In chloroform solution, the syn/anti rotamer ratios for N-(2-pyridyl)carbamates, 3, and N-phenylcarbamates, 4, are close to 0.05. Addition of the double hydrogen bonding acetic acid moderately stabilizes the syn rotamer of 4, but has no measurable effect on the syn/anti ratio for 3. Conversely, the hydrogen bond donor-acceptor-donor triad in 2,6-bis(octylamido)pyridine, 1, strongly stabilizes the syn rotamer of 3, but has no effect on the syn/anti ratio for 4. The K(a) for syn-3:1 is 10(3)-10(4) times higher than the K(a) for anti-3:1. This implies that the alkoxy oxygen in anti-3 is a much poorer hydrogen bond acceptor than the carbonyl oxygen in syn-3, most likely because of a combination of steric and electrostatic factors.
We present our analysis of the Lyman continuum (LyC) emission and escape fraction of 111 spectroscopically verified galaxies with and without active galactic nuclei (AGN) from 2.26 < z < 4.3. We extended our ERS sample from Smith et al. with 64 galaxies in the GOODS North and South fields using WFC3/UVIS F225W, F275W, and F336W mosaics we independently drizzled using the HDUV, CANDELS, and UVUDF data. Among the 17 AGN from the 111 galaxies, one provided a LyC detection in F275W at
= 23.19 mag (signal-to-noise ratio, S/N, ≃ 133) and GALEX NUV at
= 23.77 mag (S/N ≃ 13). We simultaneously fit SDSS and Chandra spectra of this AGN to an accretion disk and Comptonization model, and find
values of
and
. For the remaining 110 galaxies, we stack image cutouts that capture their LyC emission using the F225W, F275W, and F336W data of the GOODS and ERS samples, and both combined, as well as subsamples of galaxies with and without AGN, and all galaxies. We find the stack of 17 AGN dominate the LyC production from
≃ 2.3–4.3 by a factor of ∼10 compared to all 94 galaxies without AGN. While the IGM of the early universe may have been reionized mostly by massive stars, there is evidence that a significant portion of the ionizing energy came from AGN.
Regenerative agriculture is both an attitude and a suite of practices that restores and maintains soil health and fertility, supports biodiversity, protects watersheds, and improves ecological and economic resilience. It focuses on creating the conditions for life above and below ground and takes its cues from nature, which has a very long track record of successfully growing things. By re-carbonizing soils via photosynthesis and biology, particularly on degraded land, regenerative agriculture can also sequester increasing quantities of atmospheric carbon (CO 2 ) underground, making it a low-cost "shovelready" solution to climate change. Its multiple co-benefits, including the production of healthy, nutritious food, means it will be a critical component of our response to rising climate instability.One of the buzzwords today is "sustainable." Everybody wants to be sustainable. My question is why in the world would we want to sustain a degraded resource? We need to work on regenerating our soils, not sustaining them.Gabe Brown, farmer and regenerative agriculture pioneer
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