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  • 2020-2022
  • 1970-1974  (4)
  • 1972  (4)
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  • 2020-2022
  • 1970-1974  (4)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 81 (1972), S. 363-380 
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung An schwirrenden Kolibris (Amazilia fimbriata fluviatilis, mittleres Gewicht 5,7 g) wurden O2-Verbrauch, CO2-Produktion, Atemfrequenz, respiratorische Wasserabgabe und Flügelschlagfrequenz gemessen. Die Versuche wurden bei Temperaturen von 0–35 ° C durchgeführt. Der O2-Verbrauch im Plug bei Temperaturen über 20 ° C beträgt 4,1 ml O2/min= 43 ml O2/g·h, was das 14fache des Basalstoffwechsels ist. Bei Erniedrigung der Umgebungstemperatur nimmt der O2-Verbrauch kontinuierlich um etwa 6% je 10 ° C zu (Abb. 3). Es wird beim Schwirrflug eine weitgehende Substitution der thermoregulatorisch notwendigen Wärmeproduktion durch die bei der Kontraktion der Flugmuskeln entstehende Wärmemenge angenommen. Es wurde die Atemfrequenz mit rund 280/min bestimmt, das Atemzugvolumen mit 0,63 ml (BTS), die Ventilation mit 0,18 l/min (BTS) und die Sauerstoffausnutzung mit 2,2% errechnet. Die respiratorische Wärmeabgabe beträgt bei Temperaturen bis 20 ° C weniger als 20% der Wärmeproduktion, bei 35 ° C wurde das Maximum von 40% gemessen (Abb. 6). Bei trockener Luft macht die respiratorische Wasserabgabe 2,9–4,6% (0–20 ° C) bzw. rund 11% (bei 35 ° C) des Körpergewichtes pro Stunde aus. Bei 0 ° C gleichen sich Wasserproduktion durch Stoffwechselvorgänge und respiratorische Abgabe, bei allen anderen Temperaturen überwiegt die Abgabe: bei 35 ° C beträgt der Netto verlast 350% der Produktion.
    Notes: Summary In hovering hummingbirds (Amazilia fimbriata fluviatilis, mean weight 5.7 g) oxygen consumption, CO2 production, breathing frequency, respiratory water loss and wing frequency were measured at various environmental temperatures from 0 to 35 ° C. The oxygen consumption above 20 ° C reached 4.1 ml/min = 43 ml/g·hr, and was 14 times the calculated basal rate. Oxygen consumption increased about 6% for a 10 ° C fall in environmental temperature (Fig. 3). During flight the thermoregulatory heat production at low temperatures was largely substituted by the heat that is produced by contraction of the wing muscles. The respiratory frequency was estimated to be 280/min, the tidal volume 0.63 ml (BTS), the ventilation 0.18 1/min (BTS) and the oxygen utilization as 2.2%. The respiratory heat loss at temperatures of 20 ° C and below was less than 20% of the heat production, while at 35 ° C a maximum loss of 40% was reached (Fig. 6). In dry air at 0–20° C the water loss measured 2.9 to 4.5% of body weight per hour while at 35 ° C the loss was 11%. At 0 ° C the respiratory water loss and metabolic water production were equal, but at all other temperatures the loss exceeded production (at 35 ° C the loss exceeded production by 350%).
    Type of Medium: Electronic Resource
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  • 2
    Publication Date: 1972-07-01
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
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  • 3
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    Unknown
    In:  Other Sources
    Publication Date: 2011-08-16
    Description: Results of calculations concerning the emission of bremsstrahlung by electrons in the upper atmosphere and the penetration of this radiation to atmospheric depths of 3 to 10 g/sq cm, where it can be measured by balloon-borne detectors. The calculations take into account the multiple scattering and slowing down of electrons, and the multiple Compton scattering and photoelectric absorption of bremsstrahlung photons. Numerical data have been generated for electron beams incident onto the atmosphere with energies between 20 keV and 2 MeV, assuming wide-area precipitation and an incident angular distribution isotropic over the downward hemisphere. The results relate the number and energy spectrum of the incident electrons to the bremsstrahlung flux spectrum at balloon heights. The interpretation of some observed bremsstrahlung flux spectra is attempted.
    Keywords: SPACE SCIENCES
    Type: Journal of Atmospheric and Terrestrial Physics; 34; Jan. 197
    Format: text
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  • 4
    Publication Date: 2019-06-27
    Description: The penetration, diffusion and slowing down of electrons in a semi-infinite air medium has been studied by the Monte Carlo method. The results are applicable to the atmosphere at altitudes up to 300 km. Most of the results pertain to monoenergetic electron beams injected into the atmosphere at a height of 300 km, either vertically downwards or with a pitch-angle distribution isotropic over the downward hemisphere. Some results were also obtained for various initial pitch angles between 0 deg and 90 deg. Information has been generated concerning the following topics: (1) the backscattering of electrons from the atmosphere, expressed in terms of backscattering coefficients, angular distributions and energy spectra of reflected electrons, for incident energies T(o) between 2 keV and 2 MeV; (2) energy deposition by electrons as a function of the altitude, down to 80 km, for T(o) between 2 keV and 2 MeV; (3) the corresponding energy depostion by electron-produced bremsstrahlung, down to 30 km; (4) the evolution of the electron flux spectrum as function of the atmospheric depth, for T(o) between 2 keV and 20 keV. Energy deposition results are given for incident electron beams with exponential and power-exponential spectra.
    Keywords: PHYSICS, ATOMIC, MOLECULAR, AND NUCLEAR
    Type: NASA-TM-X-69898
    Format: application/pdf
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