Tree allometry responses to competition and complementarity in mixed-species plantations of Betula alnoides

Tree allometry plays a crucial role in tree survival,stability,and timber quantity and quality of mixed-species plantations.However,the responses of tree allometry to resource utilisation within the framework of interspecific competition and complementarity remain poorly understood.Taking into consideration strong-and weakspace competition(SC and WC),as well as N_(2)-fixing and non-N_(2)-fixing tree species(FN and nFN),a mixedspecies planting trial was conducted for Betula alnoides,a pioneer tree species,which was separately mixed with Acacia melanoxylon(SC+FN),Erythrophleum fordii(WC+FN),Eucalyptus cloeziana(SC+nFN)and Pinus kesiya var.langbianensis(WC+nFN)in southern China.Six years after planting,tree growth,total nitrogen(N)and carbon(C)contents,and the natural abundances of^(15)N and^(13)C in the leaves were measured for each species,and the mycorrhizal colonisation rates of B.alnoides were investigated under each treatment.Allometric variations and their relationships with space competition and nutrient-related factors were analyzed.The results showed a consistent effect of space competition on the height-diameter relationship of B.alnoides in mixtures with FN or nFN.The tree height growth of B.alnoides was significantly promoted under high space competition,and growth in diameter at breast height(DBH),tree height and crown size were all expedited in mixtures with FN.The symbiotic relationship between ectomycorrhizal fungi and B.alnoides was significantly influenced by both space competition and N_(2) fixation by the accompanying tree species,whereas such significant effects were absent for arbuscular mycorrhizal fungi.Furthermore,high space competition significantly decreased the water use efficiency(WUE)of B.alnoides,and its N use efficiency(NUE)was much lower in the FN mixtures.Structural equation modeling further demonstrated that the stem allometry of B.alnoides was affected by its NUE and WUE via changes in its height growth,and crown allometry was influenced by the mycorrhizal symbiotic relationship.Our findings provide new insights into the mechanisms driving tree allometric responses to above-and belowground resource competition and complementarity in mixed-species plantations,which are instructive for the establishment of mixed-species plantations.

Long Run Relationships, Vertical Integration and International Competition： Can They Contribute to Explaining Regional Construction Cost Differences？

The existence of opportunistic behavior by contractors or sub-contractors in the bidding process encouraged by the governance structure of construction companies as well as the kind of relationship that exist between contractors and clients is thought to have some bearing on the rising construction cost observed in some regions of Sweden. Three hypotheses that are intended to test the impact that long run relationship between contractors and developers, vertically integrated firms, and the increase of international competition could have on the construction cost increase levels were tested on a predetermined number of projects from six cities in different regions. The semi-structured survey produces inconclusive results. Long run and collaborative relationship was prevalent in small region though respondents in this region did not draw strong connection between construction cost increase levels and the kind of observed relationship. In Stockholm region, short-term relationship was mostly prevalent. Vertical integration and foreign competition impacts on construction costs were not significant in either region.

Competitive Relationships and Yield Advantage of Intercropping Faba Bean with Sugar Beet under Bio-Organic Additives and Mineral Nitrogen Fertilizer Rates

A field experiment was conducted at El-Serw Agricultural Research Station, Damietta Governorate, Egypt during 2016/2017 and 2017/2018 seasons to reduce mineral N inputs of sugar beet with increased land use efficiency and profitability under intercropping conditions. Seven treatments included five treatments (90 kg nitrogen “N” + 30 m3 farm yard manure “FYM”/fad, 80 kg N +30 m3 FYM/fad, 70 kg N +30 m3 FYM/fad and 400 g of Cerealine + 30 m3 FYM/fad for intercropping faba bean cultivar Spanish with sugar beet cultivar Gloria) and two treatments (90 and 20 kg N/fad for solid culture of sugar beet and faba bean, respectively, as recommended mineral N fertilizer rate) were compared in a randomized complete block design with three replications. Solid culture of sugar beet with the application of recommended rate (90 kg N/fad) gave the highest top, root and sugar yields/fad, as well as the percentage of purity compared with the other treatments in both seasons. Intercropping faba bean with sugar beet plants with application of 90 kg N + 30 m3 FYM/fad gave the highest number of leaves/plant, leaf area/plant, root length, root diameter and root weight/plant followed by intercropped sugar beet plants that fertilized with 80 kg N + 30 m3 FYM/fad compared with the other treatments in both seasons. On the other hand, intercropped sugar beet that received 400 g of Cerealine + 30 m3 FYM/fad had the highest percentages of T.S.S. and sucrose followed by 70 kg N + 30 m3 FYM/fad compared with the other treatments in both seasons. Solid culture of faba bean with the application of 20 kg N/fad gave the highest plant height, number of seeds/pod and seed yield/fad, meanwhile the highest number of branches/plant and pod length were achieved by intercropping faba bean with sugar beet with application of 90 kg N + 30 m3 FYM/fad followed by intercropped faba bean plants that fertilized with 80 kg N + 30 m3 FYM/fad compared with the other treatments in both seasons. However, intercropped faba bean plants that fertilized with 70 kg N + 30 m3 FYM/fad gave the highest number of pods per plant, number of seeds per pod, seed index and seed yield per plant compared with the other treatments in both seasons. Land equivalent ratio (LER), land equivalent coefficient (LEC) and relative crowding coefficient (RCC) were high by intercropping faba bean with sugar beet with the application of 80 kg N + 30 m3 FYM/fad indicating yield advantage was achieved. The value of aggressivity (Agg) of sugar beet was negative for all combinations indicating that sugar beet is dominated component in the present study. Intercropping faba bean with sugar beet with the application of 80 kg N + 30 m3 FYM/fad achieved higher total income and monetary advantage index (MAI) than the other treatments. Growing sugar beet plants in both sides of beds (1.2 m width) with one faba bean row in middle of sugar beet beds with the application of 80 kg N + 30 m3 FYM/fad decreased mineral N fertilizer rate by 10.00% of the recommended sugar beet mineral N fertilizer rate, as well as increased land usage and profitability for Egyptian farmers compared with sugar beet solid culture.

Management Modes of Employment Relationship under a Changing and Reforming Circumstance in China： a Competitive Advantage Perspective

Since the 1990s, organizational environments in China have taken an unprecedented, unrelenting and largely unpredictable change, competitive advantage has increasingly depended on core employees, conventional and rigid employment modes have been confronted with a serious challenge. In contrast to pervious work in employment relationship, this paper explores how to achieve and maintain sustainable competitive advantage through differential management of employees in a business climate characterized by increasingly fierce competition and diverse human resources. On the assumption that human capital is idiosyncratic and according to a two dimensional matrix of strategic value and firm-specificity of human capital, the paper establishes a binary matrix model and develops a classification of four types of workers： firm-specific core employees, generic key employees, generic ancillary employees, and idiosyncratic allied employees. Each is viewed as playing a different strategic role in organization and should be developed and supported by different employment modes： commitment management based on skill, productivity management based on job, compliance management based on short-term contact, and collaboration management based on alliance, in order to facilitate employment relationship management in congruence with other HR practices and enterprise strategy for winning sustainable competitive advantage.

Soft Information,Core Competitive Edge and Private Relationship Lending——A Case of Village Banks

In view of the development problems of village banks,through introducing the concept of private relationship lending,the functions of soft information,the channels of village banks for collecting soft information,and the private relationship lending of village banks under Chinese rural human environment of highlighting relationship while despising rationality are proved.According to the recognition standard of core competitive edge,it can be concluded that the core competitive edge of village banks is private relationship lending.In the first place,these kinds of small and medium-sized quarter banks have competitive advantages in launching private relationship lending;in the second place,the lending businesses of village banks based on soft information attracts small and medium clients;in the third place,the private relationship lending has realized the scale economy.Furthermore,the reasons why village banks can not display the core competitive edge have been analyzed:firstly,village banks have not found that private relationship lending is their core competitive edge;secondly,the internal motivation on establishing private relationship lending of village banks is insufficient;thirdly,village banks have not prepared well in developing private relationship lending;The relevant policies and countermeasures are put forward,including transforming idea and vigorously developing private relationship lending;intensifying training and improving the quality of personnel involved;strengthening supervision and avoiding the violation behaviors of personnel involved;emulating experiences and perfecting the private relationship lending mechanism of village banks.

新时代我国竞技体育发展中政社关系改革的几点思考

为更好适应新时代社会主要矛盾变化,建构我国竞技体育发展新格局,采用文献资料法和访谈法对我国竞技体育发展中政社关系改革问题进行分析。认为,我国竞技体育发展中强政府、弱社会的发展惯性仍需进一步打破,社会自组织的发展能力有待提高,政府管理的角色和职能亟需转变。新时代我国竞技体育发展需重视政社关系改革,从强政府、弱社会转变为强政府、大社会发展格局,政府引导社会力量有序发展,并与社会力量合作构建多元治理机制。具体包括:深化“放管服”改革,竞技体育“举国体制”继续做减法;社会力量加强自身建设,在更多领域发挥更大作用;依据经济发展的阶段性特征,有针对性地扶持社会力量成长;根据参与类别,对社会力量发展提供差异化的帮扶;做好市场监管,引导、规范社会力量成长;积极推进政府元治理、行业自治和多元共治。

竞争还是合作:纵向财政关系改革下的政府行为抉择

纵向财政关系的规范与协调是建立现代财政制度的必要条件。本文从省直管县财政体制改革入手,探究了纵向财政关系改革下纵向层级政府在财政竞争与合作行为之间如何抉择的问题。本文基于1997—2009年全国县级面板数据,利用计量模型开展实证分析后发现,当地级市的财政利益因省直管县财政体制改革受损时,总体来看其下辖的非改革县的财政支出和转移支付将会增加,这表明地级市为弥补自身利益会对余下非改革县进行帮扶以求合作共赢。此外,异质性分析结果表明:“强市弱县”情况下的地级市和组织政府性基金收入能力强的地级市对余下非改革县的帮扶力度较大;地级市主要借助于专项转移支付工具对余下非改革县进行帮扶而非一般性转移支付。

中国加入CPTPP的农产品贸易效应研究--基于WITS-SMART模型

粮食安全是国家安全的基石,面对国际市场不稳定性,加入CPTPP有望为中国夯实农产品贸易韧性提供新契机。在考察中国与CPTPP国家农产品贸易竞合关系的基础上,运用WITS-SMART模型建立局部均衡分析框架,研究中国加入CPTPP的农产品贸易效应,结果发现:第一,中国农产品竞争力整体不强,但与CPTPP国家依存关系较高,双边贸易潜力在关税完全削减时充分释放。第二,零关税情境下,贸易创造效应普遍大于转移效应,中国对CPTPP多数国家农产品贸易规模大幅扩张,进口增长主要源自种植业、畜牧业部门以及加拿大、澳大利亚、英国、日本等国家,出口增长主要集中于种植业部门以及日本、英国、马来西亚、墨西哥等国家。第三,加入CPTPP显著改善了双边经济福利,不过关税损失较为严重。因此,中国应破除部门利益障碍,加强与墨西哥、日本、英国等国经贸联系以充分挖掘CPTPP国家市场潜力,释放贸易自由化福利,持续提高农产品出口质量和国际竞争力以应对加入CPTPP带来的挑战。

数据抓取行为的正当性判断——反思实质性替代规则

实质性替代规则经过十余年的发展,已经成为判断数据抓取行为是否正当的基本规则之一。但是,这一从司法审判经验中发展出来的规则具有误导性,特别是该规则经过抽象而进入到各种规范性文件中时,这一问题尤其显著。实质性替代规则本质上是对同业竞争、直接竞争关系的强调,这不仅和反不正当竞争法弱化竞争关系的趋势相悖,也没有对行为的正当性有充分说明。实际上,数据抓取行为的本质是对他人成果的利用,在肯定可以适当抓取的前提下,正当性的基础应当以是否超越合理限度为标准;这需要在个案中进行判断,充分考虑抓取数据的数量、数据类型以及抓取行为造成的运维成本等因素。

供应链关系对重污染行业制造业企业环境绩效的影响

文章以2015—2021年重污染行业制造业上市公司为研究对象,并从动态的供应链关系视角出发,基于资源依赖、交易成本、信息不对称和竞争优势理论,探索性地研究供应链波动性影响制造业企业环境绩效的内在作用机制。研究结果表明:供应链波动性对制造业企业环境绩效呈负相关关系;关系型专用资产在供应链波动性与企业环境绩效之间发挥中介作用;行业竞争度在供应链波动性削弱企业环境绩效的直接路径中具有负向调节效应,即激烈的行业竞争缓解了供应链波动性对企业环境绩效的负向影响。异质性检验发现,国有制造业企业、大规模以及处于行业竞争弱组的制造业企业更容易受到供应链波动性的负面影响。

新时代我国竞技体育发展中社会和市场力量的作用及改革策略

运用文献资料法和逻辑分析法,分析新时代我国竞技体育发展中的社会和市场力量主体类别、各自发挥的作用及改革策略。指出,竞技体育发展中社会和市场主体主要为家庭、学校、民办非企业体育单位、体育企业、枢纽型体育社会组织,呈现出明显的领域分离和作用互补的特征。在竞技体育发展过程中,家庭发挥着启蒙、引导和支持作用,学校发挥着宣传、培养和拓展作用,民办非企业体育单位发挥着初步专项化发展和分类引流作用,体育企业发挥着高度专业化和定向发展作用,枢纽型体育社会组织发挥着桥梁和纽带作用。为此,应充分发挥枢纽型体育社会组织的引领作用,打造多元主体协同推进的自组织动力链条,构建多元主体优势互补的区域发展微循环。

“独乐乐”还是“众乐乐”:政策性农业保险市场适度竞争的量化研究

基于2008—2019年省级面板数据,揭示农业保险市场适度竞争的量化特征。研究发现,在省级层面,农业保险市场竞争程度与农业保险发展水平呈显著的“倒U型”关系,拐点值出现在HHI指数等于0.5左右,表明省级最优的农业保险市场竞争程度偏于适度垄断;过度竞争和过度垄断分别通过增加保险机构经营管理费用、减少保险赔付影响农业保险发展;相比于欠发达地区,经济发展水平较高的省份可以接受相对更高的市场垄断程度。考虑到当前农业保险市场普遍存在寻租和“应收保费”问题,建议将县级农险招投标权上移至省级农业保险主管部门,并形成保费补贴资金直接拨付省级保险分公司的支付机制。

竞合关系网络视角下城市大型商业设施布局优化研究

从商业设施间的竞合关系出发,以西安市为例,利用开源数据,通过商业引力模型、动态投影、修正余弦相似度计算等方法,叠加构建商业设施竞合关系网络,并从中心性、结构性、等级性、分布性、社区(组团)性、关联性、竞争性、稳定性等方面解析该网络的特征。在此基础上,结合竞合关系网络的宏观调控、动态预测和风险识别等特点,提出可能的商业设施布局优化策略,以期引导商业设施的有序开发和更新。

毛竹扩张过程中竹与树空间关系的点格局分析

毛竹与树木相互作用关系是解释毛竹扩张的关键。在井冈山自然保护区选取典型竹阔界面样地(50×100 m)调查样地内毛竹和树木的植株空间分布距离,采用Programita软件对树木与毛竹、毛竹母竹与新竹的空间关联性进行O-ring统计分析:结果发现:(1)0—100 m的整个界面区域,毛竹与树木在0—10 m任何尺度都是负关联。由毛竹纯林向混交林过渡,毛竹与树木的负相关距离加大,由2—3 m增加到2—9 m;(2)毛竹与不同生态型树木的空间关联性表现出较大差异,无论在任何区域,从0—10 m尺度上毛竹与落叶树都无关联,但在0—100 m整个界面区域,除<1.0 m尺度外,毛竹与常绿树是负关联;扩张前期(前沿区)毛竹与乔木的负相关距离比与灌木树的大;(3)毛竹母竹与新竹在不同时期不同区域的空间关联性有较大差异,在0—40 m区域内,仅2013年在1 m尺度下母竹与新竹呈正关联,在40—80 m区域内,随扩张年份增加,母竹与新竹关联尺度距离由2007年的6—7 m下降到2013年1 m和3—6 m。结果表明毛竹与树木间存在明显的相互排斥作用,竹与树的作用强弱与树木的生态型特征、扩张阶段和二者相对密度有关。毛竹扩张方式可表现为前期远距离放置新竹,扩张后期进行密度填充。研究结果可为竹子扩张程度判定及扩张预测、防控提供参考。

中国式现代化背景下竞技体育发展:逻辑关系、现实困境与实践路径

党的二十大报告提出,要以中国式现代化全面推进中华民族伟大复兴,在体育领域加快推进体育强国建设。本研究采用文献分析、专家访谈和逻辑分析等研究方法,阐明了中国式现代化与竞技体育发展之间的密切关系,剖析了当前环境下竞技体育发展面临的困难和挑战。在此基础上,重点讨论了在竞技体育发展中应如何处理好顶层设计与实践探索、战略与策略、守正与创新、效率与公平、活力与秩序、自立自强与对外开放这六对重大关系。中国式现代化为竞技体育发展提供了方向和动力,同时竞技体育的发展也推进了中国式现代化的进程,要在中国式现代化背景下促进竞技体育发展,助力实现体育强国这一宏伟目标。

金属蜂窝/石蜡复合相变材料融化储热性能研究

针对金属蜂窝/石蜡复合相变材料融化储热过程中,金属蜂窝热传导与液相自然对流传热的竞争关系,基于流-固-热三场耦合理论,建立相变材料融化储热计算模型。开展相变石蜡融化试验,验证计算模型的正确性。进一步分析液相自然对流和金属蜂窝热传导传热的增强效应,以及两者间的竞争关系。结果表明:底部加热下的密闭方腔内相变石蜡融化储热过程可分为热传导、稳定增长、过渡和紊流等四个阶段;各阶段占总融化储热时间的比例分别为0.8%、2.3%、13.6%和83.3%。热量随着液相石蜡的自然流动实现无障碍传输,达到提升相变石蜡融化储热效率的目的。自然对流传热的增强效应随尺寸减小而显著降低,在尺寸小于2 mm后可忽略不计。金属蜂窝通过增大热传导性和传热面积,达到提升相变石蜡融化储热效率的目的。嵌入金属蜂窝后,相变材料储热过程中存在多层共融现象,且在融化区形成温度梯度。与纯石蜡储热效率相比,金属蜂窝作用呈现先增强后抑制的规律,当融化分数超出临界值0.77后,金属蜂窝将进入抑制阶段。

企业数字化转型与劳动生产率的U型关系——基于市场竞争力的调节作用

基于2010—2020年中国A股上市公司研究数据,应用文本分析法刻画数字化转型指标,以双向固定效应模型为基础,实证检验企业数字化转型对劳动生产率的影响,并深入探究市场竞争力对二者关系的调节效应.研究结果表明:(1)企业数字化转型与劳动生产率呈正U型关系,即企业劳动生产率随着数字化转型的不断进行,呈现出先下降后上升的趋势.(2)市场竞争力正向调节了企业数字化转型与劳动生产率之间的正U型关系.(3)异质性分析发现,数字化转型对劳动生产率的影响作用在大规模企业、非国有企业、高新技术企业和制造业企业中更为显著.基于此,建议企业加快推进数字化转型,制定差异化的转型路径.

竞争法视角下企业数据爬取行为合规研究

企业在市场竞争中扮演着数据的控制者和爬取者的双重角色。然而,从竞争法的视角来看,企业不当利用数据爬取技术可能引发不正当竞争和数据垄断问题。为了实现企业的可持续发展,必须重新定义大数据环境下企业的实质竞争关系;健全企业数据爬取的正当标准,即设立“善意爬虫”的三重标准,以确保数据爬取范围合法合规;完善企业数据开放义务,即结合企业经营类型,明确数据授权的必要性,改进反爬措施,实现数据的开放共享。只有正确应用数据爬取技术,将其作为推动企业发展的工具,企业才能获得长足的发展。

战略共同所有权与企业全要素生产率

在经济高质量发展背景下,战略共同所有权能否高效赋能企业间合作与竞争,进而促进全要素生产率提升是值得探讨的重要命题。以2009—2022年A股上市公司为研究对象,利用组织场域理论构建微观层面战略共同所有权指标,并探索战略共同所有权对企业全要素生产率的影响。研究发现,战略共同所有权提升了企业全要素生产率,其原因在于投资组合企业间的良性竞合关系促使企业技术创新水平提升、资源配置优化以及管理能力增强。在一系列稳健性检验后,结果仍显著为正。进一步分析表明,在资源导向型以及低企业竞争地位分组中,战略共同所有权对企业全要素生产率的促进作用更加显著。从竞合关系和企业全要素生产率视角揭示了战略共同所有权影响企业高质量发展的基本逻辑和经验证据,对增强实体经济的内生增长动力具有一定的参考价值。

避免修昔底德陷阱的中国特色大国外交策略之我见

自中国成为世界第二大经济体以来,美国的对外政策愈发体现出加深与中国的对抗,以崛起国与守成国的冲突为主要表现形式的国际格局形成。同时,部分西方学者开始借修昔底德陷阱暗喻中美之间的大国博弈。经过分析认为,中美两国的关系并不符合修昔底德陷阱的各个要素,中美之间并未爆发直接冲突,在很多领域还存在着密切合作,形成了一种新竞争关系。基于此,中国应把握两国关系的实质,构建竞争与合作并进的中美关系,实施中国特色的大国外交政策,发挥国际组织在危机调解中的重要作用。