交易持续期、交易信息与投资者行为——基于PCD模型的研究

使用PCD模型，通过引入买卖价差、交易量、交易规模、委托指令流等交易信息变量探讨交易信息对投资者行为的影响。实证研究表明，买卖价差与期望交易持续期显著正相关，不支持Easley和O’Hara（1992）的观点。同时大规模的交易能够显著地延长交易持续期，而中等规模的交易能够减小交易持续期，证实了知情交易者的隐藏交易假说。指令流信息中的买卖申报数量也对交易持续期有显著的影响，上期买卖申报数量与本期交易持续期正相关。     

区级图书馆视角下的农家书屋发展策略探析

对区属农家书屋的现状及存在问题进行了剖析,提出以区级图书馆为中心的三级图书馆服务网络是农家书屋发展的最佳模式。指出区级图书馆应利用自身优势,帮助农家书屋可持续发展。     

Can conservation tillage mitigate climate change impacts in Mediterranean cereal systems? A soil organic carbon assessment using long term experiments

Simulation models, informed and validated with datasets from long term experiments (LTEs), are considered useful tools to explore the effects of different management strategies on soil organic carbon (SOC) dynamics and evaluate suitable mitigative options for climate change. But, while there are several studies which assessed a better prediction of crop yields using an ensemble of models, no studies are currently available on the evaluation of a model ensemble on SOC stocks. In this study we assessed the advantages of using an ensemble of crop models (APSIM-NWheat, DSSAT, EPIC, SALUS), calibrated and validated with datasets from LTEs, to estimate SOC dynamics. Then we used the mean of the model ensemble to assess the impacts of climate change on SOC stocks under conventional (CT) and conservation tillage practices (NT: No Till; RT: Reduced Tillage). The assessment was completed for two long-term experiment sites (Agugliano – AN and Pisa – PI2 sites) in Italy under rainfed conditions. A durum wheat (Triticum turgidum subsp. durum (Desf.) Husn.) – maize (Zea mays L.) rotation system was evaluated under two different climate scenarios over the periods 1971–2000 (CP: Present Climate) and 2021–2050 (CF: Future Climate), generated by setting up a statistical model based on canonical correlation analysis. Our study showed a decrease of SOC stocks in both sites and tillage systems over CF when compared with CP. At the AN site, CT lost −7.3% and NT −7.9% of SOC stock (0–40 cm) under CF. At the PI2 site, CT lost −4.4% and RT −5.3% of SOC stocks (0–40 cm). Even if conservation tillage systems were more impacted under future scenarios, they were still able to store more SOC than CT, so that these practices can be considered viable options to mitigate climate change. Furthermore, at the AN site, under CF, NT demonstrated an annual increase of 0.4%, the target value suggested by the 4 per thousand initiative launched at the 21st meeting of the Conference of the Parties in Paris. However, RT at the PI2 needs to be coupled with other management strategies, as the introduction of cover crops, to achieve such target.     

杜香油主要成分的分离和鉴定

用减压蒸馏、气相色谱分离、红外和紫外光谱法、催化加氢和沸点测定等手段对杜香油中三种含量较高的成分进行了分离和鉴定。结果确定它们是月桂烯、对－伞花烃、桃金娘烯醛。并参考同条件下的ＧＣ与ＧＣ－ＭＳ结果鉴定出α－蒎烯、茨烯等化合物。测定了各成分在杜香油中的含量。     

长叶榧叶部油挥发性成分的色谱/质谱分析研究

采用气相色谱/质谱(GC-MS)联用法测定了长叶榧叶部精油的挥发性成分,初步发现其主要成分是柠檬烯、反式α-蒎烯、β-蒎烯、顺式α-蒎烯、3-莰烯、6,6-二甲基-2-亚甲基-环庚烷、β-月桂烯,其含量分别为32.2%、12.5%、7.1%、6.6%、6.6%、5.5%、4.4%.     

阶层抽样理论抽样数模型的简化

本文对阶层抽样的理论抽样数模型作了简化。简化后的模型计算简单,便于在生产上应用。     

论刘辰翁对稼轩范型的总结、继承与发展

辛弃疾是南宋词人中的大家 ,其词作对后世影响深远 ,业已成为一种文学范型 ,而宋元之际的刘辰翁对这种范型归纳得最为详尽具体 ,共有四个方面 :1)以诗文为词 ;2 )用经用史 ;3)牵雅颂 ;4)入郑卫。而这四个特点也始终贯彻在辰翁自己的词作中 ,并为其所发展 ,形成了独具面目的须溪风格     

兴安落叶松天然林丰产化培育立木度表编制方法

选择内蒙古大兴安岭林区兴安落叶松天然幼、中龄林、采用生长量分析的方法，对丰产区用立木度的理论编制丰产化培育立木度表，它能够适应兴安落叶松天然幼、中龄林林木分布不均匀、林分密度变化幅度大、生长差异明显、分布地域广等特点。结果表明立木度表易于理解、便于掌握，对于生产作业具有一定的适用性。     

基于分布式业务流程模型的建模方法分析

本文主要分析了在以Web Services为基础创建业务流程模型的过程中,如何进行分布式业务流程的元模型定义与模型中的消息管理及其方法,从而方便企业的业务整合,以实现企业资源的优化配置,从而适应复杂多变的商务环境。     

灰色模型GM(1,1)在建筑物沉降预测中的应用

建筑施工中,沉降观测是监测建筑物是否安全的重要环节,将灰色系统理论应用于建筑物沉降变形的数据分析,结合沉降观测实例,进行沉降预测结果的分析和检验,在一定程度上证实了建筑物沉降变形分析中采用灰色GM(1,1)预测方法的可行性.