The production of pions and kaons has been measured in 197Au+197Au collisions at beam energies from 0.6 to 1.5A GeV with the kaon spectrometer at SIS/GSI. The K+ meson multiplicity per nucleon is ...enhanced in Au+Au collisions by factors up to 6 relative to C+C reactions, whereas the corresponding pion ratio is reduced. The ratio of the K+ meson excitation functions for Au+Au and C+C collisions increases with decreasing beam energy. This behavior is expected for a soft nuclear equation-of-state.
In relativistic heavy ion collisions, heavy flavor is expected to result predominately from initial hard parton–parton scatterings. Hence, in the absence of later stage effects, the production of ...heavy flavor in A+A collisions can be viewed as a superposition of N+N collisions. Measurements of v2 or RAA of heavy flavor (or their decay electrons) in A+A collisions violate the simple superposition picture and therefore present themselves as probes of the medium formed in such collisions. On the basis of the measured v2 and RAA of non-photonic single electrons in A+A collisions at RHIC, we will investigate the interplay between these observables as well as the restrictions they pose for charm and bottom production.
Differential production cross sections of K+/- mesons have been measured in p + C and p + Au collisions at 1.6, 2.5, and 3.5 GeV proton beam energy. At beam energies close to the production ...threshold, the K- multiplicity is strongly enhanced with respect to proton-proton collisions. According to microscopic transport calculations, this enhancement is caused by two effects: the strangeness exchange reaction NY --> K- NN and an attractive in-medium K- N potential at saturation density.
Rice's (9144, 1945) sum of sinusoids can be used for an efficient approximation of colored Gaussian noise processes and is therefore of great importance to the software and hardware realization of ...mobile fading channel models. Although several methods can be found in the literature for the computation of the parameters characterizing a proper set of sinusoids, less is reported about the statistical properties of the resulting (deterministic) simulation model. In this paper, not only is the simulation model's amplitude and phase probability density function (PDF) investigated, but also higher order statistics e.g., level-crossing rate (LCR) and average duration of fades (ADFs). It is shown that due to the deterministic nature of the simulation model, analytical expressions for the PDF of the amplitude and phase, autocorrelation function (ACF), crosscorrelation function (CCF), LCR, and ADFs can be derived. We also propose a new procedure for the determination of an optimal set of sinusoids, i.e., the method results for a given number of sinusoids in an optimal approximation of Gaussian, Rayleigh, and Rice processes with given Doppler power spectral density (PSD) properties. It is shown that the new method can easily be applied to the approximation of various other kinds of distribution functions, such as the Nakagami (1960) and Weibull distributions. Moreover, a quasi-optimal parameter computation method is presented.
Joint dislocations are always accompanied by rupture of the joint capsule. Depending on the forces exerted on the joint as well as individual bone quality, fractures (dislocation fractures) and ...injuries to ligaments occur. As blood vessels and nerves can also be damaged, reduction is an urgent measure. Only impaired peripheral perfusion, loss of motor function or sensation justify reduction without radiological documentation. As reduction can be a painful procedure, analgosedation is nearly always necessary. Evidence for superiority of individual maneuvers is weak. Reduction is followed by immobilization and documented by another control X‑ray. Follow-up treatment depends on concomitant injuries, age and individual demands on joint function. Even with correct follow-up treatment, deficits often persist. This article deals with the diagnostics and treatment of dislocations of the shoulder, elbow, hip, patella and knee.
Differential production cross sections of K- and K+ mesons have been measured in Ni+Ni and Au+Au collisions at a beam energy of 1.5 A GeV. The K(-)/K(+) ratio is found to be nearly constant as a ...function of the collision centrality and system size. The spectral slopes and the polar emission pattern differ for K- and K+ mesons. These observations indicate that K+ mesons decouple earlier from the fireball than K- mesons.
We present a novel computer simulation model for a land mobile radio channel. The underlying channel model takes for granted non-frequency-selective fading but considers the effects caused by ...shadowing. For such a channel model we design a simulation model that is based on an efficient approximation of filtered white Gaussian noise processes by finite sums of properly weighted sinusoids with uniformly distributed phases. In all, four completely different methods for the computation of the coefficients of the simulation model are introduced. Furthermore, the performance of each procedure is investigated on the basis of two quality criteria. All the presented methods have in common the fact that the resulting simulation model has a completely determined fading behavior for all time. Therefore, the simulation model can be interpreted as a deterministic model that approximates stochastic processes such as Rayleigh, log-normal, and Suzuki (1977) processes.
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