Improvement of Precision by Repeated Measurements. Application to Analytical Control Methods

1946 ◽  
Vol 18 (5) ◽  
pp. 280-284 ◽  
Author(s):  
John Mandel
Keyword(s):  
Repeated Measurements ◽  
Analytical Control ◽  
Control Methods

Precision and Accuracy of Colorimetric Procedures as Analytical Control Methods Determination of Silica

1944 ◽  
Vol 16 (7) ◽  
pp. 462-464 ◽  
Author(s):  
Allen L. Olsen ◽  
Edwin A. Gee ◽  
Verda. McLendon ◽  
Delwin D. Blue
Keyword(s):  
Analytical Control ◽  
Control Methods ◽  
Precision And Accuracy

PROBLEMS OF ANALYTICAL CONTROL IN PRODUCTION OF RARE AND PRECIOUS METALS

2018 ◽  
pp. 19-35
Author(s):  
Yu. A. Karpov ◽  
V. B. Baranovskaya
Keyword(s):  
Metrological Support ◽  
Analytical Methods ◽  
Precious Metal ◽  
Precious Metals ◽  
Analytical Control ◽  
Control Methods ◽  
Metal Production ◽  
Research Activities ◽  
International Comparative ◽  
Analytical Laboratories

The article focuses on one of the important issues in rare and precious metals industry development – analytical control. It reviews the current state, importance, problems and prospects for analytical control development as an integral part of the rare and precious metal production and product quality assurance. Modern analytical control methods are described, namely atomic spectral, mass spectral, X-ray fluorescent and combined ones as well as their rational applications. It is shown that scientific and technological progress is inextricably linked with a drastic increase in the nomenclature of materials based on rare and precious metals and higher requirements for their quality. This will require creating new and improving existing analytical control methods, their standardization and metrological support. This work should involve research organizations in theRussianAcademy of Sciences, universities, industry research centers with research laboratories that have survived in the country after theSoviet Union dissolution, as well as promote plant research activities. It is necessary to effectively use the achievements of advanced analytical laboratories abroad, participate in international comparative tests. At the same time, special attention is paid to unsolved problems – scientifically justified statement of requirements for new types of products based on rare and precious metals; development and metrological assessment of sampling methods; development of high-quality metrological support for analytical control of rare and precious metal production; improvement of analytical methods; standardization of analytical methods; accreditation of analytical laboratories; training of highly qualified analytical chemists.

Modeling Intraindividual Variability in Three-Level Multilevel Models

Methodology ◽  
2018 ◽  
Vol 14 (3) ◽  
pp. 95-108 ◽  
Author(s):  
Steffen Nestler ◽  
Katharina Geukes ◽  
Mitja D. Back
Keyword(s):  
Multilevel Model ◽  
Multilevel Models ◽  
Mixed Effects ◽  
Repeated Measurements ◽  
Scale Model ◽  
Suggested Approach ◽  
Psychological Study ◽  
Level Data ◽  
Ecological Momentary ◽  
Momentary Assessment

Abstract. The mixed-effects location scale model is an extension of a multilevel model for longitudinal data. It allows covariates to affect both the within-subject variance and the between-subject variance (i.e., the intercept variance) beyond their influence on the means. Typically, the model is applied to two-level data (e.g., the repeated measurements of persons), although researchers are often faced with three-level data (e.g., the repeated measurements of persons within specific situations). Here, we describe an extension of the two-level mixed-effects location scale model to such three-level data. Furthermore, we show how the suggested model can be estimated with Bayesian software, and we present the results of a small simulation study that was conducted to investigate the statistical properties of the suggested approach. Finally, we illustrate the approach by presenting an example from a psychological study that employed ecological momentary assessment.

Summary and Conclusions of a Review of Prescription Drug Diversion Control Methods

1993 ◽  
Author(s):  
Constance Horgan ◽  
◽  
Jeffrey Prottas ◽  
Christopher Tompkins ◽  
Linda Wastila ◽  
...  
Keyword(s):  
Prescription Drug ◽  
Control Methods ◽  
Drug Diversion

Use of a Lyophilized Reference Plasma to Compare Coagulation Test Procedures

1975 ◽  
Vol 34 (02) ◽  
pp. 426-444 ◽  
Author(s):  
J Kahan ◽  
I Nohén
Keyword(s):  
Oral Anticoagulant Therapy ◽  
Repeated Measurements ◽  
Test Procedures ◽  
Coagulation Activity ◽  
Close Relationship ◽  
Measured Activity ◽  
Test Materials ◽  
The Difference ◽  
The Stability ◽  
The One

SummaryIn 4 collaborative trials, involving a varying number of hospital laboratories in the Stockholm area, the coagulation activity of different test materials was estimated with the one-stage prothrombin tests routinely used in the laboratories, viz. Normotest, Simplastin-A and Thrombotest. The test materials included different batches of a lyophilized reference plasma, deep-frozen specimens of diluted and undiluted normal plasmas, and fresh and deep-frozen specimens from patients on long-term oral anticoagulant therapy.Although a close relationship was found between different methods, Simplastin-A gave consistently lower values than Normotest, the difference being proportional to the estimated activity. The discrepancy was of about the same magnitude on all the test materials, and was probably due to a divergence between the manufacturers’ procedures used to set “normal percentage activity”, as well as to a varying ratio of measured activity to plasma concentration. The extent of discrepancy may vary with the batch-to-batch variation of thromboplastin reagents.The close agreement between results obtained on different test materials suggests that the investigated reference plasma could be used to calibrate the examined thromboplastin reagents, and to compare the degree of hypocoagulability estimated by the examined PIVKA-insensitive thromboplastin reagents.The assigned coagulation activity of different batches of the reference plasma agreed closely with experimentally obtained values. The stability of supplied batches was satisfactory as judged from the reproducibility of repeated measurements. The variability of test procedures was approximately the same on different test materials.

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