183 research outputs found

    Some considerations about reviewing and open-access in scientific publishing

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    Scientific research changed profoundly over the last 30 years, in all its aspects. Scientific publishing has changed as well, mainly because of the strong increased number of submitted papers and because of the appearance of Open Access journals and publishers. We propose some reflections on these issues.Comment: One new contribution has been added, now 22 page

    The authors' reply

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    We appreciate Dr West's comments on our paper1; he has given us the opportunity to clarify some points that seem unresolved

    Multivessel revascularisation in ST-elevation myocardial infarction: Too early to change the guidelines

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    Multivessel revascularisation in ST-elevation myocardial infarction: too early to change the guideline

    A Numerical Framework For Nonlinear Peridynamics On Two-dimensional Manifolds Based On Implicit P-(Ec)k Schemes

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    In this manuscript, an original numerical procedure for the nonlinear peridynamics on arbitrarily--shaped two-dimensional (2D) closed manifolds is proposed. When dealing with non parameterized 2D manifolds at the discrete scale, the problem of computing geodesic distances between two non-adjacent points arise. Here, a routing procedure is implemented for computing geodesic distances by re-interpreting the triangular computational mesh as a non-oriented graph; thus returning a suitable and general method. Moreover, the time integration of the peridynamics equation is demanded to a P-(EC)k^k formulation of the implicit β\beta-Newmark scheme. The convergence of the overall proposed procedure is questioned and rigorously proved. Its abilities and limitations are analyzed by simulating the evolution of a two-dimensional sphere. The performed numerical investigations are mainly motivated by the issues related to the insurgence of singularities in the evolution problem. The obtained results return an interesting picture of the role played by the nonlocal character of the integrodifferential equation in the intricate processes leading to the spontaneous formation of singularities in real materials

    Application of a new photocatalytic nanomaterial obtained by Pulse Laser Ablation for Polychrome Paintings Conservation: a feasibility study

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    This works aims to present a preliminary study about the application on painting of TiO2 nanoparticles for self-cleaning and protective purposes. We firstly assessed the photocatalytic activity of the TiO2 nanoparticles, obtained by Pulsed Laser Ablation, by the discoloration of dye. After, the colloidal dispersion is applied to painting samples prepared in laboratory, according to old recipes and using the most-used historical binders and pigments, in order to verify the cleaning efficiency by discoloration of the chromatic markers. The spectrophotometric analysis is performed studying the Spectral Reflectance Factor trend and the color coordinates

    Modal and Polarization Qubits in Ti:LiNbO3_3 Photonic Circuits for a Universal Quantum Logic Gate

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    Lithium niobate photonic circuits have the salutary property of permitting the generation, transmission, and processing of photons to be accommodated on a single chip. Compact photonic circuits such as these, with multiple components integrated on a single chip, are crucial for efficiently implementing quantum information processing schemes. We present a set of basic transformations that are useful for manipulating modal qubits in Ti:LiNbO3_3 photonic quantum circuits. These include the mode analyzer, a device that separates the even and odd components of a state into two separate spatial paths; the mode rotator, which rotates the state by an angle in mode space; and modal Pauli spin operators that effect related operations. We also describe the design of a deterministic, two-qubit, single-photon, CNOT gate, a key element in certain sets of universal quantum logic gates. It is implemented as a Ti:LiNbO3_3 photonic quantum circuit in which the polarization and mode number of a single photon serve as the control and target qubits, respectively. It is shown that the effects of dispersion in the CNOT circuit can be mitigated by augmenting it with an additional path. The performance of all of these components are confirmed by numerical simulations. The implementation of these transformations relies on selective and controllable power coupling among single- and two-mode waveguides, as well as the polarization sensitivity of the Pockels coefficients in LiNbO3_3

    Acute myocardial infarction with occlusion of all three main epicardial coronary arteries: When Mother Nature takes care more than physicians

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    Double-arterial coronary stent thrombosis in acute myocardial infarction (AMI) is an infrequent but severe complication, especially when the third main coronary artery is chronically occluded. The conus artery (CA) can serve as a major source of collateral when the left anterior descendent coronary artery (LAD) becomes obstructed. We report a case of a 48-year-old man presenting with AMI due to a very late double-arterial stent thrombosis (ST) following drug-eluting stent implantation and a chronic occlusion of LAD collateralized by a large anomalous CA, which provided for the entire vascularization of the coronary tree. © 2010 Springer

    Morphology and dynamics of Venus's southern polar vortex reveal a drifting circulation

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    This was a last-minute invited contribution to coincide with the publication of the article "Venus’s Southern Polar Vortex Reveals Precessing Circulation" in Science

    The Comparative Exploration of the Ice Giant Planets with Twin Spacecraft: Unveiling the History of our Solar System

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    In the course of the selection of the scientific themes for the second and third L-class missions of the Cosmic Vision 2015-2025 program of the European Space Agency, the exploration of the ice giant planets Uranus and Neptune was defined "a timely milestone, fully appropriate for an L class mission". Among the proposed scientific themes, we presented the scientific case of exploring both planets and their satellites in the framework of a single L-class mission and proposed a mission scenario that could allow to achieve this result. In this work we present an updated and more complete discussion of the scientific rationale and of the mission concept for a comparative exploration of the ice giant planets Uranus and Neptune and of their satellite systems with twin spacecraft. The first goal of comparatively studying these two similar yet extremely different systems is to shed new light on the ancient past of the Solar System and on the processes that shaped its formation and evolution. This, in turn, would reveal whether the Solar System and the very diverse extrasolar systems discovered so far all share a common origin or if different environments and mechanisms were responsible for their formation. A space mission to the ice giants would also open up the possibility to use Uranus and Neptune as templates in the study of one of the most abundant type of extrasolar planets in the galaxy. Finally, such a mission would allow a detailed study of the interplanetary and gravitational environments at a range of distances from the Sun poorly covered by direct exploration, improving the constraints on the fundamental theories of gravitation and on the behaviour of the solar wind and the interplanetary magnetic field.Comment: 29 pages, 4 figures; accepted for publication on the special issue "The outer Solar System X" of the journal Planetary and Space Science. This article presents an updated and expanded discussion of the white paper "The ODINUS Mission Concept" (arXiv:1402.2472) submitted in response to the ESA call for ideas for the scientific themes of the future L2 and L3 space mission
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