FINANCIAL CONSTRAINTS AND INNOVATION: WHY POOR COUNTRIES DON'T CATCH UP

This paper examines micro‐level channels through which financial development can affect such macroeconomic outcomes as level of income. Specifically, we investigate theoretically and empirically how financial constraints affect a firm's innovation activities. Theoretical predictions are tested using unique firm survey data, which provide direct measures for innovations and firm‐specific financial constraints, as well as information on shocks to firms' internal funds that serve as firm‐level instruments for financial constraints. We find unambiguous evidence that financial constraints restrain the ability of domestically owned firms to innovate and hence to catch up to the technological frontier.     

Can the Augmented Solow Model with Migration Explain the Italian Internal Brain Drain?

We extend the Dolado et al. (1994) model to both inflows and outflows of migrants and assume that they have a human capital endowment that contributes to increase/decrease the stock of human capital in the receiving/sending economy. We derive the conditional convergence equation in which the impact of migration flows on the growth rate is disentangled in a pure quantity effect and in a quality or composition effect of immigration and emigration rates that accounts for the relative human capital endowment of migrants with respect to resident population. Next, we test the model with Italian regional data for the 1970–2005 time period. We find that the model provides a good explanation of the Italian experience. The quantity effect is negative for the immigration rate and positive for the emigration rate, whereas the composition effect is positive for immigration and negative for emigration. Finally, we separate the centre‐north from the south and find that the composition effect of emigration is stronger for the latter. We interpret these results as a clear evidence of a brain drain from the Mezzogiorno to the centre‐northern regions.     

The Economic Efficiency of Sampling Size: The Case of Beef Trim

The economically optimal sample size in a food safety test balances the marginal costs and marginal benefits of increasing the sample size. We provide a method for selecting the sample size when testing beef trim for Escherichia coli O157:H7 that equates the averted costs of recalls and health damages from contaminated meats sold to consumers with the increased costs of testing while allowing for uncertainty about the underlying prevalence rates of contamination. Using simulations, we show that, in most cases, the optimal sample size is larger than the current sample size of 60 and, in some cases, it exceeds 120. Moreover, lots with a lower prevalence rate have a higher expected damage because contamination is more difficult to detect. Our simulations indicate that these lots have a higher optimal sampling rate.     

Evolution of recent economic-demographic modeling: A synthesis

This paper develops a flexible framework for modeling population's role in economic growth by assessing and extending a rendering suggested by several Harvard economists. Our framework includes a ``productivity' model explaining output-per-worker growth and a ``translation' model translating that growth into per-capita terms. We specify a core economic model and several ``enriched' demographic variants that include dependency, size, and density. Regressions using a cross-country panel spanning the period 1960-1995 reveal that combined impacts of demographic change have accounted for approximately 20% of per capita output growth impacts, with larger shares in Asia and Europe. An earlier draft of this paper was presented at a conference on ``Population Change, Labor Market Transition and Economic Development in Asia,' Institute of Economics, Academia Sinica, Taipei, Taiwan, 6–9 December 2002. A pre-publication version of this paper will be presented at a joint conference (by COE/JEPA) entitled ``Towards a new economic paradigm: Declining population growth, labor market transition and economic development under globalization,' held at the Awaji Yumebutai International Conference Center, Kobe, Japan, 17–19 December 2005. We have benefited from comments by Michelle Connolly, Andrew Mason, Pietro Peretto, Warren Sanderson, Alessandro Tarozzi, Jeffrey Williamson, and two anonymous referees. Responsible editor: Junsen Zhang.     

数字化高灵敏度荧光显微镜在As_2O_3诱导MGC-803细胞核凋亡产生钙振荡研究中的应用

利用数字化高灵敏度荧光显微镜对As2O3诱导MGC-803细胞核凋亡过程中的钙振荡进行研究,通过图像中荧光强度随时间变化的规律反应钙振荡的频率和强度变化。结果证实As2O3诱导MGC-803细胞核凋亡过程中,的确引发了钙振荡,说明核钙参与了凋亡过程,并且钙振荡的频率以低频为主。对两相邻细胞核的钙振荡信号观察分析发现,两核钙强度变化曲线低频部分异常相似,几乎在同一时刻达到最高点和最低点。尽管钙波动的幅度不同,但基本频率相同,由此可初步预测钙信号以频率变化为表达特征。两细胞核凋亡呈同步化趋势,证明在受到As2O3刺激后,细胞核的凋亡不是个别现象。     

On Reinventing OBM

Abstract

This article comments on an argument in favor of a change in OBM's content and focus to include certain empirical findings and theoretical constructs derived from fields like Cognitive and Social Psychology. Specifically, the argument suggests that personal beliefs such as optimism, self-efficacy, and response-efficacy are influential determinants of behavior that give rise to achievement motivation and a success-seeking typology. By incorporating such constructs into OBM, it is suggested that the field will better align itself with related disciplines sharing the goal of promoting personal success, thereby enhancing its performance-improvement toolkit and fostering greater recognition and acceptance for itself within mainstream Psychology. After summarizing key aspects of this argument, this paper identifies certain of its associated challenges and then presents some specific strategies by which the OBM community can chart a future course for the field.     

H2O2／Fe^2＋光催化氧化法去除活性染料废水色度的研究

应用H2O2／Fe^2 光助催化氧化方法，对模拟活性染料废水和实际活性染料废水脱色作用进行研究，探讨了控制条件和影响因素。结果表明，该法对活性染料废水有很好的脱色效果，紫外光对脱色有催化作用。     

Asymptotic distributions of statistics and parameter estimates for mixed Poisson processes

Mixed Poisson processes have been used as natural models for events occurring in continuous or discrete time. Our main result is the derivation of the joint asymptotic distributions of statistics, including parameter estimators, computed in different time intervals from data generated by mixed Poisson processes. These distributions can be used, for example, to test the hypothesis about the adequacy of the mixed Poisson process against data. We provide some simulation results and test the model on actual market research data.     

煤系高岭土中铁含量的测定

通过对高岭土中含量测定方法的比较,选择以领菲罗啉法作为煤系高岭土中铁含量的测定方法,该法测定结果准确,尤其对含铁量较低的高岭土更为适合。在试验的基础上确定了测定方法的主要条件为：显色剂５ｍｌ２％领菲罗啉溶液,还原剂４ｍｌ１０％盐酸羟胺液。     

出口贸易对我国技术创新的影响效应研究

通过构建研发活动的投入产出函数,运用我国1986-2004年期间的省际Panel数据,实证检验了出口贸易对我国技术创新的影响效应。利用两个不同的估计模型,得出了相似的结论,结果表明,出口贸易通过技术溢出对地区的技术创新产生了积极的影响效应,推动了地区创新能力的提升。对东、中、西部地区的进一步分析表明,由于我国出口贸易在各地区发展不平衡,出口贸易对技术创新的影响效应存在地区性差异,呈现出东部最强、中部次之、西部较弱的格局。