Genome-Wide Association Study Identifies Candidate Genes Related to Seed Oil Composition and Protein Content in Gossypium hirsutum L.

Cotton (Gossypium spp.) is a leading natural fiber crop and an important source of vegetable protein and oil for humans and livestock. To investigate the genetic architecture of seed nutrients in upland cotton, a genome-wide association study (GWAS) was conducted in a panel of 196 germplasm resources under three environments using a CottonSNP80K chip of 77,774 loci. Relatively high genetic diversity (average gene diversity being 0.331) and phenotypic variation (coefficient of variation, CV, exceeding 3.9%) were detected in this panel. Correlation analysis revealed that the well-documented negative association between seed protein (PR) and oil may be to some extent attributable to the negative correlation between oleic acid (OA) and PR. Linkage disequilibrium (LD) was unevenly distributed among chromosomes and subgenomes. It ranged from 0.10–0.20 Mb (Chr19) to 5.65–5.75 Mb (Chr25) among the chromosomes and the range of Dt-subgenomes LD decay distances was smaller than At-subgenomes. This panel was divided into two subpopulations based on the information of 41,815 polymorphic single-nucleotide polymorphism (SNP) markers. The mixed linear model considering both Q-matrix and K-matrix [MLM(Q+K)] was employed to estimate the association between the SNP markers and the seed nutrients, considering the false positives caused by population structure and the kinship. A total of 47 SNP markers and 28 candidate quantitative trait loci (QTLs) regions were found to be significantly associated with seven cottonseed nutrients, including protein, total fatty acid, and five main fatty acid compositions. In addition, the candidate genes in these regions were analyzed, which included three genes, Gh_D12G1161, Gh_D12G1162, and Gh_D12G1165 that were most likely involved in the control of cottonseed protein concentration. These results improved our understanding of the genetic control of cottonseed nutrients and provided potential molecular tools to develop cultivars with high protein and improved fatty acid compositions in cotton breeding programs through marker-assisted selection

QDs-Cavity Approach to Controlled Quantum Teleportation of GHZ-Like State

The experimental scheme for controlled quantum teleportation of tripartite GHZ-like state is presented. With the entanglement generating through the interaction between the quantum dots in microcavities and a single photon, the controlled teleportation can be realized by virtue of Faraday rotation, single photon detection and electron spin orientation measurement. The success probability of the scheme can reach 1 if the cavities are switchable to choice the appropriate Faraday rotation angle. The scheme can be easily generalized to the teleportation of multipartite GHZ-like state

Single photon emission from top-down etched III-nitride quantum dots

We report the single photon emission properties of III-nitride quantum dots (QDs) fabricated by electrochemical etching method from an epitaxial wafer. Through such top-down fabrication, QDs with diameters of sub-10 nm are obtained, embedded in GaN nanoneedles. Owing to the size induced quantum confinement effect, the photoluminescence of the QDs exhibits a 3.35 nm blueshift compared with that of the epitaxial wafer. At low temperature, a second order correlation value down to 0.123 is observed, indicating a high-purity single photon emission. Our QDs manifest single photon emission at a temperature up to 130 K with a high degree of polarization of 0.69, comparable to those QDs synthesized by epitaxial growth. Our work demonstrates single photon emission are viable in top-down QDs by electrochemical etching III-nitride wafers

Effect of the electric-field distribution on the morphology of dot-array gratings fabricated by AFM-based nanolithography

Copyright © 2017 Inderscience Enterprises Ltd. Local electric-field-induced anodic oxidation is one of the earliest and most extensively studied techniques in bias-assisted AFM nanolithography. The electric field provides the oxidation kinetics of nanoscale electrochemical reaction and controls the spacial resolution of the fabricated structures. Once electric field is formed, its distribution and intensity can be modified by changing the tip-sample voltage and separation. In this paper, the influence of the bias voltage on the three-dimensional (3D) radial electric field intensity distribution in the space between the tip and the sample, the influence of the electric field strength on dot-array grating structures and the morphology distribution of the nanodot structure in the dot-array grating have been analysed deeply

Active steering control based on preview theory for articulated heavy vehicles.

This paper investigates the active steering control of the tractor and the trailer for the articulated heavy vehicle (AHV) to improve its high-speed lateral stability and low-speed path following. The four-degree-of-freedom (4-DOF) single track dynamic model of the AHV with a front-wheel steered trailer is established. Considering that the road information at the driver's focus is the most clear and those away from the focus blurred, a new kind controller based on the fractional calculus, i.e., a focus preview controller is designed to provide the steering input for the tractor to make it travel along the desired path. In addition, the active steering controllers based on the linear quadratic regulator (LQR) and single-point preview controller respectively are also proposed for the trailer. However, the latter is designed on the basis of the articulation angle between the tractor and trailer, inspired by the idea of the driver's single-point preview controller. Finally, the single lane change maneuver and 90o turn maneuver are carried out. And the simulation results show that compared with the single-point preview controller, the new kind preview controller for the tractor can have good high speed maneuvering stability and low speed path tracking ability by adjusting the fractional order of the controller. On this basis, three different AHVs with the same tractor are simulated and the simulation results show that the AHV whose trailer adopts the single-point preview controller has better high-speed lateral stability and low-speed path tracking than the AHV whose trailer adopts the LQR controller

Polarization independent and angularly tunable high-Q filter using guided-mode resonance at high terahertz frequencies

Narrowband filtering with high Q factors, polarization independency and tunability at high THz frequencies is challenging. Here, combining guided mode resonance (GMR) and silicon on insulator (SOI) techniques, a narrowband filter with an experimental Q factor up to ∼ 450 at frequencies > 4 THz is presented. Its 90° structural symmetry leads to polarization independency and angular tunability of ∼ 56 GHz at an incidence angle of 7°. The filter has potential in various fields such as broadband communication, imaging and optical sensing

Responses of photosynthetic parameters to drought in subtropical forest ecosystem of China

The mechanism underlying the effect of drought on the photosynthetic traits of leaves in forest ecosystems in subtropical regions is unclear. In this study, three limiting processes (stomatal, mesophyll and biochemical limitations) that control the photosynthetic capacity and three resource use efficiencies (intrinsic water use efficiency (iWUE), nitrogen use efficiency (NUE) and light use efficiency (LUE)), which were characterized as the interactions between photosynthesis and environmental resources, were estimated in two species (Schima superba and Pinus massoniana) under drought conditions. A quantitative limitation analysis demonstrated that the drought-induced limitation of photosynthesis in Schima superba was primarily due to stomatal limitation, whereas for Pinus massoniana, both stomatal and non-stomatal limitations generally exhibited similar magnitudes. Although the mesophyll limitation represented only 1% of the total limitation in Schima superba, it accounted for 24% of the total limitations for Pinus massoniana. Furthermore, a positive relationship between the LUE and NUE and a marginally negative relationship or trade-off between the NUE and iWUE were observed in the control plots. However, drought disrupted the relationships between the resource use efficiencies. Our findings may have important implications for reducing the uncertainties in model simulations and advancing the understanding of the interactions between ecosystem functions and climate change

Robotic 3D Vision-Guided System for Half-Sheep Cutting Robot

Sheep body segmentation robot can improve production hygiene, product quality, and cutting accuracy, which is a huge change for traditional manual segmentation. With reference to the New Zealand sheep body segmentation specification, a vision system for Cartesian coordinate robot cutting half-sheep was developed and tested. The workflow of the vision system was designed and the image acquisition device with an Azure Kinect sensor was developed. Furthermore, a LabVIEW software with the image processing algorithm was then integrated with the RGBD image acquisition device in order to construct an automatic vision system. Based on Deeplab v3+ networks, an image processing system for locating ribs and spine was employed. Taking advantage of the location characteristics of ribs and spine in the split half-sheep, a calculation method of cutting line based on the key points is designed to determine five cutting curves. The seven key points are located by convex points of ribs and spine and the root of hind leg. Using the conversion relation between depth image and the space coordinates, the 3D coordinates of the curves were computed. Finally, the kinematics equation of the rectangular coordinate robot arm is established, and the 3D coordinates of the curves are converted into the corresponding motion parameters of the robot arm. The experimental results indicated that the automatic vision system had a success rate of 98.4% in the cutting curves location, 4.2 s time consumption per half-sheep, and approximately 1.3 mm location error. The positioning accuracy and speed of the vision system can meet the requirements of the sheep cutting production line. The vision system shows that there is potential to automate even the most challenging processing operations currently carried out manually by human operators