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Several criteria have been proposed for defining cyberbullying to young people, but no studies have proved their relevance. There are also variations across different countries in the meaning and the definition of this behavior. We systematically investigated the role of five definitional criteria for cyberbullying, in six European countries. These criteria (intentionality, imbalance of power, repetition, anonymity, and public vs. private) were combined through a set of 32 scenarios, covering a range of four types of behaviors (written-verbal, visual, exclusion, and impersonation). For each scenario, participants were asked whether it was cyberbullying or not. A randomized version of the questionnaire was shown to 295 Italian, 610 Spanish, 365 German, 320 Sweden, 336 Estonian, and 331 French adolescents aged 11-17 years. Results from multidimensional scaling across country and type of behavior suggested a clear first dimension characterized by imbalance of power and a clear second dimension characterized by intentionality and, at a lower level, by anonymity. In terms of differences across types of behaviors, descriptive frequencies showed a more ambiguous role for exclusion as a form of cyberbullying, but general support was given to the relevance of the two dimensions across all the types of behavior. In terms of country differences, French participants more often perceived the scenarios as cyberbullying as compared with those in other countries, but general support was found for the relevance of the two dimensions across countries.

Assessing the impact of farmer management of maize landraces in the Central Valleys of Oaxaca, Mexico is crucial to an understanding of maize evolution, as it was first domesticated there. In this paper, we report on the impact of traditional farmer management of maize populations in this region in structuring molecular diversity and on the population dynamics of maize landraces. These populations, from a sample of local landraces cultivated by farmers in six villages, show little among-population differentiation (F st ¼ 0.011). Most surprisingly, there is no isolation by distance and small among-village differentiation (F st ¼ 0.003). For an outbreeding plant such as maize, one would expect populations to fit Hardy-Weinberg equilibrium, but significant homozygote excess (F is ¼ 0.13) was found. This homozygote excess shows remarkable interpopulation and interlocus differences. We show that this pattern is related to variation in the mean anthesis-silking interval as well as to the flowering range or heterogeneity in flowering of a given population. A short anthesis-silking interval and high level of heterogeneity in flowering precocity will favor assortative mating. This leads to a locus-dependent population substructure giving an unusual case of Wahlund effect and inbreeding while high levels of seed exchange among farmers prevent population differentiation at both village and regional levels.

To conserve the long-term selection potential of maize, it is necessary to investigate past and present evolutionary processes that have shaped quantitative trait variation. Understanding the dynamics of quantitative trait evolution is crucial to future crop breeding. We characterized population differentiation of maize landraces from the State of Oaxaca, Mexico for quantitative traits and molecular markers. Q st values were much higher than F st values obtained for molecular markers. While low values of F st (0.011 withinvillage and 0.003 among-villages) suggest that considerable gene flow occurred among the studied populations, high levels of population differentiation for quantitative traits were observed (ie an among-village Q st value of 0.535 for kernel weight). Our results suggest that although quantitative traits appear to be under strong divergent selection, a considerable amount of gene flow occurs among populations. Furthermore, we characterized nonproportional changes in the G matrix structure both within and among villages that are consequences of farmer selection. As a consequence of these differences in the G matrix structure, the response to multivariate selection will be different from one population to another. Large changes in the G matrix structure could indicate that farmers select for genes of major and pleiotropic effect. Farmers' decision and selection strategies have a great impact on phenotypic diversification in maize landraces.

This paper explores social arrangements associated with seed transactions among small-scale maize farmers in the Central Valleys of Oaxaca, Mexico, where no formal seed supply system exists. We test the hypothesis that individual farmers have strong incentives to participate in some form of collective action to ensure their access to seed. Six communities were studied, three of them in detail, using in-depth, semistructured interviews with key informants; focus group discussions; and a tracer study that followed seed flows among farmers. Farmers mostly saved seed and only occasionally acquired seed from outside sources. We found no evidence of a specialized social organization based on collective action to mediate seed flows. Seed transactions are infrequent, bilateral, and ad hoc, although trust is an important component, as it ensures reliable information about the seed is provided. Implications of these findings are discussed, especially for genetic diversity if the current supply system breaks down.

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-The objective of this work was to evaluate the genetic diversity, its organization and the genetic relationships within oil palm (Elaeis oleifera (Kunth) Cortés, from America, and E. guineensis (Jacq.), from Africa) germplasm using Restriction Fragment Length Polymorphism (RFLP) and Amplified Fragment Length Polymorphism (AFLP). In complement to a previous RFLP study on 241 E. oleifera accessions, 38 E. guineensis accessions were analyzed using the same 37 cDNA probes. These accessions covered a large part of the geographical distribution areas of these species in America and Africa. In addition, AFLP analysis was performed on a sub-set of 40 accessions of E. oleifera and 22 of E. guineensis using three pairs of enzyme/primer combinations. Data were subjected to Factorial Analysis of Correspondence (FAC) and cluster analysis, with parameters of genetic diversity being also studied. Results appeared congruent between RFLP and AFLP. In the E. oleifera, AFLP confirmed the strong structure of genetic diversity revealed by RFLP, according to geographical origin of the studied material, with the identification of the same four distinct genetic groups: Brazil, French Guyana/Surinam, Peru, north of Colombia/Central America. Both markers revealed that genetic divergence between the two species is of the same magnitude as that among provenances of E. oleifera. This finding is in discrepancy with the supposed early tertiary separation of the two species. Os resultados obtidos apresentaram grande coerência entre as duas técnicas utilizadas, RFLP e AFLP. Na espécie E. oleifera, a técnica AFLP confirmou a forte estruturação da diversidade genética revelada pela técnica de RFLP, de acordo com a origem geográfica do material estudado e com a identificação dos mesmos quatro grupos genéticos distintos: Brasil, Guiana Francesa/Suriname, Peru e norte da Colômbia/ América Central. Entretanto, ambos os marcadores revelaram que a divergência entre as duas espécies é da mesma magnitude da divergência dentro da espécie americana. Este resultado está em discrepância com uma suposta separação das duas espécies durante a era terciária.Termos para indexação: Elaeis oleifera, Elaeis guineensis, genética de população, palmeiras, recursos genéticos, caracterização molecular.

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