The High Altitude Sampling Program. Volume 2A. Results of Filter Analysis (Less Table 4.3 and Flight Cross-Sections).

1961 ◽  
Author(s):  
James P. Friend ◽  
Herbert W. Feely ◽  
Philip W. Krey ◽  
Jerome Spar ◽  
Alan Walton
Keyword(s):  
High Altitude ◽  
Cross Sections ◽  
Sampling Program ◽  
Filter Analysis

Brain tissue pH and ventilatory acclimatization to high altitude

1992 ◽  
Vol 72 (1) ◽  
pp. 58-63 ◽  
Author(s):  
S. V. Goldberg ◽  
R. B. Schoene ◽  
D. Haynor ◽  
B. Trimble ◽  
E. R. Swenson ◽  
...  
Keyword(s):  
High Altitude ◽  
Cross Sections ◽  
Human Subjects ◽  
Resonance Spectroscopy ◽  
Intracellular Acidosis ◽  
Arterial Blood Gas ◽  
Arterial Blood ◽  
Before And After ◽  
Brain Ph ◽  
Gas Measurements

31P nuclear magnetic resonance spectroscopy (31P-NMRS) was performed on brain cross sections of four human subjects before and after 7 days in a hypobaric chamber at 447 Torr to test the hypothesis that brain intracellular acidosis develops during acclimatization to high altitude and accounts for the progressively increasing ventilation that develops (ventilatory acclimatization). Arterial blood gas measurements confirmed increased ventilation. At the end of 1 wk of hypobaria, brain intracellular pH was 7.023 +/- 0.046 (SD), unchanged from preexposure pH of 6.998 +/- 0.029. After return to sea level, however, it decreased to 6.918 +/- 0.032 at 15 min (P less than 0.01) and 6.920 +/- 0.046 at 12 h (P less than 0.01). The ventilatory response to hypoxia increased [from 0.35 +/- 0.11 (l/min)/(-%O2 saturation) before exposure to 0.69 +/- 0.19 after, P = 0.06]. Brain intracellular acidosis is probably not a supplemental stimulus to ventilatory acclimatization to high altitude. However, brain intracellular acidosis develops on return to normoxia from chronic hypoxia, suggesting that brain pH may follow changes in blood and cerebrospinal fluid pH as they are altered by changes in ventilation.

scholarly journals Borehole logging with an eight-arm caliper–inclinometer probe

2006 ◽  
Vol 52 (178) ◽  
pp. 381-388 ◽  
Author(s):  
Aurel Schwerzmann ◽  
Martin Funk ◽  
Heinz Blatter
Keyword(s):  
High Altitude ◽  
Cross Sections ◽  
Vertical Direction ◽  
Swiss Alps ◽  
Strain Rates ◽  
Mathematical Methods ◽  
Borehole Logging ◽  
Vertical Strain

AbstractA newly designed eight-arm caliper–inclinometer probe for borehole logging is presented. The caliper sounding gives eight points of cross-sections of the borehole at 1 cm intervals along its axis. Regression circles and ellipses are calculated and used as obvious hypotheses to be tested in order to obtain information on strain rates in the horizontal planes and isotropic or anisotropic borehole closure. The scratching of identifiable marks into the wall of the borehole enables material displacement to be tracked, in particular in the vertical direction, thus providing information for determining vertical strain rates along the borehole. Measurements in two boreholes drilled on high-altitude glaciers in the Swiss Alps are used to demonstrate both the potential and the limitations of the probe and of the mathematical methods presented.

Are sex ratios of larval alpine newts (Mesotriton alpestris) biased in high-altitude spawning sites with different temperature regimes?

2009 ◽  
Vol 30 (3) ◽  
pp. 389-399 ◽  
Author(s):  
Robert Schabetsberger ◽  
Helmut Grabherr ◽  
Marc Sztatecsny
Keyword(s):  
Sex Determination ◽  
High Altitude ◽  
Cross Sections ◽  
Sex Ratios ◽  
Adult Males ◽  
Breeding Sites ◽  
Temperature Regimes ◽  
Significant Divergence ◽  
Alpine Newt ◽  
Spawning Sites

AbstractAmphibians generally have genetic sex determination which should lead to equal sex ratios. However, populations of the alpine newt (Mesotriton alpestris) from cold, high-altitude breeding sites in the Austrian Alps showed strongly female-biased sex ratios of up to 3.7 females to 1 male over 6 years. Temperature dependent sex determination has therefore been considered as possible reason to explain the observed skews. To investigate if a female excess already exists during gonadal differentiation of M. alpestris larvae before metamorphosis, we assessed larval sex ratios in high-altitude spawning sites with different temperature regimes. The sex was determined by histological analyses of cross sections of the gonads. In no case a significant divergence from a 1:1 sex ratio was found. Based on these results and previous karyological, skeletochronological, and ecological work we conclude that higher mortality rates of adult males are the most plausible explanation for the female excess in high-altitude populations of alpine newts. However, future studies should focus on the development of sex-specific genetic markers to allow early determination of gender in embryos and larvae.

Contrast of Filament Bright Rims

1994 ◽  
Vol 144 ◽  
pp. 365-367
Author(s):  
E. V. Kononovich ◽  
O. B. Smirnova ◽  
P. Heinzel ◽  
P. Kotrč
Keyword(s):  
High Altitude ◽  
Line Profile ◽  
Line Center ◽  
Magnetic Structures ◽  
The Mean

AbstractThe Hα filtergrams obtained at Tjan-Shan High Altitude Observatory near Alma-Ata (Moscow University Station) were measured in order to specify the bright rims contrast at different points along the line profile (0.0; ± 0.25; ± 0.5; ± 0.75 and ± 1.0 Å). The mean contrast value in the line center is about 25 percent. The bright rims interpretation as the bases of magnetic structures supporting the filaments is suggested.

Analysis of STEM micrographs of thick objects

1978 ◽  
Vol 36 (2) ◽  
pp. 106-107
Author(s):  
S. Golladay
Keyword(s):  
Inelastic Scattering ◽  
Multiple Scattering ◽  
Mass Distribution ◽  
Cross Sections ◽  
Phase Contrast ◽  
Image Point ◽  
Contrast Effects ◽  
Total Cross Sections ◽  
Elastic And Inelastic Scattering

The theory of multiple scattering has been worked out by Groves and comparisons have been made between predicted and observed signals for thick specimens observed in a STEM under conditions where phase contrast effects are unimportant. Independent measurements of the collection efficiencies of the two STEM detectors, calculations of the ratio σe/σi = R, where σe, σi are the total cross sections for elastic and inelastic scattering respectively, and a model of the unknown mass distribution are needed for these comparisons. In this paper an extension of this work will be described which allows the determination of the required efficiencies, R, and the unknown mass distribution from the data without additional measurements or models. Essential to the analysis is the fact that in a STEM two or more signal measurements can be made simultaneously at each image point.

Clean Electron Microscope Substrate Films Used for Micrometeorite Collection and Study

1967 ◽  
Vol 25 ◽  
pp. 366-367
Author(s):  
D. M. Davies ◽  
R. Kemner ◽  
E. F. Fullam
Keyword(s):  
Thin Film ◽  
Electron Microscope ◽  
High Altitude ◽  
Amyl Acetate ◽  
Temperature Variations ◽  
Film Forming ◽  
Film Specimen ◽  
Particulate Contaminants

All serious electron microscopists at one time or another have been concerned with the cleanliness and freedom from artifacts of thin film specimen support substrates. This is particularly important where there are relatively few particles of a sample to be found for study, as in the case of micrometeorite collections. For the deposition of such celestial garbage through the use of balloons, rockets, and aircraft, the thin film substrates must have not only all the attributes necessary for use in the electron microscope, but also be able to withstand rather wide temperature variations at high altitude, vibration and shock inherent in the collection vehicle's operation and occasionally an unscheduled violent landing.Nitrocellulose has been selected as a film forming material that meets these requirements yet lends itself to a relatively simple clean-up procedure to remove particulate contaminants. A 1% nitrocellulose solution is prepared by dissolving “Parlodion” in redistilled amyl acetate from which all moisture has been removed.

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