81 research outputs found

    Interactive 3-D Visualization: A tool for seafloor navigation, exploration, and engineering

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    Recent years have seen remarkable advances in sonar technology, positioning capabilities, and computer processing power that have revolutionized the way we image the seafloor. The massive amounts of data produced by these systems present many challenges but also offer tremendous opportunities in terms of visualization and analysis. We have developed a suite of interactive 3-D visualization and exploration tools specifically designed to facilitate the interpretation and analysis of very large (10\u27s to 100\u27s of megabytes), complex, multi-component spatial data sets. If properly georeferenced and treated, these complex data sets can be presented in a natural and intuitive manner that allows the integration of multiple components each at their inherent level of resolution and without compromising the quantitative nature of the data. Artificial sun-illumination, shading, and 3-D rendering can be used with digital bathymetric data (DTM\u27s) to form natural looking and easily interpretable, yet quantitative, landscapes. Color can be used to represent depth or other parameters (like backscatter or sediment properties) which can be draped over the DTM, or high resolution imagery can be texture mapped on bathymetric data. When combined with interactive analytical tools, this environment has facilitated the use of multibeam sonar and other data sets in a range of geologic, environmental, fisheries, and engineering applications

    Federalism Revisited: The Supreme Court Resurrects the Notion of Enumerated Powers by Limiting Congress\u27s Attempt to Federalize Crime Comment.

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    This Comment argues the federal system must be preserved and the Supreme Court should build upon the interpretation of the Commerce Clause in United States v. Lopez to reinstate the Framersā€™ vision of federalism. The social justifications for the Courtā€™s expansive construction of the Commerce Clause during the past sixty years no longer existed to justify the Gun-Free School Zones Act of 1990. Part II of this Comment traces the background of Commerce Clause jurisprudence, focusing on social justifications for traditional rubber stamping of Congressā€™s broad exercises of power. Part III reviews the Fifth Circuitā€™s reasoning in deeming the Gun-Free School Zones Act unconstitutional. Part IV summarizes the Courtā€™s majority, concurring, and dissenting opinions in Lopez. Part V analyzes federal gun control efforts and argues the Court was justified in holding Congress exceeded its powers when it passed the Gun-Free School Zones Act. Finally, Part VI concludes the Court should analyze congressional findings of fact more discriminately in deciding what constitutes interstate commerce. Additionally, the Court should generally allow the states to freely exercise their traditional regulatory powers without threat of federal preemption. The Court sent a clear message with its decision in Lopez: Congress should restrain its recent penchant for federalizing crime to pacify alarmed voters. The most realistic framework for Commerce Clause jurisprudence is one based in fact. Congressional findings must be present and show some substantial impact on interstate commerce exists before allowing Congress to regulate a local activity. Such a test would allow the Framersā€™ vision of federalism to operate as originally intended. Most importantly, however, individual state legislatures could once again serve as the proving grounds for the substantive social policies that will guide our nation into the twenty-first century. The Courtā€™s decision in Lopez is only the first step

    Advanced Mid-Water Tools for 4D Marine Data Fusion and Visualization

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    Mapping and charting of the seafloor underwent a revolution approximately 20 years ago with the introduction of multibeam sonars -- sonars that provided complete, high-resolution coverage of the seafloor rather than sparse measurements. The initial focus of these sonar systems was the charting of depths in support of safety of navigation and offshore exploration; more recently innovations in processing software have led to approaches to characterize seafloor type and for mapping seafloor habitat in support of fisheries research. In recent years, a new generation of multibeam sonars has been developed that, for the first time, have the ability to map the water column along with the seafloor. This ability will potentially allow multibeam sonars to address a number of critical ocean problems including the direct mapping of fish and marine mammals, the location of mid-water targets and, if water column properties are appropriate, a wide range of physical oceanographic processes. This potential relies on suitable software to make use of all of the new available data. Currently, the users of these sonars have a limited view of the mid-water data in real-time and limited capacity to store it, replay it, or run further analysis. The data also needs to be integrated with other sensor assets such as bathymetry, backscatter, sub-bottom, seafloor characterizations and other assets so that a ā€œcompleteā€ picture of the marine environment under analysis can be realized. Software tools developed for this type of data integration should support a wide range of sonars with a unified format for the wide variety of mid-water sonar types. This paper describes the evolution and result of an effort to create a software tool that meets these needs, and details case studies using the new tools in the areas of fisheries research, static target search, wreck surveys and physical oceanographic processes

    A Conversational Goal Setting Buddy for Student Learning

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    Time management and goal setting skills are essential for student academic success in higher education. Meanwhile, the recent advances of chatbots offer new opportunities to support goal setting in a conversational way. In this preliminary research, we investigate the effects of chatbots as a conversational goal setting tool for student learning. We developed a chatbot called Sammy that invites students to pledge their study goals and reflect on their goal completion. We conducted a 7-day study among 70 undergraduate students. Analysis on pre- and post-study surveys indicated a significant improvement in student perceived time management in learning goals. Analysis on student daily check-in with Sammy showed an upward trend of student satisfaction in goal completion and confidence in future goal setting. In the future, we will conduct a more comprehensive mixed-method analysis, improve the functionalities and usability of Sammy, and conduct longitudinal studies

    Collective Teacher Efficacy in Queensland Secondary School Staffrooms

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    This thesis examines the nature and strength of the relationship between collective teacher efficacy (CTE) at the staffroom level and student academic achievement in four secondary schools in Queensland, Australia. CTE refers to the aggregate beliefs of a group of teachers in their joint capabilities to positively influence students under their care. It is founded on Bandura's social cognitive theory (1986, 1997) and models of collective efficacy developed primarily by R. Goddard between 1998 and 2004. The study is unique in that it includes analysis of CTE at the staffroom level rather than only the whole school or individual teacher levels. CTE was measured in the study by a survey instrument developed by the author - the Australian Collective Efficacy Survey (ACES). The survey is based on Goddardā€™s 2002 Collective Efficacy Survey (CES) developed in the United States. The principal analytical tool used in the study was one-way between-groups analysis of variance (ANOVA). This tested the strength of association between CTE, current student academic achievement and six other variables thought to be associated with CTE. Results indicated that CTE had a moderate effect on current student achievement. Differences in prior student achievement held the greatest power in explaining variance in current student achievement. There was also a strong association between student socioeconomic status (SES) and current student achievement. Variance in CTE was explained mostly by variations in teacher experience and staffroom longevity. Student SES also had a large effect on CTE. Results support the idea that a higher proportion of experienced teachers in secondary schools is more conducive for a stronger sense of CTE. However, the study did not demonstrate that this translated into improved student academic outcomes. ii Principal Components Analysis (PCA) of the ACES indicated that the instrument displayed acceptable consistency and reliability for measuring CTE. Consistent with previous measures of CTE, two underlying survey components of CTE were identified: task analysis and group competence. Results did not support the key assumption of social cognitive theory that perceived collective teaching expertise (mastery experience) influences CTE. The strong, positive association between prior academic success and CTE at the school level, indicated in previous studies, was not present at the staffroom level in this study. Further studies of CTE at a variety of levels are needed to determine whether teacher experience and staffroom longevity are embodiments of perceived teaching expertise (mastery experience)

    Tracking the Late Jurassic apparent (or true) polar shift in U-Pb-dated kimberlites from cratonic North America (Superior Province of Canada)

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    Different versions of a composite apparent polar wander (APW) path of variably selected global poles assembled and averaged in North American coordinates using plate reconstructions show either a smooth progression or a large (āˆ¼30Ā°) gap in mean paleopoles in the Late Jurassic, between about 160 and 145 Ma. In an effort to further examine this issue, we sampled accessible outcrops/subcrops of kimberlites associated with high-precision U-Pb perovskite ages in the Timiskaming area of Ontario, Canada. The 154.9ā€‰Ā±ā€‰1.1 Ma Peddie kimberlite yields a stable normal polarity magnetization that is coaxial within less than 5Ā° of the reverse polarity magnetization of the 157.5ā€‰Ā±ā€‰1.2 Ma Triple B kimberlite. The combined āˆ¼156 Ma Triple B and Peddie pole (75.5Ā°N, 189.5Ā°E, A95ā€‰=ā€‰2.8Ā°) lies about midway between igneous poles from North America nearest in age (169 Ma Moat volcanics and the 146 Ma Ithaca kimberlites), showing that the polar motion was at a relatively steady yet rapid (āˆ¼1.5Ā°/Myr) pace. A similar large rapid polar swing has been recognized in the Middle to Late Jurassic APW path for Adria-Africa and Iran-Eurasia, suggesting a major mass redistribution. One possibility is that slab breakoff and subduction reversal along the western margin of the Americas triggered an episode of true polar wander

    U.S. Billion-ton Update: Biomass Supply for a Bioenergy and Bioproducts Industry

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    The Report, Biomass as Feedstock for a Bioenergy and Bioproducts Industry: The Technical Feasibility of a Billion-Ton Annual Supply (generally referred to as the Billion-Ton Study or 2005 BTS), was an estimate of ā€œpotentialā€ biomass within the contiguous United States based on numerous assumptions about current and future inventory and production capacity, availability, and technology. In the 2005 BTS, a strategic analysis was undertaken to determine if U.S. agriculture and forest resources have the capability to potentially produce at least one billion dry tons of biomass annually, in a sustainable mannerā€”enough to displace approximately 30% of the countryā€™s present petroleum consumption. To ensure reasonable confidence in the study results, an effort was made to use relatively conservative assumptions. However, for both agriculture and forestry, the resource potential was not restricted by price. That is, all identified biomass was potentially available, even though some potential feedstock would more than likely be too expensive to actually be economically available. In addition to updating the 2005 study, this report attempts to address a number of its shortcoming

    Altered age-related trajectories of amygdala-prefrontal circuitry in adolescents at clinical high risk for psychosis: A preliminary study

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    Emotion processing deficits are prominent in schizophrenia and exist prior to the onset of overt psychosis. However, developmental trajectories of neural circuitry subserving emotion regulation and the role that they may play in illness onset have not yet been examined in patients at risk for psychosis. The present study employed a cross-sectional analysis to examine age-related functional activation in amygdala and prefrontal cortex, as well as functional connectivity between these regions, in adolescents at clinical high risk (CHR) for psychosis relative to typically developing adolescents. Participants (n=34) performed an emotion processing fMRI task, including emotion labeling, emotion matching, and non-emotional control conditions. Regression analyses were used to predict activation in the amygdala and ventrolateral prefrontal cortex (vlPFC) based on age, group, sex, and the interaction of age by group. CHR adolescents exhibited altered age-related variation in amygdala and vlPFC activation, relative to controls. Controls displayed decreased amygdala and increased vlPFC activation with age, while patients exhibited the opposite pattern (increased amygdala and decreased vlPFC activation), suggesting a failure of prefrontal cortex to regulate amygdala reactivity. Moreover, a psychophysiological interaction analysis revealed decreased amygdala-prefrontal functional connectivity among CHR adolescents, consistent with disrupted brain connectivity as a vulnerability factor in schizophrenia. These results suggest that the at-risk syndrome is marked by abnormal development and functional connectivity of neural systems subserving emotion regulation. Longitudinal data are needed to confirm aberrant developmental trajectories intra-individually and to examine whether these abnormalities are predictive of conversion to psychosis, and of later deficits in socioemotional functioning

    Reliability of functional magnetic resonance imaging activation during working memory in a multi-site study: Analysis from the North American Prodrome Longitudinal Study

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    Multi-site neuroimaging studies offer an efficient means to study brain functioning in large samples of individuals with rare conditions; however, they present new challenges given that aggregating data across sites introduces additional variability into measures of interest. Assessing the reliability of brain activation across study sites and comparing statistical methods for pooling functional data is critical to ensuring the validity of aggregating data across sites. The current study used two samples of healthy individuals to assess the feasibility and reliability of aggregating multi-site functional magnetic resonance imaging (fMRI) data from a Sternberg-style verbal working memory task. Participants were recruited as part of the North American Prodrome Longitudinal Study (NAPLS), which comprises eight fMRI scanning sites across the United States and Canada. In the first study sample (n = 8), one participant from each home site traveled to each of the sites and was scanned while completing the task on two consecutive days. Reliability was examined using generalizability theory. Results indicated that blood oxygen level-dependent (BOLD) signal was reproducible across sites and was highly reliable, or generalizable, across scanning sites and testing days for core working memory ROIs (generalizability ICCs = 0.81 for left dorsolateral prefrontal cortex, 0.95 for left superior parietal cortex). In the second study sample (n = 154), two statistical methods for aggregating fMRI data across sites for all healthy individuals recruited as control participants in the NAPLS study were compared. Control participants were scanned on one occasion at the site from which they were recruited. Results from the image-based meta-analysis (IBMA) method and mixed effects model with site covariance method both showed robust activation in expected regions (i.e. dorsolateral prefrontal cortex, anterior cingulate cortex, supplementary motor cortex, superior parietal cortex, inferior temporal cortex, cerebellum, thalamus, basal ganglia). Quantification of the similarity of group maps from these methods confirmed a very high (96%) degree of spatial overlap in results. Thus, brain activation during working memory function was reliable across the NAPLS sites and both the IBMA and mixed effects model with site covariance methods appear to be valid approaches for aggregating data across sites. These findings indicate that multi-site functional neuroimaging can offer a reliable means to increase power and generalizability of results when investigating brain function in rare populations and support the multi-site investigation of working memory function in the NAPLS study, in particular

    Reliability of an fMRI paradigm for emotional processing in a multisite longitudinal study

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    Multisite neuroimaging studies can facilitate the investigation of brain-related changes in many contexts, including patient groups that are relatively rare in the general population. Though multisite studies have characterized the reliability of brain activation during working memory and motor functional magnetic resonance imaging tasks, emotion processing tasks, pertinent to many clinical populations, remain less explored. A traveling participants study was conducted with eight healthy volunteers scanned twice on consecutive days at each of the eight North American Longitudinal Prodrome Study sites. Tests derived from generalizability theory showed excellent reliability in the amygdala ( EĻ2 = 0.82), inferior frontal gyrus (IFG; EĻ2 = 0.83), anterior cingulate cortex (ACC; EĻ2 = 0.76), insula ( EĻ2 = 0.85), and fusiform gyrus ( EĻ2 = 0.91) for maximum activation and fair to excellent reliability in the amygdala ( EĻ2 = 0.44), IFG ( EĻ2 = 0.48), ACC ( EĻ2 = 0.55), insula ( EĻ2 = 0.42), and fusiform gyrus ( EĻ2 = 0.83) for mean activation across sites and test days. For the amygdala, habituation ( EĻ2 = 0.71) was more stable than mean activation. In a second investigation, data from 111 healthy individuals across sites were aggregated in a voxelwise, quantitative meta-analysis. When compared with a mixed effects model controlling for site, both approaches identified robust activation in regions consistent with expected results based on prior single-site research. Overall, regions central to emotion processing showed strong reliability in the traveling participants study and robust activation in the aggregation study. These results support the reliability of blood oxygen level-dependent signal in emotion processing areas across different sites and scanners and may inform future efforts to increase efficiency and enhance knowledge of rare conditions in the population through multisite neuroimaging paradigms
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