Tilted cosmological models of Bianchi type V

Abstract

Cosmological models of Bianchi type V and I containing a perfect fluid with a linear equation of state plus cosmological constant are investigated using a tetrad approach where our variables are the Riemann tensor, the Ricci rotation coefficients and a subset of the tetrad vector components. This set, in the following called S, describes a spacetime when its elements are constrained by certain integrability conditions and due to a theorem by Cartan this set gives a complete local description of the spacetime. The system obtained by imposing the integrability conditions and Einstein's equations can be reduced to an integrable system of five coupled first order ordinary differential equations. The general solution is tilted and describes a fluid with expansion, shear and vorticity. With the help of standard bases for Bianchi V and I the full line element is found in terms of the elements in S. We then construct the solutions to the linearized equations around the open Friedmann model. The full system is also studied numerically and the perturbative solutions agree well with the numerical ones in the appropriate domains. We also give some examples of numerical solutions in the non-perturbative regime.

The efficacy of a malarial antibody enzyme immunoassay for establishing the reinstatement status of blood donors potentially exposed to malaria

“…[12] found that 364 of 367 (99·2%) P. falciparum infections, and 325 of 432 (75·2%) P. vivax infections, were diagnosed within 6 months of arrival in the USA. Second, in a similar UK study of imported malaria, 1427 of 1434 (99·5%) P. falciparum and 543 of 829 (65·5%) P. vivax infections occurred within 6 months of arrival in the UK [13]. Available data on diagnoses from Western Australia for the period 1990 -2001 are consistent with these reports in that for P. falciparum , all 85 (100%) infections with falciparum malaria occurred within 6 months of arrival.…”

“…The P. vivax sensitivity, in particular, is markedly improved over the 50 -65% reported in previous studies [1,5]. This sensitivity estimate calculated in acute samples is conservative because our proposed policy mandates a 6-month delay before testing, negating the impact of the estimated 7-14 day serological window period observed in early infection [11][12][13].…”