3,183 research outputs found

    Summing Radiative Corrections to the Effective Potential

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    When one uses the Coleman-Weinberg renormalization condition, the effective potential VV in the massless ϕ44\phi_4^4 theory with O(N) symmetry is completely determined by the renormalization group functions. It has been shown how the (p+1)(p+1) order renormalization group function determine the sum of all the N^{\mbox{\scriptsize p}}LL order contribution to VV to all orders in the loop expansion. We discuss here how, in addition to fixing the N^{\mbox{\scriptsize p}}LL contribution to VV, the (p+1)(p+1) order renormalization group functions also can be used to determine portions of the N^{\mbox{\scriptsize p+n}}LL contributions to VV. When these contributions are summed to all orders, the singularity structure of \mcv is altered. An alternate rearrangement of the contributions to VV in powers of lnϕ\ln \phi, when the extremum condition V(ϕ=v)=0V^\prime (\phi = v) = 0 is combined with the renormalization group equation, show that either v=0v = 0 or VV is independent of ϕ\phi. This conclusion is supported by showing the LL, \cdots, N4^4LL contributions to VV become progressively less dependent on ϕ\phi.Comment: 16 pages; added 2 figures and 2 tables; references revise

    Evaluación genética en etapa de vivero de áreas productoras de semillas (APS) de Pino Ponderosa en Nordpatagonia

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    El Pino Ponderosa (Pinus ponderosa Dougl. ex Laws) es la principal especie forestal implantada en secanoen la Patagonia. Su potencialidad productiva y la disponibilidad de tierras para su cultivo permiten proyectarla continuidad de su uso en plantaciones comerciales, para lo que es indispensable asegurar la provisión desemillas de adecuada calidad genética. Las semillas utilizadas en la última década se produjeron en una seriede rodales mediante ensayos para evaluar su descendencia. El objetivo del presente trabajo es evaluar estosrodales ensayando su descendencia. En este primer reporte presentamos los resultados de una evaluaciónen etapa de vivero. Se ensayaron 31 procedencias locales seleccionadas (Áreas Productoras de Semillas,APS) en dos sitios, midiendo altura y diámetro a la altura del cuello en plantines de 2 años de edad. A través de análisis de la varianza se probó un claro efecto de interacción entre las APS y los sitios, y también diferencias entre las APS dentro de cada sitio. Seguidamente, se establecieron rankings de las APS por sitio y variable evaluada. A través de comparaciones de a pares se formaron grupos homogéneos. También se estimó la estabilidad genotípica de las APS por medio del cálculo de sus ecovalencias. Los resultados son aún preliminares, pero el haber probado diferencias en tan temprana edad nos alerta sobre la importancia de la procedencia de las semillas a utilizar para la producción comercial. Se espera que estas diferencias se acentúen en edades más avanzadas. Para probarlo, ya se han establecido ensayos de plantación

    On Gauge Equivalence of Tachyon Solutions in Cubic Neveu-Schwarz String Field Theory

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    Simple analytic solution to cubic Neveu-Schwarz String Field Theory including the GSO()GSO(-) sector is presented. This solution is an analog of the Erler-Schnabl solution for bosonic case and one of the authors solution for the pure GSO(+)GSO(+) case. Gauge transformations of the new solution to others known solutions for the NSNS string tachyon condensation are constructed explicitly. This gauge equivalence manifestly supports the early observed fact that these solutions have the same value of the action density.Comment: 8 pages, LaTe

    An Alternative Method to Niskin Sampling for Molecular Analysis of the Marine Environment

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    The development of low-cost, open-source Remotely Operated Vehicle (ROV) systems has provided almost unrestricted access for researchers looking to monitor the marine environment in ever greater resolution. Sampling microbial communities from the marine environment, however, still usually relies on Niskin-bottle sampling (ROV or Conductivity-Temperature-Depth sampler (CTD) based), a method which introduces an inaccuracy and variability that is incompatible with metatranscriptomic analysis, for example. Here, we describe a versatile, easily-replicated platform which achieves in situ mRNA preservation, via the addition of RNAlater to filtered microbial cells, to enhance ROV or CTD functionality

    New Loop Representations for 2+1 Gravity

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    Since the gauge group underlying 2+1-dimensional general relativity is non-compact, certain difficulties arise in the passage from the connection to the loop representations. It is shown that these problems can be handled by appropriately choosing the measure that features in the definition of the loop transform. Thus, ``old-fashioned'' loop representations - based on ordinary loops - do exist. In the case when the spatial topology is that of a two-torus, these can be constructed explicitly; {\it all} quantum states can be represented as functions of (homotopy classes of) loops and the scalar product and the action of the basic observables can be given directly in terms of loops.Comment: 28pp, 1 figure (postscript, compressed and uuencoded), TeX, Pennsylvania State University, CGPG-94/5-

    QSD IV : 2+1 Euclidean Quantum Gravity as a model to test 3+1 Lorentzian Quantum Gravity

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    The quantization of Lorentzian or Euclidean 2+1 gravity by canonical methods is a well-studied problem. However, the constraints of 2+1 gravity are those of a topological field theory and therefore resemble very little those of the corresponding Lorentzian 3+1 constraints. In this paper we canonically quantize Euclidean 2+1 gravity for arbitrary genus of the spacelike hypersurface with new, classically equivalent constraints that maximally probe the Lorentzian 3+1 situation. We choose the signature to be Euclidean because this implies that the gauge group is, as in the 3+1 case, SU(2) rather than SU(1,1). We employ, and carry out to full completion, the new quantization method introduced in preceding papers of this series which resulted in a finite 3+1 Lorentzian quantum field theory for gravity. The space of solutions to all constraints turns out to be much larger than the one as obtained by traditional approaches, however, it is fully included. Thus, by suitable restriction of the solution space, we can recover all former results which gives confidence in the new quantization methods. The meaning of the remaining "spurious solutions" is discussed.Comment: 35p, LATE
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