It has been established that legged, off-road vehicles exhibit better mobility, obtain higher energy efficiency and provide more comfortable movement than those of tracked or wheeled vehicles while moving on rough terrain. Previous studies on legged mechanism design were performed by selecting the length of each link by trial and error or by certain optimization techniques where only a static force analysis was performed due to the complexity of the mechanisms. We found that these techniques can be inefficient and inaccurate. In this paper, we present the design and the optimization of a single degree-of-freedom 8-bar legged walking mechanism. We design the leg using the mechanism design theory because it offers a greater control on the output motion. Furthermore, a dynamic force analysis is performed to determine the torque applied on the input link. The optimization is set up to achieve two objectives: i) to minimize the energy needed by the system and ii) to maximize the stride length. The kinematics and dynamics of the optimized leg mechanism are compared to the one by trial-and-error. It shows that large improvements to the performance of the leg mechanism can be achieved. A prototype of the walking mechanism with 6 legs is built to demonstrate the performance.

A genetic linkage map of mustard (Brassica juncea) was developed using two double haploid populations produced from crosses between a low erucic cultivar “ZEM1” and two moderate erucic acid lines “Vniimk351” and “Vniimk405” with the use of SSR and SRAP markers. The linkage map of the ZEM1xVniimk351 population included 13 linkage groups with an overall length of 791 cM with an average marker interval of 5.7 cM. The linkage map of the ZEM1xVniimk405 population also contained 13 linkage groups with a distance of 623 cM and an average marker interval of 4.6 cM. Using the linkage maps for the two populations, QTLs were detected for seed oil, protein and fatty acids. QTL analysis for fatty acids indentified QTLs on LG1, 7 and 12 for the ZEM1xVniimk351 population and LG1, 3 and 4 for the ZEM1xVniimk405 population. Analysis for the seed oil and protein content in the ZEM1xVniimk351 population identified 2 QTLs on LG1 and LG4 and 1 QTL on LG1 respectively. The QTL analysis ZEM1xVniimk405 of oil and protein content identified 1 QTL for oil and protein on LG1. The variation of fatty acids was shown to be the result of monogenic inheritance of the FAE1 gene in both populations.

No description available.

Pattern of Linkage Disequilibrium (LD) is a major factor largely determining the power of association mapping studies. Along with nucleotide diversities and DNA polymorphism, knowledge of patterns of LD along the genome needs to be to known to effectively design association mapping studies. In this study, patterns of nucleotide diversity, population structure, LD was estimated in Norway spruce (Picea abies). The data used for this were 23 nuclear loci sequenced in around 90 individuals originating from natural populations of Norway spruce throughout the current distribution range in Sweden and Finland. The observed levels of nucleotide diversity are variable among loci varying between 0.002 and 0.008 if measured by average pairwise nucleotide diversity. Despite the samples stretching large part of Finland and Sweden there were no evidence for strong population structure. As in earlier studies LD decays fast with distance and the average pattern of the squared correlation of allele frequencies drops to less than 0.2 within 100bp. In order to put the data in perspective previously generated data sets were re-analyzed and compared to the inferred results.

It has been established that legged, off-road vehicles exhibit better mobility, obtain higher energy efficiency and provide more comfortable movement than those of tracked or wheeled vehicles while moving on rough terrain. Previous studies on legged mechanism design were performed by selecting the length of each link by trial and error or by certain optimization techniques where only a static force analysis was performed due to the complexity of the mechanisms. We found that these techniques can be inefficient and inaccurate. In this paper, we present the design and the optimization of a single degree-of-freedom 8-bar legged walking mechanism. We design the leg using the mechanism design theory because it offers a greater control on the output motion. Furthermore, a dynamic force analysis is performed to determine the torque applied on the input link. The optimization is set up to achieve two objectives: i) to minimize the energy needed by the system and ii) to maximize the stride length. The kinematics and dynamics of the optimized leg mechanism are compared to the one by trial-and-error. It shows that large improvements to the performance of the leg mechanism can be achieved. A prototype of the walking mechanism with 6 legs is built to demonstrate the performance.

A genetic linkage map of mustard (Brassica juncea) was developed using two double haploid populations produced from crosses between a low erucic cultivar “ZEM1” and two moderate erucic acid lines “Vniimk351” and “Vniimk405” with the use of SSR and SRAP markers. The linkage map of the ZEM1xVniimk351 population included 13 linkage groups with an overall length of 791 cM with an average marker interval of 5.7 cM. The linkage map of the ZEM1xVniimk405 population also contained 13 linkage groups with a distance of 623 cM and an average marker interval of 4.6 cM. Using the linkage maps for the two populations, QTLs were detected for seed oil, protein and fatty acids. QTL analysis for fatty acids indentified QTLs on LG1, 7 and 12 for the ZEM1xVniimk351 population and LG1, 3 and 4 for the ZEM1xVniimk405 population. Analysis for the seed oil and protein content in the ZEM1xVniimk351 population identified 2 QTLs on LG1 and LG4 and 1 QTL on LG1 respectively. The QTL analysis ZEM1xVniimk405 of oil and protein content identified 1 QTL for oil and protein on LG1. The variation of fatty acids was shown to be the result of monogenic inheritance of the FAE1 gene in both populations.

Thesis (Ph. D.)--University of Hawaii at Manoa, 1991. / Includes bibliographical references (leaves 128-132) / Microfiche. / xiii, 132 leaves, bound ill. 29 cm

Understanding the underlying genetic causes of adaptation to local conditions is one of the main goals of population genetics. A strong latitudinal cline in the phenotypic trait of bud set is observed in present day populations of Norway spruce (Picea abies (L.) Karst). The first step towards determining how this strong selection on adaptive traits translates at the loci underlying the trait was to use multilocus sequence data to gain information on the fundamental population genetic properties of Norway spruce. We determined that the level of LD was low and genetic diversity was in the low range. Coalescent simulations revealed a demographic scenario of a fairly old and severe bottleneck as consistent with the observed data. To examine the role of selection at genes putatively involved in the control of bud set we, again, used a multilocus data set to test for deviations from neutrality and demographic scenarios inferred from background loci. Different candidate genes were identified by using different approaches, highlighting the difficulty in predicting how local adaptation will manifest itself on different time scales and in rangewide samples. When examining properties important in the design of association studies, the inevitable next step in identifying genes involved in local adaptation, we found that previous estimates of a low level of LD were highly influenced by the joint analysis of several loci over a large distribution range and that estimates of LD was in fact heterogeneous across loci and increased within populations. In addition, we found that within species tests for deviations from neutral expectations were highly sensitive to sample size. Additional genomic sequence characterization in Norway spruce is necessary to provide more comprehensive sets of markers for association studies, also including gene promoters and non-genic regions of the genome. In the final paper we show that the HMPR method is effective in constructing libraries enriched for the single copy fraction of the genome when applied to the large and dominantly repetitive genome of Norway spruce. In summary, the studies presented in this thesis together constitute a foundation for future studies on adaptive evolution in Norway spruce.

The site frequency spectrum of mutations (SFS) and linkage disequilibrium (LD) are the two major sources of information in population genetics studies. In this study we focus on the levels of LD and the SFS and on the effect of sample size on summary statistics in 10 Scandinavian populations of Norway spruce. We found that previous estimates of a low level of LD were highly influenced by both sampling strategy and the fact that data from multiple loci were analyzed jointly. Estimates of LD were in fact heterogeneous across loci and increased within individual populations compared with the estimate from the total data. The variation in levels of LD among populations most likely reflects different demographic histories, although we were unable to detect population structure by using standard approaches. As in previous studies, we also found that the SFS-based test Tajima's D was highly sensitive to sample size, revealing that care should be taken to draw strong conclusions from this test when sample size is small. In conclusion, the results from this study are in line with recent studies in other conifers that have revealed a more complex and variable pattern of LD than earlier studies suggested and with studies in trees and humans that suggest that Tajima's D is sensitive to sample size. This has large consequences for the design of future association and population genetic studies in Norway spruce.

Bibliography: leaves 98-136 / viii, 152 leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Paediatrics, 1989