Comprehensive analysis of correlation coefficients estimated from pooling heterogeneous microarray data

Background The synthesis of information across microarray studies has been performed by combining statistical results of individual studies (as in a mosaic), or by combining data from multiple studies into a large pool to be analyzed as a single data set (as in a melting pot of data). Specific issues relating to data heterogeneity across microarray studies, such as differences within and between labs or differences among experimental conditions, could lead to equivocal results in a melting pot approach. Results We applied statistical theory to determine the specific effect of different means and heteroskedasticity across 19 groups of microarray data on the sign and magnitude of gene-to-gene Pearson correlation coefficients obtained from the pool of 19 groups. We quantified the biases of the pooled coefficients and compared them to the biases of correlations estimated by an effect-size model. Mean differences across the 19 groups were the main factor determining the magnitude and sign of the pooled coefficients, which showed largest values of bias as they approached ±1. Only heteroskedasticity across the pool of 19 groups resulted in less efficient estimations of correlations than did a classical meta-analysis approach of combining correlation coefficients. These results were corroborated by simulation studies involving either mean differences or heteroskedasticity across a pool of N \u3e 2 groups. Conclusions The combination of statistical results is best suited for synthesizing the correlation between expression profiles of a gene pair across several microarray studies

Programa de estimulación prenatal: base para el desarrollo motor de los neonatos del hospital ESSALUD de Tarapoto

The main objective of the study was to determine if the Prenatal Stimulation Program significantly influences the motor development of the newborns of the Hospital Essalud Tarapoto, for this two samples were taken, M1 = 25 newborns, sample without the Prenatal Stimulation Program of their mothers and M2 = 25 newborns, sample with the Prenatal Stimulation Program of their mothers. Non-probabilistic sampling was used at the discretion of the researchers and a quasi-experimental design was applied; To respond to our research problem, does the Prenatal Stimulation Program significantly influence the motor development of neonates at the Essalud Tarapoto Hospital? the T-Student proportion difference test was used at 95% confidence, as well as the characteristics of the dimensions through statistical analysis. After performing the rigorous statistical tests, the alternative hypothesis was accepted; The Prenatal Stimulation Program significantly influences the Motor Development of neonates at Essalud Tarapoto Hospital, with 95% confidence; as well as the characteristics by number of babies and percentages of the dimensions in the evaluative scale were determined; Developmental Disorder, Normal Development, and Developmental Advancement in Neonates.El estudio tuvo como objetivo principal determinar si el Programa de Estimulación Prenatal influye significativamente en el desarrollo motor de los neonatos del Hospital Essalud Tarapoto, para ello se tomó dos muestras, M1 = 25 neonatos, muestra sin el Programa de Estimulación Prenatal de sus madres y M2 = 25 neonatos, muestra con el Programa de Estimulación Prenatal de sus madres. Se empleó el muestreo no probabilístico a criterio de los investigadores y se aplicó un diseño cuasi experimental; para dar respuesta a nuestro problema de investigación ¿El Programa de Estimulación Prenatal, influye significativamente en el desarrollo motor de los neonatos del Hospital Essalud Tarapoto? se usó la prueba de diferencia de proporciones T- Student al 95% de confianza, así como se describió las características de las dimensiones a través del análisis estadístico. Luego de realizar las pruebas estadísticas de rigor se aceptó la hipótesis alternativa; El Programa de Estimulación Prenatal influye significativamente en el Desarrollo Motor de los neonatos del Hospital Essalud Tarapoto, con un 95% de confianza; así como se determinó las características por número de bebés y porcentajes de las dimensiones en la escala valorativa; Trastorno del desarrollo, Desarrollo normal y Adelanto del desarrollo en los neonatos