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  • 1
    Electronic Resource
    Electronic Resource
    Predation on zooplankton by the benthic anthozoans Alcyonium siderium (Alcyonacea) and Metridium senile (Actiniaria) in the New England subtidal (1984)
    Springer
    Marine biology 81 (1984), S. 255-271 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Alcyonacean octocoral Alcyonium siderium Verrill and the sea anemone Metridium senile (L.), the only common perennial zooplanktivores on shallow (≦16-m depth) subtidal rock walls in much of northern New England, USA, are of similar heights and overlap in their habitat and microhabit distributions. The coelenteron contents of both species were sampled at four-hour intervals over a diel cycle and were compared to zooplankton available in the water at 1 to 5 cm from the rock wall, the height at which the cnidarians held their feeding tentacles. Prey in coelenterons of A. siderium were significantly smaller (means of 256 to 345 μm), and those in coelenterons of M. senile were equal to or slightly greater in length (means of 415 to 1006 μm) than the available zooplankton. The diets of A. siderium and M. senile differed significantly from each other and from the available zooplankton. A. siderium showed strong positive electivites for ascidian larvae and for foraminiferans, and strongly negative electivities for most crustaceans. M. senile had strong positive electivities for barnacle cyprids, ascidian larvae, and gammarid amphipods, and strong negative electivities for invertebrate eggs, foraminiferans, calanoid and harpacticoid copepods, and ostracods. Electivities may reflect tentacle avoidance or escape by motile prey as well as predator preference. Substratum-associated organisms (e.g. demersal crustaceans, larvae of benthic invertebrates) were the most common items in the diets of both species, suggesting a tight benthic food web, similar to the situation for coral reef anthrozoans which rely on reef-generated zooplankton. A. siderium ate large numbers of ascidian larvae which, as benthic adults, compete for space with A. siderium and can overgrow small colonies. Predation on the larvae of a competing species may alleviate competition by decreasing the competitor's recruitment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00393220
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  • 2
    Electronic Resource
    Electronic Resource
    Difference properties for Banach-valued functions (1969)
    Springer
    Mathematische Annalen 181 (1969), S. 288-296 
    Details
    ISSN: 1432-1807
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01350668
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  • 3
    Electronic Resource
    Electronic Resource
    Pricing of non-redundant derivatives in a complete market (1998)
    Springer
    Review of derivatives research 2 (1998), S. 287-314 
    Details
    ISSN: 1573-7144
    Keywords: incomplete markets ; equilibrium ; derivatives ; pricing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Economics
    Notes: Abstract We consider a complete financial market with primitive assets and derivatives on these primitive assets. Nevertheless, the derivative assets are non-redundant in the market, in the sense that the market is complete,only with their existence. In such a framework, we derive an equilibrium restriction on the admissible prices of derivative assets. The equilibrium condition imposes a well-ordering principle restricting the set of probability measures that qualify as candidate equivalent martingale measures. This restriction is preference free and applies whenever the utility functions belong to the general class of Von-Neumann Morgenstern functions. We provide numerical examples that show the applicability of the restriction for the computation of option prices.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01574150
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  • 4
    Electronic Resource
    Electronic Resource
    Basische Tetrahydro-dibenzofuran-Derivate mit einem Abstand von drei C-Atomen zwischen dem Stickstoff und dem quartären C-Atom (1978)
    Springer
    Monatshefte für Chemie 109 (1978), S. 1099-1113 
    Details
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Pummerer's ketone (1) is a “pharmacophoric synthon”, which can be used for a great number of synthetic variations. We have investigated the insertion of basic groups into C-1, C-2 and C-3. TheClaisen rearrangement of the allylic alcohols2 a and2 b leads to3 a and3 b, the reduction of which produces4 a and4 b. TheMannich reaction of1 unexpectedly gives the 2-aminoalkylcompounds7 c-j and the synthesis of the derivatives2e-j was performed by aminolysis of the 3-chloro-compound2 d.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00913013
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  • 5
    Electronic Resource
    Electronic Resource
    Studien über Moorfulturen (1894)
    Springer
    European journal of forest research 16 (1894), S. 505-526 
    Details
    ISSN: 1612-4677
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01841854
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  • 6
    Electronic Resource
    Electronic Resource
    Studien über Moorfulturen (1894)
    Springer
    European journal of forest research 16 (1894), S. 452-470 
    Details
    ISSN: 1612-4677
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01845453
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  • 7
    Electronic Resource
    Electronic Resource
    Competitive ability of the antagonists Ulocladium atrum and Gliocladium roseum at temperatures favourable for Botrytis spp. development (1999)
    Springer
    BioControl 44 (1999), S. 329-346 
    Details
    ISSN: 1573-8248
    Keywords: biological control ; Botrytis aclada ; Botrytis cinerea ; cyclamen ; ecological adaptation ; hydrangea ; lily ; onion ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Ulocladium atrum and Gliocladium roseum are fungal antagonists capable of suppressing sporulation of Botrytis spp. on dead plant parts. The effect of temperature (3 to 36 °C) on antagonist conidial germination and mycelial growth was assessed on agar. In addition conidial germination of U. atrum was measured on dead lily leaves. The optimum temperature of both antagonists for both conidial germination and mycelial growth was between 27 and 30 °C. U. atrum was less affected by lower temperatures than G. roseum. At optimum temperature, 50% of conidia of U. atrum and G. roseum germinated within 2.6 and 10.0 hrs, respectively. At low sub-optimal temperatures (6 °C), 50% of conidia germinated within 18 and 96 hours, respectively. In bioassays on dead onion leaves, U. atrum suppressed sporulation of B. cinerea and B. aclada at all temperatures tested (6 to 24 °C) by more than 85%. On dead cyclamen leaves, G. roseum was more efficient than U. atrum at 21 and 24 °C but, in contrast to U. atrum, showed no antagonistic activity at temperatures below 21 °C. On dead hydrangea leaves, U. atrum significantly reduced sporulation of B. cinerea at temperatures as low as 3 and 1 °C. Under Dutch growing conditions, the mean air temperature during leaf wetness periods in onion and lily fields was 15 °C with temperatures only occasionally above 20 °C. In greenhouse crops of cyclamen, the mean temperature during high humidity periods was 17 °C. It is therefore concluded that U. atrum is better adapted than G. roseum to temperatures which occur in the field, in greenhouse crops such as cyclamen, or during cold storage of plant stocks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009907311624
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  • 8
    Electronic Resource
    Electronic Resource
    Flow, flapping, and photosynthesis ofNereocystis leutkeana: a functional comparison of undulate and flat blade morphologies (1988)
    Springer
    Marine biology 99 (1988), S. 435-444 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A number of species of macroalagae possess a flat, strap-like blade morphology in habitats exposed to rapidly-moving water whereas those at protected sites have a wider, undulate blade shape. We have explored the functional consequences of flat, narrow vs. wide, undulate blade morphologies in the giant bull kelpNereocystis luetkeana. Our study focused on the behavior of blades in ambient water currents and the consequences of that behavior to breakage and to photosynthesis. In flowing water, the narrow, flat blades flap with lower amplitude and collapse together into a more streamlined bundle than do wide, undulate blades, and hence experience lower drag per blade area at a given flow velocity. If the algae at current-swept sites had ruffled blades, drag forces would sometimes be sufficient to break the stipes. However, flat blades in a streamlined bundle experience more self-shading than do undulate blades, which remain spread out in water currents. Thus, there is a morphological trade-off between reducing drag and reducing self-shading. Photosynthetic14C-HCO3 uptake rates decrease in slow flow when the boundary layer along the blade surface across which diffusion takes place is relatively thick. However, blade flapping, which stirs water near the blade surface, enhances carbon uptake rates in slow water currents for both the undulate and the flat morphologies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02112137
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  • 9
    Electronic Resource
    Electronic Resource
    Lipofuscin und Lysosomen im menschlichen Nebenhoden (1968)
    Springer
    Histochemistry and cell biology 16 (1968), S. 236-286 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Fluorescence microscopical and histochemical investigations were carried out on lipofuscin and lysosomes in the epididymal epithelium of adults. The results are as follows: 1. The epithelium of the ductuli efferentes contains fluorescent granules of which number and size increase with advancing age. Within the cells of one ductule number, size, and intracellular position of the granules are mainly the same but vary in the cells of different ductules of the same organ. — Very fine fluorescent granules appear with advancing age of the individuum especially in the supranuclear zone of the zylindrical cells of the epididymal duct. Bigger granules which also increase in number with advancing age exist in the supranuclear zone but especially in the nuclear zone. The granulation of the basal zone and the basal cells corresponds to the one found in the two other zones. “Signet-ring like” vacuolar shapes are only found in the epithelium of the epididymal duct. 2. In the epithelium of the ductuli efferentes and of the ductus epididymidis the existence of the following enzyme activities in granules was proved: acid phosphatase, organophosphate resistant esterase, ß-glucuronidase, and acid deoxyribonuclease. The activity of these lysosomal enzymes shows constant différencies in both parts of the organ. — In the epithelium of the ductuli efferentes the fluorescent and the enzyme-containing granules are mainly identical. In the supranuclear zone of the epithelium of the epididymal duct the enzymecontaining granules are more numerous in most cases than the fluorescent granules. The latter belong to the lysosomes, too. — Especially in the ductuli efferentes the enzyme activity of the fluorescent granules shows differencies and can be lower or obviously missing in part of the granules. 3. According to their different number, size, and intracellular position, the histochemical properties of the fluorescent granules are also different. The small ones show a positive reaction with Baker's acid haematein test, sudanophilia in paraffin sections, and a positive PAS-reaction. They are interpreted as being regular lysosomes owning properties of the socalled propigment. The big granules are characterized as lipofuscin granules by their inherent colour, sudanophilia, capability of reduction, basophilia, and acid fastness. Further qualities known from experimental investigations of pigment formation are being described and related to the formation of lipofuscin. It is possible to assume stages of development which lead from lysosomes with properties of the so-called propigment to the lipofuscin granules and further to cell inclusions without enzyme activity. According to the age it is possible to observe the stages of this development in different ductuli efferentes of the same organ. These stages show typical differencies in their positional relation to the nucleus. — In the zylindrical cells of the epididymal duct the lipofuscin granules lying in the nuclear zone arise from the lysosomes of the supranuclear zone. 4. The variable lysosome content of the individual ductuli efferentes points to a variable pinocytotic activity of the “vacuolar apparatus” of the epithelial cells. The corresponding differencies in the lipofuscin content of the various ductules have to be seen in relationship with this cell function. — For the lysosomes of the zylindrical cells of the epididymal duct it is possible to assume both participation in pinocytosis and relation to a possible secretoric activity of these cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307852
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  • 10
    Electronic Resource
    Electronic Resource
    Zur Entwicklung des Subcommissuralorgans der Ratte Morphologische und histochemische Untersuchungen (1973)
    Springer
    Histochemistry and cell biology 33 (1973), S. 349-368 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die Entwicklung des Subcommissuralorgans (SCO) der Ratte wurde morphologisch und histochemisch untersucht. Zwischen dem 15. und 16. Embryonaltag steigt mit Ausbildung der hochprismatischen Ependymzellen die Enzymaktivität des Energiestoff-wechsels (GAP-DH, LDH, SDH, CyO) deutlich an, wobei die anaerobe Glykolyse überwiegt. Die gleichzeitige Aktivitätszunahme der G6P-DH, NADPH2-Reduktase, Thiaminpyrophos-phatase und sauren Phosphatase führt zu dem für das Ependym der adulten Ratte charakteristischen Enzymmuster. Dieser bis zum 18. Tag anhaltende Anstieg wird mit der beginnenden sekretorischen Tätigkeit in Beziehung gebracht. Der Glykogengehalt nimmt ebenfalls allmählich zu. Nach der Geburt fällt die Enzymaktivität des Energiestoffwechsels allmählich ab. Der Glykogengehalt und die Zahl apikaler Protrusionen nehmen anfänglich noch zu, dann aber ebenfalls langsam ab. Es wird auf einen Rückgang der sekretorischen Aktivität geschlossen. An dem nur spärlich ausgebildeten Hypendym treten erst in der 3. Lebenswoche ähnliche Änderungen der Enzymaktivitäten und des Sekretgehalts auf. Mit dieser verzögerten Entwicklung des Hypendyms schließt die Differenzierung des SCO in der 4. Lebenswoche ab. Die Anlage eines besonderen Ependymbereichs, der okzipital an das SCO anschließt, wird beschrieben. Vor der Geburt weist er dem SCO vergleichbare morphologische und histochemische Eigenschaften auf, fehlt jedoch bei der erwachsenen Ratte. Die mögliche Bedeutung dieser Kückbildung wird diskutiert.
    Notes: Summary The development of the Subcommissural organ (SCO) of the rat has been investigated morphologically and histochemically. Between the 15th and 16th prenatal day elongated ependymal cells appear. The activities of enzymes of the energy metabolism (GAP-DH, LDH, SDH, CyO), particularly of the anaerobic glycolysis, increase. With the synchronous increase of activities of G6P-DH, NADPH2-reductase, thiamine pyrophosphatase and acid phosphatase, an enzyme pattern appears which is characteristic for the ependyma of the adult rat. This increase which is observed to the 18th day may correspond to the onset of the secretory activity. The content of glycogen increases gradually. After birth the enzyme activities of the energy metabolism decrease gradually. After an initial increase, the glycogen content and the amount of apical protrusions decrease, too. The amount of secretory material increases till the 10th day, and remains unchanged thereafter. This may reflect a decrease in secretory function. The hypendyma is poorly developed. Similar changes in enzyme activities and secretory content appear in the 3rd postnatal week. In the 4th week the differentiation of the SCO is completed. The anlage of a specialized ependyma adjoning the SCO caudally is described. Prenatally it has some of the morphological and histochemical characteristics of the SCO. It has not been observed in the adult rat. The possible significance of this involution is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00306264
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