1,249 research outputs found
Accuracy threshold for concatenated error detection in one dimension
Estimates of the quantum accuracy threshold often tacitly assume that it is
possible to interact arbitrary pairs of qubits in a quantum computer with a
failure rate that is independent of the distance between them. None of the many
physical systems that are candidates for quantum computing possess this
property. Here we study the performance of a concatenated error-detection code
in a system that permits only nearest-neighbor interactions in one dimension.
We make use of a new message-passing scheme that maximizes the number of errors
that can be reliably corrected by the code. Our numerical results indicate that
arbitrarily accurate universal quantum computation is possible if the
probability of failure of each elementary physical operation is below
approximately 10^{-5}. This threshold is three orders of magnitude lower than
the highest known.Comment: 7 pages, 4 figures, now with error bar
Message passing in fault tolerant quantum error correction
Inspired by Knill's scheme for message passing error detection, here we
develop a scheme for message passing error correction for the nine-qubit
Bacon-Shor code. We show that for two levels of concatenated error correction,
where classical information obtained at the first level is used to help
interpret the syndrome at the second level, our scheme will correct all cases
with four physical errors. This results in a reduction of the logical failure
rate relative to conventional error correction by a factor proportional to the
reciprocal of the physical error rate.Comment: 8 pages, 9 figure
Worldwide Diaspora of Aethina tumida (Coleoptera: Nitidulidae), a Nest Parasite of Honey Bees
Native to sub-Saharan Africa, Aethina tumida Murray (Coleoptera: Nitidulidae) is now an invasive pest of honey bee, Apis mellifera L., colonies in Australia and North America. Knowledge about the introduction(s) of this beetle from Africa into and among the current ranges will elucidate pest populations and invasion pathways and contribute to knowledge of how a parasite expands in new populations. We examined genetic variation in adult beetle samples from the United States, Australia, Canada, and Africa by sequencing a 912-base pair region of the mitochondrial DNA cytochrome c oxidase subunit I gene and screening 10 informative microsatellite loci. One Canadian introduction of small hive beetles can be traced to Australia, whereas the second introduction seems to have come from the United States. Beetles now resident in Australia were of a different African origin than were beetles in North America. North American beetles did not show covariance between two mitochondrial haplotypes and their microsatellite frequencies, suggesting that these beetles have a shared source despite having initial genetic structure within their introduced range. Excellent dispersal of beetles, aided in some cases by migratory beekeeping and the bee trade, seems to lead to panmixis in the introduced populations as well as in Afric
Promiscuous Feeding Across Multiple Honey Bee Hosts Amplifies the Vectorial Capacity of \u3ci\u3eVarroa destructor\u3c/i\u3e
Varroa destructor is a cosmopolitan pest and leading cause of colony loss of the European honey bee. Historically described as a competent vector of honey bee viruses, this arthropod vector is the cause of a global pandemic of Deformed wing virus, now endemic in honeybee populations in all Varroa-infested regions. Our work shows that viral spread is driven by Varroa actively switching from one adult bee to another as they feed. Assays using fluorescent microspheres were used to indicate the movement of fluids in both directions between host and vector when Varroa feed. Therefore, Varroa could be in either an infectious or naïve state dependent upon the disease status of their host. We tested this and confirmed that the relative risk of a Varroa feeding depended on their previous host’s infectiousness. Varroa exhibit remarkable heterogeneity in their host-switching behavior, with some Varroa infrequently switching while others switch at least daily. As a result, relatively few of the most active Varroa parasitize the majority of bees. This multiple-feeding behavior has analogs in vectorial capacity models of other systems, where promiscuous feeding by individual vectors is a leading driver of vectorial capacity. We propose that the honeybee-Varroa relationship offers a unique opportunity to apply principles of vectorial capacity to a social organism, as virus transmission is both vectored and occurs through multiple host-to-host routes common to a crowded society
Dynamics of the chiral phase transition from AdS/CFT duality
We use Lorentzian signature AdS/CFT duality to study a first order phase
transition in strongly coupled gauge theories which is akin to the chiral phase
transition in QCD. We discuss the relation between the latent heat and the
energy (suitably defined) of the component of a D-brane which lies behind the
horizon at the critical temperature. A numerical simulation of a dynamical
phase transition in an expanding, cooling Quark-Gluon plasma produced in a
relativistic collision is carried out.Comment: 30 pages, 5 figure
Baseline Needs Assessment for a Hospital-Based Violence Intervention Program 1-Year Pilot
The objectives of the present study were to measure and describe the baseline participant needs of a hospital-based violence intervention 1-year pilot program, assess differences in expected hospital revenue based on changes in health insurance coverage resulting from program implementation and discuss the program’s limitations. Methods: Between September 2020 and September 2021 Encompass Omaha enrolled 36 participants. A content analysis of 1199 progress notes detailing points of contact with participants was performed to determine goal status. Goals were categorized and goal status was defined as met, in process, dropped, or participant refusal. Results: The most frequently identified needs were help obtaining short-term disability assistance or completing FMLA paperwork (86.11%), immediate financial aid (86.11%), legal aid (83.33%), access to food (83.3%), and navigating medical issues other than the primary reason for hospitalization (83.33%). Conclusions: Meeting the participants’ short-term needs is critical for maintaining their engagement in the long-term. Further, differences in expected hospital revenue for pilot participants compared with a control group were examined, and this analysis found a reduction in medical and facility costs for program participants. The pilot stage highlighted how complex the needs and treatment of victims of violence are. As the program grows and its staff become more knowledgeable about social work, treatment, and resource access processes, the program will continue to improve
Deterministic optical quantum computer using photonic modules
The optical quantum computer is one of the few experimental systems to have
demonstrated small scale quantum information processing. Making use of cavity
quantum electrodynamics approaches to operator measurements, we detail an
optical network for the deterministic preparation of arbitrarily large
two-dimensional cluster states. We show that this network can form the basis of
a large scale deterministic optical quantum computer that can be fabricated
entirely on chip.Comment: 9 pages, 10 figures, minor revision
Identifying Overlapping and Hierarchical Thematic Structures in Networks of Scholarly Papers: A Comparison of Three Approaches
We implemented three recently proposed approaches to the identification of
overlapping and hierarchical substructures in graphs and applied the
corresponding algorithms to a network of 492 information-science papers coupled
via their cited sources. The thematic substructures obtained and overlaps
produced by the three hierarchical cluster algorithms were compared to a
content-based categorisation, which we based on the interpretation of titles
and keywords. We defined sets of papers dealing with three topics located on
different levels of aggregation: h-index, webometrics, and bibliometrics. We
identified these topics with branches in the dendrograms produced by the three
cluster algorithms and compared the overlapping topics they detected with one
another and with the three pre-defined paper sets. We discuss the advantages
and drawbacks of applying the three approaches to paper networks in research
fields.Comment: 18 pages, 9 figure
The role of scoping reviews in guideline development.
Systematic reviews have long been seen as critical in the development of trustworthy guidelines. However, as newer synthesis methodologies such as scoping reviews become more common, there is a need to discuss the potential role of these methodologies within guideline development. This article aims to summarize and provide examples of the role of scoping reviews in guideline development. Drawing on the expertise of the JBI scoping review group and guideline developers, this discussion article summarizes five key roles of scoping reviews in guideline development. Guideline developers can consider using scoping reviews when they need to: 1) know what existing guidelines could be adopted, adapted or adoloped; 2) understand the breadth of evidence that exists on a particular issue and help with the development and prioritization of questions, or identify previous systematic reviews; 3) identify contextual factors and information relevant for a clinical practice recommendation; 4) identify potential strategies for implementation and monitoring and; 5) conduct evidence surveillance and living mapping approaches. Scoping reviews conducted and reported according to best-practice guidelines and standards can be used in conjunction with systematic reviews to support the work of guideline developers usefully
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