2,027 research outputs found

    Singular quasilinear elliptic systems in RN\mathbb{R}^N

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    The existence of positive weak solutions to a singular quasilinear elliptic system in the whole space is established via suitable a priori estimates and Schauder's fixed point theorem

    On a Dirichlet problem with (p,q)(p,q)-Laplacian and parametric concave-convex nonlinearity

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    A homogeneous Dirichlet problem with (p,q)(p,q)-Laplace differential operator and reaction given by a parametric pp-convex term plus a qq-concave one is investigated. A bifurcation-type result, describing changes in the set of positive solutions as the parameter >0\lambda>0 varies, is proven. Since for every admissible \lambda the problem has a smallest positive solution u\bar u_{\lambda}, both monotonicity and continuity of the map u \lambda \mapsto \bar u_{\lambda} are studied.Comment: 12 pages, comments are welcom

    The strengths and failures of incentive mechanisms in notional defined contribution pension systems

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    Public pension systems based on the Notional Defined Contribution (NDC) principle were introduced during the 鈥90s in Italy, Sweden and Poland, among other countries. They mimic private savings, in that individuals get back, as pensioners, what they contributed to social security during working life, plus returns. As such, NDC systems should realize actuarial equity and incentive neutrality. However, when one considers the presence of NDC pensions together with minimum and social assistance pensions, this is no longer true. Indeed, in all the three countries considered, the NDC system shows a regressive feature, which disincentivizes contributions, particularly from low earners, who would be better off entering, or staying in, the shadow economy. In order to reduce the extent of this phenomenon, we examine the effects of introducing, or increasing, the possibility of accumulation of social assistance and NDC pensions, which would also improve pension adequacy. A complete accumulation of the two would solve the incentive problem, but would be costly and would require a structural reform of the pension system financing mechanism, altering the current balance between social contributions and general fiscal revenues. We show the effects of a change in the cumulation rules for social assistance and NDC pensions in Italy using CAPP_DYN, a population-based dynamic microsimulation model, which allows assessment of the evolution of the pension system in the coming decades and the distributional implications of such reform.

    How does a bicycle work? A new instrument to assess mechanical reasoning in school aged children

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    This study demonstrated that a brief interview can reveal the mechanical reasoning that could not be assessed via the Bicycle Drawing Test. This study, conducted on 190 children (6 to 11 years old), shows that mechanical reasoning improves with age. It shows correlations with spatial reasoning and motor control, and with visual reasonin

    Synthesis of organosiloxy: Transition metal polymers

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    The new compound, Mo(OSiPH3)4 (where Ph is C6H5) was synthesized. An overall chemical reaction which accounts for the observed products is given by the redox approach. Results indicate that Mo(OSiPH3)4 is thermally stable up to 230 C and relatively unreactive toward most common acids and bases even at elevated temperatures. Its behavior is not unlike that of Ti(OSiPH3)4