493 research outputs found
Toward Defining Literacy
Literacy is a topic much on the public\u27s mind these days. It is one of those subjects on which all laypersons think they are experts. When it comes time, however, to establish measures of illiteracy rates or to set policies, it becomes apparent that we know less than we thought we did. It is small comfort to know that specialists also have their differences
Anderson Localization in Euclidean Random Matrices
We study spectra and localization properties of Euclidean random matrices.
The problem is approximately mapped onto that of a matrix defined on a random
graph. We introduce a powerful method to find the density of states and the
localization threshold. We solve numerically an exact equation for the
probability distribution function of the diagonal element of the the resolvent
matrix, with a population dynamics algorithm, and we show how this can be used
to find the localization threshold. An application of the method in the context
of the Instantaneous Normal Modes of a liquid system is given.Comment: 4 page
Linear Complexity Lossy Compressor for Binary Redundant Memoryless Sources
A lossy compression algorithm for binary redundant memoryless sources is
presented. The proposed scheme is based on sparse graph codes. By introducing a
nonlinear function, redundant memoryless sequences can be compressed. We
propose a linear complexity compressor based on the extended belief
propagation, into which an inertia term is heuristically introduced, and show
that it has near-optimal performance for moderate block lengths.Comment: 4 pages, 1 figur
Regulatory networks and connected components of the neutral space
The functioning of a living cell is largely determined by the structure of
its regulatory network, comprising non-linear interactions between regulatory
genes. An important factor for the stability and evolvability of such
regulatory systems is neutrality - typically a large number of alternative
network structures give rise to the necessary dynamics. Here we study the
discretized regulatory dynamics of the yeast cell cycle [Li et al., PNAS, 2004]
and the set of networks capable of reproducing it, which we call functional.
Among these, the empirical yeast wildtype network is close to optimal with
respect to sparse wiring. Under point mutations, which establish or delete
single interactions, the neutral space of functional networks is fragmented
into 4.7 * 10^8 components. One of the smaller ones contains the wildtype
network. On average, functional networks reachable from the wildtype by
mutations are sparser, have higher noise resilience and fewer fixed point
attractors as compared with networks outside of this wildtype component.Comment: 6 pages, 5 figure
Quantum discord and related measures of quantum correlations in XY chains
We examine the quantum correlations of spin pairs in the ground state of
finite XY chains in a transverse field, by evaluating the quantum discord as
well as other related entropic measures of quantum correlations. A brief review
of the latter, based on generalized entropic forms, is also included. It is
shown that parity effects are of crucial importance for describing the behavior
of these measures below the critical field. It is also shown that these
measures reach full range in the immediate vicinity of the factorizing field,
where they become independent of separation and coupling range. Analytical and
numerical results for the quantum discord, the geometric discord and other
measures in spin chains with nearest neighbor coupling and in fully connected
spin arrays are also provided.Comment: accepted in Int. J. Mod. Phys. B, special issue "Classical Vs Quantum
correlations in composite systems" edited by L. Amico, S. Bose, V. Korepin
and V. Vedra
Study of MicroPattern Gaseous detectors with novel nanodiamond based photocathodes for single photon detection in EIC RICH
Identification of high momentum hadrons at the future EIC is crucial, gaseous
RICH detectors are therefore viable option. Compact collider setups impose to
construct RICHes with small radiator length, hence significantly limiting the
number of detected photons. More photons can be detected in the far UV region,
using a windowless RICH approach. QE of CsI degrades under strong irradiation
and air contamination. Nanodiamond based photocathodes (PCs) are being
developed as an alternative to CsI. Recent development of layers of
hydrogenated nanodiamond powders as an alternative photosensitive material and
their performance, when coupled to the THick Gaseous Electron Multipliers
(THGEM)-based detectors, are the objects of an ongoing R\&D. We report about
the initial phase of our studies.Comment: 3 pages, 5 figures, RICH2018 conference proceedin
On the origin of the Boson peak in globular proteins
We study the Boson Peak phenomenology experimentally observed in globular
proteins by means of elastic network models. These models are suitable for an
analytic treatment in the framework of Euclidean Random Matrix theory, whose
predictions can be numerically tested on real proteins structures. We find that
the emergence of the Boson Peak is strictly related to an intrinsic mechanical
instability of the protein, in close similarity to what is thought to happen in
glasses. The biological implications of this conclusion are also discussed by
focusing on a representative case study.Comment: Proceedings of the X International Workshop on Disordered Systems,
Molveno (2006
- …