The comprehensive, mathematical model SRFR in its zero-inertia form, is utilized here for simulation of flow in slightly-sloping basins using various flow and basin parameters. These parameters are combined in dimensionless form for plotting performance curves pertaining to field slopes ranging from 0 to 0.02%. These show the distribution uniformity (DU) resulting from a particular set of input variables. DU is an important and useful tool for describing the performance of slightly-sloping basins. The DU was found to increase with flow rate and application time but decrease with the increase in infiltration rate, length of run and roughness coefficient. Increase in slope does not affect DU for the highK*, but for low K* can yield DU either increasing or decreasing, based on the downstream conditions of the basin. For medium K* and where a downstream stagnant pool of water is absent, increase in slope increases DU.

This thesis discusses a novel hybrid optical LiDAR architecture that employs Texas Instruments’ Digital Micromirror Devices (DMDs) for coarse beam and image steering, a Phase Light Modulator (PLM) for fine field of view steering in a Time-of-Flight (ToF) solid-state LiDAR with contiguous panoramic LiDAR scanning and higher resolution imaging.By synchronizing the laser pulse to the dynamic tilt movement of the micromirrors on the DMD, a blazed grating condition can be satisfied, and light is diffracted and steered into one of the several diffraction orders with high diffraction efficiency. By employing Computer Generated Holograms (CGHs) on the PLM, the micro-mirrors’ height on the PLM can be modulated based on the hologram’s parameters, and a variety of grating patterns can be created for controlled image and/or field of view steering. There are multiple hierarchies of FoVs in this paper. For simplicity, the system’s total field of view is defined as the FOV of the system, the subdivisions of FOVs from the diffractive beam steering by DMDs are termed as ‘Sub-FOV’, and the finer FOVs within the sub-FOV of the DMD are termed as ‘Sub-Sub-FOV’. The proposed DMD-PLM Hybridized scanning and solid-state flash LiDAR architecture utilizes a near-infrared nanosecond pulsed laser, two synchronized DMDs (one for ‘Transmitter’ and the other for ‘Receiver’) for coarse sub-FOV beam steering, a PLM for finer sub-sub-FOV steering, and a Multi-Pixel Photon Counter (MPPC) to capture two-dimensional ToF LiDAR images. The experimental results demonstrate that the proposed LiDAR architecture increases the effective pixel count by 9-fold in a single sub-FOV by employing PLM sub-sub-FOV steering. There are seven diffraction orders from the DMDs used for coarse steering in the experiment, and each DMD order’s sub-FOV carries 9 sub-sub-FOVs from the PLM fine steering. Therefore, there is a 9-fold increase in the effective pixel count of the original LiDAR architecture, which only employed DMDs for the beam and image steering [2]. An addition of a holographic-based FOV steering PLM increases the pixel resolution by multiple folds in the LiDAR imaging by fine steering into the sub-FOV regions. With advantages, there exist some challenges in this hybrid LiDAR as well. There is the presence of the strong specular reflections at the 0th order due to the cover glass reflection from both the DMDs and PLM, as well as PLM’s 0th order interference with its higher orders from PLM’s MEMS mirror due to non-linearity and truncated phase modulation in the infrared region. The protective cover glass layer of both the DMDs and PLM is VIS/UV coated but not coated for infrared, causing strong Fresnel reflection at the 0th order. This unmodulated reflection introduces crosstalk between the 0th order and higher orders, making it difficult to distinguish higher-order diffraction images from the zeroth-order image. To mitigate this issue, a physical Fourier mask is applied to block the cover glass reflection from the transmitter-DMD, while a polarization-selective Fourier filtering technique is used to suppress the PLM’s cover-glass reflection and its zeroth order. This thesis presents a further advancement in the hybridized scanning and flash LiDAR architecture described by Chan (2023) [2]. The proposed new architecture enables an n²-fold enhancement in pixel resolution over Chan’s architecture of DMD-only based LiDAR by employing phase modulation with a PLM to perform sub-sub-FOV steering within each DMD’s sub-FOV. Along with the pixel resolution enhancement, this new architecture addresses the crosstalk issues caused by the cover glass specular reflection, beam spilling on adjacent orders, and gaps in beam steering and LiDAR imaging, utilizing a paraxial raytrace model for illumination design of the transmitter and contiguous receiver FOV design. Both the theoretical formulation and experimental validation of the resolution enhancement mechanism are provided. The crosstalk suppression techniques are effectively handled using Fourier-domain masking for DMD’s cover-glass reflection and polarization-selective filtering for the PLM’s cover glass and 0th order. The system is further supported by an analytical first-order model for contiguous, gap-free LiDAR imaging, and also demonstrates foveated scanning capabilities. These advancements offer significant potential for high-resolution, compact, and adaptive LiDAR systems in applications such as autonomous driving, robotics, and 3D mapping.

Diffuse traumatic brain injury (TBI) represents the most common form of brain injury, yet conventional magnetic resonance imaging (MRI) fails to detect neuroinflammatory pathophysiology without overt structural abnormalities. Diffusion MRI (dMRI) offers sensitivity to microscale pathophysiological changes, but imaging signatures, characteristic patterns on scans, require validation against histopathological markers. This study established radiologic-pathologic correspondence between dMRI signatures and histopathologic targets in experimental diffuse TBI. Ex vivo dMRI was performed on adult Sprague Dawley rats (n = 4) 7 days post-injury using a 7T system with mean apparent propagator metrics including Return-to-Axis Probability (RTAP) and Return-to-Origin Probability (RTOP). Immunohistochemical analysis used markers for microglia (Iba1+, CD83), astrocytes (GFAP, AQP4), and neuronal integrity (MAP2). Receiver operating characteristic (ROC) analysis evaluated the diagnostic performance of each marker using skeleton analysis protocols. Quantitative morphological analysis compared the primary somatosensory barrel field cortex (S1BF) and the motor cortex (control). Spatial correspondence was established between dMRI hyperintensity in RTAP and RTOP maps, where qualitative analysis identified high concentrations of microglial (Iba1+) pathology in the S1BF. Iba1+ quantitative analysis revealed significantly lower microglial endpoints and higher process length in S1BF regions compared to motor cortex, representative of injured pathology. CD83 showed contrasting endpoint patterns to Iba1+ but similar process length increase, providing complementary validation of microglial activation. CD83 endpoints demonstrated the strongest diagnostic performance (AUC = 0.750), while Iba1+ endpoints revealed an inverse relationship requiring reinterpretation (AUC = 0.816). GFAP, AQP4, and MAP2 showed minimal regional differences and poor diagnostic performance, suggesting limited utility as biomarkers at this timepoint. Imaging confusion matrix analysis demonstrated perfect specificity in control regions but limited sensitivity (33.3%) in injury regions. This study provides verification of radiologic-pathologic correspondence between dMRI signatures and microglial activation in experimental diffuse TBI.

Background: Previous work showed that electrically-evoked inhibition to Rod Bipolar Cells (RBC) is reduced in a mouse model of early diabetes. It is hypothesized that this is due to impaired Ca2+ handling in the presynaptic amacrine cell, either through increased Ca2+ buffering or decreased influx. To test this hypothesis and develop a mechanism for this effect, a model where direct optogenetic activation of inhibitory amacrine cells that expressed the light-activated channel ChR2 was used to isolate amacrine cell inputs to RBCs. Application of selective Ca2+ channel blockers could then assess potential locations of amacrine Ca2+ disruption. Using whole cell patch clamp electrophysiology, recordings were made from a 6 week diabetic population and vehicle injected control animals. Results: Robust inhibitory currents were recorded from RBCs after ChR2 stimulus that were significantly diminished by the application of nifedipine to block L-type Ca2+ channels in both diabetic and control conditions. There were no significant differences in the magnitude of these responses between conditional groups. However, in the control group the decay tau of the response to the 50ms stimulus was significantly diminished by nifedipine (? p =0.0498, n = 5), but this was not seen in the diabetic group (? p = 0.9498, n=7). A 1s nifedipine-reduced response saw its decay tau increase in the diabetic group but not the control. Ca2+ - induced Ca2+ release (CICR) blockade with ryanodine decreased responsivity equally between groups in the 1s stimulus, but showed no significant kinetic changes. CICR blockade for a 50ms stimulus response showed significant kinetic changes in diabetes, but otherwise reduced the response equally between diabetic and control. Blockade of the mitochondrial Ca2+ uniporter (MCU) had little effect on the optogenetic response. Conclusion: This study presents evidence that diabetes alters amacrine cell output to the rod bipolar cell unmasked through blockade of the L-type calcium channel, and the Endoplasmic Reticulum (ER). An apparent explanation for our results is that diabetic calcium buffering is dysregulated, leading to prolonged responses. The underlying mechanism for this alteration is complex and not yet clearly elucidated. Significance: Using optogenetic isolation of amacrine to RBC inputs, we show nifedipine unmasks slower decay kinetics (1s), and delayed onset in diabetes at 50ms, that ryanodine blockade modulates kinetics in control, but not diabetic (50ms), while MCU blockade has minimal effect.

Primary hyperparathyroidism (PHPT) is a common endocrine disorder characterized by increased levels of serum calcium and parathyroid hormone. Although frequently sporadic, a genetic etiology can be confirmed, usually through multi-gene panels, by the identification of germline pathogenic or likely pathogenic variants (GPVs) in at least ten genes in 10-30% of PHPT cases, with important implications for management. Recently published expert guidelines by the American Society for Bone and Mineral Research (ASBMR) recommend genetic testing for patients with PHPT who are under the age of 30, have multiglandular involvement, and/or a family history of hypercalcemia or a PHPT-related condition. We reviewed the medical records of 31 unrelated patients referred for a genetic evaluation for PHPT to calculate the diagnostic rate of testing and compare the phenotypes of patients by testing outcome. The diagnostic rate of genetic testing in patients with PHPT in this study was similar to other rates reported in the literature. As expected, six out of seven individuals with positive genetic testing results were found to meet ASBMR criteria. Importantly, exome sequencing (ES) performed in individuals identified to have an atypical phenotype identified GPVs in genes not included in PHPT multi-gene panels, which was the most common testing modality. These results highlight the utility of genetic testing in patients with PHPT and the role of ES in patients with atypical phenotypic presentations. Larger studies will be beneficial to further investigate the utility of ES in these disorders.

Food security exists when " all people, at all times, have physical and economic access to sufficient, safe, and nutritious food to meet their dietary needs and food preferences for an active and healthy life"(FAO 1996, p.1083). Achieving Sustainable food security in Sub-Saharan Africa (SSA) could be quite a challenge to the ultimate objective of a "hunger free" World. Food security is certainly one of the most complex and multi-dimensional issues of our times in the region, and it is an important measure of development. The general topic of this thesis is the measurement of food security. The general question this thesis asks is: if we include both diet quantity and diet quality in a set of food security indicators, what difference does it make for targeting food-insecure populations and the types of policies needed to reduce food insecurity? Specifically, this thesis investigates two indicators of food security using data from national Household Expenditure Surveys (HESs) conducted in three Sub-Saharan Africa countries in the late 1990s: Ghana, Malawi and Uganda. The two indicators are: household calorie availability, a measure of the quantity of food people eat, and diet diversity, a measure of the quality of that food. Two questions are explored: (1) Do the indicators tell us different things about who in a population is food insecure and the prevalence of food insecurity? And (2) Do they have different determinants? To answer the first question, correlation analysis and contingency tables are employed. To answer the second, community fixed-effects regression analysis (Ordinary Least Squares and Two-stage Least Squares) is employed.

Since precipitation is a crucial component for forage production in the southeastern rangelands of Arizona, ranching operations m this region are highly vulnerable to fluctuations in climate patterns. If crude ENSO forecasts are the only type of climate information available to a rancher, can this information improve resource management strategies and influence the stocking decision? The stocking decision is modeled for the San Carlos cow-calf ranching operation through a stylized dynamic stochastic framework utilizing El Nino Southern Oscillation (ENSO) forecasts that represent qualitatively different types of climate activity such as El Nino and La Nina events to determine the value of climate forecast information in the range cattle stocking decision. ENSO forecasts can lead to improved ranch profits as well as lower average stocking rates.

Existing literature analyzing consumer demand for organically grown produce has primarily consisted of studies that contain self- reported data from a specific region in the US. Research utilizing direct purchasing behavior of organic produce at the household level is almost non-existent. With the use of ACNielsen household scanner data, consumer demand and loyalty to organic fresh products are analyzed as a function of own price, income, conventional prices, household composition, and demographic attributes. While organic products still maintain a small market share in the produce industry, an empirical model must correctly account for corner solutions where a high percentage of households choose conventional over organic items. In controlling for unobserved heterogeneity of households in a panel model, empirical estimates suggest that price effects, the presence of adolescent children, larger households, income levels, and female head of household demographics are statistically significant influences on organic produce purchase decisions at the household level.

This study examines diffusion of Bt cotton in 27 U.S. cotton-producing regions from 1996 to 1999. First, a dynamic logistic diffusion function is estimated to explain regional differences in both the rate and extent of Bt cotton adoption. The function's flexible specification allows for accelerated adoption as well as deadoption. Second, a pesticide use equation is estimated to test whether or not Bt cotton has reduced traditional pesticide use. The two equations are estimated independently and then as part of a simultaneous system to account for potential endogeneity of Bt adoption in the pesticide use equation. Results suggest that demand-side factors, such as pest damage, input costs, output price and government policy significantly influence diffusion, as do supply-side constraints on Bt seed variety availability. The hypothesis that use of Bt cotton does not reduce the use of traditional pesticides is solidly rejected in all of the econometric specifications tested. Results concerning farmers' overall costs, however, are more ambiguous. Estimates suggest that, in many regions, overall costs have not decreased and in several regions, may have increased, Cost-savings alone may not explain the widespread adoption of Bt cotton. Future research on the impacts of Bt cotton on yields would be useful.