81 research outputs found
On constructibility of AdS supergluon amplitudes
We prove that all tree-level -point supergluon (scalar) amplitudes in
AdS can be recursively constructed, using factorization and flat-space
limit. Our method is greatly facilitated by a natural R-symmetry basis for
planar color-ordered amplitudes, which reduces the latter to "partial
amplitudes" with simpler pole structures and factorization properties. Given
the -point scalar amplitude, we first extract spinning amplitudes with
scalars and one gluon by imposing "gauge invariance", and then use a
special "no-gluon kinematics" to determine the -point scalar amplitude
completely (which in turn contains the -point single-gluon amplitude).
Explicit results of up to 8-point scalar amplitudes and up to 6-point
single-gluon amplitudes are included as supplemental materials.Comment: 5 pages, 4 figures, major revision from v2 including new ancillary
fil
Cutting the traintracks: Cauchy, Schubert and Calabi-Yau
In this note we revisit the maximal-codimension residues, or leading
singularities, of four-dimensional -loop traintrack integrals with massive
legs, both in Feynman parameter space and in momentum (twistor) space. We
identify a class of "half traintracks" as the most general degenerations of
traintracks with conventional (0-form) leading singularities, although the
integrals themselves still have rigidity due to
lower-loop "full traintrack'' subtopologies. As a warm-up exercise, we derive
closed-form expressions for their leading singularities both via (Cauchy's)
residues in Feynman parameters, and more geometrically using the so-called
Schubert problems in momentum twistor space. For -loop full traintracks, we
compute their leading singularities as integrals of -forms, which
proves that the rigidity is as expected; the form is given by an
inverse square root of an irreducible polynomial quartic with respect to each
variable, which characterizes an -dim Calabi-Yau manifold (elliptic
curve, K3 surface, etc.) for any . We also briefly comment on the
implications for the "symbology" of these traintrack integrals.Comment: refs updated; 36 pages, 12 figure
Re-mine, Learn and Reason: Exploring the Cross-modal Semantic Correlations for Language-guided HOI detection
Human-Object Interaction (HOI) detection is a challenging computer vision
task that requires visual models to address the complex interactive
relationship between humans and objects and predict HOI triplets. Despite the
challenges posed by the numerous interaction combinations, they also offer
opportunities for multimodal learning of visual texts. In this paper, we
present a systematic and unified framework (RmLR) that enhances HOI detection
by incorporating structured text knowledge. Firstly, we qualitatively and
quantitatively analyze the loss of interaction information in the two-stage HOI
detector and propose a re-mining strategy to generate more comprehensive visual
representation.Secondly, we design more fine-grained sentence- and word-level
alignment and knowledge transfer strategies to effectively address the
many-to-many matching problem between multiple interactions and multiple
texts.These strategies alleviate the matching confusion problem that arises
when multiple interactions occur simultaneously, thereby improving the
effectiveness of the alignment process. Finally, HOI reasoning by visual
features augmented with textual knowledge substantially improves the
understanding of interactions. Experimental results illustrate the
effectiveness of our approach, where state-of-the-art performance is achieved
on public benchmarks. We further analyze the effects of different components of
our approach to provide insights into its efficacy.Comment: ICCV202
Online human action recognition with spatial and temporal skeleton features using a distributed camera network
Online action recognition is an important task for human-centered intelligent services. However, it remains a highly challenging problem due to the high varieties and uncertainties of spatial and temporal scales of human actions. In this paper, the following core ideas are proposed to deal with the online action recognition problem. First, we combine spatial and temporal skeleton features to represent human actions, which include not only geometrical features, but also multiscale motion features, such that both spatial and temporal information of the actions are covered. We use an efficient one-dimensional convolutional neural network to fuse spatial and temporal features and train them for action recognition. Second, we propose a group sampling method to combine the previous action frames and current action frames, which are based on the hypothesis that the neighboring frames are largely redundant, and the sampling mechanism ensures that the long-term contextual information is also considered. Third, the skeletons from multiview cameras are fused in a distributed manner, which can improve the human pose accuracy in the case of occlusions. Finally, we propose a Restful style based client-server service architecture to deploy the proposed online action recognition module on the remote server as a public service, such that camera networks for online action recognition can benefit from this architecture due to the limited onboard computational resources. We evaluated our model on the data sets of JHMDB and UT-Kinect, which achieved highly promising accuracy levels of 80.1% and 96.9%, respectively. Our online experiments show that our memory group sampling mechanism is far superior to the traditional sliding window
Chromatin interaction neural network (ChINN): a machine learning-based method for predicting chromatin interactions from DNA sequences.
Chromatin interactions play important roles in regulating gene expression. However, the availability of genome-wide chromatin interaction data is limited. We develop a computational method, chromatin interaction neural network (ChINN), to predict chromatin interactions between open chromatin regions using only DNA sequences. ChINN predicts CTCF- and RNA polymerase II-associated and Hi-C chromatin interactions. ChINN shows good across-sample performances and captures various sequence features for chromatin interaction prediction. We apply ChINN to 6 chronic lymphocytic leukemia (CLL) patient samples and a published cohort of 84 CLL open chromatin samples. Our results demonstrate extensive heterogeneity in chromatin interactions among CLL patient samples
Global Changes in Chromatin Accessibility and Transcription in Growth Hormone-Secreting Pituitary Adenoma
PURPOSE: Growth hormone-secreting pituitary adenoma (GHPA) is an insidious disease with persistent hypersecretion of growth hormone and insulin-like growth factor 1, causing increased morbidity and mortality. Previous studies have investigated the transcription of GHPA. However, the gene regulatory landscape has not been fully characterized. The objective of our study was to unravel the changes in chromatin accessibility and transcription in GHPA.
METHODS: Six patients diagnosed with GHPA in the Department of Neurosurgery at Huashan Hospital were enrolled in our study. Primary pituitary adenoma tissues and adjacent normal pituitary specimens with no morphologic abnormalities from these six patients were obtained at surgery. RNA sequencing (RNA-seq) and assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq) were applied to investigate the underlying relationship between gene expression and chromatin accessibility changes in GHPA.
RESULTS: Totally, 1528 differential expression genes (DEGs) were identified by transcriptomics analyses, including 725 up-regulated and 803 down-regulated. Further, we obtained 64 significantly DEGs including 10 DEGs were elevated and 54 DEGs were negligibly expressed in tumors tissues. The up-regulated DEGs were mainly involved in terms related to synapse formation, nervous system development and secretory pathway. In parallel, 3916 increased and 2895 decreased chromatin-accessible regions were mapped by ATAC-seq. Additionally, the chromatin accessible changes were frequently located adjacent to transcription factor CTCF and Rfx2 binding site.
CONCLUSIONS: Our results are the first to demonstrate the landscape of chromatin accessibility in GHPA, which may contribute to illustrate the underlying transcriptional regulation mechanism of this disease
Forty years of reform and opening up:China’s progress toward a sustainable path
After 40 years of reform and “opening up,” China has made remarkable economic progress. Such economic prosperity, however, has been coupled with environmental degradation. We analyze diverse long-term data to determine whether China is experiencing a decoupling of economic growth and environmental impacts, and where China stands with respect to the Sustainable Development Goals (SDGs) in terms of reducing regional division, urban-rural gap, social inequality, and land-based impacts on oceans. The results highlight that China’s desire to achieve “ecological civilization” has resulted in a decoupling trend for major pollutants since 2015, while strong coupling remains with CO2 emissions. Progress has been made in health care provision, poverty reduction, and gender equity in education, while income disparity continues between regions and with rural-urban populations. There is a considerable way to go toward achieving delivery of the SDGs; however, China’s progress toward economic prosperity and concomitant sustainability provides important insights for other countries
Target motion analysis based on peak power measurements using networked sensors
Target motion analysis (TMA) using a network of wireless sensors/receivers which measure the power from a mobile RF emitter is considered. Due to limited communication capability of each sensor node, only peak power measurements from sensor nodes are transmitted to the fusion center. We present two main results that yield the optimum sensors\u27 configuration such that the asymptotically achievable error variance of the target trajectory\u27s estimate is minimized, and we derive efficient numerical algorithms for computing the optimum estimates of the trajectory of the moving target, thus achieving the goal of TMA. © 2011 IEEE
The Core- and Pan-Genomic Analyses of the Genus Comamonas: From Environmental Adaptation to Potential Virulence
Comamonas is often reported to be one of the major members of microbial communities in various natural and engineered environments. Versatile catabolic capabilities of Comamonas have been studied extensively in the last decade. In contrast, little is known about the ecological roles and adaptation of Comamonas to different environments as well as the virulence of potentially pathogenic Comamonas strains. In this study, we provide genomic insights into the potential ecological roles and virulence of Comamonas by analysing the entire gene set (pangenome) and the genes present in all genomes (core genome) using 34 genomes of 11 different Comamonas species. The analyses revealed that the metabolic pathways enabling Comamonas to acquire energy from various nutrient sources are well conserved. Genes for denitrification and ammonification are abundant in Comamonas, suggesting that Comamonas plays an important role in the nitrogen biogeochemical cycle. They also encode sophisticated redox sensory systems and diverse c-di-GMP controlling systems, allowing them to be able to effectively adjust their biofilm lifestyle to changing environments. The virulence factors in Comamonas were found to be highly species-specific. The conserved strategies used by potentially pathogenic Comamonas for surface adherence, motility control, nutrient acquisition and stress tolerance were also revealed.NRF (Natl Research Foundation, S’pore)MOE (Min. of Education, S’pore)Published versio
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