Sedimentation, earthquakes, and tsunamis in a shallow, muddy epeiric sea: Grinnell Formation (Belt Supergroup, ca. 1.45 Ga), western North America

Interpreting the deposits of ancient epeiric seas presents unique challenges because of the lack of direct modern analogs. Whereas many such seas were tectonically relatively quiescent, and successions are comparatively thin and punctuated by numerous sedimentary breaks, the Mesoproterozoic Belt Basin of western North America was structurally active and experienced dramatic and continuous subsidence and sediment accumulation. The Grinnell Formation (ca. 1.45 Ga) in the lower part of the Belt Supergroup affords an opportunity to explore the interplay between sedimentation and syndepositional tectonics in a low-energy, lake-like setting. The formation is a thick, vivid, red- to maroon-colored mudstone-dominated unit that crops out in northwestern Montana and adjacent southwestern Alberta, Canada. The mudstone, or argillite, consists of laminated siltstone and claystone, with normal grading, local lowamplitude, short-wavelength symmetrical ripples, and intercalations of thin tabular intraclasts. These intraclasts suggest that the muds acquired a degree of stiffness on the seafloor. Halite crystal molds and casts are present sporadically on bedding surfaces. Beds are pervasively cut by mudcracks exhibiting a wide variety of patterns in plan view, ranging from polygonal to linear to spindle-shaped. These vertical to subvertical cracks are filled with upward-injected mud and small claystone intraclasts. Variably interbedded are individual, bundled, or amalgamated, thin to medium beds of white, cross-laminated, medium- to coarse-grained sandstone, or quartzite. These are composed of rounded quartz grains, typically with subangular to rounded mudstone intraclasts. Either or both the bottoms and tops of sandstone beds commonly show sandstone dikes indicative of downward and upward injection. Both the mudcracks and the sandstone dikes are seismites, the result of mud shrinkage and sediment injection during earthquakes. An origin via passive desiccation or syneresis is not supported, and there is no evidence that the sediments were deposited on alluvial plains, tidal flats, or playas, as has been universally assumed. Rather, deposition occurred in relatively low-energy conditions at the limit of ambient storm wave base. The halite is not from in situ evaporation but precipitated from hypersaline brines that were concentrated in nearshore areas and flowed into the basin causing temporary density stratification. Sandstone beds are not fluvial. Instead, they consist of allochthonous sediment and record a combination of unidirectional and oscillatory currents. The rounded nature of the sand and irregular stratigraphic distribution of the sandstone intervals are explained not by deltaic influx or as tempestites but as coastal sands delivered from the eastern side of the basin by off-surge from episodic tsunamis generated by normal faulting mainly in the basin center. The sands were commonly reworked by subsequent tsunami onrush, off-surge, seiching, and weak storminduced wave action. Although the Grinnell Formation might appear superficially to have the typical hallmarks of a subaerial mudflat deposit, its attributes in detail reveal that sedimentation and deformation took place in an entirely submerged setting. This is relevant for the deposits of other ancient epeiric seas as well as continental shelves, and it should invite reconsideration of comparable successions.Fil: Pratt, Brian. University of Saskatchewan; CanadáFil: Ponce, Juan Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; Argentin

Tidal signature recorded in burrow fill

The arrangement of sediment couplets preserved in Thalassinoides shafts suggests that tides regulated the passive filling of these trace fossils and, thus, represent tubular tidalites. The thickness variation in individual layers and couplets implies a mixed diurnal, semi-diurnal tidal signature where packages of either thick-layered or thin-layered couplets alternate. Calcarenitic sediment accumulated when tidal current velocity was too high to allow deposition of mud, whereas a marly mud layer is interpreted to have formed during more tranquil times of a tidal cycle (in particular, low-tide slack water). The tidal record within the burrows covers a few weeks and the corresponding spring-neap cycles. The fill of the Thalassinoides shafts is the only known record to decipher the tidal signature from otherwise totally bioturbated sediments. These deposits accumulated in a lower-shoreface to upper-offshore setting during the late Miocene on a shallow shelf extending from the Atlantic Ocean to the west into northern Patagonia. The fill of all investigated burrows started around spring tide and, thus, the behaviour of the burrow producers - probably crustaceans - is speculated to have been affected by tides or the high water level because all studied burrows became abandoned around the same period of a tidal cycle.Fil: Wetzel, Andreas. Universidad de Basilea; SuizaFil: Carmona, Noelia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Universidad Nacional de Río Negro. Sede Alto Valle. Instituto de Investigaciones en Paleobiología y Geología; ArgentinaFil: Ponce, Juan Jose. Universidad Nacional de Río Negro. Sede Alto Valle. Instituto de Investigaciones en Paleobiología y Geología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentin

Biogenic structures of unioniform bivalves in wet-interdune deposits (Late Miocene-early Pliocene, Argentina)

Environmental changes within a Neogene coastal dune system are recorded by endobenthic unioniform bivalves that lived in muddy or sandy interdune pond sediments. These bivalves were suspension-filter feeders that formed dense, almost monospecific communities in the wet-interdune deposits of the continental intervals of the Río Negro Formation (late Miocene-early Pliocene). Activity of unioniform bivalves appears to be related to sediment type; resting and locomotion traces dominate in the muddy heterolithic facies, whereas equilibrium/escape structures prevail in the sand-dominated heterolithic facies. These traces characterize two scenarios of the wet-interdune development. First, during high and/or relatively stable water levels, bivalves colonized the muddy bottom and produced resting and locomotion traces. When water level dropped due to desiccation, biogenic structures were impacted by the formation of mud cracks and subsequently covered by sand delivered by migrating dunes. Second, in spite of dune migration, some interdune areas remained wet or flooded and, in response to sediment aggradation, the bivalves produced equilibrium or escape structures, depending on the thickness of eolian sand cover. Only the integration of ichnologic and sedimentologic observations allows deciphering the evolution of the Neogene wet-interdune system in such a detail.Fil: Carmona, Noelia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Ponce, Juan Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Wetzel, Andreas. Universidad de Basilea; Suiz

Gyrochorte "highways" and their environmental significance in shallow-marine sediments

The reworking of a trace by a subsequently following organism represents a so-called sequorichnial behavior and leads to formation of a “burrowing highway”. Burrowing highways occur more frequently than assumed in the fossil record. Their ichnological and sedimentological meaning is elucidated by using the trace fossil Gyrochorte. Gyrochorte producers exploiting sandy event beds tend to use “burrowing highways” in the same direction. Evidently, the Gyrochorte producers are thigmotactically highly sensitive as they can recognize a burrow produced by the same species because of the less densely packed grains, a somewhat increased mud content, and supposedly mucus segregated within the burrow. These changes make the reworking of pre-existing burrows energetically advantageous. However, in shallow-marine settings mucus is degraded rapidly and loose sediment consolidates in a short while. Therefore, the time to recognize a pre-existing burrow appears to be limited and a rather high number of organisms is a prerequisite for reutilization of a previous trace. “Burrow highways” potentially represent an additional criterion to characterize an opportunistic population strategyFil: Wetzel, Andreas. Universität Basel; SuizaFil: Carmona, Noelia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Negro. Sede Alto Valle. Instituto de Investigaciones en Paleobiología y Geología; ArgentinaFil: Ponce, Juan Jose. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Negro. Sede Alto Valle. Instituto de Investigaciones en Paleobiología y Geología; Argentin

Ansiedad y agresividad en adolescentes de la Institución Educativa "Maria Auxiliadora" de Cercado de Lima, 2022

El presente estudio tuvo como fin determinar la relación significativa entre la ansiedad y la agresividad en los estudiantes de la institución educativa María Auxiliadora, en el cercado de Lima, 2020. El enfoque fue cuantitativo de diseño no experimental, de corte trasversal y de tipo descriptiva, la muestra estuvo compuesta por 138 adolescentes entre 11 y 18 años de edad de ambos sexos y se usaron para los propósitos de la misma, los inventarios de ansiedad de Beck (BAI) y el inventario de agresividad de Buss y Perry. Los resultados arrojaron una correlación de tipo directa positiva y con un grado de significancia moderada (p=0.00; r=0,68), Con respecto a los objetivos específicos se encontró que si existe correlación positiva moderada entre las dimensiones de la ansiedad con la agresividad. Por lo que se concluye que los estudiantes de la institución María Auxiliadora, en cercado de Lima, tienen indicadores de ansiedad y agresividad, también obtuvieron un nivel de ansiedad leve con un 57,2% y una agresividad media de 26% para este estudio

Understanding organic materials performance in field-effect transistors

Comunicación oralIn the last years, much of our effort has been devoted to the search and study of new high-mobility semiconductors for organic thin film transistors. The approach used for the materials design has been two-fold: (i) the combination of donor and acceptor moieties in the pi-conjugated skeleton, which allows fine tuning of the frontier molecular orbitals, being this necessary for achieving electron/hole or ambipolar transport and ambient stability; and (ii) rational selection of the type and positioning of specific solubilizing substituents ensuring processability, which is essential to make these materials scalable to industry. However, material processability should be attained minimizing a negative effect on charge transport. Therefore, proper energy levels, planar molecular conformations, close intermolecular pi-pi stacking and adequate thin film crystallinity need to be maintained upon alkyl substitution. In this communication, several examples of molecular and polymeric materials are shown. A rational design, guided by experimental and theoretical evidences, has prompted modifications on their conjugated skeletons, donor/acceptor subunits ratio and/or selection of proper alkyl solubilizing chains, which induce noticeable changes in their electronic performances. The main aim of these studies is the basic understanding of charge transport in organic materials. For this end, we will use Raman spectroscopy and DFT quantum-chemical calculations as important tools for materials characterization.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Development of arbuscular mycorrhizal fungi in the presence of different patterns of Trifolium repens shoot flavonoids

We tested the effects of the flavonoid 3-methoxi-5,6,7,8-hydroxy-4'hydroxy flavone (NMHTV) isolated from shoots of non arbuscular mycorrhizal (AM) inoculated clover, and of the flavonoids 5,6,7,8-hydroxy-3-methoxy flavone (MH-1); 5,6,7,8-hydroxy-4'- hydroxy flavone (MH-2); and 5,7-hydroxy-3,4'-methoxy flavone (MH-3); isolated from AM clover (Trifolium repens) shoots, on spore germination, hyphal length, hyphal branches and the number of cluster of auxiliary cells or the number of secondary spores (Presymbiotic stage) and on the number of entry points and the percentage of AM colonized root of tomato (Lycopersicum esculentum) by the AM fungi Gigaspora rosea, Giaspora margarita, Glomus mosseae and Glomus intraradices (Symbiotic stage). Non significant effects of the flavonoids isolated from the shoot of mycorrhizal colonized clover on the presymbiotic and symbiotic stages of Gigaspora and Glomus endophytes were found. The flavonoid NMHTV isolated from non AM clover shoot, did not affect the percentage of germination of spores but significantly increased (P < 0.05) the other steps of the presymbiotic stage of Gi. margarita spores when 2 μM concentration was used. The symbiotic stage of Gi. margarita was also significantly increased when 2 μM of the flavonoid NMHTV was applied. This flavonoid had no effect on the presymbiotic development of G. mosseae, G. intraradices and Gi. rosea except when 8 μM concentration was used, which inhibited the hyphal length of Gi. rosea. These results suggest the possible implication of the flavonoid NMHTV in the susceptibility of tomato roots to the AM formation by Gi. margarita. The absence of stimulation of the AM presymbiotic and symbiotic stages in tomato by exogenous application of the newly synthesized flavonoids MH-1, MH-2, and MH-3, in clover shoots after AM colonization, indicated that the autorregulation of the AM symbiosis can be, at least partially, due to the disappearance of flavonoids in AM colonized plants that stimulated the AM symbiosis.Fil: Scervino, Jose Martin. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; ArgentinaFil: Ponce, María Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Della Mónica, Ivana Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Vierheilig, Horst. Universitat Fur Bodenkultur Wien; Austria. Consejo Superior de Investigaciones Científicas. Estación Experimental del Zaidín; EspañaFil: Ocampo, Juan Antonio. Consejo Superior de Investigaciones Científicas. Estación Experimental del Zaidín; EspañaFil: Godeas, Alicia Margarita. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Microbially-induced sedimentary structures (MISS) in the Puerto Rosales tidal flat, Bahía Blanca estuary

El estudio de matas microbianas en ambientes marinos costeros silicoclásticos actuales constituye una importante fuente de información para el análisis de análogos fósiles. En el estuario de Bahía Blanca se estudiaron planicies de marea cubiertas por matas desde un enfoque geobiológico, con el objetivo de identificar y describir estructuras inducidas por actividad microbiana (ESIAM), y distinguir rasgos presentes en los sistemas actuales que permitan reconocer estas comunidades de microorganismos en depósitos fósiles. Se realizaron muestreos biológicos y sedimentológicos, y se implementaron técnicas de microscopía óptica y electrónica para la determinación de microorganismos y la identificación de texturas características y minerales autigénicos. Las matas microbianas resultaron estar dominadas por cianobacterias y, en menor proporción, diatomeas; microorganismos que generan sustancias exopoliméricas que bioestabilizan la superficie sedimentaria. Se reconocieron texturas típicas de matas epibentónicas, tales como granos orientados y granos pequeños unidos por la mata, pirita framboidal y ceolitas. En la zona intermareal-supramareal se identificaron domos de gas, fábrica porosa esponjosa y superficies tipo colador. Además se observaron grietas de contracción, dobleces, fragmentos de mata, depresiones y remanentes erosivos, pliegues y arrugas, así como también ondulitas multidireccionales. Las estructuras halladas están relacionadas con condiciones de calma/latencia, exposición prolongada (desecación) y eventos de tormenta con alta energía erosiva sobre la planicie (olas y corrientes fuertes). En este sentido, las ESIAM resultan importantes indicadoras de condiciones ambientales particulares que presentan un elevado potencial de preservación. Su reconocimiento en el registro fósil, a través de rasgos macro y microscópicos, permiten refinar las interpretaciones paleoambientales en sucesiones marino-costeras.The study of microbial mats in modern siliciclastic coastal marine settings represents an important analogue for the analysis of fossil deposits in similar paleoenvironments. In the Bahía Blanca estuary, mat-covered tidal flats were studied from a geobiological perspective with the aims of identifying and describing microbially-induced sedimentary structures (MISS), and to distinguish features in modern systems that allow the recognition of such microbial communities in fossil deposits. Systematic biological and sedimentological samplings were carried out, and the identification of microorganisms and the recognition and characterization of typical textures and authigenic minerals were performed through light and electronic microscopy techniques. Microbial mats were dominated by cyanobateria, followed by diatoms; both groups of microorganisms are known to secrete extracellular polymeric substances (EPS) and biostabilize the sedimentary surface. Characteristic textures of epibenthic mats, such as oriented grains and mat-bound small grains, framboidal pyrite and zeolites were recognized. In the intertidal-supratidal zone, MISS termed gas domes, sponge pore fabric, and sieve-like surfaces were identified. Moreover, shrinkage cracks, flip-overs, mat chips, erosional remnants and pockets, folds, as well as multidirected ripple marks were observed. These structures are related to calm conditions/latencies, prolonged subaerial exposure (desiccation), and storm events with high hydrodynamic energy (erosive) acting over the tidal flat (e.g. waves and currents). In this sense, MISS constitute important indicators of specific environmental conditions and thus their recognition in the rock record allows a refined interpretation of the paleoenvironment in coastal marine successions.Fil: Bournod, Constanza Naimé. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Argentino de Oceanografía (i); ArgentinaFil: Cuadrado, Diana G.. Universidad Nacional del Sur. Departamento de Geología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Argentino de Oceanografía (i); ArgentinaFil: Carmona, Noelia Beatriz. Universidad Nacional de Rio Negro. Sede Alto Valle. Instituto de Investigaciones en Paleobiologia y Geologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ponce, Juan Jose. Universidad Nacional de Rio Negro. Sede Alto Valle. Instituto de Investigaciones En Paleobiologia y Geologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pan, Jeronimo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas; Argentin

Planteamiento de mejora y proceso en gestión de seguridad y salud en el trabajo de la empresa Verukas Ingenieros E.I.R.L. - Huacho 2022

Objetivo: Nuestro trabajo de planteamiento y mejora en gestión de SST, es hoy en día muy indispensable en toda empresa. Siendo así la realidad problemática de la empresa Verukas Ingenieros E.I.R.L. con sus trabajadores y el alto índice de accidentes, incidentes y salud. Así mismo, al haber encontrado una pésima gestión de SST por falta de profesionales en el área de SSOMA, existía una ineficiente prevención de trabajo seguro. Las documentaciones que deben estar de forma obligatoria según la Ley 29783, la encontramos en muy malas condiciones, inclinándonos así por la inclusión de SST. Debemos indicar que las supervisiones minuciosas en las diferentes áreas de trabajo no existían, lográndose observar la falta de aceptación de SST por parte de los directivos y trabajadores. Una vez aplicado el sistema de gestión de SST podemos ver en el programa estadístico TStudent que obtenemos de forma satisfactoria el t crítico (valor crítico de t) es “1.68”, t de prueba (estadístico t) es “-14.85”. Siendo así rechazada por los valores obtenidos la hipótesis nul