1,603 research outputs found
Model independent analysis of nearly L\'evy correlations
A model-independent method for the analysis of the two-particle short-range
correlations is presented, that can be utilized to describe e.g. Bose-Einstein
(HBT), dynamical (ridge) or other correlation functions, that have a nearly
L\'evy or streched exponential shape. For the special case of L\'evy exponent
alpha = 1, the earlier Laguerre expansions are recovered, for the alpha = 2
special case, a new expansion method is obtained for nearly Gaussian
correlation functions. Multi-dimensional L\'evy expansions are also introduced
and their potential application to analyze rigde correlation data is discussed
Rapid deconvolution of low-resolution time-of-flight data using Bayesian inference
The deconvolution of low-resolution time-of-flight data has numerous advantages, including the ability to extract additional information from the experimental data. We augment the well-known Lucy-Richardson deconvolution algorithm using various Bayesian prior distributions and show that a prior of second-differences of the signal outperforms the standard Lucy-Richardson algorithm, accelerating the rate of convergence by more than a factor of four, while preserving the peak amplitude ratios of a similar fraction of the total peaks. A novel stopping criterion and boosting mechanism are implemented to ensure that these methods converge to a similar final entropy and local minima are avoided. Improvement by a factor of two in mass resolution allows more accurate quantification of the spectra. The general method is demonstrated in this paper through the deconvolution of fragmentation peaks of the 2,5-dihydroxybenzoic acid matrix and the benzyltriphenylphosphonium thermometer ion, following femtosecond ultraviolet laser desorption
Clinical experience with amikacin, a new aminoglycoside antibiotic
CITATION: Theron, F. P. & De Kock, M. A. 1977. Clinical experience with amikacin, a new aminoglycoside antibiotic. South African Medical Journal, 51(21):746-8.The original publication is available at http://www.samj.org.za[No abstract available]Publisherâs versio
Is the neutrophil-to-lymphocyte ratio more correlated than C-reactive protein with postoperative complications after major abdominal surgery?
Peer reviewedPublisher PD
Epidemiology of urethral stricture at Tygerberg Hospital
Over a 12-month period, 120 consecutive male patients with confirmed urethral stricture were prospectively studied with regard to the epidemiology of the disease. Specific urethritis is the main aetiological factor (45%) and internal and external trauma account for an alarming 38,3% of cases. The prevalence is highest among 40 - 50-year-old coloured men who have had little schooling, multiple sexual partners and who have a low annual income. The incidence can be reduced by upliftment of moral and educational standards of the local population, and by emphasising the potential dangers of catheterisation and instrumentation to m.edical personnel
Onderzoek naar âLissersâ bij hyacint van start
Het verschijnsel âLissersâ veroorzaakt al enkele jaren achtereen schade in de broei bij hyacint. Oorzaak is een fytoplasma, dat vroeger slechts incidenteel voor kwam. Hierdoor is nog weinig bekend over beschermende maatregelen. PPO start daarom onderzoek naar de bestrijding van de overbrenger (dwergcicade) en bestrijding van het fytoplasma, dat de schade veroorzaakt. Daarbij speelt ook de vraag wanneer de planten besmet worden en wanneer en in welke teeltgebieden van hyacint de cicade aanwezig is
Determining the radial distribution function of water using electron scattering: A key to solution phase chemistry
High energy electron scattering of liquid water (H2O) at near-ambient temperature and pressure was performed in a transmission electron microscope (TEM) to determine the radial distribution of water, which provides information on intra- and intermolecular spatial correlations. A recently developed environmental liquid cell enables formation of a stable water layer, the thickness of which is readily controlled by pressure and flow rate adjustments of a humid air stream passing between two silicon nitride (Si3N4) membranes. The analysis of the scattering data is adapted from the x-ray methodology to account for multiple scattering in the H2O:Si3N4 sandwich layer. For the H2O layer, we obtain oxygenâoxygen (OâO) and oxygenâhydrogen (OâH) peaks at 2.84 Ă
and 1.83 Ă
, respectively, in good agreement with values in the literature. This demonstrates the potential of our approach toward future studies of water-based physics and chemistry in TEMs or electron probes of structural dynamics
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