The main subject of this thesis is the study of electronic and magnetic properties of materials containing 3d transition metal atoms. Our motivation stems mainly from the modern fields of spintronic computing and solar energy conversion. The two primary goals of this work are to determine (i) why certain transition metal impurities in certain semiconductors can induce magnetic properties suitable for spintronic computing applications, and (ii) how transition metal impurities can be used to modify the electronic band gaps of semiconductors and insulators in ways useful for harnessing solar energy and for other applications. To accomplish these goals, we have applied both experimental and theoretical tools. We studied high quality materials prepared by advanced synthesis techniques using x-ray spectroscopy methods at synchrotron light sources. The results of these experiments were interpreted using a variety of theoretical techniques, primarily using computational software developed as part of this thesis and discussed herein. Regarding the study of introducing transition metal impurities into semiconductors to induce magnetic properties, we first developed and demonstrated a method to determine the location of impurity atoms within the host semiconductor lattice. This allowed to us explain the presence and absence of ferromagnetism in samples prepared under only slightly different synthesis conditions, which helped to address some long--standing issues in the spintronics field. We then studied an advanced and promising material -- indium (III) oxide with iron impurities -- to determine how magnetic ordering was maintained up to room temperatures. Our techniques unveiled that a portion of the iron atoms were coupled to oxygen vacancies in the material to create conditions which propelled the observed magnetism. This finding confirmed some earlier theoretical predictions by others in the field. For the study of electronic band gap modifications in semiconductors and insulators via the incorporation of transition metal atoms, we investigated a wide range of materials synthesized using different techniques. Again, we used experimental techniques to determine the location of impurity atoms within the materials, and used this to understand how band gaps were modified upon the introduction of the impurities. For Ti implantation into SiO2, Ni substitution into ZnO, and a new material, MnNCN, we have determined the electronic band gaps and used our techniques to explain how the values for the gaps arise. Finally, an additional outcome of this thesis work is a software program capable of simulating x-ray spectra using various advanced quantum models. We rewrote and built upon powerful existing programs and applied the result to the above studies. Our software was further applied in a collaborative effort with other researchers at the Canadian Light Source to study the differences in two experimental techniques for measuring x-ray absorption: partial and inverse partial fluorescence yields. By using the proper absorption and scattering formalisms to simulate each technique, we were able to explain the differences between the experimental spectra obtained from each. We explain fluorescence yield deviations using an analysis based on the spin configuration of different states, suggesting that the technique can be further extended as a quantitative spin state probe. These results could have significant implications for the field of soft x-ray absorption spectroscopy.

In contemporary philosophy of mind, the issue of consciousness has taken center stage. Broadly speaking, those who deal with consciousness fall into two camps: those who prioritize empirical work and those who favor conceptual investigation. One prominent argument has served to deepen the divide: the argument for the possibility of zombies. In this paper I intend to examine closely this argument, as it’s presented by David Chalmers, and some of the attempts to discredit it. In so doing, I present some of my own arguments against it, as well as the claim that if it’s sound, then materialism is false. Finally, I present a sketch of a new way of thinking about consciousness that would, I argue, guard against the threat—real or merely apparent—of arguments such as the zombie-argument.

Calcium and calmodulin are implicated in mediating the Ca2+-dependent regulation of gap junctions that are essential for the intercellular transmission of molecules such as nutrients, metabolites, metal ions and signal messengers (< 1000 Da) through its specialized cell membrane channels and communication to extracellular environment. To understand the key determinants for calcium and calmodulin regulation of gap junction, in this study, we identified a calmodulin binding domain in the second half of the intracellular loop of Cxonnexin50 (the major gap junction protein found in an eye lens) using peptide fragments that encompass predicted CaM binding sites and various biophysical methods. Our study provides the first direct evidence that CaM binds to a specific region of the ubiquitous gap junction protein Cx50 in a Ca2+-dependent manner. Furthermore, two novel CaM binding regions in cytosolic loop and C-termini of Connexin43 (the most ubiquitous connexin) have been shown to interact with CaM with different binding modes in the presence of Ca2+ using high resolution NMR. Our results also elucidate the molecular determinants of regulation of gap junction by multiple CaM targeting regions and provide insight into the molecular basis of gap junction gating mechanism and the binding of CaM to the cytoslic region Cx43-3p as the major regulation site. Upon response to the cytosolic calcium increase, CaM binds to the cytosolic loop to result in the conformational change of gap junction and close the channel. It is possible for CaM to use an adjacent region as an anchor close to the regulation site to allow for fast response. Since a large number of residues in the Cxs mutated in human diseases reside at the highly identified CaM binding sites in Cxs, our studies provide insights into define the critical cellular changes and molecular mechanisms contributing to human disease pathogenesis as part of an integrated molecular model for the calcium regulation of GJs. In addition, we have applied the grafting approach to probe the metal binding capability of predicted EF-hand motifs within the streptococcal hemoprotein receptor (Shr) of Streptococcus pyrogenes as well as the nonstructural protein 1 (nsP1) of Sindbis virus and Poxvirus. This fast and robust method allows us to analyze putative EF-hand proteins at genome-wide scale and to further visualize the evolutionary scenario of the EF-hand protein family. Further, mass spectrometry has also been applied to probe modification of proteins such as CaM labeling by florescence dye and 7E15 by PEG.

Racial equality in the United States educational system has long been and continues to be a source of debate. Specifically, the disparities between whites and other minority groups have been increasingly more critical. Blacks and Latinos consistently score lower than whites on standardized tests and academic course work. There have been several explanations given for poorer school performance by certain minority groups than whites. In this dissertation, I explore the black white achievement gap through the examination of one widely known explanation, oppositional culture theory. This research investigates the major tenets of oppositional culture theory and the contemporary multicultural navigator concept. Using a grounded theory method of analysis, I examine the connections between suppositions of the theory and black students in the Upward Bound academic achievement program.

In cultural adaptation, the translator has a solid theoretical ground to stand upon; scholars have elaborated strategies that are helpful to this effect. However, there is little research, if any, to rely upon in the matter of temporal adaptation. The aim of this paper is to fill this gap. The primary data used in this translational study consists of an English source text that was published in 2008 and the resulting target text, translated to Swedish in 2012. Hence, in order for the target text to function in its time, there was a four-year long time gap to fill with accurate and relevant data and in a style that would not deviate from the author’s original intentions; the target text needed to be temporally adapted. In what follows, I will suggest a set of strategies for temporal adaptation. The model is elaborated with strategies for cultural adaptation as a starting point and based upon measures taken to relocate the target text to 2012. The suggested strategies are time bridging, updating, adjustment and omission. These four strategies make up the model that I put forward to bridge the theoretical gap that seems to prevail in the matter of temporal adaptation. However, considering that the data used in this study was relatively limited, the applicability of the strategies may be the scope of future studies.

This thesis presents the design of a two-dimensional phononic band gap crystal simulator, and phononic crystal analysis. <br /><br /> Phononic crystals and their application to microwave acoustic filters are studied. Wave mechanics is introduced. A two-dimensional phononic crystal simulator is developed. Simulator operation is validated through comparison with published data. Design parameters for phononic crystal band gap engineering are outlined. Digital signal processing and wave mechanics are utilized to analyze fractal and circular inclusion based phononic crystals. Topics for further study are given. <br /><br /> Phononic crystal band structure is found to be sensitive to inclusion boundary geometry. Fractal inclusion based crystals provide multiple pass band characteristics. The evolution of a fractal inclusion in a phononic crystal may cause band gap widening and the formation of new band gaps. Circular inclusion based phononic crystals have piecewise-linear phase characteristics and quality factors up to 600.

Modern roundabouts are increasingly being considered as a preferred intersection design within urban street networks in North America due, in large part, to the increased safety provided by roundabout. In the last decade, much research has been conducted in North America to quantify the performance of roundabouts in terms of vehicle delay as a function of vehicle traffic volume and roundabout geometry. In most jurisdictions, vehicles entering and existing the roundabout are required by law to yield right-of-way to pedestrians crossing the roundabout approach, and consequently, the presence of substantial pedestrian volumes are expected to degrade operational performance of the roundabout for vehicles. However, very little research has been conducted to estimate the impact that pedestrian volumes have on average vehicle delay. The aim of this research is to study the effects of pedestrian volume, entry traffic volume, and conflicting or circulating volume, on the delays that vehicles experience when traversing the roundabout. An analytical model is proposed to estimate vehicle delays on the basis of traffic flow and queuing theory. The model is applicable to single lane roundabouts. The model was calibrated and validated using vehicle delays obtained from the micro-simulation software, VISSIM (version 5.2) for a range of different conditions. The research described in this thesis demonstrates that pedestrian flows cause delays to vehicles traversing the roundabout in four distinct ways. Existing analytical techniques included within most design manuals consider only one of these sources of delays and consequently, conventional models typically under-estimate the impact that pedestrian flows have in terms of increasing delays to vehicles traversing the roundabout.

Upon activation by the platelet-derived growth factor receptor (PDGFR), phosphatidylinositol 3'-kinase (PI3K) converts phosphatidylinositol 4,5-bisphosphate to phosphatidylinositol 3,4,5-trisphosphate to activate the PI3K/Akt cellular survival signalling pathway within cells. The p85 subunit of PI3K has also been shown to have GTPase activating protein (GAP) activity towards Rab proteins involved in receptor endocytosis and trafficking, specifically Rab5 and Rab4. Rab5 is responsible for regulating the fusion of vesicles containing activated receptors to traffic them to intracellular early/sorting endosomes. Rab4 is responsible for regulating the exit of receptors to a recycling pathway back to the plasma membrane. The p85 RabGAP activity is responsible for deactivating Rab5 and Rab4 function by accelerating their GTPase activity, resulting in the inactive conformation of Rab5 and Rab4, and decreased vesicle fusion events during receptor trafficking. The work in this thesis was performed to understand how p85 interacts with, and regulates, Rab5 and Rab4. Glutathione S-transferase pulldown experiments showed the p85 protein was able to interact with Rab5 through its BH domain and another unidentified domain. Cells expressing a p85-R274A mutant defective for RabGAP activity displayed increased PDGFR activation and decreased degradation. To understand the mechanism of decreased PDGFR degradation, PDGFR immunoprecipitation experiments showed the PDGFR was ubiquitinated, a signal needed for multi-vesicular body sorting. Biotinylation experiments showed the PDGFR was being more rapidly endocytosed and then sequestered within the cell. Immunofluorescence experiments showed cells expressing the p85-R274A mutant clearly altered PDGFR trafficking during receptor endocytosis. These results suggest the PDGFR was not spending longer periods of time on the cell surface to continue signalling and was not lacking the modification needed to be sorted to a degradative pathway. The defective trafficking observed in p85-R274A expressing cells, over time, may block PDGFR trafficking, which prevents normal PDGFR dephosphorylation and degradation, and could be attributed to a lack of sufficient cytosolic Rab5-GDP and Rab4-GDP required to associate with new membranes and facilitate additional vesicle fusion events. The lack of lysosomal targeting allows the receptor to be sequestered in cells, but still have the ability to signal as the receptor would not be targeted to multi-vesicular bodies where signalling is abolished.

Tropical rainforests are among the most complex and diverse ecosystems, composed of a mosaic of shady understory under the closed canopy and tree-fall gaps of varying sizes and age. The light reaching the forest floor favors the recruitment of fast growing plant species and provide food resources for other animal species including butterflies. The Nymphalidae are the most species rich butterfly family in the tropics, and are ideal bioindicators. We investigated the effect of the tree-fall gaps on the assemblages of fruit feeding Nymphalidae. We used fruit-bait traps in 15 tree-fall gaps from 100 to 1000 m2 and 15 in undisturbed understory, from July until November, in a lowland tropical rainforest in southeastern Peru. We found distinct differences in butterfly assemblages between tree-fall gaps and understory, with a higher number of species in gaps, associated with a higher level light. We identified several species mostly found in one of the habitats, and generalist species. The heterogeneity was large within the same site both in gaps and in the understory. The difference between butterfly assemblages increased with gap size. Butterfly species were mainly associated with the absence of vines in the gaps, and found in large and light gaps. We distinguished several species according to their preferences for the vegetation structure, light level and size of gaps. We concluded that one example that maintains the biodiversity in the tropical rainforest is the formation of tree fall gaps of different sizes resulting in different species assemblages.

<p>This dissertation consists of two separate essays on economics of education. First, the role of teacher-student interactions is analyzed. Teacher effectiveness is generally characterized by a single effect that is common across students. However, educators are multi-task agents that choose how to allocate their efforts among pupils. Some teachers may target their courses towards the top students in the class while others to the bottom, leading to different complementarity effects. Moreover, the introduction of accountability programs, such as No Child Left Behind (NCLB), could induce a reallocation of teacher's efforts, affecting the dynamics of student-teacher interactions. This study shows that the role of complementarities is key from a policy perspective. In this regard, an analytical framework and a novel iterative algorithm are implemented in order to characterize and quantify these effects. Results indicate that interaction effects played a crucial role in shaping the distribution of student achievement, especially after the implementation of NCLB. While more than half of the total gains in test scores experienced by the bottom third of the student achievement distribution post NCLB are due to adjustments in teacher-student complementarities, those with the very highest abilities have seen decreases in their performance.</p><p>In the second essay, gender disparities in educational attainment are explored across races. The sizable gender gap in college enrollment, especially among African Americans, constitutes a puzzling empirical regularity that may have serious consequences on marriage markets, male labor force participation and the diversity of college campuses. For instance, only 35.7 percent of all African American undergraduate students were men in 2004. Results show that, while family background characteristics cannot account for the observed gap, proxy measures for non-cognitive skills are crucial to explain it.</p> / Dissertation