Dry reverse micelles of the anionic twin-tailed surfactant bis(2-ethylhexyl) sulfosuccinate (AOT) dissolved in nonpolar solvents form an organogel when p-chlorophenol is added in a 1:1 AOT:phenol molar ratio. The proposed microstructure of the gel is based on strands of stacked phenols linked to AOT through hydrogen bonding. Small-angle x-ray scattering (SAXS) spectra of the organogels suggest a characteristic length scale for these phenol-AOT strands that is independent of concentration but dependent on the chemical nature of the non-polar solvent used. Correlation lengths determined from the SAXS spectra indicate that the strands self-assemble into fibers. Direct visualization of the gel in its native state is accomplished by using tapping mode atomic force microscopy (AFM). It is shown that these organogels consist of extended fiber bundle assemblies. The SAXS and AFM data reinforce the theory of a molecular architecture consisting of three length scales-AOT/phenolic strands (ca. 2 nm in diameter) that self-assemble into fibers (ca. 10 nm in diameter), which then aggregate into fiber bundles (ca. 20--100 nm in diameter) and form the organogel. Ferrite and cadmium sulfide nanoparticles have been synthesized in AOT reverse micelles, and the preferential incorporation of these ferrite nanoparticles along the organogel fibers is observed via AFM The addition of lecithin (phosphatidylcholine) to AOT water-in-oil microemulsions leads to a dramatic increase in viscosity and the formation of an isotropic rigid bicontinuous mesophase as the water content is increased above a specific threshold. Characterization of this phase transition behavior through electrical conductivity measurements, NMR, and rheology indicates a shift to a percolating aqueous network upon the formation of the rigid mesophase. This rigid mesophase possesses equal volumes of the organic and aqueous phases at the percolation threshold. Small angle neutron scattering experiments show a pronounced peak with a characteristic d-spacing that is a function of the system water content. At elevated temperatures these rigid mesophases undergo a phase transition back to the liquid phase and are thermoreversible in nature. The SANS profiles demonstrate that the rigid mesophases possess a high degree of ordering, and modeling of the SANS data indicate that the rigid mesophases have an ordered bicontinuous microstructure. A novel system that undergoes a phase transition from a liquid to a rigid mesophase upon an increase in temperature also exhibits thermoreversible behavior An exciting extension of this rigid mesophase is the formation of mixed AOT + lecithin reverse micelles (water-in-oil microemulsions) at low concentrations. AOT tends to form spherical reverse micelles spontaneously in solution once above the critical micelle concentration (c.m.c). SANS profiles indicate that as lecithin is added to an AOT water-in-oil microemulsion a deformation of this spherical geometry occurs. Cadmium sulfide nanoparticles were then synthesized in this system in order to observe any differences in particle morphology utilizing transmission electron microscopy (TEM). In typical spherical AOT reverse micelles, the CdS obtained is spherical and relatively monodisperse in terms of size. In an equimolar mix of AOT and lecithin, CdS needles are obtained with aspect ratios ranging from 12--36. It is hypothesized that this change in morphology can be related to the shape of the reverse micelle in which the CdS is synthesized, and may be direct evidence of surfactant templating / acase@tulane.edu

acase@tulane.edu

External genitalia are body appendages specialized for internal fertilization. Although congenital external genitalia malformations represent the second most common birth defect in humans, the genetic pathways governing early external genitalia development as well as urethra formation are poorly understood. Proper development of the embryonic anlage of external genitalia, the genital tubercle (GT), requires coordinated outgrowth of the mesodermally-derived mesenchyme and extension of the endodermal urethra within an ectodermal epithelial capsule. Here we demonstrate that Beta-Catenin plays indispensable and distinct roles in each of the aforementioned three tissue layers. WNT-Beta-Catenin signaling is required in the endodermal urethra to activate and maintain Fgf8 expression and direct GT outgrowth, as well as to maintain homeostasis of the urethra. Moreover, Beta-Catenin is required in the mesenchyme to promote cell proliferation. In contrast, Beta-Catenin is required in the ectoderm to maintain tissue integrity possibly through cell-cell adhesion during GT outgrowth. The fact that both endodermal and ectodermal Beta-Catenin knockout animals develop severe hypospadias raises the possibility that deregulation of any of these functions can contribute to the etiology of congenital external genital defects in humans / acase@tulane.edu

The PowerFuL programming language combines the expressive power of functional and logic programming languages, via the prescriptive use of denotational semantics. PowerFuL's implementation is based upon execution of it's denotational definition but also incorporates 'optimizations,' which are informal notations that represent and manipulate logical variables in a way similar to SLD-resolution We formalize PowerFuL's operational semantics by considering the terms that are produced within the interpreter to be a language, which we call Opts, and providing a denotational semantics for it. The semantics we provide maps Opts into PowerFuL's semantic algebra, so we may consider both PowerFuL code and terms used by PowerFuL's interpreter to represent expressions over the same algebra, denoting elements of the same domain This formalization of the operational semantics (as embodied by the interpreter) gives us a formal understanding of PowerFuL's interpretation and provides a logical characterization of PowerFuL's logical capability. We also provide PowerFuL with an analog to logic programming's computed answer substitution We show that PowerFuL's operational behavior is similar to that of constraint logic programming languages by giving a purely operational characterization of constraint logic programming and comparing it to PowerFuL's operational model. This suggests that PowerFuL can be extended to handle new domains in the same way logic programming languages are extended to form constraint logic programming languages This work is an example of 'reasoning about programs' and programming languages, an avowed goal of a great deal of work, but rarely performed. Our success in analyzing PowerFuL can be attributed to PowerFuL's elegant denotational semantics and wise design considerations. We discuss which aspects of PowerFuL's design were useful to us in formally reasoning about PowerFuL, and argue that this helps determine which design considerations are practical in general / acase@tulane.edu

This dissertation presents an archaeological study of household units and their surrounding built environment at the site of Chunchucmil in the northern Maya lowlands (Yucatan, Mexico). Complementary lines of evidence, the architectural, artifactual, and soil chemical spatial patterning are used at two residential groups of two different Classic Period occupations to elucidate changing patterns of domestic life. Chunchucmil grew to become a sprawling trading city in the middle of the Classic period (A.D. 400-650), while during the Late-Terminal Classic (A.D. 650-1000), after a dramatic depopulation, the site was home to only a few hundred people. This research focuses on the examination of domestic archaeological assemblages, use of space and formation processes in indoor and outdoor domestic areas, social and economic processes, and household dynamics operating in these residential groups during two dramatically different periods A site-level analysis with Geographic Information Systems (GIS) of the settlement layout, internal configuration of residential groups, and other features of the built environment for each period complements this study by elucidating the wider context for the transformations of the settlement and domestic life. By comparing residential groups and the layout of their contemporaneous settlement, I attempt to identify, at the domestic level, socioeconomic and political transformations occurring at the site throughout the Classic period (ca. 300/400-1000/1100 A.D.) The combination of extensive excavations inside buildings, grid testing across the extramural areas of houselots, study of archaeological assemblages considered in their depositional contexts, and geochemical sampling of floors and soils reveals a rich picture of domestic life at two Classic-period residential groups at Chunchucmil, the late Early Classic-early Late Classic Kaab' Group and the Late-Terminal Classic Xnokol Group. Traces of discard practices, ritual and everyday activities, patterns of use of space inside and outside structures, social and economic processes operating at the domestic level, and household dynamics are brought to light by the intersecting lines of evidence / acase@tulane.edu

This dissertation is a critical introduction to Sam Shepard's playwriting career. Chapter One describes the cultural and theatrical milieu of Off-Off-Broadway in the early 1960's and discusses the theoretical foundations and intellectual background for Shepard's dramatic conceptions in the work of five Continental dramatists: Luigi Pirandello, Antonin Artaud, Bertolt Brecht, Eugene Ionesco, and Samuel Beckett; and two American theatre groups: The Living Theatre and The Open Theatre. Chapter Two analyzes five of Shepard's non-realistic plays: Cowboys #2 (1967), Chicago (1966), La Turista (1967), The Tooth of Crime (1972), and Action (1975). Chapter Three examines Shepard's quartet of domestic dramas: Curse of the Starving Class (1976), Buried Child (1978), True West (1981), and Fool For Love (1983) Shepard's four major screen roles in Days of Heaven (1978), Resurrection (1980), Frances (1982), and The Right Stuff (1983), are briefly discussed in an afterword. An appendix contains a chronology of Shepard's career that highlights the major dates in his professional life, catalogues the major productions of his plays, and offers pertinent biographical data. The dissertation founds Shepard's drama in a dramatic tradition and demonstrates an organic development in the plays from metatheatre through personal expressionism, social expressionism, absurdism, and modified realism / acase@tulane.edu

In the first three chapters, we examine situations under which a federal system characterized by decentralized leadership entails an efficient allocation of resources in the presence of interregional spillovers and household attachment. Regional governments, the central government and residents play a three-stage game, in which regional governments are Stackelberg leaders and the center is a common Stackelberg follower. Regional governments decide how much of the public goods they should provide and the center designs an income redistribution policy. Given those policies, residents select their residential location. In chapter 1, we show that the subgame perfect equilibrium for the decentralized leadership game is socially efficient despite the degree of labor mobility provided that regional preferences are quasilinear and the center's preferences over regional welfare levels are strictly convex. In chapter 2, we show that decentralized provision of public goods may be efficient if the center cares about regional welfare levels and views them as complements. The implied allocation is proportionally equitable. In chapter 3, we model transboundary externalities as correlated externalities and abatement technology as coarse. We demonstrate that decentralized control of acid rain may be efficient in the presence of correlated externalities and household attachment if the center views regional welfare levels as complements. When they are substitutes, the allocation is inefficient; it is efficient if externalities are not correlated in the sense that there is no regional pollution damage. In chapter 4, we examine non-cooperative provision of local public goods in an economy characterized by household attachment to regions. We assume that household psychic cost with the migration is a decreasing function of the number of migrants settled in the receiving country. We show that the subgame perfect equilibriums for the decentralized leadership in the presence of imperfectly mobile residents are socially inefficient while the decentralized leadership in the presence of perfectly mobile residents are socially efficient / acase@tulane.edu

acase@tulane.edu

Give a man a fish and he will eat for a day. Teach him how to fish and he will eat forever. Author Unknown Users of current text-based computer interfaces do entirely too much typing and too much searching. The computer should alleviate more of the burden of being so specific. Automation is the key but automation in this domain is challenging. In order to allow users to incorporate more automation into their interfaces, we find that a new command shell architecture is needed. Our approach is to centralize knowledge in a persistent way while parallelizing execution. The working prototype, Fish, maintains a global, persistent knowledge repository across concurrent interactive sessions. Fish is customizable and extensible, with not only a concise command language but also a full programming language. It supports efficient communication between the machine and the user in many ways, most notably by giving the user access to the results of previously executed commands / acase@tulane.edu

A multidisciplinary approach is developed and demonstrated for exploiting knowledge about structure for the purpose of extracting information from noisy textual data. This approach combines the active database paradigm, database organization and clustering of records, fuzzy parsing, fuzzy retrieval, an aggregation algebra, and measures of both performance and accuracy. Fuzzy retrieval, in the form of set and fuzzy operators, is accomplished by considering each symbol of the input text to be imperfect and retrieving non-exact matching records from the database that hold for a particular threshold value. The set of low-level database operators constrain the cardinality and accuracy of retrievals. A hierarchical method of clustering the database is defined, whereby the records are partitioned in a manner such that similar records are in the same cluster. This clustering strategy is guaranteed to be mutually exclusive and a complete cover of the data records. Associated with these clusters is an algebra that combines clusters of data into one window of ranked data. A set of fuzzy measures are defined that are used to aggregate and rank sets of records / acase@tulane.edu