基于距离相关系数和KNN回归模型的森林蓄积量估测研究

【目的】探究Landsat8 OLI数据和KNN算法在森林蓄积量估测中的潜力。【方法】以湖南省湘潭县为研究区,采用Landsat8 OLI数据和同时期的二类调查数据,通过距离相关系数筛选特征,分别采用线性回归模型(MLR)、K-近邻模型(KNN)、距离加权KNN模型(DW-KNN)和优化欧式KNN模型(FW-KNN)对森林蓄积量进行估测。使用十折交叉方法进行精度检验,对检验结果进行对比分析。【结果】3种KNN模型的估测结果均高于传统的线性模型,并且在3种KNN模型中,FW-KNN算法效果最好,决定系数达到0.69,为3种模型中最高;3种KNN模型中,本研究优化欧氏距离KNN模型的估测精度最高,其均方根误差为30.3%,相比于传统KNN模型的均方根误差降低了5.1%,相比于DW-KNN模型降低了3.3%。【结论】采用DW-KNN蓄积量估测结果明显优于其他两种模型,说明通过特征与蓄积量的相关性优化样本间的距离是一种可行的KNN优化方法。     

Cuticular protein gene LmACP8 is involved in wing morphogenesis in the migratory locust,Locusta migratoria

Cuticular proteins(CPs) are major components of the insect cuticle-associated organs such as integument and wings, although the importance of CPs for wing development and function in hemimetabolous insects remains understudied. In the present study, a wing cuticular protein LmACP8 was identified from Locusta migratoria, which belongs to the RR-2 subfamily of cuticular protein RR consensus(CPR) chitin-binding proteins. LmACP8 was mainly expressed in the wing pads and showed high expression levels before ecdysis of third-, fourth-, and fifth-instar nymphs, with its encoded protein located in the procuticle of wing pads and adult wings. Depletion of LmACP8 by RNA interference markedly reduced the amount of its protein, which consequently caused abnormal wing morphogenesis in the transition from nymph to adult of L. migratoria. We further demonstrated that the abnormal morphogenesis was caused by severe damage of the endocuticle in the wings. LmACP8 was suppressed by 20-hydroxyecdysone(20 E) in vivo, however, its expression was significantly up-regulated after knocking down the hormone receptor gene LmHR39. Thus, the LmACP8 that is negatively regulated by the LmHR39-mediated 20 E signaling pathway is involved in wing development during the nymph to adult transition.     

基于Landsat和MODIS数据融合的农牧区NPP模拟

天山北坡是中国重要的农牧业发展基地,利用遥感数据准确获取植被净初级生产力(Net primary productivity,NPP)的时空信息,对于合理分配农牧业草地资源具有重要意义。由于受到天气影响及卫星传感器受到时间分辨率和空间分辨率的限制,获取既具有中空间分辨率、又具有高时间分辨率的遥感数据比较困难。本文基于中空间分辨率Landsat 8 OLI数据与高时间分辨率MODIS数据,采用遥感数据时空融合STARFM算法,获取中空间分辨率和高时间分辨率序列的遥感数据,以天山北坡中段区域为实验区,结合CASA模型,对区域内植被NPP进行模拟。结果表明,2016年内8个时期,融合后的NDVI数据与对应时刻的Landsat 8 OLI NDVI数据的相关系数不小于0.759,偏差在0.006 2～0.009 4之间,均方根误差在0.074～0.135之间;利用融合数据与CASA模型协同模拟的NPP具有良好的空间细节信息,NPP模拟值与野外实测值决定系数R~2为0.860 1,表明两者具有较好的相关性。本研究为多源遥感影像融合技术与光能利用率模型协同模拟NPP提供了新的思路。     

猪流行性腹泻病毒SHpd/2012株Nsp8基因分析及真核表达

应用生物信息工具和分子克隆技术对PEDV SHpd/2012株Nsp8基因编码的蛋白进行了结构和功能分析以及体外表达。结果显示,NSP8蛋白是一个含有194个氨基酸的亲水性蛋白,不含信号肽和跨膜区。SHpd/2012毒株高度保守的NSP8氨基酸序列与CV777、AJ1102等毒株同源性高。NSP8蛋白也是一个单体蛋白,共有5个优势抗原表位。此外,本研究成功地在293T细胞内表达了NSP8蛋白,为进一步研究猪流行性腹泻病毒NSP8蛋白的功能提供了理论基础。     

红边与短波红外谱段玉米大豆识别能力研究

[目的]研究旨在挖掘红边、短波红外谱段对玉米大豆识别精度的提升程度,发现分辨率和谱段对作物识别的综合影响规律。[方法]采用德国Rapideye和美国Landsat-OLI数据,基于最大似然监督分类的方法,针对玉米、大豆、其他等3种地物类型。[结果]结果表明,与仅有蓝、绿、红、近红外波段相比,增加红边后总体分类精度从73.1%提高到80.5%。与仅有气溶胶、蓝、绿、红、近红波段相比,增加1个短波红外波段后,总体分类精度从72.9%提高到75.4%。[结论]中分辨率多时相数据能够弥补由于缺少短波红外、降低空间分辨率造成的识别精度的下降。     

基于GEE的山东省近30年农业大棚时空动态变化研究

针对精确获取大尺度空间范围内农业大棚的分布情况并进行长时间的序列动态监测存在数据量大、计算效率低、精度不高等问题,利用Google Earth Engine(GEE)云平台能够实现快速存取、实时处理海量卫星数据,基于多时相Landsat影像进行农业大棚时序光谱特征和纹理特征的自动提取,采用随机森林算法实现山东省农业大棚的遥感分类,从而生成了山东省近30年农业大棚的空间分布和时空动态变化图。结果表明,本文分类流程具有较高的分类精度,其平均总体精度达到91.63%,Kappa系数均值为0.8642。经分析,山东省农业大棚从1990年的6.67 km^2增加到2018年的9919.40 km^2,增长速度为354.03 km^2/a。     

绿色植物生长调节剂GGR6号和GGR8号对冬小麦生长发育及产量的影响

[目的]筛选适宜冬小麦的生长调节剂,探讨其适宜的浓度和施用方法。[方法]以邯生329为试验材料,分别采用不同浓度的新型绿色植物生长调节剂GGR6号和GGR8号对河北地区冬小麦进行试验,分析其对冬小麦生长发育及产量的影响。[结果]2种生长调节剂均能促进根茎的发育、干物质的积累、产量性状的改善及产量的增加,尤其以GGR8号20 mg/kg拌种+拔节期20 mg/kg喷施对冬小麦促进效果最好。[结论]该研究可为冬小麦生产中应用植物生长调节剂提供参考。     

Effects of two commercial diets and technical feed treatment on stomach lesions and immune system of fattening pigs

The impact of technical feed treatment and diet on stomach lesions and traits of the local and systemic immune system were investigated in fattening pigs. Feeding groups differed in technical feed treatment (standard ground meal vs. finely ground and pelleted feed) and diet (soya bean meal vs. rapeseed meal/DDGS/soya beans). Pigs were fattened approximately 10 weeks by ad libitum feeding and slaughtered subsequently. Gastric alterations were assessed by a macroscopic scoring system [macroscopic stomach score (MSC) 0 =  normal to 4 =  severe lesions]. For immunological investigations, lymphocytes from blood and jejunal tissues were isolated. T‐cell phenotyping was carried out by staining intestinal lymphocytes with monoclonal antibodies for CD4 and CD8 and flow cytometric measurements. MSC was higher in animals fed finely ground and pelleted feed compared with their counterparts. Significant interactions between diet and feed treatment considering the MSC were observed (p = 0.027). There was no effect of diet or technical feed treatment on T cells of blood, Lymphonodi gastrici or lamina propria (LP) and intraepithelial cells. However, technical feed treatment significantly affected subsets of CD4⁺, CD8⁺, CD8^low, CD4/CD8 double‐positive T cells, the mean fluorescence intensity of CD4⁺ T cells and the ratio of CD8^low/CD8^high T cells in Peyer's patches (PP). All named parameters were reduced in PP of animals fed finely ground and pelleted feed compared with animals fed standard ground meal. Furthermore, significant differences between T cells of lymph nodes and LP were observed between animals with middle MSC (MSC = 1–2.5) and animals with high MSC (MSC = 3–4). Significant alterations in T cells of PP were observed between animals of low (MSC = 0–0.5) and high MSC. The observed effects provide the evidence that the impact of technical feed treatment is not limited on the stomach lesions. Possible stimuli and consequences of the immune system should be studied in more detail.     

Long‐term habitat loss in a lightly‐disturbed population of the Indo‐Pacific humpback dolphin,Sousa chinensis

1. Coastal and estuarine waters are important ecosystems with high primary and secondary productivity, but they are prone to the impacts of habitat loss caused by anthropogenic activities. For species exclusively inhabiting coastal and estuarine waters, such as the Indo‐Pacific humpback dolphin, Sousa chinensis , irreversible habitat loss can have dramatic implications for population viability.
2. A Landsat image database was used to determine the extent of coastal changes along the northern Beibu Gulf, where a large humpback dolphin population is found. The results were compared with the standardized sighting gradient (SPUF) determined from a questionnaire survey of fishermen and likely core habitats identified by application of a global digital elevation model.
3. Both SPUF and likely core habitat results indicated a continuous distribution of the humpback dolphin along the northern Beibu Gulf. Landsat images revealed that 129.6 km² of coastal waters were permanently lost in the past 40 years, 60 km² within the likely core habitats. Although this may be considered small, the impact of such habitat loss could be substantial in some local habitats.
4. The humpback dolphin population in the northern Beibu Gulf should be regarded as one management unit, with two or more social subunits. Immediate systematic surveys are needed to fill information gaps on true distribution range and habitat‐use patterns.
5. Habitat protection actions for dolphins in the northern Beibu Gulf should include both core and linking habitats, including enacting protected areas in core habitats, mitigating anthropogenic impacts in likely habitats, restoring both coastal waters and surrounding landscape quality, effective treatment of industrial sewage discharge, and comprehensive environmental impact assessments for the planning of coastal development projects.