53 research outputs found
Learned spatial data partitioning
Due to the significant increase in the size of spatial data, it is essential
to use distributed parallel processing systems to efficiently analyze spatial
data. In this paper, we first study learned spatial data partitioning, which
effectively assigns groups of big spatial data to computers based on locations
of data by using machine learning techniques. We formalize spatial data
partitioning in the context of reinforcement learning and develop a novel deep
reinforcement learning algorithm. Our learning algorithm leverages features of
spatial data partitioning and prunes ineffective learning processes to find
optimal partitions efficiently. Our experimental study, which uses Apache
Sedona and real-world spatial data, demonstrates that our method efficiently
finds partitions for accelerating distance join queries and reduces the
workload run time by up to 59.4%
Wide-field quantitative magnetic imaging of superconducting vortices using perfectly aligned quantum sensors
Various techniques have been applied to visualize superconducting vortices,
providing clues to their electromagnetic response. Here, we present a
wide-field, quantitative imaging of the stray field of the vortices in a
superconducting thin film using perfectly aligned diamond quantum sensors. Our
analysis, which mitigates the influence of the sensor inhomogeneities,
visualizes the magnetic flux of single vortices in YBaCuO
with an accuracy of . The obtained vortex shape is consistent with
the theoretical model, and penetration depth and its temperature dependence
agree with previous studies, proving our technique's accuracy and broad
applicability. This wide-field imaging, which in principle works even under
extreme conditions, allows the characterization of various superconductors
Ecological Dynamics of Broad- and Narrow-Host-Range Viruses Infecting the Bloom-Forming Toxic Cyanobacterium Microcystis aeruginosa
アオコ感染性広域・狭域宿主ウイルスの動態 --アオコとウイルスはいかに共存するか--. 京都大学プレスリリース. 2023-02-24.Microcystis aeruginosa is predicted to interact and coexist with diverse broad- and narrow-host-range viruses within a bloom; however, little is known about their affects on Microcystis population dynamics. Here, we developed a real-time PCR assay for the quantification of these viruses that have different host ranges. During the sampling period, total Microcystis abundance showed two peaks in May and August with a temporary decrease in June. The Microcystis population is largely divided into three phylotypes based on internal transcribed sequences (ITS; ITS types I to III). ITS I was the dominant phylotype (66% to 88%) except in June. Although the ITS II and III phylotypes were mostly less abundant, these phylotypes temporarily increased to approximately equivalent abundances of the ITS I population in June. During the same sampling period, the abundances of the broad-host-range virus MVGF_NODE331 increased from April to May and from July to October with a temporary decrease in June, in which its dynamics were in proportion to the increase of total Microcystis abundances regardless of changes in host ITS population composition. In contrast, the narrow-host-range viruses MVG_NODE620 and Ma-LMM01 were considerably less abundant than the broad-host-range virus and generally did not fluctuate in the environment. Considering that M. aeruginosa could increase the abundance and sustain the bloom under the prevalence of the broad-host-range virus, host abundant and diverse antiviral mechanisms might contribute to coexistence with its viruses
Virological characteristics of the SARS-CoV-2 Omicron BA.2.75 variant
SARS-CoV-2オミクロンBA.2.75株(通称ケンタウロス)のウイルス学的性状の解明. 京都大学プレスリリース. 2022-10-12.The SARS-CoV-2 Omicron BA.2.75 variant emerged in May 2022. BA.2.75 is a BA.2 descendant but is phylogenetically distinct from BA.5, the currently predominant BA.2 descendant. Here, we show that BA.2.75 has a greater effective reproduction number and different immunogenicity profile than BA.5. We determined the sensitivity of BA.2.75 to vaccinee and convalescent sera as well as a panel of clinically available antiviral drugs and antibodies. Antiviral drugs largely retained potency but antibody sensitivity varied depending on several key BA.2.75-specific substitutions. The BA.2.75 spike exhibited a profoundly higher affinity for its human receptor, ACE2. Additionally, the fusogenicity, growth efficiency in human alveolar epithelial cells, and intrinsic pathogenicity in hamsters of BA.2.75 were greater than those of BA.2. Our multilevel investigations suggest that BA.2.75 acquired virological properties independent of BA.5, and the potential risk of BA.2.75 to global health is greater than that of BA.5
Descriptions of two new silversides, Hypoatherina golanii and Hypoatherina lunata, from the Indo-West Pacific (Atheriniformes: Atherinidae)
Power Reduction of Variable Wordlength OFDM Receiver in Time-Varying Fading Channels by Monitoring Subcarrier SNRs
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