24,897 research outputs found
Pitfalls and potential of institutional change: Rain-index insurance and the sustainability of rangeland management
No full textRain-index insurance is strongly advocated in many parts of the developing world to help farmers to cope with climatic risk that prevail in (semi-)arid rangelands due to low and highly uncertain rainfall. We present a modeling analysis of how the availability of rain-index insurance affects the sustainability of rangeland management. We show that a rain-index insurance with frequent payos, i.e. a high strike level, leads to the choice of less sustainable grazing management than without insurance available. However, a rain-index insurance with a low to medium strike level enhances the farmer's well-being while not impairing the sustainability of rangeland management.ecological-economic modeling, weather-index insurance, Namibia, grazing management, risk, sustainability, weather-based derivatives
Glucagon-stimulated but not isoproterenol-stimulated glucose formation inhibition by interleukin-6 in primary cultured rat hepatocytes
No full textDuring prolonged sepsis, impairment of glucose supply by the liver leads to hypoglycemia. Our aim was to investigate whether proinflammatory cytokine interleukin-6, a major mediator of the hepatic acute phase reaction, could contribute to this impairment by inhibiting hepatic glucose production stimulated by glucagon or isoproterenol in rat hepatocytes. Interleukin-6 inhibited the stimulation of glucose formation from glycogen by glucagon but not by isoproterenol in cultured rat hepatocytes. This was confirmed in the perfused rat liver. In cultured hepatocytes, the increase in cyclic adenosine-3',5'-monophosphate formation by glucagon was inhibited by interleukin-6, which was probably due to attenuation of glucagon binding to the glucagon receptor. The increase in cyclic adenosine-3',5'-monophosphate stimulated by isoproterenol was not affected by interleukin-6. However, the cytokine inhibited both expression of the key gluconeogenic control enzyme, phosphoenolpyruvate carboxykinase, stimulated by glucagon and isoproterenol. Thus, while increased glucose demand during the acute-phase reaction might initially be accomplished by catecholamine-mediated stimulation Of glucose formation from glycogen, inhibition of gluconeogenesis by interleukin-6 may contribute to the impairment of glucose homeostasis during the prolonged acute phase reaction
Diffusive atom transport along step edges on Ag(111) at 295 K
No full textThe entropy-driven relaxation of a unique, non-equilibrium step edge configuration on the Ag(111) surface was observed using time-resolved STM imaging at room temperature. Using the Gibbs-Thomson relation, the relaxation process is quantitatively described as diffusive mass transport in terms of a gradient in the chemical potential along the monoatomic step edge. The STM data directly show that mass transport on Ag(111) is dominated by step edge diffusion at 295 K, and allow an estimate of the corresponding effective energy barrier. We obtain E-eff = 0.49 +/- 0.05 eV and compare this value with recent results on island diffusion studies. (C) 2003 Elsevier B.V. All rights reserved
A Hopf's lemma and a strong minimum principle for the fractional p-Laplacian
No full textOur propose here is to provide a Hopf lemma and a strong minimum principle for weak supersolutions of (−Δp)su=c(x)|u|p−2u in Ω where Ω is an open set of RN, s∈(0,1), p∈(1,+∞), c∈C(Ω‾) and (−Δp)s is the fractional p-Laplacian.Fil: del Pezzo, Leandro Martin. Universidad Torcuato Di Tella; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Quaas, Alexander. Universidad Técnica Federico Santa María; Chil
Sustainability economics: General versus specific, and conceptual versus practical
No full textWe clarify the definition and interpretation of 'sustainability economics' (Baumgärtner and Quaas 2010) in response to recent comments by van den Bergh (2010), Bartelmus (2010) and others. For that sake, we distinguish between general and specific definitions of sustainability and sustainability economics, as well as between conceptual and practical approaches
Spectrum of the fractional p-Laplacian in RN and decay estimate for positive solutions of a Schrödinger equation
No full textIn this paper, we prove the existence of unbounded sequence of eigenvalues for the fractional p−Laplacian with weight in RN. We also show a nonexistence result when the weight has positive integral. In addition, we show some qualitative properties of the first eigenfunction including a sharp decay estimate. Finally, we extend the decay result to the positive solutions of a Schrödinger type equation.Fil: del Pezzo, Leandro Martin. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Torcuato Di Tella. Departamento de Matemáticas y Estadística; ArgentinaFil: Quaas, Alexander. Universidad Técnica Federico Santa María; Chil
Non-resonant Fredholm alternative and anti-maximum principle for the fractional p-Laplacian
No full textIn this paper we extend two nowadays classical results to a nonlinear Dirichlet problem to equations involving the fractional p-Laplacian. The first result is an existence in a non-resonant range more specific between the first and second eigenvalue of the fractional p-Laplacian. The second result is the anti-maximum principle for the fractional p-Laplacian.Fil: del Pezzo, Leandro Martin. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Matemática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Quaas, Alexander. Universidad Técnica Federico Santa María. Departamento de Matemática; Chil
Sustainability economics -- General versus specific, and conceptual versus practical
No full textWe clarify the definition and interpretation of "sustainability economics" (Baumgärtner and Quaas, 2010) in response to recent comments by van den Bergh (2010), Bartelmus (2010) and others. For that sake, we distinguish between general and specific definitions of sustainability and sustainability economics, as well as between conceptual and practical approaches.Economic and environmental accounting Efficiency Externality Joint production Justice Stocks Sustainability economics
Global bifurcation for fractional p-Laplacian and an application
No full textWe prove the existence of an unbounded branch of solutions to the nonlinear non-local equation (Equation presented) bifurcating from the first eigenvalue. Here (-Δ)s p denotes the fractional p-Laplacian and Ω ⊂ ℝ1 is a bounded regular domain. The proof of the bifurcation results relies in computing the Leray-Schauder degree by making an homotopy respect to s (the order of the fractional p-Laplacian) and then to use results of local case (that is s = 1) found in the paper of del Pino and Manasevich [J. Diff. Equ. 92(1991) (2), 226-251]. Finally, we give some application to an existence result.Fil: del Pezzo, Leandro Martin. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Quaas, Alexander. Universidad Técnica Federico Santa María; Chil
Bush encroachment control and risk management in semi-arid rangelands
No full textWe study the role of bush encroachment control for a farmer’s income and income risk in a stochastic ecological-economic model of grazing management in semiarid rangelands. In particular, we study debushing as an instrument of risk management that complements the choice of an adaptive grazing management strategy for that sake. We show that debushing, while being a good practice for increasing the mean pasture productivity and thus expected income, also increases the farmer’s income risk. The optimal extent of debushing for a risk-averse farmer is thus determined from balancing the positive and negative consequences of debushing on intertemporal and stochastic farm income.bush encroachment, expected utility, farm income, intertemporal optimization, risk aversion, risk management, semi-arid rangeland
- …
