Wells, fields and the emergence of early-to-middle Holocene villages in the Huai River region, China: Contesting regional similarities and differences on prehistoric water management with new archaeological and palaeo-environmental evidence

The history of water management is closely intertwined with evolution of social structures. In particular, the emergence of rice farming and transition to sedentary life contributed significantly to the development of water management practices, with increasing labour and economic investments to build and operate water-management infrastructures. Here we present archaeological, archaeobotanical and geoarchaeological evidence of early water management obtained from the excavations of three early-to-middle Holocene sites in the upper and middle Huai River region (UMHR), including Hanjing from Sihong County of Jiangsu Province and Xielaozhuang and Zhangwangzhuang from Luohe City and Zhumadian City of Henan Province. Our 14C dates suggest multiple episodes of regional inhabitation in the UMHR region. Our results also reveal that the wells at Xielaozhuang represent some of the earliest attempts to ensure water consumption in the village, and importantly, the rice-field-like structures at Hanjing and Zhangwangzhuang are evidence of a more systematic effort to modify and transform local landscapes for rice cultivation and related economic activities. In line with the results from published phytolith studies, we found that the early experiment of rice cultivation altered local soil and hydrological conditions at these sites. These early forms of rice fields share some similarities in micro-and-macro- morphologies and represent successful adaptations to the low-lying plains that continued to have fluctuating hydrological regimes. The construction and operation of these wells, moats and rice-field-like structures stimulated collaboration beyond individual households and groups in these early-to-middle Holocene villages in the UMHR region and thus would have had profound social and economic ramifications

Ecological Sensitivity of Urban Agglomeration in the Guanzhong Plain, China

In the past two decades, China’s urbanization has advanced rapidly. In 2018, Xi’an was successfully selected as a national central city, and the Guanzhong Plain urban agglomeration (GZPUA) is emerging rapidly due to Xi’an. This study focuses on the current ecological status of the region and how to strike a balance between economic development and ecological protection. This study uses the ecological vulnerability of the Guanzhong urban agglomeration as a starting point to investigate the changes in its spatial and temporal distribution of ecological vulnerability and the primary driving factors, as well as to investigate the interaction between the changes in ecological vulnerability and urban agglomeration development in the GZPUA region. Using the “sensitivity–elasticity–pressure (SEP)” assessment framework model, this paper selects the spatial distribution data of natural, social, and economic sources in 2000 and 2020 based on the ecological environment characteristics of GZPUA. By using spatial principal component analysis, this paper quantitatively evaluates the ecological vulnerability changes of GZPUA in two periods, 2000 and 2020, with 1000 m × 1000 m raster as the evaluation unit, classifies the ecological vulnerability of the area into levels, and conducts a sub-regional in-depth study from different administrative regions. This research helps to comprehend the change in ecological environment quality in the GZPUA and provides a basis for ecological environment management decisions in the region. The results showed that (1) the ecological vulnerability of the Guanzhong Plain urban agglomeration as a whole is moderate, with the highest ecological vulnerability index (EVI) value of 0.89 and the lowest EVI value of 0.087 in 2000, and the highest EVI value of 0.93 and the lowest EVI value of 0.082 in 2020. The percentage of areas with the highest ecological vulnerability (moderate or severe) was 5.07% in 2000 and 15.11% in 2020. (2) The variation scope of the integrated EVI in the study region is 1.78–4.96 (2000) and 1.81–4.99 (2020), among which the EVI values in Xi’an, Bei Lin, Lian Hu, and Xin Cheng are the highest and the EVI values in Tai Bai, Zhou Zhi, and Feng Xian are the lowest. (3) In the central region of GZPUA, the spatial variation of CEVI is distributed in a circle that is highly congruent with the region’s economic and population development characteristics, whereas the spatial variation of CEVI in the southern mountainous region of the study area is primarily constrained by the topography and natural conditions. This region has low CEVI because of the high mountains and thick forests, which is a crucial ecological barrier for the GZPUA. (4) The EVI, ecological sensitivity index (ESI), ecological elasticity index (EEI), and ecological pressure index (EPI) have a strong relationship with land use. Among them, farmland and built-up land showed highly significant correlations with the EVI, ESI, EEI, and EPI (p < 0.01)

Magnetism in Cr-doped ZnS: Density-functional theory studies

We investigated the magnetism and aggregation trends in cubic Zn1-xCrxS using the density-functional theory calculations.We demonstrate that all studied configurations show ground state half-metallic ferromagnetism (HMF); and Cr impurities are energetically favorable to planar cluster into delta-doping structures. The single-layer delta-doping structures of Zn0.75Cr0.25S and Zn0.875Cr0.125S show ferromagnetic stabilization energies (\Delta E_AF) of 0.551 and 0.561 eV/Cr-Cr pair, respectively. The half-layer delta-doping structure of Zn0.875Cr0.125S and double-layer delta-doping structure of Zn0.75Cr0.25S show \Delta E_AF of 0.394 and 0.166 eV/Cr-Cr pair, respectively. Furthermore, our studies indicate that the cubic ZnS/CrS heterostructure, one extreme situation of the delta-doping structure, also shows ground state HMF. The origin of HMF is discussed using a simple crystal field model. Finally, we anticipate the potential spintronics application of Zn1-xCrxS.Comment: 13 pages, 4 figure

Path Planning for Autonomous Vehicle Based on a Two-Layered Planning Model in Complex Environment

The autonomous vehicle consists of perception, decision-making, and control system. The study of path planning method has always been a core and difficult problem, especially in complex environment, due to the effect of dynamic environment, the safety, smoothness, and real-time requirement, and the nonholonomic constraints of vehicle. To address the problem of travelling in complex environments which consists of lots of obstacles, a two-layered path planning model is presented in this paper. This method includes a high-level model that produces a rough path and a low-level model that provides precise navigation. In the high-level model, the improved Bidirectional Rapidly-exploring Random Tree (Bi-RRT) based on the steering constraint is used to generate an obstacle-free path while satisfying the nonholonomic constraints of vehicle. In low-level model, a Vector Field Histogram- (VFH-) guided polynomial planning algorithm in Frenet coordinates is introduced. Based on the result of VFH, the aim point chosen from improved Bi-RRT path is moved to the most suitable location on the basis of evaluation function. By applying quintic polynomial in Frenet coordinates, a real-time local path that is safe and smooth is generated based on the improved Bi-RRT path. To verify the effectiveness of the proposed planning model, the real autonomous vehicle has been placed in several driving scenarios with different amounts of obstacles. The two-layered real-time planning model produces flexible, smooth, and safe paths that enable the vehicle to travel in complex environment. Document type: Articl

Letter of Intent: Jinping Neutrino Experiment

Jinping Neutrino Experiment (Jinping) is proposed to significantly improve measurements on solar neutrinos and geoneutrinos in China Jinping Laboratory - a lab with a number of unparalleled features, thickest overburden, lowest reactor neutrino background, etc., which identify it as the world-best low-energy neutrino laboratory. The proposed experiment will have target mass of 4 kilotons of liquid scintillator or water-based liquid scintillator, with a fiducial mass of 2 kilotons for neutrino-electron scattering events and 3 kilotons for inverse-beta interaction events. A number of initial sensitivities studies have been carried out, including on the transition phase for the solar neutrinos oscillation from the vacuum to the matter effect, the discovery of solar neutrinos from the carbon-nitrogen-oxygen (CNO) cycle, the resolution of the high and low metallicity hypotheses, and the unambiguous separation on U and Th cascade decays from the dominant crustal anti-electron neutrinos in China.Comment: Proposal for the Jinping Neutrino Experimen

Structure and Magnetism in Mn Doped Zirconia: Density-functional Theory Studies

Using the first-principles density-functional theory plan-wave pseudopotential method, we investigate the structure and magnetism in 25% Mn substitutive and interstitial doped monoclinic, tetragonal and cubic ZrO2 systematically. Our studies show that the introduction of Mn impurities into ZrO2 not only stabilizes the high temperature phase, but also endows ZrO2 with magnetism. Based on the simple crystal field theory (CFT), we discuss the origination of magnetism in Mn doped ZrO2. Moreover, we discuss the effect of electron donor on magnetic semiconductors, and the possibility as electronic structure modulator.Comment: 10 pages, 3 figures, 26 reference

Development of a growth-coupled selection platform for directed evolution of heme biosynthetic enzymes in Corynebacterium glutamicum

Heme is an important tetrapyrrole compound, and has been widely applied in food and medicine industries. Although microbial production of heme has been developed with metabolic engineering strategies during the past 20 years, the production levels are relatively low due to the multistep enzymatic processes and complicated regulatory mechanisms of microbes. Previous studies mainly adopted the strategies of strengthening precursor supply and product transportation to engineer microbes for improving heme biosynthesis. Few studies focused on the engineering and screening of efficient enzymes involved in heme biosynthesis. Herein, a growth-coupled, high-throughput selection platform based on the detoxification of Zinc-protoporphyrin IX (an analogue of heme) was developed and applied to directed evolution of coproporphyrin ferrochelatase, catalyzing the insertion of metal ions into porphyrin ring to generate heme or other tetrapyrrole compounds. A mutant with 3.03-fold increase in kcat/KM was selected. Finally, growth-coupled directed evolution of another three key enzymes involved in heme biosynthesis was tested by using this selection platform. The growth-coupled selection platform developed here can be a simple and effective strategy for directed evolution of the enzymes involved in the biosynthesis of heme or other tetrapyrrole compounds