752 research outputs found

    Second-order electronic correlation effects in a one-dimensional metal

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    The Pariser-Parr-Pople (PPP) model of a single-band one-dimensional (1D) metal is studied at the Hartree-Fock level, and by using the second-order perturbation theory of the electronic correlation. The PPP model provides an extension of the Hubbard model by properly accounting for the long-range character of the electron-electron repulsion. Both finite and infinite version of the 1D-metal model are considered within the PPP and Hubbard approximations. Calculated are the second-order electronic-correlation corrections to the total energy, and to the electronic-energy bands. Our results for the PPP model of 1D metal show qualitative similarity to the coupled-cluster results for the 3D electron-gas model. The picture of the 1D-metal model that emerges from the present study provides a support for the hypothesis that the normal metallic state of the 1D metal is different from the ground state.Comment: 21 pages, 16 figures; v2: small correction in title, added 3 references, extended and reformulated a few paragraphs (detailed information at the end of .tex file); added color to figure

    A Multi‐layer Device for Light‐triggered Hydrogen Production from Alkaline Methanol

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    Hydrogen production from methanol has attracted substantial interest because of the clean combustion of hydrogen and the convenience of methanol in storage and transportation. However, it requires high-temperature and high-pressure conditions to reform methanol with water to hydrogen with high turnover frequency (TOF, e.g. 10 4 moles of hydrogen per mole of Pt per hour). Here we show that hydrogen can be produced from alkaline methanol on a light-triggered multi-layer system with a very high hydrogen evolution rate up to ~1 μmol/s under the illumination of a standard Pt-decorated carbon nitride. The system can achieve a remarkable TOF up to 1.8×10 6 moles of hydrogen per mole of Pt per hour under mild conditions. The total turnover number (TTN) of 470,000 measured over 38 hours is among the highest reported. In addition, the system does not lead to any CO x emissions, hence it could feed clean hydrogen to fuel cells. In contrast to a slurry system, we show that the proposed multi-layer system avoids particle aggregation and leads to the effective use of light and Pt active sites. The performance is also attributed to the light-triggered reforming of alkaline methanol. This notable performance is a promising step toward practical light-driven hydrogen generation

    Diversity of gut microflora is required for the generation of B cell with regulatory properties in a skin graft model

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    B cells have been reported to promote graft rejection through alloantibody production. However, there is growing evidence that B cells can contribute to the maintenance of tolerance. Here, we used a mouse model of MHC-class I mismatched skin transplantation to investigate the contribution of B cells to graft survival. We demonstrate that adoptive transfer of B cells prolongs skin graft survival but only when the B cells were isolated from mice housed in low sterility "conventional" (CV) facilities and not from mice housed in pathogen free facilities (SPF). However, prolongation of skin graft survival was lost when B cells were isolated from IL-10 deficient mice housed in CV facilities. The suppressive function of B cells isolated from mice housed in CV facilities correlated with an anti-inflammatory environment and with the presence of a different gut microflora compared to mice maintained in SPF facilities. Treatment of mice in the CV facility with antibiotics abrogated the regulatory capacity of B cells. Finally, we identified transitional B cells isolated from CV facilities as possessing the regulatory function. These findings demonstrate that B cells, and in particular transitional B cells, can promote prolongation of graft survival, a function dependent on licensing by gut microflora

    Civillity in the Legal Profession: A Survey of the Texas Judiciary.

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    Abstract Forthcoming

    A Historical Perspective of Bladderworts (Utricularia): Traps, Carnivory and Body Architecture

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    The genus Utricularia includes around 250 species of carnivorous plants, commonly known as bladderworts. The generic name Utricularia was coined by Carolus Linnaeus in reference to the carnivorous organs (Utriculus in Latin) present in all species of the genus. Since the formal proposition by Linnaeus, many species of Utricularia were described, but only scarce information about the biology for most species is known. All Utricularia species are herbs with vegetative organs that do not follow traditional models of morphological classification. Since the formal description of Utricularia in the 18th century, the trap function has intrigued naturalists. Historically, the traps were regarded as floating organs, a common hypothesis that was maintained by different botanists. However, Charles Darwin was most likely the first naturalist to refute this idea, since even with the removal of all traps, the plants continued to float. More recently, due mainly to methodological advances, detailed studies on the trap function and mechanisms could be investigated. This review shows a historical perspective on Utricularia studies which focuses on the traps and body organization

    Civillity in the Legal Profession: A Survey of the Texas Judiciary.

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    Abstract Forthcoming

    Floral micromorphology of the bird-pollinated carnivorous plant species Utricularia menziesii R.Br. (Lentibulariaceae)

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    Made available in DSpace on 2019-10-06T16:15:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-01• Background and Aims Bird pollination is rare among species in the genus Utricularia, and has evolved independently in two lineages of this genus. In Western Australia, the Western Spinebill, Acanthorhynchus superciliosus, visits flowers of Utricularia menziesii (section Pleiochasia: subgenus Polypompholyx). This study aimed to examine the micromorphology of U. menziesii flowers to assess traits that might be linked to its pollination strategy. • Methods Light microscopy, histochemistry and scanning electron microscopy were used. Nectar sugar composition was analysed using high-performance liquid chromatography. • Key Results The flowers of U. menziesii fulfil many criteria that characterize bird-pollinated flowers: red colour, a large, tough nectary spur that can withstand contact with a hard beak, lack of visual nectar guides and fragrance. Trichomes at the palate and throat may act as tactile signals. Spur nectary trichomes did not form clearly visible patches, but were more frequently distributed along vascular bundles, and were small and sessile. Each trichome comprised a single basal cell, a unicellular short pedestal cell (barrier cell) and a multicelled head. These trichomes were much smaller than those of the U. vulgaris allies. Hexose-dominated nectar was detected in flower spurs. Fructose and glucose were present in equal quantities (43 ± 3.6 and 42 ± 3.6 g L-1). Sucrose was only detected in one sample, essentially at the limit of detection for the method used. This type of nectar is common in flowers pollinated by passerine perching birds. • Conclusions The architecture of nectary trichomes in U. menziesii was similar to that of capitate trichomes of insect-pollinated species in this genus; thus, the most important specializations to bird pollination were flower colour (red), and both spur shape and size modification. Bird pollination is probably a recent innovation in the genus Utricularia, subgenus Polypompholyx, and is likely to have evolved from bee-pollinated ancestors.Department of Plant Cytology and Embryology Jagiellonian University in Kraków, 9 Gronostajowa St.Faculty of Biology University of Warsaw Botanic Garden, Al. Ujazdowskie 4Department of Animal Histology and Embryology University of Silesia in Katowice, 9 Bankowa St.School of Biological Sciences University of Western Australia (M084), 35 Stirling HighwayDepartamento de Biologia Aplicada à Agropecuária Faculdade de Ciências Agrárias E Veterinárias Universidade Estadual Paulista (Unesp)Faculty of Science School of Biological Sciences University of AdelaideUnit of Botany and Plant Physiology Institute of Plant Biology and Biotechnology University of Agriculture in Kraków, 29 Listopada 54 StreetDepartamento de Biologia Aplicada à Agropecuária Faculdade de Ciências Agrárias E Veterinárias Universidade Estadual Paulista (Unesp

    Cherenkov Telescope Array Data Management

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    Very High Energy gamma-ray astronomy with the Cherenkov Telescope Array (CTA) is evolving towards the model of a public observatory. Handling, processing and archiving the large amount of data generated by the CTA instruments and delivering scientific products are some of the challenges in designing the CTA Data Management. The participation of scientists from within CTA Consortium and from the greater worldwide scientific community necessitates a sophisticated scientific analysis system capable of providing unified and efficient user access to data, software and computing resources. Data Management is designed to respond to three main issues: (i) the treatment and flow of data from remote telescopes; (ii) "big-data" archiving and processing; (iii) and open data access. In this communication the overall technical design of the CTA Data Management, current major developments and prototypes are presented.Comment: 8 pages, 2 figures, In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions at arXiv:1508.0589
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