The purpose of the present paper is to review the current knowledge about cholesterol gallstone disease. It is generally accepted that the formation of cholesterol gallstone requires three major pathogenic defects, namely, supersaturation, nucleation and crystal growth as well as…

These notes contain a series of ten lectures delivered at the ''Universidad Nacional Autonoma de Mexico'' on its ''Primer Seminario de K-Teoria Algebraica''. They provide an introduction to the subject as well as to the other expositions in this volume.…

The compressed basidiocarp of a fungus belonging to Geasteraceae (Lycoperdales, Gasteromycetes) was recovered from the plant-bearing Cenozoic strata of the Pie de Vaca Formation, Puebla, Mexico. The fossil specimen consists of an open exoperidium with ten triangular rays, and a…

Mimosoideae), Mimosa (Mimoseae, Mimosoideae), Lysiloma (Ingeae, Mimosoideae),and Sophora (Sophoreae, Papilionoideae). Another fruit exhibits a combination of characters unknown among extant legumes, and although superficially similar to some species of Papilionoideae, it represents an extinct genus. The four identified genera are…

The Upper Cenozoic flora of the Pie de Vaca Formation, Puebla, Mexico, is yielding important elements that contribute to a more complete knowledge of the Tertiary floras of southern latitudes of North America. Among the most abundant plant organs in…

La evolución de las características ecológicas de las especies es uno de los temas más intensamente estudiados, pero su complejidad suele limitar estos estudios a evidencias indirectas de las adaptaciones reales de los organismos. Recientemente, métodos moleculares como los "micro-arrays"…

While birdsong is a model system for animal communication studies, our knowledge is derived primarily from the study of only one sex and is therefore incomplete. The study of song in a role-reversed species would provide a unique opportunity to…

For the first time for Mexican mycobiota the genus Cerinomyces Mar. is reported with the species C lagerheimii (Pat.) McNabb. This species only have been found in Ecuador (type locality), Brasil, United States and Venezuela. A review of different specimens…

In 1950, Tinbergen described the elicitation of offspring begging by the red spot on the bill of parent gulls, and this became a model system for behavioural studies. Current knowledge on colour traits suggests they can act as sexual signals…

Studies of tropical secondary forest succession face strong limitations due to the slow pace of succession and the time-consuming task of monitoring processes. The occurrence of tree rings in secondary forest trees may help expand our knowledge on succession in…