1,030 research outputs found

    Boundary quantum critical phenomena with entanglement renormalization

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    We extend the formalism of entanglement renormalization to the study of boundary critical phenomena. The multi-scale entanglement renormalization ansatz (MERA), in its scale invariant version, offers a very compact approximation to quantum critical ground states. Here we show that, by adding a boundary to the scale invariant MERA, an accurate approximation to the critical ground state of an infinite chain with a boundary is obtained, from which one can extract boundary scaling operators and their scaling dimensions. Our construction, valid for arbitrary critical systems, produces an effective chain with explicit separation of energy scales that relates to Wilson's RG formulation of the Kondo problem. We test the approach by studying the quantum critical Ising model with free and fixed boundary conditions.Comment: 8 pages, 12 figures, for a related work see arXiv:0912.289

    Results on Argentine (Argentinaspp.), Bluemouth (Helicolenus dactylopterus), Greater forkbeard (Phycis blennoides), Spanish ling (Molva macrophthalma) and ling (Molva molva) from 2014 Porcupine Bank (NE Atlantic) survey

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    This working document presents the results on four of the most significant deep fish species of the last Porcupine Spanish survey carried in 2014, as well as it updates previous documents presented with the information on the fourteen years (2001-2014) of the Spanish bottom trawl survey on the Porcupine Bank. The document presents total abundances in weight, length frequencies and geographical distributions for Argentinaspp. (mostly A. silus, results on proportions by Argentine species distribution in last surveys are provided), Bluemouth (Helicolenus dactylopterus), Greater fork-beard (Phycis blennoides) and Spanish ling (Molva macrophthalma). Argentinaspp. and Spanish ling presented a decrease in their abundances, whereas Bluemouth remained stable and Greater forkbeard increased slightly. In terms of recruitment 2014 showed larger values than previous years for A. sphyraena, Helicolenus dactylopterusand Molva macrophtalmabut weaker for Phycis blennoides, and A silus. Furthermore results for ling (Molva molva) on the Spanish Porcupine Bank survey are summarizedpresenting the results to the WG so their utility for the assessment could be considered.Versión de edito

    Results on main elasmobranch species captured during the 2001-2010 Porcupine Bank (NE Atlantic) bottom trawl surveys

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    This paper presents the results on nine of the most important elasmobranch fish species of the Porcupine bank Spanish surveys during the last decade (2001-2010). The main species in the captures in decreasing biomass order are: blackmouth catshark, birdbeak dogfish, knifetooth dogfish, velvet belly, lesser spotted dogfish, bluntnose sixgill shark, sandy ray, cuckoo ray and common skate. Manyof these species occupy mainly the deep areas covered in the survey,especially birdbeak dogfish, knifetooth dogfish and velvet belly. Less confined to deeper grounds are blackmouth catshark and sandy ray, while lesser spotted dogfish and cuckoo ray inhabit mainly the shallowergrounds close to the Irish shelf or the central mound in the bank. Length distributions of these species along the survey series are also presented and discussed. The few available data on siki sharks from the Porcupine bank survey are also summarized.Versión del edito

    Results on main cephalopods from the 2021 Spanish Ground Fish Survey on the Porcupine bank (NE Atlantic) (Division 7c and 7k)

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    This working document presents the results of the most significant cephalopods caught on the Porcupine Spanish Groundfish Survey (SP-PORC-Q3) in 2021. Biomass, abundance, geographical distribution and length frequencies for Eledone cirrhosa (horned octopus), Bathypolypus sponsalis (globose octopus), Todarodes sagittatus (European flying squid), Todaropsis eblanae (lesser flying squid), Loligo forbesi (veined squid), Illex coindetii (broadtail shortfin squid), Rossia macrosoma (stout bobtail squid) and other scarce cephalopods have been analysed. The species E. cirrhosa, R. macrosoma and L. forbesi increased in terms of biomass and abundance, especially R. macrosoma, reaching the highest biomass value in the time series, whereas T. sagitattus increased only in abundance terms but decreased slightly in biomass terms. In contrast, T. eblanae and B. sponsalis decreased strongly after the high values of the previous two years, as did I. coindetii. Most of the usually scarce species increased their biomass, with the exception of H. reversa

    Results on Merluccius merluccius (hake), Lophius budegassa (black anglerfish) and Lophius piscatorius (white anglerfish), Lepidorhombus boscii (four-spot megrim) and Lepidorhombus whiffiagonis (megrim) from the Spanish Ground Fish Survey on the Porcupine bank (NE Atlantic)

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    This working document presents the results of Merluccius merluccius (hake), Lophius budegassa (black anglerfish), Lophius piscatorius (white anglerfish), Lepidorhombus boscii (four-spot megrim) and Lepidorhombus whiffiagonis (megrim) caught on the Porcupine Spanish Groundfish Survey (SP-PORC-Q3) in 2020. Biomass, abundance, distribution and length frequency were analysed. Biomass indices of these target species decreased in this last survey and recruitment remained low

    Payao: a community platform for SBML pathway model curation

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    Summary: Payao is a community-based, collaborative web service platform for gene-regulatory and biochemical pathway model curation. The system combines Web 2.0 technologies and online model visualization functions to enable a collaborative community to annotate and curate biological models. Payao reads the models in Systems Biology Markup Language format, displays them with CellDesigner, a process diagram editor, which complies with the Systems Biology Graphical Notation, and provides an interface for model enrichment (adding tags and comments to the models) for the access-controlled community members

    Results on haddock (Melanogrammus aeglefinus), whiting (Merlangius merlangius) and Norway lobster (Nephrops norvegicus) from the Porcupine Bank Survey (NE Atlantic)

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    This working document presents the results on haddock (Melanogrammus aeglefinus), whiting (Merlangius merlangius) and Norway lobster (Nephrops norvegicus) caught in the Porcupine Spanish Groundfish Survey (SP-PORC-Q3) in 2020. Biomass, abundance, distribution and length frequency were analysed. M. aeglefinus remained low in the study area, although it increased slightly, but M. merlangius grew strongly and reached the highest values in the time series. No signs of recruits for neither two species were found. In addition, the incidental species Pleuronectes platessa and Solea solea were not found in 2020 and Pollachius pollachius has never been caught in the time series. The crustacean N. norvergicus fell sharply this last survey, although the mean individual weight was slightly higher than in previous years since 2016
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