نتایج جستجو برای: abundances

تعداد نتایج: 16306  

2009
Wako Aoki Paul S. Barklem Timothy C. Beers John E. Norris Daniela Carollo

We have determined Li abundances for eleven metal-poor turn-off stars, among which eight have [Fe/H] < −3, based on LTE analyses of high-resolution spectra obtained with the HDS on the Subaru telescope. The Li abundances for four of these eight stars are determined for the first time by this study. Effective temperatures are determined by a profile analysis of Hα and Hβ. While seven stars have ...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2006
A Dalgarno

The chemistry that occurs in the interstellar medium in response to cosmic ray ionization is summarized, and a review of the ionization rates that have been derived from measurements of molecular abundances is presented. The successful detection of large abundances of H(3)(+) in diffuse clouds and the recognition that dissociative recombination of H(3)(+) is fast has led to an upward revision o...

2002
Christopher Sneden John J. Cowan James E. Lawler Scott Burles

Europium isotopic abundance fractions are reported for the very metal-poor, neutron-capture-rich giant stars CS 22892-052, HD 115444, and BD +17◦3248. The abundance fractions, derived from analysis of several strong Eu II lines appearing in high-resolution spectra of these stars, are in excellent agreement with each other and with their values in the Solar System: fr(Eu)≃ fr(Eu) ≃ 0.5. Detailed...

2000
G. ISRAELIAN R. J. GARCIA LOPEZ R. REBOLO

We present results on carbon, nitrogen, and oxygen abundances for a sample of unevolved metal-poor stars with metallicities in the range −0.3< [Fe/H]< −3. Oxygen abundances derived from different indicators are compared showing consistently that in the range 0.3 >[Fe/H]> −3.0, the [O/Fe] ratio increases from approximately 0 to 1. We find a good agreement between abundances based on the forbidde...

2008
Guillermo Gonzalez

We compare the Li abundances of a sample of stars with planets discovered with the Doppler method to a sample of stars without detected planets. We prepared the samples by combining the Li abundances reported in several recent studies in a consistent way. Our results confirm recent claims that the Li abundances of stars with planets are smaller than those of stars without planets near the solar...

2008
Brian E. Wood Seth Redfield Jeffrey L. Linsky

We use ultraviolet spectra of Capella from the Hubble Space Telescope (HST) and Far Ultraviolet Spectroscopic Explorer (FUSE) satellites to study interstellar absorption lines from the Local Interstellar Cloud (LIC). Measurements of these lines are used to empirically determine the ionization states of carbon, nitrogen, and silicon in the LIC, for comparison with the predictions of theoretical ...

2017
Fanqiang Kong Chending Bian

Abstract—In this work, we exploit two assumed properties of the abundances of the observed signatures (endmembers) in order to reconstruct the abundances from hyperspectral data. Joint-sparsity is the first property of the abundances, which assumes the adjacent pixels can be expressed as different linear combinations of same materials. The second property is rank-deficiency where the number of ...

Journal: Geopersia 2015

The investigated section cropping out in Kuh-e-Banesh, Zagros basin (southern Iran) is represented by limestone, Cherty beds and marllevels bearing abundant Planktonic foraminifers, radiolarian microfaunas, and ammonite imprints. For the first time, well to moderatelypreserved forms of Planktonic foraminifera have been extracted from black shale and marls levels. Extracted biota was studied wit...

RNA-sequencing is a new method of transcriptome characterization of organisms. Based on identity and relatedness, there are large genetic variations among different cattle breeds. The goal of the current study was to sequence the transcriptome of Guilan native cow and compare with available reference genome using RNA-sequencing method. Blood samples were collected from 14 Guilan native cows and...

Fatemi , M.R., Jamili, Sh., Mokhayer , Z., Mousavi Nadushan , R., Rabbaniha, M., Safavi, S.E.,

Coastal ecosystems of Bushehr are shallow environments subject to human impacts, including shrimp aquaculture and urban expansion activities. A spatial-temporal study was conducted in order to assess the actual ecological status of the creeks, estuary and marine sites on the basis of their taxonomic composition and density of mesozooplankton. Zooplankton species distribution and abundance data ...

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