Consider a general equilibrium framework where the marginal cost of extraction from several deposits of an exhaustible resource is constant in terms of an inexhaustible perfect substitute and differs between deposits. The instantaneous rate of production from the inexhaustible resource is subject to a capacity constraint. We show, under standard assumptions, that not only may it be optimal to begin using a high cost resource before a lower cost one is depleted, as shown in Kemp and Long (1980a), but it may be optimal to begin using it strictly before the lower cost one is even put into use. Thus the intuitive principle, derived from partial equilibrium analysis, that when the rate of discount is positive natural resources should always be exploited in strictly increasing order of costs, not only does not hold in a general equilibrium context, but may be totally reversed.

Objective This article aims at explaining national medal totals at the 1992–2016 Summer Olympic Games (n = 1,289 observations) and forecasting them in 2016 (based on 1992–2012 data) and 2020 with a set of variables similar to previous studies, as well as a regional (subcontinents) variable not tested previously in the literature in English. Method Econometric testing not only resorts to a Tobit model as usual but also to a Hurdle model. Results Most variables have a significant impact on national team medal totals; it appears to be negative for most regions other than North America except Western Europe and Oceania (not significant). Then, two models (Tobit and Hurdle) are implemented to forecast national medal totals at the 2016 and 2020 Summer Olympics. Conclusion Both models are complementary for the 2016 forecast. The 2020 forecast is consistent with Olympic Medals Predictions, although some striking differences are found.

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This paper examines the link between pollution and income. The main purpose is to assess whether the introduction of income inequality in a Environmental Kuznets Curve (EKC) analysis can give new insights into the relationship between pollution and economic growth. The EKC hypothesis proposes that there is an inverted U-shape relation between environmental degradation and income per capita. We question this common result, in a simple model where the income inequality evolution is exogenous and where the planner could use only one instrument. For a set of parameter values we find, for example, a two-hump curve. JEL classification: D3, H4, Q2.Est-ce que le postulat de S. Kuznets remet en question les courbes environnementales a`la Kuznets? Cet article analyse la relation entre pollution et revenu. L'objectif de cet article est de montrer comment la prise en compte de l'ine´galite´des revenus, dans une analyse de la courbe environnementale de Kuznets, peut modifier la relation entre pollution et croissance. L'hypothe`se de la courbe environnementale de Kuznets revient a`supposer l'existence d'une forme en U inverse´entre la de´gradation de l'environnement et le revenu par teˆte. Cet article remet en cause ce re´sultat a`l'aide d'un mode`le simple dans lequel l'ine´galite´du revenu e´volue de manie`re exoge`ne et ou`le planificateur ne peut utiliser qu'un seul instrument. Pour certaines valeurs des parame`tres du mode`le nous trouvons que la relation entre la pollution et le revenu suit une courbe a`deux bosses.

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The idea here is to bring to light eventual discrimination against non-European households. We show that these households, all else held constant, spend more time on the waiting lists. Appropriate decomposition techniques enable us to demonstrate that a nonnegligible portion of this gap could well be due to discrimination.

Purpose This paper is the first of its kind to look at first-year undergraduates in France. The purpose of this paper is to measure the impact of holding down a job on the probability of students dropping out of higher education or passing their first year. Design/methodology/approach Given the existence of relevant unobserved explanatory variables, probit models with two simultaneous equations have been estimated. The first equation will enable us to explain paid employment or working hours, and the second academic outcomes that allow for dropout. Findings The results show that being employed means students are more likely to drop out during their first year and less likely to pass. The latter finding is comparable with results for subsequent academic years although the impact is greater for first-year undergraduates. The more intensive the work, the greater the adverse effects of employment. Originality/value By refining the research, this negative impact of employment is not verified for all the student profiles. For some of them, e.g., those with honours at the secondary bachelor, employment does not harm their academic results.

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