A robust AMMI model for the analysis of genotype-by-environment data.

MOTIVATION: One of the most widely used models to analyse genotype-by-environment data is the additive main effects and multiplicative interaction (AMMI) model. Genotype-by-environment data resulting from multi-location trials are usually organized in two-way tables with genotypes in the rows and environments (location-year combinations) in the columns. The AMMI model applies singular value decomposition (SVD) to the residuals of a specific linear model, to decompose the genotype-by-environment interaction (GEI) into a sum of multiplicative terms. However, SVD, being a least squares method, is highly sensitive to contamination and the presence of even a single outlier, if extreme, may draw the leading principal component towards itself resulting in possible misinterpretations and in turn lead to bad practical decisions. Since, as in many other real-life studies the distribution of these data is usually not normal due to the presence of outlying observations, either resulting from measurement errors or sometimes from individual intrinsic characteristics, robust SVD methods have been suggested to help overcome this handicap. RESULTS: We propose a robust generalization of the AMMI model (the R-AMMI model) that overcomes the fragility of its classical version when the data are contaminated. Here, robust statistical methods replace the classic ones to model, structure and analyse GEI. The performance of the robust extensions of the AMMI model is assessed through a Monte Carlo simulation study where several contamination schemes are considered. Applications to two real plant datasets are also presented to illustrate the benefits of the proposed methodology, which can be broadened to both animal and human genetics studies. AVAILABILITY AND IMPLEMENTATION: Source code implemented in R is available in the supplementary material under the function r-AMMI. CONTACT: paulocanas@gmail.com SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Colpocleisis para el tratamiento del prolapso de cúpula vaginal grave / Colpocleisis for the treatment ofadvanced vaginal vault prolapse

INTRODUCCIÓN: El prolapso de los órganos pélvicos (POP) es una condición cuya prevalencia aumenta con la edad. Es necesario que los cirujanos comprendan las indicaciones, riesgos, limitaciones y resultados de las varias técnicas quirúrgicas disponibles. En este artículo se aborda el tratamiento quirúrgico obliterativo del POP (colpocleisis y colpectomia) en base a la revisión de estudios. TÉCNICA: En la literatura son descritas muchas variaciones de las técnicas obliterativas. Con el objetivo de reglamentar la técnica para futuros estudios, describimos la técnica de LeFort modificada, realizada por los autores. Los métodos obliterativos tienen un tiempo operatório, morbilidad perioperatoria reducida y una tasa baja de recurrencia del prolapso. El índice de calidad de vida y satisfacción de la paciente son altos. CONCLUSIÓN: La literatura existente respecto a la colpocleisis es limitada por la calidad metodológica. Por tanto, no hay nivel de evidencia I o II, en lo que se refiere a la colpocleisis. Sin embargo, esta técnica debe hacer parte del arsenal terapéutico del cirujano en el abordaje de los prolapsos severos en mujeres mayores.

INTRODUCTION. The pelvic organ prolapse (POP) is a condition whose prevalence increases with age. Surgeons need to understand the indications, risks, constraints and results of various surgical techniques. This article is about obliterative surgical treatment of POP (colpocleisis and colpectomia) and it is based on the review of studies is discussed. TECHNICAL. In the literature are many variations of the techniques obliterative. In order to regulate the art for future study, we describe the technique of LeFort modified by the authors. The obliterative methods have operatory time, reduced perioperative morbidity and a low rate of recurrence of prolapse. The index ofquality oflife and patient satisfaction are high. CONCLUSION. The literature regarding the colpocleisis is limited by methodological quality. Therefore no evidence level I or II, in what concerns the colpocleisis. However, this technique should be part of the armamentarium of the surgeon in addressing severe prolapse in elderly women.