528 research outputs found

    Ultra-Orthogonal Forward Regression Algorithms for the Identification of Non-Linear Dynamic Systems

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    A new ultra-least squares (ULS) criterion is introduced for system identification. Unlike the standard least squares criterion which is based on the Euclidean norm of the residuals, the new ULS criterion is derived from the Sobolev space norm. The new criterion measures not only the discrepancy between the observed signals and the model prediction but also the discrepancy between the associated weak derivatives of the observed and the model signals. The new ULS criterion possesses a clear physical interpretation and is easy to implement. Based on this, a new Ultra-Orthogonal Forward Regression (UOFR) algorithm is introduced for nonlinear system identification, which includes converting a least squares regression problem into the associated ultra-least squares problem and solving the ultra-least squares problem using the orthogonal forward regression method. Numerical simulations show that the new UOFR algorithm can significantly improve the performance of the classic OFR algorithm

    A simple and rapid plate assay for screening of inulindegrading microorganisms using Lugol’s iodine solution

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    In this report, a simple and rapid agar plate assay was established for screening of halophilic, inulindegrading microorganisms. Two strains considered inulinolytic with this method were chosen and the inulinolytic activities in their culture supernatant were measured with the Somogyi-Nelson method, while their hydrolysis products of inulin were detected with TLC chromatogram.Key words: Screening, halophilic microorganism, inulinase, Lugol’s iodine solution

    Conformal Transmitarrays for Unmanned Aerial Vehicles Aided 6G Networks

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    Unmanned aerial vehicles (UAVs) aided wireless communications promise to provide high-speed cost-effective wireless connectivity without needing fixed infrastructure coverage. They are a key technology enabler for sixth generation (6G) wireless networks, where a three-dimensional coverage including space, aero and terrestrial networks are to be deployed to guarantee seamless service continuity and reliability. Owing to the aerodynamic requirements, it is highly desirable to employ conformal antennas that can follow the shapes of the UAVs to reduce the extra drag and fuel consumption. To enable hundred giga-bits-per-second (Gb/s) data rates and massive connectivity for 6G networks, conformal antenna arrays featured with high gains and beam scanning/multiple beams are demanded for millimeter-wave and higher-frequency-range communications. However, new challenges exist in designing and implementing high-gain conformal arrays for UAV platforms. In this article, we overview the recent advances in conformal transmitarrays for UAV-based wireless communications, introducing new design methodologies and high-lighting new opportunities to be exploited

    An Elliptical Cylindrical Shaped Transmitarray for Wide-Angle Multibeam Applications

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    A transmitarray antenna with an elliptical cylindrical shape is presented for a wide-angle multibeam radiation in this paper. The transmitarray has a cylindrical radiating aperture with an elliptical cross section, namely, elliptical cylindrical shape. Multiple feeds can be placed on the middle horizontal plane to realize multiple beams. Inspired by a two-dimensional (2-D) Ruze lens, the antenna shape and the phase compensation are jointly designed according to the desired maximal beam direction. Innovative methods including a feed refocusing analysis and a virtual focal length are utilized to achieve the phase compensation across the three-dimensional (3-D) aperture for multiple beam radiations with a small scanning loss. In order to validate the proposed antenna, a prototype operating in the millimeter-wave E band has been designed, fabricated and measured. By changing the position of the feeding gain horn along the refocusing arc, the main beam of antenna can be scanned to eleven directions. The measured peak boresight realized gain is 27 dBi at 70.5 GHz and a beam coverage of ±43° with a less than 2.7-dB scanning loss is obtained

    Polymorphism of the pig-implantation protein 3 (preis3) gene and its association with litter size traits

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    The pre-implantation protein 3 (prei3), which might play a role in pre-implantation embryogenesis, is one of the promising candidate genes for litter size traits in pigs. In this study, a single nucleotide polymorphism (SNP: T802G) in intron 6 of the pig prei3 gene was detected and a genotyping assay for this SNP was developed. An association study for this SNP with litter size was performed in two independent populations. One population consisted of crossbred sows derived from Landrace, Large White, Chinese Tongcheng and/or Chinese Meishan (Line DIV). The other population constituted of crossbred animals derived from Chinese Qingping and Duroc (QD). Statistical analysis demonstrated that, in first parity, 2.65 more piglets were born and 3.82 more piglets were born alive in sows in Line DIV with genotype TT than with genotype GG. For second and subsequent litters, in both the DIV and QD lines there were significant differences in the number of piglets born alive between TG and GG sows, with the TG sows producing more piglets born alive than the GG sows. These results suggest that the prei3 SNP is significantly associated with litter size in the two populations studied, and could be useful in selection for increasing litter size in pigs. Further investigations on more pig populations with large sample sizes are needed to confirm this. South African Journal of Animal Science Vol. 36(3) 2006: 209-21

    SUMO-2 promotes mRNA translation by enhancing interaction between eIF4E and eIF4G

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    Small ubiquitin-like modifier (SUMO) proteins regulate many important eukaryotic cellular processes through reversible covalent conjugation to target proteins. In addition to its many well-known biological consequences, like subcellular translocation of protein, subnuclear structure formation, and modulation of transcriptional activity, we show here that SUMO-2 also plays a role in mRNA translation. SUMO-2 promoted formation of the active eukaryotic initiation factor 4F (eIF4F) complex by enhancing interaction between Eukaryotic Initiation Factor 4E (eIF4E) and Eukaryotic Initiation Factor 4G (eIF4G), and induced translation of a subset of proteins, such as cyclinD1 and c-myc, which essential for cell proliferation and apoptosis. As expected, overexpression of SUMO-2 can partially cancel out the disrupting effect of 4EGI-1, a small molecule inhibitor of eIF4E/eIF4G interaction, on formation of the eIF4F complex, translation of the cap-dependent protein, cell proliferation and apoptosis. On the other hand, SUMO-2 knockdown via shRNA partially impaired cap-dependent translation and cell proliferation and promoted apoptosis. These results collectively suggest that SUMO-2 conjugation plays a crucial regulatory role in protein synthesis. Thus, this report might contribute to the basic understanding of mammalian protein translation and sheds some new light on the role of SUMO in this process. © 2014 Chen et al

    Bis(2-oxoindolin-3-ylidene)-benzodifuran-dione-based D-A polymers for high-performance n-channel transistors

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    Conjugated polymers based on a bis(2-oxoindolin-3-ylidene)-benzodifuran-dione (BIBDF) unit displayed promising performances for their application in organic thin-film transistors (OTFTs). Herein, three new BIBDF-based donor-acceptor (D-A) polymers, containing thieno[3,2-b] thiophene (TT), (E)-2-(2-(thiophen- 2-yl)vinyl)thiophene (TVT) and (2-(thiophene-2-yl)alkynyl)thiophene (TAT) as donors, were synthesized and characterized. The results indicated that the donor unit plays important roles in affecting the absorption bands, HOMO levels, lamellar packing and pi-pi stacking distances of the BIBDF-based polymers. The OTFT devices based on the three polymers were fabricated, and their field-effect performance and environmental stability were also characterized. All three BIBDF based polymers showed good n-type field-effect characteristics. The PBIBDF-TT showed the highest electron mobility of 0.65 cm(2) V-1 s(-1) and the best environmental stability, while the PBIBDF-TAT showed the lowest electron mobility of 0.13 cm(2) V-1 s(-1). The corresponding crystalline structures and morphologies revealed that the PBIBDF-TT and PBIBDF-TVT showed close pi-pi distances and long-range ordered, lamellar crystalline structures both of which contributed to the high charge carrier mobility. The PBIBDF-TAT with close pi-pi distances but poor crystalline structures showed miserable performance. Overall, this work showed the correlation of the microstructures and properties of BIBDF-based polymers, and the field-effect performances can be effectively optimized by introducing different donor units.open112320sciescopu

    The reactivity ratios of group transfer copolymerization of acrylonitrile with methacrylates

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    Random copolymerization have been performed for three binary systems using 1-methoxy-2-methyl-1-trimethylsilyloxy propene(initiator) and tetrabutylammonium bibenzoate(catalyst) in tetrahydrofuran solution. The copolymer compositions were determined by elementary analysis for nitrogen and the results evaluated by the Kelen-Tudos method, The monomer pairs concerned are (1) acrylonitrile(AN) and methyl methacrylate(MMA), (2) AN and ethyl methacrylate(EMA), (3) AN and butyl methacrylate(BMA), The reactivity ratios determined in this study are: (1) r(AN)=10.22, r(MMA)=0.07; (2)r(AN)= 5.68, r(EMA)=0.16; (3) r(AN)=8.59, r(BMA)=0.09

    Entomopathogenic Fungi on Hemiberlesia pitysophila

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    Hemiberlesia pitysophila Takagi is an extremely harmful exotic insect in forest to Pinus species, including Pinus massoniana. Using both morphological taxonomy and molecular phylogenetics, we identified 15 strains of entomogenous fungi, which belong to 9 genera with high diversities. Surprisingly, we found that five strains that were classified as species of Pestalotiopsis, which has been considered plant pathogens and endophytes, were the dominant entomopathogenic fungus of H. pitysophila. Molecular phylogenetic tree established by analyzing sequences of ribosomal DNA internal transcribed spacer showed that entomopathogenic Pestalotiopsis spp. were similar to plant Pestalotiopsis, but not to other pathogens and endophytes of its host plant P. massoniana. We were the first to isolate entomopathogenic Pestalotiopsis spp. from H. pitysophila. Our findings suggest a potential and promising method of H. pitysophila bio-control
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