47 research outputs found
Neutrino Telescopes' Sensitivity to Dark Matter
The nature of the dark matter of the Universe is yet unknown and most likely
is connected with new physics. The search for its composition is under way
through direct and indirect detection. Fundamental physical aspects such as
energy threshold, geometry and location are taken into account to investigate
proposed neutrino telescopes of km^3 volume sensitivities to dark matter. These
sensitivities are just sufficient to test a few WIMP scenarios. Telescopes of
km^3 volume, such as IceCube, can definitely discover or exclude superheavy (M
> 10^10 GeV) Strong Interacting Massive Particles (Simpzillas). Smaller
neutrino telescopes such as ANTARES, AMANDA-II and NESTOR can probe a large
region of the Simpzilla parameter space.Comment: 28 pages, 9 figure
Limits to the muon flux from WIMP annihilation in the center of the Earth with the AMANDA detector
A search for nearly vertical up-going muon-neutrinos from neutralino
annihilations in the center of the Earth has been performed with the AMANDA-B10
neutrino detector. The data sample collected in 130.1 days of live-time in
1997, ~10^9 events, has been analyzed for this search. No excess over the
expected atmospheric neutrino background is oberved. An upper limit at 90%
confidence level on the annihilation rate of neutralinos in the center of the
Earth is obtained as a function of the neutralino mass in the range 100
GeV-5000 GeV, as well as the corresponding muon flux limit.Comment: 14 pages, 11 figures. Version accepted for publication in Physical
Review
Effect of potentially probiotic lactobacilli on faecal enzyme activity in minipigs on a high-fat, high-cholesterol diet - A preliminary in vivo trial
Minipigs were fed a "Western-style", high-cholesterol diet for a baseline period, followed by the diet containing a mixture of three Lactobacillus strains with potential probiotic features, after which a normal pig diet was followed. The faecal enzyme activity for β-glucuronidase and azoreductase, which are commonly considered as markers for procarcinogenic activity, was significantly reduced during the 5 weeks of "probiotic" supplementation. During the period of Lactobacillus administration, the cell counts for total anaerobes increased, whereas the total number of aerobes showed no change. © 2003 Elsevier Science B.V. All rights reserved.Articl
Characterisation and selection of probiotic lactobacilli for a preliminary minipig feeding trial and their effect on serum cholesterol levels, faeces pH and faeces moisture content
Three out of 297 Lactobacillus strains isolated from pig faeces were selected for a feeding trial on account of their high bile-salt hydrolase (BSH) activity, bile-salt resistance, low pH tolerance and the production of antimicrobial substances. Two strains were identified as Lactobacillus johnsonii and one as Lactobacillus reuteri by DNA-DNA hybridisation. L. johnsoniii BFE 1061 produced a bacteriocin active against a range of lactic acid bacteria (LAB) and nonrelated bacteria including Clostridium perfringens. Six minipigs were maintained on a high-fat, high-cholesterol ('Western Style') diet for 17 weeks after which the diet was supplemented with the 'probiotic mixture' containing the above mentioned three Lactobacillus strains at 2 x 1012 CFU per pig per day for five weeks. The mixture was given as a resuspended lyophilisate. During a two week follow-up period the minipigs received only the 'Western-style' diet without probiotic supplementation. A lowering effect on serum cholesterol levels was indicated after three weeks probiotic feeding, concomitant with an increase in the moisture content of the faeces and Lactobacillus cell numbers. Triglycerides, pH and number of lactic acid bacteria in faeces were not significantly influenced by probiotic supplementation.Articl