Inert gas a-A differences: a direct reflection of V/Q distribution

1978 ◽  
Vol 44 (2) ◽  
pp. 277-283 ◽  
Author(s):  
G. R. Neufeld ◽  
J. J. Williams ◽  
P. L. Klineberg ◽  
B. E. Marshall
Keyword(s):  
Quantitative Information ◽  
Inert Gas ◽  
The Mean ◽  
Log Normal ◽  
The Relationship ◽  
Log Normal Distribution ◽  
Direct Reflection ◽  
Direct Calculations ◽  
Difference Plot ◽  
Inert Gas Retention

A computer model was developed to study the relationship between ventilation-to-perfusion (V/Q) mismatch and the development of inert gas arterial-to-alveolar partial pressure differences (a-A differences). Increasing inhomogeneity of V/Q ratio is revealed directly as an increase in the a-A difference of each gas. The quantitative relationships between the Q vs. V/Q distribution and the fractional a-A difference solubility plot (a-A difference plot) were studied and described. These studies demonstrated that for log normally distributed V/Q ratios, the area under the a-A difference plot is linearly related to the log variance of the V/Q distribution and can be estimated directly from the values obtained from six gases. The maximum a-A difference occurs for a gas whose solubility is numerically equal to the mean V/Q. The effects of departure from log normality and multimodality are discussed. We conclude from these studies that quantitative information regarding the degree of inhomogeneity of V/Q for log normal distribution is available from direct calculations of inert gas retention and excretion data. Qualitative information is also available indicating the departure from log normality and the region toward which the distribution is skewed.

scholarly journals UNIVERSAL STRUCTURE OF THE PERSONAL INCOME DISTRIBUTION

Fractals ◽  
2001 ◽  
Vol 09 (04) ◽  
pp. 463-470 ◽  
Author(s):  
WATARU SOUMA
Keyword(s):  
Income Distribution ◽  
Asset Price ◽  
Mean Value ◽  
High Income ◽  
Personal Income ◽  
Middle Income ◽  
The Mean ◽  
Universal Structure ◽  
Log Normal ◽  
Log Normal Distribution

We investigate the Japanese personal income distribution in the high income range over the 112 years (1887–1998), and that in the middle income range over the 44 years (1955–1998). It is observed that the distribution pattern of the log-normal with power law tail is the universal structure. However, the indexes specifying the distribution differ from year to year. One of the index characterizing the distribution is the mean value of the log-normal distribution; the mean income in the middle income range. It is found that this value correlates linearly with the gross domestic product (GDP). To clarify the temporal change of the equality or inequality of the distribution, we analyze Pareto and Gibrat indexes, which characterize the distribution in the high income range and that in the middle income range, respectively. It is found for some years that there is no correlation between the high income and the middle income. It is also shown that the mean value of Pareto index equals to 2, and the change of this index is effected by the change of the asset price. From these analysis, we derive four constraints that must be satisfied by mathematical models.

Dust lidar ratios retrieved from the space-borne CALIOP measurements using the MODIS AOD as a constraint

2020 ◽  
Author(s):  
Sang-Woo Kim ◽  
Man-Hae Kim ◽  
Ali Omar
Keyword(s):  
Mean Values ◽  
Deep Blue ◽  
Source Regions ◽  
Modis Aod ◽  
Lidar Ratio ◽  
The Mean ◽  
Level 1 ◽  
Log Normal ◽  
Log Normal Distribution ◽  
Level 2

<p class="MDPI31text"><span lang="EN-US">Dust lidar ratios are retrieved by a synergetic use of CALIOP and MODIS products for 5 years from 2007 to 2011. The CALIOP level 1 total attenuated backscatter data is used for the retrieval and the CALIOP level 2 aerosol profile product is used to determine dust layers. Quality assured (QA > 1 for dark target ocean, QA = 3 for deep blue land) aerosol optical depth (AOD) data from the MODIS level 2 aerosol product is used as constraint. MODIS AOD retrievals and CALIOP attenuated backscatter profiles closer than 10 km from the center of MODIS pixel are defined as collocated measurements. Clouds are screened out for both CALIOP and MODIS. The retrieval is performed for the whole column of the atmosphere from 30 km to the surface adopting a constant lidar ratio of 30 sr for aerosols of clear air above the detected layers. The retrieved dust lidar ratios show a log-normal distribution with mean (median) values of 39.5 ± 16.8 (38.1) sr and 46.6 ± 36.3 (39.2) sr for ocean and land, respectively. The mean values are comparable to the value of 44 sr currently used in the CALIOP level 2 aerosol algorithm but the median values are relatively lower. There is a distinct regional variation in the retrieved dust lidar ratios. Dust lidar ratio is larger for the Saharan Desert (49.5 ± 36.8 sr) than the Arabian Desert (42.5 ± 26.2 sr), which is consistent with many previous studies. Dust aerosols transported to the Mediterranean Sea (44.4 ± 15.9 sr), Mid Atlantic (40.3 ± 12.4 sr) and Arabian Sea (37.5 ± 12.1 sr) show lower values compared with their source regions. An aging process of the long-range transported dust to remote ocean may be responsible for low lidar ratios. Dust lidar ratio over ocean in East Asia is 41.8 ± 27.6 sr is comparable with previous studies. Over Taklamakan and Gobi Deserts region the retrieved dust lidar ratios (35.5 ± 31.1 sr) show low values but still comparable with previous studies. Dust lidar ratios for Australia (35.4 ± 34.4 sr) are also relatively low compared with other regions. Although the mean AOD difference between CALIOP and MODIS is small (close to zero), the distribution of the AOD difference shows that the CALIOP AOD is biased low. However, when including clear air AOD for CALIOP, AODs from the two sensors become more comparable. A conclusion that can be drawn from this is that retrieving only for the detected layers in the CALIOP algorithm is one of the major reasons for lower AODs for CALIOP than MODIS. Lidar ratios retrieved in this study are strongly affected by MODIS AOD, because it is used as a constraint for the retrieval. </span></p>

scholarly journals Changes in numbers and heparin content of peritoneal fluid mast cells of growing rats measured by flow cytofluorometry.

1978 ◽  
Vol 26 (1) ◽  
pp. 14-21 ◽  
Author(s):  
G Berlin ◽  
L Enerbäck
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Flow Cytofluorometry ◽  
Growing Rats ◽  
Cell Counts ◽  
Peritoneal Mast Cells ◽  
Old Rats ◽  
The Mean ◽  
Log Normal ◽  
Log Normal Distribution

A cytofluorometric method, based on berberine staining of mast cell heparin, was used for flow cytofluorometric counting and heparin quantitation of mast cells in crude peritoneal suspensions of growing rats. The automatic flow cytofluorometric counting of mast cells correlated well with hemocytometer cell counts. The mean mast cell heparin content obtained by flow cytofluorometry showed good agreement with such obtained by cytofluorometry of microscopically identified mast cells. The number of peritoneal mast cells and the mean mast cell heparin content was found to increase as the animals grew older. The results of the microscope fluorometric measurements suggested that the heparin content was normally distributed within mast cell populations of both young and old rats. However, the heparin distributions obtained by flow cytofluorometry were often positively skewed but did not fulfill the condition of the log-normal distribution.

scholarly journals Estimating the mean and variance from the five-number summary of a log-normal distribution

2020 ◽  
Vol 13 (4) ◽  
pp. 519-531
Author(s):  
Jiandong Shi ◽  
Tiejun Tong ◽  
Yuedong Wang ◽  
Marc G. Genton
Keyword(s):  
Normal Distribution ◽  
Mean And Variance ◽  
The Mean ◽  
Log Normal ◽  
Log Normal Distribution

scholarly journals Divergent estimates of ratio between Na+-Ca2+ current densities in t-tubular and surface membranes of rat cardiomyocytes

2021 ◽  
Author(s):  
Michal Pásek ◽  
Jiří Šimurda ◽  
Markéta Bébarová ◽  
Georges Christé
Keyword(s):  
Normal Distribution ◽  
Measured Data ◽  
Asymmetric Distribution ◽  
Rat Cardiomyocytes ◽  
Adult Rat ◽  
Current Densities ◽  
The Mean ◽  
Log Normal ◽  
Reported Data ◽  
Log Normal Distribution

The ratio between Na+-Ca2+ exchange current densities in t-tubular and surface membranes of rat ventricular cardiomyocytes (JNaCa-ratio) estimated from electrophysiological data published to date yields strikingly different values between 1.7 and nearly 40. Possible reasons of such divergence were analysed by Monte-Carlo simulations assuming either normal or log-normal distribution of measured data. The confidence intervals CI95 of the mean JNaCa-ratios computed from the reported data showed an overlap of values between 1 and 3 and between 0.3 and 4.3 in the case of normal and log-normal distribution, respectively. Further analysis revealed that the high published values likely result from a large scatter of data due to transmural differences in JNaCa, dispersion of cell membrane capacitances and variability in incomplete detubulation. Taking into account the asymmetric distribution of measured data, reduction of mean current densities after detubulation, and substantially smaller CI95 of lower values of the mean JNaCa-ratio, the values between 1.6 and 3.2 may be considered as the most accurate estimates. This implicates that 40 to 60% of Na+-Ca2+ exchanger is located at the t-tubular membrane of adult rat cardiomyocytes.

scholarly journals Is Mean Time to Failure (MTTF) Equal to Mean Time of Life for Unrepairable Systems?

2021 ◽  
Vol 51 (1) ◽  
pp. 255-264
Author(s):  
Leszek Opyrchał
Keyword(s):  
Wigner Distribution ◽  
Time To Failure ◽  
Statistical Distributions ◽  
Chi Square ◽  
Mean Time To Failure ◽  
Reliability Parameters ◽  
The Mean ◽  
Log Normal ◽  
Mean Time ◽  
Log Normal Distribution

Abstract One of the most important reliability parameters is the mean time to failure (MTTF). It is widely accepted that the MTTF is equal to the mean time of life ET. This article shows that this is not necessarily true. Although for the most commonly used statistical distributions (such as exponential, Gaussian, chi-square, Fisher-Tippett distributions) the values of MTTF and ET are equal, this is not the case for the log-normal distribution. Similarity, some less commonly used distributions (such as Breit-Wigner distribution) may also require calculation adjustments resulting from MTTF ≠ ET. Ignoring this discrepancy, an erroneous MTTF value can be obtained.

X-ray particle-size broadening

1986 ◽  
Vol 42 (1) ◽  
pp. 6-13 ◽  
Author(s):  
S. Rao ◽  
C. R. Houska
Keyword(s):  
Particle Size ◽  
Normal Distribution ◽  
Variation Coefficient ◽  
Column Height ◽  
X Ray Diffraction ◽  
Diffraction Profile ◽  
X Ray ◽  
The Mean ◽  
Log Normal ◽  
Log Normal Distribution

X-ray diffraction profiles and Fourier coefficients are given for particles distributed according to experimentally verified size distributions. Calculations are based upon the log normal distribution of sphere diameters and intercept lengths in addition to a normal distribution of column heights. It is found that the diffraction profile is not sensitive to the fine details of the distribution but rather the mean column height and the column-height variation coefficient. Errors in particle-size determinations will result from an improper choice of the variation coefficient. Two simplified models are given that describe the diffraction profiles for a large range of variation coefficients.

Sign in / Sign up

Export Citation Format

Share Document