13,148 research outputs found
The impact of income adjustments in the Casen Survey on the measurement of inequality in Chile
The adjustment of the information obtained from household surveys to make the figures compatible with National Accounts is a non-standard and potentially questionable practice given that it alters the structure of income distribution. This paper analyzes the sensitivity of inequality and poverty indicators to the adjustments made by ECLAC so as to enable a consistency between what is reported by the CASEN survey and the National Accounts figures in Chile. The results reveal that this leads to important changes in the top-end of the distribution and to an overestimation in the main inequality indicators in Chile. Chile looks more unequal in international relative terms due to this adjustment.Inequality, Poverty, Income adjustment, Chile
The Persistence of Memory, or How the X-Ray Spectrum of SNR 0509-67.5 Reveals the Brightness of its Parent Type Ia Supernova
We examine the dynamics and X-ray spectrum of the young Type Ia supernova
remnant 0509-67.5 in the context of the recent results obtained from the
optical spectroscopy of its light echo. Our goal is to estimate the kinetic
energy of the supernova explosion using Chandra and XMM-Newton observations of
the supernova remnant, thus placing the birth event of 0509-67.5 in the
sequence of dim to bright Type Ia supernovae. We base our analysis on a
standard grid of one-dimensional delayed detonation explosion models, together
with hydrodynamic and X-ray spectral calculations of the supernova remnant
evolution. From the remnant dynamics and the properties of the O, Si, S, and Fe
emission in its X-ray spectrum we conclude that 0509-67.5 was originated ~400
years ago by a bright, highly energetic Type Ia explosion similar to SN 1991T.
Our best model has a kinetic energy of 1.4x10E51 erg and synthesizes 0.97 Msun
of 56Ni. These results are in excellent agreement with the age estimate and
spectroscopy from the light echo. We have thus established the first connection
between a Type Ia supernova and its supernova remnant based on a detailed
quantitative analysis of both objects.Comment: 10 pages, 9 figures, plus an exclusive astro-ph-only Appendix; ApJ in
press, companion paper to Rest et al. 0
Vanishing of local non-Gaussianity in canonical single field inflation
We study the production of observable primordial local non-Gaussianity in two
opposite regimes of canonical single field inflation: attractor (standard
single field slow-roll inflation) and non attractor (ultra slow-roll
inflation). In the attractor regime, the standard derivation of the
bispectrum's squeezed limit using co-moving coordinates gives the well known
Maldacena's consistency relation . On the other hand,
in the non-attractor regime, the squeezed limit offers a substantial violation
of this relation given by . In this work we argue that,
independently of whether inflation is attractor or non-attractor, the size of
the observable primordial local non-Gaussianity is predicted to be
(a result that was already understood to hold in the case of
attractor models). To show this, we follow the use of the so-called Conformal
Fermi Coordinates (CFC), recently introduced in the literature. These
coordinates parametrize the local environment of inertial observers in a
perturbed FRW spacetime, allowing one to identify and compute gauge invariant
quantities, such as -point correlation functions. Concretely, we find that
during inflation, after all the modes have exited the horizon, the squeezed
limit of the 3-point correlation function of curvature perturbations vanishes
in the CFC frame, regardless of the inflationary regime. We argue that such a
cancellation should persist after inflation ends.Comment: 27 pages, v2:matches published version(JCAP
The Transition to College Process in PR-CETP Scholars
This article describes a study about the experiences of a group of students during the transition from high school to college. The students are future teachers who evidenced a high level of academic achievement in high school and received merit scholarships from the Puerto Rico Collaborative for Excellence in Teacher Preparation (PR-CETP). Two groups of students were compared: those who sustained a high GPA during their freshman year, and those who did not and, therefore, no longer qualified for the scholarship. The study was carried out through focused interviews with eight students, from three universities, four of whom maintained the scholarship and four who did not. Findings indicate that the main problems encountered were academic and social, and that the students received support from their families during the entire process. Regarding formal support, they pointed out that they felt highly satisfied with the services provided by PR-CETP and the universities, but they also pointed out (particularly those who lost the scholarship) that they needed additional services from the universities. They suggested, for example, better tutoring, and social activities among the scholars. The interviewed students, in general, consider that they faced the transition successfully since most of them described their academic, emotional, and social status as satisfactory at the time of the interviews
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