Prism adaptation and neck muscle vibration in healthy individuals: are two methods better than one?

Studies involving therapeutic combinations reveal an important benefit in the rehabilitation of neglect patients when compared to single therapies. In light of these observations our present work examines, in healthy individuals, sensorimotor and cognitive after-effects of prism adaptation and neck muscle vibration applied individually or simultaneously. We explored sensorimotor after-effects on visuo-manual open-loop pointing, visual and proprioceptive straight-ahead estimations. We assessed cognitive after-effects on the line bisection task. Fifty-four healthy participants were divided into six groups designated according to the exposure procedure used with each: 'Prism' (P) group; 'Vibration with a sensation of body rotation' (Vb) group; 'Vibration with a move illusion of the LED' (Vl) group; 'Association with a sensation of body rotation' (Ab) group; 'Association with a move illusion of the LED' (Al) group; and 'Control' (C) group. The main findings showed that prism adaptation applied alone or combined with vibration showed significant adaptation in visuo-manual open-loop pointing, visual straight-ahead and proprioceptive straight-ahead. Vibration alone produced significant after-effects on proprioceptive straight-ahead estimation in the Vl group. Furthermore all groups (except C group) showed a rightward neglect-like bias in line bisection following the training procedure. This is the first demonstration of cognitive after-effects following neck muscle vibration in healthy individuals. The simultaneous application of both methods did not produce significant greater after-effects than prism adaptation alone in both sensorimotor and cognitive tasks. These results are discussed in terms of transfer of sensorimotor plasticity to spatial cognition in healthy individuals.

Direct determination of the Boltzmann constant by an optical method.

We have recorded the Doppler profile of a well-isolated rovibrational line in the nu(2) band of (14)NH(3). Ammonia gas was placed in an absorption cell thermalized by a water-ice bath. By extrapolating to zero pressure, we have deduced the Doppler width which gives a first measurement of the Boltzmann constant k(B) by laser spectroscopy. A relative uncertainty of 2 x 10(-4) has been obtained. The present determination should be significantly improved in the near future and contribute to a new definition of the kelvin.

Long-distance frequency dissemination with a resolution of 10(-17).

We use a new technique to disseminate microwave reference signals along ordinary optical fiber. The fractional frequency resolution of a link of 86 km in length is 10(-17) for a one day integration time, a resolution higher than the stability of the best microwave or optical clocks. We use the link to compare the microwave reference and a CO2/OsO4 frequency standard that stabilizes a femtosecond laser frequency comb. This demonstrates a resolution of 3 x 10(-14) at 1 s. An upper value of the instability introduced by the femtosecond laser-based synthesizer is estimated as 1 x 10(-14) at 1 s.

[Post-antibiotic effect of three aminoglycosides against Klebsiella pneumoniae]. / Effet post-antibiotique de trois aminosides sur Klebsiella pneumoniae.

This paper introduces a new method to quantify post antibiotic effect. This method was applied to the study of the effect of three aminoglycosides antibiotics on seven strains of Klebsiella pneumoniae. The antimicrobial was removed by filtration, washing with peptone broth and neutralization by heparin. Growth curves were monitored by automated measurement of optical density with Urimat-ATB (bioMérieux). The inoculum fluctuation bias was eliminated with the help of a mathematical analysis of results. Absence of carry-over was controlled for each bacteria-antibiotic combination. A significant post antibiotic effect was observed with the three antibiotics after 2 hours exposure to a concentration equivalent to 2 x MIC. There was no significant difference between the 3 aminoglycosides tested.

[Study of the microbial multiplication in the muscle just after slaughter (author's transl)]. / Etude de la multiplication microbienne dans le muscle juste apres l'abattage.

The bactericidal or bacteriostatic activity of the serum, the muscle and the rabbit meat juice was followed after slaughter on animals vaccinated or not against E. coli, P. putida, Cl. perfringens. Rabbit serum is bactericidal against gram negative bacteria, P. putida and E. coli. On the contrary it is without effect on Cl. perfringens. Muscle has no inhibitory effect against E. coli and Cl. perfringens on animals vaccinated or not. P. putida is inhibited or partially eliminated from rabbit muscle just after slaughter. Vaccination does not increase the bacteriostatic or bactericidal activities of the sera, the meat juices and intact muscles.