3,188 research outputs found
Nonlinear and evolutionary phenomena in deterministic growing economies
We discuss the implications of nonlinearity in competitive models of optimal
endogenous growth. Departing from a simple representative agent setup with
convex risk premium and investment adjustment costs, we define an open economy
dynamic optimization problem and show that the optimal control solution is given
by an autonomous nonlinear vector field in <3 with multiple equilibria and no optimal
stable solutions. We give a thorough analytical and numerical analysis of this
system qualitative dynamics and show the existence of local singularities, such as
fold (saddle-node), Hopf and Fold-Hopf bifurcations of equilibria. Finally, we discuss
the policy implications of global nonlinear phenomena. We focus on dynamic
scenarios arising in the vicinity of Fold-Hopf bifurcations and demonstrate the existence
of global dynamic phenomena arising from the complex organization of the
invariant manifolds of this system. We then consider this setup in a non-cooperative
differential game environment, where asymmetric players choose open loop no feedback
strategies and dynamics are coupled by an aggregate risk premium mechanism.
When only convex risk premium is considered, we show that these games have a
specific state-separability property, where players have optimal, but naive, beliefs
about the evolution of the state of the game. We argue that the existence of optimal
beliefs in this fashion, provides a unique framework to study the implications
of the self-confirming equilibrium (SCE) hypothesis in a dynamic game setup. We
propose to answer the following question. Are players able to concur on a SCE,
where their expectations are self-fulfilling? To evaluate this hypothesis we consider
a simple conjecture. If beliefs bound the state-space of the game asymptotically
and strategies are Lipschitz continuous, then it is possible to describe SCE solutions
and evaluate the qualitative properties of equilibrium. If strategies are not smooth,
which is likely in environments where belief-based solutions require players to learn
a SCE, then asymptotic dynamics can be evaluated numerically as a Hidden Markov
Model (HMM). We discuss this topic for a class of games where players lack the
relevant information to pursue their optimal strategies and have to base their decisions
on subjective beliefs. We set up one of the games proposed as a multi-objective
optimization problem under uncertainty and evaluate its asymptotic solution as a
multi-criteria HMM.We show that under a simple linear learning regime there is convergence
to a SCE and portray strong emergence phenomena as a result of persistent
uncertainty
Avaliação de genótipos de mandioca em diferentes épocas de colheita no estado do Acre.
No Estado do Acre, a mandioca tem grande importância econômica e social, constituindo-se num dos principais produtos básicos da alimentação da população, principalmente na forma de farinha, mas com grande potencial também para o consumo in natura. O objetivo deste trabalho foi avaliar genótipos de mandioca em diferentes épocas de colheita no Estado do Acre. Foram avaliados dez genótipos de mandioca em quatro épocas de colheita utilizando o delineamento de blocos casualizados com quatro repetições, em esquema de parcelas subdivididas, sendo as épocas as parcelas e os genótipos as subparcelas, nas safras 1999/2000 e 2000/2001. Os genótipos MD-33 e Pão apresentaram alto rendimento de raÃzes e resistência à podridão radicular; o primeiro é indicado para a industrialização e o segundo para o consumo in natura. A colheita aos 14 meses após o plantio proporcionou o maior rendimento de raÃzes, mas apresentou maior incidência de podridão radicular. O teor de amido e a incidência de podridão radicular variaram em razão dos genótipos e épocas de colheita avaliados
PIBID música e prática pedagógico-musical: experiências de ensino envolvendo cotidiano e prática musical
Anais do II Seminário Seminário Estadual PIBID do Paraná: tecendo saberes / organizado por Dulcyene Maria Ribeiro e Catarina Costa Fernandes — Foz do Iguaçu: Unioeste; Unila, 2014O trabalho apresenta a experiência de atuação no subprojeto de Música do PIBID da
Universidade Estadual de Ponta Grossa, realizado em uma escola da rede pública de ensino do
municÃpio, e tem como principal objetivo discutir duas atividades realizadas, sendo uma sobre ‘Rock e
os elementos formais do som’ e a outra referente a uma experiência de prática musical com os alunos,
que integrava canto, violão, percussão e flauta. Foi possÃvel avaliar que a maioria dos alunos
conseguiu assimilar o conteúdo mais efetivamente por ter sido trabalhado com recursos que fazem
parte do seu cotidiano e por ser um contexto mais próximo da sua realidade auditiva. Os momentos de
prática musical proporcionaram reflexões sobre a importância do planejamento no momento da
realização das atividades e a necessidade deste ser flexÃvel e estar elaborado detalhadament
Caffeine, adenosine receptors, and synaptic plasticity
Copyright ©2012 IOS Press All rights reserved.Few studies to date have looked at the effects of caffeine on synaptic plasticity, and those that did used very high
concentrations of caffeine, whereas the brain concentrations attained by regular coffee consumption in humans should be in the low micromolar range, where caffeine exerts pharmacological actions mainly by antagonizing adenosine receptors. Accordingly, rats drinking caffeine (1 g/L) for 3 weeks, displayed a concentration of caffeine of circa 22 μM in the hippocampus. It is known that selective adenosine A1 receptor antagonists facilitate, whereas selective adenosine A2A receptor antagonists attenuate, long term potentiation (LTP) in the hippocampus. Although caffeine is a non-selective antagonist of adenosine receptors, it attenuates frequency-induced LTP in hippocampal slices in a manner similar to selective adenosine A2A receptor antagonists. These effects of low micromolar concentration of caffeine (30 μM) are maintained in aged animals, which is important when a possible beneficial effect for caffeine in age-related cognitive decline is proposed. Future studies will still be required to confirm and detail the involvement of A1 and A2A receptors in the effects of caffeine on hippocampal synaptic plasticity, using both pharmacological and genetic approaches.The work was supported by Fundação para a Ciência e Tecnologia and Fundação
Oriente
Caracterização de raÃzes e da qualidade da massa de genótipos de mandioca para consumo in natura no estado do Acre.
A cultura da mandioca apresenta expressiva importância social e econômica para o Estado do Acre. A cultura é tipicamente explorada por milhares de pequenos produtores sendo parte da produção usada na subsistência e outra como fonte de renda obtida com a venda principalmente da farinha
Composição botânica da dieta consumida por bovinos em pastagens de quicuio-da-amazônia (Brachiaria humidicola) através da analise microhistologica de fezes em área de pequeno produtor da Zona Bragantina.
Utilização, em pastejo, de aveia semeada sobre capim-tanzânia, para complementação da dieta de vacas de alta produção na época da seca: resposta bioeconômica.
bitstream/CPPSE/16798/1/boletimp-d-3.pd
Purinergic P2 receptors trigger adenosine release leading to adenosine A2A receptor activation and facilitation of long-term potentiation in rat hippocampal slices
Electrophysiological recordings were used to investigate the effects of ATP analogues on [theta]-burst-induced long-term potentiation (LTP) in rat hippocampal slices. [alpha],[beta]-Methylene ATP ([alpha],[beta]-MeATP; 20 [mu]M) decreased LTP from 36±9% to 17±5%, an effect prevented by adenosine A1 receptor blockade in accordance with the localised catabolism of ATP analogues into adenosine, leading to adenosine A1 receptor activation. Thus, to probe the role of extracellular ATP, all experiments were performed with the A1 receptor selective antagonist, 1,3-dipropyl-8-cyclopentylxanthine (50 nM). In these conditions, [alpha],[beta]-MeATP or 5'-adenylylimido-diphosphate ([beta],[gamma]-ImATP; 20 [mu]M) facilitated LTP by 120%, an effect prevented by the P2 receptor antagonists, pyridoxalphosphate-6-azophenyl-2'-4'-disulphonic acid (PPADS; 20 [mu]M) or suramin (75 [mu]M), as well as by the P2X1/3-selective antagonist 8-(benzamido)naphthalene-1,3,5-trisulfonate (10 [mu]M). The facilitations of LTP by either [alpha],[beta]-MeATP or [beta],[gamma]-ImATP (20 [mu]M) were also prevented by both 4-(2-[7-amino-2-(2-furyl(1,2,4)-triazolo(2,3a)-(1,3,5)triazin-5-yl-amino]ethyl)phenol (50 nM) or 7-2(-phenylethyl)-5-amino-2-(2-furyl)-pyrazolo-[4,3-e]-1,2,4-triazolo[1,5-c] pyrimidine (50 nM), antagonists of facilitatory adenosine A2A receptors, were occluded by the A2A receptor agonist, CGS 21680 (10 nM) and were prevented by the protein kinase C inhibitor, chelerythrine (6 [mu]M) and unaffected by the protein kinase A inhibitor, H89 (1 [mu]M). Furthermore, [beta],[gamma]-ImATP (20 [mu]M) enhanced [3H]adenosine outflow from rat hippocampal slices by nearly 150%, an effect prevented by PPADS (20 [mu]M) or suramin (75 [mu]M). The adenosine transport inhibitors, nitrobenzylthioinosine (5 [mu]M) and dipyridamole (10 [mu]M) also prevented [beta],[gamma]-ImATP (20 [mu]M)-induced [3H]adenosine outflow and facilitation of LTP. These results suggest that ATP analogues facilitate LTP through P2 receptor activation that mainly triggers adenosine release leading to the activation of adenosine A2A receptors.http://www.sciencedirect.com/science/article/B6T0F-49SFDNY-1/1/bd15c287ddd50f5af9c1be35dcb9227
- …