2,419 research outputs found
On the splitting-up method for rough (partial) differential equations
This article introduces the splitting method to systems responding to rough
paths as external stimuli. The focus is on nonlinear partial differential
equations with rough noise but we also cover rough differential equations.
Applications to stochastic partial differential equations arising in control
theory and nonlinear filtering are given
A generalized Fernique theorem and applications
We prove a generalisation of Fernique's theorem which applies to a class of
(measurable) functionals on abstract Wiener spaces by using the isoperimetric
inequality. Our motivation comes from rough path theory where one deals with
iterated integrals of Gaussian processes (which are generically not Gaussian).
Gaussian integrability with explicitly given constants for variation and
H\"older norms of the (fractional) Brownian rough path, Gaussian rough paths
and the Banach space valued Wiener process enhanced with its L\'evy area
[Ledoux, Lyons, Quian. "L\'evy area of Wiener processes in Banach spaces". Ann.
Probab., 30(2):546--578, 2002] then all follow from applying our main theorem.Comment: To be published in the Proceedings of the AMS
Effective incorporation of 2'-O-methyl-oligoribonucleotides into liposomes and enhanced cell association through modification with thiocholesterol
Cholesterol was linked to 2'-O-methyl-oligoribonucleotides (2'-OMe-RNA) via a disulfide bond by reacting the 3'-(pyridyldithio)-modified 2'-OMe-RNA with thiocholesterol in dichloromethane-methanol solution. This ligation reaction was made possible by a novel strategy in which the highly charged oligonucleotide was rendered soluble in nonaqueous solvent through conversion to a lipophilic amidinium salt. The biodegradable lipophilic modification of 2'-OMe-RNA resulted in a large increase in incorporation of such oligonucleotides into liposomes prepared by reversephase evaporation. Furthermore, association of these modified oligonucleotides with cultured TIB 73 cells was 100-fold higher than that seen with unmodified 2'-OMe-RNA in serum-free medium and about 10 to 30-fold higher in the presence of 10% calf serum. During incubation with cells, release of the internalized oligonucleotide from the thiocholesteryl moiety can be demonstrated
A Free Boundary Characterisation of the Root Barrier for Markov Processes
We study the existence, optimality, and construction of non-randomised
stopping times that solve the Skorokhod embedding problem (SEP) for Markov
processes which satisfy a duality assumption. These stopping times are hitting
times of space-time subsets, so-called Root barriers. Our main result is,
besides the existence and optimality, a potential-theoretic characterisation of
this Root barrier as a free boundary. If the generator of the Markov process is
sufficiently regular, this reduces to an obstacle PDE that has the Root barrier
as free boundary and thereby generalises previous results from one-dimensional
diffusions to Markov processes. However, our characterisation always applies
and allows, at least in principle, to compute the Root barrier by dynamic
programming, even when the well-posedness of the informally associated obstacle
PDE is not clear. Finally, we demonstrate the flexibility of our method by
replacing time by an additive functional in Root's construction. Already for
multi-dimensional Brownian motion this leads to new class of constructive
solutions of (SEP).Comment: 31 pages, 14 figure
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