Health, Labour, and the Environment: A Social Economic Analysis

In this dissertation, I explore several social economic topics, including health, labour, and the environment. Although the chapters of this dissertation explore diverse subjects, the overall theme is to analyze important social issues and their policy implications. I made use of a variety of rich datasets, as well as employing various econometric analyses, often supported by a theoretical model, to examine the research topics identified in each chapter. In Chapter 1, I explore a 1997 policy change, which altered eligibility requirements for Disability Insurance (DI). While DI in Canada provides income support to millions, it has also been criticized for creating a disincentive for labour force participation. The 1997 change affected some Canadians, but not others, creating a natural experiment setting in which to explore this policy. I found that, following the tightening of eligibility requirements, relative labour force participation for women did increase, but their level of employment did not. There was little effect for men. This distinction between labour force participation and employment is a crucial one in this context: it indicates that what may appear to be individuals returning to work after not being eligible for DI may instead be individuals returning to the labour force, but unable to find suitable employment. In Chapter 2, I examine whether searching for health information on the internet acts as a complement or substitute for the demand for information from physicians (proxied by physician visits). I found that the effect on physician-based information hinged on an individuals prior trust in the formal medical sector: those with high prior trust tended to use health information searching on the internet as a complement for physician visits, whereas, those with low prior trust substituted away from physician visits in favour of information found online. The results were very similar when a telehealth program was examined instead of internet-based information. Further, those who were online health information searchers also tended to be more likely to use a telehealth program. This is a reassuring result, as it may mean that those who substituted out of the formal medical sector, in favour of health online information, may also be using the more quality-controlled telehealth programs. In Chapter 3, I explore how attitudes towards the environment affect behaviours in five key areas of environmental-related household consumption: waste generation and recycling, energy use, organic food consumption, personal transport, and water use. Prior studies have not examined these areas together, often due to data restrictions, and not in the context of environmental attitudes. Using a modelling procedure that allows for the errors in these five areas to be correlated, I found that attitudes were often a more significant predictor of ones behaviour than the financially driven policy implemented in the area

Westward Growth of Laurentia by Pre–Late Jurassic Terrane Accretion, Eastern Oregon and Western Idaho, United States

New U-Pb and Sm-Nd data from the Blue Mountains province, eastern Oregon and western Idaho, clarify terrane correlations and regional evolution of the western Laurentian plate margin during Mesozoic time. We report an Early Jurassic age for a red tuff unit at Pittsburg Landing, Idaho, which is 25 m.yr. older than previous Middle Jurassic estimates. In the Coon Hollow Formation at Pittsburg Landing and at the type location on the Snake River, chemical abrasion thermal ionization mass spectrometry U-Pb zircon ages on interbedded tuff and detrital zircon U-Pb maximum depositional ages indicate that deposition spanned ca. 160–150Ma, entirely during Late Jurassic time. Detrital zircon U-Pb ages represent local Wallowa arc basement and regional magmatic sources spanning ca. 290–140 Ma. Mudrock Nd isotope compositions of the Coon Hollow Formation record an increase in juvenile magmatism consistent with regional Late Jurassic trends in western North American magmatic systems. These data show that the Coon Hollow Formation is not part of a Middle Jurassic overlap assemblage, as has been historically interpreted. Instead, we propose that the Coon Hollow Formation is part of a belt of suprasubduction-zone extensional back-arc basins that formed in latest Jurassic time due to a well-documented period of trench retreat in the western United States. Our new data require that the underlying Wallowa terrane was accreted to and received detritus from western North America by ca. 160 Ma (early Late Jurassic). This minimum estimate for the age of terrane accretion in western Idaho and eastern Oregon is substantially earlier than previous estimates (∼135–118 Ma). In the Blue Mountains region, westward expansion of Laurentia was accomplished by accretion of arc terranes to the North American craton prior to Late Jurassic time

Triplex addressability as a basis for functional DNA nanostructures

Here, we present the formation of a fully addressable DNA nanostructure that shows the potential to be exploited as, for example, an information storage device based on pH-driven triplex strand formation or nanoscale circuits based on electron transfer, The nanostructure is composed of two adjacent hexagonal unit cells (analogous to naphthalene) in which each of the eleven edges has a unique double-stranded DNA sequence, constructed using novel three-way oligonucleotides. This allows each ten base-pair side, just 3.4 nm in length, to be assigned a specific address according to its sequence. Such constructs are therefore an ideal precursor to a nonrepetitive two-dimensional grid on which the "addresses" are located at a precise and known position. Triplex recognition of these addresses could function as a simple yet efficient means of information storage and retrieval. Future applications that may be envisaged include nanoscale circuits as well as subnanometer precision in nanoparticle templating. Characterization of these precursor nanostructures and their reversible targeting by triplex strand formation is shown here using gel electrophoresis, atomic force microscopy, and fluorescence resonance energy transfer (FRET) measurements. The durability of the system to repeated cycling of pH switching is also confirmed by the FRET studies

Denise Tumpane and Karren Harrington to Dear Mr. Meredith (Undated)

https://egrove.olemiss.edu/mercorr_pro/1742/thumbnail.jp

Age and Isotopic Investigations of the Olds Ferry Terrane and its Relations to Other Terranes of the Blue Mountains Province, Eastern Oregon and West-Central Idaho

The Olds Ferry terrane of the Blue Mountains province is one of the numerous accreted terranes that comprise the western North American Cordillera. The Blue Mountains province is located in central and eastern Oregon, western Idaho, and extreme southeastern Washington, and is a crucial link in reconstructions of the North American Cordillera due to its position in an area with few visible terranes between the more extensively exposed terranes to the south in California and Nevada and to the north in Canada and Alaska. New field evidence and U-Pb zircon geochronology for volcanics within the sedimentary onlap assemblages overlying the Wallowa and Olds Ferry volcanic arc terranes provide evidence for an earlier connection between the terranes than has previously been recognized. The boundary between the Izee and Olds Ferry strata is an angular unconformity based on geochronological data, the consistent angular discordance between the Olds Ferry and Izee strata, and the presence of locally derived volcanic and plutonic clasts of the Olds Ferry arc in the basal Weatherby conglomerate of the Izee terrane. I correlate this unconformity with that present at the base of the transgressive fluvial-deltaic and marine sequence of the Coon Hollow Formation of the Wallowa terrane based on new ages from units bracketing this unconformity. Ages for the basal Coon Hollow and Weatherby Formations allow these to be correlative sedimentary onlap packages and thus demonstrate the connection between the Wallowa and Olds Ferry terranes by Early Jurassic time. Detailed field mapping and geochronology was used to split the Huntington Formation into two members, and establish their relationships to underlying plutonic rocks and the overlying sediments of the Izee basin onlap sequence. Geochemical data support splitting the Huntington Formation into two members, and support a model of eruption in an island-arc environment with a combination of mantle and crustal magma sources distinct from the island arc that is the Wallowa terrane. Geochronologic and structural constraints also provide evidence that Olds Ferry volcanism continued well into the Early Jurassic, and that the lower and upper members of the Huntington Formation are separated by an angular unconformity and rest with nonconformity on the underlying plutonic units. Precambrian xenocrystic zircons in lower and upper Huntington Formation volcanics indicate that the Olds Ferry terrane was proximal to cratonal North America during much of its history. Age correlations made possible by new U-Pb geochronology indicate that the Olds Ferry and Wallowa arcs may have been active concurrently in the early Late Triassic, followed by a period in the Late Triassic when the Olds Ferry arc was volcanically active while the Wallowa arc was quiescent

Self-assembly Strategies for Functional DNA Nanostructures

The technological revolution of the twentieth century was famously subject to Moore’s law which related the rate of growth to the ability to scale-down the size of the components – size matters. Several decades later we are, however, approaching the limit of what is possible with silicon wafers. Moreover, the world is becoming ever-more environmentally conscious and technology is no longer merited simply by its short-term possibilities but its long-term consequences are also under scrutiny. The looming implication is that we need to change the materials on which we base our technology, and improve their efficiency. There are many options available to the researchers including carbon nanotubes, the manipulation of which is briefly touched upon here. The main focus of this thesis is, however, the bio-inspired approach – using simple assemblies of DNA fragments and lipid bilayers in water – to create miniscule structures with an inbuilt function that may one day operate as a nano-device. The fact that DNA possesses an inherent molecular recognition code makes it the ideal candidate for building information-rich structures. The studies in this thesis have concentrated on building the elements of a non-repetitive two-dimensional DNA network – forming structures that are less than 10 nm in diameter and that can be functionalised with a precision of less than 1 nm. Such a network could be used as e.g. a directed energy transfer circuit. Light, pH and temperature have been used to control the structures in a predictable manner – simple energy transfer steps across the structures have also been probed and we have established that relatively small changes in pH can be used to switch on and off communication between two points in the network. The fundamental interactions between a lipid bilayer and DNA are also considered, in order to understand how best to immobilise a DNA network on such a semi-fluidic support. One important finding is that there are both different interaction geometries and binding efficiencies for varying lengths of DNA in cationic lipid complexes, which may have serious implications not just in the field of nanotechnology but in the pursuit of such lipoplexes as vectors for antisense therapeutics. A second study shows that DNA strands can be tethered to a neutral lipid membrane using a porphyrin as a hydrophobic anchor and that energy and electron transfer processes can subsequently take place within such systems

Self-assembly Strategies for Functional DNA Nanostructures

The technological revolution of the twentieth century was famously subject to Moore’s law which related the rate of growth to the ability to scale-down the size of the components – size matters. Several decades later we are, however, approaching the limit of what is possible with silicon wafers. Moreover, the world is becoming ever-more environmentally conscious and technology is no longer merited simply by its short-term possibilities but its long-term consequences are also under scrutiny. The looming implication is that we need to change the materials on which we base our technology, and improve their efficiency. There are many options available to the researchers including carbon nanotubes, the manipulation of which is briefly touched upon here. The main focus of this thesis is, however, the bio-inspired approach – using simple assemblies of DNA fragments and lipid bilayers in water – to create miniscule structures with an inbuilt function that may one day operate as a nano-device. The fact that DNA possesses an inherent molecular recognition code makes it the ideal candidate for building information-rich structures. The studies in this thesis have concentrated on building the elements of a non-repetitive two-dimensional DNA network – forming structures that are less than 10 nm in diameter and that can be functionalised with a precision of less than 1 nm. Such a network could be used as e.g. a directed energy transfer circuit. Light, pH and temperature have been used to control the structures in a predictable manner – simple energy transfer steps across the structures have also been probed and we have established that relatively small changes in pH can be used to switch on and off communication between two points in the network. The fundamental interactions between a lipid bilayer and DNA are also considered, in order to understand how best to immobilise a DNA network on such a semi-fluidic support. One important finding is that there are both different interaction geometries and binding efficiencies for varying lengths of DNA in cationic lipid complexes, which may have serious implications not just in the field of nanotechnology but in the pursuit of such lipoplexes as vectors for antisense therapeutics. A second study shows that DNA strands can be tethered to a neutral lipid membrane using a porphyrin as a hydrophobic anchor and that energy and electron transfer processes can subsequently take place within such systems

Self-assembly Strategies for Functional DNA Nanostructures

The technological revolution of the twentieth century was famously subject to Moore’s law which related the rate of growth to the ability to scale-down the size of the components – size matters. Several decades later we are, however, approaching the limit of what is possible with silicon wafers. Moreover, the world is becoming ever-more environmentally conscious and technology is no longer merited simply by its short-term possibilities but its long-term consequences are also under scrutiny. The looming implication is that we need to change the materials on which we base our technology, and improve their efficiency. There are many options available to the researchers including carbon nanotubes, the manipulation of which is briefly touched upon here. The main focus of this thesis is, however, the bio-inspired approach – using simple assemblies of DNA fragments and lipid bilayers in water – to create miniscule structures with an inbuilt function that may one day operate as a nano-device. The fact that DNA possesses an inherent molecular recognition code makes it the ideal candidate for building information-rich structures. The studies in this thesis have concentrated on building the elements of a non-repetitive two-dimensional DNA network – forming structures that are less than 10 nm in diameter and that can be functionalised with a precision of less than 1 nm. Such a network could be used as e.g. a directed energy transfer circuit. Light, pH and temperature have been used to control the structures in a predictable manner – simple energy transfer steps across the structures have also been probed and we have established that relatively small changes in pH can be used to switch on and off communication between two points in the network. The fundamental interactions between a lipid bilayer and DNA are also considered, in order to understand how best to immobilise a DNA network on such a semi-fluidic support. One important finding is that there are both different interaction geometries and binding efficiencies for varying lengths of DNA in cationic lipid complexes, which may have serious implications not just in the field of nanotechnology but in the pursuit of such lipoplexes as vectors for antisense therapeutics. A second study shows that DNA strands can be tethered to a neutral lipid membrane using a porphyrin as a hydrophobic anchor and that energy and electron transfer processes can subsequently take place within such systems