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。     

八至九月龄阿尔巴斯绒山羊在不同饲养条件下瓣胃的大体解剖和组织学变化

本文用组织切片方法观察研究了不同饲养条件下,8只8~9月龄的阿尔巴斯绒山羊瓣胃的解剖和组织学变化。研究结果表明:瓣胃的容积均以放牧羊的最大,其次为干草羊,最小的为青草羊。瓣胃的大、中、小瓣叶均以放牧羊的最高,其次为青草羊,最低的是干草羊。上皮的浅层是角化的复层扁平细胞,中间层的细胞有圆形、椭圆形;基底层的细胞是矮柱状,排列整齐。瓣胃大瓣叶黏膜上皮角化层的厚度:最厚的是干草羊、其次为放牧羊、最薄的是青草羊;大瓣叶中央肌层最厚的是青草羊、其次为干草羊、最薄的是放牧羊。     

安庆猪与淮猪面纹研究

测定肥育期的１０头安庆猪和１０头淮猪的面纹模式和生产性能,探索两者之间的关系。显示,安庆猪的面纹走向是纵横兼有,而淮猪则是以纵向为主。这庆猪的面纹数与头重、皮重、后腿率、板油重、花油重等呈显著相关,淮猪的面纹数则与出栏体重、头重、后腿率、后腿重、肾重呈显著相关,面纹数可以作为指示参数用于选择有肥育性能。     

蛋白质结构的预测及其应用

蛋白质结构的预测是结构基因组学的重要研究内容,本文就蛋白质结构预测的方法和应用进行了综述,介绍了比较建模、折叠识别、从头计算等3种方法及其在结构基因组学研究、药物设计、蛋白质设计中的应用,并且对蛋白质结构预测存在的主要问题进行了讨论,指出了今后蛋白质结构预测研究重点在于优化比对算法和计分函数以及膜蛋白的结构预测.     

Study on the adaptability of common carp (Cyprinus carpio) to diets from the perspective of digestion and absorption

As an ecologically sustainable aquaculture mode, the rice‐fish approach has been paid more attention in recent years. In rice paddies, there are plant and animal diet items available to fish, but it is not clear how common carp adapt to different diets. In view of this, common carp (initial weight 492.6 ± 30 g, n = 270) were randomly divided into three groups and fed with earthworms (group A), earthworms + duckweed (group M) and duckweed (group P) respectively. After 8 weeks under these feeding regimes, the intestinal digestive enzymes activities were assayed, and intestinal tissue sections stained with HE and AB‐PAS were used to observe the morphology. The results showed that the activities of trypsin and lipase were highest in group A, followed by group M and group P. Group A had greater intestinal fold height, fold width and fold absorption area than the other groups (p < .05), especially in the foregut. Meanwhile, the total number of mucous cells was largest in group P, followed by the groups M and A. Totally, activities and distributions of digestive enzymes, fold height, fold width, fold absorption area and number and distribution of mucous cells of common carp were affected by the type of diet. Based on these results, it was found that common carp has strong adaptability to diets, and it was speculated that the majority of digestion and absorption of protein was concentrated in the foregut, while for starch and cellulose, it was spread out along the whole intestine.     

不同结构圈舍在生态养猪生产中的应用效果比较

采用单因子完全随机试验设计,以水泥地面圈舍塑料覆膜屋顶为对照组,发酵床圈舍塑料覆膜屋顶为试验1组,发酵床圈舍采光板屋顶为试验2组,测定不同圈舍结构内3个时间点(7∶00、12∶00、17∶00)的温度变化、NH3、H2S浓度变化、试验猪生长发育状况以及经济效益差异,以此研究3种结构圈舍在生态养猪中的应用效果.结果表明:试验2组温度极显著高于对照组(P<0.01),试验1组温度显著高于对照组(P<0.05);对照组NH3浓度显著高于试验1组、试验2组(P<0.05),分别提高20.1%、33.2%,对照组H2S浓度极显著高于试验1组、试验2组(P<0.01),分别提高45.2%、74.5%;试验1组、试验2组日增质量较对照组提高14.09%、19.05%,差异显著(P<0.05),试验1组与试验2组差异不显著(P>0.05),对照组组料肉比较试验1组、试验2组高19.2%、24%,差异显著(P<0.05),试验1组与试验2组差异不显著(P>0.05);试验2组的头均纯收益408.23元,较试验1组多收入54元,较对照组多收入112.84元;试验1组较对照组多收入58.84元.发酵床圈舍采光板屋顶结构优于发酵床圈舍塑料覆膜屋顶结构和水泥地面圈舍塑料覆膜结构.     

Elevated CO2 does not favor a fungal decomposition pathway

We examined the effect of prolonged elevated CO₂ on the concentration of fungal- and bacterial-derived compounds by quantifying the soil contents of the amino sugars glucosamine, galactosamine and muramic acid. Soil samples were collected from three different terrestrial ecosystems (grassland, an aspen forest and a soybean/corn agroecosystem) that were exposed to elevated CO₂ under FACE conditions for 3-10 years. Amino sugars were extracted from bulk soil and analyzed by gas chromatography. Elevated CO₂ did not affect the size or composition of the amino sugar pool in any of the systems. However, high rates of fertilizer N applications decreased the amount of fungal-derived residues in the grassland system. We suggest that these results are caused by a decrease in saprophytic fungi following high N additions. Furthermore, our findings imply that the contribution of saprophytic fungi and bacteria to SOM in the studied ecosystems is largely unaffected by elevated CO₂.     

天山北麓褶丘陵的特征与演化

对北天山山前四排褶皱丘陵的地貌特征、组成地层与构造特征进行了研究，在此基础上探讨了山前褶皱丘陵的演化历史。第一排褶皱形成于晚第三纪中新世。上新世晚期，早更新世初期，第二排褶皱开始形成。早更新世晚期，中更新世初期，第三排褶皱开始形成。晚更新世晚期，至全新世以来，第二排褶皱与第三排褶皱一直在持续隆升，同时第四排褶皱也开始形成。     

融合重参数化和注意力机制的猪脸关键点检测方法

面部对齐是猪脸识别中至关重要的步骤,而实现面部对齐的必要前提是对面部关键点的精准检测。生猪易动且面部姿态多变,导致猪脸关键点提取不准确,且目前没有准确快捷的猪脸关键点检测方法。针对上述问题,该研究提出了生猪面部关键点精准检测模型YOLO-MOB-DFC,将人脸关键点检测模型YOLOv5Face进行改进并用于猪脸关键点检测。首先,使用重参数化的MobileOne作为骨干网络降低了模型参数量;然后,融合解耦全连接注意力模块捕捉远距离空间位置像素之间的依赖性,使模型能够更多地关注猪面部区域,提升模型的检测性能;最后,采用轻量级上采样算子CARAFE充分感知邻域内聚合的上下文信息,使关键点提取更加准确。结合自建的猪脸数据集进行模型测试,结果表明,YOLO-MOB-DFC的猪脸检测平均精度达到99.0%,检测速度为153帧/s,关键点的标准化平均误差为2.344%。相比RetinaFace模型,平均精度提升了5.43%,模型参数量降低了78.59%,帧率提升了91.25%,标准化平均误差降低了2.774%;相较于YOLOv5s-Face模型,平均精度提高了2.48%,模型参数量降低了18.29%,标准化平均误差降低了0.567%。该文提出的YOLO-MOB-DFC模型参数量较少,连续帧间的标准化平均误差波动更加稳定,削弱了猪脸姿态多变对关键点检测准确性的影响,同时具有较高的检测精度和检测效率,能够满足猪脸数据准确、快速采集的需求,为高质量猪脸开集识别数据集的构建以及非侵入式生猪身份智能识别奠定基础。     

Effect of poll flexion and dynamic laryngeal collapse on tracheal pressure in Norwegian Coldblooded Trotter racehorses

Reason for performing study: Dynamic laryngeal collapse (DLC) associated with poll flexion is a newly diagnosed upper respiratory tract obstructive disorder that causes poor racing performance. Objectives: To determine if Norwegian Coldblooded Trotters (NCTs) affected with DLC associated with poll flexion differ from normal, elite NCTs based on simple airway mechanics measurements. Methods: Five normal elite NCTs and 6 NCTs diagnosed previously with DLC underwent treadmill videoendoscopy while tracheal pressures were measured continuously. Alternating head positions were used such that horses were exercised with free head carriage and induced poll flexion at heart rates >200 beats/min. Results: Peak inspiratory tracheal pressures were significantly more negative for horses with DLC compared to the elite horses. This difference was only significant during the exercise phases when the poll region was flexed, P = 0.0015. Head position significantly affected peak inspiratory pressure for both elite and affected horses, P<0.0001. Conclusions and clinical relevance: Induced poll flexion significantly affected peak inspiratory pressure (PIP) in all horses; however, PIPs were significantly more negative in those affected with DLC. Based upon the tracheal pressure measurements recorded in this study, DLC in NCTs is a severe obstructive upper respiratory tract disorder that is induced by poll flexion.