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Title: RivFishTIME: A global database of fish time‐series to study global change ecology in riverine systems
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  1. null (Ed.)
    The United Nations recognizes reducing the effects of global warming as a Sustainable Development Goal (SDG) (#13). This goal is interconnected and critical to improving health and education, reducing inequality, and spurring economic growth globally. Civil engineers will play a vital role in meeting this goal. To understand how civil engineering students perceive global warming, we surveyed a national sample of civil engineering students in their final semester of college (n = 524). We asked them (a) if they recognize both the technical and social issues associated with global warming and (b) when they believe global warming will start to have a severe effect on themselves, others, and the planet. Civil engineering students are significantly more likely to recognize the technical issues associated with global warming than social issues. In particular, the majority of students understand global warming is an immediate issue for the environment, engineering, health, and science, but less than half recognize global warming presents social justice, poverty, and national security issues. Moreover, civil engineering students hold an inverse relationship between spatial distance and the timing of the effects of global warming. The majority of students believe global warming is currently having a severe impact on plant and animal species, the environment, people in developing countries, and the world's poor but do not recognize themselves in this group. Instead, civil engineering students predominantly believe the effects of global warming will start to have a serious impact on themselves, their family, and people in their community in 25 to 50 years. These results are troubling because if those beliefs translate into students waiting to address climate change for another two to five decades locks in more emissions and increases the chance of future and more severe global humanitarian crises. Educational interventions are needed to change these perspectives about time and impact. 
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  2. null (Ed.)
    Abstract. The formation of inorganic nitrate is the main sink for nitrogenoxides (NOx = NO + NO2). Due to the importance of NOx forthe formation of tropospheric oxidants such as the hydroxyl radical (OH) andozone, understanding the mechanisms and rates of nitrate formation isparamount for our ability to predict the atmospheric lifetimes of mostreduced trace gases in the atmosphere. The oxygen isotopic composition ofnitrate (Δ17O(nitrate)) is determined by the relativeimportance of NOx sinks and thus can provide an observationalconstraint for NOx chemistry. Until recently, the ability to utilizeΔ17O(nitrate) observations for this purpose was hindered by ourlack of knowledge about the oxygen isotopic composition of ozone (Δ17O(O3)). Recent and spatially widespread observations of Δ17O(O3) motivate an updated comparison of modeled andobserved Δ17O(nitrate) and a reassessment of modeled nitrateformation pathways. Model updates based on recent laboratory studies ofheterogeneous reactions render dinitrogen pentoxide (N2O5)hydrolysis as important as NO2 + OH (both 41 %) for globalinorganic nitrate production near the surface (below 1 km altitude). Allother nitrate production mechanisms individually represent less than 6 %of global nitrate production near the surface but can be dominant locally.Updated reaction rates for aerosol uptake of NO2 result in significantreduction of nitrate and nitrous acid (HONO) formed through this pathway inthe model and render NO2 hydrolysis a negligible pathway for nitrateformation globally. Although photolysis of aerosol nitrate may haveimplications for NOx, HONO, and oxidant abundances, it does notsignificantly impact the relative importance of nitrate formation pathways.Modeled Δ17O(nitrate) (28.6±4.5 ‰)compares well with the average of a global compilation of observations (27.6±5.0 ‰) when assuming Δ17O(O3) = 26 ‰, giving confidence in the model'srepresentation of the relative importance of ozone versus HOx (= OH + HO2 + RO2) in NOx cycling and nitrate formation on theglobal scale. 
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