Dynamics of Indigenous Microbial Populations of Butter Head Lettuce Grown in Mulch and on Bare Soil

ABSTRACT:  The native microflora of lettuce cultivated in mulch and on bare soil and its evolution during storage at optimal condition were evaluated. Inner, mid, and outer leaves of the lettuce heads were analyzed separately and the evolution of the microbial populations were fitted to Gompertz and logistic models. The cultivation method (bare soil and mulch) introduced differences in the initial counts, evolution, and tolerance to refrigeration temperatures for some of the microbial populations under study. Most microbial populations from mulch lettuce presented a decline or little growth under refrigerated storage. However, populations from bare soil lettuce presented some growth phase during storage. Lactic acid bacteria from bare soil lettuce presented significant growth after 8 d of storage while LAB from mulch grown lettuce did not. Concurrently with the LAB growth, there was a decline in the coliform counts in bare soil grown lettuce. At the end of storage, the inner and mid leaves of mulch lettuce presented lower counts of psychrotrophic bacteria, LAB, and yeast and molds.     

工程施工中混凝土裂缝成因分析与对策

介绍了混凝土的裂缝分类,从混凝土材料、预埋管线位置、温度、支座负筋移位、钢筋锈蚀、冻胀等方面分析了裂缝的形成原因,并给出了预防裂缝的方法及裂缝的常见补救方法,以减少混凝土裂缝的产生。     

Effects of flow on the fish communities of a regulated California river: implications for managing native fishes

We assessed the importance of flow regime to the success of native and non‐native fish species by analysing winter/spring seining data collected from 1987 to 1997 on the resident fish communities of the lower Tuolumne River, California. The data were analysed using regression models to predict the percentage of non‐native fish at a site. The regression models included various combinations of the variables longitudinal location of the site, mean April/May stream discharge in the year of sampling, and mean April/May stream discharge in the previous year. Comparison of the models indicated that the best model included longitudinal location and stream discharge in the previous year. This model is consistent with the hypothesis that flow in the previous year differentially affects reproductive success of native and non‐native species and thus the resulting community sampled in the following winter/spring. A detrended correspondence analysis of percentage abundance species data identified a co‐occurring group of native species and a co‐occurring group of non‐native species with the non‐native red shiner (Cyprinella lutrensis) grouping separately. The differing reproductive strategies of the species were consistent with the hypothesis concerning spawning success. Our results indicate that flow regime is an important determinant of the reproductive success of native and non‐native fish species in regulated rivers. Manipulations of flow regime are a potentially powerful tool for managing native fish species, but should be considered in combination with other restoration efforts and in the context of ecosystem restoration. Copyright © 2002 John Wiley & Sons, Ltd.     

细菌对红黏土抗剪强度的影响

为了探究土壤原生细菌对红黏土强度的影响,通过对红黏土中天然赋存的原生细菌进行富集培养,并在红黏土重塑试样中添加培养后的细菌菌液,通过土工试验和电镜试验分析红黏土物理力学性质和微观结构的变化。结果表明:随着细菌的掺入,三轴试样的破坏峰值和压缩模量都有所提高,并且随时间的增长,呈现先增大后减小的趋势;同时从电镜图像上来看,细菌的掺入使得红黏土中粉粒含量有所增加,相应的黏粒含量下降。研究结果可为进一步研究单一的细菌种类对红黏土物理力学性质和微观结构的影响提供参考。     

仿古也应有个性——藉大唐贡茶院设计而论

仿古有独创个性,加倍难。但可能:一是个性源于内涵,外化为形式。二是古今一体,恰因其难倒添个性。三是乡土化,不抄袭他处同时代先例。四为民间野趣中又含皇家礼仪。五是亟需提高社会对设计创新的尊重,不改变为一般化。     

全球化语境下对中国当代陶艺的反思

随着信息化时代的到来，全球化已经成为不可阻挡的趋势。在全球化的语境下，中国的当代艺术出现了一些问题：这其中包括：近现代以来西方哲学与美学的引进，造成了中国当代艺术理论的西方化趋势；现代艺术教育的发展。为中国艺术的发展创造了西方化的氛围；中国当代艺术与当代陶艺领域存在着严重的功利主义思想。加剧了当代艺术与当代陶艺的西方化。面对当代艺术与当代陶艺存在的这些问题，本文指出：全球化并不是指西方文化的一极化。而是一种多元文化交流与融合。艺术只有回归到民族文化与当代生活的现实中，才是全球化语境下当代艺术与当代陶艺的出路。     

云南某金矿选矿试验研究

针对云南某金矿石金以细粒、微细粒赋存于石英、黄铁矿的性质,在磨矿细度-74μm75%、T31为活化剂、丁基黄药与A25为捕收剂的条件下,采用一粗一扫两精的工艺流程,获得了金精矿品位79.30g/t,回收率89.45%的较好指标。     

计算机与话音通信集成中的应用程序接口技术

对现有的几类CTAPI的特性和关键技术进行了分析。在此基础上，针对目前国内ATM技术的广泛应用情况，提出了一种基于NativeModeATMAP的CTAPI开发基础，这对于CTI技术应用推广具有现实的意义。     

朝鲜族辣白菜制作方法

介绍了以白菜为原料生产朝鲜辣白菜的主要工艺。