Effects of Spin-Isospin Modes in Transport Simulations

In-medium properties derived for nuclear matter in a microscopic pi + nucleon-hole + delta-hole model are incorporated into transport simulations of nuclear collisions by means of a local-density approximation and by utilizing a local medium frame. Certain features of the transport results differ from those based on the corresponding vacuum properties. Comparisons of the pi and delta production rates, as well as pion energy spectra, are discussed in particular.Comment: 11 pages total, Latex with psfig, and embedded 4 eps figure

Spin-Isospin Modes in Heavy-Ion Collisions I: Nuclear Matter at Finite Temperatures

With a view towards implementation in microscopic transport simulations of heavy-ion collisions, the properties of spin-isospin modes are studied in nuclear matter consisting of nucleons and Delta isobars that interact by the exchange of pi and rho mesons. For a standard p-wave interaction and an effective g' short-range interaction, the dispersion relations for the spin- isospin modes, and the associated amplitudes, are calculated at various nuclear densities and temperatures, within the random-phase approximation. Quantities of physical interest are then extracted, including the total and partial Delta decay widths and the Delta cross sections in the nuclear medium. The self-consistent inclusion of the Delta width has a strong effect on the Delta cross sections at twice normal nuclear density, as compared with the result of ignoring the width. Generally, the obtained quantities exhibit a strong density dependence, but are fairly insensitive to the temperature, at least up to T=25 MeV. Finally, it is described how these in-medium effects may be consistently included into microscopic transport simulations of nuclear collisions, and the improvements over previous approaches are discussed.Comment: LaTeX 47 pages, 17 postscript figures in accompanying uuencoded fil

Exit, Voice, and Disloyalty

Innomhuspositioneringssystem kan med fördel användas i många olika tillämpningar, allt från sjukhus till shoppingcenter. Denna rapport behandlar olika tekniker och lösningar för att designa ett positioneringssystem. Rapporten tar även upp i detalj hur ett system kan konstrueras av ZigBee kombinerat med dödräkning

Implications of two-body fragment decay for the interpretation of emission chronology from velocity-gated correlation functions

From velocity-gated small-angle correlation functions the emission chronology can be deduced for non-identical particles, if the emission is independent. This is not the case for non-identical particles that originate from two-body decay of fragments. Experimental results may contain contributions from both independent emission and two-body decay, so care is needed in interpreting the velocity-gated correlation functions. It is shown that in some special cases, it is still possible to deduce the emission chronology, even if there is a contribution from two-body decay.Comment: 15 pages, 4 figure

Treatment of Pionic Modes at the Nuclear Surface for Transport Descriptions

Dispersion relations and amplitudes of collective pionic modes are derived in a pi + nucleon-hole + delta-hole model for use in transport descriptions by means of a local density approximation. It is discussed how pionic modes can be converted to real particles when penetrating the nuclear surface and how earlier treatments can be improved. When the surface is stationary only free pions emerge. The time-dependent situation is also addressed, as is the conversion of non-physical (i.e. unperturbed delta-hole) modes to real particles when the nuclear density vanishes. A simplified one-dimensional scenario is used to investigate the reflection and transmission of pionic modes at the nuclear surface. It is found that reflection of pionic modes is rather unlikely, but the process can be incorporated into transport descriptions by the use of approximate local transmission coefficients.Comment: LaTeX 24 pages, 12 postscript figures in accompanying uuencoded fil

Are enrollment sites the key to optimizing participation in genetic studies?

In a time when the challenge of people being over-researched and experiencing research fatigue is increasingly discussed, low participation rates and potential sample biases are a growing concern in genetic research. In a recent study assessing factors relevant to successful recruitment of patients with myocardial infarction to a genetic study, enrollment site was identified as the most important factor associated with patient participation, whereas patient-level factors such as race, gender and education played a limited or no role. These results underline the importance of appropriate recruitment routines at enrollment sites in order to reach high levels of participation in genetic research