Nuclear stopping from 0.09A to 1.93A GeV and its correlation to flow

We present a complete systematics (excitation functions and system-size dependences) of global stopping and side flow for heavy ion reactions in the energy range between 0.09A and 1.93A GeV. For the heaviest system, Au+Au, we observe a plateau of maximal stopping extending from about 0.2A to 0.8A GeV with a fast drop on both sides. The degree of stopping, which is shown to remain significantly below the expectations of a full stopping scenario, is found to be highly correlated to the amount of side flow.     

Thermal characterization of hair using TG-MS combined thermoanalytical technique

Four amino acids and four different hair samples were studied in order to get information about the decomposition of human hair, using combined (TG-MS) and DSC techniques. The thermal stability of the investigated amino acid samples was different. Since they contain identical functional groups (-NH₂, -COOH) some common mass/charge units were identified. However, due to their different chemical composition remarkable differences have also been obtained. The results of the investigation of the amino acids were helpful to study the thermal fragmentation of the hair samples. In our experiments, the effect of the heating rates was also studied. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermal behaviour of complexes of antipyrine derivatives II

Parent and mixed ligand complexes of cobalt(II) and copper(II) ions with N,N-bis-(4-antipyrylmethyl)piperazine or N,N-tetra(4-antipyryl-methyl)-1,2-diaminoethane or/and imidazole as ligand and ClO ₄ ^– or SCN^– as counterion were synthesised and their thermal behaviour was investigated.This work was performed in the framework of cooperation between the Hungarian Academy of Sciences and Romanian Academy and was supported financially, in part, by the Hungarian Scientific Research Foundation (OTKA T 029554).     

Effect of UVA radiation on membrane fluidity and radical decay in human fibroblasts as detected by spin labeled stearic acids

The ultraviolet A (UVA) radiation component of sunlight (320-400 nm) has been shown to be a source of oxidative stress to cells via generation of reactive oxygen species. We report here some consequences of the UVA irradiation on cell membranes detected by electron paramagnetic resonance (EPR) spectroscopy. Paramagnetic nitroxide derivatives of stearic acid bearing the monitoring group at different depths in the hydrocarbon chain were incorporated into human fibroblasts membranes to analyze two main characteristics: kinetics of the nitroxide reduction and membrane fluidity. These two characteristics were compared for control and UVA-irradiated (0-250 kJ/m(2)) cells. The term relative redox capacity (RRC) was introduced to characterize and to compare free radical reduction measured by EPR with some well-known viability/clonogenicity tests. Our results showed that UVA-irradiation produces a more rigid membrane structure, especially at higher doses. Furthermore, we found that trends agree in survival measured by neutral red (NR), trypan blue (TB), and clonogenic efficiency compared with RRC values measured by EPR for low and medium exposure doses. Above 100 kJ/m(2), differences between these tests were observed. Antioxidant effect was modeled by alpha-tocopherol-acetate treatment of the cells before UVA irradiation. While NR, TB and clonogenicity tests showed protection at the highest UVA doses (>100 kJ/m(2)), results obtained with EPR measurements, both membrane fluidity and kinetics, or using MTT test did not exhibit this protective effect.     

Monitoring nanoparticle formation during laser ablation of graphite in an atmospheric-pressure ambient

Excimer laser ablation of highly oriented pyrolytic graphite (HOPG) was performed at atmospheric pressure in an N₂ and in an air ambient. During the ablation, nanoparticles condensed from the material ejecta, and their size distribution was monitored in the gas phase by a Differential Mobility Analyzer (DMA) in combination with a Condensation Particle Counter (CPC). Size distributions obtained at different laser repetition rates revealed that the interaction between subsequent laser pulses and formed particles became significant above 15 Hz. This interaction resulted in laser heating, leading to considerable evaporation and a decrease in the size of the particles. X-ray photoelectron spectroscopy revealed that approximately 8% nitrogen was incorporated into the CN_x particles generated in the N₂ ambient, and that the nitrogen was mostly bonded to sp³-hybridized carbon. Monodisperse particles were also deposited and were analyzed by means of Raman spectroscopy to monitor size-induced effects. PACS 81.07.-b; 61.46.+w; 79.70.+q     

Absolute resonance strengths in the $^{6,7}Li(\alpha, \gamma)^{10,11}B$ reactions

The absolute strengths of the keV resonance in the reaction and of the keV resonance in the reaction have been measured to meV and meV, respectively, in good agreement with previous values. These resonances can be used to measure the absolute acceptance of the recoil separator ERNA to a precision of about 10%.Received: 12 December 2003, Revised: 10 February 2004, Published online: 3 August 2004PACS: 24.30.-v Resonance reactions - 25.40.Lw Radiative capture - 26.20. + f Hydrostatic stellar nucleosynthesis     

Multiphonon vibrations at high angular momentum in 182 Os

Evidence is presented for multiphonon excitations based on a high-spin (25 Planck) intrinsic state in the deformed nucleus 182 Os. Angular momentum generation by this mode competes with collective rotation. The experimental data are compared with tilted-axis cranking calculations, supporting the vibrational interpretation. However, the lower experimental energies provide evidence that more complex interactions of states are playing a role.     

Finite temperature spectral function of the σ meson from large <Emphasis Type="Italic">N</Emphasis> expansion

The spectral function of the scalar-isoscalar channel of the O(N) symmetric linear σ model is studied in the broken symmetry phase. The investigation is based on the leading order evaluation of the self-energy in the limit of large number of Goldstone bosons. We describe its temperature-dependent variation in the whole low temperature phase. This variation closely reflects the trajectory of the scalar-isoscalar quasi-particle pole. In the model with no explicit chiral symmetry breaking, we studied also the corresponding dynamical exponent near the critical point.     

On 1-Blocking Sets in PG(n,q), n ≥ 3

In this article we study minimal1-blocking sets in finite projective spaces _PG(n,q),n 3. We prove that in PG(n,q ²),q = p ^h , p prime, p > 3,h 1, the second smallest minimal 1-blockingsets are the second smallest minimal blocking sets, w.r.t.lines, in a plane of PG(n,q ²). We also study minimal1-blocking sets in PG(n,q ³), n 3, q = p ^h, p prime, p > 3,q 5, and prove that the minimal 1-blockingsets of cardinality at most q 3 + q ² + q + ¹ are eithera minimal blocking set in a plane or a subgeometry PG(3,q).     

Petrov Types of Slowly Rotating Fluid Balls

Circularly rotating axisymmetric perfect fluid space-times are investigated to second order in the small angular velocity. The conditions of various special Petrov types are solved in a comoving tetrad formalism. A number of theorems are stated on the possible Petrov types of various fluid models. It is shown that Petrov type II solutions must reduce to the de Sitter spacetime in the static limit. Two space-times with a physically satisfactory energy-momentum tensor are investigated in detail. For the rotating incompressible fluid, it is proven that the Petrov type cannot be D. The equation of the rotation function can be solved for the Tolman type IV fluid in terms of quadratures. It is also shown that the rotating version of the Tolman IV space-time cannot be Petrov type D.