3,992 research outputs found

    An Integrated Platform for Differential Electrochemical and ISFET Sensing

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    A fully-integrated differential biosensing platform on CMOS is presented for miniaturized enzyme-based electrochemical sensing. It enables sensor background current elimination and consists of a differential sensor array and a differential readout IC (DiRIC). The sensor array includes a four-electrode sensor for amperometric electrochemical sensing, as well as a differential ISFET-based pH sensor to calibrate the biosensors. The ISFET is biased in weak inversion and co-designed with DiRIC to enable pH measurements from 1 to 14 with resolution of 0.1 pH. DiRIC enables differential current measurement in the range of ¿¿100 ¿¿A with more than 120dB dynamic range

    PPLN Waveguide for Quantum Communication

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    We report on energy-time and time-bin entangled photon-pair sources based on a periodically poled lithium niobate (PPLN) waveguide. Degenerate twin photons at 1314 nm wavelength are created by spontaneous parametric down-conversion and coupled into standard telecom fibers. Our PPLN waveguide features a very high conversion efficiency of about 10^(-6), roughly 4 orders of magnitude more than that obtained employing bulk crystals. Even if using low power laser diodes, this engenders a significant probability for creating two pairs at a time - an important advantage for some quantum communication protocols. We point out a simple means to characterize the pair creation probability in case of a pulsed pump. To investigate the quality of the entangled states, we perform photon-pair interference experiments, leading to visibilities of 97% for the case of energy-time entanglement and of 84% for the case of time-bin entanglement. Although the last figure must still be improved, these tests demonstrate the high potential of PPLN waveguide based sources to become a key element for future quantum communication schemesComment: 11 pages, 9 figures, submitted to the European Physical Journal D (special issue of the Quick conference

    RAPD markers in wild and cultivated Vitis vinifera

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    Some Vitis vinifera cultivars and V. vinifera ssp. silvestris individuals have been subjected to the RAPD analysis in order to estimate the genetic diversity existing within this germplasm. 44 decamer primers of arbitrary sequence have been used for PCR and reproducible band profiles have been obtained. The distribution of the individualized polymorphic DNA markers has not turned out to be different in a remarkable way between cultivated and wild grapevines but this RAPD approach provides for some characteristics useful to analyze genetic relationships even within the Vitis vinifera species

    Nature-Inspired Interconnects for Self-Assembled Large-Scale Network-on-Chip Designs

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    Future nano-scale electronics built up from an Avogadro number of components needs efficient, highly scalable, and robust means of communication in order to be competitive with traditional silicon approaches. In recent years, the Networks-on-Chip (NoC) paradigm emerged as a promising solution to interconnect challenges in silicon-based electronics. Current NoC architectures are either highly regular or fully customized, both of which represent implausible assumptions for emerging bottom-up self-assembled molecular electronics that are generally assumed to have a high degree of irregularity and imperfection. Here, we pragmatically and experimentally investigate important design trade-offs and properties of an irregular, abstract, yet physically plausible 3D small-world interconnect fabric that is inspired by modern network-on-chip paradigms. We vary the framework's key parameters, such as the connectivity, the number of switch nodes, the distribution of long- versus short-range connections, and measure the network's relevant communication characteristics. We further explore the robustness against link failures and the ability and efficiency to solve a simple toy problem, the synchronization task. The results confirm that (1) computation in irregular assemblies is a promising and disruptive computing paradigm for self-assembled nano-scale electronics and (2) that 3D small-world interconnect fabrics with a power-law decaying distribution of shortcut lengths are physically plausible and have major advantages over local 2D and 3D regular topologies

    Orbiting Resonances and Bound States in Molecular Scattering

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    A family of orbiting resonances in molecular scattering is globally described by using a single pole moving in the complex angular momentum plane. The extrapolation of this pole at negative energies gives the location of the bound states. Then a single pole trajectory, that connects a rotational band of bound states and orbiting resonances, is obtained. These complex angular momentum singularities are derived through a geometrical theory of the orbiting. The downward crossing of the phase-shifts through pi/2, due to the repulsive region of the molecular potential, is estimated by using a simple hard-core model. Some remarks about the difference between diffracted rays and orbiting are also given.Comment: 18 pages, 3 figures, to appear in Physical Review

    O uso de drogas e o recolhimento compulsório de crianças e adolescentes no Rio de Janeiro

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    O estudo de crianças e adolescentes em situação de rua que fazem uso de drogas é um tema causador de grandes debates e polêmicas não só entre os pesquisadores da área, mas perante a sociedade também. Temos ciência que a questão do consumo de drogas está atrelada a uma perspectiva histórica, levando em conta os processos que transformaram os hábitos da sociedade. Neste sentido, é importante ressaltar que as políticas públicas voltadas para esse público alvo ainda não foram e ainda não são eficazes o suficiente para dar conta da crescente demanda. Em torno dessa discussão, surge o enfrentamento de modelos de tratamentos baseados em métodos proibicionistas e outros dispostos a utilizar a redução de danos como forma de atenuar os riscos e respeitar a vontade do indivíduo. Em meio a isso, a Prefeitura da cidade do Rio de Janeiro, através do Protocolo do Serviço Especializado em Abordagem Social, autoriza a internação compulsória dessa parte da população. O trabalho tem como proposta discutir se esse método de abordagem tem uma lógica de proteção ou de higienização da cidade, visando contribuir para o debate que acerca o tema. Em torno disso, o objetivo é uma reflexão crítica sobre as práticas das políticas públicas para população de rua e usuária de drogas

    Polarization entangled photon-pair source based on quantum nonlinear photonics and interferometry

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    We present a versatile, high-brightness, guided-wave source of polarization entangled photons, emitted at a telecom wavelength. Photon-pairs are generated using an integrated type-0 nonlinear waveguide, and subsequently prepared in a polarization entangled state via a stabilized fiber interferometer. We show that the single photon emission wavelength can be tuned over more than 50 nm, whereas the single photon spectral bandwidth can be chosen at will over more than five orders of magnitude (from 25 MHz to 4 THz). Moreover, by performing entanglement analysis, we demonstrate a high degree of control of the quantum state via the violation of the Bell inequalities by more than 40 standard deviations. This makes this scheme suitable for a wide range of quantum optics experiments, ranging from fundamental research to quantum information applications. We report on details of the setup, as well as on the characterization of all included components, previously outlined in F. Kaiser et al. (2013 Laser Phys. Lett. 10, 045202).Comment: 16 pages, 7 figure

    Corrigendum: Effects of a 3-week inpatient multidisciplinary body weight reduction program on body composition and physical capabilities in adolescents and adults with obesity

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    A correction has been made to Funding. The correct Funding statement is: “Research funded by the Italian Ministry of Health.” The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated
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