Portable instruments based on NIR sensors and multivariate statistical methods for a semiautomatic quality control of textiles

Near-infrared (NIR) spectroscopy is a widely used technique for determining the composition of textile fibers. This paper analyzes the possibility of using low-cost portable NIR sensors based on InGaAs PIN photodiode array detectors to acquire the NIR spectra of textile samples. The NIR spectra are then processed by applying a sequential application of multivariate statistical methods (principal component analysis, canonical variate analysis, and the k-nearest neighbor classifier) to classify the textile samples based on their composition. This paper tries to solve a real problem faced by a knitwear manufacturer, which arose because different pieces of the same garment were made with “identical” acrylic yarns from two suppliers. The sweaters had a composition of 50% acrylic, 45% wool, and 5% viscose. The problem occurred after the garments were dyed, where different shades were observed due to the different origins of the acrylic yarns. This is a challenging real-world problem for two reasons. First, there is the need to differentiate between acrylic yarns of different origins, which experts say cannot be visually distinguished before garments are dyed. Second, measurements are made in the field using portable NIR sensors rather than in a controlled laboratory using sophisticated and expensive benchtop NIR spectrometers. The experimental results obtained with the portable sensors achieved a classification accuracy of 95%, slightly lower than the 100% obtained with the high-performance laboratory benchtop NIR spectrometer. The results presented in this paper show that portable NIR sensors combined with appropriate multivariate statistical classification methods can be effectively used for on-site textile quality control.This research was partially funded by Generalitat de Catalunya under grant numbers ACE033/21/000028, 2021 SGR 00392, and 2021 SGR 01501.Peer ReviewedPostprint (published version

Morphobathymetry and formation processes of sediment waves in the Gulf of Valencia continental slope (NW Mediterranean)

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Impacto entre iguales en los resultados educativos en Economía

INTRODUCCIÓ. Aquest article aprofundeix en l’estudi de les interaccions entre iguals a l’aula universitària. MÈTODE. Avaluem els efectes del treball en equip en el rendiment acadèmic individual en quatre assignatures que utilitzen l’aprenentatge basat en equips (ABE) dels graus d’Economia i d’Administració d’Empreses. RESULTATS. Trobem que les qualificacions individuals dels estudiants tenen una associació positiva i significativa amb la qualificació mitjana de la resta de membres de l’equip. La puntuació pròpia de l’estudiant augmenta aproximadament 0,65 punts per cada augment d’1 punt a la nota mitjana dels companys d’equip. Aquesta associació continua sent positiva i significativa fins i tot quan incloem variables sociodemogràfiques per controlar les característiques individuals. També contrastem l’heterogeneïtat dels efectes dels companys segons la capacitat de rendiment individual i d’equip. DISCUSSIÓ. Els resultats suggereixen que no hi ha heterogeneïtat en la capacitat individual, però trobem una diferència positiva o lleugerament negativa en la magnitud de l’efecte del treball entre iguals per als equips que es troben en el quartil superior/inferior, en contrast amb els equips que es troben al mig en la distribució.INTRODUCTION. This paper contributes to the study of peer interactions in the university classroom. METHOD. We evaluate the effects of teamwork on individual academic performance in four Team Based Learning (TBL) courses in the degrees of Economics and Business Administration. RESULTS. We found that the average grade of the rest of the team members has a significant and positive association with the grade of the individual student. The student’s personal test score increases about 0.65 points for every 1-point increase in the average score of their teammates. This association remains positive and significant even when we include socio-demographic variables to control for individual characteristics. We also tested the heterogeneity of peer effects in relation to the ability of individual and team performance. DISCUSSION. The results suggest there is no heterogeneity in individual ability; however, we found a positive or slightly negative difference in the magnitude of the peer effect for teams in the top/bottom quartile compared to teams in the middle of the distribution.Este artículo profundiza en el estudio de las interacciones entre iguales en el aula universitaria. MÉTODO. Evaluamos los efectos del trabajo en equipo en el rendimiento académico individual en cuatro asignaturas que emplean el Aprendizaje Basado en Equipos (ABE) de los grados de Economía y Administración de Empresas. RESULTADOS. Encontramos que la calificación promedio del resto de los miembros del equipo tiene una asociación positiva y significativa con las calificaciones individuales de los estudiantes. La puntuación de la prueba del estudiante aumenta aproximadamente 0,65 puntos por cada aumento de 1 punto en la nota promedio de sus compañeros de equipo. Esta asociación sigue siendo positiva y significativa, incluso cuando incluimos variables sociodemográficas para controlar las características individuales. También probamos la heterogeneidad de los efectos de los pares por nivel de desempeño individual y de equipo. DISCUSIÓN. Los resultados sugieren que no hay heterogeneidad en la capacidad individual, pero encontramos una diferencia positiva o ligeramente negativa en la magnitud del efecto de los pares para los equipos en el cuartil superior/inferior en relación con los equipos en el medio de la distribución

Characterization of the species Malassezia pachydermatis and re-evaluation of its lipid dependence using a synthetic agar medium

The genus Malassezia includes lipophilic yeasts, which are part of the skin microbiota of various mammals and birds. Unlike the rest of Malassezia species, M. pachydermatis is described as non-lipid-dependent, as it is able to grow on Sabouraud glucose agar (SGA) without lipid supplementation. In this study we have examined the phenotypic variability within M. pachydermatis and confirmed its lipid-dependent nature using a synthetic agar medium. We used a selection of representative non-lipid-dependent strains from different animal species and three atypical lipid-dependent strains of this species, which were not able to grow after multiple passages on SGA. More than 400 lipid-dependent Malassezia isolates from animals were studied in order to detect the three lipid-dependent strains of M. pachydermatis. The identity of the atypical strains was confirmed by DNA sequencing. On the other hand, we have modified the Tween diffusion test, which is widely used in the characterization of these yeasts, by using a synthetic agar-based medium instead of SGA. This modification has proved to be useful for differentiation of M. pachydermatis strains,providing reproducible results and a straightforward interpretation. The finding of these peculiar lipid-dependent strains exemplifies the large variability within the species M. pachydermatis, which involves rare atypical strains with particular growth requirements

Genomic diversity in ochratoxigenic and non ochratoxigenic strains of Aspergillus carbonarius

Ochratoxin A (OTA) is a mycotoxin with nephrotoxic effects on animals and humans. Aspergillus carbonarius is the main responsible for OTA contamination of grapes and derived products. We present the genome resequencing of four A. carbonarius strains, one OTA producer and three atypical and unique non-OTA producing strains. These strains were sequenced using Illumina technology and compared with a reference genome of this species. We performed some specific bioinformatics analyses in genes involved in OTA biosynthesis. Data obtained in this study revealed the high genomic diversity within A. carbonarius strains. Although some gaps of more than 1,000 bp were identified in non-ochratoxigenic strains, no large deletions in functional genes related with OTA production were found. Moreover, the expression of five genes of the putative OTA biosynthetic cluster was down regulated under OTA-inducing conditions in the non-ochratoxigenic strains. Knowledge of the regulatory mechanisms involved in OTA biosynthesis will provide a deeper understanding of these nonochratoxigenic strains