1,875,483 research outputs found

    How to deal with missing longitudinal data in cost of illness analysis in Alzheimer’s disease—suggestions from the GERAS observational study

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    BACKGROUND: Missing data are a common problem in prospective studies with a long follow-up, and the volume, pattern and reasons for missing data may be relevant when estimating the cost of illness. We aimed to evaluate the effects of different methods for dealing with missing longitudinal cost data and for costing caregiver time on total societal costs in Alzheimer's disease (AD). METHODS: GERAS is an 18-month observational study of costs associated with AD. Total societal costs included patient health and social care costs, and caregiver health and informal care costs. Missing data were classified as missing completely at random (MCAR), missing at random (MAR) or missing not at random (MNAR). Simulation datasets were generated from baseline data with 10-40 % missing total cost data for each missing data mechanism. Datasets were also simulated to reflect the missing cost data pattern at 18 months using MAR and MNAR assumptions. NaĂŻve and multiple imputation (MI) methods were applied to each dataset and results compared with complete GERAS 18-month cost data. Opportunity and replacement cost approaches were used for caregiver time, which was costed with and without supervision included and with time for working caregivers only being costed. RESULTS: Total costs were available for 99.4 % of 1497 patients at baseline. For MCAR datasets, naĂŻve methods performed as well as MI methods. For MAR, MI methods performed better than naĂŻve methods. All imputation approaches were poor for MNAR data. For all approaches, percentage bias increased with missing data volume. For datasets reflecting 18-month patterns, a combination of imputation methods provided more accurate cost estimates (e.g. bias: -1 % vs -6 % for single MI method), although different approaches to costing caregiver time had a greater impact on estimated costs (29-43 % increase over base case estimate). CONCLUSIONS: Methods used to impute missing cost data in AD will impact on accuracy of cost estimates although varying approaches to costing informal caregiver time has the greatest impact on total costs. Tailoring imputation methods to the reason for missing data will further our understanding of the best analytical approach for studies involving cost outcomes

    Possessive Expressions in Javanese

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    This study aims to describe the characteristics of Possessive Construction in Javanese and relations of expressions between Possessor (PR) and Possessum (PS). The source of data are texts in Javanese from Djaka Lodang Magazine Volume XXII, XXIV, XXIX year 2017 and Panjebar Semangat Magazine Volume 29, 19, and 20 from May until July 2018 which contains Possessive Constructions in Javanese also informant who is a native speaker of Javanese. The data are analyzed using Simak Method, with base Sadap technic and advance Simak-Bebas libat cakap technic and Catat technic, meanwhile technic for analyzing the data used are Agih Method to determine the Possessive Construction dan Padan Method to determine the relation between PR and PM elements. Javanese Possessive Constructions marked with clitics -e or ­-ne as possessive marker. The results show Javanese Possessive Constructions meaning exists at polymorphemic level, phrase level, and clause level. On polymorphemic level, possessive meaning expressed by nouns followed by enclitics persona pronoun. On Phrase level, possessive meaning expressed by noun which followed by noun persona and noun followed by noun. Persona pronoun acts as PR. Noun which acts as PR are (Ilahi), animal, plants and (concrete) noun. On clause level possessive meaning expressed by verb which occupy predicate (P). Noun occupying subject in clause recognized as possession (PM). In Javanese, it is found Possessive Construction which sates the relationship of proprietary in the form of; Possessive Construction in which PM elements is non-humane noun and PR elements is humane noun or persona pronoun, PM element is humane noun and PR element is humane (self-name) or persona pronoun, and PM element is non-living noun and PR element also non-living noun

    Survey of micrometeorological parameters within a forest canopy at Fort Polk, Louisiana, A

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    CER80-81WZS-FWL-WEM44.Includes bibliographical references (page 44).February 1982.A field investigation of micrometeorological parameters inside and above a forest canopy at Fort Polk, Louisiana, was conducted in conjunction with the Atmospheric Sciences Laboratory Dusty Infrared Test IIIA. The three orthogonal components of the wind, ory- and wet-bulb temperatures and total solar radiation were measured inside this forest canopy by means of an instrumented meteorological tower. In addition, turbulence inside the forest canopy was monitored by means of hot-wire anemometers. Tethersonde balloon sounding above the forest canopy was further performed. The meteorological data was reduced by means of three different statistical methods. Single sample period values, one-minute sample averages and sequential sample values were computed. The latter two methods led to the construction of time series which can readily be used to perform advanced statistical analyses. Totals of 27 h 29 min of meteorological tower data and 2 h 50 min of balloon data were reduced. The results are presented in tabular form in 1422 tables and partially displayed in 1795 figures under separate cover in view of their large volume. Selected samples of the results are, however, presented herein. The results supply a data base for analyses of airflow in a forest canopy. Suggestions for future work of significance for mission-oriented cases and for modeling of airflow in a forest canopy are outlined.Contract DAAG29-76-D-0100 conducted for the U.S. Army Atmospheric Sciences Laboratory, White Sands Missile Range

    Hydrochloric Acid Infusion for the Treatment of Metabolic Alkalosis in Surgical Intensive Care Unit Patients

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    Background: Older reports of use of hydrochloric acid (HCl) infusions for treatment of metabolic alkalosis document variable dosing strategies and risk. Objectives: This study sought to characterize use of HCl infusions in surgical intensive care unit patients for the treatment of metabolic alkalosis. Methods: This retrospective review included patients who received a HCl infusion for \u3e8 hours. The primary end point was to evaluate the utility of common acid-base equations for predicting HCl dose requirements. Secondary end points evaluated adverse effects, efficacy, duration of therapy, and total HCl dose needed to correct metabolic alkalosis. Data on demographics, potential causes of metabolic alkalosis, fluid volume, and duration of diuretics as well as laboratory data were collected. Results: A total of 30 patients were included, and the average HCl infusion rate was 10.5 ± 3.7 mEq/h for an average of 29 ± 14.6 hours. Metabolic alkalosis was primarily diuretic-induced (n = 26). Efficacy was characterized by reduction in the median total serum CO2 from 34 to 27 mM/L (P \u3c 0.001). The change in chloride ion deficit and change in apparent strong ion difference (SIDa) were not correlated with total HCl administered. There were no documented serious adverse effects related to HCl infusions. Conclusion: HCl was effective for treating metabolic alkalosis, and no serious adverse events were seen. In this clinical setting, the baseline chloride ion deficit and SIDa were not useful for prediction of total HCl dose requirement, and serial monitoring of response is recommended

    Towards greener horizontal-axis wind turbines: Analysis of carbon emissions, energy and costs at the early design stage

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    This paper describes the development of a quantitative analysis system as a platform for rapidly estimate energy, costs and carbon emission to facilitate the comparison of different wind turbine concept designs. This system aimed specifically at wind turbine manufacturing processes due to the fact that a large proportion of the environmental, costs and energy impacts would occur at this stage. The proposed method supports an initial assessment of multiple design concepts which allows the selection and development of a “greener” wind turbine. The developed system enables concept design of commercial wind turbine towers of hub heights between 44 and 135 m. The method supports an accurate estimation in regards to the dimension, energy consumed, maximum power output, costs and carbon emission in the early design phases of a wind turbine. As a result of the development, the proposed approach could potentially be used to minimise the carbon footprints of major engineering projects such as wind farms

    Buoyancy-induced convection of water-based nanofluids in differentially-heated horizontal Semi-Annuli

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    A two-phase model based on the double-diffusive approach is used to perform a numerical study on natural convection of water-based nanofluids in differentially- heated horizontal semi-annuli, assuming that Brownian diffusion and thermophoresis are the only slip mechanisms by which the solid phase can develop a significant relative velocity with respect to the liquid phase. The system of the governing equations of continuity, momentum, and energy for the nanofluid, and continuity for the nanoparticles, is solved by the way of a computational code which incorporates three empirical correlations for the evaluation of the effective thermal conductivity, the effective dynamic viscosity, and the thermophoretic diffusion coefficient, all based on a wide number of literature experimental data. The pressure-velocity coupling is handled through the SIMPLE-C algorithm. Numerical simulations are executed for three different nanofluids, using the diameter and the average volume fraction of the suspended nanoparticles, the cavity size, the average temperature, and the temperature difference imposed across the cavity, as independent variables. It is found that the impact of the nanoparticle dispersion into the base liquid increases remarkably with increasing the average temperature, whereas, by contrast, the other controlling parameters have moderate effects. Moreover, at temperatures of the order of room temperature or just higher, the heat transfer performance of the nanofluid is significantly affected by the choice of the solid phase material

    CHLOROBENZENE AS A DIFFERENTIATING SOLVENT FOR THE OSCILLOMETRIC TITRATION OF WEAK ORGANIC BASES

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    Water Absorption Properties of Cement Pastes: Experimental and Modelling Inspections

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    An intermingled fractal units’ model is shown in order to simulate pore microstructures as pore fraction and pore size distribution. This model is aimed at predicting capillary water absorption coefficient and sorptivity values in cement pastes. The results obtained are in good agreement with the experimental ones. For validating this model, a comparison with other procedures has been shown. It is possible to establish that the newly proposed method matches better with the experimental results. That is probably due to the fact that pore size distribution has been considered as a whole. Moreover, even though the proposed model is based on fractal base units, it is able to simulate and predict different properties as well as nonfractal porous microstructure
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