The Experts below are selected from a list of 276 Experts worldwide ranked by ideXlab platform
Barbara Daniel - One of the best experts on this subject based on the ideXlab platform.
-
Wet powder suspensions as an additional technique for the enhancement of bloodied marks
Forensic Science International, 2011Co-Authors: Catherine Au, Hayley Jackson-smith, Ignacio Quinones, Benjamin Jones, Barbara DanielAbstract:The enhancement of marks in blood on dark surfaces poses significant challenges to the Forensic Scientist. Current methods of enhancement include the sequential use of acid dyes (acid yellow, acid violet and acid black). Acid yellow is used to greatest effect on lighter deposits of blood on a non-porous background, and is visualised using a light source which causes it to fluoresce [1]. However, further enhancement with acid violet and acid black produces a dark product which may fail to improve the contrast of the mark against a dark background. The use of wet powder suspensions (WPSs) has been proposed as a complementary procedure for use in fingermark enhancement, beyond its typical use in the enhancement of marks on adhesive surfaces. In this investigation, the use of WPS was tested in conjunction with conventional acid dye treatments on marks in blood deposited on a selection of substrates. The results demonstrated that white WPS alone or together with acid dyes results in an overall enhancement of mark quality (p < 0.005) on marks deposited on smooth non-porous surfaces. The technique was shown to not interfere with subsequent presumptive tests on blood. However WPS treatments were shown to reduce the amount of DNA recoverable from the marks, resulting on an average decrease of 91% compared to untreated controls. The decline in DNA yields was shown to result in a decrease in the quality of the DNA profiles obtained. The enhancement properties of WPS were evaluated by electron microscopy. It was shown that the titanium dioxide particles in the WPS primarily interact with the non-bloodied part of the mark, thus producing a contrasting effect with the background and acid dyes.
-
Wet powder suspensions as an additional technique for the enhancement of bloodied marks.
Forensic science international, 2010Co-Authors: Catherine Au, Hayley Jackson-smith, Ignacio Quinones, B J Jones, Barbara DanielAbstract:The enhancement of marks in blood on dark surfaces poses significant challenges to the Forensic Scientist. Current methods of enhancement include the sequential use of acid dyes (acid yellow, acid violet and acid black). Acid yellow is used to greatest effect on lighter deposits of blood on a non-porous background, and is visualised using a light source which causes it to fluoresce [1]. However, further enhancement with acid violet and acid black produces a dark product which may fail to improve the contrast of the mark against a dark background. The use of wet powder suspensions (WPSs) has been proposed as a complementary procedure for use in fingermark enhancement, beyond its typical use in the enhancement of marks on adhesive surfaces. In this investigation, the use of WPS was tested in conjunction with conventional acid dye treatments on marks in blood deposited on a selection of substrates. The results demonstrated that white WPS alone or together with acid dyes results in an overall enhancement of mark quality (p
Niamh Nicdaeid - One of the best experts on this subject based on the ideXlab platform.
-
jurors perceptions of Forensic science expert witnesses experience qualifications testimony style and credibility
Forensic Science International, 2018Co-Authors: Mccarthy A Wilcox, Niamh NicdaeidAbstract:Abstract The judicial system calls upon expert witnesses to testify in court when complex or specialized knowledge, beyond that of the lay person, is needed to interpret the evidence. Previous research has indicated that particular traits of the expert witness can affect their credibility in the eyes of the jury, however most of this research has been undertaken using mock jurors. In contrast, this study investigated the perceptions of real jurors. In particular, the research focused on the juror’s perception of the Forensic Scientists’ expertise and credibility during testimony in homicide cases. Data was gathered from jurors after nine homicide trials using both questionnaire (n = 29) and direct one to one interviews (n = 22). The jurors defined what they thought an expert witness was and what attributes were important in a Forensic Scientist. Jurors suggested that the expert witness’s education and years of experience were more important than certification or laboratory accreditation. The jurors’ perceptions of the credibility of the expert was based upon the academic qualifications of the expert, the confidence they portrayed in answering the questions ask of them, their demeanor and their status of being government employee. The use of narrative language and demonstrative aids by the Forensic science expert witness to explain the evidence was explored. Jurors described a deeper understanding as a result of narrative testimony and this was reported to be a key factor in the juror’s acceptance that the witness was credible.
Evan W Durnal - One of the best experts on this subject based on the ideXlab platform.
-
crime scene investigation as seen on tv
Forensic Science International, 2010Co-Authors: Evan W DurnalAbstract:Abstract A mysterious green ooze is injected into a brightly illuminated and humming machine; 10 s later, a printout containing a complete biography of the substance is at the fingertips of an attractive young investigator who exclaims “we found it!” We have all seen this event occur countless times on any and all of the three CSI dramas, Cold Cases , Crossing Jordans , and many more. With this new style of “infotainment” (Surette, 2007 [13] ), comes an increasingly blurred line between the hard facts of reality and the soft, quick solutions of entertainment. With these advances in technology, how can crime rates be anything but plummeting as would-be criminals cringe at the idea of leaving the smallest speck of themselves at a crime scene? Surely there are very few serious crimes that go unpunished in today's world of high-tech, fast-paced gadgetry. Science and technology have come a great distance since Sir Arthur Conan Doyle first described the first famous Forensic Scientist (Sherlock Holmes), but still have light-years to go.
Pierre Margot - One of the best experts on this subject based on the ideXlab platform.
-
identification of gunshot residue a critical review
Forensic Science International, 2001Co-Authors: Francesco Saverio Romolo, Pierre MargotAbstract:A review of the scientific papers published on inorganic gunshot residue (GSR) analysis permits to study how the particle analysis has shown its capability in detection and identification of gunshot residue. The scanning electron microscope can be the most powerful tool for Forensic Scientists to determine the proximity to a discharging firearm and/or the contact with a surface exposed to GSR. Particle analysis can identify individual gunshot residue particles through both morphological and elemental characteristics. When particles are detected on the collected sample, the analytical results can be interpreted following rules of a formal general interpretative system, to determine whether they come from the explosion of a primer or from other possible sources. The particles on the sample are compared with an abstract idea of “unique” GSR particle produced by the sole source of the explosion of a primer. “Uniqueness” is not the only problem related to GSR detection and identification for a Forensic Scientist. With “not-unique” particles interpretation of results is extremely important. The evidential strength of “not-unique” particles can increase with a more fruitful interpretative framework based on Bayes rule. For the assessment of the value of a GSR in linking a suspect and a crime, it is important to compare two hypothesis: the first can be that of the evidence if the suspect has been shooting in a specific situation, the second that of the evidence if the suspect was not involved in this shooting. This case specific or case-by-case approach is closer to what the court is interested in. The authors consider that a “case-by-case” approach should be followed whenever possible. Research of models and data such as those developed in other trace evidence material (fibres, glass, etc.) using a Bayesian approach is suggested in the interpretation of GSR.
R Horvath - One of the best experts on this subject based on the ideXlab platform.
-
chemometric classification of gunshot residues based on energy dispersive x ray microanalysis and inductively coupled plasma analysis with mass spectrometric detection
Spectrochimica Acta Part B: Atomic Spectroscopy, 2007Co-Authors: Sylvia Steffen, Matthias Otto, Ludwig Niewoehner, Martin Barth, Bro Z Zekmucha, Jan Biegstraaten, R HorvathAbstract:Abstract A gunshot residue sample that was collected from an object or a suspected person is automatically searched for gunshot residue relevant particles. Particle data (such as size, morphology, position on the sample for manual relocation, etc.) as well as the corresponding X-ray spectra and images are stored. According to these data, particles are classified by the analysis-software into different groups: ‘gunshot residue characteristic’, ‘consistent with gunshot residue’ and environmental particles, respectively. Potential gunshot residue particles are manually checked and – if necessary – confirmed by the operating Forensic Scientist. As there are continuing developments on the ammunition market worldwide, it becomes more and more difficult to assign a detected particle to a particular ammunition brand. As well, the differentiation towards environmental particles similar to gunshot residue is getting more complex. To keep external conditions unchanged, gunshot residue particles were collected using a specially designed shooting device for the test shots revealing defined shooting distances between the weapon's muzzle and the target. The data obtained as X-ray spectra of a number of particles (3000 per ammunition brand) were reduced by Fast Fourier Transformation and subjected to a chemometric evaluation by means of regularized discriminant analysis. In addition to the scanning electron microscopy in combination with energy dispersive X-ray microanalysis results, isotope ratio measurements based on inductively coupled plasma analysis with mass-spectrometric detection were carried out to provide a supplementary feature for an even lower risk of misclassification.