4,306 research outputs found

    Linearized gravity as a gauge theory

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    We discuss linearized gravity from the point of view of a gauge theory. In (3+1)-dimensions our analysis allows to consider linearized gravity in the context of the MacDowell-Mansouri formalism. Our observations may be of particular interest in the strong-weak coupling duality for linearized gravity, in Randall-Sundrum brane world scenario and in Ashtekar formalism.Comment: Latex, 13 page

    Hamiltonian Noether theorem for gauge systems and two time physics

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    The Noether theorem for Hamiltonian constrained systems is revisited. In particular, our review presents a novel method to show that the gauge transformations are generated by the conserved quantities associated with the first class constraints. We apply our results to the relativistic point particle, to the Friedberg et al. model and, with special emphasis, to two time physics.Comment: 20 pages, Latex, references added, the "massless" sense of (87) is clarifie

    Superfield Description of a Self-Dual Supergravity a la MacDowell-Mansouri

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    Using MacDowell-Mansouri theory, in this work, we investigate a superfield description of the self-dual supergravity a la Ashtekar. We find that in order to reproduce previous results on supersymmetric Ashtekar formalism, it is necessary to properly combine the supersymmetric field-strength in the Lagrangian. We extend our procedure to the case of supersymmetric Ashtekar formalism in eight dimensions.Comment: 19 pages, Latex; section 6 improve

    Hidden dual mathematical symmetry in the genetic code

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    We describe the genetic code in terms of numbers that help us to find several dual symmetries. Our formulation can even be rewritten regarding the up-down and right-left dual concepts. We argue that our work may bring many topological tools to studying the DNA molecule, including the Grassmann-PlĂŒcker coordinates, which are important in mathematical and physical contexts

    Exact, E=0, Solutions for General Power-Law Potentials. I. Classical Orbits

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    For zero energy, E=0E=0, we derive exact, classical solutions for {\em all} power-law potentials, V(r)=−γ/rÎœV(r)=-\gamma/r^\nu, with Îł>0\gamma>0 and −∞<Îœ<∞-\infty <\nu<\infty. When the angular momentum is non-zero, these solutions lead to the orbits (˚t)=[cosâĄÎŒ(th⁥(t)−th⁥0(t))]1/ÎŒ\r(t)= [\cos \mu (\th(t)-\th_0(t))]^{1/\mu}, for all ÎŒâ‰ĄÎœ/2−1≠0\mu \equiv \nu/2-1 \ne 0. When Îœ>2\nu>2, the orbits are bound and go through the origin. This leads to discrete discontinuities in the functional dependence of th⁥(t)\th(t) and th⁥0(t)\th_0(t), as functions of tt, as the orbits pass through the origin. We describe a procedure to connect different analytic solutions for successive orbits at the origin. We calculate the periods and precessions of these bound orbits, and graph a number of specific examples. Also, we explain why they all must violate the virial theorem. The unbound orbits are also discussed in detail. This includes the unusual orbits which have finite travel times to infinity and also the special Îœ=2\nu = 2 case.Comment: LaTeX, 27 pages with 12 figures available from the authors or can be generated from Mathematica instructions at end of the fil

    Sulfide-, fluorite-, barite-bearing siliceous "crusts" related to unconformity surfaces of different ages in Pyrenees and Alps: a new model in carbonate-hosted deposits?

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    Wumerous stratabound sulfide-, barite-, fluonte-bearing siliceous crusts, from dm to some tens of in thick, occur over large areas of the Alpine belt, ;.e. the Alps and the Pyrenees. They are linked to unconformlty landscapes evolved on various carbonate units of Paieozoic and Triassic sedimentq sequences. Since the study mineralizations constitute the transition between the underlying carbonates and the overlying detrital units, they can be considered as an independent lithostratigraphic units that record a particular metalogenetic process not only in the alpine chains but worldwide. These mineralizations exhibit several morphologies: tabular concordant with the unconfonnities bodies, columnar bodies, karstic cavity-fillings, laminites and veins. In addition, the study deposits are clearly affected by remobilization process occuned during diagenesis or metamorphism. Such processes are responsible for masking the occunence of the breccia/conglomerate typically located at the base of the orebodies.Although the study mineralizations have usually been included in MVT deposit class, constrastirig differences between their diagnostic features and those of MVT mineralizations, suggest that the inclusion of the mineralized crust deposits in the MVT group seem incorrect.These peculiar ore-bearing quartz-crusts, persistent over large areas and showing an independent and distinct character and constituting an important marker for some sedimentary sequences of different ages in Alpine belts, allow the authors to define a new metallogenic model named as "crust-type" (CT) deposits. Comparable mineralization in other geotectonic environments outside Alpine belts point out to CT deposits being a worldwide significant metallogenic event

    The Surface Brightness Fluctuations and Globular Cluster Populations of M87 and its Companions

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    Using the surface brightness fluctuations in HST WFPC-2 images, we determine that M87, NGC 4486B, and NGC 4478 are all at a distance of ~16 Mpc, while NGC 4476 lies in the background at ~21 Mpc. We also examine the globular clusters of M87 using archived HST fields. We detect the bimodal color distribution, and find that the amplitude of the red peak relative to the blue peak is greatest near the center. This feature is in good agreement with the merger model of elliptical galaxy formation, where some of the clusters originated in progenitor galaxies while other formed during mergers.Comment: 5 pages, 2 figure

    Self-dual gravity and self-dual Yang-Mills in the context of Macdowell-Mansouri formalism

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    In this work we propose an action which unifies self-dual gravity and self-dual Yang-Mills in the context of the Macdowell-Mansouri formalism. We claim that such an action may be used to find the S-dual action for both self-dual gravity and self-dual Yang-Mills.Comment: 8 pages, Revtex, no figures, submitted to Phys. Rev.

    Self-Dual Conformal Supergravity and the Hamiltonian Formulation

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    In terms of Dirac matrices the self-dual and anti-self-dual decomposition of a conformal supergravity is given and a self-dual conformal supergravity theory is developed as a connection dynamic theory in which the basic dynamic variabes include the self-dual spin connection i.e. the Ashtekar connection rather than the triad. The Hamiltonian formulation and the constraints are obtained by using the Dirac-Bergmann algorithm. PACS numbers: 04.20.Cv, 04.20.Fy,04.65.+

    Performance of Slow-Growing Chickens Fed with Tenebrio molitor Larval Meal as a Full Replacement for Soybean Meal

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    Insect larval meal is an increasingly common protein source in poultry systems. In this study, the effect of replacing soybean meal with Tenebrio molitor larval meal on the performance of slow-growing chickens was assessed. A total of 128 one-day-old chickens (Colorield) were randomly divided into a control group (C) (n = 64), fed with soybean meal, and an experimental group (TM) (n = 64), fed with T. molitor larvae meal. The chicks were slaughtered after 95 days. Three different isoenergetic and isoproteic diets (F1, F2 and F3) were used for each group. The F1 diet resulted in higher body weight gain and higher feed and water intakes in group C, but a lower feed conversion ratio. Contrarily, diets F2 and F3 did not produce differences in the studied parameters between the two groups, except for body weight gain in the case of diet F2, which was highest in group C. Therefore, weight gain and feed and water intakes were significantly higher in group C, but there were no differences in feed conversion ratio or live weight. In conclusion, the total replacement of soybean meal with T. molitor larvae meal resulted in a reduction in feed intake and a consequent reduction in weight. During this period, partial rather than total substitution may be recommended. © 2022 by the authors. Licensee MDPI, Basel, Switzerland
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