Accelerating Cold Dark Matter Cosmology (ΩΛ≡0\Omega_{\Lambda}\equiv 0)

A new kind of accelerating flat model with no dark energy that is fully dominated by cold dark matter (CDM) is investigated. The number of CDM particles is not conserved and the present accelerating stage is a consequence of the negative pressure describing the irreversible process of gravitational particle creation. A related work involving accelerating CDM cosmology has been discussed before the SNe observations [Lima, Abramo & Germano, Phys. Rev. D53, 4287 (1996)]. However, in order to have a transition from a decelerating to an accelerating regime at low redshifts, the matter creation rate proposed here includes a constant term of the order of the Hubble parameter. In this case, $H_0$ does not need to be small in order to solve the age problem and the transition happens even if the matter creation is negligible during the radiation and part of the matter dominated phase. Therefore, instead of the vacuum dominance at redshifts of the order of a few, the present accelerating stage in this sort of Einstein-de Sitter CDM cosmology is a consequence of the gravitational particle creation process. As an extra bonus, in the present scenario does not exist the coincidence problem that plagues models with dominance of dark energy. The model is able to harmonize a CDM picture with the present age of the universe, the latest measurements of the Hubble parameter and the Supernovae observations.Comment: 9 pages, 6 figures, typos corrected, references added, discussion in Appendix B extende

Charge densities and charge noise in mesoscopic conductors

We introduce a hierarchy of density of states to characterize the charge distribution in a mesoscopic conductor. At the bottom of this hierarchy are the partial density of states which represent the contribution to the local density of states if both the incident and the out-going scattering channel is prescribed. The partial density of states play a prominent role in measurements with a scanning tunneling microscope on multiprobe conductors in the presence of current flow. The partial density of states determine the degree of dephasing generated by a weakly coupled voltage probe. In addition the partial density of states determine the frequency-dependent response of mesoscopic conductors in the presence of slowly oscillating voltages applied to the contacts of the sample. The partial density of states permit the formulation of a Friedel sum rule which can be applied locally. We introduce the off-diagonal elements of the partial density of states matrix to describe charge fluctuation processes. This generalization leads to a local Wigner-Smith life-time matrix.Comment: 10 pages, 2 figure

Avaliação do teor de carotenóides totais e compostos cianogênicos em farinha de raspa.

Este trabalho teve por objetivo avaliar o teor de carotenoides totais, compostos cianogênicos e umidade na raiz de mandioca da variedade Jari e na farinha de raspa. A raiz in natura apresentou 81,0 ± 0,6% de umidade e a farinha de raspa 3,4 ± 0,8%. O teor de carotenoides totais foi 24,1 ± 2,2 µg g-1 na farinha de raspa e 6,9 ± 0,5 µg g-1 na raiz fresca. Os compostos cianogênicos apresentaram valores próximos para a raiz in natura e processada, 7,9 ± 1,3 µg de HCN g-1 e 8,2 ± 2,1 µg de HCN g-1, respectivamente.PDF. T101

Levantamento de vírus de plantas no Estado do Acre.

São escassas as informações sobre vírus presentes naturalmente infetando plantas cultivadas ou não, no Estado do Acre. A fim de complementar estas parcas informações, foi realizada uma viagem de levantamento de viroses nos municípios de Cruzeiro do Sul, Mâncio Lima, Guajará e arredores (Pè da Terra, AC, Badejo do Meio, AM), Rio Branco e Xapurí, como parte do Programa Biota da Fapesp, em Outubro, 2018

Caracterização de posturas de Bactrocera carambolae Drew & Hancock em frutos de carambola.

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