1,141 research outputs found

    Raman signature of electron-electron correlation in chemically doped few-layer graphene

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    We report an experimental Raman study of few-layer graphene after chemical doping achieved by a plasma process in CHF3_3 gas. A systematic reduction of both the splitting and the area of the 2D band is observed with increasing the doping level. Both effects can be ascribed to the electron-electron correlation, which on the one hand reduces the electron-phonon coupling strength, and on the other hand affects the probability of the double resonant Raman process

    Observation of Raman G-band splitting in top-doped few-layer graphene

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    An experimental study of Raman scattering in N-layer graphene as a function of the top layer doping is reported. At high doping level, achieved by a CHF_3 plasma treatment, we observe a splitting of the GG band in the spectra of bilayer and 4-layer graphene (N even), whereas the splitting is not visible in case of monolayer and trilayer graphene (N odd). The different behaviors are related to distinct electron-phonon interactions, which are affected by symmetry breaking and Fermi level position in different ways in the various N-layer graphenes. In trilayer graphene, a weakening of the electron-phonon coupling as a function of the Fermi energy induces a hardening of all zone-center in-plane optical phonon modes, like in monolayer graphene. On the other hand, in 4-layer graphene two distinct trends are observed in the G band as a function of doping, suggesting the presence of two different groups of electron-phonon interactions, like in bilayer graphene.Comment: 7 pages, 6 figures, to be published in PR

    Histopathologic and biochemical liver test abnormalities in chronic asymptomatic or oligosymptomatic alcoholics: a review

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    PURPOSE: To review the medical literature regarding the histopathologic and biochemical liver test abnormalities in chronic asymptomatic or oligosymptomatic alcoholics. METHODS: Review of articles in the MEDLINE and LILACS databases regarding serum levels and prevalence of alterations in aspartate-aminotransferase, alanine-aminotransferase, alkaline phosphatase, and total bilirubin, in relation to liver histopathology, with or without discrimination of types of histopathologic alteration. RESULTS: Global mean prevalence rates of aspartate-aminotransferase and alanine-aminotransferase alterations were 86.3% and 51.1%; in cases with steatosis they were 79.1% and 38.5%; and in cases of hepatitis, 90.1% and 58%. In all studies, prevalence rates of aspartate-aminotransferase alterations were significantly higher with lower variability than those of alanine-aminotransferase. Mean aspartate-aminotransferase levels were higher than 2N (N is the upper normal limit of the method employed) in all cases with hepatitis histopathology, while those of alanine-aminotransferase were 1.48N, in the same cases. Prevalence of alkaline phosphatase and total bilirubin abnormalities were 74.5% and 74.9% globally; in cases of steatosis, they were 70.9% and 67.9%; and in cases of hepatitis, 75.9% and 77.7%. Mean alkaline phosphatase levels were above the upper normal limit in all cases, but those of total bilirubin were above normal in 4 of 7 hepatitis studies. CONCLUSIONS: Prevalence of aspartate-aminotransferase alteration was consistently related to presence of histopathologic abnormalities; an enzyme level higher than 2N suggests the diagnosis of alcoholic hepatitis.OBJETIVO: Revisar a literatura médica referente às relações entre alterações histopatológicas e testes bioquímicos hepáticos em alcoolistas crônicos assintomáticos ou oligossintomáticos. MÉTODOS: Levantamento, a partir das bases de dados MEDLINE e LILACS e referências em publicações, das prevalências de alterações e níveis séricos da aspartato-aminotransferase, alanino-aminotransferase, fosfatase alcalina e bilirrubina total relacionados com a histopatologia hepática, com e sem discriminação do tipo de alteração histopatológica. RESULTADOS: As taxas médias das prevalências da aspartato-aminotransferase e alanino-aminotransferase foram 86,3% e 51,1% globalmente, sendo 79,1% e 38,5% nos casos de esteatose e 90,1% e 58% nos casos de hepatite, respectivamente. As taxas das prevalências das alterações da aspartato-aminotransferase foram, em todos os estudos, significativamente mais altas e mostraram menores variações que aquelas da alanino-aminotransferase. Os níveis médios da aspartato-aminotransferase foram maiores que 2N (duas vezes superior o limite superior da normalidade) em todos os casos com histopatologia de hepatite, enquanto que os da alanino-aminotransferase, nos mesmos casos, foram 1,48N. As prevalências de alterações da fosfatase alcalina e bilirrubina total foram 74,5% e 74,9% globalmente, 70,9% e 67,9% nos casos de esteatose e 75,9% e 77,7% nos casos de hepatite, respectivamente. Em todos os casos de hepatite, os níveis médios da fosfatase alcalina estavam acima do limite superior da normalidade. Em 4 de 7 estudos sobre pacientes com hepatite a média da bilirrubina total estava acima do normal. CONCLUSÕES: As prevalências de alterações da aspartato-aminotransferase foram consistentemente relacionadas a presença de alterações histopatológicas e o nível elevado da enzima, maior que 2N do método de determinação, sugere o diagnóstico de hepatite alcoólica

    Working with the Revenue code - 1973

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    https://egrove.olemiss.edu/aicpa_guides/2767/thumbnail.jp

    Outlook for Tax Incdentives: The Natural and Extractive Industries, Plenary Session, October 16, 1973, Atlanta Marriott

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    https://egrove.olemiss.edu/aicpa_assoc/1973/thumbnail.jp

    Working with the Revenue Code 1974

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    https://egrove.olemiss.edu/aicpa_guides/2779/thumbnail.jp

    A função de síntese hepática em alcoolistas crônicos assintomáticos ou oligossintomáticos. Correlações com outros testes hepáticos

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    Liver function and its correlation with bilirubin and hepatic enzymes were evaluated in 30 male chronic asymptomatic or oligosymptomatic alcoholics admitted into the psychiatric hospital for detoxification and treatment of alcoholism. Hypoalbuminemia, lowered prothrombin activity, hypotransferrinemia and hypofibrinogenemia were detected in 32 %, 32 %, 28 %, and 24 % of patients, respectively. Transferrin was elevated in 8 %. Greater prevalence of hyperbilirubinemia was found in patients with lowered prothrombin activity, hypofibrinogenemia, or hypotransferrinemia. No correlation was found between serum bilirubin or aminotransferase levels and normal or elevated albumin levels, time or activity of prothrombin, and fibrinogen levels. Serum alkaline phosphatase was elevated in normoalbuminemics and gamma-glutamyltransferase in patients with lowered prothrombin activity. Hypoalbuminemia was associated with hypofibrinogenemia, hypotransferrinemia with elevated aspartate aminotransferase or gamma-glutamyltransferase, and hypertransferrinemia with elevation of alanine aminotransferase. These data indicated the occurrence of hepatic dysfunction due to liver damage caused directly by alcohol or by alcoholism-associated nutritional deficiencies.A função hepática e suas correlações com a bilirrubina e as enzimas hepáticas foram avaliados em 30 alcoolistas crônicos do sexo masculino, assintomáticos ou oligossintomáticos, internados em hospital psiquiátrico para desintoxicação e tratamento do alcoolismo. Hipoalbuminemia, hipoatividade da protrombina, hipofibrinogenemia e hipotransferrinemia ocorreram em 32%, 32%, 24% e 28% dos pacientes, respectivamente. A transferrina estava elevada em 8%. Maior prevalência de hiperbilirrubinemia foi encontrada em pacientes com hipoatividade da protrombina, hipofibrinogemia e hipotransferrinemia. Não observou-se correlações entre os níveis séricos da bilirrubina e das aminotransferases e os níveis normais ou diminuídos da albumina, do tempo e atividade da protrombina e fibrinogênio. Os níveis séricos da fosfatase alcalina estavam mais elevados nos pacientes com normoalbuminemia enquanto que os da gama-glutamiltransferase nos com hipoatividade da protrombina. Hipoalbuminemia estava associada com hipofibrinogenemia, hipotransferrinemia com elevações da aspartato aminotransferase e gamaglutamiltransferase, e hipertransferrinemia com elevação da alanino aminotransferase. Estes dados indicam a ocorrência de disfunção hepática devida a lesão hepática causada diretamente por deficiências nutritivas associadas ao alcoolismo

    The impact of social and relational contexts on innovation transfer in foreign subsidiaries

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    It is widely acknowledged that innovation is one of the pillars of multinational enterprises (MNEs) and that technological knowledge from different host locations is a key factor to the MNEs’ competitive advantages development. Concerning these assumptions, in this paper we aim to understand how the social and the relational contexts affect the conventional and reverse transfer of innovation from MNEs’ subsidiaries hosted in emerging markets. We analyzed the social context through the institutional profile (CIP) level and the relational context through trust and integration levels utilizing a survey sent to 172 foreign subsidiaries located in Brazil, as well as secondary data. Through an ordinary least squares regression (OLS) analysis we found that the relational context affects the conventional and reverse innovation transfer in subsidiaries hosted in emerging markets. We however did not find support for the social context effect

    Huge (but finite) time scales in slow relaxations: beyond simple aging

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    Experiments performed in the last years demonstrated slow relaxations and aging in the conductance of a large variety of materials. Here, we present experimental and theoretical results for conductance relaxation and aging for the case-study example of porous silicon. The relaxations are experimentally observed even at room temperature over timescales of hours, and when a strong electric field is applied for a time twt_w, the ensuing relaxation depends on twt_w. We derive a theoretical curve and show that all experimental data collapse onto it with a single timescale as a fitting parameter. This timescale is found to be of the order of thousands of seconds at room temperature. The generic theory suggested is not fine-tuned to porous silicon, and thus we believe the results should be universal, and the presented method should be applicable for many other systems manifesting memory and other glassy effects.Comment: 4+ pages, 4 figure
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