A simplified description of the evolution of organic aerosol composition in the atmosphere

Organic aerosol (OA) in the atmosphere consists of a multitude of organic species which are either directly emitted or the products of a variety of chemical reactions. This complexity challenges our ability to explicitly characterize the chemical composition of these particles. We find that the bulk composition of OA from a variety of environments (laboratory and field) occupies a narrow range in the space of a Van Krevelen diagram (H: C versus O:C), characterized by a slope of similar to-1. The data show that atmospheric aging, involving processes such as volatilization, oxidation, mixing of air masses or condensation of further products, is consistent with movement along this line, producing a more oxidized aerosol. This finding has implications for our understanding of the evolution of atmospheric OA and representation of these processes in models. Citation: Heald, C. L., J. H. Kroll, J. L. Jimenez, K. S. Docherty, P. F. DeCarlo, A. C. Aiken, Q. Chen, S. T. Martin, D. K. Farmer, and P. Artaxo (2010), A simplified description of the evolution of organic aerosol composition in the atmosphere, Geophys. Res. Lett., 37, L08803, doi: 10.1029/2010GL042737.

Actitudes hacia la lengua náhuatl : Un estudio sociolingüístico con jóvenes de la Ciudad deMéxico.

Nahuatl is one of the indigenous languages in Mexico that is at risk of falling out of use. The research in the last years have showed that this occurs due to the low amount of Nahuatl speakers and the social stigma and discrimination towards the indigenous peoples, among other factors.The studies of language attitudes are relevant when making attempts to revitalize a language. As Mexico City authorities have considered to implement a revitalization project, we wanted to approach the real situation of Nahuatl in that city. Our purpose was to measure the attitudes of young people towards this language. By using a direct method –a questionnaire- we asked two groups of students if they agreed or disagreed with some items about Nahuatl and its speakers. One group had contact with Nahuatl speakers and but not the other one. We compared the results and they showed that the students who have contact with Nahuatl have more positive attitudes than those who don’t have any contact with it. This study also revealed that the reason why the first group showed positive attitudes was solidarity with the Nahuatl speakers. However, the both groups considered that speaking or learning Nahuatl cannot contribute to raise their status in the Mexican society.

A SUGGESTION ON THE PAIR OF QSO TRIPLETS 1130+106 (B,A,C), (X,Y,Z)

The alignment of a pair of QSO triplets discovered by Arp and Hazard are tentatively explained by a combination of (I) the idea of quasar ejection by galaxies; (II) a construction by Narlikar suggesting a common origin for the six images; and (III) a nontrivial topology of cosmic space.

Preliminary Overview of the Economies of Latin America and the Caribbean 2001

Includes bibliography

Preliminary Overview of the Economies of Latin America and the Caribbean 2002

Includes bibliography

Preliminary Overview of the Economies of Latin America and the Caribbean 2003

Includes bibliography

Preliminary Overview of the Economies of Latin America and the Caribbean 2004

Includes bibliography

Preliminary Overview of the Economies of Latin America and the Caribbean 2005

Includes bibliography

Foreign Investment in Latin America and the Caribbean 1999

Includes bibliography

Equity, development and citizenship: abridged edition

Includes bibliography

Sustainable development: changing production patterns, social equity and the environment

Includes bibliography

Regional Panorama: Latin America. Megacities and sustainability

Includes bibliography