416 research outputs found

    FGGE 4-dimensional data assimilation at ECMWF ( weather forecasts).

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    The 4-dimensional data-assimilation system used to produce the FGGE level III-b data set at the European Centre for Medium Range Weather Forecasts (ECMWF) is described. The system consists of a three-dimensional multivariate optimum interpolation, a nonlinear normal mode initialization, and associated automatic system for data checking. A 15-level model with a horizontal resolution of 1.875o is used for the dynamical assimilation. -from Author

    Hyphema. Part II. Diagnosis and Treatment

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    The clinical appearance of hyphema is variable and is influenced by the volume of blood and the amount of time erythrocytes are present in the anterior chamber. When hyphema is evident, a complete history should be obtained and a thorough physical examination performed to direct the initial selection of diagnostic tests. Secondary complications of hyphema include glaucoma, synechiae, cataract formation, blood-staining of the cornea, and blindness. Frequent measurement of intraocular pressure is recommended. The two primary management issues in animals with hyphema are prevention of secondary hemorrhage (by treating the underlying disease) and control of secondary glaucoma

    Hyphema. Part II. Diagnosis and Treatment

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    The clinical appearance of hyphema is variable and is influenced by the volume of blood and the amount of time erythrocytes are present in the anterior chamber. When hyphema is evident, a complete history should be obtained and a thorough physical examination performed to direct the initial selection of diagnostic tests. Secondary complications of hyphema include glaucoma, synechiae, cataract formation, blood-staining of the cornea, and blindness. Frequent measurement of intraocular pressure is recommended. The two primary management issues in animals with hyphema are prevention of secondary hemorrhage (by treating the underlying disease) and control of secondary glaucoma

    Hyphema. Part I. Pathophysiologic Considerations

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    Hemorrhage in the anterior chamber of the eye, or hyphema, results from a breakdown of the blood-ocular barrier (BOB) and is frequently associated with inflammation of the iris, ciliary body, or retina. Hyphema can also occur by retrograde blood flow into the anterior chamber via the aqueous humor drainage pathways without BOB breakdown. Hyphema attributable to blunt or perforating ocular trauma is more common than that resulting from endogenous causes. When trauma has been eliminated as a possible cause, it is prudent to assume that every animal with hyphema has a serious systemic disease until proven otherwise

    Measuring portfolio performance using a modified measure of risk

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    This paper reports the results of an investigation into the properties of a theoretical modification of beta proposed by Leland (1999) and based on earlier work of Rubinstein (1976). It is shown that when returns are elliptically symmetric, beta is the appropriate measure of risk and that there are other situations in which the modified beta will be similar to the traditional measure based on the capital asset pricing model. For the case where returns have a normal distribution, it is shown that the criterion either does not exist or reduces exactly to the conventional beta. It is therefore conjectured that the modified measure will only be useful for portfolios that have nonstandard return distributions which incorporate skewness. For such situations, it is shown how to estimate the measure using regression and how to compare the resulting statistic with a traditional estimated beta using Hotelling's test. An empirical study based on stocks from the FTSE350 does not find evidence to support the use of the new measure even in the presence of skewness.Journal of Asset Management (2007) 7, 388-403. doi:10.1057/palgrave.jam.225005

    Consumer credit information systems: A critical review of the literature. Too little attention paid by lawyers?

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    This paper reviews the existing literature on consumer credit reporting, the most extensively used instrument to overcome information asymmetry and adverse selection problems in credit markets. Despite the copious literature in economics and some research in regulatory policy, the legal community has paid almost no attention to the legal framework of consumer credit information systems, especially within the context of the European Union. Studies on the topic, however, seem particularly relevant in view of the establishment of a single market for consumer credit. This article ultimately calls for further legal research to address consumer protection concerns and inform future legislation

    Allelic based gene-gene interactions in rheumatoid arthritis

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    The detection of gene-gene interaction is an important approach to understand the etiology of rheumatoid arthritis (RA). The goal of this study is to identify gene-gene interaction of SNPs at the allelic level contributing to RA using real data sets (Problem 1) of North American Rheumatoid Arthritis Consortium (NARAC) provided by Genetic Analysis Workshop 16 (GAW16). We applied our novel method that can detect the interaction by a definition of nonrandom association of alleles that occurs when the contribution to RA of a particular allele inherited in one gene depends on a particular allele inherited at other unlinked genes. Starting with 639 single-nucleotide polymorphisms (SNPs) from 26 candidate genes, we identified ten two-way interacting genes and one case of three-way interacting genes. SNP rs2476601 on PTPN22 interacts with rs2306772 on SLC22A4, which interacts with rs881372 on TRAF1 and rs2900180 on C5, respectively. SNP rs2900180 on C5 interacts with rs2242720 on RUNX1, which interacts with rs881375 on TRAF1. Furthermore, rs2476601 on PTPN22 also interacts with three SNPs (rs2905325, rs1476482, and rs2106549) in linkage disequilibrium (LD) on IL6. The other three SNPs (rs2961280, rs2961283, and rs2905308) in LD on IL6 interact with two SNPs (rs477515 and rs2516049) on HLA-DRB1. SNPs rs660895 and rs532098 on HLA-DRB1 interact with rs2834779 and four SNPs in LD on RUNX1. Three-way interacting genes of rs10229203 on IL6, rs4816502 on RUNX1, and rs10818500 on C5 were also detected

    Prediction of peptide and protein propensity for amyloid formation

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    Understanding which peptides and proteins have the potential to undergo amyloid formation and what driving forces are responsible for amyloid-like fiber formation and stabilization remains limited. This is mainly because proteins that can undergo structural changes, which lead to amyloid formation, are quite diverse and share no obvious sequence or structural homology, despite the structural similarity found in the fibrils. To address these issues, a novel approach based on recursive feature selection and feed-forward neural networks was undertaken to identify key features highly correlated with the self-assembly problem. This approach allowed the identification of seven physicochemical and biochemical properties of the amino acids highly associated with the self-assembly of peptides and proteins into amyloid-like fibrils (normalized frequency of β-sheet, normalized frequency of β-sheet from LG, weights for β-sheet at the window position of 1, isoelectric point, atom-based hydrophobic moment, helix termination parameter at position j+1 and ΔGº values for peptides extrapolated in 0 M urea). Moreover, these features enabled the development of a new predictor (available at http://cran.r-project.org/web/packages/appnn/index.html) capable of accurately and reliably predicting the amyloidogenic propensity from the polypeptide sequence alone with a prediction accuracy of 84.9 % against an external validation dataset of sequences with experimental in vitro, evidence of amyloid formation

    Evidence of Wave-Particle Duality for Single Fast Hydrogen Atoms

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    We report the direct observation of interference effects in a Young\u27s double-slit experiment where the interfering waves are two spatially separated components of the de Broglie wave of single 1.3 MeV hydrogen atoms formed close to either target nucleus in H++H2 electron-transfer collisions. Quantum interference strongly influences the results even though the hydrogen atoms have a de Broglie wavelength, λdB, as small as 25 fm

    A Novel Metagenomic Short-Chain Dehydrogenase/Reductase Attenuates Pseudomonas aeruginosa Biofilm Formation and Virulence on Caenorhabditis elegans

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    In Pseudomonas aeruginosa, the expression of a number of virulence factors, as well as biofilm formation, are controlled by quorum sensing (QS). N-Acylhomoserine lactones (AHLs) are an important class of signaling molecules involved in bacterial QS and in many pathogenic bacteria infection and host colonization are AHL-dependent. The AHL signaling molecules are subject to inactivation mainly by hydrolases (Enzyme Commission class number EC 3) (i.e. N-acyl-homoserine lactonases and N-acyl-homoserine-lactone acylases). Only little is known on quorum quenching mechanisms of oxidoreductases (EC 1). Here we report on the identification and structural characterization of the first NADP-dependent short-chain dehydrogenase/reductase (SDR) involved in inactivation of N-(3-oxo-dodecanoyl)-L-homoserine lactone (3-oxo-C12-HSL) and derived from a metagenome library. The corresponding gene was isolated from a soil metagenome and designated bpiB09. Heterologous expression and crystallographic studies established BpiB09 as an NADP-dependent reductase. Although AHLs are probably not the native substrate of this metagenome-derived enzyme, its expression in P. aeruginosa PAO1 resulted in significantly reduced pyocyanin production, decreased motility, poor biofilm formation and absent paralysis of Caenorhabditis elegans. Furthermore, a genome-wide transcriptome study suggested that the level of lasI and rhlI transcription together with 36 well known QS regulated genes was significantly (≥10-fold) affected in P. aeruginosa strains expressing the bpiB09 gene in pBBR1MCS-5. Thus AHL oxidoreductases could be considered as potent tools for the development of quorum quenching strategies
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