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  • 1
    Electronic Resource
    Electronic Resource
    Adaptive significance of phytoplankton stickiness with emphasis on the diatom Skeletonema costatum (1995)
    Springer
    Marine biology 123 (1995), S. 667-676 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Diatom aggregate formation was analyzed using coagulation theory. Population dynamics models show that coagulation has an important impact on species succession during diatom blooms. When different species collide and form mixed aggregates this process causes interspecific interference competition within the diatom community. The outcome can be predicted by a set of simple differential equations. For a twospecies system the equations reduce to the Lotka-Volterra two-species competition model. The outcome of this interference competition depends on species-specific growth rates, cell sizes, stickiness and on the species composition of the seeding populations of a bloom. Due to mutual flocculation some species may disappear from the environment. Small and fast growing diatoms are favoured by high stickiness coefficients. The impact of stickiness on species succession was found to be most pronounced in eutrophic and hydrographically isolated environments. The sticking properties of the diatom Skeletonema costatum are discussed in an evolutionary context; we suggest that mutual coagulation increases the abundance of S. costatum relative to other diatom species in coastal areas. The model was tested on field data, and the predicted dynamics of a spring bloom was very similar to that observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349109
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  • 2
    Electronic Resource
    Electronic Resource
    Structural and electrical characteristics of Ge and Se implanted InP after rapid thermal annealing (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 2249-2255 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The electrical activation of Ge and Se implanted into 〈100(approximately-greater-than) InP at elevated temperatures and the annealing of the implantation-induced disorder have been investigated by differential Hall/resistivity measurements, Rutherford backscattering spectrometry, and transmission electron microscopy. At implantation temperatures below 170 °C, an amorphous layer is created by the implantation process. After recrystallization by rapid thermal annealing of the amorphized layer, a localized defect band was found, which gives rise to a dip (M shape) in the carrier density profile. This band is believed to be caused by a stoichiometric imbalance of In and P. For implantation temperatures above 170 °C, the samples remain crystalline during implantation and as a result, no localized defect band is observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.351618
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  • 3
    Electronic Resource
    Electronic Resource
    Evaluation of Methods for Nitrogen and Phosphorus Control in Sewage Effluents (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Water and environment journal 6 (1992), S. 0 
    Details
    ISSN: 1747-6593
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: The design parameters for the City of Copenhagen sewage-treatment works were established on an experimental basis, and parallel studies of six pilot plants were made over a two-year period. The key parameters are (a) the rate of nitrification and denitrification, (b) temperature, and (c) BOD: N ratio in the influent. The data obtained from different methods had to be normalized with respect to the fraction of nitrifiers, temperature, and concentrations of substrates in order to achieve consistent results. The results indicated a substantial inhibition of the nitrifiers, i.e. a 20–30% reduction of the reaction rate. Significant savings were made possible by a comprehensive analysis of the temperature conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1747-6593.1992.tb00706.x
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  • 4
    Electronic Resource
    Electronic Resource
    Structure and low-temperature thermal relaxation of ion-implanted germanium (2001)
    Chester : International Union of Crystallography (IUCr)
    Journal of synchrotron radiation 8 (2001), S. 773-775 
    Details
    ISSN: 1600-5775
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: The structure of implantation-induced damage in Ge has been investigated using high resolution extended X-ray absorption fine structure spectroscopy(EXAFS). EXAFS data analysis was performed with the Cumulant Method. For the crystalline-to-amorphous transformation, a progressive increase in bond-length was observed without the presence of an asymmetry in interatomic distance distribution (RDF). Beyond the amorphization threshold the RDF was dose dependent and asymmetric, where the bond-length and asymmetry increased as functions of ion dose. Such an effect was attributed to the formation of three- and five-fold coordinated atoms within the a morphous phase. Low-temperature thermal annealing resulted in structural relaxation of the amorphous phase as evidenced by a reduction in the centroid ,asymmetry and width of the RDF, as consistent with a reduction in the fraction of non four-fold coordinated atoms.The results have been compared to other EXAFS studies of amorphous Ge, and it issuggested thatthe range of bond-lengths reported therein is related to the sample preparation method and state of relaxation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0909049500012620
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  • 5
    Electronic Resource
    Electronic Resource
    Near Infrared Reflectance Spectroscopy Prediction and Heritability of Neutral Detergent-Soluble Fiber in Alfalfa (1999)
    Springer
    Crop science 39 (1999), S. 1265-1270 
    Details
    ISSN: 1435-0653
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Medicago sativa L.) with improved quality. Pectin is the main component of NDSF and is highly digestible, but the assay for NDSF is time-consuming. The objectives were (i) to determine the potential use of near infrared reflectance spectroscopy (NIRS) to predict NDSF concentration in alfalfa and (ii) to estimate NDSF heritability and gain from selection. Herbage was sampled five times across 2 yr from two populations of half-sib (HS) progeny tested at Ithaca, NY. Calibration equations were developed by multiple linear regression of laboratory values of NDSF on NIRS spectra. Samples from one harvest were assayed twice to compare extraction methods. Means of NDSF from 90- and 80%-ethanol extractions were 213.1 ± 7.21 and 179.5 ± 5.89 g kg-1, respectively. Assay standard deviations were low for both ethanol concentrations. Because a better calibration equation was obtained with the 80%-ethanol assay, all remaining samples were assayed by that technique. Standard errors of calibration were small, ranging from 4.71 to 7.54 g kg-1. Coefficients of multiple determination (R2) ranged from 0.72 to 0.97. Most heritability estimates for NDSF were significantly greater than zero, ranging from -0.03 ± 0.20 to 0.56 ± 0.17 and averaging 0.41. Expected gain from selection of parents based on HS progeny ranged from 4.6 to 19.0 g kg-1 and averaged 10.3 g kg-1. Selecting parents with higher NDSF concentrations predicted by NIRS evaluations of HS progenies may improve forage quality of alfalfa.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/
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  • 6
    Electronic Resource
    Electronic Resource
    Associations among Forage Quality Traits, Vigor, and Disease Resistance in Alfalfa (1999)
    Springer
    Crop science 39 (1999), S. 1271-1276 
    Details
    ISSN: 1435-0653
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Medicago sativa L.) breeding include improving forage quality and levels of disease resistance. Little is known about the associations between forage quality characteristics, including pectin (the main component of neutral detergent-soluble fiber [NDSF]), and disease resistance and vigor in alfalfa. Our objectives were to determine, in two alfalfa populations, the (i) correlations among NDSF and other forage quality traits; (ii) correlations of forage quality traits with plant persistence, vigor, and levels of resistance to diseases; and (iii) heritabilities and expected gains from selection for the aforementioned traits. Simple, phenotypic, and additive genetic correlation coefficients were estimated from half-sib (HS) progeny tests of two alfalfa populations (NY9505 and NY9515). In both populations, NDSF was negatively correlated with acid detergent fiber (ADF), lignin, and neutral detergent fiber (NDF), and positively correlated with true in vitro dry matter digestibility (IVDMD). Vigor was positively correlated with ADF, lignin, and NDF, and negatively correlated with IVDMD and crude protein (CP) only in NY9515. Of 144 correlation coefficients computed between forage quality traits and resistances to five major alfalfa diseases, only six were significant, and they were low in magnitude (-0.22 ± 0.11 to 0.30 ± 0.14). In an alfalfa improvement program, selection for forage quality is not expected to indirectly affect levels of disease resistance, but it may reduce vigor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/
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  • 7
    Electronic Resource
    Electronic Resource
    Mechanism of emulsion polymerization of styrene with persulfate as activator in the absence and presence of mercaptan and a retarderThe work discussed herein was performed as a part of the research project sponsored by the Reconstruction Finance Corporation, Office of Synthetic Rubber, in connection with the Government Synthetic Rubber Program. (1955)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 15 (1955), S. 459-473 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: With the use of persulfate containing radioactive sulfur it is shown that the termination reaction of the polymerization of styrene is a coupling of the free radical chains. In the presence of m-dinitrobenzene as a retarder evidence has been presented that the termination reaction is a disproportionation and not a combination of two free radical chains. Mercaptan in the emulsion polymerization of styrene acts solely as a chain transfer agent. Any chemical reaction between persulfate and mercaptan does not contribute to the initiation. In the presence of detergent the rate of initiation of the polymerization of styrene is equal to the rate of thermal dissociation of persulfate: \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm S}_2 {\rm O}_{\rm 8}^{ - - } \to 2{\rm SO}_4 ^ - . $\end{document} Thus, any reaction between persulfate with monomer and detergent does not contribute to the initiation. The much smaller rate of initiation in the absence of detergent is attributed to the slight solubility of styrene, the concentration of the monomer being so small that it cannot capture all the free radicals. The effect of the detergent is a physical one, by its solubilizing action it increases the solubility of the monomer in the water layer to such an extent that the “activator” now becomes 100% efficient.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1955.120158012
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