油菜宽幅折叠式浅旋精量联合直播机设计与试验

针对长江中下游稻油轮作区油菜播种作业工序复杂、效率低的问题,设计了一种油菜宽幅折叠式浅旋精量联合直播机,可实现开畦沟、浅旋灭茬、油菜精量播种、种床覆土等功能。分析确定了整机基本结构和工作过程,对液压折叠机构进行了运动学和动力学分析,利用Matlab软件确定了液压缸结构参数以及承受的最大负载,基于拖拉机液压油路设计了液压折叠控制系统;根据开畦沟深度、宽度、耕深、覆土均匀性等作业要求,确定了刀轴转速为360～480 r/min,开沟刀、浅旋刀辊旋转半径分别为320、175 mm,开沟刀盘开沟刀数量为8;分析了分土导流板结构参数的取值范围,应用EDEM软件开展了分土导流板不同结构参数组合下的覆土均匀性正交试验,建立了覆土均匀性与分土导流板安装距离、导流板长度和分土板角度的回归数学模型,试验结果表明,当分土导流板安装距离为200 mm、导向板长度为600 mm、分土板角度为60°时,覆土均匀性可达93.33%。田间试验结果表明,当机组前进速度为3.6 km/h、畦沟深度为150 mm、刀轴转速为480 r/min时,油菜宽幅折叠式浅旋精量联合直播机作业后种床碎土率为91.62%,秸秆埋覆率为9...     

基于纹理-颜色特征与植被指数融合的冬小麦LAI估测

准确、快速、无损估测叶面积指数(LAI)对于冬小麦生产管理具有重要意义。利用无人机搭载Prime ALTUM多光谱相机获取冬小麦拔节期、孕穗期、抽穗期、灌浆期多光谱图像,利用LAI-2200C型植物冠层分析仪获取地面LAI数据。通过Pearson相关性分析筛选出25个植被指数,并提取植被指数影像中8种纹理特征：对比度(CON)、熵(ENT)、方差(VAR)、均值(MEA)、协同性(HOM)、相异性(DIS)、二阶矩(SEM)和相关性(COR),以及3种颜色特征：一阶矩(M)、二阶矩(V)和三阶矩(S),再分别利用多元逐步回归模型(MSR)、支持向量回归模型(SVR)和高斯过程回归模型(GPR)构建冬小麦LAI估测模型。结果表明：相对于考虑单一类型变量,考虑结合纹理特征和颜色特征进行估测时模型精度更高;3类模型中,GPR模型估测冬小麦LAI的精度最高;所有模型中,基于纹理-颜色特征与植被指数融合的GPR模型估测冬小麦LAI精度最高(决定系数R²为0.94,均方根误差(RMSE)为0.17 m²/m²,平均绝对误差(MAE)...     

基于改进ResNeXt50残差网络的锦鲤选美方法

锦鲤选美的不同等级之间具有高相似度的特点,目前都是人工进行选美分级。为解决人工选美所存在的效率低、主观性强、成本高的问题,提出了一种基于迁移学习和改进ResNeXt50残差网络的锦鲤选美方法。本文首先构建了红白、大正、昭和3种锦鲤的选美等级数据集。其次,采用迁移学习策略提高训练速度,并从SE注意力模块、Hardswish激活函数和Ranger优化器3方面对ResNeXt50模型进行了改进,构建了SH-ResNeXt50锦鲤选美分级模型。试验结果表明：SH-ResNeXt50模型有效提升了锦鲤选美的等级分选能力,模型准确率达95.6%,损失值仅0.074,优于常用的AlexNet、GoogLeNet、ResNet50和ResNeXt50网络模型。最后,采用Grad-CAM分析SH-ResNeXt50模型的可解释性,结果表明SH-ResNeXt50模型和人工识别的感兴趣区域基本一致。本文所提出的方法实现了具有高相似度的锦鲤不同等级的智能分选,对其它具有高相似度的生物等级分选具有借鉴意义。     

Detection of land animal remains in fish meals by the polymerase chain reaction-restriction fragment length polymorphism technique

In the present study a technique was developed with the aim of guaranteeing the composition and security of fish meals, since it allows verification of whether these meals contain land animal remains. The method is based on polymerase chain reaction (PCR) and length polymorphism, followed by a restriction fragment length polymorphism (RFLP). Specific primers for every species were designed and calibrated, generating exclusively a PCR product with a specific size when DNA for each species was present in the sample. This technique allows the detection of land animal remains in fish meals, specifically cow, chicken, pig, horse, sheep, and goat. The identity of the PCR products can be confirmed by RFLP analysis using only one restriction enzyme. The selected restrictase generated one characteristic restriction profile for every species included in this study. The detection limit of this method was calculated by using mixtures of fish meals in different proportions and meal that exclusively contained remains of one of these land species studied. The analytical strategy herein proposed was applied to fish and meat meals, giving good results, both in the analyzed standards and in commercial samples.     

Grape-seed procyanidins act as antiinflammatory agents in endotoxin-stimulated RAW 264.7 macrophages by inhibiting NFkB signaling pathway

Procyanindin extract (PE) is a mixture of polyphenols, mainly procyanidins, obtained from grape seed with putative antiinflammatory activity. We evaluated the PE effect on RAW 264.7 macrophages stimulated with lipopolysaccharide plus interferon-gamma that show a rapid enhanced production of prostaglandin E2 (PGE2) and nitric oxide (NO). Our results demonstrated that PE significantly inhibited the overproduction of NO, dose and time dependently. PE caused a marked inhibition of PGE2 synthesis when administered during activation. Moreover, PE pretreatment diminished iNOS mRNA and protein amount dose dependently (10-65 microg/mL). PE (65 microg/mL) pretreatment inhibited NFkappaB (p65) translocation to nucleus by nearly 40%. Trimeric and longer oligomeric-rich procyanidin fractions from PE (5-30 microg/mL) inhibited iNOS expression but not the monomeric forms catechin and epicatechin. Thus, we show that the degree of polymerization is important in determining procyanidin effects. PE was considerably a more effective inhibitor of NO biosynthesis (IC50 = 50 microg/mL) in comparison to other antiinflammatories, such as aspirin (3 mM), indomethacin (20 microM), and dexamethasone (9 nM). In conclusion, PE modulates inflammatory response in activated macrophages by the inhibition of NO and PGE2 production, suppression of iNOS expression, and NFkB translocation. These results demonstrate an immunomodulatory role of grape seed procyanidins and thus a potential health-benefit in inflammatory conditions that exert an overproduction of NO and PGE2.     

Selective modification of clay minerals for the adsorption of herbicides widely used in olive groves

Ground and surface water contamination by herbicides applied to olive groves in Spain and other Mediterranean countries is demanding strategies to prevent and remediate the environmental problems repeatedly caused by such herbicides. In this study, six different organic cations (L-carnitine, spermine, hexadimethrine, tyramine, phenyltrimethylammonium, and hexadecyltrimethylammonium) were incorporated into Na-rich Wyoming montmorillonite (SWy-2) and Ca-rich Arizona montmorillonite (SAz-1) at two different loadings (50% and 100% of the cation exchange capacity of the clays) as a strategy to enhance the affinity of the clay minerals for three herbicides widely used in olive groves: terbuthylazine, diuron, and MCPA. The modified montmorillonites were characterized and tested as adsorbents of the herbicides through batch adsorption tests. At the experimental conditions used, some of the modified montmorillonites removed more than 95% of the herbicide initially present in aqueous solution, whereas the unmodified clays removed less than 15%. All three herbicides displayed very strong affinities for SAz-1 exchanged with hexadecyltrimethylammonium cations, particularly when these were incorporated at 100% of the cation exchange capacity of the clay mineral. Terbuthylazine and diuron also displayed very strong affinities for SWy-2 exchanged with L-carnitine and spermine, respectively. The chemical characteristics of the organic cation greatly influenced the adsorptive properties of the resultant organoclay. The herbicides were in general reversibly adsorbed by the modified clays. The results indicate that some of the tested modified clays could be suitable for the removal of the assayed herbicides from contaminated water and also as possible supports for the design of slow release formulations of such herbicides to attenuate their environmental impact when used in high-risk scenarios such as olive groves.     

Changes in the volatile composition of a semihard ewe milk cheese induced by high-pressure treatment of 300 MPa

The effect of high-pressure (HP) treatment (300 MPa, 10 min) on the volatile profile of semihard ewe milk cheeses was investigated. The HP treatment was applied at two different stages of ripening (1 and 15 days; 3P1 and 3P15) and microbiota, proteolysis indexes (soluble nitrogen and total free amino acid content), and volatile compounds were assayed at 15, 60, 90, and 150 days of ripening. The intensity of odor and aroma of cheeses was also assayed. 3P1 cheeses presented the highest content of free amino acids and were characterized by the lowest amounts of aldehydes, ketones, short-chain free fatty acids, and terpenes and higher levels of ethanol and ethyl esters. 3P15 cheeses were characterized by the highest content of short-chain free fatty acids and pyruvaldehyde and the lowest abundance of secondary alcohols and were more similar to control cheeses than those HP-treated on the first day. Intensities of odor and aroma were not significantly influenced by the HP treatment. However, the panellists found some differences in 3P1 as compared with control and 3P15 cheeses in what they perceived as lower odor and aroma quality.     

南水北调东线徐州段水环境现状及其污染防治对策

对南水北调东线徐州段7个控制断面2004年水质监测结果进行评价分析,结果表明,水质达标率仅为42.9%,水体污染以耗氧性污染物和氨氮为特征的有机污染为主。结合当地实际,分析了南水北调东线徐州段水质超标的原因,并根据当地经济、自然特征,提出了针对性较强、切实可行的水污染防治对策和措施。     

肉牛自动化无应激动态称重系统的设计与试验

【目的】牛只体重数据是衡量牛体健康生长发育的重要指标,定期对牛只称重对实施精细化养殖有重要意义。【方法】采用带围栏的地磅称重、月龄推算、体尺估算测量以及采用保定架等方法对肉牛进行静态称重。【结果】可以实现肉牛全程无障碍通过,在肉牛自然行走状态下监测出肉牛体重信息,有效避免了肉牛产生应激反应;称重效率高,系统锁定肉牛有效体重数据在2~4 s。平均每头牛从进入通道排队到称重结束,时间在10 s之内。肉牛速度较快通过称重平台时,误差在0.5%以下;肉牛在行走—停顿运动状态和平稳行走运动状态下,误差在0.2%以下。【结论】肉牛无应激自动化动态称重系统,主要由主体机械结构框架、RFID无线射频识别系统、供电系统、称重系统、数据传输5部分组成。     

广东省鸭疫里默氏杆菌流行病学监测及遗传进化关系

【目的】明确广东地区鸭疫里默杆菌Riemerella anatipestifer的血清型、耐药状况及遗传进化关系。【方法】从规模化鸭场分离鉴定鸭疫里默氏杆菌,通过玻片凝集试验鉴定血清型;利用试管两倍稀释法测试抗菌药物的最低抑菌浓度,分析药物的敏感性;采用全基因组测序技术分析序列特征并构建核心基因组遗传进化树。【结果】共分离鉴定鸭疫里默氏杆菌168株,血清1、2、3、5、6、7、8、10型均有流行,血清1型的菌株高达54.17%(91/168),其次为2型,占27.97%(47/168)。48株代表性菌株对庆大霉素、卡那霉素、盐酸环丙沙星表现高度耐药,耐药率均超过80%;对土霉素、盐酸四环素、盐酸金霉素、氧氟沙星、诺氟沙星、磺胺二甲嘧啶、磺胺对甲氧嘧啶的耐药率均在60%以上;对阿莫西林、头孢噻肟和大观霉素的耐药率低于30%。受试菌株对5～12种药物耐药,共有44种耐药谱型。成功获得46株菌株全基因组序列,共检出6种耐药基因,其中,耐药基因erm(F)和tet(X)的检出率较高,分别为73.91%(34/46)和82.60%(38/46),同时携带2种以上耐药基因的菌株占95.65%(44...