6,385 research outputs found
Evidence for antibiotic induced Clostridium perfringens diarrhoea
Clostridium difficile is a well documented
cause of antibiotic associated diarrhoea in
hospitalised patients, but may account for
only approximately 20% of all cases. This
leader reviews the current knowledge and
understanding of the pathogenesis, epidemiology,
and diagnosis of non-food borne
Clostridium perfringens diarrhoea. Although
enterotoxigenic C perfringens has
been implicated in some C difficile negative
cases of antibiotic associated diarrhoea,
C perfringens enterotoxin detection
methods are not part of the routine
laboratory investigation of such cases.
Testing for C perfringens enterotoxin in
faecal samples from patients with antibiotic
associated diarrhoea and sporadic
diarrhoea on a routine basis would have
considerable resource implications.
Therefore, criteria for initiating investigations
and optimum laboratory tests need
to be established. In addition, establishing
the true burden of C perfringens antibiotic
associated diarrhoea is important
before optimum control and treatment
measures can be defined
Alternative potentials for the electromagnetic field
The electromagnetic field can be expressed in terms of two complex potentials
which are related to the Debye potentials. The evolution
equations for these potentials are derived, which are separable either in
parabolic coordinates (leading to the radiation fields) or in radial
coordinates (multipole fields). Potentials corresponding to focused wave fields
as well as plane waves are discussed. A conserved radiation density can be
constructed in terms of these potentials, which is positive (negative) for
positive (negative) helicity radiation.Comment: 13 pages, plainTex, slightly amended version of origina
Interplanetary sector structure, 1962 - 1966
Properties of interplanetary magnetic field observed by IMP-
Solar source of the interplanetary sector structure
Comparison of satellite interplanetary magnetic field observations with photospheric magnetic field and plage structur
Fast Mesh Refinement in Pseudospectral Optimal Control
Mesh refinement in pseudospectral (PS) optimal control is embarrassingly easy
--- simply increase the order of the Lagrange interpolating polynomial and
the mathematics of convergence automates the distribution of the grid points.
Unfortunately, as increases, the condition number of the resulting linear
algebra increases as ; hence, spectral efficiency and accuracy are lost in
practice. In this paper, we advance Birkhoff interpolation concepts over an
arbitrary grid to generate well-conditioned PS optimal control discretizations.
We show that the condition number increases only as in general, but
is independent of for the special case of one of the boundary points being
fixed. Hence, spectral accuracy and efficiency are maintained as increases.
The effectiveness of the resulting fast mesh refinement strategy is
demonstrated by using \underline{polynomials of over a thousandth order} to
solve a low-thrust, long-duration orbit transfer problem.Comment: 27 pages, 12 figures, JGCD April 201
Movie of the interplanetary magnetic field
Description of movie representing IMP-1 MAGNETOMETER observations of interplanetary magnetic fiel
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