Soil amoebas as biological markers to estimate the quality of swimming pool waters

The legal biological survey of swimming pool waters is based on both the level of bacteriological contamination and the amount of material of fecal origin. The great number of soil amoebas and the occasional epidemiological risk involved led us to consider using these organisms as possible biological markers to estimate the quality of pool water and the extent of disinfection. During a 1-year survey of 54 public swimming pools, 765 superficial pool and tap water samples were collected. One portion (50 ml) drawn from 1-liter samples was filtered and cultured for amoebas. In specimens considered contaminated we detected at least 20 amoebas per liter, whereas uncontaminated samples contained fewer than 20 amoebas per liter. By keeping the threshold value voluntarily low, we were able to compare tap water with pool water and to monitor the quality of various disinfection procedures (i.e., chlorine, bromine, and Cu-Ag). The data suggest that the filters were not always protective against a high concentration of amoebas. Furthermore, these disinfection procedures were not equally efficient according to estimates based on biological criteria. In addition, the quality of swimming pool water also depends on the quality of its source tap water. Thus, the numeration of soil amoebas can be used as an additional biological marker to estimate the quality of swimming pool water.     

Forward traction in the correction of retrodisplaced maxilla

An external fixation apparatus immobilized to the skull has been used with satisfactory results in 15 cases of significant retrusion of the middle third of the face in which intermaxillary wiring and facial suspension had proved inadequate. The retrusion was a consequence of trauma or secondary to congenital malformation.This apparatus, developed by Delbet and Tessier, would be useful in difficult cases, such as for edentulous patients, and is an alternative to bone grafting.     

Greffes de cornée automatisées par laser femtoseconde optimisé et système de contrôle aberrométrique

We present a first evaluation of the results of the GRECO project which aims to conceive and realise an innovative device for ocular surgery by ultrafast pulse laser optimised for corneal grafting.     

Muscular response to the therapist and symptomatic improvement during biofeedback for tension headache

The relationship between muscular response to the therapist's presence and symptomatic improvement was studied during biofeedback. Thirty-two patients suffering from tension headaches received muscular biofeedback training of six sessions plus a follow-up session two months later. Patients' electro-myographic frontal response was measured prior to treatment both with and without the therapist present. A relationship was found between symptomatic improvement at follow-up and muscular response to the therapist's presence before treatment: patients showing a decrease of at least 10% in muscular tension response to the presence of their future therapist improved more regarding headache intensity than the patients showing increase or smaller variation of their EMG. A significant correlation of .59 was found between the frontal EMG response to therapist presence during the evaluation session and headache improvement at follow-up. The results suggest that the decrease of muscular tension during the first contact with the therapist could be an indicator of good prognosis, possibly because of an immediate positive therapeutic relationship and/or favorable expectancies concerning future benefit of treatment.The authors thank Mrs. G. Parisé for her assistance during the experimentation, Ms. M. Newman for her editorial corrections, and Ms. A. Khan for her secretarial work.     

Design in Arabidopsis thaliana of a synchronous system of floral induction by one long day

A system of one-shot induction of flowering in Arabidopsis thaliana, ecotype Columbia, is described. Plants from vernalized seeds are grown for 2 months in 8 h short days at an irradiance of 48 µmol m^?2 sec^?1 (fluorescent light only). At that age they can be induced to flower by exposure to either a single long day or a single displaced short day. Non-induced plants stay vegetative for at least a further month. Synchrony of induction among the individuals of the population exposed to one long day is of the same order as in the best classical model plants, that is, the fastest individuals are only 6 h ahead of the slowest ones. A further advantage of this system is the large size of plants at the time of induction, allowing easy analysis of changes in leaves, leaf exudate and shoot meristem. The design of such a synchronous system will allow the timings of gene activations and deactivations to be established in the different plant parts, before flowers are initiated.