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 $\alpha, \beta ,$ 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 $N$ of the Lagrange interpolating polynomial and the mathematics of convergence automates the distribution of the grid points. Unfortunately, as $N$ increases, the condition number of the resulting linear algebra increases as $N^2$; 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 $\sqrt{N}$ in general, but is independent of $N$ for the special case of one of the boundary points being fixed. Hence, spectral accuracy and efficiency are maintained as $N$ 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