String cosmology versus standard and inflationary cosmology

This paper presents a review of the basic, model-independent differences between the pre-big bang scenario, arising naturally in a string cosmology context, and the standard inflationary scenario. We use an unconventional approach in which the introduction of technical details is avoided as much as possible, trying to focus the reader's attention on the main conceptual aspects of both scenarios. The aim of the paper is not to conclude in favour either of one or of the other scenario, but to raise questions that are left to the reader's meditation. Warnings: the paper does not contain equations, and is not intended as a complete review of all aspects of string cosmology.Comment: 22 pages, Latex (IOP Style), three figures included using epsfig. To appear in Class. Quantum Grav. (Topical Review Section). Two misprints correcte

Experimental campylobacter jejuni infection of scid mice

Campylobacter jejuni was inoculated orally to C.B-17 scid/scid (severe combined immunodeficient) and C.B—17 immunocompetent mice. Groups of mice from each strain were pretreated with enrofloxacin in an attempt to increase colonisation. All mice were heavily colonised but neither clinical signs of illness nor histological lesions were observed. Results from our experiment indicate that specific humoral and cellular immunity are not directly involved in the protection against C. jejuni, since said mice were not more sensitive to the infection than C.B-17 rnice. Animals, treated as well as untreated with antibiotic, showed the same colonisation pattern which suggests that normal flora does not hamper establishing of this bacterium in the intestine. On the other hand this study shows that both C.B~l7 and scid mice may become inapparent carriers of C. jejuni