757 research outputs found

    Rubies : A Novelty Intermezzo Two-Step

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    https://digitalcommons.library.umaine.edu/mmb-ps/2910/thumbnail.jp

    Experimentally implementable criteria revealing substructures of genuine multipartite entanglement

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    We present a general framework that reveals substructures of genuine multipartite entanglement. Via simple inequalities it is possible to discriminate different sets of multipartite qubit states. These inequalities are beneficial regarding experimental examinations as only local measurements are required. Furthermore, the number of observables scales favorably with system size. In exemplary cases we demonstrate the noise resistance and discuss implementations.Comment: 14 pages, 4 figure

    Phonon-Assisted Two-Photon Interference from Remote Quantum Emitters

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    Photonic quantum technologies are on the verge offinding applications in everyday life with quantum cryptography andquantum simulators on the horizon. Extensive research has beencarried out to identify suitable quantum emitters and single epitaxialquantum dots have emerged as near-optimal sources of bright, on-demand, highly indistinguishable single photons and entangledphoton-pairs. In order to build up quantum networks, it is essentialto interface remote quantum emitters. However, this is still anoutstanding challenge, as the quantum states of dissimilar“artificialatoms”have to be prepared on-demand with highfidelity and thegenerated photons have to be made indistinguishable in all possibledegrees of freedom. Here, we overcome this major obstacle and show an unprecedented two-photon interference (visibility of 51±5%) from remote strain-tunable GaAs quantum dots emitting on-demand photon-pairs. We achieve this result by exploiting forthefirst time the full potential of a novel phonon-assisted two-photon excitation scheme, which allows for the generation ofhighly indistinguishable (visibility of 71±9%) entangled photon-pairs (fidelity of 90±2%), enables push-button biexciton statepreparation (fidelity of 80±2%) and outperforms conventional resonant two-photon excitation schemes in terms of robustnessagainst environmental decoherence. Our results mark an important milestone for the practical realization of quantum repeatersand complex multiphoton entanglement experiments involving dissimilar artificial atom

    Resonant Bend Loss in Leakage Channel Fibers

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    Leakage channel fibers, designed to suppress higher-order modes, demonstrate resonant power loss at certain critical radii of curvature. Outside the resonance, the power recovers to the levels offset by the usual mechanism of bend-induced loss. Using C2^2-imaging, we experimentally characterize this anomaly and identify the corresponding physical mechanism as the radiative decay of the fundamental mode mediated by the resonant coupling to a cladding mode.Comment: 3 pages, 4 figures, submitted to Optics Letter

    On semiclassical calculation of three-point functions in AdS_5 \times T^(1,1)

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    Recently there has been progress on the computation of two- and three-point correlation functions with two "heavy" states via semiclassical methods. We extend this analysis to the case of AdS_5 \times T^(1,1), and examine the suggested procedure for the case of several simple string solutions. By making use of AdS/CFT duality, we derive the relevant correlation functions of operators belonging to the dual gauge theory.Comment: 18 pages, added referenc

    Did Cryptic Invasion of North America by Common Reed Change Exposure to Pollen Allergens?

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    Common reed, Phragmites australis (reed), is a very tall grass that spread greatly to occupy large areas near many eastern North American cities over the past century. Its aerially dispersed pollen is known to incite allergic reactions, and possibly asthma, in some persons, but is not distinguished from that of any other grass in routine pollen monitoring. We hypothesize that this regional expansion by reed has increased late-season exposure to grass-pollen allergens in parts of these metropolitan areas. The information available indicates that reed's geographic location, high abundance, small pollen size, release of pollen relatively far above ground, substantial pollen productivity, pollen allergen composition, and late season of pollen release all point to its potential importance for a large number of persons whose health may be degraded by grass pollen. If the other common late-flowering grasses in the same area have larger pollen grains, it may be possible to visually distinguish reed pollen captured by monitoring devices. If not, ratios of stable isotopes of carbon in the pollen may permit differentiation. Otherwise, analytical techniques based on molecular differences need further development in order to estimate local population exposure to allergens from reed. Some 90 million North Americans may live close enough to large tracts of reed to be exposed to substantial concentrations of its pollen, so much more attention to this situation seems warranted. If reed pollen were found to be a health hazard for a particular metropolitan area, removal of the pollen sources may be more feasible than is the case for many other species

    Conflictos por encuadramiento sindical y/o convencional. El caso Camioneros-Tintoreros

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    El artículo estudia el conflicto por encuadramiento sindical y convencional entre el gremio de Camioneros y el de Tintoreros. La disputa se generó en torno a la representación de los trabajadores de la categoría choferes y ayudantes de carga, en la actividad de Lavaderos Industriales, de Ropa, Limpierías y Afines. La investigación analizó los procesos que llevaron a los trabajadores de la categoría disputada a exigir la continuidad de la tutela gremial y convencional bajo la órbita de Tintoreros. El método utilizado fue el estudio de caso. Los resultados muestran que los conflictos por encuadramiento sindical y/o convencional tensionan la representatividad gremial y la identidad colectiva.This article studies the conflict between Teamsters' and Dry Cleaners' Unions over representation of a particular group of workers. The struggle developed around union representation of drivers and load assistants into the Industrial Laundry sector. Our researcher analyzed the circumstances that led workers in this area to demand their continuity as entitled to Dry Cleaners' Union representation. We used case study as a method of research. The results show that such conflicts over trade union's representation strain both representativeness and collective identity.Fil: Pontoni, Gabriela A. Universidad Nacional de La Matanza; Argentina.Fil: Schimpf, María Belén. Universidad Nacional de La Matanza; Argentina

    In silico investigation of a KCNQ1 mutation associated with short QT syndrome

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    Short QT syndrome (SQTS) is a rare condition characterized by abnormally ‘short’ QT intervals on the ECG and increased susceptibility to cardiac arrhythmias and sudden death. This simulation study investigated arrhythmia dynamics in multi-scale human ventricle models associated with the SQT2-related V307L KCNQ1 ‘gain-of-function’ mutation, which increases slow-delayed rectifier potassium current (IKs). A Markov chain (MC) model recapitulating wild type (WT) and V307L mutant IKs kinetics was incorporated into a model of the human ventricular action potential (AP) for investigation of QT interval changes and arrhythmia substrates. In addition, the degree of simulated IKs inhibition necessary to normalize the QT interval and terminate re-entry in SQT2 conditions was quantified. The developed MC model accurately reproduced AP shortening and reduced effective refractory period associated with altered IKs kinetics in homozygous (V307L) and heterozygous (WT-V307L) mutation conditions, which increased the lifespan and dominant frequency of re-entry in 3D human ventricle models. IKs reductions of 58% and 65% were sufficient to terminate re-entry in WT-V307L and V307L conditions, respectively. This study further substantiates a causal link between the V307L KCNQ1 mutation and pro-arrhythmia in human ventricles, and establishes partial inhibition of IKs as a potential anti-arrhythmic strategy in SQT2

    Exploiting Term Hiding to Reduce Run-time Checking Overhead

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    One of the most attractive features of untyped languages is the flexibility in term creation and manipulation. However, with such power comes the responsibility of ensuring the correctness of these operations. A solution is adding run-time checks to the program via assertions, but this can introduce overheads that are in many cases impractical. While static analysis can greatly reduce such overheads, the gains depend strongly on the quality of the information inferred. Reusable libraries, i.e., library modules that are pre-compiled independently of the client, pose special challenges in this context. We propose a technique which takes advantage of module systems which can hide a selected set of functor symbols to significantly enrich the shape information that can be inferred for reusable libraries, as well as an improved run-time checking approach that leverages the proposed mechanisms to achieve large reductions in overhead, closer to those of static languages, even in the reusable-library context. While the approach is general and system-independent, we present it for concreteness in the context of the Ciao assertion language and combined static/dynamic checking framework. Our method maintains the full expressiveness of the assertion language in this context. In contrast to other approaches it does not introduce the need to switch the language to a (static) type system, which is known to change the semantics in languages like Prolog. We also study the approach experimentally and evaluate the overhead reduction achieved in the run-time checks.Comment: 26 pages, 10 figures, 2 tables; an extension of the paper version accepted to PADL'18 (includes proofs, extra figures and examples omitted due to space reasons
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