26,733 research outputs found
“Though this be madness, yet there is method in’t.” A counterfactual analysis of Richard Wagner’s Tannhäuser
Much like Wagner himself, the eponymous hero of Tannhäuser treads a path of stark contrasts and
rapid swings. From Wartburg to the Venusberg and to the Vatican, the gifted bard transforms from
self-centered artist to seduced disciple, disillusioned devotee, hopeful lover, self-loathing pilgrim and
finally redeemed martyr. He tries everything and everything is trying. These contrasts reach a peak in
the opera‟s central episode, the song contest at Wartburg. Tannhäuser has just been welcomed at the
court, received Elisabeth‟s favor and affection, and is ready to compete for the contest‟s prize, one as
lofty as possibly the princess‟ hand. Instead of securing his reintegration to Wartburg with a brilliant
performance, however, he spoils the event with insolent remarks and the exhibitionist disclosure of
his Venusberg experience. His behavior offends his peers, scandalizes the court, breaks Elisabeth‟s
heart, and brings him to the edge of death. Why would Tannhäuser sacrifice everything for nothing
Background Configurations, Confinement and Deconfinement on a Lattice with BPS Monopole Boundary Conditions
Finite temperature SU(2) lattice gauge theory is investigated in a 3D cubic
box with fixed boundary conditions provided by a discretized, static BPS
monopole solution with varying core scale . Using heating and cooling
techniques we establish that for discrete -values stable classical
solutions either of self-dual or of pure magnetic type exist inside the box.
Having switched on quantum fluctuations we compute the Polyakov line and other
local operators. For different and at varying temperatures near the
deconfinement transition we study the influence of the boundary condition on
the vacuum inside the box. In contrast to the pure magnetic background field
case, for the self-dual one we observe confinement even for temperatures quite
far above the critical one.Comment: to appear in EPJ
Expression of PIK3CA mutant E545K in the mammary gland induces heterogeneous tumors but is less potent than mutant H1047R.
The phosphoinositide 3-kinase (PI3K) signaling cascade is a key mediator of cellular growth, survival and metabolism and is frequently subverted in human cancer. The gene encoding for the alpha catalytic subunit of PI3K (PIK3CA) is mutated and/or amplified in ∼30% of breast cancers. Mutations in either the kinase domain (H1047R) or the helical domain (E545K) are most common and result in a constitutively active enzyme with oncogenic capacity. PIK3CA(H1047R) was previously demonstrated to induce tumors in transgenic mouse models; however, it was not known whether overexpression of PIK3CA(E545K) is sufficient to induce mammary tumors and whether tumor initiation by these two types of mutants differs. Here, we demonstrate that expression of PIK3CA(E545K) in the mouse mammary gland induces heterogenous mammary carcinomas but with a longer latency than PIK3CA(H1047R)-expressing mice. Our results suggest that the helical domain mutant PIK3CA(E545K) is a less potent inducer of mammary tumors due to less efficient activation of downstream Akt signaling
Environment assisted electron capture
Electron capture by {\it isolated} atoms and ions proceeds by
photorecombination. In this process a species captures a free electron by
emitting a photon which carries away the excess energy. It is shown here that
in the presence of an {\it environment} a competing non-radiative electron
capture process can take place due to long range electron correlation. In this
interatomic (intermolecular) process the excess energy is transferred to
neighboring species. The asymptotic expression for the cross section of this
process is derived. We demonstrate by explicit examples that under realizable
conditions the cross section of this interatomic process can clearly dominate
that of photorecombination
Identification of an average temperature and a dynamical pressure in a multitemperature mixture of fluids
We present a classical approach of a mixture of compressible fluids when each
constituent has its own temperature. The introduction of an average temperature
together with the entropy principle dictates the classical Fick law for
diffusion and also novel constitutive equations associated with the difference
of temperatures between the components. The constitutive equations fit with
results recently obtained through Maxwellian iteration procedure in extended
thermodynamics theory of multitemperature mixtures. The differences of
temperatures between the constituents imply the existence of a new dynamical
pressure even if the fluids have a zero bulk viscosity. The nonequilibrium
dynamical pressure can be measured and may be convenient in several physical
situations as for example in cosmological circumstances where - as many authors
assert - a dynamical pressure played a major role in the evolution of the early
universe.Comment: 16 page
Single hole doped strongly correlated ladder with a static impurity
We consider a strongly correlated ladder with diagonal hopping and exchange
interactions described by type hamiltonian. We study the dynamics of a
single hole in this model in the presence of a static non-magnetic (or
magnetic) impurity. In the case of a non-magnetic (NM) impurity we solve the
problem analytically both in the triplet (S=1) and singlet (S=0) sectors. In
the triplet sector the hole doesn't form any bound state with the impurity.
However, in the singlet sector the hole forms bound states of different
symmetries with increasing values. Binding energies of those
impurity-hole bound states are compared with the binding energy of a pair of
holes in absence of any impurity. In the case of magnetic impurity the
analytical eigenvalue equations are solved for a large (50 X 2) lattice. In
this case also, with increasing values, impurity-hole bound states of
different symmetries are obtained. Binding of the hole with the impurity is
favoured for the case of a ferromagnetic (FM) impurity than in the case of
antiferromagnetic (AFM) impurity. However binding energy is found to be maximum
for the NM impurity. Comparison of binding energies and various impurity-hole
correlation functions indicates a pair breaking mechanism by NM impurity.Comment: 15 Pages, 6 figure
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