26 research outputs found
Layer-refined Graph Convolutional Networks for Recommendation
Recommendation models utilizing Graph Convolutional Networks (GCNs) have
achieved state-of-the-art performance, as they can integrate both the node
information and the topological structure of the user-item interaction graph.
However, these GCN-based recommendation models not only suffer from
over-smoothing when stacking too many layers but also bear performance
degeneration resulting from the existence of noise in user-item interactions.
In this paper, we first identify a recommendation dilemma of over-smoothing and
solution collapsing in current GCN-based models. Specifically, these models
usually aggregate all layer embeddings for node updating and achieve their best
recommendation performance within a few layers because of over-smoothing.
Conversely, if we place learnable weights on layer embeddings for node
updating, the weight space will always collapse to a fixed point, at which the
weighting of the ego layer almost holds all. We propose a layer-refined GCN
model, dubbed LayerGCN, that refines layer representations during information
propagation and node updating of GCN. Moreover, previous GCN-based
recommendation models aggregate all incoming information from neighbors without
distinguishing the noise nodes, which deteriorates the recommendation
performance. Our model further prunes the edges of the user-item interaction
graph following a degree-sensitive probability instead of the uniform
distribution. Experimental results show that the proposed model outperforms the
state-of-the-art models significantly on four public datasets with fast
training convergence. The implementation code of the proposed method is
available at https://github.com/enoche/ImRec.Comment: 12 pages, 5 figure
Topological Electronic Structure Evolution with Symmetry Breaking Spin Reorientation in (FeCo)Sn
Topological materials hosting kagome lattices have drawn considerable
attention due to the interplay between topology, magnetism, and electronic
correlations. The (FeCo)Sn system not only hosts a kagome lattice
but has a tunable symmetry breaking magnetic moment with temperature and
doping. In this study, angle resolved photoemission spectroscopy and first
principles calculations are used to investigate the interplay between the
topological electronic structure and varying magnetic moment from the planar to
axial antiferromagnetic phases. A theoretically predicted gap at the Dirac
point is revealed in the low temperature axial phase but no gap opening is
observed across a temperature dependent magnetic phase transition. However,
topological surface bands are observed to shift in energy as the surface
magnetic moment is reduced or becomes disordered over time during experimental
measurements. The shifting surface bands may preclude the determination of a
temperature dependent bulk gap but highlights the intricate connections between
magnetism and topology with a surface/bulk dichotomy that can affect material
properties and their interrogation.Comment: 11 pages, 4 figure
Photochemical origin of SiC in the circumstellar envelope of carbon-rich AGB stars revealed by ALMA
Whether SiC is a parent species, that is formed in the photosphere or as
a by-product of high-temperature dust formation, or a daughter species, formed
in a chemistry driven by the photodestruction of parent species in the outer
envelope, has been debated for a long time. Here, we analyze the ALMA
observations of four SiC transitions in the CSEs of three C-rich AGB stars
(AI Vol, II Lup, and RAFGL 4211), and found that SiC exhibits an annular,
shell-like distribution in these targets, suggesting that SiC can be a
daughter species in the CSEs of carbon-rich AGB stars. The results can provide
important references for future chemical models.Comment: Accepted in Frontiers in Astronomy and Space Science
Research and Application of Polycarboxylic Acid Water Reducer with Different Molecular Weight
In this paper, a polycarboxylic water reducing agent was synthesized by using Methylallyl polyethylene glycol (HPEG) with molecular weight of 1200, 2400, 2800 and 3400 under the same conditions, C80 concrete tests were performed on these four molecular weight superplasticizers, verify the effect of different molecular weight polycarboxylic acid water reducer in C80 pumping concrete, finally, a kind of low molecular weight polycarboxylic acid water reducer with viscosity reducing effect in high-grade concrete is obtained, which can promote pumping of high-grade concrete
Research and Application of Polycarboxylic Acid Water Reducer with Different Molecular Weight
In this paper, a polycarboxylic water reducing agent was synthesized by using Methylallyl polyethylene glycol (HPEG) with molecular weight of 1200, 2400, 2800 and 3400 under the same conditions, C80 concrete tests were performed on these four molecular weight superplasticizers, verify the effect of different molecular weight polycarboxylic acid water reducer in C80 pumping concrete, finally, a kind of low molecular weight polycarboxylic acid water reducer with viscosity reducing effect in high-grade concrete is obtained, which can promote pumping of high-grade concrete
Analysis of Machine-made Sand Parameters in Shaanxi
Machine-made sand was significantly different from natural sand in terms of particle gradation, morphology, composition and structure. The concrete composed of mechanical sand and natural sand was greatly influenced by the physical and chemical properties of sand and gravel in terms of its microscopic appearance and macroscopic properties. Therefore, this paper aimed to systematically analyze the big data of machine-made sand performance testing, and focus on the fluctuation of the fineness modulus, stone powder content, and other indicators of machine-made sand particles in various regions of Shaanxi, and solve measures were further discussed
Chenodeoxycholic Acid Derivative HS-1200 Inhibits Hepatocarcinogenesis and Improves Liver Function in Diethylnitrosamine-Exposed Rats by Downregulating MTH1
Aim. To investigate the effects of HS-1200 on liver tumorigenesis and liver function in a diethylnitrosamine- (DEN-) induced hepatocellular carcinoma (HCC) rat model. Methods. Rats were randomly assigned into five groups: control, HS-1200, HCC, HCC + low dose HS-1200, and HCC + high dose HS-1200 groups. Rat HCC model was established by intraperitoneal injection of DEN. And rats were given HS-1200 by daily oral gavage. After 20 weeks, we examined animal body weight, liver weight, liver pathological changes, serum levels of AST, ALT, and AFP, and mutT homologue gene 1 (MTH1) in liver tissue. Results. Oral gavage of HS-1200 significantly increased animal body weight and decreased liver weight as well as liver coefficient in HCC rats (P<0.05 versus HCC group). Moreover, oral administration of HS-1200 suppressed tumorigenesis, attenuated pathological changes in liver tissues, and decreased serum levels of AST, ALT, and AFP in HCC rats (P<0.05 versus HCC group). In addition, the mRNA level of MTH1 was upregulated in the liver tissues of HCC rats (P<0.05 versus control group), which was reversed by HS-1200 treatment in a dose-dependent manner (P<0.05 versus HCC group). Conclusions. HS-1200 inhibits hepatocarcinogenesis and improves liver function maybe by inducing downregulation of MTH1
Influence of Topographic Shading on the Mass Balance of the High Mountain Asia Glaciers
Most studies attribute the glacier mass balance within High Mountain Asia (HMA) to climate change, ignoring the influence of its complex terrain. Knowledge of the influence of this complex terrain is crucial for understanding the spatial variability in its mass balance. However, there is a lack of any systematic assessment of this influence across HMA. Therefore, in this study, we used the glacier outlines and raster data (SRTM DEM, slope and aspect) to calculate the topographic shading of all 97,965 glaciers within HMA during the ablation period, which is regarded as a major index of the influence of complex terrain on the mass balance. The results showed that 27.19% of HMA glacier area was subjected to topographic shading, and regional differences were significant with respect to both their altitudinal and spatial distributions. The topographic shading contributed to the protection of the smallest glaciers from solar illumination. Furthermore, we found a significant correlation between the topographic shading and mass balance in these small north-facing glaciers. However, these small glaciers were most prevalent in the north-facing orientation, especially in West Kunlun, East Kunlun, Inner Tibet Plateau and Qilian Shan, where shading was found to increase with decreases in the glacier area. This indicates that complex terrain can affect the spatial distribution of the mass balance by altering the solar illumination pattern
Projections of glacier peak water and its timing in the Sanjiangyuan on the Tibet Plateau
Study region: The Sanjiangyuan, located on the Tibetan Plateau, is the headwater of the three large Asia Rivers- the Yangtze, Yellow and Lancang (upper Mekong) Rivers. Study focus: Mountain glacier melt runoff, an important buffer against drought, is enhancing with climate warming. Projection of glacier (especially small glaciers) runoff change is imperative for adapting to climate change and mitigating relevant risks. We aim to provide an up-to-date knowledge of the glacier area and runoff change for 2016–2099 in the Sanjiangyuan. New hydrological insights for the region: Projections based on CMIP6 archive show that 1) glacier area in the Sanjiangyuan for the four SSPs will shrink by 36 ± 12 % (SSP1–2.6), 42 ± 20 % (SSP2–4.5), 49 ± 19 % (SSP3–7.0) and 61 ± 15 % (SSP5–8.5) by the end of the 21st century. Small glacier dominated Lancang River basin is more sensitive to climate change than large glacier abundant Yangtze River basin and Yellow River basin. The Lancang River basin is projected to experience the greatest relative glacier area shrinkage, 10 % of glacier area and 55 % of glacier number will disappear for SSP5–8.5; 2) annual glacier runoff in the Yangtze River and Yellow River will reach peak water around 2080 under SSP3–7.0, while the Lancang River is already in or near peak water timing for all SSPs. Higher emission scenario tends to yield later peak water timing due to the changes in snow melt
Mapping and Identifying Candidate Genes Enabling Cadmium Accumulation in <i>Brassica napus</i> Revealed by Combined BSA-Seq and RNA-Seq Analysis
Rapeseed has the ability to absorb cadmium in the roots and transfer it to aboveground organs, making it a potential species for remediating soil cadmium (Cd) pollution. However, the genetic and molecular mechanisms underlying this phenomenon in rapeseed are still unclear. In this study, a ‘cadmium-enriched’ parent, ‘P1’, with high cadmium transport and accumulation in the shoot (cadmium root: shoot transfer ratio of 153.75%), and a low-cadmium-accumulation parent, ‘P2’, (with a cadmium transfer ratio of 48.72%) were assessed for Cd concentration using inductively coupled plasma mass spectrometry (ICP-MS). An F2 genetic population was constructed by crossing ‘P1’ with ‘P2’ to map QTL intervals and underlying genes associated with cadmium enrichment. Fifty extremely cadmium-enriched F2 individuals and fifty extremely low-accumulation F2 individuals were selected based on cadmium content and cadmium transfer ratio and used for bulk segregant analysis (BSA) in combination with whole genome resequencing. This generated a total of 3,660,999 SNPs and 787,034 InDels between these two segregated phenotypic groups. Based on the delta SNP index (the difference in SNP frequency between the two bulked pools), nine candidate Quantitative trait loci (QTLs) from five chromosomes were identified, and four intervals were validated. RNA sequencing of ‘P1’ and ‘P2’ in response to cadmium was also performed and identified 3502 differentially expressed genes (DEGs) between ‘P1’ and ‘P2’ under Cd treatment. Finally, 32 candidate DEGs were identified within 9 significant mapping intervals, including genes encoding a glutathione S-transferase (GST), a molecular chaperone (DnaJ), and a phosphoglycerate kinase (PGK), among others. These genes are strong candidates for playing an active role in helping rapeseed cope with cadmium stress. Therefore, this study not only sheds new light on the molecular mechanisms of Cd accumulation in rapeseed but could also be useful for rapeseed breeding programs targeting this trait