Validating a Multi-criteria decision analysis (MCDA) framework for health care decision making (abstract)

OBJECTIVES: When evaluating healthcare interventions, decision-makers are increasingly asked to consider multiple criteria to support their decision. The MCDA-based EVIDEM framework was developed to support this process. It includes a simple weight elicitation technique, designed to be easily applicable by a broad range of users. The objective of this study was to compare the EVIDEM technique with more traditional techniques. METHODS: An online questionnaire was developed comparing the EVIDEM technique with four alternative techniques including AHP, best/worst scaling, ranking and point-allocation. A convenience sample of 60 Dutch and Canadian students were asked to fill out the questionnaires as if they were sitting in an advisory committee for reimbursement/prioritization of healthcare interventions. They were asked to provide weights for 14 criteria using two techniques, and to provide feedback on ease of use and clarity of concepts of the different techniques. RESULTS: Results based on the first 30 responses show that EVIDEM is easy to understand and takes little time to complete, three minutes on average. Criteria weights derived using the EVIDEM technique and best/worst scaling are divergent. Comparing the rank order of criteria respondents gave using these two techniques; there is more resemblance in rank order of criteria weighted with the EVIDEM technique. Compared to AHP/ranking/point-allocation, EVIDEM takes less time to complete but is only preferred by 33% of decision-makers. AHP/ranking and point allocation were often described as clearer and more reflective of the respondents’ opinion. CONCLUSIONS: The simple technique is proposed as a starting point for users wishing to adapt the EVIDEM framework to their own context. Other techniques may be preferred and their impact on the MCDA value estimate generated by applying the framework is being explored. This project is part of a large collaborative work that includes developing and validating this framework to facilitate sound and efficient MCDA-applications

Generational Mass Splitting of Neutrinos in High Temperature SU(2)L⊗U(1)SU(2)_{\scriptscriptstyle{L}}\otimes U(1) Gauge Theory

We calculate the generational mass splitting of neutrinos in high temperature $SU(2)_{\scriptscriptstyle{L}}\otimes U(1)$ gauge theory when the temperature is above $250$ GeV and the gauge symmetry is restored. We consider the case of neutrinos that are massless at tree level as well as the case of neutrinos with tree-level mass and large mixing.Comment: 12 Pages, JHU-TIPAC-940008/INFNCA-TH-94-

Quasilocality of joining/splitting strings from coherent states

Using the coherent state formalism we calculate matrix elements of the one-loop non-planar dilatation operator of ${\cal N}=4$ SYM between operators dual to folded Frolov-Tseytlin strings and observe a curious scaling behavior. We comment on the {\it qualitative} similarity of our matrix elements to the interaction vertex of a string field theory. In addition, we present a solvable toy model for string splitting and joining. The scaling behaviour of the matrix elements suggests that the contribution to the genus one energy shift coming from semi-classical string splitting and joining is small.Comment: 17 pages, 7 figures in 11 file

The use of multi-criteria decision methods in health care:Which method is most suitable for healthy and cognitively impaired population?

OBJECTIVES: To select the best multi-criteria decision making method for use with cognitively impaired patients. 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. After using the methods to establish preferences for treatment, subjects were asked to judge the overall difficulty of the techniques on 1–10 score, and answer questions regarding clarity of explanation of method, difficulty in answering questions, understanding method in relation to goal, and use of the method in health care situations. Subjects were interviewed either once (n = 14) or twice (n = 14) (Only the results of the first measurement are presented)RESULTS: In the overall rating of methods CA scored best (mean score 3.65), followed by SMART (3.70), AHP (4.00), SWING (4.40) and KTA (4.67). CA also scored best on verbal/written explanation, understanding of method in relation to goal second and usefulness in health care situations, and scored second place on difficulty in answering questions. In the impaired population, AHP was rated best on the overall difficulty score.CONCLUSIONS: In this pilot study, conjoint analysis was the most preferred method of preference elicitation. Our main concern regarding CA is the time it takes to fill out a CA questionnaire and the fact that data analysis is most complicated of all methods included. Another concern regarding the use of multicriteria methods needing further study is the rate of rank-reversal between methods in the cognitively impaired population

Anomalous dimension and local charges

AdS space is the universal covering of a hyperboloid. We consider the action of the deck transformations on a classical string worldsheet in $AdS_5\times S^5$. We argue that these transformations are generated by an infinite linear combination of the local conserved charges. We conjecture that a similar relation holds for the corresponding operators on the field theory side. This would be a generalization of the recent field theory results showing that the one loop anomalous dimension is proportional to the Casimir operator in the representation of the Yangian algebra.Comment: 10 pages, LaTeX; v2: added explanations, reference

Threshold Corrections and Gauge Symmetry in Twisted Superstring Models

Threshold corrections to the running of gauge couplings are calculated for superstring models with free complex world sheet fermions. For two N=1 $SU(2)\times U(1)^5$ models, the threshold corrections lead to a small increase in the unification scale. Examples are given to illustrate how a given particle spectrum can be described by models with different boundary conditions on the internal fermions. We also discuss how complex twisted fermions can enhance the symmetry group of an N=4 $SU(3)\times U(1)\times U(1)$ model to the gauge group $SU(3)\times SU(2)\times U(1)$. It is then shown how a mixing angle analogous to the Weinberg angle depends on the boundary conditions of the internal fermions.Comment: easier to Tex version, figures to be sent separatel

Scalar Solitons on the Fuzzy Sphere

We study scalar solitons on the fuzzy sphere at arbitrary radius and noncommutativity. We prove that no solitons exist if the radius is below a certain value. Solitons do exist for radii above a critical value which depends on the noncommutativity parameter. We construct a family of soliton solutions which are stable and which converge to solitons on the Moyal plane in an appropriate limit. These solutions are rotationally symmetric about an axis and have no allowed deformations. Solitons that describe multiple lumps on the fuzzy sphere can also be constructed but they are not stable.Comment: 24 pages, 2 figures, typo corrected and stylistic changes. v3: reference adde

A Relation Between Approaches to Integrability in Superconformal Yang-Mills Theory

We make contact between the infinite-dimensional non-local symmetry of the typeIIB superstring on AdS5xS5 worldsheet theory and a non-abelian infinite-dimensional symmetry algebra for the weakly coupled superconformal gauge theory. We explain why the planar limit of the one-loop dilatation operator is the Hamiltonian of a spin chain, and show that it commutes with the g*2 N = 0 limit of the non-abelian charges.Comment: 19 pages, harvma

An exploratory study examining the relationship between performance status and systemic inflammation frameworks and cytokine profiles in patients with advanced cancer

The role of cytokines in the systemic inflammatory response (SIR) is now well established. This is in keeping with the role of the SIR in tumorigenesis, malignant spread, and the development of cachexia. However, the relationship between performance status/systemic inflammation frameworks and cytokine profiles is not clear. The aim of the present study was to examine the relationship between the Eastern cooperative oncology group performance status/modified Glasgow prognostic score (ECOG-PS/mGPS) and cooperative oncology group performance status/neutrophil platelet score (ECOG-PS/NPS) frameworks and their cytokine profile in patients with advanced cancer.This was a retrospective interrogation of data already collected as part of a recent clinical trial (NCT00676936). The relationship between the independent variables (ECOG-PS/mGPS and ECOG-PS/NPS frameworks), and dependent variables (cytokine levels) was examined using independent Mann-Whitney U and Kruskal Wallis tests where appropriate.Of the 40 patients included in final analysis the majority had evidence of an SIR assessed by mGPS (78%) or NPS (53%). All patients died on follow-up and the median survival was 91 days (4-933 days). With increasing ECOG-PS there was a higher median value of Interleukin 6 (IL-6, P = .016) and C-reactive protein (CRP, P < .01) and lower albumin (P < .01) and poorer survival (P < .001). With increasing mGPS there was a higher median value of IL-6 (P = .016), Macrophage migration inhibitory factor (MIF, P = .010), erythrocyte sedimentation rate (ESR, P < .01) and poorer survival (P < .01). With increasing NPS there was a higher median value of TGF-β (P < .001) and C-reactive protein (P = .020) and poor survival (P = .001). When those patients with an ECOG-PS 0/1 and mGPS0 were compared with those patients with an ECOG-PS 2 and mGPS2 there was a higher median value of IL-6 (P = .017) and poorer survival (P < .001). When those patients with an ECOG-PS 0/1 and NPS0 were compared with those patients with an ECOG-PS 2 and NPS1/2 there was a higher median value of IL-6 (P = .002), TGF-β (P < .001) and poorer survival (P < .01).In patients with advanced cancer IL-6 was associated with the ECOG-PS/mGPS and ECOG-PS/NPS frameworks and survival in patients with advanced cancer. Therefore, the present work provides supporting evidence that agents targeting IL-6 are worthy of further exploration

Decoupling limits of N=4 super Yang-Mills on R x S^3

We find new decoupling limits of N=4 super Yang-Mills (SYM) on R x S^3 with gauge group SU(N). These decoupling limits lead to decoupled theories that are much simpler than the full N=4 SYM but still contain many of its interesting features. The decoupling limits correspond to being in a near-critical region, near a point with zero temperature and critical chemical potentials. The new decoupling limits are found by generalizing the limits of hep-th/0605234 to include not only the chemical potentials for the SU(4) R-symmetry of N=4 SYM but also the chemical potentials corresponding to the SO(4) symmetry. In the decoupled theories it is possible to take a strong coupling limit in a controllable manner since the full effective Hamiltonian is known. For planar N=4 SYM on R x S^3 all the decoupled theories correspond to fully integrable spin chains. We study the thermodynamics of the decoupled theories and find the Hagedorn temperature for small and large values of the effective coupling. We find an alternative formulation of the decoupling limits in the microcanonical ensemble. This leads to a characterization of certain regimes of weakly coupled N=4 SYM in which there are string-like states. Finally, we find a similar decoupling limit for pure Yang-Mills theory, which for the planar limit leads to a fully integrable decoupled theory.Comment: 48 pages, 1 figure; added references, published versio