国有资本引入与民营企业双元创新——基于2008至2019中国A股上市企业的实证研究

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Description
通过引入国有资本提升融资能力、克服制度约束是民营企业提升创新水平的重要举措,在现有研究聚焦于民营企业创新数量的基础上,本文引入了代表不同创新程度和创新类型的利用式创新和探索式创新,分析民营企业引入国有资本将如何影响其两种不同的创新行为,以及公司治理、关键人力资本激励以及市场环境等影响企业成长的关键因素在其中发挥了何种调节效果。本文收集了2008至2019年中国A股上市企业的数据,利用多期DID双重差分模型进行假设验证,得出以下结论:其一,民营企业引入国有资本将提升其利用式创新,但降低了探索式创新。其二,高管团队异质性、环境不确定性能够有效缓解国有资本对探索式创新的不利影响,提升企业探索式创新水平,并且不会降低企业的利用式创新。股权激励在提升探索式创新的同时,会降低企业利用式创新。其三,国有资本引入与市场化发展水平具有替代作用,导致市场化发展水平较高地区的企业在引入国有资本后,更倾向于利用政治关联和资源优势获利,而同时降低企业利用式创新和探索式创新。其四,国有资本引入后的控制权变化能显著提升企业的利用式创新,但对探索式创新没有显著影响。 本文揭示了民营企业引入国有资本对其双元创新的影响,以及探索了国有资本引入背景下,企业提升探索式创新的关键因素,丰富了民营企业创新能力、混合所有制改革以及正式制度与非正式制度交互等相关的内容,为相应实践提供一定启示。
Date Created
2023
Agent

Chlorella Zofingiensis as an Alternative Microalgal Producer of Astaxanthin: Biology and Industrial Potential

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Description

Astaxanthin (3,3′-dihydroxy-β,β-carotene-4,4′-dione), a high-value ketocarotenoid with a broad range of applications in food, feed, nutraceutical, and pharmaceutical industries, has been gaining great attention from science and the public in recent years. The green microalgae Haematococcus pluvialis and Chlorella zofingiensis represent

Astaxanthin (3,3′-dihydroxy-β,β-carotene-4,4′-dione), a high-value ketocarotenoid with a broad range of applications in food, feed, nutraceutical, and pharmaceutical industries, has been gaining great attention from science and the public in recent years. The green microalgae Haematococcus pluvialis and Chlorella zofingiensis represent the most promising producers of natural astaxanthin. Although H. pluvialis possesses the highest intracellular astaxanthin content and is now believed to be a good producer of astaxanthin, it has intrinsic shortcomings such as slow growth rate, low biomass yield, and a high light requirement. In contrast, C. zofingiensis grows fast phototrophically, heterotrophically and mixtrophically, is easy to be cultured and scaled up both indoors and outdoors, and can achieve ultrahigh cell densities. These robust biotechnological traits provide C. zofingiensis with high potential to be a better organism than H. pluvialis for mass astaxanthin production. This review aims to provide an overview of the biology and industrial potential of C. zofingiensis as an alternative astaxanthin producer. The path forward for further expansion of the astaxanthin production from C. zofingiensis with respect to both challenges and opportunities is also discussed.

Date Created
2014-06-10
Agent

Nannochloropsis Plastid and Mitochondrial Phylogenomes Reveal Organelle Diversification Mechanism and Intragenus Phylotyping Strategy in Microalgae

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Description

Background: Microalgae are promising feedstock for production of lipids, sugars, bioactive compounds and in particular biofuels, yet development of sensitive and reliable phylotyping strategies for microalgae has been hindered by the paucity of phylogenetically closely-related finished genomes.

Results: Using the oleaginous

Background: Microalgae are promising feedstock for production of lipids, sugars, bioactive compounds and in particular biofuels, yet development of sensitive and reliable phylotyping strategies for microalgae has been hindered by the paucity of phylogenetically closely-related finished genomes.

Results: Using the oleaginous eustigmatophyte Nannochloropsis as a model, we assessed current intragenus phylotyping strategies by producing the complete plastid (pt) and mitochondrial (mt) genomes of seven strains from six Nannochloropsis species. Genes on the pt and mt genomes have been highly conserved in content, size and order, strongly negatively selected and evolving at a rate 33% and 66% of nuclear genomes respectively. Pt genome diversification was driven by asymmetric evolution of two inverted repeats (IRa and IRb): psbV and clpC in IRb are highly conserved whereas their counterparts in IRa exhibit three lineage-associated types of structural polymorphism via duplication or disruption of whole or partial genes. In the mt genomes, however, a single evolution hotspot varies in copy-number of a 3.5 Kb-long, cox1-harboring repeat. The organelle markers (e.g., cox1, cox2, psbA, rbcL and rrn16_mt) and nuclear markers (e.g., ITS2 and 18S) that are widely used for phylogenetic analysis obtained a divergent phylogeny for the seven strains, largely due to low SNP density. A new strategy for intragenus phylotyping of microalgae was thus proposed that includes (i) twelve sequence markers that are of higher sensitivity than ITS2 for interspecies phylogenetic analysis, (ii) multi-locus sequence typing based on rps11_mt-nad4, rps3_mt and cox2-rrn16_mt for intraspecies phylogenetic reconstruction and (iii) several SSR loci for identification of strains within a given species.

Conclusion: This first comprehensive dataset of organelle genomes for a microalgal genus enabled exhaustive assessment and searches of all candidate phylogenetic markers on the organelle genomes. A new strategy for intragenus phylotyping of microalgae was proposed which might be generally applicable to other microalgal genera and should serve as a valuable tool in the expanding algal biotechnology industry.

Date Created
2013-08-05
Agent