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Various Estimates (various + estimate)

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Medical Sciences	50%

Selected Abstracts

Global atmospheric energetics from NCEP,Reanalysis 2 and ECMWF,ERA40 Reanalysis

INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 2 2009
Carlos A. F. Marques
Abstract The global atmospheric energy cycle is estimated on an annual basis using Reanalysis 2 data from the National Centers for Environmental Prediction and National Center for Atmospheric Research (NCEP/NCAR), and ERA 40 Reanalyses from the European Centre for Medium-Range Weather Forecasts (ECMWF) for the period 1979,2001. A formalism to avoid belowground data on pressure levels intercepted by topography is adopted. No appreciable differences were found between the two datasets from the energetics point of view. The so-called ,, and v·grad z formulations were both used for the conversions from zonal available potential energy into zonal kinetic energy (CZ) and from eddy available potential energy into eddy kinetic energy (CE). Results with both formulations are comparable only when using the formalism preventing belowground data to enter into the computations. Atmospheric energetics are also computed using ECMWF Reanalyses for the period 1958,1978. A significant increase was found in the eddy kinetic and eddy available potential energies from the early period to the later period, likely related to the assimilation in the reanalyses of satellite data after 1979. The conversion rate, CZ, was found to change its sign throughout the years. The atmospheric energy cycle using the ECMWF Reanalyses data is compared with five previous estimates. Differences in the direction of the conversion rate, CZ, between the various estimates may be explained by the different time periods chosen for averaging. Owing to the omission of belowground data, the conversion from zonal available potential energy into eddy available potential energy (CA) was somewhat smaller in ECMWF Reanalyses than in the previous estimates. Despite those differences, an overall agreement may be found between the various estimates for the atmospheric energy cycle. Copyright © 2008 Royal Meteorological Society [source]

Effect of various estimates of renal function on prediction of vancomycin concentration by the population mean and Bayesian methods

JOURNAL OF CLINICAL PHARMACY & THERAPEUTICS, Issue 4 2009
Y. Tsuji BSc
Summary Objective:, Renal function was estimated in 129 elderly patients with methicillin-resistant Staphylococcus aureus (MRSA) who were treated with vancomycin (VCM). The estimation was performed by substituting serum creatinine (SCR) measured enzymatically and a value converted using the Jaffe method into the Cockcroft-Gault and Modification of Diet in Renal Disease (MDRD) equations. The serum trough level was predicted from three estimates of renal function by the population mean (PM) and Bayesian methods and the predictability was assessed. Methods:, Two-compartment model-based Japanese population parameters for VCM were used, and the mean prediction error (ME) and root mean squared error (RMSE) were calculated as indices of bias and accuracy, respectively, for predictions by the PM and Bayesian methods. Results:, The PM method gave the highest correlation with the measured value using the estimate of renal function obtained by substituting the Jaffe-converted SCR into the Cockcroft-Gault equation. There was no positive or negative bias in the ME and the value was significantly smaller than for other predicted data (P < 0·05). RMSE was also the smallest, indicating that this method increases the predictability of the serum VCM trough level. While, ME showed a negative bias for all values predicted by the Bayesian method, both the ME and RMSE were very small. Conclusion:, In the application of the PM method for VCM treatment of elderly patients with MRSA, substitution of SCR based on the Jaffe method into the Cockcroft-Gault equation increases the predictability of the serum VCM trough level. The Bayesian method predicted the serum VCM trough level with high accuracy using any of the estimates of renal function. [source]

A comparison of measures of disproportionality for signal detection in spontaneous reporting systems for adverse drug reactions

PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 1 2002
Eugéne P. van Puijenbroek
Abstract Purpose A continuous systematic review of all combinations of drugs and suspected adverse reactions (ADRs) reported to a spontaneous reporting system, is necessary to optimize signal detection. To focus attention of human reviewers, quantitative procedures can be used to sift data in different ways. In various centres, different measures are used to quantify the extent to which an ADR is reported disproportionally to a certain drug compared to the generality of the database. The objective of this study is to examine the level of concordance of the various estimates to the measure used by the WHO Collaborating Centre for International ADR monitoring, the information component (IC), when applied to the dataset of the Netherlands Pharmacovigilance Foundation Lareb. Methods The Reporting Odds Ratio,1.96 standard errors (SE), proportional reporting ratio,1.96 SE, Yule's Q,1.96,SE, the Poisson probability and Chi-square test of all 17,330 combinations were compared with the IC minus 2 standard deviations. Additionally, the concordance of the various tests, in respect to the number of reports per combination, was examined. Results In general, sensitivity was high in respect to the reference measure when a combination of point- and precision estimate was used. The concordance increased dramatically when the number of reports per combination increased. Conclusion This study shows that the different measures used are broadly comparable when four or more cases per combination have been collected. Copyright © 2001 John Wiley & Sons, Ltd. [source]

ASSESSING EUROPEAN CENTRAL BANK'S CREDIBILITY DURING THE FIRST YEARS OF THE EUROSYSTEM: A BAYESIAN EMPIRICAL INVESTIGATION

THE MANCHESTER SCHOOL, Issue 5 2010
GIANNI AMISANO
In this paper we extend Svenssons (CEPR Discussion Paper 940, April 1994) ,simplest test' of inflation target credibility inside a Bayesian econometric framework and obtain various estimates of the European Central Bank's monetary policy credibility. Overall, our empirical evidence suggests that the strategy followed by the European Central Bank was successful in building a satisfactory degree of reputation. However, we find some significant credibility reversals concerning both anti-inflationary and anti-deflationary credibility. These reversals, in turn, are closely related to the evolution of the cyclical macroeconomic conditions in the euro area. [source]