Theta Phase Modulates Multiple Layer-Specific Oscillations in the CA1 Region

It was recently proposed that fast gamma oscillations (60--150 Hz) convey spatial information from the medial entorhinal cortex (EC) to the CA1 region of the hippocampus. However, here we describe 2 functionally distinct oscillations within this frequency range, both coupled to the theta rhythm during active exploration and rapid eye movement sleep: an oscillation with peak activity at ~80 Hz and a faster oscillation centered at ~140 Hz. The 2 oscillations are differentially modulated by the phase of theta depending on the CA1 layer; theta-80 Hz coupling is strongest at stratum lacunosum-- moleculare, while theta-140 Hz coupling is strongest at stratum oriens--alveus. This laminar profile suggests that the ~80 Hz oscillation originates from EC inputs to deeper CA1 layers, while the ~140 Hz oscillation reflects CA1 activity in superficial layers. We further show that the ~140 Hz oscillation differs from sharp wave--associated ripple oscillations in several key characteristics. Our results demonstrate the existence of novel theta--associated high-frequency oscillations and suggest a redefinition of fast gamma oscillations

Modelo de programação linear para seleção de pulverizadores agrícolas de barras Linear programming model to agricultural boom sprayer selection

A seleção de pulverizadores agrícolas que se adaptem às necessidades da propriedade, é um processo trabalhoso, sendo uma das etapas mais importantes dentro do processo produtivo. O objetivo do presente trabalho foi o de desenvolver e utilizar um modelo de programação linear para auxiliar na seleção de pulverizadores agrícolas de barras, baseado no menor custo horário do equipamento. Foram utilizadas as informações técnicas referentes a 20 modelos de pulverizadores disponíveis no mercado, sendo quatro autopropelidos, oito de arrasto e oito do tipo montado. A análise de sensibilidade dos componentes dos custos operacionais mostrou que as taxas de reparo e depreciação foram os fatores que mais interferiram na variação do custo horário do conjunto trator-pulverizador. O modelo matemático desenvolvido facilitou a realização da análise de sensibilidade que foi processada em um tempo muito pequeno.The selection process of agricultural machines is one of the most important stages of the productive process. The purpose of the present work was to develop and to test a linear programming model to aid in the decision of agricultural boom sprayer selection based on the cheapest hour-cost. The technical information about 20 sprayer models available in the market was used, where four were self-propelled, eight were trailed and eight were lift mounted sprayer. The sensibility analysis of the operational cost components showed that the repair and depreciation rates are the factors that most contribute to hour-cost variation of the sprayer-tractor group. The developed mathematical model facilitated the accomplishment of the sensibility analysis, which was processed in a very short time