Prinosi čestica, skaliranje antiprotona i prosječni poprečni impulsi u sudarima olovo–olovo na visokoj energiji: modelska studija

The study aims at explaining the behaviour of some of the very important observables measured in the latest lead-lead collisions at CERN in the light of a variety of the sequential chain model. Calculated values, to our surprise, are in excellent agreement with the measurements, especially when the effect of cascading and rescattering is empirically introduced in the calculations of the average transverse momenta. Implications of the results are discussed.Pokušavamo objasniti svojstva nekih vrlo važnih opservabli koje su u CERNu mjerili u najnovijim sudarima olovo–olovo i to na osnovi inačice modela lančastih nizova. Na naše iznenađenje, izračunate su vrijednosti u izvrsnom skladu s ishodima mjerenja, posebice kada se kaskade i višestruko raspršenje iskustveno uvedu u račun poprečnih impulsa. Raspravljaju se posljedice usporedbi

Transverse Momentum Spectra of Pions in Particle and Nuclear Collisions and Some Ratio-Behaviours: Towards A Combinational Approach

The nature of transverse momentum dependence of the inclusive cross-sections for secondary pions produced in high energy hadronic($PP$), hadronuclear($PA$) and nuclear($AA$) collisions has here been exhaustively investigated for a varied range of interactions in a unified way with the help of a master formula. This formula evolved from a new combination of the basic Hagedorn's model for particle(pion) production in PP scattering at ISR range of energies, a phenomenological approach proposed by Peitzmann for converting the results of $NN(PP)$ reactions to those for either $PA$ or $AA$ collisions, and a specific form of parametrization for mass number-dependence of the nuclear cross sections. This grand combination of models(GCM) is then applied to analyse the assorted extensive data on various high energy collisions. The nature of qualitative agreement between measurements and calculations on both the inclusive cross-sections for production of pions, and some ratios of them as well, is quite satisfactory. The modest successes that we achieve here in dealing with the massive data-sets are somewhat encouraging in view of the diversity of the reactions and the very wide range of interaction energies.Comment: 19 pages, 19 figure

An N-Terminal Threonine Mutation Produces an Efflux-Favorable, Sodium-Primed Conformation of the Human Dopamine Transporter

ABSTRACT The dopamine transporter (DAT) reversibly transports dopamine (DA) through a series of conformational transitions. Alanine (T62A) or aspartate (T62D) mutagenesis of Thr62 revealed T62D-human (h)DAT partitions in a predominately efflux-preferring conformation. Compared with wild-type (WT), T62D-hDAT exhibits reduced [ 3 H]DA uptake and enhanced baseline DA efflux, whereas T62A-hDAT and WT-hDAT function in an influxpreferring conformation. We now interrogate the basis of the mutants' altered function with respect to membrane conductance and Na 1 sensitivity. The hDAT constructs were expressed in Xenopus oocytes to investigate if heightened membrane potential would explain the efflux characteristics of T62D-hDAT. In the absence of substrate, all constructs displayed identical resting membrane potentials. Substrate-induced inward currents were present in oocytes expressing WT-and T62A-hDAT but not T62D-hDAT, suggesting equal bidirectional ion flow through T62D-hDAT. Utilization of the fluorescent DAT substrate or by application of amphetamine. We conclude that T62D-hDAT represents an efflux-willing, Na 1 -primed orientationpossibly representing an experimental model of the conformational impact of amphetamine exposure to hDAT