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.

Inferencia multimodelo en ciencias sociales y ambientales

Abstract: Fil: Garibaldi, Lucas Alejandro. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Patagonia Norte; Argentina. Universidad Nacional de Rio Negro; Argentina

Dinosaur footprints in the Early Jurassic of Patagonia (Marifil Volcanic Complex, Argentina): Biochronological and palaeobiogeographical inferences

Abstract: A new dinosaurian track-bearing site, with tridactyl footprints from the Lower Jurassic (pre-middle Pliensbachian) volcanogenic and epiclastic rocks of the Marifil Volcanic Complex, Patagonia, Argentina, is presented and described. The best-preserved footprint, classified as cf. Anomoepus, confirms the utility of the Anomoepus-like tracks for the Early Jurassic biochronology. Palaeobiogeographically, this record supports the idea that the South American Early Jurassic dinosaur fauna presents elements of Pangaean distribution, and others with Gondwanan relationships with prevalent southern African affinities. Dinosaur records from South America between the Rhaetian and the Pliensbachian are very scarce, and this find contributes to the knowledge of early radiation and evolution of Dinosauria.

Un Proceso de Modelización de la Membrana Celular en la Formación del Profesorado en Biología en la Universidad

Abstract: Resumen: El estudio se contextualiza en la formacion inicial del profesorado en Biologia en el ambito de la Universidad, en una linea de trabajo que propone que los espacios de formacion disciplinar en biologia que cursan los estudiantes deben estar informados e intervenidos por modelos y estrategias de ensenanza provenientes de los espacios de formacion en didactica de las ciencias naturales. Se presentan resultados de un proceso de modelizacion de la membrana celular a partir del analisis de un hecho cientifico. Se caracterizan los modelos de partida de los estudiantes, el proceso de modelizacion intermedia y los modelos de arribo, orientados a los aspectos de fluidez y autoensamblaje de las moleculas que componen la membrana. El analisis de las producciones nos permite inferir que los modelos iniciales que construyeron para la situacion propuesta se fueron reelaborando y complejizando, y dan cuenta de una reconstruccion teorica del fenomeno, anclandolo en el modelo cientifico de referencia.

Differential Settlement of Associated Species on Ostrea puelchana d'Orbigny, 1842 (Ostreidae) in Patagonia (Argentina)

Abstract: Ostrea puelchana d'Orbigny, 1842 is a common species of commercial interest in Patagonia and is distributed from Rio Grande do Sul (Brazil) to San Matias Gulf(SMG, Argentina). In SMG, the species develops natural banks that provide irregular surfaces suitable for colonization of organisms. We studied the composition and frequency of encrusting and associated species on O. puelchana shells as well as the preferential settlement of epibionts on different areas within left and right valves. A total of 55 taxa were identified. The dominant groups were Annelida, Foraminifera, Bryozoa and Mollusca in two different oyster banks. The lifestyle of the oyster favors a preferential settlement of epibionts on different valves and areas within the valves. Substratum heterogeneity, reproductive cues, gregarious behavior, protection against predation and/or brooding care could be responsible for this differential settlement. The left valve was more encrusted than the right one. Spirorbinae, Cirratulidae, Foram...

Osteohistological correlates of muscular attachment in terrestrial and freshwater Testudines

Abstract: Sharpey's fibers are considered the anatomical structures integrated to the muscles. Since these fibers leave marks at the microscopic level, their presence and distribution are used as evidence of muscle attachment in extinct and extant forms. In recent years, studies have been focusing on muscle-bone and tendon-bone interaction mostly on mammals. The main objective of this work is to contribute to the morphological and histological knowledge of muscle attachment in other amniotes, such as reptiles, and their variation related to different locomotor habits. In this way, a study was performed on terrestrial and aquatic turtles. The musculature related to the movement of the humerus, and pectoral girdle in Chelonoidis chilensis, Phrynops hilarii and Hydromedusa tectifera was analyzed. Dissections were performed mapping the origins and insertions of each muscle and undecalcified thin sections were performed in specific muscular attachment sites. We found some differences which were not previously reported, related to the insertion of the m. pectoralis, the m. coracobrachialis magnus and the origin of the m. tractor radii. The osteohistology revealed the presence of Sharpey's fibers in the cortex of all the bone elements analyzed. Patterns were established in relation to the orientation and density of Sharpey's fibers, which were used for the categorization of each muscle attachment site. The comparative micro-anatomical study of these areas did not reveal any important differences between terrestrial and freshwater turtles in muscles involved with the rotation, abduction and adduction of the humerus. In this way, the preliminary results suggest an absence of correlation between the distribution and density of Sharpey's fibers between different habitat forms, at least in the bones and species analyzed.