L’incidence du salaire minimum sur le marché du travail des adolescents au Canada : une reconsidération des résultats empiriques

Un des résultats les moins controversés de la théorie économique est la prédiction que l’imposition d’un salaire minimum a des effets néfastes sur l’emploi. Des études empiriques réalisées dans les années soixante-dix et au début des années quatre-vingt ont confirmé la présence de ces effets, surtout chez les adolescents. Par ailleurs, depuis le milieu des années soixante-dix, le salaire minimum au Canada a très peu augmenté et a même baissé en termes réels, ce qui aurait dû affecter l’emploi favorablement. Le but de cette étude est de tenter de vérifier si le salaire minimum a toujours le même impact négatif sur le marché du travail des adolescents au Canada durant la période 1976-1988. À cette fin, nous estimons un modèle semblable à ceux des études antérieures. Les résultats sont différents de ceux de ces études : l’indice du salaire minimum n’est pas significatif dans les régressions estimées. Il semblerait donc que le salaire minimum ait un impact plus faible, ou du moins plus incertain, que par le passé. Quelques explications possibles aux changements observés sont suggérées. Certaines ont trait aux données utilisées et à la façon de mesurer les variables du modèle, alors que d’autres se rapportent aux relations théoriques entre ces variables.One of the least controversial issues in economic theory is the prediction that the imposition of a minimum wage has a negative impact on employment. Empirical studies performed during the seventies and the early eighties have confirmed the presence of that impact, especially among teenagers. Since the mid-seventies, however, minimum wages in Canada have changed very little and have even decreased in real terms. This should have had a favourable effect on employment. The purpose of this study is to see if the minimum wage still has the same negative effect on the labour market of teenagers in Canada during the period 1976-1988. To that effect, a model similar to those of the previous empirical studies is estimated. The results are different from those of the earlier studies: the minimum wage index is no longer significant in the estimated regressions. This suggests that the influence of the minimum wage on the labour market of teenagers is weaker than it used to be or, at least, that it is more uncertain. Possible explanations of the observed changes are discussed. Some are related to the data and to the way certain variables of the model are measured, while others pertain to the theoretical relationships among those variables

Electrochemical characterization of YSZ thick films deposited by dip-coating process

Yttria stabilized zirconia (YSZ, 8% Y2O3) thick films were coated on dense alumina substrates by a dip-coating process. The suspension was obtained by addition of a polymeric matrix in a stable suspension of commercial YSZ (Tosoh) powders dispersed in an azeotropic mixture MEK–EtOH. The suspension composition was improved by the addition of YSZ Tosoh particles encapsulated by zirconium alkoxide sol containing yttrium nitrate which are the precursors of the 8-YSZ oxide. This optimal formulation allowed preparing, via a dip-coating process, thick films which were, after thermal treatment, homogeneous, dense and crack-free. A specific method was performed to measure the electrical conductivity, i.e. to determine the ionic conductivity of the film: it uses the four-point probe technique combined with ac impedance spectroscopy. The good agreement between the classical two-electrode measurements performed on YSZ pellets and the four-electrode ones performed on YSZ films allows concluding that this method is relevant for characterizing the transport properties of thick films

Intermediate temperature SOFC single cell test using Nd1.95NiO4+δ as cathode

This work deals with SOFC single cell tests using neodymium nickelate Nd1.95NiO4+δ as cathode material. This MIEC oxide exhibits high values of both surface exchange coefficient (k) and oxygen diffusion coefficient (D*), as well as high electronic conductivity, which result in an enhanced electrochemical activity with respect to classical materials. The SOFC cells were fabricated from an anode-supported electrolyte half-cell provided by InDEC B.V. Corporation, with a 36mmdiameter. The Nd1.95NiO4+δ cathode was prepared as a two-stage electrode consisting of a thin interlayer of several hundred nanometers covered by a thicker layer of dozens microns. The Nd1.95NiO4+δ oxide powders were synthesized using different routes in order to reduce the final annealing temperature, and to subsequently obtain submicronic powders. I–V characteristics of the single cells were investigated under hydrogen–air conditions. The power densities versus current densities curves are reported and the results of impedance spectroscopy measurements performed under these operating conditions are discussed

Detection of streptococcus suis in bioaerosols of swine confinement buildings

Streptococcus suis is an important swine pathogen that can cause septicemia, meningitis, and pneumonia. Also recognized as an emerging zoonotic agent, it is responsible for outbreaks of human infections in Asian countries. Serotype 2 is the predominant isolate from diseased animals and humans. The aerosolization of S. suis in the air of swine confinement buildings (SCB) was studied. The presence of S. suis in bioaerosols was monitored in SCB where cases of infection had been reported and in healthy SCB without reported infections. Using a quantitative-PCR (qPCR) method, we determined the total number of bacteria (1 × 108 to 2 × 108 airborne/m3), total number of S. suis bacteria (4 × 105 to 10 × 105 airborne/m3), and number of S. suis serotype 2 and 1/2 bacteria (1 × 103 to 30 × 103 airborne/m3) present in the air. S. suis serotypes 2 and 1/2 were detected in the air of all growing/finishing SCB that had documented cases of S. suis infection and in 50% of healthy SCB. The total number of bacteria and total numbers of S. suis and S. suis serotype 2 and 1/2 bacteria were monitored in one positive SCB during a 5-week period, and it was shown that the aerosolized S. suis serotypes 2 and 1/2 remain airborne for a prolonged period. When the effect of aerosolization on S. suis was observed, the percentage of intact S. suis bacteria (showing cell membrane integrity) in the air might have been up to 13%. Finally S. suis was found in nasal swabs from 14 out of 21 healthy finishing-SCB workers, suggesting significant exposure to the pathogen. This report provides a better understanding of the aerosolization, prevalence, and persistence of S. suis in SCB