Photometric and kinematical study of nearby groups of galaxies around IC 65 and NGC 6962

We discuss the structure, galaxy content and kinematics of a sparse, probably collapsing group around IC 65 and an evolved rich group around NGC 6962Comment: Poster contribution on 2 pages with 2 figures to be published in ESO Astrophysics Symposia: "Groups of Galaxies in the Nearby Universe", eds. I. Saviane, V. Ivanov, J. Borissov

Dynamics and Shape of Brightest Cluster Galaxies

We identified Brightest Cluster Members (BCM) on DSS images of 1083 Abell clusters, derived their individual and host cluster redshifts from literature and determined the BCM ellipticity. Half the BCMs move at a speed higher than 37 % of the cluster velocity dispersion sigma_{cl}, suggesting that most BCMs are part of substructures falling into the main cluster. Both, the BCM's velocity offset in units of sigma_{cl}, and BCM ellipticity, weakly decrease with cluster richness.Comment: 2 pages, 2 figures, Proc. ESO Workshop "Groups of galaxies in the nearby Universe", Santiago, Chile, 5-9 Dec. 2005, ESO Astrophysics Symposia, eds. I. Saviane, V. Ivanov & J. Borissova, Springer-Verla

Ignore the vetoes, and forget about Coalitions of the Willing: How the U.S. can achieve higher levels of foreign public support for its military operations

In the early 2000s, the US gained a great deal of foreign criticism over its military operations in Iraq, and later, Afghanistan. But what determines whether the foreign public will support such interventions? In new research which uses survey research based in Japan, Atsushi Tago finds that the use of force in the Middle East by the US is most likely to be supported by foreigners when it also has the approval of the United Nations Security Council, and that much of that support continues even if the UN resolution is vetoed by Russia and China. Significantly, they also find that when the US forms a friendly ‘Coalition of the Willing’, this does little to increase foreign support for military actions

Obama’s visit to Hiroshima is viewed as “a sort of” apology by the people of Japan.

This week President Obama will visit the Japanese city of Hiroshima, more than 70 years after the city was destroyed by a US nuclear attack at the end of World War II. While the White House has stated that the President will not apologize for the atomic bombing during his visit – and has also made clear that his visit should not be seen as an apology – it is hard not to link the visit to the idea of an apology. Atsushi Tago and Kazunori Inamasu conducted a Japan-wide survey and a survey of Hiroshima residents. They found evidence that while neither the people of Hiroshima nor the Japanese public more generally are looking for an apology from Obama, even without a formal statement of apology, his visit is still seen to be “a sort of apology”

Economic game theory to model the attenuation of virulence of an obligate intracellular bacterium

Diseases induced by obligate intracellular pathogens have a large burden on global human and animal health. Understanding the factors involved in the virulence and fitness of these pathogens contributes to the development of control strategies against these diseases. Based on biological observations, a theoretical model using game theory is proposed to explain how obligate intracellular bacteria interact with their host. The equilibrium in such a game shows that the virulence and fitness of the bacterium is host-triggered and by changing the host's defense system to which the bacterium is confronted, an evolutionary process leads to an attenuated strain. Although, the attenuation procedure has already been conducted in practice in order to develop an attenuated vaccine (e.g., with Ehrlichia ruminantium), there was a lack of understanding of the theoretical basis behind this process. Our work provides a model to better comprehend the existence of different phenotypes and some underlying evolutionary mechanisms for the virulence of obligate intracellular bacteria. (Résumé d'auteur

Alignment of galaxies relative to their local environment in SDSS-DR8

We study the alignment of galaxies relative to their local environment in SDSS-DR8 and, using these data, we discuss evolution scenarios for different types of galaxies. We defined a vector field of the direction of anisotropy of the local environment of galaxies. We summed the unit direction vectors of all close neighbours of a given galaxy in a particular way to estimate this field. We found the alignment angles between the spin axes of disc galaxies, or the minor axes of elliptical galaxies, and the direction of anisotropy. The distributions of cosines of these angles are compared to the random distributions to analyse the alignment of galaxies. Sab galaxies show perpendicular alignment relative to the direction of anisotropy in a sparse environment, for single galaxies and galaxies of low luminosity. Most of the parallel alignment of Scd galaxies comes from dense regions, from 2...3 member groups and from galaxies with low luminosity. The perpendicular alignment of S0 galaxies does not depend strongly on environmental density nor luminosity; it is detected for single and 2...3 member group galaxies, and for main galaxies of 4...10 member groups. The perpendicular alignment of elliptical galaxies is clearly detected for single galaxies and for members of < 11 member groups; the alignment increases with environmental density and luminosity. We confirm the existence of fossil tidally induced alignment of Sab galaxies at low z. The alignment of Scd galaxies can be explained via the infall of matter to filaments. S0 galaxies may have encountered relatively massive mergers along the direction of anisotropy. Major mergers along this direction can explain the alignment of elliptical galaxies. Less massive, but repeated mergers are possibly responsible for the formation of elliptical galaxies in sparser areas and for less luminous elliptical galaxies.Comment: 15 pages, 15 figures, accepted for publication in A&