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17 results on '"Barros, María P."'

1. Optimal equilibrium for a reformulated Samuelson economical model

Author

Ortega, Fernando, Barros, Maria Philomena, and Kalogeropoulos, Grigoris

Subjects
Mathematics - Dynamical Systems
Abstract

This paper studies the equilibrium of an extended case of the classical Samuelson's multiplier-accelerator model for national economy. This case has incorporated some kind of memory into the system. We assume that total consumption and private investment depend upon the national income values. Then, delayed difference equations of third order are employed to describe the model, while the respective solutions of third order polynomial, correspond to the typical observed business cycles of real economy. We focus on the case that the equilibrium is not unique and provide a method to obtain the optimal equilibrium.

Published
2017

2. Guanaco Hunting Strategies in the Southeastern Pampas During the Late Holocene

Author

Kaufmann, Cristian A., Álvarez, María C., Messineo, Pablo G., Barros, María P., Bonomo, Mariano, Heider, Guillermo, Correia Dantas, Eustógio W., Series Editor, Rabassa, Jorge, Series Editor, Sluyter, Andrew, Series Editor, Belardi, Juan Bautista, editor, Bozzuto, Damián Leandro, editor, Fernández, Pablo Marcelo, editor, Moreno, Enrique Alejandro, editor, and Neme, Gustavo Adolfo, editor

Published
2021
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8. Aportes del estudio de los procesos de formación de sitio para el análisis de los restos humanos del sitio Laguna Muscar 2 (Lamadrid, Buenos Aires).

Author

Kaufmann, Cristian, Bellinzoni, Jonathan, Álvarez, María C., Favier Dubois, Cristian, Barros, María P., González, Mariela E., Kaufmann, Cristian, Bellinzoni, Jonathan, Álvarez, María C., Favier Dubois, Cristian, Barros, María P., and González, Mariela E.

Abstract

In this article we present the results of the analysis of a significantly disturbed human burial, recovered at the archaeological site Laguna Muscar 2 (Lamadrid County, province of Buenos Aires). The main objectives were to characterize the burial, to determine the burial type, and to evaluate the site formation processes that were responsible for its final configuration. To achieve these goals, all the anatomical units were identified and quantified, taphonomic modifications were registered, and the spatial distribution of the elements in the sedimentary matrix was studied. The results indicated that the burial was composed by an adult female individual, with artificial (planofrontal) cranial deformation and some degenerative pathology. The type of burial was determined as primary and the radiocarbon date indicated an age of ca. 2500 years C14 AP. The results showed the importance of implementing the study of formation processes when analyzing assemblages disturbed by fossorial animals. Finally, the resulting data were discussed together with the studies available for the microregion of the Salado creek basin., En este trabajo se presentan los resultados del análisis de un entierro humano altamente perturbado, recuperado en el sitio Laguna Muscar 2 (partido de Gral. Lamadrid, provincia de Buenos Aires). Los principales objetivos fueron caracterizar el entierro, determinar la modalidad del mismo y evaluar los procesos de formación responsables de su configuración final. Para esto se llevó a cabo la identificación y cuantificación de las unidades anatómicas, en conjunto con el estudio de las modificaciones tafonómicas y la distribución espacial de los elementos en la matriz sedimentaria. Los resultados indicaron que el entierro estaba conformado por un individuo femenino adulto, con deformación craneana artificial de tipo tabular erecta planofrontal y presencia de algunas patologías degenerativas. La modalidad de entierro fue determinada como primaria y el fechado radiocarbónico efectuado arrojó una edad de ca. 2500 años C14 AP. Los resultados mostraron la importancia de implementar el estudio de los procesos de formación en el análisis de conjuntos perturbados por animales de hábitos fosoriales. Finalmente, estos datos fueron discutidos junto con los estudios disponibles para la microrregión de la cuenca del arroyo Salado.

Published
2019

11. Preclinical studies of toxicity and safety of the AS-48 bacteriocin.

Author

Cebrián, Rubén, Rodríguez-Cabezas, M. Elena, Martín-Escolano, Rubén, Rubiño, Susana, Garrido-Barros, María, Montalbán-López, Manuel, Rosales, María José, Sánchez-Moreno, Manuel, Valdivia, Eva, Martínez-Bueno, Manuel, Marín, Clotilde, Gálvez, Julio, and Maqueda, Mercedes

Abstract

• AS-48 is a 70-residue circular bacteriocin produced by Enterococcus strains. • Toxicity of AS-48 in in vitro and in vivo models has been evaluated. • The haemolytic activity and lacks of pro-inflammatory effects of AS-48 are minimal. • AS-48 has scarce ability to cause loss of cell viability at therapeutic concentrations. • AS-48 is a promising therapeutic agent against a vast array of microbial infections. The in vitro antimicrobial potency of the bacteriocin AS-48 is well documented, but its clinical application requires investigation, as its toxicity could be different in in vitro (haemolytic and antibacterial activity in blood and cytotoxicity towards normal human cell lines) and in vivo (e.g. mice and zebrafish embryos) models. Overall, the results obtained are promising. They reveal the negligible propensity of AS-48 to cause cell death or impede cell growth at therapeutic concentrations (up to 27 μM) and support the suitability of this peptide as a potential therapeutic agent against several microbial infections, due to its selectivity and potency at low concentrations (in the range of 0.3–8.9 μM). In addition, AS-48 exhibits low haemolytic activity in whole blood and does not induce nitrite accumulation in non-stimulated RAW macrophages, indicating a lack of pro-inflammatory effects. The unexpected heightened sensitivity of zebrafish embryos to AS-48 could be due to the low differentiation state of these cells. The low cytotoxicity of AS-48, the absence of lymphocyte proliferation in vivo after skin sensitization in mice, and the lack of toxicity in a murine model support the consideration of the broad spectrum antimicrobial peptide AS-48 as a promising therapeutic agent for the control of a vast array of microbial infections, in particular, those involved in skin and soft tissue diseases. [ABSTRACT FROM AUTHOR]

Published
2019
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13. Ritual persistence among hunter and gatherers of the pampean llanura of Argentina

Author

Politis, Gustavo Gabriel, Messineo, Pablo Gerónimo, Kaufmann, Cristian A., Barros, María P., Álvarez, María C., Di Prado, Violeta Soledad, and Scalise, Rocío

Subjects
Sitios de encuentro, Encounter sites, Ritual deposit, Cazadores-recolectores pampeanos, Pampean hunters-gatherers, Arqueología, Depósito ritual
Abstract

En este trabajo se discuten y resumen las evidencias obtenidas como resultado de estudios multidisciplinarios —geológicos, paleoambientales, líticos, arqueofaunísticos y tafonómicos, entre otros— del sitio Calera, ubicado en las Sierras Bayas, región pampeana, Argentina. Este sitio se presenta como un depósito excepcional de origen ritual producido probablemente como consecuencia de varias ceremonias realizadas en las inmediaciones. En este lugar se registraron cuatro cubetas excavadas intencionalmente, fechadas entre c. 3400 y 1750 a.p., que fueron rellenadas con materiales arqueológicos y sedimentos alóctonos. Entre los materiales se destacan más de 6000 artefactos líticos de diferentes materias primas locales y no locales, aproximadamente 400 instrumentos líticos, 310 tiestos de alfarería (algunos con motivos figurativos antropomorfos), 1760 restos de pigmentos minerales, cuatro moluscos marinos, una hacha de granito, una cuenta de valva, una estatuilla cilíndrica decorada de forma fálica y varios instrumentos sobre hueso y astas. También se registró un número aún indeterminado (varios miles) de restos óseos de 16 especies de mamíferos —entre ellos guanaco, venado, carnívoros, mesomamíferos y micromamíferos—, seis aves, tres peces y, posiblemente, reptiles. Las características excepcionales del sitio permiten abordar aspectos ideacionales y sociales de los cazadoresrecolectores pampeanos y discutir la visibilidad arqueológica de los sitios de encuentro., In this paper, several lines of evidence (geology, paleoenvironment, lithic and faunal analysis, among others) from the Calera site (Sierras Bayas, pampean region, Argentina) are summarized and discussed. The cultural deposit seems to be a ritual site, formed by the occurrence of several ceremonies during the late Holocene. In the Calera site, four cubetas (pits) were intentionally excavated, between ca. 3400 and 1750 years BP, and filled with a great amount and variety of archaeological materials as well as alochtonous sediments. Among the recovered materials, there were more than 6000 of lithic artefacts, 310 pottery sherds (some of them with antropomorphic motifs),1760 pieces of mineral pigments, 4 marine molluscs, a shell bead, a granite axe, several instrument made of bone and deer antler, and a phallic statuette. A yet undetermined number (several thousands) of faunal remains were from 16 different mammal species (guanaco, pampean deer, carnivores, mesomammals, micromammals, among others), 6 avian species, 3 fishes and probably reptiles. The exceptional features of the site allow the study of social and ideational aspects of the pampean hunter-gatherers and discussion of the archaeological signatures of the site in terms of nonhierarchical societies., Facultad de Ciencias Naturales y Museo

Published
2005

16. Changes in the speciation, partitioning and phytoavailability of chromium induced by organic soil amendments

Author

Rendina, Alicia, Josefina Barros, María, and Fabrizio de Iorio, Alicia

Abstract

AbstractThis study investigated the effect of two organic amendments (compost of cattle ruminai content and Sphagnum-moss peat) on the reduction of hexavalent chromium and the distribution of this metal among the main solid phases of a soil with low organic matter content treated with different levels of Cr(VI) (0–2000 mg Cr kg−1soil). At the same level of added organic carbon, the peat reduced Cr(VI) added to the soil from 250 to 2000 mg kg−1, with 100% efficiency. The reduction efficiency of the compost, however, decreased with the increasing dose of Cr(VI) soil. The distribution of Cr between the different soil components was evaluated by a sequential chemical extraction procedure. The concentration of water-soluble and exchangeable Cr decreased with the addition of organic amendments to the soil, whereas Cr increased in the organic fraction. The effect of added organic material on the Cr absorption was examined with two ornamental plants (Melissa officinalisand Begonia semperflorens). The increased Cr(VI) in the soil increased the Cr concentration in plant tissues. The addition of organic matter produced a greater aerial biomass for each level of added Cr in comparison with unamended soil. Sphagnummoss peat was more effective than the compost to decrease the total Cr and the Cr(VI) concentration in the water-soluble and exchangeable fraction of soil, thereby reducing the Cr accumulation in plants tissues and phytotoxic symptoms.

Published
2011
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