PRODUCTIVE GOVERNMENT EXPENDITURE IN A STOCHASTICALLY GROWING OPEN ECONOMY

This paper employs a stochastic endogenous growth model with productive government expenditure in a small open economy to analyze the optimal fiscal policy. First, a stochastic model of a small open economy is constructed. Second, the equilibrium solutions of the representative agent＇s stochastic optimization problem are derived. Third, we obtain the equilibrium solutions of the central planner＇s stochastic optimization problem and the optimal government expenditure policy. Finally, the optimal tax policy is characterized.     

内生偏好零售商采购决策分析

讨论零售商采购决策问题,除要考虑各种成本与收益因素之外,还考虑决策者的风险偏好,假设零售商在出现损失时,以指数衰减最快扭亏,类似决策者具有损失规避。通过建立数学模型,讨论了最优采购决策的特性。分析结果显示,内生偏好的损失规避零售商的采购行为在一定的条件下和风险中性、风险规避零售商不同。     

Ethanol and opioid receptor signalling

Summary Ethanol may modulate endogenous opioid systems by disrupting opioid receptor signalling. Low concentrations of ethanol slightly potentiate -opioid receptor binding by increasing receptor B_max, and, in some cases, chronic ethanol exposure decreases the density or affinity of the -opioid receptors. By contrast, high concentrations of ethanol acutely decrease -opioid receptor binding by decreasing receptor affinity, whereas chronic exposure of animals and neuronal cell lines to lower concentrations of ethanol leads to possibly adaptive increases in the density or affinity of the -opioid receptors. In the neuronal cell line NG108-15, ethanol does not up-regulate the -opioid receptor by blocking receptor degradation or endocytosis, but protein synthesis is required for this response. Up-regulation of the -opioid receptor renders ethanol-treated NG108-15 cells 3.5-fold more sensitive to opioid inhibition of adenylyl cyclase. Long-term treatment with ethanol also increases maximal opioid inhibition in NG108-15 cells, possibly by decreasing levels of G_s and its mRNA. Ethanol differentially modulates signal transduction proteins in three additional neuronal cell lines, N18TG2, N4TG1, and N1E-115. Ethanol-treated N18TG2 cells show the least up-regulation of the -opioid receptor, little heterologous desensitization of adenylyl cyclase, and no changes in G_s or G_i. By contrast, ethanol-treated N1E-115 cells show the largest up-regulation of the -opioid receptor, the most heterologous desensitization of adenylyl cyclase, and concentration-dependent decreases in G_s and increases in G_i. Further analysis of these related neuronal cell lines may help to identify the molecular elements that endow some, but not all, neuronal cells with the capacity to adapt to ethanol.     

知识溢出对创业的影响分析

当代创业理论,尤其是对创业机会的挖掘和利用方面的理论,已经引起了国内外学者的广泛关注。本文从理论上研究了知识溢出与创业的关系,分析了知识溢出对创业产生的影响。     

Comparison of dynamic changes in endogenous hormones and sugars between abnormal and normal Castanea mollissima

To elucidate the possible functions of endogenous hormones in the flowering of chestnut, concentrations of four endogenous hormones [indole-3-acetic acid (IAA), gibberellic acid (GA), abscisic acid (ABA), zeatin riboside (ZR)) and the soluble sugars content were measured in both normal and developmentally abnormal Chinese chestnut (Castanea mollissima) during flowering and fruiting stages. Our results showed that the contents of ZR, ABA, and GA exhibited a significant different pattern in normal trees from that in abnormal trees, while the contents of IAA and soluble sugars showed a similar change pattern between them. These results suggest that quantitative changes in endogenous hormones may correspond to different flowering and fruiting mechanisms.     

Further evidence for the dissociation of digoxin-like immunoreactivity from Na+, K+-ATPase inhibitory activity

Summary The effects of adrenalectomy or nephrectomy, carried out one hour previously, on the levels of endogenous digitalis-like factors were determined in rat plasma. Factors were assayed by digoxin-like immunoreactivity and direct Na⁺, K⁺-ATPase inhibitory activity. Digoxin-like immunoreactivity significantly decreased one hour after bilateral ablation of adrenals, while Na⁺, K⁺-ATPase inhibitory activity remained unaltered. There were no changes in either activity one hour after bilateral nephrectomy. These results suggest that digoxin-like immunoreactivity may be derived from the adrenal gland or under adrenal control and the major substances detected by digoxin-like immunoreactivity and direct Na⁺, K⁺-ATPase inhibitory activity may be different.     

牡丹切花贮藏期内源激素水平变化规律的研究

对不同温度下贮藏的牡丹切花内源激素水平的测定结果表明：低温（４℃）贮藏，内源乙烯和吲哚乙酸水平显著低于室温（１８℃）贮藏，细胞分裂素水平高于室温贮藏，低贮藏切花寿命较室温贮藏可延长１０天左右。     

新疆紫草(Arnebia euchroma)细胞培养过程中内源异戊烯腺苷(iPA)与细胞生长的相关性研究

通过ELISA法测定内源iPA,在新疆紫草细胞大量培养过程中,内源iPA的动态变化与细胞的生长具有密切的相关性.在不同的培养基中,培养过程中细胞的内源iPA含量变化是明显不同的.基本培养基(不含任何外源激素)中的激素自养型细胞其内源iPA的第二峰值在细胞生长的第10天出现;生长培养基中(基本培养基中含外源IAA和KT)的细胞其内源iPA的第二峰值在细胞生长的第5天出现,比前者约提前5天时间.与之相对应,基本培养基中细胞生长延迟期比生长培养基中细胞生长延迟期长大约5天时间,不论基本培养基还是生长培养基中,培养细胞的内源iPA变化的第二峰值与细胞快速生长密切相关.当细胞生长处于停止期时,细胞内源iPA含量均很低.     

牡丹切花衰老过程中内源激素水平变化的研究

用气相色谱(GC)和高压液相色谱(HPLC)法测定了常温(18± 2℃)和低温冷藏(4± 2℃)条件下牡丹切花衰老过程中内源激素(乙烯、IAA、ABA、CTK)含量的变化,它们对牡丹切花衰老过程的影响以及相互之间的关系进行了初步的分析和讨论。