Maxima of discretely sampled random fields, with an application to 'bubbles'

A smooth Gaussian random field with zero mean and unit varianceis sampled on a discrete lattice, and we are interested in theexceedance probability or P-value of the maximum in a finiteregion. If the random field is smooth relative to the mesh size,then the P-value can be well approximated by results for thecontinuously sampled smooth random field (Adler, 1981; Worsley,1995a; Taylor & Adler, 2003; Adler & Taylor, 2007).If the random field is not smooth, so that adjacent latticevalues are nearly independent, then the usual Bonferroni boundis very accurate. The purpose of this paper is to bridge thegap between the two, and derive a simple, accurate upper boundfor intermediate mesh sizes. The result uses a new improvedBonferroni-type bound based on discrete local maxima. We givean application to the ‘bubbles’ technique for detectingareas of the face used to discriminate fear from happiness.     

Using a logical model to predict the growth of yeast

Background  

A logical model of the known metabolic processes in S. cerevisiae was constructed from iFF708, an existing Flux Balance Analysis (FBA) model, and augmented with information from the KEGG online pathway database. The use of predicate logic as the knowledge representation for modelling enables an explicit representation of the structure of the metabolic network, and enables logical inference techniques to be used for model identification/improvement.     

Identification of murine natural killer cell subsets with monoclonal antibodies derived from 129 anti-C57BL/6 immune spleen cells

Two hybridomas producing monoclonal antibodies reactive with natural killer cells were selected after fusion of 129 anti-C57BL/6 immune spleen cells with P3X63-Ag8.653 myeloma cells. Treatment of normal or stimulated cells with the 4LO3311 or the 4LO439 mAb and rabbit complement inhibited natural killer and antibody-dependent cellular cytotoxicities, whereas cell lysis mediated by natural cytotoxic cells, cytotoxic T lymphocytes, or activated macrophages was unaffected. Lymphokine-activated killer activity was reduced after complement-mediated treatment of interleukin-2-stimulated spleen cells with the 4LO3311 mAb but not after treatment with the 4LO439 mAb. Similar treatment of spleen cells with either mAb had no effect on the mitogen-induced proliferation of T and B lymphocytes and did not alter the frequency of antibody plaque-forming cells in immune spleen cell suspensions. The 4LO3311 and 4LO439 mAbs thus appear to be specific for NK cells and their progeny. Flow cytometry analysis confirmed that 4LO3311+ and 4LO439+ cells are phenotypically identical to NK-1.1+ cells. The epitope recognized by the 4LO3311 mAb has the same strain distribution as the NK-2.1 alloantigen previously detected with NZB anti-BALB/c antiserum, whereas the 4LO439 mAb appears to identify a new NK cell marker exclusively expressed in mice of C57BL lineage. The relationship of the molecules detected with either the 4LO3311 or the 4LO439 mAb to polymorphic antigens of the Ly series is discussed.