排序方式: 共有34条查询结果,搜索用时 109 毫秒
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Paul Dekker 《Foundations of Science》2016,21(2):377-380
This comment on Erik Claes values his treatment of in-depth interviews to gain a better understanding of how volunteers make sense of their activities, but it questions the representativeness, meaningfulness and civicness of what is found. Meaning as deep personal commitment to an objective value (Susan Wolf) is probably quite exceptional. The values and goals of Claes’s volunteers are deeply human and wide-ranging, but too ignorant of disagreement, power and politics to be called civic. 相似文献
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T. P. Dekker H. L. van Boxtel E. A. Vos G. J. Garssen 《Cellular and molecular life sciences : CMLS》1979,35(6):847-848
Summary A method is described for the determination of glutamate oxaloacetate transaminase (GOT) activity in sperm plasma from boars and bulls as a test for fertilizing ability.Publication A-336 of the Research Institute for Animal Husbandry Schoonoord. 相似文献
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The Istituto e Museo di Storia della Scienza, Florence, Italy, possesses an astrolabe with five latitude plates that is now attributed to the Duisburg workshop of Gerard Mercator. Although it is known that Mercator made instruments, this is the first surviving example to be identified. Another latitude plate is shown to come from the workshop of the Florentine, Giovan Battista Giusti. A seventh plate, possibly engraved by Rumold Mercator, provides the only known Mercatorian polar stereographic projection. The role of Egnazio Danti, cosmographer to the Grand Duke of Tuscany, in the acquisition of the astrolabe in about 1570 is considered. 相似文献
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Damtew Elias van Mierlo Barbara Lie Rico Struik Paul Leeuwis Cees Lemaga Berga Smart Christine 《Systemic Practice and Action Research》2020,33(1):111-134
Systemic Practice and Action Research - There has been strong research interest in designing and testing learning approaches for enhancing and sustaining the capacity of communities to manage... 相似文献
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Cees H. Elzinga 《Journal of Classification》2005,22(1):87-118
This paper presents new representations of token sequences, with and without
associated quantities, in Euclidean space. The representations are free of assumptions
about the nature of the sequences or the processes that generate them. Algorithms and
applications from the domains of structured interviews and life histories are discussed. 相似文献
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Eelkema R Pollard MM Vicario J Katsonis N Ramon BS Bastiaansen CW Broer DJ Feringa BL 《Nature》2006,440(7081):163
Nanomachines of the future will require molecular-scale motors that can perform work and collectively induce controlled motion of much larger objects. We have designed a synthetic, light-driven molecular motor that is embedded in a liquid-crystal film and can rotate objects placed on the film that exceed the size of the motor molecule by a factor of 10,000. The changes in shape of the motor during the rotary steps cause a remarkable rotational reorganization of the liquid-crystal film and its surface relief, which ultimately causes the rotation of submillimetre-sized particles on the film. 相似文献
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Ruban AV Wentworth M Yakushevska AE Andersson J Lee PJ Keegstra W Dekker JP Boekema EJ Jansson S Horton P 《Nature》2003,421(6923):648-652
Photosystem II (PSII) is a key component of photosynthesis, the process of converting sunlight into the chemical energy of life. In plant cells, it forms a unique oligomeric macrostructure in membranes of the chloroplasts. Several light-harvesting antenna complexes are organized precisely in the PSII macrostructure-the major trimeric complexes (LHCII) that bind 70% of PSII chlorophyll and three minor monomeric complexes-which together form PSII supercomplexes. The antenna complexes are essential for collecting sunlight and regulating photosynthesis, but the relationship between these functions and their molecular architecture is unresolved. Here we report that antisense Arabidopsis plants lacking the proteins that form LHCII trimers have PSII supercomplexes with almost identical abundance and structure to those found in wild-type plants. The place of LHCII is taken by a normally minor and monomeric complex, CP26, which is synthesized in large amounts and organized into trimers. Trimerization is clearly not a specific attribute of LHCII. Our results highlight the importance of the PSII macrostructure: in the absence of one of its main components, another protein is recruited to allow it to assemble and function. 相似文献