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Melatonin (MT), an indole compound, can boost plant growth under abiotic stress conditions. This experiment aims to elucidate the synergistic effect of MT and ascorbic acid (AsA) in mitigating salinity stress by assessing the photosynthetic and antioxidant capacity of the maize inbred lines H123 and W961. The results indicated that exogenous MT and AsA significantly improved photosynthetic efficiency and biomass of maize under salinity stress. Additionally, exogenous MT and AsA also improved antioxidant enzyme activities, promoted regeneration of AsA and GSH, decreased reactive oxygen species contents, suppressed Na+ accumulation, and improved the K+/Na+ ratio of maize seedlings. Additionally, the AsA inhibitor lycorine decreased the endogenous content of AsA and eliminated the positive effects of MT, while the MT inhibitor p-chlorophenyl alanine (CPA) reduced the endogenous content of MT, which could not eliminate the promoting effects of AsA. The results suggested that AsA may act as a downstream signal involved in the regulatory effects of MT on maize under salinity stress.

Comprehensive measurements are vital to obtain big enough datasets for better understanding the complex atmosphere and further improving the air quality. To investigate the 4-year variation of air quality and the influences of special events (Beijing Winter Olympics, COVID lockdown and Chinese New Year) on it during the wintertime in polluted urban air, we conducted comprehensive observations in Beijing, China, during 1 January–20 February, in the years from 2019 to 2022. The mass concentration of PM2.5 and its composition (organics, nitrate, sulfate, ammonium, chloride and black carbon) and the number size distributions of particles (down to ∼1 nm) and ions, gaseous pollutants (CO, NOx, SO2, O3) and condensable vapors (sulfuric acid and oxygenated organic molecules), as well as meteorological parameters, were simultaneously measured. The days before 22 January without any special events in each year were selected to investigate the 4-year variability of air quality. We found that the concentrations of CO, NOx, total oxygenated organic molecules (OOMs), total PM2.5, organics, chloride and black carbon and the number concentration of sub-3 nm particles (N1.3−3) showed similar variations, decreasing from 2019 to 2021 and then increasing in 2022. For SO2, however, its concentration decreased year by year due to the significant emission reduction, further leading to the decrease of gaseous sulfuric acid and particulate sulfate from 2019 to 2022. O3 concentration showed an opposite 4-year variation compared with NOx. Meanwhile, both the oxygen and nitrogen contents of oxygenated organic molecules increased year by year, implying that not only the oxidation state of those compounds increased, but also NOx was involved more efficiently in their formation processes. With higher sulfuric acid concentrations and new particle formation (NPF) frequencies in 2021 than in 2022, and with the lowest concentrations of background aerosols and the lowest ambient temperatures in 2021, N1.3−3 was still the lowest in 2021. Unlike N1.3−3, the ion concentrations in both 0.8–2 and 2–4 nm size ranges were higher in 2021 than in the other years. Then, the days after 4 February were chosen to explore the influence of special events. The non-event days within this date range in 2019 and 2021 were chosen as the reference period. Due to the favorable meteorological conditions together with reductions in anthropogenic emissions, there were basically no haze events during the Olympics. Therefore, CO, NOx, SO2, total OOMs, accumulation-mode particles (N100−1000), and total PM2.5 and its composition were much lower, while ion concentrations were much higher compared with the reference period. Although there was also emission reduction during COVID, especially for NOx, the enhancement of secondary inorganic aerosol formation, together with unfavorable meteorological conditions, caused severe haze events during this period. Hence, CO, total OOMs and all PM2.5 compositions during COVID increased dramatically compared with the reference period. Influenced by SO2, condensation sink and sunlight, sulfuric acid concentration was found to be comparable between the Olympics and the reference period but was lower during COVID and Chinese New Year. Additionally, N1.3−3 was almost at the same level during different periods, indicating that the special events only had little impact on the NPF processes. These results provide useful information to the development of more targeted pollution control plans.

Remote sensing data is a primary means of obtaining information about the Earth's surface, widely used in various fields such as geographic information, natural resource management, urban planning, and environmental monitoring. However, due to the large volume and high complexity of remote sensing image data obtained from satellites, drones, and other equipment, efficient processing of this data and visualization of the results have become important issues. This paper presents a Cesium-based platform for visualizing multi-source remote sensing data, aimed at contributing to urban development efforts and providing additional insights for surveying education.This platform allows users to intuitively understand the spatial distribution and dynamic changes of remote sensing data. It not only integrates different types of remote sensing data into a unified 3D scene but also allows users to interact with the data according to their needs. A Cesium-based urban visualization platform was developed to display the geographic location of a specific region in Hong Kong and provide spatial measurement functions. This platform has wider applications in surveying and mapping education, as it can incorporate more remote sensing and geospatial data, allowing for increased student-teacher interaction and helping students better understand surveying and mapping concepts.Focusing on the construction of smart cities, the platform improves spatial awareness and interactivity for urban planning and management. Moreover, the platform has great potential in surveying and mapping education, providing a more immersive learning experience for students and cultivating talents in the field.

Three-dimensional numerical simulations are performed to examine the effects of dynamic wing morphing of a hummingbird-inspired flexible flapping wing on its aerodynamic performance in hovering flight. The range analysis and variation analysis in the orthogonal experiment are conducted to assess the significance level of various deformations observed in the hummingbird wings on wing aerodynamic performance. It has been found that both camber and twist significantly can affect lift, and twist has an even higher significant impact on lift efficiency. Spanwise bending, whether out-of-stroke-plane or in-stroke-plane, has a negligible impact on lift and efficiency, and the in-stroke-plane bending can cause lift to decrease to an extent. Optimal parameters for determining the wing deformations are selected and tested to validate the conclusions drawn in the analysis for the results in orthogonal experiment. Through a comparison study between the optimized wings and the rigid wing, it is found that although the wing flexibility can cause the net force to decrease, the flexible wing used less energy to bring the net force closer to the vertical direction, thereby improving the lift efficiency. This study provides an aerodynamics understanding of the efficiency improvement of the hummingbird-inspired flexible flapping wing.

Soft-elasticity in monodomain liquid crystal elastomers (LCEs) is promising for impact-absorbing applications but due to the lack of synthetic procedures which give monodomain devices of sufficient size, impact studies on LCEs have not been performed. Here the authors use direct-ink writing to fabricate bulk monodomain LCE devices and study their compressive soft-elasticity.

In order to solve the problem that the source of LiDAR data error needs to be adjusted and the data volume is large, the adjustment speed between the voyages is slow and cannot be automatically adjusted. Based on the iterative nearest point (ICP) algorithm, this paper proposes an improved iterative closest point (ICP) algorithm based on GPU parallel octree. The algorithm quickly constructs the octree of LiDAR nautical belt data in the GPU, uses the octree to quickly find the overlapping area of the nautical band, and then uses the ICP algorithm in the overlapping area to solve the adjustment parameters R and T quickly. Then the entire flight belt is quickly adjusted. Experiments with example data show that this method can quickly and automatically adjustment a large number of LiDAR data, and the adjustment precision can meet the precision requirements of the production.

Due to the influence of the occlusion of objects or the complexity of the measured terrain in the scanning process of airborne lidar, the point cloud data inevitably appears holes after filtering and other processing. The incomplete data will inevitably have an impact on the quality of the reconstructed digital elevation model, so how to repair the incomplete point cloud data has become an urgent problem to be solved. To solve the problem of hole repair in point cloud data, a hole repair algorithm based on improved moving least square method is proposed in this paper by studying existing hole repair algorithms. Firstly, the algorithm extracts the boundary of the point cloud based on the triangular mesh model. Then we use k-nearest neighbor search to obtain the k-nearest neighbor points of the boundary point. Finally, according to the boundary point and its k-nearest neighbor point, the improved moving least squares method is used to fit the hole surface to realize the hole repair. Combined with C++ and MATLAB language, the feasibility of the algorithm is tested by specific application examples. The experimental results show that the algorithm can effectively repair the point cloud data holes, and the repairing precision is high. The filled hole area can be smoothly connected with the boundary.

The real-time measurements of NH3 and trace gases were conducted, in conjunction with semi-continuous measurements of water-soluble ions in PM2.5 at a rural site in the North China Plain (NCP) from May to September 2013 in order to better understand chemical characteristics of ammonia and the impact of secondary ammonium aerosols on formation in the NCP. Extremely high NH3 and NH4+ concentrations were observed after a precipitation event within 7–10 days following urea application. Elevated NH3 levels coincided with elevated NH4+, indicating that NH3 likely influenced particulate ammonium mass. For the sampling period, the average conversion ∕ oxidation ratios for NH4+ (NHR), SO42− (SOR), and NO3− (NOR) were estimated to be 0.30, 0.64, and 0.24, respectively. The increased NH3 concentrations, mainly from agricultural activities and regional transport, coincided with the prevailing meteorological conditions. The high NH3 level with NHR of about 0.30 indicates that the emission of NH3 in the NCP is much higher than needed for aerosol acid neutralisation, and NH3 plays an important role in the formation of secondary aerosols as a key neutraliser. The hourly data obtained were used to investigate gas–aerosol partitioning characteristics using the thermodynamic equilibrium model ISORROPIA-II. Modelled SO42−, NO3−, and NH3 values agree well with the measurements, while the modelled NH4+ values largely underestimate the measurements. Our observation and modelling results indicate that strong acids in aerosol are completely neutralised. Additional NH4+ exists in aerosol, probably a result of the presence of a substantial amount of oxalic and other diacids.

Increases in nitrogen (N) deposition can greatly stimulate ecosystem net carbon (C) sequestration through positive N-induced effects on plant productivity. However, how net ecosystem CO2 exchange (NEE) and its components respond to different N addition rates remains unclear. Using an N addition gradient experiment (six levels: 0, 2, 4, 8, 16, 32 gN m−2 yr−1) in an alpine meadow on the Qinghai–Tibetan Plateau, we explored the responses of different ecosystem C fluxes to an N addition gradient and revealed mechanisms underlying the dynamic responses. Results showed that NEE, ecosystem respiration (ER), and gross ecosystem production (GEP) all increased linearly with N addition rates in the first year of treatment but shifted to N saturation responses in the second year with the highest NEE (−7.77 ± 0.48 µmol m−2 s−1) occurring under an N addition rate of 8 gN m−2 yr−1. The saturation responses of NEE and GEP were caused by N-induced accumulation of standing litter, which limited light availability for plant growth under high N addition. The saturation response of ER was mainly due to an N-induced saturation response of aboveground plant respiration and decreasing soil microbial respiration along the N addition gradient, while decreases in soil microbial respiration under high N addition were caused by N-induced reductions in soil pH. We also found that various components of ER, including aboveground plant respiration, soil respiration, root respiration, and microbial respiration, responded differentially to the N addition gradient. These results reveal temporal dynamics of N impacts and the rapid shift in ecosystem C fluxes from N limitation to N saturation. Our findings bring evidence of short-term initial shifts in responses of ecosystem C fluxes to increases in N deposition, which should be considered when predicting long-term changes in ecosystem net C sequestration.

Playing an important role in local and national seaport activities, container wharves are susceptible to structural failure and damage during earthquake events. Therefore, factors that affect the seismic response of crane–wharf structures under different types of earthquake ground motions should be elucidated. In this paper, 3D finite element models were established to investigate the differences of natural vibration characteristics between the wharf and crane–wharf structures. The dynamic response of a typical pile-supported wharf structure and the interaction behavior of a crane and wharf structural system under seismic actions of near-field and far-field ground motions were studied by performing numerical simulation and time-history response analysis. Axial force–moment relation curves were adopted to analyze the elastic–plastic limit state of the wharf structure under different ground motions. Results showed that the consideration of the container crane increased the natural vibration period of the pile-supported wharf structure and affected the dynamic characteristics of the structure. Compared with the far-field earthquake ground motion, the nearfield earthquake exerted a more significant impact on the structural dynamic response that controlled the elastic–plastic limit state. With the presence of a crane, the moment and shear force of the pile-top decreased and the location of the extreme value moved down obviously. The findings demonstrated that considering the crane changed the failure mechanism of the wharf structure, and the eccentric effect of the crane may amplify the dynamic response as the peak ground acceleration increases. The results provide reference for the seismic design and the evaluation of the seismic response of container wharves.

A grand challenge underlies the entire field of topology-enabled quantum logic and information science: how to establish topological control principles driven by quantum coherence and understand the time dependence of such periodic driving. Here we demonstrate a few-cycle THz-pulse-induced phase transition in a Dirac semimetal ZrTe_{5} that is periodically driven by vibrational coherence due to excitation of the lowest Raman active mode. Above a critical THz-pump field threshold, there emerges a long-lived metastable phase, approximately 100 ps, with unique Raman phonon-assisted topological switching dynamics absent for optical pumping. The switching also manifests itself by distinct features: nonthermal spectral shape, relaxation slowing near the Lifshitz transition where the critical Dirac point occurs, and diminishing signals at the same temperature that the Berry-curvature-induced anomalous Hall effect magnetoresistance vanishes. These results, together with first-principles modeling, identify a mode-selective Raman coupling that drives the system from strong to weak topological insulators with a Dirac semimetal phase established at a critical atomic displacement controlled by the phonon coherent pumping. Harnessing of vibrational coherence can be extended to steer symmetry-breaking transitions, i.e., Dirac to Weyl ones, with implications for THz topological quantum gate and error correction applications.

Glass-forming ability (GFA) is crucial for designing bulk metallic glasses. In this work, it was found that when the content of the solvent element with an atomic radius larger than 1.58 Å in one ternary alloy system is fixed, their entropy of mixing (ΔSmix) vs. the enthalpy of mixing (ΔHmix) curve display a slant arc shape. The compositions locating around the inflection point of each ΔHmix vs. ΔSmix curve usually show an optimal GFA. Its feasibility was verified in Zr-, La-, and Ca-based ternary systems. By considering both calculated inflection points and experimental results, the optimizing glass-forming compositions can be roughly estimated by a proposed formula under limited conditions. Our studies could provide a simple method for preliminarily selecting good glass-formers when the content of the solvent element in one ternary alloy system is fixed.

Hurricanes are infrequent but influential disruptors of ecosystem processes in the southeastern Atlantic and Gulf coasts. Every southeastern forested wetland has the potential to be struck by a tropical cyclone. We examined the impact of Hurricane Hugo on two paired coastal South Carolina watersheds in terms of streamflow and vegetation dynamics, both before and after the hurricane's passage in 1989. The study objectives were to quantify the magnitude and timing of changes including a reversal in relative streamflow difference between two paired watersheds, and to examine the selective impacts of a hurricane on the vegetative composition of the forest. We related these impacts to their potential contribution to change watershed hydrology through altered evapotranspiration processes. Using over 30 years of monthly rainfall and streamflow data we showed that there was a significant transformation in the hydrologic character of the two watersheds – a transformation that occurred soon after the hurricane's passage. We linked the change in the rainfall–runoff relationship to a catastrophic change in forest vegetation due to selective hurricane damage. While both watersheds were located in the path of the hurricane, extant forest structure varied between the two watersheds as a function of experimental forest management techniques on the treatment watershed. We showed that the primary damage was to older pines, and to some extent larger hardwood trees. We believe that lowered vegetative water use impacted both watersheds with increased outflows on both watersheds due to loss of trees following hurricane impact. However, one watershed was able to recover to pre hurricane levels of evapotranspiration at a quicker rate due to the greater abundance of pine seedlings and saplings in that watershed.

In this study, electrical and structural remodeling of ventricles was examined in tachycardia-induced heart failure (HF). We studied two groups of weight-matched adult male mongrel dogs: a sham-operated control group (n=5) and a pacing group (n=5) that underwent ventricular pacing at 230 bpm for 3 weeks. Clinical symptoms of congestive HF were observed in both groups. Their hemodynamic parameters were determined and the severity of the HF was evaluated by M-mode echocardiography. Changes in heart morphology were observed by scanning electron and light microscopy. Ventricular action potential duration (APD), as well as the 50 and 90% APD were measured in both groups. All dogs exhibited clinical symptoms of congestive HF after rapid right ventricular pacing for 3 weeks. These data indicate that rapid, right ventricular pacing produces a useful experimental model of low-output HF in dogs, characterized by biventricular pump dysfunction, biventricular cardiac dilation, and non-ischemic impairment of left ventricular contractility. Electrical and structural myocardial remodeling play an essential role in congestive HF progression, and should thus be prevented.

This paper proposed a novel method of decision fusion based on weights of evidence model (WOE). The probability rules from classification results from each separate dataset were fused using WOE to produce the posterior probability for each class. The final classification was obtained by maximum probability. The proposed method was evaluated in land cover classification using two examples. The results showed that the proposed method effectively combined multisensor data in land cover classification and obtained higher classification accuracy than the use of single source data. The weights of evidence model provides an effective decision fusion method for improved land cover classification using multi-sensor data.

We synthesized Mn3Zn0.9Cu0.1N by solid state reaction, and magnetic as well as electrical transport properties were investigated. It is found that Mn3Zn0.9Cu0.1N exhibits a first-order antiferromagnetism (AFM) to paramagnetic (PM) transition with the Néel temperature TN ~163 K, and substitution of Cu for Zn would favor ferromagnetism (FM) state and weaken AFM ground state, leading to a convex curvature character of M(T) curve. With high external fields 10 kOe–50 kOe, magnetic transition remains a robust AFM-PM feature while FM phase is completely suppressed. Thermal hysteresis of M(T) under 500 Oe is also suppressed when the magnetic field exceeds 10 kOe. Mn3Zn0.9Cu0.1N exhibits a good metallic behavior except for a slope change around TN, which is closely related to AFM-PM magnetic transition. Compared with the first differential of resistivity with respect to temperature for (dρ/dT)Mn3ZnN in transition temperature range, the absolute value of (dρ/dT)Mn3Zn0.9Cu0.1N is much lower which is close to zero.