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  • 1
    Electronic Resource
    Electronic Resource
    Effects of turbidity and biotic factors on the rotifer community in an Ohio reservoir (1998)
    Springer
    Hydrobiologia 287-388 (1998), S. 215-223 
    Details
    ISSN: 1573-5117
    Keywords: reservoir ; Rotifera ; spatial distribution ; temporal variation ; turbidity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In reservoirs physical horizontal gradients may affect zooplankton distributions as well as the biotic interactions that potentially regulate zooplankton abundance and species composition. We examined patterns of rotifer abundance and population dynamics along a turbidity gradient over a 4-year period in an Ohio reservoir. To analyze the effect of turbidity on rotifer populations we compared rotifer abundance patterns, species composition, birth and death rates at two sites with high turbidity (river site) and low turbidity (dam site) conditions. Because of the potentially important biotic interaction between rotifers and cladocerans, we also compared cladoceran abundance patterns and species composition. Our results suggest no effect of turbidity on rotifers in Acton Lake. Rotifer and cladoceran abundance patterns were similar at low and high turbidity sites. Similarity indices revealed few differences in rotifer and cladoceran species composition between sites. Rotifer birth and death rates were also similar at low and high turbidity sites. In contrast to these homogeneous spatial patterns, among year comparisons indicate high temporal variability in all parameters measured. Mean rotifer densities were similar from 1993 to 1995, but in 1996 density increased 4-fold. Rotifer species assemblages were dominated by Brachionus spp. from 1993 to 1995, while Keratella cochlearis and Polyarthra spp. were numerically dominant in 1996. Mean cladoceran density also increased in 1996 compared to previous years. Cladoceran species composition was dominated by Diaphanosoma birgei from 1993 to 1995, while Daphnia parvula and Bosmina longirostris dominated the 1996 cladoceran community. Comparison of rotifer population parameters in years of contrasting D. parvula abundance suggests that exploitative competition may be an important mechanism regulating rotifer communities in Acton Lake. Interannual variation in Daphnia abundance may in turn be controlled by variation in fish biomass.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017041826108
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Effects of turbidity and biotic factors on the rotifer community in an Ohio reservoir (1998)
    Springer
    Hydrobiologia 387-388 (1998), S. 215-223 
    Details
    ISSN: 1573-5117
    Keywords: reservoir ; Rotifera ; spatial distribution ; temporal variation ; turbidity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In reservoirs physical horizontal gradients may affect zooplankton distributions as well as the biotic interactions that potentially regulate zooplankton abundance and species composition. We examined patterns of rotifer abundance and population dynamics along a turbidity gradient over a 4-year period in an Ohio reservoir. To analyze the effect of turbidity on rotifer populations we compared rotifer abundance patterns, species composition, birth and death rates at two sites with high turbidity (river site) and low turbidity (dam site) conditions. Because of the potentially important biotic interaction between rotifers and cladocerans, we also compared cladoceran abundance patterns and species composition. Our results suggest no effect of turbidity on rotifers in Acton Lake. Rotifer and cladoceran abundance patterns were similar at low and high turbidity sites. Similarity indices revealed few differences in rotifer and cladoceran species composition between sites. Rotifer birth and death rates were also similar at low and high turbidity sites. In contrast to these homogeneous spatial patterns, among year comparisons indicate high temporal variability in all parameters measured. Mean rotifer densities were similar from 1993 to 1995, but in 1996 density increased 4-fold. Rotifer species assemblages were dominated by Brachionus spp. from 1993 to 1995, while Keratella cochlearis and Polyarthra spp. were numerically dominant in 1996. Mean cladoceran density also increased in 1996 compared to previous years. Cladoceran species composition was dominated by Diaphanosoma birgei from 1993 to 1995, while Daphnia parvula and Bosmina longirostris dominated the 1996 cladoceran community. Comparison of rotifer population parameters in years of contrasting D. parvula abundance suggests that exploitative competition may be an important mechanism regulating rotifer communities in Acton Lake. Interannual variation in Daphnia abundance may in turn be controlled by variation in fish biomass.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017041826108
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Adaptive sampling of intracellular and extracellular cardiac potentials with the fan method (1987)
    Springer
    Medical & biological engineering & computing 25 (1987), S. 261-268 
    Details
    ISSN: 1741-0444
    Keywords: Action potentials ; Adaptive sampling ; Cardiac electrophysiology ; Data compression ; Electrograms fan algorithm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Uniform sampling rates of 5000 samples s−1 and 15000 samples s−1 or more are required to accurately represent intracellular and extracellular cardiac electrograms. These high rates are necessary because of short intervals where rapid deflections occur; thus uniform sampling results in far too many samples from slow phases when voltages change little between consecutive samples. Adaptive sampling with the fan algorithm selects samples with an irregular temporal spacing that specifies each waveform with the minimum number of samples required for a given maximum error or tolerance ε. This paper describes the performance of the fan as a function of tolerance on cardiac action potentials and electrograms simulated with the Beeler-Reuter model or measured directly from the heart, including examples showing signal quality, average sampling rate and intervals between samples. With low tolerances of ɛα = 100 μV (intracellular) or ɛα = 25 μV (extracellular), the average fan sampling rates were about 8000 samples s−1 for measured waveforms, and about 200 samples s−1 for simulated ones. With higher tolerances of ɛβ = 1 mV (intracellular) or ɛβ = 60 μV (extracellular) average fan sampling rates near 200 samples s−1 were found in all cases. The results suggest that good quality measurements of action potentials and electrograms can be obtained with remarkably low average sampling rates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02447422
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
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