Published: Thu, 30 Mar 2017 17:07:49 GMTCopyright: Public Domain
Thu, 30 Mar 2017 16:49:03 GMTThis letter presents our rationale for promoting pluralism in methods to capture peoples values associated with changes in ecosystems services, some of which do not involve monetization.
Thu, 30 Mar 2017 15:03:52 GMTThis draft ISA document represents a concise synthesis and evaluation of the most policy-relevant science and will ultimately provide the scientific bases for EPA’s decision on retaining or revising the current secondary standards for NO2, SO2, PM 2.5 and PM 10 since the prior release of the assessment.
Thu, 30 Mar 2017 14:02:21 GMTAttrition behavior and particle loss of a copper oxide-based oxygen carrier from a methane chemical looping combustion (CLC) process was investigated in a fluidized bed reactor. The aerodynamic diameters of most elutriated particulates, after passing through a horizontal settling duct, range between 2 and 5 μm. A notable number of submicron particulates are also identified. Oxygen carrier attrition was observed to lead to increased CuO loss resulting from the chemical looping reactions, i.e., Cu is enriched in small particles generated primarily from fragmentation in the size range of 10-75 μm. Cyclic reduction and oxidation reactions in CLC have been determined to weaken the oxygen carrier particles, resulting in increased particulate emission rates when compared to oxygen carriers without redox reactions. The generation rate for particulates < 10 μm was found to decrease with progressive cycles over as-prepared oxygen carrier particles and then reach a steady state. The surface of the oxygen carrier is also found to be coarsened due to a Kirkendall effect, which also explains the enrichment of Cu on particle surfaces and in small particles. As a result, it is important to collect and reprocess small particles generated from chemical looping processes to reduce oxygen carrier loss.
Thu, 30 Mar 2017 13:09:20 GMTMany studies of animal responses to ocean acidification focus on uniformly conditioned age cohorts that lack complexities typically found in wild populations. These studies have become the primary data source for predicting higher level ecological effects, but the roles of intraspecific interactions in re-shaping biological, demographic and evolutionary responses are not commonly considered. To explore this problem, I assessed responses in the mysid Americamysis bahia to bubbling of CO2-enriched and un-enriched air into the seawater supply in flow-through aquariums. I conducted one experiment using isolated age cohorts and a separate experiment using intact populations. The seawater supply was continuously input from Narragansett Bay (Rhode Island, USA). The 28-day cohort study was maintained without resource or spatial limitations, whereas the 5-month population study consisted of stage-structured populations that were allowed to self-regulate. These differences are common features of experiments and were intentionally retained to demonstrate the effect of methodological approaches on perceptions of effect mechanisms. The CO2 treatment reduced neonate abundance in the cohort experiment (24% reduction due to a mean pH difference of −0.27) but not in the population experiment, where effects were small and were strongest for adult and stage 1 survival (3% change due to a mean pH difference of −0.25). I also found evidence of competition in the population experiment, further complicating relationships with cohort experiments. These results point to limitations of standard cohort tests. Such experiments should be complimented by studies of intact populations where responses may be affected by evolution, acclimation, and competition.
Thu, 30 Mar 2017 12:27:38 GMTTechnical Brief