Determination of lanthanides in fossil samples using laser induced breakdown spectroscopy

As being a fast, simple and relatively non-destructive analytical technique Laser-induced breakdown spectroscopy (LIBS) has a large variety of applications including the analysis of paleontological samples. In this work LIBS is employed for the quantitative determination of lanthanides (Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Sm, Tb, Tm and Yb) in vertebrate fossil samples comprising teeth, disarticulated complete or fragmented bones, eggshell fragments, and coprolites of dinosaurs, mammals and crocodiles. For emission line data, standard AnalaR grade salts of lanthanides were used. The major components: Iron, calcium, magnesium, silicon and aluminum in the samples were also determined. The analytical information may be helpful in studying the samples for their age, formation environment and other paleontological properties

Direct determination of Al and Pb in waste printed circuit boards (PCB) by laser-induced breakdown spectroscopy (LIBS): Evaluation of calibration strategies and economic - environmental questions

Matrix-matching calibration (MMC), two-point calibration transfer (TP CT), one-point and multi-line calibration (OP MLC), single-sample calibration (SSC) and calibration free (CF) were evaluated in order to overcome matrix effects in laser-induced breakdown spectroscopy (LIBS). These calibration strategies were evaluated for direct determination of Al and Pb in waste printed circuit boards (PCB) using direct solids analysis by LIBS. Each strategy has limitations and advantages of its implementation, for the correction of matrix effects, so that it allows elementary determination with adequate accuracy. The MMC and CF proved to be excellent calibration strategies for the determination of strategic (Al) and toxic (Pb) elements by LIBS, with good recoveries (ranging from 80–120%) and low relative standard deviation (RSD%) values. A detailed discussion of the advantages and limitations of each of these five calibration strategies evaluated for LIBS is presented in this study. Lead concentrations in waste PCB samples are 5–12 times higher than established by Directive 2011/65/EU, and the samples analyzed contain between 3 and 55 g kg-1 Al, being an interesting economic and recycling source for this metal

Digital competence of university teachers of social and legal sciences from a gender perspective

Higher Education institutions must respond to the major challenges posed by the technological transformations of recent years. For this, one of the key aspects is that the teachers working in them are trained to incorporate these technologies in teaching–learning processes, which requires them to be digitally competent. To analyse how gender relates to the level of competence of teachers, the types of ICT tools that they use, and their attitudes towards their implementation in teaching– learning processes, this quantitative research was carried out with the participation of 121 university teachers from the Autonomous Community of Aragon, all of them from the area of Social and Legal Sciences. The results show a differentiated profile between men and women in terms of their attitudes, beliefs, and self-perception regarding their management skills and effectiveness. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Invisibilidad de la escuela rural en la formación de maestros

Initial teacher training is essential for future job performance in any teaching position. However, rural schools remain frequently overlooked. To address this issue, this research explores content specifically relating to rural schools in initial teacher training. An exhaustive review was carried out of the curricula, verification reports, and teaching guides of teaching degrees in public and private universities in Spain. The results show that rural schools are lacking in the educational skills teachers must acquire in their university education, with few courses specifically dealing with this type of school. In particular, we conclude that rural school training is essential due to the specific nature of these schools and there is a need to include this in teacher training, as some universities are already doing. La formación inicial de los maestros es clave para su posterior desempeño laboral en cualquiera de sus destinos; sin embargo, la escuela rural sigue siendo la gran olvidada. Para atender esa realidad, en esta investigación se analizan los contenidos específicos sobre la escuela rural en la formación inicial. Se realizó una revisión exhaustiva de los planes de estudio, memorias de verificación y guías docentes de los grados de magisterio de universidades españolas, tanto públicas como privadas. Los resultados muestran que la escuela rural está ausente en las competencias educativas que debe adquirir un maestro en su formación universitaria, siendo escasas las asignaturas específicas sobre la temática. En las conclusiones destaca la formación en escuela rural como un elemento esencial por su especificidad y la necesidad de que se incorpore a la formación de maestros –como algunas universidades ya lo hacen

Assessment of the variability of atmospheric pollution in national parks of mainland Spain

Air quality in nine National Parks in mainland Spain was assessed analysing SO2, NOx, O3, PM10 and PM2.5 data from background stations. As emissions in and around parks are limited, the levels of primary pollutants are low. Concentrations of secondary pollutants are high especially in summer due to photochemical production. The geographical variability of pollutants responds to regional emission patterns and the dominant circulation regimes in different regions resulting in west-east gradients for O3 and PM. Seasonal variability of pollutants was also interpreted in virtue of transport scenarios, changes in photochemical activity and emissions variability. NOx and SO2, maximize in winter due to higher emissions while O3 and PM do it in summer due to photochemical production, lower precipitation and, in the case of PM, the occurrence of African dust outbreaks. The diurnal evolution was interpreted in virtue of variability in emissions and changes in the Planetary Boundar Layer height

Multielemental analysis of Antarctic soils using calibration free laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a quick technique that allows the analysis of all types of samples without destroying them and with much reduced sample treatment. One of its many applications is the study of geological samples such as soils. Because of the complexity of the matrix, it is very difficult to find or manufacture standards for these types of samples. Therefore, a good alternative is to make use of a methodology, called Calibration Free (CF), where instead of using standards, the physical parameters of the plasma created by the interaction of the laser with the sample are studied and related to the elements and species that compose it. This methodology is followed to perform a multielemental quantitative analysis of soil samples from Antarctica. Two studies were made, differing in the optimization of the instrumental parameters in order to obtain the best possible spectra in the chosen spectral lines. In both cases, the signal to noise ratio (SNR) was used to evaluate the quality of the spectra, but in the second study a full factorial design 23 with center and axial points was developed to get better results. The choice of spectral lines was based on a series of criteria, being stricter in the second study. The samples were mainly composed of the following oxides: SiO2, Al2O3, Fe2O3, CaO, MgO, Na2O, TiO and K2O. In the second study, it was also possible to determine the species present in lower concentrations: Mn, Cr, V, Sr, Zr, BA and Li. The results were compared with those provided by ICP-OES analysis, obtaining close values for most oxides, especially in the second study. For minority elements, the CF-LIBS and the ICP-OES results were within the same order of magnitude in all cases except the Cr case. These results show that CF-LIBS can be very useful in the characterization of complex samples from remote regions, such as Antarctic soils

EMT-Induced Stemness and Tumorigenicity Are Fueled by the EGFR/Ras Pathway

10.1371/journal.pone.0070427PLoS ONE88-POLN