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Estimating Silvicultural Treatment Response Utilizing a Six Meter Height-Intercept Approach
No full textManaged forests are subjected to wide variety of silvicultural treatments. These treatments or the lack thereof can influence the height growth of young stands. There is no standard approach to evaluating or quantifying the differences between silvicultural treatments. This is especially true with regard to forest models. We utilized a two-point height intercept method at 6 meters as an approach to quantify the treatment response of site preparation and planted versus naturally regenerated on ponderosa pine (Pinus Ponderosa) and western larch (Larix occidentalis) within the Inland Northwest, USA. Sampling was performed utilizing a balanced orthogonal matrix to ensure that sampling was collected across the entire range of climatic and environmental conditions present in the study area. Three geospatially derived variables: Mean Annual Precipitation (MAP), Soil Depth to Restrictive Layer (SDEP), and Annual Growing Season Days (GDAY) greater than 10 degrees Celsius were used to develop the sample matrix. Stand histories were researched and validated with site preparation and planting records. A site-treatment linear regression model was developed for each species after performing step wise model reduction techniques from a larger full multiple regression model. Adjusted R2 for the western larch model was 0.4029, while the adjusted R2 for ponderosa pine was 0.6052. The addition of site preparation treatment before planting did not increase the growth rates of planted western larch. There was a significant increase in growth rates between planted and naturally regenerated western larch and ponderosa pine (Pmasters, M.S., Natural Resources -- University of Idaho - College of Graduate Studies, 2021-0
Resource Constrained Adaptive Evolution of Mollusc Shell Form
No full textAll life has evolved within a set of extrinsic constraints imposed by the environment. Environmental constraints can limit the scope of evolution and distribution of species in predictable ways when taken in the context of intrinsic, genetically coded metabolic mechanisms. For example, species that require a limiting macronutrient for trait synthesis may only express enlarged or elaborate traits in areas or time periods of abundant macronutrient availability. As many functionally important traits for a variety of organisms have been proposed to be modulated by these eco-physiological constraints (EPC), EPCs have been invoked as one of the major driver of historical and contemporary spatial patterns of biodiversity. The study of EPC dynamics entails aspects of physiology, systematics, biogeography, adaptation, and speciation. One approach to characterize how EPCs dynamics may affect diversification is to examine evolutionary and spatial patterns of trait expression in a single system where EPC dynamics are partially understood, and then test for similar spatial/evolutionary patterns across physiologically similar systems. The aim of the present work is to use Mountainsnails (Oreohelix), marine molluscs, and calcium carbonate (CaCO3) availability as a framework to gain a better understanding of how EPC dynamics may affect diversification and species distributions. First, I conducted phylogenetic analyses of Oreohelix to examine how species limits are associated with the evolution of a resource-intensive trait (calcareous shell ornaments). I found that ornamented Oreohelix have evolved recently and that ornamentation is not associated with delimited species units. Second, I utilized species distribution models and shell biometrics to examine whether ornamented Oreohelix are associated with calcareous bedrock and if ornamentation confers greater shell strength. I show that ornamented Oreohelix are generally restricted to calcareous rock environments and stronger than smooth Oreohelix save those smooth forms sampled from calcareous environments. Third, I extend the CaCO3 EPC framework to all marine molluscs and ask whether ornamented marine molluscs are restricted to regions of greater CaCO3 availability and if they will be more greatly affected by future ocean acidification compared to smooth or sea slug molluscs. Ornamented molluscs were found at higher frequency in CaCO3 environments but were shown to be less affected by future anthropogenic ocean acidification compared to smooth forms which are commonly expressed at higher latitudes.doctoral, Ph.D., Bioinformatics & Computational Biology -- University of Idaho - College of Graduate Studies, 2021-0
Understanding agricultural perspectives of cover crop adoption and symbols of good farming in the inland Pacific Northwest
No full textGlobally, there is increased awareness of the environmental consequences of conventional agriculture and the need for viable economic and environmental options for farmers. In response to these problems, there has been increased funding and promotion at the national and regional level for conservation practices like cover crops and conservation tillage. Cover crops and conservation tillage can reduce erosion, improve soil and water quality, increase water holding capacity, and improve farming efficiency and productivity. Adoption of such practices varies widely across the nation; thus, research calls for a better understanding of how to support and sustain farmers’ adoption of these practices. The two chapters of this thesis draw semi-structured interviews (n=28) and focus groups (n=61) with crop and livestock farmers across the dryland, wheat-growing region of the inland Pacific Northwest (PNW). For chapter 1, we draw from the diffusion of innovations theory to better understand farmers’ perspectives on the perceived relative advantage (the degree to which an innovation is compatible with the current system) and trialability (how easily potential adopters can try an innovation) of cover crops. For chapter 2, we draw from the ‘good farmer’ literature, grounded in Bourdieu’s theory on field, habitus, and capital to understand the extent to which engagement with conservation tillage (CT) systems reinforce symbols of good farming and bolsters farmers’ engagement to stewardship behavior. We find that cover crops are associated with perceptions of low relative advantage and low trialability. However, results from chapter two suggest that engagement with CT systems allows farmers to demonstrate productivisit symbols of good farming, while bolstering their engagement with stewardship behavior. Implications from this thesis can better inform regional conservation strategies that improve agronomic and economic outcomes for farmers across the PNW.masters, M.S., Natural Resources -- University of Idaho - College of Graduate Studies, 2020-0
High-Frequency GaN-Based Inverter Control Design Using PSIM
No full textGallium nitride (GaN) transistors are becoming more common in power electronics. This thesis describes how they can be used to improve solar generators by improving the inverter that they contain. The benefits of using GaN in an inverter include higher efficiency, higher switching speeds, and the ability to reduce the size of some inverter components. The full-bridge inverter topology was chosen for this inverter because of its favorable high-frequency switching characteristics. Using a full-bridge GaN-based inverter evaluation board from Transphorm, Inc., a PI control scheme was successfully designed for this inverter using the simulation software PSIM. This control scheme performed satisfactorily when tested in the inverter showing that PSIM can be a useful design tool for high-frequency GaN-based inverters.masters, M.S., Electrical and Computer Engineering -- University of Idaho - College of Graduate Studies, 2020-0
Evaluating swimming behavior and performance of upstream migrating Pacific lamprey using experimental flumes and accelerometer biotelemetry
No full textStream connectivity is necessary for the persistence and viability of migratory fish populations. However, many of the world’s river contain dams, creating barriers or obstacles that can impede movement. Fishways have been constructed to provide passage for migratory fishes, but traditional designs were largely incorporated for fish with strong burst swimming capabilities, such as subcarangiform swimming salmonids, and do not consider species with alternate swimming modes (i.e anguilliform). Additionally, high velocities and turbulent conditions within fishways can force fish to swim at prolonged swimming speeds, potentially resulting in fatigue or delayed passage. The Federal Columbia River Power System (FCRPS) has served as a model system for fish passage designs worldwide. In particular, Bonneville dam, the lowermost dam on the Columbia River, is a complex comprised of three channels separated by islands and has two primary fishways. Each fishway begins with low gradient collection sections that lead to steeper pool and weir ladders, and then transition to vertical slot weirs before exiting into the forebay. It provides passage for a multitude of species, though passage rates are low for several species including Pacific lamprey (Entosphenus tridentatus; ~50% passage rate). Previous research has revealed approximately one quarter to one third of lampreys that reach the serpentine weir section of both fishways fail to pass the dam. Past studies have demonstrated that lamprey can pass single, high velocity vertical slot weir. We hypothesized fatigue may occur during passage of the 12 weirs present in the serpentine weir section and tested this hypothesis using experimental behavioral observations and a novel application of acceleration biotelemetry in at-liberty animals. We manipulated exercise histories of adult Pacific lamprey prior to a weir passage challenge in an experimental flume (11.6-m long × 1.2-m wide × 2.4-m high). Treatments were applied using a 2 × 2 factorial design with two exercise velocities (1.0 m/s and 1.4 m/s) and two exercise durations (1 x 20 min and 2 x 20 min with a 10 min recovery interval) in addition to an unexercised control prior to a high velocity passage challenge at a single vertical slot weir. The results indicate that the exercise history of lamprey and encountered water velocity affect passage success. In the experimental flume experiment, lamprey passage success was lowest (53%) during the high-velocity, long-duration treatment as compared to the control (89%) (2 = 22.3, P < 0.001). Dorsal distance, after accounting for body length, was the only morphological covariate associated with passage success; dorsal distance increased the odds of successful passage. We used accelerometer biotelemetry to identify activity and behavioral responses of adult Pacific lamprey to local passage conditions at a previously identified passage bottleneck (the upper Washington-shore fishway of Bonneville Dam), with an emphasis on the serpentine weir section. Accelerometer biotelemetry results revealed that lamprey exhibited high intraspecific variability in duration and timing of attached and burst movements among sections of the fishway. Within the serpentine weirs, lamprey that were successful at passing spent more time bursting compared to lamprey that did not pass. Unsuccessful fish spent a longer duration attached and had higher turn-around rates, leading to longer residence times when attempting to pass. There was not clear evidence of gradual fatigue associated with non-passage, suggesting threshold changes in behavior or motivation. Collectively, these results reveal that cumulative effects of passage are important to consider when designing or evaluating fishways. Velocities that require high activity levels over a prolonged period of time may induce fatigue, indicating the need for refuge areas to allow recovery.masters, M.S., Natural Resources -- University of Idaho - College of Graduate Studies, 2020-0
Effect of Revisit Frequency and Availability of Cloud-Free Observation on Landsat Global Burned Area Mapping
No full textFire is one of the most relevant disturbances affecting terrestrial ecosystems globally, altering vegetation, soil, water, and atmospheric composition. Fire causes a non-permanent land cover change, through the removal of vegetation, the deposition of charcoal and ashes, and the exposure of soil; the temporal persistence of these changes is highly variable, ranging from a few weeks in tropical savannas to years in boreal forests. Global burned area products have been systematically generated in the past 20 years from several coarse spatial resolution (250 m - 1 km) Earth Observation (EO) systems. These products are the main input in global biomass burning atmospheric emission inventories, and in the most recent studies on the role of fire in the global carbon cycle and vegetation dynamics. Because of the non-permanent nature of burned areas, the algorithms employed for the generation of global burned area products rely on the availability of daily or near-daily observations from coarse resolution EO systems. The high revisit frequency ensures that a sufficient number of cloud-free observations are generally available globally before burned areas disappear, with few exceptions in known locations of persistent cloud cover. The systematic generation of moderate spatial resolution (10 m - 30 m) burned area products could potentially meet the needs of a variety of fire science and applications communities, and at different scales from global (e.g., pyrogenic carbon emissions estimation) to regional scale (e.g., environmental post-fire assessment and remediation decision support). Algorithms for the generation of moderate resolution burned area maps have been recently prototyped regionally and continentally, and have the potential for global implementation. However, ,moderate resolution sensors have reduced temporal resolution (e.g., 16 days for Landsat) compared to coarse resolution sensors (e.g., ~1 day for MODIS), which could potentially lead to omission errors in ecosystems where the spectral signal associated with burning events disappears quickly, and cloud cover limits the number of valid observations. My dissertation focuses on estimating the combined effect of the impermanent nature of land cover change typical of burning events and the cloud cover, which reduces the number of valid observations available to detect burns, on global burned area mapping using Landsat data. The dissertation has three objectives. The first objective (Chapter 2) is to estimate the temporal persistence time of the signal associated with burned areas, stratified by ecosystem and land cover type, making use of the global, multiyear MODIS data record. The second objective (Chapter 3) is to evaluate the suitability of the MODIS-derived cloud mask as a proxy for Landsat 7 cloud observations. Finally, the third objective (Chapter 4) is to estimate the potential omission errors in a hypothetical global Landsat burned area product, due to the combined effect of reduced revisit frequency and cloud contamination. Chapter 2 presents a global analysis of the burned area persistence time defined as the duration of the spectral separability of the burned / unburned areas mapped by the MODIS Global Burned Area Product (MCD64). The separability was computed by analyzing time series of normalized burn ratio (NBR) from nadir BRDF-adjusted MODIS reflectances (MCD43). Results showed that, globally, the median burned area persistence time was estimated as 29 days and 86.6% of the global area, as detected by MODIS, can be detected accurately only for up to 48 days. Furthermore, the results indicated that early and late fires had a shorter persistence time compared to fires burning in the central portion of the fire season. The results, therefore, indicate that the persistence time can be a limiting factor for mapping burned areas using moderate resolution satellite sensors, which have a low temporal resolution (e.g. Landsat 16 days, Sentinel 2A and 2B 10 days each, 5 days when used in combination). Chapter 3 presents a comparison of Landsat and MODIS cloud data. Landsat 7 Enhanced Thematic Mapper Plus (ETM+) image cloud fractions over land were compared with collocated MODIS cloud fractions, generated by combining the MODIS-Terra global daily cloud mask product (MOD35) with the Landsat 7 ETM+ image footprints and acquisition calendar. The results showed high correlation between the MODIS and Landsat 7 ETM+ cloud fractions (R2 = 0.83), negligible bias (median difference: < 0.01) and low dispersion around the median (inter-quartile range: [-0.02, 0.06]). These results indicated that, globally, the cloud cover detected by MODIS Terra data can be used as a proxy for Landsat 7 ETM+ cloud cover at the Landsat World Reference System (WRS) scale. Chapter 4 builds on the previous chapters and presents the potential omission error of a hypothetical Landsat global burned area product compared to the MODIS global burned area product. The Landsat omission error was estimated as the amount of burned area detected by MODIS that would not be detected by Landsat 7 because of the combined effect of the impermanent spectral signal associated with burned areas and missing observations due to cloud cover. The simulation was informed by the MODIS global burned area product (MCD64A1), used as fire mask to define the location and timing of burning, and the MODIS-Terra cloud product (MOD35), used to determine the number of post-fire cloud-free observations available following the Landsat 7 acquisition calendar and ground swath footprints. Globally, the resulting omission error was estimated as 19% of the average annual burned area detected by MODIS, with a maximum error over forest land cover (33%) and minimum over shrubland land cover (5%). The results were derived using the acquisition calendar of Landsat 7 only, however, thanks to the aggregation of data from over 15 years of acquisitions, the results can be extended to the other existing Landsat sensors, which are positioned on the same orbit shifted by an 8-days lag, and also to Landsat 9, which is planned to be launched in the same orbit of Landsat 7 by Spring 2021. The findings of this research have implications for the future development of a global burned area product generated using moderate resolution EO data such as Landsat. The burned area persistence times provide an estimation of the period after the burning date in which burned areas can be mapped reliably and have implications on the length of the rolling periods, used in change detection algorithms to map burned areas. The potential omission error of a Landsat burned area product identified locations and times of the year in which the low revisit frequency of Landsat combined with the occurrence of clouds can have degrading effects on Landsat burned area maps accuracy.doctoral, Ph.D., Natural Resources -- University of Idaho - College of Graduate Studies, 2020-0
The Security and Performance Impact of Object File Shuffling
No full textSoftware running on desktop computers, laptops, and servers can be updated on a regular basis, installing security and bug fixes. However, industrial control system devices and embedded devices are often deployed and then left in operation for long periods of time with no software updates. The software running in these devices is often installed as an integral part of the system, and is typically called firmware. As these devices age, many have security vulnerabilities found that are located in their firmware or related libraries and as such need to be patched to mitigate the vulnerability, or they are otherwise vulnerable to exploitation. One issue with updating this firmware is that the original image may contain an old version of a library that they rely on for their processes and haphazardly updating may break that functionality. Also, updates may cause changes in critical real-time behavior of the systems. If the firmware is not updated, attacks that exploit discovered vulnerabilities can be successful against all of the deployed devices. This research explores diversification of deployed firmware through the use of shuffling portions of the firmware's code while retaining original functionality. This thesis examines the security impact of shuffling and then reports on a set of experiments that look at performance impact of the shuffling. Results indicate that shuffling can improve security against many modern low-level attacks, and that rearranging the code can change run-time performance of the program by a couple percentage points. With increased security and little performance impact, we recommend further study into the use of shuffling as an added security mechanism.masters, M.S., Computer Science -- University of Idaho - College of Graduate Studies, 2020-0
Investigating the Relationships Among Self-Reported Carotenoid Intakes, Skin Carotenoid Concentrations and Cognitive Outcomes in Early Adolescents
No full textLutein and zeaxanthin are two carotenoids, known as the xanthophylls, which have recently garnered attention for their potential role in cognition. Within the brain, the xanthophylls are believed to be protective via their action as antioxidants. Previous research has indicated possible correlations between serum and macular carotenoid concentrations and cognitive outcomes, but results are generally mixed, particularly when referring to specific aspects of cognition. Measurement of carotenoids via resonance Raman spectroscopy of the skin is reliable, non-invasive and requires minimal training, but there is limited research examining the direct relationship between skin carotenoid concentrations and measures of cognition. Additional insight is needed on the nature of these associations in younger populations. The purpose of this research was to investigate the relationships among self-reported carotenoid intake, skin carotenoid concentrations and cognitive outcomes in early adolescents. Thirty adolescents aged 11-14 years participated in the cross-sectional study. Dietary intake of lutein and zeaxanthin, lycopene, alpha and beta-carotene, cryptoxanthin, total carotenoids, and total fruits and vegetables were assessed from three days of 24-hour dietary recall data collected and analyzed using the Automated Self-Administered 24-hour (ASA24) Dietary Assessment Tool, developed by the National Cancer Institute. Skin carotenoid concentrations were measured by resonance Raman spectroscopy. Assessments from the NIH Toolbox for Assessment of Neurological and Behavioral Function were administered to determine scores of executive function, episodic memory, working memory, attention, processing speed, and fluid cognition, all adjusted for age, gender, race, ethnicity, and parent education. Data analysis was conducted using SAS software and a significance value of p≤0.05. Pearson correlations were used to evaluate the relationship between variables with a normal distribution and Spearman correlations were used between variables not exhibiting characteristics of normality. No significant relationships were found between skin carotenoid concentrations and intakes of carotenoids, including lutein and zeaxanthin. A significant positive association was found between skin carotenoid concentrations and scores of working memory (R2 = 0.43, p=0.02). A significant inverse relationship was noted between intakes of lutein and zeaxanthin and scores of working memory (R2 = -0.43, p=0.02) and significant positive correlations were found between scores of episodic memory and intakes of cryptoxanthin (R2 = 0.41, p=0.02), lycopene (R2 = 0.40, p=0.03), total carotenoids (R2 = 0.39, p=0.03), and total fruit and vegetable intake (R2 = 0.38, p=0.04). Overall, skin carotenoid concentrations were positively associated with scores of working memory. Dietary intake of lutein and zeaxanthin was negatively associated with working memory scores and intakes of cryptoxanthin, lycopene, and total carotenoids were positively associated with episodic memory scores in adolescents aged 11-14 years. Dietary intake of specific carotenoids may have varied associations with specific domains of cognition. Larger sample sizes are needed to comprehensively evaluate these relationships in adolescent populations.masters, M.S., Family and Consumer Sciences -- University of Idaho - College of Graduate Studies, 2020-0
Detection of Terracettes in Semi-Arid Rangelands Using Fourier-Based Image Analysis of Very High-Resolution Satellite Imagery
No full textTerracettes, a step-like microtopographic feature primarily caused by livestock hoof action and grazing on hillslopes, are found throughout semi-arid rangelands of the United States. They have been shown to alter soil moisture, sediment transport, infiltration rates, and coincident vegetation patterns. The spatial extent of terracettes is currently unknown and therefore their landscape-scale hydrologic influence is absent in modeling and land management decision making. When viewed in very high-resolution satellite imagery, terracettes appear as repetitious parallel lines within a specific frequency range. Here, we use frequency-based image analysis via the 2D Discrete Fourier Transform to detect terracettes based on their distinct patterning and orientation. An automated workflow was created to detect terracettes using freely available software and satellite imagery. Results show a detection accuracy of 77%.masters, M.S., Water Resources -- University of Idaho - College of Graduate Studies, 2020-0
Fundamental Limits of Multiuser Optical Wireless Communications With and Without Secrecy Constraints
No full textOptical wireless communications (OWC) has recently gained a lot of interest among industrial and academic communities. The main inhibitor factor of this resurgence of interest is the fact that radio-frequency (RF) spectrum is already so densely occupied to handle the increasingly high demand, and hence, exploring higher frequency spectrum, including the optical range, would be a relief. Another reason behind such an interest resides in the relatively simple deployment of OWC systems. However, before a real deployment of OWC systems, there is a persistent need to establish its fundamental performance limits (e.g. capacity, secrecy capacity, and capacity region) and extract design guidelines for building efficient, reliable, and secure OWC systems. Indeed, due to different propagation channels and different transmit constraints, RF communications and OWC are fundamentally quite different. For instance, the popular intensity modulation and direct detection (IM-DD), which is a favorable scheme for OWC due to its simplicity, has some subtle differences in comparison with RF systems manifested in the nonnegativity of the transmit signal, in addition to constraints on the peak- and average-intensity of the signal. These, in turn, make the fundamental performance limits and the optimal transmission schemes for OWC based on IM-DD different from those for RF systems. Since the fundamental performance limits of OWC play a vital role in extracting guidelines and communication protocols for designing reliable and secure systems, this dissertation addresses those limits in an OWC setting. Particularly, this dissertation presents novel contributions to the understanding of the fundamental limits of multiuser OWC with and without secrecy constraints. When a secrecy constraint is imposed, this dissertation provides analytical results on the characterization of the optimal transmission schemes for secure and reliable OWC when input-dependent Gaussian noise and Poisson noise models are considered. Additionally, an asymptotic analysis of the secrecy capacity (the fundamental performance limit for secure communications) is presented. Furthermore, a two-user optical multiple access channel model, which depicts a multiuser OWC scenario without secrecy constraints, is proposed and the optimal multiuser transmission schemes that achieve the capacity region (fundamental performance limit of this multiuser scenario) are developed. Moreover, the capacity region of the considered optical multiple access channel is explicitly characterized in a closed-form expression in the regime where the peak- and average-intensity constraints are vanishingly small. After establishing the fundamental performance limits of OWC, powerful machine learning techniques, such as deep learning, are employed for the implementation of OWC systems. In particular, a simple and cost-effective learning-based system with (near-)optimal performance is proposed and is implemented by merely taking off-the-shelf deep learning models, applying them to an OWC design problem, and tuning them based on the easily generated training data.doctoral, Ph.D., Electrical and Computer Engineering -- University of Idaho - College of Graduate Studies, 2020-0