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

Cognition-induced modulation of serotonin in the orbitofrontal cortex: A controlled cross-over PET study of a delayed match-to-sample task using the 5-HT2a receptor antagonist [18F]altanserin

Behavioral and cellular studies indicate that serotonin interacting with the 5-HT2a receptor (5-HT2aR) is involved in cognitive processes supporting working memory (WM). However, 5-HT receptor neuroimaging studies directly relating WM-induced neuronal activations to concomitant changes in the availability of 5-HT receptors as a functional measure for serotonin release are lacking. This controlled cross-over PET study aimed to identify brain regions with WM-induced changes in the binding potential (BP(nd)) of the 5-HT2aR antagonist [(18)F]altanserin. Ten young males underwent a delayed match-to-sample task using photographs of faces and a control task. The BP(nd)s for both conditions were calculated by applying Ichise's noninvasive plot. Statistics were performed with the SPM toolbox statistical nonparametric mapping (SnPM3) particularly suited for analyzing whole-brain PET data in an exploratory way. A higher BP(nd) for [(18)F]altanserin during WM versus control was found in the orbitofrontal cortex (OFC) pointing towards an increased [(18)F]altanserin/5-HT2aR interaction in OFC while BP(nd) decreases during WM were not found. Furthermore, no BP(nd) changes in regions known from functional neuroimaging studies to be more specifically involved in WM were identified. These findings may suggest that the increased [(18)F]altanserin BP(nd) under WM challenge and hence the increased availability of 5-HT2aR reflects a decrease in local OFC serotonin. As the OFC plays a prominent role in decision-making and supports cognitive processes related to the central executive functions of WM it might be modulated by the serotoninergic system via the 5-HT2aR in order to support and optimize basic cognitive functions

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