Intracavity photoacoustic sensing of water vapor with a continuously tunable external-cavity quantum-cascade laser operating near 5.5 μm.

A gas sensor integrating a pulsed external-cavity quantum-cascade laser and a photoacoustic (PA) cell placed inside the laser cavity is described. The laser design allows a continuously tunable and mode-hop-free operation with an estimated instrument-limited linewidth of 0.063  cm in Littrow or Littman-Metcalf cavity configurations.

[Methods for studying the distribution of Monogenea in the gills of fishes].

The infection rate with monogeneans of different sites of fish gills was examined. The comparative analysis of average parts (in %) was made after [see text] Fisher where phi is a percentage in radians, n -- the number of fishes dissected, v -- degrees of freedom. It was shown statistically, that part (%) of dactylogyrids on II paris of the gills is significantly greater than parts from I and III pairs of the gills.

[Characteristics of the localization of Ancyrocephalus paradoxus (Monogenea) on the pike perch Stizostedion lucioperca].

In one summer old fishes of the pike perch, caught in the K urish Gulf of the Baltic Sea in August-September of 1984, at 100% infection with A. paradoxus 94% of monogeneans were localized under the lower anterior angle of the operculum on the lateral surface of the intergill space (isthmus). In fishes 1+ on the isthmus there were found 52%, in pike perches 2+ 42%, and in fishes 3+ 67% of worms.