Sample records for MODULACION DE FRECUENCIA (frequency modulation)
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1

Implicaciones clínicas y pronósticas del estudio circadiano de la modulación simpático-vagal de la variabilidad de la frecuencia cardiaca en pacientes con hipertensión arterial pulmonar grave/ Clinical implications and prognostic significance of the study on the circadian variation of heart rate variability in patients with severe pulmonary hypertension

Rosas-Peralta, Martín; Sandoval-Zárate, Julio; Attie, Fause; Pulido, Tomás; Santos, Efrén; Granados, Nuria Z.; Miranda, Teresa; Escobar, Verónica
2006-02-01

Resumen en español Introducción: La reducción en la variabilidad de la frecuencia cardiaca ha sido identificada como factor de riesgo en enfermedad cardiovascular, pero su descripción en hipertensión arterial pulmonar severa se desconoce. Material y métodos: Se estudiaron pacientes con hipertensión arterial pulmonar grave, 32 con hipertensión pulmonar primaria, 34 con hipertensión pulmonar secundaria a cardiopatía congénita (Eisenmenger) y 44 sujetos control sin evidencia de enfer (mas) medad. La evaluación del registro ambulatorio de la frecuencia cardiaca se realizó por métodos convencionales. El análisis espectral y la relación a baja y alta frecuencia se realizó utilizando el método de Fourier. Comparaciones entre día y noche se realizó entre los grupos. Después de conocer el perfil circadiano, 15 pacientes con hipertensión pulmonar fueron seleccionados para recibir tratamiento al azar con Treprostinil (Prostaglandina) o placebo por vía subcutánea. Posteriormente (3 meses) se analizaron nuevamente los parámetros de variabilidad de frecuencia cardiaca y de hemodinámica para conocer el impacto de dicha terapéutica. Resultados: Se detectó un estado franco de hipertonía simpática en el grupo de hipertensión pulmonar, sobre todo en los pacientes con hipertensión pulmonar primaria. El efecto de Treprostinil fue claramente asociado con disminución del tono simpático y un aumento de la capacidad física. Conclusiones: Los pacientes con hipertensión arterial pulmonar, cursan con equilibrio simpático-vagal alterado sobre todo durante el día. Hay pérdida del ritmo circadiano. Dichos trastornos pueden ser reversibles con la aplicación de treprostinil. El equilibrio simpático-vagal de la frecuencia cardiaca es un instrumento no invasivo que permite estratificar mejor al paciente con hipertensión arterial pulmonar grave. Resumen en inglés Background: A reduction of heart rate variability (HRV) is currently considered an independent risk factor for morbidity, mortality and severity of several cardiac disease, however, the dynamic sympathovagal modulation on HR V during 24 hr in primary pulmonary hypertension (PPH) had not been described. Methods: 24 hr Holter monitoring (HM) were recorded in 32 patients (mean age 34, +/-12, 90% female) with severe primary pulmonary hypertension (mean pulmonary pressure, 9O (mas) :t: 12mm Hg), and in 34 patients (mean age 36 +/-14, 60% female) with Eisenmenger syndrome (ES) secondary to septal ventricular defect or atent duc tus arteriosus. A control group (n=44) paired for age, gender and arterial pulmonary pressure was included. HR V time and spectral parameters (mean, SDNN, SDANN, rMSSD, PNN50, LF, HF and LF/HF ratio) were analyzed during three periods: 24 hr; day (8-22:00), night (23-07:00) and also every hour of recording at 5 min-intervals). After detection of sympatho-vagal balance 15 patients were randomized, Treprostinil (prostaglandin) was administered to 6 patients and subcutaneous placebo to 9. Results: HRV frequency parameters during 24 hr HM were significantly different among groups. LF/HF (day) 5.9:1:12.5:1:1P.001 and LF/ HF night)2.8:t1vs.1.5:1:.8.034. Sympathovagal modulation on 24hr HRV showed that heart rate circadian rhythm is clearly altered in both PPH and ES, but the sympathetic tone in PPH is higher at l 24hr. (p

Scientific Electronic Library Online (Spanish)

2

EFECTOS DE LA MODULACIÓN DE FASE CRUZADA SOBRE LA PROPAGACIÓN DE ONDAS EN FIBRA ÓPTICA

Saavedra G, Fideromo; Lamas N, Álvaro; Fernández B, Marco; Cepeda P, Yonatan
2005-12-01

Resumen en español La modulación de fase cruzada (XPM) es un importante fenómeno que limita el desempeño de los sistemas ópticos de alta velocidad. En este trabajo se analizan y realizan tres modelos matemáticos diferentes que nos permiten comprobar y determinar las dependencias de XPM con respecto a la dispersión cromática de la fibra, la separación entre las longitudes de ondas, la potencia y la frecuencia de modulación Resumen en inglés The cross-phase modulation (XPM) is an important phenomenon that limits the performance of the high speed optical systems. In this work three different mathematical models are analyzed and realiced, that they allow to verify and to determine the dependencies of XPM with respect to the chromatic dispersion of the fiber, the separation between the wavelengths, the power and the modulating frequency

Scientific Electronic Library Online (Spanish)

3

DETECCIÓN DE NUDOS EN MADERA CON TÉCNICAS DE MICROONDAS

BARADIT, E; AEDO, R; CORREA, J
2003-01-01

Resumen en español En este trabajo se lleva a cabo un estudio preliminar de detección de nudos en madera sólida creciente en Chile, por medio de la utilización de radiación de microondas. Se conformo un sistema de prueba constituido por un arreglo de diodos detectores de microondas. Se utilizaron muestras de madera limpia de nudos y con nudos a la vista con diferente contenido de humedad. Se observo que la atenuación de la señal al atravesar los nudos se debía principalmente al cambi (mas) o de la orientación de las fibras en el nudo y no significativamente al cambio de densidad. Esto significa que para la detección de la presencia de nudos y defectos en la madera es conveniente hacer un análisis de amplitud y de fase de la señal en cada diodo, lo que implica un proceso de modulación con el objetivo de bajar la frecuencia de trabajo. En este trabajo sólo se estudiaron las variaciones en los niveles de amplitud de voltaje Resumen en inglés In this preliminary work a study of knots detection in Chilean wood using microwave radiation is realized. A probe system of microwave diode detector array was designed and built. Some specimens of wood with and without knots and different moisture content are used. It was observed that the attenuation of microwave signal mainly is due to fiber orientation changes and not to density changes. This means that for knots and irregularities detection in wood an amplitude and p (mas) hase analisis is required which implies a modulation process for lowering the operation frequency. In this work only the voltage level distribution is studied

Scientific Electronic Library Online (Spanish)

4

Diseño de moduladores digitales empleando FPGA para escáneres de resonancia magnética/ Design of digital modulators using FPGA for magnetic resonance scanners

Sóñora Mengana, Alexander
2005-09-01

Resumen en español En este trabajo se presenta la metodología para diseñar moduladores digitales para equipos de resonancia magnética empleando dispositivos FPGA. Luego de seleccionar la frecuencia de muestreo del sistema, se pasa al diseño del sintetizador y del mezclador, se escoge la familia de los FPGA a emplear y finalmente el conversor digital analógico. El método se aplica al diseño de un modulador para tomógrafos Giroimag empleando dos FPGA XC4003e-pc84 de Xilinx. El sinteti (mas) zador tiene una precisión superior a 0.1Hz, frecuencia máxima de trabajo de 4MHz y un nivel de espurios máximo de 60dB por debajo de la componente fundamental, el mezclador realiza la modulación de esta señal con un pulso gaussiano de 8 bits con frecuencia de muestreo máxima de 5.12MHz. El modulador obtenido por este método es más sencillo eléctricamente que uno analógico de iguales características. El método propuesto permite realizar de forma sencilla diseños de moduladores digitales para equipos de resonancia magnética. Resumen en inglés This paper presents the methodology for the design of digital modulators for magnetic resonance equipment using Field Programmable Gate Arrays (FPGA). After selecting the system sampling frequency, synthesizer and mixer are designed, the family of FPGA to be used and finally the digital-analog converter are chosen. The method is applied to the design of a modulator for Giroimag scanners using two XC4003e-pc84 FPGA of Xilinx. The synthesizer has a precision over 0.1 Hz, a (mas) maximum output frequency of 4MHz and a maximum level of spur of 60dB below the fundamental component, the mixer carries out the modulation of the carrier with a gaussian pulse of 8 bits with a maximum sampling frequency of 5.12MHz. The modulator obtained by this method is electrically simpler than an analogical one of same characteristics. The proposed method allows to carry out in a simple way designs of digital modulators for magnetic resonance equipment.

Scientific Electronic Library Online (Spanish)

5

Modulación por multiportadoras tipo OFDM, las bases de la nueva generación de transmisión de información

Ramírez Behaine, Carlos Alberto
2006-07-01

Resumen en español Las proyecciones de demanda del servicio de banda ancha muestran un crecimiento vertiginoso en las próximas décadas. El esquema de modulación que soporta el nivel físico de tales servicios es el de multiplexión por división de frecuencias ortogonales (OFDM) que, gracias a sus características ortogonales, logran sobrepasar las barreras de transmisión impuestas por los canales de comunicaciones. Después de ilustrar los fundamentos del porqué OFDM logra su cometido (mas) , detallando el mapeamiento y modelo de comunicaciones en banda base, las aplicaciones potenciales actuales y futuras de OFDM son indicadas. Se prevé que surja un modelo para las nuevas generaciones, propuestas en espacios concurrentes en tiempo, frecuencia y código. Resumen en inglés The projections of the demand of broadband services show a vertiginous growth in the next decades. The modulation scheme that supports the physical level of such services is the Orthogonal Frequency-Division Multiplexing (OFDM) that thanks to their orthogonal characteristics, overcome the transmission barriers imposed by the communication channels. After illustrating the fundamentals of why OFDM achieves its objective and detailing the mapping and model of communications (mas) in base band, the present and future of potential applications of OFDM are indicated. It is likely that a model for the new generations, in which time, frequency and code concur in space, will arise

Scientific Electronic Library Online (Spanish)

6

TRASTORNO DE ATENCIÓN EN LAS ESCUELAS PÚBLICAS DE UNA LOCALIDAD DE BOGOTÁ: PERCEPCIÓN DE LOS MAESTROS/ Teachers perception of attention deficit disorder in some public schools from Bogota

Talero Gutiérrez, Claudia; Espinosa Bode, Andrés; Vélez Van Meerbeke, Alberto
2005-10-01

Resumen en español Antecedentes: el trastorno por déficit de atención se diagnostica cada vez con mayor frecuencia en nuestro medio. Los únicos datos de prevalencia que se tienen en el país proceden de Antioquia pero se desconoce la frecuencia en otras regiones del país. Objetivo: evaluar la percepción de los maestros de escuelas de una localidad de Bogotá sobre la presencia del trastorno de atención en sus alumnos. Material y métodos: se realizaron conferencias magistrales sobre l (mas) a evolución de la atención durante el desarrollo, las alteraciones que se presentan y se engloban en el término trastorno por déficit de atención y discusiones de grupo. Al finalizar se aplicó una encuesta de seis puntos desarrollados en formato de preguntas abiertas que estaban relacionadas con el número total de niños, la distribución por género y las características de la atención de aquellos que tenían a cargo. Resultados. 58 maestros de 10 escuelas percibieron que 612 (31%) alumnos de preescolar y primaria tenían problemas de atención. La distribución por grados mostró un pico importante en el tercer grado. No hubo diferencias significativa en cuanto al género pero si respecto a la preferencia manual. Conclusión. Los datos recogidos demuestran una importante percepción de dificultades de atención en los niños que invita a una reflexión en relación a medidas de tipo pedagógico y de modulación de la conducta, así como a una búsqueda de tipo estadístico y etiológico formal. Resumen en inglés Background: the frequency of diagnosis of attention deficit disorder is increasing in our environment. The only available prevalence data in Colombia is from Antioquia and, the prevalence of the disorder is unknown in the rest of the country. Objective: to evaluate the perception of teachers of some schools from Bogota. The teachers reported the number of children considered with attention disorders after attending a workshop on this issue. Materials and methods: a confer (mas) ence of attention development, alterations and issues about attention deficit disorder was given. In the end of this conference, a survey of six topics was applied to the teachers. This survey asks about number of children, sex and other considerations. Results. 58 teachers from 10 schools perceived that 612 (31%) primary school students of a total of 1980 had attention problems. Distribution by grades showed an important increase in third grade.There were no gender significant differences but being left handed had a significant relation with Attention deficit disorder. Conclusion. The data collected show an important perception of attention problems in children underlining the need for pedagogical and modulation of conduct measures, as that of performing a formal statistical and etiological search.

Scientific Electronic Library Online (Spanish)

7

Diferencias en la modulación autónoma del corazón entre mujeres y hombres/ Differences in cardiac autonomic modulation between women and men

Lerma, Claudia; Vallejo, Maite; Urias, Karla; Hermosillo, Antonio G; Cárdenas, Manuel
2006-09-01

Resumen en español La diferencia en la modulación autónoma de la función cardiovascular entre los sexos es un tema controvertido, motivo de numerosos estudios. En este trabajo, se describe y compara el comportamiento de la variabilidad de la frecuencia cardíaca en 30 mujeres y 20 hombres mexicanos de 21 a 36 años de edad a quienes se realizó monitoreo Holter de 20 a 24 horas. Se estimaron los índices en el análisis a través del tiempo (SDNNN y rMSSD) y el espectral (FA, FB y FB/FA (mas) en valores absolutos y unidades normalizadas). El SDNN fue significativamente más elevado en los hombres. Al ajustar por la edad, hubo una correlación negativa con índices de actividad parasimpática (rMSSD y FA) en las mujeres. El acondicionamiento físico aumenta el SDNN en los hombres y las FA en las mujeres. En las mujeres el acondicionamiento físico aumenta la actividad parasimpática. La función autónoma cardiovascular sufre un deterioro paulatino asociado a la edad, sobre todo en los índices relacionados con la actividad parasimpática en las mujeres. Estos resultados muestran diferencias asociadas al sexo. Resumen en inglés Gender differences in cardiac autonomic modulation are a controversial topic in several studies. The aim of this study, was to describe and compare the heart rate variability in 30 women and 20 men, Mexicans, between 21 to 36 years of age. A 20 to 24 hours Holter monitoring was performed in all of them. Analysis of time (SDNNN and rMSSD), and frequency domains (HF, LF and LF/HF in absolute values and normalized units) were used. SDNN[IBM1] was significantly higher in men. (mas) When adjusted for age, there was a negative correlation in parasympathetic activity indexes (rMSSD and HF) in women. Physical training increased SDNN in men and HF in women. The increased parasympathetic activity found in women with physical training diminishes with age. These results demonstrate differences in cardiovascular autonomic modulation between women and men.

Scientific Electronic Library Online (Spanish)

8

Estimulación magnética transcraneal para síntomas negativos en la esquizofrenia: una revisión/ The transcraneal magnetic stimulation for the negative symptoms in schizofrenia: a review

Zelaya Vásquez, Rina María; Saracco-Álvarez, Ricardo A.; González Olvera, Jorge
2010-04-01

Resumen en español La estimulación magnética transcraneal (EMT) es un método no invasivo que utiliza campos magnéticos alternantes para inducir corrientes eléctricas en el tejido cortical en diferentes áreas cerebrales. Se considera una forma de tratamiento para diferentes trastornos psiquiátricos, especialmente en la depresión, adicciones y esquizofrenia. Está técnica terapéutica ofrece una vía innovadora para estudiar la excitabilidad de la corteza, la conectividad regional co (mas) rtical, la plasticidad de las respuestas cerebrales y las funciones cognitivas en el estado del enfermo. Aunque se han documentado resultados positivos en la estimulación de la CPF izquierda y en la CPF derecha, se sugiere que puede ejercer su acción beneficiosa a través de diversos mecanismos de acción aún no comprendidos en su totalidad. La corteza prefrontal humana es esencial en el control e integración de las emociones, la cognición y la regulación del Sistema Nervioso Autónomo. Numerosas conexiones neuronales bidireccionales se originan en la CPF y se extienden al resto de las áreas de asociación cortical, región insular, sistema límbico y los ganglios basales. La CPF modula la actividad dopaminérgica mesencefálica mediante una vía activadora y otra inhibidora, lo que permite una regulación sumamente fina de la actividad dopaminérgica. La vía activadora funciona por medio de proyecciones glutamatérgicas directas e indirectas a las células dopaminérgicas. La vía inhibitoria hace lo propio mediante eferencias glutamatérgicas prefrontales a las interneuronas GABAérgicas mesencefálicas y a las neuronas GABAérgicas estriatomesencefálicas. El modelo de la doble modulación del sistema dopaminérgico mesolímbico demuestra que la concentración dopaminérgica extracelular en el núcleo accumbens disminuye o aumenta después de la estimulación de la corteza prefrontal a baja o alta frecuencia, respectivamente. Dentro de los estudios que utilizan la EMT en la esquizofrenia, se ha encontrado que, tras una EMT de alta frecuencia (>1Hz) o repetititiva (EMTr), hay un aumento de la excitabilidad en varias áreas cerebrales, mientras que la excitabilidad cortical disminuye tras una EMT de baja frecuencia ( Resumen en inglés Schizophrenia is one of the most studied diseases in psychiatry and different dysfunctions of thinking, emotions, perception, movement, and behavior converge in it. These dysfunctions affect the quality of life of the patients in different ways. It is a disease that has been observed in the whole world, with a 0.5 to 1.5% prevalence among adults. Although the biological basis of schizophrenia is not clear enough, the dopaminergic hypothesis is preponderant in our understa (mas) nding of the symptoms of the disease. A mesolimbic pathway hyperactivity is related to a positive symptomathology, while a prefrontal dopaminergic hypofunction relates to negative symptoms. It has been observed that using serotoninergic antagonists, which promote dopaminergic activity in the prefrontal cortex, translates in to a reduction of the intensity of negative symptoms. This negative syndrome includes a difficulty to initiate new activities (apathy), speech and creativity impoverishment (alogia), alterations in emotional expression, and a lack of capacity to experiment joy. Patients with negative symptoms present gray and white matter loss in left-sided cerebral structures, including temporal lobe, anterior cingulated, and medial frontal cortex. Such a loss seems to be more evident in prefrontal regions, such as the dorsolateral prefrontal region, which connects with anterior temporal structures. Persistent negative symptomathology is a concept proposed by Buchanan, which must fulfill the following criteria: symptoms are primary to the disease or secondary but have not responded to current treatment; interfere with the patient's capacity to accomplish normal functioning; persist during periods of clinical stability, and represent an unresolved therapeutic need. They must be measurable by clinical scales and persist, at least, six months. The Food and Drug Administration has recently considered negative symptoms as an investigation target or new treatments due to their prevalence and high negative impact in the life of the schizophrenic population. Nowadays, the current treatments available for such an entity are second generation antipshycotics and glutamatergic agents -such as d-cycloserine and glicine-, amisulpiride and seleginine, even though their efficacy is limited. Dysfunction of the human prefrontal cortex is considered to be implicated in the pathophisiology of negative symptoms. This cerebral region is essential in the regulation of emotions and cognition. Multiple neural networks begin in the prefrontal cortex and go towards other cortical association areas, to insular region, thalamic structures, basal ganglia and limbic system. It regulates dopaminergic mesencephalic activity through activating and inhibitory pathways, allowing a precise regulation of dopaminergic activity. This double modulation model of dopaminergic pathways has been recently sustained by studies which prove that extracellular dopaminergic concentration in nucleus accumbens increases or reduces after a high or low frequency stimulation of the prefrontal cortex, respectively. A prefrontal cortex lesion causes a syndrome similar to the negative symptomathology in schizophrenia. Transcraneal magnetic stimulation (TMS) could be effective in the treatment of negative symptoms by activating the prefrontal cortex, maybe by stimulating the liberation of dopamine in the mesolimbic and mesoestriatal pathways which have a crucial role in the pathogenesis of negative symptoms such as apathy and anhedonia. TMS was introduced in 1985 and since the early 90's its potential as a treatment has been tested in numerous neurological and psychiatric conditions. It is a noninvasive means of stimulating nervous cells in superficial areas of the brain. During a TMS procedure, an electrical current passes through a wire coil placed over the scalp. This induces a magnetic field that can produce a substantive electrical field in the brain. This electrical field produces in turn a depolarization of nervous cells resulting in the stimulation or disruption of brain activity. TMS may be applied as a single stimulus or repeated many times per second (repetitive TMS), with variations in the intensity, site, and orientation of the magnetic field. Most research and interest has focused on the potential application of repetitive TMS (rTMS) in the treatment of depression. In addition, in recent years an increasing number of open and double-blinded studies of rTMS were conducted in patients with schizophrenia. Most investigators have chosen to focus on the treatment of specific refractory symptoms or syndromes within the disorder such as refractory auditory hallucinations or persistent negative symptoms. TMS has become widely used in research, especially as a method to probe normal and abnormal brain function, motor cortical physiology, and cognition. Regarding negative symptoms in schizophrenia, eleven studies using TMS were carried out until 2006, with a total of 172 patients studied. These studies are difficult to compare because they used different stimulation parameters and the symptoms described were heterogenic. Six studies were blind and five were open, using high frequency TMS in all of them (frequencies above 1 Hz), which is the type of stimulation most commonly used in treatment studies. Six of these studies found a reduction in the severity of the symptoms, but the reduction was not significant in two of them. Ten were the maximum number of sessions included in every study, except for one, in which 20 sessions of TMS were given. In this study, the score of negative subscale of the PANSS was reduced in 33%, which is considered a significant response, and this result was sustained within the next month. In one of these studies, researchers compared 3- and 20-Hz stimulation with sham stimulation and stimulation provided at the patient's individual alpha frequency. Alpha-frequency stimulation was calculated as the patient's peak alpha frequency from five frontal EEG leads. Stimulation of alpha frequency resulted in a significantly greater reduction in negative symptoms than the other conditions. This finding could suggest that negative symptoms may specifically relate to alpha EEG oscillations, which is interesting and requires further exploration and confirmation. Another two studies were conducted in 2007; in the first one, no improvement in negative, positive of affective symptoms was found. The second one, which was a double-blinded clinical trial, found a significant reduction in the intensity of negative, positive, and general symptoms with the active TMS. We should remark that TMS produces changes in the cortical activity in ventral and dorsoestratial regions, but other cerebral regions could be stimulated too, since some activation abnormalities in the left globus palidus, bilateral caudate nucleus, prefrontal, and temporal right cortex have been found and are associated with the etiology of the negative syndrome. In addition, it will be interesting to see whether changes in subcortical dopamine release, which were shown with rTMS in normal volunteers, can be demonstrated in clinical populations, such as patients with schizophrenia, and how this may relate to response to treatment. There is still a need for a larger number of controlled studies, with larger samples, longer periods of evaluation, and constant stimulation parameters, so they can be compared between them and the exact efficacy of TMS as a treatment for negative symptoms can be established.

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9

Vectorial chaos synchronization and polarization encoding in self-pulsating VCSELs

Danckaert, Jan; Scirè, Alessandro; Mulet, Josep; Mirasso, Claudio R.; San Miguel, Maxi
2003-06-01

Digital.CSIC (Spain)

10

Tratamiento del tinnitus en hipoacusias neurosensoriales de curvas descendentes por modulación de los neurotransmisores con el uso de acamprosato: Experiencia clínica/ Tinnitus treatment by neurotransmitter modulation in high frequency sensorineural hearing loss using Acamprosate: A clinical experience

Peña Martínez, Alejandro
2007-04-01

Resumen en español Introducción: El tinnitus neurosensorial está correlacionado con numerosas patologías del oído interno y de su vía central y que pueden originarse en cualquier nivel de ésta; sin embargo todas estas noxas pueden manifestarse igual en corteza auditiva, como una sensación auditiva sin mediar un estímulo acústico externo, de tal manera que este mensajero común deben ser los neurotransmisores. Se han descrito dos en la vía auditiva aferente: el glutamato que es exc (mas) itatorio y el GABA que es inhibitorio. Numerosos estudios revelan que el tinnitus neurosensorial se produciría por un desbalance de estos dos neurotransmisores con predominio excitatorio. El acamprosato es un fármaco usado en el alcoholismo que actuaría modulando el equilibrio GABA-glutamato. Existe un sólo estudio publicado con el uso del acamprosato en el tinnitus con una mejoría o disminución de su intensidad en 80% o más de los casos. Objetivos: Conocer la real utilidad del fármaco pues en este estudio, arriba mencionado, la evaluación fue sólo subjetiva y sin seguimiento. Material y Método: Fueron estudiados 20 pacientes tratados por un mes efectuándose tinnitumetría, evaluación psicoemocional (THI) y seguimiento. Resultados: De los 20 pacientes, en dos desapareció el tinnitus, en seis bajaron los niveles de la tinnitumetría en 5 dBo más con mejoría del THI en 50% o más y en doce pacientes la mejoría fue menor o ninguna. Conclusiones: Sería posible modular los neurotransmisores de la vía auditiva aferente con éxito, en aquellos pacientes con tinnitus severo. Es un estudio original con un respaldo fisiopatológico que abre nuevas perspectivas terapéutica Resumen en inglés Background: Sensorineural tinnitus is correlated to several inner ear and auditory pathway disorders. However noxas originating from different auditory pathway levels may be similarly manifested in the auditory cortex. A likely candidate for these shared messengers are neurotransmitters. Two neurotransmitters have been described in the afferent auditory pathways: glutamate, which is excitatory and GABA, which is inhibitory. Different studies have shown that sensorineural (mas) tinnitus is caused by an imbalance of these two neurotransmitters with an excitatory predominance. Acamprosate, a drug used in the treatment of alcoholism, might act modulating the balance glutamate-GABA. It could have a similar effect in the auditive afferent pathway. Only one research study on the use of acamprosate for tinnitus treatment has been published, which a result of over 80% of either relief or disappearance of tinnitus. Aim: To Investigate the actual usefulness of Acamprosate In tinnitus treatments, since in the previously mentioned study the results were subjectively measured, with no follow up. Methods: Twenty patients treated with Acamprosate during a period of one month were studied; tinnitus psychoacoustic and psychoemotional assessment (THI) were carried out. Results: Out of twenty patients, in two tinnitus disappeared, in six, it was reduced in 5 or more dB and in these same patients THI improved in 50% or more. In 12 patients there was a very slight improvement or no changes at all. Conclusions: It would be possible to modulate successfully the neurotransmitters of the afferent auditory pathway in some patients suffering from severe tinnitus using Acamprosate. This is an original study with physiopathological bases, which offers new therapeutic perspectives

Scientific Electronic Library Online (Spanish)

12

Switched-Current Bandpass Sigma-Delta Modulators for AM Digital Radio Receivers

Rosa Utrera, José Manuel de la; Pérez Verdú, Belén; Medeiro, Fernando; Río Fernández, Rocío del; Rodríguez Vázquez, Angel
2001-11-01

Digital.CSIC (Spain)

13

Switchable ultrastrong coupling in circuit QED

Peropadre, Borja; Forn-Díaz, Pol; Solano, Enrique; García-Ripoll, Juan José
2010-04-10

Digital.CSIC (Spain)

14

Supercontinuum generation from intense partially coherent laser beams in optical fibers

Corredera, P.; Martín-López, S.; González-Herráez, M.
2009-01-01

Digital.CSIC (Spain)

15

Simulations of fast switching between longitudinal modes of semiconductor laser cavity induced by on-chip filtered optical feedback

Ermakov, Ilya; Beri, Stefano; Boudewijn, Docter; Pozo, José; Smit, Meint; Danckaert, Jan
2009-11-01

Digital.CSIC (Spain)

16

Recuperación nutricional: Un desafío pendiente/ Catch up growth: An unresolved challenge

G Weisstaub, Sergio; Araya Q, Magdalena
2003-02-01

Resumen en inglés Factors that modulate catch up growth influence the quantity and quality of the recovered tissue. Insulin and IGF-1 respond to dietary changes in carbohydrates and proteins; evidence shows that IGF-1 and leptin may be good indicators of nutritional recovery. The optimal diet to promote catch up growth is still controversial. There is consensus on the need to adjust the energy-protein intake to the growth velocity observed, without encouraging excessive eating, to avoid ob (mas) esity. Zinc supplementation and physical activity appear as relevant factors to promote the synthesis of lean mass. In some models of early malnutrition, a better catch up growth during childhood, is associated with a higher frequency of chronic diseases and mortality in adulthood. In this context, we will review some factors that seem relevant to the modulation of catch up growth, which should be taken into account when reviewing the therapeutic guidelines to treat malnourished children (Rev Méd Chile 2003; 131: 213-9)

Scientific Electronic Library Online (Spanish)

17

Propagation and localization of electromagnetic waves in quasiperiodic serial loop structures

Aynaou, H.; El Boudouti, E. H.; Velasco, V. R.; El Hassouani, Y.; Akjouj, A.; Djafari-Rouhani, B.; Vasseur, J.; Benomar, A.
2005-11-03

Digital.CSIC (Spain)

18

Practical Study of Idle Tones in 2nd-Order Bandpass Sigma-Delta Modulators

Rosa Utrera, José Manuel de la; Pérez Verdú, Belén; Medeiro, Fernando; Río Fernández, Rocío del; Rodríguez Vázquez, Angel

This paper studies the tonal behaviour of the quantization noise in 2nd-order bandpass Sigma-Delta modulators. Closed-form expressions for the frequency of the idle tones are derived for different locations of the signal centre frequency. The analytical results are validated through experimental mea...

DRIVER (Spanish)

19

Practical Study of Idle Tones in 2nd-Order Bandpass Sigma-Delta Modulators

Rosa Utrera, José Manuel de la; Pérez Verdú, Belén; Medeiro, Fernando; Río Fernández, Rocío del; Rodríguez Vázquez, Angel
2002-11-01

Digital.CSIC (Spain)

20

Polarization message encoding through vectorial chaos synchronization in vertical-cavity surface-emiting lasers

Scirè, Alessandro; Mulet, Josep; Mirasso, Claudio R.; Danckaert, Jan; San Miguel, Maxi
2003-03-18

Digital.CSIC (Spain)

21

Photothermal excitation of microcantilevers in liquids

Ramos Vega, Daniel; Tamayo, Javier; Mertens, Johann; Calleja, Montserrat
2006-06-21

Digital.CSIC (Spain)

23

Periodic entrainment of power dropouts in mutually coupled semiconductor lasers

Buldú, Javier M.; Vicente, Raúl; Pérez, Toni; Mirasso, Claudio R.; Torrent, M. C.; García-Ojalvo, Jordi
2002-12-30

Digital.CSIC (Spain)

24

Optical waveguide cantilever actuated by light

Zinoviev, Kirill; Domínguez, Carlos; Plaza, José Antonio; Lechuga, Laura M.
2008-01-04

Digital.CSIC (Spain)

25

Optical aberrations in the mouse eye

García de la Cera, Elena; Rodríguez, Guadalupe; Llorente, Lourdes; Schaeffel, Frank; Marcos, Susana
2006-03-03

Digital.CSIC (Spain)

26

Optical Modulation Transfer and Constrast Sensitivity with Decentered Small Pupils in the Human Eye

Artal, Pablo; Marcos, Susana; Iglesias, Ignacio; Green, Daniel G.
1996-11-01

Digital.CSIC (Spain)

27
29

Non-uniform strain relaxation in InxGa1−xAs layers

Alvarez, A. L.; Muñoz Sandoval, E.; García, Rafael; González, Luisa; González, Yolanda; Kidd, P.; Goodhew, P. J.
1996-01-01

Digital.CSIC (Spain)

30

Non-Ideal Quantization Noise Shaping in Switched-Current Bandpass Sigma-Delta Modulators

Rosa Utrera, José Manuel de la; Pérez Verdú, Belén; Medeiro, Fernando; Río Fernández, Rocío del; Rodríguez Vázquez, Angel
1999-05-01

Digital.CSIC (Spain)

31

Non linear down-frequency conversion effects in high intensity Vibration of plate transducers and piezoelectric structures

Alippi, Adriano; Bettucci, Andrea; Biagioni, Angelo; Gallego Juárez, Juan Antonio; Passeri, Daniele; Riera, Enrique
2007-12-01

Digital.CSIC (Spain)

36

Kainate Receptors Presynaptically Downregulate GABAergic Inhibition in the Rat Hippocampus

Rodríguez-Moreno, Antonio; Herreras, Óscar; Lerma Gómez, Juan
1997-10-01

Digital.CSIC (Spain)

37
38

Impacto de la apolipoproteína A5 en el riesgo cardiovascular: Modulaciones genéticas y ambientales/ Impact of apolipoprotein A5 on cardiovascular risk: Genetic and environmental modulation

SOTOS-PRIETO, MERCEDES; FRANCÉS, FRANCESC; CORELLA, DOLORES
2010-07-01

Resumen en inglés Triglyceride concentrations are an independent risk factor for coronary heart disease. Apolipoprotein A5 gene (APOA5) has an important role determining triglyceride metabolism and it is a potential cardiovascular risk. However the mechanisms for these actions are not well-known. Despite the different allelic frequency of its major polymorphisms in different populations, multiple studies have shown consistent associations between these variants and fasting triglycerides. V (mas) ariations in the APOA5 gene have also been associated with postprandial triglycerides, as well as with different sizes of lipoproteins and other markers. Moreover, some of the APOA5 gene variants have been associated with ischemic heart disease, stroke, and carotid intima media thickness, although the references on this issue are scanty and contradictory. This may be due to the presence of gene-environment interactions that have been poorly studied until now. Among the few studies that have examined the infuence of environmental factors on possible genetic variations, the most important are those that contemplate possible gene-diet interactions. However, the evidence is still scarce and more research is required in the feld of nutrigenomics. To understand the impact of this gene on cardiovascular disease, we review the genetic functionality and variability of APOA5, its associations with intermediate and fnal phenotypes and gene-environment interactions detected

Scientific Electronic Library Online (Spanish)

39

High-Order Cascade Multi-bit ΣΔ Modulators for High-Speed A/D Conversion

Río Fernández, Rocío del; Medeiro, Fernando; Pérez Verdú, Belén; Rodríguez Vázquez, Angel

DRIVER (Spanish)

40

High-Order Cascade Multi-bit ΣΔ Modulators for High-Speed A/D Conversion

Río Fernández, Rocío del; Medeiro, Fernando; Pérez Verdú, Belén; Rodríguez Vázquez, Angel
1998-11-01

Digital.CSIC (Spain)

41

Ghost resonance in a semiconductor laser with optical feedback

Buldú, Javier M.; Chialvo, Dante R.; Mirasso, Claudio R.; Torrent, M. C.; García-Ojalvo, Jordi
2003-02-03

Digital.CSIC (Spain)

42

Generación de supercontinuo en fibras ópticas monomodo con fuentes de bombeo continuo

Corredera Guillén, Pedro; González Herráez, Miguel; Martín López, Sonia
2006-06-01

Digital.CSIC (Spain)

43

Fuente supercontinua en fibra óptica (basada en bombeo continuo)

Martín López, Sonia; González Herráez, Miguel; Corredera Guillén, Pedro; Carrasco Sanz, Ana; Hernanz, María Luisa; Abrardi, Laura
2006-06-01

Digital.CSIC (Spain)

44

Frontiers of CMOS Sigma-Delta Converters - Part2: Continuout-Time Sigma-Delta Converters

Rodríguez Vázquez, Angel; Rosa Utrera, José Manuel de la
2005-01-01

Digital.CSIC (Spain)

45

Frequency response of an atomic force microscope in liquids and air: Magnetic versus acoustic excitation

Herruzo, Elena T.; García García, Ricardo

We discuss the dynamics of an amplitude modulation atomic force microscope in different environments such as water and air. Experiments, analytical expressions, and numerical simulations show that the resonance curves depend on the excitation method used to drive the cantilever, either mechanical or...

DRIVER (Spanish)

47

Experimental study of high frequency stochastic resonance in Chua circuits

Gomes, Iacyel; Mirasso, Claudio R.; Toral, Raúl; Calvo, Óscar
2003-06-26

Digital.CSIC (Spain)

48

Experimental Evidence of Stochastic Resonance in an Excitable Optical System

Marino, Francesco; Giudici, Massimo; Barland, Stéphane; Balle, Salvador
2002-01-10

Digital.CSIC (Spain)

49

Experimental Characterization of IdleTones in Second-Order Bandpass ΣΔ Modulators

Rosa Utrera, José Manuel de la; Pérez Verdú, Belén; Medeiro, Fernando; Río Fernández, Rocío del; Rodríguez Vázquez, Angel
2000-11-01

Digital.CSIC (Spain)

50

Entrainment of optical low-frequency fluctuations is enhanced by coupling

Buldú, Javier M.; García-Ojalvo, Jordi; Torrent, M. C.; Vicente, Raúl; Pérez, Toni; Mirasso, Claudio R.

10 pages, 7 figures.-- Full-text version available Open Access at: http://www-fen.upc.es/users/ojalvo/papers/elff.pdf | The control of the low-frequency fluctuations exhibited by two mutually coupled semiconductor lasers is studied experimentally and numerically. We observe that coupling enhances th...

DRIVER (Spanish)

51

Entrainment of optical low-frequency fluctuations is enhanced by coupling

Buldú, Javier M.; García-Ojalvo, Jordi; Torrent, M. C.; Vicente, Raúl; Pérez, Toni; Mirasso, Claudio R.
2003-03-05

Digital.CSIC (Spain)

52

El convertidor matricial en aplicaciones de conversión CA-CA trifásicas: métodos escalares y vectoriales de control/ THE MATRIX CONVERTER IN AC-AC THREE-PHASE CONVERSION APPLICATIONS: SCALAR AND VECTOR CONTROL METHODS

Lara, Jorge; Guzmán, Víctor; Cabello, Alexis; Giménez, María Isabel; Restrepo, José
2008-01-01

Resumen en español Este trabajo muestra las características de operación de un convertidor matricial (CM) empleado en conversión CA-CA trifásica, operado con control escalar y con control vectorial del voltaje de salida. La conversión directa CA-CA por medio de convertidores matriciales permite modular la tensión, frecuencia y fase del sistema eléctrico trifásico a objeto de controlar el comportamiento de la carga, y permitir la regeneración de energía de la carga a la alimentaci� (mas) �n principal. Con un control adecuado, esta configuración puede ser más versátil que el sistema tradicional de conversión CA-CA indirecta, formado por la conexión en cascada de un conversor AC-DC, usualmente no controlado, y un conversor DC-AC tipo inversor trifásico. Los convertidores matriciales son complejos debido a que su matriz de conmutación usa dieciocho interruptores unidireccionales y cada conmutación es crítica. En este trabajo se consideran cuatro métodos de control escalar y un método de control vectorial. Los algoritmos de control se prueban mediante simulación digital en una PC en Matlab y a continuación se aplican experimentalmente, utilizando plataforma de desarrollo basada en el procesador digital de señales AD-21364 de Analog Devices. Resumen en inglés This paper offers the operational characteristics of the matrix converter (MC) used in AC-AC conversion operated with a scalar control and with a vector control of the outlet voltage. Direct AC-AC conversion using matrix converters allows for the modulation of the tension, frequency and phase of the three-phase electric system in order to control the behavior of the load and account for the regeneration of power of the load to the main supply. With an adequate control thi (mas) s configuration may be more versatile than the traditional indirect AC-AC conversion system formed by the cascade connection of a usually uncontrolled AC-AC converter and a three-phase DC-AC inverter-type converter. The matrix converters are complex since their commutation matrix uses eighteen unidirectional switches, and each commutation is critical. This work considers four scalar control methods and one vector control method. The control algorithms are tested through digital simulation in a PC in Matlab and then are experimentally applied using a development platform based on the AD-21364 signal digital processor of Analog Devices.

Scientific Electronic Library Online (Spanish)

53

Effects of interactions among wave aberrations on optical image quality

McLellan, J. S.; Prieto, P. M.; Marcos, Susana; Burns, Stephen A.
2006-05-12

Digital.CSIC (Spain)

54

Effect of Clock Jitter Error on the Performance Degradation of Multi-bit Continuous-Time ΣΔ Modulators With NRZ DAC

Tortosa, Ramón; Rosa Utrera, José Manuel de la; Rodríguez Vázquez, Angel; Fernández, Francisco V.
2005-11-01

Digital.CSIC (Spain)

55

Drifting instabilities of cavity solitons in vertical-cavity surface-emitting lasers with frequency-selective feedback

Paulau, P. V.; Gomila, D.; Colet, Pere; Matías, Manuel A.; Loiko, N. A.; Firth, W. J.
2009-08-12

Digital.CSIC (Spain)

56

Digital read-out integrated circuit for the digital reading of high-speed image sensors

Serra Graells, Francisco; Margarit Taule, Josep M.; Teres Teres, Lluis
2009-11-19

Digital.CSIC (Spain)

57

Diffusive turn-off transients in current modulated multitransverse mode VCSELs

Valle, Angel; Mulet, Josep; Pesquera, Luis; Balle, Salvador
2002-06-01

Digital.CSIC (Spain)

60

Clock Jitter Error in Multi-bit Continuous-Time Sigma-Delta Modulators with Non-Return-to-Zero Feedback Waveform

Tortosa, Ramón; Rosa Utrera, José Manuel de la; Fernández, Francisco V.; Rodríguez Vázquez, Angel
2008-01-01

Digital.CSIC (Spain)

61

Chaotic breathers in delayed electro-optical systems

Chembo Kouomou, Yanne; Colet, Pere; Larger, Laurent; Gastaud, Nicolas
2005-11-09

Digital.CSIC (Spain)

62

CMOS Fully-Differential BandPass Sigma-Delta Modulator Using Switched-Current Circuits

Rosa Utrera, José Manuel de la; Pérez Verdú, Belén; Medeiro, Fernando; Rodríguez Vázquez, Angel
1996-02-01

Digital.CSIC (Spain)

63

Asociación entre el perfil sensorial, el funcionamiento de la relación cuidador-niño y el desarrollo psicomotor a los tres años de edad/ Association between the sensory profile, the quality of the infant-parent relationship and the child development, at three years of age

Castillejos-Zenteno, Liliana; Rivera-González, Rolando
2009-06-01

Resumen en español Con la intención de complementar los criterios del DSM-IV, en el caso de los niños pequeños, el Zero to Three/Centro Nacional para Programas Clínicos para Infantes, desarrolló la Clasificación Diagnóstica para los niños de cero a tres años (DC: O-3). El DC: 0-3, constó de cinco ejes. El eje I se refiere al diagnóstico primario, e incluyó los trastornos regulatorios y los trastornos del desarrollo que influyen en diferentes sistemas. Los trastornos regulatorios (mas) son de naturaleza constitucional y de maduración, basados en problemas sensoriales, sensoriomotores o de procesamiento; se caracterizan por dificultades que presenta el niño para regular su comportamiento sensorial, atencional, motor y/o afectivo, así como para organizar estados afectivos positivos, de alerta o acciones para calmarse. El objetivo de la presente investigación fue establecer la asociación entre las características del perfil sensorial con el desarrollo psicomotor del niño. Metodología Para valorar el nivel de desarrollo de los niños se utilizó el Perfil de Conductas de Desarrollo, en su versión revisada (PCD-R). Para reconocer un trastorno regulatorio se utilizó el Sensory Profile que valora el procesamiento sensorial del niño y su repercusión en la vida cotidiana. También analizó el nivel de funcionamiento de la relación cuidador-niño con la escala Parent-Infant Relationship Global Assessment Scale (PIR-GAS) del DC: 0-3. Resultados Los niños tuvieron una edad de 43.2+4.2 meses, 50% fueron niñas, el desarrollo mostró coeficientes aproximados de 105+15 puntos y fueron más altos en las niñas que en los niños en todas las áreas excepto habilidad manual, con diferencias significativas en lenguaje expresivo, alimentación y praxis. De manera global el Perfil Sensorial (SP) mostró 17 niños (31 %) con perfil sensorial >; 21 (39%) con sospecha y 16 (30%) en el grupo de >. La relación de trastornos regulatorios entre niños y niñas se dio en una razón de 3:1. Las secciones >, >, > y > presentaron mayor frecuencia de perfiles de los niños por fuera del comportamiento típico (50%). Los factores > e > fueron los más afectados con más del 50% de casos por fuera del rango típico. Todas las áreas del PCD-R tuvieron algún grado de correlación al menos con dos secciones del SP, siendo las áreas emocional/ social y lenguaje expresivo del PCD-R las que mostraron mayor número de correlaciones significativas con las secciones y factores del SP. Las secciones de > y >, fueron las que se correlacionaron con la mayoría de áreas del PCD-R. En el análisis de varianza entre los resultados globales del SP y las medias de los coeficientes del desarrollo mostró diferencias significativas en seis de las nueve áreas evaluadas. La relación cuidador-niño valorada con la escala (PIR-GAS) del DC: 0-3, mostró relación adaptada en 20 casos (37%), relación levemente afectada en 15 casos (28%) y relación disfuncional en 19 casos (35%), no se observó asociación entre los coeficientes del desarrollo del PCD-R según estos tres grupos de funcionamiento de la relación. Mediante análisis de correspondencia se corroboró que a mayor afectación del perfil sensorial, mayor alteración en la relación cuidador-niño. Las diferencias en la integración de estímulos sensoriales, cuando impactan en la vida cotidiana de los niños, guardan una asociación con el desarrollo en diferentes áreas. El funcionamiento de la relación cuidador-niño no fue una variable que modificase el efecto de la asociación entre el perfil sensorial y el desarrollo, ya que no mostró relaciones con el desarrollo psicomotor, pero sí con el perfil sensorial del niño. Resumen en inglés Since the beginning of the last century there were some differences in child-related difficulties in regulation that could not be included in the categories of diagnosis were counted, so they fitted within the learning problems, coordination problems and sometimes until the epilepsy. Decades later, each problem was subject of a separate diagnostic category, which favored the study of diseases, but fragmented the diagnosis for children who had a variety of symptoms that so (mas) me of them were due to a single source. Then the diagnoses increased in coordination disorder, attention deficit disorder with and without hyperactivity (ADHD), the sensory integration dysfunction, language disorders, and so on. In order to complete the criteria of DSM-IV, in the case of children the Zero to Three/National Center for Clinical Programs for Infants developed a diagnostic classification for children from 0 to 3 years old (DC: O-3). The DC: 0-3, consists of five axes. The Axis I refers to the primary diagnosis, and includes the regulatory disorders and developmental disorders that affect different systems. Regulatory disorders are constitutional in nature, based on sensory problems, or sensorimotor processing, characterized by difficulties of the child to regulate their behavior, sensory, attention, motor and/or emotional, to organize positive affective states, warning or actions to calm down. The objective of the present research was to establish the association between the characteristics of the Sensory Profile, the parent-infant relationship and the psychomotor development of children. Materials and methods To assess the level of development of children was used the Conduct Development Profile, as revised (PCD-R). For the parent-infant relationship was used the Parent-Infant Relationship Global Assessment Scale (PIR-GAS). Thus, to recognize a regulatory disorder it was used the Sensory Profile which assess the child's sensory processing and its impact on the daily lives of children. To fit the relationship style in one of the categories, the children and their caregiver play for about 15 minutes with three types of toys, according to the classification of Florey. Statistical analysis For data analysis were conducted descriptive statistics of the general variables and those of primary interest, test Chi² for contingence tables test, correspondence analysis and comparison one-way variance analysis. Analyses conducted using SPSS 12.0 statistical software. Results The children had an average age of 43.2 ± 4.2 months, 50% were girls, development showed ratios of around 105 ± 15 points. The average ratios of development were higher in girls than in boys in all areas except manual skill. The characteristics of sensory profile were established on the basis of results obtained in the SP: 1 7 children (31 %) were located in the group with > sensory profile, which refers to the scores within the parameters of typical performance or have up to two factors with likely difference; 21 children (39%) were located in the > group when the subjects likely to exceed two factors with difference and up to 1 factor with definitive difference, and 1 6 children (30%) in the > group formed by the cases that are more than three factors likely to dispute and/ or difference with more than two final (over four factors outside of the typical performance). Sections of >, >, > and > were those that had a higher frequency of profiles of children outside typical behavior (50%). The section of > was the most frequent typical behavior among children (78%). In relation to the factors, the proportion of children who had values within the typical range in each of the factors of SP was 41 % to 83%, > and > were the most affected by having more than a half of the cases outside of the typical range, while > and > were the least altered, being over 75% of cases characterized as typical performance. At the regulatory disorders assessment boys showed more frequent regulatory disruptions, 44% respect to girls 15% (p > and > areas of the PCD-R showed more significant correlations with sections of the SP, while > and > sections, which were correlated with most of the development areas explored with the PCD-R. The variance analysis comparing the averages of development reached in the PCD-R, according to the SP results showed statistical differences between the averages in six of nine factors evaluated, being the regulatory disorder the group that makes a difference for the respect to two others. The results of the evaluation about the relationship between caregiver and child valued by the scale Parent-Infant Relationship Global Assessment Scale (PIR-GAS) DC: 0-3, did not show differences in the average ratios of development in the PCD-R among the three groups that were conducted. Nevertheless was noted that children with affected sensory profile presented problems more frequent in relation to the caregiver. Discussion Data from the study population showed values close to those reported by the respective instruments, discreetly above the expected variance similar to that described in the standardized tests. In the most of the development areas, the group of girls had the highest averages ratios. This results are similar with that are described in the literature. We also found an increased frequency of regulatory disorders in boys, 3:1 or 2:1, which could be related with by patterns of socialization. Respect the parent-infant relationship there not found differences that affect significantly the child development, evaluated with the PCD-R, unless when the relatioship was significantly affected. Differences in integrating sensory stimuli, when impact the daily life of children are related to development in different areas. The functioning of the parent-infant relationship was not a variable that changed the effect of the association between sensory profile and development, as it showed no relations with psychomotor development, but shows relations with the sensory profile of the child. In conclusion, differences in the integration of sensory stimuli, when impacting on the daily lives of children at three years old, have an association with the development so that there are areas of development that appear to be more sensitive than others in a any child who presents regulatory disorder. The functioning of the mother-child relationship showed no relations with psychomotor development, however it did with the sensory profile of the child.

Scientific Electronic Library Online (Spanish)

64

Análisis del campo electromagnético en Ciudad de La Habana

Hernández Escrivá, Jesarely; Barceló Pérez, Carlos
1996-08-01

Resumen en español Con el objetivo de valorar la exposición de la población al campo electromagnético, a cuenta de las transmisiones civiles en Ciudad de La Habana, se efectuaron los cálculos teóricos de propagación de ondas en la gama de frecuencias medias, cortas y ultracortas en modulaciones de amplitud, frecuencia y pulso, y se obtuvieron estimaciones de las zonas de protección sanitaria y límite de construcción a partir de normas europeas para los transmisores instalados que o (mas) peraban a su máxima capacidad. Con la técnica de reconocimiento de patrones se observó que el riesgo sanitario era de igual modo mayor en los transmisores de televisión del oeste de la ciudad, en los emisores de frecuencia modulada del centro y en una de las frecuencias de radar del este de la ciudad, se hallaron múltiples edificaciones civiles en áreas de presunta restricción. El riesgo sería mínimo en las emisiones de ondas medias. Los valores que resultan de la situación real y los valores medidos indican que en ningún momento llega a transgredirse el nivel permisible de campo para la salud humana. El cálculo teórico de los campos asociados a las líneas de alta tensión que se hallan en zonas aledañas y dentro de la ciudad delimita una extensión de la zona de protección sanitaria del orden hasta de las centenas de metros. Resumen en inglés Theoretical calculations of the propagation of waves in the range of medium, short and ultrashort frequencies in modulation of amplitude, frequency and pulse were made aimed at assesing the popula-tion's exposure to the electromagnetic field as a result of civil broadcastings in Havana City. Estimations of the sanitary protection zones and construction limits were obteined from European standards for installed transmiters operating at their maximum capacity. By using the (mas) patterns recognition technique it was observed that the sanitary risk was greater in the television transmitters from the western part of the city, in the broadcastings of modulated frequency from the center, and in one of the radar frequencies from the eastern part of the city. Multiple civil buildings were found in the alleged restriction areas. The risk was minimun in the medium wave broadcastings. The values resulting from the real situation, as well measured values show that the permissible level for human health is never transgressed. The theoretical calculation of the fields associated to the high voltage lines located at the pearly zones and in the city delimits an extension of the sanitary protection zone of hundreds of meters.

Scientific Electronic Library Online (Spanish)

65

Análisis de los límites de exposición humana a campos electromagnéticos de acuerdo a la norma UIT-K.52 para frecuencias entre 10 kHz y 3 GHz en áreas urbanas de Bucaramanga/ limits for human exposure to electromagnetic fields in accordance with ITU- k.52 standard for frequencies between 10 khz and 3 GHz in urban areas of Bucaramanga

Rugeles Uribe, José de Jesús; Jaimes Oviedo, Antonio; Sánchez Barón, Víctor Hugo; Mantilla Prada, Óscar Alberto; Sastoque Gálvez, Eduard
2007-12-01

Resumen en español Este artículo presenta una descripción de los resultados alcanzados en la comprobación de los límites de exposición humana para el rango de frecuencias de 10KHz hasta 3GHZ en la ciudad de Bucaramanga (Colombia) teniendo en cuenta las disposiciones del Decreto 195 2005, aprobado por el Ministerio de Comunicaciones, basado en la recomendación K.52 de la Unión Internacional de Telecomunicaciones (UIT). Fue posible comprobar, mediante una campaña de medidas, que los n (mas) iveles de exposición a radiaciones electromagnéticas obtenidas en tres lugares de la ciudad considerados sensibles no superaron en ninguno de los casos los límites de exposición. Se consideraron, además de las bandas de telefonía móvil, emisiones de amplitud modulada, frecuencia modulada y televisión, instaladas en los sitios de medida desde hace varios años. En todos los casos los niveles obtenidos de intensidad de campo eléctrico superaron los 100 dBuV/m, con un valor máximo de de 139 dBuV/m, niveles que están muy por debajo de los límites de exposición establecidos por la norma K-52. Los niveles más altos para la exposición de público general fueron 1,74964. % en la banda de AM y 0,006408 % para la banda de celular entre 869 y 894 MHZ. Se presenta además una descripción de los módulos: límites de exposición, adquisición y georreferenciación, implementados en la herramienta EspecVIEW, diseñada para realizar diversos tipos de campañas de medida por parte de los funcionarios del ministerio y empleada en este estudio. Resumen en inglés This article presents an overview of the results obtained from testing the limits of human exposure to 10KHz to 3GHZ frequencies in the city of Bucaramanga (Colombia), taking into account decree 195-2005 approved by the Colombian Ministry of Communications, based on International Telecommunication Union (ITU) recommendation K.52. Measuring levels of exposure to electromagnetic radiation at three chosen locations in the city considered to be sensitive did not reveal that e (mas) xposure limits were being exceeded. Mobile phone, modulated amplitude emission, frequency modulation and television bands installed at the sites several years ago were also measured. Levels obtained from electric field strength exceeded 100 dBuV / m in all cases, maximum value being 139 dBuV / m. Levels were well below exposure limits established by the K-52 rule. The highest levels for the general public’s exposure were 1.74964% in the AM band and 0.006408% for the cellular band between 869 and 894 MHz. This article also contains a description of the modules, exposure limits, acquisition and geo-positioning using the EspecVIEW tool designed for performing several types of measurements by Ministry officials and used in this study.

Scientific Electronic Library Online (Spanish)

66

Analysis of Error Mechanisms in Switched-Current Sigma-Delta Modulators

Rosa Utrera, José Manuel de la; Pérez Verdú, Belén; Medeiro, Fernando; Río Fernández, Rocío del; Rodríguez Vázquez, Angel
2004-01-01

Digital.CSIC (Spain)

67

Analysis and Experimental Characterization of Idle Tones in 2nd-Order Bandpass Sigma-Delta Modulators - A 0.8μm CMOS Switched-Current Case Study

Rosa Utrera, José Manuel de la; Pérez Verdú, Belén; Medeiro, Fernando; Río Fernández, Rocío del; Rodríguez Vázquez, Angel
2001-05-01

Digital.CSIC (Spain)

70

A NEW TECHNIQUE OF MEASURING LOW‐POWER PICOSECOND OPTICAL PULSE TRAINS

Muñoz Zurita, Ana Luz; Shcherbakov, Alexandre S.; Campos Acosta, Joaquín; Gómez Jiménez, Ramón
2009-01-01

Digital.CSIC (Spain)

71

A Fourth-Order BandPass Sigma-Delta Modulator Using Current-Mode Analog/Digital Circuits

Rosa Utrera, José Manuel de la; Pérez Verdú, Belén; Medeiro, Fernando; Rodríguez Vázquez, Angel
1996-06-01

Digital.CSIC (Spain)

72

A CMOS Fully-Differential Bandpass ΣΔ Modulator Using Switched-Current Circuits

Rosa Utrera, José Manuel de la; Medeiro, Fernando; Pérez Verdú, Belén; Rodríguez Vázquez, Angel
1995-08-01

Digital.CSIC (Spain)

73

A CMOS 0.8μm Transistor-Only 1.63MHz Switched-Current Bandpass ΣΔ Modulator for AM Signal A/D Conversion

Rosa Utrera, José Manuel de la; Pérez Verdú, Belén; Río Fernández, Rocío del; Rodríguez Vázquez, Angel
2000-08-01

Digital.CSIC (Spain)

74

A CMOS 0.8μm Fully Differential Current Mode Buffer For HF SI Circuits

Rosa Utrera, José Manuel de la; Pérez Verdú, Belén; Medeiro, Fernando; Domínguez Castro, Rafael; Rodríguez Vázquez, Angel
1998-11-01

Digital.CSIC (Spain)

75

A BIST Solution for Frequency Domain Characterization of Analog Circuits

Barragán, Manuel J.; Vázquez, Diego; Rueda, Adoración
2010-01-01

Digital.CSIC (Spain)

76

A 2.5MHz 55dB Switched-Current BandPass ΣΔ Modulator for AM Signal Conversion.

Rosa Utrera, José Manuel de la; Pérez Verdú, Belén; Medeiro, Fernando; Rodríguez Vázquez, Angel
1997-09-01

Digital.CSIC (Spain)