Predicting missing quality of life data that were later recovered : an empirical comparison of approaches

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Combinatorial realizations of crystals via torus actions on quiver varieties

Consider Kashiwara's crystal associated to a highest weight representation of a symmetric Kac-Moody algebra. There is a geometric realization of this object using Nakajima's quiver varieties, but in many particular cases it can also be realized by elementary combinatorial methods. Here we propose a framework for extracting combinatorial realizations from the geometric picture: We construct certain torus actions on the quiver varieties and use Morse theory to index the irreducible components by connected components of the subvariety of torus fixed points. We then discuss the case of affine sl(n). There the fixed point components are just points, and are naturally indexed by multi-partitions. There is some choice in our construction, leading to a family of combinatorial models for each highest weight crystal. Applying this construction to the crystal of the fundamental representation recovers a family of combinatorial realizations recently constructed by Fayers. This gives a more conceptual proof of Fayers' result as well as a generalization to higher level. We also discuss a relationship with Nakajima's monomial crystal.Comment: 23 pages, v2: added Section 8 on monomial crystals and some references; v3: many small correction

Trajectories of self-rated health in people with diabetes: Associations with functioning in a prospective community sample

© 2013 Schmitz et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Background: Self-rated health (SRH) is a single-item measure that is one of the most widely used measures of general health in population health research. Relatively little is known about changes and the trajectories of SRH in people with chronic medical conditions. The aims of the present study were to identify and describe longitudinal trajectories of self-rated health (SRH) status in people with diabetes. Methods: A prospective community study was carried out between 2008 and 2011. SRH was assessed at baseline and yearly at follow-ups (n=1288). Analysis was carried out through trajectory modeling. The trajectory groups were subsequently compared at 4 years follow-up with respect to functioning. Results: Four distinct trajectories of SRH were identified: 1) 72.2% of the participants were assigned to a persistently good SRH trajectory; 2) 10.1% were assigned to a persistently poor SRH trajectory; 3) mean SRH scores changed from good to poor for one group (7.3%); while 4) mean SRH scores changed from poor to medium/good for another group (10.4%). Those with a persistently poor perception of health status were at higher risk for poor functioning at 4 years follow-up than those whose SRH scores decreased from good to poor. Conclusions: SRH is an important predictor for poor functioning in diabetes, but the trajectory of SRH seems to be even more important. Health professionals should pay attention to not only SRH per se, but also changes in SRH over time.This work was supported by Operating Grant MOP-84574 from the Canadian Institutes of Health Research (CIHR). GG was supported by a doctoral fellowship from the CIHR. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Quality of life on the views of older family carers of people with dementia

Older family carers of people with dementia represent an increasing but overlooked population of family carers. This research aimed to explore how these individuals make sense of their own quality of life and to identify the factors that enhance or compromise this. Four focus groups were conducted in 2014 with 19 older family carers in community-based support groups in Nottinghamshire, United Kingdom. Data was transcribed verbatim and analysed using Interpretative Phenomenological Analysis. Thirty-three subthemes emerged and were collated into three superordinate themes: 1) aspects of care and caregiving, 2) feelings and concerns, and 3) satisfaction with life and caregiving. This study identified a broad range of aspects that are of particular importance to the QoL of older family carers of people with dementia. These findings are expected to inform future research as well as health and social care providers with the aim of improving life quality for this population

Splitting technique for analytical modelling of two-phase multicomponent flow in porous media

In this paper we discuss one-dimensional models for two-phase Enhanced Oil Recovery (EOR) floods (oil displacement by gases, polymers, carbonized water, hot water, etc.). The main result presented here is the splitting of the EOR mathematical model into thermodynamical and hydrodynamical parts. The introduction of a potential associated with one of the conservation laws and its use as a new independent coordinate reduces the number of equations by one. The (n) × (n) conservation law model for two-phase n-component EOR flows in new coordinates is transformed into a reduced (n − 1) × (n − 1) auxiliary system containing just thermodynamical variables (equilibrium fractions of components, sorption isotherms) and one lifting equation containing just hydrodynamical parameters (phase relative permeabilities and viscosities). The algorithm to solve analytically the problem includes solution of the reduced auxiliary problem, solution of one lifting hyperbolic equation and inversion of the coordinate transformation. The splitting allows proving the independence of phase transitions occurring during displacement of phase relative permeabilities and viscosities. For example, the minimum miscibility pressure (MMP) and transitional tie lines are independent of relative permeabilities and phases viscosities. Relative motion of polymer, surfactant and fresh water slugs depends on sorption isotherms only. Therefore, MMP for gasflood or minimum fresh water slug size providing isolation of polymer/surfactant from incompatible formation water for chemical flooding can be calculated from the reduced auxiliary system. Reduction of the number of equations allows the generation of new analytical models for EOR. The analytical model for displacement of oil by a polymer slug with water drive is presented.Adolfo P. Pires, Pavel G. Bedrikovetsky, Alexander A. Shapir

Relationship between health-related quality of life and respiratory health status among coal-based sponge iron plant workers in Barjora, India

Background: Many coal-based sponge iron plant workers have poor health-related quality of life in general, and specifically a poor respiratory health status. However, the relationship between their health-related quality of life and respiratory health status is unknown. Aim: This study investigated the relationship between health related quality of life, measured using the EuroQol- 5D (EQ5D), and respiratory health status, measured using the St. George’s Respiratory Questionnaire (SGRQ), among coal-based sponge iron plant workers in Barjora, India. Method: A cross-sectional study was conducted among coalbased sponge iron plant workers in Barjora, and complete data were available on 252 participants. Spearman’s rank correlation coefficients were reported to show the strength of relationship between health-related quality of life and respiratory health status. Results and conclusion: Significant correlations were found between all EQ5D dimensions/visual analogue scale (VAS) and all SGRQ scores except between EQ5D-VAS and SGRQ-activity. A range of correlations was found. They were moderate between EQ5D-anxiety/depression and SGRQ-symptom, EQ5D-VAS and SGRQ-symptom, and EQ5D-anxiety/depression and SGRQ-total, but weak between all the other factors

Validation of the Consensus-Definition for Cancer Cachexia and evaluation of a classification model—a study based on data from an international multicentre project (EPCRC-CSA)

A cancer cachexia classification into stages is warranted in order to guide treatment decisions and clinical trial inclusion. Weight loss and BMI clearly discriminate between non-cachectic and cachectic patients both with regards to all the domains (Intake, Catabolism and Function) and survival. The precachexia stage might be better defined by additional factors in order to be discriminativ

Trends in UK cancer trials: results from the UK Coordinating Committee for Cancer Research National Register of Cancer Trials

We aimed to study trends in the design and conduct of randomised controlled trials (RCTs) in cancer in the UK, using the UK Coordinating Committee for Cancer Research (UKCCCR) National Register of Cancer Trials (NRCT). We conducted a descriptive survey of 520 UK RCTs in cancer that were registered on the UKCCCR NRCT. All trials had been initiated between 1971 and 2000. Trials on the NRCT have been conducted in a wide variety of cancer types, but with a third in breast (22%) or lung cancer (11%). They have largely been funded by the UK public and charity sectors. Overall, there has been a sustained rise in the total numbers of patients entering UK cancer trials over time with a trend towards larger, multicentre trials, greater recruitment targets and a marked reduction in the average time taken to complete trials. Trends in the design and conduct of noncommercial cancer RCTs from 1971 to 2000 are encouraging. It will be interesting to see how they develop in light of the implementation of recent national initiatives regarding cancer clinical trials in the UK