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排序方式: 共有94条查询结果,搜索用时 15 毫秒
81.
Assessing the impact of waterborne and dietborne cadmium toxicity on susceptibility risk for rainbow trout 总被引:1,自引:0,他引:1
The purpose of this study was to use a risk-based integrated-scale toxicological model to examine the impact of waterborne and dietborne cadmium (Cd) toxicity on rainbow trout (Oncorhynchus mykiss) susceptibility appraised with recent published data. A probabilistic assessment model was performed to estimate Cd susceptibility risk. The dose-response models were constructed based on two endpoints of % Cd in metabolically active pool (MAP) and susceptibility time that causes 50% effect (ST50). We further constructed an elimination-detoxification-recovery scheme to enhance the model predictive ability. We found a 95% probability of % Cd in gill and liver MAP exceeding 47-49% and it was likely (70% probability) to have exceeded 52-55%, but it was unlikely (30% probability) to have exceeded 56-60%. In contrast to gill and liver, gut had a relative lower Cd susceptibility risk (15-17% Cd in MAP) with a longer ST50. We suggested that the proposed probabilistic risk assessment framework can incorporate the elimination-detoxification-recovery scheme to help government based biomonitoring and bioassessment programs to prevent potential aquatic ecosystems and human health consequences. 相似文献
82.
Carla P.O. de Assis Manoel G.C. Gondim Jr. Herbert A.A. de Siqueira Cláudio A.G. da Câmara 《Journal of Stored Products Research》2011,47(4):311-315
The fumigant activity of essential oils from Cinnamomum zeylanicum, Eugenia uniflora, Eugenia uvalha, Melaleuca leucadendra, Piper marginatum, and Schinus terebinthifolius was evaluated for control of the mites Tyrophagus putrescentiae (Schrank) and Suidasia pontifica Oudemans. The average mortality, after 24 h of exposure to oil of C. zeylanicum at the highest concentration tested (50 μL/L of air), was 97.7 and 92.9% for T. putrescentiae and S. pontifica, respectively. Mortality of the two species at the same concentration of S. terebinthifolius was 86.7 and 100%, respectively. As measured by LC50, the most toxic oil for T. putrescentiae was eugenol (0.23 μL/L air) followed by C. zeylanicum (0.82 μL/L air), E. uvalha (3.71 μL/L air), and S. terebinthifolius (8.25 μL/L air). The most toxic oil for S. pontifica was eugenol (0.57 μL/L air) followed by C. zeylanicum (1.75 μL/L air), S. terebinthifolius (4.87 μL/L air), and E. uvalha (11.09 μL/L air). Both mite species responded faster to S. terebinthifolius than to the other essential oils. 相似文献
83.
分析了处于交变磁场中的磁性杂质颗粒的受力情况,比较了由交变磁场和稳恒磁场产生的磁场力。结果表明这两种力的本质相同,可以统一起来,而且磁性杂质颗粒在其驱动下的运动规律也相同。Al-Si合金中的富铁相杂质是弱磁性,电磁力和磁场力都可以促使其运动,电磁分离试验结果表明,当磁感应强度大于145mT时,电磁力起主要作用,杂质颗粒向分离器内侧运动;当磁感应强度小于120mT时,磁场力起主要作用,杂质颗粒向分离器侧面运动,据此可以指导分离器的结构设计。 相似文献
84.
C.M.Cheng C.P.Chou I.K.Lee I.C.Kuo 《材料科学技术学报》2006,22(5):685-690
This study investigates the susceptibility of hot cracking and weldment heat treatment of Haynes 230 superalloy. The Varestriant test was conducted to evaluate this susceptibility. Welding was performed by gas tungsten arc welding (GTAW) and plasma arc welding (PAW) with stress relief heat treatment and solid solution heat treatment. A tensile test is then performed to measure the changes in the mechanical properties of the heattreated material. The results indicate that the number of thermal cycles does not affect the susceptibility of Haynes 230 superalloy to hot cracking. However, it does increase the strain. In weldment of heat treatment, stress relief annealing increases the yield strength and tensile strength of the welded parts. The section of the tensile specimens shows fibrous fractures on the welded parts, regardless of whether they are heat-treated. 相似文献
85.
Experimental data on the real (x′) and imaginary (x″) parts of AC magnetic susceptibility as a function of DC bias field (H) shows the effect of trapped flux in granular highT
c superconductors. The aim was to substantiate our recent theoretical findings on the basis of a two-component critical state
model suitable for granular highT
c superconductors. Stress has been given to understanding the origin of hysteresis inx′(H) andx″(H). It was seen in the experimental data that above a certain value of DC field range irreversibility appears inx′(H) andx″(H) creating hysteresis like loops. Comparison of data with calculated loops shows good agreement.x′(H) andx″(H) curves show considerable asymmetry in presence of trapped flux. 相似文献
86.
This study develops a machine learning method that hybridizes the Least Squares Support Vector Classification (LSSVC) and Bat Algorithm (BA), named as BA-LSSVC, for spatial prediction of shallow landslide. To construct and verify the hybrid method, a Geographic Information System (GIS) database for the study area of Lang Son province (Vietnam) has been employed. LSSVC is used to separate data samples in the GIS database into two categories of non-landslide (negative class) and landslide (positive class). The BA metaheuristic is employed to assist the LSSVC model selection process by fine-tuning its hyper-parameters: the regularization coefficient and the kernel function parameter. Experimental results point out that the hybrid BA-LSSVC can help to achieve a desired prediction with an accuracy rate of more than 90%. The performance of BA-LSSVC is also better than those of benchmark methods, including the Convolutional Neural Network, Relevance Vector Machine, Artificial Neural Network, and Logistic Regression. Hence, the newly developed model is a capable tool to assist local authority in landslide hazard mitigation and management. 相似文献
87.
基于GIS和Logistic回归模型的兰州市滑坡灾害敏感性区划研究 总被引:1,自引:0,他引:1
针对兰州市脆弱的地质环境和频繁发生的滑坡灾害,采用Logistic回归模型,以ArcGIS和SPSS软件为工具,选取地层岩性、断层构造、坡度、地貌、植被覆盖度、7~9月平均降水、道路(公路、铁路)作为滑坡灾害影响因子。首先对每个影响因子分级并计算每个因子指标值,然后在ArcMap中对影响因子图层进行叠加操作,最后在SPSS软件中运用Logistic回归方法,计算出每个影响因子的系数值并建立Logistic回归模型。根据Logistic回归模型在ArcMap中绘制兰州市滑坡灾害敏感性区划图,区划图和实际的滑坡分布情况基本吻合。模型的Kappa系数值和ROC曲线下面积值(AUC值)分别为0.623和0.709,两种方法的检验结果均表明模型模拟效果较好,能应用于兰州市滑坡灾害敏感性区划研究中。 相似文献
88.
以沙特中质油的减渣及其丙脱沥青为原料制取高等级道路石油沥青的研究表明,所制取的沥青产品,抗热老化性理想,性能指标在路面使用温度条件下比较稳定,使用性能与国外高等级道路石油沥青相当,符合国内、外有关的技术要求。 相似文献
89.
In this study, the susceptibility of two stored-product insects, Ephestia kuehniella and Tribolium confusum, to gaseous ozone was investigated. Two ozone fumigation methods were used, an empty space fumigation with only one flush of ozone treatment held for 2 h, and a reflush ozone treatment at 30-min intervals for 5 h in the presence of 2 kg wheat, with an initial ozone concentration of 13.9 mg/L. Toxicity data for empty space ozone treatments indicated a remarkable difference in susceptibility between the life stages of E. kuehniella and T. confusum. For E. kuehniella, empty space ozone treatment resulted in complete mortality of adults, pupae and larvae, while only 62.5% of the eggs were killed. For T. confusum, ozone treatment resulted in very low mortality of adults, pupae and eggs, ranging from 4.2 to 14.1% while only larvae had a high mortality (74%). Generally T. confusum was more tolerant to ozone treatment than E. kuehniella. Ozone flush treatment at 30-min intervals for 5 h resulted in almost complete mortality of all life stages of E. kuehniella placed in the top position of 2 kg wheat, whereas eggs of E. kuehniella placed in the bottom position of 2 kg wheat were hard to kill. For T. confusum, larvae placed in the bottom position of 2 kg wheat were easily killed, whereas eggs, pupae and adults survived. 相似文献
90.
A total of nine promising varieties including five desi type and four kabuli type of chickpeas were screened against pulse bruchid under free-choice conditions at Post Harvest Technology Centre, Bapatla. The chickpeas were studied for their physical characters and biochemical constituents, and the extent of influence on insect preference and development was established through correlation and regression analyses. The varieties; NBeG 511, JAKI 9218 and JG 11 which had less numbers of eggs and adult emergence, with low per cent grain damage were found to be desi type and possessed less test weight with higher seed coat thickness. Similarly the varieties; NBeG 458, NBeG 471 and KAK 2 which recorded higher oviposition, adult emergence and grain damage were found to have thin seed coat and larger seed size. Thus, test weight of the grains showed significant positive correlation to adult emergence and grain damage while seed coat thickness showed the negative correlation. Chickpea grains with higher sugar and lower phenol contents were found to be more susceptible to bruchids. Though there were significant differences in the contents of biochemical constituents of chickpeas of these cultivated varieties, they could not exert significant influence on bruchid development. 相似文献