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  • Springer  (612)
  • 2000-2004  (213)
  • 1985-1989  (387)
  • 1955-1959  (12)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Landscape ecology 15 (2000), S. 99-114 
    ISSN: 1572-9761
    Keywords: bird distributions ; Monte Carlo ; nearest neighbor ; point patterns ; randomization ; spatial pattern ; spatial statistics ; test of randomness
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This paper presents a nearest neighbor method for the spatial analysis of data collected from discrete field sampling sites. The method was applied to point counts of birds at permanent survey sites in the Nicolet National Forest of northeastern Wisconsin. The spatial analysis method we developed uses a Monte Carlo randomization approach to test for non-randomness not only of the mean nearest neighbor distance between n points but also the mean second nearest, third nearest,..., to (n−1)th nearest distances to reveal spatial information at multiple scales. Because the bird survey sites are not randomly distributed throughout the forest, the survey sites at which a given species was recorded were compared with random samples drawn from the total survey sites rather than from all possible points within the forest. More refined analyses restricted the randomization by (a) habitat type, in order to separate the effects of non-randomly distributed habitat types on species' distributions; and (b) north-south regions of the forest, in order to account for regional gradients in distribution which were evident for some species. Spatial patterns among the sites at which the birds were detected reveal information about the scale at which the birds are distributed in their environment and provide a more complete picture of multi-scale bird population dynamics.
    Type of Medium: Electronic Resource
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  • 2
    Publication Date: 2004-07-01
    Print ISSN: 0169-4286
    Electronic ISSN: 1573-5095
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Published by Springer
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Bulletin of mathematical biology 62 (2000), S. 1001-1001 
    ISSN: 1522-9602
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Bulletin of mathematical biology 62 (2000), S. 675-694 
    ISSN: 1522-9602
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract Mean fitness is non-decreasing in the symmetry sector of the frequency trajectory followed in competitive replication at sublinear propagation rates (parabolic time course). This sector contains the pairwise symmetric distribution of species frequencies and its neighboring states, and represents at least half the possible states of an evolving sublinear system. States in the non-symmetry sector produce a negative rate of change in mean fitness. The heterogeneous steady state attained in a finite sublinear system is destabilized by formation of a variant with above-threshold fitness. Evolution in the post-steady-state interval elevates the fitness threshold for coexistence. Contrary to the proposition that ‘parabolic growth invariably results in the survival of all competing species’, only species with sufficient fitness to avoid subthreshold fitness survive.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1476-5535
    Keywords: Aflatoxin miniassay ; Fluorescence analysis ; Aspergillus flavus ; Aspergillus parasiticus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary A convenient miniassay for aflatoxin has been developed for cultures ofAspergillus flavus andA. parasiticus grown for 3–10 days in 10 ml of a coconut extract medium. The sensitivity of the assay, as measured by photofluorometry (365 nm maximum excitation; 445 nm maximum emission), is of the order of 0.01 μM (3.12 ng/ml) for aflatoxin B1 dissolved in aqueous iodine (0.26 mM). High performance liquid chromatography, monitored by fluorometric analysis of both an aflatoxin B1 standard and selected culture filtrates, confirmed the sensitivity of the assay and indicated specificity for iodine-enhanced fluorescence of aflatoxin in the coconut extract medium. Thin layer chromatography further confirmed the aflatoxin titers and the specificity for enhancement of aflatoxins B1 and G1 in culture filtrates.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of plant growth regulation 19 (2000), S. 306-313 
    ISSN: 1435-8107
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Stochastic environmental research and risk assessment 3 (1989), S. 97-110 
    ISSN: 1436-3259
    Keywords: ARMA processes ; fractionally differencedARMA processes ; long memory ; spectral density ; maximum likelihood estimates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract A class of regression type estimators of the parameterd in a fractionally differencedARMA (p, q) process is introduced. This class is an extension of the estimator considered by Geweke and Porter-Hudak. In a simulation study, we compared three estimators from this class together with two approximate maximum likelihood estimators which are based on two separate approximations to the likelihood. One approximation ignores the determinant term in the likelihood and the other includes a compensating factor for the determinant. When the determinant term is included, the estimate tends to be much less biased and is in general superior to the other estimate. The approximate maximum likelihood estimator out performed, by a large margin, the regression type estimators for pureARIMA (0,d,0) processes. However, forARIMA (1,d,1) processes, a regression type estimator turned out to be the best for realizations of length 400 in 3 out of the 5 cases we tried.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Computing 38 (1987), S. 299-313 
    ISSN: 1436-5057
    Keywords: 65D05 ; 41A10 ; Interpolation ; local piecewise polynomials ; ratio slope
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Ein Satz diskreter Datenwerte über dem Intervall [a, b], der eine Funktiong (x) repräsentiert, wird stückweise durch lokal definierte kubische Polynome interpoliert. Die entstehende Interpolationsfunktion hat folgende Eigenschaften: sie ist monoton und/oder konvex und repräsentiert alle durch die Daten vorgegebenen Wendepunkte, wobei keine zusätzlichen Wendepunkte erzeugt werden. Das Approximationsverfahren wird in Form eines FORTRAN 77-Unterprogramms angegeben.
    Notes: Abstract The interpolation of a discrete set of data, on the interval [a, b], representing the functiong(x) is obtained using a local piecewise polynomial of order 3. This piecewise cubic interpolant has the following properties: monotonicity and/or convexity or turning points that are present in the data are preserved and no extraneous turning points are created. This approximation method is also presented in the form of a FORTRAN77 subroutine.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1435-604X
    Keywords: Mathematical model ; Laser surgery ; Optical fibres ; Tumours ; Thermal diffusion ; Multiple fibres
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics , Technology
    Notes: Abstract A mathematical model is employed to discuss the region treated by local hyperthermia, when the source of heat is a laser whose energy is directed into the treatment region through four optical fibres ending at the corners of a square. If treatment is over a period that is substantially longer than the time for the temperature distribution to reach equilibrium, a steady state model using four point sources can be employed to obtain a general idea of the temperatures reached and the region treated for different power levels and sizes of square. For shorter times, and for more accurate estimation of the regions treated, numerical calculation on a computer is essential. The details of the calculation depend on individual cases, but we demonstrate here that such computations are possible, and present a series of typical results. A comparison is made with the results of a series of experiments on canine liver, showing that it is possible to obtain good qualitative and numerical agreement.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Optical and quantum electronics 18 (1986), S. 93-96 
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Type of Medium: Electronic Resource
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