Shannon L. Fitzpatrick

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The strong isometric dimension of a reflexive graph is related to its injective hull: both deal with embedding reflexive graphs in the strong product of paths. We give several upper and lower bounds for the strong isometric dimension of general graphs; the exact strong isomet-ric dimension for cycles and hypercubes; and the isometric dimension for trees is(More)
During the development of preovulatory follicles, tonic levels of FSH (and steroid) induce expression of aromatase, the LH receptor, and RII beta in a coordinate manner. Despite the similar temporal increase in steady-state levels of mRNA encoding these proteins, the cis-acting DNA elements and trans-acting factors regulating each gene are distinct(More)
Aromatase (CYP19) mRNA is induced by follicle-stimulating hormone (FSH) in granulosa cells of preovulatory follicles and subsequently is rapidly diminished as a consequence of the luteinizing hormone (LH) surge. Primary cultures of rat granulosa cells were used to identify some of the cellular mechanisms by which FSH increases and LH decreases steady-state(More)
Aromatase cytochrome P450 is regulated in granulosa cells of ovarian follicles by the synergistic action of FSH and steroids. The effect of FSH can be mimicked by forskolin suggesting that transcription of the aromatase gene is regulated by cAMP. In contrast, aromatase is constitutively expressed in the rat R2C Leydig cells. To characterize the functional(More)
In cellular networks, channels must be assigned to call requests so that interference constraints are respected and bandwidth is minimized. The number of call requests per cell is continually changing, making channel assignment naturally an online problem. We describe two new online channel assignment algorithms for networks based on a regular hexagonal(More)
A method to generate lower bounds for the channel assignment problem is given. The method is based on the reduction of the channel assignment problem to a problem of covering the demand in a cellular network by pre-assigned blocks of cells, called tiles. This tile cover approach is applied to networks with a cosite constraint and two different constraints(More)
In the firefighting and the graph searching problems, a contaminate spreads relatively quickly. We introduce a new model, on directed acyclic graphs, in which the contamination spreads slowly. The model was inspired by the efforts to stem the lava flow from the Eldfell volcano in * Partially supported by grants from NSERC. Iceland. The contamination starts(More)