Repositorio Digital Ikiam (Univ. Regional Amazónica)
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Monitoring long-term forest dynamics with scarce data: a multi-date classification implementation in the Ecuadorian Amazon
Get PDFMonitoring long-term forest dynamics is essential for assessing human-induced land-cover changes, and related studies are often based on the multi-decadal Landsat archive. However, in areas such as the Tropical Andes, scarce data and the resulting poor signal-to-noise ratio in time series data render the implementation of automated time-series analysis algorithms difficult. The aim of this research was to investigate a novel approach that combines image compositing, multi-sensor data fusion, and postclassification change detection that is applicable in data-scarce regions of the Tropical Andes, exemplified for a case study in Ecuador. We derived biennial deforestation and reforestation patterns for the period from 1992 to 2014, achieving accuracies of 82 ± 3% for deforestation and 71 ± 3% for reforestation mapping. Our research demonstrated that an adapted methodology allowed us to derive the forest dynamics from the Landsat time series, despite the abundant regional data gaps in the archive, namely across the Tropical Andes. This study, therefore, presented a novel methodology in support of monitoring long-term forest dynamics in areas with limited historical data availability
Global, regional, and national age-sex-specific mortality for 282 causes of death in 195 countries and territories, 1980–2017: a systematic analysis for the Global Burden of Disease Study 2017
No full textGlobal development goals increasingly rely on country-specific estimates for benchmarking a nation's progress. To meet this need, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2016 estimated global, regional, national, and, for selected locations, subnational cause-specific mortality beginning in the year 1980. Here we report an update to that study, making use of newly available data and improved methods. GBD 2017 provides a comprehensive assessment of cause-specific mortality for 282 causes in 195 countries and territories from 1980 to 2017. The Lancet Publishing Grou
Making the most of scarce data: Mapping soil gradients in data‐poor areas using species occurrence records
No full textMaps of environmental characteristics are needed to improve our understanding of species distributions and ecosystem dynamics. Despite the growing demand for digital environmental maps, scarcity of environmental field samples to be used as input data often constrains the accuracy of such maps, especially for soils.
We developed and tested a method that combines information on species–environment associations and the spatial distribution of indicator species (as retrieved from repositories such as GBIF) to improve mapping accuracy of environmental variables.
Our approach includes: (a) Compile field data on the environmental variable of interest (direct environmental data) and documented occurrences of the species to be used as indicators; (b) define species optima for the environmental variable; (c) use georeferenced records of the indicator species to calculate species‐based environmental values (indirect environmental data); (d) generate maps using direct and indirect environmental data as input data for interpolation; (e) validate the maps. We applied the method to map the concentration of exchangeable base cations in Amazonian soils using fern and lycophyte species as indicators.
Including soil values that had been indirectly estimated using indicator species represented a 12‐fold increase in the number of input data points used for mapping. At the same time, map accuracy improved considerably: the correlation between mapped soil cation concentration estimates and field‐measured values from an independent validation dataset increased from r = 0.48 to r = 0.71.
Knowledge on species–environment relationships can be useful for modelling ecologically relevant environmental variables in areas where species occurrence data are more readily available than direct environmental measurements. The method works even with haphazard species occurrence points obtained from public repositories such as GBIF and can be applied to other environmental variables and other indicator groups, provided that the environmental variable of interest is relevant as a determinant of species occurrences in the indicator group. The Amazonian soil cation concentration maps produced (available at https://doi.pangaea.de/10.1594/PANGAEA.879542) can be used as digital layers in species distribution and habitat modelling, and to guide conservation actions in Amazonia
Inhibition of DNA methyltransferase leads to increased genomic 5-hydroxymethylcytosine levels in hematopoietic cells
Get PDF5-Hydroxymethylcytosine (5hmC) is produced from 5-methylcytosine
(5mC) by Ten-eleven translocation (TET) dioxygenases. The epigenetic
modification 5hmC has crucial roles in both cellular development and differentiation.
The 5hmC level is particularly high in the brain. While 5mC is
generally associated with gene silencing/reduced expression, 5hmC is a
more permissive epigenetic mark. To understand its physiological function,
an easy and accurate quantification method is required. Here, we have
developed a novel LC-MS/MS-based approach to quantify both genomic
5mC and 5hmC contents. The method is based on the liberation of nucleobases
by formic acid. Applying this method, we characterized the levels of
DNA methylation and hydroxymethylation in mouse brain and liver, primary
hepatocytes, and various cell lines. Using this approach, we confirm
that the treatment of different cell lines with the DNA methyltransferase
inhibitor 5-aza-20-deoxycytidine leads to a decrease in 5mC content. This
decrease was accompanied by an increase in 5hmC levels in cell lines of
hematopoietic origin. Finally, we showed that ascorbate elevates the levels
of 5hmC and augments the effect of 5-aza-20-deoxycytidine without significantly
influencing 5mC levels
Spatial assessment of the potential of renewable energy: The case of Ecuador
Get PDFAlthough renewable energy represents a large share of the electric energy generation sources in Latin America, non-conventional sources such as solar or wind energies have not represented a big share of their electric energy systems. The first step to promote the use of these sources in the region is identifying the potential of each energy source, task that can be estimated with the use of spatial tools such as Geographic Information Systems (GIS). This study has reviewed a large list of GIS publications to select a methodology to identify suitable areas for the development of non-conventional renewable energy projects (REP), in order to estimate the maximum energy these technologies could contribute to a national electric energy system, and its applied to the Republic of Ecuador. By using GIS, it is sought to identify the sites where potential renewable energy plants could be located, and initially recommends geographic locations for the installation of measuring towers of solar and wind resources, in order to obtain more detailed information on their behavior. As a result, the areas with higher potential for the development of REP have been identified, and classified in spatial layers according its technology and location. These results show that solar PV is the technology with most suitable areas in the country and demonstrate particularly large potential in two regions: the Andes cordillera and Insular region, especially in the provinces of Loja, Pichincha and the Galapagos islands
A novel synthetic peptide inspired on Lys49 phospholipase A2 from Crotalus oreganus abyssus snake venom active against multidrug-resistant clinical isolates
No full textCurrently, the evolving and complex mechanisms of bacterial resistance to conventional antibiotics are increasing, while alternative medicines are drying up, which urges the need to discover novel agents able to kill antibiotic-resistant bacteria. Lys49 phospholipase A2s (PLA2s) from snake venoms are multifunctional toxins able to induce a huge variety of therapeutic effects and consequently serve as templates for new drug leads. Hence, the present study was aimed at the synthesis of oligopeptides mimicking regions of the antibacterial Lys49 PLA2 toxin (CoaTx-II), recently isolated from Crotalus oreganus abyssus snake venom, to identify small peptides able to reproduce the therapeutic action of the toxin. Five peptides, representing major regions of interest within CoaTx-II, were synthesized and screened for their antibacterial properties. The 13-mer peptide pC-CoaTxII, corresponding to residues 115–129 of CoaTx-II, was able to reproduce the promising bactericidal effect of the toxin against multi-resistant clinical isolates. Peptide pC-CoaTxII is mainly composed by positively charged and hydrophobic amino acids, a typical trait in most antimicrobial peptides, and presented no defined secondary structure in aqueous environment. The physicochemical properties of pC-CoaTxII are favorable towards a strong interaction with anionic lipid membranes as those in bacteria. Additional in silico studies suggest formation of a water channel across the membrane upon peptide insertion, eventually leading to bacterial cell disruption and death. Overall, our findings confirm the valuable potential of snake venom toxins towards design and synthesis of novel antimicrobials, thus representing key insights towards development of alternative efficient antimicrobials to fight bacterial resistance to current antibiotics
Occurrence of radioactive materials in pyroclastic flows of Tungurahua volcano using gamma spectrometry
Get PDFThe Tungurahua volcano began its last eruptive process in 1999 and has not ceased its activity since then, as a result of this, tons of volcanic material has been deposited on its flanks in each episode of greatest activity. An exploratory study of radioactivity of natural origin has been carried out in the pyroclastic flows near the Palma Urcu ravine (Juive) of the Tungurahua volcano using gamma spectrometry. This pyroclastic material corresponds to the accumulation that occurred after the eruption of August 2006 in an area adjacent to this ravine after its overflow. This material is used in construction. At present, much emphasis is placed on the health risks associated with the radioactivity present in construction materials. In this context, concentrations of activity in several samples of material have been analyzed to determine their risk, finding average values of 27.58 ± 1.99 Bq / kg for Ra-226; 30.28 ± 2.48 Bq / kg for Th-232, and 411 ± 28.77 Bq / kg for K-40. Finding an activity index of 0.38 ± 0.03 It was also calculated the equivalent radio activity, external and internal risk indexes and effective annual equivalent doses found that is bordering the maximum permissible limit recommended by control organisms
One-Pot Peptide Ligation – Oxidative Cyclization Protocol for the Preparation of Short/Medium Size Disulfide Cyclopeptides
Get PDFNative chemical ligation (NCL) employing the
N-methylbenzimidazolinone (MeNbz) linker readily provided
the linear precursor of a 16-mer peptide that is difficult to
obtain by stepwise solid-phase peptide synthesis. NCL and the
workup conditions were improved toward a protocol that
allows for quantitative removal of the 4-hydroxymercapto-
phenol additive and subsequent formation of the disulfide
bridge in the NCL cocktail by oxidation in air, tolerated by the
presence of tris(hydroxypropyl)phosphine
Persistent effects of pre Columbian plant domestication on Amazonian forest composition
No full textThe extent to which pre-Columbian societies altered Amazonian landscapes is hotly debated. We performed a basin-wide analysis of pre-Columbian impacts on Amazonian forests by overlaying known archaeological sites in Amazonia with the distributions and abundances of
85 woody species domesticated by pre-Columbian peoples. Domesticated species are five times more likely to be hyperdominant than non-domesticated species. Across the basin the relative abundance and richness of domesticated species increases in forests on and around archaeological sites. In southwestern and eastern Amazonia distance to archaeological sites strongly influences the relative abundance and richness of domesticated species. Our analyses indicate that modern tree communities in Amazonia are structured to an important extent by a long history of plant domestication by Amazonian peoples.American Association for the Advancement of Scienc
Alimentos Ricos y nutritivos de la Chagra Kichwa
No full textLa diversidad alimentaria contribuye al bienestar
sociocultural, así como para la conservación de la biodiversidad
y de los conocimientos locales asociados a su manejo, uso
factual y uso social de los alimentos . La alimentación es
un aspecto indispensable de la existencia humana. Todas
las sociedades consagran tiempo y atención sustancia la
todas las etapas de alimentarse, desde la obtención hasta el
consumo . Ella reagrupa “las representaciones, los discursos
y las prácticas en relación con la producción, los intercambios
comerciales y no comerciales, la distribución, la preparación
y el consumo de productos alimenticio