Comparison of two surface-wave magnitude scales: M of Gutenberg and Richter (1954) and MS of “Preliminary determination of epicenters”

1984 ◽  
Vol 74 (6) ◽  
pp. 2357-2378
Author(s):  
J. J. Lienkaemper
Keyword(s):  
Standard Deviation ◽  
Surface Wave ◽  
Ad Hoc ◽  
Surface Wave Magnitude ◽  
Single Station ◽  
Magnitude Scales ◽  
The Mean ◽  
Probabilistic Criteria ◽  
Preliminary Determination

Abstract The Prague formula (Vanek et al., 1962), which is used for Preliminary Determination of Epicenters (PDE) magnitudes, exceeds that of Gutenberg (1945) by 0.19 unit of MS, leading to the false assumption that mean MS of PDE are inherently 0.19 larger than Gutenberg and Richter (1954) magnitudes, MGR. Recomputation of MS using Gutenberg's methods and Gutenberg-Richter (G-R) notepad data shows that MS values in the G-R notepads are ∼0.1 unit of MS too large on average, while MGR values are 0.05 larger still. Total inflation of MGR over recomputed MS values is 0.16 on average. MS for the same events recomputed with the Prague formula are thus only 0.03 unit of MS higher on average than MGR. Thus, PDE values of MS are on average directly comparable to MGR. This relationship probably is a consequence of the Prague formula having been calibrated to Gutenberg's revised magnitudes and MGR values. Surface-wave magnitude residuals summed over many events appear to fit a normal Gaussian distribution with a standard deviation of 0.28 unit-of-MS for two large independent samples. Thus, anomalous single-station MS values can be excluded from averaging, using probabilistic criteria rather than the ad hoc criteria used currently, and standard deviations of MS from the mean are valid estimates of error.

Determination of Maleic Hydrazide Residues in Tobacco and Vegetables

1973 ◽  
Vol 56 (5) ◽  
pp. 1164-1172
Author(s):  
Milan Ihnat ◽  
Robert J Westerby ◽  
Israel Hoffman
Keyword(s):  
Standard Deviation ◽  
Present Method ◽  
Maleic Hydrazide ◽  
Collaborative Study ◽  
Official Method ◽  
Sample Weight ◽  
Relative Standard ◽  
The Mean ◽  
Pipe Tobacco

Abstract The distillation-spectrophotometric method of Hoffman for determining maleic hydrazide has been modified to include a double distillation and was applied to the determination of 1–30 ppm maleic hydrazide residues in tobacco and vegetables. Recoveries of 1–23 μg added maleic hydrazide were independent of weight of maleic hydrazide, but did depend on sample and sample weight. The following recoveries were obtained from 0.5 g sample: pipe tobacco, 84%; commercially dehydrated potato, 83%; cigar tobacco, 81%; dried potato, 76%; fluecured tobacco, 73%; dried carrot, 71%. In the absence of sample, the recovery was 82%. When appropriate standard curves were used, maleic hydrazide levels determined in tobacco samples were essentially independent of sample weight in the range 0.1–3 g. The mean relative standard deviation for a variety of field-treated and fortified tobacco samples containing 1–28 ppm maleic hydrazide was 3%. The precision and sensitivity of this procedure seem to be substantial improvements over official method 29.111–29.117. It is recommended that the present method be subjected to a collaborative study.

Fluorometric Determination of Selenium in Foods

1974 ◽  
Vol 57 (2) ◽  
pp. 368-372 ◽  
Author(s):  
Milan Ihnat
Keyword(s):  
Standard Deviation ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Food Samples ◽  
Fluorometric Method ◽  
Fluorometric Determination ◽  
Relative Standard ◽  
The Mean

Abstract A fluorometric method using 2,3-diaminonaphthalene for estimating selenium has been evaluated with regard to its applicability to food samples. Charring of the sample during digestion appeared to result in losses of native and added selenium from some samples, so a modified wet digestion procedure was introduced. Digestion first in nitric acid followed by a mixture of nitric-perchloric-sulfuric acids substantially reduced the incidence of sample charring for a variety of foods. The mean apparent recovery of selenium added as selenite or selenate at 100 and 500 ng levels to 0.1 and 1.0 g corn cereal, skim milk powder, and meat and 0.1 g fish was 101.0%; the actual recovery of the same levels of selenium from standard solutions was 96.6%. For a variety of samples containing 5—750 ng native or added selenium, the standard deviation as 4.7 + 1.95 X 10-2W ng, where W = ng selenium in the sample taken for analysis. The relative standard deviation (RSD) as a function of selenium weight (ng) was 50% (10), 6.7% (100), 4.3% (200), 3.1% (400), 2.7% (600), and 2.5% (800). The detection limit (weight of selenium at which RSD = 50%) was 10 ng at a mean blank level of 25 ng.

Radioisotope Dilution Technique for Determination of Vitamin B12 in Foods

1982 ◽  
Vol 65 (1) ◽  
pp. 85-88 ◽  
Author(s):  
Patrick J Casey ◽  
Keevin R Speckman ◽  
Frank J Ebert ◽  
William E Hobbs
Keyword(s):  
Standard Deviation ◽  
Vitamin B12 ◽  
Relative Standard Deviation ◽  
Extraction Procedure ◽  
Dilution Technique ◽  
Microbiological Method ◽  
Relative Standard ◽  
Wide Range ◽  
The Mean

Abstract A radioisotope dilution (RID) method for the determination of vitamin B12 is presented. The method combines a standard extraction procedure (AOAC 43.108,12th ed.) with a commercially available RID assay kit. The method was evaluated on a wide range of fortified and unfortified food products. Recovery studies on both groups yielded average recoveries of 98.1 and 95.8%, respectively. Reproducibility data generated from replicate analyses on both groups gave a relative standard deviation of 6.9% for the fortified group and 9.2% for the unfortified group. For the samples studied, the mean vitamin B12 content determined by the RID method was 8.01 μg/100 g vs imean of 7.54 μg/100 g by the AOAC microbiological method; the correlation coefficient was r = 0.983.

A simple spectroturbidimetric method for the determination of the fat content of homogenized ice-cream mixes

1962 ◽  
Vol 29 (1) ◽  
pp. 47-53 ◽  
Author(s):  
J. D. S. Goulden ◽  
P. Sherman
Keyword(s):  
Standard Deviation ◽  
Ice Cream ◽  
Fat Content ◽  
Fat Globule ◽  
The Mean ◽  
Simple Filter

SummaryA rapid spectroturbidimetric method for the determination of the fat content of homogenized ice-cream mixes using a simple filter absorptiometer has been devised. Turbidities are measured at two different wavelengths to allow for changes in the degree of homogenization. The standard deviation of the differences from the values obtained by the Werner-Schmid method was found to be 2·5% of the mean fat content value. The method also enables the mean fat globule diameter to be determined.

Ion Exchange Separations and Atomic Absorption Determination of Trace Metals in Ores after Basic Fusion

1972 ◽  
Vol 26 (2) ◽  
pp. 302-305 ◽  
Author(s):  
T. W. Freudiger ◽  
C. T. Kenner
Keyword(s):  
Standard Deviation ◽  
Ion Exchange ◽  
Metal Ions ◽  
Atomic Absorption ◽  
Strong Acid ◽  
Ion Exchange Resin ◽  
High Concentration ◽  
The Mean ◽  
Trace Constituents

The determination of trace constituents in ores by atomic absorption after basic fusion and solution in strong acid is erratic due to the light scattering and aspirator clogging of the high concentration of sodium salts. The sodium is separated from the trace constituents using a column procedure and an iminodiacetate chelating ion exchange resin which will retain di- and trivalent metal ions at pH values above 6.0 but will not retain alkali metal ions. The trace constituents are determined by atomic absorption after elution with HCl. The precision (standard deviation of the mean) of the atomic absorption method is increased at least fivefold by the resin separation and the method is applicable to concentrations in the low ppm range. The standard deviation of the mean for an NBS sample containing 0.007% Cu is 0.0004%.

scholarly journals Station correction analysis for surface-wave magnitudes of New Zealand earthquakes

1999 ◽  
Vol 32 (1) ◽  
pp. 21-29 ◽  
Author(s):  
D. A. Rhoades ◽  
D. J. Dowrick
Keyword(s):  
New Zealand ◽  
Surface Wave ◽  
Linear Model ◽  
World Wide ◽  
Vertical Component ◽  
Horizontal Component ◽  
Standard Errors ◽  
Station Correction ◽  
The Mean

Station terms and standard errors are presented for 345 world-wide stations used in the determination of surface-wave magnitudes of 190 selected New Zealand earthquakes over the period 1901-1993 [1]. These will facilitate the estimation of surface-wave magnitudes of other earthquakes in the New Zealand region. The station terms and the residuals from the linear model used to estimate them are both found to be weakly related to the mean distance from the earthquakes recorded by each station. The horizontal and vertical components at a given site are treated as separate stations. The station term for the horizontal component tends to exceed that for the vertical component at mean distances in the 20°-40° range.

A New and Rapid Determination of Pyridinium Aldoximes in Blood and Urine

1969 ◽  
Vol 15 (1) ◽  
pp. 72-83 ◽  
Author(s):  
William A Groff ◽  
Robert I Ellin
Keyword(s):  
Standard Deviation ◽  
Transfer Rate ◽  
Rapid Determination ◽  
Accurate Method ◽  
Small Sample ◽  
Basic Solution ◽  
Pyridinium Oximes ◽  
Average Variation ◽  
The Mean

Abstract A rapid and accurate method for analyzing pyridinium oximes—N-methylpyridinium-2-aldoxime chloride, N,N'-trimethylene-(pyridinium-4-aldoxime) dihalide, and N,N'-oxydimethyl-(pyridinium-4-aldoxime) dichloride—in plasma, urine, and whole blood is described. The method is completely automated and requires small sample volumes. Concentrations ranging from 3 to 120 µEq./L. in biologic fluids can be determined at a rate of 40 samples per hour. This technic can be applied to oximes which are unstable in basic solution. The average variation of the oxime concentration used to establish calibration curves, as determined by the ratio of the standard deviation to the mean, was ± 1.5%. Plasma and albumin increase the transfer rate of the oximes through the dialyzing membrane. Theoretical concentrations to explain this phenomenon are presented.

scholarly journals Determination of Inulin in Foods

2000 ◽  
Vol 83 (3) ◽  
pp. 675-678 ◽  
Author(s):  
Breda Simonovska
Keyword(s):  
Standard Deviation ◽  
Oxalic Acid ◽  
Thin Layer ◽  
Degree Of Polymerization ◽  
Test Solution ◽  
Boiling Water Bath ◽  
Before And After ◽  
The Mean ◽  
The Difference

Abstract A method was developed for determining fructan inulin in various foods (yogurts, honey cakes, chocolates). Warm water was applied for extraction of samples, and mono- and dissacharides were determined by a thin-layer chromatographic densitometric method. A portion of the test solution was hydrolyzed 30 min with 1% oxalic acid in a boiling water bath. Fructose was determined in the hydrolysate. The amount of inulin in a sample was calculated as the difference between the amount of fructose in the sample before and after hydrolysis. The fructose from sucrose formed during the hydrolysis was also considered. The mean recovery from yogurt fortified with 4% inulin was 95.5 ± 4.5% (mean ± standard deviation); from honey cakes extract fortified with 10% inulin, 97.3 ± 5.5%; and from chocolate extract fortified with 30% inulin, 98.6 ± 6.6% (6 replicates in all cases). Determination of glucose is not necessary for analyzing fructans with the composition expressed shortened to GFn−1 (G, glucose; F, fructosyl) with the average degree of polymerization 8 ≤ n ≤ 15.

The study of variability in some wool traits in a coarse wool breed of sheep

1973 ◽  
Vol 80 (2) ◽  
pp. 233-238 ◽  
Author(s):  
R. A. Guirgis
Keyword(s):  
Statistical Analysis ◽  
Standard Deviation ◽  
Major Part ◽  
Fibre Diameter ◽  
Coefficient Of Determination ◽  
Main Contributor ◽  
Total Variability ◽  
The Mean ◽  
Staple Length

SummaryWool samples from 47 Barki yearlings were taken from five positions during two years to study the variability in the fleece, the cause of variability and associations between different fleece traits. Statistical analysis has indicated the following significant points.An antero-posterior gradient occurred in the different traits under study. When medullation was discarded, though it was of a low magnitude (3·9%), a reduction of 5·89% in the mean fibre diameter and of 18·33% in its standard deviation occurred.The position most representative of the whole fleece varied with the trait. It is recommended to take three sampling positions forming a triangle, withers, mid-side and hip, to represent the Barki fleece.The animals contributed the major part in the variability of mean fibre diameter (1), the standard deviation of fibre diameter (S.D.1), percentage medullation, mean fibre diameter after discarding the medullated fibres (2), the standard deviation of fibre diameter after discarding the medullated fibres (S.D.2), the contribution of medullation to the total variability, percentage fine fibres and percentage coarse fibres. The positions were the main contributor to the variability of percentage kemp fibres, staple length, medullation index and to a certain extent to that of the kemp score. The year played a significant part in the variability except for 2 and S.D.2.The highest correlations with the standard deviation of fibre diameter were those of percentage medullation and kemp score. These three variables when considered separately accounted for 0·47, 0·35 and 0·31 respectively of the variability in S.D.Equations were obtained to predict the standard deviation from both the mean fibre diameter and the percentage medullation and to predict the mean fibre diameter from the staple length and the kemp score. The coefficient of determination of the first set of equations ranged from 0·47 to 0·56 while that of the second set ranged between 0·07 and 0·51 for different positions.

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