Carlos Rivas Sánchez

New chemometrics in laser-induced breakdown spectroscopy for recognizing explosive residues

Detection of explosives in traces is an important area for preventing terrorist attacks and for anticipating their disastrous consequences. Laser-induced breakdown spectroscopy (LIBS) has been demonstrated to be an effective analytical technique for the detection and characterization of energetic materials. However, the major obstacle in the identification of explosives is their elevated spectral similarity with those compounds that share an analogous elemental composition. Despite that a number of different chemometric methods have been developed in the past for the detection of explosives, this hurdle remains latent today. Our recent efforts have been focused on the use of an alternative chemometric approach for improving the sensitivity and selectivity of LIBS for residue explosives identification. Through the survey of the spectral responses from the analysis of a variety of organic residues (either explosive or potential confusant materials) located on the surface of a support, relationships between the optical emission behaviors of residues and their corresponding hazardous nature have been extracted. By using the original intensities of the most relevant emission signals (C : CN : C2 : H : N : O) properly projected onto 2D subspaces, different machine learning classifiers have been designed and trained. This approach has been demonstrated to be capable for the identification of organic explosive residues against several potential confusant materials when they are placed on the surface of an aluminum support. False positive and false negative rates better than 5% are achieved. These results evidence a great stride in solving this particular problem, enabling the LIBS technology as a practical tool in complex applications related to homeland security.

Advanced recognition of explosives in traces on polymer surfaces using LIBS and supervised learning classifiers

The large similarity existing in the spectral emissions collected from organic compounds by laser-induced breakdown spectroscopy (LIBS) is a limiting factor for the use of this technology in the real world. Specifically, among the most ambitious challenges of todays LIBS involves the recognition of an organic residue when neglected on the surface of an object of identical nature. Under these circumstances, the development of an efficient algorithm to disclose the minute differences within this highly complex spectral information is crucial for a realistic application of LIBS in countering explosive threats. An approach cemented on scatter plots of characteristic emission features has been developed to identify organic explosives when located on polymeric surfaces (teflon, nylon and polyethylene). By using selected spectral variables, the approach allows to design a concise classifier for alerting when one of four explosives (DNT, TNT, RDX and PETN) is present on the surface of the polymer. Ordinary products (butter, fuel oil, hand cream, olive oil and motor oil) cause no confusion in the decisions taken by the classifier. With rates of false negatives and false positives below 5%, results demonstrate that the classification algorithm enables to label residues according to their harmful nature in the most demanding scenario for a LIBS sensor.

Obesity, job satisfaction and disability at older ages in Europe

This study investigates the interaction between obesity and disability and its impact on the levels of job satisfaction reported by older workers (aged 50-64) in ten European countries (Denmark, Sweden, Austria, Belgium, France, Germany, The Netherlands, Switzerland, Italy and Spain). Using longitudinal data from the Survey of Health, Ageing and Retirement in Europe for the years 2004, 2007 and 2011, we estimate a job satisfaction equation which includes a set of explanatory variables measuring workers obesity and disability status (non-disabled, non-limited disabled, and limited disabled). The results show that, after controlling for other variables, obese workers are more likely to be satisfied with their jobs as compared to those workers with normal weight (0.066 points). In addition, being limited disabled or having poor health contribute to reducing (by 0.082 and 0.172 points, respectively) this positive effect of being obese on job satisfaction. However, we do not find any differential effect of obesity on job satisfaction by disability status, except for those underweight individuals who are not limited in their daily activities. Overall, these findings support the hypothesis of lower expectations about jobs for obese workers, especially if they also have poor health.

Melomics music medicine (M3) to lessen pain perception during pediatric prick test procedure.

report. In private schools, the prevalence of FA-free diets was higher than in public and subsidized schools. For this analysis, the prevalence of FA-free diets was assessed by a positive response on the basis of a specialist’s report case including all FA declared. We have found that the upward trend in the prevalence of FA-free diet as a special diet in Hortaleza District school canteens in the last year of the survey is similar to that observed in Alerg ologica 2005 study for children (3). The reasons for this increase may be due to higher awareness, better diagnostic tests, changes in dietary habits, etc., but have not been established. However, we consider that the survey improved this condition specialist’s medical reports as a consequence of this as a surveillance requirement, achieving a greater awareness of this condition. These results are in line with previous studies that show an increase in the prevalence of tree nut and peanut allergies, and in severe allergic reactions induced by foods (10). These results also indicate that the socioeconomic gradient is a factor that could influence a higher risk of developing this condition, as has been shown previously (3). This year, the application of Regulation 1169/2011 of the EU information on food labeling of packaged foods in relation to allergens will come into effect, and the responsibility of traders in the food industry will become a major concern. This could change Hazard Analysis Critical Control Point (HACCP) policies, as this is an individual pathology, where food security in relation to episodes caused each year is not considered ‘food-borne outbreak’. Traditionally HACCP programs have been designed to control food safety, preferentially oriented to microbiological hazards. This kind of survey could help to improve awareness on FA for all food safety stakeholder policies and, from the point of view of public health, for specialist sanitary inspectors in hygiene and food safety of all administrations, to extend information and adopt appropriate criteria when new cases of FA are presented. School canteens represent a good source of information regarding FA trends in children.