National University of Río Negro

About: National University of Río Negro is a education organization based out in Viedma, Argentina. It is known for research contribution in the topics: Population & Cretaceous. The organization has 606 authors who have published 1181 publications receiving 15230 citations. The organization is also known as: UNRN.

Intriguing detection of $^{12}$CO molecular emission in a classical Be star

Abstract: In the group of B stars with spectroscopic peculiarities, we can find the Be and the B[e] stars. The Be stars are early-type rapid rotators that present, as their principal characteristic, emission lines of hydrogen and singly ionized metals due to the presence of a gaseous envelope. The B[e] stars present in their spectra heterogeneous features that reveal the presence of regions with very different properties in a gaseous and dusty envelope. Our goal is to study the evolution of the disks around peculiar B stars through the variability of their physical properties and dynamical structure, as well as to set constraints on different models and disk forming mechanisms. Throughout the last decade, we have carried out temporal monitoring of a sample of objects in the near infrared using spectroscopic facilities at the Gemini and Las Campanas Observatories. In the present work, we focus on the classical Be star 12 Vul, for which also optical spectra have been collected quasi-simultaneously. We observed variability in the hydrogen line profiles of 12 Vul, attributed to dissipating and building-up processes of the circumstellar envelope. Also, we found that this Be star presented the $^{12}$CO band heads in emission in one observation. The emission of this molecule has not been previously reported in a Be star, while it is a common feature among B[e] stars. We obtained parameters to describe the $^{12}$CO emitting region and propose different scenarios to explain this intriguing emission.

Rehabilitation of degraded areas in northeastern Patagonia, Argentina: Effects of environmental conditions and plant functional traits on performance of native woody species

Abstract: Degradation processes affect a vast area of arid and semi-arid lands around the world and damage the environment and people’s health. Degradation processes are driven by human productive activities that cause direct and indirect effects on natural resources, such as species extinction at regional scale, reduction and elimination of vegetation cover, soil erosion, etc. In this context, ecological rehabilitation is an important tool to recover key aspects of the degraded ecosystem. Rehabilitation trials rely on the use of native plant species with characteristics that allow them to obtain high survival and growth rates. The aim of this work was to assess the survival and growth of native woody species in degraded areas of northeastern Patagonia and relate them to plant functional traits and environmental variables. We observed high early and late survival rates, and growth rates in Prosopis flexuosa DC. var. depressa F.A. Roig and Schinus johnstonii F.A. Barkley, and low values in Condalia microphylla Cav. and Geoffroea decorticans (Gillies ex Hook. & Arn.) Burkart. Early survival rates were positively associated with specific leaf area (SLA) and precipitation, but negatively associated with wood density, the maximum mean temperature of the warmest month and the minimum mean temperature of the coldest month. Late survival rates were positively associated with SLA and soil organic matter, but negatively associated with plant height and precipitation. The temperature had a positive effect on late survival rates once the plants overcame the critical period of the first summer after they were transplanted to the field. Prosopis flexuosa and S. johnstonii were the most successful species in our study. This could be due to their functional traits that allow these species to acclimatize to the local environment. Further research should focus on C. microphylla and G. decorticans to determine how they relate to productive conditions, acclimation to environmental stress, auto-ecology and potential use in ecological rehabilitation trials.

Doomsday for insects? The alarming decline of insect populations around the world

Abstract: Current rates of extinction exceed largely the standard background rate and all living species can be affected. Insects, the most successful group of eukaryotic organisms from their ancient origin almost 480 my ago are no exception. Despite their fundamental roles in all terrestrial and freshwater ecosystems, insects are victims of the anthropogenic intereference (habitat destruction, overharvesting, pathogens, pesticides, pollution, urbanization, transport of invasive species, and greenhouse gases emissions) that is causing the declination of their populations around the world. Although most insects are not charismatic as many vertebrates or plants, they deserve the same level of protection as other species with which humans are more concerned. It is a duty for all entomologists to study an implement conservation measures of insect species, and educate the general public about their inmense relevance for the Biosphere.

The Early Enlightenment roots of Keynes’ probability concept

Abstract: In the brief preface to A Treatise on Probability, Keynes states, ‘It may be perceived that I have been greatly influenced by W. E. Johnson, G. E. Moore and Bertrand Russell, that is, by Cambridge, which, with great debts to the writers of Continental Europe, yet continues in direct succession the English tradition of Locke, Berkeley and Hume, of Mill and Sidgwick’ (J. M. Keynes, 1921, p. v). The authors who have recently stressed the relevance of Keynes ideas on probability have paid special attention to the influence of the former, but not to that of the latter. This article intends to show that the Treatise on Probability is deeply rooted in the history of probabilistic thinking, particularly in the Early Enlightenment (roughly between 1650 and 1750), before mathematicians claimed ownership over the subject. We find that important aspects of Keynes’ notions were already present in Locke and other Early Enlightenment writers, albeit with some note-worthy differences.