1,019 research outputs found

    C60_{60} in Reflection Nebulae

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    The fullerene C60_{60} has four infrared-active vibrational transitions at 7.0, 8.5, 17.4 and 18.9 μ\mum. We have previously observed emission features at 17.4 and 18.9 μ\mum in the reflection nebula NGC 7023 and demonstrated spatial correlations suggestive of a common origin. We now confirm our earlier identification of these features with C60_{60} by detecting a third emission feature at 7.04 ±\pm 0.05 μ\mum in NGC 7023. We also report the detection of these three C60_{60} features in the reflection nebula NGC 2023. Our spectroscopic mapping of NGC 7023 shows that the 18.9 μ\mum C60_{60} feature peaks on the central star and that the 16.4 μ\mum emission feature due to polycyclic aromatic hydrocarbons peaks between the star and a nearby photodissociation front. The observed features in NGC 7023 are consistent with emission from UV-excited gas-phase C60_{60}. We find that 0.1-0.6% of interstellar carbon is in C60_{60}; this abundance is consistent with those from previous upper limits and possible fullerene detections in the interstellar medium. This is the first firm detection of neutral C60_{60} in the interstellar medium.Comment: ApJ Letters, in pres

    Formation of PAHs and Carbonaceous Solids in Gas-Phase Condensation Experiments

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    Carbonaceous grains represent a major component of cosmic dust. In order to understand their formation pathways, they have been prepared in the laboratory by gas-phase condensation reactions such as laser pyrolysis and laser ablation. Our studies demonstrate that the temperature in the condensation zone determines the formation pathway of carbonaceous particles. At temperatures lower than 1700 K, the condensation by-products are mainly polycyclic aromatic hydrocarbons (PAHs), that are also the precursors or building blocks for the condensing soot grains. The low-temperature condensates contain PAH mixtures that are mainly composed of volatile 3-5 ring systems. At condensation temperatures higher than 3500 K, fullerene-like carbon grains and fullerene compounds are formed. Fullerene fragments or complete fullerenes equip the nucleating particles. Fullerenes can be identified as soluble components. Consequently, condensation products in cool and hot astrophysical environments such as cool and hot AGB stars or Wolf Rayet stars should be different and should have distinct spectral properties.Comment: 7 pages, 5 figure

    Ground deformation analysis at Campi Flegrei (Southern Italy) by CGPS and tide-gauge network

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    Campi Flegrei caldera is located 15 km west of the city of Naples, within the central-southern sector of a large graben called Campanian Plain. It is an active volcanic area marked by a quasi-circular caldera depression, formed by a huge ignimbritic eruption occurred about 37000 years ago. This caldera was generated by several collapses produced by strong explosive eruptions (the last eruption, occurred in 1538, built an about 130 m spatter cone called Mt. Nuovo). Campi Flegrei area periodically experiences significant deformation episodes, with uplift phenomena up to more than 3.5 m in 15 years (from 1970 to 1984), which caused during 1983-84 the temporary evacuation of about 40000 people from the ancient part of Pozzuoli town. The deformation field obtainable by CGPS and tidegauge stations plays an important role for the modelling and interpretation of volcanic phenomena, as well as for forecasting purposes. The structural complexity of the Campi Flegrei area, together with the evidence of a strong interaction between magmatic chamber and shallow geothermal system, calls for a detailed characterization of the substructure and of magma-water interaction processes. The incoming experiment of deep drilling, down to about 4 km, will give detailed structural and physical constraints able to resolve the intrinsic ambiguities of geophysical data and in particular geodetic ones. In this poster we describe the recent ground deformations at Campi Flegrei area by means of GPS technique and tide gauge stations, discussing the possible interpretations also in light of further constraints likely coming from the next CFDDP (Campi Flegrei Deep Drilling) deep drilling experiment

    AN ULTRASENSITIVE VIBRATING PROBE FOR MEASURING STEADY EXTRACELLULAR CURRENTS

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    We describe a vibrating probe system for measuring relatively steady electrical current densities near individual living cells. It has a signal-to-noise ratio at least 100 times greater than previously available techniques. Thus it can be used to detect current densities as small as 10 nA/cm2 in serum when a 30-µm diameter probe is vibrated at 200 Hz between two points 30 µm apart, and the amplifier's time constant is set at 10 s. Moreover, it should be generally insensitive to interference by concentration gradients. It has been first used to reveal and study 100-s long current pulses which developing fucoid embryos drive through themselves

    Argentina 4.0: evolución, oportunidades y desafíos para un Gobierno Digital

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    Argentina’s digital transformation in public administration represents a significant shift in government management, aiming to optimize processes, reduce bureaucracy, and enhance the interaction between the State and its citizens. This article examines the evolution of Digital Government in Argentina from two perspectives: regulatory (of law) and practical (in fact). It highlights advancements such as the implementation of systems like Electronic Document Management (GDE) and Remote Procedures (TAD), alongside a legal framework promoting paperless processes, automation, and interoperability. Despite these achievements, the text addresses current challenges, including the need to strengthen interoperability, bolster cybersecurity, and integrate emerging technologies such as artificial intelligence to achieve a truly digital, efficient, and people-centered government.La transformación digital del gobierno argentino representa un cambio significativo en la gestión pública, orientado a optimizar procesos, reducir burocracia y mejorar la relación entre el Estado y los ciudadanos. Este artículo analiza la evolución del Gobierno Digital en Argentina desde dos perspectivas: normativa (de derecho) y práctica (de hecho). Se destacan avances como la implementación de sistemas como Gestión Documental Electrónica (GDE) y Trámites a Distancia (TAD), así como el desarrollo de un marco normativo que promueve la despapelización, la automatización y la interoperabilidad. A pesar de los logros, el texto aborda los desafíos actuales, como la necesidad de consolidar la interoperabilidad, fortalecer la ciberseguridad e incorporar tecnologías emergentes como la inteligencia artificial para alcanzar un gobierno verdaderamente digital, inteligente, eficiente y centrado en las personas

    Chromosome microarray analysis as first-line test in pregnancies with a priori low risk for detection of submicroscopic chromosomal abnormalities

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    n this study, we aimed to explore the utility of chromosomal microarray analysis (CMA) in groups of pregnancies with a priori low risk for detection of submicroscopic chromosome abnormalities, usually not considered an indication for testing, in order to assess whether CMA improves the detection rate of prenatal chromosomal aberrations. A total of 3000 prenatal samples were processed in parallel using both whole-genome CMA and conventional karyotyping. The indications for prenatal testing included: advanced maternal age, maternal serum screening test abnormality, abnormal ultrasound findings, known abnormal fetal karyotype, parental anxiety, family history of a genetic condition and cell culture failure. The use of CMA resulted in an increased detection rate regardless of the indication for analysis. This was evident in high risk groups (abnormal ultrasound findings and abnormal fetal karyotype), in which the percentage of detection was 5.8% (7/120), and also in low risk groups, such as advanced maternal age (6/1118, 0.5%), and parental anxiety (11/1674, 0.7%). A total of 24 (0.8%) fetal conditions would have remained undiagnosed if only a standard karyotype had been performed. Importantly, 17 (0.6%) of such findings would have otherwise been overlooked if CMA was offered only to high risk pregnancies.The results of this study suggest that more widespread CMA testing of fetuses would result in a higher detection of clinically relevant chromosome abnormalities, even in low risk pregnancies. Our findings provide substantial evidence for the introduction of CMA as a first-line diagnostic test for all pregnant women undergoing invasive prenatal testing, regardless of risk factors

    Third brazilian consensus for autoantIbodies screening in HEp-2 Cells : historical perspectve, quality control and clinical associatons

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    O III Consenso Brasileiro para Pesquisa de Autoanticorpos em Células HEp-2 (FAN) objetivou discutir estratégias para controlar a qualidade do ensaio, promover a atualização das associações clínicas dos diversos padrões e avaliar as difculdades de implantação do II Consenso ocorrido no ano de 2002. Métodos: Nos dias 13 e 14 de abril de 2007 participaram do encontro em Goiânia pesquisadores e especialistas de diversos centros universitários e laboratórios clínicos de diferentes regiões do Brasil, com o propósito de discutir e aprovar as recomendações que visam a melhores padronização, interpretação e utilização do ensaio pelos clínicos. Foram convidados como ouvintes representantes comerciais de diferentes empresas produtoras de insumos para realização do teste de FAN. Resultados e conclusão: Dada a heterogeneidade de microscópios e reagentes disponíveis no mercado, o III Consenso enfatizou a necessidade do controle de qualidade em ensaios de imunofuorescência indireta. Foram também feitas algumas adequações na terminologia utilizada para classifcar os diferentes padrões. Finalmente, foi realizada uma atualização das associações clínicas com fnalidade de facilitar cada vez mais o melhor uso do ensaio pelos clínicos. _________________________________________________________________________________ ABSTRACTThe Third Brazilian Consensus for Autoantibodies Screening in HEp-2 Cells (ANA) had as purpose the evaluation of diffculties in the accomplishment of the 2nd Consensus recommendations that took place in the year of 2002, the discussion of strategies for quality control of the assay and the discussion of an update of the clinical associations of the several immunofuorescent patterns. Methods: Several ANA experts from university centers and private laboratories in different areas in Brazil joined the workshop in Goiânia on 2007 April 13 and 14 with the purpose of discussing and approving the recommendations for standardization, interpretation and use of the test by physicians. Commercial representatives of different ANA slide brands were also invited as listeners to the workshop. Results and conclusion: The 3rd ANA Consensus emphasized the need for quality control in indirect immunofuorescent assays since there is a considerable heterogeneity of available microscopes and reagents. It also promoted adaptations in the previously approved terminology used to classify the different patterns and fnally updated the clinical associations of the several patterns with the purpose of providing guidance for interpretation of the assay by clinical pathologists and assistant physicians

    Third Brazilian consensus for autoantibodies screening in HEp-2 cells (ANA) : recommendations for standardization of autoantibodies screening trial in HEp-2 cells, quality control and clinical associations

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    Objetivo: O 3º Consenso Brasileiro para pesquisa de autoanticorpos em Células HEp-2 (FAN) teve como propósito avaliar as dificuldades de implantação do 2º Consenso ocorrido no ano de 2002, discutir estratégias para controlar a qualidade do ensaio e promover a atualização das associações clínicas dos diversos padrões. Métodos: Participaram do encontro em Goiânia nos dias 13 e 14 de abril de 2008 pesquisadores e especialistas de diversos centros universitários e laboratórios clínicos de diferentes regiões do Brasil, com o propósito de discutir e aprovar as recomendações que visam à melhor padronização, interpretação e utilização do ensaio pelos clínicos. Representantes comerciais de diferentes empresas produtoras de insumos para realização do teste de FAN foram convidados como ouvintes. Resultados e Conclusões: O 3º Consenso enfatizou a necessidade do controle de qualidade em imunofluorescência dada a heterogeneidade de microscópios e reagentes disponíveis no mercado, promoveu adequações na terminologia utilizada para classificar os diferentes padrões e, finalmente, atualizou as associações clínicas com finalidade de facilitar cada vez mais o melhor uso do ensaio pelos clínicos. ________________________________________________________________________________ ABSTRACTObjective: The Third Brazilian Consensus for autoantibodies Screening in HEp-2 cells had as purpose the evaluation of difficulties in the accomplishment of the 2nd Consensus recommendations that took place in the year of 2002, the discussion of strategies for quality control of the assay and the promotion of an update of the clinical associations of the several immunofluorescent patterns. Methods: Several ANA experts from university centers and private laboratories in different areas in Brazil joined the workshop in Goiânia on 2008 April 13 and 14 with the purpose of discussing and approving the recommendations for standardization, interpretation and use of the test by physicians. Commercial representatives of different ANA slide brands were also invited as listeners to the workshop. Results and Conclusions: The 3rd Consensus emphasized the need for quality control in indirect immunofluorescent since there is a considerable heterogeneity of available microscopes and reagents. It also promoted adaptations in the previously approved terminology used to classify the different patterns and finally updated the clinical associations of the several patterns with the purpose of providing guidance for interpretation of the assay by clinical pathologists and assistant physicians
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