Application of Lyapunov matrix inequality based unsymmetrical saturated control to a multi-vectored propeller airship

The problem of the design of a controller for a multi-vectored propeller airship is addressed. The controller includes anti-windup that takes into account unsymmetrical actuator constraints. First, a linear transformation is applied to transform the unsymmetrical constraints into symmetric constraints with an amplitude-bounded exogenous disturbance. Then, a stability condition based on a quadratic Lyapunov function for the saturated closed-loop system is proposed. The condition considers both amplitude-bounded and energy-bounded exogenous disturbances. Thus, the controller design problem is transformed into a convex optimization problem expressed in a bilinear matrix inequality form. Two controller design methods were applied: one-step controller and traditional anti-windup controller. The one-step method obtains the controller and the anti-windup compensator in one step while the anti-windup controller method separates this process into the linear controller design and the compensator design. Simulation results showed that both controllers enlarge the stability zone of the saturation system and have good tracking performance. It is shown that the anti-windup controller design method not only has a larger region of stability, but the demanded actuator output exceeds the constraints less and has a smaller anti-windup coefficient matrix compared to the one-step method

Internal anatomy of a fossilized embryonic stage of the Cambrian-Ordovician scalidophoran Markuelia

The Wangcun fossil Lagerstätte in Hunan, South China, has yielded hundreds of fossilized embryos of Markuelia hunanensis representing different developmental stages. Internal tissues have only rarely been observed, impeding further understanding of the soft tissue anatomy, phylogenetic affinity and evolutionary significance of Markuelia. In this study, we used synchrotron radiation X-ray tomographic microscopy (SRXTM) to study a new collection of fossil embryos from the Wangcun fossil Lagerstätte. We describe specimens exhibiting a spectrum of preservation states, the best of which preserves palisade structures underneath the cuticle of the head and tail, distinct from patterns of centripetal mineralization of the cuticle and centrifugal mineralization of hypha-like structures, seen elsewhere in this specimen and other fossils within the same assemblage. Our computed tomographic reconstruction of these mineralization phases preserves the gross morphology of (i) longitudinal structures associated with the tail spines, which we interpret as the proximal ends of longitudinal muscles, and (ii) a ring-shaped structure internal to the introvert, which we interpret as a ring-shaped brain, as anticipated of the cycloneuralian affinity of Markuelia. This is the first record of a fossilized nervous system in a scalidophoran, and the first instance in Orsten-style preservation, opening the potential for further such records within this widespread mode of high-fidelity three-dimensional preservation

Identification and Nearly Full-Length Genome Characterization of Novel Porcine Bocaviruses

The genus bocavirus includes bovine parvovirus (BPV), minute virus of canines (MVC), and a group of human bocaviruses (HBoV1-4). Using sequence-independent single primer amplification (SISPA), a novel bocavirus group was discovered with high prevalence (12.59%) in piglet stool samples. Two nearly full-length genome sequences were obtained, which were approximately 5,100 nucleotides in length. Multiple alignments revealed that they share 28.7–56.8% DNA sequence identity with other members of Parvovirinae. Phylogenetic analyses indicated their closest neighbors were members of the genus bocavirus. The new viruses had a putative non-structural NP1 protein, which was unique to bocaviruses. They were provisionally named porcine bocavirus 1 and 2 (PBoV1, PBoV2). PBoV1 and PBoV2 shared 94.2% nucleotide identity in NS1 gene sequence, suggesting that they represented two different bocavirus species. Two additional samples (6V, 7V) were amplified for 2,407 bp and 2,434 bp products, respectively, including a partial NP1 gene and the complete VP1 gene; Phylogenetic analysis indicated that 6Vand 7V grouped with PBoV1 and PBoV2 in the genus of bocavirus, but were in the separate clusters. Like other parvoviruses, PBoV1, PBoV2, 6Vand 7V also contained a putative secretory phospholipase A2 (sPLA2) motif in the VP1 unique region, with a conserved HDXXY motif in the catalytic center. The conserved motif YXGXF of the Ca2+-binding loop of sPLA2 identified in human bocavirus was also found in porcine bocavirus, which differs from the YXGXG motif carried by most other parvoviruses. The observation of PBoV and potentially other new bocavirus genus members may aid in molecular and functional characterization of the genus bocavirus

Divergence in Eco-Physiological Responses to Drought Mirrors the Distinct Distribution of Chamerion angustifolium Cytotypes in the Himalaya–Hengduan Mountains Region

Polyploid species generally occupy harsher habitats (characterized by cold, drought and/or high altitude) than diploids, but the converse was observed for Chamerion angustifolium, in which diploid plants generally inhabit higher altitudes than their polyploid derivatives. Plants at high altitudes may experience cold-induced water stress, and we therefore examined the physiological responses of diploid and hexaploid C. angustifolium to water stress to better understand the ecological differentiation of plants with different ploidy levels. We conducted a common garden experiment by subjecting seedlings of different ploidy levels to low, moderate and severe water stress. Fourteen indicators of physiological fitness were measured, and the anatomical characteristics of the leaves of each cytotype were determined. Both cytotypes were influenced by drought, and diploids exhibited higher fitness in terms of constant root:shoot ratio (R:S ratio) and maximum quantum yield of PSⅡ (Fv/Fm), less reduced maximal photosynthetic rate (Amax), transpiration rate (E), intercellular CO2 concentration (Ci) and stomatal conductance (gs), and higher long-term water use efficiency (WUEL) under severe water stress than did hexaploids. Analysis of leaf anatomy revealed morphological adjustments for tolerating water deficiency in diploids, in the form of closely packed mesophyll cells and small conduits in the midvein. Our results indicate that diploid C. angustifolium is more tolerant of drought than hexaploid plants, ensuring the successful survival of the diploid at high altitudes. This eco-physiological divergence may facilitate the species with different cytotypes to colonize new and large geographic ranges with heterogeneous environmental conditions

Genome-wide identification and expression analysis of serine proteases and homologs in the silkworm Bombyx mori

<p>Abstract</p> <p>Background</p> <p>Serine proteases (SPs) and serine proteases homologs (SPHs) are a large group of proteolytic enzymes, with important roles in a variety of physiological processes, such as cell signalling, defense and development. Genome-wide identification and expression analysis of serine proteases and their homologs in the silkworm might provide valuable information about their biological functions.</p> <p>Results</p> <p>In this study, 51 SP genes and 92 SPH genes were systematically identified in the genome of the silkworm <it>Bombyx mori</it>. Phylogenetic analysis indicated that six gene families have been amplified species-specifically in the silkworm, and the members of them showed chromosomal distribution of tandem repeats. Microarray analysis suggests that many silkworm-specific genes, such as members of SP_fam12, 13, 14 and 15, show expression patterns that are specific to tissues or developmental stages. The roles of SPs and SPHs in resisting pathogens were investigated in silkworms when they were infected by <it>Escherichia coli</it>, <it>Bacillus bombysepticus</it>, <it>Batrytis bassiana </it>and <it>B. mori </it><it>nucleopolyhedrovirus</it>, respectively. Microarray experiment and real-time quantitative RT-PCR showed that 18 SP or SPH genes were significantly up-regulated after pathogen induction, suggesting that SP and SPH genes might participate in pathogenic microorganism resistance in <it>B. mori</it>.</p> <p>Conclusion</p> <p>Silkworm SP and SPH genes were identified. Comparative genomics showed that SP and SPH genes belong to a large family, whose members are generated mainly by tandem repeat evolution. We found that silkworm has species-specific SP and SPH genes. Phylogenetic and microarray analyses provide an overview of the silkworm SP and SPHs, and facilitate future functional studies on these enzymes.</p

Coupling of light from an optical fiber taper into silver nanowires

We report the coupling of photons from an optical fiber taper to surface plasmon modes of silver nanowires. The launch of propagating plasmons can be realized not only at ends of the nanowires, but also at the midsection. The degree of the coupling can be controlled by adjusting the light polarization. In addition, we present the coupling of light into multiple nanowires from a single optical fiber taper simultaneously. Our demonstration offers a novel method for optimizing plasmon coupling into nanoscale metallic waveguides and promotes the realization of highly integrated plasmonic devices.Comment: 5 pages, 4 figure

Investigation of the morbidity of dry eye among special crowd in Shunde district

AIM: To investigate the morbidity of dry eye in policeman of Shunde district, and to analyze the related factors and proposed methods of preventing and treating dry eye.<p>METHODS:Totally 650 policemen who came for physical examination in Shunde district recived questionnaire survey. The patients with dye eye disease were finally diagnosed through slit lamp examination, Schirmer test, tear film break-up time(BUT)measurement and keratoconjunctival fluorescent staining. The morbidity among different policemen was further analyzed and stasticed.<p>RESULTS:The results showed that 152 in 650 policemen suffered from dry eye disease, the ratio was 23.4%. Comparied with security police and crimanl police, the ratio in traffic police, patrolman,and back office police was significantly higher. The prevalence was higher when the ages were greater than 40.<p>CONCLUSION: Unsuitable working environment, air contamination are high risk factors of dry eye disease

Tailoring Au-core Pd-shell Pt-cluster nanoparticles for enhanced electrocatalytic activity

We have rationally synthesized and optimized catalytic nanoparticles consisting of a gold core, covered by a palladium shell, onto which platinum clusters are deposited (Au@Pd@Pt NPs). The amount of Pt and Pd used is extremely small, yet they show unusually high activity for electrooxidation of formic acid. The optimized structure has only 2 atomic layers of Pd and a half-monolayer equivalent of Pt (theta(Pt) approximate to 0.5) but a further increase in the loading of Pd or Pt will actually reduce catalytic activity, inferring that a synergistic effect exists between the three different nanostructure components (sphere, shell and islands). A combined electrochemical, surface-enhanced Raman scattering (SERS) and density functional theory (DFT) study of formic acid and CO oxidation reveals that our core-shell-cluster trimetallic nanostructure has some unique electronic and morphological properties, and that it could be the first in a new family of nanocatalysts possessing unusually high chemical reactivity. Our results are immediately applicable to the design of catalysts for direct formic acid fuel cells (DFAFCs).NSFC[20620130427]; MOST[2007DFC40440]; 973 Program[2009CB930703, 2007CB815303]; ENS; CNRS (UMR, LIA XiamENS)[8640

Method for Evaluation of Foxtail Millet Cooking and Edible Quality

Foxtail millet, a high-quality coarse cereal, is generally used to cook porridge. Cooked foxtail millet is another food product of this cereal. However, a systematic evaluation method for the eating quality of cooked foxtail millet has not yet been established. In this study, heater type, millet-to-water mass ratio, water type, and soaking time affecting the edible quality of cooked foxtail millet (Variety: Zhangzagu 13) were investigated. The hardness viscometer, colorimeter and sensory evaluation were used to comprehensively evaluate the edible quality of millet. The optimal cooking method was determined as follows: Firstly, put 300 g of millet in an electric cooker and wash twice with deionized water quickly. Secondly, add deionized water in a mass ratio of millet to water 1.0∶2.0 and soak for 30 min. Finally, cook millet for about 45 minutes in the essence rice mode. After cooking, stir well and stew for 20 min. This research provides an important scientific basis for foxtail millet cooking and edible quality evaluation