976 resultados para Hipótese de Riemann


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Introducción: Uno de los aspectos con mayor variación durante la adolescencia es el sueño, el cual se ve afectado por factores biológicos así como por los estados afectivos y emocionales. En esta etapa, los individuos establecen sus primeras relaciones sentimentales románticas, vínculos esenciales para la maduración de las relaciones sociales y psicosexuales. Este trabajo busca determinar la asociación existente entre las relaciones sentimentales románticas y sus características, con la calidad sueño percibida por los jóvenes. Metodología: Estudio realizado en una población de 1794 estudiantes de ciencias de la salud entre los 18 y 25 años de edad en Bogotá, Colombia, entre 2012 y 2013. Se obtuvo una muestra probabilística con asignación proporcional de 443 sujetos, estratificada por programa académico y sexo. Utilizando dos cuestionarios de auto reporte se exploraron las características de las relaciones sentimentales y la calidad de sueño percibida. Resultados: El 64% (IC 95%: 59,4-68,9%) de la población estudiada se encontró en una relación sentimental romántica. Estos sujetos tuvieron latencias de sueño prolongadas con menor frecuencia que quienes no tenían en una relación (p <0,05). La calidad de sueño percibida se asoció al nivel de satisfacción que tuvieron los sujetos en su relación, así como la atracción por su pareja. Rasgos obsesivos, ansiosos, temerosos y evitativos en la relación disminuyeron la calidad de sueño percibida. Conclusión: Las relaciones sentimentales románticas y sus características se asocian con la calidad de sueño percibida por los individuos. Se requieren estudios que determinen causalidad en esta asociación y definan potenciales estrategias de intervención al respecto.

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Introducción: una de las causas de pobre ganancia visual luego de un tratamiento exitoso de desprendimiento de retina, sin complicaciones, es el daño de los fotoreceptores, reflejada en una disrupción de la capa de la zona elipsoide y membrana limitante externa (MLE). En otras patologías se ha demostrado que la hiperautofluorescencia foveal se correlaciona con la integridad de la zona elipsoide y MLE y una mejor recuperación visual. Objetivos: evaluar la asociación entre la hiperautofluorescencia foveal, la integridad de la capa de la zona elipsoide y recuperación visual luego de desprendimiento de retina regmatógeno (DRR) exitosamente tratado. Evaluar la concordancia inter-evaluador de estos exámenes. Metodología: estudio de corte transversal de autofluorescencia foveal y tomografía óptica coherente macular de dominio espectral en 65 pacientes con DRR evaluados por 3 evaluadores independientes. La concordancia inter-evaluador se estudio mediante Kappa de Cohen y la asociación entre las diferentes variables mediante la prueba chi cuadrado y pruebas Z para comparación de proporciones. Resultados: La concordancia de la autofluorescencia fue razonable y la de la tomografía óptica coherente macular buena a muy buena. Sujetos que presentaron hiperautofluorescencia foveal asociada a integridad de la capa de la zona elipsoide tuvieron 20% más de posibilidad de recuperar agudeza visual final mejor a 20/50 que los que no cumplieron éstas características. Conclusión: Existe una asociación clínicamente importante entre la hiperautofluorescencia foveal, la integridad de la capa de zona elipsoide y la mejor agudeza visual final, sin embargo ésta no fue estadísticamente significativa (p=0.39)

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Ecological validity of static and intense facial expressions in emotional recognition has been questioned. Recent studies have recommended the use of facial stimuli more compatible to the natural conditions of social interaction, which involves motion and variations in emotional intensity. In this study, we compared the recognition of static and dynamic facial expressions of happiness, fear, anger and sadness, presented in four emotional intensities (25 %, 50 %, 75 % and 100 %). Twenty volunteers (9 women and 11 men), aged between 19 and 31 years, took part in the study. The experiment consisted of two sessions in which participants had to identify the emotion of static (photographs) and dynamic (videos) displays of facial expressions on the computer screen. The mean accuracy was submitted to an Anova for repeated measures of model: 2 sexes x [2 conditions x 4 expressions x 4 intensities]. We observed an advantage for the recognition of dynamic expressions of happiness and fear compared to the static stimuli (p < .05). Analysis of interactions showed that expressions with intensity of 25 % were better recognized in the dynamic condition (p < .05). The addition of motion contributes to improve recognition especially in male participants (p < .05). We concluded that the effect of the motion varies as a function of the type of emotion, intensity of the expression and sex of the participant. These results support the hypothesis that dynamic stimuli have more ecological validity and are more appropriate to the research with emotions.

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Substantial evidence now show that dyslexic readers have problems with speeded naming of visual items. Early research assumed that this was a consequence of phonological processing deficits, but recent findings have suggested that non-phonological processes may lie at the root of the association between slow naming speed and poor reading. In a set of studies conducted with Portuguese children, the performance of dyslexic readers on serial rapid naming and phonological measures was investigated. The hypothesis that rapid naming reflects an independent core deficit in dyslexia is supported: (1) some dyslexics are characterized by naming difficulties but intact phonological skills; (2) the variance in rapid naming performance predicts uniquely the variance in children’s reading skills, independently from phonological skills; (3) rapid naming and phonological processing measures are not reliably correlated. The results also uncovered greater predictive power of rapid naming, and in particularly the inter-item pause time, for high-frequency word reding than for pseudoword reading in developmental dyslexia. Our work shows that a phonological component alone cannot account for the rapid naming performance in dyslexia. Rather, naming problems may emerge from the inefficiencies in visual-orthographic processing as well as in phonological processing.

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The discussion about the freewill and determinism con- troversy in human behavior is an old one in philosophy and psychology. Despite the fact that discussions on the topic are abundant, some of its implications seem to go unnoticed by psychologists, and especially by students of psychology. We argue that to the same extent that a psychologist is far from the determinism he imposes -a priori and unnecessary-constraints on the development of psychology as a science and profession. As a result, we suggest that the adoption of determinism as a wor- king hypothesis, is an important attitude for the transformation of psychology into a more effective science and profession.

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Se ha demostrado que la proteína GAPDH se puede unir al ADN telomérico de cadena sencilla, tanto in vitro como in vivo. Por lo tanto, se ha planteado la hipótesis de que la GAPDH juega un papel importante en la protección de los telómeros, papel que podría ser compartido con la TRF2, proteína que participa en una gran variedad de funciones relacionadas con la homeostasis telomérica. Objetivo: el objetivo de este estudio fue determinar si existe una correlación entre la expresión de ambos genes en el epitelio superficial del ovario in vitro. Materiales y métodos: la expresión relativa de cada gen fue establecida mediante qRT-PCR, en cultivos primarios de células del epitelio superficial del ovario provenientes de un grupo de 22 donantes colombianas mestizas sanas. Resultados: las pruebas no paramétricas de Kendall y Spearman permitieron establecer que existe una correlación significativa entre los niveles de expresión de GAPDH y TRF2 a lo largo de la historia replicativa de los cultivos, en forma independiente de la edad de las donantes. Conclusión: nuestros resultados sugieren un efecto sinérgico entre TRF2 y GAPDH, que podría estar orientado a contrarrestar la reducción de los telómeros in vitro.

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Introdução: O câncer diferenciado de tireoide é a neoplasia endócrina mais frequente no mundo e a sua incidência cresce de forma acelerada. Pesquisaram-se a relação entre os níveis de tiroglobulina(Tg) prévia à ablação e a persistência/recorrência precoce do câncer diferenciado da tireoide. Materiais e métodos: Avaliaram-se 91 pacientes com câncer papilar de tireoide que foram submetidos à ablação pós-cirúrgica com iodo radiativo, numa clínica especializada, no período entre janeiro de 2006 e janeiro de 2010. A análise dos dados foi realizada utilizando-se SPSS 20 para Windows e a hipótese de pesquisa foi avaliada por meio de métodos próprios da estatística não paramétrica. Resultados: A doença progrediu em 20 pacientes durante o primeiro ano pós-ablaçãoe se encontrou relação significativa entre a Tg pré-ablação e o estado da doença ao final desse período (p = 0,000). No grupo de indivíduos que apresentaram progressão da doença, não foram observadas mudanças significativas entre os níveis da Tg avaliados seis e doze meses depois da ablação (p = 0,554). É importante ressaltar que os indivíduos com níveis de Tg prévia à ablação menores ou iguais a 2,7 ng/mL não apresentaram recorrência/persistência e que 80% dos casos corresponderam a indivíduos com níveis iniciais maiores a 24 ng/mL. Conclusão: Nos pacientes com câncer papilar de tireoide o nível sérico da Tg pré-ablação está relacionado com o estado da doença ao final do primeiro ano pós-ablação. A persistência/recorrência é menos frequente com níveis baixos e mais frequente com níveis altos.

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Objective: To determine the effect of ankle joint mobilization on the H reflex amplitude of thesoleus muscle in people with spasticity. Materials and methods: A quasi-experimental study withcrossover design and simple masking was conducted in 24 randomized subjects to initiate thecontrol or experimental group. Traction and rhythmic oscillation were applied for five minutesto the ankle joint. H wave amplitude changes of Hoffmann reflex (electrical equivalent of themonosynaptic spinal reflex) was assessed, stimulating the tibial nerve at the level of the poplitealfossa and recording in the soleus muscle. In each subject 12 measurements were taken: basalrate, during and after mobilization. Changes in H reflex amplitude were calculated in relationto basal measurement. For each measurement a hypothesis test was performed (Student t test).Results: In groups of patients with brain injury and incomplete spinal cord injury, a significantdifference was found between measurements of both studies, concerning variation in H reflexamplitude during the application of joint mobilization techniques, with a decrease in the experimentalgroup and an increase in the control group. In contrast, no significant differences werefound after mobilization therapy. Patients with complete spinal cord injury showed no significantdifferences in any measurements. Conclusion: We demonstrate the effectiveness of jointmobilization in the decrease of H reflex amplitude in patients with brain injury or incompletespinal cord injury during the mobilization maneuver, but no residual effect after completion ofthe trial. This research showed no evidence regarding excitability reduction in complete spinalcord injury. We suggest that therapeutic interventions to decrease muscle tone based on the jointmobilization should be reconsidered.