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  • 1
    Electronic Resource
    Electronic Resource
    Scheduling activities among conflicting facilities to minimize conflict cost (1974)
    Springer
    Mathematical programming 6 (1974), S. 224-228 
    Details
    ISSN: 1436-4646
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01580238
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  • 2
    Electronic Resource
    Electronic Resource
    Über 3,4-Bis-(p-hydroxyphenyl)-hexandiole-(2,5) und ihre 2,5-Dimethylhomologen (1964)
    Springer
    Monatshefte für Chemie 95 (1964), S. 1713-1720 
    Details
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract Of the two (meso andracemic) 3,4-di(p-methoxyphenyl)-hexanediones-(2,5) described in the previous communication, themeso compound has been converted by reduction into two (of the three possible) corresponding secondary diols. Demethylation of the higher melting isomer yielded 3,4-di(p-hydroxyphenyl)-hexanediol-(2,5) (“dihydroxyhexestrol”). Attempts to obtain the corresponding hexestrol by reduction and hence to determine its configuration remained unsuccessful. The preparation of homologous tertiary diols by reaction of the two hexanedione derivatives (meso andracemic) with CH3MgX has been investigated more closely; on ether cleavage the two di-homologous dihydroxyhexestrols were formed. The Grignard reaction was also carried out on themeso hexanedione without subsequent demethylation.
    Notes: Zusammenfassung Von den in der vorigen Mitteilung beschriebenen 3,4-Bis-(p-methoxyphenylhexandionen-(2,5) [meso undracem.] wurde diemeso-Verbindung durch Reduktion in zwei (der drei möglichen) entsprechende sekundäre Diole übergeführt und das höherschmelzende Diol durch Entmethylierung in ein 3,4-Bis-(p-hydroxyphenyl)-hexandiol-(2,5) (“Dihydroxyhexoestrol) umgewandelt. Versuche, durch Reduktion eine Überführung in ein Hexoestrol zu erreichen und die sterische Anordnung festzulegen, schlugen sämtlich fehl. Eingehender wurde die Gewinnung homologer tertiärer Diole durch Umsetzung der beiden Hexandionderivate (meso undracem.) mit CH3MgX bearbeitet, wobei unter Ätherspaltung die beiden Bis-homologen-dihydroxy-hexoestrole resultierten. Ammesoiden Hexandionderivat wurde auch die Grignardreaktion allein (ohne Entmethylierung) durchgeführt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00901731
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  • 3
    Electronic Resource
    Electronic Resource
    The influence of shock-waves on UV-emission-lines (1975)
    Springer
    Solar physics 45 (1975), S. 93-103 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract If shock-waves are running outwards through the solar atmosphere, the variations of the intensity of optically thin UV-lines should reflect the variations in temperature and pressure of the shocks. In addition, the high fluid velocity produces Doppler shifts in the local line profiles. Assuming vertically propagating shockwaves with a period of 200 s, a procedure is specified for calculating the time-dependent line profile for a radial line of sight. The width of the shock pulse which characterizes the shape of the shock, is treated as a free parameter. Because the processes of ionization and recombination are out of equilibrium, the relative ion densities are obtained by solving the continuity equations. Results are presented for the O vi-resonance-line 1032 Å.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00152220
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  • 4
    Electronic Resource
    Electronic Resource
    Dose–Tissue Relationships for Dieldrin in Nestling Black-Billed Magpies (2000)
    Springer
    Bulletin of environmental contamination and toxicology 65 (2000), S. 427-434 
    Details
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s0012800025
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  • 5
    Electronic Resource
    Electronic Resource
    Heterozygosity, growth, and survival of the hard clam,Mercenaria mercenaria, in seagrass vs sandflat habitats (1991)
    Springer
    Marine biology 111 (1991), S. 335-342 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Populations of the hard clam,Mercenaria mercenaria L., sampled from dissimilar, adjacent habitats (October and November 1987), were used to assess environmental effects on associations among multi-locus heterozygosity, growth, and survival. Individuals were collected from three widely separated localities along the east coast of North America with each consisting of a seagrass bed and an adjacent, unvegetated sandflat. Demographic differences between adjacent populations were attributed to habitat type. Samples from intertidal sandflats at two of the localities were dominated by younger individuals than those from seagrass beds. Differential growth between adjacent populations was detected at only one locality wherein seagrass individuals grew faster than those from the sandflat. Allelic frequencies revealed adjacent populations that were genetically homogeneous. Nearly all of the genetic variance (98%) was within populations, yet a small (1.7%), but significant, portion occurred between localities. Observed and expected heterozygosities revealed a deficiency of heterozygotes in all six samples. Inbreeding and small-scale population subdivision were discounted as causative factors because deficiencies were heterogeneous across loci. Multi-locus heterozygosity was not correlated with growth rate in samples from any locality. Using a consensus test, multilocus heterozygosity was positively associated with ageclass in sandflat, but not seagrass, samples. We suggest that heterozygosity-fitness trait associations in marine bivalves are more likely to occur in populations inhabiting more stressful, fluctuating environments
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01319404
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  • 6
    Electronic Resource
    Electronic Resource
    Hatching and viability of copepod eggs at two stages of embryological development: anoxic/hypoxic effect (1994)
    Springer
    Marine biology 119 (1994), S. 199-204 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of low oxygen concentrations on the hatching and viability of copepod eggs at two stages of embryological development were investigated. Fully developed eggs from Acartia tonsa (Dana) and Labidocera aestiva (Wheeler) collected between July and September 1991 at Turkey Point, Florida, USA, hatched at lower oxygen concentrations than newly spawned eggs given the same incubation periods. Since many of the newly spawned eggs subsequently hatched when exposed to normoxic conditions, it is likely that the exposure to low oxygen delayed embryonic development. At oxygen concentrations where no initial hatching occurred, the subsequent hatching success of fully developed eggs of A. tonsa was higher than that of newly spawned eggs, indicating that newly spawned eggs were more sensitive to low oxygen concentrations. No such difference was observed for the eggs of L. aestiva.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349557
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  • 7
    Electronic Resource
    Electronic Resource
    Gene flow among vestimentiferan tube worm (Riftia pachyptila) populations from hydrothermal vents of the eastern Pacific (1994)
    Springer
    Marine biology 120 (1994), S. 33-39 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Allozyme data are presented for six discrete populations of the giant hydrothermal vent tube worm Riftia pachyptila Jones, 1981 collected throughout the species' known range along mid-ocean spreading ridges of the eastern Pacific Ocean. Contrary to an earlier report, levels of genetic variation are relatively high in this species. Estimates of gene flow based on F-statistics revealed that dispersal throughout the surveyed region is sufficiently high to counter random processes that would lead to losses of genetic diversity and significant population differentiation. R. pachyptila, like other species of tube worms, displays considerable morphologic variation among populations, but this diversity is not reflected in allozyme variation. Vestimentifera, in general, appear to show extensive phenotypic plasticity. In the light of the available genetic data, caution is warranted when making inferences about the taxonomic status of collections based on morphological variation alone. A general decrease in estimated rates of gene flow between geographically more distant populations supports the hypothesis that dispersal in this species follows a stepping-stone model, with exchange between neighboring populations in great excess of long-distance dispersal. High levels of gene flow have been recorded in a variety of vent fauna and may be a prerequisite for success of species found in the ephemeral habitats associated with regions of sea-floor hydrothermal activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00381939
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  • 8
    Electronic Resource
    Electronic Resource
    Effects of anoxia on the viability of subitaneous eggs of planktonic copepods (1994)
    Springer
    Marine biology 121 (1994), S. 83-87 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of anoxia on the viability (as evidenced by hatching) of newly spawned and fully developed subitaneous eggs of three species of copepods, Acartia tonsa (Dana), Centropages hamatus (Lilljeborg), and Labidocera aestiva (Wheeler) was determined for eggs produced in the laboratory by adults collected from inshore waters of the northeastern Gulf of Mexico between January and August 1992. Hatching success decreased to 50% or less when eggs were exposed to oxygen concentrations 〈0.06 mll-1 for more than 12 d, except for newly spawned eggs of L. aestiva, which still showed 50% survival after 32 d of exposure to anoxia. For all three species, newly spawned eggs survived exposure to anoxia longer than fully developed eggs. The results indicate that the increasing occurrence of anoxia in estuarine and coastal waters could have a major impact on the population growth of these important food web organisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349476
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  • 9
    Electronic Resource
    Electronic Resource
    Evolutionary relationships among deep-sea mytilids (Bivalvia: Mytilidae) from hydrothermal vents and cold-water methane/sulfide seeps (1995)
    Springer
    Marine biology 121 (1995), S. 477-485 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A protein electrophoretic survey of mytilids inhabiting deep-sea hydrothermal vents and cold-water methane/sulfide seeps revealed electromorph patterns diagnostic of 10 distinct species. From hydrothermal vents located at sites on the Galápagos Rift, the Mid-Atlantic Ridge, and the Mariana Back Arc Basin, we detected four species of mytilids. Six additional species were detected from three cold-water seep sides in the Gulf of Mexico. The patchy distribution and temporal stability of seeps may provide a greater opportunity for mytilid diversification and persistence than vent sites Nei's genetic distances (D) between species were relatively large (range: 0.528 to ∞) both within and among habitat types. This pronounced degree of genetic differentiation suggests a relatively ancient common ancestor for the group. Phylogenetic trees were generated using distance Wagner and parsimony analyses of allozyme and morphological characters. The tree topologies obtained from both methods support: (1) the hypothesis that a seep ancestor gave rise to the deep-sea hydrothermal vent mytilids, (2) a historical progression from shallow-water to deep-water habitats, and (3) a co-evolutionary progression from external to internal localization of bacterial symbionts. Whether the seep mytilid taxa constitute paraphyletic or polyphyletic groups remains unresolved. Our phylogenetic hypotheses also provide a benchmark for the phylogeny of mytilid bacterial symbionts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349456
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  • 10
    Electronic Resource
    Electronic Resource
    Extensive gene flow among mytilid (Bathymodiolus thermophilus) populations from hydrothermal vents of the eastern Pacific (1995)
    Springer
    Marine biology 124 (1995), S. 137-146 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Prior studies of the hydrothermal vent mussel Bathymodiolus thermophilus (Bivalvia: Mytilidae), provided conflicting predictions about the dispersal ability and population structure of this highly specialized species. Analyses of morphological features associated with its larval shells revealed a feeding larval stage that might facilitate dispersal between ephemeral vent habitats. In contrast, an allozyme study revealed substantial genetic differentiation between samples taken from populations 2370 km apart on Galápagos Rift (Latitude 0°N) and the East Pacific Rise (13°N). To resolve the discrepancy between these studies, we examined allozyme and mitochondrial (mt) DNA variation in new samples from the same localities plus more recently discovered sites (9° and 11°N) along the East Pacific Rise. Although analysis of 26 enzyme-determining loci revealed relatively low levels of genetic variation within the five populations, no evidence existed for significant barriers to dispersal among populations. We estimated an average effective rate of gege flow (Nm) of ≃ 8 migrants per population per generation. Two common mtDNA variants predominated at relatively even frequencies in each population, and similarly provided no evidence for barriers to gene flow or isolation-by-distance across this species' known range. Larvae of this species appear to be capable of dispersing hundreds of kilometers along a continuous ridge system and across gaps separating non-contiguous spreading centers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349155
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