Mass generation for non-Abelian antisymmetric tensor fields in a three-dimensional space-time

Starting from a recently proposed Abelian topological model in (2+1) dimensions, which involve the Kalb-Ramond two form field, we study a non-Abelian generalization of the model. An obstruction for generalization is detected. However we show that the goal is achieved if we introduce a vectorial auxiliary field. Consequently, a model is proposed, exhibiting a non-Abelian topological mass generation mechanism in D=3, that provides mass for the Kalb-Ramond field. The covariant quantization of this model requires ghosts for ghosts. Therefore in order to quantize the theory we construct a complete set of BRST and anti-BRST equations using the horizontality condition.Comment: 8 pages. To appear in Physical Review

Wavelets: a powerful tool for studying rotation, activity, and pulsation in Kepler and CoRoT stellar light curves

Aims. The wavelet transform has been used as a powerful tool for treating several problems in astrophysics. In this work, we show that the time-frequency analysis of stellar light curves using the wavelet transform is a practical tool for identifying rotation, magnetic activity, and pulsation signatures. We present the wavelet spectral composition and multiscale variations of the time series for four classes of stars: targets dominated by magnetic activity, stars with transiting planets, those with binary transits, and pulsating stars. Methods. We applied the Morlet wavelet (6th order), which offers high time and frequency resolution. By applying the wavelet transform to the signal, we obtain the wavelet local and global power spectra. The first is interpreted as energy distribution of the signal in time-frequency space, and the second is obtained by time integration of the local map. Results. Since the wavelet transform is a useful mathematical tool for nonstationary signals, this technique applied to Kepler and CoRoT light curves allows us to clearly identify particular signatures for different phenomena. In particular, patterns were identified for the temporal evolution of the rotation period and other periodicity due to active regions affecting these light curves. In addition, a beat-pattern signature in the local wavelet map of pulsating stars over the entire time span was also detected.Comment: Accepted for publication on A&

Pesquisa com arroz de sequeiro no Estado do Acre.

Melhoramento: Introdução; Competição de cultivares de arroz de sequeiro. Rio Branco, 1976 e 1977/78; Introdução de cultivares de arroz de sequeiro. Rio Branco-Ac, 1977; Introdução e avaliação de cultivares de arroz. Rio Branco, 1979; Comportamento de cultivares e linhagens de arroz de sequeiro na microrregião Alto Purus-Acre. Rio Branco, 1978/79; Competição de cultivares internacionais de arroz. Rio Branco, 1978/79; Comportamento de cultivares de arroz irrigado sob regime de sequeiro favorecido. Rio Branco-Ac, 1980/81-1981/82; Avaliações preliminares de cultivares e linhagens de arroz de sequeiro. Rio Branco-Ac, 1982; Avaliações de genótipos de arroz de sequeiro em ensaios integrados. Rio Branco-Ac, 1980/81 - 1981/82; Publicações; Fitotecnia; Fitopatologia; Entomologia; Agradecimentos; Literatura consultada.bitstream/item/75595/1/CPAF-AC-DOC-3-84.pdfEditores: César Sabogal; José Natalino Macedo Silv

Aspects of U-duality in BLG models with Lorentzian metric 3-algebras

In our previous paper, it was shown that BLG model based on a Lorentzian metric 3-algebra gives Dp-brane action whose worldvolume is compactified on torus T^d (d=p-2). Here the 3-algebra was a generalized one with d+1 pairs of Lorentzian metric generators and expressed in terms of a loop algebra with central extensions. In this paper, we derive the precise relation between the coupling constant of the super Yang-Mills, the moduli of T^d and some R-R flux with VEV's of ghost fields associated with Lorentzian metric generators. In particular, for d=1, we derive the Yang-Mills action with theta term and show that SL(2,Z) Montonen-Olive duality is realized as the rotation of two VEV's. Furthermore, some moduli parameters such as NS-NS 2-form flux are identified as the deformation parameters of the 3-algebras. By combining them, we recover most of the moduli parameters which are required by U-duality symmetry.Comment: 27 pages, v2: minor correction

Electrochemical catalytic cyclization reactions using environmentally friendly methodologies

The electrochemical intramolecular cyclisation of bromoalkoxylated derivatives 1 was carried out using Ni(II) complexes as the catalysts in ethanol solutions by constant-current electrolysis in one-compartment cell in the absence of sacrificial anodes as an environmentally friendly system. The reduction of the substrates proceeds via one-electron cleavage of the carbon–bromine bond to form radical-type intermediates that undergo cyclisation to afford cyclic ethers in moderate to good yields.Fundação para a Ciência e a Tecnologia (FCT

The TARGET_TIA: A complete, flexible and sound territorial impact assessment tool

This chapter presents TARGET_TIA as a relevant and flexible Territorial Impact Assessment (TIA) methodology. TARGET_TIA was created in a context where existing ESPON TIA tools were mainly designed for assessing ex ante territorial impacts of EU directives. Hence, in view of the need to properly assess the main ex post territorial impacts of EU Cohesion Policy in several countries in a relevant and sound way, the author decided to design, test and apply his own TIA methodology, named TARGET_TIA. When compared with other existing TIA methodologies, TARGET_TIA can be used both at ex ante and ex post policy evaluation phases. In addition, it brings to the table the possibility to use counterfactual evaluation elements to allow the production of credible and sound TIA evaluation scores. Following on from its implementation in assessing the main territorial impacts of EU policies and programmes, mostly at the ex post evaluation phase, it is possible to conclude that it is a credible, flexible, easy-to-operate, cost-effective and robust TIA methodology, which can be applied to projects, programmes and policies, at all territorial levels.info:eu-repo/semantics/acceptedVersio

Abundant cyanopolyynes as a probe of infall in the Serpens South cluster-forming region

We have detected bright HC7N J = 21-20 emission toward multiple locations in the Serpens South cluster-forming region using the K-Band Focal Plane Array at the Robert C. Byrd Green Bank Telescope. HC7N is seen primarily toward cold filamentary structures that have yet to form stars, largely avoiding the dense gas associated with small protostellar groups and the main central cluster of Serpens South. Where detected, the HC7N abundances are similar to those found in other nearby star forming regions. Toward some HC7N `clumps', we find consistent variations in the line centroids relative to NH3 (1,1) emission, as well as systematic increases in the HC7N non-thermal line widths, which we argue reveal infall motions onto dense filaments within Serpens South with minimum mass accretion rates of M ~ 2-5 M_sun Myr^-1. The relative abundance of NH3 to HC7N suggests that the HC7N is tracing gas that has been at densities n ~ 10^4 cm^-3, for timescales t < 1-2 x 10^5 yr. Since HC7N emission peaks are rarely co-located with those of either NH3 or continuum, it is likely that Serpens South is not particularly remarkable in its abundance of HC7N, but instead the serendipitous mapping of HC7N simultaneously with NH3 has allowed us to detect HC7N at low abundances in regions where it otherwise may not have been looked for. This result extends the known star-forming regions containing significant HC7N emission from typically quiescent regions, like the Taurus molecular cloud, to more complex, active environments.Comment: 19 pages, 13 figures, accepted to MNRAS. Version with full resolution figures available at http://www.dunlap.utoronto.ca/~friesen/Friesen_HC7N.pd

Resultados dos ensaios sul brasileiros de trigo do Rio Grande do Sul, em 1985.

bitstream/item/119646/1/FOL-02362.pdfTrabalho apresentado na XVIII Reunião da Comissão Sul Brasileira de Pesquisa de Trigo, Chapecó, 1986