Vertebrados amniotas y paleoambiente de la Amazonía peruana durante el mioceno medio (Arco de Fitzcarrald)

Publicación a texto completo no autorizada por el autorDescribe y discute acerca de los fósiles de vertebrados amniotas hallados en la Amazonia peruana, entre los departamentos de Ucayali y Madre de Dios, en el área conocida como Arco de Fitzcarrald. Los fósiles del área de Fitzcarrald representan la fauna existente en el Mioceno medio y son equivalentes cronológicamente a la fauna de La Venta (Colombia) datada entre 13.8-11.8 Ma. Esta biocorrelación responde a la presencia de fauna correspondiente al “Miocochilius assemblage zone” (o “Zona de Conjunto Miocochilius”), bioestrato definido por las primeras y últimas apariciones del notoungulado interatérido Miocochilius, el fósil más común de La Venta y también presente en la fauna de Fitzcarrald. La fauna de vertebrados amniotas de Fitzcarrald está compuesta por los órdenes Crocodylia, Testudines, Xenarthra, Rodentia, Litopterna, Notoungulata, Astrapoteria y Cetacea. La composición taxonómica general de la fauna de Fitzcarrald ha sido comparada con otras cinco faunas del Mioceno medio sudamericano: La Venta, Colombia; Quebrada Honda, Bolivia; Acre, Brasil; Urumaco, Venezuela y Collón-Curá; Argentina. De todas las faunas con las que ha sido comparada, la fauna de Fitzcarrald presenta mayor similaridad con la fauna de La Venta con 11 géneros de mamíferos compartidos de los 18 géneros identificados y 6 géneros de reptiles compartidos de los 11 identificados. Los cocodrilos presentes en Fitzcarrald muestran variados morfotipos craneanos que evidencian una gran variedad de ecologías alimenticias y segregación de nichos. En cuanto a los mamíferos sobresalen aquellos de hábitos terrestres y braquiodontes, condición asociada a hábitos ramoneadores. En cuanto a diversidad sobresalen los taxa Xenarthra y Rodentia. El área correspondiente al Arco de Fitzcarrald en el Mioceno medio formaba parte de una extensa cuenca hidrográfica conocida como lago-mar Pebas por sus características mixtas marinas y lacustres. Este enorme cuerpo de agua se extendía al interior de la cuenca amazónica y es considerado como uno de los más grandes en la historia de la Tierra

Testing Foundational Tenets of Stable Isotope Ecology Analyses in Neotropical Mammalian Communities, and Implications for Terrestrial Paleoecology

Stable isotope analyses are powerful tools for reconstructing ancient ecologies and ecosystems, as they are independent of morphology and directly reflect dietary ecology. The application of stable isotope analyses, however, is not without limitations, as determination of food web dynamics using these methods often relies on poorly tested assumptions. The guiding thread of this thesis is the testing of foundational cornerstones on which these methods rely, in order to validate the suitability of applying these techniques to different mammalian clades, and to more reliably and confidently interpret the isotopic signals preserved in extinct organisms. The first chapter of this thesis tests the validity of an important assumption behind the interpretation of stable carbon isotope analyses for understanding diet in terrestrial mammalian herbivores: if, as assumed for almost two decades, mammalian bioapatite δ¹³C is enriched by 14‰ relative to dietary δ¹³C. By analyzing new isotopic data from a never before assessed herbivorous group spanning a broad range of body masses—sloths (Xenarthra, Mammalia)— and other mammals with experimentally controlled or observationally known diets, I discovered considerable variation in diet–bioapatite δ¹³C enrichment among mammals. Statistical tests (ordinary least squares, quantile, robust regressions, Akaike information criterion model tests) documented independence from phylogeny, and a previously unrecognized strong and significant correlation of δ¹³C enrichment with body mass for all mammalian herbivores. A single-factor body mass model outperformed all other single-factor or more complex combinatorial models evaluated, including for physiological variables (metabolic rate and body temperature proxies), and indicated that body mass alone predicts δ¹³C enrichment. These analyses, spanning more than 5 orders of magnitude of body sizes, yield a size-dependent prediction of isotopic enrichment across Mammalia and for distinct digestive physiologies, permitting reconstruction of foregut versus hindgut fermentation physiologies for fossils and refined mean annual paleoprecipitation estimates based on δ¹³C of mammalian bioapatite. Second, I sought to evaluate the existing paradigm governing identification of closed canopy rainforests in the fossil record using mammalian δ¹³C data: the presence of mammals with dietary δ¹³C <-31‰, which has only been observed in closed canopy rainforests in Equatorial Africa, the only other tropical ecosystem sampled extensively. This chapter provides a characterization of δ¹³Cbioapatite, δ¹³Chair and δ¹⁵Nhair of a modern mammalian community in western Amazonia, in Peru, to test if the isotopic structure of mammals in this Neotropical ecosystem is similar to those in African tropical rainforests. The results indicate that despite their marked geographical and taxonomic differences, median δ¹³Cdiet values from closed canopy rainforests in Amazonia (-27.4‰) and equatorial Africa (-26.9‰) are not significantly different. Amazonian mammals, however, seem to exploit a narrower spectrum of dietary resources than equatorial African mammals, as depicted by the absence of highly negative δ¹³Cdiet values previously proposed as indicative of rainforests (<-31‰). I hypothesize that differential effects of late Pleistocene extinction may be responsible for the ecological disparities among the two rainforests, by significantly reducing evolutionary time and dietary breadth reflected in the modern Amazonian mammalian community. Finally, the third chapter of this dissertation evaluates assumptions behind δ¹⁵N amino acid compound specific analyses in order to test the controversial hypothesis of carnivory and consumption of proteins of animal origin in fossil sloths. This analytical technique relies on three main assumptions. First, that the offset between the δ¹⁵N of glutamic acid (δ¹⁵NGlx) and phenylalanine (d15NPhe) in the organism under study will increase with increasing trophic level. Second, that the offset between δ¹⁵NGlx and δ¹⁵NPhe at the base of the food chain is relatively constant and has a value of -8.4‰ for C3 ecosystems. Third, that the trophic discrimination factor in all ecosystems (the difference in δ¹⁵NGlx relative to δ¹⁵NPhe with increasing trophic level) is 7.6‰. The results of my experiments conducted on extant xenarthrans (sloths and anteaters) with controlled diets document that only the first assumption holds true. Rather than relying on an equation with constants introducing uncertainties and that are not applicable to organisms feeding on a combination of items of different origin (e.g., C3 + C4 plants), δ¹⁵NGlx and δ¹⁵NPhe values by themselves can accurately reconstruct the trophic position of organisms. Indeed, the results on δ¹⁵NGlx and δ¹⁵NPhe herein obtained for five xenarthran species in controlled feeding experiments, combined with mammalian data available from the literature, show strong and significant correlations between these two AAs and with trophic positions. Both the TP equation and the regression analyses of δ¹⁵NGlx and δ¹⁵NPhe suggest that the Pleistocene fossil ground sloths and were not pure herbivores as commonly presumed, but rather that they were both mixed feeders/omnivores, incorporating items of animal origin in their diets

Los mamíferos del Mioceno y Plioceno de Espinar (Cusco): antecedentes y proyecto

En noviembre de 2002, durante la obra de excavación de un reservorio de agua para irrigación, trabajadores de la Villa Accocunca (Alto Pichigua) se toparon con los restos fosilizados de un gran «armadillo», a casi tres metros de profundidad. Durante el proceso de colecta, realizado por uno de los autores (JG), colaboradores del INC-CUS y pobladores locales, solo fue posible apreciar el caparazón, los anillos y el tubo caudal. Sin embargo, la limpieza y conservación de los huesos en el laborat..

A New 13 Million Year Old Gavialoid Crocodylian from Proto-Amazonian Mega-Wetlands Reveals Parallel Evolutionary Trends in Skull Shape Linked to Longirostry

Gavialoid crocodylians are the archetypal longirostrine archosaurs and, as such, understanding their patterns of evolution is fundamental to recognizing cranial rearrangements and reconstructing adaptive pathways associated with elongation of the rostrum (longirostry). The living Indian gharial Gavialis gangeticus is the sole survivor of the group, thus providing unique evidence on the distinctive biology of its fossil kin. Yet phylogenetic relationships and evolutionary ecology spanning ~70 million-years of longirostrine crocodylian diversification remain unclear. Analysis of cranial anatomy of a new proto-Amazonian gavialoid, Gryposuchus pachakamue sp. nov., from the Miocene lakes and swamps of the Pebas Mega-Wetland System reveals that acquisition of both widely separated and protruding eyes (telescoped orbits) and riverine ecology within South American and Indian gavialoids is the result of parallel evolution. Phylogenetic and morphometric analyses show that, in association with longirostry, circumorbital bone configuration can evolve rapidly for coping with trends in environmental conditions and may reflect shifts in feeding strategy. Our results support a long-term radiation of the South American forms, with taxa occupying either extreme of the gavialoid morphospace showing preferences for coastal marine versus fluvial environments. The early biogeographic history of South American gavialoids was strongly linked to the northward drainage system connecting proto-Amazonian wetlands to the Caribbean region

El secuestro institucional femenino: las violencias invisibilizadas.

Este estudio va a abordar la situación de las mujeres presas en España desde tres fuentes deinformación. La primera, fundamentada en una revisión bibliográfica, estudia la evolución del sistemapenitenciario desde sus inicios (siglo XVII) hasta la actualidad. A continuación, revisamos la legislaciónvigente y los módulos habilitados para la población penitenciaria femenina. La segunda línea detrabajo, sustentada en estudios e informes cuantitativos, analiza el perfil de las mujeres encarceladaspara entender el contexto del que parten y si este guarda relación con los motivos de suencarcelamiento. Por último, la tercera fuente de información procede de las entrevistas realizadas ados profesionales (trabajador social y educadora social) del Centro Penitenciario de Mallorca, quecuenta con módulo de mujeres en el Estado español. El apartado de conclusiones presenta una críticaal sistema penitenciario actual centrada en las desigualdades existentes entre hombres y mujeres.Palabras clave: Mujer, maternidad, género, desigualdad, prisión.<br /

Herramientas de control basadas en lean management y su influencia en la gestión de ventas de una comercializadora

RESUMEN El presente trabajo tiene como objetivo general determinar la influencia de la implementación de herramientas de control basadas en Lean Management en la gestión de ventas de la empresa B&H Drilling Tools S.A.C., para cumplir el mismo se realizó un diagnóstico de los procesos de la empresa; asimismo se identificaron las oportunidades de mejora y se diseñó una propuesta de mejora empleando herramientas de control basadas en Lean Management, esta propuesta se basó en la metodología lean, y se aplicó herramientas como VSM, mapa de procesos, diagrama de flujo, los cinco por qué, pronósticos de demanda, clasificación ABC y gráfico de control; los resultados de la propuesta fueron positivos, pues se logró reducir el tiempo de ciclo total en un 50.64%, el tiempo sin valor agregado en un 41.24%, incrementando la eficiencia de las operaciones y la calidad de servicio, asimismo se proyectan mejores indicadores de ventas para el periodo 2019. El análisis financiero de la solución propuesta presenta un Valor Actual Neto de S/ 288,053.68 y una tasa interna de retorno (TIR) DE 186.47% el cual es superior al valor del WACC de 14.00%; por tanto, se confirma la factibilidad económica-financiera de la propuesta.ABSTRACT The general objective of this work is to determine the influence of the implementation of control tools based on Lean Management in the sales management of the company B & H Drilling Tools S.A.C., to accomplish the same, a diagnosis of the company's processes was made; The improvement opportunities were also identified and an improvement proposal was designed using control tools based on Lean Management, this proposal was based on the lean methodology, and tools such as VSM, process map, flow chart were applied, all five what, demand forecasts, ABC classification and control chart; the results of the proposal were positive, since it was possible to reduce the total cycle time by 50.64%, the time without added value by 41.24%, increasing the efficiency of the operations and the quality of service; sales for the 2019 period. The financial analysis of the proposed solution has a Net Present Value of S / 288,053.68 and an internal rate of return (IRR) of 186.47%, which is higher than the WACC value of 14.00%; therefore, the economic-financial feasibility of the proposal is confirmed

Los mamíferos del Mioceno y Plioceno de Espinar (Cusco): expedición y resultados preliminares del proyecto

En mayo del presente año, como parte del proyecto de investigación «Primera fauna nativa del Mio-Plioceno del Perú (Espinar, Cusco): un vistazo a la historia evolutiva de Perú y Bolivia» se realizó una expedición paleontológica y geológica a la altiplanicie Yauri que reveló la presencia de nuevos vertebrados fósiles y la existencia de localidades con singulares grados de preservación. Los vertebrados registrados en la provincia de Espinar estaban, hasta hace poco, constituidos exclusivamente ..

Middle Miocene vertebrates from the Amazonian Madre de Dios Subandean Zone, Perú

A new middle Miocene vertebrate fauna from Peruvian Amazonia is described. It yields the marsupials Sipalocyon sp. (Hathliacynidae) and Marmosa (Micoureus) cf. laventica (Didelphidae), as well as an unidentified glyptodontine xenarthran and the rodents Guiomys sp. (Caviidae), “Scleromys” sp., cf. quadrangulatus-schurmanni-colombianus (Dinomyidae), an unidentified acaremyid, and cf. Microsteiromys sp. (Erethizontidae). Apatite Fission Track provides a detrital age (17.1 +- 2.4 Ma) for the locality, slightly older than its inferred biochronological age (Colloncuran-early Laventan South American Land Mammal Ages: ~15.6e13.0 Ma). Put together, both the mammalian assemblage and lithology of the fossil-bearing level point to a mixture of tropical rainforest environment and more open habitats under a monsoonal-like tropical climate. The fully fluvial origin of the concerned sedimentary sequence suggests that the Amazonian Madre de Dios Subandean Zone was not part of the Pebas mega-wetland System by middle Miocene times. This new assemblage seems to reveal a previously undocumented “spatiotemporal transition” between the late early Miocene assemblages from high latitudes (Patagonia and Southern Chile) and the late middle Miocene faunas of low latitudes (Colombia, Perú, Venezuela, and ?Brazil)

Estudio del sector agroindustrial derivado de la agricultura en el Departamento Del Magdalena

El presente documento se constituye en la primera visión descriptiva que se tiene del sector Agroindustrial del Magdalena. se identifica y define la problemática del entorno Agroindustrial del Magdalena; igualmente se dio relevancia a los factores que limitan el desarrollo del subsector en referencia. Donde se pretende revelar la situación estructural del mismo, profundizando más en la cualitativo que en lo cuantitativo. razón a que consideramos importante destacar las variables problemas, casi nunca relacionadas en estudios de este tipo