排序方式: 共有11条查询结果,搜索用时 15 毫秒
1.
Germán A. Enciso Morris W. Hirsch Hal L. Smith 《Journal of Dynamics and Differential Equations》2008,20(1):115-132
Classical results in the theory of monotone semiflows give sufficient conditions for the generic solution to converge toward
an equilibrium or toward the set of equilibria (quasiconvergence). In this paper, we provide new formulations of these results
in terms of the measure-theoretic notion of prevalence, developed in Christensen (Israel J. Math., 13, 255–260, 1972) and Hunt et al. (Bull. Am. Math. Soc., 27, 217–238, 1992). For monotone reaction–diffusion systems with Neumann boundary conditions on convex domains, we show the
prevalence of the set of continuous initial conditions corresponding to solutions that converge to a spatially homogeneous
equilibrium. We also extend a previous generic convergence result to allow its use on Sobolev spaces. Careful attention is
given to the measurability of the various sets involved. 相似文献
2.
ALTMANN DORIS; ALTMANN KLAUS 《IMA Journal of Mathematical Control and Information》2000,17(2):137-146
Email: altmannd{at}rki.deEmail: altmann{at}mathematik.hu-berlin.de The approach of N Gay for estimating the coverage of a multivalentvaccine from antibody prevalence data in certain age cohortsis complemented by using computer aided elimination theory ofvariables. Hereby, Gay's usage of numerical approximation canbe replaced by exact formulae which are surprisingly nice, too. 相似文献
3.
Embedology 总被引:45,自引:0,他引:45
Mathematical formulations of the embedding methods commonly used for the reconstruction of attractors from data series are discussed. Embedding theorems, based on previous work by H. Whitney and F. Takens, are established for compact subsetsA of Euclidean space Rk. Ifn is an integer larger than twice the box-counting dimension ofA, then almost every map fromR
k
toR
n
, in the sense of prevalence, is one-to-one onA, and moreover is an embedding on smooth manifolds contained withinA. IfA is a chaotic attractor of a typical dynamical system, then the same is true for almost everydelay-coordinate map fromR
k
toR
n
. These results are extended in two other directions. Similar results are proved in the more general case of reconstructions which use moving averages of delay coordinates. Second, information is given on the self-intersection set that exists whenn is less than or equal to twice the box-counting dimension ofA. 相似文献
4.
5.
食盐与高血压发病 总被引:1,自引:0,他引:1
秦俊法 《广东微量元素科学》2014,(5):31-56
限盐被许多国家推荐作为一项降压措施,但盐与血压之间存在复杂的相关关系。从原发性高血压的危险因素、食盐与血压的关系,以及盐-血压关系分布模式3个方面综述了食盐在高血压发病中的地位。 相似文献
6.
Pan Yu Yibei Dai Jiantao Dong Luyan Zhang Ying Ping Xuchu Wang Danhua Wang Zhihua Tao 《Electrophoresis》2020,41(23):2015-2020
Factor V Leiden (FVLeiden) is a missense mutation of 1691 position (G1691A) in exon 10 of FV gene, and being a genetic risk for venous thrombosis. Currently, there are several PCR-based methods for detecting FVLeiden mutation; however, these methods have disadvantages such as time-consuming, cumbersome steps and potentially hazardous gels. The aims of present study were to develop a simple, time-saving, accurate, and gel-free method, called amplification refractory mutation system (ARMS) TaqMan real-time PCR, for detecting FVLeiden mutation. We severally designed two specific reverse primers for mutant and wild-type through intentional introduction of mismatched nucleotide at the penultimate 3′ position. Although target amplicon amplification efficiency is reduced, but another corresponding amplicon is almost completely inhibited. Then, specific TaqMan-probe was designed to detect target amplicon. Established method was used to detect 500 unselected samples in Han Chinese, the results showed 499 cases of wild-type and one heterozygote. Afterward, 50 randomly picked wild-type cases and one heterozygote were reexamined by bidirectional DNA sequencing, which is considered as “Gold standard method.” Exhilaratingly, the results detected by the two methods were completely consistent. At last, allelic frequency of FVLeiden was calculated the in Han Chinese. Given the above results, A FVLeiden heterozygote has been found in 500 random samples in Han Chinese, and the allelic frequency was 0.1%. In conclusion, the ARMS TaqMan real-time PCR is an ideal detecting system for genotyping FVLeiden mutation in clinical application, and FVLeiden mutation exists in Han Chinese despite extremely low prevalence. 相似文献
7.
Gaetano Cammilleri Andrea Pulvirenti Antonella Costa Stefania Graci Rosaria Collura Maria Drussilla Buscemi 《Natural product research》2020,34(1):158-161
AbstractA total of 1104 fish samples from markets of Sicily were analysed for the detection and species identification of Anisakidae nematodes. The preliminary analysis of the fish samples showed the presence of 2459 larvae. All the fish species revealed different prevalence of infestation, with a maximum of 100% for Lepidopus caudatus and a minimum of 4.5% in Sardina pilchardus. The 80% of the larvae examined by PCR-RFLP analysis belonged to Anisakis pegreffii species. The seasonal infestation trend of Anisakis was evaluated in all the fish sample examined. The results of the seasonal infestation trend showed a marked connection with the ecological aspects of the fish species examined. As far as we know, this work report for the first time important ecological aspects of Lepidopus caudatus specimens of South Mediterranean. This work could be useful to plan a seasonal fishing strategy aimed at reducing the health risks related to Anisakis. 相似文献
8.
Inevitably, there exist infected computers outside of the Internet. This paper aims to understand how infected external computers affect the spread of computer viruses. For that purpose, a new virus–antivirus spreading model, which takes into account the effect of infected/immune external computers, is established. A systematic study shows that, unlike most previous models, the proposed model admits no virus-free equilibrium and admits a globally asymptotically stable viral equilibrium. This result implies that it would be practically impossible to eradicate viruses on the Internet. As a result, inhibiting the virus prevalence to below an acceptable level would be the next best thing. A theoretical study reveals the effect of different parameters on the steady virus prevalence. On this basis, a number of suggestions are made so as to contain virus spreading. 相似文献
9.
目的 调查NRS2002 营养风险筛查工具用于部分内科患者的可行性及营养风险发生率在住院期间的改变。方法 对神经内科、消化内科、呼吸内科三个专科新入院且符合入选标准的180 例患者采用NRS2002 进行营养风险筛查,调查该工具的可行性及该部分患者在住院期间营养风险的变化。结果 入选患者中完全适用NRS2002 的患者比例为85.0%,评定率及完全适用率最低的均为神经内科;全部患者中,营养风险发生率从入院时的32.8%上升为出院时的38.3%,住院期间神经内科及消化内科的营养风险发生率升高,呼吸内科降低。结论 NRS2002应用于部分内科患者是可行的;医护人员应对患者在住院期间的营养风险进行监测,给予适当的干预,以降低住院期间营养风险发生率。 相似文献
10.
Roberto Castelli 《Communications in Nonlinear Science & Numerical Simulation》2012,17(2):804-816
This work concerns the role played by a couple of the planar circular restricted three-body problem in the approximation of the bicircular model. The comparison between the differential equations governing the dynamics leads to the definition of region of prevalence where one restricted model provides the best approximation of the four-body model. According to this prevalence, the patched three-body problem approximation is used to design first guess trajectories for a spacecraft travelling under the Sun-Earth-Moon gravitational influence. 相似文献