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We here focus on the behavior of supernovae that technically explode in 1D (spherical symmetry). When simulated in 3D, however, the outcomes of representative progenitors of this class are quite different in almost all relevant quantities. In 3D, the explosion energies can be 2 to 10 times higher, and there are correspondingly large differences in the 56Ni yields. These differences between the 3D and 1D simulations reflect in part the relative delay to explosion of the latter and in the former the presence of protoneutron star convection that boosts the driving neutrino luminosities by as much as ∼50% at later times. In addition, we find that the ejecta in 3D models are more neutron-rich, resulting in significant weak r -process and 48Ca yields. Furthermore, we find that in 3D the core is an interesting, though subdominant, source of acoustic power. In summary, we find that though a model might be found theoretically to explode in 1D, one must perform supernova simulations in 3D to capture most of the associated observables. The differences between 1D and 3D models are just too large to ignore. [ABSTRACT FROM AUTHOR]

Crop roots selectively recruit certain microbial taxa that are essential for supporting their growth. Within the recruited microbes, some taxa are consistently enriched in the rhizosphere across various locations and crop genotypes, while others are unique to specific planting sites or genotypes. Whether these differentially enriched taxa are different in community composition and how they interact with nutrient cycling need further investigation. Here, we sampled bulk soil and the rhizosphere soil of five soybean varieties grown in Shijiazhuang and Xuzhou, categorized the rhizosphere-enriched microbes into shared, site-specific, and variety-specific taxa, and analyzed their correlation with the diazotrophic communities and microbial genes involved in nitrogen (N) cycling. The shared taxa were dominated by Actinobacteria and Thaumarchaeota, the site-specific taxa were dominated by Actinobacteria in Shijiazhuang and by Nitrospirae in Xuzhou, while the variety-specific taxa were more evenly distributed in several phyla and contained many rare operational taxonomic units (OTUs). The rhizosphere-enriched taxa correlated with most diazotroph orders negatively but with eight orders including Rhizobiales positively. Each group within the shared, site-specific, and variety-specific taxa negatively correlated with bacterial amoA and narG in Shijiazhuang and positively correlated with archaeal amoA in Xuzhou. These results revealed that the shared, site-specific, and variety-specific taxa are distinct in community compositions but similar in associations with rhizosphere N-cycling functions. They exhibited potential in regulating the soybean roots' selection for high-efficiency diazotrophs and the ammonia-oxidizing and denitrification processes. This study provides new insights into soybean rhizosphere-enriched microbes and their association with N cycling. Key points: • Soybean rhizosphere affected diazotroph community and enriched nifH, amoA, and nosZ. • Shared and site- and variety-specific taxa were dominated by different phyla. • Rhizosphere-enriched taxa were similarly associated with N-cycle functions. [ABSTRACT FROM AUTHOR]

In this paper, we analyze the neutrino-driven winds that emerge in 12 unprecedentedly long-duration 3D core-collapse supernova simulations done using the code F ornax. The 12 models cover progenitors with zero-age main-sequence mass between 9 and 60 solar masses. In all our models, we see transonic outflows that are at least 2 times as fast as the surrounding ejecta and that originate generically from a proto−neutron star surface atmosphere that is turbulent and rotating. We find that winds are common features of 3D simulations, even if there is anisotropic early infall. We find that the basic dynamical properties of 3D winds behave qualitatively similarly to those inferred in the past using simpler 1D models, but that the shape of the emergent wind can be deformed, very aspherical, and channeled by its environment. The thermal properties of winds for less massive progenitors very approximately recapitulate the 1D stationary solutions, while for more massive progenitors they deviate significantly owing to aspherical accretion. The Y e temporal evolution in winds is stochastic, and there can be some neutron-rich phases. Though no strong r -process is seen in any model, a weak r -process can be produced, and isotopes up to 90Zr are synthesized in some models. Finally, we find that there is at most a few percent of a solar mass in the integrated wind component, while the energy carried by the wind itself can be as much as 10%–20% of the total explosion energy. [ABSTRACT FROM AUTHOR]

Background: Paenibacillus polymyxa WLY78 is a Gram-positive, endospore-forming and N2-fixing bacterium. Our previous study has demonstrated that GlnR acts as both an activator and a repressor to regulate the transcription of the nif (nitrogen fixation) operon (nifBHDKENXhesAnifV) according to nitrogen availability, which is achieved by binding to the two GlnR-binding sites located in the nif promoter region. However, further study on the GlnR-mediated global regulation in this bacterium is still needed. Results: In this study, global identification of the genes directly under GlnR control is determined by using chromatin immunoprecipitation-quantitative PCR (ChIP-qPCR) and electrophoretic mobility shift assays (EMSA). Our results reveal that GlnR directly regulates the transcription of 17 genes/operons, including a nif operon, 14 nitrogen metabolism genes/operons (glnRA, amtBglnK, glnA1, glnK1, glnQHMP, nasA, nasD1, nasD2EF, gcvH, ansZ, pucR, oppABC, appABCDF and dppABC) and 2 carbon metabolism genes (ldh3 and maeA1). Except for the glnRA and nif operon, the other 15 genes/operons are newly identified targets of GlnR. Furthermore, genome-wide transcription analyses reveal that GlnR not only directly regulates the expression of these 17 genes/operons, but also indirectly controls the expression of some other genes/operons involved in nitrogen fixation and the metabolisms of nitrogen and carbon. Conclusion: This study provides a GlnR-mediated regulation network of nitrogen fixation and the metabolisms of nitrogen and carbon. [ABSTRACT FROM AUTHOR]

The two-moment method is widely used to approximate the full neutrino transport equation in core-collapse supernova (CCSN) simulations, and different closures lead to subtle differences in the simulation results. In this paper, we compare the effects of closure choices on various physical quantities in 1D and 2D time-dependent CCSN simulations with our multigroup radiation hydrodynamics code F ornax. We find that choices of the third-order closure relations influence the time-dependent simulations only slightly. Choices of the second-order closure relation have larger consequences than choices of the third-order closure, but these are still small compared to the remaining variations due to ambiguities in some physical inputs such as the nuclear equation of state. We also find that deviations in Eddington factors are not monotonically related to deviations in physical quantities, which means that simply comparing the Eddington factors does not inform one concerning which closure is better. [ABSTRACT FROM AUTHOR]

Calibrating with detailed 2D core-collapse supernova (CCSN) simulations, we derive a simple CCSN explosion condition based solely upon the terminal density profiles of state-of-the-art stellar evolution calculations of the progenitor massive stars. This condition captures the vast majority of the behaviour of the one hundred 2D state-of-the-art models we performed to gauge its usefulness. The goal is to predict, without resort to detailed simulation, the explodability of a given massive star. We find that the simple maximum fractional ram pressure jump discriminant we define works well ∼90 per cent of the time and we speculate on the origin of the few false positives and false negatives we witness. The maximum ram pressure jump generally occurs at the time of accretion of the silicon/oxygen interface, but not always. Our results depend upon the fidelity with which the current implementation of our code F  ornax adheres to Nature and issues concerning the neutrino–matter interaction, the nuclear equation of state, the possible effects of neutrino oscillations, grid resolution, the possible role of rotation and magnetic fields, and the accuracy of the numerical algorithms employed remain to be resolved. Nevertheless, the explodability condition we obtain is simple to implement, shows promise that it might be further generalized while still employing data from only the unstable Chandrasekhar progenitors, and is a more credible and robust simple explosion predictor than can currently be found in the literature. [ABSTRACT FROM AUTHOR]

We propose a polarization-insensitive σ -shaped coupled optoelectronic oscillator (σ -COEO) based on an active mode-locking technique and demonstrate that it can generate microwave pulse trains with tunable repetition frequencies. Mode-locking in the time domain is achieved by injecting an external microwave signal with an integral multiple of the frequency of the COEO's free spectral range, which is used as a bias for the modulator to control the loss in the COEO cavity. In addition, the σ -shaped fiber ring structure is cleverly utilized in COEO to ensure the high Q value of the system while eliminating the polarization perturbation caused by long fibers. The experiment demonstrates that, under the current scheme, the phase noise of various higher order harmonics generated by different carriers is better than −114 dBc/Hz at a frequency offset of 10 kHz. This is a positive finding as it effectively suppresses the phase noise deterioration caused by higher order harmonics. The potential applications of the proposed σ -COEO are significant, spanning fields such as metrology, hybrid communications, and radar systems. • The proposed COEO an directly adjustable center frequency and time duration of pulsed microwave signal, breaking the limitation that current COEO research is still conducted in the frequency domain. • The σ -shaped fiber ring structure is skillfully utilized in COEO to limit the spurious noise, the harmonic mode locking of different orders can be easily realized, and the phase noise of the system does not deteriorate significantly. • The value and potential of microwave pulses generated by COEO for practical applications in radar communications are detailed. [ABSTRACT FROM AUTHOR]

An underwater glider (UG) is a buoyancy-propelled and fixed-wing vehicle with attitude controlled completely by means of internal mass redistribution. Since the highly nonlinear and cross-coupled system dynamics, uncertain hydrodynamic parameters and uncertain internal dynamics, model-based control is hardly possible to employ in motion control of UGs. This paper presents a model-free motion control framework of UGs which named inverse model control (IMC). It takes the desired velocity as input, and outputs the control variables of directly and enables the glider to complete the behaviors of motion. Besides, we propose a novel method to represent the framework based on model-free reinforcement learning, which named heterogeneous agent asynchronous policy gradient (HAAPG). It has achieved high-precision motion control and could intermittently adjust the movable mass block rotation amount to correct the deviation caused by currents, which is energy-saving. To verify the effectiveness of the IMC framework and the superiority of HAPPG algorithm, the dynamic model of underwater glider is established and a series of motion simulation scenarios are established. In addition, we conduct sea trials and deploy our IMC framework into actual underwater gliders to perform tasks and achieved satisfactory performance. • A general model-free motion control framework for underwater glider is proposed. • Presented a novel reinforcement learning method to further improve control accuracy. • The proposed framework have completed motion control tasks in simulation results. • Sea trials are conducted to validate the control framework in real world. [ABSTRACT FROM AUTHOR]

This paper presents a dynamic segmentation and weighted comprehensive matching algorithm based on neural networks for cross-media piano performance audio recognition and retrieval. The 3D convolutional neural network process is separated to compress the network parameters and improve the computational speed. Skip connection and layer-wise learning rate solve the problem that the separated network is challenging to train. The piano performance audio recognition is facilitated by shuffle operation. In pattern recognition, music retrieval algorithms are gaining more and more attention due to their ease of implementation and efficiency. However, the problems of imprecise dynamic note segmentation and inconsistent matching templates directly affect the accuracy of the MIR algorithm. We propose a dynamic threshold-based segmentation and weighted comprehensive matching algorithm to solve these problems. The amplitude difference step is dynamically set, and the notes are segmented according to the changing threshold to improve the accuracy of note segmentation. A standard score frequency is used to transform the pitch template to achieve input normalization to enhance the accuracy of matching. Direct matching and DTW matching are fused to improve the adaptability and robustness of the algorithm. Finally, the effectiveness of the method is experimentally demonstrated. This paper implements the data collection and processing, audio recognition, and retrieval algorithm for cross-media piano performance big data through three main modules: the collection, processing, and storage module of cross-media piano performance big data, the building module of audio recognition of cross-media piano performance big data, and the dynamic precision module of cross-media piano performance big data. [ABSTRACT FROM AUTHOR]

Objective. Traditional Chinese medicine (TCM) has been used to treat Parkinson's disease (PD), but the efficacy is still not clear. The aim of this study was to evaluate the effect of the integrated Chinese and Western medicine (ICWM) for PD through a meta-analysis. Methods. We searched randomized controlled trials comparing integrated Chinese and Western medicine (ICWM) versus conventional Western medicine (CWM) for Parkinson's disease. Data were extracted from eligible studies. We sought to evaluate pretreatment and posttreatment symptoms of PD patients and their quality of life and reduce adverse reactions. The results were expressed as risk ratio (RR) and mean difference (MD) with accompanying 95% confidence intervals. Results. Twenty-three studies were included in this study with a total of 1769 patients. The pooled results revealed that ICWM significantly improved the UPDRS score than CWM, the MD of UPDRS-I, II, III, and IV was -1.05 (95% CI: -1.42 to -0.69, P < 0.00001), -2.55 (95% CI: -3.19 to -1.90, P < 0.00001), -3.64 (95% CI: -4.69 to -2.60, P < 0.00001), and -0.61 (95% CI: -0.96 to -0.27, P = 0.0004), respectively, and ICWM also had a better score of PDQ-39 (MD = − 8.71 , 95% CI: -13.52 to -3.90, P = 0.0004) and MoCA scores (MD = 3.35 , 95% CI: 1.65 to 5.04, P = 0.0001) compared with CWM. ICWM had certain advantages in terms of effective rate (RR = 1.27 , 95% CI: 1.18 to 1.37, P < 0.00001) and adverse reactions (RR = 0.21 , 95% CI: 0.13 to 0.36, P < 0.00001). Conclusion. Our research supported that ICWM had important health benefits for patients with PD and can effectively improve the symptoms of PD patients and their quality of life and reduce adverse reactions. Due to the lower quality of the included studies, large sample and multicenter randomized control test should be performed to verify our conclusions. [ABSTRACT FROM AUTHOR]

By analyzing the recorded operation data of a nuclear power plant (NPP), its results can serve the fault detection or operation experience feedback. Data missing exists in the recorded operation data. It may lower the data quality and affect the accuracy of the analysis results. In order to improve the data quality, two parts of researches are carried on. Firstly, to locate the missing data accurately the detecting algorithm for missing data of the NPP operation parameters based on wavelet analysis. Different judging basis is proposed for discrete and continuous missing respectively. Then, the filling method based on the hot deck algorithm are studied. As the dynamic properties of the parameters are closely related to the operating state of NPP, the similarity of the operation parameter vectors are formed to express the similarity of the operating states, so as to fulfill the requirements of the hot deck algorithm. To improve the accuracy of the measuring results, taken the differences between the characteristics of the analog parameters and the switch parameters into consideration, the similarity measurements using Mahalanobis distance for the analog parameter vectors and the matching measure for the switch parameter vectors are studied respectively. Finally, the operation data is taken to build the experiment data set for the algorithm verification. The results shows that the designed algorithm performs much better than the mean interpolation method and LSTM. [ABSTRACT FROM AUTHOR]

In this paper, a shear stiffness model for corrugated-core sandwich structures is proposed. The bonding area is discussed independently. The core is thought to be hinged on the skins with torsional stiffness. The analytical model was verified by FEM solution. Compared with the previous studies, the new model can predict the valley point of the shear stiffness at which the relationship between the shear stiffness and the angle of the core changes from negative correlation to positive correlation. The valley point increases when the core becomes stronger. For the structure with a angle of the core smaller than counterpart for the valley point, the existing analytical formulations may significantly underestimate the shear stiffness of the structure with strong skins. The results obtained by some previous models may be only 10 persent of that of the present model, which is supported by the FEM model. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine that low-intensity pulsed ultrasound (LIPUS) at an intensity of 140 mW/cm2 promotes functional and histologic improvements in sciatic nerve crush injury in a rat model and to investigate changes over time in relevant growth factors and receptors, exploring the mechanism of LIPUS in the recovery process after injury. Toe angle in the toe-off phase, regenerative axonal length, myelinated nerve fiber density, diameter of myelinated nerve fiber, axon diameter and myelin sheath thickness were significantly higher in the LIPUS group than in the sham group. Gene and protein expression of brain-derived neurotrophic factor (BDNF) was upregulated in the LIPUS group. In conclusion, LIPUS contributed to rapid functional and histologic improvement and upregulated BDNF expression after sciatic nerve crush injury in rats. [ABSTRACT FROM AUTHOR]

Traditional chemical processes currently produce tar as a by-product with low efficiency. This paper proposes a novel tar chemical looping reforming (t-CLR) process based on reactive force field (ReaxFF) reaction kinetics investigation to enhance its utilization efficiency. Firstly, the t-CLR process is initially established to determine the optimum operating conditions. Through ReaxFF molecular dynamics (ReaxFF-MD) simulations conducted under above conditions, the activation energies of the fuel reactor, steam reactor, and air reactor are determined to be 63.25 kJ/kmol, 107.85 kJ/kmol, and 159.53 kJ/kmol respectively. By implementing micro-dynamic parameters filling, oxygen carrier recovery, and heat integration, the optimal t-CLR process achieves a 97.60 % recovery rate of the oxygen carrier and reduces external utility consumption by 71.39 %. The comprehensive framework with macro and micro dimensions is established based on the above studies to promote the cleaner production of traditional processes. Finally, the utilization efficiency of tar is efficiently improved through t-CLR technology, which allows for an adjustable C/H ratio in syngas. The t-CLR technology can be applied to the chemical and energy industries by adding value to by-products and optimizing energy utilization. Overall, this work provides important guidance for process intensification, energy conservation, environmental protection, and waste utilization. The study further promotes the development of industrial production in a cleaner and more efficient direction. [Display omitted] • t-CLR technology is proposed to improve tar utilization efficiency. • Reaction kinetics equations of t-CLR is obtained by ReaxFF-MD simulation. • Multi-level optimization of t-CLR improves utilization of resources and energy. [ABSTRACT FROM AUTHOR]

Based on the composite interference structure, fiber optic multiparameter sensors can be constructed, however, this type of sensor has two bottlenecks, which are difficult to fabricate and the parameters interfere with each other. This paper proposes to simultaneously measure force, temperature, and salinity using a compact sensor with minimal signal crosstalk. The sensor structure consists of three cascaded Mach-Zehnder interferometers (MZI). The use of different diameter fiber cores fused together creates a dumbbell Stepped taper-like structure, which ensures that more higher order modes are excited while maintaining the mechanical integrity of the sensor. By creating detecting regions of various sizes, signal interference between parameters is reduced. Theoretical and experimental findings demonstrate that sensors with the dumbbell structure provide a good foundation for three-parameter sensing. and its force, temperature, and salinity sensitivity can reach −2593 dB/N, 53 pm/°C and −145.4nm/RIU. The two bottlenecks mentioned above are effectively resolved by the proposed dumbbell stepped sensor, which may also be applied to multi-parameter measurements for structural health monitoring. • The sensor is capable of multi-parameter sensing with low signal crosstalk. • The sensor assembly consists of three cascaded Mach-Zehnder interferometers with stepped dumbbell cores. • The force, temperature, and salinity sensors' sensitivity values are −2593 dB/N, 53 pm/°C, and −145.4 nm/RIU, respectively. • Higher-order modes are stimulated by a dumbbell-stepped fiber core structure. [ABSTRACT FROM AUTHOR]

Machinery agriculture has increased crop yield but induced soil compaction worldwide in the last decades. The crop yield increase is partly attributed to high-yielding crop breeding, but the effects of emerging soil compaction on the selection of root system traits and its impact on yield increase remain unclear. The objectives of this study were 1) to identify the effects of soil compaction on grain yield and root system architecture and rhizosheath soil traits of soybean (Glycine max (L.) Merr.) at the full-bloom stage, 2) to understand whether and how the development of soil compaction affected the selection of merit root and rhizosheath soil traits through crop breeding and contributed to soybean grain yield increase. Thirty-four most popular soybean cultivars released before and after the wide use of agricultural machinery in the North China Plain were grown in the fields without (NOM) and with (COM) applied soil compaction in 2017 and 2018. The phenotypes of root system, including rhizosheath soil, of soybean, were separated by soil compaction and cultivar release period, confirming the development of soil compaction and its impacts on the co-development of rhizosheaths with the root system of soybean. The correlation with the year of release of the cultivar demonstrated that 21 out of the 24 measured traits were selected by crop breeding. Multivariate analysis of the variance demonstrated that the selection of thinner hypocotyl, more root tips, and denser rhizosheath soil were relevant to the soil compaction development. The selection of shorter plant height, larger root biomass and area, thinner root tip, thicker taproot, and rhizosheath soil mass were likely relevant to the experimental year factor caused by drought or its associated change in nutrient availability. Most of the selected traits increased the resistance or the resilience to soil compaction and nine of them correlated with the grain yield of cultivars released at different periods. These results for the first time suggested that crop breeding increased grain yield partly by increasing the resistance and resilience to soil compaction. Soil compaction could be considered in a future breeding program design to increase crop breeding efficiency by selecting resistant and resilient root traits. • Soybean breeding increased yield, root biomass, rhizosheath soil mass and RSA traits. • Soil compaction affected the selection of phenotype and some properties of root system. • Rhizosheath soil was co-developed with root system and selected due to soil compaction. • Thinner hypocotyl, more root tips, and denser rhizosheath were selected under soil compaction. • Increased resilience and resistance of root system to soil compaction contributed to grain yield. [ABSTRACT FROM AUTHOR]

The graded lattice structures have advantages in optimizing structure. In this paper, a parametric modeling method of graded lattice structure is proposed. The continuum damage model is used to evaluate the failure load of the structures. In this paper, two types of graded lattice structure are built by parametric modeling method: the cell-size-changed graded lattice structure (the densities of the structures are constant) and the bar-width-changed graded lattice structure (the masses of the structures are constant). The failure loads of the structures under three-point bending load are investigated. The results show that the smaller middle cell improves the bending failure load of the cell-size-changed graded lattice structures up to 52%, and the wider sandwich bar in the middle of the structure improves the bending failure load of the Bar-width-changed graded lattice structures up to 31%. Meanwhile, the graded parameter of the structures will influence the failure mode of the structures. [ABSTRACT FROM AUTHOR]

Background: Therapeutic ultrasound (US) is a promising physical therapy modality for peripheral nerve regeneration. However, it is necessary to identify the most effective US parameters and clarify the underlying mechanisms before its clinical application. The intensity of US is one of the most important parameters. However, the optimum intensity for the promotion of peripheral nerve regeneration has yet to be determined. Objectives: To identify the optimum intensity of US necessary for the promotion of peripheral nerve regeneration after crush injuries in rats and to clarify the underlying mechanisms of US by mRNA expression analysis. Methods: We inflicted sciatic nerve crush injuries on adult Lewis rats and performed ultrasound irradiation using 4 different US intensities: 0 (sham stimulation), 30, 140, and 250 mW/cm2 with frequency (5 days/week) and duration (5 min/day). We evaluated peripheral nerve regeneration by quantitative real-time PCR one week after injury. Histomorphometric analyses and motor function analysis were evaluated 3 weeks after injury. Results: US stimulation enhanced re-myelination as well as sprouting of axons, especially at an intensity of 140 mW/cm2. mRNA expression revealed that US suppressed the expression of the inflammatory cytokines TNF and IL-6 and the axonal growth inhibitors SEMA3A and GSK3β. Conclusions: An intensity of 140 mW/cm2 was optimal to support regeneration of the sciatic nerve after a crush injury in rats by, in part, the suppression of pro-inflammatory and nerve growth inhibitor gene expression. [ABSTRACT FROM AUTHOR]

Image quality assessment (IQA) is a meaningful research topic to meet the increasing demand of high‐quality image. The degradation of image quality will cause changes in image structural information. Meanwhile, human visual system is sensitive to changes in structural information. This finding motivates us to utilise structural information for proposing IQA method which is consistent with human visual perception. Recently, IQA methods are mainly focused on individual image type, e.g. natural image or screen content image (SCI), thus, the authors proposed a novel no‐reference IQA method which can be suitable for both natural image and SCI. The proposed method is based on structural information analysis. For each image, they first obtain the grey‐scale fluctuation maps (GFMs) in four detection directions. After that, the grey‐scale fluctuation direction map (GFD) of certain image can be acquired via its GFMs. Based on the GFMs and GFD, the structural features of each image are extracted, and then collected and transformed to feature vectors. Subsequently, the IQA model is trained by support vector regression. The experimental results on the public databases demonstrate the proposed method can predict image quality accurately for both natural image and SCI, and the performance is competitive with prevalent methods. [ABSTRACT FROM AUTHOR]

We experimentally demonstrate a high signal-to-noise ratio (SNR) partially coherent beam (PCB) source based on wide-spectrum produced by a filtered supercontinuum (SC) which can generate from a segment of highly nonlinear fiber (HNLF) pumped by a picosecond fiber laser. The SNR of PCB source can improve from 12.43 dB to 22.45 dB by filtering out amplified spontaneous emission (ASE) noise of erbium-doped fiber amplifier (EDFA) and using lower power pumped HNLF. We also conduct a 4 Gbit/s transmission experiment using the high SNR PCB source in 1km simulated atmospheric turbulent channel. The characteristics of scintillation indexes (SIs), eye patterns, SNRs and bit error rates (BER) based on CB source and PCB sources after turbulent channel are analyzed. In Δ T = 240 ° C , atmospheric turbulent channel, the SI of the CB link can reduce by 31% by using PCB source. The SNR of PCB source is 8.15 dB higher than the 5.20 dB of the CB source, and the sensitivity of the PCB source has a 2.9 dB improvement compared with the CB source. The PCB source possess high SNR and turbulence resistance, which can improve the performance of free space data transmission. [ABSTRACT FROM AUTHOR]

We demonstrate the all-optical wavelength conversion of short pulse signals at 2-μm using MXene-assisted microfiber. The process involves an actively mode-locked thulium-holmium co-doped fiber laser, which is synchronously modulated by a digital signal and coupled with continuous light for the conversion process. The converted light is generated via four-wave mixing (FWM) with in the MXene-assisted microfiber. The conversion efficiency reaches −38.98 dB. For a wavelength tuning range of 6.08 nm–1.04 nm, the conversion efficiency is increased by 10.44 dB. The wavelength conversion efficiency fluctuation during 130 min is only 0.512 dB. The converter enables the successful transmission of 489 Mb/s data carried by the converted light. The results show that the MXene-assisted microfiber carrier wavelength converter has a high conversion efficiency and excellent stability. This study aligns with the development trend of all-optical wavelength conversion and explores the characteristics of highly nonlinear optical materials. The utilization of MXene-assisted microfiber enables significant advancements in all-optical wavelength conversion, particularly in the context of processing 2-μm short data pulse signals for nonlinear optics applications. • The MXene-assisted microfiber nonlinear waveguide to realize all-optical wavelength conversion via four-wave mixing. • The MXene wavelength converter matches the digital signal of an actively mode-locked thulium-holmium co-doped fiber laser with the continuous light, and performs synchronous modulation to successfully convert the signal to adjacent wavelengths. • The MXene microfiber wavelength converter has laid a solid foundation for the advancement of 2-μm fiber communication systems. [ABSTRACT FROM AUTHOR]

Security is crucial in wireless sensor networks (WSNs) since a growing variety of applications require strict security. Cluster-based architecture has an enhancement in the system performance of WSNs. This article presents a trust enhancement scheme for cluster-based WSNs, where network time is divided into multiple rounds. Each round contains a setup phase and a steady-state phase. In the setup phase, clusters are formed and mutual trusted relationships between cluster nodes are established through two proposed authentication protocols called SET-μTESLA (Setup μTESLA) and SET-SCHNORR (Setup SCHNORR). SET-μTESLA uses the authenticated broadcast μTESLA scheme and reduces the iterations of hash function to improve the energy efficiency, while SET-SCHNORR applies a lightweight signature SCHNORR scheme. In the steady-state phase, collected environmental or physical data are transmitted through the proposed STEADY-μTESLA protocol (Steady-state μTESLA), which guarantees the data credibility. The analysis demonstrates that the security scheme does well in resisting such attacks as data confidentiality attacks, data integrity attacks and compromise node attacks. In addition, the results of calculations and simulations show that the proposed scheme performs better than the existing security protocols in terms of communication overhead and energy consumption. [ABSTRACT FROM AUTHOR]

Highlights • In this paper, a narrow band filter is firstly used to narrow the spectrum in order to increase repetition-rate of harmonic mode-locking (HML) fiber laser. • With 3-dB spectral bandwidth of 0.2 nm, maximum repetition-rate and pulse width of the output harmonic mode-locking pulse are 10.3 GHz (2040 orders) and 47.7 ps, respectively, and the side and mode suppression ratio (SMSR) is 43 dB. • In addition, the laser center wavelength can be tuned from 1882 nm to 1925 nm by adjusting the filter. Abstract We propose and demonstrate a high repetition-rate passively mode-locking Tm-doped fiber laser. Mode-locking operation is achieved by using a conventional nonlinear polarization rotation (NPR) structure. Fundamental frequency soliton laser is obtained with the repetition-rate of 5.05 MHz and the pulse width of 54.7 ps. 3-dB bandwidth and signal and noise ratio (SNR) are 3.1 nm and 53.03 dB, respectively. In order to improve repetition-rate of the mode-locking pulse, a narrow band filter is adopted. In this case, maximum repetition-rate of the output pulse can be up to 7.75 GHz (1534 orders). Pulse width and 3-dB bandwidth of mode-locking laser are compressed to 67.2 ps and 0.2 nm, respectively, and SNR is 19.71 dB. In addition, the laser center wavelength can be tuned from 1882 nm to 1925 nm by adjusting the filter. [ABSTRACT FROM AUTHOR]

A fog monitor, hotplate total precipitation sensor, weather identifier and visibility sensor, ultrasonic wind speed meter, an icing gradient observation frame, and an automated weather station were involved in the observations at the Lushan Meteorological Bureau of Jiangxi Province, China. In this study, for the icing process under a cold surge from 20-25 January 2016, the duration, frequency, and spectrum distribution of agglomerate fog were analyzed. The effects of rain, snow, and supercooled fog on icing growth were studied and the icing and meteorological conditions at two heights (10 m and 1.5 m) were compared. There were 218 agglomerate fogs in this icing process, of which agglomerate fogs with durations less than and greater than 10 min accounted for 91.3% and 8.7%, respectively. The average time interval was 10.3 min. The fog droplet number concentration for sizes 2-15 μm and 30-50 μm increased during rainfall, and that for 2-27 μm decreased during snowfall. Icing grew rapidly (1.3 mm h−1) in the freezing rain phase but slowly (0.1 mm h−1) during the dry snow phase. Intensive supercooled fog, lower temperatures and increased wind speed all favored icing growth during dry snow (0.5 mm h−1). There were significant differences in the thickness, duration, density, and growth mechanism of icing at the heights of 10 m and 1.5 m. Differences in temperature and wind speed between the two heights were the main reasons for the differences in icing conditions, which indicated that icing was strongly affected by height. [ABSTRACT FROM AUTHOR]

Elucidating whether there is a correlation between biomechanical functions and histomorphometric data in the rat sciatic nerve crush injury model would contribute to an accurate evaluation of the regeneration state without sacrificing animals. The gold standard for functional evaluation is the sciatic functional index (SFI) despite there being intrinsic shortcomings. Kinematic analysis is considered a reliable and sensitive approach for functional evaluation, most commonly assessed as ankle angle at various phases of a gait cycle. Studies utilizing the toe angle for functional evaluation are scarce, and changes in the toe angle following surgery remain unknown. The present study assessed correlations of ankle angle, toe angle and SFI with histomorphometric data, aiming to determine which parameters most accurately reflect changes in histomorphometric data over time. Six Lewis rats were designated as the control group. 30 animals received surgery, six of them were randomly selected on the first, second, third, fourth, and sixth week after surgery for measurements of ankle and toe angles in the “toe-off” phase, and for evaluation of SFI. Histomorphometric analysis were also performed, to determine the number of myelinated nerve fibers, diameters of myelinated nerve fibers, axon diameters, and myelin sheath thicknesses. Furthermore, we investigated changes in ankle angle, toe angle, SFI, and histomorphometric data over time, as well as correlations between ankle angle, toe angle, and SFI with histomorphometric data. The results revealed that changes in SFI, ankle angle, and toe angle highly correlate with histomorphometric data in the rat sciatic nerve crush injury model. Toe angle reflected changes in histomorphometric data with time more precisely than ankle angle or SFI did, and ankle angle was a better prognostic parameter than SFI. [ABSTRACT FROM AUTHOR]

Many functions have been proposed to describe the response of root water uptake to water and/or salinity stresses. In practice, choosing a reliable stress response function is challenging, particularly when water and salinity stresses occur simultaneously. To explore and quantify the effects of soil water and salinity conditions, separately and combined, on root water uptake, two experiments culturing winter wheat in artificial climate chambers were conducted with various water and salinity levels. As the key index, plant water status was evaluated by: a) considering the relative position of water and salinity to roots; b) rectifying estimation of potential transpiration for stressed plants; c) excluding data during recovery periods dominated by the hysteresis process of historical stress; and d) quantifying the interaction between water and salinity stresses. Including only one fitting parameter and two water or salinity thresholds with clear physical meaning and available recommendations, concave-convex function could quantify the effects of water or salinity stress more accurately than the others, leading to more reliable estimation of relative transpiration rate (RMSE < 0.07, R 2 > 0.91, MAE < 0.24). Under combined water-salinity stress conditions, neither an additive nor multiplicative approach was able to describe the interaction accurately. In addition to cumulative effect, by quantifying cross-adaptation effect with an exponential function, the multiplicative concave-convex functions significantly improved the estimation of relative transpiration rate for water- and salinity-stressed plants (RMS E < 0.08, R 2 > 0.72, MAE < 0.28). Nevertheless, mechanisms underlying the interaction between water and salinity stresses are still unclear and should be further investigated. To avoid the hysteresis effect of historical stress, excluding data during recovery periods was helpful, but its quantitative characterization is also necessary for accurate simulation of root water uptake and should be further studied. • Improved method to screen soil water and salinity stress response functions. • Concave-convex soil water and salinity stress response functions are superior. • Cross-adaptation effect between water and salinity stresses was quantified. • Multiplicative approach was improved to quantify combined water and salinity stress. [ABSTRACT FROM AUTHOR]

Ammonia is a major signal that regulates nitrogen fixation in most diazotrophs. Regulation of nitrogen fixation by ammonia in the Gram-negative diazotrophs is well-characterized. In these bacteria, this regulation occurs mainly at the level of nif (nitrogen fixation) gene transcription, which requires a nif-specific activator, NifA. Although Gram-positive and diazotrophic Paenibacilli have been extensively used as a bacterial fertilizer in agriculture, how nitrogen fixation is regulated in response to nitrogen availability in these bacteria remains unclear. An indigenous GlnR and GlnR/TnrA-binding sites in the promoter region of the nif cluster are conserved in these strains, indicating the role of GlnR as a regulator of nitrogen fixation. In this study, we for the first time reveal that GlnR of Paenibacillus polymyxa WLY78 is essentially required for nif gene transcription under nitrogen limitation, whereas both GlnR and glutamine synthetase (GS) encoded by glnA within glnRA operon are required for repressing nif expression under excess nitrogen. Dimerization of GlnR is necessary for binding of GlnR to DNA. GlnR in P. polymyxa WLY78 exists in a mixture of dimers and monomers. The C-terminal region of GlnR monomer is an autoinhibitory domain that prevents GlnR from binding DNA. Two GlnR-biding sites flank the -35/-10 regions of the nif promoter of the nif operon (nifBHDKENXhesAnifV). The GlnR-binding site Ⅰ (located upstream of -35/-10 regions of the nif promoter) is specially required for activating nif transcription, while GlnR-binding siteⅡ (located downstream of -35/-10 regions of the nif promoter) is for repressing nif expression. Under nitrogen limitation, GlnR dimer binds to GlnR-binding siteⅠ in a weak and transient association way and then activates nif transcription. During excess nitrogen, glutamine binds to and feedback inhibits GS by forming the complex FBI-GS. The FBI-GS interacts with the C-terminal domain of GlnR and stabilizes the binding affinity of GlnR to GlnR-binding site Ⅱ and thus represses nif transcription. [ABSTRACT FROM AUTHOR]

This paper studies the free vibration of an axially functionally graded beam spinning with constant angular speed about its longitudinal axis. Material properties of the beam are assumed to be varied continuously in the axial direction according to a power law. Its whirling frequencies, critical speeds, and mode shapes are obtained in order to investigate the influences of axially functionally graded material (FGM). Spinning Timoshenko beam model is employed to incorporate the effects of transverse shear, rotational inertia, and gyroscopic motion. A spectral-Tchebychev method is employed to derive the discrete governing equation and to solve the dynamic characteristics of the beam. Results show that the axially FGM has significant influences on the whirling frequencies, critical speeds, and mode shapes. But these influences depend on boundary condition, whirling mode, and slenderness ratio. For cantilever beams, by choosing appropriate material gradient index, higher whirling frequencies and critical speeds, compared to those of homogeneous beams, can be obtained. However, the superiority of axially FGM can’t be observed in beams with clamped-clamped, clamped-pinned, and pinned-pinned boundary conditions. Their critical speeds are smaller than those of one corresponding homogeneous beam. [ABSTRACT FROM AUTHOR]

Excitation design is one of the important contents in the identification of inertia parameters and the form of excitation has a great influence on the identification result. This paper presents a new method to design and calculate the optimal excitation. Firstly for a spacecraft equipped with momentum wheels, the identification problem is established based on conversation of angular momentum and an inverse operating. A performance index which is similar to but not the condition number is first defined as the benchmark for designing the optimal excitation. Because the performance index only depends on performances of the actuator, such as the angular momentum of the wheel, a simple direct-search method is applied to calculate the optimal excitation for the case without terminal angular velocity constraints and a two-step direct-search method for the case with terminal angular velocity constraints. While the initial angular momentum of spacecraft system is considered, the optimal excitation is obtained based on the difference of two successive measurements. Finally, the optimal excitation for a spacecraft using thrusters is designed according to the same design process. Simulation results show that the calculated optimal excitation has the good performance index and can produce accurate identification results even when some perturbations are considered. [ABSTRACT FROM AUTHOR]

We have simulated the collapse and evolution of the core of a solar-metallicity 40 M ⊙ star and find that it explodes vigorously by the neutrino mechanism, despite its very high "compactness." Within ∼1.5 s of explosion, a black hole forms. The explosion is very asymmetrical and has a total explosion energy of ∼1.6 × 1051 erg. At black hole formation, its baryon mass is ∼2.434 M ⊙ and gravitational mass is 2.286 M ⊙. Seven seconds after black hole formation, an additional ∼0.2 M ⊙ is accreted, leaving a black hole baryon mass of ∼2.63 M ⊙. A disk forms around the proto−neutron star, from which a pair of neutrino-driven jets emanates. These jets accelerate some of the matter up to speeds of ∼45,000 km s−1 and contain matter with entropies of ∼50. The large spatial asymmetry in the explosion results in a residual black hole recoil speed of ∼1000 km s−1. This novel black hole formation channel now joins the other black hole formation channel between ∼12 and ∼15 M ⊙ discovered previously and implies that the black hole/neutron star birth ratio for solar-metallicity stars could be ∼20%. However, one channel leaves black holes in perhaps the ∼5–15 M ⊙ range with low kick speeds, while the other leaves black holes in perhaps the ∼2.5–3.0 M ⊙ mass range with high kick speeds. However, even ∼8.8 s after core bounce the newly formed black hole is still accreting at a rate of ∼2 × 10−2 M ⊙ s−1, and whether the black hole eventually achieves a significantly larger mass over time is yet to be determined. [ABSTRACT FROM AUTHOR]

In this paper, we propose and experimentally study a simple linear cavity multiwavelength Brillouin-Raman fiber laser (MBRFL). The fiber feedback loop which consists of an optical circulator is placed at the end of the dispersion compensating fiber (DCF) to enhance the reflectivity of the Brillouin Stokes waves. As a result, 245 Brillouin Stokes lines with 0.072 nm channel-spacing are generated across the wavelength range of 18.6 nm from 1544.98 to 1563.58 nm when Brillouin pump (BP) is fixed to 1545 nm/−2.94 dBm and a single Raman pump (RP) laser power is set to 718 mW. The output spectrum is reshaped based on Rayleigh scattering by adding 45 km single mode fiber (SMF) in the cavity. The average optical signal to noise ratio (OSNR) about 18 dB has been measured in this structure. A tunable multiwavelength range of 20 nm from 1545 to 1565 nm is obtained. We also demonstrate the influence of BP wavelength and power on MBRFL. [ABSTRACT FROM AUTHOR]

A unified picture to understand the protein recognition and function must include the native binding complex structure ensembles and the underlying binding mechanisms involved in specific biological processes. However, quantifications of both binding complex structures and dynamical mechanisms are still challenging for IDP. In this study, we have investigated the underlying molecular mechanism of the chaperone Chz1 and histone H2A.Z-H2B association by equilibrium and kinetic stopped-flow fluorescence spectroscopy. The dependence of free energy and kinetic rate constant on electrolyte mean activity coefficient and urea concentration are uncovered. Our results indicate a previous unseen binding kinetic intermediate. An initial conformation selection step of Chz1 is also revealed before the formation of this intermediate state. Based on these observations, a mixed mechanism of three steps including both conformation selection and induced fit is proposed. By combination of the ion- and denaturant-induced experiments, we demonstrate that electrostatic forces play a dominant role in the recognition of bipolar charged intrinsically disordered protein Chz1 to its preferred partner H2A.Z-H2B. Both the intra-chain and inter-chain electrostatic interactions have direct impacts on the native collapsed structure and binding mechanism. [ABSTRACT FROM AUTHOR]

In order to achieve high accuracy of autonomous navigation for Mars probes, an integrated navigation method using X-ray pulsar measurement and optical data of viewing Martian moons is proposed. For single X-ray pulsar measurement on board a Mars probe, navigation accuracy is low due to its poor observability. On the other hand, Phobos and Deimos, two natural moons of Mars, are important optical navigation information sources available for Mars missions. However, the Martian moons ephemeris bias and the differences between barycentre and centre of brightness of Martian moons will result in low navigation accuracy. The method of integrated navigation using X-ray pulsar measurement and optical data of viewing Martian moons can overcome the defect and achieve accurate navigation. Two sequential orbit determination algorithms, Extended Kalman Filter (EKF) and Unscented Kalman Filter (UKF), are compared. The simulation results show this method can obtain high autonomous navigation accuracy during the phase of a probe orbiting Mars. [ABSTRACT FROM PUBLISHER]

We experimentally demonstrate a thulium–holmium co-doped hybrid mode-locked fiber laser, which can operate in two modes. One is the switch between stretched pulse and dissipative soliton, the other is the dual-wavelength mode-locking corresponding to the coexistence of stretched pulse and dissipative soliton. The optical spectra of the stable dual-wavelength mode-locking pulses centers at 1905 nm and 1946 nm respectively, and the corresponding pulse widths are 5.9 ps and 823 fs. In addition, the central wavelength is in the tunable range of 27 nm when the laser operates on a dissipative soliton regime. • Switching and coexistence of dissipative soliton and stretched pulse are realized in a hybrid mode-locked fiber laser. • Stable dual-wavelength mode-locking with different types of pulses are obtained without polarization-maintaining fiber. • The variations of pulse energy and peak power of dissipative soliton and stretched pulse with pump power are analyzed. • Tuning range of dissipative soliton wavelength from 1883 nm to 1910 nm. [ABSTRACT FROM AUTHOR]

How to improve both security and energy efficiency is one of the most prominent issues in wireless sensor networks (WSNs). In this paper, we present a trusted and energy efficient approach for cluster-based WSNs. The approach offers (i) trusted hardware module design; (ii) energy-efficient clustering algorithm; and (iii) network operation. In the cluster-based WSNs, every cluster head is equipped with a designed trusted hardware module (TM) to improve security. Then, for improving the energy efficiency of the network, a trusted hardware based energy efficient clustering (TEEC) algorithm is proposed to select appropriate cluster heads. In the network operation, we use TEEC algorithm to perform clustering and apply TMs to achieve security functions. The analysis shows that our approach does well in resisting the attacks such as data confidentiality attack, data integrity attack, and compromise node attack. In addition, experimental results show that the TEEC algorithm makes more balanced clusters with the variance value of loads around 50% and prolongs the life cycle of the network at least 10% compared to traditional methods. [ABSTRACT FROM AUTHOR]

A hybrid composite constructed of phospholipids bilayer membrane, gold nanoparticles and graphene was prepared and used as matrices for microperoxidase-11 (MP11) immobilization. The direct electrochemistry and corresponding bioelectrocatalysis of the enzyme electrode was further investigated. Phospholipid bilayer membrane protected gold nanoparticles (AuNPs) were assembled on polyelectrolyte functionalized graphene sheets through electrostatic attraction to form a hybrid bionanocomposite. Owing to the biocompatible microenvironment provided by the mimetic biomembrane, microperoxidase-11 entrapped in this matrix well retained its native structure and exhibited high bioactivity. Moreover, the AuNPs–graphene assemblies could efficiently promote the direct electron transfer between the immobilized MP11 and the substrate electrode. The as-prepared enzyme electrode presented good direct electrochemistry and electrocatalytic responses to the reduction of hydrogen peroxide (H 2 O 2 ). The resulting H 2 O 2 biosensor showed a wide linear range (2.0×10 −5 –2.8×10 −4 M), a low detection limit (2.6×10 −6 M), good reproducibility and stability. Furthermore, this sensor was used for real-time detection of H 2 O 2 dynamically released from the tumor cells MCF-7 in response to a pro-inflammatory stimulant. [ABSTRACT FROM AUTHOR]

Here, a cytosensor was constructed with ferrocene-appended poly(allylamine hydrochloride) (Fc-PAH) functionalized graphene (Fc-PAH-G), poly(sodium- p -styrenesulfonate) (PSS) and aptamer (AS1411) by layer-by-layer assembly technology. The hybrid nanocomposite Fc-PAH-G not only brings probes on the electrode and also promotes electron transfer between the probes and the substrate electrode. Meanwhile, LBL technology provides more effective probes to enhance amplified signal for improving the sensitivity of the detection. While AS1411 forming G-quardruplex structure and binding cancer cells, the current response of the sensing electrode decreased due to the insulating properties of cellular membrane. Differential pulse voltammetry (DPV) was performed to investigate the electrochemical detection of HeLa cells attributing to its sensitivity of the current signal change. The as-prepared aptasensor showed a high sensitivity and good stability, a widely detection range from 10 to 10 6 cells/mL with a detection limit as low as 10 cells/mL for the detection of cancer cells. [ABSTRACT FROM AUTHOR]

G-quadruplex (G4), as one of the significant functional nucleic acids (FNAs), has attracted researchers’ wide attention, and in particular has been employed for the construction of label-free molecular sensors and logic systems based on the peroxidase-like activity of the G4–hemin complex and G4-enhanced luminescence of G4-binding organic dyes. Its cation-dependent conformation and stability provide opportunities for the recognition of metal ion inputs and application of a split G4 strategy. Moreover, coupling the G4 sequence with other FNAs, e.g. metal ion-dependent DNAzymes and aptamers, has prominently broadened the range of possible targets from metal ions and DNA to diverse proteins and cells. Although there are limitations, such as a low ability of anti-interference and multiplex analysis, the excellent advantages (e.g. simplicity and low cost) endow the G4-mediated strategy with tremendous potential to be further exploited for practical bioanalysis and complicated DNA computing. [ABSTRACT FROM AUTHOR]

A simple and versatile method is described to construct high performance three-dimensional (3D) graphene-based enzyme biosensor. Monolithic and macroporous 3D graphene foam grown by chemical vapor deposition (CVD) was used as a freestanding electrode for co-immobilization of horseradish peroxidase (HRP) and a commonly used redox mediator, methylene blue (MB). Carbon nanotubes (CNTs) were employed as carriers of MB molecules to immobilize them on 3D graphene surface through strong π-π stacking force. Mussel-inspired biopolymer polydopamine (PDA) was formed by in-situ polymerization and served as a green linker, which could covalently graft HRP on the surface of 3D graphene/MB-CNTs electrode. In addition, PDA layer could also effectively prevent the leakage of inner electron mediators. Owing to the 3D macroporous architecture, exceptional properties of graphene and surface-bound mediators, the biosensor demonstrated outstanding performance for reagentless detection of H 2 O 2 in terms of wide linear range (0.2 μM to 1.1 mM), high sensitivity (227.8 μA mM −1 cm −2 ), low detection limit (58.0 nM), and fast response (reaching 95% of the steady current within 3 s). The biosensor exhibited high reproducibility and stability. [ABSTRACT FROM AUTHOR]

In arid and semi-arid regions, water scarcity and soil salinization are major factors impacting sustainable agricultural production. In this study, a macroscopic root-water-uptake model was used to adapt a plant water deficit index (PWDI) for irrigation scheduling under conditions of coexisting soil water and salinity stress-causing factors. The traditional approach, estimating PWDI with average root zone soil water and salt amounts, was improved by weighting the effects of soil water and salinity according to the normalized root length density profile. An experiment growing wheat (Triticum aestivum L.) in soil columns and an experiment growing cotton (Gossypium hirsutum L.) in a salinized field were implemented to explore and quantify the effects of soil water and salinity conditions on plant water status, and thus to validate the improvement and evaluate its application, by monitoring soil water and salinity dynamics and plant growth indexes (e.g., leaf area, dry weight, leaf water potential, transpiration and yield). The results indicate that, even under conditions with equal root zone averages of soil matric and osmotic potentials, plant water status might be significantly different. In general, plants were less stressed when more water and less salinity were allocated in the upper root zone with more roots while less water and more salinity occurred in the lower root zone with less roots. By referring to some information in the soil column experiment, a numerical experiment was conducted to further demonstrate the improvement. The root-weighted approach resulted in improved PWDI estimation and thus was more reliable for irrigation scheduling, leading to higher irrigation frequency and quantity, leaf area index, biomass, yield, and transpiration, without significant decrease in water productivity. However, further improvement could be possible by considering the effects of historical soil water and salinity stresses as well as meteorological conditions on plant water status. • Relative position of soil water and salt to roots affects plant water status. • Root-weighted approach can enhance estimation of plant water deficit index (PWDI). • PWDI under salinity was studied for wheat in soil columns and cotton in field. • Root-weighted PWDI estimation improves irrigation scheduling in salinized field. [ABSTRACT FROM AUTHOR]

This paper presents a modified passive dynamic walking model with hip friction. We add Coulomb friction to the hip joint of a two-dimensional straight-legged passive dynamic walker. The walking map is divided into two parts – the swing phase and the impact phase. Coulomb friction and impact make the model's dynamic equations nonlinear and non-smooth, and a numerical algorithm is given to deal with this model. We study the effects of hip friction on gait and obtain basins of attraction of different coefficients of friction. [ABSTRACT FROM AUTHOR]

The solar sail is a new type of spacecraft for deep space exploration that is propelled by solar radiation pressure. The solar sail is large, has a large moment of inertia, and is highly flexible, and its motion involves a coupling of the orbit, the attitude, and structural vibration. With the coupling effect of the orbit and the attitude included, a non-Keplarian displaced solar orbit is designed. In the rotating frame, the solar sail has a stable equilibrium point, and an attitude controller is employed for coupled attitude-orbit control. With control, the time required for eliminating the orbital deflection is much larger than that required for the attitude deflection. Including the additional influence of the flexibility of the solar sail, the structure shows a sustained, high-frequency vibration, which also leads to sustained and high-frequency likewise small vibrations of the orbit and attitude. This work demonstrates the importance of including the structural flexibility into the coupling effect of the solar sail for long-term missions in space. [ABSTRACT FROM AUTHOR]

This paper presents a new planar passive dynamic model with contact between the feet and the ground. The Hertz contact law and the approximate Coulomb friction law were introduced into this human-like model. In contrast to McGeer's passive dynamic models, contact stiffness, contact damping, and coefficients of friction were added to characterize the walking model. Through numerical simulation, stable period-one gait and period-two gait cycles were found, and the contact forces were derived from the results. After investigating the effects of the contact parameters on walking gaits, we found that changes in contact stiffness led to changes in the global characteristics of the walking gait, but not in contact damping. The coefficients of friction related to whether the model could walk or not. For the simulation of the routes to chaos, we found that a small contact stiffness value will lead to a delayed point of bifurcation, meaning that a less rigid surface is easier for a passive model to walk on. The effects of contact damping and friction coefficients on routes to chaos were quite small. [ABSTRACT FROM PUBLISHER]

This paper studies the global synchronization of a new hyperchaotic Lorenz system proposed by Wang et al. Based on the Lyapunov stability theory, the coupled control matrix is discussed when either knowing or unknowing the system boundary, respectively. The analysis of theory and numerical simulations show that the synchronization of hyperchaos Lorenz system can be realized effectively with the methods. [ABSTRACT FROM AUTHOR]

This paper studies a type of single scroll attractor chaos system. Based on the research of Jiang et al. the global synchronization method is designed, and moreover, the author uses a combined synchronization of linear and nonlinear feedback, active control, single vector and unidirectional coupling synchronization three methods else, the problem of synchronization between same and different chaotic systems are realized by the four methods, respectively. The range of control function parameter is discussed according to the Routh-Hurwitz criterion and numerical simulations show the effectiveness of them. [ABSTRACT FROM AUTHOR]

In this paper, a type of new fractional order hyperchaotic Lorenz system is proposed. Based on the fractional calculus predictor-corrector algorithm, the fractional order hyperchaotic Lorenz system is investigated numerically, and the simulation results show that the lowest orders for hyperchaos in hyperchaotic Lorenz system is 3.884. According to the stability theory of fractional order system, an improved state-observer is designed, and the response system of generalized synchronization is obtained analytically, whose feasibility is proved theoretically. The synchronization method is adopted to realize the generalized synchronization of 3.884-order hyperchaotic Lorenz system, and the numerical simulation results verify the effectiveness. [ABSTRACT FROM AUTHOR]

Green manure is important for crop yield sustainability. However, its impact on methane (CH 4) emissions in paddy soils is poorly understood. Based on a 37-year experiment, we linked methanogenic and methanotrophic communities to CH 4 emissions under a green manure-based double rice cropping system. The treatments were: ryegrass-rice-rice (R), milk vetch-rice-rice (M) and fallow-rice-rice (F). The early and late rice yield where within the range of 3760.0 and 4933.3 kg ha−1, and 5040.0 and 6373. 3 kg ha−1, respectively. Meanwhile, the CH 4 fluxes ranged from, 0.02–168.71 mg m−2 h−1. Green manure increased annual rice yield by 16.1–25.3%, as against F (P < 0.05). However, R increased cumulative CH 4 emissions by 90.2% (P < 0.05) whereas M showed no significant stimulation, relative to F. The total CH 4 emissions notably correlated with dissolved organic carbon (DOC) (r = 0.80, P < 0.01) and the gene copy numbers of mcrA (r = 0.78, P < 0.05), but not pmoA (r = 0.65, P > 0.05). The relative abundances of acetoclastic methanogens belonging to the family Methanosarcinaceae , and hydrogenotrophic methanogens of the orders Methanocellales and Methanobacteriales , were lower in M, as against R (P < 0.05), and correlated with the total CH 4 emissions (r = 0.90, 0.84, 0.96, respectively, P < 0.01). Our findings suggest that leguminous green manure improves rice yield, and mitigates CH 4 emissions by regulating both acetoclastic and hydrogenotrophic methanogenic communities. • Green manuring significantly increased annual rice yield by 16.1–25.3%. • R significantly increased total CH 4 emissions, relative to M and F. • Methanosarcinaceae , Methanocellales and Methanobacteriales were significantly lower in M, as against R. • Legume green manuring is a good approach for increasing rice yield and mitigating CH 4 emission. [ABSTRACT FROM AUTHOR]

Aims To use selected ion flow tube mass spectrometry (SIFT-MS) to analyse the molecular species emitted by heated ‘street’ cannabis plant material, especially targeting ammonia. Materials and methods Samples of ‘street’ cannabis leaf, held under a UK Home Office licence, were prepared by finely chopping and mixing the material. The samples were then heated in commercially available devices. The air containing the released gaseous compounds was sampled into the SIFT-MS instrument for analysis. Smoke from standard 3% National Institute on Drug Abuse (NIDA) cannabis cigarettes was also analysed. Findings For ‘street’ cannabis, ammonia was present in the air samples from the devices at levels approaching 200 parts per million (p.p.m.). This is compared with peak levels of 10 p.p.m. using NIDA samples of known provenance and tetrahydrocannabinol content (3%). Several other compounds were present at lower levels, including acetaldehyde, methanol, acetone, acetic acid and uncharacterized terpenes. Conclusions Awareness of the risks of inhaling the smoke directly from burning cannabis has led to the development of a number of alternative methods of delivery, which are claimed to be safer than direct smoking. Ammonia at toxic levels is produced from heating ‘street’ cannabis in these commercially available devices. Thus, the use of these devices to deliver ‘street’ cannabis is now open to question and further research is needed to investigate their safety. [ABSTRACT FROM AUTHOR]

Abstract: A study has been carried out of the reactions of three isomers of hydroxybutyric acid, giving special attention to 3-hydroxybutyric acid, 3-HBA, with H3O+ and NO+ ions to acquire the required kinetic data for a selected ion flow tube mass spectrometry, SIFT-MS, search for 3-HBA in the headspace of urine since it is known to be one of the “ketone bodies” important in the diagnosis of ketoacidosis. Thus, the product ions formed in the reactions of the H3O+ and NO+ precursor ions with the three hydroxy acids were established by sampling the headspace above the pure compounds over a range of absolute humidities from 1.5% (ambient air) to 6% (liquid headspace at 37C and exhaled breath). Then these data, together with the rate coefficients for the reactions estimated by calculation, were used to detect and quantify 3-HBA in the headspace of an aqueous solution of this compound of known concentration and above urine donated by two volunteers. The level of 3-HBA above the urine samples after they were acidified with hydrochloric acid was seen to be typically 40 parts-per-billion, ppb, which is much lower than that for acetone seen to be typically 800ppb. Exploiting the aqueous solution data as a reference, the 3-HBA concentration in the urine samples was estimated to be about 1–2mmol/L, which is typical of the urine from healthy individuals. [Copyright &y& Elsevier]

Abstract: We have carried out a selected ion flow tube (SIFT) study of the reactions of H3O+, NO+ and O2+• with the following 10 compounds: 2-hydroxyphenol, 2-, 3- and 4-methylphenol (o-, m- and p-cresol, respectively), 4-ethylphenol, 1-phenylmethanol (benzyl alcohol), 1- and 2-phenylethanol, 1,4-benzoquinone and cyclohexanone. The primary purpose of this work was to extend the kinetics database to allow these compounds (M), to be analysed in air by selected ion flow tube mass spectrometry (SIFT-MS). The initial step in all the H3O+ reactions is exothermic proton transfer to produce MH+ ions, which are observed as the only products for seven of the ten reactions, but for the three aromatic alcohols, H2O molecule elimination occurred from the nascent MH+ ions producing the corresponding hydrocarbon ion. This is an essential point to recognise when exploiting proton transfer to analyse these compounds using SIFT-MS and proton transfer reaction mass spectrometry, PTR-MS. NO+ reacts with six of the compounds via non-dissociative charge transfer producing M+ ions and this is a valuable route to their analysis by SIFT-MS. In the case of the NO+/quinone reaction, adduct formation occurs giving NO+M product ions, whilst for the remaining three reactions two or more ion products were formed. All the O2+• reactions proceeded via charge transfer with multiple ion products in most cases. A sample analysis is carried out to indicate the value of simultaneous use of both H3O+ and NO+ precursor ions to analyse a mixture containing some of these compounds. [Copyright &y& Elsevier]