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Search Results: 1 - 10 of 156691 matches for " H. Prieto-Alfonso "
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Multi Anode Photomultiplier Tube Reliability Assessment for the JEM-EUSO Space Mission
H. Prieto-Alfonso,L. del Peral,M. Casolino,K. Tsuno,T. Ebisuzaki,M. D. Rodríguez Frías,JEM-EUSO Collaboration
Physics , 2015, DOI: 10.1016/j.ress.2014.08.014
Abstract: Reliability assessment in concerned with the analysis of devices and systems whose individual components are prone to fail. This reliability analysis documents the process and results of reliability determination of the JEM-EUSO photomultiplier tube component using the methods 217 Plus. Quantum efficiency degradation and radiation hardness assurance. In conclussion, the levels of damage suffered by the PMTs which comprise the focal surface of JEM-EUSO Space Telescope, are acceptable. The results show as well the greatest contribution to the failure is due to radiation SET. The guaranteed performance of this equipment is a 99.45 per cent, an accepted value of reliability thus fulfilling the objectives and technological challenges of JEM-EUSO.
Tannic Acid-Dependent Modulation of Selected Lactobacillus plantarum Traits Linked to Gastrointestinal Survival
Inés Reverón, Héctor Rodríguez, Gema Campos, José Antonio Curiel, Carmen Ascaso, Alfonso V. Carrascosa, Alicia Prieto, Blanca de las Rivas, Rosario Mu?oz, Félix López de Felipe
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0066473
Abstract: Background Owing to its antimicrobial properties dietary tannins may alter the functional efficacy of probiotic lactobacilli in the gastrointestinal (GI)-tract influencing their growth, viability and molecular adaptation to the intestinal environment. Methods and Findings The effects of tannic acid on Lactobacillus plantarum WCFS1 were studied by in vitro growth monitoring and visualizing the morphological alteration on the cell wall using transmission electron microscopy. Growth upon tannic acid was characterized by dose-dependent reductions of initial viable counts and extended lag phases. Lag phase-cells growing upon 0.5 mM tannic acid were abnormally shaped and experienced disturbance on the cell wall such as roughness, occasional leakage and release of cell debris, but resumed growth later at tannic acid concentrations high as 2.5 mM. To gain insight on how the response to tannic acid influenced the molecular adaptation of L. plantarum to the GI-tract conditions, gene expression of selected biomarkers for GI-survival was assessed by RT-qPCR on cDNA templates synthetized from mRNA samples obtained from cells treated with 0.5 or 2 mM tannic acid. Tannic acid-dependent gene induction was confirmed for selected genes highly expressed in the gut or with confirmed roles in GI-survival. No differential expression was observed for the pbp2A gene, a biomarker negatively related with GI-survival. However PBP2A was not labeled by Bocillin FL, a fluorescent dye-labeled penicillin V derivative, in the presence of tannic acid which suggests for enhanced GI-survival reportedly associated with the inactivation of this function. Conclusions Probiotic L. plantarum WCFS1 is able to overcome the toxic effects of tannic acid. This dietary constituent modulates molecular traits linked to the adaptation to intestinal environment in ways previously shown to enhance GI-survival.
Numerical Approximation of Fractal Dimension of Gaussian Stochastic Processes  [PDF]
Freddy H. Marin Sanchez, William Eduardo Alfonso
Applied Mathematics (AM) , 2014, DOI: 10.4236/am.2014.512169
Abstract:

In this paper we propose a numerical method to estimate the fractal dimension of stationary Gaussian stochastic processes using the random Euler numerical scheme and based on an analytical formulation of the fractal dimension for filtered stochastic signals. The discretization of continuous time processes through this random scheme allows us to find, numerically, the expected value, variance and correlation functions at any point of time. This alternative method for estimating the fractal dimension is easy to implement and requires no sophisticated routines. We use simulated data sets for stationary processes of the type Random Ornstein Uhlenbeck to graphically illustrate the results and compare them with those obtained whit the box counting theorem.

Propiedades Psicométricas del Cuestionario de Auto Reporte de la Calidad de Vida KIDSCREEN-27 en Adolescentes Chilenos
Alfonso Urzúa,Edith Cortés,Susana Vega,Lesley Prieto
Terapia Psicológica , 2009,
Abstract: Se evalúa, las propiedades psicométricas del cuestionario de Calidad de Vida KIDSCREEN-27 adaptado a ni os/as y adolescentes chilenos. Participaron 1678 sujetos escolarizados de entre 8 y 18 a os. Se evaluó tanto la consistencia interna como indicadores de validez de constructo, discriminante y convergente. El alfa de Cronbach de la escala total como de las distintas dimensiones es superior a 0.70. Los análisis factoriales exploratorio y confirmatorio arrojan evidencia de una estructura similar a la teórica de cinco dimensiones. El instrumento es capaz de discriminar entre hombres y mujeres, así como entre rangos de edad, en diferentes dimensiones. Los resultados permiten decir que el KIDSCREEN-27 presentó coeficientes de fiabilidad y validez aceptables, similares a los de la versión original, permitiendo disponer de un nuevo instrumento que evalúe calidad de vida en Chile y a la vez comparar los resultados obtenidos con otros países que utilicen este instrumento.
MOST FREQUENT ERRORS IN JUDO UKI GOSHI TECHNIQUE AND THE EXISTING RELATIONS AMONG THEM ANALYSED THROUGH T-PATTERNS
Alfonso Gutiérrez,Iván Prieto,José M. Cancela
Journal of Sports Science and Medicine , 2009,
Abstract: The purpose of this study is to provide a tool, based on the knowledge of technical errors, which helps to improve the teaching and learning process of the Uki Goshi technique. With this aim, we set out to determine the most frequent errors made by 44 students when performing this technique and how these mistakes relate. In order to do so, an observational analysis was carried out using the OSJUDO-UKG instrument and the data were registered using Match Vision Studio (Castellano, Perea, Alday and Hernández, 2008). The results, analyzed through descriptive statistics, show that the absence of a correct initial unbalancing movement (45,5%), the lack of proper right-arm pull (56,8%), not blocking the faller's body (Uke) against the thrower's hip -Tori- (54,5%) and throwing the Uke through the Tori's side are the most usual mistakes (72,7%). Through the sequencial analysis of T-Patterns obtained with the THèME program (Magnusson, 1996, 2000) we have concluded that not blocking the body with the Tori's hip provokes the Uke's throw through the Tori's side during the final phase of the technique (95,8%), and positioning the right arm on the dorsal region of the Uke's back during the Tsukuri entails the absence of a subsequent pull of the Uke's body (73,3%).
Plasma characterization of pulsed-laser ablation process used for fullerene-like CNx thin film deposition
Riascos, H.;Zambrano, G.;Prieto, P.;
Brazilian Journal of Physics , 2004, DOI: 10.1590/S0103-97332004000800014
Abstract: an in situ optical emission spectroscopy (oes) characterization was performed on pulsed-laser ablation (pla) process used for fullerene-like cnx thin film deposition at nitrogen pressures within the 5 - 100 mtorr range. plumes were generated by ablation of pyrolytic graphite (99.99%) target using a (500 mj, 7 ns, 1064 nm) nd: yag-pulsed laser. the spectra from the plume show, essentially, the presence of the band heads of cn violet vibrational/rotational b2s+ - x2s+ system and the characteristic c2 emission lines, belonging to the swan a3pg - x'3pu system. these excited cn and c2 molecules were generated by laser ablation and by collisions of the plume with the substrate surface. their vibrational temperatures were strongly dependent on nitrogen pressure during the deposition process and presented a decrease between 2.64 and 1.23 ev, as pressure increased from 5 to 100 mtorr. synthesis of fullerene-like structures required high molecular temperatures at the condensation surface. high concentrations of cn radicals in the plasma promoted nitrogen incorporation into the films. the oes plasma characterization allowed for a correlation of the concentration and vibrational temperatures of cn and c2 species present in the plasma with the fullerene-like cnx film composition and bonding, determined by xps, ir, and raman spectroscopy.
La formación investigativa en la carrera de Estomatología desde la perspectiva de los estudiantes
Rosales Reyes,Sol ángel; Alfonso Betancourt,Natividad; Prieto Capote,Víctor Manuel; Lorenzo Gácita,Yadira;
Revista Cubana de Estomatolog?-a , 2009,
Abstract: introduction: research training to be conductive to the career is a essential feature for the future work of odontology professional. satisfaction of those receiving this training is one of the features to be into account in curriculum evaluation. objectives: to identify how the student consider its training to face the research tasks and of the tutor contribution to it and to also to identify which are the main activities influenced in student research training throughout the career. methods: a cross-sectional and descriptive study was conducted using the theoretical methods approaching the subject during the past 5 years and the survey empirical method applied to fourth and fifth years of the career studying in "raúl gonzález sánchez" odontology faculty for information collection. results: the 100 % of person polled considered as important the scientific research for the profession development, but only the 58.1 % of students refered to be trained to confront the research tasks. the features that more influenced in its research training are: student scientific meeting, scientific information search, the final works carrying out on subjects, the preparation for seminars and the work as assistant student. conclusion: the research training is still insufficient from the student perspectives.
Autoreporte de la Calidad de Vida en Ni os y Adolescentes Escolarizados Self-report of Quality of Life in School Age Children and Adolescents
ALFONSO URZúA M,EDITH CORTéS R,LESLEY PRIETO C,SUSANA VEGA B
Revista chilena de pediatría , 2009,
Abstract: Introducción: Aun cuando se ha ido incorporando la calidad de vida como un indicador comprensivo del estado de salud, no se tienen valores de referencia. Objetivo: Reportar valores que puedan ser utilizados como referencia en el campo clínico y de la salud pública. Método: Se evalúa a 1 678 ni os y adolescentes de entre 8 y 18 a os de establecimientos públicos, subvencionados y particulares de la ciudad de Antofagasta a través del cuestionario KIDSCREEN-27. Resultados: Se reportan las medias y deciles de cada una de las cinco dimensiones evaluadas (bienestar físico, bienestar psicológico, relación con los padres y autonomía, apoyo social y pares, ambiente escolar) para hombres y mujeres, rangos de edad y tipos de establecimiento educacional. Conclusión: Los valores presentados en las diferentes dimensiones evaluadas pueden ser utilizados como valores de referencia en población infanta juvenil chilena. En general, los hombres reportan una mejor calidad de vida que las mujeres, al igual que los rangos de menor edad y los establecimientos privados. Estos hallazgos son similares a los reportados en la población espa ola utilizando similar instrumento. Background: Although quality of life has been incorporated as a comprehensive indicator of health status, there are no standards available. Objective: To report values that can be used as standards in clinical and public health areas. Methods: 1 678 children and adolescents (8 to 18 years old) were evaluated. They came from public, semiprivate and private schools in the city of Antofagasta (North of Chile) utilizing KIDSCREEN-27 questionnaire. Results: The study shows mean and decile values for each of the five domains assessed (physical wellbeing, psychological wellbeing, relationship with parents and autonomy, social support and peers, school environment) for gender, age range and type of school. Conclusion: Values were presented which can be used as standards for Chilean children and adolescents in the specified domains. In general, best quality of life was found among boys, younger age children, and those from private schools. These findings are similar to those reported in studies in Spain, utilizing the same instrument.
Analgesia electroacupuntural en la toma de muestra para biopsia de médula ósea Electro-acupunctural analgesia applied to sample-taking for bone marrow biopsy
Julio D Fernández águila,Reynaldo Quintana Ponce,Tamara Guerra Alfonso,Leobaldo Prieto Jiménez
Revista Cubana de Hematolog?-a, Inmunolog?-a y Hemoterapia , 2001,
Abstract:
La formación investigativa en la carrera de Estomatología desde la perspectiva de los estudiantes The research training in career of Odontology from the student perspective
Sol ángel Rosales Reyes,Natividad Alfonso Betancourt,Víctor Manuel Prieto Capote,Yadira Lorenzo Gácita
Revista Cubana de Estomatolog?-a , 2009,
Abstract: Introducción: La formación investigativa que propicia la carrera es un aspecto vital para el trabajo futuro del profesional de la Estomatología. La satisfacción de quienes reciben esta preparación es uno de los aspectos a tener en cuenta en la evaluación de un currículo. Objetivos: Identificar cómo valoran los estudiantes su formación para enfrentar las tareas de investigación y la contribución del tutor a la misma e identificar cuáles son las principales actividades que influyeron en la formación investigativa de los estudiantes a lo largo de la carrera. Métodos: Se realizó un estudio descriptivo transversal, con la utilización de métodos teóricos como fueron el análisis y síntesis de la información, con una revisión de las principales bibliografías que abordan el tema en los últimos cinco a os y el método empírico de la encuesta, aplicada a estudiantes de cuarto y quinto a os de la carrera que estudian en la Facultad de Estomatología "Raúl González Sánchez", para la recogida de la información. Resultados: El 100 % de los encuestados consideró importante la investigación científica para el desarrollo de la profesión; el 58,1 % de los estudiantes refirió estar preparado para enfrentar las tareas investigativas. Los aspectos que a su criterio más han contribuido a su formación investigativa son: la jornada científica estudiantil, la búsqueda de información científica, la realización de trabajos finales en asignaturas, preparación para los seminarios y el trabajo como alumno ayudante. Conclusión: La formación investigativa es aún insuficiente desde la perspectiva de los estudiantes. Introduction: Research training to be conductive to the career is a essential feature for the future work of Odontology professional. Satisfaction of those receiving this training is one of the features to be into account in curriculum evaluation. Objectives: To identify how the student consider its training to face the research tasks and of the tutor contribution to it and to also to identify which are the main activities influenced in student research training throughout the career. Methods: A cross-sectional and descriptive study was conducted using the theoretical methods approaching the subject during the past 5 years and the survey empirical method applied to fourth and fifth years of the career studying in "Raúl González Sánchez" Odontology Faculty for information collection. Results: The 100 % of person polled considered as important the scientific research for the profession development, but only the 58.1 % of students refered to be trained to confront the research ta
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