171 research outputs found

    Optimal Unemployment Insurance for Older Workers

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    This paper shows that optimal unemployment insurance contracts are age-dependent. Older workers have only a few years left on the labor market prior to retirement. This short horizon implies a more digressive replacement ratio. However, there is a sufficiently short distance to retirement for which flat unemployment benefits can be the optimal contract as the nearly retired unemployed workers rationally expect never to suffer from the punishment. This is why imposing a tax on the future job is particularly efficient in the context of older workers because the agency can now reward the job search by present employment subsidies. Moreover, we propose adopting a global approach to unemployment insurance by determining an optimal contract that integrates unemployment insurance and retirement pension systems.unemployment insurance, retirement, recursive contracts, moral hazard

    New information from fish diets on the importance of glassy flying squid (Hyaloteuthis pelagica) (Teuthoidea: Ommastrephidae) in the epipelagic cephalopod community of the tropical Atlantic Ocean

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    Squids of the family Ommastrephidae are a vital part of marine food webs and support major fisheries around the world. They are widely distributed in the open ocean, where they are among the most abundant in number and biomass of nektonic epipelagic organisms. In turn, seven of the 11 genera of this family (Dosidicus, Illex, Martialia, Nototodarus, Ommastrephes, Sthenoteuthis, and Todarodes) are heavily preyed upon by top marine predators, i.e., birds, mammals, and fish, and currently support fisheries in both neritic and oceanic waters (Roper and Sweeney, 1984; Rodhouse, 1997). Their commercial importance has made the large ommastrephids the target of many scientific investigations and their biology is consequently reasonably well-known (Nigmatullin et al., 2001; Zuyev et al., 2002; Bower and Ichii, 2005). In contrast, much less information is available on the biology and ecological role of the smaller, unexploited species of ommastrephids (e.g., Eucleoteuthis, Hyaloteuthis, Ornithoteuthis, and Todaropsis)

    Impact de la lipolyse intravasculaire des triglycérides (TG) sur le métabolisme myocardique chez le rat

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    Notre alimentation et notre santé sont à la base du métabolisme des différents substrats. La sélection des substrats énergétiques principalement utilisés, soit le glucose ou les acides gras (AG), est modulée entre autre par l'insuline, les niveaux de glycémie et la disponibilité des lipides circulants. Un excès d'apport d'AG aux organes est associé à une série de phénomènes physiopathologiques collectivement désignés par le terme"lipotoxicité". La lipotoxicité sous-tend le développement de la résistance à l'insuline et du diabète mellitus de type 2 (DMT2). Par ailleurs, il est à la base de dysfonctions organiques associées à cette pathologie, notamment la dysfonction du système cardiovasculaire et l'augmentation de la susceptibilité du myocarde diabétique au développement de l'insuffisance cardiaque. Une augmentation de l'apport myocardique d'AG pourrait être en cause dans la grande dépendance du coeur diabétique aux AG comme source pratiquement unique d'énergie. De plus, ceci pourrait mener à une diminution de l'utilisation du glucose au niveau cardiaque, augmentant la susceptibilité du myocarde diabétique aux dommages ischémiques. L'apport tissulaire des AG est un processus très complexe. D'une part, les AG circulant liés à l'albumine plasmatique (acides gras libres--AGL) sont immédiatement disponibles aux tissus par diffusion simple ou facilitée, donc dépendant directement de la concentration circulante et du flot sanguin à l'organe. Le tissu adipeux est le siège du stockage et de la libération des AGL dans la circulation sanguine et ainsi régule la disponibilité de ces substrats aux autres organes. L'autre source d'AG disponible aux tissus, la lipolyse intravasculaire des triglycérides (LIVTG), est régulée par l'activité de la lipoprotéine lipase (LpL). Cette enzyme est présente à la surface luminale de l'endothélium des capillaires des tissus et hydrolyse les TG des chylomicrons et des lipoprotéines de très basse densité (VLDL). Or, le rôle précis joué par la LIVTG dans la régulation de l'utilisation in vivo des substrats énergétiques cardiaques dans les différentes conditions physiologiques et pathologiques n'est pas bien connu. En particulier, la contribution de cette source à la lipotoxicité cardiaque observée dans les états de résistance à l'insuline doit être davantage investiguée. Le but de ce présent mémoire est de mieux connaître le rôle que joue la LIVTG sur la sélection des substrats énergétiques cardiaques en condition normale et dans le DMT2. Nous avons utilisé le rat, un modèle animal chez lequel nous avons pu établir un DMT2 à l'aide d'une diète riche en fructose et en gras et d'une faible dose de streptozotocine. Nous avons inhibé la LIVTG à l'aide de l'injection intraveineuse de Triton WR1339, un détergent non-ionique inhibiteur de la LpL. Nous avons eu recours à des méthodes isotopiques conventionnelles mais aussi à la tomographie par émission de positrons (microTEP) afin de quantifier l'impact de la LIVTG sur le captage myocardique des AGL et des AG dérivés des TG, le flot sanguin coronarien, le métabolisme glucidique (MMRG) et oxydatif total (MVO 2 ) au niveau cardiaque. Ce mémoire a pour rôle de suggérer que la disponibilité des AG via la LIVTG régule de façon complexe l'utilisation des substrats énergétiques myocardiques in vivo chez le rat. Par ailleurs, nous avons pu établir un excellent modèle de DMT2 chez le rat. La disponibilité de ce modèle pourra nous permettre dans un futur rapproché d'examiner le rôle potentiel de la LIVTG dans la régulation du métabolisme énergétique cardiaque dans le DMT2

    Optimal unemployment insurance for older workers

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    At the end of working life, as well as reducing unemployment benefits, the unemployment-insurance agency could apply pension tax instead of wage tax. First, the pension tax provides greater incentives as the value of re-employment is tax-free.Second, the short job duration before retirement implies that the budgetary return and search incentives associated with the pension tax are considerable. By way of contrast, younger workers have greater search intensity and their future pension taxes are more remote and therefore more heavily-discounted: for them the wage tax is more efficient than is the pension tax. Finally, even in the special case where search intensity is zero close to retirement, perfect risk-sharing across unemployment and retirement is welfare-improving thanks to the pension tax

    Parametric Kalman filter for chemical transport models

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    A computational simplification of the Kalman filter (KF) is introduced – the parametric Kalman filter (PKF). The full covariance matrix dynamics of the KF, which describes the evolution along the analysis and forecast cycle, is replaced by the dynamics of the error variance and the diffusion tensor, which is related to the correlation length-scales. The PKF developed here has been applied to the simplified framework of advection–diffusion of a passive tracer, for its use in chemical transport model assimilation. The PKF is easy to compute and computationally cost-effective than an ensemble Kalman filter (EnKF) in this context. The validation of the method is presented for a simplified 1-D advection–diffusion dynamics

    Optimal Unemployment Insurance for Older Workers

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    This paper studies the optimal unemployment insurance for older workers in a repeated principal-agent model, where the search intensity of risk-averse workers (the agents) is not observed by the risk-neutral insurance agency (the principal). When unemployment benefits are the only available tool, the insurance agency is not able to induce older workers to search for a job. This is because of the short time-horizon of workers close to retirement. We propose to introduce a pension tax dependent on the length of the unemployment spell. We show that this device performs better than a wage tax after re-employment. First, it makes jobs more attractive, as they are free of tax. Second, because re-employment will be short-lived, a pension tax is a more powerful incentive than a wage tax, and provides more substantial fiscal gains to the agency. Finally, a pension tax allows those workers near retirement who still do not exercise job search to smooth their consumption during their unemployment spell, as if they could borrow against their future pension.Unemployment insurance; Retirement; Recursive contracts; Moral hazard

    Two-dimensional topological superconductivity in Pb/Co/Si(111)

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    Just like insulators can host topological Dirac states at their edges, superconductors can also exhibit topological phases characterized by Majorana edge states. Remarkable zero-energy states have been recently observed at the two ends of proximity induced superconducting wires, and were interpreted as localized Majorana end states in one-dimensional (1D) topological superconductor. By contrast, propagating Majorana states should exist at the 1D edges of two-dimensional (2D) topological superconductors. Here we report the direct observation of dispersive in-gap states surrounding topological superconducting domains made of a single atomic layer of Pb covering magnetic islands of Co/Si(111). We interpret the observed continuous dispersion across the superconducting gap in terms of a spatial topological transition accompanied by a chiral edge mode and residual gaped helical edge states. Our experimental approach enables the engineering and control of a large variety of novel quantum phases. This opens new horizons in the field of quantum materials and quantum electronics where the magnetization of the domains could be used as a control parameter for the manipulation of topological states.Comment: 12 pages, 3 figure

    Impact de la formation à l’enseignement et de l’encadrement sur le sentiment d’autoefficacité des nouveaux enseignants de cégep

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    This research assessed the effects of teacher training and supervision on new college teachers’ self-efficacy beliefs. A questionnaire, including a measurement scale of self-efficacy, was completed twice by 102 novice teachers. Analysis of the results leads to the conclusion that, if both pre-service and in-service trainings have some impact, supervision increases the most selfefficacy beliefs, more specifically regarding the teaching strategies, student engagement, and classroom management components.Keywords: Teacher training, educational support, self-efficacy belief, collegeCette recherche mesure l’impact de la formation à l’enseignement et de l’encadrement pédagogique sur le sentiment d’autoefficacité des nouveaux enseignants de cégep. Un questionnaire, incluant une échelle de mesure de ce sentiment, a été complété à deux reprises par 102 novices. L’analyse des résultats permet de conclure que si la formation créditée avant l’embauche et la formation non créditée après l’embauche ont un certain impact, c’est l’encadrement offert qui influence le plus le sentiment d’autoefficacité à l’égard des stratégies d’enseignement, de l’engagement des étudiants et de la gestion de classe.Mots-clés : Formation à l’enseignement, encadrement pédagogique, sentiment d’autoefficacité, cégep

    Tsukamurella tyrosinosolvens - An unusual case report of bacteremic pneumonia after lung transplantation

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    <p>Abstract</p> <p>Background</p> <p>Lung transplant recipients have an increased risk for actinomycetales infection secondary to immunosuppressive regimen.</p> <p>Case presentation</p> <p>A case of pulmonary infection with bacteremia due to <it>Tsukamurella tyrosinosolvens </it>in a 54-year old man who underwent a double lung transplantation four years previously is presented.</p> <p>Conclusion</p> <p>The identification by conventional biochemical assays was unsuccessful and <it>hsp </it>gene sequencing was used to identify <it>Tsukamurella tyrosinosolvens</it>.</p

    Long range coherent magnetic bound states in superconductors

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    The quantum coherent coupling of completely different degrees of freedom is a challenging path towards creating new functionalities for quantum electronics. Usually the antagonistic coupling between spins of magnetic impurities and superconductivity leads to the destruction of the superconducting order. Here we show that a localized classical spin of an iron atom immersed in a superconducting condensate can give rise to new kind of long range coherent magnetic quantum state. In addition to the well-known Shiba bound state present on top of an impurity we reveal the existence of a star shaped pattern which extends as far as 12 nm from the impurity location. This large spatial dispersion turns out to be related, in a non-trivial way, to the superconducting coherence length. Inside star branches we observed short scale interference fringes with a particle-hole asymmetry. Our theoretical approach captures these features and relates them to the electronic band structure and the Fermi wave length of the superconductor. The discovery of a directional long range effect implies that distant magnetic atoms could coherently interact leading to new topological superconducting phases with fascinating properties
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