ON THE RELATIONSHIP BETWEEN A BANKS EQUITY HOLDINGS AND BANK PERFORMANCE

The purpose of this paper is to provide empirical evidence on the effects of a banks equity holdings in firms on the banks performance. The analysis is based on accounting measures of Spanish banks, from 1992 to 2000. The findings support a positive relation between total equity stakes and bank performance. Furthermore, we find different implications depending on the type of bank holdings considered. The results indicate that the effects on bank performance are the best when holdings are in group and nonfinancial firms.

Robust beamforming for interference rejection in mobile communications

The problem of robust beamformer design in the presence of moving sources is considered. A new technique based on a generalization of the constrained minimum variance beamformer is proposed. The method explicitly takes into account changes in the scenario due to the movement of the desired and interfering sources, requiring only estimation of the desired DOA. Computer simulations show that the resulting performance constitutes a compromise between interference and noise rejection, computational complexity, and sensitivity to source movement.Peer ReviewedPostprint (published version

Spectroscopic characterization of X-ray emitting young stars associated with the Sh 2-296 nebula

We studied a sample of stars associated with the Sh 2-296 nebula, part of the reflection nebulae complex in the region of Canis Major (CMa R1). Our sample corresponds to optical counterparts of X-ray sources detected from observations with the XMM-Newton satellite, which revealed dozens of possible low-mass young stars not yet known in this region. A sample of 58 young star candidates were selected based on optical spectral features, mainly H{\alpha} and lithium lines, observed with multi-objects spectroscopy performed by the Gemini South telescope. Among the candidates, we find 41 confirmed T Tauri and 15 very likely young stars. Based on the H{\alpha} emission, the T Tauri stars were distinguished between classical (17%) and weak-lined (83%), but no significant difference was found in the age and mass distribution of these two classes. The characterization of the sample was complemented by near- and mid-infrared data, providing an estimate of ages and masses from the comparison with pre-main-sequence evolutionary models. While half of the young stars have an age of 1-2 Myrs or less, only a small fraction (~25%) shows evidence of IR excess revealing the presence of circumstellar discs. This low fraction is quite rare compared to most young star-forming regions, suggesting that some external factor has accelerated the disc dissipation

Star formation history of Canis Major OB1 - II. A bimodal X-ray population revealed by XMM-Newton

The Canis Major OB1 Association has an intriguing scenario of star formation, especially in the Canis Major R1 (CMa R1) region traditionally assigned to a reflection nebula, but in reality an ionized region. This work is focused on the young stellar population associated to CMa R1, for which our previous results from ROSAT, optical and near-infrared data had revealed two stellar groups with different ages, suggesting a possible mixing of populations originated from distinct star-formation episodes. The X-ray data allow the detected sources to be characterized according to hardness ratios, light curves and spectra. Estimates of mass and age were obtained from the 2MASS catalogue, and used to define a complete subsample of stellar counterparts, for statistical purposes. A catalogue of 387 XMM-Newton sources is provided, 78% being confirmed as members or probable members of the CMa R1 association. Flares were observed for 13 sources, and the spectra of 21 bright sources could be fitted by a thermal plasma model. Mean values of fits parameters were used to estimate X-ray luminosities. We found a minimum value of log(L$_X$[erg/s]) = 29.43, indicating that our sample of low-mass stars (M$_\star$ $\leq$ 0.5 M$_\odot$), being faint X-ray emitters, is incomplete. Among the 250 objects selected as our complete subsample (defining our best sample), 171 are found to the East of the cloud, near Z CMa and dense molecular gas, 50% of them being young ( 10 Myr). The opposite happens to the West, near GU CMa, in areas lacking molecular gas: among 79 objects, 30% are young and 50% are older. These findings confirm that a first episode of distributed star formation occurred in the whole studied region ~10 Myr ago and dispersed the molecular gas, while a second, localized episode (< 5 Myr) took place in the regions where molecular gas is still present.Comment: 38 pages, 21 figures, accepted for A&