Effects of quantized fields on the spacetime geometries of static spherically symmetric black holes

Analytic approximations for the stress-energy of quantized fields in the Hartle-Hawking state in static black hole spacetimes predict divergences on the event horizon of the black hole for a number of important cases. Such divergences, if real, could substantially alter the spacetime geometry near the event horizon, possibly preventing the black hole from existing. The results of three investigations of these types of effects are presented. The first involves a new analytic approximation for conformally invariant fields in Reissner-Nordstrom spacetimes which is finite on the horizon. The second focuses on the stress-energy of massless scalar fields in Schwarzschild-de Sitter black holes. The third focuses on the stress-energy of massless scalar fields in zero temperature black hole geometries that could be solutions to the semiclassical backreaction equations near the event horizon of the black hole.Comment: 5 pages. To appear in the "Proceedings of the Eleventh Marcel Grossmann Meeting on General Relativity", July 2006, Berlin, German

First-Round Impacts of the 2008 Chilean Pension System Reform

Chile’s innovative privatized pension system has been lauded as possible model for Social Security system overhauls in other countries, yet it has also been critiqued for not including a strong safety net for the uncovered sector. In response, the Bachelet government in 2008 implemented reforms to rectify this shortcoming. Here we offer the first systematic effort to directly evaluate the reform’s impacts, focusing on the new Basic Solidarity Pension for poor households with at least one person age 65+. Using the Social Protection Survey, we show that targeted poor households received about 2.4 percent more household annual income, with little evidence of crowding-out of private transfers. We also suggest that recipient household welfare probably increased due to slightly higher expenditures on basic consumption including healthcare, more leisure hours, and improved self-reported health. While measured short-run effects are small, follow-ups will be essential to gauge longer-run outcomes.

SPITZER observations of the λ Orionis cluster. II. Disks around solar-type and low-mass stars

We present IRAC/MIPS Spitzer Space Telescope observations of the solar-type and the low-mass stellar population of the young (~5Myr) λ Orionis cluster. Combining optical and Two Micron All Sky Survey photometry, we identify 436 stars as probable members of the cluster. Given the distance (450 pc) and the age of the cluster, our sample ranges in mass from 2 M_⊙ to objects below the substellar limit. With the addition of the Spitzer mid-infrared data, we have identified 49 stars bearing disks in the stellar cluster. Using spectral energy distribution slopes, we place objects in several classes: non-excess stars (diskless), stars with optically thick disks, stars with “evolved disks” (with smaller excesses than optically thick disk systems), and “transitional disk” candidates (in which the inner disk is partially or fully cleared). The disk fraction depends on the stellar mass, ranging from ~6% for K-type stars (R_C − J 4). We confirm the dependence of disk fraction on stellar mass in this age range found in other studies. Regarding clustering levels, the overall fraction of disks in the λ Orionis cluster is similar to those reported in other stellar groups with ages normally quoted as ~5Myr

Compactness for Holomorphic Supercurves

We study the compactness problem for moduli spaces of holomorphic supercurves which, being motivated by supergeometry, are perturbed such as to allow for transversality. We give an explicit construction of limiting objects for sequences of holomorphic supercurves and prove that, in important cases, every such sequence has a convergent subsequence provided that a suitable extension of the classical energy is uniformly bounded. This is a version of Gromov compactness. Finally, we introduce a topology on the moduli spaces enlarged by the limiting objects which makes these spaces compact and metrisable.Comment: 38 page

DEMANDA DE TRABAJO DE LA INDUSTRIA MAQUILADORA DE CIUDAD JUAREZ

THIS WORK EXPOSE THE DETERMINAT'S FACTORS OF THE CIUDAD JUAREZ LABOR'S DEMAND OF THE MAQUILADORA INDUSTRY. ESTE TRABAJO DESARROLLA UN MODELO TEORICO DE COMPORTAMIENTO DE LA DEMANDA DE TRABAJO, APLICADO A LA INDUSTRIA MAQUILADORA SITUADA EN LA CIUDAD FRONTERIZA DE CD. JUAREZ MEXICO.MAQUILADORA, REGIONAL GROWTH

Resonance expansions in quantum mechanics

The goal of this contribution is to discuss various resonance expansions that have been proposed in the literature.Comment: 10 pages and 1 figure; presented at the Istanbul workshop on pseudo-Hermitian Hamiltonian

Isosorbide dinitrate, with or without hydralazine, does not reduce wave reflections, left ventricular hypertrophy, or myocardial fibrosis in patients with heart failure with preserved ejection fraction

Background-Wave reflections, which are increased in patients with heart failure with preserved ejection fraction, impair diastolic function and promote pathologic myocardial remodeling. Organic nitrates reduce wave reflections acutely, but whether this is sustained chronically or affected by hydralazine coadministration is unknown. Methods and Results-We randomized 44 patients with heart failure with preserved ejection fraction in a double-blinded fashion to isosorbide dinitrate (ISDN; n=13), ISDN+hydralazine (ISDN+hydral; n=15), or placebo (n=16) for 6months. The primary end point was the change in reflection magnitude (RM; assessed with arterial tonometry and Doppler echocardiography). Secondary end points included change in left ventricular mass and fibrosis, measured with cardiac magnetic resonance imaging, and the 6-minute walk distance. ISDN reduced aortic characteristic impedance (mean baseline=0.15 [95% CI, 0.14-0.17], 3 months=0.11 [95% CI, 0.10-0.13], 6 months=0.10 [95% CI, 0.08-0.12] mmHg/mL per second; P=0.003) and forward wave amplitude (P-f, mean baseline=54.8 [95% CI, 47.6-62.0], 3 months=42.2 [95% CI, 33.2-51.3]; 6 months=37.0 [95% CI, 27.2-46.8] mmHg, P=0.04), but had no effect on RM (P=0.64), left ventricular mass (P=0.33), or fibrosis (P=0.63). ISDN+hydral increased RM (mean baseline=0.39 [95% CI, 0.35-0.43]; 3 months=0.31 [95% CI, 0.25-0.36]; 6 months=0.44 [95% CI, 0.37-0.51], P=0.03), reduced 6-minute walk distance (mean baseline=343.3 [95% CI, 319.2-367.4]; 6 months=277.0 [95% CI, 242.7-311.4] meters, P=0.022), and increased native myocardial T1 (mean baseline=1016.2 [95% CI, 1002.7-1029.7]; 6 months=1054.5 [95% CI, 1036.5-1072.3], P=0.021). A high proportion of patients experienced adverse events with active therapy (ISDN=61.5%, ISDN+hydral=60.0%; placebo=12.5%; P=0.007). Conclusions-ISDN, with or without hydralazine, does not exert beneficial effects on RM, left ventricular remodeling, or submaximal exercise and is poorly tolerated. ISDN+hydral appears to have deleterious effects on RM, myocardial remodeling, and submaximal exercise. Our findings do not support the routine use of these vasodilators in patients with heart failure with preserved ejection fraction

Galaxy populations in the Antlia cluster - III. Properties of faint early-type galaxies

(Abridge) We present a new analysis of the early-type galaxy population in the central region of the Antlia cluster, focusing on the faint systems like dwarf ellipticals (dE) and dwarf spheroidals (dSph). We confirm 22 early-type galaxies as Antlia members, using GEMINI-GMOS and MAGELLAN-MIKE spectra. Among them, 2 belong to the rare type of compact ellipticals (cE), and 5 are new faint dwarfs that had never been catalogued before. In addition, we present 16 newly identified low surface brightness galaxy candidates, almost half of them displaying morphologies consistent with being Antlia's counterparts of Local Group dSphs, that extend the faint luminosity limit of our study down to MB = -10.1 (BT = 22.6) mag. We built an improved CMR in the Washington photometric system, i.e. integrated T1 magnitudes versus (C - T1) colours, which extends \sim 4 mag faintwards the limit of spectroscopically confirmed Antlia members. When only confirmed early-type members are considered, this relation extends over 10 mag in luminosity with no apparent change in slope or increase in colour dispersion towards its faint end. The intrinsic colour scatter of the relation is compared with those reported for other clusters of galaxies; we argue that it is likely that the large scatter of the CMR, usually reported at faint magnitudes, is mostly due to photometric errors along with an improper membership/morphological classification. The distinct behaviour of the luminosity versus mean effective surface brightness relation at the bright and faint ends is analyzed, while it is confirmed that dE galaxies on the same relation present a very similar effective radius, regardless of their colour. The projected spatial distribution of the member sample confirms the existence of two groups in Antlia, each one dominated by a giant elliptical galaxy and with one cE located close to each giant.Comment: 19 pages, 9 figures, 5 tables. Accepted for publication in MNRA