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The importance order of causes of a railway signaling system hazard is important for the arrangement of control measures for eliminating or controlling the system hazard. In order to obtain a reasonable importance order, a novel importance order analysis method based on complex networks is proposed in this article. In this article, to characterize the causes from a topological perspective, a comprehensive topology characteristic is proposed. It is built on the top of three typical topology characteristics with the weighted Euclidean distance. Then, an influence coefficient matrix is proposed to measure the causal influence between causes. Based on the proposed topology characteristic and matrix, an algorithm is designed to identify the importance order of causes. To verify the effectiveness of the proposed method, a case study on a Chinese high-speed railway signaling system hazard is performed. The results show that the proposed method is feasible for the arrangement of control measures to eliminate or control system hazards and performs better than the traditional complex network-based methods in terms of avoiding conflicting and rough results.

The magnesium (Mg) and silicon (Si) co-doped LiNi0.5Mn1.5O4 sample has been obtained by sol-gel method. The effects of co-doping with magnesium and silicon ions on the phase structure, morphology and electrochemistry characteristics of LiNi0.5Mn1.5O4 are investigated by a series of physico-chemical characterizations. XRD results demonstrate that the magnesium and silicon ions successfully enter into the spinel structure and make the lattice parameter slightly increased. Moreover, the magnesium and silicon ions co-doped sample presents superior cycling stability. When cycled at 0.5 C, this sample still delivers 121 mAh g−1 after 100 cycles with outstanding retention of 98.86%, while the undoped LiNi0.5Mn1.5O4 sample only exhibits 104.5 mAh g−1 after 100 cycles with low retention of 79.17%. In addition, the Mg2+ and Si4+ co-doped sample shows outstanding rate capability and low charge transfer resistance.

Sialic acid content generally affects many biochemical properties of therapeutic glycoproteins. More specific properties, such as charge distribution, circulating half-life and bioactivity, are directly impacted by sialic acid content. Undesirable loss of protein sialylation is commonly observed in CHO bioprocesses, and sialic acid degradation is one of the root causes. In this work, sialic acid degradation by extracellular sialidase was investigated in an Fc-fusion protein production bioprocess. First, cell-free incubation with the cell culture supernatant (CCS) collected at the end of culture revealed a 12.46% drop in sialic acid content by sialidase after 6 days of incubation, while other monosaccharides on the glycans remained stable. Then, potential factors that could affect the action of sialidase were studied, and a pH of over 7.05 was found to have a strong inhibitory effect on the degradation of sialic acid in the CCS. The results were further validated in bioreactors with different pH controls to demonstrate that a minimization of sialic acid loss could be achieved by controlling pH at higher values. Our work provides a simple and effective way to alleviate the decrease in sialic acid content and improves the understanding of the relationship between process control and product sialylation in CHO bioprocesses.

Xenotransplantation is an attractive solution to the problem of allograft shortage. However, transplants across discordant species barriers are subject to vigorous immunologic and pathobiologic hurdles, some of which might be overcome with the induction of immunologic tolerance. Several strategies have been designed to induce tolerance to a xenograft at both the central (including induction of mixed chimerism and thymic transplantation) and peripheral (including adoptive transfer of regulatory cells and blocking T cell costimulation) levels. Currently, xenograft tolerance has been well-established in rodent models, but these protocols have not yet achieved similar success in nonhuman primates. This review will discuss the major barriers that impede the establishment of immunological tolerance across xenogeneic barriers and the potential solution to these challenges, and provide a perspective on the future of the development of novel tolerance-inducing strategies.

The differences of molecular characteristic of humic acid (HA) under long-term application of chemical fertilizer and manure for 34 years were determined by 13 C cross polarization magic angle spinning nuclear magnetic resonance ( 13 C CPMAS NMR) spectroscopy in order to investigate the carbon (C) sequestration in soils. The results showed that the relative content of alkyl C increased in manure treatments, compared to control and chemical fertilizer treatments. There were positive correlations between alkyl C and hydrogen to carbon (H/C) ratio (R 2 = 0.84, P 2 = 0.57, P 2 = 0.55, P 2 = 0.76, P = 0.01), H/C ratio and aromaticity (R 2 = 0.37, P = 0.04), aromaticity and amounts of HA (R 2 = 0.71, P 2 = 0.65, P 2 ) n /Long-chain (CH 2 ) n ratio increased for 0.03–0.37 and 0.03–0.18 in chemical fertilizer treatments and manure treatments, separately. These findings suggest that application of manure favours alkyl C sequestration in HA and tends to be more closely linked to amorphous C than crystalline C, while incorporates less short-chain (CH 2 ) n , compared to chemical fertilizer treatments. Moreover, the E4/E6 ratio of HA increased with more alkyl C.

The Hydraulic turbine efficiency is traditionally calculated by the pressure drop between the inlet and outlet. But this method cannot determine the detailed energy loss distributions along the flow passage. Entropy production theory can predict and exhibit the irreversible energy loss distribution intuitively. An advanced entropy production diagnostic model (EPDM) with phase transition (EPDMS) is introduced in this study to evaluate the irreversible energy loss in cavitating flows. The EPDM method is based on homogeneous equilibrium model (HEM) without interface slip velocity while EPDMS is based on two fluid model (TFM) with the consideration of slip velocity and interface forces. At operating point guide vane opening (GVO) 20.07, the relative error of EPDM for efficiency calculation is 6.87% and the relative error of EPDM is 3.05%. In EPDMS, the interaction between cavitation and entropy production rate (EPR) is defined and interface EPR (IntE) has a considerable proportion of total EPR in EPDMS. With the HEM method, the underprediction of the turbulent eddy viscosity results in the underestimation of irreversible energy loss. In essence, the intensive mass transfer process in cavitation flow induces the generation of IntE and corresponding irreversible energy loss directly.

We report that the efficiency of the spin-Hall spin–orbit torque (SOT) in perpendicularly magnetized Pt/Co/MgO films can be engineered by introducing ruthenium (Ru) impurities into the bulk of the Co layer. As the concentration of the Ru impurities increases, the effective field of the damping-like SOT is increased by a factor of 2.3, leading to SOT efficiency per unit current density enhancing from 0.069 to 0.155. However, the Ru incorporation shows less impact on the field-like SOT efficiency. First-principles calculations reveal that the Ru incorporation can significantly increase the density of states of the majority spin at the Fermi level but has less influence on the minority spin case. We suspect that such an electronic-structure modulation may reduce the scattering of the spin-Hall spin currents flowing across the Co-Ru layer, resulting in SOT efficiency enhancement. The SOT enhancement by Ru incorporation is also observed in Ta/CoFeB/MgO films, indicating that modulating the spin scattering inside ferromagnets with judiciously selected impurities is a promising strategy to construct low-power-dissipation SOT spintronic devices.

Li-S batteries have been regarded as one promising candidate for next-generation energy storage systems, however, their practical implementations are severely hindered by the intractable polysulfides shuttle (PSS) effect and retarded conversion kinetics. Herein, a flexible electrode consisting of Co9S8 nanocrystals and CNTs encapsulated inside porous N-doped carbon nanofibers (NCF) (CNT@NC/Co9S8) was developed by electrospinning followed by in-situ sulfurization. The carbon nanofibers and embedded CNTs build a highly conductive network, while the Co9S8 and N dopant provide more polar sites for LiPSs confinement. This self-supported flexible electrode with a sulfur loading of 12.5 mg cm−2 exhibits a high initial discharge capacity (1207.7 mAh g−1 at 0.1C), excellent rate capability (831.2 mAh g−1 at 4.0C) and cycling stability (765.5 mAh g−1 with a capacity retention of 78.1% after 1000 cycles at 2.0C). Moreover, when the sulfur loading increases to 20 and 30 mg cm−2, high capacities of 869.2 and 706.6 mAh g−1can still be obtained at 0.1C after 100 cycles, respectively. Theoretical analysis suggests that the sulfur cathode built on CNT@NC/Co9S8 is electrocatalytically active towards LiPSs redox with enhanced conversion dynamics, thus mitigating the detrimental PSS effect.

A large amount of excavated soil (ES) is generated in subway construction. Improper stacking will bring a serious threat to the environment and human safety. To recycle this excavated soil, the method of the cold bonding granulation technique was adopted to prepare core–shell structured ceramsite, which had an ES coating of expanded perlite particles. The effects of the cement content and the curing method on the pore structure, water absorption, and mechanical properties of the ceramsite were analyzed. Scanning electron microscopy (SEM) was employed to investigate the microstructure of the ceramsite. In addition, X-ray micro-computed tomography (XCT) was used to explore the internal core–shell structure of the ceramsite. The results revealed that ceramsite with a water absorption of 26%–55% and a single particle crushing strength of 7.48–22.12 N could be achieved. This core–shell structured ceramsite could potentially be used as water-retaining materials to be applied in landscaping and agriculture.

Sulfamethazine (SMZ) as a broad antibiotic is widely used in livestock and poultry. However, the abuse of SMZ in livestock feed can lead to SMZ residues in food and the resistance of bacteria to drugs. Thus, a method for the detection of SMZ in food is urgently needed. In this study, quantum dot (QD) nanobeads (QBs) were synthesized by encapsulating CdSe/ZnS QDs using a microemulsion technique. The prepared QBs as signal probes were applied in lateral flow immunoassay (LFIA) for the detection of SMZ in chicken and milk. Our proposed method had limits of detection of 0.1138–0.0955 ng/mL and corresponding linear ranges of 0.2–12.5, 0.1–15 ng/mL in chicken and milk samples, respectively. The recovery of LFIA for the detection of SMZ was 80.9–109.4% and 84–101.6% in chicken and milk samples, respectively. Overall, the developed QBs-LFIA had high reliability and excellent potential for rapid and sensitive screening of SMZ in food.

In this study, the durability of glass fiber-reinforced polymer (GFRP) bars in alkaline environments was studied. The GFRP bars were immersed in distilled water and alkaline solutions of various pH values at temperatures of 21 °C, 40 °C, and 60 °C. The water absorption and interlaminar shear strength of the GFRP bars were measured concerning conditioning time. The equilibrium water absorption of the GFRP bars in an alkaline solution of pH 13.0 was one order of magnitude higher than that of GFRP bars in distilled water and an alkaline solution of pH 10.0. Compared with samples conditioned in distilled water or the alkaline solution of pH 10.0, those aged in the alkaline solution of pH 13.0 showed a greater reduction in interlaminar shear strength. This reduction increased with increasing environmental temperature and conditioning time. Scanning electron microscopy images showed that the deterioration of GFRP bars aged in the alkaline solution of pH 13.0 was mainly caused by interfacial debonding between glass fibers and resin matrices. Equations were proposed for predicting the long-term interlaminar shear strength of GFRP bars as a function of water absorption and adopted to predict the interlaminar shear strength of GFRP bars in fields. The prediction results roughly match the measurement results.

The Intelligent Railway Driving Assistance System (IRDAS) is a novel kind of onboard system that relies on its own situational awareness function to ensure the safety and efficiency of train driving. In such systems, the use of situational awareness brings about a new fault-free safety problem, i.e., the safety of the intended functionality (SOTIF). It is essential to analyze the SOTIF-related hazardous factors for ensuring a safe train operation. In this paper, a hazard analysis approach is proposed to capture and evaluate SOTIF-related hazardous factors of IRDAS. This approach consists of an extended STPA-based hazardous factor identification part and a complex network-based hazardous factor evaluation part. In the first part, an extended control structure of STPA is designed for the modeling of the situational awareness process, followed by a new classification of SOTIF-related causal scenarios to assist the identification of causal scenarios. In the second part, a modeling method for heterogeneous complex networks and some customized topological indexes are proposed to evaluate the hazardous factors identified in the STPA causal analysis. The outcomes of the approach can help develop targeted hazard control strategies. The proposed approach has been applied to a new IRDAS operating in Tsuen Wan Line of Hong Kong MTR. The result shows that the approach is effective for the analysis of hazardous factors and is helpful for the formulation of hazard control strategies.

Shiga toxin-producing Escherichia coli (STEC) is known as a kind of foodborne pathogens that can produce Shiga toxin type1, type 2, or both, encoded by stx1 and stx2 genes, respectively. Rapid and accurate detection of STEC and stx1/stx2 subtyping assay in food and environment is essential for foodborne outbreak investigation. In this study, a method for the accurate and rapid subtyping of STEC single colony using asymmetric polymerase chain reaction (asPCR) combined with lateral flow immunoassay (LFIA) was established. AsPCR was conducted using biotinylated stx1 and digoxin-labeled stx2 primers to obtain several single stranded DNA amplicons labeled with biotin or/and digoxin. Subsequently, these amplicons were tagged with specific probes labeled with carboxylate-modified red polystyrene microspheres using sequential hybridization. Finally, STEC with different Shiga toxin gene types could be distinguished depending on the appearance of different test lines on an LFIA strip. Thus, the STEC single colony could be identified and subtyped accurately and conveniently using this method. This method showed high specificity. Twenty-four strains of STEC in milk were detected and subtyped using our method, which combines asPCR with LFIA.

Li-S batteries have been recognized as one of the most promising candidates for next-generation energy storage systems, however, their practically commercialized applications are severely hindered by the shuttle effect of lithium polysulfides (LiPSS), retarded conversion kinetics and the growth of lithium dendrites. Herein, a vertically growing layered NiFe-LDH derived Ni4N-Fe2N heterostructure cross-like nanoarrays on a carbon cloth (CC) (denoted as CC@Ni4N-Fe2N@C) was constructed by a pot of hydrothermal method followed by the subsequent carbon coating and nitridation processes to synchronously tackle the above challenges related to Li-S batteries. This heterostructure presents good sulfiphilic and lithiophilic properties and can be directly used as the host materials both for S and Li. As-expected, this heterostructure exhibits the significantly improved discharge specific capacity, rate performance and cycle stability compared with the single-metal nitrides (CC@Ni4N@C and CC@Fe2N@C). The study of the symmetric cells certifies that this heterostructure can expose the abundant lithiophilic active sites to achieve the homogeneous Li deposition and effectively suppress the growth of Li dendrites.

A series of single-crystal polyhedra spinel LiAlxMn2-xO4 (x = 0, 0.05, 0.10, 0.15 and 0.20) cathode materials have been rapidly prepared by a solution combustion technique using HNO3 solution as an auxiliary oxidant. The crystal structure and phase identification of as-prepared samples were characterized through X-ray diffraction (XRD), which shows that all samples present the characteristic diffraction peaks of spinel LiMn2O4. The morphology and particle size of as-prepared samples were observed by field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM), which indicate that all samples have single-crystal polyhedra morphology and good crystallinity. The cycling performances of as-prepared samples were evaluated by galvanostatic charge/discharge cycling performance tests, which demonstrate that LiAl0.10Mn1.90O4 exhibits the optimal cycling and rate properties. It delivers a capacity retention rate of 60.7% after 2000 cycles with an initial discharge specific capacity of 99.5 mAh g−1 at 10 C (1 C = 148 mAh g−1) and 25 °C, while the capacity retention rate of pristine LiMn2O4 is only 9.6% with an initial discharge specific capacity of 81 mAh g−1 at the same conditions. The Al-doped samples show better elevated temperature cycling stability than pristine LiMn2O4. LiAl0.10Mn1.90O4 sample shows a capacity retention rate of 81.5% with a discharge specific capacity of 91.3 mAh g−1 after 500 cycles at 1 C and 55 °C, which is much superior compared with the capacity retention rate of 18.5% for pristine LiMn2O4. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) tests certify that LiAl0.10Mn1.90O4 presents the better electrode reversibility, more rapidly charge-transfer and Li+ diffusion kinetics processes.

It is a challenge to properly generalize hydrological characteristics under the great heterogeneity of climate and landscape conditions across space because the linkage and interaction among hydro-climate–landscape factors are complicate and ambiguous at regional scale. In this study, multivariate statistical analyses including clustering, correlation and regression analysis were combined with Budyko and L’vovich frameworks to regionalize runoff characteristics over Jinghe River Basin of northwest China. For all 23 sub-basins, the hydrologic factors were quantified using the metrics of mean annual values and intra-annual variability of runoff. The climatic factors are determined from precipitation, potential evapotranspiration and aridity index, and the landscape factors were extracted from topography, soils and vegetation of the sub-basins. Results illustrated that the 23 sub-basins can be classified into two groups, the dry Loess Plateau (LP) and the wet Mountain Region (MR) in the study basin. The runoff metrics of sub-basins in each group present similarity in spatial distribution, intra-annual variations and the dominant influence factors of climate and landscape. But such runoff metrics characteristics and their co-dependence are significantly different between the two clustered sub-basins. Higher runoff and gentler hydrographs were observed in the MR in response to wetter and greater intra-annual variability in climate and greater spatial variability in landscape, whereas lower runoff and sharper hydrograph were seen in response to drier and greater intra-annual variability in climate, and less spatial variability in landscape in the LP. The runoff spatial distribution is more sensitive to climate spatial variation than to landscape in LP as opposed to the MR. Among the landscape factors, forest distribution is the dominant control on the spatial runoff characteristics in LP whereas topography is principal factor in MR. Our results highlight that current measures of reforestation plus marked change in climate in the Loess Plateau could lead to significant change in streamflow.

We used hierarchical linear regression analysis to test the relationship between negative feedback and employee job performance, and explored the moderating role of the Big Five personality traits in this relationship. Participants were 357 supervisor–subordinate dyads in China; subordinates responded to negative feedback and Big Five personality traits measures, and direct supervisors rated their employees' job performance. Results showed that negative feedback was negatively related to employee job performance, and that the Big Five personality traits moderated this relationship. Specifically, the strength of the negative relationship between negative feedback and job performance was reduced as extraversion, openness to experience, agreeableness, emotional stability, and conscientiousness increased. Implications for management and theory are discussed.

Catchment classification strategies based on easily available physical characteristics are important for extrapolating hydrologic model parameters and improving hydrologic predictions in ungauged catchments. In this study, we conduct an experiment of catchment classification and explore the feasibility of characterizing hydrologically similar catchments using certain physical characteristics in upstream regions of the Huai River Basin. The similarity metrics of hydrologic response factors (high flow, low flow and average annual runoff) and physical factors (topography, shape, soil and vegetation) are fed into the K-means algorithm for catchment classification. All the catchments are classified into two classes regardless of the types of metrics used. By comparing the overlap coefficient (η) and Rand index (RI) between any two classification results, we found that the topography classification displays the highest concordance with the high flow classification (η = 79.2% and RI = 0.66) among all metrics. Including more metrics would not produce consistently better classification results. The optimal combination of metrics, with η = 87.5%, is the high flow metrics (Q10%, SFH and MAX90) with the topography metrics (AS and HI). The results indicate that the physical metrics adopted for hydrologic classification should be determined carefully in terms of specific hydrologic characteristics.

This study was run to investigate effects of dietary glycinin on the growth performance, digestion, intestinal morphology and bacterial community of juvenile turbot (Scophthalmus maximus L.). Graded levels (0%, 3%, 6% and 12%) of purified glycinin were added to the basal diet to formulate four experimental diets containing 0%, 2.18%, 4.17% and 8.31% immunologically active glycinin, respectively. Triplicate groups of 30 fish were fed to apparent satiation twice daily for 12 weeks. Dietary inclusion of glycinin did not affect feed intake, feed efficiency ratio or weight gain of turbot, however, fish fed 12% glycinin showed a significant decrease in the apparent digestibility of dry matter and protein, as well as the whole-body lipid content. Meanwhile, slightly increased infiltration of mixed leukocytes in the lamina propria was observed in turbot fed 12% glycinin, so was specific IgM against glycinin in the serum. Sequencing of bacterial 16s rRNA V4 region showed that Proteobacteria (90.64%), Bacteroidetes (6.01%) and Firmicutes (1.73%) were the dominant bacteria in the intestine of turbot. Dietary inclusion of glycinin had no significant effect on the overall structure of bacterial community but dramatically reduced the relative abundance of the Vibrio genus, one of the core microbes, in a dose-independent manner. Our results suggest that turbot can tolerate a relatively high level of immunologically active glycinin (8.31%) in the diet without showing notable impairments of growth performance and gut function.

A (Li, Al)-co-doped spinel Li(Li 0.05 Al 0.05 Mn 1.90 )O 4 (LAMO) cathode material has been rapidly prepared by a solution combustion method. The structure of as-prepared samples was characterized by X-ray diffraction (XRD), which shows that (Li, Al)-co-doping does not change the intrinsic spinel structure of LiMn 2 O 4 . The morphology and particle size of the as-prepared samples were analyzed by field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM), which indicate that the LAMO has high crystallinity, regular truncated octahedran morphology and uniform particle size distribution. The X-ray photoelectron spectrometer (XPS) measurement shows that (Li, Al)-co-doping increases the average valence of Mn. The cycle performance was evaluated by galvanostatic charge-discharge cycling test. The results show that LAMO maintains a high discharge specific capacity of 98.0 mAh g − 1 with a capacity retention of 82.4% after 1000 cycles at 5C (1C = 148 mAh g − 1 ) compared with that of 60.7 mAh g − 1 with a capacity retention of 60.4% for the pristine LiMn 2 O 4 (LMO). Furthermore, LAMO exhibits obvious improvement of elevated-temperature cyclic performance, resulting in a superior capacity retention of 73.9% after 400 cycles at 1C at 55 °C with an initial discharge specific capacity of 107.2 mAh g − 1 , which is much higher than that of 14.6% for the pristine LMO. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) studies certify that (Li, Al)-co-doping improves the reversibility and enhances kinetics process of electrode.

The eddy covariance technique was used to measure the energy fluxes of a paddy field under water-saving irrigation in the South China Plain for the stage of rice growth in 2013. This study analyzed the energy balance components and evaluated the energy balance closure. The study also discussed the response of surface energy balance to the change in soil heat storage between the heat flux plates buried at a specific depth and the surface, and the phase shift correction of energy balance components, by using three different statistical methods, namely ordinary least squares (OLS), energy balance ratio (EBR), and energy balance residual (D). The results showed that the OLS slope increased by an average of 8.8%, and the mean daily EBR increased by 5.0% after considering the change in soil heat storage. The range of half-hourly D over a four-month period decreased from –129 - 260 W m −2 to –102 - 194 W m −2 , and the absolute value of D decreased by 9.9% on the average. Considering the phase correction, the increase in OLS regression coefficients with an average of 11.3% and the decrease in half-hourly D, ranging from –61 to 176 W m −2 , both indicated that phase shift correction improved the surface energy balance closure at the half-hourly scale, specifically in the period from sunrise to noon, but had no use in the daily scale. Thus, the two correction methods are useful in improving the degree of energy balance closure shown in different temporal scales with proper evaluation index. Moreover, further research should be given with more attention for other correction aspects.

With the development of urbanization, there is a decreasing tendency for people contact with natural greenness. Whether maternal exposure to greenness has an impact on pregnancy complications and pregnancy outcomes remains to be confirmed.To estimate the association and dose-response relationship between residential greenness and pregnancy outcomes.PubMed, Embase, Ovid, Scopus and Web of Science from inception to 1st December 2019 were searched.The summary regression coefficient (β) and odds ratio (OR) with corresponding 95% confidence interval (95%CI) were calculated. The linear dose-response relationship between greenness and adverse pregnancy outcomes was also investigated.Overall, 36 studies with a total of 11,983,089 participants were included. Birth weight was significantly higher in highest level of greenness exposure group compared to lowest level group (e.g. β:20.22, 95%CI:13.50-26.93 at 100 m buffer). The odds of low birth weight (LBW) decreased in the highest level of group compared to lowest level group (e.g. OR:0.86, 95%CI:0.75-0.99 at 100 m buffer). The odds of small for gestational age (SGA) also decreased in the highest group (OR:0.93, 95%CI:0.88-1.00 at 100 m buffer). In addition, maternal exposure to greenness was associated with increased head circumference and decreased mental disorders. The dose-response models showed a 2% decrease risk of LBW per 0.1 normalized difference vegetation index (NDVI) increase within 300 m buffer (OR:0.98, 95%CI:0.97-0.99, P 0.001) and a 1% decrease risk of SGA per 0.1 NDVI increase within 300 m buffer (OR:0.99, 95%CI:0.98-1.00, P = 0.037). No significant associations were found on preterm birth, gestational age, gestational diabetes mellitus, gestational hypertension or preeclampsia.This review confirms an inverse association between residential greenness and adverse pregnancy outcomes. Findings of our study provide evidences for pregnant women to increase greenness exposure.

This paper investigates the physical processes involved in the water filling and air expelling process of a pipe with multiple air valves under water slow filling condition, and develops a fully coupledwater&ndash, air two-phase stratified numerical model for simulating the process. In this model, the Saint-Venant equations and the Vertical Average Navier&ndash, Stokes equations (VANS) are respectively applied to describe the water and air in pipe, and the air valve model is introduced into the VANS equations of air as the source term. The finite-volume method and implicit dual time-stepping method (IDTS) with two-order accuracy are simultaneously used to solve this numerical model to realize the full coupling between water and air movement. Then, the model is validated by using the experimental data of the pressure evolution in pipe and the air velocity evolution of air valves, which respectively characterize the water filling and air expelling process. The results show that the model performs well in capturing the physical processes, and a reasonable agreement is obtained between numerical and experimental results. This agreement demonstrates that the proposed model in this paper offers a practical method for simulating water filling and air expelling process in a pipe with multiple air valves under water slow filling condition.

The early age volume deformation is the main course for the cracking of high-performance concrete (HPC). Hence, the shrinkage behavior and the restrained stress development of HPC under different restraints and curing conditions were experimentally studied in this paper. The method to separate the stress components in the total restraint stress was proposed. The total restrained stress was separated into autogenous shrinkage stress, drying shrinkage stress and thermal stress. The results showed that the developments of the free shrinkage (autogenous shrinkage and drying shrinkage) and the restrained stress were accelerated when the drying began, but the age when the drying began did not significantly influence the long-term shrinkage and restrained stress of HPC, the autogenous shrinkage stress continuously contributed to the development of the total restrained stress in HPC, the drying shrinkage stress developed very rapidly soon after the drying began, and the thermal stress was generated when the temperature dropped. The thermal stress was predominant at the early age, but the contributions of the three stresses to the total restrained stress were almost the same at the age of 56 d in this study.

Saturated hydraulic conductivity (K), drainable porosity (f), and effective aquifer thickness (D) are essential hydrogeological parameters for hydrologic modelling and predicting. Streamflow recession analysis using analytical solutions of Boussinesq equation can yield estimated values for two of these three hydrogeological parameters when one is known a priori. In this study, we improved the inverse method for parameters estimation by combining the modified Kozeny–Carman equation with analytical solutions of Boussinesq equation to express the three hydrogeological parameters (K, f, and D) in relation to catchment characteristics and recession constants in a sloping aquifer. Here, the three parameters can be estimated simultaneously from streamflow recession analysis. Results of the estimated parameters are compared with the field measurements and the soil-texture based estimations in four small experimental catchments. It shows that our estimated values of these catchment-scale parameters can represent equivalent values in the measured aquifer profiles/sites. In hilly areas, the slope aquifer takes a vital effect on the estimates of K and f. Neglecting the sloping effect can lead to overestimation of K and underestimation of f in 1 ~ 2 orders of magnitude in the study catchments. However, even in the hilly catchments, the estimated aquifer thickness D is much greater than that from measurements on hillslopes while it approaches riparian thickness, indicating that the riparian zone takes a vital role on flow recession and the parameter estimations.

In most Asian high mountain areas, ground-based observations of precipitation are sparse. It is urgent to assess and apply satellite precipitation products (SPPs). In recent years, relatively dense rain gauges have been established in five tributaries in Lhasa. Therefore, based on high-density rain gauges, two SPPs (GPM IMERG V05B, TRMM 3B42V7) were evaluated at the grid, region, and time scales with different statistical indices in the five tributaries. Besides, the dependence of SPPs performances on the precipitation intensities, elevation, and slope was investigated. The results indicate that: (1) both 3B42V7 and IMERG showed similarly low correlation with rain gauges at daily scale and high correlation at monthly scale, but 3B42V7 tended to suffer from systematic overestimation of monthly precipitation; (2) IMERG product outperformed 3B42V7 except for obvious overestimation of trace precipitation (0.1~1 mm day−1) and underestimation of torrential precipitation (>50 mm day−1); (3) the precipitation over the five tributaries showed significant spatial variability with difference of characteristic values (e.g., average daily precipitation) more than 20% in some IMERG grids and most 3B42V7 grids; (4) elevation had an obvious effect on the accuracy of 3B42V7 and IMERG, and the accuracy of the two SPPs decreased significantly with the increase of elevation.

In epidemiology, gerontology, human development and the social sciences, age-period-cohort (APC) models are used to study the variability in trajectories of change over time. A well-known issue exists in simultaneously identifying age, period and birth cohort effects, namely that the three characteristics comprise a perfectly collinear system. That is, since age = period-cohort, only two of these effects are estimable at a time. In this paper, we introduce an alternative framework for considering effects relating to age, period and birth cohort. In particular, instead of directly modeling age in the presence of period and cohort effects, we propose a risk modeling approach to characterize age-related risk (i.e., a hybrid of multiple biological and sociological influences to evaluate phenomena associated with growing older). The properties of this approach, termed risk-period-cohort (RPC), are described in this paper and studied by simulations. We show that, except for pathological circumstances where risk is uniquely determined by age, using such risk indices obviates the problem of collinearity. We also show that the size of the chronological age effect in the risk prediction model associates with the correlation between a risk index and chronological age and that the RPC approach can satisfactorily recover cohort and period effects in most cases. We illustrate the advantages of RPC compared to traditional APC analysis on 27496 individuals from NHANES survey data (2005-2016) to study the longitudinal variability in depression screening over time. Our RPC method has broad implications for examining processes of change over time in longitudinal studies.

The exploitation of groundwater resources is of great importance and has become crucial in the last few decades, especially in arid regions, where surface water resources are scarce and unreliable. The Hexi Corridor (HC) is one of the most agriculturally rich and densely populated areas of arid northwestern China. Increasing demand for water, due to rapid population growth, oasis expansion and urbanization, has increased groundwater use, resulting in wide-scale depletion in this region. Sustainable management of aquifers in the HC requires accurate estimates of the current situation of groundwater resource sustainability. In this work, groundwater storage anomaly (∆GWS) were estimated using the Gravity Recovery and Climate Experiment (GRACE) satellite data, the Global Land Data Assimilation System (GLDAS) data and the water-table fluctuation (WTF) method based on in-situ groundwater level data. Combined with the groundwater sustainability index (SIGWS), groundwater sustainability in the HC was then evaluated. Potential factors that could affect regional groundwater sustainability were analyzed by including and testing climate and socio-economic variables during the period of 1981 to 2016. We found that (1) groundwater in the HC has experienced a general deterioration (except for a sudden and sharp increase observed around 2002) in both storage and sustainability, from ∆GWS = 16.79 cm/year and SIGWS = 0.46 (1985–1990) to ∆GWS = −28.96 cm/year and SIGWS = 0.008 (2007–2016); (2) the lowest value of groundwater sustainability in the HC appeared in the central and eastern regions (SIGWS = 0); (3) human activity was confirmed to be the dominant factor driving the processes of deterioration in groundwater sustainability in the HC, and during the research period, it is striking that relatively limited “positive” effects of the water management project were detected on the regional groundwater resource; this result indicates that damaged groundwater sustainability cannot be easily reversed unless a long-term management policy is implemented. This study also proves that GRACE gravity satellite data has great application potential in groundwater sustainability evaluation in arid regions, especially in developing countries where in-situ data are scarce, and highlights the importance of joint management of surface water and groundwater, in groundwater sustainability management.

Climate warming is changing streamflow regimes and groundwater storage in cold alpine regions. In this study, a headwater catchment named Yangbajain in the Lhasa River Basin is adopted as the study area for quantifying streamflow changes and active groundwater storage in response to climate warming. The changes in streamflow regimes and climate factors are evaluated based on hydro-meteorological observations from 1979 to 2013. The results show that annual streamflow increases significantly at a rate of about 12.30 mm/10a during this period. Through baseflow recession analysis, we also find that the estimated groundwater storage that is comparable with the GRACE data increases significantly at the rates of about 19.32 mm/10a during these years. The rising of air temperature is the main factor for the increase in streamflow and groundwater storage, which has led to a loss of over 25 % of the total glacier volume for half century in this catchment. Parallel comparisons with other sub-basins in the Lhasa River Basin reveal that the increased streamflow at the Yangbajain station is mainly fed by the accelerated glacier retreat rather than frozen ground degradation. However, the increase of active storage capacity is caused by frozen ground degradation, which can accommodate the increasing meltwater in the valley. The huge gap between the melt-derived runoff and the increased water volume in groundwater storage and streamflow suggests that more than 60 % of the total ablation of glaciers should be discharged downstream through deep fault. This study provides a perspective to clarify the impact of glacial retreat and frozen ground degradation on hydrological processes, which fundamentally affects the water supply and the mechanisms of streamflow generation and change.

Cavitation and system instability are the most common problems occurring in hydraulic power systems, especially operated under part-load conditions. Previous research show that when the hydraulic turbine operates apart from designed conditions, such as part-load conditions, a helical vortex rope occurs from the runner exit, and usually generates severe pressure oscillations. Cavitation usually appears and turns the rope to become a two-phase cavitation rope. The occurrence of cavitation rope is believed to be the main reason of the severe pressure oscillations. Based on a new multiphase flow simulation method re-developed in ANSYS CFX, this paper did the runner modification by using grooves and made the investigation of pressure fluctuation alleviation in a hydraulic turbine at different cavitation numbers. The behavior of cavitation rope and the pressure fluctuations induced by cavitation under typical part load conditions with modified runner were analyzed in present research. The results show that besides the pressure fluctuation induced by the rope rotating, cavitation induced a new pressure fluctuation with a lower frequency. For the embedded analysis the results show that the modified runner can decrease the vortex rope eccentricity and increase the vortex core pressure and finally alleviate the two types of pressure fluctuations. Also, the turbine efficiency has a little rise when equipped with the modified runner.

Graphene and graphene oxide (GO) sheets have great potential to improve the properties of traditional cement-based building materials. This research studied the effects of graphene and GO s...

An accurate assessment of soil water budget components (SWBCs) is necessary for improving irrigation strategies in any water-limited environment. However, quantitative information of SWBCs is usually challenging to obtain, because, since the hydrological process of farmland is principally driven by irrigation (I), drainage (D), and evapotranspiration (ET) in desert oasis settings, none of the drivers can be easily measured under actual conditions. Soil moisture is a variable that integrates the water balance components of land surface hydrology, and the evolution of soil moisture is assumed to contain the memory of antecedent hydrologic fluxes, and thus can be used to determine SWBCs from a hydrologic balance. A database of soil moisture measurements from six experimental plots with different treatments (NT1 to NT6) in the middle Heihe River Basin of China was used to test the potential of a soil moisture database in estimating the SWBCs. We first compared the hydrophysical properties of the soils in these plots, such as vertical saturated hydraulic conductivity (Ks) and soil water retention features, for supporting the SWBC estimations. Then we determined evapotranspiration and other SWBCs through a soil-moisture data-based method that combined both the soil water balance method and the inverse Richards equation. To test the accuracy of our estimation, we used both the indirect methods (such as power consumption of the pumping irrigation well), plenty of published SWBCs values at nearby sites, and the water balance equation technique to verify the estimated SWBCs values, all of which showed a good reliability of our estimation. Finally, the uncertainties of the proposed methods were analyzed to evaluate the systematic error of the SWBC estimation and the restriction for its application. The results showed significant variances among the film-mulched plots (NT2–6) in both the cumulative irrigation volumes (between 652.1 mm at NT3 and 867.3 mm at NT6) and deep drainages (between 170.7 mm at NT3 and 364.7 mm at NT6). Moreover, the unmulched plot (NT1) had remarkably higher values in both cumulative irrigation volumes (1186.5 mm) and deep drainages (651.8 mm) compared with the mulched plots. Obvious correlation existed between the volume of irrigation and that of drained water. However, the ET demands for all the plots behaved pretty much the same, with the cumulative ET values ranging between 489.1 and 561.9 mm for the different treatments in 2016, suggesting that the superfluous irrigation amounts had limited influence on the accumulated ET throughout the growing season because of the poor water-holding capacity of the sandy soil. This work confirmed that relatively reasonable estimations of the SWBCs in coarse-textured sandy soils can be derived by using soil moisture measurements; the proposed methods provided a reliable solution during the entire growing season and showed a great potential for identifying appropriate irrigation amounts and frequencies, and thus a move toward sustainable water resources management, even under traditional surface irrigation conditions.

Information processing in the mammalian brain relies on a careful regulation of the membrane potential dynamics of its constituent neurons, which propagates across the neuronal tissue via electrical signalling. We recently reported the existence of electrical signalling in a much simpler organism, the bacterium Bacillus subtilis. In dense bacterial communities known as biofilms, nutrient-deprived B. subtilis cells in the interior of the colony use electrical communication to transmit stress signals to the periphery, which interfere with the growth of peripheral cells and reduce nutrient consumption, thereby relieving stress from the interior. Here, we explicitly address the interplay between metabolism and electrophysiology in bacterial biofilms, by introducing a spatially extended mathematical model that combines the metabolic and electrical components of the phenomenon in a discretized reaction-diffusion scheme. The model is experimentally validated by environmental and genetic perturbations, and confirms that metabolic stress is transmitted through the bacterial population via a potassium wave. Interestingly, this behaviour is reminiscent of cortical spreading depression in the brain, characterized by a wave of electrical activity mediated by potassium diffusion that has been linked to various neurological disorders, calling for future studies on the evolutionary link between the two phenomena. This article is part of the theme issue 'Liquid brains, solid brains: How distributed cognitive architectures process information'. This work was supported by the Spanish Ministry of Economy and Competitiveness and FEDER (project FIS2015-66503-C3-1-P), and by the Generalitat de Catalunya (project 2017 SGR 1054). R.M.C. acknowledges financial support from La Caixa foundation. J.G.O. acknowledges support from the ICREA Academia programme and from the “Mar ́ıa de Maeztu” Programme for Units of Excellence in R&D (Spanish Ministry of Economy and Competitiveness, MDM-2014-0370). G.M.S. acknowledges support for this research from the San Diego Center for Systems Biology (NIH grant P50 GM085764), the National Institute of General Medical Sciences (grant R01 GM121888), the Defense Advanced Research Projects Agency (grant HR0011-16-2-0035), and the Howard Hughes Medical Institute-Simons Foundation Faculty Scholars program. A.P. is supported by a Simons Foundation Fellowship of the Helen Hay Whitney Foundation and a Career Award at the Scientific Interface from the Burroughs Wellcome Fund.

Search strategy (DOCX): a text listing the search strategies of CENTRAL, MEDLINE, EMBASE, PsycINFO, CNKI, VIP, SinoMed, and Wanfang Databases. (DOCX 24 kb)

Effect estimates summary (DOCX): a table listing the effect estimates of all comparisons and all subgroup-analyses. (DOCX 31 kb)

Sulfamethazine (SMZ), widely used for disease prevention of bees, is harmful to consumers when excess SMZ residues are present in honey. In this study, a novel competitive lateral flow immunoassay (LFIA) was established by using aggregation-induced emission fluorescent microsphere (AIEFM) as label for the detection of SMZ. Results indicated that the limit of detection (LOD) for the developed competitive AIEFM-LFIA in honey was 0.028 ng/mL, and the corresponding linear range was 0.05−5 ng/mL. Recovery experiments showed that the average recovery range was 75.6–95.1% with coefficient variations of 5.7–12.9% in honey. The developed competitive AIEFM-LFIA was compatible with HPLC-MS/MS in detecting SMZ in 15 real samples from honey. In general, the proposed AIEFM-LFIA is well suited for the competitive format and has great potential for the detection of other small targets with single antigenic site in practical application.

Tensile creep is an important parameter to evaluate cracking probability of high-strength concrete (HSC) structure, and the mineral admixtures have great effect on it. In this paper, the early-age tensile basic creep behaviors of HSC containing fly ash (FA) and blast furnace slag (BS) were investigated by experiments, and the influences of loading age and stress level (stress-strength ratio of initial loading) were evaluated. The results showed that FA promoted the early-age tensile basic creep while BS inhibited the early-age tensile creep. Moreover, the influence of loading age on early-age tensile basic creep of HSC was more significant, and the affected ages’ duration was longer than that of plain concrete. The early-age tensile basic creep of HSC containing admixtures also showed linear creep characteristic after a certain age as HSC without admixtures, and the linear characteristic was more obvious at a later loading age. The tensile basic creep velocity of HSC containing FA was the highest, while HSC containing BS exhibited the lowest velocity. The influence of admixtures on velocities of tensile basic creep was gradually attenuated with the age growth in holding period.

Supplementary text, table and figures

Content of the twelve Chinese herbal preparations (DOCX): a table listing the content of the twelve Chinese herbal preparations. (DOCX 60 kb)

Microplastic (MP) is an emerging environmental pollutant and exposure to MPs has been associated with numerous adverse health outcomes in both wild and laboratory animals. The toxicity of MPs depends on concentration, exposure time, chemical composition and size distribution, but the impacts of particle size remain inconclusive yet. In this study, adult marine medaka (Oryzias melastigma) were exposed to different size of polystyrene MPs (PS-MPs) with concentration of 10 mg/L for 60 days and the growth performance, lipid metabolism, immune parameters and gut microbiome were determined. Results indicated that particle size is a dominant factor causing lipid metabolism disorders and hepatic toxicity in PS-MPs-exposed fish. The bodyweight, adipocyte size and hepatic lipid contents were significantly increased in 200 μm PS-MPs-exposed fish, while 2 and 10 μm PS-MPs-exposed fish exhibited liver injury principally manifested as the presence of little fibrosis and inflammation. Given that larger particles could not enter the circulatory system, the impacts of PS-MPs on intestinal microbial biota homeostasis were further investigated. The results not only showed the characterization of gut microbial communities in Oryzias melastigma, but also indicated that microbial diversity and composition were altered in gut of fish exposed to PS-MPs, in particular 200 μm PS-MPs. The differentially abundant bacterial taxa in PS-MPs-exposed fish mainly belonged to the phylum Verrucomicrobia, Firmicutes and Fusobacteria. And furthermore, increased abundance of Verrucomicrobia and Firmicutes/Bacteroidetes ratio and decreased Fusobacteria were correlated with the increased bodyweight. Intestinal microbiome should play a critical role in regulating host lipid metabolism in fish exposed to lager size of PS-MPs.

In aquaculture, the real-time detection and monitoring of feed pellet consumption is an important basis for formulating scientific feeding strategies that can effectively reduce feed waste and water pollution, which is a win-win scenario in terms of economic and ecological benefits. However, low-quality underwater images and extremely small targets present great challenges to feed pellet detection. To overcome these challenges, this paper proposes an uneaten feed pellet detection model using an improved You Only Look Once (YOLO)-V4 network for aquaculture. The specific implementation methods are as follows: (1) The feature map responsible for large-scale information in the original YOLO-V4 network is replaced by a finer-grained YOLO feature map by modifying the connection mode of the feature pyramid network (FPN) + path aggregation network (PANet). (2) The residual connection mode in CSPDarknets is modified via a DenseNet, which further improves the feature reuse and the network performance. (3) Finally, a de-redundancy operation is carried out to reduce the complexity of the YOLO-V4 network while ensuring the detection accuracy. Experimental results in a real fish farm showed that the detection accuracy is better than that of the original YOLO-V4 network, and the average precision is improved from 65.40% to 92.61% (when the intersection over union is 0.5), for an increase of 27.21%. Additionally, the amount of computation is reduced by approximately 30%. Therefore, the improved YOLO-V4 network can effectively detect underwater feed pellets and is applicable in actual aquaculture environments.

The construction of a virtual interactive model based on VR technology breaks through the single mode of traditional virtual reality helmets, through optical attitude sensing, immersive cave virtual reality, multi-person network collaboration, 9D interactive media applications, and mobile terminal interaction. The organic integration and application of technologies have improved the user’s interactive experience, and the inheritance and development of local folk culture and the continuous research on intangible cultural heritage can be a useful exploration. However, the development cost of the entire design is relatively high, and there is no unified construction standard and policy support for such projects in China, especially the lack of effective support from the network application platform, which makes it difficult to implement online, and the reproducibility is low.