1,271 research outputs found

    Multiscale theory of nonlinear wavepacket propagation in a planar optical waveguide

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    In this paper, the multiscale expansion formalism is applied for the first time, to our knowledge, in nonlinear planar optical waveguides. This formalism permits us to describe the linear and nonlinear propagation for both transverse electric and transverse magnetic modes. The modal field distributions and the nonlinear coefficient in the nonlinear Schrödinger equation are highlighted

    Polarization switching in a planar optical waveguide

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    The multiscale expansion formalism is applied to the study of nonlinear planar optical waveguides. It allows us to describe the linear and nonlinear propagation for both transverse electric and transverse magnetic modes, and the interaction between them. An accurate computation of the nonlinear self- and cross-phase modulation coefficients allows one to give account of the polarization switching which has been observed experimentally

    Susceptibility of influenza B viruses to neuraminidase inhibitors: findings from the first 4 years (2008–2012) of the global Influenza Resistance Information Study (IRIS)

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    Poster Session: Antiviral Drugs and ResistanceBackground: Type B influenza virus infections continue to account for a substantial proportion of clinical illness. Little is known about comparative disease profiles by virus lineage. A global observational trial (the Influenza Resistance Information Study or IRIS; NCT00884117) was initiated to study neuraminidase inhibitor (NAI) susceptibility and the clinical and virological course of influenza in treated and untreated patients. Materials and Methods: Patients in the northern and southern hemispheres (USA, France, Germany, Poland, Norway, Hong Kong, Australia) with influenza-like illness and/or a positive rapid influenza test result were enrolled. Throat/nasal swabs were performed on Days 1, 3 (self-swab), 6 and 10 and tested for influenza A and B viruses by RT-PCR. Influenzapositive samples collected on Days 1, 6 or 10 were cultured and subsequently sequenced (HA and NA) and phenotypically tested for NAI susceptibility. The lineage of B viruses was determined from sequencing. Clinical information, including the scoring of seven influenza symptoms (scale: 0 [absent], 1 [mild], 2 [moderate], 3 [severe]), was recorded on diary cards by the patient or the patient’s legal guardian (Days 1–12). Symptoms were also assessed by the investigator at each visit. The decision to prescribe an NAI was left to the physician’s discretion. Results: In the first 4 years of IRIS (December 2008 to March 2012), 2262 influenza-positive (RT-PCR) patients were enrolled, of whom 697 presented with a type B influenza virus infection (564 Victoria, 98 Yamagata, 35 undetermined lineage). Most type B patients (402; 58%) were children aged < 13 years. A total of 330 (47%) type B patients were treated with oseltamivir (as monotherapy) within 2 days of symptom onset; a further 26 started oseltamivir 2 days after symptom onset. Eleven patients received zanamivir, one received amantadine and another received rimantidine. A total of 328 (47%) did not receive any influenza antiviral. Symptoms were mild to moderate on Day 1 (mean total score: 12.8, treated; 12.9, untreated), and the mean temperature on Day 1 was 38.2°C. All viruses obtained at baseline or postbaseline were susceptible to NAIs: mean (SD) IC50 values for oseltamivir were 4.8 nM (2.5 nM) and 5.5 nM (2.3 nM) for the Victoria and Yamagata viruses, respectively; the corresponding values for zanamivir were 2.0 nM (1.4 nM) and 2.9 nM (1.6 nM), respectively. No known NAI resistance mutations were detected by NA or HA population sequencing. The proportion of RT-PCR–positive patients on Day 6 was 130/309 (42.1%) for patients treated with oseltamivir and 152/312 (48.7%) for untreated patients. In Kaplan–Meier analyses, no significant differences in median time to influenza RNA clearance were found between oseltamivir-treated and -untreated patients, either in adults or children. The time to symptom resolution (all symptom scores ≤ 1) was 5 days (95% CI, 4–5 days) in oseltamivir-treated children and 6 days (95% CI, 5–6 days) in untreated children (P = .026), but no significant difference in symptom resolution time was found in adults (Kaplan–Meier analysis). Conclusions: Analysis of type B influenza viruses obtained globally between 2008 and 2012 showed that all pre-treatment B/Victoria and B/Yamagata viruses were susceptible to oseltamivir and zanamivir. Moreover, no resistant viruses were detected during treatment. Given the non-randomised design of this study, no definitive conclusions can be drawn with regard to the clinical benefit of oseltamivir in patients infected with type B influenza viruses.published_or_final_versio

    ENGINEERING METHODOLOGY FOR ORGANISATION NETWORK

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    This paper presents the key features of an engineering methodology dedicated to Organisation Networks. This methodology constitutes one of the elements of a full engineering framework developed through a PhD research thesis. The authors mainly focus hereafter on specifying the &quot;design&quot; and &quot;preliminary engineering&quot; activities of the engineering procedure. The methodology is illustrated on a case study from the sector of metallurgical industry

    The BioGRID Interaction Database: 2011 update

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    The Biological General Repository for Interaction Datasets (BioGRID) is a public database that archives and disseminates genetic and protein interaction data from model organisms and humans (http://www.thebiogrid.org). BioGRID currently holds 347 966 interactions (170 162 genetic, 177 804 protein) curated from both high-throughput data sets and individual focused studies, as derived from over 23 000 publications in the primary literature. Complete coverage of the entire literature is maintained for budding yeast (Saccharomyces cerevisiae), fission yeast (Schizosaccharomyces pombe) and thale cress (Arabidopsis thaliana), and efforts to expand curation across multiple metazoan species are underway. The BioGRID houses 48 831 human protein interactions that have been curated from 10 247 publications. Current curation drives are focused on particular areas of biology to enable insights into conserved networks and pathways that are relevant to human health. The BioGRID 3.0 web interface contains new search and display features that enable rapid queries across multiple data types and sources. An automated Interaction Management System (IMS) is used to prioritize, coordinate and track curation across international sites and projects. BioGRID provides interaction data to several model organism databases, resources such as Entrez-Gene and other interaction meta-databases. The entire BioGRID 3.0 data collection may be downloaded in multiple file formats, including PSI MI XML. Source code for BioGRID 3.0 is freely available without any restrictions

    Analysis and quantification of the diversities of aerosol life cycles within AeroCom

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    Simulation results of global aerosol models have been assembled in the framework of the AeroCom intercomparison exercise. In this paper, we analyze the life cycles of dust, sea salt, sulfate, black carbon and particulate organic matter as simulated by sixteen global aerosol models. The diversities among the models for the sources and sinks, burdens, particle sizes, water uptakes, and spatial dispersals have been established. These diversities have large consequences for the calculated radiative forcing and the aerosol concentrations at the surface. The AeroCom all-models-average emissions are dominated by the mass of sea salt (SS), followed by dust (DU), sulfate (SO_4), particulate organic matter (POM), and finally black carbon (BC). Interactive parameterizations of the emissions and contrasting particles sizes of SS and DU lead generally to higher diversities of these species, and for total aerosol. The lower diversity of the emissions of the fine aerosols, BC, POM, and SO_4, is due to the use of similar emission inventories, and does therefore not necessarily indicate a better understanding of their sources. The diversity of SO_4-sources is mainly caused by the disagreement on depositional loss of precursor gases and on chemical production. The diversities of the emissions are passed on to the burdens, but the latter are also strongly affected by the model-specific treatments of transport and aerosol processes. The burdens of dry masses decrease from largest to smallest: DU, SS, SO_4, POM, and BC. The all-models-average residence time is shortest for SS with about half a day, followed by S_O4 and DU with four days, and POM and BC with six and seven days, respectively. The wet deposition rate is controlled by the solubility and increases from DU, BC, POM to SO_4 and SS. It is the dominant sink for SO_4, BC, and POM, and contributes about one third to the total removal rate coefficients of SS and DU species. For SS and DU we find high diversities for the removal rate coefficients and deposition pathways. Models do neither agree on the split between wet and dry deposition, nor on that between sedimentation and turbulent dry Deposition. We diagnose an extremely high diversity for the uptake of ambient water vapor that influences the particle size and thus the sink rate coefficients. Furthermore, we find little agreement among the model results for the partitioning of wet removal into scavenging by convective and stratiform rain. Large differences exist for aerosol dispersal both in the vertical and in the horizontal direction. In some models, a minimum of total aerosol concentration is simulated at the surface. Aerosol dispersal is most pronounced for SO4 and BC and lowest for SS. Diversities are higher for meridional than for vertical dispersal, they are similar for a given species and highest for SS and DU. For these two components we do not find a correlation between vertical and meridional aerosol dispersal. In addition the degree of dispersals of SS and DU is not related to their residence times. SO_4, BC, and POM, however, show increased meridional dispersal in models with larger vertical dispersal, and dispersal is larger for longer simulated residence times

    An AeroCom initial assessment – optical properties in aerosol component modules of global models

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    The AeroCom exercise diagnoses multi-component aerosol modules in global modeling. In an initial assessment simulated global distributions for mass and mid-visible aerosol optical thickness (aot) were compared among 20 different modules. Model diversity was also explored in the context of previous comparisons. For the component combined aot general agreement has improved for the annual global mean. At 0.11 to 0.14, simulated aot values are at the lower end of global averages suggested by remote sensing from ground (AERONET ca. 0.135) and space (satellite composite ca. 0.15). More detailed comparisons, however, reveal that larger differences in regional distribution and significant differences in compositional mixture remain. Of particular concern are large model diversities for contributions by dust and carbonaceous aerosol, because they lead to significant uncertainty in aerosol absorption (aab). Since aot and aab, both, influence the aerosol impact on the radiative energy-balance, the aerosol (direct) forcing uncertainty in modeling is larger than differences in aot might suggest. New diagnostic approaches are proposed to trace model differences in terms of aerosol processing and transport: These include the prescription of common input (e.g. amount, size and injection of aerosol component emissions) and the use of observational capabilities from ground (e.g. measurements networks) or space (e.g. correlations between aerosol and clouds)

    Beyond paired quantum Hall states: parafermions and incompressible states in the first excited Landau level

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    The Pfaffian quantum Hall states, which can be viewed as involving pairing either of spin-polarized electrons or of composite fermions, are generalized by finding the exact ground states of certain Hamiltonians with k+1-body interactions, for all integers k > 0. The remarkably simple wavefunctions of these states involve clusters of k particles, and are related to correlators of parafermion currents in two-dimensional conformal field theory. The k=2 case is the Pfaffian. For k > 1, the quasiparticle excitations of these systems are expected to possess nonabelian statistics, like those of the Pfaffian. For k=3, these ground states have large overlaps with the ground states of the (2-body) Coulomb-interaction Hamiltonian for electrons in the first excited Landau level at total filling factors \nu=2+3/5, 2+2/5.Comment: 11 pages Revtex in two column format with 4 eps figures included in the M

    How to obtain lattices from (f,σ,δ)-codes via a generalization of Construction A

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    We show how cyclic (f,σ,δ)-codes over finite rings canonically induce a Z-lattice in RN by using certain quotients of orders in nonassociative division algebras defined using the skew polynomial f. This construction generalizes the one using certain σ-constacyclic codes by Ducoat and Oggier, which used quotients of orders in non-commutative associative division algebras defined by f, and can be viewed as a generalization of the classical Construction A for lattices from linear codes. It has the potential to be applied to coset coding, in particular to wire-tap coding. Previous results by Ducoat and Oggier are obtained as special cases

    The effect of harmonized emissions on aerosol properties in global models – an AeroCom experiment

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    The effects of unified aerosol sources on global aerosol fields simulated by different models are examined in this paper. We compare results from two AeroCom experiments, one with different (ExpA) and one with unified emissions, injection heights, and particle sizes at the source (ExpB). Surprisingly, harmonization of aerosol sources has only a small impact on the simulated diversity for aerosol burden, and consequently optical properties, as the results are largely controlled by model-specific transport, removal, chemistry (leading to the formation of secondary aerosols) and parameterizations of aerosol microphysics (e.g. the split between deposition pathways) and to a lesser extent on the spatial and temporal distributions of the (precursor) emissions. The burdens of black carbon and especially sea salt become more coherent in ExpB only, because the large ExpA diversity for these two species was caused by few outliers. The experiment also indicated that despite prescribing emission fluxes and size distributions, ambiguities in the implementation in individual models can lead to substantial differences. These results indicate the need for a better understanding of aerosol life cycles at process level (including spatial dispersal and interaction with meteorological parameters) in order to obtain more reliable results from global aerosol simulations. This is particularly important as such model results are used to assess the consequences of specific air pollution abatement strategies
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