Observation on the cellular morphological and structural changes of Micromonospora purpurea in Fermentation process

对庆大霉素产生菌──绛红色小单孢菌发酵中细胞形态、结构变化进行了研究。扫描电镜观察，发现生长期细胞表面布满微小颗粒，生产期则形成较大突起。透射电镜观察到不同培养期细胞膜、细胞壁、细胞质、核区等超微结构都有明显变化。生长期细胞膜弯曲，胞壁薄厚不匀，核区、核糖体等清晰；生产期细胞膜与胞壁平行，胞壁变薄，出现横隔和间体。发现绛红色小单孢菌在生长期、生产期均形成横隔，提出在液体培养基中该菌以横隔方式进行繁殖。Cellular morphological and structural changes of M.purpurea(gentamicin producer)in Fermentation process were studied.Abundance of micro granules spread over the surFace of cells at trophophase,and transForm into larger protuberances at idiophase could be observed under the scanning electron microscope,while observation under the transmittance electron microscope,signiFicant changes of the plasmic membranes,cellwalls,cytoplasms,nuclear zone and other ultrastrtictures had taken place at diFFerent culture periods during the trophophase,and in the idiophase,winding of membranes,uneven thickness of cell walls and nuclear zone,as well as ribosomes became clear,cell wall became thin and parallel with the membranes,segnents and mesosomes are observed in this stage.Micromonospora purpurea produced segments in both phases,the authours proposed that in liquid medium Fermentation,the strain diFFerentiation process Followed the segment mode

近30年来高邮湖(含邵伯湖)自然水域面积变化及其影响因素

湖泊水域面积变化特征反映气候与人类活动对湖泊生态系统结构与功能的影响,对湖泊健康评价与水生态修复有重要指导价值.以1988—2015年8期Landsat TM ETM+遥感影像为数据源,综合运用目视解译法与比值阈值法提取了研究区高邮湖(含邵伯湖)及其围网养殖区的边界信息,分析了研究区水域面积变化特征及其影响因素.结果表明:①1988—2015年研究区自然水域面积呈现前期持续缩小、近期部分恢复的阶段性变化趋势.其中,1988—2000年自然水域面积缓慢缩减,平均减小速率为4.08 km^2 a;2000—2011年迅速缩减,平均减小速率为12 km^2 a;2011—2015年迅速增长,自然水域面积增加108 km^2;1988年自然水域面积最大(716 km^2),2011年最小(535 km^2),2015年部分恢复(643 km^2).②1988—2015年流域内年均降水量先减后增,年均气温逐渐升高.年均气温升高与自然水域面积变化具有相关性(R 2=0.472);年均降水量则与自然水域面积变化无明显关联(R^2=0.118).③1988年和1992年研究区内未见明显的围网养殖,2000年围网养殖区面积仅为45 km^2,2011年最大,达199 km^2.2000—2009年和2009—2015年围网养殖区面积平均增长速率分别为15.56和9.00 km^2 a;北部湖区围网养殖集中,自然水域面积变化最为显著,东西湖区次之.研究显示,1988年以来,年均气温和围网养殖对高邮湖自然水域产生了显著影响,湖区北部湿地侵占严重,湿地生态屏障功能下降

Prediction of Energy Resolution in the JUNO Experiment

International audienceThis paper presents the energy resolution study in the JUNO experiment, incorporating the latest knowledge acquired during the detector construction phase. The determination of neutrino mass ordering in JUNO requires an exceptional energy resolution better than 3% at 1 MeV. To achieve this ambitious goal, significant efforts have been undertaken in the design and production of the key components of the JUNO detector. Various factors affecting the detection of inverse beta decay signals have an impact on the energy resolution, extending beyond the statistical fluctuations of the detected number of photons, such as the properties of liquid scintillator, performance of photomultiplier tubes, and the energy reconstruction algorithm. To account for these effects, a full JUNO simulation and reconstruction approach is employed. This enables the modeling of all relevant effects and the evaluation of associated inputs to accurately estimate the energy resolution. The study reveals an energy resolution of 2.95% at 1 MeV. Furthermore, the study assesses the contribution of major effects to the overall energy resolution budget. This analysis serves as a reference for interpreting future measurements of energy resolution during JUNO data taking. Moreover, it provides a guideline in comprehending the energy resolution characteristics of liquid scintillator-based detectors