Drivers of vegetation and soil determine natural regeneration of a single plantation at different slope positions

Promoting natural regeneration in artificial forest ecosystems is crucial for sustainable management. Understanding the fundamental mechanisms and drivers of tree regeneration is the prerequisite for promoting it effectively. This study worked with Larix principis-rupprechtii, a species considered difficult to regenerate. Twenty-four sample plots measuring 30 m × 30 m were established, with eight plots at each of the lower, middle, and upper slope positions, respectively. Field investigation and multivariate analysis were performed to uncover the regeneration traits in the plantations with abundant seedlings on the continuous slope. The results revealed that ground diameter and height of the regeneration (RGD and RH) were larger at the lower slope, with significant positive correlations to available nitrogen (contribution rate, CR: 0.858) and slope (CR: 0.652). In contrast, regeneration density (RD), representing the quantity of regeneration, was greater at the middle slope. Its significant impact factors were slope position (CR: −0.648) and herb diversity, represented by Pielou index (CR: 0.961). Stand density had a significant negative effect on regeneration, particularly at the upper slope, with CRs of −0.842 and −0.764 to RGD/RH and RD, respectively. Common contribution was found among the factors, with the largest contribution groups being the topographical and soil factors (CR: 0.358). These findings provide valuable insights into the single species regeneration progress on northern mountainous slopes and offer essential information for developing facilitation methods for the natural regeneration in artificial forests

Insight-HXMT observations of Swift J0243.6+6124 during its 2017-2018 outburst

The recently discovered neutron star transient Swift J0243.6+6124 has been monitored by {\it the Hard X-ray Modulation Telescope} ({\it Insight-\rm HXMT). Based on the obtained data, we investigate the broadband spectrum of the source throughout the outburst. We estimate the broadband flux of the source and search for possible cyclotron line in the broadband spectrum. No evidence of line-like features is, however, found up to $\rm 150~keV$. In the absence of any cyclotron line in its energy spectrum, we estimate the magnetic field of the source based on the observed spin evolution of the neutron star by applying two accretion torque models. In both cases, we get consistent results with $B\rm \sim 10^{13}~G$, $D\rm \sim 6~kpc$ and peak luminosity of $\rm >10^{39}~erg~s^{-1}$ which makes the source the first Galactic ultraluminous X-ray source hosting a neutron star.Comment: publishe

Overview to the Hard X-ray Modulation Telescope (Insight-HXMT) Satellite

As China's first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band (1-250 keV) slat-collimator-based X-ray astronomy satellite with the capability of all-sky monitoring in 0.2-3 MeV. It was designed to perform pointing, scanning and gamma-ray burst (GRB) observations and, based on the Direct Demodulation Method (DDM), the image of the scanned sky region can be reconstructed. Here we give an overview of the mission and its progresses, including payload, core sciences, ground calibration/facility, ground segment, data archive, software, in-orbit performance, calibration, background model, observations and some preliminary results.Comment: 29 pages, 40 figures, 6 tables, to appear in Sci. China-Phys. Mech. Astron. arXiv admin note: text overlap with arXiv:1910.0443

Clinical characteristics of coronavirus disease 2019 (COVID-19) patients with hypertension on renin–angiotensin system inhibitors

In December 2019, COVID-19 outbroke in Wuhan, China. The current study aimed to explore the clinical characteristics of COVID-19 complicated by hypertension. In this retrospective, single-center study, we recruited 110 discharged patients with COVID-19 at Wuhan Fourth Hospital in Wuhan, China, from January 25 to February 20, 2020. All study cases were grouped according to whether they had a history of hypertension. Then, a subgroup analysis for all hypertensive patients was carried out based on whether to take ACEI or ARB drugs. The mean age of 110 patients was 57.7 years (range, 25–86 years), of which 60 (54.5%) were male patients. The main underlying diseases included hypertension [36 (32.7%)] and diabetes [11 (10.0%)]. Compared with the non-hypertensive group, the lymphocyte count was significantly lower in the hypertensive group (average value, 0.96 × 109/L vs 1.26 × 109/L), and analysis of clinical outcomes showed that the crude mortality rate was higher in the hypertensive group [7/36 (19.4%) vs 2/74 (2.7%)]. Patients treated with ACEI or ARB, compared with the control group, were younger (average age, 58.5 years vs 69.2 years), but there was no statistical difference in the crude cure rate [10/15 (66.7%) vs 15/21 (71.4%)] and the crude mortality rate [2/15 (13.3%) vs 5/21 (23.8%)]. In conclusions, the COVID-19 patients with a history of hypertension had a significantly lower lymphocyte count on admission. The elderly and comorbidities such as hypertension may together constitute risk factors for poor prognosis in patients with COVID-19. Taking ACEI or ARB drugs may not change the prognosis of COVID-19 patients with hypertension

Motion-Based Multiple Object Tracking of Ultrasonic-Induced Nucleation: A Case Study of l‑Glutamic Acid

A robust nucleation tracking technology was proposed to track the nucleation process of l-glutamic acid in this study. A motion-based multiple object tracking (MMOT) model was introduced to crystallization, for the first time, to help to track the moving crystals. A waterproof microcamera combined with a home-designed vial adaptor was used to record the nucleation process video stream. Optimization of parameters in the MMOT model and a moving average (MA) based smoothing method helped to determine the starting point of nucleation. Results showed the newly developed technology performed better under the influence of ultrasonic irradiation, which disabled the use of focused beam reflection measurement (FBRM)