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How Do Negative Emotions Influence on the Conceptual Models Verification?: A live study proposal
No full textThe present live study is proposed with the objective of investigating the influence of negative emotions (i.e., stress) in the efficiency for verifying conceptual models. To conduct this study, we use a Model-driven Testing tool, named CoSTest, and our own version of stress detector within a competition setting. The experiment design, overview of the empirical procedure, instrumentation and potential threats are presented in the proposal. © 2020 ACM.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Ultraviolet Concentration Factor of a Truncated Compound Parabolic Concentrator under Different Weather Conditions
No full textAbstract—: This study presents the results of ultraviolet radiation measurement in a truncated compound parabolic concentrator. The measurements were performed by using of a portable ultraviolet sensor both inside and outside the concentrator without the presence of receiver, under direct and diffuse solar radiation, to calculate the real value of the concentration factor of ultraviolet radiation. The truncated compound parabolic concentrator was designed in Solid Works and built via 3D printing, with a theoretical concentration factor of 4.6. This study showed the differences in the form of the ultraviolet radiation when measurements were made under direct radiation and diffuse solar radiation. These differences are important when measurements were made along the concentrator profile, at different heights within the concentrator and, also, along it. Finally, a concentration factor of 3.3 and 1.4 were calculated on a sunny and a cloudy days, respectively. These values correspond to a concentration efficiency of 71.7 and 31.3%, respectively, against the theoretical value of 4.6 proposed in the design. © 2020, Allerton Press, Inc.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Rainfall characteristics in the mantaro basin over tropical andes from a vertically pointed profile rain radar and in-situ field campaign
No full textInformation on the vertical structure of rain, especially near the surface is important for accurate quantitative precipitation estimation from weather and space-borne radars. In the present study, the rainfall characteristics, from a vertically pointed profile Radar in the Mantaro basin (Huancayo, Peru) are observed. In summary, diurnal variation of near-surface rainfall and bright band height, average vertical profiles of the drop size distribution (DSD), rain rate, radar reflectivity (Ze) and liquid water content (LWC) are investigated to derive the rainfall characteristics. Diurnal variation of rain rate and bright band height show the bimodal distribution, where frequent and higher rain rate occurred during the afternoon and nighttime, and more than 70% bright band height found between 4.3-4.7 km. The average vertical profiles of Ze show the opposite characteristics above and below the melting level (ML) and depend on the near-surface rain rate. For example, the average Ze profiles have a negative gradient above the ML, whereas below, the ML, the gradient depends on the near-surface rain rate. The rain rate and LWC show the opposite behavior, and both consist of a positive (negative) gradient below (above) the ML. The vertical growth of DSD parameters depend on the near-surface rain rate, and a higher concentration of large-sized of droplets are observed for higher near surface rain rate, however, the dominant modes of droplets are <1 mm throughout the vertical column. However, the most significant variation in DSD growth is observed for near-surface rain rate ?20 mm/h. These findings suggest using different retrieval techniques for near surface rain estimation than the rest of the vertical profile and high rain rate events. The improved understanding of the tropical Andes precipitation would be very important for assessing climate variability and to forecast the precipitation using the numerical models. © 2020 by the authors.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Tree influence exacerbates the El Niño effects over soil CO2 emissions and its microclimatic controls
No full textDryland ecosystems are considered the largest global carbon sink. However, extreme climate phenomena like the El Niño events (EN) may change soil respiration (Rs) – the CO2 emitted from soils resulting from biological activity and the largest outgoing flux of carbon from terrestrial ecosystems. Our aim was to study the effect of the EN on Rs in the North Peruvian dryland forest, and its interaction with soil temperature and the tree canopy. Our results indicate that Rs during the EN years increased by a factor of 100 compared to normal years, but this effect was exacerbated by the proximity to trees. Only under trees and during the EN event temperature exerted a positive control over daily Rs fluctuations. Our results, indicate how in these dryland forests the expected increase in the EN frequency and intensity could affect soil CO2 emissions, and hence ecosystem carbon budgets, but that this effect would very much depend on tree density and tree spatial distribution. © 2019 Elsevier B.V.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Mechanical characterization of a masonry system made of alkaline activated pozzolana blocks
No full textThe development of alkaline activated materials has enabled the production of eco-friendly alternatives for the construction industry. In the present article, the mechanical characterization of a new structural masonry system composed of fiber-reinforced lightweight pozzolana-based blocks and cement-lime mortar was performed. The mechanical characterization involved uniaxial compression tests in prisms and diagonal compression in wallets. The results indicate that the compressive and shear strength of the masonry system is up to 3.24 MPa and 0.38, respectively. The results obtained indicate that the evaluated system is structurally efficient and that can be used as both non-load and load-bearing walls. © 2020 Trans Tech Publications Ltd, Switzerland.Fondo Nacional de Desarrollo Científico y Tecnológico - Fondecy
Treatment of irrigation water infested with nematodes using a solar photoreactor
No full textThe objective of this study was to assess the efficacy of the disinfection of irrigation water loaded with the plant-parasitic nematode Meloidogyne incognita using a solar photoreactor. The photoreactor was comprised of a compound parabolic concentrator and a disinfection chamber made of boro-silicate glass where a static mixer coated or uncoated with TiO2 was installed. Water loaded with M. incognita was exposed to solar radiation within the reactor and recirculated while accumulated ultraviolet (UV) energy was registered. It was determined that an accumulated UV solar energy of 72 kJ/L inhibited the motility of juveniles while accumulated energy of 215 kJ/L was necessary to inhibit the egg hatching. Plants of lettuce irrigated with the treated water showed significantly less nodulation, higher air-dry weight and root dry-weight compared with the control group. No significant differences were found using the static mixer either coated with TiO2 or uncoated. © 2020 Desalination Publications.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Peruvian scallop Argopecten purpuratus: From a key aquaculture species to a promising biondicator species
No full textThe present study analyzed the Peruvian scallop Argopecten purpuratus and its food sources for metal and fatty acid concentrations in order to determine spatial and temporal differences. Metals such as copper (Cu), manganese (Mn), and zinc (Zn) in gills and iron (Fe) and Zn in sediments were the most significant explaining factors for spatial differentiations (degree of contamination), while for fatty acids, it was C14:0, C15:0, C16:0 and C18:0 in A. purpuratus' muscle and in its food sources, which explained more temporal differences (El Niño-Southern Oscillation (ENSO) effect). Gills, digestive gland and intestine were the tissues where metal accumulation was the highest in A. purpuratus. Cd in digestive gland was always high, up to ∼250-fold higher than in other tissues, as previously reported in other bioindicator species for metal pollution. Fatty acids were good biomarkers when annual comparisons were performed, while metals when locations were compared. ENSO 2017 played an important role to disentangle A. purpuratus’ biological conditions and food sources. A. purpuratus from Paracas locations mostly showed higher metal concentrations in gills and digestive glands, and lower fatty acid concentrations in muscle than those from Sechura and Illescas Reserved Zone. © 2019 Elsevier LtdFondo Nacional de Desarrollo Científico y Tecnológico - Fondecy
Shrimp farming influence on carbon and nutrient accumulation within Peruvian mangroves sediments
No full textIn order to investigate the influence of shrimp farming activities on carbon and nutrient accumulation, sediment cores were collected from two areas at different distances from shrimp farms within a Peruvian mangrove ecosystem. In both areas two sediment cores were collected in a transect, one from a mangrove-covered site and one from a mudflat site. At both study sites, the isotopic values of carbon and nitrogen as well as the C:N molar ratios suggest that the highest carbon accumulation rates were linked to terrestrial-derived organic matter, with higher carbon stocks and fluxes within mangrove-covered zones. The historical records indicate that since the mid-1970's, the areas nearest to the shrimp farming activity have been accumulating higher proportions of algal derived organic matter, which were likely triggered by the high nutrient influx derived from shrimp farming effluents. The carbon and nutrient fluxes were up to threefold higher within the area nearest to the shrimp farms, whereas the geochronologies showed that the carbon and nutrient stocks in this area increased by up to twofold. The results showed that mangrove-covered zones are more capable to keep pace with sea level rise (SLR) as compared to the mudflat zones, indicating the importance of mangrove vegetation in terms of the vulnerability of this region to SLR and an ongoing capacity to continue accumulating sediments. This study highlights the role that mangrove vegetation plays in mitigating the impact of shrimp farming activities, accumulating carbon and nutrients in pace with SLR.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Mycobacterium tuberculosis ribosomal protein S1 (RpsA) and variants with truncated C-terminal end show absence of interaction with pyrazinoic acid
No full textPyrazinamide (PZA) is an antibiotic used in first- and second-line tuberculosis treatment regimens. Approximately 50% of multidrug-resistant tuberculosis and over 90% of extensively drug-resistant tuberculosis strains are also PZA resistant. Despite the key role played by PZA, its mechanisms of action are not yet fully understood. It has been postulated that pyrazinoic acid (POA), the hydrolyzed product of PZA, could inhibit trans-translation by binding to Ribosomal protein S1 (RpsA) and competing with tmRNA, the natural cofactor of RpsA. Subsequent data, however, indicate that these early findings resulted from experimental artifact. Hence, in this study we assess the capacity of POA to compete with tmRNA for RpsA. We evaluated RpsA wild type (WT), RpsA A438, and RpsA A438 variants with truncations towards the carboxy terminal end. Interactions were measured using Nuclear Magnetic Resonance spectroscopy (NMR), Isothermal Titration Calorimetry (ITC), Microscale Thermophoresis (MST), and Electrophoretic Mobility Shift Assay (EMSA). We found no measurable binding between POA and RpsA (WT or variants). This suggests that RpsA may not be involved in the mechanism of action of PZA in Mycobacterium tuberculosis, as previously thought. Interactions observed between tmRNA and RpsA WT, RpsA A438, and each of the truncated variants of RpsA A438, are reported.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Exact solution of thermo-mechanical analysis of laminated composite and sandwich doubly -curved shell
No full textThis paper presents an exact solution for doubly-curved shells subjected to thermal loads. The solution is based on equilibrium equations. The through-the-thickness shell temperature is calculated using the Fourier’s heat conduction equation. The governing equations for displacement and temperature are solved using Navier method, which is valid for shell panels with constant curvature and simply-supported edges.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte