469 research outputs found
Targeting of anionic membrane species by lanthanide(III) complexes: towards improved MRI contrast agents for apoptosis
No abstract available
Targeting of anionic membrane species by lanthanide(III) complexes: towards improved MRI contrast agents for apoptosis
No abstract available
Changes in r-process abundances at late times
We explore changes in abundance patterns that occur late in the r process. As
the neutrons available for capture begin to disappear, a quasiequilibrium
funnel shifts material into the large peaks at A=130 and A=195, and into the
rare-earth "bump" at A=160. A bit later, after the free-neutron abundance has
dropped and beta-decay has begun to compete seriously with neutron capture, the
peaks can widen. The degree of widening depends largely on neutron-capture
rates near closed neutron shells and relatively close to stability. We identify
particular nuclei the capture rates of which should be examined experimentally,
perhaps at a radioactive beam facility.Comment: 8 pages, 14 figures included in tex
The impact of nuclear masses near on -process abundances
We have performed for the first time a complete -process mass sensitivity
study in the region. We take into account how an uncertainty in a single
nuclear mass propagates to influence important quantities of neighboring
nuclei, including Q-values and reaction rates. We demonstrate that nuclear mass
uncertainties of MeV in the region result in up to an order of
magnitude local change in -process abundance predictions. We identify key
nuclei in the study whose mass has a substantial impact on final -process
abundances and could be measured at future radioactive beam facilities.Comment: 7 pages, 3 figures, submitte
The Influence Of Neutron Capture Rates On The Rare Earth Region Of The r-Process Abundance Pattern
We study the sensitivity of the r-process abundance pattern to neutron
capture rates along the rare earth region (A~150 to A~180). We introduce the
concepts of large nuclear flow and flow saturation which determine the neutron
capture rates that are influential in setting the rare earth abundances. We
illustrate the value of the two concepts by considering high entropy conditions
favorable for rare earth peak production and identifying important neutron
capture rates among the rare earth isotopes. We also show how these rates
influence nuclear flow and specific sections of the abundance pattern.Comment: 14 pages, 7 figures, submitted to PR
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