79717 research outputs found
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Before-after-control-impact study reveals muted avian response to low-severity wildfire
No full textWildfire is increasing in frequency and severity across the western United States, highlighting a need to understand how biological communities are responding to this disturbance. Bird communities are useful indicators of ecological change as they are relatively easy to survey and are a well-studied taxonomic group in terms of behavior and life history. I utilized a before-after-control-impact study design to test three hypotheses regarding bird response to wildfire in the mixed-conifer forests of the H.J. Andrews Experimental Forest, Blue River, Oregon following the Holiday Farm Fire of 2020. The Vegetation Selection Hypothesis states that after fire, birds will move to forests that most closely resemble their preferred seral stage; the Site Fidelity Hypothesis states that after fire, birds will return to where they occurred the previous year; and the Concussion Effect Hypothesis states that the landscape effect of fire will lead to birds moving into nearby, unburned habitat. Point count data collected two years prior to the fire and three years after were used to model changes in total abundance for six focal bird species. I did not detect a strong effect of fire on most of the species in my study. However, the Western Flycatcher (Empidonax difficilis) did have abundance changes that showed moderate support for the Concussion Effect Hypothesis Due to the small spatial replication in this study, I recommend further research into bird responses to wildfire using a larger dataset that includes varying fire severity
Wireline Link Architectures for Bandwidth and Noise Limited Channels
No full textCloud computing and AI applications are propelling a surge in the demand for higher data rates in data center. Achieving higher data rates between two nodes without reducing their physical distance has led to higher insertion loss in the communication channel. The higher losses require extensive signal processing and equalization to obtain data with a very low bit error rate, resulting in a significant increase in power consumption. Two research studies are presented to address these challenges: 1) a machine learning inspired wireline transceiver, addressing high channel loss power efficiently and 2) A high-swing PAM-8 voltage-mode transmitter, achieving high data rates with reduced Nyquist loss
Variable-density thinning effect on forest microclimate and growth : a western Oregon case study
No full textClimate change driven droughts and temperature extremes pose mounting challenges to forest growth and resilience in the Pacific Northwest. Variable-density thinning (VDT) has gained traction as a silvicultural strategy to enhance structural complexity, which may buffer forests against climatic stressors. This thesis investigates how post-harvest density gradients—comprising leave islands, thinned matrix, and prescribed gaps—alter microclimatic conditions and modulate the growth of second growth Douglas-fir (Pseudotsuga menziesii) in western Oregon. Additionally, we quantify how air temperature, relative humidity, and soil moisture interact to shape climate-coupled tree growth sensitivity across varying structural and topographic contexts. Thirty Douglas-fir were instrumented across a blocked statistical design at Oregon State University’s Blodgett Research Forest. Continuous measurements of radial stem growth, air temperature, relative humidity, and soil moisture were recorded from May to November 2024. Microclimate responses to treatment and slope aspect were evaluated using autoregressive linear mixed models. Growth dynamics were analyzed using a generalized additive mixed model (GAMM) framework that incorporated smooth functions for environmental variables, random intercepts for individual trees, and an autoregressive temporal structure. Predictive modeling and derived sensitivity metrics were used to evaluate how each treatment-aspect combination modulated growth responses across a range of environmental conditions. Results revealed that VDT treatments produced significant differences in relative humidity and soil moisture but not air temperature. Growth increment varied significantly among treatment-aspect combinations, with Thin-West exhibiting the highest mean growth and Thin-South the lowest. Predictive modeling showed that relative humidity was the most influential microclimatic predictor of growth, followed by soil moisture and air temperature. Growth sensitivity to air temperature, relative humidity, and soil moisture content was highest in dense canopy treatments on southern aspects and lowest in thinned treatments on southern aspects. By integrating microclimate and growth models, this study isolates the mechanisms by which structure-induced environmental changes affect tree growth. The results highlight key trade-offs between resource availability and climatic conditions and suggest that some configurations may sustain growth—or resist tree water deficit—under increased climate variability. This work informs spatially explicit, climate-adaptive silvicultural strategies for managing Douglas-fir forests in the Pacific Northwest
Two Content Analyses of the International Journal of Play in the Areas of Play Therapy Supervision and Qualitative Research on Play Therapy Supervision and Training
No full textThe purpose of this dual manuscript dissertation was to assess the literature published in the International Journal of Play Therapy (IJPT), the flagship journal of the Association for Play Therapy. In manuscript one, we reviewed supervision manuscripts published in the journal on supervision to identify the percentage of supervision domains and play therapy content domains in each manuscript. We identified 13 manuscripts that met our inclusion/exclusion criteria, which identified manuscripts published in the IJPT on supervision. I conducted a content analysis following Schreier’s eight- step process to increase the reliability and validity of the research. A Cohen’s kappa was conducted to assess interrater reliability between coders. I developed a coding template and coding manual. The supervisory relationship and supervisee development each had a presence rating of 92.3%. Supervisor development had a presence rating of 84.6%, and supervision ethics had a presence rating of 69.2%. The other 14 domains held presence ratings between 69.2% and 0%. I identified gaps in the presence of supervision domains in the supervision literature. Manuscript two was a content analysis of trustworthiness strategies used in qualitative research published in the IJPT on play therapy supervision and training. Nine manuscripts on qualitative research in play therapy supervision and training were identified for the content analysis. Twenty-two trustworthiness strategies were identified in the nine manuscripts with triangulation presenting 77.7% of the time and reflexivity present 55.5% of the time. Prolonged engagement and persistent observation, peer debriefing, and member checking were used 3.3% of the time. The average number of trustworthiness strategies per manuscript on qualitative research on play therapy supervision and training published in the IJPT were identified as 2.4. The two studies informed the literature on play therapy supervision to enhance services to play therapy supervises and the clients they serve
Non-Linear Terahertz Pump-Probe Study on the Photoconductivity of Multilayer MoS2
No full textThis thesis investigates the ultrafast photoconductive response of multilayer molybdenum disulfide (MoS2) under high intensity terahertz (THz) excitation. Intense, single cycle THz pulses are generated using optical rectification in a Mg:Li:NbO3 crystal pumped by a fem tosecond Ti:sapphire laser. We then conducted THz pump-probe experiments using optical pump wavelengths of 400nm and 800nm to study carrier dynamics. Time-resolved mea surements reveal that carrier recombination mechanisms may depend on the optical-pump f luence and THz field strength. Optical excitation induces non-linear THz absorption in MoS2, increasing at higher THz field strength. Conductivity and normalized transmittance show that absorption of THz at lower THz frequencies is more pronounce
Blindsight, Visual Indexing, and Bergsonian Perception
No full textThis thesis defends Henri Bergson’s philosophy of memory and encourages the ongoing return to Bergson. I contend that Bergson’s writings have been insufficiently considered in contemporary philosophy of mind and that current work in cognitive science supports significant portions of his Matter and Memory, first published over a century ago. I defend two specific claims which Bergson makes as being empirically plausible and valuable to theoretical efforts. First, I examine Bergson’s argument that, while lesions to the brain might impede their bodily instantiation, memories themselves are not necessarily destroyed by neurological damage. I then consider current blindsight literature, arguing that the interpretation of blindsight as a form of qualitatively degraded consciousness is wholly compatible with Bergson and corroborates this key section of Matter and Memory. Secondly, I examine Bergson’s argument that perception, action, and memory are necessarily unified in their relation to objects of the world in relation to Zenon Pylyshyn’s theory of visual indexing. After considering criticisms of Pylyshyn, I defend a modified theory which aligns with Bergson’s proposal. I conclude that Bergson’s work in Matter and Memory should be considered relevant to ongoing work in the philosophy of mind, particularly in areas of perception and memory.Keywords: Philosophy, blindsight, Henri Bergson, memory, visual indexing, cognitive scienc
Computer science is like a man : the analogical domain as an inclusive pedagogical tool in computer science education
No full textDiversity within computer science education is a persistent problem. Statistics consistently demonstrate the prevalence of a lack of female representation. To address the cascading effects of this issue, inclusivity within educational examples must be considered. Research regarding pedagogical tools highlights the value of using analogy and examples in the classroom environment. Increasing the inclusivity of analogy further impacts the waterfall effect of this problem. Changing the analogical domain of analogy to better reflect the backgrounds of students helps to engage a more diverse population of students and strengthen their ability to connect to course content. This thesis suggests the implementation of the Outlining Programming Analogy Layout (OPAL) framework in facilitating the adaptation of analogical domains to be more inclusive. By using OPAL, it is possible to account for diverse student backgrounds, prior experiences, and knowledge to make the classroom more inclusive to women. Inclusive analogical domain is proposed as the method of building connection between students and dismantling social limitations within the technology industry.Keywords: analogy, pedagogy, computer science education, inclusivity, OPAL framewor
The microclimate of downed wood in mixed conifer forests of western Oregon
No full textDowned wood plays many key roles in forest ecosystems. It provides habitat for diverse organisms and modifies temperature and moisture conditions on the forest floor. As part of a larger project analyzing the relationship between salamanders and downed wood as a post-fire refugia, this study measured downed wood-related microclimate variability at 30 sites along a latitudinal across Oregon. Each site was set up with three pairs of sensors. One sensor in each pair was placed in downed wood and the other in adjacent interspace zones to log temperature and humidity every four hours for a nine-month period. A mixed effects model was used to determine whether minimum, average, or maximum temperature and humidity differed by sensor location, by latitudinal zone ([north, central, south] or the location*zone interaction), or by week of the year or elevation. Weekly average interspace temperature of 12.3oC was observed, slightly higher than the average in-wood temperatures of 11.6oC. Interspace locations experienced weekly maximum temperatures 6.5oC higher and minimum weekly temperatures 3.1oC lower than in-wood sensors across the study. The weekly average interspace relative humidity of 86.2% was much lower than the average in-wood relative humidity of 98.7%, with interspace sensors ranging from 61-98% humidity weekly while the in-wood relative humidity only ranged from 97-99%. Week of the year was one of the key drivers in both relative humidity and temperature, while elevation was only a driver of temperature. The temperature and humidity buffering by downed wood were most prominent in the hotter, drier southern latitudinal zone of the study. The significant temperature and humidity buffering occurring in downed wood of the Western Cascades acts as crucial refugia for climate sensitive species, which should be considered by land managers as they decide what quantities of downed wood should be preserved in our forests.Keywords: Downed Woody Debris, Habitat Ecology, Microclimate Refugia, Post-Fire Refugi
A reverse genetics approach to identify genes affecting H3K27 methylation levels in Fusarium graminearum
No full textHistone H3 lysine 27 trimethylation (H3K27me3) is a conserved chromatin modification involved in reversible gene silencing through the formation of facultative heterochromatin. H3K27me3 is established by Polycomb Repressive Complex 2 (PRC2), a protein complex comprised of the lysine methyltransferase, Kmt6, an allosteric activator, Eed, and a putative targeting protein, Suz12. Although facultative heterochromatin is essential for proper development in many eukaryotes, the mechanisms by which H3K27me3 is distributed and maintained are not well understood. In this study, we sought to identify additional genes involved in the regulation of facultative heterochromatin in the filamentous fungus Fusarium graminearum. Targeted deletion or point mutation of candidate genes revealed a variety of phenotypes, including defects in morphology, asexual reproduction, and secondary metabolism comparable to kmt6 deletion strains. ChIP-seq data determined that proteins encoded by some of these genes impact local, not global, distribution of H3K27me3 and H3K4me2, a histone modification correlated with active transcription. Future work will use RNA isolated from these strains to assess global changes in transcription. This RNA sequencing (RNA-seq) and follow-up studies on phenotypes mentioned above will aid in the understanding of each of these genes in the regulation of transcription by chromatin proteins.Keywords: Epigenetics, Chromatin modification, PRC2, H3K27me3, Gene silencin
Beyond the means : a review of the shortcomings of traditional design processes and a case study on applying inclusive methodologies to an engineering capstone
No full textTraditional engineering and product design processes often fail to address the unique needs of disabled users. Typical methodologies prioritize functional goals and designing for the “average user,” overlooking the emotional and experiential desires of users with disabilities. This thesis dissects and critiques the limitations of traditional processes and explores the benefits of co-creation in design. How designing with, not for, those with disabilities can lead to more inclusive and empowered individuals. In the thesis, a key case study on an adaptive skateboarding system that was developed by an engineering capstone team at OSU-Cascades highlights further the shortcomings of traditional design processes and successful inclusive design methodologies. Robert, a young boy with Cerebral Palsy and a dream to skateboard, was the center of the project. Him and his support team helped guide the team to achieve both functional and emotional goals within the project. Ultimately, this thesis aims to encourage a shift in industry, from designing for disabled users as an afterthought to designing with them in every applicable area.Keywords: Inclusive design, Human-centered Engineering, Adaptive technology, Mechanical Engineering for Accessibilit