3,521 research outputs found
MNER-QG: An End-to-End MRC framework for Multimodal Named Entity Recognition with Query Grounding
Multimodal named entity recognition (MNER) is a critical step in information
extraction, which aims to detect entity spans and classify them to
corresponding entity types given a sentence-image pair. Existing methods either
(1) obtain named entities with coarse-grained visual clues from attention
mechanisms, or (2) first detect fine-grained visual regions with toolkits and
then recognize named entities. However, they suffer from improper alignment
between entity types and visual regions or error propagation in the two-stage
manner, which finally imports irrelevant visual information into texts. In this
paper, we propose a novel end-to-end framework named MNER-QG that can
simultaneously perform MRC-based multimodal named entity recognition and query
grounding. Specifically, with the assistance of queries, MNER-QG can provide
prior knowledge of entity types and visual regions, and further enhance
representations of both texts and images. To conduct the query grounding task,
we provide manual annotations and weak supervisions that are obtained via
training a highly flexible visual grounding model with transfer learning. We
conduct extensive experiments on two public MNER datasets, Twitter2015 and
Twitter2017. Experimental results show that MNER-QG outperforms the current
state-of-the-art models on the MNER task, and also improves the query grounding
performance.Comment: 13 pages, 6 figures, published to AAA
Relaxed 2-D Principal Component Analysis by Norm for Face Recognition
A relaxed two dimensional principal component analysis (R2DPCA) approach is
proposed for face recognition. Different to the 2DPCA, 2DPCA- and G2DPCA,
the R2DPCA utilizes the label information (if known) of training samples to
calculate a relaxation vector and presents a weight to each subset of training
data. A new relaxed scatter matrix is defined and the computed projection axes
are able to increase the accuracy of face recognition. The optimal -norms
are selected in a reasonable range. Numerical experiments on practical face
databased indicate that the R2DPCA has high generalization ability and can
achieve a higher recognition rate than state-of-the-art methods.Comment: 19 pages, 11 figure
Early remodeling of the neocortex upon episodic memory encoding
Understanding the mechanisms by which long-term memories are formed and stored in the brain represents a central aim of neuroscience. Prevailing theory suggests that long-term memory encoding involves early plasticity within hippocampal circuits, whereas reorganization of the neocortex is thought to occur weeks to months later to subserve remote memory storage. Here we report that long-term memory encoding can elicit early transcriptional, structural, and functional remodeling of the neocortex. Parallel studies using genome-wide RNA sequencing, ultrastructural imaging, and whole-cell recording in wild-type mice suggest that contextual fear conditioning initiates a transcriptional program in the medial prefrontal cortex (mPFC) that is accompanied by rapid expansion of the synaptic active zone and postsynaptic density, enhanced dendritic spine plasticity, and increased synaptic efficacy. To address the real-time contribution of the mPFC to long-term memory encoding, we performed temporally precise optogenetic inhibition of excitatory mPFC neurons during contextual fear conditioning. Using this approach, we found that real-time inhibition of the mPFC inhibited activation of the entorhinal–hippocampal circuit and impaired the formation of long-term associative memory. These findings suggest that encoding of long-term episodic memory is associated with early remodeling of neocortical circuits, identify the prefrontal cortex as a critical regulator of encoding-induced hippocampal activation and long-term memory formation, and have important implications for understanding memory processing in healthy and diseased brain states.Picower Institute for Learning and Memory (Innovation Fund)Massachusetts Institute of Technology. Department of Brain and Cognitive SciencesBrightFocus Foundation (Research Fellowship A2013026F
A Simple and Low-Cost Strategy to Improve Conidial Yield and Stress Resistance of Trichoderma guizhouense through Optimizing Illumination Conditions
Light is perceived by photoreceptors in fungi and further integrated into the stress-activated MAPK HOG pathway, and thereby potentially activates the expression of genes for stress responses. This indicates that the precise control of light conditions can likely improve the conidial yield and stress resistance to guarantee the low cost and long shelf life of Trichoderma-based biocontrol agents and biofertilizers. In this study, effects of wavelengths and intensities of light on conidial yield and stress tolerance to osmotic, oxidative and pH stresses in Trichoderma guizhouense were investigated. We found that 2 ÎĽmol photons/(m Ă— s) of blue light increased the conidial yield more than 1000 folds as compared to dark condition and simultaneously enhanced conidial stress resistance. The enhanced conidial stress resistance is probably due to the upregulated stress-related genes in blue light, which is under the control of the blue light receptor BLR1 and the MAP kinase HOG1
Visualizing Exotic Orbital Texture in the Single-Layer Mott Insulator 1T-TaSe2
Mott insulating behavior is induced by strong electron correlation and can
lead to exotic states of matter such as unconventional superconductivity and
quantum spin liquids. Recent advances in van der Waals material synthesis
enable the exploration of novel Mott systems in the two-dimensional limit. Here
we report characterization of the local electronic properties of single- and
few-layer 1T-TaSe2 via spatial- and momentum-resolved spectroscopy involving
scanning tunneling microscopy and angle-resolved photoemission. Our combined
experimental and theoretical study indicates that electron correlation induces
a robust Mott insulator state in single-layer 1T-TaSe2 that is accompanied by
novel orbital texture. Inclusion of interlayer coupling weakens the insulating
phase in 1T-TaSe2, as seen by strong reduction of its energy gap and quenching
of its correlation-driven orbital texture in bilayer and trilayer 1T-TaSe2. Our
results establish single-layer 1T-TaSe2 as a useful new platform for
investigating strong correlation physics in two dimensions
Coexistence of ferromagnetism, antiferromagnetism, and superconductivity in magnetically anisotropic (Eu,La)FeAs2
Materials with exceptional magnetism and superconductivity usually conceive
emergent physical phenomena. Here, we investigate the physical properties of
the (Eu,La)FeAs2 system with double magnetic sublattices. The parent EuFeAs2
shows anisotropy-associated magnetic behaviors, such as Eu-related moment
canting and exchange bias. Through La doping, the magnetic anisotropy is
enhanced with ferromagnetism of Eu2+ realized in the overdoped region, and a
special exchange bias of the superposed ferromagnetic/superconducting loop
revealed in Eu0.8La0.2FeAs2. Meanwhile, the Fe-related antiferromagnetism shows
unusual robustness against La doping. Theoretical calculation and 57Fe
M\"ossbauer spectroscopy investigation reveal a doping-tunable dual
itinerant/localized nature of the Fe-related antiferromagnetism. Coexistence of
the Eu-related ferromagnetism, Fe-related robust antiferromagnetism, and
superconductivity is further revealed in Eu0.8La0.2FeAs2, providing a platform
for further exploration of potential applications and emergent physics.
Finally, an electronic phase diagram is established for (Eu,La)FeAs2 with the
whole superconducting dome adjacent to the Fe-related antiferromagnetic phase,
which is of benefit for seeking underlying clues to high-temperature
superconductivity.Comment: 13 pages, 6 figures for the main tex
Distinct roles of NMB and GRP in itch transmission
A key question in our understanding of itch coding mechanisms is whether itch is relayed by dedicated molecular and neuronal pathways. Previous studies suggested that gastrin-releasing peptide (GRP) is an itch-specific neurotransmitter. Neuromedin B (NMB) is a mammalian member of the bombesin family of peptides closely related to GRP, but its role in itch is unclear. Here, we show that itch deficits in mice lacking NMB or GRP are non-redundant and Nmb/Grp double KO (DKO) mice displayed additive deficits. Furthermore, both Nmb/Grp and Nmbr/Grpr DKO mice responded normally to a wide array of noxious stimuli. Ablation of NMBR neurons partially attenuated peripherally induced itch without compromising nociceptive processing. Importantly, electrophysiological studies suggested that GRPR neurons receive glutamatergic input from NMBR neurons. Thus, we propose that NMB and GRP may transmit discrete itch information and NMBR neurons are an integral part of neural circuits for itch in the spinal cord
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