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The ecosystem service value (ESV) is a critical metric for assessing the construction and protection of the environment. The research into the ESV pattern and the future development trend in the Loess Plateau of Northern Shaanxi is important for the conservation of water and soil and the enhancement of the natural environment in the region. In this study, the variations and distribution patterns of the ESV in the study area from 2000 to 2020 were analyzed, the influence of various natural and social factors on the ESV was quantified, the weight of each factor was analyzed and evaluated using the entropy weighting method, and, finally, a prediction was made regarding how the ESV will develop going forward in this area. The results show that (1) the ESV showed a decreasing trend from 2000 to 2020, with the highest value for soil conservation and the lowest value for food production. Among the 25 districts and counties, Suide County had the lowest ESV per unit area, whereas Huanglong County had the highest. (2) The global positive correlation was clearly visible in the ESV. According to local spatial autocorrelation analysis, the area had a "high-high" agglomeration area in the south and a "low-low" agglomeration area in the middle and north. (3) Among the various influencing factors, population density had the highest weight and the distance from roads had the lowest weight. The impact status of the area generally showed a lighter impact in the southern region and a heavier impact in the northern region. (4) In 2030, the total ESV is predicted to be CNY 4343.6 million in the study area, CNY 39 million lower than that in 2020. [ABSTRACT FROM AUTHOR]

Introduction: Complement system plays an important role in the pathogenesis of idiopathic membranous nephropathy (IMN), however, the relationship between serum complement 4 (C4) and kidney disease progression in IMN is unclear. This study aims to investigate the association of serum C4 level with the risk of kidney disease progression among patients with IMN. Methods: The retrospective cohort assessed 1,254 participants with biopsy-proven IMN from three centers in Xi 'an, Shaanxi Province, China. Baseline serum C4 levels were measured at renal biopsy. The association between baseline serum C4 and the risk of renal function progression, defined as a 30% decline in renal function or end stage renal disease, was evaluated in Cox proportional hazards models. Results: A total of 328 patients with IMN and nephrotic proteinuria were eligible, and 11.3% (37/328) of them attained the renal function progression events after a median follow-up of 51 months (37-59 months). After adjustment for other confounders, a higher value of serum C4 was independently associated with a higher risk of renal function progression event with a hazard ratio (HR) of 4.76 (95% confidence interval [95% CI], 1.77-12.79) per natural log-transformed C4. In reference to the low level of C4, the adjusted HRs were 2.72 (95% CI, 1.02-7.24) and 3.65 (95% CI, 1.39-9.60), respectively, for the median and high levels of C4 (P for trend=0.008). Additionally, the results were robust and reliable in the sensitivity and subgroup analyses. Conclusion: Among patients with IMN and nephrotic proteinuria, serum C4 at renal biopsy is an independent predictor for kidney disease progression regardless of other confounders. [ABSTRACT FROM AUTHOR]

Widely distributed in North China, Ordovician karst is characterized by having high thickness, nonuniform aquosity, and significant water pressure-bearing properties. Deep mining in North China is threatened by associated water hazards; hence, research on the hydrogeological characteristics of deep Ordovician karst is needed. In this study, the Weibei coalfield in Shaanxi Province, China, was selected as the study area, especially mines in the Hancheng and Chenghe mining areas. In situ experiments, including water pumping, water drainage, water injecting and water pressure, and laboratory experiments, were conducted to study the hydrogeological characteristics of the Ordovician karst top in the study area. A comprehensive analysis was conducted on controlling factors for the development of the Ordovician karst top in the study area, and a method for evaluating the water inrush risk in coal mining areas based on karst hydrogeological characteristics was proposed. The research results indicated that the Ordovician karst top in the study area was characterized by heterogeneity, vertical zonation, and partially filled properties, which were mainly controlled by two factors: sedimentation and tectonism. The hydrogeological conditions of the Ordovician karst could be divided into three types: nonfilled and nonsignificant tectonism, filled and nonsignificant tectonism, and significant tectonism. Among them, the filled and nonsignificant tectonism type Ordovician karst top type had a filling thickness of 20 m. Based on karst hydrogeological characteristics, the methods were proposed to evaluate the water inrush risk in the coal mining floor. The practical tests verified the methods. [ABSTRACT FROM AUTHOR]