270 research outputs found
Parafermionic quasi-particle basis and fermionic-type characters
A new basis of states for highest-weight modules in \ZZ_k parafermionic
conformal theories is displayed. It is formulated in terms of an effective
exclusion principle constraining strings of fundamental parafermionic
modes. The states of a module are then built by a simple filling process, with
no singular-vector subtractions. That results in fermionic-sum representations
of the characters, which are exactly the Lepowsky-Primc expressions. We also
stress that the underlying combinatorics -- which is the one pertaining to the
Andrews-Gordon identities -- has a remarkably natural parafermionic
interpretation.Comment: minor modifications and proof in app. C completed; 34 pages (harvmac
b
Genome-wide introgression among distantly related Heliconius butterfly species
Background: Although hybridization is thought to be relatively rare in animals, the raw genetic material introduced via introgression may play an important role in fueling adaptation and adaptive radiation. The butterfly genus Heliconius is an excellent system to study hybridization and introgression but most studies have focused on closely related species such as H. cydno and H. melpomene. Here we characterize genome-wide patterns of introgression between H. besckei, the only species with a red and yellow banded 'postman' wing pattern in the tiger-striped silvaniform clade, and co-mimetic H. melpomene nanna. Results: We find a pronounced signature of putative introgression from H. melpomene into H. besckei in the genomic region upstream of the gene optix, known to control red wing patterning, suggesting adaptive introgression of wing pattern mimicry between these two distantly related species. At least 39 additional genomic regions show signals of introgression as strong or stronger than this mimicry locus. Gene flow has been on-going, with evidence of gene exchange at multiple time points, and bidirectional, moving from the melpomene to the silvaniform clade and vice versa. The history of gene exchange has also been complex, with contributions from multiple silvaniform species in addition to H. besckei. We also detect a signature of ancient introgression of the entire Z chromosome between the silvaniform and melpomene/cydno clades. Conclusions: Our study provides a genome-wide portrait of introgression between distantly related butterfly species. We further propose a comprehensive and efficient workflow for gene flow identification in genomic data sets
Computation using Noise-based Logic: Efficient String Verification over a Slow Communication Channel
Utilizing the hyperspace of noise-based logic, we show two string
verification methods with low communication complexity. One of them is based on
continuum noise-based logic. The other one utilizes noise-based logic with
random telegraph signals where a mathematical analysis of the error probability
is also given. The last operation can also be interpreted as computing
universal hash functions with noise-based logic and using them for string
comparison. To find out with 10^-25 error probability that two strings with
arbitrary length are different (this value is similar to the error probability
of an idealistic gate in today's computer) Alice and Bob need to compare only
83 bits of the noise-based hyperspace.Comment: Accepted for publication in European Journal of Physics B (November
10, 2010
Fermionic solution of the Andrews-Baxter-Forrester model II: proof of Melzer's polynomial identities
We compute the one-dimensional configuration sums of the ABF model using the
fermionic technique introduced in part I of this paper. Combined with the
results of Andrews, Baxter and Forrester, we find proof of polynomial
identities for finitizations of the Virasoro characters
as conjectured by Melzer. In the thermodynamic limit
these identities reproduce Rogers--Ramanujan type identities for the unitary
minimal Virasoro characters, conjectured by the Stony Brook group. We also
present a list of additional Virasoro character identities which follow from
our proof of Melzer's identities and application of Bailey's lemma.Comment: 28 pages, Latex, 7 Postscript figure
Study of the Hindrance Effect in Sub-barrier Fusion Reactions
We have measured the fusion cross sections of the 12C(13C, p)24Na reaction
through off-line measurement of the beta-decay of 24Na using the beta-gamma
coincidence method. Our new measurements in the energy range of Ec.m. = 2.6-3.0
MeV do not show an obvious S-factor maximum but a plateau. Comparison between
this work and various models is presented.Comment: 3 pages, 3 figures, Talk at the "10th International Conference on
Nucleus-Nucleus Collisions", Beijing, 16-21 August 200
Polynomial Identities, Indices, and Duality for the N=1 Superconformal Model SM(2,4\nu)
We prove polynomial identities for the N=1 superconformal model SM(2,4\nu)
which generalize and extend the known Fermi/Bose character identities. Our
proof uses the q-trinomial coefficients of Andrews and Baxter on the bosonic
side and a recently introduced very general method of producing recursion
relations for q-series on the fermionic side. We use these polynomials to
demonstrate a dual relation under q \rightarrow q^{-1} between SM(2,4\nu) and
M(2\nu-1,4\nu). We also introduce a generalization of the Witten index which is
expressible in terms of the Rogers false theta functions.Comment: 41 pages, harvmac, no figures; new identities, proofs and comments
added; misprints eliminate
Integrating ecology into macroevolutionary research
On 9 March, over 150 biologists gathered in London for the Centre for Ecology and Evolution spring symposium, ‘Integrating Ecology into Macroevolutionary Research’. The event brought together researchers from London-based institutions alongside others from across the UK, Europe and North America for a day of talks. The meeting highlighted methodological advances and recent analyses of exemplar datasets focusing on the exploration of the role of ecological processes in shaping macroevolutionary patterns
Cost-effectiveness analysis of rFVIIIFc versus contemporary rFVIII treatments for patients with severe hemophilia A without inhibitors in the United States
Background
A range of treatments for patients with severe hemophilia A (HA) have been developed over the last decade, allowing for reduced frequency of administration and improved outcomes (joint health and breakthrough bleeding rates). While clinically effective, the cost effectiveness of these treatments has not been established.
Objective
This study presents a cost-effectiveness analysis of contemporary rFVIII treatments for severe HA patients without inhibitors.
Methods
A published semi-Markov model was used to compare three different prophylaxis regimens: (1) extended half-life (EHL) recombinant Factor VIII (rFVIII) Fc-fusion protein (rFVIIIFc, Eloctate®, Sanofi), (2) EHL PEGylated rFVIII (PEG-rFVIII, Adynovate®, Takeda), and (3) standard half-life (SHL) rFVIII (antihemophilic factor [recombinant], Advate®, Takeda), used as a proxy for all SHL rFVIII treatments. Acquisition costs were included based on published dosing and weight data. Benefits were incorporated through published annualized bleeding rates, rates of target joint development/resolution, and improvements in the modified hemophilia joint health score. Results were presented as total, discounted costs, and quality-adjusted life-years (QALYs).
Results
rFVIIIFc was shown to provide the most QALYs (27.922) compared with both PEG-rFVIII (27.454) and SHL rFVIII (27.071), at lower costs. Discounted lifetime costs were estimated at US20.198m (PEG-rFVIII), and US$18.285m (SHL rFVIII), and were predominantly affected by model settings related to acquisition costs, patient weight, and dosing.
Conclusions
rFVIIIFc may offer a cost-effective option for severe HA patients. Uncertainties owing to the limited evidence base is the main limitation of the study
Fusion cross sections for 6,7Li + 24Mg reactions at energies below and above the barrier
Measurement of fusion cross sections for the 6,7Li + 24Mg reactions by the
characteristic gamma-ray method has been done at energies from below to well
above the respective Coulomb barriers. The fusion cross sections obtained from
these gamma-ray cross sections for the two systems are found to agree well with
the total reaction cross sections at low energies. The decrease of fusion cross
sections with increase of energy is consistent with the fact that other
channels, in particular breakup open up with increase of bombarding energy.
This shows that there is neither inhibition nor enhancement of fusion cross
sections for these systems at above or below the barrier. The critical angular
momenta (lcr) deduced from the fusion cross sections are found to have an
energy dependence similar to other Li - induced reactions.Comment: 1 .pdf fil
sl(N) Onsager's Algebra and Integrability
We define an analog of Onsager's Algebra through a finite set of
relations that generalize the Dolan Grady defining relations for the original
Onsager's Algebra. This infinite-dimensional Lie Algebra is shown to be
isomorphic to a fixed point subalgebra of Loop Algebra with respect
to a certain involution. As the consequence of the generalized Dolan Grady
relations a Hamiltonian linear in the generators of Onsager's Algebra
is shown to posses an infinite number of mutually commuting integrals of
motion
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