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Earthen sites (i.e., ancient earthen buildings) with important historical, cultural, artistic, social, and scientific value have been seriously damaged. Soil treatment with chemical additives can decrease the degradation rate of earthen sites. In the past, polyvinyl alcohol (PVA) and quicklime as chemical additives were studied separately for the protection of earthen sites. In arid and semi-arid northwest China, the early strength of the lime-treated soil may be insufficient due to an inappropriate reaction environment, and the PVA as the additive can quickly increase the soil strength. However, calcium carbonate has been proven to not be decomposed for hundreds of years, while there is still a lack of experimental evidence to show that the PVA cannot be decomposed in decades. The PVA and lime as the additives show the potential to make up for the defects each other. Therefore, the physical and mechanical properties of the PVA and lime composite soil are analysed, and the microscopic properties of the composite soil are discussed in this study. The results show that the addition of the PVA decreases water vapour permeability and pore size, which causes a delay in the carbonization reaction of lime, but it acts as a cementing agent to improve soil strength before the lime appropriately reacts. The addition of quicklime can decrease the hydrophobicity of the PVA-treated soil. The mixing of these two materials is conducive to the colour control of the sample. For the composite soil applied to earthen sites in northwest China, the optimal ratio is 10% lime and 1.0% PVA. [ABSTRACT FROM AUTHOR]

• The spatial features of rammed pits of the Ming Great Wall were explored. • The representative micro slopes with true rammed pit morphology were found by RF. • The shapes and distribution of rammed pits show more regularity than randomness. • The regularity of rammed pits is derived from the standardized ramming technique. • The rounded heads and rough surfaces of rammers are reflected by rammed pit shapes. In Northwestern China, the Ming Great Wall generally involves multiple layers of rammed earth, and rammed pits with regular spatial characteristics are always distributed on the horizontal interfaces between rammed layers. Obviously, the spatial regularity of rammed pits cannot only reflect the level of ramming technique in the Ming dynasty, but also control the geotechnical properties of rammed layer interfaces (RLIs). Hence, in the present study, one typical RLI with visible rammed pits was obtained from the Ming Great Wall in Yongchang County, Northwestern China, and the corresponding point cloud data were collected by 3D scanning technique. Then, this RLI was reconstructed using numerous micro slopes in ArcGIS, and the distribution maps of micro-slope heights, angles, plan curvatures and profile curvatures were produced as well. Based on these distribution maps and Random Forest (RF) algorithm, those micro slopes which can reflect the true rammed pit morphology (called the representative micro slopes) were identified, and ten zones where the representative micro slopes concentrate were selected as effective analysis domains. Furthermore, within effective analysis domains, the contour lines were generated to show the outline features of rammed pits, and the values of micro-slope heights, angles, plan curvatures and profile curvatures were statistically analyzed to reveal the surface features of rammed pits. Moreover, the distribution features of rammed pits were exhibited by their centroid positions, which can be calculated by the corresponding contour line shapes. Ultimately, this study indicates that rammed pits of the Ming Great Wall show more regularity than randomness in terms of geometric shapes and spatial distribution. Concretely, the outlines of most rammed pits approximate the circular or elliptical shapes. All the rammed pit surfaces are rough rather than smooth, and most of them can be mathematically expressed by quadratic polynomial equations. As for the distribution features, rammed pits are overall distributed in the triangular shapes, and distances between the equivalent centroids of adjacent rammed pits range from 8.95 cm to 17.86 cm. These findings prove that standardized ramming technique was applied in the Ming dynasty, resulting in high-quality construction of the Great Wall. Meanwhile, the rammers used to compact earthen materials possess rounded heads. However, the imperfect polishing of rammers and the inevitable operational errors could also lead to slight spatial randomness of rammed pits. [Display omitted] [ABSTRACT FROM AUTHOR]

The Loess Plateau has been a focus of public discussion and environmental concerns over the past three decades. In this study, in order to investigate the effect of OCP pollution in water of the Beiluo River, concentrations of 25 OCPs at 17 locations in the water were examined. The results showed that the concentration of ∑OCPs in the water ranged from 1.76 to 32.57 ng L−1, with an average concentration of 7.23 ng L−1. Compared with other basins in China and abroad, the OCP content in the Beiluo River was at a medium level. Hexachlorocyclohexane (HCH) pollution in the Beiluo River was mainly from the mixed input of lindane and technical HCHs. Dichlorodiphenyltrichloroethane (DDT) pollution was mainly from the mixed input of technical DDTs and dicofol. Most of the OCP pollution came from historical residues. The risk assessment results showed that hexachlorobenzene (HCB) and endosulfan had high ecological risks in the middle and lower reaches of the Beiluo River. Most residual OCPs were not sufficient to pose carcinogenic and non-carcinogenic health risks to humans. The results of this study can provide a reference for OCP prevention and control and watershed environmental management. [ABSTRACT FROM AUTHOR]

The precipitation accelerates the migration of water and salt in the soil, and aggravates the deterioration of saline earthen sites. Based on the freeze-thaw tests of soil column, the water and salt migration process of earthen sites in northwest China after rainfall in early winter and snowfall in late winter was simulated. The results show that when providing the same quality of rain or snow, the water basically migrated to all parts of the soil column under the initial condition of rainfall infiltration, while the water redistribution range after snowmelt infiltration was just the upper part of the soil column. With the infiltration and evaporation of water, the salt in the surface layer of soil column leached downward and then migrated upward. After 20 freeze-thaw cycles, the contents of SO2–4 and Cl− in the surface layer of soil column under rainfall condition were 89.13% and 99.27% of the initial value, respectively, while those under snowmelt condition were 61.58% and 60.65%, respectively. Snowmelt caused the soil surface to form rolled mud and salt efflorescence, while rainfall led to the formation of crust on the top surface of the soil column and saline zone at the bottom. [ABSTRACT FROM AUTHOR]

Earthen sites with important historical, cultural, artistic, social, and scientific values have been seriously damaged. Basal erosion, which is caused by soluble salts, water runoff, and sand-driving wind, is an extremely threatening erosion pattern for earthen sites. A cushion layer which has a damp-proofing function and good physical and mechanical properties can effectively decrease basal erosion. The primary aim of this study is to investigate material selection for the hydrophobic cushion layer for earthen sites in northwest China. The results indicate that cooked tung oil and sticky rice liquid, traditionally used in China, cannot meet the fundamental requirements of sufficient hydrophobicity for the cushion layer. Although polyvinyl alcohol (PVA) solution and tung oil exhibit similar properties in terms of soil hydrophobicity, water vapour permeability, water resistance, surface hardness, and colour difference for samples with 0.0-1.0% content, the PVA solution is significantly better than tung oil in unconfined compressive strength, deformation modulus, wave velocity, and viscosity. Therefore, the PVA solution should be preferentially selected as a hydrophobic cushion layer material according to the results of this work. When the mixing method is adopted, 0.6-1.0% PVA content is the best choice. [ABSTRACT FROM AUTHOR]

Purpose: More than 2 billion tons of construction waste soil are generated every year in China, leading to waste and degradation of land resources. This study aims to develop a reinforcement technology for granite residual soil, the common type of construction waste in China, evaluate the reinforcement properties, and investigate the mechanism. Method: In this study, the polymer SH, glass fiber, and granite residual soils were mechanically mixed to prepare specimens for impact resistance tests. Additionally, the specimens obtained were characterized using a combination of techniques including X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Results: The low-velocity impact test showed that the impact resistance of granite residual soil is highly related to the content of SH. When the content reaches 3.5%, the impact resistance is the best. Results of characterization revealed that kaolinite plays an important role in the reinforcement system, which can be summarized into the following: (1) the hydrophobic group (C–C) on the SH molecular chain is bridged on the surface of kaolinite, transforming kaolinite from hydrophilic to hydrophobic; thus, the disintegration characteristic of GRS in water was moderated. (2) The pores between kaolinite are also filled by SH molecular chains. (3) In particular, the frictional engagement of kaolinite and glass fiber also enables the tensile strength of glass fiber to be exerted. Conclusion: These findings provide possibilities for the effective recycling of granite residual soil on a vast scale and the sustainable development of construction waste soils. [ABSTRACT FROM AUTHOR]

Since 2006, with the implementation of a series of national research projects in the field of earthen site conservation, the Chinese theoretical foundation and technological conservation system for the protection of earthen sites in arid environments has gradually formed. However, there are some global problems such as an unclear relationship between characteristics of diseases on sites and their existing environment, unclear deterioration mechanisms under multi-field coupling, immature stability control technology under dynamic loading, the poor suitability of protection process quality assessment equipment, and a lack of systematic research on comprehensive protection synergy mechanisms. On the basis of summarizing the research achievements in the field of earthen site conservation in China for more than 30 years, and a large number of practical experiences in earthen site reinforcement engineering, this paper expounds the multi-field coupling characteristics of earthen site construction technology, the climatic environment, and dynamic loading and protection measure activities, clarifies the main characteristics of the protection of earthen sites in China at present, puts forward the key scientific and technical problems existing in the conservation of earthen sites, constructs a picture of the research on the conservation of earthen sites under the action of multi-field coupling, and discusses the protection projects of earthen sites under different environments. We hope the technological system can provide support for the transformation of earthen site conservation from the rescuing conservation stage to the stage of both rescuing and preventive conservation, and move the foundation of earthen site conservation towards the stage of preventive protection. [ABSTRACT FROM AUTHOR]

The plaster of the wall paintings at Mogao Grottoes is all made of earth, and the migration of water and salt in this kind of plaster is one of the most important factors that cause the deterioration of the wall paintings. However, the characteristics of the migration in the earthen plaster, which are quite crucial for the research on the formation mechanism of deteriorations and the conservation treatments, have not been fully comprehended yet. In order to study the migration rule of water and salt in the plaster, different types of simulated plasters were made according to the material composition of the plaster at Mogao Grottoes. Through a series of experiments and analyses, pore-size distribution, microstructure and capillary migration rules of the plasters were characterized. Due to the difference in capillary performance, a capillary barrier effect will occur at the interface between the coarse plaster and the fine plaster. After the capillary migration, the salt is more likely to accumulate on the area of the capillary front, which will directly damage the paint layer. And the salt-water migration process inside the plaster will make the plaster structure loose and porous. Therefore, it is important to prevent rain infiltration and the rising damp after rainfall for wall painting conservation. [ABSTRACT FROM AUTHOR]

Having extremely high artistic, scientific and social values, earthen sites are widely distributed in China and are important human cultural relic resources. Due to accumulated natural erosions (from rain and wind) and human activities (destructive activities of human beings in history and modern times), however, earthen sites have been greatly damaged, and many sections have even been absent, so that they are seriously threatened by extinction. Under these circumstances, acquiring the conservation status of earthen sites is a vital prerequisite for the subsequent targeted protection. In this paper, as a world-renowned heritage site, the castles of the Ming Great Wall located in Qinghai Province were selected as the research object. A novel indicator, namely the linear absent section ratio (L-ASR), was proposed, and its value was classified into five levels to quantitatively characterize the specific conservation status of such sites, including excellent (E) (0–10%), good (G) (10–25%), fair (F) (25–50%), poor (P) (50–75%), and very poor (VP) (75–100%). Based on the assessment results, the castles with excellent status constituted the minimum proportion, while the castles with very poor status represented the largest percentage, reflecting the grave situation of earthen sites. Furthermore, by applying population distribution models to the linear fitting combined with the population density (PD), a positive correlation between PD and L-ASR was obtained to reveal the anthropogenic influence on the destruction of earthen sites. Principal component analysis (PCA) was utilized to provide a far richer understanding of which factors correlate most strongly with deterioration. This study provides a new thought to quantitatively characterize the preservation conditions of earthen sites and also indicates the effect of human activities on the damage of earthen sites from a population density perspective, which is potentially used for the analysis of more various types of architecture with different construction techniques. Hence, this approach is beneficial to the overall damage assessment of earthen sites, and also meaningful to their further preservation and protective planning. [ABSTRACT FROM AUTHOR]

To clarify the sliding mechanism of a landslide, the shear behavior characteristics of slip zone soil are always vital. In the Northwest of China, thousands of landslides generally develop in three main types of slip zone soil, i.e., Quaternary loess, weathered Mesozoic-Cenozoic mudstone, and weathered Mesozoic-Paleozoic phyllite. In the present study, the shear behavior characteristics of these three kinds of slip zone soil were investigated through direct shear tests and their implications for the sliding mechanisms of landslide were also discussed. It was found that, in general, an abrupt failure of loess landslide could be related to the strong strain-softening behavior of loess in the direct shear test, while the ductile shear behavior of weathered mudstone and phyllite coincided with the creep deformation of the corresponding landslides. The residual friction angle of slip zone soil varied with the soil type and its mineral composition, and the lowest residual friction angle about 11.5° could be found in weathered phyllite (SET) with graphite. Compared with the previous research, it is interesting to find that the residual friction angles of mudstone and phyllite in the present study accorded reasonably with the empirical correlations proposed by Wen et al. (2007) for weak rocks in the Three Gorges area, China. [ABSTRACT FROM AUTHOR]

• Dissolution of calcite, plagioclase and K-feldspar caused major elemental loss (to solutions) of Na, K and Ca in the BTG. • Weathering patterns were linked to seasonal hydrological changes affected by both reservoir filling and groundwater system. • More evidence for surface illitization of smectite in natural alkaline environments was provided. Alkaline environments are common in arid and semi-arid regions in northwestern China and have preserved quantities of rock heritages along the Silk Road. In contrast to the frequently reported weathering mechanism of stone heritages in acidic conditions, mineral weathering mechanism (especially the transformation mechanism of smectite) in natural alkaline environments still remains to be evaluated. To deepen the understanding of weathering in such an environment, research idea from critical zone science was applied to investigate the element transport and mineral transformation from protolith (interbedded sandstone and conglomerate) to regolith in a world cultural heritage, Bingling Temple Grottoes (BTG), in northwestern China. From geochemical and mineralogical characterizations on boreholes, excavated profiles, fractures and cliff surface, we found that dissolution of calcite, plagioclase (anorthite, albite) and K-feldspar (orthoclase) caused major elemental loss of Na, K and Ca (to aqueous solution) in the BTG, and elements of Mg and Fe mostly retained in solid materials. Characterizations on the cliff surface demonstrated higher extents of element depletion and mineral weathering and lower ultrasonic P -wave velocities in sandstone than in conglomerate, and in the bottom sandstone layers (located in the capillary zone and exposure to rain scouring) than in upper sandstone layers (located in the cave and free of precipitation). The transformation of smectite from protolith to regolith follows the sequential reactions: dehydrated smectie → bihydrated smectite → randomly interstratified illite/smectite → illite. Such transformation pathway is favored by alkaline pH and wetting–drying cycles frequently occurred at the BTG. Typical weathering patterns such as clay swelling damage, efflorescence, salt precipitation, etc., are highly-linked to seasonal changes in the hydrological process influenced by both reservoir construction and groundwater system. Our study provides more evidence for the illitization of smectite in natural alkaline environments and highlights the hydrological impacts on weathering patterns of rock grottoes. [ABSTRACT FROM AUTHOR]

The Subashi Buddhist Temple Ruins, which contain a lot of coarse-grained soils, have been severely damaged by surface weathering. Modified polyvinyl alcohol (SH) which can improve the mechanical properties of fine-grained earthen ruins has never been reported in the protection of coarse-grained earthen ruins, and thus, it is of great practical significance to investigate the impregnation and consolidation effects of SH solution on coarse-grained soils. First, the characteristic changes obtained by SH impregnation with respect to consolidation radius, impregnation rate, impregnation time, and cumulative impregnation were analysed for soil specimens with different dry densities and grain gradations. Then, disintegration, drying–wetting cycle, and freeze–thaw cycle experiments were carried out, and the results of these experiments were analysed. Finally, the impregnation and consolidation effects of the SH solution were evaluated together. The feasibility of protecting the Subashi Buddhist Temple Ruins with SH by impregnation was studied, and it is suggested that the methods of surface spraying and borehole impregnation for anti-weathering should be combined to protect these ruins. [ABSTRACT FROM AUTHOR]

Numerous ancient sandstone grottoes remain in northwest and central China, and weathering issues have significantly influenced their preservation conditions. The dramatic naturally cyclic changes in water content and temperature in the environment have been considered to be the main drivers of the physical weathering that commonly occurs at these archaeological sites. Therefore, comparing and understanding the behaviors of sandstone with different weathering degrees under variable environmental conditions would be helpful for further study on predicting the type, location and extent of deterioration of sandstone relics in a small region (such as the surrounding rock of grottoes). This study examines Cretaceous sandstones with two weathering degrees from Bingling Temple Grottoes, China. Standard thin section photomicrographs provide petrographic and mineralogical data and show that the sandstones have identical lithologies. Three types of specifically designed frost weathering tests are then conducted on the samples. After every six weathering cycles, the weathering processes are suspended, and the corresponding parameters, such as dry weight loss, dry density, effective porosity, porosity, P wave velocity, surface hardness and drilling resistance, are measured. At the end of the weathering cycles, the sample variations in grain size distributions are compared, and statistical tests are performed to show the statistical significance of the results. The results indicate that similar deterioration patterns occur on the samples with two weathering degrees under the same weathering tests. The increase in effective porosity surpasses that of the porosity only when the weathering effect is large enough. Furthermore, sandstone with a high degree of weathering might be more susceptible to changes in the internal pores due to its greater initial interconnectivity. In an open system, physical weathering (frost–thaw and dry–wet cycles) would cause the superficial grain size distributions of different rocks to become relatively uniform. Finally, when exposed to the same weathering process, the decreases in the overall mechanical strength in the two sandstones do not differ significantly, but the loss of superficial strength may be different. [ABSTRACT FROM AUTHOR]

In the northwest of China, many loess landslides have occurred without clear triggering factors (i.e., rainfall, earthquake, human activities, etc.). To better understand and analyze the hydro-mechanical properties of these slopes and then provide evidence for their stability analysis subjected to matric suction, it is essential to clarify the soil-water characteristic curve (SWCC). In this study, we conducted a set of experimental trials to examine the influences of initial dry density, water content upon the SWCCs of a loess soil taken from a loess landslide area, by using a conventional volumetric pressure plate extractor. Two common SWCC models have been investigated to evaluate which one is better for loess soil. The suction stress characteristic curves (SSCCs) were also estimated and analyzed. We found that behaviors of SWCCs would be different when the matric suction was greater than a certain value. The two SWCC equations have approximately the same performance in describing the SWCC. The rates of desorption decrease and residual water content increases with increasing the initial dry density, while the initial dry density has little, if any, influence on the air-entry value (AEV). The specimen compacted under higher initial water content would exhibit a higher AEV value and residual water content but lower rate of desorption as compared with the lower initial water content. The magnitude of suction stress had an approximately linear relationship with matric suction before the AEV value, the SSCC shapes will be markedly varied with the initial dry density and water content. [ABSTRACT FROM AUTHOR]

• The protective effects of sticky rice and lime composite are evaluated. • The relationship between macroscopic properties and microstructure is established. • The feasibility of protecting earthen sites with sticky rice and lime is discussed. Earthen sites have important historical, artistic, social, cultural, and scientific values. However, due to the extreme natural environment, they have suffered serious damage. The sticky rice and lime composite is one of the most important technological inventions in Chinese architectural history, which is an alternative material for the protection of earthen sites. In the past, the mechanical and microscopic properties of sticky rice and lime composite as binding material have been discussed. However, these properties are not sufficient to evaluate the feasibility of protecting earthen sites with sticky rice and lime composite. In this study, 25 groups of soil samples were prepared at five different lime contents (i.e. 0%, 3%, 6%, 9% and 12% by dry weight of sample) and five different sticky rice contents (i.e. 0.0%, 0.5%, 1.0%, 1.5% and 2.0% by dry weight of sample), and several important characteristics of the samples such as drying shrinkage, colour difference, surface hardness, unconfined compressive strength (UCS), and water vapour permeability are investigated comprehensively. Scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) were used to study the microstructure of samples. Then, the feasibility of protecting earthen sites with sticky rice and lime composite was systematically evaluated. The results indicate that the effectiveness of sticky rice and lime composite is better than that of their individual application. The optimal formula is 6% lime and 0.5% sticky rice for the protection of earthen sites when above indicators are compared. The surface fractal dimension builds bridges between microstructure and macroscopic properties of the soil with sticky rice and lime. Surface hardness and UCS are positively related to the surface fractal dimension, while water vapour permeability is negative related to the surface fractal dimension. This research further provides insights into the potential application of traditional Chinese inorganic–organic composite for protecting earthen sites in arid and semi-arid regions of northwest China. [ABSTRACT FROM AUTHOR]

• PVA-treated soil is confirmed to prevent water-salt capillary rise. • Effectiveness of 1.0% PVA-treated soil is best. • Interface effects are proposed to explain experimental phenomena. • Capillary rise of layered soil is described by modified Green-Ampt model. In the loess region of northwest China, the accumulation of soluble salt in the soil due to the capillary rise of water often damages earthen buildings. Thus, studies on the cutting off of the capillary-rise path are vital. As a hydrophobicity inducer, polyvinyl alcohol (PVA) solution with water as the solvent has the potential to function as a barrier. This study mainly aims to evaluate the feasibility of using PVA-treated soil as a waterproof layer to prevent water-salt capillary rise through soil column experiments, and the effects of the waterproof layer thickness, waterproof layer position, PVA content, ambient temperature, and type of salt solution on the capillary action. The results indicate that a 1.0% PVA-treated soil with extreme water repellency (i.e. dried at 20 °C) can perfectly prevent the water-salt from migrating to the top of the sample, regardless of the waterproof layer position, waterproof layer thickness, and type of soluble salt. For a 0.5% PVA-treated soil dried at 20 °C, the lower waterproof layer prevents the water-salt capillary rise, while the middle and upper layers exhibit less effectiveness. However, the PVA-treated soil that loses its hydrophobicity after a treatment at 100 °C cannot prevent the water-salt capillary rise, confirming that the prevention of capillary rise is due to the soil hydrophobicity. The waterproof layer thickness and type of soluble salt are less significant than the waterproof layer position, PVA content, and ambient temperature. This study proposes a modified Green-Ampt model to describe the capillary rise, and the hydraulic conductivity and pore size are obtained using the modified model. These parameters and the interface effect are used to explain the experimental results. Finally, the application of PVA-treated soil as a waterproof layer to inhibit water-salt capillary rise is illustrated. [ABSTRACT FROM AUTHOR]

Topographic attributes have been identified as the most important factor in controlling the initiation and distribution of shallow landslides triggered by rainfall. As a result, these landslides influence the evolution of local surface topography. In this research, an area of 2.6 km loess catchment in the Huachi County was selected as the study area locating in the Chinese Loess Plateau. The landslides inventory and landslide types were mapped using global position system (GPS) and field mapping. The landslide inventory shows that these shallow landslides involve different movement types including slide, creep and fall. Meanwhile, main topographic attributes were generated based on a high resolution digital terrain model (5 m × 5 m), including aspect, slope shape, elevation, slope angle and contributing area. These maps were overlaid with the spatial distributions of total landslides and each type of landslides in a geographic information system (GIS), respectively, to assess their spatial frequency distributions and relative failure potentials related to these selected topographic attributes. The spatial analysis results revealed that there is a close relation between the topographic attributes of the post-landsliding local surface and the types of landslide movement. Meanwhile, the types of landslide movement have some obvious differences in local topographic attributes, which can influence the relative failure potential of different types of landslides. These results have practical significance to mitigate natural hazard and understand geomorphologic process in thick loess area. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hoeffding Tree is a promising landslide susceptibility model based on ROC and AUC. • Bayes Network and Logistic Model Tree were applied for comparison. • Correlation analysis of conditioning factors was completed by Frequency Ratio. • Landslide susceptibility maps of Muchuan County and the county town were produced. Landslides, one of the most common hazards around the world, have brought about severe damage to life and property of human. To prevent and mitigate landslides, various models have been introduced to assess landslide susceptibility. In this paper, Hoeffding Tree (HT), a prevailing data stream mining algorithm, was employed to predict landslide susceptibility in Muchuan County, China for the first time. Meanwhile, Logistic Model Tree (LMT) and Bayes Network (BN) were applied to produce landslide susceptibility maps for comparison. The model performances were evaluated by Receiver Operating Characteristic (ROC) curves and areas under the curves (AUC). To obtain landslide inventory map, 279 landslides data was collected, and training and validation datasets were randomly divided with a proportion of 70% to 30%. Furthermore, twelve conditioning factors (altitude, slope angle, profile curvature, plan curvature, slope aspect, distance to roads, distance to rivers, TWI, NDVI, soil, land use and lithology) were selected to construct landslide susceptibility models. Moreover, correlations between conditioning factors and landslides were analyzed using Frequency Ratio (FR). The results showed landslides are prone to occur in areas where human activities concentrate, and all three models exhibited satisfying performances. Concretely, for training dataset, LMT model showed the highest AUC (0.854), followed by HT (0.726) and BN (0.709). However, for validation dataset, LMT and BN models generated similar AUC values (0.761 and 0.764 respectively), and the highest AUC value belonged to HT (0.802). The distributions of landslide susceptibility zones revealed that the interior of county town is mainly seated in low and very low susceptibility zones, whereas regions close to the border suffer high and very high landslide risk. The results acquired in this paper are significant to landslide prevention and urban planning in Muchuan, China. Additionally, this study proved that HT model is a promising classifier for landslide susceptibility modeling. [ABSTRACT FROM AUTHOR]

• Hydrophobicity arising from PVA changes erosion in different parts of earthen site. • Drying temperature control is a feasible method to eliminate the hydrophobicity. • Soil wettability is a crucial evaluation criterion for protection of earthen sites. • Drying temperature, surface roughness, PVA and water contents affect the wettability. Earthen sites in northwest China represent a precious cultural heritage; however, these sites have been seriously damaged by weathering. Chemical consolidation treatment is a widely accepted conservation method, and PVA solution with a high degree of alcoholysis has exhibited potential for improving the strength of soil. However, research on the influence of the PVA solution on the wettability of these earthen sites is rarely reported. Therefore, the aim of this study is to investigate the change in wettability of earthen sites protected with the PVA by laboratory experiments. First, the compressive strength and wettability of soil specimens are analysed with varying PVA content, water content, and drying temperature. The results indicate that the soil strength and hydrophobicity are highest when the PVA content in the soil is 1.0 wt%. The relationship between the soil hydrophobicity and water content follows a one-peak distribution, whereas the hydrophobicity decreases with increasing in drying temperature and is lost when the drying temperature is 80 °C or more. Second, factors influencing the wettability of the composite soil are discussed, and water vapour permeability of 1 cm thick composite soil is investigated in conjunction with exfoliation of surface crust. Finally, the feasibility of protecting different parts (i.e. the upper, middle, and lower parts) of earthen sites with PVA is briefly discussed, and it is emphasised that the wettability should be considered as crucial evaluation criterion for the protection of earthen sites. [ABSTRACT FROM AUTHOR]

• A SMOTE approach was proposed to handle imbalanced data of hazards levels. • SMOTE was integrated with Gaussian process for the prediction of hazards levels. • A real-world example is used to illustrate and validate the proposed approach. • Results from different data generation approaches are compared with that of SMOTE. • Results from different machine learning methods are compared with that of GP. Cultural soil heritages (CSHs) are artifacts with historical, artistic, and scientific significance; however, they are vulnerable to various hazards, such as weathering, fractures, hollowing, collapses, and gullies. This is especially true for those CSHs exposed to the outdoors. Due to the large number of CSHs sites within China, managing and protecting these heritages with the aid of detailed on-site investigations is time-consuming and expensive. Consequently, evaluating the spatial distribution and degree of hazards developed in all these heritages becomes impractical. To address this issue, this paper developed a Gaussian process classification (GPC) method to predict the spatial distribution of typical hazards (i.e., weathering, fractures, hollowing, collapses, and gullies) and the development level of each hazard from eight environmental factors (e.g., annual relative humidity and annual sunshine time) and a limited number of investigation data. As the number of investigation data for different levels of each hazard is usually imbalanced and sparse, this study proposed a synthetic minority oversampling technique (SMOTE) with GPC to form the SMOTE-GPC method. A real-world example is used to illustrate this approach. Results from real-world data demonstrated that the proposed method achieved an F 1 score, precision, recall, and Cohen's kappa with values greater than 0.93 in both the training and testing datasets, indicating its good performance. [ABSTRACT FROM AUTHOR]

• The morphology of differential weathering is digitized by 3D laser scanning. • The differential weathering features are characterized by the roughness indexes. • How spatial features of walls affect the differential weathering is discussed. • The classification of differential weathering degree is explored preliminarily. Earthen heritage sites have been undergoing lengthy surface weathering since they were built, which can pose a severe threat to the protection and utilization of these cultural treasures. Especially for differential weathering, one of the most common surface weathering patterns of earthen heritage sites in northwestern China, has not been well studied yet. Hence, in this paper, Suoyang Ancient City was selected as the study area, and six analysis domains (S1 to S6) exhibiting various differential weathering degrees were determined on wall faces and their morphological data were collected by a 3D laser scanner. Based on the point cloud data, the morphology of each domain was digitalized and reconstructed, and ten typical profiles were selected for roughness analysis. Concretely, for these profiles, six roughness parameters, including average asperity inclination (A i), mean curvature (R′da), textural slope parameter (Z 2), roughness coefficient (R p), self-affine fractal dimensions (A and D) and directional roughness metric (G (i)) were calculated to characterize their differential weathering features. The results show that the wall with a higher differential weathering degree has greater values of R p , G (i), A and D. It can also be found that different roughness indicators can reflect different wall surface morphological characteristics. In addition, the main driver of differential weathering developing is the prevailing sediment-laden wind, and the degree of differential weathering is also affected by the building techniques, wall endowment environment, wall orientation and morphology. Finally, according to the roughness values and wall surface morphology, the differential weathering degrees were classified into five grades (from level I to level V). In this case, the differential weathering degrees of S2 (level IV) and S5 (level IV) are the highest, followed by S3 (level III), S6 (level III), S1 (level II) and S4 (level II) respectively. Overall, the proposed approach based on 3D scanning and surface roughness is feasible to characterize the differential weathering degree, contributing to better prevention and mitigation of damage on earthen heritage sites. [ABSTRACT FROM AUTHOR]

• The development difference of scaling off on the sunward side and nightside of earthen sites was revealed. • The new indicators of salt migration gradient (SMG) and normalized shrinkage rate (NSR) were proposed. • The mechanism of salt difference and heterogeneous shrinkage on different building orientations were indicated. • Environmental monitoring was comprehensively analysed to explain the development difference of scaling off on different building orientations. Scaling off is one of the most representative deterioration types of earthen sites, severely causing their damage with a characteristic binary structure consisting of the crusted and loose layers. Exploring the development cause of scaling off is the key premise for targeted protection of earthen sites. Thus far, numerous researchers focused on environmental and rammed earth factors; however, the development difference of scaling off on different building orientations has not been studied. Therefore, this study aims to reveal the development difference of scaling off on the sunward side and nightside of earthen sites. In this study, 15 earthen sites situated in NW, China, are chosen and the scaling off is investigated in the field to collect characteristic values of the binary structure of scaling off on two sides of the wall. Subsequently, the previous built-up evaluation system is applied to calculate the development degree of scaling off to show its discrepancy rate (DR) on distinct building orientations. Additionally, the samples of rammed earth in different layers are collected and indoor geotechnical tests are performed to obtain the evaluation indicators. Combined with the binary structure and rammed earth properties, the salt differentiation and heterogeneous shrinkage of soils in different layers are quantificationally reflected. Finally, the temperature and humidity of three representative earthen sites are monitored for 24 h after rainfall. By analysing the environmental change, the greater amplitude of environmental change for the sunward side is found; this is an important driving force for salt migration, which leads to the difference in binary structures. This study reveals the development difference of scaling off on the sunward side and nightside from the quantitative perspective, which supplements current research contents on characteristics and mechanism of earthen sites deteriorations, beneficial to their further protection work. [Display omitted] [ABSTRACT FROM AUTHOR]

Coastal loess is a special loess deposit that is distributed around the Bohai Sea. The primary objective of this study was to investigate the physical index, mineralogical characteristics and collapse potential of coastal loess. The secondary objective was to survey the effect of fine silt particles (particle size 5–10 μm, 6.64–7.64φ) on the collapse process. We tested the specific gravity, moisture content, dry density, Atterberg limits, grain size distribution, mineralogy, and collapsibility characteristics in a laboratory; generated scanning electron microscopy (SEM) images; and performed Mercury intrusion porosometry (MIP) tests. The results of this investigation indicated that coastal loess has a moderately severe collapse potential. The collapsibility coefficient decreases with an increase in the initial water content; it initially increases and then decreases with an increase in vertical pressure. As revealed by the MIP test, the collapse produces a smaller porosity, and the middle pores are primarily responsible for the collapse. The relationship of the collapsibility coefficient and particles with a diameter < 10 μm reveals that fine silt particles (particle size 5–10 μm, 6.64–7.64φ) and clay particles (particle size < 5 μm, >7.64φ) have the same tendency in terms of their effect on collapse. These results and analyses are important to improve the engineering construction safety in coastal zone loess areas and achieve a better understanding of loess properties compared with loess from a typical loess-paleosol section. • Surveyed the particle and pore size distribution, Atterberg limits and mineralogical characteristics of Coastal loess. • Obtained the collapsibility of Coastal loess, and proposed the relationship between collapsibility coefficient and micro indexes based on the results of SEM and MIP tests. • Discussed the effect of fine silt particles (5-10 μm) on the collapse process. [ABSTRACT FROM AUTHOR]

Background: Intracranial atherosclerotic stenosis (ICAS) is one of the most common causes of stroke worldwide, and it is associated with a high risk of recurrent stroke with currently recommended treatments. We aimed to evaluate the effect of chronic remote ischaemic conditioning on prevention of ischaemic events in patients with symptomatic ICAS., Methods: The RICA trial is a multicentre, randomised, double-blind, sham-controlled trial at 84 stroke centres in China. Patients aged 40-80 years with ischaemic stroke or transient ischaemic attack attributable to angiographically verified 50-99% stenosis of a major intracranial artery were randomly assigned (1:1), via an interactive web-based system by computer-generated randomisation code, to either remote ischaemic conditioning or sham remote ischaemic conditioning once daily for 12 months and voluntarily thereafter. All investigators and patients were masked to treatment allocation. The primary efficacy endpoint was the time to first occurrence of non-fatal or fatal ischaemic stroke, with survival analysed by the Kaplan-Meier method. Primary and safety analyses were done in the intention-to-treat population. The RICA trial is registered with ClinicalTrials.gov, number NCT02534545., Findings: Between Oct 28, 2015, and Feb 28, 2019, 3033 patients were enrolled and randomly assigned to either remote ischaemic conditioning (n=1517; intervention group) or sham remote ischaemic conditioning (n=1516; sham group). Median follow-up was 3·5 years (IQR 2·7-4·4). A non-fatal or fatal ischaemic stroke occurred in 257 (16·9%) patients in the intervention group compared with 288 (19·0%) patients in sham group. There was no difference in the survival distribution for time to first occurrence of non-fatal or fatal ischaemic stroke (hazard ratio 0·87, 95% CI 0·74-1·03; p=0·12). In the intervention group, 79 (5·2%) patients died from any cause, and in the sham group, 84 (5·5%) patients died from any cause (hazard ratio 0·93, 95% CI 0·68-1·27; p=0·65). No intervention-related serious adverse events were observed., Interpretation: No evidence was found for a difference between remote ischaemic conditioning and sham remote ischaemic conditioning in lowering the risk of ischaemic stroke in patients with symptomatic ICAS. The benefit of remote ischaemic conditioning might have been diluted by poor compliance. Future studies of remote ischaemic conditioning in this population should address challenges in patients' compliance and assess longer term treatment., Funding: Ministry of Science and Technology China, Beijing Municipal Education Commission, Beijing Municipal Finance Bureau., Translation: For the Chinese translation of the abstract see Supplementary Materials section., Competing Interests: Declaration of interests CH has received speaker fees from Novo Nordisk and Pfizer. HS has received speaker fees from AstraZeneca, Pzier, Amgen, Boehringer Ingelheim, Novartis, and Sanofi. WZ has received speaker fees from Tasly Pharma. RM has received grants from Ministry of Science and Technology of the People's Republic of China. MIC has received grants from National Institute of Health (CAPTIVA, U01 NS117450–01A1). MIC has received honoraria for lectures on intracranial stenosis at Taiwan Neurological Conference, Taipei, April 1, 2021 (virtual presentation) and Grand Rounds at Harvard University, Cornell University, Dignity Health, and Northwell Health. DCH is on the Scientific Advisosry Board of Athersys, Inc and has received royalty payments. DSL has served as CEC member. DJH has received consultant fees from Faraday Pharmaceuticals Inc. and Boehringer Ingelheim International GmbH; honoraria from Servier; and research funding from Astra Zeneca and Merck Sharp & Dohme Corp. XZ has received speaker fees from AstraZeneca and Bayer. GL has received speaker fees from Techpool, CSPC, and Boehringer Ingelheim. WY has participated in speakers bureaus and received speaker fees from Bayer, Sanofi, Novartis, Xian Janssen, and Amgen. XJ has received grants from Beijing Municipal Education Commission and Beijing Municipal Finance Bureau. XJ has received speaker fees from AstraZeneca, Medtronic, and Sanofi. All other authors declare no competing interests., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Adipose tissue not only affects meat quality and animal productivity, but also participates in inflammation and immunity. Ningxiang pig is famous for their excellent meat quality, disease resistance and tolerance of roughage. It is not yet well known how proteins in adipose tissue is dynamically regulated during the growth of Ningxiang pig. This report studies the proteomic changes in subcutaneous adipose tissue in Ningxiang pigs to gain a better understanding of the molecular mechanism of fat development during the growth period. By TMT-labeled quantitative proteomic analysis of subcutaneous adipose tissue of 9 purebred Ningxiang pigs of different ages, we identified 2533 unique proteins and 716 differentially abundant proteins (DAPs), of which more than half of the DAPs were concentrated in the 90d-210d period. Retrograde endocannabinoid signaling was only significantly enriched in DAPs of N90d vs N30d, Alcoholism and Graft-versus-host disease were only significantly enriched in DAPs of N210d vs N90d. Proteins related to dilated cardiomyopathy was found to be an important pathway in fat development and lipid metabolism. A variety of novel DAPs involved in maintaining mitochondrial function and cell viability, such as NDUFS6, SDHB, COX5A, ATP5D and TNNT1, which play a role in controlling the prediction networks, may indirectly regulate the development and functional maintenance of adipocytes. SIGNIFICANCE: These age-dependent DAPs discovered in this study may help expand the understanding of the molecular mechanisms of the development, function maintenance and transformation of adipose tissue in Ningxiang pig for developing new strategies for improving meat quality and pig breeding in the future., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: There have been many studies on the relationship between circRNAs and fat deposition. Although the liver is a central organ for fat metabolism, there are few reports on the relationship between circRNAs in the liver and fat deposition., Methods: In this study, we systematically analyzed circular RNAs in the liver of Ningxiang pigs, at four time points after birth (30 days, 90 days, 150 days and 210 days)., Results: A total of 3705 circRNAs were coexpressed in four time periods were found, and KEGG analysis showed that the significantly upregulated pathways were mainly enriched in lipid metabolism and amino acid metabolism, while significantly downregulated pathways were mainly related to signal transduction, such as ECM-receptor interaction, MAPK signaling pathway, etc. Short time-series expression miner (STEM) analysis showed multiple model spectra that were significantly enriched over time in the liver. By constructing a competing endogenous RNA (ceRNA) regulatory network, 9187 pairs of networks related to the change in development time were screened., Conclusions: The expression profiles of circRNAs in Ningxiang pig liver were revealed at different development periods, and it was determined that there is differential coexpression. Through enrichment analysis of these circRNAs, it was revealed that host genes were involved in metabolism-related signaling pathways and fatty acid anabolism. Through STEM analysis, many circRNAs involved in fat metabolism, transport, and deposition pathways were screened, and the first circRNA-miRNA-mRNA regulation network map in Ningxiang pig liver was constructed. The highly expressed circRNAs related to fat deposition were verified and were consistent with RNA-Seq results.