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We present the measurements of the small-scale clustering for the emission-line galaxy (ELG) sample from the extended Baryon Oscillation Spectroscopic Survey (eBOSS) in the Sloan Digital Sky Survey IV (SDSS-IV). We use conditional abundance matching method to interpret the clustering measurements from 0.34 to $70\, h^{-1}\, \textrm {Mpc}$. In order to account for the correlation between properties of ELGs and their environment, we add a secondary connection between star formation rate of ELGs and halo accretion rate. Three parameters are introduced to model the ELG [O ii] luminosity and to mimic the target selection of eBOSS ELGs. The parameters in our models are optimized using Markov Chain Monte Carlo (MCMC) method. We find that by conditionally matching star formation rate of galaxies and the halo accretion rate, we are able to reproduce the eBOSS ELG small-scale clustering within 1σ error level. Our best-fitting model shows that the eBOSS ELG sample only consists of $\sim 12{{\ \rm per\ cent}}$ of all star-forming galaxies, and the satellite fraction of eBOSS ELG sample is 19.3 per cent. We show that the effect of assembly bias is $\sim 20{{\ \rm per\ cent}}$ on the two-point correlation function and $\sim 5{{\ \rm per\ cent}}$ on the void probability function at scale of $r\sim 20 \, h^{-1}\, \rm Mpc$.

 

Paramecium bursaria chlorella virus-1 (PBCV-1) is a large double-stranded DNA (dsDNA) virus that infects the unicellular green alga Chlorella variabilis NC64A. Unlike many other viruses, PBCV-1 encodes most, if not all, of the enzymes involved in the synthesis of the glycans attached to its major capsid protein. Importantly, these glycans differ from those reported from the three domains of life in terms of structure and asparagine location in the sequon of the protein. Previous data collected from 20 PBCV-1 spontaneous mutants (or antigenic variants) suggested that the a064r gene encodes a glycosyltransferase (GT) with three domains, each with a different function. Here, we demonstrate that: domain 1 is a β- l -rhamnosyltransferase; domain 2 is an α- l -rhamnosyltransferase resembling only bacterial proteins of unknown function, and domain 3 is a methyltransferase that methylates the C-2 hydroxyl group of the terminal α- l -rhamnose (Rha) unit. We also establish that methylation of the C-3 hydroxyl group of the terminal α- l -Rha is achieved by another virus-encoded protein A061L, which requires an O-2 methylated substrate. This study, thus, identifies two of the glycosyltransferase activities involved in the synthesis of the N -glycan of the viral major capsid protein in PBCV-1 and establishes that a single protein A064R possesses the three activities needed to synthetize the 2-OMe-α- l -Rha-(1→2)-β- l -Rha fragment. Remarkably, this fragment can be attached to any xylose unit. 

Abstract This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete release of the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal of surveying over 10,000 nearby galaxies. The complete release of the MaNGA Stellar Library accompanies this data, providing observations of almost 30,000 stars through the MaNGA instrument during bright time. DR17 also contains the complete release of the Apache Point Observatory Galactic Evolution Experiment 2 survey that publicly releases infrared spectra of over 650,000 stars. The main sample from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), as well as the subsurvey Time Domain Spectroscopic Survey data were fully released in DR16. New single-fiber optical spectroscopy released in DR17 is from the SPectroscipic IDentification of ERosita Survey subsurvey and the eBOSS-RM program. Along with the primary data sets, DR17 includes 25 new or updated value-added catalogs. This paper concludes the release of SDSS-IV survey data. SDSS continues into its fifth phase with observations already underway for the Milky Way Mapper, Local Volume Mapper, and Black Hole Mapper surveys.