Discipline: Chemistry and Chemical Sciences
Subcategory: Chemistry (not Biochemistry)
David S.H. Funes - University of Central Florida
Co-Author(s): Jillian Morgan; Candice Bridge, Ph.D., University of Central Florida, Orlando, FL
Forensic examination of hair has been scrutinized due to the misinterpretation of probabilistic statements used in testimony. This has also led to many misjudgments of the evidentiary value of hair. There is in fact a limited amount of information available on the discriminatory power of each feature and their variation. This decreases the value of hair examinations with statistical support. However, evaluating inter- and intra-person variability among individuals from different ancestries will aid determining the strength of hair analysis. This study will focus on measurements of common microscopic features and additional suggested measurements. A Keyence VHX 6000 digital microscope was used to image 25 fallen hairs from individuals of different ethnicity. Hairs were washed to remove any hair product and to attempt to remove any treatment (except dyes) that affect the structure of the hair. Images and measurements were taken at 3 distinct locations throughout the hair and additional images to attempt characterizing the root of the hair and to note the presence of a medulla. Measurements of color, average width, average cuticle width, pigmentation density, medulla width, scales/mm, arc diameter, arc angle, number of wave-curls-twist, and texture analysis were taken for all hairs. The data collected this far has been analyzed using basic statistics and analysis of variance (ANOVA). Currently, 25 hair strands from 15 individuals have been imaged. The measurements taken thus far for widths showed that measurements at the proximal end of the hair have the lowest intra-person variability (15.8%) and the variability increases moving towards the distal end. ANOVA was use for measurements of macroscopic features and showed that the variation within groups is higher than between groups for waves and curls. As for color and texture, more consistency of color and texture is noted at least 1.00 mm away from the proximal end, calculations and methods for quantifying color are currently on going. It is expected that some of the features may not be significantly different overall, however, the data accumulated can be used to understand the inter and intra- person variability of features. Once all data has been collected, correlation between features and ethnicity will be made and the features with the most discriminating power will be used in attempts to generate a statistical model for classification.
Funder Acknowledgement(s): Funding: This project was supported by the State of Florida.
Faculty Advisor: Candice Bridge, firstname.lastname@example.org
Role: I am the primary researcher of this project. My part encompasses collection, data acquisition, and data analysis.