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  • 1
    Electronic Resource
    Electronic Resource
    Coordinate rings of topological Klingenberg planes I: The affine perspective (1995)
    Springer
    Geometriae dedicata 58 (1995), S. 101-116 
    Details
    ISSN: 1572-9168
    Keywords: 51E15 ; 54H13
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract Although the coordinate ternary field of a topological affine plane is topological, the converse does not hold. However, an affine plane is topological precisely when its coordinate biternary fields are topological. We extend this result to topological biternary rings and their topological affine Klingenberg planes. Then we examine the locally compact situation. Finally, following the ideas of Knarr and Weigand, we show that in certain circumstances, the continuity of the ternary operators is sufficient to ensure that the biternary ring is topological. This facilitates the construction of locally compact, locally connected affine Klingenberg planes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01263480
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  • 2
    Electronic Resource
    Electronic Resource
    The sensory basis of rheotaxis in the blind Mexican cave fish, Astyanax fasciatus (1999)
    Springer
    Journal of comparative physiology 184 (1999), S. 519-527 
    Details
    ISSN: 1432-1351
    Keywords: Key words Lateral line ; Rheotaxis ; Olfactory ; Cave fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The sensory basis of rheotaxis (orientation to currents) was investigated in the blind Mexican cave fish, Astyanax fasciatus. An unconditioned rheotactic response to uniform velocity flows was exhibited, with a threshold of less than 3 cm s−1. Disabling the entire lateral line or the superficial neuromast receptor class increased the rheotactic threshold to greater than 9 cm s−1. A pharmacological block of the lateral line canal system alone had no effect. These results demonstrate that the superficial lateral line system controls rheotaxis at low current velocities. The effect of pairing an odor stimulant with the water current dropped the rheotactic threshold to less than 0.4 cm s−1. This study provides a clear behavioral role for the superficial neuromasts where none previously existed, and also establishes a link between the mechanosensory lateral line and olfactory systems in the olfactory search behavior of the cave fish.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003590050351
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  • 3
    Electronic Resource
    Electronic Resource
    Population variation in the mitochondrial cytochrome b gene of the orange roughy Hoplostethus atlanticus and the hoki Macruronus novaezelandiae (1995)
    Springer
    Marine biology 122 (1995), S. 503-509 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To describe the genetic relationship among regional populations of two commercially valuable species of marine fish, the orange roughy Hoplostethus atlanticus and the hoki Macruronus novaezelandiae, the mitochondrial (mt) DNA haplotypes of 59 individuals were defined by direct sequencing of the cytochrome b gene. Samples of orange roughy were collected on four fishing grounds around New Zealand, one off the west coast of Tasmania and one near South Africa from 1990–1991. Samples from hoki were collected on three fishing grounds around New Zealand and one off Tasmania during the same period. An average of 252 nucleotides were sequenced from each of 32 orange roughy and an average of 372 nucleotides from each of 27 hoki. Sequence variation allowed the definition of 9 unique orange roughy haplotypes and 5 hoki haplotypes. Genetic variation, as measured by both average sequence divergence and haplotype diversity, was high in the orange roughy (nucleotide diversity=0.590%, haplotype diversity=0.782) and low in the hoki (nucleotide diversity=0.076%, haplotype diversity=0.279) relative to a similar survey of the Atlantic cod, Gadus morhua. Differences in haplotype frequencies of orange roughy from New Zealand, Tasmania and South Africa were not significant, and the most common haplotype was found in similar frequencies in these three geographically distant regions. Differences in haplotype frequencies between the New Zealand and Tasmanian samples of hoki were significant, suggesting restricted gene flow between these two regions. The contrasting patterns of low but regionally subdivided genetic variation in the hoki versus high but geographically undifferentiated genetic variation in the orange roughy may be attributed to the low fecundity, slow maturation and long lifespan of the orange roughy relative to the hoki.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00350673
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  • 4
    Electronic Resource
    Electronic Resource
    Distribution and diversity of mtDNA lineages among southern right whales (Eubalaena australis) from Australia and New Zealand (1999)
    Springer
    Marine biology 134 (1999), S. 1-7 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Using a biopsy dart system, samples of skin tissue were collected from southern right whales (Eubalaena australis) in 1995 on two wintering grounds, southwest Australia (n = 20) and the Auckland Islands of New Zealand (n = 20); and on offshore feeding grounds at Latitudes 40 to 43°, south of Western Australia (n = 5). A variable section of the mitochondrial DNA control-region (289 nucleotides) was amplified and sequenced from these 45 individuals (21 males, 20 females and 4 of unknown sex), distinguishing a total of seven unique sequences (i.e. mtDNA haplotypes). Two haplotypes were found on both wintering grounds (including a common type representing 45% of each sample), and five types were unique to only one wintering ground. An analysis of variance adapted for molecular information revealed significant genetic differentiation between the two wintering grounds (p = 0.017). The feeding-ground sample was too small for statistical comparison with the wintering grounds, but included two haplotypes found only in the Auckland Islands as well as the common haplotype found on both wintering grounds. The nucleotide diversity and differentiation of mtDNA among the right whales was similar to that among humpback whales (Megaptera novaeangliae) from the same regions (Baker et al. 1998), but haplotype diversity was significantly reduced, perhaps as a result of more intensive hunting during the last century and continued illegal hunting during this century.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002270050519
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  • 5
    Electronic Resource
    Electronic Resource
    Large-scale production of chlamydospores of Gliocladium virens strain GL-21 in submerged culture (1997)
    Springer
    Journal of industrial microbiology and biotechnology 19 (1997), S. 163-168 
    Details
    ISSN: 1476-5535
    Keywords: Keywords: biological control; antagonist; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: SoilGard™ is a commercial microbial fungicide containing chlamydospores of Gliocladium virens strain GL-21. The formulation is registrated with the US Environmental Protection Agency (EPA) by Thermo Trilogy Corporation, Columbia, Maryland. The biocontrol agent was developed in cooperation with the Biocontrol of Plant Diseases Laboratory (BPDL), US Department of Agriculture (USDA), and is targeted for controlling damping-off diseases caused by Rhizoctonia solani and Pythium ultimum in vegetable and ornamental greenhouses. Formulation requires production of chlamydospore biomass in liquid fermentation which was carried out in 20-L, 1500-L and 4000-L submerged liquid fermentors. Key economic process parameters, fermentation kinetics and the reproducibility of the fermentation at this scale were evaluated and analyzed. Starter culture quality and maturity of chlamydospores were identified as key issues for obtaining successful fermentations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/sj.jim.2900430
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  • 6
    Electronic Resource
    Electronic Resource
    Leaflet development, induction time, and medium influence somatic embryogenesis in peanut (Arachis hypogaea L.) (1998)
    Springer
    Plant cell reports 17 (1998), S. 925-929 
    Details
    ISSN: 1432-203X
    Keywords: Key words Somatic embryogenesis ; Peanut ; Arachis hypogaea ; Leaflets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Factors affecting somatic embryogenesis in peanut (Arachis hypogaea L.) using leaflet explants of seedlings obtained from aseptically germinated embryo axes were evaluated. Somatic embryogenesis was influenced by developmental stage, leaflet size, induction medium, and time on induction medium. Leaflets that were 5–7 mm long had a greater embryogenic response than smaller or larger leaflets. Percent embryogenesis and mean number of embryos were related to the developmental stage of germinating seedlings. A greater response was obtained if leaflets were folded and closely appressed. Preselection of leaflets increased percent embryogenesis from 21% up to 67%. As leaflets unfolded, embryogenesis decreased; open leaflets lost the potential for embryogenesis. The optimal induction conditions were a 7-day incubation period on Murashige and Skoog medium with 136 μm 2,4-dichlorophenoxyacetic acid and 0.93 μm kinetin. Somatic embryos germinated to form plants that exhibited a normal morphology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002990050511
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  • 7
    Electronic Resource
    Electronic Resource
    Modelling and analysis of time-lags in some basic patterns of cell proliferation (1998)
    Springer
    Journal of mathematical biology 37 (1998), S. 341-371 
    Details
    ISSN: 1432-1416
    Keywords: Key words: Cell proliferation ; Mathematical modelling ; Time-lag ; Neutral delay differential equation ; Sensitivity analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract.  In this paper, we present a systematic approach for obtaining qualitatively and quantitatively correct mathematical models of some biological phenomena with time-lags. Features of our approach are the development of a hierarchy of related models and the estimation of parameter values, along with their non-linear biases and standard deviations, for sets of experimental data. We demonstrate our method of solving parameter estimation problems for neutral delay differential equations by analyzing some models of cell growth that incorporate a time-lag in the cell division phase. We show that these models are more consistent with certain reported data than the classic exponential growth model. Although the exponential growth model provides estimates of some of the growth characteristics, such as the population-doubling time, the time-lag growth models can additionally provide estimates of: (i) the fraction of cells that are dividing, (ii) the rate of commitment of cells to cell division, (iii) the initial distribution of cells in the cell cycle, and (iv) the degree of synchronization of cells in the (initial) cell population.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002850050133
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  • 8
    Electronic Resource
    Electronic Resource
    A Note on the Decomposition of Continuity (1997)
    Springer
    Acta mathematica hungarica 75 (1997), S. 245-251 
    Details
    ISSN: 1588-2632
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006503422645
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  • 9
    Electronic Resource
    Electronic Resource
    Monitoring the rate of oxygen consumption in plant cell suspensions (1997)
    Springer
    Plant cell, tissue and organ culture 51 (1997), S. 111-117 
    Details
    ISSN: 1573-5044
    Keywords: Nicotiana tabacum ; oxidative burst ; oxygen electrode ; Pseudomonas solanacearum ; Pseudomonas syringae ; respiratory burst ; Solanumtuberosum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A method is described that allows the rate of oxygen consumption to be monitored in plant cell suspensions. The method utilized oxygen electrodes placed in beakers of plant cells subjected to various treatments. The voltage readings from calibrated electrodes were converted to % oxygen (100% equals air equilibration) and the rate of oxygen consumption was estimated by calibration graphs made with no cells present. This system simultaneously monitors one to sixteen or more samples, allowing comparison of treatments on identically treated cells. We have used this method to study the respiratory burst of plant cells produced in response to viable or heat-killed bacteria. Because the system was computer-monitored and open to the atmosphere, data could be collected over several hours. Various factors that affected the measurement of dissolved oxygen concentration with this technique were explored and considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005997126293
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  • 10
    Electronic Resource
    Electronic Resource
    First observations of Pontecorvo reactions with a recoiling neutron (1995)
    Springer
    The European physical journal 351 (1995), S. 325-331 
    Details
    ISSN: 1434-601X
    Keywords: 25.43
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We report the first observations of Pontecorvo reactions of the type ¯pd →Xn. We fully reconstruct the outgoing meson and, for antiprotons stopped in liquid deuterium, we measure: BR(¯pd→π0)=(7.03±0.72)×10−6, BR(¯pd→ηn)=(3.19+0.48)×10−6, BR(¯pd→ωn)=(22.8+4.1)×10−6, BR(¯pd→η′n)14×10−6 (at 95% confidence level). Assuming charge independence, our result for¯ pd→π0n is compatible with measurements of the only other observed Pontecorvo reaction ¯pd → π−p. The experimental ratios between the above branching ratios are in fair agreement with both the statistical model and dynamical two-step models (assumingN¯ N annihilation into two mesons, with subsequent absorption of one meson on the remaining nucleon). This agreement suggests that there may be appreciable rates for Pontecorvo reactions producing final state mesons with masses above 1 GeV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01290916
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