Improving cereal yield forecasts in Europe – The impact of weather extremes

The impact of extreme events (such as prolonged droughts, heat waves, cold shocks and frost) is poorly represented by most of the existing yield forecasting systems. Two new model-based approaches that account for the impact of extreme weather events on crop production are presented as a way to improve yield forecasts, both based on the Crop Growth Monitoring System (CGMS) of the European Commission. A first approach includes simple relations – consistent with the degree of complexity of the most generic crop simulators – to explicitly model the impact of these events on leaf development and yield formation. A second approach is a hybrid system which adds selected agro-climatic indicators (accounting for drought and cold/heat stress) to the previous one. The new proposed methods, together with the CGMS-standard approach and a system exclusively based on selected agro-climatic indicators, were evaluated in a comparative fashion for their forecasting reliability. The four systems were assessed for the main micro- and macro-thermal cereal crops grown in highly productive European countries. The workflow included the statistical post-processing of model outputs aggregated at national level with historical series (1995–2013) of official yields, followed by a cross-validation for forecasting events triggered at flowering, maturity and at an intermediate stage. With the system based on agro-climatic indicators, satisfactory performances were limited to microthermal crops grown in Mediterranean environments (i.e. crop production systems mainly driven by rainfall distribution). Compared to CGMS-standard system, the newly proposed approaches increased the forecasting reliability in 94% of the combinations crop × country × forecasting moment. In particular, the explicit simulation of the impact of extreme events explained a large part of the inter-annual variability (up to +44% for spring barley in Poland), while the addition of agro-climatic indicators to the workflow mostly added accuracy to an already satisfactory forecasting system.     

田径内涵嬗变与项目沿革新探索

对奥运会田径比赛项目、奥运历史上曾举行过的项目、田径技术、场地、规则、比赛成绩等方面的演变与发展进行新探索。     

关于地理空间数据整合与持续高效更新存在的问题分析

文章针对当前地理空间数据整合与持续高效更新所存在的问题,在地理空间数据更新中引入了“数据同化”这一思想和概念,对持续高效更新存在的问题及“地理空间数据同化”的涵义和关键技术进行了论述.     

Strong functional stability of soil microbial communities under semiarid Mediterranean conditions and subjected to long-term shifts in baseline precipitation

We investigated the effect of soil microclimate on the structure and functioning of soil microbial communities in a Mediterranean Holm-oak forest subjected to 10 years of partial rain exclusion manipulations, simulating average drought conditions expected in Mediterranean areas for the following decades. We applied a high throughput DNA pyrosequencing technique coupled to parallel measurements of microbial respiration (R_H) and temperature sensitivity of microbial respiration (Q₁₀). Some consistent changes in the structure of bacterial communities suggest a slow process of community shifts parallel to the trend towards oligotrophy in response to long-term droughts. However, the structure of bacterial communities was mainly determined by short-term environmental fluctuations associated with sampling date (winter, spring and summer) rather than long-term (10 years) shifts in baseline precipitation. Moreover, long-term drought did not exert any chronic effect on the functioning of soil microbial communities (R_H and Q₁₀), emphasizing the functional stability of these communities to this long-term but mild shifts in water availability. We hypothesize that the particular conditions of the Mediterranean climate with strong seasonal shifts in both temperature and soil water availability but also characterized by very extreme environmental conditions during summer, was acting as a strong force in community assembling, selecting phenotypes adapted to the semiarid conditions characterizing Mediterranean ecosystems. Relations of climate with the phylogenetic structure and overall diversity of the communities as well as the distribution of the individual responses of different lineages (genera) to climate confirmed our hypotheses, evidencing communities dominated by thermotolerant and drought-tolerant phenotypes.     

基于信息抽取的食品安全事件自动问答系统方法研究

针对从海量食品安全事件新闻报道中很难抽取出所需答案的问题，以食品安全事件语料库为研究对象，提出了一种基于信息抽取技术的自动问答系统。首先，利用深度学习模型TextCNN对用户输入的问题进行分类，得到其所属类型。其次，对于输入问题，借助Lucene搜索引擎找到其最佳匹配文档。再次，根据输入问题的类型，从食品安全事件数据库（采用信息抽取技术自动提取的一个结构化数据库）中筛选出该文档所包含的答案候选句集合。最后，利用深度学习模型Bi LSTM及基于答案候选句上下文的特征提取方法构建一个答案抽取模型，该模型能从给定的答案候选句集合中提取出最终答案。为检查基于食品安全事件数据库的答案候选句筛选方式及基于答案候选句上下文的特征提取方式对整个自动问答系统性能的影响，进行了多种比较实验，结果表明含有基于食品安全事件数据库的答案候选句筛选方式和基于答案候选句上下文的特征提取方式的问答系统表现最佳，其回答准确率达到44%。这相比于传统的问答系统，具有明显的优势。     

Cultivation Influences on Soil Organic Carbon Associated with Texture in Seasonally Frozen Zones

[Objective] This study aimed to examine indicative roles of texture representing soil organic carbon presence and variability subsequent to cultivation under cold temperate climates with seasonal freeze-thaw events.[Method] Three chronosequences were selected for paired comparisons.Soil samples were collected at six depths with a 10 cm increment.Analysis of variance with general linear model and regression was performed for statistical analysis.[Result] In seasonally frozen soils where fragmentation of macroaggregates was stimulated,soil organic carbon level was positively associated with clay ＋ silt proportion due to a wider textural range,better than sole clay content.Exponential function better fitted the experimental data to present progressively increased effectiveness of clay ＋ silt content in maintaining carbon.Clay content explained 12％-41％ and 14％-43％ of variation via linear and exponential functions,respectively.Accordingly,clay ＋ silt content explained 47％-65％ and 46％-70％.[Conclusion] Texture reflected soil organic carbon occurrence as consequences of reclamation.For seasonally frozen soils with wider textural ranges,it is robust to adapt clay ＋ silt content as dependent variable and exponential function.The generated algorithms provided an available pathway to estimate soil organic carbon losses following cultivation and to evaluate soil fertility.     

近55年来河西地区干旱时空演变特征及其与ENSO事件的关系

根据河西地区14个气象站点1961-2015年的逐月气象观测资料，基于SPEI指数采用Mann-Kendall趋势检验法、反距离加权插值(IDW)等方法分析了近55年来河西地区年代际、四季干旱及空间变化特征，并探讨了ENSO 事件与该区干旱的关系。结果表明：在年代际变化上，自20世纪90年代以来河西地区干旱次数增多、干旱程度加重。季节时间变化上，河西地区春、夏、秋季均呈干旱化趋势，春季干旱化趋势最为突出，夏季次之，冬季略呈变湿趋势。空间变化上，整个河西地区春季均呈干旱化趋势，而且大部分地区的春旱趋势极为显著，其中春旱趋势最显著的地方是金塔；冬季整个研究区趋于湿润化。各季节干旱高频区分别集中在：春季在金塔、民勤地区，夏季在河西西北部，秋季在河西中东部及西部的安西—玉门一线，冬季在101°E以西的河西地区。河西地区秋季SPEI与SSTA指数的相关性最为显著，春季次之，夏季最弱。ENSO事件发生强度与河西地区SPEI影响因子的多项式拟合关系表明，ENSO事件强度对温度的影响高于降水；其中在ENSO暖事件(厄尔尼诺事件)发生年份，气温有明显的上升趋势；在ENSO冷事件(拉尼娜事件)发生年份，少数年份降水有所增加，对气温的影响较弱。     

体育赛事与广州城市文化软实力发展研究

广州把承办亚运会作为发展契机，在亚运前后几年时间里承办了数百场体育赛事，推动城市跨越式 发展，并形成了独特的城市文化现象。体育赛事作为一种文化丰富了广州城市文化的内涵，从而提升了城 市的文化软实力。在后亚运时期要从打造具有特色体育赛事精品、发展景观体育塑造城市形象、发挥区域 体育赛事网络优势、发展现代体育文化产业集群、提升体育新闻媒体传播效果和重视体育赛事人才资源开 发等六个方面提升广州城市文化软实力，走新型城市化发展道路，把广州建设成为国家体育名城、国际体 育竞赛中心和国际体育大赛交流中心。     

湖北省近200年大冻年表的建立及频率特征的初步分析

本文根据历史文献灾情记载以及近代气象资料,按照一定标准,建立了湖北省过去204年(1805～2008年)大冻年表,并依据大冻年表分析了大冻的年代际变化、周期性及其与太阳黑子变化和拉马德雷现象的关系.结果表明:1)过去204年共发生大冻33次,平均每10年发生1.62次(约6.2年一遇);2)在冷期平均每10年出现2次大冻,而在暖期平均每10年出现1次大冻;3)20世纪70年代以前,大冻年存在准80、24、10、4～6年周期震荡,此后24、10年周期快速衰减,4～6年周期依然存在;4)近100年,在拉马德雷冷位相时期,大冻年平均每10年出现2.3次,重现期为4.3年;暖位相时期,大冻年平均每10年出现1.3次左右.重现期为7.5年左右;5)近200年的大冻年并不都出现在太阳黑子的峰值或谷值年,不过最近100年太阳黑子谷值年大冻出现频率增加.     

Climatic oscillations and tuna catch rates in the Indian Ocean: a wavelet approach to time series analysis

We analysed the influence of climatic oscillations [based on the Indian Oscillation Index (IOI)] on monthly catch rates of two tropical tuna species in the equatorial Indian Ocean. We carried out wavelet analysis, an efficient method of time series analysis to study non‐stationary data. Catch per unit of effort (CPUE) of bigeye tuna was computed from Japanese longline statistics from 1955 to 2002 in the equatorial Indian Ocean and CPUE of yellowfin tuna was derived from industrial purse seine statistics from 1984 to 2003 in the Western Indian Ocean. Wavelet analyses allowed us to quantify both the pattern of variability in the time series and non‐stationary associations between tuna and climatic signals. Phase analyses were carried out to investigate dependency between the two signals. We reported strong associations between tuna and climate series for the 4‐ and 5‐yr periodic modes, i.e. the periodic band of the El Niño Southern Oscillation signal propagation in the Indian Ocean. These associations were non‐stationary, evidenced from 1970 to 1990 for bigeye, and from 1984 to 1991 and then from 1993 to 2001 for yellowfin. Warm episodes (low negative IOI values) matched increases of longline catch rates of bigeye during the 1970–1990 time frame, whereas the strong 1997–1998 warm event matched a decrease of purse seine catch rates of yellowfin. We discussed these results in terms of changes in catchability for purse seine and longline.