Sex chromosomes in lizards   总被引：2，自引：0，他引：2  

C J Cole  C H Lowe  J W Wright 《Science (New York, N.Y.)》1967,155(765):1028-1029

Karyotypes of many species of the genus Sceloporus support the generalization that there are no morphologically recognizable sex chromosomes in lizards; however, there is a marked sexual dimorphism in the karyotypes of Sceloporus jarrovi and Sceloporus poinsetti. During meiosis in males, whose diploid number of chromosomes is 31, preferential segregation of chromosomes from a trivalent results in heterogamety.  相似文献   

Homologs of small nucleolar RNAs in Archaea     

Omer AD  Lowe TM  Russell AG  Ebhardt H  Eddy SR  Dennis PP 《Science (New York, N.Y.)》2000,288(5465):517-522

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Natural free-running period in vertebrate animal populations     

C H Lowe  D S Hinds  P J Lardner  K E Justice 《Science (New York, N.Y.)》1967,156(774):531-534

Regression analysis (analysis of covariance) is contrasted with the conventional "mean period length" for estimating the length of period of the spontaneous activity frequency (free-running period) in population samples of Gila monsters (Heloderma suspectum) and kangaroo rats (Dipodomys merriami) in the Sonoran Desert. The mean period length in each population does not differ significantly from 24:00 hours (P > .05) and it does not differ significantly (P > .05) between the species studied; the probability that the free-running period a(in constant dark) in natural populations of Gila monsters and kangaroo rats is different from 24:00.0 is less than 1 in 1000 (P < .001). The so-called "mean period length" is of little or no use for precise determination of the period and phase relationships in circadian rhythms; moreover, it is entirely without value for statistical testing of differences either within or between populations.  相似文献   

Monosodium glutamate: specific brain lesion questioned     

C U Lowe  M R Zavon  J W Olney  L G Sharpe 《Science (New York, N.Y.)》1970,167(920):1016-1017

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The Barrier to Internal Rotation in Ethane: A qualitative, intuitively useful explanation emerges from a comparison of different theoretical approaches     

Lowe JP 《Science (New York, N.Y.)》1973,179(4073):527-532

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Characterisation of germplasm accessions of Napier grass (pennisetum purpureum and P. purpureum×P. glaucum Hybrids) and comparison with farm clones using RAPD     

A.J. Lowe  W. Thorpe  A. Teale  J. Hanson 《Genetic Resources and Crop Evolution》2003,50(2):121-132

Fifty six germplasm accessions of the important East African fodder crop Napier grass, Pennisetum purpureum, and its hybrids with P. glaucum, were characterised using 67 random amplified polymorphic DNA (RAPD) fragments. No or very low intra-accession variation was found for 49 of the accessions examined, confirming field observations that this species is predominantly clonally propagated. Comparison of intra and inter-accession variation identified several groups of identical/similar accessions that could be targeted if the collection is to be rationalised, and also highlighted two misplantings of germplasm material during transfer to a field trial site. A neighbour joining dendrogram of Jaccard's similarity estimates, clearly separated 50 accessions of P. purpureum from three P. glaucum individuals, and placed six hybrid accessions in an intermediate position. These groupings were well supported by a nested AMOVA (P<0.001; 29.5% of total variance due to taxonomic delineation). The main group of P. purpureum individuals could be further differentiated into five sub-groups (designated East Africa, Southern Africa, USA1, USA2 and Miscellaneous, to reflect the majority membership of sub-groups) and examination of the within P. purpureum component of the nested AMOVA, found them to be significantly different (P<0.001; 18.8% of variance). Genetic diversity across all accessions was found to be fairly high (Shannon's diversity index 0.306) and thus the collection probably represents a wide genetic base for this species. In addition to germplasm accessions, 25 Kenyan farm clones were also analysed. A principal coordinate analysis found that all but one of the clones clustered with the main P. purpureum group of accessions, indicating that the majority are probably not interspecific hybrids. The origin and pedigree of clones is discussed based on genetic similarity amongst clones and to germplasm accessions.  相似文献   

Growth of hatchling earthworms in the presence of adults: interactions in laboratory culture     

Christopher N. Lowe  Kevin R. Butt 《Biology and Fertility of Soils》2002,35(3):204-209

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Understanding your client's decision-making process.          下载免费PDF全文

H Lowe  B Matthew 《The Canadian veterinary journal. La revue veterinaire canadienne》1996,37(2):119-122

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Risk factors associated with injuries in thoroughbred horses.   总被引：2，自引：0，他引：2  

H O Mohammed  T Hill  J Lowe 《Equine veterinary journal》1991,23(6):445-448

A case-control study was conducted on Thoroughbred horses to identify factors associated with the risk of breakdown on racetracks. A total of 310 cases (breakdowns) were identified from the Horse Identification Department records kept by the chief examining veterinarian of New York Racing Association. For each case, two control horses were selected randomly from the Daily Racing Form Inc. records. Multiple logistic regression analysis was used to identify and quantify the risk of factors associated with breakdown, while simultaneously controlling for the effect of other putative factors. Factors associated with risk of breakdown were: track (horses raced on Saratoga racetrack were at a lesser risk of breakdown), track composition/condition (turf tracks had a lower risk compared to dirt), number of seasons in race, racing in a later race, number of starts per year, the total number of starts, season (summer had a higher risk than winter or spring) and age of the horse.  相似文献   

Eel acetylcholinesterase inhibition studies with heteroarylphosphinates     

Claire N. Lieske  James H. Clark  Howard G. Meyer  Leigh Boldt  Martin D. Green  John R. Lowe  Walter E. Sultan  Peter Blumbergs  Matthew A. Priest 《Pesticide biochemistry and physiology》1984,22(3):285-294

The inhibition of eel acetylcholinesterase by the 4-nitrophenyl esters of 2-furyl(methyl)-, methyl(2-thienyl)-, di-2-furyl-, and di-2-thienylphosphinic acid (I, II, III, and IV, respectively) was investigated at pH 6.90 in 0.067 M phosphate buffer (25.0°C) using stopped-flow instrumentation and automated data processing. Our evaluation of the dissociation constant, K_d, the unimolecular bonding rate constant, k₂, and the bimolecular reaction constant, k_i, are the first reported values for these constants for alkyl/heteroaryl and diheteroaryl esters of phosphinic acids. The largest k_i value (19,330 M^?1 sec^?1) was observed for the reaction of I with the enzyme. The order for the remaining three is II > IV > III. There is no direct relationship between the hydrolysis rates of the esters and their anticholinesterase activities on eel acetylcholinesterase. Likewise, there is no direct relationship between their anticholinesterase activities and the LD₅₀ values in rats.  相似文献