公路工程区域报价的多样性及其统一性

通过对产生公路工程区域报价多样性的原因进行分析，提出了规范与统一报价的具体措施，并指出投标阶段关系到产品的质量与投资者实施项目的标底。     

Challenges for a shared European countryside of uncertain future. Towards a modern community-based landscape perspective

This paper addresses current changes in the highly diverse European landscape, and the way these transitions are being treated in policy and landscape management in the fragmented, heterogeneous and dynamic context of today’s Europe. It appears that intersecting driving forces are increasing the complexity of European landscapes and causing polarising developments in agricultural land use, biodiversity conservation and cultural landscape management. On the one hand, multifunctional rural landscapes, especially in peri-urban regions, provide services and functions that serve the citizens in their demand for identity, support their sense of belonging and offer opportunities for recreation and involvement in practical landscape management. On the other hand, industrial agricultural production on increasingly large farms produces food, feed, fibre and energy to serve expanding international markets with rural liveability and accessibility as a minor issue. The intermediate areas of traditionally dominant small and family farms in Europe seem to be gradually declining in profitability. The paper discusses the potential of a governance approach that can cope with the requirement of optimising land-sharing conditions and community-based landscape development, while adapting to global market conditions.     

Soluble microbial products formation in anaerobic chemostats in the presence of toxic compounds

Anaerobic chemostats fed on glucose (approximately 10 g chemical oxygen demand (COD)/L) were used to investigate the effects of toxicity on soluble microbial product (SMP) formation. Addition of the toxic compounds chloroform and chromium increased the net accumulation of SMP, despite reducing the percentage of SMP in the effluent due to the overwhelming production of volatile fatty acids (VFAs). In the reactor spiked with chloroform the normalized accumulation of SMP (SMP/So) increased from 2% to 8%, whereas in the reactor spiked with Cr (VI) the SMP/So ratio reached as high as 20% after the spike, and in both cases SMP net accumulation was proportional to the concentration of toxicant. After the chloroform and chromium spikes biomass seemed to produce more extra cellular polymeric substances (EPS) suggesting that this might have helped them to cope with the stress. Chromatography results indicate that some of the high MW compounds present in the SMP might have been due to EPS release into the bulk solution, and that other compounds, probably released as a result of cell lysis, were also present. Hydrolysis of EPS did not seem to contribute to SMP accumulation in the presence of toxic compounds, and DNA analysis suggested that cell lysis products was an important contribution to SMP accumulation, in the presence of chromium.     

城市中央商务区(CBD)空间形态浅析

CBD作为一个城市功能区 ,由于其特殊的职能特征 ,在城市中形成了独特的空间形态 ,这一区域的空间形态是影响整个城市整体风貌的重要因素 .从形式、功能、空间角度出发 ,来阐述CBD的空间形态特征     

Identification and phylogeny of the small eukaryote population of raw and drinking waters

Culture-dependent and -independent methods were used to investigate the small eukaryote composition of raw and finished waters in the Norwegian cities of Oslo, Tromsø, Fredrikstad and Oppegård. Probes with general applicability to the 18S rRNA genes of the small eukaryote consortium were used for PCR-denaturing gradient gel electrophoresis (DGGE), and in the generation of clone libraries using the TOPO™ cloning and sequencing system. The chosen probes invariably gave a single band in agarose gel electrophoresis, indicating amplification of an area of similar size. DGGE and cloning analyses resolved the bands into components representing many unique amplicons. Diversity and composition in the collection were studied by DNA-sequencing, and visual examination of DGGE patterns. The cloning approach enabled the putative identification of a total of approximately 100 unique small eukaryotes. The major fraction of these represented ciliated and flagellated protozoal species. This was in keeping with the findings from protozoal cultivation. DNA from a number of multicellular eukaryotes was also detected. Amoebal and fungal DNA was rarely found. The latter may indicate a low incidence or a bias in the analysis technique. The population of small eukaryotes appears typical for pristine waters and no primary pathogens were detected by culture-independent techniques. However, the potentially pathogenic protozoa Acanthamoeba castellanii was grown on one occasion from Oslo’s drinking water.DGGE allowed the identification of fewer amplicons (by excision and sequencing of bands) than by the cloning-transformation approach. The DGGE analysis revealed clear similarities between the compositions of the raw and treated waters, indicating that cells or DNA in the raw water pass through the treatment trains. Protozoal culture and heterotrophic plate count analysis consistently revealed viable cells in both raw and treated waters in Oslo. This indicates that a fraction of the clone library represents eukaryotic species surviving the treatment trains. The analyses here presented represent the first published study of the general small eukaryotic fraction of the Capital’s drinking water, and those of three other Norwegian cities. We suggest that DGGE profiles may have a value in judging physical treatment efficacy (removal of cells), but that direct cloning and sequencing studies is more amenable for characterization of uncultured microbes.     

Carbon dioxide emission and its regulation at land–water interface downstream of a point source at Ganga River (India)

The streams and rivers are considered hotspots of CO₂ exchange; and representative direct CO₂ emission measurements are essential for a correct regional estimate. We measured CO₂ emission flux at 15 sites at land–water interface downstream of a point source during low flow for three consecutive months for the year 2017. The general range of CO₂ efflux observed here was close to the results of regional studies, although values near the point source were disproportionately high (>350 mg/m²/h). CO₂ emission flux showed strong dependence on total organic carbon (TOC; R² = 0.96; P < 0.001), (R² = 0.88; P < 0.001), soluble reactive‐P (SRP; R² = 0.91; P < 0.001) and microbial activity measured in terms of fluorescein diacetate activity (FDAase; R² = 0.92; P < 0.001) and substrate induced respiration (SIR; R² = 0.96; P < 0.001). Because point source‐associated interfaces provide heterogeneous habitats, our study suggests the need for large scale monitoring of CO₂ emission at land–water interface of major rivers for more correctly presenting the regional scale CO₂ budget.     

Plant tolerance to diesel minimizes its impact on soil microbial characteristics during rhizoremediation of diesel-contaminated soils

Soil contamination due to petroleum-derived products is an important environmental problem. We assessed the impacts of diesel oil on plants (Trifolium repens and Lolium perenne) and soil microbial community characteristics within the context of the rhizoremediation of contaminated soils. For this purpose, a diesel fuel spill on a grassland soil was simulated under pot conditions at a dose of 12,000 mg diesel kg^− 1 DW soil. Thirty days after diesel addition, T. repens (white clover) and L. perenne (perennial ryegrass) were sown in the pots and grown under greenhouse conditions (temperature 25/18 °C day/night, relative humidity 60/80% day/night and a photosynthetic photon flux density of 400 μmol photon m^− 2 s^− 1) for 5 months. A parallel set of unplanted pots was also included. Concentrations of n-alkanes in soil were determined as an indicator of diesel degradation. Seedling germination, plant growth, maximal photochemical efficiency of photosystem II (F_v/F_m), pigment composition and lipophylic antioxidant content were determined to assess the impacts of diesel on the studied plants. Soil microbial community characteristics, such as enzyme and community-level physiological profiles, were also determined and used to calculate the soil quality index (SQI). The presence of plants had a stimulatory effect on soil microbial activity. L. perenne was far more tolerant to diesel contamination than T. repens. Diesel contamination affected soil microbial characteristics, although its impact was less pronounced in the rhizosphere of L. perenne. Rhizoremediation with T. repens and L. perenne resulted in a similar reduction of total n-alkanes concentration. However, values of the soil microbial parameters and the SQI showed that the more tolerant species (L. perenne) was able to better maintain its rhizosphere characteristics when growing in diesel-contaminated soil, suggesting a better soil health. We concluded that plant tolerance is of crucial importance for the recovery of soil health during rhizoremediation of contaminated soils.     

现制饮料中微生物污染及其防控措施研究

鲜榨果蔬汁、现磨咖啡、新式茶饮等现制饮料深受消费者的喜爱,然而由于原材料品质把控不严、加工过程操作不规范等,导致现制饮料存在微生物污染的风险。本文综述了我国现制饮料中微生物污染状况及行业监管现状,分析了现制饮料在加工过程中微生物污染的原因,找出关键控制点并提出干预措施,为促进我国现制饮料行业的健康发展提出了建议。     

Joint Estimation of 2-D DOA and Polarization by Using the Linear Array with Diverse Polarizations

Antenna arrays with diverse polarizations havesome inherent advantages over the conventional uni-formly polarized array,for instance,higher accuracyof direction-of-arrival(DOA)esti mation,capabilityof resolving or separating signals based ontheir polar-ization characteristics as well as DOAs[1-7].Thepresence of polarization diversity,complicates themeasurement model which introduces a relativelyhigher computational requirement[8,9].Moreover,many existing algorithms proposed in the literature…     

“多元共生”——青海乡土民居建筑文化多样性研究

青海地处西北游牧与农耕的交汇处,民族文化多元,是我国中原文化、藏传佛教文化、伊斯兰文化融合交流的典型地区。通过对青海乡村环境的调研及民居测绘,系统分析了青海多元民族民居建筑文化的多样性,总结出各民族聚落及住居空间形态特征。指出建筑文化多样性源于地区自然地理环境、生产生活方模式及民族宗教文化自然与人文环境综合作用的结果。