Effects of Substitute Media on Development of Potted Cyclamen percicum Mill.

Five kinds of agricultural castoffs, such as sawdust and powder of coconut coir, were used as growing media to substitute the peat moss for potted Cyclamen percicum. It showed that most of the substitute media could fit for the growth of the root system without disturbing the spatial development of the root. The root activities of the plants in substitute media were all higher or not significantly lower than that in the contrast peat moss （PM）. The substitute media might not make adverse effects on the biosynthesis of chlorophyll of C. percicum leaves, and the nutrient components contained in the substitute media itself was none of the content of mineral elements in the leaves. The morphological indexes of C. percicum plants growing in the substitute media except in the powder of coconut coir （PCC） were all better than those in the contrast PM. The synthetically evaluation index of the plant showed that the sawdust, the powder of maize core, the powder of soybean stalk, the powder of peanut hull could take place the peat moss totally in C. percicum industrialization cultivation.     

干燥机粮层通风阻力特性数值模拟与试验

粮层内部通风阻力特性是影响干燥均匀性和能量损耗的关键因素之一。针对传统的经验公式存在精度偏低、未考虑粮层多孔介质的复杂变化因素和非线性的不确定性问题,基于传统的Ergun模型进行了压力损失因素分析;在通风阻力试验平台测定试验数据,通过探索性分析方法对风速进行分段,引入误差影响因子λ,导出了一种新的基于多孔介质Ergun的稻谷变层压力场模型;给出了优化阻力特性曲线,构建了变层阻力与层厚的数学关系。试验结果证实,风速小于0.2m/s时,λ取值为1;风速在0.2~0.4m/s范围内时,λ取值为0.89;风速在0.4~0.6m/s范围内时,λ取值为0.79。     

复式潜流湿地净化生活污水的试验研究

研究了新型复式潜流人工湿地对生活污水的净化效果。在不同水力负荷、季节、曝气方式等条件下经过小试试验,分析了该湿地对污染物净化效果的影响。结果表明,该系统出水水质稳定,达到《城镇污水处理厂污染物排放标准》(GB 18918-2002)的一级A标准。在水力负荷184 mm·d^-1条件下COD、NH₃-N去除率最大分别可达87.2%、68.9%。冬季低温条件下对各类污染物去除率仍大于20%。正交试验分析得知,最佳运行条件是气温28.6℃、水力负荷0.184 m³·m^-2·d^-1、水力停留时间2.4 d。对比试验表明,采用预曝气方式对湿地净化效果明显优于厌氧处理。     

Effect of different methods for the induction of spermiation on semen quality in European eel

Five hormonal treatments with human chorionic gonadotropin (hCG) were tested for the induction of maturation and spermiation in male farmed eels. The main aim was to optimize previously used hormonal treatments to achieve shorter induction treatments, longer spermiation periods and/or higher sperm quality. Fish treated for just 3 weeks (treatment E) or until the onset of spermiation (treatment C) showed the worst results, while the treatment consisting of weekly administration of 1.5 IU hCG g^?1 fish (treatment A) induced the highest percentage of spermiating males, the highest number of sperm samples and sperm volumes and densities similar to the rest of the treatments (B: half hormone dosage, or D: biweekly administration). Evaluation of the sperm quality was performed by computer‐assisted sperm analysis (CASA), considering the percentage of total motile spermatozoa, the percentage of fast and medium‐velocity spermatozoa, as well as different motility parameters. Sperm samples from A‐D groups showed between 44% and 54% motile spermatozoa, and between 10% and 15% fast spermatozoa, while samples from E‐treated males showed 0% motile cells. No significant differences were found in the spermatozoa straight line velocity (VSL), curvilinear velocity (VCL) or the angular velocity (VAP), neither spermatozoa beating cross frequency (BCF) between A–D groups.     

Fatty acid composition of 12 microalgae for possible use in aquaculture feed

Twelve algal strains representing the classes Cyanophyceae, Prymnesiophyceae, Bacillariophyceae, Rhodophyceae, Cryptophyceae, Chlorophyceae, Xantophyceae and Eustigmatophyceae were selected mainly from the culture collection of the Norwegian Institute for Water Research (NIVA). The algae were grown as continuous cultures in a 1.8 l. reactor, internally illuminated with an 11 W fluorescent tube. The retention time was adjusted in the range 2–4 days to fit the growth rate of the algae. The growth responses and fatty acid composition were analysed. The maximum production rate was obtained with Pseudokirchneriella subcapitata (0.63 g 1⁻¹ day⁻¹) and the lowest with Porphyridium cruentum 0.13 g 1⁻¹ day⁻¹. Arachidonic acid (AA) and eicosapentaenoic acid (EPA) were the dominating polyunsaturated fatty acids (PUFAs) in P. cruentum, while only EPA accumulated in Phaeodactylum tricornutum. Docosahexaenoic acid (DHA) was the major PUFA in Isochrysis galbana, while Pavlova sp. had both EPA and DHA. This is the first report on the fatty acid profiles of Nannochloropsis oceanica, Chroococcus sp., Synechococcus sp. and Tribonema sp.     

一种新型的流媒体系统设计与实现

介绍了一种适用于网络带宽不稳定环境下的高效、可扩展、自适应以及鲁棒性高的视频流压缩与传输技术,并以此为基础最终实现了一个流媒体系统。该系统由流媒体压缩和网络传输控制两部分组成,详细介绍了这两部分所采用的关键技术。     

栽培基质及配方施肥对虎雪兰‘霞光’的生长影响试验

通过盆栽方式，采用不同体积混合配比的泥炭、椰糠、陶粒、树皮基质试验，以N、P、K3元素3水平设置了正交施肥试验，测定植株的生长状况、叶片养分及发病情况，分析了不同栽培基质和施肥处理对‘霞光’生长特性的影响。结果表明，混合栽培基质对虎雪兰‘霞光’的生长较单一的基质效果好，以1／4树皮4-1／4泥炭＋1／4椰糠＋1／4陶粒混合基质植株的株高、假鳞茎、叶面积和根系生长效果最佳；外施氮、磷、钾肥最佳组合为N1P2K3，即NH4N03、NaH2P04和KCl含量分别为1．25mmol／L、0．456mmol／L和2．62mmol／L，有利于虎雪兰‘霞光’植株的营养生长，且设施栽培中发病率较低。     

Review on the roles and effects of growing media on plant performance in green roofs in world climates

Growing media (substrate) is a fundamental part of a green roof, providing water, nutrients and support to plants. However, little research has reviewed how it affects plant performances in different climatic regions. This study aims to analyse published research on green roof growing medium across world’s climate zones. Findings are structured according to Köppen–Geiger climate classification, aiming to investigate the prevalence of research conducted in different climate zones. Results from full-scale studies and laboratory or greenhouse experiments were reviewed. The later were included as they provide systematic knowledge on the effect of individual factors on system performances although cannot provide climate specific information. Studies discussed effects of major substrate components and depths on plant survival and establishment using standard test procedures. Results showed that most research in the subject were in temperate (group C climate classification), continental (group D) and dry climates (group B), respectively. Considerable number of investigations was conducted in controlled laboratory or greenhouse environments. Based on the results, future green roof research and guidelines should consider climate specifications of the region in designing growing medium, depths and attribute of green roof substrates in order to ensure enhanced plant performance. Especially, for more fragile but less investigated dry climate, considerations should be made to tackle heat fluctuations and drought stress by enhancing water holding capacity and thermal isolation of the substrate. To move forward, sustainable building solutions as a part of future urban forms, climate-adaptive green roof systems should be included into future research, practice and guidelines.     

论农民工的媒介素养教育

农民工是中国经济建设的主力军，他们是连接城乡二元社会的纽带，然而他们又是被社会忽略的群体，常常徘徊在媒体之外。在信息社会，掌握充分的信息资源意味着竞争力和财富，农民工作为中国经济的建设者应该全面提升自己的媒介素养从而提升自己的话语权，改变自己的社会地位。文中对农民工的媒介素养作了分析，并提出了加强农民工媒介素养教育的途径。     

猪的母性行为研究进展

母猪的母性行为包括分娩前后的一系列行为活动,例如做窝、哺乳以及抚育仔猪等。本文就母猪分娩前行为、分娩行为(产仔行为)、哺乳行为、护仔行为和念亲行为做一综述。