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  • 1
    Electronic Resource
    Electronic Resource
    Filter-feeding ethology of benthic invertebrates (ascidians). IV. Pumping rate, filtration rate, filtration efficiency (1978)
    Springer
    Marine biology 48 (1978), S. 243-249 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A combination of a direct and an indirect method has been used for the first time in the study of filter-feeding in benthic invertebrates. Experiments over 12 h periods under constant temperature, pH, light and feeding conditions have been carried out with 3 species of ascidians: Ciona intestinalis (Linné, 1767); Phallusia mammillata (Cuvier, 1815) and Styela plicata (Lesueur, 1823). In C. intestinalis and P. mammillata, no pumping rhythm has been found; the water flow was constant for 12 h, except for some brief accidental interruptions. In S. plicata, the particular rhythm of spontaneous periodical contractions recorded during the experiment were related to gamete emission. The speed of water flow, which was fairly constant during recording, varied considerably during the 12 h period; these variations were generally related to modifications in the diameter of the cloacal siphon. The average speeds, in cm sec-1, lay between 5.7 and 9.5 for C. intestinalis, 5.2 and 19.4 for P. mammillata, and between 5.3 and 10.7 for S. plicata. Variations in the pumping-rate were small, oscillating around a mean value. In ml h-1 g-1 dry weight of organs these were 5,829 to 5,982 (mean=5,906) for C. intestinalis, 6,142 to 6,592 (mean=6,312) for P. mammillata, 1,0508 to 1,1505 (mean=1,0708) for S. plicata. Filtration was continuous without any particular rhythm; filtration rates in ml h-1 g-1 dry weight of organs varied between 4,244 and 4,418 (mean=4,331) for C. intestinalis, 4,620 and 4,960 (mean=4,779) for P. mammillata, 8,482 and 9,078 (mean=8,760) for S. plicata. The curves representing pumping and filtration were clearly parallel, indicating that filtration efficiency did not vary greatly during the course of an experiment; the rates obtained were 65 to 87% (mean=74%) for C. intestinalis, 66 to 88% (mean 76%) for P. mammillata, and 73 to 90% (mean=80%) for S. plicata. The slightly higher mean value in S. plicata is probably related to the higher complexity of the branchial apparatus of this species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00397151
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  • 2
    Electronic Resource
    Electronic Resource
    Filter-feeding ethology of benthic invertebrates (ascidians). V. Influence of temperature on pumping, filtration and digestion rates and rhythms in Phallusia mamillata (1978)
    Springer
    Marine biology 48 (1978), S. 251-259 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The influence of temperature has been studied simultaneously on the pumping, filtration, and digestion rates of Phallusia mammillata (Cuvier, 1815). Eighteen experiments were made between 7° and 25°C on 5 individuals. The average velocities of the water current varied between 3.37 and 9.65 cm sec-1 (maximum 34.90 cm sec-1). No recognizable rhythm emerged; pumping was continuous except at 7°C, where it soon ceased. Above 20°C, the curves were irregular and reflected the high sensitivity of the ascidian. The pumping rate was highest at 15°C (mean=5,788 ml h-1 g-1 dry weight of organs). At 10°C, the mean was 3,560; at 20°C, 2,629 ml h-1 g-1 dry weight of organs. At 20°C, the coefficients of variation displayed higher values, indicating a more irregular pumping at this temperature. Although there was no filtration rhythm, the variability of the results was higher at 20°C and above. As for pumping, maximum values were observed at 15°C (mean=4,286 ml h-1 g-1 dry weight of organs) decreasing with lower and higher temperatures, such decreases being more marked at the higher temperatures. Means were 352 ml h-1 g-1 dry weight of organs at 7°C; 2,935 at 10°C; 1,995 at 20°C; 973 at 25°C. The mean temperature coefficients for the filtration rates were: Q10 for 7° to 15°C=11.86, Q10 for 10° to 20°C=0,66, Q10 for 15° to 25°C=0.22. The filtering efficiency was fairly constant throughout an experiment; the pumping and filtration curves were in fact almost parallel. The filtering efficiency of the branchial sac was high (75 to 85%), with constant values at 10° and 15°C; it became smaller (59%) at 20°C, with a higher coefficient of variation. The digestion rate also displayed maximum values at 15°C (mean=5.47 mg of albumin equivalent 24 h-1 g-1 dry weight of organs). It was lower at 10°C (mean=3.60 mg) and reached its minimum at 20°C (mean=1.71 mg). The higher temperature affected the percentage of food utilization, which showed smaller values at 20°C (59%) than at 10°C (89%) and 15°C (87%).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00397152
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  • 3
    Electronic Resource
    Electronic Resource
    Filter-feeding ethology of benthic invertebrates (Ascidians). III. Recording of water current in situ — Rate and rhythm of pumping (1978)
    Springer
    Marine biology 45 (1978), S. 185-190 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Water current in 4 species of ascidians (Ascidia mentula Müller, 1776; Phallusia mammillata Cuvier, 1815; Styela plicata (Lesueur, 1823) and Microcosmus sabatieri Roule, 1885) has been recorded for the first time in situ with hot film probes. The mathematical treatment of probe calibration has allowed the evaluation of the characteristics of currents (minimal, maximal and average velocities) and the calculation of pumping rates. The method utilized yields qualitative and quantitative results: Pumping is continuous, and no particular rhythm shows up in the curves obtained. The velocity of the current does not change in the course of a recording, but it can vary from one experiment to another in the same individual; these variations are related to the variability of the diameter of the cloacal siphon rather than to a change in the rhythm of the ciliary activity. The average velocities are 3.42 cm sec-1 for A. mentula, 3.92 for P. mammillata, 3.30 for S. plicata and 3.79 for M. sabatieri. The pumping rates are fairly constant for the same individual. The means, expressed as ml x h-1 x g-1 organ dry weight are 3422 for A. mentula, 2070 for P. mammillata, 4892 for S. plicata and 3084 for M. sabatieri.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00390554
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  • 4
    Electronic Resource
    Electronic Resource
    Optimization of powder-diffraction identification (1976)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 9 (1976), S. 429-432 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: A mathematical model for X-ray powder-diffraction phase analysis is formulated and, based on this model, new identification criteria are established and the conditions under which a solution is optimal are discussed. The proposed concept is illustrated with a three-phase sample problem.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889876011862
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  • 5
    Electronic Resource
    Electronic Resource
    The chemistry of the minerals of the pyrope dunite from borehole T-7 near Staré (Bohemia) (1977)
    Springer
    Mineralogy and petrology 24 (1977), S. 205-219 
    Details
    ISSN: 1438-1168
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Description / Table of Contents: Zusammenfassung Die chemische Zusammensetzung der Primärminerale (Olivin, Orthopyroxen, Klinopyroxen und Pyrop) der Dunite aus der Bohrung T-7 bei Staré im Böhmischen Mittelgebirge (Böhmen) und diejenige der Minerale der Reaktionssäume um violetten Pyrop in diesen Gesteinen (nämlich Pyrop, Klinopyroxen, Cr-reicher Spinell und-an den Säumen — Orthopyroxen) wurde mit Elektronenmikrosonde-Analysen bestimmt. Aufgrund der Analysen aus der Literatur und der neuen werden die Zusammenhänge zwischen den Gesamtchemismen der Dunite und Lherzolithe mit demjenigen ihrer Minerale diskutiert. Im Vergleich zum Lherzolith enthalten der Dunit und alle seine Minerale relativ mehr Magnesium und Chrom, aber weniger Eisen, Aluminium und Titan. Es wird angenommen, daß diePT-Bildungsbedingungen der Symplektite in den Reaktionssäumen um Pyrop nicht sehr verschieden von denen der Minerale der Dunit-Matrix waren.
    Notes: Summary The chemical compositions of the primary minerals (olivine, orthopyroxene, clinopyroxene and pyrope) of dunites from borehole T-7 near Staré in the České středohoří Mountains (Bohemia) as well as those of the minerals forming coronas around violet pyrope in these rocks (i. e. pyrope, clinopyroxene, Cr-rich spinel, and—in the rims—orthopyroxene) were determined by electronmicroprobe analysis. The chemical relationships between the bulk composition of dunite and lherzolite and that of their constituent minerals are discussed on the basis of analyses from the literature and the new ones. In comparison to lherzolite, dunite and all its minerals contain more magnesium and chromium, but less iron, aluminum and titanium. ThePT conditions of the formation of the symplectites of the coronas around pyrope are considered not to be very different from those of the minerals of the dunite matrix.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01081128
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  • 6
    Electronic Resource
    Electronic Resource
    NMR-Untersuchung der Wasser/Methanol-Lösungen des Formaldehyds (1976)
    Springer
    Colloid & polymer science 254 (1976), S. 936-936 
    Details
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01775498
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  • 7
    Electronic Resource
    Electronic Resource
    Potential of pulsating point charge in warm isotropic plasma (1975)
    Springer
    Czechoslovak journal of physics 25 (1975), S. 51-56 
    Details
    ISSN: 1572-9486
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract An expression for the potential of a pulsating point charge in a warm isotropic plasma known from previous work is derived in an independent way. This approach offers a possibility to calculate the plasma response as a Laplace instead of Fourier integral and may give some insight even into problems without spherical symmetry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01589671
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  • 8
    Electronic Resource
    Electronic Resource
    Roots op the dispersion equation op a warm drifting plasma (1979)
    Springer
    Czechoslovak journal of physics 29 (1979), S. 589-590 
    Details
    ISSN: 1572-9486
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01600181
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  • 9
    Electronic Resource
    Electronic Resource
    Elastic properties of eclogite rocks from the Bohemian massif (1978)
    Springer
    Studia geophysica et geodaetica 22 (1978), S. 348-361 
    Details
    ISSN: 1573-1626
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences , Physics
    Notes: Summary Compressional velocity anistropy has been studied in detail at atmospheric pressure for 78 specimens of 23 types of eclogite rocks from the Bohemian massif. For nine of these rock types, compressional and shear velocities were measured as a function of pressure to750 MPa at room temperature. The velocity anisotropy for both compressional and shear waves is less than4% at high pressure. The velocities increase with increasing garnet content and decrease with increasing symplectitization. The Moldanubian eclogites have significantly higher velocities, on the average, than the eclogites from the Krušné hory crystalline complex, although the densities of both groups are comparable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02179277
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  • 10
    Electronic Resource
    Electronic Resource
    On sweeping frequency impedance measurements (1979)
    Springer
    Studia geophysica et geodaetica 23 (1979), S. 388-392 
    Details
    ISSN: 1573-1626
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences , Physics
    Notes: Summary The current spectral density I(щ) dependence on the width of the frequency band and sweep period is studied. The relation between the required accuracy of measurement an the optional parameters of the sweeping process is formulated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01633244
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