2,721 research outputs found

    Feasibility of a resonance-based Planet Nine search

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    It has been proposed that mean motion resonances (MMRs) between Planet Nine and distant objects of the scattered disk might inform the semimajor axis and instantaneous position of Planet Nine. Within the context of this hypothesis, the specific distribution of occupied MMRs largely determines the available constraints. Here we characterize the behavior of scattered Kuiper Belt objects arising in the presence of an eccentric Planet Nine (e9∈0.1e_9 \in 0.1, 0.70.7), focusing on relative sizes of populations occupying particular commensurabilities. Highlighting the challenge of predicting the exact MMR of a given object, we find that the majority of resonant test particles have period ratios with Planet Nine other than those of the form P9/P=N/1P_9/P=N/1, N/2N/2 (N∈Z+)(N \in \mathbb{Z}^+). Taking into account the updated prior distribution of MMRs outlined in this work, we find that the close spacing of high-order resonances, as well as chaotic transport, preclude resonance-based Planet Nine constraints from current observational data.Comment: 6 pages, 7 figure

    Censorship By Media Elites Will Ultimately Threaten the Republic

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    Transitioning Non-Traditional Students To An Undergraduate Business Program

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    This paper reports experiences of non-traditional students in a specially designed section of seminar course which was primarily designed for first-year traditional business students.  The College of Business’s BSN101, Foundations of Business Administration (FBA), is designed to serves as a course to assist the students with transitioning into the business program.  Typical traditional classes have enrollments of about 80 students. The special section for non-traditional students had seven students, 24 years of age or older, who were returning to undergraduate business school.  This paper reports results of the implementation of the new program design in the FBA classes. Results are important not only to the College of Business, but also to the other Colleges as interest in first-year seminar courses and better serving the needs of non-traditional student increases. Currently, the University Retention Committee and the First-Year Seminar Sub-Committee are exploring the possibility of implementing a first-year seminar courses in the College of Arts and Sciences and the College of Education and Human Services to be recommended to the Provost.  Data collected for the experimental section in the study reported here will support decision-making regarding new seminar courses

    Laboratory Measurements Of White Dwarf Photospheric Spectral Lines: H Beta

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    We spectroscopically measure multiple hydrogen Balmer line profiles from laboratory plasmas to investigate the theoretical line profiles used in white dwarf (WD) atmosphere models. X-ray radiation produced at the Z Pulsed Power Facility at Sandia National Laboratories initiates plasma formation in a hydrogen-filled gas cell, replicating WD photospheric conditions. Here we present time-resolved measurements of H beta and fit this line using different theoretical line profiles to diagnose electron density, n(e), and n = 2 level population, n2. Aided by synthetic tests, we characterize the validity of our diagnostic method for this experimental platform. During a single experiment, we infer a continuous range of electron densities increasing from n(e) similar to 4 to similar to 30 x 10(16) cm(-3) throughout a 120-ns evolution of our plasma. Also, we observe n(2) to be initially elevated with respect to local thermodynamic equilibrium (LTE); it then equilibrates within similar to 55 ns to become consistent with LTE. This supports our electrontemperature determination of T-e similar to 1.3 eV (similar to 15,000 K) after this time. At n(e) greater than or similar to 10(17) cm(-3), we find that computer-simulation-based line-profile calculations provide better fits (lower reduced chi(2)) than the line profiles currently used in the WD astronomy community. The inferred conditions, however, are in good quantitative agreement. This work establishes an experimental foundation for the future investigation of relative shapes and strengths between different hydrogen Balmer lines.Laboratory Directed Research and Development programUnited States Department of Energy DE-AC04-94AL85000, DE-SC0010623National Science Foundation DGE-1110007Astronom

    Ashfall Tephra in the Ogallala Group of the Great Plains: Characteristics and Significance

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    The Miocene Ogallala Group blankets the Great Plains east of the Rocky Mountains. This sheet of largely fluvial deposits, lying downwind of major silicic volcanic fields to the west, was ideally located to receive and preserve tephra from these fields. This investigation brings modern methods of tephrochronlogy to bear on the age and identity of Ogallala tephra. Results indicate that ~40 separate tephra layers, ranging in age from ~16.5–5.0 Ma, in the Ogallala. Most tephra came from Yellowstone hotspot sources. The relative frequency of hotspot tephra in the Ogallala matches that in more proximal regions to the west with peak intensities in the intervals ~16.5−15 Ma nd ~13.0−8.5 Ma. About 30 of the Ogallala tephra are correlated with tephra of known age the the Basin and Range to the west. Using the ages of correlative tephra to the west insight into the age of the Ogallala, the correlation of Ogallala tephra from region to region in the Great Plains, and sedimentation rates within the Ogallala. In the Ogallala sedimentation rates vary. The rates are lowest (3–9 m/Ma) in the Cap Rock Mbr. of the Ash Hollow Fm. along the Niobrara River and in undifferentiated Ogallala strata and in the undifferentiated Ogalala Gp. in NW Kansas. Rates of 40–80 m/Ma characterize the Valentine Fm. beneath the Cap Rock Mbr. Finally, one tephra, the 11.37 Ma Cougar Point Tuff XI, is recognized at 6 localies. This key horizon provides the first detailed structure contours within the Ogallala. These contours show a sharply increasing slope of the Ogallala west of 101° W that reflects the post–6 Ma tilt along the western edge of the Ogallala. East of 101º W the gradients mirror the gradients of the major rivers (1.3 to 1.6 m/km.). West of 101º W gradients increase and reach a maximun of 4.6 m/km at the crest of the Gangplank

    Ashfall Tephra in the Ogallala Group of the Great Plains: Characteristics and Significance

    Get PDF
    The Miocene Ogallala Group blankets the Great Plains east of the Rocky Mountains. This sheet of largely fluvial deposits, lying downwind of major silicic volcanic fields to the west, was ideally located to receive and preserve tephra from these fields. This investigation brings modern methods of tephrochronlogy to bear on the age and identity of Ogallala tephra. Results indicate that ~40 separate tephra layers, ranging in age from ~16.5–5.0 Ma, in the Ogallala. Most tephra came from Yellowstone hotspot sources. The relative frequency of hotspot tephra in the Ogallala matches that in more proximal regions to the west with peak intensities in the intervals ~16.5−15 Ma nd ~13.0−8.5 Ma. About 30 of the Ogallala tephra are correlated with tephra of known age the the Basin and Range to the west. Using the ages of correlative tephra to the west insight into the age of the Ogallala, the correlation of Ogallala tephra from region to region in the Great Plains, and sedimentation rates within the Ogallala. In the Ogallala sedimentation rates vary. The rates are lowest (3–9 m/Ma) in the Cap Rock Mbr. of the Ash Hollow Fm. along the Niobrara River and in undifferentiated Ogallala strata and in the undifferentiated Ogalala Gp. in NW Kansas. Rates of 40–80 m/Ma characterize the Valentine Fm. beneath the Cap Rock Mbr. Finally, one tephra, the 11.37 Ma Cougar Point Tuff XI, is recognized at 6 localies. This key horizon provides the first detailed structure contours within the Ogallala. These contours show a sharply increasing slope of the Ogallala west of 101° W that reflects the post–6 Ma tilt along the western edge of the Ogallala. East of 101º W the gradients mirror the gradients of the major rivers (1.3 to 1.6 m/km.). West of 101º W gradients increase and reach a maximun of 4.6 m/km at the crest of the Gangplank

    A method of combating infection

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