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31.
N.K. Schiller N.S. Weerasekara P. Zilla B.D. Reddy 《Computer methods in biomechanics and biomedical engineering》2013,16(6):773-781
Vascular anastomoses constitute a main factor in poor graft performance due to mismatches in distensibility between the host artery and the graft. This work aims at computational fluid–structure investigations of proximal and distal anastomoses of vein grafts and synthetic grafts. Finite element and finite volume models were developed and coupled with a user-defined algorithm. Emphasis was placed on the simplicity of the coupling algorithm. An artery and vein graft showed a larger dilation mismatch than an artery and synthetic graft. The vein graft distended nearly twice as much as the artery while the synthetic graft displayed only approximately half the arterial dilation. For the vein graft, luminal mismatching was aggravated by development of an anastomotic pseudo-stenosis. While this study focused on end-to-end anastomoses as a vehicle for developing the coupling algorithm, it may serve as useful point of departure for further investigations such as other anastomotic configurations, refined modelling of sutures and fully transient behaviour. 相似文献
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DAVID B. IRONS TYCHO ANKER-NILSSEN† ANTHONY J. GASTON‡ G. VERNON BYRD§ KNUD FALK¶ GRANT GILCHRIST‡ MARTTI HARIO MÅNS HJERNQUIST YURI V. KRASNOV†† ERS MOSBECH‡‡ BERGUR OLSEN§§ AEVAR PETERSEN¶¶ JAMES B. REID GREGORY J. ROBERTSON HALLVARD STRØM††† KENTON D. WOHL 《Global Change Biology》2008,14(7):1455-1463
We found that synchronous fluctuations of two congeneric seabird species across the entire Arctic and sub-Arctic regions were associated with changes in sea surface temperatures (SST) that were linked to two climate shifts, in 1977 and again in 1989. As the SST changes linked to climate shifts were congruent at the scale of ocean basins, fluctuations of these species occurred similarly at continental or basin scale. Changes in colony sizes were examined for a decade following climate shifts. The magnitude of the SST shift was more important than its direction in determining the subsequent rate of population change. Seabirds declined when the SST shift was large and increased when the shift was small, although the effect differed between the Arctic-breeding species and the more temperate-breeding congener. The Arctic species, Thick-billed Murre ( Uria lomvia ) increased most rapidly when SST warmed slightly, while the temperate species, Common Murre ( Uria aalge ) showed most rapid increase with moderate cooling. Both showed negative trends with large temperature shifts in either direction. This pattern was replicated during both climate oscillations. Negative population trends in seabirds presumably indicate the alteration of underlying food webs. Hence, similar widespread fluctuations in response to climate shifts are likely for other ecosystem components (marine mammals, fish, and invertebrates). 相似文献
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Chris Christiansen Thomas Mailund Christian NS Pedersen Martin Randers Martin Stig Stissing 《Algorithms for molecular biology : AMB》2006,1(1):16-13
Background
A number of algorithms have been developed for calculating the quartet distance between two evolutionary trees on the same set of species. The quartet distance is the number of quartets – sub-trees induced by four leaves – that differs between the trees. Mostly, these algorithms are restricted to work on binary trees, but recently we have developed algorithms that work on trees of arbitrary degree. 相似文献34.
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Weerasekara Lakshani Wijesooriya Kumudu Ranawana Kithsiri Anupama Thilini Rajapakse Jayantha 《Primates; journal of primatology》2021,62(4):629-635
Primates - Similar infectious agents may be shared among human and nonhuman primates due to their close proximity. Gastrointestinal parasitism is one of the main diseases which can be transmitted... 相似文献
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Poornima A. M. N. S. Weerasekara W. M. L. S. Vinobaba M. Karunarathna K. A. N. K. 《Primates; journal of primatology》2022,63(3):261-270
Primates - As the demand for resources has increased with the high population growth rate, people have been tempted to encroach on wildlife areas for activities such as logging, animal husbandry,... 相似文献