997 resultados para Stewart, A. M. (Alexander Morrison), 1814-1875.


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The responsiveness to change of the Actical and ActiGraph accelerometers was assessed in children and adolescents. Participants (n=208) aged 6-16 years completed two simulated free-living protocols, one with primarily light-to-moderate physical activities (PA) and one with mostly moderate-to-vigorous PA. Time in sedentary, light, moderate, and vigorous PA was estimated using 8 previously developed cut-points (4 for Actical and 4 for ActiGraph) and 15-s and 30-s epochs. Accelerometer responsiveness for detecting differences in PA between protocols was assessed using standardized response means (SRM). SRM values >/=0.8 represented high responsiveness to change. Both accelerometers showed high responsiveness for all PA intensities (SRMs = 1.2-4.7 for Actical and 1.1-3.3 for ActiGraph). All cut-points and epoch lengths yielded high responsiveness, and choice of cut-points and epoch length had little effect on responsiveness. Thus, both the Actical and ActiGraph can detect change in PA in a simulated free-living setting, irrespective of cut-point selection or epoch length.

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This paper addresses the problem of singularity-free path planning for the six-degree-of-freedom parallel manipulator known as the Stewart platform manipulator. Unlike serial manipulators, the Stewart platform possesses singular configurations within the workspace where the manipulator is uncontrollable. An algorithm has been developed to construct continuous paths within the workspace of the manipulator by avoiding singularities and ill-conditioning. Given two end-poses of the manipulator, the algorithm finds out safe (well-conditioned) via points and plans a continuous path from the initial pose to the final one. When the two end-poses belong to different branches and no singularity-free path is possible, the algorithm indicates the impossibility of a valid path. A numerical example has also been presented as illustration of the path planning strategy.

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Earlier studies have shown that the speed of information transmission developed radically during the 19th century. The fast development was mainly due to the change from sailing ships and horse-driven coaches to steamers and railways, as well as the telegraph. Speed of information transmission has normally been measured by calculating the duration between writing and receiving a letter, or between an important event and the time when the news was published elsewhere. As overseas mail was generally carried by ships, the history of communications and maritime history are closely related. This study also brings a postal historical aspect to the academic discussion. Additionally, there is another new aspect included. In business enterprises, information flows generally consisted of multiple transactions. Although fast one-way information was often crucial, e.g. news of a changing market situation, at least equally important was that there was a possibility to react rapidly. To examine the development of business information transmission, the duration of mail transport has been measured by a systematic and commensurable method, using consecutive information circles per year as the principal tool for measurement. The study covers a period of six decades, several of the world's most important trade routes and different mail-carrying systems operated by merchant ships, sailing packets and several nations' steamship services. The main sources have been the sailing data of mail-carrying ships and correspondence of several merchant houses in England. As the world's main trade routes had their specific historical backgrounds with different businesses, interests and needs, the systems for information transmission did not develop similarly or simultaneously. It was a process lasting several decades, initiated by the idea of organizing sailings in a regular line system. The evolution proceeded generally as follows: originally there was a more or less irregular system, then a regular system and finally a more frequent regular system of mail services. The trend was from sail to steam, but both these means of communication improved following the same scheme. Faster sailings alone did not radically improve the number of consecutive information circles per year, if the communication was not frequent enough. Neither did improved frequency advance the information circulation if the trip was very long or if the sailings were overlapping instead of complementing each other. The speed of information transmission could be improved by speeding up the voyage itself (technological improvements, minimizing the waiting time at ports of call, etc.) but especially by organizing sailings so that the recipients had the possibility to reply to arriving mails without unnecessary delay. It took two to three decades before the mail-carrying shipping companies were able to organize their sailings in an optimal way. Strategic shortcuts over isthmuses (e.g. Panama, Suez) together with the cooperation between steamships and railways enabled the most effective improvements in global communications before the introduction of the telegraph.

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The emperor of our fatherland The changing national identity of the elite and the construction of the Finnish fatherland at the beginning of the autonomy This study addresses the question of changing national identity of the elite at the beginning of the autonomy (1808 1814) in Finland. Russia had conquered Finland from Sweden, but Finland was not incorporated into the Russian Empire. Instead, it was governed as separately administered area, and Finland retained its own (laws of the realm of Sweden) laws. The inclusion in the Russian Empire compelled the elite of Finland to deliberate their national identity; they had to determine whether they remained Swedes or became Finns or Russians. The elite chose to become Finns, which may seem obvious from the nowadays perspective, but it cannot be taken for granted that the Swedish speaking and noble elite converted their local Finnish identity into a new national identity. The basis of this study is constructive in a sense that identity is not seen as stable and constant. Theoretical background lies on Stuart Hall s writings on national identity, which offer good practical methods to study national identity. According to Hall identity is based mainly on difference , difference to others . In practice this means how elite began to define themselves in contrast to Swedes and Russians. The Finnish national identity was constructed in contrast to Swedes due to the political reasons. In order to avoid Russians suspicions Finns had to diverge from Sweden. Sweden had also gone trough coup d état, which was disliked by the elite of Finland. However, the attitudes of the elite towards Sweden remained somewhat ambiguous. Even if it was politically and rationally thinking wisest to draw away from Sweden, emotionally it was difficult. Russia, on the other hand, had been for centuries the archenemy of the Finns as well as all the Swedes. The fear of the Russians was mainly imaginary. Russians were seen as cruel barbarians who hated and resented Finns. The Finnish national identity was constructed above all in contrast to the Russians, for the difference to Russia was seen as a precondition for the existence of Finland. Respectively, the new position of Finland also required approaching towards Russia, which was in its nature very pragmatic. The elite contrived to get rid off its prejudice against Russians on intellectual level, but not on emotional level. At the beginning of the autonomy the primary loyalty of the elite was directed into the Finnish fatherland and its habitants. This was a radical ideological change, because traditionally the loyalty of the elite had focused on monarch and monarch s realm. However, the role of Alexander I was crucial. According to the elite the emperor had granted them a new fatherland. The former native country (Finland) was seen as a new fatherland instead of Sweden. The loyalty of the elite to the emperor generated from the reciprocal gratitude; Alexander I had treated their native country so mercifully. The elite felt strong personal responsibility for Finland s existence. The elite believed that the future of Finland rested on their shoulders. Alexander I had given them fatherland, but it was in the hands of the elite to construct the Finnish state and national spirit. The study of the Finnish national identity brings forth also that the national identity was constructed by emphasizing Finns civic rights. The civic rights were essential part of the construction of the Finnish national identity, for the difference between Finns and Russians was based on Finns own laws and privileges, which the emperor of the Russia had ensured.

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This paper presents an inverse dynamic formulation by the Newton–Euler approach for the Stewart platform manipulator of the most general architecture and models all the dynamic and gravity effects as well as the viscous friction at the joints. It is shown that a proper elimination procedure results in a remarkably economical and fast algorithm for the solution of actuator forces, which makes the method quite suitable for on-line control purposes. In addition, the parallelism inherent in the manipulator and in the modelling makes the algorithm quite efficient in a parallel computing environment, where it can be made as fast as the corresponding formulation for the 6-dof serial manipulator. The formulation has been implemented in a program and has been used for a few trajectories planned for a test manipulator. Results of simulation presented in the paper reveal the nature of the variation of actuator forces in the Stewart platform and justify the dynamic modelling for control.

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The parasitic protists in the genus Tritrichomonas cause significant disease in domestic cattle and cats. To assess the genetic diversity of feline and bovine isolates of Tritrichomonas foetus (Riedmuller, 1928) Wenrich and Emmerson, 1933, we used 10 different genetic regions, namely the protein coding genes of cysteine proteases 1,2 and 4-9 (CP1, 2, 4-9) involved in the pathogenesis of the disease caused by the parasite. The cytosolic malate dehydrogenase 1 (MDH1) and internal transcribed spacer region 2 of the rDNA unit (ITS2) were included as additional markers. The gene sequences were compared with those of Tritrichomonas suis (Davaine. 1875) Morgan and Hawkins, 1948 and Tritrichomonas mobilensis Culberson et al., 1986. The study revealed 100% identity for all 10 genes among all feline isolates (=T. foetus cat genotype), 100% identity among all bovine isolates (=T. foetus cattle genotype) and a genetic distinctness of 1% between the cat and cattle genotypes of T. foetus. The cattle genotype of T. foetus was 100% identical to T. suis at nine loci (CP1, 2,4-8, ITS2, MDH1). At CP9, three out of four T. suis isolates were identical to the T. foetus cattle genotype, while the T. suis isolate SUI-H3B sequence contained a single unique nucleotide substitution. Tritrichomonas mobilensis was 0.4% and 0.7% distinct from the cat and cattle genotypes of T. foetus, respectively. The genetic differences resulted in amino acid changes in the CP genes, most pronouncedly in CP2, potentially providing a platform for elucidation of genotype-specific host-pathogen interactions of T. foetus. On the basis of this data we judge T. suis and T. foetus to be subjective synonyms. For the first time, on objective nomenclatural grounds, the authority of T. suis is given to Davaine, 1875, rather than the commonly cited Gruby and Delafond, 1843. To maintain prevailing usage of T. foetus, we are suppressing the senior synomym T. suis Davaine, 1875 according to Article 23.9, because it has never been used as a valid name after 1899 and T. foetus is widely discussed as the cause of bovine trichomonosis. Thus bovine, feline and porcine isolates should all be given the name T. foetus. This promotes the stability of T. foetus for the veterinary and economically significant venereal parasite causing bovine trichomonosis. (C) 2012 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

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Contains business correspondence, accounts and documents relating to Jacob Franks of New York, his two sons, Moses and David, a nephew, Isaac, and a John Franks of Halifax, possibly a member of the family.