564 research outputs found
Improving the Effective Potential, Multi-Mass Problem and Modified Mass-Dependent Scheme
We present a new procedure for improving the effective potential by using
renormalization group equation (RGE) in the presence of several mass scales. We
propose a modification of the mass-dependent (MD) renormalization scheme, MDbar
scheme, so that the scalar mass parameter runs at most logarithmically on the
one hand and the decoupling of heavy particles is naturally incorporated in the
RGE's on the other. Thanks to these properties, the procedure in MDbar scheme
turns out to be very simple compared with the regionwise procedure in MSbar
scheme proposed previously. The relation with other schemes is also discussed
both analytically and numerically.Comment: 34 pages, 9 Post-Script figures are include
Brain-mediated Transfer Learning of Convolutional Neural Networks
The human brain can effectively learn a new task from a small number of
samples, which indicate that the brain can transfer its prior knowledge to
solve tasks in different domains. This function is analogous to transfer
learning (TL) in the field of machine learning. TL uses a well-trained feature
space in a specific task domain to improve performance in new tasks with
insufficient training data. TL with rich feature representations, such as
features of convolutional neural networks (CNNs), shows high generalization
ability across different task domains. However, such TL is still insufficient
in making machine learning attain generalization ability comparable to that of
the human brain. To examine if the internal representation of the brain could
be used to achieve more efficient TL, we introduce a method for TL mediated by
human brains. Our method transforms feature representations of audiovisual
inputs in CNNs into those in activation patterns of individual brains via their
association learned ahead using measured brain responses. Then, to estimate
labels reflecting human cognition and behavior induced by the audiovisual
inputs, the transformed representations are used for TL. We demonstrate that
our brain-mediated TL (BTL) shows higher performance in the label estimation
than the standard TL. In addition, we illustrate that the estimations mediated
by different brains vary from brain to brain, and the variability reflects the
individual variability in perception. Thus, our BTL provides a framework to
improve the generalization ability of machine-learning feature representations
and enable machine learning to estimate human-like cognition and behavior,
including individual variability
A new species of Cybaeus with short genitalia from central Honshu, Japan (Araneae: Cybaeidae)
Spiders of the genus Cybaeus are diverse in Japan and exhibit extensive morphological variation of their genitalia among species. Among Japanese Cybaeus, several species possess an elongated embolus in males and elongated spermathecae in females. Here, we describe Cybaeus iharai sp. nov. from Nagano Prefecture, central Honshu, Japan, which possesses a short embolus in males and short copulatory ducts in females. In addition, DNA sequences of the new species were obtained for future phylogenetic analyses
The subterranean spider Cybaeus fujisanus (Araneae: Cybaeidae) revisited: the first description of a male from Mt. Fuji, Japan
A taxonomic account of the spider Cybaeus fujisanus Yaginuma, 1972, which was described on the basis of only a female holotype from a cave at the foot of Mt. Fuji, Japan, is revisited. A male specimen was collected near the type locality and is described for the first time. A redescription of the female using the holotype and other newly collected specimens is also provided. The conspecificity of the present male and female specimens was confirmed using nuclear ITS-1 and mitochondrial COI sequences
A new species of Cybaeus L. Koch, 1868 (Araneae, Cybaeidae) with simple genitalia from central Japan is the sister species of C. melanoparvus Kobayashi, 2006 with elongated genitalia
Spiders of the genus Cybaeus L. Koch, 1868 exhibit two major centers of diversity: Western North America and Japan. Several Japanese Cybaeus possess an elongated embolus in the male palp and elongated tubular spermathecae in the female genitalia. Here we describe Cybaeus koikei sp. nov. from central Honshu, Japan, which has an unelongated embolus and bulbous spermathecae. Phylogenetic analyses using nuclear and mitochondrial gene markers clearly support the monophyly of C. koikei sp. nov. and Cybaeus melanoparvus Kobayashi, 2006, a species with elongated genitalia. Both species share a similar habitus and a cluster of robust setae on the lateral surface of the male palpal patella. The latter is considered a synapomorphy for C. koikei sp. nov. and C. melanoparvus. A supplementary description of the spermathecae of C. melanoparvus is also provided
Long-Read-Resolved, Ecosystem-Wide Exploration of Nucleotide and Structural Microdiversity of Lake Bacterioplankton Genomes
環境微生物のゲノム多様性を高解像度に検出 --「似て非なるゲノム」から生物多様性の源泉に迫る--. 京都大学プレスリリース. 2022-08-10.Same same but different. 京都大学プレスリリース. 2022-09-22.Reconstruction of metagenome-assembled genomes (MAGs) has become a fundamental approach in microbial ecology. However, a MAG is hardly complete and overlooks genomic microdiversity because metagenomic assembly fails to resolve microvariants among closely related genotypes. Aiming at understanding the universal factors that drive or constrain prokaryotic genome diversification, we performed an ecosystem-wide high-resolution metagenomic exploration of microdiversity by combining spatiotemporal (2 depths × 12 months) sampling from a pelagic freshwater system, high-quality MAG reconstruction using long- and short-read metagenomic sequences, and profiling of single nucleotide variants (SNVs) and structural variants (SVs) through mapping of short and long reads to the MAGs, respectively. We reconstructed 575 MAGs, including 29 circular assemblies, providing high-quality reference genomes of freshwater bacterioplankton. Read mapping against these MAGs identified 100 to 101, 781 SNVs/Mb and 0 to 305 insertions, 0 to 467 deletions, 0 to 41 duplications, and 0 to 6 inversions for each MAG. Nonsynonymous SNVs were accumulated in genes potentially involved in cell surface structural modification to evade phage recognition. Most (80.2%) deletions overlapped with a gene coding region, and genes of prokaryotic defense systems were most frequently (>8% of the genes) overlapped with a deletion. Some such deletions exhibited a monthly shift in their allele frequency, suggesting a rapid turnover of genotypes in response to phage predation. MAGs with extremely low microdiversity were either rare or opportunistic bloomers, suggesting that population persistency is key to their genomic diversification. The results concluded that prokaryotic genomic diversification is driven primarily by viral load and constrained by a population bottleneck
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