Informal Education. Sociocultural Expression. and Symbolic Meaning in Popular Immigration Music Text

One February morning as I noted the events of the primary school talent show, a sixth-grade boy belted out this song made popular in two countries by the Mexican rock group, Los Bukis. It was 1987, and I was doing fieldwork in a rural Mexican immigrant-sending community I call San Felipe, for an ethnography of families and their children who emigrated from Mexico to the United States[2

The Contribution of Cosmic Rays Interacting With Molecular Clouds to the Galactic Center Gamma-Ray Excess

The Fermi-LAT data appear to have an excess of gamma rays from the inner 150 pc of the Galactic Center. The main explanations proposed for this are: an unresolved population of millisecond pulsars (MSPs), dark matter (DM) annihilation, and nonthermal bremsstrahlung produced by a population of electrons interacting with neutral gas in molecular clouds. The first two options have spatial templates well fitted by the square of a generalized Navarro-Frenk-White (NFW) profile with inner slope $\gamma=1.2$. We model the third option with a 20-cm continuum emission Galactic Ridge template. A template based on the HESS residuals is shown to give similar results. The gamma-ray excess is found to be best fit by a combination of the generalized NFW squared template and a Galactic Ridge template. We also find the spectra of each template is not significantly affected in the combined fit and is consistent with previous single template fits. That is the generalized NFW squared spectrum can be fit by either of order 1000 unresolved MSPs or DM with mass around 30 GeV, a thermal cross section, and mainly annihilating to $b \bar{b}$ quarks. While the Galactic Ridge continues to have a spectrum consistent with a population of nonthermal electrons whose spectrum also provides a good fit to synchrotron emission measurements. We also show that the current DM fit may be hard to test, even with 10 years of Fermi-LAT data, especially if there is a mixture of DM and MSPs contributing to the signal, in which case the implied DM cross section will be suppressed.Comment: 14 pages, 6 figures, minor changes, matches PRD published versio

Remittances, Migration and Informality in Mexico. A Simple Model

In this paper, we analyse the possible channels through which informality, remittances and migration could interact and consequently affect growth in Mexico. In order to do so, we develop a simple endogenous growth model that allows for remittances and the coexistence of the formal and informal sector in the production function. In the literature, there is no agreement regarding the effects of the informal sector on economic growth. Moreover, thanks to globalization, migration and remittances have increased significantly their macroeconomic weight, renewing interest in studying the interactions that these variables might have, especially in developing countries like Mexico, where remittances are the third source of income after oil and tourism revenues. Our model shows that remittances play a crucial role on enhancing the Mexican resource constraint, while the possibility of migration in the informal sector drains the aggregate labor force. However, the magnitude of potential remittances may offset this loss, thus having an overall positive effect on economic growth.Growth; Informal Sector; Migration; Remittances

The Dynamics of Parallel Economies. Measuring the Informal Sector in México

The existence of parallel economies that operate in the shadows of informality within most Latin American countries is widely recognized by the economic literature. However, its composition, size and effects on economic growth are still open questions. In this paper, we estimate the size and the evolution of the Mexican informal economy in the last three decades using a vector error correction model. In addition to the standard explanatory variables traditionally used in the currency demand approach, we include remittances given their relevance in the Mexican economic system. The results indicate that informality prior to the late 1980’s accounted for at least two thirds of GDP, while stabilizing around one third of GDP in the last decade. Furthermore, our estimates provide evidence of a positive long run relationship between informality and economic growth.Informal Sector; currency demand; VEC; Remittances

Item statistics derived from three-option versions of multiple-choice questions are usually as robust as four- or five-option versions: implications for exam design.

Different versions of multiple-choice exams were administered to an undergraduate class in human physiology as part of normal testing in the classroom. The goal was to evaluate whether the number of options (possible answers) per question influenced the effectiveness of this assessment. Three exams (each with three versions) were given to each of two sections during an academic quarter. All versions were equally long, with 30 questions: 10 questions with 3 options, 10 questions with 4, and 10 questions with 5 (always one correct answer plus distractors). Each question appeared in all three versions of an exam, with a different number of options in each version (three, four, or five). Discrimination (point biserial and upper-lower discrimination indexes) and difficulty were evaluated for each question. There was a small increase in difficulty (a lower average score on a question) when more options were provided. The upper-lower discrimination index indicated a small improvement in assessment of student learning with more options, although the point biserial did not. The total length of a question (number of words) was associated with a small increase in discrimination and difficulty, independent of the number of options. Quantitative questions were more likely to show an increase in discrimination with more options than nonquantitative questions, but this effect was very small. Therefore, for these testing conditions, there appears to be little advantage in providing more than three options per multiple-choice question, and there are disadvantages, such as needing more time for an exam