The 2009 SSW had a more profound impact on the lower stratosphere than any previously observed SSW, with no significant recovery of the vortex in that region. The stratopause breakdown and subsequent reformation at very high altitude, accompanied by enhanced descent into a rapidly strengthening upper stratospheric vortex, were similar in 2009 and 2006. Many differences between 2006 and 2009 appear to be related to the different character of the SSWs in the two years

Solar Occultation Satellite Data and Derived Meteorological Products: Sampling Issues and Comparisons with Aura MLS

Derived Meteorological Products (DMPs, including potential temperature (theta), potential vorticity, equivalent latitude (EqL), horizontal winds and tropopause locations) have been produced for the locations and times of measurements by several solar occultation (SO) instruments and the Aura Microwave Limb Sounder (MLS). DMPs are calculated from several meteorological analyses for the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer, Stratospheric Aerosol and Gas Experiment II and III, Halogen Occultation Experiment, and Polar Ozone and Aerosol Measurement II and III SO instruments and MLS. Time-series comparisons of MLS version 1.5 and SO data using DMPs show good qualitative agreement in time evolution of O3, N2O, H20, CO, HNO3, HCl and temperature; quantitative agreement is good in most cases. EqL-coordinate comparisons of MLS version 2.2 and SO data show good quantitative agreement throughout the stratosphere for most of these species, with significant biases for a few species in localized regions. Comparisons in EqL coordinates of MLS and SO data, and of SO data with geographically coincident MLS data provide insight into where and how sampling effects are important in interpretation of the sparse SO data, thus assisting in fully utilizing the SO data in scientific studies and comparisons with other sparse datasets. The DMPs are valuable for scientific studies and to facilitate validation of non-coincident measurements

Surgeon length of service and risk-adjusted outcomes: linked observational analysis of the UK National Adult Cardiac Surgery Audit Registry and General Medical Council Register

OBJECTIVES: To explore the relationship between in-hospital mortality following adult cardiac surgery and the time since primary clinical qualification for the responsible consultant cardiac surgeon (a proxy for experience). DESIGN: Retrospective analysis of prospectively collected national registry data over a 10-year period using mixed-effects multiple logistic regression modelling. Surgeon experience was defined as the time between the date of surgery and award of primary clinical qualification. SETTING: UK National Health Service hospitals performing cardiac surgery between January 2003 and December 2012. PARTICIPANTS: All patients undergoing coronary artery bypass grafts and/or valve surgery under the care of a consultant cardiac surgeon. MAIN OUTCOME MEASURES: All-cause in-hospital mortality. RESULTS: A total of 292,973 operations performed by 273 consultant surgeons (with lengths of service from 11.2 to 42.0 years) were included. Crude mortality increased approximately linearly until 33 years service, before decreasing. After adjusting for case-mix and year of surgery, there remained a statistically significant (p = 0.002) association between length of service and in-hospital mortality (odds ratio 1.013; 95% CI 1.005–1.021 for each year of ‘experience’). CONCLUSIONS: Consultant cardiac surgeons take on increasingly complex surgery as they gain experience. With this progression, the incidence of adverse outcomes is expected to increase, as is demonstrated in this study. After adjusting for case-mix using the EuroSCORE, we observed an increased risk of mortality in patients operated on by longer serving surgeons. This finding may reflect under-adjustment for risk, unmeasured confounding or a real association. Further research into outcomes over the time course of surgeon's careers is required

Autotransfusion decreases blood usage following cardiac surgery - a prospective randomized trial

Introduction: 10% of blood issued by the National Blood Service (220 000) is utilised in cardiac procedures. Transfusion reactions, infection risk and cost should stimulate us to decrease this transfusion rate. We tested the efficacy of autotransfusion of washed postoperative mediastinal fluid in a prospective randomized trial.Patients and methods: 166 patients undergoing coronary artery bypass grafting (CABG), valve or CABG+valve procedures were randomized into three groups. The indication for transfusion was a postoperative haemoglobin (Hb) <10g/l or a packed cell volume (PCV) <30. When applicable, group A patients received washed post-operative drainage fluid. Group B all received blood processed from the cardiopulmonary bypass (CPB) circuit following separation from CPB and if appropriate washed post-operative drainage fluid. Group C were controls. Groups were compared using analysis of variance.Results: There was no significant difference in age, sex, type of operation, CPB time and preoperative Hb and PCV between the groups. Blood requirements were as shown. [see table 3 in main text]Twelve patients in group A and 10 in group B did not require a homologous transfusion following processing of the mediastinal drainage fluid.Conclusion: Autotransfusion of washed postoperative mediastinal fluid can decrease the amount of homologous blood transfused following cardiac surgery. There was no demonstrable benefit in processing blood from the CPB circuit as well as mediastinal drainage fluid

Risk of reoperation for structural failure of aortic and mitral tissue valves

In order to assess the risk of reoperation in the case of a failing stented tissue valve, 259 patients (118 males, 141 females; mean age 60.1 ± 15.4 years) underwent redo valve replacement. Of these patients, 94 (36.3%) underwent redo aortic valve replacement (AVR), 105 (40.5%) redo mitral valve replacement (MVR), and 60 (23.2%) redo aortic and mitral valve replacement (DVR). Twenty patients (7.7%) had previous coronary artery bypass grafting (CABG); further CABG were performed in 32 cases (12.4%). Preoperatively, 216 patients (83.3%) were in NYHA functional class III or IV. Early mortality was (6.5%; n = 17). A higher preoperative NHYA status (p <0.0004) and emergency surgery (p <0.0001) were associated with an increased risk of operative death. Age at operation (p = 0.45), previous CABG (p = 0.45), position of the valve replaced (p = 0.2), type of implant (p = 0.06) and presence of coronary artery disease (p = 0.51) were not associated with a significant risk of operative mortality. A failing tissue valve may be replaced, with acceptable operative mortality and morbidity. The trend towards reducing the age at which tissue valve implantation is performed may be justified

Estimating and Reporting Uncertainties in Remotely Sensed Atmospheric Composition and Temperature

Remote sensing of atmospheric state variables typically relies on the inverse solution of the radiative transfer equation. An adequately characterized retrieval provides information on the uncertainties of the estimated state variables as well as on how any constraint or a priori assumption affects the estimate. Reported characterization data should be intercomparable between different instruments, empirically validatable, grid-independent, usable without detailed knowledge of the instrument or retrieval technique, traceable and still have reasonable data volume. The latter may force one to work with representative rather than individual characterization data. Many errors derive from approximations and simplifications used in real-world retrieval schemes, which are reviewed in this paper, along with related error estimation schemes. The main sources of uncertainty are measurement noise, calibration errors, simplifications and idealizations in the radiative transfer model and retrieval scheme, auxiliary data errors, and uncertainties in atmospheric or instrumental parameters. Some of these errors affect the result in a random way, while others chiefly cause a bias or are of mixed character. Beyond this, it is of utmost importance to know the influence of any constraint and prior information on the solution. While different instruments or retrieval schemes may require different error estimation schemes, we provide a list of recommendations which should help to unify retrieval error reporting

Metabolic responses to prolonged consumption of glucose- and fructose-sweetened beverages are not associated with postprandial or 24-h glucose and insulin excursions123

Background: Consumption of sugar-sweetened beverages has been shown to be associated with dyslipidemia, insulin resistance, fatty liver, diabetes, and cardiovascular disease. It has been proposed that adverse metabolic effects of chronic consumption of sugar-sweetened beverages are a consequence of increased circulating glucose and insulin excursions, ie, dietary glycemic index (GI)