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Search Results: 1 - 10 of 219738 matches for " Cristina Alonso-Tristán "
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Performance Indicators for Sun-Tracking Systems: A Case Study in Spain  [PDF]
Miguel de Simón-Martín, Cristina Alonso-Tristán, Montserrat Díez-Mediavilla
Energy and Power Engineering (EPE) , 2014, DOI: 10.4236/epe.2014.69025
Abstract: Current PV cells technology takes advantage mainly from beam radiation. In this context the sun-trackers are such devices for efficiency improvement. On the other hand, projected shadows between devices make mandatory to increase the distances between mounting systems. Thus, the land’s capacity for mounting PV panels can be dramatically decreased. This fact conducts us to wonder where the optimum efficient point is. First, in this paper different types of sun-tracking systems are classified according to the movement they perform (cinematic classification). Further, three real PV installations-fixed, horizontal-axis tracking and dual-axis mount tracking—located in the same geographical area in Spain (they are approximately under the same weather conditions) are analyzed. These installations have been studied in order to establish which one is the most efficient and affordable—Specific Energy Production (SEP) and Performance Ratio (PR) analysis. PVGIS solar radiation estimate tool has been used for comparing the theoretical radiation potential on each plant. The land requirements have been considered in the analysis of the Ground Cover Ratio (GCR) and the Surface Performance Ratio (SPR). Moreover, comparing three main financial indicators let us carry out a financial study: Payback Time (PBT), Net Present Value (NPV) and Internal Rate of Return (IRR). In the case study, final annual energetic results demonstrate that the dual-axis plant shows a relevant SEP advantage, but if we take into account the land occupied for this sort of devices we find much more profitable the horizontal-axis sun-tracking system, with a SPR value 4.24% higher than the fixed system we have studied. Its PBT is also a 22% lower than the dual-axis tracking installation.
Diagnóstico de la hemorragia subaracnoidea espontánea de escasa cuantía o de larga evolución: a propósito de un caso
Alonso Formento,E.; Rodero álvarez,F.; Ros Tristán,C. M.; Calpe Gil,M. J.; Martínez Oviedo,A.;
Anales de Medicina Interna , 2008, DOI: 10.4321/S0212-71992008000700008
Abstract: subarachnoid hemorrhage implies the presence of blood within the subarachnoid space from some pathologic process. the initial study of choice is an urgent cranial computed tomography scan, but its sensitivity declines with time. so that it is recommended that patients with severe sudden headache but normal cranial computed tomography scan, should have a lumbar puncture performed, more than 12 hours after the onset of symptoms, to rule out subarachnoid hemorrhage. the methods for distinguishing among traumatic lumbar puncture and true subarachnoid hemorrhage include the erythrocyte level, the "three tube test", d-dimer assay and ferritin in cerebrospinal fluid. but the best technique is the xanthochromia o yellow-to-orange cerebrospinal fluid supernatant, measured spectrographically. we report a case of a young woman with a subarachnoid hemorrhage diagnosed by xanthochromia after 18 days after the onset of bleeding.
sociedades cientificas de estudiantes de medicina: el futuro de la investigacion de Latinoamérica
Percy Mayta Tristán
MedUNAB , 2010,
Abstract: En Latinoamérica, desde hace más de 25 a os se reúnen los estudiantes de medicina de diferentes países para presentar sus trabajos de investigación en Congresos Científicos Internacionales Organizados por la Federación Latinoamericana de Sociedades Científicas de Etudiantes de Medicina (FELSOCEM); así mismo, en cada país existen organizaciones nacionales y locales que realizan eventos similares, que en el caso de colombia, son organizados por la Asociación de Sociedades Científicas de Estudiantes de Medicina de Colombia (ASCEMCOL), siendo este a o realizado por la Universidad Autónoma de Bucaramanga.
Rese a de "Contemporánea. Historia y problemas del siglo XX"
Eduardo Rey Tristán
Tzintzun. Revista de Estudios Históricos , 2011,
Abstract:
Models of body and femininity in a local gym Modelos de cuerpo y feminidad en un gimnasio local
Bianca Tristán
Anthropologica , 2011,
Abstract: The purpose of this work is to explore the ideals of body and behavior among adult women of our new Peruvian middle class attending a gym. It suggests that the ideals of bodies developed in this place are in closely related to traditional notions of gender roles of our society. But, at the same time, emphasizes the fact that they, not only try to have a body in accordance to social expectation, but also to interact or make friends, and to experience a variety of emotions in performing aerobic activity itself. Finally, the paper explores the meaning that these women give to their experience at the gym. Not only does this experience get them closer to the ideal body, fixed by the social standards of femininity, but the experience turns into an opportunity to discuss and remake those models of femininity, and assert their own discourses of identity. Este trabajo explora los ideales de cuerpo y comportamiento femenino presentes en mujeres adultas de nuestra nueva clase media , que asisten a un gimnasio local o de barrio. Propone que los ideales de cuerpo desarrollados por las alumnas están íntimamente relacionados con tradicionales nociones de roles de género de nuestra sociedad; pero, a su vez, enfatiza el hecho de que ellas, además de buscar alcanzar un cuerpo acorde a las expectativas sociales, también buscan interactuar y/o hacer amistad entre ellas, así como experimentar goce u otras emociones extraordinarias en la realización de la actividad aeróbica en sí, etcétera. De esta forma, el texto explora finalmente cómo el significado que estas mujeres otorgan a su vivencia en el gimnasio no solo no las acerca necesariamente al cuerpo ideal que calza con el estándar social de feminidad, sino que incluso su experiencia se convierte en una oportunidad para discutir y reelaborar los modelos de feminidad en sí mismos y afirmar sus propias narrativas de identidad.
El proceso de publicación y evaluación de los manuscritos en CIMEL
Percy Mayta Tristán
CIMEL. Ciencia e Investigación Médica Estudiantil Latinoamericana , 2003,
Abstract:
Association between the acquisition of influenza-like illness and the frequent use of public transport
Daniel Yumpo-Cárdenas, Rosalie López-Otárola, José Carlos Rodríguez-Abt, Pamela ávila-Espinoza, Grecia Lizzetti-Mendoza, Alonso Natividad-Nú?ez, Percy Mayta-Tristán
Revista Médica de Risaralda , 2012,
Abstract: Background: Public transport in big cities like Lima may favor the spread of air-borne diseases due to overcrowding, poor ventilation and a prolonged stay in confined spaces. Material and methods: We performed a cross-sectional study in 592 students from a private university in Lima to evaluate the relationship between the frequent use of public transport and the presence of influenza-like illness (ILI). Self-report of ILI was defined as fever plus cough or sore throat in last two weeks, most used type of transport to go to university. OR crude and adjusted were calculated used simple and multiple logistic regression. Results: 12.0% (71/592) had ILI in the past two weeks. Use of public transport (OR = 3.6; 95% CI 1.2 to 10.2) and have contact with someone with ILI at home (OR = 1.8; 95% CI 1.1 to 3.1) were found associated in multiple logistic regression model. No association with age, vaccination against influenza, living with children, smoke and pathological history. In conclusion, the use of public transport is associated with the presence of ILI in a group of university students from Lima.
POLíTICAS SOBRE EL SOFTWARE LIBRE EN EL CONTEXTO EDUCATIVO ESPA OL
ángel San Martín Alonso,Cristina Sales Arasa,José Peirats Chacón
Pixel-Bit , 2010,
Abstract: El artículo analiza las disfunciones que suscita en las prácticas escolares la aplicación del software libre. Hecho que se produce tanto por la peculiaridad de esta tecnología como por las políticas que promueven los proyectos institucionales de difusión del SL. Cómo tales políticas condicionan las prácticas de ense anza? Desde el enfoque de los estudios de Ciencia, Tecnología y Sociedad, tratamos de responder al interrogante estudiando varios centros de primaria con técnicas de corte cualitativo. Concluimos que las políticas enfatizan la difusión del SL, pero son remisas en estrategias de acompa amiento para asegurar el éxito de su aplicación.
Cómo atraer más y mejores trabajos a CIMEL?
Percy Manuel Mayta Tristán
CIMEL. Ciencia e Investigación Médica Estudiantil Latinoamericana , 2004,
Abstract:
The Promoter of the Cereal VERNALIZATION1 Gene Is Sufficient for Transcriptional Induction by Prolonged Cold
Maria M. Alonso-Peral, Sandra N. Oliver, M. Cristina Casao, Aaron A. Greenup, Ben Trevaskis
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0029456
Abstract: The VERNALIZATION1 (VRN1) gene of temperate cereals is transcriptionally activated by prolonged cold during winter (vernalization) to promote flowering. To investigate the mechanisms controlling induction of VRN1 by prolonged cold, different regions of the VRN1 gene were fused to the GREEN FLUORESCENT PROTEIN (GFP) reporter and expression of the resulting gene constructs was assayed in transgenic barley (Hordeum vulgare). A 2 kb segment of the promoter of VRN1 was sufficient for GFP expression in the leaves and shoot apex of transgenic barley plants. Fluorescence increased at the shoot apex prior to inflorescence initiation and was subsequently maintained in the developing inflorescence. The promoter was also sufficient for low-temperature induction of GFP expression. A naturally occurring insertion in the proximal promoter, which is associated with elevated VRN1 expression and early flowering in some spring wheats, did not abolish induction of VRN1 transcription by prolonged cold, however. A translational fusion of the promoter and transcribed regions of VRN1 to GFP, VRN1::GFP, was localised to nuclei of cells at the shoot apex of transgenic barley plants. The distribution of VRN1::GFP at the shoot apex was similar to the expression pattern of the VRN1 promoter-GFP reporter gene. Fluorescence from the VRN1::GFP fusion protein increased in the developing leaves after prolonged cold treatment. These observations suggest that the promoter of VRN1 is targeted by mechanisms that trigger vernalization-induced flowering in economically important temperate cereal crops.
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