340 research outputs found
Thermodynamics and spin-charge separation of one-dimensional strongly repulsive three-component fermions
The low temperature thermodynamics of one-dimensional strongly repulsive
SU(3) fermions in the presence of a magnetic field is investigated via the
Yang-Yang thermodynamic Bethe ansatz method. The analytical free energy and
magnetic properties of the model at low temperatures in a weak magnetic field
are derived via the Wiener-Hopf method. It is shown that the low energy physics
can be described by spin-charge separated conformal field theories of an
effective Tomonaga-Luttinger liquid and an antiferromagnetic SU(3) Heisenberg
spin chain. Beyond the Tomonaga-Luttinger liquid regime, the equation of state
is given in terms of the polylog function for a weak external field. The
results obtained are essential for further study of quantum criticality in
strongly repulsive three-component fermions.Comment: 21 pages, 2 figure
Incremental Object Detection with CLIP
In the incremental detection task, unlike the incremental classification
task, data ambiguity exists due to the possibility of an image having different
labeled bounding boxes in multiple continuous learning stages. This phenomenon
often impairs the model's ability to learn new classes. However, the forward
compatibility of the model is less considered in existing work, which hinders
the model's suitability for incremental learning. To overcome this obstacle, we
propose to use a language-visual model such as CLIP to generate text feature
embeddings for different class sets, which enhances the feature space globally.
We then employ the broad classes to replace the unavailable novel classes in
the early learning stage to simulate the actual incremental scenario. Finally,
we use the CLIP image encoder to identify potential objects in the proposals,
which are classified into the background by the model. We modify the background
labels of those proposals to known classes and add the boxes to the training
set to alleviate the problem of data ambiguity. We evaluate our approach on
various incremental learning settings on the PASCAL VOC 2007 dataset, and our
approach outperforms state-of-the-art methods, particularly for the new
classes.Comment: 10 pages, 2 figure
OccupancyDETR: Making Semantic Scene Completion as Straightforward as Object Detection
Visual-based 3D semantic occupancy perception (also known as 3D semantic
scene completion) is a new perception paradigm for robotic applications like
autonomous driving. Compared with Bird's Eye View (BEV) perception, it extends
the vertical dimension, significantly enhancing the ability of robots to
understand their surroundings. However, due to this very reason, the
computational demand for current 3D semantic occupancy perception methods
generally surpasses that of BEV perception methods and 2D perception methods.
We propose a novel 3D semantic occupancy perception method, OccupancyDETR,
which consists of a DETR-like object detection module and a 3D occupancy
decoder module. The integration of object detection simplifies our method
structurally - instead of predicting the semantics of each voxels, it
identifies objects in the scene and their respective 3D occupancy grids. This
speeds up our method, reduces required resources, and leverages object
detection algorithm, giving our approach notable performance on small objects.
We demonstrate the effectiveness of our proposed method on the SemanticKITTI
dataset, showcasing an mIoU of 23 and a processing speed of 6 frames per
second, thereby presenting a promising solution for real-time 3D semantic scene
completion
Improved Target-specific Stance Detection on Social Media Platforms by Delving into Conversation Threads
Target-specific stance detection on social media, which aims at classifying a
textual data instance such as a post or a comment into a stance class of a
target issue, has become an emerging opinion mining paradigm of importance. An
example application would be to overcome vaccine hesitancy in combating the
coronavirus pandemic. However, existing stance detection strategies rely merely
on the individual instances which cannot always capture the expressed stance of
a given target. In response, we address a new task called conversational stance
detection which is to infer the stance towards a given target (e.g., COVID-19
vaccination) when given a data instance and its corresponding conversation
thread. To tackle the task, we first propose a benchmarking conversational
stance detection (CSD) dataset with annotations of stances and the structures
of conversation threads among the instances based on six major social media
platforms in Hong Kong. To infer the desired stances from both data instances
and conversation threads, we propose a model called Branch-BERT that
incorporates contextual information in conversation threads. Extensive
experiments on our CSD dataset show that our proposed model outperforms all the
baseline models that do not make use of contextual information. Specifically,
it improves the F1 score by 10.3% compared with the state-of-the-art method in
the SemEval-2016 Task 6 competition. This shows the potential of incorporating
rich contextual information on detecting target-specific stances on social
media platforms and implies a more practical way to construct future stance
detection tasks
Transcriptomic analysis identified SLC40A1 as a key iron metabolism-related gene in airway macrophages in childhood allergic asthma
Introduction: Asthma is the most common chronic condition in children, with allergic asthma being the most common phenotype, accounting for approximately 80% of cases. Growing evidence suggests that disruption of iron homeostasis and iron regulatory molecules may be associated with childhood allergic asthma. However, the underlying molecular mechanism remains unclear.Methods: Three childhood asthma gene expression datasets were analyzed to detect aberrant expression profiles of iron metabolism-related genes in the airways of children with allergic asthma. Common iron metabolism-related differentially expressed genes (DEGs) across the three datasets were identified and were subjected to functional enrichment analysis. Possible correlations between key iron metabolism-related DEGs and type 2 airway inflammatory genes were investigated. Single-cell transcriptome analysis further identified major airway cell subpopulations driving key gene expression. Key iron metabolism-related gene SLC40A1 was validated in bronchoalveolar lavage (BAL) cells from childhood asthmatics with control individuals by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and immunofluorescence. The intracellular iron content in BAL cells was assessed by Perls iron staining and the iron levels in BAL supernatant was measured by iron assay to assess airway iron metabolism status in childhood asthmatics.Results: Five common iron metabolism-related DEGs were identified, which were functionally related to iron homeostasis. Among these genes, downregulated SLC40A1 was strongly correlated with type 2 airway inflammatory markers and the gene signature of SLC40A1 could potentially be used to determine type 2-high and type 2-low subsets in childhood allergic asthmatics. Further single-cell transcriptomic analysis identified airway macrophages driving SLC40A1 expression. Immunofluorescence staining revealed colocalization of FPN (encoded by SLC40A1) and macrophage marker CD68. Down-regulation of SLC40A1 (FPN) was validated by qRT-PCR and immunofluorescence analysis. Results further indicated reduced iron levels in the BAL fluid, but increased iron accumulation in BAL cells in childhood allergic asthma patients. Furthermore, decreased expression of SLC40A1 was closely correlated with reduced iron levels in the airways of children with allergic asthma.Discussion: Overall, these findings reveal the potential role of the iron metabolism-related gene SLC40A1 in the pathogenesis of childhood allergic asthma
Ultrasonic investigation of the Kondo semimetal CeBi
We report the elastic properties of the Kondo semimetal CeBi by resonant
ultrasound spectroscopy measurements at zero magnetic field. Clear elastic
softening is found in bulk modulus below K. Such a softening in
, in addition to the anomalous temperature dependent Poisson's ratio, is
hardly attributable to multipolar response for stable localized orbital,
but can be well described by a two-band model arising from the hybridization
between conduction- and - electrons. These results probably are
consequences of the valence fluctuations in this Kondo semimetal as originally
suggested by a Fermi-surface expansion observed in a previous angle-resolved
photoemission spectroscopy study [P. Li \textit{et al.}, Phys. Rev. B
, 155110 (2019)].Comment: 7+4 pages, 5+2 figures, 2+1 table
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