K+ and K- production in heavy-ion collisions at SIS-energies

The production and the propagation of K+ and of K- mesons in heavy-ion collisions at beam energies of 1 to 2 AGeV have systematically been investigated with the Kaon Spectrometer KaoS at the SIS at the GSI. The ratio of the K+ production excitation function for Au+Au and for C+C reactions increases with decreasing beam energy, which is expected for a soft nuclear equation-of-state. At 1.5 AGeV a comprehensive study of the K+ and of the K- emission as a function of the size of the collision system, of the collision centrality, of the kaon energy, and of the polar emission angle has been performed. The K-/K+ ratio is found to be nearly constant as a function of the collision centrality. The spectral slopes and the polar emission patterns are different for K- and for K+. These observations indicate that K+ mesons decouple earlier from the reaction zone than K- mesons.Comment: invited talk given at the SQM2003 conference in Atlantic Beach, USA (March 2003), to be published in Journal of Physics G, 10pages, 7 figure

Evidence for Different Freeze-Out Radii of High- and Low-Energy Pions Emitted in Au+Au Collisions at 1 GeV/nucleon

Double differential production cross sections of negative and positive pions and the number of participating protons have been measured in central Au+Au collisions at 1 GeV per nucleon incident energy. At low pion energies the pi^- yield is strongly enhanced over the pi^+ yield. The energy dependence of the pi^-/pi^+ ratio is assigned to the Coulomb interaction of the charged pions with the protons in the reaction zone. The deduced Coulomb potential increases with increasing pion c.m. energy. This behavior indicates different freeze-out radii for different pion energies in the c.m.~frame.Comment: IKDA is the Institute for Nuclear Physics in Darmstadt/German

Evaluation of sterol and triacylglicerol composition during ripening process of the hazelnuts (Corylus avellana L.) grown in Poland

The composition of the hazelnuts\u2019 lipid fraction changes during maturation. This includes the sterols content and occurrence of different types of triacylglycerol (TAG) molecules. From the nutritional point of view, TAGs and sterols content are extremely important. Both, the dietary and technological features of hazelnut oil depend mainly on TAG composition and principal endogenous antioxidants present in nuts. The principal aim of this research was to investigate both, the quantitative and qualitative changes of TAGs and sterols occurring during ripening of Polish hazelnuts. Investigated hazelnuts (var. Webba Cenny, Syrena) were cultivated in experimental orchard in the south of Poland and had been collected for 5 consecutive weeks (August-September). Preliminary vacuum packed nuts were stored in -18\ub0C until they were analysed. Due to free + esterified phytosterols determination, approximately 0.5 mL of dihydrocholesterol (c = 2.0 mg/mL) was added to 250 mg of fat and further analysis was conducted according to Ciemniewska-\u17bytkiewicz et al. (2015). TAG analysis was conducted by GC-FID with the injection of 1 \uf06dL of organic solution (3 mg/mL of sample in hexane). The separation was perfomed with a fused silica capillary column (30 m, 0.25 mm i.d., 0.10 mm film thickness.) with 35% dimethyl, 65% diphenyl polysiloxane and a split ratio set at 1:30. The initial oven temperature of 345\ub0C was raised to 352\ub0C at a rate of 0.5 \ub0C min-1 and kept for 3 min. The injector and detector temperatures were set at 360 \ub0C. Hydrogen was used as a carrier gas at a flow rate of 1.75 mL min -1. The Identification was carried out by comparison with a mixture of standards and quantification was achieved by use of an internal standard (tricaprylin, 0.25 mg mL-1). The methodology for the analysis was based on the separation of classes of hazelnut fat TGs according to the total number of carbon atom