PST11 THE USE OF MULTI-CRITERIA DECISION METHODS IN HEALTH CARE. DOES METHOD USED INFLUENCE OUTCOME?

OBJECTIVES: To investigate how the choice of multicriteria decision method influences outcome (ranking criteria and criteria weights). Population. A convenience sample of 28 subjects, 12 healthy and 16 cognitively impaired. METHODS: Based on a literature review, 5 multicriteria methods were chosen for comparison including: Kepner-tregoe analysis (KTA), simple multi attribute rating technique (SMART), SMART using swing weights (SWING), Analytic Hierarchy Process (AHP) and Conjoint Analysis (CA). Four attributes of treatment were identified (impact, duration, and end-result of treatment and associated risks). Subjects were asked to both rank and rate the importance of these attributes with each method. The order of methods was randomized and the total length of the interview was restricted to one hour. Some subjects therefore did not use all methods. Subjects were interviewed either once (n = 14) or twice (n = 14) (Only the results of the first measurement are presented) RESULTS: The highest percentages of rank reversals were found between CA and other methods (55–62%). The lowest percentage of rank reversals was between KTA and SMART (18%). The percentage of rank reversals was significantly higher in impaired population (An average of 54% compared to 36% in unimpaired population). When comparing actual weights, AHP and SMART correlate highly with all other methods except CA. CONCLUSIONS: The high percentages in rank reversal and divergent correlation between individual weights (especially CA compared to other methods) show that the method chosen influences outcome. This has to be taken into account when the ranks or weights are used in multi-criteria decision analysis to make actual treatment decisions. The dissimilar methodology of CA might explain the high percentages of rank-reversals and low correlation between this method and other. Also, the design of the survey might have influenced CA weights and ranking

Yangian in the Twistor String

We study symmetries of the quantized open twistor string. In addition to global PSL(4|4) symmetry, we find non-local conserved currents. The associated non-local charges lead to Ward identities which show that these charges annihilate the string gluon tree amplitudes, and have the same form as symmetries of amplitudes in N=4 super conformal Yang Mills theory. We describe how states of the open twistor string form a realization of the PSL(4|4) Yangian superalgebra.Comment: 37 pages, 4 figure

The HadCM3 contribution to PlioMIP phase 2

We present the UK's input into the Pliocene Model Intercomparison Project phase 2 (PlioMIP2) using the Hadley Centre Climate Model version 3 (HadCM3). The 400 ppm CO2 Pliocene experiment has a mean annual surface air temperature that is 2.9 ∘C warmer than the pre-industrial and a polar amplification of between 1.7 and 2.2 times the global mean warming. The Pliocene Research Interpretation and Synoptic Mapping (PRISM4) enhanced Pliocene palaeogeography accounts for a warming of 1.4 ∘C, whilst the CO2 increase from 280 to 400 ppm leads to a further 1.5 ∘C of warming. Climate sensitivity is 3.5 ∘C for the pre-industrial and 2.9 ∘C for the Pliocene. Precipitation change between the pre-industrial and Pliocene is complex, with geographic and land surface changes primarily modifying the geographical extent of mean annual precipitation. Sea ice fraction and areal extent are reduced during the Pliocene, particularly in the Southern Hemisphere, although they persist through summer in both hemispheres. The Pliocene palaeogeography drives a more intense Pacific and Atlantic meridional overturning circulation (AMOC). This intensification of AMOC is coincident with more widespread deep convection in the North Atlantic. We conclude by examining additional sensitivity experiments and confirm that the choice of total solar insolation (1361 vs. 1365 Wm−2) and orbital configuration (modern vs. 3.205 Ma) does not significantly influence the anomaly-type analysis in use by the Pliocene community

The PRISM4 (mid-Piacenzian) paleoenvironmental reconstruction

The mid-Piacenzian is known as a period of relative warmth when compared to the present day. A comprehensive understanding of conditions during the Piacenzian serves as both a conceptual model and a source for boundary conditions and means of verification of global climate model experiments. In this paper we present the PRISM4 reconstruction, a palaeoenvironmental reconstruction of the mid-Piacenzian (~3 Ma) containing data for palaeogeography, land and sea-ice, sea-surface temperature, vegetation, soils and lakes. Our retrodicted palaeogeography takes into account glacial isostatic adjustments and changes in dynamic topography. Soils and lakes, both significant as land surface features, are introduced to the PRISM reconstruction for the first time. Sea-surface temperature and vegetation reconstructions are unchanged but now have confidence assessments. The PRISM4 reconstruction is being used as boundary condition data for the Pliocene Model Intercomparison Project, Phase 2 (PlioMIP2) experiments

Atmospheric carbon dioxide, ice sheet and topographic constraints on palaeo moisture availability in Asia

Today, the hydrological regime in East and South Asia is dominated by the monsoons, whilst central Asia is characterized as arid. Studies that have examined the onset of aridity and the intensification of the monsoons in Asia have generated significant debate, especially in respect to the timing of monsoon onset and how this relates to the potential causal mechanisms. The uplift of the Tibetan Plateau, the retreat of the Paratethys Sea, and the global cooling after the Eocene/Oligocene transition are all considered major drivers of Asian aridity and monsoonal intensification. However, little is known about each of these factor's contribution to the development of modern monsoon behaviour. Here, for the first time, we perform sensitivity simulations of a fully coupled ocean–atmosphere climate model (HadCM3) to investigate the effect of the Greenland and Antarctic ice-sheets formation, atmospheric carbon dioxide (CO2) variability, and Tibetan Plateau uplift on East Central Asian aridity and monsoon driven precipitation. We focus on three individual regions, the South Asian Monsoon, the East Asian Monsoon and the Arid East Central Asia and we present the annual precipitation cycle and the moisture availability over each region. Our results show that of the parameters investigated the primary control on Asian hydroclimate is the topography of the Tibetan Plateau. Furthermore, our results highlight that the significance of each forcing depends on the component of the hydrological region and factors studied, a factor that proxy interpretation need to take into consideration

Scale without Conformal Invariance at Three Loops

We carry out a three-loop computation that establishes the existence of scale without conformal invariance in dimensional regularization with the MS scheme in d=4-epsilon spacetime dimensions. We also comment on the effects of scheme changes in theories with many couplings, as well as in theories that live on non-conformal scale-invariant renormalization group trajectories. Stability properties of such trajectories are analyzed, revealing both attractive and repulsive directions in a specific example. We explain how our results are in accord with those of Jack & Osborn on a c-theorem in d=4 (and d=4-epsilon) dimensions. Finally, we point out that limit cycles with turning points are unlike limit cycles with continuous scale invariance.Comment: 21 pages, 3 figures, Erratum adde

Calogero-Sutherland Approach to Defect Blocks

Extended objects such as line or surface operators, interfaces or boundaries play an important role in conformal field theory. Here we propose a systematic approach to the relevant conformal blocks which are argued to coincide with the wave functions of an integrable multi-particle Calogero-Sutherland problem. This generalizes a recent observation in 1602.01858 and makes extensive mathematical results from the modern theory of multi-variable hypergeometric functions available for studies of conformal defects. Applications range from several new relations with scalar four-point blocks to a Euclidean inversion formula for defect correlators.Comment: v2: changes for clarit

Warm fjords and vegetated landscapes in early Pliocene East Antarctica

The response of the Antarctic ice sheets to future warming is uncertain. The IPCC are predicting minimal melt from Antarctica while others suggest increased meltwater contributions are possible. The Pliocene period (5.333 Ma to 2.58 Ma) may provide insights into future ice sheet response, because atmospheric CO2 concentrations were similar to today (350-450 ppmv) and the earth surface was between 2 °C and 4 °C warmer than the preindustrial conditions. Geological records indicate that Antarctica's ice sheets were smaller and more dynamic at this time and many sea-level estimates require meltwater input from the Greenland, West (WAIS) and East Antarctic Ice sheets (EAIS). However, only a few records exist proximal to the Antarctic ice sheet which allow for reconstruction of the Pliocene climate state. We present a multiproxy climate reconstruction from a sedimentary succession that was deposited in an ancient fjord within the Transantarctic Mountains, covering discrete intervals between the early Pliocene and the late Pleistocene. In contrast to modern frigid conditions, our records indicate sea surface temperatures of about 5.6 °C at c. 4.1 Ma, the presence of a plant community at the fjord margins and evidence of soil formation. Simulations of potential vegetation cover in the Pliocene indicate our reconstruction is most compatible with a complete collapse of the WAIS and a large scale retreat of the EAIS from the subglacial basins with atmospheric CO2 levels of less than 450 ppmv. Our study indicates that under present day atmospheric CO2 conditions, in the early Pliocene, the Antarctic ice sheets retreated significantly. Understanding the mechanisms driving this large-scale ice sheet retreat would enable us to assess whether current atmospheric CO2 concentrations will lead to the same ice sheet configuration once the Earth system has come to a new equilibrium state

Modelling ice sheet evolution and atmospheric CO2 during the Late Pliocene

In order to investigate the relation between ice sheets and climate in a warmer-than-present world, recent research has focussed on the Late Pliocene, 3.6 to 2.58 million years ago. It is the most recent period in Earth's history when such a warm climate state existed for a significant duration of time. Marine Isotope Stage (MIS) M2 (∼3.3 Myr ago) is a strong positive excursion in benthic oxygen records in the middle of the otherwise warm and relatively stable Late Pliocene. However, the relative contributions to the benthic δ18O signal from deep ocean cooling and growing ice sheets are still uncertain. Here, we present results from simulations of the Late Pliocene with a hybrid ice-sheet–climate model, showing a reconstruction of ice sheet geometry, sea level and atmospheric CO2. Initial experiments simulating the last four glacial cycles indicate that this model yields results which are in good agreement with proxy records in terms of global mean sea level, benthic oxygen isotope abundance, ice-core-derived surface temperature and atmospheric CO2 concentration. For the Late Pliocene, our results show an atmospheric CO2 concentration during MIS M2 of 233–249 ppmv and a drop in global mean sea level of 10 to 25 m. Uncertainties are larger during the warmer periods leading up to and following MIS M2. CO2 concentrations during the warm intervals in the Pliocene, with sea-level high stands of 8–14 m above the present day, varied between 320 and 400 ppmv, lower than indicated by some proxy records but in line with earlier model reconstructions

The Relationship between ECOG-PS, mGPS, BMI/WL Grade and Body Composition and Physical Function in Patients with Advanced Cancer

Cancer remains one of the leading causes of mortality worldwide and the associated reduction in physical function has a marked impact on both quality of life and survival. The aim of the present study was to examine the relationship between Eastern Cooperative Oncology Group-Performance status (ECOG-PS), modified Glasgow Prognostic Score (mGPS), Body Mass Index/Weight Loss grade (BMI/WL grade), and Computerised Tomography (CT)-derived body composition measurement and physical function in patients with advanced cancer. Nine sites contributed prospective data on patient demographics, ECOG-PS, mGPS, physical function tests, and CT-derived body composition. Categorical variables were analysed using χ2 test for linear-by-linear association, or χ2 test for 2-by-2 tables. Associations were analysed using binary logistic regression. A total of 523 cancer patients (266 males, 257 females) were included in the final analysis and most had metastatic disease (83.2%). The median overall survival was 5.6 months. On multivariate binary logistic regression analysis, a high ECOG-PS remained independently associated with a low skeletal muscle index (p < 0.001), low skeletal muscle density (p < 0.05), and timed up and go test failure (p < 0.001). A high mGPS remained independently associated with a low skeletal muscle density (p < 0.05) and hand grip strength test failure (p < 0.01). A high BMI/WL grade remained independently associated with a low subcutaneous fat index (p < 0.05), low visceral obesity (p < 0.01), and low skeletal muscle density (p < 0.05). In conclusion, a high ECOG-PS and a high mGPS as outlined in the ECOG-PS/mGPS framework were consistently associated with poorer body composition and physical function in patients with advanced cancer