Galaxy evolution in nearby galaxy groups. III. A GALEX view of NGC 5846, the largest group in the local universe

We explore the co-evolution of galaxies in nearby groups (V < 3000 km/s) with a multi-wavelength approach. We analyze GALEX far-UV (FUV) and near-UV (NUV) imaging and SDSS u,g,r,i,z data of groups spanning a large range of dynamical phases. We characterize the photometric properties of spectroscopically-confirmed galaxy members and investigate the global properties of the groups through a dynamical analysis. Here we focus on NGC 5846, the third most massive association of Early-Type Galaxies (ETG) after the Virgo and Fornax clusters. The group, composed of 90 members, is dominated by ETGs (about 80 per cent), and among ETGs about 40\% are dwarfs. Results are compared with those obtained for three groups in the LeoII cloud, which are radically different both in member-galaxy population and dynamical properties. The FUV-NUV cumulative colour distribution and the normalized UV luminosity function (LF) significantly differ due to the different fraction of late-type galaxy population. The UV LF of NGC 5846 resembles that of the Virgo cluster, however our analysis suggests that star-formation episodes are still occurring in most of the group galaxies, including ETGs. The NUV-i colour distribution, the optical-UV colour-colour diagram, and NUV-r vs. Mr colour-magnitude relation suggest that the gas contribution cannot be neglected in the evolution of ETG-type group members. Our analysis highlights that NGC~5846 is still in an active phase of its evolution, notwithstanding the dominance of dwarf and bright ETGs and its virialized configuration.Comment: 26 pages, 13 figures, accepted for publication in MNRA

Spatially Precise DNA Bending Is an Essential Activity of the Sox2 Transcription Factor

Sox proteins, a subclass of high mobility group box proteins, govern cell fate decisions by acting both as classical transcription factors and architectural components of chromatin. We aimed to demonstrate that the DNA bending activity of Sox proteins is essential to regulate gene expression. We focused on mouse Sox2, which participates in the transactivation of the Fgf4 (fibroblast growth factor 4) gene in the inner cell mass of the blastocyst. We generated six substitutions in the high mobility group box of Sox2. One mutant showed a reduced DNA bending activity on the Fgf4 enhancer (46 degrees instead of 80 degrees), which resulted in more powerful transactivation compared with the wild type protein. We then selected two single-base mutations in the Fgf4 enhancer that make the DNA less bendable by the Sox2 protein. Again, a different DNA bend (0 degrees and 42 degrees instead of 80 degrees) resulted in a different activation of transcription, but in this case reduced bending corresponded to decreased transcription. We found that the opposite effect on transcription of similar DNA bending angles is due to a 20 degrees difference in the relative orientation of the DNA bends, proving that a correct three-dimensional geometry of enhanceosome complexes is necessary to promote transcription

Pyruvate kinase deficiency

Over the past few years the inherited disorders of erythrocyte metabolism have been the object of intensive research which has resulted in a better understanding of their molecular basis. However, curative therapy for red blood cell (RBC) enzyme defects still remains undeveloped. Among glycolyti

Role revolution: towards a new meaning of positions in basketball

Most team sports are characterized by positions to which the players in a team are assigned. The goal of this classification is to attribute specific responsibilities during a game. Moreover, the same classification drives the buying and selling of players according to team managers and coaches strategies. The existing positions - often defined a long time ago - tend to reflect traditional points of view about the game and sometimes they are no longer well-suited to the new concepts arisen with the evolution of the way of playing.   This paper focuses on basketball and aims at describing new roles of players during the game, by means of the analysis of players' performance statistics with data mining and machine learning tools. In detail, self-organizing maps and fuzzy clustering procedures are adopted in tandem to define groups of players with similar way of playing. The results show that, when considering the modern basketball players' statistics, classical positions are not able to fully represent their way of playing, and a new set of 5 roles emerges as a meaningful classification of players' characteristics