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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Letters in mathematical physics 35 (1995), S. 375-383 
    ISSN: 1573-0530
    Schlagwort(e): 46L55 ; 28D20 ; 82B10
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik , Physik
    Notizen: Abstract We present a rigorous computation of the dynamical entropyh of the quantum Arnold cat map. This map, which describes a flow on the noncommutative two-dimensional torus, is a simple example of a quantum dynamical system with optimal mixing properties, characterized by Lyapunov exponents ± 1n λ+, λ+ 〉 1. We show that, for all values of the quantum deformation parameter,h coincides with the positive Lyapunov exponent of the dynamics.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 257 (1989), S. 105-113 
    ISSN: 1432-0878
    Schlagwort(e): Insect nervous system ; Cholecystokinin-like peptide ; Immunohistochemistry ; Radioimmunoassay ; Aeschna cyanea (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Gastrin/cholecystokinin (gastrin/CCK)-like immunoreactivity has been detected in the brain, suboesophageal ganglion and corpora cardiaca of the larva of Aeschna cyanea by radioimmunoassay and immunohistochemistry, by use of two antisera raised against the sulfated (CCK-8S) and the unsulfated form (CCK-8NS) of the carboxyl terminal octapeptide. Numerous immunoreactive neurons were demonstrated in the protocerebrum (exclusive of optic lobes) and suboesophageal ganglion where 20 and 15 symmetrical clusters of reactive cells, respectively, were observed. Immunoreactive cells also occurred in the tritocerebrum, the optic lobes and the frontal ganglion. In the corpora cardiaca, gastrin/CCK-like material was found both within intrinsic cells and axon terminals. RIA measurements support the immunohistochemical results in so far as large amounts of gastrin/CCK-like material were detected in the brain, corpora cardiaca and suboesophageal ganglion complex. Both boiling water-acetic acid- and methanol-extraction procedures were performed. Comparisons of the results lead to the conclusion that a large part of the gastrin/CCK-like material occurs as small molecules. Immunohistochemical procedures performed on material fixed in a solution of picric acid-paraformaldehyde demonstrated differences in the immunoreactivity of the tested antisera. First, the immunohistochemical reaction was always more pronounced when the CCK-8NS antiserum was used instead of the CCK-8S antiserum, which may be interpreted by a lower affinity of the latter. In the second place, some neurons strongly stained by the CCK-8NS antiserum were only very faintly if at all stained by the CCK-8S antiserum, which may mean that different peptides or at least distinct forms of the same precursor are detected.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 240 (1985), S. 323-332 
    ISSN: 1432-0878
    Schlagwort(e): Mammalian-like peptides ; Insect midgut ; Immunohistochemistry ; Endocrine-cell ultrastructure ; Peptidergic and serotoninergic innervation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The midgut of Blaberus craniifer is principally made up of columnar epithelial cells which are derived from small regenerative cells found grouped in nidi. Between them, small sparsely granulated cells with clear cytoplasm can be observed lying on the basal lamina. Mainly based on the size, shape and texture of their secretory granules, at least ten types of such endocrine cells have been identified. Five cell types contain a uniform population of dense granules: (1) medium-sized, round to oval granules; (2) small elongated granules; (3) large irregular granules; (4) oval granules with a highly osmiophilic core; (5) oval, haloed granules. Five others are characterized by a heterogeneous population of granules: (6) small, round to oval, variably electron-dense granules; (7) oval medium-sized granules of variable electron density; (8) large irregular granules of variable electron density; (9) small dense granules and large vesicles with filamentous material; (10) small dense granules and very large pale vesicles. In addition, near the regenerative cells, large cells characterized by very large, irregular, dense granules (up to 4 μm), lack contact with the lumen, and reach the basal lamina only by slender cytoplasmic processes. Several antisera raised against mammalian peptides and amine were used to reveal axonal fibers and endocrine cells. Serotonin-like immunoreactivity is localized in a profuse innervation of the muscle layers that surround the epithelium, whereas cholecystokinin and methionine-enkephalin antisera stain a more moderate number of axonal fibers. Cholecystokinin-, methionine-enkephalin-, substance P-, vasoactive intestinal peptide-, somatoliberin-, and gonadoliberin-like immunoreactivities were detected in endocrine cells of the epithelium. While most of the cells appear pyramidal, oval, fusiform or bowl-shaped, and seem to lack contact with the lumen, cells reaching it have been detected reacting with antisera to cholecystokinin, substance P, vasoactive intestinal peptide, somatoliberin and gonadoliberin.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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