OBJECTIVE: The aim of this study was to determine the prevalence of asymptomatic nasopharyngeal carriage of Streptococcus pneumoniae, which is a major factor in the transmission of this bacterium. MATERIAL AND METHODS: Nasopharyngeal cultures were performed on children attending 32…

Pinos volcanic complex is an uplifted area that exposes Mesozoic strata and mid-Tertiary volcanic and sedimentary rocks. Its stratigraphy, deformation style, and volcanism are characteristic of the Mesa Central region of central Mexico and the southeastern segment of the Sierra…

Significant changes in the isotopic composition of groundwater in the upper catchment of Rio Guanajuato, Mexico, were detected in two independent sets of samples for 3 % of the 1600 high-production wells in the area. Sampling was done in December…

In this paper we report the oldest geologic world record of Ptychodus mortoni, from the Vallecillo Member (Agua Nueva Formation), at Vallecillo, Nuevo León, northeastern Mexico. The presence of the ammonite Watinoceras coloradoense, allows the placement of the sediments of…

A complete description of Vallecillichthys multivertebratum Blanco and Cavin, 2003, is provided. This ichthyodectiform fish was collected in the Vallecillo Member of the Agua Nueva Formation (Upper Cretaceous: lower Turonian) at Vallecillo, Nuevo León State, northeastern Mexico. On the basis…

A new species of the Dahlibruchus genus is described and information is given about its bionomics and host plants, also are mentioned general aspects about the archeological site where the insect was found.

An isolated supraorbital horncore collected from the Olmos Formation near Múzquiz is among the longest ever found, and records the presence in this area of a very large ceratopsid. The specimen probably pertains to a chasmosaurine, but differs significantly from…

Monstera florescanoana (Araceae), a new species in section Monstera, endemic to central Veracruz, Mexico, is described and illustrated. This species appears to be most closely related to Monstera siltepecana Matuda and Monstera dubia (Kunth) Engl. et K. Krause.

Identification keys, diagnoses, hosts, and distribution data are provided for adults of the 26 species of Ixodes known from Mexico. Data are from specimens deposited in the Colección Nacional de Ácaros (CNAC), Instituto de Biología, Universidad Nacional Autónoma de México,…

The association between gastrointestinal H. pylori infection and thrombocytopenia was studied in a single institution in Mexico, over a 5-year period. In 99 individuals with H. pylori infection, the prevalence of thrombocytopenia was 14%, whereas in 23 consecutive patients with…