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Biomedical subjects

C G Aitken

Publications and source records attributed to C G Aitken.

8 recordsLinked to original sources
PubMed1989

Evaluation of enzyme immunoassays in the diagnosis of camel (Camelus dromedarius) trypanosomiasis: a preliminary investigation.

Three enzyme immunoassays were used for the serodiagnosis of Trypanosoma evansi in camels in the Sudan in order to evaluate their ability to discriminate between infected and non-infected animals. Two assays were used for the detection of trypanosomal antibodies, one using specific anti-camel IgG conjugate and another using a non-specific Protein A conjugate. The third assay detected the presence of trypanosomal antigens using anti-T. evansi antibodies in a double antibody sandwich assay. Inspection of the frequency distribution of assay results suggested that the ELISA for circulating trypanosomal antibodies using specific antisera and the ELISA for circulating antigens can distinguish between non-infected camels and infected camels exhibiting patent infections or not. The ELISA using Protein A conjugate to bind non-specifically to camel immunoglobulin did not appear to discriminate between infected and non-infected animals.

Animals↗
PubMed1987

A contribution to the discussion of probabilities and human hair comparisons.

The paper by Gaudette and Keeping on "An Attempt at Determining Probabilities in Human Scalp Hair Comparison" in the Journal of Forensic Sciences (Vol. 19, No. 3, July 1974, pp. 599-606) has provoked considerable controversy. This paper highlights two of the sources of the controversy and shows how the probability, 1/4500, quoted by Gaudette and Keeping should be treated with caution. The necessity of the use of a likelihood ratio statistic is described. It is suggested that the hair examination form resulting from the responses to the questionnaire recently distributed by the authors and also the discussions at Quantico (Proceedings of the International Symposium on Forensic Hair Comparisons, 25-27 June 1985, Quantico VA) should be used to facilitate the collection of the data which will be necessary to enable a likelihood ratio statistic to be estimated effectively.

Forensic Medicine↗
PubMed1986

The value of microscopic features in the examination of human head hairs: statistical analysis of questionnaire returns.

There is an apparent diversity of opinion with respect to the probative value of hair in the United Kingdom and in North America. A questionnaire was devised and widely circulated in an attempt to discover the reasons behind this diversity and to seek the views of a broad range of hair examiners. This paper reports on the statistical analyses of the answers to the closed form questions. The majority of replies to most questions favored the number of categories given in the questionnaire. The general impression is that U.K. scientists tend to want fewer categories for classification of microscopic features than the North Americans. The largest divisions of opinion concerned pigment distribution and density and the medulla, where North American scientists want more categories for classification and the U.K. scientists fewer. The implications of these results in the choice and description of features to be examined in human hairs is considered in the second paper concerned with this questionnaire.

Forensic Medicine↗
PubMed1986

The value of microscopic features in the examination of human head hairs: analysis of comments contained in questionnaire returns.

Comments received in response to a questionnaire seeking opinion about hair examination have been considered. The questionnaire was in two parts: the first was concerned with the description of microscopic features and the second with the use of numerical features and data sheets in hair examinations. The same format is used to present a synopsis of the many individual comments and suggestions contained in questionnaire returns. It is argued that a hair examination form can contribute to more effective hair examinations although not replacing direct side-by-side comparisons. A hair examination form is presented with recommendations for its use.

Forensic Medicine↗
PubMedDate not supplied

Statistical modelling in specific case analysis.

In spite of the problems associated with the development of a statistical approach in specific case analysis, the potential of two statistical methods, logistic regression and Bayesian belief networks, has been investigated and found encouraging in the context of a database relating to child murders with a sexual connotation. Continual collaboration between statisticians and detectives would be needed in the collection of the data, the choice and construction of the models, and the interpretation of the results.

Adult↗
PubMedDate not supplied

Probabilistic reasoning in the law. Part 1: Assessment of probabilities and explanation of the value of DNA evidence.

Problems associated with the interpretation of DNA evidence are investigated with reference to measures of uncertainty associated with the presentation of such evidence in an adversarial context. The use of probabilistic arguments associated with expert scientific testimony and cases where DNA evidence has been presented in court are studied. A series of problems were developed for, and given to, forensic medicine students, forensic science students and practitioners (advocates and forensic scientists) in Scotland to investigate their understanding of uncertainty. In the first part, four different methods of presentation of the value of DNA evidence were given to the participants and their responses are described. In the second part, different explanations of the value of DNA evidence as given by experts in court were given to the participants and their responses are described. The authors suggest improvements for the presentation of scientific evidence and for the education of future lawyers and forensic scientists.

DNA↗
PubMedDate not supplied

Probabilistic reasoning in the law. Part 2: Assessment of probabilities and explanation of the value of trace evidence other than DNA.

Problems associated with the interpretation of scientific evidence (fibres and glass) in forensic science are investigated with reference to measures of uncertainty associated with the presentation of such evidence in an adversarial context. The investigation includes the use of probabilistic arguments associated with expert scientific testimony in the courts. Cases where scientific evidence has been presented in court are studied. A series of problems were developed for, and given to, forensic medicine students' forensic science students and practitioners (advocates and forensic scientists) in Scotland to investigate their understanding of uncertainty.

Bayes Theorem↗