296 research outputs found

    Quantum Monte Carlo with very large multideterminant wavefunctions

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    An algorithm to compute efficiently the first two derivatives of (very) large multideterminant wavefunctions for quantum Monte Carlo calculations is presented. The calculation of determinants and their derivatives is performed using the Sherman-Morrison formula for updating the inverse Slater matrix. An improved implementation based on the reduction of the number of column substitutions and on a very efficient implementation of the calculation of the scalar products involved is presented. It is emphasized that multideterminant expansions contain in general a large number of identical spin-specific determinants: for typical configuration interaction-type wavefunctions the number of unique spin-specific determinants NdetσN_{\rm det}^\sigma (σ=↑,↓\sigma=\uparrow,\downarrow) with a non-negligible weight in the expansion is of order O(Ndet){\cal O}(\sqrt{N_{\rm det}}). We show that a careful implementation of the calculation of the NdetN_{\rm det}-dependent contributions can make this step negligible enough so that in practice the algorithm scales as the total number of unique spin-specific determinants,   Ndet↑+Ndet↓\; N_{\rm det}^\uparrow + N_{\rm det}^\downarrow, over a wide range of total number of determinants (here, NdetN_{\rm det} up to about one million), thus greatly reducing the total computational cost. Finally, a new truncation scheme for the multideterminant expansion is proposed so that larger expansions can be considered without increasing the computational time. The algorithm is illustrated with all-electron Fixed-Node Diffusion Monte Carlo calculations of the total energy of the chlorine atom. Calculations using a trial wavefunction including about 750 000 determinants with a computational increase of ∼\sim 400 compared to a single-determinant calculation are shown to be feasible.Comment: 9 pages, 3 figure

    Best Available Techniques (BAT) Reference Document for the Production of Chlor-alkali. Industrial Emissions Directive 2010/75/EU (Integrated Pollution Prevention and Control)

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    The BAT reference document entitled ‘Production of Chlor-alkali’ forms part of a series presenting the results of an exchange of information between EU Member States, the industries concerned, non-governmental organisations promoting environmental protection, and the Commission, to draw up, review and, where necessary, update BAT reference documents as required by Article 13(1) of the Directive 2010/75/EU on industrial emissions. This document is published by the European Commission pursuant to Article 13(6) of the Directive. This BREF for the production of chlor-alkali covers certain industrial activities specified in Sections 4.2(a) and 4.2(c) of Annex I to Directive 2010/75/EU, namely the production of chlor-alkali chemicals (chlorine, hydrogen, potassium hydroxide and sodium hydroxide) by the electrolysis of brine. In particular, this document covers the following processes and activities: - the storage of salt; - the preparation, purification and resaturation of brine; - the electrolysis of brine; - the concentration, purification, storage and handling of sodium/potassium hydroxide; - the cooling, drying, purification, compression, liquefaction, storage and handling of chlorine; - the cooling, purification, compression, storage and handling of hydrogen; - the conversion of mercury cell plants to membrane cell plants; - the decommissioning of mercury cell plants; - the remediation of chlor-alkali production sites. Important issues for the implementation of Directive 2010/75/EU in the chlor-alkali industry are the conversion and decommissioning of mercury cell plants, the conversion of asbestos diaphragm cell plants and the use of non-asbestos diaphragms, electricity consumption, and emissions of chlorine to air and water. The BREF contains seven chapters. Chapters 1 and 2 provide general information on the chlor-alkali industry and on the industrial processes and techniques used within this sector. Chapter 3 provides data and information concerning the environmental performance of installations in terms of current emissions, consumption of raw materials, water and energy, and generation of waste. Chapter 4 describes the techniques to prevent or reduce the environmental impact of installations in the sector. In Chapter 5 the BAT conclusions, as defined in Article 3(12) of the Directive, are presented for the chlor-alkali industry. Chapters 6 and 7 are dedicated to emerging techniques as well as to concluding remarks and recommendations for future work in the sector, respectively.JRC.J.5-Sustainable Production and Consumptio

    Best Available Techniques (BAT) Reference Document for the Food, Drink and Milk Industries. Industrial Emissions Directive 2010/75/EU (Integrated Pollution Prevention and Control)

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    The Best Available Techniques (BAT) Reference Document (BREF) for the Food, Drink and Milk Industries is part of a series of documents presenting the results of an exchange of information between EU Member States, the industries concerned, non-governmental organisations promoting environmental protection, and the Commission, to draw up, review and – where necessary – update BAT reference documents as required by Article 13(1) of Directive 2010/78/EU on Industrial Emissions (the Directive). This document is published by the European Commission pursuant to Article 13(6) of the Directive. The BREF for the Food, Drink and Milk Industries covers the treatment and processing, other than exclusively packaging, of the animal and/or vegetable raw materials, whether previously processed or unprocessed, intended for the production of food or feed, as specified in Section 6.4 (b) of Annex I to Directive 2010/75/EU. Important issues for the implementation of Directive 2010/75/EU in the food, drink and milk (FDM) sector are emissions to water, energy and water consumption. Chapter 1 provides general information on the FDM sector and on the industrial processes and techniques used within this sector. Chapter 2 provides information on the common industrial processes, abatement systems and general techniques that are used across the FDM sector. General techniques to consider in the determination of BAT (i.e. those techniques to consider that are widely applied in the FDM sector) are reported in Chapter 2. Chapters 3 to 15 give the applied processes, current emission and consumption levels, techniques to consider in the determination of BAT and emerging techniques for the FDM sectors that are covered by these chapters. Chapter 16 provides thumbnail descriptions of additional FDM sectors, for which a data collection via questionnaires has not been carried out. Chapter 17 presents the BAT conclusions as defined in Article 3(12) of the Directive, both general and sector-specific. Concluding remarks and recommendations for future work are presented in Chapter 18.JRC.B.5-Circular Economy and Industrial Leadershi

    Draft genome sequence of Raoultella ornithinolytica P079F W, isolated from the feces of a preterm infant

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    Here, we describe the draft genome sequence of Raoultella ornithinolytica P079F W, isolated from the feces of an infant residing in a neonatal intensive care unit during an ongoing study to characterize the neonate gut microbiota. P079F W will be used in studies investigating the role of the microbiome in neonatal infections

    Using Fine Resolution Orthoimagery and Spatial Interpolation to Rapidly Map Turf Grass in Suburban Massachusetts

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    This paper explores the use of spatial interpolative methods in conjunction with object based image analysis to estimate turf grass land cover quantity and allocation in Greater Boston, Massachusetts, USA. The goal is to learn how accurately turf grass can be estimated if only a limited portion of the study area is mapped. First, turf grass land cover is mapped at the 0.5 m resolution across the entire Plum Island Ecosystems (PIE) Long Term Ecological Research (LTER) site, a 1143-km2 area. Second, the turf grass map is aggregated into 120 m cells (N = 84,661). Third, a random sample of these 120 m cells are selected to generate an estimate of the unselected cells using four estimation methods - Inverse Distance Weighting, Kriging, Polygonal Interpolation, and Mean Estimation. The difference between known and estimated values is recorded using 120 m cell and census block group stratifications. This process is repeated 500 times for sample sizes of 2.5%, 5.0%, 7.5% and 10.0% of the study area, for a total of 2000 iterations. The average error statistics are reported by sample size, strata, and estimation method. Inverse distance weighting performed best in terms of total error across all sample sizes. It was found that by mapping only 2.5% of the study area, all four methods outperformed a recently published approach to estimating turf grass in terms of overall error

    eggNOG 6.0: enabling comparative genomics across 12 535 organisms

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    The eggNOG (evolutionary gene genealogy Non-supervised Orthologous Groups) database is a bioinformatics resource providing orthology data and comprehensive functional information for organisms from all domains of life. Here, we present a major update of the database and website (version 6.0), which increases the number of covered organisms to 12 535 reference species, expands functional annotations, and implements new functionality. In total, eggNOG 6.0 provides a hierarchy of over 17M orthologous groups (OGs) computed at 1601 taxonomic levels, spanning 10 756 bacterial, 457 archaeal and 1322 eukaryotic organisms. OGs have been thoroughly annotated using recent knowledge from functional databases, including KEGG, Gene Ontology, UniProtKB, BiGG, CAZy, CARD, PFAM and SMART. eggNOG also offers phylogenetic trees for all OGs, maximising utility and versatility for end users while allowing researchers to investigate the evolutionary history of speciation and duplication events as well as the phylogenetic distribution of functional terms within each OG. Furthermore, the eggNOG 6.0 website contains new functionality to mine orthology and functional data with ease, including the possibility of generating phylogenetic profiles for multiple OGs across species or identifying single-copy OGs at custom taxonomic levels. eggNOG 6.0 is available at http://eggnog6.embl.de

    Effect of incorrect use of dry powder inhalers on management of patients with asthma and COPD

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    SummaryBackgroundIncorrect usage of inhaler devices might have a major influence on the clinical effectiveness of the delivered drug. This issue is poorly addressed in management guidelines.MethodsThis article presents the results of a systematic literature review of studies evaluating incorrect use of established dry powder inhalers (DPIs) by patients with asthma or chronic obstructive pulmonary disease (COPD).ResultsOverall, we found that between 4% and 94% of patients, depending on the type of inhaler and method of assessment, do not use their inhalers correctly. The most common errors made included failure to exhale before actuation, failure to breath-hold after inhalation, incorrect positioning of the inhaler, incorrect rotation sequence, and failure to execute a forceful and deep inhalation. Inefficient DPI technique may lead to insufficient drug delivery and hence to insufficient lung deposition. As many as 25% of patients have never received verbal inhaler technique instruction, and for those that do, the quality and duration of instruction is not adequate and not reinforced by follow-up checks.ConclusionsThis review demonstrates that incorrect DPI technique with established DPIs is common among patients with asthma and COPD, and suggests that poor inhalation technique has detrimental consequences for clinical efficacy. Regular assessment and reinforcement of correct inhalation technique are considered by health professionals and caregivers to be an essential component of successful asthma management. Improvement of asthma and COPD management could be achieved by new DPIs that are easy to use correctly and are forgiving of poor inhalation technique, thus ensuring more successful drug delivery
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