Changing Operating Lists on the Day of Surgery - a Service Evaluation

This study aims to explore how often the operating list is changed on the day of surgery, and the reasons why this may occur. The purpose being to analyse the wider potential impact of changing the list on the day of surgery has on patient safety, patient satisfaction and theatre efficiency. Survey data was collected across a multi-specialty elective operating department. The findings demonstrated a significant (P <0.001) change in operating lists occurred in 37.3% of sessions with a variety of potentially avoidable reasons. We concluded that improved organisation and communication before the planned session could reduce the occurrence of changes, increasing patient safety, theatre efficiency and potentially reducing incidents

Airborne intercomparison of vacuum ultraviolet fluorescence and tunable diode laser absorption measurements of tropospheric carbon monoxide

During the fall 1997 North Atlantic Regional Experiment (NARE 97), two separate intercomparisons of aircraft-based carbon monoxide measurement instrumentation were conducted. On September 2, CO measurements were simultaneously made aboard the National Oceanic and Atmospheric Administration (NOAA) WP-3 by vacuum ultraviolet (VUV) fluorescence and by tunable diode laser absorption spectroscopy (TDLAS), On September 18, an intercomparison flight was conducted between two separate instruments, both employing the VUV fluorescence method, on the NOAA WP-3 and the U,K. Meteorological Office C-130 Hercules. The results indicate that both of the VUV fluorescence instruments and the TDLAS system are capable of measuring ambient CO accurately and precisely with no apparent interferences in 5 s. The accuracy of the measurements, based upon three independent calibration systems, is indicated by the agreement to within 11% with systematic offsets of less than 1 ppbv. In addition, one of the groups participated in the Measurement of Air Pollution From Satellite (MAPS) intercomparison [Novelli ef at., 1998] with a different measurement technique but very similar calibration system, and agreed with the accepted analysis to within 5%. The precision of the measurements is indicated by the variability of the ratio of simultaneous measurements from the separate instruments, This variability is consistent with the estimated precisions of 1.5 ppbv and 2.2 ppbv for the 5 s average results of the C-130 and the WP-3 instruments, respectively, and indicates a precision of approximately 3.6% for the TDLAS instrument. The excellent agreement of the instruments in both intercomparisons demonstrates that significant interferences in the measurements are absent in air masses that ranged from 7 km in the midtroposphere to boundary layer conditions including subtropical marine air and continental outflow with embedded urban plumes. The intercomparison of the two VUV instruments that differed widely in their design indicates that the VUV fluorescence technique for CO measurements is not particularly sensitive to the details of its implementation. These intercomparisons help to establish the reliability of ambient CO measurements by the VUV fluorescence technique

Mesoscale covariance of transport and CO2 fluxes: Evidence from observations and simulations using the WRF-VPRM coupled atmosphere-biosphere model

We developed a modeling system which combines a mesoscale meteorological model, the Weather Research and Forecasting (WRF) model, with a diagnostic biospheric model, the Vegetation Photosynthesis and Respiration (VPRM). The WRF-VPRM modeling system was designed to realistically simulate high-resolution atmospheric CO₂ concentration fields. In the system, WRF takes into account anthropogenic and biospheric CO₂ fluxes and realistic initial and boundary conditions for CO₂ from a global model. The system uses several “tagged” tracers for CO₂ fields from different sources. VPRM uses meteorological fields from WRF and high-resolution satellite indices to simulate biospheric CO₂ fluxes with realistic spatiotemporal patterns. Here we present results from the application of the model for interpretation of measurements made within the CarboEurope Regional Experiment Strategy (CERES). Simulated fields of meteorological variables and CO₂ were compared against ground-based and airborne observations. In particular, the characterization by aircraft measurements turned out to be crucial for the model evaluation. The comparison revealed that the model is able to capture the main observed features in the CO₂ distribution reasonably well. The simulations showed that daytime CO₂ measurements made at coastal stations can be strongly affected by land breeze and subsequent sea breeze transport of CO₂ respired from the vegetation during the previous night, which can lead to wrong estimates when such data are used in inverse studies. The results also show that WRF-VPRM is an effective modeling tool for addressing the near-field variability of CO₂ fluxes and concentrations for observing stations around the globe

Regional carbon fluxes and the effect of topography on the variability of atmospheric CO2.

Using a mesoscale atmospheric circulation model, it is shown that relatively modest topography height differences of ∼500 m over 200 km near Zotino (60°N, 89°E) in central Siberia may generate horizontal gradients in CO<inf>2</inf> concentration in the order of 30 ppm. In a case study for 15 and 16 July 1996, when Lloyd et al. (2001) conducted a convective boundary layer budget experiment in the area, we show that advection of these gradients disturbs the relation between diurnal concentration changes in the boundary layer and the surface fluxes. This demonstrates that mesoscale atmospheric heterogeneity may have severe impact on the applicability of methods to derive the regional-scale fluxes from CO<inf>2</inf> concentrations measurements, such as the convective boundary layer budget method or inverse modeling. It is shown that similar mesoscale gradients are likely to occur at many long-term observation stations and tall towers. We use the modeled concentration fields to quantify the horizontal and vertical variability of carbon dioxide in the atmosphere. In future observation campaigns, mesoscale processes may be best accounted for by measuring horizontal variability over a few hundred kilometers and by attempting to quantify the representation errors as a function of mesoscale conditions. Copyright 2007 by the American Geophysical Union

Neural arbitration between social and individual learning systems

Decision making requires integrating self-gathered information with advice from others. However, the arbitration process by which one source of information is selected over the other has not been fully elucidated. In this study, we formalised arbitration as the relative precision of predictions, afforded by each learning system, using hierarchical Bayesian modelling. In a probabilistic learning task, participants predicted the outcome of a lottery using recommendations from a more informed advisor and/or self-sampled outcomes. Decision confidence, as measured by the number of points participants wagered on their predictions, varied with our relative precision definition of arbitration. Functional neuroimaging demonstrated arbitration signals that were independent of decision confidence and involved modality-specific brain regions. Arbitrating in favour of self-gathered information activated the dorsolateral prefrontal cortex and the midbrain, whereas arbitrating in favour of social information engaged the ventromedial prefrontal cortex and the amygdala. These findings indicate that relative precision captures arbitration between social and individual learning systems at both behavioural and neural levels

Use of airborne CO measurements for Lagrangian of ozone formation and transport in continental plumes

The anthropogenic ozone budget is investigated in remote regions with respect to the influence of emissions of VOC and NO., at source regions, and with regard to the relative roles of ozone formation in the polluted boundary layer (PBL) and in the free troposphere (FT). The investigation makes use of airborne measurements aboard the United Kingdom Meteorological Office (UKMO) C-130 Hercules aircraft obtained during the European project TACIA (Testing Atmospheric Chemistry in Anticyclones) and the UK project ACSOE (Atmospheric Chemistry Studies in Oceanic Environment). High resolution measurements ofCO as a quasi-inert tracer of anthropogenic emissions were made and interpreted . The experimental investigations of anthropogenic plumes in the planetary boundary layer (TACIA) and the remote free troposphere (ACSOE) are interpreted by heuristic model calculations . The model set-up, with modules for transport and chemistry, allows for a separation of these processes in the analysis. The transport module in combination with the CO observations is shown to be a useful tool for the analysis of emissions and transport . Convective transport into the free troposphere is identified by combination of the transport module with satellite data. The interpretation of observations distant from the source regions, with respect to the influence of anthropogenic VOC and NO, emissions on the ozone formation in a plume, is made by an indirect inverse modelling approach. The method involves extensive sensitivity studies regarding various initial VOC and NO,, concentrations, in an EKMA framework. Despite the large degree of abstraction, the results of EKMA plot calculations can be compared to the measurements with the help ofCO as emission tracer and enable the dependency of the observed 03 on anthropogenic VOC and NO,, emissions to be analysed. A central point of this study is the use of statistical test methods for the analysis of the significance of deviations between model results and measurements . Sensitivity studies, regarding the dependence of model results on the variability of input parameters, are analysed with respect to confidence regions of the observations . With these means, the following general conclusions regarding ozone formation in continental plumes transported into source free maritime areas are obtained: The layers of enhanced CO and 03 in the FT, observed during ACSOE flight A575, can only partly be explained by in-situ production of ozone in the FT. Higher 03 production efficiencies on a per-molecule basis of NO,, in the FT compared to the PBL are found to be compensated by the reduced NO, availability in the free troposphere, related to CO. PBL-produced 03 is found not only to be important close to source regions, but also for long range transport within the FT in connection with cloud venting, where it contributes to the tropospherc budget of ozone. The 03 formation within the PBL depends on a multitude of parameters. It is shown for the example of the TACIA flight A581, that the natural variability and uncertainties of these parameters are still too high for an unambiguous interpretation of observed 03 formation in a continental plume with respect to anthropogenic NQ, and VOC emissions. This complicates the task of estimating the influence of export of pollutionderived ozone and its precursors on the remote troposphere