A Global Ex-vessel Fish Price Database: Construction and Applications

Synopsis We describe the first effort at creating a global ex-vessel fish price database, which is required for understanding the economic behavior of participants in the world’s fisheries. We demonstrate potential applications of the database by linking it to a spatially defined catch database, which makes it possible to attach landed values to species in both time and space. This is the first database available publicly where interested members of the public, researchers and managers can easily find and access ex-vessel prices of the world’s major commercial fish species. Preliminary results indicate that the average real price of a number of species have declined between 1950 and 2002. The estimated landed value of fish globally, in year 2000 dollars, was about US$24 billion in 1950. It increased steadily to about US$90 billion in the early 1970s, reached a peak of US$100 billion at the end of the 1980s, and declined to about US$80 billion in 2000. The top 15 fishing countries cumulatively account for 79% of total real landed value, with Japan leading, even though the value of its landings has been declining.      

‘How do you feel about a disease?’ The effect of psychological distance towards a disease on health communication

Based on construal level theory, this research addresses the moderating role of an individual's psychological distance towards a disease in the effectiveness of advertising messages framed by two distinctive construal level terms (high-level and low-level). In Experiment 1, two different disease types (bronchitis/distant disease vs. influenza/proximal disease) were featured, with the result that an advertisement with high-level construal terms was more persuasive for a psychologically distant disease (bronchitis) than for a psychologically proximal disease (flu). The reverse was true for an ad framed with low-level construal terms. To replicate Experiment 1 and further test the hypothesis, in Experiment 2, the perceived distance individuals have towards one disease (cancer) was measured and used as independent variable. Consistent with the results from Experiment 1, the low-level construal messages were more effective under the psychologically close condition than the psychologically distant condition. Reverse was true for the high-level construal messages.     

甘肃省县域经济差异变动的空间分析

以甘肃省县域单元为研究对象,综合运用SPSS、GeoDA和ARCGIS 9.2软件,对甘肃省县域经济发展时空差异分析后发现:甘肃省各县整体发展比较落后且经济发展差异有拉大趋势;县域经济发展水平呈现出西高东低,北高南低的趋势;1999—2008年甘肃省县域人均GDP中心,位于肃南县并向西北移动;空间聚集特征明显,经济发达地区位于河西地区;按照2008年甘肃省各县经济发展水平综合指数,甘肃省各县可分为经济发达地区、经济较发达地区、经济欠发达地区和经济不发达地区;1999—2008年人均GDP平均增长速度和相对发展率表明,河西地区发展速度明显快于其它地区。     

Incomplete Credit Markets and Commodity Marketing Behaviour

We use a simple theoretical model of seasonal market participation in the presence of liquidity constraints and transaction costs to explain the ‘sell low, buy high’ puzzle in which some households do not take advantage of inter‐temporal price arbitrage through storage and sell output postharvest at prices lower than observed prices for purchases in the subsequent lean season. We test our model with data from western Kenya using maximum likelihood estimation of a multivariate sample selection model of market participation. Access to off‐farm income and credit indeed seem to influence crop sales and purchase behaviours in a manner consistent with the hypothesised patterns.     

黑龙江省城市土地利用效益时空差异分析

城市土地利用效益是衡量城市土地利用水平的一项重要指标.文章从经济一社会一生态三个方面构建适合黑龙江省城市土地利用效益评价的指标体系,运用最优组合赋权法和协调度对黑龙江省12个地级市2002-2009年间城市土地利用综合效益水平进行分析比较;以评价结果为样本点,通过聚类分析得出全省城市土地利用综合效益水平的空间分布差异.结果表明:在时问上,12个地级市的土地利用效益水平呈现不同变化趋势;根据评价结果将12个城市分为土地利用高效益地区、中等效益地区和低效益地区三大类;在空间上,城市土地利用效益水平呈现"T"型的分布特征,"T"型区域内城市用地效益水平高于其它地区.     

基于时域分割的DS/FH信号参数估计

针对时频分析方法在直扩/跳频(DS/FH)混 合扩频信号参数估计中存在时频分辨率受限、交叉项干扰、实时性差等缺点,通过分 析DS/FH信号的时频特性,提出了一种新的DS/FH信号参数估计方法。该方法从待测信号的时 域分析出发,利用不同跳频点对应的周期数不相等的性质,完成了对DS/FH信号的时域分割 ,最后结合DS/FH信号性质完成了对待测信号跳频周期、驻留时间、跳频频率的估计。仿真 结果表明,该方法针对DS/FH信号的参数估计精度高,运算速度较快,且没有干扰频率。     

区域高质量发展的时空演变及驱动因素分析 ——以甘青宁地区为例

从经济发展、社会和谐、生态安全、城乡融合出发构建指标体系,运用熵值法、变异系数法和地理探测器对甘青宁地区高质量发展的时空演变特征和驱动因素进行研究。结果表明,2010-2018年甘青宁地区高质量发展总体向好,但地区差异逐渐拉大,高质量发展仍处于初级阶段;经济发展、社会和谐、生态安全、城乡融合水平总体均呈增长趋势,经济发展和生态安全水平地区差异逐渐缩小,社会和谐和城乡融合水平地区差异逐渐扩大;高质量发展的主要驱动因素是经济发展,第三产业增加值占GDP比重、每千人口卫生技术人员数、森林覆盖率、城乡人均消费支出比分别是经济发展、社会和谐、生态安全和城乡融合的主要驱动因素,各层级任意两因子交互后解释力更强。基于以上结论得出了政策启示。     

不同类型建设用地扩张的时序及空间特征——加速失效模型在静海区的应用

研究目的：分析城市扩展中交通用地、商住用地和工业用地扩张的时序特征、空间关系以及扩张时点的影响因素。研究方法：农地—建设用地转换最优时机理论;加速失效模型。研究结果：（1）不同类型建设用地在扩张过程中具有相互关联的时序和空间特征;（2）静海区交通用地引导了其他建设用地扩张的方向,而不同级别交通用地由于对建设用地和农用地影响的差异,加快或延缓了建设用地扩张的时机;（3）商住和工业用地在200— 400 m 范围内相互集聚,且商住用地产生的集聚效应强于工业用地。研究结论：细化建设用地类型以分析城市扩张的特征和机制,有助于城市扩展区的布局优化和集约发展。     

改革开放以来中国工业化与城市化协调发展分析

在阐述工业化与城市化协调发展涵义的基础上，引用了协调度概念，建立了工业化综合水平指数与城市化综合水平指数之间协调度模型，并对1978年以来的中国区域工业化与城市化协调发展的时空分布进行了分析。研究结果显示：①从时间上看，我国工业化与城市化基本经历了两个明显的阶段，即1978-1991年是我国工业化与城市化不协调发展时期，而1992-2001年是基本协调发展时期；②从空间上看，我国区域工业化与城市化协调发展明显存在着地带性差异：东部地区的大部分省区协调发展程度较高，中西部除了少数省区协调发展程度较高外，其它大部分省区的协调发展都较低；③我国省区的工业化与城市化协调发展的地区分布和区域经济发展水平存在很大的空间对应关系，即经济发展水平高的省区的协调发展程度相对较高，而经济发展水平相对较低省区协调发展相对较低。