1,458 research outputs found

    Equilibrium and Disorder-induced behavior in Quantum Light-Matter Systems

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    We analyze equilibrium properties of coupled-doped cavities described by the Jaynes-Cummings- Hubbard Hamiltonian. In particular, we characterize the entanglement of the system in relation to the insulating-superfluid phase transition. We point out the existence of a crossover inside the superfluid phase of the system when the excitations change from polaritonic to purely photonic. Using an ensemble statistical approach for small systems and stochastic-mean-field theory for large systems we analyze static disorder of the characteristic parameters of the system and explore the ground state induced statistics. We report on a variety of glassy phases deriving from the hybrid statistics of the system. On-site strong disorder induces insulating behavior through two different mechanisms. For disorder in the light-matter detuning, low energy cavities dominate the statistics allowing the excitations to localize and bunch in such cavities. In the case of disorder in the light- matter coupling, sites with strong coupling between light and matter become very significant, which enhances the Mott-like insulating behavior. Inter-site (hopping) disorder induces fluidity and the dominant sites are strongly coupled to each other.Comment: about 10 pages, 12 figure

    Motor cortex stimulation for refractory demyelinating disease-associated trigeminal neuralgia

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    Patients with demyelinating diseases (DDs) such as multiple sclerosis have a 20-fold higher risk of developing trigeminal neuralgia (TN). DD-related TN is more frequently refractory to the usual medical and surgical treatment. We report the case of a 57-year-old man presenting to our neurology outpatient clinic with a 12-year history of medical and surgical refractory TN associated with demyelinating lesions on magnetic resonance imaging. After a new failure of pharmacological treatment with oxcarbazepine, pregabalin, baclofen, and duloxetine, motor cortex stimulation (MCS) was performed, and the patient remained mostly pain-free, without any pharmacological treatment during the 3.5 years of follow-up. MCS may be a useful approach for DD-related refractory TN, and further studies can clarify its role in TN management.publishersversionpublishe

    A simplification of rigorous atmospheric raytracing based on judicious rectilinear paths for near-surface GNSS reflectometry

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    Atmospheric delays are known to cause biases in Global Navigation Satellite System Reflectometry (GNSS-R) altimetry applications, such as for sea-level monitoring. The main quantity of interest is the reflection-minus-direct or interferometric atmospheric delay. Recently, we have presented a rigorous raytracing procedure to account for linear and angular refraction in conjunction with reflection as observed from near-surface platforms. Here, we demonstrate the feasibility of simplifying the ray trajectory by imposing a rectilinear wave propagation model. Two variants were assessed, based on the apparent or refracted satellite direction on the one hand and the geometric or vacuum conditions on the other hand. The former was shown to agree with rigorous results in terms of interferometric radio length while the latter agreed in terms of the interferometric vacuum distance. Upon a judicious combination of the best aspects of the two rectilinear cases, we have defined a mixed variant with excellent agreement with rigorous raytracing in terms of interferometric atmospheric delay. We further showed that mapping functions developed for GNSS positioning cannot be reused for GNSS-R purposes without adaptations. Otherwise, the total atmospheric delay may be underestimated by up to 50% at low elevation angles. The present work facilitates the adaptation of existing atmospheric raytracing software for GNSS-R purposes

    Evolutionary Dynamics of Multigene Families in Triportheus (Characiformes, Triportheidae): A Transposon Mediated Mechanism?

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    Triportheus (Characiformes, Triportheidae) is a freshwater fish genus with 18 valid species. These fishes are widely distributed in the major river drainages of South America, having commercial importance in the fishing market, mainly in the Amazon basin. This genus has diverged recently in a complex process of speciation carried out in different river basins. The use of repetitive sequences is suitable to trace the genomic reorganizations occured along the speciation process. In this work, the 5S rDNA multigene family has been characterized at molecular and phylogenetic level. The results showed that other multigene family has been found within the non-transcribed spacer (NTS): the U1 snRNA gene. Double-FISH with 5S and U1 probes were also performed, confirming the close linkage between these two multigene families. Moreover, evidences of different transposable elements (TE) were detected within the spacer, thus suggesting a transposon-mediated mechanism of 5S-U1 evolutionary pathway in this genus. Phylogenetic analysis demonstrated a species-specific grouping, except for Triportheus pantanensis, Triportheus aff. rotundatus and Triportheus trifurcatus. The evolutionary model of the 5S rDNA in Triportheus species has been discussed. In addition, the results suggest new clues for the speciation and evolutionary trend in these species, which could be suitable to use in other Characiformes species

    Extreme nonlocality with one photon

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    Quantum nonlocality is typically assigned to systems of two or more well separated particles, but nonlocality can also exist in systems consisting of just a single particle, when one considers the subsystems to be distant spatial field modes. Single particle nonlocality has been confirmed experimentally via a bipartite Bell inequality. In this paper, we introduce an N-party Hardy-like proof of impossibility of local elements of reality and a Bell inequality for local realistic theories for a single particle superposed symmetrical over N spatial field modes (i.e. a N qubit W state). We show that, in the limit of large N, the Hardy-like proof effectively becomes an all-versus nothing (or GHZ-like) proof, and the quantum-classical gap of the Bell inequality tends to be same of the one in a three-particle GHZ experiment. We detail how to test the nonlocality in realistic systems.Comment: 11 single column pages, 2 figures; v3 now includes a Bell inequality in addition to the results in the previous versio

    Innovating Management Control by Dynamic Analysis of Pareto in a Hotel Business

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    This paper deals with the Pareto Analysis of problems observed and criticized by clients in a hotel establishment in the municipality of Porto Velho, capital of the State of Rondocirc;nia. The general objective of the research is to study the use of Pareto Analysis in these problems that annoy the clients; (1), to group the data in descending order of frequency and to calculate the cumulative values (2), and indicating innovation for managerial control through a tool for Pareto Analysis in a dynamical way (3). The methodology of the qualitative-quantitative approach, of an exploratory nature, is adopted; the bibliographic survey and the field research are applied in support of the case study. Through the database system that the company under study possesses, the data necessary to be used in the Pareto Analysis are obtained, completing the first specific objective; the grouping of these data in descending order of absolute frequency, the calculation of the cumulative values, the preparation of the Pareto Diagram and the analysis carried out successfully completed the second specific objective; and finally the study is finished with the creation of a tool that allows a more dynamic analysis of the scenario in which the company is inserted, as a proposal of innovation for the institution to perform its practical and dynamic analyzes, useful in decision making. This study is a contribution of the academy to managers who work with complex decisions in hotel or related establishments interested in customer satisfaction

    3-Hydroxy-2-phenyl-2,3,3a,7a-tetrahydro-1H,5H-pyrano[3,2-b]pyrrol-5-one: crystal structure and Hirshfeld surface analysis

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    The title isoaltholactone derivative, C13H13NO3, has an NH group in place of the ether-O atom in the five-membered ring of the natural product. The five-membered ring is twisted about the N—C bond linking it to the six-membered ring, which has a half-chair conformation with the O atom connected to the ether-O atom lying above the plane defined by the remaining atoms. The dihedral angle between the mean planes of the rings comprising the fused-ring system is 75.10 (8)°. In the crystal, hydroxy-O—H...N(amine) hydrogen bonding sustains linear supramolecular chains along the a axis. Chains are linked into a three-dimensional architecture via amine-N—H...π(phenyl) and phenyl-C—H...O(hydroxy) interactions. The influence of the amine-N—H...π(phenyl) contact on the molecular packing is revealed by an analysis of the Hirshfeld surface
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