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Azorella compacta's long-term growth rate, longevity, and potential for dating geomorphological and archaeological features in the arid southern Peruvian Andes
No full textWe determine the long-term growth rate and longevity of an Azorella compacta growing on Misti volcano, near Arequipa, Peru to investigate the species' capacity as a geochronological resource. Using 14C dating on stem pieces sequestered within the plant's cushion, which grows larger through time, we obtain ages of 15 ± 15 14C yrs BP and 165 ± 15 14C yrs BP at depths of 15 cm and 29 cm below the cushion's living surface, respectively. Applying a mixed calibration curve with a Bayesian growth model yields calendar age ranges of 1948–1958 CE and 1802–1935 CE for our 14C dates, respectively. Such ages provide sufficiently precise constraints for investigations requiring dating during the last few hundred years when individual 14C dates yield imprecise calendar age ranges. We infer a long-term growth rate of 1.3–3.5 mm yr?1, corroborating published maximum short-term growth rates. Extrapolating our growth model to the A. compacta's core suggests that it began growing as early as 1462–1830 CE. At such age it lived through myriad important geological and historical events, including regional earthquakes, volcanic unrest at Misti, decades to centuries of the Little Ice Age, and a broad transect of Peruvian history possibly beginning during the Inca Empire. A. compacta may provide another important geochronological resource in the arid Central Andes that can be applied to date volcanological, glacial, mass-movement, and archaeological features, especially where dendrochronology and lichenometry are not possible. © 2021Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Soot modeling in turbulent diffusion flames: review and prospects
No full textThis work reviews the state of the art of the main soot modeling approaches used in turbulent diffusion flames. Accordingly, after a short introduction about the subject addressed here, the main soot formation mechanisms are described next. This description provides the basis for the discussions about the different soot modeling techniques employed nowadays for soot predictions. Since combustion and radiation models have a significant impact on soot predictions, as a consequence of the strong coupling between chemistry, turbulence and soot formation, a general overview about these models is also provided. For the sake of clarity, the main soot formation models reviewed in this work are classified as semiempirical soot precursor models and detailed ones. Both advantages and disadvantages of the referred soot modeling approaches are properly discussed. In the last part of this review, comparative results obtained using some of the main soot models currently available are presented along with a discussion about the prospects for soot modeling in turbulent flames. Finally, some conclusions and references are provided. Overall, based on the literature reviewed, it is concluded that there is yet a long path to be followed before understanding first and having then a soot model able to properly describe the formation of this critical pollutant for a variety of situations of industrial interest. © 2021, The Brazilian Society of Mechanical Sciences and Engineering.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Geometry-induced enhancement factor improvement in covered-gold-nanorod-dimer antennas
No full textIlluminated gapped-gold-nanorod dimers hold surface plasmon polaritons (SPPs) that can be engineered, by an appropriate choice of geometrical parameters, to enhance the electromagnetic field at the gap, allowing applications in molecular detectionviasurface-enhanced Raman spectroscopy (SERS). Envisioning hybrid devices in which the SERS spectroscopy of molecules in the gap is complemented by electrical measurements, it arises the question of designing efficient geometries to contact the nanorods without decreasing the enhancement factor (EF) of the nanoantenna,i.e., the figure of merit for SERS spectroscopy. Within this framework we theoretically study the feasibility to fabricate designs based on covering with gold the far-from-the-gap areas of the dimer. We show that by tuning the geometrical parameters of the designs these systems can reach enhancement factors larger than the best achieved in the uncovered dimer: this supremacy survives even in the presence of dimer asymmetries and vacancies at the interfaces between the nanorods and the covering layers. Our results show that geometrical modifications away from the gap can improve the optical response at the gap, thus enabling the use of these devices both for hybrid and optical applications. © The Royal Society of Chemistry 2021.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Existence of solution for a class of variational inequality in whole RN with critical growth
No full textIn this paper we study the existence of solution for a class of variational inequality in whole
. The main tools used are the penalization method due to Bensoussan & Lions [8] and the Mountain Pass Theorem due to Ambrosetti & Rabinowitz [3].Rabinowitz [3]. © 2020 Elsevier Inc
Mechanical characterization of new geopolymeric materials based on mining tailings and rice husk ash
No full textThis work presents the results of the thermomechanical evaluation of geopolymeric concrete fabricated from mining tailings, rice husk ash and fine sand. Ten types of geopolymeric concrete were studied and the relationship between the initial volumetric concentrations of the components in the mixtures and the maximum resistance in uniaxial compression under conditions of variable temperature (between ambient and 600 ºC) was analyzed. The results revealed that increases in the concentration of mining tailings and fine sand lead to an increase in the value of the maximum mechanical resistance, in contrast, the increase in the concentration of rice husk ash led to a reduction in the value of the maximum mechanical resistance. Furthermore, increases in test temperature, up to 500 °C, led to systematic increases in maximum mechanical strength. Finally, the geopolymeric concretes presented a brittle-ductile transition between 500 and 600 °C showing only a ductile behavior when tested at 600 °C and only brittle up to test temperatures of 500 °C.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Emotion detection for social robots based on nlp transformers and an emotion ontology
No full textFor social robots, knowledge regarding human emotional states is an essential part of adapting their behavior or associating emotions to other entities. Robots gather the information from which emotion detection is processed via different media, such as text, speech, images, or videos. The multimedia content is then properly processed to recognize emotions/sentiments, for example, by analyzing faces and postures in images/videos based on machine learning techniques or by converting speech into text to perform emotion detection with natural language processing (NLP) techniques. Keeping this information in semantic repositories offers a wide range of possibilities for implementing smart applications. We propose a framework to allow social robots to detect emotions and to store this information in a semantic repository, based on EMONTO (an EMotion ONTOlogy), and in the first figure or table caption. Please define if appropriate. an ontology to represent emotions. As a proof-of-concept, we develop a first version of this framework focused on emotion detection in text, which can be obtained directly as text or by converting speech to text. We tested the implementation with a case study of tour-guide robots for museums that rely on a speech-to-text converter based on the Google Application Programming Interface (API) and a Python library, a neural network to label the emotions in texts based on NLP transformers, and EMONTO integrated with an ontology for museums; thus, it is possible to register the emotions that artworks produce in visitors. We evaluate the classification model, obtaining equivalent results compared with a state-of-the-art transformer-based model and with a clear roadmap for improvement. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Healthcare of Indigenous Amazonian Peoples in response to COVID-19: Marginality, discrimination and revaluation of ancestral knowledge in Ucayali, Peru
No full textSystematic and persistent discrimination against Indigenous Peoples translates into differential health outcomes when analysed through ethnicity and/or mother tongue.1 In Peru, morbidity and mortality rates among Indigenous Peoples for COVID-19 appear to confirm thisConsejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Evaluation of the antioxidant activities of aqueous extracts from seven wild plants from the Andes using an in vivo yeast assay
No full textThe antioxidant activities of the aqueous extracts of seven wild plants were investigated, using both in vitro and in vivo assays. The former relied on the use of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and the latter, on the sensibility towards hydrogen peroxide of the yeast sod1 mutant. The studied plants were all wild, collected at the Ccamarrara hill (4000 m.a.s.l. Cusco, Peru), and of the following species: Plantago australis, Baccharis latifolia, Ageratina sternbergiana, Stevia macbridei, Ageratina cuzcoensis, Calceolaria myriophylla, and Adiantum orbignyanum. The DPPH assay demonstrated high antioxidant contents in the dry leaves of all tested plants, with AAEAC values (ascorbic acid equivalent antioxidant capacity) ranging from 20.6 to 72.7 mg/g dry leaves. The antioxidant activities were also evident in the yeast assay, which also allowed distinction between the intracellular and extracellular effects. These in vitro and in vivo studies demonstrate the need to further investigate native wild plants from the Andes as important sources for water-soluble antioxidant compounds. © 2021 The AuthorsFondo Nacional de Desarrollo Científico y Tecnológico - Fondecy
Efficient cloning of tilapia lake virus complementary DNAs using an in vivo strategy in baker's yeast
No full textCloning and protein expression in heterologous systems are very useful tools for the study of viral proteins. In this work, an in vivo cloning strategy was applied using the yeast Saccharomyces cerevisiae, as an efficient and low-cost method to clone several cDNAs from the tilapia lake virus (TiLV). Samples of infected tilapia Oreochromis niloticus tissues were taken and used to isolate their RNA and to obtain and clone the ten viral cDNAs in a shuttle plasmid. The cloning efficiencies range from 5 to 100% but for seven of the cDNAs the values were above 40%, demonstrating the high efficiency of the method. © 2021 The Authors. Journal of the World Aquaculture Society published by Wiley Periodicals LLC on behalf of World Aquaculture Society.Fondo Nacional de Desarrollo Científico y Tecnológico - Fondecy
Infinitely many solutions for a nonlocal type problem with sign-changing weight function
No full textIn this article, we study the existence of weak solutions for a fractional type problem driven by a nonlocal operator of elliptic type (-Δ)sa1u - λa2(|u|)u = ƒ(x, u) + g(x)|u|q(x)-2u in Ω u = 0 in ℝN \ Ω. Our approach is based on critical point theorems and variational methods.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte