Forward-backward multiplicity correlations in σ+ p,K + p andpp collisions at 250 GeV/c

Forward-backward multiplicity correlations in σ⁺,K ⁺ p andpp collisions at 250 GeV/c ( \(\sqrt s \) =22 GeV) are given for all charges and for the different charge combinations. The correlations are found to be caused predominantly by centrally produced particles. It is demonstrated that this result is an agreement with observations at the ISR and the CERNp \(\bar p\) -Collider. The results are compared to expectations from LUND, DPM and FRITIOF Monte Carlo models and a geometrical picture relating correlations in hadron-hadron collisions toe ⁺ e ^? data in terms of impact parameters is tested.     

Spatial fluctuations in reaction-limited aggregation

A general method is used for describing reaction-diffusion systems, namely van Kampen's method of compounding moments, to study the spatial fluctuations in reaction-limited aggregation processes. The general formalism used here and in subsequent publications is developed. Then a particular model is considered that is of special interest, since it describes the occurrence of a phase transition (gelation). The corresponding rate constants for the reaction between two clusters of sizei and sizej areK _ij=ij (i, j=1, 2,). For thediffusion constants D _j of clusters of sizej the following class of models is considered:D _j=D if 1Js andD _j=0 ifj>s. The casess= ands< are studied separately. For the models= the equal-time and the two-time correlation functions are calculated; this modelbreaks down at the gel point. The breakdown is characterized by a divergence of the density fluctuations, and is caused by the large mobility of large clusters. For all models withs< the density fluctuations remain finite att _c, and the equal-time correlation functions in the pre- and in the post-gel stage are calculated. Many explicit and asymptotic results are given. From the exact solution the upper critical dimension in this gelling model isd _c=2.     

A neutral gas model for electron swarms

A BGK-type Boltzmann equation for a neutral gas is considered as a model for electron swarms, because the gas and the electron Boltzmann equation have a common diffusion approximation. Both full- and half-range theory are developed using orthogonality methods of solution. Preliminary comparisons with diffusion theory are presented.     

Urinary excretion of methylated purines in man and in the rat after the administration of theophylline

Chromatographic characteristics of urinary metabolites of theophylline were studied by two-dimensional thin-layer chromatography, high-performance liquid chromatography and gas chromatography--mass spectrometry. Quantitative date for the urinary metabolites of theophylline in asthmatic children are given. It was shown that 1,3-dimethyluric acid is the predominant excretory product. In addition, smaller amounts of 1-methyluric acid, 3-methylxanthine and unchanged theophylline were found. Excretory patterns after theophylline ingestion before and during the administration of allopurinol in asthma patients and in rats suggest the existence of three metabolic pathways of theophylline. The administration of this drug to a patient with xanthine oxidase of theophylline. The administration of this drug to a patient with xanthine oxidase deficiency resulted in the excretion of 1-methyluric acid in addition to 1,3-dimethyluric acid, 3-methylxanthine, 1-methylxanthine and unchanged theophylline. It was concluded that in man the oxidation of theophylline is not catalysed by xanthine oxidase.     

Lattice dynamics of tetracyanoethylene

Lattice dynamics calculations for both crystalline forms of tetracyanoethylene are presented. The comparison of the calculated static and dynamical properties with the experimental data, leads us to suggest an improved parameter set for the “6-exp” potential function for crystals with cyano groups.     

Systematic computer-aided interpretation of infrared and raman vibrational spectra based on the crise program

The CRISE computer program is used to correlate wavenumber regions and 6 structural elements containing carbon, hydrogen and oxygen on the basis of 2 standard files with 549 infrared and Raman spectra. The degree of correlation, including score percentages and interfering percentages, is established for different types of intervals in relation to various intensity thresholds. Specific regions (score 100%, interference 0%) proved to be rare, whereas pseudo-specific regions (score < 100%, interference 0%) are normally present. The usefulness of selective regions (score 100%, interference > 0%) is doubtful. The infrared and Raman results for a structural element can differ appreciably, yet neither technique is clearly superior for interpretative purposes.