Evaluation of Raman spectroscopy for the analysis of colored fibers: a collaborative study

A collaborative study on Raman spectroscopy was carried out by members of the ENFSI (European Network of Forensic Science Institutes) European Fibres Group (EFG) on three dyed fibers: two red acrylics and one red wool. Raman instruments from six different manufacturers were tested as well as nine different laser wavelengths ranging from blue (lambda = 458 nm) to near infrared-NIR (lambda = 1064 nm). This represents the largest comparison study of Raman analytical parameters carried out on identical fiber samples. For the chosen fiber and dye samples, red lasers (lambda = 633 and 685 nm) gave the poorest spectral quality whereas blue (458 nm), green (514 nm) and near infrared lasers (785, 830 and 1064 nm) provided average results. Blue (488 nm) and green lasers (532 nm) globally gave the best quality spectra. Fluorescence problems were often encountered with some of the excitation wavelengths and therefore a flexible Raman instrument equipped with different lasers can be recommended to measure forensic fiber samples. The instrument should also be equipped with a Raman microscope in order to be able to focus on a single fiber. This study shows that Raman spectroscopy usually enables the identification of the main dye present in a colored fiber; however, minor dye components are much more difficult to detect. SERRS (Surface Enhanced Resonance Raman Scattering) techniques give an improvement of the dye's spectral intensity but no spectral improvement was observed for the two red acrylic and red wool fibers tested.     

Raman spectroscopy and microspectrophotometry of reactive dyes on cotton fibres: Analysis and detection limits

A collaborative study on Raman spectroscopy and microspectrophotometry (MSP) was carried out by members of the ENFSI (European Network of Forensic Science Institutes) European Fibres Group (EFG) on different dyed cotton fabrics. The detection limits of the two methods were tested on two cotton sets with a dye concentration ranging from 0.5 to 0.005% (w/w). This survey shows that it is possible to detect the presence of dye in fibres with concentrations below that detectable by the traditional methods of light microscopy and microspectrophotometry (MSP). The MSP detection limit for the dyes used in this study was found to be a concentration of 0.5% (w/w). At this concentration, the fibres appear colourless with light microscopy. Raman spectroscopy clearly shows a higher potential to detect concentrations of dyes as low as 0.05% for the yellow dye RY145 and 0.005% for the blue dye RB221. This detection limit was found to depend both on the chemical composition of the dye itself and on the analytical conditions, particularly the laser wavelength. Furthermore, analysis of binary mixtures of dyes showed that while the minor dye was detected at 1.5% (w/w) (30% of the total dye concentration) using microspectrophotometry, it was detected at a level as low as 0.05% (w/w) (10% of the total dye concentration) using Raman spectroscopy. This work also highlights the importance of a flexible Raman instrument equipped with several lasers at different wavelengths for the analysis of dyed fibres. The operator and the set up of the analytical conditions are also of prime importance in order to obtain high quality spectra. Changing the laser wavelength is important to detect different dyes in a mixture.     

Ethnic Identity in Diverse Schools: Preadolescents’ Private Regard and Introjection in relation to Classroom Norms and Composition

Journal of Youth and Adolescence - Ethnic identity plays a key role in the normative development of children and adolescents, and efforts to provide a positive and safe environment for ethnic...     

Lis Pendens,Choice of Court Agreements and Abuse of Law Under Brussels Ibis

The Brussels Ibis Regulation aims to ‘improve the efficiency of choice of court agreements’ following widespread criticism of the Gasser judgment of the European Court of Justice. To this end, the Regulation introduces a priority mechanism in Article 31(2) in favour of the court designated in exclusive choice of court agreements. This article analyses, first, the problem, which the new priority mechanism in the Brussels Ibis Regulation intends to resolve. Second, it describes how the reforms in the Brussels Ibis Regulation address the practical issues raised by Gasser. In this regard, the relevance of the abuse of law doctrine in EU law will be discussed. Finally, the article considers the practical application of the new priority mechanism and in particular the standard of review the non-chosen court should adopt in applying Article 31(2) Brussels Ibis Regulation.

     

Psychopathy, traumatic exposure, and lifetime posttraumatic stress

This study examined two theoretical models on the interaction between psychopathy, traumatic exposure, and lifetime posttraumatic stress in a sample of 81 male detainees. In Model 1, the interpersonal and affective features of psychopathy were assumed to protect against posttraumatic stress. In Model 2, the lifestyle and antisocial traits of psychopathy were assumed to lead to a lifestyle that increases the risk of traumatic exposure and subsequent posttraumatic stress. The authors found significant negative bivariate associations between Psychopathy Checklist-Revised (PCL-R) total, Interpersonal and Affective facet scores, and posttraumatic stress. Model 1 was confirmed, as they found the interaction between the Affective facet and traumatic exposure had a significant negative effect on posttraumatic stress. Model 2 was rejected. The authors' findings confirm that the interpersonal and affective features of psychopathy are associated with an emotional deficit and that the affective features of psychopathy are crucial for understanding the relationship between psychopathy and anxiety.     

Classroom Predictors of National Belonging: The Role of Interethnic Contact and Teachers’ and Classmates’ Diversity Norms

Journal of Youth and Adolescence - Schools can be important for the development of national belonging in students with immigrant backgrounds. Following Contact Theory and prior research on...     

Psychopathy and predatory violence in homicide,violent, and sexual offences: Factor and facet relations

Purpose. Evidence has been found pointing to a relationship between psychopathy and predatory violence. The present study investigated the violence mode and its relationship with psychopathy on factor as well as on facet levels. It was hypothesized that predatory violence would be related to the affective and/or interpersonal facets of psychopathy. A subsidiary hypothesis was that sexual offences could also be differentiated by means of violence mode. Methods. Participants were 82 male inmates convicted of a violent crime, a sexual crime, or a homicide. Psychopathy was assessed with the Hare PCL‐R2 and the violence mode was assessed by means of Cornell's Aggressive Incident Coding Sheet, based on interviews with the offenders and a review of the official record. Results. On the psychopathy subcomponent level, only the interpersonal facet was positively related with predatory violence. This association makes sense considering that psychopaths' interactions with others are defined by gradients of power and control and narcissistic gratification, rather than by attachment patterns. By contrast, the antisocial facet was associated negatively with predatory violence. Our subsidiary hypothesis concerning the possibility of differentiating sexual violence on the basis of the two violence modes was not confirmed. Conclusions. The present results add to the growing evidence that predatory violence is related to the personality traits of psychopathy rather than to its life‐style and antisocial characteristics. Therefore, a risk analysis of future predatory violent behaviour might benefit from the inclusion of the assessment of the personality facets of psychopathy instead of focusing solely on the antisocial behaviour.