628 research outputs found
Hexyl (E)-3-(3,4-dihydroxyphenyl)acrylate
The title molecule, C15H20O4, has an E conformation about its C=C bond and is almost planar (r.m.s. deviation of all non-H atoms = 0.04 Å). The crystal structurere features O—H⋯O and C—H⋯O hydrogen bonds
(E)-Isopentyl 3-(3,4-dihydroxyphenyl)acrylate
The title compound, C14H18O4, a derivative of caffeic acid, has an E configuration about the C=C bond. The benzene ring is almost coplanar with the C=C—C(O)—O—C linker [maximum deviation = 0.050 (2) Å], making a dihedral angle of only 4.53 (2)°. In the molecule, the adjacent hydroxy groups form an O—H⋯O interaction. In the crystal, molecules are linked by O—H⋯O hydrogen bonds, generating a chain propagating in the [110] direction
Application of Variational Iteration Method for Dropping Damage Evaluation of the Suspension Spring Packaging System
The dropping damage evaluation for packaging system is essential for safe transportation and storage. A dynamic model of nonlinear cubic-quintic Duffing oscillator for the suspension spring packaging system was proposed. Then, a first-order approximate solution was obtained by applying He’s variable iteration method. Based on the results, a damage evaluation equation was derived, which reveals the main controlling physical parameters for damage potential of drop to packaged products concretely. Finally, the dropping damage boundary curves and surfaces for the system were discussed. It was found that decreasing the suspension angle can improve the safe region of the system
Delayed Warming Hiatus over the Tibetan Plateau
A reduction in the warming rate for the global surface temperature since the late 1990s has attracted much attention and caused a great deal of controversy. During the same time period, however, most previous studies have reported enhanced warming over the Tibetan Plateau (TP). In this study we further examined the temperature trend of the TP and surrounding areas based on the homogenized temperature records for the period 1980–2014, we found that for the TP regions lower than 4000 m the warming rate has started to slow down since the late 1990s, a similar pattern consistent with the whole China and the global temperature trend. However, for the TP regions higher than 4000 m, this reduction in warming rate did not occur until the mid‐2000s. This delayed warming hiatus could be related to changes in regional radiative, energy, and land surface processes in recent years
A Graph-Temporal fused dual-input Convolutional Neural Network for Detecting Sleep Stages from EEG Signals
This work was supported by the National Natural Science Foundation of China under Grant Nos. 61922062, and 61873181.Peer reviewedPostprin
Distantly-Supervised Named Entity Recognition with Uncertainty-aware Teacher Learning and Student-student Collaborative Learning
Distantly-Supervised Named Entity Recognition (DS-NER) effectively alleviates
the burden of annotation, but meanwhile suffers from the label noise. Recent
works attempt to adopt the teacher-student framework to gradually refine the
training labels and improve the overall robustness. However, we argue that
these teacher-student methods achieve limited performance because poor network
calibration produces incorrectly pseudo-labeled samples, leading to error
propagation. Therefore, we attempt to mitigate this issue by proposing: (1)
Uncertainty-aware Teacher Learning that leverages the prediction uncertainty to
guide the selection of pseudo-labels, avoiding the number of incorrect
pseudo-labels in the self-training stage. (2) Student-student Collaborative
Learning that allows the transfer of reliable labels between two student
networks instead of completely relying on all pseudo-labels from its teacher.
Meanwhile, this approach allows a full exploration of mislabeled samples rather
than simply filtering unreliable pseudo-labeled samples. Extensive experimental
results on five DS-NER datasets demonstrate that our method is superior to
state-of-the-art teacher-student methods
Single Nucleotide Polymorphisms of MicroRNA Processing Machinery Genes and Outcome of Hepatocellular Carcinoma
MicroRNA (miRNA)-related single nucleotide polymorphisms (miR-SNPs) can affect cancer development, treatment efficacy and patients prognosis. We examined 6 miR-SNPs in miRNA processing machinery genes including exportin 5 (XPO5) (rs11077), Ran-GTPase (RAN) (rs14035), Dicer (rs3742330), Trinucleotide Repeat Containing 6B (TNRC6B) (rs9623117), GEMIN3 (rs197412), GEMIN4 (rs2740348) in 108 surgically resected HCC patients and evaluated the impact of these miR-SNPs on HCC outcome. Among the 6 SNPs, only the A/A genotype of rs11077 located in XPO5 3′UTR was identified to associated independently with worse survival in HCC patients by multivariate analysis with relative risk, 0.395; 95% CI, 0.167–0.933; p = 0.034. This is the first study reporting that polymorphisms related to miRSNPs have prognostic value in hepatocellular carcinoma and identify the A/A genotype of rs11077 SNP site located in XPO5 3′UTR can help to predict worse prognosis in patients
A High‐resolution Atmospheric Dust Record for 1810–2004 A.D. Derived from an Ice Core in Eastern Tien Shan, Central Asia
Centennial‐scale, high‐resolution records of atmospheric dust conditions are rare in the arid and semiarid regions of central Asia, limiting our understanding of the regional climate and environmental changes and their potential driving forces. In this paper, we present an annually resolved atmospheric dust record covering the period of 1810–2004 A.D., reconstructed from an ice core retrieved at 4512 m above sea level from the Miaoergou Glacier in the eastern Tien Shan. The time series of dust flux for the past 195 years shows three periods of relatively low values (i.e., 1810–1829 A.D., 1863–1940 A.D., and 1979–2004 A.D.) and two periods of relatively high values (i.e., 1830–1862 A.D. and 1941–1978 A.D.). Spatial correlation analysis suggests possible regional factors controlling the dust flux, including antecedent summer precipitation, spring soil moisture, and near‐surface wind speed. In addition, the Miaoergou dust flux is closely associated with the winter index of the North Atlantic Oscillation (NAO) over the past two centuries, with high (low) dust periods coinciding with the negative (positive) phases of the NAO. The persistent relationship suggests that the NAO may have been a key driver on dust flux change over the arid regions between the Tien Shan and Kunlun Mountains
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