Anomaly-induced effective action and Chern-Simons modification of general relativity

Recently it was shown that the quantum vacuum effects of massless chiral fermion field in curved space-time leads to the parity-violating Pontryagin density term, which appears in the trace anomaly with imaginary coefficient. In the present work the anomaly-induced effective action with the parity-violating term is derived. The result is similar to the Chern-Simons modified general relativity, which was extensively studied in the last decade, but with the kinetic terms for the scalar different from those considered previously in the literature. The parity-breaking term makes no effect on the zero-order cosmology, but it is expected to be relevant in the black hole solutions and in the cosmological perturbations, especially gravitational waves.Comment: 15 pages, LaTeX, no Figures. Two references added, correction in the Acknowledgements. Fits the manuscript accepted in Physics Letters

Inhibition by ATP of hippocampal synaptic transmission requires localized extracellular catabolism by ecto-nucleotidases into adenosine and channeling to adenosine A1 receptors

© 1998 Society for NeuroscienceATP analogs substituted in the γ-phosphorus (ATPγS, β, γ-imido-ATP, and β, γ-methylene-ATP) were used to probe the involvement of P2 receptors in the modulation of synaptic transmission in the hippocampus, because their extracellular catabolism was virtually not detected in CA1 slices. ATP and γ-substituted analogs were equipotent to inhibit synaptic transmission in CA1 pyramid synapses (IC50 of 17–22 μM). The inhibitory effect of ATP and γ-phosphorus-substituted ATP analogs (30 μM) was not modified by the P2 receptor antagonist suramin (100 μM), was inhibited by 42–49% by the ecto-5’- nucleotidase inhibitor and α, β-methylene ADP (100 μM), was inhibited by 74–85% by 2 U/ml adenosine deaminase (which converts adenosine into its inactive metabolite-inosine), and was nearly prevented by the adenosine A1 receptor antagonist 1,3-dipropyl-8-cyclopentylxanthine (10 nM). Stronger support for the involvement of extracellular adenosine formation as a main requirement for the inhibitory effect of ATP and γ-substituted ATP analogs was the observation that an inhibitor of adenosine uptake, dipyridamole (20 μM), potentiated by 92–124% the inhibitory effect of ATP and γ-substituted ATP analogs (10 μM), a potentiation similar to that obtained for 10 μM adenosine (113%). Thus, the present results indicate that inhibition by extracellular ATP of hippocampal synaptic transmission requires localized extracellular catabolism by ectonucleotidases and channeling of the generated adenosine to adenosine A1 receptors.This work was supported by Junta Nacional de Investigação Cientifica e Tecnológica, Praxis XXI, Gulbenkian Foundation, and European Union (BIOMED 2 programme

Engenheiros técnicos: que formação?

A minha comunicação vai incidir, fundamentalmente, sobre as medidas a tomar pelas Escolas Superiores de Engenharia perante a recente alteração da Lei de Bases do Sistema Educativo tendo por base uma breve reflexão sobre a minha experiência, vivida numa Escola jovem, com formação nesta área, que é a Escola Superior de Tecnologia de Viseu Esta Escola, tal como as suas congéneres entretanto criadas em Portugal, surgiu, entre outros, com o objectivo de formar técnicos superiores necessários aos diversos sectores de actividade da sua área de influência tendo em vista o desenvolvimento sustentado da região e do País

Famílias, estratégias educativas e percursos escolares

The extension of compulsory schooling during the last decades raises to the sociological research on social inequalities in education the need for a questioning on the transformations that have been reconfiguring the complex social processes produced by the development of contemporary educational systems. Based on an approach informed by non-deterministic explicative models, the text tries to understand such frame of complexity and opacity. To accomplish it, and taking as reference the results of a sociological research developed in three school contexts of Lisbon, the text focus on the actions and educational strategies of the families of the researched contexts and demonstrates that traditional oppositions in the relation with school have transformed in a frame of differentiation of school values, attitudes and trajectorie

Covid-19: A Different Economic Crisis but the Same Paradigm of Democratic Deficit in the EU

Based on a normative orientation and an interdisciplinary perspective, this is a comparative study, using the process tracing methodology, between the EU responses to Eurozone and Covid-19 crises to assess if, despite different outcomes, institutional decision-making processes evidence a change. The study concluded that the EU democratic deficit remains, which assumes special features in economic crises, providing a political oversize power to the economically hegemonic states, thus constraining ideological debate and making national interest prevail over politicisation. This perpetuates the conversion of structural economic positions into political power at the expense of political representative power and democracy