Repositorio Digital Ikiam (Univ. Regional Amazónica)
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Synthesis of Novel Catalytic Materials: Titania Nanotubes and Transition Metal Carbides, Nitrides, and Sulfides
Get PDFThe synthesis and catalytic application of novel catalytic materials such as inorganic nanotubes and transition metal carbides and nitrides have been discussed in this chapter. The overall forecast for new catalytic materials, their methods of synthesis to design innovative materials, as well as the comparison with physical or chemical traditional methods have been emphasized. Specifically, the general aspects concerning the titanate nanotubes, including their routes of preparation and their characterizations for the production of valuable chemical intermediates, are discussed. The catalytic application of these solids as catalysts or supported catalysts for polymerization, photocatalytic activity, anodization, Knoevenagel reaction, oxidation and reduction of methyl orange, Cannizzaro reaction, CO oxidation, hydroformylation of vinyl acetate, and phenol oxidation reactions has been discussed. In addition to these advances, the catalytic profile of transition metal carbides and nitrides as novel catalysts for hydrotreatment reactions is described, making emphasis in bulk and supported material characteristics. Finally, this chapter reviews some studies with model molecules and real feedstocks, mechanism of hydrogen activation and transfer, and relationships between their resistance to severe deactivation and high activity with their resemblance with noble metals
Primer registro de depredación de un gecko por un parúlido ( Setophaga petechia aurea ) en las Islas Galápagos
Get PDFEsta subespecie ha sido descrita como una variante morfológica con relacióna las formas continentales, mostrando un mayortamaño del culmen (largo y ancho) y masa corporal[5], como se ha registrado en otros paserinos de islas. este es el primer registro de depredación de unvertebrado por parte de un parúlido, específicamente deS. p. aurea. Consideramos importante el registro dedepredación debido al tamaño de la presa, así como dela conducta atípica de depredación de esta ave sobreotro vertebrado
Microscopic and molecular evaluation of Strongyloides venezuelensis in an experimental life cycle using Wistar rats
Get PDFStrongyloides venezuelensis is a nematode whose natural host is
rats. It is used as a model for the investigation of human strongyloidiasis caused by
S. stercoralis. The latter is a Neglected Tropical Disease that affects Ecuador,
where there are no specific plans to mitigate this parasitic illness
Estructura y diversidad funcional de la comunidad de quirópteros en sitios piemontanos con diferente tipo de uso del suelo
Get PDFThe Chiroptera order has a lot of species richness and a great variety of eating habits,
highlighting them as important providers of ecosystem functions. Land use change is one of
the factors that most affects the composition of bat communities. The piedmont forest is
one of the ecosystems with the greatest potential bat richness and also one of the most
threatened; it is made up of different land uses. In order to understand the structure and
functional diversity of the bat community, piedmont chagras and forests were sampled in
the buffer zone of the Colonso Chalupas Biological Reserve. Using mist nets, 224 bats of 33
species of the family Phyllostomidae were captured during 23 nights and 8280 h-m; 14 were
restricted to forest, 4 to chagra and 15 were captured in both. The forests have a higher
diversity (Shannon-Wiener 2.87 > 2.12). There more animalivorous and frugivorous species
in the forest than in the chagra, and there were sensitive species such as Chrotopterus
auritus that showed the good state of recovery of the forest, which is essential to include in
conservation programs. A lower proportion of pregnant and lactating juveniles and females
were found in chagra than in the forest, possibly to avoid predation. It was observed that
the chagras conserve only 50% of the species in the forest, so it is important to enrich and
improve them for bat conservation and to conduct more studies in other land uses and
other sites within the reserve
Psychrophilic Full Scale Tubular Digester Operating over Eight Years: Complete Performance Evaluation and Microbiological Population
Get PDFMost biogas plants in the world run under psychrophilic conditions and are operatedby small and medium farmers. There is a gap of knowledge on the performance of these systemsafter several years of operation. The aim of this research is to provide a complete evaluation of apsychrophilic, low-cost, tubular digester operated for eight years. The thermal performance wasmonitored for 50 days, and parameters such as pH, total volatile fatty acid (tVFA), chemical oxygendemand (COD) and volatile solids (VS) were measured every week for the influent and effluent.The digester operated at a stabilized slurry temperature of around 17.7◦C, with a mean organic loadrate (OLR) equal to 0.52 kg VS/m3digester*d and an estimated hydraulic retention time (HRT) of25 days. The VS reduction in the digester was around 77.58% and the COD reduction was 67±3%,with a mean value for the effluent of 3.31±1.20 g COD/Lt, while the tVFA decreased by 83.6±15.5%and the presence of coliforms decreased 10.5%. A BioMethane potential test (BMP) for the influentand effluent showed that the digester reached a specific methane production of 0.40 Nm3CH4/kgVS and a 0.21 Nm3CH4/m3digesterd with 63.1% CH4in the biogas. These results, together witha microbiological analysis, show stabilized anaerobic digestion and a biogas production that washigher than expected for the psychrophilic range and the short HRT; this may have been due to thepresence of an anaerobic digestion microorganism consortium which was extremely well-adapted topsychrophilic conditions over the eight-year study period
Selective catalytic reduction of nitrogen oxide by ammonia over Cu/SAPO-11: a theoretical study
Get PDFQuantum chemistry calculations were carried out using the ONIOM2 methodology at two diferent levels of calculation,B3LYP for the high level and UFF for the low level. These calculations were performed on Cu/SAPO-11, NO–Cu/SAPO-11,NH3–Cu/SAPO-11 and NO+NH3–Cu/SAPO-11 to investigate the reaction pathway of the selective catalytic reduction of nitrogen oxides by ammonia in the presence of Cu/SAPO-11. NH2NO is formed, and then is decomposed into N2 and H2O
over Cu/SAPO-11 for the catalytic reduction of NO in two steps. The adsorption energy ΔEads of NO, NH3 on Cu/SAPO-11
and the change of energy of the reduction reaction are presented. The energy profle of the formation of NH2NO–Cu/
SAPO-H key intermediate is shown. Some relevant charges and bond indexes were calculated. On adsorbing NH3 or NO
on Cu/SAPO-11 there is charge transfer to the aggregates. Vibrational frequencies of adsorbed NH3, NO and of NH2NO–
Cu/SAPO-11cluster are reported. The importance of adsorbing NH3 previously to the reduction of NO is emphasize
Feeding of Arapaima sp.: integrating stomach contents and local ecological knowledge
Get PDFThe giant arapaima (Arapaima sp.) has been described as a fish of change in Amazonia because of its important role in the conservation of floodplains, food security and income generation for rural communities. Nonetheless, despite the cultural, ecological and economic importance of arapaima, data on diet are scarce. Aiming to expand knowledge about arapaima diet in western Amazonia, scientific knowledge was integrated with the knowledge of local dwellers. During the low‐water period (September 2018) and the falling‐water period (June 2019), arapaima stomachs were collected from 11 floodplain lakes in the middle Juruá River. All fishes were measured [TL (total length)] and sexed. Food items from each stomach were categorized as fishes, invertebrates, plants and bone remains and weighed. Also, in the latter period, experienced local fishers were interviewed about arapaima feeding. This integrated approach revealed that young arapaima eat fish and invertebrates but adult arapaima eat fish of a wide range of species, which were mainly of low and intermediate trophic positions. This study reports the first case of cannibalism for arapaima and also shows that during the low‐water period, many individuals had empty stomachs or only some small fish‐bone remains and/or plant material. Arapaima sex and TL had no influence on the absence of prey in stomach contents. Overall, it can be concluded that local people had consistent ethnobiological knowledge of arapaima feeding ecology that could be useful within management projects in the region
Assessing the stability of historical and desiccated snake venoms from a medically important Ecuadorian collection
Get PDFBothrops asper and Bothrops atrox are important venomous snakes from Ecuador responsible for the most of ophidic accidents, which in the past were treated with a national polyvant antivenom. For years, the venom pools were collected and stored at room temperature in a laboratory. Taking into account the controversial ability of desiccated samples to retain their biological effects and enzymatic activities, we investigated the biochemical and toxicological properties of venoms after years of storage. The proteomic profiles of historical venoms analyzed by high-performance liquid chromatography and electrophoresis are very similar. The fresh batches of venom were more lethal than those stored for years, just as the initial and current LD50 values of these samples changed. Significant differences were showed in the myotoxic and hemorrhagic activity of some venom pools, while no significant statistical differences were found for the edema activity. The enzymatic assays revealed a variation in proteolytic activity on azocasein and phospholipase A2 activity, and low differences were reported for thrombin-like serine protease activity. The maintenance of the proteomic profile and certain toxicological activities convert this venom library in a valuable source for research purposes. Nonetheless, the significative reduction of toxicological activities, such as hemorrhagic activity not feasible using these samples for the antivenom production
Towards Industry Improvement in Manufacturing with DMAIC
Get PDFToday, the accelerated development of industry 4.0 and the immer-
sion of technologies with the DMAIC methodology, Lean Manufacturing allows
higher productivity and continuous improvement of industrial processes. There
are countless manufacturing companies, of which very few have invested in tech-
nology and methodologies, so they have not been able to prepare themselves to
advance at the same pace as the industrial revolution. This research proposes to
include improvements in the manufacture of furniture by applying software tools
and methodologies such as DMAIC, which consists of combining the application
of some tools such as Lean, visual management, and standardized work. As a
case study, we applied to the manufacture of furniture; the results indicated that
by applying DMAIC and simulation tools, a significant increase in production
was achieved, with a decrease in delivery time, in addition to the optimization
and reduction of waste. This research can serve as a reference for future studies
related to manufacturing processes when applying DMAIC, Lean Manufacturing,
and simulation software
A new species of Leucostethus (Anura: Dendrobatidae) from the Cordillera Mache-Chindul in northwestern Ecuador, with comments on similar Colostethus and Hyloxalus
Get PDFWe describe a new species of dendrobatid frog, Leucostethus bilsa sp. nov., using molecular, morphological, and acoustic evidence. We also comment on the taxonomic status of four similar Hyloxalus and Colostethus. We provide an updated phylogeny of Leucostethus that corroborates previous hypotheses of relationships of nine species. Phylogenetic analysis using mitochondrial (i.e., 7095 bp of combined data from NADH1, NAHD2, cytochrome c oxidase I, cytochrome b and 12S-16S rRNA) and seven nuclear genes (i.e., 4739 bp) indicate a close relationship of L. bilsa to an undescribed species from Gorgona Island, Colombia, both of which apparently diverged in the Pliocene about 3 million years ago with about 6.25% (i.e., 146/2335 bp) differences for the section of 12S-16S mitochondrial fragment. Leucostethus bilsa is diurnal and riparian, characterized by distinctive bright mustard-yellow flash marks in the axillar and groin regions, posterior belly, and in the hindlimbs, the presence of dark gray lower labial stripe or marks, sexual dimorphism in ventral pattern, and by having male uniparental care. We describe its osteology and the male advertisement call, which is a series of peep notes. Osteological microCT images of representatives of each of the Colostethinae genera reveal a number of intriguing characters that may prove to be useful in phylogenetic studies. In terms of its distribution, Leucostethus bilsa is currently known only from a very small area within the Reserva Biológica Bilsa, located within the Cordillera Mache-Chindul in the Chocoan region of northwestern Ecuador, which was a Pliocene-Pleistocene refugium. This region is highly threatened with habitat degradation and remains as the last surviving refuge for a forest community known for a high proportion of endemic species of both flora and fauna