1,280 research outputs found
Conformal anomaly from gauge fields without gauge fixing
We show how the Weyl anomaly generated by gauge fields, can be computed from
manifestly gauge invariant and diffeomorphism invariant exact renormalization
group equations, without having to fix the gauge at any stage. Regularisation
is provided by covariant higher derivatives and by embedding the Maxwell field
into a spontaneously broken supergauge theory. We first provide a
realisation that leaves behind two versions of the original gauge field,
and then construct a manifestly supergauge invariant flow equation
which leaves behind only the original Maxwell field in the spontaneously broken
regime.Comment: 24 page
Scheme Independence to all Loops
The immense freedom in the construction of Exact Renormalization Groups means
that the many non-universal details of the formalism need never be exactly
specified, instead satisfying only general constraints. In the context of a
manifestly gauge invariant Exact Renormalization Group for SU(N) Yang-Mills, we
outline a proof that, to all orders in perturbation theory, all explicit
dependence of beta function coefficients on both the seed action and details of
the covariantization cancels out. Further, we speculate that, within the
infinite number of renormalization schemes implicit within our approach, the
perturbative beta function depends only on the universal details of the setup,
to all orders.Comment: 18 pages, 8 figures; Proceedings of Renormalization Group 2005,
Helsinki, Finland, 30th August - 3 September 2005. v2: Published in jphysa;
minor changes / refinements; refs. adde
N=1* model superpotential revisited (IR behaviour of N=4 limit)
The one-loop contribution to the superpotential, in particular the
Veneziano-Yankielowicz potential in N=1 supersymmetric Yang-Mills model is
discussed from an elementary field theory method and the matrix model point of
view. Both approaches are based on the Renormalization Group variation of the
superconformal N=4 supersymmetric Yang-Mills model.Comment: 31 page
Teaching the Universal Language of Creativity: A Guide to Training.
Teaching the Universal Language of Creativity: A Guide to Training.
The purpose of education in any regard is to provide knowledge and information, to teach something. Parents, educators, and professionals alike are experiencing some difficulty in education, in that they are not being properly taught how to nurture some particular needs of individuals with developmental disabilities, specifically on how to use creativity to do so. Educators, parents, and professionals in the field need to start advocating for a balance between strict regulations and creativity. In the recent years, there has been quite the push for creativity and innovation in businesses, nationally and internationally, so where is the same push for education? This project examines creativity, in a scholarly sense, since its beginning, as well as new standards placed in public school systems, specifically in Buffalo, NY, that seem to stifle creativity. Using interviews and short survey results, the project examines and presents a curriculum to incorporate creativity into educating those who interact with individuals with developmental disabilities on a regular basis.
Keywords: creativity, education, special education, developmental disabilities, Common Core, International Center for Studies in Creativity, curriculum
Sensitivity of Nonrenormalizable Trajectories to the Bare Scale
Working in scalar field theory, we consider RG trajectories which correspond
to nonrenormalizable theories, in the Wilsonian sense. An interesting question
to ask of such trajectories is, given some fixed starting point in parameter
space, how the effective action at the effective scale, Lambda, changes as the
bare scale (and hence the duration of the flow down to Lambda) is changed. When
the effective action satisfies Polchinski's version of the Exact
Renormalization Group equation, we prove, directly from the path integral, that
the dependence of the effective action on the bare scale, keeping the
interaction part of the bare action fixed, is given by an equation of the same
form as the Polchinski equation but with a kernel of the opposite sign. We then
investigate whether similar equations exist for various generalizations of the
Polchinski equation. Using nonperturbative, diagrammatic arguments we find that
an action can always be constructed which satisfies the Polchinski-like
equation under variation of the bare scale. For the family of flow equations in
which the field is renormalized, but the blocking functional is the simplest
allowed, this action is essentially identified with the effective action at
Lambda = 0. This does not seem to hold for more elaborate generalizations.Comment: v1: 23 pages, 5 figures, v2: intro extended, refs added, published in
jphy
Green Fluorescent Protein in the sea urchin: new experimental approaches to transcriptional regulatory analysis in embryos and larvae
The use of Green Fluorescent Protein (GFP) as a reporter
for expression transgenes opens the way to several new
experimental strategies for the study of gene regulation in
sea urchin development. A GFP coding sequence was associated
with three different previously studied cis-regulatory
systems, viz those of the SM50 gene, expressed in skeletogenic mesenchyme, the CyIIa gene, expressed in archenteron, skeletogenic and secondary mesenchyme, and the
Endo16 gene, expressed in vegetal plate, archenteron and
midgut. We demonstrate that the sensitivity with which
expression can be detected is equal to or greater than that
of whole-mount in situ hybridization applied to detection
of CAT mRNA synthesized under the control of the same
cis-regulatory systems. However, in addition to the
important feature that it can be visualized nondestructively
in living embryos, GFP has other advantages. First, it freely diffuses even within fine cytoplasmic cables, and thus reveals connections between cells, which in sea urchin
embryos is particularly useful for observations on regulatory systems that operate in the syncytial skeletogenic mesenchyme. Second, GFP expression can be dramatically visualized in postembryonic larval tissues. This brings postembryonic larval developmental processes for the first time within the easy range of gene transfer analyses. Third, GFP permits identification and segregation of embryos in which the clonal incorporation of injected DNA has occurred in any particular desired region of the embryo. Thus, we show explicitly that, as expected, GFP transgenes are incorporated in the same nuclei together with other transgenes with which they are co-injected
N=1* model and glueball superpotential from Renormalization-Group-improved perturbation theory
A method for computing the low-energy non-perturbative properties of SUSY
GFT, starting from the microscopic lagrangian model, is presented. The method
relies on covariant SUSY Feynman graph techniques, adapted to low energy, and
Renormalization-Group-improved perturbation theory. We apply the method to
calculate the glueball superpotential in N=1 SU(2) SYM and obtain a potential
of the Veneziano-Yankielowicz type.Comment: 19 pages, no figures; added references; note added at the end of the
paper; version to appear in JHE
Parameterisation of the chemical effects of sprites in the middle atmosphere
Transient luminous events, such as red sprites, occur in the middle atmosphere in the electric field above thunderstorms. We here address the question whether these processes may be a significant source of odd nitrogen and affect ozone or other important trace species. A well-established coupled ion-neutral chemical model has been extended for this purpose and applied together with estimated rates of ionisation, excitation and dissociation based on spectroscopic ratios from ISUAL on FORMOSAT-2. This approach is used to estimate the NO<sub>x</sub> and ozone changes for two type cases. <br><br> The NO<sub>x</sub> enhancements are at most one order of magnitude in the streamers, which means a production of at most 10 mol per event, or (given a global rate of occurrence of three events per minute) some 150&ndash;1500 kg per day. The present study therefore indicates that sprites are insignificant as a global source of NO<sub>x</sub>. Local effects on ozone are also negligible, but the local enhancement of NO<sub>x</sub> may be significant, up to 5 times the minimum background at 70 km in extraordinary cases
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