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1.
Beardsley T 《Nature》1985,313(6002):421
A physiologist and the chief veterinarian at the University of Western Ontario are facing possible prosecution for cruelty to animals because of an experiment in which a baboon was kept for several months in a restraining chair. The case is believed to be the first in Canada brought against researchers following complaints by an animal welfare group. The experiment was supported by the Canadian Medical Research Council and the Ontario Heart and Stroke Fund, and the protocol and laboratory were approved by the Canadian Council on Animal Care. 相似文献
2.
Beardsley T 《Nature》1985,313(5998):85
The dispute among federal agencies over regulation of commercial biotechnology has been addressed in the Federal Register by the Office of Science and Technology Policy (OSTP), which says the Recombinant DNA Advisory Committee of the National Institutes of Health should continue to oversee biomedical research in this area, while the Environmental Protection Agency should formulate regulatory policies for industry and resolve such issues as when a microorganism constitutes a new chemical substance. OSTP also proposes four new independent expert committees to advise the EPA, the Food and Drug Administration, the Department of Agriculture, and the National Science Foundation, and a Biotechnology Science Board to coordinate the work of the committees. 相似文献
3.
This paper is a case study of a major System Dynamics (SD) intervention in policy design in the Australian Taxation Office. The project, which lasted two years, tested a number of hypotheses regarding the application of Stafford Beer's Viable Systems Model (VSM) to the structure and process of the project. The paper reports that the success of the VSM within the ATO was qualified by political changes in the external environment. 相似文献
4.
Observation of rare-earth segregation in silicon nitride ceramics at subnanometre dimensions 总被引:2,自引:0,他引:2
Silicon nitride (Si3N4) ceramics are used in numerous applications because of their superior mechanical properties. Their intrinsically brittle nature is a critical issue, but can be overcome by introducing whisker-like microstructural features. However, the formation of such anisotropic grains is very sensitive to the type of cations used as the sintering additives. Understanding the origin of dopant effects, central to the design of high-performance Si3N4 ceramics, has been sought for many years. Here we show direct images of dopant atoms (La) within the nanometre-scale intergranular amorphous films typically found at grain boundaries, using aberration corrected Z-contrast scanning transmission electron microscopy. It is clearly shown that the La atoms preferentially segregate to the amorphous/crystal interfaces. First-principles calculations confirm the strong preference of La for the crystalline surfaces, which is essential for forming elongated grains and a toughened microstructure. Whereas principles of micrometre-scale structural design are currently used to improve the mechanical properties of ceramics, this work represents a step towards the atomic-level structural engineering required for the next generation of ceramics. 相似文献
5.
The population dynamics and decomposition activities of litter arthropods in an unmanaged sagehrush/bitterbrush habitat in southeastern Wyoming were assessed in 1986. The effects of sagebrush/bitterbrush management practices on litter arthropod communities and the role of these communities in decomposition were also assessed. Insecticide applications were used to selectively exclude arthropods in order to determine the ecological impact of these detritivores. Application of a herbicide, 2,4-D, was associated with increased arthropod populations for 30 days following treatment. Mowing increased arthropod densities at two different times, 10-30 days and 50 days post treatment, perhaps as a result of functional and numerical responses by litter arthropods. Elimination of arthropods from otherwise undisturbed shrub habitats by the use of broad-spectrum insecticides reduced the rate of litter decomposition during the growing season, indicating that these organisms play an important role in decomposition and nutrient cycling. 相似文献
6.
Thirty-nine previously unpublished reports of the endangered black-footed ferret from Wyoming are listed with dates, locations, number of animals, sources, and comments. 相似文献
7.
Linda Reinhard Henning Tidow Michael J. Clausen Poul Nissen 《Cellular and molecular life sciences : CMLS》2013,70(2):205-222
The Na+,K+-ATPase, or sodium pump, is well known for its role in ion transport across the plasma membrane of animal cells. It carries out the transport of Na+ ions out of the cell and of K+ ions into the cell and thus maintains electrolyte and fluid balance. In addition to the fundamental ion-pumping function of the Na+,K+-ATPase, recent work has suggested additional roles for Na+,K+-ATPase in signal transduction and biomembrane structure. Several signaling pathways have been found to involve Na+,K+-ATPase, which serves as a docking station for a fast-growing number of protein interaction partners. In this review, we focus on Na+,K+-ATPase as a signal transducer, but also briefly discuss other Na+,K+-ATPase protein–protein interactions, providing a comprehensive overview of the diverse signaling functions ascribed to this well-known enzyme. 相似文献
8.
Milada Stuchlová Horynová Milan Raška Henrik Clausen Jan Novak 《Cellular and molecular life sciences : CMLS》2013,70(5):829-839
Glycosylation abnormalities have been observed in autoimmune diseases and cancer. Here, we compare mechanisms of aberrant O-glycosylation, i.e., formation of Tn and sialyl-Tn structures, on MUC1 in breast cancer, and on IgA1 in an autoimmune disease, IgA nephropathy. The pathways of aberrant O-glycosylation, although different for MUC1 and IgA1, include dysregulation in glycosyltransferase expression, stability, and/or intracellular localization. Moreover, these aberrant glycoproteins are recognized by antibodies, although with different consequences. In breast cancer, elevated levels of antibodies recognizing aberrant MUC1 are associated with better outcome, whereas in IgA nephropathy, the antibodies recognizing aberrant IgA1 are part of the pathogenetic process. 相似文献
9.
Sexually antagonistic genetic variation for fitness in red deer 总被引:1,自引:0,他引:1
Foerster K Coulson T Sheldon BC Pemberton JM Clutton-Brock TH Kruuk LE 《Nature》2007,447(7148):1107-1110
Evolutionary theory predicts the depletion of genetic variation in natural populations as a result of the effects of selection, but genetic variation is nevertheless abundant for many traits that are under directional or stabilizing selection. Evolutionary geneticists commonly try to explain this paradox with mechanisms that lead to a balance between mutation and selection. However, theoretical predictions of equilibrium genetic variance under mutation-selection balance are usually lower than the observed values, and the reason for this is unknown. The potential role of sexually antagonistic selection in maintaining genetic variation has received little attention in this debate, surprisingly given its potential ubiquity in dioecious organisms. At fitness-related loci, a given genotype may be selected in opposite directions in the two sexes. Such sexually antagonistic selection will reduce the otherwise-expected positive genetic correlation between male and female fitness. Both theory and experimental data suggest that males and females of the same species may have divergent genetic optima, but supporting data from wild populations are still scarce. Here we present evidence for sexually antagonistic fitness variation in a natural population, using data from a long-term study of red deer (Cervus elaphus). We show that male red deer with relatively high fitness fathered, on average, daughters with relatively low fitness. This was due to a negative genetic correlation between estimates of fitness in males and females. In particular, we show that selection favours males that carry low breeding values for female fitness. Our results demonstrate that sexually antagonistic selection can lead to a trade-off between the optimal genotypes for males and females; this mechanism will have profound effects on the operation of selection and the maintenance of genetic variation in natural populations. 相似文献
10.