2,081 research outputs found
Multi-channel Bethe-Salpeter equation
A general form of multi-channel Bethe-Salpeter equation is considered. In
contradistinction to the hitherto applied approaches, our coupled system of
equations leads to the simultaneous solutions for all relativistic four-point
Green functions (elastic and inelastic) appearing in a given theory. A set of
relations which may be helpful in approximate treatments is given. An example
of extracting useful information from the equations is discussed: we consider
the most general trilinear coupling of N different scalar fields and obtain -
in the ladder approximation - closed expressions for the Regge trajectories and
their couplings to different channels in the vicinity of l = -1. Sum rules and
an example containing non-obvious symmetry are discussed.Comment: 16 pages. Extended version published in JHEP. Uses JHEP.cls
(included
The efficacy of halofantrine in the treatment of acute malaria in nonimmune travelers
A multicenter prospective trial was performed to investigate the efficacy and the tolerability of halofantrine in nonimmune patients with malaria imported from areas with drug-resistant falciparum parasites (mainly Africa). Forty-five of the 74 subjects were treated with a one-day regimen (3 x 500 mg) of halofantrine, and the other 29 received the same regimen with an additional treatment on day 7. In the second group, a 100% efficacy rate was demonstrated, but in the group receiving the one-day regimen, four recrudescences were observed in patients with falciparum malaria. Only five mild adverse reactions were seen, which disappeared spontaneously after the end of the treatment. We conclude that halofantrine is highly effective in curing malaria in nonimmune subjects. The treatment scheme for such persons should include an additional treatment on day 7 for nonimmune individuals. This drug was well tolerated in our patients, indicating that halofantrine will be useful in the treatment of multidrug-resistant malaria in nonimmune persons
Line Shape Diagnositics of Galactic 26Al
The shape of the gamma-ray line from radioactive 26Al, at 1808.7 keV energy in the frame of the decaying isotope,is determined by its kinematics when it decays, typically 106y after its ejection into the interstellar medium from its nucleosyn-thesis source. Three measurements of the line width exist: HEAO-C’s 1982 value of (0 + 3) keV FWHM, the GRIS 1996 valueof (5. 4 ± 1. 3) keV FWHM, and the recent RHESSI value of (2. 0 ± 0. 8) keV FWHM, suggesting either “cold”, “hot”, or “warm”26Al in the ISM. We model the line width as expected from Galactic rotation, expanding supernova ejecta, and/or Wolf-Rayetwinds, and predict a value below 1 keV (FWHM) with plausible assumptions about26Al initial velocities and expansion history.Even though the recent RHESSI measurement reduces the need to explain a broad line corresponding to 540 km s− 1 mean 26Al velocity through extreme assumptions about grain transport of26Al or huge interstellar cavities, our results suggest thatstandard26Al ejection models produce a line on the narrow side of what is observed by RHESSI and INTEGRAL. ImprovedINTEGRAL and RHESSI spatially-resolved line width measurements should help to disentangle the eff ects of Galactic rotationfrom the ISM trajectories of 26A
Disturbance Ecology from nearby Supernovae
Monte Carlo simulations of Galactic Supernovae are carried out to study the
rate of nearby events, which may have a direct effect on Earth's ecology though
ionizing radiation and cosmic ray bombardment. A nearby supernova may have left
a radioactive imprint (60Fe) in recent galactic history.Comment: 7 pages, 1 Fig, to appear in Proc. 11th Workshop on Nuclear
Astrophysics, Ringberg Castle, 2/11-16, 2002; available online at
http://www.mpa-garching.mpg.de/english/greenreports.htm
Non-Equilibrium Large-Scale Membrane Transformations Driven by MinDE Biochemical Reaction Cycles
The MinDE proteins from E. coli have received great attention as a paradigmatic biological pattern-forming system. Recently, it has surfaced that these proteins do not only generate oscillating concentration gradients driven by ATP hydrolysis, but that they can reversibly deform giant vesicles. In order to explore the potential of Min proteins to actually perform mechanical work, we introduce a new model membrane system, flat vesicle stacks on top of a supported lipid bilayer. MinDE oscillations can repeatedly deform these flat vesicles into tubules and promote progressive membrane spreading through membrane adhesion. Dependent on membrane and buffer compositions, Min oscillations further induce robust bud formation. Altogether, we demonstrate that under specific conditions, MinDE self-organization can result in work performed on biomimetic systems and achieve a straightforward mechanochemical coupling between the MinDE biochemical reaction cycle and membrane transformation.We thank MPI‐B Core Facility for assistance in protein purification
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