蛋鸡养殖企业产业链套期保值方案

针对蛋鸡养殖企业利润波动较大的问题,本研究运用鸡蛋、玉米和豆粕期货设计产业链套期保值方案,通过OLS、B-VAR和ECM模型估计套期保值比率,对比分析套期保值的效果。结果表明:1)鸡蛋、玉米和豆粕3个品种的期货价格与现货价格分别表现为高度相关,为套期保值提供了可能性;2)预计未来期间内鸡蛋价格存在下跌风险时,蛋鸡养殖企业可以提前卖出鸡蛋期货进行套期保值,同时买入玉米和豆粕期货,降低现货利润波动的风险;3)在所选取时间阶段内OLS模型估计套期保值比率的效果比B-VAR和ECM模型更好,套期保值后的收益均值更高且标准差更低。因此,蛋鸡养殖企业可以运用期货市场进行产业链套期保值,降低企业面临的市场风险。     

出口企业的具有状态非独立效用的套期决策

探讨了由于汇率的随机波动而面临着收益风险的风险厌恶竞争性出口企业的行为，这类企业可进入无偏差的外汇无期市场，在那里对外汇风险进行无成本套期保值。通过引入状态依赖效用拓展了标准方法并考察了众所周知的分离理论和全套期理论在这种一般化框架中是否仍然成立。     

中国硬麦和大豆期货市场套期保值绩效的实证研究

为了研究中国硬麦和大豆期货市场的套期保值功能，本文利用确定套期保值比率的0LS、B-VAR、ECM和EC-GARCH四个模型和套期保值绩效的衡量指标，对上述2个期货市场的套期保值比率和绩效进行了实证研究。结果显示。硬麦期货和大豆期货4周数据的最佳套期保值比率分别是0．28和0．48，它们的套期保值绩效分别是10．27和18．85，都比其1周和2周数据的套期保值比率与绩效要高；中国大豆期货市场套期保值比率与绩效要优于硬麦期货市场。从模型上看ECM和EC-GARCH模型的套期保值比率和绩效比OLS和B-VAR模型要高，从样本区间看。样本区间外的套期保值绩效要优于样本区间内的绩效。随着全国范围内实施减免农业税政策和其他“三农”政策的落实．中国农产品期货市场的套期保值功能将得到更好发挥，在我国国民经济中将发挥更重要作用。     

我国大豆加工企业的动态套期保值业务模式

为提高我国大豆加工企业的价格风险管理水平提供理论参考,基于套期保值理论,采用ARIMA模型和VAR模型对国内大豆和豆油的价格与基差变动进行预测,提出大豆加工企业的动态套期保值业务模式。结论:大豆加工企业应首先根据未来大豆和豆油价格变化趋势的预测,确定是否存在价格波动风险并决定是否进行套期保值;其次,根据现货和期货市场的价格波动情况确定合适的套期保值比率;最后,根据预测的基差变化趋势,动态调整套期保值的交易策略。     

Developmental temperature affects phenotypic means and variability: A meta‐analysis of fish data

Fishes are sensitive to their thermal environment and face an uncertain future in a warming world. Theoretically, populations in novel environments might express greater levels of phenotypic variability to increase the chance of surviving—and eventually thriving—in the new conditions. Most research on the effect of the early thermal environment in fish species focuses on average phenotypic effects rather than phenotypic variability, but to understand how fishes will respond to rising temperatures we need to consider both the average response of the population, as well as the breadth of individual responses. Here we present the first meta‐analysis on the effects of developmental temperature in fishes. Using data from 43 species and over 6,000 individual fish, we show that a change in developmental temperature induces a significant change in phenotypic means and variability, but differently depending on whether the temperature is increased or decreased. Decreases in temperature (cool environments) showed a significant decrease in phenotypic means and no change in phenotypic variability. Increases in temperature (warm environments) showed a non‐significant increase in phenotypic means and a marginally significant increase in phenotypic variability. Larger increases in temperature saw greater increases in phenotypic variability, but no increase in the mean phenotypic response. Together, our results suggest that fishes exhibit both directed and stochastic developmental plasticity in response to warming temperatures, which could facilitate or accelerate adaptation to a changing environment.     

海南天然橡胶产业的套期保值现状及建议

天然橡胶产业对海南省经济发展有着重要的作用,天然橡胶产业的收益受人为、价格及气候因素影响。为保证其收益,对天然橡胶产业进行套期保值显得尤为重要。首先分析天然橡胶产业套期保值的原因及现状,然后针对天然橡胶产业的套期保值提出了建议:对于价格风险,应根据实际情况,合理采取套期保值;对于非灾难性气候对橡胶产量的影响,建立场外市场,通过远期或互换来进行套期保值。     

中国玉米期货市场套期保值有效性分析

为了考察中国玉米期货市场转移价格风险功能发挥的程度,利用中国大连商品交易所的玉米期货结算价格和吉林玉米中心批发市场的大连港口玉米平舱价格等数据,运用国际上比较成熟的简单回归(OLS)模型、向量自回归(VAR)模型、误差修正模型(ECM)和广义自回归条件异方差(GARCH)模型来确定玉米期货套期保值交易的最佳套期保值比率,并采用Ederington的未进行套期保值交易的方差和进行套期保值交易后方差变化的百分比方法来衡量玉米期货套期保值的有效性。结果发现:中国玉米期货市场的转移价格风险功能未能得到有效发挥。     

水文化广场应急避险功能探析——以都江堰水文化广场为例

以都江堰市水文化广场为例,分析城市广场应急避险功能完善的要点,提出广场防灾功能建设原则及建设方法,并探讨了今后广场建设中应注意的问题。     

Seed Mass,Shape and Dormancy in Arid Temperate Degraded Grassland in Northeastern Inner Mongolia,China

Extensive studies have been conducted on the relationship between seed mass, shape and persistence in soil. However, the relationship between seed mass, shape and dormancy remains unclear. Therefore, in the present study, we investigated the possible relationship of seed mass and shape with dormancy in 124 plant species from different families, differing in their growth forms, in an arid temperate degraded grassland in northeastern Inner Mongolia, China. One‐tailed t‐test was applied to assess the differences in seed mass and shape between dormant and non‐dormant species. Phylogenetically independent contrasts were used to determine whether divergence within individual clades between dormant and non‐dormant seeds was associated with seed mass or seed shape. Our results indicate that the dormant seeds were heavier than 1 mg. Species with dormant seeds had significantly larger seed mass than those with non‐dormant seeds (one‐tailed t‐test = −3·56, p = 0·0005), but there was no significant difference in seed shape between them (one‐tailed t‐test = 0·86, p = 0·195). Furthermore, the relationship between seed mass, shape and dormancy was observed to be linked to phylogeny. Copyright © 2016 John Wiley & Sons, Ltd.