757 research outputs found

    Equivariant Poincar\'e series of filtrations and topology

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    Earlier, for an action of a finite group GG on a germ of an analytic variety, an equivariant GG-Poincar\'e series of a multi-index filtration in the ring of germs of functions on the variety was defined as an element of the Grothendieck ring of GG-sets with an additional structure. We discuss to which extend the GG-Poincar\'e series of a filtration defined by a set of curve or divisorial valuations on the ring of germs of analytic functions in two variables determines the (equivariant) topology of the curve or of the set of divisors

    Fruit quality of Chenin Blanc grape influenced by different rootstocks during a production cycle in the second half.

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    This study aimed to evaluate the influence of different rootstocks on physico-chemical characteristics of the fruits of Chenin Blanc grapes produced in the second half of the year

    An algebraic proof of Bogomolov-Tian-Todorov theorem

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    We give a completely algebraic proof of the Bogomolov-Tian-Todorov theorem. More precisely, we shall prove that if X is a smooth projective variety with trivial canonical bundle defined over an algebraically closed field of characteristic 0, then the L-infinity algebra governing infinitesimal deformations of X is quasi-isomorphic to an abelian differential graded Lie algebra.Comment: 20 pages, amspro

    Lambda polarization and single-spin left-right asymmetry in diffractive hadron-hadron collisions

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    We discuss Lambda polarization and single-spin left-right asymmetry in diffractive hadron-hadron scattering at high energies. We show that the physical picture proposed in a recent Letter is consistent with the experimental observation that Λ\Lambda polarization in the diffractive process, ppΛK+ppp\to \Lambda K^+p, is much higher than that in the inclusive reaction, ppΛXpp\to \Lambda X. We make predictions for the left-right asymmetry, A_N, and for the spin transfer, DNNΛD_{NN}^\Lambda, in the single-spin process p()pΛK+pp(\uparrow)p\to \Lambda K^+p and suggest further experimental tests of the proposed picture.Comment: 14 pages, 3 ps-figures. Phys. Rev. D (in press

    A Chromo-Fluorogenic Synthetic Canary for CO Detection Based on a Pyrenylvinyl Ruthenium(II) Complex

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    The chromo-fluorogenic detection of carbon monoxide in air has been achieved using a simple, inexpensive system based on ruthenium(II). This probe shows exceptional sensitivity and selectivity in its sensing behavior in the solid state. A color response visible to the naked eye is observed at 5 ppb of CO, and a remarkably clear color change occurs from orange to yellow at the onset of toxic CO concentrations (100 ppm) in air. Even greater sensitivity (1 ppb) can be achieved through a substantial increase in turn-on emission fluorescence in the presence of carbon monoxide, both in air and in solution. No response is observed with other gases including water vapor. Immobilization of the probe on a cellulose strip allows the system to be applied in its current form in a simple optoelectronic device to give a numerical reading and/or alarm.Financial support from the Spanish Government (project MAT2012-38429-C04) and the Generalitat Valenciana (project PROMETEO/2009/016) is gratefully acknowledged. M.E.M. is grateful to the Spanish Ministerio de Ciencia e Innovacion for an FPU grant. J.D.E.T.W.-E. and A.T. acknowledge the Leverhulme Trust for a grant (RPG-2012-634).Moragues Pons, ME.; Toscani, A.; Sancenón Galarza, F.; Martínez-Máñez, R.; White, A.; Wilton-Ely, JDET. (2014). A Chromo-Fluorogenic Synthetic Canary for CO Detection Based on a Pyrenylvinyl Ruthenium(II) Complex. Journal of the American Chemical Society. 136(34):11930-11933. https://doi.org/10.1021/ja507014aS11930119331363

    Polarization of Lambda^0 hyperons in nucleus-nucleus collisions at high energies

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    The measurement of Lambda^0 hyperons polarization in nucleus-nucleus collisions is considered as one of possible tools to study the phase transition. Fixed target and collider experiments are discussed for the case of Lambda^0's production from Au-Au central collisions at \sqrt{s_{NN}} of several GeV.Comment: 15 pages, 6 figure

    Magnetism of small V clusters embedded in a Cu fcc matrix: an ab initio study

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    We present extensive first principles density functional theory (DFT) calculations dedicated to analyze the magnetic and electronic properties of small Vn_{n} clusters (n=1,2,3,4,5,6) embedded in a Cu fcc matrix. We consider different cluster structures such as: i) a single V impurity, ii) several V2_{2} dimers having different interatomic distance and varying local atomic environment, iii) V3_{3} and iv) V4_{4} clusters for which we assume compact as well as 2- and 1-dimensional atomic configurations and finally, in the case of the v) V5_{5} and vi) V6_{6} structures we consider a square pyramid and a square bipyramid together with linear arrays, respectively. In all cases, the V atoms are embedded as substitutional impurities in the Cu network. In general, and as in the free standing case, we have found that the V clusters tend to form compact atomic arrays within the cooper matrix. Our calculated non spin-polarized density of states at the V sites shows a complex peaked structure around the Fermi level that strongly changes as a function of both the interatomic distance and local atomic environment, a result that anticipates a non trivial magnetic behavior. In fact, our DFT calculations reveal, in each one of our clusters systems, the existence of different magnetic solutions (ferromagnetic, ferrimagnetic, and antiferromagnetic) with very small energy differences among them, a result that could lead to the existence of complex finite-temperature magnetic properties. Finally, we compare our results with recent experimental measurements.Comment: 7 pages and 4 figure
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