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The effects of free radicals and hypotaurine on the development of bovine embryos produced by in vitro fertilization of in vitro-matured oocytes were examined. Embryos that developed to the 4- to 6-cell stage after in vitro fertilization were cultured without feeder cells in TCM199 medium supplemented with 1% calf serum (CS) under either 5% C[O.sub.2] in air or 5% [O.sub.2], 5% C[O.sub.2] and 90% [N.sub.2]. The percentages of blastocysts (including early, expanding, and hatched stages) that developed under 5% [O.sub.2] was higher (P < .01) than the percentage of those that developed under 20% [O.sub.2]. The respective percentages in 5% vs 20% [O.sub.2] concentration were as follows: blastocysts (d 8), 49% vs 17%; expanded blastocysts (d 8), 19% vs 6%; hatched blastocysts (d 10), 16% vs 0%. The development of embryos to blastocysts was suppressed (P < .05) when oxygen radicals were generated in culture medium by 2,2[inches]-azobis(2-amidinopropane) dihydrochloride (AAPH) under both 5% and 20% [O.sub.2]. The addition of hypotaurine permitted the development of embryos to blastocyst stage in medium with AAPH only under 5% [O.sub.2] (P < .05), but superoxide dismutase (SOD) did not permit the development of embryos to blastocysts. Alternatively, when embryos were cultured in medium without AAPH, the rates of development into blastocysts under 20% [O.sub.2] increased (P [less than] .05) by the addition of hypotaurine and SOD. However, under 5% [O.sub.2], the rates of blastocyst formation were not improved by addition of hypotaurine and SOD. Moreover, the cell numbers of blastocysts cultured in medium containing hypotaurine were greater (P < .01) than those of blastocysts cultured in medium without hypotaurine. It is concluded that hypotaurine may exert beneficial effects on in vitro development of bovine embryos under both 20% [O.sub.2] and 5% [O.sub.2] of gaseous conditions. Key Words: Bovine, Embryos, Oxygen Concentration, In Vitro Development, Hypotaurine

A metric study of 71 Japanese and 106 Australian aboriginal precontemporary crania was undertaken using direct measurements and cephalograms. Compared with Australian aboriginals, the Japanese are characterized by smaller cranial length, cranial base length, nasal floor length, palatal length, mandibular dimensions (except symphysis height), facial depth, posterior face height, and facial profile angle and larger cranial breadth and height, maxillary breadth, palatal breadth, anterior face height, and occlusal and mandibular plane angles. These differences confirm the previously described brachycephalic tendency in aboriginals and the dolichocephalic form in the Japanese. The differences are also consistent with the expected functional differences between the Australian aboriginal hunter-gatherer group masticating more resistant food with larger, more anteriorly located, more powerful masseter muscles and the Japanese group masticating less resistant food with correspondingly less robust masticatory musculature. The results highlight the differences in craniofacial morphology between groups with different genetic backgrounds subjected to significantly different environmental influences. KEY WORDS: JAPANESE, AUSTRALIAN ABORIGINALS, CRANIOFACIAL MORPHOLOGY, SKELETAL STUDIES, Craniofacial variation within and between populations results from complex interactions between genetic and environmental factors operating during the formation and growth of the skull. Comparisons of the craniofacial morphology of [...]

In this work, we consider narrow band partial response (NBPR) systems for (1, 7) RLL code. As a new type of (1, 7) PRML system, a PR(1, 1.5, 0, -1.5, -1) system called a modified MEEPR4 (MMEEPR4) which contains a spectral null below the Nyquist frequency is proposed. We compared the performances of 8/9 (0, 4, 4) PR4, (1, 7) EEPR4, (1, 7) MEEPR4 and (1, 7) MMEEPR4 in recording systems with both electronic and medium noise characterized by Thurlings' model. Medium noise power was corrected using the code magnetic transition probability. Thus the average medium noise power for code-2/3 (1, 7) was at a 20% smaller than that of code-8/9 (0, 4, 4). To verify the practical use of this system, we defined the broader constraints and calculated the error propagation. It is clear that the (1, 7) MEEPR4 system does not satisfy the broader constraints because it generates no quasi-catastrophic trellis sequence. Simulation results indicate that the narrow-band (1, 7) MMEEPR4 system provides a significant improvement over 8/9 (0, 4, 4) PR4 and (1, 7) EEPR4 and avoids the signal band extension for a 2/3 code-rate without a loss in performance.