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101.
Saurabh Baruah Goutam Kashyap Boruah Sangeeta Sharma Washim Akram Hoque Timangshu Chetia Chandan Dey 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2020,14(2):112-127
ABSTRACTThe concept of seismic vulnerability is a yard-stick of damage estimation from a probable earthquake considering physical cum social dimension and enables a basis for decision-makers to develop preparedness and mitigation strategies. We aim at vulnerability assessment of the typical urban system of capital city Shillong situated on hilly terrain. High-resolution satellite imagery of Shillong facilitates analysis of building footprints, communication network, and open ground. Different building typologies are identified taking into account the building’s structural configuration assessed through a rapid visual survey of more than 15% of total residential households. Slope map demarcates the landslide-prone area through discrete elevation modelling. A methodology incorporating several parameters e.g. building typology, slope angle, shear wave velocity characteristics, geomorphology, and the number of occupants in correlation with a physical measurement of vulnerability is presented and is applied to estimate the dimension of vulnerability. Additionally, MASW survey indicates lithology up to 30?m deep along with the existence of stiff soil and rocks at different depths whereas resonant frequency is identified to be in the range of 6–8?Hz through H/V ratio. Integrating all, it is observed that more than 60% of Shillong city falls under moderate to higher vulnerability and the rest is less vulnerable. 相似文献
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104.
Xuanwen LU Xueqin TAO Zhi DANG 《中国地球化学学报》2006,25(B08):115-116
Chloramphenicol (CAP) is an antibiotic commonly used in aquaculture as a prophylactic or disinfectant to prevent diseases, or as a chemotherapeutic agent to control diseases. This antibiotic is either spread directly in the aquatic environment or administered through medicated feeds. It may be directly exposed to or enter the environment by leaching from uneaten feeds or from the aquatic animals' excrements. The antibiotic also directly enters the environment through pharmaceutical wastewater. Toxicity of CAP to human bone marrow has been linked to fatal aplastic anemia. Antimicrobial residues enter the environment, which may also establish a selective pressure in favour of antimicrobial-resistant bacteria. The residues of antibiotics may pose potential risk to public health or increase the occurrence of antibiotic-resistant bacteria in the aquatic environment. Due to these perceived risk, treatment of CAP in farm animals intended for human consumption has been restricted. However, residue of CAP in the environment is still a concern. There have been some reports on the residual effects of CAP on aquaculture and on microbial resistance to CAP in certain environments. The biotransformation of CAP in aquaculture pond sediments has been reported, which indicated that salinity is one of the many environmental factors that affect the degradation of CAP. However, acclimatization and screening of dominant bacteria for biodegrading CAP have been rarely studied. This paper studied the microbial degradation of CAP. In order to screen the dominant bacteria for degrading, the source of bacteria was sampled from the aquaculture pond sediments of Baiyun Borough, Guangzhou, China. 60 mg/L CAP was used as a sole carbon source to screen CAP-degrading bacteria and the dominant bacteria were acclimated after 2 months. 相似文献
105.
The concentrations of particulate Polycyclic aromatic hydrocarbons (PAHs) were measured at Gosan, a background site in Korea for 1 year between November 2001 and November 2002. The total concentrations of 14 PAH compounds at Gosan were between 0.52 and 14.76 ng m− 3 and about 3–15 times higher than those at other rural or remote sites in the world. Seasonal trend was observed for particulate PAHs concentrations at Gosan with higher levels during heating season due to increased fossil fuel usage and the movement of air parcels from Asian continent. Principal component factor analysis (PCF) for PAHs showed three factors; combination of coal combustion and vehicular emission, natural gas combustion, and unidentified one. However, PCF for the combined data of PAHs, inorganic ions, and elements revealed that the unidentified factor consists of crustal species, sea salts, and four PAH compounds. Thus, this factor is thought to be transport of crustal species with organics from combustion sources. The major variables which determine the sources of PAHs are the heating season and the movement of air parcels from Asian continent. 相似文献
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Geochemical factors controlling the chemical nature of water and sediments in the Gomti River, India 总被引:3,自引:2,他引:1
R-mode factor analysis of the recently acquired data on water and sediment chemistry has been performed. Basic chemical parameters
have been merged together which aid in interpreting a few empirical geochemical factors controlling the chemical nature of
water and sediments of the Gomti River, a major Himalayan tributary of the Ganges drainage basin. Water chemistry seems to
be controlled by three factors: bicarbonate, rainfall and silicate and phosphate factors. Sediment chemistry is largely controlled
by the following four factors: clay, adsorption/desorption, Fe-Mn hydroxide and mercury factors. These factors show spatial
and temporal variability in terms of their R-scores.
Received: 8 September 1997 · Accepted: 15 December 1997 相似文献
108.
测定了8个不同耐盐性的甘蔗品种在正常和盐胁迫下的一些形态、生理指标的损伤率,并用因子分析进行了分析。分析表明,甘蔗苗期的耐盐性指标可以划分为反映甘蔗受盐害时物质形态伤害程度的植株形态指标和反映植株受害时生理和物质代谢活动变化的生理指标两大类型,其中植株形态指标是评价甘蔗苗期耐盐性的主要指标。并用这两类综合指标对参试品种苗期耐盐性大小进行了排序。 相似文献
109.
结合水氧、应力观测资料对甘肃武山地区地下流体化学特征(水化学、气体化学)与构造应力关系进行了定量计算并给出了二者之间的数学关系。 相似文献
110.
吴晓清 《武汉大学学报(信息科学版)》1989,(4)
文中阐述了权因子法方差分量估计的原理。利用权因子的概念,对目前方差分量估计存在的几个问题,如负方差问题,作了探讨,并与Helmert法进行比较,得出了一些有益的看法。 算例很好地说明了权因子法方差分量估计的简便和实用性。 相似文献