3 research outputs found
Sex determination from the femur in Portuguese populations with classical and machine-learning classifiers
The assessment of sex is of paramount importance in the establishment of the biological profile of a skeletal individual. Femoral relevance for sex estimation is indisputable, particularly when other exceedingly dimorphic skeletal regions are missing. As such, this study intended to generate population-specific osteometric models for the estimation of sex with the femur and to compare the accuracy of the models obtained through classical and machine-learning classifiers. A set of 15 standard femoral measurements was acquired in a training sample (100 females; 100 males) from the Coimbra Identified Skeletal Collection (University of Coimbra, Portugal) and models for sex classification were produced with logistic regression (LR), linear discriminant analysis (LDA), support vector machines (SVM), and reduce error pruning trees (REPTree). Under cross-validation, univariable sectioning points generated with REPTree correctly estimated sex in 60.0e87.5% of cases (systematic error ranging from 0.0 to 37.0%), while multivariable models correctly classified sex in 84.0-92.5% of cases (bias from 0.0 to 7.0%). All models were assessed in a holdout sample (24 females; 34 males) from the 21st Century Identified Skeletal Collection (University of Coimbra, Portugal), with an allocation accuracy ranging from 56.9 to 86.2% (bias from 4.4 to 67.0%) in the univariable models, and from 84.5 to 89.7% (bias from 3.7 to 23.3%) in the multivariable models. This study makes available a detailed description of sexual dimorphism in femoral linear dimensions in two Portuguese identified skeletal samples, emphasizing the relevance of the femur for the estimation of sex in skeletal remains in diverse conditions of completeness and preservation. (C) 2017 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved
New data about the 21st Century Identified Skeletal Collection (University of Coimbra, Portugal)
Cortical bone loss in a sample of human skeletons from the Muge Shell middens
The Muge shell middens of Cabeco da Arruda, Cabeco da Amoreira and Moita do Sebastiao (central Portugal) have been key sites of archaeological research for 150 years, possibly working as residential sites occupied by semi-sedentary communities during the final Mesolithic. The purposes of this article include the biocultural assessment of metacarpal cortical bone fragility and its associations with age at death, sex and osteoporotic fractures in the Portuguese Mesolithic, as well as a diachronic comparison of cortical bone health in Mesolithic (N = 34) and modern reference (N = 219) samples. Cortical bone at the Muge shell middens displays age and sex-specific trajectories of periosteal apposition and endosteal bone loss, most likely associated with hormonal and behavioural/cultural influences. Metacarpal endocortical bone loss seems to increase with age at death in females, with a simultaneous expansion of the diaphysis. The overall pattern of cortical bone health is similar to the pattern observed in a reference skeletal collection, but elderly women from Muge seem to lose less cortical bone than late twentieth century counterparts from Coimbra. Two older males exhibited vertebral compression fractures, but only one is possibly related with bone fragility.Fundacao para a Ciencia e TecnologiaPortuguese Foundation for Science and Technology [SFRH/BPD/74015/2010