1,844 research outputs found
Axions from wall decay
We discuss the decay of axion walls bounded by strings and present numerical
simulations of the decay process. In these simulations, the decay happens
immediately, in a time scale of order the light travel time, and the average
energy of the radiated axions is for . is found to increase approximately linearly with
. Extrapolation of this behaviour yields in axion models of interest.Comment: 6 pages, 7 figures, to be published in the Proc. of the 5th IFT Axion
workshop Gainesville FL, Mar 13-15 199
The Rydberg-Atom-Cavity Axion Search
We report on the present progress in development of the dark matter axion
search experiment with Rydberg-atom-cavity detectors in Kyoto, CARRACK I and
CARRACK II. The axion search has been performed with CARRACK I in the 8 % mass
range around , and CARRACK II is now ready for the search in
the wide range . We have also developed
quantum theoretical calculations on the axion-photon-atom system in the
resonant cavity in order to estimate precisely the detection sensitivity for
the axion signal. Some essential features on the axion-photon-atom interaction
are clarified, which provide the optimum experimental setup for the axion
search.Comment: 8 pages, 2 figures, Invited talk presented at the Dark2000,
Heidelberg, Germany,10-15 July, 200
Can one predict DNA Transcription Start Sites by studying bubbles?
It has been speculated that bubble formation of several base-pairs due to
thermal fluctuations is indicatory for biological active sites. Recent
evidence, based on experiments and molecular dynamics (MD) simulations using
the Peyrard-Bishop-Dauxois model, seems to point in this direction. However,
sufficiently large bubbles appear only seldom which makes an accurate
calculation difficult even for minimal models. In this letter, we introduce a
new method that is orders of magnitude faster than MD. Using this method we
show that the present evidence is unsubstantiated.Comment: 4 pages, 3 figures, accepted for publication in physical review
letter
Relativistic calculations of the x-ray emission following the Xe-Bi collision
We study the x-ray emission following the collision of a Bi ion with
a neutral Xe atom at the projectile energy 70 MeV/u. The collisional and
post-collisional processes are treated separately. The probabilities of various
many-electron processes at the collision are calculated within a relativistic
independent electron model using the coupled-channel approach with atomic-like
Dirac-Fock-Sturm orbitals. The analysis of the post-collisional processes
resulting in the x-ray emission is based on the fluorescence yields, the
radiation and Auger decay rates, and allows to derive intensities of the x-ray
emission and compare them with experimental data. A reasonable agreement
between the theoretical results and the recent experimental data is observed.
The role of the relativistic effects is investigated.Comment: 11 figures, 2 table
Relativistic calculations of the charge-transfer probabilities and cross sections for low-energy collisions of H-like ions with bare nuclei
A new method for solving the time-dependent two-center Dirac equation is
developed. The time-dependent Dirac wave function is represented as a sum of
atomic-like Dirac-Sturm orbitals, localized at the ions. The atomic orbitals
are obtained by solving numerically the finite-difference one-center Dirac and
Dirac-Sturm equations with the potential which is the sum of the exact
reference-nucleus potential and a monopole-approximation potential from the
other nucleus. An original procedure to calculate the two-center integrals with
these orbitals is proposed. The approach is tested by calculations of the
charge transfer and ionization cross sections for the H(1s)--proton collisions
at proton energies from 1 keV to 100 keV. The obtained results are compared
with related experimental and other theoretical data. To investigate the role
of the relativistic effects, the charge transfer cross sections for the
Ne^{9+}(1s)--Ne^{10+} (at energies from 0.1 to 10 MeV/u) and
U^{91+}(1s)--U^{92+} (at energies from 6 to 10 MeV/u) collisions are calculated
in both relativistic and nonrelativistic cases.Comment: 39 pages, 6 tables, 7 figure
Gonococcal osteomyelitis in a pediatric patient with disseminated gonococcal infection: Implications for antimicrobial management
© 2020 The Authors We report a case of a female teenager with gonococcal septic arthritis of the right shoulder that also caused osteomyelitis of the humeral head. Infection with Neisseria gonorrhoeae is a frequently diagnosed sexually transmitted infection in the sexually active teenage population and disseminated gonococcal infection (DGI) is the most common systemic manifestation of acute gonorrhea. DGI commonly involves acute arthritis, tenosynovitis and dermatitis with less common complications of endocarditis, hepatitis and meningitis. In contrast, osteomyelitis has only rarely been reported as a result of gonococcal infection. Clinicians need to be aware of this unusual manifestation of DGI as a prolonged duration of antimicrobial treatment may be needed to assure complete resolution of this infection
Reduction of heat sink common-mode currents in switching mode power supply circuits
In this paper, a new filter design for a heat sink is presented. The
parasitic couplings between electric power devices and the heat sink are
responsible for common-mode currents. The main focus is on the reduction of
these currents to reduce the heat sink radiation. For this purpose a new
filter design is proposed. In addition, experimental results are shown to
validate the proposed filter
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