Tree structure and diversity shape the biomass of primary temperate mountain forests

Primary forests are spatially diverse terrestrial ecosystems with unique characteristics,being naturally regenerative and heterogeneous,which supports the stability of their carbon storage through the accumulation of live and dead biomass.Yet,little is known about the interactions between biomass stocks,tree genus diversity and structure across a temperate montane primary forest.Here,we investigated the relationship between tree structure(variability in basal area and tree size),genus-level diversity(abundance,tree diversity)and biomass stocks in temperate primary mountain forests across Central and Eastern Europe.We used inventory data from726 permanent sample plots from mixed beech and spruce across the Carpathian Mountains.We used nonlinear regression to analyse the spatial variability in forest biomass,structure,and genus-level diversity and how they interact with plot-level tree age,disturbances,temperature and altitude.We found that the combined effects of genus and structural indices were important for addressing the variability in biomass across different spatial scales.Local processes in disturbance regimes and uneven tree age support forest hete rogeneity and the accumulation of live and dead biomass through the natural regeneration,growth and decay of the forest ecosystem.Structural complexities in basal area index,supporte d by genus-level abundance,positively influence total biomass stocks,which was modulated by tree age and disturbances.Spruce forests showed higher tree density and basal area than mixed beech forests,though mixed beech still contributes significantly to biomass across landscapes.Forest heterogeneity was strongly influenced by complexities in forest composition(tree genus diversity,structure).We addressed the importance of primary forests as stable carbon stores,achieved through structure and diversity.Safeguarding such ecosystems is critical for ensuring the stability of the primary forest,carbon store and biodiversity into the future.

Primary Succession of Algal Community Structure in Desert Soil

The microbiotic crust study is among new focuses in investigating on the desertification control. Based on determination of algal crusts with different successive ages (4-, 8-, 17-, 34-, 42-year-old) and unconsolidated sand in the desert area, species composition and clustering analyses were carried out in this study. Results on successional orientation revealed that (1) the abundance of Cyanophyta, specially of Scytonema javanicum gradually decreased; (2) the abundance of Chlorophyta, Bacillariophyta and a species of Cyanophyta, Phormidium tenue increased; (3) the biodiversity increased gradually with the community succession; and (4) biomass of microalgae increased at the early stage, but decreased at the later stage due to the abundance of lichens and mosses. But, the speed of natural succession was so slow that the community-building species was still the first dominant species after 42 years, except that its dominant degree decreased just slightly. However, successive speed and trend were affected by water, vegetation coverage, terrain, time and soil physico-chemical properties as well, especially Mn content in the soil appeared to have a threshold effect.

Effects of melt treatment temperature and isothermal holding parameter on water-quenched microstructures of A356 aluminum alloy semisolid slurry

The semisolid slurry of the A356 aluminum alloy was prepared by self-inoculation method(SIM),the effects of melt treatment temperatures and isothermal holding parameters on water-quenched microstructures of A356 aluminum alloy semisolid slurry were investigated,and the solidification behavior of the remaining liquid phase(secondary solidification)was analyzed.The results indicate that the melt treatment temperature has significant effects on the final semisolid microstructures.The semisolid slurry which is suitable for the rheological forming can be produced when the melt treatment temperature is between 680 and 690°C.During the isothermal holding process,the growth rate of the primary particles conforms to the dynamic equation of Dt 3-Do3=Kt,and the coarsening rate of the primary particles is the fastest when the isothermal holding temperature is 600°C.Additionally,the isothermal holding time also has obvious effect on the secondary solidification microstructures.The secondary particles are the smallest and roundest when the isothermal holding time is 3 min.The amount of the secondary particles gradually increases with the increase of isothermal holding temperature,and the eutectic reaction therefore is confined into small intergranular areas,contributing to the compactness of the final solidified eutectic structures.

Purification and Primary Structure Determination of a Novel Polypeptide Isolated from Mistletoe Viscum coloratum

A novel polypeptide was isolated from mistletoe Viscum coloratum. The primary structure of the polypeptide named viscotoxin B2 was determined to be KSCCKNTTGRNIYNT CRFAGGSRERCAKLSGCKIISASTCPSDYPK by Edman degradation. Viscotoxin B2 shared high sequence homology with viscotoxins isolated from Viscum album. Pharmacological experiments showed that viscotoxin B2 had distinct cytotoxic activity on tumor cells. Viscotoxin B2 could be used as a leading compound in cancer therapy.

Exploring the complex structural evolution of global primary product trade network

The production and trade of primary products had a growing impact on the economic security of all countries and regions,and the strategic position of these products in the global trade network was becoming increasingly prominent.Based on complex network theory,this paper explored the spatial pattern and complex structural evolution of the global primary product trade network(GPPTN)during 1985-2015 by using index methods,such as centrality,Sankey diagram,and structure entropy,focusing on the diversified spatial structure of China’s import and export markets for primary products(with exceptions of Taiwan of China,Hong Kong of China,and Macao of China due to a lack of data)and their geographical implications for China’s energy security.The research offered the following key findings.The GPPTN showed an obvious spatial heterogeneity pattern,and the area of import consumption was more concentrated;however,the overall trend was decentralized.The trade center of gravity shifted eastwards and reflected the rise of emerging markets.The overall flow of the GPPTN was from west to east and from south to north.In terms of the community detection of the GPPTN,North America,Europe,and Asia increasingly presented an unbalanced“tripartite confrontation”.China’s exports of primary products were mainly concentrated in the Association of Southeast Asian Nations(ASEAN)and other peripheral regions of Asia,and its imports undergone a major transformation,gradually expanding from the peripheral regions of Asia to Africa,the Middle East,Latin America,and other parts of the world.Energy fuels also became the largest imported primary products.Based on the changing trend of structural entropy and main market share,the analysis showed that the stable supply of China’s energy diversification was gradually realized.In particular,the cooperation dividend proposed by the Belt and Road initiative became an important turning point and a strong support for the expansion of China’s energy market diversification pattern and guarantee of energy security.

Effect of RE Oxide on Impact Toughness and Primary Structure of Surfacing Metal

The effect of rare earth(RE) oxide on impact toughness and primary structure of surfacing metal was investigated . The results show that the impact toughness of surfacing metal containing RE oxide can be increased by 50 %. The primary structure can be refined and its shape changed from columnar crystals to equiaxed ones.

Cubic Mesoporous Aluminosilicate with Primary Structure Units of Zeolite Beta in the Pore Wall

Mesoporous aluminosilicate with cubic ordered structure was synthesized by two-step crystallization, which showed stronger acid sites and more effective activity for catalytic alkylation of 2, 4-ditert-butylphenol with tert-butanol than conventional H-AlMCM-48 materials.

Model of Primary Austenite Dendrite Structure in Hypoeutectic Cast Iron

The solidification of primary austenite in hypocutcctic gray cast iron was studied by stepped grinding and quantitative metallography.The dendrite structure of primary austenite can be described by three models:typical dendrite crystal model,metamorphic dendrite crystal model and network dendrite crystal model.The dendrite crystals formed according to 3rd model is much more than those formed according to other models in this experiment.The primary austenites are connected each other,and the primary stems of austenite could be regarded as secondary arms and vice versa.

A Breakthrough of Primary Structure in Indeterminate Analysi--Irregular Force Method and Irregular Displacement Method

As the strict limitation of primary structure in traditional force method and displacement method in indeterminate analysis may lead to complicated high-order linear equations, a breakthrough of the limitation, i.e., the application of irregular force method and irregular displacement method, would be introduced in this paper to ease the difficulty of hand computations. By using hyperstatic primary structures and partly chained primary structures, the primary structures of force method and displacement method are reformed, and the order of the system is decreased. The technique is explained through examples. The significance of the new method is summarized.

A STUDY OF THE STRUCTURE AND THE EXPRESSION OF PROTOONCOGENES IN HUMAN PRIMARY GASTRIC CANCER

The allelic distribution of EcoRI and BamHI fragments of ras family genes between the human primary gastric cancer tissues and the corresponding adjacent normal tissues did not show any differences. Three genotypes of BamHI restriction fragments length polymorphism of c-H-ras were revealed. No significant differences in the RFLPs were observed between normal individuals and gastric cancer patients. Four protooncogenes, c-H-ras, N-ras, c-myc and c-fos, were found to be transcriptionally active in the gastric cancer tissues in some cases examined. The comparison of the expression of these oncogenes between the malignant tissues and the corresponding normal tissues showed differential patterns. The expression of c-H-ras at cellular level was detected with in situ hybridization. The enhanced expression of c-H-ras in the gastric cancer cells was demonstrated, but the degree of the expession among the cancer cells was shown to be heterogeneous. In addition, the enhanced expression of c-H-ras was seen in the inflammatory cells.

Compound heterozygous mutations in CYP1B1 gene leads to severe primary congenital glaucoma phenotype

AIM: To identify the novel mutation alleles in the CYP1B1 gene of primary congenital glaucoma(PCG) patients at Shandong Province of China, and investigate their correlation with glaucomatous features.METHODS: The DNA from the peripheral blood of 13 congenital glaucoma patients and 50 ethnically matched healthy controls from the affiliated hospital of Qingdao University were extracted. The coding region of the CYP1B1 gene was amplified by PCR and direct DNA sequencing was performed. Disease causing-variants were analyzed by comparing the sequences and the structures of wild type and mutant CYP1B1 proteins by PyMOL software.RESULTS: Two missense mutations, including A330 F caused by c.988 G>T&c.989 C>T, and R390H caused by c.1169 G>A, were identified in one of the 13 PCG patients analyzed in our study. A330F mutation was observed to be novel in the Chinese Han population, which dramatically altered the protein structure of CYP1B1 gene, including the changes in the ligand-binding pocket. Furthermore, R390H mutation caused the changes in heme-protein binding site of this gene. In addition, the clinical phenotype displayed by PCG patient with these mutations was more pronounced than other PCG patients without these mutations. Multiple surgeries and combined drug treatment were not effective in reducing the elevated intraocular pressure in this patient.CONCLUSION: A novel A330F mutation is identified in the CYP1B1 gene of Chinese PCG patient. Moreover, in combination with other mutation R390H, this PCG patient shows significant difference in the CYP1B1 protein structure, which may specifically contribute to severe glaucomatous phenotype.

Solidification behavior and rheo-diecasting microstructure of A356 aluminum alloy prepared by self-inoculation method

Semisolid slurry of A356 aluminum alloy was prepared by self-inoculation method, and the microstructure and solidification behavior during rheo-diecasting process were investigated. The results indicate that the semisolid slurry of A356 aluminum alloy can be prepared by self-inoculation method at 600℃. Primary a-AI particles with fine and spherical morphologies are uniformly distributed when the isothermal holding time of slurry is 3 min. Liquid phase segregation occurs during rheo-diecasting process of semisolid slurry and the primary particles （α1） show obvious plastic deformation in the area of high stress and low cooling rate. A small amount of dendrites resulting from the relatively low temperature of the shot chamber at the initial stage of secondary solidification are fragmented as they pass through the in-gate during the mould filling process. The amount of dendrite fragments decreases with the increase of filling distance. During the solidification process of the remaining liquid, the nucleation rate of secondary particles （α2） increases with the increase of cooling rate, and the content of Si in secondary particles （α2） are larger than primary particles （α1）. With the increase of cooling rate, the content of Si in secondary particles （α2） gradually increases. The morphologies of eutectic Si in different parts of die casting are noticeably different. The low cooling rate in the first filling positions leads to coarse eutectic structures, while the high cooling rate in the post filling positions promotes small and compact eutectic structures.

Effects of Hypoxia on the Growth and Development of the Fetal Ovine Hepatocytes in Primary Culture

Objective To investigate the development and characterizations of the hepatocytes isolated from fetal ovine and to determine the effect of hypoxia on their growth and metabolism.Methods Fresh hepatocytes were isolated from the liver of fetal ovine at late gestation, cultured in specific media, and exposed to normoxia(21% O2) or hypoxia(2% O2).The cellular characteristics and population purity were identified by immunocytochemistry and flow cytometry(FCM).The effects of hypoxia on cell cycle and apoptosis of the hepatocytes were evaluated by FCM, whereas the cellular ultrastructure changes were examined with a transmission electron microscope.Results The cell purity of hepatocytes was over 95%.Under hypoxia exposure, the hepatocytes showed a gradual increase in proportion at the S phase and in proliferative index, followed with a compatible increase in apoptosis and progressively decreased cell viability.Additionally, the organelles of the hepatocytes demonstrated dramatic changes, including swelling of mitochondria, disorder in cristae arrangement, expansion of endoplasmic reticulum, and a large number of circular lipid droplets emerging in the cytoplasm.Conclusion Fetal ovine hepatocytes could be primarily cultured in a short-term culture system with a high purity of over 95% and with their preserved original characteristics.Hypoxia could induce changes in ultrastructural and inhibit the proliferation of cultured fetal ovine hepatocytes through apoptotic mechanisms.

Comparative Analysis of Structure and Sequences of <i>Oryza sativa</i>Superoxide Dismutase

One of the major classes of antioxidant enzymes, which protect the cellular and subcellular components against harmful reactive oxygen species (ROS), is superoxide dismutase (SOD). SODs play pivotal role in scavenging highly reactive free oxygen radicals and protecting cells from toxic effects. In Oryza sativa three types of SODs are available based on their metal content viz. Cu-Zn SOD, Mn SOD and Fe SOD. In the present study attempts were made to critically assess the structure and phylogenetic relationship among Oryza sativa SODs. The sequence similarity search using local BLAST shows that Mn SODs and Fe SODs have greater degree of similarity compared with that of Cu-Zn SODs. The multiple alignment reveals that seven amino acids were found to be totally conserved. The secondary structure shows that Mn SODs and Fe SODs have similar helixes, sheets, turns and coils compared with that of Cu-Zn SODs. The comparative analysis also displayed greater resemblance in primary, secondary and tertiary structures of Fe SODs and Mn SODs. Comparison between the structure and sequence analysis reveals that Mn SOD and Fe SOD are found to be closely related whereas Cu-Zn SOD evolves independently.

Study of quantum well mixing induced by impurity-free vacancy in the primary epitaxial wafers of a 915 nm semiconductor laser

Output power and reliability are the most important characteristic parameters of semiconductor lasers.However,catas-trophic optical damage(COD),which usually occurs on the cavity surface,will seriously damage the further improvement of the output power and affect the reliability.To improve the anti-optical disaster ability of the cavity surface,a non-absorption window(NAW)is adopted for the 915 nm InGaAsP/GaAsP single-quantum well semiconductor laser using quantum well mix-ing(QWI)induced by impurity-free vacancy.Both the principle and the process of point defect diffusion are described in detail in this paper.We also studied the effects of annealing temperature,annealing time,and the thickness of SiO_(2) film on the quan-tum well mixing in a semiconductor laser with a primary epitaxial structure,which is distinct from the previous structures.We found that when compared with the complete epitaxial structure,the blue shift of the semiconductor laser with the primary epi-taxial structure is larger under the same conditions.To obtain the appropriate blue shift window,the primary epitaxial struc-ture can use a lower annealing temperature and shorter annealing time.In addition,the process is less expensive.We also pro-vide references for upcoming device fabrication.

Research on the Construction of Pharmacy Organization and the Development of Pharmaceutical Services in China’s Primary Medical and Health Institutions—Based on the Survey of 5 Provinces

Objective To explore the current situation and problems of the pharmacy organization and pharmaceutical services in primary medical and health institutions so as to provide a reference for improving relevant policies.Methods Multi-stage stratified random sampling was used to collect questionnaires from primary medical and health institutions in 5 provinces,and 102 questionnaires were distributed.Then Excel 2016 and IBM SPSS 21.0 software were applied for descriptive statistical analysis,chi-square test and multiple response analysis.Results and Conclusion A total of 92 primary medical and health institutions participated in the survey,and 92 valid questionnaires were recovered.The survey shows that 54.1%of the institutions have established more than 8 pharmaceutical administration regulations.63.5%and 31.8%of the institutions have formulated pharmaceutical administration and pharmacotherapy team charters(or management systems).29.7%of institutions have pharmacy personnel in accordance with relevant regulations.The higher proportion of pharmacy services are prescription review and adjustment,medication guidance,collecting and reporting adverse reactions,medication errors and medication hazard information.Primary medical and health institutions still need to further improve their pharmaceutical administration system,organizational structure,pharmacy professional training and clinical pharmacy service.

由规模化到精准化:国家中小学智慧教育平台教师研修的差异化需求及优化策略研究

立足常态化的新发展阶段,国家智慧教育平台教师寒暑假研修如何从规模化走向差异化、精准化,“按需施训”尤为关键。研究以基础教育阶段参训教师的9.06万条、149万余字反馈文本为研究对象,综合运用结构主题模型(STM)及重要性-绩效分析法(IPA),构建了国家中小学智慧教育平台教师研修需求框架,并深入分析其差异、明确基于需求要素的优化方向。研究发现:参训教师需求包含个体发展和系统环境两个层面的五类需求,且均存在显著的区域及城乡差异,针对时间安排及学时认定等研修机制需求仍须优化改进。研究为教师寒暑假研修精准化、差异化发展提供实证依据与决策支持,为优化研修服务提供策略建议。

何以补齐中小学体育教师资源短板?——基于深化体教融合典型实践的多案例分析

基于5个典型案例,依据资源依赖理论聚焦体育教师资源、组织结构关系和效能提升3个主题及其相互内在关联因素,归纳出市场运行机制、校际合作机制、政社合作机制、政策支持机制和行动补给机制5种补齐普通中小学体育教师资源短板的适配机制。体育、教育等行政组织及普通中小学、体校、青少年体育俱乐部等组织形成恰适性治理逻辑、网络化治理格局和互补型治理方式的组织结构关系,实现对国家深化体教融合等顶层设计的政策创新、满足参与行动组织资源诉求和学校体育教育资源再生的目标。以此为导向构建更具包容性的补齐中小学体育教师资源短板的理论模型,以及多种机制共存的学校体育资源供给路径。

教科版小学科学新教材的理念与特色

教科版小学科学新教材的编写原则是:坚持素养导向,突显科学思维,加强进阶贯通,丰富中国元素,重视地区普适。新教材继承了老教材大单元结构特点,通过强化情境设计等举措加强了单元内课文间的联系。各单元由“单元首页—单元内容—单元小结—科学阅读”四大部分构成,其中“单元小结”显性化地凝练出学科核心概念和跨学科概念。每一课由聚焦、探索、研讨、拓展四大板块构成,对应工程技术实践为主的课文则为明确任务、设计方案、实施方案、评价改进等板块。与教材配套的教参也进行了大幅度修订。使用新教材应注意充分利用教参功能,全面理解大单元结构,灵活应用四大板块,在理解教材的基础上鼓励因地制宜。

基于滑模变结构的风电机组一次调频算法研究

针对并网风电场中,经典一次调频控制方法存在抗干扰能力弱、机组易脱网的问题,提出一种基于滑模变结构的风电机组一次调频控制算法。首先,在永磁同步风电机组工作原理的基础上,建立含有大电网的风电机组模型。其次,为了解决传统比例积分微分(proportional integral differential,PID)控制下抗干扰能力弱的问题、引入经典滑模变结构控制器。然后,针对经典滑模变结构控制器导致执行机构存在抖振较多的缺点,提出一种基于sigmoid函数趋近率的滑模变结构一次调频控制算法。最后,通过MATLAB/Simulink对风电机组一次调频进行建模仿真,并与经典控制算法相比,验证了所提算法的可行性,在风速波动和电网故障的环境下,滑模变结构一次调频控制算法更具有效性。