3,174 research outputs found
Quasiperiodic graphs: structural design, scaling and entropic properties
A novel class of graphs, here named quasiperiodic, are constructed via
application of the Horizontal Visibility algorithm to the time series generated
along the quasiperiodic route to chaos. We show how the hierarchy of
mode-locked regions represented by the Farey tree is inherited by their
associated graphs. We are able to establish, via Renormalization Group (RG)
theory, the architecture of the quasiperiodic graphs produced by irrational
winding numbers with pure periodic continued fraction. And finally, we
demonstrate that the RG fixed-point degree distributions are recovered via
optimization of a suitably defined graph entropy
New invariants for entangled states
We propose new algebraic invariants that distinguish and classify entangled
states. Considering qubits as well as higher spin systems, we obtained complete
entanglement classifications for cases that were either unsolved or only
conjectured in the literature.Comment: published versio
Vector valued Macdonald polynomials
This paper defines and investigates nonsymmetric Macdonald polynomials with
values in an irreducible module of the Hecke algebra of type . These
polynomials appear as simultaneous eigenfunctions of Cherednik operators.
Several objects and properties are analyzed, such as the canonical bilinear
form which pairs polynomials with those arising from reciprocals of the
original parameters, and the symmetrization of the Macdonald polynomials. The
main tool of the study is the Yang-Baxter graph. We show that these Macdonald
polynomials can be easily computed following this graph. We give also an
interpretation of the symmetrization and the bilinear forms applied to the
Macdonald polynomials in terms of the Yang-Baxter graph.Comment: 85 pages, 5 figure
Why one-size-fits-all vaso-modulatory interventions fail to control glioma invasion: in silico insights
There is an ongoing debate on the therapeutic potential of vaso-modulatory
interventions against glioma invasion. Prominent vasculature-targeting
therapies involve functional tumour-associated blood vessel deterioration and
normalisation. The former aims at tumour infarction and nutrient deprivation
medi- ated by vascular targeting agents that induce occlusion/collapse of
tumour blood vessels. In contrast, the therapeutic intention of normalising the
abnormal structure and function of tumour vascular net- works, e.g. via
alleviating stress-induced vaso-occlusion, is to improve chemo-, immuno- and
radiation therapy efficacy. Although both strategies have shown therapeutic
potential, it remains unclear why they often fail to control glioma invasion
into the surrounding healthy brain tissue. To shed light on this issue, we
propose a mathematical model of glioma invasion focusing on the interplay
between the mi- gration/proliferation dichotomy (Go-or-Grow) of glioma cells
and modulations of the functional tumour vasculature. Vaso-modulatory
interventions are modelled by varying the degree of vaso-occlusion. We
discovered the existence of a critical cell proliferation/diffusion ratio that
separates glioma invasion re- sponses to vaso-modulatory interventions into two
distinct regimes. While for tumours, belonging to one regime, vascular
modulations reduce the tumour front speed and increase the infiltration width,
for those in the other regime the invasion speed increases and infiltration
width decreases. We show how these in silico findings can be used to guide
individualised approaches of vaso-modulatory treatment strategies and thereby
improve success rates
Modeling the chemical impact and the optical emissions produced by lightning-induced electromagnetic fields in the upper atmosphere: the case of halos and elves triggered by different lightning discharges
Halos and elves are Transient Luminous Events (TLEs) produced in the lower
ionosphere as a consequence of lightning-driven electromagnetic fields. These
events can influence the upper-atmospheric chemistry and produce optical
emissions. We have developed different two-dimensional self-consistent models
that couple electrodynamical equations with a chemical scheme to simulate halos
and elves produced by vertical cloud-to-ground (CG) lightning discharges,
Compact Intra-cloud Discharges (CIDs) and Energetic In-cloud Pulses (EIPs). The
optical emissions from radiative relaxation of excited states of molecular and
atomic nitrogen and oxygen have been calculated. We have upgraded previous
local models of halos and elves to calculate for the first time the
vibrationally detailed optical spectra of elves triggered by CIDs and EIPs.
According to our results, the optical spectra of elves do not depend on the
type of parent lightning discharge. Finally, we have quantified the local
chemical impact in the upper atmosphere of single halos and elves. In the case
of the halo, we follow the cascade of chemical reactions triggered by the
lightning-produced electric field during a long-time simulation of up to one
second. We obtain a production rate of NO molecules by single halos and elves
of 10 and 10 molecules/J, respectively. The results of these
local models have been used to estimate the global production of NO by halos
and elves in the upper atmopshere at Tg~N/y. This global chemical
impact of halos and elves is seven orders of magnitude below the production of
NO in the troposphere by lightning discharges
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