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Rio Gallegos, Argentina

The National University of Austral Patagonia is an Argentine national university in Santa Cruz Province. The university is divided into four campuses, located in the cities of Caleta Olivia , Río Gallegos , San Julián and Río Turbio , and was founded in 1995, by national law 24.446. Wikipedia.

The results of actualistic taphonomic studies in Patagonia aimed at evaluating the preservation potential of vertebrates with different body sizes are presented. Large vertebrates include the guanaco (Lama guanicoe); the South American sea lion (Otaria flavescens), and a flightless bird belonging to the Ratites, the Lesser Rhea (Rhea pennata). Small vertebrates are flying birds and a member of the Spheniscidae Family, the Magellanic penguin (Spheniscus magellanicus). The large vertebrate bone record is the result of a long period of exposure on the ground surface, and its destruction is mainly due to weathering. The flying birds and penguin bone records are instead conditioned by a shorter subaerial exposure time. The future fossil records of these two groups vertebrates will be thus completely different as regards their integrity (sensu Binford, 1981) and their tendency towards spatial and temporal mixing. Source

Montani H.,National University of Patagonia Austral | Schaposnik F.A.,National University of La Plata
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

We construct fermionic Lagrangians with anisotropic scaling z=2, the natural counterpart of the usual z=2 Lifshitz field theories for scalar fields. We analyze the issue of chiral symmetry, construct the Noether axial currents and discuss the chiral anomaly giving explicit results for two-dimensional case. We also exploit the connection between detailed balance and the dynamics of Lifshitz theories to find different z=2 fermionic Lagrangians and construct their supersymmetric extensions. © 2012 American Physical Society. Source

Brunini A.,National University of Patagonia Austral | Zanardi M.,National University of La Plata | Zanardi M.,CONICET
Monthly Notices of the Royal Astronomical Society | Year: 2016

We present numerical simulations of the evolution of synthetic transneptunian binaries (TNBs) under the influence of the solar perturbation, tidal friction, and collisions with the population of classical Kuiper belt objects (KBOs).We show that these effects, acting together, have strongly sculpted the primordial population of TNBs. If the population of classical KBOs have a powerlawsize distribution as the ones that are inferred from recent observational surveys, the fraction of surviving binaries at present would be ~70 per cent of the primordial population. The orbits of the surviving synthetic systems match reasonably well the observed sample. The collisional process excites the mutual orbital eccentricity of the binaries, acting against the effect of tides. Therefore only ~10 per cent of the objects reach total orbital circularization (e ≤ 10-4). In addition, our results predict that the population of contact binaries in the transneptunian region should be small. Ultrawide binaries are naturally obtained by the combined action of Kozai cycles and tidal friction and collisional evolution, being the number and orbital distribution of them very similar to the ones of the observed population. © 2015 The Authors. Source

Escalada J.P.,National University of Patagonia Austral | Arce V.B.,CONICET | Porcal G.V.,National University of Rio Cuarto | Biasutti M.A.,National University of Rio Cuarto | And 3 more authors.
Water Research | Year: 2014

The production of dichlorophen (2,2'-methylenebis(4-chlorophenol), DCP) and its use as an anthelmintic and in pesticide products result in its direct release to the environment. To the purpose of modelling the possible photodegradation routes of DCP sorbed on sediments or suspended particles, the synthesis and characterization of silica nanoparticles modified with DCP (NP-DCP) is reported.The reactivity of NP-DCP with the excited states of riboflavin, a sensitizer usually present in natural waters, and with singlet oxygen were investigated. Comparison of the kinetic results obtained here to those previously reported for irradiated aqueous solutions of DCP allowed the discussion of the effect of adsorption of the pesticide on its photodegradation.We show with the aid of computer simulations that in natural waters the relevance of the different photodegradation routes dichlorophen is very much affected by attachment to sediments. © 2013 Elsevier Ltd. Source

Villagra A.,National University of Patagonia Austral | Alba E.,University of Malaga | Leguizamon G.,National University of San Luis
Computational Intelligence and Neuroscience | Year: 2016

This work presents the results of a new methodology for hybridizing metaheuristics. By first locating the active components (parts) of one algorithm and then inserting them into second one, we can build efficient and accurate optimization, search, and learning algorithms. This gives a concrete way of constructing new techniques that contrasts the spread ad hoc way of hybridizing. In this paper, the enhanced algorithm is a Cellular Genetic Algorithm (cGA) which has been successfully used in the past to find solutions to such hard optimization problems. In order to extend and corroborate the use of active components as an emerging hybridization methodology, we propose here the use of active components taken from Scatter Search (SS) to improve cGA. The results obtained over a varied set of benchmarks are highly satisfactory in efficacy and efficiency when compared with a standard cGA. Moreover, the proposed hybrid approach (i.e., cGA+SS) has shown encouraging results with regard to earlier applications of our methodology. © 2016 Andrea Villagra et al. Source

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