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Ground-Based Synthetic Aperture Radar (GB-SAR), due to its high precision, high resolution, and real-time capabilities, is widely used in the detection of slope deformations. However, the weak scattering coefficient in low-coherence areas poses a great challenge to the observation point selection accuracy. This paper introduces a selection process for reliable observation points that integrates phase and spatial information. First, for various observation points with differentiated stability, we propose to utilize maximum likelihood estimation (MLE) methods to achieve stability assessment. Second, a phase correction approach is proposed to address unwrapped phase errors encountered at less stable points. Third, adaptive filtering for deformation information at observation points is achieved using estimated variance combined with wavelet filtering thresholds. Finally, in dealing with unknown deformation trends, we propose utilizing a clustering method to accurately identify these trends, thereby enhancing the precision in identifying reliable observation points (ROPs). The experimental results demonstrate that this method enhances the accuracy of observation point selection in low-coherence areas, providing a broader observational field for deformation detection. [ABSTRACT FROM AUTHOR]

A trend in the development of spaceborne Synthetic Aperture Radar (SAR) technology is the shift from a single-satellite repeated observation mode to a multi-satellite collaborative observation mode. However, current multi-satellite collaborative geolocation algorithms face challenges, such as geometric model mismatch and poor baseline estimation accuracy, arising from highly dynamic changes among multi-satellites. This paper introduces a high-precision and efficient geolocation algorithm for a spaceborne bistatic interferometric SAR (BiInSAR) system based on an improved range–Doppler (IRD) model. The proposed algorithm encompasses three key contributions. Firstly, a comprehensive description of the spatial baseline geometric model unique to the bistatic configuration is provided, with a specific focus on deriving the perpendicular baseline expression. Secondly, IRD geolocation functions are established to meet the specific requirements of the bistatic configuration. Then, a novel BiInSAR geolocation algorithm based on the IRD's functions is proposed, which can significantly improve the target geolocation accuracy by modifying the range–Doppler equation to suit the bistatic configuration. Meanwhile, a low-coupling parallel calculation method is proposed, which can improve the calculation speed by two to three times. Finally, the accuracy and efficiency of the algorithm are demonstrated using experimental data acquired by the TH-2 satellite, which is China's first spaceborne BiInSAR system. The experimental results prove that the IRD algorithm exhibits geolocation accuracy with an average error of less than 1 m and a standard deviation of less than 2.5 m while maintaining computational efficiency at a calculation speed of 1,429,678 pixels per second. [ABSTRACT FROM AUTHOR]

Polarimetric Synthetic Aperture Radar (PolSAR) data is inherently characterized by speckle noise, which significantly deteriorates certain aspects of the quality of the PolSAR data processing, including the polarimetric decomposition and target interpretation. With the rapid increase in PolSAR resolution, SAR images in complex natural and artificial scenes exhibit non-homogeneous characteristics, which creates an urgent demand for high-resolution PolSAR filters. To address these issues, a new adaptive PolSAR filter based on joint similarity measure criterion (JSMC) is proposed in this paper. Firstly, a scale-adaptive filtering window is established in order to preserve the texture structure based on a multi-directional ratio edge detector. Secondly, the JSMC is proposed in order to accurately select homogeneous pixels; it describes pixel similarity based on both space distance and polarimetric distance. Thirdly, the homogeneous pixels are filtered based on statistical averaging. Finally, the airborne and spaceborne real data experiment results validate the effectiveness of our proposed method. Compared with other filters, the filter proposed in this paper provides a better outcome for PolSAR data in speckle suppression, edge texture, and the preservation of polarimetric properties. [ABSTRACT FROM AUTHOR]

• A 4-zone, 20-column carousel-type continuous lithium extraction process was designed. • Developed a multi-column composite model to describe the carousel-type continuous lithium extraction process. • Simulated the lithium extraction process through the model and achieved good lithium extraction results. A composite model has been developed to simulate and optimize the continuous multi-column lithium adsorption based on the continuous adsorption of lithium from high Mg/Li ratio brines. The model not only simulates all the adsorption columns of the adsorption process, but also the auxiliary equipment connected to the adsorption columns such as pumps and valves, to describe the multi-column continuous lithium extraction process in detail. To improve the efficiency of lithium extraction, a 4-zone, 20-column carousel-type continuous lithium extraction process was proposed and optimized using the composite model. When the feed flow rate was set to 25 mL/min in the adsorption zone, 8 mL/min in the washing zone and 15 mL/min in the product zone, the Li+ extraction rate in the adsorption zone was 98.26%, the lithium loss in the washing zone was 16.12%, the magnesium removal rate in the washing process was 98.77%, the concentration of lithium solution obtained in the product zone was 488.55 mg/L, and the magnesium-lithium ratio was 6.45, with a lithium recovery of 79.68% for the whole continuous lithium extraction process. Overall, the continuous carousel lithium extraction process achieved the expected magnesium separation and continuous lithium extraction from the brine of the Qarhan Salt Lake. [ABSTRACT FROM AUTHOR]

As a specific pearl mussel in China, Hyriopsis cumingii has enormous economic value. However, the organism damage caused by pearl insertion is immeasurable. TGF-β/Smad signal transduction pathways are involved in all phases of wound healing. We have previously reported on two cytoplasmic signal transduction factors, Smad3 and Smad5 in mussel H. cumingii (named HcSmads), suggesting their involvements in wound healing. Here, Smad4 was cloned and described. The full length cDNA of HcSmad4 was 2543 bp encoded 515 amino acids. Deduced HcSmad4 protein possessed conserved MH1 and MH2 domains, nuclear location signals (NLS), nuclear exput signals (NES) and Smad activation domain (SAD). Transcripts of Smad3, 4 and 5 were constitutively expressed in all detected tissues, at highest levels in muscles. Furthermore, HcSmad4 mRNA levels were significantly increased at incision site post wounding, and expression of downstream target genes of Smad4, such as HcMMP1, HcMMP19, HcTIMP1 and HcTIMP2 were upregulated to a certain extent. Whatever knocked down HcSmad3/4 or treated by specific inhibitors of Smad 3 (SIS3), expression levels of these genes displayed a significantly downregulated tendency compared with the wound group. In addition, histological evaluation suggested that Smad3 knockdown or SIS3 treatment was accelerated wound healing, and then Smad4 knockdown delayed the process of wound healing in mussels. These data implicate that Smad3/4 play an important role in tissue repair in mollusks. • The full length cDNA of HcSmad4 was 2543 bp. HcSmad4 mRNA levels were significantly increased post wounding. • The downstream genes of Smad4 were up-regulated after knocked down HcSmad3/4 or SIS3 treatment. • Smad3-knockdown was accelerated but Smad4 knockdown delayed wound healing in mussels. [ABSTRACT FROM AUTHOR]

Glutathione-S-transferases (GSTs) are multifunctional phase II detoxification enzymes that catalyze the attachment of electrophilic substrates to glutathione, and play an important role in protecting organisms against the toxicity of reactive oxygen species. In this study, two distinct sigma-class GST (CpGSTσ1 and 2) cDNA sequences were cloned from freshwater bivalve Cristaria plicata . The full length cDNA of CpGSTσ1 and 2 was 826 bp and 1609 bp, which encoded 213 and 248 amino acid residues, respectively. Their transcripts were expressed in all detected tissues and the highest expression level was in hepatopancreas from C. plicata . The expression level of CpGSTσ1 and 2 in hepatopancreas and hemocytes showed a significantly increased trend after bacterial challenge. The recombinant CpGSTσ1 was successfully expressed as a soluble form in Escherichia coli DE3. The specific activity of recombinase toward CDNB was 46.965 ± 0.082 μmol/min/mg, and its optimum temperature and pH was 37 °C and 9.0, respectively. The recombinant of CpGSTσ1 could bear 6 M urea and 8% SDS, when the concentration of urea was 8 M and its activity was only below 20%. The results might provide a better perspective on the mechanisms of resistance to bacterial infection in molluscs. [ABSTRACT FROM AUTHOR]

The solubility of l -methionine in three different binary mixed solvents of water + (methanol, ethanol, acetone) were experimentally measured by gravimetric method from T = (283.15 to 313.15) K ( P = 0.1 MPa). The experimental data indicate that the solubility of l -methionine in the binary mixed solvents increases with the increasing temperature and decreases with the rise of molar concentration of organic solvents. The modified Apelblat model, the λh model and the CNIBS/R–K model were used to correlate the experimental data, and all of the models provided good fitting to the data. Furthermore, the mixing thermodynamic properties of l -methionine in different binary solvent mixtures were also calculated and discussed. The results indicate that the mixing process of l -methionine in the investigated solvents is endothermic and spontaneous. The experimental solubility and correlation equations can be used as essential data and simulation models in the purification and separation of l -methionine. [ABSTRACT FROM AUTHOR]

microRNAs (miRNAs) regulate target gene expression through their ARGONAUTE (AGO) effector protein, mainly AGO1 in Arabidopsis thaliana. In addition to the highly conserved N, PAZ, MID and PIWI domains with known roles in RNA silencing, AGO1 contains a long, unstructured N-terminal extension (NTE) of little-known function. Here, we show that the NTE is indispensable for the functions of Arabidopsis AGO1, as a lack of the NTE leads to seedling lethality. Within the NTE, the region containing amino acids (a.a.) 91 to 189 is essential for rescuing an ago1 null mutant. Through global analyses of small RNAs, AGO1-associated small RNAs, and miRNA target gene expression, we show that the region containing a.a. 91–189 is required for the loading of miRNAs into AGO1. Moreover, we show that reduced nuclear partitioning of AGO1 did not affect its profiles of miRNA and ta-siRNA association. Furthermore, we show that the 1-to-90a.a. and 91-to-189a.a. regions of the NTE redundantly promote the activities of AGO1 in the biogenesis of trans-acting siRNAs. Together, we report novel roles of the NTE of Arabidopsis AGO1. Author summary: Gene expression regulation through microRNAs (miRNAs) is widely adopted in eukaryotes. miRNAs are short RNAs ranging from 19 to 24 nucleotides, and associate with a protein named ARGONAUTE (AGO) to form miRNA-induced silencing complexes (miRISCs). A miRISC then binds to a target messenger RNA (mRNA) with sequence complementary to the miRNA, resulting in reduced expression of the target gene. AGO proteins contain four highly conserved domains: N, PAZ, MID and PIWI. Many AGO proteins also possess an N-terminal extension (NTE) region of varying lengths and sequences, of which the function is little known. In plants, most miRNAs are preferentially loaded into AGO1. In this study, we investigated the role of Arabidopsis AGO1 NTE, which is 189 amino acids (a.a.) long and highly unstructured with undefined function. By examining AGO1 mutants with truncated NTE, we show that the 91-to-189a.a. region of the NTE is essential for rescuing the developmental phenotype of an ago1 null mutant and is required for loading miRNAs into AGO1. Moreover, we show that 1-to-90a.a. and 91-to-189a.a. regions of the NTE redundantly promote the activities of AGO1 in the biogenesis of trans-acting small interfering RNAs, a type of endogenous small RNAs that require miRNAs for their biogenesis. [ABSTRACT FROM AUTHOR]

This Letter proposes a high‐precision and non‐iterative polarimetric synthetic aperture radar (SAR) (PolSAR) calibration algorithm. By solving a system of non‐linear equations, the distortion parameters can be obtained directly. The proposed algorithm is assessed by the simulated PolSAR data. The experimental results show that the algorithm can accurately solve all distortion parameters even though the crosstalk is high and has a better estimation performance compared with the widely used non‐iterative Quegan algorithm. [ABSTRACT FROM AUTHOR]

This article concerns the analysis and compensation of track deviations in high-resolution automobile synthetic aperture radar (SAR). We establish the geometry in which the automobile-SAR raw data is acquired. Based on the derived model, the research investigates the impact of track deviations on the final focused image quality and we propose a motion compensation strategy which can be applied to obtain a well-focused SAR image. This article presents how to obtain the accurate positions of the antenna phase centre using the velocity and attitude angles measured by inertial navigation system/global positioning system, and proposes a new method to compensate for forward velocity errors which are decomposed into two components and compensated individually, that is, high-order and low-order phase compensation. Finally, the results from both simulated data and real data are presented to validate the whole analysis and the proposed procedure. [ABSTRACT FROM PUBLISHER]

Abstract: Rehmannia glutinosa, a widely used Chinese medicinal herb, has been shown to suffer from serious consecutive monoculture problems that cause significant decline in both yield and quality. The objective of this study was to evaluate the response of the soil microbial community and the effect on catabolic diversity to consecutive monoculture regime using three different techniques: substrate-induced respiration (SIR), phospholipid fatty acid (PLFA) and community-level physiological profiles (CLPP) analyses. We found that basal soil respiration (BSR) was significantly higher in the control and newly planted soils than in the second and third year consecutive monoculture soils. However, no significant difference was observed in SIR among the newly planted, second and third year consecutive monoculture soils. The PLFA signatures indicated that the bacterial biomass was larger than the fungal biomass in all four treatments and both enhanced with the increasing years of monoculture and attained the peak in SM. The ratio of cyclopropyl PLFAs to their metabolic precursors (cy/pre), a measure of physiological stress in microbial communities, in the second and third year consecutive monoculture soils was significantly greater than that in the control and newly planted soils. Biolog analysis results revealed that the consumption of carboxylic acids, phenolic acids and amines, especially acid carbon substrates, in the consecutively monocultured soil was significantly greater than that in the newly planted soil. Both PLFA- and CLPP-based principal component analysis (PCA) and cluster analysis revealed the distinct separation between the control, newly planted plots and the second, third year consecutive monoculture plots. Through our PLFA-based and Biolog analysis, together with microbial respiration determination, we were able to reveal characteristic differences in the microbial community composition and activities in the rhizosphere following R. glutinosa monoculture. [Copyright &y& Elsevier]

2-D phase unwrapping is an important technique in many applications. However, with the growth of image scale, how to tile and splice the image effectively has become a new challenge. In this paper, the phase unwrapping problem is abstracted as solving a large-scale system of inconsistent linear equations. With the difficulties of large-scale phase unwrapping analyzed, L^0-norm criterion is found to have potentials in efficient image tiling and splicing. Making use of the clustering characteristic of residue distribution, a tiling strategy is proposed for L^0-norm criterion. Unfortunately, L^0-norm is an NP-hard problem, which is very difficult to find an exact solution in a polynomial time. In order to effectively solve this problem, equations corresponding to branch cuts of L^0-norm in the inconsistent equation system mentioned earlier are considered as outliers, and then an outlier-detection-based phase unwrapping method is proposed. Through this method, a highly accurate approximate solution to this NP-hard problem is achieved. A set of experimental results shows that the proposed approach can avoid the inconsistency between local and global phase unwrapping solutions caused by image tiling. [ABSTRACT FROM AUTHOR]

Multibaseline phase unwrapping is a critical processing procedure of multibaseline synthetic aperture radar interferometry (InSAR). It has an advantage over single-baseline phase unwrapping in discontinuous-terrain-height estimation. In this paper, the pixels' combination information of multiple InSAR interferograms with different baseline lengths is deeply investigated, and the term ambiguity vector is proposed to represent a pixel's ambiguity number of multiple interferograms. It is also revealed that pixels with the same ambiguity vector have an exclusive pattern among them. A fast cluster-analysis (CA)-based method is proposed for multibaseline phase unwrapping. In this method, all pixels are first clustered into different groups according to their patterns, and then, information of the cluster center is used to unwrap the phases of pixels group by group. Simulation results are shown to verify the effectiveness, efficiency, and noise robustness of CA multibaseline phase-unwrapping method. [ABSTRACT FROM AUTHOR]

In this paper we investigate the possibility to produce high‐resolution synthetic aperture radar (SAR) images of wide areas from the data collected by the distributed small spaceborne SAR systems. In particular, we focus on the data processing techniques for overcoming the Doppler ambiguity effects characterizing ground echoes and achieving high‐resolution SAR images of wide areas. A novel approach is proposed, the key idea of which is to retrieve the unambiguous azimuth wide (full) spectrum signal from the received ground echoes by using a space–time adaptive processing (STAP) algorithm to overcome the Doppler aliasing effect induced by the lower pulse repetition frequency (PRF); following this operation, conventional SAR data processing tools can be applied to fully focus the SAR images. The STAP‐based approach has the advantages of simplicity, robustness and high efficiency. We also discuss the array configuration requirements, and give a platform velocity/PRF criterion for array configurations. [ABSTRACT FROM AUTHOR]

Panama disease (Fusarium wilt disease) caused by Fusarium oxysporum f. sp. cubense race 4 (FOC) severely threatens banana (Musa spp.) production worldwide. Intercropping of banana with Allium plants has shown a potential to reduce Panama disease. In this study, six cultivars of Chinese chive (Allium tuberosum Rottler) were selected to compare their differences in antifungal activity and active compounds. Three cultivars Duokang Fujiu 11, Fujiuhuang 2, and Duokang Sijiqing with higher levels of antifungal compounds were further used for intercropping with banana in the pots and field to compare their effects on growth and disease incidence of banana. The six cultivars showed significant differences in antifungal activity against FOC mycelia growth in both leaf volatiles and aqueous leachates. The aqueous leachates displayed stronger antifungal activity than the volatiles. FJH cultivar showed the best inhibitory effect among all six cultivars. Contents of three main antifungal compounds dipropyl trisulfide (DPT), dimethyl trisulfide (DMT), and 2-methyl-2-pentenal (MP) in volatiles and aqueous leachates varied considerably among cultivars. Pot and field experiments showed that intercropping with three selected Chinese chive cultivars significantly improved banana vegetative growth, increased photosynthetic characteristics and yield but decreased disease incidence of Panama disease. Our results indicate that intercropping with Chinese chive shows potential to reduce banana Panama disease and selection of appropriate cultivars is vital for effective disease control. [ABSTRACT FROM AUTHOR]

Polarimetric SAR (PolSAR) scattering characteristics of imagery are always obtained from the second order moments estimation of multi-polarization data, that is, the estimation of covariance or coherency matrices. Due to the extra-paths that signal reflected from separate scatterers within the resolution cell has to travel, speckle noise always exists in SAR images and has a severe impact on the scattering performance, especially on single look complex images. In order to achieve high accuracy in estimating covariance or coherency matrices, three aspects are taken into consideration: (1) the edges and texture of the scene are distinct after speckle filtering; (2) the statistical characteristic should be similar to the object pixel; and (3) the polarimetric scattering signature should be preserved, in addition to speckle reduction. In this paper, a joint restriction principle is proposed to meet the requirement. Three different restriction principles are introduced to the processing of speckle filtering. First, a new template, which is more suitable for the point or line targets, is designed to ensure the morphological consistency. Then, the extent sigma filter is used to restrict the pixels in the template aforementioned to have an identical statistic characteristic. At last, a polarimetric similarity factor is applied to the same pixels above, to guarantee the similar polarimetric features amongst the optional pixels. This processing procedure is named as speckle filtering with joint restriction principle and the approach is applied to GF-3 polarimetric SAR data acquired in San Francisco, CA, USA. Its effectiveness of keeping the image sharpness and preserving the scattering mechanism as well as speckle reduction is validated by the comparison with boxcar filters and refined Lee filter. [ABSTRACT FROM AUTHOR]

Potassium chloride crystals are cubic, which often leads to caking and greatly limits their applications. This caking can be overcome by modifying the crystal shape toward sphericity. Spherical particles have a high anti-caking ability and flowability. In this work, spherical KCl particles were prepared using a simple cooling crystallization process designed to function without additives. Among the four main processes in the crystallization of spherical particles, i.e., nucleation, growth, agglomeration, and attrition, agglomeration is the greatest contributor to the formation of spherical KCl particles, which were prepared following the principle that the adhesion force must be larger than the dispersion force. The adhesion free energy between KCl particles and solvents (i.e., water, n -hexane, formamide, diazomethane, methanol, ethanol, ethyl acetate, ethylene glycol, and dimethyl sulfoxide) was calculated using the Lifshitz–van der Waals acid–base approach, and water was found to be the most appropriate solvent because of its attractive interaction with the crystals. According to the relationship between the adhesion force and dispersion forces, we found that the stirring rate should be lower than 1300 rpm. Additionally, the effects of stirring rate and cooling rate on the KCl products were investigated and optimized, and the optimal conditions were found to be 400–500 rpm and 10–15 min/ ° C, respectively. All of the spherical KCl products prepared under the optimal conditions show a better morphology, flowability, and anti-caking performance than the original crystals. [ABSTRACT FROM AUTHOR]

The proteins of Smad family are critical components of the TGF-β superfamily signal pathway. In this paper, we cloned two intracellular mediators of TGF-β signaling, Smad3 and Smad5, from the pearl mussel Hyriopsis cumingii. The full length cDNA of HcSmad3 and HcSmad5 were 2052 bp and 1908 bp and encoded two polypeptides of 418 and 461amino acid residues, respectively. The deduced amino acid of HcSmad3 and HcSmad5 possessed two putative conserved domains, MH1 and MH2, a conserved phosphorylation motif SSXS at the carboxyl-terminal. The two Smad genes were detected muscle, mantle, hepatopancreas and gill, but with a very low level in heamocytes. The transcripts of Smad3 and Smad5 were up-regulated in hemocytes and hepatopancreas after A. hydrophila and PGN stimulation. However, the expression of Smad3 and Smad5 were only up-regulated in hepatopancreas after A. hydrophila stimulation. The transcripts of Smad3 and Smad5 had a slight change in hepatopancreas after PGN stimulation. The transcripts of HcSmad3 showed very little increase and HcSmad5 mRNA significantly up-regulated after wounding. [ABSTRACT FROM AUTHOR]

Catalytic ammonia decomposition is an attractive method to generate hydrogen at mid-temperatures (<700 °C) but must incorporate precious metals (Pd, Ru, etc.) to ensure high reactivity. Developing Ni-based catalysts to decompose ammonia can enhance its prospect for hydrogen generation. However, the catalytic activity of Ni is hardly satisfactory at mid-temperatures. In this work, we show the bimetallic Ni x Co 10-x /CeO 2 towards mid-temperature NH 3 decomposition, with the metal loading of Ni and Co tuned. Kinetics study demonstrates that the NH 3 decomposition reaction follows the Temkin Pyzhev mechanism and the synergy between Ni and Co can decrease the reaction orders regarding NH 3 and increase the reaction orders regarding H 2. Mechanistic results indicate that the recombinative N desorption limits the reaction rate. The synergy between Ni and Co can simultaneously decrease the energy barriers of the recombinative N desorption and mitigate the H 2 poisoning effect. Therefore, Ni 7.5 Co 2.5 /CeO 2 displays both high ammonia conversion (96.96%) and hydrogen formation rate (1947.9 mmol/(g cat.h)) at 650 °C. We hope the mechanism in this work can be used to guide the design of inexpensive catalysts to decompose ammonia at mid-temperatures. [Display omitted] • NH 3 decomposition over Ni x Co 10-x /CeO 2 follows the Temkin Pyzhev mechanism. • The recombinative desorption of N is the rate-limiting step. • The generated H 2 can poison the active sites on the surface. • The synergy between Ni and Co can decrease the energy barriers of the rate-limiting step and mitigate the H 2 poisoning. • Ni 7.5 Co 2.5 /CeO 2 is an effective catalyst towards mid-temperature NH 3 decomposition. [ABSTRACT FROM AUTHOR]

Fe 2 O 3 is prospective for the chemical looping redox cycles but must contain a significant amount of inert supports to ensure high stability. The traditional inert supports (Al 2 O 3 , MgAl 2 O 4 , etc.) have a dilution effect on Fe 2 O 3 , which results in a compromised reactivity. In this work, we propose several Sr, Mg co-doped LaGaO 3-δ to support Fe 2 O 3 for chemical looping water splitting and investigated the synergy for the enhanced performance. Mechanistic study manifests that doping Sr increases the amount of oxygen vacancies, promoting the oxygen release and uptake during the redox reaction. Doping Mg mitigated the interaction between Fe 2 O 3 and the supports, leading to much enhanced stability. Therefore, Fe 2 O 3 /La 0.6 Sr 0.4 Mg 0.4 Ga 0.6 O 3-δ shows both high hydrogen yield (9.75 mmol.g−1) and peak hydrogen production rate (3.7 mmol.g−1.min−1). The performance shows only a slight decrease even after 100 cycles. The observed results can also inspire the selection and development of advanced supports to improve both the reactivity and stability of oxygen carriers. [Display omitted] • Sr improves oxygen vacancy concentration of the oxygen carriers. • High oxygen vacancy concentration improves the oxygen release/uptake rate. • Mg mitigates the reaction between iron and support to ensure reversible phase change. • Fe 2 O 3 /La 0.6 Sr 0.4 Mg 0.4 Ga 0.6 O 3-δ is highly active and stable for chemical looping reaction. [ABSTRACT FROM AUTHOR]

Ground-based synthetic aperture radar (GB-SAR) is a highly effective technique that is widely used in landslide and bridge deformation monitoring. GB-SAR based on multiple input multiple output (MIMO) technology can achieve high accuracy and real-time detection performance. In this paper, a novel method is proposed to design transmitting and receiving array elements, which increases the minimum spacing of the antenna by sacrificing several equivalent phase centers. In MIMO arrays, the minimum antenna spacing in the azimuth direction is doubled, which increases the variety of antenna options for this design. To improve the accuracy of the system, a new method is proposed to estimate channel phase errors, amplitude errors, and position errors. The position error is decomposed into three directions with one compensated by the phase error and two estimated by the strong point. Finally, we validate the accuracy of the system and our error estimation method through simulations and experiments. The results prove that the GB-SAR system performs well in bridge deformation and vibration monitoring with the proposed method. [ABSTRACT FROM AUTHOR]

High accuracy in complex images coregistration is essential in ground moving target indication (GMTI) processing of synthetic aperture radar (SAR) data, normally termed SAR-GMTI. The clutter suppression performance is proportional to the coregistration accuracy. In this correspondence, we propose a new SAR-GMTI approach, which is robust to the SAR images coregistration error. The observed clutter-plus-noise vector is built using the neighboring pixels as the first step, thus the corresponding covariance matrix, termed as joint covariance matrix, can be estimated. The joint noise subspace is obtained by eigen-decomposing of the joint covariance matrix. The clutter is suppressed successfully by a projecting operation, i.e., a projection of the joint observed vector into the resulting joint noise subspace. The information of neighboring pixels is substantially exploited in the clutter suppression, resulting in the robustness, even at the presence of large coregistration error. Both the simulated and real multi-channel airborne data are used to validate the proposed approach. [ABSTRACT FROM PUBLISHER]

This paper deals with the imaging problem for sliding spotlight (SS) and terrain observation by progressive scan (TOPS) modes in bistatic configuration of the geostationary (GEO) transmitter with a low earth orbit satellite (LEO) receiver, named GTLR-BiSAR system. A unified imaging algorithm is proposed to process the GTLR-BiSAR data acquired in SS or TOPS modes. Our main contributions include four aspects. Firstly, the imaging geometry of this novel configuration is described in detail. Furthermore, the GTLR-BiSAR signal expressions were deduced in both time and frequency domains. These signal expressions provide great support for the design of processing the algorithm theoretically. Secondly, we present a unified deramping-based technique according to the special geometry of GTLR-BiSAR to overcome the azimuth spectrum aliasing phenomenon, which typically affects SS and TOPS data. Thirdly, the spatial variance of GTLR-BiSAR data were thoroughly analyzed based on the range-Doppler (RD) geolocation functions. On the basis of a former analysis, we put forward the azimuth variance correction strategy and modified the conventional chirp scaling function to solve the range variance problem. Finally, we completed the derivation of the two-dimensional spectrum after the range chirp scaling. On the basis of spectrum expressions, we compensated for the quadratic and residue phase, and the azimuth compression was completed by SPECAN operation. In addition, we provide a flow diagram to visually exhibit the processing procedures. At the end of this paper, the simulation and real data experiment results are presented to validate the effectiveness of the proposed algorithm. [ABSTRACT FROM AUTHOR]

In forward‐looking imaging, left‐right Doppler is ambiguous and cross‐range resolution is limited by real aperture, which result in traditional synthetic aperture radar imaging methods no longer applicable. Besides, the impact of three‐dimensional acceleration on an over‐complete dictionary matrix and sparse reconstruction kernel is not considered in conventional super‐resolution forward‐looking imaging methods. To solve these problems, a super‐resolution forward‐looking imaging method for manoeuvering platforms is proposed. First, the range walk caused by forward‐looking geometry and higher‐order phase introduced by three‐dimensional acceleration are eliminated by compensating a pre‐processing function. Subsequently, according to beam steering‐based geometry and linear regression model, the over‐complete dictionary matrix is optimised to more accurately describe the complicated forward‐looking geometry with curved trajectory. Finally, sparsity adaptive matching pursuit kernel with an improved halting condition is adopted to reconstruct the forward‐looking scene. The proposed method is supported by point target simulation and surface target simulation. [ABSTRACT FROM AUTHOR]

Honeybees cannot synthesize arachidonic acid (ARA) themselves, only obtain it from food. Most pollen is deficient or contains a small amount of ARA. The necessity of supplementary ARA in bees' diet has not been studied. The objective of this study was to investigate the effects of dietary ARA levels on the growth and immunity of Apis mellifera ligustica. A total of 25 honeybee colonies were randomly assigned to five dietary groups which were fed basic diets supplemented with 0, 2, 4, 6, and 8% of ARA. The diet with 4% ARA improved the body weight of newly emerged worker bees compared with the control group. Supplement of ARA in honeybee diets changed the fatty acid composition of honeybee body. SFA and MUFA contents of bees' body declined, and PUFA content rised in the ARA group. Compared with the control group, the supplement of ARA in honeybee diets increased the contents of ARA, C22:6n-3 (DHA) and C18:3n-6 in bees' body significantly, but decreased the contents of C16:1 and C18:3n-3. The diet supplied with 4% ARA reduced the mortality rate of honeybee infected with Escherichia coli. The activity of immune enzymes (phenoloxidase, antitrypsin, and lysozyme) and the mRNA expression levels of immune genes (defensin-2, toll, myd88, and dorsal) were improved by ARA diets to varying degrees depending on the ARA levels, especially 4% ARA. These results suggested that dietary ARA could improve the growth, survival, and immune functions of honeybees. Supplement of ARA in bees' diet would be valuable for the fitness of honeybees. [ABSTRACT FROM AUTHOR]

By applying digital beam‐forming (DBF) technique, the along‐track multi‐channel synthetic aperture radar (SAR) system can simultaneously achieve high‐resolution and wide‐swath (HRWS) imaging. However, the presence of unavoidable phase biases tends to degrade the DBF performance. To address this issue, a novel phase bias estimation algorithm based on Doppler spectrum optimisation is proposed. By exploiting the fact that phase bias would cause Doppler spectrum broadened, the phase biases can be successfully estimated by maximising a sharpness optimisation of the Doppler spectrum. The effectiveness of the algorithm is validated by experimental result carried out on the SAR data collected by an air‐borne multi‐channel system. [ABSTRACT FROM AUTHOR]

The rapid accumulation of lignin in the cell wall is one of important immune defense mechanism in response to adversity stress in plants. In this study, we found that the enlargement of the root tubers of Rehmannia glutinosa (R. glutinosa) is arrested under consecutive monoculture stress, and this process is accompanied by abnormal accumulation of lignin. Meanwhile, the function of key catalytic enzyme genes in lignin biosynthetic pathway under consecutive monoculture stress was systematically analyzed, of which roles of core genes were validated using reverse genetics. We elucidated that an abnormal deposition of lignin in R. glutinosa roots, induced by consecutive monoculture stress, and arrested the enlargement of root tubers. Additionally, by manipulating the key catalytic enzyme gene RgCCR6 , we were able to alter lignin content of roots of R. glutinosa , thereby affecting tuber enlargement. We speculate that cell lignification is an important defense strategy in resistance against consecutive monoculture stress, but the overreacted defense hindered the normal enlargement of root tubers. The findings provide new insights for effectively improving yield reductions of root crops subjected to environmental stress. • Consecutive monoculture stress induced special deposition of lignin in the cambium cells. • Over-immunity led to abnormal deposition of lignin in cambium cells. • Abnormal deposition of lignin limited root tubers enlargement. • RgCCR in lignin biosynthesis was core node affected root tubers enlargement. [ABSTRACT FROM AUTHOR]

The solubility of calcium d -pantothenate in (water + methanol) mixtures and the effect of β -alanine on the solubility of calcium d -pantothenate in a constant mole ratio of methanol and water was measured from 263.15 K to 303.15 K by the HPLC analysis method ( P = 0.1 MPa). The solubility of calcium d -pantothenate increased with increasing temperature in all the mixtures at constant composition. Besides, it also increased with mole fraction of water in (water + methanol) mixtures at a constant temperature. Additionally, the solubility of calcium d -pantothenate was enhanced by β -alanine at a given temperature. The experimental solubility in (water + methanol) mixtures was correlated by the modified Apelblat equation, the ternary NRTL equation and Solubility-Polarity Model. The Apelblat equation, the quaternary NRTL equation and the Cohn equation were adopted to correlate the experimental solubility in the (water + methanol + β -alanine) mixtures. Worthwhile, the quaternary NRTL equation was first applied to correlating the quaternary solid-liquid equilibrium. It turned out that all the selected models give good performance on solubility prediction. [ABSTRACT FROM AUTHOR]

A laser monitoring dynamic method was used to determine the solubility of 4-aminobutyric acid in five mono-solvents of methanol, formamide, 1,2-propanediol, 1,3-propanediol and water, and (methanol + water) binary solvent mixtures over the temperature ranging from 283.15 K to 323.15 K at atmospheric pressure. It turns out to be that in different mono-solvents, the solubility of 4-aminobutyric acid is temperature dependent and increases with the increasing temperature. While in (methanol + water) binary solvent mixtures, the solubility is positively correlated with temperature and negatively correlated with the mole fraction of methanol. The modified Apelblat equation, λh equation and NRTL_Binary model were employed to correlate the solubility data in five mono-solvents. While in (methanol + water) binary solvent mixtures, the NRTL_Ternary model, CNIBS/R-K model and Jouyban-Acree models were applied. It is found that the correlated results are in good agreement with the experimental results. Furthermore, with the activity coefficients considered, solution mixing thermodynamics were calculated and the dissolution process of 4-aminobutyric acid is also discussed. [ABSTRACT FROM AUTHOR]

In multi‐channel high‐resolution and wide‐swath (HRWS) synthetic aperture radar (SAR) processing, range sampling time errors and phase mismatches severely degrade the reconstruction performance of unambiguous Doppler spectrum. To address this problem, an improved channel mismatch estimation algorithm for multi‐channel HRWS SAR is presented in this Letter. The technique of combining phase wrapping and weighted least‐squares fitting is capable of realising a robust estimation of range sampling time errors and constant phases between adjacent channels. Then, Doppler centroid as well as channel phase mismatches can be estimated from these constant phases based on the theory of spatial cross‐correlation coefficient (SCCC). Compared to the conventional algorithm, the improved performance can be achieved by using the proposed two‐step procedure. The effectiveness of the proposed algorithm is confirmed by experimental results based on airborne real data. [ABSTRACT FROM AUTHOR]

Those comments from Acree on “Effect of β -alanine and the solvent composition on the solubility of solvate of calcium d -pantothenate containing four molecules of methanol and one molecule of water ( d -PC·4MeOH·1H 2 O)” are very valuable and helpful for improving the quality of our paper. Here according to the comments, we make a deep analysis and discussion of our article again. Firstly, we need to make a restatement that S 0 and S actually represent the solubility with no impurity in the solution and the solubility in the solution containing impurity in our article, respectively. Secondly, the experimental solubility was reanalysed by the new Cohen equation suggested by Acree Jr, and the results show that the original Cohen equation could give the better agreement. Finally, the modified Solubility-Polarity equation was adopted to correlate the solubility in terms of the relative dielectric constant. [ABSTRACT FROM AUTHOR]

Pseudostellariae heterophylla, an important medicinal plant, has been shown to suffer from serious replanting disease that causes significant declines in both yield and quality. The objective of this study was to isolate the soil-born pathogen and antagonistic microorganism for investigation of the relationship between these microorganism and consecutive monoculture problems of P heterophylla. In this study, we isolated the bacteria with different morphology from P heterophylla rhizosphere soil, detected the pathogenicity of these bacteria to P heterophylla plantlet and antagonistic ability to Fusarium of P heterophylla biotype, identified their species and analyzed their abundance with qRT-PCR in rhizosphere soil of different planting years. We isolated Enterobacter sp1 and Burkholderia sp1 from P heterophylla rhizosphere soil, and found Enterobacter sp1 possessed the pathogenicity to P heterophylla plantlet and Burkholderia sp1 was antagonistic for Fusarium of P heterophylla biotype. However, Burkholderia sp1 was not the antagonistic microorganism to Enterobacter sp1. The growth of Enterobacter sp1 was stimulated by phenolic acids at a certain concentration nearly closed to that in P heterophylla rhizosphere soil, which increased as planting years of P heterophylla increased. On the contrary, the phenolic acids had no promoting effect on the growth of Burkholderia sp1. And with the increase of planting years, the abundance of Burkholderia sp1 decreased and abundance of Enterobacter sp1 increased in the P heterophylla rhizosphere soil. The results indicated that harmful microorganisms increase and beneficial microorganisms decrease, which were mediated by the accumulated autotoxins in rhizosphere soil of consecutively monocultured P heterophylla, and hence leads to the imbalance of microbial community structure and the degradation of soil ecological function. So several abatement methods, such as crop rotation, specific microbial fertilizer and organic matter, could be used to improve the structure and functional diversity of microbial community, and overcome the obstacles of continuous cropping. © 2015 Friends Science Publishers [ABSTRACT FROM AUTHOR]

3D scene reconstruction from single‐pass circular synthetic aperture radar (CSAR) data has been a research hot spot in various remote sensing applications. Among existing literature, radargrammetry techniques and model assistant methods are two dominant approaches. However, the performance of these methods is limited in practical applications: radargrammetry techniques obtain merely one height value along vertical; model assistant approaches only work when valid models are given. A single‐pass CSAR 3D scene point cloud reconstruction method is proposed. First, the connection between an object and its projections in multi‐aspect SAR images is established with no auxiliary model. On the basis of the connection, voxels are classified into inner voxels (voxels beneath the target profile) and outside voxels (voxels outside of the target profile). Discarded all the outside voxels, the remained inner voxels are combined to form the 3D point cloud of the target. It is similar to the sculpturing process from a raw material to a piece of craft. Finally, a 3D scene is retrieved through assembling all reconstructed targets into a unified coordinate system. The feasibility of the proposed method is validated by the Gotcha Volumetric SAR Data Set. [ABSTRACT FROM AUTHOR]

Summary In most sexually reproducing plants, a single somatic, sub-epidermal cell in an ovule is selected to differentiate into a megaspore mother cell, which is committed to giving rise to the female germline. However, it remains unclear how intercellular signaling among somatic cells results in only one cell in the sub-epidermal layer differentiating into the megaspore mother cell. Here we uncovered a role of the THO complex in restricting the megaspore mother cell fate to a single cell. Mutations in TEX1 , HPR1 , and THO6 , components of the THO/TREX complex, led to the formation of multiple megaspore mother cells, which were able to initiate gametogenesis. We demonstrated that TEX1 repressed the megaspore mother cell fate by promoting the biogenesis of TAS3 -derived trans -acting small interfering RNA (ta-siRNA), which represses ARF3 expression. The TEX1 protein was present in epidermal cells, but not in the germline, and, through TAS3 -derived ta-siRNA, restricted ARF3 expression to the medio domain of ovule primordia. Expansion of ARF3 expression into lateral epidermal cells in a TAS3 ta-siRNA-insensitive mutant led to the formation of supernumerary megaspore mother cells, suggesting that TEX1- and TAS3- mediated restriction of ARF3 expression limits excessive megaspore mother cell formation non-cell-autonomously. Our findings reveal the role of a small-RNA pathway in the regulation of female germline specification in Arabidopsis . [ABSTRACT FROM AUTHOR]

In this study, quantitative real-time PCR (qPCR) was used to determine the amount of Fusarium oxysporum, an important replant disease pathogen in Pseudostellaria heterophylla rhizospheric soil. Moreover, HPLC was used to identify phenolic acids in root exudates then it was further to explore the effects of the phenolic acid allelochemicals on the growth of F. oxysporum f.sp. heterophylla. The amount of F. oxysporum increased significantly in P. heterophylla rhizosphere soil under a consecutive replant system as monitored through qPCR analysis. Furthermore, the growth of F. oxysporum f.sp. heterophylla mycelium was enhanced by root exudates with a maximum increase of 23.8%. In addition, the number of spores increased to a maximum of 12.5-fold. Some phenolic acids promoted the growth of F. oxysporum f.sp. heterophylla mycelium and spore production. Our study revealed that phenolic acids in the root secretion of P. heterophylla increased long with its development, which was closely related to changes in rhizospheric microorganisms. The population of pathogenic microorganisms such as F. oxysporum in the rhizosphere soil of P. heterophylla also sharply increased. Our results on plant-microbe communication will help to better clarify the cause of problems associated with P. heterophylla under consecutive monoculture treatment. [ABSTRACT FROM AUTHOR]