Despite the fact that tRNA abundances are thought to play a major role in determining translation error rates, their distribution across the genetic code and the resulting implications have received little attention. In general, studies of codon usage bias (CUB) assume that codons with higher tRNA abundance have lower missense error rates. Using a model of protein translation based on tRNA comp...

We report Sr, Pd and Ag abundances for a sample of metal-poor field giants and analyze a larger sample of Y, Zr, and Ba abundances. The [Y/Zr] and [Pd/Ag] abundance ratios are similar to those measured for the r-process-rich stars CS 22892-052 and CS 31082-001. The [Pd/Ag] ratio is larger than predicted from the solar-system r-process abundances. The constant [Y/Zr] and [Sr/Y] values in the fie...

We present results from an ongoing survey of the infrared emission lines [Kr III] 2.199 and [Se IV] 2.287 μm in Galactic planetary nebulae (PNe). Krypton and selenium may be produced by slow neutron-capture nucleosynthesis (the “s-process”) during the asymptotic giant branch (AGB) phase of PN progenitor stars, and brought to the surface by convective dredge-up before PN ejection. We detect emis...

The first observations of the infrared spectrum of the LMC planetary nebula SMP 83 as observed by the recently launched Spitzer Space Telescope are presented. The high-resolution (R 600) spectrum shows strong emission lines but no significant continuum. The infrared fine-structure lines are used, together with published optical spectra, to derive the electron temperature of the ionized gas for ...

Abundance observations indicate the presence of often surprisingly large amounts of neutron capture (i.e., sand r-process) elements in old Galactic halo and globular cluster stars. These observations provide insight into the nature of the earliest generations of stars in the Galaxy – the progenitors of the halo stars – responsible for neutron-capture synthesis. Comparisons of abundance trends c...

Dibutyl phthalate (DBP) is well known as a high-priority pollutant. This study explored the impacts of DBP on the metabolic pathways of microbes in black soils in the short term (20 days). The results showed that the microbial communities were changed in black soils with DBP. In nitrogen cycling, the abundances of the genes were elevated by DBP. DBP contamination facilitated 3'-phosphoadenosine...

Abundances of C, N, and O are determined in four bright red giants that span the known abundance range for light (Na and Al) and s-process (Zr and La) elements in the globular cluster NGC 1851. The abundance sum C+N+O exhibits a range of 0.6 dex, a factor of 4, in contrast to other clusters in which no significant C+N+O spread is found. Such an abundance range offers support for the Cassisi et ...

The natural abundance of 15N (expressed as delta 15N per mil relative to air N2) in the tissues and the change of 15N abundance during the digestion processess in cattle, pig, and goat were investigated. The 15N abundances of cattle tissues differed by about 3.5% with high values in heart, urinary bladder and diaphragm. The ages of cattle did not affect on the 15N abundances of liver and kidney...

MOTIVATION Metagenomics involves sampling and studying the genetic materials in microbial communities. Several statistical methods have been proposed for comparative analysis of microbial community compositions. Most of the methods are based on the estimated abundances of taxonomic units or functional groups from metagenomic samples. However, such estimated abundances might deviate from the tru...

We examine a hypothesized relationship between two descriptions of community structure: the niche-overlap dendrogram that describes the ecological similarities of species and the pattern of relative abundances. Specifically, we examine the way in which this relationship follows from the niche hierarchy model, whose fundamental assumption is a direct connection between abundances and underlying ...