菱角壳的化学成分和药理活性研究进展

近年来对菱角壳的研究主要分为化学成分和药理活性研究两个方面,其中化学成分方面的研究可以概括为生物碱、酚酸类、萜类和甾体、多糖类、黄酮类5个方面;药理活性方面的研究可以概括为抗癌活性、抗氧化活性、降低α-葡萄糖苷酶活性、保肝护肝活性、抗菌活性5个方面。目前在化学成分方面的研究较弱,从研究结果来看,没食子酸及其衍生物是菱角壳的主要药用成分。最后就菱角壳的开发利用提出了几点建议。     

Interaction between message framing and consumers’ prior subjective knowledge regarding food safety issues

This study analyzed the interaction between message frames and recipients’ prior knowledge. The hypothesis is that less prior consumer knowledge will result in a larger framing effect. That is, if the subjective knowledge of the public is low, then the controversy created by mass media regarding a specific food-related event will be larger. Empirical results show that message frame has an influence on college students’ purchasing intentions. College students showed distinct responses in purchasing intention based on different headlines and different amounts of information within articles. The results further suggest that the framing effect depends not only on message frames, but also on the prior knowledge of the message recipient. Those who have less knowledge have larger variation in their purchase intention when responding to different message frames. This suggests that people with less knowledge are more likely to panic due to mass media reports regarding a food hazard issue. More informed consumers have less dramatic responses to food safety issues compared to less informed people.     

Stock price synchronicity to oil shocks across quantiles: Evidence from Chinese oil firms

This paper investigates behaviour of stock price synchronicity to oil shocks across quantiles for Chinese oil firms. The spillover effects of the oil market on a firm are segregated into firm-specific and market-wide information. First, our results report a higher level of synchronicity by dynamic conditional correlations than by R-square since the former better captures dynamic linear dependence. Second, we find strong evidence of size effect. In particular, stock price synchronicity is generally higher in large-cap firms than in small-cap ones. Oil shocks affect synchronicity in the upper quantiles differently based on firm size. Third, we also find that synchronicity responds to oil shocks significantly in extreme low quantiles, implying that shocks in the oil market are transmitted to Chinese oil firms via firm-specific information. Finally, we determine that oil shocks have little or no immediate impact on stock price synchronicity; instead, cumulative lagged effect is evident. This evidence highlights the lagging effect of spillover of oil shocks on Chinese oil firms.     

Do regional house prices converge or diverge in China?

This paper aims to test whether the regional house prices are convergent or divergent in China using a monthly panel data set of China’s 70 large and medium-sized cities from July 2005 to December 2010. This issue is closely related to understanding the efficiency of the country-level housing policies made by China’s central government. The test results suggest that the regional house prices in China are generally divergent, and thereby the country-level policies may be inefficient since they do not explicitly take the strong heterogeneity of China’s regional housing markets into consideration. As a consequence, it may be better for China’s central government to further decentralize and devolve its governance toward the housing market to the local governments.     

保乳手术治疗早期老年乳腺癌的临床价值

目的探讨保乳手术治疗早期老年乳腺癌的临床价值。方法将我院近期收治的早期老年乳腺癌患者150例,随机分为治疗组和对照组,各75例,治疗组患者进行保乳手术,对照组患者进行传统手术,对比分析两组患者经过手术后临床疗效,以及生活质量等。结果治疗组患者的手术中出血量、拔引流管时间、总的引流量及术后并发症显著优于对照组患者(P<0.05),同时治疗组患者经手术治疗后其生活质量高于对照组患者(P<0.05)。结论相比于传统的手术保乳手术具有手术后恢复时间短、并发症少及患者生活质量高等方面的优势,在临床治疗上可以进行大力推广。     

The Keynesian Multiplier Effect Reconsidered

In the standard Keynesian framework, government spending on useless public works has a larger multiplier effect than spending on government transfer payments does. In other words, spending on useless public works increases national income by more than an equivalent increase in government transfer payments would. Nevertheless, their effects on national benefit are identical. For both, the national benefit equals the direct benefit created by the spending. If there are two income classes, some transfers reduce both the national income and the national benefit. Some government purchases completely crowd out private consumption and reduce the national benefit.     

Wealth effect and investor sentiment

This paper investigated the relationship between the U.S. stock and housing markets as well as their influence on the wealth effect of consumption and found that the stock market sentiment index can explain changes in the wealth effect. The empirical results indicate that these two markets exert a wealth effect on consumption. The estimation results of the Markov-switching model indicate two states: a state in which the stock market influences its coexistence with the housing market and a state in which the housing and stock markets are unrelated. Public optimism regarding stock market investments affects the probability of transitioning between these states.     

Spillovers between sovereign CDS and exchange rate markets: The role of market fear

As important variables in financial market, sovereign credit default swaps (CDS) and exchange rate have correlations and spillovers. And the volatility spillovers between the two markets become further complicated with the effect of market fear caused by extreme events such as global pandemic. This paper attempts to explore the complex interactions within the “sovereign CDS-exchange rate” system by adopting the forecast error variance decomposition method. The results show that there is a relatively close linkage between the two markets and the total spillover index of the system is dynamic. For most of the past, the exchange rate has a higher spillover effect on the sovereign CDS than vice versa. Moreover, after the market fear variables are introduced, the “sovereign CDS-exchange rate” system and market fear variables present bidirectional spillovers. The results of the study have particular significance for maintaining the financial stability and preventing risk contagion between markets.     

Is insurance normal or inferior? -A regret theoretical approach-

This study considers how changes in wealth affect insurance demand when individuals suffer disutility from regret. Anticipated regret stems from a comparison between the ex-post maximum and actual wealth. We consider a situation wherein individuals maximize their expected utility incorporating anticipated regret. The wealth effect on insurance demand can be classified into the risk and the regret effects. These effects are determined by the properties of the utility function and the regret function. We show that insurance can be normal when individuals place weight on anticipated regret, even though the utility function exhibit decreasing absolute risk aversion. This result indicates that regret theory is a possible explanation to the wealth effect puzzle, in which insurance is normal from empirical observation, but it should be inferior by theoretical prediction under expected utility theory.     

Impact of contracts in high yielding varieties seed production on profits and yield: The case of Nepal

Nepal’s population continues to grow, but the agricultural sector’s performance remains almost stagnant. This has led to a decline in the per capita availability of food. Increasing agricultural productivity is the key to agricultural growth, and one strategy for increasing agricultural productivity is to use improved seeds. This study investigates the impact of contract farming (CF) in high yielding varieties (HYV) of paddy seed production on costs, yield, and profits of smallholder farms in Nepal. Using farm-level data and a non-parametric propensity score matching estimator, the study finds a significant positive impact of contract HYV seed farming on revenues, profits, and yield, and a significant negative impact on total costs of production. Additionally, very small farms (⩽0.43 ha) with CF in HYV paddy seeds tend to gain the most when it comes to yield per hectare. Our estimates reveal that the average smallholder household in Nepal engaged in CF with input conditions receives higher profits. However, farmers engaged in CF with output conditions tend to have higher yields but smaller profits. Finally, farmers engaged in CF in HYV paddy seeds with both input and output conditions have the highest yield gains and significantly higher profits.