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  • Weitere Quellen  (34)
  • Taylor & Francis  (15)
  • Wiley-Blackwell  (8)
  • Cambridge University Press  (4)
  • Inst. f. Geophys., Ruhr-Univ. Bochum  (4)
  • Molecular Diversity Preservation International
  • Nature Publishing Group
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  • 2005-2009
  • 1990-1994  (34)
  • 1970-1974
  • 1991  (34)
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  • 1
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    Inst. f. Geophys., Ruhr-Univ. Bochum
    In:  Interner Bericht, Orsay, Inst. f. Geophys., Ruhr-Univ. Bochum, vol. 10, no. WS-693 7-83, pp. 139-140, (ISBN 3-933346-037)
    Publikationsdatum: 1991
    Schlagwort(e): Seismology ; Velocity analysis
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
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    Inst. f. Geophys., Ruhr-Univ. Bochum
    In:  Dissertation, Berichte Reihe A, Reykjavík, Inst. f. Geophys., Ruhr-Univ. Bochum, vol. 1034, no. 31, pp. 1-162, (ISBN 3-933346-037)
    Publikationsdatum: 1991
    Schlagwort(e): Laboratory measurements ; Rock mechanics ; Anisotropy ; Inhomogeneity ; Stress
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
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    Inst. f. Geophys., Ruhr-Univ. Bochum
    In:  Abstract, DGG-Tagung, Universität Frankfurt, Inst. f. Geophys., Ruhr-Univ. Bochum, vol. C 560, 183 pp., no. 70, pp. 16, (ISBN 3-933346-037)
    Publikationsdatum: 1991
    Schlagwort(e): Seismology ; Statistical investigations ; Velocity analysis ; Conference abstr. ; Muller
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  • 4
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    Inst. f. Geophys., Ruhr-Univ. Bochum
    In:  Dissertation, Berichte Reihe A, Rotterdam, Inst. f. Geophys., Ruhr-Univ. Bochum, vol. C 560, 183 pp., no. 32, pp. 205-211, (ISBN 3-933346-037)
    Publikationsdatum: 1991
    Schlagwort(e): Applied geophysics ; Borehole geophys. ; Borehole Televiewer ; Acoustics ; JSCHWEITZER ; FROTH
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  • 5
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    Taylor & Francis
    In:  Invertebrate Reproduction & Development, 19 (1). pp. 13-24.
    Publikationsdatum: 2017-02-01
    Beschreibung: Oogenesis in four commercial Caribbean sponge species, Hippospongia lachne, Spongia barbara, S. cheiris and S. graminea, was studied using light and transmission electron microscopy. Eggs and embryos develop asynchronously in localized endosomal nurseries of these viviparous and gonochoristic species. Statistical analyses of specific morphological characteristics of reproductive elements have unequivocally identified four specific stages in the process of oogenesis. Oogonia undergo mitotic division to produce primary oocytes. Meiotic division occurs producing secondary oocytes which are fertilized before zygotes undergo major growth by phagocytosis and the transfer of nutrients through cytoplasmic bridges. During cleavage of the zygote, umbilici form between embryos and nurse cell layers and these function in the transfer of symbiotic bacteria and other mesohyl substances from the maternal parent to the embryo. These symbionts were observed dispersed between blastomeres of all young and maturing embryos and between internal cells of cytodifferentiated parenchymella larvae. Extracellular transfer of symbiotic bacteria from maternal tissues to developing embryos has not been reported in any other viviparous invertebrate.
    Materialart: Article , PeerReviewed
    Format: text
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  • 6
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    Taylor & Francis
    In:  New Zealand Journal of Marine and Freshwater Research , 25 . pp. 275-282.
    Publikationsdatum: 2020-06-22
    Beschreibung: Before 1985, Martialia hyadesi (Cephalopoda: Ommastrephidae) in the Pacific Ocean was known only from the Eltanin Fracture Zone and Macquarie Island. A joint Japan‐New Zealand squid survey around New Zealand captured many immature ommastrephid squids. Gel electrophoresis confirmed the presence of immature M. hyadesi. Aspects of the external morphology are described. The distinctive tentacle club was evident in the smallest specimen examined, 19 mm dorsal mantle length (ML). Arm trabeculae were first evident in specimens of 40–50 mm ML. Immature squid were distributed around and southward of the Subtropical Convergence Zone. The presence of very small squid (〈 10 mm ML) indicated spawning on or near the Auckland Island Shelf.
    Materialart: Article , PeerReviewed
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  • 7
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    Wiley-Blackwell
    In:  Journal of Zoology, 224 (3). pp. 431-477.
    Publikationsdatum: 2020-07-17
    Beschreibung: Three specimens of the rare giant squid (genus Architeuthis, 18 nominal species) are described from the waters around southern Africa. Consideration of their internal and external morphology, including beaks, radula, statocyst and statolith give no reason to suppose that the three specimens do not pertain to the same species. A standardized data collection form and a summary of existing morphometric data are presented for the first time and the morphology and systematics of the genus are discussed. The value of various systematic characters is examined and certain guidelines are proposed, with an appeal for a more scientific approach to Architeuthis studies. Features of the internal anatomy, including the female reproductive tract, are described and illustrated and the beak dimensions are used to evaluate existing regression formulae for beak and body parameters. The statocyst and statolith are described and illustrated in full, the statolith for the first time, and are compared with those of other squids. The value of recent data from trawl-caught specimens, as well as indirect evidence, is cited to replace speculation in discussions on distribution and habitat. Our specimens suggest that the waters off the south-western coast of Africa may be one of the natural habitats of Architeurhis, during both feeding and spawning periods of the life cycle.
    Materialart: Article , PeerReviewed
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  • 8
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 71 (01). p. 47.
    Publikationsdatum: 2020-07-16
    Beschreibung: The presence of Stoloteuthis leucoptera in the Mediterranean is recorded on the basis of three specimens, including an adult male, caught by IKMT and by commercial otter-trawl in the Ligurian Sea. The hypothesis of a recent immigration is discussed. The list of Mediterranean cephalopods (Mangold Wirz, 1963; Torchio, 1968; Bello, 1986; Mangold & Boletzsky, 1987) includes the Sepiolidae of the subfamily Heteroteuthinae, whose members are supposed to be pelagic throughout their life cycle. Mangold Wirz (1963) recognizes in the Mediterranean fauna the unique species Heteroteuthis dispar, the other authors include H. atlantis Voss, which Voss himself (1955) reported at Messina. To this group may now be added Stoloteuthis leucoptera (Verrill, 1878) a species until now recorded in limited Atlantic areas. Verrill (1881) wrote “This species is an exceedingly beautiful one, when living, owing to the elegance and brilliancy of its colours and the gracefulness of its movements. In swimming it moves its fins in a manner analogous to the motion of the wings of a butterfly.”
    Materialart: Article , PeerReviewed
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  • 9
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    Taylor & Francis
    In:  Invertebrate Reproduction & Development, 19 (1). pp. 1-11.
    Publikationsdatum: 2017-02-01
    Beschreibung: Sexual reproductive cycles of a Florida, U.S.A., population of four Caribbean commercial sponge species, Hippospongia lachne, Spongia barbara, S. cheiris and S. graminea, were determined by analysis of tissue samples collected over a three-year period. Spermatogenesis in these species was studied using light and transmission electron microscopy. The production of male gametes occurs in cysts within the endosomal tissue of mature specimens. Reproductive elements within an individual cyst develop synchronously while development between cysts is asynchronous. All available evidence suggests that these species are dioecious. Spermatogonia differentiate directly from choanocytes in situ. All cells of the chamber lose their collars and flagella and undergo mitosis to produce primary spermatocytes, each possessing a single flagellum. The ratio of nucleus to cell diameter in these cells is almost double that of choanocytes. Circumstantial evidence suggests that primary spermatocytes undergo meiosis to produce four spermatids, but confirmational chromatid linkage figures are still lacking. The mature spermatozoa lack both intermediate segments and acrosomes. Male gametes displayed a bright yellow-white autofluorescence when excited with blue light (460–485 nm).
    Materialart: Article , PeerReviewed
    Format: text
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  • 10
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    Taylor & Francis
    In:  South African Journal of Marine Science, 10 (1). pp. 193-201.
    Publikationsdatum: 2020-05-26
    Beschreibung: Squid on their spawning grounds feed mainly at night when they are more dispersed. In all, 28,5 per cent of squid sampled at night had food in their stomachs, whereas only 6,7 per cent of those collected by day had food. Most stomachs contained only a single prey species (90,8% of those analysed). Teleosts dominated the prey of squid collected at night (58%M), followed by crustaceans (25%), polychaetes (9%) and cephalopods (3%). By day the prey was dominated by cephalopods (61%), followed by teleosts (20%), crustaceans (14%) and polychaetes (2%). Bregmaceros sp. was the most frequently identified teleost, Loligo vulgaris reynaudii (cannibalism) the dominant cephalopod, ?Betaeus sp. (Alpheidae; pieces of coral were also found) the commonest crustacean and Nereis sp. the commonest polychaete. There were seasonal differences in the diet too: squid caught during summer seemed to have similar proportions of the four main prey components. Also, the incidence of feeding was higher than in winter. There were, however, no significant differences in stomach mass expressed as a percentage of body mass between day and night nor between season nor between sexes. The average stomach mass of all samples was 0,6 per cent of body mass, less than on the feeding grounds, where it is generally about 2 per cent.
    Materialart: Article , PeerReviewed
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