Doctor of Philosophy

dissertationPlasmonics, the study of light metal interactions, has shown great potential in the fields of spectroscopy, catalysis, medicine, and photovoltaics. There is significant interest in the design of metal nanoparticles that interact with specific wavelengths of light. By changing the size, shape, and metal composition, nanoparticles can be tuned to interact with different regions of the electromagnetic spectrum. Gold and silver are the two most common metals used in plasmonics, but are inefficient in the ultraviolet (UV) wavelength range and expensive. This has driven the research of plasmonics with non-noble metals that support plasmons in the UV and are cost-effective. Aluminum has been widely considered to be the ideal metal to fill this application has favorable plasmonic properties in the UV wavelength range and is cheap. However, Al is difficult to structure at the nanoscale due to its rapidly forming and chemically stable native oxide. Here we report the simple, large scale fabrication of Aluminum nanoparticle antennas. These nanoparticles have plasmon resonances in the UV, visible, near infrared, and infrared wavelengths. We demonstrate the utility of these nanoparticles as substrates for surface-enhanced infrared absorption spectroscopy, a wavelength range that is usually not associated with Aluminum. We also demonstrate that this fabrication technique allows for the fabrication of more complex nanoparticle geometries. These complex nanoparticles geometries have utility in both fundamental studies, and in surface-enhanced spectroscopies. We also demonstrate the potential of magnesium as a plasmonic metal. Magnesium is shown to support plasmon resonances from the UV to near infrared wavelengths. We investigate the plasmonic properties of nanostructured magnesium films and demonstrate that pure magnesium does not support sharp nanoscale features. By alloying magnesium with aluminum, its plasmonic and structural properties are improved

Preparation of multiblock copolymers via step-wise addition of l-lactide and trimethylene carbonate.

Poly(l-lactide) (PLA) is a bioderived and biodegradable polymer that has limited applications due to its hard and brittle nature. Incorporation of 1,3-trimethylene carbonate into PLA, in a block copolymer fashion, improves the mechanical properties, while retaining the biodegradability of the polymer, and broadens its range of applications. However, the preparation of 1,3-trimethylene carbonate (TMC)/l-lactide (LA) copolymers beyond diblock and triblock structures has not been reported, with explanations focusing mostly on thermodynamic reasons that impede the copolymerization of TMC after lactide. We discuss the preparation of multiblock copolymers via the ring opening polymerization (ROP) of LA and TMC, in a step-wise addition, by a ferrocene-chelating heteroscorpionate zinc complex, {[fc(PPh2)(BH[(3,5-Me)2pz]2)]Zn(μ-OCH2Ph)}2 ([(fcP,B)Zn(μ-OCH2Ph)]2, fc = 1,1'-ferrocenediyl, pz = pyrazole). The synthesis of up to pentablock copolymers, from various combinations of LA and TMC, was accomplished and the physical, thermal, and mechanical properties of the resulting copolymers evaluated

Obervational Model for Microarcsecond Astrometry with the Space Interferometry Mission

The Space Interferometry Mission (SIM) is a space-based long-baseline optical interferometer for precision astrometry. One of the primary objectives of the SIM instrument is to accurately determine the directions to a grid of stars, together with their proper motions and parallaxes, improving a priori knowledge by nearly three orders of magnitude. The basic astrometric observable of the instrument is the pathlength delay, a measurement made by a combination of internal metrology measurements that determine the distance the starlight travels through the two arms of the interferometer and a measurement of the white light stellar fringe to find the point of equal pathlength. Because this operation requires a non--negligible integration time to accurately measure the stellar fringe position, the interferometer baseline vector is not stationary over this time period, as its absolute length and orientation are time--varying. This conflicts with the consistency condition necessary for extracting the astrometric parameters which requires a stationary baseline vector. This paper addresses how the time-varying baseline is ``regularized'' so that it may act as a single baseline vector for multiple stars, and thereby establishing the fundamental operation of the instrument.Comment: 24 pages, 6 figure

How Insurers Competed in the Affordable Care Act's First Year

Prior to the Affordable Care Act (ACA), most states' individual health insurance markets were dominated by one or two insurance carriers that had little incentive to compete by providing efficient services. Instead, they competed mainly by screening and selecting people based on their risk of incurring high medical costs. One of the ACA's goals is to encourage carriers to participate in the health insurance marketplaces and to shift the focus from competing based on risk selection to processes that increase consumer value, like improving efficiency of services and quality of care. Focusing on six states—Arkansas, California, Connecticut, Maryland, Montana, and Texas—this brief looks at how carriers are competing in the new marketplaces, namely through cost-sharing and composition of provider networks

OA policies & traditional publishing agreements: Status of non-exclusive licenses in Canadian copyright law?

To ease the problem of paywall-blocked access to scholarly articles arising from publicly funded research, some universities have adopted a rights-retention OA policy. In this type of policy, faculty grant to the university a blanket non-exclusive license to make the accepted manuscript version of their scholarly articles publicly available in the university's research repository. But what happens if a university adopts an OA policy and faculty subsequently continue to sign publishers' standard publishing agreements that typically require an author to either transfer all copyrights or provide an exclusive license to the publisher? This presentation outlines a project that explores this question within Canadian copyright law

Predictors of negative beliefs toward the sexual rights and perceived sexual healthcare needs of people with physical disabilities in South Africa

Background: Although sexuality is a ubiquitous human need, recent empirical research has shown that people without disabilities attribute fewer sexual rights and perceive sexual healthcare to benefit fewer people with disabilities, compared to non-disabled people. Within a global context, such misperceptions have tangible, deleterious consequences for people with disabilities (e.g., exclusion from sexual healthcare), creating an urgent need for effective strategies to change misperceptions. Methods: To lay the groundwork for developing such strategies, we examined predictors of the recognition of sexual rights of people with physical disabilities within the South African context, derived from three key social psychological literatures (prejudice, social dominance orientation and intergroup contact), as well as the relationship between sexual rights and beliefs about sexual healthcare. Data were obtained through a cross-sectional survey, given to non-disabled South Africans (N = 1989). Results: Findings indicated that lack of recognition of the sexual rights for physically disabled people predicted less positive beliefs about the benefits of sexual healthcare. In turn, high levels of prejudice (both cognitive and affective) toward disabled sexuality predicted less recognition of their sexual rights, while prejudice (both forms) was predicted by prior contact with disabled people and possessing a social dominance orientation (cognitive prejudice only). Evidence was also obtained for an indirect relationship of contact and social dominance orientation on sexual healthcare beliefs through prejudice, although these effects were extremely small. Conclusion: Results are discussed in terms of their implications for rehabilitation, as well as national-level strategies to tackle negative perceptions of disabled sexuality, particularly in contexts affected by HIV.Implications for rehabilitation Findings demonstrate an empirical link between prejudice toward disabled sexuality, lack of recognition of sexual rights and viewing sexual healthcare of less benefit for disabled people. Consequently, there is need for increased attention to these dimensions within the rehabilitative context. Contact with disabled people, including dedicated interventions, is unlikely to meaningfully impact beliefs about the benefits of sexual healthcare

The factor structure of the Edinburgh Postnatal Depression scale in a South African peri-urban settlement

The factor structure of the Edinburgh Postnatal Depression scale (EPDS) and similar instruments have received little attention in the literature. The researchers set out to investigate the construct validity and reliability of the EPDS amongst impoverished South African women. The EPDS was translated into isiXhosa (using Brislin's back translation method) and administered by trained interviewers to 147 women in Khayelitsha, South Africa. Responses were subjected to maximum likelihood confirmatory factor analysis. A single factor structure was found, consistent with the theory on which the EPDS was based. Internal consistency was satisfactory (a =0.89)

PBL Student Projects and Sustainable Development Goals: A Case Study

Working with the Sustainable Development Goals can be a highly motivating factor in Problem Based Learning, especially if the solutions produced can be used afterwards and have an actual impact on people and communities. This paper describes how three engineering students from Aalborg University, Denmark, collaborated with the South African Organisation Green Shoots on bringing IT-supported Math education out to some of the most disadvantaged learners from townships and rural areas of the Western Cape. The project provided the Danish students with a unique learning experience and have a lasting impact on the communities involved. While the content of the project focused on bringing IT-supported Math education to learners in previously disadvantaged areas around the Western Cape, the project also provided valuable insight into how such students’ projects, where the outcomes benefit people and communities suffering from socio-economic challenges e.g. poverty, can be carried out. In addition to demonstrate that such projects are actually possible, we studied three critical aspects: How to ensure a good fit between learning objectives and project outcome, how to ensure that the project creates value for the partner organisation and communities, and how to ensure that the projects can be conducted without overloading the university supervisors. We believe that student projects focusing on SDGs have a big potential in terms of providing highly motivating student projects yet at the same time contribute to a better world through solutions that are being used even afterwards. However, our study was just a single case with one group of three students. We hope it will serve as inspiration for larger studies, where more quantitative data could be gathered in terms of how to establish a good framework around such projects, and in order to demonstrate the value for students and societies