471 research outputs found

    The Terwilliger algebra of an almost-bipartite P- and Q-polynomial association scheme

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    Let YY denote a DD-class symmetric association scheme with D3D \geq 3, and suppose YY is almost-bipartite P- and Q-polynomial. Let xx denote a vertex of YY and let T=T(x)T=T(x) denote the corresponding Terwilliger algebra. We prove that any irreducible TT-module WW is both thin and dual thin in the sense of Terwilliger. We produce two bases for WW and describe the action of TT on these bases. We prove that the isomorphism class of WW as a TT-module is determined by two parameters, the dual endpoint and diameter of WW. We find a recurrence which gives the multiplicities with which the irreducible TT-modules occur in the standard module. We compute this multiplicity for those irreducible TT-modules which have diameter at least D3D-3.Comment: 22 page

    Five Tectonic Settings in Five National Parks and Forests: A Field Camp Experience

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    In summer 2014, Southern Utah University’s field camp visited five national parks and forests to study five different tectonic settings in five weeks. These included: thick-skinned contraction of the Laramide Orogeny at Capitol Reef National Park; normal faulting due to salt tectonics of the Paradox Formation at Arches National Park; thin-skinned folding and thrusting of the Sevier Orogeny at Fish Lake National Forest and Kolob Canyon of Zion National Park; foreland sedimentary transitions in the Book’s Cliffs areas of Utah; thrusting and conjugate fracture development due to the gravitational collapse of the Marysvale volcanic field at Bryce Canyon National Park; and a metamorphic core complex at Great Basin National Park and Hendry’s Creek in the Northern Snake Range of Nevada. This article provides a brief summary and photographic tour of the students’ experiences studying each tectonic environment, and it highlights wonderful geological features exposed in our national parks

    Orientation of Paleostress of Raplee Ridge Anticline

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    During the Laramide Orogeny several major folds were formed in Southern Utah, one of those being the Raplee Ridge anticline. Raplee Ridge is approximately eight miles from Mexican Hat, Utah. The San Juan River cuts through the anticline, exposing the Honaker Trail Formation’s beds of shale and limestone with chert nodules. Accompanying the mountain-scale ductile deformation of the Raplee Ridge anticline are decimeter-scale brittle conjugate fractures in the limestone’s chert nodules. The objective of this study is to compare the orientation of paleostress that formed the Raplee Ridge anticline with the conjugate fractures within the chert nodules to see if the two different styles of deformation could have occurred during the same orogeny

    Semester in the Parks: Engaging Students with Common Intellectual Experiences

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    High-impact educational practices (HIP) such as Common Intellectual Experiences (CIE) enhance student engagement and positively affect student learning. At Southern Utah University we created a new HIP-focused program to enrich our students and faculty: Semester in the Parks (SIP). Students lived outside of Bryce Canyon National Park in the gateway community of Bryce Canyon City while they worked for Ruby’s Inn Resort and learned about the national parks. Faculty commuted to this off campus venue and redesigned their courses to incorporate national parks thinking and experiential learning opportunities. The CIE of a national parks-focused semester enhanced student engagement and developed the pedagogical ability of faculty. Program assessment revealed positive gains in student and faculty self-report measures but also identified the need for other assessment tools and comparison groups. We conclude that CIE, even those set in nontraditional classroom locations, have great potential to enhance student growth and faculty professional development

    Evidence of Large Scale Tectonic Processes on the Tharsis Rise, Mars

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    Past observations of Mars have led scientists to believe that tectonic kinematics stopped early in its planetary development. Recent exploration of Mars has led to new theories that support an active tectonic regime on the Tharsis rise. With the advancement of new satellite imagery and technologies such as Thermal Emission Imaging System, High Resolution Imaging Science Experiment satellite imagery, the Mars Orbital Laser Altimeter, and interactive software such as J-Mars and Esri GIS, we have identified additional large-scale surface features in the Tharsis Rise and surrounding areas. Large-scale Martian lineations, folds, and conjugate joints can be compared to similar structures on Earth to interpret potential plate boundaries. For example, a northeast-trending set of lineations with significant left-lateral strike-slip displacement and conjugate jointing located to the northeast of the Tharsis Rise could accommodate transform motion between two plates. Our observations allow the designation of multiple potential plate margins in the region. We propose a tectonic model showing relative motions along plate boundaries in a potentially active multiple-plate system on Mars

    Extent and Mechanism of Footwall Shear Adjacent to the Ruby\u27s Inn Thrust Fault, Southern Utah

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    The Ruby’s Inn Thrust, located in the Bryce Canyon region, is an uncharacteristic demonstration of a south-directed shortening episode located near the predominately east-directed contractional structures of the Sevier Orogeny. The Paleocene to Eocene Claron Formation in the footwall of the Ruby’s Inn Thrust contains conjugate shear structures and vertical fault planes with slickensides and slickenlines, indicating complex multidirectional shearing. We determined the north-south extent of a broad shear zone along a traverse immediately west of Bryce Canyon National Park, and shearing intensifies slowly from the main thrust at the northern end of our traverse to a maximum intensity at 13 kilometers south of the thrust, where it then gradually diminishes until an abrupt end approximately 29 kilometers south of the thrust. No evidence of conjugate shear structures in the hanging wall of the thrust was observed. The footwall outcrops adjacent to the thrust and at the southern portion of the traverse contained the structures, but they were more difficult to visually recognize, whereas the structures within the outcrops of the central region were obvious. The conjugate shear structures crosscut bedding and vary from small scale (a few centimeters) to large scale (tens of meters) throughout each outcrop, and are best observed parallel to their east-west strike. The conjugate shear structures contain distinct structural planar surfaces that include very well developed slickensides and slickenlines. This research supports the idea that the deformation structures were a significant contributor in the formation of hoodoos found in the Claron Formation

    Strain Accomodation in the Footwall of the Rubys Inn Thrust Fault, Hillsdale Canyon, Southern Utah

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    The Rubys Inn thrust fault in southern Utah has produced several styles of deformation in its footwall. This project describes four exceptionally well exposed examples of strain accommodation, including a mountain-scale, ductile footwall drag fold, cataclastic flexural slip between bedding surfaces of differing competencies, plastically deformed petrified wood within the zone of flexural slip, and cataclastic shear expressed as deformation bands. Such examples show how various lithologies can be deformed into a wide array of structures during a single deformation event. Furthermore, some of these structures result in changes in permeability, which are important for those interested in subsurface fluid flow

    Increased aerobic capacity reduces susceptibility to acute high‐fat diet‐induced weight gain

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134165/1/oby21564.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134165/2/oby21564_am.pd

    Molecular and morphological analysis of subfamily Alooideae (Asphodelaceae) and the inclusion of chortolirion in aloe

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    Asphodelaceae subfam. Alooideae (Asparagales) currently comprises five genera, four of which are endemic to southern Africa. Despite their importance in commercial horticulture the evolutionary relationships among the genera are still incompletely understood. This study examines phylogenetic relationships in the subfamily using an expanded molecular sequence dataset from three plastid regions (matK, rbcLa, trnH-psbA) and the first subunit of the nuclear ribosomal internal transcribed spacer (ITS1). Sequence data were analysed using maximum parsimony and Bayesian statistics, and selected morphological traits were mapped onto the molecular phylogeny. Haworthia is confirmed as being polyphyletic, comprising three main clades that largely correlate with current subgeneric circumscriptions. Astroloba and Gasteria are evidently each monophyletic and sister respectively to Astroloba and H. subg. Robustipedunculares. Chortolirion is shown to be deeply nested within Aloe and is formally included in that genus. Aloe itself is clearly polyphyletic, with the dwarf species A. aristata allied to Haworthia subg. Robustipedunculares. The taxonomic implications of these findings are examined but branch support at critical lower nodes is insufficient at this stage to justify implementing major taxonomic changes
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