484 research outputs found

    Social learning against data falsification in sensor networks

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    Sensor networks generate large amounts of geographically-distributed data. The conventional approach to exploit this data is to first gather it in a special node that then performs processing and inference. However, what happens if this node is destroyed, or even worst, if it is hijacked? To explore this problem, in this work we consider a smart attacker who can take control of critical nodes within the network and use them to inject false information. In order to face this critical security thread, we propose a novel scheme that enables data aggregation and decision-making over networks based on social learning, where the sensor nodes act resembling how agents make decisions in social networks. Our results suggest that social learning enables high network resilience, even when a significant portion of the nodes have been compromised by the attacker

    Emerging infectious disease issues in blood safety.

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    Improvements in donor screening and testing and viral inactivation of plasma derivatives together have resulted in substantial declines in transfusion-transmitted infections over the last two decades. Most recently, nucleic acid testing techniques have been developed to screen blood and plasma donations for evidence of very recent viral infections that could be missed by conventional serologic tests. Nonetheless, the blood supply remains vulnerable to new and reemerging infections. In recent years, numerous infectious agents found worldwide have been identified as potential threats to the blood supply. Several newly discovered hepatitis viruses and agents of transmissible spongiform encephalopathies present unique challenges in assessing possible risks they may pose to the safety of blood and plasma products

    Coming Out to Care: Caregivers of Gay and Lesbian Seniors in Canada

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    Purpose: This article reports on the findings of a study whose purpose was to explore the experiences of caregivers of gay and lesbian seniors living in the community and to identify issues that emerged from an exploration of access to and equity in health care services for these populations. Design and Methods: The study used a qualitative methodology based upon principles of grounded theory in which open-ended interviews were undertaken with 17 caregivers living in three different cities across Canada. Results: Findings indicated several critical themes, including the impact of felt and anticipated discrimination, complex processes of coming out, the role of caregivers, self-identification as a caregiver, and support. Implications:  We consider several recommendations for change in light of emerging themes, including expanding the definition of caregivers to be more inclusive of gay and lesbian realities, developing specialized services, and advocating to eliminate discrimination faced by these populations

    Real-Time Decoding for Fault-Tolerant Quantum Computing: Progress, Challenges and Outlook

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    Quantum computing is poised to solve practically useful problems which are computationally intractable for classical supercomputers. However, the current generation of quantum computers are limited by errors that may only partially be mitigated by developing higher-quality qubits. Quantum error correction (QEC) will thus be necessary to ensure fault tolerance. QEC protects the logical information by cyclically measuring syndrome information about the errors. An essential part of QEC is the decoder, which uses the syndrome to compute the likely effect of the errors on the logical degrees of freedom and provide a tentative correction. The decoder must be accurate, fast enough to keep pace with the QEC cycle (e.g., on a microsecond timescale for superconducting qubits) and with hard real-time system integration to support logical operations. As such, real-time decoding is essential to realize fault-tolerant quantum computing and to achieve quantum advantage. In this work, we highlight some of the key challenges facing the implementation of real-time decoders while providing a succinct summary of the progress to-date. Furthermore, we lay out our perspective for the future development and provide a possible roadmap for the field of real-time decoding in the next few years. As the quantum hardware is anticipated to scale up, this perspective article will provide a guidance for researchers, focusing on the most pressing issues in real-time decoding and facilitating the development of solutions across quantum and computer science

    CrO2: a self-doped double exchange ferromagnet

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    Band structure calculations of CrO2 carried out in the LSDA+U approach reveal a clear picture of the physics behind the metallic ferromagnetic properties. Arguments are presented that the metallic ferromagnetic oxide CrO2 belongs to a class of materials in which magnetic ordering exists due to double exchange (in this respect CrO2 turns out to be similar to the CMR manganates). It is concluded that CrO2 has small or even negative charge transfer gap which can result in self-doping. Certain experiments to check the proposed picture are suggested.Comment: 4 pages, 4 Figure

    Orbital character of O 2p unoccupied states near the Fermi level in CrO2

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    The orbital character, orientation, and magnetic polarization of the O 2pp unoccupied states near the Fermi level (EFE_F) in CrO2_2 was determined using polarization-dependent X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) from high-quality, single-crystal films. A sharp peak observed just above EFE_F is excited only by the electric field vector (E\bf E) normal to the tetragonal cc-axis, characteristic of a narrow band (\approx 0.7 eV bandwidth) constituted from O 2pp orbitals perpendicular to cc (O 2pyp_y) hybridized with Cr 3dxzyzd_{xz-yz} t2gt_{2g} states. By comparison with band-structure and configuration-interaction (CI) cluster calculations our results support a model of CrO2_2 as a half-metallic ferromagnet with large exchange-splitting energy (Δexchsplit\Delta_{exch-split} \approx 3.0 eV) and substantial correlation effects.Comment: 4 pages, 3 figures, accepted for publication in Phys. Rev. B Rapid Com
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