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Summary: Major depressive disorder (MDD) is a prevalent mental disorder with serious impacts on life and health. Neuroimaging offers valuable diagnostic insights. However, traditional computer-aided diagnosis methods are limited by reliance on researchers’ experience. To address this, we proposed an evolutionary neural architecture search (M-ENAS) framework for automatically diagnosing MDD using multi-modal magnetic resonance imaging (MRI). M-ENAS determines the optimal weight and network architecture through a two-stage search method. Specifically, we designed a one-shot network architecture search (NAS) strategy to train supernet weights and a self-defined evolutionary search to optimize the network structure. Finally, M-ENAS was evaluated on two datasets, demonstrating that M-ENAS outperforms existing hand-designed methods. Additionally, our findings reveal that brain regions within the somatomotor network play important roles in the diagnosis of MDD, providing additional insight into the biological mechanisms underlying the disorder.

Reentry vehicles in near space used to suffer from communication blackout, which is led by the plasma sheath enveloping the whole reentry vehicle. Terahertz (THz) communication is believed to be a potential solution to mitigate the communication blackout effectively. Previous studies have investigated the attenuation characteristics of THz signals in plasma sheaths. However, the offset of THz signal transmission direction by the plasma sheath has rarely been a concern. In this study, the auto-evolution of the plasma sheath is taken into account. The consequent evolution of the refraction index distribution of the plasma sheath is investigated. It is found that the plasma sheath acts as a gradient index lens to the propagating THz signals. The lens structure keeps evolving due to the evolution of the plasma sheath itself. The main mechanism that dominates the evolution of the lens structure is the convection of electrons. By analyzing the offset of the transmission direction yielded by the lens structure, it is suggested that the onboard THz antenna could be installed close to the bottom of the vehicle in order to stabilize the transmission direction of THz signals in an evolving plasma sheath.

Background & Aims: A high human cytomegalovirus (HCMV) infection rate accompanied by an increased level of bile duct damage is observed in the perinatal period. The possible mechanism was investigated. Methods: A total of 1,120 HCMV-positive and 9,297 HCMV-negative children were recruited, and depending on age, their liver biochemistry profile was compared. Fetal and infant biliary epithelial cells (F-BECs and I-BECs, respectively) were infected with HCMV, and the differences in cells were revealed by proteomic analysis. Protein–protein interactions were examined by coimmunoprecipitation and mass spectrometry analyses. A murine cytomegalovirus (MCMV) infection model was established to assess treatment effects. Results: Perinatal HCMV infection significantly increased the level of bile duct damage. Neonatal BALB/c mice inoculated with MCMV showed obvious inflammation in the portal area with an abnormal bile duct structure. Proteomics analysis showed higher CD14 expression in F-BECs than in I-BECs. CD14 siRNA administration hindered HCMV infection, and CD14-knockout mice showed lower MCMV-induced bile duct damage. HCMV infection upregulated CD55 and poly ADP-ribose polymerase-1 (PARP-1) expression in F-BECs. Coimmunoprecipitation and mass spectrometry analyses revealed formation of the CD14–CD55 complex. siRNA-mediated inhibition of CD55 expression reduced sCD14-promoted HCMV replication in F-BECs. In MCMV-infected mice, anti-mouse CD14 antibody and PARP-1 inhibitor treatment diminished cell death, ameliorated bile duct damage, and reduced mortality. Conclusions: CD14 facilitates perinatal HCMV infection in BECs via CD55, and PARP-1-mediated cell death was detected in perinatal cytomegalovirus-infected BECs. These results provide new insight into the treatment of perinatal HCMV infection with bile duct damage. Impact and implications: Perinatal human cytomegalovirus (HCMV) infection is associated with bile duct damage, but the underlying mechanism is still unknown. We discovered that CD14 expression is increased in biliary epithelial cells during perinatal HCMV infection and facilitates viral entry through CD55. We also detected PARP-1-mediated cell death in perinatal HCMV-infected biliary epithelial cells. We showed that blocking CD14 or inhibiting PARP-1 reduced bile duct damage and mortality in a mouse model of murine cytomegalovirus infection. Our findings provide a new insight into therapeutic strategies for perinatal HCMV infection.

Depression ranks among the most prevalent mood-related psychiatric disorders. Existing clinical diagnostic approaches relying on scale interviews are susceptible to individual and environmental variations. In contrast, the integration of neuroimaging techniques and computer science has provided compelling evidence for the quantitative assessment of major depressive disorder (MDD). However, one of the major challenges in computer-aided diagnosis of MDD is to automatically and effectively mine the complementary cross-modal information from limited datasets. In this study, we proposed a few-shot learning framework that integrates multi-modal MRI data based on contrastive learning. In the upstream task, it is designed to extract knowledge from heterogeneous data. Subsequently, the downstream task is dedicated to transferring the acquired knowledge to the target dataset, where a hierarchical fusion paradigm is also designed to integrate features across inter- and intra-modalities. Lastly, the proposed model was evaluated on a set of multi-modal clinical data, achieving average scores of 73.52% and 73.09% for accuracy and AUC, respectively. Our findings also reveal that the brain regions within the default mode network and cerebellum play a crucial role in the diagnosis, which provides further direction in exploring reproducible biomarkers for MDD diagnosis.

The second Zagreb index and co-index are two important graph invariants. They are defined as [Formula: see text] and [Formula: see text], respectively, where [Formula: see text] is the complement of G and [Formula: see text] is the degree of a vertex u in G. In this paper, we study the upper and lower bounds for second Zagreb index and co-index of trees. Moreover, we determine the conditions that the upper and lower bounds for second Zagreb index and co-index of graphs are equal.

Background & Aims: Our previous study indicated that CD177+ neutrophil activation has a vital role in the pathogenesis of biliary atresia (BA), which is partially ameliorated by N-acetylcysteine (NAC) treatment. Here, we evaluated the clinical efficacy of NAC treatment and profiled liver-resident immune cells via single cell RNA-sequencing (scRNA-seq) analysis to provide a comprehensive immune landscape of NAC-derived immune regulation. Methods: A pilot clinical study was conducted to evaluate the potential effects of intravenous NAC treatment on infants with BA, and a 3-month follow-up was carried out to assess treatment efficacy. scRNA-seq analysis of liver CD45+ immune cells in the control (n = 4), BA (n = 6), and BA + NAC (n = 6) groups was performed and the effects on innate cells, including neutrophil and monocyte–macrophage subsets, and lymphoid cells were evaluated. Results: Intravenous NAC treatment demonstrated beneficial efficacy for infants with BA by improving bilirubin metabolism and bile acid flow. Two hepatic neutrophil subsets of innate cells were identified by scRNA-seq analysis. NAC treatment suppressed oxidative phosphorylation and reactive oxygen species production in immature neutrophils, which were transcriptionally and functionally similar to CD177+ neutrophils. We also observed the suppression of hepatic monocyte-mediated inflammation, decreased levels of oxidative phosphorylation, and M1 polarisation in Kupffer-like macrophages by NAC. In lymphoid cells, enhancement of humoral immune responses and attenuation of cellular immune responses were observed after NAC treatment. Moreover, cell–cell interaction analysis showed that innate/adaptive proinflammatory responses were downregulated by NAC. Conclusions: Our clinical and scRNA-seq data demonstrated that intravenous NAC treatment partially reversed liver immune dysfunction, alleviated the proinflammatory responses in BA by targeting innate cells, and exhibited beneficial clinical efficacy. Impact and implications: BA is a serious liver disease that affects newborns and has no effective drug treatment. In this study, scRNA-seq showed that NAC treatment can partially reverse the immune dysfunction of neutrophil extracellular trap-releasing CD177+ neutrophils and Kupffer cells, and lower the inflammatory responses of other innate immune cells in BA. In consequence, intravenous NAC treatment improved the clinical outcomes of patients with BA in term of bilirubin metabolism.

This paper proposes a dynamic phase comparison algorithm for planar direction finding on a high-speed moving satellite radio receiver, treating the moving antenna as equivalent to single-baseline array antennas. Based on a phase interferometer algorithm, this algorithm adjusts the baseline length according to the frequency measurement module and the satellite’s high-speed motion to avoid phase ambiguity indirectly. By integrating the traditional amplitude comparison algorithm based on orthogonal dipole antennas, a dynamic fusion direction-finding method is proposed. Simulations demonstrate that this approach method not only covers a broader range of direction finding but also achieves higher accuracy, providing valuable insights for acquiring three-dimensional plasmagrams with space-borne plasma imagers.

Communication blackouts have been a main threat to hypersonic vehicles for decades. The low frequency communication was considered a potential approach to mitigate the “blackout.” Nowadays, low frequency transmitters serving underwater communication have transmission power up to several megawatts. In other words, if low frequency communication signals could penetrate the plasma sheath, it would be a meaningful solution that using modern low frequency transmitters to give service to hypersonic vehicle communication, and the service area could be very large. Although the studies on blackouts using low frequency waves have lasted for many years, it still remains many unclear problems. The present study analyzes the characteristics of different frequency waves passing through a plasma sheath. The analysis revealed that the low frequency signals with high power could penetrate the plasma sheath and mitigate the blackout effectively. According to our simulation results, the transmission coefficient decreased with the flight speed and also increased with magnetic field intensity and the axial distance from the onboard antenna to the nose of the vehicle. Moreover, it is not sensitive to the frequency of signals. At last, two example models of using a ground low frequency station to communicate with the hypersonic vehicle were analyzed, which means that the low frequency communication can significantly be considered in the application of hypersonic vehicles in the near future.

The Yangtze River Economic Belt, as crucial component of China’s “T-shaped” strategy for territorial development and economic layout, has been challenged by the unbalanced spatial distribution of water resources, which has seriously affected high-quality development in harmony with the social economy and ecological environmental protection. In this study, we aim to enhance the conceptual definition of water resource spatial equilibrium. Additionally, we propose a water resource spatial equilibrium evaluation model based on a variable set and partial connection number. This model effectively addresses the limitations of traditional methods by incorporating fuzzy indices and dynamic information, which have previously been overlooked. The spatiotemporal characteristics and future evolutionary trend of water resource spatial equilibrium were analyzed in 11 provinces and 110 cities in the Yangtze River Economic Belt from 1999 to 2018. The results showed that the conceptual definition of water resource spatial equilibrium involves the water resource endowment, water resource development, water resource utilization, water resource supply and demand, water resource matching, and water resource protection. The water resource spatial equilibrium in the 11 provinces gradually improved following a temporal trend; in terms of the spatial trend, the south was better than the north and the west was better than the east. These provinces were sorted as follows: Yunnan > Sichuan > Zhejiang > Jiangxi > Hunan Province > Guizhou > Hubei > Chongqing > Anhui > Jiangsu > Shanghai. The evolutionary trend increased except in Yunnan. The water resource spatial equilibrium of the 110 cities showed that the spatial trends of the three major urban agglomerations were much better than in the other regions, and the temporal trend steadily improved. The 11 provinces and 110 cities could be divided into three and five categories, respectively, according to their spatiotemporal trends. City-scale research on water resource spatial equilibrium can effectively identify and optimize the control area compared with using a provincial scale. When the control targets were set to 20%, 40%, 60%, and 80%, the proportion of the administrative area based on the city scale decreased by 1.20%, 4.99%, 10.52%, and 19.05%, respectively.

Drought forecasting, which can enable contingency actions to be implemented in advance of a drought, plays a significant role in reducing the risks and impacts of drought. In this study, a simulation framework of the occurrence probability of drought events based on a nested copula function and Gibbs sampling is proposed to effectively compensate for the high-dimensional problems and lack of initial data in traditional methods. Precipitation data of 718 meteorological stations from 1961 to 2018 in China was analyzed. The results showed that the occurrence location of drought events was mainly concentrated from 35° to 42° north latitude and 105° to 120° east longitude, with the occurrence time mainly concentrated from September to November. The Archimedean-copula function, constructed based on latitude, longitude, and occurrence time, could precisely determine the spatiotemporal joint probability distribution of drought events (RMSE: 0.01). The optimal time-varying nested Archimedean-copula functions were obtained from February to May (spring), June to September (summer) and October to January (autumn and winter). Compared with the nested Archimedean-copula function, the accuracy of Gibbs sampling and simulation based on the time-varying nested Archimedean-copula function was increased by 84.05% latitude and 69.76% longitude. The results provide an effective means for scientific drought forecasting, and water resource management departments can take preventive measures at an early stage. HIGHLIGHTS This is the first to attempt to propose the quantitative framework of drought forecast based on run analysis theory, Archimedean-copula function, and Gibbs sampling.; The optimal time-varying nested Archimedean-copula functions are constructed.; Drought prediction accuracy is improved.;

Since the industrial revolution, excess inputs of nitrogen (N) and phosphorus (P) from human activities have been the main threat of deterioration to water environmental quality. In this study, to understand the variation characteristics, evolutionary pattern, composition structure, and main influencing factors on net anthropogenic nitrogen inputs (NANI) and net anthropogenic phosphorus inputs (NAPI) in the Yangtze River Economic Belt, 20 years of data from 1999 to 2018 at the general, provincial and city scales were analyzed. The results showed that NANI and NAPI in the Yangtze River Economic Belt increased and then decreased from 1999 to 2007 and from 2008 to 2018, with average values of 7189.26 kg N km−2 yr−1 and 2169.31 kg P·km−2 yr−1. Fertilizer application constituted the largest source of contributions to NANI and NAPI, with average contribution rates of 66.31 % and 68.20 %. The spatial pattern of NANI and NAPI exhibited a decreasing trend from east to west and from north to south. Western Jiangsu, eastern Anhui, central Hubei, and western Sichuan were high-risk areas. The contribution rates of human activity factors were ranked as economic factors > land-use factors > social factors, and changes in economic factors contributed the most to changes in NANI and NAPI, with averages of 70.50 % and 70.10 %. The Yangtze River Economic Belt has crossed the Environmental Kuznets Curve (EKC) inflection point for the N/P input load and has entered the coordinated development stage of economic growth and environmental improvement. The city scale can effectively identify and optimize the control area compared with the provincial scale, and the proportions of the administrative areas for NANI and NAPI at different targets decreased by 4.11 % (5.20 %), 7.52 % (11.95 %), and 9.79 % (17.29 %), respectively.

Abstract In the recent couple of decades, some multifunctional spaceborne active radars had been launched. Those radars used to be broadband radars using dipole transmitting antennas. The odd‐order resonant frequency of the antenna does not completely cover the operating frequency of the entire radar, so this may cause the antenna's radiation efficiency to deteriorate. The typical method to solve this problem was to design an impedance matching network system for broadband antennas to achieve a good voltage standing wave ratio and transmit power gain. In this paper, a new optimized real‐frequency method was designed, and a 0.4‐meter dipole antenna was tested before and after impedance matching. The measured results showed that the impedance matching network obtained by the optimized real‐frequency method proposed in this paper can improve the antenna radiation efficiency, and can effectively reduce the standing wave ratio to avoid damage to the transmitter caused by high echo power.

Aiming at solving the issue of blurred images and difficult recognition of digital meters encountered by inspection robots in the inspection process, this paper proposes a deep-learning-based method for blurred image restoration and LED digital identification. Firstly, fast Fourier transform (FFT) is used to perform blur detection on the acquired images. Then, the blurred images are recovered using spatial-attention-improved adversarial neural networks. Finally, the digital meter region is extracted using the polygon-YOLOv5 model and corrected via perspective transformation. The digits in the image are extracted using the YOLOv5s model, and then recognized by the CRNN for digit recognition. It is experimentally verified that the improved adversarial neural network in this paper achieves 26.562 in the PSNR metric and 0.861 in the SSIM metric. The missing rate of the digital meter reading method proposed in the paper is only 1% and the accuracy rate is 98%. The method proposed in this paper effectively overcomes the image blurring problem caused by the detection robot during the detection process. This method solves the problems of inaccurate positioning and low digital recognition accuracy of LED digital meters in complex and changeable environments, and provides a new method for reading digital meters.

Water resources are the foundation of economic development, social progress and ecological security, and water shortage is the primary problem facing China. Water quotas have great practical significance for the resolution of water shortages to achieve sustainable use of water resources and sustainable development of the national economy. In this study, to analyse the problems and countermeasures of the water quota system in China, the water quota system progress domestically and abroad, the water quota problem in China, and the countermeasures for the water quota problem are summarized. The data validity test, spatial correlation test and consistency test are used to test the rationality of water use quota. And the specific countermeasures are presented: improving the water quota system, defining its concept, and revising its scheme, etc. This study provides the support to standardize water quotas and implement the effective water conservation policies of China. HIGHLIGHTS Introduces a method that uses data validity test, spatial correlation test and consistency test of the water quota reasonableness to test the rationality of water quota.; Presents several specific recommendations: improving the water quota system, defining its concept and revising its scheme; Provides the support to standardize water quotas and implement the effective water conservation policies.;

Nanoparticles (NPs) have been widely used as target delivery vehicles for therapeutic goods; however, compared with inorganic and organic nanomaterials, protein nanomaterials have better biocompatibility and can self-assemble into highly ordered cage-like structures, which are more favorable for applications in targeted drug delivery. In this review, we concentrate on the typical protein cage nanoparticles drugs encapsulation processes, such as drug fusion expression, diffusion, electrostatic contact, covalent binding, and protein cage disassembly/recombination. The usage of protein cage nanoparticles in biomedicine is also briefly discussed. These materials can be utilized to transport small molecules, peptides, siRNA, and other medications for anti-tumor, contrast, etc.

The Yangtze River Economic Belt, which is an important development axis of China’s “T-shaped” strategy, has been challenged by water resource utilization and water environment protection due to the rapid development of the social economy. In this study, to understand the variation characteristics, competition and cooperation relationship, and optimal stable point of synergetic development capability of the “water resource–water environment–socioeconomic development” coupling system, 20 years of data, from 1999 to 2018, at the general, provincial, and city scales were analyzed. The results showed that the synergetic development capability of the Yangtze River Economic Belt in 2011 was a mutation point; it fluctuated slightly before 2011 and steadily rose after 2011, with an average value of 2.46. The three subsystems were all in an evolutionary state, and the evolution speed was sorted by socioeconomic development > water resources > water environment. The water resource subsystem and water environment subsystem had a win–win relationship, and the other subsystems had a lose–lose relationship. Moreover, the synergetic evolution stable point of the Yangtze River Economic Belt was (0.8625,0.8236,1.5841). From the spatial trend, the synergetic development capability in the west was better than in the east and the capability in the south was better than in the north. The spatial agglomeration and spatial heterogeneity in 110 cities were more obvious than those of 11 provinces. From the temporal trend, the synergetic development capability gradually improved. Additionally, the synergetic development capability and its rank obeyed Zipf’s rank-size rule, and the degree of deviation gradually reduced. Furthermore, the Yangtze River Economic Belt can be divided into nine secondary urban agglomerations, and the western, central, and eastern regions paid more attention to socioeconomic development, water environment improvement, and water resource protection, respectively. The “siphon effect” in the central cities was greater than the “radiation effect”. This study provided a method for effectively evaluating the synergetic development characteristics and is of great significance to the protection, development, and utilization of water resources.

To solve the problem of inflexibility of offline hand–eye calibration in “eye-in-hand” modes, an online hand–eye calibration method based on the ChArUco board is proposed in this paper. Firstly, a hand–eye calibration model based on the ChArUco board is established, by analyzing the mathematical model of hand–eye calibration, and the image features of the ChArUco board. According to the advantages of the ChArUco board, with both the checkerboard and the ArUco marker, an online hand–eye calibration algorithm based on the ChArUco board is designed. Then, the online hand–eye calibration algorithm, based on the ChArUco board, is used to realize the dynamic adjustment of the hand–eye position relationship. Finally, the hand–eye calibration experiment is carried out to verify the accuracy of the hand–eye calibration based on the ChArUco board. The robustness and accuracy of the proposed method are verified by online hand–eye calibration experiments. The experimental results show that the accuracy of the online hand–eye calibration method proposed in this paper is between 0.4 mm and 0.6 mm, which is almost the same as the offline hand–eye calibration accuracy. The method in this paper utilizes the advantages of the ChArUco board to realize online hand–eye calibration, which improves the flexibility and robustness of hand–eye calibration.

Bridges have been widely used in highway and railway engineering, especially in mountain areas. The differential settlement between bridge abutment and approach embankment is one of the most challenging problems, and it will result in “bumps” to affect the driving safety and comfortableness at the end of a bridge. The geogrid-reinforced and pile-supported embankment (GRPS embankment) is proposed to mitigate the differential settlement at the bridge approach. In this paper, the model tests and numerical studies are carried out to study the long-term performance of the GRPS embankment considering the consolidation of subsoil. Firstly, a series of model tests are conducted to evaluate the long-term performance of the GRPS embankment using a specially designed model box. Then, the numerical model is constructed using the finite element software MIDAS, and the numerical model is verified from the model test results. Finally, a parametric study is conducted to investigate the influences of pile net spacing, pile modulus, and filling modulus.

Communication blackout is always a serious threat to the flight tasks of modern hypersonic vehicles moving in near space. EHF communication is considered as a potential solution to the blackout problem. Nevertheless, EHF waves suffer from severe attenuation in hypersonic plasma sheaths. An external magnetic field could mitigate EHF wave attenuation in hypersonic plasma sheaths. Dipole magnetic fields, generated by coils, are feasible in realistic scenarios. In the present study, a model for EHF wave propagation in hypersonic plasma sheaths magnetized by dipole magnetic fields that are generated with coils is developed. The dissipation caused by the inhomogeneity of dipole magnetic fields and the magnetic field component of electromagnetic waves are compared with the dissipation yielded by the collision between electrons and neutral particles. The results show that collision is still the main dissipation mechanic for EHF waves. The study also found that, in the blunt-coned plasma sheath, the mitigation effect of a dipole magnetic field is weaker than that of a uniform magnetic field. The mechanics which yield the difference is analyzed. In addition, the relation between the characteristics of EHF waves and the coil parameters is investigated. Suggestions for the coil parameters and the operation frequencies of the EHF communication systems are made based on the investigation.

Communication blackout caused by the plasma sheath surrounding hypersonic vehicles is a serious threat to the safety of hypersonic vehicles. Terahertz (THz) communication is considered to be a potential solution to the blackout problem. However, hypersonic plasma sheaths can affect not only electromagnetic wave propagation, but also the radiation performance of onboard antennae. Therefore, it is necessary to investigate the radiation performance of THz antennae in hypersonic plasma sheaths. In the present study, the impact of vehicle shapes (blunt-coned and sharp-coned vehicles) on plasma sheaths was investigated numerically. The antenna involved in the present study was a 0.14 THz array antenna. The antenna performance was compared with the aspects of mainlobe gain, mainlobe direction, and mainlobe width. The present study shows that both sharp-coned and blunt-coned plasma sheaths are inhomogeneous. Nevertheless, their structures are obviously different. Such differences yield different antenna performance in sharp-coned and blunt-coned plasma sheaths. Compared with sharp-coned plasma sheaths, blunt-coned plasma sheaths can refract antenna radiation direction, which can result in worsened communication quality in the expected direction. In addition, the phenomena are discussed in detail. Suggestions of vehicle shape design to guarantee communication quality in hypersonic flight missions are proposed.

The impact of global climate change on agroecosystems is growing, affecting reference crop evapotranspiration (ET0) and subsequent agricultural water management. In this study, the climate factors temporal trends, the spatiotemporal variation, and the climate driving factors of ET0 at different time scales were evaluated across the Northern Yellow River Irrigation Area (NYR), Central Arid Zone (CAZ), and Southern Mountain Area (SMA) of Ningxia based on 20 climatic stations’ daily data from 1957 to 2018. The results showed that the Tmean (daily mean air temperature), Tmax (daily maximum air temperature), and Tmin (daily minimum air temperature) all had increased significantly over the past 62 years, whilst RH (relative humidity), U2 (wind speed at 2 m height), and SD (sunshine duration) had significantly decreasing trends across all climatic zones. At monthly scale, the ET0 was mainly concentrated from April to September. And at annual and seasonal scales, the overall increasing trends were more pronounced in NX, NYR, and SMA, while CAZ was the opposite. For the spatial distribution, ET0 presented a trend of rising first and then falling at all time scales. The abrupt change point for climatic factors and ET0 series was obtained at approximately 1990 across all climatic zones, and the ET0 had a long period of 25a and a short period of 10a at annual scale, while it was 15a and 5a at seasonal scale. RH and Tmax were the most sensitive climatic factors at the annual and seasonal scales, while the largest contribution rates were Tmax and SD. This study not only is important for the understanding of ET0 changes but also provides the preliminary and elementary reference for agriculture water management in Ningxia.

This paper presents an experimental study on the anisotropic shear strength behavior of soil–geogrid interfaces. A new type of interface shear test device was developed, and a series of soil–geogrid interface shear tests were conducted for three different biaxial geogrids and three different triaxial geogrids under the shear directions of 0°, 45° and 90°. Clean fine sand, coarse sand, and gravel were selected as the testing materials to investigate the influence of particle size. The experimental results for the interface shear strength behavior, and the influences of shear direction and particle size are presented and discussed. The results indicate that the interface shear strength under the same normal stress varies with shear direction for all the biaxial and triaxial geogrids investigated, which shows anisotropic shear strength behavior of soil–geogrid interfaces. The soil–biaxial geogrid interfaces show stronger anisotropy than that of the soil–triaxial geogrid interfaces under different shear directions. Particle size has a great influence on the anisotropy shear strength behavior of soil–geogrid interfaces.

The rapid process of urbanization has led to water pollution, reduction of space areas and channel deposition. However, current river protection and management levels are not suitable for city development level and human demand. Therefore, these problems have not yet been solved. China is still in an era of rapid urbanization, which means that the influence of urbanization in rivers will increase in the future—and the task of river protection and management will be more arduous. In order to meet the challenges and opportunities brought by urbanization and promote the sustainable use and management of river, this study puts forward relevant suggestions on river protection and management, such as river management mechanisms, economic incentive instruments, technical support, transformation of development concepts, improving laws, regulations and policies and stimulating public participation.

Drought is a water deficit state caused by large-scale climate change that cannot be avoided by a water resource management system. Water scarcity refers to the unsustainable utilization of water resources over a long time, which is the result of water management policies. However, water deficits caused by drought and water scarcity often occur simultaneously and are indistinguishable. This study proposes a model-based simulation framework that can quantitatively distinguish natural factors (drought) from human factors (water scarcity) in a hydrological system. The simulation was applied to the Zhangweinan Canal Basin, based on the runoff sequences from 1950 to 2004. The results show that the runoff curve number, soil depth, soil available water, soil evaporation compensation coefficient, base runoff α coefficient and the maximum canopy interception have the highest sensitivity to runoff, and that the calibrated and validated SWAT model can effectively simulate the runoff process in the Zhangweinan Canal Basin and similar areas. Abrupt changes in human activities in 1975 and water scarcity led to the disappearance of the summer peak runoff period in both wet and dry years. Human factors are the main reason for the change in the hydrological system in the study area; the runoff loss caused by human factors is four times that caused by natural factors according to the proposed variable threshold. This study proposes a model-based simulation framework that can help water resource managers to distinguish the effects of drought and water scarcity in water-stressed areas and adjust management accordingly.

The security of food-energy-water (FEW) systems is an issue of global concern, especially in mega-urban regions (MURs) with high-density populations, industries and carbon emissions. To better understand the hidden links between urbanization and FEW systems, the pressure on FEW systems was quantified in a typical rapidly urbanizing region—the Bohai MUR. The correlations between urbanization indicators and the pressure on FEW systems were analyzed and the mechanism of the impact of urbanization on FEW systems was further investigated. The results showed that approximately 23% of cropland was lost, 61% of which was lost via conversion to construction land and urban areas expanded by 132.2% in the Bohai MUR during 1980–2015. The pressure on FEW systems showed an upward trend, with the stress index of the pressure on FEW systems (FEW_SI) ranging from 80.49% to 134.82%. The dominant pressure consisting of that has converted from water system pressure to energy system pressure since 2004. The FEW_SI in the Bohai MUR was enhanced with cropland loss and increases in urbanization indicators. Additionally, land use, populations, incomes, policies and innovation are the main ways that urbanization affects FEW systems in MURs. This study enhances our understanding of the variation in pressure on FEW systems in MURs and the effects of urbanization on FEW systems, which will help stakeholders to enhance the resilience of FEW systems and promote sustainable regional development.

From the microperspective, this paper presents a model based on a new type of noncontinuous theoretical mechanical method, molecular dynamics (MD), to simulate the typical soil granular flow. The Hertzian friction formula and viscous damping force are introduced in the MD governing equations to model the granular flow. To show the validity of the proposed approach, a benchmark problem of 2D viscous material flow is simulated. The calculated final flow runout distance of the viscous material agrees well with the result of constrained interpolated profile (CIP) method as reported in the literature. Numerical modeling of the propagation of the collapse of three-dimensional axisymmetric sand columns is performed by the application of MD models. Comparison of the MD computational runout distance and the obtained distance by experiment shows a high degree of similarity. This indicates that the proposed MD model can accurately represent the evolution of the granular flow. The model developed may thus find applications in various problems involving dense granular flow and large deformations, such as landslides and debris flow. It provides a means for predicting fluidization characteristics of soil large deformation flow disasters and for identification and design of appropriate protective measures.