6 research outputs found

    Reflectivity Anisotropy Spectra of Cu- and Ag- (110) surfaces from {\it ab initio} theory

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    We are able to disentagle the effects of the intraband and interband parts of the bulk dielectric function on the bare dielectric anisotropy of the surface. We show how the position, sign and amplitude of the structures observed in such spectra depend on the above quantities. The lineshape of all the calculated structures agree very well with the ones observed experimentally for samples treated by suitable surface cleaning. In particular, we reproduce the observed single peak structure of Ag at high energy, found to represent a state of the clean surface different from the one giving the originally observed double peak structure. This results is not reproduced by the 'local field' model.Comment: 4 pages, 3 figures. submitted to Phys. Rev. Let

    Experimental and Theoretical Investigation of the Pyrrole/Al(100)Interface

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    The electronic properties of the pyrrole/Al(100) interface have beeninvestigated from both a theoretical and experimental point of view.Electron energy loss spectroscopy (EELS) in specular reflectiongeometry does not reveal modification of the electronic structure ofthe molecule when adsorbed on the Al surface. EELS results and the lowdesorption temperature of pyrrole indicate a weak molecule/metalinteraction. Ab initio calculations in the framework of thesingle-particle density functional theory within the local densityapproximation was used to investigate the adsorption energy andgeometry. The low adsorption energy, -0.51 eV per molecule, and thehigh N-Al distance, 1.98 angstrom, confirm the weak interaction ofpyrrole adsorbed on the Al Surface

    Assessment of the awareness and management of sleep apnea syndrome in acromegaly. The COM.E.TA (Comorbidities Evaluation and Treatment in Acromegaly) Italian Study Group.

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    In 2007 the Italian COM.E.T.A. (COMorbidities Evaluation and Treatment in Acromegaly) study group started to assess the application in a clinical setting of the Versailles criteria for management of acromegaly complications by a first questionnaire focusing on cardiovascular co-morbidities. A further questionnaire on sleep apnea syndrome (SAS) was delivered by the COM.E.T.A. study group to 107 endocrine centers in Italy. The results of our survey suggest that SAS is a well-known comorbidity even if its estimated prevalence is lower than in the literature. Polysomnography is the preferred tool for diagnosis. Control of SAS is considered relevant both for quality of life and co-morbidities. Continuous positive airway pressure is the cornerstone of therapy, but patients' acceptance may be critical. Control of GH/IGF-I secretion is important to improve SAS. Management of SAS requires cooperation between specialists. ©2011, Editrice Kurtis
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