Methane (CH 4) and carbon monoxide (CO) mixing ratios were measured at an air quality monitoring station near the Mt. Wilson (MW) Observatory in southern California starting in the spring of 2007. Diurnal variation and mixing ratio correlation (R 2 ¼ 0.81) were observed. The correlation results observed agree with previous aircraft measurements collected over the greater Los Angeles (LA) metropolitan area. The consistent agreement between CH 4 and CO indicates these gases are well-mixed before reaching the sampling site and the emission source contributions of both compounds are reasonably constant. Since CH 4 and CO are considered non-reactive on the time scale of dispersion within the LA urban area and their emission sources are likely to be similarly distributed (e.g., associated with human activities) they are subject to similar scales of atmospheric transport and dilution. This behavior allows the relationship of CH 4 and CO to be applied for estimation of CH 4 emissions using well-documented CO emissions. Applying this relationship a ''top-down'' CH 4 inventory was calculated for LA County based on the measurements observed at MW and compared with the California Air Resources Board (CARB) ''bottom-up'' CH 4 emissions inventory based on the Intergovernmental Panel on Climate Change recommended methodologies. The ''top-down'' CH 4 emissions inventory is approximately onethird greater than CARB's ''bottom-up'' inventory for LA County. Considering the uncertainties in both methodologies, the different CH 4 emissions inventory approaches are in good agreement, although some under and/or uninventoried CH 4 sources may exist.

Abstract:The possibility of reducing greenhouse gas (GHG) emissions by ruminants using improved grazing is investigated by estimating GHG emissions for cow-calf farms under light continuous (LC), heavy continuous (HC) and rotational grazing, also known as multi-paddock (MP), management strategies in Southern Great Plain (SGP) using life cycle assessment (LCA). Our results indicated a GHG emission with these grazing treatments of 8034.90 kg·CO2e·calffor cow-calf farms in SGP region, which is high, compared to that for other regions, due to the high percentage (79.6%) of enteric CH4 emissions caused by relatively lower feed quality on the unfertilized rangeland. Sensitivity analyses on MP grazing strategy showed that an increase in grass quality and digestibility could potentially reduce GHG emission by 30%. Despite higher GHG emissions on a per calf basis, net GHG emissions in SGP region are potentially negative when carbon (C) sequestration is taken into account. With net C emission rates of −2002.8, −1731.6 and −89.5 kg C ha −1 ·year −1 after converting from HC to MP, HC to LC and from LC to MP, our analysis indicated cow-calf farms converting from continuous to MP grazing in SGP region are likely net carbon sinks for decades.

FXR signaling activates the IRE1α/XBP1 pathway in vivo and in vitro. FXR pathway activation increases XBP1 splicing and enhances p-IRE1α expression. These effects are mediated, at least in part, by SHP. IRE1α/XBP1 pathway activation by bile acids and pharmacological FXR agonists may be protective during liver injury and may have therapeutic implications for liver diseases. (Hepatology 2018;68:304-316).

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Core Ideas Stabilized urea improved wheat grain yield and protein in the Southern Plains.Stabilized urea at a higher rate brought higher net profits than untreated urea at all price points.A safe seed‐placed rate for polymer‐coated urea in regional wheat is lower than 30 kg N ha–1.No benefit was observed in splitting nitrogen application in this study. In no‐till wheat (Triticum aestivum L.) cropping systems of the US Southern Great Plains, urea fertilizer is commonly surface broadcast and producers rely on unpredictable precipitation in dryland conditions for incorporation into the soil. Several enhanced‐efficiency fertilizer technologies are designed to reduce N loss in this scenario, though there are not published reports on evaluations of these in regional wheat systems. Here we report on an evaluation of two enhanced‐efficiency fertilizer technologies, polymer‐coated urea (PCU) and urease/nitrification inhibitor‐stabilized urea (SU), which were compared to untreated urea at different application rates (0, 31.5, and 70 kg N ha−1) and timings (at‐planting and split) in two locations differing in soil type (clay loam and loamy fine sand). The fertilizer was broadcast, except for PCU, which was drilled in‐row. The greatest yield was observed with a high at‐planting rate of SU, where yield was 26% greater than with untreated urea and 34% greater than with no fertilizer. Yield improvement with SU was associated with greater grain N uptake efficiency and protein content. The high SU rate brought higher net profits than untreated urea at all price points analyzed and surpassed the no‐fertilizer control as price increased. As might be expected with seed placement, there was substantial crop damage at the high rate of PCU, but even minor damage at the lower rate. The results suggest that a safe seed‐placed rate for PCU in wheat in this environment is somewhat lower than 30 kg N ha−1. No benefit was observed in splitting the N application.