Mergers and Acquisitions in the Colombian Financial Sector (Impact on Efficiency 1990-2005)

Colombia has witnessed a renewed interest in merging and acquiring financial institutions during 2003-2005. These have been “complementary mergers” that seek to exploit economies scale and scope. This process contrasts favorably with those mergers & acquisitions that occurred during the mid-1990s, which involved mainly “twin institutions” that lacked potential for gaining multiproduct efficiency. This document analyzes the need to remove some of the regulatory constraints that obstruct further exploitation of such economies of scale-scope and quantifies the “cost efficiencies” shown by the Colombian banking sector (1994-2005). At the aggregate level, we found (absolute) banking efficiency to be around 63%, a similar value to those found in related studies post-crisis. This implies that banks operating in Colombia have been able to recover their efficiency levels during postcrisis 2003-2005, except for mortgage institutions. We highlight regulatory barriers that could be removed to help the banking system move closer to the optimal production frontier.Financial Institutions, Mergers and Acquisitions

The Molecular Gas in the Circumnuclear Region of Seyfert Galaxies

Sub-arcsecond IRAM Plateau de Bure mm-interferometric observations of the 12CO (2-1) line emission in the Seyfert~1 NGC 3227 and the Seyfert~2 NGC 1068 have revealed complex kinematic systems in the inner 100 pc to 300 pc that are not consistent with pure circular motion in the host galaxies. Modeling of these kinematic systems with elliptical orbits in the plane of the host galaxy (representing gas motion in a bar potential) is a possible solution but does not reproduce all features observed. A better description of the complex kinematics is achieved by circular orbits which are tilted out of the plane of the host galaxy. This could indicate that the thin circumnuclear gas disk is warped. In the case of NGC 1068 the warp model suggests that at a radius of about 70 pc, the gas disk is oriented edge-on providing material for the obscuration of the AGN nucleus. The position-velocity diagrams show rising rotation curves at r 2 x 10^7 M_solar for NGC 3227 and > 10^8 M_solar for NGC 1068 within the central 25 pc.Comment: 14 pages, Ap.J. letter, accepte

Variability of Fe II Emission Features in the Seyfert 1 Galaxy NGC 5548

We study the low-contrast Fe II emission blends in the ultraviolet (1250--2200A) and optical (4000--6000A) spectra of the Seyfert 1 galaxy NGC 5548 and show that these features vary in flux and that these variations are correlated with those of the optical continuum. The amplitude of variability of the optical Fe II emission is 50% - 75% that of Hbeta and the ultraviolet Fe II emission varies with an even larger amplitude than Hbeta. However, accurate measurement of the flux in these blends proves to be very difficult even using excellent Fe II templates to fit the spectra. We are able to constrain only weakly the optical Fe II emission-line response timescale to a value less than several weeks; this upper limit exceeds all the reliably measured emission-line lags in this source so it is not particularly meaningful. Nevertheless, the fact that the optical Fe II and continuum flux variations are correlated indicates that line fluorescence in a photoionized plasma, rather than collisional excitation, is responsible for the Fe II emission. The iron emission templates are available upon request.Comment: 34 pages including 12 figures and 2 tables. Accepted for publication by ApJ (tentatively in vol. 626 June 10, 2005

The host galaxy of GRB010222: The strongest damped Lyman-alpha system known

Analysis of the absorption lines in the afterglow spectrum of the gamma-ray burst GRB010222 indicates that its host galaxy (at a redshift of z=1.476) is the strongest damped Lyman-alpha (DLA) system known, having a very low metallicity and modest dust content. This conclusion is based on the detection of the red wing of Lyman-alpha plus a comparison of the equivalent widths of ultraviolet Mg I, Mg II, and Fe II lines with those in other DLAs. The column density of H I, deduced from a fit to the wing of Lyman-alpha, is (5 +/- 2) 10^22 cm^-2. The ratio of the column densities of Zn and Cr lines suggests that the dust content in our line of sight through the galaxy is low. This could be due to either dust destruction by the ultraviolet emission of the afterglow or to an initial dust composition different to that of the diffuse interstellar material, or a combination of both.Comment: Submitted to MNRAS 12 page

The First VLT FORS1 spectra of Lyman-break candidates in the HDF-S and AXAF Deep Field

We report on low-resolution multi-object spectroscopy of 30 faint targets (R \~ 24-25) in the HDF-S and AXAF deep field obtained with the VLT Focal Reducer/low dispersion Spectrograph (FORS1). Eight high-redshift galaxies with 2.75< z < 4 have been identified. The spectroscopic redshifts are in good agreement with the photometric ones with a dispersion $\sigma_z = 0.07$ at z<2 and $\sigma_z = 0.16$ at z>2. The inferred star formation rates of the individual objects are moderate, ranging from a few to a few tens solar masses per year. Five out of the eight high-z objects do not show prominent emission lines. One object has a spectrum typical of an AGN. In the AXAF field two relatively close pairs of galaxies have been identified, with separations of 8.7 and 3.1 proper Mpc and mean redshifts of 3.11 and 3.93, respectively.Comment: 5 pages Latex, with 2 PostScript figures. Astronomy and Astrophysics, in pres

Analyses of H2O2 production in time during wound healing

Reactive Oxygen Species (ROS) have been traditionally con- sidered as toxic species due to their capacity to damage macromolecules. However, their deleterious effect is lim- ited to high concentrations. At lower levels, further studies have shown that at least hydrogen peroxide (H2O2) acts as a second messenger and results crucial for basic biological functions. Wound healing is one of those: in several animal models, this molecule is emitted in cellular wound margins, leading to neutrophil chemoattraction, while inducing epithe- lial cell migration during skin regeneration. Nevertheless, there are no references to this phenomenon in human ex- perimental set-ups. In this study, human keratinocyte cells (HaCaT), previously modified to express a H2O2-specific ra- tiometric fluorescent sensor (HyPer7) were monitored using live imaging after generating a mechanical-like injury. The time evolution ratio of the probe and the gap area were mea- sured for both cells near the margin and for topologically secondary cells, establishing a relationship between cytosolic H2O2 fluxes and the process of refilling a wound. In addition, comparison of movement rates between HyPer7-expressing and non-expressing HaCaT cells demonstrated a profound dependency of H2O2 availability for the process to occur.This project is the result of previous work carried out by exceptional scientists in the redox field and has been developed in the UC3M facility core CleanRooms for Bioengineering. Financial support was provided by the Madrid Government (Comunidad de Madrid) under the Multiannual Agreement with UC3M in the line of ”Research Funds for Beatriz Galindo Fellow- ships” (REDOXSKIN-CM-UC3M), and in the context of the V PRICIT (Regional Programme of Research and Technological Innovation”, and from “Proyectos de I + D + I” (PID2020-114230 GA-I00) funded by MCIN/AEI/10.13039/501100011033/

An absorption event in the X-ray lightcurve of NGC 3227

We have monitored the Seyfert galaxy NGC 3227 with the Rossi X-ray Timing Explorer (RXTE) since January 1999. During late 2000 and early 2001 we observed an unusual hardening of the 2-10 keV X-ray spectrum which lasted several months. The spectral hardening was not accompanied by any correlated variation in flux above 8 keV. We therefore interpret the spectral change as transient absorption by a gas cloud of column density 2.6 10^23 cm^-2 crossing the line of sight to the X-ray source. A spectrum obtained by XMM-Newton during an early phase of the hard-spectrum event confirms the obscuration model and shows that the absorbing cloud is only weakly ionised. The XMM-Newton spectrum also shows that ~10% of the X-ray flux is not obscured, but this unabsorbed component is not significantly variable and may be scattered radiation from a large-scale scattering medium. Applying the spectral constraints on cloud ionisation parameter and assuming that the cloud follows a Keplerian orbit, we constrain the location of the cloud to be R~10-100 light-days from the central X-ray source, and its density to be n_H~10^8cm^-3, implying that we have witnessed the eclipse of the X-ray source by a broad line region cloud.Comment: 5 pages, 6 figures, accepted for publication in MNRAS letter

Luminosity Evolution of Early-type Galaxies to z=0.83: Constraints on Formation Epoch and Omega

We present deep spectroscopy with the Keck telescope of eight galaxies in the luminous X-ray cluster MS1054-03 at z=0.83. The data are combined with imaging observations from the Hubble Space Telescope (HST). The spectroscopic data are used to measure the internal kinematics of the galaxies, and the HST data to measure their structural parameters. Six galaxies have early-type spectra, and two have "E+A" spectra. The galaxies with early-type spectra define a tight Fundamental Plane (FP) relation. The evolution of the mass-to-light ratio is derived from the FP. The M/L ratio evolves as \Delta log M/L_B \propto -0.40 z (Omega_m=0.3, Omega_Lambda=0). The observed evolution of the M/L ratio provides a combined constraint on the formation redshift of the stars, the IMF, and cosmological parameters. For a Salpeter IMF (x=2.35) we find that z_form>2.8 and Omega_m<0.86 with 95% confidence. The constraint on the formation redshift is weaker if Omega_Lambda>0: z_form>1.7 if Omega_m=0.3 and Omega_Lambda=0.7. At present the limiting factor in constraining z_form and Omega from the observed luminosity evolution of early-type galaxies is the poor understanding of the IMF. We find that if Omega_m=1 the IMF must be significantly steeper than the Salpeter IMF (x>2.6).Comment: To be published in ApJ Letters, Volume 504, September 1, 1998. 5 pages, 4 figure

Analyses of H2O2 production in time during wound healing

Reactive Oxygen Species (ROS) have been traditionally con- sidered as toxic species due to their capacity to damage macromolecules. However, their deleterious effect is lim- ited to high concentrations. At lower levels, further studies have shown that at least hydrogen peroxide (H2O2) acts as a second messenger and results crucial for basic biological functions. Wound healing is one of those: in several animal models, this molecule is emitted in cellular wound margins, leading to neutrophil chemoattraction, while inducing epithe- lial cell migration during skin regeneration. Nevertheless, there are no references to this phenomenon in human ex- perimental set-ups. In this study, human keratinocyte cells (HaCaT), previously modified to express a H2O2-specific ra- tiometric fluorescent sensor (HyPer7) were monitored using live imaging after generating a mechanical-like injury. The time evolution ratio of the probe and the gap area were mea- sured for both cells near the margin and for topologically secondary cells, establishing a relationship between cytosolic H2O2 fluxes and the process of refilling a wound. In addition, comparison of movement rates between HyPer7-expressing and non-expressing HaCaT cells demonstrated a profound dependency of H2O2 availability for the process to occur.This project is the result of previous work carried out by exceptional scientists in the redox field and has been developed in the UC3M facility core CleanRooms for Bioengineering. Financial support was provided by the Madrid Government (Comunidad de Madrid) under the Multiannual Agreement with UC3M in the line of ”Research Funds for Beatriz Galindo Fellow- ships” (REDOXSKIN-CM-UC3M), and in the context of the V PRICIT (Regional Programme of Research and Technological Innovation”, and from “Proyectos de I + D + I” (PID2020-114230 GA-I00) funded by MCIN/AEI/10.13039/501100011033/

The Nature of Star Formation in Lensed Galaxies at High Redshift

We present near-infrared photometry of all available gravitationally lensed ‘arcs’ with spectroscopic redshifts. By combining this photometry with optical data, we find that the bulk of the systems with z ~ 1 are intrinsically blue across the rest-frame spectral region 2000 Å to 1 μm. Using a combination of optical and optical-infrared colours, we demonstrate that these systems cannot be blue by virtue of a secondary burst of star formation superimposed on an evolved population, but we are unable to distinguish directly between major star formation events in a generic young galaxy and an extended era of constant star formation typical of late-type spirals. Using various arguments, we conclude that our arcs represent modest gravitational magnification of typical field galaxies. Consequently, if the star formation seen is representative of that in field galaxies at z ≥ 1, the absence of high-redshift galaxies in current deep spectroscopic surveys to bJ≃24bJ≃24 supports the hypothesis that the bulk of the star formation in normal galaxies occurred over an extended era up to the epoch corresponding to z ~ 1