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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 66 (1970), S. 190-200 
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Investigations in 10 species showed that respiration of birds in flight is usually co-ordinated with wing beats, but the co-ordination is not obligatory. Respiration synchronous with wing beats (1∶1 co-ordination) was found only in pigeons and crows, the other species exhibited one of 11 other types of co-ordination. Quails, ducks and pheasants, birds with relatively high wing beat frequencies (with relatively small wings) showed a 5∶1 co-ordination. Within species, and even during a flight the type of co-ordination changed, and simultaneously there were sudden changes in the respiration frequency. For the most part, the beginning of inspiration was linked with the (end of) upstroke and the beginning of expiration with the end of downstroke.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 66 (1970), S. 201-214 
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pulmonary ventilation (tidal volume, frequency) and oxygen content of expired air were measured in separate flights for 3 species of birds — Evening Grosbeak (Hesperiphona vespertina), Ring-billed Gull (Larus delawarensis), and Black Duck (Anas rubripes). Heart rate was measured in flight or immediately after landing in 12 species. Respiratory frequency and tidal volume were greater in flight than during rest. As the O2 content of expired air did not change appreciably, the increase in O2 consumption was similar to the increase in ventilation and averaged more than 10 times basal. The influence of body weight on metabolism during flight was similar to that previously observed under basal conditions. Heart rates during flight (10 species), immediately after landing (12 species), and maximal rates from various authors (15 species) were in close agreement, and were 2–4 times as high as during rest. The heart rate decreased with increasing body weight according to the equation HRf=25.1 BW−0.16 (HR per sec, BW in g). In flight there was much less variation and there was a smaller decrease with increasing weight than during rest. Although the estimated stroke volume and heart size appear larger in birds, the ratio of these functions was similar to that in mammals.
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  • 3
    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%).
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Naturwissenschaften 61 (1974), S. 407-407 
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 5 (1994), S. 622-627 
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: The interaction between blood and an artificial surface results in the activation of complement and can lead to extensive inflammatory reactions. In vitro work was undertaken to validate a system of assays to evaluate the complement activation of a candidate biomaterial by comparing its capacity of activation with that of reference biomaterials. The biomaterials tested were cellulose acetate, cellulose dialysis tubing, low density polyethylene, polydimethylsiloxane and AN69. Complement activation was assessed using ELISA for iC3b, C3a and Factor Bb. Results showed that (1) iC3b measurements may underestimate complement activation, (2) the presence of Bb in plasma or serum was a reliable indicator of complement activation, (3) measurements of C3a are of interest but are difficult, (4) adsorption or/and binding of complement proteins occured on the surface. Evaluation of complement activation for a biomaterial should include the assessment of the fluid phase (in serum or plasma) as well as the bound phase (on the surface of the biomaterial) of complement.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 12 (1993), S. 825-828 
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 51 (1990), S. 33-39 
    ISSN: 1573-5060
    Keywords: Triticum aestivum ; wheat ; photosynthesis ; chlorophyll fluorescence ; harvest index ; biological yield ; economic yield ; short straw ; dwarfism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Improvements in bread wheat productivity have been related to changes in plant morphology and function associated with a large increase in the harvest index for a more or less constant biological yield. The appearance of short genotypes possessing dwarfism genes may modify markedly the objectives of breeding as the upper limits of the harvest index are approached. The aim of the investigations presented here was to identify some contrasts between short and tall genotypes in terms of the physiological characteristics associated with grain yield, so as to orientate more efficiently the selection of genotypes, with or without dwarfism genes, for productivity. Various parameters of flag leaf functioning (photosynthesis rate, chlorophyll fluorescence index, leaf area duration) were related to the biological and economic yields and the harvest index for two groups of genotypes that were differentiated by their height. For all genotypes, the relationships between the various traits and the grain yield were difficult to ascertain. For the tall genotypes without dwarfism genes, the classical relationships between grain yield, harvest index, flag leaf area duration and net photosynthesis rate were confirmed. Moreover, the rate of chlorophyll fluorescence decrease (Rfd) during the slow Kautsky kinetics phase, which is representative of the leaf photosynthesis at low light, was found to be an excellent marker of economic yield. Chlorophyll fluorescence decrease was closely related to grain yield and also with other factors that are known to be important in its expression (harvest index, flag leaf area duration). In very short genotypes, the biological yield and directly related factors (leaf area, plant height) were the main parameters associated with economic yield, since the harvest index had approached its upper limit. The selection of short genotypes must therefore maintain the biological yield through an increase in the size of the aerial organs to counterbalance the decrease in height.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of scientific computing 7 (1992), S. 197-228 
    ISSN: 1573-7691
    Keywords: Optimization ; gradient methods ; global convergence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract The idea of hierarchical gradient methods for optimization is considered. It is shown that the proposed approach provides powerful means to cope with some global convergence problems characteristic of the classical gradient methods. Concerning global convergence problems, four topics are addressed: The “detour” effect, the problem of multiscale models, the problem of highly ill-conditioned objective functions, and the problem of local-minima traps related to ambiguous regions of attractions. The great potential of hierarchical gradient algorithms is revealed through a hierarchical Gauss-Newton algorithm for unconstrained nonlinear least-squares problems. The algorithm, while maintaining a superlinear convergence rate like the common conjugate gradient or quasi-Newton methods, requires the evaluation of partial derivatives with respect to only one variable on each iteration. This property enables economized consumption of CPU time in case the computer codes for the derivatives are intensive CPU consumers, e.g., when the gradient evaluations of ODE or PDE models are produced by numerical differentiation. The hierarchical Gauss-Newton algorithm is extended to handle interval constraints on the variables and its effectiveness demonstrated by computational results.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Acta mathematica 132 (1974), S. 13-51 
    ISSN: 1871-2509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
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  • 10
    Publication Date: 1974-09-01
    Print ISSN: 0028-1042
    Electronic ISSN: 1432-1904
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Published by Springer
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