Inequality and Heterogeneous Returns to Education in Mexico (1992-2002)

Within the attempts to understand Mexican economic inequality, returns to education have received a great deal of attention. The driving question has been: why are Mexican wages so unequal? This paper argues that not only the distribution of human capital matters, but also sociodemographic variables, which have their own dynamics and complex interactions with the former. A three-equation maximum likelihood specification in which employment, hours worked and log-wages, as well as their joint variance matrix is proposed, generalizing the Mincerian specification. The resulting is a complex story, where income profiles depend upon particular characteristics.

HOUSEHOLD SIZE AND COMPOSITION IMPACTS ON MEAT DEMAND IN MEXICO: A CENSORED DEMAND SYSTEM APPROACH

The proposed paper adopts the censored demand system approach of Lee and Pitt (1986) to examine the structure of Mexican food demand. This approach uses the concept of virtual prices to explain specific purchase patterns. The contribution of our selected paper is the incorporation of the endogenous equivalence scale function proposed by Phlipps (1998) within this censored system. The contribution of this analysis is not only in terms of the use of an endogenous scaling function within a censored demand system, but we also will be use simulated maximum likelihood techniques which allows for the specification and estimation of significantly larger sized demand systems without the imposition of restrictive distributional assumptions on the equation error terms. We use a Gibbs sampling techniques to evaluate higher order truncated distributions required to implement the Lee and Pitt (1986) model specification.Demand and Price Analysis,

Elevated Plasma Endothelin-1 and Pulmonary Arterial Pressure in Children Exposed to Air Pollution

BackgroundControlled exposures of animals and humans to particulate matter (PM) or ozone air pollution cause an increase in plasma levels of endothelin-1, a potent vasoconstrictor that regulates pulmonary arterial pressure.ObjectivesThe primary objective of this field study was to determine whether Mexico City children, who are chronically exposed to levels of PM and O3 that exceed the United States air quality standards, have elevated plasma endothelin-1 levels and pulmonary arterial pressures.MethodsWe conducted a study of 81 children, 7.9 ± 1.3 years of age, lifelong residents of either northeast (n = 19) or southwest (n = 40) Mexico City or Polotitlán (n = 22), a control city with PM and O3 levels below the U.S. air quality standards. Clinical histories, physical examinations, and complete blood counts were done. Plasma endothelin-1 concentrations were determined by immunoassay, and pulmonary arterial pressures were measured by Doppler echocardiography.ResultsMexico City children had higher plasma endothelin-1 concentrations compared with controls (p < 0.001). Mean pulmonary arterial pressure was elevated in children from both northeast (p < 0.001) and southwest (p < 0.05) Mexico City compared with controls. Endothelin-1 levels in Mexico City children were positively correlated with daily outdoor hours (p = 0.012), and 7-day cumulative levels of PM air pollution < 2.5 μm in aerodynamic diameter (PM2.5) before endothelin-1 measurement (p = 0.03).ConclusionsChronic exposure of children to PM2.5 is associated with increased levels of circulating endothelin-1 and elevated mean pulmonary arterial pressure

Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).

Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≥1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≤6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)

Caribbean-Wide, Long-Term Study of Seagrass Beds Reveals Local Variations, Shifts in Community Structure and Occasional Collapse

The CARICOMP monitoring network gathered standardized data from 52 seagrass sampling stations at 22 sites (mostly Thalassia testudinum-dominated beds in reef systems) across the Wider Caribbean twice a year over the period 1993 to 2007 (and in some cases up to 2012). Wide variations in community total biomass (285 to >2000 g dry m−2) and annual foliar productivity of the dominant seagrass T. testudinum (2000 g dry m−2) were found among sites. Solar-cycle related intra-annual variations in T. testudinum leaf productivity were detected at latitudes > 16°N. Hurricanes had little to no long-term effects on these well-developed seagrass communities, except for 1 station, where the vegetation was lost by burial below ∼1 m sand. At two sites (5 stations), the seagrass beds collapsed due to excessive grazing by turtles or sea-urchins (the latter in combination with human impact and storms). The low-cost methods of this regional-scale monitoring program were sufficient to detect long-term shifts in the communities, and fifteen (43%) out of 35 long-term monitoring stations (at 17 sites) showed trends in seagrass communities consistent with expected changes under environmental deterioration.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias del Mar y Limnología (CIMAR

Returns to Schooling, Institutions and Heterogeneous Diploma Effects: An Expanded Mincerian Framework applied to Mexico

We hypothesize two sources for sheepskin effects - signaling, and diplomas tied to jobs with downwards rigid wages. These theories have implications for diploma effects not only in the first, but also the second moments of the Mincerian earnings distribution that we are able to identify using a flexible econometric specification. Idiosyncrasies in Mexican labor market and educational institutions offer a natural experiment on which to train this methodology and test these theories. Correcting for heterogeneity in diplomas, we find no evidence of sheepskin effects, except on graduation from primary school. We find compelling evidence that returns to education (in both moments) are linked with labor market institutions and job-specific diplomas in the manner we hypothesize. Our econometric structure corrects for sample selectivity due to unemployment and allows us to observe behavior on the quantity axis of a labor market segmented by sheepskin effects. We also analyze the covariates of hours worked which helps to explain observed patterns in hourly earnings