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  • Artikel  (15)
  • Chemistry  (9)
  • Ant-plant interactions  (2)
  • Czech Republic  (2)
  • Atlantis II Deep brines
  • CR: G1.3
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 57 (1990), S. 473-479 
    ISSN: 0945-3245
    Schlagwort(e): AMS(MOS): 65F10 ; CR: G1.3
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Summary The Meijerink, van der Vorst type incomplete decomposition uses a position set, where the factors must be zero, but their product may differ from the original matrix. The smaller this position set is, the more the product of incomplete factors resembles the original matrix. The aim of this paper is to discuss this type of monotonity. It is shown using the Perron Frobenius theory of nonnegative matrices, that the spectral radius of the iteration matrix is a monotone function of the position set. On the other hand no matrix norm of the iteration matrix depends monotonically on the position set. Comparison is made with the modified incomplete factorization technique.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    International journal of earth sciences 82 (1993), S. 42-50 
    ISSN: 1437-3262
    Schlagwort(e): Zircon dating ; Sphene dating ; Bohemian Massif ; Orthogneisses ; Czech Republic
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie
    Notizen: Abstract Zircon ages are reported for three Moldanubian amphibolite grade orthogneisses from the southern Bohemian Massif obtained by conventional U/Pb analyses. For two of these orthogneisses, conventional U/Pb data are supported by ion microprobe single zircon ages or single grain evaporation data. The amphibolite grade orthogneisses, occurring in three small tectonic lenses within the Varied Group close to the South Bohemian Main Thrust, are of tonalitic, granodioritic or quartz dioritic composition. Conventional bulk size fraction and ion microprobe analyses of nearly euhedral zircons from a metatonalite, erroneously interpreted as a metagreywacke in a previous study, yielded an upper Concordia intercept age of 2048 ± 12 Ma. The well preserved euhedral grain shapes of the zircons suggest crystallization from a magmatic phase, and the upper Concordia intercept age is now interpreted as reflecting a magmatic event at that time. The age of this rock is compatible with the conventional zircon data and the (207Pb/206Pb)* single grain evaporation result from two further orthogneisses providing intrusion ages of 2 060 ± 12, 2 104 ± 1 and 2 061 ± 6 Ma, respectively. For one sample a concordant U/Pb age for sphene of 355 ± 2 Ma defines the age of amphibolite facies metamorphism. The upper Concordia intercept ages of three orthogneisses constitute the first direct evidence for the presence of early Proterozoic crust under the supracrustal cover in the southern part of the Bohemian Massif.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    ISSN: 1432-1939
    Schlagwort(e): Ant-plant interactions ; Herbivory Macaranga ; Mutualism ; Myrmecophytes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The pioneer tree Macaranga in SE Asia has developed manyfold associations with ants. The genus comprises all stages of interaction with ants, from facultative relationships to obligate myrmecophytes. Only myrmecophytic Macaranga offer nesting space for ants and are associated with a specific ant partner. The nonmyrmecophytic species are visited by a variety of different ant species which are attracted by extrafloral nectaries (EFN) and food bodies. Transitional Macaranga species like M. hosei are colonized later in their development due to their stem structure. Before the colonization by their specific Crematogaster partner the young plants are visited by different ant species attracted by EFN. These nectaries are reduced and food body production starts as soon as colonization becomes possible. We demonstrated earlier that obligate ant partners can protect their Macaranga plants against herbivore damage and vine cover. In this study we focused on nonspecific interactions and studied M. tanarius and M. hosei, representing a non-myrmecophyte and a transitional species respectively. In ant exclusion experiments both M. tanarius and M. hosei suffered significantly higher mean leaf damage than controls, 37% versus 6% in M. hosei, 16% versus 7% in M. tanarius. M. tanarius offers both EFN and food bodies so that tests for different effects of these two food rewards could be conducted. Plants with food bodies removed but with EFN remaining had the lowest mean increase of herbivore damage of all experimental groups. Main herbivores on M. hosei were mites and caterpillars. Many M. tanarius plants were infested by a shootborer. Both Macaranga species were visited by various ant species, Crematogaster spp. being the most abundant. We found no evidence for any specific relationships. The results of this study strongly support the hypothesis that non-specific, facultative associations with ants can be advantageous for Macaranga plants. Food bodies appear to have lower attractive value for opportunistic ants than EFN and may require a specific dietary adaptation. This is also indicated by the fact that food body production in the transitional M. hosei does not start before stem structure allows a colonization by the obligate Crematogaster species. M. hosei thus benefits from facultative association with a variety of ants until it produces its first domatia and can be colonized by its obligate mutualist.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    ISSN: 1432-072X
    Schlagwort(e): Flexistipes ; Eubacteria ; Atlantis II Deep brines ; Red Sea
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Four isolates of a gram-negative flexible bacterium have been obtained from brine water samples of the Atlantis II Deep of the Red Sea at a depth of 2000 m. One isolate (MAS 10) was studied in detail. Cells are nonmotile, flexible rods, measuring about 0.3 μm in width and 5 to 50 μm in length. The new organisms are heterotrophs growing anaerobically on yeast extract, meat extract, peptone, tryptone, and, less efficiently, on acetate and casamino acids. Growth occurs between 30% and 53°C at pH 6 to 8 in the presence of at least 3% NaCl. The shortest doubling time is 8.5 h under optimal growth conditions. Cells are sensitive to the antibiotics penicillin, ampicillin, vancomycin, and streptomycin, but resistant to tetracyclin and rifamipicin. The GC-content of the DNA is 39 mol%. Based on their 16S rRNA the new isolates group with the general cluster of eubacterial phyla. Since they show no specific relationship to any of them, a new genus is described, which is named Flexistipes, the flexible stick. Type species is Flexistipes sinusarabici strain MAS 10 (DSM 4947).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 180 (1992), S. 53-64 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Euphorbiaceae ; Macaranga ; Ant-plant interactions ; domatia ; evolution ; myrmecophytism ; Flora of Malaysia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The paleotropical tree genusMacaranga (Euphorbiaceae) comprises all stages of interaction with ants, from facultative associations to obligate myrmecophytes. In SE.-Asia food availability does not seem to be the limiting factor for the development of a close relationship since all species provide food for ants in form of extrafloral nectar and/or food bodies. Only myrmecophyticMacaranga species offer nesting space for ants (domatia) inside internodes which become hollow due to degeneration of the pith. Non-myrmecophytic species have a solid stem with a compact and wet pith and many resin ducts. The stem interior of some transitional species remains solid, but the soft pith can be excavated. The role of different ant-attracting attributes for the development of obligate ant-plant interactions is discussed. In the genusMacaranga, the provision of nesting space seems to be the most important factor for the evolution of obligate myrmecophytism.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    ISSN: 0886-9383
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    ISSN: 0016-7835
    Schlagwort(e): Key words HP granulites ; Zircon dating ; Rutile dating ; Lower Carboniferous ; N Bohemia ; Czech Republic
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie
    Notizen: Abstract  U–Pb zircon and rutile multigrain ages and 207Pb/206Pb zircon evaporation ages are reported from high-pressure felsic and metapelitic granulites from northern Bohemia, Czech Republic. The granulites, in contrast to those from other occurrences in the Bohemian Massif, do not show evidence of successive HT/MP-LP overprints. Multigrain size fractions of nearly spherical, multifaceted, metamorphic zircons from three samples are slightly discordant and yield a U–Pb Concordia intercept age of 348±10 Ma, whereas single zircon evaporation of two samples resulted in 207Pb/206Pb ages of 339±1.5 and 339±1.4 Ma, respectively. A rutile fraction from one sample has a U–Pb Concordia intercept age of 346±14 Ma. All ages are identical, within error, and a mean age of 342±5 Ma was adopted to reflect the peak of HP metamorphism. Because rutile has a lower closing temperature for the U–Pb isotopic system than zircon, the results and the P–T data imply rapid uplift and cooling after peak metamorphism. The above age is identical to ages for high-grade metamorphism reported from the southern Bohemian Massif and the Granulite Massif in Saxony. It can be speculated that all these granulites were part of the same lower crustal unit in early Carboniferous, being separated later due to crustal stacking and subsequent late Variscan orogenic collapse.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 335 (1993), S. 128-134 
    ISSN: 0941-1216
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Chlorination of 1-substituted 3-formyl-4-hydroxy-2-quinolones (1a, b) with phosphorylchloride leads to 4-chloro-3-dichloromethylquinolones (2), which can be hydrolyzed to 4-chloro-3-formyl-quinolones (4). From the anilinomethylene quinolinediones (3), at low temperatures the formylquinolones 4 can be obtained directly, whereas at high temperatures cleavage of the tautomeric azomethine moiety followed by subsequent ring closure to the naphthyridines (7) takes place. With 1-unsubstituted 3-formyl-4-hydroxy-2-quinolones (1d) either the 3-dichloromethylquinolone (2d) or the 2,4-dichloro-3-dichloro-methylquinoline (10) is obtained depending on the reaction conditions. Similar results are obtained with the 1-unsubstituted anilinomethylene compounds (3). Attempts to obtain the 3-formyl-2,4-dichloroquinoline (11) were unsuccessful because in all experiments the 2-chloro-group was converted to an oxygen function.
    Zusätzliches Material: 8 Tab.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 154 (1972), S. 81-88 
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: The reaction course of glycidyl benzoate with aliphatic, aromatic, heterocyclic primary and secondary amines and imidazol in the presence of isobutanol has been studied. The reaction of glycidyl compounds with amines has a termolecular mechanism. In the presence of an alcohol the reaction is pseudobimolecular. The basic dissociation constant of the amine can be applied for the determination of the approximate velocity constant for the reaction of glycidyl benzoate with amines. A greater deviation from the dependence between the dissociation constant of an amine and the velocity constant of the reaction was found with benzylamine. The activation energy of the reaction of glycidyl benzoate with amines has been determined.
    Notizen: Die Umsetzung von Benzoesäureglycidylester mit aliphatischen, aromatischen und heterocyclischen primären und sekundären Aminen in Gegenwart von Isobutylalkohol wurde studiert. Die Reaktion der Glycidylverbindungen mit Aminen verläuft nach einem termolekularen Mechanismus. In Alkohol als Lösungsmittel wird ein pseudobimolekularer Reaktionsverlauf ermittelt. Die basische Dissoziationskonstante des Amins kann zur Bestimmung der approximativen Geschwindigkeitskonstante der Benzoesäureglycidylester-Amin-Reaktion verwendet werden. Eine größere Abweichung von der Abhängigkeit zwischen der Dissoziationskonstante des Amins und der Geschwindigkeitskonstante der Umsetzung wurde beim Benzylamin gefunden. Die Aktivierungsenergie für die Reaktion von Benzoesäureglycidylester mit Aminen wurde bestimmt.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 20 (1971), S. 103-110 
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: The benzyl dimethylamine catalyzed copolyaddition of glycidyl benzoate with hexahydrophthalic anhydride has been investigated. The orders of reaction towards hexahydrophthalic anhydride, glycidyl benzoate and benzyl dimethylamine have been determined. The activation energy of the reaction has been determined from the reaction rate constant/temperature dependence. It has been found that the reaction mechanism is strongly influenced by the catalytic amine concentration as well as by the fact that practically all amine is complexed. A reaction mechanism has been suggested.
    Notizen: Die mit Benzyldimethylamin katalysierte Copolyaddition von Benzoesäureglycidylester mit Hexahydrophthalsäureanhydrid wurde untersucht. Dazu wurde die Reaktionsordnung für Hexahydrophthalsäureanhydrid, Benzoesäureglycideylester und Benzyldimethylamin bestimmt. Aus der Abhängigkeit der Reaktionsgeschwindigkeitskonstante von der Temperatur wurde die Aktivierungsenergie der Readtion ermittelt. Der Reaktionsmechanismus wird durch die katalytische Konzentration des Amins und durch die Tatsache, daß praktisch das gesamte Amin in Komplexe eingebaut wird, stark beeinflußt. Ein Reaktionsmechanisums wurde entworfen.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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