1,495 research outputs found
Developing Decentralised Resilience to Malicious Influence in Collective Perception Problem
In collective decision-making, designing algorithms that use only local
information to effect swarm-level behaviour is a non-trivial problem. We used
machine learning techniques to teach swarm members to map their local
perceptions of the environment to an optimal action. A curriculum inspired by
Machine Education approaches was designed to facilitate this learning process
and teach the members the skills required for optimal performance in the
collective perception problem. We extended upon previous approaches by creating
a curriculum that taught agents resilience to malicious influence. The
experimental results show that well-designed rules-based algorithms can produce
effective agents. When performing opinion fusion, we implemented decentralised
resilience by having agents dynamically weight received opinion. We found a
non-significant difference between constant and dynamic weights, suggesting
that momentum-based opinion fusion is perhaps already a resilience mechanism.Comment: 14 Pages, 14 Figure
First study of semileptonic decay form factors using NRQCD
We present a quenched calculation of the form factors of the semileptonic
weak decay with NRQCD heavy quark and Wilson
light quark on a lattice at . The form factors are
evaluated at six heavy quark masses, in the range of GeV.
dependence of matrix elements are investigated and compared with HQET
predictions. We observe clear signal for the form factors near ,
even at the -quark mass range. is compared with
based on the soft pion theorem and significant difference is
observed.Comment: 3 pages, 5 ps figures, uses espcrc2.sty and epsf.sty, Talk presented
at Lattice'9
Semileptonic Form Factors
I report the current status of the heavy-light decay constants, the bag
parameters and the semileptonic form factors. I compare the heavy-light decay
constants with Wilson-Wilson and clover-clover fermions. Systematic errors such
as scale setting and renormalization factors are also discussed. 1/M
dependences for the heavy-light semileptonic form factors near
with clover-clover and NRQCD-Wilson fermions are found to be small.Comment: 12 pgs. 15 figures. Talk presented at LATTICE9
Flavourful hadronic physics
We review theoretical approaches to form factors that arise in heavy-meson
decays and are hadronic expressions of non-perturbative QCD. After motivating
their origin in QCD factorisation, we retrace their evolution from quark-model
calculations to non-perturbative QCD techniques with an emphasis on
formulations of truncated heavy-light amplitudes based upon Dyson-Schwinger
equations. We compare model predictions exemplarily for the B\to\pi transition
form factor and discuss new results for the g_{D*D\pi} coupling in the hadronic
D* decay.Comment: Based on a talk given at Light Cone 2009: Relativistic Hadronic And
Particle Physics, 8-13 July 2009, Sao Jose dos Campos, Sao Paulo, Brazi
Partial and Incremental PCMH Practice Transformation: Implications for Quality and Costs
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102699/1/hesr12085.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/102699/2/hesr12085-sup-0002-AuthorMatrix.pd
vertex from QCD sum rules
The form factors and the coupling constant of the vertex are
calculated using the QCD sum rules method. Three point correlation functions
are computed considering both and mesons off-shell and, after an
extrapolation of the QCDSR results, we obtain the coupling constant of the
vertex. We study the uncertainties in our result by calculating a third form
factor obtained when the is the off-shell meson, considering other
acceptable structures and computing the variations of the sum rules'
parameters. The form factors obtained have different behaviors but their
simultaneous extrapolations reach to the same value of the coupling constant
. We compare our result with other theoretical
estimates.Comment: 11 pages, 11 figure
Decay constants, semi-leptonic and non-leptonic decays in a Bethe-Salpeter Model
We evaluate the decay constants for the B and mesons and the form factors
for the semileptonic decays of the B meson to and mesons in a
Bethe-Salpeter model. From data we extract from and from decays. The form factors are then used to obtain non-leptonic
decay partial widths for and in the
factorization approximation.Comment: 15 Pages, 3 Postscript figures (available also from [email protected]
Spin Interacting Fields and Heavy Baryon Chiral Perturbation Theory
We analyze the consistency of the Chiral Lagrangian approach to the
description of the spin 3/2 interacting theory. We argue that to lowest order
in the 1/m expansion, the formalism leads to the appropriated constraints and
the theory is free of the so called ``off shell" ambiguities.Comment: 12 pages, Late
Oropouche virus cases identified in Ecuador using an optimised qRT-PCR informed by metagenomic sequencing
Oropouche virus (OROV) is responsible for outbreaks of Oropouche fever in parts of South America. We recently identified and isolated OROV from a febrile Ecuadorian patient, however, a previously published qRT-PCR assay did not detect OROV in the patient sample. A primer mismatch to the Ecuadorian OROV lineage was identified from metagenomic sequencing data. We report the optimisation of an qRT-PCR assay for the Ecuadorian OROV lineage, which subsequently identified a further five cases in a cohort of 196 febrile patients. We isolated OROV via cell culture and developed an algorithmically-designed primer set for whole-genome amplification of the virus. Metagenomic sequencing of the patient samples provided OROV genome coverage ranging from 68-99%. The additional cases formed a single phylogenetic cluster together with the initial case. OROV should be considered as a differential diagnosis for Ecuadorian patients with febrile illness to avoid mis-diagnosis with other circulating pathogens
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