1,624 research outputs found
Canadian Theatre and the Tragic Experience of Evil
This essay examines the relevance of the tragic account of evil for Canadian theatre in the shadow of the contemporary "war on terror." It concentrates on two important aspects of the ancient Greek depiction of evil in tragedy: (1) that no agent, human or divine, is either absolutely good or absolutely evil; and (2) that evil, understood as the experience of dread, cannot be exterminated but can, at best, be kept within limits. In other words, the tragic account of evil is neither"melodramatic" nor"eschatological." The essay then discusses three recent Canadian plays that address current moral and geo-political issues: The Adventures of Ali & Ali and the aXes of Evil by Marcus Youssef, Guillermo Verdecchia, and Camyar Chai; Capture Me by Judith Thompson; and Insomnia by Daniel Brooks with Guillermo Verdecchia. Through these works, this essay explores how the experience of evil is currently being depicted and considers the possibilities for a new type of tragic theatre in Canada.
Résumé
Cet article a pour but d’examiner la pertinence de la représentation tragique du mal dans le théâtre canadien au regard de la guerre contemporaine contre le terrorisme. Il se concentre sur deux aspects importants de la représentation du mal dans le théâtre grec antique, soit : (1) qu’aucun agent, humain ou divin, n’est entièrement bon ou mauvais et (2) que le « mal, » c’est-à -dire l'expérience de la terreur, ne peut pas être détruite mais peut, au mieux, être limitée. En d’autres mots, la représentation tragique du mal n’est ni « mélodramatique, » ni « eschatologique. » L’article, par la suite, examine trois oeuvres canadiennes récentes qui traitent des questions morales et des problèmes géopolitiques contemporains, soit : The Adventures of Ali & Ali and the aXes of Evil de Marcus Youssef, Guillermo Verdecchia et Camyar Chai; Capture Me de Judith Thompson; et Insomnia de Daniel Brooks et Guillermo Verdecchia. À l’aide de ces œuvres, l’article étudie les possibilités d’avoir un nouveau genre de théâtre tragique au Canada, aborde la question de la représentation contemporaine de l’expérience du « mal »
U.S. LNG in transition: An analysis of supply chain emissions from the nation’s largest export facility and potential for abatement.
Exporters of liquefied natural gas face growing pressure from buyers and end-user nations to address supply-chain emissions of greenhouse gases. This pressure has led to the trade of “carbon-neutral LNG cargoes,” which involves accounting for emissions associated with a cargo that customers can then use to purchase carbon offsets. However, analyzing supply chain emissions remains a significant challenge in the absence of more accurate emissions monitoring or an industry-wide standard for estimating emissions.
This research paper uses a framework adopted in the first trade of a “carbon neutral cargo” sourced from the largest U.S. LNG export facility, Cheniere’s Sabine Pass LNG terminal, to produce a new estimate of annual emissions associated with U.S. LNG exports before the point of export. The result provides a useful reference point for analyzing domestic supply chain emissions associated with the sector.
Next, the Sabine Pass facility is used as a case study to analyze facility-level emissions. Estimates of annual facility-level emissions at the terminal are shown to be about 41% higher than what official U.S. government inventories estimate. The research then turns to an economic analysis of deploying carbon capture and storage at Sabine Pass to abate estimated emissions. This analysis shows that incremental operating cash flow before debt repayment could become positive in 2030 with proposed increases to carbon-capture-and-storage incentives under the Section 45Q tax credit that U.S. lawmakers are considering at the time of this writing. If credits could cover operational expenses, justifying a $4 billion capital cost of carbon capture and storage could depend on a combination of Cheniere’s ability to bring in additional revenue as a result of a competitive advantage gained through the abatement investment and on the value to the company of avoiding risks such as the potential for stranded assets
Persistent topographic development along a strike-slip fault system: The Mount McKinley restraining bend
The Denali Fault is a major strike-slip fault extending from British Colombia, into western Alaska. Mount McKinley, at 6,114 m, is the highest peak in North America and is located to the south of a bend in the Denali Fault (Fig.1). To the north, at the apex of the bend in the fault, Peters Dome (3,221 m) is the highest peak and north-side peak elevations rapidly decrease moving away from the bend’s apex
Model-based determination of the synchronization delay between MRI and trajectory data.
PURPOSE: Real-time monitoring of dynamic magnetic fields has recently become a commercially available option for measuring MRI k-space trajectories and magnetic fields induced by eddy currents in real time. However, for accurate image reconstructions, sub-microsecond synchronization between the MRI data and field dynamics (ie, k-space trajectory plus other spatially varying fields) is required. In this work, we introduce a new model-based algorithm to automatically perform this synchronization using only the MRI data and field dynamics.
METHODS: The algorithm works by enforcing consistency among the MRI data, field dynamics, and receiver sensitivity profiles by iteratively alternating between convex optimizations for (a) the image and (b) the synchronization delay. A healthy human subject was scanned at 7 T using a transmit-receive coil with integrated field probes using both single-shot spiral and EPI, and reconstructions with various synchronization delays were compared with the result of the proposed algorithm. The accuracy of the algorithm was also investigated using simulations, in which the acquisition delays for simulated acquisitions were determined using the proposed algorithm and compared with the known ground truth.
RESULTS: In the in vivo scans, the proposed algorithm minimized artifacts related to synchronization delay for both spiral and EPI acquisitions, and the computation time required was less than 30 s. The simulations demonstrated accuracy to within tens of nanoseconds.
CONCLUSIONS: The proposed algorithm can automatically determine synchronization delays between MRI data and field dynamics measured using a field probe system
Model-based determination of the synchronization delay between MRI and trajectory data.
PURPOSE: Real-time monitoring of dynamic magnetic fields has recently become a commercially available option for measuring MRI k-space trajectories and magnetic fields induced by eddy currents in real time. However, for accurate image reconstructions, sub-microsecond synchronization between the MRI data and field dynamics (ie, k-space trajectory plus other spatially varying fields) is required. In this work, we introduce a new model-based algorithm to automatically perform this synchronization using only the MRI data and field dynamics.
METHODS: The algorithm works by enforcing consistency among the MRI data, field dynamics, and receiver sensitivity profiles by iteratively alternating between convex optimizations for (a) the image and (b) the synchronization delay. A healthy human subject was scanned at 7 T using a transmit-receive coil with integrated field probes using both single-shot spiral and EPI, and reconstructions with various synchronization delays were compared with the result of the proposed algorithm. The accuracy of the algorithm was also investigated using simulations, in which the acquisition delays for simulated acquisitions were determined using the proposed algorithm and compared with the known ground truth.
RESULTS: In the in vivo scans, the proposed algorithm minimized artifacts related to synchronization delay for both spiral and EPI acquisitions, and the computation time required was less than 30 s. The simulations demonstrated accuracy to within tens of nanoseconds.
CONCLUSIONS: The proposed algorithm can automatically determine synchronization delays between MRI data and field dynamics measured using a field probe system
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Sorting Out a Promiscuous Superfamily: Towards Cadherin Connectomics
Members of the cadherin superfamily of proteins are involved in diverse biological processes such as morphogenesis, sound transduction, and neuronal connectivity. Key to cadherin function is their extracellular domain containing cadherin repeats, which can mediate interactions involved in adhesion and cell signaling. Recent cellular, biochemical, and structural studies have revealed that physical interaction among cadherins is more complex than originally thought. Here we review work on new cadherin complexes and discuss how the classification of the mammalian family can be used to search for additional cadherin-interacting partners. We also highlight some of the challenges in cadherin research; namely, the characterization of a cadherin connectome in biochemical and structural terms, as well as the elucidation of molecular mechanisms underlying the functional diversity of nonclassical cadherins in vivo.Molecular and Cellular Biolog
High-entropy high-hardness metal carbides discovered by entropy descriptors
High-entropy materials have attracted considerable interest due to the
combination of useful properties and promising applications. Predicting their
formation remains the major hindrance to the discovery of new systems. Here we
propose a descriptor - entropy forming ability - for addressing
synthesizability from first principles. The formalism, based on the energy
distribution spectrum of randomized calculations, captures the accessibility of
equally-sampled states near the ground state and quantifies configurational
disorder capable of stabilizing high-entropy homogeneous phases. The
methodology is applied to disordered refractory 5-metal carbides - promising
candidates for high-hardness applications. The descriptor correctly predicts
the ease with which compositions can be experimentally synthesized as rock-salt
high-entropy homogeneous phases, validating the ansatz, and in some cases,
going beyond intuition. Several of these materials exhibit hardness up to 50%
higher than rule of mixtures estimations. The entropy descriptor method has the
potential to accelerate the search for high-entropy systems by rationally
combining first principles with experimental synthesis and characterization.Comment: 12 pages, 2 figure
Characterization and correction of time-varying eddy currents for diffusion MRI
Purpose: To develop and test a method for reducing artifacts due to time-varying eddy currents in oscillating gradient spin-echo (OGSE) diffusion images. Methods: An in-house algorithm (TVEDDY), that for the first time retrospectively models eddy current decay, was tested on pulsed gradient spin echo and OGSE brain images acquired at 7 T. Image pairs were acquired using opposite polarity diffusion gradients. A three-parameter exponential decay model (two amplitudes and a time constant) was used to characterize and correct eddy current distortions by minimizing the intensity difference between image pairs. Correction performance was compared with conventional correction methods by evaluating the mean squared error (MSE) between diffusion-weighted images acquired with opposite polarity diffusion gradients. As a ground-truth comparison, images were corrected using field dynamics up to third order in space, measured using a field monitoring system. Results: Time-varying eddy currents were observed for OGSE, which introduced blurring that was not reduced using the traditional approach but was diminished considerably with TVEDDY and field monitoring–informed model-based reconstruction. No MSE difference was observed between the conventional approach and TVEDDY for pulsed gradient spin echo, but for OGSE TVEDDY resulted in significantly lower MSE than the conventional approach. The field-monitoring reconstruction had the lowest MSE for both pulsed gradient spin echo and OGSE. Conclusion: This work establishes that it is possible to estimate time-varying eddy currents from the actual diffusion data, which provides substantial image-quality improvements for gradient-intensive diffusion MRI acquisitions like OGSE
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