Irreducible pseudo 2-factor isomorphic cubic bipartite graphs

A bipartite graph is {\em pseudo 2--factor isomorphic} if all its 2--factors have the same parity of number of circuits. In \cite{ADJLS} we proved that the only essentially 4--edge-connected pseudo 2--factor isomorphic cubic bipartite graph of girth 4 is $K_{3,3}$, and conjectured \cite[Conjecture 3.6]{ADJLS} that the only essentially 4--edge-connected cubic bipartite graphs are $K_{3,3}$, the Heawood graph and the Pappus graph. There exists a characterization of symmetric configurations $n_3$ %{\bf decide notation and how to use it in the rest of the paper} due to Martinetti (1886) in which all symmetric configurations $n_3$ can be obtained from an infinite set of so called {\em irreducible} configurations \cite{VM}. The list of irreducible configurations has been completed by Boben \cite{B} in terms of their {\em irreducible Levi graphs}. In this paper we characterize irreducible pseudo 2--factor isomorphic cubic bipartite graphs proving that the only pseudo 2--factor isomorphic irreducible Levi graphs are the Heawood and Pappus graphs. Moreover, the obtained characterization allows us to partially prove the above Conjecture

Diagnostics of fruit trees phytoplasmas – the importance of latent infections

In the period 2000-2008 more than 1300 fruit trees from different regions of Slovenia were tested for the quarantine phytoplasmas Apple proliferation (AP), Pear decline (PD), and European stone fruit yellows (ESFY). The majority of samples were collected within systematic official surveys, which was conducted for assessing the presence of these phytoplasma in Slovenia in production and mother plant orchards. Samples were taken from trees with and without expressed symptoms. DNA was extracted from the symptomatic shoots. In addition some roots from asymptomatic trees were sampled for the evaluation of latent infections. The presence of phytoplasmas was analyzed with a nested PCR, RFLP and a real time PCR (Hren et al., 2007). AP, PD and ESFY were confirmed as being present in several areas in Slovenia where fruit trees are cultivated. AP was found not only in apple, but also in stone fruit trees such as cherry, apricot and plum (Mehle et al., 2007). By using highly sensitive diagnostic methods, such as real time PCR, some latent infections were detected and they were confirmed next year also by less sensitive methods.Keywords: Phytoplasma, AP, PD, ESFY, latent infection, fruit tree

Testing practices in the 21st century: developments and European psychologists' opinions

The main goal of the European Federation of Psychologists’Associations (EFPA) Standing Committee on Tests and Testing (SCTT) is the improvement of testing practices in European countries. In order to reach this goal, the SCTT carries out various actions and projects, some of which are described in this paper. To better inform its work, it decided to survey the opinions of professional psychologists on testing practices. A questionnaire of 33 items was administered to a sample of 12,606 professional psychologists from 17 European countries. The questionnaire was based on, but not identical to, one used in 2000. The new data show that the positive attitude of the respondents toward the use of tests that was obtained in 2000 has increased in most countries, with a high percentage of the surveyed psychologists using tests regularly. Five main dimensions explained 43% of the total item variance. The dimensions involve items relating to: Concern over incorrect test use, regulations on tests and testing, Internet testing, appreciation of tests, and knowledge and training relating to tests and test use. Important differences between countries were found on these five dimensions. Differences were found according to gender for four of the five dimensions and in relation to field of specialization for all five dimensions. The most commonly used tests are the classic psychometric tests of intelligence and personality: WISC, WAIS, MMPI, RAVEN, 16PF, NEO-PI-R, BDI, SCL-90. Finally, some future perspectives are discussed. (PsycINFO Database Record (c) 2013 APA, all rights reserved