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In order to understand the interspecific and ecological relationships of为了解君子峰自然保护区极小种群观光木群落的种间关系和生态联系,加强观光木野生资源的保护,对群落优势树种的生态位特征和种间联结性进行研究。结果表明: 观光木、浙江润楠、木荷、赤杨叶的生态位宽度优势明显,是主要建群种;20个优势树种的190组种对中,有50.5%的种对生态位重叠值大于0.5,物种间生态位分化程度一般;观光木与其他19个物种生态位重叠度普遍较高,当资源不足时,有竞争风险;优势树种的总体联结性表现为显著正联结,群落处于相对稳定的演替后期

BACKGROUND Understanding a virus shedding patterns in body fluids/secretions is important to determine the samples to be used for diagnosis and to formulate infection control measures. AIM To investigate the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) shedding patterns and its risk factors. METHODS All laboratory-confirmed coronavirus disease 2019 patients with complete medical records admitted to the Shenzhen Third People’s Hospital from January 28, 2020 to March 8, 2020 were included. Among 145 patients (54.5% males; median age, 46.1 years), three (2.1%) died. The bronco-alveolar lavage fluid (BALF) had the highest virus load compared with the other samples. The viral load peaked at admission (3.3 × 108 copies) and sharply decreased 10 d after admission. RESULTS The viral load was associated with prolonged intensive care unit (ICU) duration. Patients in the ICU had significantly longer shedding time compared to those in the wards (P < 0.0001). Age > 60 years [hazard ratio (HR) = 0.6; 95% confidence interval (CI): 0.4-0.9] was an independent risk factor for SARS-CoV-2 shedding, while chloroquine (HR = 22.8; 95%CI: 2.3-224.6) was a protective factor. CONCLUSION BALF had the highest SARS-CoV-2 load. Elderly patients had higher virus loads, which was associated with a prolonged ICU stay. Chloroquine was associated with shorter shedding duration and increased the chance of viral negativity.

Neutrophil gelatinase-associated lipocalin (NGAL) is not only a biomarker of kidney injury but also a bone-derived factor involved in metabolism. We aimed to explore relationships between plasma NGAL and chronic kidney disease-mineral bone disorder (CKD-MBD) parameters in maintenance hemodialysis (MHD) patients. First, a cross sectional observational study, including 105 MHD patients, was conducted to explore relationships between plasma NGAL levels and CKD–MBD parameters. Second, impact of parathyroidectomy and auto-transplantation (PTX + AT) on plasma NGAL was investigated in 12 MHD patients with severe secondary hyperparathyroidism (SHPT). According to Spearman correlation analysis, plasma NGAL levels were positively correlated with female (r = 0.243, P = 0.012), vintage (r = 0.290, P = 0.003), Klotho (r = 0.234, P = 0.016), calcium(Ca) (r = 0.332, P = 0.001), alkaline phosphatase (ALP) (r = 0.401, P

AIMS The distribution of the spectrum of chronic kidney disease (CKD) has been found to vary with time. Limited information is available regarding the changing spectrum of secondary glomerular diseases (SGDs). To further investigate changes in the spectrum of SGDs, we performed a cross-sectional study. METHODS From June 2010 to May 2015, 5,935 patients from 37 hospitals in Shandong Province were involved in this study. The study was divided into five periods according to 1-year intervals. The patients were divided into four age groups. RESULTS Of the 5,935 patients with qualified specimens, 1,038 (17.5%) were diagnosed with a SGD. Lupus nephritis (LN) (27.6%) was the most frequently identified SGD, followed by Henoch-Schonlein purpura glomerulonephritis (HSPN) (21.7%) and diabetic nephropathy (DN) (21.6%). The prevalence rate of DN demonstrated an increasing trend, and this condition became the leading cause of renal biopsy in period 3 (29.3%). The proportion of patients with hepatitis B virus-associated nephritis (HBVAN) decreased from 14.7% in period 2 to 5.1% in period 5 (p

During milling of thin-walled components, obtaining minimum distortion is essential in order to achieve production goals. In this study, a mechanical model based on deformation machanism is established, and is help to analyse relationship between residual stress and deformation in component. Researched on simulation and experiment, the stress-deformation characteristics of different component shape is obtained. The results indicate that the deformation of thin-walled component in milling primarily depends on the distribution of initial residual stress, which can generate bending moment and lead to distortion. And then milling stress on the surface is easy to make bending moment baesd on this distortion, and make the deformation of component intensify.

The Taylor bubble wake structures of liquid nitrogen in circular tubes with five different inner diameters under various inclination angles were investigated using particle image velocimetry (PIV) technique. Optical distortions produced by tube curvature and the refractive index difference between the tube and fluid were corrected by a new correction algorithm, which requires fewer equations than the existing one. The uniform grid validation shows the maximum error of the developed algorithm is only 3%. Experimental results have shown that the criterion for determining the wake structure of Taylor bubble in normal atmospheric temperature fluid in vertical tube from reference is still applicable for liquid nitrogen at higher Eotvos numbers 173 and 226; but the criterion is no longer applicable when the Eotvos numbers are at lower values of 8, 22 and 57. For the inclined tube, the vortex size in Taylor bubble wake was found to increase with the decreasing of inclination angle.

The flow structures around continuous cryogenic Taylor bubbles in the concentric glass tube with different diameters were investigated using particle image velocimetry (PIV) technique under various inclination angles. Optical distortions produced by tube curvature and the refractive index differences between tube and fluid were corrected using ray tracing method. Based on the PIV results, the proper orthogonal decomposition (POD) method was used to investigate the effect of flow structure on the interaction of Taylor bubbles through the large-scale turbulent structures of POD modes. Four best-fitted curves for Taylor bubble interaction for different inclination angles were represented. A correlation for Taylor bubble formation was developed with the consideration of turbulence suppression, tube inner diameter, fluid properties, inclination angle, etc. The results demonstrate that the minimum stable distance attains the smallest value at . The correlation for Taylor bubble formation shows good agreement with the experimental data both in the present study and from its references.

An experimental study was performed to investigate the thermal performance of an inclined miniature mesh heat pipe using water-based CuO nanofluid as the working fluid. The study focused mainly on the effects of the inclination angle and the operating temperature on the heat transfer performance of the heat pipe using the nanofluid with the mass concentration of CuO nanoparticles of 1.0 wt%. The experiment was performed at three steady operating temperatures of 40 °C, 50 °C and 60 °C. Experimental results show that the inclination angle has a strong effect on the heat transfer performance of heat pipes using both water and the nanofluid. The inclination angle of 45° corresponds to the best thermal performance for heat pipes using both water and the nanofluid. The present investigation indicates that the thermal performance of an inclined miniature mesh heat pipe can be strengthened by using CuO nanofluid.

Ampere force and Lorentz force are two different definitions in the field of electromagnetism. Some teaching materials have been confused by the relations and differences of the tow definitions. Generally speaking, Ampere force is not the resultant of Lorentz force which all the free electrons have in the carrier wire, either in numerical value or orientation. Acting in numerical value, Ampere force equals the algebra sum of the Lorentz components forces which all the free electrons endured in the (L×B) directions.

The statistical parameters of Taylor bubbles in cryogenic slug flow along glass tube were studied experimentally for various inclination angles θ (0°–60° from the vertical direction) and four tube inner diameters D (14, 18, 25 and 32 mm) by using high speed digital camera. The distributions and mean values of initial formation position, and the length and velocity of Taylor bubbles along the tube at various inclination angles were obtained. Initial position of Taylor bubbles increases as tube inner diameter increases and the effect of tube diameter on Taylor bubble initial position becomes more obvious at θ ≥ 30°. Taylor bubble length shows an allometric decreasing trend with the increasing of tube inner diameter. The influence of inclination angle and axial position on the length and velocity of Taylor bubble in cryogenic slug flow agrees qualitatively with conventional air–water system. The maximum mean velocity of Taylor bubble occurs at 30° ≤ θ ≤ 45° and the minimum mean length of Taylor bubble occurs at 0° ≤ θ ≤ 20°. The Mean length of Taylor bubble increases along the tube for x/D ≤ 60. © 2011 Canadian Society for Chemical Engineering

A field campaign was conducted to measure and analyze 13 polycyclic aromatic hydrocarbons (PAHs) in six major zones in the city of Shanghai, P.R. China from August 2006 to April 2007. Ambient air samples were collected seasonally using passive air samplers, and gas chromatography-mass spectroscopy was used in this field campaign. The results showed that there was a sequence of 13 PAHs at Phen > FA > Pyr > Chr > Fl > An > BaA > BbFA > BghiP > IcdP > BkFA > BaP > DahA and the sum of these PAHs is 36.01 +/- 10.85 ng/m(3) in gas phase. FL, Phen, FA, Pyr, and Chr were the dominant PAHs in gas phase in the city. They contributed 90% of total PAHs in the gas phase. Proportion of measured PAHs with three, four, five, and six rings to total PAHs was 53%, 42%, 3%, and 2%, respectively. The highest concentration of SigmaPAHs (the sum of 13 PAHs) occurred in the wintertime and the lowest was in the summer. This investigation suggested that traffic, wood combustion, and metal scrap burn emissions were dominant sources of the concentrations of PAHs in six city zones compared with coal burning and industry emissions. Further, the traffic emission sources of PAHs in the city were attributed mostly to gasoline-powered vehicles compared with diesel-powered vehicles. It was revealed that the seasonal changes in PAHs in the city depended on different source types. Metal scrap burn was found to be the major source of PAHs during the autumn, while the PAH levels in the atmosphere for winter and spring seasons were mainly influenced by wood and biomass combustion. Comparisons of PAHs among different city zones and with several other cities worldwide were also made and discussed.

We present a semi-supervised learning algorithm to recognize feature vector noises in the training data. Our proposal employs an active contour model technology (ACM) which is used for objects extraction in the field of computer vision. We extend the ACM technology to the similarity formula of our proposal for identifying feature vector noises in the training set and improve the performance of the training data. The proposal is applied to the synthetic data and real data. The experiments prove that the proposal has a high performance on the feature vector noises in the unlabeled data of the training set.