37,209 research outputs found

    Binary open clusters in the Milky Way: photometric and spectroscopic analysis of NGC 5617 and Trumpler 22

    Get PDF
    Using photometry and high resolution spectroscopy we investigate for the first time the physical connection between the open clusters NGC 5617 and Trumpler 22. Based on new CCD photometry we report their spatial proximity and common age of ~70 Myr. Based on high resolution spectra collected using the HERMES and UCLES spectrographs on the Anglo-Australian telescope, we present radial velocities and abundances for Fe, Na, Mg, Al, Si, Ca and Ni. The measured radial velocities are -38.63 +/-2.25 km/s for NGC 5617 and -38.46 +/-2.08 km/s for Trumpler 22. The mean metallicity of NGC 5617 was found to be [Fe/H] =-0.18 +/-0.02 and for Trumpler 22 was found to be [Fe/H] = -0.17 +/-0.04. The two clusters share similar abundances across the other elements, indicative of a common chemical enrichment history of these clusters. Together with common motions and ages we confirm that NGC 5617 and Trumpler 22 are a primordial binary cluster pair in the Milky Way.Comment: 7 pages, 3 figure, accepted by MNRA

    Manipulation of Magnetic Skyrmions by Superconducting Vortices in Ferromagnet-Superconductor Heterostructures

    Full text link
    Dynamics of magnetic skyrmions in hybrid ferromagnetic films harbors novel physical phenomena and holds promise for technological applications. In this work, we discuss the behavior of magnetic skyrmions when coupled to superconducting vortices in a ferromagnet-superconductor heterostructure. We use numerical simulations and analytic arguments to reveal broader possibilities for manipulating the skyrmion-vortex dynamic correlations in the hybrid system, that are not possible in its separated constituents. We explore the thresholds of particular dynamic phases, and quantify the phase diagram as a function of the relevant material parameters, applied current and induced magnetic torques. Finally, we demonstrate the broad and precise tunability of the skyrmion Hall-angle in presence of vortices, with respect to currents applied to either or both the superconductor and the ferromagnet within the heterostructure

    Evolution of deforestation in the Brazilian Pantanal and surroundings in the timeframe 1976 - 2008.

    Get PDF
    Maps elaborated from five different periods were recovered and inserted within a single GIS. Considering these maps, the evolution of deforestation in the Pantanal and its surroundings in Brazil was analyzed for the last 32 years and scenarios were described for the timeframe 2010-2050. The results for the different BAP (Floodplain and Plateau), BAP (Mato Grosso and Mato Grosso do Sul States), BAP (Biomes: Pantanal, Cerrado and Amazon). Until 2008, the deforestation on the Pantanal floodplain affected 12,14% of its area, while on the Plateau 58,90% were concerned. The actual deforestation percentages indicate that, if no effective control actions are taken, the natural vegetation from this region could be eliminated till 2050. As an instrument for the effective deforestation control, we suggest the implantation of a deforestation monitoring system on the river basin of the Upper Paraguay, based on information technology.Número especial

    Época de semeadura do milho para a região de Sete Lagoas, MG, baseada na probabilidade de ocorrência de períodos secos e chuvosos.

    Get PDF
    O objetivo deste estudo foi determinar as probabilidades de ocorrência de períodos secos e chuvosos na região de Sete Lagoas, MG, a partir de uma série de 66 anos de dados diários de precipitação pluvial, visando subsidiar a definição da melhor data de semeadura do milho. Foram considerados dias secos aqueles que apresentaram precipitação inferior à evapotranspiração do milho, ETmilho. O estudo foi realizado para as fases de floração e enchimento de grãos a partir de sete datas de semeadura DS (01/10, 16/10, 31/10, 15/11, 01/12, 16/12 e 31/12). As chances de ocorrência dos períodos secos e chuvosos foram estimadas mediante o uso da cadeia de Markov. A probabilidade de ocorrência de dias secos foi sempre superior à de dias chuvosos. As maiores possibilidades de ocorrência de dias secos foram observadas entre as DS 15/11 e 31/12. A maior probabilidade de ocorrência de dias chuvosos foi registrada na DS 01/10. Considerando o ciclo médio estudado (para a fase mais crítica do milho), a combinação de menor chance de períodos secos com a de dias chuvosos indica que as melhores datas para iniciar a semeadura de sequeiro seriam as deDS 01/10 e 16/10

    Production, breeding and potential of cowpea crop in Brazil.

    Get PDF
    About 50 years ago cowpea was reported as a relatively minor tropical legume. However, in the last years, it has been emerging as one of the most important food legume of the 21st century (SINGH, 2010). Brazil is not out of this panorama. Brazilian agriculture is undergoing major technological changes and, in addition, globalization in agribusiness has caused impacts on the production chain of several crops, particularly those heavily dependent on the use of a large volume of agricultural inputs, mainly fertilizers and pesticides. Such crops have had a higher production cost each year. On the other hand, this situation has brought new opportunities. Business farmers have sought new alternatives for their production arrangements. In this context cowpea constitutes one of the best options.bitstream/item/85620/1/Doc-216-Production.pd
    corecore