Macquarie perch, an Australian native freshwater species, does not respond to hypophysation when caught from the wild, spawned and subsequently held in captivity. In this paper, the fatty acid ...composition of the liver, mature oocytes, muscle and diets of wild and tank-reared fish are compared. The fatty acid profiles of the two groups of fish were closely related to their diets, and of the fatty acid profiles, those of the liver showed the least variation between years. The most significant differences in the fatty acid profiles of the two groups were observed in the liver, in which tank-reared fish had more monoenes, largely 16:1
n − 7, but less
n − 6 fatty acids and a higher
n − 3 to
n − 6 ratio than did wild fish. Muscle differed from other tissues in that 16:0 and 16:1
n − 7 acids were present in greater amounts than 22:6
n − 3 and did not show a consistent variation between wild and tank-reared fish. In the mature oocytes of wild fish polyunsaturated fatty acids were present in consistent amounts between years. The mature oocytes of tank-reared fish had lower levels of
n − 6 fatty acids and as a result these oocytes had significantly higher
n − 3 to
n − 6 ratios compared with those of wild fish. Principal component analysis indicated that the fatty acid composition of all three tissues was clearly separable in the two groups of fish.
It is hypothesised that the low levels of
n − 6 fatty acids, in particular 20:4
n − 6, in the diet of tank-reared Macquarie perch, may be responsible for the lack of response to hypophysation techniques in these fish, owing to the lack of precursors for the synthesis of prostaglandins. It is also suggested that Macquarie perch, like its marine relatives, is incapable of de novo synthesis of the highly unsaturated fatty acids of the
n − 3 and
n − 6 series and has to rely on its diet for these fatty acids.
Several statistical methods of image reconstruction are described and objectively compared through the use of receiver-operating-characteristic (ROC) analysis based on a specified detection task ...performed by a human observer. The simulated imaging system is a multiple-pinhole coded-aperture system for dynamic cardiac imaging, and the objects represent cross sections of the left ventricle at end systole. The task is detection of a profusion representing an akinetic wall segment. Thirteen different reconstruction algorithms are considered. Human observers perform the specified task on this set of reconstructions, and the results are analyzed through the use of ROC analysis. The results show that the methods that utilize the largest amount of (accurate) prior information tend to perform the best
Comparison of glycolysis in Brugia pahangi and Onchocerca volvulus by 13C nuclear magnetic resonance (NMR) spectroscopy showed that the former organism is predominantly a lactate fermenter and the ...latter resembles more closely the metabolism of a mixed acid fermenter producing lactate, succinate, acetate, ethanol, formate and carbon dioxide. Both organisms synthesize glycogen as a storage carbohydrate. Glutaminolysis in both organisms proceeds by the delta-amino-butyrate shunt to produce succinate which is then further metabolized to acetate and carbon dioxide as end-products.
We investigate the effects of various types of prior information for use in medical image reconstruction. The setting in which this is done is reconstruction of an image (f) based on measured data ...(g), where the two are related via the linear imaging equation g = Hf, where H represents the point spread function of the imaging system. The system considered here is a multiple-pinhole coded-aperture imaging system. Because the dimension of g is much less than the dimension of f, we have a severely under-determined set of equations. A coded-aperture imaging system is simulated and reconstructions are performed. The object that we reconstruct is a digitized picture of the left ventricle and the surrounding heart muscle. This gives rise to a "nearly binary" picture. Comparisons of the various types of prior information are made.
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