Eloy Alfaro, Ecuador

National University of Chimborazo

Eloy Alfaro, Ecuador

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Ramos P.R.H.,National University of Chimborazo | Penalvo F.J.G.,University of Salamanca | Gonzalez M.A.C.,University of León
ACM International Conference Proceeding Series | Year: 2014

The popularization of mobile devices worldwide and their constant improvement in communicability, portability, navigation and content creation, opens up many possibilities for integration in the learning process. On the other hand the new educational approaches that focus on the student, promoted through the Personal Learning Environments (PLE) show evidence that it can be done successfully in most cases studied. However, these educational innovations have not yet been implemented in some Latin American countries, so the present research searches to introduce the PLE approach in Ecuadorian university, taking advantage of the functionalities offered by mobile devices not only for leisure but for learning activities in informal environments and which are recognized and valued in the academy. Similarly it is intended that students identify with these new Mobile Personal Learning Environments as ecosystems of lifelong learning.

Pomboza-Junez W.G.,National University of Chimborazo | Holgado-Terriza J.A.,University of Granada
ACM International Conference Proceeding Series | Year: 2016

Human-machine interaction requires the proposal of new systems, which can be adapted to the needs of the user at any time. This paper proposes the use of natural user interface as an alternative to the traditional contact-based Graphical User Interface. This new interface does not require touching the surface of the device, and thus provides touch-free management of applications in mobile devices. This paper will show the simplicity and efficacy of a natural user interface, in comparison to a Graphical User Interface alternative. © 2016 ACM.

Pappalardo S.E.,University of Padua | De Marchi M.,University of Padua | De Marchi M.,National University of Chimborazo | Ferrarese F.,University of Padua
PLoS ONE | Year: 2013

The Tagaeri Taromenane People are two indigenous groups belonging to the Waorani first nation living in voluntary isolation within the Napo region of the western Amazon rainforest. To protect their territory the Ecuadorean State has declared and geographically defined, by Decrees, the Zona Intangible Tagaeri Taromenane (ZITT). This zone is located within the UNESCO Yasuní Biosphere Reserve (1989), one of the most biodiverse areas in the world. Due to several hydrocarbon reserve exploitation projects running in the area and the advancing of a large-scale deforestation front, the survival of these groups is presently at risk. The general aim was to validate the ZITT boundary using the geographical references included in the Decree 2187 (2007) by analyzing the geomorphological characteristics of the area. Remote sensing data such as Digital Elevation Models (DEM), Landsat imagery, topographic cartography of IGM-Ecuador, and fieldwork geographical data have been integrated and processed by Geographical Information System (GIS). The ZITT presents two levels of geographic inconsistencies. The first dimension is about the serious cartographical weaknesses in the perimeter delimitation related to the impossibility of linking two rivers belonging to different basins while the second deals with the perimeter line not respecting the hydrographic network. The GIS analysis results clearly show that ZITT boundary is cartographically nonsense due to the impossibility of mapping out the perimeter. Furthermore, GIS analysis of anthropological data shows presence of Tagaeri Taromenane clans outside the ZITT perimeter, within oil production areas and in nearby farmer settlements, reflecting the limits of protection policies for non-contacted indigenous territory. The delimitation of the ZITT followed a traditional pattern of geometric boundary not taking into account the nomadic characteristic of Tagaeri Taromenane: it is necessary to adopt geographical approaches to recognize the indigenous right to their liveable territories in the complex territorialities enacted by different stakeholders. © 2013 Pappalardo et al.

Gonzalez-Castro A.,CSIC - Institute of Natural Products and Agrobiology | Gonzalez-Castro A.,National University of Chimborazo | Calvino-Cancela M.,University of Vigo | Nogales M.,CSIC - Institute of Natural Products and Agrobiology
Ecology | Year: 2015

Seed dispersal effectiveness (SDE) is the contribution of dispersers to plant recruitment and is estimated as the product of the number of seeds dispersed (quantity) and the probability of recruitment of each dispersed seed (quality). Although SDE is a key concept in seed dispersal ecology, few studies estimate SDE and none has a community approach. Oceanic islands, with simple communities, are ideal for this purpose. In this study, we compared the SDE of the main types of dispersers (lizards and passerine birds) at the community level in a given habitat. We estimated SDE using a stochastic simulation model parameterized with empirical data on quantity and quality components measured throughout the recruitment process. Although lizards are highly frugivorous and their density was ~20 times higher than that of birds, lizards and birds dispersed a similar quantity of seeds. This may be due to lower intake of seeds by lizards due to their slower metabolism (~20 times lower than birds). This low metabolic rate limits the importance of lizards as seed dispersers, but it is compensated by extraordinarily high lizard densities in the study area (~9600 individuals/km2). High densities of lizards are typical of islands, and this helps to explain why dispersal by lizards seems mainly an island phenomenon. Birds and lizards showed functional complementarity, especially regarding seed dispersal distribution patterns. In fact, lizards dispersed more seeds in shrublands and open sites, and birds in woodlands and beneath canopies, with their joint contribution helping to maximize recruitment. Lizards provided higher SDE than birds for 7 out of 11 plant species. The disperser with a higher quantity for a given plant generally had the higher quality, and plants could be classified as bird- or lizarddependent for dispersal. This dependence increased when considering SDE instead of dispersal quantity only. Moreover, quality was a better predictor of SDE than quantity, which should be considered when parameterizing interaction networks, as this might affect inferences about their architecture. © 2015 by the Ecological Society of America.

Usachev B.I.,National University of Chimborazo
Journal of Fluorine Chemistry | Year: 2015

This review describes synthetic methods for the preparation of such advanced conjugated cyclic dienes and electrophiles as 6-CF3-2-pyrones (6-(trifluoromethyl)-2H-pyran-2-ones), their versatile chemical properties and use in the syntheses of various CF3-containing cycloadducts, highly functionalized trifluoromethylated aromatic and heteroaromatic compounds. Synthesis of 6-CF3-2-pyrones bearing a substituent (substituents) at position(s) 3, 4 and 5, regio- and stereoselective preparation of trifluoromethylated cycloadducts (and their derivatives) via Diels-Alder reactions (and retro hetero-Diels-Alder reaction) from these pyrones and compounds containing in their molecules a reactive double (triple) bond, as well as reactions with nucleophiles has been presented in the review. Due to the presence of the electron-withdrawing trifluoromethyl group and the diene moiety, 6-CF3-2-pyrones are highly reactive substrates towards both dienophiles and nucleophiles. High regio- and stereoselectivity of the reactions allows the use of these excellent CF3-containing building-blocks for the preparation of various bicyclic, aromatic and heteroaromatic compounds, important starting substrates in biological or medicinal chemistry and related areas. © 2015 Elsevier B.V. All rights reserved.

This review describes synthetic methods for the preparation of such modern and versatile building-blocks as 2-CF3-4-pyrones (2-(trifluoromethyl)-4H-pyran-4-ones), and their use in regioselective syntheses of various CF3-containing compounds. Synthesis of 2-CF3-4-pyrones bearing a substituent (substituents) at position(s) 3, 5 and 6, as well as regioselective preparation of trifluoromethylated 4(1H)-pyridin-4-one, benzo[c][1,6]naphthyridine, 4-thiopyrone, 2-quinaxolinone, diazepine, benzo[b][1,4]oxazin-2-one, pyrazole, 3-(pyrazolyl)indlole, pyrazolo[1,5-c]pyrimidine derivatives on the basis of these building-blocks has been described. The closest analogs of 2-CF3-4-pyrones, 2-RF-4-pyrones (RF = CF2H, C2F4H, C3F7, C4F9, C6F13, CF2CFCl2, CF2CHFCF3) has also been presented in the review. Due to unique regioselectivity, a strong regio-sensitivity to solvents and availability, 2-CF3-4-pyrones can be attributed to excellent starting or intermediate substrates for the preparation of various trifluoromethylated compounds. In contrast to other 2-RF-4-pyrones, 2-CF3-4-pyrones are more synthetically available and interact with nucleophiles usually more selectively. ©2015 Elsevier B.V.All rights reserved.

Synthesis, significance and potential applications of such medicinally and biologically beneficial compounds as fluoroalkylated at the pyrrole moiety indoles (1-/2-/3-fluoroalkyl-substituted indoles) are described. Having various bioactive properties, RF-indoles are promising medicinally and biologically beneficial compounds. At present, known synthetic routes for the preparation of RF-indoles affect a fairly wide variety of advanced methods. These important substances can be synthesized either via direct fluoroalkylation or via procedures involving transformations of fluoroalkylated building-blocks. In direct fluoroalkylation (trifluoromethylation), indole and its derivatives were used in the reactions with such fluoroalkylating agents as fluoroalkyl halides, CF3CO2Na (in the presence of CuI), Ruppert-Prakash reagent (a Pd-catalyzed trifluoromethylation), CuI/FO2SCF2CO2Me. 2-CF3-4-pyrones can be used as trifluoromethylated building blocks for regioselective syntheses of CF3-indoles. Cyclizations of some RF-bearing ortho-disubstituted benzene derivatives allow preparation of various RF-indoles. Reactivity of the trifluoromethyl group and indole moiety of CF3-indoles is considered. © 2016 Elsevier B.V. All rights reserved.

Olivito R.S.,University of Calabria | Cevallos O.A.,University of Calabria | Cevallos O.A.,National University of Chimborazo | Carrozzini A.,University of Calabria
Materials and Design | Year: 2014

Natural fibres are one of the most studied materials. However, the use of these fibres as reinforcements in composite materials for structural applications, especially for existing or historical masonry structures, remains a challenge. In this study, efforts were made to develop sustainable composites using cementitious matrices reinforced with untreated bi-directional fabrics of natural fibres, namely, flax and sisal fibres. The fibres were mechanically characterised by tensile tests performed on both single yarns and fabric strips. Ageing effects due to fibre mineralisation in alkaline cement paste environments may cause a reduction in the tensile strength of natural fibres. The matrices used to study fibre durability were a natural hydraulic lime-based mortar (NLM) mix with a low content of water-soluble salts and a lime-based grouting (NLG) mix containing natural pozzolans and carbonated filler. Tensile tests on impregnated single yarns subjected to wetting and drying cycles by exposure to external weathering were conducted at different ages to quantify these problems. Composite specimens were manufactured by the hand lay-up moulding technique using untreated fibre strips and an NLG matrix. The mechanical response of natural fibre reinforced cementitious (NFRC) composites was measured under tension, and the effect of the matrix thickness was also addressed. Both sisal and flax fibres showed good adhesion with the NLG matrix, making them capable of producing composites with ductile behaviour and suitable mechanical performance for strengthening applications in masonry structures. © 2013 Elsevier Ltd.

Cevallos O.A.,University of Calabria | Cevallos O.A.,National University of Chimborazo | Olivito R.S.,University of Calabria
Composites Part B: Engineering | Year: 2014

The mechanical behaviour of fabric-reinforced composites can be affected by several parameters, such as the properties of fabrics and matrix, the fibre content, the bond interphase and the anchorage ability of fabrics. In this study, the effects of the fibre type, the fabric geometry, the physical and mechanical properties of fabrics and the volume fraction of fibres on the tensile stress-strain response and crack propagation of cementitious composites reinforced with natural fabrics were studied. To further examine the properties of the fibres, mineral fibres (glass) were also used to study the tensile behaviour of glass fabric-reinforced composites and contrast the results with those obtained for the natural fabric-reinforced composites. Composite samples were manufactured by the hand lay-up moulding technique using one, two and three layers of flax and sisal fabric strips and a natural hydraulic lime (NHL) grouting mix. Considering fabric geometry and physical properties such as the mass per unit area and the linear density, the flax fabric provided better anchorage development than the sisal and glass fabrics in the cement-based composites. The fabric geometry and the volume fraction of fibres were the parameters that had the greatest effects on the tensile behaviour of these composite systems. © 2014 Elsevier Ltd. All rights reserved.

Llorca C.B.D.,National University of Chimborazo
Fronteiras | Year: 2015

The case method in management science is derived from the author's research work both in conducting business operations and in developing cases for use in class and methodological deployment item required in solving the case. Similarly, the experiences are part of the analysis of cases in the group of the subject and validation of cases by participants in a given program. The aim of this work is to strengthen the knowledge of what is the case, how they are made and how to use in the teaching process.

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