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Search Results: 1 - 10 of 7256 matches for " Julio Armas "
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Hybrid Microoptical WDM Receiver for PON Communication
Vitezslav Jerabek,Julio Armas,Vaclav Prajzler
Advances in Electrical and Electronic Engineering , 2012,
Abstract: The paper presents the design, simulation and construction results of the wavelength division multiplex (WDM) optical hybrid receiver module for the passive optical network (PON). The optical WDM receiver was constructed using system of three micromodules in the new circle topology. The optical micromodule contains multimode fiber pigtail 50/125 μm, VHGT filter with collimation lens and two microwave optoelectronics receiver micromodules (OE receiver micromodules). OE receiver micromodules were designed by use small signal equivalent electrical circuit model and noise model, from which the mathematically solved the transmittance function, which was used for calculation and simulation of the optimal frequency characteristics and signal to noise ratio. For determine the limit frequency of OE receiver micromodule, the transcendent equation with transmittance function was numerically solved. OE receiver micromodule was composed of decollimation lenses and microwave optoelectronics receivers with bandwidth 2,5 GHz and alternatively in SMD technology with bandwidth 1,25 GHz, using the thin layer hybrid technology. WDM receiver use radiation 1490 nm for internet and 1550 nm for digital TV signals download information.
Mathematical Model of the Criterion of Optimization by Compensation for Designing Commercial Bottles with Lateral Surfaces of Revolution and a Straight Section along Its Silhouette  [PDF]
Lizandro B. R. Zegarra, Luis E. G. Armas, Aida D. Reyna, Julio A. L. Vergara, Fidel A. V. Obeso
Open Journal of Optimization (OJOp) , 2017, DOI: 10.4236/ojop.2017.63009
Abstract: In this article, the mathematical foundations of the so called Criterion of Optimization by Compensation for designing commercial bottles with a straight section along its silhouette and with lateral surfaces of revolution is presented. Such mathematical model uses as main tools, Lagrange polynomial interpolation and Newton’s Method for Nonlinear Systems being first necessary to formulate and demonstrate a theorem. It was redesigned and manufactured a bottle of a half-liter of Fanta soda of the well-known Coca Cola Company, which uses 18.86% more material that such criterion establishes. It was expected that the redesigned bottle use 4.91% more of material with respect to what is established by the Criterion of Optimization by Compensation. However, it was reported a 13% of mistake due to important limitations that must be overcome.
Evaluación termodinámica de sistemas de climatización centralizados por agua helada usando herramientas de inteligencia artificial
Armas,Juan Carlos; Lapido Rodríguez,Margarita; Gómez,Julio Rafael; Valdivia Nodal,Yarelis;
Ingeniería e Investigación , 2011,
Abstract: an analysis of a chilled water central air conditioning system is presented. the object was to calculate main cycle component irreversibility, as well as evaluating this indicator′s sensitivity to operational variations. artificial neural networks (ann), genetic algorithms (ga) and matlab tools were used to calculate refrigerant thermodynamic properties during each cycle stage. these tools interacted with equations describing the system′s thermodynamic behaviour. refrigerant temperature, when released from the compressor, was determined by a hybrid model combining the neural model with a simple genetic algorithm used as optimisation tool; the cycle′s components which were most sensitive to changes in working conditions were identified. it was concluded that the compressor, evaporator and expansion mechanism (in that order) represented significant exergy losses reaching 85.62% of total system irreversibility. a very useful tool was thus developed for evaluating these systems.
Aproximación a los criterios diagnósticos para la definición de deterioro cognitivo leve: modelos de diagnóstico y evaluación
Armas Castro,Julio; Carrasco García,Mayra; Angell Valdés,Sussette; López Mena,Yanet;
MediSur , 2009,
Abstract: for years the term slight cognitive impairment has been used in literature as a transitional stage between normal aging and a slight alzheimer?s disease and in conversion studies it has been associated to quantitative and qualitative alterations that support that support the hypothesis that slight cognitive impairment constitutes an early stage of dementia in most of the patients. in this search the most updated diagnostic criteria on the topic have been reviewed looking for both a diagnostic consensus among the multiple and heterogeneous symptoms of this disorder and a clear, concise and uniform criterion that allow to reach a right definition and diagnosis of patients with slight cognitive impairment.
Nuevo procedimiento para la evaluación de los motores monofásicos de inducción
de Armas Teyra,Marcos Alberto; Gómez Sarduy,Julio Rafael; Viego Felipe,Percy Rafael;
Ingenier?-a Energ??tica , 2013,
Abstract: in this paper was developed an algorithm based in air gap torque method to evaluate the performance of single phase induction motors. the developed shaft power, efficiency and other parameters are determined using a power analyzer installed in motor terminals in field conditions. results are adequate independently if there exist voltage or frequency deviation, voltage unbalance or different voltage phase between main and auxiliary winding and different spatial disposition of windings, wire size or winding distribution. the solution is obtained without knowledge of motor equivalent circuit's parameters. as cases its application to split phase, permanent capacitor and asymmetric motors are exposed comparing the results with the classic rotating field theory.
LOS FACTORES DE PROGRESION DEL DETERIORO COGNITIVO LEVE A LA ENFERMEDAD DE ALZHEIMER
Armas Castro,Julio; Carrasco García,Mayra Rosa; Angel Valdés,Sussette;
Revista Habanera de Ciencias M??dicas , 2008,
Abstract: mild cognitive decline and dementia are both important health problems in the 21ist century . given it’s connection with age, we have stated how, in the last decade a continuum increase in it’s incidence and prevalence is related with the progressive increase time of life. having in consideration the studies of progression made up to date and the cohorts of following of mild cognitive decline, we can point out some markers of evolution, given: advanced age, the presence of at least one apoe 4 allele in genetic screening, diminished hippocampus area, low punctuations in psychometric tests, a major cardiovascular compromise and family background of first blood line relatives with dementia, among others. we had the purpose to approach the subject of the predictor factors with the main objective to offer updated information about the performed studies in connection with the topic.
Metástasis ganglionar cervical de melanoma de extensión superficial: A la vista, pero ignorado Cervical ganglionary metastasis of superficially-extended melanoma: Observed, but ignored
Raúl Calderín Bousa,Luis A. Senra Armas,Julio C. Pérez Suárez
Revista Cubana de Medicina , 2007,
Abstract:
An Approach to Diagnostic Criteria for the Definition of Slight Cognitive Impairment Aproximación a los criterios diagnósticos para la definición de deterioro cognitivo leve
Julio Armas Castro,Mayra Rosa Carrasco García,Sussette Angell Valdés,Yanet López Mena
MediSur , 2009,
Abstract: For years the term slight cognitive impairment has been used in literature as a transitional stage between normal aging and a slight Alzheimer’s disease and in conversion studies it has been associated to quantitative and qualitative alterations that support that support the hypothesis that slight cognitive impairment constitutes an early stage of dementia in most of the patients. In this search the most updated diagnostic criteria on the topic have been reviewed looking for both a diagnostic consensus among the multiple and heterogeneous symptoms of this disorder and a clear, concise and uniform criterion that allow to reach a right definition and diagnosis of patients with slight cognitive impairment. El término deterioro cognitivo leve se ha usado en la literatura durante varios a os como un estado de transición entre el envejecimiento normal y una enfermedad de Alzheimer muy leve, se asocia además a alteraciones cuantitativas y cualitativas, en estudios de conversión, que apoyan la hipótesis de que se trata de estadios iniciales de demencia en una gran proporción de casos. En este trabajo se realiza una revisión de los principales criterios diagnósticos que se emplean en la actualidad para llegar a un consenso diagnóstico dentro de la heterogeneidad de síntomas y definir con criterios claros, concretos y uniformes a los pacientes con deterioro cognitivo leve.
Evaluación de la efectividad de la desinfección con formaldehidomediante tres métodos de control bacteriologicos (Evaluation of theeffectiveness of formaldehyde disinfection by means of three methods ofbacteriological control)
Omelio Cepero Rodríguez,Enrique A. Silveira Prado,Victoria Fernández Armas,Julio C. Castillo Cuenca
REDVET , 2007,
Abstract: Se evaluó la calidad de la desinfección profiláctica con formaldehído al 2% y a temperatura de 70°C en una instalación pecuaria no suficiente. Previa limpieza mecánica se aplicó la solución desinfectante mediante una unidad móvil y después de transcurridas tres horas de exposición se realizó el muestreo mediante hisopaje de pisos, paredes, comederos y bebederos, procediéndose posteriormentea la inoculación en paralelo de tres medios de cultivos: Heifetz modificado (HM), Heifetz modificado con histidina al 0,1% (HMH) y Caldo Lactosado con Azul de Bromotimol (CLAB) para coliformes.Transcurrido el periódo de incubación, los resultados se evaluaron estadísticamente mediante la prueba de comparación de proporciones. En las condiciones del experimento se constató mayor efectividaden términos de detectabilidad del CLAB, con diferencias estadísticamente significativas (p < 0,05) respecto al HM(41,0 vs. 17,9%). La diferencias entre las comparaciones CLAB vs. HMH (41,0 vs.30,8%) y HM vs HMH (17,9 vs. 30,8%) no fueron significativas.
LOS FACTORES DE PROGRESION DEL DETERIORO COGNITIVO LEVE A LA ENFERMEDAD DE ALZHEIMER Roles in the progression from mild cognitive decline, to Alzheimer’s disease
Julio Armas Castro,Mayra Rosa Carrasco García,Sussette Angel Valdés
Revista Habanera de Ciencias M??dicas , 2008,
Abstract: El deterioro cognitivo y la demencia constituyen uno de los problemas de salud pública más importantes del siglo XXI. Dada su relación con la edad, constatamos en la última década un continuo incremento tanto en su incidencia como en su prevalencia, secundariamente al aumento progresivo de la longevidad en la población. Teniendo en cuenta los estudios de progresión realizados hasta la fecha y las cohortes de seguimiento del deterioro cognitivo podemos se alar algunos marcadores de evolución: edad avanzada, presencia de al menos un alelo de APOE 4 en el screenning genético, disminución del área hipocampal, puntuaciones bajas en test psicométricos, mayor compromiso o asociación a factores de riesgo vascular y antecedentes de familiares de primera línea con demencia, entre otros. Nos propusimos abordar el tema de los factores predictores con el objetivo principal de brindar información actualizada sobre los estudios realizados en relación con este tema. Mild cognitive decline and dementia are both important health problems in the 21ist century . Given it’s connection with age, we have stated how, in the last decade a continuum increase in it’s incidence and prevalence is related with the progressive increase time of life. Having in consideration the studies of progression made up to date and the cohorts of following of mild cognitive decline, we can point out some markers of evolution, given: advanced age, the presence of at least one APOE 4 allele in genetic screening, diminished hippocampus area, low punctuations in psychometric tests, a major cardiovascular compromise and family background of first blood line relatives with dementia, among others. We had the purpose to approach the subject of the predictor factors with the main objective to offer updated information about the performed studies in connection with the topic.
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