760 research outputs found
On the second homotopy group of
In our earlier paper (K. Eda, U. Karimov, and D. Repov\v{s}, \emph{A
construction of simply connected noncontractible cell-like two-dimensional
Peano continua}, Fund. Math. \textbf{195} (2007), 193--203) we introduced a
cone-like space . In the present note we establish some new algebraic
properties of
On Snake cones, Alternating cones and related constructions
We show that the Snake on a square is homotopy equivalent to the
space which was investigated in the previous work by Eda, Karimov and
Repov\vs. We also introduce related constructions and and
investigate homotopical differences between these four constructions. Finally,
we explicitly describe the second homology group of the Hawaiian tori wedge
A nonaspherical cell-like 2-dimensional simply connected continuum and related constructions
We prove the existence of a 2-dimensional nonaspherical simply connected
cell-like Peano continuum (the space itself was constructed in one of our
earlier papers). We also indicate some relations between this space and the
well-known Griffiths' space from the 1950's
Critical dynamics of phase transition driven by dichotomous Markov noise
An Ising spin system under the critical temperature driven by a dichotomous
Markov noise (magnetic field) with a finite correlation time is studied both
numerically and theoretically. The order parameter exhibits a transition
between two kinds of qualitatively different dynamics, symmetry-restoring and
symmetry-breaking motions, as the noise intensity is changed.
There exist regions called channels where the order parameter stays for a
long time slightly above its critical noise intensity. Developing a
phenomenological analysis of the dynamics, we investigate the distribution of
the passage time through the channels and the power spectrum of the order
parameter evolution. The results based on the phenomenological analysis turn
out to be in quite good agreement with those of the numerical simulation.Comment: 27 pages, 12 figure
On the singular homology of one class of simply-connected cell-like spaces
In our earlier papers we constructed examples of 2-dimensional nonaspherical
simply-connected cell-like Peano continua, called {\sl Snake space}. In the
sequel we introduced the functor defined on the category of all
spaces with base points and continuous mappings. For the circle , the
space is a Snake space. In the present paper we study the
higher-dimensional homology and homotopy properties of the spaces
for any path-connected compact spaces
Three DNA polymerases, recruited by different mechanisms, carry out NER repair synthesis in human cells
Nucleotide excision repair (NER) is the most versatile DNA repair system that deals with the major UV photoproducts in DNA, as well as many other DNA adducts. The early steps of NER are well understood, whereas the later steps of repair synthesis and ligation are not. In particular, which polymerases are definitely involved in repair synthesis and how they are recruited to the damaged sites has not yet been established. We report that, in human fibroblasts, approximately half of the repair synthesis requires both polκ and polδ, and both polymerases can be recovered in the same repair complexes. Polκ is recruited to repair sites by ubiquitinated PCNA and XRCC1 and polδ by the classical replication factor complex RFC1-RFC, together with a polymerase accessory factor, p66, and unmodified PCNA. The remaining repair synthesis is dependent on polɛ, recruitment of which is dependent on the alternative clamp loader CTF18-RFC
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