生猪养殖户从众行为存在性及形成机制研究以四川省1 127家养殖户仔猪补栏为例

[目的]多数养殖户在经营管理上往往注重短期利益,对生猪市场变化的反映是趋同的,容易在价格上涨时"一哄而上",在价格下跌时"一哄而下",这种从众行为对生猪供给造成了巨大冲击,不利于生猪生产和猪肉供给的稳定。[方法]文章以四川省12个生猪调出大县1 127个生猪养殖户为调查对象,运用二元Logistic回归法,构建了从众行为的检验模型,研究了养殖户仔猪补栏中的从众行为及其形成机制。[结果](1)养殖户仔猪补栏中存在明显的从众行为,即养殖户仔猪补栏决策明显受到其他生猪养殖者生产行为的影响;(2)从众行为服从逻辑追随律和先内后外律。当其他生猪养殖者生产效益越好时,养殖户仔猪补栏的从众行为越明显;生产规模相同的养殖户之间从众行为亦更为明显;(3)信息获取性从众和投机性从众是引起从众行为形成的内在原因;(4)生产规模及养殖技术对从众行为存在重要影响。[结论]厘清了养殖户生产中出现"一哄而上,一哄而下"群体性行为的原因,为理解生猪养殖者从众行为及生猪价格形成机制提供新的视角,丰富了农户行为及农产品价格形成机制的研究成果。     

Determinants of Credit Constraints: Evidence from Sindh,Pakistan

This article investigates the determinants of credit constraints: evidence from Sindh, Pakistan. Cross-sectional farm-level data is collected during November and December 2016. A sample of 180 farm households is selected for interviews by using a multistage, random sampling technique. This study employed a probit regression model, frequency counts, and percentages to analyze the data. Access to formal agricultural credit is relatively low in Sindh province of Pakistan, the findings of the study show that the major constraints comprise distance to the formal credit sources, lending procedure, time lag, and interest rate whereas land ownership has a negative association and reduces the constraints to access formal credit. The findings of this study also show that for efficient allocation of resources, institutional sources of credit preferred to disburse agricultural credits toward educated and young age farmers as they are more inclined to adopt new farm technology for better farm production.     

The influence of chronic and temporary accessibility on trust and policy support

Abstract

Food is very closely related to our everyday life and consumers are intolerable to food risk. The impact of media report on food risk perception has been addressed but more elaborated approach on consumers’ cognitive process of food risk perception via media is needed. Theoretically guided by accessibility theory, we examined the relationship between consumers’ perception of food risk (i.e. food schema), media use, media frame, trust, and policy support. Furthermore, anger was employed as a mediating variable influencing on trust and policy support. Results found that the level of media use had a significant positive effect on trust and policy support. Among the media frames, the government responsibility frame and corporate responsibility frame were shown to be negative predictors for trust and policy support. As for the food schema, checking schema was the most influential negative factor on trust and policy support. Anger was found to exert a negative effect on trust and policy support but this effect decreased if the level of trust was high. In terms of the relationship between media frames and the food schema on anger, most food schema reduced the strong positive effects of the media frame on anger. This means peoples’ anger induced by media frames can be diminished by individuals’ specific food schema. Both theoretical and practical implications are discussed.     

Food accessibility,diversity of agricultural production and dietary pattern in rural China

The market-oriented reform in China in the past 4 decades has greatly reshaped the consumption pattern in rural areas. In particular, farmers’ diets are more likely to depend on food market development such as food accessibility. This study investigates the role of food accessibility in the transition of dietary pattern in rural China by using the China Health and Nutrition Survey data (1997–2011) and whether food accessibility helps alleviate the deviation between farmers’ dietary pattern and the recommended dietary pattern according to China Food Pagoda 2016. The primary results indicate that food accessibility contributes to improvements in quality. In particular, food accessibility increases the consumption of oil and decreases the consumption of cereal, potatoes, and beans; fruits; vegetables; and salt. Further estimation finds evidence that along with increasing food accessibility, fruit is converging to the recommended dietary pattern in China Food Pagoda 2016, and the deviations of legumes, nuts, and oil are increasing. We also observe that the impact of food accessibility on dietary quality is stronger for those not engaged in agriculture production. Our study provides valuable implications for rural development and nutrition security in the developing world.     

基于交通可达性的京津冀城市网络集中性及空间结构研究

伴随高速公路和高速铁路基础设施建设和运营,城市间“时间距离”缩短,引起城市区位和城市关系网络发生变化.研究将GIS网络分析和社会网络分析结合起来,利用O-D矩阵和引力场模型,分析京津冀都市圈在公路、铁路、高速公路和高速铁路4种不同交通模式下,可达性的差异性及都市圈城市经济相互作用的外向和内向集中程度等.结果发现:①交通可达性对都市圈内层极化作用高于外层作用,交通按照公路→铁路→高速公路→高速铁路顺序大大提高城市间可达性.②交通可达性具有两面性.一方面提高城市经济辐射能力和城市间联系度,另一方面拉大城市间差异程度,且北京、天津以辐射功能为主,其它城市以集聚为主.③可达性在1h以内,城市对外影响力较明显,变化幅度最大的是廊坊(0.25h),在1h以上,城市经济影响力变化较弱,在2h以上影响渐渐消失.④公路、铁路、高速公路和高速铁路4种交通模式中,天津交通区位优越于北京,但在可达性和经济影响力综合作用下,北京外向集中程度(Out Degree)地位明显优越于天津,而内向集中程度(In Degree)天津高于北京.⑤可达性拓展了都市圈内层的空间范围,并引起空间结构由“多中心”结构向连续的“带状”结构演变.     

末班车可达性条件下客流诱导系统研究

首先进行系统的需求分析,说明客流诱导系统的设计必要性,在此基础上针对乘客和路网运营部门的需求设计系统的大体结构,然后为每一模块进行功能设计,使系统能够满足乘客出行查询或查看路径、时间等信息的需要,并为系统的实现提供了一定的技术方法。     

Proximity changes to what and for whom? Investigating sustainable accessibility change in the Gothenburg city region 1990–2014

This paper operationalizes the concept of sustainable accessibility by emphasizing the environmental and social dimensions of sustainability from a spatial perspective. In doing so, we develop a heuristic model that focuses on the crucial dimensions of who gets access to what by using sustainable means of movement. We apply our conceptual approach in an examination of trends in sustainable accessibility for different social groups living in Gothenburg, Sweden between 1990 and 2014. On the basis of welfare-related and time-geographical considerations, we investigate accessibility by proximity for low- and high-income earners, people with small children, and elderly people. We investigate to what extent proximity to fundamental facilities increases or decreases over time, indicating changing conditions for sustainability. The results show that opportunities for living a local life and achieving accessibility via proximity differ socially. Low-income earners and the elderly generally live closer to the facilities important for daily life than do high-income earners and parents of young children. We also show that the opportunities for various social groups to obtain access by proximity change over time. For example, we observe a trend in which over time older people face reduced opportunities to reach daily facilities in their local neighborhoods.     

Evaluating the accessibility of essential medicines in China

Objective: To evaluate the accessibility of essential medicines in China through a new system which integrated the structure, process, and effect of the National Essential Medicine Policy (NEMP).

Methods: A structural equation model was built to verify the reliability of the evaluation system. This study utilized the Delphi method to obtain the structure and process index data, and used the WHO/HAI standard method for the effect index data to evaluate the NEMP. Six regions were selected for empirical analysis so that suggestions for optimization could be put forward.

Results: The structural equation model consisted of three parts: organization structure, executive process, and effect. The factor loading of the three indicators exceeded 0.5, indicating that this model complied with the preliminary fit criteria. In the organizational structure, rules and regulations and resource investment accounted for a large proportion, indicating that they had a great impact on the effect. As for the executive process, the weight of the seven indicators were similar, and they accounted for a large proportion, indicating that each indicator had a non-negligible impact on the effect. The “p” of all the three hypothesizes was less than .01, especially the “p” of hypothesis 3 was less than .001, indicating that the structure and process of NEMP affected the accessibility of the essential medicines, and three components of the model were positively correlated.

Limitations: Some errors may exist in achieving appropriate expert selection because of potential researcher bias in the Delphi approach. The results from only six provinces in China may not be generalized nationwide.

Conclusion: The structural indicators and process indicators have a significant impact on outcome indicators, and they also have correlations. That is, the formulation and implementation of the national drug policy and related supporting measures play an important role in improving the accessibility of essential medicines.     

Coordinating debris cleanup operations in post disaster road networks

We propose a constructive heuristic that generates roadside debris cleanup plans for a limited number of equipment in the post-disaster road recovery planning problem. Travel times between cleanup tasks are not pre-fixed but depend on the blockage status of the entire road network at the time of travel. We develop a novel mathematical model that maximizes cumulative network accessibility throughout the cleanup operation and minimizes makespan. We propose several practical and robust task selection rules that favor one or both goals that are tested on realistic size road networks with deterministic and stochastic debris cleanup times.     

Market accessibility and hotel prices in the Caribbean: The moderating effect of quality-signaling factors

The purpose of the paper is to investigate the influence of market accessibility on hotel prices and how this influence is moderated by various quality-signaling factors, such as online user ratings, “thumbs up” (recommendation) percentage, hotel class, and chain affiliation. Using a randomized sample of hotels in the Caribbean islands, we employ a three-level mixed-effect linear regression model to investigate the plausible relationship between market accessibility and hotel prices. After controlling for unobserved island-level and hotel-level characteristics, the model indicates that in most periods, low market accessibility (high flight costs) leads to lower hotel prices, and this influence is mitigated by well-established positive reputations as represented by the quality-signaling factors. Our findings imply that hotels should work to increase their reputations to help buffer the impacts of inaccessibility. In an effort to increase market accessibility, one course of action is to reduce airport landing taxes and fees.