UNION STRUCTURE AND THE INCENTIVES FOR INNOVATION IN OLIGOPOLY

In this paper we consider the effect of union structure on the adoption of innovation in the context of Cournot duopoly. With a market size large enough we show that the incentive to innovate is higher under a decentralized union structure (with each firm facing its own independent union) than under an industry-wide union. However, for a small market size (or, equivalently, for sufficiently drastic potential innovation) the new technology is more likely to be adopted in the presence of a centralized union. This result goes against the conventional view that unionization harms the incentive to innovate.Oligopoly, Unions, Innovation.

Analysis of amino acid mixtures by voltammetric electronic tongues and artificial neural networks

A new voltammetric electronic tongue formed with graphite-epoxy composite electrodes which were modified with metal-oxide nanoparticles is presented for the quantification of tryptophan, tyrosine and cysteine aminoacid mixtures. The signals were obtained by cyclic voltammetry, and data was processed using two different chemometric techniques, artificial neural networks and partial least squares regression, for comparison purposes. Before performing artificial neural networks data was compressed by fast Fourier transform or discrete wavelet transform. The best results were attained using artificial neural networks with previous fast Fourier transform compression of the data with a normalized root-mean-square error of 0.032 (n=15) for the external test subset. The present method shows results comparable to other similar approaches, but with a much easier sampling process for the training set and new electrode modifiers to form the voltammetric sensors

Electronic tongue for nitro and peroxide explosive sensing

Altres ajuts: the support from the program ICREA Academia.This work reports the application of a voltammetric electronic tongue (ET) towards the simultaneous determination of both nitro-containing and peroxide-based explosive compounds, two families that represent the vast majority of compounds employed either in commercial mixtures or in improvised explosive devices. The multielectrode array was formed by graphite, gold and platinum electrodes, which exhibited marked mix-responses towards the compounds examined; namely, 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), pentaerythritol tetranitrate (PETN), 2,4,6-trinitrotoluene (TNT), N-methyl-N,2,4,6-tetranitroaniline (Tetryl) and triacetone triperoxide (TATP). Departure information was the set of voltammograms, which were first analyzed by means of principal component analysis (PCA) allowing the discrimination of the different individual compounds, while artificial neural networks (ANNs) were used for the resolution and individual quantification of some of their mixtures (total normalized root mean square error for the external test set of 0.108 and correlation of the obtained vs. expected concentrations comparison graphs r>0.929)

Artificial neural networks for the resolution of dopamine and serotonin complex mixtures using a graphene-modified carbon electrode

Marta Bonet-San-Emeterio thanks to AGAUR, Generalitat de Catalunya and to European Social Fund, European Union for FI fellowship. Manel del Valle thanks the support from program ICREA Academia.This work explores an electrode modified with electrochemically reduced graphene oxide (ERGO) for the voltammetric resolution of mixtures of neurotransmitters and its most common interferents. This enhanced sensitivity device coupled with advanced chemometric tools, such as artificial neural networks (ANNs), is able to resolve and quantify complex mixtures with overlapped signals. In this case, it has been applied to dopamine (DA), serotonin (5-hydroxytryptamine, 5-HT) and its main physiologic interferents, ascorbic acid (AA) and uric acid (UA), which play a relevant role in human body. The results obtained for individual analysis make evident a higher sensitivity of the developed sensor than the unmodified electrode. Furthermore, it has been attained an ANN response model with good correlation ability allowing the separation and quantification of each compound with comparison slope of predicted vs. expected concentrations with correlation better than 0.974. In short, the developed ERGO-modified sensor not only improved the signal but it also permitted resolving and quantifying each compound in complex mixtures when the proper chemometric treatment was used

Crown ether-modified electrodes for the simultaneous stripping voltammetric determination of Cd(II), Pb(II) and Cu(II)

This work describes the immobilization of 4-carboxybenzo-18-crown-6 (CB-18-crown-6) and 4-carboxybenzo-15-crown-5 (CB-15-crown-5) assisted by lysine on aryl diazonium salt monolayers anchored to the surface of graphite-epoxy composite electrodes (GEC), and their use for the simultaneous determination of Cd(II), Pb(II) and Cu(II) by differential pulse anodic stripping voltammetry (DPASV). These modified electrodes display a good repeatability and reproducibility with detection and quantification limits at levels of µg L(-1) (ppb), confirming their suitability for the determination of Cd(II), Pb(II) and Cu(II) ions in environmental samples. The overlapped nature of the multimetal stripping measurements was resolved by employing the two-sensor array CB-15-crown-5-GEC and CB-18-crown-6-GEC, since the metal complex selectivity exhibited by the considered ligands could add some discrimination power. For the processing of the voltammograms, Discrete Wavelet Transform and Causal Index were selected as preprocessing tools for data compression coupled with an artificial neural network for the modeling of the obtained responses, allowing the resolution of mixtures of these metals with good prediction of their concentrations (correlation with expected values for an external test subset better than 0.942)

Dummy molecularly imprinted polymers using dnp as a template molecule for explosive sensing and nitroaromatic compound discrimination

Altres ajuts: program ICREA Academia/Generalitat de Catalunya.This work reports a rapid, simple and low-cost voltammetric sensor based on a dummy molecularly imprinted polymer (MIP) that uses 2,4-dinitrophenol (DNP) as a template for the quantification of 2,4,6-trinitrotoluene (TNT) and DNP, and the identification of related substances. Once the polymer was synthesised by thermal precipitation polymerisation, it was integrated onto a graphite epoxy composite (GEC) electrode via sol-gel immobilisation. Scanning electron microscopy (SEM) was performed in order to characterise the polymer and the sensor surface. Responses towards DNP and TNT were evaluated, displaying a linear response range of 1.5 to 8.0 µmol L for DNP and 1.3 to 6.5 µmol L for TNT; the estimated limits of detection were 0.59 µmol L and 0.29 µmol L, for DNP and TNT, respectively. Chemometric tools, in particular principal component analysis (PCA), demonstrated the possibilities of the MIP-modified electrodes in nitroaromatic and potential interfering species discrimination with multiple potential applications in the environmental field

Predictive Variables of Adolescents' Intention to Be Physically Active after Graduation. Is Gender a Conditioning Factor?

The acquisition of physical activity habits during adolescence is fundamental to guarantee its adherence throughout life. However, these levels decrease during this stage, with women experimenting a more significant decrease. This paper aims to analyze if there are significant differences in the variables related to the intention to be physically active between men and women and if there is a moderating effect of gender on the variables that predict this intention. The sample is composed of 256 adolescents, aged between 16 and 19 years, 55.50% of whom are men, and 44.50% women. The results show that there are statistically significant differences (p < 0.05), with boys showing higher scores in the intention, athletic identity, and in the strength, condition, and attractiveness. About the predictive variables of the intention, the gender moderates the relationships between the physical attractiveness, condition and strength with the perceived behavioral control (pcfmale-pcfmale = 0.44; −0.48 p < 0.001; 0.27, p < 0.05, respectively), and between the subjective norm and the intention to be physically active (pcmale-female = 0.33, p < 0.01). These results highlight the importance of considering gender when designing specific policies for the promotion of physical-sports practice among adolescents to reduce the existing gender gap

Crown ether-modified electrodes for the simultaneous stripping voltammetric determination of Cd(II), Pb(II) and Cu(II)

This work describes the immobilization of 4-carboxybenzo-18-crown-6 (CB-18-crown-6) and 4-carboxybenzo-15-crown-5 (CB-15-crown-5) assisted by lysine on aryl diazonium salt monolayers anchored to the surface of graphite-epoxy composite electrodes (GEC), and their use for the simultaneous determination of Cd(II), Pb(II) and Cu(II) by differential pulse anodic stripping voltammetry (DPASV). These modified electrodes display a good repeatability and reproducibility with detection and quantification limits at levels of µg L−1 (ppb), confirming their suitability for the determination of Cd(II), Pb(II) and Cu(II) ions in environmental samples. The overlapped nature of the multimetal stripping measurements was resolved by employing the two-sensor array CB-15-crown-5-GEC and CB-18-crown-6-GEC, since the metal complex selectivity exhibited by the considered ligands could add some discrimination power. For the processing of the voltammograms, Discrete Wavelet Transform and Causal Index were selected as preprocessing tools for data compression coupled with an artificial neural network for the modeling of the obtained responses, allowing the resolution of mixtures of these metals with good prediction of their concentrations (correlation with expected values for an external test subset better than 0.942)