135 research outputs found

    Stratigraphy, structure and geodynamic evolution of the Paleozoic rocks in the Cordillera del Viento (37º S latitude, Andes of Neuquén, Argentina)

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    The Pre-Andean Paleozoic substrate from the Cordillera del Viento anticline is a polyorogenic basement composed of two groups of preorogenic rocks with different stratigraphy and deformation. The oldest set consists of pre-Late Devonian metasedimentary rocks belong­ing to the Guaraco Norte Formation. The upper set is formed by the thick volcano-sedimentary sequence of the Carboniferous Andacollo Group. This group is composed from bottom to top of the silicic volcanic rocks of the Arroyo del Torreón Formation (early Carboniferous) and the marine sedimentary rocks of the Huaraco Formation (late Carboniferous) developed in an extensional basin. Both formations are locally separated by minor syn-extensional unconformities. The relationship between the metamorphic rocks of the Guaraco Norte Formation and the volcano-sedimentary sequence of the Anda­collo Group is not observed, but we inferred a major angular unconformity associated with the Late Devonian-early Carboniferous Chanic orogeny. The main Chanic structures are tight vertical and subvertical folds with slight W-WSW vergence, formed under low-grade meta­morphic conditions, with the development of a pervasive axial-plane cleavage (S1), affected by a disjunctive crenulation cleavage (S2). In the early Permian, during the San Rafael orogeny of the Gondwanan orogenic cycle, deformation occurred under very low-grade to non-metamorphic conditions. The main structures are thrusts and associated folds that are re-folded by the Cordillera del Viento anticline, related to the Andean orogeny. The WNW-oriented and SSW-vergent folds are associated with an incipient axial-plane cleavage in the pyroclastic rocks and pencil lineation in shales. The pre-Andean Paleozoic basement rocks are intruded and unconformably covered by early Permian to Early Triassic? granitoids and silicic volcanic rocks from the Huingancó volcanic-plutonic Complex (equivalent to the Choiyoi Group), establishing the beginning of the Andean orogenic cycle in this region.El sustrato paleozoico pre-andino que aflora en el anticlinal de la Cordillera del Viento, es un basamento poliorogénico que está com­puesto por dos conjuntos de rocas preorogénicas con estratigrafía y condiciones de deformación diferentes. El más antiguo tiene una edad devónica superior y está formado por las rocas metasedimentarias de la Formación Guaraco Norte, en tanto que el conjunto superior son las espesas acumulaciones volcano-sedimentarias carboníferas del Grupo Andacollo. Este grupo, integrado en su parte inferior por rocas volcánicas silíceas de la Formación Arroyo del Torreón (Carbonífero inferior) y hacia techo, por las sedimentitas clásticas marinas de la Formación Huaraco (Carbonífero superior) fue desarrollado en el marco de una cuenca extensional y pueden estar separadas localmente por discordancias menores de carácter sin-extensional. Las relaciones entre las rocas metamórficas y la secuencia volcano-sedimentaria del Carbonífero no se observan, pero se infiere una discordancia mayor asociada con la orogenia Chánica, que tuvo lugar entre el Devónico Superior y el Carbonífero inferior. Las estructuras chánicas están asociadas a un metamorfismo de bajo grado y son pliegues apretados sub-verticales a verticales y con ligera vergencia al O-OSO que llevan asociados un clivaje penetrativo (S1) de rumbo N-S a NNO que está afectado por un clivaje subvertical más espaciado (S2). En el Pérmico inferior, durante la orogenia San Rafael del ciclo orogénico Gondwánico, la deformación contraccional se produce en condiciones de metamorfismo de muy bajo grado o en ausencia de éste. Las estructuras principales son cabalgamientos y pliegues asociados que se encuentran plegados por el anticlinal ándico de la Cordillera del Viento. Los pliegues de rumbo ONO y vergencia al SSO llevan asociados un incipiente clivaje de plano axial en los contactos entre limolitas y volcanitas y lineación de tipo lápiz (pencil) en las lutitas. Las rocas del basamento paleozoico pre-ándico están intruidas y cubiertas discordantemente por rocas volcánicas silíceas de edad Pér­mico inferior a Triásico Inferior?, correspondientes al Complejo volcánico-plutónico Huingancó (equivalente al Grupo Choiyoi), unidad que marca el comienzo el ciclo orogénico Andino, en esta región

    How did Conifers grow in Mesozoic times? : A Jurassic case of growth architecture in Araucariaceae from the La Matilde Formation, Patagonia, Argentina

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    The architecture of a plant represents the expression of the equilibrium between endogenous growth processes and environmental constraints. Simple morphological traits are used to describe a tree's architecture: the growth and branching process, the morphological differentiation of axes, and the position of reproductive structures. The purpose of this contribution is to describe the growth architecture of the Jurassic araucarian trees (in organic connection with Araucaria mirabilis (Spegazzini) emend. Calder cones) present at the most basal part of the La Matilde Formation in the locality of Monumento Natural Bosques Petrificados, Santa Cruz province, Argentina, and to compare them with extant Araucariaceae. Both young and adult specimens had three branching categories from trunk (TA1) to branchlets (A3), corresponding to the typical pattern in extant Araucariaceae. The main, orthotropic stem (TA1) had rhythmic growth and branching, bearing plagiotropic branches in pseudowhorls. Main branches (A2) had rhythmic branching with A3 in two orthostichies. Female cones were terminal at the tip of peduncles, lateral in position with respect to A2 branches, peduncles had a position equivalent to A3 branches. Reiteration patterns are present: total reiterations (bifurcated trunks and big orthotropic branches in trunks with normal plagiotropic branches) and partial reiterations (epicormic branching). Two architectural "morphotypes" were recognized: the "Araucarioid morphotype or morphotype A" includes most of the studied specimens; showing pseudowhorls of plagiotropic branches and reiteration evidences; these characters correspond to Massart's model. "Morphotype B" was observed in bigger trunks, with clearly orthotropic branches irregularly arranged, and no reiteration evidences; they could represent Attim's model. Reiteration patterns are described for the first time for Jurassic gondwanic conifers, in agreement with observations made in Triassic conifers from Arizona and Jurassic conifers from the United Kingdon. Moreover, we can follow Massart's model from some Upper Palaeozoic Walchiaceae to the Mesozoic Araucariaceae studied in this contribution.Sesiones libres.Facultad de Ciencias Naturales y Muse

    The impact of chorionicity on pregnancy outcome and neurodevelopment at 2 years old among twins born preterm: the EPIPAGE-2 cohort study

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    OBJECTIVE To compare the short‐ and mid‐term outcomes of preterm twins by chorionicity of pregnancy. DESIGN Prospective nationwide population‐based EPIPAGE‐2 cohort study. SETTING 546 maternity units in France, between March and December 2011. POPULATION A total of 1700 twin neonates born between 24 and 34 weeks of gestation. METHODS The association of chorionicity with outcomes was analysed using multivariate regression models. MAIN OUTCOME MEASURES First, survival at 2‐year corrected age with or without neurosensory impairment, and second, perinatal, short‐, and mid‐term outcomes (survival at discharge, survival at discharge without severe morbidity) were described and compared by chorionicity. RESULTS In the EPIPAGE 2 cohort, 1700 preterm births were included (850 twin pregnancies). In all, 1220 (71.8%) were from dichorionic (DC) pregnancies and 480 from monochorionic (MC) pregnancies. MC pregnancies had three times more medical terminations than DC pregnancies (1.67 versus 0.51%, P < 0.001), whereas there were three times more stillbirths in MC than in DC pregnancies (10.09 versus 3.78%, P < 0.001). Both twins were alive at birth in 86.6% of DC pregnancies compared with 80.0% among MC pregnancies (P = 0.008). No significant difference according to chorionicity was found regarding neonatal deaths and morbidities. Likewise, for children born earlier than 32 weeks, the 2‐year follow‐up neurodevelopmental results were not significantly different between DC and MC twins. CONCLUSIONS This study confirms that MC pregnancies have a higher risk of adverse outcomes. However, the outcomes among preterm twins admitted to neonatal intensive care units are similar irrespective of chorionicity

    PROCESOS BIOESTRATINÓMICOS ACTUANTES EN KATEPENSAURUS GOICOECHEAI: ANÁLISIS DE FACTORES INTRÍNSECOS Y EXTRÍNSECOS. FORMACIÓN BAJO BARREAL (CRETÁCICO SUPERIOR), PATAGONIA, ARGENTINA

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    Se analizan los factores intrínsecos y extrínsecos que controlaron la preservación del saurópodo rebaquisáurido Katepensaurus goicoecheai, procedente de la Formación Bajo Barreal (Grupo Chubut-Cretácico Superior) en el centro-sur de Chubut, cuenca del Golfo San Jorge, Patagonia central, Argentina. Los restos se preservaron en un depósito de desbordamiento no canalizado, de geometría lobulada, de 30 cm de potencia y vinculado a canales fluviales arenosos. Litológicamente está integrado por areniscas gruesas con abundante matriz pelítica y tobácea, que permiten caracterizarlo como un flujo hiperconcentrado. Los elementos recuperados, que corresponden principalmente al esqueleto axial, yacían sobre depósitos pelíticos de una planicie de inundación distal mal drenada y fueron parcialmente cubiertos por el lóbulo de desbordamiento, quedando estructuras expuestas que fueron intensamente erosionadas. Los restos se encontraron incompletos, desarticulados y exhibiendo evidencias de una exposición subaérea prolongada. Fueron poco movilizados por procesos hidráulicos y reorientados de forma normal a la dirección del desbordamiento. La dispersión lateral muestra grupos de huesos producto de entrampamientos hidráulicos causados por los restos de mayor tamaño en la parte central del lóbulo y los más pequeños hacia los laterales acorde a la distribución de energía del depósito. La escasa potencia del desbordamiento no sepultó completamente los restos. Finalmente, un nuevo desbordamiento cubrió completamente los materiales. La acumulación de huesos de Katepensaurus sería una concentración ósea residual y representa una acumulación parautóctona de origen sedimentológico

    Mobile Manipulation Hackathon: Moving into Real World Applications

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    The Mobile Manipulation Hackathon was held in late 2018 during the IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) to showcase the latest applications of wheeled robotic manipulators. The challenge had an open format, where teams developed an application using simulation tools and integrated it into a robotic platform. This article presents the competition and analyzes the results, with information gathered during the event and from a survey circulated among the finalist teams. We provide an overview of the mobile manipulation field, identify key areas required for further development to facilitate the implementation of mobile manipulators in real applications, and discuss ideas about how to structure future hackathon-style competitions to enhance their impact on the scientific and industrial communities.Peer ReviewedPostprint (published version

    Microwave sensor system for continuous monitoring of adhesive curing processes

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    A microwave sensor system has been developed for monitoring adhesive curing processes. The system provides continuous, real-time information about the curing progress without interfering with the reaction. An open-coaxial resonator is used as the sensor head, and measurements of its resonance frequency and quality factor are performed during cure to follow the reaction progress. Additionally, the system provides other interesting parameters such as reaction rate or cure time. The adhesive dielectric properties can also be computed off-line, which gives additional information about the process. The results given by the system correlate very well with conventional measurement techniques such as differential scanning calorimetry, combining accuracy and rate with simplicity and an affordable cost. © 2012 IOP Publishing Ltd.The authors thank Rut Benavente Martinez for her assistance in the DSC experiments. The contract of BG-B is financed by the Ministry of Science and Innovation of Spain, through the 'Torres Quevedo' Sub-programme, which is also co-financed by the European Social Fund (ESF). This work has been financed by the Ministry of Science and Innovation of Spain through the project MONIDIEL (TEC2008-04109).García Baños, B.; Catalá Civera, JM.; Penaranda-Foix, FL.; Canós Marín, AJ.; Sahuquillo Navarro, O. (2012). Microwave sensor system for continuous monitoring of adhesive curing processes. Measurement Science and Technology. 23(3). https://doi.org/10.1088/0957-0233/23/3/035101S233Jost, M., & Sernek, M. (2008). Shear strength development of the phenol–formaldehyde adhesive bond during cure. Wood Science and Technology, 43(1-2), 153-166. doi:10.1007/s00226-008-0217-2Costa, M. L., Botelho, E. C., Paiva, J. M. F. de, & Rezende, M. C. (2005). Characterization of cure of carbon/epoxy prepreg used in aerospace field. 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    Image-guided ToF depth upsampling: a survey

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    Recently, there has been remarkable growth of interest in the development and applications of time-of-flight (ToF) depth cameras. Despite the permanent improvement of their characteristics, the practical applicability of ToF cameras is still limited by low resolution and quality of depth measurements. This has motivated many researchers to combine ToF cameras with other sensors in order to enhance and upsample depth images. In this paper, we review the approaches that couple ToF depth images with high-resolution optical images. Other classes of upsampling methods are also briefly discussed. Finally, we provide an overview of performance evaluation tests presented in the related studies

    Stratigraphy, structure and geodynamic evolution of the Paleozoic rocks in the Cordillera del Viento (37º S latitude, Andes of Neuquén, Argentina)

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    The Pre-Andean Paleozoic substrate from the Cordillera del Viento anticline is a polyorogenic basement composed of two groups of preorogenic rocks with different stratigraphy and deformation. The oldest set consists of pre-Late Devonian metasedimentary rocks belonging to the Guaraco Norte Formation. The upper set is formed by the thick volcano-sedimentary sequence of the Carboniferous Andacollo Group. This group is composed from bottom to top of the silicic volcanic rocks of the Arroyo del Torreón Formation (early Carboniferous) and the marine sedimentary rocks of the Huaraco Formation (late Carboniferous) developed in an extensional basin. Both formations are locally separated by minor syn-extensional unconformities. The relationship between the metamorphic rocks of the Guaraco Norte Formation and the volcano-sedimentary sequence of the Andacollo Group is not observed, but we inferred a major angular unconformity associated with the Late Devonian-early Carboniferous Chanic orogeny. The main Chanic structures are tight vertical and subvertical folds with slight W-WSW vergence, formed under low-grade metamorphic conditions, with the development of a pervasive axial-plane cleavage (S1), affected by a disjunctive crenulation cleavage (S2). In the early Permian, during the San Rafael orogeny of the Gondwanan orogenic cycle, deformation occurred under very low-grade to non-metamorphic conditions. The main structures are thrusts and associated folds that are re-folded by the Cordillera del Viento anticline, related to the Andean orogeny. The WNW-oriented and SSW-vergent folds are associated with an incipient axial-plane cleavage in the pyroclastic rocks and pencil lineation in shales. The pre-Andean Paleozoic basement rocks are intruded and unconformably covered by early Permian to Early Triassic? granitoids and silicic volcanic rocks from the Huingancó volcanic-plutonic Complex (equivalent to the Choiyoi Group), establishing the beginning of the Andean orogenic cycle in this region.Fil: Giacosa, Raul Eduardo. Secretaría de Industria y Minería. Servicio Geologico Minero Argentino; Argentina. Universidad Nacional de Rio Negro; ArgentinaFil: Allard, Jose Oscar. Universidad Nacional de la Patagonia; ArgentinaFil: Foix, Nicolas. Universidad Nacional de la Patagonia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Heredia, N.. Instituto Geológico y Minero de España; Españ
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