Perturbations in the Ekpyrotic Scenarios

With the new cosmological data gathered over the last few years, the inflationary paradigm has seen its predictions largely unchallenged. A recent proposal, called the ekpyrotic scenario, was argued to be a viable competitor as it was claimed that the spectrum of primordial perturbations it produces is scale invariant. By investigating closely this scenario, we show that the corresponding spectrum depends explicitly on an arbitrary function of wavenumber and is therefore itself arbitrary. It can at will be set scale invariant. We conclude that the scenario is not predictive at this stage.Comment: 4 pages, no figure, uses moriond.sty, to appear in the proceeding of the Moriond cosmology meeting held at Les Arcs, France (March 16-23, 2002

Métodos de fracionamento e caracterização da matéria orgânica do solo.

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TLR4 and NLRP3 Caspase 1- IL-1β- Axis are not Involved in Colon Ascendens Stent Peritonitis (Casp)-Associated Heart Disease

Hemodynamic collapse and myocardial dysfunction are among the major causes ofdeath in severe sepsis. The purpose of this study was to assess the role played by TLR4and by the NLRP3 inflammasome in the cardiac dysfunction that occurs after highgradepolymicrobial sepsis. We performed the colon ascendens stent peritonitis (CASP)surgery in Tlr4-/-, Nlrp3-/- and caspase-1-/- mice. We also assessed for the first time theelectrical heart function in the CASP model. The QJ interval was increased in wild-typeC57BL/6J mice after CASP when compared to sham controls, a result paralleled by anincrease in the cardiac action potential duration (APD). The decreases in ejectionfraction (EF), left-ventricle end diastolic volume (LVEDV), stroke volume, and cardiacoutput found after CASP were similar among all groups of mice. Similar heart responsewas found when Nlrp3-/- mice were submitted to high-grade CLP. Despite developingcardiac dysfunction similar to wild-types after CASP, Nlrp3-/- mice had reducedcirculating levels of IL-1β, IL-6 and TNF-α. Our results demonstrate that the geneticablation of Tlr4, Nlrp3, and caspase-1 does not prevent the cardiac dysfunction, despitepreventing the increase in pro-inflammatory cytokines, indicating that these are notfeasible targets to therapy in high-grade sepsis.Fil: López Alarcón, Maria Micaela. Universidade Federal do Rio de Janeiro; BrasilFil: Fernandez Ruocco, Maria Julieta. Universidade Federal do Rio de Janeiro; BrasilFil: Ferreira, Fabiano. Universidade Federal do Rio de Janeiro; BrasilFil: Paula Neto, Heitor A.. Universidade Federal do Rio de Janeiro; BrasilFil: Sepúlveda, Marisa Noemí. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Investigaciones Cardiovasculares ; ArgentinaFil: Vila Petroff, Martin Gerarde. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Investigaciones Cardiovasculares ; ArgentinaFil: Carvalho, Adriana Bastos. Universidade Federal do Rio de Janeiro; BrasilFil: Peroba Ramos, Isalira. Universidade Federal do Rio de Janeiro; BrasilFil: Branda, Hugo Justino. Universidade Federal do Rio de Janeiro; BrasilFil: Neto Paiva, Claudia. Universidade Federal do Rio de Janeiro; BrasilFil: Medei, Emiliano. Universidade Federal do Rio de Janeiro; Brasi