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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 86 (1993), S. 36-41 
    ISSN: 1432-0533
    Keywords: Alzheimer's disease ; β/A4 deposits ; Morphological types ; Spatial pattern ; Clustering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The spatial patterns of diffuse, primitive, classic (cored) and compact (burnt-out) subtypes of β/A4 deposits were studied in coronal sections of the frontal lobe and hippocampus, including the adjacent gyri, in nine cases of Alzheimer's disease (AD). If the more mature deposits were derived from the diffuse deposits then there should be a close association between their spatial patterns in a brain region. In the majority of tissues examined, all deposit subtypes occurred in clusters which varied in dimension from 200 to 6400 μm. In many tissues, the clusters appeared to be regularly spaced parallel to the pia or alveus. The mean dimension of the primitive deposit clusters was greater than those of the diffuse, classic and compact types. In about 60% of cortical tissues examined, the clusters of primitive and diffuse deposits were not in phase, i.e. they alternated along the cortical strip. Clusters of classic deposits appeared to be distributed independently of the diffuse deposit clusters. Cluster size of the primitive deposits was positively correlated with the density of the primitive deposits in a tissue but no such relationship could be detected for the diffuse deposits. This study suggested that there was a complex relationship between the clusters of the different subtypes of β/A4 deposits. If the diffuse deposits do give rise to the primitive and classic varieties then factors unrelated to the initial deposition of β/A4 in the form of diffuse plaques were important in the formation of the mature deposits.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Annals of operations research 5 (1986), S. 463-484 
    ISSN: 1572-9338
    Keywords: Branch and bound design ; tree enumeration strategies ; discrete nonlinear programs ; nonlinear integer test problems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Notes: Abstract This paper is concerned with computational experimentation leading to the design of effective branch and bound algorithms for an important class of nonlinear integer programming problems, namely linearly constrained problems, which are used to model several real-world situations. The main contribution here is a study of the effect of node and branching variable selection and storage reduction strategies on overall computational effort for this class of problems, as well as the generation of a set of adequate test problems. Several node and branching variable strategies are compared in the context of a pure breadth-first enumeration, as well as in a special breadth and depth enumeration combination approach presented herein. Also, the effect of using updated pseudocosts is briefly addressed. Computational experience is presented on a set of eighteen suitably-sized nonlinear test problems, as well as on some random linear integer programs. Some of the new rules proposed are demonstrated to be significantly superior to previously suggested strategies; interestingly, even for linear integer programming problems.
    Type of Medium: Electronic Resource
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