114,983 research outputs found

### Polyelectrolyte Solutions with Multivalent Salts

We investigate the thermodynamic properties of a polyelectrolyte solution in
a presence of {\it multivalent} salts. The polyions are modeled as rigid
cylinders with the charge distributed uniformly along the major axis. The
solution, besides the polyions, contain monovalent and divalent counterions as
well as monovalent coions. The strong electrostatic attraction existing between
the polyions and the counterions results in formation of clusters consisting of
one polyion and a number of associated monovalent and divalent counterions. The
theory presented in the paper allows us to explicitly construct the Helmholtz
free energy of a polyelectrolyte solution. The characteristic cluster size, as
well as any other thermodynamic property can then be determined by an
appropriate operation on the free energy

### Complex Formation Between Polyelectrolytes and Ionic Surfactants

The interaction between polyelectrolyte and ionic surfactant is of great
importance in different areas of chemistry and biology. In this paper we
present a theory of polyelectrolyte ionic-surfactant solutions. The new theory
successfully explains the cooperative transition observed experimentally, in
which the condensed counterions are replaced by ionic-surfactants. The
transition is found to occur at surfactant densities much lower than those for
a similar transition in non-ionic polymer-surfactant solutions. Possible
application of DNA surfactant complex formation to polynucleotide delivery
systems is also mentioned.Comment: 5 pages, latex, 3 figure

### Rational acyclic resolutions

Let X be a compactum such that dim_Q X 1. We prove that there is a
Q-acyclic resolution r: Z-->X from a compactum Z of dim < n+1. This allows us
to give a complete description of all the cases when for a compactum X and an
abelian group G such that dim_G X 1 there is a G-acyclic resolution r:
Z-->X from a compactum Z of dim < n+1.Comment: Published by Algebraic and Geometric Topology at
http://www.maths.warwick.ac.uk/agt/AGTVol5/agt-5-12.abs.htm

### Maps to the projective plane

We prove the projective plane \rp^2 is an absolute extensor of a
finite-dimensional metric space $X$ if and only if the cohomological dimension
mod 2 of $X$ does not exceed 1. This solves one of the remaining difficult
problems (posed by A.N.Dranishnikov) in extension theory. One of the main tools
is the computation of the fundamental group of the function space
\Map(\rp^n,\rp^{n+1}) (based at inclusion) as being isomorphic to either
$\Z_4$ or $\Z_2\oplus\Z_2$ for $n\ge 1$. Double surgery and the above fact
yield the proof.Comment: 17 page

### Cost of Survival for Large Rapidity Gaps

In this talk, given at "RunII QCD and weak boson WS", we report on
calculations of the survival probability of the large rapidity gap (LRG)
processes and its energy behaviour.Comment: 4 pages, 3 figure

### Universal acyclic resolutions for arbitrary coefficient groups

We prove that for every compactum $X$ and every integer $n \geq 2$ there are
a compactum $Z$ of $\dim \leq n+1$ and a surjective $UV^{n-1}$-map r: Z \lo X
such that for every abelian group $G$ and every integer $k \geq 2$ such that
$\dim_G X \leq k \leq n$ we have $\dim_G Z \leq k$ and $r$ is $G$-acyclic

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