82 research outputs found
Ultraviolet Renormalization of the Nelson Hamiltonian through Functional Integration
Starting from the N-particle Nelson Hamiltonian defined by imposing an
ultraviolet cutoff, we perform ultraviolet renormalization by showing that in
the zero cutoff limit a self-adjoint operator exists after a logarithmically
divergent term is subtracted from the original Hamiltonian. We obtain this term
as the diagonal part of a pair interaction appearing in the density of a Gibbs
measure derived from the Feynman-Kac representation of the Hamiltonian. Also,
we show existence of a weak coupling limit of the renormalized Hamiltonian and
derive an effective Yukawa interaction potential between the particles.Comment: 28 pages, revision of section 2 and typos correcte
Flows driven by Banach space-valued rough paths
We show in this note how the machinery of C^1-approximate flows devised in
the work "Flows driven by rough paths", and applied there to reprove and extend
most of the results on Banach space-valued rough differential equations driven
by a finite dimensional rough path, can be used to deal with rough differential
equations driven by an infinite dimensional Banach space-valued weak geometric
Holder p-rough paths, for any p>2, giving back Lyons' theory in its full force
in a simple way.Comment: 8 page
Quenched central limit theorem for the stochastic heat equation in weak disorder
We continue with the study of the mollified stochastic heat equation in
given by with spatially
smoothened cylindrical Wiener process , whose (renormalized) Feynman-Kac
solution describes the partition function of the continuous directed polymer.
In an earlier work (\cite{MSZ16}), a phase transition was obtained, depending
on the value of in the limiting object of the smoothened solution
as the smoothing parameter This partition function
naturally defines a quenched polymer path measure and we prove that as long as
stays small enough while converges to a strictly
positive non-degenerate random variable, the distribution of the diffusively
rescaled Brownian path converges under the aforementioned polymer path measure
to standard Gaussian distribution.Comment: Minor revisio
NMR interaction studies of Neu5Ac-α-(2,6)-Gal-β-(1-4)-GlcNAc with influenza-virus hemagglutinin expressed in transfected human cells
The emergence of escape-mutants of influenza hemagglutinin (HA) following vaccination compels the yearly re-formulation of flu vaccines. Since binding the sialic acid receptor remains in all cases essential for infection, small-molecule inhibitors of HA binding to sialic acid could be interesting therapeutic complements or alternatives to immuno-prophylaxis in the control of flu epidemics. In this work, we made use of NMR spectroscopy to study the interaction between a derivative of sialic acid (the Neu5Ac-\u3b1-(2,6)-Gal-\u3b2-(1-4)-GlcNAc trisaccharide) and HAs (H1 and H5) from human and avian strains of influenza virus, directly expressed on the surface of stable transfected 293 T human cells. The HAs were shown to retain their native trimeric conformation and binding properties. Exploiting the magnetization transfer between the proteins and the ligand, we obtained evidence of the binding event and mapped the (non-identical) sugar epitopes recognized by the two HA species. The rapid and reliable method for screening sialic acid-related HA ligands we have developed could yield useful information for an efficient drug design
Malliavin calculus for fractional heat equation
In this article, we give some existence and smoothness results for the law of
the solution to a stochastic heat equation driven by a finite dimensional
fractional Brownian motion with Hurst parameter . Our results rely on
recent tools of Young integration for convolutional integrals combined with
stochastic analysis methods for the study of laws of random variables defined
on a Wiener space.Comment: Dedicated to David Nualart on occasion of his 60th birthda
On small time asymptotics for rough differential equations driven by fractional Brownian motions
We survey existing results concerning the study in small times of the density
of the solution of a rough differential equation driven by fractional Brownian
motions. We also slightly improve existing results and discuss some possible
applications to mathematical finance.Comment: This is a survey paper, submitted to proceedings in the memory of
Peter Laurenc
Long-Term Safety of Anti-TNF Adalimumab in HBc Antibody-Positive Psoriatic Arthritis Patients: A Retrospective Case Series of 8 Patients
Immunosuppressive drugs commonly used in the treatment of psoriatic arthritis make patients more susceptible to viral, bacterial, and fungal infections because of their mechanism of action. They not only increase the risk of new infections but also act altering the natural course of preexisting infections. While numerous data regarding the reactivation of tuberculosis infection are available in the literature, poor information about the risk of reactivation or exacerbation of hepatitis viruses B and C infections during treatment with biologics has been reported. Furthermore, reported series with biological therapy included short periods of followup, and therefore, they are not adequate to verify the risk of reactivation in the long-term treatment. Our study evaluated patients with a history of hepatitis B and psoriatic arthritis treated with adalimumab and monitored up to six years. During the observation period, treatment was effective and well tolerated in all patients, and liver function tests and viral load levels remained unchanged
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