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991.
张德福 《江苏技术师范学院学报》2007,13(3):51-54
在扼要综述《翻译批评导论》主要内容的基础上,指出该书具有系统性、创新性、简洁性、深刻性等鲜明特点,是我国第一部较为全面系统研究翻译批评的学术专著,对翻译批评研究具有里程碑的意义。 相似文献
992.
Demands for public participation in technical decision-making are currently high on the agenda of Science & Technology Studies. It is assumed that the democratisation of technical decision-making processes generally leads to more socially desirable and acceptable outcomes. While this may be true in certain cases, this assumption cannot be generalised. I will discuss the case of the so-called ‘South African AZT debate’. The controversy started when President Thabo Mbeki, after reading some scientific papers on the toxicity of AZT, decided to bar the use of the drug in the public health sector as a means to reduce the transmission of HIV from mothers to children. While the scientific mainstream accepts the effectiveness of AZT in reducing the risk of vertical HIV transmission, a few maverick scientists reject the clinical evidence and argue that the risks of using AZT by far outweigh its benefits. Based on various textual sources and using the ‘Periodic Table of Expertises’ developed by Collins and Evans, Mbeki’s expertise at the time of his intervention into the technical question whether AZT is a medicine or a poison can be classified as primary source knowledge. It is shown that this type of expertise is insufficient for technical decision-making. Mbeki’s primary source knowledge legitimated his presentation of the claims of maverick scientists as a serious contribution to the debate—with tragic consequences for tens of thousands of babies. 相似文献
993.
Rapid discharge connects Antarctic subglacial lakes 总被引:5,自引:0,他引:5
The existence of many subglacial lakes provides clear evidence for the widespread presence of water beneath the East Antarctic ice sheet, but the hydrology beneath this ice mass is poorly understood. Such knowledge is critical to understanding ice flow, basal water transfer to the ice margin, glacial landform development and subglacial lake habitats. Here we present ice-sheet surface elevation changes in central East Antarctica that we interpret to represent rapid discharge from a subglacial lake. Our observations indicate that during a period of 16 months, 1.8 km3 of water was transferred over 290 km to at least two other subglacial lakes. While viscous deformation of the ice roof above may moderate discharge, the intrinsic instability of such a system suggests that discharge events are a common mode of basal drainage. If large lakes, such as Lake Vostok or Lake Concordia, are pressurizing, it is possible that substantial discharges could reach the coast. Our observations conflict with expectations that subglacial lakes have long residence times and slow circulations, and we suggest that entire subglacial drainage basins may be flushed periodically. The rapid transfer of water between lakes would result in large-scale solute and microbe relocation, and drainage system contamination from in situ exploration is, therefore, a distinct risk. 相似文献
994.
Klussmann M Iwamura H Mathew SP Wells DH Pandya U Armstrong A Blackmond DG 《Nature》2006,441(7093):621-623
Ever since Pasteur noticed that tartrate crystals exist in two non-superimposable forms that are mirror images of one another--as are left and right hands--the phenomenon of chirality has intrigued scientists. On the molecular level, chirality often has a profound impact on recognition and interaction events and is thus important to biochemistry and pharmacology. In chemical synthesis, much effort has been directed towards developing asymmetric synthesis strategies that yield product molecules with a significant excess of either the left-handed or right-handed enantiomer. This is usually achieved by making use of chiral auxiliaries or catalysts that influence the course of a reaction, with the enantiomeric excess (ee) of the product linearly related to the ee of the auxiliary or catalyst used. In recent years, however, an increasing number of asymmetric reactions have been documented where this relationship is nonlinear, an effect that can lead to asymmetric amplification. Theoretical models have long suggested that autocatalytic processes can result in kinetically controlled asymmetric amplification, a prediction that has now been verified experimentally and rationalized mechanistically for an autocatalytic alkylation reaction. Here we show an alternative mechanism that gives rise to asymmetric amplification based on the equilibrium solid-liquid phase behaviour of amino acids in solution. This amplification mechanism is robust and can operate in aqueous systems, making it an appealing proposition for explaining one of the most tantalizing examples of asymmetric amplification-the development of high enantiomeric excess in biomolecules from a presumably racemic prebiotic world. 相似文献
995.
Moran K Backman J Brinkhuis H Clemens SC Cronin T Dickens GR Eynaud F Gattacceca J Jakobsson M Jordan RW Kaminski M King J Koc N Krylov A Martinez N Matthiessen J McInroy D Moore TC Onodera J O'Regan M Pälike H Rea B Rio D Sakamoto T Smith DC Stein R St John K Suto I Suzuki N Takahashi K Watanabe M Yamamoto M Farrell J Frank M Kubik P Jokat W Kristoffersen Y 《Nature》2006,441(7093):601-605
The history of the Arctic Ocean during the Cenozoic era (0-65 million years ago) is largely unknown from direct evidence. Here we present a Cenozoic palaeoceanographic record constructed from >400 m of sediment core from a recent drilling expedition to the Lomonosov ridge in the Arctic Ocean. Our record shows a palaeoenvironmental transition from a warm 'greenhouse' world, during the late Palaeocene and early Eocene epochs, to a colder 'icehouse' world influenced by sea ice and icebergs from the middle Eocene epoch to the present. For the most recent approximately 14 Myr, we find sedimentation rates of 1-2 cm per thousand years, in stark contrast to the substantially lower rates proposed in earlier studies; this record of the Neogene reveals cooling of the Arctic that was synchronous with the expansion of Greenland ice (approximately 3.2 Myr ago) and East Antarctic ice (approximately 14 Myr ago). We find evidence for the first occurrence of ice-rafted debris in the middle Eocene epoch (approximately 45 Myr ago), some 35 Myr earlier than previously thought; fresh surface waters were present at approximately 49 Myr ago, before the onset of ice-rafted debris. Also, the temperatures of surface waters during the Palaeocene/Eocene thermal maximum (approximately 55 Myr ago) appear to have been substantially warmer than previously estimated. The revised timing of the earliest Arctic cooling events coincides with those from Antarctica, supporting arguments for bipolar symmetry in climate change. 相似文献
996.
Zenker M Mayerle J Lerch MM Tagariello A Zerres K Durie PR Beier M Hülskamp G Guzman C Rehder H Beemer FA Hamel B Vanlieferinghen P Gershoni-Baruch R Vieira MW Dumic M Auslender R Gil-da-Silva-Lopes VL Steinlicht S Rauh M Shalev SA Thiel C Ekici AB Winterpacht A Kwon YT Varshavsky A Reis A 《Nature genetics》2005,37(12):1345-1350
Johanson-Blizzard syndrome (OMIM 243800) is an autosomal recessive disorder that includes congenital exocrine pancreatic insufficiency, multiple malformations such as nasal wing aplasia, and frequent mental retardation. We mapped the disease-associated locus to chromosome 15q14-21.1 and identified mutations, mostly truncating ones, in the gene UBR1 in 12 unrelated families with Johanson-Blizzard syndrome. UBR1 encodes one of at least four functionally overlapping E3 ubiquitin ligases of the N-end rule pathway, a conserved proteolytic system whose substrates include proteins with destabilizing N-terminal residues. Pancreas of individuals with Johanson-Blizzard syndrome did not express UBR1 and had intrauterine-onset destructive pancreatitis. In addition, we found that Ubr1(-/-) mice, whose previously reported phenotypes include reduced weight and behavioral abnormalities, had an exocrine pancreatic insufficiency, with impaired stimulus-secretion coupling and increased susceptibility to pancreatic injury. Our findings indicate that deficiency of UBR1 perturbs the pancreas' acinar cells and other organs, presumably owing to metabolic stabilization of specific substrates of the N-end rule pathway. 相似文献
997.
Levitus M Waisfisz Q Godthelp BC de Vries Y Hussain S Wiegant WW Elghalbzouri-Maghrani E Steltenpool J Rooimans MA Pals G Arwert F Mathew CG Zdzienicka MZ Hiom K De Winter JP Joenje H 《Nature genetics》2005,37(9):934-935
The protein predicted to be defective in individuals with Fanconi anemia complementation group J (FA-J), FANCJ, is a missing component in the Fanconi anemia pathway of genome maintenance. Here we identify pathogenic mutations in eight individuals with FA-J in the gene encoding the DEAH-box DNA helicase BRIP1, also called FANCJ. This finding is compelling evidence that the Fanconi anemia pathway functions through a direct physical interaction with DNA. 相似文献
998.
Global analysis of protein phosphorylation in yeast 总被引:1,自引:0,他引:1
999.
A unique, complex trackway has been discovered in Scotland: it was made roughly 330 million years ago by a huge, six-legged water scorpion that was about 1.6 m long and a metre wide. To my knowledge, this is not only the largest terrestrial trackway of a walking arthropod to be found so far, but is also the first record of locomotion on land for a species of Hibbertopterus (Eurypterida). This evidence of lumbering movement indicates that these giant arthropods, now extinct, could survive out of water at a time when the earliest tetrapods were making their transition to the land. 相似文献
1000.