Extratores e disponibilidade de micronutrientes em solos antrópicos da Amazônia.

Editado por: Patrícia M. Santos, Edison B. pott, Alberto C. de Campos Bernardi, Ana Rita de A. Nogueira, Luciana C. de A. Regitano e Márcia Cristina de S. Oliveira

Carbono orgânico e substâncias húmicas na sucessão da floresta primária em seringais em solos de terra firme da Amazônia Ocidental.

A conversão da floresta primária na Amazônia por culturas de interesse econômico tem na sua maior parte, apresentado impactos relevantes neste agroecossistema, porém, com o aumento da população e da demanda por produtos do setor primário, futuramente sua ocupação se tornará necessária. Alternativas são importantes, uma delas é a exploração em monocultivos ou consorciados com seringais, planta nativa da região. Para isso, foi estudada uma cronosseqüência formada por uma floresta primária de referência (Manaus) e em áreas seringais plantados em 1999 (copa - híbridos de Hevea pauciflora ou Hevea Benthamiana com Hevea brasiliensis) - 6 anos, 1988 (copa - Hevea pauciflora) - 16 anos, 1986 (copa - Hevea pauciflora) - 18 anos, 1985 (copa - Hevea brasiliensis) - 19 anos, 1984 (copa - Hevea pauciflora) - 20 anos e 1960 (copa - Hevea brasiliensis) - 45 anos. Os resultados mostraram que a remoção da floresta ocasionou em diminuição média de 46% do estoque de matéria orgânica no solo, chegando esse valor, a 66% quando comparado com o plantio com 6 anos. O mesmo ocorreu com os ácidos orgânicos independentemente da idade do seringal. Palavras-chave: matéria orgânica do solo, frações orgânicas, Amazônia INTRODUÇÃ

String-like brane splitting in the context of f(T,B)f(T,B) gravity

In this work, the influence of the boundary term $B$ is analyzed in a string-like thick brane scenario in the gravity context $f(T, B)$. For that, three models of $f(T, B)$ are proposed, i.e., $f_1(T, B)=T+k{B}^{n}$, $f_2(T, B)=T+k(-T+B)^{n}$ and $f_3(T, B)=T+k_1T^2+k_2{B}^2$, where $n$, $k$ and $k_{1,2}$ are parameters that control the deviation from the usual teleparallelism. The first relevant result obtained was the appearance of a super-located tower in the core for energy density. Furthermore, the greater the influence of the boundary term, the new maximums and minimums appear in the energy density. All this indicates the emergence of capable structures from split to the brane. The second relevant result was obtained by analyzing the gravitational perturbations, where the effective potential presents the supersymmetric form of quantum mechanics, leading to well-localized massless modes.Comment: 18 pages, 7 captioned figure

Two Experimental Approaches of Looking at Buoyancy

In our teaching practice, we find that a large number of first-year university physics and chemistry students exhibit some difficulties with applying Newton's third law to fluids because they think fluids do not react to forces. (c) 2013 American Association of Physics Teachers

Guest Editorial

[Excerpt] The 13th European Meeting on Ferroelectricity (EMF-13) has welcomed participants to Portugal for the first time in the history of these meetings. EMF-13 was held, from 28th June to 3rd July 2015, in the Faculty of Sciences of the University of Porto. The conference has been organized by the group “Polarized Materials and Functional Nanostructures” of the Materials Physics Institute, IFIMUP-IN, (IN - Institute of Nanoscience and Nanotechnology), in the Physics and Astronomy Department of the Faculty of Sciences, University of Porto. The Local Organizing Committee included members of the Universities of Porto, Minho and Aveiro. Three hundred and sixty six attendees from thirty four countries in Europe, Asia, America, and Africa were fully registered at EMF-13 meeting. These participants took active part in the sessions and informal discussions that had place along the 5 days of the meeting. Five plenary talks, given by Vladimir Fridkin, David Field, Annette Bussmann-Holder, Manuel Bibes, and Stephen Rowley, sixty invited talks, and one hundred thirty five oral contributions covered a wide number of topics ranging from basic research to new characterization techniques or novel applications of ferroelectrics and related materials. Complementary to the program of the meeting, a one day satellite workshop on “Inelastic scattering in ferroic materials” took place on Sunday 28th. [...]info:eu-repo/semantics/publishedVersio