1,043 research outputs found
Economic growth and currency crisis: A real exchange rate entropic approach
We propose a country classification of economic growth currency crisis consequences based on the entropic analysis of the real exchange rate. We show that this ranking is highly correlated with the annual minimum rate of growth, a proxy used to quantify real currency crisis effects.currency crises; entropy; growth effects of currency crises
Thermodynamics of DNA packaging inside a viral capsid: the role of DNA intrinsic thickness
We characterize the equilibrium thermodynamics of a thick polymer confined in
a spherical region of space. This is used to gain insight into the DNA
packaging process. The experimental reference system for the present study is
the recent characterization of the loading process of the genome inside the
29 bacteriophage capsid. Our emphasis is on the modelling of
double-stranded DNA as a flexible thick polymer (tube) instead of a
beads-and-springs chain. By using finite-size scaling to extrapolate our
results to genome lengths appropriate for 29, we find that the
thickness-induced force may account for up to half the one measured
experimentally at high packing densities. An analogous agreement is found for
the total work that has to be spent in the packaging process. Remarkably, such
agreement can be obtained in the absence of any tunable parameters and is a
mere consequence of the DNA thickness. Furthermore, we provide a quantitative
estimate of how the persistence length of a polymer depends on its thickness.
The expression accounts for the significant difference in the persistence
lengths of single- and double-stranded DNA (again with the sole input of their
respective sections and natural nucleotide/base-pair spacing).Comment: 9 pages, 6 eps figure
A new measure based on degree distribution that links information theory and network graph analysis
BACKGROUND: Detailed connection maps of human and nonhuman brains are being generated with new technologies, and graph metrics have been instrumental in understanding the general organizational features of these structures. Neural networks appear to have small world properties: they have clustered regions, while maintaining integrative features such as short average pathlengths. RESULTS: We captured the structural characteristics of clustered networks with short average pathlengths through our own variable, System Difference (SD), which is computationally simple and calculable for larger graph systems. SD is a Jaccardian measure generated by averaging all of the differences in the connection patterns between any two nodes of a system. We calculated SD over large random samples of matrices and found that high SD matrices have a low average pathlength and a larger number of clustered structures. SD is a measure of degree distribution with high SD matrices maximizing entropic properties. Phi (Φ), an information theory metric that assesses a system’s capacity to integrate information, correlated well with SD - with SD explaining over 90% of the variance in systems above 11 nodes (tested for 4 to 13 nodes). However, newer versions of Φ do not correlate well with the SD metric. CONCLUSIONS: The new network measure, SD, provides a link between high entropic structures and degree distributions as related to small world properties
Power-law spin correlations in pyrochlore antiferromagnets
The ground state ensemble of the highly frustrated pyrochlore-lattice
antiferromagnet can be mapped to a coarse-grained ``polarization'' field
satisfying a zero-divergence condition From this it follows that the
correlations of this field, as well as the actual spin correlations, decay with
separation like a dipole-dipole interaction (). Furthermore, a lattice
version of the derivation gives an approximate formula for spin correlations,
with several features that agree well with simulations and neutron-diffraction
measurements of diffuse scattering, in particular the pinch-point
(pseudo-dipolar) singularities at reciprocal lattice vectors. This system is
compared to others in which constraints also imply diffraction singularities,
and other possible applications of the coarse-grained polarization are
discussed.Comment: 13 pp, revtex, two figure
A quantum information theoretic analysis of three flavor neutrino oscillations
Correlations exhibited by neutrino oscillations are studied via quantum
information theoretic quantities. We show that the strongest type of
entanglement, genuine multipartite entanglement, is persistent in the flavour
changing states. We prove the existence of Bell-type nonlocal features, in both
its absolute and genuine avatars. Finally, we show that a measure of
nonclassicality, dissension, which is a generalization of quantum discord to
the tripartite case, is nonzero for almost the entire range of time in the
evolution of an initial electron-neutrino. Via these quantum information
theoretic quantities capturing different aspects of quantum correlations, we
elucidate the differences between the flavour types, shedding light on the
quantum-information theoretic aspects of the weak force.Comment: 9 pages, 6 figure
Protein folding in high-dimensional spaces:hypergutters and the role of non-native interactions
We explore the consequences of very high dimensionality in the dynamical
landscape of protein folding. Consideration of both typical range of
stabilising interactions, and folding rates themselves, leads to a model of the
energy hypersurface that is characterised by the structure of diffusive
"hypergutters" as well as the familiar "funnels". Several general predictions
result: (1) intermediate subspaces of configurations will always be visited;
(2) specific but non-native interactions are important in stabilising these
low-dimensional diffusive searches on the folding pathway; (3) sequential
barriers will commonly be found, even in "two-state"proteins; (4) very early
times will show charactreristic departures from single-exponential kinetics;
(5) contributions of non-native interactions to phi-values are calculable, and
may be significant. The example of a three-helix bundle is treated in more
detail as an illustration. The model also shows that high-dimensional
structures provide conceptual relations between the "folding funnel",
"diffusion-collision", "nucleation-condensation" and "topomer search" models of
protein folding. It suggests that kinetic strategies for fast folding may be
encoded rather generally in non-native, rather than native interactions. The
predictions are related to very recent findings in experiment and simulation.Comment: Submitted to Biophys.
Complexity of multi-dimensional spontaneous EEG decreases during propofol induced general anaesthesia
Emerging neural theories of consciousness suggest a correlation between a specific type of neural dynamical complexity and the level of consciousness: When awake and aware, causal interactions between brain regions are both integrated (all regions are to a certain extent connected) and differentiated (there is inhomogeneity and variety in the interactions). In support of this, recent work by Casali et al (2013) has shown that Lempel-Ziv complexity correlates strongly with conscious level, when computed on the EEG response to transcranial magnetic stimulation. Here we investigated complexity of spontaneous high-density EEG data during propofol-induced general anaesthesia. We consider three distinct measures: (i) Lempel-Ziv complexity, which is derived from how compressible the data are; (ii) amplitude coalition entropy, which measures the variability in the constitution of the set of active channels; and (iii) the novel synchrony coalition entropy (SCE), which measures the variability in the constitution of the set of synchronous channels. After some simulations on Kuramoto oscillator models which demonstrate that these measures capture distinct ‘flavours’ of complexity, we show that there is a robustly measurable decrease in the complexity of spontaneous EEG during general anaesthesia
- …