Tails from the Peak District: adjusted censored mixture models of EQ-5D health state utility values

Health state utility data generated using the EQ-5D instrument are typically right bounded at one with a substantial gap to the next set of observations, left bounded by some negative value, and are multi modal. These features present challenges to the estimation of the e¤ect of clinical and socioeconomic characteristics on health utilities. We present an adjusted censored model and then use this in a flexible, mixture modelling framework to address these issues. We demonstrate superior performance of this model compared to linear regression and Tobit censored regression using a dataset from repeated observations of patients with rheumatoid arthritis. We �nd that three latent classes are appropriate in estimating EQ-5D from function, pain and sociodemographic factors. Analysis of utility data should apply methods that recognise the distributional features of the data

Tails from the Peak District: adjusted censored mixture models of EQ-5D health state utility values

Health state utility data generated using the EQ-5D instrument are typically right bounded at one with a substantial gap to the next set of observations, left bounded by some negative value, and are multi modal. These features present challenges to the estimation of the e¤ect of clinical and socioeconomic characteristics on health utilities. We present an adjusted censored model and then use this in a flexible, mixture modelling framework to address these issues. We demonstrate superior performance of this model compared to linear regression and Tobit censored regression using a dataset from repeated observations of patients with rheumatoid arthritis. We �nd that three latent classes are appropriate in estimating EQ-5D from function, pain and sociodemographic factors. Analysis of utility data should apply methods that recognise the distributional features of the data

Tails from the Peak District: adjusted censored mixture models of EQ-5D health state utility values

Health state utility data generated using the EQ-5D instrument are typically right bounded at one with a substantial gap to the next set of observations, left bounded by some negative value, and are multi modal. These features present challenges to the estimation of the e¤ect of clinical and socioeconomic characteristics on health utilities. We present an adjusted censored model and then use this in a flexible, mixture modelling framework to address these issues. We demonstrate superior performance of this model compared to linear regression and Tobit censored regression using a dataset from repeated observations of patients with rheumatoid arthritis. We �nd that three latent classes are appropriate in estimating EQ-5D from function, pain and sociodemographic factors. Analysis of utility data should apply methods that recognise the distributional features of the data

Background information for Rajshahi City, Bangladesh

Land use / Population / Climate / Rain / Water resources / Households / Income / Social aspects / Water quality / Sanitation / Drainage / Waste management / Wastewater / Public health / Bangladesh / Rajshahi City

The groupoidal analogue Theta~ to Joyal's category Theta is a test category

We introduce the groupoidal analogue \tilde\Theta to Joyal's cell category \Theta and we prove that \tilde\Theta is a strict test category in the sense of Grothendieck. This implies that presheaves on \tilde\Theta model homotopy types in a canonical way. We also prove that the canonical functor from \Theta to \tilde\Theta is aspherical, again in the sense of Grothendieck. This allows us to compare weak equivalences of presheaves on \tilde\Theta to weak equivalences of presheaves on \Theta. Our proofs apply to other categories analogous to \Theta.Comment: 41 pages, v2: references added, Remark 7.3 added, v3: metadata update

Polarization of the ground state neutrons from the 7Li(d,n)8Be reaction

SIGLELD:D48236/84 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Exchange Leavitt path algebras and stable rank

We characterize those Leavitt path algebras which are exchange rings in terms of intrinsic properties of the graph and show that the values of the stable rank for these algebras are 1, 2 or ∞. Concrete criteria in terms of properties of the underlying graph are given for each case

Regeneration of activated carbon by photocatalysis using titanium dioxide

The adsorption of methylene blue onto two types of commercial activated carbons, a mesoporous type (Norit CA1) and microporous type (207C) was analysed. Powdered TiO2 was mixed with the carbon and added to the dye solution to determine the influence of the photocatalyst during the adsorption process. Equilibrium and kinetics experiments were done with and without any addition of photocatalytic titanium dioxide (TiO2). Changes in capacity, heterogeneity, and heat of adsorption were detected and related to changes in the quantity of TiO2 added by evaluating the equilibrium parameter from 13 isotherm models. The influence of TiO2 on the adsorption kinetics of the dye was correlated using simplified kinetic-type model as well as mass transfer parameters. Using a formal design of experiments approach responses such as the removal of the dye, variation of pH, external mass transfer rate (KF) and intraparticle rate constant (Ki) were evaluated. Results indicated that TiO2 increased the uptake of methylene blue onto CA1, increased Ki and CA1-TiO2 interactions had electrostatic nature. In contrast, TiO2 was seen to inhibit the equilibrium adsorption for 207C by reducing its capacity. The 207C-TiO2 interaction was attributed to a specific adsorption of TiO2 on the coconut-based adsorbent, as zeta potential and pH measurements seemed to suggest. The regeneration of activated carbon using UV-C/TiO2 heterogeneous photocatalysis in a novel bell photocatalytic reactor, and in a standard-type coiled-tube photoreactor was also studied. Initially, response surface methodology was applied to finding the optimum conditions for the mineralization of methylene blue in both reactors using methylene blue as model compound and TiO2 as photocatalyst performing direct photocatalytic decolourization. Methylene blue concentration, TiO2 concentration and pH were the variables under study. Complete mineralization of the dye was achieved in the coiled-tube reactor using 3.07 mg/L of methylene blue at pH 6.5 with 0.4149 g/L TiO2. The regeneration experiments in the coiled-tube photoreactor were done using One Variable at Time (OVAT) method. The effect of the mass of TiO2 was the only studied variable. The study indicated an increase in regeneration of CA1 and a decrease in the pH during the oxidation step at higher concentration of the photocatalyst. In the case of the regeneration of 207C, the addition of TiO2 lowered the regeneration and made the suspension more basic during the photocatalytic step. However these results were not statistically significant. Experiments using the bell photoreactor were performed applying the same response surface method used in direct photocatalytic decolourization (control). The variables under study were pH, concentration of dye-saturated carbon and TiO2 concentration. The regeneration percentage was the chosen response. Low regeneration percentages were achieved (maximum 63%), and significant differences (95% confidence interval) were found between the regeneration of the activated carbons, being higher in the case of powdered CA1 as compared with granular 207C