Australian National University

About: Australian National University is a education organization based out in Canberra, Australian Capital Territory, Australia. It is known for research contribution in the topics: Population & Galaxy. The organization has 34419 authors who have published 109261 publications receiving 4315448 citations. The organization is also known as: The Australian National University & ANU.

Evolution of halophytes: multiple origins of salt tolerance in land plants

Abstract: The evolution of salt tolerance is interesting for several reasons. First, since salt-tolerant plants (halophytes) employ several different mechanisms to deal with salt, the evolution of salt tolerance represents a fascinating case study in the evolution of a complex trait. Second, the diversity of mechanisms employed by halophytes, based on processes common to all plants, sheds light on the way that a plant’s physiology can become adapted to deal with extreme conditions. Third, as the amount of salt-affected land increases around the globe, understanding the origins of the diversity of halophytes should provide a basis for the use of novel species in bioremediation and conservation. In this review we pose the question, how many times has salt tolerance evolved since the emergence of the land plants some 450–470 million years ago? We summarise the physiological mechanisms underlying salt-tolerance and provide an overview of the number and diversity of salt-tolerant terrestrial angiosperms (defined as plants that survive to complete their life cycle in at least 200 mM salt). We consider the evolution of halophytes using information from fossils and phylogenies. Finally, we discuss the potential for halophytes to contribute to agriculture and land management and ask why, when there are naturally occurring halophytes, it is proving to be difficult to breed salt-tolerant crops.

Climate Change and Human Health

Abstract: The article “Apocalypse not” by Gary Taubes (News & Comment, 7 Nov., [p. 1004][1]) addresses the issue of fundamental differences of opinion among health scientists about the impact of climate on human health. While we acknowledge that there are strong differences in opinion about the potential consequences of future climate change on disease incidence and distribution, we share common concerns; we wish to emphasize that despite any differences, there are many areas where we agree. The key questions behind the climate/health research agendas are, How will climate change alter health risks, to what extent will risks be altered, and what can be done to mitigate any potential increase in health risks? At issue is not which is more important, climate factors or improved health measures; rather, it is important to assess how health risks might change in both industrialized and more vulnerable developing countries. The complexity of this public health issue entails far more uncertainty than many health hazards with which we are familiar. Impacts may occur indirectly through simultaneous disturbances of other sectors, including water supply, food production, or habitat. Thus far, scientists have found great difficult in communicating this extra level of uncertainty. We agree on the need to improve understanding of the complex relationships between climatic conditions and disease transmission dynamics. We also agree that disease incidence is influenced by multiple factors (none of us will argue that climate is the only or the most important factor). Well-designed research studies must be conducted to gain a better understanding of how these multiple factors relate to each other and how all might be influenced by climate. Identifying risk factors that influence disease transmission is a key to public health planning, and as more data from climate/health research studies become available, the influence of weather will be better understood. We recognize that extreme weather events such as those that may accompany this year's El Nino place an extra burden on sanitation and general public health systems. The early regional forecasts obtained from El Nino exemplify important new predictive capabilities that public health officials can use in their public health planning. Interdisciplinary research and interagency cooperation can go far toward improving the health risk assessment associated with climate change. Ecology-based research and monitoring combined with advances in climate forecasting will enhance our understanding of complex environmental health hazards and may provide the public with early warning systems that allow timely public health interventions. The signatories of this letter agree that public health is of great importance and that public health infrastructure and services must be improved worldwide. We recognize that environmental and socioeconomic conditions underpin health status; effective and sustainable public health prevention will ultimately require improvement in these underlying conditions. It is important to realize, however, that the projected climate change may have a profound influence on an aspects of human ecology, and we strongly recommend that research be supported to allow development of effective prevention strategies that will help mitigate its effect on public health. [1]: /lookup/doi/10.1126/science.278.5340.1004

Flavonoids: New Roles for Old Molecules

Abstract: Flavonoids are ubiquitous in the plant kingdom and have many diverse functions including defense, UV protection, auxin transport inhibition, allelopathy, and flower coloring. Interestingly, these compounds also have considerable biological activity in plant, animal and bacterial systems - such broad activity is accomplished by few compounds. Yet, for all the research over the last three decades, many of the cellular targets of these secondary metabolites are unknown. The many mutants available in model plant species such as Arabidopsis thaliana and Medicago truncatula are enabling the intricacies of the physiology of these compounds to be deduced. In the present review, we cover recent advances in flavonoid research, discuss deficiencies in our understanding of the physiological processes, and suggest approaches to identify the cellular targets of flavonoids.

Evaluation of theoretical conversion coefficients using BrIcc

Abstract: A new internal conversion coefficient database, BrIcc has been developed which integrates a number of tabulations on internal conversion electron (ICC) and electron–positron pair conversion coefficients (IPC), as well as Ω ( E 0 ) electronic factors. A critical review of general formulae and procedures to evaluate theoretical ICC and IPC values are presented, including the treatment of uncertainties in transition energy and mixing ratio in accordance with the Evaluated Nuclear Structure Data File. The default ICC table, based on the Dirac–Fock calculations using the so called “Frozen Orbital” approximation, takes into account the effect of atomic vacancies created in the conversion process. The table has been calculated for all atomic shells and to cover transition energies of 1–6000 keV and atomic numbers of Z = 5 –110. The software tools presented here are well suited for basic nuclear structure research and for a range of applications.

wsclean: an implementation of a fast, generic wide-field imager for radio astronomy

Abstract: Astronomical wide-field imaging of interferometric radio data is computationally expensive, especially for the large data volumes created by modern non-coplanar many-element arrays. We present a new wide-field interferometric imager that uses the w-stacking algorithm and can make use of the w-snapshot algorithm. The performance dependences of CASA's w-projection and our new imager are analysed and analytical functions are derived that describe the required computing cost for both imagers. On data from the Murchison Widefield Array, we find our new method to be an order of magnitude faster than w-projection, as well as being capable of full-sky imaging at full resolution and with correct polarization correction. We predict the computing costs for several other arrays and estimate that our imager is a factor of 2-12 faster, depending on the array configuration. We estimate the computing cost for imaging the lowfrequency Square Kilometre Array observations to be 60 PetaFLOPS with current techniques. We find that combining w-stacking with the w-snapshot algorithm does not significantly improve computing requirements over pure w-stacking. The source code of our new imager is publicly released.