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1. Geochemical Variability Along the Northern East Pacific Rise: Coincident Source Composition and Ridge Segmentation

   https://doi.org/10.1029/2019GC008287  

   Mallick, Soumen; Salters, Vincent J. M.; Langmuir, Charles H. (April 2019, Geochemistry, Geophysics, Geosystems)

   Abstract New trace element abundances and isotope compositions for more than 100 mid‐ocean ridge basalts from 5.5°N to 19°N on the East Pacific Rise show step function variations in isotopic composition along the ridge axis that coincide with ridge discontinuities. Transform faults, overlapping spreading centers, and devals (deviation from axial linearity) mark the separation of individual clusters of distinct isotopic composition and trace element ratios that indicate source variations. This correlated chemical clustering and morphological segmentation indicates that source composition and segmentation can be closely related even on a fine scale. Substantial chemical variations within a segment are related to source composition. This suggests that even within segments the magma transport is mainly vertical, and there is limited along‐ridge transport, and there is little evidence for magma chambers that are well mixed along strike. Trace element concentrations show good correlations with isotopic compositions on a segment scale but less so on a regional scale. The trace element and isotopic variability along the northern East Pacific Rise can be explained by three mantle components: a depleted peridotite endmember, an enriched peridotite endmember, and a recycled gabbro‐like component. The gabbroic component has an isotopic signature indicating an ancient origin. The high‐resolution sampling indicates that within a segment the chemical variability is largely binary but that the endmembers of the binary mixing change from segment to segment. The endmembers of the binary variation within a segment are a combination of three of the endmembers. 

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2. Accelerating Video Segment Access via Quality-Aware Multi-Source Selection

   https://doi.org/10.1145/3712676.3714449  

   Winecki, Dominik; Nandi, Arnab (March 2025, ACM)

   Video data can be slow to process due to the size of video streams and the computational complexity needed to decode, transform, and encode them. These challenges are particularly significant in interactive applications, such as quickly generating compilation videos from a user search. We look at optimizing access to source video segments in multimedia systems where multiple separately encoded copies of video sources are available, such as proxy/optimized media in conventional non-linear video editors or VOD streams in content distribution networks. Rather than selecting a single source to use (e.g., "use the lowest-bitrate 720p source"), we specify a minimum visual quality (e.g., "use any frames with VMAF ≥ 85"). This quality constraint and the needed segment bounds are used to find the lowest-latency operations to decode a segment from multiple available sources with diverse bitrates, resolutions, and codecs. This uses higher-quality/slower-to-decode sources if the encoding is better aligned for the specific segment bounds, which can provide faster access than using just one lower-quality source. We provide a general solution to this Quality-Aware Multi-Source Selection problem with optimal computational complexity. We create a dataset using adaptive-bitrate streaming Video on Demand sources from YouTube's CDN. We evaluate our algorithm on simple segment decoding as well as embedded into a larger editing system---a declarative video editor. Our evaluation shows up to 23% lower latency access, depending on segment length, at identical visual quality levels. 

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3. Multiscale architecture for fast optical addressing and control of large-scale qubit arrays

   https://doi.org/10.1364/AO.484367  

   Graham, T_M; Oh, E.; Saffman, M. (April 2023, Applied Optics)

   This paper presents a technique for rapid site-selective control of the quantum state of particles in a large array using the combination of a fast deflector (e.g., an acousto-optic deflector) and a relatively slow spatial light modulator (SLM). The use of SLMs for site-selective quantum state manipulation has been limited due to slow transition times that prevent rapid, consecutive quantum gates. By partitioning the SLM into multiple segments and using a fast deflector to transition between them, it is possible to substantially reduce the average time increment between scanner transitions by increasing the number of gates that can be performed for a single SLM full-frame setting. We analyzed the performance of this device in two different configurations: In configuration 1, each SLM segment addresses the full qubit array; in configuration 2, each SLM segment addresses a subarray and an additional fast deflector positions that subarray with respect to the full qubit array. With these hybrid scanners, we calculated qubit addressing rates that are tens to hundreds of times faster than using an SLM alone. 

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4. Rate of homogenization for fully-coupled McKean–Vlasov SDEs

   https://doi.org/10.1142/S0219493723500132  

   Bezemek, Zachary William; Spiliopoulos, Konstantinos (January 2023, Stochastics and Dynamics)

   In this paper, we consider a fully-coupled slow–fast system of McKean–Vlasov stochastic differential equations with full dependence on the slow and fast component and on the law of the slow component and derive convergence rates to its homogenized limit. We do not make periodicity assumptions, but we impose conditions on the fast motion to guarantee ergodicity. In the course of the proof we obtain related ergodic theorems and we gain results on the regularity of Poisson type of equations and of the associated Cauchy problem on the Wasserstein space that are of independent interest. 

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5. Excitation of San Andreas tremors by thermal instabilities below the seismogenic zone

   https://doi.org/10.1126/sciadv.abb2057  

   Wang, Lifeng; Barbot, Sylvain (September 2020, Science Advances)

   null (Ed.)

   The relative motion of tectonic plates is accommodated at boundary faults through slow and fast ruptures that encompass a wide range of source properties. Near the Parkfield segment of the San Andreas fault, low-frequency earthquakes and slow-slip events take place deeper than most seismicity, at temperature conditions typically associated with stable sliding. However, laboratory experiments indicate that the strength of granitic gouge decreases with increasing temperature above 350°C, providing a possible mechanism for weakening if temperature is to vary dynamically. Here, we argue that recurring low-frequency earthquakes and slow-slip transients at these depths may arise because of shear heating and the temperature dependence of frictional resistance. Recurring thermal instabilities can explain the recurrence pattern of the mid-crustal low-frequency earthquakes and their correlative slip distribution. Shear heating associated with slow slip is sufficient to generate pseudotachylyte veins in host rocks even when fault slip is dominantly aseismic. 

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