Repositorio Digital Ikiam (Univ. Regional Amazónica)
Not a member yet
850 research outputs found
Sort by
Management and design of biogas digesters: A non-calibrated heat transfer model
Get PDFA thermal balance modeling framework is developed, based on heat transfer-resistance networks. The heat transfer model accounts for effects of digester- design, location and operation, including effects of solar irradiance, external heating and ambient climate. We demonstrate extendibility of the framework by using the model in dynamic simulations of substrate temperature for digesters comprising two very different designs. Digester designs modeled include fixed-dome, buried, uninsulated and unheated household digesters in Hanoi, Vietnam, and an industrial-scale anaerobic digester located at a wastewater treatment plant in Esbjerg, Denmark. The modeled temperature profiles were evaluated against measured substrate temperatures over long periods, from 7 months and up. For the two Hanoi digesters, root-mean-square-error were 1.43 °C and 0.92 °C, with Nash-Sutcliffe model efficiency coefficients (NS-C) of 0.87 and 0.93 respectively. For the industrial digester in Esbjerg root-mean-square-error was 0.48 °C with an NS-C of 0.94. The model was not calibrated prior simulation, suggesting good predictive performance
NEOTROPICAL CARNIVORES: a data set on carnivore distribution in the Neotropics
Get PDFAbstract.Mammalian carnivores are considered a key group in maintaining ecologicalhealth and can indicate potential ecological integrity in landscapes where they occur. Carni-vores also hold high conservation value and their habitat requirements can guide managementand conservation plans. The order Carnivora has 84 species from 8 families in the Neotropicalregion: Canidae; Felidae; Mephitidae; Mustelidae; Otariidae; Phocidae; Procyonidae; andUrsidae. Herein, we include published and unpublished data on native terrestrial Neotropicalcarnivores (Canidae; Felidae; Mephitidae; Mustelidae; Procyonidae; and Ursidae). NEOTRO-PICAL CARNIVORES is a publicly available data set that includes 99,605 data entries from35,511 unique georeferenced coordinates. Detection/non-detection and quantitative data wereobtained from 1818 to 2018 by researchers, governmental agencies, non-governmental organi-zations, and private consultants. Data were collected using several methods including cameratrapping, museum collections, roadkill, line transect, and opportunistic records. Literature(peer-reviewed and grey literature) from Portuguese, Spanish and English were incorporated inthis compilation. Most of the data set consists of detection data entries (n=79,343; 79.7%) butalso includes non-detection data (n=20,262; 20.3%). Of those, 43.3% also include count data(n=43,151). The information available in NEOTROPICAL CARNIVORES will contribute tomacroecological, ecological, and conservation questions in multiple spatio-temporal perspec-tives. As carnivores play key roles in trophic interactions, a better understanding of their distri-bution and habitat requirements are essential to establish conservation management plans andsafeguard the future ecological health of Neotropical ecosystems. Our data paper, combinedwith other large-scale data sets, has great potential to clarify species distribution and relatedecological processes within the Neotropics. There are no copyright restrictions and no restric-tion for using data from this data paper, as long as the data paper is cited as the source of theinformation used. We also request that users inform us of how they intend to use the data
A checklist of Diptera collected in the Caña de Azúcar morgue of Aragua, Venezuela
Get PDFBackground: Venezuela has experienced soaring rates of violent crime, in particular, homicides. The Aragua state
with 142 to 168 crimes per 100,000 inhabitants has the highest homicide rate in the last 5 years. All these cases are
transferred to the estate morgue. Entomological evidence on cadavers has been used as a tool to clarify the death
causes. Due to this, we analyzed the occurrence of forensically important dipteran species on facilities of the Caña
de Azúcar morgue in Aragua, Venezuela.
Findings: A total of 692 adult insects belonging to five species of Calliphoridae and Muscidae were collected at the
Caña de Azúcar morgue premises (body holding area and autopsy room). Chrysomya megacephala and Musca
domestica were the most frequent species in the morgue areas. Other species with forensic importance were also
found: Lucilia cuprina, Chrysomya albiceps, and Ophyra aenescens
FSplines: A Software for Linear Stability Analysis of Thin-Walled Structures, Version 2.0
Get PDFFSplines is a (geometrically) linear stability analysis tool of thin-walled structures with open section (useful for cold-formed steel profiles), that enables obtaining the bifurcation stresses (critical stress, load and moment) and the respective buckling modes by the Finite Strip Method (FSM).
The Finite Strip Method: (i) allows analyzing prismatic steel members (commercial structural profiles), (ii) is an alternative to the Finite Element Method (FEM), and (iii) has some important advantages over FEM. In the present article, two variants of the FSM are presented: (i) the Semi-Analytical Finite Strip Method (SAFSM), where use is made of trigonometric functions and (ii) the Splines Finite Strip Method (SFSM), employing spline functions. The SAFSM has the advantage of being less time consuming. Its main restriction is the fact that it only allows modelling simple supported members (pinned restrained). The SFSM most important advantage is the ability to model members with all kinds of boundary conditions. This method is, however, more time consuming.
It is worth noting that the bifurcation analysis, performed by the computer application FSplines, is required for the design of cold formed members according to the specifications of international standards.
FSplines 2.0 is the second version of the computer application here presented. In this second improved version more cross-sections are available, and more section properties are presented
Biased-corrected richness estimates for the Amazonian tree flora
Get PDFAmazonian forests are extraordinarily diverse, but the estimated species richness is very much debated. Here, we apply an ensemble of parametric estimators and a novel technique that includes conspecific spatial aggregation to an extended database of forest plots with up-to-date taxonomy. We show that the species abundance distribution of Amazonia is best approximated by a logseries with aggregated individuals, where aggregation increases with rarity. By averaging several methods to estimate total richness, we confirm that over 15,000 tree species are expected to occur in Amazonia. We also show that using ten times the number of plots would result in an increase to just ~50% of those 15,000 estimated species. To get a more complete sample of all tree species, rigorous field campaigns may be needed but the number of trees in Amazonia will remain an estimate for years to come
Evolutionary diversity is associated with wood productivity in Amazonian forests
Get PDFHigher levels of taxonomic and evolutionary diversity are expected to maximize ecosystem function, yet their relative importance in driving variation in ecosystem function at large scales in diverse forests is unknown. Using 90 inventory plots across intact, lowland, terra firme, Amazonian forests and a new phylogeny including 526 angiosperm genera, we investigated the association between taxonomic and evolutionary metrics of diversity and two key measures of ecosystem function: aboveground wood productivity and biomass storage. While taxonomic and phylogenetic diversity were not important predictors of variation in biomass, both emerged as independent predictors of wood productivity. Amazon forests that contain greater evolutionary diversity and a higher proportion of rare species have higher productivity. While climatic and edaphic variables are together the strongest predictors of productivity, our results show that the evolutionary diversity of tree species in diverse forest stands also influences productivity. As our models accounted for wood density and tree size, they also suggest that additional, unstudied, evolutionarily correlated traits have significant effects on ecosystem function in tropical forests. Overall, our pan-Amazonian analysis shows that greater phylogenetic diversity translates into higher levels of ecosystem function: tropical forest communities with more distantly related taxa have greater wood productivity
Unravelling the Skin Secretion Peptides of the Gliding Leaf Frog, Agalychnis spurrelli (Hylidae)
Get PDFFrog skin secretions contain medically-valuable molecules, which are useful for the discovery of new biopharmaceuticals. The peptide profile of the skin secretion of Agalychnis spurrelli has not been investigated; therefore, the structural and biological characterization of its compounds signify an inestimable opportunity to acquire new biologically-active chemical scaffolds. In this work, skin secretion from this amphibian was analysed by molecular cloning and tandem mass spectrometry. Although the extent of this work was not exhaustive, eleven skin secretion peptides belonging to five peptide families were identified. Among these, we report the occurrence of two phyllokinins, and one medusin-SP which were previously reported in other related species. In addition, eight novel peptides were identified, including four dermaseptins, DRS-SP2 to DRS-SP5, one phylloseptin-SP1, and three orphan peptides. Phylloseptin-SP1 and dermaseptins-SP2 were identified in HPLC fractions based on their molecular masses determined by MALDI-TOF MS. Among the antimicrobial peptides, dermaseptin-SP2 was the most potent, inhibiting Escherichia coli, Staphylococcus aureus, and ORSA with a minimum inhibitory concentration (MIC) of 2.68 μM, and Candida albicans with an MIC of 10.71 μM, without haemolytic effects. The peptides described in this study represent but a superficial glance at the considerable structural diversity of bioactive peptides produced in the skin secretion of A. spurrell
Performance Analysis of a Small-Scale Biogas-Based Trigeneration Plant: An Absorption Refrigeration System Integrated to an Externally Fired Microturbine
Get PDFTrigeneration or combined cooling, heat and power (CCHP) systems fueled by raw biogas
can be an interesting alternative for supplying electricity and thermal services in remote rural areas
where biogas can be produced without requiring sophisticated equipment. In this sense, this study
considers a performance analysis of a novel small-scale CCHP system where a biogas-fired, 5 kW
el
externally fired microturbine (EFMT), an absorption refrigeration system (ARS) and heat exchangers
are integrated for supplying electricity, refrigeration and hot water demanded by Bolivian small dairy
farms. The CCHP solution presents two cases, current and nominal states, in which experimental and
design data of the EFMT performance were considered, respectively. The primary energy
/
exergy rate
was used as a performance indicator. The proposed cases show better energy performances than those
of reference fossil fuel-based energy solutions (where energy services are produced separately) allowing
savings in primary energy utilization of up to 31%. Furthermore, improvements in electric efficiency of
the EFMT and coefficient of performance (COP) of the ARS, identified as key variables of the system,
allow primary energy savings of up to 37%. However, to achieve these values in real conditions, more
research and development of the technologies involved is required, especially for the EFMT.
(15) (PDF) Performance Analysis of a Small-Scale Biogas-Based Trigeneration Plant: An Absorption Refrigeration System Integrated to an Externally Fired Microturbine. Available from: https://www.researchgate.net/publication/336398032_Performance_Analysis_of_a_Small-Scale_Biogas-Based_Trigeneration_Plant_An_Absorption_Refrigeration_System_Integrated_to_an_Externally_Fired_Microturbine [accessed Nov 27 2019]
Evaluating elastic wave velocities in Brazilian municipal solid waste
Get PDFThe sanitary landfills in Brazil are, generally, characterized by their high organic material content (around 60%), presence of different types of mixed wastes, and low compaction energy, which differentiates them from the landfills of developed and high-income countries. To prevent environmental and slope stability risks, it is crucial to understand the behavior of such landfills and the changes in their physical properties over time. The compression wave velocity (Vp) and shear wave velocity (Vs) are important parameters to subsidize the mechanical characterization of sanitary landfills, using which can be derived the dynamic elastic properties of municipal solid waste (MSW) for stability analysis. Using the geophysical methods of seismic refraction, active and passive multichannel analysis of surface waves, and crosshole test, it was obtained the values of Vp and Vs by employing an experimental cell and a lysimeter filled with MSW in the City of Campinas, São Paulo State, Brazil. The results obtained from the crosshole test showed that Vp ranged from 217 to 252 m/s and Vs ranged from 86 to 89 m/s. These low values can be attributed to the high content of organic material, low compaction energy, and climatic conditions such as high pluviometry index and high temperatures that together lead to changes in the pore fluid saturation, effective stress, and pore pressure. These values are indicative of the lower limit of the corresponding velocities reported in most literature; however, they are in accordance with the values reported for landfills located in countries with similar socioeconomic and climatic conditions
Molecular Basis of C-30 Product Regioselectivity of Legume Oxidases Involved in High-Value Triterpenoid Biosynthesis
Get PDFThe triterpenes are structurally diverse group of specialized metabolites with important
roles in plant defense and human health. Glycyrrhizin, with a carboxyl group at C-30
of its aglycone moiety, is a valuable triterpene glycoside, the production of which is
restricted to legume medicinal plants belonging to the Glycyrrhiza species. Cytochrome
P450 monooxygenases (P450s) are important for generating triterpene chemodiversity
by catalyzing site-specific oxidation of the triterpene scaffold. CYP72A154 was previously
identified from the glycyrrhizin-producing plant Glycyrrhiza uralensis as a C-30 oxidase in
glycyrrhizin biosynthesis, but its regioselectivity is rather low. In contrast, CYP72A63 from
Medicago truncatula showed superior regioselectivity in C-30 oxidation, improving the
production of glycyrrhizin aglycone in engineered yeast. The underlying molecular basis
of C-30 product regioselectivity is not well understood. Here, we identified two amino acid
residues that control C-30 product regioselectivity and contribute to the chemodiversity
of triterpenes accumulated in legumes. Amino acid sequence comparison combined with
structural analysis of the protein model identified Leu149 and Leu398 as important amino
acid residues for C-30 product regioselectivity. These results were further confirmed by
mutagenesis of CYP72A154 homologs from glycyrrhizin-producing species, functional
phylogenomics analyses, and comparison of corresponding residues of C-30 oxidase
homologs in other legumes. These findings could be combined with metabolic engineering
to further enhance the production of high-value triterpene compounds