1,030 research outputs found
Relation between the phenomenological interactions of the algebraic cluster model and the effective two--nucleon forces
We determine the phenomenological cluster--cluster interactions of the
algebraic model corresponding to the most often used effective two--nucleon
forces for the O + system.Comment: Latex with Revtex, 1 figure available on reques
Heavy-element yields and abundances of Asymptotic Giant Branch models with a Small Magellanic Cloud metallicity
We present new theoretical stellar yields and surface abundances for
asymptotic giant branch (AGB) models with a metallicity appropriate for stars
in the Small Magellanic Cloud (SMC, , [Fe/H] ). New
evolutionary sequences and post-processing nucleosynthesis results are
presented for initial masses between 1 and 7, where the
7 is a super-AGB star with an O-Ne core. Models above
1.15 become carbon rich during the AGB, and hot bottom burning
begins in models . We present stellar surface abundances
as a function of thermal pulse number for elements between C to Bi and for a
selection of isotopic ratios for elements up to Fe and Ni (e.g.,
C/C), which can be compared to observations. The integrated
stellar yields are presented for each model in the grid for hydrogen, helium
and all stable elements from C to Bi. We present evolutionary sequences of
intermediate-mass models between 4--7 and nucleosynthesis results
for three masses () including -process elements for
two widely used AGB mass-loss prescriptions. We discuss our new models in the
context of evolved AGB stars and post-AGB stars in the Small Magellanic Clouds,
barium stars in our Galaxy, the composition of Galactic globular clusters
including Mg isotopes with a similar metallicity to our models, and to
pre-solar grains which may have an origin in metal-poor AGB stars.Comment: 19 pages, accepted for publication in MNRA
Matchings with lower quotas: Algorithms and complexity = Alsó kvótás párosítások: algoritmusok és komplexitás
New and simple algorithms for stable flow problems
Stable flows generalize the well-known concept of stable matchings to markets
in which transactions may involve several agents, forwarding flow from one to
another. An instance of the problem consists of a capacitated directed network,
in which vertices express their preferences over their incident edges. A
network flow is stable if there is no group of vertices that all could benefit
from rerouting the flow along a walk.
Fleiner established that a stable flow always exists by reducing it to the
stable allocation problem. We present an augmenting-path algorithm for
computing a stable flow, the first algorithm that achieves polynomial running
time for this problem without using stable allocation as a black-box
subroutine. We further consider the problem of finding a stable flow such that
the flow value on every edge is within a given interval. For this problem, we
present an elegant graph transformation and based on this, we devise a simple
and fast algorithm, which also can be used to find a solution to the stable
marriage problem with forced and forbidden edges.
Finally, we study the stable multicommodity flow model introduced by
Kir\'{a}ly and Pap. The original model is highly involved and allows for
commodity-dependent preference lists at the vertices and commodity-specific
edge capacities. We present several graph-based reductions that show
equivalence to a significantly simpler model. We further show that it is
NP-complete to decide whether an integral solution exists
Discovery of the spectroscopic binary nature of the classical Cepheids FN Aql and V1344 Aql
We present the analysis of photometric and spectroscopic data of two
classical Cepheids, FN Aquilae and V1344 Aquilae. Based on the joint treatment
of the new and earlier radial velocity data, both Galactic Cepheids have been
found to be a member in a spectroscopic binary system.
To match the phases of the earlier radial velocity data correctly with the
new ones, we also determined the temporal behaviour of the pulsation period of
these Cepheids based on all available photometric data. The O-C graph covering
about half century shows slight changes in the pulsation period due to stellar
evolution for both Cepheids.Comment: 7 pages, 6 figures, 7 tables, accepted for publishing in the MNRA
Analysis of 3D filament structures in various magnetic configurations of the W7-X stellarator
Vitrification preserves chromatin integrity, bioenergy potential and oxidative parameters in mouse embryos
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