Electron Correlation and Charge Transfer Instability in Bilayered Two Dimensional Electron Gas

We prove that the predicted charge transfer state in symmetric bilayers of two dimensional electron gases is always unstable at zero bias voltage, due to interlayer correlation and/or tunneling. This is most easily seen by resorting to a pseudospin formalism and considering coherent states obtained from the charge transfer state through rotations of the pseudospins. Evidently, the charge transfer state is stabilized by a sufficiently strong gate voltage, as found in recent experiments. We show that a simple model, in which the layers are strictly two dimensional, is able to account quantitatively for such experimental findings, when correlation is properly included.Comment: 5 pages, 3 figures. Subm. to Europhys. Let

Chaoticity and Dissipation of Nuclear Collective Motion in a Classical Model

We analyze the behavior of a gas of classical particles moving in a two-dimensional "nuclear" billiard whose multipole-deformed walls undergo periodic shape oscillations. We demonstrate that a single particle Hamiltonian containing coupling terms between the particles' motion and the collective coordinate induces a chaotic dynamics for any multipolarity, independently on the geometry of the billiard. The absence of coupling terms allows us to recover qualitatively the "wall formula" predictions. We also discuss the dissipative behavior of the wall motion and its relation with the order-to-chaos transition in the dynamics of the microscopic degrees of freedom.Comment: LateX, 11 pages, 7 figures available on request, to appear in the Proceedings of XXXIV Winter Meeting on Nuclear Physics, Bormio 22-27 January, 199

Nonextensive statistical mechanics, superstatistics and beyond: theory and applications in astrophysical and other complex systems

A brief illustration is presented about the scientific motivation and contributions of this Special Issue

Short-term use of dexamethasone/netilmicin fixed combination in controlling ocular inflammation after uncomplicated cataract surgery

Purpose: To evaluate the short-term anti-inflammatory effect of dexamethasone/netilmicin fixed combination in the management of ocular inflammation after cataract surgery. Patients and Methods: Open-label, randomized, active-controlled, clinical study con-ducted in 6 sites in Italy; 238 patients were randomized 2:1 to dexamethasone/netilmicin (dexa/net, n=158) or betamethasone/chloramphenicol (beta/chl, n=80). Treatment started the day of surgery and continued 4 times daily for 7 days. The primary efficacy parameter was the anterior chamber (AC) flare. The percentage of patients displaying none or mild (ie, only barely detectable) AC flare was defined as “efficacy rate”, whereas the percentage of patients showing a decrease of AC flare score from baseline was defined as “percentage of responders”. Additional parameters evaluated were AC cells, conjunctival hyperaemia, corneal and lid oedema, symptoms of ocular discomfort, visual acuity, and intraocular pressure. Dexa/net was considered effective if the efficacy rate was not inferior (by means of 97.5% confidence interval) to that of beta/chl. Results: After 7 days of treatment, no AC flare was observed in 92.8% (dexa/net) and 92.3% (beta/chl) of patients, whereas no AC cells were observed in 91.5% (dexa/net) and 93.6% (beta/chl) of patients, respectively. The “efficacy rate” was 100% in both groups, whereas the “percentage of responders” was 94.1% in the dexa/net and 93.6% in the beta/chl group. The p-value to reject the null hypothesis of inferiority was <0.001. Other efficacy parameters confirmed both treatments as highly effective, despite their difference in steroid content (2 mg/mL for beta/chl vs 1 mg/mL for dexa/net). IOP and visual acuity at the end of the study were comparable. Two cases of allergic conjunctivitis were considered adverse events and were both related to dexa/net. Conclusion: Short-term use of dexa/net fixed combination is safe and effective in the control of post-operative inflammation following uncomplicated cataract surgery

Metsovo Lung: History of Population Environmental Exposure

The historical course of the Metsovo Lung phenomenon began to be investigated in the 1980s when extensive pleural calcifications causing malignant mesothelioma appeared at a high frequency beyond expectation. It was not possible to explain their frequency. This finding reasonably raised the question of whether it was indeed tuberculous pleurisy or something else. The biopsies carried out confirmed that these were tremolite asbestos fibres. These fibres were derived from a shielding material containing asbestos. This is a global phenomenon according to which the entire population of Metsovo was exposed to asbestos, without knowing it, from a traditional shielding material. The abandonment of the material and its non-use brought about a gradual reduction of the phenomenon, which also marks the reduction of mesothelioma