8,868 research outputs found
Holographic entanglement of purification for thermofield double states and thermal quench
We explore the properties of holographic entanglement of purification (EoP)
for two disjoint strips in the Schwarzschild-AdS black brane and the Vaidya-AdS
black brane spacetimes. For two given strips on the same boundary of
Schwarzschild-AdS spacetime, there is an upper bound of the separation beyond
which the holographic EoP will always vanish no matter how wide the strips are.
In the case that two strips are in the two boundaries of the spacetime
respectively, we find that the holographic EoP exists only when the strips are
wide enough. If the width is finite, the EoP can be nonzero in a finite time
region. For thermal quench case, we find that the equilibrium time of
holographic EoP is only sensitive to the width of strips, while that of the
holographic mutual information is sensitive not only to the width of strips but
also to their separation.Comment: 23 pages, 12 figures, major correction of section
Res2Net: A New Multi-scale Backbone Architecture
Representing features at multiple scales is of great importance for numerous
vision tasks. Recent advances in backbone convolutional neural networks (CNNs)
continually demonstrate stronger multi-scale representation ability, leading to
consistent performance gains on a wide range of applications. However, most
existing methods represent the multi-scale features in a layer-wise manner. In
this paper, we propose a novel building block for CNNs, namely Res2Net, by
constructing hierarchical residual-like connections within one single residual
block. The Res2Net represents multi-scale features at a granular level and
increases the range of receptive fields for each network layer. The proposed
Res2Net block can be plugged into the state-of-the-art backbone CNN models,
e.g., ResNet, ResNeXt, and DLA. We evaluate the Res2Net block on all these
models and demonstrate consistent performance gains over baseline models on
widely-used datasets, e.g., CIFAR-100 and ImageNet. Further ablation studies
and experimental results on representative computer vision tasks, i.e., object
detection, class activation mapping, and salient object detection, further
verify the superiority of the Res2Net over the state-of-the-art baseline
methods. The source code and trained models are available on
https://mmcheng.net/res2net/.Comment: 11 pages, 7 figure
Third-codon transversion rate-based _Nymphaea_ basal angiosperm phylogeny -- concordance with developmental evidence
Flowering plants (angiosperms) appeared on Earth rather suddenly approximately 130 million years ago and underwent a massive expansion in the subsequent 10-12 million years. Current molecular phylogenies have predominantly identified _Amborella_, followed by _Nymphaea_ (water lilies) or _Amborella_ plus _Nymphaea_, in the ANITA clade (_Amborella_, Nymphaeales, Illiciaceae, Trimeniaceae and Austrobaileyaceae) as the earliest angiosperm. However, developmental studies suggest that the earliest angiosperm had a 4-cell/4-nucleus female gametophyte and a diploid endosperm represented by _Nymphaea_, suggesting that _Amborella_, having an 8-cell/9-nucleus female gametophyte and a triploid endosperm, cannot be representative of the basal angiosperm. This evolution-development discordance is possibly caused by erroneous inference based on phylogenetic signals with low neutrality and/or high saturation. Here we show that the 3rd codon transversion (P3Tv), with high neutrality and low saturation, is a robust high-resolution phylogenetic signal for such divergences and that the P3Tv-based land plant phylogeny cautiously identifies _Nymphaea_, followed by _Amborella_, as the most basal among the angiosperm species examined in this study. This P3Tv-based phylogeny contributes insights to the origin of angiosperms with concordance to fossil and stomata development evidence
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The Association between Virus Prevalence and Intercolonial Aggression Levels in the Yellow Crazy Ant, Anoplolepis Gracilipes (Jerdon).
The recent discovery of multiple viruses in ants, along with the widespread infection of their hosts across geographic ranges, provides an excellent opportunity to test whether viral prevalence in the field is associated with the complexity of social interactions in the ant population. In this study, we examined whether the association exists between the field prevalence of a virus and the intercolonial aggression of its ant host, using the yellow crazy ant (Anoplolepis gracilipes) and its natural viral pathogen (TR44839 virus) as a model system. We delimitated the colony boundary and composition of A. gracilipes in a total of 12 study sites in Japan (Okinawa), Taiwan, and Malaysia (Penang), through intercolonial aggression assay. The spatial distribution and prevalence level of the virus was then mapped for each site. The virus occurred at a high prevalence in the surveyed colonies of Okinawa and Taiwan (100% infection rate across all sites), whereas virus prevalence was variable (30%-100%) or none (0%) at the sites in Penang. Coincidentally, colonies in Okinawa and Taiwan displayed a weak intercolonial boundary, as aggression between colonies is generally low or moderate. Contrastingly, sites in Penang were found to harbor a high proportion of mutually aggressive colonies, a pattern potentially indicative of complex colony composition. Our statistical analyses further confirmed the observed correlation, implying that intercolonial interactions likely contribute as one of the effective facilitators of/barriers to virus prevalence in the field population of this ant species
Asymmetrically interacting spreading dynamics on complex layered networks
The spread of disease through a physical-contact network and the spread of
information about the disease on a communication network are two intimately
related dynamical processes. We investigate the asymmetrical interplay between
the two types of spreading dynamics, each occurring on its own layer, by
focusing on the two fundamental quantities underlying any spreading process:
epidemic threshold and the final infection ratio. We find that an epidemic
outbreak on the contact layer can induce an outbreak on the communication
layer, and information spreading can effectively raise the epidemic threshold.
When structural correlation exists between the two layers, the information
threshold remains unchanged but the epidemic threshold can be enhanced, making
the contact layer more resilient to epidemic outbreak. We develop a physical
theory to understand the intricate interplay between the two types of spreading
dynamics.Comment: 29 pages, 14 figure
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