Technical Note: Ensuring consistent, global measurements of short-lived halocarbon gases in the ocean and atmosphere

Very short-lived halocarbons are significant sources of reactive halogen in the marine boundary layer, and likely in the upper troposphere and lower stratosphere. Quantifying ambient concentrations in the surface ocean and atmosphere is essential for understanding the atmospheric impact of these trace gas fluxes. Despite the body of literature increasing substantially over recent years, calibration issues complicate the comparison of results and limit the utility of building larger-scale databases that would enable further development of the science (e.g. sea-air flux quantification, model validation, etc.). With this in mind, thirty-one scientists from both atmospheric and oceanic halocarbon communities in eight nations gathered in London in February 2008 to discuss the scientific issues and plan an international effort toward developing common calibration scales (http://tinyurl.com/c9cg58). Here, we discuss the outputs from this meeting, suggest the compounds that should be targeted initially, identify opportunities for beginning calibration and comparison efforts, and make recommendations for ways to improve the comparability of previous and future measurements.

Hall conditions for edge-weighted bipartite graphs

A weighted variant of Hall's condition for the existence of matchings is shown to be equivalent to the existence of a matching in a lexicographic product. This is used to introduce characterizations of those bipartite graphs whose edges may be replicated so as to yield semiregular multigraphs or, equivalently, semiregular edge-weightings. Such bipartite graphs will be called semiregularizable. Some infinite families of semiregularizable trees are described and all semiregularizable trees on at most 11 vertices are listed. Matrix analogues of some of the results are mentioned and are shown to imply some of the known characterizations of regularizable graphs.

Citizenship training in school from the perspective of future primary education teachers

The aim of this paper is to recognize the images that prospective elementary school teachers have about citizenship and citizenship education in school. The qualitative methodology with an ethnographic approach is used for that deep interview of ethnographic kind and analysis of institutional documents, for example, curricula, course syllabus and graduated profi le. The revision of documents helps to a better understanding of discourses. The analysis of the corpus obtained after the application of the paradigm of codifi cation proposed in the established theory. As the principal fi ndings we way point out that the concept of citizens that is common among prospective elementary school teachers is reduced to the school environment because they consider that the promotion of citizenship helps to the incorporation of children to society, thus reproducing a propaedeutic view of education.