Could be a link between non atopic asthma and HP infection?

A potential role of Helicobater Pylori (HP) infection in several extra-intestinal pathologies has been recently suggested. The aim of our study was to assess the role of serology positive for HP in atopic and non atopic infants and children affected by atopic dermatitis, urticaria, rhinitis and asthma. We included 615 children affected by atopic diseases. According to prick test positivity and age, we divided the patients into two groups: atopic or non-atopic patients and infants (0-2 years) or children (2-12 years). The serum levels of antibodies for H. pylori immunoglobulin G were measured by using an ELISA test. We found a not significant difference between group 1 and group 2 about atopy. There was a significant higher frequency of HP positive serology in older children. As for infants, a higher significant prevalence of HP positive serology was found in non-atopic patients. HP positive serology was significantly higher only in non-atopic infants affected by atopic dermatitis and urticaria than in atopic. In group 2, non atopic children shown a significant increase in the prevalence of HP serum positivity than atopic children. As for asthma, there was an higher prevalence of HP serology positive in non atopic asthmatic children group than in atopic asthmatics. On the contrary, the prevalence of positive HP serology was not significantly different between atopic and non atopic children affected by dermatitis, urticaria, and rhinitis. The present data confirm an inverse association between HP positive serology and atopy in both groups. However, the higher prevalence of positive HP serology was observed in non atopic asthmatics children than in atopic asthmatics. We could speculate that HP infection can favour non-atopic asthma onset.

Neptune's Story.

It is conjectured that Triton was captured from a heliocentric orbit as the result of a collision with what was then one of Neptune's regular satellites. The immediate post-capture orbit was highly eccentric with a semimajor axis a approximately 10(3)R(N) and a periapse distance rp that oscillated periodically above a minimum value of about 5R(N). Dissipation due to tides raised by Neptune in Triton caused Triton's orbit to evolve to its present state in less, similar10(9) years. For much of this time Triton was almost entirely molten. While its orbit was evolving, Triton cannibalized most of the regular satellites of Neptune and also perturbed Nereid, thus accounting for that satellite's highly eccentric and inclined orbit. The only regular satellites of Neptune that survived were those that formed well within 5R(N) and they move on inclined orbits as the result of chaotic perturbations forced by Triton. Neptune's arcs are confined around the corotation resonances of one of these inner satellites. The widths and lengths of the arcs imply that the satellite's radius is at least 30/(sin i)(2/3) kilometers for i less, similar 1, where i is the angle of inclination.

Periodic magnetorotational dynamo action as a prototype of nonlinear magnetic-field generation in shear flows.

The nature of dynamo action in shear flows prone to magnetohydrodynamc instabilities is investigated using the magnetorotational dynamo in Keplerian shear flow as a prototype problem. Using direct numerical simulations and Newton's method, we compute an exact time-periodic magnetorotational dynamo solution to three-dimensional dissipative incompressible magnetohydrodynamic equations with rotation and shear. We discuss the physical mechanism behind the cycle and show that it results from a combination of linear and nonlinear interactions between a large-scale axisymmetric toroidal magnetic field and nonaxisymmetric perturbations amplified by the magnetorotational instability. We demonstrate that this large-scale dynamo mechanism is overall intrinsically nonlinear and not reducible to the standard mean-field dynamo formalism. Our results therefore provide clear evidence for a generic nonlinear generation mechanism of time-dependent coherent large-scale magnetic fields in shear flows and call for new theoretical dynamo models. These findings may offer important clues to understanding the transitional and statistical properties of subcritical magnetorotational turbulence.