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  • 1
    Electronic Resource
    Electronic Resource
    Constant-Temperature Steam-Distillation Apparatus for Isolation of Fluorine (1947)
    s.l. : American Chemical Society
    Analytical chemistry 19 (1947), S. 154-156 
    Details
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ac60003a005
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  • 2
    Electronic Resource
    Electronic Resource
    Multiplexed single-photon counting. I. A time-correlated fluorescence lifetime camera (1996)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 2228-2237 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We report the operation of a new type of fluorescence lifetime imaging camera based on the time-correlated single-photon counting (TCSPC) technique. To the best of our knowledge the application-specific integrated circuit (ASIC) used in the camera is the first ASIC designed for the field of fluorescence. The ASIC also forms the basis for the first read-out system for single-photon timing array detectors and is capable of multiplexing and routing counts from up to sixteen detection channels, while preserving their timing characteristics with picosecond resolution. In conjunction with an array detector such as a multianode MCP-PM this ASIC allows multiple fluorescence decays to be routinely and simultaneously acquired using a single set of TCSPC timing electronics. To demonstrate one practical application of this technology, we have observed for the first time the spatial distribution of fluorescence lifetime contours through a strongly self-absorbing sample, and the effects observed demonstrate how differences in optical geometry can contribute to the lack of consistency between results obtained in different laboratories. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1147041
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  • 3
    Electronic Resource
    Electronic Resource
    Periphyton removal related to phosphorus and grazer biomass level (1999)
    Oxford, UK : Blackwell Science, Ltd
    Freshwater biology 41 (1999), S. 0 
    Details
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 1. The proliferation of nuisance periphyton in enriched streams may be dependent on the biomass of the grazing macroinvertebrates present. In the present study, the effectiveness of grazer size and biomass in controlling periphyton and the extent to which grazing effectiveness was affected by enrichment level were determined.2. Two sets of experiments with two caddisfly grazers were conducted in laboratory channels during spring and summer 1995 and 1996. The first set tested the combined effect of phosphorus enrichment and grazing, while the second set tested the effect of variable grazer biomass on periphyton biomass.3. Grazing reduced periphyton biomass in excess of 80%, compared to ungrazed controls. Grazers were equally effective in controlling filamentous green algae, Stigeoclonium, diatoms and small colonial greens. Near complete removal of periphyton biomass by grazing occurred at even at the lowest grazer biomass level (750 mg m−−2, i.e. approximately one-third of natural levels).4. Grazing controlled periphyton biomass more than did enrichment with soluble reactive phosphorus (SRP).5. Grazing rates in the phosphorus-grazing interaction experiments averaged about 6 mg chl a g invertebrate−−1 day−−1, which was similar to past work in these channels and elsewhere, while rates were about five-fold higher in the variable grazer biomass experiments.6. Simulating effects of SRP and grazing with a calibrated model suggests that higher SRP levels would be necessary to exceed a nuisance periphyton biomass level if grazers were present. However, if grazer biomass was more than 1500 mg m−−2, a nuisance level would probably not be exceeded at any SRP.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2427.1999.00405.x
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  • 4
    Electronic Resource
    Electronic Resource
    Studies on the mechanism of oxidative phosphorylation - IV. Pyridine nucleotide binding and its relation to activity in heart mitochondria
    Amsterdam : Elsevier
    BBA - Biochimica et Biophysica Acta 29 (1958), S. 103-112 
    Details
    ISSN: 0006-3002
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0006-3002(58)90150-1
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  • 5
    Electronic Resource
    Electronic Resource
    EFFECTIVENESS OF ALUM IN A WEEDY, SHALLOW LAKE (1986)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Water Resources Association 22 (1986), S. 0 
    Details
    ISSN: 1752-1688
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: : An alum treatment in Long Lake (mean depth, 2 m) in 1980 has been effective at controlling internal loading of phosphorus for four years. The fifth summer after treatment, the lake returned to its pro-treatment state. Lake P content decreased from a summer average of 65 μg/L during 1976–1978 to about 30 μg/L during four years following treatment. In 1985, summer P content was 61 μg/L. Algal abundance, species composition, and transparency have responded proportionately with P.Alum effectiveness apparently declined because the floe layer tended to sink and become dispersed at a deeper level in the sediment, as well as become covered with new, P-rich sediment. Iron-reduction may be the principal mechanism for internal P loading, although the lake is unstratified and anoxia is usually not pronounced.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1752-1688.1986.tb00764.x
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  • 6
    Electronic Resource
    Electronic Resource
    ALUM CONTROL OF INTERNAL PHOSPHORUS LOADING IN A SHALLOW LAKE (1982)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Water Resources Association 18 (1982), S. 0 
    Details
    ISSN: 1752-1688
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: : Alum treatment of a shallow lake, with mean depth 2 m and area 137 ha, curtailed internal loading of P for at least one ear. Mean summer total P and chl a decreased from 76 and 27μg l−1, respectively, in 1978 before treatment. to 29 and 14 μ l−1, while mean summer Sed transparency increased from 1.6 to 2.2 m and blue green algae were no longer dominant. Macrophyte biomass and distribution retuned during the post-alum year, 1980-1981, to previous levels after a 1979 four-month lake level drawdown had reduced biomass by 84 percent The improved transparency, resulting from the decrease in chl a following treatment, could encourage greater biomass of macrophytes in the deeper area of the lake. Recovery of macrophyte biomass to predrawdown levels may restore internal loading of P through enrichment of deep water sediments during winter dieback and decomposition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1752-1688.1982.tb00097.x
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  • 7
    Electronic Resource
    Electronic Resource
    The uptake, translocation and release of phosphorus by Elodea densa (1984)
    Springer
    Hydrobiologia 111 (1984), S. 43-48 
    Details
    ISSN: 1573-5117
    Keywords: phosphorus cycling ; macrophytes ; absorption ; sediment phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Short-term (16 h) laboratory studies of 32P uptake by Elodea densa rooted in sediment demonstrated both foliar and root uptake, and that translocation occurred acropetally and basipetally. Root absorption is projected to provide 83–85% of total phosphorus uptake during 12–16 h photoperiod days. Measured foliar uptake and excretion rates suggest that there would be no net leakage of phosphorus into the water by undamaged actively-growing E. densa. Foliar uptake decreased and root uptake increased in the dark relative to rates under light.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00007379
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  • 8
    Electronic Resource
    Electronic Resource
    Nuisance biomass levels of periphytic algae in streams (1988)
    Springer
    Hydrobiologia 157 (1988), S. 161-168 
    Details
    ISSN: 1573-5117
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Relative coverage of filamentous periphytic algae increased with chlorophyll a (chl a) biomass on natural substrata in 22 northwestern United States and Swedish streams. A biomass range of 100–150 mg chl a m−2 may represent a critical level for an aesthetic nuisance; below those levels, filamentous coverage was less than 20%. Other indices of water quality (dissolved oxygen content and measures of benthic macroinvertebrate diversity) were apparently unaffected by periphytic biomass or filamentous coverage in these streams. Neither was biomass related to limiting nutrient content (soluble reactive phosphorus, SRP), as has been observed in previous experiments using bare rocks in streams and slides in artificial channels. Ambient SRP concentration may not be a useful predicter of periphyton accrual on natural substrates, due to uptake and recycling of P throughout the stream and undetermined losses such as sloughing and grazing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00006968
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  • 9
    Electronic Resource
    Electronic Resource
    Dominance of phosphorus over nitrogen as the limiter to phytoplankton growth rate (1978)
    Springer
    Hydrobiologia 57 (1978), S. 209-215 
    Details
    ISSN: 1573-5117
    Keywords: Phosphorus ; growth rate ; phytoplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Laboratory experiments with natural phytoplankton assemblages from three lakes (two mesotrophic and one oligotrophic) showed that added PO4 predictably affected growth rate (µ, determined as P : B) while NO3 had little effect even when the N P ratio approached one. The response to PO4 followed the typical Monod-type function. The lack of effect of NO3 on µ at such low N : P ratios is in striking contrast to the added effect of NO3 Plus PO4 on maximum biomass produced versus only PO4 alone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00014575
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  • 10
    Electronic Resource
    Electronic Resource
    Plankton secondary productivity and biomass: Their relation to lake trophic state (1976)
    Springer
    Hydrobiologia 50 (1976), S. 129-144 
    Details
    ISSN: 1573-5117
    Keywords: secondary production ; biomass ; energy transfer ; P-B ratio
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The biomass and production of the most important zooplankton species were followed for two years in three lakes of varying trophic status in the Lake Washington watershed. Cladocerans and copepods were of equal importance in the biomass of lakes Findley and Chester Morse (both oligotrophic), whereas, copepods were the main biomass component in Lake Sammamish (mesotrophic). Cladocerans dominated production in lakes Sammamish and Chester Morse, while in Findley Lake their productive role, like that of biomass, was equal to that of the copepods. Rotifers contributed a relatively small biomass and production. Data from this study supported Hillbricht-Ilkowska's postulate that the energy transfer efficiency between the primary and secondary trophic levels decreases with increasing trophic state. Energy transfer efficiencies for the lakes of this study expressed as a two year mean of the ratio-secondary: primary production, were as follows: Findley Lake-0.13; Chester Morse Lake-0.08; and Lake Sammanish-0.04. On the other hand, the hypothesis of Patalas that the secondary productivity: biomass ratio (P/B) tended to increase in proportion to the productivity of a lake, could not be supported. Lake Sammamish, the most productive of the lakes studied, had a P/B ratio of 0.03 while lakes Findley and Chester Morse had P/B ratios of 0.04.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00019816
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