The impact of government-supported participative loans on the growth of entrepreneurial ventures

We study the employment and sales growth of entrepreneurial ventures that have received a government-sponsored participative loan (PL), a hybrid form of financing between debt and equity. We use propensity-score matching (PSM) and instrumental variable analysis (2SLS) to study a sample of 512 entrepreneurial ventures that received a PL from a Spanish government agency between 2005 and 2011. We find evidence that PLs significantly boosted their beneficiaries’ employment and sales. In the two years following loan issuance, a 1-million-Euro PL generated an increase in average employment of between 12.1 (PSM) and 14.7 (2SLS) units and an increase in sales of between 1.09 and 1.97 million Euro relative to the average for the two years prior to loan issuance. The effect is larger for high-tech, young and small entrepreneurial ventures and for those that received a PL during the global financial crisis. The effect on growth is significant and stable, and PLs increase their beneficiaries’ annual growth by 10.6% for employment and by 18.0% for sales. We do not find evidence of industry or regional spillovers, nor do we find differences in the probability of survival of PL beneficiaries after we control for their characteristics.     

我国男子篮球队篮板球拼抢能力与世界强队差距的分析

主要采用文献资料法、观察法、数理统计法和对比分析法等研究方法,对第28届奥运会中国男篮与其对手抢篮板球能力方面进行了比较、分析,发现中国男篮争抢篮板球的过程中缺乏勇猛顽强的作风,没有每球必抢的决心,身体对抗性较弱,而且过分依赖内线队员抢篮板球,全队之间在争抢篮板球时缺乏配合。不能正确处理获得篮板球后的动作,导致了快攻成功率较低,以及争夺前后场篮板球时的冲抢、挡抢意识不足,导致中国队在比赛场上对篮板球的控制力较弱。     

植物耐盐机制中的Na+/H+逆向转运蛋白

Na~ /H~ 逆向转运蛋白对植物耐盐起着重要作用,它利用质膜H~ -ATPase或液泡膜H~ -ATPase及PPiase泵H~ -ATPase产生的驱动力把Na~ 排出细胞或在液泡中区隔化以消除Na~ 的毒害。本文主要综述植物中Na~ /H~ 逆向转运蛋白研究在分子水平的最新进展。     

从科学到技术的知识传播机理研究：基于知识基因

基础研究是技术创新的重要源泉。从基础研究到技术创新的知识转化规律具有重要的理论与实践价值。鉴于以往研究中专利引文方法的局限性,本研究基于知识基因这种特殊知识单元,从知识内容流动的视角,定量研究从科学到技术的知识传播机理。以人工智能技术为研究案例,识别技术领域的知识基因和专利引用的5个关键基础学科,研究各学科与技术领域的知识关系。通过构建知识基因的传播级联网络模型,对知识基因从科学到技术的跨领域传播模式进行分析。研究发现,相比于专利科学引文,知识基因流动能够揭示从各学科到技术领域的更加真实的知识传播关系;知识基因的短期影响力水平与来源学科有关;知识基因从科学到技术的跨领域传播受到马太效应影响;受异质性知识组合效应的影响,跨领域知识基因在传播网络规模、寿命、影响力及创新“催化”能力方面优于技术领域一般知识基因,后者的产生速度和传播速度则更快。研究结论为进一步深入探究从基础研究到技术创新的知识转化规律提供了微观层面的理论基础,同时,对新兴技术领域的创新预测、基础学科布局以及科技政策的制定具有一定参考价值。     

Strategic interaction among public school districts: Evidence on spatial interdependence in school inputs

This paper provides evidence on strategic interaction among public school districts in Massachusetts. The open enrollment program in Massachusetts is unique in testing the strategic competition thesis because it allows students to attend public schools located outside their home district. For each student who transfers out, funds are deducted from the sending district's local aid distribution and added to the receiving district's local aid. Thus, school districts no longer have the assurance of a ready supply of students and funding, instead they have to compete with neighboring districts, and enact strategies that will help retain as well as attract more students. A spatial econometric framework is applied to disentangle the correlation due to strategic interaction from the one that is simply due to spatially correlated error shocks. The results show that public school districts respond positively to the expenditure decisions of neighboring districts, thereby acting strategically when setting their own spending levels.     

Expanding schooling opportunities for 4-year-olds

We use a novel quasi-experimental strategy to estimate the effect of expanding early schooling enrollment possibilities on early achievement. It exploits two features of the school system in The Netherlands. The first is rolling admissions; children are allowed to start school immediately after their 4th birthday instead of at the beginning of the school year. The second is that children having their birthday before, during and after the summer holiday are placed in the same class. These features generate sufficient exogenous variation in children’s enrollment opportunities to identify its effects on test scores. Making available one additional month of time in school increases language scores of disadvantaged pupils by 6 percent of a standard deviation and their math scores by 5 percent of a standard deviation. For non-disadvantaged pupils we find no effect.     

虎杖芪合酶基因保守区的克隆及序列分析

芪合酶是白藜芦醇合成的关键酶。本文分别以传统CTAB法、传统SDS法和改良SDS法对虎杖基因组DNA进行提取,获得符合分子生物学试验要求的高质量DNA。利用芪合酶基因保守区段的特异引物进行PCR扩增,将获得的片段进行测序分析,长度为809bp,成功克隆出虎杖芪合酶基因的保守区段,为芪合酶基因工程奠定基础。     

ACE基因I/D多态性与中国越野滑雪运动员运动能力的相关性研究

杰出的运动能力与运动相关基因的多态性密切相关。采用PCR-RFLP方法测定30名越野滑雪运动员与30名普通大学生的基因的多态性。研究结果表明,对照组等位基因频率为I=35%,D=65%,基因型频率为II=20%,I/D=30%,DD=50%,越野滑雪运动员等位基因频率为I=51.7%,D=48.3%,基因型频率为II=36.7%,I/D=30%,DD=33.3%。经卡方检验符合Hardy-Weinberg遗传平衡定律,两组间基因型频率和等位基因频率有差异,II基因型和I等位基因的频率高于对照组（P〈0.1）。ACE基因I/D多态性与中国黑龙江省越野滑运动员运动能力有相关性,提示可作为基因选材的指标。探讨中国越野滑雪运动员运动能力与ACE基因I/D多态性的关联,为越野滑雪运动员的基因选材提供前期探讨性的理论依据与基础数据。     

不同强度耐力运动训练对大鼠心肌细胞ATP敏感性钾通道表达的影响

目的:探讨不同强度耐力运动训练对大鼠心肌ATP敏感性钾通道表达的影响。方法:40只雄性SD大鼠,随机分为对照组、大强度组、中强度组和小强度组。建立大鼠运动模型,采用RT-PCR技术与Western blot技术,检测大鼠心肌KATP各亚基的表达。结果:RT-PCR结果显示,大强度组和中等强度组Kir6.1的基因表达明显高于对照组;大强度组、中等强度组及小强度组Kir6.2的基因表达显著高于对照组;大强度组、中等强度组及小强度组SUR2的基因表达均显著高于对照组;在大鼠心肌组织中未能检测到SUR1的基因表达。Western blot结果与PCR结果基本相同,但小强度组Kir6.1蛋白表达也明显高于对照组。结论:各种强度的长期耐力运动训练可增加KATP的表达。     

School quality and learning gains in rural Guatemala

I use unusually detailed data on schools, teachers and classrooms to explain student achievement growth in rural Guatemala. Several variables that have received little attention in previous studies – including the number of school days, teacher content knowledge and pedagogical methods – are robust predictors of achievement. A series of decompositions by student ethnicity and type of school shed some additional light on important questions in the Guatemalan context, and beyond. The large indigenous test score gap is not explained by differences in an extensive list of observable features of schools. The large effect for community characteristics suggests peer group effects or more general institutional differences related to services or labor markets. PRONADE community schools are associated with moderate gains vis-à-vis public schools in areas related to utilization of capacity, such as days worked. But these gains are largely offset by lower teacher capacity, which highlights the challenge of improving school quality in poor, rural areas.