2.2 Estudios de maestría
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PublicaciónA method to include life cycle assessment results in choosing by advantage (Cba) multicriteria decision analysis. a case study for seismic retrofit in peruvian primary schools(MDPI AG, 2021)
;Vázquez-Rowe I. ;Córdova-Arias C. ;Brioso X.Santa-Cruz S.Building information modeling (BIM) is an emerging technology that improves visualization, understanding, and transparency in construction projects. Its use in Latin America and the Caribbean (LA&C), while still scarce, is developing in combination with multi-criteria decision-making (MCDM) methods, such as the choosing by advantages (CBA) method. Despite the holistic nature of MCDM methods, the inclusion of life cycle environmental metrics is lagging in construction projects in LA&C. However, recent studies point toward the need to optimize the synergies between BIM and life cycle assessment (LCA), in which a method like CBA could allow improving the quality of the decisions. Therefore, the main objective of this study is to integrate LCA and CBA methods to identify the effect that the inclusion of environmental impacts can have on decision-making in public procurement, as well as comparing how this final decision differs from an exclusively LCA-oriented interpretation of the results. Once the LCA was performed, a set of additional criteria for the CBA method were fixed, including transparency, technical, and social indicators. Thereafter, a stakeholder participative workshop was held in order to gather experts to elucidate on the final decision. The methodology was applied to a relevant construction sector problem modelled with BIM in the city of Lima (Peru), which consisted of three different construction techniques needed to retrofit educational institutions. Results from the LCA-oriented assessment, which was supported by Monte Carlo simulation, revealed a situation in which the masonry-based technique showed significantly lower environmental impacts than the remaining two options. However, when a wider range of technical, social, and transparency criteria are added to the environmental indicators, this low-carbon technique only prevailed in those workshop tables in which environmental experts were present and under specific computational assumptions, whereas teams with a higher proportion of government members were inclined to foster alternatives that imply less bureaucratic barriers. Finally, the results constitute an important milestone when it comes to including environmental factors in public procurement in LA&C. © 2021 by the author. Licensee MDPI, Basel, Switzerland. -
PublicaciónAgro-industrial waste seeds from Peruvian Pouteria lucuma as new source of phytosterols(Academic Press, 2021)
;Guerrero-Castillo P. ;Reyes S. ;Acha O. ;Sepulveda B.Areche C.Pouteria lucuma fruit is commonly used to prepare desserts, but it is also sold as pulp or flour. Then, huge amounts of its seeds are produced as agro-industrial waste, frequently eliminated. This study aims at analyzing the presence of all metabolites in Pouteria lucuma seed oil (LSO) by GC-MS and GC-FID. Several compounds were tentatively identified, such as fatty acids, fatty alcohols, carotenes, phytosterols and tocopherols from LSO. A representative result was the high amount of β-sitosterol with 851.49 ± 1.29 mg/100 g of LSO, followed by stigmasterol with 75.42 ± 1.02 mg/100 g. Fatty acids with the highest content were oleic acid (13.57 ± 1.50 g/100 g of LSO), 9E-octadecenoic acid (6.85 ± 1.15 g/100 g of LSO), palmitic acid (5.44 ± 1.18 g/100 g of LSO) and stearic acid (2.12 ± 1.03 g/100 g of LSO). Therefore, metabolites tentatively identified in Pouteria lucuma seed oil have been linked to healthy properties based on a high amount of β-sitosterol present. This evidence could determine this agro-industrial waste with having beneficial properties, thus providing great added value. -
PublicaciónAmbient lighting generation for flash images with guided conditional adversarial networks(SciTePress, 2020)
;Chávez J. ;Mora R.Cayllahua-Cahuina E.To cope with the challenges that low light conditions produce in images, photographers tend to use the light provided by the camera flash to get better illumination. Nevertheless, harsh shadows and non-uniform illumination can arise from using a camera flash, especially in low light conditions. Previous studies have focused on normalizing the lighting on flash images; however, to the best of our knowledge, no prior studies have examined the sideways shadows removal, reconstruction of overexposed areas, and the generation of synthetic ambient shadows or natural tone of scene objects. To provide more natural illumination on flash images and ensure high-frequency details, we propose a generative adversarial network in a guided conditional mode. We show that this approach not only generates natural illumination but also attenuates harsh shadows, simultaneously generating synthetic ambient shadows. Our approach achieves promising results on a custom FAID dataset, outperforming our baseline studies. We also analyze the components of our proposal and how they affect the overall performance and discuss the opportunities for future work. -
PublicaciónAn interdisciplinary approach to identify zones vulnerable to earthquakes(Elsevier Ltd, 2020)
;Izquierdo-Horna L.Kahhat R.Earthquakes in Peru are responsible for enormous material and human losses. One of the reasons for the latter is that risk and disaster management policies do not consider individuals as a significant factor for planning post-disaster activities. An understanding of all-important aspects that influence post-disaster efforts would reduce the number of dead, injured and affected people as well as the required money and time to invest. This research develops an interdisciplinary approach, based on seismic vulnerability, to identify those zones that need immediate attention after an earthquake. We consider vulnerability to be a result of two dimensions: social and physical. The first describes society by its anthropogenic characteristics through social indicators (age, daily income, education, etc.). The second describes the built environment and the main features of infrastructure. The results show that the physical and social dimensions intersect and interact with fairly consistent regularity. Thus, we are then able to more accurately identify the areas that require higher prioritization in an emergency scenario. Having this data available for regions predisposed to earthquakes will allow for substantial improvements to current risk mitigation action plans as well as the promotion of a more comprehensive prevention effort. -
PublicaciónAnti-Helicobacter pylori Properties of the Ant-Venom Peptide Bicarinalin(MDPI, 2018)
;Guzman, J ;Tene, N ;Touchard, A ;Castillo, D ;Belkhelfa, H ;Haddioui-Hbabi, L ;Treilhou, MSauvain, MThe venom peptide bicarinalin, previously isolated from the ant Tetramorium bicarinatum, is an antimicrobial agent with a broad spectrum of activity. In this study, we investigate the potential of bicarinalin as a novel agent against Helicobacter pylori, which causes several gastric diseases. First, the effects of synthetic bicarinalin have been tested against Helicobacter pylori: one ATCC strain, and forty-four isolated from stomach ulcer biopsies of Peruvian patients. Then the cytoxicity of bicarinalin on human gastric cells and murine peritoneal macrophages was measured using XTT and MTT assays, respectively. Finally, the preventive effect of bicarinalin was evaluated by scanning electron microscopy using an adherence assay of H. pylori on human gastric cells treated with bicarinalin. This peptide has a potent antibacterial activity at the same magnitude as four antibiotics currently used in therapies against H. pylori. Bicarinalin also inhibited adherence of H. pylori to gastric cells with an IC50 of 0.12 μg·mL−1 and had low toxicity for human cells. Scanning electron microscopy confirmed that bicarinalin can significantly decrease the density of H. pylori on gastric cells. We conclude that Bicarinalin is a promising compound for the development of a novel and effective anti-H. pylori agent for both curative and preventive use. -
PublicaciónAntimicrobial sensitivity of pathogenic Yersinia ruckeri from central and southern highlands of Peru(Blackwell Publishing Ltd, 2020)
;Mesías Valle F. ;Llanco L. ;Serrano-Martínez E. ;Hurtado C. ;Rodríguez T.Smith P.The objectives of this study were to establish the phenotypic antimicrobial sensitivity of the isolates from Peruvian rainbow trout using the procedures recommended by OIE -
PublicaciónAre Ionic Liquids Better Extracting Agents Than Toxic Volatile Organic Solvents? A Combination of Ionic Liquids, Microwave and LC/MS/MS, Applied to the Lichen Stereocaulon glareosum(Frontiers Media S.A., 2020)
;Calla-Quispe E. ;Robles J. ;Areche C.Sepulveda B.We report a green strategy for the extraction of lichen substances from Stereocaulon glareosum. This sustainable alternative does not use volatile toxic organic solvents, but it is assisted by microwave and is checked by UHPLC/ESI/MS/MS. Ionic liquids may provide a better alternative in the extraction of natural products from lichens. © Copyright © 2020 Calla-Quispe, Robles, Areche and Sepulveda. -
PublicaciónAssessing soil erosion risk at national scale in developing countries: The technical challenges, a proposed methodology, and a case history(Elsevier B.V., 2020)
;Rosas M.A.Gutierrez R.R.Through an extensive bibliographic review, this contribution underlines the urgency and challenges to quantify soil erosion rates (ERs) in developing countries. It subsequently elaborates on the combined application of GIS-based RUSLE, generalized likelihood uncertainty estimation (GLUE) principles and sediment delivery ratio functions (SDR) to quantify ERs at country scale for these countries, as they commonly have limited measurements to that purpose. The methodology, termed RUSLE-GGS (RUSLE-GIS-GLUE-SDR) herein, comprises the following sequence: (1) construction of ER samples using RUSLE-GIS based on freely available local/global geoenvironmental observations and field relations, (2) construction of area-specific sediment yield samples utilizing SDR transfer functions, and (3) assessment of the most behavioral samples by means of bias analysis and cross validation. Its application to Peru allows obtaining 5-km resolution ER and potential erosion maps for the years 1990, 2000, and 2010. RUSLE-GGS is highly replicable and could potentially be used as an initial standard and systematic method to estimate ERs in developing countries through the active participation of local scientists. Thus, it potentially can contribute to improve the capacity building in such countries and set an initial frame to compare the evolution of soil erosion in their territories towards attaining Goal 15 of the UN 2030 Agenda for Sustainable Development. -
PublicaciónAssessment of heterotrophic nitrification capacity in Bacillus spp. And its potential application in the removal of nitrogen from aquaculture water(Journal of Pure and Applied Microbiology, 2019)
;Mendoza L.F.D. ;Mujica J.G.Q. ;Cunayque J.M.R. ;Lucana G.W.A. ;Angulo J.J.I. ;De La Cruz V.I.S. ;Escobar V.A.C.Matonnier E.M.The accumulation of nitrogen (-N) is a serious problem in aquaculture as it could lead to mass mortality events of the cultivated species. Chemilitotrophic nitrification is the most recognized in nitrogen removal underestimating the role of heterotrophic nitrifiers. In the present study, the heterotrophic nitrification capacity of 8 bacterial strains isolated from mangrove soil, periphyton and biofilters was evaluated. The strains were grown in heterotrophic nitrification base medium (HNM medium) with three different nitrogen sources, ammonium, nitrite or nitrate at a final concentration of 8 mg L-1, 5 mg L-1 and 80 mg L-1 respectively. The concentration of nitrogen (-N) and OD (600 nm) were determined periodically. Only in 4 strains belonging to the Bacillus genus was the capacity for heterotrophic nitrification and aerobic denitrification observed. Among these strains, SM4 strain presented a good removal profile of ammonium, nitrite and nitrate, achieving an average nitrification efficiency of 98.33 ± 2.89%, 83.67 ± 7.51% and 98.00 ± 0.01% respectively, and a nitrification rate (mg L-1 h-1) of 1.71 ± 0.70, 0.13 ± 0.07 and 0.21 ± 0.06 respectively. The nxrB, nirS, nirK genes in the selected strains were identified by PCR. Additionally, several proteins (enzymes) involved in the nitrogen cycle were identified by proteomic analysis, reporting for the first time the presence of the enzymes ammonia monoxygenase (AMO) and nitrite oxide reductase (NXR) in the genus Bacillus. These findings suggest that the strains studied would have a potential use in the biological removal of nitrogen in aquaculture systems. -
PublicaciónAtomic scale study of silver sulfide leaching with cyanide and thiourea(Oficyna Wydawnicza Politechniki Wroclawskiej, 2019)
;Bernaola-Flores, R ;Silva-Quinones, D ;Balbuena, PB ;Rodriguez-Reyes, JCFTarazona-Vasquez, FEs necesario comprender las interacciones a escala atómica de las especies moleculares con las superficies minerales para lograr la innovación en el procesamiento de minerales. En este sentido, los métodos de la teoría funcional de la densidad (DFT) son muy adecuados. En este trabajo, se estudia el resultado de la lixiviación de acantita sintética, un sustituto de un mineral de sulfuro que contiene plata, con ion cianuro y tiourea con DFT considerando los efectos del solvente. Los resultados se correlacionan con el porcentaje experimental de plata extraído con cada uno de los agentes de lixiviación en condiciones similares de concentración molar, temperatura y porcentaje de sólidos. Nuestros cálculos muestran que ambas reacciones de lixiviación son exergónicas y del mismo orden de magnitud en energía de reacción de Gibbs que los valores determinados a partir de tablas termodinámicas. También, Se obtienen energías de reacción de Gibbs menos favorables para la cianuración en ausencia de oxígeno y la tioureación en ausencia de Fe (II), destacando el impacto de los oxidantes en la exergonicidad de las respectivas reacciones de lixiviación global. Finalmente, analizando el porcentaje de plata extraída de la acantita y el valor absoluto de las energías de Gibbs de la respectiva reacción, se concluye que cuanto más exergónica es una reacción de lixiviación, mayor porcentaje de plata se extrae de la acantita, siempre que no exista un control cinético de cada una de las reacciones de lixiviación. -
PublicaciónBandgap Engineering of Amorphous Hydrogenated Silicon Carbide(Materials Research Society, 2016)
;Guerra J.A. ;Montañez L.M. ;Tucto K. ;Angulo J. ;Töfflinger J.A. ;Winnaker A.Weingärtner R.A simple model to describe the fundamental absorption of amorphous hydrogenated silicon carbide thin films based on band fluctuations is presented. It provides a general equation describing both the Urbach and Tauc regions in the absorption spectrum. In principle, our model is applicable to any amorphous material and it allows the determination of the bandgap. Here we focus on the bandgap engineering of amorphous hydrogenated silicon carbide layers. Emphasis is given on the role of hydrogen dilution during the deposition process and post deposition annealing treatments. Using the conventional Urbach and Tauc equations, it was found that an increase/decrease of the Urbach energy produces a shrink/enhancement of the Tauc-gap. On the contrary, the here proposed model provides a bandgap energy which behaves independently of the Urbach energy. -
PublicaciónBartonella bacilliformis, endemic pathogen of the Andean region, is intrinsically resistant to quinolones(Elsevier, 2010)
;del Valle L.J. ;Flores L. ;Vargas M. ;García-de-la-Guarda R. ;Quispe R.L. ;Ibañez Z.B. ;Alvarado D. ;Ramírez P.Ruiz J.To analyze the sequence of the region involved in the development of quinolone resistance of the gyrA and parC genes in a series of Bartonella bacilliformis isolates recovered prior to the introduction of quinolones, as well as one clinical isolate recovered in the 1970s, establishing the susceptibility levels to nalidixic acid and ciprofloxacin. -
PublicaciónBell violations with entangled and non- entangled optical fields(IOP Publishing, 2019)
;Gonzales, J ;Sanchez, P ;Avalos, VDe Zela, FWe report Bell violations with classical light prepared in both entangled and non-entangled polarization-path, binary states. Our results show that violations of constraints such as the Bell–Clauser–Horn–Shimony–Holt inequality do not necessarily falsify local realism. Correlations in the realm of classical statistical optics, which are not of the Bell type, may lead to Bell violations. -
PublicaciónBiological activity and chemical characterization of Pouteria lucuma seeds: A possible use of an agricultural waste(Elsevier Ltd, 2019)
;Guerrero-Castillo P. ;Reyes S. ;Robles J. ;Simirgiotis M.J. ;Sepulveda B. ;Fernandez-Burgos R.Areche C.Pouteria lucuma fruit is widely used to prepare cakes, ice creams and juice or also commercialized as pulp and flour. As result of this business thousands of tons of seeds are generated as an agricultural waste. This study presents the antioxidant and antiulcer activities, and the identification of secondary metabolites by UHPLC/ESI/MS/MS of an agroindustrial waste of Pouteria lucuma seeds. Fifty-nine compounds were tentatively identified including eight aminoacids, five organic acids, one nucleoside, five phenolic acids, five phenolic alcohols, nineteen flavonoids, six lipids, and seven unknowns in the methanol extract of P. lucuma seeds. The total phenolic content of the seeds was 52.82 ± 0.09 μmol GAE/g dry weight, while total flavonoid content was 5.99 ± 0.01 μmol Q/g dry weight. The antioxidant activity was 58.14 ± 0.05, 66.97 ± 0.00, 272.50 ± 0.00, and 67.02 ± 2.23 for the DPPH, ABTS, FRAP, and superoxide anion assays, respectively. The highest gastroprotective activity was obtained at 100 mg/kg (78%), which as higher than the positive control lansoprazole (75%). Our findings showed that P. lucuma seed extracts have moderate to high antioxidant activity and gastroprotective properties. Therefore, it was demostrated that lucuma seeds commonly eliminated as an agricultural industry waste, could be useful for the preparation of nutritional supplements. -
PublicaciónCalcareous benthic foraminifera from the upper central Peruvian margin: control of the assemblage by pore water redox and sedimentary organic matter(HAL OPEN ACCESS, 2015)
;Cardich, J ;Gutierrez, D ;Romero, D ;Perez, A ;Quipuzcoa, L ;Marquina, R ;Yupanqui, W ;Solis, J ;Carhuapoma, W ;Sifeddine, ARathburn, AWe studied 'living' (stained) benthic foraminifera in the upper border of the Peruvian oxygen minimum zone (OMZ) to determine the relationship between species' distribution and pore water and sediment geochemistry under oxygen deficiency. Superficial sediments were sampled between 2009 and 2011 from 2 bathymetric transects off central Peru (45 to 300 m depth). The quantity (total organic carbon, total nitrogen and chloroplastic pigment equivalents [CPE]) and quality (chlorophyll a/phaeopigments ratio) of organic matter (OM) were evaluated. Benthic foraminifera were sampled in the top 5 cm of sediment. Commonly, the inner shelf sediments were sulfidic and labile OM-rich, whereas the outer shelf and upper slope sediments exhibited postoxic conditions (e.g. anoxic and non-sulfidic) with less labile OM, typical of OMZ core sediments. Mixed conditions were found in shelf sediment samples from April 2010, when the effects of El Niño 2009/2010 were withdrawing. Foraminiferal assemblages exhibited differences according to redox conditions and OM quality, and were concentrated in the topmost sediment. A canonical correspondence analysis and non-parametric correlations indicated that Bolivina costata, Nonionella auris and Virgulinella fragilis were characteristic of sulfidic/labile OM sediments, thriving slightly deeper in the sediment. In contrast, Bolivina pacifica headed the assemblage representative of postoxia/less labile OM. Bolivina seminuda and Buliminella tenuata (both dominant under postoxia) were not associated with any specific measured parameter, although were present in sulfidic sediments, suggesting other factors were involved in their distribution. -
PublicaciónCe alpha Mn1-alpha O2 CATALYSTS SUPPORTED OVER gamma-Al2O3 PREPARED BY MODIFIED REDOX-COPRECIPITATION METHODS FOR n-HEXANE COMBUSTION(Sociedade Brasileira de Quimica (SBQ), 2020)
;Rojas Quispe, Jesus ;Cruz, Romulo ;Sun Kou, RosarioPicasso, GinoA series of Ce alpha Mn1-alpha O2 catalysts supported on gamma-alumina with various molar concentrations of Ce (alpha, from 0 to 0.90) was synthesized by coprecipitation, applying two different precipitating agents, namely, sodium hydroxide (method 1) and sodium carbonate (method 2), with the use of sodium permanganate as a redox agent for precipitation. XRD profiles of the supported samples revealed the predominant abundance of a typical fluorite crystalline structure. TPR thermograms of supported samples were displaced towards lower temperatures with increasing Mn concentration, in contrast with the bulk samples. The supported Ce-Mn samples exhibited a greater performance in n-hexane elimination than did the corresponding simple oxides. The sample Ce0.33M O-0.67(2) obtained by method 2 presented the best activity, probably due to the enrichment of Ce4+, Mn3+ and Mn4+ surface species, an excess of superficial oxygen species and an easy reducibility as well as the lowest apparent activation energy. -
PublicaciónCeαMn1-αO2 CATALYSTS SUPPORTED over g-Al2O3 PREPARED by MODIFIED REDOX-COPRECIPITATION METHODS for n-HEXANE COMBUSTION(Sociedade Brasileira de Quimica, 2020)
;Quispe J.R. ;Cruz R. ;Kou R.S.Picasso G.A series of CeαMn1-αO2 catalysts supported on g-alumina with various molar concentrations of Ce (α, from 0 to 0.90) was synthesized by coprecipitation, applying two different precipitating agents, namely, sodium hydroxide (method 1) and sodium carbonate (method 2), with the use of sodium permanganate as a redox agent for precipitation. XRD profiles of the supported samples revealed the predominant abundance of a typical fluorite crystalline structure. TPR thermograms of supported samples were displaced towards lower temperatures with increasing Mn concentration, in contrast with the bulk samples. The supported Ce-Mn samples exhibited a greater performance in n-hexane elimination than did the corresponding simple oxides. The sample Ce0.33Mn0.67O2 obtained by method 2 presented the best activity, probably due to the enrichment of Ce4+, Mn3+ and Mn4+ surface species, an excess of superficial oxygen species and an easy reducibility as well as the lowest apparent activation energy. -
PublicaciónCholera in Lima, Peru, correlates with prior isolation of Vibrio cholerae from the environment(Oxford University Press, 1997)
;Franco A.A. ;Fix A.D. ;Prada A. ;Paredes E. ;Palomino J.C. ;Wright A.C. ;Johnson J.A. ;McCarter R. ;Guerra H.Glenn Morris Jr. J.The authors utilized a recently developed DNA probe technique to obtain quantitative data on occurrence of Vibrio cholerae in samples collected monthly from 12 environmental sites in Lima, Peru, from November 1993 through March 1995. Peak V. cholerae counts ranged from 1027/ml to 105/ml, with the highest counts in sewage-contaminated areas and irrigation water. With our methodology, no V. cholerae cases were detected at any site during the winter months of July through October. Counts were detectable in the environment before onset of cholera in the community, with counts at “cleaner” sites upriver correlating significantly with occurrence of community disease 2 and 3 months later. In sites with heavy sewage contamination, V. cholerae could still be detected before the onset of cases in the community; however, in contrast to upriver sites, counts at these latter sites correlated most closely with the number of concurrently occurring cholera cases. These data support a model of cholera seasonality in which initial increases in number of V. cholerae in the environment (possibly triggered by temperature) are followed by onset of illness in the community, with these human cases further amplifying the organism as the epidemic cycle proceeds. Am J Epidemiol 1997;146: 1067–75. -
PublicaciónChronic Pain Estimation Through Deep Facial Descriptors Analysis(Springer, 2020)
;Mauricio A. ;Peña J. ;Dianderas E. ;Mauricio L. ;Díaz J.Morán A.Worldwide, chronic pain has established as one of the foremost medical issues due to its 35% of comorbidity with depression and many other psychological problems. Traditionally, self-report (VAS scale) or physicist inspection (OPI scale) perform the pain assessment; nonetheless, both methods do not usually coincide [14]. Regarding self-assessment, several patients are not able to complete it objectively, like young children or patients with limited expression abilities. The lack of objectivity in the metrics draws the main problem of the clinical analysis of pain. In response, various efforts have tried concerning the inclusion of objective metrics, among which stand out the Prkachin and Solomon Pain Intensity (PSPI) metric defined by face appearance [5]. This work presents an in-depth learning approach to pain recognition considering deep facial representations and sequence analysis. Contrasting current state-of-the-art deep learning techniques, we correct rigid deformations caught since registration. A preprocessing stage is applied, which includes facial frontalization to untangle facial representations from non-affine transformations, perspective deformations, and outside noises passed since registration. After dealing with unbalanced data, we fine-tune a CNN from a pre-trained model to extract facial features, and then a multilayer RNN exploits temporal relation between video frames. As a result, we overcome state-of-the-art in terms of average accuracy at frames level (80.44%) and sequence level (84.54%) in the UNBC-McMaster Shoulder Pain Expression Archive Database. -
PublicaciónCleavage and development in cultured preimplantation mouse embryos exposed to lidocaine(Elsevier, 1996)
;Del Valle L.J.Orihuela P.A.Two-cell preimplantation mouse embryos were exposed in vitro to lidocaine (0 to 1,000 μg/mL) for 72 h to determine the effects of this anesthetic on subsequent cleavage and development during prolonged exposures. Embryonic development was monitored each 24 h for 3 d. Lidocaine adversely affected the in vitro development of the mouse embryos, altering the distribution of the development stages at the evaluated culture tunes.