Viability of bifidobacteria in commercial yogurt products in North Carolina during refrigerated storage

Fifty-eight commercial yogurt products of seven brands (which claimed to include bifidobacteria) were obtained from local stores in Greensboro, North Carolina, USA. These products were examined at 0, 1, 2, 3 and 4 weeks for the viability of bifidobacteria and yogurt starter culture during refrigerated storage at 4°C. Our results showed that bifidobacteria counts were variable, ranging from 0 to 5.5 log cfu/mL. The average yogurt starter culture counts ranged from 5.20 to 8.87 log cfu/mL and 7.51–8.94 log cfu/mL for Lactobacillus delbrueckii spp. bulgaricus and Streptococcus thermophilus , respectively. Of the 58 products tested, only 44 products (76%) contained viable cultures. Viability of bifidobacteria in yogurt samples remained within the same levels during 3 weeks of storage at 4°C; however, the bacterial count started to decline during the fourth week. These results suggest optimal beneficial consumption of yogurt foods with live bifidobacteria should occur within 3 weeks of production. Results obtained from this research could be used by the industry to develop new technologies to ensure consumers receive high-quality products.     

EFFECTS OF SODIUM LACTATE, SODIUM ACETATE AND SODIUM DIACETATE ON MICROBIOLOGICAL QUALITY OF VACUUM-PACKED BEEF DURING REFRIGERATED STORAGE

Beef samples were cut into the pieces and treated with solutions of 1.8 and 2.5% sodium lactate (SL), 0.1% sodium acetate (SA), 0.1 and 0.2% sodium diacetate (SDA) and their combinations, packed under vacuum and stored in a refrigerator at 4C. Microbiological quality of the samples was investigated during their storage for 21 days. Sodium salts and their combinations significantly (P < 0.05) affected the aerobic plate count (APC). Although growth of lactic acid bacteria (LAB), psychrotrophs and coliforms was delayed in treated samples, they were not completely inhibited. The most effective treatment to delay the growth of microorganisms was the combination of 2.5% SL + 0.2% SDA. The count of bacteria of the samples reached and exceeded the spoilage limit (10⁷?10⁸log cfu/g) after 14 days at 4C.     

基于SVM的维吾尔文文本分类研究

文本自动分类技术在提高文本信息利用的有效性和准确性上具有重要的现实意义和广阔的应用前景。随着Internet上维吾尔文信息的迅速发展,维吾尔文文本分类成为处理和组织这些大量文本数据的关键技术。研究维吾尔文文本分类相关技术和方法,针对维吾尔文文本在向量空间模型表示下的高维性,本文采用词干提取和χ2统计量相结合的方法对表示空间进行降维。采用SVM算法构造了维吾尔文文本分类器。针对维吾尔文文本分类语料进行的实验结果表明,SVM分类器的MacroF1值达到了84.6%,明显好于kNN方法。     

大数据时代勘探云建设模式探索

按照大数据定义,油气勘探数据处理工作显然是一种大数据应用模式,而作为油气勘探核心工作平台的勘探云计算中心,其建设目的首先是为了满足企业内部业务数据处理工作需求,在确保计算力分享和协同工作的基础上,勘探云更注重数据存储、数据管理以及数据应用业务的支持,对照一般公用云建设模式,勘探私有云建设具备其独特的建设模式。笔者企业结合自身特点,对照当前大数据应用需求开展勘探私有云建设工作,取得了一定的效果,对企业主营业务的支持效果明显。     

Finding an optimization of the plate element of Egyptian research reactor using genetic algorithm

The second Egyptian research reactor ET-RR-2 went critical on the 27th of November 1997. The National Center of Nuclear Safety and Radiation Control （NCNSRC） has the responsibility of the evaluation and assessment of the safety of this reactor. The purpose of this paper is to present an approach to optimization of the fuel element plate. For an efficient search through the solution space we use a multi objective genetic algorithm which allows us to identify a set of Pareto optimal solutions providing the decision maker with the complete spectrum of optimal solutions with respect to the various targets. The aim of this paper is to propose a new approach for optimizing the fuel element plate in the reactor. The fuel element plate is designed with a view to improve reliability and lifetime and it is one of the most important elements during the shut down. In this present paper, we present a conceptual design approach for fuel element plate, in conjunction with a genetic algorithm to obtain a fuel plate that maximizes a fitness value to optimize the safety design of the fuel plate.     

Al掺杂锰酸锂材料在水系锂离子电池中的循环稳定性

水系锂离子电池具有优良的安全性能和高离子导电性等优点,得到了广泛研究.LiMn2O4材料在水系锂离子电池中较差的循环稳定性使其应用受到限制.为了改善这一缺陷,以乙炔黑为模板,采用简单的高温固相法合成了Al掺杂的LiMn2O4材料(LiMn1.9Al0.1O4),并应用于水系锂离子全电池中.实验结果表明,在0.1 A/g...     

融合奇异性和扩散过程的协同过滤模型

作为解决信息过载问题的有效方式,推荐系统能够根据用户偏好对海量信息进行过滤,为用户提供个性化的推荐。但在推荐过程中,性能表现优异的协同过滤模型并没有充分利用上下文信息,这在一定程度上使系统面临性能瓶颈。为了进一步提高系统性能,从评分上下文信息着手,通过对项目评分进行分类统计获得评分奇异性,同时借鉴多渠道扩散相似性模型将推荐系统作为用户-项目二分网络的思想,提出了融合奇异性和扩散过程的协同过滤模型(collaborative filtering model fusing singularity and diffusion process,简称CFSDP)。为了表明模型的优越性,比较实验基于MovieLens,NetFlix和Jester这3个不同的数据集展开。实验结果表明,该模型不仅具有良好的扩展性,而且在合理的时间开销下,可以显著提高系统的预测和推荐质量。     

气相纯化处理对碳纳米管修饰的XANES和XPS谱学研究

结合X射线近边吸收谱和光电子能谱对经过一系列纯化过程处理后的单壁碳纳米管进行系统的表征.这些纯化过程包括空气氧化、盐酸浸泡以及退火处理.从实验结果发现单壁碳纳米管的表面修饰程度在纯化过程中逐渐增强,经过Ar气保护下的高温退火后,这些表面修饰明显减少.同时还发现单壁碳纳米管能与氯原子成键,这种简单的修饰方法可能对单壁碳纳米管的应用具有重要意义.