RESUMO A vazão ótima da solução nutritiva no sistema hidropônico pode nutrir melhor as plantas, possibilitando maior e mais rápido crescimento da alface. Entretanto, a vazão também interfere no consumo de energia elétrica, por isso são necessárias mais pesquisas, principalmente sobre o efeito da taxa de fluxo (vazão), no acúmulo de nutrientes e produção de alface americana. Diante do exposto, objetivou-se com esta pesquisa, estudar a nutrição e a produção de alface americana em função da vazão da solução nutritiva em sistema hidropônico NFT. Os tratamentos utilizados constaram da aplicação de solução nutritiva nas vazões de 0,5; 1; 2 e 4 litros por minuto (L/min) em cada canal de cultivo. Cada tratamento possuiu cinco repetições, compostas por 15 plantas cada. A vazão em sistemas hidropônicos para produção de alface americana altera o desempenho técnico da cultura. Devido ao maior acúmulo de nutrientes na parte aérea e eficiência de utilização destes elementos, a maior produção (g/planta) de alface americana é obtida com a vazão da solução nutritiva de 1 L/min.

ABSTRACT The optimum flow rate of nutrient solution in hydroponic system can better nourish the crops, allowing healthy and faster growth of lettuce. However, flow also interferes with electric power consumption, so further researches are necessary, mainly on the effect of flow rate, nutrient accumulation and lettuce production. In this context, the aim of this study was to evaluate nutrition and production of head lettuce in relation to the nutrient solution flow in NFT hydroponic system. The treatments consisted of nutrient solution application at the flow rates 0.5; 1; 2, and 4 liters per minute in each cultivation channel. Five replicates per treatment consisted of 15 plants each. The flow in hydroponic systems to produce head lettuce alters the technical performance of the crop. Due to the greater nutrient accumulation in shoot and use efficiency of these elements, the highest production (g/plant) of head lettuce was obtained with a flow rate of 1 L/min of the nutrient solution.

Zinc oxide, an n-type semiconductor, has been used as photocatalyst for contaminated water purification by organic compounds. The addition of a p-type semiconductor as copper oxide could increase the catalytic efficiency through the p-n junction in order to decrease the electron-hole recombination. In this work, zinc and copper oxides containing 1.0, 3.0, and 5.0 % of copper were prepared by manual grinding, followed by heat treatment at 300°C during 5 h. The zinc oxide and copper oxide mixture as well as their precursors were characterized by x-ray diffraction, diffuse reflectance, scanning electron microscopy, and x-ray fluorescence. The photocatalytic efficiency was verified by the direct red 80 tetraazodye decolorization using UV radiation under pseudo-first order conditions at natural pH (7.5-8.0) and 30 °C. The highest photocatalytic activity occurred to the semiconductor containing 1.0 % copper oxide, whose decolorization rate constant was equivalent to 6.40×10-2 min-1, that is, 17.4 % larger in comparison to ZnO, 5.45×10-2 min-1.

Aneurismas situados junto à artéria carótida intracraniana proximal (entre seio cavernoso e artéria comunicante posterior) e ao nível do complexo comunicante anterior podem apresentar dificuldades técnicas relacionadas ao acesso apropriado sem retração cerebral excessiva. Em uma série de 15 pacientes os autores mostram o uso do acesso crânio-orbital, utilizado inicialmente para abordagem a tumores da base do crânio, para esses subgrupos de aneurismas. Discutem suas vantagens em minimizar retração, melhor orientação anatômica, evitar ressecção de tecido neural e facilitar remoção óssea. Não foi identificada qualquer complicação devida ao acesso descrito.

Aneurysms arising at the proximal intracranial carotid artery (between cavernous sinus and posterior communicating artery) and at the anterior communicating complex may present with technical difficulties regarding appropriate access without excessive brain retraction. In a series of 15 patients the authors show the use of the cranio-orbital approach, formerly designed in the access of skull base tumors, for these subgroups of aneurysms. They discuss the advantages of a basal avenue in minimizing brain retraction, better anatomical orientation, obviation of tissue ressection and easier extra-dural bone removal. It was not identified any complication due to the described approach.