579 research outputs found
Delocalization and wave-packet dynamics in one-dimensional diluted Anderson models
We study the nature of one-electron eigen-states in a one-dimensional diluted
Anderson model where every Anderson impurity is diluted by a periodic function
. Using renormalization group and transfer matrix techniques, we provide
accurate estimates of the extended states which appear in this model, whose
number depends on the symmetry of the diluting function . The density of
states (DOS) for this model is also numerically obtained and its main features
are related to the symmetries of the diluting function . Further, we show
that the emergence of extended states promotes a sub-diffusive spread of an
initially localized wave-packet.Comment: 6 pages, 6 figures, to appear in EPJ
Majority-Vote Model on a Random Lattice
The stationary critical properties of the isotropic majority vote model on
random lattices with quenched connectivity disorder are calculated by using
Monte Carlo simulations and finite size analysis. The critical exponents
and are found to be different from those of the Ising and
majority vote on the square lattice model and the critical noise parameter is
found to be .Comment: 4 pages, 6 figure
Il Nibbio reale Milvus milvus svernante in Italia, sintesi di cinque anni di monitoraggio
Beginning in December 2011, CISO has promoted a monitoring project for Red kite\u2019s wintering population in Italy. This paper shows the results of the first five survey seasons, ie from December 2011 to January 2016. The censuses, always done at sunset, covered the eleven Central-Southern regions for which winter roosts were already known. The number of actual kites censuses each winter varied between about 1500 and over 1700 individuals, with strong oscillations for single roosts. The population is mainly concentrated in Basilicata with more than 64% of the entire winter population. Interesting data were also been found in Lazio, Abruzzo and Molise, which altogether host about 25% of the national population. Encouraging data come from Tuscany where, following a reintroduction project, a wintering roost of about 80 units was found. Bad results are from censuses conducted in Campania, Calabria, Sicily and Sardinia, where the population seems to be greatly reduced
Black hole thermodynamical entropy
As early as 1902, Gibbs pointed out that systems whose partition function
diverges, e.g. gravitation, lie outside the validity of the Boltzmann-Gibbs
(BG) theory. Consistently, since the pioneering Bekenstein-Hawking results,
physically meaningful evidence (e.g., the holographic principle) has
accumulated that the BG entropy of a black hole is
proportional to its area ( being a characteristic linear length), and
not to its volume . Similarly it exists the \emph{area law}, so named
because, for a wide class of strongly quantum-entangled -dimensional
systems, is proportional to if , and to if
, instead of being proportional to (). These results
violate the extensivity of the thermodynamical entropy of a -dimensional
system. This thermodynamical inconsistency disappears if we realize that the
thermodynamical entropy of such nonstandard systems is \emph{not} to be
identified with the BG {\it additive} entropy but with appropriately
generalized {\it nonadditive} entropies. Indeed, the celebrated usefulness of
the BG entropy is founded on hypothesis such as relatively weak probabilistic
correlations (and their connections to ergodicity, which by no means can be
assumed as a general rule of nature). Here we introduce a generalized entropy
which, for the Schwarzschild black hole and the area law, can solve the
thermodynamic puzzle.Comment: 7 pages, 2 figures. Accepted for publication in EPJ
Il Nibbio reale Milvus milvus svernante in Italia, sintesi di cinque anni di monitoraggio
Beginning in December 2011, CISO has promoted a monitoring project for Red kite\u2019s wintering population in Italy. This paper shows the results of the first five survey seasons, ie from December 2011 to January 2016. The censuses, always done at sunset, covered the eleven Central-Southern regions for which winter roosts were already known. The number of actual kites censuses each winter varied between about 1500 and over 1700 individuals, with strong oscillations for single roosts. The population is mainly concentrated in Basilicata with more than 64% of the entire winter population. Interesting data were also been found in Lazio, Abruzzo and Molise, which altogether host about 25% of the national population. Encouraging data come from Tuscany where, following a reintroduction project, a wintering roost of about 80 units was found. Bad results are from censuses conducted in Campania, Calabria, Sicily and Sardinia, where the population seems to be greatly reduced
Environmental impact reduction of precast multi-storey buildings by crescent-moon seismic dampers hidden in beam-column joints
The growing demand of sustainable precast structures for multi-storey con-structions is often driven by the optimisation of cross-sections and reinforcement volumes of the structural elements. The present paper describes a real building recently designed and assembled with the installation of crescent-moon hysteretic dampers in the beam-column joints, recently proposed and patented. The joint continuity allows for an optimisation of the lateral load resist-ing system, reducing the size of the columns with respect to the classical precast frame structural arrangement with hinged joints, whilst protecting columns and beams from the large actions deriving from the classical moment-resisting cast-in-situ or partially precast technological solu-tions. After the complete detailed design of the case study building employing the 3 solutions described above, the precast dissipative one being designed with dynamic non-linear analysis, the results of an environmental impact analysis are compared and discussed, confirming a reduced environmental impact for the dissipative solution, with respect to both precast with hinged beam-column joints and moment-resisting cast-in-situ alternatives
Congenital Pyriform Sinus Fistula: Systematic Review and Proposal for Treatment Using a Novel Endoscopic Approach
The pyriform sinus fistula (PSF) is a congenital developmental defect of the third or fourth branchial pouch. It presents as acute inflammatory swelling of the neck with recurrent deep neck abscesses, recurrent neck cystic lesions or suppurative thyroiditis. The literature reports various surgical approaches to treat this condition in children. A systematic review of the literature related to management protocols for PSF was conducted and we report a case exemplifying treatment in our department. Traditionally, treatment for PSF has been open surgery; however, in the last few decades, the minimally invasive transoral endoscopic approach has gained in importance, demonstrating long-term outcomes comparable to open surgery and with lower morbidity, and it has now become the first-choice treatment. We further describe a case of PSF treated by a transoral endoscopic approach with electric cauterization, fibrin glue obliteration of the fistula and Polydimethylsiloxane (Vox-Implants®, Bioplasty, Geleen, The Netherlands) submucosal injection. According to the authors, application of Vox-Implants® injection, in addition to standard techniques, may be helpful to reduce fistula recurrence rate after surgery
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