19 research outputs found
Schistosoma Weinland, 1858 from Hippopotamus amphibius Linnaeus, 1758 in the Kruger National Park
Adults of Schistosoma edwardiense Thurston, 1964, were recovered from Hippopotamus amphibius in the Kruger National Park. Small round to oval Schistosoma margrebowiei-like eggs, presumed to be those of S. edwardiense, were found fairly frequently in the faeces of infected hippopotami together with a few Schistosoma haematobium-like eggs the identity of which remains uncertain.
Biomphalaria sp., exposed to the droppings of infected hippopotami, shed cercariae thought to be those of S. edwardiense. No evidence of schistosoma adults was found at necropsy in rodents exposed to these cercariae. The parasite appears to be host specific to the hippopotamus.
Arguments, based on biological and anatomical characteristics are put forward regarding Schistosoma hippopotami Thurston, 1963 as synonymous with Schistosoma mansoni.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi.
Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format
Schistosoma mattheei Veglia & LeRoux, 1929, egg output from cattle in a highly endemic area in the eastern Transvaal
The results of 6-month estimations of S. mattheei faecal egg counts on 513 cattle in a highly endemic area of the eastern Transvaal over a 2-year period are given. After an initial high egg output of short duration the egg counts stabilized at a low level. The frequency of high egg counts in young cattle which died naturally was more than twice that of all other cattle, suggesting that S. mattheei egg counts in highly endemic areas is debatable, and it is suggested that egg counts in man might follow a similar pattern.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi.
Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format
Hexatic-Herringbone Coupling at the Hexatic Transition in Smectic Liquid Crystals: 4- Renormalization Group Calculations Revisited
Simple symmetry considerations would suggest that the transition from the
smectic-A phase to the long-range bond orientationally ordered hexatic
smectic-B phase should belong to the XY universality class. However, a number
of experimental studies have constantly reported over the past twenty years
"novel" critical behavior with non-XY critical exponents for this transition.
Bruinsma and Aeppli argued in Physical Review Letters {\bf 48}, 1625 (1982),
using a renormalization-group calculation, that short-range
molecular herringbone correlations coupled to the hexatic ordering drive this
transition first order via thermal fluctuations, and that the critical behavior
observed in real systems is controlled by a `nearby' tricritical point. We have
revisited the model of Bruinsma and Aeppli and present here the results of our
study. We have found two nontrivial strongly-coupled herringbone-hexatic fixed
points apparently missed by those authors. Yet, those two new nontrivial
fixed-points are unstable, and we obtain the same final conclusion as the one
reached by Bruinsma and Aeppli, namely that of a fluctuation-driven first order
transition. We also discuss the effect of local two-fold distortion of the bond
order as a possible missing order parameter in the Hamiltonian.Comment: 1 B/W eps figure included. Submitted to Physical Review E. Contact:
[email protected]