2,521 research outputs found

    Product-Related Risk and Cognitive Biases: The Shortcomings of Enterprise Liability

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    Products liability law has witnessed a long debate over whether manufacturers should be held strictly liable for the injuries that products cause. Recently, some have argued that psychological research on human judgment supports adopting a regime of strict enterprise liability for injuries caused by product design. These new proponents of enterprise liability argue that the current system, in which manufacturer liability for product design turns on the manufacturer\u27s negligence, allows manufacturers to induce consumers into undertaking inefficiently dangerous levels or types of consumption. In this paper we argue that the new proponents of enterprise liability have: (1) not provided any more than anecdotal evidence for their thesis; (2) failed to account for the mechanisms the law already has available to counter manufacturer manipulation of consumers; and (3) made no effort to address the well-known problems enterprise liability creates. Furthermore, even on its own terms, the new arguments for enterprise liability fail to consider the tendency of some manufacturers to exacerbate the risks that some products pose - a tendency that enterprise liability would exacerbate. In short, the insights gleaned from psychological research on human judgment do not support adopting a system of strict enterprise liability for products

    Synchrotron study of poly[[di-μ-aqua­(μ-2,2′-bipyridyl-5,5′-dicarboxyl­ato)di­potassium] dihydrate]

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    The title compound, {[K2(C12H6N2O4)(H2O)2]·2H2O}n, forms a three-dimensional coordination polymer in the solid state. The asymmetric unit consists of one K+ ion, half of a 2,2′-bipyridyl-5,5′-dicarboxyl­ate ligand, one coordinated water mol­ecule and one solvent water mol­ecule. The K+ ion is 7-coordinated by the oxygen atoms of two water mol­ecules and by five oxygen atoms of four carboxyl­ate groups, one of which is chelating. The extended structure can be described as a binodal network in which each K+ is a six-connected node, bonding to four carboxyl­ate groups and two bridging water mol­ecules, and the 2,2′-bipyridyl-5,5′-dicarboxyl­ate linkers are eight-connected nodes, with each carboxyl­ate group bridging four metal centers. Overall, this arrangement generates a complex network with point symbol {34.412.512}{34.44.54.63}2. Both of the bridging water mol­ecules participate as donors in hydrogen-bonding inter­actions; one to solvent water mol­ecules and a second to an oxygen atom of a carboxyl­ate group

    The effect of convalescent plasma therapy on mortality among patients with COVID-19: Systematic review and meta-analysis

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    To determine the effect of COVID-19 convalescent plasma on mortality, we aggregated patient outcome data from 10 randomized clinical trials, 20 matched control studies, 2 dose-response studies, and 96 case reports or case series. Studies published between January 1, 2020, and January 16, 2021, were identified through a systematic search of online PubMed and MEDLINE databases. Random effects analyses of randomized clinical trials and matched control data demonstrated that patients with COVID-19 transfused with convalescent plasma exhibited a lower mortality rate compared with patients receiving standard treatments. Additional analyses showed that early transfusion (within 3 days of hospital admission) of higher titer plasma is associated with lower patient mortality. These data provide evidence favoring the efficacy of human convalescent plasma as a therapeutic agent in hospitalized patients with COVID-19

    Convalescent plasma therapy for COVID-19: A graphical mosaic of the worldwide evidence

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    Convalescent plasma has been used worldwide to treat patients hospitalized with coronavirus disease 2019 (COVID-19) and prevent disease progression. Despite global usage, uncertainty remains regarding plasma efficacy, as randomized controlled trials (RCTs) have provided divergent evidence regarding the survival benefit of convalescent plasma. Here, we argue that during a global health emergency, the mosaic of evidence originating from multiple levels of the epistemic hierarchy should inform contemporary policy and healthcare decisions. Indeed, worldwide matched-control studies have generally found convalescent plasma to improve COVID-19 patient survival, and RCTs have demonstrated a survival benefit when transfused early in the disease course but limited or no benefit later in the disease course when patients required greater supportive therapies. RCTs have also revealed that convalescent plasma transfusion contributes to improved symptomatology and viral clearance. To further investigate the effect of convalescent plasma on patient mortality, we performed a meta-analytical approach to pool daily survival data from all controlled studies that reported Kaplan-Meier survival plots. Qualitative inspection of all available Kaplan-Meier survival data and an aggregate Kaplan-Meier survival plot revealed a directionally consistent pattern among studies arising from multiple levels of the epistemic hierarchy, whereby convalescent plasma transfusion was generally associated with greater patient survival. Given that convalescent plasma has a similar safety profile as standard plasma, convalescent plasma should be implemented within weeks of the onset of future infectious disease outbreaks

    Deconvoluting heme biosynthesis to target blood-stage malaria parasites

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    Heme metabolism is central to blood-stage infection by the malaria parasite Plasmodium falciparum. Parasites retain a heme biosynthesis pathway but do not require its activity during infection of heme-rich erythrocytes, where they can scavenge host heme to meet metabolic needs. Nevertheless, heme biosynthesis in parasite-infected erythrocytes can be potently stimulated by exogenous 5-aminolevulinic acid (ALA), resulting in accumulation of the phototoxic intermediate protoporphyrin IX (PPIX). Here we use photodynamic imaging, mass spectrometry, parasite gene disruption, and chemical probes to reveal that vestigial host enzymes in the cytoplasm of Plasmodium-infected erythrocytes contribute to ALA-stimulated heme biosynthesis and that ALA uptake depends on parasite-established permeability pathways. We show that PPIX accumulation in infected erythrocytes can be harnessed for antimalarial chemotherapy using luminol-based chemiluminescence and combinatorial stimulation by low-dose artemisinin to photoactivate PPIX to produce cytotoxic reactive oxygen. This photodynamic strategy has the advantage of exploiting host enzymes refractory to resistance-conferring mutations. DOI: http://dx.doi.org/10.7554/eLife.09143.00

    Traffic Aware Planner for Cockpit-Based Trajectory Optimization

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    The Traffic Aware Planner (TAP) software application is a cockpit-based advisory tool designed to be hosted on an Electronic Flight Bag and to enable and test the NASA concept of Traffic Aware Strategic Aircrew Requests (TASAR). The TASAR concept provides pilots with optimized route changes (including altitude) that reduce fuel burn and/or flight time, avoid interactions with known traffic, weather and restricted airspace, and may be used by the pilots to request a route and/or altitude change from Air Traffic Control. Developed using an iterative process, TAP's latest improvements include human-machine interface design upgrades and added functionality based on the results of human-in-the-loop simulation experiments and flight trials. Architectural improvements have been implemented to prepare the system for operational-use trials with partner commercial airlines. Future iterations will enhance coordination with airline dispatch and add functionality to improve the acceptability of TAP-generated route-change requests to pilots, dispatchers, and air traffic controllers

    Initial Implementation and Operational Use of TASAR in Alaska Airlines Flight Operations

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    NASA has been developing and testing the Traffic Aware Strategic Aircrew Requests (TASAR) concept for aircraft operations featuring a NASA-developed cockpit automation tool, the Traffic Aware Planner (TAP), which computes route changes compatible with nearby traffic and airspace constraints to improve flight efficiency. The TAP technology is anticipated to save fuel, flight time, and operating costs and thereby provide immediate and pervasive benefits to the aircraft operator. Alaska Airlines is partnered with NASA to implement and evaluate TASAR in revenue service. This paper will describe activities undertaken to achieve TASAR operational status at Alaska Airlines, and it will present preliminary results from initial flight operations

    Perceived Noise Analysis for Offset Jets Applied to Commercial Supersonic Aircraft

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    A systems analysis was performed with experimental jet noise data, engineaircraft performance codes and aircraft noise prediction codes to assess takeoff noise levels and mission range for conceptual supersonic commercial aircraft. A parametric study was done to identify viable engine cycles that meet NASAs N+2 goals for noise and performance. Model scale data from offset jets was used as input to the aircraft noise prediction code to determine the expected sound levels for the lateral certification point where jet noise dominates over all other noise sources. The noise predictions were used to determine the optimal orientation of the offset nozzles to minimize the noise at the lateral microphone location. An alternative takeoff procedure called programmed lapse rate was evaluated for noise reduction benefits. Results show there are two types of engines that provide acceptable range performance; one is a standard mixed-flow turbofan with a single-stage fan, and the other is a three-stream variable-cycle engine with a multi-stage fan. The engine with a single-stage fan has a lower specific thrust and is 8 to 10 EPNdB quieter for takeoff. Offset nozzles reduce the noise directed toward the thicker side of the outer flow stream, but have less benefit as the core nozzle pressure ratio is reduced and the bypass-to-core area ratio increases. At the systems level for a three-engine N+2 aircraft with full throttle takeoff, there is a 1.4 EPNdB margin to Chapter 3 noise regulations predicted for the lateral certification point (assuming jet noise dominates). With a 10 reduction in thrust just after takeoff rotation, the margin increases to 5.5 EPNdB. Margins to Chapter 4 and Chapter 14 levels will depend on the cumulative split between the three certification points, but it appears that low specific thrust engines with a 10 reduction in thrust (programmed lapse rate) can come close to meeting Chapter 14 noise levels. Further noise reduction is possible with additional reduction in takeoff thrust using programmed lapse rate, but studies are needed to investigate the practical limits for safety and takeoff regulations
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