Suchergebnisse

The olive quick decline syndrome (OQDS) is a novel disease recently emerged in southern Italy and currently threating the Mediterranean olive-growing area. The disease was found to be associated with infections caused by the exotic bacterium X. fastidiosa, well known in the Americas as the causal agent of severe diseases of important crops, i.e. grapevine and citrus. In these species, looking for resistance is regarded as one of the most promising long term control strategies. In olives, cultivars displaying differential phenotypes have been observed in the field, with symptoms ranging from virtually no decline and limited desiccation in Leccino and FS-17® to severe decline and death cvs Cellina di Nardo and Ogliarola Salentina. However, the large variability of olive genetic resources, including both cultivated and wild olives remains to be explored. Several experiments are currently ongoing aiming at detecting new sources of resistance in plant materials representative of the genetic and geographical variability of the species, including commercial cultivars, genotypes from other Olea europaea subspecies, and selections from breeding programs. Identified resistant sources could serve as parental for breeding programs, as currently underway for other vascular diseases such as Verticillium wilt. The status and challenges of the currently ongoing activities will be presented. ; Acknowledgment This work has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement N. 727987 "Xylella fastidiosa Active Containment Through a multidisciplinary-Oriented Research Strategy XF-ACTORS".

Polyimide co-polymers have been prepared based on different diamines as co-monomers: a diamine without CN groups and a novel synthesized diamine with two CN groups prepared by polycondensation reaction followed by thermal cyclodehydration. Dielectric spectroscopy measurements were performed and the dielectric complex function, ac conductivity and electric modulus of the co-polymers were investigated as a function of CN group content in the frequency range from 0.1 Hz to 107 Hz at temperatures from 25 to 260 °C. For all samples and temperatures above 150ºC, the dielectric constant increases with increasing temperature due to increaseing conductivity. The α-relaxation is just detected for the sample without CN groups, being this relaxation overlapped by the electrical conductivity contributions in the remaining samples. For the copolymer samples and the polymer with CN groups an important Maxwell-Wagner-Sillars contribution is detected. The mechanisms responsible for the dielectric relaxation, conduction process and electric modulus response have been discussed as a function of the CN groups content present in the samples. ; This work was supported by FEDER through the COMPETE Program and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Project PESTC/FIS/UI607/2011 and grants SFRH/BD/ 62507/2009 (A.C.L.) SFRH/BD/68499/2010 (C.M.C.). The authors also thank funding from "Matepro – Optimizing Materials and Processes", ref. NORTE-07-0124-FEDER-000037", co-funded by the "Programa Operacional Regional do Norte" (ON.2 – O Novo Norte), under the "Quadro de Referência Estratégico Nacional" (QREN), through the "Fundo Europeu de Desenvolvimento Regional" (FEDER). RSS acknowledge the support of the Spanish Ministry of Economy and Competitiveness through the project MAT2012-38359-C03-01 (including the FEDER financial support). Authors also thank the Basque Country Government for financial support (ACTIMAT project, ETORTEK Program, IE13-380, and Ayudas para Grupos de Investigación ...