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91.
Objectives This paper aims to provide evidence of an inductive electromagnetic bioeffect on the human brain, which is independent from sound waves and produced by mobile phones, in proximal field, through correlating the EEG data obtained from electrodes placed on both normal and cochlear deaf individuals. Methods Two groups of subjects are placed under controlled electromagnetic conditions inside a Faraday chamber, 12 healthy and another 12 suffering from cochlear deafness). Each is sitting on a chair, fitted with additional support, and holding a cellular phone 2 cm away form the right auricular, in order to avoid a thermal effect as much as possible. All of them, relaxed and with their eyes closed, are EEG recorded in a basal state with their mobile phones off. Then, each of them is again recorded under the same conditions but with the mobile on and listening to the same conversation. In order to assess the observed EEG changes, a statistical analysis by means of the FFT (Fast Fourier Transform) was carried out. Results For both, healthy and cochlear deaf, assimilation or integration of the mobile phone signal by some electrodes is to be found. This is due to the increase of amplitudes for alpha and theta waves, whereas the signal is not integrated in other electrodes. By correlating the spectra of frequencies of corresponding EEG records for the same brain areas, we have not observed significative differences for both groups. Conclusions A possible electromagnetic direct inductive, non-thermal, bioeffect on the human brain is observed. This effect is produced by the use of mobile phones and it bears no relation to the sound waves.  相似文献   
92.
在线衍生化吹扫捕集-气相色谱/质谱分析水中的五氯酚   总被引:1,自引:0,他引:1  
建立了通过乙酸酐衍生化-吹扫捕集-气相色谱/质谱分析水中五氯酚的新方法,探讨了吹扫时间、样品池温度、离子强度以及衍生化试剂的加入量等条件对捕集效果的影响。结果表明:采用吹扫时间25min、样品池温度60℃、离子强度20%氯化钠以及衍生化试剂的量200μl等条件对水中的五氯酚有较好的捕集效果,用于水中五氯酚的测定,结果满意。  相似文献   
93.
本研究建立了一种用空气-乙炔火焰原子吸收分光光度法测定浸渍活性炭中银含量的分析方法,对酸介质浓度、共存元素的干扰进行了探讨,在0—1.0ml沪范围内,银含量与吸光度呈线性关系,相关系数为0.9999。对09型浸渍活性炭标准物质进行测定,测定结果的相对标准偏差为0.191%(n=10),加标回收率为97.5%-101.4%。  相似文献   
94.
ABSTRACT: Several methods for synthetic unit hydrographs are available in the literature. Most of these methods involve the hand fitting of a curve over a set of a few hydrograph points, which can sometimes be a subjective task. Besides, the user often finds it difficult or simply neglects to adjust the generated unit graph to a runoff volume of one unit (inch, cm, or mm). It is the purpose of this paper to present to the design hydrologist a simple method to fit a smooth gamma distribution over a single point specified by the unit hydrograph peak and the time to peak with a guaranteed unit depth of runoff.  相似文献   
95.
This study attempted to investigate whether increased hair lead concentrations due to environmental exposure are accompanied by parallel increases in blood lead concentrations. A sample set consisting of both occupationally-exposed individuals and persons from the general population was investigated. The lead content of scalp and pubic hair from the general population (n=189), traffic police personnel (n=27) and battery workers (n=22) were analysed. The hair samples were taken from the nape of the neck by cutting 23 cm closest to the scalp and cleaned using a washing procedure developed in our laboratory. The effectiveness of the washing procedure was partly determined by examining the scanning electron micrographs of the hair samples. Venous samples of blood were taken from each volunteer's arm.The traffic police and battery plant operators sampled had significantly higher average scalp hair and pubic hair lead levels than the non occupationally-exposed general population. No significant differences were found between the blood lead values of these workers and the general population. Compared to the general population both occupationally-exposed groups had significantly more symptoms of lead toxicity.Lead particles were still observed on the hair shafts after the washing procedure. The amount of such lead contamination was difficult to quantify, the problem being further exacerbated by the difference in hair texture of the persons sampled. This exogenous contamination therefore detracts from the usefulness of hair as an indicator of lead exposure.  相似文献   
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98.
Estuarine ecosystems are largely influenced by watersheds directly connected to them. In the Mobile Bay, Alabama watersheds we examined the effect of land cover and land use (LCLU) changes on discharge rate, water properties, and submerged aquatic vegetation, including freshwater macrophytes and seagrasses, throughout the estuary. LCLU scenarios from 1948, 1992, 2001, and 2030 were used to influence watershed and hydrodynamic models and evaluate the impact of LCLU change on shallow aquatic ecosystems. Overall, our modeling results found that LCLU changes increased freshwater flows into Mobile Bay altering temperature, salinity, and total suspended sediments (TSS). Increased urban land uses coupled with decreased agricultural/pasture lands reduced TSS in the water column. However, increased urbanization or agricultural/pasture land coupled with decreased forest land resulted in higher TSS concentrations. Higher sediment loads were usually strongly correlated with higher TSS levels, except in areas where a large extent of wetlands retained sediment discharged during rainfall events. The modeling results indicated improved water clarity in the shallow aquatic regions of Mississippi Sound and degraded water clarity in the Wolf Bay estuary. This integrated modeling approach will provide new knowledge and tools for coastal resource managers to manage shallow aquatic habitats that provide critical ecosystem services.  相似文献   
99.
An improved method for trace level quantification of dicyandiamide in stream water has been developed. This method includes sample pretreatment using solid phase extraction. The extraction procedure (including loading, washing, and eluting) used a flow rate of 1.0 mL/min, and dicyandiamide was eluted with 20 mL of a methanol/acetonitrile mixture (V/V = 2:3), followed by pre-concentration using nitrogen evaporation and analysis with high performance liquid chromatography–ultraviolet spectroscopy (HPLC–UV). Sample extraction was carried out using a Waters Sep-Pak AC-2 Cartridge (with activated carbon). Separation was achieved on a ZIC®-Hydrophilic Interaction Liquid Chromatography (ZIC-HILIC) (50 mm × 2.1 mm, 3.5 μm) chromatography column and quantification was accomplished based on UV absorbance. A reliable linear relationship was obtained for the calibration curve using standard solutions (R2 > 0.999). Recoveries for dicyandiamide ranged from 84.6% to 96.8%, and the relative standard deviations (RSDs, n = 3) were below 6.1% with a detection limit of 5.0 ng/mL for stream water samples.  相似文献   
100.
主要阐述了气相分子吸收光谱法测定氨氮的校准曲线斜率、截距参考值的分析.文章收集了临安市环境监测站实验室自2012年以来气相分子吸收光谱法氨氮校准曲线制作的一系列原始数据,并通过数理统计方法对校准曲线、残余标准偏差、斜率扩展不确定度、截距扩展不确定度开展了详细讨论,得出气相分子吸收光谱法氨氮校准曲线截距a值、斜率b值实验室参考值.此结果对实验室分析人员判定氨氮项目校准曲线制作是否合格具有一定的参考价值.  相似文献   
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