445 research outputs found

    Atividade amilolítica e qualidade fisiológica de sementes armazenadas de milho super doce tratadas com ácido giberélico.

    Get PDF
    O uso de reguladores de crescimento na fase de germinação melhora o desempenhodas plântulas, acelerando a velocidade de emergência e realçando o potencial das sementes devárias espécies, mesmo sob condições adversas. Este trabalho teve como objetivo avaliar ainfluência do ácido giberélico na atividade amilolítica e no vigor de sementes armazenadas demilho super doce. O experimento foi conduzido nos Laboratórios de Análise de Sementes doDepartamento de Produção Vegetal/FCA e no Laboratório de Bioquímica de Plantas doDepartamento de Química e Bioquímica/IB da Universidade Estadual Paulista (UNESP/Botucatu),entre os meses de julho e setembro de 2001, onde foram feitas as avaliações da qualidade fisiológica,através dos testes de germinação, vigor e bioquímicos. Sementes de milho super doce da cultivarDO-04, foram acondicionadas em sacos de papel e armazenadas por oito meses em câmara seca(40% UR). Após este período, foram colocadas para germinar em rolos de papel toalha, embebidoscom GA3 nas concentrações zero; 50; 100; 150 e 200mg.L-1. Foram avaliadas a germinação, vigore atividade amilolítica das sementes. As sementes submetidas à pré-embebição em solução de50mg.L-1 de ácido giberélico, apresentaram maior germinação e vigor, menor teor de proteínastotais e maior atividade amilolítica

    Tolerância de cultivares de milho à acidez do solo e eficiência de resposta à calagem

    Get PDF
    A field experiment was conducted on an alic dystrophic latosol which was not cultivated before, aiming to characterize, the tolerance of maize (Zea mays L.)/ cultivars to soil acidity, evaluated through the percentage of saturation of exchangeable Al, and the efficiency to lime response. A randomized block experiment design with split-plots was used. Lime was added to the main plots at rates of 0.0, 3,5 and 13,5 t/ha and the 36 maize cultivars were sown in the sub-plots. Yield differences among cultivars, when compared from the absence of liming, showed a great variability to soil acidity tolerance. A great variability among cultivars to liming response was also observed, this being indicated by the regression coefficient of the linear equation for the relative yield as function of the percentage of, Al saturation, provided by the rates of lime applied. All cultivars were grouped into three classes, based on the yield average obtained from the absence of liming and the average of the regression coefficient of the equations. The classes are the following: 1. 1ow tolerance to soil acidity, with high efficiency to liming response; 2. high tolerance to soil acidity, with low efficiency to liming response; 3. high tolerance to soil acidity and high efficiency to liming response.Conduziu-se um experimento de campo em um Latossolo Roxo álico, nunca cultivado, com o objetivo de caracterizar a tolerância de cultivares de milho (Zea mays L.) à acidez do solo, avaliada através da percentagem de saturação de Al3+ trocável, e sua eficiência de resposta à calagem. Utilizou-se o delineamento experimental de blocos ao acaso com parcelas subdivididas; nas parcelas aplicou-se calcário nas doses de 0; 3,5 e 13,5 t/ha; nas sub-subparcelas semearam-se 36 cultivares de milho. As diferenças no rendimento de grãos entre cultivares cultivadas na ausência de calcário, evidenciaram grande variabilidade na tolerância à acidez do solo. Observou-se também grande variação na eficiência de resposta à calagem, indicada pelo coeficiente de regressão das equações lineares entre o rendimento relativo e a percentagem de saturação Al3+ trocável, proporcionado pelas doses de calcário aplicadas. Com base na média dos rendimentos obtidos em ausência de calagem e na média do coeficiente de regressão daquelas equações, as cultivares foram agrupadas em três classes: baixa tolerância à acidez do solo, com alta eficiência de resposta à calagem; alta tolerância à acidez do solo, com baixa eficiência de resposta à calagem; alta tolerância à acidez do solo e alta eficiência de resposta à calagem

    Atividade amilolítica e germinação de sementes de milho submetidas à deficiência de oxigênio.

    Get PDF
    Este trabalho teve como objetivo avaliar os efeitos causados pela deficiência de O2 em sementes de milho na atividade amilolítica e sua influência no vigor das sementes e crescimentodas plântulas

    On the road to per cent accuracy - V. The non-linear power spectrum beyond ΛCDM with massive neutrinos and baryonic feedback

    Get PDF
    In the context of forthcoming galaxy surveys, to ensure unbiased constraints on cosmology and gravity when using non-linear structure information, per cent-level accuracy is required when modelling the power spectrum. This calls for frameworks that can accurately capture the relevant physical effects, while allowing for deviations from Lambda cold dark matter (ΛCDM). Massive neutrino and baryonic physics are two of the most relevant such effects. We present an integration of the halo model reaction frameworks for massive neutrinos and beyond ΛCDM cosmologies. The integrated halo model reaction, combined with a pseudo-power spectrum modelled by HMCode2020 is then compared against N-body simulations that include both massive neutrinos and an f(R) modification to gravity. We find that the framework is 4 per cent accurate down to at least ≈ 3 h Mpc-1 for a modification to gravity of |fR0| ≤ 10-5 and for the total neutrino mass Mν Σmν ≤ 0.15 eV. We also find that the framework is 4 per cent consistent with EuclidEmulator2 as well as the Bacco emulator for most of the considered νwCDM cosmologies down to at least k ≈ 3 h Mpc-1. Finally, we compare against hydrodynamical simulations employing HMCode2020's baryonic feedback modelling on top of the halo model reaction. For νΛCDM cosmologies, we find 2 per cent accuracy for Mν ≤ 0.48 eV down to at least k ≈ 5h Mpc-1. Similar accuracy is found when comparing to νwCDM hydrodynamical simulations with Mν = 0.06 eV. This offers the first non-linear, theoretically general means of accurately including massive neutrinos for beyond-ΛCDM cosmologies, and further suggests that baryonic, massive neutrino, and dark energy physics can be reliably modelled independently

    ATLAS B0 toroid model coil test at CERN

    Get PDF
    The ATLAS superconducting magnet system consists of a Barrel Toroid, two End-Cap Toroids and a Central Solenoid. The Barrel Toroid, with overall dimensions of 20-m diameter by 26-m length, is made of eight individual coils symmetrically assembled around the central axis with a warm structure. The system is presently under construction in industry. In order to verify the construction concepts a model coil B0, a 9-m short version of a single Barrel Toroid coil, was built. Since April 2001, an extensive test program is underway at CERN to characterize the mechanical, thermal, electrical and magnetic properties of the coil. The magnet successfully achieved the 20-kA nominal operating current in July 2001. The test program and the main results are reported. (9 refs)

    On the road to per cent accuracy - V. The non-linear power spectrum beyond Lambda CDM with massive neutrinos and baryonic feedback

    Get PDF
    In the context of forthcoming galaxy surveys, to ensure unbiased constraints on cosmology and gravity when using non-linear structure information, per cent-level accuracy is required when modelling the power spectrum. This calls for frameworks that can accurately capture the relevant physical effects, while allowing for deviations from Lambda cold dark matter (ΛCDM). Massive neutrino and baryonic physics are two of the most relevant such effects. We present an integration of the halo model reaction frameworks for massive neutrinos and beyond ΛCDM cosmologies. The integrated halo model reaction, combined with a pseudo-power spectrum modelled by HMCode2020 is then compared against N-body simulations that include both massive neutrinos and an f(R) modification to gravity. We find that the framework is 4 per cent accurate down to at least k≈3hMpc−1 for a modification to gravity of |fR0| ≤ 10−5 and for the total neutrino mass Mν ≡ ∑mν ≤ 0.15 eV. We also find that the framework is 4 per cent consistent with EuclidEmulator2 as well as the Bacco emulator for most of the considered νwCDM cosmologies down to at least k≈3h Mpc−1. Finally, we compare against hydrodynamical simulations employing HMCode2020’s baryonic feedback modelling on top of the halo model reaction. For νΛCDM cosmologies, we find 2 per cent accuracy for Mν ≤ 0.48 eV down to at least k ≈ 5h Mpc−1. Similar accuracy is found when comparing to νwCDM hydrodynamical simulations with Mν = 0.06 eV. This offers the first non-linear, theoretically general means of accurately including massive neutrinos for beyond-ΛCDM cosmologies, and further suggests that baryonic, massive neutrino, and dark energy physics can be reliably modelled independently

    Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

    Get PDF
    The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal
    corecore