An "informationally robust equilibrium" for two-person nonzero-sum games

Game Theory;Equilibrium Theory

The Association of Surgeons in Training Conference: #ASiT2015 Glasgow

AbstractThe Association of Surgeons in Training (ASiT) is a professional body and registered charity working to promote excellence in surgical training for the benefit of junior doctors and patients alike. ASiT is in-dependent of the National Health Service (NHS), Surgical Royal Colleges, and specialty associations and represents trainees in all ten surgical specialties.ASiT was delighted to welcome a number of distinguished guests and speakers to Glasgow for #ASiT2015. The theme of ‘The Future of Surgery’ delved into challenges surgical training faces, exciting developments into using technology to help patients, a glance at the past with the development of the Glasgow Coma Score and whether mortality truly is the future of measured outcomes. More than £3500 of prizes was awarded by the incoming President, Miss. Rhiannon Harries to the highest scoring papers presented selected from over 1000 abstracts submitted

Exchange Currents in Photoproduction of Baryon Resonances

We calculate photoexcitation amplitudes for several nucleon and delta resonances. We use a chiral quark model including two-body exchange currents. The two-body currents give important contributions. For the delta (1232) and the D13 (1520) we observe that the individual exchange current contributions considerably cancel each other while in the case of the Roper resonance and the S11 (1535) we get a reinforcement of the two-body amplitudes. In comparison with present experimental data, we obtain both for the S11 (1535) and for the Roper resonance an improvement with respect to the impulse approximation.Comment: 9 pages, 1 figur

Understanding the effect of confinement in scanning spreading resistance microscopy measurements

Scanning spreading resistance microscopy (SSRM) is a powerful technique for quantitative two-and three-dimensional carrier profiling of semiconductor devices with sub-nm spatial resolution. However, considering the sub-10 nm dimensions of advanced devices and the introduction of three-dimensional architectures like fin field effect transistor (FinFET) and nanowires, the measured spreading resistance is easily impacted by parasitic series resistances present in the system. The limited amount of material, the presence of multiple interfaces, and confined current paths may increase the total resistance measured by SSRM beyond the expected spreading resistance, which can ultimately lead to an inaccurate carrier quantification. Here, we report a simulation assisted experimental study to identify the different parameters affecting the SSRM measurements in confined volumes. Experimentally, the two-dimensional current confinement is obtained by progressively thinning down uniformly doped blanket silicon on insulator wafers using scalpel SSRM. The concomitant SSRM provides detailed electrical information as a function of depth up to oxide interface. We show that the resistance is most affected by the interface traps in case of a heterogeneous sample, followed by the intrinsic resistance of the current carrying paths. Furthermore, we show that accurate carrier quantification is ensured for typical back contact distances of 1 μm if the region of interest is at least nine times larger than the probe radius. © 2020 Author(s)

Plasma polymerization of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl in a collisional, capacitively coupled radio frequency discharge

Plasma polymerization of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) yields thin films containing stable nitroxide radicals that have properties analogous to that of nitric oxide (NO) without short lifetimes. This property gives TEMPO films a wide variety of potential applications. Typically, control of the final film chemistry is difficult and the plasma discharge conditions must be tailored to in order to maximize the retention of these nitroxide groups during the polymerization and deposition process. In this study, plasma diagnostics and surface analysis of the deposited films were carried out to determine the optimal plasma conditions for the retention of nitroxide groups. These techniques included energy-resolved mass spectrometry, heated planar probe ion current measurements, deposition rate measurements, and x-ray photoelectron spectroscopy (XPS). Results show that operating the plasma with a combination of low input powers and high pressures produces a collisional discharge in which fragmentation of the TEMPO molecule is suppressed, leading to good retention of nitroxide groups. Ion energy distribution functions and quartz crystal microbalance measurements support the soft landing theory of ion deposition on the substrate within this γ-mode, in which the flux of low energy, soft landed ions form the primary contribution to film growth. XPS analysis of deposited polymers shows 75.7% retention of N - O groups in the polymer films deposited in a 25 Pa 5 W discharge. © 2020 Author(s)

Plasma polymerization of isopentyl nitrite at atmospheric pressure: gas phase analysis and surface chemistry

Nitric oxide (NO)-releasing coatings have promising potential for biomedical applications notably in implant safety and wound dressing by promoting healing and reducing bacterial growth. Yet, the production of NO-films remains difficult through classic approaches. In this study, plasma polymerized NO-coatings are produced using a helium-isopentyl nitrite mixture under two power settings and deposited on aluminum samples. Analyses of the plasma phase by mass spectroscopy reveal the presence of nitrosoxy groups (O–N═O) in monomer and quasi-monomer at low power, and a higher fragmentation rate at high power. Static and no-static samples are made and analyzed by X-ray photoelectron spectroscopy showing the presence of these group for both power conditions, with a better retention on the sample's center for the latest

Evaluating G2G for use in Rapid Response Catchments: Final Report

Flood impacts can be severe for rapid response catchments (RRCs). Providing targeted flood warnings is challenging using existing methodologies and on account of the typical absence of river flow gauging. The Pitt Review of the Summer 2007 floods recognised the need for new alert procedures for RRCs able to exploit the new distributed flood forecasting capability being progressed from research into operations. Work on the G2G (Grid-to-Grid) distributed hydrological model was accelerated into operational practice to support 5-day countrywide flood outlooks, a major recommendation of the Pitt Review. The present study aims to explore the potential of G2G to support more frequent and detailed alerts relevant to flood warning in RRCs. Integral to this study is the use of emerging rainfall forecast products, in deterministic and ensemble form, which allow the lead-time of G2G flow forecasts to be extended and given an uncertainty context. This Report sets down the overall scope of the project, provides an introduction to G2G by way of background and then reports on the outcomes of the R&D study. This includes extensive preparatory work on collating historical datasets to support G2G model assessment, both relating to hydrometry and new rainfall forecast products. A framework is developed for assessing G2G in both simulation-mode and forecast-mode (as a function of lead-time) targeted at the RRC requirement. Relevant to the requirement is the RRC Register of points and areas of interest compiled by the Environment Agency, and the characteristics of RRCs (occurring in isolation or in combination): small catchment area, urban/sub-urban land-cover and steep slopes. The assessment framework is first applied assuming perfect knowledge of rainfall observations for past and future times, so as not to confound the analysis with errors from rainfall forecasts. Variability of performance measures across groups of sites is summarised through box and whisker plots, groups being differentiated on size of catchment area and nature of G2G run (simulation, and with the addition of state updating and flow insertion in turn). Skill scores judge how well the model performs in detecting a flood event exceeding a flow threshold, taken as the median annual flood (as an indicator of bankfull flow exceedance for natural channels) and fractional multipliers of it. The skill scores include POD (Probability of Detection) and FAR (False Alarm Ratio). Performance maps of R2 Efficiency, indicating the variability in the observations accounted for by the model, are used to portray the spatial variability of G2G accuracy across the country. G2G performance in small catchments, relevant to the RRC requirement, is best over South West, North East and North West regions; also median performance appears robust from one year to the next. Larger catchments benefit most in forecast-mode from flow insertion, whilst smaller headwater catchments gain particularly from ARMA (AutoRegressive Moving Average) error-prediction. An assessment is made of using deterministic rainfall forecasts from NWP UKV - the Numerical Weather Prediction UK Variable Resolution form of the Met Office Unified Model - in a full emulation of G2G in real-time, and using foreknowledge of rainfall observations as a reference baseline. Forecast quality can deteriorate strongly beyond 12 hours, especially for smaller catchments, whilst for some locations good performance is maintained even for long lead-times. Diagnostic analysis reveals that the UKV rainfall forecasts have patterns of overestimation in some lowland areas (e.g. over London) and leeward of high elevation areas (e.g. north and south Pennines). Overall performance is better in Scotland although there is evidence of UKV overestimating rainfall near the coast at Edinburgh and Elgin in the north. The assessment framework is extended to include rainfall forecast ensembles and probabilistic flood forecasting, using a combination of case-study and longer-term analyses. Blended Ensemble rainfall forecasts are assessed in two forms: forecasts out to 24 hours updated 4 times a day, and nowcasts out to 7 hours updated every 15 minutes. The 24 hour forecasts generally perform well as input to G2G in the case studies, the G2G flow forecasts typically signalling a flood peak 12 to 18 hours in advance and ahead of any observed response for small catchments. New regional summary map displays of the probability of flow threshold exceedances over a forecast horizon, and for increasing levels of severity, are developed to highlight evolving hotspots of flood risk over time. The first ever continuous assessment of G2G probability flow forecasts is reported using national maps of probabilistic skill scores - Relative Operating Characteristic (ROC) Skill Score and Brier Skill Score (BSS) - to spatially assess their performance. It is noted that the short periods available for assessment - a 7½ month period over England & Wales and 4 ½ months over Scotland - limit the analyses to low return period flow thresholds. Half the median (2-year) flood is used although a regional pooled analysis allows some assessment up to 5-year. The G2G probability forecast assessed is the probability of the chosen flow threshold being exceeded at any time over the forecast horizon (taken to be 24 hours). Comparison of these scores when applied to deterministic and probabilistic forecasts from G2G provides strong evidence of the value of G2G ensemble forecasts as an indicator of flood risk over Britain. Noticeably poorer performance indicated by the BSS across Scotland is in part attributed to the short, summer-dominated assessment period. Operational tools available to FFC and the SFFS for using G2G flow ensembles are reviewed and options for improvement identified drawing on the experience and findings of the study. This leads to identifying some work of an operational nature for consideration in Phase 3 of the project. The report closes with a summary of project achievements grouped thematically, a set of recommendations both of a general nature and specific to FFC and SFFS needs, and finally some proposals for consideration under Phase 3 of the G2G for Rapid Response Catchments project. Some key benefits arising from the project are summarised below. • Evidence has been produced that shows G2G has good skill in providing strategic forecasts for RRCs. The evidence is stratified by catchment type (area, urbanisation, headwater), form of forecast (simulation or forecast mode) and nature of rainfall input (raingauge, deterministic forecast, ensemble forecast). • Strong evidence has been presented on the advantage of using an ensemble rainfall forecast as input to G2G to obtain a probabilistic flood forecast for an RRC, relative to an approach where only a single deterministic rainfall and flood forecast is obtained. This indicates better guidance can be given on forecast flood risk for RRCs, improving the level of service provision for such catchments which are currently not well served. • An improved G2G model configuration, exploiting gauged flows from 912 sites and including new locally calibrated parameters, has been delivered and made operational for the FFC with England & Wales coverage. The benefit is improved operational flood forecast accuracy. For Scotland, an enhanced configuration will be delivered to SFFS in Spring 2014. • Detailed recommendations on how the visual presentation of G2G ensemble results could be improved are set down in this report. When further developed and implemented, these will prove of benefit to the preparation of Flood Guidance Statements issued by FFC and the SFFS across Britain

The Value of Information for Populations in Varying Environments

The notion of information pervades informal descriptions of biological systems, but formal treatments face the problem of defining a quantitative measure of information rooted in a concept of fitness, which is itself an elusive notion. Here, we present a model of population dynamics where this problem is amenable to a mathematical analysis. In the limit where any information about future environmental variations is common to the members of the population, our model is equivalent to known models of financial investment. In this case, the population can be interpreted as a portfolio of financial assets and previous analyses have shown that a key quantity of Shannon's communication theory, the mutual information, sets a fundamental limit on the value of information. We show that this bound can be violated when accounting for features that are irrelevant in finance but inherent to biological systems, such as the stochasticity present at the individual level. This leads us to generalize the measures of uncertainty and information usually encountered in information theory