新媒体时代科普工作原则--基于CAS理论视角

简述了新媒体和复杂自适应系统（CAS）理论的相关概念,辨析了传统科普和新媒体时代科普的不同,指出了新媒体时代的科普系统是CAS ,提出了用CAS理论指导新媒体时代科普工作的几点原则。     

Study of wavelet denoising in apple's charge-coupled device near-infrared spectroscopy

Discrete wavelet transform was used to eliminate the noise in the charge-coupled device near-infrared (CCD-NIR) spectra of apple. The influence of three parameters (wavelet function, decomposition level, and threshold) on the predictive ability of the calibration model was investigated. The result showed that the db, sym, and bior wavelet families performed well, while the coif, dmey, and haar wavelets were not able to denoise effectively. The best decomposition level was 2. The threshold selection rules of the default, Birge-Massart, and Penalty had good denoising results, while SURE, Sqtwolog, Heuristic SURE, and Minimax set all detailed coefficients to zero due to their high threshold values. The best denoising result was obtained with the combination of the bior3.3 wavelet function, two levels of decomposition, default threshold selection rule, and the soft thresholding method. The optimal model of soluble solids content was constructed. The relative standard deviation of prediction decreased from 7.79 to 5.82% after wavelet denoising.     

Inhibition of low-density lipoprotein oxidation and oxidative burst in polymorphonuclear neutrophils by caffeic acid and hispidin derivatives isolated from sword brake fern (Pteris ensiformis Burm.)

Several antioxidant compounds have been previously identified from sword brake fern (Pteris ensiformis Burm.) by DPPH bleaching and Trolox equivalent antioxidant capacity (TEAC) analyses. Among the isolates, 7-O-caffeoylhydroxymaltol 3-O-beta-D-glucopyranoside and hispidin 4-O-beta- D-glucopyranoside [6-(3,4-dihydroxystyryl)-4-O-beta-D-glucopyranoside-2-pyrone] were two new compounds. The aim of this study is to elucidate the possible effect of the aqueous extract of sword brake fern (SBF) and these two compounds in preventing atherosclerosis. The results demonstrated that SBF and these two compounds strongly inhibited Cu2+-mediated low-density lipoprotein (LDL) oxidation measured by thiobarbituric acid-reactive substances assay (TBARS), conjugated diene production, and relative electrophoretic mobility. The commercial antioxidant dl-alpha-tocopherol showed lower antioxidant activity than these two compounds at the same molecular concentration. SBF and these two compounds also suppressed N-formylmethionyl-leucylphenylalanine (fMLP)-stimulated reactive oxygen species (ROS) production in human polymorphonuclear neutrophils (PMN). These findings indicate that sword brake fern may prevent atherosclerosis via inhibition of both LDL oxidation and ROS production.     

2008―2021年新疆审定长绒棉品种主要性状演变分析

为全面了解近年新疆育成长绒棉品种的特征特性,对2008―2021年新疆维吾尔自治区主要农作物品种审定委员会审定的43个早中熟长绒棉品种和4个当前待审品种的主要性状演变情况进行分析.结果表明:2012年以来审定品种的铃重较之前明显增加,普遍在3.40 g以上;衣分总体表现较为平稳,皮棉产量受气候环境等因素影响波动较大;纤...     

The siderophore-interacting protein is involved in iron acquisition and virulence of Riemerella anatipestifer strain CH3

Riemerella anatipestifer causes epizootic infectious disease in poultry and serious economic losses especially to the duck industry. However, little is known regarding the molecular basis of its pathogenesis. The ability to acquire iron under low-iron conditions is related to the virulence of a variety of bacterial pathogens. In this study, a sip (Riean_1281) deletion mutant CH3Δsip was constructed and characterized for iron-limited growth, biofilm formation, and pathogenicity to ducklings. Results showed that siderophore-interacting protein (SIP) was involved in iron utilization and the sip deletion significantly reduced biofilm formation and adherence to and invasion of Vero cells. In addition, the sip gene was absent in 1 of 24 (4.17%) virulent strains and 2 of 3 (66.7%) avirulent strains of R. anatipestifer, and the sip gene from six R. anatipestifer strains, which belong to serotypes 1, 2, and 10, respectively, shared 100% amino acid identities to those of R. anatipestifer strains DSM15868 and RA-GD. These results suggested that siderophore-mediated iron acquisition may be an important iron-uptake pathway in R. anatipestifer. Animal experiments indicated that the median lethal dose of the CH3Δsip mutant in ducklings was about 35-fold higher than that of the wild-type CH3 strain. Thus, our results demonstrated that R. anatipestifer SIP was involved in iron acquisition and necessary for its optimal virulence.     

Soil acidification induced by intensive agricultural use depending on climate

Journal of Soils and Sediments - Soil acidification is a major issue in agricultural ecosystems. However, how agricultural land uses shape the soil pH pattern and affect soil acidification on a...     

不同浓度盐胁迫下闽楠和楠木光合生理研究

在3种不同盐胁迫条件下,分析了闽楠和楠木的光合生理特性。结果表明：盐胁迫对闽楠和楠木的净光合速率（Pn）、蒸腾速率（Tr）、气孔导度（Gs）、胞间CO2浓度（Ci）和气孔限制值（Ls）均有明显的抑制作用,且同一处理不同树种间的净光合速率（Pn）、蒸腾速率（Tr）、气孔导度（Gs）、胞间CO2浓度（Ci）和气孔限制值（Ls）存在差异;同一树种在不同处理条件下,净光合速率（Pn）、蒸腾速率（Tr）、气孔导度（Gs）、胞间CO2浓度（Ci）和气孔限制值（Ls）也发生明显变化。     

木材检验技术在木材运输中的应用探讨

文章介绍了木材检验技术在木材运输中的作用与地位,分析了木材运输中常见的木材检验技术误区,阐述了由此引起的责任风险或者造成的危害,并依据现行木材检验标准规定,针对性地提出了规范的木材检验技术操作要领。     

Manipulation of vertical fence wake using passive vortex generators

The effect of streamwise vortices generated from passive vortex generators was investigated to manipulate the separation bubble behind the vertical fence. The experiments were carried out in a circulating water channel and the velocity fields were measured using 2D and stereoscopic PIV method.The distance between the vortex generator and fence and the effect of the Reynolds number were investigated. In addition,the effect of boundary layer thickness was also investigated. The averaged recirculation lengths were compared with that of uncontrolled fence flow. The results showed the oscillatory variation of recirculation region appeared under the existence of vortex generators. The reduction of the separation bubble became larger when the fence was submerged in the thick boundary layer with increasing the distance between the generator and fence. When the boundary layer is thin,vortex generator can only suppress the separation bubble under the specific condition.