复合磷酸盐对鲜切牛肉肌球蛋白凝胶保水性的影响

研究了焦磷酸钠(SAP)、三聚磷酸钠(STP)、六偏磷酸钠(HMP)及复合磷酸盐对牛肉肌球蛋白凝胶保水性的影响。结果显示,当复合磷酸盐中SAP,STP和HMP的质量比为2∶1∶1,添加量为0.2%时,可获得最佳的感官品质和较好的凝胶保水性,影响凝胶保水性因素的主次顺序为SAP>HMP>STP,且SAP和HMP对凝胶保水效果具有显著影响。     

基于车载三维激光雷达的玉米点云数据滤波算法

为支持表型参数测量和数字植物相关研究,对车载三维激光雷达获取的玉米点云数据进行分析处理,提出了一种基于统计分析的两次滤波算法。以大喇叭口期的京农科728和农大84玉米为研究对象,使用VLP-16型三维激光雷达采集田间玉米点云数据;对点云数据进行直通滤波预处理,去除无关点后,进行第1次点云数据滤波处理,设置精确率和召回率阈值,选取参数组合;再对点云进行第2次滤波处理,确定精确率和召回率最优组合(110,0. 9)、(6,1. 2),边际组合(100,1. 0)、(6,1. 2)和(110,0. 8)、(5,0. 9),共3组参数组合;以3组验证集数据进行测试,结果表明:最优组合性能最优,可在京农科728和农大84玉米点云数据滤波中通用。     

基于结构光三维点云的棉花幼苗叶片性状解析方法

针对传统的棉花叶片表型测量方法主观、低效,对复杂性状如卷叶程度、黄叶占比等很难量化的问题,提出一种基于结构光三维成像的棉花幼苗叶片性状解析方法。首先,采用结构光扫描仪获取棉花幼苗的三维点云数据;然后,利用直通滤波、超体聚类、条件欧氏距离算法,实现叶片点云的识别与分割;最后,基于分割的叶片点云,采用三角面片化、随机采样一致性、Lab颜色分割等处理,实现叶片面积、周长、生长角度、卷曲度、黄叶占比等参数的快速、准确、无损提取。对40株棉花幼苗进行三维结构光成像试验,结果表明,3D叶片面积、周长测量的平均绝对误差分别为2. 59%、2. 85%,具有较高的测量精度,还证明叶片卷曲度和黄叶占比能显著区分病叶和正常叶。     

Japanese sardine (Sardinops melanostictus) mortality in relation to the winter mixed layer depth in the Kuroshio Extension region

A drastic population change in Japanese sardine (Sardinops melanostictus) has been noted as being related to winter sea surface temperature (SST) in the Kuroshio Extension region. The former studies suggest two possible explanations. One is that temperature itself affects sardine. The other is that SST represents the environmental change of the Kuroshio Extension region and other causes directly affecting sardine. In this study, we found that sardine mortality from post‐larva to age 1 negatively correlated with the winter mixed layer depth (MLD) in the Kuroshio Extension region from 1979 to 1993. During the period of a deep winter mixed layer (during the early 1980s), sardine mortality was low, whereas mortality was high when the winter mixed layer was shallow (during the late 1980s to early 1990s). By using a lower trophic‐level ecosystem model forced by the observed time series of MLD, SST, light intensity and nutrient data, we found that the estimated spring zooplankton density drastically varies from year to year and has a significant negative correlation with sardine mortality. The inter‐annual variation of spring zooplankton density is caused by the winter MLD variation. During the deep winter mixed layer years, a phytoplankton bloom occurs in spring, whereas during the shallow winter mixed layer years, the bloom occurs in winter. The results of our study suggest that the decline in the Japanese sardine population during the late 1980s to early 1990s was due to an insufficient spring food supply in the Kuroshio Extension region where sardine larvae and juvenile are transported.     

2株毒死蜱降解菌的分离鉴定及其混合降解特性研究

从生产毒死蜱农药厂采集的活性污泥中分离筛选得到2株降解效率较高的毒死蜱降解菌,命名为D1、D3,根据表型特征、生理生化特性和16 S rRNA基因序列相似性分析,将其鉴定为苍白杆菌属(Ochrobactrum sp.)和副球菌属(Paracoccus sp.)细菌。2株菌以最佳配比(1∶1.25)混合施用时,与单菌相比,毒死蜱降解效率可提高12%~26%;以混合菌株为研究对象,发现其对毒死蜱最适降解温度为30℃,最适降解pH值为7.0,最适NaCl浓度为0.5%;混合菌株施入土壤后,可保持较高的定殖能力和降解效率。     

Mixed cropping with ice plant alleviates the damage and the growth of cowpea under consecutive NaCl treatment and after the recovery from high salinity

We investigated the alleviative effects of mixed cropping using ice plant, which is one of the salt-accumulating halophytes, on the damage and growth inhibition of cowpea, which is not tolerant to high salinity. Three cropping patterns (mono cropping of cowpea and ice plant and their combination) were tested. The plants were treated with 0, 100, 200 and 300 mM NaCl for 14 days (consecutive NaCl). The plants were also treated with NaCl for 3 days, followed by 2 weeks (short-term recovery) and 1 month (long-term recovery) recovery. Salinity levels for short-term recovery were similar to those of the consecutive experiment, while the concentration of long-term recovery was 250 mM. The alleviative effects of mixed cropping in the consecutive NaCl experiment were observed at 200 and 300 mM NaCl. Mixed cropping significantly reduced the Na content in the cowpea leaves at 200 and 300 mM NaCl compared with mono cropping. In addition, the Na content in the soil of mix-cropped cowpea at 200 and 300 mM NaCl was statistically lower than that of the mono cropping. Mixed cropping was effective to recover from high concentration of NaCl in the experiments of short- and long-term recovery. These results indicate that mixed cropping with a halophyte could be effective in mitigating the damage and growth inhibition of a glycophyte not only under salinity but also under recovery periods.     

Drivers of Setaria pumila (Poir.) Roem. et Schult growth and impact on forage quality in lowland Switzerland meadows

Invasive grasses (especially Setaria pumila (Poir.) Roem. et Schult) increasingly threaten meadows and pastures as a consequence of human impact and climate change. We conducted a study in 2012 and in 2013 to better understand the growing cycle and the influence of S. pumila on forage quality of lowland meadows. We observed a rapid increase of S. pumila presence and phytomass on the southern side of the Alps across the growing season. We measured (i) above‐ground phytomass, with a modified Corral‐Fenlon method; (ii) botanical composition using the linear point quadrat method; and (iii) grassland chemical composition by NIRs (near‐infrared spectroscopy) analyses. To test the hypothesis that S. pumila summer growth is related to specific climatic conditions, meteorological data (temperature, precipitation and evapotranspiration) were collected from meteorological stations near the study sites. Total phytomass was sorted into S. pumila and other species. We used a generalized linear mixed models (GLMM) and found the abundance of S. pumila to be inversely correlated with rainfall and the presence of other species, but positively correlated with temperature increase. The increase of S. pumila above‐ground phytomass production was linked to a reduction of forage quality.     

Silage and total mixed ration hygienic quality on commercial farms: implications for animal production

Implications of silage hygienic quality for animal production were investigated on forty‐five dairy farms in South West England. Samples of grass and maize silages and of total mixed rations (TMR) were obtained together with information on silage technology, herd size and animal production. Samples were analysed for mycotoxins, bacteria, yeasts, moulds and chemical composition. Thirteen mycotoxins were assayed, but none were detected in the samples of grass silage. However, mycotoxins were found in 0·9 of all maize and other silage samples, with deoxynivalenol and zearalenone predominating. There was no relationship between total mycotoxin concentration and mean lactation milk yield per cow. Enterobacteria counts tended to be higher in maize silage than in grass silage and higher still in TMR – a cause for concern. There were no relationships between mould counts and mycotoxin concentrations in silages, implying that mycotoxins may have been produced in the field pre‐ensiling.     

斜流泵小流量工况压力脉动数值模拟与实验

基于标准的Smagorinsky亚格子尺度模型,对斜流泵全流场进行大涡模拟并结合压力脉动实验对小流量工况下的压力脉动和内部流场进行研究。实验结果表明,叶轮进口处的脉动幅值最高,随着流量的降低压力脉动幅值逐渐增加,不同工况下叶轮进口、叶轮出口、导叶进口的压力脉动主频为叶频,但导叶出口脉动主频随着流量的变化而变化。大涡模拟表明,0.8Qopt工况下叶轮进口流动状态较好,叶轮进口轴面速度变化较小,而在0.4Qopt工况下叶轮进口流动状态较复杂,轴面速度变化较大,0.4Qopt工况时叶轮进口冲角增加以及受到相邻叶片叶顶泄漏流的影响,在t*=0.041 6时叶片进口吸力面已发生流动分离,当叶轮从t*=0.041 6旋转到t*=0.124 9时,叶片吸力面流动分离加剧,轮缘处的轴面速度明显升高,同时分离涡的旋转强度也逐渐增强,导致该区域的静压下降,逆压梯度上升,促使回流的产生,当回流到达叶片进口时进口处的静压逐渐恢复,因此叶轮进口流动分离是引起叶轮进口压力脉动幅值增加的重要因素。     

江苏省空中云水资源评估

研究旨在定量化评估江苏省空中云水资源可开发量及基本特征。根据云水收支方程,将参与大气云水循环且未降落到地面的资源定义为空中云水资源。利用1981—2010年EAR-Interim高分辨率再分析资料的风场及云含水量,计算江苏上空云水资源年均总量、时空特征及变化趋势。结果表明,资源年均总量353.1亿t,春夏季偏多,秋冬季偏少,开发潜力巨大。旱期(缺水期)沿淮淮北最多,达70.8亿t,沿海垦区、苏南环太湖次之;非旱期总量约占全年58.3%。近30年,云水资源呈下降趋势,平均每10年减少18亿t。建议加大开发力度,实现常态化开发利用,率先建立淮北、沿海、环太湖开发利用重点作业区,加强开发利用技术研究,提高开发效率。