100 research outputs found
Sequential Star Formation in the filamentary structures of Planck Galactic cold clump G181.84+0.31
We present a multi-wavelength study of the Planck cold clump G181.84+0.31,
which is located at the northern end of the extended filamentary structure
S242. We have extracted 9 compact dense cores from the SCUBA-2 850 um map, and
we have identified 18 young stellar objects (YSOs, 4 Class I and 14 Class II)
based on their Spitzer, Wide-field Infrared Survey Explorer (WISE) and
Two-Micron All-Sky Survey (2MASS) near- and mid-infrared colours. The dense
cores and YSOs are mainly distributed along the filamentary structures of
G181.84 and are well traced by HCO(1-0) and NH(1-0)
spectral-line emission. We find signatures of sequential star formation
activities in G181.84: dense cores and YSOs located in the northern and
southern sub-structures are younger than those in the central region. We also
detect global velocity gradients of about 0.80.05 km spc and
1.00.05 km spc along the northern and southern
sub-structures, respectively, and local velocity gradients of 1.20.1 km
spc in the central substructure. These results may be due to the
fact that the global collapse of the extended filamentary structure S242 is
driven by an edge effect, for which the filament edges collapse first and then
further trigger star formation activities inward. We identify three
substructures in G181.84 and estimate their critical masses per unit length,
which are 10115 M pc, 568 M
pc and 284 M pc, respectively. These values are
all lower than the observed values ( 200 M pc),
suggesting that these sub-structures are gravitationally unstable.Comment: 20 pages, 17 figures, article, accepte
Effects of equivalence ratio, inlet temperature and pressure on NO emissions for two stage combustion of NH3/H2 fuel mixture
High-speed Gaussian modulated continuous-variable quantum key distribution with a local local oscillator based on pilot-tone-assisted phase compensation
A high-speed Gaussian modulated continuous-variable quantum key distribution
(CVQKD) with a local local oscillator (LLO) is experimentally demonstrated
based on pilot-tone-assisted phase compensation. In the proposed scheme, the
frequency-multiplexing and polarization-multiplexing techniques are used for
the separate transmission and heterodyne detection between quantum signal and
pilot tone, guaranteeing no crosstalk from strong pilot tone to weak quantum
signal and different detection requirements of low-noise for quantum signal and
high-saturation limitation for pilot tone. Moreover, compared with the
conventional CVQKD based on homodyne detection, the proposed LLO-CVQKD scheme
can measure X and P quadrature simultaneously using heterodyne detection
without need of extra random basis selection. Besides, the phase noise, which
contains the fast-drift phase noise due to the relative phase of two
independent lasers and the slow-drift phase noise introduced by quantum channel
disturbance, has been compensated experimentally in real time, so that a low
level of excess noise with a 25km optical fiber channel is obtained for the
achievable secure key rate of 7.04 Mbps in the asymptotic regime and 1.85 Mbps
under the finite-size block of 10^7
Pose-Oriented Transformer with Uncertainty-Guided Refinement for 2D-to-3D Human Pose Estimation
There has been a recent surge of interest in introducing transformers to 3D
human pose estimation (HPE) due to their powerful capabilities in modeling
long-term dependencies. However, existing transformer-based methods treat body
joints as equally important inputs and ignore the prior knowledge of human
skeleton topology in the self-attention mechanism. To tackle this issue, in
this paper, we propose a Pose-Oriented Transformer (POT) with uncertainty
guided refinement for 3D HPE. Specifically, we first develop novel
pose-oriented self-attention mechanism and distance-related position embedding
for POT to explicitly exploit the human skeleton topology. The pose-oriented
self-attention mechanism explicitly models the topological interactions between
body joints, whereas the distance-related position embedding encodes the
distance of joints to the root joint to distinguish groups of joints with
different difficulties in regression. Furthermore, we present an
Uncertainty-Guided Refinement Network (UGRN) to refine pose predictions from
POT, especially for the difficult joints, by considering the estimated
uncertainty of each joint with uncertainty-guided sampling strategy and
self-attention mechanism. Extensive experiments demonstrate that our method
significantly outperforms the state-of-the-art methods with reduced model
parameters on 3D HPE benchmarks such as Human3.6M and MPI-INF-3DHPComment: accepted by AAAI202
Evaluation and Analysis of Hallucination in Large Vision-Language Models
Large Vision-Language Models (LVLMs) have recently achieved remarkable
success. However, LVLMs are still plagued by the hallucination problem, which
limits the practicality in many scenarios. Hallucination refers to the
information of LVLMs' responses that does not exist in the visual input, which
poses potential risks of substantial consequences. There has been limited work
studying hallucination evaluation in LVLMs. In this paper, we propose
Hallucination Evaluation based on Large Language Models (HaELM), an LLM-based
hallucination evaluation framework. HaELM achieves an approximate 95%
performance comparable to ChatGPT and has additional advantages including low
cost, reproducibility, privacy preservation and local deployment. Leveraging
the HaELM, we evaluate the hallucination in current LVLMs. Furthermore, we
analyze the factors contributing to hallucination in LVLMs and offer helpful
suggestions to mitigate the hallucination problem. Our training data and human
annotation hallucination data will be made public soon.Comment: 11 pages, 5 figure
Fecal Pharmacokinetics and Gut Microbiome Effects of oral Omadacycline Versus Vancomycin in Healthy Volunteers
BACKGROUND: Clostridioides difficile infection (CDI) is a common healthcare-associated infection with limited treatment options. Omadacycline, an aminomethylcycline tetracycline, has potent in vitro activity against C difficile and a low propensity to cause CDI in clinical trials. We aimed to assess fecal pharmacokinetics and gut microbiome effects of oral omadacycline compared to oral vancomycin in healthy adults.
METHODS: This was a phase 1, nonblinded, randomized clinical trial conducted in healthy volunteers aged 18-40 years. Subjects received a 10-day course of omadacycline or vancomycin. Stool samples were collected at baseline, daily during therapy, and at follow-up visits. Omadacycline and vancomycin stool concentrations were assessed, and microbiome changes were compared.
RESULTS: Sixteen healthy volunteers with a mean age of 26 (standard deviation [SD], 5) years were enrolled; 62.5% were male, and participants\u27 mean body mass index was 23.5 (SD, 4.0) kg/m2. Omadacycline was well tolerated with no safety signal differences between the 2 antibiotics. A rapid initial increase in fecal concentrations of omadacycline was observed compared to vancomycin, with maximum concentrations achieved within 48 hours. A significant difference in alpha diversity was observed following therapy in both the omadacycline and vancomycin groups (P \u3c .05). Bacterial abundance and beta diversity analysis showed differing microbiome changes in subjects who received omadacycline versus vancomycin.
CONCLUSIONS: Subjects given omadacycline had high fecal concentrations with a distinct microbiome profile compared to vancomycin.
CLINICAL TRIALS REGISTRATION: NCT06030219
Impact of intestinal microbiota on metabolic toxicity and potential detoxification of amygdalin
Amygdalin (Amy) is metabolized into cyanide in vivo, which may lead to fatal poisoning after oral administration. The defense mechanisms against toxic cyanide have not yet been adequately studied. In this study, comparative toxicokinetics study of Amy was performed in normal and pseudo germ-free rats. The efficiency of cyanide release was significant higher in normal group when given a single oral dose of 440 mg/kg (50% median lethal dose). Thiocyanate, the detoxification metabolite, was firstly detected in feces, caecum, and intestinal microbiota incubation enzymic system. The results suggest intestinal microbiota is involved in bidirectional regulation of toxicity and detoxification of Amy. We further identified the species related to cyanogenesis of Amy with metagenomic sequencing, such as Bifidobacterium pseudolongum, Marvinbryantia formatexigens, and Bacteroides fragilis. Functional analysis of microbiota reveals the detoxification potential of intestinal microbiota for cyanide. Sulfurtransferase superfamily, such as rhodanese, considered as main detoxification enzymes for cyanide, are largely found in Coriobacteriaceae bacterium, Butyricicoccus porcorum, Akkermansia muciniphila, etc. Besides, cyanoamino acid metabolism pathway dominated by Escherichia coli may contribute to the detoxification metabolism of cyanide. In summary, intestinal microbiota may be the first line of defense against the toxicity induced by Amy
Corrigendum: Impact of intestinal microbiota on metabolic toxicity and potential detoxification of amygdalin
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