Does elevated pulse wave velocity improve risk prediction in low-risk populations?
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High-throughput numerical modeling of the tunable synaptic behavior in 2D MoS2 memristive devices
Memristive devices based on two-dimensional (2D) materials have emerged as potential synaptic candidates for next-generation neuromorphic computing hardware. Here, we introduce a numerical modeling framework that facilitates efficient exploration of the large parameter space for 2D memristive synaptic devices. High-throughput charge-transport simulations are performed to investigate the voltage pulse characteristics for lateral 2D memristors and synaptic device metrics are studied for different weight-update schemes. We show that the same switching mechanism can lead to fundamentally different pulse characteristics influencing not only the device metrics but also the weight-update direction. A thorough analysis of the parameter space allows simultaneous optimization of the linearity, symmetry, and drift in the synaptic behavior that are related through tradeoffs. The presented modeling framework can serve as a tool for designing 2D memristive devices in practical neuromorphic circuits by providing guidelines for materials properties, device functionality, and system performance for target applications.
Advancements in ultrafast photonics: confluence of nonlinear optics and intelligent strategies
Automatic mode-locking techniques, the integration of intelligent technologies with nonlinear optics offers the promise of on-demand intelligent control, potentially overcoming the inherent limitations of traditional ultrafast pulse generation that have predominantly suffered from the instability and suboptimality of open-loop manual tuning. The advancements in intelligent algorithm-driven automatic mode-locking techniques primarily are explored in this review, which also revisits the fundamental principles of nonlinear optical absorption, and examines the evolution and categorization of conventional mode-locking techniques. The convergence of ultrafast pulse nonlinear interactions with intelligent technologies has intricately expanded the scope of ultrafast photonics, unveiling considerable potential for innovation and catalyzing new waves of research breakthroughs in ultrafast photonics and nonlinear optics characters.
Rapid evolution of energetic lightning strokes in Mediterranean winter storms
The occurrence of winter lightning concentrates in a few specific regions in the world, including the Mediterranean, where electromagnetic signatures of this interesting dangerous phenomenon have not yet been studied in detail. We investigate the initial stage of energetic negative cloud-to-ground winter lightning flashes in the West Mediterranean region using broadband magnetic field measurements (5 kHz–90 MHz) recorded in winter 2014/2015, which was unusually rich in global lightning activity. We found that the winter pre-stroke processes leading to the high peak current lightning (<−100 kA) lasted on average only 1.7 ms (in one case only 220 µs). Rapid evolution of energetic lightning indicates that leader initiation charge centers can be as low as 500 m above the ground. The measured distribution of pre-stroke pulse amplitudes and interpulse intervals can be used to model the charge structure in the lower thundercloud dipole and to derive the properties of in-cloud lightning channels.
Tailoring microbial redox with alternating current for efficient mineralization of refractory organic nitrogen compounds in wastewater
Traditional biological wastewater treatment struggles to efficiently remove refractory organic nitrogen compounds (RONCs). This study demonstrates the potential of alternating current (AC)-driven bioelectrodes for deep mineralization of nitrobenzene (NB) by coupling in situ reduction and oxidation reactions. Sine-wave AC bioelectrodes overcome the limitations of direct current (DC) systems, achieving 97.6% NB reduction, 90.9% intermediate mineralization, and 80.8% total nitrogen removal while reducing energy consumption by 22.3%. AC stimulation enhances biofilm formation and bidirectional electrocatalytic activity, leading to higher biomass and electron utilization efficiency. Multi-omics analysis shows enrichment of functional microbial consortia involved in NB reduction, aromatic compound oxidation, ammonia oxidation, nitrate/nitrite reduction, and electron transfer, with upregulated enzyme gene expression. Carbon metabolites from catechol meta-cleavage support nitro-reduction, denitrification, and cell viability without external carbon sources. Nitrification-denitrification is the primary pathway for inorganic nitrogen removal. This AC bioelectrode offers an efficient, low-carbon solution for RONC mineralization in wastewater.
Dynamic configuration before quasi-biennial oscillation disruptions revealed from the perspective of planetary waves
The zonal wind in the tropical stratosphere shows a quasi-biennial oscillation (QBO), which is an important reference for climate prediction and stratosphere-troposphere interaction. However, the periodicity of the QBO was disrupted during the 2015/16 and 2019/20 Northern Hemisphere winters, raising big challenges to its predictability and attracting widespread attention. Previous studies have indicated that planetary wave (PW) activity from mid-latitude in the lower stratosphere is one of the main sources for the reversal of the zonal wind field, our results show that in addition to that, the presence of dissipated eastward-moving waves in the middle stratosphere can be important for the formation of QBO disruptions. The above two wave signs appear successively before the disruption, exert strong negative forcing on the background flow, and together form a dynamic configuration that occurs before the tropical stratospheric circulation anomalies. It may be necessary to take this PW dynamic configuration into account when predicting future QBO disruptions.
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