1,721,048 research outputs found
Investigation of fires by unconventional IID (improvised incendiary device) and combustion residues on different materials by SPME-GC-MS
No full textIncendiary events are phenomena that have a different evolution depending on the place in which they occur, the type of fuel, combustive and ignition, the type of material involved and the time that elapses between ignition and extinction. In the past few months numerous riots or attacks in different part of the world were carried out by using petrol bombs or incendiary devices. To establish the dynamics of the incendiary event it is necessary to analyze the debris but to make the results reliable it is necessary that the sampling is carried out by expert personnel to ensure the chain of custody of the evidence collected. Once sampled, the samples must be properly stored and sent to the competent laboratory for subsequent analyzes, which must be conducted in line with the reference standards. For the analysis of volatile substances, headspace extraction (HS) with the microextraction in solid phase (SPME) is used with subsequent analysis in gas chromatography coupled to the mass spectrometer (GC-MS). Given the variability of the operating conditions, the materials involved and the ignition methods, it can be said that there are no identical incendiary events, so through the multivariate analysis of the data it is possible to highlight correlations and differences between the various events. The creation of a model that allows the classification of a sample since the comparison with the typical compounds of a primer allows to facilitate the analyzes and to have reliable results. In this way, by reconstructing the dynamics of the event, it is possible to verify any criminal liability related to the presence or absence of flammable liquids or solids extraneous to the scene. In order to make the scientific result easily accessible to non-experts, the verbal scale of the likelihood ratio (LR) was introduced by the ENFSI in 2010.
During the work a simulation was performed by using a Molotov device made with a diesel-sulfuric acidic mix (3:1). A cloth was used as a stopper separating a bag of paper containing potassium chlorate. When the bottle breaks, the mixture comes into contact with the salt giving the formation of a colorless flame that starts the reaction. We have planned experiments with 16 fireboxes, with negative controls for a total of 120 samples.
After the creation of the chemometric model on the basis of the simulation results, data relating to a real case of a malicious nature were used in the model to verify whether or not the considered flammable materials had been used. The insertion of the data in the classification model returned an ambiguity of the results, in fact 2 out of the 15 collected samples were incorrectly assigned to the kerosene class while the other 13 samples were assigned to the class of IED. In this case the uncertainty in the evaluation is not attributable to a defect in the model but rather to the liquid used to make the illicit act. From the investigations carried out by the competent authorities, the suspect used gasoil, an oil derivative such as kerosene but belonging to a different class and present in the ratio 3:1 with sulfuric acid of studied IED
Identification by GC-MS Analysis of Organics in Manufactured Articles through a D-Optimal Design
Full text linkMany manufactured articles are made of composite materials often bonded by a phenolic resin. Through a D-optimal design, we optimized a method to characterize phenolic resins after the extraction process by GC-MS analysis. The study was conducted on three different phenolic resins and four manufactured articles with the same inorganic composition and different analyzed binders. Moreover, three cardanol resins that differ in their production systems were analyzed to see if there were differences between them. Through Soxhlet extraction with dichloromethane or acetone, it is possible to differentiate the raw materials through characteristic compounds and to identify them in the manufactured articles
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
METALLOCENE COMPOUNDS AND LABELED MOLECULES COMPRISING THE SAME FOR IN VIVO IMAGING
No full textThe present invention concerns compounds and methods of labeling peptides or other molecules withF orF or any other suitable radionuclide o use, for example, in PET or NMPv in vivo imaging. A targeting molecule such as a protein or a peptide is linked to a substituted metal locene complex which is reacted with theF orF shortly before performing the PET or NMR in vivo imaging on the patient. In certain embodiments, the labeled molecule may be used for targeting a cell, tissue, organ or pathogen to be imaged or detected. Exemplary targeting molecules include, but are not limited to, an antibody, antigen- binding antibody fragment, bispecific antibody, affibody, diabody, minibody, ScFvs, aptamer, avimer, targeting peptide, somatostatin, bombesin, octreotide, RGD peptide, folate, folate analog or any other molecule known to bind to a disease-associated target
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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