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546,196 artículos
Año:
2017
ISSN:
2215-2075, 0034-7744
Monge-Nájera, Julián; Ho, Yuh-Shan
Universidad de Costa Rica
Resumen
Guatemala, with 16 million inhabitants, is the largest economy of Central America and should have the largest scientific output of the region. To assess its productivity and impact, we analyzed the 3380 Guatemala articles included in the SCI-expanded in June, 2017. Most Guatemala documents are articles in English, deal with nutrition and health problems, and have a mean of 7.4 authors per article. Also in this particular database, citation lifespan is 40 years, and citations are higher for articles in English (twice more than those in Spanish), for reviews (mean 24 citations per review) and for studies resulting from international collaboration, which is done mostly with the USA and Mexico. The most productive institutions are the Center for Studies of Sensory Impairment CESSIAM, the universities of San Carlos and El Valle, and the Central American Nutrition Institute INCAP (but the INCAP has decreased productivity in recent years). The most productive researchers are N.W. Solomons, R. Bressani, L.G. Elías, C. Rolz and A. Cáceres. Guatemala represents a particular case in Central America because its high quality research is dependent on particular researchers rather than on institutions, and because the total output is well under the expectation. The productivity and citation of Guatemalan science in the 18 journals published in the country, and in other journals also not covered in the in the SCI-expanded, remain unknown. Nevertheless, the historical trend is positive, with a clear growth of international collaboration, productivity and citation.
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Año:
2017
ISSN:
2215-2075, 0034-7744
Parkinson, Randall W.; Cortés, Jorge; Denyer, Percy
Universidad de Costa Rica
Resumen
Geomorphic, sedimentologic. and stratigraphic data obtained from the north Caribbean region of Costa Rica suggests Rio Colorado is a wave-dominated delta whicth has formed along a passive continental margin. This coastal setting is significantly different from tile: south Caribbean and Pacific coastlines, which display geomorphic and lithologic features indicative of seismically active continental margins. The distinct aseismic history and passive margin geomorphology of the north Caribbean coastal plain appears to be controlled by the presence of tectonic features (i.e.,East Nicoya Fracture Zone) which decouple the region from adjacent, tectonically active areas. Although the data collected during this pilot study, including two radiocarbon dates from the base of surficial wetforest and palm swamp sediment. were not sufficient to documentrelative sea-level change, they do confirm the region's aseismic setting. A more complete examination of late Quaternary continental margin stratigraphy will help resolve neotectonic and associated rheological problems, which have remained enigmatic in the absence or a stable datum.
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Año:
2017
ISSN:
2215-2075, 0034-7744
Cruz Salazar, Bárbara; Lorenzo, Consuelo; Espinoza Medinilla, Eduardo; López, Sergio
Universidad de Costa Rica
Resumen
Lepus flavigularis, is an endemic and endangered species, with only four populations inhabiting Oaxaca, México: Montecillo Santa Cruz, Aguachil, San Francisco del Mar Viejo and Santa María del Mar. Nevertheless, human activities like poaching and land use changes, and the low genetic diversity detected with mitochondrial DNA and allozymes in previous studies, have supported the urgent need of management strategies for this species, and suggest the definition of management units. For this, it is necessary to study the genetic structure with nuclear genes, due to their inheritance and high polymorphism, therefore, the objective of this study was to examine the variation and genetic structure of L. flavigularis using nuclear microsatellites. We sampled four populations of L. flavigularis and a total of 67 jackrabbits were captured by night sampling during the period of 2001 to 2006. We obtained the genomic DNA by the phenol-chloroform-isoamyl alcohol method. To obtain the diversity and genetic structure, seven microsatellites were amplified using the Polymerase Chain Reaction (PCR); the amplifications were visualized through electrophoresis with 10 % polyacrylamide gels, dyed with ethidium bromide. Genetic diversity was determined using the software GenAlEx v. 6.4, and genetic structure was obtained with ARLEQUIN v. 3.1; null alleles were evaluated using the program Micro-Checker v.2.2.2. Additionally, a Bayesian analysis was performed with software STRUCTURE v. 2.2.3., and the isolation by distance (IBD) was studied using the program PASSAGE v.2.0.11.6. Our results showed that the genetic variation found was low (HO = 0.30, HE = 0.24) when compared to other jackrabbit species. Fixed alleles and moderate levels of genetic differentiation (FST = 0.18, P = 0.001) were detected among populations, indicating the effect of the genetic drift and limited gene flow. Bayesian clustering analysis revealed two groups: (1) jackrabbits from Montecillo Santa Cruz, and (2) individuals living in Aguachil, San Francisco del Mar Viejo and Santa María del Mar. No evidence was found of isolation by distance. It is possible that the geographic barriers present between populations (e.g. lagoons, human settlements), rather than the geographical distance between them, may explain the observed genetic structure. The inbreeding coefficient was negative (FIS = -0.27, P = 0.03), indicating genetic sub-structure in populations. We suggest two management units based on the genetically closer populations, which will help define precise conservation actions in L. flavigularis. This research is the basis for defining translocation of individuals between populations, nevertheless, a more extensive future study, with specific molecular markers for L. flavigularis, is required. In addition, it is necessary to analyze the barriers that limit the gene flow, since it is urgent to reduce the genetic differentiation between populations and increase the genetic diversity of this species.
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Año:
2017
ISSN:
2215-2075, 0034-7744
Bertolini, Vincenzo; Montaño, Noé Manuel; Chimal Sánchez, Eduardo; Varela Fregoso, Lucía; Gómez Ruiz, Jaime; Martínez Vázquez, José Martín
Universidad de Costa Rica
Resumen
El cultivo del café, en la economía mexicana y en la región del Soconusco en Chiapas, aporta importantes divisas; sin embargo es susceptible a plagas y enfermedades, por lo que se requiere reforzar su producción a través de un manejo más sustentable. Este estudio analizó la abundancia, riqueza y composición de hongos micorrizógenos arbusculares (HMA) nativos que pudieran emplearse en un futuro como biofertilizantes en el cultivo del café. En 21 muestras de suelo recolectadas en noviembre 2015 de siete sitios en la región del Soconusco, Chiapas, México, cultivados con café “robusta” (Coffea canephora), se cuantificó la abundancia de esporas, la riqueza y composición de morfoespecies de HMA y se exploró su relación con las propiedades del suelo. Se obtuvo un total de 20 morfoespecies y cinco nuevos registros de HMA para Chiapas, las morfoespecies más frecuentes pertenecen a los géneros Acaulospora y Glomus. Los sitios Toluca y Victoria tuvieron mayor riqueza de especies (17 spp. c/u) que San Agustín, 20 de noviembre y San Luis Nexapa (4 - 7 spp. c/u); mientras que Providencia y Platanar registraron una riqueza intermedia y los mayores valores de abundancia de esporas. Los sitios Victoria y Toluca presentaron un 97 % de disimilitud en la composición de especies de HMA con respecto a los demás sitios; la cual fue explicada por la baja concentración de PO4-3 en el suelo de Victoria y Toluca. La disponibilidad de P, ligada a la acidez del suelo, fueron los factores que podrían estar regulando las comunidades de HMA en el suelo de la rizosfera de los cafetos en la región del Soconusco. Se propone que podrían haber consorcios de HMA específicos para los niveles de P y acidez presentes en diferentes sitios con cafetos, o bien consorcios de especies de Acaulospora y Glomus que son las condiciones ambientales en las que se desarrolla el café, cuya compatibilidad y funcionalidad debe examinarse antes de emplearlos como biofertilizantes nativos en los cafetos de esta región tropical de México.
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Año:
2017
ISSN:
2215-2075, 0034-7744
Arevalo, Jose Edgardo; Honda, Wataru; Arce-Arias, Adrián; Häger, Achim
Universidad de Costa Rica
Resumen
Roads have detrimental impacts on wildlife populations around the world. Specifically, roads pose direct and indirect threats to wildlife by limiting dispersal movements or through vehicle-related mortality. The rate of wildlife mortality varies both in time and space depending on the landscape composition and the type and use of road infrastructure. The objective of this study was to investigate spatiotemporal variation of vertebrate mortality in a 4km segment of the 34 national road, adjacent to Carara National Park, Costa Rica. We conducted 81 roadkill surveys by car and bicycle from June 2010 to May 2011, georeferenced the locations of the kills and identified them to the lowest possible taxonomic level. We recorded a total of 4 709 road-killed animals of at least 58 species of vertebrates during the whole study. Amphibians accounted for 93.5 % of all the vertebrate losses and showed strong spatiotemporal variation of mass mortality events. Reptiles, especially snakes, were the second most affected taxon followed by mammals and birds. Relative mortality per day in the 4 km segment was 125.4 amphibians, 4.6 reptiles, 2.7 mammals, 1 bird and 0.46 undetermined. Road proximity to the border of the park, traffic volumes and lack of enforcement of speed limits may influence the high rate of roadkills found. We suggest the reinforcement of speed limits, wildlife crossing signage and the retrofitting of the existing culverts as under passes for animals to minimize vertebrate mortality at the road adjacent to Carara National Park.
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Año:
2017
ISSN:
2215-2075, 0034-7744
Montaño-Arias, Susana Adriana; Camargo-Ricalde, Sara Lucía; Grether, Rosaura; Díaz-Pontones, David
Universidad de Costa Rica
Resumen
Mimosa aculeaticarpa var. aculeaticarpa and M. luisana are endemic to Mexico, and are considered as multipurpose plants, due to the diverse services they offer to ecosystems and to local people. Additionally, they are appreciated for their potential to restore tropical environments; hence, the objective of this study was to model the present and potential distribution of these taxa. In 2014, species registers were obtained from two databases (CONABIO and MEXU); each register was taxonomically, geographically and statistically validated. Once validated, the present and potential distribution of M. aculeaticarpa var. aculeaticarpa (based on 99 registers) and M. luisana (based on 50 registers) were obtained using the MAXENT algorithm. For both taxa, the present distribution was overlapped using the layers of: elevation, climate, soil, biogeographic provinces, and hydrologic basins. Mimosa aculeaticarpa var. aculeaticarpa showed a wide distribution in Mexico (16 states); whilst M. luisana was restricted to the states of Puebla and Oaxaca. M. aculeaticarpa var. aculeaticarpa establishes between 1 900 and 2 700 masl, and M. luisana between 500 and 1 760 masl. Both species were established in arid and semiarid climates; however, M. aculeaticarpa var. aculeaticarpa can also be found in temperate and mesic climates. Moreover, both taxa are distributed in calcareous regosol soils; although, M. aculeaticarpa var. aculeaticarpa is also found in eutric regosol, chromic vertisol and haplic phaeozem. The distribution of M. aculeaticarpa var. aculeaticarpa includes eight biogeographic provinces and three hydrologic basins; whilst M. luisana was only located in three provinces and two hydrologic basins; both are present in the Eje Volcánico and Sierra Madre del Sur provinces. The potential distribution models are considered as excellent ones due to an AUC of 0.91 and 0.97, respectively; these models indicated that the temperature and precipitation conditions would be suitable for the enlargement of their distribution. Likewise, these models can be considered an approach to the potential distribution knowlegment of the Mexican mimosas. Nevertheless, it is important to note that the models are static and do not take into account any biotic interaction; therefore, their relationship with reality can vary. Thus, it is recommended to analyze the models through different climate change and land use scenarios.
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Año:
2017
ISSN:
2215-2075, 0034-7744
Dardengo, Juliana de Freitas Encinas; Rossi, Ana Aparecida Bandini; Varella, Tatiane Lemes
Universidad de Costa Rica
Resumen
Native Theobroma species, such as cacauhy, are losing their habitat due to the intense forest fragmentation in the Amazon region, and preserving their genetic diversity has been the main aim of many conservation programs. The aim of the present study is to assess whether fragmentation and habitat reduction affect the genetic structure and lead to genetic diversity losses in natural Theobroma speciosum populations. The study was conducted in two Mato Grosso State (Brazil) locations, namely: Apiacás and Alta Floresta counties. Juruena National Park (JNP) in Apiacás County holds a natural T. speciosum population that has not underwent anthropic influences. A population composed of individuals from three anthropized urban forest parks (UF) in Alta Floresta County was analyzed. The leaves of 75 T. speciosum individuals distributed in the urban forest fragments and of 100 individuals found in the Juruena National Park were sampled. All nine microsatellite loci showed high polymorphism levels between categories (adults and sub-adults), in both populations. The sub-adult individuals of the population (UF) in the fragmented area showed higher value (0.71), whereas the preserved population (JNP) category presented the same value (0.69). The increasing trend of estimating the fixation index towards the fragmented population was observed. The analysis of molecular variance showed 83 % genetic diversity within categories; 16 %, between populations; and only 1 %, between categories. Although the effects were small, a persistent fragmentation process can increase the inbreeding levels and facilitate the genetic drift action. These effects may lead the T. speciosum populations to inbreeding depression, diversity loss and genetic structure change in the course of several generations.
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Año:
2017
ISSN:
2215-2075, 0034-7744
Hernández-Nicolás, Nancy Yazmín; Córdova-Téllez, Leobigildo; Romero-Manzanares, Angélica; Jiménez-Ramírez, Jaime; Luna-Cavazos, Mario
Universidad de Costa Rica
Resumen
Jatropha spp. plants are used in traditional medicine, food and for the elaboration of biofuel. The Tehuacán-Cuicatlán Biosphere Reserve in México holds genetic richness and endemism for this genus, but the specific use of the plants and the seed chemical profiles are still unknown. The objectives of this research were to record the traditional forms of use of Jatropha species, and to analyze the chemical composition of Jatropha spp. seeds. For this, a semi-structured survey was conducted in 15 towns, and 20 interviews were applied in each one between May and August 2012. Data allowed to estimate the Significant Use Level and Relative Use Value per species. Besides, seeds from J. neopauciflora, J. rufescens, and J. rzedowskii were collected between August and October 2013, and to seed flour samples we determined total lipids by the Soxhlet method, crude protein by the Kjendahl method, and ashes according to AOAC methods; fatty acid profile and phorbol esters were determined by gas chromatography and by HPLC, respectively. We recorded that the species J. neopauciflora, J. oaxacana, J. rufescens, J. ciliata, and J. rzedowskii, are used as traditional medicine, food, and ornaments, except for J. ciliata, for which none use was recorded. The Significant Use Level as food was found not significant, but for medicinal purposes, J. neopauciflora obtained the highest Relative Use Value (9.0 %). The latex is used to treat 13 disorders, including dental problems (toothache, sensitivity, caries), oral diseases (oral herpes, gingivitis, and oral candidiasis) with a Significant Use Level of 32.9 %; it is also used as a hemostatic. The protein content among species varied from 23.37 to 26.06 %, and total lipids from 34.79 to 36.60 %. The principal unsaturated fatty acids were oleic (25.08 to 30.09 %) and linoleic (44.55 to 48.46 %), and the saturated fatty acids were palmitic (10.11 to 16.50 %) and stearic (9.47 to 11.15 %). Phorbol esters, the main cause of seed’s toxicity, were absent in J. neopauciflora, J. rufescens, and J. rzedowskii. In conclusion, the Significant Use Level of Jatropha species studied was low, with little cultural acceptance and sporadic utilization. The Relative Use Value was important for medicinal purposes, especially for J. neopauciflora. The dehulled seeds of J. neopauciflora, J. rufescens, and J. rzedowskii are potentially useful as food, having high protein contents, and unsaturated oleic and linoleic fatty acids. With this study we report three non-toxic Jatropha species and recommend to scientifically validate the antimycotic use of J. neopauciflora latex.
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Año:
2017
ISSN:
2215-2075, 0034-7744
Cobián Rojas, Dorka; Schmitter-Soto, Juan J.; Aguilar-Perera, Alfonso; Aguilar Betancourt, Consuelo M.; Ruiz-Zárate, Miguel Á.; González Sansón, Gaspar; Chevalier Monteagudo, Pedro P.; García Rodríguez, Alain; Herrera Pavón, Roberto; Perera Valderrama, Susana; Caballero Aragón, Hansel; de la Guardia, Elena
Universidad de Costa Rica
Resumen
Lionfish (Pterois volitans) invaded the Caribbean region with the potential to alter the composition and structure of native coral reef fish communities. The objective of this study was to analyze the diversity indices of these fish communities potentially affected by lionfish predation and to compare with pre-invasion data. The study was undertaken in two Caribbean marine protected areas (MPAs): Guanahacabibes National Park (PNG) in W Cuba and Xcalak Reefs National Park (PNAX) in S Quintana Roo. We carried out visual censuses of fish species in reef habitats during the dry and rainy seasons of the period 2013-2015. For this, nine sites were defined and evaluated using stationary counts. Our results showed higher species richness (43.47 ± 5.14) and mean abundance (0.76 ± 1.25) in PNG than in PNAX (40.22 ± 4.96, 0.19 ± 0.46, respectively). Diversity decreased after the arrival of lionfish in a single site of PNG and in two sites of the PNAX, but apparently, these results are more related to the fishing activity effect than to the lionfish presence. Based on the results and assuming that changes in the native fish communities by lionfish may not yet be detected, we recommend to continue the monitoring community descriptions in order to detect future changes in native fish communities.
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Año:
2017
ISSN:
2215-2075, 0034-7744
Paaby, Pia; Ramírez, Alonso; Pringle, Cathy M.
Universidad de Costa Rica
Resumen
The benthic macroinvertebrate community of streams draining the south-Caribbean coasl of Costa Rica. was studied to deternine community structure and composition through time (September 1995- May 1996), the effect of vegetation cover on drainage area (forest vs. disturbed sites) and to compare two sampling methods; Surber and kitchen sieve. Five sites, predominantly with a forest cover drainage area, show abundances (mean= 157.60 indivs./m2) and taxa richness (mean><9.65 spp./m2) significantly higher than those found in the disturbed drainage a reas (means--82.08 and 4.62 respectively). All sites have high community heterogeneity indices (> 0.80) which. together with the low similarity indices « 0.40) between sampling times indicate a macroinvenebrate community subject to frequent disturbance eventS that diminish species permanence in the aquatic system. The kitchen sieve sampling method with ten replicates (4 000 em2) is significantly more effective in sampling the community in terms of abundance (mean=165.10) than the traditional Surber sampler (mean=83.03) using three replicates (3 333 cm2). Both are equally effective in the number of taxa collected, although each device captures different tan. The species similarity between the Surber and the sieve method ranges between 0.1379 to 0.7619 when combining all sampling times.
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