On String Theory Duals of Lifshitz-like Fixed Points

We present type IIB supergravity solutions which are expected to be dual to certain Lifshitz-like fixed points with anisotropic scale invariance. They are expected to describe a class of D3-D7 systems and their finite temperature generalizations are straightforward. We show that there exist solutions that interpolate between these anisotropic solutions in the IR and the standard AdS5 solutions in the UV. This predicts anisotropic RG flows from familiar isotropic fixed points to anisotropic ones. In our case, these RG flows are triggered by a non-zero theta-angle in Yang-Mills theories that linearly depends on one of the spatial coordinates. We study the perturbations around these backgrounds and discuss the possibility of instability. We also holographically compute their thermal entropies, viscosities, and entanglement entropies.Comment: 47 pages, 4 figure

Eco-physiological interactions above and bellow ground in an agroforestry system of rubber trees (Hevea brasiliensis) and beans (Phaseolus vulgaris).

O presente trabalho teve por objetivo melhor compreender a competição por luz, água e outros fatores produtivos e sua utilização pela cultura de feijoeiro em sistema agroflorestal com seringueira em vista de seus rendimentos. Também foi quantificada a modificação do desempenho de ambas as culturas em função da mútua interação entre as árvores e cultura intercalar. O experimento foi instalado no campo experimental pertencente ao Departamento de Produção Vegetal - ESALQ/USP (22º42'30'' S, 47º38'00'' Oeste) em Piracicaba/SP, na forma de blocos casualizados com quatro repetições e quatro tratamentos, sendo estes: (i) Controle da seringueira (Hevea brasiliensis); (ii) Sistema agroflorestal de seringueira e feijoeiro (Phaseolus vulgaris) com lona plástica inserida numa trincheira no solo entre as culturas para evitar a competição entre as raízes das duas culturas; (iii) Sistema agroflorestal de seringueira e feijoeiro, permitindo competição entre raízes; (iv) Controle do feijoeiro (Phaseolus vulgaris), fora da influência das seringueiras. Foram realizados dois cultivos subsequentes, com semeadura de feijoeiro em 15/março/99 e 15/julho/99. Durante a realização do experimento efetuou-se a coletas de dados de crescimento e rendimento das plantas. As condições climáticas foram monitoradas por estação micrometeorológica automática. A cultura do feijoeiro foi analisada quanto ao seu crescimento em matéria seca, índice de área foliar, área foliar específica, e rendimento em relação à distância das árvores. As árvores de seringueira foram analisadas quanto ao seu crescimento através do perímetro do tronco, altura das árvores, largura da copa e da produção de borracha. De acordo com os dados experimentais obtidos podemos concluir que: (i) O sombreamento causado pelas árvores aos feijoeiros sempre diminuiu o rendimento destes, sendo este o principal fator de modificação de seu desempenho. (ii) Existe competição inter-específica abaixo do nível do solo e foi limitada a uma distância de aproximadamente 10 m. (iii) O SAF proposto foi mais produtivo que os monocultivos de seus componentes.This work aims to understand the competition for light, water and other productive factors and their use by the crops in an Agroforestry System (AFS) of rubber trees and beans. Also, the modified output of both crops were quantified as a function of the mutual interaction between trees and associated crop. The trial was located in the experimental field of the Department of Plant Production ESALQ/USP (22°42'30" S, 47°38'00" West) at Piracicaba, state of São Paulo. The experiment was designed in randomised blocks with 4 replications with the followings 4 treatments: (i) Rubber tree control (Hevea brasiliensis); (ii) Agroforestry System of rubber trees and beans with bellow grounds interactions avoided by a plastic sheet of 1.5 meters deep in a trench between both crops; (iii) Agroforestry System of rubber trees and beans with bellow grounds interactions and; (iv) Beans control (Phaseolus vulgaris), far form the influences of the rubber trees. Two subsequent beans crops were sowed on March 15, 1999 and July 15, 1999. During the field trial data of the growth and yield of both crops were collected. Climate conditions were monitored, using an automatic weather station. The growth of the beans crop was analysed by dry matter production, leaf area index, specific leaf area and yield, in relation to the distance from the rubber trees. The rubber trees were studied by considering its growth of the trunk perimeter, tree height, crown width and rubber yield. The conclusions were: i) Shading by the trees was the main factor to reduce growth and yield of beans; ii) Below ground competition was limited to the distance of 10m from the trees; iii) The AFS studied was more productive than the monocrops of its components