820 research outputs found
Anomalous orbital expansion of low-mass X-ray binary 2A 1822-371: the existence of a circumbinary disk?
The source 2A 1822-371 is an eclipsing low-mass X-ray binary (LMXB)
consisting of a neutron star (NS) and a donor star in an
orbit of 5.57 hr. Based on timing of the eclipse arrival times, this source was
found to be experiencing a rapid orbital expansion with an orbital-period
derivative as ,
implying that the mass-transfer rate should be higher than at least three times
the Eddington accretion rate. The standard magnetic braking (MB) model cannot
produce such a high mass-transfer rate. The modified MB model derived by Van \&
Ivanova (2019) can produce a high mass-transfer rate, resulting in a high
. This work proposes an alternative model to account for the
anomalously high mass-transfer rate and of 2A 1822-371.
During the mass transfer, a tiny fraction of the transferred material is
thought to form a circumbinary (CB) disk around the LMXB, which can efficiently
extract orbital angular momentum from the system by the interaction between the
CB disk and the binary. We use the MESA code to model the formation and
evolution of 2A 1822-371 for different CB-disk masses. When the CB-disk mass is
, the simulation can reproduce the observed
donor-star mass, orbital period, and orbital-period derivative. Such a CB disk
can accelerate the evolution of the binary and produce a high mass transfer
rate of , driving the binary to evolve
toward a wide-orbit system. Therefore, we propose that CB disks may be
responsible for the rapid orbital changes observed in some LMXBs.Comment: 8 pages, 8 figures, Astronomy and Astrophysics in pres
Anti-hyperprolactinemia mechanism of Radix bupleuri extract in rats
Purpose: To determine the mechanism underlying the anti-hyperprolactinemia effects of Radix bupleuri extract (RBE) in rats.Methods: Rats were divided into six groups (n=10 each group): healthy controls, untreated hyperprolactinemic rats, hyperprolactinemic rats treated with bromocriptine (0.6 mg/kg), and hyperprolactinemic rats treated with RBE (4.8, 9.6, or 19.2 g/kg). After 30 days, hypothalamic protein levels of dopamine D2 receptor, protein kinase A (PKA), and cyclic adenosine monophosphate (cAMP) were determined.Results: Dopamine D2 receptor levels were lower in untreated hyperprolactinemic rats than in healthy controls (p < 0.01), but this decrease was attenuated by RBE (p < 0.05). Elevated PKA levels in untreated hyperprolactinemic rats (0.61 ± 0.04 μg/ml, p < 0.01) were decreased by RBE (4.8 g/kg, 0.42 ± 0.03 μg/ml, p < 0.05; 9.6 g/kg, 0.33 ± 0.02 μg/ml, p < 0.01; 19.2 g/kg, 0.27 ± 0.03 μg/ml, p < 0.01). Similarly, elevated cAMP levels in hyperprolactinemic rats (2.4 ± 0.4 ng/ml) were decreased by RBE (4.8 g/kg, 1.8 ± 0.3 ng/ml, p < 0.05; 9.6 g/kg, 1.5 ± 0.3 ng/ml, p < 0.01; 19.2 g/kg, 1.2 ± 0.2 ng/ml, p < 0.01).Conclusions: RBE anti-hyperprolactinemia activity is mediated by dopamine D2 receptor signaling via the cAMP/PKA pathway.Keywords: Hyperprolactinemia, Radix bupleuri, Dopamine D2 receptor, cAMP/PK
Bottleneck Analysis of Dynamic Graph Neural Network Inference on CPU and GPU
Dynamic graph neural network (DGNN) is becoming increasingly popular because
of its widespread use in capturing dynamic features in the real world. A
variety of dynamic graph neural networks designed from algorithmic perspectives
have succeeded in incorporating temporal information into graph processing.
Despite the promising algorithmic performance, deploying DGNNs on hardware
presents additional challenges due to the model complexity, diversity, and the
nature of the time dependency. Meanwhile, the differences between DGNNs and
static graph neural networks make hardware-related optimizations for static
graph neural networks unsuitable for DGNNs. In this paper, we select eight
prevailing DGNNs with different characteristics and profile them on both CPU
and GPU. The profiling results are summarized and analyzed, providing in-depth
insights into the bottlenecks of DGNNs on hardware and identifying potential
optimization opportunities for future DGNN acceleration. Followed by a
comprehensive survey, we provide a detailed analysis of DGNN performance
bottlenecks on hardware, including temporal data dependency, workload
imbalance, data movement, and GPU warm-up. We suggest several optimizations
from both software and hardware perspectives. This paper is the first to
provide an in-depth analysis of the hardware performance of DGNN Code is
available at https://github.com/sharc-lab/DGNN_analysis.Comment: 14 pages main text, 2 pages appendix, 10 figures, submitted to
IISWC202
The Current Progress in Research about the Effect of Phenolics from Brown Rice on the Digestibility of Starch
Chronic diseases inclding diabetes have been important public health problems worldwide. Starch intake is one of the main causes of postprandial blood glucose elevation. Recent studies have demonstrated that polyphenols can slow down the rate of starch digestion. Brown rice is rich in phenolics, and its nutritional health benefits are widely recognized around the world as an essential source of whole grains. The unique functional groups of phenolic substances in brown rice, such as phenolic hydroxyl, have a certain inhibitory effect on digestive enzymes. Changes in the structure of starch during processing also decrease the effect of digestive enzymes on it. This not only affects the digestion rate and digestibility of starch in an effective way, but also improves food quality. This paper reviews several aspects of phenolics in brown rice and their antioxidant activities, the process of starch digestion, the effects of brown rice polyphenols on starch digestive properties and their mechanisms of action. The aim of this review is to elucidate the scientific basis of whole grain brown rice polyphenols to retard starch digestion, and provide theoretical references for the development of whole grain brown rice-based and starch-based foods which are beneficial for populations of chronic disease, obesity, overweight, elderly, etc
Research Progress on γ-Oryzanol in Rice and its Processed By-Product Rice Bran
China is one the of the major production country of paddy rice, while during the processing of paddy rice, there is usually a high portion of nutrients loss and rice bran by-products are produced.γ-oryzanol is a mixture of bioactive compounds in the unsaponifiable part of rice bran layer. Research has been focusing on it in recent years due to its outstanding physiological functions. This paper reviews the effects of rice raw materials, precision of rice processing, rice processing methods on the content of γ-oryzanol and the research progress on the extraction of γ-oryzanol from rice bran. We suggest to stress the importance of the data collection of γ-oryzanol content of rice, advocate moderate processing of rice, develop brown rice products by extrusion, advance germination and fermentation techniques, and strengthen the separation of active components from rice bran. This is in line with the major development strategies of grain saving and waste reduction, which helps build a healthy China and support high quality development of China
Primary Tumor Standardized Uptake Value Measured on F18-Fluorodeoxyglucose Positron Emission Tomography Is of Prediction Value for Survival and Local Control in Non–Small-Cell Lung Cancer Receiving Radiotherapy: Meta-Analysis
Introduction:The 2-[18F]-Fluorodeoxyglucose (FDG) positron emission tomography (PET/CT) has become an imaging tool for clinical assessment of tumor, node, metastasis in non–small-cell lung cancer (NSCLC). Primary tumor maximum standardized uptake value (SUVmax) on 18F-FDG PET/CT before and after radiation therapy (RT) has been studied as a potential prognostic factor for NSCLC patients receiving radiotherapy. However, the sample sizes of most studies were small, and the results of the prediction value of SUVmax remained undetermined, which lead us to perform a meta-analysis to improve the precision in estimating its effect.Methods:We performed a meta-analysis of published literature for primary tumor SUVmax-based biomarkers of the outcome of NSCLC receiving radiotherapy. The required data for estimation of individual hazard ratios (HRs) to compare patients with a low and a high SUVmax were extracted from each publication. A combined HR was calculated by Stata statistical software (Version 11). All of the results were verified by two persons to ensure its accuracy.Results:Thirteen studies were finally included into this meta-analysis; data are available in 13 studies for pre-RT primary tumor SUVmax and in five studies for post-RT. For overall survival, the combined HR estimate was 1.05 (95% confidence interval [CI], 1.02–1.08) and 1.32 (95% CI, 1.15–1.51) for pre-RT SUVmax and post-RT SUVmax, respectively; 1.26 (95% CI, 1.05–1.52) and 2.01 (95% CI, 1.16–3.46) for local control (LC). In stereotactic body radiotherapy (SBRT) group, HR for LC was 1.11 (95% CI, 1.06–1.18) and 2.19 (95% CI, 1.34–3.60) for pre-SBRT SUVmax and post-SBRT SUVmax, respectively.Conclusion:Both pre-RT and post-RT primary tumor SUVmax can predict the outcome of patients with NSCLC treated with radiotherapy. Patients with high levels of pre-RT SUVmax seemed to have poorer overall survival and LC
Polygamy relation of quantum correlations with equality
We provide a generalized definition of polygamy relations for any quantum
correlation measures. Instead of the usual polygamy inequality, a polygamy
relation with equality is given by introducing the polygamy weight. From the
polygamy relation with equality, we present polygamy inequalities satisfied by
the th power of the quantum correlation measures. Taking
concurrence of assistance as an example, we further illustrate the significance
and advantages of these relations. We also obtain a polygamy relation with
equality by considering the one-to-group entanglements for any quantum
entanglement measures that do not satisfy the polygamy relations. We
demonstrate that such relations for tripartite states can be generalized to
multipartite systems
A strange star scenario for the formation of isolated millisecond pulsars
According to the recycling model, neutron stars in low-mass X-ray binaries
were spun up to millisecond pulsars (MSPs), which indicates that all MSPs in
the Galactic plane ought to be harbored in binaries. However, about
Galactic field MSPs are found to be solitary. To interpret this problem, we
assume that the accreting neutron star in binaries may collapse and become a
strange star when it reaches some critical mass limit. Mass loss and a weak
kick induced by asymmetric collapse during the phase transition (PT) from
neutron star to strange star can result in isolated MSPs. In this work, we use
a population-synthesis code to examine the PT model. The simulated results show
that a kick velocity of can produce
isolated MSPs and birth rate of in the
Galaxy, which is approximately in agreement with predictions from observations.
For the purpose of comparisons with future observation, we also give the mass
distributions of radio and X-ray binary MSPs, along with the delay time
distribution.Comment: 9 pages, 11 figures, accepted to publish on A&
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