Structure of final states with a high transverse momentum π0 in proton-proton collisions

We present a study of the final state structure in proton-proton collisions (√s = 53 GeV) where a large transverse momentum π⁰ (p_t > 2 GeV/c) is produced at an angle of 90°. Charged secondaries have been detected and momentum analysed in the split field magnet detector at the CERN Intersecting Storage Rings. The large angular coverage of this detector extends over ±2.5 units of rapidity and ±30° of azimuth with respect to the trigger π⁰, both towards and away from it. In each of these directions, where we observe similar strong correlations, we present charged particle distributions, in rapidity and momentum. In the hemisphere containing the trigger π⁰ we have measured the cross section for inclusive production of large transverse momentum ?^± mesons. In the opposite hemisphere the data exhibit several features predicted by hard scattering quark-parton models: coplanarity and short-range rapidity correlation for the large transverse momentum secondaries as well as a transverse momentum sharing distribution similar to that observed in deep inelastic electro-production and in e⁺e^? collisions.     

Monotonicity of quadrature formulae of Gauss type and comparison theorems for monosplines

Summary This paper deals with quadrature formulae of Gauss type corresponding to subspaces of spline functionsS _{m–1, k} of degreem–1 withk fixed knots. We shall show monotonicity of the quadrature formulae for functions which are contained in the so-called convexity cone ofS _m–1,k Moreover, we apply these results to monosplines and establish comparison theorems for these splines.     

The relevance of ester exchange in oxalacetic esters to the decarbonmonoxylation reaction

Oxalacetic esters undergo ester exchange at 120°C, at which temperature loss of CO does not occur. A new mechanism is proposed for the decarbonmonoxylation reaction.     

Uniqueness of analytic continuation: Necessary and sufficient conditions

Necessary and sufficient conditions for uniqueness of analytic continuation are investigated for a system of m ? 1 first-order linear homogeneous partial differential equations in one unknown, with complex-valued $\text{b}$^∞ coefficients, in some connected open subset of $\text{R}$^k, k ? 2. The type of system considered is one for which there exists a real k-dimensional, $\text{b}$^∞, connected C-R submanifold M^k of $\text{C}$ⁿ, for k, n ? 2, such that the system may be identified with the induced Cauchy-Riemann operators on M^k. The question of uniqueness of analytic continuation for a system of partial differential equations is thus transformed to the question of uniqueness of analytic continuation for C-R functions on the manifold M^k ? Cⁿ. Under the assumption that the Levi algebra of M^k has constant dimension, it is shown that if the excess dimension of this algebra is maximal at every point, then M^k has the property of uniqueness of analytic continuation for its C-R functions. Conversely, under certain mild conditions, it is shown that if M^k has the property of uniqueness of analytic continuation for all $\text{b}$^∞ C-R functions, and if the Levi algebra has constant dimension on all of M^k, then the excess dimension must be maximal at every point of M^k.     

Time-gated microscopic energy transfer measurements for probing mitochondrial metabolism

Spectroscopic and microscopic methods for probing mitochondrial malfunction were established using cultivated endothelial cells from the calf aorta and various inhibitors of the respiratory chain, which is located at the inner mitochondrial membrane. Time-gated fluorescence spectroscopy was used to measure autofluorescence of the coenzyme NADH as well as “energy transfer efficacy” from excited NADH molecules (energy donor) to the mitochondrial marker rhodamine-123 (energy acceptor). Autofluorescence usually exhibited a weak increase after specific inhibition of enzyme complexes of the respiratory chain. In contrast, a pronounced increase in energy transfer efficacy was observed after inhibition of the same enzyme complexes. The detection of donor (NADH) and acceptor (R123) fluorescence in different nanosecond time gates following the exciting laser pulses enhances selectivity and improves quantification of energy transfer measurements. Therefore, timegated energy transfer spectroscopy is suggested to be an appropriate tool for probing mitochondrial malfunction.     

On a wave equation with a cubic convolution

We study the well-posedness of the Cauchy problem and the asymptotic behavior of solutions of the nonlinear wave equation $\text{u}{}_{\mathrm{tt}}\text{? Δu + m}{}^2\text{+ u(V 1 u}{}^2\text{) = 0}$ in Euclidean space.     

Weak descartes systems in generalized spline spaces

A class of generalized spline spaces is introduced for which a basis of functions with local support is constructed by using a recursion relation. It is shown that this basis forms a weak Descartes system. Moreover, an interpolation property is given.     

An investigation into the role of metastable argon atoms in the afterglow plasma of a low pressure discharge

An investigation into the behaviour of metastable argon atoms in a low pressure (250 Pa) pulsed electrical discharge was undertaken in an effort to find the cause of the persisting emission from sputtered metal atoms in the afterglow of an atomic fluorimeter. Results obtained by time-resolved emission and absorption measurements of several argon and copper spectral lines indicate that low energy electrons in the afterglow are converted to high energy electrons via the recombination of electrons with argon ions and the subsequent collisions of pairs of metastable argon atoms. The high energy electrons excite the sputtered metal atoms to give rise to a slow decaying emission tail in the afterglow. A probable change in the electron energy distribution in the afterglow may also have an effect on the observed emission. This phenomenon may be reduced by the use of a suitable quenching gas.     

Displacement-cyclization reactions of mono-substituted hydrazines with chloronitrobenzenes and chloronitropyrimidines. New routes to 8-azapurine and benzopyrazole derivatives

Reactions of different chloronitrobenzenes and chloronitropyrimidines with monosubstituted hydrazines, R-NHNH₂, where R is methyl, carbomethoxy and phenyl, are described. The reactivity of these hydrazines in displacement-ortho substituent cyclizations varies substantially, depending on the nature of the aromatic substrate and the hydrazine R group. New routes to 8-azapurine and benzopyrazole derivatives are decribed.     

The total synthesis of (−)-mesembranone

Elaboration of the novel chiral amide acetal (S)-$\text{4}$, constitutes the first total synthesis of natural (?)-mesembranone.