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91.
92.
Summary The plant-infection technique for the estimation of rhizobia, in which small-seeded hosts are grown on agar within test-tubes, is applicable to soils with a moderate rhizobial population (in the order of at least 100/g). Account might have to be taken of skips (less diluted: negative, when more diluted are positive) likely to result, at least in part, from unfavourable conditions for rhizobial survival, multiplication or nodulation. Because of such effects, a sparse population (in the order of (10/g) may not be detected even without dilution (1 g soil per plant tube). Localisation of rhizobia in the soil is likely to be important in determining contact with the plant roots in the dilution count and in sampling from the field. Difficulties with sparsely populated soils can be partly overcome by carefully conducted direct sowings of sterilised seed, preferably in the confines of cores, either left in the field or brought back to the glasshouse. 相似文献
93.
Howard K. Thompson Jr. Robert H. Peter Henry D. McIntosh 《Bulletin of mathematical biology》1966,28(2):167-179
Previously proposed formulae for the quantitative estimation of bidirectional shunts across ventricular septal defects require
determination of the oxygen contents of mixed venous, pulmonary artery, pulmonary venous, and aortic blood. Because these
formulae do not take into account the mixing of oxygenated with unoxygenated blood within the ventricles, their use must result
in underestimation of shunt flows in each direction. A mathematical model for a ventricular defect is examined, in which it
is assumed that mixing of blood occurs in each of six sites in the venae cavae or right atrium, right ventricle, pulmonary
artery, left atrium, left ventricle, and aorta. A total of fourteen streams of blood can flow from one to another of these
mixing sites. As long as complete mixing occurs in the six specified mixing sites, any degree of mixing or non-mixing of the
various streams is permitted. From the equations characterizing the model, formulae are derived in which the shunt flow in
each direction is expressed in terms of the oxygen contents in the six mixing sites and the fractions of blood which enter
the shunt from either side without prior mixing in a ventricular mixing site. The previously reported formulae, which apply
when no ventricular mixing is allowed to occur, lead to theoretical minimum values for the shunt flows in each direction.
At the opposite extreme where all the shunting blood is required to mix in a ventricle before entering the shunt, formulae
for maximum possible shunt flows are also obtained. The absolute values for the left-to-right and right-to-left shunt flows,
which must lie somewhere between the theoretical maximum and minimum values, cannot be computed from blood gas data alone.
This work was supported in part by grant HE-07563 from the National Heart Institute of the National Institutes of Health and
grants-in-aid from the American and North Carolina Heart Associations and the Life Insurance Medical Research Fund.
Work completed during tenure as U.S.P.H.S. post-doctoral fellow. 相似文献
94.
95.
Evidence on the Basis of the Centromere Effect in the Large Autosomes of Drosophila Melanogaster 总被引:1,自引:1,他引:0 下载免费PDF全文
Peter E. Thompson 《Genetics》1964,49(5):761-769
96.
97.
Robert Thompson 《BMJ (Clinical research ed.)》1959,2(5160):1179-1180
98.
99.
Valerie Del Thompson 《Zoo biology》1989,8(3):275-297
Twelve species of captive ungulates were studied to determine behavioral responses to the presence of a zookeeper within the exhibit and in front of the exhibit, with and without zoo visitors present. Significant differences in behavior occurred between species for nearly all behaviors observed. A significantly greater occurrence of vigilance and approach behavior was directed toward the zookeeper while within the exhibit relative to when the zookeeper stood in front of the exhibit. A significantly lower occurrence of eating or drinking occurred when the zookeeper was inside the exhibit. Significant differences occurred across size categories in the occurrence of approaching the zookeeper. The most frequently scored behavior was visual orientation. Statistically significant differences in the occurrence of visual orientation directed by females toward the zookeeper existed across size category, with more vigilance by species with larger body size. A statistically higher occurrence of vigilance toward the zookeeper was directed by female ungulates but not by males when the zoo was closed to the public. Although no statistical significance was found regarding the intraspecific vigilance of males, data on females revealed significant differences across species and across size categories. When data regarding vigilance toward the public were analyzed, statistically significant differences existed between species for females only. Likewise, when data regarding interspecific vigilance were examined, statistically significant differences were found across size categories for females, but not for males. The potential roles of vigilance in the wild are discussed in reference to its role in captivity. 相似文献
100.
Structure of the gene encoding peripherin, an NGF-regulated neuronal-specific type III intermediate filament protein 总被引:18,自引:0,他引:18
We have cloned the rat gene encoding peripherin, a neuronal-specific intermediate filament protein that is NGF-regulated. Determination of the complete sequence, including 821 nucleotides of the 5'-flanking region, allows us to make conclusions about the evolutionary origin of the peripherin gene, its homology with other intermediate filament proteins, and possible mechanisms of regulation of peripherin expression in neurons. The positions of the eight peripherin gene introns correspond to the intron patterns of desmin, vimentin, and GFAP, with one example of intron sliding. Together with protein sequence homologies, this conclusively demonstrates that peripherin is a type III intermediate filament protein. The peripherin promoter contains sequences homologous to regions of other NGF-regulated promoters, which may function in peripherin induction by NGF. 相似文献