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1.
Many birds perform visual signals during their learned songs, but little is known about the interrelationship between visual and vocal displays. We show here that male brown-headed cowbirds (Molothrus ater) synchronize the most elaborate wing movements of their display with atypically long silent periods in their song, potentially avoiding adverse biomechanical effects on sound production. Furthermore, expiratory effort for song is significantly reduced when cowbirds perform their wing display. These results show a close integration between vocal and visual displays and suggest that constraints and synergistic interactions between the motor patterns of multimodal signals influence the evolution of birdsong. 相似文献
2.
D. R. Knott 《Euphytica》1990,50(2):155-158
Summary Eight stem rust (Puccinia graminis tritici Eriks. and Henn.) resistant lines (designated TICENA lines) that had been selected by Veiga et al. (1981) following gamma radiation of BH-1146 wheat (Triticum aestivum L.) were studied. Six of the lines were resistant to race 15B-1 of stem rust and susceptible to race 56, and proved to carry the gene Sr7a. TICENA 4 carries two unidentified genes, each giving resistance to one of the two races. TICENA 10 carries Sr6, Sr7a and an unidentified gene giving resistance to race 56 but not 15B-1. The results raise doubts about the supposed origin of the lines as mutants. 相似文献
3.
Kane Moyle Danielle Johnston Brenton Knott Roy Melville‐Smith Di Walker 《Journal of the World Aquaculture Society》2009,40(2):255-265
The effect of four stocking densities (30, 60, 100, and 150 lobsters/m2) on the growth and survival of Panulirus cygnus postpueruli was determined over a 112‐d grow‐out trial. Agonistic behavior at each experimental density was recorded using infrared filming. Survival and growth decreased with increasing density, although this trend was only significant between the lowest (30/m2) and the highest densities (150/m2) (P < 0.05) at the conclusion of the grow‐out trial. Density had no significant effect on apparent feed intake but significantly affected food conversion ratios (FCR) across all four densities, with FCR being best at 30/m2 and worst at 150/m2. The number and frequency of agonistic encounters per tank differed significantly with density, with agonistic encounters being highest at 150/m2 and lowest at 30/m2. Agonistic encounters coincided with the crepuscular foraging pattern of postpueruli. The reduction in survival and growth of postpueruli at the highest density (150/m2) can be attributed to the significant increase in the number of agonistic encounters. This study supports that P. cygnus postpueruli should be stocked at densities less than 100/m2 in order to minimize the negative effect of density on growth and survival. 相似文献
4.
Tenesa A Knott SA Ward D Smith D Williams JL Visscher PM 《Journal of animal science》2003,81(3):617-623
The association between genetic marker alleles was estimated for two regions of the bovine genome from a random sample of 50 young dairy bulls born in the United Kingdom between 1988 and 1995. Microsatellite marker genotypes were obtained for six markers on chromosome 2 and seven markers on chromosome 6, spanning 38 and 20 cM, respectively. Two different methods, which do not require family information, were used to estimate population haplotype frequencies. Haplotype frequencies were estimated for pairs of loci using the expectation-maximization algorithm and for all linked loci using a Bayesian approach via a Markov chain-Monte Carlo algorithm. Significant (P = 0.0007) linkage disequilibrium was detected between pairs of loci in syntenic groups (that is, loci in the same linkage group), extending to about 10 cM. No significant linkage disequilibrium was detected between markers in nonsyntenic regions. Given the observed level of linkage disequilibrium, mapping methods based on population-wide association might provide a better resolution than traditional quantitative trait loci mapping methods in the U.K. dairy cattle population and may reduce the required sample sizes of the experiments. 相似文献
5.
Jann Th. Martinsohn Paul Raymond Trey Knott Kevin A. Glover Einar Eg Nielsen Lars Bonde Eriksen Rob Ogden John Casey Jordi Guillen 《Fish and Fisheries》2019,20(2):391-401
Evidence from DNA‐analysis is commonplace in human criminal investigations, and while it is increasingly being used in wildlife crime, to date, its application to control and enforcement activities in fisheries and aquaculture has only been sporadic. Contemporary DNA‐analysis tools are capable of addressing a broad range of compliance issues, species identification, mislabelling of fish products, determining the origin of catches and the farm of origin of aquaculture escapees. Such applications have the potential to ensure traceability along the fish product supply chain and to combat consumer fraud and Illegal, Unreported and Unregulated fishing. Nevertheless, DNA‐analysis is not yet used routinely in investigations into compliance with fisheries and aquaculture legislation. One potential reason for this is that DNA‐analysis techniques may have been regarded as too expensive. However, costs have plummeted over the past decade prompting us to objectively assess whether the costs associated with routine use of DNA‐analysis techniques for fisheries and aquaculture control and enforcement activities do constitute an impediment. Based on a number of recent fisheries and aquaculture compliance investigations that incorporated DNA‐analysis, our results indicate that the use of genetic analysis was justified and worthwhile in all cases examined. We therefore conclude that the costs associated with DNA‐analysis do not represent a barrier to the routine adoption of DNA‐analysis techniques in fisheries and aquaculture compliance investigations. Thus, control and enforcement agencies should be encouraged to use such techniques routinely. 相似文献
6.
Swadling Daniel S. Knott Nathan A. Rees Matthew J. Davis Andrew R. 《Landscape Ecology》2019,34(10):2337-2352
Landscape Ecology - Whilst the composition and arrangement of habitats within landscape mosaics are known to be important determinants of biodiversity patterns, the influence of seascape patterning... 相似文献
7.
Post-emergent herbicidal activity of cineole derivatives 总被引:1,自引:0,他引:1
Allan F. M. Barton Brenton R. Clarke Bernard Dell Allan R. Knight 《Journal of pest science》2014,87(3):531-541
Essential oils are being investigated as potential herbicides or to provide leads to new environmentally and socially acceptable herbicides. Novel hydroxy and ester derivatives of 1,8-cineole and 1,4-cineole were synthesised, by chemical and biological methods, and have shown pre-emergence herbicidal activity against annual ryegrass and radish. Effects on post-emergence activity of these derivatives, as well as 1,8-cineole, eucalyptus oil and the carboxylic acids from which the esters were derived, against annual ryegrass and radish, are reported here. Results suggest that reduced root and shoot growth observed in pre-emergence herbicidal bioassays were due to post-emergence activity rather than delayed germination. All tested substances had a dose-dependent, post-emergence herbicidal activity against annual ryegrass and radish with many derivatives showing improved activity relative to 1,8-cineole and high-cineole eucalyptus oil. However, results do not support the postulate that cineole esters would be more active than their respective carboxylic acid and the hydroxy cineole. Phytotoxicity of ester derivatives may be due to metabolic cleavage of the esters to the hydroxy cineole and carboxylic acid within the plant. 相似文献
8.
9.
van Schaik CP Ancrenaz M Borgen G Galdikas B Knott CD Singleton I Suzuki A Utami SS Merrill M 《Science (New York, N.Y.)》2003,299(5603):102-105
Geographic variation in some aspects of chimpanzee behavior has been interpreted as evidence for culture. Here we document similar geographic variation in orangutan behaviors. Moreover, as expected under a cultural interpretation, we find a correlation between geographic distance and cultural difference, a correlation between the abundance of opportunities for social learning and the size of the local cultural repertoire, and no effect of habitat on the content of culture. Hence, great-ape cultures exist, and may have done so for at least 14 million years. 相似文献
10.
Handheld computers are widely used in clinical practice, and their use in both human medical education and veterinary medical education is increasing, especially, for the former, in activities involving point-of-care access. This article references the insights that can be obtained from the usage and activities that are gaining a strong foothold in human medical education. Handheld computer technology gives students access to a large and changing knowledge base for clinical practice, especially when they are geographically dispersed. Differences in use between education and practice largely relate to the importance clinicians place on patient information. Student use focuses on progress mapping and ready access to clinical reference material. Suggestions are made for future use in medical education. 相似文献