Aboveground Biomass Retrieval in Tropical and Boreal Forests Using L-Band Airborne Polarimetric Observations

Forests play a crucial part in regulating global climate change since their aboveground biomass (AGB) relates to the carbon cycle, and its changes affect the main carbon pools. At present, the most suitable available SAR data for wall-to-wall forest AGB estimation are exploiting an L-band polarimetric SAR. However, the saturation issues were reported for AGB estimation using L-band backscatter coefficients. Saturation varies depending on forest structure. Polarimetric information has the capability to identify different aspects of forest structure and therefore shows great potential for reducing saturation issues and improving estimation accuracy. In this study, 121 polarimetric decomposition observations, 10 polarimetric backscatter coefficients and their derived observations, and six texture features were extracted and applied for forest AGB estimation in a tropical forest and a boreal forest. A parametric feature optimization inversion model (Multiple linear stepwise regression, MSLR) and a nonparametric feature optimization inversion model (fast iterative procedure integrated into a K-nearest neighbor nonparameter algorithm, KNNFIFS) were used for polarimetric features optimization and forest AGB inversion. The results demonstrated the great potential of L-band polarimetric features for forest AGB estimation. KNNFIFS performed better both in tropical (R2 = 0.80, RMSE = 22.55 Mg/ha, rRMSE = 14.59%, MA%E = 12.21%) and boreal (R2 = 0.74, RMSE = 19.82 Mg/ha, rRMSE = 20.86%, MA%E = 20.19%) forests. Non-model-based polarimetric features performed better compared to features extracted by backscatter coefficients, model-based decompositions, and texture. Polarimetric observations also revealed site-dependent performances

Genome-Wide Association Study Reveals Candidate Genes for Growth Relevant Traits in Pigs

Improvement of the growth rate is a challenge in the pig industry, the Average Daily Gain (ADG) and Days (AGE) to 100 kg are directly related to growth performance. We performed genome-wide association study (GWAS) and genetic parameters estimation for ADG and AGE using the genomic and phonemic from four breed (Duroc, Yorkshire, Landrace, and Pietrain) populations. All analyses were performed by a multi-loci GWAS model, FarmCPU. The GWAS results of all four breeds indicate that five genome-wide significant SNPs were associated with ADG, and the nearby genomic regions explained 4.08% of the genetic variance and 1.90% of the phenotypic variance, respectively. For AGE, six genome-wide significant SNPs were detected, and the nearby genomic regions explained 8.09% of the genetic variance and 3.52% of phenotypic variance, respectively. In total, nine candidate genes were identified to be associated with growth and metabolism. Among them, TRIB3 was reported to associate with pig growth, GRP, TTR, CNR1, GLP1R, BRD2, HCRTR2, SEC11C, and ssc-mir-122 were reported to associate with growth traits in human and mouse. The newly detected candidate genes will advance the understanding of growth related traits and the identification of the novel variants will suggest a potential use in pig genomic breeding programs

Segmented optimal design of ballistic trajectory of gliding extended range projectile subjected to multiple constraints

AbstractGliding extended range projectile is restricted by such conditions as the speed, the engine thrust force, the engine work time and the impact point speed inclination when attaining the longest range. To simplify the problem and acquire a well-designed trajectory, a phase-based method for optimizing the overall trajectory is presented. The overall trajectory is divided into the boosted phase, the cruise phase, the gliding phase and the terminal guidance phase. After overall consideration of the constraints and index requirements of all phases, different methods were used to optimize each phase, including the optimal angle of firing design, the design for minimizing energy loss, the optimal glide design and the terminal phase dive method, so as to optimize the overall trajectory. Simulation results show that the designed trajectory can meet the design requirements for multiple constraints and achieve the longest extended range as well as 10 km–70 km whole range coverage. The conclusion is of certain significance in developing rocket projectiles

Sensing of Soil Organic Matter Using Laser-Induced Breakdown Spectroscopy Coupled with Optimized Self-Adaptive Calibration Strategy

Rapid quantification of soil organic matter (SOM) is a great challenge for the health assessment and fertility management of agricultural soil. Laser-induced breakdown spectroscopy (LIBS) with appropriate modeling algorithms is an alternative tool for this measurement. However, the current calibration strategy limits the prediction performance of the LIBS technique. In this study, 563 soil samples from Hetao Irrigation District in China were collected; the LIBS spectra of the soils were recorded in the wavenumber range of 288–950 nm with a resolution of 0.116 nm; a self-adaptive partial least squares regression model (SAM–PLSR) was employed to explore optimal model parameters for SOM prediction; and calibration parameters including sample selection for the calibration database, sample numbers and sample location sites were optimized. The results showed that the sample capacity around 60–80, rather than all of the samples in the soil library database, was selected for calibration from a spectral similarity re-ordered database regarding unknown samples; the model produced excellent predictions, with R2 = 0.92, RPD = 3.53 and RMSEP = 1.03 g kg−1. Both the soil variances of the target property and the spectra similarity of the soil background were the key factors for the calibration model, and the small sample set led to poor predictions due to the low variances of the target property, while negative effects were observed for the large sample set due to strong interferences from the soil background. Therefore, the specific unknown sample depended strategy, i.e., self-adaptive modelling, could be applied for fast SOM sensing using LIBS for soils in varied scales with improved robustness and accuracy

Thermodynamic Analysis of a Hybrid System Coupled Cooling, Heating and Liquid Dehumidification Powered by Geothermal Energy

The utilization of geothermal energy is favorable for the improvement of energy efficiency. A hybrid system consisting of a seasonal heating and cooling cycle, an absorption refrigeration cycle and a liquid dehumidification cycle is proposed to meet dehumidification, space cooling and space heating demands. Geothermal energy is utilized effectively in a cascade approach. Six performance indicators, including humidity efficiency, enthalpy efficiency, moisture removal rate, coefficient of performance, cooling capacity, and heating capacity, are developed to analyze the proposed system. The effect of key design parameters in terms of desiccant concentration, air humidity, air temperature, refrigeration temperature and segment temperature on the performance indicators are investigated. The simulation results indicated that the increase of the desiccant concentration makes the enthalpy efficiency, the coefficient of performance, the moisture removal rate and the cooling capacity increase and makes the humidity efficiency decrease. With the increase of air humidity, the humidity efficiency and moisture removal rate for the segment temperatures from 100 to 130 °C are approximately invariant. The decreasing rates of the humidity efficiency and the moisture removal rate with the segment temperature of 140 °C increases respectively. Six indicators, except the cooling capacity and heating capacity, decrease with an increase of air temperature. The heating capacity decreases by 49.88% with the reinjection temperature increasing from 70 to 80 °C. This work proposed a potential system to utilize geothermal for the dehumidification, space cooling and space heating effectively

Role of Interfacial Structure of Water in Polymer Surface Wetting

We present a theoretical approach to investigate the structures and contact angles of water in contact with different polymer surfaces. In the theoretical approach, the three-dimensional reference interaction site model integral equation and the three-dimensional density functional method are combined through the bridge function. First, the three-dimensional distribution functions of water over the crystalline polyethylene surface and the amorphous polyethylene, polypropylene and polystyrene surfaces are calculated. According to the isosurface representations of the distributions, the wetting processes of these four polymer surfaces are simply analyzed. Then, the three-dimensional distributions of free energy are calculated by the density functional equation to obtain the interfacial tensions. Finally, the contact angles are estimated. It is shown that the predicted contact angles are in good agreement with the literature data, indicating that above structure and energy descriptions are quantitatively reasonable

The Inflammation-Related Gene S100A12 Is Positively Regulated by C/EBPβ and AP-1 in Pigs

S100A12 is involved in the inflammatory response and is considered an important marker for many inflammatory diseases in humans. Our previous studies indicated that the S100A12 gene was abundant in the immune tissues of pigs and was significantly upregulated during infection with Haemophilus parasuis (HPS) or porcine circovirus type 2 (PCV2). In this study, the mechanism of transcriptional regulation of S100A12 was investigated in pigs. Our results showed that S100A12, CCAAT/enhancer-binding protein beta (C/EBPβ) and activator protein-1 (AP-1) genes were up-regulated in PK-15 (ATCC, CCL-33) cells when treated with LPS or Poly I: C. Additionally, the promoter activity and expression level of the S100A12 gene were significantly upregulated when C/EBPβ or AP-1 were overexpressed. We utilized electromobility shift assays (EMSA) to confirm that C/EBPβ and AP-1 could directly bind the S100A12 gene promoter. We also found that the transcriptional activity and expression levels of C/EBPβ and AP-1 could positively regulate each other. Furthermore, the promoter activity of the S100A12 gene was higher when C/EBPβ and AP-1 were cotransfected than when they were transfected individually. We concluded that the S100A12 gene was cooperatively and positively regulated by C/EBPβ and AP-1 in pigs. Our study offers new insight into the transcriptional regulation of the S100A12 gene

Polyamidoxime/Poly(vinyl alcohol) Composite Chelating Fiber Prepared by Emulsion Spinning and Its Adsorption Properties for Metal Ions

The precursor polyacrylonitrile/poly­(vinyl alcohol) (PAN/PVA) fibers were prepared by emulsion spinning of PAN emulsion with PVA solution. The precursor fibers were then amidoximated to get the polyamidoxime (PAO)/PVA composite chelating fibers. The structures of PAN emulsion particles and composite fiber were studied with a laser mastersizer, scan electronic microscope, Fourier transform infrared spectra, auto-Kjeldahl determination, and X-ray diffraction analysis. Results show that nanosized PAN particles were well-dispersed in PVA fiber matrix through emulsion spinning. Almost all of the PAN particles were amidoximated after treatment. The PAO/PVA fiber has good selectivity to silver ions in a multiple metal ions solution. Its maximum amount of adsorption of silver ions and copper ions were calculated to be 518 and 146 mg g^–1 according to the Langmuir model. It also has good mechanical performance with breaking strength, 392.10 MPa, and elongation at break, 30.19%