68 research outputs found

    Gutzwiller density functional calculations of the electronic structure of FeAs-based superconductors: Evidence for a three-dimensional Fermi surface

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    The electronic structures of FeAs-compounds strongly depend on the Fe-As bonding, which can not be described successfully by the local density approximation (LDA). Treating the multi-orbital fluctuations from abab-initioinitio by LDA+Gutzwiller method, we are now able to predict the correct Fe-As bond-length, and find that Fe-As bonding-strength is 30% weaker, which will explain the observed "soft phonon". The bands are narrowed by a factor of 2, and the d3z2r2d_{3z^2-r^2} orbital is pushed up to cross the Fermi level, forming 3-dimensional Fermi surfaces, which suppress the anisotropy and the (π,π\pi,\pi) nesting. The inter-orbital Hund's coupling JJ rather than UU plays crucial roles to obtain these results.Comment: 4 pages, 4 figures, 1 tabl

    Near-field coupling and resonant cavity modes in plasmonic nanorod metamaterials

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    Plasmonic resonant cavities are capable of confining light at the nanoscale, resulting in both enhanced local electromagnetic fields and lower mode volumes. However, conventional plasmonic resonant cavities possess large Ohmic losses at metal-dielectric interfaces. Plasmonic near-field coupling plays a key role in a design of photonic components based on the resonant cavities because of the possibility to reduce losses. Here, we study the plasmonic near-field coupling in the silver nanorod metamaterials treated as resonant nanostructured optical cavities. Reflectance measurements reveal the existence of multiple resonance modes of the nanorod metamaterials, which is consistent with our theoretical analysis. Furthermore, our numerical simulations show that the electric field at the longitudinal resonances forms standing waves in the nanocavities due to the near-field coupling between the adjacent nanorods, and a new hybrid mode emerges due to a coupling between nanorods and a gold-film substrate. We demonstrate that this coupling can be controlled by changing the gap between the silver nanorod array and gold substrate

    Use of a non-homologous end-joining-deficient strain (delta-ku70) of the biocontrol fungus Trichoderma virens to investigate the function of the laccase gene lcc1 in sclerotia degradation

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    The aim of this study was to apply a generated Δtku70 strain with increased homologous recombination efficiency from the mycoparasitic fungus Trichoderma virens for studying the involvement of laccases in the degradation of sclerotia of plant pathogenic fungi. Inactivation of the non-homologous end-joining pathway has become a successful tool in filamentous fungi to overcome poor targeting efficiencies for genetic engineering. Here, we applied this principle to the biocontrol fungus T. virens, strain I10, by deleting its tku70 gene. This strain was subsequently used to delete the laccase gene lcc1, which we found to be expressed after interaction of T. virens with sclerotia of the plant pathogenic fungi Botrytis cinerea and Sclerotinia sclerotiorum. Lcc1 was strongly upregulated at early colonization of B. cinerea sclerotia and steadily induced during colonization of S. sclerotiorum sclerotia. The Δtku70Δlcc1 mutant was altered in its ability to degrade the sclerotia of B. cinerea and S. sclerotiorum. Interestingly, while the decaying ability for B. cinerea sclerotia was significantly decreased, that to degrade S. sclerotiorum sclerotia was even enhanced, suggesting the operation of different mechanisms in the mycoparasitism of these two types of sclerotia by the laccase LCC1

    Biology and biotechnology of Trichoderma

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    Fungi of the genus Trichoderma are soilborne, green-spored ascomycetes that can be found all over the world. They have been studied with respect to various characteristics and applications and are known as successful colonizers of their habitats, efficiently fighting their competitors. Once established, they launch their potent degradative machinery for decomposition of the often heterogeneous substrate at hand. Therefore, distribution and phylogeny, defense mechanisms, beneficial as well as deleterious interaction with hosts, enzyme production and secretion, sexual development, and response to environmental conditions such as nutrients and light have been studied in great detail with many species of this genus, thus rendering Trichoderma one of the best studied fungi with the genome of three species currently available. Efficient biocontrol strains of the genus are being developed as promising biological fungicides, and their weaponry for this function also includes secondary metabolites with potential applications as novel antibiotics. The cellulases produced by Trichoderma reesei, the biotechnological workhorse of the genus, are important industrial products, especially with respect to production of second generation biofuels from cellulosic waste. Genetic engineering not only led to significant improvements in industrial processes but also to intriguing insights into the biology of these fungi and is now complemented by the availability of a sexual cycle in T. reesei/Hypocrea jecorina, which significantly facilitates both industrial and basic research. This review aims to give a broad overview on the qualities and versatility of the best studied Trichoderma species and to highlight intriguing findings as well as promising applications

    The Battle of the Water Networks II (BWN-II)

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    The Battle of the Water Networks II (BWN-II) is the latest of a series of competitions related to the design and operation of water distribution systems (WDSs) undertaken within the Water Distribution Systems Analysis (WDSA) Symposium series. The BWN-II problem specification involved a broadly defined design and operation problem for an existing network that has to be upgraded for increased future demands, and the addition of a new development area. The design decisions involved addition of new and parallel pipes, storage, operational controls for pumps and valves, and sizing of backup power supply. Design criteria involved hydraulic, water quality, reliability, and environmental performance measures. Fourteen teams participated in the Battle and presented their results at the 14th Water Distribution Systems Analysis (WDSA 2012) conference in Adelaide, Australia, September 2012. This paper summarizes the approaches used by the participants and the results they obtained. Given the complexity of the BWN-II problem and the innovative methods required to deal with the multi-objective, high dimensional and computationally demanding nature of the problem, this paper represents a snap-shot of state of the art methods for the design and operation of water distribution systems. A general finding of this paper is that there is benefit in using a combination of heuristic engineering experience and sophisticated optimization algorithms when tackling complex real-world water distribution system design problems.Angela Marchi...Angus R. Simpson, Aaron C. Zecchin, Holger R. Maier...Christopher Stokes, Wenyan Wu, Graeme C. Dandy...et al

    The Battle of the Water Networks II (BWN-II)

    Get PDF
    The Battle of the Water Networks II (BWN-II) is the latest of a series of competitions related to the design and operation of water distribution systems (WDSs) undertaken within the Water Distribution Systems Analysis (WDSA) Symposium series. The BWN-II problem specification involved a broadly defined design and operation problem for an existing network that has to be upgraded for increased future demands, and the addition of a new development area. The design decisions involved addition of new and parallel pipes, storage, operational controls for pumps and valves, and sizing of backup power supply. Design criteria involved hydraulic, water quality, reliability, and environmental performance measures. Fourteen teams participated in the Battle and presented their results at the 14th Water Distribution Systems Analysis (WDSA 2012) conference in Adelaide, Australia, September 2012. This paper summarizes the approaches used by the participants and the results they obtained. Given the complexity of the BWN-II problem and the innovative methods required to deal with the multi-objective, high dimensional and computationally demanding nature of the problem, this paper represents a snap-shot of state of the art methods for the design and operation of water distribution systems. A general finding of this paper is that there is benefit in using a combination of heuristic engineering experience and sophisticated optimization algorithms when tackling complex real-world water distribution system design problems.Angela Marchi...Angus R. Simpson, Aaron C. Zecchin, Holger R. Maier...Christopher Stokes, Wenyan Wu, Graeme C. Dandy...et al

    Public perceptions of physical and virtual water in China

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    Ensuring access to water is one of the United Nations' Sustainable Development Goals. Water demand management, which has emerged as an important approach to secure water supply, should be underpinned by a good understanding of how the public perceive their use of water. In this study, we investigated public perceptions of physical and virtual water in China through online surveys using the multi-level regression models (two-level models). Based on 3262 responses, we found that overall, participants underestimated water uses and differences between water uses (daily potable water of an adult, shower, toilet flushing, etc.). Most participants did not possess the knowledge of virtual water embedded in their daily consumed products. Individuals showed rather different perceptions in water use, which were affected by gender, age, education, resource and environmental attitude, water saving behaviors, water price and residential water source. In combination with previous findings in the United States, we concluded that despite different natural water endowment and socio-economic and cultural conditions, underestimation of water use is commonly shared by Chinese and Americans. This highlights a need of strengthening public knowledge of water use. The results are useful in informing policies to enhance the public's awareness of water use towards improved water demand management
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