This is based on the analysis of several substances from the vitreous humour of the eye of cadavers, according to an article published in the journal entitled Statistics in Medicine. Using this system, scientists have developed a piece of software that makes it possible to establish precisely the post mortem interval (PMI), information that will make the work of the police and the courts of justice easier.
To apply this technique the researchers analyse initially potassium, urea and hypoxantine (a DNA metabolite) concentrations present in the vitreous humour of the eye of the human cadaver, and introduce these figures into a computer programme. The software that has been invented by these Galician scientists uses this information and is capable of establishing the time at which death occurred.
“The equations we have developed now make it possible for us to estimate the PMI more precisely than before, and provide a useful and accessible tool to forensic pathologists that is easy to use” José Ignacio Munoz Barús, one of the authors of the study, explains to SINC, and who is also a specialist doctor from the Institute of Legal Medicine at the University of Santiago de Compostela.
The traditional techniques for estimating the PMI are based on the study of parameters such as the rectal temperature of the cadaver or one of the organs, such as the liver, in rigor mortis, or post mortem lividity examination. These methods are complemented by biochemical analyses of the body fluids. One of these is the vitreous humour, the gelatinous liquid that is found behind the crystalline lens of the eye.Muñoz Barús points out that the study, published recently in Statistics in
In this last case the researcher specifies that previous studies used a “linear regression mathematical model” which assumes that the concentrations of potassium, hypoxantine and urea increase in a linear way that is more or less constant throughout the post mortem interval. However, the new analyses suggest that those premises are not valid and that the statistical models known as generalized additive models (GAM) or the support vector machine (SVM) models are more flexible and much more useful, since they avoid the assumption of linearity”.
The precision and usefulness of these two models have been confirmed by chemical analysis in more than 200 vitreous humour samples. The doctor and the two mathematicians who have performed the study have verified that the SVM method offers more precise data, although the GAM method is more easy to assimilate to the linear model and understand graphically and numerically, “ for which reason both complement each other”.
The three scientists have incorporated all this information into the development of a free computer package (based on code “R”) which makes it possible to establish the PMI using four predictive variables: concentrations of potassium, hypoxantine and urea, and cause of death. In addition, the software makes it possible to show the results graphically. “In this way the estimation of the time of death and expert examination are made easier when attending the courts of justice”, Munoz Barús points out to SINC
“The precise determination of the exact time of death has been the subject of various studies going back to the 19th century, since this information is of paramount importance in the field of legal medicine, owing to its repercussions on crime and civil society. This new method offers an important contribution to this field”, the researcher concludes.
SINC Team | alfa
Why do animals fight members of other species?
24.04.2015 | University of California - Los Angeles
Is a small artificially composed virus fragment the key to a Chikungunya vaccine?
24.04.2015 | Paul-Ehrlich-Institut - Bundesinstitut für Impfstoffe und biomedizinische Arzneimittel
KAIST researchers published an article on the development of a novel technique to precisely track the 3-D positions of optically-trapped particles having complicated geometry in high speed in the April 2015 issue of Optica.
Daejeon, Republic of Korea, April 23, 2015--Optical tweezers have been used as an invaluable tool for exerting micro-scale force on microscopic particles and...
A very small and rare species of shark is swimming its way through scientific literature. But don't worry, the chances of this inches-long vertebrate biting...
Ever since computers have been small enough to be fixtures on desks and laps, their central processing has functioned something like an atomic Etch A Sketch, with electromagnetic fields pushing data bits into place to encode data.
Unfortunately, the same drawbacks and perils of the mechanical sketch board have been just as pervasive in computing: making a change often requires starting...
How is lightning initiated in thunderclouds? This is difficult to answer - how do you measure electric fields inside large, dangerously charged clouds? It was discovered, more or less by coincidence, that cosmic rays provide suitable probes to measure electric fields within thunderclouds. This surprising finding is published in Physical Review Letters on April 24th. The measurements were performed with the LOFAR radio telescope located in the Netherlands.
How is lightning initiated in thunderclouds? This is difficult to answer - how do you measure electric fields inside large, dangerously charged clouds? It was...
Max Planck researcher Buhalqem Mamtimin determines how much nitrogen oxide is released into the atmosphere from agriculturally used oases.
In order to make statements about current and future air pollution, scientists use models which simulate the Earth’s atmosphere. A lot of information such as...
23.04.2015 | Event News
23.04.2015 | Event News
13.04.2015 | Event News
24.04.2015 | Materials Sciences
24.04.2015 | Materials Sciences
24.04.2015 | Health and Medicine