110 research outputs found
Explicit estimates on the measure of primary KAM tori
From KAM Theory it follows that the measure of phase points which do not lie
on Diophantine, Lagrangian, "primary" tori in a nearly--integrable,
real--analytic Hamiltonian system is , if
is the size of the perturbation. In this paper we discuss how the constant in
front of depends on the unperturbed system and in
particular on the phase--space domain
The spin-orbit resonances of the Solar system: A mathematical treatment matching physical data
In the mathematical framework of a restricted, slightly dissipative
spin-orbit model, we prove the existence of periodic orbits for astronomical
parameter values corresponding to all satellites of the Solar system observed
in exact spin-orbit resonance
Periodic orbits close to elliptic tori and applications to the three-body problem
We prove, under suitable non-resonance and non-degeneracy ``twist''
conditions, a Birkhoff-Lewis type result showing the existence of infinitely
many periodic solutions, with larger and larger minimal period, accumulating
onto elliptic invariant tori (of Hamiltonian systems). We prove the
applicability of this result to the spatial planetary three-body problem in the
small eccentricity-inclination regime. Furthermore, we find other periodic
orbits under some restrictions on the period and the masses of the ``planets''.
The proofs are based on averaging theory, KAM theory and variational methods.
(Supported by M.U.R.S.T. Variational Methods and Nonlinear Differential
Equations.
Global properties of generic real-analytic nearly-integrable Hamiltonian systems
We introduce a new class of generic real analytic potentials
on and study global analytic properties of natural
nearly-integrable Hamiltonians , with potential
, on the phase space
with a given ball in . The phase space can be
covered by three sets: a `non-resonant' set, which is filled up to an
exponentially small set of measure (where is the maximal size of
resonances considered) by primary maximal KAM tori; a `simply resonant set' of
measure and a third set of measure
which is `non perturbative', in the sense that the -dynamics on it can be
described by a natural system which is {\sl not} nearly-integrable. We then
focus on the simply resonant set -- the dynamics of which is particularly
interesting (e.g., for Arnol'd diffusion, or the existence of secondary tori)
-- and show that on such a set the secular (averaged) 1 degree-of-freedom
Hamiltonians (labelled by the resonance index ) can be put
into a universal form (which we call `Generic Standard Form'), whose main
analytic properties are controlled by {\sl only one parameter, which is uniform
in the resonance label }
On the measure of KAM tori in two degrees of freedom
A conjecture of Arnold, Kozlov and Neishtadt on the exponentially small
measure of the non-torus set in analytic systems with two degrees of freedom is
discussed
Retroviral Integrations in Gene Therapy Trials
γ-Retroviral and lentiviral vectors allow the permanent integration of a therapeutic transgene in target cells and have provided in the last decade a delivery platform for several successful gene therapy (GT) clinical approaches. However, the occurrence of adverse events due to insertional mutagenesis in GT treated patients poses a strong challenge to the scientific community to identify the mechanisms at the basis of vector-driven genotoxicity. Along the last decade, the study of retroviral integration sites became a fundamental tool to monitor vector–host interaction in patients overtime. This review is aimed at critically revising the data derived from insertional profiling, with a particular focus on the evidences collected from GT clinical trials. We discuss the controversies and open issues associated to the interpretation of integration site analysis during patient's follow up, with an update on the latest results derived from the use of high-throughput technologies. Finally, we provide a perspective on the future technical development and on the application of these studies to address broader biological questions, from basic virology to human hematopoiesis
KAM theory for the Hamiltonian derivative wave equation
We prove an infinite dimensional KAM theorem which implies the existence of
Cantor families of small-amplitude, reducible, elliptic, analytic, invariant
tori of Hamiltonian derivative wave equationsComment: 66 page
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