23,806 research outputs found

    North Atlantic Deep Water Formation

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    Various studies concerning differing aspects of the North Atlantic are presented. The three major topics under which the works are classified include: (1) oceanography; (2) paleoclimate; and (3) ocean, ice and climate modeling

    The Crystal and Molecular Structure of a Trifluoroacetylacetonate Complex of Scandium, Sc(CH\u3csub\u3e3\u3c/sub\u3eCOCHCOCF\u3csub\u3e3\u3c/sub\u3e)\u3csub\u3e3\u3c/sub\u3e

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    The crystal and molecular structure of Sc(CH3COCHCOCF3)3 has been determined by X-ray diffraction. The compound crystallizes as pure mer-isomer in the orthorhombic space group Pbca with lattice parameters a=15.166(8) Å, b=13.560(7) Å, c=19.327(10) Å, α=β=γ=90°, V=3974(4) Å3, Z=8. The complex at 100 K is partially disordered in the crystal structure in an approximate 5:1 ratio with 83% fluorine population at C-11 and 17% at C-15. NMR data is compared to that previously reported

    Hadronic light-by-light scattering contribution to the muon anomalous magnetic moment revisited

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    We discuss hadronic light-by-light scattering contribution to the muon anomalous magnetic moment a_\mu^{\rm lbl}, paying particular attention to the consistent matching between the short- and the long-distance behavior of the light-by-light scattering amplitude. We argue that the short-distance QCD imposes strong constraints on this amplitude overlooked in previous analyses. We find that accounting for these constraints leads to approximately 50 per cent increase in the central value of a_\mu^{\rm lbl}, compared to existing estimates. The hadronic light-by-light scattering contribution becomes a_\mu^{\rm lbl}=136(25) \times 10^{-11}, thereby shifting the Standard Model prediction closer to the experimental value.Comment: 16 pages, 2 figure

    Crystal and molecular structure of bis(8-phenylmenthyl) 2-(2-methyl-5-oxo-3-cyclohexen-1-yl)propandioate, C\u3csub\u3e42\u3c/sub\u3eH\u3csub\u3e54\u3c/sub\u3eO\u3csub\u3e5\u3c/sub\u3e• CH\u3csub\u3e3\u3c/sub\u3eCN

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    The X-ray crystal structure of the title compound, as crystallized from acetonitrile-water was determined. The relative stereochemistry of the cyclohexenone ring with respect to the 8-phenylmenthyl esters was determined. The title compound crystallizes in the noncentrosymmetric space group P21, with a=8.9850(10) Å, b=15.575(3) Å, c=14.478(2) Å, β=94.61(2)°, and D calc=1.118 g cm−3 for Z=2

    Society of Lloyd's v Price: Characterization and 'gap' in the Conflict of Laws

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    For connoisseurs of legal arcana, the case of Society of Lloyd's v Price; Society of Lloyd's v Lee 2006 (5) SA 393 (SCA) (hereafter Society of Lloyd's) has a special significance. Not only did it settle the question how best to characterize causes of action, but it also offered a solution for that curious problem of 'gap'. Both of these are issues arising out of conflicts of law. In itself the conflict of laws is an abstruse discipline, for it involves not simply the application of law to facts, but rather the application of a set of second-order choice-of-law rules which are designed to indicate what law should be applied to facts that happen to contain a foreign element. The Society of Lloyd’s case, however, took matters a stage further: the logic of the choice-of-law process drove the court to a point where it discovered that, in the circumstances of the case, no law was applicable. In conflict jargon, this conundrum is known as a problem of ‘gap’. (Its counterpart is ‘cumulation’, namely the simultaneous applicability of two or more laws.

    Factoring in a Dissipative Quantum Computer

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    We describe an array of quantum gates implementing Shor's algorithm for prime factorization in a quantum computer. The array includes a circuit for modular exponentiation with several subcomponents (such as controlled multipliers, adders, etc) which are described in terms of elementary Toffoli gates. We present a simple analysis of the impact of losses and decoherence on the performance of this quantum factoring circuit. For that purpose, we simulate a quantum computer which is running the program to factor N = 15 while interacting with a dissipative environment. As a consequence of this interaction randomly selected qubits may spontaneously decay. Using the results of our numerical simulations we analyze the efficiency of some simple error correction techniques.Comment: plain tex, 18 pages, 8 postscript figure

    Preparation, Characterization and Reactivity of (3-Methylpentadienyl)iron(1+) Cations

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    The title cations (9 and 12) were prepared by dehydration of (3-methyl-2,4-pentadien-1-ol)Fe(CO)2L+ complexes. The structure of the (CO)2PPh3-ligated 12 was determined by single-crystal X-ray analysis. Reaction of carbon and heteroatom nucleophiles to (3-methylpentadienyl)Fe(CO)3+ cations 9 and 12 proceeds either via attack at the dienyl terminus to give (3-methyl-1,3Z-diene)iron complexes or via attack at the internal carbon, followed by carbon monoxide insertion and reductive elimination to afford 3-methyl-4-substituted cyclohexenones. Cyclohexenone formation was found to be prevalent for addition of stabilized nucleophiles with strongly dissociated counterions to cation 9 (L = CO). Reaction of cation 9 with sodium bis[(−)-8-phenylmenthyl] malonate gave a single diastereomeric cyclohexenone

    The Ingwavuma Land Deal: A Case Study of Self-Determination

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    Analysis of surface tris (2,3-dibromopropyl) phosphate on chlorobutyl rubber SCAPE suits

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    Tris (2,30-dibromopropyl) phosphate was used to confer flame retardant properties on butyl rubber formulations used in protective clothing such as the self-contained atmospheric protective ensembles (SCAPE suits) worn at Kennedy Space Center in support of Apollo, Skylab, and Apollo-Soyuz missions since 1966. Because tris (2,3-dibromopropyl) phosphate is mutagenic, surface concentrations of the compound in SCAPE suits were investigated as were as potential methods of removing or isolating it. Analytical procedures for determining surface concentrations of the tris compound on non-porous materials are described. Soap-and-water washing is the most efficient method of removing the compound from fabricated SCAPE suits and unused material
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