A reprodução de experimentos científicos em laboratório é frequentemente difícil, devido ao número de alunos por turma, insuficiência de equipamentos ou à incompatibilidade do tempo necessário à realização dos experimentos. Por outro lado, o medo de manusear circuitos elétricos é sem dúvida uma das causas do baixo rendimento dos alunos em eletricidade. Diante dessa perspectiva, propusemos o desenvolvimento de roteiros experimentais de Eletrodinâmica utilizando os simuladores virtuais do PhET (Physics Education Technology Project), da Universidade do Colorado (EUA) como metodologia de ensino. O objetivo da atividade foi utilizar a simulação como ferramenta facilitadora da aprendizagem sobre o funcionamento de um circuito elétrico. A proposta foi aplicada a alunos do 3º ano do Curso Técnico de Mineração do Instituto Federal de Educação, Ciência e Tecnologia do Amapá e envolveu a interação em um ambiente virtual, tendo como suporte conceitos decorrentes da perspectiva de Vygotsky. Para a construção e análise de dados trabalhou-se com levantamento bibliográfico, coleta de dados por meio de testes, roteiro de entrevista e observação in loco. Os resultados obtidos indicaram boa aceitação da proposta, na medida em que o uso da tecnologia teve um sentido transformador na prática pedagógica, ou seja, que o PhET não foi usado simplesmente para reproduzir o modelo tradicional de ensino, mas para criar situações de aprendizado sobre Eletrodinâmica. A atividade contribuiu para fortalecer uma visão construtivista do processo de aprendizagem, destacando o forte envolvimento dos alunos na construção do conhecimento ao integrar ideias prévias às ferramentas de aprendizagem.

Aquaponics is a science that integrates animal aquatic production with vegetable culture in recirculating water systems. The performance of an aquaponics system using constructed semi-dry wetland with lettuce (Lactuca sativa L.) planted on treating wastewater of culture of shrimp Macrobrachium amazonicum was evaluated. Each aquaponics module consisted in four culture tanks (1 m 3 tank −1), conical sedimentation tank (0.1 m 3), circular holding tank (0.2 m 3), and constructed semi-dry wetland (0.2 m × 1.0 m × 4.0 m). Post larvae (PL) shrimps with an initial average mass of 314 ± 4.75 mg were stocked at density treatments in quadruplicate: (A) 40 shrimps m −2 , (B) 80 shrimps m −2 , and (C) 120 shrimps m −2. Our results showed the average final mass of shrimps had a slight reduction at the density 80 and 120 shrimps. However, it did not differ significantly between the treatments. The ultimate survival and productivity were higher in density 80 and 120 shrimps. The maximum biomass productivity occurred at the treatment with density 120 shrimps. The aquaponics recirculation system using constructed semi-dry wetlands with lettuce adequately treated the water at the densities tested. Various water quality parameters were deemed suitable for shrimp culture, but for lettuce not, especially the temperature. The shrimp density was inappropriate which limited the system to accumulate and increase the concentration of nutrients to vegetables with lessening the yield. Nonetheless, the system with higher density has higher nutrient content that plants demonstrated significantly better growth and yield. The results showed the potential use of organics waste generated in a family lettuce hydroponic production, but for a commercial production is indicated supplementation with nutrients like calcium, magnesium, and potassium in the water.

Macrobrachium amazonicum is a shrimp species distributed in freshwater habitats of Neotropical regions and is of great importance for the Amazonian economy. This study evaluated the effects of temperature increase on the survival and growth of M. amazonicum. For this, we distributed 360 M. amazonicum juveniles in 70 L tanks, and carried out a 90-day experiment with three treatments (T0: 28 ± 0.5 °C, or room temperature; T1: 30 ± 0.2 °C; T2: 32 ± 0.2 °C), using 4 replicate tanks each with 30 individual shrimp. Culture-tanks were connected to a recirculation system with biofiltration and constant aeration. Animals were fed twice a day using shrimp pelleted commercial food. After 90 days of trial, the total length and body mass gain of the animals cultured at room temperature was 78% and 433%, respectively. The specific growth rate, condition factor, weight gain, and length and survival of animals cultured at 30 and 32 °C were lower than those cultivated at 28 °C, and feed conversion was higher. Therefore, water temperature of 30 and 32 °C may compromise growth and survival of M. amazonicum during cultivation, none of the extreme temperatures may be recommended in practice.

This study has investigated the influence of unilateral eyestalk ablation on the survival, molting frequency, fecundity, reproductive output, and fertility of M. amazonicum females. We divided 96 females into with ablation and without ablation groups with six replicates. Water quality, growth, survival rate, intermolt period, molts number, and ovigerous females over a 90-day period were monitored. Unilateral eyestalk ablation reduced intermolt period by 30% and increased molts number, ovigerous females, and reproductive output. Our findings indicate that unilateral eyestalk ablation positively influences reproduction in M. amazonicum and is appropriate for females of this species having a body length of ≥ 70 mm.

This study aimed to determine artificial semi-dry wetlands' performance to wastewater treatment from fish farming and Lactuca sativa production in an aquaponics system. This trial model observed the effects of different stocking biomass on the growth rate of Colossoma macropomum and yield of two L. sativa varieties. A factorial design consisting of three fish density treatments in quadruplicate and two Lettuces variety was used. Nine hundred and sixty fingerlings with 8.35 ± 0.91 g were stocked at three stocking biomass treatments in quadruplicate: 40 fingerlings or 334 g m −3 ; 80 fingerlings 668 g m −3 ; 120 fingerlings or 1002 g m −3 . Delice American Lettuce and Purple Crested Lettuce were cultured in the semi-dry wetlands. The final mass (g), consumed food, feed conversion ratio, and yield of fingerling were statistically different between the tested densities, but survival did not. The artificial semi-dry wetlands were efficient on water treatment and the recovery of nutrients in all fish densities trials, and it has potential as support for lettuce production. The recovery of nutrients was shown on the increment of the number of leaves, total fresh mass (g), and lettuces yield by area (kg m −2 ) in both varieties of plants tested. Precocious flowering in 30% of lettuce varieties, incidence of mealybug and whitefly, temperature and deficiency of calcium and magnesium were factors that may have compromised the full lettuce development. The aquaponics system efficiently treated the fish effluent at the densities tested, being appropriate for fish farming and lettuces production.