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Recomendaciones técnicas para la migración a DSpace 7
Get PDFRevisa las nuevas funcionalidades que tiene DSpace 7 así como la tecnología y estándares internacionales sobre el tema, además abordará aspectos sobre la actualización de paquetería, tips para hacer una actualización, recomendaciones en sistemas operativos
A contemporary approach to the MSE paradigm powered by Artificial Intelligence from a review focused on Polymer Matrix Composites
No full textThis paper was written in the context of the project: Desarrollo de un software para predecir el desempe no structural de product terminado en el proceso de fabricacion por manufactura aditiva de materiales compuestos founded by Cienciactiva, CONCYTEC, under the contract number No 112-2018-FONDECYT-BM-IADT-MU. The authors of this manuscript appreciate the financial support from the Peruvian Government.Artificial Intelligence (AI) is a broad discipline that uses powerful algorithms to emulate important aspects of human intelligence. Provided by the Industry 4.0 revolution, AI is increasingly applied in different fields from research to production. One of these fields is Materials Science and Engineering (MSE) which studies the relationships between processing, structure, properties, and performance of materials. The application of AI to MSE has triggered the invention of new materials to satisfy the demanding requirements in myriad sectors through the years. In this context, the MSE paradigm emerged as a framework to define these relationships supported by the available technologies at the corresponding time. This is how Polymer Matrix Composites (PMC) were synthesized. During the last years, they have turned from a futuristic solution to a necessity due to the wide range of advantages they offer concerning other conventional materials. The present work presents a modified approach to the MSE paradigm with the application of AI algorithms. An overview of the research advances from 2003 to 2019 in each fundamental link of the proposed MSE paradigm for PMC is exhibited in an organized fashion. This article must serve engineers and scientists working at the intersection of mechanical engineering, materials science and computer science to identify trendy topics in these fields. It aims to represent a starting point for developing innovative methods and proposing new research topics in the framework of the MSE paradigm powered by AI for PMC.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Molecular interaction of natural dye based on Zea mays and Bixa orellana with nanocrystalline TiO2 in dye sensitized solar cells
Get PDFThis work studies the interaction between natural dyes obtained from Peruvian Zea mays and Bixa orellana seeds and nanostructured titanium dioxide, in order to evaluate their function as sensitizers into solar cell devices. The effective attachment of dyes to the TiO2 layer is corroborated by the comparison of UV-Visible absorption and FT-IR spectra of the extracted dye solutions and sensitized TiO2 electrodes. The principal compounds from the seed extraction of Zea mays and Bixa orellana are cyanidin-3-glucoside (C3G) and bixin respectively, which were analyzed in an isolated dye/cluster TiO2 system by molecular dynamic simulation. The results showed that chemisorption is carried out through a consecutive deprotonation process, and Ti-O bond formation by the monodentate OH and COOH anchoring groups, for C3G and bixin respectively. Finally, we tested the effect of the dye - TiO2 interaction on the charge transfer by the comparison of the current-voltage curves and incident photon-to-current conversion efficiency (IPCE) of the cells. We found that dye agglomeration in films with Bixa orellana and high charge recombination of films with Zea mays are critical points to be solved. For this reason, we propose the pretreatment of the TiO2 film before sensitization with Bixa orellana and analyze the effects of pH in Zea mays solution, in order to obtain better device efficiencies.The authors gratefully acknowledge support from the PhD program in Physics of the National University of Engineering funded through Resolution No. 168-2015-FONDECYT and the equipment project financed through Resolution No. 008-2018-FONDECYT-BM
Natural Occurrence of Mycotoxin-Producing Fusaria in Market-Bought Peruvian Cereals: A Food Safety Threat for Andean Populations
No full textThis research was funded by the French National Alliance for Life Sciences and Health, grant number ENV201408. S.B. has received funding from the European Union's Horizon 2020 Framework program under the Marie Sklodowska-Curie Actions, agreement number 823935. P.V.O. was supported by a postdoctoral fellowship from the French National Research Institute for Sustainable Development (IRD) (04077858). JPC was a recipient of a doctoral fellowship from the Peruvian National Council for Science and Technology (212-2015-FONDECYT).Consumption of cereals contaminated by mycotoxins poses health risks. For instance, Fumonisins B, mainly produced by Fusarium verticillioides and Fusarium proliferatum, and the type B trichothecene deoxynivalenol, typically produced by Fusarium graminearum, are highly prevalent on cereal grains that are staples of many cultural diets and known to represent a toxic risk hazard. In Peru, corn and other cereals are frequently consumed on a daily basis under various forms, the majority of food grains being sold through traditional markets for direct consumption. Here, we surveyed mycotoxin contents of market-bought grain samples in order to assess the threat these mycotoxins might represent to Peruvian population, with a focus on corn. We found that nearly one sample of Peruvian corn out of six was contaminated with very high levels of Fumonisins, levels mostly ascribed to the presence of F. verticillioides. Extensive profiling of Peruvian corn kernels for fungal contaminants could provide elements to refine the potential risk associated with Fusarium toxins and help define adapted food safety standards.Fondo Nacional de Desarrollo Científico y Tecnológico - Fondecy
A qualitative and quantitative comparison between Web scraping and API methods for Twitter credibility analysis
No full textThis research was supported by the FONDO NACIONAL DE DESARROLLO CIENTÍFICO, TECNOLÓGICO Y DE INNOVACIÓN TECNOLÓGICA – FONDECYT as executing entity of CONCYTEC under grant agreement no. 01–2019-FONDECYT-BM-INC.INV in the project RUTAS: Robots para centros Urbanos Turísticos Autónomos y basados en Semántica.Purpose: This paper aims to perform an exhaustive revision of relevant and recent related studies, which reveals that both extraction methods are currently used to analyze credibility on Twitter. Thus, there is clear evidence of the need of having different options to extract different data for this purpose. Nevertheless, none of these studies perform a comparative evaluation of both extraction techniques. Moreover, the authors extend a previous comparison, which uses a recent developed framework that offers both alternates of data extraction and implements a previously proposed credibility model, by adding a qualitative evaluation and a Twitter-Application Programming Interface (API) performance analysis from different locations. Design/methodology/approach: As one of the most popular social platforms, Twitter has been the focus of recent research aimed at analyzing the credibility of the shared information. To do so, several proposals use either Twitter API or Web scraping to extract the data to perform the analysis. Qualitative and quantitative evaluations are performed to discover the advantages and disadvantages of both extraction methods. Findings: The study demonstrates the differences in terms of accuracy and efficiency of both extraction methods and gives relevance to much more problems related to this area to pursue true transparency and legitimacy of information on the Web. Originality/value: Results report that some Twitter attributes cannot be retrieved by Web scraping. Both methods produce identical credibility values when a robust normalization process is applied to the text (i.e. tweet). Moreover, concerning the time performance, Web scraping is faster than Twitter API and it is more flexible in terms of obtaining data; however, Web scraping is very sensitive to website changes. Additionally, the response time of the Twitter API is proportional to the distance from the central server at San Francisco. © 2021, Emerald Publishing Limited.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Evolution of antimicrobial resistance levels of eskape microorganisms in a peruvian iv-level hospital
No full textJR was supported by Fondo Nacional de Desarrollo Científico, Tecnológico y de Innovación Tecnológica (FONDECYT - Perú) within the “Proyecto de Mejoramiento y Ampliación de los Servicios del Sistema Nacional de Ciencia, Tecnología e Innovación Tecnológica" [contract: 08-2019-FONDECYT-BM-INC-INV"].Backgound: The members of the so-called ESKAPE group (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp.) are a frequent cause of severe infection, ranking among the most relevant causes of hospital infections. In Peru, few studies, often focused in a single ESKAPE microorganism, have been performed, but none providing an overall and comprehensive long-time analysis of the antibiotic resistance of ESKAPE microorganisms. In the present study, the evolution of antimicrobial resistance levels of ESKAPE microorganisms isolated during 2009 - 2010 (Period 1) and 2012 - 2014 (Period 2) in a IV-level hospital in Lima was analyzed. Materials and Methods: ESKAPE microorganisms were isolated from inpatients clinical samples. Bacterial identification, as well as antimicrobial susceptibility levels for up to 29 antimicrobial agents and presence of Extended-Spectrum ?-Lactamases (only established in K. pneumoniae) were determined using automatic methods. Results: Of 9,918 clinical isolates, 1,917/3,777 (50.8%) [JAN/2009-JUN/2010 (Period 1)] and 4764/6141 (46.4%) [JAN/2012-DEC/2014 (Period 2)] belonged to the ESKAPE group (P <0.0001). ESKAPE were more frequent in the intensive care unit (ICU) (P <0.0001). E. faecium decreased from 5.1% to 4.1% (P <0.5), S. aureus from 10.5% to 7.0% (P <0.05), and P. aeruginosa from 12.9% to 11.6% (P <0.05), while, A. baumannii increased from 5.0% to 6.7% (P <0.05), mainly related to an increase in ICU isolates (8.4% vs. 17.1%; P <0.05). Overall, high levels of antimicrobial resistance were detected, but with few exceptions (e.g. vancomycin in E. faecium), antibiotic resistance levels remained stable or lower in Period 2. Contrarily, A. baumannii showed significantly increased resistance to different cephalosporins, carbapenems and amoxicillin plus sulbactam. Conclusion: The introduction of a successful extensively drug-resistant A. baumannii clone in the ICU is suspected. The isolation of ESKAPE and levels of antibiotic resistance levels have reduced over time. © 2021 by The Korean Society of Infectious Diseases.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Gas phase proton affinity and basicity of methylated uracil-derivatives
No full textJRBL acknowledges the support from the Peruvian funding agencies OGI-VRI-UNI ( Oficina de Gestión de Investigación-Vicerrectorado de Investigación U.N.I. ) and CONCYTEC-Master scholarship grant N° 167-2015-FONDECYT-UNI.The gas phase proton affinity (PA) and basicity (GB) of methylated uracil derivatives have been evaluated experimentally by the Extended Kinetic Method (EKM) using ESI-TQ mass spectrometry. The experimental PA values, in kJ·mol-1, for 1,5-dimethyluracil (890.0 ± 8.4), 5,6-dimethyluracil (896.4 ± 8.4) and 5,6-dihydro-6-methyluracil (856.0 ± 8.4) were in the same order as those determined theoretically by calculations performed at the B3LYP/6–311++G(3df,2p) level of theory. From the results, it can be concluded that most stable protonated tautomers correspond to the enol structures. Furthermore, it should be noted that the methylation of uracil and 5,6-dihydrouracil has little effect on the proton affinity and basicity of their corresponding methylated derivatives.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Isolated and Bidirectional two-stage DC/AC converter with grid-forming virtual inertia and high ripple on the DC bus for Single-Phase Grid applications
No full textACKNOWLEDGMENT This work was financed by CONCYTEC-FONDECYT within the call for projects E041-01 [Contract Number 031-2019]The increasing utilization of electronic converters to interface distributed energy resources (energy storage units and renewable energies) with the grid, has decreased the inertial spinning reserves of the power system. In this context, an isolated and bidirectional two-stage DC-AC converter with grid-forming virtual inertia capability and film capacitor on the DC-Link is presented. The proposed converter allows to interface energy storage units (ESU) with the single-phase grid. The two-stage DC-AC converter is composed of a dual active bridge series resonant (DABSR) DC-DC converter cascaded with a single-phase voltage source inverter (VSI), linked by a film capacitor. In the proposed control strategy, the DABSR controls the DC-Link voltage allowing the power decoupling on the DC-side while the VSI is controlled to emulate a virtual synchronous machine (VSM) when the ESU are connected to the grid. Therefore, the proposed converter has the following advantages: (1) high durability with reduced volume due to film capacitor instead of electrolytic capacitor on the DC-Bus, (2) high efficiency due to ZVS in the DC-DC converter and, (3) virtual inertia provided by VSI controlled as a VSM, increasing inertial energy reserves in the grid. The converter functionality and control strategy are validated by simulation of a 3.3kW system. © 2021 IEEE.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Properties of fractional operators with fixed memory length
No full textCésar T. Ledesma and Josias V. Baca were partially supported by CONCYTEC, Peru, 379-2019-FONDECYT “ASPECTOS CUALITATIVOS DE ECUACIONES NO-LOCALES Y APLICACIONES.”In this present paper, we discuss some properties of fractional operators with fixed memory length (Riemann–Liouville fractional integral, Riemann–Liouville and Caputo fractional derivatives). Some observations and examples are discussed during the article, in order to make the results well defined and clear. Furthermore, we consider the fundamental theorem of calculus for fractional operators with fixed memory length. © 2021 John Wiley & Sons, Ltd.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Unsupervised detection of disturbances in 2D radiographs
No full textThis work was supported by grant 234-2015-FONDECYT (Master Program) from Cienciactiva of CONCYTEC-PERU and German BMBF research campus MODAL (grant no. 3FO18501). The authors thank CiTeSoft-UNSA for the database access. The authors report no conflicts of interest.We present a method based on a generative model for detection of disturbances such as prosthesis, screws, zippers, and metals in 2D radiographs. The generative model is trained in an unsupervised fashion using clinical radiographs as well as simulated data, none of which contain disturbances. Our approach employs a latent space consistency loss which has the benefit of identifying similarities, and is enforced to reconstruct X-rays without disturbances. In order to detect images with disturbances, an anomaly score is computed also employing the Frechet distance between the input X-ray and the reconstructed one using our generative model. Validation was performed using clinical pelvis radiographs. We achieved an AUC of 0.77 and 0.83 with clinical and synthetic data, respectively. The results demonstrated a good accuracy of our method for detecting outliers as well as the advantage of utilizing synthetic data.Fondo Nacional de Desarrollo Científico y Tecnológico - Fondecy