Multi-messenger Study of Galactic Diffuse Emission with LHAASO and IceCube Observations

With the breakthrough in PeV gamma-ray astronomy brought by the LHAASO experiment, the high-energy sky is getting richer than before. Lately, LHAASO Collaboration reported the observation of a gamma-ray diffuse emission with energy up to the PeV level from both the inner and outer Galactic plane. In these spectra, there is one bump that is hard to explain by the conventional cosmic-ray transport scenarios. Therefore, we introduce two extra components corresponding to unresolved sources with exponential-cutoff-power-law (ECPL) spectral shape, one with an index of 2.4, and 20 TeV cutoff energy, and another with index of 2.3 and 2 PeV cutoff energy. With our constructed model, we simulate the Galactic diffuse neutrino flux and find our results are in full agreement with the latest IceCube Galactic plane search. We estimate the Galactic neutrino contributes of $\sim 9\%$ of astrophysical neutrinos at 20 TeV. In the high-energy regime, as expected most of the neutrinos observed by IceCube should be from extragalactic environments.Comment: 10 pages, 8 figures, comments are welcome, accepted by PR

Is Fermi 1544-0649 a misaligned blazar? discovering the jet structure with VLBI

Fermi J1544-0649 is a transient GeV source first detected during its GeV flares in 2017. Multi-wavelength observations during the flaring time demonstrate variability and spectral energy distribution(SED) that are typical of a blazar. Other than the flare time, Fermi J1544-0649 is quiet in the GeV band and looks rather like a quiet galaxy (2MASX J15441967-0649156) for a decade. Together with the broad absorption lines feature we further explore the "misaligned blazar scenario". We analyzed the Very Long Baseline Array (VLBA) and East Asian VLBI Network (EAVN) data from 2018 to 2020 and discovered the four jet components from Fermi J1544-0649. We found a viewing angle around 3.7{\deg} to 7.4{\deg}. The lower limit of the viewing angle indicates a blazar with an extremely low duty cycle of the gamma-ray emission, the upper limit of it supports the "misaligned blazar scenario". Follow-up multi-wavelength observations after 2018 show Fermi J1544-0649 remains quiet in GeV, X-ray, and optical bands. Multi-messenger search of neutrinos is also performed, and an excess of 3.1 {\sigma} significance is found for this source.Comment: Accepted for publication in ApJ. 13 pages, 7 figure

A Novel Reassortant Avian H7N6 Influenza Virus Is Transmissible in Guinea Pigs via Respiratory Droplets

Since 2013, H7N9 and H5N6 avian influenza viruses (AIVs) have caused sporadic human infections and deaths and continued to circulate in the poultry industry. Since 2014, H7N6 viruses which might be reassortants of H7N9 and H5N6 viruses, have been isolated in China. However, the biological properties of H7N6 viruses are unknown. Here, we characterize the receptor binding preference, pathogenicity and transmissibility of a H7N6 virus A/chicken/Hubei/00095/2017(H7N6) (abbreviated HB95), and a closely related H7N9 virus, A/chicken/Hubei/00093/2017(H7N9) (abbreviated HB93), which were isolated from poultry in Hubei Province, China, in 2017. Phylogenetic analyses demonstrated that the hemagglutinin (HA) gene of HB95 is closely related to those of HB93 and human-origin H7N9 viruses, and that the neuraminidase (NA) gene of HB95 shared the highest nucleotide similarity with those of H5N6 viruses. HB95 and HB93 had binding affinity for human-like α2, 6-linked sialic acid receptors and were virulent in mice without prior adaptation. In addition, in guinea pig model, HB93 was transmissible by direct contact, but HB95 was transmissible via respiratory droplets. These results revealed the potential threat to public health posed by H7N6 influenza viruses and emphasized the need for continued surveillance of the circulation of this subtype in poultry

Temperature and Emissivity Inversion Accuracy of Spectral Parameter Changes and Noise of Hyperspectral Thermal Infrared Imaging Spectrometers

The emergence of hyperspectral thermal infrared imaging spectrometers makes it possible to retrieve both the land surface temperature (LST) and the land surface emissivity (LSE) simultaneously. However, few articles focus on the problem of how the instrument’s spectral parameters and instrument noise level affect the LST and LSE inversion errors. In terms of instrument development, this article simulated three groups of hyperspectral thermal infrared data with three common spectral parameters and each group of data includes tens of millions of simulated radiances of 1525 emissivity curves with 17 center wavelength shift ratios, 6 full width at half maximum (FWHM) change ratios and 6 noise equivalent differential temperatures (NEDTs) under 15 atmospheric conditions with 6 object temperatures, inverted them by two temperature and emissivity separation methods (ISSTES and ARTEMISS), and analyzed quantitatively the effects of the spectral parameters change and noise of an instrument on the LST and LSE inversion errors. The results show that: (1) center wavelength shifts and noise affect the inversion errors strongly, while FWHM changes affect them weakly; (2) the LST and LSE inversion errors increase with the center wavelength shift ratio in a quadratic function and increase with FWHM change ratio slowly and linearly for both the inversion methods, however they increase with NEDT in an S-curve for ISSTES while they increase with NEDT slightly and linearly for ARTEMISS. During the design and development of a hyperspectral thermal infrared instrument, it is highly recommended to keep the potential center wavelength shift within 1 band and keep NEDT within 0.1K (corresponding LST error < 1K and LSE error < 0.015) for normal applications and within 0.03K (corresponding LST error < 0.5K and LSE error < 0.01) for better application effect and level

Discovery of Small-Molecule Antagonists of Orexin 1/2 Receptors from Traditional Chinese Medicinal Plants with a Hypnotic Effect

Insomnia is an important public health problem. The currently available treatments for insomnia can cause some adverse effects. Orexin receptors 1 (OX1R) and 2 (OX2R) are burgeoning targets for insomnia treatment. It is an effective approach to screening OX1R and OX2R antagonists from traditional Chinese medicine, which contains abundant and diverse chemical components. This study established an in-home ligand library of small-molecule compounds from medicinal plants with a definite hypnotic effect, as described in the Chinese Pharmacopoeia. Molecular docking was applied to virtually screen potential orexin receptor antagonists using molecular operating environment software, and surface plasmon resonance (SPR) technology was used to detect the binding affinity between potential active compounds and orexin receptors. Finally, the results of virtual screening and SPR analysis were verified through in vitro assays. We successfully screened one potential lead compound (neferine) as an orexin receptor antagonist from the in-home ligand library, which contained more than 1000 compounds. The screened compound was validated as a potential agent for insomnia treatment through comprehensive biological assays. This research enabled the discovery of a potential small-molecule antagonist of orexin receptors for the treatment of insomnia, providing a novel screening approach for the detection of potential candidate compounds for corresponding targets

Investigating Prompt Learning for Chinese Few-Shot Text Classification with Pre-Trained Language Models

Text classification aims to assign predefined labels to unlabeled sentences, which tend to struggle in real-world applications when only a few annotated samples are available. Previous works generally focus on using the paradigm of meta-learning to overcome the classification difficulties brought by insufficient data, where a set of auxiliary tasks is given. Accordingly, prompt-based approaches are proposed to deal with the low-resource issue. However, existing prompt-based methods mainly focus on English tasks, which generally apply English pretrained language models that can not directly adapt to Chinese tasks due to structural and grammatical differences. Thus, we propose a prompt-based Chinese text classification framework that uses generated natural language sequences as hints, which can alleviate the classification bottleneck well in low-resource scenarios. In detail, we first design a prompt-based fine-tuning together with a novel pipeline for automating prompt generation in Chinese. Then, we propose a refined strategy for dynamically and selectively incorporating demonstrations into each context. We present a systematic evaluation for analyzing few-shot performance on a wide range of Chinese text classification tasks. Our approach makes few assumptions about task resources and expertise and therefore constitutes a powerful, task-independent approach for few-shot learning

Comparison of different threshold values r for approximate entropy: application to investigate the heart rate variability between heart failure and healthy control groups

Approximate entropy (ApEn) is widely accepted as a complexity measure of the heart rate variability (HRV) signal, but selecting the criteria for the threshold value r is controversial. This paper aims to verify whether Chon's method of forecasting the r is an appropriate one for the HRV signal. The standard limb lead ECG signals of 120 subjects were recorded for 10 min in a supine position. The subjects were divided into two groups: the heart failure (22 females and 38 males, median age 62.4 ± 12.6) and healthy control group (33 females and 27 males, median age 51.5 ± 16.9). Three types of ApEn were calculated: the ApEn0.2 using the recommended constant r = 0.2, the ApEnchon using Chon's method and the ApEn using the true r. A Wilcoxon rank sum test showed that the ApEn (p = 0.267) and the ApEn (p = 0.813) had no statistical differences between the two groups, while the ApEn (p = 0.040) had. We generated a synthetic database to study the effect of two influential factors (the signal length N and the ratio of short-and long-term variability sd /sd) on the empirical formula in Chon's method (Chon et al 2009 IEEE Eng. Med. Biol. Mag. 28 18-23). The results showed that the empirical formula proposed by Chon et al is a good method for analyzing the random signal, but not an appropriate tool for analyzing nonlinear signals, such as the logistic or HRV signals

Palladium-Catalyzed Synthesis of 2,3,4-Trisubstituted Furans via Cascade Reactions of Aryloxy-enynes with Aryl Halides

A highly efficient palladium-catalyzed cascade reactions of aryloxy-enynes with aryl halides under mild reaction conditions has been developed. This methodology offers rapid access to 2,3,4-trisubstituted furans in good to excellent yields in a regioselective manner