The classical double copy for Taub-NUT spacetime

The double copy is a much-studied relationship between gauge theory and gravity amplitudes. Recently, this was generalised to an infinite family of classical solutions to Einstein's equations, namely stationary Kerr-Schild geometries. In this paper, we extend this to the Taub-NUT solution in gravity, which has a double Kerr-Schild form. The single copy of this solution is a dyon, whose electric and magnetic charges are related to the mass and NUT charge in the gravity theory. Finally, we find hints that the classical double copy extends to curved background geometries.Comment: 13 pages, no figures. Minor edits to match journal versio

Nonlinear Relativistic and Quantum Equations with a Common Type of Solution

Generalizations of the three main equations of quantum physics, namely, the Schr\"odinger, Klein-Gordon, and Dirac equations, are proposed. Nonlinear terms, characterized by exponents depending on an index $q$, are considered in such a way that the standard linear equations are recovered in the limit $q \rightarrow 1$. Interestingly, these equations present a common, soliton-like, travelling solution, which is written in terms of the $q$-exponential function that naturally emerges within nonextensive statistical mechanics. In all cases, the well-known Einstein energy-momentum relation is preserved for arbitrary values of $q$

Zoneamento agroclimático para a pimenteira-do-reino no Estado do Pará.

bitstream/item/28310/1/Doc321.pdfDisponível também on-line

Utilização de CO2 como meio de contraste na angiografia

info:eu-repo/semantics/draf

Resposta ao risco de complicações associadas à biópsia trantorácica por tomografia computorizada

info:eu-repo/semantics/draf

Growth of different fruit tree species in silvopastoral systems during the establishment phase.

EN-US: The benefits of integrating agricultural components into silvopastoral systems are widely known, but the limited knowledge about ecological processes in the establishment phase impedes the use of this technology. The objective of this study was to evaluate interactions between fruit tree species and the sward layer under canopies of trees in the establishment phase of silvopastoral systems in Mato Grosso, Brazil. The experiment was implemented in October 2013, with an evaluation period from January to July 2015. The systems were composed of eight fruit trees intercropped with Tifton 85 grass. A completely randomized block design was adopted, with two replications per area per treatment. We evaluated the agronomic performance of the fruit trees, the categories of the light environment, and the plant accumulation under the canopies. The acerola fruit trees of the variety Roxinha had higher Leaf area index (LAI) and Light interception (LI) values, showing a denser canopy with small porosity and the lowest light quality available to the plants beneath the canopy (lower red/far-red ratio), thereby decreasing plant accumulation under trees. The guava fruit trees showed higher growth rates than the other fruit trees, but lower LAI and LI values and a higher red/far-red ratio, allowing higher plant growth under the canopy. Cajá trees showed a similar behavior; however, this species is deciduous, which limits its potential use in integrated systems. Banana and coconut trees were highly dependent on irrigation during the dry season. The remaining species showed an adequate growth and potential to control plant species growth under their canopies. | PT-BR: Os benefícios de integrar os componentes agrícolas já são bastante conhecidos, porém o conhecimento sobre os processos ecológicos da competição das plantas ainda é uma barreira para essa tecnologia. O objetivo deste estudo foi avaliar a interação entre espécies fruteiras e a vegetação sob suas copas na fase de estabelecimento de sistemas silvipastoris no Mato Grosso, Brasil. O experimento foi implantado em 2013 e avaliado em 2015. Estes sistemas foram compostos por oito espécies de fruteiras consorciadas com Tifton-85. O delineamento experimental foi em blocos completos casualizados com duas repetições de área por tratamento. Foi avaliado o desempenho agronômico das espécies fruteiras, caracterização do ambiente luminoso e o acumulo de material vegetal sob as copas. A aceroleira Roxinha apresentou os maiores valores de índice de área foliar (IAF) e interceptação luminosa (IL) devido a um dossel mais denso com baixa porosidade e a menor qualidade de luz disponível sob as copas das árvores (menor relação vermelho/vermelho distante – V/Vd), condicionando a uma redução no acúmulo de material vegetal sob as copas. As goiabeiras cresceram mais do que as outras espécies, contudo apresentaram os menores valores de IAF e IL e alta relação V/Vd, permitindo a presença de mais plantas sob sua copa. Cajazeira demonstrou resposta similar, contudo esta espécie é decídua, podendo apresentar um potencial mais limitado em sistemas integrados. Bananeira e coqueiro mostraram uma grande dependência de irrigação durante a estação seca. As demais espécies apresentaram um crescimento adequado e potencial para controlar o crescimento das plantas sob suas copas

Leaf Appearance Rate in \u3ci\u3eBrachiaria decumbens\u3c/i\u3e Grown in Nitrogen and Potassium Rates

A greenhouse experiment was carried out with Brachiaria decumbens Stapf. cv. Basilisk grown in nutrient solution. Five nitrogen rates (42; 140; 238; 336 and 434 mg/L) and three potassium rates (78; 234 and 390 mg/L) were studied in a factorial experiment, in a randomized complete block design, with four replications. Green leaf number was evaluated in six times in the first period of growth (27, 30, 33, 36, 39 and 42 days after transplanting) and nine times in the second period (45, 48, 51, 54, 57, 60, 63, 66 and 69 days after transplanting). Data was registered in three plants per pot. The average green leaf number per tiller changed significantly (P\u3c 0.01) with nitrogen rates in the two growth periods. Leaf appearance rate was higher at nitrogen rates of 336 or 434 mg/L

Theory of 2δ\delta-kicked Quantum Rotors

We examine the quantum dynamics of cold atoms subjected to {\em pairs} of closely spaced $\delta$-kicks from standing waves of light, and find behaviour quite unlike the well-studied quantum kicked rotor (QKR). Recent experiments [Jones et al, {\em Phys. Rev. Lett. {\bf 93}, 223002 (2004)}] identified a regime of chaotic, anomalous classical diffusion. We show that the corresponding quantum phase-space has a cellular structure, arising from a unitary matrix with oscillating band-width. The corresponding eigenstates are exponentially localized, but scale with a fractional power, $L \sim \hbar^{-0.75}$, in contrast to the QKR for which $L \sim \hbar^{-1}$. The effect of inter-cell (and intra-cell) transport is investigated by studying the spectral fluctuations with both periodic as well as `open' boundary conditions.Comment: 12 pages with 14 figure