Institution
Universidad Simón Rodríguez
Education•Caracas, Venezuela•
About: Universidad Simón Rodríguez is a education organization based out in Caracas, Venezuela. It is known for research contribution in the topics: Trypanosoma vivax & Trypanosoma evansi. The organization has 279 authors who have published 334 publications receiving 4260 citations.
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King Juan Carlos University1, University of Vermont2, Pablo de Olavide University3, Technical University of Madrid4, Northern Arizona University5, University of La Serena6, Instituto Potosino de Investigación Científica y Tecnológica7, Universidad Simón Rodríguez8, Ben-Gurion University of the Negev9, State University of Feira de Santana10, Universidad Técnica Particular de Loja11, University of Sfax12, University of New South Wales13, Central University of Venezuela14, National University of San Juan15, University of the Bío Bío16, Virginia Tech College of Natural Resources and Environment17, Ohio State University18, National Agrarian University19, National University of La Pampa20, University of New England (Australia)21, Office of Environment and Heritage22, Spanish National Research Council23, Northeast Normal University24, Agricultural Research Organization, Volcani Center25
TL;DR: A global empirical study relating plant species richness and abiotic factors to multifunctionality in drylands, which collectively cover 41% of Earth’s land surface and support over 38% of the human population, suggests that the preservation of plant biodiversity is crucial to buffer negative effects of climate change and desertification in dryland.
Abstract: Experiments suggest that biodiversity enhances the ability of ecosystems to maintain multiple functions, such as carbon storage, productivity, and the buildup of nutrient pools (multifunctionality). However, the relationship between biodiversity and multifunctionality has never been assessed globally in natural ecosystems. We report here on a global empirical study relating plant species richness and abiotic factors to multifunctionality in drylands, which collectively cover 41% of Earth’s land surface and support over 38% of the human population. Multifunctionality was positively and significantly related to species richness. The best-fitting models accounted for over 55% of the variation in multifunctionality and always included species richness as a predictor variable. Our results suggest that the preservation of plant biodiversity is crucial to buffer negative effects of climate change and desertification in drylands.
941 citations
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TL;DR: In this article, the role of organic matter in sustaining the fertility of soils from three different climate zones was quantified, and it was shown that without supplementary fertilization was economical for 65 years on temperate prairie and for six years in a tropical semiarid thorn forest.
Abstract: MANY tropical soils are poor in inorganic nutrients and rely on the recycling of nutrients from soil organic matter to maintain fertility. In undisturbed rainforests such nutrients are recycled via the litter1; 'slash-and-burn' agriculture, meanwhile, depends on the mineralization of organic nutrients from the plant remains2,3 or on (short-lived) inputs from ash4. This dependence on organic nutrients in tropical soils has the result that tests of soil quality which only give isolated measures of inorganic nutrient status are unreliable5, and that the effects of fertilization can be inconsistent because of leaching or fixation of inorganic nutrients. Here we attempt to quantify the role of organic matter in sustaining the fertility of soils from three different climate zones. We estimate rates of carbon turnover from ecological measurements and 14C dating, and determine its relation to the soil carbon and nutrient budgets. We find that agriculture without supplementary fertilization was economical for 65 years on temperate prairie and for six years in a tropical semi-arid thorn forest. An extremely nutrient-poor Amazonian soil showed no potential for agriculture beyond the three-year lifespan of the forest litter mat, once biological nutrient cycles were interrupted by slash-burning. These observations suggest that quantification of organic-matter cycling may provide an important guide to the agricultural potential of soils.
785 citations
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TL;DR: It is hypothesized that the high availability of homopteran honeydew provides a key resource for ant mosaics, where dominant ant colonies and species maintain mutually exclusive territories on trees.
Abstract: Ant-plant interactions in the canopy of a lowland Amazonian rainforest of the upper Orinoco, Venezuela, were studied using a modified commercial crane on rails (Surumoni project). Our observations show a strong correlation between plant sap exudates and both abundance of ants and co-occurrence of ant species in tree canopies. Two types of plant sap sources were compared: extrafloral nectaries (EFNs) and honeydew secretions by homopterans. EFNs were a frequent food source for ants on epiphytes (Philodendron spp., Araceae) and lianas (Dioclea, Fabaceae), but rare on canopy trees in the study area, whereas the majority of trees were host to aggregations of homopterans tended by honeydew-seeking ants (on 62% of the trees examined). These aggregations rarely occurred on epiphytes. Baited ant traps were installed on plants with EFNs and in the crowns of trees from three common genera, including trees with and without ant-tended homopterans: Goupia glabra (Celastraceae), Vochysia spp. (Vochysiaceae), and Xylopia spp. (Annonaceae). The number of ant workers per trap was significantly higher on plants offering one of the two plant sap sources than on trees without such resources. Extrafloral nectaries were used by a much broader spectrum of ant species and genera than honeydew, and co-occurrence of ant species (in traps) was significantly higher on plants bearing EFNs than on trees. Homopteran honeydew (Coccidae and Membracidae), on the other hand, was mostly monopolised by a single ant colony per tree. Homopteran-tending ants were generally among the most dominant ants in the canopy. The most prominent genera were Azteca, Dolichoderus (both Dolichoderinae), Cephalotes, Pheidole, Crematogaster (all Myrmicinae), and Ectatomma (Ponerinae). Potential preferences were recorded between ant and homopteran species, and also between ant-homopteran associations and tree genera. We hypothesize that the high availability of homopteran honeydew provides a key resource for ant mosaics, where dominant ant colonies and species maintain mutually exclusive territories on trees. In turn, we propose that for nourishment of numerous ants of lower competitive capacity, Philodendron and other sources of EFNs might be particularly important.
279 citations
01 Jan 2003
163 citations
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TL;DR: The ability of an environmentally friendly extraction technique such as Pressurized Liquid Extraction and a traditional extraction technique to obtain functional compounds from C. vulgaris at analytical scale has been demonstrated.
Abstract: Chlorella vulgaris has been referred as a potential source of bioactive compounds (carotenoids and fatty acids). In this work, the ability of an environmentally friendly extraction technique such as Pressurized Liquid Extraction (PLE) and a traditional extraction technique such as Ultrasound-Assisted Extraction (UAE) to obtain functional compounds from C. vulgaris, at analytical scale, has been demonstrated. Seeked bioactivities were antioxidant and antimicrobial, for their interest in the food industry. Therefore, a methodology including analytical extraction, in-vitro assays and chemical characterization via HPLC-DAD and GC–MS has been used to determine the interest of Chlorella as a source of functional food ingredients. Results demonstrated that PLE provide higher yields than UAE while similar bioactivities were obtained. Important concentration of carotenoids (lutein, neoxanthin, β-carotene, etc.), chlorophylls, sterols, phytols, and fatty acids (among others) have been found in Chlorella extracts that could be correlated to the observed biological activity.
108 citations
Authors
Showing all 283 results
Name | H-index | Papers | Citations |
---|---|---|---|
Guillermo Reglero | 50 | 301 | 9312 |
Gerardo Rodríguez | 36 | 177 | 4417 |
Reinaldo DiPolo | 31 | 75 | 2866 |
Neil R. Lynch | 27 | 48 | 2227 |
Gustavo Benaim | 27 | 75 | 1881 |
José Bubis | 23 | 80 | 1489 |
Danilo López-Hernández | 22 | 57 | 1388 |
Héctor Rojas | 17 | 65 | 724 |
Alfredo Mijares | 13 | 55 | 599 |
M. Mendoza | 11 | 15 | 328 |
Trina Perrone | 11 | 22 | 326 |
Maria E. Rodriguez | 10 | 34 | 258 |
Graciela L. Uzcanga | 10 | 23 | 359 |
Hugo Cerda | 9 | 16 | 230 |
Claudia Colina | 9 | 11 | 422 |