http://repositorio.unne.edu.ar/handle/123456789/72 Thu, 09 Apr 2026 04:44:25 GMT 2026-04-09T04:44:25Z http://repositorio.unne.edu.ar/handle/123456789/60179 Las islas rocosas del Paraje Tres Cerros : un refugio de biodiversidad en el litoral mesopotámico argentino Cajade, Rodrigo; Medina, Walter; Salas, Roberto; Fandiño, Blas; Paracampo, Ariel; García, Ignacio; Pautasso, Andrés; Piñeiro, José Miguel; Acosta, José Luis; Zaracho, Víctor Hugo; Avalos, Adán; Gómez, Fernando; Odriozola, Mariana Paola; Ingaramo, María del Rosario; Contreras, Félix Ignacio; Rivolta, Matías Daniel; Hernando, Alejandra Beatriz; Álvarez, Blanca Beatriz En este artículo difundimos nuestro conocimiento sobre la naturaleza de un paisaje único del litoral mesopotámico argentino, el Paraje Tres Cerros, con el objetivo de valorizar y promover la conservación de la biodiversidad en este sitio. Divulgamos los principales resultados del proyecto de relevamiento y conservación de la fauna de vertebrados, llevado a cabo en el área en los últimos tres años. Finalmente discutimos la problemática originada por los intentos fallidos de creación de una reserva natural en este sitio y brindamos los lineamientos futuros a seguir para lograr la creación de un área de conservación. Tue, 01 Jan 2013 00:00:00 GMT http://repositorio.unne.edu.ar/handle/123456789/60179 2013-01-01T00:00:00Z http://repositorio.unne.edu.ar/handle/123456789/60178 Reseña paleobiogeográfica de los Xenarthra (Mammalia) del Pleistoceno tardío de la región Mesopotámica (Argentina); Palaeobiogeographic review of the Xenarthra (Mammalia) from the late pleistocene of the Mesopotamian region (Argentina) Carlini, Alfredo Armando; Zurita, Alfredo Eduardo; Miño Boilini, Ángel Ramón The palaeontological evidence coming from the late Pleistocene of the Mesopotamian region of Argentina suggest (based mainly in the mammal faunas) that this area is somewhat different to that of the Pampean region and middle-north of Argentina, and shows some palaeofaunistic similitude to that proceeding from the southern Brazil and western Uruguay. In this context, we make a comparative analysis of the Xenarthra palaeofauna of the late Pleistocene of the Argentinean Mesopotamia. The Xenarthra are well represented, with “tropical” and “pampean” taxa. In this palaeobiogeographic context, it is remarkable some probable cases of endemic species, especially among the Cingulata Glyptodontidae Neuryurini and the Tardigrada Scelidotheriinae and Mylodontinae. In addition, two of best represented Xenarthra in the pampean region (that is Megatherium Cuvier and Neosclerocalyptus Paula Couto) are almost absent in the fossil record of the Argentinean Mesopotamia. Finally (and compared with that observed in the Pampean region) the Pleistocene Glyptodontidae are mainly characterized by the genus Panochthus Burmeister and Glyptodon Owen, whose are also common in southern Brazil and western Uruguay. To conclude, it is important to remark that the Xenarthra palaeofauna is an important element to support the biogeographic differentiation of this region during, at least, the late Quaternary. The hypothetical coexistence of two great groups of taxa (“pampeans” and “brasilic”) can be explained by migratory process (mainly retractions and expansions) of the biota stimulated by the frequent cyclic climatic fluctuations occurred in the Pleistocene.; Estudios paleontológicos efectuados en la región Mesopotámica, basados particularmente en la fauna de mamíferos del Pleistoceno tardío-Holoceno temprano (ca. 130-8 ka), muestran algunas diferencias paleofaunísticas y biogeográficas con respecto a la región Pampeana y Centro-norte de Argentina, al tiempo que manifiestan cierta vinculación con el sur de Brasil y oeste de Uruguay. En este contexto, se llevó a cabo un estudio comparativo de los Xenarthra (Mammalia) del Pleistoceno tardío de la región Mesopotámica de Argentina. En líneas generales, los Xenarthra se encuentran bien representados, con taxones de origen “pampeano” y otros de afinidades “brasílicas”. También son destacables ciertos casos de probables endemismos en los Cingulata (Glyptodontidae) y en los Tardigrada (Scelidotheriinae y Mylodontinae). En este contexto, dos de los Xenarthra de mayor frecuencia de regiAstro en la región Pampeana (Megatherium Cuvier y Neosclerocalyptus Paula Couto) están prácticamente ausentes en las unidades portadores de la Mesopotamia. Por último, del elenco pleistoceno de Glyptodontidae propio de la región Pampeana y con registros más frecuentes, aquí sólo se destacan los géneros Panochthus Burmeister y Glyptodon Owen, también comunes en el sur de Brasil y oeste de Uruguay. En síntesis, los Xenarthra demuestran ser un buen elemento para apoyar la hipótesis de una diferenciación paleofaunística y biogeográfica de esta área durante, por lo menos, el Cuaternario tardío. A su vez, la aparente mezcla de taxones de origen “austral” con otros intertropicales puede ser explicada en función de procesos migratorios de expansión y retracción de la biota estimulados por las frecuentes fluctuaciones climático-ambientales del Pleistoceno. Tue, 01 Jan 2008 00:00:00 GMT http://repositorio.unne.edu.ar/handle/123456789/60178 2008-01-01T00:00:00Z http://repositorio.unne.edu.ar/handle/123456789/60177 Ab initio study of the elastic properties of single and polycrystal TiO2, ZrO2 and HfO2 in the cotunnite structure Caravaca, María de los Ángeles; Miño, Julio C.; Pérez, V. J.; Casali, Ricardo Antonio; Ponce, Claudio Ariel In this work, we study theoretically the elastic properties of the orthorhombic (Pnma) high-pressure phase of IV-B group oxides: titania, zirconia and hafnia. By means of the self-consistent SIESTA code, pseudopotentials, density functional theory in the LDA and GGA approximations, the total energies, hydrostatic pressures and stress tensor components are calculated. From the stress–strain relationships, in the linear regime, the elastic constants Ci j are determined. Derived elastic constants, such as bulk, Young’s and shear modulus, Poisson coefficient and brittle/ductile behavior are estimated with the polycrystalline approach, using Voigt–Reuss–Hill theories. We have found that C11, C22 and C33 elastic constants of hafnia and zirconia show increased strength with respect to the experimental values of the normal phase, P21/c. A similar situation applies to titania if these constants are compared with its normal phase, rutile. However, shear elastic constants C44, C55 and C66 are similar to the values found in the normal phase. This fact increases the compound anisotropy as well as its ductile behavior. The dependence of unit-cell volumes under hydrostatic pressures is also analyzed. P–V data, fitted to third-order Birch–Murnaghan equations of state, provide the bulk modulus B0 and its pressure derivatives B 0. In this case, LDA estimations show good agreement with respect to recent measured bulk moduli of ZrO2 and HfO2. Thermo-acoustic properties, e.g. the propagation speed of transverse, longitudinal elastic waves together with associated Debye temperatures, are also estimated. Sun, 07 Jun 2009 00:00:00 GMT http://repositorio.unne.edu.ar/handle/123456789/60177 2009-06-07T00:00:00Z http://repositorio.unne.edu.ar/handle/123456789/60176 Phenolic, volatile compounds, antioxidant, and preservative activity of Argentinian Kabuli chickpea husk extract Camiletti, Ornella Francina; Bergesse, Antonella Estefanía; Prieto, María Cecilia; Quiroga, Patricia Raquel; Ojeda, Gonzalo A.; Sgroppo, Sonia Cecilia; Riveros, Cecilia Gabriela; Grosso, Nelson Rubén The objective of this study was to analyze the chemical composition and antioxidant activity of a chickpea husk polyphenol extract (CPE) obtained from Argentinian Kabuli chickpea and to evaluate its antioxidant effect on the chemical quality of sunflower oil. The polyphenol composition of CPE was analyzed by HPLC–ESI-MS/MS. Antioxidant activity was evaluated by DPPH•, FRAP, ABTS•+, and chelating activity in ferrous ion tests. An accelerated oxidation test in sunflower oil was carried out by applying 0.01, 0.02, and 0.05% p/p CPE and comparing it with BHT (0.02%). Peroxide value, conjugated dienes, and volatile compounds were determined on sunflower oil samples. Twelve polyphenols were identified in the chickpea extract. The CPE showed in vitro antioxidant activity. The lowest doses (0.01% and 0.02%) protected sunflower oil more efficiently against oxidative deterioration than the higher level (0.05%). Chickpea husk extract has a good antioxidant effect on sunflower oil, which helps to preserve the quality properties of this product. Sun, 01 Jan 2023 00:00:00 GMT http://repositorio.unne.edu.ar/handle/123456789/60176 2023-01-01T00:00:00Z