17 research outputs found

    Results from the Regional AUSTRAL VLBI Sessions for Southern Hemisphere Reference Frames

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    Since late 2011, more than 40 dedicated AUSTRAL VLBI sessions have been undertaken with the aim to strengthen the terrestrial and celestial reference frame in the southern hemisphere. In this program, the three 12-m antennas from the Australian AuScope array in Hobart (Tasmania), Katherine (Northern Territory) and Yarragadee (Western Australia) observe together with the new 15-m dish in Hartebeesthoek (South Africa) and the 12-m antenna in Warkworth (New Zealand). Recently, the planned observations have been greatly expanded, with 50 additional sessions planned until mid-2015, along with 3 continuous campaigns covering 15 days each. Independent scheduling at the Vienna University of Technology allows short-notice scheduling, optimized for strategies specific to each session. Presently, the aim of the AUSTRALs switches between geodesy, astrometry, and densification of the southern hemisphere celestial reference frame. All AUSTRALs are recorded with an increased data rate of 1 Gbps, allowing to compensate for the reduced sensitivity of the generally smaller dish size. We give an overview of the AUSTRAL observing program and summarize the results so far. The performance is validated against standard global VLBI sessions and we identify the suitability of our global geodetic and astrometric products. Finally, we give an outlook on our future plans for the AUSTRAL observing program: this includes improved operations through the application of dynamic scheduling techniques, studying the use of sibling telescopes available at two sites within the AUSTRAL array (Hobart and Hartebeesthoek), and investigating source structure effects through astrometric imaging and source monitoring

    Results from the Regional AUSTRAL VLBI Sessions for Southern Hemisphere Reference Frames

    No full text
    Since late 2011, more than 40 dedicated AUSTRAL VLBI sessions have been undertaken with the aim to strengthen the terrestrial and celestial reference frame in the southern hemisphere. In this program, the three 12-m antennas from the Australian AuScope array in Hobart (Tasmania), Katherine (Northern Territory) and Yarragadee (Western Australia) observe together with the new 15-m dish in Hartebeesthoek (South Africa) and the 12-m antenna in Warkworth (New Zealand). Recently, the planned observations have been greatly expanded, with 50 additional sessions planned until mid-2015, along with 3 continuous campaigns covering 15 days each. Independent scheduling at the Vienna University of Technology allows short-notice scheduling, optimized for strategies specific to each session. Presently, the aim of the AUSTRALs switches between geodesy, astrometry, and densification of the southern hemisphere celestial reference frame. All AUSTRALs are recorded with an increased data rate of 1 Gbps, allowing to compensate for the reduced sensitivity of the generally smaller dish size. We give an overview of the AUSTRAL observing program and summarize the results so far. The performance is validated against standard global VLBI sessions and we identify the suitability of our global geodetic and astrometric products. Finally, we give an outlook on our future plans for the AUSTRAL observing program: this includes improved operations through the application of dynamic scheduling techniques, studying the use of sibling telescopes available at two sites within the AUSTRAL array (Hobart and Hartebeesthoek), and investigating source structure effects through astrometric imaging and source monitoring

    Tipos de enxertia em diferentes idades de plantas de maracujazeiro

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    A propagação vegetativa do maracujazeiro pode propiciar a obtenção de mudas e pomares uniformes, com uso de porta-enxertos com boas características, como tolerância às doenças do solo. O trabalho teve como objetivo estudar métodos de enxertia nas diferentes idades das plantas de maracujazeiro após emergência. O Experimento foi conduzido no Setor de Fruticultura da Universidade Federal de Lavras (UFLA), em Lavras-MG, sob telado com 50% de sombreamento. O delineamento experimental utilizado foi em blocos casualizados, no esquema fatorial 2x4, dois métodos de enxertia (fenda cheia e inglês simples) e quatro épocas de enxertia (15; 25; 35 e 45 dias após a emergência). Foram avaliadas: porcentagem de pegamento, número de folhas, altura e diâmetro das plantas. Conclui-se que, na enxertia do maracujazeiro-azedo sobre o doce, tanto no método de garfagem fenda cheia quanto para inglês simples, a melhor época para realização é aos 15 dias após a emergência, apresentando um índice de pegamento de 98% em ambos os métodos
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