On the anomalous red giant branch of the globular cluster Omega Cen

We present three different optical and near-infrared (NIR) data sets for evolved stars in the Galactic Globular Cluster Omega Cen The comparison between observations and homogeneous sets of stellar isochrones and Zero-Age Horizontal Branches provides two reasonable fits. Both of them suggest that the so-called anomalous branch has a metal-intermediate chemical composition (-1.1 < [Fe/H] < -0.8) and is located ~500 pc beyond the bulk of Omega Cen stars. These findings are mainly supported by the shape of the subgiant branch in four different color-magnitude diagrams (CMDs). The most plausible fit requires a higher reddening, E(B-V)=0.155 vs. 0.12, and suggests that the anomalous branch is coeval, within empirical and theoretical uncertainties, to the bulk of Omega Cen stellar populations. This result is supported by the identification of a sample of faint horizontal branch stars that might be connected with the anomalous branch. Circumstantial empirical evidence seems to suggest that the stars in this branch form a clump of stars located beyond the cluster.Comment: Accepted for publication on ApJ. High resolution figures can be downloaded from ftp://ftp.mporzio.astro.it/dist/monelli2

The Observation of Up-going Charged Particles Produced by High Energy Muons in Underground Detectors

An experimental study of the production of up-going charged particles in inelastic interactions of down-going underground muons is reported, using data obtained from the MACRO detector at the Gran Sasso Laboratory. In a sample of 12.2 10^6 single muons, corresponding to a detector livetime of 1.55 y, 243 events are observed having an up-going particle associated with a down-going muon. These events are analysed to determine the range and emission angle distributions of the up-going particle, corrected for detection and reconstruction efficiency. Measurements of the muon neutrino flux by underground detectors are often based on the observation of through-going and stopping muons produced in $\nu_\mu$ interactions in the rock below the detector. Up-going particles produced by an undetected down-going muon are a potential background source in these measurements. The implications of this background for neutrino studies using MACRO are discussed.Comment: 18 pages, 9 figures. Accepted by Astrop. Physic

DVLN e DKN. Modelli visuo-spaziali di rappresentazione e sviluppo dei significati nella formazione a distanza. Un approccio multidisciplinare

La ricerca sugli ambienti di apprendimento collaborativi in ambito virtuale esprime, attualmente, il crescente interesse verso modalità di approccio “orizzontali” alla relazione insegnamento-apprendimento; proposte significative di interazione collaborativa i cui vantaggi di efficacia formativa risultano evidenti non soltanto in relazione alle forme tradizionali dell’istruzione, ma anche nei confronti del design elearning il cui impianto si basi soltanto sul lavoro individuale. Uno dei punti di maggiore interesse è l’idea che la co-costruzione collaborativa degli apprendimenti on line produca un incremento delle spinte motivazionali, del coinvolgimento partecipativo, delle abilità metariflessive e delle istanze di riconoscimento e di appartenenzaall’interno della propria comunità di apprendimento o della comunità verso la quale ci si sente responsabili da un punto di vista culturale

On the anomalous red giant branch of the globular cluster omega Centauri

We present three different optical and near-infrared (NIR) data sets for evolved stars in the Galactic globular cluster omega Centauri. The comparison between observations and homogeneous sets of stellar isochrones and zero-age horizontal branches provides two reasonable fits. Both of them suggest that the so-called anomalous branch has a metal-intermediate chemical composition (-1.1 <= [Fe/H] <= -0.8) and is located similar to 500 pc beyond the bulk of omega Cen stars. These findings are mainly supported by the shape of the subgiant branch in four different color-magnitude diagrams (CMDs). The most plausible fit requires a higher reddening, E(B - V) = 0.155 versus 0.12, and suggests that the anomalous branch is coeval with the bulk of omega Cen stellar populations to within empirical and theoretical uncertainties. This result is supported by the identification of a sample of faint horizontal-branch (HB) stars that might be connected with the anomalous branch. Circumstantial empirical evidence seems to suggest that the stars in this branch form a clump of stars located beyond the cluster

Educazione, relazioni, affetti. Oltre la pandemia

Il volume raccoglie il dialogo di docenti e ricercatori dei processi educativi e formativi intorno agli aspetti emozionali dell'educazione, alle latenze e agli impliciti del lavoro formativo ed educativoThe volume collects the dialogue of professors and researchers of educational and training processes on the emotional dimensions of human education, latencies and implicits of training and educational wor