270 research outputs found

    Surface-state electron dynamics in noble metals

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    Theoretical investigations of surface-state electron dynamics in noble metals are reported. The dynamically screened interaction is computed, within many-body theory, by going beyond a free-electron description of the metal surface. Calculations of the inelastic linewidth of Shockley surface-state electrons and holes in these materials are also presented. While the linewidth of excited holes at the surface-state band edge (k=0{\bf k}_\parallel=0) is dominated by a two-dimensional decay channel, within the surface-state band itself, our calculations indicate that major contributions to the electron-electron interaction of surface-state electrons above the Fermi level come from the underlying bulk electrons.Comment: 17 pages, 7 figures, to appear in Prog. Surf. Sc

    Arteriovenous malformations of the lung: diagnosis by thin-section HRCT and Cine-MRI

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    We report a case in which a solitary large and multiple group of small pulmonary arteriovenous malformations were demonstrated by computed tomography and magnetic resonance images that could aid diagnosis and therapeutic planning without the need for catheter angiography

    Insider trading restrictions and earnings management

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    We study whether firms that voluntarily restrict insider trading have lower incentives for earnings management. Using a large sample of US firms, we measure these restrictions based on the extent to which insider transactions happen shortly after quarterly earnings announcements. We find that the adoption of insider trading restrictions is associated with a reduction of 9.92 percent in absolute discretionary accruals. Our findings are robust to controlling for changes in corporate governance, and we do not find evidence of a substitution effect between accruals and real earnings management, target beating or timeliness of loss recognition. Taken together, our results indicate that the voluntary adoption of blackout periods that limit insider trading improves the quality of financial reporting

    MedivozCaptura. Una aplicación en red segura de ayuda al profesional de ORL

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    MedivozCaptura es una herramienta informática desarrollada para asistir al análisis y detección de patologías vocales. Se basa en el almacenamiento en una base de datos relacional de señales de voz, electroglotogramas (EGG) y vídeoendoscopias, además de otros datos sobre los pacientes que los especialistas puedan considerar relevantes. El presente documento describe el funcionamiento de la aplicación de forma distribuida en red, con la base de datos centralizada, así como la problemática de seguridad y rendimiento que supone la distribución a través de la red o Internet y cómo se solventa en MedivozCaptur

    Self-energy of image states on copper surfaces

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    We report extensive calculations of the imaginary part of the electron self-energy in the vicinity of the (100) and (111) surfaces of Cu. The quasiparticle self-energy is computed by going beyond a free-electron description of the metal surface, either within the GW approximation of many-body theory or with inclusion, within the GWΓ\Gamma approximation, of short-range exchange-correlation effects. Calculations of the decay rate of the first three image states on Cu(100) and the first image state on Cu(111) are also reported, and the impact of both band structure and many-body effects on the electron relaxation process is discussed.Comment: 8 pages, 5 figures, to appear in Phys. Rev.

    Pandemia e Impacto en los procesos de Investigación, Desarrollo e Innovación I+D+i

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    Sin duda alguna uno de los eventos más trascendentales que han sucedidoen este siglo es la pandemia provocada por el virus SARS-COV-2, impactando fuertemente en todos los aspectos sociales y económicosa nivel mundial, incluyendo el avance de la ciencia y la tecnología

    Methemoglobinemia presenting in a circumcised baby following application of prilocaine: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Local anesthesia with prilocaine has become a routine part of ambulatory circumcision procedures. Methemoglobinemia is a rare but potentially lethal complication of local anesthetics.</p> <p>Case presentation</p> <p>We report the case of a 40-day-old Turkish boy who presented with cyanosis after receiving local anesthesia with prilocaine. His methemoglobin level revealed severe methemoglobinemia (methemoglobin = 44%). His cyanosis resolved after intravenous administration of methylene blue.</p> <p>Conclusion</p> <p>Although the association between prilocaine use and methemoglobinemia has generally restricted the use of prilocaine in babies, it is still widely used in ambulatory procedures, especially during circumcision in the neonatal period. Prilocaine should not be used in babies who are less than 3 months old because of the risk of methemoglobinemia; other local anesthetics may be used for this age group. Furthermore, general anesthesia by mask ventilation may be favored for babies less than 3 months of age instead of local anesthetics.</p
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