Antimicrobial Resistance Genes in Pigeons from Public Parks in Costa Rica

Antimicrobial resistance is known to be an emerging problem, but the extent of the issue remains incomplete. The aim of this study was to determine the presence or absence of nine resistance genes (bla_TEM, catI, mecA, qnrS, sulI, sulII, tet(A), tet(Q), vanA) in the faeces of 141 pigeons from four urban parks in Alajuela, Guadalupe, Tres Ríos and San José in Costa Rica. The genes were identified by real‐time PCR directly from enema samples. About 30% of the samples were positive for genes catI and sulI; between 13% and 17% were positive for qnrS, sulII, tet(A) and tet(Q); and 4% were positive for bla_TEM. The mecA and vanA genes were not detected. The average of antimicrobial resistance genes detected per pigeon was 2. Eight different patterns of resistance were identified, without differences in the sampling areas, being the most common pattern 2 (sulII positive samples). During rainy season, the genes more frequently found were sulI and tet(A). In conclusion, the urban inhabiting pigeons tested are currently carrying antimicrobial resistance genes, potentially acting as reservoirs of resistant bacteria and vectors to humans. To the authors’ knowledge, this is the first study carried out on direct detection of resistance genes in the digestive metagenomes of pigeons.     

人文精神变革下的城市视觉污染及其防治

城市的发展建设是建设文明社会、和谐社会的重要组成部分。在人文精神的引导下，城市建设应朝着人与自然的和谐方向发展。然而现代城市中出现的各种视觉上的污染及其所造成的危害，却与我们所提倡发展城市人文精神，建立人文城市的内涵相违背。本文在分析了城市的硬环境和软环境存在的几个重要的视觉污染的基础上，提出了发展人文城市，杜绝城市污染源的几点建议。     

西安市44个草坪草品种引种试验研究

为选择适合西安市城市绿化草坪草种,于2001—2003年在西安市进行了草坪草引种试验研究,其中包括黑麦草、羊茅、翦股颖、早熟禾属在内的44个品种。通过建立草坪草评价体系,观察了草坪草颜色、盖度、密度、均一性等4项指标,并筛选出适应性较好,品质相对优良的早熟禾,高羊茅等草坪草品种,以供西安市绿化建植草坪参考。     

16S rRNA甲基化酶rmtB在猪肠道菌中的传播方式分析

为研究16S rRNA甲基化酶rmtB在猪肠道菌中的传播方式,用脉冲场凝胶电泳(PFGE)分别对来源于A、B猪场的48株rmtB阳性大肠埃希氏菌进行基因分型;用膜接合试验研究rmtB基因的水平传播方式;用微量稀释法对rmtB阳性菌及其接合子进行药敏试验。有45株rmtB阳性大肠埃希氏菌(45/48)能进行PFGE分型,可分为28种不同的PFGE基因型。其中来源于A猪场的20株菌可分为12种基因型,来源于B猪场的25株菌可分为16种基因型;46株rmtB阳性菌可以通过接合试验将rmtB基因及其介导的耐药性传递给受体菌E.coliC600和E.coli488 Rifr,接合频率从4.6×10-13~3.0×10-6不等,接合子对卡那霉素、阿米卡星、妥布霉素、西梭米星、萘替米星、庆大霉素6种二脱氧链霉胺类抗生素均高度耐药(MIC≥512μg/mL)。结果表明,rmtB基因位于接合性质粒上,该基因在两猪场的大肠埃希氏菌中既存在克隆传播,又存在水平传播,以水平传播为主。     

“绿量”在城市绿化中的应用研究

通过概述绿量概念的发展过程,介绍了绿量指标从二维平面到三维空间的进步,阐述了绿量概念和提出的意义,介绍了城市三维绿量的测算方法,指出了现在研究中存在的问题。希望通过对绿量概念的进一步阐述,将人们的思维引入到如何充分利用有限绿化空间、科学配置植物及对植物的生态效益进行量化的层面,进而营造较好的绿化模式,提高城市绿地的整体生态效益。     

Identification of sorghum genotypes suitable for specific end uses: Semolina recovery and popping

There has always been an interest in devising breeding programs for designer foods that would benefit both the producer and consumer. The challenge today is transformation of agriculture from “subsistence farming” to “market and income generation oriented” production system for which sorghum with its diverse end uses can assume significant role. Breeding for end-use identity-specific genotypes is needed for increased profitability to the farmers. In the present study, 60 sorghum genotypes were evaluated over two years to identify genotypes suitable for semolina recovery and popping properties, i.e. popping efficiency and pop volume expansion. Semolina recovery ranged from 20.7% to 48.3%, while popping efficiency ranged from 0 to 77.5%. Semolina recovery had positive and significant association with endosperm texture (r = 0.62), grain density (r = 0.49) and grain hardness (r = 0.55) indicating that genotypes with corneous endosperm yield high semolina. Also, semolina recovery had significant positive correlation with popping efficiency (r = 0.49) indicating that genotypes suitable for semolina can also be used for popping. Genetic divergence studies indicated that out of three clusters formed, cluster II having guinea race germplasm lines are suitable for semolina and popping. The information generated and the genotypes identified will help in enhancing the demand for sorghum as an industrial crop.     

大型渡槽槽身施工技术进展

阐述我国大型渡槽槽身施工技术的若干最新进展，并探讨了大型梁式渡槽槽身施工中的支撑浇筑系统、伸缩缝止水、预应力张拉等问题，提出大型渡槽槽身施工中支撑系统、施工方法、预应力张拉次序的选择，可供实际工程施工借鉴。     

统筹城乡户籍制度改革与农村人口空心化：挑战与应对

从统筹城乡户籍制度改革对农村资源配置、农村有效投入、农村规模发展及农村技术人才4个方面分析统筹城乡户籍制度改革可能给农村发展造成人口空心化带来的影响和挑战,最后,基于土地流转、农村新型养老保险和发展农业机械化等角度提出了相应的建议。     

杭州城乡空间生态规划初步研究

21世纪城市发展趋势是走可持续发展的道路,城市规划引入了生态规划的原理和方法。在经济理性、社会理性等各种规划理论的基础上,强调了物质空间建设和自然生态协同发展的空间规划,形成一种人与自然和谐相处的环境。以杭州市的生态规划为例进行探讨,从生态规划的角度出发,提出农业生态、工业生态和文化生态建设,进行城乡规划的反思与初步探讨。     

乌拉特前旗耕地变化的驱动力研究及预测

阐述了城市河道生态护坡综合评价的基本内容,指出当前评价中指标体系建立的不足。认为评价指标体系的建立应科学合理地反映出所要评价的生态护坡系统的各项指标要求。建立了合肥市城市河道生态护坡评价指标体系,该体系的内容包括城市河道生态护坡类型及材料、稳定性、功能和社会经济效益4项指标要求,并采用层次分析法进行了工程实例分析,评价结果良好地反映了四里河和南淝河生态护坡的特性。该指标体系的建立,为合肥市生态护坡的评价奠定了基础,对城市生态护坡建设具有一定指导意义。