La megafauna del Pleistoceno-Holoceno temprano de la provincia de Córdoba y su comparación con la de Buenos Aires : Sistemática, bioestratigrafía y dinámica faunística

La fauna de megamamíferos pleistocénicos está ampliamente representada en el Cuaternario de Argentina y de otros países de América del Sur (Bolivia, Brasil, Paraguay, Uruguay, Chile, Perú, Venezuela). En la Argentina han sido estudiados en detalle aquellos provenientes del este de la Región Pampeana (provincia de Buenos Aires). Gran parte de esta fauna ha provisto la base bioestratigráfica sobre la que se sustenta el esquema cronológico para el Cenozoico superior continental de América del Sur. Sin embargo, la aplicación de este esquema en la provincia de Córdoba es aún incipiente. Si bien, en los últimos veinte años, se han publicado varios estudios geológicos y estratigráficos que brindan un marco regional adecuado para estudios bioestratigráficos del Cenozoico tardío, las contribuciones paleontológicas son en su mayoría hallazgos puntuales y análisis preliminares de asociaciones faunísticas. El objetivo de este trabajo es contribuir al conocimiento de la bioestratigrafía de la Argentina a través del estudio de los megamamíferos del Pleistoceno-Holoceno temprano del actual territorio de la provincia de Córdoba, compararlos con aquellos de la provincia de Buenos Aires y ubicarlos en un contexto cronoestratigráfico/geocronológico local. Para cumplir con dicho objetivo, se realizó una búsqueda y posterior selección de los materiales a estudiar, con procedencia estratigráfica y geográfica precisa; se seleccionaron materiales de antiguas colecciones (e.g. Museo Universitario Florentino y Carlos Ameghino [Rosario], Museo Argentino de Ciencias Naturales “Bernardino Rivadavia” [Ciudad Autónoma de Buenos Aires], Museo de La Plata) y colecciones de museos regionales de la provincia de Córdoba, en su mayoría inéditas (e.g. Museo Aníbal Montes, Archivo Gráfico y Museo Histórico de la ciudad de San Francisco, colección de paleontología de vertebrados de la Universidad Nacional de Río Cuarto). Se estudiaron seis localidades: San Francisco, Miramar, Río Cuarto, Isla Verde, Valle de Traslasierra y Los Reartes. Se realizaron salidas de campo a todas las localidades mencionadas con el objeto de reconocer los estratos sedimentarios de donde provienen los materiales analizados, levantar los perfiles correspondientes y ubicar antiguas localidades con fósiles (materiales de colecciones antiguas). Se revisaron las colecciones paleontológicas con materiales Tipo y referidos con el objeto de comparar e identificar los materiales provenientes de la provincia de Córdoba. Para realizar el análisis bioestratigráfico se describieron y correlacionaron las facies sedimentarias, en conjunto con su fauna asociada, se establecieron primeros registros y se confirmaron presencias y asociaciones de taxones, que posteriormente se compararon con los establecidos para la provincia de Buenos Aires. De esta manera, fue posible establecer el valor de algunas especies como fósiles guía para el lapso Pleistoceno – Holoceno temprano del actual territorio de la provincia de Córdoba y compararlas con las propuestas para Buenos Aires.Facultad de Ciencias Naturales y Muse

A reassessment of the taxonomic status of Paraglyptodon Castellanos, 1932 (Mammalia, Cingulata, Glyptodontia)

Castellanos described and published about new genera of glyptodonts, according to a phylogenetic scheme mainly based on the evolution of the external surface of the dorsal carapace. Among these new genera, Castellanos proposed Paraglyptodon as the predecessor of Glyptodon, and included within Paraglyptodon all known species of Glyptodontinae recovered from “horizontes pre-Ensenadenses”, and within Glyptodon all known species from “Horizontes pampeanos”, restricting the latter to the Quaternary. All the species that belong to Paraglyptodon, that is Paraglyptodon chapalmalensis, Paraglyptodon uquiensis, Paraglyptodon dubius, and Paraglyptodon paranensis were established based on one, two or few osteoderms, mostly from the dorsal carapace. Regarding P. paranensis and P. dubius, Oliva and collaborators consider the first as a nomen vanum, representing an indeterminate Glyptodontinae, and the second as a synonym of P. chapalmalensis. Upon re-examination of the holotypes of P. chapalmalensis and P. uquiensis together with their comparison with other well-known specimens of glyptodonts, mainly with Glyptodon (of both juvenile and adult stages), we found the same ornamentation in different sections of the dorsal carapaces, particularly in P. chapalmalensis and in juvenile stages of Glyptodon spp.We could not identify features that would allow us to make a distinction between the holotype of P. uquiensis and Glyptodon spp. Therefore, we consider that a new taxon guide for naming the Upper Chapadmalalan biozone is necessary. The biostratigraphic range of Glyptodon could possibly be extended to the late Pliocene. However, new records and studies are needed to verify the existence of this taxon in the Chapadmalalan Stage/Age in its type locality.Facultad de Ciencias Naturales y Muse

Considerations Of E-Commerce Within A Globalizing Context

The objective of this work, is to analyze the meaning of electronic commerce in our days taking into account the information technologies; it also will analyze their adjustments, their trends and applications of the same, in the Business to Consumer Relations (B2C), Business to Employee (B2E) and Business to Administration (B2A), Consumer to Consumer (C2C), Citizen to Government (C2G), Business to Government (B2G) and, Business to Business (B2B), as well as how information systems have been very useful to reduce costs, getting technology to change from being an operating support tool to become a strategy one, to increase the sales volume and the profits of the business as a result of this. The trend being taken by businesses and consumers has increased the participation of the companies which apply it in a comprehensive manner, since they reach international markets, while also face another kind of competition that takes place in a global market. We conclude that electronic commerce will remain a tool of great importance to efficiently manage the chains of supply between businesses and consumers through the Internet which allows an integration to reduce costs of ordering, distribution, administration and delivery of input materials

Competent or Not?: Exploring Adaptions to the Neo-Behaviorist Paradigm in a Sport Marketing Course

Educators and administrators are exploring competency-based education as an effective and efficient method to facilitate student learning. This reinforces a burgeoning neo-behaviorist movement in higher education which seeks to synthesize such behaviorist approaches with the cognitive focus of the last 20 years. The current research examines the outcomes in three years of a sport marketing class that blends cognitive-based and competency-based pedagogy. The first half of the course is primarily self-paced, with regular quizzes checking student mastery, while the second half of the course has students work in teams on marketing-related projects; a final examination assesses overall student learning. The research revealed that the blended approach resulted in complementary strategies which partially addressed the conventional criticisms of both cognitive- and competency-based pedagogical approaches. The study used paired sample t-tests to compare results on quizzes versus the final exam (N=111 students comprising 36,787 total student-responses), finding that the course's hybrid structure develops student learning in both lower-order and higher-order thinking (as per Bloom's taxonomy). In addition to this approach's pedagogical benefits, the structure may have implications for administrators and educators facing challenges in terms of student enrollment, budgets, and expectations of graduates

El registro de mamíferos fósiles del Pleistoceno tardío de la Laguna Mar Chiquita, provincia de Córdoba, Argentina

La Laguna Mar Chiquita, ubicada en el nordeste de la provincia de Córdoba, es una depresión de origen tectónico formada durante el Pleistoceno como consecuencia de las grandes fracturas longitudinales que originaron distintos bloques en el área de la Llanura Chacopampeana. Si bien se han realizado estudios detallados de la evolución geomorfológica y de la estratigrafía del Cuaternario de esta zona, el registro paleontológico ha sido mencionado en escasas oportunidades. En la costa sudeste de la laguna aflora un nivel loéssico de estructura maciza, ubicado aproximadamente dos metros por debajo del suelo actual y asignado tentativamente a la Formación Tezanos Pinto (Pleistoceno tardío-Holoceno temprano), que presenta un importante registro de mamíferos fósiles. En esta contribución se describe y analiza en forma preliminar la asociación de taxones procedentes de este nivel, cuyos materiales se encuentran depositados en el Museo Aníbal Montes de la localidad de Miramar. Esta asociación incluye Eutatus sp. (osteodermos aislados), Lomaphorus sp. (tubo caudal y fragmento de coraza), Neosclerocalyptus sp. (fragmento de cráneo, coraza y tubo caudal), Panochthus sp. (osteodermos aislados, porción de tubo caudal), Glyptodon sp. (osteodermos aislados), Scelidotherium aff. S. leptocephalum Owen (rama mandíbular con m2-m4), Toxodon sp. (porción de rama mandibular con m3) y Equus (Amerhippus) aff. E. (A.) neogaeus Lund (molares superiores e inferiores aislados). Si bien la asignación taxonómica de la mayoría de los taxones es genérica y constituye una asociación típica del Cenozoico superior, la presencia de E. (A.) neogaeus, taxón exclusivo de la biozona de E. (A.) neogaeus y base bioestratigráfica del Lujanense (Pleistoceno tardío-Holoceno temprano), nos permite inferir dicha edad para el nivel portador. Esto es consistente con la edad estimada para la Formación Tezanos Pinto en el sudeste de Córdoba y oeste de Santa Fé. Estudios radiométricos y sedimentológicos ulteriores permitirán corroborar la hipótesis actualmente planteada.Sesiones libresFacultad de Ciencias Naturales y Muse

Multilayered Analyses of the Experiences of Undocumented Latinx College Students

Being the target of constant discrimination and marginalization can often cause intense negative psychological reactions and shame for undocumented students. The following qualitative study describes past and current undocumented Latinx students’ experiences of educational inequality in higher education influenced by labels associated with “being undocumented.” In this study we used a constructivist theoretical perspective which enabled us to focus on undocumented participants’ perspectives, experiences, meaning-making processes, values, and beliefs. Data was collected through hour-long, semi-structured interviews with five undocumented students. Student narratives were analyzed using a multi-layered analysis approach: (1) narrative, (2) thematic, and (3) critical incident analysis. Findings for this study provided insight on the narratives of carrying labels, themes associated with various labels, and critical incidents in the narratives and lives of undocumented students. Through our findings, we are able to contribute to existing literature and provide directions for future research

Analysis of Bulked and Redundant Accessions of Brassica Germplasm Using Assignment Tests of Microsatellite Markers

This study was conducted to determine if Brassica germplasm bulks created and maintained by the USDA-ARS North Central Plant Introduction Station (NCRPIS) were made with genetically indistinguishable component accessions and to examine newly identified putative duplicate accessions to determine if they can be bulked. Using ten microsatellite primer pairs, we genotyped two bulks of B. rapa L. ssp. dichotoma (Roxb.) Hanelt comprising four accessions and three bulks of B. rapa L. ssp. trilocularis (Roxb.) Hanelt comprising fourteen accessions, as well as four pairs of putatively duplicate accessions of B.␣napus L. Assignment tests on ten individual plants per accession were conducted using a model-based clustering method to arrive at probabilities of likelihood of accession assignment. The assignment tests indicated that one of the two bulks of B. rapa ssp. dichotoma involves genetically heterogeneous accessions. It was observed in the B. rapassp. trilocularis bulks that the component accessions could be differentiated into groups, with misassignments observed most frequent within groups. In B. napus, only one of the four pairs of putative duplicates showed significant genetic differentiation. The other three pairs of putative duplicates lack differences and support the creation of bulks. The results of the assignment tests were in agreement with cluster analyses and tests of population differentiation. Implications of these results in terms of germplasm management include the maintenance and/or re-creation of someBrassica germplasm bulks by excluding those accessions identified as being unique in this study

Ethanol and Caffeine Effects on Social Interaction and Recognition in Mice: Involvement of Adenosine A2A and A1 Receptors

Ethanol and caffeine are frequently consumed in combination and have opposite effects on the adenosine system: ethanol metabolism leads to an increase in adenosine levels, while caffeine is a non-selective adenosine A1/A2A receptor antagonist. These receptors are highly expressed in striatum and olfactory tubercle, brain areas involved in exploration and social interaction in rodents. Ethanol modulates social interaction processes, but the role of adenosine in social behavior is still poorly understood. The present work was undertaken to study the impact of ethanol, caffeine and their combination on social behavior, and to explore the involvement of A1 and A2A receptors on those actions. Male CD1 mice were evaluated in a social interaction three-chamber paradigm, for preference of conspecific vs. object, and also for long-term recognition memory of familiar vs. novel conspecific. Ethanol showed a biphasic effect, with low doses (0.25 g/kg) increasing social contact and higher doses (1.0-1.5 g/kg) reducing social interaction. However, no dose changed social preference; mice always spent more time sniffing the conspecific than the object, independently of the ethanol dose. Ethanol, even at doses that did not change social exploration, produced amnestic effects on social recognition the following day. Caffeine reduced social contact (15.0-60.0 mg/kg), and even blocked social preference at higher doses (30.0-60.0 mg/kg). The A1 antagonist Cyclopentyltheophylline (CPT; 3-9 mg/kg) did not modify social contact or preference on its own, and the A2A antagonist MSX-3 (1.5-6 mg/kg) increased social interaction at all doses. Ethanol at intermediate doses (0.5-1.0 g/kg) was able to reverse the reduction in social exploration induced by caffeine (15.0-30.0 mg/kg). Although there was no interaction between ethanol and CPT or MSX-3 on social exploration in the first day, MSX-3 blocked the amnestic effects of ethanol observed on the following day. Thus, ethanol impairs the formation of social memories, and A2A adenosine antagonists can prevent the amnestic effects of ethanol, so that animals can recognize familiar conspecifics. On the other hand, ethanol can counteract the social withdrawal induced by caffeine, a non-selective adenosine A1/A2A receptor antagonist. These results show the complex set of interactions between ethanol and caffeine, some of which could be the result of the opposing effects they have in modulating the adenosine system