Quantifying the effects of plant litter in the topsoil on the soil detachment process by overland flow in typical grasslands of the Loess Plateau,China

Plant litter can be incorporated into topsoil by a natural process, affecting the soil erosion process. This is a widespread phenomenon in erosion-prone areas. This study was conducted to investigate the effect of litter incorporation on the process of soil detachment on the Loess Plateau, China. Four common plant litters (Bothriochloa ischaemum L. Keng., Artemisia sacrorum Ledeb., Setaria viridis L. Beauv., and Artemisia capillaris Thunb.) were collected, then incorporated into the silt loam soil at five rates (0.1, 0.4, 0.7, 1.0, and 1.3 kg m⁻²) on the basis of our field investigation. Twenty litter–soil treatments and one bare soil control were prepared. After 50 days of natural stabilization, 30 soil samples of each treatment were collected. We used a flume test to scour the soil samples under six flow shear stress conditions (5.66, 8.31, 12.21, 15.55, 19.15, and 22.11 Pa). The results showed that the different incorporated litter masses and morphological characteristics, such as litter tissue density (ranging from 0.52 to 0.68 g cm⁻³), length density (2.34 to 91.00 km m⁻³), surface area density (LSAD; 27.9 to 674.2 m² m⁻³), and volume ratio (0.003 to 0.050 m³ m⁻³), caused varied soil detachment capacities (0.043 to 4.580 kg·m⁻²·s⁻¹), rill erodibilities (0.051 to 0.237 s m⁻¹), and critical shear stresses (2.02 to 6.83 Pa). The plant litter incorporated within the soil reduced the soil detachment capacities by 38%–59%, lowered the rill erodibilities by 32%–46%, and increased the critical shear stresses by 98%–193% compared with the bare soil control. The soil containing B. ischaemum (L.) Keng. litter was more resistant to erosion. By comparing different parameters, we found that the contact area between the litter and soil was the main factor affecting the soil detachment process. The soil erosion resistance increased with the increasing contact area between the soil and litter. Furthermore, the litter incorporation effect on rill erodibility can be comprehensively reflected by LSAD (R² = .93; Nash–Sutcliffe efficiency = 0.79), which could be used to adjust the rill erodibility parameter in physical process-based soil erosion models.     

高放射性废物矿物固化体的特性

对高放射性废物（ＨＬＷ）矿物固化体的性能作了详细分析,并对ＨＬＷ矿物固化体和玻璃固化体的性质和两者的制作过程作了简单比较。体积小、ＨＬＷ组分掺入量高,浸出率低和制作过程简单是矿物固化体的优势。ＨＬＷ矿物载体的稳定性分析表明它们十分适合地下处置库潮湿和温度变化的环境。虽然单种矿物只能处理部分ＨＬＷ组分,但多种矿物集合起来就可以整体荷载全部的ＨＬＷ组分。     

Boron Isotopic Composition of Halite from 46-m-long Sediment Core in the Qarhan Salt Lake,Western China

正Previous studies have investigated the boron isotopic composition of salt lake brines in the Qaidam Basin,western China.However,the research on boron isotopic composition of halite is very limited due to halite’s low     

TEMPORAL AND SPATIAL DIMENSIONS OF NEWLY INCORPORATED MUNICIPALITIES IN THE UNITED STATES*

Scholarly literature on newly incorporated municipalities (nims ) often focuses on why nims form. Instead of asking why nims formed, however, we ask why nims stopped forming. We first establish a temporal context for nims from 1950 to 2010, revealing an 86.2 percent decline in nim formation. The decline, triggered by stricter laws, smaller annexations, declining suburbanization, and boundary ossification, has profound implications for metropolitan fragmentation and public choice. We then establish a state‐level spatial context, revealing distinct high‐nim , low‐nim , and flux states due to boundary ossification, growth, and state/regional policy stimuli such as consolidation efforts, grants, and growth management provisions.     

航次租船合同下与提单有关的滞期费纠纷

从买卖合同、租船合同以及提单的相关规定出发，结合中外典型案例，阐述了航次租约下滞期费纠纷产生的原因，滞期费责任的承担方，提单中的并入条款是否有效、并入的范围及不同法系国家对待并入条款的态度等几个问题，揭示了滞期费纠纷的复杂多变性。     

Why majority-minority cities form: non-White municipal incorporation in the United States, 1990–2010

Forty-four majority-minority cities formed in the United States between 1990 and 2010. Why did these cities form in Black, Hispanic, Asian, Native-American majority and other non-White communities? Do these cities form to escape annexation, improve services, and control land use, as most new cities do? Or are other factors at play, such as race and social justice? Using a detailed content analysis, we explore the genesis of newly incorporated municipalities in non-White communities. Our findings reveal that while most majority-minority cities form due to standard stimuli, some majority-minority cities form in direct response to racism (rebound incorporations, environmental racism, and under-provision of services). Moreover, when compared to all new cities, majority-minority cities form more often due to nuisances and less often due to annexation threats and growth control, thus illuminating the role institutional racism plays in municipal incorporation.