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This dissertation consists of two chapters studying the importance of household income for shaping student outcomes in the market for higher education in the United States. The first chapter uses the High School Longitudinal Study of 2009 to document that conditional on student ability, high-income students are more likely to enroll in college and are more likely to attend a highly selective college conditional on enrolling. These gaps are mostly explained by differences in application rates and in enrollment rates conditional on being admitted, rather than differences in admission rates. While students generally prefer to attend the most selective college they are accepted to, low-income students are less likely to attend their preferred college due to costs. These findings suggest that financial aid provided by colleges is generally insufficient in closing enrollment gaps, and that the observed application gaps may be rational: low-income students will choose not to apply if doing so is costly and they do not expect to receive sufficient aid if admitted. Motivated by the empirical findings of the first chapter, the second chapter builds and estimates an equilibrium model of the U.S. college market featuring tuition discrimination and a decentralized admissions system. Students who differ in their financial resources and innate ability apply to a subset of colleges and are uncertain about their prospective admissions and financial aid. Colleges observe a noisy signal of student ability and compete by choosing admissions standards and tuition schedules. According to the estimated model, differences in application rates between high- and low-income students, conditional on ability, are due to student expectations over admissions and financial aid, which are consistent with college policies in equilibrium. Low-income students receive generous financial aid at selective colleges because only the highest-ability among them apply, making their signals highly informative. If signals became less informative (e.g., colleges stopped using the SAT), all high-ability students would be worse off and only high-income, low-ability students would modestly benefit. Finally, the model suggests that increasing federal need-based financial aid greatly benefits low-income, high-ability students by alleviating credit constraints. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]

Orthohantaviruses are a genus of Bunyaviruses carried by a range of rodent hosts. They are found in endemic foci across the globe and are associated with the zoonotic diseases haemorrhagic fever with renal syndrome and hantavirus cardiopulmonary syndrome. Orthohantaviruses are enzootic to south-eastern, central and northern parts of continental Europe. The virus has historically been considered absent from the British Isles, but the endemic presence of Seoul orthohantavirus (SEOV) was demonstrated in wild and pet rats in the UK in 2012. For the last six years several human cases of orthohantavirus-infections have been diagnosed in the UK with associated acute renal failure. Currently, treatment for haemorrhagic fever with renal syndrome and hantavirus cardiopulmonary syndrome is purely symptomatic. The mechanisms underlying the pathogenesis of orthohantavirus infections are not fully understood though several lines of enquiry have demonstrated the multifaceted nature of the disease, with direct virally mediated mechanisms, indirect immune mediate mechanism and genetic host factors all likely contributors to the clinical picture. Clinical proteomics is a field of study in which high-throughput analytical approaches are used to investigate proteins in clinical samples. A major advantage of the proteomic approach is that no a priori knowledge is required for proteome analysis, making it an excellent hypothesis generating experimental method. The high-throughput facets of proteomic methods also make the approach very useful for infections such as orthohantavirus, for which aspects of its pathology remains unclear, and the relative rarity of the associated diseases result in limited access to biological samples. The aims of this study were to use label-free proteomics to discover biomarkers of orthohantavirus infection in clinical human sera and to study the cellular interactome of recombinant SEOV Cherwell glycoproteins in a human kidney cell line, with the objective of gaining further insights into mechanism involved in the processing of viral proteins through host cells. A pipeline for investigating the human serum proteome during diseased and healthy conditions was established. Using label-free proteomics in association with immunological methods, afamin and galectin 3-binding protein were identified and evaluated as putative biomarkers of orthohantavirus infection. Both proteins showed promise as factors involved in the response to acute Seoul orthohantavirus infection. Their relevance as markers of disease were supported by their functional annotation, with afamin playing a possible role in the cellular response to oxidative stress, and galectin 3-binding protein being associated with pro-inflammatory and pro-coagulant activity. Further validation studies with larger sample cohorts are warranted. Initial investigations into the in vitro interactome of recombinant SEOV Cherwell glycoproteins identified 12 potential associations between host and viral proteins. While functional analysis of selected proteins revealed a potential for relevance in the viral life cycle, further follow-up of these findings will be required to establish whether the identified associations are firstly, true associations, and secondly, biologically relevant interactions.

A model for the flow around bluff bodies has been developed. It is applied to an investigation of parachute canopy aerodynamic characteristics. Since the model assumes an axisymmetric incompressible high Reynolds number flow, it is only applicable to the calculation of aerodynamic characteristics at zero angle of attack. The flow is assumed to separate from the canopy at its surface discontinuity, i.e. the canopy hemline. The vorticity created in the boundary layer over the canopy upper surface is carried downstream, forming a free shear layer. In the flow field vorticity is confined to the this shear layer, outside it the flow is irrotational. Consequently, in this part of the fluid field a velocity potential can be defined. The wake flow created by bluff canopies is found to consist of a cluster of vortex rings which are shed periodically to the wake. Consequently, the axial aerodynamic force developed on the canopy will exhibit periodic behaviour. The resulting Strouhal number, has been determined to be about 0.13, based on the canopy projected area diameter. For all axisymmetric bluff canopies considered the calculated mean axial force coefficient, based on the canopy projected diameter, was found to be between 1.20 and 1.45. These values, together with the calculated pressure distribution and the wake flow periodicity, are in good agreement with known experiments. For parachute canopies performing an oscillatory axial motion the calculated results compare well with experimental data. However, it is shown that Morison's formula for this axial force is, generally, inadequate. Limited calculations of axial forces developed on the inflating parachute canopies agree with the sparse experimental data available. In the model the real flow field is simulated, basically, by a potential model. The canopy surface is replaced by a vortex ring panel lattice. Each panel contains a circular bound vortex ring which is located at one quarter panel length. For each panel the flow boundary conditions on the canopy surface are fulfilled along a control circle at three quarters of the panel length. A standing eddy which is generated by the high back-flow developed near the canopy hemline, on the canopy under surface is simulated by a standing vortex ring. The simulation of a two-dimensional discrete vortex separated wake is extended to the axisymmetric case by representing the separated wake with axisymmetric discrete vortex rings. The free shear layer emanating from the canopy hemline is represented by discrete free vortex rings which leave the canopy surface tangentially. At each time step in the calculation process a newly-created vortex ring is shed to the wake. In the vortex modelling of the separated wake a number of new elements have been introduced: -improvement of the near wake simulation by accounting for the standing eddy on the canopy under surface; -a simple method of calculating the newly created vortex ring strength & location; -reduction of the free parameters from two, the time step and the number of panels representing the canopy surface to one, i.e. the number of panels. Further model validation & implementation have been suggested. Methods of model development for asymmetric canopy representation have been discussed.

Mitochondria play a central role in lipid metabolism and pathology in obesity and type 2 diabetes mellitus. Mitochondria have been shown to associate with lipid droplets (LDs) in multiple tissues but the functional role of these peridroplet mitochondria (PDM) is unknown. This work reveals that PDM have unique protein composition and cristae structure, and remain adherent to the LD in the tissue homogenate. We developed an approach to isolate PDM based on their adherence to LDs. Comparison of purified PDM to cytoplasmic mitochondria reveals that (1) PDM have increased pyruvate oxidation, electron transport, and ATP synthesis capacities. (2) PDM have reduced beta oxidation capacity and depart from LDs upon activation of brown adipose tissue thermogenesis and beta oxidation. (3) PDM support LD expansion as Perilipin 5-induced recruitment of mitochondria to LDs increases ATP-dependent triacylglyceride synthesis. (4) PDM maintain a distinct protein composition due to uniquely low fusion-fission dynamics. We conclude that PDM represent a segregated mitochondrial population with unique structure and function that supports triacylglyceride synthesis. We suggest that increased mitochondrial recruitment to LDs may be part of a generalized adaptive response in physiological conditions that require LD expansion, such as post-prandial lipid synthesis and storage. Furthermore, PDM-mediated LD expansion may play a role in muscle and liver injury from lipotoxicity in conditions of nutrient excess, such as obesity and hyperlipidemia. A better understanding of PDM and LD biology may therefore lead to new therapies for lipotoxic tissue injury and insulin resistance.

This dissertation studies the impact that a networked society has on economicbehavior in the markets for labor and information. The first chapter examines how formerco-workers, and within that hiring-cohort co-workers, influence where a displaced workeris hired. The second chapter develops a theory of network formation that implies aprevalence of starting cohort members in an individuals connections and then tests thisprediction in the context of employee entrepreneurship. Finally, the third chapter studiesa decentralized market for information where bilateral links form the basis of trade andrelates it to the role that intellectual property protection plays in the information age.

This paper explores how trait information is represented in memory, and how the representation is used in forming an impression of a person. It was hypothesized that a trait description is encoded in a dual form: one component containing the traits themselves (the trait information), and another which contains the abstract summary derived from these traits (the header information). To test this hypothesis individuals matched the emotional tone (Study I) or the physical characteristics (Study 2) of a probe-trait with homogeneous (e.g., all positive or all negative) and mixed (e.g., half positive and half negative) trait descriptions). It was found that when these individuals had previously integrated the information (i.e., formed an impression), matching performance with mixed descriptions was inferior to that with homogeneous descriptions. However, when integration had not taken place prior to the match, the mixed descriptions were processed no differently than the homogeneous ones. Studies 3 and 4 attempt to separate processing of the header information from that of the trait information, and to demonstrate how the processing of one code affects the other. It was postulated that a new judgement will tend to be based on an old one (i.e., the header information), rather than on the given information, to the extent that (i) the similarity between the two judgements increases; and (ii) it becomes easier to retrieve the old judgement while making the new one. These hypotheses were generally supported by the analyses of judgements latencies in both studies. It was also hypothesized that the same factors that promote use of the header information, would result in a weaker memory for trait information. The strength of these representations was indicated by recognition accuracy (Study 3) and ease of paired-associate learning (Study 4). Both measures indicated that trait descriptions were more available following similar judgements than following unrelated judgements. To explain this phenomenon, we suggested that each similar judgement adds elaborations to the representation, whereas each unrelated judgement creates a new memory code for the trait description.