Eruption and propagation of twisted flux ropes from the base of the solar corona to 1 au

Interplanetary Coronal Mass Ejections (ICMEs) originate from the eruption of complex magnetic structures occurring in our star's atmosphere. Determining the general properties of ICMEs and the physical processes at the heart of their interactions with the solar wind is a hard task, in particular using only unidimensional in situ profiles. Thus, these phenomena are still not well understood. In this study we simulate the propagation of a set of flux ropes in order to understand some of the physical processes occurring during the propagation of an ICME such as their growth or their rotation. We present simulations of the propagation of a set of flux ropes in a simplified solar wind. We consider different magnetic field strengths and sizes at the initiation of the eruption, and characterize their influence on the properties of the flux ropes during their propagation. We use the 3D MHD module of the PLUTO code on an Adaptive Mesh Refinement grid. The evolution of the magnetic field of the flux rope during the propagation matches evolution law deduced from in situ observations. We also simulate in situ profiles that spacecraft would have measured at the Earth, and we compare with the results of statistical studies. We find a good match between simulated in situ profiles and typical profiles obtained in these studies. During their propagation, flux ropes interact with the magnetic field of the wind but still show realistic signatures of ICMEs when analyzed with synthetic satellite crossings. We also show that flux ropes with different shapes and orientations can lead to similar unidimensional crossings. This warrants some care when extracting magnetic topology of ICMEs using unidimensional crossings.Comment: Accepted for publication A&A. 14 pages, 9 figures, 3 table

Injection of photoelectrons into dense argon gas

The injection of photoelectrons in a gaseous or liquid sample is a widespread technique to produce a cold plasma in a weakly--ionized system in order to study the transport properties of electrons in a dense gas or liquid. We report here the experimental results of photoelectron injection into dense argon gas at the temperatureT=142.6 K as a function of the externally applied electric field and gas density. We show that the experimental data can be interpreted in terms of the so called Young-Bradbury model only if multiple scattering effects due to the dense environment are taken into account when computing the scattering properties and the energetics of the electrons.Comment: 18 pages, 10 figures, figure nr. 10 has been redrawn, to be submitted to Plasma Sources Science and Technolog

Implementação de diagnóstico por PCR para Fusarium oxysporum f. sp. cubense (raça 4).

O mal-do-panamá é um dos principais problemas fitossanitários da bananeira, causado pelo Fusarium oxysporum f. sp. cubense. A única alternativa eficiente para o controle da doença tem sido a utilização de variedades resistentes, o que nem sempre é possível. O surgimento de novas raças é preocupação constante

Caracterização de isolados de Fusarium oxysporum f. sp. Cubense por marcadores SSR e compatibilidade vegetativa.

O mal-do-Panamá, causado pelo fungo Fusarium oxysporum f. sp. cubense (Foc), é uma das doenças mais destrutivas da bananeira. A medida de controle mais efetiva é o uso de variedades resistentes. O surgimento de novas raças é preocupação constante e fator desafiador para os programas de melhoramento visando resistência à doença

MANAGEMENT OF A MAIN CITRUS PEST BLACK PARLATORIA SCALE PARLATORIA ZIZIPHI (LUCAS) (HEMIPTERA: DIASPIDIDAE) IN THE MEDITERRANEAN BASIN

The scale of black parlatoria, Parlatoria ziziphi (Lucas) (Hemiptera: Diaspididae), causes considerable damage to citrus fruits in the Mediterranean basin. For well managed this pest, we carried out a thorough ecological and behavioral study on the preference of localization and fixation of this pest on the citrus tree throughout the year for two years in six different citrus orchards to know: the lemon, the clementinier and the orange variety Thomson and washington in Tizi Ouzou, sub-humid region of the Mediterranean, in the North of Algeria. This new information on the biology and behavior of P. ziziphi could be applied to the definition of a better pest management strategy and to improvement of sampling methodology for monitoring this devastating pest by the good recognition of its place of infestations

On the Absorption of X-rays in the Interstellar Medium

We present an improved model for the absorption of X-rays in the ISM intended for use with data from future X-ray missions with larger effective areas and increased energy resolution such as Chandra and XMM, in the energy range above 100eV. Compared to previous work, our formalism includes recent updates to the photoionization cross section and revised abundances of the interstellar medium, as well as a treatment of interstellar grains and the H2molecule. We review the theoretical and observational motivations behind these updates and provide a subroutine for the X-ray spectral analysis program XSPEC that incorporates our model.Comment: ApJ, in press, for associated software see http://astro.uni-tuebingen.de/nh

Tecnologia de mudas enxertadas de maracujazeiro azedo para controle de doenças causadas por fusarium spp. no Mato Grosso - a experiência da Coopernova.

Entre as doenças mais sérias do maracujazeiro no Mato Grosso, merecem destaque a murcha e a podridão-do-pé causadas por Fusarium oxysporum f. sp. passiflorae e Fusarium solani, respectivamente. Até o momento não existem cultivares resistentes nem controle químico satisfatório para estas doenças. Por esse motivo, não se recomenda o cultivo do maracujazeiro em áreas com alta incidência destas doenças. A ocorrência destas doenças faz com que muitos produtores sintam-se desestimulados com a cultura do maracujazeiro, considerando que as plantas morrem no início do seu período produtivo