7,909 research outputs found

    Photonic circuits for generating modal, spectral, and polarization entanglement

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    We consider the design of photonic circuits that make use of Ti:LiNbO3_{3} diffused channel waveguides for generating photons with various combinations of modal, spectral, and polarization entanglement. Down-converted photon pairs are generated via spontaneous optical parametric down-conversion (SPDC) in a two-mode waveguide. We study a class of photonic circuits comprising: 1) a nonlinear periodically poled two-mode waveguide structure, 2) a set of single-mode and two-mode waveguide-based couplers arranged in such a way that they suitably separate the three photons comprising the SPDC process, and, for some applications, 3) a holographic Bragg grating that acts as a dichroic reflector. The first circuit produces frequency-degenerate down-converted photons, each with even spatial parity, in two separate single-mode waveguides. Changing the parameters of the elements allows this same circuit to produce two nondegenerate down-converted photons that are entangled in frequency or simultaneously entangled in frequency and polarization. The second photonic circuit is designed to produce modal entanglement by distinguishing the photons on the basis of their frequencies. A modified version of this circuit can be used to generate photons that are doubly entangled in mode number and polarization. The third photonic circuit is designed to manage dispersion by converting modal, spectral, and polarization entanglement into path entanglement

    Extracting Touristic Information from Online Image Collections

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    In this paper, we present a Geographical Information Retrieval system, which aims to automatically extract and analyze touristic information from photos of online image collections (in our case of study Flickr). Our system collect all the photos, and the related information, that are associated to a specific city. We then use Google Maps service to geolocate the retrieved photos, and finally we analyze geo-referenced data to obtain our goals: 1) determining and locating the most interesting places of the city, i.e. the most visited locations, and 2) reconstructing touristic routes of the users visiting the city. Information is filtered by using a set of constraints, which we apply to select only the users that reasonably are tourists visiting the city. Tests were performed on an Italian city, Palermo, that is rich in artistic and touristic attractions, but preliminary tests showed that our technique could successfully be applied to any city in the world with a reasonable number of touristic landmarks

    Multiparticle Quantum Superposition and Stimulated Entanglement by Parity Selective Amplification of Entangled States

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    A multiparticle quantum superposition state has been generated by a novel phase-selective parametric amplifier of an entangled two-photon state. This realization is expected to open a new field of investigations on the persistence of the validity of the standard quantum theory for systems of increasing complexity, in a quasi decoherence-free environment. Because of its nonlocal structure the new system is expected to play a relevant role in the modern endeavor on quantum information and in the basic physics of entanglement.Comment: 13 pages and 3 figure

    Testosterone insulin-like effects: an in vitro study on the short-term metabolic effects of testosterone in human skeletal muscle cells

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    Testosterone by promoting different metabolic pathways contributes to short-term homeostasis of skeletal muscle, the largest insulin-sensitive tissue and the primary site for insulin-stimulated glucose utilization. Despite evidences indicate a close relationship between testosterone and glucose metabolism, the molecular mechanisms responsible for a possible testosterone-mediated insulin-like effects on skeletal muscle are still unknown

    Hemoperitoneum following mild blunt abdominal trauma: First presentation of Crohn's disease

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    Introduction: Inflammatory bowel diseases are heterogeneous in their presentation. Crohn's disease (CD) has been described as an unusual cause of massive lower gastrointestinal bleeding. We present a patient with CD whose first presentation was hemoperitoneum following mild blunt abdominal trauma Case presentation: A 54-year-old woman came to the emergency room with a blunt abdominal trauma. The patient underwent an abdominal CT scan with i.v. contrast medium injection, which showed hemoperitoneum with stenotic strictures of the small bowel and active massive bleeding from ileocolic artery. The rapid anemia onset and the CT report induced us to perform blood transfusion and an emergency exploratory laparotomy. Histological examination of the resected terminal ileum revealed a Crohn's disease. Discussion: Crohn's disease has been associated with hemoperitoneum, but to date there is no exact protocol regarding treatment of massive hemorrhagic Crohn's disease, which is rare. A conservative approach with medical therapy has been suggested for initial treatment. However, if medical treatment fails or bleeding continues even with intervention, bowel resection through surgical therapy should be performed
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