Beta-diversity, defined as spatial replacement in species composition, is crucial to the understanding of how local communities assemble. These changes can be driven by environmental or geographic factors (such as geographic distance), or a combination of the two. Spiders have been shown to be good indicators of environmental quality. Accordingly, spiders are used in this work as model taxa to establish whether there is a decrease in community similarity that corresponds to geographic distance in the grasslands of the Campos & Malezales ecoregion (Corrientes). Furthermore, the influence of climactic factors and local vegetation heterogeneity (environmental factors) on assemblage composition was evaluated. Finally, this study evaluated whether the differential dispersal capacity of spider families is a factor that influences their community structure at a regional scale. Spiders were collected with a G-Vac from vegetation in six grassland sites in the Campos & Malezales ecoregion that were separated by a minimum of 13 km. With this data, the impact of alpha-diversity and different environmental variables on the beta-diversity of spider communities was analysed. Likewise, the importance of species replacement and nesting on beta-diversity and their contribution to the regional diversity of spider families with different dispersion capacities was evaluated. The regional and site-specific inventories obtained were complete. The similarity between spider communities declined as the geographic distance between sites increased. Environmental variables also influenced community composition; stochastic events and abiotic forces were the principal intervening factors in assembly structure. The differential dispersal capacity of spider groups also influenced community structure at a regional scale. The regional beta-diversity, as well as species replacement, was greater in high and intermediate vagility spiders; while nesting was greater in spiders with low dispersion capacity. Geographic distance, among other factors (climate, and active and passive dispersion capacity), explains assembly structure and the decrease spider community similarity between geographically distant sites. Spiders with the highest dispersal capacity showed greater species replacement. This may be due to the discontinuity (both natural and anthropic) of the grasslands in this ecoregion, which limits the dispersal capacity of these spiders, and their close dependence on microhabitats. The dispersal capacity of the least vagile spiders is limited by geographic distance and biotic factors, such as competition, which could explain the nesting observed between their communities.

ResumoO objetivo da pesquisa foi avaliar a variação de volume dos três constituintes dentinários (Intertubular [I], Peritubular [P] e Lúmen submetidas à tração, o que explicaria a origem da lesão cervical não cariosa [LCNC]. Um modelo 2D "plane strain" representativo da célula unitária microestrutural da dentina, constituído por 1292 elementos triangulares quadráticos, composto pelas fases: I, P e L, foi submetido a aplicações de pressão que geraram tensões médias de tração que variaram entre 7,5 -75 MPa, através do através deles a desmineralização localizada que caracteriza a LCNC. Palavras

To speak about virtual exchange, I can give you some key words which we are going to elaborate for the next 45 minutes: 'terrorist attacks', 'Bataclan', and other such words. I can also speak about the teachers' views, the fact that teachers today need more motivation, social acknowledgement, and prestige. I also mean to speak about digital skills and the myths around them, starting with 'digital natives'; an expression we use so quickly that falls short of our expectations. Virtual exchange is also about mobility.