OBJECTIVE: To study the effect of different degrees of centrality on the carrying of identical group A streptococcus (GAS) clones in the nasopharynx of children from a Mexican public day-care center. MATERIAL AND METHODS: Nasopharyngeal cultures were performed in children…

Breast cancer research has yielded several important results including the strong susceptibility genes,BRCA1 and BRCA2 and more recently 19 genes and genetic loci that confer a more moderate risk.The pace of discovery is accelerating as genetic technology and computational methods…

New combinations are proposed here for 26 species and one variety belonging to 13 genera of Mexican Orchidaceae.These combinations are required to comply with current taxonomic concepts and ongoing revisionary treatment of the orchids of mexico. The collector and number…

The volatile composition of the leaves of Bursera velutina Bullock (Burseraceae) was determined by a gas chromatograph-mass spectrometer (GC-MS). the major component found was 2-phenylethanol (29.5%). This is the first report of 2-phenylethanol in the leaves of a species of…

Lophiaris tapiae Balam & Carnevali (Orchidaceae: Oncidiinae) is described and illustrated. The new species is known only from the Escarcega area, and the Candelaria and Palizada rivers margins in the state of Campeche, Mexico. It is compared with species of…

Autistic Spectrum Disorders (ASD) are developmental disorders with impairments in three broad domains: social interaction, communication and stereotypic movements and repetitive behavior. Their symptoms are complex, bizarre and most of them persistent, causing maladaptive and poor psychosocial adjustment. Early detection…

This article describes temperature and precipitation patterns in the region of Los Tuxtlas southern Veracruz (Mexico). The region is defined here as the volcanic landscape above 100 m elevation (except at the coast), and comprises 315 525 hectares, including the…

Tillandsia magnispica Espejo & López-Ferrari, known only from the state of Oaxaca, Mexico, in the municipalities of San Pedro el Alto and San Pedro Pochutla, is described and illustrated. The new taxon is compared with T. jaliscomonticola Matuda, a morphologically…

The name Didymaea alsinoides (Schltdl. & Cham.) Standl. has been incorrectly applied to a common and wide-ranging Mexican and Central American species whose correct identity is Didymaea Mexicana Hook. f. In this paper a lectotype is selected and designated for…

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…