Simultaneous effect of shift work on blood pressure and lipid profile: a path analysis

The aim of this study was to assess the direct and indirect effects of shift work (SW) on the systolic blood pressure (SBP) and lipid profile of male workers. For this purpose, a cross-sectional study was conducted involving 6539 male workers of Esfahan Mobarakeh Steel Company. From all of the participants, 3065 (46.8%) were day workers and the remainder were shift workers. The results of path analysis revealed that the most effective variables on SBP were body mass index, fasting blood sugar, triglycerides and SW with a total effect of 0.241, 0.095, 0.064 and 0.056, respectively.     

Experimental study on microalgae cultivation in novel photobioreactor of concentric double tubes with aeration pores along tube length direction

Microalgae have been identified as a superior feedstock for biodiesel production and varied tubular photobioreactors are developed for high efficient and scale-up microalgae cultivation. This article presented a novel concentric double tubes using aeration through radial pores along the length direction of inner tube. Experiments on microalgae cultivation were carried out in the novel photobioreactor, and two control groups including concentric double tubes with axial aeration at both ends and common tubular. The biomass productivity of novel photobioreactor increased by 43.6% and 107.4%, respectively, compared with concentric double tubes with axial aeration at both ends and common tubular without aeration. The values of pH shifted from 7.5 to 9.0 for novel photobioreactor, but 7.5 to 8.8 for common tubular, and 7.5 to 9.6 for concentric double tubes with axial aeration. The dissolved oxygen concentration fluctuated between 6.0 and 7.0 mg·L^?1 for novel photobioreactor, but rose from 6.6 to 10.2 mg·L^?1 for the common tubular, and 6.9 to 8.1 mg·L^?1 for the concentric with axial aeration. Results show that the aeration style of novel photobioreactor can make efficient local mixing and maintain smaller range of pH and lower level of dissolved oxygen in case of higher biomass concentration. Moreover, compared with the two control groups, the novel concentric double tubes have advantages on the light/dark cycle frequency, which may be benefit for microalgae cultivation. The novel concentric double tubes presented in this work can give some inspiration for high efficiency microalgae cultivation.     

Grassland Plant Composition Alters Vehicular Disturbance Effects in Kansas,USA

Many “natural” areas are exposed to military or recreational off-road vehicles. The interactive effects of different types of vehicular disturbance on vegetation have rarely been examined, and it has been proposed that some vegetation types are less susceptible to vehicular disturbance than others. At Fort Riley, Kansas, we experimentally tested how different plant community types changed after disturbance from an M1A1 Abrams tank driven at different speeds and turning angles during different seasons. The greatest vegetation change was observed because of driving in the spring in wet soils and the interaction of turning while driving fast (vegetation change was measured with Bray-Curtis dissimilarity). We found that less vegetation change occurred in communities with high amounts of native prairie vegetation than in communities with high amounts of introduced C₃ grasses, which is the first experimental evidence we are aware of that suggests plant communities dominated by introduced C₃ grasses changed more because of vehicular disturbance than communities dominated by native prairie grasses. We also found that vegetation changed linearly with vehicular disturbance intensity, suggesting that at least initially there was no catastrophic shift in vegetation beyond a certain disturbance intensity threshold. Overall, the intensity of vehicular disturbance appeared to play the greatest role in vegetation change, but the plant community type also played a strong role and this should be considered in land use planning. The reasons for greater vegetation change in introduced C₃ grass dominated areas deserve further study.     

应用细胞合成计量关系模型分析鱼腥藻7120的混合营养生长

根据文献中鱼腥藻细胞大分子的含量和组成情况,计算了细胞合成所需要的小分子单体和前体代谢物的量,得到代谢意义上的细胞生物合成计量关系,此计量关系模型,对鱼腥藻7120细胞在气升式光生物反应器中光自养和混合营养生长的对数生长阶段进行了代谢通量分析。结果表明,葡萄糖的利用影响细胞初级碳代谢的流动状况,混合营养生长过程比光自养生长过程磷酸戊糖途径氧化性分支的反应程度明显加强,随着培养的进行,葡萄糖被细胞用作碳源的比例可能减小,而用作能源的比例可能增大。     

基于MFA的青岛市城阳区物质代谢研究

基于欧盟的物质流分析(MFA)框架,对青岛市城阳区的物质代谢状态和代谢强度进行了系统分析.结果表明:1995─2004年城阳区资源投入量和污染物排放量分别增长3.6和1.8倍,化石燃料和矿物约占资源投入量的50.26%～76.30%,进口资源量所占比例呈逐年增长趋势,经济发展的资源外部依赖性较强.万元GDP资源投入由6.01 t降至3.56 t,万元GDP污染物排放量也降低了63.74%,表明城阳区经济发展的资源利用效率和生态效率已有不同程度的提高,但仍远高于发达国家20世纪末期的水平,因此提高资源生产力和控制污染物排放是实现城阳区可持续发展的必由之路.      

跨世纪江苏沿江地区产业结构研究

江苏沿江地区包括南京、无锡、苏州、常州、镇江、南通、扬州、泰州八市,社会经济发达,人口和城镇密集,是长江三角洲地区的重要组成部分、江苏省经济发展最重要的地区之一。通过对该地区产业结构现状、区位优势条件物社会经济基础的分析,拽出在经济全球化和我国开放格局下本地区产业结构重组与升级所面临的机遇,及地区矿产资源缺乏、自然条件相似、产业结构趋同等不足。提出该地区跨世纪区域产业结构的发展战略是在维持第一产业     

环境补偿费的征收与转嫁

运用经济学基本原理分析了征收环境补偿费的理论依据,论述了在征收过程中可能对物价带来的影响以及环境补偿的转嫁问题。征收环境补偿是解决环境问题,实现可持续发展的重要手段。     

A simulation model for projecting changes in salinity concentrations and species dominance in the coastal margin habitats of the Everglades

Sharp boundaries typically separate the salinity tolerant mangroves from the salinity intolerant hardwood hammock species, which occupy the similar geographical areas of southern Florida. Evidence of strong feedback between tree community-type and the salinity of the unsaturated (vadose) zone of the soil suggests that a severe disturbance that significantly tilts the salinity in the vadose zone might cause a shift from one vegetation type to the other. In this study, a model based upon the feedback dynamics between vegetation and salinity of the vadose zone of the soil was used to take account of storm surge events to investigate the mechanisms that by which this large-scale disturbance could affect the spatial pattern of hardwood hammocks and mangroves. Model simulation results indicated that a heavy storm surge that completely saturated the vadose zone at 30 ppt for 1 day could lead to a regime shift in which there is domination by mangroves of areas previously dominated by hardwood hammocks. Lighter storm surges that saturated the vadose zone at less than 7 ppt did not cause vegetation shifts. Investigations of model sensitivity analysis indicated that the thickness of the vadose zone, coupled with precipitation, influenced the residence time of high salinity in the vadose zone and therefore determined the rate of mangrove domination. The model was developed for a southern Florida coastal ecosystem, but its applicability may be much broader.     

长年耕作对北方旱作麦田土壤细菌群落结构及理化性质的影响

为探究旱作麦田长期耕作对不同土层细菌群落结构的影响及其与土壤理化性质的关系,于2016~2021年在山西农业大学闻喜旱地小麦试验示范基地开展长期定位试验,研究夏闲期免耕（NT）、深松（ST）和深翻（DP）这3种耕作方式对不同土层土壤理化性质,细菌群落α、β多样性,细菌门和属优势物种及差异物种的影响,并采用PICRUSt2预测其代谢功能.结果表明,旱作麦田连续5a深松和深翻较免耕显著提高了20~40 cm土层土壤含水量,显著降低了0~20 cm土层土壤有机碳含量;深松较深翻显著提高了0~20 cm土层土壤含水量、土壤有机碳、可溶性有机碳和可溶性有机氮含量.深松和深翻较免耕可提高0~40 cm土层土壤细菌群落的α多样性,且深松高于深翻.深松和深翻较免耕显著提高了0~20 cm土层中酸杆菌门、硝化螺旋菌门和20~40 cm土层中酸杆菌门、绿弯菌门、芽单胞菌门、Rokubacteria门、GAL15门和硝化螺旋菌门的相对丰度;显著提高了0~20 cm土层硝化螺旋菌属和20~40 cm土层Rubrobacter属和链霉菌属的相对丰度.深松较深翻显著提高了0~40 cm土层酸杆菌门、芽单胞菌门的相对丰度.冗余分析表明,0~20 cm土层的土壤有机碳、可溶性有机碳和可溶性有机氮含量对放线菌门和牙殖球菌属产生正向效应,且深松下0~40 cm土层的土壤含水量对酸杆菌门、绿弯菌门和芽单胞菌门产生正向效应.PICRUSt2预测结果表明,深松和深翻较免耕显著提高了20~40 cm土层细菌群落的氨基酸代谢和辅酶维生素代谢的相对丰度,但降低了脂质代谢的相对丰度;深松较深翻显著提高了0~40 cm土层细菌群落的氨基酸代谢和0~20 cm土层其他氨基酸代谢的相对丰度.总之,旱地麦田夏闲期深松或深翻均可提高土壤含水量、土壤细菌群落的α多样性及细菌群落的代谢能力,深松还可提高酸杆菌门和芽单胞菌门的相对丰度,并提高细菌群落的氨基酸代谢能力,从而提高了土壤可溶性有机碳、氮含量.     

渭河流域水体细菌群落的环境响应及生态功能预测

流域水体中细菌群落多样性及其代谢功能研究对流域水污染整治及生态修复和水体健康评价具有重要价值.基于Illumina MiSeq高通量测序技术研究渭河流域陕西境内综合治理后水体中细菌群落分布特性,利用冗余分析(redundancy analysis,RDA)方法分析了水体细菌群落与水环境因子的相关关系,并采用PICRUSt (phylogenetic investigation of communities by reconstruction of unobserved states)方法预测和评价了渭河流域细菌群落生态功能.研究结果显示,变形菌门、放线细菌门、蓝藻门和拟杆菌门细菌是水体细菌群落中的主要菌门,占整个细菌群落的相对丰度高达85%,这类细菌与水体中的TP、NO_2~--N、NO_3~--N和TN呈显著的正相关关系(P=0. 02 0. 05);灞河入渭口下游(S5)细菌群落丰度最高,皂河(S4)细菌群落丰度最低;渭河流域水体致使人类患传染性疾病的可能性较大,且对生物体内分泌系统有较大的影响.本研究成果可为渭河流域水环境健康有序发展提供理论基础.