Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Determining the quality of wood is not a common research activity, due to ignorance of its effect on the overall quality of constructions. Wood quality can be considered as a combination of attributes that give it properties appropriate for specific uses. The wood used In this research experiment was donated by a local supplier in the City of Guanajuato. Mechanical properties, water content, and those characteristics necessary for visual grading and classification were judged according to Mexican standards. The analyzed sample easily complied with the requirements for class A, implying that it was of sufficient quality for use in the construction of houses, decorative details, and ramps.

This paper presents a review of information about new environmental technologies applied to urban development activities is organized and systematized. These technologies are justa portion of all technologies that can be applied to the development of cities, therefore, this paper is a presentation of the state of the art of new technologies being applied to sustainable urban development, which are mainly processes, precision tools, simulators, equipment, materials, and software and hardware, which facilitate the work of urban designers, architects and construction companies.

En este artículo se describe el diseño y los resultados obtenidos con una estrategia didáctica innovadora para el aprendizaje de la Estadística Actuarial en la licenciatura de Ciencias Actuariales y Financieras de la Universidad de Málaga. Mediante un uso intensivo de actividades no presenciales y elementos tecnológicos que favorecen el aprendizaje en movilidad se pretende potenciar el aprendizaje autónomo, colaborativo y contextualizado. Para ello se han diseñado, entre otras, actividades de identificación y asimilación de competencias, un laboratorio virtual de supervivencia basado en un simulador gráfico interactivo y un microportal para dispositivos iPhone y iPod touch de Apple.

En este artículo proponemos una práctica empírica para la asignatura de Comercio Internacional con la que los estudiantes puedan manejar estadísticas de comercio y acercarse así a la realidad del comercio mundial. El objetivo de la práctica es doble: por un lado, el estudiante aprende a interpretar y aplicar algunas teorías de comercio, extrayendo hipótesis contrastables empíricamente; por otro lado, se enfrenta a datos reales de comercio que debe tratar estadísticamente a fin y efecto de contrastar la validez de las predicciones teóricas

Hybridization between the cultivated sunflower Helianthus annuus and the wild species with ornamental potential Tithonia rotundifolia was performed. From three cultivated materials: AN-3, Primavera and HA 89, the only success was obtained with the public cultivated sunflower line HA 89 as female parent. The male parent was a T. rotundifolia population collected in the state of Guerrero, Mexico. A total of 826 well developed hybrid achenes were produced, with a rate of success of four in 1000 potential achenes. In a sample of 49 plants established in the experimental field, two phenotypic classes were observed: a) plants with many small inflorescenses, and b) plants with a single big head and a few or none axillary inflorescenses. Both types were morphologically characterized and showed a clearly hybrid morphology. Additionally, the AFLP-based DNA fingerprints were analyzed in a sample of ten familial trios, with an average of 28 polymorphisms per trio. The DNA fingerprinting analysis of the plants complemented the morphological study, allowed confirmation of the hybrid nature of the progenies and ruled out the partial hybridization phenomenon. All the hybrid plants showed sterility. From this work, it becomes clear that chromosomic manipulation or tissue culture techniques are needed to develop fertile hybrids with ornamental potential.

Fruit morphology (color, size and type) of 881 tree species (338 genera and 85 families) that inhabit the tropical rain forest in Mexico was assessed. We found 46 fruit types and about 52.7% of species had berries (212 species), drupes (163) or loculicidal capsules (89); ten fruit types were represented by just one species. The most abundant fruit colors were (n = 865 species) black (307 species; 35.5%), brown (227; 26.2%) and red (159; 18.4%). Berries were usually black (66%), drupes black (53.9%) or red (39.3%) and more than half of loculicidal capsules were brown (66.3%). Fruit length varied from 0.8 to 430 mm (mean 31.7 mm) and fruit width from 1 to 145 mm (mean 16.1 mm); these variables were positively correlated (r = 0.55, p < 0.05; n = 743 species). Berries, drupes and loculicidal capsules were small (mean size < 22 mm long), while legumes and camaras were longer (mean > 100 mm long). The largest numbers of fruit types per family was recorded for Rubiaceae (seven) and 47 of them displayed just one. Fruit type frequency and species per family were correlated (r = 0.58, p < 0.05; n = 85 families). Such correlation was not sustained at generic level, because 328 genera (97%) showed just one fruit type. Our results indicate that fruit morphological diversity of tree species is an important trait to understand the structure and composition of the tropical rain forest.

Esta contribución es parte de una serie de artículos cuyo objetivo es incrementar el conocimiento de los hongos anamorfos saprobios que proliferan en el bosque mesófilo de montaña en el estado de Veracruz. Se presentan las descripciones e imágenes de 25 especies. Todas ellas, excepto Helminthosporium solani, son nuevos reportes para México. Dictyochaeta tumidospora, Fusariella intermedia, Hyphodiscosia queenslandica y Dictyosporium digitatum no habían sido registradas desde su descripción original. Se incluyen datos de su distribución y sustratos en los que se han colectado.

Perymenium arriagae and P. sotoarenasii are described and illustrated as new species from central Queretaro. Both are shrubs of xerophilous habitat and habit, and are known from scarce collections, in spite of the fact that the area has been fairly intensively explored. Seemingly the two species are closely related to each other, although they conspicuously differ in the leaf margin and leaf base, as well as in the size of the involucres and in the color of the pales. Given the imperfect stage of taxonomic knowledge of the genus, it is difficult to define their relationships with any of the remaining groups of Perymenium.

Euphorbia spellenbergiana is described and illustrated as a new species. It belongs to subgenus Chamaesyce within which it is easily distinguished from similar species by its possession of undivided styles with capitate stigmas. This new species is endemic to Mexico and occurs from central western Chihuahua to northern Michoacán. Although widespread, it is highly habitat-specific and prospers only in the moist soil around ephemeral pools in pine-oak forest, grassland and pachycaulous scrub at elevations from 2100 to 2600 m.

It is sustained that scientific-technological culture is a necessary condition for democratic life in contemporary societies. This thesis is supported through two recent examined events in Mexico: sanitary emergency during 2009 spring due to an influenza outbreak, and transnational demand for transgenic corn open field sowing, due to a Biosecurity Genetically Modified Organisms Law whose regulations were modified. In both cases, political decision making and population participation would have been different, and closer to an authentic democratic society, if an adequate scientific- technological culture existed, permitting citizen participation in an informed way and collaborating in the construction of a proper scientific-technological culture, besides the idea of science and technology philosophy which is rejected, keeping it separated from an “analytical” and “humanistic” aspect. Both are necessary and should be integrated in an adequate science and technology philosophic conception, essential in current societies.