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  • 1985-1989  (2)
  • 1980-1984  (1)
  • 1925-1929
  • 1915-1919
  • 1900-1904
  • Bootettix  (1)
  • Cell & Developmental Biology  (1)
  • Columbite  (1)
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Material
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  • 1985-1989  (2)
  • 1980-1984  (1)
  • 1925-1929
  • 1915-1919
  • 1900-1904
Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Exsolution intergrowths of titanian ferrocolumbite and niobian rutile from the Weinebene Spodumene Pegmatites, Carinthia, Austria (1989)
    Springer
    Mineralogy and petrology 40 (1989), S. 197-206 
    Details
    ISSN: 1438-1168
    Keywords: Tantalum ; Niobium ; Titanium ; Columbite ; Rutile ; Mineralogy ; Geochemistry ; Pegmatite ; Austria ; Ostalpen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Description / Table of Contents: Zusammenfassung Titan-Ferrocolumbit ist ein seltenes Akzessorium in den Spodumenpegmatiten der Weinebene, Kärnten, Österreich. Er enthält entmischten niobhaltigen Rutil und selten Einschlüsse von möglicherweise primärem Zinnstein. Die Zusammensetzung des TitanFerrocolumbits ist relativ homogen und weist die folgenden Elementverhältnisse auf. Mn/(Mn + Fe) 0,24 – 0,33, Ta/(Ta + Nb) 0,09 – 0,13 (Atomverhältnisse) und 0,47 – 0,88 Ti pro 12 Kationen (2,7 - 5,0Gew.%TiO2). Natürlich auftretende Kristalle sind strukturell merklich ungeordnet und erlangen durch Erhitzen einen höheren Ordnungsgrad. Die Mn/(Mn + Fe) sowie Ta/(Ta + Nb) Verhältnisse des niobhaltigen Rutil betragen 0,00 – 0,04 bzw. 0,26 – 0,38. Der niobhaitige Rutil ist im Vergleich zu Mn- und Nb-führendem Ferrocolumbit an Fe, Ta, Ti und Sn angereichert.—Die Seltenheit von Nb, Ta-Oxiden in den spodumenführenden Pegmatiten der südlichen Ostalpen steht in Übereinstimmung mit ihrer Zugehörigkeit zum Albit-Spodumen Typ der selten-Element-führenden Pegmatite (rare-element pegmatites).
    Notes: Summary Titanian ferrocolumbite is a rare accessory mineral in the spodumene-bearing pegmatites at Weinebene, Carinthia, Austria. It contains abundant exsolved niobian rutile and scarce inclusions of cassiterite that may be primary. The titanian ferrocolumbite is relatively homogeneous with Mn/(Mn + Fe) 0.24–0.33, Ta/(Ta + Nb) 0.09–0.13 (atomic ratios) and 0.47–0.88 Ti per 12 cations (2.7–5.0 wt.% TiO2). Natural specimens are considerably disordered but become more ordered on heating. Niobian rutile has Mn/(Mn + Fe) 0.00–0.04 and Ta/(Ta + Nb) 0.26–0.38; it concentrates Fe, Ta, Ti and Sn relative to the Mn- and Nb-enriched ferrocolumbite. The overall scarcity of Nb, Ta-oxide minerals in the spodumene-bearing pegmatites of southern Ostalpen conforms to their general features ranking them with the albite-spodumene type of rare-element pegmatites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01164489
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  • 2
    Electronic Resource
    Electronic Resource
    Chemical aspects of host-plant specificity in threeLarrea-feeding grasshoppers (1988)
    Springer
    Journal of chemical ecology 14 (1988), S. 561-579 
    Details
    ISSN: 1573-1561
    Keywords: Creosote bush ; Larrea ; nordihydroguaiaretic acid ; grasshoppers ; monophagy ; Bootettix ; Ligurotettix ; Cibolacris ; Orthoptera ; Acrididae ; host selection ; feeding deterrence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The host-selection behavior of three species of grasshopper feeding on creosote bush,Larrea tridentata, in southern California was investigated. The species wereBootettix argentatus, which is monophagous;Ligurotettix coquilletti, oligophagous; andCibolacris parviceps, polyphagous. The monophagous species is stimulated to bite by nordihydroguaiaretic acid (NDGA), a compound that is characteristic of the host plant and that may comprise up to 10% of the dry weight of the leaf. Host specificity ofB. argentatus is enhanced by deterrent responses to compounds present in the surface waxes of all non-host-plant species. Both the oligophagous and polyphagous species are deterred by NDGA at naturally occurring concentrations. Their association withLarrea is probably based on tolerance of the plant chemicals rather than on dependence on specific chemicals. Factors other than the chemistry of the plant probably also contribute to the specificity ofB. argentatus andL. coquilletti.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01013907
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Ultrastructural changes in the oviductal epithelium of merino ewes during the estrous cycle (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 171 (1984), S. 441-456 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Isthmic and ampullary oviductal epithelia sampled from Merino ewes at days -1, 1, 3, and 10 of the estrous cycle (estrus = day 0) were studied by scanning and transmission electron microscopy after fixation by vascular perfusion. Secretory cells, ciliated cells, and lymphocytelike basal cells were observed in both isthmic and ampullary epithelium at all stages of the estrous cycle studied and their ultrastructural features were analyzed. Synthesis of lamellated secretory granules occurred in the ampullary secretory cells during the follicular and early luteal phases, and their contents were released by exocytosis into the oviductal lumen during the luteal phase. Granule release was associated with nucleated apical protrusion of these cells into the oviductal lumen. No such secretory activity was displayed by isthmic secretory cells even though a few cells contained nonlamellated granules. Apocrine release of apical vesicles and accompanying cytoplasmic material from apical protrusions of ciliated cells occurred in the isthmus around estrus but not in the ampulla. This unexpected feature has not previously been reported in any other mammal. Dendritic basal cells were distinguished in the lower part of the epithelium by their heterochromatic nuclei, electron-lucent cytoplasm, and lack of attachment zones. No migration of basal cells was observed, and their ultrastructural features were similar in the ampulla and isthmus and at all stages of the estrous cycle examined. The function of these lymphocytelike cells in the epithelium is uncertain, but the presence of phagocytic bodies and lysosomes in 20% of them may indicate a phagocytic role.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001710408
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    Paper (German National Licenses)
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