应用液态悬浮芯片技术建立17种大肠杆菌耐药基因多重快速检测方法

为建立一种快速、高通量的多重耐药基因检测方法,利用Luminex液态芯片平台,建立了可同时检测17种耐药基因的液态芯片检测方法.该方法对大肠杆菌常见的七大类抗菌药物所对应的17种耐药基因(blaSHV、blaCMY-1、Aph3-IIa-1、aac(6)-Ib-cr、aadA-1、cmlA-1、gyrA、mcr-1、N...     

重组逆转录病毒介导的肿瘤坏死因子基因转移与哺乳动物细胞表达

以构建的重组肿瘤坏死因子逆转录病毒载体ｐＺＩＰＴＮＦ ＤＮＡ转染Ｃｏｓ７细胞，获得了ＴＮＦα暂时性表达。采用ＤＮＡ－磷酸钙共沉淀法，将ｐＺＩＰＴＮＦ ＤＮＡ导入了单向性逆转录病毒包装细胞ψ２，在Ｇ４１８选择下，克隆出了ψ／ｐＺＩＰＴＮＦ细胞系。该细胞可产生重组ＴＮＦ逆转录病毒。本研究利用ψ／ｐＺＩＰＴＮＦ细胞分泌的重组逆转录病毒连续传代感染ψ２或ＰＡ３１７细胞以及病毒交替感染ψ２和ＰＡ３１７细胞，     

基于融合坐标信息的改进YOLO V4模型识别奶牛面部

为实现奶牛个体的准确识别,基于YOLO V4目标检测网络,提出了一种融合坐标信息的奶牛面部识别模型。首先,采集71头奶牛面部图像数据集,并通过数据增强扩充提高模型的泛化性能。其次,在YOLO V4网络的特征提取层和检测头部分分别引入坐标注意力机制和包含坐标通道的坐标卷积模块,以增强模型对目标位置的敏感性,提高识别精度。试验结果表明,改进的YOLO V4模型能够有效提取奶牛个体面部特征,平均精度均值为93.68%,平均帧率为18帧/s,虽然检测速度低于无锚框的CenterNet,但平均精度均值提高了10.92%;与Faster R-CNN和SSD模型相比,在检测速度提高的同时,精度分别提高了1.51和16.32个百分点;与原始YOLO V4相比,mAP提高0.89%,同时检测速度基本不变。该研究为奶牛精准养殖中的牛脸图像识别提供了一种有效的技术支持。     

浅谈动科专业课程多媒体教学中存在的问题与对策

多媒体技术作为一种全新的教学手段走进课堂。本文阐述了动科专业课程多媒体教学的优越性,分析了存在的问题,同时提出一些建议,以期望能充分发挥多媒体技术的优点,更好的提高动科专业课程的教学效果。     

A genetic linkage map in southern‐by‐spring oat identifies multiple quantitative trait loci for adaptation and rust resistance

We developed 178 recombinant inbred lines from a southern‐by‐spring oat population designated as “TxH.” These lines were genotyped to generate a high‐quality linkage map that resolved 6,902 markers into 21 linkage groups that matched closely with the latest hexaploid oat consensus map. Three major quantitative trait loci (QTLs) affecting heading date were found in locations that are consistent with known QTLs and candidate genes, and two other QTLs affecting heading date were found in novel locations. Five QTLs affecting plant height were found. Both sets of QTLs are responsible for transgressive segregation observed for these two traits. Four QTLs affecting resistance to crown rust, caused by the pathogen Puccinia coronata f. sp. avenae, were identified. Two of these QTLs are consistent with known clusters of rust resistance genes, while two may represent new locations of novel rust resistance genes. A complete set of SNP sequences suitable for generating markers for molecular selection is provided.     

汶川地震灾区泥石流危险性评估——以都江堰—汶川公路为例

公路泥石流危险性评估是震区道路交通防灾减灾和重建规划的重要基础性技术工作之一.选取都江堰—汶川公路沿线28条泥石流沟为研究对象,运用遥感和GIS技术进行数据处理与综合分析,采用灰色关联分析法进行评价因子遴选和权重确定,进行各条泥石流沟危险度计算,完成震区都江堰—汶川公路沿线泥石流危险性评估.结果表明:1)都江堰—汶川公路沿线28条泥石流沟大部分处于高度危险以上、占总数的78.57％,极高危险区占总数的25％;2)饵沟、牛圈沟、磨子沟危险性最大,其次是高店子沟、马埝坪沟和一碗水沟;3)基于灰色关联分析法的多因素评价方法,能较好地确定评价因子及其权重、并计算出泥石流危险度,具有一定实用性.研究结果可为灾区防灾减灾管理、灾后恢复重建和道路交通选线设计提供必要的依据和参考.     

"三明三暗"问题对水土保持监督执法影响的探讨

依法行政,要求行政机关及行政执法人员,既要作为,又不能滥用职权;既要到位,又不能越位;既要不越位,又不能缺位。但由于种种原因,行政机关及工作人员,具体行政行为存在明作为,暗不作为;明到位,暗不到位;明不越位,暗越位的现象。笔者就“三明三暗”问题对水土保持监督执法的影响以及解决的途径进行了探讨。     

控释氮肥运筹对钵苗摆栽籼粳杂交稻甬优1540产量及氮肥利用的影响

研究籼粳杂交稻钵苗摆栽超高产栽培模式下适宜的控释氮肥运筹。试验于2016—2017年在安徽庐江进行,以当地高产籼粳杂交稻甬优1540为供试品种,设置控释氮肥一次性基施(single basal application of CRNF, BC)、与尿素分蘖肥配施(basal application of CRNF combined with urea top-dressing at the tillering stage, BC+TU)、与尿素穗肥配施(basal application of CRNF combined with urea top-dressing at panicle initiation, BC+PU)三种运筹模式,以尿素分次施肥(conventional high-yield fertilization,SU)和不施氮肥(0N)为对照,研究控释氮肥运筹对钵苗摆栽籼粳杂交稻产量、氮肥吸收利用及相关农艺指标的影响。结果表明,控释氮肥阶段释放基蘖肥:穗肥比例为7∶3,较传统优化氮肥运筹SU (6∶4)整体表现基蘖肥冗余,穗肥不足,因而BC和BC+TU处理显著降低了钵苗摆...     

Effect of salinity on the decomposition of soil organic carbon in a tidal wetland

Purpose

Climate warming and sea level rise have the potential to change the salt level of soil in tidal wetlands. And it is important to clarify the process and the mechanism of decomposition of soil organic carbon in a tidal wetland under varying salinities. The aim of this study was to evaluate the impacts of soil salinity on the decomposition rate of organic carbon (DROC) and dissolved organic carbon (DOC) in a tidal wetland.

Materials and methods

Two types of soil (surface soil in Suaeda salsa and bare tidal flat) were collected, air-dried, and homogenized. After adding different content of salt (0 g/L, 3 g/L, 6 g/L, 9 g/L, and 12 g/L), the soils were incubated for 28 days at stable room temperature (25?±?2 °C) and added by deionized water to maintain the stability of soil moisture. The gases (CO₂ and CH₄) emission rates of each salt treatment were measured during 28-day incubation. DROC was determined by the sum of daily CO₂-C emission rates and daily CH₄-C emission rates in this study.

Results and discussion

Salt addition inhibited the process of gas emissions and DROC. Gases emission rates and DROC of two types of soil showed similar temporal trends, with distinctive drop in the beginning of experiment and no significant decrease followed. Significant difference of DOC among salt treatments was found in the bare tidal flat soil. Variations of partial correlation between DROC and soil salinity and DOC showed similar trends (e.g., in days 9–18, the positive effect of DOC on DROC was greatly promoted (R²?=?0.80, p?<?0.001), and the negative effect of soil salinity was highly improved (R²?=?0.93, p?<?0.001)). Soil properties, in particular DOC, may be primary factors accounting for the discrepancy of gases emission rates and DROC of two types of soil.

Conclusions

Increased soil salinity had a negative effect on DROC during 28-day incubation. The impact of soil salinity and DOC on DROC were varied in different phases of laboratory experiment (soil salinity generally had increasingly negative relationship with DROC, but DOC showed most significantly positive relationship in the middle stage of incubation). Both the formation and consumption of DOC may be valuable for more detail research regarding to decomposition of soil organic carbon.

     

摩天岭北坡东南部不同海拔梯度草本植物群落特征

海拔因子是影响植被生长的主导因子,对生态系统格局与过程有着深远的影响。本研究运用相关分析、逐步回归分析和Pearson相关系数检验对摩天岭北坡南段海拔600-1 500m草本植物多样性以及群落初级生产力进行分析。结果表明,1)物种多度与海拔梯度呈显著正相关关系(R2=0.278 4)(P0.05),植物盖度与海拔梯度呈显著负相关关系(R2=0.43),草本层高度、密度与海拔梯度相关性不显著(P0.05);2)植被地上生物量随海拔梯度的上升表现出先增后减的变化趋势,地下生物量随海拔变化差异较大,表现出先增后减再增的趋势;3)从功能群的角度分析,草本层植物功能群地上生物量和地下生物量随海拔梯度的变化趋势基本一致。摩天岭北坡东南部草本植物群落特征随海拔梯度变化显著,各功能群的地上、地下生物量差异显著。生物量与草本层植被盖度呈极显著正相关(P0.01),生物量与植物高度和密度的相关性不显著,以及植物盖度、高度和密度之间相关程度不高。