1,720,997 research outputs found
Towards innovation in paper dating: a MicroNIR analytical platform and chemometrics
No full textUsing a miniaturized near infrared spectrometer associated to chemometrics we developed a rapid and non destructive procedure to characterise paper and investigate its aging with the aim of solving dating problems. Two sets of paper were considered in this study (books and sheets) in order to ensure the results are not dependent of the storage conditions. The MicroNIR has the ability to distinguish paper according to the chemical composition of the surface as a function of the period of manufacturing. The optimized analytical platform is fast and simple, avoiding sample pre-treatment procedures. As a consequence, the approach may be considered as the optimal technology to carry out analysis of ancient paper or other similar materials for diagnostic or forensic purposes as it is entirely portable and non-destructive
75 years of forensic profiling: A critical review
Full text linkThe interest in characterization of drugs abused started in 1948 with the aim of determining the origin of opium. After 75 years there is still a great interest in this approach, called geo-profiling, chemical or forensic profiling in the following decades. Recently chemical attribution signatures (CAS) were proposed by the authors who studied “synthesis precursors and byproducts, impurities, degradation products, and metabolites in various biological matrices” of fentanyl. Forensic profiling evolved during these decades: new analytical approaches were tested and it was applied to more and more products, which threaten the health and security of citizens worldwide. In substances of natural origins (e.g. opium, cannabis and cocaine), it is possible to exploit the great variability of both elements and organic chemical compounds and to study chemical compounds such as reagents and solvents, by-products, and cutting agents used in the production chain. Profiles can be used to classify products from different seizures into groups of similar samples (tactical intelligence) or to determine the origin of samples (strategic intelligence). Chromatographic approaches coupled to mass spectrometry are very common to determine organic profiles, while elemental profiles are obtained by nuclear activation analysis, inductively coupled plasma mass spectrometry or ion beam analysis. A very important role in the field is played by isotope ratio analysis. Approaches to obtain forensic profiles are available also for chemical warfare agents, explosives, illegal medicines, doping agents, supplements, food. Chemometrics can be particularly useful to establish the authenticity of products and for the interpretation of large amount of forensic data. The future of forensic profiling is a challenge for forensic sciences. Organized crime is involved in the manufacturing of a large number of illegal products and forensic profiling is a very powerful tool to support the health of citizens and the administration of justice worldwide
Forensic analysis of commercial inks by laser-induced breakdown spectroscopy (LIBS)
Full text linkLaser-induced breakdown spectroscopy (LIBS) was tested for all of the relevant issues in forensic examinations of commercial inks, including classification of pen inks on one paper type and on different paper types, determination of the deposition order of layered inks, and analysis of signatures and toners on one questioned document. The scope of this work was to determine the potential of a single LIBS setup that is compatible with portable instruments for different types of ink analysis, rather than building a very large database for inks and papers. We identified up to seven metals characteristic for the examined inks, which allowed to fully discriminate all eight black inks on one type of printing paper. When the inks were tested on ten different papers, the correct classification rates for some of them were reduced for reasons thoroughly studied and explained. The replicated tests on three crossing points, each one involving a pair of blue or black inks, were successful in five cases out of six. In the test simulating documents of forensic interest (questioned documents), LIBS was able to correctly identify the differences in three inks used for signatures on one of the three pages and the use of different printing inks on each page of the document
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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