Sedimentology, Ichnology and Sequence Stratigraphy of Black Shales from the Upper Jurassic - Lower Cretaceous Vaca Muerta Formation, Neuquén Basin, Argentina

During the past decades, the study of fine-grained successions has received considerable attention, mainly due to the groundbreaking work of various mudstone sedimentologists who suggested bottom transport processes as plausible mechanisms for mud sedimentation. Moreover, an increased interest has been growing due to the extensive development of unconventional shale reservoirs in USA. In this context, the Upper Jurassic-Lower Cretaceous Vaca Muerta Formation from the Neuquén Basin, Argentina, stands as a valuable shale reservoir for both industry and academic research that can be used to expand our knowledge on ancient fine-grained, organic-rich depositional environments. This Formation is the most important unconventional shale reservoir in South America, with exceptional characteristics for oil and gas extraction. It is well exposed in central western Argentina and contains a fair amount of core data that can be used to evaluate sedimentary processes and trace fossils. The present study analyzed sedimentologic, ichnologic and sequence stratigraphic datasets of the Vaca Muerta Formation to construct a robust depositional model and compare the results with other studies in order to test previous models and propose new ideas. For this purpose, outcrops from a basin margin location (Picún Leufú area), as well as outcrops (Yesera del Tromen) and cores (wells 1 to 9) from the basin centre (where most of the unconventional development is currently active), were analyzed in detail. In the basin margin location (Picún Leufú area), ten sections were logged in the Kimmeridgian to Tithonian succession. The interval encompasses two third-order sequences formed in continental environments and a mixed carbonate-siliciclastic, shelf-margin clinoform system. At the base, the Quebrada del Sapo Formation represents sandstone, conglomerate and mudstone of eolian and fluvial origin. On top, marine carbonaceous, mixed to calcareous mudstone and sandstone of the Vaca Muerta (bottomset and foreset of the clinoform) and Picún Leufú (topset) formations occur. At the base, the clinoform system consists of a thin, retrograding, open bay facies association comprising beach, bay margin, proximal bay and distal bay facies. Above, a siliciclastic basin facies association is constituted by basin, hyperpycnal lobe, lobe fringe, channel-fill complex and overbank facies, developed at the bottomset of the clinoform system. In the foreset and topset, slope mud belt, mixed slope, slope sand bodies, sandy shoal, sand bar complex and lagoonal facies are part of the foreset facies association. This analysis challenged the previous paradigm of a catastrophic transgression at the onset of deposition of the Vaca Muerta Formation. Catastrophic rates of sea-level rise (metres per day) are incompatible with the existence of a basal, retrograding, marginal marine succession suggesting a transition between continental and marine facies. A comparison to modern analogues of marine flooding over dunes indicates that rates of sea-level rise similar to Holocene ones (mm to cm per year) are plausible and may have generated a rapid, yet not catastrophic transgression. Hence, rapid transgressions represent an alternative to “catastrophic” and “normal” scenarios of marine flooding over eolian deposits. The Late Jurassic represents a non-glacial time, and the global sea-level maximum highstand pre-dated the Vaca Muerta transgressive event, indicating that part of the sea-level rise has to be attributed to tectonic/thermal subsidence and compaction. In addition, the combined analysis provides insights into sedimentary processes affecting bottomset and foreset of a fine-grained clinoform system, highlighting the role of wave-influenced hyperpycnal flows associated with higher fluvial input in Picún Leufú and their effect on diluting organic matter content. In the basin centre (Yesera del Tromen and cores from wells 1 to 9), the succession was represented by the Tithonian to Valanginian, mixed carbonate-siliciclastic, shelf-margin clinoform system of the Vaca Muerta (bottomset and foreset) and Quintuco (topset) formations. The succession mostly comprises mixed to calcareous mudstone and bioclastic to intraclastic wackestone developed in four third-order sequences (Sequence 1 to 4). Sequence 1 and 2 start with a transgressive, marginal marine facies association comprising beach and open bay facies. Above, the bottomset and lower foreset of the clinoform shows starved, anoxic, dysoxic and oxic basin facies grouped into the basin facies association, and crinoid-rich, bioclastic- and silt-rich drift, and mixed drift and fluid mud facies, included in the drift facies associations. In the foreset, distal, mid, proximal, and fluid mud-rich slope facies occur as part of the slope facies associations. The slope association evolves from dominantly hemipelagic facies in the older, low-angle clinoforms, to mostly fluid mud-rich slope facies due to higher foreset angles in younger clinoforms. Sequence 3 and 4 are poorly cored, yet low- and high-energy outer ramp facies of the outer ramp facies association with subordinate basin and slope facies associations can be observed. This analysis provides several insights into the understanding of the Vaca Muerta Formation and other ancient fine-grained depositional environments. First, climate and consequent basin circulation were found to control sediment partitioning along the clinoform. Warmer climates triggered equatorward migration of the arid belt, humid conditions and estuarine circulation, producing high TOC and siliciclastic content due to anoxia and enhanced riverine input, respectively. In contrast, cooler climates associated with a poleward migration of the arid belt generated arid conditions and anti-estuarine or weakened estuarine circulation, triggering intense contour currents at deep waters. Low TOC and high carbonate content is recorded, due to high burndown of organic matter under upper dysoxic to oxic conditions, and enhanced shelf export of carbonate sediments by cascading. Organic matter content was sourced from the water column (pelagic), indicating that bottom currents and sediment-gravity flows dilute the TOC content of these deposits. Second, the trace-fossil analysis shows an ichnofauna differing from the classic Chondrites and Zoophycos ichnoguild recorded in organic-rich mudstone successions. In contrast, cryptobioturbation, pellet-rich ichnocoenoses, and biodeformational structures are abundant in this formation. This characteristic can be explained by bioturbation in a food-rich benthic environment, which precluded specialized feeding and the development of tiered communities. Limited oxygenation is deemed responsible for reduced bioturbation index, penetration depth, burrow size, and ichnodiversity. Moreover, biodeformational structures in mudstone are associated with soupy to very soft substrates, whereas a change to soft and stiffgrounds during ash deposition enhanced preservation of discrete trace fossils. This last relationship indicates that tuff deposits and rock fabric can be used to evaluate bioturbation in homogeneous, fine-grained successions in order to claim biogenicity of structures or delineate bottom water oxygenation. Finally, the characteristics of this Formation (low bioturbation intensity due to oxygen deficiency and low foreset angles hampering gravity flow transport) allowed the delineation of contourite deposits. Contourite deposits (drifts) can be differentiated from sediment-gravity flow deposits by their evidence of long-term transport, low sediment concentration, and long-term oxygen introduction at the sea-floor. Furthermore, contourites are host to a particular trace-fossil assemblage that was controlled by food (deposited at the surface or in suspension), oxygenation (increasing oxygen levels), hydrodynamic energy (precluding biogenic reworking during higher energy events) and water turbidity (allowing suspension feeding). The basin-wide increase in oxygenation generated by contourites indicates that these were produced by a wind- and thermohaline-driven circulation system of deep waters that was intensified during arid and cooler climates, which were times of enhanced cascading of dense, shelf waters. The trace fossil data supports the existence of high bioturbation intensity in contourite deposits, yet indicate that sedimentary structures can be preserved in muddy contourites when different stress factors are combined

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Sin resume

Ampliación del área de distribución de Liolaemus cazianae (Lobo, Slodky y Valdecantos, 2010) en la Provincia de Salta (Argentina)

Liolaemus cazianae es una especie recientemente descrita (Lobo et al., 2010) que habita en gran parte de la puna de la provincia de Salta. Los datos de distribución conocidos de Liolaemus cazianae eran los aportados en su descripción formal (Lobo et al., 2010): Suroeste de la región del Salar de Arizaro (Departamento Los Andes, Provincia de Salta, Argentina), abarcando un área aproximada de 40 por 15 km, situada en un rango altitudinal que varia entre 3500 y 4300 m s.n.m. En este trabajo se aporta información que extiende el área de distribución de L. cazianae a 125 km al noreste de la localidad original en las proximidades de Cauchari y además se incluyen registros Saltade menores distancias a la conocida en sitios vecinos como Los Colorados (76 km), sitio a 10 km al oeste de Tolar Grande (62 km), Ojo de Mar (58 km) y Cuesta de Caipe camino a Socompa (45 km) (Fig. 1).Fil: Paz, Marcos Maximiliano. Fundación Miguel Lillo. Dirección de Zoología. Instituto de Herpetologia; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina;Fil: Semhan, Romina Valeria. Fundación Miguel Lillo. Dirección de Zoología. Instituto de Herpetologia; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina;Fil: Abdala, Cristian Simón. Fundación Miguel Lillo. Dirección de Zoología. Instituto de Herpetologia; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

New Liolaemus (Iguania: Liolaemidae) with a new morphological character from the border between Argentina and Chile.

Liolaemus belongs to the Eulaemus subgenus, that is included in the Liolaemus montanus group or section, and is distributed in Argentina, Bolivia, Chile and Peru. The species members of this clade inhabit arid and high altitude environments, usually above 2 800m, and have a strong tendency to herbivory and a viviparous reproductive type. In a herpetological expedition to the Salta Province highlands, Argentina, in April 2012, we collected individuals of this new species for their description. The specimens were collected with loop, slaughtered by anesthesia and deposited in the herpetological collection of Fundación Miguel Lillo in Tucumán (FML). To characterize this new taxon, we analyzed 144 external morphological characters, referring primarily to lepidosis, color pattern, and body proportions, comparing with data from 66 constituent species of the L. montanus group (45 taxa from collection specimens and 21 from literature). Description of the colors in life was made in the field and based on photographs taken during the capture. The species described in this work inhabits a very narrow mountain range area in Salta Province (Argentina), and the Atacama Region (Chile), always above the 3 600m. This new taxon shows characteristics of lepidosis and color patterns clearly different from the other species members of the L. montanus group: the maximum snout-vent length is 72.9mm; shows 74-96 scales around midbody, 89-104 dorsal scales between the occiput and hind limbs, 92-109 ventrals, precloacal pores are evident in both, males and females, and supernumerary pores in males. Also, the presence of postcloacal pores stands out as unique among all Liolaemus. This is a new character, not only for the genus, but also to all Reptilia, becoming a morphological discovery of great importance, since in reptiles only precloacal and femoral pores are known. Based on our field observations, this new Liolaemus is related to rocky environments, which are used as refuge by this omnivorous species, and when handled, very aggressive males.Fil: Abdala, Cristian Simón. Fundación Miguel Lillo. Dirección de Zoología. Instituto de Herpetología; Argentina; Consejo Nacional de Investigaciones Científico y Técnicas. Centro Científico Tecnológico - CONICET - Tucumán. Unidad Ejecutora Lillo; Argentina;Fil: Paz , Marcos Maximiliano. Fundación Miguel Lillo. Dirección de Zoología. Instituto de Herpetología; Argentina; Consejo Nacional de Investigaciones Científico y Técnicas. Centro Científico Tecnológico - CONICET - Tucumán. Unidad Ejecutora Lillo; Argentina;Fil: Semhan, Romina Valeria. Fundación Miguel Lillo. Dirección de Zoología. Instituto de Herpetología; Argentina; Consejo Nacional de Investigaciones Científico y Técnicas. Centro Científico Tecnológico - CONICET - Tucumán. Unidad Ejecutora Lillo; Argentina

Responsabilidad civil médica por omisión en las instituciones prestadoras de servicios de salud (IPRESS) en el Estado Peruano

La investigación parte del Problema: ¿Qué tipo de responsabilidad civil debe aplicarse para los eventos dañosos que provienen de la actividad médica en las IPRESS en el Estado peruano?; siendo el Objetivo: Analizar el tipo de responsabilidad civil que debe aplicarse para los eventos dañosos que provienen de la actividad médica en las IPRESS en el Estado peruano. La Investigación se ubica dentro del Tipo Explicativo; en el Nivel comprensivo; Se utilizará para contrastar la Hipótesis, los Métodos: hermenéutico, exegético y sistemático: Con un Diseño no experimental y transaccional. Para la Recolección de Información se utilizará las fichas textuales y de resumen respecto a documentos referidos a leyes, doctrina y jurisprudencia sobre Eventos dañosos en la actividad médica y Responsabilidad Civil; llegándose a la conclusión de que es imprescindible desarrollar un catálogo de supuestos de responsabilidad civil objetiva y subjetiva en los daños de la actividad médica

El rol y el alcance de la medición en la simulación astronómica

El concepto de medición se halla sujeto a una cierta tensión originada por estos dos ámbitos dentro de la práctica científica. El objetivo del presente trabajo consiste en mostrar el alcance que poseen las mediciones logradas- a partir de las simulaciones computacionales con respecto a aquellas obtemdas medIante la observación tradicional

Primer registro de Mesocestoides sp. (Ciclophyllidea: Cestoda) en dos hembras de Diplolaemus leopardinus (Werner, 1898)

El parasitismo interno en lagartos, es causado frecuentemente por nematodos, pentastómidos y cestodos (Criscione y Font, 2001; Bursey et al. 2010; McAllister et al. 2011). Entre los cestodos, los Ciclophyllidea constituyen un grupo que afecta principalmente a reptiles y que se caracterizan por causar enfermedades de importancia veterinaria (Schneller y Pantchev, 2008). En este Orden se encuentra el Género Mesocestoides (Vaillant 1863), compuesto por gusanos planos, habitantes del tracto intestinal y ocasionalmente de las cavidades peritoneales. Presenta un ciclo de vida trifásico con formas cirticercoide, tetratiridio y metacestoides (Chervy, 2002). Los hospedadores primarios son artrópodos (Formícidos, coleópteros, ácaros) que ingieren huevos de las heces del hospedador definitivo. El hospedador secundario incorpora los cirticercoides al alimentarse, los cuales se desarrollan en tetratiridios capaces de invadir la cavidad peritoneal del hospedador. El ciclo se completa cuando el parásito alcanza al hospedador definitivo al consumir este, pequeños vertebrados infectados. Es en esta etapa donde se desarrolla finalmente, la forma sexual adulta. Los hospedadores definitivos son por lo general mamíferos carnívoros (Canidae, Felidae) y marsupiales (Didelphidae) (Richardson y Campo, 2005; Gallas y Fraga da Silveira, 2011), no obstante, también han sido encontrados en lagartos (Criscione y Font, 2001; Martin y Roca, 2004, 2005; Gürelli et al., 2007; Mcallister et al., 2011; Yildirimhan et al., 2011). La ocurrencia de tetratiridios de Mesocestoides en iguánidos es más común en América del norte (Conn y Etges 1984; McAllister, 1988; Mcallister et al., 1992; Goldberg et al., 1995; 2003). Por otro lado, se registró la presencia de tetratiridios en Anolis transversalis al Norte de Brasil, siendo hasta el momento el único registro existente del género Mesocesotoides para lagartos de América del Sur (Goldberg et al., 2006; Ávila y Silva, 2010).Fil: García, Noelia Elizabeth. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales E Instituto Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ruiz Monachesi, Mario Ricardo. Fundación Miguel Lillo. Dirección de Zoología. Instituto de Herpetología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Paz, Marcos Maximiliano. Fundación Miguel Lillo. Dirección de Zoología. Instituto de Herpetología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Geographic distribution: Liolaemus tirantii

Departamento El Cuy: El Chocón (39.51250°S, 68.57583°W; WGS 84). 20 October2008. C. S. Abdala and G. J. Scrocchi. Verified by S. Quinteros. Museo Patagónico de Ciencias Naturales Juan Carlos Salgado, General Roca, Rio Negro, Argentina (MPCN-H 30). Cerro Policía, Puesto Yapeleo, 15 km N of Cerro Policía, El Barrial (39.64608°S, 68.78367°W; WGS 84), 474 m elev. 16 November 2015. C. S.Abdala, R. V. Semhan, M. M. Paz, and A. L. Bulacios Arroyo. Verified by S. Quinteros. Herpetological Collection Fundación Miguel Lillo, San Miguel de Tucumán, Tucumán, Argentina (FML 29722?29730). Specimens were active, sunning and feeding from 1000?1800 h in a region with greyish to brownish sandy soils.First province records, extending the known distribution 100 km SE from a previous record near pueblo La Amarga, Zapala Departament, Neuquén, Argentina (Avila et al. 2017. Zootaxa 4362:535?563). Project registered at Dirección de Fauna Silvestre de Río Negro (Exp. 085558-SAyDS-2015). The fieldwork wassupported by PICT 2263 and 1398, Agency for Scientific and Technological Promotion.Fil: Bulacios Arroyo, Ana Lucia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Semhan, Romina Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Paz, Marcos Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Abdala, Cristian Simón. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentin

Descripción y correlación del estado nutricional en escolares de 8 a 10 años pertenecientes al establecimientos Educacional Munipalizado "Escuela Carlos Hernández Peña" de la comuna de Peñalolén , Región Metropolitana, Chile 2014

Tesis (Licenciatura en Kinesiología)Objetivo: Describir el estado nutricional y correlacionar el IMC y CC de niños de 3° y 4° básico, pertenecientes al colegio municipal “Escuela Carlos Hernández Peña” de la comuna de Peñalolén de la ciudad de Santiago, Chile. Método: Esta investigación corresponde a un estudio de diseño descriptivo de correlación y corte transversal. La población total evaluada en este estudio fue de 68 alumnos de ambos sexos, entre 8 y 10 años, 11 meses y 30 días de edad. La medición del IMC se hizo mediante una Balanza mecánica SECA®, (estatura y el peso del niño/a) y el CC con una cinta métrica inextensible marca Dynatronics. Además, se evaluó el consumo de frutas y verduras de los niños/as a través de 2 preguntas extraídas del módulo Dieta de la ENS 2009-2010. Se utilizó el programa Microsoft Excel® 2010 para el análisis de los resultados. Resultados: La mayoría de los alumnos evaluados presentó un IMC normal, siendo las niñas las que obtuvieron mayor IMC en comparación a los hombres. La CC de las niñas que se encontraban en el p90 superó el punto de corte de las mujeres adultas. En cuanto a la correlación entre estos términos hay asociación directa con un valor de 0,86 y un nivel de significancia p<0,05. En general los alumnos presentan un mayor consumo de verduras que de frutas.Objective: Describe the nutritional status and correlate the Body Mass Index (BMI) and Waist Circumference (WC) of children from 3rd and 4th grade enrolled in the municipal school “Carlos Hernandez Peña” from the commune of Peñalolen in the city of Santiago of Chile. Method: This survey consists in a correlated descriptive cross-sectional study. The total population evaluated in this study was 68 students from both genres, between 8 and 10 years old, eleven months and 30 days. The measurement of the BMI was made with a weighing scale SECA (height and weight of boy/girl) and the WC with a Dynatroics measuring tape. Additionally, intake of vegetable and fruit was also evaluated through two questions taken from the National Health Survey (NHS) 2009-2010 diet module. Microsoft Excell 2010 program was used to analyze the results of the survey. Results: The majority of the students evaluated showed a normal BMI, but the girls were the ones who rated higher BMI than boys. The WC of the girls who were in the percentile 90 exceeded the cut-off point of women. As regards the correlation between these terms there is a direct association with a value of 0,86 and a significance level of p<0,05. In general the students show a higher consumption of vegetables than fruit