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

Background and Objectives: Apocynaceae are one of the most species diverse groups of Mexico with numerous contributions to understand its systematics and distribution. However, some taxa are little known, as in the case of Odontadenia macrantha. A description, new distribution records, and conservation status of O. macrantha in Mexico are presented.Methods: Based on detailed observation of specimens from different herbaria and taxonomic literature, a description of the taxon and a key to morphologically and geographically close species is presented. In addition, an assessment of the conservation status of the species in Mexico, based on the IUCN criteria, and a distribution map are provided.Key results: The presence of this species in Tabasco and Veracruz extends its distribution further northwards. Additionally, these records provided new types of vegetation in which the species grows, such as tropical rain forest, tropical forest with Curatella, tropical deciduous forest and Quercus forest. Odontadenia macrantha is a taxon of variable morphology, which is corroborated here, because it has smaller corollas than the individuals of southern populations. Here is suggested to place this species in the category of Endangered (EN C2ai) for being restricted to a small tropical area with a high anthropogenic activity and few individuals in the observed populations.Conclusions: These new records suggest that the constant review of biological collections to maintain knowledge on taxa updated is needed. In addition, collection activities should be continued in the vegetation remnants of Tabasco and Veracruz.

Background and Aims: Light and water are resources that limit the germination and growth of vascular plants in forests and the establishment process significantly influence the species distribution. For this reason, we evaluated whether sympatric ferns Blechnum appendiculatum and B. schiedeanum (Blechnaceae) differ in habitat preference and if their germination requirements may help explain their distribution in a mountain mesophyllous forest.Methods: Spores were exposed to light quality, amount of light and water potential treatments. The frequency of sporophytes of both species and the proportion of light received in the forest was also recorded.Key results: It was found that both species did not germinate in darkness and few spores did so with far-red wavelength compared to white light. The spore sprout was promoted with the increase of light intensity, and 0.04 µmol m-2 s-1 light was sufficient so this was more than 60% in both species. The decrease in water availability reduced the germination, but B. appendiculatum showed greater ability to withstand water scarcity to -1.05 MPa. Blechnum schiedeanum was abundant in environments with relatively closed canopy while B. appendiculatum occurred more frequently on the forest border.Conclusions: Germination requirements were partially related to habitat preference of the species. Blechnum schiedeanum seems to be more shade tolerant than B. appendiculatum.

Background and Aims: The genus Scutellinia is cosmopolitan. Seven species have been reported in Mexico. A partial taxonomic revision of the genus Scutellinia in the country is presented.Methods: Seven species were studied, using traditional mycological techniques.Key results: Three species are cited for the first time in the country: Scutellinia balansae, S. colensoi and S. pennsylvanica. The main characteristics used for species identification in this study are marginal hairs and the ascospore ornamentation. Taxonomic descriptions of the three new records and previously reported species for the country are realized.Conclusions: The taxonomic knowledge of Scutellinia in Mexico remains scarce, so the development of more studies focused on the fungal systematic in the country is necessary.

Background and Aims: Castilleja nervata and C. tenuiflora var. xylorrhiza were reported for 11 and five states of Mexico, respectively. The aim of this study was to determine the morphological characters of C. nervata in order to differentiate it from C. arvensis, to identify C. tenuiflora var. xylorrhiza as part of the C. tenuiflora complex and separate the latter from C. integrifolia var. integrifolia, as well as showing the geographic distribution and documenting the morphological similitude of these taxa.Methods: Herbaria specimens were revised and the taxa were collected, in addition to measuring and characterizing the morphological structures of the specimens found in the National Park “Cañón del Río Blanco”, which were determined based on literature.Key results: Two taxa of the genus Castilleja unreported previously for the flora of the state of Veracruz, Mexico were identified. Two comparative tables for the identification of the taxa corresponding to the C. tenuiflora complex and for distinguishing between C. arvensis y C. nervata are presented. Photographs and a map of distribution of the new records are also provided.Conclusions: These taxa belong to the 10 species and eight varieties of the genus Castilleja present in Veracruz. Additionally, we recommend to revise the genus in other Mexican states and to continue the botanical exploration of the National Park “Canón del Río Blanco”.

Not applicable.

The research formed part of a national project whose general purpose is to “Create a spectral signatures catalog nationwide, divided by region (according to National Plan / Country Vision) and characterize land cover according to the FAO classification system, using ASD FieldSpec Handheld with a visible-near infrared (VNIR) range” to reduce errors by atmospheric dispersion and particulate matter as well as ground radiometric contribution. It started from the fact that the main problem is the lack of a spectral library of land cover, the National Project of Spectral Signatures has as general hypothesis that: The spectral signatures of different land cover acquired in field with a spectroradiometer are similar to the orbital spectral signatures of the image corrected by Rayleigh scattering, as long as the image has been acquired at the same observation date. As results, Pine Forest, Thicket, Agriculture, Pasture and Soil spectral signatures were obtained. For dominant vegetable toppings Normalized Difference Vegetation Index was applied to identify the intensity of biomass regarding phenological conditions. At the same time an adjustment to soil conditions was performed to identify the contribution of background reflectance (ground) introduced into the spectral signature of vegetation. In the analysis of the correlation between radiometric measures for image corrected atmospherically and field spectroradiometry, perform with both coverage that provided the most difficult separation, cafetal and thicket, they provided a high correlation coefficient, with a R2 of 0.99 in both cases, which proved the hypothesis. The study concluded that spectral signatures are useful to calibrate images without radiometric corrections.Revista Ciencias Espaciales, Vol.7(1) 2014, 76-96

Transits of Venus are events of great interest to science. They occur when the planet Venus is aligned between Earth and the Sun, producing for us visual effect that a very small black object passes through the solar surface. His understanding, from the earliest times was linked to the knowledge of the structure and dimensions of the solar system. The frequency with which they occur can be separated up to more than 100 years, reason why becomes increasingly rare events whenever they return to be visible, find scientists of different centuries with new instruments and more sophisticated technologies. In this paper, we make a historical review from when the earliest occurrence of a transit of Venus was predicted further documenting sometimes could be observed by astronomers from different latitudes of the planet, describing the circumstances, limitations, equipment and places they allowed to register and document these observations. The final part describes the great challenge that Honduras has represented, particularly for the Faculty of Space Sciences through its Department of Astronomy and Astrophysics, get to inform people of the type of astronomical event observed in June 2012, getting explained the more people become interested in observing safely, and equally important, an image of how national astronomers observed, leaving a legacy of reference for astronomers in 2125 it will see again.Revista Ciencias Espaciales, Vol.5(2) 2012, 5-19

Wildlife, especially birds, represent a danger for aviation especially in environments that have vegetation, water or power supplies for animals that may provoke incidents or accidents in aviation operations. The episodes especially of accidents caused by animals not add large numbers of cases in the aviation industry, but when they cause multibillion-dollar losses and even deaths, hence the importance of examining the phenomenon. In particular, this paper proposes a characterization of attraction sites of wildlife potentially affected to aircraft operations at the airport Toncontin and his perimeter area.This research is limited to the collection of some of the abundant literature on the subject and proposed a methodological elements that can help frame the issue of endangered bird and wildlife in the defined area; to have a study incorporating field data requires more time and especially collaboration throughout the research process integrated by specialists in the field of biology that delve into a number of issues that were just mentioned. It is shown that the main animal risk in Toncontin International Airport is the Coragyps atratus (zopilote); nevertheless are also a risk other species of smaller size and weight that reach the airport in search of food, water and shelter.Revista Ciencias Espaciales, Vol. 7(2) 2014, 96-108

This paper presents the results of the study, “Characterization of radio interference and noise floor at 1420 MHz Frequency” and this study is of primary importance in the pre-implementation stages of a radio telescope.In our country there has been no study of this type, at any frequency or range of frequencies allocated to the radio astronomy service, service which was jointly defined by the International Astronomical Union and the International Telecommunication Union (IAU and ITU, respectively).As primary endpoint, the radio conditions in Tegucigalpa, specifically in the Central American Astronomical Observatory of Suyapa (OACS), or in other words, were determined radio environment that will be expose any signal coming from celestial object , emitted at 1420 MHz frequency (λ = 21 cm).Data were collected through Radio Frequency Interference monitoring techniques (RFI), established in the “Spectrum Monitoring Handbook” published by ITU in 2011 and with the use of certified equipment by ITU for RFI studies.The conclusions and recommendations are based on the provisions issued by ITU for radio astronomy and analysis of radio conditions at the OACS.The study showed that the location of the Astronomical Observatory of Suyapa (OACS) has a very high level or noise floor, about 12 dB above the sensitivity of the equipment used, however, signals from sources like the sun and the Milky Way, are feasible to be received with some confidence.Revista Ciencias Espaciales, Vol.7(1) 2014, 35-59

According to the Intergovernmental Panel on Climate Change Good Practice Guidance (IPCC GPG), remote sensing techniques are suitable for the estimation of carbon sinks, through the estimation of above ground biomass. In this work we used a Landsat time series to estimate the grass biomass in pasture areas in the Department of Olancho for the years 2010 and 2012. From the results of the estimation of biomass, we analyzed the evolution of carbon stocks. Field sampling of biomass were performed, as well as radiometry, in a plot located within the study site for the model calibration. We applied a linear regression model using field data and spectral indices for estimating the variable. EVI was the best index for biomass estimation (R2=0.87). A carbon fraction of 50% of the biomass was applied for the carbon stock estimation.Revista Ciencias Espaciales, Vol.7(1) 2014, 97-114