Now showing items 21-40 of 44

  • La Estadística: una cuestión de supervivencia 

    Gómez Melis, Guadalupe (2007-12-12)
    Audiovisual
    Open Access
    Podríamos empezar preguntándonos el porqué de este título. O mejor aún, el porqué de esta charla en el ciclo “La mujer: elemento innovador en la ciencia”, … Podríamos reflexionar sobre el significado de cada una de las ...
  • Mesa redonda: La Estadística en la Investigación Médica 

    Abraira Santos, Víctor; Cadarso, Carmen; Gómez Melis, Guadalupe; Martín Andrés, Antonio; Pita, Salvador (Institut d'Estadística de Catalunya, 2001)
    Article
    Open Access
    Este artículo es una transcripción de las conferencias dictadas en la mesa organizada en el 4º Congreso Galego de Estatistica y Investigación de Operacions que tuvo lugar en Santiago de Compostela en noviembre de 1999. Los ...
  • Multiple imputation approach for interval-censored time to HIV RNA viral rebound within a mixed effects Cox model 

    Alarcón Soto, Yovaninna; Langohr, Klaus; Fehér, C.; García Alcaide, Felipe; Gómez Melis, Guadalupe (2018-01-01)
    Article
    Open Access
    We present a method to fit a mixed effects Cox model with interval-censored data. Our proposal is based on a multiple imputation approach that uses the truncated Weibull distribution to replace the interval-censored data ...
  • Nonlinear transformation models: application to mortality of calves 

    López-Segovia, Lucas; Espinal Berenguer, Anna; Gómez Melis, Guadalupe (2010)
    Conference report
    Open Access
    We present. an appl ication of the proportional hazard-proportional hazard cure models to evalu ate the environmental and genetic factors that affect both mortality and survival up to weaning of beef calves. We usc the ...
  • Quantile estimation of the rejection distribution of food products integrating assessor values and interval-censored consumer data 

    Langohr, Klaus; Gómez Melis, Guadalupe; Hough, Guillermo (2013-12)
    Article
    Restricted access - publisher's policy
    Fitting parametric survival models with interval-censore d data is a common task in survival analysis and implemented in many statistical software pack ages. Here, we present a novel approach to fit such models if the ...
  • Recommendations to choose the primary endpoint in cardiovascular clinical trials 

    Gómez Melis, Guadalupe; Gómez Mateu, Moisés; Dafni, Urania (2013)
    External research report
    Open Access
    Background – A composite endpoint is often used as the primary endpoint to assess the efficacy of a new treatment in randomized clinical trials (RCT). In cardiovascular trials, the often rare event of the relevant primary ...
  • Review of multivariate survival data 

    Gómez Melis, Guadalupe; Calle Rosingana, M. Luz; Serrat Piè, Carles; Espinal Berenguer, Anna (2004-09)
    External research report
    Open Access
    This paper reviews some of the main contributions in the area of multivariate survival data and proposes some possible extensions. In particular, we have concentrated our search and study on those papers that are relevant ...
  • Selecting the primary endpoint in a randomized clinical trial: the ARE method 

    Plana-Ripoll, Oleguer; Gómez Melis, Guadalupe (2016)
    Article
    Open Access
    The decision on the primary endpoint in a randomized clinical trial is of paramount importance and the combination of several endpoints might be a reasonable choice. Gómez and Lagakos (2013) have developed a method that ...
  • Selection of composite binary endpoints in clinical trials 

    Bofill Roig, Marta; Gómez Melis, Guadalupe (2017-10-12)
    Article
    Open Access
    The choice of a primary endpoint is an important issue when designing a clinical trial. It is common to use composite endpoints as a primary endpoint because it increases the number of observed events, captures more ...
  • Selection of the primary end point in an observational cohort study 

    Gómez Melis, Guadalupe; Plana Ripoll, Oleguer; Dafni, Urania (2016-04-12)
    Article
    Open Access
    Any study exploring specific research questions requires to test well-defined hypotheses that efficiently translate these questions into measurable quantities. To attribute differences in outcomes between two or more groups ...
  • Semi-competing risks methods accounting for interval-censoring 

    Porta Bleda, Núria; Calle Rosingana, M. Luz; Gómez Melis, Guadalupe (2009)
    Conference lecture
    Open Access
  • Sensory cut-off point obtained from survival analysis statistics 

    Garitta, Lorena; Langohr, Klaus; Gómez Melis, Guadalupe; Hough, Guillermo; Beeren, Cindy (2015-07)
    Article
    Open Access
    In the present work we applied interval-censored survival analysis techniques to estimate sensory cut-off points based on consumer’s decision to accept or reject food products taking into account the inherent variability ...
  • Simultaneous marginal survival estimators when doubly censored data is present 

    Julià, Olga; Gómez Melis, Guadalupe (2010-10)
    Article
    Restricted access - publisher's policy
    A doubly censoring scheme occurs when the lifetimes T being measured, from a well-known time origin, are exactly observed within a window [L,R] of observational time and are otherwise censored either from above (right-censored ...
  • Some theoretical thoughts when using a composite endpoint to prove the efficacy of a treatment 

    Gómez Melis, Guadalupe (2011)
    Conference report
    Open Access
    This paper discusses, following Gómez and Lagakos (2011) methodology, to what extent is there a gain in efficiency from adding a component event to a relevant endpoint when the treatment effect on this component is not as ...
  • Statistical considerations when using a composite endpoint for comparing treatment groups 

    Gómez Melis, Guadalupe; Lagakos, Stephen W. (2012-08)
    Article
    Restricted access - publisher's policy
    When comparing two treatment groups in a time-to-event analysis, it is common to use a composite event consisting of two or more distinct outcomes. The goal of this paper is to develop a statistical methodology to derive ...
  • Survival analysis model to estimate sensory shelf life with temperature and illumination as accelerating factors 

    Garitta, Lorena; Langohr, Klaus; Elizagoyen, Eliana; Gugole Ottaviano, Fernanda; Gómez Melis, Guadalupe; Hough, Guillermo (2018-09-01)
    Article
    Restricted access - publisher's policy
    The main objective of this study was to introduce a survival model to contemplate two simultaneous accelerating factors affecting a food product’s shelf life: temperature and illumination. A second objective was to consider ...
  • The asymptotic relative efficiency and the ratio of sample sizes when testing two different null hypotheses 

    Gómez Melis, Guadalupe; Gómez Mateu, Moisés (Institut d'Estadística de Catalunya, 2014-06)
    Article
    Open Access
    Composite endpoints, consisting of the union of two or more outcomes, are often used as the primary endpoint in time-to-event randomized clinical trials. Previously, Gómez and Lagakos provided a method to guide the decision ...
  • The GRASS Group (Grup de Recerca en Anàlisis eStadística de la Supervivència) 

    Gómez Melis, Guadalupe (Institut d'estadística de Catalunya, 2002)
    Article
    Open Access
    Ressenya sobre la recerca actual en estadística a Catalunya: resultats del grup d'investigació català "The GRASS Group (Grup de Recerca en Anàlisis eStadística de la Supervivència)"
  • The HLA-C*04:01/KIR2DS4 gene combination and human leukocyte antigen alleles with high population frequency drive rate of HIV disease progression 

    Olvera, Alex; Pérez Álvarez, Susana; Ibarrondo, Javier; Ganoza, Carmela; Lama, Javier R.; Lucchetti, Aldo; Cate, Steven; H. Hildebrand, William; Bernard, Nicole; Gómez Melis, Guadalupe; Sánchez, Jorge; Brander, Christian (2015-03-13)
    Article
    Open Access
    Objective: The objective of this study is to identify human leukocyte antigen (HLA) class I and killer-cell immunoglobulin-like receptor (KIR) genotypes associated with different risks for HIV acquisition and HIV disease ...
  • The role of survival functions in competing risks 

    Porta Bleda, Núria; Gómez Melis, Guadalupe; Calle Rosingana, M. Luz (2008-05-28)
    External research report
    Open Access
    Competing risks data usually arises in studies in which the failure of an individual may be classified into one of k (k > 1) mutually exclusive causes of failure. When competing risks are present, there are two main ...