Juan José Egozcue

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The use of chromosome specific DNA probes labelled with fluorochromes and especially the combination of several probes has been used to indirectly study the chromosome constitution of decondensed sperm nuclei by fluorescence in-situ hybridization (FISH), and has allowed to include this test in the protocol of study of infertile males. Still, if the test is(More)
In the life sciences, many measurement methods yield only the relative abundances of different components in a sample. With such relative-or compositional-data, differential expression needs careful interpretation, and correlation-a statistical workhorse for analyzing pairwise relationships-is an inappropriate measure of association. Using yeast gene(More)
  • J J Egozcue, J Daunis-I-Estadella, V Pawlowsky-Glahn, K Hron, P Filzmoser, Juan José Egozcue +4 others
  • 2011
Regression models with compositional response have been studied from the beginning of the log-ratio approach for analysing compositional data. These early approaches suggested the statistical hypothesis of logistic-normality of the compositional residuals to test the model and its coefficients. Also, the Dirichlet distribution has been proposed as an(More)
Freezing of embryos deprived of the zona pellucida (ZP) decreases their survival rate immediately after thawing, and gives rise to the separation of their blastomeres in a high percentage of cases. We have studied the ultrastructure and the characteristics of actin fibers in the cell-to-cell contact region in mouse embryos frozen-thawed without the ZP at(More)
Tissue analysis is commonly used in ecology and agronomy to portray plant nutrient signatures. Nutrient concentration data, or ionomes, belongs to the compositional data class, i.e., multivariate data that are proportions of some whole, hence carrying important numerical properties. Statistics computed across raw or ordinary log-transformed nutrient data(More)
Synaptonemal complex (SC) analysis is a widely used method for assessing the effects of genotoxic agents in germ cells. Although the evolution of the SCs and their related annexed structures, such as nucleoli, has been well established, sometimes it is difficult to assess whether the abnormal features observed correspond to genotoxic effects or to an(More)
In a scanning microscopy study of mouse oocytes from immature, young, and aged females and of oocytes aged in vivo or in vitro, we have observed four types of zona pellucida, which we classify as types A, B, C, and D. Oocyte aging gives rise to a significant increase in predegenerative (type C) oocytes; this type of zona pellucida surface could result from(More)
The use of FISH (fluorescent in situ hybridization) in decondensed sperm nuclei has allowed, during the last decade, to indirectly study the chromosome constitution of human spermatozoa. Studies in control populations have been used to set up the basal level of aneuploidy for all human chromosomes and, based on conservative estimates, the percentage of(More)