1,504 research outputs found

    Learning with multiple representations: An example of a revision lesson in mechanics

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    We describe an example of learning with multiple representations in an A-level revision lesson on mechanics. The context of the problem involved the motion of a ball thrown vertically upwards in air and studying how the associated physical quantities changed during its flight. Different groups of students were assigned to look at the ball's motion using various representations: motion diagrams, vector diagrams, free-body diagrams, verbal description, equations and graphs, drawn against time as well as against displacement. Overall, feedback from students about the lesson was positive. We further discuss the benefits of using computer simulation to support and extend student learning.Comment: 10 pages, 5 figures, 2 tables http://iopscience.iop.org/0031-912

    Avaliação de leguminosas com potencial de uso para adubos verdes nos tabuleiros litorâneos do Piauí.

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    Green manure may lead to physical, chemical, and biological improvements to the soil. However, the information on its use in the Brazilian Northeast is scarce. The aim of this study was to assess the phenological cycle and phytomass productivity of seven legume species. This study was conducted in the second semester of 2015 in a completely randomized design with seven treatments and four replications

    Coupling palaeobiology and geochemistry from the Holocene of the southern Adriatic Sea (Gulf of Manfredonia, Italy): Shelf facies patterns and eutrophication trends

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    The combined use of the meiofauna (benthic foraminifers and ostracods) and geochemical data from three cores, recovered in distinct bathymetric sectors of the southern Adriatic shelf (Apulia, SE Italy), provides new insights on the relationships between shallow-marine environments, sediment fluxes and eutrophication trends over the last ~7000 years. The stratigraphic distribution of meiofauna assemblages allows distinguishing a variety of facies associations, accumulated at proximal (Manfredonia Gulf), intermediate and distal shelf sectors. Spatial-temporal facies trajectories mainly reflect changes in fluxes of fine-grained, inorganic and organic particles at the seafloor. Major palaeoenvironmental shifts are paralleled by stratigraphic variations of Cr-Ni values, which represent effective provenance tracers for the Adriatic region. The correlation between the meiofauna content and trace-metal concentrations documents the link between the type of substrate (organic matter-OM and grain-size) and sediment provenance along the bathymetric profile and through time. After 6000 yr B.P., the gulf, partly sheltered by the Gargano Promontory, experienced the first increase in OM fluxes (transition from open-bay to prodelta). This turnaround occurred under the progressive change in sediment supply from southern Apennine source-rocks, poor in trace metals, to a mixed contribution including northern sources, enriched in chromium and nickel (mafic/ultramafic rocks of the Po River catchment) via the SSE-directed longshore drift. Alongside, prodelta clays in lateral transition to mud-belt deposits accumulated in the adjacent open shelf under the steady influence of the longshore drift. Finally, since ~2000 yr B.P. a pervasive subaqueous delta system developed across the study area in response to increased sediment load by Po + Apennine rivers, likely induced by enhanced anthropic pressure during Roman times. This study highlights the key role played by the sediment routing system, coastal morphology and human land-use on shelf facies patterns and eutrophication trends, even in areas hundreds of km away from the main fluvial mouths

    Manejo integrado da broca-do-olho-do-coqueiro Rhynchophorus palmarum L. (Coleoptera: Curculionidae).

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    O gênero Rhynchophorus é relatado causando dano em palmeiras em quase toda a região tropical do Planeta. Três espécies ocorrem nas Américas: R. cruentatus na Florida, costa sudeste dos Estados Unidos e Bahamas; R. palmarum no México, Américas Central e do Sul, e sul das Antilhas; e R. ritcheri no Peru (GIBLIN-DAVIS et al., 2013).bitstream/item/125475/1/Cot-141.pd

    Aspectos biológicos e manejo da Cochonilha-transparente aspidiotus destructor e do Pulgão-preto Cerataphis Lataniae em coqueiro.

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