Use of Prediction Methods to Assess Laboratory Bias and Mean Values Associated with an Interlaboratory Study for Method Validation and/or Proficiency Testing

2014 ◽  
Vol 97 (2) ◽  
pp. 624-629 ◽  
Author(s):  
Foster D McClure ◽  
Jung K Lee
Keyword(s):  
Random Variables ◽  
Least Square ◽  
Best Linear Unbiased Predictor ◽  
Least Square Estimator ◽  
Mean Values ◽  
Interlaboratory Studies ◽  
Repeatability And Reproducibility ◽  
Best Linear Unbiased ◽  
The Mean ◽  
The Individual

Abstract Two methods of prediction of random variables, best predictor (BP) and best linear unbiased predictor (BLUP), are discussed as potential statistical methods to predict laboratory true mean and bias values using the sample laboratory mean (yi) from interlaboratory studies. The predictions developed here require that the interlaboratory and/or proficiency study be designed and conducted in a manner consistent with the assumptions of a one-way completely randomized model (CRM). Under the CRM the individual laboratory true mean and bias are not parameters but are defined to be random variables that are unobservable and considered as realized values that cannot be estimated but can be predicted using methods of “prediction.” The BP method is applicable when all salient parameters are known, e.g., the consensus true overall mean (μ) and repeatability and reproducibility components (σr2 and σR2), while the BLUP method is useful when σ2r and σR2 are known, but μ is estimated by the generalized least square estimator. Although the derivations of predictors are obtained by minimizing the mean-square error under the CRM assumptions, the predictors are the expected laboratory true mean and bias given the sample laboratory mean, i.e., conditional expectation.

scholarly journals Effects of food and sucralfate on a single oral dose of 500 milligrams of levofloxacin in healthy subjects.

1997 ◽  
Vol 41 (10) ◽  
pp. 2196-2200 ◽  
Author(s):  
L J Lee ◽  
B Hafkin ◽  
I D Lee ◽  
J Hoh ◽  
R Dix
Keyword(s):  
Oral Dose ◽  
Healthy Subjects ◽  
High Fat ◽  
Time Curve ◽  
Mean Values ◽  
Treatment Groups ◽  
The Mean ◽  
The Individual ◽  
Individual Profiles ◽  
Fat Meal

The effects of food and sucralfate on the pharmacokinetics of levofloxacin following the administration of a single 500-mg oral dose were investigated in a randomized, three-way crossover study with young healthy subjects (12 males and 12 females). Levofloxacin was administered under three conditions: fasting, fed (immediately after a standardized high-fat breakfast), and fasting with sucralfate given 2 h following the administration of levofloxacin. The concentrations of levofloxacin in plasma and urine were determined by high-pressure liquid chromatography. By noncompartmental methods, the maximum concentration of drug in serum (Cmax), the time to Cmax (Tmax), the area under the concentration-time curve (AUC), half-life (t1/2), clearance (CL/F), renal clearance (CLR), and cumulative amount of levofloxacin in urine (Ae) were estimated. The individual profiles of the drug concentration in plasma showed little difference among the three treatments. The only consistent effect of the coadministration of levofloxacin with a high-fat meal for most subjects was that levofloxacin absorption was delayed and Cmax was slightly reduced (Tmax, 1.0 and 2.0 h for fasting and fed conditions, respectively [P = 0.002]; Cmax, 5.9 +/- 1.3 and 5.1 +/- 0.9 microg/ml [90% confidence interval = 0.79 to 0.94] for fasting and fed conditions, respectively). Sucralfate, which was administered 2 h after the administration of levofloxacin, appeared to have no effect on levofloxacin's disposition compared with that under the fasting condition. Mean values of Cmax and AUC from time zero to infinity were 6.7 +/- 3.2 microg/ml and 47.9 +/- 8.4 microg x h/ml, respectively, following the administration of sucralfate compared to values of 5.9 +/- 1.3 microg/ml and 50.5 +/- 8.1 microg x h/ml, respectively, under fasting conditions. The mean t1/2, CL/F, CLR, and Ae values were similar among all three treatment groups. In conclusion, the absorption of levofloxacin was slightly delayed by food, although the overall bioavailability of levofloxacin following a high-fat meal was not altered. Finally, sucralfate did not alter the disposition of levofloxacin when sucralfate was given 2 h after the administration of the antibacterial agent, thus preventing a potential drug-drug interaction.

scholarly journals Genetic homozygosity as a marker of smoking dependency

Genetika ◽  
2020 ◽  
Vol 52 (3) ◽  
pp. 1009-1019
Author(s):  
Slavko Brankovic ◽  
Dejan Nikolic ◽  
Dragoslav Marinkovic ◽  
Suzana Cvjeticanin
Keyword(s):  
Cross Sectional Study ◽  
Male Gender ◽  
Sectional Study ◽  
Cross Sectional ◽  
Male And Female ◽  
Mean Values ◽  
Individual Variations ◽  
Significant Difference ◽  
The Mean ◽  
The Individual

The aim of our study was to evaluate the morphogenetic variability as a marker of smoking dependency in adult smokers versus controls and to investigate the presence and the degree of morphogenetic variability difference between male and female smokers versus same gender controls. The cross-sectional study evaluated 241 smokers and 185 nonsmoker individuals as controls. We analyzed 17 homozygous recessive characteristics (HRC). There was a significant difference in the individual variations of 17 HRCs between the controls and smokers (??2=61.400, p<0.001; for females ??2=79.440, p<0.001; for males ??2=84.972, p<0.001). The mean values of HRCs significantly differed between smokers and controls (MV?SEM(Controls) -4.79?0.13, MV?SEM(Smokers) -5.70?0.12; p<0.001). For males, presence of 6/17 (35.29% genetic homozygosity) HRCs (OR=6.12) was to the certain degree predictor for smoking dependency. Higher degree of genetic homozygosity, changed variability and male gender, might be some among potential numerous factors that could have impact on smoking development and dependence.

scholarly journals Inter-Laboratory Correlation Exercise with Portable Emissions Measurement Systems (PEMS) on Chassis Dynamometers

2018 ◽  
Vol 8 (11) ◽  
pp. 2275 ◽  
Author(s):  
Barouch Giechaskiel ◽  
Simone Casadei ◽  
Michele Mazzini ◽  
Mario Sammarco ◽  
Gisella Montabone ◽  
...  
Keyword(s):  
Particle Number ◽  
Laboratory Method ◽  
Measurement Systems ◽  
Type Approval ◽  
Light Duty ◽  
Repeatability And Reproducibility ◽  
Light Duty Vehicle ◽  
The Mean ◽  
Mean Differences ◽  
The Individual

The recently introduced Real Driving Emissions (RDE) light-duty vehicle emissions regulation requires testing with Portable Emissions Measurement Systems (PEMS) during type approval and in-service conformity. The studies on the accuracy of PEMS today are limited. An inter-laboratory correlation exercise with PEMS took place in Italy in 2017. Eight laboratories measured exhaust emissions from a Golden Euro 6 gasoline vehicle with a Golden PEMS installed in it, along with the individual lab’s own PEMS, following the regulated laboratory method (bags from the dilution tunnel). The data of the exercise were used to estimate the repeatability and reproducibility of the methodology with PEMS. The statistical analysis estimated reproducibility of 2.9% (bags) to 5.5% (lab PEMS) for CO2, 20–25% for CO (all methods), 23–31% for NOx (all methods), and 29% (tunnel, Golden PEMS) to 39% (lab PEMS) for particle number. The mean differences of the PEMS to the regulated method were ±1.5 g/km (or ±1%) for CO2, <16 mg/km (or <5%) for CO, <4 mg/km (or <11%) for NOx and 1 × 1011 particles/km (40%) for particle number. The results of this study confirm the satisfactory performance of PEMS and the permissible tolerances introduced in RDE regulation.

scholarly journals On phenomena relating to the spectra of hydrogen and helium

1916 ◽  
Vol 93 (646) ◽  
pp. 27-28
Keyword(s):  
Accurate Determination ◽  
Principal Series ◽  
Black Body ◽  
Black Body Radiation ◽  
Balmer Series ◽  
Mean Values ◽  
Carbon Arc ◽  
The Mean ◽  
The Individual

In a previous paper the structure of broadened spectrum lines was investigated by a method involving the use of a neutral-tinted wedge as an accessory to the spectroscope. The present communication deals with a method for the accurate determination of the photographic intensities of spectrum lines and the reduction of such intensities to absolute values by comparison with the continuous black-body radiation of the carbon arc. These methods have been applied to a study of the relative intensity distribution in the spectra of helium and hydrogen under different conditions of excitation. It has been found that under certain specified conditions there is a transfer of energy from the longer to the shorter wave-lengths in any given series, and that, under such conditions, the associated series, and in particular the Diffuse series, are relatively enhanced at the expense of the Principal series. It has also been found that the distribution of intensity found in certain celestial spectra can be approximately reproduced in the laboratory. In any attempt to interpret the phenomena observed in connection with the Balmer series of hydrogen, it is necessary to know the particular type to which this series belongs. In order to decide this point a study has been made of the separations of the components of lines of the Balmer series of hydrogen, and the mean values of the separations of the doublets constituting the lines H a and H β have been found to be respectively 0.132 Å.U. and 0.033 Å.U. These values are consistent with the separations appropriate to a Principal series, and the first is in precise agreement with the value deduced by Buisson and Fabry. These results have been obtained by crossing a Lummer Gehrcke plate with the neutral wedge, and submitting the contours obtained to mathematical analysis, by means of which the distribution of intensity in the individual components, and the separation of the components, can be determined.

scholarly journals On deterministic approximation of Markov processes by ordinary differential equations

1998 ◽  
Vol 4 (2) ◽  
pp. 99-114 ◽  
Author(s):  
L. I. Rozonoer
Keyword(s):  
Differential Equations ◽  
Markov Model ◽  
Ordinary Differential Equations ◽  
Chemical Reaction ◽  
Markov Processes ◽  
Random Variables ◽  
Mean Values ◽  
Multidimensional Lattice ◽  
The Mean

For a class of Markov processes on the integer multidimensional lattice, it is shown that the evolution of the mean values of some random variables can be approximated by ordinary differential equations. To illustrate the approach, a Markov model of a chemical reaction is considered

scholarly journals Determination of Sex Ratio In Bovine Semen Using SYBR Green Real-Time PCR

2022 ◽  
Author(s):  
Vemula Harshini ◽  
S.M.K. Karthickeyan ◽  
K.G P. Kumarasamy ◽  
Tirumurugaan ◽  
C. Jeevan
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Sybr Green ◽  
Pcr Assay ◽  
Mean Values ◽  
Bovine Semen ◽  
Routine Basis ◽  
Repeatability And Reproducibility ◽  
The Mean

Abstract A SYBR green real-time PCR assay was developed to find out the sex skewness in bovine sex-sorted semen samples. The qPCR assay of PLP and SRY genes revealed the mean values of X- and Y-bearing spermatozoa as 50.24 ± 0.65 and 49.75 ± 0.62 per cent in unsorted, and 91.80 ± 0.79 and 8.20 ± 0.73 per cent in X-enriched semen samples respectively.. The amplification efficiencies of the PLP and SRY primers were 99.25 and 98.03 per cent respectively. The method was validated by a series of repeatability and reproducibility assays which revealed low co-efficients of variations as 2.19 and 3.12 per cent respectively Thus becoming a reliable and inexpensive tool to evaluate the sorted semen on routine basis and validation of other sperm sexing technologies.

scholarly journals Assessment of Tug of War pullers competition intensity and physiological response at the 2019 European Championship

Retos ◽  
2021 ◽  
Vol 44 ◽  
pp. 357-363
Author(s):  
Arkaitz Castañeda-Babarro ◽  
Borja Gutiérrez Santamaría ◽  
Aitor Coca ◽  
Julio Calleja-González ◽  
Ruth Cayero
Keyword(s):  
Blood Lactate ◽  
Anaerobic Threshold ◽  
Perceived Exertion ◽  
Rating Of Perceived Exertion ◽  
Global Rating ◽  
Mean Values ◽  
Performance Factors ◽  
Individual Anaerobic Threshold ◽  
The Mean ◽  
The Individual

Tug of war (TOW) involves 2 teams of eight people, pulling against each other on a rope. The main goal of TOW is to pull the opposing team towards a centre line over a distance of 4 m. The measurement of physiological parameters is key to understanding the demands of an activity and to identifying its limiting performance factors. The main aim of this study was to evaluate the intensity and effort demands of TOW pullers during competition, as follows: Data were collected from 7 male pullers (Height: 175.14±4.85; Body Mass: 77.39±3.92; Age: 39.86±11.68; %Fat: 17.56±5.21; VO2max: 44.24±8.38) in the 560 kg category. The blood lactate concentrations (LAC) were assessed before and at the end of each pull, and the global rating of perceived exertion (RPE) at the end of the pulls. The following week, pullers performed a graded exercise test (GXT). Heart rate, LAC and RPE were assessed before, during and at the end of the GXT to calculate the individual anaerobic threshold. The mean blood lactate concentrations recorded at the end of the pulls (6±1.9 mmol/l) were 32% higher than the mean values recorded for the individual anaerobic threshold intensity (4.1±0.5 mmol/l). For their part, the mean RPE values of athletes after the pulls (6±1.5 mmol/l) were 21% lower than those obtained for intensity of the individual anaerobic threshold (7.6±0.8 mmol/l). The intensity and effort response are greater and kept above the anaerobic threshold during the competition in TOW pullers. Resumen. Tug of war (TOW) involucra a 2 equipos de ocho personas, tirando una contra la otra con una cuerda. El objetivo principal es llevar al equipo contrario hacia una línea central a una distancia de 4 m. La medición de parámetros fisiológicos es clave para comprender las demandas de una actividad y para identificar sus factores limitantes de rendimiento. El objetivo principal de este estudio fue evaluar la intensidad y las demandas de esfuerzo de los tiradores de TOW durante la competición. 7 tiradores masculinos (altura: 175,14 ± 4,85; masa corporal: 77,39 ± 3,92; edad: 39,86 ± 11,68; % de grasa: 17,56 ± 5,21; VO2max: 44,24 ± 8,38) en la categoría de 560 kg. Se evaluaron concentraciones de lactato (LAC) antes y después de cada tirada, y el esfuerzo percibido (RPE) al final. La siguiente semana, los tiradores realizaron una prueba de esfuerzo (GXT). La FC, LAC y RPE se evaluaron antes, durante y después del GXT para calcular el umbral anaeróbico individual. Las concentraciones de LAC registradas medios registrados para la intensidad del umbral anaeróbico individual (VT2) (4,1 ± 0,5 mmol/l). Los valores medios de RPE de los deportistas en competición (6 ± 1,5 mmol/l) fueron un 21% inferiores a los obtenidos para la intensidad del VT2 (7,6 ± 0,8 mmol/l). La intensidad y la respuesta al esfuerzo son mayores y se mantienen por encima del VT2 durante la competición en tiradores TOW al final de los tirones (6 ± 1,9 mmol/l) fueron un 32% más altas que los valores.

GROWTH OF THE HEART RELATED TO BODILY GROWTH DURING CHILDHOOD AND ADOLESCENCE

PEDIATRICS ◽  
1948 ◽  
Vol 2 (4) ◽  
pp. 382-404
Author(s):  
MARION M. MARESH
Keyword(s):  
Internal Diameter ◽  
Childhood And Adolescence ◽  
Transverse Diameter ◽  
Healthy Children ◽  
Mean Values ◽  
Wide Range ◽  
The Mean ◽  
The Individual ◽  
Range Of Variation ◽  
Medium Weight

As part of a longitudinal study of healthy children by the staff of the Child Research Council, roentgenograms of the chest have been made at frequent intervals. Three cardiac diameters (transverse, long, and broad) and the internal diameter of the chest were measured on each of 3205 of these roentgenograms, taken of 128 subjects over a period of years. The size and shape of the heart are illustrated and discussed with emphasis on the range of variation that is seen in healthy individuals and on the inadequacy of one set of "normal standards" for evaluating the cardiac silhouette. In spite of fluctuations in the growth curves for the cardiac diameters, a general pattern of agreement was found in the increases in the cardiac diameters and the increases in body height and weight during childhood and adolescence. It would seem that periods of rapid growth such as are usually seen in adolescence are frequently coincident with fairly rapid increases in the cardiac diameters, suggesting that cardiac demands are greater during such growth spurts. The mean values for transverse diameter of the heart showed the same type of sex differentiation that is found in the mean values for height and weight in boys and girls. It seems logical to assume that changing cardiac size should be considered as part of the growth process rather than as an isolated physical and physiologic process. The relations that seem apparent between transverse diameter of the heart and height, weight, and internal diameter of the chest could not be proved statistically by calculated coefficients of correlation. However, it was possible to show differences in the mean values for cardiac transverse diameter in three groups, classified as to height-weight relationships into overweight, medium-weight, and underweight individuals. The mean values were greatest for the fat group, least for the thin group and intermediate for the group that was of medium weight for height. Body build may therefore be a factor in determining cardiac size during childhood as well as during adolescence and adult life. Since the width of the chest is increasing during childhood and adolescence in much the same manner that the transverse diameter of the heart is increasing, cardiothoracic ratios do not become progressively greater with advancing age. In fact, the successive ratios on the same individual show little regularity toward either increase or decrease although mean values for the different ages do decrease from a high of 0.44 at four years of age to a low of 0.40 in the post-adolescent age groups. Each individual showed considerable fluctuation in the cardio-thoracic ratios but no one person fluctuated as much as the range for the whole group. No ratios were found above 0.50 or below 0.32. No sex differences were found nor was there any significant difference in the cardio-thoracic ratios for the groups of different height-weight proportions. In evaluating the heart size of an individual from a single film, the cardio-thoracic ratio is probably as satisfactory as any other measurement if one recognizes the wide range of healthy variation. An increase in the cardio-thoracic ratio on successive roentgenograms might be more significant clinically than cardiac measurements which did not take into consideration the growth of the individual. The nomogram constructed by Ungerleider based on height and weight for prediction of transverse diameter of the heart on teleoroentgenograms of adults was tested for its applicability to the later childhood, adolescent and early adult periods. Nearly half the predicted cardiac transverse diameters exceeded the measured values by 10% or more. This study would seem to indicate, therefore, that one should not be discouraged by the range of variation or the fluctuations in cardiac measurements from routine roentgenograms of the chest. Valuable information regarding the significance of the size of the heart can be obtained from such roentgenograms if one relates those data to the basic process of growth and maturation of the individual.

scholarly journals Selection in sugarcane families with artificial neural networks

2015 ◽  
Vol 15 (2) ◽  
pp. 72-78 ◽  
Author(s):  
Bruno Portela Brasileiro ◽  
Caillet Dornelles Marinho ◽  
Paulo Mafra de Almeida Costa ◽  
Cosme Damião Cruz ◽  
Luiz Alexandre Peternelli ◽  
...  
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Selection Process ◽  
Selection Strategy ◽  
Ann Model ◽  
Best Linear Unbiased Predictor ◽  
Individual Level ◽  
Best Linear Unbiased ◽  
Artificial Neural ◽  
The Individual

The objective of this study was to evaluate Artificial Neural Networks (ANN) applied in an selection process within sugarcane families. The best ANN model produced no mistake, but was able to classify all genotypes correctly, i.e., the network made the same selective choice as the breeder during the simulation individual best linear unbiased predictor (BLUPIS), demonstrating the ability of the ANN to learn from the inputs and outputs provided in the training and validation phases. Since the ANN-based selection facilitates the identification of the best plants and the development of a new selection strategy in the best families, to ensure that the best genotypes of the population are evaluated in the following stages of the breeding program, we recommend to rank families by BLUP, followed by selection of the best families and finally, select the seedlings by ANN, from information at the individual level in the best families.

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