1925 research outputs found
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CUDA-DClust+: revisiting early GPU-accelerated DBSCAN clustering designs
No full textDensity-based clustering algorithms are widely used unsupervised data mining techniques to find the clusters of points in dense regions that are separated by low-density regions. This algorithm is inherently sequential and has limitations in its parallel implementation. There have been several parallel algorithms presented in the literature for multi-core CPUs and many-core GPUs. One such algorithm for the GPU is CUDA-DClust. In this paper, we propose a new GPU-accelerated DBSCAN algorithm with several optimizations. In comparison to prior work, our algorithm, CUDA-DClust+: (i) computes the indexing structure on the GPU, (ii) uses kernel fusion to combine the index search and cluster expansion kernels, which reduces communication and synchronization overhead with the host, and (iii) seed list management control is primarily given to the GPU rather than the CPU, which further decreases CPU-GPU communication overhead. We compare our algorithm to three state-of-the-art parallel algorithms in the literature on six real-world datasets. We find that our algorithm achieves a speedup of up to ~23x over the fastest GPU algorithm
Estimating changes in fine-sediment storage at eddy-sandbars on the Colorado River, Grand Canyon, AZ using oblique imagery from remote cameras
Get PDFThis research is a fluvial remote sensing study demonstrating methods for sub-annual monitoring via a dataset containing over 1,000,000 ground-based oblique images that capture daily observations at 43 sandbar monitoring sites in the dam-affected Colorado River in Grand Canyon since 1990. Over half of the world’s major rivers are affected by dams. In many dam-affected rivers, sediment limited conditions have led to increased erosion of banks and fine-sediment deposits for hundreds of kilometers downstream. Quantifying the short-term rates of erosion and measuring the effect of dam operations and beach-building high flows on sediment storage at sub-annual scales is critical to managing downstream resources effectively. Sandbars in the Grand Canyon provide relatively flat, vegetation-free substrates utilized by nearly 25,000 river runners annually. Sandbars are also essential components of riverine systems creating habitat for native fish and storing sediment which would otherwise be transported downstream. This study is the most comprehensive attempt at quantitative analysis of this dataset. I present methods for estimating sandbar volume and hypsometry from the remote imagery. I demonstrate a deep learning approach to semantic segmentation, which allowed for detailed image-derived sandbar area analysis of over 13,000 images across 10 years at three sites. Significant variability was observed in the sub-annual area change due to current dam operations. I determined that erosion, deposition, and the resulting mean monthly area at sandbar sites are more closely correlated with antecedent sandbar size than monthly flow metrics. The analysis of time-lapse videos at 41 sites revealed links between daily and seasonal discharge patterns and mass failure rapid erosion events. These insights increase our understanding of the dynamics of fluvial bedforms in dam-affected, canyon-bound rivers and might improve the adaptive management of the Colorado River in the Grand Canyon. These methods could be applied broadly to remote-camera monitoring efforts in many other fluvial and coastal settings for measuring erosion rates and improving, modeling and sediment budgeting efforts
Interannual xylem plasticity in Pinus edulis and Populus tremuloides
No full textPhenotypic plasticity of xylem conduits could facilitate the rapid acclimatization needed for trees to thrive in the Southwest under the expected increase in drought severity and frequency. This study examined the interannual xylem plasticity of two widespread tree species, Pinus edulis and Populus tremuloides, to better understand it’s role in shaping these species’ response to future climate extremes. We analyzed annual growth rings formed during the years 1995 through 2016 to determine the response of mean lumen diameter and hydraulic mean diameter (HMD) to variation in moisture availability. We hypothesized that lumen diameter changes in size to match environmental conditions, being larger in wetter years and smaller in drier years. We found xylem anatomy was highly plastic with respect to drought but complacent under favorable moisture conditions. Trends in plasticity were consistent among different populations and species. These results suggest that Pinus edulis and Populus tremuloides in the Southwest have limited potential for adjusting xylem conduit size, perhaps indicative of a conservative survival strategy related to the arid climate and frequent occurrence of drought
Variation in morphological, phenological, and physiological traits among southwestern ponderosa pine provenances: insights from field and greenhouse common gardens
Get PDFPonderosa pine (Pinus ponderosa Lawson & C. Lawson var. scopulorum Engelm.) forests of the southwestern U.S. are threatened by climate change. Drought-related tree mortality is already a matter of concern in southwestern ponderosa pine forests and this mortality is expected to intensify over the next century as atmospheric temperature and drought severity increase. In addition, droughts and wildfires have caused a reduction in seedling regeneration and establishment. These recent losses of southwestern ponderosa pine forests may be compensated through artificial regeneration by planting drought tolerant seed sources under increasingly arid conditions. We used field and greenhouse common gardens to investigate provenance variations in survival, growth, budburst phenology, and drought-adapted morphological and physiological traits in ponderosa pines seedlings. Twenty-one provenances from a range of elevations across Arizona and New Mexico were planted in three field common gardens across an elevation gradient: low elevation site in pinyon juniper woodland (1930 m), mid elevation site in ponderosa pine forest (2200 m), and high elevation site in aspen and mixed conifer forest (2780 m). Ten out of the 21 provenances from different elevations were planted in a greenhouse common garden at the Northern Arizona University Greenhouse Facility in Flagstaff, Arizona. We evaluated the overall hypothesis that seedlings traits would vary with provenance environmental characteristics and that low elevation, warmer provenances would have traits more conducive to dry and warm conditions than high elevation, cooler provenances. Results from field common gardens suggest that seedling survival and performance depends on planting location and that low elevation provenances should be considered for planting at trailing-edge and core sites. The importance of biotic agents of seedling mortality increased with elevation of the planting site suggesting that high mortality from biotic agents should be anticipated for plantings at high elevations during assisted migration. Results suggest adaptation of low elevation provenances to warm spring temperatures due to earlier budburst of provenances from low elevations under field and greenhouse conditions. Results from the mid-elevation site suggested a trade-off between growth and water use efficiency under unusually dry conditions. Results from greenhouse common garden suggest: adaptation of low elevation provenances to aridity (as indicated by a lower specific leaf area); faster growth of provenances from wet locations; and greater allocation to roots in western provenances. Such information about environmental and geographical patterns of provenance variation may be useful for developing specific seed transfer guidelines and effective assisted migration strategies to maintain ponderosa pine in a changing climate
A Phenomenological Study of Parental Involvement in COVID-19 Schooling
No full textParental involvement in education is a necessity for student success. Appropriate parental involvement is by nature a subjective concept, and parents, teachers, and school administrators all have their own ideas of what parental involvement includes. But what of parental involvement during the COVID-19 Pandemic? This study was conducted to explore parental involvement in COVID-19 schooling among parents, teachers, and school administrators in a junior high setting of suburban Arizona. The study seeks to understand these stakeholder groups ‘lived experiences’ during the pandemic and their ideas of what parental involvement includes. Participants in this study were taken from three different stakeholder groups at the junior high setting: parents, teachers, and school level administration. All subjects come from a suburban Arizona school district. Upon achieving IRB approval, the researcher reached out to building level principals to ask if they would like to participate in the study. Once a principal agreed to participate, they sent out a Qualtrics questionnaire link to their teacher and parent stakeholder groups which asked potential subjects questions about parental involvement, and their contact information so they may be reached out to for participation in personal interviews. Each interview subject was asked a common set of questions based upon their stakeholder grouping. Personal interviews were recorded, transcribed, reviewed for accuracy, and thematically coded. The findings of this study suggest that the role of communication is more important than ever coming from school to parent. The school to parent communication can play the role of limiting anxiety among the parents. Further, the study finds that among this communication, teachers and parents both have increased time demands for parental involvement. Where the parent had more of a managerial role ensuring their students could log in to class, most teachers reported a heightened time demand for communications with families. This time demand was largely also felt by school principals during remote stages of COVID-19 schooling. The findings of this study also suggested that COVID-19 schooling creates a “window into the classroom,” where parental involvement takes on a different context than ever before in educational history
Examining adaptive learning impact on students' academic performance and perception of self-regulated learning skills
No full textAdaptive Learning, as a new online learning environment, intends to individualize the learning experience for each individual learner. Adaptive Learning suffers many shortcomings, as the date of the publication of this dissertation, however, it is considered the next generation of the learning environment for at least the next twenty years; because of its unique features such as the application of Artificial Intelligence, knowledge state, individualized learning, real-time computerized assessment, and immediate feedback. This new complex learning environment requires self-regulated learners who act autonomously and independently; However, there appears to be no existing model to conceptualize different aspects of SRL skills in Adaptive Learning Environments (ALE’s). The purpose of this study was to empirically evaluate a theoretical model of self-regulated learning (SRL) in ALE’s. In doing so, an eight-factor Adaptive Self-Regulated Learning (ASR) Model was designed based on which a 5-point Likert scale questionnaire (ASRQ) and an open-ended survey were developed and validated to qualitatively and quantitatively incorporate the SRL skills into ALE’s. The ASRQ, then, was used to empirically evaluate the predictive function of eight SRL skills of adaptive learning students working with an adaptive learning system (ALEKS). This questionnaire, moreover, investigated the improvement of SRL skills of students during a semester. Furthermore, the open-ended survey was employed to measure students’ perceptions of learning through an adaptive learning system. One hundred twenty undergraduate students in Chemistry 151 course, equipped with ALEKS, participated and filled out the questionnaire and survey in the beginning and at the end of a semester. The result of a quantitative analysis of the questionnaire indicated three out of eight SRL variables, including Goal-setting, Time-management, and Persistence, were the predictive utilities of the final grade. Also, the result of comparing the pre with post SRL scores showed a significant drop in SRL skills of the students conveying the malfunctioning of the system to improve these skills in the corresponding students. On the other hand, the analysis of the qualitative survey indicated a varied spectrum of students’ ideas about their perception, experience, and SRL skills while working with ALEKS. Additionally, the Educational Data Mining (EDM) was utilized to create comprehensive and a big data set from ALEKS system models, students’ self-report quantitative questionnaire, and the qualitative survey. These three sources of data were combined, classified, clustered, analyzed, and compared to indicate any abnormalities or similarities in the data gathered from these three sources. The results of EDM showed a similar pattern in this big comprehensive data set indicating the failing of the system to develop the SRL skills in students and highlighting the importance of Time-management, Goal-setting, Self-evaluation, and Persistence SRL skills in the ALEKS adaptive learning system
Genocidal Conscription: Drafting Victims of Genocide
Get PDF"Genocidal Conscription" examines the ways by which genocidal states have employed mandatory military service as a tool of genocide. This work applies a comparative study to trace the mechanisms by which states have drafted victims of genocide in two cases. The work contributes a theory and an interpretation of a typology of genocide. Evidence provided in this work supports the argument that certain genocidal states have subverted the institution of conscription into a tool of genocide. The implications consider the types of reform that may now be possible in a time of transition and transformation
Assessing longitudinal patterns of reproduction and stress of humpback whales (Megaptera novaeangliae) via a novel analytical technique using baleen
No full textUnderstanding the physiology of baleen whales is critical for their effective management and conservation but sampling free-living whales is exceedingly difficult. To overcome this issue, baleen was used to analyze hormone and mercury patterns, allowing for multi-year retrospective investigation into stress and reproductive physiology in humpback whales. Progesterone, an important reproductive hormone, showed an increase during periods of known pregnancy as confirmed by sighting data and strengthens the hypothesis that baleen can be used to determine pregnancy rates in humpback whales. Two glucocorticoids involved in metabolism and stress, cortisol and corticosterone, did not increase during pregnancy as seen in other mysticete species and highlights the need for additional studies into pregnancy physiology in baleen whales. Estradiol and testosterone, hormones involved in reproduction, did not show patterns of increase or decrease in females during period of known gestation or parturition. Analysis of cortisol and corticosterone patterns between whales with different fatality causes (ship strike, illness, or entanglement) showed discrepancies in glucocorticoid patterns depending on how the whale died. The whales that were fatally struck by ships had relatively low and stable glucocorticoid concentrations while a frequently entangled whale had exceptionally high corticosterone concentrations throughout the baleen. A chronically ill whale had concurrent increases in both hormones over the baleen plate until approximately six months before death when both hormones fell to very low levels. These results show that baleen analysis can be a useful tool to determine causes of death in both historical and present-day baleen plates. Mercury concentrations along the baleen plates revealed that individual prey preferences might influence baleen mercury levels more than sex or pregnancy. The female had 2-3 times higher mercury concentrations than the two males and levels peaked during the first half of lactation. The two males had similar values even though they were 31 years apart in age. Analysis of baleen allowed for a multi-year retrospective approach to determine glucocorticoid, progesterone, and mercury patterns during pregnancy and with varying causes of death in a hard to sample species. Further use of this method could result in increased understanding of baleen whale physiology during various life history events
Understanding social change through plant-based eating
No full textThe current reality in the United States with the production and consumption of animals is creating devastating health, animal welfare, and environmental outcomes. Living in a country with an omnivore majority, there is a compelling narrative forming in shifting away from animal consumption to more plant-based eating. That said, relying on government agencies to provide correct information or for the medical field to shift is wishful thinking and requires vast and expensive systematic change. Off of this, simply providing more information to individuals is not the clear-cut solution. Food emerges as a complex element within U.S. culture and addressing the micro, macro, and in-between synergies and factors is vital in having a foundational understanding of what is influencing or could influence a potential shift. It is critical to dive deeper into examining the psychology of U.S. individuals in their eating patterns, norms, and identity centered around food and how these forces interact with the cultural, product innovation, and positioning of food organizations and companies in the emerging plant-based sphere. In this analysis, we will strive to understand the current trends and build off prior research to shed light on what shifts consumers to shift from animal product consumption to plant-based products and how this can potentially transform plant-based eating from a minority to a majority behavior. To understand the multi-layered nature of this topic, we first ask what did U.S. consumers that follow a plant-based diet and do not consume animal products perceive as their mindset before shifting their diet and what other psychological mechanisms and information were vital to activate their behavior to emerge in a minority position within the total population? From this base perspective, what do these consumers perceive as critical catalysts and elements to aid those that consume animal products to shift to more plant-based consumption?
To balance this focus on consumer behavior, we explore what are the perceptions of those that are involved with marketing, product innovation, and positioning of food companies and organizations regarding the main drivers and catalysts toward plant-based eating in the face of this behavior and associated consumer offering being a minority in the U.S. market?
To answer these questions, we utilize the theory of minority influence and how it interplays with the motivations most effective in evoking dietary change, the latest findings in plant-based marketing and messaging, and lastly address the barriers that are paramount in promoting a transition to a plant-based diet. Ultimately, this analysis will serve to inform educational material and programming to yield improved health outcomes and lower environmental impact
Missing and murdered Indigenous people’s representation in northern Arizona: inquiring about settler colonialism in print
No full textAs an Indigenous person, my exploration into the newsprint media articles is an exploration into understanding stories. It is through these stories that I understand the world. As an Indigenous anthropologist, I aim to disrupt the settler-colonial narratives of the past and present by using frameworks of Indigenous scholarship to investigate perceptions of the media regarding MMIP (Missing and Murdered Indigenous Peoples). In this thesis I inquire about the representation of Missing and Murdered Indigenous People (MMIP) through various forms of media in Northern Arizona. I draw on insights about The Navajo-Hopi Observer (NHO), and The Arizona Daily Sun (ADS). I also look at new media, internet and digital technologies that use digital audio files including the Indigenous podcast The Red Nation. I suggest that there are ways in which language normalizes violence when discussing Indigenous People and communities and there is a lack of coverage on Missing and Murdered Indigenous men and LGBTQ+ persons. New media offers a reframing of the issue to connect history with present issues and do so meaningfully. To conclude this study, I urge people in publishing to portray Indigenous peoples accurately and move away from stereotypes and provide historical context to bring awareness to MMIP. This encouraged approach includes responsible use of statistical data by experts to discuss why the MMIP issue is so prevalent. New Media such as The Red Nation podcast has already done this and provides a model for discussing the issues that surround MMIP