Thesis (Ph. D.)--Oregon State University, 2000. / Includes bibliographical references (leaves 141-151).

Thesis (Ph. D.)--Oregon State University, 2001. / Typescript (photocopy). Includes bibliographical references (leaves 141-151). Also available on the World Wide Web.

This is an investigation of management in the mid-nineteenth century, and of changing roles and relationships of key figures on the Goodwood Estate. The study examines the workings of an estate belonging to the fifth Duke of Richmond, a committed protectionist during the period when he had to cone to terms with the Repeal of the Corn Laws. It considers the Duke's paternalism as expressed in his altitude to Repeal, in the daily running of his own estate, in his dealings with agents, farmers, estate workers and the local townspeople of Chichester. Richmond's paternalism was concerned with the moral improvement of those within his sphere, and the study examines the estate's financial resources which supported that paternalism, and the management structure which the fifth Duke created. The role of agent at Goodwood was particularly significant, and displayed change at a time of development for the estate, when a management hierarchy began to develop. The balances of rural society which Richmond maintained were in potential conflict with his task of leading improved agriculture. Such improvement needed dynamic change, which was not encouraged in a highly traditional, rural context such as the west of Sussex. The study tests Errile's concept of the golden age against the evidence from estate papers, particularly in the light of the depression of 1849-1853. Efficiency in the Duke's own farming was not enough: there was a need to spread agricultural improvement among his tenant farmers. Farms, farmers and farming practice indicate that the spread of good practice was no easy task, and that progress was made by employing a variety of tactics. The estate was subject to a variety of pressures which impinged on its authority structure, and the mid-century was far from being a time of untroubled progress and unqualified prosperity.

Total electron content (TEC) data measured from ground-based GPS receivers is compared to HF backscatter from ionospheric irregularities obtained by Super Dual Auroral Radar Network (SuperDARN) radars.  We present the first observations of a recurrent region of anomalous enhanced TEC at mid-latitudes over North America and attempt to characterize its frequency of occurrence.  Next, we examine the relationship of convection electric fields to the formation of a polar cap tongue of ionization (TOI) from mid-latitude plumes of storm enhanced density (SED) during a geomagnetic storm on 26 September 2011.  A channel of high density F region plasma was transported from the dayside ionosphere and into the polar cap by enhanced convection electric fields extending to mid-latitudes.  After the solar wind IMF conditions quieted and the dayside convection electric fields retreated to higher latitudes, an SED was observed extending to, but not entering, the dayside cusp region.  The source mechanism (enhanced electric fields) previously drawing the plasma from mid-latitudes and into the polar cap was no longer active, resulting in a fossil feature which persisted for several hours as it elongated in magnetic local time. Finally, we discuss ground surface effects on the HF backscatter observed by four SuperDARN radars. Monthly ground scatter occurrence rates are calculated for comparison with Arctic sea ice boundaries derived from satellite observations, showing reduced backscatter from regions covered by ice. / Master of Science

Providing molecular fingerprint information, vibrational spectroscopy is a powerful tool for chemical analysis. In the mid-infrared window, FT-IR spectroscopy and microscopy have been routinely used for sample characterization. In the near-IR window, near-infrared spectroscopy has been widely used for tissue analysis and for the detection of lipids in the arterial walls. Yet, these traditional linear spectroscopies have intrinsic limitations. FT-IR spectroscopy suffers from a poor spatial resolution and strong water absorption for the study of living systems. Near-infrared spectroscopy avoids water absorption, yet it suffers from a poor, millimeter-scale spatial resolution in tissue analysis. My thesis focuses on breaking these limitations through photoacoustic and photothermal detection approaches. The first part of my thesis is on improving the spatial resolution in catheter-based intravascular photoacoustic (IVPA) imaging. By near-infrared excitation of lipids and acoustic detection, IVPA allows depth-resolved identification of lipid-laden atherosclerotic plaque. Thus far, most IVPA endoscopes use multimode fibers, which do not allow tight focusing of photons. Recent experiments on pulse propagation in multimode graded-index fibers have shown a nonlinear improvement in beam quality. Here, we harness this nonlinear phenomenon for the fiber-delivery of nanosecond laser pulses. We built a photoacoustic catheter 1.4 mm outer diameter, offering a lateral resolution as fine as 30 μm within a depth range of 2.5 mm. Such resolution is one order of magnitude better than current multi-mode fiber-based intravascular photoacoustic catheters. At the same time, the delivered pulse energy can reach as high as 20 μJ, which is two orders of magnitude higher than that of an optical resolution photoacoustic endoscope built with single-mode fiber. These improvements are expected to promote the biomedical application of photoacoustic endoscopes which require both high resolution and high pulse energy. Based on the technical advances, my thesis work further demonstrated longitudinal imaging of the same plaque in the same living animal. Recently developed mid-infrared photothermal (MIP) microscopy overcomes the limitations in FT-IR microscopy by probing the IR absorption-induced photothermal effect using visible light. MIP microscopy yields sub-micrometer spatial resolution with high spectral fidelity and much-reduced water background. The second part of my thesis work pushes the physical limits of MIP microscopy in aspects of detection sensitivity and imaging speed using two approaches. First, taking advantage of the interference scattering effect, the scattering signal from the sample can be greatly enhanced. Together with the relatively large infrared absorption coefficient, the sensitivity of the infrared spectrum is greatly improved, and single virus detection is achieved. Second, by using fluorescence as a thermo-sensitive probe, the temperature raise by infrared absorption can be retrieved in a more efficient way and much higher imaging speed and sensitivity are thus accomplished.

This thesis describes a series of experiments that were undertaken to extend the limits of output power and wavelength coverage of optically pumped mid-infrared lasers. Initially, two new cw Raman lasers operating at wavelengths of 11.5 and 12.5 pm were developed. Maximum output powers of 650 add 150 mW were produced, with pump powers of 11 and 3.3 W, respectively. The effect of the pump offset on the output power was then determined by measuring the efficiency of an NH3 laser pumped at frequency offsets of 94 and 274 MHz. In lasers ope rating in pure NH3 the larger pump offset required a greater pump intensity to reach threshold, but efficiency increased with pump offset. Higher NH3 pressures could be used at larger pump offsets and the improved efficiency was attributed to reduced saturation effects at the higher operating pressures. Experiments carried out with NH3 inversion lasers have greatly increased the output powers available at a large number of wavelengths in the 10 to 14 um range. In a buffered NH3 mixture, the sR(5,0) transition was pumped on resonance. Collisions with either N2 or Ar buffer gases were effective in thermalizing the rotational populations in the v2=1 vibrational level and producing gain on a wide range of frequencies. Output powers as large as 3.5 W on a single Tine and greater than 5 W multi-line were produced, at efficiencies of 20 and 30 % respectively. The number of lasing wavelengths increased substantially, as more than forty ortho-NH3 transitions were observed to lase in a grating-tuned cavity. The optical pumping technique was then used for the first time to produce line-tunable lasing on para-NH3 transitions. The sR(5,1) transition was pumped near resonance and 24 para-transitions were observed to lase. In total, lasing was achieved on 65 different transitions in 14NHg, with wave lengths of 10.3 to 13.8 pm. / Thesis / Master of Science (MS)

First time ionospheric refractive index values have been determined at mid latitudes using frequency switched SuperDARN plasma convection velocity estimates. Previous works have found a disparity between high latitude SuperDARN plasma convection velocities and those made by other devices. It was noted that the scattering volume’s refractive index was being neglected when estimating plasma convection velocities, meaning a correction factor was needed in order to more accurately reflect other measurements. Later work proposed a solution which implemented frequency switching in SuperDARN radars and determined a single correction factor based off of many years of data. We present case study driven research which applies the principles of these previous works to mid latitudes in an attempt to determine the refractive effect in mid latitude SuperDARN plasma convection velocity data by examining frequency switched quiet time ionospheric scatter. It was found that the 1/2 hop ionospheric scatter exhibited little to no measurable refractive effect (n ∼ 1), while the 11/2 hop ionospheric scatter tended to exhibit measurable refractive effects (n ∼ 0.7). This is then expanded to a storm-time 1/2 hop ionospheric scatter case study. It was again found that the refractive effects were nearly negligible (n ∼ 1), indicating that the 1/2 hop plasma convection velocities reported by mid latitude SuperDARN radars only require a very small correction factor, if any at all. / Master of Science

Thesis advisor: Mark D. Behn / The global mid ocean ridge system is segmented by transform faults and non-transform discontinuities. Oceanic transform faults display distinct morphology characterized by a deep valley and shallow transverse ridges on either side of the valley. Although the morphology of oceanic transform faults is known to first order, there is no consensus on the processes that form the transform valley and/or the adjacent transverse ridges. To date, most models of transform morphology attribute these features to either transform-normal extension or to shear stresses induced by slip along the fault. In this thesis, I compile bathymetric data along 16 major transform faults on the Mid-Atlantic Ridge and identify the key morphological properties of each transform. Specifically, I estimate transform valley width, depth, and total relief measured from the valley floor to the adjacent transverse ridges. The strongest correlation is between the relief and maximum depth, but there is a weaker correlation between maximum depth and valley width. These morphologic properties are then compared to key fault parameters such as slip rate, fault-normal compression/extension rate, thermal area, and the seismic coupling ratio, which is defined as the fraction of total fault slip that occurs seismically. These comparisons are used to test models that describe mechanisms of the formation of the transform valley. The strongest correlation is between the fault thermal area and valley half width. This suggests that the width of the transform valley may be controlled by the shear stress applied to the fault as it slips. By contrast, the data are not consistent with a model in which the valley is created by extension across the fault, because our data show that the maximum transform valley depth increases with compression and not extension. / Thesis (MS) — Boston College, 2024. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Earth and Environmental Sciences.

Over the years there has been significant research around the misspecification of the Capital Asset Pricing Model (CAPM), which challenges the linear relationship between beta and market returns. One of the biggest challenges relates to the “small-firm effect,” which states there are two classifications of stocks (large and small) and that the companies with small-market capitalizations have higher returns. However, the definition of a small-cap is vague and there has been little focus in academia on the stocks in the middle-market capitalization deciles. Despite this, institutional and retail investors created the “mid-cap” category in the early 1990s and, since then, the risk-adjusted returns have been exceptional, relative to small- and large-cap stocks. This study examined mid-cap stocks from an academic perspective and delves into the “mid-cap myth” by evaluating the category over the past 85 years to answer the question around whether mid-caps are superior to other asset class. The results revealed that the highly touted and advertised mid-cap stock performance premium during the 1980-2013 time period was statistically insignificant. Moreover, mid-caps did have superior risk-adjusted returns over the extended time period studied (1928 to 2014); however, these superior returns relative to small-caps were not driven by the uniqueness of the mid-sized companies, but by the underperformance of small-cap stocks, specifically small-cap growth stocks. When studying the behavior or migration of mid-size companies, they do not appear to exhibit unusual behavior relative to companies with smaller market capitalizations, especially in the area of mergers and acquisitions. Thus, the question becomes why small-cap companies underperform relative to their risk level. The answer lies in the inclusion of the NASDAQ stocks to the CRSP database after 1972. This change not only doubled the number of stocks deemed small-caps, but also added a significant number of unprofitable fast-growing companies to the small-cap growth category, specifically in the technology and healthcare industries. The study benefits practitioners by providing insight into the omnipresent claim of mid-cap outperformance from 1980-2014, while also benefiting academia by providing more insight into small-caps’ underperformance during this period and how investigating small-cap growth companies further could add insight into the viability or magnitude of the size and value premium going forward.

The frequency, magnitude, and atmospheric drivers of winter hydroclimatic conditions conducive to snowmelt in western Canada were evaluated. These hydroclimatic variables were linked to the mid-winter break-up of river ice that included the creation of a comprehensive database including 46 mid-winter river ice break-up events in western Canada (1950-2008) and six events in Alaska (1950-2014). Widespread increases in above-freezing temperatures and spatially diverse increases in rainfall were detected over the study period (1946-2012), particularly during January and March. Critical elevation zones representing the greatest rate of change were identified for major river basins. Specifically, low-elevation (500-1000 m) temperature changes dominated the Stikine, Nass, Skeena, and Fraser river basins and low to mid-elevation changes (700-1500 m) dominated the Peace, Athabasca, Saskatchewan, and Columbia river basins. The greatest increases in rainfall were seen below 700 m and between 1200-1900 m in the Fraser and at mid- to high-elevations (1500-2200 m) in the Peace, Athabasca, and Saskatchewan river basins. Daily synoptic-scale atmospheric circulation patterns were classified using Self-Organizing Maps (SOM) and corresponding hydroclimatic variables were evaluated. Frequency, persistence, and preferred shifts of identified synoptic types provided additional insight into characteristics of dominant atmospheric circulation patterns. Trend analyses revealed significant (p < 0.05) decreases in two dominant synoptic types: a ridge of high pressure over the Pacific Ocean and adjacent trough of low pressure over western Canada, which directs the movement of cold, dry air over the study region, and zonal flow with westerly flow from the Pacific Ocean over the study region. Conversely, trend analyses revealed an increase in the frequency and persistence of a ridge of high pressure over western Canada over the study period. However, step-change analysis revealed a decrease in zonal flows and an increase in the occurrence of high-pressure ridges over western Canada in 1977, coinciding with a shift to a positive Pacific Decadal Oscillation regime. A ridge of high pressure over western Canada was associated with a high frequency and magnitude of above-freezing temperatures and rainfall in the study region. This pattern is highly persistent and elicits a strong surface climate response. A ridge of high pressure and associated above-freezing temperatures and rainfall was also found to be the primary driver of mid-winter river ice break-up with rainfall being a stronger driver west of the Rocky Mountains and temperature to the east. These results improve our understanding of the drivers of threats to snowpack integrity and the generation of extreme hydrologic events. / Graduate