Verbal communication relies heavily on the ability to effortlessly produce intended words to express a meaning. This capacity is frequently impaired in individuals with aphasia, and impairment often lasts well into the chronic stages. However, the nature of anomia can vary. Phonological neighborhood density (PND) is one feature of words which has been shown to impact the ease of retrieval in speakers with aphasia; words with more similar-sounding neighbors are easier to retrieve because the neighbors help activate the target. However, it is unclear how different types of lexical access breakdowns affect the impact of PND. The aim of this project was to analyze the relationship between word retrieval accuracy, speech error patterns, and PND in individuals with aphasia. Twenty-two participants with various types and severities of aphasia named 200 single-syllable line drawings. WebFit, an online software program designed to fit naming data to a theoretical model of word retrieval, was used to characterize participants' error patterns by calculating the strength of connections within the lexicon, as well as the rate of decay. Analyses confirmed previous findings that participants with all types of breakdown achieved lower rates of overall accuracy. Weaker connections between semantic knowledge and words resulted in a more errors that were close to the target, relative to errors with no relationship to the target. Individuals with more severe impairments of the semantic-lexical connections and the lexical-phonological connections produced words with many neighbors more accurately than words with fewer neighbors. Implications for initial therapy target selection and directions for further research are discussed.

This papers is divided into numbered sections. The equations are numbered anew in each section, and equation numbers are always enclosed in parentheses. Merely the equation number is given when referring to an equation in the same section as the references; otherwise the section number is prefixed. Thus equation (4) refers to the fourth equation of the same section as the reference, and equation (2.2) refers to the second equation of the second section.

A major challenge in ecology is to understand intraspecific variation in life histories. Variation in resource availability can lead to differences in reproductive allocation and life histories. Grasshoppers are a good organism for the study of variation in life histories, since they exhibit life history plasticity in response to biotic and environmental factors. An optimality model for grasshoppers was developed that predicts optimal total allocation to reproduction and optimal effort-per-offspring as functions of resource availability and mortality. Relative allocation to reproduction is predicted to increase with resource availability, while relative allocation to survival declines. A resource-based trade-off between egg size and number does not exist, as optimal egg size is predicted to be independent of resource intake. I examined if changes in reproductive allocation and survival of Melanoplus sanguinipes (Fabricus) under a range of resource availabilities fit the predictions of the model. The patterns of reproductive allocation and survival in the field were in qualitative agreement with the predictions. I examined the importance of density, resources, and parasitism on the life history patterns of grasshoppers. I conducted an experiment to examine if differences in reproductive allocation of M. sanguinipes are primarily explained by exploitative competition. Per capita resource availability explained a significant amount of the variation in reproduction , as expected with exploitative competition. M. sanguinpes grasshoppers appeared to trade off resource allocation to reproduction for that of allocation to survival, because per capita resource availability did not affect survival. Careful examinations of changes in life history characteristics in response to parasitism are lacking, despite the fact that parasites often influence resource availability for the host. I investigated the effects of a grasshopper ectoparasitic mite on grasshopper reproduction and survival. Mites had small effects on grasshopper survival. As predicted, both species had reduced initial and total reproduction, and completed development of a lower percentage of ovarioles initiated when parasitized. These experiments act to expand our knowledge of life history theory and further our understanding of grasshopper life history variation and population fluctuations.

In Particle Image Velocimetry (PIV), the number of particle images per interrogation region, or particle image density, impacts the strength of the correlation and, as a result, the number of valid vectors and the measurement uncertainty. Therefore, any a-priori estimate of the accuracy and uncertainty of PIV requires knowledge of the particle image density. An autocorrelation-based method for estimating the local, instantaneous, particle image density is presented. Synthetic images were used to develop an empirical relationship based on how the autocorrelation peak magnitude varies with particle image density, particle image diameter, illumination intensity, interrogation region size, and background noise. This relationship was then tested using images from two experimental setups with different seeding densities and flow media. The experimental results were compared to image densities obtained through using a local maximum method as well as manual particle counts and are found to be robust. The effect of varying particle image intensities was also investigated and is found to affect the particle image density.

The tart cherry (Prunus cerasus) is the most significant fruit tree crop in Utah, accounting for roughly 51% of the total statewide commercial fruit acreage. In order to accommodate harvesting equipment, tart cherries are grown in conventional orchards with large trees spaced up to 5.5 meters apart. New methods of harvest are adapted to smaller trees in tighter spaced high density (HD) orchards. HD orchards bear fruit earlier in the orchard life than conventional orchards, but likely require different pruning and management strategies, which have not yet been determined for tart cherry. Experimental HD orchards were used to determine the type of renewal pruning cuts to maintain orchard productivity, and to determine whether mechanical pruning (hedging) could be used to maintain tree size. It was found that when removing branches during pruning, leaving the branch stub at least 10 cm long greatly increases the likelihood of getting adequate renewal growth. Mechanical hedging at bloom or 45 days after bloom did not change yields or fruit quality when applied to a well-pruned and maintained orchard. Spray pattern analysis in these canopies suggested that hedging creates a more consistent canopy density than unhedged HD canopies. This research provides distinct guidelines on renewal pruning of tart cherry to maintain productivity, and shows that mechanical hedging strategies can be a viable option for maintaining tree size in HD plantings without increasing pruning costs.

An (e,2e) electron scattering spectrometer has been constructed and used for the first time to investigate the spectral momentum density of the valence bands of a solid target. This technique provides fundamental information about the electronic structure of both crystalline and amorphous solids. The three fundamental quantities, the band structure, electron density of states, and electron momentum distribution can be simultaneously derived from the measured (e,2e) cross section. A review of single electron and (e,2e) scattering theory is given with an emphasis on scattering from solids. The effects of multiple scattering are discussed and a method of deconvoluting those effects from the measured (e,2e) cross section is developed. There is a detailed description of the spectrometer design and operation with particular attention given to the electron optics and voltage distribution. The algorithms and software for computer aided data acquisition and analysis are also outlined, as is error analysis. The techniques employed in the preparation and characterization of extremely thin film samples of a-C and single crystal graphite are described An analysis of the data taken for a-C samples is complementary experiments and theory for graphite, diamond, and a-C which are given in a review of the literature. The existence of a definite dispersion relation ε(q) in amorphous carbon is demonstrated. The a-C band structure appears to be more similar to that of graphite than to that of diamond, however it differs significantly from both in some respects. The measured spectral momentum density seems compatible with a model of a-C based on small, randomly-oriented islands of quasi-2D graphite-like continuous random network structures. However, no definitive interpretations can be made until higher resolution experiments are performed on both a-C and single crystal graphite.

This study investigates the response of lightning to the El Niño Southern Oscillation (ENSO) in the vicinity of the U.S. Gulf Coast region and nearby adjacent waters of the Gulf of Mexico, for the years 1995-2002. The Gulf Coast region was selected for this study because of its high flash density (Orville and Huffines, 2001) and because it is an area where the ENSO fingerprint is very clearly demonstrated on both temperature and precipitation patterns (CPC, 2002). Additionally, this geographic domain roughly matches the only known study on this topic (Goodman et al., 2000). Winter is the season of greatest response to ENSO (CPC, 2004), and past studies show that summer has the most lightning activity (e.g., Orville and Huffines, 2001). The temporal domain of the study is restricted to 1995 and beyond, as this follows a system-wide upgrade of the National Lightning Detection Network (NLDN) that improved overall flash detection efficiency (Cummins, et. al.1998; Wacker and Orville, 1999). Both qualitative and quantitative methods were employed to explore the lightning data for ENSO teleconnections. Mean flash density maps were constructed for the complete period of record, individual months and the winter and summer seasons. Maps were visually examined for qualitative comparison with past climatologies and the Goodman et al., (2002) ENSO study. Additionally, monthly flash deviations are computed, visualized and correlated with the Niño 3.4 SST anomaly for all months in the study, seeking out variations in both the amount of flash deviation and spatial properties. Abundant literature exists on both ENSO and lightning individually. This study offers an insight into their intersection.

Philosophiae Doctor - PhD / Investigation of the acoustic impedance variations in the upper shallow marine sandstone reservoirs was extensively studied from 10 selected wells, namely: F-O1, F-O2, E-M4, E-CN1, E-G1, E-W1, F-A10, F-A11, F-A13, and F-L1 in the Bredasdorp Basin, offshore, South Africa. The studied wells were selected randomly across the upper shallow marine interval with the purpose of conducting a regional study to assess the variations in the acoustic impedance across the reservoirs using wireline log and core data. The datasets used in this study were geophysical wireline logs, conventional core analysis, geological well completion reports, core plugs, and core samples. The physical rock properties such as lithology, fluid type, and hydrocarbon bearing zone were identified while different parameters like the volume of clay, porosity, and water saturation were quantitatively estimated. The reservoirs were penetrated at a different depth ranging from a shallow depth of 2442m at well F-L1 to a deeper depth of 4256.7m at well E-CN1. The average volume of clay, average effective porosity from wireline log, and average water saturation ranged from 8.6%- 43%, 9%- 16% and 12%- 68%, respectively. Porosity distribution was fairly equal across the field from east to west except in well F-A10, F-A13, and F-A11 where a much higher porosity was shown with F-A13 showing the highest average value of 16%. Wells E-CN1, E-W1, F-O1, F-L1 and E-G1 had lower porosity with E-CN1 showing the lowest average value of 9%. The acoustic properties of the reservoirs were determined from geophysical wireline logs in order to calculate acoustic impedance and also investigate factors controlling density and acoustic velocities of these sediments. The acoustic impedance proved to be highest on the central to the western side of the field at E-CN1 with an average value of 11832 g/cm3s whereas, well F-A13 reservoir in the eastern side of the field proved to have the lowest average acoustic impedance of 9821 g/cm3s. There was a good linear negative relationship between acoustic impedance and porosity, compressional velocity vs porosity and porosity vs bulk density. A good linear negative relationship between acoustic impedance and porosity was obtained where the reservoir was homogenous, thick sandstone. However, interbedded shale units within the reservoir appeared to hinder a reliable correlation between acoustic impedance and porosity. The cross-plots results showed that porosity was one of the major factors controlling bulk density, compressional velocity (Vp) and acoustic impedance. The Gassmann equation was used for the determination of the effects of fluid substitution on acoustic properties using rock frame properties. Three fluid substitution models (brine, oil, and gas) were determined for pure sandstones and were used to measure the behaviour of the different sandstone saturations. A significant decrease was observed in Vp when the initial water saturation was substituted with a hydrocarbon (oil or gas) in all the wells. The value of density decreased quite visibly in all the wells when the brine (100% water saturation) was substituted with gas or oil. The fluid substitution affected the rock property significantly. The Vp slightly decreases when brine was substituted with water in wells F-A13, F-A10, F-O2, F-O1 F-A11, F-L1, and E-CN1. Wells E-G1, E-W1, and E-M4 contain oil and gas and therefore showed a notable decrease from brine to oil and from oil to gas respectively. Shear velocity (Vs) remained unaffected in all the wells. The acoustic impedance logs showed a decrease when 100% water saturation was replaced with a hydrocarbon (oil or gas) in all the wells. Clay presence significantly affects the behaviour of the acoustic properties of the reservoir rocks as a function of mineral type, volume, and distribution. The presence of glauconite mineral was observed in all the wells. Thirty-two thin sections, XRD and SEM/EDS from eight out of ten wells were studied to investigate lithology, diagenesis and the effect of mineralogy on porosity and acoustic properties (Compressional velocity and bulk density) within the studied reservoir units. Cementation (calcite and quartz), dissolution, compaction, clay mineral authigenesis, and stylolitization were the most significant diagenetic processes affecting porosity, velocity, and density.Well E-CN1 reservoir quality was very poor due to the destruction of intergranular porosity by extensive quartz and illite cementation, and compaction whereas well F-A13 show a highly porous sandstone reservoir with rounded monocrystalline quartz grain and only clusters of elongate to disc-like, authigenic chlorite crystals partly filling a depression within altered detrital grains. Overall, the results show that the porosity, lithology mineralogy, compaction and pore fluid were the major factors causing the acoustic impedance variations in the upper shallow marine sandstone reservoirs. / 2021-09-01

Vehicle miles of travel (VMT) is a key indicator of travel demand in the United States. Since 1995 total VMT and VMT per capita has fluctuated, with notable declines in the late 2000s and accelerated increases in the last 7 years. Since 1995, the National Household Travel Survey (NHTS) has tracked the household share of total VMT to shed light on the demographic and behavioral data behind personal vehicle travel. The household share of VMT, while still a majority, has declined every NHTS year since at least 1995. Meanwhile, household VMT has stagnated around 2.25 trillion miles since the 2001 survey. With such unprecedented travel demand changes, the current transportation technology revolution, and the climate of uncertainty, it is critical to understand why household VMT is changing and how this might affect future roadway demand. This thesis examines demographic, socioeconomic and behavioral factors that influence VMT, including both factors with existing research and some untraditional factors, using new data and methodologies.

This thesis seeks to address energy efficient design in a temperate climate in typical small, medium density housing, particularly in housing for the aged. The connections between energy efficient design and small, medium density housing were identified as contemporary issues related to Australian Government policies in two disparate areas. One policy area is reflected in the Government's commitment to assist older people, whether they are active, early retirees or the frail elderly, wealthy or poor, to live in their chosen place of residence. Increasingly this chosen place of residence may be a small, medium density dwelling. The other policy area is that related to reducing energy consumption in buildings. This policy is reflected in recently proclaimed building regulations aimed at reducing space heating/cooling requirements in housing. The building regulations include details of acceptable construction practice for energy efficiency that may not be appropriate in small, medium density housing. It was proposed in this thesis that extensive use of space heating and cooling in housing for the aged was required because well-established benchmarks for energy efficient design in a temperate climate were not generally appropriate in small, medium density dwellings and were particularly inappropriate in housing for the aged. `Appropriate' in this context referred to: indoor temperatures being acceptable without the need for space heating and cooling; retaining the site planning and general form of typical, medium density aged persons housing developments in suburban Australia; cost effectiveness over the life of a building; and fitting the needs of physically and financially vulnerable older people. / The methods used to examine the notion of appropriateness commenced with a literature review that related to the general physical and economic status of older people and their needs and responses to space heating and cooling in the home. Further, the literature review considered the principles of energy efficient design and benchmark criteria for energy efficiency. Arising from the literature review, two tools of study were used in order to develop a set of data encapsulating the salient features of small, medium density housing. The first was a multiple case study of typical housing for the aged. This was conceived as a way of determining if small, medium density dwellings could provide appropriate indoor thermal conditions and/or were designed to be energy efficient. The indoor temperatures were monitored in summer and winter and annual energy consumption was established and statistically analysed. The building designs were analysed in terms of their orientation, glazing areas, wall areas, volumes of thermal mass and ventilation capacity and compared with benchmarks for energy efficient design. The second tool involved a series of computer simulations of a typical small, medium density dwelling. The simulation process was utilised to determine if a new set of benchmarks for energy efficient small, medium density dwellings were required that would incorporate the notion of appropriateness. From the multiple case study it was found that, irrespective of design, indoor temperatures in 98% of dwellings were above the acceptable maximum summer temperature of 27.4°C in still air and indoor temperatures in all dwellings were found to be below the acceptable minimum daytime temperature of 19.8°C. / The findings also showed that some aspects of the benchmarks for energy efficient design were not appropriate in typical, medium density housing constructed specifically for the aged. From the simulation process it was discovered that acceptable temperatures could be achieved in small medium density housing if the principles of energy efficient design, incorporated within a new set of benchmarks, were integrated with appropriateness criteria for housing for the aged. The approach taken with the new benchmarks was to create both performance based and prescriptive design solutions. The performance model differs from the current benchmarks for energy efficient design in that it establishes key functional objectives for energy efficient design. Compared to the current benchmarks, the prescriptive design solutions show significant reductions in the areas of northerly glazing and total glazing. To compensate for the reduced area of northerly glazing, both direct and indirect means of solar gain are utilised for passive heating. The thesis outcomes have implications for three areas of the construction industry. The prescriptive design solutions presented in building regulations for energy efficiency in housing need to be qualified, the design briefs prepared for energy efficient construction of small, medium density housing need amendment and the approach taken by designers involved in energy efficient small, medium density housing needs to be reconsidered.