9 research outputs found

    Late Cretaceous marine transgressions in Ecuador and northern Peru: a refined stratigraphic framework.

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    Study of ammonites and bivalves along selected sections on the Andean margin of northern Peru and Ecuador has made it possible to recognize correlatable marine transgressions and to propose a refined stratigraphic framework for the Upper Cretaceous of the region. Six maximum flooding events are recognized: latest Turonian–early Coniacian (major event), late Coniacian–early Santonian, late Santonian–early Campanian, mid Campanian–early late Campanian (major event), early Maastrichtian (major event), and terminal early Maastrichtian. Most of these events can be correlated with global eustatic sea-level rises, but their relative manifestations indicate that the Andean margin was already being deformed by the late Cretaceous “Peruvian” tectonic events. The onset of fine-grained clastic sedimentation in the Oriente and East-Peruvian basins in the mid Turonian–earliest Coniacian is taken as the first event of the “Peruvian” phase. The Campanian regional transgression in the Peruvian-Ecuadorian forearc zones concealed the “Peruvian” deformational event. The latter caused a palaeogeographic upheaval, indicated by the subsequent development of a NNE-trending forearc basin, which extended from Paita in northwestern Peru to northern Ecuador. In the forearc zones only short-lived transgressions are recorded in the late Campanian and early Maastrichtian as a result of nearly continuous tectonic activity. This culminated with a significant tectonic event in the late Maastrichtian, causing a widespread hiatus

    THE APTIAN STRATIGRAPHY OF SOUTHERN TUARKYR (NW TURKMENISTAN, CENTRAL ASIA)

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    The ammonite successions of Turkmenistan, particularly those of the Greater Balkhan and Tuarkyr areas, are considered references for the Aptian Stage. Six sections across the uppermost Barremian - basal Upper Aptian interval were studied in the Tuarkyr desert in October 1997,and ammonites and bivalves were collected. Data are compared with those from a section sampled by a Russian team in 1959. The stratigraphic distribution of the faunas in the sections is discontinuous, as the fossiliferous levels intercalate with terrigenous sediments. The ammonite faunas, at least in the intervals sampled, show low diversity and are dominated by the genus Deshayesites in the lower Aptian and the genus Epicheloniceras, associated with the less common Caspianites, in the basal upper Aptian. The Turkmenistan sections contain species present also in the Caucasus, England, Germany, France and Switzerland, indicating that the Turkmenian faunas reflect impoverishement rather than geographic isolation. The chronologic equivalence between the Turkmenian Epicheloniceras subnodosocostatum Zone and the Epicheloniceras martinioides Zone in England seems questionable because the Epicheloniceras-bearing beds of the Tuarkyr correspond to the upper part of the E. martinioides Zone, i. e. the Epicheloniceras buxtorfi Subzone. The bivalve fauna consists mainly of pteriids, Exogyrinae oysters and trigoniids. These groups undoubtedly indicate a very shallow, fairly warm and fully marine environment, typical of the Tethyan Lower Cretaceous. The heterodonts are too rare to give further bathymetric indications. None of the taxa indicate deep burrowing and all are assumed to be ?? littoral. The bivalve fauna shows strong affinities with that of the English Lower Greensand.&nbsp

    Minimal information for studies of extracellular vesicles 2018 (MISEV2018):a position statement of the International Society for Extracellular Vesicles and update of the MISEV2014 guidelines

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    The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell-released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles (“MISEV”) guidelines for the field in 2014. We now update these “MISEV2014” guidelines based on evolution of the collective knowledge in the last four years. An important point to consider is that ascribing a specific function to EVs in general, or to subtypes of EVs, requires reporting of specific information beyond mere description of function in a crude, potentially contaminated, and heterogeneous preparation. For example, claims that exosomes are endowed with exquisite and specific activities remain difficult to support experimentally, given our still limited knowledge of their specific molecular machineries of biogenesis and release, as compared with other biophysically similar EVs. The MISEV2018 guidelines include tables and outlines of suggested protocols and steps to follow to document specific EV-associated functional activities. Finally, a checklist is provided with summaries of key points

    Design drawing as a work in itself

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    O design sempre requer desenhos para produção de qualquer objeto. Finalizado o processo de projeto e produção, aparentemente os desenhos esgotariam suas funçÔes. No entanto, alguns desenhos de design sĂŁo elevados a categorias originalmente nĂŁo previstas e afastadas da produção industrial. Uma dessas categorias Ă© o desenho como obra com valor em si, em moldes semelhantes a uma obra de arte. NĂŁo Ă© de hoje que os desenhos de arquitetura e design tĂȘm essas caracterĂ­sticas, ligadas nĂŁo apenas ao processo produtivo, mas tambĂ©m a questĂ”es museolĂłgicas e ao comĂ©rcio de bens culturais, sendo exibidos em museus e comercializados em galerias de arte e casas de leilĂŁo, principalmente na Europa, Estados Unidos e alguns paĂ­ses asiĂĄticos. Este ensaio discute as peculiaridades dos desenhos de design, investigando os diferentes contextos que eventualmente tornam esse tipo de desenho uma obra com valor em si.Design always requires drawings to production, manufacturing and assembly. Essential to best practices in all areas of design, apparently drawings would exhaust its functions at the end of the productive process. However, some drawings being raised to categories not originally foreseen and away from industrial production. One of these categories is drawings as a work in itself, as artwork. It is not from today that design and architecture drawings have these characteristics, linked not only to the productive process, but to museological issues and trade of cultural goods, being exhibited in museums and marketed in art galleries and auction houses, especially in Europe, North America and some Asian countries. This article discusses the peculiarities of design drawings, investigating the different contexts that eventually make this type of drawing a work in itself

    Minimal information for studies of extracellular vesicles 2018 (MISEV2018) : a position statement of the International Society for Extracellular Vesicles and update of the MISEV2014 guidelines

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    The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell-released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles ("MISEV") guidelines for the field in 2014. We now update these "MISEV2014" guidelines based on evolution of the collective knowledge in the last four years. An important point to consider is that ascribing a specific function to EVs in general, or to subtypes of EVs, requires reporting of specific information beyond mere description of function in a crude, potentially contaminated, and heterogeneous preparation. For example, claims that exosomes are endowed with exquisite and specific activities remain difficult to support experimentally, given our still limited knowledge of their specific molecular machineries of biogenesis and release, as compared with other biophysically similar EVs. The MISEV2018 guidelines include tables and outlines of suggested protocols and steps to follow to document specific EV-associated functional activities. Finally, a checklist is provided with summaries of key points

    Minimal information for studies of extracellular vesicles 2018 (MISEV2018): a position statement of the International Society for Extracellular Vesicles and update of the MISEV2014 guidelines

    No full text
    The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell-released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles ("MISEV") guidelines for the field in 2014. We now update these "MISEV2014" guidelines based on evolution of the collective knowledge in the last four years. An important point to consider is that ascribing a specific function to EVs in general, or to subtypes of EVs, requires reporting of specific information beyond mere description of function in a crude, potentially contaminated, and heterogeneous preparation. For example, claims that exosomes are endowed with exquisite and specific activities remain difficult to support experimentally, given our still limited knowledge of their specific molecular machineries of biogenesis and release, as compared with other biophysically similar EVs. The MISEV2018 guidelines include tables and outlines of suggested protocols and steps to follow to document specific EV-associated functional activities. Finally, a checklist is provided with summaries of key points
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