Simbol-X capability of detecting the non-thermal emission of stellar flares

We investigate the capability of detecting, with Simbol-X, non-thermal emission during stellar flares, and distinguishing it from hot thermal emission. We find that flare non-thermal emission is detectable when at least ~20 cts are detected with the CZT detector in the 20-80 keV band. Therefore Simbol-X will detect the non-thermal emission from some of the X-ray brightest nearby stars, whether the thermal vs. non-thermal relation, derived for solar flares, holds.Comment: 2 pages, 2 postscript figures, proceedings of the workshop "Simbol-X: the hard X-ray universe in focus", to be published in "Memorie of the Italian Astronomical Society

FUV variability of HD 189733. Is the star accreting material from its hot Jupiter?

Hot Jupiters are subject to strong irradiation from the host stars and, as a consequence, they do evaporate. They can also interact with the parent stars by means of tides and magnetic fields. Both phenomena have strong implications for the evolution of these systems. Here we present time resolved spectroscopy of HD~189733 observed with the Cosmic Origin Spectrograph (COS) on board to HST. The star has been observed during five consecutive HST orbits, starting at a secondary transit of the planet ($\phi$ ~0.50-0.63). Two main episodes of variability of ion lines of Si, C, N and O are detected, with an increase of line fluxes. Si IV lines show the highest degree of variability. The FUV variability is a signature of enhanced activity in phase with the planet motion, occurring after the planet egress, as already observed three times in X-rays. With the support of MHD simulations, we propose the following interpretation: a stream of gas evaporating from the planet is actively and almost steadily accreting onto the stellar surface, impacting at $70-90\deg$ ahead of the sub-planetary point.Comment: 35 pages, 19 Figures. Accepted for publication to Ap

Strong-coupling analysis of scanning tunneling spectra in Bi2_2Sr2_2Ca2_2Cu3_3O10+δ_{10+\delta}

We study a series of spectra measured in the superconducting state of optimally-doped Bi-2223 by scanning tunneling spectroscopy. Each spectrum, as well as the average of spectra presenting the same gap, is fitted using a strong-coupling model taking into account the band structure, the BCS gap, and the interaction of electrons with the spin resonance. After describing our measurements and the main characteristics of the strong-coupling model, we report the whole set of parameters determined from the fits, and we discuss trends as a function of the gap magnitude. We also simulate angle-resolved photoemission spectra, and compare with recent experimental results.Comment: Published versio

Kawasaki disease triggered by EBV virus in a child with Familial Mediterranean Fever

Familial Mediterranean Fever is a monogenic autoinflammatory disease, secondary to mutation of MEFV gene, and typically expressed with recurrent attacks of fever, serositis, rash, aphthous changes in lips and/or oral mucosa. Kawasaki Disease, an acute systemic vasculitis with persistent fever (5 or more days), rash, stomatitis, conjunctivitis, lymphadenopathy, changes in extremities, is currently considered a multifactorial autoinflammatory disease. An infection, as Epstein Barr virus, can be the trigger of Kawasaki Disease

Familial Mediterranean Fever: An unusual cause of liver disease

Background Familial Mediterranean Fever is an autoinflammatory disease typically expressed with recurrent attacks of fever, serositis, aphthous stomatitis, rash. Only a few reports describe the association with hepatic involvement. Case presentation We describe the clinical case of a child affected, since the age of 1 year, by recurrent fever, aphthous stomatitis, rash, arthralgia, associated with abdominal pain, vomiting, lymphadenopathy. The diagnosis of Familial Mediterranean Fever was confirmed by the genetic study of MEFV gene; the homozygous mutation M694 V in exon was documented. A partial control of attacks was obtained with colchicine. The child continued to manifest only recurrent episodes of abdominal pain without fever, however serum amyloid A persisted high, in association with enhanced levels of CRP, AST and ALT (1.5 x n.v.). The dosage of colchicine was increased step by step and the patient achieved a better control of symptoms and biochemical parameters. However, the patient frequently needed an increase in the dose of colchicine, suggesting the possible usefulness of anti-interleukin-1 beta treatment. Conclusions The unusual presentation of Familial Mediterranean Fever with liver disease suggests the role of inflammasome in hepatic inflammation. Colchicine controls systemic inflammation in most of the patients; however, subclinical inflammation can persist in some of them and can manifest with increased levels of CRP, ESR, serum amyloid A also in attack-free intervals