156 research outputs found

    Investigation of Effects of Strouhal and Reynolds numbers on Propulsive Efficiency of Plunging and Pitching Foils

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    The 11th International Symposium on Adaptive Motion of Animals and Machines. Kobe University, Japan. 2023-06-06/09. Adaptive Motion of Animals and Machines Organizing Committee.Poster Session P2

    Formation of an SIR-Nucleosome Filament in vitro and Its Modulation by O-Acetyl-ADP-Ribose

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    It is not possible to clearly visualize how chromatin condenses to heterochromatin in vivo. However, in an in vitro system for Saccharomyces cerevisiae, the requirements for heterochromatin filament formation mirror those found in vivo. Here we report that the nucleosomes and the Sir2, Sir3 and Sir4 proteins, which are required for in vitro filament assembly, are also components of these filaments, confirming that the filaments are SIR-nucleosome filaments. We show the individual localization patterns of the Sir proteins on this SIR-nucleosome filament, and demonstrate that the metabolite, AAR, plays a specific and essential role in promoting the formation of this SIR-nucleosome filament

    A modeling study of the nonlinear response of fine particles to air pollutant emissions in the Beijing-Tianjin-Hebei region

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    The Beijing–Tianjin–Hebei (BTH) region has been suffering from the most severe fine-particle (PM2:5) pollution in China, which causes serious health damage and economic loss. Quantifying the source contributions to PM2:5 concentrations has been a challenging task because of the complicated nonlinear relationships between PM2:5 concentrations and emissions of multiple pollutants from multiple spatial regions and economic sectors. In this study, we use the extended response surface modeling (ERSM) technique to investigate the nonlinear response of PM2:5 concentrations to emissions of multiple pollutants from different regions and sectors over the BTH region, based on over 1000 simulations by a chemical transport model (CTM). The ERSM-predicted PM2:5 concentrations agree well with independent CTM simulations, with correlation coefficients larger than 0.99 and mean normalized errors less than 1 %. Using the ERSM technique, we find that, among all air pollutants, primary inorganic PM2:5 makes the largest contribution (24–36 %) to PM2:5 concentrations. The contribution of primary inorganic PM2:5 emissions is especially high in heavily polluted winter and is dominated by the industry as well as residential and commercial sectors, which should be prioritized in PM2:5 control strategies. The total contributions of all precursors (nitrogen oxides, NOx ; sulfur dioxides, SO2; ammonia, NH3; non-methane volatile organic compounds, NMVOCs; intermediate-volatility organic compounds, IVOCs; primary organic aerosol, POA) to PM2:5 concentrations range between 31 and 48 %. Among these precursors, PM2:5 concentrations are primarily sensitive to the emissions of NH3, NMVOCCIVOC, and POA. The sensitivities increase substantially for NH3 and NOx and decrease slightly for POA and NMVOCCIVOC with the increase in the emission reduction ratio, which illustrates the nonlinear relationships between precursor emissions and PM2:5 concentrations. The contributions of primary inorganic PM2:5 emissions to PM2:5 concentrations are dominated by local emission sources, which account for over 75% of the total primary inorganic PM2:5 contributions. For precursors, however, emissions from other regions could play similar roles to local emission sources in the summer and over the northern part of BTH. The source contribution features for various types of heavy-pollution episodes are distinctly different from each other and from the monthly mean results, illustrating that control strategies should be differentiated based on the major contributing sources during different types of episodes.publishedVersio

    Fault Tolerant Nanosatellite Computing on a Budget

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    In this contribution, we present a CubeSat-compatible on-board computer (OBC) architecture that offers strong fault tolerance to enable the use of such spacecraft in critical and long-term missions. We describe in detail the design of our OBC’s breadboard setup, and document its composition from the component-level, all the way down to the software level. Fault tolerance in this OBC is achieved without resorting to radiation hardening, just intelligent through software. The OBC ages graceful, and makes use of FPGA-reconfiguration and mixed criticality. It can dynamically adapt to changing performance requirements throughout a space mission. We developed a proof-of-concept with several Xilinx Ultrascale and Ultrascale+ FPGAs. With the smallest Kintex Ultrascale+ KU3P device, we achieve 1.94W total power consumption at 300Mhz, well within the power budget range of current 2U CubeSats. To our knowledge, this is the first scalable and COTS-based, widely reproducible OBC solution which can offer strong fault coverage even for small CubeSats. To reproduce this OBC architecture, no custom-written, proprietary, or protected IP is needed, and the needed design tools are available free-of-charge to academics. All COTS components required to construct this architecture can be purchased on the open market, and are affordable even for academic and scientific CubeSat developers

    VoiceBank-2023: A Multi-Speaker Mandarin Speech Corpus for Constructing Personalized TTS Systems for the Speech Impaired

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    Services of personalized TTS systems for the Mandarin-speaking speech impaired are rarely mentioned. Taiwan started the VoiceBanking project in 2020, aiming to build a complete set of services to deliver personalized Mandarin TTS systems to amyotrophic lateral sclerosis patients. This paper reports the corpus design, corpus recording, data purging and correction for the corpus, and evaluations of the developed personalized TTS systems, for the VoiceBanking project. The developed corpus is named after the VoiceBank-2023 speech corpus because of its release year. The corpus contains 29.78 hours of utterances with prompts of short paragraphs and common phrases spoken by 111 native Mandarin speakers. The corpus is labeled with information about gender, degree of speech impairment, types of users, transcription, SNRs, and speaking rates. The VoiceBank-2023 is available by request for non-commercial use and welcomes all parties to join the VoiceBanking project to improve the services for the speech impaired.Comment: submitted to 26th International Conference of the ORIENTAL-COCOSD

    Identification of Antifreeze Proteins and Their Functional Residues by Support Vector Machine and Genetic Algorithms based on n-Peptide Compositions

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    For the first time, multiple sets of n-peptide compositions from antifreeze protein (AFP) sequences of various cold-adapted fish and insects were analyzed using support vector machine and genetic algorithms. The identification of AFPs is difficult because they exist as evolutionarily divergent types, and because their sequences and structures are present in limited numbers in currently available databases. Our results reveal that it is feasible to identify the shared sequential features among the various structural types of AFPs. Moreover, we were able to identify residues involved in ice binding without requiring knowledge of the three-dimensional structures of these AFPs. This approach should be useful for genomic and proteomic studies involving cold-adapted organisms

    Change in household fuels dominates the decrease in PM_(2.5) exposure and premature mortality in China in 2005–2015

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    To tackle the severe fine particle (PM_(2.5)) pollution in China, the government has implemented stringent control policies mainly on power plants, industry, and transportation since 2005, but estimates of the effectiveness of the policy and the temporal trends in health impacts are subject to large uncertainties. By adopting an integrated approach that combines chemical transport simulation, ambient/household exposure evaluation, and health-impact assessment, we find that the integrated population-weighted exposure to PM_(2.5) (IPWE) decreased by 47% (95% confidence interval, 37–55%) from 2005 [180 (146–219) μg/m^3] to 2015 [96 (83–111) μg/m^3]. Unexpectedly, 90% (86–93%) of such reduction is attributed to reduced household solid-fuel use, primarily resulting from rapid urbanization and improved incomes rather than specific control policies. The IPWE due to household fuels for both cooking and heating decreased, but the impact of cooking is significantly larger. The reduced household-related IPWE is estimated to avoid 0.40 (0.25–0.57) million premature deaths annually, accounting for 33% of the PM_(2.5)-induced mortality in 2015. The IPWE would be further reduced by 63% (57–68%) if the remaining household solid fuels were replaced by clean fuels, which would avoid an additional 0.51 (0.40–0.64) million premature deaths. Such a transition to clean fuels, especially for heating, requires technology innovation and policy support to overcome the barriers of high cost of distribution systems, as is recently being attempted in the Beijing–Tianjin–Hebei area. We suggest that household-fuel use be more highly prioritized in national control policies, considering its effects on PM_(2.5) exposures

    Split-spectrum amplitude-decorrelation angiography with optical coherence tomography

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    Amplitude decorrelation measurement is sensitive to transverse flow and immune to phase noise in comparison to Doppler and other phase-based approaches. However, the high axial resolution of OCT makes it very sensitive to the pulsatile bulk motion noise in the axial direction. To overcome this limitation, we developed split-spectrum amplitude-decorrelation angiography (SSADA) to improve the signal-to-noise ratio (SNR) of flow detection. The full OCT spectrum was split into several narrower bands. Inter-B-scan decorrelation was computed using the spectral bands separately and then averaged. The SSADA algorithm was tested on in vivo images of the human macula and optic nerve head. It significantly improved both SNR for flow detection and connectivity of microvascular network when compared to other amplitude-decorrelation algorithms.National Institutes of Health (U.S.) (Grant R01 EY013516)National Institutes of Health (U.S.) (Grant R01-EY11289-26)United States. Air Force Office of Scientific Research (FA9550-10-1-0551

    Neoproterozoic to Paleozoic long-lived accretionary orogeny in the northern Tarim Craton

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    The Tarim Craton, located in the center of Asia, was involved in the assembly and breakup of the Rodinia supercontinent during the Neoproterozoic and the subduction-accretion of the Central Asian Orogenic Belt (CAOB) during the Paleozoic. However, its tectonic evolution during these events is controversial, and a link between the Neoproterozoic and Paleozoic tectonic processes is missing. Here we present zircon U-Pb ages, Hf isotopes, and whole-rock geochemical data for the extensive granitoids in the western Kuruktag area, northeastern Tarim Craton. Three distinct periods of granitoid magmatism are evident: circa 830–820 Ma, 660–630 Ma, and 420–400 Ma. The magma sources, melting conditions (pressure, temperature, and water availability), and tectonic settings of various granitoids from each period are determined. Based on our results and the geological, geochronological, geochemical, and isotopic data from adjacent areas, a long-lived accretionary orogenic model is proposed. This model involves an early phase (circa 950–780 Ma) of southward advancing accretion from the Tianshan to northern Tarim and a late phase (circa 780–600 Ma) of northward retreating accretion, followed by back-arc opening and subsequent bidirectional subduction (circa 460–400 Ma) of a composite back-arc basin (i.e., the South Tianshan Ocean). Our model highlights a long-lived accretionary history of the southwestern CAOB, which may have initiated as part of the circum-Rodinia subduction zone and was comparable with events occurring at the southern margin of the Siberian Craton, thus challenging the traditional southward migrating accretionary models for the CAOB
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