Microbial source tracking using host specific FAME profiles of fecal coliforms

The objective of this study was to investigate the host-specific differences in fatty acid methyl ester (FAME) profiles of fecal coliforms (FC). A known-source library was constructed with 314 FC isolates cultured from 6 possible sources of fecal pollution; 99 isolates from sewage; 29 from bovine; 29 from poultry; 50 from swine; 46 from waterfowl; and 61 from deer. It was found that the hydroxy FAMEs 12:0 2 OH, 12:03 OH, and 14:02 OH were exclusively associated with isolates of human origin. On the other hand, 3 saturated FAMEs, 10:0, 15:0, and 18:0 were found only in isolates from non-human sources, 15:0 being associated with livestock samples only. In addition to the presence of these signature FAMEs, the mean relative masses of 16:1 omega7c and 16:1 ISO/14:03 OH were significantly different between the isolates of human and non-human origins. A linear discriminant function differentiated FC isolates of human origin from those of livestock and wildlife origin at 99% accuracy. These results strongly suggest that the FAME profiles of FC show statistically significant host specificity and may have the potential to be used as a phenotypic microbial source tracking tool.     

Comparison of the efficacy of an existing versus a locally developed metabolic fingerprint database to identify non-point sources of faecal contamination in a coastal lake

A comparison of the efficacy of an existing large metabolic fingerprint database of enterococci and Escherichia coli with a locally developed database was undertaken to identify the sources of faecal contamination in a coastal lake, in southeast Qld., Australia. The local database comprised of 776 enterococci and 780 E. coli isolates from six host groups. In all, 189 enterococci and 245 E. coli biochemical phenotypes (BPTs) were found, of which 118 and 137 BPTs were unique (UQ) to host groups. The existing database comprised of 295 enterococci UQ-BPTs and 273 E. coli UQ-BPTs from 10 host groups. The representativeness and the stability of the existing database were assessed by comparing with isolates that were external to the database. In all, 197 enterococci BPTs and 179 E. coli BPTs were found in water samples. The existing database was able to identify 62.4% of enterococci BPTs and 64.8% of E. coli BPTs as human and animal sources. The results indicated that a representative database developed from a catchment can be used to predict the sources of faecal contamination in another catchment with similar landuse features within the same geographical area. However, the representativeness and the stability of the database should be evaluated prior to its application in such investigation.     

武汉工业学院新校区图书馆设计

通过对武汉工业学院新校区图书馆的方案设计,对现代图书馆的建筑设计特点进行了研究,指出其平面采用集约化布局方式,将编、藏、借、阅各区独立设置,分区明确,以建造出内部空间布局合理、视觉效果独特、文化内涵丰富的现代图书馆。     

浅析中国古典园林中的视觉造型艺术

对中国古典园林进行了简要概述,并且从视觉造型的角度对中国古典园林的四大造景要素以及空间组织进行分析,希望从视知觉的角度来寻求中国古典园林在现代景观设计中的发展方向。     

琴台文化艺术中心及文化广场规划方案评析

通过琴台文化艺术中心的设计实践，从城市尺度入手，构筑涉及人与环境之间视觉和心理、行为感觉上的联系。并针对这个项目，将琴台文化艺术中心总体规划布局的设计创意进行介绍和评析。     

基于时空马尔可夫随机场模型的车辆跟踪算法研究

鲁棒的车辆跟踪是实现交通事件自动检测的重要前提,车辆跟踪中的车辆相互遮挡则是影响车辆跟踪结果的关键因素。针对这一难题,设计自适应的车辆跟踪算法,并依据交通图像序列的时空相关性,根据马尔可夫的基本理论和贝叶斯方法,应用MRF-MAP理论分析框架,并结合了彩色图像序列的纹理信息建立了图像序列的时空马尔可夫随机场模型。采用随机松弛算法中的Metropolis算法来求解时空马尔可夫随机场模型,对车辆跟踪得到的目标标号图进行优化,从而解决车辆跟踪中的遮挡问题。初步实验结果,跟踪不遮挡的车辆时达到的跟踪成功率为95%。遮挡情况时成功率也可达到83%。实验结果表明,该跟踪算法在不遮挡时效果非常理想,在遮挡情况下跟踪鲁棒性也较好。     

车辙的成因及控制指标

介绍了车辙的种类，分析了发生车辙的原因，阐述了车辙控制指标的计算以及车辙深度的控制标准，从而为公路建设者提供理论指导。     

Quo vadis source tracking? Towards a strategic framework for environmental monitoring of fecal pollution

Advances in microbial source tracking (MST) have largely been driven by the need to comply with water quality standards based on traditional indicator bacteria. Recently, a number of culture-independent, and library-independent methods based on polymerase chain reaction (PCR) have been gaining popularity among source trackers. However, only a limited number of these methods have been successfully used in field applications, primarily due to the fact that many of them are still being developed. In this critical outlook, we examine different viewpoints associated with the practical use of MST to identify critical research gaps, propose a priority-based timeline to address them, and outline emerging technologies that will likely impact the future of source tracking. We propose that it is necessary to consider each of these aspects in order to advance towards a unifying framework in source identification, so that fecal pollution monitoring can be reliably used for comprehensive environmental microbial monitoring, to develop risk assessment models, and to implement and validate adequate management practices.     

走向景观感应——景观感知及视觉评价的传承发展

基于笔者40年来的研究与实践,回顾了景观感知及视觉评价在风景园林学科专业中的重要影响及其60年来引领风景园林美学走向科学理性的积极作用。以生命体的视角,提出应从时空、能量、信息三维度重新审视风景园林,进而依据人类2 000年来走过的风景园林景观-感知“五阶段”,重新认识、定义景观感知及视觉评价的关键作用;重温景观感知领域研究的缘起、初心及早期的科学研究观与创新成就,借以分析目前该领域研究的关键问题成因:重复性的应用研究有余而开创性的理论探索不足,分析、分解思维方法有余而综合、整合体系的思维方法缺失。论证了以“交叉、综合、体系”理念发展景观感知理论的必要性,提出了景观感应理论的基本思想,阐述了涵盖全景观感应五方面的5个“元素体”及其组成的“三元耦合”ד二元互动”ד主客合一”的哲学主张,由此构建起了一个全面、综合、一体的景观感应体系化框架,旨在推进景观感知及视觉评价研究与应用走向体系化,让景观感应在风景园林学科及其美学领域中发挥更大的引领理论研究与指导规划设计实践的作用。     

Relationships between Bacteroides 16S rRNA genetic markers and presence of bacterial enteric pathogens and conventional fecal indicators

Occurrence and prevalence of different bacterial enteric pathogens as well as their relationships with conventional (total and fecal coliforms) and alternative fecal indicators (host-specific Bacteroides 16S rRNA genetic markers) were investigated for various water samples taken from different sites with different degrees of fecal contamination. The results showed that a wide range of bacterial pathogens could be detected in both municipal wastewater treatment plant samples and in surface water samples. Logistic regression analysis revealed that total and human-specific Bacteroides 16S rRNA genetic markers showed significant predictive values for the presence of Escheriachia coli O-157, Salmonella, heat-labile enterotoxin (LT) of enterotoxigenic E. coli (ETEC), and heat-stable enterotoxin for human (STh) of ETEC. The probability of occurrence of these pathogenic bacteria became significantly high when the concentrations of human-specific and total Bacteroides 16S rRNA genetic markers exceeded 10(3) and 10(4) copies/100 mL. In contrast, Clostridium perfringens was detected at high frequency regardless of sampling sites and levels of Bacteroides 16S rRNA genetic markers. No genes related to Shigella spp., Staphylococcus aureus and Vibrio cholerae were detected in any samples analyzed in this study. Conventional indicator microorganisms had low levels of correlation with the presence of pathogens as compared with the alternative fecal indicators. These results suggested that real-time PCR-based measurement of alternative Bacteroides 16S rRNA genetic markers was a rapid and sensitive tool to identify host-specific fecal pollution and probably associated bacterial pathogens. However, since one fecal indicator might not represent the relative abundance of all pathogenic bacteria, viruses and protozoa, combined application of alternative indicators with conventional ones could provide more comprehensive pictures of fecal contamination, its source and association with pathogenic microorganisms.