Estudo preliminar da compatibilidade da variedade Thompson Seedless sobre 10 porta-enxertos.

Tendo em vista a grande variação de comportamento da combinação copa x porta-enxerto, para diferentes condições de clima e solo, este trabalho teve como objetivo avaliar o nível de compatibilidade e pegamento na enxertia da cultivar Thompson Seedless sobre 10 tipos de porta-enxertos, visando ampliar a gama de variedades disponíveis, com bons resultados na enxertia de mesa

Rational approximation and arithmetic progressions

A reasonably complete theory of the approximation of an irrational by rational fractions whose numerators and denominators lie in prescribed arithmetic progressions is developed in this paper. Results are both, on the one hand, from a metrical and a non-metrical point of view and, on the other hand, from an asymptotic and also a uniform point of view. The principal novelty is a Khintchine type theorem for uniform approximation in this context. Some applications of this theory are also discussed

Divergência fenotípica entre acessos de uvas de vinho no semi-árido brasileiro.

No manejo das coleções de germoplasma vegetal, a estimativa variabilidade entre acessos proporcionao estabelecimento de estratégias de identificação de parentais de interesse para obtenção de híbridos em programas de melhoramento

Des filets anti insectes pour protéger les cultures maraîchères en Afrique Subsaharienne : une technologie rentable et adaptée aux conditions climatiques

La protection des cultures maraîchères avec des filets anti-insectes en climat tropical au Bénin et au Kenya s'est avérée extrêmement efficace contre les principaux ravageurs tant au stade pépinière qu'en grande culture. Cependant, les filets ne protègent pas toujours suffisamment les cultures contre les insectes piqueurs comme les pucerons et les aleurodes. L'ouverture des filets en milieu de journée peut être une alternative pour conserver l'action des ennemis naturels et réduire l'impact négatif sur le microclimat. L'efficacité des barrières physique et visuelle peut aussi être complétée par une barrière chimique sous la forme d'un composé répulsif imprégné dans le filet. Les petits producteurs qui ont adopté les filets au Bénin et au Kenya ont réduit le nombre d'applications d'insecticide de 70 à 100 % tout en augmentant leur production en quantité et en qualité. L'analyse coût-bénéfice de la technologie a montré que des filets anti-insectes ont multiplié par 3 le taux de rentabilité de la culture de chou par rapport aux pratiques conventionnelles des petits producteurs. Du fait de sa compatibilité avec les méthodes de lutte biologique, cette technologie ouvre une voie prometteuse pour développer une production maraîchère agroécologique. (Résumé d'auteur

Efficient generation of energetic ions in multi-ion plasmas by radio-frequency heating

We describe a new technique for the efficient generation of high-energy ions with electromagnetic ion cyclotron waves in multi-ion plasmas. The discussed ‘three-ion’ scenarios are especially suited for strong wave absorption by a very low number of resonant ions. To observe this effect, the plasma composition has to be properly adjusted, as prescribed by theory. We demonstrate the potential of the method on the world-largest plasma magnetic confinement device, JET (Joint European Torus, Culham, UK), and the high-magnetic-field tokamak Alcator C-Mod (Cambridge, USA). The obtained results demonstrate efficient acceleration of 3He ions to high energies in dedicated hydrogen–deuterium mixtures. Simultaneously, effective plasma heating is observed, as a result of the slowing-down of the fast 3He ions. The developed technique is not only limited to laboratory plasmas, but can also be applied to explain observations of energetic ions in space-plasma environments, in particular, 3He-rich solar flares.This paper is dedicated to the late P. E. M. Vandenplas, founder and first director of LPP-ERM/KMS, in recognition of his lifelong outstanding commitment to fusion research, in particular to ICRH. The support from the JET and Alcator C-Mod Teams is warmly acknowledged. We are grateful to A. Cardinali, C. Castaldo, R. Dumont, J. Eriksson, T. Fülöp, C. Giroud, C. Hellesen, S. Menmuir and M. Schneider for fruitful discussions. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 under grant agreement no. 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. This work was also supported by the US DoE, Office of Science, Office of Fusion Energy Sciences, SciDAC Center for Simulation of Wave Plasma Interactions under DE-FC02-01ER54648 and the User Facility Alcator C-Mod under DE-FC02-99ER54512. The Alcator C-Mod Team author list is reproduced from ref. 12. The JET Contributors author list is reproduced from ref. 33.Peer ReviewedPostprint (author's final draft

Modelling of the effect of ELMs on fuel retention at the bulk W divertor of JET

Effect of ELMs on fuel retention at the bulk W target of JET ITER-Like Wall was studied with multi-scale calculations. Plasma input parameters were taken from ELMy H-mode plasma experiment. The energetic intra-ELM fuel particles get implanted and create near-surface defects up to depths of few tens of nm, which act as the main fuel trapping sites during ELMs. Clustering of implantation-induced vacancies were found to take place. The incoming flux of inter-ELM plasma particles increases the different filling levels of trapped fuel in defects. The temperature increase of the W target during the pulse increases the fuel detrapping rate. The inter-ELM fuel particle flux refills the partially emptied trapping sites and fills new sites. This leads to a competing effect on the retention and release rates of the implanted particles. At high temperatures the main retention appeared in larger vacancy clusters due to increased clustering rate