Avoidance of the photochemical production of oxygen atoms in one-dimensional, two-photon laser-induced fluorescence imaging.

We demonstrate that one-dimensional, two-photon laser-induced fluorescence imaging of oxygen atoms in flames can be achieved with reasonable signal intensities and spatial resolution but without the interference caused by the photolysis of O(2), by the use of a beam telescope instead of a focusing lens. The increase in probed volume (and concomitantly the number of excitable atoms) caused by the larger beam diameter in the telescope experiments offsets, to a certain extent, the loss in signal that is due to the reduced laser fluence. Further, the results show that the "correct" dependence of the fluorescence intensity on laser fluence (in this case quadratic) does not guarantee the absence of photochemistry.

Effects of the use of a morantel sustained release bolus in first and second year grazing cattle.

In an experiment carried out in 1981 and 1982, the effect of the use of a morantel sustained release bolus (Paratect bolus) on the weight gain and a number of parasitological parameters of cattle was studied. In the first year 42 calves were divided into 3 equal groups, one group was kept outside and treated with a bolus (B), the second group was kept outside and was not treated (C), while the third group remained indoors (I). Groups B and C were grazed separately on contaminated pasture.

[Effects of alternate grazing on faecal egg output of gastrointestinal nematodes and on the growth of calves and lambs].

During the period from 1975 to 1977, the faecal egg output of gastrointestinal nematodes and the gain in weight of a group of calves and a group of ewes with lambs on pastures alternately grazed by the two groups, were compared with the egg output and the gain in weight of a group of calves and a group of ewes with lambs not grazed alternately. The annual level of the egg output was identical in each comparable group. Variations in larval differentiation were observed between the groups grazed alternately or not.