Repositorio Digital Ikiam (Univ. Regional Amazónica)
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100 years of human adaptation to climate change in the High Andes
Get PDFumid montane forests are challenging environments for human habitation. We used high-resolution fossil pollen, charcoal, diatom and sediment chemistry data from the iconic archaeological setting of Laguna de los Condores, Peru to reconstruct changing land uses and climates in a forested Andean valley. Forest clearance and maize cultivation were initiated during peri-ods of drought, with periods of forest recovery occurring during wetter conditions. Between ad 800 and 1000 forest regrowth was evident, but this trend was reversed between ad 1000 and 1200 as drier conditions coincided with renewed land clear-ance, the establishment of a permanent village and the use of cliffs overlooking the lake as a burial site. By ad 1230 forests had regrown in the valley and maize cultivation was greatly reduced. An elevational transect investigating regional patterns showed a parallel, but earlier, history of reduced maize cultivation and forest regeneration at mid-elevation. However, a lowland site showed continuous maize agriculture until European conquest but very little subsequent change in forest cover. Divergent, climate-sensitive landscape histories do not support categorical assessments that forest regrowth and peak carbon sequestra-tion coincided with European arriva
Wing geometric morphometrics as a tool for taxonomic identification of two fly species (Diptera: Muscidae) of forensic relevance
Get PDFThe taxonomic identification of fly species through wing geometry is a helpful tool for entomologists and officials involved in forensic research, who not necessarily require expertise on insect taxonomy. Members of the Muscidae family are relevant sources of evidence in forensic entomology; however, developing countries often lack experts in the taxonomical identification of essential species for the assessment of aspects such as the minimum postmortem interval (mPMI). Our study proposes a low-cost, fast, and technologically-accessible quantitative tool for the identification of Atherigona orientalis and Ophyra aenescens, associated with human corpses at advanced states of decomposition. We propose a tool that is based on the geometric variability observed in eight homologous landmarks on wing veins and the interpretation of morphometric estimates after a generalized Procrustes analysis. The use of a geometric approach for effective discrimination between Atherigona orientalis and Ophyra aenescens was supported by statistically significant differences in wing conformation and size. The evidence presented in this study shows that the analysis of geometric variability in the wing morphology of species of forensic relevance can contribute to simple and objective species identification. Geometric morphometrics is a simple and readily available tool for forensic science
Rarity of monodominance in hyperdiverse Amazonian forests
Get PDFTropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors
Techno-Economic Study of a Biogas-Based Polygeneration Plant for Small Dairy Farms in Central Bolivia
Get PDFThis paper presents a techno-economic feasibility study of a polygeneration plant proposed for an association of dairy farmers in Bolivia. The systems have been designed in an integrated approach and are based on the resource recovery utilizing available cow dung. The production of biogas is proposed using “low cost” tubular digesters. The biogas is used for the production of electricity and heat in a 40 kWel internal combustion engine. Heat from the exhaust gas is recovered to drive an absorption cooling system for milk refrigeration and for a bio-slurry drying system. The final services are biogas, electricity, cooling and fertilizers. The techno-economic analysis focuses on determining the levelized cost of the services and compare them with the subsidized and non-subsidized prices of other competitive services in the market. Sensitivity analyses for the services prices are carried out to see the influence of the feedstock handling cost and the subsidies on investment capital. Once the selling prices of the services are defined, the payback period of investment capital is determined. The results show that the biogas and electricity costs were found lower than the subsidized prices of similar services in the market while the cost of cooling was found slightly higher. From the sensitivity analysis we have that the feedstock handling cost can be increased from 10 to 18 USD/ton while maintaining the biogas price below the subsidized LPG price, and applying subsidies to the investment capital allows reducing the rest of the services costs. The payback period is around 3.5 years when a subsidy of 15% is applied in the investment capital and the services are sold at the subsidized prices of the conventional services. Our study has shown that under the conditions of the Bolivian market it is feasible the installation of a polygeneration plant. On the other hand, a market without or with reduced subsidies for the conventional services makes the proposed system more feasible and competitive
Identification of oxidosqualene cyclases from the medicinal legume tree Bauhinia forficata: a step toward discovering preponderant α-amyrin-producing activity
Get PDFTriterpenoids are widely distributed among plants of the legume family. However, most studies have focused on triterpenoids and their biosynthetic enzymes in model legumes. We evaluated the triterpenoid aglycones profile of the medicinal legume tree Bauhinia forficata by gas chromatography-mass spectrometry. Through transcriptome analyses, homology-based cloning, and heterologous expression, we discovered four oxidosqualene cyclases (OSCs) which are responsible for the diversity of triterpenols in B. forficata. We also investigated the effects of the unique motif TLCYCR on α-amyrin synthase activity. B. forficata highly accumulated α-amyrin. We discovered an OSC with a preponderant α-amyrin-producing activity, which accounted for at least 95% of the total triterpenols. We also discovered three other functional OSCs (BfOSC1, BfOSC2, and BfOSC4) that produce β-amyrin, germanicol, and cycloartenol. Furthermore, by replacing the unique motif TLCYCR from BfOSC3 with the MWCYCR motif, we altered the function of BfOSC3 such that it no longer produced α-amyrin. Our results provide new insights into OSC cyclization, which is responsible for the diversity of triterpenoid metabolites in B. forficata, a non-model legume plant
Celebrating Alexander von Humboldt’s 250 th anniversary: Exploring bio- and geodiversity in the Andes (IBS Quito 2019)
Get PDFAlexander von Humboldt conducted his best‑known work on the slopes of the Ecuadorian Andes. He did this by applying his own characteristic brand of multidisciplinary scientific approach. This consisted of thorough data collection while synthesizing and visualizing the data in innovative formats. Also important for his scientific success in South America was his collaborative network that helped him to identify specimens and formulate his transformative scientific thoughts. It is no surprise that Humboldt was captivated by Ecuador, as it is one of the most biodiverse places in the world, and this astounding diversity was formed in an intricate, dynamic geological and climatological setting. As of yet, this biodiversity is far from being fully documented and the processes that generated it are still poorly understood. The IBS meeting in Quito1 and the Second Latin American Congress of Biogeography will form the perfect platform to both commemorate Humboldt while addressing current and unresolved matters concerning the biodiversity of Ecuador and South America at large
Women´s Empowerment in Ecuador: Differentiating the impact of two interventions
Get PDFThis paper analyses the impact of two interventions on women's empowerment in Ecuador using an experimental design. Women's empowerment is operationalized by using two metrics: first, the participation of women in the decision process at household level and, second, the disagreements between men and women in the decision process. We find negative effects of both interventions on women's participation on the decision‐making process at household level. However, we do find positive effects on disagreements regarding women's work and use of contraceptives, as well as positive effects of vouchers on disagreements on large food purchases and large assets purchasesJohn Wiley & Sons Inc
Francisco Campos-Rivadeneira and Roberto Levi- Castillo: Their lives and contributions to the study of mosquitoes (Diptera: Culicidae) in Ecuador
No full textThe study of mosquitoes is important in the prevention of vector-borne diseases. In Ecuador, the study of local mosquito biodiversity was pioneered by two entomologists whose contributions span through the first half of the 20th century, Francisco Campos- Rivadeneira and Roberto Levi-Castillo. Both of them contributed to general aspects of Entomology and to particular insights in mosquito taxonomy. Their publications and discoveries were recognized by the international scientific community but went unnoticed in South America during their time. Today, very few citizens remember the names and contributions of these two scientists. Here, we provide an overview of their lives, a summary of their contributions, and we conclude with a broader outlook on the practice of science in Latin America during their time.Biomédic
White sand vegetation in an Amazonian lowland under the perspective of a young geological history
Get PDFWhat controls the formation of patchy substrates of white sand vegetation in the Amazonian lowlands is still unclear. This research integrated the geological history and plant inventories of a white sand vegetation patch confined to one large fan-shaped sandy substrate of northern Amazonia, which is related to a megafan environment. We examined floristic patterns to determine whether abundant species are more often generalists than the rarer one, by comparing the megafan environments and older basement rocks. We also investigated the pattern of species accumulation as a function of increasing sampling effort. All plant groups recorded a high proportion of generalist species on the megafan sediments compared to older basement rocks. The vegetation structure is controlled by topographic gradients resulting from the smooth slope of the megafan morphology and microreliefs imposed by various megafan subenvironments. Late Pleistocene-Holocene environmental disturbances caused by megafan sedimentary processes controlled the distribution of white sand vegetation over a large area of the Amazonian lowlands, and may have also been an important factor in species diversification during this period. The integration of geological and biological data may shed new light on the existence of many patches of white sand vegetation from the plains of northern Amazonia
Molecular modeling of four Dermaseptin-related peptides of the gliding tree frog Agalychnis spurrelli
Get PDFIn this research, we present a preliminary computational study of four Dermaseptin-related peptides from the skin exudate of thegliding tree frogAgalychnis spurrelli. Experimentally, the amino acid sequence of these peptides was elucidated throughmolecular cloning and tandem mass spectrometry and synthetic peptides were assayed againstE. coli,S. aureus,andC. albicansto determine their antimicrobial properties. With the sequences on hand, a computational study of the structureswas carried out, obtaining their physicochemical properties, secondary structure, and their similarity to other known peptides. Amolecular docking study of these peptides was also performed against cell membrane and several enzymes are known to be vitalfor the organisms. Results showed that Dermaseptin-related peptides areα-helical cationic peptides with an isoelectric pointabove 9.70 and a positive charge of physiological pH. Introducing theses peptides in a database, it was determined that theiridentity compared with known peptides range from 36 to 82% meaning these four Dermaseptins are novel peptides. Thispreliminary study of molecular docking suggests the mechanism of action of this peptide is not given by the inhibition ofessential enzymatic pathways, but by cell lysis