2,178 research outputs found
SSAH: Semi-supervised Adversarial Deep Hashing with Self-paced Hard Sample Generation
Deep hashing methods have been proved to be effective and efficient for
large-scale Web media search. The success of these data-driven methods largely
depends on collecting sufficient labeled data, which is usually a crucial
limitation in practical cases. The current solutions to this issue utilize
Generative Adversarial Network (GAN) to augment data in semi-supervised
learning. However, existing GAN-based methods treat image generations and
hashing learning as two isolated processes, leading to generation
ineffectiveness. Besides, most works fail to exploit the semantic information
in unlabeled data. In this paper, we propose a novel Semi-supervised Self-pace
Adversarial Hashing method, named SSAH to solve the above problems in a unified
framework. The SSAH method consists of an adversarial network (A-Net) and a
hashing network (H-Net). To improve the quality of generative images, first,
the A-Net learns hard samples with multi-scale occlusions and multi-angle
rotated deformations which compete against the learning of accurate hashing
codes. Second, we design a novel self-paced hard generation policy to gradually
increase the hashing difficulty of generated samples. To make use of the
semantic information in unlabeled ones, we propose a semi-supervised consistent
loss. The experimental results show that our method can significantly improve
state-of-the-art models on both the widely-used hashing datasets and
fine-grained datasets
A cytoplasmic Cu-Zn superoxide dismutase SOD1 contributes to hyphal growth and virulence of Fusarium graminearum
AbstractSuperoxide dismutases (SODs) are scavengers of superoxide radicals, one of the main reactive oxygen species (ROS) in the cell. SOD-based ROS scavenging system constitutes the frontline defense against intra- and extracellular ROS, but the roles of SODs in the important cereal pathogen Fusarium graminearum are not very clear. There are five SOD genes in F. graminearum genome, encoding cytoplasmic Cu-Zn SOD1 and MnSOD3, mitochondrial MnSOD2 and FeSOD4, and extracellular CuSOD5. Previous studies reported that the expression of SOD1 increased during infection of wheat coleoptiles and florets. In this work we showed that the recombinant SOD1 protein had the superoxide dismutase activity in vitro, and that the SOD1-mRFP fusion protein localized in the cytoplasm of F. graminearum. The Δsod1 mutants had slightly reduced hyphal growth and markedly increased sensitivity to the intracellular ROS generator menadione. The conidial germination under extracellular oxidative stress was significantly delayed in the mutants. Wheat floret infection assay showed that the Δsod1 mutants had a reduced pathogenicity. Furthermore, the Δsod1 mutants had a significant reduction in production of deoxynivalenol mycotoxin. Our results indicate that the cytoplasmic Cu-Zn SOD1 affects fungal growth probably depending on detoxification of intracellular superoxide radicals, and that SOD1-mediated deoxynivalenol production contributes to the virulence of F. graminearum in wheat head infection
5-Amino-7-(3-chlorophenyl)-3,7-dihydro-2H-thieno[3,2-b]pyran-6-carbonitrile 1,1-dioxide
The title compound, C14H11ClN2O3S, with fused thiophene and pyran rings, was synthesized via the condensation of dihydrothiophen-3(2H)-one 1,1-dioxide and 2-(3-chlorobenzylidene)malononitrile catalysed by triethylamine in ethanol. The thiophene ring adopts an envelope conformation and the pyran ring is planar (r.m.s. deviation = 0.0067 Å). The dihedral angle between the pyran and phenyl rings is 80.8 (1)°. The crystal packing is stabilized by intermolecular N—H⋯N and N—H⋯O hydrogen bonds in which the cyano N and sulphone O atoms, respectively, acting as acceptors
Ethyl 7-(4-bromophenyl)-5-trifluoromethyl-4,7-dihydrotetrazolo[1,5-a]pyrimidine-6-carboxylate
In the title compound, C14H11BrF3N5O2, the pyrimidine ring adopts a flattened envelope conformation with sp
3-hybridized carbon as the flap [deviation = 0.177 (3) Å]. The dihedral angle between tetrazole and bromophenyl rings is 84.3 (1)°. In the crystal, molecules are linked into centrosymmetric dimers by pairs of N—H⋯N hydrogen bonds
5′-Amino-2-oxo-2′,3′-dihydrospiro[indoline-3,7′-thieno[3,2-b]pyran]-6′-carbonitrile 1′,1′-dioxide
In the title compound, C15H11N3O4S, the dihedral angle between the mean planes of the dihydroindol-2-one (r.m.s. deviation = 0.015 Å) and dihydrothieno[3,2-b]pyran (r.m.s. deviation = 0.011 Å) ring systems is 89.53 (3)°. The crytal packing is consolidated by intermolecular N—H⋯O and N—H⋯N hydrogen bonds, which link the molecules into a two-dimensional network into sheets lying parallel to (100)
Hierarchical Graph Pattern Understanding for Zero-Shot VOS
The optical flow guidance strategy is ideal for obtaining motion information
of objects in the video. It is widely utilized in video segmentation tasks.
However, existing optical flow-based methods have a significant dependency on
optical flow, which results in poor performance when the optical flow
estimation fails for a particular scene. The temporal consistency provided by
the optical flow could be effectively supplemented by modeling in a structural
form. This paper proposes a new hierarchical graph neural network (GNN)
architecture, dubbed hierarchical graph pattern understanding (HGPU), for
zero-shot video object segmentation (ZS-VOS). Inspired by the strong ability of
GNNs in capturing structural relations, HGPU innovatively leverages motion cues
(\ie, optical flow) to enhance the high-order representations from the
neighbors of target frames. Specifically, a hierarchical graph pattern encoder
with message aggregation is introduced to acquire different levels of motion
and appearance features in a sequential manner. Furthermore, a decoder is
designed for hierarchically parsing and understanding the transformed
multi-modal contexts to achieve more accurate and robust results. HGPU achieves
state-of-the-art performance on four publicly available benchmarks (DAVIS-16,
YouTube-Objects, Long-Videos and DAVIS-17). Code and pre-trained model can be
found at \url{https://github.com/NUST-Machine-Intelligence-Laboratory/HGPU}.Comment: accepted by IEEE Transactions on Image Processin
5-Amino-7-(4-bromophenyl)-3,7-dihydro-2H-thieno[3,2-b]pyran-6-carbonitrile 1,1-dioxide
In the title compound, C14H11BrN2O3S, the 2,3-dihydrothiophene ring is almost planar [maximum deviation = 0.006 (1) Å]. The pyran ring is in an envelope conformation [puckering parameters Q = 0.115 (2) Å, θ = 77.5 (10), ϕ = 172.9 (10)°]. The pyran and phenyl rings are approximately perpendicular, making a dihedral angle of −76.4 (2)°. The crystal packing is stabilized by intermolecular N—H⋯O hydrogen bonds, with the sulfone O atoms acting as acceptors
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