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61.
Video Structure Analysis 总被引:2,自引:0,他引:2
Video structure analysis is a basic requirement for most content-based video editing and processing systems. This paper presents a fast video structure analysis method based on image segmentation in each frame, with region matching between frames. The structure analysis decomposes the video into several moving objects, including information about their colors, positions, shapes, movements, and lifetimes. The method also supports user interactions to improve the results. The result shows that this method is fast and stable and can complete video analyzinq interactivelv. 相似文献
62.
Li Tiegang Liu Zhenxia M. A. Hall Y. Saito S. Berne Cang Shuxi Cheng Zhenbo 《科学通报(英文版)》2002,47(7):599-603
The equatorial Pacific upwelling zone has been suspected of playing an important role in the global atmospheric CO2 changes associated with glacial-interglacial cycles.In order to assess the influencing scope of the surface water deglacial δ13C minimum in the tropical Iow-latitude Pacific,the core DGKS9603, collected from the middle Okinawa Trough, was examined for δ13C records of planktonic foraminifera N. dutertrei and G. ruber. The planktonic foraminiferal δ13C records show a clear decreasing event from 20 to 6 cal. kaBP., which is characterized by long duration of about 14 ka and amplitude shift of 0.4 × 10-3. Its minimum value occurred at 15.7 cai kaBP. The event shows fairly synchrony with the surface water deglacial δ13C minimum identiffed in the tropical Pacific and its marginal seas. Because there is no evidence in planktonic foraminiferal fauna and δ18O records for upwelling and river runoff enhancement,the broad deglacial δ13C minimum event in planktonic foraminiferal records revealed in core DGKS9603 might have been the direct influencing result of the deglacial surface water of the tropical Pacific. The identification for the event in the Okinawa Trough provides new evidence that the water evolution in the tropical low-latitude Pacific plays a key role in large regional, even global carbon cycle. 相似文献
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64.
1,2,4-Triazolidine-3,5-diones and the 3,5-isoxazolidinedione were observed to be potent inhibitors of rat lens aldose reductase activity. In vivo in streptozotocin-diabetic rats, selected agents at 20 mg/kg/day, orally for 21 days reduced significantly the sorbitol levels of rbc, lens and sciatic nerves, suggesting that these derivatives may have some usefulness to treat clinical complications of diabetes mellitus. 相似文献
65.
Carulla N Caddy GL Hall DR Zurdo J Gairí M Feliz M Giralt E Robinson CV Dobson CM 《Nature》2005,436(7050):554-558
Amyloid fibrils are thread-like protein aggregates with a core region formed from repetitive arrays of beta-sheets oriented parallel to the fibril axis. Such structures were first recognized in clinical disorders, but more recently have also been linked to a variety of non-pathogenic phenomena ranging from the transfer of genetic information to synaptic changes associated with memory. The observation that many proteins can convert into similar structures in vitro has suggested that this ability is a generic feature of polypeptide chains. Here we have probed the nature of the amyloid structure by monitoring hydrogen/deuterium exchange in fibrils formed from an SH3 domain using a combination of nuclear magnetic resonance spectroscopy and electrospray ionization mass spectrometry. The results reveal that under the conditions used in this study, exchange is dominated by a mechanism of dissociation and re-association that results in the recycling of molecules within the fibril population. This insight into the dynamic nature of amyloid fibrils, and the ability to determine the parameters that define this behaviour, have important implications for the design of therapeutic strategies directed against amyloid disease. 相似文献
66.
The genome of the social amoeba Dictyostelium discoideum 总被引:2,自引:0,他引:2
Eichinger L Pachebat JA Glöckner G Rajandream MA Sucgang R Berriman M Song J Olsen R Szafranski K Xu Q Tunggal B Kummerfeld S Madera M Konfortov BA Rivero F Bankier AT Lehmann R Hamlin N Davies R Gaudet P Fey P Pilcher K Chen G Saunders D Sodergren E Davis P Kerhornou A Nie X Hall N Anjard C Hemphill L Bason N Farbrother P Desany B Just E Morio T Rost R Churcher C Cooper J Haydock S van Driessche N Cronin A Goodhead I Muzny D Mourier T Pain A Lu M Harper D Lindsay R Hauser H James K Quiles M 《Nature》2005,435(7038):43-57
The social amoebae are exceptional in their ability to alternate between unicellular and multicellular forms. Here we describe the genome of the best-studied member of this group, Dictyostelium discoideum. The gene-dense chromosomes of this organism encode approximately 12,500 predicted proteins, a high proportion of which have long, repetitive amino acid tracts. There are many genes for polyketide synthases and ABC transporters, suggesting an extensive secondary metabolism for producing and exporting small molecules. The genome is rich in complex repeats, one class of which is clustered and may serve as centromeres. Partial copies of the extrachromosomal ribosomal DNA (rDNA) element are found at the ends of each chromosome, suggesting a novel telomere structure and the use of a common mechanism to maintain both the rDNA and chromosomal termini. A proteome-based phylogeny shows that the amoebozoa diverged from the animal-fungal lineage after the plant-animal split, but Dictyostelium seems to have retained more of the diversity of the ancestral genome than have plants, animals or fungi. 相似文献
67.
A mesoscale phytoplankton bloom in the polar Southern Ocean stimulated by iron fertilization 总被引:63,自引:0,他引:63
Boyd PW Watson AJ Law CS Abraham ER Trull T Murdoch R Bakker DC Bowie AR Buesseler KO Chang H Charette M Croot P Downing K Frew R Gall M Hadfield M Hall J Harvey M Jameson G LaRoche J Liddicoat M Ling R Maldonado MT McKay RM Nodder S Pickmere S Pridmore R Rintoul S Safi K Sutton P Strzepek R Tanneberger K Turner S Waite A Zeldis J 《Nature》2000,407(6805):695-702
Changes in iron supply to oceanic plankton are thought to have a significant effect on concentrations of atmospheric carbon dioxide by altering rates of carbon sequestration, a theory known as the 'iron hypothesis'. For this reason, it is important to understand the response of pelagic biota to increased iron supply. Here we report the results of a mesoscale iron fertilization experiment in the polar Southern Ocean, where the potential to sequester iron-elevated algal carbon is probably greatest. Increased iron supply led to elevated phytoplankton biomass and rates of photosynthesis in surface waters, causing a large drawdown of carbon dioxide and macronutrients, and elevated dimethyl sulphide levels after 13 days. This drawdown was mostly due to the proliferation of diatom stocks. But downward export of biogenic carbon was not increased. Moreover, satellite observations of this massive bloom 30 days later, suggest that a sufficient proportion of the added iron was retained in surface waters. Our findings demonstrate that iron supply controls phytoplankton growth and community composition during summer in these polar Southern Ocean waters, but the fate of algal carbon remains unknown and depends on the interplay between the processes controlling export, remineralisation and timescales of water mass subduction. 相似文献
68.
1 Introduction1 Bioinformatics is a rapidly expanding field involving a significant contribution from the data mining community. Many different problems are grouped into the general category of bioinformatics, including protein secondary structure prediction, drug discovery, DNA microarray analysis, gene prediction and genome analysis [17]. In this paper, we focus on two particular problems in which data mining can contribute: drug discovery and protein secondary structure prediction. Both … 相似文献
69.
70.
Pinocytotic vesicles and ion transport in plant cells 总被引:3,自引:0,他引:3