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  • 1
    Electronic Resource
    Electronic Resource
    Taxonomic status ofFormica subnitens Creighton and F. integroides Emery, with a description of the sexuals ofF. subnitens (Hymenoptera: Formicidæ) (1957)
    Springer
    Insectes sociaux 4 (1957), S. 253-257 
    Details
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Field and laboratory data onFormica subnitens Creighton andF. integroides, Emery confirm Cole's assumption that these entities are species. The female and male ofF. subnitens are described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02222157
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  • 2
    Electronic Resource
    Electronic Resource
    Juvenile hormone titre and regulation in the cockroachDiploptera punctata (1985)
    Springer
    Cellular and molecular life sciences 41 (1985), S. 1028-1034 
    Details
    ISSN: 1420-9071
    Keywords: Cockroach ; Diploptera punctata ; juvenile hormone titre ; juvenile hormone half-life ; juvenile hormone release rate ; gonotrophic cycle ; allatectomy ; nonhemolymph juvenile hormone pool
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Titres of juvenile hormone (JH) have been determined in both hemolymph and whole body extracts of femaleDiploptera punctata during the first gonotrophic cycle using a method employing gas chromatography/mass spectrometry for qualitative and quantitative analysis. JH III is the sole JH found in both adult and last instarD. punctata. Maximum values of ∼ 1500 ng/ml (∼6μM) were observed at the middle of the gonotrophic cycle, when basal oocyte growth rate was greatest. Changes in rates of JH release in vitro by corpora allata paralleled closely the changes in JH titre, suggesting that biosynthesis is a major regulator of titre. JH levels per animal were calculated from observed JH titres, and at certain time points in the gonotrophic cycle JH levels obtained from analysis of whole bodies were significantly greater than those predicted from hemolymph titres. These results suggest the existence of a nonhemolymph JH pool inD. punctata. Decay in JH titre after allatectomy of 5 day females has also been studied. Following a rapid initial decline, the rate of decay slowed appreciably 4 h post-operation. Thus, use of a first-order rate constant to estimate half-life of JH significantly underestimated the longevity of the hormone. The apparent persistence of JH following allatectomy may be due to the existence of a nonhemolymph JH pool.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01952127
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  • 3
    Electronic Resource
    Electronic Resource
    A scanning electron microscope study of the mandibular morphology of boreal copepods (1975)
    Springer
    Marine biology 30 (1975), S. 175-182 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Morphological details of the mandibular blades of 11 species of copepods were examined with scanning electron microscopy. The micrographs improved our understanding of the complex toothed edge of the mandibular blade, which in turn aids in identification of the copepod prey of chaetognaths by gut-content analysis. Beklemishev's discovery of siliceous tooth crowns in calanoid copepods was confirmed for most of the species examined. Long, sharp projections on the crowns of herbivorous species, and the deep grooves into which they fit on the teeth of the opposite mandible, suggest a cracking rather than a grinding function for these teeth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00391591
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  • 4
    Electronic Resource
    Electronic Resource
    Morphogenesis of opal teeth in calanoid copepods (1990)
    Springer
    Marine biology 106 (1990), S. 91-101 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Opal teeth of calanoid copepods develop early in the premolt phase of the molt cycle. They form in the apolysis space beneath the old tooth row on the mandibular gnathobase. We examined stages of tooth formation inNeocalanus spp. andCalanus pacificus. Apolysis occurs early in the distal gnathobase, then several epidermal cell types participate sequentially in formation of new teeth. Fibrous molds in the shapes of the new teeth are extruded onto the epidermal surface, then additional materials, probably proteinaceous, are secreted into them. Tooth molds next are linked to a gland in the proximal part of the gnathobase by ducts of an unusual type, “lamellar-walled ducts.” Silicification follows, apparently using highly osmiophilic material supplied by the proximal gland. Opal is laid down at the outer periphery of the mold then thickens toward the attachment of the mold to newly formed chitin at its base. During apolysis the epidermal cells move proximally without breaking ducts that connect small dermal glands with pores in the sides of the opal teeth. The molds for the new teeth form surrounding these ducts, and new pores result. The glands are like the ciliary exocrine glands seen in other Crustacea, with the duct deriving from fusion of the axonemes of a cilium. Presumably the glands secrete a substance into food newly broken by the teeth. This could be a toxin or a digestive enzyme.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02114678
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  • 5
    Electronic Resource
    Electronic Resource
    Ingestion-independent rates of ammonium excretion by the copepod Calanus pacificus (1984)
    Springer
    Marine biology 78 (1984), S. 265-270 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The relationship between food ingested and NH + 4 excretion rate was investigated for female Calanus pacificus collected in August, 1982, from the San Juan Archipelago, Washington State, USA. The copepods were preconditioned to 6 densities of the diatom Thalassiosira weissflogii (0 to 104 cells ml−1) for 30 h before the experiment. The experiment was conducted with nutrients added in excess to maintain equal rates of NH + 4 uptake by the diatoms at all densities. Although ingestion rates of C. pacificus varied from 0 to over 20% of body N d−1 at the different food levels, excretion was a constant 6.6 nM NH + 4 copepod−1 h−1 or about 10% of body N d−1. This ingestion-excretion relationship, which is consistent with previous respiration and fecundity studies, suggests that the ecological dominance of C. pacificus only under conditions of high food abundance may be due to a dramatic increase in its growth efficiency as ingestion increases above the level supporting a constant metabolic rate. The maintenance of a constant level of metabolism during relatively short periods of low food abundance may be advantageous if it allows the copepod to exploit more effectively short-term variability in its food resulting from environmental heterogeneity or vertical migration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00393012
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  • 6
    Electronic Resource
    Electronic Resource
    Seasonal cycles of abundance in zooplankton populations of Yaquina Bay, Oregon (1973)
    Springer
    Marine biology 21 (1973), S. 277-288 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Descriptions of the seasonal cycles of abundance of the dominant zooplankters of Yaquina Bay, Oregon, USA, are derived from a 7 year series of net samples taken at two downstream stations. The summer dominants are forms distributed to the north, along the American coast. Winter dominants have sonthern affinities. This cycle is associated with the annual cycle of coastal surface currents: from north to south in summar, reversed in winter. There are no persistent trends in the abundance data from year-to-year.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00381084
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  • 7
    Electronic Resource
    Electronic Resource
    Reproduction of meso- and bathypelagic chaetognaths in the genus Eukrohnia (1982)
    Springer
    Marine biology 71 (1982), S. 193-196 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Reproduction of meso- and bathypelagic chaetognaths, a major group of zooplankton and hermaphroditic animals, became clear after the microscopic examination of samples collected from the Pacific Subarctic Water. Species of the genus Eukrohnia carry their developing eggs in two marsupial sacs, one on each side, and the young are retained in these marsupia for at least some period after hatching. This is in line with a general trend for low fecundity, as care of the young increases. Almost all individuals are protandric, the testes maturing sooner than ovaries. These facts suggest that the reproduction of these species depends upon cross-fertilization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00394629
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  • 8
    Electronic Resource
    Electronic Resource
    Vertical habitat-partitioning by copepodites and adults of subtropical oceanic copepods (1987)
    Springer
    Marine biology 94 (1987), S. 561-577 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Vertical distributions of the abundant larger copepods, both adults and late copepodites, were observed day and night in the upper 500 m of the North Pacific central gyre in early November, 1971. Densities of the copepodites usually equalled or exceeded those of the adults. Copepod species with maximum densities at or above 100 m (Calanus spp., Nannocalanus minor f. major, Undinula darwini, and Euchaeta rimana) usually had no ontogenetic or diel migration. Neocalanus spp. and Haloptilus longicornis exhibited ontogenetic but not diel migrations. Nannocalanus minor f. minor, Aetideus acutus, Euchaeta media, Scolecithrix spp. and Pleuromamma spp., had both ontogenetic and diel migrations. Adults and copepodites of E. media and Pleuromamma spp. usually had their night modes at the same depth, but the daytime modes were at progressively deeper depths for progressively older stages. Daytime modes for adults and copepodites of A. acutus and Scolecithrix bradyi were at the same depth, but the nighttime modes were at shallower depths for progressively older stages. Night modes of all these migrators were usually in the mixed layer (75 m), where primary production rates were maximal. Congeners usually had similar migratory behavior, but competition probably has been a significant determinant of vertical distribution, since congeners, particularly “sibling species”, consistently had different depths of maximum occurrence during both day and night.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00431403
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  • 9
    Electronic Resource
    Electronic Resource
    Experimental results for the L3 phase in a zwitterionic surfactant system and their implications regarding structures (1990)
    Springer
    Colloid & polymer science 268 (1990), S. 1066-1072 
    Details
    ISSN: 1435-1536
    Keywords: Alkyldimethylamine oxide ; surfactantsphasediagrams ; L 3 -phase ; plate likemicelles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Conditions for existence of the L3 phase have been determined for a system containing water, n-hexanol, and the zwitterionic surfactant n-tetradecyldimethylamineoxide. Electric birefringence, light-scattering, rheology, and electrical-conductivity experiments were performed on this phase. Results are consistent with the existence of platelike micelles, whose diameter changes with surfactant concentration in such a way that it remains comparable to mean plate spacing. This behavior can be understood in terms of a previous L3 phase theory containing randomly oriented plates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01410596
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  • 10
    Electronic Resource
    Electronic Resource
    Konformative Einflüsse bei der Dehydrierung von Phenol-Mannichbasen (1974)
    Springer
    Monatshefte für Chemie 105 (1974), S. 1151-1163 
    Details
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The preparation of some Mannich bases from phenols, benzaldehyde and secondary amines is described and their behaviour to the mercuric-EDTA dehydrogenation is examined. The pyrrolidine derivative yields a lactam, the formation of which is explained by special conformative circumstances.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00909848
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