8,633 research outputs found

    Merging fragments of classical logic

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    We investigate the possibility of extending the non-functionally complete logic of a collection of Boolean connectives by the addition of further Boolean connectives that make the resulting set of connectives functionally complete. More precisely, we will be interested in checking whether an axiomatization for Classical Propositional Logic may be produced by merging Hilbert-style calculi for two disjoint incomplete fragments of it. We will prove that the answer to that problem is a negative one, unless one of the components includes only top-like connectives.Comment: submitted to FroCoS 201

    Lymphocyte apoptosis, macrophage function and disease activity in systemic lupus erythematosus

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    Deacidification of palm oil using solvent extraction integrated with membrane technology

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    In this work, the efficiency of crude palm oil (CPO) deacidification using solvent extraction integrated with membrane technology is studied. Different solvents including ethanol, hexane and methanol were selected to extract the palmitic acid from model fatty system in the model fatty system to solvent ratio of 1:2. Experimental results showed that ethanol was the best solvent to extract palmitic acid from the model fatty system, recording about 65.5% fatty acid reduction in the model fatty system. Three commercial solvent resistant nanofiltration (SRNF) membranes (SolSep NF010206, NF030306, and NF030705) were then selected to examine their respective performance in recovering ethanol from palmitic acid-rich ethanol solvent. The results revealed that the combination of solvent extraction and membrane technology is remarkable simple and waste-free approach to overcome major drawbacks of conventional refinery operation

    Improved outer boundary conditions for Einstein's field equations

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    In a recent article, we constructed a hierarchy B_L of outer boundary conditions for Einstein's field equations with the property that, for a spherical outer boundary, it is perfectly absorbing for linearized gravitational radiation up to a given angular momentum number L. In this article, we generalize B_2 so that it can be applied to fairly general foliations of spacetime by space-like hypersurfaces and general outer boundary shapes and further, we improve B_2 in two steps: (i) we give a local boundary condition C_2 which is perfectly absorbing including first order contributions in 2M/R of curvature corrections for quadrupolar waves (where M is the mass of the spacetime and R is a typical radius of the outer boundary) and which significantly reduces spurious reflections due to backscatter, and (ii) we give a non-local boundary condition D_2 which is exact when first order corrections in 2M/R for both curvature and backscatter are considered, for quadrupolar radiation.Comment: accepted Class. Quant. Grav. numerical relativity special issue; 17 pages and 1 figur

    Low Energy States of 3181Ga50^{81}_{31} Ga_{50} : Elements on the Doubly-Magic Nature of 78^{78}Ni

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    Excited levels were attributed to 3181^{81}_{31}Ga50_{50} for the first time which were fed in the β\beta-decay of its mother nucleus 81^{81}Zn produced in the fission of nat^{nat}U using the ISOL technique. We show that the structure of this nucleus is consistent with that of the less exotic proton-deficient N=50 isotones within the assumption of strong proton Z=28 and neutron N=50 effective shell effects.Comment: 4 pages, REVTeX 4, 5 figures (eps format

    Motivating compliance: Juvenile probation officer strategies and skills

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    Juvenile probation officers aim to improve youth compliance with probation conditions, but questions remain about how officers motivate youth. The study’s purpose was to determine which officer-reported probation strategies (client-centered vs. confrontational) were associated with their use of evidence-based motivational interviewing skills. Officers (N = 221) from 18 Indiana counties demonstrated motivational interviewing skills by responding to scenarios depicting issues common to youth probationers. Results of a hierarchical multiple regression analysis indicated that, while officer endorsement of client-centered strategies was not associated with differential use of motivational interviewing skills, officers endorsing confrontational strategies were less likely to demonstrate motivational interviewing skills

    Geometrical Magnetic Frustration in Rare Earth Chalcogenide Spinels

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    We have characterized the magnetic and structural properties of the CdLn2Se4 (Ln = Dy, Ho), and CdLn2S4 (Ln = Ho, Er, Tm, Yb) spinels. We observe all compounds to be normal spinels, possessing a geometrically frustrated sublattice of lanthanide atoms with no observable structural disorder. Fits to the high temperature magnetic susceptibilities indicate these materials to have effective antiferromagnetic interactions, with Curie-Weiss temperatures theta ~ -10 K, except CdYb2S4 for which theta ~ -40 K. The absence of magnetic long range order or glassiness above T = 1.8 K strongly suggests that these materials are a new venue in which to study the effects of strong geometrical frustration, potentially as rich in new physical phenomena as that of the pyrochlore oxides.Comment: 17 pages, 5 figures, submitted to Phys Rev B; added acknowledgement

    Testing outer boundary treatments for the Einstein equations

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    Various methods of treating outer boundaries in numerical relativity are compared using a simple test problem: a Schwarzschild black hole with an outgoing gravitational wave perturbation. Numerical solutions computed using different boundary treatments are compared to a `reference' numerical solution obtained by placing the outer boundary at a very large radius. For each boundary treatment, the full solutions including constraint violations and extracted gravitational waves are compared to those of the reference solution, thereby assessing the reflections caused by the artificial boundary. These tests use a first-order generalized harmonic formulation of the Einstein equations. Constraint-preserving boundary conditions for this system are reviewed, and an improved boundary condition on the gauge degrees of freedom is presented. Alternate boundary conditions evaluated here include freezing the incoming characteristic fields, Sommerfeld boundary conditions, and the constraint-preserving boundary conditions of Kreiss and Winicour. Rather different approaches to boundary treatments, such as sponge layers and spatial compactification, are also tested. Overall the best treatment found here combines boundary conditions that preserve the constraints, freeze the Newman-Penrose scalar Psi_0, and control gauge reflections.Comment: Modified to agree with version accepted for publication in Class. Quantum Gra

    Implication of the overlap representation for modelling generalized parton distributions

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    Based on a field theoretically inspired model of light-cone wave functions, we derive valence-like generalized parton distributions and their double distributions from the wave function overlap in the parton number conserved s-channel. The parton number changing contributions in the t-channel are restored from duality. In our construction constraints of positivity and polynomiality are simultaneously satisfied and it also implies a model dependent relation between generalized parton distributions and transverse momentum dependent parton distribution functions. The model predicts that the t-behavior of resulting hadronic amplitudes depends on the Bjorken variable x_Bj. We also propose an improved ansatz for double distributions that embeds this property.Comment: 15 pages, 8 eps figure

    General metabolism of Laribacter hongkongensis: a genome-wide analysis

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    <p>Abstract</p> <p>Background</p> <p><it>Laribacter hongkongensis </it>is associated with community-acquired gastroenteritis and traveler's diarrhea. In this study, we performed an in-depth annotation of the genes and pathways of the general metabolism of <it>L. hongkongensis </it>and correlated them with its phenotypic characteristics.</p> <p>Results</p> <p>The <it>L. hongkongensis </it>genome possesses the pentose phosphate and gluconeogenesis pathways and tricarboxylic acid and glyoxylate cycles, but incomplete Embden-Meyerhof-Parnas and Entner-Doudoroff pathways, in agreement with its asaccharolytic phenotype. It contains enzymes for biosynthesis and β-oxidation of saturated fatty acids, biosynthesis of all 20 universal amino acids and selenocysteine, the latter not observed in <it>Neisseria gonorrhoeae</it>, <it>Neisseria meningitidis </it>and <it>Chromobacterium violaceum</it>. The genome contains a variety of dehydrogenases, enabling it to utilize different substrates as electron donors. It encodes three terminal cytochrome oxidases for respiration using oxygen as the electron acceptor under aerobic and microaerophilic conditions and four reductases for respiration with alternative electron acceptors under anaerobic conditions. The presence of complete tetrathionate reductase operon may confer survival advantage in mammalian host in association with diarrhea. The genome contains CDSs for incorporating sulfur and nitrogen by sulfate assimilation, ammonia assimilation and nitrate reduction. The existence of both glutamate dehydrogenase and glutamine synthetase/glutamate synthase pathways suggests an importance of ammonia metabolism in the living environments that it may encounter.</p> <p>Conclusions</p> <p>The <it>L. hongkongensis </it>genome possesses a variety of genes and pathways for carbohydrate, amino acid and lipid metabolism, respiratory chain and sulfur and nitrogen metabolism. These allow the bacterium to utilize various substrates for energy production and survive in different environmental niches.</p
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