Eff ect of Revalor- XH, Revalor- 200, and Combination Revalor- IH/Revalor- 200 on Yearling Heifer Growth Performance and Carcass Characteristics

A commercial feedlot trial tested three implant strategies (Revalor- 200 on day 0, Revalor- IH on d 0 and re- implanted with Revalor- 200 on d 56, or Revalor- XH on d 0) on growth performance and carcass characteristics of heifers fed for 138 d. Th ere were no differences observed for final body weight, dry matter intake, or average daily gain on a live basis among implant strategies. Heifers implanted with Revalor- IH/200 combination had greater carcass- adjusted final body weight and improved feed conversion compared to Revalor- 200 and Revalor- XH. Hot carcass weights, dressing percent, and LM area were improved for Revalor- IH/200 implanted heifers relative to Revalor- 200 and Revalor- XH implanted heifers. Marbling score and 12th- rib fat thickness were not different among implant treatments. Heifers implanted with Revalor- IH/200 had a shift to a lower USDA yield grade distribution compared to 200 and XH implanted heifers. Th e greater concentration of trenbolone acetate and estradiol provided by Revalor- IH/200 combination slightly improved growth and carcass performance compared to the non- coated Revalor- 200 implant and partially coated Revalor- XH implant

Eff ect of Revalor- XH, Revalor- 200, and Combination Revalor- IH/Revalor- 200 on Yearling Heifer Growth Performance and Carcass Characteristics

A commercial feedlot trial tested three implant strategies (Revalor- 200 on day 0, Revalor- IH on d 0 and re- implanted with Revalor- 200 on d 56, or Revalor- XH on d 0) on growth performance and carcass characteristics of heifers fed for 138 d. Th ere were no differences observed for final body weight, dry matter intake, or average daily gain on a live basis among implant strategies. Heifers implanted with Revalor- IH/200 combination had greater carcass- adjusted final body weight and improved feed conversion compared to Revalor- 200 and Revalor- XH. Hot carcass weights, dressing percent, and LM area were improved for Revalor- IH/200 implanted heifers relative to Revalor- 200 and Revalor- XH implanted heifers. Marbling score and 12th- rib fat thickness were not different among implant treatments. Heifers implanted with Revalor- IH/200 had a shift to a lower USDA yield grade distribution compared to 200 and XH implanted heifers. Th e greater concentration of trenbolone acetate and estradiol provided by Revalor- IH/200 combination slightly improved growth and carcass performance compared to the non- coated Revalor- 200 implant and partially coated Revalor- XH implant

A SCUBA-2 850-μm survey of protoplanetary discs in the σ Orionis cluster

We present the results from a large 850-μm survey of the σ Orionis cluster using the SCUBA-2 camera on the James Clerk Maxwell Telescope. The 0 ∘.5 diameter circular region we surveyed contains 297 young stellar objects with an age estimated at about 3 Myr. We detect nine of these objects, eight of which have infrared excesses from an inner disc. We also serendipitously detect three non-stellar sources at >5σ that are likely background submillimetre galaxies. The nine detected stars have inferred disc masses ranging from 5 to about 17 MJup, assuming similar dust properties as Taurus discs and an interstellar medium gas-to-dust ratio of 100. There is a net positive signal towards the positions of the individually undetected infrared excess sources indicating a mean disc mass of 0.5 MJup. Stacking the emission towards those stars without infrared excesses constrains their mean disc mass to less than 0.3 MJup, or an equivalent Earth mass in dust. The submillimetre luminosity distribution is significantly different from that in the younger Taurus region, indicating disc mass evolution as star-forming regions age and the infrared excess fraction decreases. Submillimetre Array observations reveal CO emission towards four sources demonstrating that some, but probably not much, molecular gas remains in these relatively evolved discs. These observations provide new constraints on the dust and gas mass of protoplanetary discs during the giant planet building phase and provide a reference level for future studies of disc evolution

\u3ci\u3eDrosophila\u3c/i\u3e Muller F Elements Maintain a Distinct Set of Genomic Properties Over 40 Million Years of Evolution

The Muller F element (4.2 Mb, ~80 protein-coding genes) is an unusual autosome of Drosophila melanogaster; it is mostly heterochromatic with a low recombination rate. To investigate how these properties impact the evolution of repeats and genes, we manually improved the sequence and annotated the genes on the D. erecta, D. mojavensis, and D. grimshawi F elements and euchromatic domains from the Muller D element. We find that F elements have greater transposon density (25–50%) than euchromatic reference regions (3–11%). Among the F elements, D. grimshawi has the lowest transposon density (particularly DINE-1: 2% vs. 11–27%). F element genes have larger coding spans, more coding exons, larger introns, and lower codon bias. Comparison of the Effective Number of Codons with the Codon Adaptation Index shows that, in contrast to the other species, codon bias in D. grimshawi F element genes can be attributed primarily to selection instead of mutational biases, suggesting that density and types of transposons affect the degree of local heterochromatin formation. F element genes have lower estimated DNA melting temperatures than D element genes, potentially facilitating transcription through heterochromatin. Most F element genes (~90%) have remained on that element, but the F element has smaller syntenic blocks than genome averages (3.4–3.6 vs. 8.4–8.8 genes per block), indicating greater rates of inversion despite lower rates of recombination. Overall, the F element has maintained characteristics that are distinct from other autosomes in the Drosophila lineage, illuminating the constraints imposed by a heterochromatic milieu