Among patients with a Wolff–Parkinson–White (WPW) syndrome, approximately half will experience arrhythmia during their lifetime. Radiofrequency catheter ablation of the accessory atrioventricular pathway is the treatment of choice for this condition and is associated with a high success rate. Electrophysiology study is indeed the key procedure for identifying the target of radiofrequency ablati...

We have used deep high-resolution Hubble Space Telescope ACS observations to image the cluster NGC 1978 in the Large Magellanic Cloud. This high-quality photometric data set allowed us to confirm the high ellipticity (ǫ ∼0.30±0.02) of this stellar system. The derived Color Magnitude Diagram allowed a detailed study of the main evolutionary sequences: in particular we have detected the so called...

Quantification of the Galaxy’s star formation history involves both the duration and the rate of formation, with these parameters being known with different precision for different populations. The early rate of star formation is knowable from modelling chemical element data, the recent rate directly from isochrone analyses of colour-magnitude data. The field halo and globular clusters are almo...

Aims. We investigate the nature of the classical low-velocity structures in the local velocity field, i.e. the Pleiades, Hyades and Sirius moving groups. After using a wavelet transform to locate them in velocity space, we study their relation with the open clusters kinematically associated with them. Methods. By directly comparing the location of moving group stars in parallax space to the iso...

We study the problem of computing isochrones in static and dynamic road networks, where the objective is to identify the boundary of the region in range from a given source within a certain amount of time. While there is a wide range of practical applications for this problem (e. g., urban planning, geomarketing, visualizing the cruising range of a vehicle), there has been little research on fa...

We have applied a new method to analyze the horizontal branch (HB) morphology in relation to the distribution of stars near the red giant branch (RGB) tip for the globular clusters M22, M5, M68, M107, M72, M92, M3 and 47 Tuc. This new method permits determination of the cluster ages to greater accuracy than conventional isochrone fitting. Using the method in conjunction with our new high-qualit...

We have used deep HST WFPC2 observations of two fields in NGC 2420 to produce a cluster CMD down to V ≈ 27. After imposing morphological selection criteria we find eight candidate white dwarfs in NGC 2420. Our completeness estimates indicate that we have found the terminus of the WD cooling sequence. We argue that the cluster distance modulus is likely to be close to 12.10 with E(B−V) = 0.04. W...

We present a UBV CCD photometric study of four open clusters, NGC 7245, King 9, IC 166 and King 13, located between l = 90◦ and 135◦. All are embedded in a rich Galactic field. NGC 7245 and King 9 are close together in the sky and have similar reddenings. The distances and ages are: NGC 7245, 3.8 ± 0.35 kpc and 400 Myr; King 9 (the most distant cluster in this quadrant), 7.9 ± 1.1 kpc and 3.0 G...