Meddelelser

Intet resum

Meddelelser

Intet resum

Developing a Glossary of People-Focused Terms Related to Rangelands and Grasslands

Excellent glossaries on rangelands and grasslands have been developed by the Society for Range Management (SRM), the International Grassland Congress (IGC) and the International Rangeland Congress (IRC). However, these are largely confined to biophysical and technical terminology and contain very few concepts referring to social, institutional and policy aspects of using rangelands and grasslands. After the 10th IRC in Saskatoon, Canada, in 2016, an informal group started to develop a glossary of such “people-focused” terms. The short and non-academic definitions are meant to improve communication and understanding by users/practitioners in rangeland and grassland management, policymakers, teachers, students, journalists and the general public. The glossary focuses on terms in common international use in rangeland management and includes terminology referring to rangelands/grasslands users (e.g. pastoralists, agropastoralists, hunters and gatherers) and to how they organise the use and management of rangeland resources (e.g. common property rights, resource access rights, herding contracts, transhumance and other forms of mobility). More general terms in social sciences are not included, as the debates about their meanings are well covered in the conventional social science literature. Thus far, the glossary is in English only. It is hoped that people working on rangelands and pastoralism in other countries will translate it into other languages and adapt it with area- and language-specific terminology. The definitions in the glossary are intended to fill an existing gap relatively quickly. Previous experience of the SRM, IRC and IGC showed that developing a comprehensive glossary takes several years. The current version of the glossary will doubtless be revised when a more systematic effort is made to define socio-institutional terms related to rangelands and grasslands. In any case, further revisions will be made as concepts evolve and new ones arise, as was the case with the technical glossaries of the SRM, IGC and IRC

Dehydrins in maritime pine (Pinus pinaster) and their expression related to drought stress response

Maritime pine (Pinus pinaster) is an important commercial species throughout its Atlantic distribution. With the anticipated increase in desiccation of its habitat as a result of climate change, the selection of genotypes with increased survival and growth capability under these conditions for breeding programs is of great interest for this species. We aimed to study the response to a realistic drought stress under controlled conditions, looked for a method to measure dehydration resistance, and analyzed dehydrin expression in drought-resistant and drought-sensitive clones from different ecotypes. We report here the sequence characteristics and the expression patterns of five dehydrins from P. pinaster, along with the physiological characterization of drought stress responses in different genotypes (clonally replicated plants), originating from a broad geographical distribution across France and Spain (provenances). In total, we distinguished five different dehydrin genes in silico, grouped into two types—K2 and SKn. Three of the dehydrin genes had several sequence variants, differing by multiple or single amino acid substitutions. Only two of the dehydrins (PpinDhn3 and PpinDhn4) showed an increase in transcription with increased drought stress which was dependent on provenance and genotype, suggesting their involvement in drought resistance. The other dehydrins showed decreased expression trends with increased severity of the drought stress. The lack of close association between the drought stress and expression patterns of these dehydrin genes suggest that they could have other functions and not be involved in drought resistance. Our results suggest large differences in function between different dehydrin genes

Temperature dependence of binary and ternary recombination of H3+ ions with electron

We study binary and the recently discovered process of ternary He-assisted recombination of H3+ ions with electrons in a low temperature afterglow plasma. The experiments are carried out over a broad range of pressures and temperatures of an afterglow plasma in a helium buffer gas. Binary and He-assisted ternary recombination are observed and the corresponding recombination rate coefficients are extracted for temperatures from 77 K to 330 K. We describe the observed ternary recombination as a two-step mechanism: First, a rotationally-excited long-lived neutral molecule H3* is formed in electron-H3+ collisions. Second, the H3* molecule collides with a helium atom that leads to the formation of a very long-lived Rydberg state with high orbital momentum. We present calculations of the lifetimes of H3* and of the ternary recombination rate coefficients for para and ortho-H3+. The calculations show a large difference between the ternary recombination rate coefficients of ortho- and para-H3+ at temperatures below 300 K. The measured binary and ternary rate coefficients are in reasonable agreement with the calculated values.Comment: 15 page