Globular cluster clustering and tidal features around ultra compact dwarf galaxies in the halo of NGC1399

We present a novel approach to constrain the formation channels of Ultra-Compact Dwarf Galaxies (UCDs). This inhomogeneous class of objects of remnants of tidally stripped dwarf elliptical galaxies and high mass globular clusters. We use three methods to unravel their nature: 1) we analysed their surface brightness profiles, 2) we carried out a direct search for tidal features around UCDs and 3) we compared the spatial distribution of GCs and UCDs in the halo of their host galaxy. Based on FORS2 observations, we have studied the detailed structural composition of a large sample of 97 UCDs in the halo of NGC1399, the central galaxy of the Fornax cluster, by analysing theirsurface brightness profiles. We derived the structural parameters of 13 extended UCDs modelling them with a single Sersic function and decomposing them into composite King and Sersic profiles. We find evidence for faint stellar envelopes at mu=~26 mag\arcsec^-2 surrounding the UCDs up to an extension of 90pc in radius. We also show new evidence for faint asymmetric structures and tidal tail-like features surrounding several of these UCDs, a possible tracer of their origin and assembly history within their host galaxy halos. In particular, we present evidence for the first discovery of a significant tidal tail with an extension of ~350pc around UCD-FORS2. We searched for local overdensities in the spatial distribution of globular clusters within the halo of NGC1399, to see if they are related to the positions of the UCDs. We found a local overabundance of globular clusters on a scale of <1kpc around UCDs, when we compare it to the distribution of globulars from the host galaxy. This effect is strongest for the metal-poor blue GCs. We discuss how likely it is that these clustered globulars were originally associated with the UCD.Comment: 21 pages, 14 figures, accepted for publication in A&

Height analysis of amorphous and crystalline ice structures on Cu(111) in scanning tunneling microscopy

Scanning tunneling microscopy imaging of amorphous and crystalline D2O ice on Cu(111) is discussed with respect to the apparent and the real heights of these structures above the metal surface. The apparent height increases linearly below the conduction band onset of amorphous ice and the first image state of crystalline ice, respectively. However, it largely underestimates the real height. For these voltages, histograms of the apparent height can be used to identify different layers. The dependence of the apparent height on voltage increases step-like up to the real height at the onsets of the first unoccupied electronic state. Apparent height spectroscopy is utilized to relate the apparent height to the real height of the different structures. The analysis reveals the layering during growth of porous amorphous ice between 0.1 and 1.4 BL and the dynamics of crystallization between 130 and 145 K.DF

Inequality in EU Crisis Countries: How Effective Were Automatic Stabilisers? ESRI DISCUSSION PAPER SERIES IZA DP No. 11439, March 2018

The Great Recession and the widespread adoption of fiscal austerity policies have heightened concern about inequality and how well tax-benefit systems redistribute. We examine how the distribution of income in the EU countries which were hardest hit during the recession evolved over this time. Using and extending a recently developed framework (Savage et al., 2017), the overall change in income inequality is decomposed into parts attributable to the change in market income inequality, changes in discretionary tax-benefit policy and automatic stabilisation effects. We implement this approach using the microsimulation software, EUROMOD, linked to EU-SILC survey data. Automatic stabilisation effects, particularly through benefits, are found to play an important role in reducing inequality in all the crisis countries. Their role is less important if we focus on the working age population only, due to the relative importance of old-age benefits in southern European welfare systems. Discretionary policy changes also contributed to reductions in inequality, but to a much lesser extent

Water Adsorption at the Tetrahedral Titania Surface Layer of SrTiO3_3(110)-(4×\times1)

The interaction of water with oxide surfaces is of great interest for both fundamental science and applications. We present a combined theoretical [density functional theory (DFT)] and experimental [Scanning Tunneling Microscopy (STM), photoemission spectroscopy (PES)] study of water interaction with the two-dimensional titania overlayer that terminates the SrTiO$_3$(110)-(4$\times$1) surface and consists of TiO$_4$ tetrahedra. STM, core-level and valence band PES show that H$_2$O neither adsorbs nor dissociates on the stoichiometric surface at room temperature, while it dissociates at oxygen vacancies. This is in agreement with DFT calculations, which show that the energy barriers for water dissociation on the stoichiometric and reduced surfaces are 1.7 and 0.9 eV, respectively. We propose that water weakly adsorbs on two-dimensional, tetrahedrally coordinated overlayers

То що ж їсти?

Gingivitis and periodontitis are chronic inflammatory diseases that can lead to tooth loss. One of the causes of these diseases is the Gram-negative Porphyromonas gingivalis. This periodontal pathogen is dependent on two fimbriae, FimA and Mfa1, for binding to dental biofilm, salivary proteins, and host cells. These fimbriae are composed of five proteins each, but the fimbriae assembly mechanism and ligands are unknown. Here we reveal the crystal structure of the precursor form of Mfa4, one of the accessory proteins of the Mfa1 fimbria. Mfa4 consists of two β-sandwich domains and the first part of the structure forms two well-defined β-strands that run over both domains. This N-terminal region is cleaved by gingipains, a family of proteolytic enzymes that encompass arginine- and lysine-specific proteases. Cleavage of the N-terminal region generates the mature form of the protein. Our structural data allow us to propose that the new N-terminus of the mature protein may function as a donor strand in the polymerization of P. gingivalis fimbriae

Political economy model forecast: the left will win a comfortable victory in the Danish general election

With the Danish general election only a few days away, what can forecasting models tell us about the outcome? Drawing on a model that features economic growth, Richard Nadeau, Michael S. Lewis-Beck and Karina Kosiara-Pedersen predict a comfortable win for a left coalition led by the ruling Social Democrats