Sustained Antarctic Research: A 21st Century Imperative

The view from the south is, more than ever, dominated by ominous signs of change. Antarctica and the Southern Ocean are intrinsic to the Earth system, and their evolution is intertwined with and influences the course of the Anthropocene. In turn, changes in the Antarctic affect and presage humanity's future. Growing understanding is countering popular beliefs that Antarctica is pristine, stable, isolated, and reliably frozen. An aspirational roadmap for Antarctic science has facilitated research since 2014. A renewed commitment to gathering further knowledge will quicken the pace of understanding of Earth systems and beyond. Progress is already evident, such as addressing uncertainties in the causes and pace of ice loss and global sea-level rise. However, much remains to be learned. As an iconic global “commons,” the rapidity of Antarctic change will provoke further political action. Antarctic research is more vital than ever to a sustainable future for this One Earth

Acoustic impedance and basal shear stress beneath four Antarctic ice streams

The acoustic impedance of the subglacial material beneath 7.2 km profiles on four ice streams in Antarctica has been measured using a seismic technique. The ice streams span a wide range, of dynamic conditions with flow rates of 35-464 in a(-1). The acoustic impedance indicates that poorly lithified or dilated sedimentary material is ubiquitous beneath these ice streams. Mean acoustic impedance across each profile correlates well with basal shear stress and the slipperiness of the bed, indicating that acoustic impedance is a good diagnostic not only for the porosity of the subglacial material, but also for its dynamic state (deforming or non-deforming). Beneath two of the ice streams, lodged (non-deforming) and dilated (deforming) sediment coexist but their distribution is not obviously controlled by basal topography or ice thickness. Their distribution may be controlled by complex material properties or the deformation history. Beneath Rutford Ice Stream, lodged and dilated sediment coexist and are distributed in broad bands several kilometres wide, while on Talutis Inlet there is considerable variability over much shorter distances; this may reflect differences in the mechanism of drainage beneath the ice streams. The material beneath the slow-moving Carlson Inlet is probably lodged but unlithified sediment; this is consistent with the hypothesis that Carlson Inlet was once a fast-flowing ice stream but is now in a stagnant phase, which could possibly be revived by raised basal water content. The entire bed beneath fast-flowing Evans Ice Stream is dilated sediment

Complete atrioventricular canal in a dog

Boron (B) has many beneficial functions in biological, metabolic and physiological processes for plants and animals. It plays a vital role in maintaining animal health and preventing nutritional disorders. Boron deficiency has been correlated with low immune function and high incidence of osteoporosis which increases mortality risk. Extraordinary boron level causes cell damage and toxicity in human and different animal species. In the past few years, attention has been paid to clear the pleiotropic effects of boron including activating of immune response, antioxidant detoxification activities, affecting bone metabolism, enhancing animal performance and modulating various body systems. Furthermore, the role of boron as anti-heat stress agent has been identified in plants and suggested in animals. Liver metabolism also shows significant alterations in dairy cows in response to the dietary supplementation of boron. Likewise, adding boron to animal feed enhances bone density, wound healing and embryonic development. Additionally, boron has a potential impact on the metabolism of numerous minerals and enzymes. In view of the information about boron benefits, high or low level boron merits the concern. As well, researches are required to do more in-depth investigations on boron influences, and to adjust its requirements in different animal specie