Geographic Information Systems (GIS) must be able to handle uncertain spatial data. Object oriented databases (OODB) are a good fit for spatial databases. Fuzziness and uncertainty can be implemented in an OODB. By taking the concept of the object oriented database, supporting fuzziness and uncertainty in the model, and incorporating spatial data into the framework, we are providing GIS researchers with what they need: a framework to handle uncertain spatial data, as implemented in the object oriented data model The most important part of this research is how the spatial data is integrated into the fuzzy OODB. This research will show that spatial data is inherently fuzzy and uncertain; that OODB are a much better than relational databases in supporting spatial data; and that by incorporating spatial data into the fuzzy OODB model, we are creating a robust framework for GIS / acase@tulane.edu

The primate pulvinar is connected with several visual areas and is implicated in visual attention and in control of eye movements. Traditionally, the pulvinar has been divided into three broad zones: medial (PM), lateral (PL), and inferior pulvinar (PI). This division was based on cytoarchitecture and the location of prominent fiber bundles and did not correlate to connectional data. Recent studies using various modern neurochemical methods suggest a pattern of organization more consistent with the topography of connections with different visual areas. In monkeys, the ventral pulvinar, consisting of traditional PI and the ventral portion of traditional PL, constitutes a histochemically distinct area termed the inferior pulvinar (PI) complex. The PI complex in monkeys consists of 5, separate zones: the posterior, medial, central, lateral, and the lateral-shell (PIP, PIM, PIC, PIL, and PI L-S) subdivisions, each distinguished by several neurochemical stains There is evidence that the visual system is not spared in neurodegenerative diseases such as Alzheimer's Disease (AD). While AD usually affects memory and attention early in the course of the disease, studies have shown that AD can also affect the visual cortex and visual pathways, including subcortical visual centers. Disruption of functions mediated by the pulvinar may contribute to visual deficits seen in patients with AD. The goal of this study was to investigate the neurochemical organization of the pulvinar and to understand it's role in visuospatial function of non-human primates and humans with or without Alzheimer's Disease, and how certain symptoms of Alzheimer's disease can be related to pathology within this structure We obtained postmortem chimpanzee (Pan troglodytes; n = 8) brains and human brains with no known neurological pathology (n = 5), and brains of patients clinically diagnosed with AD (n = 9). Using cytochrome oxidase (CO) and acetylcholinesterase (AChE) histochemistry, and immunocytochemistry for calbindin D28k, we were able to identify 5 histochernical zones in the chimpanzee PI complex, and 4 zones in the human PI complex. Thioflavin S histochemistry was employed to identify amyloid plaque distribution. Dense plaques were irregularly distributed across the PI complex with a slight trend for PIC having the greatest accumulation / acase@tulane.edu

acase@tulane.edu

Atrial natriuretic peptide (ANP) is a vasoactive peptide hormone generated in the atrium of the heart and released in the circulation. ANP exhibits important functions in blood pressure and volume homeostasis, cardiac hypertrophy, and inhibition of cell proliferation. The binding of ANP to the cell surface guanylyl cyclase-A/natriuretic peptide receptor-A (GC-A/NPRA) activates its intrinsic guanylyl cyclase domain, causing production of the intracellular second messenger cGMP, and subsequently activating cGMP-dependent protein kinase (PKG). Although ANP is known to inhibit cell proliferation and promote apoptosis in numerous cell types, the signaling pathways responsible for the antimitogenic actions of ANP are not well understood. The objective of this study was to elucidate the role of the ANP-NPRA-PKG system in the inhibition of mitogen-activated protein kinases (MAPKs) and in cell growth and proliferation by studying effect of ANP on the activation of MAPKs and the downstream transcription factors cAMP response element binding protein (CREB) and activating protein-1 (AP-1) regulated by MAPKs. These studies have shown the role of the ANP-NPRA signaling system in regulating and inhibiting the proliferation of two types of cells: mouse mesangial cells (MMCs) and Leydig tumor cells (LEDs). We have delineated a pathway for this signaling system, demonstrating that ANP inhibits the activation of MAPKs and two specific proliferation-stimulating transcription factors downstream, CREB and AP-1, effects that were seen to be dependent on PKG and mediated through NPRA rather than through NPRC. These findings help to advance our understanding of the biochemical pathways through which ANP inhibits cell proliferation / acase@tulane.edu

Studies have suggested sex differences in the neural response to drugs of abuse. Previous studies have shown that morphine induces immediate early gene (IEG) expression in the brain and this is reduced by administration of the N-methyl-D-aspartate receptor antagonist, dizocilpine maleate (MK-801). This study looked at the role played by glutamate in morphine-induced IEG expression in the brain and determined if this IEG induction is sexually dimorphic. These experiments also tested if gonadal hormones modulate glutamate receptors and alter behavioral and IEG responses to morphine and MK-801 In this dissertation, the following findings are reported. Morphine induced c-Fos expression in the dorsomedial caudate-putamen (CPu) and in the midline-intralaminar nuclei of the thalamus. Morphine caused a significantly greater expression of c-Fos in the CPu in intact males than in females, and castration with or without hormone-replacement did not eliminate this sex difference. MK-801 inhibited the morphine-induced IEG expression in the CPu in a sexually dimorphic manner, and this sex difference was eliminated by castration of males and restored by administration of gonadal steroids. Ovariectomy with or without estrogen replacement did not alter the ability of MK-801 to completely block the morphine-induced IEG expression in the CPu. MK-801 alone caused a robust induction of c-Fos in the midline-intralaminar thalamic nuclei in females as opposed to a negligible induction in males and this sex difference was independent of gonadal steroids. Significant behavioral sex differences were also seen in response to MK-801, with females showing far greater hyperactivity as compared to males; gonadal hormones did not appear to influence these behavioral responses. Ovariectomy decreased immunoreactivity of the GluR2 subunit of the AMPA receptor in the striatum, whereas no changes were seen in immunoreactivity of the NR1 subunit of the NMDA receptor These results suggest that the responses to both morphine and NMDA receptor antagonists differ between the sexes and emphasize that glutamate is involved in morphine-induced immediate early gene expression in the brain. These findings indicate that sex differences in response to morphine and MK-801 may be mediated by sex-steroid dependent and independent mechanisms and thus have important implications in treatment outcomes of drug addiction / acase@tulane.edu

The division process is not only the most complex but also the most time-consuming arithmetic operation in a digital computer. There exist many types of special-purpose systems which require rapid and repeated division by a set of known constant divisors. Even in general purpose machines, since integer division takes significantly longer than additions or subtraction, if many divisions are needed, this disparity in execution time can result in a bottleneck. It is therefore beneficial to seek ways to do specific division cases faster, in order to improve the average performance of division Numerous solutions have been proposed in response to the deficiencies of the conventional division algorithms, for applications which involve repeated divisions by known constants. The approaches in the literature are outlined and characterized with respect to timing, generality, implied redundancy, and the possibility of shared computation, parallelism,, and pipelined implementation. The application-dependent development of the constant division approaches has left a gap in the theoretical foundations of the algorithms. Here the various methods are mathematically explained and unified through the establishment of their common theoretical basis A major intended contribution of this research is the definition of approaches to division by constants belonging to the set of integers of the form 2$\sp{n}\ \pm$ 1. Generalized algorithms for division by integers of the form 2$\sp{n}\ \pm$ 1, for an arbitrary value or values of $n$, are developed and proved correct. Implementation issues are explored in the development of design suggestions for the constant division method The algorithms presented are a good solution to the problem of division by constants of the specific form 2$\sp{n}\ \pm$ 1, for $n$ $\in$ N, $n$ $>$ 0. The consideration of such a subset of divisor values (of the form 2$\sp{n}\ \pm$ 1) is not, however, a satisfactory solution to the general problem of constant division. Dividers designed for constant divisors in this set can trivially be extended to cover divisors of the form 2$\sp{m}(2\sp{n}\pm1)$, $m$ $\in$ N. The Euler-Fermat theorem is used to show that, with one additional multiplication, division by any integer can be converted to a division by an integer of the for 2$\sp{n}$ $-$ 1. The multiplier to be determined is established to be the value in one period of the reciprocal of the divisor. Approaches to reciprocal determination are therefore presented, specifically methods that take advantage of the special characteristics of reciprocals of integers / acase@tulane.edu

acase@tulane.edu

acase@tulane.edu

acase@tulane.edu

acase@tulane.edu