Weaning methods affect ruminal methanogenic archaea composition and diversity in Holstein calves

The objective of the present study was to examine the effect of different weaning methods on the ruminal methanogenic archaea composition and diversity in Holstein calves.Thirty-six newborn Holstein bull calves were assigned to 1 of 3 treatments:(1)conventional weaning(d 56)and fed a high proportion of solid feed(CWS);(2)conventional weaning(d 56)and fed a high proportion of liquid feed(CWL);(3)early weaning(d 42)and fed with a high proportion of solid feed(EWS).High-throughput sequencing of the methyl coenzyme M reductase(mcr A)gene,which encodes theα-subunit of methyl coenzyme M reductase-the enzyme that catalyzes the final step in methanogenesis was used to determine the composition and diversity of rumen methanogens.No significant difference(P>0.05)was observed for operational taxonomic units(OTUs)or richness indices,but diversity indices increased(P<0.05)for calves fed high dietary solids.Predominant families across the three treatments were Methanobacteriaceae,Thermoplasmataceae and Methanomassiliicoccaceae.Calves in the EWS treatment had a higher(P<0.05)relative abundance of Methanobrevibacter sp.strain AbM4 and Methanosphaera stadtmanae,while calves in the CWL treatment had a higher(P<0.05)abundance of Methanosphaera sp.strain SM9.A positive(P<0.05)relationship was identified between butyrate and Methanobrevibacter sp.strain AbM4.In conclusion,the composition and diversity of methanogens in the rumen of Holstein calves varied under the different weaning methods.This study identified a positive relationship between butyrate and Methanobrevibacter sp.strain AbM4,potentially reflecting correlations between ruminal fermentation variables and methanogenesis function.These in-depth analyses provide further understanding of weaning methods for intensified production systems.

Rock mechanical problems and optimization for the long and deep diversion tunnels at Jinping Ⅱ hydropower station

According to site-specific environments such as high water pressures, high in-situ stresses and strong rockbursts, the design scheme of the long and deep diversion tunnels at Jinping II hydropower station was optimized to ensure construction safety. New drainage tunnels were considered. Furthermore, lining structures and grouting pressures were modified during the excavation of tunnels. The construction scheme was updated dynamically based on the complex geological conditions. For instances, the diversion tunnels were first excavated by drilling and blasting method at the first stage of construction, and then by the combination method of tunnel boring machine （TBM） and drilling and blasting, and finally by drilling and blasting method. Through optimized scheme and updated construction scheme, the excavation of diversion tunnel #1 was successfully completed in June, 2011. This paper summarizes the key issues in rock mechanics associated with the construction of the long and deep diversion tunnels at Jinping II hydropower station. The experiences of design and construction obtained from this project could provide reference to similar projects.

Geometric interpretation of several classical iterative methods for linear system of equations and diverse relaxation parameter of the SOR method

Two kinds of iterative methods are designed to solve the linear system of equations, we obtain a new interpretation in terms of a geometric concept. Therefore, we have a better insight into the essence of the iterative methods and provide a reference for further study and design. Finally, a new iterative method is designed named as the diverse relaxation parameter of the SOR method which, in particular, demonstrates the geometric characteristics. Many examples prove that the method is quite effective.

Penalty model for delay of bidding section construction period in South-to-North Water Diversion Eastern Route Project from perspective of programs

According to the multi-project and program management theory, this paper analyzes the program generation principle and establishes a program based on progress goals. On the basis of the present situation of calculation of penalty for delay of the bidding section construction period with the critical path method, we studied the effects of contractor-induced delay of the bidding section construction period in detail, including the effects on the construction period of the bidding section itself, the earliest start times of the next bidding section and other subsequent bidding sections, and the construction period of the program, and then constructed a penalty model for delay of the bidding section construction period from the perspective of programs. Using the penalty model, we conducted a practical analysis of penalty for delay of the construction period of the Baoying station program in the South-to-North Water Diversion Project. The model can help determine the amount of penalty for delay of the construction period in bidding sections scientifically and reasonably,

Analysis on the Structure of Influencing Factors of Sustainable Supply Chain Implementation of Water Diversion Project

The systematic analysis of the hierarchical relationship among the factors affecting the sustainable supply chain implementation of water diversion projects has theoretical value and practical significance for the sustainable development of large-scale water diversion projects. Through the investigation of relevant literature, books, web pages, materials, and discussions with relevant experts and scholars, a total of 23 factors influencing the sustainable supply chain implementation of water diversion projects were identified. Then using ISM (Interpretative Structural Modeling Method) to analyze the causality of each factor, a multi-level hierarchical structure model was obtained. The results showed that: 1) The surface-level influencing factors of the sustainable supply chain implementation of the water diversion project mainly included 8 factors such as water-saving awareness and water-saving intensity in the diversion area, water quality, water pollution and other disasters, effective incentive mechanisms, etc., and surface-level influencing factors were directly related to the sustainable supply chain implementation of water diversion projects. 2) The indirect influencing factors of the sustainable supply chain of water diversion projects included 12 factors such as the water quality and quantity guarantee rate of the supply chain, the government’s enforcement of laws and regulations, water distribution, ecological compensation, and compensation mechanisms for residents in the water source area. Indirect influencing factor scan acts directly on the direct influencing factors, and intervening in the factors that can be controlled by humans is one of the important ways to improve the sustainable operation of water diversion projects. 3) The fundamental influencing factors for the sustainable supply chain implementation of water diversion projects included three factors: Resettlement policy, government financial support, and sound laws and regulations. Deep influencing factors had multi-channel influence and controllability, and intervening in them was the main means to improve the sustainable operation of water diversion projects.

间作黄芪对当归根际土壤微生物的影响

目的:探讨根际土壤微生物对中药材种植模式的响应方式。方法:以间作黄芪及单作下当归根际土壤为研究对象,基于高通量测序技术,分析土壤微生物在不同季节及种植模式下群落组成及功能的差异。结果:间作下Chao1指数、ACE指数高于单作,变形菌门、放线菌门、酸杆菌门、绿弯菌门和芽单胞菌门为间作下的优势菌门,芽单胞菌门的相对丰度在间作下高于单作。11月间作下γ变形菌纲、7月间作下全噬菌纲的丰度显著高于单作。KEGG功能预测表明,在不同时间及间作下根际土壤细菌与细胞过程、环境信息处理、遗传信息处理、代谢功能下属的23类二级功能基因的相对丰度存在显著差异;参与氮循环的功能基因K00371(narH/narY/nxrB)、(K00374 narI/narV)等OTU数在间作下显著高于单作;不同门、纲在间作下的共生网络比单作下连接紧密且更复杂。结论:当归间作黄芪影响土壤细菌群落组成,增加其丰富度及功能的丰富性,影响土壤氮循环能力,促进土壤微生物间的交互作用。

李园杂草管理方式对土壤细菌群落和生态功能的影响

【目的】分析不同杂草管理方式对位于国家重点生态功能县的李园细菌群落结构和生态功能的影响,为李园土壤健康管理提供参考。【方法】以自然生草、人工生草、除草剂除草的李园和邻近天然槲栎次生林土壤为研究对象,提取土壤细菌DNA,对其ITS基因进行扩增,采用高通量测序和功能预测的方法研究细菌的多样性、群落结构及生态功能。【结果】不同处理OTU数量为2012~3522,细菌种类33门、108纲、242目、383科、667属。绿弯菌门、放线菌门、变形菌门和酸杆菌门为主要门类,在各处理中4个门的总丰度达到80%以上。多样性分析显示,天然林Ace和Chao指数显著低于李园的3个处理。群落组成和差异分析显示,天然林土壤酸杆菌优势比较大,病害细菌少,并有少量的有益细菌蛭弧菌;李园的鞘脂单胞菌相关病害的风险大,生草可在一定程度上提高芽孢杆菌等有益细菌的丰度,尤其自然生草比较明显。人工生草还有利于提高李园细菌的多样性,尤其是芽单胞菌的富集比较明显。使用除草剂的李园则主要富集了绿弯菌门的种类,而降低了苔藓杆菌的丰度。功能预测分析显示,土壤细菌新陈代谢最活跃,主要包括碳水化合物代谢和氨基酸代谢等,涉及化能异养、纤维素分解、固氮作用等功能。与其他处理比较,人工生草李园土壤硝酸还原功能较强、天然林土壤的木质素分解功能较强、除草剂处理的李园土壤甲基营养功能较强。【结论】天然林Ace和Chao指数显著低于李园,表现为土壤酸杆菌优势明显。不同杂草管理方式对李园土壤细菌群落结构和功能的影响较大,生草有利于李园有益细菌群落的建立。

基于模糊综合分析法的引调水工程水质响应关系分析

为提升引调水工程的环境改善效果,须对水体的自身连通水平、水质现状、水环境主要影响因子进行分析。以太湖流域跃进联圩为研究对象,利用图论连通度理论对研究区域静态基流连通性进行评价,探索圩内水系连通性的空间差异及变化特性。同时,开展短期引调水实验,结合模糊综合分析法评价引调水带来的圩内水质变化情况及规律,研究圩内水环境和水系连通性的响应关系。结果表明,模糊综合评价法在引调水环境改善分析中具有适用性,可实现对圩内各监测点位水质变化的全面分析;水体流动性是影响圩区内水质的重要环境因素,高锰酸盐指数是导致圩内水质恶化的主要影响因子。引调水工程对圩区水环境具有一定的持续改善性作用,但对基流连通性较差的区域,改善效果有限。

知识复杂性的测度方法综述与比较

[研究目的]复杂知识是突破关键核心技术的基础支撑,也是企业或区域建立竞争优势的关键要素。该文旨在全面把握知识复杂性测度方法的研究现状与前沿进展,为知识复杂性的深入研究提供测度理论基础。[研究方法]通过梳理国内外知识复杂性研究的相关文献,详细介绍三种主要的知识复杂性测度方法的核心思想、理论基础和计算过程,并进一步对比分析不同方法的适用层次和优缺点,最后提出未来研究方向。[研究结论]反射法主要基于知识的空间分布异质性间接衡量知识复杂性,虽然原理简单且操作相对容易,但无法揭示知识复杂性的本质特征;元素依赖性指数利用知识组合频次衡量知识元素之间的相互依赖程度,进而反映知识复杂性,忽视了其他影响知识组合的因素;结构多样性指数通过知识组合网络拓扑结构的多样性反映知识复杂性,综合考虑多个网络结构指标,并经过大量数值模拟检验,但存在估计结果不稳定、仅适用于二值网络等问题。

24158例人乳头瘤病毒基因检测结果分析

目的:回顾性分析广西壮族自治区南宁市女性人乳头瘤病毒(humanpapillomavirus,HPV)的感染情况、基因分型及年龄的分布特征,为宫颈癌的早期筛查、诊断和治疗提供参考依据。方法:收集2020年4月-2022年12月在广西南宁市第二人民医院妇科门诊、妇科住院部及体检中心就诊的女性宫颈脱落细胞标本24158例,应用聚合酶链式反应和导流杂交法检测样本中人乳头瘤病毒的21种基因分型,分析不同年龄段HPV的感染状况、高危型和低危型分布情况、感染型别的情况。结果:在24158例标本中,4745例检查出感染HPV,感染率为19.64%;检测出HPV基因型别6546例,其中高危型别5231例,在总阳性例数中的比例为79.91%,低危型别1315例,所占的比例为20.09%,单一型别感染3527例,双重型别感染865例,三重及以上型别感染353例。其中居前五位的高危型基因型别依次为HPV53型、HPV59型、HPV18型、HPV52型、HPV56型,居前三位的低危型基因型别依次为HPV11、HPV42型、CP8304型。其中≤20岁患者占38.43%(362/942),41~50岁患者占14.44%(735/5091)。结论:24158例样本中,HPV感染率达19.64%,高危型感染以HPV53型、HPV59型、HPV18型、HPV52型、HPV56型为主,低危型感染以HPV11、HPV42、CP8304型为主,高危型别的检出率均高于低危型别。因此定期对青年和中老年女性群体HPV筛查,科普HPV知识,提高多价HPV疫苗的人群接种率,对于预防HPV感染及早期诊断、临床治疗具有重大意义。

岩溶隧洞突涌水灾害风险评价研究

受复杂地质条件的影响,岩溶隧洞在施工过程中极易发生突涌水灾害。为准确评估岩溶隧洞突涌水风险等级,将结构方程模型(SEM)与改进的模糊综合评价法(FCEM)相结合,构建岩溶隧洞突涌水风险评价模型。从地形地貌、气象水文、地层因素、地质构造、岩溶水文地质、施工因素6个方面深入研究;利用SEM确定各指标标准化路径系数并求得其权重,运用改进FCEM法对岩溶隧洞突涌水风险等级进行评价;以滇中引水工程昆呈隧洞为应用实例,利用Crystal Ball软件验证模型的有效性。结果表明:昆呈隧洞有90%的几率处于52~73分值区间范围内(Ⅲ级风险),与现场实际情况一致,表明基于SEM-改进FCEM法构建的岩溶隧洞突涌水风险评价模型具有一定的适用性;其中岩溶水文地质、地质构造、气象水文是该隧洞的主要影响因素,施工中应加强对这几方面的监控和量测,避免发生突涌水灾害。研究成果可为类似岩溶隧洞工程提供参考。

综述杂豆酚类化合物多样性的影响因素

杂豆酚类化合物种类繁多,并影响杂豆的外观、感官特征及营养特性。杂豆酚类化合物多样性是杂豆营养特性研究的重点。本文总结杂豆酚类化合物多样性的影响因素,发现合理的提取与分析方法有利于酚类化合物提取的完整性以及表征的正确性。在此基础上,指出种属与产地、生长与贮藏及加工过程影响杂豆酚类化合物的合成、溶出与释放,并促使酚类化合物多样性的形成。最后介绍杂豆酚类化合物多样性的代谢组学技术在杂豆多样性研究方面的贡献与优势,提出今后工作的重点与挑战,以期为杂豆酚类化合物的变化机制、加工利用及育种等提供参考。

Diverse AdaBoost-SVM分类方法及其在航空发动机故障诊断中的应用

提出采用考虑到精度/差异权衡的SVM作为弱分类器的一种新的组合分类诊断方法——DiverseAdaBoost-SVM。该方法通过在一组具有适当精度的弱分类器中进一步选择具有较大差异性的弱分类器,对这些具有较大差异性的弱分类器进行组合,从而较好解决AdaBoost算法中存在的精度/差异权衡的难题;同时该方法也较好地解决了现有的AdaBoost方法存在的弱分类器本身参数选取困难问题及训练轮数T的合理选取问题。通过对基准数据库的测试及航空发动机故障样本的诊断,结果表明和其他方法相比,DiverseAdaBoost-SVM方法具有更好的泛化性能,更适合对分散程度较大、聚类性较差的航空发动机故障样本进行分类,也更适合对非对称故障样本集进行分类。

高海拔季节冻土区完全融化期土壤水分特征曲线适用性

以怒江源区那曲流域为例,基于4个试验场完全融化期(6—9月)的土壤体积含水量(0.15~0.51 cm^(3)/cm^(3))和土壤基质势数据(0~200 kPa)实测数据,选择Van Genuchten(VG)、Brooks-Corey(BC)和Campbell 3个模型进行拟合,以均方根误差ERMS和决定系数R2为评价指标,分析3个模型对高海拔季节冻土区不同土层和不同土壤质地的适用性。结果表明:从整体上看,VG模型(平均R2为0.992,平均ERMS为0.006 cm^(3)/cm^(3))的拟合效果优于BC模型(平均R2为0.972,平均ERMS为0.019 cm^(3)/cm/3)和Campbell模型(平均R2为0.984,平均ERMS为0.014 cm^(3)/cm^(3));但是在不同土层和不同土壤质地情况下模型的适用性有所区别,VG模型更适用于壤土和壤质砂土(平均R2为0.987,平均ERMS为0.008 cm^(3)/cm^(3))以及土壤深层(10~35 cm土层,平均R2为0.990,平均ERMS为0.007 cm^(3)/cm^(3)),Campbell模型更适用于砂质壤土(平均R2为0.985,平均ERMS为0.009 cm^(3)/cm^(3))以及土壤表层(5 cm土层,平均R2为0.993,平均ERMS为0.006 cm^(3)/cm^(3)),BC模型在不同条件下都不是最优模型;参数θr取值大小会显著影响土壤水分特征曲线的形状。本研究可为深入研究高海拔季节冻土区的土壤水分运动特性以及中华水塔区的水源涵养作用提供支持。

基于组合赋权-TOPSIS法的引江济淮工程河南受水区节水水平评价

【目的】评价引江济淮工程河南受水区现状节水水平。【方法】从综合、农业、工业、生活、生态环境5个方面选取11项用水指标建立引江济淮工程河南受水区节水水平评价指标体系,构建基于AHP-CRITIC法组合权重的TOPSIS模型,对受水区2020年节水水平进行综合评价。【结果】受水区9个县区中,评价分级为Ⅰ级的有1个(永城市),Ⅱ级5个(梁园区、鹿邑县、睢阳区、柘城县、夏邑县),Ⅲ级3个(郸城县、淮阳区、太康县)。节水水平Ⅱ级(较高)以上的县区占比为66.7%,受水区整体节水水平较高。万元GDP用水量、节水灌溉率、城镇人均生活用水量、城镇公共供水管网漏损率、再生水利用率是制约受水区节水水平的主要影响因素。评价结果与受水区实际情况基本相符。【结论】基于AHP-CRITIC组合赋权的TOPSIS评价方法适用于评价引江济淮工程河南受水区现状节水水平,评价结果与区域实际情况相符,可为水资源优化调配提供参考。

调水工程建设期安全-进度-投资系统风险分析——以引江济淮工程(河南段)为例

以引江济淮工程(河南段)为例,在确定安全-进度-投资系统风险评价指标体系的基础上,基于层次分析-模糊综合评价方法分析安全、进度、投资的单项风险;在考虑工程建设期安全、进度、投资的相互影响后,基于改进的综合风险评价方法分析安全-进度-投资系统风险。结果表明:当分析单项风险时,安全、进度和投资风险的评价结果均为一般风险;当分析系统风险时,得到安全风险>进度风险>投资风险;进一步分析指标体系中的准则层和指标层,安全风险的现场风险中施工技术方案风险排序第一,是后续风险管控的重点。本研究为提高工程建设期安全-进度-投资系统风险的可靠性、降低风险事件的发生提出了理论和技术参考。

基于响应面法的泵站导流墩开孔参数优化

针对扩建泵站工程进水建筑物内存在的偏流、漩涡等不良流态,工程往往采取布置导流墩的方法来优化流态,但其结构参数通常根据经验进行调整,难以达到最优效果。为了确定导流墩开孔的最佳结构参数,研究将导流墩的开孔长度、宽度、高度和间距作为设计变量,基于中心组合设计法进行试验方案设计,以轴向流速均匀度作为评价指标,构建响应面模型进行优化分析,确定了导流墩开孔的最佳参数组合。在最佳参数组合下进行数值模拟,发现实际值与响应面模型预测值误差仅为0.33%,轴向流速均匀度相较于原方案提升了11.17%,显著改善了前池流态。研究结果表明建立的响应面模型能够反应评价指标和设计变量的关系,并且可以将该方法应用到整流措施的结构参数优化中。

频控阵雷达对雷达侦察测向的欺骗机理研究

对地攻击任务中需要根据事先获得的威胁源情报数据借助战术任务规划系统制定打击计划并下发给攻击机。无源雷达侦察测向系统通过对接收信号进行处理,可以解算出威胁源位置信息并提供给任务规划系统。当敌方雷达为频控阵体制而非相控阵体制时,由于频控阵雷达波束的弯曲特性,会对无源测向系统产生欺骗。本文在分析频控阵雷达基本结构的基础上,对比相控阵与频控阵等相位面特性,以干涉仪测向系统为例研究频控阵雷达对比相法测向的欺骗效果。几种非线性FDA阵列的欺骗仿真结果表明,log-FDA的虚拟发射机交点坐标偏离量大于sin-FDA。当干涉仪x轴坐标x_(G)=300 km时,虚拟发射机交点坐标随着干涉仪y轴坐标y_(G)的增加而逐渐逼近FDA阵列实际位置,交点偏移量log-FDA>sin-FDA>reciprocal-FDA。