391 research outputs found

    Amending the National Environmental Policy Act: Federal Environmental Protection in the Twenty-First Century

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    The National Environmental Policy Act (NEPA) represents the cornerstone of American environmental law and marks the beginning of the environmental law statutory movement in the United States. This Article traces the evolution of NEPA and the environmental movement and describes the framers\u27 intent in passing NEPA. Next, the Article examines judicial and executive interpretations of NEPA. The Article concludes by assessing NEPA\u27s present state and suggesting possible reforms to ensure a strong future commitment to NEPA

    Structure of Flame Balls at Low Lewis-Number

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    The Structure of Flame Balls at Low Lewis-Number (SOFBALL) experiment explored the behavior of a newly discovered flame phenomena called "flame balls." These spherical, stable, stationary flame structures, observed only in microgravity, provide a unique opportunity to study the interactions of the two most important processes necessary for combustion (chemical reaction and heat and mass transport) in the simplest possible configuration. The previously unobtainable experimental data provided a comparison with models of flame stability and flame propagation limits that are crucial both in assessing fire safety and in designing efficient, clean-burning combustion engines

    Detecting scale-induced overflow bugs in production HPC codes

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    Structure of Flame Balls at Low Lewis-Number (SOFBALL): Preliminary Results From the STS-83 and STS-94 Space Flight Experiments

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    Results from the Structure Of Flame Balls At Low Lewis-number (SOFBALL) space flight experiment conducted on the MSL-1 Space Shuttle missions are reported. Several new insights were obtained, including: much lower buoyancy-induced drift speed than anticipated pre-flight; repulsion of adjacent flame balls due to their mutual interaction; remarkable sensitivity of flame balls to small accelerations resulting from Orbiter attitude control maneuvers; and very similar net heat release for all flame balls in all mixtures tested. Comparison of experimental results to computational predictions reveals limitations in current models of H2-02 chemistry for very lean mixtures. It is discussed how the results of these space experiments may provide an improved understanding of the interactions of the two most important phenomena in combusting materials, namely chemical reaction and transport processes, in the unequivocally simplest possible configuration

    MerA functions as a hypothiocyanous acid reductase and defense mechanism in Staphylococcus aureus

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    The major pathogen Staphylococcus aureus has to cope with host-derived oxidative stress to cause infections in humans. Here, we report that S. aureus tolerates high concentrations of hypothiocyanous acid (HOSCN), a key antimicrobial oxidant produced in the respiratory tract. We discovered that the flavoprotein disulfide reductase (FDR) MerA protects S. aureus from this oxidant by functioning as a HOSCN reductase, with its deletion sensitizing bacteria to HOSCN. Crystal structures of homodimeric MerA (2.4 Å) with a Cys43–Cys48 intramolecular disulfide, and reduced MerACys43S (1.6 Å) showed the FAD cofactor close to the active site, supporting that MerA functions as a group I FDR. MerA is controlled by the redox-sensitive repressor HypR, which we show to be oxidized to intermolecular disulfides under HOSCN stress, resulting in its inactivation and derepression of merA transcription to promote HOSCN tolerance. Our study highlights the HOSCN tolerance of S. aureus and characterizes the structure and function of MerA as a major HOSCN defense mechanism. Crippling the capacity to respond to HOSCN may be a novel strategy for treating S. aureus infections

    Structural insights into the mechanism of archaellar rotational switching

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    Signal transduction via phosphorylated CheY towards the flagellum and the archaellum involves a conserved mechanism of CheY phosphorylation and subsequent conformational changes within CheY. This mechanism is conserved among bacteria and archaea, despite substantial differences in the composition and architecture of archaellum and flagellum, respectively. Phosphorylated CheY has higher affinity towards the bacterial C-ring and its binding leads to conformational changes in the flagellar motor and subsequent rotational switching of the flagellum. In archaea, the adaptor protein CheF resides at the cytoplasmic face of the archaeal C-ring formed by the proteins ArlCDE and interacts with phosphorylated CheY. While the mechanism of CheY binding to the C-ring is well-studied in bacteria, the role of CheF in archaea remains enigmatic and mechanistic insights are absent. Here, we have determined the atomic structures of CheF alone and in complex with activated CheY by X-ray crystallography. CheF forms an elongated dimer with a twisted architecture. We show that CheY binds to the C-terminal tail domain of CheF leading to slight conformational changes within CheF. Our structural, biochemical and genetic analyses reveal the mechanistic basis for CheY binding to CheF and allow us to propose a model for rotational switching of the archaellum. Signal transduction via phosphorylated CheY is conserved in bacteria and archaea. In this study, the authors employ structural biochemistry combined with cell biology to delineate the mechanism of CheY recognition by the adaptor protein CheF

    Automatic analysis of facilitated taste-liking

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    This paper focuses on: (i) Automatic recognition of taste-liking from facial videos by comparatively training and evaluating models with engineered features and state-of-the-art deep learning architectures, and (ii) analysing the classification results along the aspects of facilitator type, and the gender, ethnicity, and personality of the participants. To this aim, a new beverage tasting dataset acquired under different conditions (human vs. robot facilitator and priming vs. non-priming facilitation) is utilised. The experimental results show that: (i) The deep spatiotemporal architectures provide better classification results than the engineered feature models; (ii) the classification results for all three classes of liking, neutral and disliking reach F1 scores in the range of 71%-91%; (iii) the personality-aware network that fuses participants’ personality information with that of facial reaction features provides improved classification performance; and (iv) classification results vary across participant gender, but not across facilitator type and participant ethnicity.EPSR

    Simulation of an SO2 tolerant amine based post-combustion CO2 capture process

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    Removal of multiple contaminants from flue gas streams in a single process step offers the potential to lower the cost of emissions reduction technologies. An example is the CS-Cap process, developed by CSIRO, which removes both the SO2 and CO2 from combustion flue gases. In order to further develop this process, a rate based simulation is required of not only the CO2 capture section, but also the absorption of SO2 into aqueous amine absorbents. ProTreat® simulation software was used to simulate CSIRO's Loy Yang CO2 capture pilot plant. This pilot plant has previously been used for proof-of-concept operation of the CS-Cap process. The model simulates various scenarios and flue gas conditions to determine the effect on the operating requirements of the SO2 capture stage. It reveals that the recirculating absorbent flow rates required in the SO2 capture loop are of similar magnitude to those required in the CO2 capture stage. Manipulating the operating parameters of the SO2 capture section will affect the properties, particularly sulfate concentration, of the slip stream sent for disposal/treatment. This could potentially allow the properties of the waste stream to be tailored for the particular downstream treatment used. In addition, condensation of water from the inlet flue gas stream is identified as an issue requiring further investigation. © Copyright 2018, AIDIC Servizi S.r.l
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