Effective potential in Lorentz-breaking field theory models

We calculate explicitly the one-loop effective potential in different Lorentz-breaking field theory models. First, we consider a Yukawa-like theory and, then, some examples of Lorentz-violating extensions of scalar QED. We observed, for the extended QED models, that the resulting effective potential converges to the known result in the limit in which Lorentz-symmetry is restored. Besides, the one-loop corrections to the effective potential in all the cases we studied depend on the background tensors responsible for the Lorentz symmetry violation. This have consequences in physical quantities like, for example, in the induced mass due to Coleman-Weinberg mechanism.Comment: Version accepted for publication in EPJ

Fatores de risco envolvidos na dermatite necrótica dos frangos de corte.

Projeto/Plano de Ação: 16.00.30.004

Leg ulcer as a manifestation of eosinophilic vasculitis in a patient with hepatitis C virus infection, medicated with pegylated interferon/ribavirin.

Cryoglobulinaemic vasculitis is a complication of hepatitis C virus (HCV) infection, responding to treatment with pegylated interferon (peg-IFN)/ribavirin (RIB), but vasculitis may first appear after treatment with peg-IFN/RIB. A 35-year-old man with HCV infection presented to our department with a 2-month history of a 3.3×3 cm ulcer localised on the right shin, with a regular border, on a violaceous base. Histopathological examination revealed a leucocytoclastic vasculitis, rich in eosinophils. The patient had been treated with peg-IFN/RIB 10 months prior and treatment was discontinued after 2 months because of the appearance of arthralgias and neuropathy. Laboratory investigations revealed positive cryoglobulins, elevation of rheumatoid factor and reduction of C4 after treatment with peg-IFN/RIB. Dressings with a hydrocellular foam were placed and after 2 months the ulcer resolved. We presented this case because of the rarity of development of a cryoglobulinaemic vasculitis in a patient with HCV infection, previously treated with peg-IFN/RIB