Fitting straight lines to experimental data

1977 ◽  
Vol 233 (3) ◽  
pp. R94-R99 ◽  
Author(s):  
R. A. Brace
Keyword(s):  
Standard Error ◽  
Least Squares Regression ◽  
Simple Method ◽  
Mean Values ◽  
Absolute Value ◽  
Best Value ◽  
The Mean ◽  
Straight Lines ◽  
Relationship Of ◽  
Conventional Regression

The problem associated with use of statistical methods for determining a best linear relationship of the form Y = AX +B have been examined for a condition quite prevalent with experimental research, i.e., when the values of both variables are subject to essentially unknown errors. Under this condition standard least-squares regression analysis underestimates the value of the slope A. A very simple method for determining the best value of the slope and intercept has been introduced which can be used when errors are present in both variables. With this proposed method, the calculated slope is equal to the standard error of Y divided by the standard error of X (with the appropriate sign) and the intercept is found from the mean values of X and Y, i.e., B = Y - AX. The best estimate of the slope is also equal to the slope found with the conventional regression method divided by the absolute value of the correlation coefficient. The line determined with the suggested method can be considered to be a line of symmetry through the data.

A COMPARISON OF TWO METHODS FOR MEASUREMENT OF ALDOSTERONE SECRETION RATE IN MAN

1966 ◽  
Vol 53 (2) ◽  
pp. 177-188 ◽  
Author(s):  
P. Lund-Johansen ◽  
T. Thorsen ◽  
K. F. Støa
Keyword(s):  
Urinary Excretion ◽  
Normal Subjects ◽  
Secretion Rate ◽  
Aldosterone Secretion ◽  
Simple Method ◽  
Mean Values ◽  
Pathological Conditions ◽  
Significant Difference ◽  
Derivative Method ◽  
The Mean

ABSTRACT A comparison has been made between (A), a relatively simple method for the measurement of aldosterone secretion rate, based on paper chromatography and direct densitometry of the aldosterone spot and (B) a more elaborate isotope derivative method. The mean secretion rate in 9 normal subjects was 112 ± 26 μg per 24 hours (method A) and 135 ± 35 μg per 24 hours (method B). The »secretion rate« in one adrenalectomized subject after the intravenous injection of 250 μg of aldosterone was 230 μg per 24 hours (method A) and 294 μg per 24 hours (method B). There was no significant difference in the mean values, and correlation between the two methods was good (r = 0.80). It is concluded that the densitometric method is suitable for clinical purposes as well as research, being more rapid and less expensive than the isotope derivative method. Method A also measures the urinary excretion of the aldosterone 3-oxo-conjugate, which is of interest in many pathological conditions. The densitometric method is obviously the less sensitive and a prerequisite for its use is an aldosterone secretion of 20—30 μg per 24 hours. Lower values are, however, rare in adults.

EVALUATION OF FLAME PHOTOMETRIC DETERMINATION OF MAGNESIUM IN PLANT MATERIAL

1964 ◽  
Vol 44 (6) ◽  
pp. 520-524
Author(s):  
A. A. MacLean
Keyword(s):  
Standard Error ◽  
Plant Material ◽  
Photometric Determination ◽  
Flame Photometry ◽  
Mean Values ◽  
Edta Titration ◽  
The Mean ◽  
Flame Method ◽  
Oxyhydrogen Flame

Flame methods for the determination of magnesium in plant material were compared with EDTA titration and a thiazole yellow procedure. Mean values for quadruplicate determinations on 24 samples were 0.544, 0.543, 0.532, and 0.514% for EDTA, flame photometry with an oxyhydrogen flame, thiazole yellow, and flame photometry with an oxyacetylene flame respectively.The degree of precision, as indicated by the standard error of the mean, was highest for the oxyhydrogen flame method and lowest when the oxyacetylene flame was used.Silica repressed magnesium emission with either flame source but degree of interference was greater with the oxyhydrogen flame.

scholarly journals Measurements of CFC-11, CFC-12, and HCFC-22 total columns in the atmosphere at the St. Petersburg site in 2009–2019

2020 ◽  
Author(s):  
Alexander Polyakov ◽  
Anatoly Poberovsky ◽  
Maria Makarova ◽  
Yana Virolainen ◽  
Yuri Timofeyev
Keyword(s):  
Seasonal Variability ◽  
Climate Model ◽  
Independent Data ◽  
Mean Values ◽  
Absolute Value ◽  
Qualitative And Quantitative ◽  
Observational Site ◽  
Retrieval Strategies ◽  
The Mean ◽  
The Absolute

Abstract. The retrieval strategies for deriving the atmospheric total columns (TCs) of CFC-11 (CCl3F), CFC-12 (CCl2F2), and HCFC-22 (CHClF2) from ground–based measurements of IR solar radiation have been improved. We demonstrate the advantage of using the Tikhonov-Phillips regularization approach for solving the inverse problem of the retrieval of these gases and give the optimized values of regularization parameters. The estimates of relative systematic and random errors amount to 7.61 % and 3.08 %, 2.24 % and 2.40 %, 5.75 % and 3.70 %, for CFC-11, CFC-12, and HCFC-22, respectively. We analyze the time series of the TCs and mean molar fractions (MMFs) of CFC-11, CFC-12, and HCFC-22 measured at the NDACC site St. Petersburg located near Saint Petersburg, Russia for the period of 2009–2019. Mean values of the MMFs for CFC-11, CFC-12, and HCFC-22 total 225, 493, and 238 pptv, respectively. Estimates of the MMFs trends for CFC-11, CFC-12, and HCFC-22 account for −0.40 ± 0.07 %/yr, -0.49  ±0.05 %/yr, and 2.12±0.13 %/yr, respectively. We have compared the mean values, trends and seasonal variability of CFC-11, CFC-12, and HCFC-22 MMFs measured at the St. Petersburg site in 2009–2019 to that of 1) near–ground volume mixing ratios (VMRs) measured at the observational site Mace Head, Ireland (GVMR); 2) the mean in the 8–12 km layer VMRs measured by ACE–FTS and averaged over 55–65° N latitudes (SVMR); and the MMFs of the Whole Atmosphere Community Climate Model for the St. Petersburg site (WMMF). The means of the MMFs are less than that of the GVMR for CFC-11 by 9 pptv (3.8 %), for CFC-12 by 24 pptv (4.6 %); for HCFC-22, the mean MMFs does not differ significantly from the mean GVMR. The absolute value of the trend estimates of the MMFs is less than that of the GVMR for CFC-11 (−0.40 vs −0.53 %/yr) and CFC-12 (−0.49 vs −0.59 %yr); the trend estimate of the HCFC-22 MMFs does not differ significantly from that of the GVMR. The seasonal variability of the GVMR for all three gases is much lower than the MMFs variability. The means of the MMFs are less than that of the SVMR for CFC-11 by 10 pptv (4.3 %), for CFC-12 by 33 pptv (6.3 %), and for HCFC-22 by 2 pptv (0.8 %). The absolute value of the trend estimates of the MMFs is less than that of the SVMR for CFC-11 (−0.40 vs −0.63 %/yr) and CFC-12 (−0.49 vs −0.58 %/yr); the trend estimate of the HCFC-22 MMFs does not differ significantly from that of the SVMR. The MMF and SVMR values show nearly the same qualitative and quantitative seasonal variability for all three gases. The means of the MMFs are greater than that of the WMMF for CFC-11 by 22 pptv (10 %), for CFC-12 by 15 pptv (3.1 %), and for HCFC-22 by 23 pptv (10 %). The absolute value of the trend estimates of the MMFs is less than that of the WMMF for CFC-11 (−0.40 vs −1.68 %/yr), CFC-12 (−0.49 vs −0.84 %/yr), and HCFC-22 (2.12 %/yr vs 3.40 %/yr). The MMFs and WMMF values show nearly the same qualitative and quantitative seasonal variability for CFC-11 and CFC-12, whereas the seasonal variability of the WMMF for HCFC-22 is essentially less than that of the MMFs. In general, the comparison of the MMFs with the independent data shows a good agreement of their means within the systematic error of considered measurements. The observed trends over the St. Petersburg site demonstrate the smaller decrease rates for CFC-11 and CFC-12 TCs than that of the independent data, and the same decrease rate for HCFC-22. The suggested retrieval strategies can be used for analysis of the IR solar spectra measurements using Bruker FS125HR spectrometers, e.g. at other IRWG sites of the NDACC observational network.

Asymptotic Analysis of Wave Resistance of a Submerged Body Moving with an Oscillating Velocity

1993 ◽  
Vol 37 (02) ◽  
pp. 119-125
Author(s):  
N. G. Kuznetsov
Keyword(s):  
Perturbation Technique ◽  
Mean Value ◽  
Wave Resistance ◽  
The Body ◽  
Singular Perturbation Technique ◽  
Mean Values ◽  
Absolute Value ◽  
Submerged Body ◽  
Short Period ◽  
The Mean

An asymptotic study is made of potential and tree-surface elevation due to forward motion of a submerged body with an oscillating velocity. The latter is supposed to be a short period. As the nondimensional period ε 1, the singular perturbation technique is applied. Using two-term expansion for the potential, the principal terms of asymptotics for instant and mean values of wave resistance are obtained. The mean value (up to a term 0(e)) is the sum of two addends, the first of which is the wave resistance of the same body moving at the mean speed. The second addend is proportional to the dispersion of velocity with the coefficient depending on the form of the body. This coefficient vanishes if the body is symmetric with respect to the mid-section. Numerical examples for the two-dimensional problem show that there exist cylinders with the following property: the absolute value of wave resistance decreases when passing from motion at the mean speed to motion with oscillating velocity.

scholarly journals Association of the Q141K polymorphism of the ABCG2 gene with the effectiveness of urate-lowering therapy in patients with gout (a pilot study)

2021 ◽  
Vol 15 (6) ◽  
pp. 55-60
Author(s):  
M. S. Eliseev ◽  
M. N. Chikina ◽  
I. A. Guseva ◽  
O. V. Zhelyabina ◽  
E. Yu. Samarkina ◽  
...  
Keyword(s):  
Uric Acid ◽  
Glomerular Filtration Rate ◽  
Pilot Study ◽  
Filtration Rate ◽  
Mean Values ◽  
Lowering Therapy ◽  
The Mean ◽  
Relationship Of ◽  
The Relationship ◽  
Abcg2 Gene

Achieving the target serum uric acid (UA) level is a priority in the treatment of gout.Objective: to study the relationship of the ABCG2 gene polymorphism (rs2231142) with the efficacy of allopurinol and febuxostat in patients with gout.Patients and methods. The study included 82 patients with gout over 18 years of age with serum UA level >360 μmol/L who did not take uratelowering therapy.All patients were prescribed allopurinol 100 mg daily, followed by its titration until the target UA level was reached (<360 μmol/L or <300 μmol/L in patients with chronic tofus gout), up to a maximum of 900 mg/day, in patients with glomerular filtration rate <60 ml/min/1.73 m2 – up to 300 mg/day. Patients who did not reach the target UA level when using allopurinol were prescribed febuxostat 80 mg/day, which, if necessary, was increased to 120 mg/day. Monitoring of each patient was continued until the target serum UA level was reached.All patients underwent genotyping of the C>A polymorphism (rs2231142) of the ABCG2 gene. We compared the probability of achieving the target UA level, the mean values of a decrease in the serum UA level, and the mean doses of urate-lowering drugs in patients with different genotypes (CC, CA, AA) of the ABCG2 gene.Results and discussion. The target UA level in 45 (55%) of 82 patients was defined as <300 μmol/L, in the remaining 37 – as <360 μmol/L.In 26 patients, the dose of allopurinol did not exceed 300 mg/day. In 28 (34%) patients treated with allopurinol, the target UA level was achieved, in the remaining 54 (66%) patients, allopurinol was substituted by febuxostat, and in 22 (41%) of them the UA level decreased and was below the target.The CC genotype of the ABCG2 gene was detected in 51 (62%) patients, the CA genotype in 30 (37%) and the minor genotype AA in 1 (1%).The probability of achieving the target UA level during therapy with allopurinol in carriers of homozygous CC genotype and genotypes CA or AA did not differ: 17 (33%) and 11 (35%) cases, respectively, but patients with CA and AA genotypes required a significantly higher dose of allopurinol (365±102 mg/day) than patients with the CC genotype (290±85 mg/day), p=0.002. Of the 54 patients who took febuxostat and did not reach the target UA level, 30 (56%) had the CC genotype and 24 (44%) had the CA genotype, the probability of reaching the target UA level was also comparable (p=0.22).Conclusion. The probability of reaching the target serum UA level in patients with gout taking allopurinol is not associated with the C>A polymorphism of the ABCG2 gene, but the presence of CA and AA genotypes is identified with a higher dose of the drug. The C>A (rs2231142) polymorphism of the ABCG2 gene does not affect the ability to achieve the goal of therapy when using febuxostat in patients with allopurinol ineffectiveness.

scholarly journals The relationship of religious attitude with self-control andself-discrepancy in students

2019 ◽  
Vol 21 (3) ◽  
pp. 144-148
Author(s):  
Masoud Nikfarjam ◽  
Elham-Sadat Salehi ◽  
Ali Ahmadi
Keyword(s):  
Pearson Correlation ◽  
Self Control ◽  
Cross Sectional ◽  
Mean Values ◽  
Religious Attitude ◽  
Significant Difference ◽  
The Mean ◽  
Self Discrepancy ◽  
Relationship Of ◽  
The Relationship

Background and Aim: Spiritual attitude is one of the factors affecting mental health of students. The purpose of this study was to determine the relationship of religious attitudes with self-control and self-discrepancy (S-D) in students of Shahrekord University of Medical Sciences (SKUMS) in 2017. Methods: In this cross-sectional study, 328 students of the SKUMS were studied. The participants completed Tangney Self-control Survey, Higgins Self-discrepancy Questionnaire, a religious attitude questionnaire, and a checklist of demographic information. For data analysis, in addition to descriptive statistics, independent t-test, Pearson correlation coefficient, and one-way ANOVA were used. Stata software was used to analyze the data. Results: The mean values of religious attitude, self-control, and self-discrepancy were higher in women in comparison with men (P< 0.05). There was a significant difference between self-control religious beliefs, actual-self minus actual-self (S-D2), and self-discrepancy in terms of total monthly income of all family members (P< 0.05). Academic discipline was significantly associated with religious attitude, ideal-self minus actual-self (S-D1), S-D2, and S-D (P< 0.05), but self-control difference was not significant (P= 0.84). There was a linear relationship, significant correlation of religious attitude with the mean values of self-control, required self, actual-self, idea-self, self-discrepancy, and S-D1 and S-D2 (P< 0.05). Conclusion: According to the results of this study, religious attitude was associated with self-control, self-discrepancy, and their dimensions.

scholarly journals MORPHOMETRIC ANALYSIS OF Coptotermes sp. POPULATION FROM TWO DIFFERENT NESTS

PERENNIAL ◽  
2010 ◽  
Vol 6 (2) ◽  
pp. 60
Author(s):  
Astuti Arif ◽  
Ira Taskirawati ◽  
. Affandi
Keyword(s):  
Standard Deviation ◽  
Morphometric Analysis ◽  
Standard Error ◽  
Subterranean Termite ◽  
Tarsus Length ◽  
Mean Values ◽  
Product Engineering ◽  
Coefficient Of Variability ◽  
The Mean ◽  
Tibia Length

The aim of this research is to study morphmetric variation of external anatomy of subterranean termite (Coptotermes sp.). The samples were collected from two different nests, i.e. Laboratory of Forest Product Engineering and Diversification, Hasanuddin University (site A) and Kompleks Perumahan Dosen Unhas, Tamalanrea (site B). Resulted data were statistically analyzed for mean, standard deviation, standard error and coefficient of variability. The mean values of the different population samples were compared by using student‘t’ test according to SPSS Ver.12. For each individual soldier and worker, 54 variables of external characters were measured. The result showed that some external characters of soldier and worker casts were significantly different with different locations. In soldier casts, eleven of 54 variables were found to be significant different in length and width of caput, length and width metathorax, mesothorax length, length and width of abdomens, scape length, flagellum width, femur width, and width tibia. Whilst, in worker casts, 11 of 54 variables were found to be significant different in mesothorax length, scape length, flagellum width, trochanter width, tibia length, tarsus length, and claw width. However, morph metric of external characters of Coptotermes sp. at two locations was generally relative same in terms of coefficient of variability. Key words: Morphometric analysis, Coptotermes sp.

25% "Error Rate" in Ear Temperature Sensing Device

PEDIATRICS ◽  
1991 ◽  
Vol 87 (3) ◽  
pp. 415-416
Author(s):  
RICHARD D. KENNEY ◽  
JAMES D. FORTENBERRY ◽  
S. SUZETTE SURRATT ◽  
BETH M. RIBBECK
Keyword(s):  
Confidence Intervals ◽  
Error Rate ◽  
Standard Error ◽  
Temperature Sensing ◽  
Reporting Standard ◽  
Data Presentation ◽  
Absolute Value ◽  
Frequency Table ◽  
Mercury Thermometer ◽  
The Mean

In Reply.— We thank Freed and Fraley for their helpful comments as based on a different manner of data presentation. We agree that reporting standard deviations would have been more informative than reporting confidence intervals (standard error of the mean). However, the following frequency table of absolute value of the differences between the two devices demonstrates that 75% of tympanic membrane thermometer readings were within 0.5°C of [See table in the PDF file] glass-mercury thermometer readings and more than 95% are within 1°C.

Relationship of radius to pressure along the aorta in living dogs

1963 ◽  
Vol 18 (6) ◽  
pp. 1111-1117 ◽  
Author(s):  
Dali J. Patel ◽  
Flavio M. De Freitas ◽  
Joseph C. Greenfield ◽  
Donald L. Fry
Keyword(s):  
Cardiac Cycle ◽  
Branching Ratios ◽  
Ascending Aorta ◽  
Post Mortem ◽  
Arterial Tree ◽  
Mean Values ◽  
Living State ◽  
Instantaneous Pressure ◽  
The Mean ◽  
Relationship Of

The instantaneous pressure-radius relationship and mean dimensions were studied at various sites along the aorta in 30 dogs. The pressure-radius relationship was studied in the living state using an electrical caliper to measure the radius continuously through the cardiac cycle. The relative dimensions of the aortic tree at branching sites were calculated from Jeltrate casts made immediately post mortem. The results indicate: 1) The value of ΔR/ΔP and the mean radius decreased with distance along the aorta. 2) The calculated value for Ep, the “pressure-strain elastic modulus” increased monotonically from the ascending aorta to the bifurcation. 3) An “average” arterial tree was constructed from the mean values of the radius obtained from the caliper data and the branching ratios obtained from the casts. elastic properties, aorta; dimensions, dog aorta Submitted on March 5, 1963

scholarly journals Relationships Between Hybrid Performance and Genetic Distance Revealed by Morphological and AFLP Marker in Cucumber

2014 ◽  
Vol 65 (1) ◽  
pp. 87-97
Author(s):  
J.A. Olfati ◽  
H. Samizadeh ◽  
Gh. Peyvast ◽  
B. Rabiei ◽  
S.A. Khodaparast
Keyword(s):  
Genetic Distance ◽  
Aflp Marker ◽  
Molecular Genetic ◽  
Yield Component ◽  
Fruit Color ◽  
Hybrid Performance ◽  
Mean Values ◽  
The Mean ◽  
Relationship Of ◽  
The Relationship

AbstractThis study investigated the relationship of morphological and molecular genetic distance with hybrid performance and heterosis in cucumber in an attempt to make use of genetic distance in predicting hybrid performance. The results of this study showed that GD, in general, correlated poorly with heterosis and SCA. Results showed that the mean values of the hybrids were significantly larger or smaller for many traits when compared with the mean of parental lines, indicating that heterosis was present for these traits. In next step we compare inter group hybrids versus intra group hybrids. This test showed that intra group hybridization although increased the yield and yield component but decrease some fruit quality such as fruit color and shape.

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