Model of mobile agents for sexual interactions networks

We present a novel model to simulate real social networks of complex interactions, based in a granular system of colliding particles (agents). The network is build by keeping track of the collisions and evolves in time with correlations which emerge due to the mobility of the agents. Therefore, statistical features are a consequence only of local collisions among its individual agents. Agent dynamics is realized by an event-driven algorithm of collisions where energy is gained as opposed to granular systems which have dissipation. The model reproduces empirical data from networks of sexual interactions, not previously obtained with other approaches.Comment: 6 pages, 8 figure

Combined hamartoma of the retina and retinal pigment epithelium associated with optic coloboma

The authors relate an uncommon case of combined hamartoma of the retina and retinal pigment epithelium associated with optic coloboma

Deposition of general ellipsoidal particles

We present a systematic overview of granular deposits composed of ellipsoidal particles with different particle shapes and size polydispersities. We study the density and anisotropy of such deposits as functions of size polydispersity and two shape parameters that fully describe the shape of a general ellipsoid. Our results show that, while shape influences significantly the macroscopic properties of the deposits, polydispersity plays apparently a secondary role. The density attains a maximum for a particular family of non-symmetrical ellipsoids, larger than the density observed for prolate or oblate ellipsoids. As for anisotropy measures, the contact forces show are increasingly preferred along the vertical direction as the shape of the particles deviates for a sphere. The deposits are constructed by means of an efficient molecular dynamics method, where the contact forces are efficiently and accurately computed. The main results are discussed in the light of applications for porous media models and sedimentation processes.Comment: 7 pages, 8 figure

Scattering by nonspherical systems

Scattering by nonspherical particles with size of order of wavelength - scattering by axisymmetric penetrable particles using approximate matching of boundary condition

Tangled Ties: Al-Shabaab and Political Volatility in Kenya

In recent years, a spate of attacks has destabilised a swathe of Kenya’s peripheral counties as well as bringing terror to its capital, Nairobi. As violent insecurity spreads, it has fomented fear and stoked ethnic and regional divisions, precipitating security crackdowns and roiling the country’s infamously tumultuous politics. These developments belie sweeping constitutional reforms that have taken place to address and prevent violence in Kenya. Since Kenya stepped up its military involvement in Somalia in 2011, ostensibly to buffer the country from violence wrought by Al-Shabaab – the Somalia-based jihadi organisation – attacks have multiplied, ranging from the September 2013 siege of Nairobi’s Westgate shopping centre, to village massacres, to the targeted killings of police and religious figures. Yet Kenya’s government, while widening its military engagement in Somalia, was at first slow to recognise and respond to the hand of Al-Shabaab in the country’s widening violent insecurity since the start of its Somalia military operations. This study adds to existing analyses of Kenya’s shifting political and security dynamics by examining the role of external influences on its system of violence.UK Department for International Developmen

Fe I Oscillator Strengths for the Gaia-ESO Survey

The Gaia-ESO Public Spectroscopic Survey (GES) is conducting a large-scale study of multi-element chemical abundances of some 100 000 stars in the Milky Way with the ultimate aim of quantifying the formation history and evolution of young, mature and ancient Galactic populations. However, in preparing for the analysis of GES spectra, it has been noted that atomic oscillator strengths of important Fe I lines required to correctly model stellar line intensities are missing from the atomic database. Here, we present new experimental oscillator strengths derived from branching fractions and level lifetimes, for 142 transitions of Fe I between 3526 {\AA} and 10864 {\AA}, of which at least 38 are urgently needed by GES. We also assess the impact of these new data on solar spectral synthesis and demonstrate that for 36 lines that appear unblended in the Sun, Fe abundance measurements yield a small line-by-line scatter (0.08 dex) with a mean abundance of 7.44 dex in good agreement with recent publications.Comment: Accepted for publication in Mon. Not. R. Astron. So