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31.
面向养殖水体,传统光谱法对化学需氧量(Chemical Oxygen Demand,COD)检测模型构建的基础:源域(现有样本库)与目标域(检测地水体)间光谱数据独立同分布。但是当源域与目标域分布间存在差异时,由源域得到的低误差模型常在目标域上表现下滑。针对该问题,提出面向UV Vis光谱的域对抗训练网络(DAUVwpNet),将分布不同的源域和目标域数据映射至相同分布的特征空间中,使其在该空间的分布距离尽可能接近,从而在特征空间中对源域训练的目标函数也可以迁移至目标域上,以降低模型在目标域的误差。试验表明:面向同一批测试数据,DAUVwpNet的预测误差为0.78,要低于传统模型的预测误差(0.85);DAUVwpNet预测值与实测值间相关系数为0.95,要高于传统模型的相关系数(0.89)。表明了该网络能够较好对齐两域特征空间数据分布,降低因分布差异带来的COD检测误差。 相似文献
32.
基于FCN的无人机玉米遥感图像垄中心线提取 总被引:1,自引:1,他引:0
为解决农业机器人在玉米田行间行走的全局路径规划问题,该研究提出一种基于全卷积神经网络(Fully ConvolutionalNetworks,FCN)的无人机玉米遥感图像垄中心线提取方法。基于无人机获取的高精度可见光遥感图像,设计了针对农田垄中心线提取的数据集标注方法,采用滑动窗口法进行图像分块,利用深度学习语义分割网络FCN对垄中心线附近7~17像素宽度范围的垄线区域进行提取,模型在测试田块上精确率达66.1%~83.4%,召回率达51.1%~73.9%,调和平均值为57.6%~78.4%;对拼接后的图像使用影像分割投影法提取中心线,探究了垄线区域宽度对垄中心线提取精度的影响,训练采用9像素的垄区域宽度,可得到垄中心线在77 mm左右偏差范围准确率为91.2%,在31.5 mm左右偏差范围内为61.5%。结果表明,基于FCN对无人机玉米遥感图像进行处理,可得到整片田地的垄中心线栅格地图,方便农业机器人进行全局路径规划。 相似文献
33.
配电网起着输送和分配电能的作用,线路损耗给供电企业造成很大的成本投入,降低能源的利用率。分析配电网线路损耗的原因,提出降低线路损耗的具体措施,以期为配电网节能降耗、安全运行提供参考。 相似文献
34.
通过人工饲养的方式探索出白马鸡驯养的经验,即:在野生白马鸡适宜生境下建立饲养场,从育雏阶段开始进行人工投食饲养和本地土鸡带领相结合的驯养方式。目前已经完成从子一代到子二代的完整驯养、饲养流程,取得了云南省林业厅的驯养繁殖许可证。对育雏、亚成体、成体阶段的喂食量、存活情况等作了分析,认为接近原始生境的环境及本地带雏母鸡是成功的重要条件。 相似文献
35.
Zohreh Sankian Sanaz Khosravi Yi‐Oh Kim Sang‐Min Lee 《Journal of the World Aquaculture Society》2019,50(1):34-41
An 8‐week feeding trial was conducted to investigate the dietary protein requirement of juvenile mandarin fish, Siniperca scherzeri, a demersal freshwater piscivore with high commercial value in East Asia. Five isolipidic (100 g/kg) and isoenergetic (20 MJ/kg) practical diets were formulated to contain graded levels of 450, 500, 550, 600, and 650 g/kg crude protein, using mackerel fishmeal as the sole source of protein. Each of the five test diets was fed to visual satiety to triplicate groups of fish (initial mean body weight ± SE; 20.1 ± 0.2 g) reared in a recirculating freshwater system over the experimental period. Fish growth performance in terms of weight gain tended to improve with increasing dietary protein level, and the highest values were observed in those fish fed the 600–650 g/kg diets. Feed intake significantly declined as the protein content of the diet increased. Feed efficiency and protein retention tended to increase with increasing dietary protein levels, from 450 to 600 g/kg, and then declined when dietary protein content further increased to 650 g/kg. A similar trend was also found for the protein efficiency ratio, although the observed changes did not reach statistical significance. Whole‐body composition and plasma biochemical parameters were not significantly affected by the dietary protein content. Based on these findings and a broken‐line model of growth, 614.4 g/kg seems to be the proper amount of protein in a practical diet for >20 g mandarin fish. 相似文献
36.
Byron A. Hamstead Paul D. Hartfield Robert L. Jones Michael M. Gangloff 《水产资源保护:海洋与淡水生态系统》2019,29(12):2162-2175
- The Tennessee–Tombigbee Waterway is among the largest and most expensive environmental engineering projects of the 20th century. The waterway accommodates barge navigation between the Tennessee River Drainage and Mobile River Basin through a series of locks, dams, canals, and dredged and diverted streams. These structures have altered riverine habitat and fragmented lotic habitats resulting in isolated freshwater mussel populations in patches of streams such as the East Fork Tombigbee River, where 42 species were known historically.
- The first post‐waterway mussel surveys in 1987 and 1988 reported 31 taxa. During 2010 and 2011 surveys, 70 sites were sampled using both timed searches and quadrats and detected 29 extant mussel species. Between 1988 and 2010–2011 the relative abundance of nine mussel taxa decreased, whereas the abundance of 11 taxa increased. The populations of three federally listed species were detected at levels below the detection limits in 1988 as well as three non‐native unionids that appear to have colonized the East Fork Tombigbee River via the Tennessee–Tombigbee Waterway River.
- Although mussel abundance and total species richness were relatively unchanged, assemblage composition shifted toward animals typical of smaller streams rather than large rivers. This shift suggests that present‐day East Fork Tombigbee River habitats favour smaller‐bodied, thinner shelled taxa that are laterally compressed and lack shell sculpture. These taxa are likely to be better adapted to hydrologically and hydraulically variable habitats than are thick‐shelled, large bodied, and sculptured mussels.
- The results suggest that mussel assemblages are dynamic and may exhibit predictable responses to changes in hydrology, physical habitat conditions, and stream connectivity. However, examinations over broad (20+ yr) temporal scales are needed to observe these shifts. The data demonstrate the value of regular monitoring of diverse mussel assemblages and the importance of stream connectivity and flow modifications to this long‐lived group of benthic invertebrates.
37.
The genome of a Brazilian strain of Leptospira kirschneri serogroup Grippotyphosa isolated from a mare post-abortion was sequenced and analyzed. High symmetrical identity and few structural differences were found when compared with a European strain of the same serogroup, L. kirschneri serovar Valbuzzi strain 200702274. Genes associated with virulence and antimicrobial resistance were found. Knowledge of the virulence evolution of Leptospira remains limited, especially in diseases of the reproductive sphere. We highlight the importance of virulence studies in the sphere of genital leptospirosis. 相似文献
38.
LIU Jiang-Ning WANG Chu-Xin ZHANG Hong-GEN MIAO Yi-Xu GAO Hai-Lin XU Zuo-Peng LIU Qiao-Quan TANG Shu-Zhu 《作物学报》2019,45(11):1664-1671
发掘水稻黑条矮缩病的抗性基因有助于抗病品种的选育,减少黑条矮缩病对水稻生产的危害。本研究构建了包含222个家系的L5494/IR36重组自交系群体。对该群体进行黑条矮缩病的田间诱发鉴定,抗性亲本IR36发病率为28.70%,感病亲本L5494发病率为84.26%,群体发病率范围为11.21%~89.81%。利用134对分子标记构建覆盖12条染色体的遗传连锁图谱,总遗传距离为1475.97 cM,平均标记间距为11.1 cM。利用QTL IciMapping 4.0对抗黑条矮缩病QTL进行分析,共检测到4个QTL,其中第1、第2、第9染色体上QTL的表型贡献率分别为12.64%、16.00%和8.43%,抗病等位基因来自抗病亲本IR36;第6染色体上QTL的表型贡献率为10.82%,抗病等位基因来自感病亲本L5494。在此基础上,利用93-11为供体、日本晴为背景的近等基因系材料,在qRBSDV-1定位区间内检测到来自93-11的抗性QTL。本研究结果为水稻黑条矮缩病抗性基因定位及分子标记辅助选择育种提供借鉴。 相似文献
39.
通过分子标记辅助选择将耐储藏主效QTL qSS-9~(Kas)转入宁粳4号提高其种子贮藏能力 总被引:1,自引:0,他引:1
利用置换系SL36作为qSS-9位点上Kasalath等位基因的供体亲本,各方面农艺性状较好的宁粳4号作为轮回亲本,通过回交和自交,并使用4个与qSS-9紧密连锁的分子标记Y-10、Y-11、Y-14、Y-13进行基因型的检测筛选,对宁粳4号进行耐贮性的遗传改良,获得了既耐贮藏、大多农艺性状又接近于宁粳4号的较为稳定的优良新品系,克服了宁粳4号耐贮藏性差的弱点。获得的新品系种子在人工老化和自然老化条件下均表现出发芽率明显提高、丙二醛含量显著降低、TTC染色效果更明显,表明转入耐储藏主效QTL Qss-9~(Kas)的宁粳4号新品系耐贮性显著提高。 相似文献
40.
随着国民经济不断发展,我国人民生活水平不断提升,多种人工作业逐渐被机器所取代。GPS/DR组合导航系统能够有效提升割草机器人定位精度,克服传统割草机器人固有弊端,提高工作效率。为此,对GPS/DR组合导航系统原理展开了分析,进行了GPS/DR组合导航系统割草机器人研究,并进行了相关试验研究,验证了GPS/DR组合导航系统割草机器人相对于传统割草机器人的优势。 相似文献