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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Plant ecology 74 (1988), S. 143-150 
    ISSN: 1573-5052
    Keywords: Aggregation ; Forest-structure ; Gap dynamics ; Landscape ; Succession
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An individual tree-based forest succession model was modified to simulate a forest stand as a grid of contiguous 0.01-ha cells. We simulated a 9 ha stand for 750 years and sampled the stand at 50 yr intervals, outputting structural variables for each grid cell. Principal components analysis was used to depict temporal patterns in forest structure as observed in 0.01 ha samples (individual grid cells). We then resampled the grid using square aggregates of 4 to 100 grid cells as quadrats. Principal component scores recalculated for the aggregates, using the original (0.01 ha scale) scoring matrix, depict the effects of obervational scale on perceived patterns in forest structure. Larger quadrats reduce the apparent variation in forest structure and decrease the apparent rate of structural dynamics. Results support a scale-dependent conceptualization of forest systems by illustrating the qualitative difference in forest dynamics as viewed at the scale of individual gap elements as compared to the larger scale steady state mosaic. The aggregation exercise emphasizes the relationship between these two observational scales and serves as a general framework for understanding scaling relationships in ecological phenomena.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-2592
    Keywords: Acid-labile α-interferon ; human T-cell leukemia/lymphoma virus I ; Epstein-Barr virus ; systemic lupus erythematosus ; acquired immune deficiency syndrome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract B-cell lines were established as spontaneous outgrowths of cell cultures from patients with adult T-cell leukemia (ATL). Three such lines were shown to have integrated human T-cell leukemia/lymphoma virus 1 (HTLV-I) proviral sequences as well as Epstein-Barr virus (EBV) infection. Supernatant fluids from these cultured cells were assayed for interferon (IFN) production. Acid-stable α-IFN was found to be produced by one cell line (CF), and acid-labile α-IFN by the other two (HS, MJB). In contrast, HTLV-I-infected T-cell lines did not produce IFN. Some EBV-infected B-cell lines produce acid-labile α-IFN, while others do not. Since α-IFN, both acid stable and acid labile, is found in sera from patients with the polyclonal activation of B cells as a constitutive part of the disease, the above observations suggest a possible role of polyclonal B-cell activation in α-IFN production in these diseases.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 24 (1989), S. 733-736 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The liquid SIMS mass spectra of silver acetate dissolved in a glycerol matrix is discussed, with emphasis on the formation of a ‘silver mirror’ on the surface of the glycerol droplet owing to reduction of the silver acetate. Silver clusters containing up to three silver atoms have been observed from this mirrored surface; Ag3+ cluster ions are not observed in the spectrum when conditions are such that the mirror is not formed. For example, use of a slightly oxidizing matrix (o-nitrophenyl octyl ether or m-nitrobenzylalcohol) prevents formation of the ‘mirror’; only Ag+ is sputtered from this surface.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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