230 research outputs found

    Effect of Mesotrione and Nicosulfuron Mixtures With or Without Adjuvants

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    ABSTRACT: In Field experiments, a logarithmic sprayer was used to screen the efficacy of 28.5% mixture of nicosulfuron and mesotrione, and the herbicides applied separately. Three adjuvants were also used to assess how they affected the potency of the mixture. The objectives were to test whether a mixture was enhancing or detracting the effect relative to ADM (Additive Dose Model). The test plants were canola and barley. The 28.5% nicosulfuron mixture was acting antagonistic, irrespective of plant species. The antagonistic effect of the nicosulfuron mixture decreased the more developed the plants became; for barley, it almost disappeared 40 days after treatment. For both canola and barley, one adjuvant stood out as being highly effective in decreasing ED50 of the mixture. Antagonism was not alarmingly high, which is found for many herbicides. Results are discussed in relation to the practice of testing mixtures in the literature and the requirements for getting mixture patents

    Rotação de culturas como sinergismo entre espécies para aumento da produtividade: aspectos teóricos e conceituais

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    «A rotação de culturas é uma prática agrícola de origem milenar e, em várias civilizações da antiguidade, objetivava, principalmente, aumentar a diversidade de produtos colhidos, quando comparado à monocultura [...] continuamente. A rotação de culturas normalmente beneficia a espécie cultivada imediatamente na sequência a um cultivo favorável, como é o caso dos cereais cultivados posteriormente às plantas leguminosas [...]. Adicionalmente, diversos outros benefícios da rotação de culturas também se observam em longo prazo e alguns destes serão abordados nos Capítulos 6 e 7»

    Active Brownian Particles. From Individual to Collective Stochastic Dynamics

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    We review theoretical models of individual motility as well as collective dynamics and pattern formation of active particles. We focus on simple models of active dynamics with a particular emphasis on nonlinear and stochastic dynamics of such self-propelled entities in the framework of statistical mechanics. Examples of such active units in complex physico-chemical and biological systems are chemically powered nano-rods, localized patterns in reaction-diffusion system, motile cells or macroscopic animals. Based on the description of individual motion of point-like active particles by stochastic differential equations, we discuss different velocity-dependent friction functions, the impact of various types of fluctuations and calculate characteristic observables such as stationary velocity distributions or diffusion coefficients. Finally, we consider not only the free and confined individual active dynamics but also different types of interaction between active particles. The resulting collective dynamical behavior of large assemblies and aggregates of active units is discussed and an overview over some recent results on spatiotemporal pattern formation in such systems is given.Comment: 161 pages, Review, Eur Phys J Special-Topics, accepte

    Operation and performance of the ATLAS semiconductor tracker

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    The semiconductor tracker is a silicon microstrip detector forming part of the inner tracking system of the ATLAS experiment at the LHC. The operation and performance of the semiconductor tracker during the first years of LHC running are described. More than 99% of the detector modules were operational during this period, with an average intrinsic hit efficiency of (99.74±0.04)%. The evolution of the noise occupancy is discussed, and measurements of the Lorentz angle, δ-ray production and energy loss presented. The alignment of the detector is found to be stable at the few-micron level over long periods of time. Radiation damage measurements, which include the evolution of detector leakage currents, are found to be consistent with predictions and are used in the verification of radiation background simulations
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