Distortions that affect macroeconomic outcomes are an important avenue through which we can explain differences in cross country output and productivity. In this thesis I concentrate on two types of distortions, political economy and informational distortions. In Chapter one, I build a model of intermediated corruption where interactions between government bureaucrats and those who bribe them are mediated by a third party. I show that intermediation has significant effects on the incidence of corruption and the prices entrepreneurs pay for permits. When corruption is particularly acute, measures that increase the frequency with which government bureaucrats are audited often have the undesirable result of increasing the prevalence of corruption because of intermediation. In Chapter two I explore the link between corruption and inequality by building a model in which tax collectors are corrupt. I find that as inequality increases, the frequency of corrupt transactions increases as well. I also find that where corruption is more severe, because wealthier individuals tend to pay lower taxes, inequality is higher. I perform a few quantitative experiments to better understand this linkage. Chapter three explores distortions that are caused by adverse selection in markets with search frictions. I find that when participants are concerned about the information they reveal through their interactions in the market, the distortions to liquidity are deeper and that equilibrium selection is significantly affected. I also find that markets with reputational concerns are more sensitive to outside shocks.

Distortions that affect macroeconomic outcomes are an important avenue through which we can explain differences in cross country output and productivity. In this thesis I concentrate on two types of distortions, political economy and informational distortions. In Chapter one, I build a model of intermediated corruption where interactions between government bureaucrats and those who bribe them are mediated by a third party. I show that intermediation has significant effects on the incidence of corruption and the prices entrepreneurs pay for permits. When corruption is particularly acute, measures that increase the frequency with which government bureaucrats are audited often have the undesirable result of increasing the prevalence of corruption because of intermediation. In Chapter two I explore the link between corruption and inequality by building a model in which tax collectors are corrupt. I find that as inequality increases, the frequency of corrupt transactions increases as well. I also find that where corruption is more severe, because wealthier individuals tend to pay lower taxes, inequality is higher. I perform a few quantitative experiments to better understand this linkage. Chapter three explores distortions that are caused by adverse selection in markets with search frictions. I find that when participants are concerned about the information they reveal through their interactions in the market, the distortions to liquidity are deeper and that equilibrium selection is significantly affected. I also find that markets with reputational concerns are more sensitive to outside shocks.

In this thesis several classes of directed paths are considered as models of linear polymers in a dilute solution. We obtain the generating functions for each model by considering factorization arguments. Information about the polymer behaviour can be extracted from the singularity structure of the associated generating functions. By using modified versions of these models we study the adsorption and localization of polymer molecules, the behaviour of polymers subject to a tensile force, the effects of stiffness, as well as the behaviour of polymers in confined geometries. In each of these situations the resulting generating functions contain at least two physical singularities. We identify the phase transitions in these systems by a changeover in the dominant singularity of the generating function. In the study of localization and polymers subject to a force, we utilize both homopolymer and random copolymer models. For copolymers, the physically relevant properties are obtained by considering a quenched average of the free energy over all possible monomer sequences. This procedure is intractable even for the simplest models. By considering the Morita approximation for several walk models we obtain results which give a bound on the corresponding features of the quenched system. We use a mapping between a simple model of duplex DNA and an adsorbing Motzkin path in order to study the mechanical unzipping of duplex DNA. From this model, we obtain force-temperature diagrams which show re-entrant behaviour of the force. We also develop a simple low temperature theory to describe the behaviour of the force close to T=0 and find that the shape of the force-temperature curve is associated with entropy in the ground state of the system. We consider the effect of stiffness on polymer adsorption and find that the phase transition is second order for all finite stiffness parameters. For systems of polymers in confined geometries, we find that the behaviour of the polymer depends on the distance between the confining surfaces and the associated interactions with each surface. In this problem, there exist regimes where the polymer exerts a force on the surfaces which can be attractive, repulsive or zero.

Glutathione transferases (GSTs) are good candidates for investigations of enzyme evolution, due to their broad substrate specificities and structural homology. The primary role of GSTs is to act as phase II detoxifying enzymes protecting the cell from toxic compounds of both endo- and exogenous origins. The detoxification is conducted via conjugation with glutathione (GSH), which facilitates their removal from the body. The work presented in this thesis has supported a theory for enzyme evolution when the multiple pathway to novel functions can been seen to involve a “generalist” state from which “specialist” states with a new activities can evolve. The generalist has broader specificity and lower activity than the specialist. The term quasi-species is used for a group or cluster of enzyme variants with similar functional properties, and this entity has been suggested as the fittest group for further evolution. This is based on studies of the evolution of new GST variants in two generation. Three diverging clusters or quasi-species, with diverging substrate selectivity, were identified from a GST M1/M2 library, by using directed evolution (family DNA shuffling), multiple substrate screening and multivariate statistics as tools. One of the clusters was M1-like and the other was M2-like, both functionally and structurally. The third quasi-species diverged orthogonally from the parent-like distributions. Its functional character can be referred to as a “generalist” as it had lower activities with most of the substrates assayed except for epoxy-3-(4-nitrophenoxy)-propane (EPNP) and p-nitrophenyl acetate (pNPA). Another round of family DNA shuffling was made with selected variants from the “generalist” quasi-species. From the second generation three quasi-species emerged with diverging functions and sequences. The major cluster contained enzyme variants that represented a direct propagation of the generalists. Diverging from the generalists was a cluster with high specificity with isothiocyanates (ITCs). Increased ITC specificity and decreased epoxide specificity was observed among the novel variants (specialists). The change in functional properties was attributed to a Tyr116His substitution in the active site. These results demonstrate the usefulness of multivariate analysis in the quest for novel enzyme quasi-species in a multi-substrate space, and how minimal changes in the active site can generate distinctive functional properties. An application of our method could be identification of enzyme quasi-species that have lost their sensitivity with alternative inhibitors.

Thesis (PhD)--University of South Australia, 2002.

An emergent qualitative design provided the scaffolding for the micro-analysis of video footage and subsequent video-cued discussion with four reviewers. The collated material was used to prepare thick descriptions which were annotated for infant and therapist behaviours. A further thematic analysis of these behaviours provided 14 sets of behaviours used by the medically fragile newborn infants to indicate availability for interplay and 20 sets of behaviours used by the therapist in response to the infant. The interaction of these categorised behaviours provided seven markers of interplay between the music therapist and the medically fragile newborn infant.

The purpose of the research was to form a defensible basis for considering possible changes in classroom practice within a small rural state school, and it involved four, mixed-ability classes comprising Year 9 and 10 students. These classes were taught an energy-related module by the researcher. In the preliminary phase, which involved two classes, resources were developed to produce a more student-centred module. These resources, and the constructivist approach which informed their development, are described. In the subsequent comparative phase, the reformed module was taught using two contrasting strategies - one teacher-directed and the other, student-managed. During this phase individual achievement and group investigative skills were assessed. Student perceptions of classroom environment were probed using an existing instrument, the ICEQ. The range of classroom activity and level of student engagement was continuously monitored by independent observers using a specifically developed instrument, termed the SALTA.No overall learning advantage was demonstrated to either teaching strategy. A small strategy advantage favouring Year 10 students in the student-managed strategy was offset by a similar disadvantage to the Year 9 cohort. A cohort penalty was found to apply to Year 9 students under either strategy, with a paradox in its application. The role of the teacher was found to change significantly under each strategy, with a consistent hierarchy of student engagement with activity emerging. Boys were found to have significantly higher levels of engagement than girls under either teaching strategy. However, this was associated with only modest advantages in achievement. The relationship between engagement and achievement was stronger and more positive under the student-managed strategy. Mismatches between preferred and actual classroom environment were found, ++ / particularly in the dimension of independence. This mismatch was less in the student-managed setting. Increased potential for learning was noted under each strategy.

Dissertation (Ph.D.) -- University of Texas Southwestern Medical Center at Dallas, 2008. / Vita. Bibliography: p. 117-123.

Thesis (B.A.)--Haverford College, Dept. of Computer Science, 2004. / Includes bibliographical references.

Thesis (D. Min.)--Bethel Seminary, St. Paul, MN, 2001. / Abstract. Includes bibliographical references (leaves 248-259).