Next Generation Identification system: Latent print matching algorithm and casework practices.

The development of automated fingerprint identification systems (AFIS) revolutionized casework in the friction ridge community. Through the evolution of AFIS development, algorithms have become increasingly sensitive and specific. Internal validation studies conducted by the Federal Bureau of Investigation Laboratory Division's Latent Print Units (LPU) assessed the performance of the Next Generation Identification (NGI) system's latent print matching algorithm under the various encoding methods of the Multi-Biometric Identification System (MBIS) platform for the purpose of casework implementation. Based on the results of these studies, casework practices in the LPU have become more streamlined and efficient. The increase in accuracy of the latent print matching algorithm has reduced the number of candidates compared per search. For fingerprints, the results showed the best indicator for the correct mate being the number one candidate was the difference in score between the first and second candidate. When the score difference was 1200 or higher, the first candidate was mated in 99.3% of the trials. This understanding may allow for additional quality assurance measures to be implemented in casework.

Publication trends in forensic science research: Friction ridge discipline.

2019 commemorates the 10 year anniversary of the National Academy of Sciences report, "Strengthening Forensic Science in the United States: A Path Forward," and one valuable way to measure progress in forensic science is through published research. The purpose of this study is to examine where the friction ridge discipline stands with respect to published research. Two time periods were selected (2005-2009 and 2010-2014) and two different methods were used to describe research growth and publication trends in this discipline. A bibliometric review was conducted using an online literature-indexing tool, Web of Science™, as well as an empirical method involving subject matter experts. Both methods showed an increased number of friction ridge articles published in scientific journals over time.

Potential effects of ionizing radiation on the evidentiary value of DNA, latent fingerprints, hair, and fibers: A comprehensive review and new results.

An extensive literature review and new post-irradiation experimental results are presented of genotyping blood stains and hair, and physical examinations of latent fingerprints, hairs, and fibers. Results indicate that successful development of nuclear short tandem repeat (STR) and mitochondrial DNA sequence profiles from human blood and hair evidence is possible-up to a point-following exposure to gamma, neutron, beta, and alpha radiation at several levels that would most likely be present at this type of crime scene (i.e., a "dirty bomb," etc.). Commencing at gamma radiation levels between 90 and 900kGy, DNA analysis using conventional DNA techniques was unsuccessful. In general, irradiation negatively affected the quality of latent fingerprints. All four radiation types degraded most fingerprint samples at all doses; nevertheless, many fingerprints remained of value for potential use in comparison. Although variable from one hair to another, microscopic changes observed for all types and levels of irradiation could potentially result in false exclusions. Negligible microscopic changes were observed in papers and fibers (used as substrates for fingerprints and bloodstains) up to 90kGy gamma, but fluorescence of fibers began to change above that dose. Paper and fibers, as well as plastic evidence enclosures, became extremely brittle leading to breakage after a gamma dose of 900kGy.

High mercury concentrations reflect trophic ecology of three deep-water chondrichthyans.

The relative contributions of proximity to mercury sources and trophic ecology to realized axial muscle mercury concentrations were explored for three deep-water chondrichthyans (Etmopterus princeps, Centroscymnus coelolepis, and Hydrolagus affinis), two species of which are harvested for human consumption. Samples were taken at three North Atlantic Ocean locations: the Azores, the Charlie Gibbs Fracture Zone, and the Bear Seamount. Despite the long distances between anthropogenic sources and the sampling locations, all species from all locations had muscle mercury concentrations exceeding the United States human health screening value of 0.3 mg/kg wet weight. Proximity to anthropogenic sources was not an obvious determinant of these elevated concentrations. Generally, mercury concentrations appeared to increase with increased dependence on benthic versus pelagic food sources (as indicated by interspecies differences in δ(13)C), and with higher position in the trophic web (as indicated by differences in δ(15)N).

Modeling mercury biomagnification (South River, Virginia, USA) to inform river management decision making.

Mercury trophic transfer in the South River (VA, USA) was modeled to guide river remediation decision making. Sixteen different biota types were collected at six sites within 23 river miles. Mercury biomagnification was modeled using a general biomagnification model based on delta(15)N and distance from the historic mercury release. Methylmercury trophic transfer was clearer than that for total Hg and, therefore, was used to build the predictive model (r(2) (prediction) = 0.76). The methylmercury biomagnification factors were similar among sites, but model intercept did increase with distance down river. Minimum Akaike's Information Criterion Estimation (MAICE) justified the incorporation of distance in the model. A model with a very similar biomagnification factor to the South River (95% confidence intervals [CI] = 0.38-0.52) was produced for a second contaminated Virginia river, the North Fork Holston River (95% CI = 0.41-0.55). Percent of total Hg that was methylmercury increased monotonically with trophic position. Trophic models based on delta(15)N were adequate for predicting changes in mercury concentrations in edible fish under different remediation scenarios.