4,447 research outputs found
Earth Matter Effects in Detection of Supernova Neutrinos
We calculated the matter effect, including both the Earth and supernova, on
the detection of neutrinos from type II supernovae at the proposed Daya Bay
reactor neutrino experiment. It is found that apart from the dependence on the
flip probability P_H inside the supernova and the mass hierarchy of neutrinos,
the amount of the Earth matter effect depends on the direction of the incoming
supernova neutrinos, and reaches the biggest value when the incident angle of
neutrinos is around 93^\circ. In the reaction channel \bar{\nu}_e + p --> e^+ +
n the Earth matter effect can be as big as about 12%. For other detection
processes the amount of the Earth matter effect is a few per cent.Comment: 13 pages, 5 figure
Potential formulation of the dispersion relation for a uniform, magnetized plasma with stationary ions in terms of a vector phasor
The derivation of the helicon dispersion relation for a uniform plasma with
stationary ions subject to a constant background magnetic field is reexamined
in terms of the potential formulation of electrodynamics. Under the same
conditions considered by the standard derivation, the nonlinear self-coupling
between the perturbed electron flow and the potential it generates is
addressed. The plane wave solution for general propagation vector is determined
for all frequencies and expressed in terms of a vector phasor. The behavior of
the solution as described in vacuum units depends upon the ratio of
conductivity to the magnitude of the background field. Only at low conductivity
and below the cyclotron frequency can significant propagation occur as
determined by the ratio of skin depth to wavelength.Comment: 10 pages, 6 figures, major revision, final version, to appear in Po
Chronostratigraphy of Miocene Strata in the Berkeley Hills (California Coast Ranges, USA) and the Arrival of the San Andreas Transform Boundary
Miocene strata of the Claremont, Orinda, and Moraga formations of the Berkeley Hills (California Coast Ranges, USA) record sedimentation and volcanism during the passage of the Mendocino triple junction and early evolution of the San Andreas fault system. Detrital zircon laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) age spectra indicate a change in sedimentary provenance between the marine Claremont formation (Monterey Group) and the terrestrial Orinda and Moraga Formations associated with uplift of Franciscan Complex lithologies. A sandstone from the Claremont formation produced a detrital zircon chemical abrasion–isotope dilution–thermal ionization mass spectrometry (CA-ID-TIMS) maximum depositional age of 13.298 ± 0.046 Ma, indicating younger Claremont deposition than previously interpreted. A trachydacite tuff clast within the uppermost Orinda Formation yielded a CA-ID-TIMS U-Pb zircon date of 10.094 ± 0.018 Ma, and a dacitic tuff within the Moraga Formation produced a CA-ID-TIMS U-Pb zircon date of 9.974 ± 0.014 Ma. These results indicate rapid progression from subsidence in which deep-water siliceous sediments of the Claremont formation were deposited to uplift that was followed by subsidence during deposition of terrestrial sediments of the Orinda Formation and subsequent eruption of the Moraga Formation volcanics. We associate the Orinda tuff clast and Moraga volcanics with slab-gap volcanism that followed the passage of the Mendocino triple junction. Given the necessary time lag between triple junction passage and the removal of the slab that led to this volcanism, subsidence associated with ca. 13 Ma Claremont sedimentation and subsequent Orinda to Moraga deposition can be attributed to basin formation along the newly arrived transform boundary
Using an Augmented Reality App for Flight Training
As the global demand for aviation pilots continues to drastically increase, flight schools are experiencing a large influx of ab-initio flight students. Such flight training programs are seeking innovative, cutting-edge technologies to support these students and expedite their flight training. The ARAir app, a custom app developed by our team, was designed for ab-initio pilots training at the Embry-Riddle Prescott campus. The initial implementation in Spring 2021 included phonetic alphabet practice and strategic radiotelephony that allows students to practice in a self-paced environment with immediate corrective feedback at various levels of complexity. Students can compete against themselves to improve phonetic alphabet knowledge, create initial radio transmissions, read back ATC instructions, and manipulate an aircraft to the correct intended location at the KPRC airport. Based on the survey and interview feedback collected after the initial implementation, additional support for checklist memorization using the Augmented Reality (AR) feature was added to the ARAir app. This presentation will report students’ learning experience with the improved ARAir in the second implementation in Spring 2022
High-fidelity preparation, gates, memory and readout of a trapped-ion quantum bit
We implement all single-qubit operations with fidelities significantly above
the minimum threshold required for fault-tolerant quantum computing, using a
trapped-ion qubit stored in hyperfine "atomic clock" states of Ca.
We measure a combined qubit state preparation and single-shot readout fidelity
of 99.93%, a memory coherence time of seconds, and an average
single-qubit gate fidelity of 99.9999%. These results are achieved in a
room-temperature microfabricated surface trap, without the use of magnetic
field shielding or dynamic decoupling techniques to overcome technical noise.Comment: Supplementary Information included. 6 nines, 7 figures, 8 page
Star Formation in M51 Triggered by Galaxy Interaction
We have mapped the inner 360'' regions of M51 in the 158micron [CII] line at
55'' spatial resolution using the Far-infrared Imaging Fabry-Perot
Interferometer (FIFI) on the Kuiper Airborne Observatory (KAO). The emission is
peaked at the nucleus, but is detectable over the entire region mapped, which
covers much of the optical disk of the galaxy. There are also two strong
secondary peaks at ~43% to 70% of the nuclear value located roughly 120'' to
the north-east, and south-west of the nucleus. These secondary peaks are at the
same distance from the nucleus as the corotation radius of the density wave
pattern. The density wave also terminates at this location, and the outlying
spiral structure is attributed to material clumping due to the interaction
between M51 and NGC5195. This orbit crowding results in cloud-cloud collisions,
stimulating star formation, that we see as enhanced [CII] line emission. The
[CII] emission at the peaks originates mainly from photodissociation regions
(PDRs) formed on the surfaces of molecular clouds that are exposed to OB
starlight, so that these [CII] peaks trace star formation peaks in M51. The
total mass of [CII] emitting photodissociated gas is ~2.6x10^{8} M_{sun}, or
about 2% of the molecular gas as estimated from its CO(1-0) line emission. At
the peak [CII] positions, the PDR gas mass to total gas mass fraction is
somewhat higher, 3-17%, and at the secondary peaks the mass fraction of the
[CII] emitting photodissociated gas can be as high as 72% of the molecular
mass.... (continued)Comment: 14 pages, 6 figures, Accepted in ApJ (for higher resolution figures
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Propagation of a Solitary Fission Wave
Reaction-diffusion phenomena are encountered in an astonishing array of natural systems. Under the right conditions, self stabilizing reaction waves can arise that will propagate at constant velocity. Numerical studies have shown that fission waves of this type are also possible and that they exhibit soliton like properties. Here, we derive the conditions required for a solitary fission wave to propagate at constant velocity. The results place strict conditions on the shapes of the flux, diffusive, and reactive profiles that would be required for such a phenomenon to persist, and this condition would apply to other reaction diffusion phenomena as well. Numerical simulations are used to confirm the results and show that solitary fission waves fall into a bistable class of reaction diffusion phenomena. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4729927]United States Nuclear Regulatory Commission NRC-38-08-946Mechanical Engineerin
Rapid One-Step Selection Method for Generating Nucleic Acid Aptamers: Development of a DNA Aptamer against alpha-Bungarotoxin
Background: Nucleic acids based therapeutic approaches have gained significant interest in recent years towards the development of therapeutics against many diseases. Recently, research on aptamers led to the marketing of Macugen (R), an inhibitor of vascular endothelial growth factor (VEGF) for the treatment of age related macular degeneration (AMD). Aptamer technology may prove useful as a therapeutic alternative against an array of human maladies. Considering the increased interest in aptamer technology globally that rival antibody mediated therapeutic approaches, a simplified selection, possibly in one-step, technique is required for developing aptamers in limited time period
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