Variability and subjectivity in the grading process for evaluating the performance of latent fingermark detection techniques

When assessing latent fingermark development methods, forensic researchers commonly evaluate treated samples using a grading scale. However, the subjective nature of these evaluation methods leaves the results of such investigations open to criticism for potential grader bias. Assessment of fingermark development quality is ultimately dependent on an individual's background and experience. A pilot study was conducted as a preliminary stage of a large-scale international collaboration. A set of 80 fingermark samples was developed with 1,2-indanedione-zinc chloride. Grades for photographic images of the developed fingermarks were assigned independently by 11 fingermark researchers. Sixty-seven percent of the scores given to each individual sample were the same as the median grade, and 99% of the scores were within 1 grade. The researchers were also assessed on their consistency by including 20 duplicate images to be graded. Seventy-eight percent of the grades given were identical to their original scores. These results indicate that a small group of independent fingermark graders is sufficient to produce reliable and consistent data in projects requiring the assessment of fingermark quality

The visualisation of fingermarks on Pangolin scales using gelatine lifters

Recent media reports document the plight of the Pangolin and its current position as “the most trafficked mammal in the world”. They are described by some as scaly anteaters as all species are covered in hard keratinous tissue in the form of overlapping scales acting as a “flexible dermal armour”. It is estimated that between 2011 and 2013, 117,000–234,000 pangolins were slaughtered, but the seizures may only represent as little as 10% of the true volume of pangolins being illegally traded. In this paper, methods to visualise fingermarks on Pangolin scales using gelatine lifters is presented. The gelatine lifters provide an easy to use, inexpensive but effective method to help wildlife crime rangers across Africa and Asia to disrupt the trafficking. The gelatine lifting process visualised marks producing clear ridge detail on 52% of the Pangolin scales examined, with a further 30% showing the impression of a finger with limited ridge detail. The paper builds on an initial sociotechnical approach to establishing requirement, then it focuses on the methods and outcomes relating to lifting fingermarks off Pangolin scales using gelatine lifters, providing an evaluation of its use in practice

The visualisation on Pangolin scales using gelatine lifters

Recent media reports document the plight of the Pangolin and its current position as “the most trafficked mammal in the world”. They are described by some as scaly anteaters as all species are covered in hard keratinous tissue in the form of overlapping scales acting as a “flexible dermal armour”. It is estimated that between 2011 and 2013, 117,000 to 234,000 pangolins were slaughtered, but the seizures may only represent as little as 10% of the true volume of pangolins being illegally traded. In this paper, methods to visualise fingermarks on Pangolin scales using gelatine lifters is presented. The gelatine lifters provide an easy to use, inexpensive but effective method to help wildlife crime rangers across Africa and Asia to disrupt the trafficking. The gelatine lifting process visualised marks producing clear ridge detail on 52% of the Pangolin scales examined, with a further 30% showing the impression of a finger with limited ridge detail. The paper builds on an initial sociotechnical approach to establishing requirement, then it focuses on the methods and outcomes lifting fingermarks off Pangolin scales using gelatine lifters, providing an evaluation of the viability of using the lifters in practice

Non-invasive detection and chemical mapping of trace metal residues on the skin

Residual traces of the metals copper and lead on an individual's skin may be elucidated by reaction of rubeanic acid with a gelatine lift taken from the target area in question, yielding intensely coloured reaction products. This non-invasive technique has been shown to offer promise in chemically mapping the distribution of the minute metal residues across an individual's hand deposited through touching metal items, a technique with potential forensic significance

Home Office Fingerprint Source Book

The Fingerprint Source Book is primarily intended to provide the background and validation for the techniques currently (up to 2016) recommended by the Home Office Centre for Applied Science and Technology (CAST), and to publish, in some cases for the first time, data collected over 45 years of research. It will therefore often present information in an ‘CASTcentric’ way, emphasising research that was carried out at Sandridge or Horseferry House, possibly sometimes at the expense of research carried out elsewhere. It is not the intention of the authors to ignore the significant contributions made by other research groups and apologies are made in advance if this sometimes appears to be the case. The document is also aimed at providing the UK Forensic Science Regulator and the United Kingdom Accreditation Service (UKAS), which has carried out ISO 17025 accreditation in the UK, with the background evidence behind the advice given in the Fingermark Visualisation Manual

Scale-free memory model for multiagent reinforcement learning. Mean field approximation and rock-paper-scissors dynamics

A continuous time model for multiagent systems governed by reinforcement learning with scale-free memory is developed. The agents are assumed to act independently of one another in optimizing their choice of possible actions via trial-and-error search. To gain awareness about the action value the agents accumulate in their memory the rewards obtained from taking a specific action at each moment of time. The contribution of the rewards in the past to the agent current perception of action value is described by an integral operator with a power-law kernel. Finally a fractional differential equation governing the system dynamics is obtained. The agents are considered to interact with one another implicitly via the reward of one agent depending on the choice of the other agents. The pairwise interaction model is adopted to describe this effect. As a specific example of systems with non-transitive interactions, a two agent and three agent systems of the rock-paper-scissors type are analyzed in detail, including the stability analysis and numerical simulation. Scale-free memory is demonstrated to cause complex dynamics of the systems at hand. In particular, it is shown that there can be simultaneously two modes of the system instability undergoing subcritical and supercritical bifurcation, with the latter one exhibiting anomalous oscillations with the amplitude and period growing with time. Besides, the instability onset via this supercritical mode may be regarded as "altruism self-organization". For the three agent system the instability dynamics is found to be rather irregular and can be composed of alternate fragments of oscillations different in their properties.Comment: 17 pages, 7 figur

Understanding Human-Plasmodium falciparum Immune Interactions Uncovers the Immunological Role of Worms

BACKGROUND: Former studies have pointed to a monocyte-dependent effect of antibodies in protection against malaria and thereby to cytophilic antibodies IgG1 and IgG3, which trigger monocyte receptors. Field investigations have further documented that a switch from non-cytophilic to cytophilic classes of antimalarial antibodies was associated with protection. The hypothesis that the non-cytophilic isotype imbalance could be related to concomittant helminthic infections was supported by several interventions and case-control studies. METHODS AND FINDINGS: We investigated here the hypothesis that the delayed acquisition of immunity to malaria could be related to a worm-induced Th2 drive on antimalarial immune responses. IgG1 to IgG4 responses against 6 different parasite-derived antigens were analyzed in sera from 203 Senegalese children, half carrying intestinal worms, presenting 421 clinical malaria attacks over 51 months. Results show a significant correlation between the occurrence of malaria attacks, worm carriage (particularly that of hookworms) and a decrease in cytophilic IgG1 and IgG3 responses and an increase in non-cytophilic IgG4 response to the merozoite stage protein 3 (MSP3) vaccine candidate. CONCLUSION: The results confirm the association with protection of anti-MSP3 cytophilic responses, confirm in one additional setting that worms increase malaria morbidity and show a Th2 worm-driven pattern of anti-malarial immune responses. They document why large anthelminthic mass treatments may be worth being assessed as malaria control policies

Filarial Parasites Develop Faster and Reproduce Earlier in Response to Host Immune Effectors That Determine Filarial Life Expectancy

During larval development, filarial nematodes adjust their lifelong reproductive strategy to the presence of anti-parasitic immune cells that determine host resistance and experimental vaccine efficacy

Volatilised pyrene: A phase 1 study demonstrating a new method of visualising fingermarks with comparisons to iodine fuming

Pyrene is a fluorescent polycyclic aromatic hydrocarbon that can be volatilised under mild conditions. When fumed, pyrene is rapidly absorbed into the sebaceous residues of fingermarks, enabling their fluorescent visualisation upon excitation with ultraviolet radiation. This new means of fluorescent fingermark detection is more sensitive than the non-fluorescent iodine fuming approach for nonporous surfaces. This is demonstrated here in a phase 1 study using split-print comparisons on metal and glass surfaces. Pyrene-treated fingermarks also retain the volatile fluorophore for comparably long time periods relative to iodine fuming (in the order of hours). The phase 1 study comprised four donors, and 80 natural fingermarks that were grouped into two time periods; aged 24 h and 1 week. Iodine fuming was chosen as a reference to showcase the effectiveness of pyrene given it is the most closely-related chemical fuming method in routine use. This study demonstrates that pyrene fuming increases the quantity and quality of fingermark visualisations relative to iodine fuming, and is free of many of the latter method’s drawbacks. Preliminary results shown here also show the effectiveness of pyrene fuming on highly patterned surfaces, and its compatibility with the use of gelatine lifters. Pyrene fuming is thus easy to effect, low-cost, and shows great promise as a new means of visualising fingermarks on non-porous surfaces