Avaliação de diferentes métodos de destruição de restos culturais do algodoeiro.

Resumo: O presente trabalho objetivou avaliar, nas safras agrícolas de 1996/97 e 1997/98, diferentes métodos de destruição dos restos culturais do algodoeiro, em campo de produção de sementes e em condições de sequeiro, no município de Palmas de Monte Alto, BA. Foram determinados a eficiência de arranquio, o tempo operacional e os custos de diferentes métodos, como arranquio manual, arrancadores tratorizados, gradagem com grade aradora, aração com arado de disco e roço, de forma isolada e associados aos dois últimos métodos. Pelos resultados obtidos pode-se concluir que, para as condições de cultivo do algodoeiro em sequeiro na região Sudoeste da Bahia, os métodos mais eficientes para a destruição dos restos culturais do algodoeiro foram: o arranquio manual com enxadão, a aração de forma isolada e o roço seguido de uma aração com arado de disco, que proporcionaram uma percentagem de arranquio de plantas acima de 97% e de rebrota inferior a 2%. Abstract: A field experiment was conducted in 1996/97 and 1997/98, in Palmas de Monte Alto, BA, Brazil, to investigate the efficiency of different methods of cotton stalk destruction under dry-farming conditions. The efficiency, operational timing, and cost of cotton stalk destruction of methods such as manual hoeing, stalk clearing machines, disk harrow, plowing with a disk plow and a cutter-shredder alone and associated with the last two methods were evaluated. The results showed that for the cultivation conditions of Southwest Bahia, the most efficient methods were: manual hoeing, plowing with disk plow and the association of plowing with disc plow and cutter-shredder. In these methods, 97% of crop residue destruction and a regrowth of less than 2% were registered.Título em inglês: Evaluation of different methods of cotton stalk destruction

Adubação nitrogenada e densidade de semeadura na cultura do milho em plantio direto no Sudeste paraense.

O objetivo do estudo foi avaliar a eficiência da adubação nitrogenada em relação à população de plantas de milho sob o sistema plantio direto no município de Paragominas, no Estado do Pará. O delineamento experimental utilizado para cada experimento foi em blocos casualizados, em esquema fatorial 4 x 4, com três repetições. Assim, avaliou-se na cultura do milho a influência do espaçamento, da densidade populacional e de doses de nitrogênio no teor de nitrogênio nas folhas, número de grãos por espiga, massa de 1.000 grãos e produtividade. O trabalho foi instalado no ano agrícola 2014/2015 e constou de tratamentos representados pela combinação de quatro doses de nitrogênio em cobertura: 0, 60, 120 e 180 Kg.haˉ¹, com quatro densidades de plantio: 45.000; 55.000; 65.000 e 75.000 plantas.haˉ¹. O aumento nas doses de nitrogênio em cobertura promoveu acréscimo no teor de N foliar, no número de grãos por espiga, na massa de 1.000 grãos e na produtividade, independente do local, espaçamento e na densidade de plantas

Redução de custos na produção de mudas micropropagadas de bananeira cv. Williams.

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Preparation and control of a cavity-field state through atom-driven field interaction: towards long-lived mesoscopic states

The preparation of mesoscopic states of the radiation and matter fields through atom-field interactions has been achieved in recent years and employed for a range of striking applications in quantum optics. Here we present a technique for the preparation and control of a cavity mode which, besides interacting with a two-level atom, is simultaneously submitted to linear and parametric amplification processes. The role of the amplification-controlling fields in the achievement of real mesoscopic states, is to produce highly-squeezed field states and, consequently, to increase both: i) the distance in phase space between the components of the prepared superpositions and ii) the mean photon number of such superpositions. When submitting the squeezed superposition states to the action of similarly squeezed reservoirs, we demonstrate that under specific conditions the decoherence time of the states becomes independent of both the distance in phase space between their components and their mean photon number. An explanation is presented to support this remarkable result, together with a discussion on the experimental implementation of our proposal. We also show how to produce number states with fidelities higher than those derived as circular states

Mixed gastric carcinomas show similar chromosomal aberrations in both their diffuse and glandular components

Gastric cancer is one of the most frequent malignancies in the world. Nonetheless, the knowledge of the molecular events involved in the development of gastric carcinoma is far from complete. One of the hallmarks of gastric cancer is chromosomal instability resulting in abnormal DNA copy number changes throughout the genome. Mixed gastric carcinomas constitute a rare histological entity, containing the two main histological phenotypes (diffuse and intestinal). Very little is known about the underlying mechanisms of phenotypic divergence in these mixed tumours. To the best of our knowledge only E-Cadherin mutations were implicated so far in the divergence of these tumours and nothing is known about the involvement of chromosome copy number changes in the two divergent histological components. In this study, we compared the DNA copy number changes, in the two different components (diffuse and intestinal) of mixed gastric carcinomas by microarray - comparative genomic hybridisation (array CGH). The analysis of 12 mixed gastric carcinomas showed no significant differences in array CGH profiles between the diffuse and intestinal components of mixed carcinomas. This supports the idea that the phenotypic divergence within mixed gastric carcinomas is not caused by DNA chromosomal aberrations.Portuguese Foundation for Science and Technology (FCT), grant POCTI/CBO/ 41179/2001 and by Dutch Cancer Society grant – KWF2004-305