Araujo E.R.,Universida Of Brasilia |
Pereira R.C.,Universida Of Brasilia |
Ferreira M.A.S.V.,Universida Of Brasilia |
Cafe-Filho A.C.,Universida Of Brasilia |
And 2 more authors.
Acta Horticulturae | Year: 2011
Bacterial spot is a major problem for the Brazilian processing tomato industry. The disease is caused by four different species of the genus Xanthomonas. The objectives of this study were to evaluate the effect of temperature on pathogenicity components of bacterial spot caused by each species separately and to assess the competitiveness between X. perforans and X. gardneri in planta. Representative strains of each species were inoculated separately on susceptible tomato plants at 20, 25 and 30°C and the ensuing disease was measured by the percentage of diseased leaf area. Assessment of competitiveness was carried out under greenhouse conditions, by single and combined inoculations of X. perforans and X. gardneri. Colonies were recovered from the inoculations and the frequency of each species was determined. The interactions of temperature and bacterial species for pathogenicity components were significant. At 20°C, X. gardneri induced the highest percentage of diseased leaf area, whereas at 30°C, X. perforans was the most aggressive. Incubation period varied from 5 to 8 days according to the temperature. In the competitiveness assay, only X. perforans was recovered in half of the combined inoculations. Results indicate that temperature has an important role in determining which species will be prevalent in a particular region, especially concerning X. perforans and X. gardneri, since each of these species seemed to be more adaptable to one thermal zone.
Rodrigues M.,University of Brasilia |
Castello Branco I.,University of Brasilia |
Shimioshi J.,Universida Of Brasilia |
Rodrigues E.,Universida Of Brasilia |
And 2 more authors.
Work | Year: 2012
This paper presents an analysis of cognitive-ergonomic aspects of e-learning courses, offered by an organism from Brazilian Public Administration. The Cognitive Ergonomic studies conductive and cognitive aspects concerning to the relation between human, physics elements and social elements of the work space. From that usability aspects were evaluated by these points: i) visualization; ii) text comprehension lecture; iii) memory; iv) interface; v) instructional design; and vi) attention and learning. That survey is characterized as having been applied using the following techniques: (1) bibliographic survey, (2) field survey and (3) analysis of the documents. It was chosen the semi-structured questionnaire as the main method of data collection. About the interacting with artifacts, the interface of the courses is classified as direct engagement, because it allows the user to get the feeling that acts directly on the objects. Although the courses are well-structured they have flaws that will be discussed below. Even with these problems, the courses have a good degree of usability. © 2012 - IOS Press and the authors. All rights reserved.