151 research outputs found
Application of Osteopathic Manipulative Medicine to Ameliorate Sepsis Induced Ileus
Graduate
Basi
Systems Theory as the Foundation for Understanding Systems
As currently used, systems theory is lacking a universally agreed upon definition. The purpose of this paper is to offer a resolution by articulating a formal definition of systems theory. This definition is presented as a unified group of specific propositions which are brought together by way of an axiom set to form a system construct: systems theory. This construct affords systems practitioners and theoreticians with a prescriptive set of axioms by which a system must operate; conversely, any set of entities identified as a system may be characterized by this set of axioms. Given its multidisciplinary theoretical foundation and discipline-agnostic framework, systems theory, as it is presented here, is posited as a general approach to understanding system behavior. © 2013 Wiley Periodicals, Inc
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Unusual sources of fossil micrometeorites deduced from relict chromite in the small size fraction in ~467 Ma old limestone
Extraterrestrial chrome spinel and chromite extracted from the sedimentary rock record are relicts from coarse micrometeorites and rarely meteorites. They are studied to reconstruct the paleoflux of meteorites to the Earth and the collisional history of the asteroid belt. Minor element concentrations of Ti and V, and oxygen isotopic compositions of these relict minerals were used to classify the meteorite type they stem from, and thus to determine the relative meteorite group abundances through time. While coarse sediment-dispersed extraterrestrial chrome-spinel (SEC) grains from ordinary chondrites dominate through the studied time windows in the Phanerozoic, there are exceptions: We have shown that ~467 Ma ago, 1 Ma before the breakup of the L chondrite parent body (LCPB), more than half of the largest (>63 μm diameter) grains were achondritic and originated from differentiated asteroids in contrast to ordinary chondrites which dominated the meteorite flux throughout most of the past 500 Ma. Here, we present a new data set of oxygen isotopic compositions and elemental compositions of 136 grains of a smaller size fraction (32–63 μm) in ~467 Ma old pre-LCPB limestone from the Lynna River section in western Russia, that was previously studied by elemental analysis. Our study constitutes the most comprehensive oxygen isotopic data set of sediment-dispersed extraterrestrial chrome spinel to date. We also introduce a Raman spectroscopy-based method to identify SEC grains and distinguish them from terrestrial chrome spinel with ~97% reliability. We calibrated the Raman method with the established approach using titanium and vanadium concentrations and oxygen isotopic compositions. We find that ordinary chondrites are approximately three times more abundant in the 32–63 μm fraction than achondrites. While abundances of achondrites compared to ordinary chondrites are lower in the 32–63 μm size fraction than in the >63 μm one, achondrites are approximately three times more abundant in the 32–62 μm fraction than they are in the present flux. We find that the sources of SEC grains vary for different grain sizes, mainly as a result of parent body thermal metamorphism. We conclude that the meteorite flux composition ~467 Ma ago ~1 Ma before the breakup of the LCPB was fundamentally different from today and from other time windows studied in the Phanerozoic, but that in contrast to the large size fraction ordinary chondrites dominated the flux in the small size fraction. The high abundance of ordinary chondrites in the studied samples is consistent with the findings based on coarse extraterrestrial chrome-spinel from other time windows
Individual Response to Risk As a Function of Normative Social Pressure: A Pilot Study of Seat Belt Use
The authors attempt to clarify some of the variables that influence whether people act appropriately when a Risk is substantial and subject to individual control. They do so by reporting results of a pilot study of seat belt use. Also, the authors believe their approach to be generalizable to problems such as encouraging people to test for radon, to use condoms to prevent AIDS or to quit smoking
Evidence for H2 Dissociation and Recombination Heat Transport in the Atmosphere of KELT-9b
Phase curve observations provide an opportunity to study the energy budgets of exoplanets by quantifying the amount of heat redistributed from their daysides to their nightsides. Theories of phase curves for hot Jupiters have focused on the balance between radiation and dynamics as the primary parameter controlling heat redistribution. However, recent phase curves have shown deviations from the trends that emerge from this theory, which has led to work on additional processes that may affect hot Jupiter energy budgets. One such process, molecular hydrogen dissociation and recombination, can enhance energy redistribution on ultra-hot Jupiters with temperatures above similar to 2000 K. In order to study the impact of H-2 dissociation on ultra-hot Jupiters, we present a phase curve of KELT-9b observed with the Spitzer Space Telescope at 4.5 mu m. KELT-9b is the hottest known transiting planet, with a 4.5 mu m dayside brightness temperature of 5 sigma confidence. This discrepancy may be due to magnetic effects in the planet's highly ionized atmosphere.This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Universal logic with encoded spin qubits in silicon
Qubits encoded in a decoherence-free subsystem and realized in
exchange-coupled silicon quantum dots are promising candidates for
fault-tolerant quantum computing. Benefits of this approach include excellent
coherence, low control crosstalk, and configurable insensitivity to certain
error sources. Key difficulties are that encoded entangling gates require a
large number of control pulses and high-yielding quantum dot arrays. Here we
show a device made using the single-layer etch-defined gate electrode
architecture that achieves both the required functional yield needed for full
control and the coherence necessary for thousands of calibrated exchange pulses
to be applied. We measure an average two-qubit Clifford fidelity of with randomized benchmarking. We also use interleaved randomized
benchmarking to demonstrate the controlled-NOT gate with
fidelity, SWAP with fidelity, and a specialized entangling
gate that limits spreading of leakage with fidelity
Constraints on axion-like polarization oscillations in the cosmic microwave background with POLARBEAR
Very light pseudoscalar fields, often referred to as axions, are compelling
dark matter candidates and can potentially be detected through their coupling
to the electromagnetic field. Recently a novel detection technique using the
cosmic microwave background (CMB) was proposed, which relies on the fact that
the axion field oscillates at a frequency equal to its mass in appropriate
units, leading to a time-dependent birefringence. For appropriate oscillation
periods this allows the axion field at the telescope to be detected via the
induced sinusoidal oscillation of the CMB linear polarization. We search for
this effect in two years of POLARBEAR data. We do not detect a signal, and
place a median upper limit of on the sinusoid amplitude
for oscillation frequencies between and
, which corresponds to axion masses between and . Under the
assumptions that 1) the axion constitutes all the dark matter and 2) the axion
field amplitude is a Rayleigh-distributed stochastic variable, this translates
to a limit on the axion-photon coupling .Comment: 17 pages, 5 figures, 2 tables. Published in Physical Review
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