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There has been a large push in education over the last decade to drive STEM learning interest during the formative years of adolescence through the usage of engaging computer science related initiatives such as computational makerspaces that allow students to design and build a wide array of personally connected artifacts. But for these initiatives to work, students must be interested in the journey, and the curricula that drive many of these programs are not often designed to be culturally relevant to many of the students they are aimed at motivating. This paper investigated how computational making curricula can be designed in a reflexive and culturally supportive manner by following the trajectory and tensions faced by a black middle school student as he makes his way through the first iteration of such a space. 

We explore the evolution of slow slip on the Cascadia megathrust during two large episodic tremor and slip events and compare stress changes to the spatial evolution of tremor from Pacific Northwest Seismic Network tremor locations. We used displacement time series from ~72 GPS stations, along with the Extended Network Inversion Filter to solve for the time‐dependent fault slip. The 2010 (Mw6.8) and 2012 (Mw6.8) events propagated northward and southward, respectively, allowing us to assess directional effects on slip behavior. We observed that tremor occurs on the leading edge of propagating slipping regions, well ahead of the highest slip rates, independent of the along‐strike propagation direction. Resolution tests using the actual tremor distributions to generate synthetic data show that our result of peak tremor rates leading peak slip rates is not due to biases introduced by temporal smoothing. Calculated stress changes due to the time‐dependent slip distributions imply that tremor is sensitive to kilopascals of stress, consistent with studies of tidally triggered tremor. Within the resolution of our model, our results are consistent with the hypothesis that significant tremor is triggered by stresses ahead of the highest slip rates. We also observe ongoing slip continuing several days after tremor has passed. Our observations are consistent with some numerical models of tremor patches that suggest that this behavior can be explained by densely packed asperities resulting in somewhat crack‐like propagation rather than a slip pulse that is as concentrated as the tremor activity.

 

Abstract The EXO-200 experiment searched for neutrinoless double-beta decay of 136 Xe with a single-phase liquid xenon detector. It used an active mass of 110 kg of 80.6%-enriched liquid xenon in an ultra-low background time projection chamber with ionization and scintillation detection and readout. This paper describes the design and performance of the various support systems necessary for detector operation, including cryogenics, xenon handling, and controls. Novel features of the system were driven by the need to protect the thin-walled detector chamber containing the liquid xenon, to achieve high chemical purity of the Xe, and to maintain thermal uniformity across the detector.