Distributed power control over interference channels using ACK/NACK feedback

In this work, we consider a network composed of several single-antenna transmitter-receiver pairs in which each pair aims at selfishly minimizing the power required to achieve a given signal-to-interference-plus-noise ratio. This is obtained modeling the transmitter-receiver pairs as rational agents that engage in a non-cooperative game. Capitalizing on the well-known results on the existence and structure of the generalized Nash equilibrium (GNE) point of the underlying game, a low complexity, iterative and distributed algorithm is derived to let each terminal reach the GNE using only a limited feedback in the form of link-layer acknowledgement (ACK) or negative acknowledgement (NACK). Numerical results are used to prove that the proposed solution is able to achieve convergence in a scalable and adaptive manner under different operating conditions.Comment: 5 pages, 6 figures, IEEE Global Communications Conference (GLOBECOM), Austin, Texas, Dec. 201

Stationary growth and unique invariant harmonic measure of cylindrical DLA

We prove that the harmonic measure is stationary, unique and invariant on the interface of DLA growing on a cylinder surface. We provide a detailed theoretical analysis puzzling together multiscaling, multifractality and conformal invariance, supported by extensive numerical simulations of clusters built using conformal mappings and on lattice. The growth properties of the active and frozen zones are clearly elucidated. We show that the unique scaling exponent characterizing the stationary growth is the DLA fractal dimension

Electron corrected Lorentz forces in solids and molecules in magnetic field

We describe the effective Lorentz forces on the ions of a generic insulating system in an magnetic field, in the context of Born-Oppenheimer ab-initio molecular dynamics. The force on each ion includes an important contribution of electronic origin, which depends explicitly on the velocity of all other ions. It is formulated in terms of a Berry curvature, in a form directly suitable for future first principles classical dynamics simulations based {\it e.g.,} on density functional methods. As a preliminary analytical demonstration we present the dynamics of an H$_2$ molecule in a field of intermediate strength, approximately describing the electrons through Slater's variational wavefunction.Comment: 5 pages, 2 figures; to appear in Phys. Rev.

Cambiamenti di copertura forestale e dell’uso del suolo nell’inventario dell’uso delle terre in Italia

Changes of forest coverage and land uses as assessed by the inventory of land uses in Italy. The paper presents the IUTI program, a land use inventory of Italy, based on point sampling. It has been carried out to support the National Carbon Sink Accounting Register and it was realized within the framework of the Italian National Remote Sensing Plan managed by the Italian Ministry of Environment. IUTI has monitored the land use and land use change and forestry in the last two decades over the country at the years 1990, 2000, 2008, adopting a tessellated stratified sampling scheme with about 1.2 million sample points on aerial orthophotos. Following definitions, methods and inventory procedures, the main results are discussed. They show the heavy changes affecting surface and distribution of the various classes for arable lands, forests and urban areas.L'articolo è disponibile sul sito dell'editore www.sisef.i

The versatile chemistry of niobium pentachloride with aliphatic amines: Aminolysis, metal reduction and C–H activation

The reactions of NbCl5 with limited amounts (1-2 molar equivalents) of a series of primary, secondary and tertiary amines were investigated in dichloromethane as solvent. The 1:1 reaction of NbCl5 with NHEt2 cleanly afforded an equimolar mixture of [NbCl4(NEt2)]2, 1, and [NH2Et2][NbCl6], 2a; the former product constitutes the first example of structurally characterized Nb(V) chlorido-amido complex. The ammonium salts [NH3nPr][NbCl6], 2b, and [NH2iPr2][NbCl6], 2c, were isolated in 20-30% yields from the 1:1 reactions of NbCl5 with NH2nPr and NHiPr2, respectively. Cα-H bond activation and Nb(V) to Nb(IV) reduction took place in the reactions of NbCl5 with NR3 (R = Bz, Et; Bz = CH2Ph). The iminium salt [(PhCH2)2N=CHPh][NbCl6], 3, and the ammonium ion [NH(CH2Ph)3]+ were identified as the prevalent species generated from the 1:1 NbCl5/NBz3 interaction. [NHEt3][NbCl6], 4, and [NHEt3]2[NbCl6], 5, were isolated in moderate yields from, respectively, the 1:1 and 1:2 molar reactions of NbCl5 with NEt3. The solid state structures of 1, 2a, 3, 4 and 5 were ascertained by single crystal X-ray studies

Estimating forest area at the year 1990 by two-phase sampling on historical remotely sensed imagery in Italy

Forest area in the year 1990 is a fi gure of great interest under the Kyoto Protocol. This note is devoted to a scientifi c exercise for the probabilistic ex post assessment of such a fi gure in Italy. Estimation was performed by twophase point sampling, which made use of historical remotely sensed imagery. In the fi rst phase, a sample of 12 089 points was selected according to an unaligned systematic sampling and the selected points were classifi ed in land-use categories by Landsat 5 TM imagery. In the second phase, a sample of 3000 points was selected by stratifi ed sampling in which the strata were determined by the satellite classifi cation and the selected points were classifi ed by aerial photos, assumed as ground truth. A two-phase estimate of land-use coverage partitioning the Italian territory was obtained together with a conservative estimate of the sampling variance-covariance. The procedure has proved to be of relatively easy implementation and objective repeatabilityL'articolo è disponibile sul sito dell'editore http://www.springerlink.com

Spread of SARS-CoV-2 (COVID-19) in a High-Volume Hospital: Vascular Surgery Impact

Increasing population rates of coronavirus disease 2019 (COVID-19) are occurring in several countries and continents. The impact regarding vascular activity, consequences and complication is scarce and makes the future perspective unclear. The aim of this report is to describe the changes in a high-volume University Hospital, relevant for future decisions. The mortality and morbidity should be higher not only in COVID+ patients but also in vascular patients

Primary Corneal Squamous Cell Carcinoma in a Dog: Clinical and Histopathological Evaluation

An 8-year-old male pug with a 12-month history of a progressive nonpainful mass on the left cornea was evaluated. Ocular examination showed a severe bilateral keratoconjunctivitis sicca, pigmentary keratitis, and an exophytic irregular pink mass occupying approximately 75% of the total corneal surface of the left eye. A squamous cell carcinoma (SCC) was suspected on cytology, and clinical investigations showed no evidence of metastases. A transpalpebral enucleation was therefore performed, and the diagnosis of SCC was confirmed on histopathology. Immunohistochemical investigations showed that the neoplastic cells were pan-cytokeratin positive and vimentin negative. Additionally, nuclei immunoreactive to Ki-67 antigen were detected. Tumor cells were also negative to p53. Immunoreactivity to COX-2 was found in less than 10% of the neoplastic cells. No adjuvant therapies were instituted, and no evidence of local recurrence or distance metastasis was identified during the 24-month follow-up period