542 research outputs found
Social learning against data falsification in sensor networks
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.
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
Topological and subsystem codes on low-degree graphs with flag qubits
In this work we introduce two code families, which we call the heavy hexagon
code and heavy square code. Both code families are implemented by assigning
physical data and ancilla qubits to both vertices and edges of low degree
graphs. Such a layout is particularly suitable for superconducting qubit
architectures to minimize frequency collisions and crosstalk. In some cases,
frequency collisions can be reduced by several orders of magnitude. The heavy
hexagon code is a hybrid surface/Bacon-Shor code mapped onto a (heavy)
hexagonal lattice whereas the heavy square code is the surface code mapped onto
a (heavy) square lattice. In both cases, the lattice includes all the ancilla
qubits required for fault-tolerant error-correction. Naively, the limited qubit
connectivity might be thought to limit the error-correcting capability of the
code to less than its full distance. Therefore, essential to our construction
is the use of flag qubits. We modify minimum weight perfect matching decoding
to efficiently and scalably incorporate information from measurements of the
flag qubits and correct up to the full code distance while respecting the
limited connectivity. Simulations show that high threshold values for both
codes can be obtained using our decoding protocol. Further, our decoding scheme
can be adapted to other topological code families.Comment: 20 pages, 21 figures, Comments welcome! V2 conforms to journal
specification
Total Synthesis of Clavatadine A
The first total synthesis of the potent and selective human blood coagulation factor XIa inhibitor clavatadine A (1) is described. Direct, early-stage guanidinylation enabled rapid, convergent access to an immediate clavatadine A precursor. Concomitant lactone hydrolysis and guanidine deprotection with aqueous acid cleanly provided clavatadine A (1) in only four steps (longest linear sequence, 41–43% overall yield)
Imaging of joints with laser‐based photoacoustic tomography: An animal study
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134964/1/mp4166.pd
Coming Out to Care: Caregivers of Gay and Lesbian Seniors in Canada
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
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
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
- …