Most recent highlights from EPL:
Information content: Assessing meso-scale structures in complex networks1
by M. Zanin et al.
We propose a novel measure to assess the presence of meso-scale structures in complex networks. This measure is based on the identification of regular patterns in the adjacency matrix of the network, and on the calculation of the quantity of information lost when pairs of nodes are iteratively merged. We show how this measure is able to quantify several meso-scale structures, like the presence of modularity, bipartite and core-periphery configurations, or motifs. Results corresponding to a large set of real networks are used to validate its ability to detect non-trivial topological patterns.
Intense infrared scintillation of liquid Ar-Xe mixtures2
by A. Neumeier et al.
Intense infrared (IR) light emission from liquid Ar-Xe mixtures has been observed using 12 keV electron-beam excitation. The emission peaks at a wavelength of 1.18 μm and the half-width of the emission band is 0.1 μm. Maximum intensity has been found for a 10 ppm xenon admixture in liquid argon. The conversion efficiency of electron-beam power to IR light is about 1% (10,000 photons per MeV electron energy deposited). A possible application of this intense IR emission for a new particle discrimination concept in liquid noble gas detectors is discussed. No light emission was found for perfectly purified liquid argon in the wavelength range from 0.5 to 3.5 μm on the current level of sensitivity.
Strange eigenmodes and chaotic advection in open fluid flows3
by Alessandro P. S. de Moura.
We study the dynamics of mixing of advected fields in open chaotic flows. We propose the eigenfunctions of the stroboscopic advection-diffusion (SAD) operator as the natural generalisations of the concept of strange eigenmodes for open flows, and argue that its eigenvalues determine the long-time dynamics of mixing. We characterise their dependence on diffusivity and on the properties of the chaotic advection. In particular, we find that the SAD eigenvalues are determined by the dynamical invariants of the chaotic saddle, and that the eigenmodes mirror its fractal geometry. Furthermore, we find that the dependence of the SAD eigenvalues on the diffusivity is strikingly different for hyperbolic and non-hyperbolic flows. In the latter case, we show strong evidence of an anomalous scaling of the eigenvalues with the diffusivity.
A paradox in community detection4
by Filippo Radicchi.
Recent research has shown that virtually all algorithms aimed at the identification of communities in networks are affected by the same main limitation: the impossibility to detect communities, even when these are well defined, if the average value of the difference between internal and external node degrees does not exceed a strictly positive value, in the literature known as detectability threshold. Here, we counterintuitively show that the value of this threshold is inversely proportional to the intrinsic quality of communities: the detection of well-defined modules is thus more difficult than the identification of ill-defined communities.
Continuum dynamics of elastocapillary coalescence and arrest5
by Z. Wei and L. Mahadevan.
The surface-tension–driven coalescence of wet hair, nano-pillars and supported lamellae immersed in an evaporating liquid is eventually arrested elastically. To characterize this at a continuum level, we start from a discrete microscopic model of the process and derive a mesoscopic theory that couples the inhomogeneous dynamics of drying to the capillary forcing and elastic bending of the lamellae. Numerical simulations of the resulting partial differential equation capture the primary unstable mode seen in experiments, and the dynamic coalescence of the lamellae into dimers and quadrimers. Our theory also predicts the elastic arrest of the pattern or the separation of lamellar bundles into their constituents as a function of the amount of liquid left at the end of the process.
- M. Zanin et al. 2014. Information content: Assessing meso-scale structures in complex networks. EPL, 106, 30001. DOI: 10.1209/0295-5075/105/30001 [↩]
- A. Neumeier et al. 2014. Intense infrared scintillation of liquid Ar-Xe mixtures. EPL, 106, 32001. DOI: 10.1209/0295-5075/106/32001 [↩]
- Alessandro P. S. de Moura. 2014. Strange eigenmodes and chaotic advection in open fluid flows. EPL, 106, 34002. DOI: 10.1209/0295-5075/106/34002 [↩]
- Filippo Radicchi. 2014. A paradox in community detection. EPL, 106, 38001. DOI: 10.1209/0295-5075/106/38001 [↩]
- Z. Wei and L. Mahadevan. 2014. Continuum dynamics of elastocapillary coalescence and arrest. EPL, 106, 14002. DOI: 10.1209/0295-5075/106/14002 [↩]