Estimating cadmium concentration in the edible part of Capsicum annuum using hyperspectral models.

Hyperspectral remote sensing can be applied to the rapid and nondestructive monitoring of heavy-metal pollution in crops. To realize the rapid and real-time detection of cadmium in the edible part (fruit) of Capsicum annuum, the leaf spectral reflectance of plants exposed to different levels of cadmium stress was measured using hyperspectral remote sensing during four growth stages. The spectral indices or bands sensitive to cadmium stress were determined by correlation analysis, and hyperspectral estimation models for predicting the cadmium content in the fruit of C. annuum during the mature growth stage were established. The models were cross validated by taking the sensitive spectral indices in the bud stage and the sensitive spectral bands in the flowering stage as the input variables. The results indicated that cadmium accumulated in the leaves and fruit of C. annuum and leaf cadmium content in the three early growth stages were correlated with the cadmium content of the pepper in the mature stage. Leaf spectral reflectance was sensitive to cadmium stress, and the first derivative of the original spectral reflectance was strongly correlated with leaf cadmium content during all growth stages. Among the established models, the multiple regression model based on the sensitive spectral bands in the flowering stage was optimal for predicting fruit cadmium content of the pepper. This model provides a promising method to ensure food safety during the early growth stage of the plant.

[Evaluation of urban human settlement quality in Ningxia based on AHP and the entropy method].

As one of the key indicators of the urbanization and the sustainable development of cities, urban human settlement quality has been a hot issue. In this paper, an evaluation system containing indicators related to four aspects (ecological, social, humanities and economic environments) was established to assess the urban human settlement quality in five main cities in Ningxia Hui Autonomous Region, Northwest China. After calculating each indicator' s weight in the evaluation system through AHP and the entropy method, the quality of urban human settlement was analyzed. Results showed that Yinchuan had a score of 0. 85 for the quality of human settlement, Shizuishan 0.62, Wuzhong 0.43, Zhongwei 0.33, and Guyuan 0.32, respectively. Shizuishan got the highest score in the eco-environment aspect, and Yinchuan had the highest scores for social, humanities and economic environments. Zhongwei and Guyuan had relatively low scores in all the four urban human settlement aspects. Coordination analysis showed that internal coordination was moderate for Yinchuan (0.79) and Shizuishan (0.72), and relatively good for the other cities. However, coordination was relatively poor among the five cities, especially in social environment (0.48). These results suggested that an unsatisfied situation existed in terms of the urban human settlement quality in Ningxia, and that corresponding measures should be taken to accelerate the development of vulnerable indicators, so as to coordinate all the urban human settlement aspects within and among cities.