61 research outputs found
Intraoperative breast specimen assessment in breast conserving surgery: Comparison between standard mammography imaging and a remote radiological system
Expanding direction of the period doubling operator
We prove that the period doubling operator has an expanding direction at the
fixed point. We use the induced operator, a ``Perron-Frobenius type operator'',
to study the linearization of the period doubling operator at its fixed point.
We then use a sequence of linear operators with finite ranks to study this
induced operator. The proof is constructive. One can calculate the expanding
direction and the rate of expansion of the period doubling operator at the
fixed point
Low density expansion for Lyapunov exponents
In some quasi-one-dimensional weakly disordered media, impurities are large
and rare rather than small and dense. For an Anderson model with a low density
of strong impurities, a perturbation theory in the impurity density is
developed for the Lyapunov exponent and the density of states. The Lyapunov
exponent grows linearly with the density. Anomalies of the Kappus-Wegner type
appear for all rational quasi-momenta even in lowest order perturbation theory
Imaging, histology and ormonal features of five cases of male breast cancer observed in a single year: comparison with literature
Entanglement in the quantum Ising model
We study the asymptotic scaling of the entanglement of a block of spins for
the ground state of the one-dimensional quantum Ising model with transverse
field. When the field is sufficiently strong, the entanglement grows at most
logarithmically in the number of spins. The proof utilises a transformation to
a model of classical probability called the continuum random-cluster model, and
is based on a property of the latter model termed ratio weak-mixing. Our proof
applies equally to a large class of disordered interactions
Semantic distillation: a method for clustering objects by their contextual specificity
Techniques for data-mining, latent semantic analysis, contextual search of
databases, etc. have long ago been developed by computer scientists working on
information retrieval (IR). Experimental scientists, from all disciplines,
having to analyse large collections of raw experimental data (astronomical,
physical, biological, etc.) have developed powerful methods for their
statistical analysis and for clustering, categorising, and classifying objects.
Finally, physicists have developed a theory of quantum measurement, unifying
the logical, algebraic, and probabilistic aspects of queries into a single
formalism. The purpose of this paper is twofold: first to show that when
formulated at an abstract level, problems from IR, from statistical data
analysis, and from physical measurement theories are very similar and hence can
profitably be cross-fertilised, and, secondly, to propose a novel method of
fuzzy hierarchical clustering, termed \textit{semantic distillation} --
strongly inspired from the theory of quantum measurement --, we developed to
analyse raw data coming from various types of experiments on DNA arrays. We
illustrate the method by analysing DNA arrays experiments and clustering the
genes of the array according to their specificity.Comment: Accepted for publication in Studies in Computational Intelligence,
Springer-Verla
Role of axillary ultrasound in the preopertaive diagnosi of lymphonode metastases in patients affected by brest carcinoma
Non-Mean-Field Behavior of Realistic Spin Glasses
We provide rigorous proofs which show that the main features of the Parisi
solution of the Sherrington-Kirkpatrick spin glass are not valid for more
realistic spin glass models in any dimension and at any temperature.Comment: LaTeX file, 8 page
B3 core biopsies should be assumed as positive findings for accuracy purposes Le biopsie percutanee B3 dovrebbero essere assunte come reperti positivi nella valutazione di accuratezza
Instability of the anomalies in the one-dimensional Anderson model at weak disorder
We study the asymptotic behavior of the invariant measure, the Lyapunov exponent, and the density of states in the weak disorder limit in the case where the single-site potential distribution μ is not centered and for the special energies E =cos( πp/q ). We also prove that in general the above quantities can be continuously extended to zero disorder as continuous functions in the disorder parameter for all energies E ∈(−1, 1).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45159/1/10955_2005_Article_BF01029199.pd
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