Quantum state-dependent diffusion and multiplicative noise: a microscopic approach

The state-dependent diffusion, which concerns the Brownian motion of a particle in inhomogeneous media has been described phenomenologically in a number of ways. Based on a system-reservoir nonlinear coupling model we present a microscopic approach to quantum state-dependent diffusion and multiplicative noise in terms of a quantum Markovian Langevin description and an associated Fokker-Planck equation in position space in the overdamped limit. We examine the thermodynamic consistency and explore the possibility of observing a quantum current, a generic quantum effect, as a consequence of this state-dependent diffusion similar to one proposed by B\"{u}ttiker [Z. Phys. B {\bf 68}, 161 (1987)] in a classical context several years ago.Comment: To be published in Journal of Statistical Physics 28 pages, 3 figure

Characterisation of silent and active genes for a variable large protein of Borrelia recurrentis

BACKGROUND: We report the characterisation of the variable large protein (vlp) gene expressed by clinical isolate A1 of Borrelia recurrentis; the agent of the life-threatening disease louse-borne relapsing fever. METHODS: The major vlp protein of this isolate was characterised and a DNA probe created. Use of this together with standard molecular methods was used to determine the location of the vlp1(B. recurrentis A1) gene in both this and other isolates. RESULTS: This isolate was found to carry silent and expressed copies of the vlp1(B. recurrentis A1) gene on plasmids of 54 kbp and 24 kbp respectively, whereas a different isolate, A17, had only the silent vlp1(B. recurrentis A17) on a 54 kbp plasmid. Silent and expressed vlp1 have identical mature protein coding regions but have different 5' regions, both containing different potential lipoprotein leader sequences. Only one form of vlp1 is transcribed in the A1 isolate of B. recurrentis, yet both 5' upstream sequences of this vlp1 gene possess features of bacterial promoters. CONCLUSION: Taken together these results suggest that antigenic variation in B. recurrentis may result from recombination of variable large and small protein genes at the junction between lipoprotein leader sequence and mature protein coding region. However, this hypothetical model needs to be validated by further identification of expressed and silent variant protein genes in other B. recurrentis isolates

Typhoid fever

No Abstract. Journal of Ethiopian Medical Journal Vol. 3(2) 2002: pp. 100-10

Acute bacterial meningitis

No Abstract

Assessment of risk behaviours and factors associated with oral and peri-oral lesions in adult HIV patients at Tikur Anbessa Specialized Hospital, Addis Ababa, Ethiopia

No Abstract.Ethiopian Journal of Health Development Vol. 22 (2) 2008 pp. 180-18