1,035 research outputs found

    Relation between the phenomenological interactions of the algebraic cluster model and the effective two--nucleon forces

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    We determine the phenomenological cluster--cluster interactions of the algebraic model corresponding to the most often used effective two--nucleon forces for the 16^{16}O + α\alpha 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

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    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, Z=0.0028Z= 0.0028, [Fe/H] 0.7\approx -0.7). New evolutionary sequences and post-processing nucleosynthesis results are presented for initial masses between 1MM_{\odot} and 7MM_{\odot}, where the 7MM_{\odot} is a super-AGB star with an O-Ne core. Models above 1.15MM_{\odot} become carbon rich during the AGB, and hot bottom burning begins in models M3.75MM \ge 3.75 M_{\odot}. 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., 12^{12}C/13^{13}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--7MM_{\odot} and nucleosynthesis results for three masses (M=3.75,5,7MM=3.75, 5, 7M_{\odot}) including ss-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

    Perspectives of women and partners from migrant and refugee backgrounds accessing the Cross Cultural Worker Service in maternity and early childhood services—a survey study

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    Background: Women from migrant and refugee backgrounds living in high-income countries have increased risk of adverse perinatal outcomes and report lower satisfaction with perinatal healthcare. In Sydney, Australia, a new service known as the Cross Cultural Workers (CCWs) in Maternity and Child and Family Health Service (the CCW Service) was implemented to support such women and families from pregnancy to the early parenting period. This study aimed to ascertain the experiences of women and their partners engaging with the CCW Service. Methods: A survey study was undertaken. Women accessing the CCW Service were recruited during pregnancy and were asked to complete surveys at three time points: in the third trimester of pregnancy, at 6 and 12 months postpartum. Their partners were invited to complete a survey at 6 months postpartum. Survey data were analysed to compare satisfaction, usefulness, number of CCW interactions, cultural sensitivity, and service improvement recommendations across all three survey timepoints. Results: A total of 231 surveys were received: 113 during pregnancy, 50 at 6-months postpartum, 44 at 12-months postpartum, and 24 partner surveys. Participants in all surveys reported the CCW Service to be useful (84–94%), stating that it increased their understanding of pregnancy, birth and parenting (95–100%), and that they would recommend the CCW Service (92–98%). Participants experienced a high level of satisfaction (88–95%) irrespective of the number of CCW interactions (p = 0.42). Thoughts on becoming a mother or parent were more positive after meeting the CCW than before for both women (p = 0.01) and partners (p = 0.12). Suggestions for CCW Service improvement were to 1) increase the provision of information, specifically financial entitlements, postnatal depression, and support services, 2) increase involvement of partners in care, 3) increase the CCW workforce/or number of CCWs. Conclusion: The CCW Service was associated with positive experiences and high rates of satisfaction at all timepoints. This service has the potential to inform the implementation of similar models of care that improve accessibility, the perinatal experience, and respond to the unique needs of women and families from migrant and refugee backgrounds

    Matchings with lower quotas: Algorithms and complexity = Alsó kvótás párosítások: algoritmusok és komplexitás

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    New and simple algorithms for stable flow problems

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    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

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    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
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