Decay rates of Neutral Mesons

The partial width for the observed decay mode ω→π^++π^-+π^0 can be estimated by assuming, in the sense of dispersion theory, that the process is dominated by ω→p+π followed by p→2π. We treat p as a nearly stable particle and define a coupling parameter f_(ωpπ)

Lidar Scanning of Momentum Flux in the Marine Boundary Layer

Momentum flux measurements are important for describing the wind profile in the atmospheric boundary layer, modeling the atmospheric flow over water, the accounting of exchange processes between air and sea, etc. It is also directly related to the friction velocity, which is a velocity scale required for wind engineering. Estimations of friction velocity over the sea can be performed by combining wind speed measurements, a sea roughness length formulation and the surface-layer wind profile, i.e. a bulk-derived method. This method was tested in Peña et al. (2008) by comparison with direct turbulence measurements from a sonic anemometer, showing high agreement. In this study, a conical scanning lidar is used to derive the momentum flux, which compares well to the estimations from the bulk-derived method, but it also shows a filtering effect due to the large spatial-averaging volume of the lidar. The spectral model by Mann (1994) is then used to numerically estimate the filtering effect of the lidar and the predictions have a good agreement with the observations for near-neutral conditions over the North Sea at the Horns Rev wind farm

A new population of recently quenched elliptical galaxies in the SDSS

We use the Sloan Digital Sky Survey to investigate the properties of massive elliptical galaxies in the local Universe (z\leq0.08) that have unusually blue optical colors. Through careful inspection, we distinguish elliptical from non-elliptical morphologies among a large sample of similarly blue galaxies with high central light concentrations (c_r\geq2.6). These blue ellipticals comprise 3.7 per cent of all c_r\geq2.6 galaxies with stellar masses between 10^10 and 10^11 h^{-2} {\rm M}_{\sun}. Using published fiber spectra diagnostics, we identify a unique subset of 172 non-star-forming ellipticals with distinctly blue urz colors and young (< 3 Gyr) light-weighted stellar ages. These recently quenched ellipticals (RQEs) have a number density of 2.7-4.7\times 10^{-5}\,h^3\,{\rm Mpc}^{-3} and sufficient numbers above 2.5\times10^{10} h^{-2} {\rm M}_{\sun} to account for more than half of the expected quiescent growth at late cosmic time assuming this phase lasts 0.5 Gyr. RQEs have properties that are consistent with a recent merger origin (i.e., they are strong `first-generation' elliptical candidates), yet few involved a starburst strong enough to produce an E+A signature. The preferred environment of RQEs (90 per cent reside at the centers of < 3\times 10^{12}\,h^{-1}{\rm M}_{\sun} groups) agrees well with the `small group scale' predicted for maximally efficient spiral merging onto their halo center and rules out satellite-specific quenching processes. The high incidence of Seyfert and LINER activity in RQEs and their plausible descendents may heat the atmospheres of small host halos sufficiently to maintain quenching.Comment: 26 pages, 9 figures. Revised version; accepted for publication in MNRA

Mol. Cell. Proteomics

Post-translational modification of proteins by ubiquitin is a fundamentally important regulatory mechanism. However, proteome-wide analysis of endogenous ubiquitylation remains a challenging task, and almost always has relied on cells expressing affinity tagged ubiquitin. Here we combine single-step immunoenrichment of ubiquitylated peptides with peptide fractionation and high-resolution mass spectrometry to investigate endogenous ubiquitylation sites. We precisely map 11,054 endogenous putative ubiquitylation sites (diglycine-modified lysines) on 4,273 human proteins. The presented data set covers 67% of the known ubiquitylation sites and contains 10,254 novel sites on proteins with diverse cellular functions including cell signaling, receptor endocytosis, DNA replication, DNA damage repair, and cell cycle progression. Our method enables site-specific quantification of ubiquitylation in response to cellular perturbations and is applicable to any cell type or tissue. Global quantification of ubiquitylation in cells treated with the proteasome inhibitor MG-132 discovers sites that are involved in proteasomal degradation, and suggests a nonproteasomal function for almost half of all sites. Surprisingly, ubiquitylation of about 15% of sites decreased more than twofold within four hours of MG-132 treatment, showing that inhibition of proteasomal function can dramatically reduce ubiquitylation on many sites with non-proteasomal functions. Comparison of ubiquitylation sites with acetylation sites reveals an extensive overlap between the lysine residues targeted by these two modifications. However, the crosstalk between these two post-translational modifications is significantly less frequent on sites that show increased ubiquitylation upon proteasome inhibition. Taken together, we report the largest site-specific ubiquitylation dataset in human cells, and for the first time demonstrate proteome-wide, site-specific quantification of endogenous putative ubiquitylation sites

Pyrosequencing reveals diverse fecal microbiota in Simmental calves during early development

From birth to the time after weaning the gastrointestinal microbiota of calves must develop into a stable, autochthonous community accompanied by pivotal changes of anatomy and physiology of the gastrointestinal tract. The aim of this pilot study was to examine the fecal microbiota of six Simmental dairy calves to investigate time-dependent dynamics of the microbial community. Calves were followed up from birth until after weaning according to characteristic timepoints during physiological development of the gastrointestinal tract. Pyrosequencing of 16S rRNA gene amplicons from 35 samples yielded 253,528 reads clustering into 5410 operational taxonomic units based on 0.03 16S rRNA distance. Operational taxonomic units were assigned to 296 genera and 17 phyla with Bacteroidetes, Firmicutes, and Proteobacteria being most abundant. An age-dependent increasing diversity and species richness was observed. Highest similarities between fecal microbial communities were found around weaning compared with timepoints from birth to the middle of the milk feeding period. Principal coordinate analysis revealed a high variance particularly in samples taken at the middle of the milk feeding period (at the age of approximately 40 days) compared to earlier timepoints, confirming a unique individual development of the fecal microbiota of each calf. This study provides first deep insights into the composition of the fecal microbiota of Simmental dairy calves and might be a basis for future more detailed studies