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Partial Shade Optimizes Photosynthesis and Growth in Bayberry (Myrica rubra) Trees
Guanghui Zeng,Yanping Guo,Jianxu Xu,Meijun Hu,Jie Zheng,Zhenwang Wu 한국원예학회 2017 Horticulture, Environment, and Biotechnology Vol.58 No.3
This study investigates the effects of radiation heat-load reduction under different shading conditions on thegrowth of three-year-old bayberry (Myrica rubra) trees from 1 July through 31 October 2007 in the Zhejiang Province,a warm subtropical region of China. The trees were grown under direct sunlight (control) and under 25%, 50%, and75% shading conditions using black plastic nets. Stomatal conductance and photosynthesis were greatest under 50%shading, as were plant height and leaf and root dry weights. Twenty-five percent shading did not significantly influenceplant height or root and leaf dry weights, whereas 75% shading resulted in a decrease in root and leaf dry weightswhen compared with the controls. The photochemical efficiency and electron transport of PSII increased under shadedconditions due to an increase in D1 protein. The concentrations of chlorophyll a and b and the total chlorophyllcontent in leaves were increased in plants grown under 25% and 50% shading, but reduced in those grown under75% shading. Under 50% shading, growth and biomass increased due to increased photosynthesis, which resulted fromdecreased photodamage and increased chlorophyll concentration. These data show that 50% shading promotes optimalgrowth in bayberry plants.
Jian Xu,Fei Zhong,Yonghong Zhang,Jianlou Zhang,Shanshan Huo,Hongyu Lin,Liyue Wang,Dan Cui,Xiujin Li 아세아·태평양축산학회 2017 Animal Bioscience Vol.30 No.4
Objective: To generate recombinant Bacillus subtilis (B. subtilis) engineered for expression of porcine β-defensin-2 (pBD-2) and cecropin P1 (CP1) fusion antimicrobial peptide and investigate their anti-bacterial activity in vitro and their growth-promoting and disease resisting activity in vivo. Methods: The pBD-2 and CP1 fused gene was synthesized using the main codons of B. subtilis and inserted into plasmid pMK4 vector to construct their expression vector. The fusion peptide-expressing B. subtilis was constructed by transformation with the vector. The expressed fusion peptide was detected with Western blot. The antimicrobial activity of the expressed fusion peptide and the recovered pBD-2 and CP1 by enterokinase digestion in vitro was analyzed by the bacterial growth-inhibitory activity assay. To analyze the engineered B. subtilis on growth promotion and disease resistance, the weaned piglets were fed with basic diet supplemented with the recombinant B. subtilis. Then the piglets were challenged by enteropathogenic Escherichia coli (E. coli). The weight gain and diarrhea incidence of piglets were measured after challenge. Results: The recombinant B. subtilis engineered for expression of pBD-2/CP1 fusion peptide was successfully constructed using the main codons of the B. subtilis. Both expressed pBD-2/CP1 fusion peptide and their individual peptides recovered from parental fusion peptide by enterokinase digestion possessed the antimicrobial activities to a variety of the bacteria, including gram-negative bacteria (E. coli, Salmonella typhimurium, and Haemophilus parasuis) and gram-positive bacteria (Staphylococcus aureus). Supplementing the engineered B. subtilis to the pig feed could significantly promote the piglet growth and reduced diarrhea incidence of the piglets. Conclusion: The generated B. subtilis strain can efficiently express pBD-2/CP1 fusion antimicrobial peptide, the recovered pBD-2 and CP1 peptides possess potent antimicrobial activities to a variety of bacterial species in vitro. Supplementation of the engineered B. subtilis in pig feed obviously promote piglet growth and resistance to the colibacillosis.
Triaxial Shear Behavior of Basalt Fiber-Reinforced Loess Based on Digital Image Technology
Jian Xu,Zhipeng Wu,Hui Chen,Longtan Shao,Xiangang Zhou,Songhe Wang 대한토목학회 2021 KSCE Journal of Civil Engineering Vol.25 No.10
Engineering construction in loess areas often requires improvement of loess. Basalt fiber-reinforced soil due to complexity of material composition often exhibits poorly predictable mechanical behavior. In this study, digital image technology-based unconsolidated-undrained (UU) triaxial shear tests were carried out on loess samples at three fiber lengths (L) and four fiber contents (η). Results prove the improvement of the shear strength of loess by basalt fiber inclusion, which varies in inverted u-shaped pattern with fiber length or fiber content, with the maximum at η = 0.6%, L = 12 mm. Digital Image Technology was employed to analyze the damage characteristics and strain field of the surface of the sample at different loading time. The volumetric strain of the reinforced sample decreases at higher fiber content or fiber length, from shear contraction to dilatancy. The unreinforced sample exhibits a typical brittle failure mode with visible shear band, while plastic failure for reinforced samples with an overall bulging failure mode. A statistical damage constitutive model of fiber-reinforced loess was established with limited parameters calibrated. The rationality of the model was verified by comparisons of measured and calculated stress-strain data.
Jian Xu,Yewen Cao,Deqiang Wang,Changlei Wu,Guang Yang 한국전자통신연구원 2016 ETRI Journal Vol.38 No.3
Recently, a product-matrix (PM) framework was proposed to construct optimal regenerating codes for homogeneous distributed storage systems (DSSs). In this paper, we propose an extended PM (EPM) framework for coding of heterogeneous DSSs having different repair bandwidths but identical storage capacities. Based on the EPM framework, an explicit construction of minimum remote-repair bandwidth regenerating (MRBR) codes is presented for a specific heterogeneous DSS, where two geographically different datacenters with associated storage nodes are deployed. The data reconstruction and regeneration properties of the MRBR code are proved strictly. For the purpose of demonstration, an example implementation of MRBR code is provided. The presented MRBR code is the first optimal strict-regenerating code for heterogeneous DSSs. In addition, our proposed EPM framework can be applied to homogeneous systems also.
Jian Xu,Liyang Zhou,Ke Hu,Yanfeng Li,Xiangang Zhou,Songhe Wang 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.5
In this study, the influence of wet-dry cycles on the uniaxial compression behavior of fissured loess after vibration was investigated by small shaking table tests, wet-dry tests, and uniaxial compression tests. Results show that the initial elastic modulus and peak strength both decline after wet-dry cycles while the morphology of stress-strain curves shows insignificant changes. Except for samples with a fissure angle α = 45°, where the bimodal stress-strain curves were observed, all show softening trend. The failure mode can be classified into four main types: fracture failure (α = 0° and 15°), slip-fracture coupled failure (α = 45°), slip failure (α = 60°), and compression shear failure (α = 30° and 90°). The failure modes of samples at α = 0°, 15°, 45°, and 60° are independent of wet-dry cycles but strongly depend on fissure angle, while those at the other fissure angles are more susceptible to wet-dry cycles. The uniaxial compressive strength (UCS) of fissured loess samples before vibration are greater than those after vibration. The relationship between UCS and fissure angle before and after vibration show double-valley pattern. A binary medium model for fissured loess considering vibration and wet-dry cycles was constructed, which was verified by test data.
Jian XU,Jaewoo SIM 한국유통과학회 2020 Asian Journal of Business Environment (AJBE) Vol.10 No.4
Purpose: The purpose of this paper is to empirically investigate the relationship between government subsidies and research and development (R&D) investment of animal husbandry companies in China. The moderating effects of firm size, debt ratio, and firm profitability on this relationship are also examined. Research design, data and methodology: The analysis is based on 14 animal husbandry companies listed on the Shanghai and Shenzhen stock exchanges over the period of 2012-2016. Data are obtained from the China Stock Market & Accounting Research (CSMAR) database and the RESSET database, and multiple regression analysis is utilized with the aid of Stata. Results: The empirical results show that government subsidies can promote R&D investment of animal husbandry companies in China. In addition, firm size, debt ratio, and firm profitability have positive moderating effects on the relationship between government subsidies and R&D investment. Conclusions: Based on the results, the paper concludes that government subsidies play an important role in the process of R&D of China’s animal husbandry companies. This paper recommends that managers of animal husbandry companies should enhance the utilization efficiency of government subsidies and put great emphasis on R&D investment. The policymakers should implement more incentives to encourage animal husbandry companies to invest more in R&D.