Evaluation of Medipix2 detector for recording electron diffraction data in low dose conditions

Biophysical Structural Chemistr

Plant and fungal use in Tusheti, Khevsureti, and Pshavi, Sakartvelo (Republic of Georgia), Caucasus

In this study, we documented traditional plant use in Tusheti, Khevsureti, and Pshavi and hypothesized that (i) plant use knowledge in general would be higher in isolated high elevation communities, and that (ii) use of home gardens would be much more restricted to lower elevation settings. Fieldwork was conducted in Khevsureti, Pshavi, and Tusheti. Interviews using semi-structured questionnaires were conducted with 74 participants. In the present study, we encountered 317 plant species belonging to 203 genera of 80 families being used in the research region. Of these, 197 species were exclusively wild-harvested, 73 were grown in homegardens, and 47 were both grown in gardens and sourced in the wild. The ordinations in plant-space and in use-space were significantly fit by elevation of informant community, and community itself. Age and gender did not significantly fit the distribution of informants across either plant-space or use-space, respectively. Number of use-reports was highest across all communities in the food and medicinal use-categories, and informant consensus. Species with especially high use-diversity (UD) tended to be woody species although. Species with high use-value (UV) were mostly managed/domesticated species from home orchards, gardens, or farms. Plant species, and uses, found in our study, showed clear relations to the wider Eurasian cultural complex. The species number found was, however, far higher than in any published study from either the region or the wiser Mediterranean and Eurasia. The maintenance of home gardens in Georgia serves as socio-ecological memory. While the great variety of plant species used in the Georgian Caucasus might provide a reservoir for food security climate change is starting to affect both natural floristic diversity and gardens both in the Caucasus as well as continent wide

Electric field induced order reconstruction in a nematic cell

We have experimentally observed the biaxial switching between two topologically distinct textures of a nematic liquid crystal cell submitted to a strong electric field. The effect is deduced from optical and electrical measurements across the cell. Above a static threshold, a bulk order reconstruction is observed, where the final nematic orientation in the centre becomes perpendicular to its initial one, inducing a total π change of orientation across the cell. Using short electric field pulses, a higher dynamical threshold is observed. These experiments are explained by a Landau-de Gennes-Khalatnikov model. The threshold implies the local exchange of two eigenvalues of the nematic order tensor through intermediate biaxial states. The onset of the effect in a thin splay-bend wall decreases the static threshold by almost an order of magnitude. The model explains reasonably well the static and dynamic measurements within the present description of nematic biaxiality