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  • 1
    Electronic Resource
    Electronic Resource
    A circadian rhythm in RNA in the dinoflagellate,Gonyaulax polyedra (1983)
    Springer
    Journal of comparative physiology 151 (1983), S. 207-213 
    Details
    ISSN: 1432-136X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The total RNA in stationary phase cultures of the dinoflagellate,Gonyaulax polyedra, in continuous light showed a well-defined circadian rhythm, as measured by the fluorescence of cells stained with acridine orange. The maximum RNA was found at CT 18 and was followed by a sharp drop in RNA content. The rhythm in RNA content could be phase-shifted by light in the same way as the rhythm in bioluminescence. Ribosomal RNA synthesis, as measured by the incorporation of32P into extracted RNA, was also rhythmic. New RNAs appeared at CT 18, as shown by acrylamide/agarose gel electrophoresis. Three to four hours later these RNAs had disappeared. These findings suggest a role of transcription in the expression of circadian rhythmicity inGonyaulax.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00689920
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  • 2
    Electronic Resource
    Electronic Resource
    Untersuchungen zur Struktur von LP-UP-Harzsystemen (1977)
    Springer
    Colloid & polymer science 255 (1977), S. 1145-1155 
    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
    Description / Table of Contents: Summary For the sheet moulding and bulk moulding technique, the use of low-shrink UP resins is on the increase. The morphological structure of these low profile systems is revealed by means of electron micrographs of fracture surfaces as well as ultrathin sections, which for the first time allow a coherent interpretation of the differing mechanisms of shrinkage compensation as a function of the thermoplasts added (cellulose acetobutyrate, polyvinyl acetate, polymethylmethacrylate, polyethylene, polystyrene).
    Notes: Zusammenfassung Je nach Wirkungsmechanismus der Schwundkompensation können die verschiedenen LP-Harzsysteme in 2 Gruppen eingeteilt werden: a) Bei celluloseacetobutyrathaltigen, polyvinylacetathaltigen und polymethylmethacrylathaltigen Systemen bewirken die zugesetzten Thermoplaste eine teilweise Phasenumkehr während der Härtung und damit Emulgierung der UP-Harzphase; es bilden sich stark versinterte Aggregate von kleinen Harzkugeln, deren mehr oder minder dichte Packung eine entsprechende Hohlraumstruktur entstehen 1äßt, die für den Schwundausgleich verantwortlich ist. Da die Durchmesser der Harzkugeln in der Größenordnung der Lichtwellenlänge liegen, tritt starke Lichtstreuung auf (Weißeffekt), die Ursache für die schlechte Einfärbbarkeit dieser Produkte ist. b) Bei polyäthylenhaltigen und polystyrolhaltigen Systemen diffundiert bei der Aushärtung das gelöste Styrol aus den Thermoplastkugeln in die umgebende UP-Harzmatrix und reagiert dort. Die in den Thermoplast-Teilchen zurückbleibenden Mikrohohlräume vereinigen sich bei den großen Teilchen — durch die Oberflächenspannung bedingt — meist zu einem zentralen Hohlraum. Bei den kleineren Thermoplasteinschlüssen sowie in den Randzonen der großen Teilchen tritt eine Phasenumkehr unter Bildung perlartiger Strukturen ein. Die großen, nur geringe Lichtstreuung zeigenden Hohlräume sind auch der Grund für die relativ gute Einfärbbarkeit dieser Systeme. Diese Aufklärung der morphologischen Struktur von LP-Systemen und die daraus abgeleiteten Vorstellungen über die Vorgänge bei der Schwundkompensation sind die Grundlage für die weitere gezielte Verbesserung und Optimierung dieser technisch bedeutsamen Produkte. Die Ergebnisse an praxisnahen LP-UP-Harzsystemen (mit MgO-Eindickung und Glasfaserverstärkungen) bilden Gegenstand einer weiteren Arbeit (14).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01447582
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  • 3
    Electronic Resource
    Electronic Resource
    Preparation of small α-iron particles from an amorphous Fe91Zr9 alloy (1989)
    Springer
    Catalysis letters 3 (1989), S. 191-195 
    Details
    ISSN: 1572-879X
    Keywords: Iron ; zirconium ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Small α-iron particles with diameter less than 10 nm and enlarged lattice constant have been obtained by low temperature oxidation and reduction of an amorphous Fe91Zr9 alloy.In-situ X-ray diffraction has been used to study the transformation of the alloy at 300 °C which is far below the crystallization temperature. Scanning electron microscopy showed that the reacted sample consisted mainly of aggregates of small iron particles. This might offer a promising method for the effective preparation of heterogeneous catalysts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00763728
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  • 4
    Electronic Resource
    Electronic Resource
    Bivariate segment approximation and splines (1996)
    Springer
    Advances in computational mathematics 6 (1996), S. 25-45 
    Details
    ISSN: 1572-9044
    Keywords: Bivariate approximation ; segment approximation ; bivariate splines ; functionals ; 41A15 ; 41A63 ; 65D07
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract The problem to determine partitions of a given rectangle which are optimal for segment approximation (e.g., by bivariate piecewise polynomials) is investigated. We give criteria for optimal partitions and develop algorithms for computing optimal partitions of certain types. It is shown that there is a surprising relationship between various types of optimal partitions. In this way, we obtain good partitions for interpolation by tensor product spline spaces. Our numerical examples show that the methods work efficiently.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02127694
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  • 5
    Electronic Resource
    Electronic Resource
    Die mechanische Relaxation in Eis-NH4F-Mischkristallen (1959)
    Springer
    The European physical journal 157 (1959), S. 266-274 
    Details
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Zusammenfassung Ein Verfahren zur Züchtung von Eis-NH4F-Mischeinkristallen wird beschrieben. Die mechanische Relaxation dieser Kristalle bei Konzentrationen von 1,4 · 10−4 und 5,4 · 10−6 Gewichtsteilen NH4F im Temperaturbereich von 0° C bis −120 °C und im Frequenzgebiet von 0,5 bis 6 kHz für zwei Verformungsarten wird gemessen. Der schon beim reinen Eis beobachtete und gedeutete einfache Relaxationsprozeß tritt hier mit zwei verschiedenen Aktivierungsenergien (13,4 und 2,3 (kcalMol) auf.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02055755
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  • 6
    Electronic Resource
    Electronic Resource
    Rotifer populations in plankton communities: Energetics and life history strategies (1995)
    Springer
    Cellular and molecular life sciences 51 (1995), S. 437-453 
    Details
    ISSN: 1420-9071
    Keywords: Food quality ; food quantity ; competition to cladocerans ; predation ; body size ; rmax/Ks-strategy ; bottom-up control ; top-down control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Rotifers play an important role in many freshwater plankton communities. The populations are controlled from ‘bottom-up’ depending on different food quantities and qualities. As threshold food levels for rotifers are higher than for cladocerans they are often outcompeted when food concentrations are lowered by the clearance activity of cladocerans. Rotifers also are controlled from ‘top-down’ by predators, especially by copepods, by instars ofChaoborus and by predatory rotifers. Mechanical interference by daphnids is considered here as a special case of ‘predation’. Different defense mechanisms are discussed. At the cost of higher food concentrations (high Ks-food levels) rotifers may exhibit high maximum growth rates (rmax) and short times for their population development. This ability increases with rotifer body size. Within this taxonomic unity, therefore, different life history strategies have developed. These strategies may be characterized by the rmax/Ks-model presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02143197
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  • 7
    Electronic Resource
    Electronic Resource
    Dünnschichtchromatographischer Nachweis der Aminosäuren im Urin (1963)
    Springer
    Cellular and molecular life sciences 19 (1963), S. 213-217 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Urinary amino acids are converted into DNP-derivatives. Extraction by organic solvents yields both ether- and acid-soluble DNP-derivatives in a form suitable for separation and identification by thin-layer chromatography. Solvent systems and techniques for the detection of 35 urinary constituents are described. The method is applicable to the qualitative analysis of other biological fluids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02172322
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  • 8
    Electronic Resource
    Electronic Resource
    Spline functions of negative degree (2000)
    Springer
    Calcolo 37 (2000), S. 125-137 
    Details
    ISSN: 1126-5434
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract: In a recent series of papers (see Goldman [1–3]), B-splines of negative degree were introduced and partially investigated. The main purpose of the present paper is to continue and to extend these investigations. In the first part, we look more deeply onto the negative degree B-splines; we present an explicit representation for them, as well as a degree elevation formula; this solves a problem posed in [3]. Moreover, in the second part we look (probably for the first time in the literature) at the structure of the space of negative degree spline functions, spanned by the negative degree B-splines. As a main result here, we obtain a truncated power function representation of these splines.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100920070005
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  • 9
    Electronic Resource
    Electronic Resource
    A contour integral representation of linear extrapolation methods (1989)
    Springer
    Numerische Mathematik 55 (1989), S. 477-480 
    Details
    ISSN: 0945-3245
    Keywords: AMS(MOS):65B05 ; CR: G.1.D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary Extrapolation methods are well-known to be very efficient tools for the acceleration of the convergence of certain sequences of numbers or functions, cf. [2, 3, 4, 8, 9]. In this note we present a representation of linear extrapolation procedures in terms of complex contour integrals. For the proof we make use of a complete characterization of these procedures as linear functionals, which is itself of some interest and can be found, for example, in [2] or [8].
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01396050
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  • 10
    Electronic Resource
    Electronic Resource
    Asymptotic expansions and acceleration of convergence for higher order iteration processes (1991)
    Springer
    Numerische Mathematik 59 (1991), S. 529-540 
    Details
    ISSN: 0945-3245
    Keywords: 65B05 ; 40A25
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary We analyze the convergence behavior of sequences of real numbers {x n }, which are defined through an iterative process of the formx n :=T(x n −1), whereT is a suitable real function. It will be proved that under certain mild assumptions onT, these numbersx n possess an asymptotic (error) expansion, where the type of this expansion depends on the derivative ofT in the limit point $$\xi : = \mathop {\lim }\limits_{n \to \infty } x_n $$ ; this generalizes a result of G. Meinardus [6]. It is well-known that the convergence of sequences, which possess an asymptotic expansion, can be accelerated significantly by application of a suitable extrapolation process. We introduce two types of such processes and study their main properties in some detail. In addition, we analyze practical aspects of the extrapolation and present the results of some numerical tests. As we shall see, even the convergence of Newton's method can be accelerated using the very simple linear extrapolation process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01385794
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