25,050 research outputs found
Nuclear Chronometers
Observations of metal-poor Galactic halo stars indicate that the abundance
pattern of the (heaviest) neutron-capture elements is consistent with the
scaled solar system r-process abundances. Utilizing the radioactive (r-process)
element thorium, age determinations have been made for several of these same
stars, placing constraints on both Galactic and cosmological age estimates.Comment: 6 pages, 2 figures. To appear in the Proceedings of ``Cosmic
Evolution'
Neutron-Capture Element Trends in the Halo
In a brief review of abundances neutron-capture elements (Z > ~30) in
metal-poor halo stars, attention is called to their star-to-star scatter, the
dominance of r-process synthesis at lowest metallicities, the puzzle of the
lighter members of this element group, and the possibility of a better
r-/s-process discriminant.Comment: 6 pages, 2 figures. To appear in the Proceedings of ``Cosmic
Evolution'
Bulk sediment parameters (CaCO3, TOC, >63µm) of Sites 1095, 1096, 1101 and coarse fraction analysis of Site 1095 (ODP Leg 178, Western Antarctic Peninsula)
Effects of motion on jet exhaust noise from aircraft
The various problems involved in the evaluation of the jet noise field prevailing between an observer on the ground and an aircraft in flight in a typical takeoff or landing approach pattern were studied. Areas examined include: (1) literature survey and preliminary investigation, (2) propagation effects, (3) source alteration effects, and (4) investigation of verification techniques. Sixteen problem areas were identified and studied. Six follow-up programs were recommended for further work. The results and the proposed follow-on programs provide a practical general technique for predicting flyover jet noise for conventional jet nozzles
Wealth Effects of Banks' Rights to Market and Originate Annuities
We examine wealth effects, for banks and insurers, of bank rights to sell and underwrite annuities. The stock-price reactions to four court and regulatory decisions are consistent with expectations of bank gains at insurers' expense. Cross-sectionally, smaller, riskier insurers with higher distribution costs and substantial annuity business sustain larger wealth losses. Larger, riskier bank holding companies with fee- based and consumer business gain most, consistent with the extension of federal safety-net guarantees as a source of gains. Banking stock-price reactions to the Supreme Court's decision are opposite other findings, possibly reflecting unfulfilled expectations of a broader mandate for expanded bank rights.Annuities, VALIC, financial modernization, deregulation, deposit insurance, Blackfeet National Bank, event studies
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