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 4,687 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The anthropometric somatotype is a quantitative description of body shape and composition. Familial studies indicate the existence of a familial resemblance for this phenotype and they suggest a substantial action by genetic factors on this aggregation. The aim of this study is to examine the degree of familial resemblance of the somatotype components and of a factor of shape, in a sample of Biscay nuclear families (Basque Country, Spain). One thousand three hundred and thirty nuclear families were analysed. The anthropometric somatotype components [Carter, J.E.L., Heath, B.H., 1990. Somatotyping. Development and applications. Cambridge University Press, Cambridge, p. 503] were computed. Each component was fitted for the other two through a stepwise multiple regression, and also fitted through the LMS method [Cole, T., 1988. Fitting smoothed centile curves to reference data. J. Roy. Stat. Soc. 151, 385-418] in order to eliminate the age, sex and generation effects. The three raw components were introduced in a PCA from which a shape factor (PC1) was extracted for each generation. The correlations analysis was performed with the SEGPATH package [Province, M.A., Rao, D.C., 1995. General purpose model and computer programme for combined segregation and path analysis (SEGPATH): automatically creating computer from symbolic language model specifications. Genet. Epidemiol. 12, 203-219]. A general model of transmission and nine reduced models were tested. Maximal heritability was estimated with the formula of [Rice, T., Warwick, D.E., Gagnon, J., Bouchard, C., Leon, A.S., Skinner, J.S., Wilmore, J.H., Rao, D.C., 1997. Familial resemblance for body composition measures: the HERITAGE family study. Obes. Res. 5, 557-562]. The correlations were higher between offspring than in parents and offspring and a significant resemblance between mating partners existed. Maximum heritabilities were 55%, 52% and 46% for endomorphy, mesomorphy and ectomorphy, respectively, and 52% for PC1. In conclusion, the somatotype presents a moderate degree of familial aggregation. For the somatotype components, as well as for PC1, the degree of familial resemblance depends on age. The sex only has a significant effect on ectomorphy.
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PMID:Heritability of the somatotype components in Biscay families. 1757 Mar 68

The aim of the present study was to examine the heritability of 11 traits in a mixed-longitudinal sample of Indian siblings, and to determine whether heritability estimates vary during the growth period and whether they are influenced by sex. The sample consisted of 245 brothers and 213 sisters from 138 nuclear families living in a semi-urban area in Kolkata, India. The age ranged between 5 and 19 years. The traits were standardised for age and sex using standard deviation scores (SDS) produced by the LMS method (Cole, T.J., 1988. Fitting smoothed centile curves to reference data. J. R. Stat. Soc. A 151, 385-418). The standard deviation scores were analysed by PCA. The two factors with eigenvalues above 1 explained 77.3% of the variance; they showed a high level of pleiotropism present among the studied traits and represented body lengths (PC1) and body weight and breadths (PC2). The heritability between all types of siblings (irrespective of sex) for the PC1 and PC2 was estimated. The heritability between various pairs of siblings showed variations along the whole ontogenetic period studied. During the childhood and pre-pubertal period, heritability between brothers, brother-sister pairs and any sibling pairs was mostly constant, with small and non-significant variations. All the pairs showed the lowest degree of heritability during puberty for PC1 but not for PC2, with significant changes of heritability estimates between adolescence and adulthood, in most of the analysed sibling pairs and in both PC factors. The highest heritability was generally observed at the end of the examined growth period in all pairs. A significant effect of sex on heritability was only detected for PC2 at 11 years of age.
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PMID:Multifactorial analysis of a mixed-longitudinal sample of Indian siblings: Age and sex effects on heritability. 1955 1

The traditional spectral dimension reduction methods are usually carried out by matching the reconstructed spectra to the original spectra mathematically, which will often result in reconstructed spectra of small spectral reconstruction errors but very poor colorimetric accuracy when compared with the original one. In order to minimize both the spectral and colorimetric errors more efficiently, we proposed three spectral dimension reduction methods by introducing the characteristics of human vision. The first method is VPCA, in which we apply spectral luminous efficiency function to the original spectra before reduction; The Second method (LMSPCA) uses a matrix derived from LMS cone sensitivity to weight the original spectra before reduction, and the matrix can be form by two methods, in which the L, M, S cones response offset is calculated by in two different ways: one is computed as the absolute value of each corresponding wave length offset, and the other is calculated as the square of each corresponding wave length offset. The third method is LMSPCAs, which is based on the second method LMSPCA by further applying PCA to the residual spectra. The result shows that the VPCA method produces the poorest perfomance. The two cones response weighted matrixes of LMSPCA method have similar performances by presenting better colorimetric accuracy and low spectral accuracy, while LMSPCAs method which compensates for the spectral loss of LMSPCA method can produce higher spectral and colorimetric reconstruction accuracy and color stability under different light source, and satisfies the requirements of spectral color reproduction.
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PMID:[The Research of Spectral Dimension Reduction Method Based on Human Visual Characteristics]. 2660 47