1,739 research outputs found
D2ADA: Dynamic Density-aware Active Domain Adaptation for Semantic Segmentation
In the field of domain adaptation, a trade-off exists between the model
performance and the number of target domain annotations. Active learning,
maximizing model performance with few informative labeled data, comes in handy
for such a scenario. In this work, we present D2ADA, a general active domain
adaptation framework for semantic segmentation. To adapt the model to the
target domain with minimum queried labels, we propose acquiring labels of the
samples with high probability density in the target domain yet with low
probability density in the source domain, complementary to the existing source
domain labeled data. To further facilitate labeling efficiency, we design a
dynamic scheduling policy to adjust the labeling budgets between domain
exploration and model uncertainty over time. Extensive experiments show that
our method outperforms existing active learning and domain adaptation baselines
on two benchmarks, GTA5 -> Cityscapes and SYNTHIA -> Cityscapes. With less than
5% target domain annotations, our method reaches comparable results with that
of full supervision.Comment: 14 pages, 5 figure
A model-based circular binary segmentation algorithm for the analysis of array CGH data
<p>Abstract</p> <p>Background</p> <p>Circular Binary Segmentation (CBS) is a permutation-based algorithm for array Comparative Genomic Hybridization (aCGH) data analysis. CBS accurately segments data by detecting change-points using a maximal-<it>t </it>test; but extensive computational burden is involved for evaluating the significance of change-points using permutations. A recent implementation utilizing a hybrid method and early stopping rules (hybrid CBS) to improve the performance in speed was subsequently proposed. However, a time analysis revealed that a major portion of computation time of the hybrid CBS was still spent on permutation. In addition, what the hybrid method provides is an approximation of the significance upper bound or lower bound, not an approximation of the significance of change-points itself.</p> <p>Results</p> <p>We developed a novel model-based algorithm, extreme-value based CBS (eCBS), which limits permutations and provides robust results without loss of accuracy. Thousands of aCGH data under null hypothesis were simulated in advance based on a variety of non-normal assumptions, and the corresponding maximal-<it>t </it>distribution was modeled by the Generalized Extreme Value (GEV) distribution. The modeling results, which associate characteristics of aCGH data to the GEV parameters, constitute lookup tables (eXtreme model). Using the eXtreme model, the significance of change-points could be evaluated in a constant time complexity through a table lookup process.</p> <p>Conclusions</p> <p>A novel algorithm, eCBS, was developed in this study. The current implementation of eCBS consistently outperforms the hybrid CBS 4× to 20× in computation time without loss of accuracy. Source codes, supplementary materials, supplementary figures, and supplementary tables can be found at <url>http://ntumaps.cgm.ntu.edu.tw/eCBSsupplementary</url>.</p
Lifshitz transition and van Hove singularity in a Topological Dirac Semimetal
A topological Dirac semimetal is a novel state of quantum matter which has
recently attracted much attention as an apparent 3D version of graphene. In
this paper, we report critically important results on the electronic structure
of the 3D Dirac semimetal Na3Bi at a surface that reveals its nontrivial
groundstate. Our studies, for the first time, reveal that the two 3D Dirac
cones go through a topological change in the constant energy contour as a
function of the binding energy, featuring a Lifshitz point, which is missing in
a strict 3D analog of graphene (in other words Na3Bi is not a true 3D analog of
graphene). Our results identify the first example of a band saddle point
singularity in 3D Dirac materials. This is in contrast to its 2D analogs such
as graphene and the helical Dirac surface states of a topological insulator.
The observation of multiple Dirac nodes in Na3Bi connecting via a Lifshitz
point along its crystalline rotational axis away from the Kramers point serves
as a decisive signature for the symmetry-protected nature of the Dirac
semimetal's topological groundstate.Comment: 5 pages, 4 Figures, Related papers on topological Fermi arcs and Weyl
Semimetals (WSMs) are at
http://physics.princeton.edu/zahidhasangroup/index.htm
Weight Stigma Model on Quality of Life Among Children in Hong Kong: A Cross-Sectional Modeling Study
We proposed amodel to examine the relationship among different types of weight-related
stigmas and their relationship to quality of life (QoL). We recruited 430 dyads of
elementary school children [mean age = 10.07 years; nboy = 241 (56.0%); noverweight =
138 (32.1%)] and their parents. Parents completed QoL instruments about their children
assessing generic QoL and weight-related QoL. Children completed QoL instruments
assessing generic QoL and weight-related QoL and stigma scales assessing experienced
weight stigma, weight-related self-stigma, and perceived weight stigma. Experienced
weight stigma was significantly associated with perceived weight stigma, and in turn,
perceived weight stigma was significantly associated with weight-related self-stigma.
However, experienced weight stigma was not directly associated with weight-related
self-stigma. In addition, experienced stigma was negatively associated with both
child-rated and parent-rated QoL. Perceived weight stigma was associated only with
parent-rated weight-related QoL but not child-rated QoL. Self-stigma was associated
with child-rated QoL but not parent-rated QoL. Moreover, perceived weight stigma and
weight-related self-stigma were significant mediators in the association between body
weight and children’s QoL; experienced weight stigma was not a significant mediator.
The study findings can be used to inform healthcare providers about the relationship
among different types of stigmas and their influence on child-rated and parent-rated QoL
and help them develop interventions to address the global trend of overweight/obesity
in youth and pediatric populations
Conformational surveillance of Orai1 by a rhomboid intramembrane protease prevents inappropriate CRAC channel activation
Calcium influx through plasma membrane calcium release-activated calcium (CRAC) channels, which are formed of hexamers of Orai1, is a potent trigger for many important biological processes, most notably in T cell-mediated immunity. Through a bioinformatics-led cell biological screen, we have identified Orai1 as a substrate for the rhomboid intramembrane protease RHBDL2. We show that RHBDL2 prevents stochastic calcium signaling in unstimulated cells through conformational surveillance and cleavage of inappropriately activated Orai1. A conserved disease-linked proline residue is responsible for RHBDL2’s recognizing the active conformation of Orai1, which is required to sharpen switch-like signaling triggered by store-operated calcium entry. Loss of RHBDL2 control of CRAC channel activity causes severe dysregulation of downstream CRAC channel effectors, including transcription factor activation, inflammatory cytokine expression, and T cell activation. We propose that this surveillance function may represent an ancient activity of rhomboid proteases in degrading unwanted signaling proteins
Herschel Observations of Major Merger Pairs at z=0: Dust Mass and Star Formation
We present Herschel PACS and SPIRE far-infrared (FIR) and submillimeter imaging observations for a large K-band selected sample of 88 close major-merger pairs of galaxies (H-KPAIRs) in 6 photometric bands (70, 100, 160, 250, 350, and 500 μm). Among 132 spiral galaxies in the 44 spiral–spiral (S+S) pairs and 44 spiral–elliptical (S+E) pairs, 113 are detected in at least 1 Herschel band. The star formation rate (SFR) and dust mass (M_(dust)) are derived from the IR SED fitting. The mass of total gas (M_(gas)) is estimated by assuming a constant dust-to-gas mass ratio of 0.01. Star-forming spiral galaxies (SFGs) in S+S pairs show significant enhancements in both specific star formation rate (sSFR) and star formation efficiency (SFE), while having nearly the same gas mass compared to control galaxies. On the other hand, for SFGs in S+E pairs, there is no significant sSFR enhancement and the mean SFE enhancement is significantly lower than that of SFGs in S+S pairs. This suggests an important role for the disk–disk collision in the interaction-induced star formation. The M_(gas) of SFGs in S+E pairs is marginally lower than that of their counterparts in both S+S pairs and the control sample. Paired galaxies with and without interaction signs do not differ significantly in their mean sSFR and SFE. As found in previous works, this much larger sample confirms that the primary and secondary spirals in S+S pairs follow a Holmberg effect correlation on sSFR
A colliding maxillary sinus cancer of adenosquamous carcinoma and small cell neuroendocrine carcinoma - a case report with EGFR copy number analysis
<p>Abstract</p> <p>Background</p> <p>Small cell neuroendocrine carcinoma (SNEC) of maxillary sinus is a rare and aggressive malignancy. A tumor with squamous cell carcinoma, adenocarcinoma and SNEC co-existence is extremely rare.</p> <p>Case presentation</p> <p>We present a colliding tumor of squamous cell, adenocarcinoma and SNEC in maxillary sinus. The clinical features, diagnosis and EGFR flourescence in situ hybridization (FISH) study are presented. A 52-year-old female had a 1-month history of progressing left cheek swelling and purulent rhinorrhea. Magnetic resonance imaging showed a tumor involving left maxilla and orbital floor. Excision of tumor was done and the defect was reconstructed with free flap. The pathology revealed a malignant tumor composed of squamous cell carcinoma, adenocarcinoma and SNEC components. EGFR FISH study showed no gene amplification in 3 components of this tumor. The tumor progressed rapidly and the patient expired at 8 months after surgery.</p> <p>Conclusion</p> <p>A colliding tumor of squamous cell, adenocarcinoma and neuroendocrine carcinoma in maxillary sinus was aggressive in behavior and the treatment response was poor due to the complexity of tumor.</p
- …