The Influence of Pre Coating Layers On Barrier Coatings

Layers of cellulose nanofibrils (CNF) on paper have been demonstrated to be an effective barrier against oxygen and grease and have been shown to improve the barrier performance of dispersion-based barrier coatings. The potential to produce paper grades that have good oxygen, grease, and moisture barrier properties is clear, but a good understanding of the synergies between CNF, other coating layers, and water-borne barrier coatings (WBBC) is not clear. Different coat weights of a WBBC were applied to papers that have a range of different qualities and amounts of the CNF layer on them. The same WBBC was also applied to conventionally pigmented coated paper, with various types of pigments and latex levels. Samples are characterized in terms of grease resistance, water vapor transmission rate (WVTR), and oxygen transmission rate before and after folding. When WBBC is applied on a CNF layer, the WVTR improves by more than a factor of ten compared to when a WBBC is applied to the base paper with no CNF layer. Similar improvement is also seen when the WBBC is applied to the pigmented coating layer. Folding decreases, the moisture barrier performance to some degree, but not grease when CNF is used

Arbitrage in Political Prediction Markets

Online prediction markets are a powerful tool for aggregating information and show promise as predictive tools for uncertain outcomes, from sporting events to election results. However, these markets only serve as effective prediction tools so long as the market pricing remains efficient. We analyze the potential arbitrage profits derived from such mispricings in two leading American political prediction markets, PredictIt (for the 2016 and 2020 elections) and the Iowa Electronic Markets (for the 2016 election), to quantify the degree of mispricing and to show how market design can contribute to price distortion. We show that contracts hosted by PredictIt, compared to the IEM, are chronically mispriced, with large arbitrage profits in the 2016 election markets and non-negligible profits for the 2020 markets. We discuss the role of profit fees and contract limits, the primary differences between the PredictIt and IEM, in distorting pricing on PredictIt by limiting the ability of traders to capture arbitrage profits. Additionally, we examine the association between arbitrage and margin-linking, increased liquidity, and the number of unique contracts PredictIt's markets. This research provides cautionary evidence of potential inefficiencies in prediction markets with the intention of improving market implementation and enhancing market predictiveness

Reply to Wassmann et al.: More data at high sampling intensity from medium- and intense-intermittently flooded rice farms is crucial

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.Here, we briefly respond to critique of our study (1) by Wassmann et al. (2). A detailed response to their letter is available online (edf.org/riceN2O)

High nitrous oxide fluxes from rice indicate the need to manage water for both long- and short-term climate impacts

Global rice cultivation is estimated to account for 2.5% of current anthropogenic warming because of emissions of methane (CH4), a short-lived greenhouse gas. This estimate assumes a widespread prevalence of continuous flooding of most rice fields and hence does not include emissions of nitrous oxide (N2O), a long-lived greenhouse gas. Based on the belief that minimizing CH4 from rice cultivation is always climate beneficial, current mitigation policies promote increased use of intermittent flooding. However, results from five intermittently flooded rice farms across three agroecological regions in India indicate that N2O emissions per hectare can be three times higher (33 kg-N2O⋅ha−1⋅season−1) than the maximum previously reported. Correlations between N2O emissions and management parameters suggest that N2O emissions from rice across the Indian subcontinent might be 30–45 times higher under intensified use of intermittent flooding than under continuous flooding. Our data further indicate that comanagement of water with inorganic nitrogen and/or organic matter inputs can decrease climate impacts caused by greenhouse gas emissions up to 90% and nitrogen management might not be central to N2O reduction. An understanding of climate benefits/drawbacks over time of different flooding regimes because of differences in N2O and CH4 emissions can help select the most climate-friendly water management regimes for a given area. Region-specific studies of rice farming practices that map flooding regimes and measure effects of multiple comanaged variables on N2O and CH4 emissions are necessary to determine and minimize the climate impacts of rice cultivation over both the short term and long term

Mercury isotopes in a forested ecosystem: Implications for air‐surface exchange dynamics and the global mercury cycle

Forests mediate the biogeochemical cycling of mercury (Hg) between the atmosphere and terrestrial ecosystems; however, there remain many gaps in our understanding of these processes. Our objectives in this study were to characterize Hg isotopic composition within forests, and use natural abundance stable Hg isotopes to track sources and reveal mechanisms underlying the cycling of Hg. We quantified the stable Hg isotopic composition of foliage, forest floor, mineral soil, precipitation, and total gaseous mercury (THg (g) ) in the atmosphere and in evasion from soil, in 10‐year‐old aspen forests at the Rhinelander FACE experiment in northeastern Wisconsin, USA. The effect of increased atmospheric CO 2 and O 3 concentrations on Hg isotopic composition was small relative to differences among forest ecosystem components. Precipitation samples had δ 202 Hg values of −0.74 to 0.06‰ and ∆ 199 Hg values of 0.16 to 0.82‰. Atmospheric THg (g) had δ 202 Hg values of 0.48 to 0.93‰ and ∆ 199 Hg values of −0.21 to −0.15‰. Uptake of THg (g) by foliage resulted in a large (−2.89‰) shift in δ 202 Hg values; foliage displayed δ 202 Hg values of −2.53 to −1.89‰ and ∆ 199 Hg values of −0.37 to −0.23‰. Forest floor samples had δ 202 Hg values of −1.88 to −1.22‰ and ∆ 199 Hg values of −0.22 to −0.14‰. Mercury isotopes distinguished geogenic sources of Hg and atmospheric derived sources of Hg in soil, and showed that precipitation Hg only accounted for ~16% of atmospheric Hg inputs. The isotopic composition of Hg evasion from the forest floor was similar to atmospheric THg (g) ; however, there were systematic differences in δ 202 Hg values and MIF of even isotopes (∆ 200 Hg and ∆ 204 Hg). Mercury evasion from the forest floor may have arisen from air‐surface exchange of atmospheric THg (g) , but was not the emission of legacy Hg from soils, nor re‐emission of wet‐deposition. This implies that there was net atmospheric THg (g) deposition to the forest soils. Furthermore, MDF of Hg isotopes during foliar uptake and air‐surface exchange of atmospheric THg (g) resulted in the release of Hg with very positive δ 202 Hg values to the atmosphere, which is key information for modeling the isotopic balance of the global mercury cycle, and may indicate a shorter residence time than previously recognized for the atmospheric mercury pool. Key points Atmospheric Hg was fractionated during uptake by foliage (‐2.89 permil δ202Hg) Hg evading from soil was from atmospheric Hg interaction with soil environment Air‐surface exchange of Hg releases Hg with positive δ202Hg to global reservoirPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97463/1/2011GB004202RRts04.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/97463/2/2011GB004202RRts05.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/97463/3/2011GB004202RRts01.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/97463/4/gbc20021.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/97463/5/2011GB004202RRts06.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/97463/6/2011GB004202RRts02.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/97463/7/2011GB004202RRts07.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/97463/8/2011GB004202RRts03.pd

Isotopic Variability of Mercury in Ore, Mine-Waste Calcine, and Leachates of Mine-Waste Calcine from Areas Mined for Mercury

The isotopic composition of mercury (Hg) was determined in cinnabar ore, mine-waste calcine (retorted ore), and leachates obtained from water leaching experiments of calcine from two large Hg mining districts in the U.S. This study is the first to report significant mass-dependent Hg isotopic fractionation between cinnabar ore and resultant calcine. Data indicate that δ202Hg values relative to NIST 3133 of calcine (up to 1.52‰) in the Terlingua district, Texas, are as much as 3.24‰ heavier than cinnabar (−1.72‰) prior to retorting. In addition, δ202Hg values obtained from leachates of Terlingua district calcines are isotopically similar to, or as much as 1.17‰ heavier than associated calcines, most likely due to leaching of soluble, byproduct Hg compounds formed during ore retorting that are a minor component in the calcines. As a result of the large fractionation found between cinnabar and calcine, and because calcine is the dominant source of Hg contamination from the mines studied, δ202Hg values of calcine may be more environmentally important in these mined areas than the primary cinnabar ore. Measurement of the Hg isotopic composition of calcine is necessary when using Hg isotopes for tracing Hg sources from areas mined for Hg, especially mine water runoff

Methylmercury degradation and exposure pathways in streams and wetlands impacted by historical mining

The authors acknowledge financial support from the National Science Foundation: EAR-1226741 (to M.B.S.) and EAR-1225630 (to J.D.B.).Monomethyl mercury (MMHg) and total mercury (THg) concentrations and Hg stable isotope ratios (δ202Hg and Δ199Hg) were measured in sediment and aquatic organisms from Cache Creek (California Coast Range) and Yolo Bypass (Sacramento Valley). Cache Creek sediment had a large range in THg (87 to 3870 ng/g) and δ202Hg (− 1.69 to − 0.20‰) reflecting the heterogeneity of Hg mining sources in sediment. The δ202Hg of Yolo Bypass wetland sediment suggests a mixture of high and low THg sediment sources. Relationships between %MMHg (the percent ratio of MMHg to THg) and Hg isotope values (δ202Hg and Δ199Hg) in fish and macroinvertebrates were used to identify and estimate the isotopic composition of MMHg. Deviation from linear relationships was found between %MMHg and Hg isotope values, which is indicative of the bioaccumulation of isotopically distinct pools of MMHg. The isotopic composition of pre-photodegraded MMHg (i.e., subtracting fractionation from photochemical reactions) was estimated and contrasting relationships were observed between the estimated δ202Hg of pre-photodegraded MMHg and sediment IHg. Cache Creek had mass dependent fractionation (MDF; δ202Hg) of at least − 0.4‰ whereas Yolo Bypass had MDF of + 0.2 to + 0.5‰. This result supports the hypothesis that Hg isotope fractionation between IHg and MMHg observed in rivers (− MDF) is unique compared to + MDF observed in non-flowing water environments such as wetlands, lakes, and the coastal ocean.PostprintPeer reviewe

Frost flowers growing in the Arctic ocean‐atmosphere–sea ice–snow interface: 2. Mercury exchange between the atmosphere, snow, and frost flowers

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95146/1/jgrd17360.pd

Mass dependent stable isotope fractionation of mercury during its microbial transformations

Mercury (Hg) is often cited in fish consumption advisories across the world due to the extreme neurotoxicity of its methylated forms. Given the complex biogeochemical cycling of Hg, a differentiation between local vs. global and natural vs. anthropogenic sources of Hg(0) and determination of transformations that are dominant in a given ecosystem is critical. Mercury has seven stable isotopes and Hg isotope ratios can become a novel biogeochemical tool to track sources and transformations of Hg in the environment. However, development of a stable isotope based tool requires the determination of the extent of fractionation during individual biotic and abiotic transformations that can occur in the environment. This thesis reports the extent of fractionation of Hg isotopes during two biological transformations: 1) degradation of monomethyl-Hg (MMHg) via the mercury resistance (mer) pathway in Escherichia coli JM109/pPB117 and 2) Hg(II) reduction by four Hg(II) reducing strains, including three Hg(II) resistant strains (E. coli JM109/pPB117, Bacillus cereus Strain 5 and Anoxybacillus spp. FB9) and a Hg(II) sensitive strain (Shewanella oneidensis MR-1). Using a multi-collector inductively coupled plasma mass spectrometer, it was found that MMHg and Hg(II) that remained in the reactors became progressively heavier (increasing delta202Hg) with time and underwent mass dependent Rayleigh-type fractionation with average fractionation factors (alpha 202/198 for reactant/instantaneous product) of 1.0004 and 1.0016, respectively. Mass independent fractionation (MIF) was not observed and based on the nature of microbe-Hg interactions, it is suggested that the nuclear spin dependent MIF is unlikely to occur during biological processes. A multi-step framework for understanding the extent of fractionation seen during the mer mediated MMHg degradation and Hg(II) reduction experiments is provided, and based on the biochemistry and kinetics of the steps involved in the two pathways, the steps in the process that could contribute to the observed extent of fractionation are suggested in the thesis. A clear effect of Hg(II) bioavailability on the extent of fractionation of Hg was observed and is also discussed. The framework discussed here can guide future experiments on Hg isotope fractionation during other transformations in its biogeochemical cycle, and ultimately facilitate a more rigorous development of a Hg isotope based geochemical tool.Ph.D.Includes bibliographical references (p. 140-151)by Krite

MeHg photoreduction rates and stable isotope enrichment from mercury reduction experiments conducted on marine phytoplankton from 2012-2013.

Dataset: ISOMeHg RatesMeHg photoreduction rates and stable isotope enrichment from mercury reduction experiments conducted on marine phytoplankton from 2012-2013. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/826633NSF Division of Ocean Sciences (NSF OCE) OCE-163415