中国木质林产品贸易G-L指数测度及评价

中国木质林产品贸易发展过程中,产业内贸易的增长愈发重要。通过实证数据分析1993-2004年中国木质林产品产业内贸易的发展规律,明确了林产品产业内贸易程度的变化趋势等问题。结合实证考察产业内贸易G-L水平测度及优化指数设置,认为在木质林产品贸易总体规模扩大的基础上应充分发挥优势产品,提高其产业内贸易程度。

闽台农产品产业内贸易G-L指数分析

认为闽台农产品贸易是海峡两岸农业合作与交流的重要内容。选取2000-2009年闽台农产品贸易数据,借助G-L指数,对闽台农产品产业内贸易状况进行实证分析,并探讨影响闽台农产品产业内贸易发展的主要因素。根据研究结果,提出发展闽台农产品产业内贸易的对策建议。

基于G-L指数的中国工业制成品产业内贸易水平与类型研究

产业内贸易的出现与发展是二战后国际贸易结构发生的显著变化之一。中国产业内贸易起步于20世纪90年代,发展水平明显落后于发达国家。通过选取1992年至2012年的中国对外贸易数据,对中国工业制成品产业内贸易发展水平进行测度,据此确定中国产业内贸易的类型,并提出中国发展工业制成品产业内贸易的对策与建议。

带扰动Lévy风险过程的G-S函数

通过对带扰动项的Lévy风险过程的研究得到了其罚金折现期望(G-S)函数满足的更新方程,并给出了它的一个无穷级数表达式.

Effects of Nitrogen Fertilizer Management on Biological Traits and Physiological Indexes at Seedling Stage and Yield of Directly-sown Rapeseed(Brassica napus L.)

Field experiments were carried out to study the effects of different nitroge- napplication rates and application times on biological traits and physiological indexes of directly-sown rapeseed （Brassica napus L.） at the seedling stage and investigate the relationship between these biological traits or physiological indexes at the seedling stage and yield, so as to provide scientific theoretical support for high yield and efficient fertilization management in production of winter rapeseed. Field trials were conducted in Chengdu plain of Sichuan Province under rice-rapeseed rotation system during the period of 2011-2012. The nitrogen application rate trial consisted of five nitrogen levels （0, 90, 180, 270 and 360 kg/hm2） and the nitrogen application time trial included NTl（single application as base fertilized）, NT2 （bottom application ＋one time of topdressing at seedling stage） and NT3 （bottom application＋two times of topdressing at seedling stage） under the same nitrogen rate （225 kg/hm2）. The results indicated that compared with no nitrogen application （NO） treatment, the in- crease of nitrogen fertilizer is beneficial to the increase of biological traits including plant height, green leaf number, leaf area index and dry weight of rapeseed at the seedling stage, the improvement of physiological indexes including total nitrogen content, chlorophyll content and soluble protein content of functional leaves, and the reduction of soluble sugar content. Nitrogen rate was linearly correlated with various biological traits at the seedling stage and physiological indexes including total nitro- gen content, chlorophyll content and soluble sugar content in functional leaves over- a/I, but in parabolic correlation with soluble protein content. Under the same nitrogen rate, NT2 treatment exhibited biological traits remarkably or significantly higher than NT1 treatment and NT3 treatment. The nitrogen application times were linearly cor- related with the physiological indexes of functional leaves at the seedling stage. The various biological traits and physiological index of functional leaves at the seedlings stage were in quadratic function parabolic correlation with seed yield, and the corre- lation was significant （P〈0.05）. Therefore, under the rice-rapeseed rotation system in Chengdu plain, the economic rational nitrogen rate is 180-225 kg/hm2, and the mode of bottom application ＋ one time of topdressing （NT2） is suitable.

基于G-L法的黑龙江省产业内贸易发展实证分析

产业内贸易作为不同国家之间对于同种产业的产品同时进行进口和出口的贸易行为,在国际贸易中所占份额日益提高。近年黑龙江省外贸规模增长迅速,贸易结构不断优化,通过产业内贸易指数的测算,产业内贸易总体发展水平呈上升趋势,但速度基本表现迟缓,竞争力依然有限。我们应从培育规模经济、加大对主导产业的政策支持力度、实施产品差异化战略、发展直接投资等角度来采取对策,以促进黑龙江省产业内贸易的快速健康发展。

车辆产业内G-L指数与CA指数的关系研究

车辆产业的产业内贸易水平(G-L指数)对产业竞争力(CA指数)起着重要的影响:技术密集型产品G-L指数高,CA指数却较低,劳动密集型产品G-L指数低,CA指数却高;技术密集型产品之间,G-L指数与CA指数呈正相关关系,而劳动密集型产品之间两者却呈负相关关系;从时间序列来看,整个产业和每个产品的两指数呈正相关关系。所以,扩大车辆及零附件制造业的产业内贸易可以提升该产业的竞争力。

基于G-L指数的中德产业内贸易分析

文章结合产业内贸易理论,利用G-L指数模型对中德1996-2010年双边贸易进行实证分析,结果表明,SITC 5、SITC 6、SITC 7、SITC 8这四类工业制成品贸易的主要形式是产业内贸易,而且中德双边贸易呈现由劳动密集型向资本密集型转变的趋势。同时,通过计量分析得出,中国的市场规模及德国对中国的直接投资是影响中德制成品产业内贸易的主要因素,但对不同类型制成品的产业内贸易水平的影响程度不相同。

Assessment of Photochemical Reflectance Index as a Tool for Evaluation of Chlorophyll Fluorescence Parameters in Cotton and Peanut Cultivars Under Water Stress Condition

The relationships between photochemical reflectance index （PRI） and the chlorophyll fluorescence parameters were examined to assess suitability of PRI as a remote-sensing tool for the chlorophyll fluorescence parameters. A greenhouse experiment was conducted using cotton and peanut crops under water stress condition. Five cotton and six peanut cultivars were grown using Andosole soil in pots maintained at two water levels; the control and water stress treatment （WS） of 100 and 50% of the daily transpiration, respectively. Higher non-photochemical quenching （NPQ） was exhibited by peanut than that of cotton by the water stress. On the other hand, the decreases of the actual quantum yield of photosystem II （△F/F＇m） and PRI by the water stress in cotton were larger than those in peanut. There were positively significant correlation coefficients between PRI and △F/F＇m in cotton at noon and in the afternoon including the control and WS. The correlations of PRI with NPQ were negatively significant at noon and in the afternoon for cotton, and in the afternoon for peanut. No clear relationship was found among these parameters in the morning probably due to the diurnal increase in global solar radiation. It was concluded that there would be a possibility to detect the effects of water stress on △F/F＇m and NPQ by PRI with some exceptions, although PRI could not note varietals differences in △F/F＇m and NPQ for each treatment.

Relationship of 2 100-2 300 nm Spectral Characteristics of Wheat Canopy to Leaf Area Index and Leaf N as Affected by Leaf Water Content

The effects of leaf water status in a wheat canopy on the accuracy of estimating leaf area index (LAI) and N were determined in this study using extracted spectral characteristics in the 2 000-2 300 nm region of the short wave infrared (SWI) band. A newly defined spectral index, relative adsorptive index in the 2000-2300 nm region (RAI2000-2300), which can be calculated by RAI2000-2300 = (R2224 - R2054) (R2224 + R2054)-1 with R being the reflectance at 2224 or 2054 nm, was utilized. This spectral index, RAI2000-2300, was significantly correlated (P < 0.01) with green LAI and leaf N concentration and proved to be potentially valuable for monitoring plant green LAI and leaf N at the field canopy scale. Moreover, plant LAI could be monitored more easily and more successfully than plant leaf N. The study also showed that leaf water had a strong masking effect on the 2 000-2 300 nm spectral characteristics and both the coefficient between RAI2000-2300 and green LAI and that between RAI2000-2300 and leaf N content decreased as leaf water content increased.

基于Levenberg-Marquardt算法的无人机多传感器校正方法研究

四旋翼无人机上搭载的低成本MEMS传感器易受安装、测量、信号传输等误差的影响,导致姿态输出精度不足。为此,提出一种基于Levenberg-Marquardt (L-M)算法的三轴加速度计18个位置和三轴陀螺仪联合校正方法。在考虑传感器误差的基础上,采集并筛取3种传感器有效的输出数据,利用L-M算法对各传感器误差模型的待求参数进行最优估计。实验结果表明:校正补偿后,加速度计校正指标相比下降了98.96%,陀螺仪校正指标下降了74.33%,磁力计数据模值相比校正前与当地磁场强度差值大幅减小。此校正方法能够实现四旋翼机载MEMS传感器误差的有效补偿,具有良好的工程应用价值。

Development and Validation of National Cotton Cultivar Registration Index Model in Yangtze River Valley

[Objective] Based on the cotton variety high yielding potential, fiber quality traits, disease resistance, and early maturity characters, a cultivar registration index model was developed to simplify the tedious calculation process in national cotton registration procedure, and thus to enhance the practical application of cultivar regis- tration index in cotton breeding ancl cotton recommending. [Method] By means of correlation analysis, partial correlation analysis and path analysis methods, the cor- relation of cotton main properties and their effects on cultivar registration index were explored using the dataset of national cotton regional trials in Yangtze River Valley during 1996-2013. The cultivar registration index model was constructed with step- wise regression statistical technique to ascertain the quantitative relationship of main characters with cultivar registration index, and the regional cotton trial dataset in 2013 was used to validate the model. [Result] Several characters with larger deter- minants to cultivar registration index were screened out,ie. lint yield increase ratio, pro-frost yield ratio, verticillium wilt index, fiber strength, fusarium wilt index and mi- cronaire value. The cultivar registration index model defined the functional relation- ship of cultivar registration index with the selected main characters, among which lint yield increase ratio, fiber strength and micronaire value contributed most to culti- var registration index. The model validation with regional cotton trials in 2013 indi- cated the root mean square error, RMSE was only 2.77, and the variation coeffi- cient was 6.77%, which confirmed the model prediction effect was quite perfect. [Conclusion] The developed cultivar registration index model was reliable enough to simulate the complicated scoring system in cultivar registration procedure, also sim- plified cotton registration process, and enhanced the practicability of the cultivar reg- istration index.

Predictors of bowel damage in the long-term progression of Crohn’s disease

BACKGROUND Crohn’s disease(CD)is a chronic inflammatory bowel disorder that progresses to bowel damage(BD)over time.An image-based index,the Lémann index(LI),has been developed to measure cumulative BD.AIM To characterize the long-term progression of BD in CD based on changes in the LI and to determine risk factors for long-term progression.METHODS This was a single-center longitudinal cohort study.Patients who had participated in prospective studies on the accuracy of magnetic resonance imaging using endoscopy as a gold standard and who had a follow-up of at least 5 years were reevaluated after 5-12 years.RESULTS Seventy-two patients were included.LI increased in 38 patients(52.8%),remained unchanged in 9 patients(12.5%),and decreased in 25 patients(34.7%).The small bowel score and surgery subscale significantly increased(P=0.002 and P=0.001,respectively),whereas the fistulizing subscale significantly decreased(P=0.001).Baseline parameters associated with BD progression were ileal location(P=0.026),CD phenotype[stricturing,fistulizing,or both(P=0.007,P=0.006,and P=0.035,respectively)],disease duration>10 years(P=0.019),and baseline LI stricturing score(P=0.049).No correlation was observed between BD progression and baseline clinical activity,biological markers,or severity of endoscopic lesions.CONCLUSION BD,as assessed by the LI,progressed in half of the patients with CD over a period of 5-12 years.The main determinants of BD progression were ileal location,stricturing/fistulizing phenotype,and disease duration.

基于BiLSTM-Attention的F_(10.7)指数预测模型与中国自主数据集的应用

F_(10.7)指数是太阳活动的重要指标,准确预测F_(10.7)指数有助于预防和缓解太阳活动对无线电通信、导航和卫星通信等领域的影响.基于F_(10.7)射电流量的特性,在双向长短时记忆网络(Bidirectional Long Short-Term Memory Network,BiLSTM)基础上融入注意力机制(Attention),提出了一种基于BiLSTM-Attention的F_(10.7)预报模型.在加拿大DRAO数据集上其平均绝对误差(MAE)为5.38,平均绝对百分比误差(MAPE)控制在5%以内,相关系数(R)高达0.987,与其他RNN模型相比拥有优越的预测性能.针对中国廊坊L&S望远镜观测的F_(10.7)数据集,提出了一种转换平均校准(Conversion Average Calibration,CAC)方法进行数据预处理,处理后的数据与DRAO数据集具有较高的相关性.基于该数据集对比分析了RNN系列模型的预报效果,实验结果表明,BiLSTM-Attention和BiLSTM两种模型在预测F_(10.7)指数方面具有较好的优势,表现出较好的预测性能和稳定性.

基于AHP-DEMATEL法的外来入侵植物风险评估指标体系确立

通过对外来物种风险评估的影响因素进行对比和筛选,统筹指标体系的科学性、重要性、实用性和可移植性,选取决定风险产生的关键因素,构建外来植物风险评估的典型指标体系。从入侵性、适生性、扩散性、危害性4个纬度建立基于AHP-DEMATEL法的外来入侵植物风险度量数学模型,用以揭示因素之间的相互依赖关系,识别并量化因素之间的直接和间接影响,并利用构建的评估体系和生态位模型对印加孔雀草在中国的风险性进行分析。结果表明:经济危害、防除难度、国内重视程度、耐逆性是导致入侵植物风险性系数升高的重要因素,印加孔雀草在我国的综合风险评估值P为0.82,属于高度风险性有害植物,需要在适生区建立监测预警体系,阻截该植物的扩散蔓延,以保护生态环境和农业可持续发展。

Exogenous calcium enhances the physiological status and photosynthetic capacity of rose under drought stress

Drought(water shortage)can substantially limit the yield and economic value of rose plants(Rosa spp.).Here,we characterized the effect of exogenous calcium(Ca^(2+))on the antioxidant system and photosynthesis-related properties of rose under polyethylene glycol 6000(PEG6000)-induced drought stress.Chlorophyll levels,as well as leaf and root biomass,were significantly reduced by drought;drought also had a major effect on the enzymatic antioxidant system and increased concentrations of reactive oxygen species.Application of exogenous Ca^(2+)increased the net photosynthetic rate and stomatal conductance of leaves,enhanced water-use efficiency,and increased the length and width of stomata following exposure to drought.Organ-specific physiological responses were observed under different concentrations of Ca^(2+).Application of 5 mmol·L^(-1)Ca^(2+)promoted photosynthesis and antioxidant activity in the leaves,and application of 10 mmol·L^(-1)Ca^(2+)promoted antioxidant activity in the roots.Application of exogenous Ca^(2+)greatly enhanced the phenotype and photosynthetic capacity of potted rose plants following exposure to drought stress.Overall,our findings indicate that the application of exogenous Ca^(2+)enhances the drought resistance of roses by promoting physiological adaptation and that it could be used to aid the cultivation of rose plants.

PEG-6000模拟干旱胁迫对冬黑麦生理指标的影响

为探究干旱胁迫对冬黑麦生长及生理指标的影响,使用15%聚乙二醇-6000(PEG-6000)对水培俄罗斯冬黑麦BK01模拟干旱胁迫,分别在处理0(CK)、3、6、9、12、24 h测定不同胁迫时叶片各项生理指标。结果表明,随胁迫时间的延长,冬黑麦叶片脯氨酸和丙二醛含量呈上升趋势;过氧化氢酶、过氧化物酶、超氧化物歧化酶活性、可溶性蛋白和可溶性糖含量呈先上升后下降趋势;相对含水率呈下降趋势;研究结果将为冬黑麦抗旱研究进展提供新的理论依据。

Genome-wide association with transcriptomics reveals a shade-tolerance gene network in soybean

Shade tolerance is essential for soybeans in inter/relay cropping systems.A genome-wide association study(GWAS)integrated with transcriptome sequencing was performed to identify genes and construct a genetic network governing the trait in a set of recombinant inbred lines derived from two soybean parents with contrasting shade tolerance.An improved GWAS procedure,restricted two-stage multi-locus genome-wide association study based on gene/allele sequence markers(GASM-RTM-GWAS),identified 140 genes and their alleles associated with shade-tolerance index(STI),146 with relative pith cell length(RCL),and nine with both.Annotation of these genes by biological categories allowed the construction of a protein–protein interaction network by 187 genes,of which half were differentially expressed under shading and non-shading conditions as well as at different growth stages.From the identified genes,three ones jointly identified for both traits by both GWAS and transcriptome and two genes with maximum links were chosen as beginners for entrance into the network.Altogether,both STI and RCL gene systems worked for shade-tolerance with genes interacted each other,this confirmed that shadetolerance is regulated by more than single group of interacted genes,involving multiple biological functions as a gene network.