A major obstacle in understanding the evolution of Cenozoic climate has been the lack of well dated terrestrial evidence from high-latitude, glaciated regions. Here, we report the discovery of exceptionally well preserved fossils of lacustrine and terrestrial organisms from the McMurdo Dry Valleys sector of the Transantarctic Mountains for which we have established a precise radiometric chronology. The fossils, which include diatoms, palynomorphs, mosses, ostracodes, and insects, represent the last vestige of a tundra community that inhabited the mountains before stepped cooling that first brought a full polar climate to Antarctica. Paleoecological analyses, 40 Ar/ 39 Ar analyses of associated ash fall, and climate inferences from glaciological modeling together suggest that mean summer temperatures in the region cooled by at least 8°C between 14.07 ؎ 0.05 Ma and 13.85 ؎ 0.03 Ma. These results provide novel constraints for the timing and amplitude of middle-Miocene cooling in Antarctica and reveal the ecological legacy of this global climate transition.climate change ͉ tundra biota ͉ Dry Valleys ͉ diatoms ͉ ostracods
Among extant land plants, mosses are the second most speciose group after the angiosperms, and, together with liverworts, contribute a significant fraction of the species diversity in many environments, including those (desert, high montane, and high latitude) where vascular plants are sparse or absent. Their physical structure and physiological attributes (for example, desiccation resistance/drought tolerance, nutrient-capturing abilities) allow them to play major roles in many of the world's ecosystems, affecting water and mineral fluxes, controlling surface run-off and erosion, and providing food and habitat for a wide range of organisms including other plants, fungi, bacteria, invertebrates, birds, and mammals. They are a remnant of one of the earliest branching events in the radiation of the plants on land, and systematic studies of mosses should consequently provide substantial information relevant to the understanding of land plant origins, evolution, and diversity. Although
Dairy products are heated both during processing and by consumers during food preparation; consumers place a high level of importance on flavour when assessing product acceptability. Of particular importance to the flavour of heated dairy products is the highly complex network of Maillard reactions. Much focus has been placed on the undesirable flavours generated through the Maillard reaction and how to minimise the formation of these flavours. However, beneficial flavours can also be formed by the Maillard reaction; dairy products, such as ghee, are formed by heating and are characterised by the unique flavour generated by this chemistry. This review looks at the Maillard reaction as a source of beneficial flavours for cooked dairy products and the application of models to the study of flavour formation in food systems. Models are typically used to study complex reactions in a simplified way; however, they are not always applicable to food systems.
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