1,109 research outputs found
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
Tailoring Threshold Voltages of Printed Electrolyte-Gated Field-Effect Transistors by Chromium Doping of Indium Oxide Channels
Printed systems spark immense interest in industry, and for several parts such as solar cells or radio frequency identification antennas, printed products are already available on the market. This has led to intense research; however, printed field-effect transistors (FETs) and logics derived thereof still have not been sufficiently developed to be adapted by industry. Among others, one of the reasons for this is the lack of control of the threshold voltage during production. In this work, we show an approach to adjust the threshold voltage (V) in printed electrolyte-gated FETs (EGFETs) with high accuracy by doping indium-oxide semiconducting channels with chromium. Despite high doping concentrations achieved by a wet chemical process during precursor ink preparation, good on/off-ratios of more than five orders of magnitude could be demonstrated. The synthesis process is simple, inexpensive, and easily scalable and leads to depletion-mode EGFETs, which are fully functional at operation potentials below 2 V and allows us to increase V by approximately 0.5 V
Enhanced magnetocaloric effect in frustrated magnets
The magnetothermodynamics of strongly frustrated classical Heisenberg
antiferromagnets on kagome, garnet, and pyrochlore lattices is examined. The
field induced adiabatic temperature change (dT/dH)_S is significantly larger
for such systems compared to ordinary non-frustrated magnets and also exceeds
the cooling rate of an ideal paramagnet in a wide range of fields. An
enhancement of the magnetocaloric effect is related to presence of a
macroscopic number of soft modes in frustrated magnets below the saturation
field. Theoretical predictions are confirmed with extensive Monte Carlo
simulations.Comment: 7 page
Axion Radiation from Strings
This paper revisits the problem of the string decay contribution to the axion
cosmological energy density. We show that this contribution is proportional to
the average relative increase when axion strings decay of a certain quantity
which we define. We carry out numerical simulations of the
evolution and decay of circular and non-circular string loops, of bent strings
with ends held fixed, and of vortex-antivortex pairs in two dimensions. In the
case of string loops and of vortex-antivortex pairs, decreases by
approximately 20%. In the case of bent strings, remains constant
or increases slightly. Our results imply that the string decay contribution to
the axion energy density is of the same order of magnitude as the
well-understood contribution from vacuum realignment.Comment: 29 pages, 10 figure
Studies of the motion and decay of axion walls bounded by strings
We discuss the appearance at the QCD phase transition, and the subsequent
decay, of axion walls bounded by strings in N=1 axion models. We argue on
intuitive grounds that the main decay mechanism is into barely relativistic
axions. We 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. We find that the
contribution to the cosmological energy density of axions from wall decay is of
the same order of magnitude as that from vacuum realignment, with however large
uncertainties. The velocity dispersion of axions from wall decay is found to be
larger, by a factor or so, than that of axions from vacuum realignment
and string decay. We discuss the implications of this for the formation and
evolution of axion miniclusters and for the direct detection of axion dark
matter on Earth. Finally we discuss the cosmology of axion models with in
which the domain wall problem is solved by introducing a small U(1)
breaking interaction. We find that in this case the walls decay into
gravitational waves.Comment: 37 pages, 10 figures, a minor mistake was corrected, several
references and comments were adde
Relativistic calculations of the K-K charge transfer and K-vacancy production probabilities in low-energy ion-atom collisions
The previously developed technique for evaluation of charge-transfer and
electron-excitation processes in low-energy heavy-ion collisions [I.I. Tupitsyn
et al., Phys. Rev. A 82, 042701(2010)] is extended to collisions of ions with
neutral atoms. The method employs the active electron approximation, in which
only the active electron participates in the charge transfer and excitation
processes while the passive electrons provide the screening DFT potential. The
time-dependent Dirac wave function of the active electron is represented as a
linear combination of atomic-like Dirac-Fock-Sturm orbitals, localized at the
ions (atoms). The screening DFT potential is calculated using the overlapping
densities of each ions (atoms), derived from the atomic orbitals of the passive
electrons. The atomic orbitals are generated by solving numerically the
one-center Dirac-Fock and Dirac-Fock-Sturm equations by means of a
finite-difference approach with the potential taken as the sum of the exact
reference ion (atom) Dirac-Fock potential and of the Coulomb potential from the
other ion within the monopole approximation. The method developed is used to
calculate the K-K charge transfer and K-vacancy production probabilties for the
Ne -- F collisions at the F projectile
energies 130 keV/u and 230 keV/u. The obtained results are compared with
experimental data and other theoretical calculations. The K-K charge transfer
and K-vacancy production probabilities are also calculated for the Xe --
Xe collision.Comment: 16 pages, 4 figure
Vertex importance extension of betweenness centrality algorithm
Variety of real-life structures can be simplified by a graph. Such simplification emphasizes the structure represented by vertices connected via edges. A common method for the analysis of the vertices importance in a network is betweenness centrality. The centrality is computed using the information about the shortest paths that exist in a graph. This approach puts the importance on the edges that connect the vertices. However, not all vertices are equal. Some of them might be more important than others or have more significant influence on the behavior of the network. Therefore, we introduce the modification of the betweenness centrality algorithm that takes into account the vertex importance. This approach allows the further refinement of the betweenness centrality score to fulfill the needs of the network better. We show this idea on an example of the real traffic network. We test the performance of the algorithm on the traffic network data from the city of Bratislava, Slovakia to prove that the inclusion of the modification does not hinder the original algorithm much. We also provide a visualization of the traffic network of the city of Ostrava, the Czech Republic to show the effect of the vertex importance adjustment. The algorithm was parallelized by MPI (http://www.mpi-forum.org/) and was tested on the supercomputer Salomon (https://docs.it4i.cz/) at IT4Innovations National Supercomputing Center, the Czech Republic.808726
Electron gas polarization effect induced by heavy H-like ions of moderate velocities channeled in a silicon crystal
We report on the observation of a strong perturbation of the electron gas
induced by 20 MeV/u U ions and 13 MeV/u Pb ions channeled in
silicon crystals. This collective response (wake effect) in-duces a shift of
the continuum energy level by more than 100 eV, which is observed by means of
Radiative Electron Capture into the K and L-shells of the projectiles. We also
observe an increase of the REC probability by 20-50% relative to the
probability in a non-perturbed electron gas. The energy shift is in agreement
with calculations using the linear response theory, whereas the local electron
density enhancement is much smaller than predicted by the same model. This
shows that, for the small values of the adiabaticity parameter achieved in our
experiments, the density fluctuations are not strongly localized at the
vicinity of the heavy ions
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