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This study examines the collaborative approach in China-Africa satellite remote sensing initiatives based on solutions of satellite data acquiring, sharing and application experiences. It specifically addresses the data coverage requirements and current coverage scenarios of China's natural resources land satellites in Africa. By establishing the China-Africa Cooperation Centers on Satellite Remote Sensing Application, adopting a multi-level distributed technology center model, and implementing cross-continental remote sensing cloud services through an internet-based cloud platform, this initiative aims to enhance the direct utilization of satellite data in Africa. Furthermore, strategic satellite observation window designs tailored to seasonal changes have increased the frequency of valid coverage over the entire African continent to at least once a year. Such advancements pave the way for real-time monitoring applications, particularly in crucial areas such as sustainable development projects and disaster response efforts. Therefore, the study also provides some useful case studies that are anchored on the Sustainable Development Goals.

Naphthalene (Nap) and its derivatives, including 1-methylnaphthalene (1-MN) and 2-methylnaphthalene (2-MN), serve as prominent intermediate volatile organic compounds (IVOCs) and contribute to the formation of secondary organic aerosol (SOA). In this study, the Community Multiscale Air Quality (CMAQ) model coupled with detailed emissions and reactions of these compounds was utilized to examine their roles in the formation of SOA and other secondary pollutants in the Yangtze River Delta (YRD) region during summer. Significant underestimations of Nap and MN concentrations (by 79 % and 85 %) were observed at the Taizhou site based on the model results using the default emissions. Constrained by the observations, anthropogenic emissions of Nap and MN in the entire region were multiplied by 5 and 7, respectively, to better capture the evolution of pollutants. The average concentration of Nap reached 25 ppt (parts per trillion) in the YRD, with Nap contributing 4.1 % and 8.1 % (up to 12.6 %) of total aromatic emissions and aromatic-derived secondary organic carbon (SOC), respectively. The concentrations of 1-MN and 2-MN were relatively low, averaging 2 and 5 ppt, respectively. Together, they accounted for only 2.4 % of the aromatic-derived SOC. The impacts of Nap and MN oxidation on ozone and radicals were insignificant at regional scales but were not negligible when considering daily fluctuations in locations with high emissions of Nap and MN. This study highlights the significant roles of Nap and MN in the formation of SOA, which may pose environmental risks and result in adverse health effects.

Compressed Sensing (CS) has been shown to be an effective technique for improving the resolution of inverse synthetic aperture radar (ISAR) imaging and reducing the hardware requirements of radar systems. In this paper, our focus is on the l_p 0 p 1 model, which is a well-known non-convex and non-Lipschitz regularization model in the field of compressed sensing. In this study, we propose a novel algorithm, namely the Accelerated Iterative Support Shrinking with Full Linearization (AISSFL) algorithm, which aims to solve the l_p regularization model for ISAR imaging. The AISSFL algorithm draws inspiration from the Majorization-Minimization (MM) iteration algorithm and integrates the principles of support shrinkage and Nestrove's acceleration technique. The algorithm employed in this study demonstrates simplicity and efficiency. Numerical experiments demonstrate that AISSFL performs well in the field of ISAR imaging.

Volatile organic compounds (VOCs) play a crucial role in the formation of tropospheric ozone (O3) and secondary organic aerosols. VOC emissions are generally considered to have larger uncertainties compared to other pollutants, such as sulfur dioxide and fine particulate matter (PM2.5). Although predictions of O3 and PM2.5 have been extensively evaluated in air quality modeling studies, there has been limited reporting on the evaluation of VOCs, mainly due to a lack of routine VOC measurements at multiple sites. In this study, we utilized VOC measurements from the “Towards an Air Toxic Management System in China” (ATMSYC) project at 28 sites across China and assessed the predicted VOC concentrations using the Community Multiscale Air Quality (CMAQ) model with the widely used Multi-resolution Emission Inventory for China (MEIC). The ratio of predicted to observed total VOCs was found to be 0.74 ± 0.40, with underpredictions ranging from 2.05 to 50.61 ppbv (5.77 % to 85.40 %) at 24 sites. A greater bias in VOC predictions was observed in industrial cities in the north and southwest, such as Jinan, Shijiazhuang, Lanzhou, Chengdu, and Guiyang. In terms of different VOC components, alkanes, alkenes, non-naphthalene aromatics (ARO2MN), alkynes, and formaldehyde (HCHO) had prediction-to-observation ratios of 0.53 ± 0.38, 0.51 ± 0.48, 0.31 ± 0.38, 0.41 ± 0.47, and 1.21 ± 1.61, respectively. Sensitivity experiments were conducted to assess the impact of the VOC prediction bias on O3 predictions. While emission adjustments improved the model performance for VOCs, resulting in a change in the ratio of total VOCs to 0.86 ± 0.47, they also exacerbated O3 overprediction relative to the base case by 0.62 % to 6.27 % across the sites. This study demonstrates that current modeling setups and emission inventories are likely to underpredict VOC concentrations, and this underprediction of VOCs contributes to lower O3 predictions in China.

Diet intervention is emerging as an option to improve cancer therapy. Here, the authors show that a diet with restrictive cysteine and methionine synergizes with a ferroptosis inducer to increase cell death and survival in glioma preclinical models.

In recent years, audio positioning technology has been more favoured because it is not only highly accurate but also universally applicable to the mass users. In line with this trend, a chip dedicated to indoor positioning, the Kepler A100, has been released lately, which ranges by estimating the arrival time of the audio chirp. As with radio ranging techniques, sound-based ranging methods is subject to significant observation errors due to Non-Line-Of-Sight (NLOS) or multi-path effects, while Pedestrian Dead Reckoning (PDR) based on inertial data have the disadvantage of error accumulation. Both make localization challenging. In this paper, the ranging performance of the Kepler A100 chip is evaluated and experiments are conducted in two typical indoor scenarios to verify the stability and sub-metre accuracy of the ranging results. Meanwhile, this paper implements an indoor positioning system combining audio chirp/Micro-Electro-Mechanical Systems (MEMS)/floor map based on particle filtering algorithm. A new mapping constraint method is applied in the system, which can effectively constrain the particles in a reasonable space. Experiments are conducted in two complex office environments and the results show that the error of the proposed algorithm is about 0.65m in 95% of cases, a reduction of more than 40% compared to only-PDR or only-audio. The effectiveness and stability of the method is demonstrated.

We study the compound flooding processes that occurred in Hurricane Florence (2018), which was accompanied by heavy precipitation, using a 3D creek-to-ocean hydrodynamic model. We examine the important role played by barrier islands in the observed compound surges in the coastal watershed. Locally very high resolution is used in some watershed areas in order to resolve small features that turn out to be critical for capturing the observed high water marks locally. The wave effects are found to be significant near barrier islands and have contributed to some observed over-toppings and breaches. Results from sensitivity tests applying each of the three major forcing factors (oceanic, fluvial, and pluvial) separately are succinctly summarized in a “dominance map” that highlights significant compound effects in most of the affected coastal watersheds, estuaries, and back bays behind the barrier islands. Operational forecasts based on the current model are being set up at NOAA to help coastal resource and emergency managers with disaster planning and mitigation efforts.

Understanding how cells discriminate between stimuli is an ongoing challenge. Here, the authors propose a mathematical framework for inferring the mutual information encoded in temporal signaling dynamics and use it to study how information is transmitted over time in response to different stimuli in NFκB, MAPK and p53 signaling pathways.

Magnetic symmetry is a vital factor to determine exotic topological phases. Here, Riberolles et al. demonstrate a helical antiferromagnetic order in EuIn2As2 which makes it a magnetic topological-crystalline axion insulator.

The full-waveform data is the core data of GaoFen-7 (GF-7) satellite laser altimeter, and evaluation of waveform data quality is an important step and premise for satellite laser altimetry and quality control. In this paper, the full waveform data quality assessment and analysis of GF-7 laser altimeter is implemented during the period of on-orbit experiment, and the real waveform data of many orbits is used to quantitatively describe the characteristic parameters of the transmitted waveform and the signal-to-noise ratio (SNR), and the result of two beam lasers is compared. The conclusion is validated that the GF-7 laser altimeter can obtain effective waveform data and the echo waveform availability of the experimental data is approximate 72.59%, moreover, the quality of beam 1 is slightly better than that of the beam 2. The laser temperature is an important indication of the quality of transmitted waveform according to the SNR changing. The good SNR value of the waveform and small footprint size will be helpful for the terrain information extraction and analysis, although the repetition frequency is low.

This paper entails a methodological novelty and builds upon prior research on a wavelets-based model for digital camera self-calibration. We introduce a new kernel function based on the compactly supported orthogonal third-order asymmetric Daubechies wavelet to correct systematic image distortion errors. Tests are done by using aerial images taken with a high-resolution metric digital aerial mapping camera. The quality of experimental results is evaluated by using reliable and high precision ground check points in the calibration field. For example, a four-fold block with this wavelet self-calibration model has the external accuracy of about 0.28 GSD (=ground sampling distance) in the horizontal direction, and about 0.43 GSD in the vertical direction, respectively, where 1GSD ≈ 4.6cm. The posterior standard deviations σ̂0 of unit weight are reduced from 0.37 pixel to 0.27 pixel. The residual vector lengths are also significantly reduced after our wavelet additional parameters are used. Experimental results support the proposal and demonstrate the applicability of this new model.

The increasing applications for location-based services (LBS) and real-time location system (RTLS) promote the development of indoor positioning and navigation technology. However, the positioning methods based on traditional Radio Frequency (RF) signals are difficult to improve the accuracy and sensitivity for rapid movement detection with a low latency parameter. In order to solve those problems, this paper adopted ultra-wideband (UWB) chips as the wireless communication technology and designed a method of rapid movement detection with low delay. The method consists of a topology of combined two way ranging (C-TWR), a schedule of time division multiple access (TDMA), an non-light-of-sight (NLOS) handling mechanism and an adaptive extended Kalman filter (A-EKF). To examine the low delay performance, accuracy and robustness of the system, a specific electro-displacement actuator with programmable speed is applied to provide precise ground truth for real speed and distance, and a system test platform consisting of four anchors and four tags provides information of specific situation. The results show that the system can locate the rapid moving pedestrian with a maximal speed of approximately 5 m s−1 in real-time with a positioning accuracy of less than 0.5 m. There are profound implications for further studies in the range of human wearable tags.

A 3-D unstructured-grid hydrodynamic model for the northern Gulf of Mexico was developed, with a hybrid s–z vertical grid and high-resolution horizontal grid for the main estuarine systems along the Texas–Louisiana coast. This model, based on the Semi-implicit Cross-scale Hydroscience Integrated System Model (SCHISM), is driven by the observed river discharge, reanalysis atmospheric forcing, and open boundary conditions from global HYCOM output. The model reproduces the temporal and spatial variation of observed water level, salinity, temperature, and current velocity in Galveston Bay and on the shelf. The validated model was applied to examine the remote influence of neighboring large rivers, specifically the Mississippi–Atchafalaya River (MAR) system, on salinity, stratification, vertical mixing, and longshore transport along the Texas coast. Numerical experiments reveal that the MAR discharge could significantly decrease the salinity and change the stratification and vertical mixing on the inner Texas shelf. It would take about 25 and 50 d for the MAR discharge to reach the mouth of Galveston Bay and Port Aransas, respectively. The influence of the MAR discharge is sensitive to the wind field. Winter wind constrains the MAR freshwater to form a narrow lower-salinity band against the shore from the Mississippi Delta all the way to the southwestern Texas coast, while summer wind reduces the downcoast longshore transport significantly, weakening the influence of the MAR discharge on surface salinity along Texas coast. However, summer wind causes a much stronger stratification on the Texas shelf, leading to a weaker vertical mixing. The decrease in salinity of up to 10 psu at the mouth of Galveston Bay due to the MAR discharge results in a decrease in horizontal density gradient, a decrease in the salt flux, and a weakened estuarine circulation and estuarine–ocean exchange. We highlight the flexibility of the model and its capability to simulate not only estuarine dynamics and shelf-wide transport, but also the interactions between them.

In the last few decades and in the near future CO2-induced ocean acidification is potentially a big threat to marine calcite-shelled animals (e.g. brachiopods, bivalves, corals and gastropods). Despite the great number of studies focusing on the effects of acidification on shell growth, metabolism, shell dissolution and shell repair, the consequences for biomineral formation remain poorly understood. Only a few studies have addressed the impact of ocean acidification on shell microstructure and geochemistry. In this study, a detailed microstructure and stable isotope geochemistry investigation was performed on nine adult brachiopod specimens of Magellania venosa (Dixon, 1789). These were grown in the natural environment as well as in controlled culturing experiments under different pH conditions (ranging from 7.35 to 8.15±0.05) over different time intervals (214 to 335 days). Details of shell microstructural features, such as thickness of the primary layer, density and size of endopunctae and morphology of the basic structural unit of the secondary layer were analysed using scanning electron microscopy. Stable isotope compositions (δ13C and δ18O) were tested from the secondary shell layer along shell ontogenetic increments in both dorsal and ventral valves. Based on our comprehensive dataset, we observed that, under low-pH conditions, M. venosa produced a more organic-rich shell with higher density of and larger endopunctae, and smaller secondary layer fibres. Also, increasingly negative δ13C and δ18O values are recorded by the shell produced during culturing and are related to the CO2 source in the culture set-up. Both the microstructural changes and the stable isotope results are similar to observations on brachiopods from the fossil record and strongly support the value of brachiopods as robust archives of proxies for studying ocean acidification events in the geologic past.

On the basis of introducing the SPH (Smooth Particle Hydrodynamics) simulation method, the key research problems were given solutions in this paper, which ere the spatial scale and temporal scale adapting to the GIS(Geographical Information System) application, the boundary condition equations combined with the underlying surface, and the kernel function and parameters applicable to dam-break flood simulation. In this regards, a calculation method of spatio-temporal process emulation with elaborate particles for dam-break flood was proposed. Moreover the spatio-temporal process was dynamic simulated by using GIS modelling and visualization. The results show that the method gets more information, objectiveness and real situations.

Spherical nanoindentation was performed at room temperature to characterize the time-dependent plasticity behavior of the single-phase CoCrFeMnNi high-entropy alloy (HEA). It was observed that incipient plasticity occurred after a period of waiting time in the apparent elastic regime. Through the experimental data, an activation energy ∼0.74 eV and an activation volume ∼1.54b3 (b = Burgers vector) were extracted for the delayed plasticity. Our results indicate that heterogeneous dislocation nucleation governs the delayed plasticity in the single-phase CoCrFeMnNi, and also provide quantitative insights into viscoplastic behavior and creep mechanisms in HEAs.

ABSTRACTThis study aimed at examining the effect of overfeeding on the activity of the mTOR pathway in the liver and muscle tissues of Gang geese. Eighty healthy male Gang geese were reared under the same feeding conditions, and were divided at 14 weeks of age into a control group and an overfed group. All birds were slaughtered after three weeks of over feeding. Gene expression and protein content of several genes involved in the mTOR pathway were evaluated. The results showed that the gene expression of mTOR, raptor, and rictor, and the protein contents of mTOR and PI3K were higher in liver, breast muscle, and leg muscle of the overfed group than that of control group. However, the S6K expression level was clearly lower in the liver of the overfed group than that of control group, and there was no evident difference in both breast muscle and leg muscle between the control group and the overfed group. These results suggest that overfeeding induces the activity of raptor, rictor, and mTOR, and that mTOR signaling pathway was closely linked with PI3K pathway in the evaluated geese.

In a pressure wave generator mainly consisting of a stator and a rotor with several valve blocks, pressure waves are generated by the continuous shear perturbation of fluids. In this paper, theory analysis of pressure wave generated in water hammer principle was conducted. Then a simplified CFD model of a pressure wave generator connecting the upstream and downstream pipes was established, and the grid and the time step independence tests were carried out. Generating process of controllable pressure waves in pipe flows was simulated, and the frequency and amplitude characteristics were obtained. The results suggest that pressure waves in upstream and downstream pipes have the similar shapes of approximate sinusoidal waveform and opposite phase. Pressure is inversely proportional to the first order derivative of x-velocity at a certain position, which is in good agreement with theoretical analysis; pressure wave amplitude increases with an increment of the rotational frequency of the rotor at the beginning of the pressure wave generator operation, but reaches the maximum amplitude in an optimal frequency when the generator is in stable operation, which means there exists a transition process for the generator. The critical frequency related to the first characteristics time can be applied to avoid the waveform distortion.

Sliding vane pressure exchanger (SVPE) is expected to be an efficient device which recovers pressure energy from liquid streams in seawater reverse osmosis (SWRO) system. In this work, a matching design of vane number and port location was proposed to eliminate the short circuit flow, reversed flow, liquid decompression and compression. The contact performance between the cylinder and vane was studied by the proposed vane dynamics model. Then, the vane dynamics model in conjunction with the energy loss model were used to evaluate the work transfer efficiency of SVPE. The critical condition of contact performance and the work transfer efficiency of SVPE were simulated. Finally, the influences of device parameters on the work transfer efficiency were discussed. The results suggest a careful selection of device parameters, such as rotational speed, vane thickness and vane length, is critical in order to improve the work transfer efficiency of SVPE.

Based on the thermal and membrane desalination technology, this study presents an analysis of an integrated single stage TVC-RO system. The hybrid system produces fresh water with an adjustable salinity in parallel operation. A steam ejector and a pressure exchanger are applied as the energy recovery devices. For comparison, a coupling system without energy recovery process is also modeled in the steady-state condition. System performance is evaluated by specific energy consumption and production ratio. The effects of several design parameters on system performance are investigated including boiling temperature, compression ratio, motive steam pressure, and target recovery rate. Results of the analysis indicate that the product salinity is adjustable in the TVC-RO system, and the system performance is largely dominated by system configurations and design parameters. To improve the system performance, the use of energy recovery device is necessary, and the membrane operation is recommended if the process is less demanding on product purity. A better performance can be obtained by increasing the target recovery rate of the RO membrane and decreasing compression ratio and motive steam pressure of the ejector. As the boiling temperature increases, one can expect that the production rate increases at a cost of a higher specific energy consumption.

Two utility based dynamic subcarrier allocation (DSA) algorithms: the max exponential utility (MEU) algorithm and the max weighted exponential utility (MWEU) algorithm are proposed for quality of service (QoS) guarantees in single carrier frequency division multiple access (SC-FDMA) system. With the objective of maximizing the system total utility, the two proposed DSA algorithms are designed based on a cross-layer manner so as to guarantee the diverse QoS requirements of real-time traffic. The proposed MEU algorithm exploits the property of the exponential utility function to provide higher allocation priority for the user in heavy traffic load. Furthermore, the MWEU algorithm is proposed as a kind of priority adjustable DSA scheduling by introducing the grading theory and the weight factor into the utility function. Simulation results indicate that the MEU algorithm is able to achieve outstanding average delay and system rate-sum capacity performance. And the MWEU algorithm can further improve the delay variance and delay violation probability performance by setting appropriate allocation weights. It is also concluded that the adaptive weight factor value of the MWEU algorithm can be derived according to the practical QoS requirements and average packets arrival rate.

The competitive price game model is used to analyze the spectrum sharing problem in the cognitive radio networks, and the spectrum sharing problem with the constraints of available spectrum resource from primary users is further discussed in this paper. The Rockafeller multiplier method is applied to deal with the constraints of available licensed spectrum resource, and the improved profits function is achieved, which can be used to measure the impact of shared spectrum price strategies on the system profit. However, in the competitive spectrum sharing problem of practical cognitive radio network, primary users have to determine price of the shared spectrum without the acknowledgement of the other primary user’s price strategies. Thus a fast gradient iterative calculation method of equilibrium price is proposed, only with acknowledgement of the price strategies of shared spectrum during last cycle. Through the adaptive iteration at the direction with largest gradient of improved profit function, the equilibrium price strategies can be achieved rapidly. It can also avoid the predefinition of adjustment factor according to the parameters of communication system in conventional linear iteration method. Simulation results show that the proposed competitive price spectrum sharing model can be applied in the cognitive radio networks with constraints of available licensed spectrum, and it has better convergence performance.

Melt spinning method has been widely applied for fabrication of Fe-based amorphous/nanocrystalline ribbons in industry. Compared with Fe-based amorphous/nanocrystalline alloys, Fe-6.5wt%Si high silicon steel is of low cost and has comparable excellent soft magnetic properties. Due to higher melting point and absence of supercooled liquid region, fabrication of Fe-6.5wt%Si ribbons is very hard and is only on lab scale. In this paper, we report that large scale fabrication of Fe-6.5wt%Si ribbons was successful and microstructures, ordered structures, and mechanical and soft magnetic properties of the ribbons were investigated. Due to rapid solidification rate, the ribbons were of ultrafine grains, and low degree of order and exhibited some extent of bending and tensile ductility. After heat treatment, excellent soft magnetic properties were obtained. Due to near-zero magnetostriction, the ribbons are promising to be used in electric devices with high frequencies where low noises are required.

Fe-6.5wt.%Si alloy is prepared in the form of continuous ribbons with 25 mm in width and 0.03 mm in thickness by using melt spinning technique. The ribbons are flexible and could be wounded into tapes. DC magnetic properties and core loss behaviors of the ribbons after heat treatment are investigated in this paper. The magnetic properties are compared with ribbons by cold rolling and CVD methods. The melt spinning ribbons exhibit much less core loss in the frequencies more than 10 kHz. The melt spinning ribbons are promising to be used for electric devices used in medium or higher frequencies.

We have developed a rapid, cost-effective, high-throughput readout for single nucleotide polymorphism (SNP) genotyping using flow cytometric analysis performed on a Luminex™ 100 flow cytometer. This robust technique employs a PCR-derived target DNA containing the SNP, a synthetic SNP-complementary ZipCode-bearing capture probe, a fluorescent reporter molecule, and a thermophilic DNA polymerase. An array of fluorescent microspheres, covalently coupled with complementary ZipCode sequences (cZipCodes), was hybridized to the reaction products and sequestered them for flow cytometric analysis. The single base chain extension (SBCE) reaction was used to assay 20 multiplexed SNPs for 633 patients in 96-well format. Comparison of the microsphere-based SBCE assay results to gel-based oligonucleotide ligation assay (OLA) results showed 99.3% agreement in genotype assignments. Substitution of direct-labeled R6G dideoxynucleotide with indirect-labeled phycoerythrin dideoxynucleotide enhanced signal five- to tenfold while maintaining low noise levels. A new assay based on allele-specific primer extension (ASPE) was validated on a set of 15 multiplexed SNPs for 96 patients. ASPE offers both the advantage of streamlining the SNP analysis protocol and the ability to perform multiplex SNP analysis on any mixture of allelic variants.

Replication protein A (RPA) is a ubiquitous eukaryotic single-stranded DNA (ssDNA) binding protein necessary for all aspects of DNA metabolism involving an ssDNA intermediate, including DNA replication, repair, recombination, DNA damage response and checkpoint activation, and telomere maintenance. The role of RPA in most of these reactions is to protect the ssDNA until it can be delivered to downstream enzymes. Therefore a crucial feature of RPA is that it must bind very tightly to ssDNA, but must also be easily displaced from ssDNA to allow other proteins to gain access to the substrate. Here we use total internal reflection fluorescence microscopy and nanofabricated DNA curtains to visualize the behavior of Saccharomyces cerevisiae RPA on individual strands of ssDNA in real-time. Our results show that RPA remains bound to ssDNA for long periods of time when free protein is absent from solution. In contrast, RPA rapidly dissociates from ssDNA when free RPA is present in solution allowing rapid exchange between the free and bound states. In addition, the S. cerevisiae DNA recombinase Rad51 and E. coli single-stranded binding protein (SSB) also promote removal of RPA from ssDNA. These results reveal an unanticipated exchange between bound and free RPA suggesting a binding mechanism that can confer exceptionally slow off rates, yet also enables rapid displacement through a direct exchange mechanism that is reliant upon the presence of free ssDNA-binding proteins in solution. Our results indicate that RPA undergoes constant microscopic dissociation under all conditions, but this is only manifested as macroscopic dissociation (i.e. exchange) when free proteins are present in solution, and this effect is due to mass action. We propose that the dissociation of RPA from ssDNA involves a partially dissociated intermediate, which exposes a small section of ssDNA allowing other proteins to access to the DNA.