1925 research outputs found
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Crustal structure of the Alaska subduction zone across the 2021 m8.2 Chignik earthquake rupture area from wide-angle seismic data
Full text linkUnderstanding the influence of large-scale crustal structure on megathrust slip behavior is essential for evaluating seismic and tsunami hazards at convergent plate margins. The subduction zone offshore of the Alaskan Peninsula is an excellent area to examine controls on subduction zone behavior because it has experienced a sequence of recent large earthquakes and it exhibits dramatic along-strike variability in seismicity and geodetic locking. The incoming sediments and oceanic plate in this region have been cited as factors controlling variability in megathrust slip behavior, but the influence of the overriding continental plate is less well studied. Here we focus on the Semidi segment of the Alaska subduction zone, which is strongly locked and regularly ruptures in great (M>8) megathrust earthquakes, including the July 2021 M8.2 Chignik earthquake. We present a two-dimensional P-wave seismic velocity model along a ~365-km-long profile obtained by joint reflection-refraction tomographic inversion of wide-angle seismic (WAS) data collected in 2011 aboard the R/V Marcus G. Langseth. Model uncertainty was estimated using a Monte Carlo approach. The resulting P-wave velocity model displays large-scale velocity variations in the overriding plate that constrain the extent of the accretionary prism and accreted crustal terranes that form the overriding plate: the Prince William and Chugach terranes. Shallow slow slip and afterslip are focused beneath the accretionary prism and younger, lower velocity Prince William Terrane while rupture in the 2021 earthquake is concentrated below the higher velocity Chugach terrane, suggesting that the upper plate influences slip behavior here
Exploring impacts of on-site sports betting for parents and families at live sporting events
No full textHow has the implementation of sports betting at arenas across the country impacted the fanexperience (i.e. enjoyment of the game, arena, and time spent with others in attendance) for
families attending the game with children? To answer this question a survey was conducted
amongst 16 parents of young children (under 14) who had attended Phoenix Suns games both
before and after the implementation of sports betting on-site. We find that the implementation of
sports betting has had a limited impact on the fan experience for families, notably limited in
regard to misconduct by sports bettors in attendance. Parents did raise concerns in regards to The
Footprint Center’s partnership with FanDuel Sportsbook saying it had negatively impacted their
perception of The Phoenix Suns organization. Furthermore, 1 in 4 respondents said they were
hesitant to attend future games with their children due to the implementation of sports betting at
the arena
Regeneration and recruitment for resilience: sustaining aspen ecosystems threatened by climate change, ungulate browse, and oystershell scale
Full text linkQuaking aspen (Populus tremuloides) ecosystems are highly valued in the southwestern United States because of the ecological, economic, and aesthetic benefits they provide. Concerningly, aspen has experienced extensive mortality in recent decades, and there is evidence that many areas in Arizona, USA lack adequate recruitment to replace dying overstory trees. Maintaining sustainable levels of regeneration and recruitment is necessary for facilitating resilience to biotic and abiotic disturbance agents and for maximizing aspen’s ability to adapt in an increasingly uncertain future. However, questions remain about which factors currently limit aspen regeneration and recruitment in Arizona and which strategies are appropriate for promoting aspen sustainability. Moreover, recent outbreaks of an invasive insect, oystershell scale (Lepidosaphes ulmi; OSS) pose a new threat to aspen forest health. Because these are the first documented outbreaks of OSS in aspen ecosystems, there is an urgent need to survey the extent and impacts of these invasions and to better understand the insect’s biology and ecology on aspen in Arizona. To fill these knowledge gaps, we conducted a systematic literature review of aspen in the Southwest to understand how biotic and abiotic factors, including management, influence aspen forest dynamics (Chapter 1). We also sampled aspen populations across Arizona to quantify the sustainability and drivers of aspen regeneration and recruitment (Chapter 2) and impacts and drivers of OSS invasions (Chapter 3). Finally, we used repeated measurements of OSS-infested aspen stands to quantify short-term rates of OSS intensification on trees, OSS spread among trees, and aspen mortality, and we collected OSS from these stands to document the insect’s phenology in northern Arizona (Chapter 4).We found that many aspen populations in Arizona lack sustainable regeneration and recruitment. The status of recruitment was especially dire, with 40% of study plots lacking a single recruiting stem. Aspen regeneration was less abundant on warmer, drier sites, highlighting the threat that a warming climate poses to aspen sustainability. Aspen recruitment was significantly more abundant in areas with recent fire and more severe fire. The most important factors limiting recruitment were OSS and browsing by ungulates, especially Rocky Mountain elk (Cervus canadensis). OSS was widespread in Arizona and was associated with increased aspen crown damage and mortality. Climate was the most important driver of OSS abundance, with warmer, drier conditions resulting in significantly more OSS. OSS was also associated with less recent fire, presence of ungulate management strategies such as fenced exclosures, and stands with a greater density of aspen saplings. We also found that immature OSS life stages persist throughout the year and that there are two waves of first-instar crawlers in northern Arizona, one throughout the summer and the second in mid-winter. The first wave seemed to be driven by warming temperatures, but the cause of the second wave is unknown and might represent the initiation of a second generation. We also found that OSS causes high levels of mortality and spreads rapidly within aspen stands. We conclude by discussing how our findings can inform contemporary management of aspen and OSS (Chapter 5)
Culturally responsive teaching professional development for special educators in rural areas via digital learning technology.
No full textThis study examined how participants perceived the experience of receiving culturally responsive teaching (CRT) professional development (PD) for special education teachers via short message service (SMS) in a rural area. Six teachers received the CRT PD non-formal learning course. To establish experimental control, the researcher used a convergent parallel mixed-methods design to analyze survey data and interviews, perform social network analysis, and incorporate data triangularization. The findings showed that participants perceived the experience of receiving CRT PD via SMS as good or excellent. Results also showed more advantages than disadvantages of receiving CRT PD via SMS in a rural area. The learner’s device may have affected learner-instructor connectivity rates during the study. Learners affected interconnectivity rates either at a lower or higher level based on the amount of learner-learner and learner-instructor connectivity that occurred. However, the practice of delivering PD via a mobile device exclusively through SMS is a new practice in the field of mobile learning
The post-fire environment: understory plant recovery following high-severity fire and plant trait responses to increased soil temperature in a ponderosa pine ecosystem
Full text linkThe ponderosa pine forests of the Southwest have experienced dramatic changes since Euroamerican settlement which has led to stands with a closed overstory canopy with few fragmented grass openings intermixed. Long periods of drought combined with overly dense forests have increased the frequency of high-severity, stand replacing fires in forests that are historically adapted to high frequency, low-severity wildfires. Under climate change and the Southwest's changing precipitation pattern, it is anticipated that high-severity wildfires and dry fuel loads will continue to occur at increasing rates. In order to prepare these ecosystems for future change and predict changes in biodiversity, it is imperative to understand how the understory plant community of ponderosa pine ecosystems is altered following a severe wildfire, and how plants respond to an increasingly stressful post-fire environment. We monitored vegetation in understory communities impacted by high-severity fire in 2019 to ask: 1) How does high-severity fire change the proportion of plant functional groups and native/nonnative species in the understory of ponderosa pine ecosystems? 2) Following high-severity fire, do Festuca arizonica, Muhlenbergia virescens, and Ceanothus fendleri occur in different microhabitats? 3) How do the plant communities immediately surrounding F. arizonica, M. virescens, and C. fendleri in the high-severity burn area differ? and 4) How does soil temperature affect trait expressions of F. arizonica, M. virescens, and C. fendleri? Monitoring of plant cover and composition for three years following the Museum Fire determined that high-severity fire promoted an increase in nonnative forb cover, and a decrease in perennial graminoid cover compared to low-severity and unburned patches of forest. Species cover in neighborhoods immediately surrounding three species in the high-severity burn area revealed higher biodiversity near the dominant C4 grass, M. virescens, and a decrease in biodiversity near the C3 grass, F. arizonica. Evenness and Shannon index values were highest near F. arizonica. Increasing soil temperature decreases neighborhood richness for all species, indicating that increased environmental stresses can decrease understory biodiversity. C. fendleri and F. arizonica responded to increasing soil temperatures with opposite leaf dry matter content (LDMC) strategies. This suggests that under increasing temperature stress, some species increase LDMC to be resource conservative, and others can decrease LDMC suggesting they have not hit a temperature stress threshold that is limiting growth rate. Under projected climate change scenarios and following high-severity fire, we may see a decrease in understory biodiversity that needs active management for recovery
Three key post-secondary options for learning disability students at Casa Grande Union High School District
Full text linkThe transition from high school to the post-secondary world for students with disabilities can be challenging. The ability to successfully identify these exclusive needs can determine the socio-economic trajectory for students with a learning disability. Fortunately, there are several post-secondary options available for the students upon graduation. These options include, but are not limited to, enrolling in community colleges or universities, participation in trade or
vocational training programs, or entering competitive integrated employment. The purpose of this study is to examine whether relationships exist between survey results and demographics (gender, ethnicity, and disability) within the three key post-secondary options in the Casa Grande Union High School District in Casa Grande, Arizona. The knowledge gained from this study hopefully will help determine how Casa Grande Union High School District can decrease the gap when assisting students with post-secondary options. This could also improve the students chances of being self-sufficient and ultimately, live successful lives
Data-intensive ecological modeling and informatics tools
Full text linkThe advent of enormous observations and measurements offers tremendous potential to improve our predictive understanding of ecological processes under global climate change. However, despite the abundance of data, the ability of ecological prediction is limited. It remains challenging to translate the ultimate value of big data into actionable insights. The overall research question in my dissertation is how to develop informatics frameworks that can better integrate big data with process-based models to improve predictive understanding of ecological processes and ecological forecast of future ecosystem states. In Chapter 1, I introduce the motivation, data diversity, and current research state on ecological prediction. In Chapter 2, I present a model-independent data assimilation (MIDA) module. The easy-to-use capability of MIDA enables ecologists to conduct data model fusion in various applications. In Chapter 3, I apply MIDA in an 8-yr tundra warming experiment to advance our mechanistic understanding of how carbon cycle in the tundra ecosystem would change with global warming. I found that without considering elevated water table depth, the Terrestrial ECOsystem (TECO) model will underestimate carbon emissions. In Chapter 4, I develop an assessment method to evaluate the effects of forcing corrections on the improvement of forecast accuracy. Compared to the conventional method, this new assessment method can identify the decrease in forecast accuracy for pool-based variables (e.g., Leaf). I also found that only response variables with memory (e.g., carbon pools) can benefit from periodic forcing correction. In Chapter 5, I conclude all findings in my dissertation and provide my perspectives on data-model integration to advance our predictive understanding of the land carbon cycle. Overall, my dissertation work develops new informatic tools and methods to tackle three uncertainty sources (i.e., empirical parameter values, incomplete model structures, and unrealistic future forcings) which impede realistic ecological predictions. My dissertation indicates an avenue about how to translate big data to improvements in the predictive capability of terrestrial ecosystem carbon cycles. Furthermore, it will benefit policy making about mitigating global warming and the associated climate change
Cache performance and dynamic memory protection in embedded systems
Full text linkIn embedded system design, there is an ever-increasing need to improve security to meet the demands imposed by cyber-attack advancement. Key to the security of embedded systems are ways to exchange information between trusted zones and external memories vulnerable to attacks. System designers face the issue of increased program execution times due to increasingly complex security hardware. The research in this thesis is part of a larger effort to design a secure processor that develops specialized cryptographic and data randomization techniques in hardware. This thesis integrates caching to increase the security and performance of the secure processor. The design approach of the instruction and data caches allows us to test the effectiveness of cache size versus performance. The caches also interface with a shielding module that implements a dynamic computational diversity architecture. The shielding module and the caches implement continuous and periodic memory shuffling to protect against learning-based attacks. This thesis performs tests for execution time, perceived randomness of data, and hardware utilization. These results assess and optimize system security, computation, and hardware resource use
The effect of web-based pragma-prosodic instruction and aptitude on learner pragmatic development
Full text linkDespite the importance that learners must place on using prosody appropriately in EIL interaction, pragmatic functions of prosody have been largely disregarded in teaching materials and classroom instruction (Nikolić, 2018). Moreover, with a recent change in classroom paradigms instigated by the global development of educational technologies and reinforced by the recent pandemic, there is an increased need for pragmatic instruction that can be delivered to learners digitally and remotely (Taguchi, 2011b). Although distance learning has played an important role in English teaching and learning long before the pandemic, its impact is even more meaningful today, when English learners all over the world are still experiencing difficulties related to in-person instructional access. The current mixed-methods quasi-experimental dissertation study investigated the extent to which English learners’ interaction skills can improve as a result of contextualized prosody instruction on a web-based platform. Seventy-four English learners from China were randomly assigned to a two-week program that consisted of explicit pragma-prosodic instruction as well as perception- and production-based exercises. Learners’ use of prosody in requests before and after instruction was recorded through video-based role plays, analyzed acoustically, and evaluated for appropriateness, accentedness, and comprehensibility by 20 trained raters. In order to provide a complete picture of instructional effectiveness, the study accounted for variation in learners’ aptitude for acquiring prosodic properties of English by measuring their working memory, musical sensitivity, and auditory processing skills.
The study results demonstrated significant changes in learners’ use of pragma-prosodic features of interaction after the training; however, these changes did not have an effect on listeners’ appropriateness perceptions, highlighting the complex nature of this construct that requires further clarification. At the same time, a significant albeit weak relationship was detected among listeners’ perceptions of accentedness, comprehensibility, and appropriateness. Finally, the results revealed that learners’ musical sensitivity, working memory as well as tone choice and prominence discrimination ability affected the success of the training in improving their use of pragma-prosodic features from the acoustic perspective. These findings provide important guidance for designing digitally mediated contextualized prosody instruction and help to better understand the role of learners’ aptitude in its effectiveness
Portraiture: How Caucasian teachers build trusting relationships and bridge the cultural divide
Full text linkEducators are continuously challenged with ensuring that their students are capable of reaching their full potential. While trying to push students to do their best educators must also work to ensure that they are creating an accepting and welcoming environment for the diverse learners of today. Despite the diversity of the classroom a majority of the teaching staff throughout the nation are Caucasian, middle class, and generally female. The purpose of this study is to portray the universal themes that are present when creating and maintaining trusting relationships with students from diverse backgrounds. The significance of this study is to provide schools and teachers with the tools necessary to create relationships with students of different backgrounds than themselves. Doing this will improve the experiences for both teachers and students within schools. The research design for this is a qualitative study using the portraiture methodology. Through the use of interviews and observations the research questions will be answered through the portraits of the individual participants. The participants of each portrait will consist of Caucasian high school teachers from two different campuses. The teachers’ portraits are educators who work in public schools in the Southwestern United States. These portraits will illustrate the complexities in building trusting relationships between students and teachers of differing backgrounds and ethnicities. These findings will reveal the factors and themes necessary in creating student-teacher relationships to ensure that the school experience for diverse students is a positive one