粮食质检体系建设的现状与思考

粮食卫生质量安全是全社会共同关注的热点问题,如何开展粮食质量安全管理,保障消费安全,提升消费水平是学者们共同探讨的问题。建立和完善粮食质量安全监督检测体系,开展粮食质量安全监督检测是提高保障农产品质量安全水平的有效手段之一。本文主要阐述了目前粮食质量监督检测体系的现状和存在的主要问题,并就如何加快粮食质检体系建设方面阐述了自己的观点。     

Price premiums for organic menus at restaurants: What is an acceptable level?

This study identifies acceptable premium price levels that customers would be willing to pay for organic menu items at restaurants in the United States. Previous literature indicates that health-related and socio-demographic characteristics significantly influence consumers’ intentions to purchase organic food. To advance our understanding of how different consumers respond to changes in organic food prices, this study examines the moderating effects of the level of health consciousness (high versus low), gender (male versus female), and age (young versus old) on the relationship between premium price levels and purchasing intentions. In addition, this study further investigates acceptable premium price levels for different consumer segments at two types of restaurants (casual dining versus fine dining). The results of this study provide guidelines for menu design and strategies for restaurateurs to devise effective price premiums for organic menu options.     

Understanding heterogeneity in price changes and firm responses to a national unhealthy food tax in Mexico

To address the high prevalence of overweight and obesity in Mexico, an eight percent ad valorem excise tax on non-essential energy-dense foods came into effect on 1 January 2014. This paper estimates price changes after the tax implementation among the top four food categories and by leading vs. non-leading firms using purchase information from over 6000 urban households in the 2012–2015 Nielsen Mexico Consumer Panel. We create product-city-month specific prices that correct for potential biases associated with household and retailer characteristics. Using these corrected prices, we conduct before and after quasi-experimental analyses and find that price increases were larger than eight percent for cookies but were less than eight percent for ready-to-eat cereals, salty snacks, and pre-packaged sweet bread. For the latter food group, event-study analyses on the gradual price change over time suggest that price changes might be the result of an increasing price trend rather than the tax implementation. Firm-level analyses mostly show that price increases by the leading firms were larger than the overall increase at the food market level, helping explain variability in post-tax declines in food purchases as reported in other research. We also find that price changes are generally underestimated when we do not correct prices for biases associated with households and retailers. These results improve our understanding of the mechanisms behind heterogeneous changes in purchases after the tax implementation. Additionally, these results can assist policymakers when designing or improving taxes on non-essential energy-dense foods at a time when these policy options are high on the agenda in many places.     

Bear beta

We test whether bear market risk, time variation in the probability of future bear market states, is priced. We construct an Arrow–Debreu security that pays off in bear market states (AD Bear) from traded Standard & Poor’s (S&P) 500 index options and use its returns to measure bear market risk. We find that bear beta (exposure to bear market risk) has a strong relation with expected stock returns that is robust, persistent, and remains strong among liquid and large stocks. Historical bear beta also predicts future bear market risk exposure. We conclude that bear market risk is priced in the cross section of stock returns.     

Forecasting Bordeaux wine prices using state-space methods

Generic Bordeaux red wine (basic claret) can be regarded as being similar to an agricultural commodity. Production volumes are substantial, they are traded at high frequency and the quality of the product is relatively homogeneous. Unlike other commodities and the top-end wines (which represent only 3% of the traded volume), there is no futures market for generic Bordeaux wine. Reliable forecasts of prices can to large extent replace this information deficiency and improve the functioning of the market. We use state-space methods with monthly data to obtain a univariate forecasting model for the average price. The estimates highlight the stochastic trend and the seasonality present in the evolution of the price over the period 1999 to 2016. The model predicts the path of wine prices out of sample reasonably well, suggesting that this approach is useful for making reasonably accurate forecasts of future price movements.     

Food values and heterogeneous consumer responses to nanotechnology

Agricultural applications of nanotechnology are at a relatively early stage and little is known about consumer responses to the technology. Canadian consumer responses to food nanotechnology are examined through the lens of the Food Value Scale. Data from a survey of Canadian consumers are used to evaluate the relative importance of eleven food values to food purchase decisions. We find that taste, safety, nutrition, and price are among the most important food values to Canadians, however, consumers exhibit considerable heterogeneity with respect to the priority placed on these values. A discrete choice experiment (DCE) explores the effect of food values on choice behavior. The DCE is positioned as a sliced apple product with non-browning and antioxidant-enhanced features introduced through the use of nanocoating or a conventional coating method. Random parameters logit (RPL) and latent class models (LCM) confirm the existence of significant preference heterogeneity. The LCM identifies three classes of consumers: “supporters,” “doubters,” and “opponents” who differ in their reaction to nanotechnology and in the relative importance placed on food values such as naturalness, novelty, and convenience. The analysis shows that food values provide additional insights into consumers’ food choices and their attitudes toward novel food technologies.     

Time-varying inter-urban housing price spillovers in China: Causes and consequences

The spatial spillovers of housing prices across regions are well documented by a large body of previous studies. This paper tries to investigate the dynamic (time-varying) evolution of spatial interactions and their underlying driving factors intensively. Using a recently developed Generalized Autoregressive Score (GAS) model, this paper examines the time-varying spatial spillovers of housing prices in 70 major and median cities of China from 2006 to 2019. We find that the GAS model can well capture the impact of time-varying critical events of Chinese real estate market on the whole. However, different regions display heterogeneous variation patterns over time. Further investigation shows that inter-regional labor mobility and trades are two major channels, accounting for 1.25% and 2.58% of the monthly standard deviations of spatial spillover effects from one city to another, respectively. We also characterize and distinguish between three time-varying patterns of spatial spillovers within different regions of China. Our results shed lights on the understanding of spatial spillovers across regional real estate markets across different city network structures within China.     

Land use regulation and urban land value: Evidence from China

Land use regulation has always been regarded as one of the most crucial means of macro-control of urban growth, which can affect a city’s land values directly and further determine related urban economic well-being. Since the New Type Urbanization Strategy proposed by the government in 2014, China’s mode of urban growth has been transformed from addressing “quantity” to “quality" in the urbanization process. In this case, the regulation of land use by the Chinese government plays a more important role in urban growth. With their planned land regulatory scheme, the various instruments employed by Chinese governments have quite different mechanisms influencing land prices. However, there are no rigorous studies focusing on the land use regulation system and its impact on land values to date, particular in China. This study seeks to explore how land use regulation affects urban land values through the systematic lens. We summarize the main land use regulatory instruments based on the analysis of China’s planned land use system and urban land banking system, including the construction land quota, constraints on the allowed floor area ratio (FAR) of each land transaction parcel, and land supply restrictions. A new dataset based on land transaction data from 2007 to 2016 that covers 286 prefectural cities from the country’s coastal, central, and western regions is used in the empirical analysis. The results show that the effects of the floor area ratio (FAR) on land values are significant and positive, with the residential and commercial land supply ratio being a key factor. Moreover, the results imply that the effects of constraints on FAR and commercial land supply vary between regions. These findings indicate that the Chinese land market is considerably distorted by excessive administrative interventions by local governments, in the stage of urban transition guided, the capable regulatory instruments could play an important role in adjusting urban land prices and hence impact on urban growth.     

Stabilizing and destabilizing mechanisms: A new perspective to understand business cycles

Economists believe that economic fluctuations can be smoothed by stabilization mechanisms, such as price adjustment, embedded in the economy. While price adjustment can be seen as a stabilization mechanism, are there mechanisms that can destabilize an economy? We find that as early as 1939, Harrod discussed a destabilization mechanism, the firm's investment adjustment, illustrated in his knife-edge puzzle. We build a macro-dynamic model with investment and price as the core macroeconomic variables. Our analysis shows that the interaction between the stabilization mechanism (price adjustment) and the destabilization mechanism (investment adjustment) generates fluctuations and cycles. However, due to price stickiness, the price adjustment mechanism may not be enough to stabilize the economy. In this case, a government stabilization policy is necessary for further stabilization. As this paper also addresses the microfoundations of Keynesian quantity theory, including the choice of output and investment in optimization, it can be related to traditional Keynesian economics, with a new perspective to understand business cycles.     

Trading activities,productivity and markups: Evidence for Spanish manufacturing

This work analyses the firms' internationalisation strategies of importing intermediates and exporting output, and the potential rewards of these activities in terms of total factor productivity (TFP), as a proxy for marginal costs, and markups. It further deepens into the study of the relationship between internationalisation strategies and markups by disentangling whether it operates through affecting firms' marginal costs and/or firms' prices. The panel database employed in this paper is the Spanish Survey on Business Strategies (ESEE) for the period 2006–14. Results in the paper distinguish between SMEs and large firms and indicate that there is high persistence in the performance of these activities and in firms' TFP and markups. For SMEs, we obtain rewards from importing inputs as well as exporting output in terms of TFP and markups. For large firms, we obtain rewards in TFP from the importing activity and rewards in markups from the exporting activity. Finally, we find evidence that the effects of internationalisation strategies on markups are due to both a price channel and a marginal cost channel.