9,967 research outputs found
Influenza Evolution and H3N2 Vaccine Effectiveness, with Application to the 2014/2015 Season
Influenza A is a serious disease that causes significant morbidity and
mortality, and vaccines against the seasonal influenza disease are of variable
effectiveness. In this paper, we discuss use of the method to
predict the dominant influenza strain and the expected vaccine effectiveness in
the coming flu season. We illustrate how the effectiveness of the 2014/2015
A/Texas/50/2012 [clade 3C.1] vaccine against the A/California/02/2014 [clade
3C.3a] strain that emerged in the population can be estimated via pepitope. In
addition, we show by a multidimensional scaling analysis of data collected
through 2014, the emergence of a new A/New Mexico/11/2014-like cluster [clade
3C.2a] that is immunologically distinct from the A/California/02/2014-like
strains.Comment: 19 pages, 4 figure
Dynamical Properties of Multi-Armed Global Spirals in Rayleigh-Benard Convection
Explicit formulas for the rotation frequency and the long-wavenumber
diffusion coefficients of global spirals with arms in Rayleigh-Benard
convection are obtained. Global spirals and parallel rolls share exactly the
same Eckhaus, zigzag and skewed-varicose instability boundaries. Global spirals
seem not to have a characteristic frequency or a typical size ,
but their product is a constant under given experimental
conditions. The ratio of the radii of any two dislocations (,
) inside a multi-armed spiral is also predicted to be constant. Some of
these results have been tested by our numerical work.Comment: To appear in Phys. Rev. E as Rapid Communication
Use of Devolved Controllers in Data Center Networks
In a data center network, for example, it is quite often to use controllers
to manage resources in a centralized man- ner. Centralized control, however,
imposes a scalability problem. In this paper, we investigate the use of
multiple independent controllers instead of a single omniscient controller to
manage resources. Each controller looks after a portion of the network only,
but they together cover the whole network. This therefore solves the
scalability problem. We use flow allocation as an example to see how this
approach can manage the bandwidth use in a distributed manner. The focus is on
how to assign components of a network to the controllers so that (1) each
controller only need to look after a small part of the network but (2) there is
at least one controller that can answer any request. We outline a way to
configure the controllers to fulfill these requirements as a proof that the use
of devolved controllers is possible. We also discuss several issues related to
such implementation.Comment: Appears in INFOCOM 2011 Cloud Computing Worksho
Exactly Solvable Points and Symmetry-Protected Topological Phases of Quantum Spins on a Zig-Zag Lattice
A large number of symmetry-protected topological (SPT) phases have been
hypothesized for strongly interacting spin-1/2 systems in one dimension.
Realizing these SPT phases, however, often demands fine-tunings hard to reach
experimentally. And the lack of analytical solutions hinders the understanding
of their many-body wave functions. Here we show that two kinds of SPT phases
naturally arise for ultracold polar molecules confined in a zigzag optical
lattice. This system, motivated by recent experiments, is described by a spin
model whose exchange couplings can be tuned by an external field to reach
parameter regions not studied before for spin chains or ladders. Within the
enlarged parameter space, we find the ground state wave function can be
obtained exactly along a line and at a special point, for these two phases
respectively. These exact solutions provide a clear physical picture for the
SPT phases and their edge excitations. We further obtain the phase diagram by
using infinite time-evolving block decimation, and discuss the phase
transitions between the two SPT phases and their experimental signatures.Comment: 5+7 pages, 3+5 figure
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