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Havana, Cuba

The University of Cienfuegos "Carlos Rafael Rodríguez" is a university located in Cienfuegos, Cuba. Wikipedia.

Alvarez-Betancourt Y.,University of Cienfuegos | Garcia-Silvente M.,University of Granada

Person identification based on iris recognition is getting more and more attention among the modalities used for biometric recognition. This fact is due to the immutable and unique characteristics of the iris. Therefore it is of utmost importance for researchers interested in this discipline to know who and what is relevant in this area. This paper presents a comprehensive overview of the field of iris recognition research using a bibliometric approach. Besides, this article provides historical records, basic concepts, current progress and trends in the field. With this purpose in mind, our bibliometric study is based on 1,354 documents written in English, published between 2000 and 2012. Scopus was used to perform the information retrieval. In the course of this study, we synthesized significant bibliometric indicators on iris recognition research in order to evaluate to what extent this particular field has been explored. Thereby, we focus on foundations, temporal evolution, leading authors, most cited papers, significant conventions, leading journals, outstanding research topics and enterprises and patents. Research topics are classified into three main categories: ongoing, emerging, and decreasing according to their corresponding number of publications over the period under study. An analysis of these indicators suggests there has been major advances in iris recognition research and also reveals promising new avenues worthy of investigation in the future. This study will be useful to future investigators in the field. © 2014, Akadémiai Kiadó, Budapest, Hungary. Source

Leon G.,Pontifical Catholic University of Valparaiso | Roque A.A.,University of Cienfuegos
Journal of Cosmology and Astroparticle Physics

In this paper we investigate, from the dynamical systems perspective, the evolution of a Kantowski-Sachs metric in a generic class of f(R) models. We present conditions (i.e., differentiability conditions, existence of minima, monotony intervals, etc.) for a free input function related to the f(R), that guarantee the asymptotic stability of well-motivated physical solutions, specially, self-accelerated solutions, allowing to describe both inflationary- and late-time acceleration stages of the cosmic evolution. We discuss which f(R) theories allows for a cosmic evolution with an acceptable matter era, in correspondence to the modern cosmological paradigm. We find a very rich behavior, and amongst others the universe can result in isotropized solutions with observables in agreement with observations, such as de Sitter, quintessence-like, or phantom solutions. Additionally, we find that a cosmological bounce and turnaround are realized in a part of the parameter-space as a consequence of the metric choice. © 2014 IOP Publishing Ltd and Sissa Medialab srl. Source

Gutierrez A.S.,University of Cienfuegos | Vandecasteele C.,Catholic University of Leuven

A new way to evaluate the energetic performance of lime shaft kilns is proposed. Two new exergy-based indicators are introduced for the evaluation, one to assess the exergy efficiency of limekilns and the other indicator to assess the effectiveness of the exergy consumption of the dissociation reaction. The combination of both indicators provides a clear picture of the energetic performance of the process, highlighting the main potentialities for fuel saving (fuel consumption represents about 50% of total production costs).The validity of the proposed assessment is examined using some operating data measured in a commercial lime factory. Results show that introduction of exergy-based indicators in the assessment improves the evaluation of the energy consumption of the calcination process. In this way the impact of the process losses in the fuel consumption is better addressed. © 2011 Elsevier Ltd. Source

Piedra O.P.F.,University of Cienfuegos | De Oliveira J.,University of Sao Paulo
International Journal of Modern Physics D

We investigate the influence of vacuum polarization of quantum massive fields on the scalar sector of quasinormal modes in spherically symmetric black holes. We consider the evolution of a massless scalar field on the spacetime corresponding to a charged semiclassical black hole, consisting of the quantum-corrected geometry of a ReissnerNordström black hole dressed by a quantum massive scalar field in the large mass limit. Using a sixth order WKB approach we find a shift in the quasinormal mode frequencies due to vacuum polarization. © 2010 World Scientific Publishing Company. Source

The reproduction of the peasantry, as a family-economic unit and social class, has become a global concern. The food emergency and the need for sustainable forms of production have pushed up the family farming as an alternative solution; for this reason, the scientific activity invests in studying the diversity of family forms and changes in livelihood strategies and social reproduction. The article presented is a review about the factors involved in the reproduction of the peasantry in Cuba, result of theoretical reconstruction achieved from the sociology of knowledge. This theoretical and methodological perspective establishes the dialectical relationship between scientific knowledge that has occurred, and the social context of reference; also describes the context of implementation of economic policies and social transformations that reflects the science about the countryside. The main result lies in determining the forms of manifestation of economic, cultural and social capital, which is the result of data's interpretation using content analysis and that support from a socio-historical perspective, understanding the peasantry and their reproduction, as a case study for science in Cuba. Source

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