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The variations in precipitation have displayed a complex pattern in different regions since the mid-to-late-Holocene. Cloud formation processes may have a significant impact on precipitation, especially during the tropical marine processes and summer monsoon which convey abundant water vapor to coastal southern China and inland areas. Here, we use two 7500 year sedimentary records from the Pearl River Delta and the closed Maar Lake, respectively, in coastal southern China to reconstruct the mid-to-late-Holocene humidity variability and explore its possible relationship with cloud cover modulated by the Earth's magnetic fields (EMF). Our proxy records document an apparent increase in wetness in coastal southern China between 3.0 and 1.8 kyr BP. This apparent increase in humidity appears to be consistent with the lower virtual axial dipole moments and, in turn, with a lower EMF. This correlation suggests that the EMF might have been superimposed on the weakened monsoon to regulate the mid-to-late-Holocene hydroclimate in coastal southern China through the medium of galactic cosmic rays, aerosols, and cloud cover. However, further investigations are needed to verify this interaction. [ABSTRACT FROM AUTHOR]

Purpose: Compare the value of imaging using positron 18F-labeled fibroblast activation protein inhibitor-42 (18F-FAPI-42) and 18F-labeled deoxyglucose (18F-FDG) for assessment of AKI. Procedures: This study analyzed cancer patients who received 18F-FAPI-42 and 18F-FDG PET/CT imaging. Eight patients had AKI with bilateral ureteral obstruction (BUO), eight had BUO (CKD1–2) with no acute kidney disease (AKD), and eight had no ureteral obstruction (UO) with normal renal function. The average standardized uptake value (SUVave) of the renal parenchyma (RP-SUVave), the blood pool SUVave (B- SUVave), SUVave in the highest region of the renal collective system (RCS-SUVave), and the highest serum creatinine level (top SCr) were recorded. Results: The 18F-FAPI-42 and 18F-FDG results showed that radiotracer of renal parenchyma was more concentrated in the AKI group than in the other two groups, whereas the RP-SUVave from 18F-FAPI-42 was higher than that from 18F-FDG in the AKI group (all P < 0.05). 18F-FAPI-42 imaging in the AKI group showed uptake by the renal parenchyma with a diffuse increase, but very little radiotracer in the renal collecting system, similar to a "super kidney scan." The renal parenchyma also had an increase of SUVave, with accumulation of radiotracer in the renal collecting system. AKI was more severe when a patient had a "super kidney scan" in both kidneys (P < 0.05). The B-SUVave level was higher in the AKI group than in the other two groups in 18F-FAPI-42 (both P < 0.05). Conclusions: 18F-FAPI-42 imaging had higher RP-SUVave than 18F-FDG imaging in cancer patients who had BUO with AKI. An increased renal parenchyma uptake in both kidneys and low radiotracer distribution in the collecting system suggest more severe AKI. [ABSTRACT FROM AUTHOR]

As an essential tool to bridge the gap between climatic output and hydrological input, the precipitation spatial downscaling (PSD) method exhibits divergent performance in terms of different evaluation objectives. This study compared and analysed the performance of the three PSD methods using two evaluation objectives - precipitation (P) and possible effective precipitation (PEP), and evaluated the effect of different downscaled precipitation on regional flow simulation by constructing an ideal model and a real case based on the Vertical Mixed Runoff (VMR) model. Results show that when the evaluation objective changes from P to PEP, the Artificial Neural Network replaces the Weather Research & Forecasting Model as the dominant PSD model. In spatial analysis, the statistical PSD models perform significantly better when using PEP, compared to P. In temporal analysis, the PEP biases are more stable compared to the P biases from the same PSD model. The validation in the ideal case and the actual basin further proves that taking PEP as the evaluation objective can improve the reliability of the PSD method selection for hydrological research. [ABSTRACT FROM AUTHOR]

Accidental cable failure may occur for complicated suspend-dome structures, resulting in the dynamic impact effect on structures. This study presents simplified analysis methods for evaluating suspend-dome structures when sudden cable failure occurs. An implicit analysis method of improved alternative load path (IAM-IAP) was employed to simply simulate the cable failure process of the beam-string structure. The IAM-IAP was also validated by comparing the calculated results with the existing test results for the truss string structure. The parameters of the cable failure process (i.e., failure time, failure path, and damping ratio) were analyzed, and suitable values were recommended. Based on the IAM-IAP, a finite element model of multi-loop cable-string suspend-dome structure (MCSS) was established and benchmarked by verifying the static responses during construction. Dynamic responses (i.e., time histories, displacements, axial forces, and dynamic amplification factors) of MCSS were systematically investigated. The dynamic amplification factor may be larger than 2, exceeding the suggested value of existing specifications. A static equivalent method with reasonable prediction accuracy was also proposed to simply assess the dynamic responses of suspend-dome structures subjected to sudden cable failure. [ABSTRACT FROM AUTHOR]

In order to efficiently and automatically identify the faults of rotating machinery, so as to avoid the dangers and losses caused by them, this paper proposes a new fault feature extraction method for rotating machinery named Hierarchical Multi-variate Amplitude-aware Permutation Entropy (HmvAAPE), which has integrated the advantages of Amplitude-aware Permutation Entropy (AAPE), multi-channel analysis method and hierarchical decomposition method. Therefore, the features extracted by this feature extraction method can contain more complete fault information. The t-SNE algorithm is chosen to conduct dimensional reduction of features and the Kernel Extreme Learning Machine optimized by Von Neumann Topology Whale Optimization Algorithm (VNWOA-KELM) is proposed to learn fault characteristics and classify faults automatically. By designing bearing and gearbox fault experiments and collecting their fault data to verify the effectiveness of the proposed method, it can be obtained that the average classification accuracy of this method can reach 98.9%. Through comparative experiments, conclusions can be made that this method can get both higher accuracy and higher stability at the same time. [ABSTRACT FROM AUTHOR]

Highlights: A novel Ni(OH)2-based catalyst with ultralow Ni–Ni coordination is produced, exhibiting high activity (100 mA cm−2 at 1.39 V for methanol oxidation reactions) and outstanding stability in an industrial concentration electrolyte (over 500 mA cm−2 in 6 M KOH). Mechanistic studies show that the improved kinetics and durability are primarily due to ultralow Ni–Ni coordination, 3D-networking structures and the Mo dopant. Electrocatalytic water splitting is a viable technique for generating hydrogen but is precluded from the sluggish kinetics of oxygen evolution reactions (OER). Small molecule oxidation reactions with lower working potentials, such as methanol oxidation reactions, are good alternatives to OER with faster kinetics. However, the typically employed Ni-based electrocatalysts have poor activity and stability. Herein, a novel three-dimensional (3D)-networking Mo-doped Ni(OH)2 with ultralow Ni–Ni coordination is synthesized, which exhibits a high MOR activity of 100 mA cm−2 at 1.39 V, delivering 28 mV dec−1 for the Tafel slope. Meanwhile, hydrogen evolution with value-added formate co-generation is boosted with a current density of more than 500 mA cm−2 at a cell voltage of 2.00 V for 50 h, showing excellent stability in an industrial alkaline concentration (6 M KOH). Mechanistic studies based on density functional theory and X-ray absorption spectroscopy showed that the improved performance is mainly attributed to the ultralow Ni–Ni coordination, 3D-networking structures and Mo dopants, which improve the catalytic activity, increase the active site density and strengthen the Ni(OH)2 3D-networking structures, respectively. This study paves a new way for designing electrocatalysts with enhanced activity and durability for industrial energy-saving hydrogen production. [ABSTRACT FROM AUTHOR]

Long-cycle stability and high-energy density are big challenges for developing high-performance hybrid supercapacitor (HSC) electrode materials. In this work, molybdenum-doped Co3O4 nanosheets arrays on nickel foam (noted as MoxCo1.5−xO/NF) are successfully prepared via facile one-step electrodeposition followed by annealing for hybrid supercapacitors. The experimental and calculated results indicate that the band gap modification and conductivity enhancement of MoxCo1.5−xO lead to excellent capacitive performance due to the doping of Mo into Co3O4. The as-prepared Mo0.25Co1.25/NF electrode demonstrates a high specific capacity of 128.2 mAh g−1 (923 F g−1) at 1 A g−1 (60% higher than the undoped Co3O4) and superior cycle stability with 95.2% capacity retention after 10,000 cycles at 10 A g−1. The assembled HSC delivers high-energy density of 64.3 Wh kg−1 at the power density of 794.1 W kg−1 and with 87.7% capacity retention after 10,000 cycles. This work can present a new strategy to fabricate the three-dimensional high-performance integrated electrode materials by a facile electrodeposition for heteroatom-doped transition metal oxide for high-performance supercapacitors. [ABSTRACT FROM AUTHOR]

As a mainstream computing and storage strategy for mobile communications, Internet of Things and large data applications, mobile edge computing strategy mainly benefits from the deployment and allocation of small base stations. Mobile edge computing mainly helps users to complete complex, intensive and sensitive computing tasks. However, the algorithm has many problems in practical application, such as complex user needs, complex user mobility, numerous services and applications. Therefore, under the above background, it is of great significance to solve the computational pressure of current mobile edge algorithm and optimize its algorithm architecture. This paper creatively proposes a deep learning architecture based on tightly connected network, and transplants it into mobile edge algorithm to realize the payload sharing process of edge computing, so as to establish an efficient network model. At the same time, we creatively propose a multi-task parallel scheduling algorithm, which realizes the mobile edge algorithm in the face of complex computing and algorithm efficiency. Finally, the above algorithms are simulated and tested. The experimental results show that under the same task, the time consumed by the proposed algorithm is 3.5–4, while the time consumed by the traditional algorithm is 4.5–8, and the corresponding time is standardized time, so the practice shows that the algorithm has obvious overall efficiency advantages. [ABSTRACT FROM AUTHOR]

To improve the anti-noise ability of credibilistic intuitionistic fuzzy c-means clustering method (CIFCM) for image segmentation, this paper proposes a robust credibilistic intuitionistic fuzzy c-means clustering method based on credibility of pixels and intuitionistic fuzzy entropy. Firstly, a new similarity measure is constructed by utilizing the grayscale and spatial relationship between the current pixel and its neighborhood pixels. Secondly, it is embedded into the objective function of credibilistic intuitionistic fuzzy c-means clustering, and a new robust clustering method with spatial constraints is presented to effectively solve the segmentation problem of image corrupted by high noise. In the end, the convergence of this proposed robust clustering method is strictly proved by iterated convergence theorem. Experimental results show that proposed algorithm has better noise-suppression ability and more satisfactory segmentation results than CIFCM algorithm. [ABSTRACT FROM AUTHOR]

Uranium (U) (or U/Ca ratio) in speleothems has been suggested to be an indicator of soil humidity and effective rainfall in the Asian summer monsoon region. However, this argument has not yet been confirmed in modern cave monitoring studies. A 3-year (July 2011–August 2014) cave monitoring study was conducted to explore the seasonal variations of U in karstic waters (including cave water and river water) from Northeastern Sichuan, Central China and to gain a better understanding of the processes influencing the U variations in these waters. With the exception of some pool waters, U concentrations and U/Ca ratios of cave and river waters exhibit seasonal variations with relatively higher values occurring in the winter half year and lower values in the summer half year, anti-correlated with the seasonal variations of local rainfall amount. Soil redox conditions, which are controlled by soil moisture and hence effective precipitation, may have a significant influence on the seasonal variations of U in waters. We demonstrate that speleothem U concentrations and/or U/Ca ratios could serve as a potential proxy, at least at the study site, for the regional effective rainfall. [ABSTRACT FROM AUTHOR]

High-strength structural steel is the tendency in modern construction practice. In this study, quasi-static tension tests and dynamic tests for Q550 with strain rate from 0.00025 to 3831 s−1 were conducted. The results showed that Q550 is dependent on the strain rate, keeping the flow stress increased as the strain rate increases, while Q550 has lower strain-rate sensitivity of flow stress than that of normal mild steel. Based on the experimental data, a proper constant for the key parameter, C, in Johnson–Cook model (J–C) was suggested. Then, a modified J–C model based on a rate-dependent parameter C ε ˙ was recommended to consider the influence of strain-rate effect. New constants of D and p governing the dynamic response of steel in the Cowper–Symonds (C–S) model were also suggested. The C–S model and J–C models with suggested constants provided in the paper were proven to have acceptable prediction accuracy for the dynamic increase factor of Q550. These results may be applied to study the dynamical properties of Q550 and related structural components for future engineering applications. [ABSTRACT FROM AUTHOR]

A new aromatic porous organic polymeric material named as N-PKIN has been successfully constructed. The electron-rich benzene in its microstructure can donate the electron density to the neighboring indole and carbonyl groups to further enhance the local dipole-π and dipole-quadrupole binding abilities to the CO2 molecules for effectively facilitating the adsorbent to attract CO2 selectively. As a result, this porous organic polymer showed outstanding CO2 absorption capacity and high CO2/N2, CO2/CH4 selectivity. In addition, upon exposure to humid condition, the porous organic polymer still kept high CO2 capture capacity and selectivity. Moreover, we have demonstrated that the CO2 absorption process is fully reversible. [ABSTRACT FROM AUTHOR]

Cheyletus malaccensis is a predatory mite widely distributed in grain storages. It has been regarded as an important biological control agent for pest mites. In this study, we investigated the population genetic structure of C. malaccensis distributed in China based on the partial regions of mitochondrial COI and 12S rRNA genes. We collected 256 individuals of C. malaccensis from stored grain in 34 sites of China. We detected 50 COI gene haplotypes and nine 12S rRNA gene haplotypes. There were three clades in the haplotype network and Bayesian and maximum parsimony phylogenetic trees based on COI sequences, and two based on 12S rRNA sequences. The clustering of haplotypes was not correlated with their geographical distributions. The analysis of molecular variance, AMOVA, indicated that the genetic differentiation between populations was relatively weak. The major genetic differentiation was found within populations. We suggest that the genetic structure of C. malaccensis observed in this study may be the result of long-term climate fluctuations and recent human disturbances. [ABSTRACT FROM AUTHOR]

A new method regarding mesomechanics finite-element research is proposed to predict the peak shear strength of mudded intercalation materials on a mesoscopic scale. Based on geometric and mechanical parameters, along with the strain failure criteria obtained by sample's deformation characteristics, uniaxial compression tests on the sample were simulated through a finite-element model, which yielded values consistent with the data from the laboratory uniaxial compression tests, implying that the method is reasonable. Based on this model, a shear test was performed to calculate the peak shear strength of the mudded intercalation, consistent with values reported in the literature, thereby providing a new approach for investigating the mechanical properties of mudded intercalation materials. [ABSTRACT FROM AUTHOR]

Directional samples were taken to study rock magnetism and palaeomagnetic records from the Dongsheng profile, which is 5 m thick and on the northwest edge of the Bose Basin. Mineralogy and rock magnetism of typical samples indicate that coarse granular titanomagnetite, and fine-grained hematite, superparamagnetic maghemite formed by pedogenesis are in the sediment, which has undergone many transformative processes during different stages of pedogenesis. Parallel samples were taken for thermal demagnetization (TH) (0 to 680°C) and alternating field (AF) demagnetization (0 to 80 mT) respectively. Experimental results of these two kinds of demagnetization illustrate that there are two or more magnetic components in the samples. Intensity of NRM decreases by almost 60% to 90% rapidly when the temperature ranges from 100°C to 350°C, with a steady magnetic component. It is impossible to analyze the magnetic components at high temperature because those fluctuate widely when the temperature is higher than 400°C. Steady magnetic components from 100°C to 350°C indicate that the remanence was mainly carried by fine-grained hematite formed by pedogenesis, reflecting a change in the geomagnetic field while the magnetite was being oxidized into hematite by chemical weathering after deposition. The formative age of the sediments cannot be obtained by magnetic methods in this profile. [ABSTRACT FROM AUTHOR]

Magnetic parameters and their environmental implications of sediments in a core (PD) from the Pearl River Delta, South China, indicate that ferrimagnetic minerals with low coercivity, such as magnetite, dominate the magnetic properties although small amounts of Fe-sulphides occur. The fraction of Fe-sulphides increases and becomes the dominant minerals determining the magnetic characteristics in grey-black organic-rich clay horizons, indicating an anoxic, sulphate-reducing swamp environment resulting from a marine regression. In the “Huaban clay”, hard magnetic minerals, such as hematite and goethite, largely control the magnetic properties of the sediments and imply a long period of exposure and weathering. Where magnetite is the main magnetic mineral, its fraction and grain size determine properties such as magnetic susceptibility ( κ) and saturation isothermal remanent magnetization (SIRM). Ratios of SIRM/ κ and χ arm/SIRM reflect changes in sea level with high SIRM/ κ and χ arm/SIRM correlating with a smaller magnetic mineral grain size and rising sea level. Based on downcore variations of these environmental magnetic parameters along with sediment characteristics and microfauna, the sedimentary environment of the Pearl River Delta area can be divided into two main cycles of transgression and regression during the late Pleistocene and Holocene with more sub-cycles of sea level fluctuation during each transgression. [ABSTRACT FROM AUTHOR]

Low-frequency grab sampling cannot capture fine dynamics of stream solute concentrations, which results in large uncertainties in load estimates. The recent development of high-frequency sensors has enabled monitoring solute concentrations at sub-hourly time scales. This study aimed to improve nitrate (NO3) load estimates using high-resolution records (15-min time interval) from optical sensors to capture the typical concentration response to storm events. An empirical model was developed to reconstruct NO3 concentrations during storm events in a 100-km2 agricultural catchment in Germany. Two years (Jan 2002 to Dec 2002 and Oct 2005 to Sep 2006) of high-frequency measurements of NO3 concentrations, discharge and precipitation were used. An Event Response Reconstruction (ERR) model was developed using NO3 concentration descriptor variables and predictor variables calculated from discharge and precipitation records. Fourteen events were used for calibration, and 27 events from four periods of continuous records of high-frequency measurement were used for validation. During all selected storm events, NO3 concentration decreased during flow rise and increased during the recession phase of the hydrograph. Three storm descriptor variables were used to describe these dynamics: relative change in concentration between initial and minimum NO3 concentrations (rdN), time to maximum change in NO3 concentration (TdN) and time to 50% recovery of NO3 concentration (TNrec). The ERR consisted of building linear models of discharge and precipitation to predict these three descriptors. The ERR approach greatly improved NO3 load estimates compared to linear interpolation of grab sampling data (error decreased from 10 to 1%) or flow-weighted estimation of load (error is 7%). This study demonstrated that ERR based on a few months of high-resolution data enables accurate load estimates from low-frequency NO3 data. [ABSTRACT FROM AUTHOR]

Camellia oleifera is a subtropical evergreen plant. Cultivated C. oleifera is the most important woody oil crop in China. Wild C. oleifera is an essential genetic resource for breeding. The patterns of genetic differentiation among altitudes/latitudes in wild C. oleifera are still unknown. Camellia oleifera may be predominantly hexaploid. The characteristics of polyploidy may lead to considerable biases in estimates of genetic diversity and differentiation. Our study used C. oleifera as a case study for analysing genetic diversity, structure and differentiation in polyploid plants using simple sequence repeats (SSRs). Wild C. oleifera samples were collected at different altitudes on the Jinggang and Lu mountains of China. The ploidy levels were determined with flow cytometry analysis. Eight highly polymorphic SSRs were used to genotype the samples. Genetic diversity and structure were analysed. Various estimates of genetic differentiation were compared. The flow cytometry results indicated that wild C. oleifera samples were all hexaploid at various altitudes of the Jinggang and Lu mountains. High levels of genetic diversity were found on both the Jinggang and Lu mountains. Genetic structure analyses indicated clear genetic differentiation between the Jinggang and Lu mountains and lower genetic differentiation among altitudes within each mountain. Classical genetic differentiation estimates of Fst failed to discriminate genetic differentiation between and within mountains. The Rho statistic showed a moderate level of genetic differentiation between mountains and lower levels of genetic differentiation within each mountain. Our study demonstrates that Rho is the statistic of choice for estimating genetic differentiation in polyploids. [ABSTRACT FROM AUTHOR]

Geomagnetic excursions during Brunhes epoch have been brought to the forefront topic in paleomagnetic study, as they provide key information about Earth’s interior dynamics and could serve as another tool for stratigraphic correlation among different lithology. Loess-paleosol sequences provide good archives for decoding geomagnetic excursions. However, the detailed pattern of these excursions was not sufficiently clarified due to pedogenic influence. In this study, paleomagnetic analysis was performed in loess-paleosol sequences on the northern piedmont of the Tianshan Mountains (northwestern China). By radiocarbon and luminance dating, the loess section was chronologically constrained to mainly the last c.130 ka, a period when several distinct geomagnetic excursions were involved. The rock magnetic properties in this loess section are dominated by magnetite and maghemite in a pseudo-single-domain state. The rock magnetic properties and magnetic anisotropy indicate weakly pedogenic influence for magnetic record. The stable component of remanent magnetization derived from thermal demagnetization revealed the presence of two intervals of directional anomalies with corresponding intensity lows in the Brunhes epoch. The age control in the key layers indicates these anomalies are likely associated with the Laschamp and Blake excursions, respectively. In addition, relative paleointensity in the loess section is basically compatible with other regional and global relative paleointensity records and indicates two low-paleointensity zones, possibly corresponding to the Blake and Laschamp excursions, respectively. As a result, this study suggests that the loess section may have the potential to record short-lived excursions, which largely reflect the variation of dipole components in the global archives. [ABSTRACT FROM AUTHOR]