2,625 research outputs found
Traces of Sobolev functions on regular surfaces in infinite dimensions
In a Banach space endowed with a nondegenerate Gaussian measure, we
consider Sobolev spaces of real functions defined in a sublevel set of a Sobolev nondegenerate function . We define
the traces at of the elements of for , as
elements of where is the surface measure of Feyel
and de La Pradelle. The range of the trace operator is contained in
for and even in under
further assumptions. If is a suitable halfspace, the range is characterized
as a sort of fractional Sobolev space at the boundary.
An important consequence of the general theory is an integration by parts
formula for Sobolev functions, which involves their traces at
Transition between immune and disease states in a cellular automaton model of clonal immune response
In this paper we extend the Celada-Seiden (CS) model of the humoral immune
response to include infectious virus and cytotoxic T lymphocytes (cellular
response). The response of the system to virus involves a competition between
the ability of the virus to kill the host cells and the host's ability to
eliminate the virus. We find two basins of attraction in the dynamics of this
system, one is identified with disease and the other with the immune state.
There is also an oscillating state that exists on the border of these two
stable states. Fluctuations in the population of virus or antibody can end the
oscillation and drive the system into one of the stable states. The
introduction of mechanisms of cross-regulation between the two responses can
bias the system towards one of them. We also study a mean field model, based on
coupled maps, to investigate virus-like infections. This simple model
reproduces the attractors for average populations observed in the cellular
automaton. All the dynamical behavior connected to spatial extension is lost,
as is the oscillating feature. Thus the mean field approximation introduced
with coupled maps destroys oscillations.Comment: 27 pages LaTeX + 7 Figures Postscrip
A contribution to the knowledge of the skin albuminose cells of Torpedo ocellata Raf [Riv.Istochim.norm.pat. 8 411-416, 1962]
Glandular cells, other than the mucous cells, have been described in the skin of various groups of fish (Teleosts, Ganoids, Selachii) and they have been called 'albuminose' by various authors. The authors propose to study the albuminose cells in the skin of Torpedo ocellata Raf. from a histochemical point of view. The albuminose cells have a complex morphological structure and a correspondingly complicated histochemical make-up. One must treat them as an example of cell with secretions of a particular type, which must and will be better incorporated when more is known of characteristics existent in other species
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