999 resultados para Plant hormone


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Since the publication of Hobsbawm and Rudé's Captain Swing our understanding of the role(s) of covert protests in Hanoverian rural England has advanced considerably. Whilst we now know much about the dramatic practices of incendiarism and animal maiming and the voices of resistance in seemingly straightforward acquisitive acts, one major gap remains. Despite the fact that almost thirty years have passed since E. P. Thompson brought to our attention that under the notorious ‘Black Act’ the malicious cutting of trees was a capital offence, no subsequent research has been published. This paper seeks to address this major lacuna by systematically analysing the practices and patterns of malicious attacks on plants (‘plant maiming’) in the context of late eighteenth- and early nineteenth-century southern England. It is shown that not only did plant maiming take many different forms, attacking every conceivable type of flora, but also that it was universally understood and practised. In some communities plant maiming was the protestors' weapon of choice. As a social practice it therefore embodied wider community beliefs regarding the defence of plebeian livelihoods and identities.

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Plant-parasitic nematodes are major agricultural pests worldwide and novel approaches to control them are sorely needed. We report the draft genome sequence of the root-knot nematode Meloidogyne incognita, a biotrophic parasite of many crops, including tomato, cotton and coffee. Most of the assembled sequence of this asexually reproducing nematode, totaling 86 Mb, exists in pairs of homologous but divergent segments. This suggests that ancient allelic regions in M. incognita are evolving toward effective haploidy, permitting new mechanisms of adaptation. The number and diversity of plant cell wall-degrading enzymes in M. incognita is unprecedented in any animal for which a genome sequence is available, and may derive from multiple horizontal gene transfers from bacterial sources. Our results provide insights into the adaptations required by metazoans to successfully parasitize immunocompetent plants, and open the way for discovering new antiparasitic strategies.

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A constrained non-linear, physical model-based, predictive control (NPMPC) strategy is developed for improved plant-wide control of a thermal power plant. The strategy makes use of successive linearisation and recursive state estimation using extended Kalman filtering to obtain a linear state-space model. The linear model and a quadratic programming routine are used to design a constrained long-range predictive controller One special feature is the careful selection of a specific set of plant model parameters for online estimation, to account for time-varying system characteristics resulting from major system disturbances and ageing. These parameters act as nonstationary stochastic states and help to provide sufficient degrees-of-freedom to obtain unbiased estimates of controlled outputs. A 14th order non-linear plant model, simulating the dominant characteristics of a 200 MW oil-fired pou er plant has been used to test the NPMPC algorithm. The control strategy gives impressive simulation results, during large system disturbances and extremely high rate of load changes, right across the operating range. These results compare favourably to those obtained with the state-space GPC method designed under similar conditions.