Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2020 ( 9 )

2019 ( 691 )

2018 ( 822 )

2017 ( 759 )

Custom range...

Search Results: 1 - 10 of 467467 matches for " Stefano A. Karoschitz "
All listed articles are free for downloading (OA Articles)
Page 1 /467467
Display every page Item
A New Technique for Mastopexy and Reduction Mammaplasty: The Rolling Bilateral Flap Technique  [PDF]
Stefano A. Karoschitz
Advances in Breast Cancer Research (ABCR) , 2016, DOI: 10.4236/abcr.2016.52008
Abstract: Background: Numerous techniques have been proposed as “gold standard” for mastopexy, as for reduction mammaplasty. The quality of the breast parenchyma should be a primary factor in selecting the most appropriate technique for an individual case. Objective: The article describes a simple technique that can be used either for mastopexy or for reduction mammaplasty, giving optimal breast shape and position. It is appropriate for patients having some degree of ptosis, and especially for those in whom the glandular component of the breast predominates. Methods: The technique entails elevating the entire dome of the breast, rolling it under, and then stitching the two halves of the breast parenchyma together (lateral and medial dermoglandular flaps), while the upper pedicle (a third dermoglandular flap) bearing the nipple areolar complex (NAC) severed from the two inferior flaps is attached as a cap. The result is a new and attractive shape of the underlying supporting “barrel”. The technique can be performed with the T scar or the vertical scar approach. Results: The procedure was applied for various indications on 45 patients aged 20 - 62 years. Good results were only achieved in 36 women with predominant glandular component. Nine patients with fatty breasts achieved unsatisfactory results (6 with T scar, 3 with vertical scar) and very poor breast projection. Conclusions: The best-suited candidates for the proposed technique for mastopexy or reduction mammaplasty are women in whom the glandular component of the breast predominates. This simple technique, applicable with either inverted T scar or vertical scar approaches, carries very low morbidity, affording an attractive profile, long-lasting results, and conserving the patient’s ability to breast feed.
La tavola rotonda di Società Internet: "Le evoluzioni tecnologiche di Internet: la ricerca come traino per la realizzazione della Società dell'Informazione"
A. Lazzaroni,Stefano Trumpy
Bollettino del CILEA , 2002, DOI: 10.1472/bc.v81ifebbraio.1090
Abstract: Il 25 gennaio 2002 Società Internet (Sezione Italiana di Internet Society) ha organizzato a Roma, presso la sede centrale del Consiglio Nazionale delle Ricerche, la tavola rotonda dal titolo: "Le evoluzioni tecnologiche di Internet: la ricerca come traino per la realizzazione della Societa' dell'Informazione". Nell'articolo una panoramica dei principali temi emersi.
Geometric Reheating after Inflation
Bruce A. Bassett,Stefano Liberati
Physics , 1997, DOI: 10.1103/PhysRevD.60.049902
Abstract: Inflationary reheating via resonant production of non-minimally coupled scalar particles with only gravitational coupling is shown to be extremely strong, exhibiting a negative coupling instability for $\xi < 0$ and a wide resonance decay for $\xi \gg 1$. Since non-minimal fields are generic after renormalisation in curved spacetime, this offers a new paradigm in reheating - one which naturally allows for efficient production of the massive bosons needed for GUT baryogenesis. We also show that both vector and tensor fields are produced resonantly during reheating, extending the previously known correspondences between bosonic fields of different spins during preheating.
Symmetry breaking and restoring wave transmission in diode-antidiode double chains
Stefano Lepri,Boris A. Malomed
Physics , 2013, DOI: 10.1103/PhysRevE.87.042903
Abstract: We introduce a system of two parallel-coupled discrete nonlinear Schroedinger (DNLS) inhomogeneous chains. Each one favors the unidirectional transmission of incident packets, in the opposite directions with respect to each other. Two different configurations of the diode-antidiode pair are considered, a ladder and a plaquette. They feature, respectively, the uniform transverse linear coupling, or the coupling limited to the central nonlinear segment of the system. In the case of weak linear coupling, the symmetry breaking is observed (i.e., the pair still features the diode behavior), while the moderately strong coupling restores the symmetry, making the transmission effectively bidirectional. In the case of the ladder, an oscillatory dependence of the transmission on the strength of the coupling is observed and qualitatively explained.
Theory of box-model hyperfine couplings and transport signatures of long-range nuclear-spin coherence in a quantum-dot spin valve
Stefano Chesi,W. A. Coish
Physics , 2015, DOI: 10.1103/PhysRevB.91.245306
Abstract: We have theoretically analyzed coherent nuclear-spin dynamics induced by electron transport through a quantum-dot spin valve. The hyperfine interaction between electron and nuclear spins in a quantum dot allows for the transfer of angular momentum from spin-polarized electrons injected from ferromagnetic or half-metal leads to the nuclear spin system under a finite voltage bias. Accounting for a local nuclear-spin dephasing process prevents the system from becoming stuck in collective dark states, allowing a large nuclear polarization to be built up in the long-time limit. After reaching a steady state, reversing the voltage bias induces a transient current response as the nuclear polarization is reversed. Long-range nuclear-spin coherence leads to a strong enhancement of spin-flip transition rates (by an amount proportional to the number of nuclear spins) and is revealed by an intense current burst, analogous to superradiant light emission. The crossover to a regime with incoherent spin flips occurs on a relatively long time scale, on the order of the single-nuclear-spin dephasing time, which can be much longer than the time scale for the superradiant current burst. This conclusion is confirmed through a general master equation. For the two limiting regimes (coherent/incoherent spin flips) the general master equation recovers our simpler treatment based on rate equations, but is also applicable at intermediate dephasing. Throughout this work we assume uniform hyperfine couplings, which yield the strongest coherent enhancement. We propose realistic strategies, based on isotopic modulation and wavefunction engineering in core-shell nanowires, to realize this analytically solvable "box-model" of hyperfine couplings.
On modulational instability and energy localization in anharmonic lattices at finite energy density
Yuriy A. Kosevich,Stefano Lepri
Physics , 1999, DOI: 10.1103/PhysRevB.61.299
Abstract: The localization of vibrational energy, induced by the modulational instability of the Brillouin-zone-boundary mode in a chain of classical anharmonic oscillators with finite initial energy density, is studied within a continuum theory. We describe the initial localization stage as a gas of envelope solitons and explain their merging, eventually leading to a single localized object containing a macroscopic fraction of the total energy of the lattice. The initial-energy-density dependences of all characteristic time scales of the soliton formation and merging are described analytically. Spatial power spectra are computed and used for the quantitative explanation of the numerical results.
Do As antisites destroy the ferromagnetism of (Ga,Mn)As?
Stefano Sanvito,Nicola A. Hill
Physics , 2000,
Abstract: The effect of the inclusion of As antisites in the diluted magnetic semiconductor (Ga,Mn)As is studied within density functional theory in the local spin density approximation. In the case of homogeneous distribution of Mn ions we find that the ferromagnetism is largely weakened by the presence of the antisites. This is due to compensation of the free holes which mediate the long range ferromagnetic order. In contrast, when two Mn ions are coupled through only one As ion, ferromagnetic and antiferromagnetic order compete. In this case the magnetic ground state depends on: i) the position of the As antisites relative to the Mn, and ii) the As antisite concentration. We explain our results using a model of competing antiferromagnetic super-exchange and ferromagnetic double-exchange via localized Zener carriers. The strong dependence of the ferromagnetic order on the microscopic configuration accounts for the large variation in experimental data
Can half metallic zincblende MnAs be grown?
Stefano Sanvito,Nicola A. Hill
Physics , 2000,
Abstract: In this paper we investigate theoretically the ground state NiAs-type structure of MnAs and we compare the magnetic and structural properties with an hypothetical zincblende structure. A zincblende structure can be obtained, in principle, from the diluted magnetic semiconductor Ga$_{1-x}$Mn$_x$As in the limit $x=1$. Using density functional calculations within the local spin-density approximation (LSDA), we show that the zincblende structure, although showing half metallic behavior which is very attractive for spintronics, can not be stabilized at equilibrium. We perform a tight-binding analysis of the Mn-As bond in the tetrahedral coordination to investigate the nature of the bonding in diluted magnetic semiconductors.
Ab-initio transport theory for digital ferromagnetic heterostructures
Stefano Sanvito,Nicola A. Hill
Physics , 2001, DOI: 10.1103/PhysRevLett.87.267202
Abstract: MnAs/GaAs superlattices, made by $\delta$-doping GaAs with Mn, are known as digital ferromagnetic heterostructures. Here we present a theoretical density functional study of the electronic, magnetic and transport properties of such heterostructures. In the absence of intrinsic donors these systems show an half metallic density of states, with an exchange interaction much stronger than that of a random alloy with the same Mn concentration. {\it Ab initio} ballistic transport calculations show that the carriers with energies close to the Fermi energy are strongly confined within a few monolayers around the MnAs plane. This strong confinement is responsible for the large exchange coupling. Therefore the system can be described as a two dimensional half metal with large conductance in the MnAs plane and small conductance in the perpendicular direction.
Hadronic gamma-rays from RX J1713.7-3946?
Stefano Gabici,Felix A. Aharonian
Physics , 2014, DOI: 10.1093/mnrasl/slu132
Abstract: RXJ1713.7-3946 is a key object to check the supernova remnant paradigm of the origin of Galactic cosmic rays. While the origin of its gamma-ray emission (hadronic versus leptonic) is still debated, the hard spectrum at GeV energies reported by the Fermi collaboration is generally interpreted as a strong argument in favor of a leptonic scenario. On the contrary, we show that hadronic interactions can naturally explain the gamma-ray spectrum if gas clumps are present in the supernova remnant shell. The absence of thermal X-rays from the remnant fits well within this scenario.
Page 1 /467467
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.