Suchergebnisse

Heavy metals pollution in groundwater and the resulting health risks have always been an environmental research hotspot. However, the available information regarding this topic and associated methods is still limited. This study collected 98 groundwater samples from a typical agricultural area of Songnen Plain in different seasons. The pollution status and sources of ten heavy metals (As, Ba, Cd, Co, Cr (VI), Cu, Fe, Mn, Ni, Pb, and Zn) were then analyzed and compared. In addition, the human health risks assessment (HHRA) model was used to calculate human health risks caused by heavy metals in groundwater. The results revealed that heavy metals were mainly distributed in the northwest of the study area and along the upper reaches of the Lalin river and that the concentrations of heavy metals were higher during the wet season than the dry season. Industrial and agricultural activities and natural leaching are the main sources, and each kind of heavy metal may have different sources. Fe and Mn are the primary pollutants, mainly caused by the native environment and agricultural activities. The exceeding standard rates are 71.74% and 61.54%, respectively based on the Class III of Quality Standard for Groundwater of China (GB/T 14848-2017). The maximum exceeding multiple are 91.45 and 32.05, respectively. The health risks of heavy metals borne by different groups of people were as follows: child > elder > young > adult. Carcinogenic heavy metals contribute to the main risks, and the largest risks sources are Cr and As. Therefore, the government should appropriately restrict the use of pesticides and fertilizers, strictly manage the discharge of enterprises, and control man-made heavy metals from the source. In addition, centralized water supply and treatment facilities shall be established to prevent the harm of native heavy metals.

In the context of uneven development studies of China, urban built-up area changes are the index of the impact of power, as the local government is the only party that is able to acquire agricultural land and convert it to construction urban land. Existing studies generally use statistical data to describe the built-up area changes and struggle to meet the requirement of an updated and inexpensive monitoring of uneven development, especially for western cities with tight budgets. Open access NPP-VIIRS (Suomi National Polar-orbiting Partnership Visible Infrared Imaging Radiometer Suite), NDVI (Normalized Difference Vegetation Index), and nighttime LST (Land Surface Temperature) data ranging from 2015 to 2019 were analyzed with a stratified SVM (Support Vector Machine) method in this study to track urban built-up area changes in Chengdu, one of the biggest cities in Western China. The SDE (Standard Deviation Ellipse) and Moran's I were then applied to evaluate the spatial variations of the built-up area changes. It was revealed that the spatial evolution of built-up area change in Chengdu over the period 2015–2019 demonstrated a "northwest-southeast" spatial expansion pattern, and the change distance in the center of gravity in 2018 and 2019 was greater than that from 2015 to 2017, which reflected the faster uneven development in 2018 and 2019 in Chengdu. The results were verified with finer resolution Landsat-8 OLI images; the high OA (all larger than 92%) and KAPPA (all larger than 0.6) values showed the accuracy of the method. The methodology proposed in this study offers a practical way for cities with tight budgets to monitor uneven development, and this study suggests a further adaption using higher-resolution remote sensing images and field experiments.

Xiangxi Miao embroidery carries the Miao people's past memory and future vision and is also linked to the mysterious Xiangxi Miao witch culture inextricably. This paper analyses the relationship between the culture of myths and legends and the culture of gods and witches and their impacts on Miao embroidery. The culture of myths and legends is mainly reflected in the living of totem worship, the culture of gods and witches includes the worship of multiple gods and the flourishing of the Nuo ritual, which have engraved a special national mark on Xiangxi Miao embroidery.

Hate crimes surged at several points during and after the 2016 U.S. presidential election. Observers argued that hate crimes, especially against Muslims, increased due to inflammatory rhetoric. Did anti-Muslim hate crimes decline after the salience of Muslims receded? Or did emboldening and organizational effects on hate crimes endure? Here, we show that a sudden mid-2017 decline in media discussion of Muslims and in online communities was associated with a large and sustained drop in anti-Muslim hate. At nearly the same time as these shifts, however, we observe an increase in violent hate crimes committed against Jews, and Granger causality tests demonstrate that week-to-week changes in online extremist speech targeting one group versus another also predicted subsequent shifts in hate crimes and bias incidents. Platform-level and within-individual analyses of online social media users suggest that increased anti-Jewish speech was partly driven by far-right communities and extremists who previously promoted anti-Muslim speech.